LLVM  mainline
InlineSimple.cpp
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00001 //===- InlineSimple.cpp - Code to perform simple function inlining --------===//
00002 //
00003 //                     The LLVM Compiler Infrastructure
00004 //
00005 // This file is distributed under the University of Illinois Open Source
00006 // License. See LICENSE.TXT for details.
00007 //
00008 //===----------------------------------------------------------------------===//
00009 //
00010 // This file implements bottom-up inlining of functions into callees.
00011 //
00012 //===----------------------------------------------------------------------===//
00013 
00014 #include "llvm/Transforms/IPO.h"
00015 #include "llvm/Analysis/AliasAnalysis.h"
00016 #include "llvm/Analysis/AssumptionCache.h"
00017 #include "llvm/Analysis/CallGraph.h"
00018 #include "llvm/Analysis/InlineCost.h"
00019 #include "llvm/IR/CallSite.h"
00020 #include "llvm/IR/CallingConv.h"
00021 #include "llvm/IR/DataLayout.h"
00022 #include "llvm/IR/Instructions.h"
00023 #include "llvm/IR/IntrinsicInst.h"
00024 #include "llvm/IR/Module.h"
00025 #include "llvm/IR/Type.h"
00026 #include "llvm/Transforms/IPO/InlinerPass.h"
00027 
00028 using namespace llvm;
00029 
00030 #define DEBUG_TYPE "inline"
00031 
00032 namespace {
00033 
00034 /// \brief Actual inliner pass implementation.
00035 ///
00036 /// The common implementation of the inlining logic is shared between this
00037 /// inliner pass and the always inliner pass. The two passes use different cost
00038 /// analyses to determine when to inline.
00039 class SimpleInliner : public Inliner {
00040   InlineCostAnalysis *ICA;
00041 
00042 public:
00043   SimpleInliner() : Inliner(ID), ICA(nullptr) {
00044     initializeSimpleInlinerPass(*PassRegistry::getPassRegistry());
00045   }
00046 
00047   SimpleInliner(int Threshold)
00048       : Inliner(ID, Threshold, /*InsertLifetime*/ true), ICA(nullptr) {
00049     initializeSimpleInlinerPass(*PassRegistry::getPassRegistry());
00050   }
00051 
00052   static char ID; // Pass identification, replacement for typeid
00053 
00054   InlineCost getInlineCost(CallSite CS) override {
00055     return ICA->getInlineCost(CS, getInlineThreshold(CS));
00056   }
00057 
00058   bool runOnSCC(CallGraphSCC &SCC) override;
00059   void getAnalysisUsage(AnalysisUsage &AU) const override;
00060 };
00061 
00062 static int computeThresholdFromOptLevels(unsigned OptLevel,
00063                                          unsigned SizeOptLevel) {
00064   if (OptLevel > 2)
00065     return 275;
00066   if (SizeOptLevel == 1) // -Os
00067     return 75;
00068   if (SizeOptLevel == 2) // -Oz
00069     return 25;
00070   return 225;
00071 }
00072 
00073 } // end anonymous namespace
00074 
00075 char SimpleInliner::ID = 0;
00076 INITIALIZE_PASS_BEGIN(SimpleInliner, "inline",
00077                 "Function Integration/Inlining", false, false)
00078 INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
00079 INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
00080 INITIALIZE_PASS_DEPENDENCY(CallGraphWrapperPass)
00081 INITIALIZE_PASS_DEPENDENCY(InlineCostAnalysis)
00082 INITIALIZE_PASS_END(SimpleInliner, "inline",
00083                 "Function Integration/Inlining", false, false)
00084 
00085 Pass *llvm::createFunctionInliningPass() { return new SimpleInliner(); }
00086 
00087 Pass *llvm::createFunctionInliningPass(int Threshold) {
00088   return new SimpleInliner(Threshold);
00089 }
00090 
00091 Pass *llvm::createFunctionInliningPass(unsigned OptLevel,
00092                                        unsigned SizeOptLevel) {
00093   return new SimpleInliner(
00094       computeThresholdFromOptLevels(OptLevel, SizeOptLevel));
00095 }
00096 
00097 bool SimpleInliner::runOnSCC(CallGraphSCC &SCC) {
00098   ICA = &getAnalysis<InlineCostAnalysis>();
00099   return Inliner::runOnSCC(SCC);
00100 }
00101 
00102 void SimpleInliner::getAnalysisUsage(AnalysisUsage &AU) const {
00103   AU.addRequired<InlineCostAnalysis>();
00104   Inliner::getAnalysisUsage(AU);
00105 }