llvm-6502/lib/LTO/LTOCodeGenerator.cpp
Chandler Carruth bda134910a [PM] Move TargetLibraryInfo into the Analysis library.
While the term "Target" is in the name, it doesn't really have to do
with the LLVM Target library -- this isn't an abstraction which LLVM
targets generally need to implement or extend. It has much more to do
with modeling the various runtime libraries on different OSes and with
different runtime environments. The "target" in this sense is the more
general sense of a target of cross compilation.

This is in preparation for porting this analysis to the new pass
manager.

No functionality changed, and updates inbound for Clang and Polly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226078 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-15 02:16:27 +00:00

587 lines
19 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 "llvm/LTO/LTOCodeGenerator.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Analysis/Passes.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Bitcode/ReaderWriter.h"
#include "llvm/CodeGen/RuntimeLibcalls.h"
#include "llvm/Config/config.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/IR/DiagnosticPrinter.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Mangler.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Verifier.h"
#include "llvm/InitializePasses.h"
#include "llvm/LTO/LTOModule.h"
#include "llvm/Linker/Linker.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/SubtargetFeature.h"
#include "llvm/PassManager.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/FormattedStream.h"
#include "llvm/Support/Host.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Signals.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/TargetSelect.h"
#include "llvm/Support/ToolOutputFile.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Target/TargetSubtargetInfo.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/IPO/PassManagerBuilder.h"
#include "llvm/Transforms/ObjCARC.h"
#include <system_error>
using namespace llvm;
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()), IRLinker(new Module("ld-temp.o", Context)) {
initialize();
}
LTOCodeGenerator::LTOCodeGenerator(std::unique_ptr<LLVMContext> Context)
: OwnedContext(std::move(Context)), Context(*OwnedContext),
IRLinker(new Module("ld-temp.o", *OwnedContext)) {
initialize();
}
void LTOCodeGenerator::initialize() {
TargetMach = nullptr;
EmitDwarfDebugInfo = false;
ScopeRestrictionsDone = false;
CodeModel = LTO_CODEGEN_PIC_MODEL_DEFAULT;
DiagHandler = nullptr;
DiagContext = nullptr;
initializeLTOPasses();
}
LTOCodeGenerator::~LTOCodeGenerator() {
delete TargetMach;
TargetMach = nullptr;
IRLinker.deleteModule();
for (std::vector<char *>::iterator I = CodegenOptions.begin(),
E = CodegenOptions.end();
I != E; ++I)
free(*I);
}
// Initialize LTO passes. Please keep this funciton in sync with
// PassManagerBuilder::populateLTOPassManager(), and make sure all LTO
// passes are initialized.
void LTOCodeGenerator::initializeLTOPasses() {
PassRegistry &R = *PassRegistry::getPassRegistry();
initializeInternalizePassPass(R);
initializeIPSCCPPass(R);
initializeGlobalOptPass(R);
initializeConstantMergePass(R);
initializeDAHPass(R);
initializeInstCombinerPass(R);
initializeSimpleInlinerPass(R);
initializePruneEHPass(R);
initializeGlobalDCEPass(R);
initializeArgPromotionPass(R);
initializeJumpThreadingPass(R);
initializeSROAPass(R);
initializeSROA_DTPass(R);
initializeSROA_SSAUpPass(R);
initializeFunctionAttrsPass(R);
initializeGlobalsModRefPass(R);
initializeLICMPass(R);
initializeMergedLoadStoreMotionPass(R);
initializeGVNPass(R);
initializeMemCpyOptPass(R);
initializeDCEPass(R);
initializeCFGSimplifyPassPass(R);
}
bool LTOCodeGenerator::addModule(LTOModule *mod) {
assert(&mod->getModule().getContext() == &Context &&
"Expected module in same context");
bool ret = IRLinker.linkInModule(&mod->getModule());
const std::vector<const char*> &undefs = mod->getAsmUndefinedRefs();
for (int i = 0, e = undefs.size(); i != e; ++i)
AsmUndefinedRefs[undefs[i]] = 1;
return !ret;
}
void LTOCodeGenerator::setTargetOptions(TargetOptions options) {
Options = options;
}
void LTOCodeGenerator::setDebugInfo(lto_debug_model debug) {
switch (debug) {
case LTO_DEBUG_MODEL_NONE:
EmitDwarfDebugInfo = false;
return;
case LTO_DEBUG_MODEL_DWARF:
EmitDwarfDebugInfo = true;
return;
}
llvm_unreachable("Unknown debug format!");
}
void LTOCodeGenerator::setCodePICModel(lto_codegen_model model) {
switch (model) {
case LTO_CODEGEN_PIC_MODEL_STATIC:
case LTO_CODEGEN_PIC_MODEL_DYNAMIC:
case LTO_CODEGEN_PIC_MODEL_DYNAMIC_NO_PIC:
case LTO_CODEGEN_PIC_MODEL_DEFAULT:
CodeModel = model;
return;
}
llvm_unreachable("Unknown PIC model!");
}
bool LTOCodeGenerator::writeMergedModules(const char *path,
std::string &errMsg) {
if (!determineTarget(errMsg))
return false;
// mark which symbols can not be internalized
applyScopeRestrictions();
// create output file
std::error_code EC;
tool_output_file Out(path, EC, sys::fs::F_None);
if (EC) {
errMsg = "could not open bitcode file for writing: ";
errMsg += path;
return false;
}
// write bitcode to it
WriteBitcodeToFile(IRLinker.getModule(), Out.os());
Out.os().close();
if (Out.os().has_error()) {
errMsg = "could not write bitcode file: ";
errMsg += path;
Out.os().clear_error();
return false;
}
Out.keep();
return true;
}
bool LTOCodeGenerator::compile_to_file(const char** name,
bool disableOpt,
bool disableInline,
bool disableGVNLoadPRE,
bool disableVectorization,
std::string& errMsg) {
// make unique temp .o file to put generated object file
SmallString<128> Filename;
int FD;
std::error_code EC =
sys::fs::createTemporaryFile("lto-llvm", "o", FD, Filename);
if (EC) {
errMsg = EC.message();
return false;
}
// generate object file
tool_output_file objFile(Filename.c_str(), FD);
bool genResult =
generateObjectFile(objFile.os(), disableOpt, disableInline,
disableGVNLoadPRE, disableVectorization, errMsg);
objFile.os().close();
if (objFile.os().has_error()) {
objFile.os().clear_error();
sys::fs::remove(Twine(Filename));
return false;
}
objFile.keep();
if (!genResult) {
sys::fs::remove(Twine(Filename));
return false;
}
NativeObjectPath = Filename.c_str();
*name = NativeObjectPath.c_str();
return true;
}
const void* LTOCodeGenerator::compile(size_t* length,
bool disableOpt,
bool disableInline,
bool disableGVNLoadPRE,
bool disableVectorization,
std::string& errMsg) {
const char *name;
if (!compile_to_file(&name, disableOpt, disableInline, disableGVNLoadPRE,
disableVectorization, errMsg))
return nullptr;
// read .o file into memory buffer
ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOrErr =
MemoryBuffer::getFile(name, -1, false);
if (std::error_code EC = BufferOrErr.getError()) {
errMsg = EC.message();
sys::fs::remove(NativeObjectPath);
return nullptr;
}
NativeObjectFile = std::move(*BufferOrErr);
// remove temp files
sys::fs::remove(NativeObjectPath);
// return buffer, unless error
if (!NativeObjectFile)
return nullptr;
*length = NativeObjectFile->getBufferSize();
return NativeObjectFile->getBufferStart();
}
bool LTOCodeGenerator::determineTarget(std::string &errMsg) {
if (TargetMach)
return true;
std::string TripleStr = IRLinker.getModule()->getTargetTriple();
if (TripleStr.empty())
TripleStr = sys::getDefaultTargetTriple();
llvm::Triple Triple(TripleStr);
// create target machine from info for merged modules
const Target *march = TargetRegistry::lookupTarget(TripleStr, errMsg);
if (!march)
return false;
// 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;
case LTO_CODEGEN_PIC_MODEL_DEFAULT:
// RelocModel is already the default, so leave it that way.
break;
}
// Construct LTOModule, hand over ownership of module and target. Use MAttr as
// the default set of features.
SubtargetFeatures Features(MAttr);
Features.getDefaultSubtargetFeatures(Triple);
std::string FeatureStr = Features.getString();
// Set a default CPU for Darwin triples.
if (MCpu.empty() && Triple.isOSDarwin()) {
if (Triple.getArch() == llvm::Triple::x86_64)
MCpu = "core2";
else if (Triple.getArch() == llvm::Triple::x86)
MCpu = "yonah";
else if (Triple.getArch() == llvm::Triple::aarch64)
MCpu = "cyclone";
}
TargetMach = march->createTargetMachine(TripleStr, MCpu, FeatureStr, Options,
RelocModel, CodeModel::Default,
CodeGenOpt::Aggressive);
return true;
}
void LTOCodeGenerator::
applyRestriction(GlobalValue &GV,
ArrayRef<StringRef> Libcalls,
std::vector<const char*> &MustPreserveList,
SmallPtrSetImpl<GlobalValue*> &AsmUsed,
Mangler &Mangler) {
// There are no restrictions to apply to declarations.
if (GV.isDeclaration())
return;
// There is nothing more restrictive than private linkage.
if (GV.hasPrivateLinkage())
return;
SmallString<64> Buffer;
TargetMach->getNameWithPrefix(Buffer, &GV, Mangler);
if (MustPreserveSymbols.count(Buffer))
MustPreserveList.push_back(GV.getName().data());
if (AsmUndefinedRefs.count(Buffer))
AsmUsed.insert(&GV);
// Conservatively append user-supplied runtime library functions to
// llvm.compiler.used. These could be internalized and deleted by
// optimizations like -globalopt, causing problems when later optimizations
// add new library calls (e.g., llvm.memset => memset and printf => puts).
// Leave it to the linker to remove any dead code (e.g. with -dead_strip).
if (isa<Function>(GV) &&
std::binary_search(Libcalls.begin(), Libcalls.end(), GV.getName()))
AsmUsed.insert(&GV);
}
static void findUsedValues(GlobalVariable *LLVMUsed,
SmallPtrSetImpl<GlobalValue*> &UsedValues) {
if (!LLVMUsed) return;
ConstantArray *Inits = cast<ConstantArray>(LLVMUsed->getInitializer());
for (unsigned i = 0, e = Inits->getNumOperands(); i != e; ++i)
if (GlobalValue *GV =
dyn_cast<GlobalValue>(Inits->getOperand(i)->stripPointerCasts()))
UsedValues.insert(GV);
}
static void accumulateAndSortLibcalls(std::vector<StringRef> &Libcalls,
const TargetLibraryInfo& TLI,
const TargetLowering *Lowering)
{
// TargetLibraryInfo has info on C runtime library calls on the current
// target.
for (unsigned I = 0, E = static_cast<unsigned>(LibFunc::NumLibFuncs);
I != E; ++I) {
LibFunc::Func F = static_cast<LibFunc::Func>(I);
if (TLI.has(F))
Libcalls.push_back(TLI.getName(F));
}
// TargetLowering has info on library calls that CodeGen expects to be
// available, both from the C runtime and compiler-rt.
if (Lowering)
for (unsigned I = 0, E = static_cast<unsigned>(RTLIB::UNKNOWN_LIBCALL);
I != E; ++I)
if (const char *Name
= Lowering->getLibcallName(static_cast<RTLIB::Libcall>(I)))
Libcalls.push_back(Name);
array_pod_sort(Libcalls.begin(), Libcalls.end());
Libcalls.erase(std::unique(Libcalls.begin(), Libcalls.end()),
Libcalls.end());
}
void LTOCodeGenerator::applyScopeRestrictions() {
if (ScopeRestrictionsDone)
return;
Module *mergedModule = IRLinker.getModule();
// Start off with a verification pass.
PassManager passes;
passes.add(createVerifierPass());
passes.add(createDebugInfoVerifierPass());
// mark which symbols can not be internalized
Mangler Mangler(TargetMach->getSubtargetImpl()->getDataLayout());
std::vector<const char*> MustPreserveList;
SmallPtrSet<GlobalValue*, 8> AsmUsed;
std::vector<StringRef> Libcalls;
TargetLibraryInfo TLI(Triple(TargetMach->getTargetTriple()));
accumulateAndSortLibcalls(
Libcalls, TLI, TargetMach->getSubtargetImpl()->getTargetLowering());
for (Module::iterator f = mergedModule->begin(),
e = mergedModule->end(); f != e; ++f)
applyRestriction(*f, Libcalls, MustPreserveList, AsmUsed, Mangler);
for (Module::global_iterator v = mergedModule->global_begin(),
e = mergedModule->global_end(); v != e; ++v)
applyRestriction(*v, Libcalls, MustPreserveList, AsmUsed, Mangler);
for (Module::alias_iterator a = mergedModule->alias_begin(),
e = mergedModule->alias_end(); a != e; ++a)
applyRestriction(*a, Libcalls, MustPreserveList, AsmUsed, Mangler);
GlobalVariable *LLVMCompilerUsed =
mergedModule->getGlobalVariable("llvm.compiler.used");
findUsedValues(LLVMCompilerUsed, AsmUsed);
if (LLVMCompilerUsed)
LLVMCompilerUsed->eraseFromParent();
if (!AsmUsed.empty()) {
llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(Context);
std::vector<Constant*> asmUsed2;
for (auto *GV : AsmUsed) {
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,
bool DisableOpt,
bool DisableInline,
bool DisableGVNLoadPRE,
bool DisableVectorization,
std::string &errMsg) {
if (!this->determineTarget(errMsg))
return false;
Module *mergedModule = IRLinker.getModule();
// Mark which symbols can not be internalized
this->applyScopeRestrictions();
// Instantiate the pass manager to organize the passes.
PassManager passes;
// Add an appropriate DataLayout instance for this module...
mergedModule->setDataLayout(TargetMach->getSubtargetImpl()->getDataLayout());
Triple TargetTriple(TargetMach->getTargetTriple());
PassManagerBuilder PMB;
PMB.DisableGVNLoadPRE = DisableGVNLoadPRE;
PMB.LoopVectorize = !DisableVectorization;
PMB.SLPVectorize = !DisableVectorization;
if (!DisableInline)
PMB.Inliner = createFunctionInliningPass();
PMB.LibraryInfo = new TargetLibraryInfo(TargetTriple);
if (DisableOpt)
PMB.OptLevel = 0;
PMB.VerifyInput = true;
PMB.VerifyOutput = true;
PMB.populateLTOPassManager(passes, TargetMach);
PassManager codeGenPasses;
codeGenPasses.add(new DataLayoutPass());
formatted_raw_ostream Out(out);
// If the bitcode files contain ARC code and were compiled with optimization,
// the ObjCARCContractPass must be run, so do it unconditionally here.
codeGenPasses.add(createObjCARCContractPass());
if (TargetMach->addPassesToEmitFile(codeGenPasses, Out,
TargetMachine::CGFT_ObjectFile)) {
errMsg = "target file type not supported";
return false;
}
// Run our queue of passes all at once now, efficiently.
passes.run(*mergedModule);
// Run the code generator, and write assembly file
codeGenPasses.run(*mergedModule);
return true;
}
/// setCodeGenDebugOptions - Set codegen debugging options to aid in debugging
/// LTO problems.
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(strdup("libLLVMLTO"));
CodegenOptions.push_back(strdup(o.first.str().c_str()));
}
}
void LTOCodeGenerator::parseCodeGenDebugOptions() {
// if options were requested, set them
if (!CodegenOptions.empty())
cl::ParseCommandLineOptions(CodegenOptions.size(),
const_cast<char **>(&CodegenOptions[0]));
}
void LTOCodeGenerator::DiagnosticHandler(const DiagnosticInfo &DI,
void *Context) {
((LTOCodeGenerator *)Context)->DiagnosticHandler2(DI);
}
void LTOCodeGenerator::DiagnosticHandler2(const DiagnosticInfo &DI) {
// Map the LLVM internal diagnostic severity to the LTO diagnostic severity.
lto_codegen_diagnostic_severity_t Severity;
switch (DI.getSeverity()) {
case DS_Error:
Severity = LTO_DS_ERROR;
break;
case DS_Warning:
Severity = LTO_DS_WARNING;
break;
case DS_Remark:
Severity = LTO_DS_REMARK;
break;
case DS_Note:
Severity = LTO_DS_NOTE;
break;
}
// Create the string that will be reported to the external diagnostic handler.
std::string MsgStorage;
raw_string_ostream Stream(MsgStorage);
DiagnosticPrinterRawOStream DP(Stream);
DI.print(DP);
Stream.flush();
// If this method has been called it means someone has set up an external
// diagnostic handler. Assert on that.
assert(DiagHandler && "Invalid diagnostic handler");
(*DiagHandler)(Severity, MsgStorage.c_str(), DiagContext);
}
void
LTOCodeGenerator::setDiagnosticHandler(lto_diagnostic_handler_t DiagHandler,
void *Ctxt) {
this->DiagHandler = DiagHandler;
this->DiagContext = Ctxt;
if (!DiagHandler)
return Context.setDiagnosticHandler(nullptr, nullptr);
// Register the LTOCodeGenerator stub in the LLVMContext to forward the
// diagnostic to the external DiagHandler.
Context.setDiagnosticHandler(LTOCodeGenerator::DiagnosticHandler, this,
/* RespectFilters */ true);
}