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Support PPC64 ELFs (PS3); refactor relocation processing

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This commit is contained in:
Luke Street
2025-07-21 21:01:03 -06:00
parent 8fac63c42c
commit 00ad0d8094
10 changed files with 335 additions and 195 deletions
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92
objdiff-core/src/arch/mips.rs
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@@ -14,7 +14,7 @@ use rabbitizer::{
};
use crate::{
arch::Arch,
arch::{Arch, RelocationOverride, RelocationOverrideTarget},
diff::{DiffObjConfig, MipsAbi, MipsInstrCategory, display::InstructionPart},
obj::{
InstructionArg, InstructionArgValue, InstructionRef, Relocation, RelocationFlags,
@@ -225,53 +225,67 @@ impl Arch for ArchMips {
Ok(())
}
fn implcit_addend(
fn relocation_override(
&self,
file: &object::File<'_>,
section: &object::Section,
address: u64,
reloc: &object::Relocation,
flags: RelocationFlags,
) -> Result<Option<i64>> {
// Check for paired R_MIPS_HI16 and R_MIPS_LO16 relocations.
if let RelocationFlags::Elf(elf::R_MIPS_HI16 | elf::R_MIPS_LO16) = flags {
if let Some(addend) = self
.paired_relocations
.get(section.index().0)
.and_then(|m| m.get(&address).copied())
{
return Ok(Some(addend));
}
}
relocation: &object::Relocation,
) -> Result<Option<RelocationOverride>> {
match relocation.flags() {
// Handle ELF implicit relocations
object::RelocationFlags::Elf { r_type } => {
if relocation.has_implicit_addend() {
// Check for paired R_MIPS_HI16 and R_MIPS_LO16 relocations.
if let elf::R_MIPS_HI16 | elf::R_MIPS_LO16 = r_type {
if let Some(addend) = self
.paired_relocations
.get(section.index().0)
.and_then(|m| m.get(&address).copied())
{
return Ok(Some(RelocationOverride {
target: RelocationOverrideTarget::Keep,
addend,
}));
}
}
let data = section.data()?;
let code = data[address as usize..address as usize + 4].try_into()?;
let addend = self.endianness.read_u32_bytes(code);
Ok(Some(match flags {
RelocationFlags::Elf(elf::R_MIPS_32) => addend as i64,
RelocationFlags::Elf(elf::R_MIPS_26) => ((addend & 0x03FFFFFF) << 2) as i64,
RelocationFlags::Elf(elf::R_MIPS_HI16) => ((addend & 0x0000FFFF) << 16) as i32 as i64,
RelocationFlags::Elf(elf::R_MIPS_LO16 | elf::R_MIPS_GOT16 | elf::R_MIPS_CALL16) => {
(addend & 0x0000FFFF) as i16 as i64
}
RelocationFlags::Elf(elf::R_MIPS_GPREL16 | elf::R_MIPS_LITERAL) => {
let object::RelocationTarget::Symbol(idx) = reloc.target() else {
bail!("Unsupported R_MIPS_GPREL16 relocation against a non-symbol");
};
let sym = file.symbol_by_index(idx)?;
let data = section.data()?;
let code = self
.endianness
.read_u32_bytes(data[address as usize..address as usize + 4].try_into()?);
let addend = match r_type {
elf::R_MIPS_32 => code as i64,
elf::R_MIPS_26 => ((code & 0x03FFFFFF) << 2) as i64,
elf::R_MIPS_HI16 => ((code & 0x0000FFFF) << 16) as i32 as i64,
elf::R_MIPS_LO16 | elf::R_MIPS_GOT16 | elf::R_MIPS_CALL16 => {
(code & 0x0000FFFF) as i16 as i64
}
elf::R_MIPS_GPREL16 | elf::R_MIPS_LITERAL => {
let object::RelocationTarget::Symbol(idx) = relocation.target() else {
bail!("Unsupported R_MIPS_GPREL16 relocation against a non-symbol");
};
let sym = file.symbol_by_index(idx)?;
// if the symbol we are relocating against is in a local section we need to add
// the ri_gp_value from .reginfo to the addend.
if sym.section().index().is_some() {
((addend & 0x0000FFFF) as i16 as i64) + self.ri_gp_value as i64
// if the symbol we are relocating against is in a local section we need to add
// the ri_gp_value from .reginfo to the addend.
if sym.section().index().is_some() {
((code & 0x0000FFFF) as i16 as i64) + self.ri_gp_value as i64
} else {
(code & 0x0000FFFF) as i16 as i64
}
}
elf::R_MIPS_PC16 => 0, // PC-relative relocation
R_MIPS15_S3 => ((code & 0x001FFFC0) >> 3) as i64,
flags => bail!("Unsupported MIPS implicit relocation {flags:?}"),
};
Ok(Some(RelocationOverride { target: RelocationOverrideTarget::Keep, addend }))
} else {
(addend & 0x0000FFFF) as i16 as i64
Ok(None)
}
}
RelocationFlags::Elf(elf::R_MIPS_PC16) => 0, // PC-relative relocation
RelocationFlags::Elf(R_MIPS15_S3) => ((addend & 0x001FFFC0) >> 3) as i64,
flags => bail!("Unsupported MIPS implicit relocation {flags:?}"),
}))
_ => Ok(None),
}
}
fn demangle(&self, name: &str) -> Option<String> {