| //===-- sanitizer_stacktrace.cc -------------------------------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file is shared between AddressSanitizer and ThreadSanitizer |
| // run-time libraries. |
| //===----------------------------------------------------------------------===// |
| |
| #include "sanitizer_common.h" |
| #include "sanitizer_flags.h" |
| #include "sanitizer_procmaps.h" |
| #include "sanitizer_stacktrace.h" |
| #include "sanitizer_symbolizer.h" |
| |
| namespace __sanitizer { |
| |
| uptr StackTrace::GetPreviousInstructionPc(uptr pc) { |
| #ifdef __arm__ |
| // Cancel Thumb bit. |
| pc = pc & (~1); |
| #endif |
| #if defined(__powerpc__) || defined(__powerpc64__) |
| // PCs are always 4 byte aligned. |
| return pc - 4; |
| #elif defined(__sparc__) |
| return pc - 8; |
| #else |
| return pc - 1; |
| #endif |
| } |
| |
| static void PrintStackFramePrefix(uptr frame_num, uptr pc) { |
| Printf(" #%zu 0x%zx", frame_num, pc); |
| } |
| |
| void StackTrace::PrintStack(const uptr *addr, uptr size, bool symbolize, |
| SymbolizeCallback symbolize_callback) { |
| MemoryMappingLayout proc_maps(/*cache_enabled*/true); |
| InternalScopedBuffer<char> buff(GetPageSizeCached() * 2); |
| InternalScopedBuffer<AddressInfo> addr_frames(64); |
| uptr frame_num = 0; |
| for (uptr i = 0; i < size && addr[i]; i++) { |
| // PCs in stack traces are actually the return addresses, that is, |
| // addresses of the next instructions after the call. |
| uptr pc = GetPreviousInstructionPc(addr[i]); |
| uptr addr_frames_num = 0; // The number of stack frames for current |
| // instruction address. |
| if (symbolize_callback) { |
| if (symbolize_callback((void*)pc, buff.data(), buff.size())) { |
| addr_frames_num = 1; |
| PrintStackFramePrefix(frame_num, pc); |
| // We can't know anything about the string returned by external |
| // symbolizer, but if it starts with filename, try to strip path prefix |
| // from it. |
| Printf(" %s\n", |
| StripPathPrefix(buff.data(), common_flags()->strip_path_prefix)); |
| frame_num++; |
| } |
| } |
| if (symbolize && addr_frames_num == 0 && &getSymbolizer) { |
| // Use our own (online) symbolizer, if necessary. |
| addr_frames_num = getSymbolizer()->SymbolizeCode( |
| pc, addr_frames.data(), addr_frames.size()); |
| for (uptr j = 0; j < addr_frames_num; j++) { |
| AddressInfo &info = addr_frames[j]; |
| PrintStackFramePrefix(frame_num, pc); |
| if (info.function) { |
| Printf(" in %s", info.function); |
| } |
| if (info.file) { |
| Printf(" "); |
| PrintSourceLocation(info.file, info.line, info.column); |
| } else if (info.module) { |
| Printf(" "); |
| PrintModuleAndOffset(info.module, info.module_offset); |
| } |
| Printf("\n"); |
| info.Clear(); |
| frame_num++; |
| } |
| } |
| if (addr_frames_num == 0) { |
| // If online symbolization failed, try to output at least module and |
| // offset for instruction. |
| PrintStackFramePrefix(frame_num, pc); |
| uptr offset; |
| if (proc_maps.GetObjectNameAndOffset(pc, &offset, |
| buff.data(), buff.size(), |
| /* protection */0)) { |
| Printf(" "); |
| PrintModuleAndOffset(buff.data(), offset); |
| } |
| Printf("\n"); |
| frame_num++; |
| } |
| } |
| } |
| |
| uptr StackTrace::GetCurrentPc() { |
| return GET_CALLER_PC(); |
| } |
| |
| void StackTrace::FastUnwindStack(uptr pc, uptr bp, |
| uptr stack_top, uptr stack_bottom, |
| uptr max_depth) { |
| max_size = max_depth; |
| if (max_size == 0) { |
| size = 0; |
| return; |
| } |
| trace[0] = pc; |
| size = 1; |
| uhwptr *frame = (uhwptr *)bp; |
| uhwptr *prev_frame = frame - 1; |
| if (stack_top < 4096) return; // Sanity check for stack top. |
| // Avoid infinite loop when frame == frame[0] by using frame > prev_frame. |
| while (frame > prev_frame && |
| frame < (uhwptr *)stack_top - 2 && |
| frame > (uhwptr *)stack_bottom && |
| IsAligned((uptr)frame, sizeof(*frame)) && |
| size < max_size) { |
| uhwptr pc1 = frame[1]; |
| if (pc1 != pc) { |
| trace[size++] = (uptr) pc1; |
| } |
| prev_frame = frame; |
| frame = (uhwptr *)frame[0]; |
| } |
| } |
| |
| void StackTrace::PopStackFrames(uptr count) { |
| CHECK(size >= count); |
| size -= count; |
| for (uptr i = 0; i < size; i++) { |
| trace[i] = trace[i + count]; |
| } |
| } |
| |
| // On 32-bits we don't compress stack traces. |
| // On 64-bits we compress stack traces: if a given pc differes slightly from |
| // the previous one, we record a 31-bit offset instead of the full pc. |
| SANITIZER_INTERFACE_ATTRIBUTE |
| uptr StackTrace::CompressStack(StackTrace *stack, u32 *compressed, uptr size) { |
| #if SANITIZER_WORDSIZE == 32 |
| // Don't compress, just copy. |
| uptr res = 0; |
| for (uptr i = 0; i < stack->size && i < size; i++) { |
| compressed[i] = stack->trace[i]; |
| res++; |
| } |
| if (stack->size < size) |
| compressed[stack->size] = 0; |
| #else // 64 bits, compress. |
| uptr prev_pc = 0; |
| const uptr kMaxOffset = (1ULL << 30) - 1; |
| uptr c_index = 0; |
| uptr res = 0; |
| for (uptr i = 0, n = stack->size; i < n; i++) { |
| uptr pc = stack->trace[i]; |
| if (!pc) break; |
| if ((s64)pc < 0) break; |
| // Printf("C pc[%zu] %zx\n", i, pc); |
| if (prev_pc - pc < kMaxOffset || pc - prev_pc < kMaxOffset) { |
| uptr offset = (s64)(pc - prev_pc); |
| offset |= (1U << 31); |
| if (c_index >= size) break; |
| // Printf("C co[%zu] offset %zx\n", i, offset); |
| compressed[c_index++] = offset; |
| } else { |
| uptr hi = pc >> 32; |
| uptr lo = (pc << 32) >> 32; |
| CHECK_EQ((hi & (1 << 31)), 0); |
| if (c_index + 1 >= size) break; |
| // Printf("C co[%zu] hi/lo: %zx %zx\n", c_index, hi, lo); |
| compressed[c_index++] = hi; |
| compressed[c_index++] = lo; |
| } |
| res++; |
| prev_pc = pc; |
| } |
| if (c_index < size) |
| compressed[c_index] = 0; |
| if (c_index + 1 < size) |
| compressed[c_index + 1] = 0; |
| #endif // SANITIZER_WORDSIZE |
| |
| // debug-only code |
| #if 0 |
| StackTrace check_stack; |
| UncompressStack(&check_stack, compressed, size); |
| if (res < check_stack.size) { |
| Printf("res %zu check_stack.size %zu; c_size %zu\n", res, |
| check_stack.size, size); |
| } |
| // |res| may be greater than check_stack.size, because |
| // UncompressStack(CompressStack(stack)) eliminates the 0x0 frames. |
| CHECK(res >= check_stack.size); |
| CHECK_EQ(0, REAL(memcmp)(check_stack.trace, stack->trace, |
| check_stack.size * sizeof(uptr))); |
| #endif |
| |
| return res; |
| } |
| |
| SANITIZER_INTERFACE_ATTRIBUTE |
| void StackTrace::UncompressStack(StackTrace *stack, |
| u32 *compressed, uptr size) { |
| #if SANITIZER_WORDSIZE == 32 |
| // Don't uncompress, just copy. |
| stack->size = 0; |
| for (uptr i = 0; i < size && i < kStackTraceMax; i++) { |
| if (!compressed[i]) break; |
| stack->size++; |
| stack->trace[i] = compressed[i]; |
| } |
| #else // 64 bits, uncompress |
| uptr prev_pc = 0; |
| stack->size = 0; |
| for (uptr i = 0; i < size && stack->size < kStackTraceMax; i++) { |
| u32 x = compressed[i]; |
| uptr pc = 0; |
| if (x & (1U << 31)) { |
| // Printf("U co[%zu] offset: %x\n", i, x); |
| // this is an offset |
| s32 offset = x; |
| offset = (offset << 1) >> 1; // remove the 31-byte and sign-extend. |
| pc = prev_pc + offset; |
| CHECK(pc); |
| } else { |
| // CHECK(i + 1 < size); |
| if (i + 1 >= size) break; |
| uptr hi = x; |
| uptr lo = compressed[i+1]; |
| // Printf("U co[%zu] hi/lo: %zx %zx\n", i, hi, lo); |
| i++; |
| pc = (hi << 32) | lo; |
| if (!pc) break; |
| } |
| // Printf("U pc[%zu] %zx\n", stack->size, pc); |
| stack->trace[stack->size++] = pc; |
| prev_pc = pc; |
| } |
| #endif // SANITIZER_WORDSIZE |
| } |
| |
| } // namespace __sanitizer |