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//===- lib/ReaderWriter/ELF/HeaderChunks.cpp --------------------*- C++ -*-===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "HeaderChunks.h"
#include "TargetLayout.h"
#include "llvm/ADT/STLExtras.h"
namespace lld {
namespace elf {
template <class ELFT> void ELFHeader<ELFT>::finalize() {
_eh.e_ident[llvm::ELF::EI_CLASS] =
(ELFT::Is64Bits) ? llvm::ELF::ELFCLASS64 : llvm::ELF::ELFCLASS32;
_eh.e_ident[llvm::ELF::EI_DATA] =
(ELFT::TargetEndianness == llvm::support::little)
? llvm::ELF::ELFDATA2LSB
: llvm::ELF::ELFDATA2MSB;
_eh.e_type = this->_ctx.getOutputELFType();
_eh.e_machine = this->_ctx.getOutputMachine();
}
template <class ELFT>
ELFHeader<ELFT>::ELFHeader(const ELFLinkingContext &ctx)
: Chunk<ELFT>("elfhdr", Chunk<ELFT>::Kind::ELFHeader, ctx) {
this->_alignment = ELFT::Is64Bits ? 8 : 4;
this->_fsize = sizeof(Elf_Ehdr);
this->_msize = sizeof(Elf_Ehdr);
memset(_eh.e_ident, 0, llvm::ELF::EI_NIDENT);
e_ident(llvm::ELF::EI_MAG0, 0x7f);
e_ident(llvm::ELF::EI_MAG1, 'E');
e_ident(llvm::ELF::EI_MAG2, 'L');
e_ident(llvm::ELF::EI_MAG3, 'F');
e_ehsize(sizeof(Elf_Ehdr));
e_flags(0);
}
template <class ELFT>
void ELFHeader<ELFT>::write(ELFWriter *writer, TargetLayout<ELFT> &layout,
llvm::FileOutputBuffer &buffer) {
uint8_t *chunkBuffer = buffer.getBufferStart();
uint8_t *atomContent = chunkBuffer + this->fileOffset();
memcpy(atomContent, &_eh, fileSize());
}
template <class ELFT>
bool ProgramHeader<ELFT>::addSegment(Segment<ELFT> *segment) {
bool allocatedNew = false;
ELFLinkingContext::OutputMagic outputMagic = this->_ctx.getOutputMagic();
// For segments that are not a loadable segment, we
// just pick the values directly from the segment as there
// wouldnt be any slices within that
if (segment->segmentType() != llvm::ELF::PT_LOAD) {
Elf_Phdr *phdr = allocateProgramHeader(allocatedNew);
phdr->p_type = segment->segmentType();
phdr->p_offset = segment->fileOffset();
phdr->p_vaddr = segment->virtualAddr();
phdr->p_paddr = segment->virtualAddr();
phdr->p_filesz = segment->fileSize();
phdr->p_memsz = segment->memSize();
phdr->p_flags = segment->flags();
phdr->p_align = segment->alignment();
this->_fsize = fileSize();
this->_msize = this->_fsize;
return allocatedNew;
}
// For all other segments, use the slice
// to derive program headers
for (auto slice : segment->slices()) {
Elf_Phdr *phdr = allocateProgramHeader(allocatedNew);
phdr->p_type = segment->segmentType();
phdr->p_offset = slice->fileOffset();
phdr->p_vaddr = slice->virtualAddr();
phdr->p_paddr = slice->virtualAddr();
phdr->p_filesz = slice->fileSize();
phdr->p_memsz = slice->memSize();
phdr->p_flags = segment->flags();
phdr->p_align = slice->alignment();
uint64_t segPageSize = segment->pageSize();
uint64_t sliceAlign = slice->alignment();
// Alignment of PT_LOAD segments are set to the page size, but if the
// alignment of the slice is greater than the page size, set the alignment
// of the segment appropriately.
if (outputMagic != ELFLinkingContext::OutputMagic::NMAGIC &&
outputMagic != ELFLinkingContext::OutputMagic::OMAGIC) {
phdr->p_align =
(phdr->p_type == llvm::ELF::PT_LOAD)
? (segPageSize < sliceAlign) ? sliceAlign : segPageSize
: sliceAlign;
} else
phdr->p_align = slice->alignment();
}
this->_fsize = fileSize();
this->_msize = this->_fsize;
return allocatedNew;
}
template <class ELFT>
void ProgramHeader<ELFT>::write(ELFWriter *writer, TargetLayout<ELFT> &layout,
llvm::FileOutputBuffer &buffer) {
uint8_t *chunkBuffer = buffer.getBufferStart();
uint8_t *dest = chunkBuffer + this->fileOffset();
for (auto phi : _ph) {
memcpy(dest, phi, sizeof(Elf_Phdr));
dest += sizeof(Elf_Phdr);
}
}
template <class ELFT>
typename ProgramHeader<ELFT>::Elf_Phdr *
ProgramHeader<ELFT>::allocateProgramHeader(bool &allocatedNew) {
Elf_Phdr *phdr;
if (_phi == _ph.end()) {
phdr = new (_allocator) Elf_Phdr;
_ph.push_back(phdr);
_phi = _ph.end();
allocatedNew = true;
} else {
phdr = (*_phi);
++_phi;
}
return phdr;
}
template <class ELFT>
SectionHeader<ELFT>::SectionHeader(const ELFLinkingContext &ctx, int32_t order)
: Chunk<ELFT>("shdr", Chunk<ELFT>::Kind::SectionHeader, ctx) {
this->_fsize = 0;
this->_alignment = 8;
this->setOrder(order);
// The first element in the list is always NULL
auto *nullshdr = new (_sectionAllocate.Allocate<Elf_Shdr>()) Elf_Shdr;
::memset(nullshdr, 0, sizeof(Elf_Shdr));
_sectionInfo.push_back(nullshdr);
this->_fsize += sizeof(Elf_Shdr);
}
template <class ELFT>
void SectionHeader<ELFT>::appendSection(OutputSection<ELFT> *section) {
auto *shdr = new (_sectionAllocate.Allocate<Elf_Shdr>()) Elf_Shdr;
shdr->sh_name = _stringSection->addString(section->name());
shdr->sh_type = section->type();
shdr->sh_flags = section->flags();
shdr->sh_offset = section->fileOffset();
shdr->sh_addr = section->virtualAddr();
if (section->isLoadableSection())
shdr->sh_size = section->memSize();
else
shdr->sh_size = section->fileSize();
shdr->sh_link = section->link();
shdr->sh_info = section->shinfo();
shdr->sh_addralign = section->alignment();
shdr->sh_entsize = section->entsize();
_sectionInfo.push_back(shdr);
}
template <class ELFT>
void SectionHeader<ELFT>::updateSection(Section<ELFT> *section) {
Elf_Shdr *shdr = _sectionInfo[section->ordinal()];
shdr->sh_type = section->getType();
shdr->sh_flags = section->getFlags();
shdr->sh_offset = section->fileOffset();
shdr->sh_addr = section->virtualAddr();
shdr->sh_size = section->fileSize();
shdr->sh_link = section->getLink();
shdr->sh_info = section->getInfo();
shdr->sh_addralign = section->alignment();
shdr->sh_entsize = section->getEntSize();
}
template <class ELFT>
void SectionHeader<ELFT>::write(ELFWriter *writer, TargetLayout<ELFT> &layout,
llvm::FileOutputBuffer &buffer) {
uint8_t *chunkBuffer = buffer.getBufferStart();
uint8_t *dest = chunkBuffer + this->fileOffset();
for (auto shi : _sectionInfo) {
memcpy(dest, shi, sizeof(Elf_Shdr));
dest += sizeof(Elf_Shdr);
}
_stringSection->write(writer, layout, buffer);
}
template class ELFHeader<ELF32LE>;
template class ELFHeader<ELF32BE>;
template class ELFHeader<ELF64LE>;
template class ELFHeader<ELF64BE>;
template class ProgramHeader<ELF32LE>;
template class ProgramHeader<ELF32BE>;
template class ProgramHeader<ELF64LE>;
template class ProgramHeader<ELF64BE>;
template class SectionHeader<ELF32LE>;
template class SectionHeader<ELF32BE>;
template class SectionHeader<ELF64LE>;
template class SectionHeader<ELF64BE>;
} // end namespace elf
} // end namespace lld
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