InlineSimple.cpp revision f7477470d37ee2ab9075eaee4745fa084d424ab8 
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  };
53}
54
55char SimpleInliner::ID = 0;
56static RegisterPass<SimpleInliner>
57X("inline", "Function Integration/Inlining");
58
59Pass *llvm::createFunctionInliningPass() { return new SimpleInliner(); }
60
61Pass *llvm::createFunctionInliningPass(int Threshold) {
62  return new SimpleInliner(Threshold);
63}
64
65// doInitialization - Initializes the vector of functions that have been
66// annotated with the noinline attribute.
67bool SimpleInliner::doInitialization(CallGraph &CG) {
68
69  Module &M = CG.getModule();
70
71  for (Module::iterator I = M.begin(), E = M.end();
72       I != E; ++I)
73    if (!I->isDeclaration() && I->hasFnAttr(Attribute::NoInline))
74      NeverInline.insert(I);
75
76  // Get llvm.noinline
77  GlobalVariable *GV = M.getNamedGlobal("llvm.noinline");
78
79  if (GV == 0)
80    return false;
81
82  // Don't crash on invalid code
83  if (!GV->hasDefinitiveInitializer())
84    return false;
85
86  const ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
87
88  if (InitList == 0)
89    return false;
90
91  // Iterate over each element and add to the NeverInline set
92  for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
93
94    // Get Source
95    const Constant *Elt = InitList->getOperand(i);
96
97    if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(Elt))
98      if (CE->getOpcode() == Instruction::BitCast)
99        Elt = CE->getOperand(0);
100
101    // Insert into set of functions to never inline
102    if (const Function *F = dyn_cast<Function>(Elt))
103      NeverInline.insert(F);
104  }
105
106  return false;
107}
108
109