asan_mapping.h revision 229109 
1//===-- asan_mapping.h ------------------------------------------*- C++ -*-===//
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 is a part of AddressSanitizer, an address sanity checker.
11//
12// Defines ASan memory mapping.
13//===----------------------------------------------------------------------===//
14#ifndef ASAN_MAPPING_H
15#define ASAN_MAPPING_H
16
17#include "asan_internal.h"
18
19// The full explanation of the memory mapping could be found here:
20// http://code.google.com/p/address-sanitizer/wiki/AddressSanitizerAlgorithm
21
22#if ASAN_FLEXIBLE_MAPPING_AND_OFFSET == 1
23extern __attribute__((visibility("default"))) uintptr_t __asan_mapping_scale;
24extern __attribute__((visibility("default"))) uintptr_t __asan_mapping_offset;
25#define SHADOW_SCALE (__asan_mapping_scale)
26#define SHADOW_OFFSET (__asan_mapping_offset)
27#else
28#define SHADOW_SCALE (3)
29#if __WORDSIZE == 32
30#define SHADOW_OFFSET (1 << 29)
31#else
32#define SHADOW_OFFSET (1ULL << 44)
33#endif
34#endif  // ASAN_FLEXIBLE_MAPPING_AND_OFFSET
35
36#define SHADOW_GRANULARITY (1ULL << SHADOW_SCALE)
37#define MEM_TO_SHADOW(mem) (((mem) >> SHADOW_SCALE) | (SHADOW_OFFSET))
38
39#if __WORDSIZE == 64
40  static const size_t kHighMemEnd = 0x00007fffffffffffUL;
41#else  // __WORDSIZE == 32
42  static const size_t kHighMemEnd = 0xffffffff;
43#endif  // __WORDSIZE
44
45
46#define kLowMemBeg      0
47#define kLowMemEnd      (SHADOW_OFFSET ? SHADOW_OFFSET - 1 : 0)
48
49#define kLowShadowBeg   SHADOW_OFFSET
50#define kLowShadowEnd   MEM_TO_SHADOW(kLowMemEnd)
51
52#define kHighMemBeg     (MEM_TO_SHADOW(kHighMemEnd) + 1)
53
54#define kHighShadowBeg  MEM_TO_SHADOW(kHighMemBeg)
55#define kHighShadowEnd  MEM_TO_SHADOW(kHighMemEnd)
56
57#define kShadowGapBeg   (kLowShadowEnd ? kLowShadowEnd + 1 : 16 * kPageSize)
58#define kShadowGapEnd   (kHighShadowBeg - 1)
59
60#define kGlobalAndStackRedzone \
61      (SHADOW_GRANULARITY < 32 ? 32 : SHADOW_GRANULARITY)
62
63namespace __asan {
64
65static inline bool AddrIsInLowMem(uintptr_t a) {
66  return a < kLowMemEnd;
67}
68
69static inline bool AddrIsInLowShadow(uintptr_t a) {
70  return a >= kLowShadowBeg && a <= kLowShadowEnd;
71}
72
73static inline bool AddrIsInHighMem(uintptr_t a) {
74  return a >= kHighMemBeg && a <= kHighMemEnd;
75}
76
77static inline bool AddrIsInMem(uintptr_t a) {
78  return AddrIsInLowMem(a) || AddrIsInHighMem(a);
79}
80
81static inline uintptr_t MemToShadow(uintptr_t p) {
82  CHECK(AddrIsInMem(p));
83  return MEM_TO_SHADOW(p);
84}
85
86static inline bool AddrIsInHighShadow(uintptr_t a) {
87  return a >= kHighShadowBeg && a <=  kHighMemEnd;
88}
89
90static inline bool AddrIsInShadow(uintptr_t a) {
91  return AddrIsInLowShadow(a) || AddrIsInHighShadow(a);
92}
93
94static inline bool AddrIsAlignedByGranularity(uintptr_t a) {
95  return (a & (SHADOW_GRANULARITY - 1)) == 0;
96}
97
98}  // namespace __asan
99
100#endif  // ASAN_MAPPING_H
101