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llvm-6502/tools/gold/gold-plugin.cpp
Rafael Espindola d3732d9095 Simplify the handling of aliases in the gold plugin. 
The complicated situation is when we have to keep an alias but drop a GV
that is part of the aliasee.

We used to clone the dropped GV and make the clone internal. This is wasteful
as we know the original will be dropped.

With this patch what is done instead is set the linkage of the original to
internal and replace all uses (but the one in the alias) with a new
declaration that takes the name of the old GV. This saves us from having
to copy the body.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223863 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-10 00:09:35 +00:00

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//===-- gold-plugin.cpp - Plugin to gold for Link Time Optimization ------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This is a gold plugin for LLVM. It provides an LLVM implementation of the
// interface described in http://gcc.gnu.org/wiki/whopr/driver .
//
//===----------------------------------------------------------------------===//
#include "llvm/Config/config.h" // plugin-api.h requires HAVE_STDINT_H
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/StringSet.h"
#include "llvm/Bitcode/ReaderWriter.h"
#include "llvm/CodeGen/Analysis.h"
#include "llvm/CodeGen/CommandFlags.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Verifier.h"
#include "llvm/Linker/Linker.h"
#include "llvm/MC/SubtargetFeature.h"
#include "llvm/Object/IRObjectFile.h"
#include "llvm/PassManager.h"
#include "llvm/Support/FormattedStream.h"
#include "llvm/Support/Host.h"
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/TargetSelect.h"
#include "llvm/Target/TargetLibraryInfo.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/IPO/PassManagerBuilder.h"
#include "llvm/Transforms/Utils/GlobalStatus.h"
#include "llvm/Transforms/Utils/ModuleUtils.h"
#include "llvm/Transforms/Utils/ValueMapper.h"
#include <list>
#include <plugin-api.h>
#include <system_error>
#include <vector>
#ifndef LDPO_PIE
// FIXME: remove this declaration when we stop maintaining Ubuntu Quantal and
// Precise and Debian Wheezy (binutils 2.23 is required)
# define LDPO_PIE 3
#endif
using namespace llvm;
namespace {
struct claimed_file {
void *handle;
std::vector<ld_plugin_symbol> syms;
};
}
static ld_plugin_status discard_message(int level, const char *format, ...) {
// Die loudly. Recent versions of Gold pass ld_plugin_message as the first
// callback in the transfer vector. This should never be called.
abort();
}
static ld_plugin_get_input_file get_input_file = nullptr;
static ld_plugin_release_input_file release_input_file = nullptr;
static ld_plugin_add_symbols add_symbols = nullptr;
static ld_plugin_get_symbols get_symbols = nullptr;
static ld_plugin_add_input_file add_input_file = nullptr;
static ld_plugin_set_extra_library_path set_extra_library_path = nullptr;
static ld_plugin_get_view get_view = nullptr;
static ld_plugin_message message = discard_message;
static Reloc::Model RelocationModel = Reloc::Default;
static std::string output_name = "";
static std::list<claimed_file> Modules;
static std::vector<std::string> Cleanup;
static llvm::TargetOptions TargetOpts;
namespace options {
enum OutputType {
OT_NORMAL,
OT_DISABLE,
OT_BC_ONLY,
OT_SAVE_TEMPS
};
static bool generate_api_file = false;
static OutputType TheOutputType = OT_NORMAL;
static std::string obj_path;
static std::string extra_library_path;
static std::string triple;
static std::string mcpu;
// Additional options to pass into the code generator.
// Note: This array will contain all plugin options which are not claimed
// as plugin exclusive to pass to the code generator.
// For example, "generate-api-file" and "as"options are for the plugin
// use only and will not be passed.
static std::vector<const char *> extra;
static void process_plugin_option(const char* opt_)
{
if (opt_ == nullptr)
return;
llvm::StringRef opt = opt_;
if (opt == "generate-api-file") {
generate_api_file = true;
} else if (opt.startswith("mcpu=")) {
mcpu = opt.substr(strlen("mcpu="));
} else if (opt.startswith("extra-library-path=")) {
extra_library_path = opt.substr(strlen("extra_library_path="));
} else if (opt.startswith("mtriple=")) {
triple = opt.substr(strlen("mtriple="));
} else if (opt.startswith("obj-path=")) {
obj_path = opt.substr(strlen("obj-path="));
} else if (opt == "emit-llvm") {
TheOutputType = OT_BC_ONLY;
} else if (opt == "save-temps") {
TheOutputType = OT_SAVE_TEMPS;
} else if (opt == "disable-output") {
TheOutputType = OT_DISABLE;
} else {
// Save this option to pass to the code generator.
// ParseCommandLineOptions() expects argv[0] to be program name. Lazily
// add that.
if (extra.empty())
extra.push_back("LLVMgold");
extra.push_back(opt_);
}
}
}
static ld_plugin_status claim_file_hook(const ld_plugin_input_file *file,
int *claimed);
static ld_plugin_status all_symbols_read_hook(void);
static ld_plugin_status cleanup_hook(void);
extern "C" ld_plugin_status onload(ld_plugin_tv *tv);
ld_plugin_status onload(ld_plugin_tv *tv) {
InitializeAllTargetInfos();
InitializeAllTargets();
InitializeAllTargetMCs();
InitializeAllAsmParsers();
InitializeAllAsmPrinters();
// We're given a pointer to the first transfer vector. We read through them
// until we find one where tv_tag == LDPT_NULL. The REGISTER_* tagged values
// contain pointers to functions that we need to call to register our own
// hooks. The others are addresses of functions we can use to call into gold
// for services.
bool registeredClaimFile = false;
bool RegisteredAllSymbolsRead = false;
for (; tv->tv_tag != LDPT_NULL; ++tv) {
switch (tv->tv_tag) {
case LDPT_OUTPUT_NAME:
output_name = tv->tv_u.tv_string;
break;
case LDPT_LINKER_OUTPUT:
switch (tv->tv_u.tv_val) {
case LDPO_REL: // .o
case LDPO_DYN: // .so
case LDPO_PIE: // position independent executable
RelocationModel = Reloc::PIC_;
break;
case LDPO_EXEC: // .exe
RelocationModel = Reloc::Static;
break;
default:
message(LDPL_ERROR, "Unknown output file type %d", tv->tv_u.tv_val);
return LDPS_ERR;
}
break;
case LDPT_OPTION:
options::process_plugin_option(tv->tv_u.tv_string);
break;
case LDPT_REGISTER_CLAIM_FILE_HOOK: {
ld_plugin_register_claim_file callback;
callback = tv->tv_u.tv_register_claim_file;
if (callback(claim_file_hook) != LDPS_OK)
return LDPS_ERR;
registeredClaimFile = true;
} break;
case LDPT_REGISTER_ALL_SYMBOLS_READ_HOOK: {
ld_plugin_register_all_symbols_read callback;
callback = tv->tv_u.tv_register_all_symbols_read;
if (callback(all_symbols_read_hook) != LDPS_OK)
return LDPS_ERR;
RegisteredAllSymbolsRead = true;
} break;
case LDPT_REGISTER_CLEANUP_HOOK: {
ld_plugin_register_cleanup callback;
callback = tv->tv_u.tv_register_cleanup;
if (callback(cleanup_hook) != LDPS_OK)
return LDPS_ERR;
} break;
case LDPT_GET_INPUT_FILE:
get_input_file = tv->tv_u.tv_get_input_file;
break;
case LDPT_RELEASE_INPUT_FILE:
release_input_file = tv->tv_u.tv_release_input_file;
break;
case LDPT_ADD_SYMBOLS:
add_symbols = tv->tv_u.tv_add_symbols;
break;
case LDPT_GET_SYMBOLS_V2:
get_symbols = tv->tv_u.tv_get_symbols;
break;
case LDPT_ADD_INPUT_FILE:
add_input_file = tv->tv_u.tv_add_input_file;
break;
case LDPT_SET_EXTRA_LIBRARY_PATH:
set_extra_library_path = tv->tv_u.tv_set_extra_library_path;
break;
case LDPT_GET_VIEW:
get_view = tv->tv_u.tv_get_view;
break;
case LDPT_MESSAGE:
message = tv->tv_u.tv_message;
break;
default:
break;
}
}
if (!registeredClaimFile) {
message(LDPL_ERROR, "register_claim_file not passed to LLVMgold.");
return LDPS_ERR;
}
if (!add_symbols) {
message(LDPL_ERROR, "add_symbols not passed to LLVMgold.");
return LDPS_ERR;
}
if (!RegisteredAllSymbolsRead)
return LDPS_OK;
if (!get_input_file) {
message(LDPL_ERROR, "get_input_file not passed to LLVMgold.");
return LDPS_ERR;
}
if (!release_input_file) {
message(LDPL_ERROR, "relesase_input_file not passed to LLVMgold.");
return LDPS_ERR;
}
return LDPS_OK;
}
static const GlobalObject *getBaseObject(const GlobalValue &GV) {
if (auto *GA = dyn_cast<GlobalAlias>(&GV))
return GA->getBaseObject();
return cast<GlobalObject>(&GV);
}
static bool shouldSkip(uint32_t Symflags) {
if (!(Symflags & object::BasicSymbolRef::SF_Global))
return true;
if (Symflags & object::BasicSymbolRef::SF_FormatSpecific)
return true;
return false;
}
/// Called by gold to see whether this file is one that our plugin can handle.
/// We'll try to open it and register all the symbols with add_symbol if
/// possible.
static ld_plugin_status claim_file_hook(const ld_plugin_input_file *file,
int *claimed) {
LLVMContext Context;
MemoryBufferRef BufferRef;
std::unique_ptr<MemoryBuffer> Buffer;
if (get_view) {
const void *view;
if (get_view(file->handle, &view) != LDPS_OK) {
message(LDPL_ERROR, "Failed to get a view of %s", file->name);
return LDPS_ERR;
}
BufferRef = MemoryBufferRef(StringRef((const char *)view, file->filesize), "");
} else {
int64_t offset = 0;
// Gold has found what might be IR part-way inside of a file, such as
// an .a archive.
if (file->offset) {
offset = file->offset;
}
ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOrErr =
MemoryBuffer::getOpenFileSlice(file->fd, file->name, file->filesize,
offset);
if (std::error_code EC = BufferOrErr.getError()) {
message(LDPL_ERROR, EC.message().c_str());
return LDPS_ERR;
}
Buffer = std::move(BufferOrErr.get());
BufferRef = Buffer->getMemBufferRef();
}
ErrorOr<std::unique_ptr<object::IRObjectFile>> ObjOrErr =
object::IRObjectFile::create(BufferRef, Context);
std::error_code EC = ObjOrErr.getError();
if (EC == BitcodeError::InvalidBitcodeSignature ||
EC == object::object_error::invalid_file_type ||
EC == object::object_error::bitcode_section_not_found)
return LDPS_OK;
*claimed = 1;
if (EC) {
message(LDPL_ERROR, "LLVM gold plugin has failed to create LTO module: %s",
EC.message().c_str());
return LDPS_ERR;
}
std::unique_ptr<object::IRObjectFile> Obj = std::move(*ObjOrErr);
Modules.resize(Modules.size() + 1);
claimed_file &cf = Modules.back();
cf.handle = file->handle;
for (auto &Sym : Obj->symbols()) {
uint32_t Symflags = Sym.getFlags();
if (shouldSkip(Symflags))
continue;
cf.syms.push_back(ld_plugin_symbol());
ld_plugin_symbol &sym = cf.syms.back();
sym.version = nullptr;
SmallString<64> Name;
{
raw_svector_ostream OS(Name);
Sym.printName(OS);
}
sym.name = strdup(Name.c_str());
const GlobalValue *GV = Obj->getSymbolGV(Sym.getRawDataRefImpl());
sym.visibility = LDPV_DEFAULT;
if (GV) {
switch (GV->getVisibility()) {
case GlobalValue::DefaultVisibility:
sym.visibility = LDPV_DEFAULT;
break;
case GlobalValue::HiddenVisibility:
sym.visibility = LDPV_HIDDEN;
break;
case GlobalValue::ProtectedVisibility:
sym.visibility = LDPV_PROTECTED;
break;
}
}
if (Symflags & object::BasicSymbolRef::SF_Undefined) {
sym.def = LDPK_UNDEF;
if (GV && GV->hasExternalWeakLinkage())
sym.def = LDPK_WEAKUNDEF;
} else {
sym.def = LDPK_DEF;
if (GV) {
assert(!GV->hasExternalWeakLinkage() &&
!GV->hasAvailableExternallyLinkage() && "Not a declaration!");
if (GV->hasCommonLinkage())
sym.def = LDPK_COMMON;
else if (GV->isWeakForLinker())
sym.def = LDPK_WEAKDEF;
}
}
sym.size = 0;
sym.comdat_key = nullptr;
if (GV) {
const GlobalObject *Base = getBaseObject(*GV);
if (!Base)
message(LDPL_FATAL, "Unable to determine comdat of alias!");
const Comdat *C = Base->getComdat();
if (C)
sym.comdat_key = strdup(C->getName().str().c_str());
else if (Base->hasWeakLinkage() || Base->hasLinkOnceLinkage())
sym.comdat_key = strdup(sym.name);
}
sym.resolution = LDPR_UNKNOWN;
}
if (!cf.syms.empty()) {
if (add_symbols(cf.handle, cf.syms.size(), &cf.syms[0]) != LDPS_OK) {
message(LDPL_ERROR, "Unable to add symbols!");
return LDPS_ERR;
}
}
return LDPS_OK;
}
static void keepGlobalValue(GlobalValue &GV,
std::vector<GlobalAlias *> &KeptAliases) {
assert(!GV.hasLocalLinkage());
if (auto *GA = dyn_cast<GlobalAlias>(&GV))
KeptAliases.push_back(GA);
switch (GV.getLinkage()) {
default:
break;
case GlobalValue::LinkOnceAnyLinkage:
GV.setLinkage(GlobalValue::WeakAnyLinkage);
break;
case GlobalValue::LinkOnceODRLinkage:
GV.setLinkage(GlobalValue::WeakODRLinkage);
break;
}
assert(!GV.isDiscardableIfUnused());
}
static void internalize(GlobalValue &GV) {
if (GV.isDeclarationForLinker())
return; // We get here if there is a matching asm definition.
if (!GV.hasLocalLinkage())
GV.setLinkage(GlobalValue::InternalLinkage);
}
static void drop(GlobalValue &GV) {
if (auto *F = dyn_cast<Function>(&GV)) {
F->deleteBody();
F->setComdat(nullptr); // Should deleteBody do this?
return;
}
if (auto *Var = dyn_cast<GlobalVariable>(&GV)) {
Var->setInitializer(nullptr);
Var->setLinkage(
GlobalValue::ExternalLinkage); // Should setInitializer do this?
Var->setComdat(nullptr); // and this?
return;
}
auto &Alias = cast<GlobalAlias>(GV);
Module &M = *Alias.getParent();
PointerType &Ty = *cast<PointerType>(Alias.getType());
GlobalValue::LinkageTypes L = Alias.getLinkage();
auto *Var =
new GlobalVariable(M, Ty.getElementType(), /*isConstant*/ false, L,
/*Initializer*/ nullptr);
Var->takeName(&Alias);
Alias.replaceAllUsesWith(Var);
Alias.eraseFromParent();
}
static const char *getResolutionName(ld_plugin_symbol_resolution R) {
switch (R) {
case LDPR_UNKNOWN:
return "UNKNOWN";
case LDPR_UNDEF:
return "UNDEF";
case LDPR_PREVAILING_DEF:
return "PREVAILING_DEF";
case LDPR_PREVAILING_DEF_IRONLY:
return "PREVAILING_DEF_IRONLY";
case LDPR_PREEMPTED_REG:
return "PREEMPTED_REG";
case LDPR_PREEMPTED_IR:
return "PREEMPTED_IR";
case LDPR_RESOLVED_IR:
return "RESOLVED_IR";
case LDPR_RESOLVED_EXEC:
return "RESOLVED_EXEC";
case LDPR_RESOLVED_DYN:
return "RESOLVED_DYN";
case LDPR_PREVAILING_DEF_IRONLY_EXP:
return "PREVAILING_DEF_IRONLY_EXP";
}
llvm_unreachable("Unknown resolution");
}
namespace {
class LocalValueMaterializer : public ValueMaterializer {
DenseSet<GlobalValue *> &Dropped;
DenseMap<GlobalObject *, GlobalObject *> LocalVersions;
public:
LocalValueMaterializer(DenseSet<GlobalValue *> &Dropped) : Dropped(Dropped) {}
Value *materializeValueFor(Value *V) override;
};
}
Value *LocalValueMaterializer::materializeValueFor(Value *V) {
auto *GO = dyn_cast<GlobalObject>(V);
if (!GO)
return nullptr;
auto I = LocalVersions.find(GO);
if (I != LocalVersions.end())
return I->second;
if (!Dropped.count(GO))
return nullptr;
Module &M = *GO->getParent();
GlobalValue::LinkageTypes L = GO->getLinkage();
GlobalObject *Declaration;
if (auto *F = dyn_cast<Function>(GO)) {
Declaration = Function::Create(F->getFunctionType(), L, "", &M);
} else {
auto *Var = cast<GlobalVariable>(GO);
Declaration = new GlobalVariable(M, Var->getType()->getElementType(),
Var->isConstant(), L,
/*Initializer*/ nullptr);
}
Declaration->takeName(GO);
Declaration->copyAttributesFrom(GO);
GO->setLinkage(GlobalValue::InternalLinkage);
GO->setName(Declaration->getName());
Dropped.erase(GO);
GO->replaceAllUsesWith(Declaration);
LocalVersions[Declaration] = GO;
return GO;
}
static Constant *mapConstantToLocalCopy(Constant *C, ValueToValueMapTy &VM,
LocalValueMaterializer *Materializer) {
return MapValue(C, VM, RF_IgnoreMissingEntries, nullptr, Materializer);
}
static std::unique_ptr<Module>
getModuleForFile(LLVMContext &Context, claimed_file &F, raw_fd_ostream *ApiFile,
StringSet<> &Internalize, StringSet<> &Maybe) {
ld_plugin_input_file File;
if (get_input_file(F.handle, &File) != LDPS_OK)
message(LDPL_FATAL, "Failed to get file information");
if (get_symbols(F.handle, F.syms.size(), &F.syms[0]) != LDPS_OK)
message(LDPL_FATAL, "Failed to get symbol information");
const void *View;
if (get_view(F.handle, &View) != LDPS_OK)
message(LDPL_FATAL, "Failed to get a view of file");
MemoryBufferRef BufferRef(StringRef((const char *)View, File.filesize), "");
ErrorOr<std::unique_ptr<object::IRObjectFile>> ObjOrErr =
object::IRObjectFile::create(BufferRef, Context);
if (std::error_code EC = ObjOrErr.getError())
message(LDPL_FATAL, "Could not read bitcode from file : %s",
EC.message().c_str());
if (release_input_file(F.handle) != LDPS_OK)
message(LDPL_FATAL, "Failed to release file information");
object::IRObjectFile &Obj = **ObjOrErr;
Module &M = Obj.getModule();
SmallPtrSet<GlobalValue *, 8> Used;
collectUsedGlobalVariables(M, Used, /*CompilerUsed*/ false);
DenseSet<GlobalValue *> Drop;
std::vector<GlobalAlias *> KeptAliases;
unsigned SymNum = 0;
for (auto &ObjSym : Obj.symbols()) {
if (shouldSkip(ObjSym.getFlags()))
continue;
ld_plugin_symbol &Sym = F.syms[SymNum];
++SymNum;
ld_plugin_symbol_resolution Resolution =
(ld_plugin_symbol_resolution)Sym.resolution;
if (options::generate_api_file)
*ApiFile << Sym.name << ' ' << getResolutionName(Resolution) << '\n';
GlobalValue *GV = Obj.getSymbolGV(ObjSym.getRawDataRefImpl());
if (!GV)
continue; // Asm symbol.
if (Resolution != LDPR_PREVAILING_DEF_IRONLY && GV->hasCommonLinkage()) {
// Common linkage is special. There is no single symbol that wins the
// resolution. Instead we have to collect the maximum alignment and size.
// The IR linker does that for us if we just pass it every common GV.
// We still have to keep track of LDPR_PREVAILING_DEF_IRONLY so we
// internalize once the IR linker has done its job.
continue;
}
switch (Resolution) {
case LDPR_UNKNOWN:
llvm_unreachable("Unexpected resolution");
case LDPR_RESOLVED_IR:
case LDPR_RESOLVED_EXEC:
case LDPR_RESOLVED_DYN:
case LDPR_UNDEF:
assert(GV->isDeclarationForLinker());
break;
case LDPR_PREVAILING_DEF_IRONLY: {
keepGlobalValue(*GV, KeptAliases);
if (!Used.count(GV)) {
// Since we use the regular lib/Linker, we cannot just internalize GV
// now or it will not be copied to the merged module. Instead we force
// it to be copied and then internalize it.
Internalize.insert(GV->getName());
}
break;
}
case LDPR_PREVAILING_DEF:
keepGlobalValue(*GV, KeptAliases);
break;
case LDPR_PREEMPTED_IR:
// Gold might have selected a linkonce_odr and preempted a weak_odr.
// In that case we have to make sure we don't end up internalizing it.
if (!GV->isDiscardableIfUnused())
Maybe.erase(GV->getName());
// fall-through
case LDPR_PREEMPTED_REG:
Drop.insert(GV);
break;
case LDPR_PREVAILING_DEF_IRONLY_EXP: {
// We can only check for address uses after we merge the modules. The
// reason is that this GV might have a copy in another module
// and in that module the address might be significant, but that
// copy will be LDPR_PREEMPTED_IR.
if (GV->hasLinkOnceODRLinkage())
Maybe.insert(GV->getName());
keepGlobalValue(*GV, KeptAliases);
break;
}
}
free(Sym.name);
free(Sym.comdat_key);
Sym.name = nullptr;
Sym.comdat_key = nullptr;
}
ValueToValueMapTy VM;
LocalValueMaterializer Materializer(Drop);
for (GlobalAlias *GA : KeptAliases) {
// Gold told us to keep GA. It is possible that a GV usied in the aliasee
// expression is being dropped. If that is the case, that GV must be copied.
Constant *Aliasee = GA->getAliasee();
Constant *Replacement = mapConstantToLocalCopy(Aliasee, VM, &Materializer);
GA->setAliasee(Replacement);
}
for (auto *GV : Drop)
drop(*GV);
return Obj.takeModule();
}
static void runLTOPasses(Module &M, TargetMachine &TM) {
PassManager passes;
PassManagerBuilder PMB;
PMB.LibraryInfo = new TargetLibraryInfo(Triple(TM.getTargetTriple()));
PMB.Inliner = createFunctionInliningPass();
PMB.VerifyInput = true;
PMB.VerifyOutput = true;
PMB.LoopVectorize = true;
PMB.SLPVectorize = true;
PMB.populateLTOPassManager(passes, &TM);
passes.run(M);
}
static void saveBCFile(StringRef Path, Module &M) {
std::error_code EC;
raw_fd_ostream OS(Path, EC, sys::fs::OpenFlags::F_None);
if (EC)
message(LDPL_FATAL, "Failed to write the output file.");
WriteBitcodeToFile(&M, OS);
}
static void codegen(Module &M) {
const std::string &TripleStr = M.getTargetTriple();
Triple TheTriple(TripleStr);
std::string ErrMsg;
const Target *TheTarget = TargetRegistry::lookupTarget(TripleStr, ErrMsg);
if (!TheTarget)
message(LDPL_FATAL, "Target not found: %s", ErrMsg.c_str());
if (unsigned NumOpts = options::extra.size())
cl::ParseCommandLineOptions(NumOpts, &options::extra[0]);
SubtargetFeatures Features;
Features.getDefaultSubtargetFeatures(TheTriple);
for (const std::string &A : MAttrs)
Features.AddFeature(A);
TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
std::unique_ptr<TargetMachine> TM(TheTarget->createTargetMachine(
TripleStr, options::mcpu, Features.getString(), Options, RelocationModel,
CodeModel::Default, CodeGenOpt::Aggressive));
runLTOPasses(M, *TM);
if (options::TheOutputType == options::OT_SAVE_TEMPS)
saveBCFile(output_name + ".opt.bc", M);
PassManager CodeGenPasses;
CodeGenPasses.add(new DataLayoutPass());
SmallString<128> Filename;
int FD;
if (options::obj_path.empty()) {
std::error_code EC =
sys::fs::createTemporaryFile("lto-llvm", "o", FD, Filename);
if (EC)
message(LDPL_FATAL, "Could not create temporary file: %s",
EC.message().c_str());
} else {
Filename = options::obj_path;
std::error_code EC =
sys::fs::openFileForWrite(Filename.c_str(), FD, sys::fs::F_None);
if (EC)
message(LDPL_FATAL, "Could not open file: %s", EC.message().c_str());
}
{
raw_fd_ostream OS(FD, true);
formatted_raw_ostream FOS(OS);
if (TM->addPassesToEmitFile(CodeGenPasses, FOS,
TargetMachine::CGFT_ObjectFile))
message(LDPL_FATAL, "Failed to setup codegen");
CodeGenPasses.run(M);
}
if (add_input_file(Filename.c_str()) != LDPS_OK)
message(LDPL_FATAL,
"Unable to add .o file to the link. File left behind in: %s",
Filename.c_str());
if (options::obj_path.empty())
Cleanup.push_back(Filename.c_str());
}
/// gold informs us that all symbols have been read. At this point, we use
/// get_symbols to see if any of our definitions have been overridden by a
/// native object file. Then, perform optimization and codegen.
static ld_plugin_status allSymbolsReadHook(raw_fd_ostream *ApiFile) {
if (Modules.empty())
return LDPS_OK;
LLVMContext Context;
std::unique_ptr<Module> Combined(new Module("ld-temp.o", Context));
Linker L(Combined.get());
std::string DefaultTriple = sys::getDefaultTargetTriple();
StringSet<> Internalize;
StringSet<> Maybe;
for (claimed_file &F : Modules) {
std::unique_ptr<Module> M =
getModuleForFile(Context, F, ApiFile, Internalize, Maybe);
if (!options::triple.empty())
M->setTargetTriple(options::triple.c_str());
else if (M->getTargetTriple().empty()) {
M->setTargetTriple(DefaultTriple);
}
if (L.linkInModule(M.get()))
message(LDPL_FATAL, "Failed to link module");
}
for (const auto &Name : Internalize) {
GlobalValue *GV = Combined->getNamedValue(Name.first());
if (GV)
internalize(*GV);
}
for (const auto &Name : Maybe) {
GlobalValue *GV = Combined->getNamedValue(Name.first());
if (!GV)
continue;
GV->setLinkage(GlobalValue::LinkOnceODRLinkage);
if (canBeOmittedFromSymbolTable(GV))
internalize(*GV);
}
if (options::TheOutputType == options::OT_DISABLE)
return LDPS_OK;
if (options::TheOutputType != options::OT_NORMAL) {
std::string path;
if (options::TheOutputType == options::OT_BC_ONLY)
path = output_name;
else
path = output_name + ".bc";
saveBCFile(path, *L.getModule());
if (options::TheOutputType == options::OT_BC_ONLY)
return LDPS_OK;
}
codegen(*L.getModule());
if (!options::extra_library_path.empty() &&
set_extra_library_path(options::extra_library_path.c_str()) != LDPS_OK)
message(LDPL_FATAL, "Unable to set the extra library path.");
return LDPS_OK;
}
static ld_plugin_status all_symbols_read_hook(void) {
ld_plugin_status Ret;
if (!options::generate_api_file) {
Ret = allSymbolsReadHook(nullptr);
} else {
std::error_code EC;
raw_fd_ostream ApiFile("apifile.txt", EC, sys::fs::F_None);
if (EC)
message(LDPL_FATAL, "Unable to open apifile.txt for writing: %s",
EC.message().c_str());
Ret = allSymbolsReadHook(&ApiFile);
}
llvm_shutdown();
if (options::TheOutputType == options::OT_BC_ONLY ||
options::TheOutputType == options::OT_DISABLE)
exit(0);
return Ret;
}
static ld_plugin_status cleanup_hook(void) {
for (std::string &Name : Cleanup) {
std::error_code EC = sys::fs::remove(Name);
if (EC)
message(LDPL_ERROR, "Failed to delete '%s': %s", Name.c_str(),
EC.message().c_str());
}
return LDPS_OK;
}
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