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//===- Driver.cpp ---------------------------------------------------------===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "Driver.h"
#include "Config.h"
#include "Error.h"
#include "InputFiles.h"
#include "SymbolTable.h"
#include "Writer.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Path.h"
using namespace llvm;
using namespace llvm::ELF;
using namespace lld;
using namespace lld::elf2;
Configuration *lld::elf2::Config;
LinkerDriver *lld::elf2::Driver;
void lld::elf2::link(ArrayRef<const char *> Args) {
Configuration C;
LinkerDriver D;
Config = &C;
Driver = &D;
Driver->link(Args.slice(1));
}
static void setELFType(StringRef Emul) {
if (Emul == "elf_i386") {
Config->ElfKind = ELF32LEKind;
Config->EMachine = EM_386;
return;
}
if (Emul == "elf_x86_64") {
Config->ElfKind = ELF64LEKind;
Config->EMachine = EM_X86_64;
return;
}
if (Emul == "elf32ppc") {
Config->ElfKind = ELF32BEKind;
Config->EMachine = EM_PPC;
return;
}
if (Emul == "elf64ppc") {
Config->ElfKind = ELF64BEKind;
Config->EMachine = EM_PPC64;
return;
}
error(Twine("Unknown emulation: ") + Emul);
}
// Makes a path by concatenating Dir and File.
// If Dir starts with '=' the result will be preceded by Sysroot,
// which can be set with --sysroot command line switch.
static std::string buildSysrootedPath(StringRef Dir, StringRef File) {
SmallString<128> Path;
if (Dir.startswith("="))
sys::path::append(Path, Config->Sysroot, Dir.substr(1), File);
else
sys::path::append(Path, Dir, File);
return Path.str().str();
}
// Searches a given library from input search paths, which are filled
// from -L command line switches. Returns a path to an existent library file.
static std::string searchLibrary(StringRef Path) {
std::vector<std::string> Names;
if (Path[0] == ':') {
Names.push_back(Path.drop_front().str());
} else {
if (!Config->Static)
Names.push_back((Twine("lib") + Path + ".so").str());
Names.push_back((Twine("lib") + Path + ".a").str());
}
for (StringRef Dir : Config->InputSearchPaths) {
for (const std::string &Name : Names) {
std::string FullPath = buildSysrootedPath(Dir, Name);
if (sys::fs::exists(FullPath))
return FullPath;
}
}
error(Twine("Unable to find library -l") + Path);
}
template <template <class> class T>
std::unique_ptr<ELFFileBase>
LinkerDriver::createELFInputFile(MemoryBufferRef MB) {
std::unique_ptr<ELFFileBase> File = createELFFile<T>(MB);
const ELFKind ElfKind = File->getELFKind();
const uint16_t EMachine = File->getEMachine();
// Grab target from the first input file if wasn't set by -m option.
if (Config->ElfKind == ELFNoneKind) {
Config->ElfKind = ElfKind;
Config->EMachine = EMachine;
return File;
}
if (ElfKind == Config->ElfKind && EMachine == Config->EMachine)
return File;
if (const ELFFileBase *First = Symtab.getFirstELF())
error(MB.getBufferIdentifier() + " is incompatible with " +
First->getName());
error(MB.getBufferIdentifier() + " is incompatible with target architecture");
}
// Opens and parses a file. Path has to be resolved already.
// Newly created memory buffers are owned by this driver.
void LinkerDriver::addFile(StringRef Path) {
using namespace llvm::sys::fs;
auto MBOrErr = MemoryBuffer::getFile(Path);
error(MBOrErr, Twine("cannot open ") + Path);
std::unique_ptr<MemoryBuffer> &MB = *MBOrErr;
MemoryBufferRef MBRef = MB->getMemBufferRef();
OwningMBs.push_back(std::move(MB)); // take MB ownership
switch (identify_magic(MBRef.getBuffer())) {
case file_magic::unknown:
readLinkerScript(MBRef);
return;
case file_magic::archive:
Symtab.addFile(make_unique<ArchiveFile>(MBRef));
return;
case file_magic::elf_shared_object:
Symtab.addFile(createELFInputFile<SharedFile>(MBRef));
return;
default:
Symtab.addFile(createELFInputFile<ObjectFile>(MBRef));
}
}
void LinkerDriver::link(ArrayRef<const char *> ArgsArr) {
// Parse command line options.
opt::InputArgList Args = Parser.parse(ArgsArr);
if (auto *Arg = Args.getLastArg(OPT_output))
Config->OutputFile = Arg->getValue();
if (auto *Arg = Args.getLastArg(OPT_dynamic_linker))
Config->DynamicLinker = Arg->getValue();
if (auto *Arg = Args.getLastArg(OPT_sysroot))
Config->Sysroot = Arg->getValue();
std::vector<StringRef> RPaths;
for (auto *Arg : Args.filtered(OPT_rpath))
RPaths.push_back(Arg->getValue());
if (!RPaths.empty())
Config->RPath = llvm::join(RPaths.begin(), RPaths.end(), ":");
for (auto *Arg : Args.filtered(OPT_L))
Config->InputSearchPaths.push_back(Arg->getValue());
if (auto *Arg = Args.getLastArg(OPT_entry))
Config->Entry = Arg->getValue();
if (auto *Arg = Args.getLastArg(OPT_fini))
Config->Fini = Arg->getValue();
if (auto *Arg = Args.getLastArg(OPT_init))
Config->Init = Arg->getValue();
if (auto *Arg = Args.getLastArg(OPT_soname))
Config->SoName = Arg->getValue();
if (auto *Arg = Args.getLastArg(OPT_m))
setELFType(Arg->getValue());
Config->AllowMultipleDefinition = Args.hasArg(OPT_allow_multiple_definition);
Config->DiscardAll = Args.hasArg(OPT_discard_all);
Config->DiscardLocals = Args.hasArg(OPT_discard_locals);
Config->DiscardNone = Args.hasArg(OPT_discard_none);
Config->EnableNewDtags = !Args.hasArg(OPT_disable_new_dtags);
Config->ExportDynamic = Args.hasArg(OPT_export_dynamic);
Config->NoInhibitExec = Args.hasArg(OPT_noinhibit_exec);
Config->NoUndefined = Args.hasArg(OPT_no_undefined);
Config->Shared = Args.hasArg(OPT_shared);
for (auto *Arg : Args) {
switch (Arg->getOption().getID()) {
case OPT_l:
addFile(searchLibrary(Arg->getValue()));
break;
case OPT_INPUT:
addFile(Arg->getValue());
break;
case OPT_Bstatic:
Config->Static = true;
break;
case OPT_Bdynamic:
Config->Static = false;
break;
case OPT_whole_archive:
Config->WholeArchive = true;
break;
case OPT_no_whole_archive:
Config->WholeArchive = false;
break;
default:
break;
}
}
if (Symtab.getObjectFiles().empty())
error("no input files.");
for (auto *Arg : Args.filtered(OPT_undefined))
Symtab.addUndefinedSym(Arg->getValue());
if (Config->OutputFile.empty())
Config->OutputFile = "a.out";
// Write the result.
const ELFFileBase *FirstObj = Symtab.getFirstELF();
switch (FirstObj->getELFKind()) {
case ELF32LEKind:
writeResult<object::ELF32LE>(&Symtab);
return;
case ELF32BEKind:
writeResult<object::ELF32BE>(&Symtab);
return;
case ELF64LEKind:
writeResult<object::ELF64LE>(&Symtab);
return;
case ELF64BEKind:
writeResult<object::ELF64BE>(&Symtab);
return;
default:
llvm_unreachable("Invalid kind");
}
}
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