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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/Errc.h"
#include "llvm/Support/ELF.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Path.h"
namespace lld {
class CommandLineAbsoluteAtom : public AbsoluteAtom {
public:
CommandLineAbsoluteAtom(const File &file, StringRef name, uint64_t value)
: _file(file), _name(name), _value(value) {}
const File &file() const override { return _file; }
StringRef name() const override { return _name; }
uint64_t value() const override { return _value; }
Scope scope() const override { return scopeGlobal; }
private:
const File &_file;
StringRef _name;
uint64_t _value;
};
class CommandLineUndefinedAtom : public SimpleUndefinedAtom {
public:
CommandLineUndefinedAtom(const File &f, StringRef name)
: SimpleUndefinedAtom(f, name) {}
CanBeNull canBeNull() const override {
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(registry())));
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;
}
}
static void buildSearchPath(SmallString<128> &path, StringRef dir,
StringRef sysRoot) {
if (!dir.startswith("=/"))
path.assign(dir);
else {
path.assign(sysRoot);
path.append(dir.substr(1));
}
}
ErrorOr<StringRef> ELFLinkingContext::searchLibrary(StringRef libName) const {
bool hasColonPrefix = libName[0] == ':';
Twine soName =
hasColonPrefix ? libName.drop_front() : Twine("lib", libName) + ".so";
Twine archiveName =
hasColonPrefix ? libName.drop_front() : Twine("lib", libName) + ".a";
SmallString<128> path;
for (StringRef dir : _inputSearchPaths) {
// Search for dynamic library
if (!_isStaticExecutable) {
buildSearchPath(path, dir, _sysrootPath);
llvm::sys::path::append(path, soName);
if (llvm::sys::fs::exists(path.str()))
return StringRef(*new (_allocator) std::string(path.str()));
}
// Search for static libraries too
buildSearchPath(path, dir, _sysrootPath);
llvm::sys::path::append(path, archiveName);
if (llvm::sys::fs::exists(path.str()))
return StringRef(*new (_allocator) std::string(path.str()));
}
if (!llvm::sys::fs::exists(libName))
return make_error_code(llvm::errc::no_such_file_or_directory);
return libName;
}
ErrorOr<StringRef> ELFLinkingContext::searchFile(StringRef fileName,
bool isSysRooted) const {
SmallString<128> path;
if (llvm::sys::path::is_absolute(fileName) && isSysRooted) {
path.assign(_sysrootPath);
path.append(fileName);
if (llvm::sys::fs::exists(path.str()))
return StringRef(*new (_allocator) std::string(path.str()));
} else if (llvm::sys::fs::exists(fileName))
return fileName;
if (llvm::sys::path::is_absolute(fileName))
return make_error_code(llvm::errc::no_such_file_or_directory);
for (StringRef dir : _inputSearchPaths) {
buildSearchPath(path, dir, _sysrootPath);
llvm::sys::path::append(path, fileName);
if (llvm::sys::fs::exists(path.str()))
return StringRef(*new (_allocator) std::string(path.str()));
}
return make_error_code(llvm::errc::no_such_file_or_directory);
}
void ELFLinkingContext::createInternalFiles(
std::vector<std::unique_ptr<File>> &files) const {
std::unique_ptr<SimpleFile> file(
new SimpleFile("<internal file for --defsym>"));
for (auto &i : getAbsoluteSymbols()) {
StringRef sym = i.first;
uint64_t val = i.second;
file->addAtom(*(new (_allocator) CommandLineAbsoluteAtom(*file, sym, val)));
}
files.push_back(std::move(file));
LinkingContext::createInternalFiles(files);
}
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
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