1 //===-LTOCodeGenerator.cpp - LLVM Link Time Optimizer ---------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the Link Time Optimization library. This library is
11 // intended to be used by linker to optimize code at link time.
13 //===----------------------------------------------------------------------===//
15 #include "llvm/LTO/LTOCodeGenerator.h"
16 #include "llvm/ADT/StringExtras.h"
17 #include "llvm/Analysis/Passes.h"
18 #include "llvm/Bitcode/ReaderWriter.h"
19 #include "llvm/CodeGen/RuntimeLibcalls.h"
20 #include "llvm/Config/config.h"
21 #include "llvm/IR/Constants.h"
22 #include "llvm/IR/DataLayout.h"
23 #include "llvm/IR/DerivedTypes.h"
24 #include "llvm/IR/DiagnosticInfo.h"
25 #include "llvm/IR/DiagnosticPrinter.h"
26 #include "llvm/IR/LLVMContext.h"
27 #include "llvm/IR/Mangler.h"
28 #include "llvm/IR/Module.h"
29 #include "llvm/IR/Verifier.h"
30 #include "llvm/InitializePasses.h"
31 #include "llvm/LTO/LTOModule.h"
32 #include "llvm/Linker/Linker.h"
33 #include "llvm/MC/MCAsmInfo.h"
34 #include "llvm/MC/MCContext.h"
35 #include "llvm/MC/SubtargetFeature.h"
36 #include "llvm/PassManager.h"
37 #include "llvm/Support/CommandLine.h"
38 #include "llvm/Support/FileSystem.h"
39 #include "llvm/Support/FormattedStream.h"
40 #include "llvm/Support/Host.h"
41 #include "llvm/Support/MemoryBuffer.h"
42 #include "llvm/Support/Signals.h"
43 #include "llvm/Support/TargetRegistry.h"
44 #include "llvm/Support/TargetSelect.h"
45 #include "llvm/Support/ToolOutputFile.h"
46 #include "llvm/Support/raw_ostream.h"
47 #include "llvm/Support/system_error.h"
48 #include "llvm/Target/TargetLibraryInfo.h"
49 #include "llvm/Target/TargetLowering.h"
50 #include "llvm/Target/TargetOptions.h"
51 #include "llvm/Target/TargetRegisterInfo.h"
52 #include "llvm/Transforms/IPO.h"
53 #include "llvm/Transforms/IPO/PassManagerBuilder.h"
54 #include "llvm/Transforms/ObjCARC.h"
57 const char* LTOCodeGenerator::getVersionString() {
58 #ifdef LLVM_VERSION_INFO
59 return PACKAGE_NAME " version " PACKAGE_VERSION ", " LLVM_VERSION_INFO;
61 return PACKAGE_NAME " version " PACKAGE_VERSION;
65 LTOCodeGenerator::LTOCodeGenerator()
66 : Context(getGlobalContext()), Linker(new Module("ld-temp.o", Context)),
67 TargetMach(NULL), EmitDwarfDebugInfo(false), ScopeRestrictionsDone(false),
68 CodeModel(LTO_CODEGEN_PIC_MODEL_DYNAMIC),
69 InternalizeStrategy(LTO_INTERNALIZE_FULL), NativeObjectFile(NULL),
70 DiagHandler(NULL), DiagContext(NULL) {
71 initializeLTOPasses();
74 LTOCodeGenerator::~LTOCodeGenerator() {
76 delete NativeObjectFile;
78 NativeObjectFile = NULL;
80 Linker.deleteModule();
82 for (std::vector<char *>::iterator I = CodegenOptions.begin(),
83 E = CodegenOptions.end();
88 // Initialize LTO passes. Please keep this funciton in sync with
89 // PassManagerBuilder::populateLTOPassManager(), and make sure all LTO
90 // passes are initialized.
91 void LTOCodeGenerator::initializeLTOPasses() {
92 PassRegistry &R = *PassRegistry::getPassRegistry();
94 initializeInternalizePassPass(R);
95 initializeIPSCCPPass(R);
96 initializeGlobalOptPass(R);
97 initializeConstantMergePass(R);
99 initializeInstCombinerPass(R);
100 initializeSimpleInlinerPass(R);
101 initializePruneEHPass(R);
102 initializeGlobalDCEPass(R);
103 initializeArgPromotionPass(R);
104 initializeJumpThreadingPass(R);
105 initializeSROAPass(R);
106 initializeSROA_DTPass(R);
107 initializeSROA_SSAUpPass(R);
108 initializeFunctionAttrsPass(R);
109 initializeGlobalsModRefPass(R);
110 initializeLICMPass(R);
111 initializeGVNPass(R);
112 initializeMemCpyOptPass(R);
113 initializeDCEPass(R);
114 initializeCFGSimplifyPassPass(R);
117 bool LTOCodeGenerator::addModule(LTOModule* mod, std::string& errMsg) {
118 bool ret = Linker.linkInModule(mod->getLLVVMModule(), &errMsg);
120 const std::vector<const char*> &undefs = mod->getAsmUndefinedRefs();
121 for (int i = 0, e = undefs.size(); i != e; ++i)
122 AsmUndefinedRefs[undefs[i]] = 1;
127 void LTOCodeGenerator::setTargetOptions(TargetOptions options) {
128 Options.LessPreciseFPMADOption = options.LessPreciseFPMADOption;
129 Options.NoFramePointerElim = options.NoFramePointerElim;
130 Options.AllowFPOpFusion = options.AllowFPOpFusion;
131 Options.UnsafeFPMath = options.UnsafeFPMath;
132 Options.NoInfsFPMath = options.NoInfsFPMath;
133 Options.NoNaNsFPMath = options.NoNaNsFPMath;
134 Options.HonorSignDependentRoundingFPMathOption =
135 options.HonorSignDependentRoundingFPMathOption;
136 Options.UseSoftFloat = options.UseSoftFloat;
137 Options.FloatABIType = options.FloatABIType;
138 Options.NoZerosInBSS = options.NoZerosInBSS;
139 Options.GuaranteedTailCallOpt = options.GuaranteedTailCallOpt;
140 Options.DisableTailCalls = options.DisableTailCalls;
141 Options.StackAlignmentOverride = options.StackAlignmentOverride;
142 Options.TrapFuncName = options.TrapFuncName;
143 Options.PositionIndependentExecutable = options.PositionIndependentExecutable;
144 Options.EnableSegmentedStacks = options.EnableSegmentedStacks;
145 Options.UseInitArray = options.UseInitArray;
148 void LTOCodeGenerator::setDebugInfo(lto_debug_model debug) {
150 case LTO_DEBUG_MODEL_NONE:
151 EmitDwarfDebugInfo = false;
154 case LTO_DEBUG_MODEL_DWARF:
155 EmitDwarfDebugInfo = true;
158 llvm_unreachable("Unknown debug format!");
161 void LTOCodeGenerator::setCodePICModel(lto_codegen_model model) {
163 case LTO_CODEGEN_PIC_MODEL_STATIC:
164 case LTO_CODEGEN_PIC_MODEL_DYNAMIC:
165 case LTO_CODEGEN_PIC_MODEL_DYNAMIC_NO_PIC:
169 llvm_unreachable("Unknown PIC model!");
173 LTOCodeGenerator::setInternalizeStrategy(lto_internalize_strategy Strategy) {
175 case LTO_INTERNALIZE_FULL:
176 case LTO_INTERNALIZE_NONE:
177 case LTO_INTERNALIZE_HIDDEN:
178 InternalizeStrategy = Strategy;
181 llvm_unreachable("Unknown internalize strategy!");
184 bool LTOCodeGenerator::writeMergedModules(const char *path,
185 std::string &errMsg) {
186 if (!determineTarget(errMsg))
189 // mark which symbols can not be internalized
190 applyScopeRestrictions();
192 // create output file
194 tool_output_file Out(path, ErrInfo, sys::fs::F_None);
195 if (!ErrInfo.empty()) {
196 errMsg = "could not open bitcode file for writing: ";
201 // write bitcode to it
202 WriteBitcodeToFile(Linker.getModule(), Out.os());
205 if (Out.os().has_error()) {
206 errMsg = "could not write bitcode file: ";
208 Out.os().clear_error();
216 bool LTOCodeGenerator::compile_to_file(const char** name,
219 bool disableGVNLoadPRE,
220 std::string& errMsg) {
221 // make unique temp .o file to put generated object file
222 SmallString<128> Filename;
224 error_code EC = sys::fs::createTemporaryFile("lto-llvm", "o", FD, Filename);
226 errMsg = EC.message();
230 // generate object file
231 tool_output_file objFile(Filename.c_str(), FD);
233 bool genResult = generateObjectFile(objFile.os(), disableOpt, disableInline,
234 disableGVNLoadPRE, errMsg);
235 objFile.os().close();
236 if (objFile.os().has_error()) {
237 objFile.os().clear_error();
238 sys::fs::remove(Twine(Filename));
244 sys::fs::remove(Twine(Filename));
248 NativeObjectPath = Filename.c_str();
249 *name = NativeObjectPath.c_str();
253 const void* LTOCodeGenerator::compile(size_t* length,
256 bool disableGVNLoadPRE,
257 std::string& errMsg) {
259 if (!compile_to_file(&name, disableOpt, disableInline, disableGVNLoadPRE,
263 // remove old buffer if compile() called twice
264 delete NativeObjectFile;
266 // read .o file into memory buffer
267 std::unique_ptr<MemoryBuffer> BuffPtr;
268 if (error_code ec = MemoryBuffer::getFile(name, BuffPtr, -1, false)) {
269 errMsg = ec.message();
270 sys::fs::remove(NativeObjectPath);
273 NativeObjectFile = BuffPtr.release();
276 sys::fs::remove(NativeObjectPath);
278 // return buffer, unless error
279 if (NativeObjectFile == NULL)
281 *length = NativeObjectFile->getBufferSize();
282 return NativeObjectFile->getBufferStart();
285 bool LTOCodeGenerator::determineTarget(std::string &errMsg) {
286 if (TargetMach != NULL)
289 std::string TripleStr = Linker.getModule()->getTargetTriple();
290 if (TripleStr.empty())
291 TripleStr = sys::getDefaultTargetTriple();
292 llvm::Triple Triple(TripleStr);
294 // create target machine from info for merged modules
295 const Target *march = TargetRegistry::lookupTarget(TripleStr, errMsg);
299 // The relocation model is actually a static member of TargetMachine and
300 // needs to be set before the TargetMachine is instantiated.
301 Reloc::Model RelocModel = Reloc::Default;
303 case LTO_CODEGEN_PIC_MODEL_STATIC:
304 RelocModel = Reloc::Static;
306 case LTO_CODEGEN_PIC_MODEL_DYNAMIC:
307 RelocModel = Reloc::PIC_;
309 case LTO_CODEGEN_PIC_MODEL_DYNAMIC_NO_PIC:
310 RelocModel = Reloc::DynamicNoPIC;
314 // construct LTOModule, hand over ownership of module and target
315 SubtargetFeatures Features;
316 Features.getDefaultSubtargetFeatures(Triple);
317 std::string FeatureStr = Features.getString();
318 // Set a default CPU for Darwin triples.
319 if (MCpu.empty() && Triple.isOSDarwin()) {
320 if (Triple.getArch() == llvm::Triple::x86_64)
322 else if (Triple.getArch() == llvm::Triple::x86)
326 TargetMach = march->createTargetMachine(TripleStr, MCpu, FeatureStr, Options,
327 RelocModel, CodeModel::Default,
328 CodeGenOpt::Aggressive);
332 void LTOCodeGenerator::
333 applyRestriction(GlobalValue &GV,
334 const ArrayRef<StringRef> &Libcalls,
335 std::vector<const char*> &MustPreserveList,
336 SmallPtrSet<GlobalValue*, 8> &AsmUsed,
338 // There are no restrictions to apply to declarations.
339 if (GV.isDeclaration())
342 // There is nothing more restrictive than private linkage.
343 if (GV.hasPrivateLinkage())
346 SmallString<64> Buffer;
347 TargetMach->getNameWithPrefix(Buffer, &GV, Mangler);
349 if (MustPreserveSymbols.count(Buffer))
350 MustPreserveList.push_back(GV.getName().data());
351 if (AsmUndefinedRefs.count(Buffer))
354 // Conservatively append user-supplied runtime library functions to
355 // llvm.compiler.used. These could be internalized and deleted by
356 // optimizations like -globalopt, causing problems when later optimizations
357 // add new library calls (e.g., llvm.memset => memset and printf => puts).
358 // Leave it to the linker to remove any dead code (e.g. with -dead_strip).
359 if (isa<Function>(GV) &&
360 std::binary_search(Libcalls.begin(), Libcalls.end(), GV.getName()))
364 static void findUsedValues(GlobalVariable *LLVMUsed,
365 SmallPtrSet<GlobalValue*, 8> &UsedValues) {
366 if (LLVMUsed == 0) return;
368 ConstantArray *Inits = cast<ConstantArray>(LLVMUsed->getInitializer());
369 for (unsigned i = 0, e = Inits->getNumOperands(); i != e; ++i)
370 if (GlobalValue *GV =
371 dyn_cast<GlobalValue>(Inits->getOperand(i)->stripPointerCasts()))
372 UsedValues.insert(GV);
375 static void accumulateAndSortLibcalls(std::vector<StringRef> &Libcalls,
376 const TargetLibraryInfo& TLI,
377 const TargetLowering *Lowering)
379 // TargetLibraryInfo has info on C runtime library calls on the current
381 for (unsigned I = 0, E = static_cast<unsigned>(LibFunc::NumLibFuncs);
383 LibFunc::Func F = static_cast<LibFunc::Func>(I);
385 Libcalls.push_back(TLI.getName(F));
388 // TargetLowering has info on library calls that CodeGen expects to be
389 // available, both from the C runtime and compiler-rt.
391 for (unsigned I = 0, E = static_cast<unsigned>(RTLIB::UNKNOWN_LIBCALL);
394 = Lowering->getLibcallName(static_cast<RTLIB::Libcall>(I)))
395 Libcalls.push_back(Name);
397 array_pod_sort(Libcalls.begin(), Libcalls.end());
398 Libcalls.erase(std::unique(Libcalls.begin(), Libcalls.end()),
402 void LTOCodeGenerator::applyScopeRestrictions() {
403 if (ScopeRestrictionsDone || !shouldInternalize())
405 Module *mergedModule = Linker.getModule();
407 // Start off with a verification pass.
409 passes.add(createVerifierPass());
411 // mark which symbols can not be internalized
412 Mangler Mangler(TargetMach->getDataLayout());
413 std::vector<const char*> MustPreserveList;
414 SmallPtrSet<GlobalValue*, 8> AsmUsed;
415 std::vector<StringRef> Libcalls;
416 TargetLibraryInfo TLI(Triple(TargetMach->getTargetTriple()));
417 accumulateAndSortLibcalls(Libcalls, TLI, TargetMach->getTargetLowering());
419 for (Module::iterator f = mergedModule->begin(),
420 e = mergedModule->end(); f != e; ++f)
421 applyRestriction(*f, Libcalls, MustPreserveList, AsmUsed, Mangler);
422 for (Module::global_iterator v = mergedModule->global_begin(),
423 e = mergedModule->global_end(); v != e; ++v)
424 applyRestriction(*v, Libcalls, MustPreserveList, AsmUsed, Mangler);
425 for (Module::alias_iterator a = mergedModule->alias_begin(),
426 e = mergedModule->alias_end(); a != e; ++a)
427 applyRestriction(*a, Libcalls, MustPreserveList, AsmUsed, Mangler);
429 GlobalVariable *LLVMCompilerUsed =
430 mergedModule->getGlobalVariable("llvm.compiler.used");
431 findUsedValues(LLVMCompilerUsed, AsmUsed);
432 if (LLVMCompilerUsed)
433 LLVMCompilerUsed->eraseFromParent();
435 if (!AsmUsed.empty()) {
436 llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(Context);
437 std::vector<Constant*> asmUsed2;
438 for (SmallPtrSet<GlobalValue*, 16>::const_iterator i = AsmUsed.begin(),
439 e = AsmUsed.end(); i !=e; ++i) {
440 GlobalValue *GV = *i;
441 Constant *c = ConstantExpr::getBitCast(GV, i8PTy);
442 asmUsed2.push_back(c);
445 llvm::ArrayType *ATy = llvm::ArrayType::get(i8PTy, asmUsed2.size());
447 new llvm::GlobalVariable(*mergedModule, ATy, false,
448 llvm::GlobalValue::AppendingLinkage,
449 llvm::ConstantArray::get(ATy, asmUsed2),
450 "llvm.compiler.used");
452 LLVMCompilerUsed->setSection("llvm.metadata");
456 createInternalizePass(MustPreserveList, shouldOnlyInternalizeHidden()));
458 // apply scope restrictions
459 passes.run(*mergedModule);
461 ScopeRestrictionsDone = true;
464 /// Optimize merged modules using various IPO passes
465 bool LTOCodeGenerator::generateObjectFile(raw_ostream &out,
468 bool DisableGVNLoadPRE,
469 std::string &errMsg) {
470 if (!this->determineTarget(errMsg))
473 Module *mergedModule = Linker.getModule();
475 // Mark which symbols can not be internalized
476 this->applyScopeRestrictions();
478 // Instantiate the pass manager to organize the passes.
481 // Start off with a verification pass.
482 passes.add(createVerifierPass());
484 // Add an appropriate DataLayout instance for this module...
485 mergedModule->setDataLayout(TargetMach->getDataLayout());
486 passes.add(new DataLayoutPass(mergedModule));
488 // Add appropriate TargetLibraryInfo for this module.
489 passes.add(new TargetLibraryInfo(Triple(TargetMach->getTargetTriple())));
491 TargetMach->addAnalysisPasses(passes);
493 // Enabling internalize here would use its AllButMain variant. It
494 // keeps only main if it exists and does nothing for libraries. Instead
495 // we create the pass ourselves with the symbol list provided by the linker.
497 PassManagerBuilder().populateLTOPassManager(passes,
498 /*Internalize=*/false,
502 // Make sure everything is still good.
503 passes.add(createVerifierPass());
505 PassManager codeGenPasses;
507 codeGenPasses.add(new DataLayoutPass(mergedModule));
509 formatted_raw_ostream Out(out);
511 // If the bitcode files contain ARC code and were compiled with optimization,
512 // the ObjCARCContractPass must be run, so do it unconditionally here.
513 codeGenPasses.add(createObjCARCContractPass());
515 if (TargetMach->addPassesToEmitFile(codeGenPasses, Out,
516 TargetMachine::CGFT_ObjectFile)) {
517 errMsg = "target file type not supported";
521 // Run our queue of passes all at once now, efficiently.
522 passes.run(*mergedModule);
524 // Run the code generator, and write assembly file
525 codeGenPasses.run(*mergedModule);
530 /// setCodeGenDebugOptions - Set codegen debugging options to aid in debugging
532 void LTOCodeGenerator::setCodeGenDebugOptions(const char *options) {
533 for (std::pair<StringRef, StringRef> o = getToken(options);
534 !o.first.empty(); o = getToken(o.second)) {
535 // ParseCommandLineOptions() expects argv[0] to be program name. Lazily add
537 if (CodegenOptions.empty())
538 CodegenOptions.push_back(strdup("libLLVMLTO"));
539 CodegenOptions.push_back(strdup(o.first.str().c_str()));
543 void LTOCodeGenerator::parseCodeGenDebugOptions() {
544 // if options were requested, set them
545 if (!CodegenOptions.empty())
546 cl::ParseCommandLineOptions(CodegenOptions.size(),
547 const_cast<char **>(&CodegenOptions[0]));
550 void LTOCodeGenerator::DiagnosticHandler(const DiagnosticInfo &DI,
552 ((LTOCodeGenerator *)Context)->DiagnosticHandler2(DI);
555 void LTOCodeGenerator::DiagnosticHandler2(const DiagnosticInfo &DI) {
556 // Map the LLVM internal diagnostic severity to the LTO diagnostic severity.
557 lto_codegen_diagnostic_severity_t Severity;
558 switch (DI.getSeverity()) {
560 Severity = LTO_DS_ERROR;
563 Severity = LTO_DS_WARNING;
566 Severity = LTO_DS_REMARK;
569 Severity = LTO_DS_NOTE;
572 // Create the string that will be reported to the external diagnostic handler.
573 std::string MsgStorage;
574 raw_string_ostream Stream(MsgStorage);
575 DiagnosticPrinterRawOStream DP(Stream);
579 // If this method has been called it means someone has set up an external
580 // diagnostic handler. Assert on that.
581 assert(DiagHandler && "Invalid diagnostic handler");
582 (*DiagHandler)(Severity, MsgStorage.c_str(), DiagContext);
586 LTOCodeGenerator::setDiagnosticHandler(lto_diagnostic_handler_t DiagHandler,
588 this->DiagHandler = DiagHandler;
589 this->DiagContext = Ctxt;
591 return Context.setDiagnosticHandler(NULL, NULL);
592 // Register the LTOCodeGenerator stub in the LLVMContext to forward the
593 // diagnostic to the external DiagHandler.
594 Context.setDiagnosticHandler(LTOCodeGenerator::DiagnosticHandler, this);