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(createGlobalOptimizerPass());     // Optimize out global vars
 160
 161     MPM.add(createIPSCCPPass());              // IP SCCP
 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(createGVNPass());                 // Remove redundancies
 212   MPM.add(createMemCpyOptPass());             // Remove memcpy / form memset
 213   MPM.add(createSCCPPass());                  // Constant prop with SCCP
 214
 215   // Run instcombine after redundancy elimination to exploit opportunities
 216   // opened up by them.
 217   MPM.add(createInstructionCombiningPass());
 218   addExtensionsToPM(EP_Peephole, MPM);
 219   MPM.add(createJumpThreadingPass());         // Thread jumps
 220   MPM.add(createCorrelatedValuePropagationPass());
 221   MPM.add(createDeadStoreEliminationPass());  // Delete dead stores
 222
 223   addExtensionsToPM(EP_ScalarOptimizerLate, MPM);
 224
 225   if (RerollLoops)
 226     MPM.add(createLoopRerollPass());
 227   if (SLPVectorize)
 228     MPM.add(createSLPVectorizerPass());   // Vectorize parallel scalar chains.
 229
 230   if (BBVectorize) {
 231     MPM.add(createBBVectorizePass());
 232     MPM.add(createInstructionCombiningPass());
 233     addExtensionsToPM(EP_Peephole, MPM);
 234     if (OptLevel > 1 && UseGVNAfterVectorization)
 235       MPM.add(createGVNPass());           // Remove redundancies
 236     else
 237       MPM.add(createEarlyCSEPass());      // Catch trivial redundancies
 238
 239     // BBVectorize may have significantly shortened a loop body; unroll again.
 240     if (!DisableUnrollLoops)
 241       MPM.add(createLoopUnrollPass());
 242   }
 243
 244   if (LoadCombine)
 245     MPM.add(createLoadCombinePass());
 246
 247   MPM.add(createAggressiveDCEPass());         // Delete dead instructions
 248   MPM.add(createCFGSimplificationPass()); // Merge & remove BBs
 249   MPM.add(createInstructionCombiningPass());  // Clean up after everything.
 250   addExtensionsToPM(EP_Peephole, MPM);
 251
 252   // FIXME: This is a HACK! The inliner pass above implicitly creates a CGSCC
 253   // pass manager that we are specifically trying to avoid. To prevent this
 254   // we must insert a no-op module pass to reset the pass manager.
 255   MPM.add(createBarrierNoopPass());
 256   MPM.add(createLoopVectorizePass(DisableUnrollLoops, LoopVectorize));
 257   // FIXME: Because of #pragma vectorize enable, the passes below are always
 258   // inserted in the pipeline, even when the vectorizer doesn't run (ex. when
 259   // on -O1 and no #pragma is found). Would be good to have these two passes
 260   // as function calls, so that we can only pass them when the vectorizer
 261   // changed the code.
 262   MPM.add(createInstructionCombiningPass());
 263   addExtensionsToPM(EP_Peephole, MPM);
 264   MPM.add(createCFGSimplificationPass());
 265
 266   if (!DisableUnrollLoops)
 267     MPM.add(createLoopUnrollPass());    // Unroll small loops
 268
 269   if (!DisableUnitAtATime) {
 270     // FIXME: We shouldn't bother with this anymore.
 271     MPM.add(createStripDeadPrototypesPass()); // Get rid of dead prototypes
 272
 273     // GlobalOpt already deletes dead functions and globals, at -O2 try a
 274     // late pass of GlobalDCE.  It is capable of deleting dead cycles.
 275     if (OptLevel > 1) {
 276       MPM.add(createGlobalDCEPass());         // Remove dead fns and globals.
 277       MPM.add(createConstantMergePass());     // Merge dup global constants
 278     }
 279   }
 280   addExtensionsToPM(EP_OptimizerLast, MPM);
 281 }
 282
 283 void PassManagerBuilder::populateLTOPassManager(PassManagerBase &PM,
 284                                                 bool Internalize,
 285                                                 bool RunInliner,
 286                                                 bool DisableGVNLoadPRE) {
 287   // Provide AliasAnalysis services for optimizations.
 288   addInitialAliasAnalysisPasses(PM);
 289
 290   // Now that composite has been compiled, scan through the module, looking
 291   // for a main function.  If main is defined, mark all other functions
 292   // internal.
 293   if (Internalize)
 294     PM.add(createInternalizePass("main"));
 295
 296   // Propagate constants at call sites into the functions they call.  This
 297   // opens opportunities for globalopt (and inlining) by substituting function
 298   // pointers passed as arguments to direct uses of functions.
 299   PM.add(createIPSCCPPass());
 300
 301   // Now that we internalized some globals, see if we can hack on them!
 302   PM.add(createGlobalOptimizerPass());
 303
 304   // Linking modules together can lead to duplicated global constants, only
 305   // keep one copy of each constant.
 306   PM.add(createConstantMergePass());
 307
 308   // Remove unused arguments from functions.
 309   PM.add(createDeadArgEliminationPass());
 310
 311   // Reduce the code after globalopt and ipsccp.  Both can open up significant
 312   // simplification opportunities, and both can propagate functions through
 313   // function pointers.  When this happens, we often have to resolve varargs
 314   // calls, etc, so let instcombine do this.
 315   PM.add(createInstructionCombiningPass());
 316   addExtensionsToPM(EP_Peephole, PM);
 317
 318   // Inline small functions
 319   if (RunInliner)
 320     PM.add(createFunctionInliningPass());
 321
 322   PM.add(createPruneEHPass());   // Remove dead EH info.
 323
 324   // Optimize globals again if we ran the inliner.
 325   if (RunInliner)
 326     PM.add(createGlobalOptimizerPass());
 327   PM.add(createGlobalDCEPass()); // Remove dead functions.
 328
 329   // If we didn't decide to inline a function, check to see if we can
 330   // transform it to pass arguments by value instead of by reference.
 331   PM.add(createArgumentPromotionPass());
 332
 333   // The IPO passes may leave cruft around.  Clean up after them.
 334   PM.add(createInstructionCombiningPass());
 335   addExtensionsToPM(EP_Peephole, PM);
 336   PM.add(createJumpThreadingPass());
 337
 338   // Break up allocas
 339   if (UseNewSROA)
 340     PM.add(createSROAPass());
 341   else
 342     PM.add(createScalarReplAggregatesPass());
 343
 344   // Run a few AA driven optimizations here and now, to cleanup the code.
 345   PM.add(createFunctionAttrsPass()); // Add nocapture.
 346   PM.add(createGlobalsModRefPass()); // IP alias analysis.
 347
 348   PM.add(createLICMPass());                 // Hoist loop invariants.
 349   PM.add(createGVNPass(DisableGVNLoadPRE)); // Remove redundancies.
 350   PM.add(createMemCpyOptPass());            // Remove dead memcpys.
 351
 352   // Nuke dead stores.
 353   PM.add(createDeadStoreEliminationPass());
 354
 355   // More loops are countable; try to optimize them.
 356   PM.add(createIndVarSimplifyPass());
 357   PM.add(createLoopDeletionPass());
 358   PM.add(createLoopVectorizePass(true, true));
 359
 360   // More scalar chains could be vectorized due to more alias information
 361   PM.add(createSLPVectorizerPass()); // Vectorize parallel scalar chains.
 362
 363   if (LoadCombine)
 364     PM.add(createLoadCombinePass());
 365
 366   // Cleanup and simplify the code after the scalar optimizations.
 367   PM.add(createInstructionCombiningPass());
 368   addExtensionsToPM(EP_Peephole, PM);
 369
 370   PM.add(createJumpThreadingPass());
 371
 372   // Delete basic blocks, which optimization passes may have killed.
 373   PM.add(createCFGSimplificationPass());
 374
 375   // Now that we have optimized the program, discard unreachable functions.
 376   PM.add(createGlobalDCEPass());
 377 }
 378
 379 inline PassManagerBuilder *unwrap(LLVMPassManagerBuilderRef P) {
 380     return reinterpret_cast<PassManagerBuilder*>(P);
 381 }
 382
 383 inline LLVMPassManagerBuilderRef wrap(PassManagerBuilder *P) {
 384   return reinterpret_cast<LLVMPassManagerBuilderRef>(P);
 385 }
 386
 387 LLVMPassManagerBuilderRef LLVMPassManagerBuilderCreate() {
 388   PassManagerBuilder *PMB = new PassManagerBuilder();
 389   return wrap(PMB);
 390 }
 391
 392 void LLVMPassManagerBuilderDispose(LLVMPassManagerBuilderRef PMB) {
 393   PassManagerBuilder *Builder = unwrap(PMB);
 394   delete Builder;
 395 }
 396
 397 void
 398 LLVMPassManagerBuilderSetOptLevel(LLVMPassManagerBuilderRef PMB,
 399                                   unsigned OptLevel) {
 400   PassManagerBuilder *Builder = unwrap(PMB);
 401   Builder->OptLevel = OptLevel;
 402 }
 403
 404 void
 405 LLVMPassManagerBuilderSetSizeLevel(LLVMPassManagerBuilderRef PMB,
 406                                    unsigned SizeLevel) {
 407   PassManagerBuilder *Builder = unwrap(PMB);
 408   Builder->SizeLevel = SizeLevel;
 409 }
 410
 411 void
 412 LLVMPassManagerBuilderSetDisableUnitAtATime(LLVMPassManagerBuilderRef PMB,
 413                                             LLVMBool Value) {
 414   PassManagerBuilder *Builder = unwrap(PMB);
 415   Builder->DisableUnitAtATime = Value;
 416 }
 417
 418 void
 419 LLVMPassManagerBuilderSetDisableUnrollLoops(LLVMPassManagerBuilderRef PMB,
 420                                             LLVMBool Value) {
 421   PassManagerBuilder *Builder = unwrap(PMB);
 422   Builder->DisableUnrollLoops = Value;
 423 }
 424
 425 void
 426 LLVMPassManagerBuilderSetDisableSimplifyLibCalls(LLVMPassManagerBuilderRef PMB,
 427                                                  LLVMBool Value) {
 428   // NOTE: The simplify-libcalls pass has been removed.
 429 }
 430
 431 void
 432 LLVMPassManagerBuilderUseInlinerWithThreshold(LLVMPassManagerBuilderRef PMB,
 433                                               unsigned Threshold) {
 434   PassManagerBuilder *Builder = unwrap(PMB);
 435   Builder->Inliner = createFunctionInliningPass(Threshold);
 436 }
 437
 438 void
 439 LLVMPassManagerBuilderPopulateFunctionPassManager(LLVMPassManagerBuilderRef PMB,
 440                                                   LLVMPassManagerRef PM) {
 441   PassManagerBuilder *Builder = unwrap(PMB);
 442   FunctionPassManager *FPM = unwrap<FunctionPassManager>(PM);
 443   Builder->populateFunctionPassManager(*FPM);
 444 }
 445
 446 void
 447 LLVMPassManagerBuilderPopulateModulePassManager(LLVMPassManagerBuilderRef PMB,
 448                                                 LLVMPassManagerRef PM) {
 449   PassManagerBuilder *Builder = unwrap(PMB);
 450   PassManagerBase *MPM = unwrap(PM);
 451   Builder->populateModulePassManager(*MPM);
 452 }
 453
 454 void LLVMPassManagerBuilderPopulateLTOPassManager(LLVMPassManagerBuilderRef PMB,
 455                                                   LLVMPassManagerRef PM,
 456                                                   LLVMBool Internalize,
 457                                                   LLVMBool RunInliner) {
 458   PassManagerBuilder *Builder = unwrap(PMB);
 459   PassManagerBase *LPM = unwrap(PM);
 460   Builder->populateLTOPassManager(*LPM, Internalize != 0, RunInliner != 0);
 461 }