InlineSimple.cpp revision 5580e98eccbc98d875b9b4dca4ba8f6e8faf99a9 
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/ADT/SmallPtrSet.h"
26
27using namespace llvm;
28
29namespace {
30
31  class SimpleInliner : public Inliner {
32    // Functions that are never inlined
33    SmallPtrSet<const Function*, 16> NeverInline;
34    InlineCostAnalyzer CA;
35  public:
36    SimpleInliner() : Inliner(ID) {}
37    SimpleInliner(int Threshold) : Inliner(ID, Threshold) {}
38    static char ID; // Pass identification, replacement for typeid
39    InlineCost getInlineCost(CallSite CS) {
40      return CA.getInlineCost(CS, NeverInline);
41    }
42    float getInlineFudgeFactor(CallSite CS) {
43      return CA.getInlineFudgeFactor(CS);
44    }
45    void resetCachedCostInfo(Function *Caller) {
46      CA.resetCachedCostInfo(Caller);
47    }
48    void growCachedCostInfo(Function* Caller, Function* Callee) {
49      CA.growCachedCostInfo(Caller, Callee);
50    }
51    virtual bool doInitialization(CallGraph &CG);
52    void releaseMemory() {
53      CA.clear();
54    }
55  };
56}
57
58char SimpleInliner::ID = 0;
59INITIALIZE_PASS_BEGIN(SimpleInliner, "inline",
60                "Function Integration/Inlining", false, false)
61INITIALIZE_AG_DEPENDENCY(CallGraph)
62INITIALIZE_PASS_END(SimpleInliner, "inline",
63                "Function Integration/Inlining", false, false)
64
65Pass *llvm::createFunctionInliningPass() { return new SimpleInliner(); }
66
67Pass *llvm::createFunctionInliningPass(int Threshold) {
68  return new SimpleInliner(Threshold);
69}
70
71// doInitialization - Initializes the vector of functions that have been
72// annotated with the noinline attribute.
73bool SimpleInliner::doInitialization(CallGraph &CG) {
74
75  Module &M = CG.getModule();
76
77  for (Module::iterator I = M.begin(), E = M.end();
78       I != E; ++I)
79    if (!I->isDeclaration() && I->hasFnAttr(Attribute::NoInline))
80      NeverInline.insert(I);
81
82  // Get llvm.noinline
83  GlobalVariable *GV = M.getNamedGlobal("llvm.noinline");
84
85  if (GV == 0)
86    return false;
87
88  // Don't crash on invalid code
89  if (!GV->hasDefinitiveInitializer())
90    return false;
91
92  const ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
93
94  if (InitList == 0)
95    return false;
96
97  // Iterate over each element and add to the NeverInline set
98  for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
99
100    // Get Source
101    const Constant *Elt = InitList->getOperand(i);
102
103    if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(Elt))
104      if (CE->getOpcode() == Instruction::BitCast)
105        Elt = CE->getOperand(0);
106
107    // Insert into set of functions to never inline
108    if (const Function *F = dyn_cast<Function>(Elt))
109      NeverInline.insert(F);
110  }
111
112  return false;
113}
114
115