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