mozilla-central/third_party/rust/object/src/write/xcoff.rs

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use core::mem;
use crate::endian::{BigEndian as BE, I16, U16, U32};
use crate::write::string::*;
use crate::write::util::*;
use crate::write::*;
use crate::{xcoff, AddressSize};
#[derive(Default, Clone, Copy)]
struct SectionOffsets {
address: u64,
data_offset: usize,
reloc_offset: usize,
}
#[derive(Default, Clone, Copy)]
struct SymbolOffsets {
index: usize,
str_id: Option<StringId>,
aux_count: u8,
storage_class: u8,
}
impl<'a> Object<'a> {
pub(crate) fn xcoff_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::ReadOnlyDataWithRel
| StandardSection::ReadOnlyString => (
&[],
&b".rdata"[..],
SectionKind::ReadOnlyData,
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 => {
// Unsupported section.
(&[], &[], SectionKind::Note, SectionFlags::None)
}
}
}
pub(crate) fn xcoff_fixup_relocation(&mut self, mut relocation: &mut Relocation) -> i64 {
let constant = match relocation.kind {
RelocationKind::Relative => relocation.addend + 4,
_ => relocation.addend,
};
relocation.addend -= constant;
constant
}
pub(crate) fn xcoff_write(&self, buffer: &mut dyn WritableBuffer) -> Result<()> {
let is_64 = match self.architecture.address_size().unwrap() {
AddressSize::U8 | AddressSize::U16 | AddressSize::U32 => false,
AddressSize::U64 => true,
};
let (hdr_size, sechdr_size, rel_size, sym_size) = if is_64 {
(
mem::size_of::<xcoff::FileHeader64>(),
mem::size_of::<xcoff::SectionHeader64>(),
mem::size_of::<xcoff::Rel64>(),
mem::size_of::<xcoff::Symbol64>(),
)
} else {
(
mem::size_of::<xcoff::FileHeader32>(),
mem::size_of::<xcoff::SectionHeader32>(),
mem::size_of::<xcoff::Rel32>(),
mem::size_of::<xcoff::Symbol32>(),
)
};
// Calculate offsets and build strtab.
let mut offset = 0;
let mut strtab = StringTable::default();
// We place the shared address 0 immediately after the section header table.
let mut address = 0;
// XCOFF file header.
offset += hdr_size;
// Section headers.
offset += self.sections.len() * sechdr_size;
// Calculate size of section data.
let mut section_offsets = vec![SectionOffsets::default(); self.sections.len()];
for (index, section) in self.sections.iter().enumerate() {
let len = section.data.len();
let sectype = section.kind;
// Section address should be 0 for all sections except the .text, .data, and .bss sections.
if sectype == SectionKind::Data
|| sectype == SectionKind::Text
|| sectype == SectionKind::UninitializedData
{
section_offsets[index].address = address as u64;
address += len;
address = align(address, 4);
} else {
section_offsets[index].address = 0;
}
if len != 0 {
// Set the default section alignment as 4.
offset = align(offset, 4);
section_offsets[index].data_offset = offset;
offset += len;
} else {
section_offsets[index].data_offset = 0;
}
}
// 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 = offset;
offset += count * rel_size;
} else {
section_offsets[index].reloc_offset = 0;
}
}
// Calculate size of symbols.
let mut file_str_id = None;
let mut symbol_offsets = vec![SymbolOffsets::default(); self.symbols.len()];
let mut symtab_count = 0;
for (index, symbol) in self.symbols.iter().enumerate() {
symbol_offsets[index].index = symtab_count;
symtab_count += 1;
let storage_class = if let SymbolFlags::Xcoff { n_sclass, .. } = symbol.flags {
n_sclass
} else {
match symbol.kind {
SymbolKind::Null => xcoff::C_NULL,
SymbolKind::File => xcoff::C_FILE,
SymbolKind::Text | SymbolKind::Data | SymbolKind::Tls => {
if symbol.is_local() {
xcoff::C_STAT
} else if symbol.weak {
xcoff::C_WEAKEXT
} else {
xcoff::C_EXT
}
}
SymbolKind::Section | SymbolKind::Label | SymbolKind::Unknown => {
return Err(Error(format!(
"unimplemented symbol `{}` kind {:?}",
symbol.name().unwrap_or(""),
symbol.kind
)));
}
}
};
symbol_offsets[index].storage_class = storage_class;
if storage_class == xcoff::C_FILE {
if is_64 && file_str_id.is_none() {
file_str_id = Some(strtab.add(b".file"));
}
if symbol.name.len() > 8 {
symbol_offsets[index].str_id = Some(strtab.add(&symbol.name));
}
} else if is_64 || symbol.name.len() > 8 {
symbol_offsets[index].str_id = Some(strtab.add(&symbol.name));
}
symbol_offsets[index].aux_count = 0;
match storage_class {
xcoff::C_FILE => {
symbol_offsets[index].aux_count = 1;
symtab_count += 1;
}
xcoff::C_EXT | xcoff::C_WEAKEXT | xcoff::C_HIDEXT => {
symbol_offsets[index].aux_count = 1;
symtab_count += 1;
}
// TODO: support auxiliary entry for other types of symbol.
_ => {}
}
}
let symtab_offset = offset;
let symtab_len = symtab_count * sym_size;
offset += symtab_len;
// Calculate size of strtab.
let strtab_offset = offset;
let mut strtab_data = Vec::new();
// First 4 bytes of strtab are the length.
strtab.write(4, &mut strtab_data);
let strtab_len = strtab_data.len() + 4;
offset += strtab_len;
// Start writing.
buffer
.reserve(offset)
.map_err(|_| Error(String::from("Cannot allocate buffer")))?;
// Write file header.
if is_64 {
let header = xcoff::FileHeader64 {
f_magic: U16::new(BE, xcoff::MAGIC_64),
f_nscns: U16::new(BE, self.sections.len() as u16),
f_timdat: U32::new(BE, 0),
f_symptr: U64::new(BE, symtab_offset as u64),
f_nsyms: U32::new(BE, symtab_count as u32),
f_opthdr: U16::new(BE, 0),
f_flags: match self.flags {
FileFlags::Xcoff { f_flags } => U16::new(BE, f_flags),
_ => U16::default(),
},
};
buffer.write(&header);
} else {
let header = xcoff::FileHeader32 {
f_magic: U16::new(BE, xcoff::MAGIC_32),
f_nscns: U16::new(BE, self.sections.len() as u16),
f_timdat: U32::new(BE, 0),
f_symptr: U32::new(BE, symtab_offset as u32),
f_nsyms: U32::new(BE, symtab_count as u32),
f_opthdr: U16::new(BE, 0),
f_flags: match self.flags {
FileFlags::Xcoff { f_flags } => U16::new(BE, f_flags),
_ => U16::default(),
},
};
buffer.write(&header);
}
// Write section headers.
for (index, section) in self.sections.iter().enumerate() {
let mut sectname = [0; 8];
sectname
.get_mut(..section.name.len())
.ok_or_else(|| {
Error(format!(
"section name `{}` is too long",
section.name().unwrap_or(""),
))
})?
.copy_from_slice(&section.name);
let flags = if let SectionFlags::Xcoff { s_flags } = section.flags {
s_flags
} else {
match section.kind {
SectionKind::Text
| SectionKind::ReadOnlyData
| SectionKind::ReadOnlyString
| SectionKind::ReadOnlyDataWithRel => xcoff::STYP_TEXT,
SectionKind::Data => xcoff::STYP_DATA,
SectionKind::UninitializedData => xcoff::STYP_BSS,
SectionKind::Tls => xcoff::STYP_TDATA,
SectionKind::UninitializedTls => xcoff::STYP_TBSS,
SectionKind::OtherString => xcoff::STYP_INFO,
SectionKind::Debug => xcoff::STYP_DEBUG,
SectionKind::Other | SectionKind::Metadata => 0,
SectionKind::Note
| SectionKind::Linker
| SectionKind::Common
| SectionKind::Unknown
| SectionKind::TlsVariables
| SectionKind::Elf(_) => {
return Err(Error(format!(
"unimplemented section `{}` kind {:?}",
section.name().unwrap_or(""),
section.kind
)));
}
}
.into()
};
if is_64 {
let section_header = xcoff::SectionHeader64 {
s_name: sectname,
s_paddr: U64::new(BE, section_offsets[index].address),
// This field has the same value as the s_paddr field.
s_vaddr: U64::new(BE, section_offsets[index].address),
s_size: U64::new(BE, section.data.len() as u64),
s_scnptr: U64::new(BE, section_offsets[index].data_offset as u64),
s_relptr: U64::new(BE, section_offsets[index].reloc_offset as u64),
s_lnnoptr: U64::new(BE, 0),
s_nreloc: U32::new(BE, section.relocations.len() as u32),
s_nlnno: U32::new(BE, 0),
s_flags: U32::new(BE, flags),
s_reserve: U32::new(BE, 0),
};
buffer.write(&section_header);
} else {
let section_header = xcoff::SectionHeader32 {
s_name: sectname,
s_paddr: U32::new(BE, section_offsets[index].address as u32),
// This field has the same value as the s_paddr field.
s_vaddr: U32::new(BE, section_offsets[index].address as u32),
s_size: U32::new(BE, section.data.len() as u32),
s_scnptr: U32::new(BE, section_offsets[index].data_offset as u32),
s_relptr: U32::new(BE, section_offsets[index].reloc_offset as u32),
s_lnnoptr: U32::new(BE, 0),
// TODO: If more than 65,534 relocation entries are required, the field
// value will be 65535, and an STYP_OVRFLO section header will contain
// the actual count of relocation entries in the s_paddr field.
s_nreloc: U16::new(BE, section.relocations.len() as u16),
s_nlnno: U16::new(BE, 0),
s_flags: U32::new(BE, flags),
};
buffer.write(&section_header);
}
}
// Write section data.
for (index, section) in self.sections.iter().enumerate() {
let len = section.data.len();
if len != 0 {
write_align(buffer, 4);
debug_assert_eq!(section_offsets[index].data_offset, buffer.len());
buffer.write_bytes(&section.data);
}
}
// Write relocations.
for (index, section) in self.sections.iter().enumerate() {
if !section.relocations.is_empty() {
debug_assert_eq!(section_offsets[index].reloc_offset, buffer.len());
for reloc in &section.relocations {
let rtype = match reloc.kind {
RelocationKind::Absolute => xcoff::R_POS,
RelocationKind::Relative => xcoff::R_REL,
RelocationKind::Got => xcoff::R_TOC,
RelocationKind::Xcoff(x) => x,
_ => {
return Err(Error(format!("unimplemented relocation {:?}", reloc)));
}
};
if is_64 {
let xcoff_rel = xcoff::Rel64 {
r_vaddr: U64::new(BE, reloc.offset),
r_symndx: U32::new(BE, symbol_offsets[reloc.symbol.0].index as u32),
// Specifies the bit length of the relocatable reference minus one.
r_rsize: (reloc.size - 1),
r_rtype: rtype,
};
buffer.write(&xcoff_rel);
} else {
let xcoff_rel = xcoff::Rel32 {
r_vaddr: U32::new(BE, reloc.offset as u32),
r_symndx: U32::new(BE, symbol_offsets[reloc.symbol.0].index as u32),
r_rsize: (reloc.size - 1),
r_rtype: rtype,
};
buffer.write(&xcoff_rel);
}
}
}
}
// Write symbols.
debug_assert_eq!(symtab_offset, buffer.len());
for (index, symbol) in self.symbols.iter().enumerate() {
let (n_value, section_kind) = if let SymbolSection::Section(id) = symbol.section {
(
section_offsets[id.0].address + symbol.value,
self.sections[id.0].kind,
)
} else {
(symbol.value, SectionKind::Unknown)
};
let n_scnum = match symbol.section {
SymbolSection::None => {
debug_assert_eq!(symbol.kind, SymbolKind::File);
xcoff::N_DEBUG
}
SymbolSection::Undefined | SymbolSection::Common => xcoff::N_UNDEF,
SymbolSection::Absolute => xcoff::N_ABS,
SymbolSection::Section(id) => id.0 as i16 + 1,
};
let n_sclass = symbol_offsets[index].storage_class;
let n_type = if (symbol.scope == SymbolScope::Linkage)
&& (n_sclass == xcoff::C_EXT
|| n_sclass == xcoff::C_WEAKEXT
|| n_sclass == xcoff::C_HIDEXT)
{
xcoff::SYM_V_HIDDEN
} else {
0
};
let n_numaux = symbol_offsets[index].aux_count;
if is_64 {
let str_id = if n_sclass == xcoff::C_FILE {
file_str_id.unwrap()
} else {
symbol_offsets[index].str_id.unwrap()
};
let xcoff_sym = xcoff::Symbol64 {
n_value: U64::new(BE, n_value),
n_offset: U32::new(BE, strtab.get_offset(str_id) as u32),
n_scnum: I16::new(BE, n_scnum),
n_type: U16::new(BE, n_type),
n_sclass,
n_numaux,
};
buffer.write(&xcoff_sym);
} else {
let mut sym_name = [0; 8];
if n_sclass == xcoff::C_FILE {
sym_name[..5].copy_from_slice(b".file");
} else if symbol.name.len() <= 8 {
sym_name[..symbol.name.len()].copy_from_slice(&symbol.name[..]);
} else {
let str_offset = strtab.get_offset(symbol_offsets[index].str_id.unwrap());
sym_name[4..8].copy_from_slice(&u32::to_be_bytes(str_offset as u32));
}
let xcoff_sym = xcoff::Symbol32 {
n_name: sym_name,
n_value: U32::new(BE, n_value as u32),
n_scnum: I16::new(BE, n_scnum),
n_type: U16::new(BE, n_type),
n_sclass,
n_numaux,
};
buffer.write(&xcoff_sym);
}
// Generate auxiliary entries.
if n_sclass == xcoff::C_FILE {
debug_assert_eq!(n_numaux, 1);
let mut x_fname = [0; 8];
if symbol.name.len() <= 8 {
x_fname[..symbol.name.len()].copy_from_slice(&symbol.name[..]);
} else {
let str_offset = strtab.get_offset(symbol_offsets[index].str_id.unwrap());
x_fname[4..8].copy_from_slice(&u32::to_be_bytes(str_offset as u32));
}
if is_64 {
let file_aux = xcoff::FileAux64 {
x_fname,
x_fpad: Default::default(),
x_ftype: xcoff::XFT_FN,
x_freserve: Default::default(),
x_auxtype: xcoff::AUX_FILE,
};
buffer.write(&file_aux);
} else {
let file_aux = xcoff::FileAux32 {
x_fname,
x_fpad: Default::default(),
x_ftype: xcoff::XFT_FN,
x_freserve: Default::default(),
};
buffer.write(&file_aux);
}
} else if n_sclass == xcoff::C_EXT
|| n_sclass == xcoff::C_WEAKEXT
|| n_sclass == xcoff::C_HIDEXT
{
debug_assert_eq!(n_numaux, 1);
let (x_smtyp, x_smclas) = if let SymbolFlags::Xcoff {
x_smtyp, x_smclas, ..
} = symbol.flags
{
(x_smtyp, x_smclas)
} else {
match symbol.kind {
SymbolKind::Text => (xcoff::XTY_SD, xcoff::XMC_PR),
SymbolKind::Data => {
if section_kind == SectionKind::UninitializedData {
(xcoff::XTY_CM, xcoff::XMC_BS)
} else if section_kind == SectionKind::ReadOnlyData {
(xcoff::XTY_SD, xcoff::XMC_RO)
} else {
(xcoff::XTY_SD, xcoff::XMC_RW)
}
}
SymbolKind::Tls => {
if section_kind == SectionKind::UninitializedTls {
(xcoff::XTY_CM, xcoff::XMC_UL)
} else {
(xcoff::XTY_SD, xcoff::XMC_TL)
}
}
_ => {
return Err(Error(format!(
"unimplemented symbol `{}` kind {:?}",
symbol.name().unwrap_or(""),
symbol.kind
)));
}
}
};
let scnlen = if let SymbolFlags::Xcoff {
containing_csect: Some(containing_csect),
..
} = symbol.flags
{
symbol_offsets[containing_csect.0].index as u64
} else {
symbol.size
};
if is_64 {
let csect_aux = xcoff::CsectAux64 {
x_scnlen_lo: U32::new(BE, (scnlen & 0xFFFFFFFF) as u32),
x_scnlen_hi: U32::new(BE, ((scnlen >> 32) & 0xFFFFFFFF) as u32),
x_parmhash: U32::new(BE, 0),
x_snhash: U16::new(BE, 0),
x_smtyp,
x_smclas,
pad: 0,
x_auxtype: xcoff::AUX_CSECT,
};
buffer.write(&csect_aux);
} else {
let csect_aux = xcoff::CsectAux32 {
x_scnlen: U32::new(BE, scnlen as u32),
x_parmhash: U32::new(BE, 0),
x_snhash: U16::new(BE, 0),
x_smtyp,
x_smclas,
x_stab: U32::new(BE, 0),
x_snstab: U16::new(BE, 0),
};
buffer.write(&csect_aux);
}
}
}
// Write string table.
debug_assert_eq!(strtab_offset, buffer.len());
buffer.write_bytes(&u32::to_be_bytes(strtab_len as u32));
buffer.write_bytes(&strtab_data);
debug_assert_eq!(offset, buffer.len());
Ok(())
}
}