llvm/tools/lto/LTOCodeGenerator.cpp
Nick Lewycky 8a8d479214 Move global variables in TargetMachine into new TargetOptions class. As an API
change, now you need a TargetOptions object to create a TargetMachine. Clang
patch to follow.

One small functionality change in PTX. PTX had commented out the machine
verifier parts in their copy of printAndVerify. That now calls the version in
LLVMTargetMachine. Users of PTX who need verification disabled should rely on
not passing the command-line flag to enable it.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145714 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-02 22:16:29 +00:00

433 lines
13 KiB
C++

//===-LTOCodeGenerator.cpp - LLVM Link Time Optimizer ---------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the Link Time Optimization library. This library is
// intended to be used by linker to optimize code at link time.
//
//===----------------------------------------------------------------------===//
#include "LTOModule.h"
#include "LTOCodeGenerator.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Linker.h"
#include "llvm/LLVMContext.h"
#include "llvm/Module.h"
#include "llvm/PassManager.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/Triple.h"
#include "llvm/Analysis/Passes.h"
#include "llvm/Analysis/Verifier.h"
#include "llvm/Bitcode/ReaderWriter.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/SubtargetFeature.h"
#include "llvm/Target/Mangler.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/FormattedStream.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/SystemUtils.h"
#include "llvm/Support/ToolOutputFile.h"
#include "llvm/Support/Host.h"
#include "llvm/Support/Program.h"
#include "llvm/Support/Signals.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/TargetSelect.h"
#include "llvm/Support/system_error.h"
#include "llvm/Config/config.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/IPO/PassManagerBuilder.h"
#include <cstdlib>
#include <unistd.h>
#include <fcntl.h>
using namespace llvm;
static cl::opt<bool> DisableInline("disable-inlining",
cl::desc("Do not run the inliner pass"));
const char* LTOCodeGenerator::getVersionString()
{
#ifdef LLVM_VERSION_INFO
return PACKAGE_NAME " version " PACKAGE_VERSION ", " LLVM_VERSION_INFO;
#else
return PACKAGE_NAME " version " PACKAGE_VERSION;
#endif
}
LTOCodeGenerator::LTOCodeGenerator()
: _context(getGlobalContext()),
_linker("LinkTimeOptimizer", "ld-temp.o", _context), _target(NULL),
_emitDwarfDebugInfo(false), _scopeRestrictionsDone(false),
_codeModel(LTO_CODEGEN_PIC_MODEL_DYNAMIC),
_nativeObjectFile(NULL)
{
InitializeAllTargets();
InitializeAllTargetMCs();
InitializeAllAsmPrinters();
}
LTOCodeGenerator::~LTOCodeGenerator()
{
delete _target;
delete _nativeObjectFile;
}
bool LTOCodeGenerator::addModule(LTOModule* mod, std::string& errMsg)
{
bool ret = _linker.LinkInModule(mod->getLLVVMModule(), &errMsg);
const std::vector<const char*> &undefs = mod->getAsmUndefinedRefs();
for (int i = 0, e = undefs.size(); i != e; ++i)
_asmUndefinedRefs[undefs[i]] = 1;
return ret;
}
bool LTOCodeGenerator::setDebugInfo(lto_debug_model debug, std::string& errMsg)
{
switch (debug) {
case LTO_DEBUG_MODEL_NONE:
_emitDwarfDebugInfo = false;
return false;
case LTO_DEBUG_MODEL_DWARF:
_emitDwarfDebugInfo = true;
return false;
}
errMsg = "unknown debug format";
return true;
}
bool LTOCodeGenerator::setCodePICModel(lto_codegen_model model,
std::string& errMsg)
{
switch (model) {
case LTO_CODEGEN_PIC_MODEL_STATIC:
case LTO_CODEGEN_PIC_MODEL_DYNAMIC:
case LTO_CODEGEN_PIC_MODEL_DYNAMIC_NO_PIC:
_codeModel = model;
return false;
}
errMsg = "unknown pic model";
return true;
}
void LTOCodeGenerator::setCpu(const char* mCpu)
{
_mCpu = mCpu;
}
void LTOCodeGenerator::addMustPreserveSymbol(const char* sym)
{
_mustPreserveSymbols[sym] = 1;
}
bool LTOCodeGenerator::writeMergedModules(const char *path,
std::string &errMsg) {
if (determineTarget(errMsg))
return true;
// mark which symbols can not be internalized
applyScopeRestrictions();
// create output file
std::string ErrInfo;
tool_output_file Out(path, ErrInfo,
raw_fd_ostream::F_Binary);
if (!ErrInfo.empty()) {
errMsg = "could not open bitcode file for writing: ";
errMsg += path;
return true;
}
// write bitcode to it
WriteBitcodeToFile(_linker.getModule(), Out.os());
Out.os().close();
if (Out.os().has_error()) {
errMsg = "could not write bitcode file: ";
errMsg += path;
Out.os().clear_error();
return true;
}
Out.keep();
return false;
}
bool LTOCodeGenerator::compile_to_file(const char** name, std::string& errMsg)
{
// make unique temp .o file to put generated object file
sys::PathWithStatus uniqueObjPath("lto-llvm.o");
if ( uniqueObjPath.createTemporaryFileOnDisk(false, &errMsg) ) {
uniqueObjPath.eraseFromDisk();
return true;
}
sys::RemoveFileOnSignal(uniqueObjPath);
// generate object file
bool genResult = false;
tool_output_file objFile(uniqueObjPath.c_str(), errMsg);
if (!errMsg.empty())
return true;
genResult = this->generateObjectFile(objFile.os(), errMsg);
objFile.os().close();
if (objFile.os().has_error()) {
objFile.os().clear_error();
return true;
}
objFile.keep();
if ( genResult ) {
uniqueObjPath.eraseFromDisk();
return true;
}
_nativeObjectPath = uniqueObjPath.str();
*name = _nativeObjectPath.c_str();
return false;
}
const void* LTOCodeGenerator::compile(size_t* length, std::string& errMsg)
{
const char *name;
if (compile_to_file(&name, errMsg))
return NULL;
// remove old buffer if compile() called twice
delete _nativeObjectFile;
// read .o file into memory buffer
OwningPtr<MemoryBuffer> BuffPtr;
if (error_code ec = MemoryBuffer::getFile(name, BuffPtr, -1, false)) {
errMsg = ec.message();
return NULL;
}
_nativeObjectFile = BuffPtr.take();
// remove temp files
sys::Path(_nativeObjectPath).eraseFromDisk();
// return buffer, unless error
if ( _nativeObjectFile == NULL )
return NULL;
*length = _nativeObjectFile->getBufferSize();
return _nativeObjectFile->getBufferStart();
}
bool LTOCodeGenerator::determineTarget(std::string& errMsg)
{
if ( _target == NULL ) {
std::string Triple = _linker.getModule()->getTargetTriple();
if (Triple.empty())
Triple = sys::getDefaultTargetTriple();
// create target machine from info for merged modules
const Target *march = TargetRegistry::lookupTarget(Triple, errMsg);
if ( march == NULL )
return true;
// The relocation model is actually a static member of TargetMachine
// and needs to be set before the TargetMachine is instantiated.
Reloc::Model RelocModel = Reloc::Default;
switch( _codeModel ) {
case LTO_CODEGEN_PIC_MODEL_STATIC:
RelocModel = Reloc::Static;
break;
case LTO_CODEGEN_PIC_MODEL_DYNAMIC:
RelocModel = Reloc::PIC_;
break;
case LTO_CODEGEN_PIC_MODEL_DYNAMIC_NO_PIC:
RelocModel = Reloc::DynamicNoPIC;
break;
}
// construct LTOModule, hand over ownership of module and target
SubtargetFeatures Features;
Features.getDefaultSubtargetFeatures(llvm::Triple(Triple));
std::string FeatureStr = Features.getString();
TargetOptions Options;
_target = march->createTargetMachine(Triple, _mCpu, FeatureStr, Options,
RelocModel);
}
return false;
}
void LTOCodeGenerator::applyRestriction(GlobalValue &GV,
std::vector<const char*> &mustPreserveList,
SmallPtrSet<GlobalValue*, 8> &asmUsed,
Mangler &mangler) {
SmallString<64> Buffer;
mangler.getNameWithPrefix(Buffer, &GV, false);
if (GV.isDeclaration())
return;
if (_mustPreserveSymbols.count(Buffer))
mustPreserveList.push_back(GV.getName().data());
if (_asmUndefinedRefs.count(Buffer))
asmUsed.insert(&GV);
}
static void findUsedValues(GlobalVariable *LLVMUsed,
SmallPtrSet<GlobalValue*, 8> &UsedValues) {
if (LLVMUsed == 0) return;
ConstantArray *Inits = dyn_cast<ConstantArray>(LLVMUsed->getInitializer());
if (Inits == 0) return;
for (unsigned i = 0, e = Inits->getNumOperands(); i != e; ++i)
if (GlobalValue *GV =
dyn_cast<GlobalValue>(Inits->getOperand(i)->stripPointerCasts()))
UsedValues.insert(GV);
}
void LTOCodeGenerator::applyScopeRestrictions() {
if (_scopeRestrictionsDone) return;
Module *mergedModule = _linker.getModule();
// Start off with a verification pass.
PassManager passes;
passes.add(createVerifierPass());
// mark which symbols can not be internalized
MCContext Context(*_target->getMCAsmInfo(), *_target->getRegisterInfo(), NULL);
Mangler mangler(Context, *_target->getTargetData());
std::vector<const char*> mustPreserveList;
SmallPtrSet<GlobalValue*, 8> asmUsed;
for (Module::iterator f = mergedModule->begin(),
e = mergedModule->end(); f != e; ++f)
applyRestriction(*f, mustPreserveList, asmUsed, mangler);
for (Module::global_iterator v = mergedModule->global_begin(),
e = mergedModule->global_end(); v != e; ++v)
applyRestriction(*v, mustPreserveList, asmUsed, mangler);
for (Module::alias_iterator a = mergedModule->alias_begin(),
e = mergedModule->alias_end(); a != e; ++a)
applyRestriction(*a, mustPreserveList, asmUsed, mangler);
GlobalVariable *LLVMCompilerUsed =
mergedModule->getGlobalVariable("llvm.compiler.used");
findUsedValues(LLVMCompilerUsed, asmUsed);
if (LLVMCompilerUsed)
LLVMCompilerUsed->eraseFromParent();
llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(_context);
std::vector<Constant*> asmUsed2;
for (SmallPtrSet<GlobalValue*, 16>::const_iterator i = asmUsed.begin(),
e = asmUsed.end(); i !=e; ++i) {
GlobalValue *GV = *i;
Constant *c = ConstantExpr::getBitCast(GV, i8PTy);
asmUsed2.push_back(c);
}
llvm::ArrayType *ATy = llvm::ArrayType::get(i8PTy, asmUsed2.size());
LLVMCompilerUsed =
new llvm::GlobalVariable(*mergedModule, ATy, false,
llvm::GlobalValue::AppendingLinkage,
llvm::ConstantArray::get(ATy, asmUsed2),
"llvm.compiler.used");
LLVMCompilerUsed->setSection("llvm.metadata");
passes.add(createInternalizePass(mustPreserveList));
// apply scope restrictions
passes.run(*mergedModule);
_scopeRestrictionsDone = true;
}
/// Optimize merged modules using various IPO passes
bool LTOCodeGenerator::generateObjectFile(raw_ostream &out,
std::string &errMsg) {
if ( this->determineTarget(errMsg) )
return true;
// mark which symbols can not be internalized
this->applyScopeRestrictions();
Module* mergedModule = _linker.getModule();
// if options were requested, set them
if ( !_codegenOptions.empty() )
cl::ParseCommandLineOptions(_codegenOptions.size(),
const_cast<char **>(&_codegenOptions[0]));
// Instantiate the pass manager to organize the passes.
PassManager passes;
// Start off with a verification pass.
passes.add(createVerifierPass());
// Add an appropriate TargetData instance for this module...
passes.add(new TargetData(*_target->getTargetData()));
PassManagerBuilder().populateLTOPassManager(passes, /*Internalize=*/ false,
!DisableInline);
// Make sure everything is still good.
passes.add(createVerifierPass());
FunctionPassManager *codeGenPasses = new FunctionPassManager(mergedModule);
codeGenPasses->add(new TargetData(*_target->getTargetData()));
formatted_raw_ostream Out(out);
if (_target->addPassesToEmitFile(*codeGenPasses, Out,
TargetMachine::CGFT_ObjectFile,
CodeGenOpt::Aggressive)) {
errMsg = "target file type not supported";
return true;
}
// Run our queue of passes all at once now, efficiently.
passes.run(*mergedModule);
// Run the code generator, and write assembly file
codeGenPasses->doInitialization();
for (Module::iterator
it = mergedModule->begin(), e = mergedModule->end(); it != e; ++it)
if (!it->isDeclaration())
codeGenPasses->run(*it);
codeGenPasses->doFinalization();
delete codeGenPasses;
return false; // success
}
/// Optimize merged modules using various IPO passes
void LTOCodeGenerator::setCodeGenDebugOptions(const char* options)
{
for (std::pair<StringRef, StringRef> o = getToken(options);
!o.first.empty(); o = getToken(o.second)) {
// ParseCommandLineOptions() expects argv[0] to be program name.
// Lazily add that.
if ( _codegenOptions.empty() )
_codegenOptions.push_back("libLTO");
_codegenOptions.push_back(strdup(o.first.str().c_str()));
}
}