InlineAlways.cpp revision b6c1eccaf3026398325efd7ccb7dbdeae543f281 
1//===- InlineAlways.cpp - Code to inline always_inline functions ----------===//
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 a custom inliner that handles only functions that
11// are marked as "always inline".
12//
13//===----------------------------------------------------------------------===//
14
15#define DEBUG_TYPE "inline"
16#include "llvm/CallingConv.h"
17#include "llvm/Instructions.h"
18#include "llvm/IntrinsicInst.h"
19#include "llvm/Module.h"
20#include "llvm/Type.h"
21#include "llvm/Analysis/CallGraph.h"
22#include "llvm/Analysis/InlineCost.h"
23#include "llvm/Support/CallSite.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  // AlwaysInliner only inlines functions that are mark as "always inline".
33  class AlwaysInliner : public Inliner {
34    // Functions that are never inlined
35    SmallPtrSet<const Function*, 16> NeverInline;
36    InlineCostAnalyzer CA;
37  public:
38    // Use extremely low threshold.
39    AlwaysInliner() : Inliner(&ID, -2000000000) {}
40    static char ID; // Pass identification, replacement for typeid
41    InlineCost getInlineCost(CallSite CS) {
42      return CA.getInlineCost(CS, NeverInline);
43    }
44    float getInlineFudgeFactor(CallSite CS) {
45      return CA.getInlineFudgeFactor(CS);
46    }
47    void resetCachedCostInfo(Function *Caller) {
48      CA.resetCachedCostInfo(Caller);
49    }
50    void growCachedCostInfo(Function* Caller, Function* Callee) {
51      CA.growCachedCostInfo(Caller, Callee);
52    }
53    virtual bool doFinalization(CallGraph &CG) {
54      return removeDeadFunctions(CG, &NeverInline);
55    }
56    virtual bool doInitialization(CallGraph &CG);
57  };
58}
59
60char AlwaysInliner::ID = 0;
61static RegisterPass<AlwaysInliner>
62X("always-inline", "Inliner for always_inline functions");
63
64Pass *llvm::createAlwaysInlinerPass() { return new AlwaysInliner(); }
65
66// doInitialization - Initializes the vector of functions that have not
67// been annotated with the "always inline" attribute.
68bool AlwaysInliner::doInitialization(CallGraph &CG) {
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::AlwaysInline))
74      NeverInline.insert(I);
75
76  return false;
77}
78