comm-central/third_party/rust/object/src/write/elf/object.rs

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use alloc::vec::Vec;
use crate::write::elf::writer::*;
use crate::write::string::StringId;
use crate::write::*;
use crate::{elf, pod};
#[derive(Clone, Copy)]
struct ComdatOffsets {
offset: usize,
str_id: StringId,
}
#[derive(Clone, Copy)]
struct SectionOffsets {
index: SectionIndex,
offset: usize,
str_id: StringId,
reloc_offset: usize,
reloc_str_id: Option<StringId>,
}
#[derive(Default, Clone, Copy)]
struct SymbolOffsets {
index: SymbolIndex,
str_id: Option<StringId>,
}
// Public methods.
impl<'a> Object<'a> {
/// Add a property with a u32 value to the ELF ".note.gnu.property" section.
///
/// Requires `feature = "elf"`.
pub fn add_elf_gnu_property_u32(&mut self, property: u32, value: u32) {
if self.format != BinaryFormat::Elf {
return;
}
let align = if self.elf_is_64() { 8 } else { 4 };
let mut data = Vec::with_capacity(32);
let n_name = b"GNU\0";
data.extend_from_slice(pod::bytes_of(&elf::NoteHeader32 {
n_namesz: U32::new(self.endian, n_name.len() as u32),
n_descsz: U32::new(self.endian, util::align(3 * 4, align) as u32),
n_type: U32::new(self.endian, elf::NT_GNU_PROPERTY_TYPE_0),
}));
data.extend_from_slice(n_name);
// This happens to already be aligned correctly.
debug_assert_eq!(util::align(data.len(), align), data.len());
data.extend_from_slice(pod::bytes_of(&U32::new(self.endian, property)));
// Value size
data.extend_from_slice(pod::bytes_of(&U32::new(self.endian, 4)));
data.extend_from_slice(pod::bytes_of(&U32::new(self.endian, value)));
util::write_align(&mut data, align);
let section = self.section_id(StandardSection::GnuProperty);
self.append_section_data(section, &data, align as u64);
}
}
// Private methods.
impl<'a> Object<'a> {
pub(crate) fn elf_section_info(
&self,
section: StandardSection,
) -> (&'static [u8], &'static [u8], SectionKind, SectionFlags) {
match section {
StandardSection::Text => (&[], &b".text"[..], SectionKind::Text, SectionFlags::None),
StandardSection::Data => (&[], &b".data"[..], SectionKind::Data, SectionFlags::None),
StandardSection::ReadOnlyData | StandardSection::ReadOnlyString => (
&[],
&b".rodata"[..],
SectionKind::ReadOnlyData,
SectionFlags::None,
),
StandardSection::ReadOnlyDataWithRel => (
&[],
b".data.rel.ro",
SectionKind::ReadOnlyDataWithRel,
SectionFlags::None,
),
StandardSection::UninitializedData => (
&[],
&b".bss"[..],
SectionKind::UninitializedData,
SectionFlags::None,
),
StandardSection::Tls => (&[], &b".tdata"[..], SectionKind::Tls, SectionFlags::None),
StandardSection::UninitializedTls => (
&[],
&b".tbss"[..],
SectionKind::UninitializedTls,
SectionFlags::None,
),
StandardSection::TlsVariables => {
// Unsupported section.
(&[], &[], SectionKind::TlsVariables, SectionFlags::None)
}
StandardSection::Common => {
// Unsupported section.
(&[], &[], SectionKind::Common, SectionFlags::None)
}
StandardSection::GnuProperty => (
&[],
&b".note.gnu.property"[..],
SectionKind::Note,
SectionFlags::Elf {
sh_flags: u64::from(elf::SHF_ALLOC),
},
),
}
}
pub(crate) fn elf_subsection_name(&self, section: &[u8], value: &[u8]) -> Vec<u8> {
let mut name = section.to_vec();
name.push(b'.');
name.extend_from_slice(value);
name
}
fn elf_has_relocation_addend(&self) -> Result<bool> {
Ok(match self.architecture {
Architecture::Aarch64 => true,
Architecture::Aarch64_Ilp32 => true,
Architecture::Arm => false,
Architecture::Avr => true,
Architecture::Bpf => false,
Architecture::Csky => true,
Architecture::I386 => false,
Architecture::X86_64 => true,
Architecture::X86_64_X32 => true,
Architecture::Hexagon => true,
Architecture::LoongArch64 => true,
Architecture::Mips => false,
Architecture::Mips64 => true,
Architecture::Msp430 => true,
Architecture::PowerPc => true,
Architecture::PowerPc64 => true,
Architecture::Riscv64 => true,
Architecture::Riscv32 => true,
Architecture::S390x => true,
Architecture::Sbf => false,
Architecture::Sharc => true,
Architecture::Sparc => true,
Architecture::Sparc32Plus => true,
Architecture::Sparc64 => true,
Architecture::Xtensa => true,
_ => {
return Err(Error(format!(
"unimplemented architecture {:?}",
self.architecture
)));
}
})
}
pub(crate) fn elf_translate_relocation(&mut self, reloc: &mut Relocation) -> Result<()> {
let (kind, encoding, size) = if let RelocationFlags::Generic {
kind,
encoding,
size,
} = reloc.flags
{
(kind, encoding, size)
} else {
return Ok(());
};
let r_type = match self.architecture {
Architecture::Aarch64 => match (kind, encoding, size) {
(RelocationKind::Absolute, RelocationEncoding::Generic, 64) => elf::R_AARCH64_ABS64,
(RelocationKind::Absolute, RelocationEncoding::Generic, 32) => elf::R_AARCH64_ABS32,
(RelocationKind::Absolute, RelocationEncoding::Generic, 16) => elf::R_AARCH64_ABS16,
(RelocationKind::Relative, RelocationEncoding::Generic, 64) => {
elf::R_AARCH64_PREL64
}
(RelocationKind::Relative, RelocationEncoding::Generic, 32) => {
elf::R_AARCH64_PREL32
}
(RelocationKind::Relative, RelocationEncoding::Generic, 16) => {
elf::R_AARCH64_PREL16
}
(RelocationKind::Relative, RelocationEncoding::AArch64Call, 26)
| (RelocationKind::PltRelative, RelocationEncoding::AArch64Call, 26) => {
elf::R_AARCH64_CALL26
}
_ => {
return Err(Error(format!("unimplemented relocation {:?}", reloc)));
}
},
Architecture::Aarch64_Ilp32 => match (kind, encoding, size) {
(RelocationKind::Absolute, RelocationEncoding::Generic, 32) => {
elf::R_AARCH64_P32_ABS32
}
_ => {
return Err(Error(format!("unimplemented relocation {:?}", reloc)));
}
},
Architecture::Arm => match (kind, encoding, size) {
(RelocationKind::Absolute, _, 32) => elf::R_ARM_ABS32,
_ => {
return Err(Error(format!("unimplemented relocation {:?}", reloc)));
}
},
Architecture::Avr => match (kind, encoding, size) {
(RelocationKind::Absolute, _, 32) => elf::R_AVR_32,
(RelocationKind::Absolute, _, 16) => elf::R_AVR_16,
_ => {
return Err(Error(format!("unimplemented relocation {:?}", reloc)));
}
},
Architecture::Bpf => match (kind, encoding, size) {
(RelocationKind::Absolute, _, 64) => elf::R_BPF_64_64,
(RelocationKind::Absolute, _, 32) => elf::R_BPF_64_32,
_ => {
return Err(Error(format!("unimplemented relocation {:?}", reloc)));
}
},
Architecture::Csky => match (kind, encoding, size) {
(RelocationKind::Absolute, _, 32) => elf::R_CKCORE_ADDR32,
(RelocationKind::Relative, RelocationEncoding::Generic, 32) => {
elf::R_CKCORE_PCREL32
}
_ => {
return Err(Error(format!("unimplemented relocation {:?}", reloc)));
}
},
Architecture::I386 => match (kind, size) {
(RelocationKind::Absolute, 32) => elf::R_386_32,
(RelocationKind::Relative, 32) => elf::R_386_PC32,
(RelocationKind::Got, 32) => elf::R_386_GOT32,
(RelocationKind::PltRelative, 32) => elf::R_386_PLT32,
(RelocationKind::GotBaseOffset, 32) => elf::R_386_GOTOFF,
(RelocationKind::GotBaseRelative, 32) => elf::R_386_GOTPC,
(RelocationKind::Absolute, 16) => elf::R_386_16,
(RelocationKind::Relative, 16) => elf::R_386_PC16,
(RelocationKind::Absolute, 8) => elf::R_386_8,
(RelocationKind::Relative, 8) => elf::R_386_PC8,
_ => {
return Err(Error(format!("unimplemented relocation {:?}", reloc)));
}
},
Architecture::X86_64 | Architecture::X86_64_X32 => match (kind, encoding, size) {
(RelocationKind::Absolute, RelocationEncoding::Generic, 64) => elf::R_X86_64_64,
(RelocationKind::Relative, RelocationEncoding::X86Branch, 32) => {
elf::R_X86_64_PLT32
}
(RelocationKind::Relative, _, 32) => elf::R_X86_64_PC32,
(RelocationKind::Got, _, 32) => elf::R_X86_64_GOT32,
(RelocationKind::PltRelative, _, 32) => elf::R_X86_64_PLT32,
(RelocationKind::GotRelative, _, 32) => elf::R_X86_64_GOTPCREL,
(RelocationKind::Absolute, RelocationEncoding::Generic, 32) => elf::R_X86_64_32,
(RelocationKind::Absolute, RelocationEncoding::X86Signed, 32) => elf::R_X86_64_32S,
(RelocationKind::Absolute, _, 16) => elf::R_X86_64_16,
(RelocationKind::Relative, _, 16) => elf::R_X86_64_PC16,
(RelocationKind::Absolute, _, 8) => elf::R_X86_64_8,
(RelocationKind::Relative, _, 8) => elf::R_X86_64_PC8,
_ => {
return Err(Error(format!("unimplemented relocation {:?}", reloc)));
}
},
Architecture::Hexagon => match (kind, encoding, size) {
(RelocationKind::Absolute, _, 32) => elf::R_HEX_32,
_ => {
return Err(Error(format!("unimplemented relocation {:?}", reloc)));
}
},
Architecture::LoongArch64 => match (kind, encoding, size) {
(RelocationKind::Absolute, _, 32) => elf::R_LARCH_32,
(RelocationKind::Absolute, _, 64) => elf::R_LARCH_64,
(RelocationKind::Relative, _, 32) => elf::R_LARCH_32_PCREL,
(RelocationKind::Relative, _, 64) => elf::R_LARCH_64_PCREL,
(RelocationKind::Relative, RelocationEncoding::LoongArchBranch, 16)
| (RelocationKind::PltRelative, RelocationEncoding::LoongArchBranch, 16) => {
elf::R_LARCH_B16
}
(RelocationKind::Relative, RelocationEncoding::LoongArchBranch, 21)
| (RelocationKind::PltRelative, RelocationEncoding::LoongArchBranch, 21) => {
elf::R_LARCH_B21
}
(RelocationKind::Relative, RelocationEncoding::LoongArchBranch, 26)
| (RelocationKind::PltRelative, RelocationEncoding::LoongArchBranch, 26) => {
elf::R_LARCH_B26
}
_ => {
return Err(Error(format!("unimplemented relocation {:?}", reloc)));
}
},
Architecture::Mips | Architecture::Mips64 => match (kind, encoding, size) {
(RelocationKind::Absolute, _, 16) => elf::R_MIPS_16,
(RelocationKind::Absolute, _, 32) => elf::R_MIPS_32,
(RelocationKind::Absolute, _, 64) => elf::R_MIPS_64,
_ => {
return Err(Error(format!("unimplemented relocation {:?}", reloc)));
}
},
Architecture::Msp430 => match (kind, encoding, size) {
(RelocationKind::Absolute, _, 32) => elf::R_MSP430_32,
(RelocationKind::Absolute, _, 16) => elf::R_MSP430_16_BYTE,
_ => {
return Err(Error(format!("unimplemented relocation {:?}", reloc)));
}
},
Architecture::PowerPc => match (kind, encoding, size) {
(RelocationKind::Absolute, _, 32) => elf::R_PPC_ADDR32,
_ => {
return Err(Error(format!("unimplemented relocation {:?}", reloc)));
}
},
Architecture::PowerPc64 => match (kind, encoding, size) {
(RelocationKind::Absolute, _, 32) => elf::R_PPC64_ADDR32,
(RelocationKind::Absolute, _, 64) => elf::R_PPC64_ADDR64,
_ => {
return Err(Error(format!("unimplemented relocation {:?}", reloc)));
}
},
Architecture::Riscv32 | Architecture::Riscv64 => match (kind, encoding, size) {
(RelocationKind::Absolute, _, 32) => elf::R_RISCV_32,
(RelocationKind::Absolute, _, 64) => elf::R_RISCV_64,
(RelocationKind::Relative, RelocationEncoding::Generic, 32) => {
elf::R_RISCV_32_PCREL
}
_ => {
return Err(Error(format!("unimplemented relocation {:?}", reloc)));
}
},
Architecture::S390x => match (kind, encoding, size) {
(RelocationKind::Absolute, RelocationEncoding::Generic, 8) => elf::R_390_8,
(RelocationKind::Absolute, RelocationEncoding::Generic, 16) => elf::R_390_16,
(RelocationKind::Absolute, RelocationEncoding::Generic, 32) => elf::R_390_32,
(RelocationKind::Absolute, RelocationEncoding::Generic, 64) => elf::R_390_64,
(RelocationKind::Relative, RelocationEncoding::Generic, 16) => elf::R_390_PC16,
(RelocationKind::Relative, RelocationEncoding::Generic, 32) => elf::R_390_PC32,
(RelocationKind::Relative, RelocationEncoding::Generic, 64) => elf::R_390_PC64,
(RelocationKind::Relative, RelocationEncoding::S390xDbl, 16) => elf::R_390_PC16DBL,
(RelocationKind::Relative, RelocationEncoding::S390xDbl, 32) => elf::R_390_PC32DBL,
(RelocationKind::PltRelative, RelocationEncoding::S390xDbl, 16) => {
elf::R_390_PLT16DBL
}
(RelocationKind::PltRelative, RelocationEncoding::S390xDbl, 32) => {
elf::R_390_PLT32DBL
}
(RelocationKind::Got, RelocationEncoding::Generic, 16) => elf::R_390_GOT16,
(RelocationKind::Got, RelocationEncoding::Generic, 32) => elf::R_390_GOT32,
(RelocationKind::Got, RelocationEncoding::Generic, 64) => elf::R_390_GOT64,
(RelocationKind::GotRelative, RelocationEncoding::S390xDbl, 32) => {
elf::R_390_GOTENT
}
(RelocationKind::GotBaseOffset, RelocationEncoding::Generic, 16) => {
elf::R_390_GOTOFF16
}
(RelocationKind::GotBaseOffset, RelocationEncoding::Generic, 32) => {
elf::R_390_GOTOFF32
}
(RelocationKind::GotBaseOffset, RelocationEncoding::Generic, 64) => {
elf::R_390_GOTOFF64
}
(RelocationKind::GotBaseRelative, RelocationEncoding::Generic, 64) => {
elf::R_390_GOTPC
}
(RelocationKind::GotBaseRelative, RelocationEncoding::S390xDbl, 32) => {
elf::R_390_GOTPCDBL
}
_ => {
return Err(Error(format!("unimplemented relocation {:?}", reloc)));
}
},
Architecture::Sbf => match (kind, encoding, size) {
(RelocationKind::Absolute, _, 64) => elf::R_SBF_64_64,
(RelocationKind::Absolute, _, 32) => elf::R_SBF_64_32,
_ => {
return Err(Error(format!("unimplemented relocation {:?}", reloc)));
}
},
Architecture::Sharc => match (kind, encoding, size) {
(RelocationKind::Absolute, RelocationEncoding::SharcTypeA, 32) => {
elf::R_SHARC_ADDR32_V3
}
(RelocationKind::Absolute, RelocationEncoding::Generic, 32) => {
elf::R_SHARC_ADDR_VAR_V3
}
(RelocationKind::Relative, RelocationEncoding::SharcTypeA, 24) => {
elf::R_SHARC_PCRLONG_V3
}
(RelocationKind::Relative, RelocationEncoding::SharcTypeA, 6) => {
elf::R_SHARC_PCRSHORT_V3
}
(RelocationKind::Relative, RelocationEncoding::SharcTypeB, 6) => {
elf::R_SHARC_PCRSHORT_V3
}
(RelocationKind::Absolute, RelocationEncoding::Generic, 16) => {
elf::R_SHARC_ADDR_VAR16_V3
}
(RelocationKind::Absolute, RelocationEncoding::SharcTypeA, 16) => {
elf::R_SHARC_DATA16_V3
}
(RelocationKind::Absolute, RelocationEncoding::SharcTypeB, 16) => {
elf::R_SHARC_DATA16_VISA_V3
}
(RelocationKind::Absolute, RelocationEncoding::SharcTypeA, 24) => {
elf::R_SHARC_ADDR24_V3
}
(RelocationKind::Absolute, RelocationEncoding::SharcTypeA, 6) => {
elf::R_SHARC_DATA6_V3
}
(RelocationKind::Absolute, RelocationEncoding::SharcTypeB, 6) => {
elf::R_SHARC_DATA6_VISA_V3
}
(RelocationKind::Absolute, RelocationEncoding::SharcTypeB, 7) => {
elf::R_SHARC_DATA7_VISA_V3
}
_ => {
return Err(Error(format!("unimplemented relocation {:?}", reloc)));
}
},
Architecture::Sparc | Architecture::Sparc32Plus => match (kind, encoding, size) {
// TODO: use R_SPARC_32 if aligned.
(RelocationKind::Absolute, _, 32) => elf::R_SPARC_UA32,
_ => {
return Err(Error(format!("unimplemented relocation {:?}", reloc)));
}
},
Architecture::Sparc64 => match (kind, encoding, size) {
// TODO: use R_SPARC_32/R_SPARC_64 if aligned.
(RelocationKind::Absolute, _, 32) => elf::R_SPARC_UA32,
(RelocationKind::Absolute, _, 64) => elf::R_SPARC_UA64,
_ => {
return Err(Error(format!("unimplemented relocation {:?}", reloc)));
}
},
Architecture::Xtensa => match (kind, encoding, size) {
(RelocationKind::Absolute, _, 32) => elf::R_XTENSA_32,
(RelocationKind::Relative, RelocationEncoding::Generic, 32) => {
elf::R_XTENSA_32_PCREL
}
_ => {
return Err(Error(format!("unimplemented relocation {:?}", reloc)));
}
},
_ => {
return Err(Error(format!("unimplemented relocation {:?}", reloc)));
}
};
reloc.flags = RelocationFlags::Elf { r_type };
Ok(())
}
pub(crate) fn elf_adjust_addend(&mut self, _relocation: &mut Relocation) -> Result<bool> {
// Determine whether the addend is stored in the relocation or the data.
let implicit = !self.elf_has_relocation_addend()?;
Ok(implicit)
}
pub(crate) fn elf_relocation_size(&self, reloc: &Relocation) -> Result<u8> {
let r_type = if let RelocationFlags::Elf { r_type } = reloc.flags {
r_type
} else {
return Err(Error("invalid relocation flags".into()));
};
// This only needs to support architectures that use implicit addends.
let size = match self.architecture {
Architecture::Arm => match r_type {
elf::R_ARM_ABS16 => Some(16),
elf::R_ARM_ABS32 | elf::R_ARM_REL32 => Some(32),
_ => None,
},
Architecture::Bpf => match r_type {
elf::R_BPF_64_32 => Some(32),
elf::R_BPF_64_64 => Some(64),
_ => None,
},
Architecture::I386 => match r_type {
elf::R_386_8 | elf::R_386_PC8 => Some(8),
elf::R_386_16 | elf::R_386_PC16 => Some(16),
elf::R_386_32
| elf::R_386_PC32
| elf::R_386_GOT32
| elf::R_386_PLT32
| elf::R_386_GOTOFF
| elf::R_386_GOTPC => Some(32),
_ => None,
},
Architecture::Mips => match r_type {
elf::R_MIPS_16 => Some(16),
elf::R_MIPS_32 => Some(32),
elf::R_MIPS_64 => Some(64),
_ => None,
},
Architecture::Sbf => match r_type {
elf::R_SBF_64_32 => Some(32),
elf::R_SBF_64_64 => Some(64),
_ => None,
},
_ => {
return Err(Error(format!(
"unimplemented architecture {:?}",
self.architecture
)));
}
};
size.ok_or_else(|| Error(format!("unsupported relocation for size {:?}", reloc)))
}
pub(crate) fn elf_is_64(&self) -> bool {
match self.architecture.address_size().unwrap() {
AddressSize::U8 | AddressSize::U16 | AddressSize::U32 => false,
AddressSize::U64 => true,
}
}
pub(crate) fn elf_write(&self, buffer: &mut dyn WritableBuffer) -> Result<()> {
// Create reloc section header names so we can reference them.
let is_rela = self.elf_has_relocation_addend()?;
let reloc_names: Vec<_> = self
.sections
.iter()
.map(|section| {
let mut reloc_name = Vec::with_capacity(
if is_rela { ".rela".len() } else { ".rel".len() } + section.name.len(),
);
if !section.relocations.is_empty() {
reloc_name.extend_from_slice(if is_rela {
&b".rela"[..]
} else {
&b".rel"[..]
});
reloc_name.extend_from_slice(&section.name);
}
reloc_name
})
.collect();
// Start calculating offsets of everything.
let mut writer = Writer::new(self.endian, self.elf_is_64(), buffer);
writer.reserve_file_header();
// Calculate size of section data.
let mut comdat_offsets = Vec::with_capacity(self.comdats.len());
for comdat in &self.comdats {
if comdat.kind != ComdatKind::Any {
return Err(Error(format!(
"unsupported COMDAT symbol `{}` kind {:?}",
self.symbols[comdat.symbol.0].name().unwrap_or(""),
comdat.kind
)));
}
writer.reserve_section_index();
let offset = writer.reserve_comdat(comdat.sections.len());
let str_id = writer.add_section_name(b".group");
comdat_offsets.push(ComdatOffsets { offset, str_id });
}
let mut section_offsets = Vec::with_capacity(self.sections.len());
for (section, reloc_name) in self.sections.iter().zip(reloc_names.iter()) {
let index = writer.reserve_section_index();
let offset = writer.reserve(section.data.len(), section.align as usize);
let str_id = writer.add_section_name(&section.name);
let mut reloc_str_id = None;
if !section.relocations.is_empty() {
writer.reserve_section_index();
reloc_str_id = Some(writer.add_section_name(reloc_name));
}
section_offsets.push(SectionOffsets {
index,
offset,
str_id,
// Relocation data is reserved later.
reloc_offset: 0,
reloc_str_id,
});
}
// Calculate index of symbols and add symbol strings to strtab.
let mut symbol_offsets = vec![SymbolOffsets::default(); self.symbols.len()];
writer.reserve_null_symbol_index();
// Local symbols must come before global.
for (index, symbol) in self.symbols.iter().enumerate() {
if symbol.is_local() {
let section_index = symbol.section.id().map(|s| section_offsets[s.0].index);
symbol_offsets[index].index = writer.reserve_symbol_index(section_index);
}
}
let symtab_num_local = writer.symbol_count();
for (index, symbol) in self.symbols.iter().enumerate() {
if !symbol.is_local() {
let section_index = symbol.section.id().map(|s| section_offsets[s.0].index);
symbol_offsets[index].index = writer.reserve_symbol_index(section_index);
}
}
for (index, symbol) in self.symbols.iter().enumerate() {
if symbol.kind != SymbolKind::Section && !symbol.name.is_empty() {
symbol_offsets[index].str_id = Some(writer.add_string(&symbol.name));
}
}
// Calculate size of symbols.
writer.reserve_symtab_section_index();
writer.reserve_symtab();
if writer.symtab_shndx_needed() {
writer.reserve_symtab_shndx_section_index();
}
writer.reserve_symtab_shndx();
writer.reserve_strtab_section_index();
writer.reserve_strtab();
// Calculate size of relocations.
for (index, section) in self.sections.iter().enumerate() {
let count = section.relocations.len();
if count != 0 {
section_offsets[index].reloc_offset = writer.reserve_relocations(count, is_rela);
}
}
// Calculate size of section headers.
writer.reserve_shstrtab_section_index();
writer.reserve_shstrtab();
writer.reserve_section_headers();
// Start writing.
let e_type = elf::ET_REL;
let e_machine = match (self.architecture, self.sub_architecture) {
(Architecture::Aarch64, None) => elf::EM_AARCH64,
(Architecture::Aarch64_Ilp32, None) => elf::EM_AARCH64,
(Architecture::Arm, None) => elf::EM_ARM,
(Architecture::Avr, None) => elf::EM_AVR,
(Architecture::Bpf, None) => elf::EM_BPF,
(Architecture::Csky, None) => elf::EM_CSKY,
(Architecture::I386, None) => elf::EM_386,
(Architecture::X86_64, None) => elf::EM_X86_64,
(Architecture::X86_64_X32, None) => elf::EM_X86_64,
(Architecture::Hexagon, None) => elf::EM_HEXAGON,
(Architecture::LoongArch64, None) => elf::EM_LOONGARCH,
(Architecture::Mips, None) => elf::EM_MIPS,
(Architecture::Mips64, None) => elf::EM_MIPS,
(Architecture::Msp430, None) => elf::EM_MSP430,
(Architecture::PowerPc, None) => elf::EM_PPC,
(Architecture::PowerPc64, None) => elf::EM_PPC64,
(Architecture::Riscv32, None) => elf::EM_RISCV,
(Architecture::Riscv64, None) => elf::EM_RISCV,
(Architecture::S390x, None) => elf::EM_S390,
(Architecture::Sbf, None) => elf::EM_SBF,
(Architecture::Sharc, None) => elf::EM_SHARC,
(Architecture::Sparc, None) => elf::EM_SPARC,
(Architecture::Sparc32Plus, None) => elf::EM_SPARC32PLUS,
(Architecture::Sparc64, None) => elf::EM_SPARCV9,
(Architecture::Xtensa, None) => elf::EM_XTENSA,
_ => {
return Err(Error(format!(
"unimplemented architecture {:?} with sub-architecture {:?}",
self.architecture, self.sub_architecture
)));
}
};
let (os_abi, abi_version, e_flags) = if let FileFlags::Elf {
os_abi,
abi_version,
e_flags,
} = self.flags
{
(os_abi, abi_version, e_flags)
} else {
(elf::ELFOSABI_NONE, 0, 0)
};
writer.write_file_header(&FileHeader {
os_abi,
abi_version,
e_type,
e_machine,
e_entry: 0,
e_flags,
})?;
// Write section data.
for comdat in &self.comdats {
writer.write_comdat_header();
for section in &comdat.sections {
writer.write_comdat_entry(section_offsets[section.0].index);
}
}
for (index, section) in self.sections.iter().enumerate() {
writer.write_align(section.align as usize);
debug_assert_eq!(section_offsets[index].offset, writer.len());
writer.write(&section.data);
}
// Write symbols.
writer.write_null_symbol();
let mut write_symbol = |index: usize, symbol: &Symbol| -> Result<()> {
let st_info = if let SymbolFlags::Elf { st_info, .. } = symbol.flags {
st_info
} else {
let st_type = match symbol.kind {
SymbolKind::Text => {
if symbol.is_undefined() {
elf::STT_NOTYPE
} else {
elf::STT_FUNC
}
}
SymbolKind::Data => {
if symbol.is_undefined() {
elf::STT_NOTYPE
} else if symbol.is_common() {
elf::STT_COMMON
} else {
elf::STT_OBJECT
}
}
SymbolKind::Section => elf::STT_SECTION,
SymbolKind::File => elf::STT_FILE,
SymbolKind::Tls => elf::STT_TLS,
SymbolKind::Label => elf::STT_NOTYPE,
SymbolKind::Unknown => {
if symbol.is_undefined() {
elf::STT_NOTYPE
} else {
return Err(Error(format!(
"unimplemented symbol `{}` kind {:?}",
symbol.name().unwrap_or(""),
symbol.kind
)));
}
}
};
let st_bind = if symbol.weak {
elf::STB_WEAK
} else if symbol.is_undefined() {
elf::STB_GLOBAL
} else if symbol.is_local() {
elf::STB_LOCAL
} else {
elf::STB_GLOBAL
};
(st_bind << 4) + st_type
};
let st_other = if let SymbolFlags::Elf { st_other, .. } = symbol.flags {
st_other
} else if symbol.scope == SymbolScope::Linkage {
elf::STV_HIDDEN
} else {
elf::STV_DEFAULT
};
let (st_shndx, section) = match symbol.section {
SymbolSection::None => {
debug_assert_eq!(symbol.kind, SymbolKind::File);
(elf::SHN_ABS, None)
}
SymbolSection::Undefined => (elf::SHN_UNDEF, None),
SymbolSection::Absolute => (elf::SHN_ABS, None),
SymbolSection::Common => (elf::SHN_COMMON, None),
SymbolSection::Section(id) => (0, Some(section_offsets[id.0].index)),
};
writer.write_symbol(&Sym {
name: symbol_offsets[index].str_id,
section,
st_info,
st_other,
st_shndx,
st_value: symbol.value,
st_size: symbol.size,
});
Ok(())
};
for (index, symbol) in self.symbols.iter().enumerate() {
if symbol.is_local() {
write_symbol(index, symbol)?;
}
}
for (index, symbol) in self.symbols.iter().enumerate() {
if !symbol.is_local() {
write_symbol(index, symbol)?;
}
}
writer.write_symtab_shndx();
writer.write_strtab();
// Write relocations.
for (index, section) in self.sections.iter().enumerate() {
if !section.relocations.is_empty() {
writer.write_align_relocation();
debug_assert_eq!(section_offsets[index].reloc_offset, writer.len());
for reloc in &section.relocations {
let r_type = if let RelocationFlags::Elf { r_type } = reloc.flags {
r_type
} else {
return Err(Error("invalid relocation flags".into()));
};
let r_sym = symbol_offsets[reloc.symbol.0].index.0;
writer.write_relocation(
is_rela,
&Rel {
r_offset: reloc.offset,
r_sym,
r_type,
r_addend: reloc.addend,
},
);
}
}
}
writer.write_shstrtab();
// Write section headers.
writer.write_null_section_header();
let symtab_index = writer.symtab_index();
for (comdat, comdat_offset) in self.comdats.iter().zip(comdat_offsets.iter()) {
writer.write_comdat_section_header(
comdat_offset.str_id,
symtab_index,
symbol_offsets[comdat.symbol.0].index,
comdat_offset.offset,
comdat.sections.len(),
);
}
for (index, section) in self.sections.iter().enumerate() {
let sh_type = match section.kind {
SectionKind::UninitializedData | SectionKind::UninitializedTls => elf::SHT_NOBITS,
SectionKind::Note => elf::SHT_NOTE,
SectionKind::Elf(sh_type) => sh_type,
_ => elf::SHT_PROGBITS,
};
let sh_flags = if let SectionFlags::Elf { sh_flags } = section.flags {
sh_flags
} else {
match section.kind {
SectionKind::Text => elf::SHF_ALLOC | elf::SHF_EXECINSTR,
SectionKind::Data | SectionKind::ReadOnlyDataWithRel => {
elf::SHF_ALLOC | elf::SHF_WRITE
}
SectionKind::Tls => elf::SHF_ALLOC | elf::SHF_WRITE | elf::SHF_TLS,
SectionKind::UninitializedData => elf::SHF_ALLOC | elf::SHF_WRITE,
SectionKind::UninitializedTls => elf::SHF_ALLOC | elf::SHF_WRITE | elf::SHF_TLS,
SectionKind::ReadOnlyData => elf::SHF_ALLOC,
SectionKind::ReadOnlyString => {
elf::SHF_ALLOC | elf::SHF_STRINGS | elf::SHF_MERGE
}
SectionKind::OtherString | SectionKind::DebugString => {
elf::SHF_STRINGS | elf::SHF_MERGE
}
SectionKind::Other
| SectionKind::Debug
| SectionKind::Metadata
| SectionKind::Linker
| SectionKind::Note
| SectionKind::Elf(_) => 0,
SectionKind::Unknown | SectionKind::Common | SectionKind::TlsVariables => {
return Err(Error(format!(
"unimplemented section `{}` kind {:?}",
section.name().unwrap_or(""),
section.kind
)));
}
}
.into()
};
// TODO: not sure if this is correct, maybe user should determine this
let sh_entsize = match section.kind {
SectionKind::ReadOnlyString | SectionKind::OtherString => 1,
_ => 0,
};
writer.write_section_header(&SectionHeader {
name: Some(section_offsets[index].str_id),
sh_type,
sh_flags,
sh_addr: 0,
sh_offset: section_offsets[index].offset as u64,
sh_size: section.size,
sh_link: 0,
sh_info: 0,
sh_addralign: section.align,
sh_entsize,
});
if !section.relocations.is_empty() {
writer.write_relocation_section_header(
section_offsets[index].reloc_str_id.unwrap(),
section_offsets[index].index,
symtab_index,
section_offsets[index].reloc_offset,
section.relocations.len(),
is_rela,
);
}
}
writer.write_symtab_section_header(symtab_num_local);
writer.write_symtab_shndx_section_header();
writer.write_strtab_section_header();
writer.write_shstrtab_section_header();
debug_assert_eq!(writer.reserved_len(), writer.len());
Ok(())
}
}