//
// 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 is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
#include "llvm/User.h"
namespace llvm {
+ template<typename T> class SmallVectorImpl;
+ class LLVMContext;
+ /// If object contains references to other objects, then relocations are
+ /// usually required for emission of such object (especially in PIC mode). One
+ /// usually distinguishes local and global relocations. Local relocations are
+ /// made wrt objects in the same module and these objects have local (internal
+ /// or private) linkage. Global relocations are made wrt externally visible
+ /// objects. In most cases local relocations can be resolved via so-called
+ /// 'pre-link' technique.
+ namespace Reloc {
+ const unsigned None = 0;
+ const unsigned Local = 1 << 0; ///< Local relocations are required
+ const unsigned Global = 1 << 1; ///< Global relocations are required
+ const unsigned LocalOrGlobal = Local | Global;
+ }
+
+/// This is an important base class in LLVM. It provides the common facilities
+/// of all constant values in an LLVM program. A constant is a value that is
+/// immutable at runtime. Functions are constants because their address is
+/// immutable. Same with global variables.
+///
+/// All constants share the capabilities provided in this class. All constants
+/// can have a null value. They can have an operand list. Constants can be
+/// simple (integer and floating point values), complex (arrays and structures),
+/// or expression based (computations yielding a constant value composed of
+/// only certain operators and other constant values).
+///
+/// Note that Constants are immutable (once created they never change)
+/// and are fully shared by structural equivalence. This means that two
+/// structurally equivalent constants will always have the same address.
+/// Constants are created on demand as needed and never deleted: thus clients
+/// don't have to worry about the lifetime of the objects.
+/// @brief LLVM Constant Representation
class Constant : public User {
+ void operator=(const Constant &); // Do not implement
+ Constant(const Constant &); // Do not implement
protected:
- Constant(const Type *Ty, ValueTy vty, Use *Ops, unsigned NumOps,
- const std::string& Name = "")
- : User(Ty, vty, Ops, NumOps, Name) {}
+ Constant(const Type *ty, ValueTy vty, Use *Ops, unsigned NumOps)
+ : User(ty, vty, Ops, NumOps) {}
void destroyConstantImpl();
public:
- /// Static constructor to get a '0' constant of arbitrary type...
- ///
- static Constant *getNullValue(const Type *Ty);
-
/// isNullValue - Return true if this is the value that would be returned by
/// getNullValue.
virtual bool isNullValue() const = 0;
- virtual void print(std::ostream &O) const;
+ /// isNegativeZeroValue - Return true if the value is what would be returned
+ /// by getZeroValueForNegation.
+ virtual bool isNegativeZeroValue() const { return isNullValue(); }
- // Specialize get/setOperand for Constant's as their operands are always
+ /// canTrap - Return true if evaluation of this constant could trap. This is
+ /// true for things like constant expressions that could divide by zero.
+ bool canTrap() const;
+
+ /// ContainsRelocations - Return true if the constant value contains
+ /// relocations which cannot be resolved at compile time. Note that answer is
+ /// not exclusive: there can be possibility that relocations of other kind are
+ /// required as well.
+ bool ContainsRelocations(unsigned Kind = Reloc::LocalOrGlobal) const;
+
+ // Specialize get/setOperand for Constants as their operands are always
// constants as well.
Constant *getOperand(unsigned i) {
return static_cast<Constant*>(User::getOperand(i));
void setOperand(unsigned i, Constant *C) {
User::setOperand(i, C);
}
+
+ /// getVectorElements - This method, which is only valid on constant of vector
+ /// type, returns the elements of the vector in the specified smallvector.
+ /// This handles breaking down a vector undef into undef elements, etc. For
+ /// constant exprs and other cases we can't handle, we return an empty vector.
+ void getVectorElements(LLVMContext &Context,
+ SmallVectorImpl<Constant*> &Elts) const;
/// destroyConstant - Called if some element of this constant is no longer
/// valid. At this point only other constants may be on the use_list for this
static inline bool classof(const Constant *) { return true; }
static inline bool classof(const GlobalValue *) { return true; }
static inline bool classof(const Value *V) {
- return V->getValueType() == Value::SimpleConstantVal ||
- V->getValueType() == Value::ConstantExprVal ||
- V->getValueType() == Value::ConstantAggregateZeroVal ||
- V->getValueType() == Value::FunctionVal ||
- V->getValueType() == Value::GlobalVariableVal ||
- V->getValueType() == Value::UndefValueVal;
+ return V->getValueID() >= ConstantFirstVal &&
+ V->getValueID() <= ConstantLastVal;
}
/// replaceUsesOfWithOnConstant - This method is a special form of
/// use Value::replaceAllUsesWith, which automatically dispatches to this
/// method as needed.
///
- virtual void replaceUsesOfWithOnConstant(Value *From, Value *To,
- bool DisableChecking = false) {
+ virtual void replaceUsesOfWithOnConstant(Value *, Value *, Use *) {
// Provide a default implementation for constants (like integers) that
// cannot use any other values. This cannot be called at runtime, but needs
// to be here to avoid link errors.
"implemented for all constants that have operands!");
assert(0 && "Constants that do not have operands cannot be using 'From'!");
}
-
- /// clearAllValueMaps - This method frees all internal memory used by the
- /// constant subsystem, which can be used in environments where this memory
- /// is otherwise reported as a leak.
- static void clearAllValueMaps();
};
} // End llvm namespace
projects / oota-llvm.git / blobdiff