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ValueMapper.cpp

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00001 //===- ValueMapper.cpp - Interface shared by lib/Transforms/Utils ---------===//
00002 // 
00003 //                     The LLVM Compiler Infrastructure
00004 //
00005 // This file was developed by the LLVM research group and is distributed under
00006 // the University of Illinois Open Source License. See LICENSE.TXT for details.
00007 // 
00008 //===----------------------------------------------------------------------===//
00009 //
00010 // This file defines the MapValue function, which is shared by various parts of
00011 // the lib/Transforms/Utils library.
00012 //
00013 //===----------------------------------------------------------------------===//
00014 
00015 #include "ValueMapper.h"
00016 #include "llvm/Constants.h"
00017 #include "llvm/GlobalValue.h"
00018 #include "llvm/Instruction.h"
00019 #include <iostream>
00020 
00021 using namespace llvm;
00022 
00023 Value *llvm::MapValue(const Value *V, std::map<const Value*, Value*> &VM) {
00024   Value *&VMSlot = VM[V];
00025   if (VMSlot) return VMSlot;      // Does it exist in the map yet?
00026   
00027   // Global values do not need to be seeded into the ValueMap if they are using
00028   // the identity mapping.
00029   if (isa<GlobalValue>(V))
00030     return VMSlot = const_cast<Value*>(V);
00031 
00032   if (Constant *C = const_cast<Constant*>(dyn_cast<Constant>(V))) {
00033     if (isa<ConstantIntegral>(C) || isa<ConstantFP>(C) ||
00034         isa<ConstantPointerNull>(C) || isa<ConstantAggregateZero>(C) ||
00035         isa<UndefValue>(C))
00036       return VMSlot = C;           // Primitive constants map directly
00037     else if (ConstantArray *CA = dyn_cast<ConstantArray>(C)) {
00038       for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i) {
00039         Value *MV = MapValue(CA->getOperand(i), VM);
00040         if (MV != CA->getOperand(i)) {
00041           // This array must contain a reference to a global, make a new array
00042           // and return it.
00043           //
00044           std::vector<Constant*> Values;
00045           Values.reserve(CA->getNumOperands());
00046           for (unsigned j = 0; j != i; ++j)
00047             Values.push_back(CA->getOperand(j));
00048           Values.push_back(cast<Constant>(MV));
00049           for (++i; i != e; ++i)
00050             Values.push_back(cast<Constant>(MapValue(CA->getOperand(i), VM)));
00051           return VMSlot = ConstantArray::get(CA->getType(), Values);
00052         }
00053       }
00054       return VMSlot = C;
00055 
00056     } else if (ConstantStruct *CS = dyn_cast<ConstantStruct>(C)) {
00057       for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) {
00058         Value *MV = MapValue(CS->getOperand(i), VM);
00059         if (MV != CS->getOperand(i)) {
00060           // This struct must contain a reference to a global, make a new struct
00061           // and return it.
00062           //
00063           std::vector<Constant*> Values;
00064           Values.reserve(CS->getNumOperands());
00065           for (unsigned j = 0; j != i; ++j)
00066             Values.push_back(CS->getOperand(j));
00067           Values.push_back(cast<Constant>(MV));
00068           for (++i; i != e; ++i)
00069             Values.push_back(cast<Constant>(MapValue(CS->getOperand(i), VM)));
00070           return VMSlot = ConstantStruct::get(CS->getType(), Values);
00071         }
00072       }
00073       return VMSlot = C;
00074 
00075     } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
00076       if (CE->getOpcode() == Instruction::Cast) {
00077         Constant *MV = cast<Constant>(MapValue(CE->getOperand(0), VM));
00078         return VMSlot = ConstantExpr::getCast(MV, CE->getType());
00079       } else if (CE->getOpcode() == Instruction::GetElementPtr) {
00080         std::vector<Constant*> Idx;
00081         Constant *MV = cast<Constant>(MapValue(CE->getOperand(0), VM));
00082         for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
00083           Idx.push_back(cast<Constant>(MapValue(CE->getOperand(i), VM)));
00084         return VMSlot = ConstantExpr::getGetElementPtr(MV, Idx);
00085       } else if (CE->getOpcode() == Instruction::Select) {
00086         Constant *MV1 = cast<Constant>(MapValue(CE->getOperand(0), VM));
00087         Constant *MV2 = cast<Constant>(MapValue(CE->getOperand(1), VM));
00088         Constant *MV3 = cast<Constant>(MapValue(CE->getOperand(2), VM));
00089         return VMSlot = ConstantExpr::getSelect(MV1, MV2, MV3);
00090       } else {
00091         assert(CE->getNumOperands() == 2 && "Must be binary operator?");
00092         Constant *MV1 = cast<Constant>(MapValue(CE->getOperand(0), VM));
00093         Constant *MV2 = cast<Constant>(MapValue(CE->getOperand(1), VM));
00094         return VMSlot = ConstantExpr::get(CE->getOpcode(), MV1, MV2);
00095       }
00096 
00097     } else {
00098       assert(0 && "Unknown type of constant!");
00099     }
00100   }
00101 
00102   V->dump();
00103   assert(0 && "Unknown value type: why didn't it get resolved?!");
00104   return 0;
00105 }
00106 
00107 /// RemapInstruction - Convert the instruction operands from referencing the
00108 /// current values into those specified by ValueMap.
00109 ///
00110 void llvm::RemapInstruction(Instruction *I,
00111                             std::map<const Value *, Value*> &ValueMap) {
00112   for (unsigned op = 0, E = I->getNumOperands(); op != E; ++op) {
00113     const Value *Op = I->getOperand(op);
00114     Value *V = MapValue(Op, ValueMap);
00115 #ifndef NDEBUG
00116     if (!V) {
00117       std::cerr << "Val = \n" << *Op << "Addr = " << (void*)Op;
00118       std::cerr << "\nInst = " << *I;
00119     }
00120 #endif
00121     assert(V && "Referenced value not in value map!");
00122     I->setOperand(op, V);
00123   }
00124 }