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llvm-mirror/include/llvm/User.h
2011-07-18 04:54:35 +00:00

176 lines
6.0 KiB
C++

//===-- llvm/User.h - User class definition ---------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This class defines the interface that one who 'use's a Value must implement.
// Each instance of the Value class keeps track of what User's have handles
// to it.
//
// * Instructions are the largest class of User's.
// * Constants may be users of other constants (think arrays and stuff)
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_USER_H
#define LLVM_USER_H
#include "llvm/Value.h"
namespace llvm {
/// OperandTraits - Compile-time customization of
/// operand-related allocators and accessors
/// for use of the User class
template <class>
struct OperandTraits;
class User : public Value {
User(const User &); // Do not implement
void *operator new(size_t); // Do not implement
template <unsigned>
friend struct HungoffOperandTraits;
protected:
/// OperandList - This is a pointer to the array of Uses for this User.
/// For nodes of fixed arity (e.g. a binary operator) this array will live
/// prefixed to some derived class instance. For nodes of resizable variable
/// arity (e.g. PHINodes, SwitchInst etc.), this memory will be dynamically
/// allocated and should be destroyed by the classes' virtual dtor.
Use *OperandList;
/// NumOperands - The number of values used by this User.
///
unsigned NumOperands;
void *operator new(size_t s, unsigned Us);
User(Type *ty, unsigned vty, Use *OpList, unsigned NumOps)
: Value(ty, vty), OperandList(OpList), NumOperands(NumOps) {}
Use *allocHungoffUses(unsigned) const;
void dropHungoffUses() {
Use::zap(OperandList, OperandList + NumOperands, true);
OperandList = 0;
// Reset NumOperands so User::operator delete() does the right thing.
NumOperands = 0;
}
public:
~User() {
Use::zap(OperandList, OperandList + NumOperands);
}
/// operator delete - free memory allocated for User and Use objects
void operator delete(void *Usr);
/// placement delete - required by std, but never called.
void operator delete(void*, unsigned) {
assert(0 && "Constructor throws?");
}
/// placement delete - required by std, but never called.
void operator delete(void*, unsigned, bool) {
assert(0 && "Constructor throws?");
}
protected:
template <int Idx, typename U> static Use &OpFrom(const U *that) {
return Idx < 0
? OperandTraits<U>::op_end(const_cast<U*>(that))[Idx]
: OperandTraits<U>::op_begin(const_cast<U*>(that))[Idx];
}
template <int Idx> Use &Op() {
return OpFrom<Idx>(this);
}
template <int Idx> const Use &Op() const {
return OpFrom<Idx>(this);
}
public:
Value *getOperand(unsigned i) const {
assert(i < NumOperands && "getOperand() out of range!");
return OperandList[i];
}
void setOperand(unsigned i, Value *Val) {
assert(i < NumOperands && "setOperand() out of range!");
assert((!isa<Constant>((const Value*)this) ||
isa<GlobalValue>((const Value*)this)) &&
"Cannot mutate a constant with setOperand!");
OperandList[i] = Val;
}
const Use &getOperandUse(unsigned i) const {
assert(i < NumOperands && "getOperandUse() out of range!");
return OperandList[i];
}
Use &getOperandUse(unsigned i) {
assert(i < NumOperands && "getOperandUse() out of range!");
return OperandList[i];
}
unsigned getNumOperands() const { return NumOperands; }
// ---------------------------------------------------------------------------
// Operand Iterator interface...
//
typedef Use* op_iterator;
typedef const Use* const_op_iterator;
inline op_iterator op_begin() { return OperandList; }
inline const_op_iterator op_begin() const { return OperandList; }
inline op_iterator op_end() { return OperandList+NumOperands; }
inline const_op_iterator op_end() const { return OperandList+NumOperands; }
// dropAllReferences() - This function is in charge of "letting go" of all
// objects that this User refers to. This allows one to
// 'delete' a whole class at a time, even though there may be circular
// references... First all references are dropped, and all use counts go to
// zero. Then everything is deleted for real. Note that no operations are
// valid on an object that has "dropped all references", except operator
// delete.
//
void dropAllReferences() {
for (op_iterator i = op_begin(), e = op_end(); i != e; ++i)
i->set(0);
}
/// replaceUsesOfWith - Replaces all references to the "From" definition with
/// references to the "To" definition.
///
void replaceUsesOfWith(Value *From, Value *To);
// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const User *) { return true; }
static inline bool classof(const Value *V) {
return isa<Instruction>(V) || isa<Constant>(V);
}
};
template<> struct simplify_type<User::op_iterator> {
typedef Value* SimpleType;
static SimpleType getSimplifiedValue(const User::op_iterator &Val) {
return static_cast<SimpleType>(Val->get());
}
};
template<> struct simplify_type<const User::op_iterator>
: public simplify_type<User::op_iterator> {};
template<> struct simplify_type<User::const_op_iterator> {
typedef Value* SimpleType;
static SimpleType getSimplifiedValue(const User::const_op_iterator &Val) {
return static_cast<SimpleType>(Val->get());
}
};
template<> struct simplify_type<const User::const_op_iterator>
: public simplify_type<User::const_op_iterator> {};
// value_use_iterator::getOperandNo - Requires the definition of the User class.
template<typename UserTy>
unsigned value_use_iterator<UserTy>::getOperandNo() const {
return U - U->getUser()->op_begin();
}
} // End llvm namespace
#endif