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Move all architecture-specific code into modules

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No more scattered relocation handling and
feature checks. Everything will go through
the ObjArch trait, which makes it easier
to add new architectures going forward.
This commit is contained in:
Luke Street
2024-03-17 12:06:18 -06:00
parent bbe49eb8b4
commit 9df98f263e
15 changed files with 744 additions and 755 deletions
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166
objdiff-core/src/obj/read.rs
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@@ -5,15 +5,16 @@ use byteorder::{BigEndian, ReadBytesExt};
use filetime::FileTime;
use flagset::Flags;
use object::{
elf, pe, Architecture, BinaryFormat, Endian, File, Object, ObjectSection, ObjectSymbol,
RelocationFlags, RelocationTarget, SectionIndex, SectionKind, Symbol, SymbolKind, SymbolScope,
SymbolSection,
BinaryFormat, File, Object, ObjectSection, ObjectSymbol, RelocationTarget, SectionIndex,
SectionKind, Symbol, SymbolKind, SymbolScope, SymbolSection,
};
use crate::obj::{
split_meta::{SplitMeta, SPLITMETA_SECTION},
ObjArchitecture, ObjInfo, ObjReloc, ObjRelocKind, ObjSection, ObjSectionKind, ObjSymbol,
ObjSymbolFlagSet, ObjSymbolFlags,
use crate::{
arch::{new_arch, ObjArch},
obj::{
split_meta::{SplitMeta, SPLITMETA_SECTION},
ObjInfo, ObjReloc, ObjSection, ObjSectionKind, ObjSymbol, ObjSymbolFlagSet, ObjSymbolFlags,
},
};
fn to_obj_section_kind(kind: SectionKind) -> Option<ObjSectionKind> {
@@ -26,6 +27,7 @@ fn to_obj_section_kind(kind: SectionKind) -> Option<ObjSectionKind> {
}
fn to_obj_symbol(
arch: &dyn ObjArch,
obj_file: &File<'_>,
symbol: &Symbol<'_, '_>,
addend: i64,
@@ -59,15 +61,7 @@ fn to_obj_symbol(
} else {
symbol.address()
};
let mut demangled_name = None;
#[cfg(feature = "ppc")]
if obj_file.architecture() == Architecture::PowerPc {
demangled_name = cwdemangle::demangle(name, &Default::default());
}
#[cfg(feature = "x86")]
if matches!(obj_file.format(), BinaryFormat::Coff | BinaryFormat::Pe) && name.starts_with('?') {
demangled_name = msvc_demangler::demangle(name, msvc_demangler::DemangleFlags::llvm()).ok();
}
let demangled_name = arch.demangle(name);
// Find the virtual address for the symbol if available
let virtual_address = split_meta
.and_then(|m| m.virtual_addresses.as_ref())
@@ -129,6 +123,7 @@ fn filter_sections(obj_file: &File<'_>, split_meta: Option<&SplitMeta>) -> Resul
}
fn symbols_by_section(
arch: &dyn ObjArch,
obj_file: &File<'_>,
section: &ObjSection,
split_meta: Option<&SplitMeta>,
@@ -147,7 +142,7 @@ fn symbols_by_section(
continue;
}
}
result.push(to_obj_symbol(obj_file, &symbol, 0, split_meta)?);
result.push(to_obj_symbol(arch, obj_file, &symbol, 0, split_meta)?);
}
}
}
@@ -165,15 +160,20 @@ fn symbols_by_section(
Ok(result)
}
fn common_symbols(obj_file: &File<'_>, split_meta: Option<&SplitMeta>) -> Result<Vec<ObjSymbol>> {
fn common_symbols(
arch: &dyn ObjArch,
obj_file: &File<'_>,
split_meta: Option<&SplitMeta>,
) -> Result<Vec<ObjSymbol>> {
obj_file
.symbols()
.filter(Symbol::is_common)
.map(|symbol| to_obj_symbol(obj_file, &symbol, 0, split_meta))
.map(|symbol| to_obj_symbol(arch, obj_file, &symbol, 0, split_meta))
.collect::<Result<Vec<ObjSymbol>>>()
}
fn find_section_symbol(
arch: &dyn ObjArch,
obj_file: &File<'_>,
target: &Symbol<'_, '_>,
address: u64,
@@ -197,7 +197,7 @@ fn find_section_symbol(
}
continue;
}
return to_obj_symbol(obj_file, &symbol, 0, split_meta);
return to_obj_symbol(arch, obj_file, &symbol, 0, split_meta);
}
let (name, offset) = closest_symbol
.and_then(|s| s.name().map(|n| (n, s.address())).ok())
@@ -221,7 +221,7 @@ fn find_section_symbol(
}
fn relocations_by_section(
arch: ObjArchitecture,
arch: &dyn ObjArch,
obj_file: &File<'_>,
section: &ObjSection,
split_meta: Option<&SplitMeta>,
@@ -231,6 +231,10 @@ fn relocations_by_section(
for (address, reloc) in obj_section.relocations() {
let symbol = match reloc.target() {
RelocationTarget::Symbol(idx) => {
if idx.0 == u32::MAX as usize {
// ???
continue;
}
let Ok(symbol) = obj_file.symbol_by_index(idx) else {
log::warn!(
"Failed to locate relocation {:#x} target symbol {}",
@@ -243,60 +247,7 @@ fn relocations_by_section(
}
_ => bail!("Unhandled relocation target: {:?}", reloc.target()),
};
let kind = match reloc.flags() {
RelocationFlags::Elf { r_type } => match arch {
#[cfg(feature = "ppc")]
ObjArchitecture::PowerPc => match r_type {
elf::R_PPC_ADDR32 | elf::R_PPC_UADDR32 => ObjRelocKind::Absolute,
elf::R_PPC_ADDR16_LO => ObjRelocKind::PpcAddr16Lo,
elf::R_PPC_ADDR16_HI => ObjRelocKind::PpcAddr16Hi,
elf::R_PPC_ADDR16_HA => ObjRelocKind::PpcAddr16Ha,
elf::R_PPC_REL24 => ObjRelocKind::PpcRel24,
elf::R_PPC_REL14 => ObjRelocKind::PpcRel14,
elf::R_PPC_EMB_SDA21 => ObjRelocKind::PpcEmbSda21,
_ => bail!("Unhandled ELF PPC relocation type: {r_type}"),
},
#[cfg(feature = "mips")]
ObjArchitecture::Mips => match r_type {
elf::R_MIPS_32 => ObjRelocKind::Absolute,
elf::R_MIPS_26 => ObjRelocKind::Mips26,
elf::R_MIPS_HI16 => ObjRelocKind::MipsHi16,
elf::R_MIPS_LO16 => ObjRelocKind::MipsLo16,
elf::R_MIPS_GOT16 => ObjRelocKind::MipsGot16,
elf::R_MIPS_CALL16 => ObjRelocKind::MipsCall16,
elf::R_MIPS_GPREL16 => ObjRelocKind::MipsGpRel16,
elf::R_MIPS_GPREL32 => ObjRelocKind::MipsGpRel32,
_ => bail!("Unhandled ELF MIPS relocation type: {r_type}"),
},
#[cfg(feature = "x86")]
ObjArchitecture::X86_32 => match r_type {
elf::R_386_32 => ObjRelocKind::Absolute,
elf::R_386_PC32 => ObjRelocKind::X86PcRel32,
_ => bail!("Unhandled ELF x86_32 relocation type: {r_type}"),
},
#[cfg(feature = "x86")]
ObjArchitecture::X86_64 => match r_type {
elf::R_X86_64_32 => ObjRelocKind::Absolute,
elf::R_X86_64_PC32 => ObjRelocKind::X86PcRel32,
_ => bail!("Unhandled ELF x86_64 relocation type: {r_type}"),
},
},
RelocationFlags::Coff { typ } => match arch {
#[cfg(feature = "ppc")]
ObjArchitecture::PowerPc => bail!("Unhandled PE/COFF PPC relocation type: {typ}"),
#[cfg(feature = "mips")]
ObjArchitecture::Mips => bail!("Unhandled PE/COFF MIPS relocation type: {typ}"),
#[cfg(feature = "x86")]
ObjArchitecture::X86_32 => match typ {
pe::IMAGE_REL_I386_DIR32 => ObjRelocKind::Absolute,
pe::IMAGE_REL_I386_REL32 => ObjRelocKind::X86PcRel32,
_ => bail!("Unhandled PE/COFF x86 relocation type: {typ}"),
},
#[cfg(feature = "x86")]
ObjArchitecture::X86_64 => bail!("Unhandled PE/COFF x86_64 relocation type: {typ}"),
},
flags => bail!("Unhandled relocation flags: {:?}", flags),
};
let flags = reloc.flags(); // TODO validate reloc here?
let target_section = match symbol.section() {
SymbolSection::Common => Some(".comm".to_string()),
SymbolSection::Section(idx) => {
@@ -305,40 +256,22 @@ fn relocations_by_section(
_ => None,
};
let addend = if reloc.has_implicit_addend() {
let data = section.data[address as usize..address as usize + 4].try_into()?;
let addend = obj_file.endianness().read_u32_bytes(data);
match kind {
ObjRelocKind::Absolute => addend as i64,
#[cfg(feature = "mips")]
ObjRelocKind::MipsHi16 => ((addend & 0x0000FFFF) << 16) as i32 as i64,
#[cfg(feature = "mips")]
ObjRelocKind::MipsLo16
| ObjRelocKind::MipsGot16
| ObjRelocKind::MipsCall16
| ObjRelocKind::MipsGpRel16 => (addend & 0x0000FFFF) as i16 as i64,
#[cfg(feature = "mips")]
ObjRelocKind::MipsGpRel32 => addend as i32 as i64,
#[cfg(feature = "mips")]
ObjRelocKind::Mips26 => ((addend & 0x03FFFFFF) << 2) as i64,
#[cfg(feature = "x86")]
ObjRelocKind::X86PcRel32 => addend as i32 as i64,
_ => bail!("Unsupported implicit relocation {kind:?}"),
}
arch.implcit_addend(section, address, &reloc)?
} else {
reloc.addend()
};
// println!("Reloc: {reloc:?}, symbol: {symbol:?}, addend: {addend:#X}");
let target = match symbol.kind() {
SymbolKind::Text | SymbolKind::Data | SymbolKind::Label | SymbolKind::Unknown => {
to_obj_symbol(obj_file, &symbol, addend, split_meta)
to_obj_symbol(arch, obj_file, &symbol, addend, split_meta)
}
SymbolKind::Section => {
ensure!(addend >= 0, "Negative addend in reloc: {addend}");
find_section_symbol(obj_file, &symbol, addend as u64, split_meta)
find_section_symbol(arch, obj_file, &symbol, addend as u64, split_meta)
}
kind => Err(anyhow!("Unhandled relocation symbol type {kind:?}")),
}?;
relocations.push(ObjReloc { kind, address, target, target_section });
relocations.push(ObjReloc { flags, address, target, target_section });
}
Ok(relocations)
}
@@ -408,34 +341,25 @@ pub fn read(obj_path: &Path) -> Result<ObjInfo> {
(unsafe { memmap2::Mmap::map(&file) }?, timestamp)
};
let obj_file = File::parse(&*data)?;
let architecture = match obj_file.architecture() {
#[cfg(feature = "ppc")]
Architecture::PowerPc => ObjArchitecture::PowerPc,
#[cfg(feature = "mips")]
Architecture::Mips => ObjArchitecture::Mips,
#[cfg(feature = "x86")]
Architecture::I386 => ObjArchitecture::X86_32,
#[cfg(feature = "x86")]
Architecture::X86_64 => ObjArchitecture::X86_64,
_ => bail!("Unsupported architecture: {:?}", obj_file.architecture()),
};
let arch = new_arch(&obj_file)?;
let split_meta = split_meta(&obj_file)?;
let mut result = ObjInfo {
architecture,
let mut sections = filter_sections(&obj_file, split_meta.as_ref())?;
for section in &mut sections {
section.symbols =
symbols_by_section(arch.as_ref(), &obj_file, section, split_meta.as_ref())?;
section.relocations =
relocations_by_section(arch.as_ref(), &obj_file, section, split_meta.as_ref())?;
}
let common = common_symbols(arch.as_ref(), &obj_file, split_meta.as_ref())?;
Ok(ObjInfo {
arch,
path: obj_path.to_owned(),
timestamp,
sections: filter_sections(&obj_file, split_meta.as_ref())?,
common: common_symbols(&obj_file, split_meta.as_ref())?,
sections,
common,
line_info: line_info(&obj_file)?,
split_meta: None,
};
for section in &mut result.sections {
section.symbols = symbols_by_section(&obj_file, section, split_meta.as_ref())?;
section.relocations =
relocations_by_section(architecture, &obj_file, section, split_meta.as_ref())?;
}
result.split_meta = split_meta;
Ok(result)
split_meta,
})
}
pub fn has_function(obj_path: &Path, symbol_name: &str) -> Result<bool> {