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