InlineSimple.cpp revision 492d06efde44a4e38a6ed321ada4af5a75494df6 
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/Support/Compiler.h"
24#include "llvm/Transforms/IPO.h"
25#include "llvm/Transforms/IPO/InlinerPass.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    SimpleInliner(int Threshold) : Inliner(&ID, Threshold) {}
39    static char ID; // Pass identification, replacement for typeid
40    InlineCost getInlineCost(CallSite CS) {
41      return CA.getInlineCost(CS, NeverInline);
42    }
43    float getInlineFudgeFactor(CallSite CS) {
44      return CA.getInlineFudgeFactor(CS);
45    }
46    void resetCachedCostInfo(Function *Caller) {
47      CA.resetCachedCostInfo(Caller);
48    }
49    virtual bool doInitialization(CallGraph &CG);
50  };
51}
52
53char SimpleInliner::ID = 0;
54static RegisterPass<SimpleInliner>
55X("inline", "Function Integration/Inlining");
56
57Pass *llvm::createFunctionInliningPass() { return new SimpleInliner(); }
58
59Pass *llvm::createFunctionInliningPass(int Threshold) {
60  return new SimpleInliner(Threshold);
61}
62
63// doInitialization - Initializes the vector of functions that have been
64// annotated with the noinline attribute.
65bool SimpleInliner::doInitialization(CallGraph &CG) {
66
67  Module &M = CG.getModule();
68
69  for (Module::iterator I = M.begin(), E = M.end();
70       I != E; ++I)
71    if (!I->isDeclaration() && I->hasFnAttr(Attribute::NoInline))
72      NeverInline.insert(I);
73
74  // Get llvm.noinline
75  GlobalVariable *GV = M.getNamedGlobal("llvm.noinline");
76
77  if (GV == 0)
78    return false;
79
80  // Don't crash on invalid code
81  if (!GV->hasDefinitiveInitializer())
82    return false;
83
84  const ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
85
86  if (InitList == 0)
87    return false;
88
89  // Iterate over each element and add to the NeverInline set
90  for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
91
92    // Get Source
93    const Constant *Elt = InitList->getOperand(i);
94
95    if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(Elt))
96      if (CE->getOpcode() == Instruction::BitCast)
97        Elt = CE->getOperand(0);
98
99    // Insert into set of functions to never inline
100    if (const Function *F = dyn_cast<Function>(Elt))
101      NeverInline.insert(F);
102  }
103
104  return false;
105}
106
107