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+//===-- llvm/Value.h - Definition of the Value class ------------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file declares the Value class.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_VALUE_H
+#define LLVM_VALUE_H
+
+#include "llvm/AbstractTypeUser.h"
+#include "llvm/Use.h"
+#include "llvm/Support/Casting.h"
+#include <iosfwd>
+#include <string>
+
+namespace llvm {
+
+class Constant;
+class Argument;
+class Instruction;
+class BasicBlock;
+class GlobalValue;
+class Function;
+class GlobalVariable;
+class GlobalAlias;
+class InlineAsm;
+class ValueSymbolTable;
+class TypeSymbolTable;
+template<typename ValueTy> class StringMapEntry;
+template <typename ValueTy = Value>
+class AssertingVH;
+typedef StringMapEntry<Value*> ValueName;
+class raw_ostream;
+class AssemblyAnnotationWriter;
+class ValueHandleBase;
+
+//===----------------------------------------------------------------------===//
+// 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 updates the module's symbol table.
+///
+/// Every value has a "use list" that keeps track of which other Values are
+/// using this Value. A Value can also have an arbitrary number of ValueHandle
+/// objects that watch it and listen to RAUW and Destroy events see
+/// llvm/Support/ValueHandle.h for details.
+///
+/// @brief LLVM Value Representation
+class Value {
+ const unsigned char SubclassID; // Subclass identifier (for isa/dyn_cast)
+ unsigned char HasValueHandle : 1; // Has a ValueHandle pointing to this?
+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 VTy;
+ Use *UseList;
+
+ friend class ValueSymbolTable; // Allow ValueSymbolTable to directly mod Name.
+ friend class SymbolTable; // Allow SymbolTable to directly poke Name.
+ friend class ValueHandleBase;
+ 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.
+ ///
+ void print(std::ostream &O, AssemblyAnnotationWriter *AAW = 0) const;
+ void print(raw_ostream &O, AssemblyAnnotationWriter *AAW = 0) const;
+
+ /// All values are typed, get the type of this value.
+ ///
+ inline const Type *getType() const { return VTy; }
+
+ // All values can potentially be named...
+ inline bool hasName() const { return Name != 0; }
+ ValueName *getValueName() const { return Name; }
+
+ /// getNameStart - Return a pointer to a null terminated string for this name.
+ /// Note that names can have null characters within the string as well as at
+ /// their end. This always returns a non-null pointer.
+ const char *getNameStart() const;
+ /// getNameEnd - Return a pointer to the end of the name.
+ const char *getNameEnd() const { return getNameStart() + getNameLen(); }
+
+ /// isName - Return true if this value has the name specified by the provided
+ /// nul terminated string.
+ bool isName(const char *N) const;
+
+ /// getNameLen - Return the length of the string, correctly handling nul
+ /// characters embedded into them.
+ unsigned getNameLen() const;
+
+ /// getName()/getNameStr() - Return the name of the specified value,
+ /// *constructing a string* to hold it. Because these are guaranteed to
+ /// construct a string, they are very expensive and should be avoided.
+ std::string getName() const { return getNameStr(); }
+ std::string getNameStr() const;
+
+
+ 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 chain 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;
+
+ bool isUsedInBasicBlock(const BasicBlock *BB) 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 - This method 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
+ GlobalAliasVal, // This is an instance of GlobalAlias
+ 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
+ MDStringVal, // This is an instance of MDString
+ MDNodeVal, // This is an instance of MDNode
+ InlineAsmVal, // This is an instance of InlineAsm
+ PseudoSourceValueVal, // This is an instance of PseudoSourceValue
+ InstructionVal, // This is an instance of Instruction
+
+ // Markers:
+ ConstantFirstVal = FunctionVal,
+ ConstantLastVal = MDNodeVal
+ };
+
+ /// getValueID - 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 getValueID() 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 VTy.getRawType(); }
+
+ /// stripPointerCasts - This method strips off any unneeded pointer
+ /// casts from the specified value, returning the original uncasted value.
+ /// Note that the returned value has pointer type if the specified value does.
+ Value *stripPointerCasts();
+ const Value *stripPointerCasts() const {
+ return const_cast<Value*>(this)->stripPointerCasts();
+ }
+
+ /// getUnderlyingObject - This method strips off any GEP address adjustments
+ /// and pointer casts from the specified value, returning the original object
+ /// being addressed. Note that the returned value has pointer type if the
+ /// specified value does.
+ Value *getUnderlyingObject();
+ const Value *getUnderlyingObject() const {
+ return const_cast<Value*>(this)->getUnderlyingObject();
+ }
+
+ /// DoPHITranslation - If this value is a PHI node with CurBB as its parent,
+ /// return the value in the PHI node corresponding to PredBB. If not, return
+ /// ourself. This is useful if you want to know the value something has in a
+ /// predecessor block.
+ Value *DoPHITranslation(const BasicBlock *CurBB, const BasicBlock *PredBB);
+
+ const Value *DoPHITranslation(const BasicBlock *CurBB,
+ const BasicBlock *PredBB) const{
+ return const_cast<Value*>(this)->DoPHITranslation(CurBB, PredBB);
+ }
+};
+
+inline std::ostream &operator<<(std::ostream &OS, const Value &V) {
+ V.print(OS);
+ return OS;
+}
+inline raw_ostream &operator<<(raw_ostream &OS, const Value &V) {
+ V.print(OS);
+ return OS;
+}
+
+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.getValueID() >= Value::ConstantFirstVal &&
+ Val.getValueID() <= Value::ConstantLastVal;
+}
+template <> inline bool isa_impl<Argument, Value>(const Value &Val) {
+ return Val.getValueID() == Value::ArgumentVal;
+}
+template <> inline bool isa_impl<InlineAsm, Value>(const Value &Val) {
+ return Val.getValueID() == Value::InlineAsmVal;
+}
+template <> inline bool isa_impl<Instruction, Value>(const Value &Val) {
+ return Val.getValueID() >= Value::InstructionVal;
+}
+template <> inline bool isa_impl<BasicBlock, Value>(const Value &Val) {
+ return Val.getValueID() == Value::BasicBlockVal;
+}
+template <> inline bool isa_impl<Function, Value>(const Value &Val) {
+ return Val.getValueID() == Value::FunctionVal;
+}
+template <> inline bool isa_impl<GlobalVariable, Value>(const Value &Val) {
+ return Val.getValueID() == Value::GlobalVariableVal;
+}
+template <> inline bool isa_impl<GlobalAlias, Value>(const Value &Val) {
+ return Val.getValueID() == Value::GlobalAliasVal;
+}
+template <> inline bool isa_impl<GlobalValue, Value>(const Value &Val) {
+ return isa<GlobalVariable>(Val) || isa<Function>(Val) ||
+ isa<GlobalAlias>(Val);
+}
+
+
+// Value* is only 4-byte aligned.
+template<>
+class PointerLikeTypeTraits<Value*> {
+ typedef Value* PT;
+public:
+ static inline void *getAsVoidPointer(PT P) { return P; }
+ static inline PT getFromVoidPointer(void *P) {
+ return static_cast<PT>(P);
+ }
+ enum { NumLowBitsAvailable = 2 };
+};
+
+} // End llvm namespace
+
+#endif
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