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/Target/TargetData.h"
27#include "llvm/ADT/SmallPtrSet.h"
28
29using namespace llvm;
30
31namespace {
32
33  // AlwaysInliner only inlines functions that are mark as "always inline".
34  class AlwaysInliner : public Inliner {
35    // Functions that are never inlined
36    SmallPtrSet<const Function*, 16> NeverInline;
37    InlineCostAnalyzer CA;
38  public:
39    // Use extremely low threshold.
40    AlwaysInliner() : Inliner(ID, -2000000000) {
41      initializeAlwaysInlinerPass(*PassRegistry::getPassRegistry());
42    }
43    static char ID; // Pass identification, replacement for typeid
44    InlineCost getInlineCost(CallSite CS) {
45      return CA.getInlineCost(CS, NeverInline);
46    }
47    float getInlineFudgeFactor(CallSite CS) {
48      return CA.getInlineFudgeFactor(CS);
49    }
50    void resetCachedCostInfo(Function *Caller) {
51      CA.resetCachedCostInfo(Caller);
52    }
53    void growCachedCostInfo(Function* Caller, Function* Callee) {
54      CA.growCachedCostInfo(Caller, Callee);
55    }
56    virtual bool doFinalization(CallGraph &CG) {
57      return removeDeadFunctions(CG, &NeverInline);
58    }
59    virtual bool doInitialization(CallGraph &CG);
60    void releaseMemory() {
61      CA.clear();
62    }
63  };
64}
65
66char AlwaysInliner::ID = 0;
67INITIALIZE_PASS_BEGIN(AlwaysInliner, "always-inline",
68                "Inliner for always_inline functions", false, false)
69INITIALIZE_AG_DEPENDENCY(CallGraph)
70INITIALIZE_PASS_END(AlwaysInliner, "always-inline",
71                "Inliner for always_inline functions", false, false)
72
73Pass *llvm::createAlwaysInlinerPass() { return new AlwaysInliner(); }
74
75// doInitialization - Initializes the vector of functions that have not
76// been annotated with the "always inline" attribute.
77bool AlwaysInliner::doInitialization(CallGraph &CG) {
78  CA.setTargetData(getAnalysisIfAvailable<TargetData>());
79
80  Module &M = CG.getModule();
81
82  for (Module::iterator I = M.begin(), E = M.end();
83       I != E; ++I)
84    if (!I->isDeclaration() && !I->hasFnAttr(Attribute::AlwaysInline))
85      NeverInline.insert(I);
86
87  return false;
88}
89