asan_stack.cc revision b9a30e0799787a99147e2587ef5ecc8c5f224160
1//===-- asan_stack.cc -----------------------------------------------------===// 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// Code for ASan stack trace. 13//===----------------------------------------------------------------------===// 14#include "asan_interceptors.h" 15#include "asan_lock.h" 16#include "asan_procmaps.h" 17#include "asan_stack.h" 18#include "asan_thread.h" 19#include "asan_thread_registry.h" 20#include "sanitizer_common/sanitizer_symbolizer.h" 21 22#ifdef ASAN_USE_EXTERNAL_SYMBOLIZER 23extern bool 24ASAN_USE_EXTERNAL_SYMBOLIZER(const void *pc, char *out, int out_size); 25#endif 26 27namespace __asan { 28 29// ----------------------- AsanStackTrace ----------------------------- {{{1 30#if defined(ASAN_USE_EXTERNAL_SYMBOLIZER) 31void AsanStackTrace::PrintStack(uptr *addr, uptr size) { 32 for (uptr i = 0; i < size && addr[i]; i++) { 33 uptr pc = addr[i]; 34 char buff[4096]; 35 ASAN_USE_EXTERNAL_SYMBOLIZER((void*)pc, buff, sizeof(buff)); 36 Printf(" #%zu 0x%zx %s\n", i, pc, buff); 37 } 38} 39 40#else // ASAN_USE_EXTERNAL_SYMBOLIZER 41void AsanStackTrace::PrintStack(uptr *addr, uptr size) { 42 AsanProcMaps proc_maps; 43 uptr frame_num = 0; 44 for (uptr i = 0; i < size && addr[i]; i++) { 45 proc_maps.Reset(); 46 uptr pc = addr[i]; 47 uptr offset; 48 char filename[4096]; 49 if (FLAG_symbolize) { 50 AddressInfoList *address_info_list = SymbolizeCode(pc); 51 for (AddressInfoList *entry = address_info_list; entry; 52 entry = entry->next) { 53 AddressInfo info = entry->info; 54 Printf(" #%zu 0x%zx %s:%d:%d\n", frame_num, pc, 55 (info.file) ? info.file : "", 56 info.line, info.column); 57 frame_num++; 58 } 59 address_info_list->Clear(); 60 } else { 61 if (proc_maps.GetObjectNameAndOffset(pc, &offset, 62 filename, sizeof(filename))) { 63 Printf(" #%zu 0x%zx (%s+0x%zx)\n", frame_num, pc, filename, 64 offset); 65 } else { 66 Printf(" #%zu 0x%zx\n", frame_num, pc); 67 } 68 frame_num++; 69 } 70 } 71} 72#endif // ASAN_USE_EXTERNAL_SYMBOLIZER 73 74uptr AsanStackTrace::GetCurrentPc() { 75 return GET_CALLER_PC(); 76} 77 78void AsanStackTrace::FastUnwindStack(uptr pc, uptr bp) { 79 CHECK(size == 0 && trace[0] == pc); 80 size = 1; 81 if (!asan_inited) return; 82 AsanThread *t = asanThreadRegistry().GetCurrent(); 83 if (!t) return; 84 uptr *frame = (uptr*)bp; 85 uptr *prev_frame = frame; 86 uptr *top = (uptr*)t->stack_top(); 87 uptr *bottom = (uptr*)t->stack_bottom(); 88 while (frame >= prev_frame && 89 frame < top - 2 && 90 frame > bottom && 91 size < max_size) { 92 uptr pc1 = frame[1]; 93 if (pc1 != pc) { 94 trace[size++] = pc1; 95 } 96 prev_frame = frame; 97 frame = (uptr*)frame[0]; 98 } 99} 100 101// On 32-bits we don't compress stack traces. 102// On 64-bits we compress stack traces: if a given pc differes slightly from 103// the previous one, we record a 31-bit offset instead of the full pc. 104uptr AsanStackTrace::CompressStack(AsanStackTrace *stack, 105 u32 *compressed, uptr size) { 106#if __WORDSIZE == 32 107 // Don't compress, just copy. 108 uptr res = 0; 109 for (uptr i = 0; i < stack->size && i < size; i++) { 110 compressed[i] = stack->trace[i]; 111 res++; 112 } 113 if (stack->size < size) 114 compressed[stack->size] = 0; 115#else // 64 bits, compress. 116 uptr prev_pc = 0; 117 const uptr kMaxOffset = (1ULL << 30) - 1; 118 uptr c_index = 0; 119 uptr res = 0; 120 for (uptr i = 0, n = stack->size; i < n; i++) { 121 uptr pc = stack->trace[i]; 122 if (!pc) break; 123 if ((s64)pc < 0) break; 124 // Printf("C pc[%zu] %zx\n", i, pc); 125 if (prev_pc - pc < kMaxOffset || pc - prev_pc < kMaxOffset) { 126 uptr offset = (s64)(pc - prev_pc); 127 offset |= (1U << 31); 128 if (c_index >= size) break; 129 // Printf("C co[%zu] offset %zx\n", i, offset); 130 compressed[c_index++] = offset; 131 } else { 132 uptr hi = pc >> 32; 133 uptr lo = (pc << 32) >> 32; 134 CHECK((hi & (1 << 31)) == 0); 135 if (c_index + 1 >= size) break; 136 // Printf("C co[%zu] hi/lo: %zx %zx\n", c_index, hi, lo); 137 compressed[c_index++] = hi; 138 compressed[c_index++] = lo; 139 } 140 res++; 141 prev_pc = pc; 142 } 143 if (c_index < size) 144 compressed[c_index] = 0; 145 if (c_index + 1 < size) 146 compressed[c_index + 1] = 0; 147#endif // __WORDSIZE 148 149 // debug-only code 150#if 0 151 AsanStackTrace check_stack; 152 UncompressStack(&check_stack, compressed, size); 153 if (res < check_stack.size) { 154 Printf("res %zu check_stack.size %zu; c_size %zu\n", res, 155 check_stack.size, size); 156 } 157 // |res| may be greater than check_stack.size, because 158 // UncompressStack(CompressStack(stack)) eliminates the 0x0 frames. 159 CHECK(res >= check_stack.size); 160 CHECK(0 == REAL(memcmp)(check_stack.trace, stack->trace, 161 check_stack.size * sizeof(uptr))); 162#endif 163 164 return res; 165} 166 167void AsanStackTrace::UncompressStack(AsanStackTrace *stack, 168 u32 *compressed, uptr size) { 169#if __WORDSIZE == 32 170 // Don't uncompress, just copy. 171 stack->size = 0; 172 for (uptr i = 0; i < size && i < kStackTraceMax; i++) { 173 if (!compressed[i]) break; 174 stack->size++; 175 stack->trace[i] = compressed[i]; 176 } 177#else // 64 bits, uncompress 178 uptr prev_pc = 0; 179 stack->size = 0; 180 for (uptr i = 0; i < size && stack->size < kStackTraceMax; i++) { 181 u32 x = compressed[i]; 182 uptr pc = 0; 183 if (x & (1U << 31)) { 184 // Printf("U co[%zu] offset: %x\n", i, x); 185 // this is an offset 186 s32 offset = x; 187 offset = (offset << 1) >> 1; // remove the 31-byte and sign-extend. 188 pc = prev_pc + offset; 189 CHECK(pc); 190 } else { 191 // CHECK(i + 1 < size); 192 if (i + 1 >= size) break; 193 uptr hi = x; 194 uptr lo = compressed[i+1]; 195 // Printf("U co[%zu] hi/lo: %zx %zx\n", i, hi, lo); 196 i++; 197 pc = (hi << 32) | lo; 198 if (!pc) break; 199 } 200 // Printf("U pc[%zu] %zx\n", stack->size, pc); 201 stack->trace[stack->size++] = pc; 202 prev_pc = pc; 203 } 204#endif // __WORDSIZE 205} 206 207} // namespace __asan 208