Experimental ARM64 support

Based on yaxpeax-arm, but with a heavy dose of
custom code to work around its limitations.

Please report any issues or unhandled relocations.

objdiff-core/src/arch/arm.rs

@@ -124,11 +124,9 @@ impl ObjArch for ObjArchArm {
             .get(&SectionIndex(section_index))
             .map(|x| x.as_slice())
             .unwrap_or(&fallback_mappings);
-        let first_mapping_idx =
-            match mapping_symbols.binary_search_by_key(&start_addr, |x| x.address) {
-                Ok(idx) => idx,
-                Err(idx) => idx - 1,
-            };
+        let first_mapping_idx = mapping_symbols
+            .binary_search_by_key(&start_addr, |x| x.address)
+            .unwrap_or_else(|idx| idx - 1);
         let first_mapping = mapping_symbols[first_mapping_idx].mapping;
 
         let mut mappings_iter =
@@ -215,7 +213,7 @@ impl ObjArch for ObjArchArm {
                 address: address as u64,
                 size: (parser.address - address) as u8,
                 op: ins.opcode_id(),
-                mnemonic: parsed_ins.mnemonic.to_string(),
+                mnemonic: Cow::Borrowed(parsed_ins.mnemonic),
                 args,
                 reloc,
                 branch_dest,
@@ -234,7 +232,7 @@ impl ObjArch for ObjArchArm {
         section: &ObjSection,
         address: u64,
         reloc: &Relocation,
-    ) -> anyhow::Result<i64> {
+    ) -> Result<i64> {
         let address = address as usize;
         Ok(match reloc.flags() {
             // ARM calls

objdiff-core/src/arch/mips.rs

@@ -119,7 +119,7 @@ impl ObjArch for ObjArchMips {
             let op = instruction.unique_id as u16;
             ops.push(op);
 
-            let mnemonic = instruction.opcode_name().to_string();
+            let mnemonic = instruction.opcode_name();
             let is_branch = instruction.is_branch();
             let branch_offset = instruction.branch_offset();
             let mut branch_dest = if is_branch {
@@ -202,7 +202,7 @@ impl ObjArch for ObjArchMips {
                 address: cur_addr as u64,
                 size: 4,
                 op,
-                mnemonic,
+                mnemonic: Cow::Borrowed(mnemonic),
                 args,
                 reloc: reloc.cloned(),
                 branch_dest,

objdiff-core/src/arch/mod.rs

@@ -12,6 +12,8 @@ use crate::{
 
 #[cfg(feature = "arm")]
 mod arm;
+#[cfg(feature = "arm64")]
+mod arm64;
 #[cfg(feature = "mips")]
 pub mod mips;
 #[cfg(feature = "ppc")]
@@ -165,6 +167,8 @@ pub fn new_arch(object: &File) -> Result<Box<dyn ObjArch>> {
         Architecture::I386 | Architecture::X86_64 => Box::new(x86::ObjArchX86::new(object)?),
         #[cfg(feature = "arm")]
         Architecture::Arm => Box::new(arm::ObjArchArm::new(object)?),
+        #[cfg(feature = "arm64")]
+        Architecture::Aarch64 => Box::new(arm64::ObjArchArm64::new(object)?),
         arch => bail!("Unsupported architecture: {arch:?}"),
     })
 }

objdiff-core/src/arch/ppc.rs

@@ -143,7 +143,7 @@ impl ObjArch for ObjArchPpc {
             insts.push(ObjIns {
                 address: cur_addr as u64,
                 size: 4,
-                mnemonic: simplified.mnemonic.to_string(),
+                mnemonic: Cow::Borrowed(simplified.mnemonic),
                 args,
                 reloc: reloc.cloned(),
                 op: ins.op as u16,

objdiff-core/src/arch/x86.rs

@@ -51,7 +51,7 @@ impl ObjArch for ObjArchX86 {
                 address: 0,
                 size: 0,
                 op: 0,
-                mnemonic: String::new(),
+                mnemonic: Cow::Borrowed("<invalid>"),
                 args: vec![],
                 reloc: None,
                 branch_dest: None,
@@ -76,7 +76,7 @@ impl ObjArch for ObjArchX86 {
                 address,
                 size: instruction.len() as u8,
                 op,
-                mnemonic: String::new(),
+                mnemonic: Cow::Borrowed("<invalid>"),
                 args: vec![],
                 reloc: reloc.cloned(),
                 branch_dest: None,
@@ -242,7 +242,8 @@ impl FormatterOutput for InstructionFormatterOutput {
 
     fn write_mnemonic(&mut self, _instruction: &Instruction, text: &str) {
         self.formatted.push_str(text);
-        self.ins.mnemonic = text.to_string();
+        // TODO: can iced-x86 guarantee 'static here?
+        self.ins.mnemonic = Cow::Owned(text.to_string());
     }
 
     fn write_number(

objdiff-core/src/bindings/diff.rs

@@ -132,7 +132,7 @@ impl Instruction {
             address: instruction.address,
             size: instruction.size as u32,
             opcode: instruction.op as u32,
-            mnemonic: instruction.mnemonic.clone(),
+            mnemonic: instruction.mnemonic.to_string(),
             formatted: instruction.formatted.clone(),
             arguments: instruction.args.iter().map(Argument::new).collect(),
             relocation: instruction.reloc.as_ref().map(|reloc| Relocation::new(object, reloc)),

objdiff-core/src/obj/mod.rs

@@ -103,7 +103,7 @@ pub struct ObjIns {
     pub address: u64,
     pub size: u8,
     pub op: u16,
-    pub mnemonic: String,
+    pub mnemonic: Cow<'static, str>,
     pub args: Vec<ObjInsArg>,
     pub reloc: Option<ObjReloc>,
     pub branch_dest: Option<u64>,