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1 //===- InlineSimple.cpp - Code to perform simple function inlining --------===//
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 implements bottom-up inlining of functions into callees.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/Transforms/IPO.h"
15 #include "llvm/Analysis/AssumptionCache.h"
16 #include "llvm/Analysis/CallGraph.h"
17 #include "llvm/Analysis/InlineCost.h"
18 #include "llvm/Analysis/TargetLibraryInfo.h"
19 #include "llvm/IR/CallSite.h"
20 #include "llvm/IR/CallingConv.h"
21 #include "llvm/IR/DataLayout.h"
22 #include "llvm/IR/Instructions.h"
23 #include "llvm/IR/IntrinsicInst.h"
24 #include "llvm/IR/Module.h"
25 #include "llvm/IR/Type.h"
26 #include "llvm/Transforms/IPO/InlinerPass.h"
27 
28 using namespace llvm;
29 
30 #define DEBUG_TYPE "inline"
31 
32 namespace {
33 
34 /// \brief Actual inliner pass implementation.
35 ///
36 /// The common implementation of the inlining logic is shared between this
37 /// inliner pass and the always inliner pass. The two passes use different cost
38 /// analyses to determine when to inline.
39 class SimpleInliner : public Inliner {
40   InlineCostAnalysis *ICA;
41 
42 public:
SimpleInliner()43   SimpleInliner() : Inliner(ID), ICA(nullptr) {
44     initializeSimpleInlinerPass(*PassRegistry::getPassRegistry());
45   }
46 
SimpleInliner(int Threshold)47   SimpleInliner(int Threshold)
48       : Inliner(ID, Threshold, /*InsertLifetime*/ true), ICA(nullptr) {
49     initializeSimpleInlinerPass(*PassRegistry::getPassRegistry());
50   }
51 
52   static char ID; // Pass identification, replacement for typeid
53 
getInlineCost(CallSite CS)54   InlineCost getInlineCost(CallSite CS) override {
55     return ICA->getInlineCost(CS, getInlineThreshold(CS));
56   }
57 
58   bool runOnSCC(CallGraphSCC &SCC) override;
59   void getAnalysisUsage(AnalysisUsage &AU) const override;
60 };
61 
computeThresholdFromOptLevels(unsigned OptLevel,unsigned SizeOptLevel)62 static int computeThresholdFromOptLevels(unsigned OptLevel,
63                                          unsigned SizeOptLevel) {
64   if (OptLevel > 2)
65     return 275;
66   if (SizeOptLevel == 1) // -Os
67     return 75;
68   if (SizeOptLevel == 2) // -Oz
69     return 25;
70   return 225;
71 }
72 
73 } // end anonymous namespace
74 
75 char SimpleInliner::ID = 0;
76 INITIALIZE_PASS_BEGIN(SimpleInliner, "inline",
77                 "Function Integration/Inlining", false, false)
INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)78 INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
79 INITIALIZE_PASS_DEPENDENCY(CallGraphWrapperPass)
80 INITIALIZE_PASS_DEPENDENCY(InlineCostAnalysis)
81 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
82 INITIALIZE_PASS_END(SimpleInliner, "inline",
83                 "Function Integration/Inlining", false, false)
84 
85 Pass *llvm::createFunctionInliningPass() { return new SimpleInliner(); }
86 
createFunctionInliningPass(int Threshold)87 Pass *llvm::createFunctionInliningPass(int Threshold) {
88   return new SimpleInliner(Threshold);
89 }
90 
createFunctionInliningPass(unsigned OptLevel,unsigned SizeOptLevel)91 Pass *llvm::createFunctionInliningPass(unsigned OptLevel,
92                                        unsigned SizeOptLevel) {
93   return new SimpleInliner(
94       computeThresholdFromOptLevels(OptLevel, SizeOptLevel));
95 }
96 
runOnSCC(CallGraphSCC & SCC)97 bool SimpleInliner::runOnSCC(CallGraphSCC &SCC) {
98   ICA = &getAnalysis<InlineCostAnalysis>();
99   return Inliner::runOnSCC(SCC);
100 }
101 
getAnalysisUsage(AnalysisUsage & AU) const102 void SimpleInliner::getAnalysisUsage(AnalysisUsage &AU) const {
103   AU.addRequired<InlineCostAnalysis>();
104   Inliner::getAnalysisUsage(AU);
105 }
106