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      1 // llvm/Transforms/IPO/PassManagerBuilder.h - Build Standard Pass -*- 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 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 #ifndef LLVM_TRANSFORMS_IPO_PASSMANAGERBUILDER_H
     16 #define LLVM_TRANSFORMS_IPO_PASSMANAGERBUILDER_H
     17 
     18 #include <vector>
     19 
     20 namespace llvm {
     21 class Pass;
     22 class TargetLibraryInfoImpl;
     23 class TargetMachine;
     24 
     25 // The old pass manager infrastructure is hidden in a legacy namespace now.
     26 namespace legacy {
     27 class FunctionPassManager;
     28 class PassManagerBase;
     29 }
     30 
     31 /// PassManagerBuilder - This class is used to set up a standard optimization
     32 /// sequence for languages like C and C++, allowing some APIs to customize the
     33 /// pass sequence in various ways. A simple example of using it would be:
     34 ///
     35 ///  PassManagerBuilder Builder;
     36 ///  Builder.OptLevel = 2;
     37 ///  Builder.populateFunctionPassManager(FPM);
     38 ///  Builder.populateModulePassManager(MPM);
     39 ///
     40 /// In addition to setting up the basic passes, PassManagerBuilder allows
     41 /// frontends to vend a plugin API, where plugins are allowed to add extensions
     42 /// to the default pass manager.  They do this by specifying where in the pass
     43 /// pipeline they want to be added, along with a callback function that adds
     44 /// the pass(es).  For example, a plugin that wanted to add a loop optimization
     45 /// could do something like this:
     46 ///
     47 /// static void addMyLoopPass(const PMBuilder &Builder, PassManagerBase &PM) {
     48 ///   if (Builder.getOptLevel() > 2 && Builder.getOptSizeLevel() == 0)
     49 ///     PM.add(createMyAwesomePass());
     50 /// }
     51 ///   ...
     52 ///   Builder.addExtension(PassManagerBuilder::EP_LoopOptimizerEnd,
     53 ///                        addMyLoopPass);
     54 ///   ...
     55 class PassManagerBuilder {
     56 public:
     57   /// Extensions are passed the builder itself (so they can see how it is
     58   /// configured) as well as the pass manager to add stuff to.
     59   typedef void (*ExtensionFn)(const PassManagerBuilder &Builder,
     60                               legacy::PassManagerBase &PM);
     61   enum ExtensionPointTy {
     62     /// EP_EarlyAsPossible - This extension point allows adding passes before
     63     /// any other transformations, allowing them to see the code as it is coming
     64     /// out of the frontend.
     65     EP_EarlyAsPossible,
     66 
     67     /// EP_ModuleOptimizerEarly - This extension point allows adding passes
     68     /// just before the main module-level optimization passes.
     69     EP_ModuleOptimizerEarly,
     70 
     71     /// EP_LoopOptimizerEnd - This extension point allows adding loop passes to
     72     /// the end of the loop optimizer.
     73     EP_LoopOptimizerEnd,
     74 
     75     /// EP_ScalarOptimizerLate - This extension point allows adding optimization
     76     /// passes after most of the main optimizations, but before the last
     77     /// cleanup-ish optimizations.
     78     EP_ScalarOptimizerLate,
     79 
     80     /// EP_OptimizerLast -- This extension point allows adding passes that
     81     /// run after everything else.
     82     EP_OptimizerLast,
     83 
     84     /// EP_EnabledOnOptLevel0 - This extension point allows adding passes that
     85     /// should not be disabled by O0 optimization level. The passes will be
     86     /// inserted after the inlining pass.
     87     EP_EnabledOnOptLevel0,
     88 
     89     /// EP_Peephole - This extension point allows adding passes that perform
     90     /// peephole optimizations similar to the instruction combiner. These passes
     91     /// will be inserted after each instance of the instruction combiner pass.
     92     EP_Peephole,
     93   };
     94 
     95   /// The Optimization Level - Specify the basic optimization level.
     96   ///    0 = -O0, 1 = -O1, 2 = -O2, 3 = -O3
     97   unsigned OptLevel;
     98 
     99   /// SizeLevel - How much we're optimizing for size.
    100   ///    0 = none, 1 = -Os, 2 = -Oz
    101   unsigned SizeLevel;
    102 
    103   /// LibraryInfo - Specifies information about the runtime library for the
    104   /// optimizer.  If this is non-null, it is added to both the function and
    105   /// per-module pass pipeline.
    106   TargetLibraryInfoImpl *LibraryInfo;
    107 
    108   /// Inliner - Specifies the inliner to use.  If this is non-null, it is
    109   /// added to the per-module passes.
    110   Pass *Inliner;
    111 
    112   bool DisableTailCalls;
    113   bool DisableUnitAtATime;
    114   bool DisableUnrollLoops;
    115   bool BBVectorize;
    116   bool SLPVectorize;
    117   bool LoopVectorize;
    118   bool RerollLoops;
    119   bool LoadCombine;
    120   bool DisableGVNLoadPRE;
    121   bool VerifyInput;
    122   bool VerifyOutput;
    123   bool MergeFunctions;
    124 
    125 private:
    126   /// ExtensionList - This is list of all of the extensions that are registered.
    127   std::vector<std::pair<ExtensionPointTy, ExtensionFn> > Extensions;
    128 
    129 public:
    130   PassManagerBuilder();
    131   ~PassManagerBuilder();
    132   /// Adds an extension that will be used by all PassManagerBuilder instances.
    133   /// This is intended to be used by plugins, to register a set of
    134   /// optimisations to run automatically.
    135   static void addGlobalExtension(ExtensionPointTy Ty, ExtensionFn Fn);
    136   void addExtension(ExtensionPointTy Ty, ExtensionFn Fn);
    137 
    138 private:
    139   void addExtensionsToPM(ExtensionPointTy ETy,
    140                          legacy::PassManagerBase &PM) const;
    141   void addInitialAliasAnalysisPasses(legacy::PassManagerBase &PM) const;
    142   void addLTOOptimizationPasses(legacy::PassManagerBase &PM);
    143   void addLateLTOOptimizationPasses(legacy::PassManagerBase &PM);
    144 
    145 public:
    146   /// populateFunctionPassManager - This fills in the function pass manager,
    147   /// which is expected to be run on each function immediately as it is
    148   /// generated.  The idea is to reduce the size of the IR in memory.
    149   void populateFunctionPassManager(legacy::FunctionPassManager &FPM);
    150 
    151   /// populateModulePassManager - This sets up the primary pass manager.
    152   void populateModulePassManager(legacy::PassManagerBase &MPM);
    153   void populateLTOPassManager(legacy::PassManagerBase &PM);
    154 };
    155 
    156 /// Registers a function for adding a standard set of passes.  This should be
    157 /// used by optimizer plugins to allow all front ends to transparently use
    158 /// them.  Create a static instance of this class in your plugin, providing a
    159 /// private function that the PassManagerBuilder can use to add your passes.
    160 struct RegisterStandardPasses {
    161   RegisterStandardPasses(PassManagerBuilder::ExtensionPointTy Ty,
    162                          PassManagerBuilder::ExtensionFn Fn) {
    163     PassManagerBuilder::addGlobalExtension(Ty, Fn);
    164   }
    165 };
    166 
    167 } // end namespace llvm
    168 #endif
    169