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//===-- sanitizer_symbolizer_markup.cpp -----------------------------------===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// This file is shared between various sanitizers' runtime libraries.
// Implementation of offline markup symbolizer.
#include "sanitizer_platform.h"
#include "sanitizer_symbolizer_fuchsia.h"
# endif
# include <limits.h>
# include <unwind.h>
# include "sanitizer_stacktrace.h"
# include "sanitizer_symbolizer.h"
namespace __sanitizer {
// This generic support for offline symbolizing is based on the
// Fuchsia port. We don't do any actual symbolization per se.
// Instead, we emit text containing raw addresses and raw linkage
// symbol names, embedded in Fuchsia's symbolization markup format.
// Fuchsia's logging infrastructure emits enough information about
// process memory layout that a post-processing filter can do the
// symbolization and pretty-print the markup. See the spec at:
// This is used by UBSan for type names, and by ASan for global variable names.
// It's expected to return a static buffer that will be reused on each call.
const char *Symbolizer::Demangle(const char *name) {
static char buffer[kFormatDemangleMax];
internal_snprintf(buffer, sizeof(buffer), kFormatDemangle, name);
return buffer;
// This is used mostly for suppression matching. Making it work
// would enable "interceptor_via_lib" suppressions. It's also used
// once in UBSan to say "in module ..." in a message that also
// includes an address in the module, so post-processing can already
// pretty-print that so as to indicate the module.
bool Symbolizer::GetModuleNameAndOffsetForPC(uptr pc, const char **module_name,
uptr *module_address) {
return false;
// This is mainly used by hwasan for online symbolization. This isn't needed
// since hwasan can always just dump stack frames for offline symbolization.
bool Symbolizer::SymbolizeFrame(uptr addr, FrameInfo *info) { return false; }
// This is used in some places for suppression checking, which we
// don't really support for Fuchsia. It's also used in UBSan to
// identify a PC location to a function name, so we always fill in
// the function member with a string containing markup around the PC
// value.
// TODO(mcgrathr): Under SANITIZER_GO, it's currently used by TSan
// to render stack frames, but that should be changed to use
// RenderStackFrame.
SymbolizedStack *Symbolizer::SymbolizePC(uptr addr) {
SymbolizedStack *s = SymbolizedStack::New(addr);
char buffer[kFormatFunctionMax];
internal_snprintf(buffer, sizeof(buffer), kFormatFunction, addr);
s->info.function = internal_strdup(buffer);
return s;
// Always claim we succeeded, so that RenderDataInfo will be called.
bool Symbolizer::SymbolizeData(uptr addr, DataInfo *info) {
info->start = addr;
return true;
// We ignore the format argument to __sanitizer_symbolize_global.
void RenderData(InternalScopedString *buffer, const char *format,
const DataInfo *DI, const char *strip_path_prefix) {
buffer->append(kFormatData, DI->start);
bool RenderNeedsSymbolization(const char *format) { return false; }
// We don't support the stack_trace_format flag at all.
void RenderFrame(InternalScopedString *buffer, const char *format, int frame_no,
uptr address, const AddressInfo *info, bool vs_style,
const char *strip_path_prefix, const char *strip_func_prefix) {
buffer->append(kFormatFrame, frame_no, address);
Symbolizer *Symbolizer::PlatformInit() {
return new (symbolizer_allocator_) Symbolizer({});
void Symbolizer::LateInitialize() {
void StartReportDeadlySignal() {}
void ReportDeadlySignal(const SignalContext &sig, u32 tid,
UnwindSignalStackCallbackType unwind,
const void *unwind_context) {}
struct UnwindTraceArg {
BufferedStackTrace *stack;
u32 max_depth;
_Unwind_Reason_Code Unwind_Trace(struct _Unwind_Context *ctx, void *param) {
UnwindTraceArg *arg = static_cast<UnwindTraceArg *>(param);
CHECK_LT(arg->stack->size, arg->max_depth);
uptr pc = _Unwind_GetIP(ctx);
if (pc < PAGE_SIZE) return _URC_NORMAL_STOP;
arg->stack->trace_buffer[arg->stack->size++] = pc;
return (arg->stack->size == arg->max_depth ? _URC_NORMAL_STOP
void BufferedStackTrace::UnwindSlow(uptr pc, u32 max_depth) {
CHECK_GE(max_depth, 2);
size = 0;
UnwindTraceArg arg = {this, Min(max_depth + 1, kStackTraceMax)};
_Unwind_Backtrace(Unwind_Trace, &arg);
CHECK_GT(size, 0);
// We need to pop a few frames so that pc is on top.
uptr to_pop = LocatePcInTrace(pc);
// trace_buffer[0] belongs to the current function so we always pop it,
// unless there is only 1 frame in the stack trace (1 frame is always better
// than 0!).
PopStackFrames(Min(to_pop, static_cast<uptr>(1)));
trace_buffer[0] = pc;
void BufferedStackTrace::UnwindSlow(uptr pc, void *context, u32 max_depth) {
CHECK_GE(max_depth, 2);
UNREACHABLE("signal context doesn't exist");
} // namespace __sanitizer