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#define DEBUG_TYPE "inline"
15#include "llvm/CallingConv.h"
16#include "llvm/Instructions.h"
17#include "llvm/IntrinsicInst.h"
18#include "llvm/Module.h"
19#include "llvm/Type.h"
20#include "llvm/Analysis/CallGraph.h"
21#include "llvm/Analysis/InlineCost.h"
22#include "llvm/Support/CallSite.h"
23#include "llvm/Transforms/IPO.h"
24#include "llvm/Transforms/IPO/InlinerPass.h"
25#include "llvm/Target/TargetData.h"
26#include "llvm/ADT/SmallPtrSet.h"
27
28using namespace llvm;
29
30namespace {
31
32  class SimpleInliner : public Inliner {
33    // Functions that are never inlined
34    SmallPtrSet<const Function*, 16> NeverInline;
35    InlineCostAnalyzer CA;
36  public:
37    SimpleInliner() : Inliner(ID) {
38      initializeSimpleInlinerPass(*PassRegistry::getPassRegistry());
39    }
40    SimpleInliner(int Threshold) : Inliner(ID, Threshold) {
41      initializeSimpleInlinerPass(*PassRegistry::getPassRegistry());
42    }
43    static char ID; // Pass identification, replacement for typeid
44    InlineCost getInlineCost(CallSite CS) {
45      return CA.getInlineCost(CS, NeverInline);
46    }
47    float getInlineFudgeFactor(CallSite CS) {
48      return CA.getInlineFudgeFactor(CS);
49    }
50    void resetCachedCostInfo(Function *Caller) {
51      CA.resetCachedCostInfo(Caller);
52    }
53    void growCachedCostInfo(Function* Caller, Function* Callee) {
54      CA.growCachedCostInfo(Caller, Callee);
55    }
56    virtual bool doInitialization(CallGraph &CG);
57    void releaseMemory() {
58      CA.clear();
59    }
60  };
61}
62
63char SimpleInliner::ID = 0;
64INITIALIZE_PASS_BEGIN(SimpleInliner, "inline",
65                "Function Integration/Inlining", false, false)
66INITIALIZE_AG_DEPENDENCY(CallGraph)
67INITIALIZE_PASS_END(SimpleInliner, "inline",
68                "Function Integration/Inlining", false, false)
69
70Pass *llvm::createFunctionInliningPass() { return new SimpleInliner(); }
71
72Pass *llvm::createFunctionInliningPass(int Threshold) {
73  return new SimpleInliner(Threshold);
74}
75
76// doInitialization - Initializes the vector of functions that have been
77// annotated with the noinline attribute.
78bool SimpleInliner::doInitialization(CallGraph &CG) {
79  CA.setTargetData(getAnalysisIfAvailable<TargetData>());
80
81  Module &M = CG.getModule();
82
83  for (Module::iterator I = M.begin(), E = M.end();
84       I != E; ++I)
85    if (!I->isDeclaration() && I->hasFnAttr(Attribute::NoInline))
86      NeverInline.insert(I);
87
88  // Get llvm.noinline
89  GlobalVariable *GV = M.getNamedGlobal("llvm.noinline");
90
91  if (GV == 0)
92    return false;
93
94  // Don't crash on invalid code
95  if (!GV->hasDefinitiveInitializer())
96    return false;
97
98  const ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
99
100  if (InitList == 0)
101    return false;
102
103  // Iterate over each element and add to the NeverInline set
104  for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
105
106    // Get Source
107    const Constant *Elt = InitList->getOperand(i);
108
109    if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(Elt))
110      if (CE->getOpcode() == Instruction::BitCast)
111        Elt = CE->getOperand(0);
112
113    // Insert into set of functions to never inline
114    if (const Function *F = dyn_cast<Function>(Elt))
115      NeverInline.insert(F);
116  }
117
118  return false;
119}
120
121