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