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(createScopedNoAliasAAPass());
 111   PM.add(createBasicAliasAnalysisPass());
 112 }
 113
 114 void PassManagerBuilder::populateFunctionPassManager(FunctionPassManager &FPM) {
 115   addExtensionsToPM(EP_EarlyAsPossible, FPM);
 116
 117   // Add LibraryInfo if we have some.
 118   if (LibraryInfo) FPM.add(new TargetLibraryInfo(*LibraryInfo));
 119
 120   if (OptLevel == 0) return;
 121
 122   addInitialAliasAnalysisPasses(FPM);
 123
 124   FPM.add(createCFGSimplificationPass());
 125   if (UseNewSROA)
 126     FPM.add(createSROAPass());
 127   else
 128     FPM.add(createScalarReplAggregatesPass());
 129   FPM.add(createEarlyCSEPass());
 130   FPM.add(createLowerExpectIntrinsicPass());
 131 }
 132
 133 void PassManagerBuilder::populateModulePassManager(PassManagerBase &MPM) {
 134   // If all optimizations are disabled, just run the always-inline pass.
 135   if (OptLevel == 0) {
 136     if (Inliner) {
 137       MPM.add(Inliner);
 138       Inliner = nullptr;
 139     }
 140
 141     // FIXME: This is a HACK! The inliner pass above implicitly creates a CGSCC
 142     // pass manager, but we don't want to add extensions into that pass manager.
 143     // To prevent this we must insert a no-op module pass to reset the pass
 144     // manager to get the same behavior as EP_OptimizerLast in non-O0 builds.
 145     if (!GlobalExtensions->empty() || !Extensions.empty())
 146       MPM.add(createBarrierNoopPass());
 147
 148     addExtensionsToPM(EP_EnabledOnOptLevel0, MPM);
 149     return;
 150   }
 151
 152   // Add LibraryInfo if we have some.
 153   if (LibraryInfo) MPM.add(new TargetLibraryInfo(*LibraryInfo));
 154
 155   addInitialAliasAnalysisPasses(MPM);
 156
 157   if (!DisableUnitAtATime) {
 158     addExtensionsToPM(EP_ModuleOptimizerEarly, MPM);
 159
 160     MPM.add(createIPSCCPPass());              // IP SCCP
 161     MPM.add(createGlobalOptimizerPass());     // Optimize out global vars
 162
 163     MPM.add(createDeadArgEliminationPass());  // Dead argument elimination
 164
 165     MPM.add(createInstructionCombiningPass());// Clean up after IPCP & DAE
 166     addExtensionsToPM(EP_Peephole, MPM);
 167     MPM.add(createCFGSimplificationPass());   // Clean up after IPCP & DAE
 168   }
 169
 170   // Start of CallGraph SCC passes.
 171   if (!DisableUnitAtATime)
 172     MPM.add(createPruneEHPass());             // Remove dead EH info
 173   if (Inliner) {
 174     MPM.add(Inliner);
 175     Inliner = nullptr;
 176   }
 177   if (!DisableUnitAtATime)
 178     MPM.add(createFunctionAttrsPass());       // Set readonly/readnone attrs
 179   if (OptLevel > 2)
 180     MPM.add(createArgumentPromotionPass());   // Scalarize uninlined fn args
 181
 182   // Start of function pass.
 183   // Break up aggregate allocas, using SSAUpdater.
 184   if (UseNewSROA)
 185     MPM.add(createSROAPass(/*RequiresDomTree*/ false));
 186   else
 187     MPM.add(createScalarReplAggregatesPass(-1, false));
 188   MPM.add(createEarlyCSEPass());              // Catch trivial redundancies
 189   MPM.add(createJumpThreadingPass());         // Thread jumps.
 190   MPM.add(createCorrelatedValuePropagationPass()); // Propagate conditionals
 191   MPM.add(createCFGSimplificationPass());     // Merge & remove BBs
 192   MPM.add(createInstructionCombiningPass());  // Combine silly seq's
 193   addExtensionsToPM(EP_Peephole, MPM);
 194
 195   if (!DisableTailCalls)
 196     MPM.add(createTailCallEliminationPass()); // Eliminate tail calls
 197   MPM.add(createCFGSimplificationPass());     // Merge & remove BBs
 198   MPM.add(createReassociatePass());           // Reassociate expressions
 199   MPM.add(createLoopRotatePass());            // Rotate Loop
 200   MPM.add(createLICMPass());                  // Hoist loop invariants
 201   MPM.add(createLoopUnswitchPass(SizeLevel || OptLevel < 3));
 202   MPM.add(createInstructionCombiningPass());
 203   MPM.add(createIndVarSimplifyPass());        // Canonicalize indvars
 204   MPM.add(createLoopIdiomPass());             // Recognize idioms like memset.
 205   MPM.add(createLoopDeletionPass());          // Delete dead loops
 206
 207   if (!DisableUnrollLoops)
 208     MPM.add(createSimpleLoopUnrollPass());    // Unroll small loops
 209   addExtensionsToPM(EP_LoopOptimizerEnd, MPM);
 210
 211   if (OptLevel > 1) {
 212     MPM.add(createMergedLoadStoreMotionPass()); // Merge load/stores in diamond
 213     MPM.add(createGVNPass());                 // Remove redundancies
 214   }
 215   MPM.add(createMemCpyOptPass());             // Remove memcpy / form memset
 216   MPM.add(createSCCPPass());                  // Constant prop with SCCP
 217
 218   // Run instcombine after redundancy elimination to exploit opportunities
 219   // opened up by them.
 220   MPM.add(createInstructionCombiningPass());
 221   addExtensionsToPM(EP_Peephole, MPM);
 222   MPM.add(createJumpThreadingPass());         // Thread jumps
 223   MPM.add(createCorrelatedValuePropagationPass());
 224   MPM.add(createDeadStoreEliminationPass());  // Delete dead stores
 225
 226   addExtensionsToPM(EP_ScalarOptimizerLate, MPM);
 227
 228   if (RerollLoops)
 229     MPM.add(createLoopRerollPass());
 230   if (SLPVectorize)
 231     MPM.add(createSLPVectorizerPass());   // Vectorize parallel scalar chains.
 232
 233   if (BBVectorize) {
 234     MPM.add(createBBVectorizePass());
 235     MPM.add(createInstructionCombiningPass());
 236     addExtensionsToPM(EP_Peephole, MPM);
 237     if (OptLevel > 1 && UseGVNAfterVectorization)
 238       MPM.add(createGVNPass());           // Remove redundancies
 239     else
 240       MPM.add(createEarlyCSEPass());      // Catch trivial redundancies
 241
 242     // BBVectorize may have significantly shortened a loop body; unroll again.
 243     if (!DisableUnrollLoops)
 244       MPM.add(createLoopUnrollPass());
 245   }
 246
 247   if (LoadCombine)
 248     MPM.add(createLoadCombinePass());
 249
 250   MPM.add(createAggressiveDCEPass());         // Delete dead instructions
 251   MPM.add(createCFGSimplificationPass()); // Merge & remove BBs
 252   MPM.add(createInstructionCombiningPass());  // Clean up after everything.
 253   addExtensionsToPM(EP_Peephole, MPM);
 254
 255   // FIXME: This is a HACK! The inliner pass above implicitly creates a CGSCC
 256   // pass manager that we are specifically trying to avoid. To prevent this
 257   // we must insert a no-op module pass to reset the pass manager.
 258   MPM.add(createBarrierNoopPass());
 259   MPM.add(createLoopVectorizePass(DisableUnrollLoops, LoopVectorize));
 260   // FIXME: Because of #pragma vectorize enable, the passes below are always
 261   // inserted in the pipeline, even when the vectorizer doesn't run (ex. when
 262   // on -O1 and no #pragma is found). Would be good to have these two passes
 263   // as function calls, so that we can only pass them when the vectorizer
 264   // changed the code.
 265   MPM.add(createInstructionCombiningPass());
 266   addExtensionsToPM(EP_Peephole, MPM);
 267   MPM.add(createCFGSimplificationPass());
 268
 269   if (!DisableUnrollLoops)
 270     MPM.add(createLoopUnrollPass());    // Unroll small loops
 271
 272   if (!DisableUnitAtATime) {
 273     // FIXME: We shouldn't bother with this anymore.
 274     MPM.add(createStripDeadPrototypesPass()); // Get rid of dead prototypes
 275
 276     // GlobalOpt already deletes dead functions and globals, at -O2 try a
 277     // late pass of GlobalDCE.  It is capable of deleting dead cycles.
 278     if (OptLevel > 1) {
 279       MPM.add(createGlobalDCEPass());         // Remove dead fns and globals.
 280       MPM.add(createConstantMergePass());     // Merge dup global constants
 281     }
 282   }
 283   addExtensionsToPM(EP_OptimizerLast, MPM);
 284 }
 285
 286 void PassManagerBuilder::populateLTOPassManager(PassManagerBase &PM,
 287                                                 bool Internalize,
 288                                                 bool RunInliner,
 289                                                 bool DisableGVNLoadPRE) {
 290   // Provide AliasAnalysis services for optimizations.
 291   addInitialAliasAnalysisPasses(PM);
 292
 293   // Now that composite has been compiled, scan through the module, looking
 294   // for a main function.  If main is defined, mark all other functions
 295   // internal.
 296   if (Internalize)
 297     PM.add(createInternalizePass("main"));
 298
 299   // Propagate constants at call sites into the functions they call.  This
 300   // opens opportunities for globalopt (and inlining) by substituting function
 301   // pointers passed as arguments to direct uses of functions.
 302   PM.add(createIPSCCPPass());
 303
 304   // Now that we internalized some globals, see if we can hack on them!
 305   PM.add(createGlobalOptimizerPass());
 306
 307   // Linking modules together can lead to duplicated global constants, only
 308   // keep one copy of each constant.
 309   PM.add(createConstantMergePass());
 310
 311   // Remove unused arguments from functions.
 312   PM.add(createDeadArgEliminationPass());
 313
 314   // Reduce the code after globalopt and ipsccp.  Both can open up significant
 315   // simplification opportunities, and both can propagate functions through
 316   // function pointers.  When this happens, we often have to resolve varargs
 317   // calls, etc, so let instcombine do this.
 318   PM.add(createInstructionCombiningPass());
 319   addExtensionsToPM(EP_Peephole, PM);
 320
 321   // Inline small functions
 322   if (RunInliner)
 323     PM.add(createFunctionInliningPass());
 324
 325   PM.add(createPruneEHPass());   // Remove dead EH info.
 326
 327   // Optimize globals again if we ran the inliner.
 328   if (RunInliner)
 329     PM.add(createGlobalOptimizerPass());
 330   PM.add(createGlobalDCEPass()); // Remove dead functions.
 331
 332   // If we didn't decide to inline a function, check to see if we can
 333   // transform it to pass arguments by value instead of by reference.
 334   PM.add(createArgumentPromotionPass());
 335
 336   // The IPO passes may leave cruft around.  Clean up after them.
 337   PM.add(createInstructionCombiningPass());
 338   addExtensionsToPM(EP_Peephole, PM);
 339   PM.add(createJumpThreadingPass());
 340
 341   // Break up allocas
 342   if (UseNewSROA)
 343     PM.add(createSROAPass());
 344   else
 345     PM.add(createScalarReplAggregatesPass());
 346
 347   // Run a few AA driven optimizations here and now, to cleanup the code.
 348   PM.add(createFunctionAttrsPass()); // Add nocapture.
 349   PM.add(createGlobalsModRefPass()); // IP alias analysis.
 350
 351   PM.add(createLICMPass());                 // Hoist loop invariants.
 352   PM.add(createMergedLoadStoreMotionPass()); // Merge load/stores in diamonds
 353   PM.add(createGVNPass(DisableGVNLoadPRE)); // Remove redundancies.
 354   PM.add(createMemCpyOptPass());            // Remove dead memcpys.
 355
 356   // Nuke dead stores.
 357   PM.add(createDeadStoreEliminationPass());
 358
 359   // More loops are countable; try to optimize them.
 360   PM.add(createIndVarSimplifyPass());
 361   PM.add(createLoopDeletionPass());
 362   PM.add(createLoopVectorizePass(true, true));
 363
 364   // More scalar chains could be vectorized due to more alias information
 365   PM.add(createSLPVectorizerPass()); // Vectorize parallel scalar chains.
 366
 367   if (LoadCombine)
 368     PM.add(createLoadCombinePass());
 369
 370   // Cleanup and simplify the code after the scalar optimizations.
 371   PM.add(createInstructionCombiningPass());
 372   addExtensionsToPM(EP_Peephole, PM);
 373
 374   PM.add(createJumpThreadingPass());
 375
 376   // Delete basic blocks, which optimization passes may have killed.
 377   PM.add(createCFGSimplificationPass());
 378
 379   // Now that we have optimized the program, discard unreachable functions.
 380   PM.add(createGlobalDCEPass());
 381 }
 382
 383 inline PassManagerBuilder *unwrap(LLVMPassManagerBuilderRef P) {
 384     return reinterpret_cast<PassManagerBuilder*>(P);
 385 }
 386
 387 inline LLVMPassManagerBuilderRef wrap(PassManagerBuilder *P) {
 388   return reinterpret_cast<LLVMPassManagerBuilderRef>(P);
 389 }
 390
 391 LLVMPassManagerBuilderRef LLVMPassManagerBuilderCreate() {
 392   PassManagerBuilder *PMB = new PassManagerBuilder();
 393   return wrap(PMB);
 394 }
 395
 396 void LLVMPassManagerBuilderDispose(LLVMPassManagerBuilderRef PMB) {
 397   PassManagerBuilder *Builder = unwrap(PMB);
 398   delete Builder;
 399 }
 400
 401 void
 402 LLVMPassManagerBuilderSetOptLevel(LLVMPassManagerBuilderRef PMB,
 403                                   unsigned OptLevel) {
 404   PassManagerBuilder *Builder = unwrap(PMB);
 405   Builder->OptLevel = OptLevel;
 406 }
 407
 408 void
 409 LLVMPassManagerBuilderSetSizeLevel(LLVMPassManagerBuilderRef PMB,
 410                                    unsigned SizeLevel) {
 411   PassManagerBuilder *Builder = unwrap(PMB);
 412   Builder->SizeLevel = SizeLevel;
 413 }
 414
 415 void
 416 LLVMPassManagerBuilderSetDisableUnitAtATime(LLVMPassManagerBuilderRef PMB,
 417                                             LLVMBool Value) {
 418   PassManagerBuilder *Builder = unwrap(PMB);
 419   Builder->DisableUnitAtATime = Value;
 420 }
 421
 422 void
 423 LLVMPassManagerBuilderSetDisableUnrollLoops(LLVMPassManagerBuilderRef PMB,
 424                                             LLVMBool Value) {
 425   PassManagerBuilder *Builder = unwrap(PMB);
 426   Builder->DisableUnrollLoops = Value;
 427 }
 428
 429 void
 430 LLVMPassManagerBuilderSetDisableSimplifyLibCalls(LLVMPassManagerBuilderRef PMB,
 431                                                  LLVMBool Value) {
 432   // NOTE: The simplify-libcalls pass has been removed.
 433 }
 434
 435 void
 436 LLVMPassManagerBuilderUseInlinerWithThreshold(LLVMPassManagerBuilderRef PMB,
 437                                               unsigned Threshold) {
 438   PassManagerBuilder *Builder = unwrap(PMB);
 439   Builder->Inliner = createFunctionInliningPass(Threshold);
 440 }
 441
 442 void
 443 LLVMPassManagerBuilderPopulateFunctionPassManager(LLVMPassManagerBuilderRef PMB,
 444                                                   LLVMPassManagerRef PM) {
 445   PassManagerBuilder *Builder = unwrap(PMB);
 446   FunctionPassManager *FPM = unwrap<FunctionPassManager>(PM);
 447   Builder->populateFunctionPassManager(*FPM);
 448 }
 449
 450 void
 451 LLVMPassManagerBuilderPopulateModulePassManager(LLVMPassManagerBuilderRef PMB,
 452                                                 LLVMPassManagerRef PM) {
 453   PassManagerBuilder *Builder = unwrap(PMB);
 454   PassManagerBase *MPM = unwrap(PM);
 455   Builder->populateModulePassManager(*MPM);
 456 }
 457
 458 void LLVMPassManagerBuilderPopulateLTOPassManager(LLVMPassManagerBuilderRef PMB,
 459                                                   LLVMPassManagerRef PM,
 460                                                   LLVMBool Internalize,
 461                                                   LLVMBool RunInliner) {
 462   PassManagerBuilder *Builder = unwrap(PMB);
 463   PassManagerBase *LPM = unwrap(PM);
 464   Builder->populateLTOPassManager(*LPM, Internalize != 0, RunInliner != 0);
 465 }