1 files changed, 101 insertions, 0 deletions
diff --git a/contrib/llvm-project/compiler-rt/lib/gwp_asan/optional/backtrace_sanitizer_common.cpp b/contrib/llvm-project/compiler-rt/lib/gwp_asan/optional/backtrace_sanitizer_common.cpp
new file mode 100644
index 000000000000..f8b9cbdb7935
--- /dev/null
+++ b/contrib/llvm-project/compiler-rt/lib/gwp_asan/optional/backtrace_sanitizer_common.cpp
@@ -0,0 +1,101 @@
+//===-- backtrace_sanitizer_common.cpp --------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <assert.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+
+#include "gwp_asan/optional/backtrace.h"
+#include "gwp_asan/options.h"
+#include "sanitizer_common/sanitizer_common.h"
+#include "sanitizer_common/sanitizer_flag_parser.h"
+#include "sanitizer_common/sanitizer_flags.h"
+#include "sanitizer_common/sanitizer_stacktrace.h"
+
+void __sanitizer::BufferedStackTrace::UnwindImpl(uptr pc, uptr bp,
+                                                 void *context,
+                                                 bool request_fast,
+                                                 u32 max_depth) {
+  if (!StackTrace::WillUseFastUnwind(request_fast))
+    return Unwind(max_depth, pc, 0, context, 0, 0, false);
+
+  uptr top = 0;
+  uptr bottom = 0;
+  GetThreadStackTopAndBottom(/*at_initialization*/ false, &top, &bottom);
+
+  return Unwind(max_depth, pc, bp, context, top, bottom, request_fast);
+}
+
+namespace {
+size_t BacktraceCommon(uintptr_t *TraceBuffer, size_t Size, void *Context) {
+  // Use the slow sanitizer unwinder in the segv handler. Fast frame pointer
+  // unwinders can end up dropping frames because the kernel sigreturn() frame's
+  // return address is the return address at time of fault. This has the result
+  // of never actually capturing the PC where the signal was raised.
+  bool UseFastUnwind = (Context == nullptr);
+
+  __sanitizer::BufferedStackTrace Trace;
+  Trace.Reset();
+  if (Size > __sanitizer::kStackTraceMax)
+    Size = __sanitizer::kStackTraceMax;
+
+  Trace.Unwind((__sanitizer::uptr)__builtin_return_address(0),
+               (__sanitizer::uptr)__builtin_frame_address(0), Context,
+               UseFastUnwind, Size - 1);
+
+  memcpy(TraceBuffer, Trace.trace, Trace.size * sizeof(uintptr_t));
+  return Trace.size;
+}
+
+size_t Backtrace(uintptr_t *TraceBuffer, size_t Size) {
+  return BacktraceCommon(TraceBuffer, Size, nullptr);
+}
+
+size_t SegvBacktrace(uintptr_t *TraceBuffer, size_t Size, void *Context) {
+  return BacktraceCommon(TraceBuffer, Size, Context);
+}
+
+static void PrintBacktrace(uintptr_t *Trace, size_t TraceLength,
+                           gwp_asan::Printf_t Printf) {
+  __sanitizer::StackTrace StackTrace;
+  StackTrace.trace = reinterpret_cast<__sanitizer::uptr *>(Trace);
+  StackTrace.size = TraceLength;
+
+  if (StackTrace.size == 0) {
+    Printf("  <unknown (does your allocator support backtracing?)>\n\n");
+    return;
+  }
+
+  __sanitizer::InternalScopedString buffer;
+  StackTrace.PrintTo(&buffer);
+  Printf("%s\n", buffer.data());
+}
+} // anonymous namespace
+
+namespace gwp_asan {
+namespace backtrace {
+
+// This function is thread-compatible. It must be synchronised in respect to any
+// other calls to getBacktraceFunction(), calls to getPrintBacktraceFunction(),
+// and calls to either of the functions that they return. Furthermore, this may
+// require synchronisation with any calls to sanitizer_common that use flags.
+// Generally, this function will be called during the initialisation of the
+// allocator, which is done in a thread-compatible manner.
+options::Backtrace_t getBacktraceFunction() {
+  // The unwinder requires the default flags to be set.
+  __sanitizer::SetCommonFlagsDefaults();
+  __sanitizer::InitializeCommonFlags();
+  return Backtrace;
+}
+
+PrintBacktrace_t getPrintBacktraceFunction() { return PrintBacktrace; }
+SegvBacktrace_t getSegvBacktraceFunction() { return SegvBacktrace; }
+
+} // namespace backtrace
+} // namespace gwp_asan