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