1 //===- llvm/Support/PointerLikeTypeTraits.h - Pointer Traits ----*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the PointerLikeTypeTraits class. This allows data
11 // structures to reason about pointers and other things that are pointer sized.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_SUPPORT_POINTERLIKETYPETRAITS_H
16 #define LLVM_SUPPORT_POINTERLIKETYPETRAITS_H
20 /// PointerLikeTypeTraits - This is a traits object that is used to handle
21 /// pointer types and things that are just wrappers for pointers as a uniform
24 class PointerLikeTypeTraits {
27 // getNumLowBitsAvailable
30 // Provide PointerLikeTypeTraits for non-cvr pointers.
32 class PointerLikeTypeTraits<T*> {
34 static inline void *getAsVoidPointer(T* P) { return P; }
35 static inline T *getFromVoidPointer(void *P) {
36 return static_cast<T*>(P);
39 /// Note, we assume here that malloc returns objects at least 8-byte aligned.
40 /// However, this may be wrong, or pointers may be from something other than
41 /// malloc. In this case, you should specialize this template to reduce this.
43 /// All clients should use assertions to do a run-time check to ensure that
44 /// this is actually true.
45 static inline unsigned getNumLowBitsAvailable() { return 3; }
48 // Provide PointerLikeTypeTraits for const pointers.
50 class PointerLikeTypeTraits<const T*> {
52 static inline const void *getAsVoidPointer(const T* P) { return P; }
53 static inline const T *getFromVoidPointer(const void *P) {
54 return static_cast<const T*>(P);
56 static inline unsigned getNumLowBitsAvailable() { return 3; }
59 } // end namespace llvm