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Improve local branch relocation handling

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Reworks the local-branch handling logic to be more
unified: scan_instructions does all the work up front,
and process_instruction / display_instruction can
simply use the calculated branch destination instead
of performing their own is-relocation-target-
function-local checks.

(Hopefully) Fixes #192
This commit is contained in:
Luke Street
2025-05-07 22:53:10 -06:00
parent 34220a8e26
commit 0c48d711c7
21 changed files with 1253 additions and 226 deletions
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57
objdiff-core/src/arch/x86.rs
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@@ -11,9 +11,7 @@ use object::{Endian as _, Object as _, ObjectSection as _, pe};
use crate::{
arch::Arch,
diff::{DiffObjConfig, X86Formatter, display::InstructionPart},
obj::{
InstructionRef, Relocation, RelocationFlags, ResolvedInstructionRef, ScannedInstruction,
},
obj::{InstructionRef, Relocation, RelocationFlags, ResolvedInstructionRef},
};
#[derive(Debug)]
@@ -86,14 +84,14 @@ impl ArchX86 {
const DATA_OPCODE: u16 = u16::MAX - 1;
impl Arch for ArchX86 {
fn scan_instructions(
fn scan_instructions_internal(
&self,
address: u64,
code: &[u8],
_section_index: usize,
relocations: &[Relocation],
_diff_config: &DiffObjConfig,
) -> Result<Vec<ScannedInstruction>> {
) -> Result<Vec<InstructionRef>> {
let mut out = Vec::with_capacity(code.len() / 2);
let mut decoder = self.decoder(code, address);
let mut instruction = Instruction::default();
@@ -112,12 +110,10 @@ impl Arch for ArchX86 {
})?;
if decoder.set_position(decoder.position() + size).is_ok() {
decoder.set_ip(address + size as u64);
out.push(ScannedInstruction {
ins_ref: InstructionRef {
address,
size: size as u8,
opcode: DATA_OPCODE,
},
out.push(InstructionRef {
address,
size: size as u8,
opcode: DATA_OPCODE,
branch_dest: None,
});
reloc_iter.next();
@@ -134,12 +130,10 @@ impl Arch for ArchX86 {
OpKind::NearBranch64 => Some(instruction.near_branch64()),
_ => None,
};
out.push(ScannedInstruction {
ins_ref: InstructionRef {
address,
size: instruction.len() as u8,
opcode: instruction.mnemonic() as u16,
},
out.push(InstructionRef {
address,
size: instruction.len() as u8,
opcode: instruction.mnemonic() as u16,
branch_dest,
});
}
@@ -457,15 +451,16 @@ mod test {
0xc7, 0x85, 0x68, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00, 0x8b, 0x04, 0x85, 0x00,
0x00, 0x00, 0x00,
];
let scanned = arch.scan_instructions(0, &code, 0, &[], &DiffObjConfig::default()).unwrap();
let scanned =
arch.scan_instructions_internal(0, &code, 0, &[], &DiffObjConfig::default()).unwrap();
assert_eq!(scanned.len(), 2);
assert_eq!(scanned[0].ins_ref.address, 0);
assert_eq!(scanned[0].ins_ref.size, 10);
assert_eq!(scanned[0].ins_ref.opcode, iced_x86::Mnemonic::Mov as u16);
assert_eq!(scanned[0].address, 0);
assert_eq!(scanned[0].size, 10);
assert_eq!(scanned[0].opcode, iced_x86::Mnemonic::Mov as u16);
assert_eq!(scanned[0].branch_dest, None);
assert_eq!(scanned[1].ins_ref.address, 10);
assert_eq!(scanned[1].ins_ref.size, 7);
assert_eq!(scanned[1].ins_ref.opcode, iced_x86::Mnemonic::Mov as u16);
assert_eq!(scanned[1].address, 10);
assert_eq!(scanned[1].size, 7);
assert_eq!(scanned[1].opcode, iced_x86::Mnemonic::Mov as u16);
assert_eq!(scanned[1].branch_dest, None);
}
@@ -477,7 +472,7 @@ mod test {
let mut parts = Vec::new();
arch.display_instruction(
ResolvedInstructionRef {
ins_ref: InstructionRef { address: 0x1234, size: 10, opcode },
ins_ref: InstructionRef { address: 0x1234, size: 10, opcode, branch_dest: None },
code: &code,
..Default::default()
},
@@ -513,7 +508,7 @@ mod test {
let mut parts = Vec::new();
arch.display_instruction(
ResolvedInstructionRef {
ins_ref: InstructionRef { address: 0x1234, size: 10, opcode },
ins_ref: InstructionRef { address: 0x1234, size: 10, opcode, branch_dest: None },
code: &code,
relocation: Some(ResolvedRelocation {
relocation: &Relocation {
@@ -558,7 +553,7 @@ mod test {
let mut parts = Vec::new();
arch.display_instruction(
ResolvedInstructionRef {
ins_ref: InstructionRef { address: 0x1234, size: 7, opcode },
ins_ref: InstructionRef { address: 0x1234, size: 7, opcode, branch_dest: None },
code: &code,
relocation: Some(ResolvedRelocation {
relocation: &Relocation {
@@ -601,7 +596,7 @@ mod test {
let mut parts = Vec::new();
arch.display_instruction(
ResolvedInstructionRef {
ins_ref: InstructionRef { address: 0x1234, size: 5, opcode },
ins_ref: InstructionRef { address: 0x1234, size: 5, opcode, branch_dest: None },
code: &code,
relocation: Some(ResolvedRelocation {
relocation: &Relocation {
@@ -632,7 +627,7 @@ mod test {
let mut parts = Vec::new();
arch.display_instruction(
ResolvedInstructionRef {
ins_ref: InstructionRef { address: 0x1234, size: 6, opcode },
ins_ref: InstructionRef { address: 0x1234, size: 6, opcode, branch_dest: None },
code: &code,
relocation: Some(ResolvedRelocation {
relocation: &Relocation {
@@ -671,7 +666,7 @@ mod test {
let mut parts = Vec::new();
arch.display_instruction(
ResolvedInstructionRef {
ins_ref: InstructionRef { address: 0x1234, size: 7, opcode },
ins_ref: InstructionRef { address: 0x1234, size: 7, opcode, branch_dest: None },
code: &code,
relocation: Some(ResolvedRelocation {
relocation: &Relocation {
@@ -710,7 +705,7 @@ mod test {
let mut parts = Vec::new();
arch.display_instruction(
ResolvedInstructionRef {
ins_ref: InstructionRef { address: 0x1234, size: 5, opcode },
ins_ref: InstructionRef { address: 0x1234, size: 5, opcode, branch_dest: None },
code: &code,
relocation: Some(ResolvedRelocation {
relocation: &Relocation {