InlineSimple.cpp revision d6605a8512d567beab56429e70bdc30062556930 
1//===- InlineSimple.cpp - Code to perform simple function inlining --------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file was developed by the LLVM research group and is distributed under
6// the University of Illinois Open Source 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/Support/CallSite.h"
22#include "llvm/Support/Compiler.h"
23#include "llvm/Transforms/IPO.h"
24#include "llvm/Transforms/IPO/InlinerPass.h"
25#include "llvm/Transforms/Utils/InlineCost.h"
26#include "llvm/ADT/SmallPtrSet.h"
27
28using namespace llvm;
29
30namespace {
31
32  class VISIBILITY_HIDDEN 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    static char ID; // Pass identification, replacement for typeid
39    int getInlineCost(CallSite CS) {
40      return CA.getInlineCost(CS, NeverInline);
41    }
42    virtual bool doInitialization(CallGraph &CG);
43  };
44  char SimpleInliner::ID = 0;
45  RegisterPass<SimpleInliner> X("inline", "Function Integration/Inlining");
46}
47
48Pass *llvm::createFunctionInliningPass() { return new SimpleInliner(); }
49
50// doInitialization - Initializes the vector of functions that have been
51// annotated with the noinline attribute.
52bool SimpleInliner::doInitialization(CallGraph &CG) {
53
54  Module &M = CG.getModule();
55
56  // Get llvm.noinline
57  GlobalVariable *GV = M.getNamedGlobal("llvm.noinline");
58
59  if (GV == 0)
60    return false;
61
62  const ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
63
64  if (InitList == 0)
65    return false;
66
67  // Iterate over each element and add to the NeverInline set
68  for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
69
70    // Get Source
71    const Constant *Elt = InitList->getOperand(i);
72
73    if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(Elt))
74      if (CE->getOpcode() == Instruction::BitCast)
75        Elt = CE->getOperand(0);
76
77    // Insert into set of functions to never inline
78    if (const Function *F = dyn_cast<Function>(Elt))
79      NeverInline.insert(F);
80  }
81
82  return false;
83}
84
85