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/BasicBlock.h"
  17 #include "llvm/DerivedTypes.h"  // For getNullValue(Type::Int32Ty)
  18 #include "llvm/Constants.h"
  19 #include "llvm/GlobalValue.h"
  20 #include "llvm/Instruction.h"
  21 #include "llvm/LLVMContext.h"
  22 #include "llvm/Metadata.h"
  23 #include "llvm/ADT/SmallVector.h"
  24 #include "llvm/Support/ErrorHandling.h"
  25 using namespace llvm;
  26
  27 Value *llvm::MapValue(const Value *V, ValueMapTy &VM, LLVMContext &Context) {
  28   Value *&VMSlot = VM[V];
  29   if (VMSlot) return VMSlot;      // Does it exist in the map yet?
  30
  31   // NOTE: VMSlot can be invalidated by any reference to VM, which can grow the
  32   // DenseMap.  This includes any recursive calls to MapValue.
  33
  34   // Global values and metadata do not need to be seeded into the ValueMap if
  35   // they are using the identity mapping.
  36   if (isa<GlobalValue>(V) || isa<InlineAsm>(V) || isa<MetadataBase>(V))
  37     return VMSlot = const_cast<Value*>(V);
  38
  39   if (Constant *C = const_cast<Constant*>(dyn_cast<Constant>(V))) {
  40     if (isa<ConstantInt>(C) || isa<ConstantFP>(C) ||
  41         isa<ConstantPointerNull>(C) || isa<ConstantAggregateZero>(C) ||
  42         isa<UndefValue>(C) || isa<MDString>(C))
  43       return VMSlot = C;           // Primitive constants map directly
  44     else if (ConstantArray *CA = dyn_cast<ConstantArray>(C)) {
  45       for (User::op_iterator b = CA->op_begin(), i = b, e = CA->op_end();
  46            i != e; ++i) {
  47         Value *MV = MapValue(*i, VM, Context);
  48         if (MV != *i) {
  49           // This array must contain a reference to a global, make a new array
  50           // and return it.
  51           //
  52           std::vector<Constant*> Values;
  53           Values.reserve(CA->getNumOperands());
  54           for (User::op_iterator j = b; j != i; ++j)
  55             Values.push_back(cast<Constant>(*j));
  56           Values.push_back(cast<Constant>(MV));
  57           for (++i; i != e; ++i)
  58             Values.push_back(cast<Constant>(MapValue(*i, VM, Context)));
  59           return VM[V] = ConstantArray::get(CA->getType(), Values);
  60         }
  61       }
  62       return VM[V] = C;
  63
  64     } else if (ConstantStruct *CS = dyn_cast<ConstantStruct>(C)) {
  65       for (User::op_iterator b = CS->op_begin(), i = b, e = CS->op_end();
  66            i != e; ++i) {
  67         Value *MV = MapValue(*i, VM, Context);
  68         if (MV != *i) {
  69           // This struct must contain a reference to a global, make a new struct
  70           // and return it.
  71           //
  72           std::vector<Constant*> Values;
  73           Values.reserve(CS->getNumOperands());
  74           for (User::op_iterator j = b; j != i; ++j)
  75             Values.push_back(cast<Constant>(*j));
  76           Values.push_back(cast<Constant>(MV));
  77           for (++i; i != e; ++i)
  78             Values.push_back(cast<Constant>(MapValue(*i, VM, Context)));
  79           return VM[V] = ConstantStruct::get(CS->getType(), Values);
  80         }
  81       }
  82       return VM[V] = C;
  83
  84     } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
  85       std::vector<Constant*> Ops;
  86       for (User::op_iterator i = CE->op_begin(), e = CE->op_end(); i != e; ++i)
  87         Ops.push_back(cast<Constant>(MapValue(*i, VM, Context)));
  88       return VM[V] = CE->getWithOperands(Ops);
  89     } else if (ConstantVector *CP = dyn_cast<ConstantVector>(C)) {
  90       for (User::op_iterator b = CP->op_begin(), i = b, e = CP->op_end();
  91            i != e; ++i) {
  92         Value *MV = MapValue(*i, VM, Context);
  93         if (MV != *i) {
  94           // This vector value must contain a reference to a global, make a new
  95           // vector constant and return it.
  96           //
  97           std::vector<Constant*> Values;
  98           Values.reserve(CP->getNumOperands());
  99           for (User::op_iterator j = b; j != i; ++j)
 100             Values.push_back(cast<Constant>(*j));
 101           Values.push_back(cast<Constant>(MV));
 102           for (++i; i != e; ++i)
 103             Values.push_back(cast<Constant>(MapValue(*i, VM, Context)));
 104           return VM[V] = ConstantVector::get(Values);
 105         }
 106       }
 107       return VM[V] = C;
 108
 109     } else {
 110       llvm_unreachable("Unknown type of constant!");
 111     }
 112   }
 113   return 0;
 114 }
 115
 116 /// RemapInstruction - Convert the instruction operands from referencing the
 117 /// current values into those specified by ValueMap.
 118 ///
 119 void llvm::RemapInstruction(Instruction *I, ValueMapTy &ValueMap) {
 120   for (User::op_iterator op = I->op_begin(), E = I->op_end(); op != E; ++op) {
 121     Value *V = MapValue(*op, ValueMap, I->getParent()->getContext());
 122     assert(V && "Referenced value not in value map!");
 123     *op = V;
 124   }
 125 }