Fix missing common BSS symbols

Resolves #128

.cargo/config.toml

@@ -0,0 +1,5 @@
+[target.x86_64-pc-windows-msvc]
+linker = "rust-lld"
+
+[target.aarch64-pc-windows-msvc]
+linker = "rust-lld"

.github/workflows/build.yaml

@@ -30,6 +30,8 @@ jobs:
         uses: dtolnay/rust-toolchain@stable
         with:
           components: clippy
+      - name: Cache Rust workspace
+        uses: Swatinem/rust-cache@v2
       - name: Cargo check
         run: cargo check --all-features --all-targets
       - name: Cargo clippy
@@ -85,6 +87,8 @@ jobs:
         uses: actions/checkout@v4
       - name: Setup Rust toolchain
         uses: dtolnay/rust-toolchain@stable
+      - name: Cache Rust workspace
+        uses: Swatinem/rust-cache@v2
       - name: Cargo test
         run: cargo test --release --all-features
 
@@ -142,11 +146,19 @@ jobs:
         uses: actions/checkout@v4
       - name: Install cargo-zigbuild
         if: matrix.build == 'zigbuild'
-        run: pip install ziglang==0.13.0 cargo-zigbuild==0.19.1
+        run: |
+          python3 -m venv .venv
+          . .venv/bin/activate
+          echo PATH=$PATH >> $GITHUB_ENV
+          pip install ziglang==0.13.0 cargo-zigbuild==0.19.1
       - name: Setup Rust toolchain
         uses: dtolnay/rust-toolchain@stable
         with:
           targets: ${{ matrix.target }}
+      - name: Cache Rust workspace
+        uses: Swatinem/rust-cache@v2
+        with:
+          key: ${{ matrix.target }}
       - name: Cargo build
         run: >
           cargo ${{ matrix.build }} --profile ${{ env.BUILD_PROFILE }} --target ${{ matrix.target }} 
@@ -198,6 +210,10 @@ jobs:
         uses: dtolnay/rust-toolchain@stable
         with:
           targets: ${{ matrix.target }}
+      - name: Cache Rust workspace
+        uses: Swatinem/rust-cache@v2
+        with:
+          key: ${{ matrix.target }}
       - name: Cargo build
         run: >
           cargo build --profile ${{ env.BUILD_PROFILE }} --target ${{ matrix.target }} 

.gitignore

@@ -3,10 +3,6 @@ target/
 **/*.rs.bk
 generated/
 
-# cargo-mobile
-.cargo/
-/gen
-
 # macOS
 .DS_Store
 

Cargo.lock

@@ -395,6 +395,15 @@ version = "0.22.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "72b3254f16251a8381aa12e40e3c4d2f0199f8c6508fbecb9d91f575e0fbb8c6"
 
+[[package]]
+name = "bimap"
+version = "0.6.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "230c5f1ca6a325a32553f8640d31ac9b49f2411e901e427570154868b46da4f7"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "bit-set"
 version = "0.6.0"
@@ -1517,15 +1526,15 @@ dependencies = [
 
 [[package]]
 name = "futures-core"
-version = "0.3.30"
+version = "0.3.31"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dfc6580bb841c5a68e9ef15c77ccc837b40a7504914d52e47b8b0e9bbda25a1d"
+checksum = "05f29059c0c2090612e8d742178b0580d2dc940c837851ad723096f87af6663e"
 
 [[package]]
 name = "futures-io"
-version = "0.3.30"
+version = "0.3.31"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a44623e20b9681a318efdd71c299b6b222ed6f231972bfe2f224ebad6311f0c1"
+checksum = "9e5c1b78ca4aae1ac06c48a526a655760685149f0d465d21f37abfe57ce075c6"
 
 [[package]]
 name = "futures-lite"
@@ -1542,9 +1551,9 @@ dependencies = [
 
 [[package]]
 name = "futures-macro"
-version = "0.3.30"
+version = "0.3.31"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "87750cf4b7a4c0625b1529e4c543c2182106e4dedc60a2a6455e00d212c489ac"
+checksum = "162ee34ebcb7c64a8abebc059ce0fee27c2262618d7b60ed8faf72fef13c3650"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1553,21 +1562,21 @@ dependencies = [
 
 [[package]]
 name = "futures-sink"
-version = "0.3.30"
+version = "0.3.31"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9fb8e00e87438d937621c1c6269e53f536c14d3fbd6a042bb24879e57d474fb5"
+checksum = "e575fab7d1e0dcb8d0c7bcf9a63ee213816ab51902e6d244a95819acacf1d4f7"
 
 [[package]]
 name = "futures-task"
-version = "0.3.30"
+version = "0.3.31"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "38d84fa142264698cdce1a9f9172cf383a0c82de1bddcf3092901442c4097004"
+checksum = "f90f7dce0722e95104fcb095585910c0977252f286e354b5e3bd38902cd99988"
 
 [[package]]
 name = "futures-util"
-version = "0.3.30"
+version = "0.3.31"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3d6401deb83407ab3da39eba7e33987a73c3df0c82b4bb5813ee871c19c41d48"
+checksum = "9fa08315bb612088cc391249efdc3bc77536f16c91f6cf495e6fbe85b20a4a81"
 dependencies = [
  "futures-core",
  "futures-io",
@@ -2852,7 +2861,7 @@ dependencies = [
 
 [[package]]
 name = "objdiff-cli"
-version = "2.2.2"
+version = "2.3.4"
 dependencies = [
  "anyhow",
  "argp",
@@ -2874,10 +2883,11 @@ dependencies = [
 
 [[package]]
 name = "objdiff-core"
-version = "2.2.2"
+version = "2.3.4"
 dependencies = [
  "anyhow",
  "arm-attr",
+ "bimap",
  "byteorder",
  "console_error_panic_hook",
  "console_log",
@@ -2913,7 +2923,7 @@ dependencies = [
 
 [[package]]
 name = "objdiff-gui"
-version = "2.2.2"
+version = "2.3.4"
 dependencies = [
  "anyhow",
  "bytes",

Cargo.toml

@@ -13,7 +13,7 @@ strip = "debuginfo"
 codegen-units = 1
 
 [workspace.package]
-version = "2.2.2"
+version = "2.3.4"
 authors = ["Luke Street <luke@street.dev>"]
 edition = "2021"
 license = "MIT OR Apache-2.0"

config.schema.json

@@ -133,6 +133,13 @@
         },
         "metadata": {
           "ref": "#/$defs/metadata"
+        },
+        "symbol_mappings": {
+          "type": "object",
+          "description": "Manual symbol mappings from target to base.",
+          "additionalProperties": {
+            "type": "string"
+          }
         }
       }
     },

deny.toml

@@ -70,7 +70,6 @@ feature-depth = 1
 # A list of advisory IDs to ignore. Note that ignored advisories will still
 # output a note when they are encountered.
 ignore = [
-    "RUSTSEC-2024-0370",
     #{ id = "RUSTSEC-0000-0000", reason = "you can specify a reason the advisory is ignored" },
     #"a-crate-that-is-yanked@0.1.1", # you can also ignore yanked crate versions if you wish
     #{ crate = "a-crate-that-is-yanked@0.1.1", reason = "you can specify why you are ignoring the yanked crate" },
@@ -240,7 +239,7 @@ allow-git = []
 
 [sources.allow-org]
 # github.com organizations to allow git sources for
-github = ["encounter"]
+github = ["notify-rs"]
 # gitlab.com organizations to allow git sources for
 gitlab = []
 # bitbucket.org organizations to allow git sources for

objdiff-cli/src/cmd/diff.rs

@@ -102,7 +102,12 @@ pub fn run(args: Args) -> Result<()> {
                     let unit_path =
                         PathBuf::from_str(u).ok().and_then(|p| fs::canonicalize(p).ok());
 
-                    let Some(object) = project_config.objects.iter_mut().find_map(|obj| {
+                    let Some(object) = project_config
+                        .units
+                        .as_deref_mut()
+                        .unwrap_or_default()
+                        .iter_mut()
+                        .find_map(|obj| {
                             if obj.name.as_deref() == Some(u) {
                                 resolve_paths(obj);
                                 return Some(obj);
@@ -121,7 +126,8 @@ pub fn run(args: Args) -> Result<()> {
                             }
 
                             None
-                    }) else {
+                        })
+                    else {
                         bail!("Unit not found: {}", u)
                     };
 
@@ -129,7 +135,13 @@ pub fn run(args: Args) -> Result<()> {
                 } else if let Some(symbol_name) = &args.symbol {
                     let mut idx = None;
                     let mut count = 0usize;
-                    for (i, obj) in project_config.objects.iter_mut().enumerate() {
+                    for (i, obj) in project_config
+                        .units
+                        .as_deref_mut()
+                        .unwrap_or_default()
+                        .iter_mut()
+                        .enumerate()
+                    {
                         resolve_paths(obj);
 
                         if obj
@@ -148,7 +160,7 @@ pub fn run(args: Args) -> Result<()> {
                     }
                     match (count, idx) {
                         (0, None) => bail!("Symbol not found: {}", symbol_name),
-                        (1, Some(i)) => &mut project_config.objects[i],
+                        (1, Some(i)) => &mut project_config.units_mut()[i],
                         (2.., Some(_)) => bail!(
                             "Multiple instances of {} were found, try specifying a unit",
                             symbol_name
@@ -303,7 +315,7 @@ fn find_function(obj: &ObjInfo, name: &str) -> Option<SymbolRef> {
     None
 }
 
-#[allow(dead_code)]
+#[expect(dead_code)]
 struct FunctionDiffUi {
     relax_reloc_diffs: bool,
     left_highlight: HighlightKind,
@@ -758,7 +770,7 @@ impl FunctionDiffUi {
         self.scroll_y += self.per_page / if half { 2 } else { 1 };
     }
 
-    #[allow(clippy::too_many_arguments)]
+    #[expect(clippy::too_many_arguments)]
     fn print_sym(
         &self,
         out: &mut Text<'static>,

objdiff-cli/src/cmd/report.rs

@@ -94,7 +94,7 @@ fn generate(args: GenerateArgs) -> Result<()> {
     };
     info!(
         "Generating report for {} units (using {} threads)",
-        project.objects.len(),
+        project.units().len(),
         if args.deduplicate { 1 } else { rayon::current_num_threads() }
     );
 
@@ -103,7 +103,7 @@ fn generate(args: GenerateArgs) -> Result<()> {
     let mut existing_functions: HashSet<String> = HashSet::new();
     if args.deduplicate {
         // If deduplicating, we need to run single-threaded
-        for object in &mut project.objects {
+        for object in project.units.as_deref_mut().unwrap_or_default() {
             if let Some(unit) = report_object(
                 object,
                 project_dir,
@@ -116,7 +116,9 @@ fn generate(args: GenerateArgs) -> Result<()> {
         }
     } else {
         let vec = project
-            .objects
+            .units
+            .as_deref_mut()
+            .unwrap_or_default()
             .par_iter_mut()
             .map(|object| {
                 report_object(
@@ -132,7 +134,7 @@ fn generate(args: GenerateArgs) -> Result<()> {
     }
     let measures = units.iter().flat_map(|u| u.measures.into_iter()).collect();
     let mut categories = Vec::new();
-    for category in &project.progress_categories {
+    for category in project.progress_categories() {
         categories.push(ReportCategory {
             id: category.id.clone(),
             name: category.name.clone(),

objdiff-core/Cargo.toml

@@ -17,35 +17,36 @@ crate-type = ["cdylib", "rlib"]
 
 [features]
 all = ["config", "dwarf", "mips", "ppc", "x86", "arm", "bindings"]
-any-arch = [] # Implicit, used to check if any arch is enabled
+any-arch = ["config", "dep:bimap", "dep:strum", "dep:similar", "dep:flagset", "dep:log", "dep:memmap2", "dep:byteorder", "dep:num-traits"] # Implicit, used to check if any arch is enabled
-config = ["globset", "semver", "serde_json", "serde_yaml"]
+config = ["dep:bimap", "dep:globset", "dep:semver", "dep:serde_json", "dep:serde_yaml", "dep:serde", "dep:filetime"]
-dwarf = ["gimli"]
+dwarf = ["dep:gimli"]
-mips = ["any-arch", "rabbitizer"]
+mips = ["any-arch", "dep:rabbitizer"]
-ppc = ["any-arch", "cwdemangle", "cwextab", "ppc750cl"]
+ppc = ["any-arch", "dep:cwdemangle", "dep:cwextab", "dep:ppc750cl"]
-x86 = ["any-arch", "cpp_demangle", "iced-x86", "msvc-demangler"]
+x86 = ["any-arch", "dep:cpp_demangle", "dep:iced-x86", "dep:msvc-demangler"]
-arm = ["any-arch", "cpp_demangle", "unarm", "arm-attr"]
+arm = ["any-arch", "dep:cpp_demangle", "dep:unarm", "dep:arm-attr"]
-bindings = ["serde_json", "prost", "pbjson"]
+bindings = ["dep:serde_json", "dep:prost", "dep:pbjson", "dep:serde", "dep:prost-build", "dep:pbjson-build"]
-wasm = ["bindings", "console_error_panic_hook", "console_log"]
+wasm = ["bindings", "any-arch", "dep:console_error_panic_hook", "dep:console_log", "dep:wasm-bindgen", "dep:tsify-next", "dep:log"]
 
 [package.metadata.docs.rs]
 features = ["all"]
 
 [dependencies]
 anyhow = "1.0"
-byteorder = "1.5"
+bimap = { version = "0.6", features = ["serde"], optional = true }
-filetime = "0.2"
+byteorder = { version = "1.5", optional = true }
-flagset = "0.4"
+filetime = { version = "0.2", optional = true }
-log = "0.4"
+flagset = { version = "0.4", optional = true }
-memmap2 = "0.9"
+log = { version = "0.4", optional = true }
-num-traits = "0.2"
+memmap2 = { version = "0.9", optional = true }
+num-traits = { version = "0.2", optional = true }
 object = { version = "0.36", features = ["read_core", "std", "elf", "pe"], default-features = false }
 pbjson = { version = "0.7", optional = true }
 prost = { version = "0.13", optional = true }
-serde = { version = "1.0", features = ["derive"] }
+serde = { version = "1.0", features = ["derive"], optional = true }
-similar = { version = "2.6", default-features = false }
+similar = { version = "2.6", default-features = false, optional = true }
-strum = { version = "0.26", features = ["derive"] }
+strum = { version = "0.26", features = ["derive"], optional = true }
-wasm-bindgen = "0.2"
+wasm-bindgen = { version = "0.2", optional = true }
-tsify-next = { version = "0.5", default-features = false, features = ["js"] }
+tsify-next = { version = "0.5", default-features = false, features = ["js"], optional = true }
 console_log = { version = "1.0", optional = true }
 console_error_panic_hook = { version = "0.1", optional = true }
 
@@ -76,5 +77,5 @@ unarm = { version = "1.6", optional = true }
 arm-attr = { version = "0.1", optional = true }
 
 [build-dependencies]
-prost-build = "0.13"
+prost-build = { version = "0.13", optional = true }
-pbjson-build = "0.7"
+pbjson-build = { version = "0.7", optional = true }

objdiff-core/build.rs

@@ -1,6 +1,11 @@
-use std::path::{Path, PathBuf};
-
 fn main() {
+    #[cfg(feature = "bindings")]
+    compile_protos();
+}
+
+#[cfg(feature = "bindings")]
+fn compile_protos() {
+    use std::path::{Path, PathBuf};
     let root = PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("protos");
     let descriptor_path = root.join("proto_descriptor.bin");
     println!("cargo:rerun-if-changed={}", descriptor_path.display());

objdiff-core/src/arch/mips.rs

@@ -83,7 +83,7 @@ impl ObjArch for ObjArchMips {
         &self,
         address: u64,
         code: &[u8],
-        _section_index: usize,
+        section_index: usize,
         relocations: &[ObjReloc],
         line_info: &BTreeMap<u64, u32>,
         config: &DiffObjConfig,
@@ -140,11 +140,18 @@ impl ObjArch for ObjArchMips {
                     | OperandType::cpu_label
                     | OperandType::cpu_branch_target_label => {
                         if let Some(reloc) = reloc {
-                            if matches!(&reloc.target_section, Some(s) if s == ".text")
+                            // If the relocation target is within the current function, we can
-                                && reloc.target.address > start_address
+                            // convert it into a relative branch target. Note that we check
-                                && reloc.target.address < end_address
+                            // target_address > start_address instead of >= so that recursive
+                            // tail calls are not considered branch targets.
+                            let target_address =
+                                reloc.target.address.checked_add_signed(reloc.addend);
+                            if reloc.target.orig_section_index == Some(section_index)
+                                && matches!(target_address, Some(addr) if addr > start_address && addr < end_address)
                             {
-                                args.push(ObjInsArg::BranchDest(reloc.target.address));
+                                let target_address = target_address.unwrap();
+                                args.push(ObjInsArg::BranchDest(target_address));
+                                branch_dest = Some(target_address);
                             } else {
                                 push_reloc(&mut args, reloc)?;
                                 branch_dest = None;

objdiff-core/src/arch/mod.rs

@@ -34,7 +34,11 @@ pub enum DataType {
 
 impl DataType {
     pub fn display_bytes<Endian: ByteOrder>(&self, bytes: &[u8]) -> Option<String> {
-        if self.required_len().is_some_and(|l| bytes.len() < l) {
+        // TODO: Attempt to interpret large symbols as arrays of a smaller type,
+        // fallback to intrepreting it as bytes.
+        // https://github.com/encounter/objdiff/issues/124
+        if self.required_len().is_some_and(|l| bytes.len() != l) {
+            log::warn!("Failed to display a symbol value for a symbol whose size doesn't match the instruction referencing it.");
             return None;
         }
 

objdiff-core/src/bindings/diff.rs

@@ -70,9 +70,13 @@ impl FunctionDiff {
         //     let (_section, symbol) = object.section_symbol(symbol_ref);
         //     Symbol::from(symbol)
         // });
-        let instructions = symbol_diff.instructions.iter().map(InstructionDiff::from).collect();
+        let instructions = symbol_diff
+            .instructions
+            .iter()
+            .map(|ins_diff| InstructionDiff::new(object, ins_diff))
+            .collect();
         Self {
-            symbol: Some(Symbol::from(symbol)),
+            symbol: Some(Symbol::new(symbol)),
             // diff_symbol,
             instructions,
             match_percent: symbol_diff.match_percent,
@@ -90,8 +94,8 @@ impl DataDiff {
     }
 }
 
-impl<'a> From<&'a ObjSymbol> for Symbol {
+impl Symbol {
-    fn from(value: &'a ObjSymbol) -> Self {
+    pub fn new(value: &ObjSymbol) -> Self {
         Self {
             name: value.name.to_string(),
             demangled_name: value.demangled_name.clone(),
@@ -122,29 +126,29 @@ fn symbol_flags(value: ObjSymbolFlagSet) -> u32 {
     flags
 }
 
-impl<'a> From<&'a ObjIns> for Instruction {
+impl Instruction {
-    fn from(value: &'a ObjIns) -> Self {
+    pub fn new(object: &ObjInfo, instruction: &ObjIns) -> Self {
         Self {
-            address: value.address,
+            address: instruction.address,
-            size: value.size as u32,
+            size: instruction.size as u32,
-            opcode: value.op as u32,
+            opcode: instruction.op as u32,
-            mnemonic: value.mnemonic.clone(),
+            mnemonic: instruction.mnemonic.clone(),
-            formatted: value.formatted.clone(),
+            formatted: instruction.formatted.clone(),
-            arguments: value.args.iter().map(Argument::from).collect(),
+            arguments: instruction.args.iter().map(Argument::new).collect(),
-            relocation: value.reloc.as_ref().map(Relocation::from),
+            relocation: instruction.reloc.as_ref().map(|reloc| Relocation::new(object, reloc)),
-            branch_dest: value.branch_dest,
+            branch_dest: instruction.branch_dest,
-            line_number: value.line,
+            line_number: instruction.line,
-            original: value.orig.clone(),
+            original: instruction.orig.clone(),
         }
     }
 }
 
-impl<'a> From<&'a ObjInsArg> for Argument {
+impl Argument {
-    fn from(value: &'a ObjInsArg) -> Self {
+    pub fn new(value: &ObjInsArg) -> Self {
         Self {
             value: Some(match value {
                 ObjInsArg::PlainText(s) => argument::Value::PlainText(s.to_string()),
-                ObjInsArg::Arg(v) => argument::Value::Argument(ArgumentValue::from(v)),
+                ObjInsArg::Arg(v) => argument::Value::Argument(ArgumentValue::new(v)),
                 ObjInsArg::Reloc => argument::Value::Relocation(ArgumentRelocation {}),
                 ObjInsArg::BranchDest(dest) => argument::Value::BranchDest(*dest),
             }),
@@ -152,8 +156,8 @@ impl<'a> From<&'a ObjInsArg> for Argument {
     }
 }
 
-impl From<&ObjInsArgValue> for ArgumentValue {
+impl ArgumentValue {
-    fn from(value: &ObjInsArgValue) -> Self {
+    pub fn new(value: &ObjInsArgValue) -> Self {
         Self {
             value: Some(match value {
                 ObjInsArgValue::Signed(v) => argument_value::Value::Signed(*v),
@@ -164,42 +168,39 @@ impl From<&ObjInsArgValue> for ArgumentValue {
     }
 }
 
-impl<'a> From<&'a ObjReloc> for Relocation {
+impl Relocation {
-    fn from(value: &ObjReloc) -> Self {
+    pub fn new(object: &ObjInfo, reloc: &ObjReloc) -> Self {
         Self {
-            r#type: match value.flags {
+            r#type: match reloc.flags {
                 object::RelocationFlags::Elf { r_type } => r_type,
                 object::RelocationFlags::MachO { r_type, .. } => r_type as u32,
                 object::RelocationFlags::Coff { typ } => typ as u32,
                 object::RelocationFlags::Xcoff { r_rtype, .. } => r_rtype as u32,
                 _ => unreachable!(),
             },
-            type_name: String::new(), // TODO
+            type_name: object.arch.display_reloc(reloc.flags).into_owned(),
-            target: Some(RelocationTarget::from(&value.target)),
+            target: Some(RelocationTarget {
+                symbol: Some(Symbol::new(&reloc.target)),
+                addend: reloc.addend,
+            }),
         }
     }
 }
 
-impl<'a> From<&'a ObjSymbol> for RelocationTarget {
+impl InstructionDiff {
-    fn from(value: &'a ObjSymbol) -> Self {
+    pub fn new(object: &ObjInfo, instruction_diff: &ObjInsDiff) -> Self {
-        Self { symbol: Some(Symbol::from(value)), addend: value.addend }
-    }
-}
-
-impl<'a> From<&'a ObjInsDiff> for InstructionDiff {
-    fn from(value: &'a ObjInsDiff) -> Self {
         Self {
-            instruction: value.ins.as_ref().map(Instruction::from),
+            instruction: instruction_diff.ins.as_ref().map(|ins| Instruction::new(object, ins)),
-            diff_kind: DiffKind::from(value.kind) as i32,
+            diff_kind: DiffKind::from(instruction_diff.kind) as i32,
-            branch_from: value.branch_from.as_ref().map(InstructionBranchFrom::from),
+            branch_from: instruction_diff.branch_from.as_ref().map(InstructionBranchFrom::new),
-            branch_to: value.branch_to.as_ref().map(InstructionBranchTo::from),
+            branch_to: instruction_diff.branch_to.as_ref().map(InstructionBranchTo::new),
-            arg_diff: value.arg_diff.iter().map(ArgumentDiff::from).collect(),
+            arg_diff: instruction_diff.arg_diff.iter().map(ArgumentDiff::new).collect(),
         }
     }
 }
 
-impl From<&Option<ObjInsArgDiff>> for ArgumentDiff {
+impl ArgumentDiff {
-    fn from(value: &Option<ObjInsArgDiff>) -> Self {
+    pub fn new(value: &Option<ObjInsArgDiff>) -> Self {
         Self { diff_index: value.as_ref().map(|v| v.idx as u32) }
     }
 }
@@ -228,8 +229,8 @@ impl From<ObjDataDiffKind> for DiffKind {
     }
 }
 
-impl<'a> From<&'a ObjInsBranchFrom> for InstructionBranchFrom {
+impl InstructionBranchFrom {
-    fn from(value: &'a ObjInsBranchFrom) -> Self {
+    pub fn new(value: &ObjInsBranchFrom) -> Self {
         Self {
             instruction_index: value.ins_idx.iter().map(|&x| x as u32).collect(),
             branch_index: value.branch_idx as u32,
@@ -237,8 +238,8 @@ impl<'a> From<&'a ObjInsBranchFrom> for InstructionBranchFrom {
     }
 }
 
-impl<'a> From<&'a ObjInsBranchTo> for InstructionBranchTo {
+impl InstructionBranchTo {
-    fn from(value: &'a ObjInsBranchTo) -> Self {
+    pub fn new(value: &ObjInsBranchTo) -> Self {
         Self { instruction_index: value.ins_idx as u32, branch_index: value.branch_idx as u32 }
     }
 }

objdiff-core/src/config/mod.rs

@@ -1,77 +1,100 @@
 use std::{
+    fs,
     fs::File,
-    io::{BufReader, Read},
+    io::{BufReader, BufWriter, Read},
     path::{Path, PathBuf},
 };
 
 use anyhow::{anyhow, Context, Result};
+use bimap::BiBTreeMap;
 use filetime::FileTime;
 use globset::{Glob, GlobSet, GlobSetBuilder};
 
-#[inline]
+#[derive(Default, Clone, serde::Serialize, serde::Deserialize)]
-fn bool_true() -> bool { true }
-
-#[derive(Default, Clone, serde::Deserialize)]
 pub struct ProjectConfig {
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub min_version: Option<String>,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub custom_make: Option<String>,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub custom_args: Option<Vec<String>>,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub target_dir: Option<PathBuf>,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub base_dir: Option<PathBuf>,
-    #[serde(default = "bool_true")]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub build_base: bool,
+    pub build_base: Option<bool>,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub build_target: bool,
+    pub build_target: Option<bool>,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub watch_patterns: Option<Vec<Glob>>,
-    #[serde(default, alias = "units")]
+    #[serde(default, alias = "objects", skip_serializing_if = "Option::is_none")]
-    pub objects: Vec<ProjectObject>,
+    pub units: Option<Vec<ProjectObject>>,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub progress_categories: Vec<ProjectProgressCategory>,
+    pub progress_categories: Option<Vec<ProjectProgressCategory>>,
 }
 
-#[derive(Default, Clone, serde::Deserialize)]
+impl ProjectConfig {
+    #[inline]
+    pub fn units(&self) -> &[ProjectObject] { self.units.as_deref().unwrap_or_default() }
+
+    #[inline]
+    pub fn units_mut(&mut self) -> &mut Vec<ProjectObject> {
+        self.units.get_or_insert_with(Vec::new)
+    }
+
+    #[inline]
+    pub fn progress_categories(&self) -> &[ProjectProgressCategory] {
+        self.progress_categories.as_deref().unwrap_or_default()
+    }
+
+    #[inline]
+    pub fn progress_categories_mut(&mut self) -> &mut Vec<ProjectProgressCategory> {
+        self.progress_categories.get_or_insert_with(Vec::new)
+    }
+}
+
+#[derive(Default, Clone, serde::Serialize, serde::Deserialize)]
 pub struct ProjectObject {
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub name: Option<String>,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub path: Option<PathBuf>,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub target_path: Option<PathBuf>,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub base_path: Option<PathBuf>,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     #[deprecated(note = "Use metadata.reverse_fn_order")]
     pub reverse_fn_order: Option<bool>,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     #[deprecated(note = "Use metadata.complete")]
     pub complete: Option<bool>,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub scratch: Option<ScratchConfig>,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub metadata: Option<ProjectObjectMetadata>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub symbol_mappings: Option<SymbolMappings>,
 }
 
-#[derive(Default, Clone, serde::Deserialize)]
+pub type SymbolMappings = BiBTreeMap<String, String>;
+
+#[derive(Default, Clone, serde::Serialize, serde::Deserialize)]
 pub struct ProjectObjectMetadata {
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub complete: Option<bool>,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub reverse_fn_order: Option<bool>,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub source_path: Option<String>,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub progress_categories: Option<Vec<String>>,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub auto_generated: Option<bool>,
 }
 
-#[derive(Default, Clone, serde::Deserialize)]
+#[derive(Default, Clone, serde::Serialize, serde::Deserialize)]
 pub struct ProjectProgressCategory {
     #[serde(default)]
     pub id: String,
@@ -112,12 +135,12 @@ impl ProjectObject {
     }
 
     pub fn complete(&self) -> Option<bool> {
-        #[allow(deprecated)]
+        #[expect(deprecated)]
         self.metadata.as_ref().and_then(|m| m.complete).or(self.complete)
     }
 
     pub fn reverse_fn_order(&self) -> Option<bool> {
-        #[allow(deprecated)]
+        #[expect(deprecated)]
         self.metadata.as_ref().and_then(|m| m.reverse_fn_order).or(self.reverse_fn_order)
     }
 
@@ -132,16 +155,16 @@ impl ProjectObject {
 
 #[derive(Default, Clone, Eq, PartialEq, serde::Deserialize, serde::Serialize)]
 pub struct ScratchConfig {
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub platform: Option<String>,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub compiler: Option<String>,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub c_flags: Option<String>,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
     pub ctx_path: Option<PathBuf>,
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub build_ctx: bool,
+    pub build_ctx: Option<bool>,
 }
 
 pub const CONFIG_FILENAMES: [&str; 3] = ["objdiff.json", "objdiff.yml", "objdiff.yaml"];
@@ -154,7 +177,7 @@ pub const DEFAULT_WATCH_PATTERNS: &[&str] = &[
 #[derive(Clone, Eq, PartialEq)]
 pub struct ProjectConfigInfo {
     pub path: PathBuf,
-    pub timestamp: FileTime,
+    pub timestamp: Option<FileTime>,
 }
 
 pub fn try_project_config(dir: &Path) -> Option<(Result<ProjectConfig>, ProjectConfigInfo)> {
@@ -180,12 +203,41 @@ pub fn try_project_config(dir: &Path) -> Option<(Result<ProjectConfig>, ProjectC
                     result = Err(e);
                 }
             }
-            return Some((result, ProjectConfigInfo { path: config_path, timestamp: ts }));
+            return Some((result, ProjectConfigInfo { path: config_path, timestamp: Some(ts) }));
         }
     }
     None
 }
 
+pub fn save_project_config(
+    config: &ProjectConfig,
+    info: &ProjectConfigInfo,
+) -> Result<ProjectConfigInfo> {
+    if let Some(last_ts) = info.timestamp {
+        // Check if the file has changed since we last read it
+        if let Ok(metadata) = fs::metadata(&info.path) {
+            let ts = FileTime::from_last_modification_time(&metadata);
+            if ts != last_ts {
+                return Err(anyhow!("Config file has changed since last read"));
+            }
+        }
+    }
+    let mut writer =
+        BufWriter::new(File::create(&info.path).context("Failed to create config file")?);
+    let ext = info.path.extension().and_then(|ext| ext.to_str()).unwrap_or("json");
+    match ext {
+        "json" => serde_json::to_writer_pretty(&mut writer, config).context("Failed to write JSON"),
+        "yml" | "yaml" => {
+            serde_yaml::to_writer(&mut writer, config).context("Failed to write YAML")
+        }
+        _ => Err(anyhow!("Unknown config file extension: {ext}")),
+    }?;
+    let file = writer.into_inner().context("Failed to flush file")?;
+    let metadata = file.metadata().context("Failed to get file metadata")?;
+    let ts = FileTime::from_last_modification_time(&metadata);
+    Ok(ProjectConfigInfo { path: info.path.clone(), timestamp: Some(ts) })
+}
+
 fn validate_min_version(config: &ProjectConfig) -> Result<()> {
     let Some(min_version) = &config.min_version else { return Ok(()) };
     let version = semver::Version::parse(env!("CARGO_PKG_VERSION"))

objdiff-core/src/diff/code.rs

@@ -9,7 +9,7 @@ use crate::{
         DiffObjConfig, ObjInsArgDiff, ObjInsBranchFrom, ObjInsBranchTo, ObjInsDiff, ObjInsDiffKind,
         ObjSymbolDiff,
     },
-    obj::{ObjInfo, ObjInsArg, ObjReloc, ObjSymbol, ObjSymbolFlags, SymbolRef},
+    obj::{ObjInfo, ObjInsArg, ObjReloc, ObjSymbolFlags, SymbolRef},
 };
 
 pub fn process_code_symbol(
@@ -41,10 +41,12 @@ pub fn no_diff_code(out: &ProcessCodeResult, symbol_ref: SymbolRef) -> Result<Ob
         });
     }
     resolve_branches(&mut diff);
-    Ok(ObjSymbolDiff { symbol_ref, diff_symbol: None, instructions: diff, match_percent: None })
+    Ok(ObjSymbolDiff { symbol_ref, target_symbol: None, instructions: diff, match_percent: None })
 }
 
 pub fn diff_code(
+    left_obj: &ObjInfo,
+    right_obj: &ObjInfo,
     left_out: &ProcessCodeResult,
     right_out: &ProcessCodeResult,
     left_symbol_ref: SymbolRef,
@@ -60,14 +62,14 @@ pub fn diff_code(
 
     let mut diff_state = InsDiffState::default();
     for (left, right) in left_diff.iter_mut().zip(right_diff.iter_mut()) {
-        let result = compare_ins(config, left, right, &mut diff_state)?;
+        let result = compare_ins(config, left_obj, right_obj, left, right, &mut diff_state)?;
         left.kind = result.kind;
         right.kind = result.kind;
         left.arg_diff = result.left_args_diff;
         right.arg_diff = result.right_args_diff;
     }
 
-    let total = left_out.insts.len();
+    let total = left_out.insts.len().max(right_out.insts.len());
     let percent = if diff_state.diff_count >= total {
         0.0
     } else {
@@ -77,13 +79,13 @@ pub fn diff_code(
     Ok((
         ObjSymbolDiff {
             symbol_ref: left_symbol_ref,
-            diff_symbol: Some(right_symbol_ref),
+            target_symbol: Some(right_symbol_ref),
             instructions: left_diff,
             match_percent: Some(percent),
         },
         ObjSymbolDiff {
             symbol_ref: right_symbol_ref,
-            diff_symbol: Some(left_symbol_ref),
+            target_symbol: Some(left_symbol_ref),
             instructions: right_diff,
             match_percent: Some(percent),
         },
@@ -170,12 +172,33 @@ fn resolve_branches(vec: &mut [ObjInsDiff]) {
     }
 }
 
-fn address_eq(left: &ObjSymbol, right: &ObjSymbol) -> bool {
+fn address_eq(left: &ObjReloc, right: &ObjReloc) -> bool {
-    left.address as i64 + left.addend == right.address as i64 + right.addend
+    left.target.address as i64 + left.addend == right.target.address as i64 + right.addend
+}
+
+fn section_name_eq(
+    left_obj: &ObjInfo,
+    right_obj: &ObjInfo,
+    left_orig_section_index: usize,
+    right_orig_section_index: usize,
+) -> bool {
+    let Some(left_section) =
+        left_obj.sections.iter().find(|s| s.orig_index == left_orig_section_index)
+    else {
+        return false;
+    };
+    let Some(right_section) =
+        right_obj.sections.iter().find(|s| s.orig_index == right_orig_section_index)
+    else {
+        return false;
+    };
+    left_section.name == right_section.name
 }
 
 fn reloc_eq(
     config: &DiffObjConfig,
+    left_obj: &ObjInfo,
+    right_obj: &ObjInfo,
     left_reloc: Option<&ObjReloc>,
     right_reloc: Option<&ObjReloc>,
 ) -> bool {
@@ -189,29 +212,32 @@ fn reloc_eq(
         return true;
     }
 
-    let name_matches = left.target.name == right.target.name;
+    let symbol_name_matches = left.target.name == right.target.name;
-    match (&left.target_section, &right.target_section) {
+    match (&left.target.orig_section_index, &right.target.orig_section_index) {
         (Some(sl), Some(sr)) => {
             // Match if section and name or address match
-            sl == sr && (name_matches || address_eq(&left.target, &right.target))
+            section_name_eq(left_obj, right_obj, *sl, *sr)
+                && (symbol_name_matches || address_eq(left, right))
         }
         (Some(_), None) => false,
         (None, Some(_)) => {
             // Match if possibly stripped weak symbol
-            name_matches && right.target.flags.0.contains(ObjSymbolFlags::Weak)
+            symbol_name_matches && right.target.flags.0.contains(ObjSymbolFlags::Weak)
         }
-        (None, None) => name_matches,
+        (None, None) => symbol_name_matches,
     }
 }
 
 fn arg_eq(
     config: &DiffObjConfig,
+    left_obj: &ObjInfo,
+    right_obj: &ObjInfo,
     left: &ObjInsArg,
     right: &ObjInsArg,
     left_diff: &ObjInsDiff,
     right_diff: &ObjInsDiff,
 ) -> bool {
-    return match left {
+    match left {
         ObjInsArg::PlainText(l) => match right {
             ObjInsArg::PlainText(r) => l == r,
             _ => false,
@@ -227,6 +253,8 @@ fn arg_eq(
             matches!(right, ObjInsArg::Reloc)
                 && reloc_eq(
                     config,
+                    left_obj,
+                    right_obj,
                     left_diff.ins.as_ref().and_then(|i| i.reloc.as_ref()),
                     right_diff.ins.as_ref().and_then(|i| i.reloc.as_ref()),
                 )
@@ -236,7 +264,7 @@ fn arg_eq(
             left_diff.branch_to.as_ref().map(|b| b.ins_idx)
                 == right_diff.branch_to.as_ref().map(|b| b.ins_idx)
         }
-    };
+    }
 }
 
 #[derive(Default)]
@@ -257,6 +285,8 @@ struct InsDiffResult {
 
 fn compare_ins(
     config: &DiffObjConfig,
+    left_obj: &ObjInfo,
+    right_obj: &ObjInfo,
     left: &ObjInsDiff,
     right: &ObjInsDiff,
     state: &mut InsDiffState,
@@ -283,7 +313,7 @@ fn compare_ins(
             state.diff_count += 1;
         }
         for (a, b) in left_ins.args.iter().zip(&right_ins.args) {
-            if arg_eq(config, a, b, left, right) {
+            if arg_eq(config, left_obj, right_obj, a, b, left, right) {
                 result.left_args_diff.push(None);
                 result.right_args_diff.push(None);
             } else {

objdiff-core/src/diff/data.rs

@@ -20,13 +20,13 @@ pub fn diff_bss_symbol(
     Ok((
         ObjSymbolDiff {
             symbol_ref: left_symbol_ref,
-            diff_symbol: Some(right_symbol_ref),
+            target_symbol: Some(right_symbol_ref),
             instructions: vec![],
             match_percent: Some(percent),
         },
         ObjSymbolDiff {
             symbol_ref: right_symbol_ref,
-            diff_symbol: Some(left_symbol_ref),
+            target_symbol: Some(left_symbol_ref),
             instructions: vec![],
             match_percent: Some(percent),
         },
@@ -34,7 +34,7 @@ pub fn diff_bss_symbol(
 }
 
 pub fn no_diff_symbol(_obj: &ObjInfo, symbol_ref: SymbolRef) -> ObjSymbolDiff {
-    ObjSymbolDiff { symbol_ref, diff_symbol: None, instructions: vec![], match_percent: None }
+    ObjSymbolDiff { symbol_ref, target_symbol: None, instructions: vec![], match_percent: None }
 }
 
 /// Compare the data sections of two object files.
@@ -158,13 +158,13 @@ pub fn diff_data_symbol(
     Ok((
         ObjSymbolDiff {
             symbol_ref: left_symbol_ref,
-            diff_symbol: Some(right_symbol_ref),
+            target_symbol: Some(right_symbol_ref),
             instructions: vec![],
             match_percent: Some(match_percent),
         },
         ObjSymbolDiff {
             symbol_ref: right_symbol_ref,
-            diff_symbol: Some(left_symbol_ref),
+            target_symbol: Some(left_symbol_ref),
             instructions: vec![],
             match_percent: Some(match_percent),
         },

objdiff-core/src/diff/display.rs

@@ -29,7 +29,7 @@ pub enum DiffText<'a> {
     Eol,
 }
 
-#[derive(Default, Clone, PartialEq, Eq)]
+#[derive(Debug, Default, Clone, PartialEq, Eq)]
 pub enum HighlightKind {
     #[default]
     None,
@@ -94,9 +94,9 @@ fn display_reloc_name<E>(
     mut cb: impl FnMut(DiffText) -> Result<(), E>,
 ) -> Result<(), E> {
     cb(DiffText::Symbol(&reloc.target))?;
-    match reloc.target.addend.cmp(&0i64) {
+    match reloc.addend.cmp(&0i64) {
-        Ordering::Greater => cb(DiffText::Basic(&format!("+{:#x}", reloc.target.addend))),
+        Ordering::Greater => cb(DiffText::Basic(&format!("+{:#x}", reloc.addend))),
-        Ordering::Less => cb(DiffText::Basic(&format!("-{:#x}", -reloc.target.addend))),
+        Ordering::Less => cb(DiffText::Basic(&format!("-{:#x}", -reloc.addend))),
         _ => Ok(()),
     }
 }

objdiff-core/src/diff/mod.rs

@@ -3,6 +3,7 @@ use std::collections::HashSet;
 use anyhow::Result;
 
 use crate::{
+    config::SymbolMappings,
     diff::{
         code::{diff_code, no_diff_code, process_code_symbol},
         data::{
@@ -10,7 +11,7 @@ use crate::{
             diff_generic_section, no_diff_symbol,
         },
     },
-    obj::{ObjInfo, ObjIns, ObjSection, ObjSectionKind, ObjSymbol, SymbolRef},
+    obj::{ObjInfo, ObjIns, ObjSection, ObjSectionKind, ObjSymbol, SymbolRef, SECTION_COMMON},
 };
 
 pub mod code;
@@ -28,8 +29,8 @@ pub mod display;
     serde::Serialize,
     strum::VariantArray,
     strum::EnumMessage,
-    tsify_next::Tsify,
 )]
+#[cfg_attr(feature = "wasm", derive(tsify_next::Tsify))]
 pub enum X86Formatter {
     #[default]
     #[strum(message = "Intel (default)")]
@@ -53,8 +54,8 @@ pub enum X86Formatter {
     serde::Serialize,
     strum::VariantArray,
     strum::EnumMessage,
-    tsify_next::Tsify,
 )]
+#[cfg_attr(feature = "wasm", derive(tsify_next::Tsify))]
 pub enum MipsAbi {
     #[default]
     #[strum(message = "Auto (default)")]
@@ -78,8 +79,8 @@ pub enum MipsAbi {
     serde::Serialize,
     strum::VariantArray,
     strum::EnumMessage,
-    tsify_next::Tsify,
 )]
+#[cfg_attr(feature = "wasm", derive(tsify_next::Tsify))]
 pub enum MipsInstrCategory {
     #[default]
     #[strum(message = "Auto (default)")]
@@ -107,8 +108,8 @@ pub enum MipsInstrCategory {
     serde::Serialize,
     strum::VariantArray,
     strum::EnumMessage,
-    tsify_next::Tsify,
 )]
+#[cfg_attr(feature = "wasm", derive(tsify_next::Tsify))]
 pub enum ArmArchVersion {
     #[default]
     #[strum(message = "Auto (default)")]
@@ -132,8 +133,8 @@ pub enum ArmArchVersion {
     serde::Serialize,
     strum::VariantArray,
     strum::EnumMessage,
-    tsify_next::Tsify,
 )]
+#[cfg_attr(feature = "wasm", derive(tsify_next::Tsify))]
 pub enum ArmR9Usage {
     #[default]
     #[strum(
@@ -153,14 +154,17 @@ pub enum ArmR9Usage {
 #[inline]
 const fn default_true() -> bool { true }
 
-#[derive(Debug, Clone, Eq, PartialEq, serde::Deserialize, serde::Serialize, tsify_next::Tsify)]
+#[derive(Debug, Clone, Eq, PartialEq, serde::Deserialize, serde::Serialize)]
-#[tsify(from_wasm_abi)]
+#[cfg_attr(feature = "wasm", derive(tsify_next::Tsify))]
+#[cfg_attr(feature = "wasm", tsify(from_wasm_abi))]
 #[serde(default)]
 pub struct DiffObjConfig {
     pub relax_reloc_diffs: bool,
     #[serde(default = "default_true")]
     pub space_between_args: bool,
     pub combine_data_sections: bool,
+    #[serde(default)]
+    pub symbol_mappings: MappingConfig,
     // x86
     pub x86_formatter: X86Formatter,
     // MIPS
@@ -182,6 +186,7 @@ impl Default for DiffObjConfig {
             relax_reloc_diffs: false,
             space_between_args: true,
             combine_data_sections: false,
+            symbol_mappings: Default::default(),
             x86_formatter: Default::default(),
             mips_abi: Default::default(),
             mips_instr_category: Default::default(),
@@ -223,8 +228,10 @@ impl ObjSectionDiff {
 
 #[derive(Debug, Clone, Default)]
 pub struct ObjSymbolDiff {
+    /// The symbol ref this object
     pub symbol_ref: SymbolRef,
-    pub diff_symbol: Option<SymbolRef>,
+    /// The symbol ref in the _other_ object that this symbol was diffed against
+    pub target_symbol: Option<SymbolRef>,
     pub instructions: Vec<ObjInsDiff>,
     pub match_percent: Option<f32>,
 }
@@ -294,8 +301,13 @@ pub struct ObjInsBranchTo {
 
 #[derive(Default)]
 pub struct ObjDiff {
+    /// A list of all section diffs in the object.
     pub sections: Vec<ObjSectionDiff>,
+    /// Common BSS symbols don't live in a section, so they're stored separately.
     pub common: Vec<ObjSymbolDiff>,
+    /// If `selecting_left` or `selecting_right` is set, this is the list of symbols
+    /// that are being mapped to the other object.
+    pub mapping_symbols: Vec<ObjSymbolDiff>,
 }
 
 impl ObjDiff {
@@ -303,13 +315,14 @@ impl ObjDiff {
         let mut result = Self {
             sections: Vec::with_capacity(obj.sections.len()),
             common: Vec::with_capacity(obj.common.len()),
+            mapping_symbols: vec![],
         };
         for (section_idx, section) in obj.sections.iter().enumerate() {
             let mut symbols = Vec::with_capacity(section.symbols.len());
             for (symbol_idx, _) in section.symbols.iter().enumerate() {
                 symbols.push(ObjSymbolDiff {
                     symbol_ref: SymbolRef { section_idx, symbol_idx },
-                    diff_symbol: None,
+                    target_symbol: None,
                     instructions: vec![],
                     match_percent: None,
                 });
@@ -327,8 +340,8 @@ impl ObjDiff {
         }
         for (symbol_idx, _) in obj.common.iter().enumerate() {
             result.common.push(ObjSymbolDiff {
-                symbol_ref: SymbolRef { section_idx: obj.sections.len(), symbol_idx },
+                symbol_ref: SymbolRef { section_idx: SECTION_COMMON, symbol_idx },
-                diff_symbol: None,
+                target_symbol: None,
                 instructions: vec![],
                 match_percent: None,
             });
@@ -348,7 +361,7 @@ impl ObjDiff {
 
     #[inline]
     pub fn symbol_diff(&self, symbol_ref: SymbolRef) -> &ObjSymbolDiff {
-        if symbol_ref.section_idx == self.sections.len() {
+        if symbol_ref.section_idx == SECTION_COMMON {
             &self.common[symbol_ref.symbol_idx]
         } else {
             &self.section_diff(symbol_ref.section_idx).symbols[symbol_ref.symbol_idx]
@@ -357,7 +370,7 @@ impl ObjDiff {
 
     #[inline]
     pub fn symbol_diff_mut(&mut self, symbol_ref: SymbolRef) -> &mut ObjSymbolDiff {
-        if symbol_ref.section_idx == self.sections.len() {
+        if symbol_ref.section_idx == SECTION_COMMON {
             &mut self.common[symbol_ref.symbol_idx]
         } else {
             &mut self.section_diff_mut(symbol_ref.section_idx).symbols[symbol_ref.symbol_idx]
@@ -378,7 +391,7 @@ pub fn diff_objs(
     right: Option<&ObjInfo>,
     prev: Option<&ObjInfo>,
 ) -> Result<DiffObjsResult> {
-    let symbol_matches = matching_symbols(left, right, prev)?;
+    let symbol_matches = matching_symbols(left, right, prev, &config.symbol_mappings)?;
     let section_matches = matching_sections(left, right)?;
     let mut left = left.map(|p| (p, ObjDiff::new_from_obj(p)));
     let mut right = right.map(|p| (p, ObjDiff::new_from_obj(p)));
@@ -399,6 +412,8 @@ pub fn diff_objs(
                         let left_code = process_code_symbol(left_obj, left_symbol_ref, config)?;
                         let right_code = process_code_symbol(right_obj, right_symbol_ref, config)?;
                         let (left_diff, right_diff) = diff_code(
+                            left_obj,
+                            right_obj,
                             &left_code,
                             &right_code,
                             left_symbol_ref,
@@ -412,6 +427,8 @@ pub fn diff_objs(
                             let (prev_obj, prev_out) = prev.as_mut().unwrap();
                             let prev_code = process_code_symbol(prev_obj, prev_symbol_ref, config)?;
                             let (_, prev_diff) = diff_code(
+                                left_obj,
+                                right_obj,
                                 &right_code,
                                 &prev_code,
                                 right_symbol_ref,
@@ -529,6 +546,17 @@ pub fn diff_objs(
         }
     }
 
+    if let (Some((right_obj, right_out)), Some((left_obj, left_out))) =
+        (right.as_mut(), left.as_mut())
+    {
+        if let Some(right_name) = &config.symbol_mappings.selecting_left {
+            generate_mapping_symbols(right_obj, right_name, left_obj, left_out, config)?;
+        }
+        if let Some(left_name) = &config.symbol_mappings.selecting_right {
+            generate_mapping_symbols(left_obj, left_name, right_obj, right_out, config)?;
+        }
+    }
+
     Ok(DiffObjsResult {
         left: left.map(|(_, o)| o),
         right: right.map(|(_, o)| o),
@@ -536,6 +564,65 @@ pub fn diff_objs(
     })
 }
 
+/// When we're selecting a symbol to use as a comparison, we'll create comparisons for all
+/// symbols in the other object that match the selected symbol's section and kind. This allows
+/// us to display match percentages for all symbols in the other object that could be selected.
+fn generate_mapping_symbols(
+    base_obj: &ObjInfo,
+    base_name: &str,
+    target_obj: &ObjInfo,
+    target_out: &mut ObjDiff,
+    config: &DiffObjConfig,
+) -> Result<()> {
+    let Some(base_symbol_ref) = symbol_ref_by_name(base_obj, base_name) else {
+        return Ok(());
+    };
+    let (base_section, base_symbol) = base_obj.section_symbol(base_symbol_ref);
+    let Some(base_section) = base_section else {
+        return Ok(());
+    };
+    let base_code = match base_section.kind {
+        ObjSectionKind::Code => Some(process_code_symbol(base_obj, base_symbol_ref, config)?),
+        _ => None,
+    };
+    for (target_section_index, target_section) in
+        target_obj.sections.iter().enumerate().filter(|(_, s)| s.kind == base_section.kind)
+    {
+        for (target_symbol_index, _target_symbol) in
+            target_section.symbols.iter().enumerate().filter(|(_, s)| s.kind == base_symbol.kind)
+        {
+            let target_symbol_ref =
+                SymbolRef { section_idx: target_section_index, symbol_idx: target_symbol_index };
+            match base_section.kind {
+                ObjSectionKind::Code => {
+                    let target_code = process_code_symbol(target_obj, target_symbol_ref, config)?;
+                    let (left_diff, _right_diff) = diff_code(
+                        target_obj,
+                        base_obj,
+                        &target_code,
+                        base_code.as_ref().unwrap(),
+                        target_symbol_ref,
+                        base_symbol_ref,
+                        config,
+                    )?;
+                    target_out.mapping_symbols.push(left_diff);
+                }
+                ObjSectionKind::Data => {
+                    let (left_diff, _right_diff) =
+                        diff_data_symbol(target_obj, base_obj, target_symbol_ref, base_symbol_ref)?;
+                    target_out.mapping_symbols.push(left_diff);
+                }
+                ObjSectionKind::Bss => {
+                    let (left_diff, _right_diff) =
+                        diff_bss_symbol(target_obj, base_obj, target_symbol_ref, base_symbol_ref)?;
+                    target_out.mapping_symbols.push(left_diff);
+                }
+            }
+        }
+    }
+    Ok(())
+}
+
 #[derive(Copy, Clone, Eq, PartialEq)]
 struct SymbolMatch {
     left: Option<SymbolRef>,
@@ -551,19 +638,115 @@ struct SectionMatch {
     section_kind: ObjSectionKind,
 }
 
+#[derive(Debug, Clone, PartialEq, Eq, Hash, Default, serde::Deserialize, serde::Serialize)]
+pub struct MappingConfig {
+    /// Manual symbol mappings
+    pub mappings: SymbolMappings,
+    /// The right object symbol name that we're selecting a left symbol for
+    pub selecting_left: Option<String>,
+    /// The left object symbol name that we're selecting a right symbol for
+    pub selecting_right: Option<String>,
+}
+
+fn symbol_ref_by_name(obj: &ObjInfo, name: &str) -> Option<SymbolRef> {
+    for (section_idx, section) in obj.sections.iter().enumerate() {
+        for (symbol_idx, symbol) in section.symbols.iter().enumerate() {
+            if symbol.name == name {
+                return Some(SymbolRef { section_idx, symbol_idx });
+            }
+        }
+    }
+    None
+}
+
+fn apply_symbol_mappings(
+    left: &ObjInfo,
+    right: &ObjInfo,
+    mapping_config: &MappingConfig,
+    left_used: &mut HashSet<SymbolRef>,
+    right_used: &mut HashSet<SymbolRef>,
+    matches: &mut Vec<SymbolMatch>,
+) -> Result<()> {
+    // If we're selecting a symbol to use as a comparison, mark it as used
+    // This ensures that we don't match it to another symbol at any point
+    if let Some(left_name) = &mapping_config.selecting_left {
+        if let Some(left_symbol) = symbol_ref_by_name(left, left_name) {
+            left_used.insert(left_symbol);
+        }
+    }
+    if let Some(right_name) = &mapping_config.selecting_right {
+        if let Some(right_symbol) = symbol_ref_by_name(right, right_name) {
+            right_used.insert(right_symbol);
+        }
+    }
+
+    // Apply manual symbol mappings
+    for (left_name, right_name) in &mapping_config.mappings {
+        let Some(left_symbol) = symbol_ref_by_name(left, left_name) else {
+            continue;
+        };
+        if left_used.contains(&left_symbol) {
+            continue;
+        }
+        let Some(right_symbol) = symbol_ref_by_name(right, right_name) else {
+            continue;
+        };
+        if right_used.contains(&right_symbol) {
+            continue;
+        }
+        let left_section = &left.sections[left_symbol.section_idx];
+        let right_section = &right.sections[right_symbol.section_idx];
+        if left_section.kind != right_section.kind {
+            log::warn!(
+                "Symbol section kind mismatch: {} ({:?}) vs {} ({:?})",
+                left_name,
+                left_section.kind,
+                right_name,
+                right_section.kind
+            );
+            continue;
+        }
+        matches.push(SymbolMatch {
+            left: Some(left_symbol),
+            right: Some(right_symbol),
+            prev: None, // TODO
+            section_kind: left_section.kind,
+        });
+        left_used.insert(left_symbol);
+        right_used.insert(right_symbol);
+    }
+    Ok(())
+}
+
 /// Find matching symbols between each object.
 fn matching_symbols(
     left: Option<&ObjInfo>,
     right: Option<&ObjInfo>,
     prev: Option<&ObjInfo>,
+    mappings: &MappingConfig,
 ) -> Result<Vec<SymbolMatch>> {
     let mut matches = Vec::new();
+    let mut left_used = HashSet::new();
     let mut right_used = HashSet::new();
     if let Some(left) = left {
+        if let Some(right) = right {
+            apply_symbol_mappings(
+                left,
+                right,
+                mappings,
+                &mut left_used,
+                &mut right_used,
+                &mut matches,
+            )?;
+        }
         for (section_idx, section) in left.sections.iter().enumerate() {
             for (symbol_idx, symbol) in section.symbols.iter().enumerate() {
+                let symbol_ref = SymbolRef { section_idx, symbol_idx };
+                if left_used.contains(&symbol_ref) {
+                    continue;
+                }
                 let symbol_match = SymbolMatch {
-                    left: Some(SymbolRef { section_idx, symbol_idx }),
+                    left: Some(symbol_ref),
                     right: find_symbol(right, symbol, section, Some(&right_used)),
                     prev: find_symbol(prev, symbol, section, None),
                     section_kind: section.kind,
@@ -575,8 +758,12 @@ fn matching_symbols(
             }
         }
         for (symbol_idx, symbol) in left.common.iter().enumerate() {
+            let symbol_ref = SymbolRef { section_idx: SECTION_COMMON, symbol_idx };
+            if left_used.contains(&symbol_ref) {
+                continue;
+            }
             let symbol_match = SymbolMatch {
-                left: Some(SymbolRef { section_idx: left.sections.len(), symbol_idx }),
+                left: Some(symbol_ref),
                 right: find_common_symbol(right, symbol),
                 prev: find_common_symbol(prev, symbol),
                 section_kind: ObjSectionKind::Bss,
@@ -603,7 +790,7 @@ fn matching_symbols(
             }
         }
         for (symbol_idx, symbol) in right.common.iter().enumerate() {
-            let symbol_ref = SymbolRef { section_idx: right.sections.len(), symbol_idx };
+            let symbol_ref = SymbolRef { section_idx: SECTION_COMMON, symbol_idx };
             if right_used.contains(&symbol_ref) {
                 continue;
             }
@@ -696,7 +883,7 @@ fn find_common_symbol(obj: Option<&ObjInfo>, in_symbol: &ObjSymbol) -> Option<Sy
     let obj = obj?;
     for (symbol_idx, symbol) in obj.common.iter().enumerate() {
         if symbol.name == in_symbol.name {
-            return Some(SymbolRef { section_idx: obj.sections.len(), symbol_idx });
+            return Some(SymbolRef { section_idx: SECTION_COMMON, symbol_idx });
         }
     }
     None

objdiff-core/src/lib.rs

@@ -8,4 +8,5 @@ pub mod config;
 pub mod diff;
 #[cfg(feature = "any-arch")]
 pub mod obj;
+#[cfg(feature = "any-arch")]
 pub mod util;

objdiff-core/src/obj/mod.rs

@@ -112,6 +112,15 @@ pub struct ObjIns {
     pub orig: Option<String>,
 }
 
+#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash, Default)]
+pub enum ObjSymbolKind {
+    #[default]
+    Unknown,
+    Function,
+    Object,
+    Section,
+}
+
 #[derive(Debug, Clone)]
 pub struct ObjSymbol {
     pub name: String,
@@ -120,8 +129,9 @@ pub struct ObjSymbol {
     pub section_address: u64,
     pub size: u64,
     pub size_known: bool,
+    pub kind: ObjSymbolKind,
     pub flags: ObjSymbolFlagSet,
-    pub addend: i64,
+    pub orig_section_index: Option<usize>,
     /// Original virtual address (from .note.split section)
     pub virtual_address: Option<u64>,
     /// Original index in object symbol table
@@ -145,7 +155,7 @@ pub struct ObjReloc {
     pub flags: RelocationFlags,
     pub address: u64,
     pub target: ObjSymbol,
-    pub target_section: Option<String>,
+    pub addend: i64,
 }
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Default)]
@@ -154,9 +164,11 @@ pub struct SymbolRef {
     pub symbol_idx: usize,
 }
 
+pub const SECTION_COMMON: usize = usize::MAX - 1;
+
 impl ObjInfo {
     pub fn section_symbol(&self, symbol_ref: SymbolRef) -> (Option<&ObjSection>, &ObjSymbol) {
-        if symbol_ref.section_idx == self.sections.len() {
+        if symbol_ref.section_idx == SECTION_COMMON {
             let symbol = &self.common[symbol_ref.symbol_idx];
             return (None, symbol);
         }

objdiff-core/src/obj/read.rs

@@ -13,8 +13,8 @@ use object::{
     endian::LittleEndian as LE,
     pe::{ImageAuxSymbolFunctionBeginEnd, ImageLinenumber},
     read::coff::{CoffFile, CoffHeader, ImageSymbol},
-    BinaryFormat, File, Object, ObjectSection, ObjectSymbol, RelocationTarget, SectionIndex,
+    BinaryFormat, File, Object, ObjectSection, ObjectSymbol, RelocationTarget, Section,
-    SectionKind, Symbol, SymbolIndex, SymbolKind, SymbolScope, SymbolSection,
+    SectionIndex, SectionKind, Symbol, SymbolIndex, SymbolKind, SymbolScope,
 };
 
 use crate::{
@@ -23,6 +23,7 @@ use crate::{
     obj::{
         split_meta::{SplitMeta, SPLITMETA_SECTION},
         ObjInfo, ObjReloc, ObjSection, ObjSectionKind, ObjSymbol, ObjSymbolFlagSet, ObjSymbolFlags,
+        ObjSymbolKind,
     },
     util::{read_u16, read_u32},
 };
@@ -40,7 +41,6 @@ fn to_obj_symbol(
     arch: &dyn ObjArch,
     obj_file: &File<'_>,
     symbol: &Symbol<'_, '_>,
-    addend: i64,
     split_meta: Option<&SplitMeta>,
 ) -> Result<ObjSymbol> {
     let mut name = symbol.name().context("Failed to process symbol name")?;
@@ -64,6 +64,7 @@ fn to_obj_symbol(
     if obj_file.format() == BinaryFormat::Elf && symbol.scope() == SymbolScope::Linkage {
         flags = ObjSymbolFlagSet(flags.0 | ObjSymbolFlags::Hidden);
     }
+    #[cfg(feature = "ppc")]
     if arch
         .ppc()
         .and_then(|a| a.extab.as_ref())
@@ -94,6 +95,13 @@ fn to_obj_symbol(
         })
         .unwrap_or(&[]);
 
+    let kind = match symbol.kind() {
+        SymbolKind::Text => ObjSymbolKind::Function,
+        SymbolKind::Data => ObjSymbolKind::Object,
+        SymbolKind::Section => ObjSymbolKind::Section,
+        _ => ObjSymbolKind::Unknown,
+    };
+
     Ok(ObjSymbol {
         name: name.to_string(),
         demangled_name,
@@ -101,8 +109,9 @@ fn to_obj_symbol(
         section_address,
         size: symbol.size(),
         size_known: symbol.size() != 0,
+        kind,
         flags,
-        addend,
+        orig_section_index: symbol.section_index().map(|i| i.0),
         virtual_address,
         original_index: Some(symbol.index().0),
         bytes: bytes.to_vec(),
@@ -152,16 +161,15 @@ fn symbols_by_section(
     arch: &dyn ObjArch,
     obj_file: &File<'_>,
     section: &ObjSection,
+    section_symbols: &[Symbol<'_, '_>],
     split_meta: Option<&SplitMeta>,
     name_counts: &mut HashMap<String, u32>,
 ) -> Result<Vec<ObjSymbol>> {
     let mut result = Vec::<ObjSymbol>::new();
-    for symbol in obj_file.symbols() {
+    for symbol in section_symbols {
         if symbol.kind() == SymbolKind::Section {
             continue;
         }
-        if let Some(index) = symbol.section().index() {
-            if index.0 == section.orig_index {
         if symbol.is_local() && section.kind == ObjSectionKind::Code {
             // TODO strip local syms in diff?
             let name = symbol.name().context("Failed to process symbol name")?;
@@ -169,9 +177,7 @@ fn symbols_by_section(
                 continue;
             }
         }
-                result.push(to_obj_symbol(arch, obj_file, &symbol, 0, split_meta)?);
+        result.push(to_obj_symbol(arch, obj_file, symbol, split_meta)?);
-            }
-        }
     }
     result.sort_by(|a, b| a.address.cmp(&b.address).then(a.size.cmp(&b.size)));
     let mut iter = result.iter_mut().peekable();
@@ -182,6 +188,13 @@ fn symbols_by_section(
             } else {
                 symbol.size = (section.address + section.size) - symbol.address;
             }
+            // Set symbol kind if we ended up with a non-zero size
+            if symbol.kind == ObjSymbolKind::Unknown && symbol.size > 0 {
+                symbol.kind = match section.kind {
+                    ObjSectionKind::Code => ObjSymbolKind::Function,
+                    ObjSectionKind::Data | ObjSectionKind::Bss => ObjSymbolKind::Object,
+                };
+            }
         }
     }
     if result.is_empty() {
@@ -199,8 +212,12 @@ fn symbols_by_section(
             section_address: 0,
             size: section.size,
             size_known: true,
+            kind: match section.kind {
+                ObjSectionKind::Code => ObjSymbolKind::Function,
+                ObjSectionKind::Data | ObjSectionKind::Bss => ObjSymbolKind::Object,
+            },
             flags: Default::default(),
-            addend: 0,
+            orig_section_index: Some(section.orig_index),
             virtual_address: None,
             original_index: None,
             bytes: Vec::new(),
@@ -217,51 +234,75 @@ fn common_symbols(
     obj_file
         .symbols()
         .filter(Symbol::is_common)
-        .map(|symbol| to_obj_symbol(arch, obj_file, &symbol, 0, split_meta))
+        .map(|symbol| to_obj_symbol(arch, obj_file, &symbol, split_meta))
         .collect::<Result<Vec<ObjSymbol>>>()
 }
 
+const LOW_PRIORITY_SYMBOLS: &[&str] =
+    &["__gnu_compiled_c", "__gnu_compiled_cplusplus", "gcc2_compiled."];
+
+fn best_symbol<'r, 'data, 'file>(
+    symbols: &'r [Symbol<'data, 'file>],
+    address: u64,
+) -> Option<&'r Symbol<'data, 'file>> {
+    let mut closest_symbol_index = match symbols.binary_search_by_key(&address, |s| s.address()) {
+        Ok(index) => Some(index),
+        Err(index) => index.checked_sub(1),
+    }?;
+    // The binary search may not find the first symbol at the address, so work backwards
+    let target_address = symbols[closest_symbol_index].address();
+    while let Some(prev_index) = closest_symbol_index.checked_sub(1) {
+        if symbols[prev_index].address() != target_address {
+            break;
+        }
+        closest_symbol_index = prev_index;
+    }
+    let mut best_symbol: Option<&'r Symbol<'data, 'file>> = None;
+    for symbol in symbols.iter().skip(closest_symbol_index) {
+        if symbol.address() > address {
+            break;
+        }
+        if symbol.kind() == SymbolKind::Section
+            || (symbol.size() > 0 && (symbol.address() + symbol.size()) <= address)
+        {
+            continue;
+        }
+        // TODO priority ranking with visibility, etc
+        if let Some(best) = best_symbol {
+            if LOW_PRIORITY_SYMBOLS.contains(&best.name().unwrap_or_default())
+                && !LOW_PRIORITY_SYMBOLS.contains(&symbol.name().unwrap_or_default())
+            {
+                best_symbol = Some(symbol);
+            }
+        } else {
+            best_symbol = Some(symbol);
+        }
+    }
+    best_symbol
+}
+
 fn find_section_symbol(
     arch: &dyn ObjArch,
     obj_file: &File<'_>,
-    target: &Symbol<'_, '_>,
+    section: &Section,
+    section_symbols: &[Symbol<'_, '_>],
     address: u64,
     split_meta: Option<&SplitMeta>,
 ) -> Result<ObjSymbol> {
-    let section_index =
+    if let Some(symbol) = best_symbol(section_symbols, address) {
-        target.section_index().ok_or_else(|| anyhow::Error::msg("Unknown section index"))?;
+        return to_obj_symbol(arch, obj_file, symbol, split_meta);
-    let section = obj_file.section_by_index(section_index)?;
-    let mut closest_symbol: Option<Symbol<'_, '_>> = None;
-    for symbol in obj_file.symbols() {
-        if !matches!(symbol.section_index(), Some(idx) if idx == section_index) {
-            continue;
     }
-        if symbol.kind() == SymbolKind::Section || symbol.address() != address {
+    // Fallback to section symbol
-            if symbol.address() < address
-                && symbol.size() != 0
-                && (closest_symbol.is_none()
-                    || matches!(&closest_symbol, Some(s) if s.address() <= symbol.address()))
-            {
-                closest_symbol = Some(symbol);
-            }
-            continue;
-        }
-        return to_obj_symbol(arch, obj_file, &symbol, 0, split_meta);
-    }
-    let (name, offset) = closest_symbol
-        .and_then(|s| s.name().map(|n| (n, s.address())).ok())
-        .or_else(|| section.name().map(|n| (n, section.address())).ok())
-        .unwrap_or(("<unknown>", 0));
-    let offset_addr = address - offset;
     Ok(ObjSymbol {
-        name: name.to_string(),
+        name: section.name()?.to_string(),
         demangled_name: None,
-        address: offset,
+        address: section.address(),
-        section_address: address - section.address(),
+        section_address: 0,
         size: 0,
         size_known: false,
+        kind: ObjSymbolKind::Section,
         flags: Default::default(),
-        addend: offset_addr as i64,
+        orig_section_index: Some(section.index().0),
         virtual_address: None,
         original_index: None,
         bytes: Vec::new(),
@@ -272,6 +313,7 @@ fn relocations_by_section(
     arch: &dyn ObjArch,
     obj_file: &File<'_>,
     section: &ObjSection,
+    section_symbols: &[Vec<Symbol<'_, '_>>],
     split_meta: Option<&SplitMeta>,
 ) -> Result<Vec<ObjReloc>> {
     let obj_section = obj_file.section_by_index(SectionIndex(section.orig_index))?;
@@ -296,30 +338,36 @@ fn relocations_by_section(
             _ => bail!("Unhandled relocation target: {:?}", reloc.target()),
         };
         let flags = reloc.flags(); // TODO validate reloc here?
-        let target_section = match symbol.section() {
+        let mut addend = if reloc.has_implicit_addend() {
-            SymbolSection::Common => Some(".comm".to_string()),
-            SymbolSection::Section(idx) => {
-                obj_file.section_by_index(idx).and_then(|s| s.name().map(|s| s.to_string())).ok()
-            }
-            _ => None,
-        };
-        let addend = if reloc.has_implicit_addend() {
             arch.implcit_addend(obj_file, section, address, &reloc)?
         } else {
             reloc.addend()
         };
-        // println!("Reloc: {reloc:?}, symbol: {symbol:?}, addend: {addend:#x}");
         let target = match symbol.kind() {
             SymbolKind::Text | SymbolKind::Data | SymbolKind::Label | SymbolKind::Unknown => {
-                to_obj_symbol(arch, obj_file, &symbol, addend, split_meta)
+                to_obj_symbol(arch, obj_file, &symbol, split_meta)?
             }
             SymbolKind::Section => {
-                ensure!(addend >= 0, "Negative addend in reloc: {addend}");
+                ensure!(addend >= 0, "Negative addend in section reloc: {addend}");
-                find_section_symbol(arch, obj_file, &symbol, addend as u64, split_meta)
+                let section_index = symbol
+                    .section_index()
+                    .ok_or_else(|| anyhow!("Section symbol {symbol:?} has no section index"))?;
+                let section = obj_file.section_by_index(section_index)?;
+                let symbol = find_section_symbol(
+                    arch,
+                    obj_file,
+                    &section,
+                    &section_symbols[section_index.0],
+                    addend as u64,
+                    split_meta,
+                )?;
+                // Adjust addend to be relative to the selected symbol
+                addend = (symbol.address - section.address()) as i64;
+                symbol
             }
-            kind => Err(anyhow!("Unhandled relocation symbol type {kind:?}")),
+            kind => bail!("Unhandled relocation symbol type {kind:?}"),
-        }?;
+        };
-        relocations.push(ObjReloc { flags, address, target, target_section });
+        relocations.push(ObjReloc { flags, address, target, addend });
     }
     Ok(relocations)
 }
@@ -384,9 +432,9 @@ fn line_info(obj_file: &File<'_>, sections: &mut [ObjSection], obj_data: &[u8])
                 let mut text_sections =
                     obj_file.sections().filter(|s| s.kind() == SectionKind::Text);
                 let section_index = text_sections.next().map(|s| s.index().0);
-                let mut lines = section_index.map(|index| {
+                let mut lines = section_index
-                    &mut sections.iter_mut().find(|s| s.orig_index == index).unwrap().line_info
+                    .and_then(|index| sections.iter_mut().find(|s| s.orig_index == index))
-                });
+                    .map(|s| &mut s.line_info);
 
                 let mut rows = program.rows();
                 while let Some((_header, row)) = rows.next_row()? {
@@ -397,13 +445,9 @@ fn line_info(obj_file: &File<'_>, sections: &mut [ObjSection], obj_data: &[u8])
                         // The next row is the start of a new sequence, which means we must
                         // advance to the next .text section.
                         let section_index = text_sections.next().map(|s| s.index().0);
-                        lines = section_index.map(|index| {
+                        lines = section_index
-                            &mut sections
+                            .and_then(|index| sections.iter_mut().find(|s| s.orig_index == index))
-                                .iter_mut()
+                            .map(|s| &mut s.line_info);
-                                .find(|s| s.orig_index == index)
-                                .unwrap()
-                                .line_info
-                        });
                     }
                 }
             }
@@ -539,8 +583,9 @@ fn update_combined_symbol(symbol: ObjSymbol, address_change: i64) -> Result<ObjS
         section_address: (symbol.section_address as i64 + address_change).try_into()?,
         size: symbol.size,
         size_known: symbol.size_known,
+        kind: symbol.kind,
         flags: symbol.flags,
-        addend: symbol.addend,
+        orig_section_index: symbol.orig_section_index,
         virtual_address: if let Some(virtual_address) = symbol.virtual_address {
             Some((virtual_address as i64 + address_change).try_into()?)
         } else {
@@ -567,7 +612,7 @@ fn combine_sections(section: ObjSection, combine: ObjSection) -> Result<ObjSecti
             flags: reloc.flags,
             address: (reloc.address as i64 + address_change).try_into()?,
             target: reloc.target, // TODO: Should be updated?
-            target_section: reloc.target_section, // TODO: Same as above
+            addend: reloc.addend,
         });
     }
 
@@ -647,18 +692,40 @@ pub fn parse(data: &[u8], config: &DiffObjConfig) -> Result<ObjInfo> {
     let obj_file = File::parse(data)?;
     let arch = new_arch(&obj_file)?;
     let split_meta = split_meta(&obj_file)?;
+
+    // Create sorted symbol list for each section
+    let mut section_symbols = Vec::with_capacity(obj_file.sections().count());
+    for section in obj_file.sections() {
+        let mut symbols = obj_file
+            .symbols()
+            .filter(|s| s.section_index() == Some(section.index()))
+            .collect::<Vec<_>>();
+        symbols.sort_by_key(|s| s.address());
+        let section_index = section.index().0;
+        if section_index >= section_symbols.len() {
+            section_symbols.resize_with(section_index + 1, Vec::new);
+        }
+        section_symbols[section_index] = symbols;
+    }
+
     let mut sections = filter_sections(&obj_file, split_meta.as_ref())?;
-    let mut name_counts: HashMap<String, u32> = HashMap::new();
+    let mut section_name_counts: HashMap<String, u32> = HashMap::new();
     for section in &mut sections {
         section.symbols = symbols_by_section(
             arch.as_ref(),
             &obj_file,
             section,
+            &section_symbols[section.orig_index],
+            split_meta.as_ref(),
+            &mut section_name_counts,
+        )?;
+        section.relocations = relocations_by_section(
+            arch.as_ref(),
+            &obj_file,
+            section,
+            &section_symbols,
             split_meta.as_ref(),
-            &mut name_counts,
         )?;
-        section.relocations =
-            relocations_by_section(arch.as_ref(), &obj_file, section, split_meta.as_ref())?;
     }
     if config.combine_data_sections {
         combine_data_sections(&mut sections)?;

objdiff-gui/src/app.rs

@@ -15,7 +15,8 @@ use globset::{Glob, GlobSet};
 use notify::{RecursiveMode, Watcher};
 use objdiff_core::{
     config::{
-        build_globset, ProjectConfigInfo, ProjectObject, ScratchConfig, DEFAULT_WATCH_PATTERNS,
+        build_globset, save_project_config, ProjectConfig, ProjectConfigInfo, ProjectObject,
+        ScratchConfig, SymbolMappings, DEFAULT_WATCH_PATTERNS,
     },
     diff::DiffObjConfig,
 };
@@ -42,11 +43,10 @@ use crate::{
         graphics::{graphics_window, GraphicsConfig, GraphicsViewState},
         jobs::{jobs_menu_ui, jobs_window},
         rlwinm::{rlwinm_decode_window, RlwinmDecodeViewState},
-        symbol_diff::{symbol_diff_ui, DiffViewState, View},
+        symbol_diff::{symbol_diff_ui, DiffViewAction, DiffViewNavigation, DiffViewState, View},
     },
 };
 
-#[derive(Default)]
 pub struct ViewState {
     pub jobs: JobQueue,
     pub config_state: ConfigViewState,
@@ -63,10 +63,34 @@ pub struct ViewState {
     pub show_debug: bool,
     pub show_graphics: bool,
     pub show_jobs: bool,
+    pub show_side_panel: bool,
+}
+
+impl Default for ViewState {
+    fn default() -> Self {
+        Self {
+            jobs: Default::default(),
+            config_state: Default::default(),
+            demangle_state: Default::default(),
+            rlwinm_decode_state: Default::default(),
+            diff_state: Default::default(),
+            graphics_state: Default::default(),
+            frame_history: Default::default(),
+            show_appearance_config: false,
+            show_demangle: false,
+            show_rlwinm_decode: false,
+            show_project_config: false,
+            show_arch_config: false,
+            show_debug: false,
+            show_graphics: false,
+            show_jobs: false,
+            show_side_panel: true,
+        }
+    }
 }
 
 /// The configuration for a single object file.
-#[derive(Clone, Eq, PartialEq, serde::Deserialize, serde::Serialize)]
+#[derive(Default, Clone, Eq, PartialEq, serde::Deserialize, serde::Serialize)]
 pub struct ObjectConfig {
     pub name: String,
     pub target_path: Option<PathBuf>,
@@ -75,6 +99,23 @@ pub struct ObjectConfig {
     pub complete: Option<bool>,
     pub scratch: Option<ScratchConfig>,
     pub source_path: Option<String>,
+    #[serde(default)]
+    pub symbol_mappings: SymbolMappings,
+}
+
+impl From<&ProjectObject> for ObjectConfig {
+    fn from(object: &ProjectObject) -> Self {
+        Self {
+            name: object.name().to_string(),
+            target_path: object.target_path.clone(),
+            base_path: object.base_path.clone(),
+            reverse_fn_order: object.reverse_fn_order(),
+            complete: object.complete(),
+            scratch: object.scratch.clone(),
+            source_path: object.source_path().cloned(),
+            symbol_mappings: object.symbol_mappings.clone().unwrap_or_default(),
+        }
+    }
 }
 
 #[inline]
@@ -94,8 +135,14 @@ pub struct AppState {
     pub obj_change: bool,
     pub queue_build: bool,
     pub queue_reload: bool,
+    pub current_project_config: Option<ProjectConfig>,
     pub project_config_info: Option<ProjectConfigInfo>,
     pub last_mod_check: Instant,
+    /// The right object symbol name that we're selecting a left symbol for
+    pub selecting_left: Option<String>,
+    /// The left object symbol name that we're selecting a right symbol for
+    pub selecting_right: Option<String>,
+    pub config_error: Option<String>,
 }
 
 impl Default for AppState {
@@ -109,8 +156,12 @@ impl Default for AppState {
             obj_change: false,
             queue_build: false,
             queue_reload: false,
+            current_project_config: None,
             project_config_info: None,
             last_mod_check: Instant::now(),
+            selecting_left: None,
+            selecting_right: None,
+            config_error: None,
         }
     }
 }
@@ -191,7 +242,10 @@ impl AppState {
         self.config_change = true;
         self.obj_change = true;
         self.queue_build = false;
+        self.current_project_config = None;
         self.project_config_info = None;
+        self.selecting_left = None;
+        self.selecting_right = None;
     }
 
     pub fn set_target_obj_dir(&mut self, path: PathBuf) {
@@ -199,6 +253,8 @@ impl AppState {
         self.config.selected_obj = None;
         self.obj_change = true;
         self.queue_build = false;
+        self.selecting_left = None;
+        self.selecting_right = None;
     }
 
     pub fn set_base_obj_dir(&mut self, path: PathBuf) {
@@ -206,12 +262,132 @@ impl AppState {
         self.config.selected_obj = None;
         self.obj_change = true;
         self.queue_build = false;
+        self.selecting_left = None;
+        self.selecting_right = None;
     }
 
-    pub fn set_selected_obj(&mut self, object: ObjectConfig) {
+    pub fn set_selected_obj(&mut self, config: ObjectConfig) {
-        self.config.selected_obj = Some(object);
+        let mut unit_changed = true;
+        if let Some(existing) = self.config.selected_obj.as_ref() {
+            if existing == &config {
+                // Don't reload the object if there were no changes
+                return;
+            }
+            if existing.name == config.name {
+                unit_changed = false;
+            }
+        }
+        self.config.selected_obj = Some(config);
+        if unit_changed {
             self.obj_change = true;
             self.queue_build = false;
+            self.selecting_left = None;
+            self.selecting_right = None;
+        } else {
+            self.queue_build = true;
+        }
+    }
+
+    pub fn clear_selected_obj(&mut self) {
+        self.config.selected_obj = None;
+        self.obj_change = true;
+        self.queue_build = false;
+        self.selecting_left = None;
+        self.selecting_right = None;
+    }
+
+    pub fn set_selecting_left(&mut self, right: &str) {
+        let Some(object) = self.config.selected_obj.as_mut() else {
+            return;
+        };
+        object.symbol_mappings.remove_by_right(right);
+        self.selecting_left = Some(right.to_string());
+        self.queue_reload = true;
+        self.save_config();
+    }
+
+    pub fn set_selecting_right(&mut self, left: &str) {
+        let Some(object) = self.config.selected_obj.as_mut() else {
+            return;
+        };
+        object.symbol_mappings.remove_by_left(left);
+        self.selecting_right = Some(left.to_string());
+        self.queue_reload = true;
+        self.save_config();
+    }
+
+    pub fn set_symbol_mapping(&mut self, left: String, right: String) {
+        let Some(object) = self.config.selected_obj.as_mut() else {
+            log::warn!("No selected object");
+            return;
+        };
+        self.selecting_left = None;
+        self.selecting_right = None;
+        if left == right {
+            object.symbol_mappings.remove_by_left(&left);
+            object.symbol_mappings.remove_by_right(&right);
+        } else {
+            object.symbol_mappings.insert(left.clone(), right.clone());
+        }
+        self.queue_reload = true;
+        self.save_config();
+    }
+
+    pub fn clear_selection(&mut self) {
+        self.selecting_left = None;
+        self.selecting_right = None;
+        self.queue_reload = true;
+    }
+
+    pub fn clear_mappings(&mut self) {
+        self.selecting_left = None;
+        self.selecting_right = None;
+        if let Some(object) = self.config.selected_obj.as_mut() {
+            object.symbol_mappings.clear();
+        }
+        self.queue_reload = true;
+        self.save_config();
+    }
+
+    pub fn is_selecting_symbol(&self) -> bool {
+        self.selecting_left.is_some() || self.selecting_right.is_some()
+    }
+
+    pub fn save_config(&mut self) {
+        let (Some(config), Some(info)) =
+            (self.current_project_config.as_mut(), self.project_config_info.as_mut())
+        else {
+            return;
+        };
+        // Update the project config with the current state
+        if let Some(object) = self.config.selected_obj.as_ref() {
+            if let Some(existing) = config.units.as_mut().and_then(|v| {
+                v.iter_mut().find(|u| u.name.as_ref().is_some_and(|n| n == &object.name))
+            }) {
+                existing.symbol_mappings = if object.symbol_mappings.is_empty() {
+                    None
+                } else {
+                    Some(object.symbol_mappings.clone())
+                };
+            }
+            if let Some(existing) =
+                self.objects.iter_mut().find(|u| u.name.as_ref().is_some_and(|n| n == &object.name))
+            {
+                existing.symbol_mappings = if object.symbol_mappings.is_empty() {
+                    None
+                } else {
+                    Some(object.symbol_mappings.clone())
+                };
+            }
+        }
+        // Save the updated project config
+        match save_project_config(config, info) {
+            Ok(new_info) => *info = new_info,
+            Err(e) => {
+                log::error!("Failed to save project config: {e}");
+                self.config_error = Some(format!("Failed to save project config: {e}"));
+            }
+        }
     }
 }
 
@@ -350,31 +526,41 @@ impl App {
         debug_assert!(jobs.results.is_empty());
     }
 
-    fn post_update(&mut self, ctx: &egui::Context) {
+    fn post_update(&mut self, ctx: &egui::Context, action: Option<DiffViewAction>) {
         self.appearance.post_update(ctx);
 
         let ViewState { jobs, diff_state, config_state, graphics_state, .. } = &mut self.view_state;
         config_state.post_update(ctx, jobs, &self.state);
-        diff_state.post_update(ctx, jobs, &self.state);
+        diff_state.post_update(action, ctx, jobs, &self.state);
 
         let Ok(mut state) = self.state.write() else {
             return;
         };
         let state = &mut *state;
 
+        let mut mod_check = false;
+        if state.last_mod_check.elapsed().as_millis() >= 500 {
+            state.last_mod_check = Instant::now();
+            mod_check = true;
+        }
+
+        if mod_check {
             if let Some(info) = &state.project_config_info {
-            if file_modified(&info.path, info.timestamp) {
+                if let Some(last_ts) = info.timestamp {
+                    if file_modified(&info.path, last_ts) {
                         state.config_change = true;
                     }
                 }
+            }
+        }
 
         if state.config_change {
             state.config_change = false;
             match load_project_config(state) {
-                Ok(()) => config_state.load_error = None,
+                Ok(()) => state.config_error = None,
                 Err(e) => {
                     log::error!("Failed to load project config: {e}");
-                    config_state.load_error = Some(format!("{e}"));
+                    state.config_error = Some(format!("{e}"));
                 }
             }
         }
@@ -409,8 +595,7 @@ impl App {
         }
 
         if let Some(result) = &diff_state.build {
-            if state.last_mod_check.elapsed().as_millis() >= 500 {
+            if mod_check {
-                state.last_mod_check = Instant::now();
                 if let Some((obj, _)) = &result.first_obj {
                     if let (Some(path), Some(timestamp)) = (&obj.path, obj.timestamp) {
                         if file_modified(path, timestamp) {
@@ -434,11 +619,11 @@ impl App {
             && state.config.selected_obj.is_some()
             && !jobs.is_running(Job::ObjDiff)
         {
-            jobs.push(start_build(ctx, ObjDiffConfig::from_config(&state.config)));
+            jobs.push(start_build(ctx, ObjDiffConfig::from_state(state)));
             state.queue_build = false;
             state.queue_reload = false;
         } else if state.queue_reload && !jobs.is_running(Job::ObjDiff) {
-            let mut diff_config = ObjDiffConfig::from_config(&state.config);
+            let mut diff_config = ObjDiffConfig::from_state(state);
             // Don't build, just reload the current files
             diff_config.build_base = false;
             diff_config.build_target = false;
@@ -485,12 +670,26 @@ impl eframe::App for App {
             show_debug,
             show_graphics,
             show_jobs,
+            show_side_panel,
         } = view_state;
 
         frame_history.on_new_frame(ctx.input(|i| i.time), frame.info().cpu_usage);
 
+        let side_panel_available = diff_state.current_view == View::SymbolDiff;
+
         egui::TopBottomPanel::top("top_panel").show(ctx, |ui| {
             egui::menu::bar(ui, |ui| {
+                if ui
+                    .add_enabled(
+                        side_panel_available,
+                        egui::Button::new(if *show_side_panel { "⏴" } else { "⏵" }),
+                    )
+                    .on_hover_text("Toggle side panel")
+                    .clicked()
+                {
+                    *show_side_panel = !*show_side_panel;
+                }
+                ui.separator();
                 ui.menu_button("File", |ui| {
                     #[cfg(debug_assertions)]
                     if ui.button("Debug…").clicked() {
@@ -599,6 +798,11 @@ impl eframe::App for App {
                     {
                         state.queue_reload = true;
                     }
+                    if ui.button("Clear custom symbol mappings").clicked() {
+                        state.clear_mappings();
+                        diff_state.post_build_nav = Some(DiffViewNavigation::symbol_diff());
+                        state.queue_reload = true;
+                    }
                 });
                 ui.separator();
                 if jobs_menu_ui(ui, jobs, appearance) {
@@ -607,31 +811,28 @@ impl eframe::App for App {
             });
         });
 
-        let build_success = matches!(&diff_state.build, Some(b) if b.first_status.success && b.second_status.success);
+        if side_panel_available {
-        if diff_state.current_view == View::FunctionDiff && build_success {
+            egui::SidePanel::left("side_panel").show_animated(ctx, *show_side_panel, |ui| {
-            egui::CentralPanel::default().show(ctx, |ui| {
-                function_diff_ui(ui, diff_state, appearance);
-            });
-        } else if diff_state.current_view == View::DataDiff && build_success {
-            egui::CentralPanel::default().show(ctx, |ui| {
-                data_diff_ui(ui, diff_state, appearance);
-            });
-        } else if diff_state.current_view == View::ExtabDiff && build_success {
-            egui::CentralPanel::default().show(ctx, |ui| {
-                extab_diff_ui(ui, diff_state, appearance);
-            });
-        } else {
-            egui::SidePanel::left("side_panel").show(ctx, |ui| {
                 egui::ScrollArea::both().show(ui, |ui| {
                     config_ui(ui, state, show_project_config, config_state, appearance);
                 });
             });
-
-            egui::CentralPanel::default().show(ctx, |ui| {
-                symbol_diff_ui(ui, diff_state, appearance);
-            });
         }
 
+        let mut action = None;
+        egui::CentralPanel::default().show(ctx, |ui| {
+            let build_success = matches!(&diff_state.build, Some(b) if b.first_status.success && b.second_status.success);
+            action = if diff_state.current_view == View::FunctionDiff && build_success {
+                function_diff_ui(ui, diff_state, appearance)
+            } else if diff_state.current_view == View::DataDiff && build_success {
+                data_diff_ui(ui, diff_state, appearance)
+            } else if diff_state.current_view == View::ExtabDiff && build_success {
+                extab_diff_ui(ui, diff_state, appearance)
+            } else {
+                symbol_diff_ui(ui, diff_state, appearance)
+            };
+        });
+
         project_window(ctx, state, show_project_config, config_state, appearance);
         appearance_window(ctx, show_appearance_config, appearance);
         demangle_window(ctx, show_demangle, demangle_state, appearance);
@@ -641,10 +842,10 @@ impl eframe::App for App {
         graphics_window(ctx, show_graphics, frame_history, graphics_state, appearance);
         jobs_window(ctx, show_jobs, jobs, appearance);
 
-        self.post_update(ctx);
+        self.post_update(ctx, action);
     }
 
-    /// Called by the frame work to save state before shutdown.
+    /// Called by the framework to save state before shutdown.
     fn save(&mut self, storage: &mut dyn eframe::Storage) {
         if let Ok(state) = self.state.read() {
             eframe::set_value(storage, CONFIG_KEY, &state.config);

objdiff-gui/src/app_config.rs

@@ -2,6 +2,10 @@ use std::path::PathBuf;
 
 use eframe::Storage;
 use globset::Glob;
+use objdiff_core::{
+    config::ScratchConfig,
+    diff::{ArmArchVersion, ArmR9Usage, DiffObjConfig, MipsAbi, MipsInstrCategory, X86Formatter},
+};
 
 use crate::app::{AppConfig, ObjectConfig, CONFIG_KEY};
 
@@ -11,7 +15,7 @@ pub struct AppConfigVersion {
 }
 
 impl Default for AppConfigVersion {
-    fn default() -> Self { Self { version: 1 } }
+    fn default() -> Self { Self { version: 2 } }
 }
 
 /// Deserialize the AppConfig from storage, handling upgrades from older versions.
@@ -19,7 +23,8 @@ pub fn deserialize_config(storage: &dyn Storage) -> Option<AppConfig> {
     let str = storage.get_string(CONFIG_KEY)?;
     match ron::from_str::<AppConfigVersion>(&str) {
         Ok(version) => match version.version {
-            1 => from_str::<AppConfig>(&str),
+            2 => from_str::<AppConfig>(&str),
+            1 => from_str::<AppConfigV1>(&str).map(|c| c.into_config()),
             _ => {
                 log::warn!("Unknown config version: {}", version.version);
                 None
@@ -44,6 +49,180 @@ where T: serde::de::DeserializeOwned {
     }
 }
 
+#[derive(serde::Deserialize, serde::Serialize)]
+pub struct ScratchConfigV1 {
+    #[serde(default)]
+    pub platform: Option<String>,
+    #[serde(default)]
+    pub compiler: Option<String>,
+    #[serde(default)]
+    pub c_flags: Option<String>,
+    #[serde(default)]
+    pub ctx_path: Option<PathBuf>,
+    #[serde(default)]
+    pub build_ctx: bool,
+}
+
+impl ScratchConfigV1 {
+    fn into_config(self) -> ScratchConfig {
+        ScratchConfig {
+            platform: self.platform,
+            compiler: self.compiler,
+            c_flags: self.c_flags,
+            ctx_path: self.ctx_path,
+            build_ctx: self.build_ctx.then_some(true),
+        }
+    }
+}
+
+#[derive(serde::Deserialize, serde::Serialize)]
+pub struct ObjectConfigV1 {
+    pub name: String,
+    pub target_path: Option<PathBuf>,
+    pub base_path: Option<PathBuf>,
+    pub reverse_fn_order: Option<bool>,
+    pub complete: Option<bool>,
+    pub scratch: Option<ScratchConfigV1>,
+    pub source_path: Option<String>,
+}
+
+impl ObjectConfigV1 {
+    fn into_config(self) -> ObjectConfig {
+        ObjectConfig {
+            name: self.name,
+            target_path: self.target_path,
+            base_path: self.base_path,
+            reverse_fn_order: self.reverse_fn_order,
+            complete: self.complete,
+            scratch: self.scratch.map(|scratch| scratch.into_config()),
+            source_path: self.source_path,
+            ..Default::default()
+        }
+    }
+}
+
+#[derive(serde::Deserialize, serde::Serialize)]
+#[serde(default)]
+pub struct DiffObjConfigV1 {
+    pub relax_reloc_diffs: bool,
+    #[serde(default = "bool_true")]
+    pub space_between_args: bool,
+    pub combine_data_sections: bool,
+    // x86
+    pub x86_formatter: X86Formatter,
+    // MIPS
+    pub mips_abi: MipsAbi,
+    pub mips_instr_category: MipsInstrCategory,
+    // ARM
+    pub arm_arch_version: ArmArchVersion,
+    pub arm_unified_syntax: bool,
+    pub arm_av_registers: bool,
+    pub arm_r9_usage: ArmR9Usage,
+    pub arm_sl_usage: bool,
+    pub arm_fp_usage: bool,
+    pub arm_ip_usage: bool,
+}
+
+impl Default for DiffObjConfigV1 {
+    fn default() -> Self {
+        Self {
+            relax_reloc_diffs: false,
+            space_between_args: true,
+            combine_data_sections: false,
+            x86_formatter: Default::default(),
+            mips_abi: Default::default(),
+            mips_instr_category: Default::default(),
+            arm_arch_version: Default::default(),
+            arm_unified_syntax: true,
+            arm_av_registers: false,
+            arm_r9_usage: Default::default(),
+            arm_sl_usage: false,
+            arm_fp_usage: false,
+            arm_ip_usage: false,
+        }
+    }
+}
+
+impl DiffObjConfigV1 {
+    fn into_config(self) -> DiffObjConfig {
+        DiffObjConfig {
+            relax_reloc_diffs: self.relax_reloc_diffs,
+            space_between_args: self.space_between_args,
+            combine_data_sections: self.combine_data_sections,
+            x86_formatter: self.x86_formatter,
+            mips_abi: self.mips_abi,
+            mips_instr_category: self.mips_instr_category,
+            arm_arch_version: self.arm_arch_version,
+            arm_unified_syntax: self.arm_unified_syntax,
+            arm_av_registers: self.arm_av_registers,
+            arm_r9_usage: self.arm_r9_usage,
+            arm_sl_usage: self.arm_sl_usage,
+            arm_fp_usage: self.arm_fp_usage,
+            arm_ip_usage: self.arm_ip_usage,
+            ..Default::default()
+        }
+    }
+}
+
+#[inline]
+fn bool_true() -> bool { true }
+
+#[derive(serde::Deserialize, serde::Serialize)]
+pub struct AppConfigV1 {
+    pub version: u32,
+    #[serde(default)]
+    pub custom_make: Option<String>,
+    #[serde(default)]
+    pub custom_args: Option<Vec<String>>,
+    #[serde(default)]
+    pub selected_wsl_distro: Option<String>,
+    #[serde(default)]
+    pub project_dir: Option<PathBuf>,
+    #[serde(default)]
+    pub target_obj_dir: Option<PathBuf>,
+    #[serde(default)]
+    pub base_obj_dir: Option<PathBuf>,
+    #[serde(default)]
+    pub selected_obj: Option<ObjectConfigV1>,
+    #[serde(default = "bool_true")]
+    pub build_base: bool,
+    #[serde(default)]
+    pub build_target: bool,
+    #[serde(default = "bool_true")]
+    pub rebuild_on_changes: bool,
+    #[serde(default)]
+    pub auto_update_check: bool,
+    #[serde(default)]
+    pub watch_patterns: Vec<Glob>,
+    #[serde(default)]
+    pub recent_projects: Vec<PathBuf>,
+    #[serde(default)]
+    pub diff_obj_config: DiffObjConfigV1,
+}
+
+impl AppConfigV1 {
+    fn into_config(self) -> AppConfig {
+        log::info!("Upgrading configuration from v1");
+        AppConfig {
+            custom_make: self.custom_make,
+            custom_args: self.custom_args,
+            selected_wsl_distro: self.selected_wsl_distro,
+            project_dir: self.project_dir,
+            target_obj_dir: self.target_obj_dir,
+            base_obj_dir: self.base_obj_dir,
+            selected_obj: self.selected_obj.map(|obj| obj.into_config()),
+            build_base: self.build_base,
+            build_target: self.build_target,
+            rebuild_on_changes: self.rebuild_on_changes,
+            auto_update_check: self.auto_update_check,
+            watch_patterns: self.watch_patterns,
+            recent_projects: self.recent_projects,
+            diff_obj_config: self.diff_obj_config.into_config(),
+            ..Default::default()
+        }
+    }
+}
+
 #[derive(serde::Deserialize, serde::Serialize)]
 pub struct ObjectConfigV0 {
     pub name: String,
@@ -59,9 +238,7 @@ impl ObjectConfigV0 {
             target_path: Some(self.target_path),
             base_path: Some(self.base_path),
             reverse_fn_order: self.reverse_fn_order,
-            complete: None,
+            ..Default::default()
-            scratch: None,
-            source_path: None,
         }
     }
 }

objdiff-gui/src/config.rs

@@ -4,11 +4,11 @@ use anyhow::Result;
 use globset::Glob;
 use objdiff_core::config::{try_project_config, ProjectObject, DEFAULT_WATCH_PATTERNS};
 
-use crate::app::AppState;
+use crate::app::{AppState, ObjectConfig};
 
 #[derive(Clone)]
 pub enum ProjectObjectNode {
-    File(String, Box<ProjectObject>),
+    Unit(String, usize),
     Dir(String, Vec<ProjectObjectNode>),
 }
 
@@ -33,17 +33,18 @@ fn find_dir<'a>(
 }
 
 fn build_nodes(
-    objects: &[ProjectObject],
+    units: &mut [ProjectObject],
     project_dir: &Path,
     target_obj_dir: Option<&Path>,
     base_obj_dir: Option<&Path>,
 ) -> Vec<ProjectObjectNode> {
     let mut nodes = vec![];
-    for object in objects {
+    for (idx, unit) in units.iter_mut().enumerate() {
+        unit.resolve_paths(project_dir, target_obj_dir, base_obj_dir);
         let mut out_nodes = &mut nodes;
-        let path = if let Some(name) = &object.name {
+        let path = if let Some(name) = &unit.name {
             Path::new(name)
-        } else if let Some(path) = &object.path {
+        } else if let Some(path) = &unit.path {
             path
         } else {
             continue;
@@ -56,10 +57,8 @@ fn build_nodes(
                 }
             }
         }
-        let mut object = Box::new(object.clone());
-        object.resolve_paths(project_dir, target_obj_dir, base_obj_dir);
         let filename = path.file_name().unwrap().to_str().unwrap().to_string();
-        out_nodes.push(ProjectObjectNode::File(filename, object));
+        out_nodes.push(ProjectObjectNode::Unit(filename, idx));
     }
     nodes
 }
@@ -70,24 +69,36 @@ pub fn load_project_config(state: &mut AppState) -> Result<()> {
     };
     if let Some((result, info)) = try_project_config(project_dir) {
         let project_config = result?;
-        state.config.custom_make = project_config.custom_make;
+        state.config.custom_make = project_config.custom_make.clone();
-        state.config.custom_args = project_config.custom_args;
+        state.config.custom_args = project_config.custom_args.clone();
-        state.config.target_obj_dir = project_config.target_dir.map(|p| project_dir.join(p));
+        state.config.target_obj_dir =
-        state.config.base_obj_dir = project_config.base_dir.map(|p| project_dir.join(p));
+            project_config.target_dir.as_deref().map(|p| project_dir.join(p));
-        state.config.build_base = project_config.build_base;
+        state.config.base_obj_dir = project_config.base_dir.as_deref().map(|p| project_dir.join(p));
-        state.config.build_target = project_config.build_target;
+        state.config.build_base = project_config.build_base.unwrap_or(true);
-        state.config.watch_patterns = project_config.watch_patterns.unwrap_or_else(|| {
+        state.config.build_target = project_config.build_target.unwrap_or(false);
+        state.config.watch_patterns = project_config.watch_patterns.clone().unwrap_or_else(|| {
             DEFAULT_WATCH_PATTERNS.iter().map(|s| Glob::new(s).unwrap()).collect()
         });
         state.watcher_change = true;
-        state.objects = project_config.objects;
+        state.objects = project_config.units.clone().unwrap_or_default();
         state.object_nodes = build_nodes(
-            &state.objects,
+            &mut state.objects,
             project_dir,
             state.config.target_obj_dir.as_deref(),
             state.config.base_obj_dir.as_deref(),
         );
+        state.current_project_config = Some(project_config);
         state.project_config_info = Some(info);
+
+        // Reload selected object
+        if let Some(selected_obj) = &state.config.selected_obj {
+            if let Some(obj) = state.objects.iter().find(|o| o.name() == selected_obj.name) {
+                let config = ObjectConfig::from(obj);
+                state.set_selected_obj(config);
+            } else {
+                state.clear_selected_obj();
+            }
+        }
     }
     Ok(())
 }

objdiff-gui/src/jobs/create_scratch.rs

@@ -39,7 +39,7 @@ impl CreateScratchConfig {
         Ok(Self {
             build_config: BuildConfig::from_config(config),
             context_path: scratch_config.ctx_path.clone(),
-            build_context: scratch_config.build_ctx,
+            build_context: scratch_config.build_ctx.unwrap_or(false),
             compiler: scratch_config.compiler.clone().unwrap_or_default(),
             platform: scratch_config.platform.clone().unwrap_or_default(),
             compiler_flags: scratch_config.c_flags.clone().unwrap_or_default(),

objdiff-gui/src/jobs/mod.rs

@@ -53,7 +53,7 @@ impl JobQueue {
     }
 
     /// Returns whether any job is running.
-    #[allow(dead_code)]
+    #[expect(dead_code)]
     pub fn any_running(&self) -> bool {
         self.jobs.iter().any(|job| {
             if let Some(handle) = &job.handle {

objdiff-gui/src/jobs/objdiff.rs

@@ -6,13 +6,13 @@ use std::{
 
 use anyhow::{anyhow, Error, Result};
 use objdiff_core::{
-    diff::{diff_objs, DiffObjConfig, ObjDiff},
+    diff::{diff_objs, DiffObjConfig, MappingConfig, ObjDiff},
     obj::{read, ObjInfo},
 };
 use time::OffsetDateTime;
 
 use crate::{
-    app::{AppConfig, ObjectConfig},
+    app::{AppConfig, AppState, ObjectConfig},
     jobs::{start_job, update_status, Job, JobContext, JobResult, JobState},
 };
 
@@ -60,16 +60,20 @@ pub struct ObjDiffConfig {
     pub build_target: bool,
     pub selected_obj: Option<ObjectConfig>,
     pub diff_obj_config: DiffObjConfig,
+    pub selecting_left: Option<String>,
+    pub selecting_right: Option<String>,
 }
 
 impl ObjDiffConfig {
-    pub(crate) fn from_config(config: &AppConfig) -> Self {
+    pub(crate) fn from_state(state: &AppState) -> Self {
         Self {
-            build_config: BuildConfig::from_config(config),
+            build_config: BuildConfig::from_config(&state.config),
-            build_base: config.build_base,
+            build_base: state.config.build_base,
-            build_target: config.build_target,
+            build_target: state.config.build_target,
-            selected_obj: config.selected_obj.clone(),
+            selected_obj: state.config.selected_obj.clone(),
-            diff_obj_config: config.diff_obj_config.clone(),
+            diff_obj_config: state.config.diff_obj_config.clone(),
+            selecting_left: state.selecting_left.clone(),
+            selecting_right: state.selecting_right.clone(),
         }
     }
 }
@@ -158,9 +162,16 @@ pub(crate) fn run_make(config: &BuildConfig, arg: &Path) -> BuildStatus {
 fn run_build(
     context: &JobContext,
     cancel: Receiver<()>,
-    config: ObjDiffConfig,
+    mut config: ObjDiffConfig,
 ) -> Result<Box<ObjDiffResult>> {
-    let obj_config = config.selected_obj.as_ref().ok_or_else(|| Error::msg("Missing obj path"))?;
+    let obj_config = config.selected_obj.ok_or_else(|| Error::msg("Missing obj path"))?;
+    // Use the per-object symbol mappings, we don't set mappings globally
+    config.diff_obj_config.symbol_mappings = MappingConfig {
+        mappings: obj_config.symbol_mappings,
+        selecting_left: config.selecting_left,
+        selecting_right: config.selecting_right,
+    };
+
     let project_dir = config
         .build_config
         .project_dir

objdiff-gui/src/views/appearance.rs

@@ -205,7 +205,7 @@ pub const DEFAULT_COLOR_ROTATION: [Color32; 9] = [
     Color32::from_rgb(255, 0, 0),
     Color32::from_rgb(255, 255, 0),
     Color32::from_rgb(255, 192, 203),
-    Color32::from_rgb(0, 0, 255),
+    Color32::from_rgb(128, 128, 255),
     Color32::from_rgb(0, 255, 0),
     Color32::from_rgb(213, 138, 138),
 ];

objdiff-gui/src/views/column_layout.rs

@@ -0,0 +1,82 @@
+use egui::{Align, Layout, Sense, Vec2};
+use egui_extras::{Column, Size, StripBuilder, TableBuilder, TableRow};
+
+pub fn render_header(
+    ui: &mut egui::Ui,
+    available_width: f32,
+    num_columns: usize,
+    mut add_contents: impl FnMut(&mut egui::Ui, usize),
+) {
+    let column_width = available_width / num_columns as f32;
+    ui.allocate_ui_with_layout(
+        Vec2 { x: available_width, y: 100.0 },
+        Layout::left_to_right(Align::Min),
+        |ui| {
+            ui.style_mut().wrap_mode = Some(egui::TextWrapMode::Truncate);
+            for i in 0..num_columns {
+                ui.allocate_ui_with_layout(
+                    Vec2 { x: column_width, y: 100.0 },
+                    Layout::top_down(Align::Min),
+                    |ui| {
+                        ui.set_width(column_width);
+                        add_contents(ui, i);
+                    },
+                );
+            }
+        },
+    );
+    ui.separator();
+}
+
+pub fn render_table(
+    ui: &mut egui::Ui,
+    available_width: f32,
+    num_columns: usize,
+    row_height: f32,
+    total_rows: usize,
+    mut add_contents: impl FnMut(&mut TableRow, usize),
+) {
+    ui.style_mut().interaction.selectable_labels = false;
+    let column_width = available_width / num_columns as f32;
+    let available_height = ui.available_height();
+    let table = TableBuilder::new(ui)
+        .striped(false)
+        .cell_layout(Layout::left_to_right(Align::Min))
+        .columns(Column::exact(column_width).clip(true), num_columns)
+        .resizable(false)
+        .auto_shrink([false, false])
+        .min_scrolled_height(available_height)
+        .sense(Sense::click());
+    table.body(|body| {
+        body.rows(row_height, total_rows, |mut row| {
+            row.set_hovered(false); // Disable hover effect
+            for i in 0..num_columns {
+                add_contents(&mut row, i);
+            }
+        });
+    });
+}
+
+pub fn render_strips(
+    ui: &mut egui::Ui,
+    available_width: f32,
+    num_columns: usize,
+    mut add_contents: impl FnMut(&mut egui::Ui, usize),
+) {
+    let column_width = available_width / num_columns as f32;
+    StripBuilder::new(ui).size(Size::remainder()).clip(true).vertical(|mut strip| {
+        strip.strip(|builder| {
+            builder.sizes(Size::exact(column_width), num_columns).clip(true).horizontal(
+                |mut strip| {
+                    for i in 0..num_columns {
+                        strip.cell(|ui| {
+                            ui.push_id(i, |ui| {
+                                add_contents(ui, i);
+                            });
+                        });
+                    }
+                },
+            );
+        });
+    });
+}

objdiff-gui/src/views/config.rs

@@ -43,7 +43,6 @@ pub struct ConfigViewState {
     pub build_running: bool,
     pub queue_build: bool,
     pub watch_pattern_text: String,
-    pub load_error: Option<String>,
     pub object_search: String,
     pub filter_diffable: bool,
     pub filter_incomplete: bool,
@@ -93,10 +92,7 @@ impl ConfigViewState {
                             name: obj_path.display().to_string(),
                             target_path: Some(target_path),
                             base_path: Some(path),
-                            reverse_fn_order: None,
+                            ..Default::default()
-                            complete: None,
-                            scratch: None,
-                            source_path: None,
                         });
                     } else if let Ok(obj_path) = path.strip_prefix(target_dir) {
                         let base_path = base_dir.join(obj_path);
@@ -104,10 +100,7 @@ impl ConfigViewState {
                             name: obj_path.display().to_string(),
                             target_path: Some(path),
                             base_path: Some(base_path),
-                            reverse_fn_order: None,
+                            ..Default::default()
-                            complete: None,
-                            scratch: None,
-                            source_path: None,
                         });
                     }
                 }
@@ -230,7 +223,10 @@ pub fn config_ui(
         }
     });
 
-    let mut new_selected_obj = selected_obj.clone();
+    let selected_index = selected_obj.as_ref().and_then(|selected_obj| {
+        objects.iter().position(|obj| obj.name.as_ref() == Some(&selected_obj.name))
+    });
+    let mut new_selected_index = selected_index;
     if objects.is_empty() {
         if let (Some(_base_dir), Some(target_dir)) = (base_obj_dir, target_obj_dir) {
             if ui.button("Select object").clicked() {
@@ -316,6 +312,7 @@ pub fn config_ui(
             ui.style_mut().wrap_mode = Some(egui::TextWrapMode::Extend);
             for node in object_nodes.iter().filter_map(|node| {
                 filter_node(
+                    objects,
                     node,
                     &search,
                     config_state.filter_diffable,
@@ -325,8 +322,9 @@ pub fn config_ui(
             }) {
                 display_node(
                     ui,
-                    &mut new_selected_obj,
+                    &mut new_selected_index,
                     project_dir.as_deref(),
+                    objects,
                     &node,
                     appearance,
                     node_open,
@@ -334,10 +332,11 @@ pub fn config_ui(
             }
         });
     }
-    if new_selected_obj != *selected_obj {
+    if new_selected_index != selected_index {
-        if let Some(obj) = new_selected_obj {
+        if let Some(idx) = new_selected_index {
             // Will set obj_changed, which will trigger a rebuild
-            state_guard.set_selected_obj(obj);
+            let config = ObjectConfig::from(&objects[idx]);
+            state_guard.set_selected_obj(config);
         }
     }
     if state_guard.config.selected_obj.is_some()
@@ -347,16 +346,17 @@ pub fn config_ui(
     }
 }
 
-fn display_object(
+fn display_unit(
     ui: &mut egui::Ui,
-    selected_obj: &mut Option<ObjectConfig>,
+    selected_obj: &mut Option<usize>,
     project_dir: Option<&Path>,
     name: &str,
-    object: &ProjectObject,
+    units: &[ProjectObject],
+    index: usize,
     appearance: &Appearance,
 ) {
-    let object_name = object.name();
+    let object = &units[index];
-    let selected = matches!(selected_obj, Some(obj) if obj.name == object_name);
+    let selected = *selected_obj == Some(index);
     let color = if selected {
         appearance.emphasized_text_color
     } else if let Some(complete) = object.complete() {
@@ -381,18 +381,8 @@ fn display_object(
     if get_source_path(project_dir, object).is_some() {
         response.context_menu(|ui| object_context_ui(ui, object, project_dir));
     }
-    // Always recreate ObjectConfig if selected, in case the project config changed.
+    if response.clicked() {
-    // ObjectConfig is compared using equality, so this won't unnecessarily trigger a rebuild.
+        *selected_obj = Some(index);
-    if selected || response.clicked() {
-        *selected_obj = Some(ObjectConfig {
-            name: object_name.to_string(),
-            target_path: object.target_path.clone(),
-            base_path: object.base_path.clone(),
-            reverse_fn_order: object.reverse_fn_order(),
-            complete: object.complete(),
-            scratch: object.scratch.clone(),
-            source_path: object.source_path().cloned(),
-        });
     }
 }
 
@@ -427,18 +417,19 @@ enum NodeOpen {
 
 fn display_node(
     ui: &mut egui::Ui,
-    selected_obj: &mut Option<ObjectConfig>,
+    selected_obj: &mut Option<usize>,
     project_dir: Option<&Path>,
+    units: &[ProjectObject],
     node: &ProjectObjectNode,
     appearance: &Appearance,
     node_open: NodeOpen,
 ) {
     match node {
-        ProjectObjectNode::File(name, object) => {
+        ProjectObjectNode::Unit(name, idx) => {
-            display_object(ui, selected_obj, project_dir, name, object, appearance);
+            display_unit(ui, selected_obj, project_dir, name, units, *idx, appearance);
         }
         ProjectObjectNode::Dir(name, children) => {
-            let contains_obj = selected_obj.as_ref().map(|path| contains_node(node, path));
+            let contains_obj = selected_obj.map(|idx| contains_node(node, idx));
             let open = match node_open {
                 NodeOpen::Default => None,
                 NodeOpen::Open => Some(true),
@@ -461,16 +452,16 @@ fn display_node(
             .open(open)
             .show(ui, |ui| {
                 for node in children {
-                    display_node(ui, selected_obj, project_dir, node, appearance, node_open);
+                    display_node(ui, selected_obj, project_dir, units, node, appearance, node_open);
                 }
             });
         }
     }
 }
 
-fn contains_node(node: &ProjectObjectNode, selected_obj: &ObjectConfig) -> bool {
+fn contains_node(node: &ProjectObjectNode, selected_obj: usize) -> bool {
     match node {
-        ProjectObjectNode::File(_, object) => object.name() == selected_obj.name,
+        ProjectObjectNode::Unit(_, idx) => *idx == selected_obj,
         ProjectObjectNode::Dir(_, children) => {
             children.iter().any(|node| contains_node(node, selected_obj))
         }
@@ -478,6 +469,7 @@ fn contains_node(node: &ProjectObjectNode, selected_obj: &ObjectConfig) -> bool
 }
 
 fn filter_node(
+    units: &[ProjectObject],
     node: &ProjectObjectNode,
     search: &str,
     filter_diffable: bool,
@@ -485,12 +477,12 @@ fn filter_node(
     show_hidden: bool,
 ) -> Option<ProjectObjectNode> {
     match node {
-        ProjectObjectNode::File(name, object) => {
+        ProjectObjectNode::Unit(name, idx) => {
+            let unit = &units[*idx];
             if (search.is_empty() || name.to_ascii_lowercase().contains(search))
-                && (!filter_diffable
+                && (!filter_diffable || (unit.base_path.is_some() && unit.target_path.is_some()))
-                    || (object.base_path.is_some() && object.target_path.is_some()))
+                && (!filter_incomplete || matches!(unit.complete(), None | Some(false)))
-                && (!filter_incomplete || matches!(object.complete(), None | Some(false)))
+                && (show_hidden || !unit.hidden())
-                && (show_hidden || !object.hidden())
             {
                 Some(node.clone())
             } else {
@@ -501,7 +493,14 @@ fn filter_node(
             let new_children = children
                 .iter()
                 .filter_map(|child| {
-                    filter_node(child, search, filter_diffable, filter_incomplete, show_hidden)
+                    filter_node(
+                        units,
+                        child,
+                        search,
+                        filter_diffable,
+                        filter_incomplete,
+                        show_hidden,
+                    )
                 })
                 .collect::<Vec<_>>();
             if !new_children.is_empty() {
@@ -570,14 +569,14 @@ pub fn project_window(
         split_obj_config_ui(ui, &mut state_guard, config_state, appearance);
     });
 
-    if let Some(error) = &config_state.load_error {
+    if let Some(error) = &state_guard.config_error {
         let mut open = true;
         egui::Window::new("Error").open(&mut open).show(ctx, |ui| {
             ui.label("Failed to load project config:");
             ui.colored_label(appearance.delete_color, error);
         });
         if !open {
-            config_state.load_error = None;
+            state_guard.config_error = None;
         }
     }
 }

objdiff-gui/src/views/data_diff.rs

@@ -1,7 +1,6 @@
 use std::{cmp::min, default::Default, mem::take};
 
-use egui::{text::LayoutJob, Align, Label, Layout, Sense, Vec2, Widget};
+use egui::{text::LayoutJob, Id, Label, RichText, Sense, Widget};
-use egui_extras::{Column, TableBuilder};
 use objdiff_core::{
     diff::{ObjDataDiff, ObjDataDiffKind, ObjDiff},
     obj::ObjInfo,
@@ -10,14 +9,15 @@ use time::format_description;
 
 use crate::views::{
     appearance::Appearance,
-    symbol_diff::{DiffViewState, SymbolRefByName, View},
+    column_layout::{render_header, render_table},
+    symbol_diff::{DiffViewAction, DiffViewNavigation, DiffViewState},
     write_text,
 };
 
 const BYTES_PER_ROW: usize = 16;
 
-fn find_section(obj: &ObjInfo, selected_symbol: &SymbolRefByName) -> Option<usize> {
+fn find_section(obj: &ObjInfo, section_name: &str) -> Option<usize> {
-    obj.sections.iter().position(|section| section.name == selected_symbol.section_name)
+    obj.sections.iter().position(|section| section.name == section_name)
 }
 
 fn data_row_ui(ui: &mut egui::Ui, address: usize, diffs: &[ObjDataDiff], appearance: &Appearance) {
@@ -131,20 +131,37 @@ fn split_diffs(diffs: &[ObjDataDiff]) -> Vec<Vec<ObjDataDiff>> {
     split_diffs
 }
 
+#[derive(Clone, Copy)]
+struct SectionDiffContext<'a> {
+    obj: &'a ObjInfo,
+    diff: &'a ObjDiff,
+    section_index: Option<usize>,
+}
+
+impl<'a> SectionDiffContext<'a> {
+    pub fn new(obj: Option<&'a (ObjInfo, ObjDiff)>, section_name: Option<&str>) -> Option<Self> {
+        obj.map(|(obj, diff)| Self {
+            obj,
+            diff,
+            section_index: section_name.and_then(|section_name| find_section(obj, section_name)),
+        })
+    }
+
+    #[inline]
+    pub fn has_section(&self) -> bool { self.section_index.is_some() }
+}
+
 fn data_table_ui(
-    table: TableBuilder<'_>,
+    ui: &mut egui::Ui,
-    left_obj: Option<&(ObjInfo, ObjDiff)>,
+    available_width: f32,
-    right_obj: Option<&(ObjInfo, ObjDiff)>,
+    left_ctx: Option<SectionDiffContext<'_>>,
-    selected_symbol: &SymbolRefByName,
+    right_ctx: Option<SectionDiffContext<'_>>,
     config: &Appearance,
 ) -> Option<()> {
-    let left_section = left_obj.and_then(|(obj, diff)| {
+    let left_section = left_ctx
-        find_section(obj, selected_symbol).map(|i| (&obj.sections[i], &diff.sections[i]))
+        .and_then(|ctx| ctx.section_index.map(|i| (&ctx.obj.sections[i], &ctx.diff.sections[i])));
-    });
+    let right_section = right_ctx
-    let right_section = right_obj.and_then(|(obj, diff)| {
+        .and_then(|ctx| ctx.section_index.map(|i| (&ctx.obj.sections[i], &ctx.diff.sections[i])));
-        find_section(obj, selected_symbol).map(|i| (&obj.sections[i], &diff.sections[i]))
-    });
-
     let total_bytes = left_section
         .or(right_section)?
         .1
@@ -159,72 +176,78 @@ fn data_table_ui(
     let left_diffs = left_section.map(|(_, section)| split_diffs(&section.data_diff));
     let right_diffs = right_section.map(|(_, section)| split_diffs(&section.data_diff));
 
-    table.body(|body| {
+    render_table(ui, available_width, 2, config.code_font.size, total_rows, |row, column| {
-        body.rows(config.code_font.size, total_rows, |mut row| {
+        let i = row.index();
-            let row_index = row.index();
+        let address = i * BYTES_PER_ROW;
-            let address = row_index * BYTES_PER_ROW;
         row.col(|ui| {
+            if column == 0 {
                 if let Some(left_diffs) = &left_diffs {
-                    data_row_ui(ui, address, &left_diffs[row_index], config);
+                    data_row_ui(ui, address, &left_diffs[i], config);
                 }
-            });
+            } else if column == 1 {
-            row.col(|ui| {
                 if let Some(right_diffs) = &right_diffs {
-                    data_row_ui(ui, address, &right_diffs[row_index], config);
+                    data_row_ui(ui, address, &right_diffs[i], config);
+                }
             }
-            });
         });
     });
     Some(())
 }
 
-pub fn data_diff_ui(ui: &mut egui::Ui, state: &mut DiffViewState, appearance: &Appearance) {
+#[must_use]
-    let (Some(result), Some(selected_symbol)) = (&state.build, &state.symbol_state.selected_symbol)
+pub fn data_diff_ui(
-    else {
+    ui: &mut egui::Ui,
-        return;
+    state: &DiffViewState,
+    appearance: &Appearance,
+) -> Option<DiffViewAction> {
+    let mut ret = None;
+    let Some(result) = &state.build else {
+        return ret;
     };
 
+    let section_name =
+        state.symbol_state.left_symbol.as_ref().and_then(|s| s.section_name.as_deref()).or_else(
+            || state.symbol_state.right_symbol.as_ref().and_then(|s| s.section_name.as_deref()),
+        );
+    let left_ctx = SectionDiffContext::new(result.first_obj.as_ref(), section_name);
+    let right_ctx = SectionDiffContext::new(result.second_obj.as_ref(), section_name);
+
+    // If both sides are missing a symbol, switch to symbol diff view
+    if !right_ctx.map_or(false, |ctx| ctx.has_section())
+        && !left_ctx.map_or(false, |ctx| ctx.has_section())
+    {
+        return Some(DiffViewAction::Navigate(DiffViewNavigation::symbol_diff()));
+    }
+
     // Header
     let available_width = ui.available_width();
-    let column_width = available_width / 2.0;
+    render_header(ui, available_width, 2, |ui, column| {
-    ui.allocate_ui_with_layout(
+        if column == 0 {
-        Vec2 { x: available_width, y: 100.0 },
-        Layout::left_to_right(Align::Min),
-        |ui| {
-            ui.style_mut().wrap_mode = Some(egui::TextWrapMode::Truncate);
-
             // Left column
-            ui.allocate_ui_with_layout(
-                Vec2 { x: column_width, y: 100.0 },
-                Layout::top_down(Align::Min),
-                |ui| {
-                    ui.set_width(column_width);
-
             if ui.button("⏴ Back").clicked() {
-                        state.current_view = View::SymbolDiff;
+                ret = Some(DiffViewAction::Navigate(DiffViewNavigation::symbol_diff()));
             }
 
-                    ui.scope(|ui| {
+            if let Some(section) =
-                        ui.style_mut().override_text_style = Some(egui::TextStyle::Monospace);
+                left_ctx.and_then(|ctx| ctx.section_index.map(|i| &ctx.obj.sections[i]))
-                        ui.colored_label(appearance.highlight_color, &selected_symbol.symbol_name);
-                        ui.label("Diff target:");
-                    });
-                },
-            );
-
-            // Right column
-            ui.allocate_ui_with_layout(
-                Vec2 { x: column_width, y: 100.0 },
-                Layout::top_down(Align::Min),
-                |ui| {
-                    ui.set_width(column_width);
-
-                    ui.horizontal(|ui| {
-                        if ui
-                            .add_enabled(!state.build_running, egui::Button::new("Build"))
-                            .clicked()
             {
-                            state.queue_build = true;
+                ui.label(
+                    RichText::new(section.name.clone())
+                        .font(appearance.code_font.clone())
+                        .color(appearance.highlight_color),
+                );
+            } else {
+                ui.label(
+                    RichText::new("Missing")
+                        .font(appearance.code_font.clone())
+                        .color(appearance.replace_color),
+                );
+            }
+        } else if column == 1 {
+            // Right column
+            ui.horizontal(|ui| {
+                if ui.add_enabled(!state.build_running, egui::Button::new("Build")).clicked() {
+                    ret = Some(DiffViewAction::Build);
                 }
                 ui.scope(|ui| {
                     ui.style_mut().override_text_style = Some(egui::TextStyle::Monospace);
@@ -232,45 +255,38 @@ pub fn data_diff_ui(ui: &mut egui::Ui, state: &mut DiffViewState, appearance: &A
                         ui.colored_label(appearance.replace_color, "Building…");
                     } else {
                         ui.label("Last built:");
-                                let format =
+                        let format = format_description::parse("[hour]:[minute]:[second]").unwrap();
-                                    format_description::parse("[hour]:[minute]:[second]").unwrap();
                         ui.label(
-                                    result
+                            result.time.to_offset(appearance.utc_offset).format(&format).unwrap(),
-                                        .time
-                                        .to_offset(appearance.utc_offset)
-                                        .format(&format)
-                                        .unwrap(),
                         );
                     }
                 });
             });
 
-                    ui.scope(|ui| {
+            if let Some(section) =
-                        ui.style_mut().override_text_style = Some(egui::TextStyle::Monospace);
+                right_ctx.and_then(|ctx| ctx.section_index.map(|i| &ctx.obj.sections[i]))
-                        ui.label("");
+            {
-                        ui.label("Diff base:");
+                ui.label(
+                    RichText::new(section.name.clone())
+                        .font(appearance.code_font.clone())
+                        .color(appearance.highlight_color),
+                );
+            } else {
+                ui.label(
+                    RichText::new("Missing")
+                        .font(appearance.code_font.clone())
+                        .color(appearance.replace_color),
+                );
+            }
+        }
     });
-                },
-            );
-        },
-    );
-    ui.separator();
 
     // Table
-    ui.style_mut().interaction.selectable_labels = false;
+    let id =
-    let available_height = ui.available_height();
+        Id::new(state.symbol_state.left_symbol.as_ref().and_then(|s| s.section_name.as_deref()))
-    let table = TableBuilder::new(ui)
+            .with(state.symbol_state.right_symbol.as_ref().and_then(|s| s.section_name.as_deref()));
-        .striped(false)
+    ui.push_id(id, |ui| {
-        .cell_layout(Layout::left_to_right(Align::Min))
+        data_table_ui(ui, available_width, left_ctx, right_ctx, appearance);
-        .columns(Column::exact(column_width).clip(true), 2)
+    });
-        .resizable(false)
+    ret
-        .auto_shrink([false, false])
-        .min_scrolled_height(available_height);
-    data_table_ui(
-        table,
-        result.first_obj.as_ref(),
-        result.second_obj.as_ref(),
-        selected_symbol,
-        appearance,
-    );
 }

objdiff-gui/src/views/extab_diff.rs

@@ -1,28 +1,20 @@
-use egui::{Align, Layout, ScrollArea, Ui, Vec2};
+use egui::{RichText, ScrollArea};
-use egui_extras::{Size, StripBuilder};
 use objdiff_core::{
     arch::ppc::ExceptionInfo,
-    diff::ObjDiff,
+    obj::{ObjInfo, ObjSymbol},
-    obj::{ObjInfo, ObjSymbol, SymbolRef},
 };
 use time::format_description;
 
 use crate::views::{
     appearance::Appearance,
-    symbol_diff::{match_color_for_symbol, DiffViewState, SymbolRefByName, View},
+    column_layout::{render_header, render_strips},
+    function_diff::FunctionDiffContext,
+    symbol_diff::{
+        match_color_for_symbol, DiffViewAction, DiffViewNavigation, DiffViewState, SymbolRefByName,
+        View,
+    },
 };
 
-fn find_symbol(obj: &ObjInfo, selected_symbol: &SymbolRefByName) -> Option<SymbolRef> {
-    for (section_idx, section) in obj.sections.iter().enumerate() {
-        for (symbol_idx, symbol) in section.symbols.iter().enumerate() {
-            if symbol.name == selected_symbol.symbol_name {
-                return Some(SymbolRef { section_idx, symbol_idx });
-            }
-        }
-    }
-    None
-}
-
 fn decode_extab(extab: &ExceptionInfo) -> String {
     let mut text = String::from("");
 
@@ -48,14 +40,12 @@ fn find_extab_entry<'a>(obj: &'a ObjInfo, symbol: &ObjSymbol) -> Option<&'a Exce
 }
 
 fn extab_text_ui(
-    ui: &mut Ui,
+    ui: &mut egui::Ui,
-    obj: &(ObjInfo, ObjDiff),
+    ctx: FunctionDiffContext<'_>,
-    symbol_ref: SymbolRef,
+    symbol: &ObjSymbol,
     appearance: &Appearance,
 ) -> Option<()> {
-    let (_section, symbol) = obj.0.section_symbol(symbol_ref);
+    if let Some(extab_entry) = find_extab_entry(ctx.obj, symbol) {
-
-    if let Some(extab_entry) = find_extab_entry(&obj.0, symbol) {
         let text = decode_extab(extab_entry);
         ui.colored_label(appearance.replace_color, &text);
         return Some(());
@@ -65,79 +55,131 @@ fn extab_text_ui(
 }
 
 fn extab_ui(
-    ui: &mut Ui,
+    ui: &mut egui::Ui,
-    obj: Option<&(ObjInfo, ObjDiff)>,
+    ctx: FunctionDiffContext<'_>,
-    selected_symbol: &SymbolRefByName,
     appearance: &Appearance,
-    _left: bool,
+    _column: usize,
 ) {
     ScrollArea::both().auto_shrink([false, false]).show(ui, |ui| {
         ui.scope(|ui| {
             ui.style_mut().override_text_style = Some(egui::TextStyle::Monospace);
             ui.style_mut().wrap_mode = Some(egui::TextWrapMode::Extend);
 
-            let symbol = obj.and_then(|(obj, _)| find_symbol(obj, selected_symbol));
+            if let Some((_section, symbol)) =
-
+                ctx.symbol_ref.map(|symbol_ref| ctx.obj.section_symbol(symbol_ref))
-            if let (Some(object), Some(symbol_ref)) = (obj, symbol) {
+            {
-                extab_text_ui(ui, object, symbol_ref, appearance);
+                extab_text_ui(ui, ctx, symbol, appearance);
             }
         });
     });
 }
 
-pub fn extab_diff_ui(ui: &mut egui::Ui, state: &mut DiffViewState, appearance: &Appearance) {
+#[must_use]
-    let (Some(result), Some(selected_symbol)) = (&state.build, &state.symbol_state.selected_symbol)
+pub fn extab_diff_ui(
-    else {
+    ui: &mut egui::Ui,
-        return;
+    state: &DiffViewState,
+    appearance: &Appearance,
+) -> Option<DiffViewAction> {
+    let mut ret = None;
+    let Some(result) = &state.build else {
+        return ret;
     };
 
+    let mut left_ctx = FunctionDiffContext::new(
+        result.first_obj.as_ref(),
+        state.symbol_state.left_symbol.as_ref(),
+    );
+    let mut right_ctx = FunctionDiffContext::new(
+        result.second_obj.as_ref(),
+        state.symbol_state.right_symbol.as_ref(),
+    );
+
+    // If one side is missing a symbol, but the diff process found a match, use that symbol
+    let left_diff_symbol = left_ctx.and_then(|ctx| {
+        ctx.symbol_ref.and_then(|symbol_ref| ctx.diff.symbol_diff(symbol_ref).target_symbol)
+    });
+    let right_diff_symbol = right_ctx.and_then(|ctx| {
+        ctx.symbol_ref.and_then(|symbol_ref| ctx.diff.symbol_diff(symbol_ref).target_symbol)
+    });
+    if left_diff_symbol.is_some() && right_ctx.map_or(false, |ctx| !ctx.has_symbol()) {
+        let (right_section, right_symbol) =
+            right_ctx.unwrap().obj.section_symbol(left_diff_symbol.unwrap());
+        let symbol_ref = SymbolRefByName::new(right_symbol, right_section);
+        right_ctx = FunctionDiffContext::new(result.second_obj.as_ref(), Some(&symbol_ref));
+        ret = Some(DiffViewAction::Navigate(DiffViewNavigation {
+            view: Some(View::FunctionDiff),
+            left_symbol: state.symbol_state.left_symbol.clone(),
+            right_symbol: Some(symbol_ref),
+        }));
+    } else if right_diff_symbol.is_some() && left_ctx.map_or(false, |ctx| !ctx.has_symbol()) {
+        let (left_section, left_symbol) =
+            left_ctx.unwrap().obj.section_symbol(right_diff_symbol.unwrap());
+        let symbol_ref = SymbolRefByName::new(left_symbol, left_section);
+        left_ctx = FunctionDiffContext::new(result.first_obj.as_ref(), Some(&symbol_ref));
+        ret = Some(DiffViewAction::Navigate(DiffViewNavigation {
+            view: Some(View::FunctionDiff),
+            left_symbol: Some(symbol_ref),
+            right_symbol: state.symbol_state.right_symbol.clone(),
+        }));
+    }
+
+    // If both sides are missing a symbol, switch to symbol diff view
+    if right_ctx.map_or(false, |ctx| !ctx.has_symbol())
+        && left_ctx.map_or(false, |ctx| !ctx.has_symbol())
+    {
+        return Some(DiffViewAction::Navigate(DiffViewNavigation::symbol_diff()));
+    }
+
     // Header
     let available_width = ui.available_width();
-    let column_width = available_width / 2.0;
+    render_header(ui, available_width, 2, |ui, column| {
-    ui.allocate_ui_with_layout(
+        if column == 0 {
-        Vec2 { x: available_width, y: 100.0 },
-        Layout::left_to_right(Align::Min),
-        |ui| {
-            ui.style_mut().wrap_mode = Some(egui::TextWrapMode::Truncate);
-
             // Left column
-            ui.allocate_ui_with_layout(
-                Vec2 { x: column_width, y: 100.0 },
-                Layout::top_down(Align::Min),
-                |ui| {
-                    ui.set_width(column_width);
-
             ui.horizontal(|ui| {
                 if ui.button("⏴ Back").clicked() {
-                            state.current_view = View::SymbolDiff;
+                    ret = Some(DiffViewAction::Navigate(DiffViewNavigation::symbol_diff()));
+                }
+                ui.separator();
+                if ui
+                    .add_enabled(
+                        !state.scratch_running
+                            && state.scratch_available
+                            && left_ctx.map_or(false, |ctx| ctx.has_symbol()),
+                        egui::Button::new("📲 decomp.me"),
+                    )
+                    .on_hover_text_at_pointer("Create a new scratch on decomp.me (beta)")
+                    .on_disabled_hover_text("Scratch configuration missing")
+                    .clicked()
+                {
+                    if let Some((_section, symbol)) = left_ctx.and_then(|ctx| {
+                        ctx.symbol_ref.map(|symbol_ref| ctx.obj.section_symbol(symbol_ref))
+                    }) {
+                        ret = Some(DiffViewAction::CreateScratch(symbol.name.clone()));
+                    }
                 }
             });
 
-                    let name = selected_symbol
+            if let Some((_section, symbol)) = left_ctx
-                        .demangled_symbol_name
+                .and_then(|ctx| ctx.symbol_ref.map(|symbol_ref| ctx.obj.section_symbol(symbol_ref)))
-                        .as_deref()
-                        .unwrap_or(&selected_symbol.symbol_name);
-                    ui.scope(|ui| {
-                        ui.style_mut().override_text_style = Some(egui::TextStyle::Monospace);
-                        ui.colored_label(appearance.highlight_color, name);
-                        ui.label("Diff target:");
-                    });
-                },
-            );
-
-            // Right column
-            ui.allocate_ui_with_layout(
-                Vec2 { x: column_width, y: 100.0 },
-                Layout::top_down(Align::Min),
-                |ui| {
-                    ui.set_width(column_width);
-
-                    ui.horizontal(|ui| {
-                        if ui
-                            .add_enabled(!state.build_running, egui::Button::new("Build"))
-                            .clicked()
             {
-                            state.queue_build = true;
+                let name = symbol.demangled_name.as_deref().unwrap_or(&symbol.name);
+                ui.label(
+                    RichText::new(name)
+                        .font(appearance.code_font.clone())
+                        .color(appearance.highlight_color),
+                );
+            } else {
+                ui.label(
+                    RichText::new("Missing")
+                        .font(appearance.code_font.clone())
+                        .color(appearance.replace_color),
+                );
+            }
+        } else if column == 1 {
+            // Right column
+            ui.horizontal(|ui| {
+                if ui.add_enabled(!state.build_running, egui::Button::new("Build")).clicked() {
+                    ret = Some(DiffViewAction::Build);
                 }
                 ui.scope(|ui| {
                     ui.style_mut().override_text_style = Some(egui::TextStyle::Monospace);
@@ -145,57 +187,62 @@ pub fn extab_diff_ui(ui: &mut egui::Ui, state: &mut DiffViewState, appearance: &
                         ui.colored_label(appearance.replace_color, "Building…");
                     } else {
                         ui.label("Last built:");
-                                let format =
+                        let format = format_description::parse("[hour]:[minute]:[second]").unwrap();
-                                    format_description::parse("[hour]:[minute]:[second]").unwrap();
                         ui.label(
-                                    result
+                            result.time.to_offset(appearance.utc_offset).format(&format).unwrap(),
-                                        .time
-                                        .to_offset(appearance.utc_offset)
-                                        .format(&format)
-                                        .unwrap(),
                         );
                     }
                 });
+                ui.separator();
+                if ui
+                    .add_enabled(state.source_path_available, egui::Button::new("🖹 Source file"))
+                    .on_hover_text_at_pointer("Open the source file in the default editor")
+                    .on_disabled_hover_text("Source file metadata missing")
+                    .clicked()
+                {
+                    ret = Some(DiffViewAction::OpenSourcePath);
+                }
             });
 
-                    ui.scope(|ui| {
+            if let Some(((_section, symbol), symbol_diff)) = right_ctx.and_then(|ctx| {
-                        ui.style_mut().override_text_style = Some(egui::TextStyle::Monospace);
+                ctx.symbol_ref.map(|symbol_ref| {
-                        if let Some(match_percent) = result
+                    (ctx.obj.section_symbol(symbol_ref), ctx.diff.symbol_diff(symbol_ref))
-                            .second_obj
-                            .as_ref()
-                            .and_then(|(obj, diff)| {
-                                find_symbol(obj, selected_symbol).map(|sref| {
-                                    &diff.sections[sref.section_idx].symbols[sref.symbol_idx]
                 })
-                            })
+            }) {
-                            .and_then(|symbol| symbol.match_percent)
+                let name = symbol.demangled_name.as_deref().unwrap_or(&symbol.name);
-                        {
+                ui.label(
-                            ui.colored_label(
+                    RichText::new(name)
-                                match_color_for_symbol(match_percent, appearance),
+                        .font(appearance.code_font.clone())
-                                format!("{match_percent:.0}%"),
+                        .color(appearance.highlight_color),
+                );
+                if let Some(match_percent) = symbol_diff.match_percent {
+                    ui.label(
+                        RichText::new(format!("{:.0}%", match_percent.floor()))
+                            .font(appearance.code_font.clone())
+                            .color(match_color_for_symbol(match_percent, appearance)),
                     );
-                        } else {
-                            ui.colored_label(appearance.replace_color, "Missing");
                 }
-                        ui.label("Diff base:");
+            } else {
+                ui.label(
+                    RichText::new("Missing")
+                        .font(appearance.code_font.clone())
+                        .color(appearance.replace_color),
+                );
+            }
+        }
     });
-                },
-            );
-        },
-    );
-    ui.separator();
 
     // Table
-    StripBuilder::new(ui).size(Size::remainder()).vertical(|mut strip| {
+    render_strips(ui, available_width, 2, |ui, column| {
-        strip.strip(|builder| {
+        if column == 0 {
-            builder.sizes(Size::remainder(), 2).horizontal(|mut strip| {
+            if let Some(ctx) = left_ctx {
-                strip.cell(|ui| {
+                extab_ui(ui, ctx, appearance, column);
-                    extab_ui(ui, result.first_obj.as_ref(), selected_symbol, appearance, true);
+            }
-                });
+        } else if column == 1 {
-                strip.cell(|ui| {
+            if let Some(ctx) = right_ctx {
-                    extab_ui(ui, result.second_obj.as_ref(), selected_symbol, appearance, false);
+                extab_ui(ui, ctx, appearance, column);
-                });
+            }
-            });
+        }
-        });
     });
+    ret
 }

objdiff-gui/src/views/function_diff.rs

@@ -1,28 +1,28 @@
 use std::default::Default;
 
-use egui::{text::LayoutJob, Align, Label, Layout, Response, Sense, Vec2, Widget};
+use egui::{text::LayoutJob, Id, Label, Response, RichText, Sense, Widget};
-use egui_extras::{Column, TableBuilder, TableRow};
+use egui_extras::TableRow;
 use objdiff_core::{
-    arch::ObjArch,
     diff::{
         display::{display_diff, DiffText, HighlightKind},
         ObjDiff, ObjInsDiff, ObjInsDiffKind,
     },
-    obj::{ObjInfo, ObjIns, ObjInsArg, ObjInsArgValue, ObjSection, ObjSymbol, SymbolRef},
+    obj::{
+        ObjInfo, ObjIns, ObjInsArg, ObjInsArgValue, ObjSection, ObjSectionKind, ObjSymbol,
+        SymbolRef,
+    },
 };
 use time::format_description;
 
 use crate::views::{
     appearance::Appearance,
-    symbol_diff::{match_color_for_symbol, DiffViewState, SymbolRefByName, View},
+    column_layout::{render_header, render_strips, render_table},
+    symbol_diff::{
+        match_color_for_symbol, symbol_list_ui, DiffViewAction, DiffViewNavigation, DiffViewState,
+        SymbolDiffContext, SymbolFilter, SymbolRefByName, SymbolViewState, View,
+    },
 };
 
-#[derive(Copy, Clone, Eq, PartialEq)]
-enum ColumnId {
-    Left,
-    Right,
-}
-
 #[derive(Default)]
 pub struct FunctionViewState {
     left_highlight: HighlightKind,
@@ -30,16 +30,17 @@ pub struct FunctionViewState {
 }
 
 impl FunctionViewState {
-    fn highlight(&self, column: ColumnId) -> &HighlightKind {
+    pub fn highlight(&self, column: usize) -> &HighlightKind {
         match column {
-            ColumnId::Left => &self.left_highlight,
+            0 => &self.left_highlight,
-            ColumnId::Right => &self.right_highlight,
+            1 => &self.right_highlight,
+            _ => &HighlightKind::None,
         }
     }
 
-    fn set_highlight(&mut self, column: ColumnId, highlight: HighlightKind) {
+    pub fn set_highlight(&mut self, column: usize, highlight: HighlightKind) {
         match column {
-            ColumnId::Left => {
+            0 => {
                 if highlight == self.left_highlight {
                     if highlight == self.right_highlight {
                         self.left_highlight = HighlightKind::None;
@@ -51,7 +52,7 @@ impl FunctionViewState {
                     self.left_highlight = highlight;
                 }
             }
-            ColumnId::Right => {
+            1 => {
                 if highlight == self.right_highlight {
                     if highlight == self.left_highlight {
                         self.left_highlight = HighlightKind::None;
@@ -63,13 +64,19 @@ impl FunctionViewState {
                     self.right_highlight = highlight;
                 }
             }
+            _ => {}
         }
     }
+
+    pub fn clear_highlight(&mut self) {
+        self.left_highlight = HighlightKind::None;
+        self.right_highlight = HighlightKind::None;
+    }
 }
 
 fn ins_hover_ui(
     ui: &mut egui::Ui,
-    arch: &dyn ObjArch,
+    obj: &ObjInfo,
     section: &ObjSection,
     ins: &ObjIns,
     symbol: &ObjSymbol,
@@ -112,10 +119,17 @@ fn ins_hover_ui(
         }
 
         if let Some(reloc) = &ins.reloc {
-            ui.label(format!("Relocation type: {}", arch.display_reloc(reloc.flags)));
+            ui.label(format!("Relocation type: {}", obj.arch.display_reloc(reloc.flags)));
             ui.colored_label(appearance.highlight_color, format!("Name: {}", reloc.target.name));
-            if let Some(section) = &reloc.target_section {
+            if let Some(orig_section_index) = reloc.target.orig_section_index {
-                ui.colored_label(appearance.highlight_color, format!("Section: {section}"));
+                if let Some(section) =
+                    obj.sections.iter().find(|s| s.orig_index == orig_section_index)
+                {
+                    ui.colored_label(
+                        appearance.highlight_color,
+                        format!("Section: {}", section.name),
+                    );
+                }
                 ui.colored_label(
                     appearance.highlight_color,
                     format!("Address: {:x}", reloc.target.address),
@@ -124,9 +138,10 @@ fn ins_hover_ui(
                     appearance.highlight_color,
                     format!("Size: {:x}", reloc.target.size),
                 );
-                if let Some(s) = arch
+                if let Some(s) = obj
+                    .arch
                     .guess_data_type(ins)
-                    .and_then(|ty| arch.display_data_type(ty, &reloc.target.bytes))
+                    .and_then(|ty| obj.arch.display_data_type(ty, &reloc.target.bytes))
                 {
                     ui.colored_label(appearance.highlight_color, s);
                 }
@@ -218,17 +233,19 @@ fn find_symbol(obj: &ObjInfo, selected_symbol: &SymbolRefByName) -> Option<Symbo
     None
 }
 
-#[allow(clippy::too_many_arguments)]
+#[must_use]
+#[expect(clippy::too_many_arguments)]
 fn diff_text_ui(
     ui: &mut egui::Ui,
     text: DiffText<'_>,
     ins_diff: &ObjInsDiff,
     appearance: &Appearance,
-    ins_view_state: &mut FunctionViewState,
+    ins_view_state: &FunctionViewState,
-    column: ColumnId,
+    column: usize,
     space_width: f32,
     response_cb: impl Fn(Response) -> Response,
-) {
+) -> Option<DiffViewAction> {
+    let mut ret = None;
     let label_text;
     let mut base_color = match ins_diff.kind {
         ObjInsDiffKind::None | ObjInsDiffKind::OpMismatch | ObjInsDiffKind::ArgMismatch => {
@@ -282,7 +299,7 @@ fn diff_text_ui(
         }
         DiffText::Spacing(n) => {
             ui.add_space(n as f32 * space_width);
-            return;
+            return ret;
         }
         DiffText::Eol => {
             label_text = "\n".to_string();
@@ -299,22 +316,25 @@ fn diff_text_ui(
     .ui(ui);
     response = response_cb(response);
     if response.clicked() {
-        ins_view_state.set_highlight(column, text.into());
+        ret = Some(DiffViewAction::SetDiffHighlight(column, text.into()));
     }
     if len < pad_to {
         ui.add_space((pad_to - len) as f32 * space_width);
     }
+    ret
 }
 
+#[must_use]
 fn asm_row_ui(
     ui: &mut egui::Ui,
     ins_diff: &ObjInsDiff,
     symbol: &ObjSymbol,
     appearance: &Appearance,
-    ins_view_state: &mut FunctionViewState,
+    ins_view_state: &FunctionViewState,
-    column: ColumnId,
+    column: usize,
     response_cb: impl Fn(Response) -> Response,
-) {
+) -> Option<DiffViewAction> {
+    let mut ret = None;
     ui.spacing_mut().item_spacing.x = 0.0;
     ui.style_mut().wrap_mode = Some(egui::TextWrapMode::Extend);
     if ins_diff.kind != ObjInsDiffKind::None {
@@ -322,7 +342,7 @@ fn asm_row_ui(
     }
     let space_width = ui.fonts(|f| f.glyph_width(&appearance.code_font, ' '));
     display_diff(ins_diff, symbol.address, |text| {
-        diff_text_ui(
+        if let Some(action) = diff_text_ui(
             ui,
             text,
             ins_diff,
@@ -331,166 +351,385 @@ fn asm_row_ui(
             column,
             space_width,
             &response_cb,
-        );
+        ) {
+            ret = Some(action);
+        }
         Ok::<_, ()>(())
     })
     .unwrap();
+    ret
 }
 
+#[must_use]
 fn asm_col_ui(
     row: &mut TableRow<'_, '_>,
-    obj: &(ObjInfo, ObjDiff),
+    ctx: FunctionDiffContext<'_>,
-    symbol_ref: SymbolRef,
     appearance: &Appearance,
-    ins_view_state: &mut FunctionViewState,
+    ins_view_state: &FunctionViewState,
-    column: ColumnId,
+    column: usize,
-) {
+) -> Option<DiffViewAction> {
-    let (section, symbol) = obj.0.section_symbol(symbol_ref);
+    let mut ret = None;
-    let section = section.unwrap();
+    let symbol_ref = ctx.symbol_ref?;
-    let ins_diff = &obj.1.symbol_diff(symbol_ref).instructions[row.index()];
+    let (section, symbol) = ctx.obj.section_symbol(symbol_ref);
+    let section = section?;
+    let ins_diff = &ctx.diff.symbol_diff(symbol_ref).instructions[row.index()];
     let response_cb = |response: Response| {
         if let Some(ins) = &ins_diff.ins {
             response.context_menu(|ui| ins_context_menu(ui, section, ins, symbol));
             response.on_hover_ui_at_pointer(|ui| {
-                ins_hover_ui(ui, obj.0.arch.as_ref(), section, ins, symbol, appearance)
+                ins_hover_ui(ui, ctx.obj, section, ins, symbol, appearance)
             })
         } else {
             response
         }
     };
     let (_, response) = row.col(|ui| {
-        asm_row_ui(ui, ins_diff, symbol, appearance, ins_view_state, column, response_cb);
+        if let Some(action) =
+            asm_row_ui(ui, ins_diff, symbol, appearance, ins_view_state, column, response_cb)
+        {
+            ret = Some(action);
+        }
     });
     response_cb(response);
+    ret
 }
 
-fn empty_col_ui(row: &mut TableRow<'_, '_>) {
+#[must_use]
-    row.col(|ui| {
-        ui.label("");
-    });
-}
-
 fn asm_table_ui(
-    table: TableBuilder<'_>,
+    ui: &mut egui::Ui,
-    left_obj: Option<&(ObjInfo, ObjDiff)>,
+    available_width: f32,
-    right_obj: Option<&(ObjInfo, ObjDiff)>,
+    left_ctx: Option<FunctionDiffContext<'_>>,
-    selected_symbol: &SymbolRefByName,
+    right_ctx: Option<FunctionDiffContext<'_>>,
     appearance: &Appearance,
-    ins_view_state: &mut FunctionViewState,
+    ins_view_state: &FunctionViewState,
-) -> Option<()> {
+    symbol_state: &SymbolViewState,
-    let left_symbol = left_obj.and_then(|(obj, _)| find_symbol(obj, selected_symbol));
+) -> Option<DiffViewAction> {
-    let right_symbol = right_obj.and_then(|(obj, _)| find_symbol(obj, selected_symbol));
+    let mut ret = None;
-    let instructions_len = match (left_symbol, right_symbol) {
+    let left_len = left_ctx.and_then(|ctx| {
-        (Some(left_symbol_ref), Some(right_symbol_ref)) => {
+        ctx.symbol_ref.map(|symbol_ref| ctx.diff.symbol_diff(symbol_ref).instructions.len())
-            let left_len = left_obj.unwrap().1.symbol_diff(left_symbol_ref).instructions.len();
+    });
-            let right_len = right_obj.unwrap().1.symbol_diff(right_symbol_ref).instructions.len();
+    let right_len = right_ctx.and_then(|ctx| {
-            debug_assert_eq!(left_len, right_len);
+        ctx.symbol_ref.map(|symbol_ref| ctx.diff.symbol_diff(symbol_ref).instructions.len())
+    });
+    let instructions_len = match (left_len, right_len) {
+        (Some(left_len), Some(right_len)) => {
+            if left_len != right_len {
+                ui.label("Instruction count mismatch");
+                return None;
+            }
             left_len
         }
-        (Some(left_symbol_ref), None) => {
+        (Some(left_len), None) => left_len,
-            left_obj.unwrap().1.symbol_diff(left_symbol_ref).instructions.len()
+        (None, Some(right_len)) => right_len,
+        (None, None) => {
+            ui.label("No symbol selected");
+            return None;
         }
-        (None, Some(right_symbol_ref)) => {
-            right_obj.unwrap().1.symbol_diff(right_symbol_ref).instructions.len()
-        }
-        (None, None) => return None,
     };
-    table.body(|body| {
+    if left_len.is_some() && right_len.is_some() {
-        body.rows(appearance.code_font.size, instructions_len, |mut row| {
+        // Joint view
-            if let (Some(left_obj), Some(left_symbol_ref)) = (left_obj, left_symbol) {
+        render_table(
-                asm_col_ui(
+            ui,
-                    &mut row,
+            available_width,
-                    left_obj,
+            2,
+            appearance.code_font.size,
+            instructions_len,
+            |row, column| {
+                if column == 0 {
+                    if let Some(ctx) = left_ctx {
+                        if let Some(action) =
+                            asm_col_ui(row, ctx, appearance, ins_view_state, column)
+                        {
+                            ret = Some(action);
+                        }
+                    }
+                } else if column == 1 {
+                    if let Some(ctx) = right_ctx {
+                        if let Some(action) =
+                            asm_col_ui(row, ctx, appearance, ins_view_state, column)
+                        {
+                            ret = Some(action);
+                        }
+                    }
+                    if row.response().clicked() {
+                        ret = Some(DiffViewAction::ClearDiffHighlight);
+                    }
+                }
+            },
+        );
+    } else {
+        // Split view, one side is the symbol list
+        render_strips(ui, available_width, 2, |ui, column| {
+            if column == 0 {
+                if let Some(ctx) = left_ctx {
+                    if ctx.has_symbol() {
+                        render_table(
+                            ui,
+                            available_width / 2.0,
+                            1,
+                            appearance.code_font.size,
+                            instructions_len,
+                            |row, column| {
+                                if let Some(action) =
+                                    asm_col_ui(row, ctx, appearance, ins_view_state, column)
+                                {
+                                    ret = Some(action);
+                                }
+                                if row.response().clicked() {
+                                    ret = Some(DiffViewAction::ClearDiffHighlight);
+                                }
+                            },
+                        );
+                    } else if let Some((right_ctx, right_symbol_ref)) =
+                        right_ctx.and_then(|ctx| ctx.symbol_ref.map(|symbol_ref| (ctx, symbol_ref)))
+                    {
+                        if let Some(action) = symbol_list_ui(
+                            ui,
+                            SymbolDiffContext { obj: ctx.obj, diff: ctx.diff },
+                            None,
+                            symbol_state,
+                            SymbolFilter::Mapping(right_symbol_ref),
+                            appearance,
+                            column,
+                        ) {
+                            match action {
+                                DiffViewAction::Navigate(DiffViewNavigation {
+                                    left_symbol: Some(left_symbol_ref),
+                                    ..
+                                }) => {
+                                    let (right_section, right_symbol) =
+                                        right_ctx.obj.section_symbol(right_symbol_ref);
+                                    ret = Some(DiffViewAction::SetMapping(
+                                        match right_section.map(|s| s.kind) {
+                                            Some(ObjSectionKind::Code) => View::FunctionDiff,
+                                            _ => View::SymbolDiff,
+                                        },
                                         left_symbol_ref,
-                    appearance,
+                                        SymbolRefByName::new(right_symbol, right_section),
-                    ins_view_state,
+                                    ));
-                    ColumnId::Left,
-                );
-            } else {
-                empty_col_ui(&mut row);
                                 }
-            if let (Some(right_obj), Some(right_symbol_ref)) = (right_obj, right_symbol) {
+                                DiffViewAction::SetSymbolHighlight(_, _) => {
-                asm_col_ui(
+                                    // Ignore
-                    &mut row,
+                                }
-                    right_obj,
+                                _ => {
+                                    ret = Some(action);
+                                }
+                            }
+                        }
+                    }
+                } else {
+                    ui.label("No left object");
+                }
+            } else if column == 1 {
+                if let Some(ctx) = right_ctx {
+                    if ctx.has_symbol() {
+                        render_table(
+                            ui,
+                            available_width / 2.0,
+                            1,
+                            appearance.code_font.size,
+                            instructions_len,
+                            |row, column| {
+                                if let Some(action) =
+                                    asm_col_ui(row, ctx, appearance, ins_view_state, column)
+                                {
+                                    ret = Some(action);
+                                }
+                                if row.response().clicked() {
+                                    ret = Some(DiffViewAction::ClearDiffHighlight);
+                                }
+                            },
+                        );
+                    } else if let Some((left_ctx, left_symbol_ref)) =
+                        left_ctx.and_then(|ctx| ctx.symbol_ref.map(|symbol_ref| (ctx, symbol_ref)))
+                    {
+                        if let Some(action) = symbol_list_ui(
+                            ui,
+                            SymbolDiffContext { obj: ctx.obj, diff: ctx.diff },
+                            None,
+                            symbol_state,
+                            SymbolFilter::Mapping(left_symbol_ref),
+                            appearance,
+                            column,
+                        ) {
+                            match action {
+                                DiffViewAction::Navigate(DiffViewNavigation {
+                                    right_symbol: Some(right_symbol_ref),
+                                    ..
+                                }) => {
+                                    let (left_section, left_symbol) =
+                                        left_ctx.obj.section_symbol(left_symbol_ref);
+                                    ret = Some(DiffViewAction::SetMapping(
+                                        match left_section.map(|s| s.kind) {
+                                            Some(ObjSectionKind::Code) => View::FunctionDiff,
+                                            _ => View::SymbolDiff,
+                                        },
+                                        SymbolRefByName::new(left_symbol, left_section),
                                         right_symbol_ref,
-                    appearance,
+                                    ));
-                    ins_view_state,
+                                }
-                    ColumnId::Right,
+                                DiffViewAction::SetSymbolHighlight(_, _) => {
-                );
+                                    // Ignore
+                                }
+                                _ => {
+                                    ret = Some(action);
+                                }
+                            }
+                        }
+                    }
                 } else {
-                empty_col_ui(&mut row);
+                    ui.label("No right object");
+                }
             }
         });
-    });
+    }
-    Some(())
+    ret
 }
 
-pub fn function_diff_ui(ui: &mut egui::Ui, state: &mut DiffViewState, appearance: &Appearance) {
+#[derive(Clone, Copy)]
-    let (Some(result), Some(selected_symbol)) = (&state.build, &state.symbol_state.selected_symbol)
+pub struct FunctionDiffContext<'a> {
-    else {
+    pub obj: &'a ObjInfo,
-        return;
+    pub diff: &'a ObjDiff,
+    pub symbol_ref: Option<SymbolRef>,
+}
+
+impl<'a> FunctionDiffContext<'a> {
+    pub fn new(
+        obj: Option<&'a (ObjInfo, ObjDiff)>,
+        selected_symbol: Option<&SymbolRefByName>,
+    ) -> Option<Self> {
+        obj.map(|(obj, diff)| Self {
+            obj,
+            diff,
+            symbol_ref: selected_symbol.and_then(|s| find_symbol(obj, s)),
+        })
+    }
+
+    #[inline]
+    pub fn has_symbol(&self) -> bool { self.symbol_ref.is_some() }
+}
+
+#[must_use]
+pub fn function_diff_ui(
+    ui: &mut egui::Ui,
+    state: &DiffViewState,
+    appearance: &Appearance,
+) -> Option<DiffViewAction> {
+    let mut ret = None;
+    let Some(result) = &state.build else {
+        return ret;
     };
 
+    let mut left_ctx = FunctionDiffContext::new(
+        result.first_obj.as_ref(),
+        state.symbol_state.left_symbol.as_ref(),
+    );
+    let mut right_ctx = FunctionDiffContext::new(
+        result.second_obj.as_ref(),
+        state.symbol_state.right_symbol.as_ref(),
+    );
+
+    // If one side is missing a symbol, but the diff process found a match, use that symbol
+    let left_diff_symbol = left_ctx.and_then(|ctx| {
+        ctx.symbol_ref.and_then(|symbol_ref| ctx.diff.symbol_diff(symbol_ref).target_symbol)
+    });
+    let right_diff_symbol = right_ctx.and_then(|ctx| {
+        ctx.symbol_ref.and_then(|symbol_ref| ctx.diff.symbol_diff(symbol_ref).target_symbol)
+    });
+    if left_diff_symbol.is_some() && right_ctx.map_or(false, |ctx| !ctx.has_symbol()) {
+        let (right_section, right_symbol) =
+            right_ctx.unwrap().obj.section_symbol(left_diff_symbol.unwrap());
+        let symbol_ref = SymbolRefByName::new(right_symbol, right_section);
+        right_ctx = FunctionDiffContext::new(result.second_obj.as_ref(), Some(&symbol_ref));
+        ret = Some(DiffViewAction::Navigate(DiffViewNavigation {
+            view: Some(View::FunctionDiff),
+            left_symbol: state.symbol_state.left_symbol.clone(),
+            right_symbol: Some(symbol_ref),
+        }));
+    } else if right_diff_symbol.is_some() && left_ctx.map_or(false, |ctx| !ctx.has_symbol()) {
+        let (left_section, left_symbol) =
+            left_ctx.unwrap().obj.section_symbol(right_diff_symbol.unwrap());
+        let symbol_ref = SymbolRefByName::new(left_symbol, left_section);
+        left_ctx = FunctionDiffContext::new(result.first_obj.as_ref(), Some(&symbol_ref));
+        ret = Some(DiffViewAction::Navigate(DiffViewNavigation {
+            view: Some(View::FunctionDiff),
+            left_symbol: Some(symbol_ref),
+            right_symbol: state.symbol_state.right_symbol.clone(),
+        }));
+    }
+
+    // If both sides are missing a symbol, switch to symbol diff view
+    if right_ctx.map_or(false, |ctx| !ctx.has_symbol())
+        && left_ctx.map_or(false, |ctx| !ctx.has_symbol())
+    {
+        return Some(DiffViewAction::Navigate(DiffViewNavigation::symbol_diff()));
+    }
+
     // Header
     let available_width = ui.available_width();
-    let column_width = available_width / 2.0;
+    render_header(ui, available_width, 2, |ui, column| {
-    ui.allocate_ui_with_layout(
+        if column == 0 {
-        Vec2 { x: available_width, y: 100.0 },
-        Layout::left_to_right(Align::Min),
-        |ui| {
-            ui.style_mut().wrap_mode = Some(egui::TextWrapMode::Truncate);
-
             // Left column
-            ui.allocate_ui_with_layout(
-                Vec2 { x: column_width, y: 100.0 },
-                Layout::top_down(Align::Min),
-                |ui| {
-                    ui.set_width(column_width);
-
             ui.horizontal(|ui| {
                 if ui.button("⏴ Back").clicked() {
-                            state.current_view = View::SymbolDiff;
+                    ret = Some(DiffViewAction::Navigate(DiffViewNavigation::symbol_diff()));
                 }
                 ui.separator();
                 if ui
                     .add_enabled(
-                                !state.scratch_running && state.scratch_available,
+                        !state.scratch_running
+                            && state.scratch_available
+                            && left_ctx.map_or(false, |ctx| ctx.has_symbol()),
                         egui::Button::new("📲 decomp.me"),
                     )
                     .on_hover_text_at_pointer("Create a new scratch on decomp.me (beta)")
                     .on_disabled_hover_text("Scratch configuration missing")
                     .clicked()
                 {
-                            state.queue_scratch = true;
+                    if let Some((_section, symbol)) = left_ctx.and_then(|ctx| {
+                        ctx.symbol_ref.map(|symbol_ref| ctx.obj.section_symbol(symbol_ref))
+                    }) {
+                        ret = Some(DiffViewAction::CreateScratch(symbol.name.clone()));
+                    }
                 }
             });
 
-                    let name = selected_symbol
+            if let Some((_section, symbol)) = left_ctx
-                        .demangled_symbol_name
+                .and_then(|ctx| ctx.symbol_ref.map(|symbol_ref| ctx.obj.section_symbol(symbol_ref)))
-                        .as_deref()
+            {
-                        .unwrap_or(&selected_symbol.symbol_name);
+                let name = symbol.demangled_name.as_deref().unwrap_or(&symbol.name);
-                    ui.scope(|ui| {
+                ui.label(
-                        ui.style_mut().override_text_style = Some(egui::TextStyle::Monospace);
+                    RichText::new(name)
-                        ui.colored_label(appearance.highlight_color, name);
+                        .font(appearance.code_font.clone())
-                        ui.label("Diff target:");
+                        .color(appearance.highlight_color),
-                    });
-                },
                 );
-
+                if right_ctx.map_or(false, |m| m.has_symbol())
-            // Right column
+                    && ui
-            ui.allocate_ui_with_layout(
+                        .button("Change target")
-                Vec2 { x: column_width, y: 100.0 },
+                        .on_hover_text_at_pointer("Choose a different symbol to use as the target")
-                Layout::top_down(Align::Min),
-                |ui| {
-                    ui.set_width(column_width);
-
-                    ui.horizontal(|ui| {
-                        if ui
-                            .add_enabled(!state.build_running, egui::Button::new("Build"))
                         .clicked()
                 {
-                            state.queue_build = true;
+                    if let Some(symbol_ref) = state.symbol_state.right_symbol.as_ref() {
+                        ret = Some(DiffViewAction::SelectingLeft(symbol_ref.clone()));
+                    }
+                }
+            } else {
+                ui.label(
+                    RichText::new("Missing")
+                        .font(appearance.code_font.clone())
+                        .color(appearance.replace_color),
+                );
+                ui.label(
+                    RichText::new("Choose target symbol")
+                        .font(appearance.code_font.clone())
+                        .color(appearance.highlight_color),
+                );
+            }
+        } else if column == 1 {
+            // Right column
+            ui.horizontal(|ui| {
+                if ui.add_enabled(!state.build_running, egui::Button::new("Build")).clicked() {
+                    ret = Some(DiffViewAction::Build);
                 }
                 ui.scope(|ui| {
                     ui.style_mut().override_text_style = Some(egui::TextStyle::Monospace);
@@ -498,74 +737,90 @@ pub fn function_diff_ui(ui: &mut egui::Ui, state: &mut DiffViewState, appearance
                         ui.colored_label(appearance.replace_color, "Building…");
                     } else {
                         ui.label("Last built:");
-                                let format =
+                        let format = format_description::parse("[hour]:[minute]:[second]").unwrap();
-                                    format_description::parse("[hour]:[minute]:[second]").unwrap();
                         ui.label(
-                                    result
+                            result.time.to_offset(appearance.utc_offset).format(&format).unwrap(),
-                                        .time
-                                        .to_offset(appearance.utc_offset)
-                                        .format(&format)
-                                        .unwrap(),
                         );
                     }
                 });
                 ui.separator();
                 if ui
-                            .add_enabled(
+                    .add_enabled(state.source_path_available, egui::Button::new("🖹 Source file"))
-                                state.source_path_available,
-                                egui::Button::new("🖹 Source file"),
-                            )
                     .on_hover_text_at_pointer("Open the source file in the default editor")
                     .on_disabled_hover_text("Source file metadata missing")
                     .clicked()
                 {
-                            state.queue_open_source_path = true;
+                    ret = Some(DiffViewAction::OpenSourcePath);
                 }
             });
 
-                    ui.scope(|ui| {
+            if let Some(((_section, symbol), symbol_diff)) = right_ctx.and_then(|ctx| {
-                        ui.style_mut().override_text_style = Some(egui::TextStyle::Monospace);
+                ctx.symbol_ref.map(|symbol_ref| {
-                        if let Some(match_percent) = result
+                    (ctx.obj.section_symbol(symbol_ref), ctx.diff.symbol_diff(symbol_ref))
-                            .second_obj
-                            .as_ref()
-                            .and_then(|(obj, diff)| {
-                                find_symbol(obj, selected_symbol).map(|sref| {
-                                    &diff.sections[sref.section_idx].symbols[sref.symbol_idx]
                 })
-                            })
+            }) {
-                            .and_then(|symbol| symbol.match_percent)
+                let name = symbol.demangled_name.as_deref().unwrap_or(&symbol.name);
-                        {
+                ui.label(
-                            ui.colored_label(
+                    RichText::new(name)
-                                match_color_for_symbol(match_percent, appearance),
+                        .font(appearance.code_font.clone())
-                                format!("{match_percent:.0}%"),
+                        .color(appearance.highlight_color),
+                );
+                ui.horizontal(|ui| {
+                    if let Some(match_percent) = symbol_diff.match_percent {
+                        ui.label(
+                            RichText::new(format!("{:.0}%", match_percent.floor()))
+                                .font(appearance.code_font.clone())
+                                .color(match_color_for_symbol(match_percent, appearance)),
                         );
-                        } else {
-                            ui.colored_label(appearance.replace_color, "Missing");
                     }
-                        ui.label("Diff base:");
+                    if left_ctx.map_or(false, |m| m.has_symbol()) {
-                    });
-                },
-            );
-        },
-    );
                         ui.separator();
+                        if ui
+                            .button("Change base")
+                            .on_hover_text_at_pointer(
+                                "Choose a different symbol to use as the base",
+                            )
+                            .clicked()
+                        {
+                            if let Some(symbol_ref) = state.symbol_state.left_symbol.as_ref() {
+                                ret = Some(DiffViewAction::SelectingRight(symbol_ref.clone()));
+                            }
+                        }
+                    }
+                });
+            } else {
+                ui.label(
+                    RichText::new("Missing")
+                        .font(appearance.code_font.clone())
+                        .color(appearance.replace_color),
+                );
+                ui.label(
+                    RichText::new("Choose base symbol")
+                        .font(appearance.code_font.clone())
+                        .color(appearance.highlight_color),
+                );
+            }
+        }
+    });
 
     // Table
-    ui.style_mut().interaction.selectable_labels = false;
+    let id = Id::new(state.symbol_state.left_symbol.as_ref().map(|s| s.symbol_name.as_str()))
-    let available_height = ui.available_height();
+        .with(state.symbol_state.right_symbol.as_ref().map(|s| s.symbol_name.as_str()));
-    let table = TableBuilder::new(ui)
+    if let Some(action) = ui
-        .striped(false)
+        .push_id(id, |ui| {
-        .cell_layout(Layout::left_to_right(Align::Min))
-        .columns(Column::exact(column_width).clip(true), 2)
-        .resizable(false)
-        .auto_shrink([false, false])
-        .min_scrolled_height(available_height);
             asm_table_ui(
-        table,
+                ui,
-        result.first_obj.as_ref(),
+                available_width,
-        result.second_obj.as_ref(),
+                left_ctx,
-        selected_symbol,
+                right_ctx,
                 appearance,
-        &mut state.function_state,
+                &state.function_state,
-    );
+                &state.symbol_state,
+            )
+        })
+        .inner
+    {
+        ret = Some(action);
+    }
+    ret
 }

objdiff-gui/src/views/mod.rs

@@ -1,6 +1,7 @@
 use egui::{text::LayoutJob, Color32, FontId, TextFormat};
 
 pub(crate) mod appearance;
+pub(crate) mod column_layout;
 pub(crate) mod config;
 pub(crate) mod data_diff;
 pub(crate) mod debug;

objdiff-gui/src/views/symbol_diff.rs

@@ -1,14 +1,15 @@
-use std::mem::take;
+use std::{collections::BTreeMap, mem::take};
 
 use egui::{
-    text::LayoutJob, Align, CollapsingHeader, Color32, Id, Layout, OpenUrl, ScrollArea,
+    text::LayoutJob, CollapsingHeader, Color32, Id, OpenUrl, ScrollArea, SelectableLabel, TextEdit,
-    SelectableLabel, TextEdit, Ui, Vec2, Widget,
+    Ui, Widget,
 };
-use egui_extras::{Size, StripBuilder};
 use objdiff_core::{
     arch::ObjArch,
-    diff::{ObjDiff, ObjSymbolDiff},
+    diff::{display::HighlightKind, ObjDiff, ObjSymbolDiff},
-    obj::{ObjInfo, ObjSection, ObjSectionKind, ObjSymbol, ObjSymbolFlags, SymbolRef},
+    obj::{
+        ObjInfo, ObjSection, ObjSectionKind, ObjSymbol, ObjSymbolFlags, SymbolRef, SECTION_COMMON,
+    },
 };
 use regex::{Regex, RegexBuilder};
 
@@ -19,17 +20,28 @@ use crate::{
         objdiff::{BuildStatus, ObjDiffResult},
         Job, JobQueue, JobResult,
     },
-    views::{appearance::Appearance, function_diff::FunctionViewState, write_text},
+    views::{
+        appearance::Appearance,
+        column_layout::{render_header, render_strips},
+        function_diff::FunctionViewState,
+        write_text,
+    },
 };
 
+#[derive(Debug, Clone)]
 pub struct SymbolRefByName {
     pub symbol_name: String,
-    pub demangled_symbol_name: Option<String>,
+    pub section_name: Option<String>,
-    pub section_name: String,
 }
 
-#[allow(clippy::enum_variant_names)]
+impl SymbolRefByName {
-#[derive(Default, Eq, PartialEq, Copy, Clone)]
+    pub fn new(symbol: &ObjSymbol, section: Option<&ObjSection>) -> Self {
+        Self { symbol_name: symbol.name.clone(), section_name: section.map(|s| s.name.clone()) }
+    }
+}
+
+#[expect(clippy::enum_variant_names)]
+#[derive(Debug, Default, Eq, PartialEq, Copy, Clone, Hash)]
 pub enum View {
     #[default]
     SymbolDiff,
@@ -38,6 +50,71 @@ pub enum View {
     ExtabDiff,
 }
 
+#[derive(Debug, Clone)]
+pub enum DiffViewAction {
+    /// Queue a rebuild of the current object(s)
+    Build,
+    /// Navigate to a new diff view
+    Navigate(DiffViewNavigation),
+    /// Set the highlighted symbols in the symbols view
+    SetSymbolHighlight(Option<SymbolRef>, Option<SymbolRef>),
+    /// Set the symbols view search filter
+    SetSearch(String),
+    /// Submit the current function to decomp.me
+    CreateScratch(String),
+    /// Open the source path of the current object
+    OpenSourcePath,
+    /// Set the highlight for a diff column
+    SetDiffHighlight(usize, HighlightKind),
+    /// Clear the highlight for all diff columns
+    ClearDiffHighlight,
+    /// Start selecting a left symbol for mapping.
+    /// The symbol reference is the right symbol to map to.
+    SelectingLeft(SymbolRefByName),
+    /// Start selecting a right symbol for mapping.
+    /// The symbol reference is the left symbol to map to.
+    SelectingRight(SymbolRefByName),
+    /// Set a symbol mapping.
+    SetMapping(View, SymbolRefByName, SymbolRefByName),
+    /// Set the show_mapped_symbols flag
+    SetShowMappedSymbols(bool),
+}
+
+#[derive(Debug, Clone, Default)]
+pub struct DiffViewNavigation {
+    pub view: Option<View>,
+    pub left_symbol: Option<SymbolRefByName>,
+    pub right_symbol: Option<SymbolRefByName>,
+}
+
+impl DiffViewNavigation {
+    pub fn symbol_diff() -> Self {
+        Self { view: Some(View::SymbolDiff), left_symbol: None, right_symbol: None }
+    }
+
+    pub fn with_symbols(
+        view: View,
+        other_ctx: Option<SymbolDiffContext<'_>>,
+        symbol: &ObjSymbol,
+        section: &ObjSection,
+        symbol_diff: &ObjSymbolDiff,
+        column: usize,
+    ) -> Self {
+        let symbol1 = Some(SymbolRefByName::new(symbol, Some(section)));
+        let symbol2 = symbol_diff.target_symbol.and_then(|symbol_ref| {
+            other_ctx.map(|ctx| {
+                let (section, symbol) = ctx.obj.section_symbol(symbol_ref);
+                SymbolRefByName::new(symbol, section)
+            })
+        });
+        match column {
+            0 => Self { view: Some(view), left_symbol: symbol1, right_symbol: symbol2 },
+            1 => Self { view: Some(view), left_symbol: symbol2, right_symbol: symbol1 },
+            _ => unreachable!("Invalid column index"),
+        }
+    }
+}
+
 #[derive(Default)]
 pub struct DiffViewState {
     pub build: Option<Box<ObjDiffResult>>,
@@ -47,22 +124,23 @@ pub struct DiffViewState {
     pub function_state: FunctionViewState,
     pub search: String,
     pub search_regex: Option<Regex>,
-    pub queue_build: bool,
     pub build_running: bool,
     pub scratch_available: bool,
-    pub queue_scratch: bool,
     pub scratch_running: bool,
     pub source_path_available: bool,
-    pub queue_open_source_path: bool,
+    pub post_build_nav: Option<DiffViewNavigation>,
+    pub object_name: String,
 }
 
 #[derive(Default)]
 pub struct SymbolViewState {
     pub highlighted_symbol: (Option<SymbolRef>, Option<SymbolRef>),
-    pub selected_symbol: Option<SymbolRefByName>,
+    pub left_symbol: Option<SymbolRefByName>,
+    pub right_symbol: Option<SymbolRefByName>,
     pub reverse_fn_order: bool,
     pub disable_reverse_fn_order: bool,
     pub show_hidden_symbols: bool,
+    pub show_mapped_symbols: bool,
 }
 
 impl DiffViewState {
@@ -70,6 +148,16 @@ impl DiffViewState {
         jobs.results.retain_mut(|result| match result {
             JobResult::ObjDiff(result) => {
                 self.build = take(result);
+
+                // TODO: where should this go?
+                if let Some(result) = self.post_build_nav.take() {
+                    if let Some(view) = result.view {
+                        self.current_view = view;
+                    }
+                    self.symbol_state.left_symbol = result.left_symbol;
+                    self.symbol_state.right_symbol = result.right_symbol;
+                }
+
                 false
             }
             JobResult::CreateScratch(result) => {
@@ -93,44 +181,103 @@ impl DiffViewState {
                 self.source_path_available = false;
             }
             self.scratch_available = CreateScratchConfig::is_available(&state.config);
+            self.object_name =
+                state.config.selected_obj.as_ref().map(|o| o.name.clone()).unwrap_or_default();
         }
     }
 
-    pub fn post_update(&mut self, ctx: &egui::Context, jobs: &mut JobQueue, state: &AppStateRef) {
+    pub fn post_update(
+        &mut self,
+        action: Option<DiffViewAction>,
+        ctx: &egui::Context,
+        jobs: &mut JobQueue,
+        state: &AppStateRef,
+    ) {
         if let Some(result) = take(&mut self.scratch) {
             ctx.output_mut(|o| o.open_url = Some(OpenUrl::new_tab(result.scratch_url)));
         }
 
-        if self.queue_build {
+        let Some(action) = action else {
-            self.queue_build = false;
+            return;
+        };
+        match action {
+            DiffViewAction::Build => {
                 if let Ok(mut state) = state.write() {
                     state.queue_build = true;
                 }
             }
-
+            DiffViewAction::Navigate(nav) => {
-        if self.queue_scratch {
+                if self.post_build_nav.is_some() {
-            self.queue_scratch = false;
+                    // Ignore action if we're already navigating
-            if let Some(function_name) =
+                    return;
-                self.symbol_state.selected_symbol.as_ref().map(|sym| sym.symbol_name.clone())
+                }
+                self.symbol_state.highlighted_symbol = (None, None);
+                let Ok(mut state) = state.write() else {
+                    return;
+                };
+                if (nav.left_symbol.is_some() && nav.right_symbol.is_some())
+                    || (nav.left_symbol.is_none() && nav.right_symbol.is_none())
+                    || nav.view != Some(View::FunctionDiff)
                 {
-                if let Ok(state) = state.read() {
+                    // Regular navigation
+                    if state.is_selecting_symbol() {
+                        // Cancel selection and reload
+                        state.clear_selection();
+                        self.post_build_nav = Some(nav);
+                    } else {
+                        // Navigate immediately
+                        if let Some(view) = nav.view {
+                            self.current_view = view;
+                        }
+                        self.symbol_state.left_symbol = nav.left_symbol;
+                        self.symbol_state.right_symbol = nav.right_symbol;
+                    }
+                } else {
+                    // Enter selection mode
+                    match (&nav.left_symbol, &nav.right_symbol) {
+                        (Some(left_ref), None) => {
+                            state.set_selecting_right(&left_ref.symbol_name);
+                        }
+                        (None, Some(right_ref)) => {
+                            state.set_selecting_left(&right_ref.symbol_name);
+                        }
+                        (Some(_), Some(_)) => unreachable!(),
+                        (None, None) => unreachable!(),
+                    }
+                    self.post_build_nav = Some(nav);
+                }
+            }
+            DiffViewAction::SetSymbolHighlight(left, right) => {
+                self.symbol_state.highlighted_symbol = (left, right);
+            }
+            DiffViewAction::SetSearch(search) => {
+                self.search_regex = if search.is_empty() {
+                    None
+                } else if let Ok(regex) = RegexBuilder::new(&search).case_insensitive(true).build()
+                {
+                    Some(regex)
+                } else {
+                    None
+                };
+                self.search = search;
+            }
+            DiffViewAction::CreateScratch(function_name) => {
+                let Ok(state) = state.read() else {
+                    return;
+                };
                 match CreateScratchConfig::from_config(&state.config, function_name) {
                     Ok(config) => {
-                            jobs.push_once(Job::CreateScratch, || {
+                        jobs.push_once(Job::CreateScratch, || start_create_scratch(ctx, config));
-                                start_create_scratch(ctx, config)
-                            });
                     }
                     Err(err) => {
                         log::error!("Failed to create scratch config: {err}");
                     }
                 }
             }
-            }
+            DiffViewAction::OpenSourcePath => {
-        }
+                let Ok(state) = state.read() else {
-
+                    return;
-        if self.queue_open_source_path {
+                };
-            self.queue_open_source_path = false;
-            if let Ok(state) = state.read() {
                 if let (Some(project_dir), Some(source_path)) = (
                     &state.config.project_dir,
                     state.config.selected_obj.as_ref().and_then(|obj| obj.source_path.as_ref()),
@@ -142,6 +289,67 @@ impl DiffViewState {
                     });
                 }
             }
+            DiffViewAction::SetDiffHighlight(column, kind) => {
+                self.function_state.set_highlight(column, kind);
+            }
+            DiffViewAction::ClearDiffHighlight => {
+                self.function_state.clear_highlight();
+            }
+            DiffViewAction::SelectingLeft(right_ref) => {
+                if self.post_build_nav.is_some() {
+                    // Ignore action if we're already navigating
+                    return;
+                }
+                let Ok(mut state) = state.write() else {
+                    return;
+                };
+                state.set_selecting_left(&right_ref.symbol_name);
+                self.post_build_nav = Some(DiffViewNavigation {
+                    view: Some(View::FunctionDiff),
+                    left_symbol: None,
+                    right_symbol: Some(right_ref),
+                });
+            }
+            DiffViewAction::SelectingRight(left_ref) => {
+                if self.post_build_nav.is_some() {
+                    // Ignore action if we're already navigating
+                    return;
+                }
+                let Ok(mut state) = state.write() else {
+                    return;
+                };
+                state.set_selecting_right(&left_ref.symbol_name);
+                self.post_build_nav = Some(DiffViewNavigation {
+                    view: Some(View::FunctionDiff),
+                    left_symbol: Some(left_ref),
+                    right_symbol: None,
+                });
+            }
+            DiffViewAction::SetMapping(view, left_ref, right_ref) => {
+                if self.post_build_nav.is_some() {
+                    // Ignore action if we're already navigating
+                    return;
+                }
+                let Ok(mut state) = state.write() else {
+                    return;
+                };
+                state.set_symbol_mapping(
+                    left_ref.symbol_name.clone(),
+                    right_ref.symbol_name.clone(),
+                );
+                if view == View::SymbolDiff {
+                    self.post_build_nav = Some(DiffViewNavigation::symbol_diff());
+                } else {
+                    self.post_build_nav = Some(DiffViewNavigation {
+                        view: Some(view),
+                        left_symbol: Some(left_ref),
+                        right_symbol: Some(right_ref),
+                    });
+                }
+            }
+            DiffViewAction::SetShowMappedSymbols(value) => {
+                self.symbol_state.show_mapped_symbols = value;
+            }
         }
     }
 }
@@ -158,11 +366,13 @@ pub fn match_color_for_symbol(match_percent: f32, appearance: &Appearance) -> Co
 
 fn symbol_context_menu_ui(
     ui: &mut Ui,
-    state: &mut SymbolViewState,
+    ctx: SymbolDiffContext<'_>,
-    arch: &dyn ObjArch,
+    other_ctx: Option<SymbolDiffContext<'_>>,
     symbol: &ObjSymbol,
+    symbol_diff: &ObjSymbolDiff,
     section: Option<&ObjSection>,
-) -> Option<View> {
+    column: usize,
+) -> Option<DiffViewNavigation> {
     let mut ret = None;
     ui.scope(|ui| {
         ui.style_mut().override_text_style = Some(egui::TextStyle::Monospace);
@@ -185,14 +395,35 @@ fn symbol_context_menu_ui(
             }
         }
         if let Some(section) = section {
-            let has_extab = arch.ppc().and_then(|ppc| ppc.extab_for_symbol(symbol)).is_some();
+            let has_extab =
+                ctx.obj.arch.ppc().and_then(|ppc| ppc.extab_for_symbol(symbol)).is_some();
             if has_extab && ui.button("Decode exception table").clicked() {
-                state.selected_symbol = Some(SymbolRefByName {
+                ret = Some(DiffViewNavigation::with_symbols(
-                    symbol_name: symbol.name.clone(),
+                    View::ExtabDiff,
-                    demangled_symbol_name: symbol.demangled_name.clone(),
+                    other_ctx,
-                    section_name: section.name.clone(),
+                    symbol,
+                    section,
+                    symbol_diff,
+                    column,
+                ));
+                ui.close_menu();
+            }
+
+            if ui.button("Map symbol").clicked() {
+                let symbol_ref = SymbolRefByName::new(symbol, Some(section));
+                if column == 0 {
+                    ret = Some(DiffViewNavigation {
+                        view: Some(View::FunctionDiff),
+                        left_symbol: Some(symbol_ref),
+                        right_symbol: None,
                     });
-                ret = Some(View::ExtabDiff);
+                } else {
+                    ret = Some(DiffViewNavigation {
+                        view: Some(View::FunctionDiff),
+                        left_symbol: None,
+                        right_symbol: Some(symbol_ref),
+                    });
+                }
                 ui.close_menu();
             }
         }
@@ -232,27 +463,28 @@ fn symbol_hover_ui(ui: &mut Ui, arch: &dyn ObjArch, symbol: &ObjSymbol, appearan
 }
 
 #[must_use]
-#[allow(clippy::too_many_arguments)]
+#[expect(clippy::too_many_arguments)]
 fn symbol_ui(
     ui: &mut Ui,
-    arch: &dyn ObjArch,
+    ctx: SymbolDiffContext<'_>,
+    other_ctx: Option<SymbolDiffContext<'_>>,
     symbol: &ObjSymbol,
     symbol_diff: &ObjSymbolDiff,
     section: Option<&ObjSection>,
-    state: &mut SymbolViewState,
+    state: &SymbolViewState,
     appearance: &Appearance,
-    left: bool,
+    column: usize,
-) -> Option<View> {
+) -> Option<DiffViewAction> {
-    if symbol.flags.0.contains(ObjSymbolFlags::Hidden) && !state.show_hidden_symbols {
-        return None;
-    }
     let mut ret = None;
+    if symbol.flags.0.contains(ObjSymbolFlags::Hidden) && !state.show_hidden_symbols {
+        return ret;
+    }
     let mut job = LayoutJob::default();
     let name: &str =
         if let Some(demangled) = &symbol.demangled_name { demangled } else { &symbol.name };
     let mut selected = false;
     if let Some(sym_ref) =
-        if left { state.highlighted_symbol.0 } else { state.highlighted_symbol.1 }
+        if column == 0 { state.highlighted_symbol.0 } else { state.highlighted_symbol.1 }
     {
         selected = symbol_diff.symbol_ref == sym_ref;
     }
@@ -284,7 +516,7 @@ fn symbol_ui(
     if let Some(match_percent) = symbol_diff.match_percent {
         write_text("(", appearance.text_color, &mut job, appearance.code_font.clone());
         write_text(
-            &format!("{match_percent:.0}%"),
+            &format!("{:.0}%", match_percent.floor()),
             match_color_for_symbol(match_percent, appearance),
             &mut job,
             appearance.code_font.clone(),
@@ -292,90 +524,166 @@ fn symbol_ui(
         write_text(") ", appearance.text_color, &mut job, appearance.code_font.clone());
     }
     write_text(name, appearance.highlight_color, &mut job, appearance.code_font.clone());
-    let response = SelectableLabel::new(selected, job)
+    let response = SelectableLabel::new(selected, job).ui(ui).on_hover_ui_at_pointer(|ui| {
-        .ui(ui)
+        symbol_hover_ui(ui, ctx.obj.arch.as_ref(), symbol, appearance)
-        .on_hover_ui_at_pointer(|ui| symbol_hover_ui(ui, arch, symbol, appearance));
+    });
     response.context_menu(|ui| {
-        ret = ret.or(symbol_context_menu_ui(ui, state, arch, symbol, section));
+        if let Some(result) =
+            symbol_context_menu_ui(ui, ctx, other_ctx, symbol, symbol_diff, section, column)
+        {
+            ret = Some(DiffViewAction::Navigate(result));
+        }
     });
     if response.clicked() {
         if let Some(section) = section {
-            if section.kind == ObjSectionKind::Code {
+            match section.kind {
-                state.selected_symbol = Some(SymbolRefByName {
+                ObjSectionKind::Code => {
-                    symbol_name: symbol.name.clone(),
+                    ret = Some(DiffViewAction::Navigate(DiffViewNavigation::with_symbols(
-                    demangled_symbol_name: symbol.demangled_name.clone(),
+                        View::FunctionDiff,
-                    section_name: section.name.clone(),
+                        other_ctx,
-                });
+                        symbol,
-                ret = Some(View::FunctionDiff);
+                        section,
-            } else if section.kind == ObjSectionKind::Data {
+                        symbol_diff,
-                state.selected_symbol = Some(SymbolRefByName {
+                        column,
-                    symbol_name: section.name.clone(),
+                    )));
-                    demangled_symbol_name: None,
+                }
-                    section_name: section.name.clone(),
+                ObjSectionKind::Data => {
-                });
+                    ret = Some(DiffViewAction::Navigate(DiffViewNavigation::with_symbols(
-                ret = Some(View::DataDiff);
+                        View::DataDiff,
+                        other_ctx,
+                        symbol,
+                        section,
+                        symbol_diff,
+                        column,
+                    )));
+                }
+                ObjSectionKind::Bss => {}
             }
         }
     } else if response.hovered() {
-        state.highlighted_symbol = if let Some(diff_symbol) = symbol_diff.diff_symbol {
+        ret = Some(if let Some(target_symbol) = symbol_diff.target_symbol {
-            if left {
+            if column == 0 {
-                (Some(symbol_diff.symbol_ref), Some(diff_symbol))
+                DiffViewAction::SetSymbolHighlight(
+                    Some(symbol_diff.symbol_ref),
+                    Some(target_symbol),
+                )
             } else {
-                (Some(diff_symbol), Some(symbol_diff.symbol_ref))
+                DiffViewAction::SetSymbolHighlight(
+                    Some(target_symbol),
+                    Some(symbol_diff.symbol_ref),
+                )
             }
         } else {
-            (None, None)
+            DiffViewAction::SetSymbolHighlight(None, None)
-        };
+        });
     }
     ret
 }
 
-fn symbol_matches_search(symbol: &ObjSymbol, search_regex: Option<&Regex>) -> bool {
+fn symbol_matches_filter(
-    if let Some(search_regex) = search_regex {
+    symbol: &ObjSymbol,
-        search_regex.is_match(&symbol.name)
+    diff: &ObjSymbolDiff,
-            || symbol.demangled_name.as_ref().map(|s| search_regex.is_match(s)).unwrap_or(false)
+    filter: SymbolFilter<'_>,
-    } else {
+) -> bool {
-        true
+    match filter {
+        SymbolFilter::None => true,
+        SymbolFilter::Search(regex) => {
+            regex.is_match(&symbol.name)
+                || symbol.demangled_name.as_ref().map(|s| regex.is_match(s)).unwrap_or(false)
+        }
+        SymbolFilter::Mapping(symbol_ref) => diff.target_symbol == Some(symbol_ref),
     }
 }
 
+#[derive(Copy, Clone)]
+pub enum SymbolFilter<'a> {
+    None,
+    Search(&'a Regex),
+    Mapping(SymbolRef),
+}
+
 #[must_use]
-fn symbol_list_ui(
+pub fn symbol_list_ui(
     ui: &mut Ui,
-    obj: &(ObjInfo, ObjDiff),
+    ctx: SymbolDiffContext<'_>,
-    state: &mut SymbolViewState,
+    other_ctx: Option<SymbolDiffContext<'_>>,
-    search_regex: Option<&Regex>,
+    state: &SymbolViewState,
+    filter: SymbolFilter<'_>,
     appearance: &Appearance,
-    left: bool,
+    column: usize,
-) -> Option<View> {
+) -> Option<DiffViewAction> {
     let mut ret = None;
-    let arch = obj.0.arch.as_ref();
     ScrollArea::both().auto_shrink([false, false]).show(ui, |ui| {
+        let mut mapping = BTreeMap::new();
+        if let SymbolFilter::Mapping(target_ref) = filter {
+            let mut show_mapped_symbols = state.show_mapped_symbols;
+            if ui.checkbox(&mut show_mapped_symbols, "Show mapped symbols").changed() {
+                ret = Some(DiffViewAction::SetShowMappedSymbols(show_mapped_symbols));
+            }
+            for mapping_diff in &ctx.diff.mapping_symbols {
+                if mapping_diff.target_symbol == Some(target_ref) {
+                    if !show_mapped_symbols {
+                        let symbol_diff = ctx.diff.symbol_diff(mapping_diff.symbol_ref);
+                        if symbol_diff.target_symbol.is_some() {
+                            continue;
+                        }
+                    }
+                    mapping.insert(mapping_diff.symbol_ref, mapping_diff);
+                }
+            }
+        } else {
+            for (symbol, diff) in ctx.obj.common.iter().zip(&ctx.diff.common) {
+                if !symbol_matches_filter(symbol, diff, filter) {
+                    continue;
+                }
+                mapping.insert(diff.symbol_ref, diff);
+            }
+            for (section, section_diff) in ctx.obj.sections.iter().zip(&ctx.diff.sections) {
+                for (symbol, symbol_diff) in section.symbols.iter().zip(&section_diff.symbols) {
+                    if !symbol_matches_filter(symbol, symbol_diff, filter) {
+                        continue;
+                    }
+                    mapping.insert(symbol_diff.symbol_ref, symbol_diff);
+                }
+            }
+        }
+
         ui.scope(|ui| {
             ui.style_mut().override_text_style = Some(egui::TextStyle::Monospace);
             ui.style_mut().wrap_mode = Some(egui::TextWrapMode::Extend);
 
-            if !obj.0.common.is_empty() {
+            // Skip sections with all symbols filtered out
+            if mapping.keys().any(|symbol_ref| symbol_ref.section_idx == SECTION_COMMON) {
                 CollapsingHeader::new(".comm").default_open(true).show(ui, |ui| {
-                    for (symbol, symbol_diff) in obj.0.common.iter().zip(&obj.1.common) {
+                    for (symbol_ref, symbol_diff) in mapping
-                        if !symbol_matches_search(symbol, search_regex) {
+                        .iter()
-                            continue;
+                        .filter(|(symbol_ref, _)| symbol_ref.section_idx == SECTION_COMMON)
-                        }
+                    {
-                        ret = ret.or(symbol_ui(
+                        let symbol = ctx.obj.section_symbol(*symbol_ref).1;
+                        if let Some(result) = symbol_ui(
                             ui,
-                            arch,
+                            ctx,
+                            other_ctx,
                             symbol,
                             symbol_diff,
                             None,
                             state,
                             appearance,
-                            left,
+                            column,
-                        ));
+                        ) {
+                            ret = Some(result);
+                        }
                     }
                 });
             }
 
-            for (section, section_diff) in obj.0.sections.iter().zip(&obj.1.sections) {
+            for ((section_index, section), section_diff) in
+                ctx.obj.sections.iter().enumerate().zip(&ctx.diff.sections)
+            {
+                // Skip sections with all symbols filtered out
+                if !mapping.keys().any(|symbol_ref| symbol_ref.section_idx == section_index) {
+                    continue;
+                }
                 let mut header = LayoutJob::simple_singleline(
                     format!("{} ({:x})", section.name, section.size),
                     appearance.code_font.clone(),
@@ -389,7 +697,7 @@ fn symbol_list_ui(
                         appearance.code_font.clone(),
                     );
                     write_text(
-                        &format!("{match_percent:.0}%"),
+                        &format!("{:.0}%", match_percent.floor()),
                         match_color_for_symbol(match_percent, appearance),
                         &mut header,
                         appearance.code_font.clone(),
@@ -406,40 +714,45 @@ fn symbol_list_ui(
                     .default_open(true)
                     .show(ui, |ui| {
                         if section.kind == ObjSectionKind::Code && state.reverse_fn_order {
-                            for (symbol, symbol_diff) in
+                            for (symbol, symbol_diff) in mapping
-                                section.symbols.iter().zip(&section_diff.symbols).rev()
+                                .iter()
+                                .filter(|(symbol_ref, _)| symbol_ref.section_idx == section_index)
+                                .rev()
                             {
-                                if !symbol_matches_search(symbol, search_regex) {
+                                let symbol = ctx.obj.section_symbol(*symbol).1;
-                                    continue;
+                                if let Some(result) = symbol_ui(
-                                }
-                                ret = ret.or(symbol_ui(
                                     ui,
-                                    arch,
+                                    ctx,
+                                    other_ctx,
                                     symbol,
                                     symbol_diff,
                                     Some(section),
                                     state,
                                     appearance,
-                                    left,
+                                    column,
-                                ));
+                                ) {
+                                    ret = Some(result);
+                                }
                             }
                         } else {
-                            for (symbol, symbol_diff) in
+                            for (symbol, symbol_diff) in mapping
-                                section.symbols.iter().zip(&section_diff.symbols)
+                                .iter()
+                                .filter(|(symbol_ref, _)| symbol_ref.section_idx == section_index)
                             {
-                                if !symbol_matches_search(symbol, search_regex) {
+                                let symbol = ctx.obj.section_symbol(*symbol).1;
-                                    continue;
+                                if let Some(result) = symbol_ui(
-                                }
-                                ret = ret.or(symbol_ui(
                                     ui,
-                                    arch,
+                                    ctx,
+                                    other_ctx,
                                     symbol,
                                     symbol_diff,
                                     Some(section),
                                     state,
                                     appearance,
-                                    left,
+                                    column,
-                                ));
+                                ) {
+                                    ret = Some(result);
+                                }
                             }
                         }
                     });
@@ -487,80 +800,62 @@ fn missing_obj_ui(ui: &mut Ui, appearance: &Appearance) {
     });
 }
 
-pub fn symbol_diff_ui(ui: &mut Ui, state: &mut DiffViewState, appearance: &Appearance) {
+#[derive(Copy, Clone)]
-    let DiffViewState { build, current_view, symbol_state, search, search_regex, .. } = state;
+pub struct SymbolDiffContext<'a> {
-    let Some(result) = build else {
+    pub obj: &'a ObjInfo,
-        return;
+    pub diff: &'a ObjDiff,
+}
+
+#[must_use]
+pub fn symbol_diff_ui(
+    ui: &mut Ui,
+    state: &mut DiffViewState,
+    appearance: &Appearance,
+) -> Option<DiffViewAction> {
+    let mut ret = None;
+    let Some(result) = &state.build else {
+        return ret;
     };
 
     // Header
     let available_width = ui.available_width();
-    let column_width = available_width / 2.0;
+    render_header(ui, available_width, 2, |ui, column| {
-    ui.allocate_ui_with_layout(
+        if column == 0 {
-        Vec2 { x: available_width, y: 100.0 },
-        Layout::left_to_right(Align::Min),
-        |ui| {
-            ui.style_mut().wrap_mode = Some(egui::TextWrapMode::Truncate);
-
             // Left column
-            ui.allocate_ui_with_layout(
-                Vec2 { x: column_width, y: 100.0 },
-                Layout::top_down(Align::Min),
-                |ui| {
-                    ui.set_width(column_width);
-
             ui.scope(|ui| {
                 ui.style_mut().override_text_style = Some(egui::TextStyle::Monospace);
 
-                        ui.label("Build target:");
+                ui.label("Target object");
                 if result.first_status.success {
                     if result.first_obj.is_none() {
                         ui.colored_label(appearance.replace_color, "Missing");
                     } else {
-                                ui.label("OK");
+                        ui.colored_label(appearance.highlight_color, state.object_name.clone());
                     }
                 } else {
                     ui.colored_label(appearance.delete_color, "Fail");
                 }
             });
 
-                    if TextEdit::singleline(search).hint_text("Filter symbols").ui(ui).changed() {
+            let mut search = state.search.clone();
-                        if search.is_empty() {
+            if TextEdit::singleline(&mut search).hint_text("Filter symbols").ui(ui).changed() {
-                            *search_regex = None;
+                ret = Some(DiffViewAction::SetSearch(search));
-                        } else if let Ok(regex) =
-                            RegexBuilder::new(search).case_insensitive(true).build()
-                        {
-                            *search_regex = Some(regex);
-                        } else {
-                            *search_regex = None;
             }
-                    }
+        } else if column == 1 {
-                },
-            );
-
             // Right column
-            ui.allocate_ui_with_layout(
-                Vec2 { x: column_width, y: 100.0 },
-                Layout::top_down(Align::Min),
-                |ui| {
-                    ui.set_width(column_width);
-
             ui.horizontal(|ui| {
                 ui.scope(|ui| {
                     ui.style_mut().override_text_style = Some(egui::TextStyle::Monospace);
-                            ui.label("Build base:");
+                    ui.label("Base object");
                 });
                 ui.separator();
                 if ui
-                            .add_enabled(
+                    .add_enabled(state.source_path_available, egui::Button::new("🖹 Source file"))
-                                state.source_path_available,
-                                egui::Button::new("🖹 Source file"),
-                            )
                     .on_hover_text_at_pointer("Open the source file in the default editor")
                     .on_disabled_hover_text("Source file metadata missing")
                     .clicked()
                 {
-                            state.queue_open_source_path = true;
+                    ret = Some(DiffViewAction::OpenSourcePath);
                 }
             });
 
@@ -570,7 +865,7 @@ pub fn symbol_diff_ui(ui: &mut Ui, state: &mut DiffViewState, appearance: &Appea
                     if result.second_obj.is_none() {
                         ui.colored_label(appearance.replace_color, "Missing");
                     } else {
-                                ui.label("OK");
+                        ui.colored_label(appearance.highlight_color, "OK");
                     }
                 } else {
                     ui.colored_label(appearance.delete_color, "Fail");
@@ -578,64 +873,66 @@ pub fn symbol_diff_ui(ui: &mut Ui, state: &mut DiffViewState, appearance: &Appea
             });
 
             if ui.add_enabled(!state.build_running, egui::Button::new("Build")).clicked() {
-                        state.queue_build = true;
+                ret = Some(DiffViewAction::Build);
             }
-                },
+        }
-            );
+    });
-        },
-    );
-    ui.separator();
 
     // Table
-    let mut ret = None;
+    let filter = match &state.search_regex {
-    StripBuilder::new(ui).size(Size::remainder()).vertical(|mut strip| {
+        Some(regex) => SymbolFilter::Search(regex),
-        strip.strip(|builder| {
+        _ => SymbolFilter::None,
-            builder.sizes(Size::remainder(), 2).horizontal(|mut strip| {
+    };
-                strip.cell(|ui| {
+    render_strips(ui, available_width, 2, |ui, column| {
-                    ui.push_id("left", |ui| {
+        if column == 0 {
+            // Left column
             if result.first_status.success {
-                            if let Some(obj) = &result.first_obj {
+                if let Some((obj, diff)) = &result.first_obj {
-                                ret = ret.or(symbol_list_ui(
+                    if let Some(result) = symbol_list_ui(
                         ui,
-                                    obj,
+                        SymbolDiffContext { obj, diff },
-                                    symbol_state,
+                        result
-                                    search_regex.as_ref(),
+                            .second_obj
+                            .as_ref()
+                            .map(|(obj, diff)| SymbolDiffContext { obj, diff }),
+                        &state.symbol_state,
+                        filter,
                         appearance,
-                                    true,
+                        column,
-                                ));
+                    ) {
+                        ret = Some(result);
+                    }
                 } else {
                     missing_obj_ui(ui, appearance);
                 }
             } else {
                 build_log_ui(ui, &result.first_status, appearance);
             }
-                    });
+        } else if column == 1 {
-                });
+            // Right column
-                strip.cell(|ui| {
-                    ui.push_id("right", |ui| {
             if result.second_status.success {
-                            if let Some(obj) = &result.second_obj {
+                if let Some((obj, diff)) = &result.second_obj {
-                                ret = ret.or(symbol_list_ui(
+                    if let Some(result) = symbol_list_ui(
                         ui,
-                                    obj,
+                        SymbolDiffContext { obj, diff },
-                                    symbol_state,
+                        result
-                                    search_regex.as_ref(),
+                            .first_obj
+                            .as_ref()
+                            .map(|(obj, diff)| SymbolDiffContext { obj, diff }),
+                        &state.symbol_state,
+                        filter,
                         appearance,
-                                    false,
+                        column,
-                                ));
+                    ) {
+                        ret = Some(result);
+                    }
                 } else {
                     missing_obj_ui(ui, appearance);
                 }
             } else {
                 build_log_ui(ui, &result.second_status, appearance);
             }
-                    });
-                });
-            });
-        });
-    });
-
-    if let Some(view) = ret {
-        *current_view = view;
         }
+    });
+    ret
 }