1 //===--- BackendUtil.cpp - LLVM Backend Utilities -------------------------===//
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 #include "clang/CodeGen/BackendUtil.h"
11 #include "clang/Basic/Diagnostic.h"
12 #include "clang/Basic/LangOptions.h"
13 #include "clang/Basic/TargetOptions.h"
14 #include "clang/Frontend/CodeGenOptions.h"
15 #include "clang/Frontend/FrontendDiagnostic.h"
16 #include "llvm/Analysis/Verifier.h"
17 #include "llvm/Assembly/PrintModulePass.h"
18 #include "llvm/Bitcode/ReaderWriter.h"
19 #include "llvm/CodeGen/RegAllocRegistry.h"
20 #include "llvm/CodeGen/SchedulerRegistry.h"
21 #include "llvm/IR/DataLayout.h"
22 #include "llvm/IR/Module.h"
23 #include "llvm/MC/SubtargetFeature.h"
24 #include "llvm/PassManager.h"
25 #include "llvm/Support/CommandLine.h"
26 #include "llvm/Support/FormattedStream.h"
27 #include "llvm/Support/PrettyStackTrace.h"
28 #include "llvm/Support/TargetRegistry.h"
29 #include "llvm/Support/Timer.h"
30 #include "llvm/Support/raw_ostream.h"
31 #include "llvm/Target/TargetLibraryInfo.h"
32 #include "llvm/Target/TargetMachine.h"
33 #include "llvm/Target/TargetOptions.h"
34 #include "llvm/Transforms/IPO.h"
35 #include "llvm/Transforms/IPO/PassManagerBuilder.h"
36 #include "llvm/Transforms/Instrumentation.h"
37 #include "llvm/Transforms/ObjCARC.h"
38 #include "llvm/Transforms/Scalar.h"
39 using namespace clang;
44 class EmitAssemblyHelper {
45 DiagnosticsEngine &Diags;
46 const CodeGenOptions &CodeGenOpts;
47 const clang::TargetOptions &TargetOpts;
48 const LangOptions &LangOpts;
51 Timer CodeGenerationTime;
53 mutable PassManager *CodeGenPasses;
54 mutable PassManager *PerModulePasses;
55 mutable FunctionPassManager *PerFunctionPasses;
58 PassManager *getCodeGenPasses(TargetMachine *TM) const {
60 CodeGenPasses = new PassManager();
61 CodeGenPasses->add(new DataLayout(TheModule));
63 TM->addAnalysisPasses(*CodeGenPasses);
68 PassManager *getPerModulePasses(TargetMachine *TM) const {
69 if (!PerModulePasses) {
70 PerModulePasses = new PassManager();
71 PerModulePasses->add(new DataLayout(TheModule));
73 TM->addAnalysisPasses(*PerModulePasses);
75 return PerModulePasses;
78 FunctionPassManager *getPerFunctionPasses(TargetMachine *TM) const {
79 if (!PerFunctionPasses) {
80 PerFunctionPasses = new FunctionPassManager(TheModule);
81 PerFunctionPasses->add(new DataLayout(TheModule));
83 TM->addAnalysisPasses(*PerFunctionPasses);
85 return PerFunctionPasses;
89 void CreatePasses(TargetMachine *TM);
91 /// CreateTargetMachine - Generates the TargetMachine.
92 /// Returns Null if it is unable to create the target machine.
93 /// Some of our clang tests specify triples which are not built
94 /// into clang. This is okay because these tests check the generated
95 /// IR, and they require DataLayout which depends on the triple.
96 /// In this case, we allow this method to fail and not report an error.
97 /// When MustCreateTM is used, we print an error if we are unable to load
98 /// the requested target.
99 TargetMachine *CreateTargetMachine(bool MustCreateTM);
101 /// AddEmitPasses - Add passes necessary to emit assembly or LLVM IR.
103 /// \return True on success.
104 bool AddEmitPasses(BackendAction Action, formatted_raw_ostream &OS,
108 EmitAssemblyHelper(DiagnosticsEngine &_Diags,
109 const CodeGenOptions &CGOpts,
110 const clang::TargetOptions &TOpts,
111 const LangOptions &LOpts,
113 : Diags(_Diags), CodeGenOpts(CGOpts), TargetOpts(TOpts), LangOpts(LOpts),
114 TheModule(M), CodeGenerationTime("Code Generation Time"),
115 CodeGenPasses(0), PerModulePasses(0), PerFunctionPasses(0) {}
117 ~EmitAssemblyHelper() {
118 delete CodeGenPasses;
119 delete PerModulePasses;
120 delete PerFunctionPasses;
123 void EmitAssembly(BackendAction Action, raw_ostream *OS);
126 // We need this wrapper to access LangOpts and CGOpts from extension functions
127 // that we add to the PassManagerBuilder.
128 class PassManagerBuilderWrapper : public PassManagerBuilder {
130 PassManagerBuilderWrapper(const CodeGenOptions &CGOpts,
131 const LangOptions &LangOpts)
132 : PassManagerBuilder(), CGOpts(CGOpts), LangOpts(LangOpts) {}
133 const CodeGenOptions &getCGOpts() const { return CGOpts; }
134 const LangOptions &getLangOpts() const { return LangOpts; }
136 const CodeGenOptions &CGOpts;
137 const LangOptions &LangOpts;
142 static void addObjCARCAPElimPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
143 if (Builder.OptLevel > 0)
144 PM.add(createObjCARCAPElimPass());
147 static void addObjCARCExpandPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
148 if (Builder.OptLevel > 0)
149 PM.add(createObjCARCExpandPass());
152 static void addObjCARCOptPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
153 if (Builder.OptLevel > 0)
154 PM.add(createObjCARCOptPass());
157 static void addBoundsCheckingPass(const PassManagerBuilder &Builder,
158 PassManagerBase &PM) {
159 PM.add(createBoundsCheckingPass());
162 static void addAddressSanitizerPasses(const PassManagerBuilder &Builder,
163 PassManagerBase &PM) {
164 const PassManagerBuilderWrapper &BuilderWrapper =
165 static_cast<const PassManagerBuilderWrapper&>(Builder);
166 const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
167 const LangOptions &LangOpts = BuilderWrapper.getLangOpts();
168 PM.add(createAddressSanitizerFunctionPass(
169 LangOpts.Sanitize.InitOrder,
170 LangOpts.Sanitize.UseAfterReturn,
171 LangOpts.Sanitize.UseAfterScope,
172 CGOpts.SanitizerBlacklistFile,
173 CGOpts.SanitizeAddressZeroBaseShadow));
174 PM.add(createAddressSanitizerModulePass(
175 LangOpts.Sanitize.InitOrder,
176 CGOpts.SanitizerBlacklistFile,
177 CGOpts.SanitizeAddressZeroBaseShadow));
180 static void addMemorySanitizerPass(const PassManagerBuilder &Builder,
181 PassManagerBase &PM) {
182 const PassManagerBuilderWrapper &BuilderWrapper =
183 static_cast<const PassManagerBuilderWrapper&>(Builder);
184 const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
185 PM.add(createMemorySanitizerPass(CGOpts.SanitizeMemoryTrackOrigins,
186 CGOpts.SanitizerBlacklistFile));
188 // MemorySanitizer inserts complex instrumentation that mostly follows
189 // the logic of the original code, but operates on "shadow" values.
190 // It can benefit from re-running some general purpose optimization passes.
191 if (Builder.OptLevel > 0) {
192 PM.add(createEarlyCSEPass());
193 PM.add(createReassociatePass());
194 PM.add(createLICMPass());
195 PM.add(createGVNPass());
196 PM.add(createInstructionCombiningPass());
197 PM.add(createDeadStoreEliminationPass());
201 static void addThreadSanitizerPass(const PassManagerBuilder &Builder,
202 PassManagerBase &PM) {
203 const PassManagerBuilderWrapper &BuilderWrapper =
204 static_cast<const PassManagerBuilderWrapper&>(Builder);
205 const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
206 PM.add(createThreadSanitizerPass(CGOpts.SanitizerBlacklistFile));
209 void EmitAssemblyHelper::CreatePasses(TargetMachine *TM) {
210 unsigned OptLevel = CodeGenOpts.OptimizationLevel;
211 CodeGenOptions::InliningMethod Inlining = CodeGenOpts.getInlining();
213 // Handle disabling of LLVM optimization, where we want to preserve the
214 // internal module before any optimization.
215 if (CodeGenOpts.DisableLLVMOpts) {
217 Inlining = CodeGenOpts.NoInlining;
220 PassManagerBuilderWrapper PMBuilder(CodeGenOpts, LangOpts);
221 PMBuilder.OptLevel = OptLevel;
222 PMBuilder.SizeLevel = CodeGenOpts.OptimizeSize;
224 PMBuilder.DisableSimplifyLibCalls = !CodeGenOpts.SimplifyLibCalls;
225 PMBuilder.DisableUnitAtATime = !CodeGenOpts.UnitAtATime;
226 PMBuilder.DisableUnrollLoops = !CodeGenOpts.UnrollLoops;
228 // In ObjC ARC mode, add the main ARC optimization passes.
229 if (LangOpts.ObjCAutoRefCount) {
230 PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
231 addObjCARCExpandPass);
232 PMBuilder.addExtension(PassManagerBuilder::EP_ModuleOptimizerEarly,
233 addObjCARCAPElimPass);
234 PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
238 if (LangOpts.Sanitize.Bounds) {
239 PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
240 addBoundsCheckingPass);
241 PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
242 addBoundsCheckingPass);
245 if (LangOpts.Sanitize.Address) {
246 PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
247 addAddressSanitizerPasses);
248 PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
249 addAddressSanitizerPasses);
252 if (LangOpts.Sanitize.Memory) {
253 PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
254 addMemorySanitizerPass);
255 PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
256 addMemorySanitizerPass);
259 if (LangOpts.Sanitize.Thread) {
260 PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
261 addThreadSanitizerPass);
262 PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
263 addThreadSanitizerPass);
266 // Figure out TargetLibraryInfo.
267 Triple TargetTriple(TheModule->getTargetTriple());
268 PMBuilder.LibraryInfo = new TargetLibraryInfo(TargetTriple);
269 if (!CodeGenOpts.SimplifyLibCalls)
270 PMBuilder.LibraryInfo->disableAllFunctions();
273 case CodeGenOptions::NoInlining: break;
274 case CodeGenOptions::NormalInlining: {
275 // FIXME: Derive these constants in a principled fashion.
276 unsigned Threshold = 225;
277 if (CodeGenOpts.OptimizeSize == 1) // -Os
279 else if (CodeGenOpts.OptimizeSize == 2) // -Oz
281 else if (OptLevel > 2)
283 PMBuilder.Inliner = createFunctionInliningPass(Threshold);
286 case CodeGenOptions::OnlyAlwaysInlining:
287 // Respect always_inline.
289 // Do not insert lifetime intrinsics at -O0.
290 PMBuilder.Inliner = createAlwaysInlinerPass(false);
292 PMBuilder.Inliner = createAlwaysInlinerPass();
296 // Set up the per-function pass manager.
297 FunctionPassManager *FPM = getPerFunctionPasses(TM);
298 if (CodeGenOpts.VerifyModule)
299 FPM->add(createVerifierPass());
300 PMBuilder.populateFunctionPassManager(*FPM);
302 // Set up the per-module pass manager.
303 PassManager *MPM = getPerModulePasses(TM);
305 if (!CodeGenOpts.DisableGCov &&
306 (CodeGenOpts.EmitGcovArcs || CodeGenOpts.EmitGcovNotes)) {
307 // Not using 'GCOVOptions::getDefault' allows us to avoid exiting if
308 // LLVM's -default-gcov-version flag is set to something invalid.
310 Options.EmitNotes = CodeGenOpts.EmitGcovNotes;
311 Options.EmitData = CodeGenOpts.EmitGcovArcs;
312 memcpy(Options.Version, CodeGenOpts.CoverageVersion, 4);
313 Options.UseCfgChecksum = CodeGenOpts.CoverageExtraChecksum;
314 Options.NoRedZone = CodeGenOpts.DisableRedZone;
315 Options.FunctionNamesInData =
316 !CodeGenOpts.CoverageNoFunctionNamesInData;
317 MPM->add(createGCOVProfilerPass(Options));
318 if (CodeGenOpts.getDebugInfo() == CodeGenOptions::NoDebugInfo)
319 MPM->add(createStripSymbolsPass(true));
322 PMBuilder.populateModulePassManager(*MPM);
325 TargetMachine *EmitAssemblyHelper::CreateTargetMachine(bool MustCreateTM) {
326 // Create the TargetMachine for generating code.
328 std::string Triple = TheModule->getTargetTriple();
329 const llvm::Target *TheTarget = TargetRegistry::lookupTarget(Triple, Error);
332 Diags.Report(diag::err_fe_unable_to_create_target) << Error;
336 // FIXME: Expose these capabilities via actual APIs!!!! Aside from just
337 // being gross, this is also totally broken if we ever care about
340 TargetMachine::setAsmVerbosityDefault(CodeGenOpts.AsmVerbose);
342 TargetMachine::setFunctionSections(CodeGenOpts.FunctionSections);
343 TargetMachine::setDataSections (CodeGenOpts.DataSections);
345 // FIXME: Parse this earlier.
346 llvm::CodeModel::Model CM;
347 if (CodeGenOpts.CodeModel == "small") {
348 CM = llvm::CodeModel::Small;
349 } else if (CodeGenOpts.CodeModel == "kernel") {
350 CM = llvm::CodeModel::Kernel;
351 } else if (CodeGenOpts.CodeModel == "medium") {
352 CM = llvm::CodeModel::Medium;
353 } else if (CodeGenOpts.CodeModel == "large") {
354 CM = llvm::CodeModel::Large;
356 assert(CodeGenOpts.CodeModel.empty() && "Invalid code model!");
357 CM = llvm::CodeModel::Default;
360 SmallVector<const char *, 16> BackendArgs;
361 BackendArgs.push_back("clang"); // Fake program name.
362 if (!CodeGenOpts.DebugPass.empty()) {
363 BackendArgs.push_back("-debug-pass");
364 BackendArgs.push_back(CodeGenOpts.DebugPass.c_str());
366 if (!CodeGenOpts.LimitFloatPrecision.empty()) {
367 BackendArgs.push_back("-limit-float-precision");
368 BackendArgs.push_back(CodeGenOpts.LimitFloatPrecision.c_str());
370 if (llvm::TimePassesIsEnabled)
371 BackendArgs.push_back("-time-passes");
372 for (unsigned i = 0, e = CodeGenOpts.BackendOptions.size(); i != e; ++i)
373 BackendArgs.push_back(CodeGenOpts.BackendOptions[i].c_str());
374 if (CodeGenOpts.NoGlobalMerge)
375 BackendArgs.push_back("-global-merge=false");
376 BackendArgs.push_back(0);
377 llvm::cl::ParseCommandLineOptions(BackendArgs.size() - 1,
380 std::string FeaturesStr;
381 if (TargetOpts.Features.size()) {
382 SubtargetFeatures Features;
383 for (std::vector<std::string>::const_iterator
384 it = TargetOpts.Features.begin(),
385 ie = TargetOpts.Features.end(); it != ie; ++it)
386 Features.AddFeature(*it);
387 FeaturesStr = Features.getString();
390 llvm::Reloc::Model RM = llvm::Reloc::Default;
391 if (CodeGenOpts.RelocationModel == "static") {
392 RM = llvm::Reloc::Static;
393 } else if (CodeGenOpts.RelocationModel == "pic") {
394 RM = llvm::Reloc::PIC_;
396 assert(CodeGenOpts.RelocationModel == "dynamic-no-pic" &&
397 "Invalid PIC model!");
398 RM = llvm::Reloc::DynamicNoPIC;
401 CodeGenOpt::Level OptLevel = CodeGenOpt::Default;
402 switch (CodeGenOpts.OptimizationLevel) {
404 case 0: OptLevel = CodeGenOpt::None; break;
405 case 3: OptLevel = CodeGenOpt::Aggressive; break;
408 llvm::TargetOptions Options;
410 // Set frame pointer elimination mode.
411 if (!CodeGenOpts.DisableFPElim) {
412 Options.NoFramePointerElim = false;
413 Options.NoFramePointerElimNonLeaf = false;
414 } else if (CodeGenOpts.OmitLeafFramePointer) {
415 Options.NoFramePointerElim = false;
416 Options.NoFramePointerElimNonLeaf = true;
418 Options.NoFramePointerElim = true;
419 Options.NoFramePointerElimNonLeaf = true;
422 if (CodeGenOpts.UseInitArray)
423 Options.UseInitArray = true;
425 // Set float ABI type.
426 if (CodeGenOpts.FloatABI == "soft" || CodeGenOpts.FloatABI == "softfp")
427 Options.FloatABIType = llvm::FloatABI::Soft;
428 else if (CodeGenOpts.FloatABI == "hard")
429 Options.FloatABIType = llvm::FloatABI::Hard;
431 assert(CodeGenOpts.FloatABI.empty() && "Invalid float abi!");
432 Options.FloatABIType = llvm::FloatABI::Default;
435 // Set FP fusion mode.
436 switch (CodeGenOpts.getFPContractMode()) {
437 case CodeGenOptions::FPC_Off:
438 Options.AllowFPOpFusion = llvm::FPOpFusion::Strict;
440 case CodeGenOptions::FPC_On:
441 Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
443 case CodeGenOptions::FPC_Fast:
444 Options.AllowFPOpFusion = llvm::FPOpFusion::Fast;
448 Options.LessPreciseFPMADOption = CodeGenOpts.LessPreciseFPMAD;
449 Options.NoInfsFPMath = CodeGenOpts.NoInfsFPMath;
450 Options.NoNaNsFPMath = CodeGenOpts.NoNaNsFPMath;
451 Options.NoZerosInBSS = CodeGenOpts.NoZeroInitializedInBSS;
452 Options.UnsafeFPMath = CodeGenOpts.UnsafeFPMath;
453 Options.UseSoftFloat = CodeGenOpts.SoftFloat;
454 Options.StackAlignmentOverride = CodeGenOpts.StackAlignment;
455 Options.RealignStack = CodeGenOpts.StackRealignment;
456 Options.DisableTailCalls = CodeGenOpts.DisableTailCalls;
457 Options.TrapFuncName = CodeGenOpts.TrapFuncName;
458 Options.PositionIndependentExecutable = LangOpts.PIELevel != 0;
459 Options.SSPBufferSize = CodeGenOpts.SSPBufferSize;
460 Options.EnableSegmentedStacks = CodeGenOpts.EnableSegmentedStacks;
462 TargetMachine *TM = TheTarget->createTargetMachine(Triple, TargetOpts.CPU,
463 FeaturesStr, Options,
466 if (CodeGenOpts.RelaxAll)
467 TM->setMCRelaxAll(true);
468 if (CodeGenOpts.SaveTempLabels)
469 TM->setMCSaveTempLabels(true);
470 if (CodeGenOpts.NoDwarf2CFIAsm)
471 TM->setMCUseCFI(false);
472 if (!CodeGenOpts.NoDwarfDirectoryAsm)
473 TM->setMCUseDwarfDirectory(true);
474 if (CodeGenOpts.NoExecStack)
475 TM->setMCNoExecStack(true);
480 bool EmitAssemblyHelper::AddEmitPasses(BackendAction Action,
481 formatted_raw_ostream &OS,
484 // Create the code generator passes.
485 PassManager *PM = getCodeGenPasses(TM);
488 llvm::Triple TargetTriple(TheModule->getTargetTriple());
489 TargetLibraryInfo *TLI = new TargetLibraryInfo(TargetTriple);
490 if (!CodeGenOpts.SimplifyLibCalls)
491 TLI->disableAllFunctions();
494 // Add Target specific analysis passes.
495 TM->addAnalysisPasses(*PM);
497 // Normal mode, emit a .s or .o file by running the code generator. Note,
498 // this also adds codegenerator level optimization passes.
499 TargetMachine::CodeGenFileType CGFT = TargetMachine::CGFT_AssemblyFile;
500 if (Action == Backend_EmitObj)
501 CGFT = TargetMachine::CGFT_ObjectFile;
502 else if (Action == Backend_EmitMCNull)
503 CGFT = TargetMachine::CGFT_Null;
505 assert(Action == Backend_EmitAssembly && "Invalid action!");
507 // Add ObjC ARC final-cleanup optimizations. This is done as part of the
508 // "codegen" passes so that it isn't run multiple times when there is
509 // inlining happening.
510 if (LangOpts.ObjCAutoRefCount &&
511 CodeGenOpts.OptimizationLevel > 0)
512 PM->add(createObjCARCContractPass());
514 if (TM->addPassesToEmitFile(*PM, OS, CGFT,
515 /*DisableVerify=*/!CodeGenOpts.VerifyModule)) {
516 Diags.Report(diag::err_fe_unable_to_interface_with_target);
523 void EmitAssemblyHelper::EmitAssembly(BackendAction Action, raw_ostream *OS) {
524 TimeRegion Region(llvm::TimePassesIsEnabled ? &CodeGenerationTime : 0);
525 llvm::formatted_raw_ostream FormattedOS;
527 bool UsesCodeGen = (Action != Backend_EmitNothing &&
528 Action != Backend_EmitBC &&
529 Action != Backend_EmitLL);
530 TargetMachine *TM = CreateTargetMachine(UsesCodeGen);
531 if (UsesCodeGen && !TM) return;
535 case Backend_EmitNothing:
539 getPerModulePasses(TM)->add(createBitcodeWriterPass(*OS));
543 FormattedOS.setStream(*OS, formatted_raw_ostream::PRESERVE_STREAM);
544 getPerModulePasses(TM)->add(createPrintModulePass(&FormattedOS));
548 FormattedOS.setStream(*OS, formatted_raw_ostream::PRESERVE_STREAM);
549 if (!AddEmitPasses(Action, FormattedOS, TM))
553 // Before executing passes, print the final values of the LLVM options.
554 cl::PrintOptionValues();
556 // Run passes. For now we do all passes at once, but eventually we
557 // would like to have the option of streaming code generation.
559 if (PerFunctionPasses) {
560 PrettyStackTraceString CrashInfo("Per-function optimization");
562 PerFunctionPasses->doInitialization();
563 for (Module::iterator I = TheModule->begin(),
564 E = TheModule->end(); I != E; ++I)
565 if (!I->isDeclaration())
566 PerFunctionPasses->run(*I);
567 PerFunctionPasses->doFinalization();
570 if (PerModulePasses) {
571 PrettyStackTraceString CrashInfo("Per-module optimization passes");
572 PerModulePasses->run(*TheModule);
576 PrettyStackTraceString CrashInfo("Code generation");
577 CodeGenPasses->run(*TheModule);
581 void clang::EmitBackendOutput(DiagnosticsEngine &Diags,
582 const CodeGenOptions &CGOpts,
583 const clang::TargetOptions &TOpts,
584 const LangOptions &LOpts,
586 BackendAction Action, raw_ostream *OS) {
587 EmitAssemblyHelper AsmHelper(Diags, CGOpts, TOpts, LOpts, M);
589 AsmHelper.EmitAssembly(Action, OS);