Working `rel make` & more

- Added `elf info`
- Improved `rel info`
- Colored output for `shasum`
- Fix section `rename` in RELs
- Added padding symbols to avoid linker issues
- Automatically set symbols to "active" in .comment output

Cargo.lock

@@ -100,6 +100,23 @@ dependencies = [
  "syn 1.0.107",
 ]
 
+[[package]]
+name = "array-init"
+version = "2.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3d62b7694a562cdf5a74227903507c56ab2cc8bdd1f781ed5cb4cf9c9f810bfc"
+
+[[package]]
+name = "atty"
+version = "0.2.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d9b39be18770d11421cdb1b9947a45dd3f37e93092cbf377614828a319d5fee8"
+dependencies = [
+ "hermit-abi 0.1.19",
+ "libc",
+ "winapi",
+]
+
 [[package]]
 name = "autocfg"
 version = "1.1.0"
@@ -142,6 +159,30 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "binrw"
+version = "0.11.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ab81d22cbd2d745852348b2138f3db2103afa8ce043117a374581926a523e267"
+dependencies = [
+ "array-init",
+ "binrw_derive",
+ "bytemuck",
+]
+
+[[package]]
+name = "binrw_derive"
+version = "0.11.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d6b019a3efebe7f453612083202887b6f1ace59e20d010672e336eea4ed5be97"
+dependencies = [
+ "either",
+ "owo-colors",
+ "proc-macro2",
+ "quote",
+ "syn 1.0.107",
+]
+
 [[package]]
 name = "bitflags"
 version = "1.3.2"
@@ -157,6 +198,12 @@ dependencies = [
  "generic-array",
 ]
 
+[[package]]
+name = "bytemuck"
+version = "1.13.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "17febce684fd15d89027105661fec94afb475cb995fbc59d2865198446ba2eea"
+
 [[package]]
 name = "byteorder"
 version = "1.4.3"
@@ -260,13 +307,14 @@ dependencies = [
 
 [[package]]
 name = "decomp-toolkit"
-version = "0.3.7"
+version = "0.4.0"
 dependencies = [
  "anyhow",
  "ar",
  "argp",
  "base16ct",
  "base64",
+ "binrw",
  "byteorder",
  "cwdemangle",
  "dol",
@@ -285,12 +333,14 @@ dependencies = [
  "num_enum",
  "object 0.31.1",
  "once_cell",
+ "owo-colors",
  "path-slash",
  "petgraph",
  "ppc750cl",
  "rayon",
  "regex",
  "rmp-serde",
+ "rustc-hash",
  "serde",
  "serde_json",
  "serde_repr",
@@ -423,6 +473,15 @@ version = "0.14.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2c6201b9ff9fd90a5a3bac2e56a830d0caa509576f0e503818ee82c181b3437a"
 
+[[package]]
+name = "hermit-abi"
+version = "0.1.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "62b467343b94ba476dcb2500d242dadbb39557df889310ac77c5d99100aaac33"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "hermit-abi"
 version = "0.3.2"
@@ -455,6 +514,12 @@ dependencies = [
  "hashbrown 0.14.0",
 ]
 
+[[package]]
+name = "is_ci"
+version = "1.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "616cde7c720bb2bb5824a224687d8f77bfd38922027f01d825cd7453be5099fb"
+
 [[package]]
 name = "itertools"
 version = "0.11.0"
@@ -488,6 +553,15 @@ version = "0.4.19"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b06a4cde4c0f271a446782e3eff8de789548ce57dbc8eca9292c27f4a42004b4"
 
+[[package]]
+name = "matchers"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8263075bb86c5a1b1427b5ae862e8889656f126e9f77c484496e8b47cf5c5558"
+dependencies = [
+ "regex-automata 0.1.10",
+]
+
 [[package]]
 name = "memchr"
 version = "2.5.0"
@@ -564,7 +638,7 @@ version = "1.16.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4161fcb6d602d4d2081af7c3a45852d875a03dd337a6bfdd6e06407b61342a43"
 dependencies = [
- "hermit-abi",
+ "hermit-abi 0.3.2",
  "libc",
 ]
 
@@ -622,6 +696,15 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b15813163c1d831bf4a13c3610c05c0d03b39feb07f7e09fa234dac9b15aaf39"
 
+[[package]]
+name = "owo-colors"
+version = "3.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c1b04fb49957986fdce4d6ee7a65027d55d4b6d2265e5848bbb507b58ccfdb6f"
+dependencies = [
+ "supports-color",
+]
+
 [[package]]
 name = "paste"
 version = "1.0.11"
@@ -739,8 +822,17 @@ checksum = "89089e897c013b3deb627116ae56a6955a72b8bed395c9526af31c9fe528b484"
 dependencies = [
  "aho-corasick",
  "memchr",
- "regex-automata",
+ "regex-automata 0.3.0",
- "regex-syntax",
+ "regex-syntax 0.7.3",
+]
+
+[[package]]
+name = "regex-automata"
+version = "0.1.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6c230d73fb8d8c1b9c0b3135c5142a8acee3a0558fb8db5cf1cb65f8d7862132"
+dependencies = [
+ "regex-syntax 0.6.29",
 ]
 
 [[package]]
@@ -751,9 +843,15 @@ checksum = "fa250384981ea14565685dea16a9ccc4d1c541a13f82b9c168572264d1df8c56"
 dependencies = [
  "aho-corasick",
  "memchr",
- "regex-syntax",
+ "regex-syntax 0.7.3",
 ]
 
+[[package]]
+name = "regex-syntax"
+version = "0.6.29"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f162c6dd7b008981e4d40210aca20b4bd0f9b60ca9271061b07f78537722f2e1"
+
 [[package]]
 name = "regex-syntax"
 version = "0.7.3"
@@ -788,6 +886,12 @@ version = "0.1.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d626bb9dae77e28219937af045c257c28bfd3f69333c512553507f5f9798cb76"
 
+[[package]]
+name = "rustc-hash"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "08d43f7aa6b08d49f382cde6a7982047c3426db949b1424bc4b7ec9ae12c6ce2"
+
 [[package]]
 name = "ryu"
 version = "1.0.12"
@@ -881,6 +985,16 @@ version = "1.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "62bb4feee49fdd9f707ef802e22365a35de4b7b299de4763d44bfea899442ff9"
 
+[[package]]
+name = "supports-color"
+version = "1.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8ba6faf2ca7ee42fdd458f4347ae0a9bd6bcc445ad7cb57ad82b383f18870d6f"
+dependencies = [
+ "atty",
+ "is_ci",
+]
+
 [[package]]
 name = "syn"
 version = "1.0.107"
@@ -992,10 +1106,14 @@ version = "0.3.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "30a651bc37f915e81f087d86e62a18eec5f79550c7faff886f7090b4ea757c77"
 dependencies = [
+ "matchers",
  "nu-ansi-term",
+ "once_cell",
+ "regex",
  "sharded-slab",
  "smallvec",
  "thread_local",
+ "tracing",
  "tracing-core",
  "tracing-log",
 ]

Cargo.toml

@@ -3,7 +3,7 @@ name = "decomp-toolkit"
 description = "Yet another GameCube/Wii decompilation toolkit."
 authors = ["Luke Street <luke@street.dev>"]
 license = "MIT OR Apache-2.0"
-version = "0.3.7"
+version = "0.4.0"
 edition = "2021"
 publish = false
 build = "build.rs"
@@ -26,6 +26,7 @@ ar = { git = "https://github.com/bjorn3/rust-ar.git", branch = "write_symbol_tab
 argp = "0.3.0"
 base16ct = "0.2.0"
 base64 = "0.21.2"
+binrw = "0.11.2"
 byteorder = "1.4.3"
 cwdemangle = "0.1.5"
 dol = { git = "https://github.com/encounter/ppc750cl", rev = "5f6e991bf495388c4104f188d2e90c79da9f78de" }
@@ -44,11 +45,13 @@ multimap = "0.9.0"
 num_enum = "0.6.1"
 object = { version = "0.31.1", features = ["read_core", "std", "elf", "write_std"], default-features = false }
 once_cell = "1.18.0"
+owo-colors = { version = "3.5.0", features = ["supports-colors"] }
 path-slash = "0.2.1"
 petgraph = "0.6.3"
 ppc750cl = { git = "https://github.com/encounter/ppc750cl", rev = "5f6e991bf495388c4104f188d2e90c79da9f78de" }
 rayon = "1.7.0"
 regex = "1.9.0"
+rustc-hash = "1.1.0"
 serde = "1.0.166"
 serde_json = "1.0.104"
 serde_repr = "0.1.14"
@@ -57,7 +60,7 @@ sha-1 = "0.10.1"
 smallvec = "1.11.0"
 tracing = "0.1.37"
 tracing-attributes = "0.1.26"
-tracing-subscriber = "0.3.17"
+tracing-subscriber = { version = "0.3.17", features = ["env-filter"] }
 
 [build-dependencies]
 anyhow = { version = "1.0.71", features = ["backtrace"] }

README.md

@@ -105,8 +105,8 @@ it operates as a one-shot assembly generator, it still suffers from many of the
 ### ppcdis
 
 [ppcdis](https://github.com/SeekyCt/ppcdis) is one of the tools that inspired decomp-toolkit. It has more accurate
-analysis than doldisasm.py, and has similar goals to decomp-toolkit. It also has some features that decomp-toolkit does
+analysis than doldisasm.py, and has similar goals to decomp-toolkit. It's been used successfully in several
-not yet, like support for REL files.
+decompilation projects.
 
 However, decomp-toolkit has a few advantages:
 
@@ -226,7 +226,7 @@ Generates `ldscript.lcf` for `mwldeppc.exe`.
 
 **Future work**
 
-- Support REL and RSO files
+- Support RSO files
 - Add more signatures
 - Rework CodeWarrior map parsing
 
@@ -335,7 +335,7 @@ $ dtk map symbol Game.MAP 'Function__5ClassFv'
 
 ### rel info
 
-Prints basic information about a REL file.
+Prints information about a REL file.
 
 ```shell
 $ dtk rel info input.rel
@@ -355,7 +355,7 @@ $ dtk rel info main.dol rels/*.rel -o merged.elf
 > [!WARNING]  
 > This command is not yet functional.
 
-Prints basic information about an RSO file.
+Prints information about an RSO file.
 
 ```shell
 $ dtk rso info input.rso

src/analysis/cfa.rs

@@ -166,13 +166,8 @@ impl AnalyzerState {
     pub fn detect_functions(&mut self, obj: &ObjInfo) -> Result<()> {
         // Apply known functions from extab
         for (&addr, &size) in &obj.known_functions {
-            let (section_index, _) = obj
+            self.function_entries.insert(addr);
-                .sections
+            self.function_bounds.insert(addr, Some(addr + size));
-                .at_address(addr)
-                .context(format!("Function {:#010X} outside of any section", addr))?;
-            let addr_ref = SectionAddress::new(section_index, addr);
-            self.function_entries.insert(addr_ref);
-            self.function_bounds.insert(addr_ref, Some(addr_ref + size));
         }
         // Apply known functions from symbols
         for (_, symbol) in obj.symbols.by_kind(ObjSymbolKind::Function) {

src/analysis/pass.rs

@@ -201,7 +201,11 @@ impl AnalysisPass for FindRelCtorsDtors {
             return Ok(());
         }
 
-        log::debug!("Found .ctors and .dtors: {:?}", possible_sections);
+        log::debug!(
+            "Found .ctors and .dtors: {}, {}",
+            possible_sections[0].0,
+            possible_sections[1].0
+        );
         let ctors_section_index = possible_sections[0].0;
         state.known_sections.insert(ctors_section_index, ".ctors".to_string());
         state.known_symbols.insert(SectionAddress::new(ctors_section_index, 0), ObjSymbol {
@@ -311,7 +315,11 @@ impl AnalysisPass for FindRelRodataData {
             return Ok(());
         }
 
-        log::debug!("Found .rodata and .data: {:?}", possible_sections);
+        log::debug!(
+            "Found .rodata and .data: {}, {}",
+            possible_sections[0].0,
+            possible_sections[1].0
+        );
         let rodata_section_index = possible_sections[0].0;
         state.known_sections.insert(rodata_section_index, ".rodata".to_string());
 

src/analysis/signatures.rs

@@ -264,6 +264,8 @@ fn apply_ctors_signatures(obj: &mut ObjInfo) -> Result<()> {
             align: None,
             common: false,
             autogenerated: true,
+            skip: false,
+            rename: None,
         })?;
     }
     Ok(())
@@ -362,6 +364,8 @@ fn apply_dtors_signatures(obj: &mut ObjInfo) -> Result<()> {
                 align: None,
                 common: false,
                 autogenerated: true,
+                skip: false,
+                rename: None,
             })?;
         }
     }
@@ -439,6 +443,5 @@ pub fn apply_signatures_post(obj: &mut ObjInfo) -> Result<()> {
             apply_signature(obj, symbol_addr, &signature)?;
         }
     }
-    log::debug!("Done!");
     Ok(())
 }

src/analysis/slices.rs

@@ -74,7 +74,7 @@ fn check_sequence(
 
 impl FunctionSlices {
     pub fn end(&self) -> Option<SectionAddress> {
-        self.blocks.last_key_value().map(|(_, &end)| end).flatten()
+        self.blocks.last_key_value().and_then(|(_, &end)| end)
     }
 
     pub fn start(&self) -> Option<SectionAddress> {
@@ -404,7 +404,7 @@ impl FunctionSlices {
                 // Likely __noreturn
             }
             (None, Some(e)) => {
-                log::info!("{:#010X?}", self);
+                log::warn!("{:#010X?}", self);
                 bail!("Unpaired epilogue {:#010X}", e);
             }
         }

src/analysis/tracker.rs

@@ -403,8 +403,9 @@ impl Tracker {
         from: SectionAddress,
         addr: u32,
     ) -> Option<SectionAddress> {
-        if let Some((&start, &end)) = obj.blocked_ranges.range(..=from.address).next_back() {
+        if let Some((&start, &end)) = obj.blocked_ranges.range(..=from).next_back() {
-            if from.address >= start && from.address < end {
+            if from.section == start.section && from.address >= start.address && from.address < end
+            {
                 return None;
             }
         }

src/cmd/dol.rs

@@ -12,7 +12,6 @@ use std::{
 use anyhow::{anyhow, bail, Context, Result};
 use argp::FromArgs;
 use itertools::Itertools;
-use memmap2::Mmap;
 use rayon::prelude::*;
 use serde::{Deserialize, Serialize};
 use tracing::{debug, info, info_span};
@@ -28,7 +27,6 @@ use crate::{
         signatures::{apply_signatures, apply_signatures_post},
         tracker::Tracker,
     },
-    cmd::shasum::file_sha1,
     obj::{
         best_match_for_reloc, ObjDataKind, ObjInfo, ObjReloc, ObjRelocKind, ObjSectionKind,
         ObjSymbol, ObjSymbolFlagSet, ObjSymbolFlags, ObjSymbolKind, ObjSymbolScope, SymbolIndex,
@@ -43,13 +41,13 @@ use crate::{
         dep::DepFile,
         dol::process_dol,
         elf::{process_elf, write_elf},
-        file::{buf_writer, map_file, map_reader, touch, Reader},
+        file::{buf_writer, decompress_if_needed, map_file, touch, verify_hash, Reader},
         lcf::{asm_path_for_unit, generate_ldscript, obj_path_for_unit},
         map::apply_map_file,
         rel::process_rel,
         rso::{process_rso, DOL_SECTION_ABS, DOL_SECTION_NAMES},
         split::{is_linker_generated_object, split_obj, update_splits},
-        yaz0,
+        IntoCow, ToCow,
     },
 };
 
@@ -225,7 +223,7 @@ impl ModuleConfig {
     pub fn file_prefix(&self) -> Cow<'_, str> {
         match self.file_name() {
             Cow::Borrowed(s) => {
-                Cow::Borrowed(s.split_once('.').map(|(prefix, _)| prefix).unwrap_or(&s))
+                Cow::Borrowed(s.split_once('.').map(|(prefix, _)| prefix).unwrap_or(s))
             }
             Cow::Owned(s) => {
                 Cow::Owned(s.split_once('.').map(|(prefix, _)| prefix).unwrap_or(&s).to_string())
@@ -379,40 +377,32 @@ fn info(args: InfoArgs) -> Result<()> {
         );
     }
     println!("\nDiscovered symbols:");
-    println!("\t{: >23} | {: <10} | {: <10}", "Name", "Address", "Size");
+    println!("\t{: >10} | {: <10} | {: <10} | {: <10}", "Section", "Address", "Size", "Name");
     for (_, symbol) in obj.symbols.iter_ordered().chain(obj.symbols.iter_abs()) {
-        if symbol.name.starts_with('@') || is_auto_symbol(&symbol.name) {
+        if symbol.name.starts_with('@') || is_auto_symbol(symbol) {
             continue;
         }
-        if symbol.size_known {
+        let section_str = if let Some(section) = symbol.section {
-            println!("\t{: >23} | {:#010X} | {: <#10X}", symbol.name, symbol.address, symbol.size);
+            obj.sections[section].name.as_str()
         } else {
-            let size_str = if symbol.section.is_none() { "ABS" } else { "?" };
+            "ABS"
-            println!("\t{: >23} | {:#010X} | {: <10}", symbol.name, symbol.address, size_str);
+        };
-        }
+        let size_str = if symbol.size_known {
+            format!("{:#X}", symbol.size).into_cow()
+        } else if symbol.section.is_none() {
+            "ABS".to_cow()
+        } else {
+            "?".to_cow()
+        };
+        println!(
+            "\t{: >10} | {: <#10X} | {: <10} | {: <10}",
+            section_str, symbol.address, size_str, symbol.name
+        );
     }
     println!("\n{} discovered functions from exception table", obj.known_functions.len());
     Ok(())
 }
 
-fn verify_hash<P: AsRef<Path>>(path: P, hash_str: &str) -> Result<()> {
-    let mut hash_bytes = [0u8; 20];
-    hex::decode_to_slice(hash_str, &mut hash_bytes)
-        .with_context(|| format!("Invalid SHA-1 '{hash_str}'"))?;
-    let file = File::open(path.as_ref())
-        .with_context(|| format!("Failed to open file '{}'", path.as_ref().display()))?;
-    let found_hash = file_sha1(file)?;
-    if found_hash.as_ref() == hash_bytes {
-        Ok(())
-    } else {
-        Err(anyhow!(
-            "Hash mismatch: expected {}, but was {}",
-            hex::encode(hash_bytes),
-            hex::encode(found_hash)
-        ))
-    }
-}
-
 type ModuleMap<'a> = BTreeMap<u32, (&'a ModuleConfig, ObjInfo)>;
 
 fn update_symbols(obj: &mut ObjInfo, modules: &ModuleMap<'_>) -> Result<()> {
@@ -632,15 +622,9 @@ fn resolve_external_relocations(
     Ok(())
 }
 
-fn decompress_if_needed(map: &Mmap) -> Result<Cow<[u8]>> {
+type AnalyzeResult = (ObjInfo, Vec<PathBuf>);
-    Ok(if map.len() > 4 && map[0..4] == *b"Yaz0" {
-        Cow::Owned(yaz0::decompress_file(&mut map_reader(map))?)
-    } else {
-        Cow::Borrowed(map)
-    })
-}
 
-fn load_analyze_dol(config: &ProjectConfig) -> Result<(ObjInfo, Vec<PathBuf>)> {
+fn load_analyze_dol(config: &ProjectConfig) -> Result<AnalyzeResult> {
     // log::info!("Loading {}", config.object.display());
     if let Some(hash_str) = &config.base.hash {
         verify_hash(&config.base.object, hash_str)?;
@@ -697,7 +681,7 @@ fn split_write_obj(
     obj: &mut ObjInfo,
     config: &ProjectConfig,
     module_config: &ModuleConfig,
-    out_dir: &PathBuf,
+    out_dir: &Path,
     no_update: bool,
 ) -> Result<OutputModule> {
     debug!("Performing relocation analysis");
@@ -723,15 +707,15 @@ fn split_write_obj(
     if !no_update {
         debug!("Writing configuration");
         if let Some(symbols_path) = &module_config.symbols {
-            write_symbols_file(symbols_path, &obj)?;
+            write_symbols_file(symbols_path, obj)?;
         }
         if let Some(splits_path) = &module_config.splits {
-            write_splits_file(splits_path, &obj, false)?;
+            write_splits_file(splits_path, obj, false)?;
         }
     }
 
     debug!("Splitting {} objects", obj.link_order.len());
-    let split_objs = split_obj(&obj)?;
+    let split_objs = split_obj(obj)?;
 
     debug!("Writing object files");
     let obj_dir = out_dir.join("obj");
@@ -757,7 +741,7 @@ fn split_write_obj(
     }
 
     // Generate ldscript.lcf
-    fs::write(&out_config.ldscript, generate_ldscript(&obj, config.auto_force_files)?)?;
+    fs::write(&out_config.ldscript, generate_ldscript(obj, config.auto_force_files)?)?;
 
     debug!("Writing disassembly");
     let asm_dir = out_dir.join("asm");
@@ -772,17 +756,18 @@ fn split_write_obj(
     Ok(out_config)
 }
 
-fn load_analyze_rel(
+fn load_analyze_rel(config: &ProjectConfig, module_config: &ModuleConfig) -> Result<AnalyzeResult> {
-    config: &ProjectConfig,
-    module_config: &ModuleConfig,
-) -> Result<(ObjInfo, Vec<PathBuf>)> {
     debug!("Loading {}", module_config.object.display());
     if let Some(hash_str) = &module_config.hash {
         verify_hash(&module_config.object, hash_str)?;
     }
     let map = map_file(&module_config.object)?;
     let buf = decompress_if_needed(&map)?;
-    let mut module_obj = process_rel(Reader::new(&buf))?;
+    let (_, mut module_obj) = process_rel(&mut Reader::new(buf.as_ref()))?;
+
+    if let Some(comment_version) = config.mw_comment_version {
+        module_obj.mw_comment = Some(MWComment::new(comment_version)?);
+    }
 
     let mut dep = vec![module_config.object.clone()];
     if let Some(map_path) = &module_config.map {
@@ -833,8 +818,8 @@ fn split(args: SplitArgs) -> Result<()> {
         module_count,
         rayon::current_num_threads()
     );
-    let mut dol_result: Option<Result<(ObjInfo, Vec<PathBuf>)>> = None;
+    let mut dol_result: Option<Result<AnalyzeResult>> = None;
-    let mut modules_result: Option<Result<Vec<(ObjInfo, Vec<PathBuf>)>>> = None;
+    let mut modules_result: Option<Result<Vec<AnalyzeResult>>> = None;
     let start = Instant::now();
     rayon::scope(|s| {
         // DOL
@@ -999,7 +984,7 @@ fn split(args: SplitArgs) -> Result<()> {
     // }
 
     let duration = command_start.elapsed();
-    info!("Total duration: {}.{:03}s", duration.as_secs(), duration.subsec_millis());
+    info!("Total time: {}.{:03}s", duration.as_secs(), duration.subsec_millis());
     Ok(())
 }
 
@@ -1167,7 +1152,11 @@ fn diff(args: DiffArgs) -> Result<()> {
     log::info!("Loading {}", args.map_file.display());
     apply_map_file(&args.map_file, &mut linked_obj)?;
 
-    for orig_sym in obj.symbols.iter().filter(|s| s.kind != ObjSymbolKind::Section) {
+    for orig_sym in obj
+        .symbols
+        .iter()
+        .filter(|s| !matches!(s.kind, ObjSymbolKind::Unknown | ObjSymbolKind::Section))
+    {
         let Some(orig_section_index) = orig_sym.section else { continue };
         let orig_section = &obj.sections[orig_section_index];
         let (linked_section_index, linked_section) =
@@ -1244,7 +1233,9 @@ fn diff(args: DiffArgs) -> Result<()> {
     }
 
     // Data diff
-    for orig_sym in obj.symbols.iter().filter(|s| s.kind != ObjSymbolKind::Section) {
+    for orig_sym in obj.symbols.iter().filter(|s| {
+        s.size > 0 && !matches!(s.kind, ObjSymbolKind::Unknown | ObjSymbolKind::Section)
+    }) {
         let Some(orig_section_index) = orig_sym.section else { continue };
         let orig_section = &obj.sections[orig_section_index];
         let (linked_section_index, linked_section) =

src/cmd/elf.rs

@@ -19,11 +19,13 @@ use crate::{
     obj::ObjKind,
     util::{
         asm::write_asm,
+        comment::{read_comment_sym, MWComment},
         config::{write_splits_file, write_symbols_file},
         elf::{process_elf, write_elf},
-        file::{buf_writer, process_rsp},
+        file::{buf_writer, process_rsp, Reader},
         signatures::{compare_signature, generate_signature, FunctionSignature},
         split::split_obj,
+        IntoCow, ToCow,
     },
 };
 
@@ -43,6 +45,7 @@ enum SubCommand {
     Fixup(FixupArgs),
     Signatures(SignaturesArgs),
     Split(SplitArgs),
+    Info(InfoArgs),
 }
 
 #[derive(FromArgs, PartialEq, Eq, Debug)]
@@ -108,6 +111,15 @@ pub struct SignaturesArgs {
     out_file: PathBuf,
 }
 
+#[derive(FromArgs, PartialEq, Eq, Debug)]
+/// Prints information about an ELF file.
+#[argp(subcommand, name = "info")]
+pub struct InfoArgs {
+    #[argp(positional)]
+    /// input file
+    input: PathBuf,
+}
+
 pub fn run(args: Args) -> Result<()> {
     match args.command {
         SubCommand::Config(c_args) => config(c_args),
@@ -115,6 +127,7 @@ pub fn run(args: Args) -> Result<()> {
         SubCommand::Fixup(c_args) => fixup(c_args),
         SubCommand::Split(c_args) => split(c_args),
         SubCommand::Signatures(c_args) => signatures(c_args),
+        SubCommand::Info(c_args) => info(c_args),
     }
 }
 
@@ -467,3 +480,120 @@ fn signatures(args: SignaturesArgs) -> Result<()> {
     out.flush()?;
     Ok(())
 }
+
+fn info(args: InfoArgs) -> Result<()> {
+    let in_buf = fs::read(&args.input)
+        .with_context(|| format!("Failed to open input file: '{}'", args.input.display()))?;
+    let in_file = object::read::File::parse(&*in_buf).context("Failed to parse input ELF")?;
+
+    println!("ELF type: {:?}", in_file.kind());
+    println!("Section count: {}", in_file.sections().count());
+    println!("Symbol count: {}", in_file.symbols().count());
+    println!(
+        "Relocation count: {}",
+        in_file.sections().map(|s| s.relocations().count()).sum::<usize>()
+    );
+
+    println!("\nSections:");
+    println!(
+        "{: >15} | {: <10} | {: <10} | {: <10} | {: <10}",
+        "Name", "Type", "Size", "File Off", "Index"
+    );
+    for section in in_file.sections().skip(1) {
+        let kind_str = match section.kind() {
+            SectionKind::Text => "code".to_cow(),
+            SectionKind::Data => "data".to_cow(),
+            SectionKind::ReadOnlyData => "rodata".to_cow(),
+            SectionKind::UninitializedData => "bss".to_cow(),
+            SectionKind::Metadata => continue, // "metadata".to_cow()
+            SectionKind::Other => "other".to_cow(),
+            _ => format!("unknown: {:?}", section.kind()).into_cow(),
+        };
+        println!(
+            "{: >15} | {: <10} | {: <#10X} | {: <#10X} | {: <10}",
+            section.name()?,
+            kind_str,
+            section.size(),
+            section.file_range().unwrap_or_default().0,
+            section.index().0
+        );
+    }
+
+    println!("\nSymbols:");
+    println!("{: >15} | {: <10} | {: <10} | {: <10}", "Section", "Address", "Size", "Name");
+    for symbol in in_file.symbols().filter(|s| s.is_definition()) {
+        let section_str = if let Some(section) = symbol.section_index() {
+            in_file.section_by_index(section)?.name()?.to_string().into_cow()
+        } else {
+            "ABS".to_cow()
+        };
+        let size_str = if symbol.section_index().is_none() {
+            "ABS".to_cow()
+        } else {
+            format!("{:#X}", symbol.size()).into_cow()
+        };
+        println!(
+            "{: >15} | {: <#10X} | {: <10} | {: <10}",
+            section_str,
+            symbol.address(),
+            size_str,
+            symbol.name()?
+        );
+    }
+
+    if let Some(comment_section) = in_file.section_by_name(".comment") {
+        let data = comment_section.uncompressed_data()?;
+        if !data.is_empty() {
+            let mut reader = Reader::new(&*data);
+            let header =
+                MWComment::parse_header(&mut reader).context("While reading .comment section")?;
+            println!("\nMetrowerks metadata (.comment):");
+            println!("\tVersion: {}", header.version);
+            println!(
+                "\tCompiler version: {}.{}.{}.{}",
+                header.compiler_version[0],
+                header.compiler_version[1],
+                header.compiler_version[2],
+                header.compiler_version[3]
+            );
+            println!("\tPool data: {}", header.pool_data);
+            println!("\tFloat: {:?}", header.float);
+            println!(
+                "\tProcessor: {}",
+                if header.processor == 0x16 {
+                    "Gekko".to_cow()
+                } else {
+                    format!("{:#X}", header.processor).into_cow()
+                }
+            );
+            println!(
+                "\tIncompatible return small structs: {}",
+                header.incompatible_return_small_structs
+            );
+            println!(
+                "\tIncompatible sfpe double params: {}",
+                header.incompatible_sfpe_double_params
+            );
+            println!("\tUnsafe global reg vars: {}", header.unsafe_global_reg_vars);
+            println!("\n{: >10} | {: <6} | {: <6} | {: <10}", "Align", "Vis", "Active", "Symbol");
+            for symbol in in_file.symbols() {
+                let comment_sym = read_comment_sym(&mut reader)?;
+                if symbol.is_definition() {
+                    println!(
+                        "{: >10} | {: <#6X} | {: <#6X} | {: <10}",
+                        comment_sym.align,
+                        comment_sym.vis_flags,
+                        comment_sym.active_flags,
+                        symbol.name()?
+                    );
+                }
+            }
+            ensure!(
+                data.len() - reader.position() as usize == 0,
+                ".comment section data not fully read"
+            );
+        }
+    }
+
+    Ok(())
+}

src/cmd/rel.rs

@@ -1,27 +1,45 @@
 use std::{
     collections::{btree_map, BTreeMap},
+    ffi::OsStr,
     fs,
+    io::Write,
     path::PathBuf,
+    time::Instant,
 };
 
-use anyhow::{bail, ensure, Context, Result};
+use anyhow::{anyhow, bail, ensure, Context, Result};
 use argp::FromArgs;
+use object::{
+    Architecture, Endianness, Object, ObjectSection, ObjectSymbol, RelocationTarget, SymbolIndex,
+};
+use rayon::prelude::*;
+use rustc_hash::FxHashMap;
+use tracing::{info, info_span};
 
 use crate::{
     analysis::{
         cfa::{AnalyzerState, SectionAddress},
-        pass::{AnalysisPass, FindSaveRestSleds, FindTRKInterruptVectorTable},
+        pass::{
+            AnalysisPass, FindRelCtorsDtors, FindRelRodataData, FindSaveRestSleds,
+            FindTRKInterruptVectorTable,
+        },
         signatures::{apply_signatures, apply_signatures_post},
         tracker::Tracker,
     },
     array_ref_mut,
-    obj::{ObjInfo, ObjReloc, ObjRelocKind, ObjSection, ObjSymbol},
+    cmd::dol::ProjectConfig,
+    obj::{ObjInfo, ObjReloc, ObjRelocKind, ObjSection, ObjSectionKind, ObjSymbol},
     util::{
+        config::is_auto_symbol,
         dol::process_dol,
-        elf::write_elf,
+        elf::{to_obj_reloc_kind, write_elf},
-        file::{map_file, map_reader, FileIterator},
+        file::{
+            buf_reader, buf_writer, decompress_if_needed, map_file, process_rsp, verify_hash,
+            FileIterator, Reader,
+        },
         nested::NestedMap,
-        rel::process_rel,
+        rel::{process_rel, process_rel_header, write_rel, RelHeader, RelReloc, RelWriteInfo},
+        IntoCow, ToCow,
     },
 };
 
@@ -37,6 +55,7 @@ pub struct Args {
 #[argp(subcommand)]
 enum SubCommand {
     Info(InfoArgs),
+    Make(MakeArgs),
     Merge(MergeArgs),
 }
 
@@ -64,17 +83,227 @@ pub struct MergeArgs {
     out_file: PathBuf,
 }
 
+#[derive(FromArgs, PartialEq, Eq, Debug)]
+/// Creates RELs from an ELF + PLF(s).
+#[argp(subcommand, name = "make")]
+pub struct MakeArgs {
+    #[argp(positional)]
+    /// input file(s)
+    files: Vec<PathBuf>,
+    #[argp(option, short = 'c')]
+    /// (optional) project configuration file
+    config: Option<PathBuf>,
+}
+
 pub fn run(args: Args) -> Result<()> {
     match args.command {
         SubCommand::Info(c_args) => info(c_args),
         SubCommand::Merge(c_args) => merge(c_args),
+        SubCommand::Make(c_args) => make(c_args),
     }
 }
 
+fn load_obj(buf: &[u8]) -> Result<object::File> {
+    let obj = object::read::File::parse(buf)?;
+    match obj.architecture() {
+        Architecture::PowerPc => {}
+        arch => bail!("Unexpected architecture: {arch:?}"),
+    };
+    ensure!(obj.endianness() == Endianness::Big, "Expected big endian");
+    Ok(obj)
+}
+
+fn make(args: MakeArgs) -> Result<()> {
+    let total = Instant::now();
+
+    // Load existing REL headers (if specified)
+    let mut existing_headers = BTreeMap::<u32, RelHeader>::new();
+    if let Some(config_path) = &args.config {
+        let config: ProjectConfig = serde_yaml::from_reader(&mut buf_reader(config_path)?)?;
+        for module_config in &config.modules {
+            if let Some(hash_str) = &module_config.hash {
+                verify_hash(&module_config.object, hash_str)?;
+            }
+            let map = map_file(&module_config.object)?;
+            let buf = decompress_if_needed(&map)?;
+            let header = process_rel_header(&mut Reader::new(buf.as_ref()))?;
+            existing_headers.insert(header.module_id, header);
+        }
+    }
+
+    let files = process_rsp(&args.files)?;
+    info!("Loading {} modules", files.len());
+
+    // Load all modules
+    let handles = files.iter().map(map_file).collect::<Result<Vec<_>>>()?;
+    let modules = handles
+        .par_iter()
+        .zip(&files)
+        .map(|(map, path)| {
+            load_obj(map).with_context(|| format!("Failed to load '{}'", path.display()))
+        })
+        .collect::<Result<Vec<_>>>()?;
+
+    // Create symbol map
+    let start = Instant::now();
+    let mut symbol_map = FxHashMap::<&[u8], (usize, SymbolIndex)>::default();
+    for (module_id, module) in modules.iter().enumerate() {
+        for symbol in module.symbols() {
+            if symbol.is_definition() && symbol.scope() == object::SymbolScope::Dynamic {
+                symbol_map.entry(symbol.name_bytes()?).or_insert((module_id, symbol.index()));
+            }
+        }
+    }
+
+    // Resolve relocations
+    let mut resolved = 0usize;
+    let mut relocations = Vec::<Vec<RelReloc>>::with_capacity(modules.len() - 1);
+    relocations.resize_with(modules.len() - 1, Vec::new);
+    for ((module_id, module), relocations) in
+        modules.iter().enumerate().skip(1).zip(&mut relocations)
+    {
+        for section in module.sections() {
+            for (address, reloc) in section.relocations() {
+                let reloc_target = match reloc.target() {
+                    RelocationTarget::Symbol(idx) => {
+                        module.symbol_by_index(idx).with_context(|| {
+                            format!("Relocation against invalid symbol index {}", idx.0)
+                        })?
+                    }
+                    reloc_target => bail!("Unsupported relocation target: {reloc_target:?}"),
+                };
+                let (target_module_id, target_symbol) = if reloc_target.is_undefined() {
+                    resolved += 1;
+                    symbol_map
+                        .get(reloc_target.name_bytes()?)
+                        .map(|&(module_id, symbol_idx)| {
+                            (module_id, modules[module_id].symbol_by_index(symbol_idx).unwrap())
+                        })
+                        .ok_or_else(|| {
+                            anyhow!(
+                                "Failed to find symbol {} in any module",
+                                reloc_target.name().unwrap_or("[invalid]")
+                            )
+                        })?
+                } else {
+                    (module_id, reloc_target)
+                };
+                relocations.push(RelReloc {
+                    kind: to_obj_reloc_kind(reloc.kind())?,
+                    section: section.index().0 as u8,
+                    address: address as u32,
+                    module_id: target_module_id as u32,
+                    target_section: target_symbol.section_index().unwrap().0 as u8,
+                    addend: target_symbol.address() as u32,
+                });
+            }
+        }
+    }
+
+    let duration = start.elapsed();
+    info!(
+        "Symbol resolution completed in {}.{:03}s (resolved {} symbols)",
+        duration.as_secs(),
+        duration.subsec_millis(),
+        resolved
+    );
+
+    // Write RELs
+    let start = Instant::now();
+    for (((module_id, module), path), relocations) in
+        modules.iter().enumerate().zip(&files).skip(1).zip(relocations)
+    {
+        let name =
+            path.file_stem().unwrap_or(OsStr::new("[unknown]")).to_str().unwrap_or("[invalid]");
+        let _span = info_span!("module", name = %name).entered();
+        let mut info = RelWriteInfo {
+            module_id: module_id as u32,
+            version: 3,
+            name_offset: None,
+            name_size: None,
+            align: None,
+            bss_align: None,
+            section_count: None,
+        };
+        if let Some(existing_module) = existing_headers.get(&(module_id as u32)) {
+            info.version = existing_module.version;
+            info.name_offset = Some(existing_module.name_offset);
+            info.name_size = Some(existing_module.name_size);
+            info.align = existing_module.align;
+            info.bss_align = existing_module.bss_align;
+            info.section_count = Some(existing_module.num_sections as usize);
+        }
+        let rel_path = path.with_extension("rel");
+        let mut w = buf_writer(&rel_path)?;
+        write_rel(&mut w, &info, module, relocations)
+            .with_context(|| format!("Failed to write '{}'", rel_path.display()))?;
+        w.flush()?;
+    }
+    let duration = start.elapsed();
+    info!("RELs written in {}.{:03}s", duration.as_secs(), duration.subsec_millis());
+
+    let duration = total.elapsed();
+    info!("Total time: {}.{:03}s", duration.as_secs(), duration.subsec_millis());
+    Ok(())
+}
+
 fn info(args: InfoArgs) -> Result<()> {
     let map = map_file(args.rel_file)?;
-    let rel = process_rel(map_reader(&map))?;
+    let buf = decompress_if_needed(&map)?;
-    println!("Read REL module ID {}", rel.module_id);
+    let (header, mut module_obj) = process_rel(&mut Reader::new(buf.as_ref()))?;
+
+    let mut state = AnalyzerState::default();
+    state.detect_functions(&module_obj)?;
+    FindRelCtorsDtors::execute(&mut state, &module_obj)?;
+    FindRelRodataData::execute(&mut state, &module_obj)?;
+    state.apply(&mut module_obj)?;
+
+    apply_signatures(&mut module_obj)?;
+    apply_signatures_post(&mut module_obj)?;
+
+    println!("REL module ID: {}", header.module_id);
+    println!("REL version: {}", header.version);
+    println!("Original section count: {}", header.num_sections);
+    println!("\nSections:");
+    println!(
+        "{: >10} | {: <10} | {: <10} | {: <10} | {: <10}",
+        "Name", "Type", "Size", "File Off", "Index"
+    );
+    for (_, section) in module_obj.sections.iter() {
+        let kind_str = match section.kind {
+            ObjSectionKind::Code => "code",
+            ObjSectionKind::Data => "data",
+            ObjSectionKind::ReadOnlyData => "rodata",
+            ObjSectionKind::Bss => "bss",
+        };
+        println!(
+            "{: >10} | {: <10} | {: <#10X} | {: <#10X} | {: <10}",
+            section.name, kind_str, section.size, section.file_offset, section.elf_index
+        );
+    }
+    println!("\nDiscovered symbols:");
+    println!("{: >10} | {: <10} | {: <10} | {: <10}", "Section", "Address", "Size", "Name");
+    for (_, symbol) in module_obj.symbols.iter_ordered() {
+        if symbol.name.starts_with('@') || is_auto_symbol(symbol) {
+            continue;
+        }
+        let section_str = if let Some(section) = symbol.section {
+            module_obj.sections[section].name.as_str()
+        } else {
+            "ABS"
+        };
+        let size_str = if symbol.size_known {
+            format!("{:#X}", symbol.size).into_cow()
+        } else if symbol.section.is_none() {
+            "ABS".to_cow()
+        } else {
+            "?".to_cow()
+        };
+        println!(
+            "{: >10} | {: <#10X} | {: <10} | {: <10}",
+            section_str, symbol.address, size_str, symbol.name
+        );
+    }
     Ok(())
 }
 
@@ -94,7 +323,7 @@ fn merge(args: MergeArgs) -> Result<()> {
     for result in FileIterator::new(&args.rel_files)? {
         let (path, entry) = result?;
         log::info!("Loading {}", path.display());
-        let obj = process_rel(entry.as_reader())?;
+        let (_, obj) = process_rel(&mut entry.as_reader())?;
         match module_map.entry(obj.module_id) {
             btree_map::Entry::Vacant(e) => e.insert(obj),
             btree_map::Entry::Occupied(_) => bail!("Duplicate module ID {}", obj.module_id),

src/cmd/shasum.rs

@@ -6,6 +6,7 @@ use std::{
 
 use anyhow::{anyhow, bail, Context, Result};
 use argp::FromArgs;
+use owo_colors::OwoColorize;
 use sha1::{Digest, Sha1};
 
 use crate::util::file::{process_rsp, touch};
@@ -66,14 +67,17 @@ fn check(file: File) -> Result<()> {
             File::open(file_name).with_context(|| format!("Failed to open file '{file_name}'"))?;
         let found_hash = file_sha1(file)?;
         if hash_bytes == found_hash.as_ref() {
-            println!("{file_name}: OK");
+            println!("{}: {}", file_name, "OK".green());
         } else {
-            println!("{file_name}: FAILED");
+            println!("{}: {}", file_name, "FAILED".red());
             mismatches += 1;
         }
     }
     if mismatches != 0 {
-        eprintln!("WARNING: {mismatches} computed checksum did NOT match");
+        eprintln!(
+            "{}",
+            format!("WARNING: {mismatches} computed checksum(s) did NOT match").yellow()
+        );
         std::process::exit(1);
     }
     Ok(())

src/main.rs

@@ -1,6 +1,8 @@
 use std::{ffi::OsStr, path::PathBuf, str::FromStr};
 
 use argp::{FromArgValue, FromArgs};
+use tracing::level_filters::LevelFilter;
+use tracing_subscriber::EnvFilter;
 
 pub mod analysis;
 pub mod argp_version;
@@ -60,10 +62,10 @@ struct TopLevel {
     #[argp(option, short = 'C')]
     /// Change working directory.
     chdir: Option<PathBuf>,
-    #[argp(option, short = 'L', default = "LogLevel::Info")]
+    #[argp(option, short = 'L')]
     /// Minimum logging level. (Default: info)
     /// Possible values: error, warn, info, debug, trace
-    log_level: LogLevel,
+    log_level: Option<LogLevel>,
     /// Print version information and exit.
     #[argp(switch, short = 'V')]
     version: bool,
@@ -86,11 +88,29 @@ enum SubCommand {
 }
 
 fn main() {
-    let format = tracing_subscriber::fmt::format().with_target(false).without_time();
-    tracing_subscriber::fmt().event_format(format).init();
-    // TODO reimplement log level selection
-
     let args: TopLevel = argp_version::from_env();
+    let format = tracing_subscriber::fmt::format().with_target(false).without_time();
+    let builder = tracing_subscriber::fmt().event_format(format);
+    if let Some(level) = args.log_level {
+        builder
+            .with_max_level(match level {
+                LogLevel::Error => LevelFilter::ERROR,
+                LogLevel::Warn => LevelFilter::WARN,
+                LogLevel::Info => LevelFilter::INFO,
+                LogLevel::Debug => LevelFilter::DEBUG,
+                LogLevel::Trace => LevelFilter::TRACE,
+            })
+            .init();
+    } else {
+        builder
+            .with_env_filter(
+                EnvFilter::builder()
+                    .with_default_directive(LevelFilter::INFO.into())
+                    .from_env_lossy(),
+            )
+            .init();
+    }
+
     let mut result = Ok(());
     if let Some(dir) = &args.chdir {
         result = std::env::set_current_dir(dir).map_err(|e| {

src/obj/mod.rs

@@ -18,7 +18,10 @@ pub use symbols::{
     ObjSymbolScope, ObjSymbols, SymbolIndex,
 };
 
-use crate::util::{comment::MWComment, rel::RelReloc};
+use crate::{
+    analysis::cfa::SectionAddress,
+    util::{comment::MWComment, rel::RelReloc},
+};
 
 #[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
 pub enum ObjKind {
@@ -63,12 +66,11 @@ pub struct ObjInfo {
     pub arena_hi: Option<u32>,
 
     // Extracted
-    pub named_sections: BTreeMap<u32, String>,
     pub link_order: Vec<ObjUnit>,
-    pub blocked_ranges: BTreeMap<u32, u32>, // start -> end
+    pub blocked_ranges: BTreeMap<SectionAddress, u32>, // start -> end
 
     // From extab
-    pub known_functions: BTreeMap<u32, u32>,
+    pub known_functions: BTreeMap<SectionAddress, u32>,
 
     // REL
     /// Module ID (0 for main)
@@ -99,8 +101,6 @@ impl ObjInfo {
             db_stack_addr: None,
             arena_lo: None,
             arena_hi: None,
-            // splits: Default::default(),
-            named_sections: Default::default(),
             link_order: vec![],
             blocked_ranges: Default::default(),
             known_functions: Default::default(),
@@ -276,6 +276,8 @@ impl ObjInfo {
                 align: new_align,
                 common: split.common,
                 autogenerated: new_autogenerated,
+                skip: false,  // ?
+                rename: None, // ?
             })?;
             return Ok(());
         }

src/obj/splits.rs

@@ -15,6 +15,10 @@ pub struct ObjSplit {
     pub common: bool,
     /// Generated, replaceable by user.
     pub autogenerated: bool,
+    /// Skip when emitting the split object.
+    pub skip: bool,
+    /// Override the section name in the split object. (e.g. `.ctors$10`)
+    pub rename: Option<String>,
 }
 
 /// Splits within a section.

src/obj/symbols.rs

@@ -37,6 +37,8 @@ flags! {
         ForceActive,
         /// Symbol isn't referenced by any relocations
         RelocationIgnore,
+        /// Symbol won't be written to symbols file
+        NoWrite,
     }
 }
 
@@ -78,6 +80,9 @@ impl ObjSymbolFlagSet {
     #[inline]
     pub fn is_relocation_ignore(&self) -> bool { self.0.contains(ObjSymbolFlags::RelocationIgnore) }
 
+    #[inline]
+    pub fn is_no_write(&self) -> bool { self.0.contains(ObjSymbolFlags::NoWrite) }
+
     #[inline]
     pub fn set_scope(&mut self, scope: ObjSymbolScope) {
         match scope {
@@ -196,7 +201,7 @@ impl ObjSymbols {
             self.at_section_address(section_index, in_symbol.address as u32).find(|(_, symbol)| {
                 symbol.kind == in_symbol.kind ||
                     // Replace auto symbols with real symbols
-                    (symbol.kind == ObjSymbolKind::Unknown && is_auto_symbol(&symbol.name))
+                    (symbol.kind == ObjSymbolKind::Unknown && is_auto_symbol(symbol))
             })
         } else if self.obj_kind == ObjKind::Executable {
             // TODO hmmm
@@ -205,6 +210,7 @@ impl ObjSymbols {
             bail!("ABS symbol in relocatable object: {:?}", in_symbol);
         };
         let target_symbol_idx = if let Some((symbol_idx, existing)) = opt {
+            let replace = replace || (is_auto_symbol(existing) && !is_auto_symbol(&in_symbol));
             let size =
                 if existing.size_known && in_symbol.size_known && existing.size != in_symbol.size {
                     // TODO fix and promote back to warning

src/util/asm.rs

@@ -4,7 +4,7 @@ use std::{
     io::Write,
 };
 
-use anyhow::{anyhow, bail, ensure, Result};
+use anyhow::{anyhow, bail, ensure, Context, Result};
 use itertools::Itertools;
 use ppc750cl::{disasm_iter, Argument, Ins, Opcode};
 
@@ -438,7 +438,8 @@ fn write_data<W: Write>(
                     write_symbol_entry(w, symbols, entry)?;
                 }
                 current_symbol_kind = find_symbol_kind(current_symbol_kind, symbols, vec)?;
-                current_data_kind = find_data_kind(current_data_kind, symbols, vec)?;
+                current_data_kind = find_data_kind(current_data_kind, symbols, vec)
+                    .with_context(|| format!("At address {:#010X}", sym_addr))?;
                 entry = entry_iter.next();
             } else if current_address > sym_addr {
                 let dbg_symbols = vec.iter().map(|e| &symbols[e.index]).collect_vec();
@@ -550,10 +551,16 @@ fn find_data_kind(
             SymbolEntryKind::Start => {
                 let new_kind = symbols[entry.index].data_kind;
                 if !matches!(new_kind, ObjDataKind::Unknown) {
-                    ensure!(
+                    if found && new_kind != kind {
-                        !found || new_kind == kind,
+                        for entry in entries {
-                        "Conflicting data kinds found: {kind:?} and {new_kind:?}"
+                            log::error!("Symbol {:?}", symbols[entry.index]);
+                        }
+                        bail!(
+                            "Conflicting data kinds found: {kind:?} and {new_kind:?}",
+                            kind = kind,
+                            new_kind = new_kind
                         );
+                    }
                     found = true;
                     kind = new_kind;
                 }

src/util/comment.rs

@@ -169,7 +169,7 @@ pub struct CommentSym {
 }
 
 impl CommentSym {
-    pub fn from(symbol: &ObjSymbol) -> Self {
+    pub fn from(symbol: &ObjSymbol, force_active: bool) -> Self {
         let align = match symbol.align {
             Some(align) => align,
             None => {
@@ -196,8 +196,12 @@ impl CommentSym {
             vis_flags |= 0xD;
         }
         let mut active_flags = 0;
-        if symbol.flags.is_force_active() {
+        if symbol.flags.is_force_active()
-            active_flags |= 0x8; // TODO what is 0x10?
+            || (force_active
+                && matches!(symbol.kind, ObjSymbolKind::Function | ObjSymbolKind::Object)
+                && symbol.flags.is_global())
+        {
+            active_flags |= 0x8;
         }
         Self { align, vis_flags, active_flags }
     }

src/util/config.rs

@@ -11,6 +11,7 @@ use once_cell::sync::Lazy;
 use regex::{Captures, Regex};
 
 use crate::{
+    analysis::cfa::SectionAddress,
     obj::{
         ObjDataKind, ObjInfo, ObjKind, ObjSectionKind, ObjSplit, ObjSymbol, ObjSymbolFlagSet,
         ObjSymbolFlags, ObjSymbolKind, ObjUnit,
@@ -118,7 +119,13 @@ pub fn parse_symbol_line(line: &str, obj: &mut ObjInfo) -> Result<Option<ObjSymb
                             "Symbol {} requires size != 0 with noreloc",
                             symbol.name
                         );
-                        obj.blocked_ranges.insert(addr, addr + symbol.size as u32);
+                        ensure!(
+                            section.is_some(),
+                            "Symbol {} requires section with noreloc",
+                            symbol.name
+                        );
+                        let addr = SectionAddress::new(section.unwrap(), symbol.address as u32);
+                        obj.blocked_ranges.insert(addr, addr.address + symbol.size as u32);
                     }
                     _ => bail!("Unknown symbol attribute '{attr}'"),
                 }
@@ -133,7 +140,9 @@ pub fn parse_symbol_line(line: &str, obj: &mut ObjInfo) -> Result<Option<ObjSymb
 }
 
 pub fn is_skip_symbol(symbol: &ObjSymbol) -> bool {
-    let _ = symbol;
+    if symbol.flags.is_no_write() {
+        return true;
+    }
     // symbol.name.starts_with("lbl_")
     //     || symbol.name.starts_with("func_")
     //     || symbol.name.starts_with("switch_")
@@ -142,7 +151,9 @@ pub fn is_skip_symbol(symbol: &ObjSymbol) -> bool {
     false
 }
 
-pub fn is_auto_symbol(name: &str) -> bool { name.starts_with("lbl_") || name.starts_with("fn_") }
+pub fn is_auto_symbol(symbol: &ObjSymbol) -> bool {
+    symbol.name.starts_with("lbl_") || symbol.name.starts_with("fn_")
+}
 
 #[inline]
 pub fn write_symbols_file<P: AsRef<Path>>(path: P, obj: &ObjInfo) -> Result<()> {
@@ -188,9 +199,11 @@ fn write_symbol<W: Write>(w: &mut W, obj: &ObjInfo, symbol: &ObjSymbol) -> Resul
     // if symbol.flags.is_force_active() {
     //     write!(w, " force_active")?;
     // }
-    if obj.blocked_ranges.contains_key(&(symbol.address as u32)) {
+    if let Some(section) = symbol.section {
+        if obj.blocked_ranges.contains_key(&SectionAddress::new(section, symbol.address as u32)) {
             write!(w, " noreloc")?;
         }
+    }
     writeln!(w)?;
     Ok(())
 }
@@ -335,10 +348,11 @@ pub fn write_splits<W: Write>(w: &mut W, obj: &ObjInfo, all: bool) -> Result<()>
             if split.common {
                 write!(w, " common")?;
             }
-            if let Some(name) = obj.named_sections.get(&addr) {
+            if let Some(name) = &split.rename {
-                if name != &section.name {
                 write!(w, " rename:{}", name)?;
             }
+            if split.skip {
+                write!(w, " skip")?;
             }
             writeln!(w)?;
         }
@@ -354,6 +368,7 @@ struct SplitSection {
     /// Whether this is a part of common BSS.
     common: bool,
     rename: Option<String>,
+    skip: bool,
 }
 
 struct SplitUnit {
@@ -443,6 +458,8 @@ fn parse_section_line(captures: Captures, state: &SplitState) -> Result<SplitLin
         return Ok(SplitLine::Section(section));
     }
 
+    let mut start = None;
+    let mut end = None;
     let mut section = SplitSection {
         name: captures["name"].to_string(),
         start: 0,
@@ -450,13 +467,14 @@ fn parse_section_line(captures: Captures, state: &SplitState) -> Result<SplitLin
         align: None,
         common: false,
         rename: None,
+        skip: false,
     };
 
     for attr in captures["attrs"].split(' ').filter(|&s| !s.is_empty()) {
         if let Some((attr, value)) = attr.split_once(':') {
             match attr {
-                "start" => section.start = parse_hex(value)?,
+                "start" => start = Some(parse_hex(value)?),
-                "end" => section.end = parse_hex(value)?,
+                "end" => end = Some(parse_hex(value)?),
                 "align" => section.align = Some(u32::from_str(value)?),
                 "rename" => section.rename = Some(value.to_string()),
                 _ => bail!("Unknown split attribute '{attr}'"),
@@ -469,11 +487,14 @@ fn parse_section_line(captures: Captures, state: &SplitState) -> Result<SplitLin
                         section.align = Some(4);
                     }
                 }
+                "skip" => section.skip = true,
                 _ => bail!("Unknown split attribute '{attr}'"),
             }
         }
     }
-    if section.start > 0 && section.end > 0 {
+    if let (Some(start), Some(end)) = (start, end) {
+        section.start = start;
+        section.end = end;
         Ok(SplitLine::UnitSection(section))
     } else {
         Err(anyhow!("Section '{}' missing start or end address", section.name))
@@ -531,7 +552,7 @@ pub fn apply_splits<R: BufRead>(r: R, obj: &mut ObjInfo) -> Result<()> {
                         obj.sections.count()
                     );
                 };
-                if let Err(_) = obj_section.rename(name.clone()) {
+                if obj_section.rename(name.clone()).is_err() {
                     // Manual section
                     obj_section.kind =
                         kind.ok_or_else(|| anyhow!("Section '{}' missing type", name))?;
@@ -545,7 +566,15 @@ pub fn apply_splits<R: BufRead>(r: R, obj: &mut ObjInfo) -> Result<()> {
             }
             (
                 SplitState::Unit(unit),
-                SplitLine::UnitSection(SplitSection { name, start, end, align, common, rename }),
+                SplitLine::UnitSection(SplitSection {
+                    name,
+                    start,
+                    end,
+                    align,
+                    common,
+                    rename,
+                    skip,
+                }),
             ) => {
                 let (section_index, _) = match obj.sections.by_name(&name)? {
                     Some(v) => Ok(v),
@@ -573,10 +602,9 @@ pub fn apply_splits<R: BufRead>(r: R, obj: &mut ObjInfo) -> Result<()> {
                     align,
                     common,
                     autogenerated: false,
+                    skip,
+                    rename,
                 });
-                if let Some(name) = rename {
-                    obj.named_sections.insert(start, name);
-                }
             }
             _ => {}
         }

src/util/dol.rs

@@ -4,7 +4,7 @@ use anyhow::{anyhow, bail, ensure, Result};
 use dol::{Dol, DolSection, DolSectionType};
 
 use crate::{
-    analysis::cfa::locate_sda_bases,
+    analysis::cfa::{locate_sda_bases, SectionAddress},
     obj::{
         ObjArchitecture, ObjInfo, ObjKind, ObjSection, ObjSectionKind, ObjSymbol, ObjSymbolFlagSet,
         ObjSymbolFlags, ObjSymbolKind,
@@ -406,8 +406,15 @@ pub fn process_dol<P: AsRef<Path>>(path: P) -> Result<ObjInfo> {
 
         for entry in &eti_entries {
             // Add functions from extabindex entries as known function bounds
-            if let Some(old_value) = obj.known_functions.insert(entry.function, entry.function_size)
+            let (section_index, _) = obj.sections.at_address(entry.function).map_err(|_| {
-            {
+                anyhow!(
+                    "Failed to locate section for function {:#010X} (referenced from extabindex entry {:#010X})",
+                    entry.function,
+                    entry.address,
+                )
+            })?;
+            let addr = SectionAddress::new(section_index, entry.function);
+            if let Some(old_value) = obj.known_functions.insert(addr, entry.function_size) {
                 if old_value != entry.function_size {
                     log::warn!(
                         "Conflicting sizes for {:#010X}: {:#X} != {:#X}",

src/util/elf.rs

@@ -304,6 +304,8 @@ pub fn process_elf<P: AsRef<Path>>(path: P) -> Result<ObjInfo> {
                     align: None,
                     common: false, // TODO
                     autogenerated: false,
+                    skip: false,
+                    rename: None,
                 });
             }
         }
@@ -483,13 +485,19 @@ pub fn write_elf(obj: &ObjInfo) -> Result<Vec<u8>> {
         }
     }
 
-    // Add symbols
+    // Add symbols, starting with local symbols
-    for (symbol, symbol_map) in obj.symbols.iter().zip(&mut symbol_map) {
+    for (symbol_index, symbol) in obj
+        .symbols
+        .iter()
+        .enumerate()
+        .filter(|&(_, s)| s.flags.is_local())
+        .chain(obj.symbols.iter().enumerate().filter(|&(_, s)| !s.flags.is_local()))
+    {
         if obj.kind == ObjKind::Relocatable && symbol.kind == ObjSymbolKind::Section {
             // We wrote section symbols above, so skip them here
             let section_index =
                 symbol.section.ok_or_else(|| anyhow!("section symbol without section index"))?;
-            *symbol_map = Some(section_symbol_offset + section_index as u32);
+            symbol_map[symbol_index] = Some(section_symbol_offset + section_index as u32);
             continue;
         }
 
@@ -536,9 +544,9 @@ pub fn write_elf(obj: &ObjInfo) -> Result<Vec<u8>> {
             num_local = writer.symbol_count();
         }
         out_symbols.push(OutSymbol { index, sym });
-        *symbol_map = Some(index.0);
+        symbol_map[symbol_index] = Some(index.0);
         if let Some(comment_data) = &mut comment_data {
-            write_comment_sym(comment_data, CommentSym::from(symbol))?;
+            write_comment_sym(comment_data, CommentSym::from(symbol, true))?;
         }
     }
 
@@ -807,14 +815,8 @@ fn to_obj_symbol(
     })
 }
 
-fn to_obj_reloc(
+pub fn to_obj_reloc_kind(kind: RelocationKind) -> Result<ObjRelocKind> {
-    obj_file: &object::File<'_>,
+    Ok(match kind {
-    symbol_indexes: &[Option<usize>],
-    section_data: &[u8],
-    address: u64,
-    reloc: Relocation,
-) -> Result<Option<ObjReloc>> {
-    let reloc_kind = match reloc.kind() {
         RelocationKind::Absolute => ObjRelocKind::Absolute,
         RelocationKind::Elf(kind) => match kind {
             elf::R_PPC_ADDR16_LO => ObjRelocKind::PpcAddr16Lo,
@@ -823,10 +825,20 @@ fn to_obj_reloc(
             elf::R_PPC_REL24 => ObjRelocKind::PpcRel24,
             elf::R_PPC_REL14 => ObjRelocKind::PpcRel14,
             elf::R_PPC_EMB_SDA21 => ObjRelocKind::PpcEmbSda21,
-            _ => bail!("Unhandled PPC relocation type: {kind}"),
+            _ => bail!("Unhandled ELF relocation type: {kind}"),
         },
-        _ => bail!("Unhandled relocation type: {:?}", reloc.kind()),
+        _ => bail!("Unhandled relocation type: {:?}", kind),
-    };
+    })
+}
+
+fn to_obj_reloc(
+    obj_file: &object::File<'_>,
+    symbol_indexes: &[Option<usize>],
+    section_data: &[u8],
+    address: u64,
+    reloc: Relocation,
+) -> Result<Option<ObjReloc>> {
+    let reloc_kind = to_obj_reloc_kind(reloc.kind())?;
     let symbol = match reloc.target() {
         RelocationTarget::Symbol(idx) => {
             obj_file.symbol_by_index(idx).context("Failed to locate relocation target symbol")?

src/util/file.rs

@@ -1,4 +1,5 @@
 use std::{
+    borrow::Cow,
     fs::{DirBuilder, File, OpenOptions},
     io::{BufRead, BufReader, BufWriter, Cursor, Read},
     path::{Path, PathBuf},
@@ -10,7 +11,10 @@ use filetime::{set_file_mtime, FileTime};
 use memmap2::{Mmap, MmapOptions};
 use path_slash::PathBufExt;
 
-use crate::util::{rarc, rarc::Node, yaz0};
+use crate::{
+    cmd::shasum::file_sha1,
+    util::{rarc, rarc::Node, yaz0, IntoCow, ToCow},
+};
 
 /// Opens a memory mapped file.
 pub fn map_file<P: AsRef<Path>>(path: P) -> Result<Mmap> {
@@ -25,7 +29,7 @@ pub type Reader<'a> = Cursor<&'a [u8]>;
 
 /// Creates a reader for the memory mapped file.
 #[inline]
-pub fn map_reader(mmap: &Mmap) -> Reader { Cursor::new(&**mmap) }
+pub fn map_reader(mmap: &Mmap) -> Reader { Reader::new(&**mmap) }
 
 /// Creates a buffered reader around a file (not memory mapped).
 pub fn buf_reader<P: AsRef<Path>>(path: P) -> Result<BufReader<File>> {
@@ -130,14 +134,6 @@ impl RarcIterator {
         }
         paths
     }
-
-    fn decompress_if_needed(buf: &[u8]) -> Result<Vec<u8>> {
-        if buf.len() > 4 && buf[0..4] == *b"Yaz0" {
-            yaz0::decompress_file(&mut Cursor::new(buf))
-        } else {
-            Ok(buf.to_vec())
-        }
-    }
 }
 
 impl Iterator for RarcIterator {
@@ -152,8 +148,8 @@ impl Iterator for RarcIterator {
         self.index += 1;
 
         let slice = &self.file[off as usize..off as usize + size as usize];
-        match Self::decompress_if_needed(slice) {
+        match decompress_if_needed(slice) {
-            Ok(buf) => Some(Ok((path, buf))),
+            Ok(buf) => Some(Ok((path, buf.into_owned()))),
             Err(e) => Some(Err(e)),
         }
     }
@@ -170,7 +166,7 @@ impl FileEntry {
     pub fn as_reader(&self) -> Reader {
         match self {
             Self::Map(map) => map_reader(map),
-            Self::Buffer(slice) => Cursor::new(slice),
+            Self::Buffer(slice) => Reader::new(slice),
         }
     }
 }
@@ -257,3 +253,29 @@ pub fn touch<P: AsRef<Path>>(path: P) -> std::io::Result<()> {
         }
     }
 }
+
+pub fn decompress_if_needed(buf: &[u8]) -> Result<Cow<[u8]>> {
+    Ok(if buf.len() > 4 && buf[0..4] == *b"Yaz0" {
+        yaz0::decompress_file(&mut Reader::new(buf))?.into_cow()
+    } else {
+        buf.to_cow()
+    })
+}
+
+pub fn verify_hash<P: AsRef<Path>>(path: P, hash_str: &str) -> Result<()> {
+    let mut hash_bytes = [0u8; 20];
+    hex::decode_to_slice(hash_str, &mut hash_bytes)
+        .with_context(|| format!("Invalid SHA-1 '{hash_str}'"))?;
+    let file = File::open(path.as_ref())
+        .with_context(|| format!("Failed to open file '{}'", path.as_ref().display()))?;
+    let found_hash = file_sha1(file)?;
+    if found_hash.as_ref() == hash_bytes {
+        Ok(())
+    } else {
+        Err(anyhow!(
+            "Hash mismatch: expected {}, but was {}",
+            hex::encode(hash_bytes),
+            hex::encode(found_hash)
+        ))
+    }
+}

src/util/lcf.rs

@@ -56,7 +56,8 @@ pub fn generate_ldscript(obj: &ObjInfo, auto_force_files: bool) -> Result<String
 
     let mut force_active = vec![];
     for symbol in obj.symbols.iter() {
-        if symbol.flags.is_force_active() && symbol.flags.is_global() {
+        if symbol.flags.is_force_active() && symbol.flags.is_global() && !symbol.flags.is_no_write()
+        {
             force_active.push(symbol.name.clone());
         }
     }
@@ -93,7 +94,8 @@ pub fn generate_ldscript_partial(obj: &ObjInfo, auto_force_files: bool) -> Resul
 
     let mut force_active = vec![];
     for symbol in obj.symbols.iter() {
-        if symbol.flags.is_force_active() && symbol.flags.is_global() {
+        if symbol.flags.is_force_active() && symbol.flags.is_global() && !symbol.flags.is_no_write()
+        {
             force_active.push(symbol.name.clone());
         }
     }

src/util/map.rs

@@ -565,7 +565,6 @@ pub fn apply_map_file<P: AsRef<Path>>(path: P, obj: &mut ObjInfo) -> Result<()>
 
 pub fn apply_map(result: &MapInfo, obj: &mut ObjInfo) -> Result<()> {
     for (section_index, section) in obj.sections.iter_mut() {
-        log::info!("Section {}: {} ({:?})", section_index, section.name, result.sections);
         let opt = if obj.kind == ObjKind::Executable {
             result.sections.iter().find(|s| s.address == section.address as u32)
         } else {
@@ -628,6 +627,8 @@ pub fn apply_map(result: &MapInfo, obj: &mut ObjInfo) -> Result<()> {
                 align: None,
                 common: false,
                 autogenerated: false,
+                skip: false,
+                rename: None,
             });
         }
     }

src/util/mod.rs

@@ -1,3 +1,5 @@
+use std::{borrow::Cow, ops::Deref};
+
 pub mod asm;
 pub mod comment;
 pub mod config;
@@ -39,3 +41,29 @@ macro_rules! array_ref_mut {
         to_array_mut(&mut $slice[$offset..$offset + $size])
     }};
 }
+
+pub trait IntoCow<'a, B>
+where B: ToOwned + ?Sized
+{
+    fn into_cow(self) -> Cow<'a, B>;
+}
+
+pub trait ToCow<'a, B>
+where B: ToOwned + ?Sized
+{
+    fn to_cow(&'a self) -> Cow<'a, B>;
+}
+
+impl<'a, O> IntoCow<'a, <O as Deref>::Target> for O
+where
+    O: Deref + Clone + 'a,
+    <O as Deref>::Target: ToOwned<Owned = O>,
+{
+    fn into_cow(self) -> Cow<'a, <O as Deref>::Target> { Cow::Owned(self) }
+}
+
+impl<'a, B> ToCow<'a, B> for B
+where B: ToOwned + ?Sized
+{
+    fn to_cow(&'a self) -> Cow<'a, B> { Cow::Borrowed(self) }
+}

src/util/rel.rs

@@ -1,15 +1,21 @@
-use std::io::Read;
+use std::{
+    cmp::Ordering,
+    io::{Read, Seek, Write},
+};
 
-use anyhow::{anyhow, bail, ensure, Result};
+use anyhow::{anyhow, bail, ensure, Context, Result};
-use byteorder::{BigEndian, ReadBytesExt};
+use binrw::{binrw, io::NoSeek, BinRead, BinWrite};
-use object::elf;
+use itertools::Itertools;
+use object::{elf, Object, ObjectSection, ObjectSymbol};
+use tracing::warn;
 
 use crate::{
+    array_ref_mut,
     obj::{
         ObjArchitecture, ObjInfo, ObjKind, ObjRelocKind, ObjSection, ObjSectionKind, ObjSymbol,
         ObjSymbolFlagSet, ObjSymbolFlags, ObjSymbolKind,
     },
-    util::file::Reader,
+    util::{file::Reader, IntoCow},
 };
 
 /// Do not relocate anything, but accumulate the offset field for the next relocation offset calculation.
@@ -24,48 +30,130 @@ pub const R_DOLPHIN_END: u32 = 203;
 #[allow(unused)]
 pub const R_DOLPHIN_MRKREF: u32 = 204;
 
-pub fn process_rel(mut reader: Reader) -> Result<ObjInfo> {
+#[binrw]
-    let module_id = reader.read_u32::<BigEndian>()?;
+#[derive(Clone, Debug)]
-    ensure!(reader.read_u32::<BigEndian>()? == 0, "Expected 'next' to be 0");
+#[br(assert(next == 0))]
-    ensure!(reader.read_u32::<BigEndian>()? == 0, "Expected 'prev' to be 0");
+#[br(assert(prev == 0))]
-    let num_sections = reader.read_u32::<BigEndian>()?;
+#[br(assert(bss_section == 0))]
-    let section_info_offset = reader.read_u32::<BigEndian>()?;
+#[brw(assert(matches!(version, 1..=3), "Unsupported REL version {version}"))]
-    let _name_offset = reader.read_u32::<BigEndian>()?;
+pub struct RelHeader {
-    let _name_size = reader.read_u32::<BigEndian>()?;
+    /// Arbitrary identification number.
-    let version = reader.read_u32::<BigEndian>()?;
+    /// Must be unique amongst all RELs used by a game.
-    ensure!(matches!(version, 1..=3), "Unsupported REL version {}", version);
+    /// 0 is reserved for the DOL.
-    let bss_size = reader.read_u32::<BigEndian>()?;
+    pub module_id: u32,
-    let rel_offset = reader.read_u32::<BigEndian>()?;
+    /// Pointer to next module.
-    let imp_offset = reader.read_u32::<BigEndian>()?;
+    /// Filled at runtime.
-    let imp_size = reader.read_u32::<BigEndian>()?;
+    #[bw(calc = 0)]
-    let prolog_section = reader.read_u8()?;
+    pub next: u32,
-    let epilog_section = reader.read_u8()?;
+    /// Pointer to previous module.
-    let unresolved_section = reader.read_u8()?;
+    /// Filled at runtime.
-    ensure!(reader.read_u8()? == 0, "Expected 'bssSection' to be 0");
+    #[bw(calc = 0)]
-    let prolog_offset = reader.read_u32::<BigEndian>()?;
+    pub prev: u32,
-    let epilog_offset = reader.read_u32::<BigEndian>()?;
+    /// Number of sections in the file.
-    let unresolved_offset = reader.read_u32::<BigEndian>()?;
+    pub num_sections: u32,
-    let (align, bss_align) = if version >= 2 {
+    /// Offset to the start of the section table.
-        let align = reader.read_u32::<BigEndian>()?;
+    pub section_info_offset: u32,
-        let bss_align = reader.read_u32::<BigEndian>()?;
+    /// Offset in the external module name string table file.
-        (Some(align), Some(bss_align))
+    pub name_offset: u32,
-    } else {
+    /// Size of the module name in bytes.
-        (None, None)
+    pub name_size: u32,
-    };
+    /// Version number of the REL file format.
-    let fix_size = if version >= 3 { Some(reader.read_u32::<BigEndian>()?) } else { None };
+    pub version: u32,
+    /// Size of the `.bss` section.
+    pub bss_size: u32,
+    /// Offset to the start of the relocation table.
+    pub rel_offset: u32,
+    /// Offset to the start of the import table.
+    pub imp_offset: u32,
+    /// Size of the import table.
+    pub imp_size: u32,
+    /// Section containing the `_prolog` function.
+    pub prolog_section: u8,
+    /// Section containing the `_epilog` function.
+    pub epilog_section: u8,
+    /// Section containing the `_unresolved` function.
+    pub unresolved_section: u8,
+    /// Index into section table which bss is relative to.
+    /// Filled at runtime.
+    #[bw(calc = 0)]
+    pub bss_section: u8,
+    /// Offset into the section containing `_prolog`.
+    pub prolog_offset: u32,
+    /// Offset into the section containing `_epilog`.
+    pub epilog_offset: u32,
+    /// Offset into the section containing `_unresolved`.
+    pub unresolved_offset: u32,
+    /// (Version >= 2 only)
+    /// Alignment constraint on all sections.
+    #[br(if(version >= 2))]
+    #[bw(if(*version >= 2))]
+    pub align: Option<u32>,
+    /// (Version >= 2 only)
+    /// Alignment constraint on the `.bss` section.
+    #[br(if(version >= 2))]
+    #[bw(if(*version >= 2))]
+    pub bss_align: Option<u32>,
+    /// (Version >= 3 only)
+    /// If REL is linked with `OSLinkFixed` (instead of `OSLink`), the
+    /// space after this offset can be used for other purposes, like BSS.
+    #[br(if(version >= 3))]
+    #[bw(if(*version >= 3))]
+    pub fix_size: Option<u32>,
+}
 
-    let mut sections = Vec::with_capacity(num_sections as usize);
+#[binrw]
-    reader.set_position(section_info_offset as u64);
+#[derive(Copy, Clone, Debug)]
+struct RelImport {
+    module_id: u32,
+    offset: u32,
+}
+
+#[binrw]
+#[derive(Copy, Clone, Debug)]
+struct RelSectionHeader {
+    offset_and_flags: u32,
+    size: u32,
+}
+
+impl RelSectionHeader {
+    fn new(offset: u32, size: u32, exec: bool) -> Self {
+        Self { offset_and_flags: offset | (exec as u32), size }
+    }
+
+    fn offset(&self) -> u32 { self.offset_and_flags & !1 }
+
+    fn size(&self) -> u32 { self.size }
+
+    fn exec(&self) -> bool { self.offset_and_flags & 1 != 0 }
+}
+
+#[binrw]
+#[derive(Copy, Clone, Debug)]
+struct RelRelocRaw {
+    offset: u16,
+    kind: u8,
+    section: u8,
+    addend: u32,
+}
+
+pub fn process_rel_header(reader: &mut Reader) -> Result<RelHeader> {
+    RelHeader::read_be(reader).context("Failed to read REL header")
+}
+
+pub fn process_rel(reader: &mut Reader) -> Result<(RelHeader, ObjInfo)> {
+    let header = process_rel_header(reader)?;
+    let mut sections = Vec::with_capacity(header.num_sections as usize);
+    reader.set_position(header.section_info_offset as u64);
     let mut found_text = false;
     let mut total_bss_size = 0;
-    for idx in 0..num_sections {
+    for idx in 0..header.num_sections {
-        let offset = reader.read_u32::<BigEndian>()?;
+        let section = RelSectionHeader::read_be(reader)
-        let size = reader.read_u32::<BigEndian>()?;
+            .with_context(|| format!("Failed to read REL section header {}", idx))?;
+        let offset = section.offset();
+        let size = section.size();
         if size == 0 {
             continue;
         }
-        let exec = (offset & 1) == 1;
-        let offset = offset & !3;
 
         let data = if offset == 0 {
             vec![]
@@ -73,18 +161,18 @@ pub fn process_rel(mut reader: Reader) -> Result<ObjInfo> {
             let position = reader.position();
             reader.set_position(offset as u64);
             let mut data = vec![0u8; size as usize];
-            reader.read_exact(&mut data)?;
+            reader.read_exact(&mut data).with_context(|| {
+                format!("Failed to read REL section {} data with size {:#X}", idx, size)
+            })?;
             reader.set_position(position);
             data
         };
 
-        // println!("Section {} offset {:#X} size {:#X}", idx, offset, size);
-
         let (name, kind, section_known) = if offset == 0 {
             ensure!(total_bss_size == 0, "Multiple BSS sections in REL");
             total_bss_size = size;
             (".bss".to_string(), ObjSectionKind::Bss, true)
-        } else if exec {
+        } else if section.exec() {
             ensure!(!found_text, "Multiple text sections in REL");
             found_text = true;
             (".text".to_string(), ObjSectionKind::Code, true)
@@ -98,8 +186,8 @@ pub fn process_rel(mut reader: Reader) -> Result<ObjInfo> {
             size: size as u64,
             data,
             align: match offset {
-                0 => bss_align,
+                0 => header.bss_align,
-                _ => align,
+                _ => header.align,
             }
             .unwrap_or_default() as u64,
             elf_index: idx as usize,
@@ -111,10 +199,10 @@ pub fn process_rel(mut reader: Reader) -> Result<ObjInfo> {
         });
     }
     ensure!(
-        total_bss_size == bss_size,
+        total_bss_size == header.bss_size,
         "Mismatched BSS size: {:#X} != {:#X}",
         total_bss_size,
-        bss_size
+        header.bss_size
     );
 
     let mut symbols = Vec::new();
@@ -141,49 +229,45 @@ pub fn process_rel(mut reader: Reader) -> Result<ObjInfo> {
         }
         Ok(())
     };
-    add_symbol(prolog_section, prolog_offset, "_prolog")?;
+    add_symbol(header.prolog_section, header.prolog_offset, "_prolog")?;
-    add_symbol(epilog_section, epilog_offset, "_epilog")?;
+    add_symbol(header.epilog_section, header.epilog_offset, "_epilog")?;
-    add_symbol(unresolved_section, unresolved_offset, "_unresolved")?;
+    add_symbol(header.unresolved_section, header.unresolved_offset, "_unresolved")?;
 
     let mut unresolved_relocations = Vec::new();
     let mut imp_idx = 0;
-    let imp_end = (imp_offset + imp_size) as u64;
+    let imp_end = (header.imp_offset + header.imp_size) as u64;
-    reader.set_position(imp_offset as u64);
+    reader.set_position(header.imp_offset as u64);
     while reader.position() < imp_end {
-        let reloc_module_id = reader.read_u32::<BigEndian>()?;
+        let import = RelImport::read_be(reader)?;
-        let reloc_offset = reader.read_u32::<BigEndian>()?;
 
         if imp_idx == 0 {
             ensure!(
-                reloc_offset == rel_offset,
+                import.offset == header.rel_offset,
                 "imp index 0 offset mismatch: {:#X} != {:#X}",
-                reloc_offset,
+                import.offset,
-                rel_offset
+                header.rel_offset
             );
         }
         imp_idx += 1;
 
-        if reloc_module_id == module_id {
+        if import.module_id == header.module_id {
-            if let Some(fix_size) = fix_size {
+            if let Some(fix_size) = header.fix_size {
                 ensure!(
-                    fix_size == reloc_offset,
+                    fix_size == import.offset,
                     "fix_size mismatch: {:#X} != {:#X}",
                     fix_size,
-                    reloc_offset
+                    import.offset
                 );
             }
         }
 
         let position = reader.position();
-        reader.set_position(reloc_offset as u64);
+        reader.set_position(import.offset as u64);
         let mut address = 0u32;
         let mut section = u8::MAX;
         loop {
-            let offset = reader.read_u16::<BigEndian>()?;
+            let reloc = RelRelocRaw::read_be(reader)?;
-            let type_id = reader.read_u8()? as u32;
+            let kind = match reloc.kind as u32 {
-            let target_section = reader.read_u8()?;
-            let addend = reader.read_u32::<BigEndian>()?;
-            let kind = match type_id {
                 elf::R_PPC_NONE => continue,
                 elf::R_PPC_ADDR32 | elf::R_PPC_UADDR32 => ObjRelocKind::Absolute,
                 // elf::R_PPC_ADDR24 => ObjRelocKind::PpcAddr24,
@@ -199,36 +283,33 @@ pub fn process_rel(mut reader: Reader) -> Result<ObjInfo> {
                 // elf::R_PPC_REL14_BRTAKEN => ObjRelocKind::PpcRel14BrTaken,
                 // elf::R_PPC_REL14_BRNTAKEN => ObjRelocKind::PpcRel14BrnTaken,
                 R_DOLPHIN_NOP => {
-                    address += offset as u32;
+                    address += reloc.offset as u32;
                     continue;
                 }
                 R_DOLPHIN_SECTION => {
                     address = 0;
-                    section = target_section;
+                    section = reloc.section;
                     continue;
                 }
                 R_DOLPHIN_END => break,
                 // R_DOLPHIN_MRKREF => ?
                 reloc_type => bail!("Unhandled REL relocation type {reloc_type}"),
             };
-            address += offset as u32;
+            address += reloc.offset as u32;
-            unresolved_relocations.push(RelReloc {
+            let reloc = RelReloc {
                 kind,
                 section,
                 address: address & !3,
-                module_id: reloc_module_id,
+                module_id: import.module_id,
-                target_section,
+                target_section: reloc.section,
-                addend,
+                addend: reloc.addend,
-            });
+            };
+            unresolved_relocations.push(reloc);
         }
         reader.set_position(position);
     }
 
-    // let name = match name_offset {
+    log::debug!("Read REL ID {}", header.module_id);
-    //     0 => String::new(),
-    //     _ => read_string(&mut reader, name_offset as u64, name_size as usize).unwrap_or_default(),
-    // };
-    log::debug!("Read REL ID {module_id}");
     let mut obj = ObjInfo::new(
         ObjKind::Relocatable,
         ObjArchitecture::PowerPc,
@@ -236,9 +317,9 @@ pub fn process_rel(mut reader: Reader) -> Result<ObjInfo> {
         symbols,
         sections,
     );
-    obj.module_id = module_id;
+    obj.module_id = header.module_id;
     obj.unresolved_relocations = unresolved_relocations;
-    Ok(obj)
+    Ok((header, obj))
 }
 
 /// REL relocation.
@@ -258,3 +339,342 @@ pub struct RelReloc {
     /// If target module ID is 0 (DOL), this is an absolute address.
     pub addend: u32,
 }
+
+#[inline]
+fn reloc_can_be_applied(_module_id: u32, rel_reloc: &RelReloc) -> bool {
+    matches!(rel_reloc.kind, ObjRelocKind::PpcRel24 | ObjRelocKind::PpcRel14)
+}
+
+#[inline]
+fn skip_reloc(module_id: u32, rel_reloc: &RelReloc) -> bool {
+    rel_reloc.module_id == module_id
+        && rel_reloc.section == rel_reloc.target_section
+        && matches!(rel_reloc.kind, ObjRelocKind::PpcRel24 | ObjRelocKind::PpcRel14)
+}
+
+fn apply_relocation(
+    data: &mut [u8],
+    module_id: u32,
+    rel_reloc: &RelReloc,
+    unresolved: u32,
+) -> Result<()> {
+    let diff = if rel_reloc.module_id == module_id && rel_reloc.section == rel_reloc.target_section
+    {
+        rel_reloc.addend as i32 - rel_reloc.address as i32
+    } else {
+        unresolved as i32 - rel_reloc.address as i32
+    };
+    let ins_ref = array_ref_mut!(data, rel_reloc.address as usize, 4);
+    let mut ins = u32::from_be_bytes(*ins_ref);
+    match rel_reloc.kind {
+        ObjRelocKind::PpcRel24 => {
+            ensure!((-0x2000000..0x2000000).contains(&diff), "R_PPC_REL24 relocation out of range");
+            ins = (ins & !0x3fffffc) | (diff as u32 & 0x3fffffc);
+        }
+        ObjRelocKind::PpcRel14 => {
+            ensure!((-0x2000..0x2000).contains(&diff), "R_PPC_REL14 relocation out of range");
+            ins = (ins & !0xfffc) | (diff as u32 & 0xfffc);
+        }
+        kind => bail!("Unsupported relocation kind {:?}", kind),
+    }
+    *ins_ref = ins.to_be_bytes();
+    Ok(())
+}
+
+#[derive(Clone, Debug)]
+pub struct RelWriteInfo {
+    /// REL module ID.
+    pub module_id: u32,
+    /// REL version.
+    pub version: u32,
+    /// Override `name_offset` in the REL header.
+    /// Useful for matching RELs without the original string table.
+    pub name_offset: Option<u32>,
+    /// Override `name_size` in the REL header.
+    /// Useful for matching RELs without the original string table.
+    pub name_size: Option<u32>,
+    /// Override `align` in the REL header.
+    pub align: Option<u32>,
+    /// Override `bss_align` in the REL header.
+    pub bss_align: Option<u32>,
+    /// Override the number of sections in the file.
+    /// Useful for matching RELs that included debug sections.
+    pub section_count: Option<usize>,
+}
+
+const PERMITTED_SECTIONS: [&str; 7] =
+    [".init", ".text", ".ctors", ".dtors", ".rodata", ".data", ".bss"];
+
+pub fn should_write_section(section: &object::Section) -> bool {
+    matches!(section.name(), Ok(name) if PERMITTED_SECTIONS.contains(&name))
+        && section.kind() != object::SectionKind::UninitializedData
+}
+
+pub fn write_rel<W: Write>(
+    w: &mut W,
+    info: &RelWriteInfo,
+    file: &object::File,
+    mut relocations: Vec<RelReloc>,
+) -> Result<()> {
+    relocations.sort_by(|a, b| {
+        if a.module_id == 0 {
+            if b.module_id == 0 {
+                Ordering::Equal
+            } else {
+                Ordering::Greater
+            }
+        } else if a.module_id == info.module_id {
+            if b.module_id == 0 {
+                Ordering::Less
+            } else if b.module_id == info.module_id {
+                Ordering::Equal
+            } else {
+                Ordering::Greater
+            }
+        } else if b.module_id == 0 || b.module_id == info.module_id {
+            Ordering::Less
+        } else {
+            a.module_id.cmp(&b.module_id)
+        }
+        .then(a.section.cmp(&b.section))
+        .then(a.address.cmp(&b.address))
+    });
+
+    let mut apply_relocations = vec![];
+    relocations.retain(|r| {
+        if !should_write_section(
+            &file.section_by_index(object::SectionIndex(r.section as usize)).unwrap(),
+        ) {
+            return false;
+        }
+        if reloc_can_be_applied(info.module_id, r) {
+            apply_relocations.push(r.clone());
+            !skip_reloc(info.module_id, r)
+        } else {
+            true
+        }
+    });
+
+    let mut align =
+        file.sections().filter(should_write_section).map(|s| s.align() as u32).max().unwrap_or(0);
+    let bss = file.sections().find(|s| s.name() == Ok(".bss"));
+    let mut bss_align = bss.as_ref().map(|s| s.align() as u32).unwrap_or(1);
+    let mut num_sections = file.sections().count() as u32;
+
+    // Apply overrides
+    if let Some(section_count) = info.section_count {
+        if section_count != num_sections as usize {
+            warn!(from = num_sections, to = section_count, "Overriding section count");
+        }
+        num_sections = section_count as u32;
+    }
+    if info.version >= 2 {
+        if let Some(align_override) = info.align {
+            if align_override != align {
+                warn!(from = align, to = align_override, "Overriding alignment");
+            }
+            align = align_override;
+        }
+        if let Some(bss_align_override) = info.bss_align {
+            if bss_align_override != bss_align {
+                warn!(from = bss_align, to = bss_align_override, "Overriding BSS alignment");
+            }
+            bss_align = bss_align_override;
+        }
+    }
+
+    let mut header = RelHeader {
+        module_id: info.module_id,
+        num_sections,
+        section_info_offset: match info.version {
+            1 => 0x40,
+            2 => 0x48,
+            3 => 0x4C,
+            _ => bail!("Unsupported REL version {}", info.version),
+        },
+        name_offset: info.name_offset.unwrap_or(0),
+        name_size: info.name_size.unwrap_or(0),
+        version: info.version,
+        bss_size: bss.as_ref().map(|s| s.size() as u32).unwrap_or(0),
+        rel_offset: 0,
+        imp_offset: 0,
+        imp_size: 0,
+        prolog_section: 0,
+        epilog_section: 0,
+        unresolved_section: 0,
+        prolog_offset: 0,
+        epilog_offset: 0,
+        unresolved_offset: 0,
+        align: if info.version >= 2 { Some(align) } else { None },
+        bss_align: if info.version >= 2 { Some(bss_align) } else { None },
+        fix_size: None,
+    };
+    let mut offset = header.section_info_offset;
+    offset += num_sections * 8;
+    let section_data_offset = offset;
+    for section in file.sections().filter(should_write_section) {
+        let align = section.align() as u32 - 1;
+        offset = (offset + align) & !align;
+        offset += section.size() as u32;
+    }
+    header.imp_offset = offset;
+    let imp_count = relocations.iter().map(|r| r.module_id).dedup().count();
+    header.imp_size = imp_count as u32 * 8;
+    offset += header.imp_size;
+    header.rel_offset = offset;
+
+    let mut imp_entries = Vec::<RelImport>::with_capacity(imp_count);
+    let mut raw_relocations = vec![];
+    {
+        let mut address = 0u32;
+        let mut section = u8::MAX;
+        let mut last_module_id = u32::MAX;
+        for reloc in &relocations {
+            if reloc.module_id != last_module_id {
+                if last_module_id != u32::MAX {
+                    raw_relocations.push(RelRelocRaw {
+                        offset: 0,
+                        kind: R_DOLPHIN_END as u8,
+                        section: 0,
+                        addend: 0,
+                    });
+                    offset += 8;
+                }
+                imp_entries.push(RelImport { module_id: reloc.module_id, offset });
+                section = u8::MAX;
+                last_module_id = reloc.module_id;
+            }
+            if info.version >= 3
+                && header.fix_size.is_none()
+                && (reloc.module_id == 0 || reloc.module_id == info.module_id)
+            {
+                header.fix_size = Some(offset);
+            }
+            if reloc.section != section {
+                raw_relocations.push(RelRelocRaw {
+                    offset: 0,
+                    kind: R_DOLPHIN_SECTION as u8,
+                    section: reloc.section,
+                    addend: 0,
+                });
+                offset += 8;
+                address = 0;
+                section = reloc.section;
+            }
+            let mut reloc_offset = reloc.address - address;
+            while reloc_offset > 0xffff {
+                raw_relocations.push(RelRelocRaw {
+                    offset: 0xffff,
+                    kind: R_DOLPHIN_NOP as u8,
+                    section: 0,
+                    addend: 0,
+                });
+                offset += 8;
+                reloc_offset -= 0xffff;
+            }
+            raw_relocations.push(RelRelocRaw {
+                offset: reloc_offset as u16,
+                kind: match reloc.kind {
+                    ObjRelocKind::Absolute => elf::R_PPC_ADDR32,
+                    ObjRelocKind::PpcAddr16Lo => elf::R_PPC_ADDR16_LO,
+                    ObjRelocKind::PpcAddr16Hi => elf::R_PPC_ADDR16_HI,
+                    ObjRelocKind::PpcAddr16Ha => elf::R_PPC_ADDR16_HA,
+                    ObjRelocKind::PpcRel24 => elf::R_PPC_REL24,
+                    ObjRelocKind::PpcRel14 => elf::R_PPC_REL14,
+                    _ => bail!("Unsupported relocation kind {:?}", reloc.kind),
+                } as u8,
+                section: reloc.target_section,
+                addend: reloc.addend,
+            });
+            address = reloc.address;
+            offset += 8;
+        }
+    }
+    raw_relocations.push(RelRelocRaw {
+        offset: 0,
+        kind: R_DOLPHIN_END as u8,
+        section: 0,
+        addend: 0,
+    });
+    offset += 8;
+
+    for symbol in file.symbols().filter(|s| s.is_definition()) {
+        let Some(symbol_section) = symbol.section_index() else {
+            continue;
+        };
+        match symbol.name() {
+            Ok("_prolog") => {
+                header.prolog_section = symbol_section.0 as u8;
+                header.prolog_offset = symbol.address() as u32;
+            }
+            Ok("_epilog") => {
+                header.epilog_section = symbol_section.0 as u8;
+                header.epilog_offset = symbol.address() as u32;
+            }
+            Ok("_unresolved") => {
+                header.unresolved_section = symbol_section.0 as u8;
+                header.unresolved_offset = symbol.address() as u32;
+            }
+            _ => {}
+        }
+    }
+
+    let mut w = NoSeek::new(w);
+    header.write_be(&mut w)?;
+    ensure!(w.stream_position()? as u32 == header.section_info_offset);
+    let mut current_data_offset = section_data_offset;
+    for section_index in 0..num_sections {
+        let Ok(section) = file.section_by_index(object::SectionIndex(section_index as usize))
+        else {
+            RelSectionHeader::new(0, 0, false).write_be(&mut w)?;
+            continue;
+        };
+        if matches!(section.name(), Ok(name) if PERMITTED_SECTIONS.contains(&name)) {
+            let mut offset = 0;
+            if section.kind() != object::SectionKind::UninitializedData {
+                let align = section.align() as u32 - 1;
+                current_data_offset = (current_data_offset + align) & !align;
+                offset = current_data_offset;
+                current_data_offset += section.size() as u32;
+            }
+            RelSectionHeader::new(
+                offset,
+                section.size() as u32,
+                section.kind() == object::SectionKind::Text,
+            )
+            .write_be(&mut w)?;
+        } else {
+            RelSectionHeader::new(0, 0, false).write_be(&mut w)?;
+        }
+    }
+    ensure!(w.stream_position()? as u32 == section_data_offset);
+    for section in file.sections().filter(should_write_section) {
+        fn calculate_padding(position: u64, align: u64) -> u64 {
+            let align = align - 1;
+            ((position + align) & !align) - position
+        }
+        let position = w.stream_position()?;
+        w.write_all(&vec![0; calculate_padding(position, section.align()) as usize])?;
+
+        let section_index = section.index().0 as u8;
+        let mut section_data = section.uncompressed_data()?;
+        if apply_relocations.iter().any(|r| r.section == section_index) {
+            let mut data = section_data.into_owned();
+            for reloc in apply_relocations.iter().filter(|r| r.section == section_index) {
+                apply_relocation(&mut data, info.module_id, reloc, header.unresolved_offset)?;
+            }
+            section_data = data.into_cow();
+        }
+        w.write_all(&section_data)?;
+    }
+    ensure!(w.stream_position()? as u32 == header.imp_offset);
+    for entry in imp_entries {
+        entry.write_be(&mut w)?;
+    }
+    ensure!(w.stream_position()? as u32 == header.rel_offset);
+    for reloc in raw_relocations {
+        reloc.write_be(&mut w)?;
+    }
+    ensure!(w.stream_position()? as u32 == offset);
+    Ok(())
+}

src/util/split.rs

@@ -1,5 +1,5 @@
 use std::{
-    cmp::min,
+    cmp::{min, Ordering},
     collections::{BTreeMap, HashMap, HashSet},
 };
 
@@ -85,6 +85,8 @@ fn split_ctors_dtors(obj: &mut ObjInfo, start: SectionAddress, end: SectionAddre
                     align: None,
                     common: false,
                     autogenerated: true,
+                    skip: false,
+                    rename: None,
                 });
             }
             if function_split.is_none() {
@@ -95,6 +97,8 @@ fn split_ctors_dtors(obj: &mut ObjInfo, start: SectionAddress, end: SectionAddre
                     align: None,
                     common: false,
                     autogenerated: true,
+                    skip: false,
+                    rename: None,
                 });
             }
         }
@@ -263,6 +267,8 @@ fn split_extabindex(obj: &mut ObjInfo, start: SectionAddress) -> Result<()> {
                     align: None,
                     common: false,
                     autogenerated: true,
+                    skip: false,
+                    rename: None,
                 });
             }
             if extab_split.is_none() {
@@ -274,6 +280,8 @@ fn split_extabindex(obj: &mut ObjInfo, start: SectionAddress) -> Result<()> {
                     align: None,
                     common: false,
                     autogenerated: true,
+                    skip: false,
+                    rename: None,
                 });
             }
             if function_split.is_none() {
@@ -285,6 +293,8 @@ fn split_extabindex(obj: &mut ObjInfo, start: SectionAddress) -> Result<()> {
                     align: None,
                     common: false,
                     autogenerated: true,
+                    skip: false,
+                    rename: None,
                 });
             }
         }
@@ -374,6 +384,8 @@ fn create_gap_splits(obj: &mut ObjInfo) -> Result<()> {
                     align: None,
                     common: false,
                     autogenerated: true,
+                    skip: false,
+                    rename: None,
                 });
                 current_address = new_split_end;
                 continue;
@@ -485,6 +497,131 @@ fn validate_splits(obj: &ObjInfo) -> Result<()> {
     Ok(())
 }
 
+/// Add padding symbols to fill in gaps between splits and symbols.
+fn add_padding_symbols(obj: &mut ObjInfo) -> Result<()> {
+    for (section_index, section, addr, _split) in obj.sections.all_splits() {
+        if section.name == ".ctors" || section.name == ".dtors" {
+            continue;
+        }
+
+        if obj
+            .symbols
+            .kind_at_section_address(section_index, addr, match section.kind {
+                ObjSectionKind::Code => ObjSymbolKind::Function,
+                ObjSectionKind::Data => ObjSymbolKind::Object,
+                ObjSectionKind::ReadOnlyData => ObjSymbolKind::Object,
+                ObjSectionKind::Bss => ObjSymbolKind::Object,
+            })?
+            .is_none()
+        {
+            let next_symbol_address = obj
+                .symbols
+                .for_section_range(section_index, addr + 1..)
+                .find(|&(_, s)| s.size_known && s.size > 0)
+                .map(|(_, s)| s.address)
+                .unwrap_or(section.address + section.size);
+            let symbol_name = format!(
+                "pad_{:02}_{:08X}_{}",
+                section_index,
+                addr,
+                section.name.trim_start_matches('.')
+            );
+            log::debug!("Adding padding symbol {} at {:#010X}", symbol_name, addr);
+            obj.symbols.add_direct(ObjSymbol {
+                name: symbol_name,
+                demangled_name: None,
+                address: addr as u64,
+                section: Some(section_index),
+                size: next_symbol_address - addr as u64,
+                size_known: true,
+                flags: ObjSymbolFlagSet(
+                    ObjSymbolFlags::Local | ObjSymbolFlags::ForceActive | ObjSymbolFlags::NoWrite,
+                ),
+                kind: match section.kind {
+                    ObjSectionKind::Code => ObjSymbolKind::Function,
+                    ObjSectionKind::Data | ObjSectionKind::ReadOnlyData | ObjSectionKind::Bss => {
+                        ObjSymbolKind::Object
+                    }
+                },
+                align: None,
+                data_kind: Default::default(),
+            })?;
+        }
+    }
+
+    // Add padding symbols for gaps between symbols
+    for (section_index, section) in obj.sections.iter() {
+        if section.name == ".ctors" || section.name == ".dtors" {
+            continue;
+        }
+
+        let mut to_add = vec![];
+        let mut iter = obj
+            .symbols
+            .for_section(section_index)
+            .filter(|(_, s)| s.size_known && s.size > 0)
+            .peekable();
+        while let (Some((_, symbol)), Some(&(_, next_symbol))) = (iter.next(), iter.peek()) {
+            let aligned_end =
+                align_up((symbol.address + symbol.size) as u32, next_symbol.align.unwrap_or(1));
+            match aligned_end.cmp(&(next_symbol.address as u32)) {
+                Ordering::Less => {
+                    let symbol_name = format!(
+                        "gap_{:02}_{:08X}_{}",
+                        section_index,
+                        aligned_end,
+                        section.name.trim_start_matches('.')
+                    );
+                    log::debug!("Adding gap symbol {} at {:#010X}", symbol_name, aligned_end);
+                    to_add.push(ObjSymbol {
+                        name: symbol_name,
+                        demangled_name: None,
+                        address: aligned_end as u64,
+                        section: Some(section_index),
+                        size: next_symbol.address - aligned_end as u64,
+                        size_known: true,
+                        flags: ObjSymbolFlagSet(
+                            ObjSymbolFlags::Global
+                                | ObjSymbolFlags::ForceActive
+                                | ObjSymbolFlags::NoWrite,
+                        ),
+                        kind: match section.kind {
+                            ObjSectionKind::Code => ObjSymbolKind::Function,
+                            ObjSectionKind::Data
+                            | ObjSectionKind::ReadOnlyData
+                            | ObjSectionKind::Bss => ObjSymbolKind::Object,
+                        },
+                        align: None,
+                        data_kind: Default::default(),
+                    });
+                }
+                Ordering::Equal => {}
+                Ordering::Greater => {
+                    bail!(
+                        "Symbol {} ({:#010X}..{:#010X}) overlaps with symbol {} ({:#010X}..{:#010X}, align {})",
+                        symbol.name,
+                        symbol.address,
+                        symbol.address + symbol.size,
+                        next_symbol.name,
+                        next_symbol.address,
+                        next_symbol.address + next_symbol.size,
+                        next_symbol.align.unwrap_or(1)
+                    );
+                }
+            }
+        }
+        drop(iter);
+
+        for symbol in to_add {
+            obj.symbols.add_direct(symbol)?;
+        }
+    }
+    Ok(())
+}
+
+#[inline]
+const fn align_up(value: u32, align: u32) -> u32 { (value + (align - 1)) & !(align - 1) }
+
 /// Perform any necessary adjustments to allow relinking.
 /// This includes:
 /// - Ensuring .ctors & .dtors entries are split with their associated function
@@ -526,6 +663,9 @@ pub fn update_splits(obj: &mut ObjInfo, common_start: Option<u32>) -> Result<()>
     // Ensure splits don't overlap symbols or each other
     validate_splits(obj)?;
 
+    // Add symbols to beginning of any split that doesn't start with a symbol
+    add_padding_symbols(obj)?;
+
     // Resolve link order
     obj.link_order = resolve_link_order(obj)?;
 
@@ -677,6 +817,12 @@ pub fn split_obj(obj: &ObjInfo) -> Result<Vec<ObjInfo>> {
                 file_end = min(next_addr, section_end);
             }
 
+            // Skip over this data
+            if split.skip {
+                current_address = file_end;
+                continue;
+            }
+
             let file = name_to_obj
                 .get(&split.unit)
                 .and_then(|&idx| objects.get_mut(idx))
@@ -792,13 +938,8 @@ pub fn split_obj(obj: &ObjInfo) -> Result<Vec<ObjInfo>> {
                         ..(file_end.address as u64 - section.address) as usize]
                         .to_vec(),
                 };
-                let name = if let Some(name) = obj.named_sections.get(&current_address.address) {
-                    name.clone()
-                } else {
-                    section.name.clone()
-                };
                 file.sections.push(ObjSection {
-                    name,
+                    name: split.rename.as_ref().unwrap_or(&section.name).clone(),
                     kind: section.kind,
                     address: 0,
                     size: file_end.address as u64 - current_address.address as u64,
@@ -1032,7 +1173,6 @@ pub fn end_for_section(obj: &ObjInfo, section_index: usize) -> Result<SectionAdd
         && section.data[section.data.len() - 4..] == [0u8; 4]
     {
         section_end -= 4;
-        return Ok(SectionAddress::new(section_index, section_end));
     }
     loop {
         let last_symbol = obj