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/Analysis/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",
  33                      cl::desc("Run the Loop vectorization passes"));
  34
  35 // This is a helper flag that we use for testing the profitability of
  36 // vectorization on -O2 and -Os. It should go away once we make a decision.
  37 static cl::opt<bool>
  38 VectorizeO2("vectorize-o2",
  39             cl::desc("Enable vectorization on all O levels"));
  40
  41 static cl::opt<bool>
  42 RunSLPVectorization("vectorize-slp",
  43                     cl::desc("Run the SLP vectorization passes"));
  44
  45 static cl::opt<bool>
  46 RunBBVectorization("vectorize-slp-aggressive",
  47                     cl::desc("Run the BB vectorization passes"));
  48
  49 static cl::opt<bool>
  50 UseGVNAfterVectorization("use-gvn-after-vectorization",
  51   cl::init(false), cl::Hidden,
  52   cl::desc("Run GVN instead of Early CSE after vectorization passes"));
  53
  54 static cl::opt<bool> UseNewSROA("use-new-sroa",
  55   cl::init(true), cl::Hidden,
  56   cl::desc("Enable the new, experimental SROA pass"));
  57
  58 PassManagerBuilder::PassManagerBuilder() {
  59     OptLevel = 2;
  60     SizeLevel = 0;
  61     LibraryInfo = 0;
  62     Inliner = 0;
  63     DisableSimplifyLibCalls = false;
  64     DisableUnitAtATime = false;
  65     DisableUnrollLoops = false;
  66     BBVectorize = RunBBVectorization;
  67     SLPVectorize = RunSLPVectorization;
  68     LoopVectorize = RunLoopVectorization;
  69 }
  70
  71 PassManagerBuilder::~PassManagerBuilder() {
  72   delete LibraryInfo;
  73   delete Inliner;
  74 }
  75
  76 /// Set of global extensions, automatically added as part of the standard set.
  77 static ManagedStatic<SmallVector<std::pair<PassManagerBuilder::ExtensionPointTy,
  78    PassManagerBuilder::ExtensionFn>, 8> > GlobalExtensions;
  79
  80 void PassManagerBuilder::addGlobalExtension(
  81     PassManagerBuilder::ExtensionPointTy Ty,
  82     PassManagerBuilder::ExtensionFn Fn) {
  83   GlobalExtensions->push_back(std::make_pair(Ty, Fn));
  84 }
  85
  86 void PassManagerBuilder::addExtension(ExtensionPointTy Ty, ExtensionFn Fn) {
  87   Extensions.push_back(std::make_pair(Ty, Fn));
  88 }
  89
  90 void PassManagerBuilder::addExtensionsToPM(ExtensionPointTy ETy,
  91                                            PassManagerBase &PM) const {
  92   for (unsigned i = 0, e = GlobalExtensions->size(); i != e; ++i)
  93     if ((*GlobalExtensions)[i].first == ETy)
  94       (*GlobalExtensions)[i].second(*this, PM);
  95   for (unsigned i = 0, e = Extensions.size(); i != e; ++i)
  96     if (Extensions[i].first == ETy)
  97       Extensions[i].second(*this, PM);
  98 }
  99
 100 void
 101 PassManagerBuilder::addInitialAliasAnalysisPasses(PassManagerBase &PM) const {
 102   // Add TypeBasedAliasAnalysis before BasicAliasAnalysis so that
 103   // BasicAliasAnalysis wins if they disagree. This is intended to help
 104   // support "obvious" type-punning idioms.
 105   PM.add(createTypeBasedAliasAnalysisPass());
 106   PM.add(createBasicAliasAnalysisPass());
 107 }
 108
 109 void PassManagerBuilder::populateFunctionPassManager(FunctionPassManager &FPM) {
 110   addExtensionsToPM(EP_EarlyAsPossible, FPM);
 111
 112   // Add LibraryInfo if we have some.
 113   if (LibraryInfo) FPM.add(new TargetLibraryInfo(*LibraryInfo));
 114
 115   if (OptLevel == 0) return;
 116
 117   addInitialAliasAnalysisPasses(FPM);
 118
 119   FPM.add(createCFGSimplificationPass());
 120   if (UseNewSROA)
 121     FPM.add(createSROAPass());
 122   else
 123     FPM.add(createScalarReplAggregatesPass());
 124   FPM.add(createEarlyCSEPass());
 125   FPM.add(createLowerExpectIntrinsicPass());
 126 }
 127
 128 void PassManagerBuilder::populateModulePassManager(PassManagerBase &MPM) {
 129   // If all optimizations are disabled, just run the always-inline pass.
 130   if (OptLevel == 0) {
 131     if (Inliner) {
 132       MPM.add(Inliner);
 133       Inliner = 0;
 134     }
 135
 136     // FIXME: This is a HACK! The inliner pass above implicitly creates a CGSCC
 137     // pass manager, but we don't want to add extensions into that pass manager.
 138     // To prevent this we must insert a no-op module pass to reset the pass
 139     // manager to get the same behavior as EP_OptimizerLast in non-O0 builds.
 140     if (!GlobalExtensions->empty() || !Extensions.empty())
 141       MPM.add(createBarrierNoopPass());
 142
 143     addExtensionsToPM(EP_EnabledOnOptLevel0, MPM);
 144     return;
 145   }
 146
 147   // Add LibraryInfo if we have some.
 148   if (LibraryInfo) MPM.add(new TargetLibraryInfo(*LibraryInfo));
 149
 150   addInitialAliasAnalysisPasses(MPM);
 151
 152   if (!DisableUnitAtATime) {
 153     addExtensionsToPM(EP_ModuleOptimizerEarly, MPM);
 154
 155     MPM.add(createGlobalOptimizerPass());     // Optimize out global vars
 156
 157     MPM.add(createIPSCCPPass());              // IP SCCP
 158     MPM.add(createDeadArgEliminationPass());  // Dead argument elimination
 159
 160     MPM.add(createInstructionCombiningPass());// Clean up after IPCP & DAE
 161     MPM.add(createCFGSimplificationPass());   // Clean up after IPCP & DAE
 162   }
 163
 164   // Start of CallGraph SCC passes.
 165   if (!DisableUnitAtATime)
 166     MPM.add(createPruneEHPass());             // Remove dead EH info
 167   if (Inliner) {
 168     MPM.add(Inliner);
 169     Inliner = 0;
 170   }
 171   if (!DisableUnitAtATime)
 172     MPM.add(createFunctionAttrsPass());       // Set readonly/readnone attrs
 173   if (OptLevel > 2)
 174     MPM.add(createArgumentPromotionPass());   // Scalarize uninlined fn args
 175
 176   // Start of function pass.
 177   // Break up aggregate allocas, using SSAUpdater.
 178   if (UseNewSROA)
 179     MPM.add(createSROAPass(/*RequiresDomTree*/ false));
 180   else
 181     MPM.add(createScalarReplAggregatesPass(-1, false));
 182   MPM.add(createEarlyCSEPass());              // Catch trivial redundancies
 183   if (!DisableSimplifyLibCalls)
 184     MPM.add(createSimplifyLibCallsPass());    // Library Call Optimizations
 185   MPM.add(createJumpThreadingPass());         // Thread jumps.
 186   MPM.add(createCorrelatedValuePropagationPass()); // Propagate conditionals
 187   MPM.add(createCFGSimplificationPass());     // Merge & remove BBs
 188   MPM.add(createInstructionCombiningPass());  // Combine silly seq's
 189
 190   MPM.add(createTailCallEliminationPass());   // Eliminate tail calls
 191   MPM.add(createCFGSimplificationPass());     // Merge & remove BBs
 192   MPM.add(createReassociatePass());           // Reassociate expressions
 193   MPM.add(createLoopRotatePass());            // Rotate Loop
 194   MPM.add(createLICMPass());                  // Hoist loop invariants
 195   MPM.add(createLoopUnswitchPass(SizeLevel || OptLevel < 3));
 196   MPM.add(createInstructionCombiningPass());
 197   MPM.add(createIndVarSimplifyPass());        // Canonicalize indvars
 198   MPM.add(createLoopIdiomPass());             // Recognize idioms like memset.
 199   MPM.add(createLoopDeletionPass());          // Delete dead loops
 200
 201   if (LoopVectorize && (OptLevel > 2 || VectorizeO2))
 202     MPM.add(createLoopVectorizePass());
 203
 204   if (!DisableUnrollLoops)
 205     MPM.add(createLoopUnrollPass());          // Unroll small loops
 206   addExtensionsToPM(EP_LoopOptimizerEnd, MPM);
 207
 208   if (OptLevel > 1)
 209     MPM.add(createGVNPass());                 // Remove redundancies
 210   MPM.add(createMemCpyOptPass());             // Remove memcpy / form memset
 211   MPM.add(createSCCPPass());                  // Constant prop with SCCP
 212
 213   // Run instcombine after redundancy elimination to exploit opportunities
 214   // opened up by them.
 215   MPM.add(createInstructionCombiningPass());
 216   MPM.add(createJumpThreadingPass());         // Thread jumps
 217   MPM.add(createCorrelatedValuePropagationPass());
 218   MPM.add(createDeadStoreEliminationPass());  // Delete dead stores
 219
 220   addExtensionsToPM(EP_ScalarOptimizerLate, MPM);
 221
 222   if (SLPVectorize)
 223     MPM.add(createSLPVectorizerPass());     // Vectorize parallel scalar chains.
 224
 225   if (BBVectorize) {
 226     MPM.add(createBBVectorizePass());
 227     MPM.add(createInstructionCombiningPass());
 228     if (OptLevel > 1 && UseGVNAfterVectorization)
 229       MPM.add(createGVNPass());                   // Remove redundancies
 230     else
 231       MPM.add(createEarlyCSEPass());              // Catch trivial redundancies
 232
 233     // BBVectorize may have significantly shortened a loop body; unroll again.
 234     if (!DisableUnrollLoops)
 235       MPM.add(createLoopUnrollPass());
 236   }
 237
 238   MPM.add(createAggressiveDCEPass());         // Delete dead instructions
 239   MPM.add(createCFGSimplificationPass());     // Merge & remove BBs
 240   MPM.add(createInstructionCombiningPass());  // Clean up after everything.
 241
 242   if (!DisableUnitAtATime) {
 243     // FIXME: We shouldn't bother with this anymore.
 244     MPM.add(createStripDeadPrototypesPass()); // Get rid of dead prototypes
 245
 246     // GlobalOpt already deletes dead functions and globals, at -O2 try a
 247     // late pass of GlobalDCE.  It is capable of deleting dead cycles.
 248     if (OptLevel > 1) {
 249       MPM.add(createGlobalDCEPass());         // Remove dead fns and globals.
 250       MPM.add(createConstantMergePass());     // Merge dup global constants
 251     }
 252   }
 253   addExtensionsToPM(EP_OptimizerLast, MPM);
 254 }
 255
 256 void PassManagerBuilder::populateLTOPassManager(PassManagerBase &PM,
 257                                                 bool Internalize,
 258                                                 bool RunInliner,
 259                                                 bool DisableGVNLoadPRE) {
 260   // Provide AliasAnalysis services for optimizations.
 261   addInitialAliasAnalysisPasses(PM);
 262
 263   // Now that composite has been compiled, scan through the module, looking
 264   // for a main function.  If main is defined, mark all other functions
 265   // internal.
 266   if (Internalize) {
 267     std::vector<const char*> E;
 268     E.push_back("main");
 269     PM.add(createInternalizePass(E));
 270   }
 271
 272   // Propagate constants at call sites into the functions they call.  This
 273   // opens opportunities for globalopt (and inlining) by substituting function
 274   // pointers passed as arguments to direct uses of functions.
 275   PM.add(createIPSCCPPass());
 276
 277   // Now that we internalized some globals, see if we can hack on them!
 278   PM.add(createGlobalOptimizerPass());
 279
 280   // Linking modules together can lead to duplicated global constants, only
 281   // keep one copy of each constant.
 282   PM.add(createConstantMergePass());
 283
 284   // Remove unused arguments from functions.
 285   PM.add(createDeadArgEliminationPass());
 286
 287   // Reduce the code after globalopt and ipsccp.  Both can open up significant
 288   // simplification opportunities, and both can propagate functions through
 289   // function pointers.  When this happens, we often have to resolve varargs
 290   // calls, etc, so let instcombine do this.
 291   PM.add(createInstructionCombiningPass());
 292
 293   // Inline small functions
 294   if (RunInliner)
 295     PM.add(createFunctionInliningPass());
 296
 297   PM.add(createPruneEHPass());   // Remove dead EH info.
 298
 299   // Optimize globals again if we ran the inliner.
 300   if (RunInliner)
 301     PM.add(createGlobalOptimizerPass());
 302   PM.add(createGlobalDCEPass()); // Remove dead functions.
 303
 304   // If we didn't decide to inline a function, check to see if we can
 305   // transform it to pass arguments by value instead of by reference.
 306   PM.add(createArgumentPromotionPass());
 307
 308   // The IPO passes may leave cruft around.  Clean up after them.
 309   PM.add(createInstructionCombiningPass());
 310   PM.add(createJumpThreadingPass());
 311   // Break up allocas
 312   if (UseNewSROA)
 313     PM.add(createSROAPass());
 314   else
 315     PM.add(createScalarReplAggregatesPass());
 316
 317   // Run a few AA driven optimizations here and now, to cleanup the code.
 318   PM.add(createFunctionAttrsPass()); // Add nocapture.
 319   PM.add(createGlobalsModRefPass()); // IP alias analysis.
 320
 321   PM.add(createLICMPass());                 // Hoist loop invariants.
 322   PM.add(createGVNPass(DisableGVNLoadPRE)); // Remove redundancies.
 323   PM.add(createMemCpyOptPass());            // Remove dead memcpys.
 324   // Nuke dead stores.
 325   PM.add(createDeadStoreEliminationPass());
 326
 327   // Cleanup and simplify the code after the scalar optimizations.
 328   PM.add(createInstructionCombiningPass());
 329
 330   PM.add(createJumpThreadingPass());
 331
 332   // Delete basic blocks, which optimization passes may have killed.
 333   PM.add(createCFGSimplificationPass());
 334
 335   // Now that we have optimized the program, discard unreachable functions.
 336   PM.add(createGlobalDCEPass());
 337 }
 338
 339 inline PassManagerBuilder *unwrap(LLVMPassManagerBuilderRef P) {
 340     return reinterpret_cast<PassManagerBuilder*>(P);
 341 }
 342
 343 inline LLVMPassManagerBuilderRef wrap(PassManagerBuilder *P) {
 344   return reinterpret_cast<LLVMPassManagerBuilderRef>(P);
 345 }
 346
 347 LLVMPassManagerBuilderRef LLVMPassManagerBuilderCreate() {
 348   PassManagerBuilder *PMB = new PassManagerBuilder();
 349   return wrap(PMB);
 350 }
 351
 352 void LLVMPassManagerBuilderDispose(LLVMPassManagerBuilderRef PMB) {
 353   PassManagerBuilder *Builder = unwrap(PMB);
 354   delete Builder;
 355 }
 356
 357 void
 358 LLVMPassManagerBuilderSetOptLevel(LLVMPassManagerBuilderRef PMB,
 359                                   unsigned OptLevel) {
 360   PassManagerBuilder *Builder = unwrap(PMB);
 361   Builder->OptLevel = OptLevel;
 362 }
 363
 364 void
 365 LLVMPassManagerBuilderSetSizeLevel(LLVMPassManagerBuilderRef PMB,
 366                                    unsigned SizeLevel) {
 367   PassManagerBuilder *Builder = unwrap(PMB);
 368   Builder->SizeLevel = SizeLevel;
 369 }
 370
 371 void
 372 LLVMPassManagerBuilderSetDisableUnitAtATime(LLVMPassManagerBuilderRef PMB,
 373                                             LLVMBool Value) {
 374   PassManagerBuilder *Builder = unwrap(PMB);
 375   Builder->DisableUnitAtATime = Value;
 376 }
 377
 378 void
 379 LLVMPassManagerBuilderSetDisableUnrollLoops(LLVMPassManagerBuilderRef PMB,
 380                                             LLVMBool Value) {
 381   PassManagerBuilder *Builder = unwrap(PMB);
 382   Builder->DisableUnrollLoops = Value;
 383 }
 384
 385 void
 386 LLVMPassManagerBuilderSetDisableSimplifyLibCalls(LLVMPassManagerBuilderRef PMB,
 387                                                  LLVMBool Value) {
 388   PassManagerBuilder *Builder = unwrap(PMB);
 389   Builder->DisableSimplifyLibCalls = Value;
 390 }
 391
 392 void
 393 LLVMPassManagerBuilderUseInlinerWithThreshold(LLVMPassManagerBuilderRef PMB,
 394                                               unsigned Threshold) {
 395   PassManagerBuilder *Builder = unwrap(PMB);
 396   Builder->Inliner = createFunctionInliningPass(Threshold);
 397 }
 398
 399 void
 400 LLVMPassManagerBuilderPopulateFunctionPassManager(LLVMPassManagerBuilderRef PMB,
 401                                                   LLVMPassManagerRef PM) {
 402   PassManagerBuilder *Builder = unwrap(PMB);
 403   FunctionPassManager *FPM = unwrap<FunctionPassManager>(PM);
 404   Builder->populateFunctionPassManager(*FPM);
 405 }
 406
 407 void
 408 LLVMPassManagerBuilderPopulateModulePassManager(LLVMPassManagerBuilderRef PMB,
 409                                                 LLVMPassManagerRef PM) {
 410   PassManagerBuilder *Builder = unwrap(PMB);
 411   PassManagerBase *MPM = unwrap(PM);
 412   Builder->populateModulePassManager(*MPM);
 413 }
 414
 415 void LLVMPassManagerBuilderPopulateLTOPassManager(LLVMPassManagerBuilderRef PMB,
 416                                                   LLVMPassManagerRef PM,
 417                                                   LLVMBool Internalize,
 418                                                   LLVMBool RunInliner) {
 419   PassManagerBuilder *Builder = unwrap(PMB);
 420   PassManagerBase *LPM = unwrap(PM);
 421   Builder->populateLTOPassManager(*LPM, Internalize != 0, RunInliner != 0);
 422 }