InlineSimple.cpp revision b5a158bab81b0b3f15d409fc433e706f8e885375 
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    virtual bool doInitialization(CallGraph &CG);
49  };
50}
51
52char SimpleInliner::ID = 0;
53static RegisterPass<SimpleInliner>
54X("inline", "Function Integration/Inlining");
55
56Pass *llvm::createFunctionInliningPass() { return new SimpleInliner(); }
57
58Pass *llvm::createFunctionInliningPass(int Threshold) {
59  return new SimpleInliner(Threshold);
60}
61
62// doInitialization - Initializes the vector of functions that have been
63// annotated with the noinline attribute.
64bool SimpleInliner::doInitialization(CallGraph &CG) {
65
66  Module &M = CG.getModule();
67
68  for (Module::iterator I = M.begin(), E = M.end();
69       I != E; ++I)
70    if (!I->isDeclaration() && I->hasFnAttr(Attribute::NoInline))
71      NeverInline.insert(I);
72
73  // Get llvm.noinline
74  GlobalVariable *GV = M.getNamedGlobal("llvm.noinline");
75
76  if (GV == 0)
77    return false;
78
79  // Don't crash on invalid code
80  if (!GV->hasDefinitiveInitializer())
81    return false;
82
83  const ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
84
85  if (InitList == 0)
86    return false;
87
88  // Iterate over each element and add to the NeverInline set
89  for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
90
91    // Get Source
92    const Constant *Elt = InitList->getOperand(i);
93
94    if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(Elt))
95      if (CE->getOpcode() == Instruction::BitCast)
96        Elt = CE->getOperand(0);
97
98    // Insert into set of functions to never inline
99    if (const Function *F = dyn_cast<Function>(Elt))
100      NeverInline.insert(F);
101  }
102
103  return false;
104}
105
106