path: root/lib/VMCore/Constants.cpp

//===-- Constants.cpp - Implement Constant nodes --------------------------===//
// 
//                     The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
// 
//===----------------------------------------------------------------------===//
//
// This file implements the Constant* classes...
//
//===----------------------------------------------------------------------===//

#include "llvm/Constants.h"
#include "ConstantFolding.h"
#include "llvm/DerivedTypes.h"
#include "llvm/GlobalValue.h"
#include "llvm/iMemory.h"
#include "llvm/SymbolTable.h"
#include "llvm/Module.h"
#include "Support/StringExtras.h"
#include <algorithm>
#include <iostream>
using namespace llvm;

ConstantBool *ConstantBool::True  = new ConstantBool(true);
ConstantBool *ConstantBool::False = new ConstantBool(false);


//===----------------------------------------------------------------------===//
//                              Constant Class
//===----------------------------------------------------------------------===//

// Specialize setName to take care of symbol table majik
void Constant::setName(const std::string &Name, SymbolTable *ST) {
  assert(ST && "Type::setName - Must provide symbol table argument!");

  if (Name.size()) ST->insert(Name, this);
}

void Constant::destroyConstantImpl() {
  // When a Constant is destroyed, there may be lingering
  // references to the constant by other constants in the constant pool.  These
  // constants are implicitly dependent on the module that is being deleted,
  // but they don't know that.  Because we only find out when the CPV is
  // deleted, we must now notify all of our users (that should only be
  // Constants) that they are, in fact, invalid now and should be deleted.
  //
  while (!use_empty()) {
    Value *V = use_back();
#ifndef NDEBUG      // Only in -g mode...
    if (!isa<Constant>(V))
      std::cerr << "While deleting: " << *this
                << "\n\nUse still stuck around after Def is destroyed: "
                << *V << "\n\n";
#endif
    assert(isa<Constant>(V) && "References remain to Constant being destroyed");
    Constant *CV = cast<Constant>(V);
    CV->destroyConstant();

    // The constant should remove itself from our use list...
    assert((use_empty() || use_back() != V) && "Constant not removed!");
  }

  // Value has no outstanding references it is safe to delete it now...
  delete this;
}

// Static constructor to create a '0' constant of arbitrary type...
Constant *Constant::getNullValue(const Type *Ty) {
  switch (Ty->getTypeID()) {
  case Type::BoolTyID: {
    static Constant *NullBool = ConstantBool::get(false);
    return NullBool;
  }
  case Type::SByteTyID: {
    static Constant *NullSByte = ConstantSInt::get(Type::SByteTy, 0);
    return NullSByte;
  }
  case Type::UByteTyID: {
    static Constant *NullUByte = ConstantUInt::get(Type::UByteTy, 0);
    return NullUByte;
  }
  case Type::ShortTyID: {
    static Constant *NullShort = ConstantSInt::get(Type::ShortTy, 0);
    return NullShort;
  }
  case Type::UShortTyID: {