llvm-6502/include/llvm/Value.h
Reid Spencer 53201869cd Document the use of getValueType() more accurately, specifically explain
that the instruction opcode is added to the InstructionVal value and the
consequences of that.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@34937 91177308-0d34-0410-b5e6-96231b3b80d8
2007-03-05 23:06:32 +00:00

258 lines
9.5 KiB
C++

//===-- llvm/Value.h - Definition of the Value class ------------*- C++ -*-===//
//
// 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 declares the Value class.
// This file also defines the Use<> template for users of value.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_VALUE_H
#define LLVM_VALUE_H
#include "llvm/AbstractTypeUser.h"
#include "llvm/Use.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Streams.h"
#include <string>
namespace llvm {
class Constant;
class Argument;
class Instruction;
class BasicBlock;
class GlobalValue;
class Function;
class GlobalVariable;
class InlineAsm;
class ValueSymbolTable;
class TypeSymbolTable;
template<typename ValueTy> class StringMapEntry;
typedef StringMapEntry<Value*> ValueName;
//===----------------------------------------------------------------------===//
// Value Class
//===----------------------------------------------------------------------===//
/// This is a very important LLVM class. It is the base class of all values
/// computed by a program that may be used as operands to other values. Value is
/// the super class of other important classes such as Instruction and Function.
/// All Values have a Type. Type is not a subclass of Value. All types can have
/// a name and they should belong to some Module. Setting the name on the Value
/// automatically update's the module's symbol table.
///
/// Every value has a "use list" that keeps track of which other Values are
/// using this Value.
/// @brief LLVM Value Representation
class Value {
const unsigned short SubclassID; // Subclass identifier (for isa/dyn_cast)
protected:
/// SubclassData - This member is defined by this class, but is not used for
/// anything. Subclasses can use it to hold whatever state they find useful.
/// This field is initialized to zero by the ctor.
unsigned short SubclassData;
private:
PATypeHolder Ty;
Use *UseList;
friend class ValueSymbolTable; // Allow ValueSymbolTable to directly mod Name.
friend class SymbolTable; // Allow SymbolTable to directly poke Name.
ValueName *Name;
void operator=(const Value &); // Do not implement
Value(const Value &); // Do not implement
public:
Value(const Type *Ty, unsigned scid);
virtual ~Value();
/// dump - Support for debugging, callable in GDB: V->dump()
//
virtual void dump() const;
/// print - Implement operator<< on Value...
///
virtual void print(std::ostream &O) const = 0;
void print(std::ostream *O) const { if (O) print(*O); }
/// All values are typed, get the type of this value.
///
inline const Type *getType() const { return Ty; }
// All values can potentially be named...
inline bool hasName() const { return Name != 0; }
std::string getName() const { return getNameStr(); }
std::string getNameStr() const;
ValueName *getValueName() const { return Name; }
void setName(const std::string &name);
void setName(const char *Name, unsigned NameLen);
void setName(const char *Name); // Takes a null-terminated string.
/// takeName - transfer the name from V to this value, setting V's name to
/// empty. It is an error to call V->takeName(V).
void takeName(Value *V);
/// replaceAllUsesWith - Go through the uses list for this definition and make
/// each use point to "V" instead of "this". After this completes, 'this's
/// use list is guaranteed to be empty.
///
void replaceAllUsesWith(Value *V);
// uncheckedReplaceAllUsesWith - Just like replaceAllUsesWith but dangerous.
// Only use when in type resolution situations!
void uncheckedReplaceAllUsesWith(Value *V);
//----------------------------------------------------------------------
// Methods for handling the vector of uses of this Value.
//
typedef value_use_iterator<User> use_iterator;
typedef value_use_iterator<const User> use_const_iterator;
bool use_empty() const { return UseList == 0; }
use_iterator use_begin() { return use_iterator(UseList); }
use_const_iterator use_begin() const { return use_const_iterator(UseList); }
use_iterator use_end() { return use_iterator(0); }
use_const_iterator use_end() const { return use_const_iterator(0); }
User *use_back() { return *use_begin(); }
const User *use_back() const { return *use_begin(); }
/// hasOneUse - Return true if there is exactly one user of this value. This
/// is specialized because it is a common request and does not require
/// traversing the whole use list.
///
bool hasOneUse() const {
use_const_iterator I = use_begin(), E = use_end();
if (I == E) return false;
return ++I == E;
}
/// hasNUses - Return true if this Value has exactly N users.
///
bool hasNUses(unsigned N) const;
/// hasNUsesOrMore - Return true if this value has N users or more. This is
/// logically equivalent to getNumUses() >= N.
///
bool hasNUsesOrMore(unsigned N) const;
/// getNumUses - This method computes the number of uses of this Value. This
/// is a linear time operation. Use hasOneUse, hasNUses, or hasMoreThanNUses
/// to check for specific values.
unsigned getNumUses() const;
/// addUse/killUse - These two methods should only be used by the Use class.
///
void addUse(Use &U) { U.addToList(&UseList); }
/// An enumeration for keeping track of the concrete subclass of Value that
/// is actually instantiated. Values of this enumeration are kept in the
/// Value classes SubclassID field. They are used for concrete type
/// identification.
enum ValueTy {
ArgumentVal, // This is an instance of Argument
BasicBlockVal, // This is an instance of BasicBlock
FunctionVal, // This is an instance of Function
GlobalVariableVal, // This is an instance of GlobalVariable
UndefValueVal, // This is an instance of UndefValue
ConstantExprVal, // This is an instance of ConstantExpr
ConstantAggregateZeroVal, // This is an instance of ConstantAggregateNull
ConstantIntVal, // This is an instance of ConstantInt
ConstantFPVal, // This is an instance of ConstantFP
ConstantArrayVal, // This is an instance of ConstantArray
ConstantStructVal, // This is an instance of ConstantStruct
ConstantVectorVal, // This is an instance of ConstantVector
ConstantPointerNullVal, // This is an instance of ConstantPointerNull
InlineAsmVal, // This is an instance of InlineAsm
InstructionVal, // This is an instance of Instruction
// Markers:
ConstantFirstVal = FunctionVal,
ConstantLastVal = ConstantPointerNullVal
};
/// getValueType - Return an ID for the concrete type of this object. This is
/// used to implement the classof checks. This should not be used for any
/// other purpose, as the values may change as LLVM evolves. Also, note that
/// for instructions, the Instruction's opcode is added to InstructionVal. So
/// this means three things:
/// # there is no value with code InstructionVal (no opcode==0).
/// # there are more possible values for the value type than in ValueTy enum.
/// # the InstructionVal enumerator must be the highest valued enumerator in
/// the ValueTy enum.
unsigned getValueType() const {
return SubclassID;
}
// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const Value *) {
return true; // Values are always values.
}
/// getRawType - This should only be used to implement the vmcore library.
///
const Type *getRawType() const { return Ty.getRawType(); }
};
inline std::ostream &operator<<(std::ostream &OS, const Value &V) {
V.print(OS);
return OS;
}
void Use::init(Value *v, User *user) {
Val = v;
U = user;
if (Val) Val->addUse(*this);
}
Use::~Use() {
if (Val) removeFromList();
}
void Use::set(Value *V) {
if (Val) removeFromList();
Val = V;
if (V) V->addUse(*this);
}
// isa - Provide some specializations of isa so that we don't have to include
// the subtype header files to test to see if the value is a subclass...
//
template <> inline bool isa_impl<Constant, Value>(const Value &Val) {
return Val.getValueType() >= Value::ConstantFirstVal &&
Val.getValueType() <= Value::ConstantLastVal;
}
template <> inline bool isa_impl<Argument, Value>(const Value &Val) {
return Val.getValueType() == Value::ArgumentVal;
}
template <> inline bool isa_impl<InlineAsm, Value>(const Value &Val) {
return Val.getValueType() == Value::InlineAsmVal;
}
template <> inline bool isa_impl<Instruction, Value>(const Value &Val) {
return Val.getValueType() >= Value::InstructionVal;
}
template <> inline bool isa_impl<BasicBlock, Value>(const Value &Val) {
return Val.getValueType() == Value::BasicBlockVal;
}
template <> inline bool isa_impl<Function, Value>(const Value &Val) {
return Val.getValueType() == Value::FunctionVal;
}
template <> inline bool isa_impl<GlobalVariable, Value>(const Value &Val) {
return Val.getValueType() == Value::GlobalVariableVal;
}
template <> inline bool isa_impl<GlobalValue, Value>(const Value &Val) {
return isa<GlobalVariable>(Val) || isa<Function>(Val);
}
} // End llvm namespace
#endif