1 //===------------------ sanitizer_unwind_fuchsia.cpp 2 //---------------------------===// 3 // 4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5 // See https://llvm.org/LICENSE.txt for license information. 6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 /// Sanitizer unwind Fuchsia specific functions. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "sanitizer_platform.h" 15 #if SANITIZER_FUCHSIA 16 17 # include <limits.h> 18 # include <unwind.h> 19 20 # include "sanitizer_common.h" 21 # include "sanitizer_stacktrace.h" 22 23 namespace __sanitizer { 24 25 # if SANITIZER_CAN_SLOW_UNWIND 26 struct UnwindTraceArg { 27 BufferedStackTrace *stack; 28 u32 max_depth; 29 }; 30 31 _Unwind_Reason_Code Unwind_Trace(struct _Unwind_Context *ctx, void *param) { 32 UnwindTraceArg *arg = static_cast<UnwindTraceArg *>(param); 33 CHECK_LT(arg->stack->size, arg->max_depth); 34 uptr pc = _Unwind_GetIP(ctx); 35 if (pc < GetPageSizeCached()) 36 return _URC_NORMAL_STOP; 37 arg->stack->trace_buffer[arg->stack->size++] = pc; 38 return (arg->stack->size == arg->max_depth ? _URC_NORMAL_STOP 39 : _URC_NO_REASON); 40 } 41 42 void BufferedStackTrace::UnwindSlow(uptr pc, u32 max_depth) { 43 CHECK_GE(max_depth, 2); 44 size = 0; 45 UnwindTraceArg arg = {this, Min(max_depth + 1, kStackTraceMax)}; 46 _Unwind_Backtrace(Unwind_Trace, &arg); 47 CHECK_GT(size, 0); 48 // We need to pop a few frames so that pc is on top. 49 uptr to_pop = LocatePcInTrace(pc); 50 // trace_buffer[0] belongs to the current function so we always pop it, 51 // unless there is only 1 frame in the stack trace (1 frame is always better 52 // than 0!). 53 PopStackFrames(Min(to_pop, static_cast<uptr>(1))); 54 trace_buffer[0] = pc; 55 } 56 57 void BufferedStackTrace::UnwindSlow(uptr pc, void *context, u32 max_depth) { 58 CHECK(context); 59 CHECK_GE(max_depth, 2); 60 UNREACHABLE("signal context doesn't exist"); 61 } 62 # endif // SANITIZER_CAN_SLOW_UNWIND 63 64 } // namespace __sanitizer 65 66 #endif // SANITIZER_FUCHSIA 67