include/llvm/Support/StandardPasses.h

   1 //===-- llvm/Support/StandardPasses.h - Standard pass lists -----*- C++ -*-===//
   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 utility functions for creating a "standard" set of
  11 // optimization passes, so that compilers and tools which use optimization
  12 // passes use the same set of standard passes.
  13 //
  14 // These are implemented as inline functions so that we do not have to worry
  15 // about link issues.
  16 //
  17 //===----------------------------------------------------------------------===//
  18
  19 #ifndef LLVM_SUPPORT_STANDARDPASSES_H
  20 #define LLVM_SUPPORT_STANDARDPASSES_H
  21
  22 #include "llvm/PassManager.h"
  23 #include "llvm/Analysis/Dominators.h"
  24 #include "llvm/Analysis/Passes.h"
  25 #include "llvm/Analysis/Verifier.h"
  26 #include "llvm/Transforms/Scalar.h"
  27 #include "llvm/Transforms/IPO.h"
  28
  29 namespace llvm {
  30   /// createStandardFunctionPasses - Add the standard list of function passes to
  31   /// the provided pass manager.
  32   ///
  33   /// \arg OptimizationLevel - The optimization level, corresponding to -O0,
  34   /// -O1, etc.
  35   static inline void createStandardFunctionPasses(PassManagerBase *PM,
  36                                                   unsigned OptimizationLevel);
  37
  38   /// createStandardModulePasses - Add the standard list of module passes to the
  39   /// provided pass manager.
  40   ///
  41   /// \arg OptimizationLevel - The optimization level, corresponding to -O0,
  42   /// -O1, etc.
  43   /// \arg OptimizeSize - Whether the transformations should optimize for size.
  44   /// \arg UnitAtATime - Allow passes which may make global module changes.
  45   /// \arg UnrollLoops - Allow loop unrolling.
  46   /// \arg SimplifyLibCalls - Allow library calls to be simplified.
  47   /// \arg HaveExceptions - Whether the module may have code using exceptions.
  48   /// \arg InliningPass - The inlining pass to use, if any, or null. This will
  49   /// always be added, even at -O0.a
  50   static inline void createStandardModulePasses(PassManagerBase *PM,
  51                                                 unsigned OptimizationLevel,
  52                                                 bool OptimizeSize,
  53                                                 bool UnitAtATime,
  54                                                 bool UnrollLoops,
  55                                                 bool SimplifyLibCalls,
  56                                                 bool HaveExceptions,
  57                                                 Pass *InliningPass);
  58
  59   /// createStandardLTOPasses - Add the standard list of module passes suitable
  60   /// for link time optimization.
  61   ///
  62   /// Internalize - Run the internalize pass.
  63   /// RunInliner - Use a function inlining pass.
  64   /// VerifyEach - Run the verifier after each pass.
  65   static inline void createStandardLTOPasses(PassManagerBase *PM,
  66                                              bool Internalize,
  67                                              bool RunInliner,
  68                                              bool VerifyEach);
  69
  70   // Implementations
  71
  72   static inline void createStandardFunctionPasses(PassManagerBase *PM,
  73                                                   unsigned OptimizationLevel) {
  74     if (OptimizationLevel > 0) {
  75       PM->add(createCFGSimplificationPass());
  76       if (OptimizationLevel == 1)
  77         PM->add(createPromoteMemoryToRegisterPass());
  78       else
  79         PM->add(createScalarReplAggregatesPass());
  80       PM->add(createInstructionCombiningPass());
  81     }
  82   }
  83
  84   /// createStandardModulePasses - Add the standard module passes.  This is
  85   /// expected to be run after the standard function passes.
  86   static inline void createStandardModulePasses(PassManagerBase *PM,
  87                                                 unsigned OptimizationLevel,
  88                                                 bool OptimizeSize,
  89                                                 bool UnitAtATime,
  90                                                 bool UnrollLoops,
  91                                                 bool SimplifyLibCalls,
  92                                                 bool HaveExceptions,
  93                                                 Pass *InliningPass) {
  94     if (OptimizationLevel == 0) {
  95       if (InliningPass)
  96         PM->add(InliningPass);
  97       return;
  98     }
  99
 100     if (UnitAtATime) {
 101       PM->add(createGlobalOptimizerPass());     // Optimize out global vars
 102
 103       PM->add(createIPSCCPPass());              // IP SCCP
 104       PM->add(createDeadArgEliminationPass());  // Dead argument elimination
 105     }
 106     PM->add(createInstructionCombiningPass());  // Clean up after IPCP & DAE
 107     PM->add(createCFGSimplificationPass());     // Clean up after IPCP & DAE
 108
 109     // Start of CallGraph SCC passes.
 110     if (UnitAtATime && HaveExceptions)
 111       PM->add(createPruneEHPass());           // Remove dead EH info
 112     if (InliningPass)
 113       PM->add(InliningPass);
 114     if (UnitAtATime)
 115       PM->add(createFunctionAttrsPass());       // Set readonly/readnone attrs
 116     if (OptimizationLevel > 2)
 117       PM->add(createArgumentPromotionPass());   // Scalarize uninlined fn args
 118
 119     // Start of function pass.
 120
 121     PM->add(createScalarReplAggregatesPass());  // Break up aggregate allocas
 122     if (SimplifyLibCalls)
 123       PM->add(createSimplifyLibCallsPass());    // Library Call Optimizations
 124     PM->add(createInstructionCombiningPass());  // Cleanup for scalarrepl.
 125     PM->add(createJumpThreadingPass());         // Thread jumps.
 126     PM->add(createCFGSimplificationPass());     // Merge & remove BBs
 127     PM->add(createInstructionCombiningPass());  // Combine silly seq's
 128
 129     PM->add(createTailCallEliminationPass());   // Eliminate tail calls
 130     PM->add(createCFGSimplificationPass());     // Merge & remove BBs
 131     PM->add(createReassociatePass());           // Reassociate expressions
 132     // Explicitly schedule this to ensure that it runs before any loop pass.
 133     PM->add(new DominanceFrontier());           // Calculate Dominance Frontiers
 134     PM->add(createLoopRotatePass());            // Rotate Loop
 135     PM->add(createLICMPass());                  // Hoist loop invariants
 136     PM->add(createLoopUnswitchPass(OptimizeSize || OptimizationLevel < 3));
 137     PM->add(createInstructionCombiningPass());
 138     PM->add(createIndVarSimplifyPass());        // Canonicalize indvars
 139     PM->add(createLoopDeletionPass());          // Delete dead loops
 140     if (UnrollLoops)
 141       PM->add(createLoopUnrollPass());          // Unroll small loops
 142     PM->add(createInstructionCombiningPass());  // Clean up after the unroller
 143     if (OptimizationLevel > 1)
 144       PM->add(createGVNPass());                 // Remove redundancies
 145     PM->add(createMemCpyOptPass());             // Remove memcpy / form memset
 146     PM->add(createSCCPPass());                  // Constant prop with SCCP
 147
 148     // Run instcombine after redundancy elimination to exploit opportunities
 149     // opened up by them.
 150     PM->add(createInstructionCombiningPass());
 151     PM->add(createJumpThreadingPass());         // Thread jumps
 152     PM->add(createDeadStoreEliminationPass());  // Delete dead stores
 153     PM->add(createAggressiveDCEPass());         // Delete dead instructions
 154     PM->add(createCFGSimplificationPass());     // Merge & remove BBs
 155
 156     if (UnitAtATime) {
 157       PM->add(createStripDeadPrototypesPass()); // Get rid of dead prototypes
 158       PM->add(createDeadTypeEliminationPass()); // Eliminate dead types
 159
 160       // GlobalOpt already deletes dead functions and globals, at -O3 try a
 161       // late pass of GlobalDCE.  It is capable of deleting dead cycles.
 162       if (OptimizationLevel > 2)
 163         PM->add(createGlobalDCEPass());         // Remove dead fns and globals.
 164
 165       if (OptimizationLevel > 1)
 166         PM->add(createConstantMergePass());       // Merge dup global constants
 167     }
 168   }
 169
 170   static inline void addOnePass(PassManagerBase *PM, Pass *P, bool AndVerify) {
 171     PM->add(P);
 172
 173     if (AndVerify)
 174       PM->add(createVerifierPass());
 175   }
 176
 177   static inline void createStandardLTOPasses(PassManagerBase *PM,
 178                                              bool Internalize,
 179                                              bool RunInliner,
 180                                              bool VerifyEach) {
 181     // Now that composite has been compiled, scan through the module, looking
 182     // for a main function.  If main is defined, mark all other functions
 183     // internal.
 184     if (Internalize)
 185       addOnePass(PM, createInternalizePass(true), VerifyEach);
 186
 187     // Propagate constants at call sites into the functions they call.  This
 188     // opens opportunities for globalopt (and inlining) by substituting function
 189     // pointers passed as arguments to direct uses of functions.
 190     addOnePass(PM, createIPSCCPPass(), VerifyEach);
 191
 192     // Now that we internalized some globals, see if we can hack on them!
 193     addOnePass(PM, createGlobalOptimizerPass(), VerifyEach);
 194
 195     // Linking modules together can lead to duplicated global constants, only
 196     // keep one copy of each constant...
 197     addOnePass(PM, createConstantMergePass(), VerifyEach);
 198
 199     // Remove unused arguments from functions...
 200     addOnePass(PM, createDeadArgEliminationPass(), VerifyEach);
 201
 202     // Reduce the code after globalopt and ipsccp.  Both can open up significant
 203     // simplification opportunities, and both can propagate functions through
 204     // function pointers.  When this happens, we often have to resolve varargs
 205     // calls, etc, so let instcombine do this.
 206     addOnePass(PM, createInstructionCombiningPass(), VerifyEach);
 207
 208     // Inline small functions
 209     if (RunInliner)
 210       addOnePass(PM, createFunctionInliningPass(), VerifyEach);
 211
 212     addOnePass(PM, createPruneEHPass(), VerifyEach);   // Remove dead EH info.
 213     // Optimize globals again if we ran the inliner.
 214     if (RunInliner)
 215       addOnePass(PM, createGlobalOptimizerPass(), VerifyEach);
 216     addOnePass(PM, createGlobalDCEPass(), VerifyEach); // Remove dead functions.
 217
 218     // If we didn't decide to inline a function, check to see if we can
 219     // transform it to pass arguments by value instead of by reference.
 220     addOnePass(PM, createArgumentPromotionPass(), VerifyEach);
 221
 222     // The IPO passes may leave cruft around.  Clean up after them.
 223     addOnePass(PM, createInstructionCombiningPass(), VerifyEach);
 224     addOnePass(PM, createJumpThreadingPass(), VerifyEach);
 225     // Break up allocas
 226     addOnePass(PM, createScalarReplAggregatesPass(), VerifyEach);
 227
 228     // Run a few AA driven optimizations here and now, to cleanup the code.
 229     addOnePass(PM, createFunctionAttrsPass(), VerifyEach); // Add nocapture.
 230     addOnePass(PM, createGlobalsModRefPass(), VerifyEach); // IP alias analysis.
 231
 232     addOnePass(PM, createLICMPass(), VerifyEach);      // Hoist loop invariants.
 233     addOnePass(PM, createGVNPass(), VerifyEach);       // Remove redundancies.
 234     addOnePass(PM, createMemCpyOptPass(), VerifyEach); // Remove dead memcpys.
 235     // Nuke dead stores.
 236     addOnePass(PM, createDeadStoreEliminationPass(), VerifyEach);
 237
 238     // Cleanup and simplify the code after the scalar optimizations.
 239     addOnePass(PM, createInstructionCombiningPass(), VerifyEach);
 240
 241     addOnePass(PM, createJumpThreadingPass(), VerifyEach);
 242
 243     // Delete basic blocks, which optimization passes may have killed.
 244     addOnePass(PM, createCFGSimplificationPass(), VerifyEach);
 245
 246     // Now that we have optimized the program, discard unreachable functions.
 247     addOnePass(PM, createGlobalDCEPass(), VerifyEach);
 248   }
 249 }
 250
 251 #endif