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|
//===- lib/ReaderWriter/ELF/ELFLinkingContext.cpp -------------------------===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "lld/ReaderWriter/ELFLinkingContext.h"
#include "ArrayOrderPass.h"
#include "ELFFile.h"
#include "TargetHandler.h"
#include "Targets.h"
#include "lld/Core/Instrumentation.h"
#include "lld/Passes/LayoutPass.h"
#include "lld/Passes/RoundTripYAMLPass.h"
#include "llvm/ADT/Triple.h"
#include "llvm/Support/ELF.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Path.h"
namespace lld {
class CommandLineUndefinedAtom : public SimpleUndefinedAtom {
public:
CommandLineUndefinedAtom(const File &f, StringRef name)
: SimpleUndefinedAtom(f, name) {}
virtual CanBeNull canBeNull() const {
return CanBeNull::canBeNullAtBuildtime;
}
};
ELFLinkingContext::ELFLinkingContext(
llvm::Triple triple, std::unique_ptr<TargetHandlerBase> targetHandler)
: _outputELFType(elf::ET_EXEC), _triple(triple),
_targetHandler(std::move(targetHandler)), _baseAddress(0),
_isStaticExecutable(false), _noInhibitExec(false),
_mergeCommonStrings(false), _runLayoutPass(true),
_useShlibUndefines(true), _dynamicLinkerArg(false),
_noAllowDynamicLibraries(false), _outputMagic(OutputMagic::DEFAULT),
_sysrootPath("") {}
bool ELFLinkingContext::is64Bits() const { return getTriple().isArch64Bit(); }
bool ELFLinkingContext::isLittleEndian() const {
// TODO: Do this properly. It is not defined purely by arch.
return true;
}
void ELFLinkingContext::addPasses(PassManager &pm) {
if (_runLayoutPass)
pm.add(std::unique_ptr<Pass>(new LayoutPass()));
pm.add(std::unique_ptr<Pass>(new elf::ArrayOrderPass()));
}
uint16_t ELFLinkingContext::getOutputMachine() const {
switch (getTriple().getArch()) {
case llvm::Triple::x86:
return llvm::ELF::EM_386;
case llvm::Triple::x86_64:
return llvm::ELF::EM_X86_64;
case llvm::Triple::hexagon:
return llvm::ELF::EM_HEXAGON;
case llvm::Triple::mipsel:
return llvm::ELF::EM_MIPS;
case llvm::Triple::ppc:
return llvm::ELF::EM_PPC;
default:
llvm_unreachable("Unhandled arch");
}
}
StringRef ELFLinkingContext::entrySymbolName() const {
if (_outputELFType == elf::ET_EXEC && _entrySymbolName.empty())
return "_start";
return _entrySymbolName;
}
bool ELFLinkingContext::validateImpl(raw_ostream &diagnostics) {
switch (outputFileType()) {
case LinkingContext::OutputFileType::YAML:
_writer = createWriterYAML(*this);
break;
case LinkingContext::OutputFileType::Native:
llvm_unreachable("Unimplemented");
break;
default:
_writer = createWriterELF(this->targetHandler());
break;
}
return true;
}
bool ELFLinkingContext::isDynamic() const {
switch (_outputELFType) {
case llvm::ELF::ET_EXEC:
return !_isStaticExecutable;
case llvm::ELF::ET_DYN:
return true;
}
return false;
}
bool ELFLinkingContext::isRelativeReloc(const Reference &) const {
return false;
}
Writer &ELFLinkingContext::writer() const { return *_writer; }
std::unique_ptr<ELFLinkingContext>
ELFLinkingContext::create(llvm::Triple triple) {
switch (triple.getArch()) {
case llvm::Triple::x86:
return std::unique_ptr<ELFLinkingContext>(
new lld::elf::X86LinkingContext(triple));
case llvm::Triple::x86_64:
return std::unique_ptr<ELFLinkingContext>(
new lld::elf::X86_64LinkingContext(triple));
case llvm::Triple::hexagon:
return std::unique_ptr<ELFLinkingContext>(
new lld::elf::HexagonLinkingContext(triple));
case llvm::Triple::mipsel:
return std::unique_ptr<ELFLinkingContext>(
new lld::elf::MipsLinkingContext(triple));
case llvm::Triple::ppc:
return std::unique_ptr<ELFLinkingContext>(
new lld::elf::PPCLinkingContext(triple));
default:
return nullptr;
}
}
ErrorOr<StringRef> ELFLinkingContext::searchLibrary(StringRef libName) const {
bool foundFile = false;
StringRef pathref;
SmallString<128> path;
for (StringRef dir : _inputSearchPaths) {
// Search for dynamic library
if (!_isStaticExecutable) {
path.clear();
if (dir.startswith("=/")) {
path.assign(_sysrootPath);
path.append(dir.substr(1));
} else {
path.assign(dir);
}
llvm::sys::path::append(path, Twine("lib") + libName + ".so");
pathref = path.str();
if (llvm::sys::fs::exists(pathref)) {
foundFile = true;
}
}
// Search for static libraries too
if (!foundFile) {
path.clear();
if (dir.startswith("=/")) {
path.assign(_sysrootPath);
path.append(dir.substr(1));
} else {
path.assign(dir);
}
llvm::sys::path::append(path, Twine("lib") + libName + ".a");
pathref = path.str();
if (llvm::sys::fs::exists(pathref)) {
foundFile = true;
}
}
if (foundFile)
return StringRef(*new (_allocator) std::string(pathref));
}
if (!llvm::sys::fs::exists(libName))
return llvm::make_error_code(llvm::errc::no_such_file_or_directory);
return libName;
}
std::unique_ptr<File> ELFLinkingContext::createUndefinedSymbolFile() const {
if (_initialUndefinedSymbols.empty())
return nullptr;
std::unique_ptr<SimpleFile> undefinedSymFile(
new SimpleFile("command line option -u"));
for (auto undefSymStr : _initialUndefinedSymbols)
undefinedSymFile->addAtom(*(new (_allocator) CommandLineUndefinedAtom(
*undefinedSymFile, undefSymStr)));
return std::move(undefinedSymFile);
}
} // end namespace lld
|
