lib/Transforms/Utils/ValueMapper.cpp

   1 //===- ValueMapper.cpp - Interface shared by lib/Transforms/Utils ---------===//
   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 defines the MapValue function, which is shared by various parts of
  11 // the lib/Transforms/Utils library.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "llvm/Transforms/Utils/ValueMapper.h"
  16 #include "llvm/Constants.h"
  17 #include "llvm/GlobalValue.h"
  18 #include "llvm/Instruction.h"
  19 using namespace llvm;
  20
  21 Value *llvm::MapValue(const Value *V, ValueMapTy &VM) {
  22   Value *&VMSlot = VM[V];
  23   if (VMSlot) return VMSlot;      // Does it exist in the map yet?
  24
  25   // NOTE: VMSlot can be invalidated by any reference to VM, which can grow the
  26   // DenseMap.  This includes any recursive calls to MapValue.
  27
  28   // Global values do not need to be seeded into the ValueMap if they are using
  29   // the identity mapping.
  30   if (isa<GlobalValue>(V) || isa<InlineAsm>(V))
  31     return VMSlot = const_cast<Value*>(V);
  32
  33   if (Constant *C = const_cast<Constant*>(dyn_cast<Constant>(V))) {
  34     if (isa<ConstantInt>(C) || isa<ConstantFP>(C) ||
  35         isa<ConstantPointerNull>(C) || isa<ConstantAggregateZero>(C) ||
  36         isa<UndefValue>(C))
  37       return VMSlot = C;           // Primitive constants map directly
  38     else if (ConstantArray *CA = dyn_cast<ConstantArray>(C)) {
  39       for (User::op_iterator b = CA->op_begin(), i = b, e = CA->op_end();
  40            i != e; ++i) {
  41         Value *MV = MapValue(*i, VM);
  42         if (MV != *i) {
  43           // This array must contain a reference to a global, make a new array
  44           // and return it.
  45           //
  46           std::vector<Constant*> Values;
  47           Values.reserve(CA->getNumOperands());
  48           for (User::op_iterator j = b; j != i; ++j)
  49             Values.push_back(cast<Constant>(*j));
  50           Values.push_back(cast<Constant>(MV));
  51           for (++i; i != e; ++i)
  52             Values.push_back(cast<Constant>(MapValue(*i, VM)));
  53           return VM[V] = ConstantArray::get(CA->getType(), Values);
  54         }
  55       }
  56       return VM[V] = C;
  57
  58     } else if (ConstantStruct *CS = dyn_cast<ConstantStruct>(C)) {
  59       for (User::op_iterator b = CS->op_begin(), i = b, e = CS->op_end();
  60            i != e; ++i) {
  61         Value *MV = MapValue(*i, VM);
  62         if (MV != *i) {
  63           // This struct must contain a reference to a global, make a new struct
  64           // and return it.
  65           //
  66           std::vector<Constant*> Values;
  67           Values.reserve(CS->getNumOperands());
  68           for (User::op_iterator j = b; j != i; ++j)
  69             Values.push_back(cast<Constant>(*j));
  70           Values.push_back(cast<Constant>(MV));
  71           for (++i; i != e; ++i)
  72             Values.push_back(cast<Constant>(MapValue(*i, VM)));
  73           return VM[V] = ConstantStruct::get(CS->getType(), Values);
  74         }
  75       }
  76       return VM[V] = C;
  77
  78     } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
  79       std::vector<Constant*> Ops;
  80       for (User::op_iterator i = CE->op_begin(), e = CE->op_end(); i != e; ++i)
  81         Ops.push_back(cast<Constant>(MapValue(*i, VM)));
  82       return VM[V] = CE->getWithOperands(Ops);
  83     } else if (ConstantVector *CP = dyn_cast<ConstantVector>(C)) {
  84       for (User::op_iterator b = CP->op_begin(), i = b, e = CP->op_end();
  85            i != e; ++i) {
  86         Value *MV = MapValue(*i, VM);
  87         if (MV != *i) {
  88           // This vector value must contain a reference to a global, make a new
  89           // vector constant and return it.
  90           //
  91           std::vector<Constant*> Values;
  92           Values.reserve(CP->getNumOperands());
  93           for (User::op_iterator j = b; j != i; ++j)
  94             Values.push_back(cast<Constant>(*j));
  95           Values.push_back(cast<Constant>(MV));
  96           for (++i; i != e; ++i)
  97             Values.push_back(cast<Constant>(MapValue(*i, VM)));
  98           return VM[V] = ConstantVector::get(Values);
  99         }
 100       }
 101       return VM[V] = C;
 102
 103     } else {
 104       assert(0 && "Unknown type of constant!");
 105     }
 106   }
 107
 108   return 0;
 109 }
 110
 111 /// RemapInstruction - Convert the instruction operands from referencing the
 112 /// current values into those specified by ValueMap.
 113 ///
 114 void llvm::RemapInstruction(Instruction *I, ValueMapTy &ValueMap) {
 115   for (User::op_iterator op = I->op_begin(), E = I->op_end(); op != E; ++op) {
 116     Value *V = MapValue(*op, ValueMap);
 117     assert(V && "Referenced value not in value map!");
 118     *op = V;
 119   }
 120 }