[tracing] Fix endianness problem when using booleans

Milad Farazmand · Commit Bot · commit f83b1b3beb4b · 2019-11-08T13:35:41.000Z
All the data types defined under ArgValue are 8 bytes expect "bool as_bool". When casting to <uint64_t> under "tracing/trace-event.h", boolean gets placed on the lower byte of the memory on LE, and on the higher byte on BE machines. When using a "Union" to read back the value as a boolean, only the lower byte of the memory location is read which makes it fine on LE machines, however the value will not be present on BE machines. Using an 8 byte data type as boolean will assure the entire filed is read instead of only the lower byte. Change-Id: I0740b9c019588c963a4c7878af60c6df04827141 TBR: petermarshall@chromium.org Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1896835 Commit-Queue: Ulan Degenbaev <ulan@chromium.org> Reviewed-by: Junliang Yan <jyan@ca.ibm.com> Reviewed-by: Michael Lippautz <mlippautz@chromium.org> Reviewed-by: Ulan Degenbaev <ulan@chromium.org> Reviewed-by: Clemens Backes <clemensb@chromium.org> Cr-Commit-Position: refs/heads/master@{#64859}
diff --git a/include/libplatform/v8-tracing.h b/include/libplatform/v8-tracing.h
@@ -35,7 +35,7 @@ const int kTraceMaxNumArgs = 2;
 class V8_PLATFORM_EXPORT TraceObject {
  public:
   union ArgValue {
-    bool as_bool;
+    V8_DEPRECATED("use as_uint ? true : false") bool as_bool;
     uint64_t as_uint;
     int64_t as_int;
     double as_double;
diff --git a/src/libplatform/tracing/trace-writer.cc b/src/libplatform/tracing/trace-writer.cc
@@ -59,7 +59,7 @@ void JSONTraceWriter::AppendArgValue(uint8_t type,
                                      TraceObject::ArgValue value) {
   switch (type) {
     case TRACE_VALUE_TYPE_BOOL:
-      stream_ << (value.as_bool ? "true" : "false");
+      stream_ << (value.as_uint ? "true" : "false");
       break;
     case TRACE_VALUE_TYPE_UINT:
       stream_ << value.as_uint;
diff --git a/src/libplatform/tracing/tracing-controller.cc b/src/libplatform/tracing/tracing-controller.cc
@@ -129,7 +129,7 @@ void AddArgsToTraceProto(
         break;
       }
       case TRACE_VALUE_TYPE_BOOL:
-        arg->set_bool_value(arg_value.as_bool);
+        arg->set_bool_value(arg_value.as_uint);
         break;
       case TRACE_VALUE_TYPE_UINT:
         arg->set_uint_value(arg_value.as_uint);

Original file line number	Diff line number	Diff line change
`@@ -129,7 +129,7 @@ void AddArgsToTraceProto(`
`129`	`129`	`break;`
`130`	`130`	`}`
`131`	`131`	`case TRACE_VALUE_TYPE_BOOL:`
`132`		`- arg->set_bool_value(arg_value.as_bool);`
	`132`	`+ arg->set_bool_value(arg_value.as_uint);`
`133`	`133`	`break;`
`134`	`134`	`case TRACE_VALUE_TYPE_UINT:`
`135`	`135`	`arg->set_uint_value(arg_value.as_uint);`