237 lines
7.9 KiB
C++
237 lines
7.9 KiB
C++
//===-- asan_mapping.h ------------------------------------------*- C++ -*-===//
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file is a part of AddressSanitizer, an address sanity checker.
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//
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// Defines ASan memory mapping.
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//===----------------------------------------------------------------------===//
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#ifndef ASAN_MAPPING_H
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#define ASAN_MAPPING_H
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#include "asan_internal.h"
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// The full explanation of the memory mapping could be found here:
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// http://code.google.com/p/address-sanitizer/wiki/AddressSanitizerAlgorithm
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//
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// Typical shadow mapping on Linux/x86_64 with SHADOW_OFFSET == 0x00007fff8000:
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// || `[0x10007fff8000, 0x7fffffffffff]` || HighMem ||
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// || `[0x02008fff7000, 0x10007fff7fff]` || HighShadow ||
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// || `[0x00008fff7000, 0x02008fff6fff]` || ShadowGap ||
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// || `[0x00007fff8000, 0x00008fff6fff]` || LowShadow ||
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// || `[0x000000000000, 0x00007fff7fff]` || LowMem ||
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//
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// When SHADOW_OFFSET is zero (-pie):
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// || `[0x100000000000, 0x7fffffffffff]` || HighMem ||
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// || `[0x020000000000, 0x0fffffffffff]` || HighShadow ||
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// || `[0x000000040000, 0x01ffffffffff]` || ShadowGap ||
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//
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// Special case when something is already mapped between
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// 0x003000000000 and 0x005000000000 (e.g. when prelink is installed):
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// || `[0x10007fff8000, 0x7fffffffffff]` || HighMem ||
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// || `[0x02008fff7000, 0x10007fff7fff]` || HighShadow ||
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// || `[0x005000000000, 0x02008fff6fff]` || ShadowGap3 ||
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// || `[0x003000000000, 0x004fffffffff]` || MidMem ||
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// || `[0x000a7fff8000, 0x002fffffffff]` || ShadowGap2 ||
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// || `[0x00067fff8000, 0x000a7fff7fff]` || MidShadow ||
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// || `[0x00008fff7000, 0x00067fff7fff]` || ShadowGap ||
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// || `[0x00007fff8000, 0x00008fff6fff]` || LowShadow ||
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// || `[0x000000000000, 0x00007fff7fff]` || LowMem ||
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//
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// Default Linux/i386 mapping:
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// || `[0x40000000, 0xffffffff]` || HighMem ||
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// || `[0x28000000, 0x3fffffff]` || HighShadow ||
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// || `[0x24000000, 0x27ffffff]` || ShadowGap ||
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// || `[0x20000000, 0x23ffffff]` || LowShadow ||
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// || `[0x00000000, 0x1fffffff]` || LowMem ||
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//
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// Default Linux/MIPS mapping:
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// || `[0x2aaa8000, 0xffffffff]` || HighMem ||
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// || `[0x0fffd000, 0x2aaa7fff]` || HighShadow ||
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// || `[0x0bffd000, 0x0fffcfff]` || ShadowGap ||
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// || `[0x0aaa8000, 0x0bffcfff]` || LowShadow ||
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// || `[0x00000000, 0x0aaa7fff]` || LowMem ||
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static const u64 kDefaultShadowScale = 3;
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static const u64 kDefaultShadowOffset32 = 1ULL << 29;
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static const u64 kDefaultShadowOffset64 = 1ULL << 44;
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static const u64 kDefaultShort64bitShadowOffset = 0x7FFF8000; // < 2G.
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static const u64 kPPC64_ShadowOffset64 = 1ULL << 41;
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static const u64 kMIPS32_ShadowOffset32 = 0x0aaa8000;
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#if ASAN_FLEXIBLE_MAPPING_AND_OFFSET == 1
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extern "C" SANITIZER_INTERFACE_ATTRIBUTE uptr __asan_mapping_scale;
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extern "C" SANITIZER_INTERFACE_ATTRIBUTE uptr __asan_mapping_offset;
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# define SHADOW_SCALE (__asan_mapping_scale)
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# define SHADOW_OFFSET (__asan_mapping_offset)
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#else
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# define SHADOW_SCALE kDefaultShadowScale
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# if SANITIZER_ANDROID
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# define SHADOW_OFFSET (0)
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# else
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# if SANITIZER_WORDSIZE == 32
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# if defined(__mips__)
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# define SHADOW_OFFSET kMIPS32_ShadowOffset32
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# else
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# define SHADOW_OFFSET kDefaultShadowOffset32
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# endif
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# else
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# if defined(__powerpc64__)
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# define SHADOW_OFFSET kPPC64_ShadowOffset64
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# elif SANITIZER_MAC
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# define SHADOW_OFFSET kDefaultShadowOffset64
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# else
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# define SHADOW_OFFSET kDefaultShort64bitShadowOffset
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# endif
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# endif
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# endif
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#endif // ASAN_FLEXIBLE_MAPPING_AND_OFFSET
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#define SHADOW_GRANULARITY (1ULL << SHADOW_SCALE)
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#define MEM_TO_SHADOW(mem) (((mem) >> SHADOW_SCALE) + (SHADOW_OFFSET))
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#define SHADOW_TO_MEM(shadow) (((shadow) - SHADOW_OFFSET) << SHADOW_SCALE)
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#define kLowMemBeg 0
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#define kLowMemEnd (SHADOW_OFFSET ? SHADOW_OFFSET - 1 : 0)
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#define kLowShadowBeg SHADOW_OFFSET
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#define kLowShadowEnd MEM_TO_SHADOW(kLowMemEnd)
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#define kHighMemBeg (MEM_TO_SHADOW(kHighMemEnd) + 1)
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#define kHighShadowBeg MEM_TO_SHADOW(kHighMemBeg)
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#define kHighShadowEnd MEM_TO_SHADOW(kHighMemEnd)
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# define kMidShadowBeg MEM_TO_SHADOW(kMidMemBeg)
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# define kMidShadowEnd MEM_TO_SHADOW(kMidMemEnd)
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// With the zero shadow base we can not actually map pages starting from 0.
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// This constant is somewhat arbitrary.
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#define kZeroBaseShadowStart (1 << 18)
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#define kShadowGapBeg (kLowShadowEnd ? kLowShadowEnd + 1 \
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: kZeroBaseShadowStart)
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#define kShadowGapEnd ((kMidMemBeg ? kMidShadowBeg : kHighShadowBeg) - 1)
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#define kShadowGap2Beg (kMidMemBeg ? kMidShadowEnd + 1 : 0)
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#define kShadowGap2End (kMidMemBeg ? kMidMemBeg - 1 : 0)
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#define kShadowGap3Beg (kMidMemBeg ? kMidMemEnd + 1 : 0)
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#define kShadowGap3End (kMidMemBeg ? kHighShadowBeg - 1 : 0)
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#define DO_ASAN_MAPPING_PROFILE 0 // Set to 1 to profile the functions below.
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#if DO_ASAN_MAPPING_PROFILE
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# define PROFILE_ASAN_MAPPING() AsanMappingProfile[__LINE__]++;
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#else
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# define PROFILE_ASAN_MAPPING()
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#endif
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// If 1, all shadow boundaries are constants.
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// Don't set to 1 other than for testing.
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#define ASAN_FIXED_MAPPING 0
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namespace __asan {
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extern uptr AsanMappingProfile[];
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#if ASAN_FIXED_MAPPING
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// Fixed mapping for 64-bit Linux. Mostly used for performance comparison
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// with non-fixed mapping. As of r175253 (Feb 2013) the performance
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// difference between fixed and non-fixed mapping is below the noise level.
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static uptr kHighMemEnd = 0x7fffffffffffULL;
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static uptr kMidMemBeg = 0x3000000000ULL;
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static uptr kMidMemEnd = 0x4fffffffffULL;
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#else
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extern uptr kHighMemEnd, kMidMemBeg, kMidMemEnd; // Initialized in __asan_init.
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#endif
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static inline bool AddrIsInLowMem(uptr a) {
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PROFILE_ASAN_MAPPING();
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return a < kLowMemEnd;
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}
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static inline bool AddrIsInLowShadow(uptr a) {
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PROFILE_ASAN_MAPPING();
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return a >= kLowShadowBeg && a <= kLowShadowEnd;
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}
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static inline bool AddrIsInHighMem(uptr a) {
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PROFILE_ASAN_MAPPING();
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return a >= kHighMemBeg && a <= kHighMemEnd;
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}
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static inline bool AddrIsInMidMem(uptr a) {
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PROFILE_ASAN_MAPPING();
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return kMidMemBeg && a >= kMidMemBeg && a <= kMidMemEnd;
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}
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static inline bool AddrIsInMem(uptr a) {
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PROFILE_ASAN_MAPPING();
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return AddrIsInLowMem(a) || AddrIsInMidMem(a) || AddrIsInHighMem(a);
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}
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static inline uptr MemToShadow(uptr p) {
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PROFILE_ASAN_MAPPING();
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CHECK(AddrIsInMem(p));
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return MEM_TO_SHADOW(p);
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}
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static inline bool AddrIsInHighShadow(uptr a) {
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PROFILE_ASAN_MAPPING();
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return a >= kHighShadowBeg && a <= kHighMemEnd;
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}
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static inline bool AddrIsInMidShadow(uptr a) {
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PROFILE_ASAN_MAPPING();
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return kMidMemBeg && a >= kMidShadowBeg && a <= kMidMemEnd;
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}
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static inline bool AddrIsInShadow(uptr a) {
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PROFILE_ASAN_MAPPING();
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return AddrIsInLowShadow(a) || AddrIsInMidShadow(a) || AddrIsInHighShadow(a);
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}
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static inline bool AddrIsInShadowGap(uptr a) {
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PROFILE_ASAN_MAPPING();
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if (kMidMemBeg) {
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if (a <= kShadowGapEnd)
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return SHADOW_OFFSET == 0 || a >= kShadowGapBeg;
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return (a >= kShadowGap2Beg && a <= kShadowGap2End) ||
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(a >= kShadowGap3Beg && a <= kShadowGap3End);
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}
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// In zero-based shadow mode we treat addresses near zero as addresses
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// in shadow gap as well.
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if (SHADOW_OFFSET == 0)
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return a <= kShadowGapEnd;
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return a >= kShadowGapBeg && a <= kShadowGapEnd;
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}
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static inline bool AddrIsAlignedByGranularity(uptr a) {
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PROFILE_ASAN_MAPPING();
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return (a & (SHADOW_GRANULARITY - 1)) == 0;
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}
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static inline bool AddressIsPoisoned(uptr a) {
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PROFILE_ASAN_MAPPING();
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const uptr kAccessSize = 1;
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u8 *shadow_address = (u8*)MEM_TO_SHADOW(a);
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s8 shadow_value = *shadow_address;
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if (shadow_value) {
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u8 last_accessed_byte = (a & (SHADOW_GRANULARITY - 1))
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+ kAccessSize - 1;
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return (last_accessed_byte >= shadow_value);
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}
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return false;
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}
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// Must be after all calls to PROFILE_ASAN_MAPPING().
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static const uptr kAsanMappingProfileSize = __LINE__;
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} // namespace __asan
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#endif // ASAN_MAPPING_H
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