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PPC: Reimplement pooled data reference calculation (#167)

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* PPC: Calculate pooled relocations

Reimplements #140

The relocations are now generated when the object is first read in `parse`, right after the real relocations are read.

`resolve_relocation` was changed to take `obj.symbols` instead of `obj` as an argument, because `obj` itself doesn't exist yet at the time the relocations are being read.

* Improve readability of PPC pool relocs code

* Fix regression causing extern pool relocs to be ignored

* Fix showing incorrect diff when diffing weak stripped symbol with an addend

This is a regression that was introduced by #158 diffing addends in addition to symbol names. But it's not really a bug in that PR, rather it seems like I simply never added the offset into the addend when creating a fake pool relocation for an extern symbol. So this commit fixes that root issue instead.

* Add PPC "Calculate pooled data references" option

* Fix objdiff-wasm compilation errors

* Update PPC test snapshots
This commit is contained in:
LagoLunatic
2025-03-04 22:40:34 -05:00
committed by GitHub
parent 1cdfa1e857
commit cf5fc54cfa
10 changed files with 429 additions and 295 deletions
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43
objdiff-core/src/obj/read.rs
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@@ -6,7 +6,7 @@ use alloc::{
};
use core::cmp::Ordering;
use anyhow::{bail, ensure, Context, Result};
use anyhow::{anyhow, bail, ensure, Context, Result};
use object::{Object as _, ObjectSection as _, ObjectSymbol as _};
use crate::{
@@ -421,6 +421,44 @@ fn map_relocations(
Ok(())
}
fn calculate_pooled_relocations(
arch: &dyn Arch,
sections: &mut [Section],
symbols: &[Symbol],
) -> Result<()> {
for (section_index, section) in sections.iter_mut().enumerate() {
if section.kind != SectionKind::Code {
continue;
}
let mut fake_pool_relocs = Vec::new();
for symbol in symbols {
if symbol.section != Some(section_index) {
continue;
}
if symbol.kind != SymbolKind::Function {
continue;
}
let code =
section.data_range(symbol.address, symbol.size as usize).ok_or_else(|| {
anyhow!(
"Symbol data out of bounds: {:#x}..{:#x}",
symbol.address,
symbol.address + symbol.size
)
})?;
fake_pool_relocs.append(&mut arch.generate_pooled_relocations(
symbol.address,
code,
&section.relocations,
symbols,
));
}
section.relocations.append(&mut fake_pool_relocs);
section.relocations.sort_by_key(|r| r.address);
}
Ok(())
}
fn parse_line_info(
obj_file: &object::File,
sections: &mut [Section],
@@ -812,6 +850,9 @@ pub fn parse(data: &[u8], config: &DiffObjConfig) -> Result<Object> {
let (mut symbols, symbol_indices) =
map_symbols(arch.as_ref(), &obj_file, &sections, &section_indices, split_meta.as_ref())?;
map_relocations(arch.as_ref(), &obj_file, &mut sections, &section_indices, &symbol_indices)?;
if config.ppc_calculate_pool_relocations {
calculate_pooled_relocations(arch.as_ref(), &mut sections, &symbols)?;
}
parse_line_info(&obj_file, &mut sections, &section_indices, data)?;
if config.combine_data_sections || config.combine_text_sections {
combine_sections(&mut sections, &mut symbols, config)?;