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/Analysis/AssumptionCache.h"
15 #include "llvm/Analysis/CallGraph.h"
16 #include "llvm/Analysis/InlineCost.h"
17 #include "llvm/Analysis/TargetLibraryInfo.h"
18 #include "llvm/Analysis/TargetTransformInfo.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.h"
27 #include "llvm/Transforms/IPO/InlinerPass.h"
28 
29 using namespace llvm;
30 
31 #define DEBUG_TYPE "inline"
32 
33 namespace {
34 
35 /// \brief Actual inliner pass implementation.
36 ///
37 /// The common implementation of the inlining logic is shared between this
38 /// inliner pass and the always inliner pass. The two passes use different cost
39 /// analyses to determine when to inline.
40 class SimpleInliner : public Inliner {
41 
42 public:
43   SimpleInliner() : Inliner(ID) {
44     initializeSimpleInlinerPass(*PassRegistry::getPassRegistry());
45   }
46 
47   SimpleInliner(int Threshold)
48       : Inliner(ID, Threshold, /*InsertLifetime*/ true) {
49     initializeSimpleInlinerPass(*PassRegistry::getPassRegistry());
50   }
51 
52   static char ID; // Pass identification, replacement for typeid
53 
54   InlineCost getInlineCost(CallSite CS) override {
55     Function *Callee = CS.getCalledFunction();
56     TargetTransformInfo &TTI = TTIWP->getTTI(*Callee);
57     return llvm::getInlineCost(CS, getInlineThreshold(CS), TTI, ACT);
58   }
59 
60   bool runOnSCC(CallGraphSCC &SCC) override;
61   void getAnalysisUsage(AnalysisUsage &AU) const override;
62 
63 private:
64   TargetTransformInfoWrapperPass *TTIWP;
65 };
66 
67 static int computeThresholdFromOptLevels(unsigned OptLevel,
68                                          unsigned SizeOptLevel) {
69   if (OptLevel > 2)
70     return 275;
71   if (SizeOptLevel == 1) // -Os
72     return 75;
73   if (SizeOptLevel == 2) // -Oz
74     return 25;
75   return 225;
76 }
77 
78 } // end anonymous namespace
79 
80 char SimpleInliner::ID = 0;
81 INITIALIZE_PASS_BEGIN(SimpleInliner, "inline",
82                 "Function Integration/Inlining", false, false)
83 INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
84 INITIALIZE_PASS_DEPENDENCY(CallGraphWrapperPass)
85 INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)
86 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
87 INITIALIZE_PASS_END(SimpleInliner, "inline",
88                 "Function Integration/Inlining", false, false)
89 
90 Pass *llvm::createFunctionInliningPass() { return new SimpleInliner(); }
91 
92 Pass *llvm::createFunctionInliningPass(int Threshold) {
93   return new SimpleInliner(Threshold);
94 }
95 
96 Pass *llvm::createFunctionInliningPass(unsigned OptLevel,
97                                        unsigned SizeOptLevel) {
98   return new SimpleInliner(
99       computeThresholdFromOptLevels(OptLevel, SizeOptLevel));
100 }
101 
102 bool SimpleInliner::runOnSCC(CallGraphSCC &SCC) {
103   TTIWP = &getAnalysis<TargetTransformInfoWrapperPass>();
104   return Inliner::runOnSCC(SCC);
105 }
106 
107 void SimpleInliner::getAnalysisUsage(AnalysisUsage &AU) const {
108   AU.addRequired<TargetTransformInfoWrapperPass>();
109   Inliner::getAnalysisUsage(AU);
110 }
111