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
23namespace __sanitizer {
24
25# if SANITIZER_CAN_SLOW_UNWIND
26struct 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
42void 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
57void 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