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
  18 #include "llvm-c/Transforms/PassManagerBuilder.h"
  19
  20 #include "llvm/PassManager.h"
  21 #include "llvm/DefaultPasses.h"
  22 #include "llvm/PassManager.h"
  23 #include "llvm/Analysis/Passes.h"
  24 #include "llvm/Analysis/Verifier.h"
  25 #include "llvm/Support/CommandLine.h"
  26 #include "llvm/Target/TargetLibraryInfo.h"
  27 #include "llvm/Transforms/Scalar.h"
  28 #include "llvm/Transforms/Vectorize.h"
  29 #include "llvm/Transforms/IPO.h"
  30 #include "llvm/ADT/SmallVector.h"
  31 #include "llvm/Support/ManagedStatic.h"
  32
  33 using namespace llvm;
  34
  35 static cl::opt<bool>
  36 RunVectorization("vectorize", cl::desc("Run vectorization passes"));
  37
  38 static cl::opt<bool>
  39 UseGVNAfterVectorization("use-gvn-after-vectorization",
  40   cl::init(false), cl::Hidden,
  41   cl::desc("Run GVN instead of Early CSE after vectorization passes"));
  42
  43 static cl::opt<bool> UseNewSROA("use-new-sroa",
  44   cl::init(true), cl::Hidden,
  45   cl::desc("Enable the new, experimental SROA pass"));
  46
  47 PassManagerBuilder::PassManagerBuilder() {
  48     OptLevel = 2;
  49     SizeLevel = 0;
  50     LibraryInfo = 0;
  51     Inliner = 0;
  52     DisableSimplifyLibCalls = false;
  53     DisableUnitAtATime = false;
  54     DisableUnrollLoops = false;
  55     Vectorize = RunVectorization;
  56 }
  57
  58 PassManagerBuilder::~PassManagerBuilder() {
  59   delete LibraryInfo;
  60   delete Inliner;
  61 }
  62
  63 /// Set of global extensions, automatically added as part of the standard set.
  64 static ManagedStatic<SmallVector<std::pair<PassManagerBuilder::ExtensionPointTy,
  65    PassManagerBuilder::ExtensionFn>, 8> > GlobalExtensions;
  66
  67 void PassManagerBuilder::addGlobalExtension(
  68     PassManagerBuilder::ExtensionPointTy Ty,
  69     PassManagerBuilder::ExtensionFn Fn) {
  70   GlobalExtensions->push_back(std::make_pair(Ty, Fn));
  71 }
  72
  73 void PassManagerBuilder::addExtension(ExtensionPointTy Ty, ExtensionFn Fn) {
  74   Extensions.push_back(std::make_pair(Ty, Fn));
  75 }
  76
  77 void PassManagerBuilder::addExtensionsToPM(ExtensionPointTy ETy,
  78                                            PassManagerBase &PM) const {
  79   for (unsigned i = 0, e = GlobalExtensions->size(); i != e; ++i)
  80     if ((*GlobalExtensions)[i].first == ETy)
  81       (*GlobalExtensions)[i].second(*this, PM);
  82   for (unsigned i = 0, e = Extensions.size(); i != e; ++i)
  83     if (Extensions[i].first == ETy)
  84       Extensions[i].second(*this, PM);
  85 }
  86
  87 void
  88 PassManagerBuilder::addInitialAliasAnalysisPasses(PassManagerBase &PM) const {
  89   // Add TypeBasedAliasAnalysis before BasicAliasAnalysis so that
  90   // BasicAliasAnalysis wins if they disagree. This is intended to help
  91   // support "obvious" type-punning idioms.
  92   PM.add(createTypeBasedAliasAnalysisPass());
  93   PM.add(createBasicAliasAnalysisPass());
  94 }
  95
  96 void PassManagerBuilder::populateFunctionPassManager(FunctionPassManager &FPM) {
  97   addExtensionsToPM(EP_EarlyAsPossible, FPM);
  98
  99   // Add LibraryInfo if we have some.
 100   if (LibraryInfo) FPM.add(new TargetLibraryInfo(*LibraryInfo));
 101
 102   if (OptLevel == 0) return;
 103
 104   addInitialAliasAnalysisPasses(FPM);
 105
 106   FPM.add(createCFGSimplificationPass());
 107   if (UseNewSROA)
 108     FPM.add(createSROAPass());
 109   else
 110     FPM.add(createScalarReplAggregatesPass());
 111   FPM.add(createEarlyCSEPass());
 112   FPM.add(createLowerExpectIntrinsicPass());
 113 }
 114
 115 void PassManagerBuilder::populateModulePassManager(PassManagerBase &MPM) {
 116   // If all optimizations are disabled, just run the always-inline pass.
 117   if (OptLevel == 0) {
 118     if (Inliner) {
 119       MPM.add(Inliner);
 120       Inliner = 0;
 121     }
 122
 123     // FIXME: This is a HACK! The inliner pass above implicitly creates a CGSCC
 124     // pass manager, but we don't want to add extensions into that pass manager.
 125     // To prevent this we must insert a no-op module pass to reset the pass
 126     // manager to get the same behavior as EP_OptimizerLast in non-O0 builds.
 127     if (!GlobalExtensions->empty() || !Extensions.empty())
 128       MPM.add(createBarrierNoopPass());
 129
 130     addExtensionsToPM(EP_EnabledOnOptLevel0, MPM);
 131     return;
 132   }
 133
 134   // Add LibraryInfo if we have some.
 135   if (LibraryInfo) MPM.add(new TargetLibraryInfo(*LibraryInfo));
 136
 137   addInitialAliasAnalysisPasses(MPM);
 138
 139   if (!DisableUnitAtATime) {
 140     addExtensionsToPM(EP_ModuleOptimizerEarly, MPM);
 141
 142     MPM.add(createGlobalOptimizerPass());     // Optimize out global vars
 143
 144     MPM.add(createIPSCCPPass());              // IP SCCP
 145     MPM.add(createDeadArgEliminationPass());  // Dead argument elimination
 146
 147     MPM.add(createInstructionCombiningPass());// Clean up after IPCP & DAE
 148     MPM.add(createCFGSimplificationPass());   // Clean up after IPCP & DAE
 149   }
 150
 151   // Start of CallGraph SCC passes.
 152   if (!DisableUnitAtATime)
 153     MPM.add(createPruneEHPass());             // Remove dead EH info
 154   if (Inliner) {
 155     MPM.add(Inliner);
 156     Inliner = 0;
 157   }
 158   if (!DisableUnitAtATime)
 159     MPM.add(createFunctionAttrsPass());       // Set readonly/readnone attrs
 160   if (OptLevel > 2)
 161     MPM.add(createArgumentPromotionPass());   // Scalarize uninlined fn args
 162
 163   // Start of function pass.
 164   // Break up aggregate allocas, using SSAUpdater.
 165   if (UseNewSROA)
 166     MPM.add(createSROAPass(/*RequiresDomTree*/ false));
 167   else
 168     MPM.add(createScalarReplAggregatesPass(-1, false));
 169   MPM.add(createEarlyCSEPass());              // Catch trivial redundancies
 170   if (!DisableSimplifyLibCalls)
 171     MPM.add(createSimplifyLibCallsPass());    // Library Call Optimizations
 172   MPM.add(createJumpThreadingPass());         // Thread jumps.
 173   MPM.add(createCorrelatedValuePropagationPass()); // Propagate conditionals
 174   MPM.add(createCFGSimplificationPass());     // Merge & remove BBs
 175   MPM.add(createInstructionCombiningPass());  // Combine silly seq's
 176
 177   MPM.add(createTailCallEliminationPass());   // Eliminate tail calls
 178   MPM.add(createCFGSimplificationPass());     // Merge & remove BBs
 179   MPM.add(createReassociatePass());           // Reassociate expressions
 180   MPM.add(createLoopRotatePass());            // Rotate Loop
 181   MPM.add(createLICMPass());                  // Hoist loop invariants
 182   MPM.add(createLoopUnswitchPass(SizeLevel || OptLevel < 3));
 183   MPM.add(createInstructionCombiningPass());
 184   MPM.add(createIndVarSimplifyPass());        // Canonicalize indvars
 185   MPM.add(createLoopIdiomPass());             // Recognize idioms like memset.
 186   MPM.add(createLoopDeletionPass());          // Delete dead loops
 187
 188   if (Vectorize) {
 189     MPM.add(createLoopVectorizePass());
 190     MPM.add(createLICMPass());
 191   }
 192
 193   if (!DisableUnrollLoops)
 194     MPM.add(createLoopUnrollPass());          // Unroll small loops
 195   addExtensionsToPM(EP_LoopOptimizerEnd, MPM);
 196
 197   if (OptLevel > 1)
 198     MPM.add(createGVNPass());                 // Remove redundancies
 199   MPM.add(createMemCpyOptPass());             // Remove memcpy / form memset
 200   MPM.add(createSCCPPass());                  // Constant prop with SCCP
 201
 202   // Run instcombine after redundancy elimination to exploit opportunities
 203   // opened up by them.
 204   MPM.add(createInstructionCombiningPass());
 205   MPM.add(createJumpThreadingPass());         // Thread jumps
 206   MPM.add(createCorrelatedValuePropagationPass());
 207   MPM.add(createDeadStoreEliminationPass());  // Delete dead stores
 208
 209   addExtensionsToPM(EP_ScalarOptimizerLate, MPM);
 210
 211   if (Vectorize) {
 212     MPM.add(createBBVectorizePass());
 213     MPM.add(createInstructionCombiningPass());
 214     if (OptLevel > 1 && UseGVNAfterVectorization)
 215       MPM.add(createGVNPass());                   // Remove redundancies
 216     else
 217       MPM.add(createEarlyCSEPass());              // Catch trivial redundancies
 218   }
 219
 220   MPM.add(createAggressiveDCEPass());         // Delete dead instructions
 221   MPM.add(createCFGSimplificationPass());     // Merge & remove BBs
 222   MPM.add(createInstructionCombiningPass());  // Clean up after everything.
 223
 224   if (!DisableUnitAtATime) {
 225     // FIXME: We shouldn't bother with this anymore.
 226     MPM.add(createStripDeadPrototypesPass()); // Get rid of dead prototypes
 227
 228     // GlobalOpt already deletes dead functions and globals, at -O2 try a
 229     // late pass of GlobalDCE.  It is capable of deleting dead cycles.
 230     if (OptLevel > 1) {
 231       MPM.add(createGlobalDCEPass());         // Remove dead fns and globals.
 232       MPM.add(createConstantMergePass());     // Merge dup global constants
 233     }
 234   }
 235   addExtensionsToPM(EP_OptimizerLast, MPM);
 236 }
 237
 238 void PassManagerBuilder::populateLTOPassManager(PassManagerBase &PM,
 239                                                 bool Internalize,
 240                                                 bool RunInliner,
 241                                                 bool DisableGVNLoadPRE) {
 242   // Provide AliasAnalysis services for optimizations.
 243   addInitialAliasAnalysisPasses(PM);
 244
 245   // Now that composite has been compiled, scan through the module, looking
 246   // for a main function.  If main is defined, mark all other functions
 247   // internal.
 248   if (Internalize) {
 249     std::vector<const char*> E;
 250     E.push_back("main");
 251     PM.add(createInternalizePass(E));
 252   }
 253
 254   // Propagate constants at call sites into the functions they call.  This
 255   // opens opportunities for globalopt (and inlining) by substituting function
 256   // pointers passed as arguments to direct uses of functions.
 257   PM.add(createIPSCCPPass());
 258
 259   // Now that we internalized some globals, see if we can hack on them!
 260   PM.add(createGlobalOptimizerPass());
 261
 262   // Linking modules together can lead to duplicated global constants, only
 263   // keep one copy of each constant.
 264   PM.add(createConstantMergePass());
 265
 266   // Remove unused arguments from functions.
 267   PM.add(createDeadArgEliminationPass());
 268
 269   // Reduce the code after globalopt and ipsccp.  Both can open up significant
 270   // simplification opportunities, and both can propagate functions through
 271   // function pointers.  When this happens, we often have to resolve varargs
 272   // calls, etc, so let instcombine do this.
 273   PM.add(createInstructionCombiningPass());
 274
 275   // Inline small functions
 276   if (RunInliner)
 277     PM.add(createFunctionInliningPass());
 278
 279   PM.add(createPruneEHPass());   // Remove dead EH info.
 280
 281   // Optimize globals again if we ran the inliner.
 282   if (RunInliner)
 283     PM.add(createGlobalOptimizerPass());
 284   PM.add(createGlobalDCEPass()); // Remove dead functions.
 285
 286   // If we didn't decide to inline a function, check to see if we can
 287   // transform it to pass arguments by value instead of by reference.
 288   PM.add(createArgumentPromotionPass());
 289
 290   // The IPO passes may leave cruft around.  Clean up after them.
 291   PM.add(createInstructionCombiningPass());
 292   PM.add(createJumpThreadingPass());
 293   // Break up allocas
 294   if (UseNewSROA)
 295     PM.add(createSROAPass());
 296   else
 297     PM.add(createScalarReplAggregatesPass());
 298
 299   // Run a few AA driven optimizations here and now, to cleanup the code.
 300   PM.add(createFunctionAttrsPass()); // Add nocapture.
 301   PM.add(createGlobalsModRefPass()); // IP alias analysis.
 302
 303   PM.add(createLICMPass());                 // Hoist loop invariants.
 304   PM.add(createGVNPass(DisableGVNLoadPRE)); // Remove redundancies.
 305   PM.add(createMemCpyOptPass());            // Remove dead memcpys.
 306   // Nuke dead stores.
 307   PM.add(createDeadStoreEliminationPass());
 308
 309   // Cleanup and simplify the code after the scalar optimizations.
 310   PM.add(createInstructionCombiningPass());
 311
 312   PM.add(createJumpThreadingPass());
 313
 314   // Delete basic blocks, which optimization passes may have killed.
 315   PM.add(createCFGSimplificationPass());
 316
 317   // Now that we have optimized the program, discard unreachable functions.
 318   PM.add(createGlobalDCEPass());
 319 }
 320
 321 LLVMPassManagerBuilderRef LLVMPassManagerBuilderCreate(void) {
 322   PassManagerBuilder *PMB = new PassManagerBuilder();
 323   return wrap(PMB);
 324 }
 325
 326 void LLVMPassManagerBuilderDispose(LLVMPassManagerBuilderRef PMB) {
 327   PassManagerBuilder *Builder = unwrap(PMB);
 328   delete Builder;
 329 }
 330
 331 void
 332 LLVMPassManagerBuilderSetOptLevel(LLVMPassManagerBuilderRef PMB,
 333                                   unsigned OptLevel) {
 334   PassManagerBuilder *Builder = unwrap(PMB);
 335   Builder->OptLevel = OptLevel;
 336 }
 337
 338 void
 339 LLVMPassManagerBuilderSetSizeLevel(LLVMPassManagerBuilderRef PMB,
 340                                    unsigned SizeLevel) {
 341   PassManagerBuilder *Builder = unwrap(PMB);
 342   Builder->SizeLevel = SizeLevel;
 343 }
 344
 345 void
 346 LLVMPassManagerBuilderSetDisableUnitAtATime(LLVMPassManagerBuilderRef PMB,
 347                                             LLVMBool Value) {
 348   PassManagerBuilder *Builder = unwrap(PMB);
 349   Builder->DisableUnitAtATime = Value;
 350 }
 351
 352 void
 353 LLVMPassManagerBuilderSetDisableUnrollLoops(LLVMPassManagerBuilderRef PMB,
 354                                             LLVMBool Value) {
 355   PassManagerBuilder *Builder = unwrap(PMB);
 356   Builder->DisableUnrollLoops = Value;
 357 }
 358
 359 void
 360 LLVMPassManagerBuilderSetDisableSimplifyLibCalls(LLVMPassManagerBuilderRef PMB,
 361                                                  LLVMBool Value) {
 362   PassManagerBuilder *Builder = unwrap(PMB);
 363   Builder->DisableSimplifyLibCalls = Value;
 364 }
 365
 366 void
 367 LLVMPassManagerBuilderUseInlinerWithThreshold(LLVMPassManagerBuilderRef PMB,
 368                                               unsigned Threshold) {
 369   PassManagerBuilder *Builder = unwrap(PMB);
 370   Builder->Inliner = createFunctionInliningPass(Threshold);
 371 }
 372
 373 void
 374 LLVMPassManagerBuilderPopulateFunctionPassManager(LLVMPassManagerBuilderRef PMB,
 375                                                   LLVMPassManagerRef PM) {
 376   PassManagerBuilder *Builder = unwrap(PMB);
 377   FunctionPassManager *FPM = unwrap<FunctionPassManager>(PM);
 378   Builder->populateFunctionPassManager(*FPM);
 379 }
 380
 381 void
 382 LLVMPassManagerBuilderPopulateModulePassManager(LLVMPassManagerBuilderRef PMB,
 383                                                 LLVMPassManagerRef PM) {
 384   PassManagerBuilder *Builder = unwrap(PMB);
 385   PassManagerBase *MPM = unwrap(PM);
 386   Builder->populateModulePassManager(*MPM);
 387 }
 388
 389 void LLVMPassManagerBuilderPopulateLTOPassManager(LLVMPassManagerBuilderRef PMB,
 390                                                   LLVMPassManagerRef PM,
 391                                                   bool Internalize,
 392                                                   bool RunInliner) {
 393   PassManagerBuilder *Builder = unwrap(PMB);
 394   PassManagerBase *LPM = unwrap(PM);
 395   Builder->populateLTOPassManager(*LPM, Internalize, RunInliner);
 396 }