lib/Transforms/IPO/PassManagerBuilder.cpp

   1 //===- PassManagerBuilder.cpp - Build Standard Pass -----------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file defines the PassManagerBuilder class, which is used to set up a
  11 // "standard" optimization sequence suitable for languages like C and C++.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15
  16 #include "llvm/Transforms/IPO/PassManagerBuilder.h"
  17 #include "llvm-c/Transforms/PassManagerBuilder.h"
  18 #include "llvm/ADT/SmallVector.h"
  19 #include "llvm/Analysis/Passes.h"
  20 #include "llvm/IR/Verifier.h"
  21 #include "llvm/PassManager.h"
  22 #include "llvm/Support/CommandLine.h"
  23 #include "llvm/Support/ManagedStatic.h"
  24 #include "llvm/Target/TargetLibraryInfo.h"
  25 #include "llvm/Transforms/IPO.h"
  26 #include "llvm/Transforms/Scalar.h"
  27 #include "llvm/Transforms/Vectorize.h"
  28
  29 using namespace llvm;
  30
  31 static cl::opt<bool>
  32 RunLoopVectorization("vectorize-loops", cl::Hidden,
  33                      cl::desc("Run the Loop vectorization passes"));
  34
  35 static cl::opt<bool>
  36 RunSLPVectorization("vectorize-slp", cl::Hidden,
  37                     cl::desc("Run the SLP vectorization passes"));
  38
  39 static cl::opt<bool>
  40 RunBBVectorization("vectorize-slp-aggressive", cl::Hidden,
  41                     cl::desc("Run the BB vectorization passes"));
  42
  43 static cl::opt<bool>
  44 UseGVNAfterVectorization("use-gvn-after-vectorization",
  45   cl::init(false), cl::Hidden,
  46   cl::desc("Run GVN instead of Early CSE after vectorization passes"));
  47
  48 static cl::opt<bool> UseNewSROA("use-new-sroa",
  49   cl::init(true), cl::Hidden,
  50   cl::desc("Enable the new, experimental SROA pass"));
  51
  52 static cl::opt<bool>
  53 RunLoopRerolling("reroll-loops", cl::Hidden,
  54                  cl::desc("Run the loop rerolling pass"));
  55
  56 static cl::opt<bool> RunLoadCombine("combine-loads", cl::init(false),
  57                                     cl::Hidden,
  58                                     cl::desc("Run the load combining pass"));
  59
  60 PassManagerBuilder::PassManagerBuilder() {
  61     OptLevel = 2;
  62     SizeLevel = 0;
  63     LibraryInfo = nullptr;
  64     Inliner = nullptr;
  65     DisableTailCalls = false;
  66     DisableUnitAtATime = false;
  67     DisableUnrollLoops = false;
  68     BBVectorize = RunBBVectorization;
  69     SLPVectorize = RunSLPVectorization;
  70     LoopVectorize = RunLoopVectorization;
  71     RerollLoops = RunLoopRerolling;
  72     LoadCombine = RunLoadCombine;
  73 }
  74
  75 PassManagerBuilder::~PassManagerBuilder() {
  76   delete LibraryInfo;
  77   delete Inliner;
  78 }
  79
  80 /// Set of global extensions, automatically added as part of the standard set.
  81 static ManagedStatic<SmallVector<std::pair<PassManagerBuilder::ExtensionPointTy,
  82    PassManagerBuilder::ExtensionFn>, 8> > GlobalExtensions;
  83
  84 void PassManagerBuilder::addGlobalExtension(
  85     PassManagerBuilder::ExtensionPointTy Ty,
  86     PassManagerBuilder::ExtensionFn Fn) {
  87   GlobalExtensions->push_back(std::make_pair(Ty, Fn));
  88 }
  89
  90 void PassManagerBuilder::addExtension(ExtensionPointTy Ty, ExtensionFn Fn) {
  91   Extensions.push_back(std::make_pair(Ty, Fn));
  92 }
  93
  94 void PassManagerBuilder::addExtensionsToPM(ExtensionPointTy ETy,
  95                                            PassManagerBase &PM) const {
  96   for (unsigned i = 0, e = GlobalExtensions->size(); i != e; ++i)
  97     if ((*GlobalExtensions)[i].first == ETy)
  98       (*GlobalExtensions)[i].second(*this, PM);
  99   for (unsigned i = 0, e = Extensions.size(); i != e; ++i)
 100     if (Extensions[i].first == ETy)
 101       Extensions[i].second(*this, PM);
 102 }
 103
 104 void
 105 PassManagerBuilder::addInitialAliasAnalysisPasses(PassManagerBase &PM) const {
 106   // Add TypeBasedAliasAnalysis before BasicAliasAnalysis so that
 107   // BasicAliasAnalysis wins if they disagree. This is intended to help
 108   // support "obvious" type-punning idioms.
 109   PM.add(createTypeBasedAliasAnalysisPass());
 110   PM.add(createBasicAliasAnalysisPass());
 111 }
 112
 113 void PassManagerBuilder::populateFunctionPassManager(FunctionPassManager &FPM) {
 114   addExtensionsToPM(EP_EarlyAsPossible, FPM);
 115
 116   // Add LibraryInfo if we have some.
 117   if (LibraryInfo) FPM.add(new TargetLibraryInfo(*LibraryInfo));
 118
 119   if (OptLevel == 0) return;
 120
 121   addInitialAliasAnalysisPasses(FPM);
 122
 123   FPM.add(createCFGSimplificationPass());
 124   if (UseNewSROA)
 125     FPM.add(createSROAPass());
 126   else
 127     FPM.add(createScalarReplAggregatesPass());
 128   FPM.add(createEarlyCSEPass());
 129   FPM.add(createLowerExpectIntrinsicPass());
 130 }
 131
 132 void PassManagerBuilder::populateModulePassManager(PassManagerBase &MPM) {
 133   // If all optimizations are disabled, just run the always-inline pass.
 134   if (OptLevel == 0) {
 135     if (Inliner) {
 136       MPM.add(Inliner);
 137       Inliner = nullptr;
 138     }
 139
 140     // FIXME: This is a HACK! The inliner pass above implicitly creates a CGSCC
 141     // pass manager, but we don't want to add extensions into that pass manager.
 142     // To prevent this we must insert a no-op module pass to reset the pass
 143     // manager to get the same behavior as EP_OptimizerLast in non-O0 builds.
 144     if (!GlobalExtensions->empty() || !Extensions.empty())
 145       MPM.add(createBarrierNoopPass());
 146
 147     addExtensionsToPM(EP_EnabledOnOptLevel0, MPM);
 148     return;
 149   }
 150
 151   // Add LibraryInfo if we have some.
 152   if (LibraryInfo) MPM.add(new TargetLibraryInfo(*LibraryInfo));
 153
 154   addInitialAliasAnalysisPasses(MPM);
 155
 156   if (!DisableUnitAtATime) {
 157     addExtensionsToPM(EP_ModuleOptimizerEarly, MPM);
 158
 159     MPM.add(createIPSCCPPass());              // IP SCCP
 160     MPM.add(createGlobalOptimizerPass());     // Optimize out global vars
 161
 162     MPM.add(createDeadArgEliminationPass());  // Dead argument elimination
 163
 164     MPM.add(createInstructionCombiningPass());// Clean up after IPCP & DAE
 165     addExtensionsToPM(EP_Peephole, MPM);
 166     MPM.add(createCFGSimplificationPass());   // Clean up after IPCP & DAE
 167   }
 168
 169   // Start of CallGraph SCC passes.
 170   if (!DisableUnitAtATime)
 171     MPM.add(createPruneEHPass());             // Remove dead EH info
 172   if (Inliner) {
 173     MPM.add(Inliner);
 174     Inliner = nullptr;
 175   }
 176   if (!DisableUnitAtATime)
 177     MPM.add(createFunctionAttrsPass());       // Set readonly/readnone attrs
 178   if (OptLevel > 2)
 179     MPM.add(createArgumentPromotionPass());   // Scalarize uninlined fn args
 180
 181   // Start of function pass.
 182   // Break up aggregate allocas, using SSAUpdater.
 183   if (UseNewSROA)
 184     MPM.add(createSROAPass(/*RequiresDomTree*/ false));
 185   else
 186     MPM.add(createScalarReplAggregatesPass(-1, false));
 187   MPM.add(createEarlyCSEPass());              // Catch trivial redundancies
 188   MPM.add(createJumpThreadingPass());         // Thread jumps.
 189   MPM.add(createCorrelatedValuePropagationPass()); // Propagate conditionals
 190   MPM.add(createCFGSimplificationPass());     // Merge & remove BBs
 191   MPM.add(createInstructionCombiningPass());  // Combine silly seq's
 192   addExtensionsToPM(EP_Peephole, MPM);
 193
 194   if (!DisableTailCalls)
 195     MPM.add(createTailCallEliminationPass()); // Eliminate tail calls
 196   MPM.add(createCFGSimplificationPass());     // Merge & remove BBs
 197   MPM.add(createReassociatePass());           // Reassociate expressions
 198   MPM.add(createLoopRotatePass());            // Rotate Loop
 199   MPM.add(createLICMPass());                  // Hoist loop invariants
 200   MPM.add(createLoopUnswitchPass(SizeLevel || OptLevel < 3));
 201   MPM.add(createInstructionCombiningPass());
 202   MPM.add(createIndVarSimplifyPass());        // Canonicalize indvars
 203   MPM.add(createLoopIdiomPass());             // Recognize idioms like memset.
 204   MPM.add(createLoopDeletionPass());          // Delete dead loops
 205
 206   if (!DisableUnrollLoops)
 207     MPM.add(createSimpleLoopUnrollPass());    // Unroll small loops
 208   addExtensionsToPM(EP_LoopOptimizerEnd, MPM);
 209
 210   if (OptLevel > 1) {
 211     MPM.add(createMergedLoadStoreMotionPass()); // Merge load/stores in diamond
 212     MPM.add(createGVNPass());                 // Remove redundancies
 213   }
 214   MPM.add(createMemCpyOptPass());             // Remove memcpy / form memset
 215   MPM.add(createSCCPPass());                  // Constant prop with SCCP
 216
 217   // Run instcombine after redundancy elimination to exploit opportunities
 218   // opened up by them.
 219   MPM.add(createInstructionCombiningPass());
 220   addExtensionsToPM(EP_Peephole, MPM);
 221   MPM.add(createJumpThreadingPass());         // Thread jumps
 222   MPM.add(createCorrelatedValuePropagationPass());
 223   MPM.add(createDeadStoreEliminationPass());  // Delete dead stores
 224
 225   addExtensionsToPM(EP_ScalarOptimizerLate, MPM);
 226
 227   if (RerollLoops)
 228     MPM.add(createLoopRerollPass());
 229   if (SLPVectorize)
 230     MPM.add(createSLPVectorizerPass());   // Vectorize parallel scalar chains.
 231
 232   if (BBVectorize) {
 233     MPM.add(createBBVectorizePass());
 234     MPM.add(createInstructionCombiningPass());
 235     addExtensionsToPM(EP_Peephole, MPM);
 236     if (OptLevel > 1 && UseGVNAfterVectorization)
 237       MPM.add(createGVNPass());           // Remove redundancies
 238     else
 239       MPM.add(createEarlyCSEPass());      // Catch trivial redundancies
 240
 241     // BBVectorize may have significantly shortened a loop body; unroll again.
 242     if (!DisableUnrollLoops)
 243       MPM.add(createLoopUnrollPass());
 244   }
 245
 246   if (LoadCombine)
 247     MPM.add(createLoadCombinePass());
 248
 249   MPM.add(createAggressiveDCEPass());         // Delete dead instructions
 250   MPM.add(createCFGSimplificationPass()); // Merge & remove BBs
 251   MPM.add(createInstructionCombiningPass());  // Clean up after everything.
 252   addExtensionsToPM(EP_Peephole, MPM);
 253
 254   // FIXME: This is a HACK! The inliner pass above implicitly creates a CGSCC
 255   // pass manager that we are specifically trying to avoid. To prevent this
 256   // we must insert a no-op module pass to reset the pass manager.
 257   MPM.add(createBarrierNoopPass());
 258   MPM.add(createLoopVectorizePass(DisableUnrollLoops, LoopVectorize));
 259   // FIXME: Because of #pragma vectorize enable, the passes below are always
 260   // inserted in the pipeline, even when the vectorizer doesn't run (ex. when
 261   // on -O1 and no #pragma is found). Would be good to have these two passes
 262   // as function calls, so that we can only pass them when the vectorizer
 263   // changed the code.
 264   MPM.add(createInstructionCombiningPass());
 265   addExtensionsToPM(EP_Peephole, MPM);
 266   MPM.add(createCFGSimplificationPass());
 267
 268   if (!DisableUnrollLoops)
 269     MPM.add(createLoopUnrollPass());    // Unroll small loops
 270
 271   if (!DisableUnitAtATime) {
 272     // FIXME: We shouldn't bother with this anymore.
 273     MPM.add(createStripDeadPrototypesPass()); // Get rid of dead prototypes
 274
 275     // GlobalOpt already deletes dead functions and globals, at -O2 try a
 276     // late pass of GlobalDCE.  It is capable of deleting dead cycles.
 277     if (OptLevel > 1) {
 278       MPM.add(createGlobalDCEPass());         // Remove dead fns and globals.
 279       MPM.add(createConstantMergePass());     // Merge dup global constants
 280     }
 281   }
 282   addExtensionsToPM(EP_OptimizerLast, MPM);
 283 }
 284
 285 void PassManagerBuilder::populateLTOPassManager(PassManagerBase &PM,
 286                                                 bool Internalize,
 287                                                 bool RunInliner,
 288                                                 bool DisableGVNLoadPRE) {
 289   // Provide AliasAnalysis services for optimizations.
 290   addInitialAliasAnalysisPasses(PM);
 291
 292   // Now that composite has been compiled, scan through the module, looking
 293   // for a main function.  If main is defined, mark all other functions
 294   // internal.
 295   if (Internalize)
 296     PM.add(createInternalizePass("main"));
 297
 298   // Propagate constants at call sites into the functions they call.  This
 299   // opens opportunities for globalopt (and inlining) by substituting function
 300   // pointers passed as arguments to direct uses of functions.
 301   PM.add(createIPSCCPPass());
 302
 303   // Now that we internalized some globals, see if we can hack on them!
 304   PM.add(createGlobalOptimizerPass());
 305
 306   // Linking modules together can lead to duplicated global constants, only
 307   // keep one copy of each constant.
 308   PM.add(createConstantMergePass());
 309
 310   // Remove unused arguments from functions.
 311   PM.add(createDeadArgEliminationPass());
 312
 313   // Reduce the code after globalopt and ipsccp.  Both can open up significant
 314   // simplification opportunities, and both can propagate functions through
 315   // function pointers.  When this happens, we often have to resolve varargs
 316   // calls, etc, so let instcombine do this.
 317   PM.add(createInstructionCombiningPass());
 318   addExtensionsToPM(EP_Peephole, PM);
 319
 320   // Inline small functions
 321   if (RunInliner)
 322     PM.add(createFunctionInliningPass());
 323
 324   PM.add(createPruneEHPass());   // Remove dead EH info.
 325
 326   // Optimize globals again if we ran the inliner.
 327   if (RunInliner)
 328     PM.add(createGlobalOptimizerPass());
 329   PM.add(createGlobalDCEPass()); // Remove dead functions.
 330
 331   // If we didn't decide to inline a function, check to see if we can
 332   // transform it to pass arguments by value instead of by reference.
 333   PM.add(createArgumentPromotionPass());
 334
 335   // The IPO passes may leave cruft around.  Clean up after them.
 336   PM.add(createInstructionCombiningPass());
 337   addExtensionsToPM(EP_Peephole, PM);
 338   PM.add(createJumpThreadingPass());
 339
 340   // Break up allocas
 341   if (UseNewSROA)
 342     PM.add(createSROAPass());
 343   else
 344     PM.add(createScalarReplAggregatesPass());
 345
 346   // Run a few AA driven optimizations here and now, to cleanup the code.
 347   PM.add(createFunctionAttrsPass()); // Add nocapture.
 348   PM.add(createGlobalsModRefPass()); // IP alias analysis.
 349
 350   PM.add(createLICMPass());                 // Hoist loop invariants.
 351   PM.add(createMergedLoadStoreMotionPass()); // Merge load/stores in diamonds
 352   PM.add(createGVNPass(DisableGVNLoadPRE)); // Remove redundancies.
 353   PM.add(createMemCpyOptPass());            // Remove dead memcpys.
 354
 355   // Nuke dead stores.
 356   PM.add(createDeadStoreEliminationPass());
 357
 358   // More loops are countable; try to optimize them.
 359   PM.add(createIndVarSimplifyPass());
 360   PM.add(createLoopDeletionPass());
 361   PM.add(createLoopVectorizePass(true, true));
 362
 363   // More scalar chains could be vectorized due to more alias information
 364   PM.add(createSLPVectorizerPass()); // Vectorize parallel scalar chains.
 365
 366   if (LoadCombine)
 367     PM.add(createLoadCombinePass());
 368
 369   // Cleanup and simplify the code after the scalar optimizations.
 370   PM.add(createInstructionCombiningPass());
 371   addExtensionsToPM(EP_Peephole, PM);
 372
 373   PM.add(createJumpThreadingPass());
 374
 375   // Delete basic blocks, which optimization passes may have killed.
 376   PM.add(createCFGSimplificationPass());
 377
 378   // Now that we have optimized the program, discard unreachable functions.
 379   PM.add(createGlobalDCEPass());
 380 }
 381
 382 inline PassManagerBuilder *unwrap(LLVMPassManagerBuilderRef P) {
 383     return reinterpret_cast<PassManagerBuilder*>(P);
 384 }
 385
 386 inline LLVMPassManagerBuilderRef wrap(PassManagerBuilder *P) {
 387   return reinterpret_cast<LLVMPassManagerBuilderRef>(P);
 388 }
 389
 390 LLVMPassManagerBuilderRef LLVMPassManagerBuilderCreate() {
 391   PassManagerBuilder *PMB = new PassManagerBuilder();
 392   return wrap(PMB);
 393 }
 394
 395 void LLVMPassManagerBuilderDispose(LLVMPassManagerBuilderRef PMB) {
 396   PassManagerBuilder *Builder = unwrap(PMB);
 397   delete Builder;
 398 }
 399
 400 void
 401 LLVMPassManagerBuilderSetOptLevel(LLVMPassManagerBuilderRef PMB,
 402                                   unsigned OptLevel) {
 403   PassManagerBuilder *Builder = unwrap(PMB);
 404   Builder->OptLevel = OptLevel;
 405 }
 406
 407 void
 408 LLVMPassManagerBuilderSetSizeLevel(LLVMPassManagerBuilderRef PMB,
 409                                    unsigned SizeLevel) {
 410   PassManagerBuilder *Builder = unwrap(PMB);
 411   Builder->SizeLevel = SizeLevel;
 412 }
 413
 414 void
 415 LLVMPassManagerBuilderSetDisableUnitAtATime(LLVMPassManagerBuilderRef PMB,
 416                                             LLVMBool Value) {
 417   PassManagerBuilder *Builder = unwrap(PMB);
 418   Builder->DisableUnitAtATime = Value;
 419 }
 420
 421 void
 422 LLVMPassManagerBuilderSetDisableUnrollLoops(LLVMPassManagerBuilderRef PMB,
 423                                             LLVMBool Value) {
 424   PassManagerBuilder *Builder = unwrap(PMB);
 425   Builder->DisableUnrollLoops = Value;
 426 }
 427
 428 void
 429 LLVMPassManagerBuilderSetDisableSimplifyLibCalls(LLVMPassManagerBuilderRef PMB,
 430                                                  LLVMBool Value) {
 431   // NOTE: The simplify-libcalls pass has been removed.
 432 }
 433
 434 void
 435 LLVMPassManagerBuilderUseInlinerWithThreshold(LLVMPassManagerBuilderRef PMB,
 436                                               unsigned Threshold) {
 437   PassManagerBuilder *Builder = unwrap(PMB);
 438   Builder->Inliner = createFunctionInliningPass(Threshold);
 439 }
 440
 441 void
 442 LLVMPassManagerBuilderPopulateFunctionPassManager(LLVMPassManagerBuilderRef PMB,
 443                                                   LLVMPassManagerRef PM) {
 444   PassManagerBuilder *Builder = unwrap(PMB);
 445   FunctionPassManager *FPM = unwrap<FunctionPassManager>(PM);
 446   Builder->populateFunctionPassManager(*FPM);
 447 }
 448
 449 void
 450 LLVMPassManagerBuilderPopulateModulePassManager(LLVMPassManagerBuilderRef PMB,
 451                                                 LLVMPassManagerRef PM) {
 452   PassManagerBuilder *Builder = unwrap(PMB);
 453   PassManagerBase *MPM = unwrap(PM);
 454   Builder->populateModulePassManager(*MPM);
 455 }
 456
 457 void LLVMPassManagerBuilderPopulateLTOPassManager(LLVMPassManagerBuilderRef PMB,
 458                                                   LLVMPassManagerRef PM,
 459                                                   LLVMBool Internalize,
 460                                                   LLVMBool RunInliner) {
 461   PassManagerBuilder *Builder = unwrap(PMB);
 462   PassManagerBase *LPM = unwrap(PM);
 463   Builder->populateLTOPassManager(*LPM, Internalize != 0, RunInliner != 0);
 464 }