lib/CodeGen/PseudoSourceValue.cpp

   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 "llvm/Support/Mutex.h"
  22 #include <map>
  23 using namespace llvm;
  24
  25 namespace {
  26 struct PSVGlobalsTy {
  27   // PseudoSourceValues are immutable so don't need locking.
  28   const PseudoSourceValue PSVs[4];
  29   sys::Mutex Lock;  // Guards FSValues, but not the values inside it.
  30   std::map<int, const PseudoSourceValue *> FSValues;
  31
  32   PSVGlobalsTy() : PSVs() {}
  33   ~PSVGlobalsTy() {
  34     for (std::map<int, const PseudoSourceValue *>::iterator
  35            I = FSValues.begin(), E = FSValues.end(); I != E; ++I) {
  36       delete I->second;
  37     }
  38   }
  39 };
  40
  41 static ManagedStatic<PSVGlobalsTy> PSVGlobals;
  42
  43 }  // anonymous namespace
  44
  45 const PseudoSourceValue *PseudoSourceValue::getStack()
  46 { return &PSVGlobals->PSVs[0]; }
  47 const PseudoSourceValue *PseudoSourceValue::getGOT()
  48 { return &PSVGlobals->PSVs[1]; }
  49 const PseudoSourceValue *PseudoSourceValue::getJumpTable()
  50 { return &PSVGlobals->PSVs[2]; }
  51 const PseudoSourceValue *PseudoSourceValue::getConstantPool()
  52 { return &PSVGlobals->PSVs[3]; }
  53
  54 static const char *const PSVNames[] = {
  55   "Stack",
  56   "GOT",
  57   "JumpTable",
  58   "ConstantPool"
  59 };
  60
  61 // FIXME: THIS IS A HACK!!!!
  62 // Eventually these should be uniqued on LLVMContext rather than in a managed
  63 // static.  For now, we can safely use the global context for the time being to
  64 // squeak by.
  65 PseudoSourceValue::PseudoSourceValue(enum ValueTy Subclass) :
  66   Value(Type::getInt8PtrTy(getGlobalContext()),
  67         Subclass) {}
  68
  69 void PseudoSourceValue::printCustom(raw_ostream &O) const {
  70   O << PSVNames[this - PSVGlobals->PSVs];
  71 }
  72
  73 const PseudoSourceValue *PseudoSourceValue::getFixedStack(int FI) {
  74   PSVGlobalsTy &PG = *PSVGlobals;
  75   sys::ScopedLock locked(PG.Lock);
  76   const PseudoSourceValue *&V = PG.FSValues[FI];
  77   if (!V)
  78     V = new FixedStackPseudoSourceValue(FI);
  79   return V;
  80 }
  81
  82 bool PseudoSourceValue::isConstant(const MachineFrameInfo *) const {
  83   if (this == getStack())
  84     return false;
  85   if (this == getGOT() ||
  86       this == getConstantPool() ||
  87       this == getJumpTable())
  88     return true;
  89   llvm_unreachable("Unknown PseudoSourceValue!");
  90   return false;
  91 }
  92
  93 bool PseudoSourceValue::isAliased(const MachineFrameInfo *MFI) const {
  94   if (this == getStack() ||
  95       this == getGOT() ||
  96       this == getConstantPool() ||
  97       this == getJumpTable())
  98     return false;
  99   llvm_unreachable("Unknown PseudoSourceValue!");
 100   return true;
 101 }
 102
 103 bool PseudoSourceValue::mayAlias(const MachineFrameInfo *MFI) const {
 104   if (this == getGOT() ||
 105       this == getConstantPool() ||
 106       this == getJumpTable())
 107     return false;
 108   return true;
 109 }
 110
 111 bool FixedStackPseudoSourceValue::isConstant(const MachineFrameInfo *MFI) const{
 112   return MFI && MFI->isImmutableObjectIndex(FI);
 113 }
 114
 115 bool FixedStackPseudoSourceValue::isAliased(const MachineFrameInfo *MFI) const {
 116   // Negative frame indices are used for special things that don't
 117   // appear in LLVM IR. Non-negative indices may be used for things
 118   // like static allocas.
 119   if (!MFI)
 120     return FI >= 0;
 121   // Spill slots should not alias others.
 122   return !MFI->isFixedObjectIndex(FI) && !MFI->isSpillSlotObjectIndex(FI);
 123 }
 124
 125 bool FixedStackPseudoSourceValue::mayAlias(const MachineFrameInfo *MFI) const {
 126   if (!MFI)
 127     return true;
 128   // Spill slots will not alias any LLVM IR value.
 129   return !MFI->isSpillSlotObjectIndex(FI);
 130 }
 131
 132 void FixedStackPseudoSourceValue::printCustom(raw_ostream &OS) const {
 133   OS << "FixedStack" << FI;
 134 }