Instructions.cpp

//===-- Instructions.cpp - Implement the LLVM instructions ----------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements all of the non-inline methods for the LLVM instruction
// classes.
//
//===----------------------------------------------------------------------===//

#include "llvm/BasicBlock.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Function.h"
#include "llvm/Instructions.h"
#include "llvm/ParamAttrsList.h"
#include "llvm/Support/CallSite.h"
#include "llvm/Support/ConstantRange.h"
#include "llvm/Support/MathExtras.h"
using namespace llvm;

//===----------------------------------------------------------------------===//
//                            CallSite Class
//===----------------------------------------------------------------------===//

CallSite::CallSite(Instruction *C) {
  assert((isa<CallInst>(C) || isa<InvokeInst>(C)) && "Not a call!");
  I = C;
}
unsigned CallSite::getCallingConv() const {
  if (CallInst *CI = dyn_cast<CallInst>(I))
    return CI->getCallingConv();
  else
    return cast<InvokeInst>(I)->getCallingConv();
}
void CallSite::setCallingConv(unsigned CC) {
  if (CallInst *CI = dyn_cast<CallInst>(I))
    CI->setCallingConv(CC);
  else
    cast<InvokeInst>(I)->setCallingConv(CC);
}
const ParamAttrsList* CallSite::getParamAttrs() const {
  if (CallInst *CI = dyn_cast<CallInst>(I))
    return CI->getParamAttrs();
  else
    return cast<InvokeInst>(I)->getParamAttrs();
}
void CallSite::setParamAttrs(const ParamAttrsList *PAL) {
  if (CallInst *CI = dyn_cast<CallInst>(I))
    CI->setParamAttrs(PAL);
  else
    cast<InvokeInst>(I)->setParamAttrs(PAL);
}
bool CallSite::paramHasAttr(uint16_t i, ParameterAttributes attr) const {
  if (CallInst *CI = dyn_cast<CallInst>(I))
    return CI->paramHasAttr(i, attr);
  else
    return cast<InvokeInst>(I)->paramHasAttr(i, attr);
}
uint16_t CallSite::getParamAlignment(uint16_t i) const {
  if (CallInst *CI = dyn_cast<CallInst>(I))
    return CI->getParamAlignment(i);
  else
    return cast<InvokeInst>(I)->getParamAlignment(i);
}

bool CallSite::doesNotAccessMemory() const {
  if (CallInst *CI = dyn_cast<CallInst>(I))
    return CI->doesNotAccessMemory();
  else
    return cast<InvokeInst>(I)->doesNotAccessMemory();
}
bool CallSite::onlyReadsMemory() const {
  if (CallInst *CI = dyn_cast<CallInst>(I))
    return CI->onlyReadsMemory();
  else
    return cast<InvokeInst>(I)->onlyReadsMemory();
}
bool CallSite::doesNotThrow() const {
  if (CallInst *CI = dyn_cast<CallInst>(I))
    return CI->doesNotThrow();
  else
    return cast<InvokeInst>(I)->doesNotThrow();
}
void CallSite::setDoesNotThrow(bool doesNotThrow) {
  if (CallInst *CI = dyn_cast<CallInst>(I))
    CI->setDoesNotThrow(doesNotThrow);
  else
    cast<InvokeInst>(I)->setDoesNotThrow(doesNotThrow);
}

//===----------------------------------------------------------------------===//
//                            TerminatorInst Class
//===----------------------------------------------------------------------===//

// Out of line virtual method, so the vtable, etc has a home.
TerminatorInst::~TerminatorInst() {
}

// Out of line virtual method, so the vtable, etc has a home.
UnaryInstruction::~UnaryInstruction() {
}


//===----------------------------------------------------------------------===//
//                               PHINode Class
//===----------------------------------------------------------------------===//

PHINode::PHINode(const PHINode &PN)
  : Instruction(PN.getType(), Instruction::PHI,
                new Use[PN.getNumOperands()], PN.getNumOperands()),
    ReservedSpace(PN.getNumOperands()) {
  Use *OL = OperandList;
  for (unsigned i = 0, e = PN.getNumOperands(); i != e; i+=2) {
    OL[i].init(PN.getOperand(i), this);
    OL[i+1].init(PN.getOperand(i+1), this);
  }
}

PHINode::~PHINode() {
  delete [] OperandList;
}

// removeIncomingValue - Remove an incoming value.  This is useful if a
// predecessor basic block is deleted.
Value *PHINode::removeIncomingValue(unsigned Idx, bool DeletePHIIfEmpty) {
  unsigned NumOps = getNumOperands();
  Use *OL = OperandList;
  assert(Idx*2 < NumOps && "BB not in PHI node!");
  Value *Removed = OL[Idx*2];

  // Move everything after this operand down.
  //
  // FIXME: we could just swap with the end of the list, then erase.  However,
  // client might not expect this to happen.  The code as it is thrashes the
  // use/def lists, which is kinda lame.
  for (unsigned i = (Idx+1)*2; i != NumOps; i += 2) {
    OL[i-2] = OL[i];
    OL[i-2+1] = OL[i+1];
  }

  // Nuke the last value.
  OL[NumOps-2].set(0);
  OL[NumOps-2+1].set(0);
  NumOperands = NumOps-2;

  // If the PHI node is dead, because it has zero entries, nuke it now.
  if (NumOps == 2 && DeletePHIIfEmpty) {
    // If anyone is using this PHI, make them use a dummy value instead...
    replaceAllUsesWith(UndefValue::get(getType()));
    eraseFromParent();
  }
  return Removed;
}

/// resizeOperands - resize operands - This adjusts the length of the operands
/// list according to the following behavior:
///   1. If NumOps == 0, grow the operand list in response to a push_back style
///      of operation.  This grows the number of ops by 1.5 times.
///   2. If NumOps > NumOperands, reserve space for NumOps operands.
///   3. If NumOps == NumOperands, trim the reserved space.
///
void PHINode::resizeOperands(unsigned NumOps) {
  if (NumOps == 0) {
    NumOps = (getNumOperands())*3/2;
    if (NumOps < 4) NumOps = 4;      // 4 op PHI nodes are VERY common.
  } else if (NumOps*2 > NumOperands) {
    // No resize needed.
    if (ReservedSpace >= NumOps) return;
  } else if (NumOps == NumOperands) {
    if (ReservedSpace == NumOps) return;
  } else {
    return;
  }

  ReservedSpace = NumOps;
  Use *NewOps = new Use[NumOps];
  Use *OldOps = OperandList;
  for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
      NewOps[i].init(OldOps[i], this);
      OldOps[i].set(0);
  }
  delete [] OldOps;
  OperandList = NewOps;
}

/// hasConstantValue - If the specified PHI node always merges together the same
/// value, return the value, otherwise return null.
///
Value *PHINode::hasConstantValue(bool AllowNonDominatingInstruction) const {
  // If the PHI node only has one incoming value, eliminate the PHI node...
  if (getNumIncomingValues() == 1) {
    if (getIncomingValue(0) != this)   // not  X = phi X
      return getIncomingValue(0);
    else
      return UndefValue::get(getType());  // Self cycle is dead.
  }
      
  // Otherwise if all of the incoming values are the same for the PHI, replace
  // the PHI node with the incoming value.
  //
  Value *InVal = 0;
  bool HasUndefInput = false;
  for (unsigned i = 0, e = getNumIncomingValues(); i != e; ++i)
    if (isa<UndefValue>(getIncomingValue(i))) {
      HasUndefInput = true;
    } else if (getIncomingValue(i) != this) { // Not the PHI node itself...
      if (InVal && getIncomingValue(i) != InVal)
        return 0;  // Not the same, bail out.
      else
        InVal = getIncomingValue(i);
    }
  
  // The only case that could cause InVal to be null is if we have a PHI node
  // that only has entries for itself.  In this case, there is no entry into the
  // loop, so kill the PHI.
  //
  if (InVal == 0) InVal = UndefValue::get(getType());
  
  // If we have a PHI node like phi(X, undef, X), where X is defined by some
  // instruction, we cannot always return X as the result of the PHI node.  Only
  // do this if X is not an instruction (thus it must dominate the PHI block),
  // or if the client is prepared to deal with this possibility.
  if (HasUndefInput && !AllowNonDominatingInstruction)
    if (Instruction *IV = dyn_cast<Instruction>(InVal))
      // If it's in the entry block, it dominates everything.
      if (IV->getParent() != &IV->getParent()->getParent()->getEntryBlock() ||
          isa<InvokeInst>(IV))
        return 0;   // Cannot guarantee that InVal dominates this PHINode.

  // All of the incoming values are the same, return the value now.
  return InVal;
}


//===----------------------------------------------------------------------===//
//                        CallInst Implementation
//===----------------------------------------------------------------------===//

CallInst::~CallInst() {
  delete [] OperandList;
  if (ParamAttrs)
    ParamAttrs->dropRef();
}

void CallInst::init(Value *Func, Value* const *Params, unsigned NumParams) {
  ParamAttrs = 0;
  NumOperands = NumParams+1;
  Use *OL = OperandList = new Use[NumParams+1];
  OL[0].init(Func, this);

  const FunctionType *FTy =
    cast<FunctionType>(cast<PointerType>(Func->getType())->getElementType());
  FTy = FTy;  // silence warning.

  assert((NumParams == FTy->getNumParams() ||
          (FTy->isVarArg() && NumParams > FTy->getNumParams())) &&
         "Calling a function with bad signature!");
  for (unsigned i = 0; i != NumParams; ++i) {
    assert((i >= FTy->getNumParams() || 
            FTy->getParamType(i) == Params[i]->getType()) &&
           "Calling a function with a bad signature!");
    OL[i+1].init(Params[i], this);
  }
}

void CallInst::init(Value *Func, Value *Actual1, Value *Actual2) {
  ParamAttrs = 0;
  NumOperands = 3;
  Use *OL = OperandList = new Use[3];
  OL[0].init(Func, this);
  OL[1].init(Actual1, this);
  OL[2].init(Actual2, this);

  const FunctionType *FTy =
    cast<FunctionType>(cast<PointerType>(Func->getType())->getElementType());
  FTy = FTy;  // silence warning.

  assert((FTy->getNumParams() == 2 ||
          (FTy->isVarArg() && FTy->getNumParams() < 2)) &&
         "Calling a function with bad signature");
  assert((0 >= FTy->getNumParams() || 
          FTy->getParamType(0) == Actual1->getType()) &&
         "Calling a function with a bad signature!");
  assert((1 >= FTy->getNumParams() || 
          FTy->getParamType(1) == Actual2->getType()) &&
         "Calling a function with a bad signature!");
}

void CallInst::init(Value *Func, Value *Actual) {
  ParamAttrs = 0;
  NumOperands = 2;
  Use *OL = OperandList = new Use[2];
  OL[0].init(Func, this);
  OL[1].init(Actual, this);

  const FunctionType *FTy =
    cast<FunctionType>(cast<PointerType>(Func->getType())->getElementType());
  FTy = FTy;  // silence warning.

  assert((FTy->getNumParams() == 1 ||
          (FTy->isVarArg() && FTy->getNumParams() == 0)) &&
         "Calling a function with bad signature");
  assert((0 == FTy->getNumParams() || 
          FTy->getParamType(0) == Actual->getType()) &&
         "Calling a function with a bad signature!");
}

void CallInst::init(Value *Func) {
  ParamAttrs = 0;
  NumOperands = 1;
  Use *OL = OperandList = new Use[1];
  OL[0].init(Func, this);

  const FunctionType *FTy =
    cast<FunctionType>(cast<PointerType>(Func->getType())->getElementType());
  FTy = FTy;  // silence warning.

  assert(FTy->getNumParams() == 0 && "Calling a function with bad signature");
}

CallInst::CallInst(Value *Func, Value* Actual, const std::string &Name,
                   Instruction *InsertBefore)
  : Instruction(cast<FunctionType>(cast<PointerType>(Func->getType())
                                   ->getElementType())->getReturnType(),
                Instruction::Call, 0, 0, InsertBefore) {
  init(Func, Actual);
  setName(Name);
}

CallInst::CallInst(Value *Func, Value* Actual, const std::string &Name,
                   BasicBlock  *InsertAtEnd)
  : Instruction(cast<FunctionType>(cast<PointerType>(Func->getType())
                                   ->getElementType())->getReturnType(),
                Instruction::Call, 0, 0, InsertAtEnd) {
  init(Func, Actual);
  setName(Name);
}
CallInst::CallInst(Value *Func, const std::string &Name,
                   Instruction *InsertBefore)
  : Instruction(cast<FunctionType>(cast<PointerType>(Func->getType())
                                   ->getElementType())->getReturnType(),
                Instruction::Call, 0, 0, InsertBefore) {
  init(Func);
  setName(Name);
}

CallInst::CallInst(Value *Func, const std::string &Name,
                   BasicBlock *InsertAtEnd)
  : Instruction(cast<FunctionType>(cast<PointerType>(Func->getType())
                                   ->getElementType())->getReturnType(),
                Instruction::Call, 0, 0, InsertAtEnd) {
  init(Func);
  setName(Name);
}

CallInst::CallInst(const CallInst &CI)
  : Instruction(CI.getType(), Instruction::Call, new Use[CI.getNumOperands()],
                CI.getNumOperands()),
    ParamAttrs(0) {
  setParamAttrs(CI.getParamAttrs());
  SubclassData = CI.SubclassData;
  Use *OL = OperandList;
  Use *InOL = CI.OperandList;
  for (unsigned i = 0, e = CI.getNumOperands(); i != e; ++i)
    OL[i].init(InOL[i], this);
}

void CallInst::setParamAttrs(const ParamAttrsList *newAttrs) {
  if (ParamAttrs == newAttrs)
    return;

  if (ParamAttrs)
    ParamAttrs->dropRef();

  if (newAttrs)
    newAttrs->addRef();

  ParamAttrs = newAttrs; 
}

bool CallInst::paramHasAttr(uint16_t i, ParameterAttributes attr) const {
  if (ParamAttrs && ParamAttrs->paramHasAttr(i, attr))
    return true;
  if (const Function *F = getCalledFunction())
    return F->paramHasAttr(i, attr);
  return false;
}

uint16_t CallInst::getParamAlignment(uint16_t i) const {
  if (ParamAttrs && ParamAttrs->getParamAlignment(i))
    return ParamAttrs->getParamAlignment(i);
  if (const Function *F = getCalledFunction())
    return F->getParamAlignment(i);
  return 0;
}

/// @brief Determine if the call does not access memory.
bool CallInst::doesNotAccessMemory() const {
  return paramHasAttr(0, ParamAttr::ReadNone);
}

/// @brief Determine if the call does not access or only reads memory.
bool CallInst::onlyReadsMemory() const {
  return doesNotAccessMemory() || paramHasAttr(0, ParamAttr::ReadOnly);
}

/// @brief Determine if the call cannot return.
bool CallInst::doesNotReturn() const {
  return paramHasAttr(0, ParamAttr::NoReturn);
}

/// @brief Determine if the call cannot unwind.
bool CallInst::doesNotThrow() const {
  return paramHasAttr(0, ParamAttr::NoUnwind);
}

/// @brief Determine if the call returns a structure.
bool CallInst::isStructReturn() const {
  // Be friendly and also check the callee.
  return paramHasAttr(1, ParamAttr::StructRet);
}

/// @brief Determine if any call argument is an aggregate passed by value.
bool CallInst::hasByValArgument() const {
  if (ParamAttrs && ParamAttrs->hasAttrSomewhere(ParamAttr::ByVal))
    return true;
  // Be consistent with other methods and check the callee too.
  if (const Function *F = getCalledFunction())
    if (const ParamAttrsList *PAL = F->getParamAttrs())
      return PAL->hasAttrSomewhere(ParamAttr::ByVal);
  return false;
}

void CallInst::setDoesNotThrow(bool doesNotThrow) {
  const ParamAttrsList *PAL = getParamAttrs();
  if (doesNotThrow)
    PAL = ParamAttrsList::includeAttrs(PAL, 0, ParamAttr::NoUnwind);
  else
    PAL = ParamAttrsList::excludeAttrs(PAL, 0, ParamAttr::NoUnwind);
  setParamAttrs(PAL);
}


//===----------------------------------------------------------------------===//
//                        InvokeInst Implementation
//===----------------------------------------------------------------------===//

InvokeInst::~InvokeInst() {
  delete [] OperandList;
  if (ParamAttrs)
    ParamAttrs->dropRef();
}

void InvokeInst::init(Value *Fn, BasicBlock *IfNormal, BasicBlock *IfException,
                      Value* const *Args, unsigned NumArgs) {
  ParamAttrs = 0;
  NumOperands = 3+NumArgs;
  Use *OL = OperandList = new Use[3+NumArgs];
  OL[0].init(Fn, this);
  OL[1].init(IfNormal, this);
  OL[2].init(IfException, this);
  const FunctionType *FTy =
    cast<FunctionType>(cast<PointerType>(Fn->getType())->getElementType());
  FTy = FTy;  // silence warning.

  assert(((NumArgs == FTy->getNumParams()) ||
          (FTy->isVarArg() && NumArgs > FTy->getNumParams())) &&
         "Calling a function with bad signature");

  for (unsigned i = 0, e = NumArgs; i != e; i++) {
    assert((i >= FTy->getNumParams() || 
            FTy->getParamType(i) == Args[i]->getType()) &&
           "Invoking a function with a bad signature!");
    
    OL[i+3].init(Args[i], this);
  }
}

InvokeInst::InvokeInst(const InvokeInst &II)
  : TerminatorInst(II.getType(), Instruction::Invoke,
                   new Use[II.getNumOperands()], II.getNumOperands()),
    ParamAttrs(0) {
  setParamAttrs(II.getParamAttrs());
  SubclassData = II.SubclassData;
  Use *OL = OperandList, *InOL = II.OperandList;
  for (unsigned i = 0, e = II.getNumOperands(); i != e; ++i)
    OL[i].init(InOL[i], this);
}

BasicBlock *InvokeInst::getSuccessorV(unsigned idx) const {
  return getSuccessor(idx);
}
unsigned InvokeInst::getNumSuccessorsV() const {
  return getNumSuccessors();
}
void InvokeInst::setSuccessorV(unsigned idx, BasicBlock *B) {
  return setSuccessor(idx, B);
}

void InvokeInst::setParamAttrs(const ParamAttrsList *newAttrs) {
  if (ParamAttrs == newAttrs)
    return;

  if (ParamAttrs)
    ParamAttrs->dropRef();

  if (newAttrs)
    newAttrs->addRef();

  ParamAttrs = newAttrs; 
}

bool InvokeInst::paramHasAttr(uint16_t i, ParameterAttributes attr) const {
  if (ParamAttrs && ParamAttrs->paramHasAttr(i, attr))
    return true;
  if (const Function *F = getCalledFunction())
    return F->paramHasAttr(i, attr);
  return false;
}

uint16_t InvokeInst::getParamAlignment(uint16_t i) const {
  if (ParamAttrs && ParamAttrs->getParamAlignment(i))
    return ParamAttrs->getParamAlignment(i);
  if (const Function *F = getCalledFunction())
    return F->getParamAlignment(i);
  return 0;
}

/// @brief Determine if the call does not access memory.
bool InvokeInst::doesNotAccessMemory() const {
  return paramHasAttr(0, ParamAttr::ReadNone);
}

/// @brief Determine if the call does not access or only reads memory.
bool InvokeInst::onlyReadsMemory() const {
  return doesNotAccessMemory() || paramHasAttr(0, ParamAttr::ReadOnly);
}

/// @brief Determine if the call cannot return.
bool InvokeInst::doesNotReturn() const {
  return paramHasAttr(0, ParamAttr::NoReturn);
}

/// @brief Determine if the call cannot unwind.
bool InvokeInst::doesNotThrow() const {
  return paramHasAttr(0, ParamAttr::NoUnwind);
}

void InvokeInst::setDoesNotThrow(bool doesNotThrow) {
  const ParamAttrsList *PAL = getParamAttrs();
  if (doesNotThrow)
    PAL = ParamAttrsList::includeAttrs(PAL, 0, ParamAttr::NoUnwind);
  else
    PAL = ParamAttrsList::excludeAttrs(PAL, 0, ParamAttr::NoUnwind);
  setParamAttrs(PAL);
}

/// @brief Determine if the call returns a structure.
bool InvokeInst::isStructReturn() const {
  // Be friendly and also check the callee.
  return paramHasAttr(1, ParamAttr::StructRet);
}


//===----------------------------------------------------------------------===//
//                        ReturnInst Implementation
//===----------------------------------------------------------------------===//

ReturnInst::ReturnInst(const ReturnInst &RI)
  : TerminatorInst(Type::VoidTy, Instruction::Ret,
                   &RetVal, RI.getNumOperands()) {
  unsigned N = RI.getNumOperands();
  if (N == 1) 
    RetVal.init(RI.RetVal, this);
  else if (N) {
    Use *OL = OperandList = new Use[N];
    for (unsigned i = 0; i < N; ++i)
      OL[i].init(RI.getOperand(i), this);
  }
}

ReturnInst::ReturnInst(Value *retVal, Instruction *InsertBefore)
  : TerminatorInst(Type::VoidTy, Instruction::Ret, &RetVal, 0, InsertBefore) {
  if (retVal)
    init(&retVal, 1);
}
ReturnInst::ReturnInst(Value *retVal, BasicBlock *InsertAtEnd)
  : TerminatorInst(Type::VoidTy, Instruction::Ret, &RetVal, 0, InsertAtEnd) {
  if (retVal)
    init(&retVal, 1);
}
ReturnInst::ReturnInst(BasicBlock *InsertAtEnd)
  : TerminatorInst(Type::VoidTy, Instruction::Ret, &RetVal, 0, InsertAtEnd) {
}

ReturnInst::ReturnInst(Value * const* retVals, unsigned N,
                       Instruction *InsertBefore)
  : TerminatorInst(Type::VoidTy, Instruction::Ret, &RetVal, N, InsertBefore) {
  if (N != 0)
    init(retVals, N);
}
ReturnInst::ReturnInst(Value * const* retVals, unsigned N,
                       BasicBlock *InsertAtEnd)
  : TerminatorInst(Type::VoidTy, Instruction::Ret, &RetVal, N, InsertAtEnd) {
  if (N != 0)
    init(retVals, N);
}
ReturnInst::ReturnInst(Value * const* retVals, unsigned N)
  : TerminatorInst(Type::VoidTy, Instruction::Ret, &RetVal, N) {
  if (N != 0)
    init(retVals, N);
}

void ReturnInst::init(Value * const* retVals, unsigned N) {

  assert (N > 0 && "Invalid operands numbers in ReturnInst init");

  NumOperands = N;
  if (NumOperands == 1) {
    Value *V = *retVals;
    if (V->getType() == Type::VoidTy)
      return;
    RetVal.init(V, this);
    return;
  }

  Use *OL = OperandList = new Use[NumOperands];
  for (unsigned i = 0; i < NumOperands; ++i) {
    Value *V = *retVals++;
    assert(!isa<BasicBlock>(V) &&
           "Cannot return basic block.  Probably using the incorrect ctor");
    OL[i].init(V, this);
  }
}

unsigned ReturnInst::getNumSuccessorsV() const {
  return getNumSuccessors();
}

/// Out-of-line ReturnInst method, put here so the C++ compiler can choose to
/// emit the vtable for the class in this translation unit.
void ReturnInst::setSuccessorV(unsigned idx, BasicBlock *NewSucc) {
  assert(0 && "ReturnInst has no successors!");
}

BasicBlock *ReturnInst::getSuccessorV(unsigned idx) const {
  assert(0 && "ReturnInst has no successors!");
  abort();
  return 0;
}

ReturnInst::~ReturnInst() {
  if (NumOperands > 1)
    delete [] OperandList;
}

//===----------------------------------------------------------------------===//
//                        UnwindInst Implementation
//===----------------------------------------------------------------------===//

UnwindInst::UnwindInst(Instruction *InsertBefore)
  : TerminatorInst(Type::VoidTy, Instruction::Unwind, 0, 0, InsertBefore) {
}
UnwindInst::UnwindInst(BasicBlock *InsertAtEnd)
  : TerminatorInst(Type::VoidTy, Instruction::Unwind, 0, 0, InsertAtEnd) {
}


unsigned UnwindInst::getNumSuccessorsV() const {
  return getNumSuccessors();
}

void UnwindInst::setSuccessorV(unsigned idx, BasicBlock *NewSucc) {
  assert(0 && "UnwindInst has no successors!");
}

BasicBlock *UnwindInst::getSuccessorV(unsigned idx) const {
  assert(0 && "UnwindInst has no successors!");
  abort();
  return 0;
}

//===----------------------------------------------------------------------===//
//                      UnreachableInst Implementation
//===----------------------------------------------------------------------===//

UnreachableInst::UnreachableInst(Instruction *InsertBefore)
  : TerminatorInst(Type::VoidTy, Instruction::Unreachable, 0, 0, InsertBefore) {
}
UnreachableInst::UnreachableInst(BasicBlock *InsertAtEnd)
  : TerminatorInst(Type::VoidTy, Instruction::Unreachable, 0, 0, InsertAtEnd) {
}

unsigned UnreachableInst::getNumSuccessorsV() const {
  return getNumSuccessors();
}

void UnreachableInst::setSuccessorV(unsigned idx, BasicBlock *NewSucc) {
  assert(0 && "UnwindInst has no successors!");
}

BasicBlock *UnreachableInst::getSuccessorV(unsigned idx) const {
  assert(0 && "UnwindInst has no successors!");
  abort();
  return 0;
}

//===----------------------------------------------------------------------===//
//                        BranchInst Implementation
//===----------------------------------------------------------------------===//

void BranchInst::AssertOK() {
  if (isConditional())
    assert(getCondition()->getType() == Type::Int1Ty &&
           "May only branch on boolean predicates!");
}

BranchInst::BranchInst(BasicBlock *IfTrue, Instruction *InsertBefore)
  : TerminatorInst(Type::VoidTy, Instruction::Br, Ops, 1, InsertBefore) {
  assert(IfTrue != 0 && "Branch destination may not be null!");
  Ops[0].init(reinterpret_cast<Value*>(IfTrue), this);
}
BranchInst::BranchInst(BasicBlock *IfTrue, BasicBlock *IfFalse, Value *Cond,
                       Instruction *InsertBefore)
: TerminatorInst(Type::VoidTy, Instruction::Br, Ops, 3, InsertBefore) {
  Ops[0].init(reinterpret_cast<Value*>(IfTrue), this);
  Ops[1].init(reinterpret_cast<Value*>(IfFalse), this);
  Ops[2].init(Cond, this);
#ifndef NDEBUG
  AssertOK();
#endif
}

BranchInst::BranchInst(BasicBlock *IfTrue, BasicBlock *InsertAtEnd)
  : TerminatorInst(Type::VoidTy, Instruction::Br, Ops, 1, InsertAtEnd) {
  assert(IfTrue != 0 && "Branch destination may not be null!");
  Ops[0].init(reinterpret_cast<Value*>(IfTrue), this);
}

BranchInst::BranchInst(BasicBlock *IfTrue, BasicBlock *IfFalse, Value *Cond,
           BasicBlock *InsertAtEnd)
  : TerminatorInst(Type::VoidTy, Instruction::Br, Ops, 3, InsertAtEnd) {
  Ops[0].init(reinterpret_cast<Value*>(IfTrue), this);
  Ops[1].init(reinterpret_cast<Value*>(IfFalse), this);
  Ops[2].init(Cond, this);
#ifndef NDEBUG
  AssertOK();
#endif
}


BranchInst::BranchInst(const BranchInst &BI) :
  TerminatorInst(Type::VoidTy, Instruction::Br, Ops, BI.getNumOperands()) {
  OperandList[0].init(BI.getOperand(0), this);
  if (BI.getNumOperands() != 1) {
    assert(BI.getNumOperands() == 3 && "BR can have 1 or 3 operands!");
    OperandList[1].init(BI.getOperand(1), this);
    OperandList[2].init(BI.getOperand(2), this);
  }
}

BasicBlock *BranchInst::getSuccessorV(unsigned idx) const {
  return getSuccessor(idx);
}
unsigned BranchInst::getNumSuccessorsV() const {
  return getNumSuccessors();
}
void BranchInst::setSuccessorV(unsigned idx, BasicBlock *B) {
  setSuccessor(idx, B);
}


//===----------------------------------------------------------------------===//
//                        AllocationInst Implementation
//===----------------------------------------------------------------------===//

static Value *getAISize(Value *Amt) {
  if (!Amt)
    Amt = ConstantInt::get(Type::Int32Ty, 1);
  else {
    assert(!isa<BasicBlock>(Amt) &&
           "Passed basic block into allocation size parameter! Use other ctor");
    assert(Amt->getType() == Type::Int32Ty &&
           "Malloc/Allocation array size is not a 32-bit integer!");
  }
  return Amt;
}

AllocationInst::AllocationInst(const Type *Ty, Value *ArraySize, unsigned iTy,
                               unsigned Align, const std::string &Name,
                               Instruction *InsertBefore)
  : UnaryInstruction(PointerType::getUnqual(Ty), iTy, getAISize(ArraySize),
                     InsertBefore), Alignment(Align) {
  assert((Align & (Align-1)) == 0 && "Alignment is not a power of 2!");
  assert(Ty != Type::VoidTy && "Cannot allocate void!");
  setName(Name);
}

AllocationInst::AllocationInst(const Type *Ty, Value *ArraySize, unsigned iTy,
                               unsigned Align, const std::string &Name,
                               BasicBlock *InsertAtEnd)
  : UnaryInstruction(PointerType::getUnqual(Ty), iTy, getAISize(ArraySize),
                     InsertAtEnd), Alignment(Align) {
  assert((Align & (Align-1)) == 0 && "Alignment is not a power of 2!");
  assert(Ty != Type::VoidTy && "Cannot allocate void!");
  setName(Name);
}

// Out of line virtual method, so the vtable, etc has a home.
AllocationInst::~AllocationInst() {
}

bool AllocationInst::isArrayAllocation() const {
  if (ConstantInt *CI = dyn_cast<ConstantInt>(getOperand(0)))
    return CI->getZExtValue() != 1;
  return true;
}

const Type *AllocationInst::getAllocatedType() const {
  return getType()->getElementType();
}

AllocaInst::AllocaInst(const AllocaInst &AI)
  : AllocationInst(AI.getType()->getElementType(), (Value*)AI.getOperand(0),
                   Instruction::Alloca, AI.getAlignment()) {
}

MallocInst::MallocInst(const MallocInst &MI)
  : AllocationInst(MI.getType()->getElementType(), (Value*)MI.getOperand(0),
                   Instruction::Malloc, MI.getAlignment()) {
}

//===----------------------------------------------------------------------===//
//                             FreeInst Implementation
//===----------------------------------------------------------------------===//

void FreeInst::AssertOK() {
  assert(isa<PointerType>(getOperand(0)->getType()) &&
         "Can not free something of nonpointer type!");
}

FreeInst::FreeInst(Value *Ptr, Instruction *InsertBefore)
  : UnaryInstruction(Type::VoidTy, Free, Ptr, InsertBefore) {
  AssertOK();
}

FreeInst::FreeInst(Value *Ptr, BasicBlock *InsertAtEnd)
  : UnaryInstruction(Type::VoidTy, Free, Ptr, InsertAtEnd) {
  AssertOK();
}


//===----------------------------------------------------------------------===//
//                           LoadInst Implementation
//===----------------------------------------------------------------------===//

void LoadInst::AssertOK() {
  assert(isa<PointerType>(getOperand(0)->getType()) &&
         "Ptr must have pointer type.");
}

LoadInst::LoadInst(Value *Ptr, const std::string &Name, Instruction *InsertBef)
  : UnaryInstruction(cast<PointerType>(Ptr->getType())->getElementType(),
                     Load, Ptr, InsertBef) {
  setVolatile(false);
  setAlignment(0);
  AssertOK();
  setName(Name);
}

LoadInst::LoadInst(Value *Ptr, const std::string &Name, BasicBlock *InsertAE)
  : UnaryInstruction(cast<PointerType>(Ptr->getType())->getElementType(),
                     Load, Ptr, InsertAE) {
  setVolatile(false);
  setAlignment(0);
  AssertOK();
  setName(Name);
}

LoadInst::LoadInst(Value *Ptr, const std::string &Name, bool isVolatile,
                   Instruction *InsertBef)
  : UnaryInstruction(cast<PointerType>(Ptr->getType())->getElementType(),
                     Load, Ptr, InsertBef) {
  setVolatile(isVolatile);
  setAlignment(0);
  AssertOK();
  setName(Name);
}

LoadInst::LoadInst(Value *Ptr, const std::string &Name, bool isVolatile, 
                   unsigned Align, Instruction *InsertBef)
  : UnaryInstruction(cast<PointerType>(Ptr->getType())->getElementType(),
                     Load, Ptr, InsertBef) {
  setVolatile(isVolatile);
  setAlignment(Align);
  AssertOK();
  setName(Name);
}

LoadInst::LoadInst(Value *Ptr, const std::string &Name, bool isVolatile, 
                   unsigned Align, BasicBlock *InsertAE)
  : UnaryInstruction(cast<PointerType>(Ptr->getType())->getElementType(),
                     Load, Ptr, InsertAE) {
  setVolatile(isVolatile);
  setAlignment(Align);
  AssertOK();
  setName(Name);
}

LoadInst::LoadInst(Value *Ptr, const std::string &Name, bool isVolatile,
                   BasicBlock *InsertAE)
  : UnaryInstruction(cast<PointerType>(Ptr->getType())->getElementType(),
                     Load, Ptr, InsertAE) {
  setVolatile(isVolatile);
  setAlignment(0);
  AssertOK();
  setName(Name);
}



LoadInst::LoadInst(Value *Ptr, const char *Name, Instruction *InsertBef)
  : UnaryInstruction(cast<PointerType>(Ptr->getType())->getElementType(),
                     Load, Ptr, InsertBef) {
  setVolatile(false);
  setAlignment(0);
  AssertOK();
  if (Name && Name[0]) setName(Name);
}

LoadInst::LoadInst(Value *Ptr, const char *Name, BasicBlock *InsertAE)
  : UnaryInstruction(cast<PointerType>(Ptr->getType())->getElementType(),
                     Load, Ptr, InsertAE) {
  setVolatile(false);
  setAlignment(0);
  AssertOK();
  if (Name && Name[0]) setName(Name);
}

LoadInst::LoadInst(Value *Ptr, const char *Name, bool isVolatile,
                   Instruction *InsertBef)
: UnaryInstruction(cast<PointerType>(Ptr->getType())->getElementType(),
                   Load, Ptr, InsertBef) {
  setVolatile(isVolatile);
  setAlignment(0);
  AssertOK();
  if (Name && Name[0]) setName(Name);
}

LoadInst::LoadInst(Value *Ptr, const char *Name, bool isVolatile,
                   BasicBlock *InsertAE)
  : UnaryInstruction(cast<PointerType>(Ptr->getType())->getElementType(),
                     Load, Ptr, InsertAE) {
  setVolatile(isVolatile);
  setAlignment(0);
  AssertOK();
  if (Name && Name[0]) setName(Name);
}

void LoadInst::setAlignment(unsigned Align) {
  assert((Align & (Align-1)) == 0 && "Alignment is not a power of 2!");
  SubclassData = (SubclassData & 1) | ((Log2_32(Align)+1)<<1);
}

//===----------------------------------------------------------------------===//
//                           StoreInst Implementation
//===----------------------------------------------------------------------===//

void StoreInst::AssertOK() {
  assert(isa<PointerType>(getOperand(1)->getType()) &&
         "Ptr must have pointer type!");
  assert(getOperand(0)->getType() ==
                 cast<PointerType>(getOperand(1)->getType())->getElementType()
         && "Ptr must be a pointer to Val type!");
}


StoreInst::StoreInst(Value *val, Value *addr, Instruction *InsertBefore)
  : Instruction(Type::VoidTy, Store, Ops, 2, InsertBefore) {
  Ops[0].init(val, this);
  Ops[1].init(addr, this);
  setVolatile(false);
  setAlignment(0);
  AssertOK();
}

StoreInst::StoreInst(Value *val, Value *addr, BasicBlock *InsertAtEnd)
  : Instruction(Type::VoidTy, Store, Ops, 2, InsertAtEnd) {
  Ops[0].init(val, this);
  Ops[1].init(addr, this);
  setVolatile(false);
  setAlignment(0);
  AssertOK();
}