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   /// createStandardModulePasses - Add the standard module passes.  This is
  84   /// expected to be run after the standard function passes.
  85   static inline void createStandardModulePasses(PassManager *PM,
  86                                                 unsigned OptimizationLevel,
  87                                                 bool OptimizeSize,
  88                                                 bool UnitAtATime,
  89                                                 bool UnrollLoops,
  90                                                 bool SimplifyLibCalls,
  91                                                 bool HaveExceptions,
  92                                                 Pass *InliningPass) {
  93     if (OptimizationLevel == 0) {
  94       if (InliningPass)
  95         PM->add(InliningPass);
  96       return;
  97     }
  98
  99     if (UnitAtATime) {
 100       PM->add(createGlobalOptimizerPass());     // Optimize out global vars
 101
 102       PM->add(createIPSCCPPass());              // IP SCCP
 103       PM->add(createDeadArgEliminationPass());  // Dead argument elimination
 104     }
 105     PM->add(createInstructionCombiningPass());  // Clean up after IPCP & DAE
 106     PM->add(createCFGSimplificationPass());     // Clean up after IPCP & DAE
 107
 108     // Start of CallGraph SCC passes.
 109     if (UnitAtATime && HaveExceptions)
 110       PM->add(createPruneEHPass());           // Remove dead EH info
 111     if (InliningPass)
 112       PM->add(InliningPass);
 113     if (UnitAtATime)
 114       PM->add(createFunctionAttrsPass());       // Set readonly/readnone attrs
 115     if (OptimizationLevel > 2)
 116       PM->add(createArgumentPromotionPass());   // Scalarize uninlined fn args
 117
 118     // Start of function pass.
 119
 120     PM->add(createScalarReplAggregatesPass());  // Break up aggregate allocas
 121     if (SimplifyLibCalls)
 122       PM->add(createSimplifyLibCallsPass());    // Library Call Optimizations
 123     PM->add(createInstructionCombiningPass());  // Cleanup for scalarrepl.
 124     PM->add(createJumpThreadingPass());         // Thread jumps.
 125     PM->add(createCFGSimplificationPass());     // Merge & remove BBs
 126     PM->add(createInstructionCombiningPass());  // Combine silly seq's
 127
 128     PM->add(createTailCallEliminationPass());   // Eliminate tail calls
 129     PM->add(createCFGSimplificationPass());     // Merge & remove BBs
 130     PM->add(createReassociatePass());           // Reassociate expressions
 131     PM->add(createLoopRotatePass());            // Rotate Loop
 132     PM->add(createLICMPass());                  // Hoist loop invariants
 133     PM->add(createLoopUnswitchPass(OptimizeSize || OptimizationLevel < 3));
 134     PM->add(createInstructionCombiningPass());
 135     PM->add(createIndVarSimplifyPass());        // Canonicalize indvars
 136     PM->add(createLoopDeletionPass());          // Delete dead loops
 137     if (UnrollLoops)
 138       PM->add(createLoopUnrollPass());          // Unroll small loops
 139     PM->add(createInstructionCombiningPass());  // Clean up after the unroller
 140     if (OptimizationLevel > 1)
 141       PM->add(createGVNPass());                 // Remove redundancies
 142     PM->add(createMemCpyOptPass());             // Remove memcpy / form memset
 143     PM->add(createSCCPPass());                  // Constant prop with SCCP
 144
 145     // Run instcombine after redundancy elimination to exploit opportunities
 146     // opened up by them.
 147     PM->add(createInstructionCombiningPass());
 148     PM->add(createJumpThreadingPass());         // Thread jumps
 149     PM->add(createDeadStoreEliminationPass());  // Delete dead stores
 150     PM->add(createAggressiveDCEPass());         // Delete dead instructions
 151     PM->add(createCFGSimplificationPass());     // Merge & remove BBs
 152
 153     if (UnitAtATime) {
 154       PM->add(createStripDeadPrototypesPass()); // Get rid of dead prototypes
 155       PM->add(createDeadTypeEliminationPass()); // Eliminate dead types
 156
 157       // GlobalOpt already deletes dead functions and globals, at -O3 try a
 158       // late pass of GlobalDCE.  It is capable of deleting dead cycles.
 159       if (OptimizationLevel > 2)
 160         PM->add(createGlobalDCEPass());         // Remove dead fns and globals.
 161
 162       if (OptimizationLevel > 1)
 163         PM->add(createConstantMergePass());       // Merge dup global constants
 164     }
 165   }
 166
 167   static inline void addOnePass(PassManager *PM, Pass *P, bool AndVerify) {
 168     PM->add(P);
 169
 170     if (AndVerify)
 171       PM->add(createVerifierPass());
 172   }
 173
 174   static inline void createStandardLTOPasses(PassManager *PM,
 175                                              bool Internalize,
 176                                              bool RunInliner,
 177                                              bool VerifyEach) {
 178     // Now that composite has been compiled, scan through the module, looking
 179     // for a main function.  If main is defined, mark all other functions
 180     // internal.
 181     if (Internalize)
 182       addOnePass(PM, createInternalizePass(true), VerifyEach);
 183
 184     // Propagate constants at call sites into the functions they call.  This
 185     // opens opportunities for globalopt (and inlining) by substituting function
 186     // pointers passed as arguments to direct uses of functions.
 187     addOnePass(PM, createIPSCCPPass(), VerifyEach);
 188
 189     // Now that we internalized some globals, see if we can hack on them!
 190     addOnePass(PM, createGlobalOptimizerPass(), VerifyEach);
 191
 192     // Linking modules together can lead to duplicated global constants, only
 193     // keep one copy of each constant...
 194     addOnePass(PM, createConstantMergePass(), VerifyEach);
 195
 196     // Remove unused arguments from functions...
 197     addOnePass(PM, createDeadArgEliminationPass(), VerifyEach);
 198
 199     // Reduce the code after globalopt and ipsccp.  Both can open up significant
 200     // simplification opportunities, and both can propagate functions through
 201     // function pointers.  When this happens, we often have to resolve varargs
 202     // calls, etc, so let instcombine do this.
 203     addOnePass(PM, createInstructionCombiningPass(), VerifyEach);
 204
 205     // Inline small functions
 206     if (RunInliner)
 207       addOnePass(PM, createFunctionInliningPass(), VerifyEach);
 208
 209     addOnePass(PM, createPruneEHPass(), VerifyEach);   // Remove dead EH info.
 210     // Optimize globals again if we ran the inliner.
 211     if (RunInliner)
 212       addOnePass(PM, createGlobalOptimizerPass(), VerifyEach);
 213     addOnePass(PM, createGlobalDCEPass(), VerifyEach); // Remove dead functions.
 214
 215     // If we didn't decide to inline a function, check to see if we can
 216     // transform it to pass arguments by value instead of by reference.
 217     addOnePass(PM, createArgumentPromotionPass(), VerifyEach);
 218
 219     // The IPO passes may leave cruft around.  Clean up after them.
 220     addOnePass(PM, createInstructionCombiningPass(), VerifyEach);
 221     addOnePass(PM, createJumpThreadingPass(), VerifyEach);
 222     // Break up allocas
 223     addOnePass(PM, createScalarReplAggregatesPass(), VerifyEach);
 224
 225     // Run a few AA driven optimizations here and now, to cleanup the code.
 226     addOnePass(PM, createFunctionAttrsPass(), VerifyEach); // Add nocapture.
 227     addOnePass(PM, createGlobalsModRefPass(), VerifyEach); // IP alias analysis.
 228
 229     addOnePass(PM, createLICMPass(), VerifyEach);      // Hoist loop invariants.
 230     addOnePass(PM, createGVNPass(), VerifyEach);       // Remove redundancies.
 231     addOnePass(PM, createMemCpyOptPass(), VerifyEach); // Remove dead memcpys.
 232     // Nuke dead stores.
 233     addOnePass(PM, createDeadStoreEliminationPass(), VerifyEach);
 234
 235     // Cleanup and simplify the code after the scalar optimizations.
 236     addOnePass(PM, createInstructionCombiningPass(), VerifyEach);
 237
 238     addOnePass(PM, createJumpThreadingPass(), VerifyEach);
 239
 240     // Delete basic blocks, which optimization passes may have killed.
 241     addOnePass(PM, createCFGSimplificationPass(), VerifyEach);
 242
 243     // Now that we have optimized the program, discard unreachable functions.
 244     addOnePass(PM, createGlobalDCEPass(), VerifyEach);
 245   }
 246 }
 247
 248 #endif