TypeOrdering.h revision b995d799e146a7d43a3e8311adb54653415434a1 
1//===-------------- TypeOrdering.h - Total ordering for types -------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10//  This file provides a function objects and specializations that
11//  allow QualType values to be sorted, used in std::maps, std::sets,
12//  llvm::DenseMaps, and llvm::DenseSets.
13//
14//===----------------------------------------------------------------------===//
15
16#ifndef LLVM_CLANG_TYPE_ORDERING_H
17#define LLVM_CLANG_TYPE_ORDERING_H
18
19#include "clang/AST/Type.h"
20#include "llvm/ADT/DenseMap.h"
21#include <functional>
22
23namespace clang {
24
25/// QualTypeOrdering - Function object that provides a total ordering
26/// on QualType values.
27struct QualTypeOrdering : std::binary_function<QualType, QualType, bool> {
28  bool operator()(QualType T1, QualType T2) const {
29    return std::less<void*>()(T1.getAsOpaquePtr(), T2.getAsOpaquePtr());
30  }
31};
32
33}
34
35namespace llvm {
36  template<> struct DenseMapInfo<clang::QualType> {
37    static inline clang::QualType getEmptyKey() { return clang::QualType(); }
38
39    static inline clang::QualType getTombstoneKey() {
40      using clang::QualType;
41      return QualType::getFromOpaquePtr(reinterpret_cast<clang::Type *>(-1));
42    }
43
44    static unsigned getHashValue(clang::QualType Val) {
45      return (unsigned)Val.getAsOpaquePtr() ^
46             ((unsigned)Val.getAsOpaquePtr() >> 9);
47    }
48
49    static bool isEqual(clang::QualType LHS, clang::QualType RHS) {
50      return LHS == RHS;
51    }
52
53    static bool isPod() {
54      // QualType isn't *technically* a POD type. However, we can get
55      // away with calling it a POD type since its copy constructor,
56      // copy assignment operator, and destructor are all trivial.
57      return true;
58    }
59  };
60}
61
62#endif
63