PseudoSourceValue.cpp revision e264f62ca09a8f65c87a46d562a4d0f9ec5d457e 
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/LLVMContext.h"
18#include "llvm/Support/ErrorHandling.h"
19#include "llvm/Support/ManagedStatic.h"
20#include "llvm/Support/raw_ostream.h"
21#include <map>
22using namespace llvm;
23
24static ManagedStatic<PseudoSourceValue[4]> PSVs;
25
26const PseudoSourceValue *PseudoSourceValue::getStack()
27{ return &(*PSVs)[0]; }
28const PseudoSourceValue *PseudoSourceValue::getGOT()
29{ return &(*PSVs)[1]; }
30const PseudoSourceValue *PseudoSourceValue::getJumpTable()
31{ return &(*PSVs)[2]; }
32const PseudoSourceValue *PseudoSourceValue::getConstantPool()
33{ return &(*PSVs)[3]; }
34
35static const char *const PSVNames[] = {
36  "Stack",
37  "GOT",
38  "JumpTable",
39  "ConstantPool"
40};
41
42// FIXME: THIS IS A HACK!!!!
43// Eventually these should be uniqued on LLVMContext rather than in a managed
44// static.  For now, we can safely use the global context for the time being to
45// squeak by.
46PseudoSourceValue::PseudoSourceValue(enum ValueTy Subclass) :
47  Value(Type::getInt8PtrTy(getGlobalContext()),
48        Subclass) {}
49
50void PseudoSourceValue::printCustom(raw_ostream &O) const {
51  O << PSVNames[this - *PSVs];
52}
53
54static ManagedStatic<std::map<int, const PseudoSourceValue *> > FSValues;
55
56const PseudoSourceValue *PseudoSourceValue::getFixedStack(int FI) {
57  const PseudoSourceValue *&V = (*FSValues)[FI];
58  if (!V)
59    V = new FixedStackPseudoSourceValue(FI);
60  return V;
61}
62
63bool PseudoSourceValue::isConstant(const MachineFrameInfo *) const {
64  if (this == getStack())
65    return false;
66  if (this == getGOT() ||
67      this == getConstantPool() ||
68      this == getJumpTable())
69    return true;
70  llvm_unreachable("Unknown PseudoSourceValue!");
71  return false;
72}
73
74bool PseudoSourceValue::isAliased(const MachineFrameInfo *MFI) const {
75  if (this == getStack() ||
76      this == getGOT() ||
77      this == getConstantPool() ||
78      this == getJumpTable())
79    return false;
80  llvm_unreachable("Unknown PseudoSourceValue!");
81  return true;
82}
83
84bool PseudoSourceValue::mayAlias(const MachineFrameInfo *MFI) const {
85  if (this == getGOT() ||
86      this == getConstantPool() ||
87      this == getJumpTable())
88    return false;
89  return true;
90}
91
92bool FixedStackPseudoSourceValue::isConstant(const MachineFrameInfo *MFI) const{
93  return MFI && MFI->isImmutableObjectIndex(FI);
94}
95
96bool FixedStackPseudoSourceValue::isAliased(const MachineFrameInfo *MFI) const {
97  // Negative frame indices are used for special things that don't
98  // appear in LLVM IR. Non-negative indices may be used for things
99  // like static allocas.
100  if (!MFI)
101    return FI >= 0;
102  // Spill slots should not alias others.
103  return !MFI->isFixedObjectIndex(FI) && !MFI->isSpillSlotObjectIndex(FI);
104}
105
106bool FixedStackPseudoSourceValue::mayAlias(const MachineFrameInfo *MFI) const {
107  if (!MFI)
108    return true;
109  // Spill slots will not alias any LLVM IR value.
110  return !MFI->isSpillSlotObjectIndex(FI);
111}
112
113void FixedStackPseudoSourceValue::printCustom(raw_ostream &OS) const {
114  OS << "FixedStack" << FI;
115}
116