compiler-rt/lib/sanitizer_common/sanitizer_unwind_fuchsia.cpp

   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