PseudoSourceValue.cpp revision f5a86f45e75ec744c203270ffa03659eb0a220c1 
1//===-- llvm/CodeGen/PseudoSourceValue.cpp ----------------------*- C++ -*-===//
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 the PseudoSourceValue class.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/CodeGen/MachineFrameInfo.h"
15#include "llvm/CodeGen/PseudoSourceValue.h"
16#include "llvm/DerivedTypes.h"
17#include "llvm/Support/ErrorHandling.h"
18#include "llvm/Support/ManagedStatic.h"
19#include "llvm/Support/raw_ostream.h"
20#include <map>
21using namespace llvm;
22
23static ManagedStatic<PseudoSourceValue[4]> PSVs;
24
25const PseudoSourceValue *PseudoSourceValue::getStack()
26{ return &(*PSVs)[0]; }
27const PseudoSourceValue *PseudoSourceValue::getGOT()
28{ return &(*PSVs)[1]; }
29const PseudoSourceValue *PseudoSourceValue::getJumpTable()
30{ return &(*PSVs)[2]; }
31const PseudoSourceValue *PseudoSourceValue::getConstantPool()
32{ return &(*PSVs)[3]; }
33
34static const char *const PSVNames[] = {
35  "Stack",
36  "GOT",
37  "JumpTable",
38  "ConstantPool"
39};
40
41// FIXME: THIS IS A HACK!!!!
42// Eventually these should be uniqued on LLVMContext rather than in a managed
43// static.  For now, we can safely use the global context for the time being to
44// squeak by.
45PseudoSourceValue::PseudoSourceValue() :
46  Value(Type::getInt8PtrTy(getGlobalContext()),
47        PseudoSourceValueVal) {}
48
49void PseudoSourceValue::printCustom(raw_ostream &O) const {
50  O << PSVNames[this - *PSVs];
51}
52
53namespace {
54  /// FixedStackPseudoSourceValue - A specialized PseudoSourceValue
55  /// for holding FixedStack values, which must include a frame
56  /// index.
57  class FixedStackPseudoSourceValue : public PseudoSourceValue {
58    const int FI;
59  public:
60    explicit FixedStackPseudoSourceValue(int fi) : FI(fi) {}
61
62    virtual bool isConstant(const MachineFrameInfo *MFI) const;
63
64    virtual bool isAliased(const MachineFrameInfo *MFI) const;
65
66    virtual void printCustom(raw_ostream &OS) const {
67      OS << "FixedStack" << FI;
68    }
69  };
70}
71
72static ManagedStatic<std::map<int, const PseudoSourceValue *> > FSValues;
73
74const PseudoSourceValue *PseudoSourceValue::getFixedStack(int FI) {
75  const PseudoSourceValue *&V = (*FSValues)[FI];
76  if (!V)
77    V = new FixedStackPseudoSourceValue(FI);
78  return V;
79}
80
81bool PseudoSourceValue::isConstant(const MachineFrameInfo *) const {
82  if (this == getStack())
83    return false;
84  if (this == getGOT() ||
85      this == getConstantPool() ||
86      this == getJumpTable())
87    return true;
88  llvm_unreachable("Unknown PseudoSourceValue!");
89  return false;
90}
91
92bool PseudoSourceValue::isAliased(const MachineFrameInfo *MFI) const {
93  if (this == getStack() ||
94      this == getGOT() ||
95      this == getConstantPool() ||
96      this == getJumpTable())
97    return false;
98  llvm_unreachable("Unknown PseudoSourceValue!");
99  return true;
100}
101
102bool FixedStackPseudoSourceValue::isConstant(const MachineFrameInfo *MFI) const{
103  return MFI && MFI->isImmutableObjectIndex(FI);
104}
105
106bool FixedStackPseudoSourceValue::isAliased(const MachineFrameInfo *MFI) const {
107  // Negative frame indices are used for special things that don't
108  // appear in LLVM IR. Non-negative indices may be used for things
109  // like static allocas.
110  if (!MFI)
111    return FI >= 0;
112  // Spill slots should not alias others.
113  return !MFI->isFixedObjectIndex(FI) && !MFI->isSpillSlotObjectIndex(FI);
114}
115