//===-- User.cpp - Implement the User class -------------------------------===//

//

//                     The LLVM Compiler Infrastructure

//

// This file is distributed under the University of Illinois Open Source

// License. See LICENSE.TXT for details.

//

//===----------------------------------------------------------------------===//

#include "llvm/IR/User.h"

#include "llvm/IR/Constant.h"

#include "llvm/IR/GlobalValue.h"

#include "llvm/IR/Operator.h"

namespace llvm {

class BasicBlock;

//===----------------------------------------------------------------------===//

//                                 User Class

//===----------------------------------------------------------------------===//

void User::anchor() {}

void User::replaceUsesOfWith(Value *From, Value *To) {

  if (From == To) 
return0
;   // Duh what?

  assert((!isa<Constant>(this) || isa<GlobalValue>(this)) &&

         "Cannot call User::replaceUsesOfWith on a constant!");

  for (unsigned i = 0, E = getNumOperands(); i != E; 
++i133k
)

    if (getOperand(i) == From) {  // Is This operand is pointing to oldval?

      // The side effects of this setOperand call include linking to

      // "To", adding "this" to the uses list of To, and

      // most importantly, removing "this" from the use list of "From".

      setOperand(i, To); // Fix it now...

    }

}

//===----------------------------------------------------------------------===//

//                         User allocHungoffUses Implementation

//===----------------------------------------------------------------------===//

void User::allocHungoffUses(unsigned N, bool IsPhi) {

  assert(HasHungOffUses && "alloc must have hung off uses");

  static_assert(AlignOf<Use>::Alignment >= AlignOf<Use::UserRef>::Alignment,

                "Alignment is insufficient for 'hung-off-uses' pieces");

  static_assert(AlignOf<Use::UserRef>::Alignment >=

                    AlignOf<BasicBlock *>::Alignment,

                "Alignment is insufficient for 'hung-off-uses' pieces");

  // Allocate the array of Uses, followed by a pointer (with bottom bit set) to

  // the User.

  size_t size = N * sizeof(Use) + sizeof(Use::UserRef);

  if (IsPhi)

    size += N * sizeof(BasicBlock *);

  Use *Begin = static_cast<Use*>(::operator new(size));

  Use *End = Begin + N;

  (void) new(End) Use::UserRef(const_cast<User*>(this), 1);

  setOperandList(Use::initTags(Begin, End));

}

void User::growHungoffUses(unsigned NewNumUses, bool IsPhi) {

  assert(HasHungOffUses && "realloc must have hung off uses");

  unsigned OldNumUses = getNumOperands();

  // We don't support shrinking the number of uses.  We wouldn't have enough

  // space to copy the old uses in to the new space.

  assert(NewNumUses > OldNumUses && "realloc must grow num uses");

  Use *OldOps = getOperandList();

  allocHungoffUses(NewNumUses, IsPhi);

  Use *NewOps = getOperandList();

  // Now copy from the old operands list to the new one.

  std::copy(OldOps, OldOps + OldNumUses, NewOps);

  // If this is a Phi, then we need to copy the BB pointers too.

  if (IsPhi) {

    auto *OldPtr =

        reinterpret_cast<char *>(OldOps + OldNumUses) + sizeof(Use::UserRef);

    auto *NewPtr =

        reinterpret_cast<char *>(NewOps + NewNumUses) + sizeof(Use::UserRef);

    std::copy(OldPtr, OldPtr + (OldNumUses * sizeof(BasicBlock *)), NewPtr);

  }

  Use::zap(OldOps, OldOps + OldNumUses, true);

}

//===----------------------------------------------------------------------===//

//                         User operator new Implementations

//===----------------------------------------------------------------------===//

void *User::operator new(size_t Size, unsigned Us) {

  assert(Us < (1u << NumUserOperandsBits) && "Too many operands");

  void *Storage = ::operator new(Size + sizeof(Use) * Us);

  Use *Start = static_cast<Use*>(Storage);

  Use *End = Start + Us;

  User *Obj = reinterpret_cast<User*>(End);

  Obj->NumUserOperands = Us;

  Obj->HasHungOffUses = false;

  Use::initTags(Start, End);

  return Obj;

}

void *User::operator new(size_t Size) {

  // Allocate space for a single Use*

  void *Storage = ::operator new(Size + sizeof(Use *));

  Use **HungOffOperandList = static_cast<Use **>(Storage);

  User *Obj = reinterpret_cast<User *>(HungOffOperandList + 1);

  Obj->NumUserOperands = 0;

  Obj->HasHungOffUses = true;

  *HungOffOperandList = nullptr;

  return Obj;

}

//===----------------------------------------------------------------------===//

//                         User operator delete Implementation

//===----------------------------------------------------------------------===//

void User::operator delete(void *Usr) {

  // Hung off uses use a single Use* before the User, while other subclasses

  // use a Use[] allocated prior to the user.

  User *Obj = static_cast<User *>(Usr);

  if (Obj->HasHungOffUses) {

    Use **HungOffOperandList = static_cast<Use **>(Usr) - 1;

    // drop the hung off uses.

    Use::zap(*HungOffOperandList, *HungOffOperandList + Obj->NumUserOperands,

             /* Delete */ true);

    ::operator delete(HungOffOperandList);

  } else {

    Use *Storage = static_cast<Use *>(Usr) - Obj->NumUserOperands;

    Use::zap(Storage, Storage + Obj->NumUserOperands,

             /* Delete */ false);

    ::operator delete(Storage);

  }

}

// HLSL Change Starts

void User::operator delete(void *Usr, unsigned NumUserOperands) {

  // Fun fact: during construction Obj->NumUserOperands is overwritten

  Use *Storage = static_cast<Use *>(Usr) - NumUserOperands;

  Use::zap(Storage, Storage + NumUserOperands, /* Delete */ false);

  ::operator delete(Storage);

}

// HLSL Change Ends

//===----------------------------------------------------------------------===//

//                             Operator Class

//===----------------------------------------------------------------------===//

Operator::~Operator() {

  llvm_unreachable("should never destroy an Operator");

}

} // End llvm namespace