[ASan/sanitizers] Make stack unwinding better on Windows.

compiler-rt/lib/sanitizer_common/sanitizer_unwind_win.cpp

@@ -43,10 +43,47 @@ void BufferedStackTrace::UnwindSlow(uptr pc, u32 max_depth) {
   trace_buffer[0] = pc;
 }
 
-#ifdef __clang__
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wframe-larger-than="
-#endif
+PVOID CALLBACK FallbackFunctionTableAccess(HANDLE hProcess,
+                                           DWORD64 dwAddrBase) {
+  // First try DbgHelp's function.
+  if (PVOID pResult =
+          __sanitizer::SymFunctionTableAccess64(hProcess, dwAddrBase)) {
+    return pResult;
+  }
+
+  // Fall back to RtlLookupFunctionEntry for dynamic code.
+  // Function registered with RtlAddFunctionTable is not necessarily registered
+  // with DbgHelp, so this is required to cover some edge cases (e.g. JIT
+  // compilers can use Rtl* functions).
+#    if SANITIZER_WINDOWS64
+  DWORD64 dw64ImageBase = 0;
+  return RtlLookupFunctionEntry(dwAddrBase, &dw64ImageBase, nullptr);
+#    else
+  return nullptr;
+#    endif
+}
+
+DWORD64 CALLBACK FallbackGetModuleBase(HANDLE hProcess, DWORD64 dwAddr) {
+  if (DWORD64 dwResult = __sanitizer::SymGetModuleBase64(hProcess, dwAddr)) {
+    return dwResult;
+  }
+
+  // Both GetModuleBase and FunctionTableAccess must provide this fallback,
+  // otherwise dynamic functions won't be properly unwound.
+#    if SANITIZER_WINDOWS64
+  DWORD64 dw64ImageBase = 0;
+  if (RtlLookupFunctionEntry(dwAddr, &dw64ImageBase, nullptr)) {
+    return dw64ImageBase;
+  }
+#    endif
+
+  return 0;
+}
+
+#    ifdef __clang__
+#      pragma clang diagnostic push
+#      pragma clang diagnostic ignored "-Wframe-larger-than="
+#    endif
 void BufferedStackTrace::UnwindSlow(uptr pc, void *context, u32 max_depth) {
   CHECK(context);
   CHECK_GE(max_depth, 2);
@@ -91,8 +128,8 @@ void BufferedStackTrace::UnwindSlow(uptr pc, void *context, u32 max_depth) {
   stack_frame.AddrFrame.Mode = AddrModeFlat;
   stack_frame.AddrStack.Mode = AddrModeFlat;
   while (StackWalk64(machine_type, GetCurrentProcess(), GetCurrentThread(),
-                     &stack_frame, &ctx, NULL, SymFunctionTableAccess64,
-                     SymGetModuleBase64, NULL) &&
+                     &stack_frame, &ctx, NULL, FallbackFunctionTableAccess,
+                     FallbackGetModuleBase, NULL) &&
          size < Min(max_depth, kStackTraceMax)) {
     trace_buffer[size++] = (uptr)stack_frame.AddrPC.Offset;
   }