forked from OSchip/llvm-project
1643 lines
59 KiB
C++
1643 lines
59 KiB
C++
//===- InputFiles.cpp -----------------------------------------------------===//
|
|
//
|
|
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
|
|
// See https://llvm.org/LICENSE.txt for license information.
|
|
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "InputFiles.h"
|
|
#include "Driver.h"
|
|
#include "InputSection.h"
|
|
#include "LinkerScript.h"
|
|
#include "SymbolTable.h"
|
|
#include "Symbols.h"
|
|
#include "SyntheticSections.h"
|
|
#include "lld/Common/ErrorHandler.h"
|
|
#include "lld/Common/Memory.h"
|
|
#include "llvm/ADT/STLExtras.h"
|
|
#include "llvm/CodeGen/Analysis.h"
|
|
#include "llvm/DebugInfo/DWARF/DWARFContext.h"
|
|
#include "llvm/IR/LLVMContext.h"
|
|
#include "llvm/IR/Module.h"
|
|
#include "llvm/LTO/LTO.h"
|
|
#include "llvm/MC/StringTableBuilder.h"
|
|
#include "llvm/Object/ELFObjectFile.h"
|
|
#include "llvm/Support/ARMAttributeParser.h"
|
|
#include "llvm/Support/ARMBuildAttributes.h"
|
|
#include "llvm/Support/Endian.h"
|
|
#include "llvm/Support/Path.h"
|
|
#include "llvm/Support/TarWriter.h"
|
|
#include "llvm/Support/raw_ostream.h"
|
|
|
|
using namespace llvm;
|
|
using namespace llvm::ELF;
|
|
using namespace llvm::object;
|
|
using namespace llvm::sys;
|
|
using namespace llvm::sys::fs;
|
|
using namespace llvm::support::endian;
|
|
|
|
using namespace lld;
|
|
using namespace lld::elf;
|
|
|
|
bool InputFile::IsInGroup;
|
|
uint32_t InputFile::NextGroupId;
|
|
std::vector<BinaryFile *> elf::BinaryFiles;
|
|
std::vector<BitcodeFile *> elf::BitcodeFiles;
|
|
std::vector<LazyObjFile *> elf::LazyObjFiles;
|
|
std::vector<InputFile *> elf::ObjectFiles;
|
|
std::vector<SharedFile *> elf::SharedFiles;
|
|
|
|
std::unique_ptr<TarWriter> elf::Tar;
|
|
|
|
static ELFKind getELFKind(MemoryBufferRef MB, StringRef ArchiveName) {
|
|
unsigned char Size;
|
|
unsigned char Endian;
|
|
std::tie(Size, Endian) = getElfArchType(MB.getBuffer());
|
|
|
|
auto Fatal = [&](StringRef Msg) {
|
|
StringRef Filename = MB.getBufferIdentifier();
|
|
if (ArchiveName.empty())
|
|
fatal(Filename + ": " + Msg);
|
|
else
|
|
fatal(ArchiveName + "(" + Filename + "): " + Msg);
|
|
};
|
|
|
|
if (!MB.getBuffer().startswith(ElfMagic))
|
|
Fatal("not an ELF file");
|
|
if (Endian != ELFDATA2LSB && Endian != ELFDATA2MSB)
|
|
Fatal("corrupted ELF file: invalid data encoding");
|
|
if (Size != ELFCLASS32 && Size != ELFCLASS64)
|
|
Fatal("corrupted ELF file: invalid file class");
|
|
|
|
size_t BufSize = MB.getBuffer().size();
|
|
if ((Size == ELFCLASS32 && BufSize < sizeof(Elf32_Ehdr)) ||
|
|
(Size == ELFCLASS64 && BufSize < sizeof(Elf64_Ehdr)))
|
|
Fatal("corrupted ELF file: file is too short");
|
|
|
|
if (Size == ELFCLASS32)
|
|
return (Endian == ELFDATA2LSB) ? ELF32LEKind : ELF32BEKind;
|
|
return (Endian == ELFDATA2LSB) ? ELF64LEKind : ELF64BEKind;
|
|
}
|
|
|
|
InputFile::InputFile(Kind K, MemoryBufferRef M)
|
|
: MB(M), GroupId(NextGroupId), FileKind(K) {
|
|
// All files within the same --{start,end}-group get the same group ID.
|
|
// Otherwise, a new file will get a new group ID.
|
|
if (!IsInGroup)
|
|
++NextGroupId;
|
|
}
|
|
|
|
Optional<MemoryBufferRef> elf::readFile(StringRef Path) {
|
|
// The --chroot option changes our virtual root directory.
|
|
// This is useful when you are dealing with files created by --reproduce.
|
|
if (!Config->Chroot.empty() && Path.startswith("/"))
|
|
Path = Saver.save(Config->Chroot + Path);
|
|
|
|
log(Path);
|
|
|
|
auto MBOrErr = MemoryBuffer::getFile(Path, -1, false);
|
|
if (auto EC = MBOrErr.getError()) {
|
|
error("cannot open " + Path + ": " + EC.message());
|
|
return None;
|
|
}
|
|
|
|
std::unique_ptr<MemoryBuffer> &MB = *MBOrErr;
|
|
MemoryBufferRef MBRef = MB->getMemBufferRef();
|
|
make<std::unique_ptr<MemoryBuffer>>(std::move(MB)); // take MB ownership
|
|
|
|
if (Tar)
|
|
Tar->append(relativeToRoot(Path), MBRef.getBuffer());
|
|
return MBRef;
|
|
}
|
|
|
|
// All input object files must be for the same architecture
|
|
// (e.g. it does not make sense to link x86 object files with
|
|
// MIPS object files.) This function checks for that error.
|
|
static bool isCompatible(InputFile *File) {
|
|
if (!File->isElf() && !isa<BitcodeFile>(File))
|
|
return true;
|
|
|
|
if (File->EKind == Config->EKind && File->EMachine == Config->EMachine) {
|
|
if (Config->EMachine != EM_MIPS)
|
|
return true;
|
|
if (isMipsN32Abi(File) == Config->MipsN32Abi)
|
|
return true;
|
|
}
|
|
|
|
if (!Config->Emulation.empty()) {
|
|
error(toString(File) + " is incompatible with " + Config->Emulation);
|
|
} else {
|
|
InputFile *Existing;
|
|
if (!ObjectFiles.empty())
|
|
Existing = ObjectFiles[0];
|
|
else if (!SharedFiles.empty())
|
|
Existing = SharedFiles[0];
|
|
else
|
|
Existing = BitcodeFiles[0];
|
|
|
|
error(toString(File) + " is incompatible with " + toString(Existing));
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
template <class ELFT> static void doParseFile(InputFile *File) {
|
|
if (!isCompatible(File))
|
|
return;
|
|
|
|
// Binary file
|
|
if (auto *F = dyn_cast<BinaryFile>(File)) {
|
|
BinaryFiles.push_back(F);
|
|
F->parse();
|
|
return;
|
|
}
|
|
|
|
// .a file
|
|
if (auto *F = dyn_cast<ArchiveFile>(File)) {
|
|
F->parse();
|
|
return;
|
|
}
|
|
|
|
// Lazy object file
|
|
if (auto *F = dyn_cast<LazyObjFile>(File)) {
|
|
LazyObjFiles.push_back(F);
|
|
F->parse<ELFT>();
|
|
return;
|
|
}
|
|
|
|
if (Config->Trace)
|
|
message(toString(File));
|
|
|
|
// .so file
|
|
if (auto *F = dyn_cast<SharedFile>(File)) {
|
|
F->parse<ELFT>();
|
|
return;
|
|
}
|
|
|
|
// LLVM bitcode file
|
|
if (auto *F = dyn_cast<BitcodeFile>(File)) {
|
|
BitcodeFiles.push_back(F);
|
|
F->parse<ELFT>(Symtab->ComdatGroups);
|
|
return;
|
|
}
|
|
|
|
// Regular object file
|
|
ObjectFiles.push_back(File);
|
|
cast<ObjFile<ELFT>>(File)->parse(Symtab->ComdatGroups);
|
|
}
|
|
|
|
// Add symbols in File to the symbol table.
|
|
void elf::parseFile(InputFile *File) {
|
|
switch (Config->EKind) {
|
|
case ELF32LEKind:
|
|
doParseFile<ELF32LE>(File);
|
|
return;
|
|
case ELF32BEKind:
|
|
doParseFile<ELF32BE>(File);
|
|
return;
|
|
case ELF64LEKind:
|
|
doParseFile<ELF64LE>(File);
|
|
return;
|
|
case ELF64BEKind:
|
|
doParseFile<ELF64BE>(File);
|
|
return;
|
|
default:
|
|
llvm_unreachable("unknown ELFT");
|
|
}
|
|
}
|
|
|
|
// Concatenates arguments to construct a string representing an error location.
|
|
static std::string createFileLineMsg(StringRef Path, unsigned Line) {
|
|
std::string Filename = path::filename(Path);
|
|
std::string Lineno = ":" + std::to_string(Line);
|
|
if (Filename == Path)
|
|
return Filename + Lineno;
|
|
return Filename + Lineno + " (" + Path.str() + Lineno + ")";
|
|
}
|
|
|
|
template <class ELFT>
|
|
static std::string getSrcMsgAux(ObjFile<ELFT> &File, const Symbol &Sym,
|
|
InputSectionBase &Sec, uint64_t Offset) {
|
|
// In DWARF, functions and variables are stored to different places.
|
|
// First, lookup a function for a given offset.
|
|
if (Optional<DILineInfo> Info = File.getDILineInfo(&Sec, Offset))
|
|
return createFileLineMsg(Info->FileName, Info->Line);
|
|
|
|
// If it failed, lookup again as a variable.
|
|
if (Optional<std::pair<std::string, unsigned>> FileLine =
|
|
File.getVariableLoc(Sym.getName()))
|
|
return createFileLineMsg(FileLine->first, FileLine->second);
|
|
|
|
// File.SourceFile contains STT_FILE symbol, and that is a last resort.
|
|
return File.SourceFile;
|
|
}
|
|
|
|
std::string InputFile::getSrcMsg(const Symbol &Sym, InputSectionBase &Sec,
|
|
uint64_t Offset) {
|
|
if (kind() != ObjKind)
|
|
return "";
|
|
switch (Config->EKind) {
|
|
default:
|
|
llvm_unreachable("Invalid kind");
|
|
case ELF32LEKind:
|
|
return getSrcMsgAux(cast<ObjFile<ELF32LE>>(*this), Sym, Sec, Offset);
|
|
case ELF32BEKind:
|
|
return getSrcMsgAux(cast<ObjFile<ELF32BE>>(*this), Sym, Sec, Offset);
|
|
case ELF64LEKind:
|
|
return getSrcMsgAux(cast<ObjFile<ELF64LE>>(*this), Sym, Sec, Offset);
|
|
case ELF64BEKind:
|
|
return getSrcMsgAux(cast<ObjFile<ELF64BE>>(*this), Sym, Sec, Offset);
|
|
}
|
|
}
|
|
|
|
template <class ELFT> void ObjFile<ELFT>::initializeDwarf() {
|
|
Dwarf = llvm::make_unique<DWARFContext>(make_unique<LLDDwarfObj<ELFT>>(this));
|
|
for (std::unique_ptr<DWARFUnit> &CU : Dwarf->compile_units()) {
|
|
auto Report = [](Error Err) {
|
|
handleAllErrors(std::move(Err),
|
|
[](ErrorInfoBase &Info) { warn(Info.message()); });
|
|
};
|
|
Expected<const DWARFDebugLine::LineTable *> ExpectedLT =
|
|
Dwarf->getLineTableForUnit(CU.get(), Report);
|
|
const DWARFDebugLine::LineTable *LT = nullptr;
|
|
if (ExpectedLT)
|
|
LT = *ExpectedLT;
|
|
else
|
|
Report(ExpectedLT.takeError());
|
|
if (!LT)
|
|
continue;
|
|
LineTables.push_back(LT);
|
|
|
|
// Loop over variable records and insert them to VariableLoc.
|
|
for (const auto &Entry : CU->dies()) {
|
|
DWARFDie Die(CU.get(), &Entry);
|
|
// Skip all tags that are not variables.
|
|
if (Die.getTag() != dwarf::DW_TAG_variable)
|
|
continue;
|
|
|
|
// Skip if a local variable because we don't need them for generating
|
|
// error messages. In general, only non-local symbols can fail to be
|
|
// linked.
|
|
if (!dwarf::toUnsigned(Die.find(dwarf::DW_AT_external), 0))
|
|
continue;
|
|
|
|
// Get the source filename index for the variable.
|
|
unsigned File = dwarf::toUnsigned(Die.find(dwarf::DW_AT_decl_file), 0);
|
|
if (!LT->hasFileAtIndex(File))
|
|
continue;
|
|
|
|
// Get the line number on which the variable is declared.
|
|
unsigned Line = dwarf::toUnsigned(Die.find(dwarf::DW_AT_decl_line), 0);
|
|
|
|
// Here we want to take the variable name to add it into VariableLoc.
|
|
// Variable can have regular and linkage name associated. At first, we try
|
|
// to get linkage name as it can be different, for example when we have
|
|
// two variables in different namespaces of the same object. Use common
|
|
// name otherwise, but handle the case when it also absent in case if the
|
|
// input object file lacks some debug info.
|
|
StringRef Name =
|
|
dwarf::toString(Die.find(dwarf::DW_AT_linkage_name),
|
|
dwarf::toString(Die.find(dwarf::DW_AT_name), ""));
|
|
if (!Name.empty())
|
|
VariableLoc.insert({Name, {LT, File, Line}});
|
|
}
|
|
}
|
|
}
|
|
|
|
// Returns the pair of file name and line number describing location of data
|
|
// object (variable, array, etc) definition.
|
|
template <class ELFT>
|
|
Optional<std::pair<std::string, unsigned>>
|
|
ObjFile<ELFT>::getVariableLoc(StringRef Name) {
|
|
llvm::call_once(InitDwarfLine, [this]() { initializeDwarf(); });
|
|
|
|
// Return if we have no debug information about data object.
|
|
auto It = VariableLoc.find(Name);
|
|
if (It == VariableLoc.end())
|
|
return None;
|
|
|
|
// Take file name string from line table.
|
|
std::string FileName;
|
|
if (!It->second.LT->getFileNameByIndex(
|
|
It->second.File, nullptr,
|
|
DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, FileName))
|
|
return None;
|
|
|
|
return std::make_pair(FileName, It->second.Line);
|
|
}
|
|
|
|
// Returns source line information for a given offset
|
|
// using DWARF debug info.
|
|
template <class ELFT>
|
|
Optional<DILineInfo> ObjFile<ELFT>::getDILineInfo(InputSectionBase *S,
|
|
uint64_t Offset) {
|
|
llvm::call_once(InitDwarfLine, [this]() { initializeDwarf(); });
|
|
|
|
// Detect SectionIndex for specified section.
|
|
uint64_t SectionIndex = object::SectionedAddress::UndefSection;
|
|
ArrayRef<InputSectionBase *> Sections = S->File->getSections();
|
|
for (uint64_t CurIndex = 0; CurIndex < Sections.size(); ++CurIndex) {
|
|
if (S == Sections[CurIndex]) {
|
|
SectionIndex = CurIndex;
|
|
break;
|
|
}
|
|
}
|
|
|
|
// Use fake address calcuated by adding section file offset and offset in
|
|
// section. See comments for ObjectInfo class.
|
|
DILineInfo Info;
|
|
for (const llvm::DWARFDebugLine::LineTable *LT : LineTables) {
|
|
if (LT->getFileLineInfoForAddress(
|
|
{S->getOffsetInFile() + Offset, SectionIndex}, nullptr,
|
|
DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, Info))
|
|
return Info;
|
|
}
|
|
return None;
|
|
}
|
|
|
|
// Returns "<internal>", "foo.a(bar.o)" or "baz.o".
|
|
std::string lld::toString(const InputFile *F) {
|
|
if (!F)
|
|
return "<internal>";
|
|
|
|
if (F->ToStringCache.empty()) {
|
|
if (F->ArchiveName.empty())
|
|
F->ToStringCache = F->getName();
|
|
else
|
|
F->ToStringCache = (F->ArchiveName + "(" + F->getName() + ")").str();
|
|
}
|
|
return F->ToStringCache;
|
|
}
|
|
|
|
ELFFileBase::ELFFileBase(Kind K, MemoryBufferRef MB) : InputFile(K, MB) {
|
|
EKind = getELFKind(MB, "");
|
|
|
|
switch (EKind) {
|
|
case ELF32LEKind:
|
|
init<ELF32LE>();
|
|
break;
|
|
case ELF32BEKind:
|
|
init<ELF32BE>();
|
|
break;
|
|
case ELF64LEKind:
|
|
init<ELF64LE>();
|
|
break;
|
|
case ELF64BEKind:
|
|
init<ELF64BE>();
|
|
break;
|
|
default:
|
|
llvm_unreachable("getELFKind");
|
|
}
|
|
}
|
|
|
|
template <typename Elf_Shdr>
|
|
static const Elf_Shdr *findSection(ArrayRef<Elf_Shdr> Sections, uint32_t Type) {
|
|
for (const Elf_Shdr &Sec : Sections)
|
|
if (Sec.sh_type == Type)
|
|
return &Sec;
|
|
return nullptr;
|
|
}
|
|
|
|
template <class ELFT> void ELFFileBase::init() {
|
|
using Elf_Shdr = typename ELFT::Shdr;
|
|
using Elf_Sym = typename ELFT::Sym;
|
|
|
|
// Initialize trivial attributes.
|
|
const ELFFile<ELFT> &Obj = getObj<ELFT>();
|
|
EMachine = Obj.getHeader()->e_machine;
|
|
OSABI = Obj.getHeader()->e_ident[llvm::ELF::EI_OSABI];
|
|
ABIVersion = Obj.getHeader()->e_ident[llvm::ELF::EI_ABIVERSION];
|
|
|
|
ArrayRef<Elf_Shdr> Sections = CHECK(Obj.sections(), this);
|
|
|
|
// Find a symbol table.
|
|
bool IsDSO =
|
|
(identify_magic(MB.getBuffer()) == file_magic::elf_shared_object);
|
|
const Elf_Shdr *SymtabSec =
|
|
findSection(Sections, IsDSO ? SHT_DYNSYM : SHT_SYMTAB);
|
|
|
|
if (!SymtabSec)
|
|
return;
|
|
|
|
// Initialize members corresponding to a symbol table.
|
|
FirstGlobal = SymtabSec->sh_info;
|
|
|
|
ArrayRef<Elf_Sym> ESyms = CHECK(Obj.symbols(SymtabSec), this);
|
|
if (FirstGlobal == 0 || FirstGlobal > ESyms.size())
|
|
fatal(toString(this) + ": invalid sh_info in symbol table");
|
|
|
|
ELFSyms = reinterpret_cast<const void *>(ESyms.data());
|
|
NumELFSyms = ESyms.size();
|
|
StringTable = CHECK(Obj.getStringTableForSymtab(*SymtabSec, Sections), this);
|
|
}
|
|
|
|
template <class ELFT>
|
|
uint32_t ObjFile<ELFT>::getSectionIndex(const Elf_Sym &Sym) const {
|
|
return CHECK(
|
|
this->getObj().getSectionIndex(&Sym, getELFSyms<ELFT>(), ShndxTable),
|
|
this);
|
|
}
|
|
|
|
template <class ELFT> ArrayRef<Symbol *> ObjFile<ELFT>::getLocalSymbols() {
|
|
if (this->Symbols.empty())
|
|
return {};
|
|
return makeArrayRef(this->Symbols).slice(1, this->FirstGlobal - 1);
|
|
}
|
|
|
|
template <class ELFT> ArrayRef<Symbol *> ObjFile<ELFT>::getGlobalSymbols() {
|
|
return makeArrayRef(this->Symbols).slice(this->FirstGlobal);
|
|
}
|
|
|
|
template <class ELFT>
|
|
void ObjFile<ELFT>::parse(
|
|
DenseMap<CachedHashStringRef, const InputFile *> &ComdatGroups) {
|
|
// Read a section table. JustSymbols is usually false.
|
|
if (this->JustSymbols)
|
|
initializeJustSymbols();
|
|
else
|
|
initializeSections(ComdatGroups);
|
|
|
|
// Read a symbol table.
|
|
initializeSymbols();
|
|
}
|
|
|
|
// Sections with SHT_GROUP and comdat bits define comdat section groups.
|
|
// They are identified and deduplicated by group name. This function
|
|
// returns a group name.
|
|
template <class ELFT>
|
|
StringRef ObjFile<ELFT>::getShtGroupSignature(ArrayRef<Elf_Shdr> Sections,
|
|
const Elf_Shdr &Sec) {
|
|
const Elf_Sym *Sym =
|
|
CHECK(object::getSymbol<ELFT>(this->getELFSyms<ELFT>(), Sec.sh_info), this);
|
|
StringRef Signature = CHECK(Sym->getName(this->StringTable), this);
|
|
|
|
// As a special case, if a symbol is a section symbol and has no name,
|
|
// we use a section name as a signature.
|
|
//
|
|
// Such SHT_GROUP sections are invalid from the perspective of the ELF
|
|
// standard, but GNU gold 1.14 (the newest version as of July 2017) or
|
|
// older produce such sections as outputs for the -r option, so we need
|
|
// a bug-compatibility.
|
|
if (Signature.empty() && Sym->getType() == STT_SECTION)
|
|
return getSectionName(Sec);
|
|
return Signature;
|
|
}
|
|
|
|
template <class ELFT> bool ObjFile<ELFT>::shouldMerge(const Elf_Shdr &Sec) {
|
|
// On a regular link we don't merge sections if -O0 (default is -O1). This
|
|
// sometimes makes the linker significantly faster, although the output will
|
|
// be bigger.
|
|
//
|
|
// Doing the same for -r would create a problem as it would combine sections
|
|
// with different sh_entsize. One option would be to just copy every SHF_MERGE
|
|
// section as is to the output. While this would produce a valid ELF file with
|
|
// usable SHF_MERGE sections, tools like (llvm-)?dwarfdump get confused when
|
|
// they see two .debug_str. We could have separate logic for combining
|
|
// SHF_MERGE sections based both on their name and sh_entsize, but that seems
|
|
// to be more trouble than it is worth. Instead, we just use the regular (-O1)
|
|
// logic for -r.
|
|
if (Config->Optimize == 0 && !Config->Relocatable)
|
|
return false;
|
|
|
|
// A mergeable section with size 0 is useless because they don't have
|
|
// any data to merge. A mergeable string section with size 0 can be
|
|
// argued as invalid because it doesn't end with a null character.
|
|
// We'll avoid a mess by handling them as if they were non-mergeable.
|
|
if (Sec.sh_size == 0)
|
|
return false;
|
|
|
|
// Check for sh_entsize. The ELF spec is not clear about the zero
|
|
// sh_entsize. It says that "the member [sh_entsize] contains 0 if
|
|
// the section does not hold a table of fixed-size entries". We know
|
|
// that Rust 1.13 produces a string mergeable section with a zero
|
|
// sh_entsize. Here we just accept it rather than being picky about it.
|
|
uint64_t EntSize = Sec.sh_entsize;
|
|
if (EntSize == 0)
|
|
return false;
|
|
if (Sec.sh_size % EntSize)
|
|
fatal(toString(this) +
|
|
": SHF_MERGE section size must be a multiple of sh_entsize");
|
|
|
|
uint64_t Flags = Sec.sh_flags;
|
|
if (!(Flags & SHF_MERGE))
|
|
return false;
|
|
if (Flags & SHF_WRITE)
|
|
fatal(toString(this) + ": writable SHF_MERGE section is not supported");
|
|
|
|
return true;
|
|
}
|
|
|
|
// This is for --just-symbols.
|
|
//
|
|
// --just-symbols is a very minor feature that allows you to link your
|
|
// output against other existing program, so that if you load both your
|
|
// program and the other program into memory, your output can refer the
|
|
// other program's symbols.
|
|
//
|
|
// When the option is given, we link "just symbols". The section table is
|
|
// initialized with null pointers.
|
|
template <class ELFT> void ObjFile<ELFT>::initializeJustSymbols() {
|
|
ArrayRef<Elf_Shdr> Sections = CHECK(this->getObj().sections(), this);
|
|
this->Sections.resize(Sections.size());
|
|
}
|
|
|
|
// An ELF object file may contain a `.deplibs` section. If it exists, the
|
|
// section contains a list of library specifiers such as `m` for libm. This
|
|
// function resolves a given name by finding the first matching library checking
|
|
// the various ways that a library can be specified to LLD. This ELF extension
|
|
// is a form of autolinking and is called `dependent libraries`. It is currently
|
|
// unique to LLVM and lld.
|
|
static void addDependentLibrary(StringRef Specifier, const InputFile *F) {
|
|
if (!Config->DependentLibraries)
|
|
return;
|
|
if (fs::exists(Specifier))
|
|
Driver->addFile(Specifier, /*WithLOption=*/false);
|
|
else if (Optional<std::string> S = findFromSearchPaths(Specifier))
|
|
Driver->addFile(*S, /*WithLOption=*/true);
|
|
else if (Optional<std::string> S = searchLibraryBaseName(Specifier))
|
|
Driver->addFile(*S, /*WithLOption=*/true);
|
|
else
|
|
error(toString(F) +
|
|
": unable to find library from dependent library specifier: " +
|
|
Specifier);
|
|
}
|
|
|
|
template <class ELFT>
|
|
void ObjFile<ELFT>::initializeSections(
|
|
DenseMap<CachedHashStringRef, const InputFile *> &ComdatGroups) {
|
|
const ELFFile<ELFT> &Obj = this->getObj();
|
|
|
|
ArrayRef<Elf_Shdr> ObjSections = CHECK(Obj.sections(), this);
|
|
uint64_t Size = ObjSections.size();
|
|
this->Sections.resize(Size);
|
|
this->SectionStringTable =
|
|
CHECK(Obj.getSectionStringTable(ObjSections), this);
|
|
|
|
for (size_t I = 0, E = ObjSections.size(); I < E; I++) {
|
|
if (this->Sections[I] == &InputSection::Discarded)
|
|
continue;
|
|
const Elf_Shdr &Sec = ObjSections[I];
|
|
|
|
if (Sec.sh_type == ELF::SHT_LLVM_CALL_GRAPH_PROFILE)
|
|
CGProfile =
|
|
check(Obj.template getSectionContentsAsArray<Elf_CGProfile>(&Sec));
|
|
|
|
// SHF_EXCLUDE'ed sections are discarded by the linker. However,
|
|
// if -r is given, we'll let the final link discard such sections.
|
|
// This is compatible with GNU.
|
|
if ((Sec.sh_flags & SHF_EXCLUDE) && !Config->Relocatable) {
|
|
if (Sec.sh_type == SHT_LLVM_ADDRSIG) {
|
|
// We ignore the address-significance table if we know that the object
|
|
// file was created by objcopy or ld -r. This is because these tools
|
|
// will reorder the symbols in the symbol table, invalidating the data
|
|
// in the address-significance table, which refers to symbols by index.
|
|
if (Sec.sh_link != 0)
|
|
this->AddrsigSec = &Sec;
|
|
else if (Config->ICF == ICFLevel::Safe)
|
|
warn(toString(this) + ": --icf=safe is incompatible with object "
|
|
"files created using objcopy or ld -r");
|
|
}
|
|
this->Sections[I] = &InputSection::Discarded;
|
|
continue;
|
|
}
|
|
|
|
switch (Sec.sh_type) {
|
|
case SHT_GROUP: {
|
|
// De-duplicate section groups by their signatures.
|
|
StringRef Signature = getShtGroupSignature(ObjSections, Sec);
|
|
this->Sections[I] = &InputSection::Discarded;
|
|
|
|
|
|
ArrayRef<Elf_Word> Entries =
|
|
CHECK(Obj.template getSectionContentsAsArray<Elf_Word>(&Sec), this);
|
|
if (Entries.empty())
|
|
fatal(toString(this) + ": empty SHT_GROUP");
|
|
|
|
// The first word of a SHT_GROUP section contains flags. Currently,
|
|
// the standard defines only "GRP_COMDAT" flag for the COMDAT group.
|
|
// An group with the empty flag doesn't define anything; such sections
|
|
// are just skipped.
|
|
if (Entries[0] == 0)
|
|
continue;
|
|
|
|
if (Entries[0] != GRP_COMDAT)
|
|
fatal(toString(this) + ": unsupported SHT_GROUP format");
|
|
|
|
bool IsNew =
|
|
ComdatGroups.try_emplace(CachedHashStringRef(Signature), this).second;
|
|
if (IsNew) {
|
|
if (Config->Relocatable)
|
|
this->Sections[I] = createInputSection(Sec);
|
|
continue;
|
|
}
|
|
|
|
// Otherwise, discard group members.
|
|
for (uint32_t SecIndex : Entries.slice(1)) {
|
|
if (SecIndex >= Size)
|
|
fatal(toString(this) +
|
|
": invalid section index in group: " + Twine(SecIndex));
|
|
this->Sections[SecIndex] = &InputSection::Discarded;
|
|
}
|
|
break;
|
|
}
|
|
case SHT_SYMTAB_SHNDX:
|
|
ShndxTable = CHECK(Obj.getSHNDXTable(Sec, ObjSections), this);
|
|
break;
|
|
case SHT_SYMTAB:
|
|
case SHT_STRTAB:
|
|
case SHT_NULL:
|
|
break;
|
|
default:
|
|
this->Sections[I] = createInputSection(Sec);
|
|
}
|
|
|
|
// .ARM.exidx sections have a reverse dependency on the InputSection they
|
|
// have a SHF_LINK_ORDER dependency, this is identified by the sh_link.
|
|
if (Sec.sh_flags & SHF_LINK_ORDER) {
|
|
InputSectionBase *LinkSec = nullptr;
|
|
if (Sec.sh_link < this->Sections.size())
|
|
LinkSec = this->Sections[Sec.sh_link];
|
|
if (!LinkSec)
|
|
fatal(toString(this) +
|
|
": invalid sh_link index: " + Twine(Sec.sh_link));
|
|
|
|
InputSection *IS = cast<InputSection>(this->Sections[I]);
|
|
LinkSec->DependentSections.push_back(IS);
|
|
if (!isa<InputSection>(LinkSec))
|
|
error("a section " + IS->Name +
|
|
" with SHF_LINK_ORDER should not refer a non-regular "
|
|
"section: " +
|
|
toString(LinkSec));
|
|
}
|
|
}
|
|
}
|
|
|
|
// For ARM only, to set the EF_ARM_ABI_FLOAT_SOFT or EF_ARM_ABI_FLOAT_HARD
|
|
// flag in the ELF Header we need to look at Tag_ABI_VFP_args to find out how
|
|
// the input objects have been compiled.
|
|
static void updateARMVFPArgs(const ARMAttributeParser &Attributes,
|
|
const InputFile *F) {
|
|
if (!Attributes.hasAttribute(ARMBuildAttrs::ABI_VFP_args))
|
|
// If an ABI tag isn't present then it is implicitly given the value of 0
|
|
// which maps to ARMBuildAttrs::BaseAAPCS. However many assembler files,
|
|
// including some in glibc that don't use FP args (and should have value 3)
|
|
// don't have the attribute so we do not consider an implicit value of 0
|
|
// as a clash.
|
|
return;
|
|
|
|
unsigned VFPArgs = Attributes.getAttributeValue(ARMBuildAttrs::ABI_VFP_args);
|
|
ARMVFPArgKind Arg;
|
|
switch (VFPArgs) {
|
|
case ARMBuildAttrs::BaseAAPCS:
|
|
Arg = ARMVFPArgKind::Base;
|
|
break;
|
|
case ARMBuildAttrs::HardFPAAPCS:
|
|
Arg = ARMVFPArgKind::VFP;
|
|
break;
|
|
case ARMBuildAttrs::ToolChainFPPCS:
|
|
// Tool chain specific convention that conforms to neither AAPCS variant.
|
|
Arg = ARMVFPArgKind::ToolChain;
|
|
break;
|
|
case ARMBuildAttrs::CompatibleFPAAPCS:
|
|
// Object compatible with all conventions.
|
|
return;
|
|
default:
|
|
error(toString(F) + ": unknown Tag_ABI_VFP_args value: " + Twine(VFPArgs));
|
|
return;
|
|
}
|
|
// Follow ld.bfd and error if there is a mix of calling conventions.
|
|
if (Config->ARMVFPArgs != Arg && Config->ARMVFPArgs != ARMVFPArgKind::Default)
|
|
error(toString(F) + ": incompatible Tag_ABI_VFP_args");
|
|
else
|
|
Config->ARMVFPArgs = Arg;
|
|
}
|
|
|
|
// The ARM support in lld makes some use of instructions that are not available
|
|
// on all ARM architectures. Namely:
|
|
// - Use of BLX instruction for interworking between ARM and Thumb state.
|
|
// - Use of the extended Thumb branch encoding in relocation.
|
|
// - Use of the MOVT/MOVW instructions in Thumb Thunks.
|
|
// The ARM Attributes section contains information about the architecture chosen
|
|
// at compile time. We follow the convention that if at least one input object
|
|
// is compiled with an architecture that supports these features then lld is
|
|
// permitted to use them.
|
|
static void updateSupportedARMFeatures(const ARMAttributeParser &Attributes) {
|
|
if (!Attributes.hasAttribute(ARMBuildAttrs::CPU_arch))
|
|
return;
|
|
auto Arch = Attributes.getAttributeValue(ARMBuildAttrs::CPU_arch);
|
|
switch (Arch) {
|
|
case ARMBuildAttrs::Pre_v4:
|
|
case ARMBuildAttrs::v4:
|
|
case ARMBuildAttrs::v4T:
|
|
// Architectures prior to v5 do not support BLX instruction
|
|
break;
|
|
case ARMBuildAttrs::v5T:
|
|
case ARMBuildAttrs::v5TE:
|
|
case ARMBuildAttrs::v5TEJ:
|
|
case ARMBuildAttrs::v6:
|
|
case ARMBuildAttrs::v6KZ:
|
|
case ARMBuildAttrs::v6K:
|
|
Config->ARMHasBlx = true;
|
|
// Architectures used in pre-Cortex processors do not support
|
|
// The J1 = 1 J2 = 1 Thumb branch range extension, with the exception
|
|
// of Architecture v6T2 (arm1156t2-s and arm1156t2f-s) that do.
|
|
break;
|
|
default:
|
|
// All other Architectures have BLX and extended branch encoding
|
|
Config->ARMHasBlx = true;
|
|
Config->ARMJ1J2BranchEncoding = true;
|
|
if (Arch != ARMBuildAttrs::v6_M && Arch != ARMBuildAttrs::v6S_M)
|
|
// All Architectures used in Cortex processors with the exception
|
|
// of v6-M and v6S-M have the MOVT and MOVW instructions.
|
|
Config->ARMHasMovtMovw = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
// If a source file is compiled with x86 hardware-assisted call flow control
|
|
// enabled, the generated object file contains feature flags indicating that
|
|
// fact. This function reads the feature flags and returns it.
|
|
//
|
|
// Essentially we want to read a single 32-bit value in this function, but this
|
|
// function is rather complicated because the value is buried deep inside a
|
|
// .note.gnu.property section.
|
|
//
|
|
// The section consists of one or more NOTE records. Each NOTE record consists
|
|
// of zero or more type-length-value fields. We want to find a field of a
|
|
// certain type. It seems a bit too much to just store a 32-bit value, perhaps
|
|
// the ABI is unnecessarily complicated.
|
|
template <class ELFT>
|
|
static uint32_t readAndFeatures(ObjFile<ELFT> *Obj, ArrayRef<uint8_t> Data) {
|
|
using Elf_Nhdr = typename ELFT::Nhdr;
|
|
using Elf_Note = typename ELFT::Note;
|
|
|
|
uint32_t FeaturesSet = 0;
|
|
while (!Data.empty()) {
|
|
// Read one NOTE record.
|
|
if (Data.size() < sizeof(Elf_Nhdr))
|
|
fatal(toString(Obj) + ": .note.gnu.property: section too short");
|
|
|
|
auto *Nhdr = reinterpret_cast<const Elf_Nhdr *>(Data.data());
|
|
if (Data.size() < Nhdr->getSize())
|
|
fatal(toString(Obj) + ": .note.gnu.property: section too short");
|
|
|
|
Elf_Note Note(*Nhdr);
|
|
if (Nhdr->n_type != NT_GNU_PROPERTY_TYPE_0 || Note.getName() != "GNU") {
|
|
Data = Data.slice(Nhdr->getSize());
|
|
continue;
|
|
}
|
|
|
|
// Read a body of a NOTE record, which consists of type-length-value fields.
|
|
ArrayRef<uint8_t> Desc = Note.getDesc();
|
|
while (!Desc.empty()) {
|
|
if (Desc.size() < 8)
|
|
fatal(toString(Obj) + ": .note.gnu.property: section too short");
|
|
|
|
uint32_t Type = read32le(Desc.data());
|
|
uint32_t Size = read32le(Desc.data() + 4);
|
|
|
|
if (Type == GNU_PROPERTY_X86_FEATURE_1_AND) {
|
|
// We found a FEATURE_1_AND field. There may be more than one of these
|
|
// in a .note.gnu.propery section, for a relocatable object we
|
|
// accumulate the bits set.
|
|
FeaturesSet |= read32le(Desc.data() + 8);
|
|
}
|
|
|
|
// On 64-bit, a payload may be followed by a 4-byte padding to make its
|
|
// size a multiple of 8.
|
|
if (ELFT::Is64Bits)
|
|
Size = alignTo(Size, 8);
|
|
|
|
Desc = Desc.slice(Size + 8); // +8 for Type and Size
|
|
}
|
|
|
|
// Go to next NOTE record to look for more FEATURE_1_AND descriptions.
|
|
Data = Data.slice(Nhdr->getSize());
|
|
}
|
|
|
|
return FeaturesSet;
|
|
}
|
|
|
|
template <class ELFT>
|
|
InputSectionBase *ObjFile<ELFT>::getRelocTarget(const Elf_Shdr &Sec) {
|
|
uint32_t Idx = Sec.sh_info;
|
|
if (Idx >= this->Sections.size())
|
|
fatal(toString(this) + ": invalid relocated section index: " + Twine(Idx));
|
|
InputSectionBase *Target = this->Sections[Idx];
|
|
|
|
// Strictly speaking, a relocation section must be included in the
|
|
// group of the section it relocates. However, LLVM 3.3 and earlier
|
|
// would fail to do so, so we gracefully handle that case.
|
|
if (Target == &InputSection::Discarded)
|
|
return nullptr;
|
|
|
|
if (!Target)
|
|
fatal(toString(this) + ": unsupported relocation reference");
|
|
return Target;
|
|
}
|
|
|
|
// Create a regular InputSection class that has the same contents
|
|
// as a given section.
|
|
static InputSection *toRegularSection(MergeInputSection *Sec) {
|
|
return make<InputSection>(Sec->File, Sec->Flags, Sec->Type, Sec->Alignment,
|
|
Sec->data(), Sec->Name);
|
|
}
|
|
|
|
template <class ELFT>
|
|
InputSectionBase *ObjFile<ELFT>::createInputSection(const Elf_Shdr &Sec) {
|
|
StringRef Name = getSectionName(Sec);
|
|
|
|
switch (Sec.sh_type) {
|
|
case SHT_ARM_ATTRIBUTES: {
|
|
if (Config->EMachine != EM_ARM)
|
|
break;
|
|
ARMAttributeParser Attributes;
|
|
ArrayRef<uint8_t> Contents = check(this->getObj().getSectionContents(&Sec));
|
|
Attributes.Parse(Contents, /*isLittle*/ Config->EKind == ELF32LEKind);
|
|
updateSupportedARMFeatures(Attributes);
|
|
updateARMVFPArgs(Attributes, this);
|
|
|
|
// FIXME: Retain the first attribute section we see. The eglibc ARM
|
|
// dynamic loaders require the presence of an attribute section for dlopen
|
|
// to work. In a full implementation we would merge all attribute sections.
|
|
if (In.ARMAttributes == nullptr) {
|
|
In.ARMAttributes = make<InputSection>(*this, Sec, Name);
|
|
return In.ARMAttributes;
|
|
}
|
|
return &InputSection::Discarded;
|
|
}
|
|
case SHT_LLVM_DEPENDENT_LIBRARIES: {
|
|
if (Config->Relocatable)
|
|
break;
|
|
ArrayRef<char> Data =
|
|
CHECK(this->getObj().template getSectionContentsAsArray<char>(&Sec), this);
|
|
if (!Data.empty() && Data.back() != '\0') {
|
|
error(toString(this) +
|
|
": corrupted dependent libraries section (unterminated string): " +
|
|
Name);
|
|
return &InputSection::Discarded;
|
|
}
|
|
for (const char *D = Data.begin(), *E = Data.end(); D < E;) {
|
|
StringRef S(D);
|
|
addDependentLibrary(S, this);
|
|
D += S.size() + 1;
|
|
}
|
|
return &InputSection::Discarded;
|
|
}
|
|
case SHT_RELA:
|
|
case SHT_REL: {
|
|
// Find a relocation target section and associate this section with that.
|
|
// Target may have been discarded if it is in a different section group
|
|
// and the group is discarded, even though it's a violation of the
|
|
// spec. We handle that situation gracefully by discarding dangling
|
|
// relocation sections.
|
|
InputSectionBase *Target = getRelocTarget(Sec);
|
|
if (!Target)
|
|
return nullptr;
|
|
|
|
// This section contains relocation information.
|
|
// If -r is given, we do not interpret or apply relocation
|
|
// but just copy relocation sections to output.
|
|
if (Config->Relocatable) {
|
|
InputSection *RelocSec = make<InputSection>(*this, Sec, Name);
|
|
// We want to add a dependency to target, similar like we do for
|
|
// -emit-relocs below. This is useful for the case when linker script
|
|
// contains the "/DISCARD/". It is perhaps uncommon to use a script with
|
|
// -r, but we faced it in the Linux kernel and have to handle such case
|
|
// and not to crash.
|
|
Target->DependentSections.push_back(RelocSec);
|
|
return RelocSec;
|
|
}
|
|
|
|
if (Target->FirstRelocation)
|
|
fatal(toString(this) +
|
|
": multiple relocation sections to one section are not supported");
|
|
|
|
// ELF spec allows mergeable sections with relocations, but they are
|
|
// rare, and it is in practice hard to merge such sections by contents,
|
|
// because applying relocations at end of linking changes section
|
|
// contents. So, we simply handle such sections as non-mergeable ones.
|
|
// Degrading like this is acceptable because section merging is optional.
|
|
if (auto *MS = dyn_cast<MergeInputSection>(Target)) {
|
|
Target = toRegularSection(MS);
|
|
this->Sections[Sec.sh_info] = Target;
|
|
}
|
|
|
|
if (Sec.sh_type == SHT_RELA) {
|
|
ArrayRef<Elf_Rela> Rels = CHECK(getObj().relas(&Sec), this);
|
|
Target->FirstRelocation = Rels.begin();
|
|
Target->NumRelocations = Rels.size();
|
|
Target->AreRelocsRela = true;
|
|
} else {
|
|
ArrayRef<Elf_Rel> Rels = CHECK(getObj().rels(&Sec), this);
|
|
Target->FirstRelocation = Rels.begin();
|
|
Target->NumRelocations = Rels.size();
|
|
Target->AreRelocsRela = false;
|
|
}
|
|
assert(isUInt<31>(Target->NumRelocations));
|
|
|
|
// Relocation sections processed by the linker are usually removed
|
|
// from the output, so returning `nullptr` for the normal case.
|
|
// However, if -emit-relocs is given, we need to leave them in the output.
|
|
// (Some post link analysis tools need this information.)
|
|
if (Config->EmitRelocs) {
|
|
InputSection *RelocSec = make<InputSection>(*this, Sec, Name);
|
|
// We will not emit relocation section if target was discarded.
|
|
Target->DependentSections.push_back(RelocSec);
|
|
return RelocSec;
|
|
}
|
|
return nullptr;
|
|
}
|
|
}
|
|
|
|
// The GNU linker uses .note.GNU-stack section as a marker indicating
|
|
// that the code in the object file does not expect that the stack is
|
|
// executable (in terms of NX bit). If all input files have the marker,
|
|
// the GNU linker adds a PT_GNU_STACK segment to tells the loader to
|
|
// make the stack non-executable. Most object files have this section as
|
|
// of 2017.
|
|
//
|
|
// But making the stack non-executable is a norm today for security
|
|
// reasons. Failure to do so may result in a serious security issue.
|
|
// Therefore, we make LLD always add PT_GNU_STACK unless it is
|
|
// explicitly told to do otherwise (by -z execstack). Because the stack
|
|
// executable-ness is controlled solely by command line options,
|
|
// .note.GNU-stack sections are simply ignored.
|
|
if (Name == ".note.GNU-stack")
|
|
return &InputSection::Discarded;
|
|
|
|
// If an object file is compatible with Intel Control-Flow Enforcement
|
|
// Technology (CET), it has a .note.gnu.property section containing the
|
|
// GNU_PROPERTY_X86_FEATURE_1_IBT flag. Read a bitmap containing the flag.
|
|
//
|
|
// Since we merge bitmaps from multiple object files to create a new
|
|
// .note.gnu.property containing a single AND'ed bitmap, we discard an input
|
|
// file's .note.gnu.property section.
|
|
if (Name == ".note.gnu.property") {
|
|
ArrayRef<uint8_t> Contents = check(this->getObj().getSectionContents(&Sec));
|
|
this->AndFeatures = readAndFeatures(this, Contents);
|
|
return &InputSection::Discarded;
|
|
}
|
|
|
|
// Split stacks is a feature to support a discontiguous stack,
|
|
// commonly used in the programming language Go. For the details,
|
|
// see https://gcc.gnu.org/wiki/SplitStacks. An object file compiled
|
|
// for split stack will include a .note.GNU-split-stack section.
|
|
if (Name == ".note.GNU-split-stack") {
|
|
if (Config->Relocatable) {
|
|
error("cannot mix split-stack and non-split-stack in a relocatable link");
|
|
return &InputSection::Discarded;
|
|
}
|
|
this->SplitStack = true;
|
|
return &InputSection::Discarded;
|
|
}
|
|
|
|
// An object file cmpiled for split stack, but where some of the
|
|
// functions were compiled with the no_split_stack_attribute will
|
|
// include a .note.GNU-no-split-stack section.
|
|
if (Name == ".note.GNU-no-split-stack") {
|
|
this->SomeNoSplitStack = true;
|
|
return &InputSection::Discarded;
|
|
}
|
|
|
|
// The linkonce feature is a sort of proto-comdat. Some glibc i386 object
|
|
// files contain definitions of symbol "__x86.get_pc_thunk.bx" in linkonce
|
|
// sections. Drop those sections to avoid duplicate symbol errors.
|
|
// FIXME: This is glibc PR20543, we should remove this hack once that has been
|
|
// fixed for a while.
|
|
if (Name == ".gnu.linkonce.t.__x86.get_pc_thunk.bx" ||
|
|
Name == ".gnu.linkonce.t.__i686.get_pc_thunk.bx")
|
|
return &InputSection::Discarded;
|
|
|
|
// If we are creating a new .build-id section, strip existing .build-id
|
|
// sections so that the output won't have more than one .build-id.
|
|
// This is not usually a problem because input object files normally don't
|
|
// have .build-id sections, but you can create such files by
|
|
// "ld.{bfd,gold,lld} -r --build-id", and we want to guard against it.
|
|
if (Name == ".note.gnu.build-id" && Config->BuildId != BuildIdKind::None)
|
|
return &InputSection::Discarded;
|
|
|
|
// The linker merges EH (exception handling) frames and creates a
|
|
// .eh_frame_hdr section for runtime. So we handle them with a special
|
|
// class. For relocatable outputs, they are just passed through.
|
|
if (Name == ".eh_frame" && !Config->Relocatable)
|
|
return make<EhInputSection>(*this, Sec, Name);
|
|
|
|
if (shouldMerge(Sec))
|
|
return make<MergeInputSection>(*this, Sec, Name);
|
|
return make<InputSection>(*this, Sec, Name);
|
|
}
|
|
|
|
template <class ELFT>
|
|
StringRef ObjFile<ELFT>::getSectionName(const Elf_Shdr &Sec) {
|
|
return CHECK(getObj().getSectionName(&Sec, SectionStringTable), this);
|
|
}
|
|
|
|
// Initialize this->Symbols. this->Symbols is a parallel array as
|
|
// its corresponding ELF symbol table.
|
|
template <class ELFT> void ObjFile<ELFT>::initializeSymbols() {
|
|
ArrayRef<Elf_Sym> ESyms = this->getELFSyms<ELFT>();
|
|
this->Symbols.resize(ESyms.size());
|
|
|
|
// Our symbol table may have already been partially initialized
|
|
// because of LazyObjFile.
|
|
for (size_t I = 0, End = ESyms.size(); I != End; ++I)
|
|
if (!this->Symbols[I] && ESyms[I].getBinding() != STB_LOCAL)
|
|
this->Symbols[I] =
|
|
Symtab->insert(CHECK(ESyms[I].getName(this->StringTable), this));
|
|
|
|
// Fill this->Symbols. A symbol is either local or global.
|
|
for (size_t I = 0, End = ESyms.size(); I != End; ++I) {
|
|
const Elf_Sym &ESym = ESyms[I];
|
|
|
|
// Read symbol attributes.
|
|
uint32_t SecIdx = getSectionIndex(ESym);
|
|
if (SecIdx >= this->Sections.size())
|
|
fatal(toString(this) + ": invalid section index: " + Twine(SecIdx));
|
|
|
|
InputSectionBase *Sec = this->Sections[SecIdx];
|
|
uint8_t Binding = ESym.getBinding();
|
|
uint8_t StOther = ESym.st_other;
|
|
uint8_t Type = ESym.getType();
|
|
uint64_t Value = ESym.st_value;
|
|
uint64_t Size = ESym.st_size;
|
|
StringRefZ Name = this->StringTable.data() + ESym.st_name;
|
|
|
|
// Handle local symbols. Local symbols are not added to the symbol
|
|
// table because they are not visible from other object files. We
|
|
// allocate symbol instances and add their pointers to Symbols.
|
|
if (Binding == STB_LOCAL) {
|
|
if (ESym.getType() == STT_FILE)
|
|
SourceFile = CHECK(ESym.getName(this->StringTable), this);
|
|
|
|
if (this->StringTable.size() <= ESym.st_name)
|
|
fatal(toString(this) + ": invalid symbol name offset");
|
|
|
|
if (ESym.st_shndx == SHN_UNDEF)
|
|
this->Symbols[I] = make<Undefined>(this, Name, Binding, StOther, Type);
|
|
else if (Sec == &InputSection::Discarded)
|
|
this->Symbols[I] = make<Undefined>(this, Name, Binding, StOther, Type,
|
|
/*DiscardedSecIdx=*/SecIdx);
|
|
else
|
|
this->Symbols[I] =
|
|
make<Defined>(this, Name, Binding, StOther, Type, Value, Size, Sec);
|
|
continue;
|
|
}
|
|
|
|
// Handle global undefined symbols.
|
|
if (ESym.st_shndx == SHN_UNDEF) {
|
|
this->Symbols[I]->resolve(Undefined{this, Name, Binding, StOther, Type});
|
|
continue;
|
|
}
|
|
|
|
// Handle global common symbols.
|
|
if (ESym.st_shndx == SHN_COMMON) {
|
|
if (Value == 0 || Value >= UINT32_MAX)
|
|
fatal(toString(this) + ": common symbol '" + StringRef(Name.Data) +
|
|
"' has invalid alignment: " + Twine(Value));
|
|
this->Symbols[I]->resolve(
|
|
CommonSymbol{this, Name, Binding, StOther, Type, Value, Size});
|
|
continue;
|
|
}
|
|
|
|
// If a defined symbol is in a discarded section, handle it as if it
|
|
// were an undefined symbol. Such symbol doesn't comply with the
|
|
// standard, but in practice, a .eh_frame often directly refer
|
|
// COMDAT member sections, and if a comdat group is discarded, some
|
|
// defined symbol in a .eh_frame becomes dangling symbols.
|
|
if (Sec == &InputSection::Discarded) {
|
|
this->Symbols[I]->resolve(
|
|
Undefined{this, Name, Binding, StOther, Type, SecIdx});
|
|
continue;
|
|
}
|
|
|
|
// Handle global defined symbols.
|
|
if (Binding == STB_GLOBAL || Binding == STB_WEAK ||
|
|
Binding == STB_GNU_UNIQUE) {
|
|
this->Symbols[I]->resolve(
|
|
Defined{this, Name, Binding, StOther, Type, Value, Size, Sec});
|
|
continue;
|
|
}
|
|
|
|
fatal(toString(this) + ": unexpected binding: " + Twine((int)Binding));
|
|
}
|
|
}
|
|
|
|
ArchiveFile::ArchiveFile(std::unique_ptr<Archive> &&File)
|
|
: InputFile(ArchiveKind, File->getMemoryBufferRef()),
|
|
File(std::move(File)) {}
|
|
|
|
void ArchiveFile::parse() {
|
|
for (const Archive::Symbol &Sym : File->symbols())
|
|
Symtab->addSymbol(LazyArchive{*this, Sym});
|
|
}
|
|
|
|
// Returns a buffer pointing to a member file containing a given symbol.
|
|
void ArchiveFile::fetch(const Archive::Symbol &Sym) {
|
|
Archive::Child C =
|
|
CHECK(Sym.getMember(), toString(this) +
|
|
": could not get the member for symbol " +
|
|
Sym.getName());
|
|
|
|
if (!Seen.insert(C.getChildOffset()).second)
|
|
return;
|
|
|
|
MemoryBufferRef MB =
|
|
CHECK(C.getMemoryBufferRef(),
|
|
toString(this) +
|
|
": could not get the buffer for the member defining symbol " +
|
|
Sym.getName());
|
|
|
|
if (Tar && C.getParent()->isThin())
|
|
Tar->append(relativeToRoot(CHECK(C.getFullName(), this)), MB.getBuffer());
|
|
|
|
InputFile *File = createObjectFile(
|
|
MB, getName(), C.getParent()->isThin() ? 0 : C.getChildOffset());
|
|
File->GroupId = GroupId;
|
|
parseFile(File);
|
|
}
|
|
|
|
unsigned SharedFile::VernauxNum;
|
|
|
|
// Parse the version definitions in the object file if present, and return a
|
|
// vector whose nth element contains a pointer to the Elf_Verdef for version
|
|
// identifier n. Version identifiers that are not definitions map to nullptr.
|
|
template <typename ELFT>
|
|
static std::vector<const void *> parseVerdefs(const uint8_t *Base,
|
|
const typename ELFT::Shdr *Sec) {
|
|
if (!Sec)
|
|
return {};
|
|
|
|
// We cannot determine the largest verdef identifier without inspecting
|
|
// every Elf_Verdef, but both bfd and gold assign verdef identifiers
|
|
// sequentially starting from 1, so we predict that the largest identifier
|
|
// will be VerdefCount.
|
|
unsigned VerdefCount = Sec->sh_info;
|
|
std::vector<const void *> Verdefs(VerdefCount + 1);
|
|
|
|
// Build the Verdefs array by following the chain of Elf_Verdef objects
|
|
// from the start of the .gnu.version_d section.
|
|
const uint8_t *Verdef = Base + Sec->sh_offset;
|
|
for (unsigned I = 0; I != VerdefCount; ++I) {
|
|
auto *CurVerdef = reinterpret_cast<const typename ELFT::Verdef *>(Verdef);
|
|
Verdef += CurVerdef->vd_next;
|
|
unsigned VerdefIndex = CurVerdef->vd_ndx;
|
|
Verdefs.resize(VerdefIndex + 1);
|
|
Verdefs[VerdefIndex] = CurVerdef;
|
|
}
|
|
return Verdefs;
|
|
}
|
|
|
|
// We do not usually care about alignments of data in shared object
|
|
// files because the loader takes care of it. However, if we promote a
|
|
// DSO symbol to point to .bss due to copy relocation, we need to keep
|
|
// the original alignment requirements. We infer it in this function.
|
|
template <typename ELFT>
|
|
static uint64_t getAlignment(ArrayRef<typename ELFT::Shdr> Sections,
|
|
const typename ELFT::Sym &Sym) {
|
|
uint64_t Ret = UINT64_MAX;
|
|
if (Sym.st_value)
|
|
Ret = 1ULL << countTrailingZeros((uint64_t)Sym.st_value);
|
|
if (0 < Sym.st_shndx && Sym.st_shndx < Sections.size())
|
|
Ret = std::min<uint64_t>(Ret, Sections[Sym.st_shndx].sh_addralign);
|
|
return (Ret > UINT32_MAX) ? 0 : Ret;
|
|
}
|
|
|
|
// Fully parse the shared object file.
|
|
//
|
|
// This function parses symbol versions. If a DSO has version information,
|
|
// the file has a ".gnu.version_d" section which contains symbol version
|
|
// definitions. Each symbol is associated to one version through a table in
|
|
// ".gnu.version" section. That table is a parallel array for the symbol
|
|
// table, and each table entry contains an index in ".gnu.version_d".
|
|
//
|
|
// The special index 0 is reserved for VERF_NDX_LOCAL and 1 is for
|
|
// VER_NDX_GLOBAL. There's no table entry for these special versions in
|
|
// ".gnu.version_d".
|
|
//
|
|
// The file format for symbol versioning is perhaps a bit more complicated
|
|
// than necessary, but you can easily understand the code if you wrap your
|
|
// head around the data structure described above.
|
|
template <class ELFT> void SharedFile::parse() {
|
|
using Elf_Dyn = typename ELFT::Dyn;
|
|
using Elf_Shdr = typename ELFT::Shdr;
|
|
using Elf_Sym = typename ELFT::Sym;
|
|
using Elf_Verdef = typename ELFT::Verdef;
|
|
using Elf_Versym = typename ELFT::Versym;
|
|
|
|
ArrayRef<Elf_Dyn> DynamicTags;
|
|
const ELFFile<ELFT> Obj = this->getObj<ELFT>();
|
|
ArrayRef<Elf_Shdr> Sections = CHECK(Obj.sections(), this);
|
|
|
|
const Elf_Shdr *VersymSec = nullptr;
|
|
const Elf_Shdr *VerdefSec = nullptr;
|
|
|
|
// Search for .dynsym, .dynamic, .symtab, .gnu.version and .gnu.version_d.
|
|
for (const Elf_Shdr &Sec : Sections) {
|
|
switch (Sec.sh_type) {
|
|
default:
|
|
continue;
|
|
case SHT_DYNAMIC:
|
|
DynamicTags =
|
|
CHECK(Obj.template getSectionContentsAsArray<Elf_Dyn>(&Sec), this);
|
|
break;
|
|
case SHT_GNU_versym:
|
|
VersymSec = &Sec;
|
|
break;
|
|
case SHT_GNU_verdef:
|
|
VerdefSec = &Sec;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (VersymSec && NumELFSyms == 0) {
|
|
error("SHT_GNU_versym should be associated with symbol table");
|
|
return;
|
|
}
|
|
|
|
// Search for a DT_SONAME tag to initialize this->SoName.
|
|
for (const Elf_Dyn &Dyn : DynamicTags) {
|
|
if (Dyn.d_tag == DT_NEEDED) {
|
|
uint64_t Val = Dyn.getVal();
|
|
if (Val >= this->StringTable.size())
|
|
fatal(toString(this) + ": invalid DT_NEEDED entry");
|
|
DtNeeded.push_back(this->StringTable.data() + Val);
|
|
} else if (Dyn.d_tag == DT_SONAME) {
|
|
uint64_t Val = Dyn.getVal();
|
|
if (Val >= this->StringTable.size())
|
|
fatal(toString(this) + ": invalid DT_SONAME entry");
|
|
SoName = this->StringTable.data() + Val;
|
|
}
|
|
}
|
|
|
|
// DSOs are uniquified not by filename but by soname.
|
|
DenseMap<StringRef, SharedFile *>::iterator It;
|
|
bool WasInserted;
|
|
std::tie(It, WasInserted) = Symtab->SoNames.try_emplace(SoName, this);
|
|
|
|
// If a DSO appears more than once on the command line with and without
|
|
// --as-needed, --no-as-needed takes precedence over --as-needed because a
|
|
// user can add an extra DSO with --no-as-needed to force it to be added to
|
|
// the dependency list.
|
|
It->second->IsNeeded |= IsNeeded;
|
|
if (!WasInserted)
|
|
return;
|
|
|
|
SharedFiles.push_back(this);
|
|
|
|
Verdefs = parseVerdefs<ELFT>(Obj.base(), VerdefSec);
|
|
|
|
// Parse ".gnu.version" section which is a parallel array for the symbol
|
|
// table. If a given file doesn't have a ".gnu.version" section, we use
|
|
// VER_NDX_GLOBAL.
|
|
size_t Size = NumELFSyms - FirstGlobal;
|
|
std::vector<uint32_t> Versyms(Size, VER_NDX_GLOBAL);
|
|
if (VersymSec) {
|
|
ArrayRef<Elf_Versym> Versym =
|
|
CHECK(Obj.template getSectionContentsAsArray<Elf_Versym>(VersymSec),
|
|
this)
|
|
.slice(FirstGlobal);
|
|
for (size_t I = 0; I < Size; ++I)
|
|
Versyms[I] = Versym[I].vs_index;
|
|
}
|
|
|
|
// System libraries can have a lot of symbols with versions. Using a
|
|
// fixed buffer for computing the versions name (foo@ver) can save a
|
|
// lot of allocations.
|
|
SmallString<0> VersionedNameBuffer;
|
|
|
|
// Add symbols to the symbol table.
|
|
ArrayRef<Elf_Sym> Syms = this->getGlobalELFSyms<ELFT>();
|
|
for (size_t I = 0; I < Syms.size(); ++I) {
|
|
const Elf_Sym &Sym = Syms[I];
|
|
|
|
// ELF spec requires that all local symbols precede weak or global
|
|
// symbols in each symbol table, and the index of first non-local symbol
|
|
// is stored to sh_info. If a local symbol appears after some non-local
|
|
// symbol, that's a violation of the spec.
|
|
StringRef Name = CHECK(Sym.getName(this->StringTable), this);
|
|
if (Sym.getBinding() == STB_LOCAL) {
|
|
warn("found local symbol '" + Name +
|
|
"' in global part of symbol table in file " + toString(this));
|
|
continue;
|
|
}
|
|
|
|
if (Sym.isUndefined()) {
|
|
Symbol *S = Symtab->addSymbol(
|
|
Undefined{this, Name, Sym.getBinding(), Sym.st_other, Sym.getType()});
|
|
S->ExportDynamic = true;
|
|
continue;
|
|
}
|
|
|
|
// MIPS BFD linker puts _gp_disp symbol into DSO files and incorrectly
|
|
// assigns VER_NDX_LOCAL to this section global symbol. Here is a
|
|
// workaround for this bug.
|
|
uint32_t Idx = Versyms[I] & ~VERSYM_HIDDEN;
|
|
if (Config->EMachine == EM_MIPS && Idx == VER_NDX_LOCAL &&
|
|
Name == "_gp_disp")
|
|
continue;
|
|
|
|
uint32_t Alignment = getAlignment<ELFT>(Sections, Sym);
|
|
if (!(Versyms[I] & VERSYM_HIDDEN)) {
|
|
Symtab->addSymbol(SharedSymbol{*this, Name, Sym.getBinding(),
|
|
Sym.st_other, Sym.getType(), Sym.st_value,
|
|
Sym.st_size, Alignment, Idx});
|
|
}
|
|
|
|
// Also add the symbol with the versioned name to handle undefined symbols
|
|
// with explicit versions.
|
|
if (Idx == VER_NDX_GLOBAL)
|
|
continue;
|
|
|
|
if (Idx >= Verdefs.size() || Idx == VER_NDX_LOCAL) {
|
|
error("corrupt input file: version definition index " + Twine(Idx) +
|
|
" for symbol " + Name + " is out of bounds\n>>> defined in " +
|
|
toString(this));
|
|
continue;
|
|
}
|
|
|
|
StringRef VerName =
|
|
this->StringTable.data() +
|
|
reinterpret_cast<const Elf_Verdef *>(Verdefs[Idx])->getAux()->vda_name;
|
|
VersionedNameBuffer.clear();
|
|
Name = (Name + "@" + VerName).toStringRef(VersionedNameBuffer);
|
|
Symtab->addSymbol(SharedSymbol{*this, Saver.save(Name), Sym.getBinding(),
|
|
Sym.st_other, Sym.getType(), Sym.st_value,
|
|
Sym.st_size, Alignment, Idx});
|
|
}
|
|
}
|
|
|
|
static ELFKind getBitcodeELFKind(const Triple &T) {
|
|
if (T.isLittleEndian())
|
|
return T.isArch64Bit() ? ELF64LEKind : ELF32LEKind;
|
|
return T.isArch64Bit() ? ELF64BEKind : ELF32BEKind;
|
|
}
|
|
|
|
static uint8_t getBitcodeMachineKind(StringRef Path, const Triple &T) {
|
|
switch (T.getArch()) {
|
|
case Triple::aarch64:
|
|
return EM_AARCH64;
|
|
case Triple::amdgcn:
|
|
case Triple::r600:
|
|
return EM_AMDGPU;
|
|
case Triple::arm:
|
|
case Triple::thumb:
|
|
return EM_ARM;
|
|
case Triple::avr:
|
|
return EM_AVR;
|
|
case Triple::mips:
|
|
case Triple::mipsel:
|
|
case Triple::mips64:
|
|
case Triple::mips64el:
|
|
return EM_MIPS;
|
|
case Triple::msp430:
|
|
return EM_MSP430;
|
|
case Triple::ppc:
|
|
return EM_PPC;
|
|
case Triple::ppc64:
|
|
case Triple::ppc64le:
|
|
return EM_PPC64;
|
|
case Triple::x86:
|
|
return T.isOSIAMCU() ? EM_IAMCU : EM_386;
|
|
case Triple::x86_64:
|
|
return EM_X86_64;
|
|
default:
|
|
error(Path + ": could not infer e_machine from bitcode target triple " +
|
|
T.str());
|
|
return EM_NONE;
|
|
}
|
|
}
|
|
|
|
BitcodeFile::BitcodeFile(MemoryBufferRef MB, StringRef ArchiveName,
|
|
uint64_t OffsetInArchive)
|
|
: InputFile(BitcodeKind, MB) {
|
|
this->ArchiveName = ArchiveName;
|
|
|
|
std::string Path = MB.getBufferIdentifier().str();
|
|
if (Config->ThinLTOIndexOnly)
|
|
Path = replaceThinLTOSuffix(MB.getBufferIdentifier());
|
|
|
|
// ThinLTO assumes that all MemoryBufferRefs given to it have a unique
|
|
// name. If two archives define two members with the same name, this
|
|
// causes a collision which result in only one of the objects being taken
|
|
// into consideration at LTO time (which very likely causes undefined
|
|
// symbols later in the link stage). So we append file offset to make
|
|
// filename unique.
|
|
StringRef Name = ArchiveName.empty()
|
|
? Saver.save(Path)
|
|
: Saver.save(ArchiveName + "(" + Path + " at " +
|
|
utostr(OffsetInArchive) + ")");
|
|
MemoryBufferRef MBRef(MB.getBuffer(), Name);
|
|
|
|
Obj = CHECK(lto::InputFile::create(MBRef), this);
|
|
|
|
Triple T(Obj->getTargetTriple());
|
|
EKind = getBitcodeELFKind(T);
|
|
EMachine = getBitcodeMachineKind(MB.getBufferIdentifier(), T);
|
|
}
|
|
|
|
static uint8_t mapVisibility(GlobalValue::VisibilityTypes GvVisibility) {
|
|
switch (GvVisibility) {
|
|
case GlobalValue::DefaultVisibility:
|
|
return STV_DEFAULT;
|
|
case GlobalValue::HiddenVisibility:
|
|
return STV_HIDDEN;
|
|
case GlobalValue::ProtectedVisibility:
|
|
return STV_PROTECTED;
|
|
}
|
|
llvm_unreachable("unknown visibility");
|
|
}
|
|
|
|
template <class ELFT>
|
|
static Symbol *createBitcodeSymbol(const std::vector<bool> &KeptComdats,
|
|
const lto::InputFile::Symbol &ObjSym,
|
|
BitcodeFile &F) {
|
|
StringRef Name = Saver.save(ObjSym.getName());
|
|
uint8_t Binding = ObjSym.isWeak() ? STB_WEAK : STB_GLOBAL;
|
|
uint8_t Type = ObjSym.isTLS() ? STT_TLS : STT_NOTYPE;
|
|
uint8_t Visibility = mapVisibility(ObjSym.getVisibility());
|
|
bool CanOmitFromDynSym = ObjSym.canBeOmittedFromSymbolTable();
|
|
|
|
int C = ObjSym.getComdatIndex();
|
|
if (ObjSym.isUndefined() || (C != -1 && !KeptComdats[C])) {
|
|
Undefined New(&F, Name, Binding, Visibility, Type);
|
|
if (CanOmitFromDynSym)
|
|
New.ExportDynamic = false;
|
|
return Symtab->addSymbol(New);
|
|
}
|
|
|
|
if (ObjSym.isCommon())
|
|
return Symtab->addSymbol(
|
|
CommonSymbol{&F, Name, Binding, Visibility, STT_OBJECT,
|
|
ObjSym.getCommonAlignment(), ObjSym.getCommonSize()});
|
|
|
|
Defined New(&F, Name, Binding, Visibility, Type, 0, 0, nullptr);
|
|
if (CanOmitFromDynSym)
|
|
New.ExportDynamic = false;
|
|
return Symtab->addSymbol(New);
|
|
}
|
|
|
|
template <class ELFT>
|
|
void BitcodeFile::parse(
|
|
DenseMap<CachedHashStringRef, const InputFile *> &ComdatGroups) {
|
|
std::vector<bool> KeptComdats;
|
|
for (StringRef S : Obj->getComdatTable())
|
|
KeptComdats.push_back(
|
|
ComdatGroups.try_emplace(CachedHashStringRef(S), this).second);
|
|
|
|
for (const lto::InputFile::Symbol &ObjSym : Obj->symbols())
|
|
Symbols.push_back(createBitcodeSymbol<ELFT>(KeptComdats, ObjSym, *this));
|
|
|
|
for (auto L : Obj->getDependentLibraries())
|
|
addDependentLibrary(L, this);
|
|
}
|
|
|
|
void BinaryFile::parse() {
|
|
ArrayRef<uint8_t> Data = arrayRefFromStringRef(MB.getBuffer());
|
|
auto *Section = make<InputSection>(this, SHF_ALLOC | SHF_WRITE, SHT_PROGBITS,
|
|
8, Data, ".data");
|
|
Sections.push_back(Section);
|
|
|
|
// For each input file foo that is embedded to a result as a binary
|
|
// blob, we define _binary_foo_{start,end,size} symbols, so that
|
|
// user programs can access blobs by name. Non-alphanumeric
|
|
// characters in a filename are replaced with underscore.
|
|
std::string S = "_binary_" + MB.getBufferIdentifier().str();
|
|
for (size_t I = 0; I < S.size(); ++I)
|
|
if (!isAlnum(S[I]))
|
|
S[I] = '_';
|
|
|
|
Symtab->addSymbol(Defined{nullptr, Saver.save(S + "_start"), STB_GLOBAL,
|
|
STV_DEFAULT, STT_OBJECT, 0, 0, Section});
|
|
Symtab->addSymbol(Defined{nullptr, Saver.save(S + "_end"), STB_GLOBAL,
|
|
STV_DEFAULT, STT_OBJECT, Data.size(), 0, Section});
|
|
Symtab->addSymbol(Defined{nullptr, Saver.save(S + "_size"), STB_GLOBAL,
|
|
STV_DEFAULT, STT_OBJECT, Data.size(), 0, nullptr});
|
|
}
|
|
|
|
InputFile *elf::createObjectFile(MemoryBufferRef MB, StringRef ArchiveName,
|
|
uint64_t OffsetInArchive) {
|
|
if (isBitcode(MB))
|
|
return make<BitcodeFile>(MB, ArchiveName, OffsetInArchive);
|
|
|
|
switch (getELFKind(MB, ArchiveName)) {
|
|
case ELF32LEKind:
|
|
return make<ObjFile<ELF32LE>>(MB, ArchiveName);
|
|
case ELF32BEKind:
|
|
return make<ObjFile<ELF32BE>>(MB, ArchiveName);
|
|
case ELF64LEKind:
|
|
return make<ObjFile<ELF64LE>>(MB, ArchiveName);
|
|
case ELF64BEKind:
|
|
return make<ObjFile<ELF64BE>>(MB, ArchiveName);
|
|
default:
|
|
llvm_unreachable("getELFKind");
|
|
}
|
|
}
|
|
|
|
void LazyObjFile::fetch() {
|
|
if (MB.getBuffer().empty())
|
|
return;
|
|
|
|
InputFile *File = createObjectFile(MB, ArchiveName, OffsetInArchive);
|
|
File->GroupId = GroupId;
|
|
|
|
MB = {};
|
|
|
|
// Copy symbol vector so that the new InputFile doesn't have to
|
|
// insert the same defined symbols to the symbol table again.
|
|
File->Symbols = std::move(Symbols);
|
|
|
|
parseFile(File);
|
|
}
|
|
|
|
template <class ELFT> void LazyObjFile::parse() {
|
|
using Elf_Sym = typename ELFT::Sym;
|
|
|
|
// A lazy object file wraps either a bitcode file or an ELF file.
|
|
if (isBitcode(this->MB)) {
|
|
std::unique_ptr<lto::InputFile> Obj =
|
|
CHECK(lto::InputFile::create(this->MB), this);
|
|
for (const lto::InputFile::Symbol &Sym : Obj->symbols()) {
|
|
if (Sym.isUndefined())
|
|
continue;
|
|
Symtab->addSymbol(LazyObject{*this, Saver.save(Sym.getName())});
|
|
}
|
|
return;
|
|
}
|
|
|
|
if (getELFKind(this->MB, ArchiveName) != Config->EKind) {
|
|
error("incompatible file: " + this->MB.getBufferIdentifier());
|
|
return;
|
|
}
|
|
|
|
// Find a symbol table.
|
|
ELFFile<ELFT> Obj = check(ELFFile<ELFT>::create(MB.getBuffer()));
|
|
ArrayRef<typename ELFT::Shdr> Sections = CHECK(Obj.sections(), this);
|
|
|
|
for (const typename ELFT::Shdr &Sec : Sections) {
|
|
if (Sec.sh_type != SHT_SYMTAB)
|
|
continue;
|
|
|
|
// A symbol table is found.
|
|
ArrayRef<Elf_Sym> ESyms = CHECK(Obj.symbols(&Sec), this);
|
|
uint32_t FirstGlobal = Sec.sh_info;
|
|
StringRef Strtab = CHECK(Obj.getStringTableForSymtab(Sec, Sections), this);
|
|
this->Symbols.resize(ESyms.size());
|
|
|
|
// Get existing symbols or insert placeholder symbols.
|
|
for (size_t I = FirstGlobal, End = ESyms.size(); I != End; ++I)
|
|
if (ESyms[I].st_shndx != SHN_UNDEF)
|
|
this->Symbols[I] = Symtab->insert(CHECK(ESyms[I].getName(Strtab), this));
|
|
|
|
// Replace existing symbols with LazyObject symbols.
|
|
//
|
|
// resolve() may trigger this->fetch() if an existing symbol is an
|
|
// undefined symbol. If that happens, this LazyObjFile has served
|
|
// its purpose, and we can exit from the loop early.
|
|
for (Symbol *Sym : this->Symbols) {
|
|
if (!Sym)
|
|
continue;
|
|
Sym->resolve(LazyObject{*this, Sym->getName()});
|
|
|
|
// MemoryBuffer is emptied if this file is instantiated as ObjFile.
|
|
if (MB.getBuffer().empty())
|
|
return;
|
|
}
|
|
return;
|
|
}
|
|
}
|
|
|
|
std::string elf::replaceThinLTOSuffix(StringRef Path) {
|
|
StringRef Suffix = Config->ThinLTOObjectSuffixReplace.first;
|
|
StringRef Repl = Config->ThinLTOObjectSuffixReplace.second;
|
|
|
|
if (Path.consume_back(Suffix))
|
|
return (Path + Repl).str();
|
|
return Path;
|
|
}
|
|
|
|
template void
|
|
BitcodeFile::parse<ELF32LE>(DenseMap<CachedHashStringRef, const InputFile *> &);
|
|
template void
|
|
BitcodeFile::parse<ELF32BE>(DenseMap<CachedHashStringRef, const InputFile *> &);
|
|
template void
|
|
BitcodeFile::parse<ELF64LE>(DenseMap<CachedHashStringRef, const InputFile *> &);
|
|
template void
|
|
BitcodeFile::parse<ELF64BE>(DenseMap<CachedHashStringRef, const InputFile *> &);
|
|
|
|
template void LazyObjFile::parse<ELF32LE>();
|
|
template void LazyObjFile::parse<ELF32BE>();
|
|
template void LazyObjFile::parse<ELF64LE>();
|
|
template void LazyObjFile::parse<ELF64BE>();
|
|
|
|
template class elf::ObjFile<ELF32LE>;
|
|
template class elf::ObjFile<ELF32BE>;
|
|
template class elf::ObjFile<ELF64LE>;
|
|
template class elf::ObjFile<ELF64BE>;
|
|
|
|
template void SharedFile::parse<ELF32LE>();
|
|
template void SharedFile::parse<ELF32BE>();
|
|
template void SharedFile::parse<ELF64LE>();
|
|
template void SharedFile::parse<ELF64BE>();
|