624011 - jsval.h:301:9: warning: type of bit-field ‘payload47’ is a GCC extension

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Daniel Holbert [:dholbert]]

When building mozilla-central, I get at least 11 instances of this warning:
In file included from ../../dist/include/jspubtd.h:47:0,
                 from ../../dist/include/jsapi.h:49,
                 from ../../../mozilla/js/jsd/jsdebug.h:57,
                 from ../../../mozilla/js/jsd/jsd.h:81,
                 from ../../../mozilla/js/jsd/jsd_step.c:42:
../../dist/include/jsval.h:301:9: warning: type of bit-field 'payload47' is a GCC extension

This triggers tons of warning-spam, since jsval.h is indirectly included by multiple files, and most instances of the warning are prefixed with 4-6 lines of "included from..." as above.

The line of code that's flagged by the warning is:
> 301         uint64             payload47 : 47;
which was added in bug 549143.

Maybe we should just disable this GCC warning (maybe just for this chunk of code)?

Comment 1

[Luke Wagner [:luke]]

Ohh, are all the warnings from .c files?

Comment 2

[Daniel Holbert [:dholbert]]

Looks like it.  Here's the biggest (only?) chunk of this warning-spam that I see (in a build with -j10 so some stuff might be out-of-order) -- looks like the final line in each of these is a .c file.

{
jsd_text.c
In file included from ../../dist/include/jspubtd.h:47:0,
                 from ../../dist/include/jsapi.h:49,
                 from ../../../mozilla/js/jsd/jsdebug.h:57,
                 from ../../../mozilla/js/jsd/jsd.h:81,
                 from ../../../mozilla/js/jsd/jsdebug.c:42:
../../dist/include/jsval.h:301:9: warning: type of bit-field ‘payload47’ is a GCC extension
../../../mozilla/js/jsd/jsdebug.c: In function ‘JSD_EnableSingleStepInterrupts’:
../../../mozilla/js/jsd/jsdebug.c:584:5: warning: implicit declaration of function ‘jsd_EnableSingleStepInterrupts’
jsd_val.c
In file included from ../../dist/include/jspubtd.h:47:0,
                 from ../../dist/include/jsapi.h:49,
                 from ../../../mozilla/js/jsd/jsdebug.h:57,
                 from ../../../mozilla/js/jsd/jsd.h:81,
                 from ../../../mozilla/js/jsd/jsd_lock.c:50:
../../dist/include/jsval.h:301:9: warning: type of bit-field 'payload47' is a GCC extension
jsd_xpc.cpp
In file included from ../../dist/include/jspubtd.h:47:0,
                 from ../../dist/include/jsapi.h:49,
                 from ../../../mozilla/js/jsd/jsdebug.h:57,
                 from ../../../mozilla/js/jsd/jsd.h:81,
                 from ../../../mozilla/js/jsd/jsd_hook.c:42:
../../dist/include/jsval.h:301:9: warning: type of bit-field ‘payload47’ is a GCC extension
In file included from ../../dist/include/jspubtd.h:47:0,
                 from ../../dist/include/jsapi.h:49,
                 from ../../../mozilla/js/jsd/jsdebug.h:57,
                 from ../../../mozilla/js/jsd/jsd.h:81,
                 from ../../../mozilla/js/jsd/jsd_atom.c:42:
../../dist/include/jsval.h:301:9: warning: type of bit-field ‘payload47’ is a GCC extension
In file included from ../../dist/include/jspubtd.h:47:0,
                 from ../../dist/include/jsapi.h:49,
                 from ../../../mozilla/js/jsd/jsdebug.h:57,
                 from ../../../mozilla/js/jsd/jsd.h:81,
                 from ../../../mozilla/js/jsd/jsd_val.c:42:
../../dist/include/jsval.h:301:9: warning: type of bit-field ‘payload47’ is a GCC extension
In file included from ../../dist/include/jspubtd.h:47:0,
                 from ../../dist/include/jsapi.h:49,
                 from ../../../mozilla/js/jsd/jsdebug.h:57,
                 from ../../../mozilla/js/jsd/jsd.h:81,
                 from ../../../mozilla/js/jsd/jsd_high.c:42:
../../dist/include/jsval.h:301:9: warning: type of bit-field 'payload47' is a GCC extension
In file included from ../../dist/include/jspubtd.h:47:0,
                 from ../../dist/include/jsapi.h:49,
                 from ../../../mozilla/js/jsd/jsdebug.h:57,
                 from ../../../mozilla/js/jsd/jsd.h:81,
                 from ../../../mozilla/js/jsd/jsd_stak.c:42:
../../dist/include/jsval.h:301:9: warning: type of bit-field 'payload47' is a GCC extension
In file included from ../../dist/include/jspubtd.h:47:0,
                 from ../../dist/include/jsapi.h:49,
                 from ../../../mozilla/js/jsd/jsdebug.h:57,
                 from ../../../mozilla/js/jsd/jsd.h:81,
                 from ../../../mozilla/js/jsd/jsd_obj.c:42:
../../dist/include/jsval.h:301:9: warning: type of bit-field 'payload47' is a GCC extension
../../../mozilla/js/jsd/jsd_obj.c: In function 'jsd_Constructing':
../../../mozilla/js/jsd/jsd_obj.c:161:26: warning: assignment from incompatible pointer type
In file included from ../../dist/include/jspubtd.h:47:0,
                 from ../../dist/include/jsapi.h:49,
                 from ../../../mozilla/js/jsd/jsdebug.h:57,
                 from ../../../mozilla/js/jsd/jsd.h:81,
                 from ../../../mozilla/js/jsd/jsd_step.c:42:
../../dist/include/jsval.h:301:9: warning: type of bit-field 'payload47' is a GCC extension
In file included from ../../dist/include/jspubtd.h:47:0,
                 from ../../dist/include/jsapi.h:49,
                 from ../../../mozilla/js/jsd/jsdebug.h:57,
                 from ../../../mozilla/js/jsd/jsd.h:81,
                 from ../../../mozilla/js/jsd/jsd_text.c:43:
../../dist/include/jsval.h:301:9: warning: type of bit-field ‘payload47’ is a GCC extension
In file included from ../../dist/include/jspubtd.h:47:0,
                 from ../../dist/include/jsapi.h:49,
                 from ../../../mozilla/js/jsd/jsdebug.h:57,
                 from ../../../mozilla/js/jsd/jsd.h:81,
                 from ../../../mozilla/js/jsd/jsd_scpt.c:42:
../../dist/include/jsval.h:301:9: warning: type of bit-field ‘payload47’ is a GCC extension
}

I'm building with gcc-4.5 & g++-4.5 on 64-bit Ubuntu 10.10, FWIW.

Comment 3

[Luke Wagner [:luke]]

Cool, then it looks like we can just #ifdef off C.  This whole struct is, as the name says, just for ease of gdb'ing.

Comment 4

[Daniel Holbert [:dholbert]]

Attachment: fix?

(In reply to comment #3)
> Cool, then it looks like we can just #ifdef off C.

Like so?

Comment 5

[Daniel Holbert [:dholbert]]

(This does seem to fix the build warnings for me, FWIW)

Comment 6

[Luke Wagner [:luke]]

Comment on attachment 502159 [details] [diff] [review]
fix?

It would be a little shorter to do
 #if !(defined(_WIN64) || defined(__cplusplus))

Comment 7

[Daniel Holbert [:dholbert]]

(In reply to comment #6)
> It would be a little shorter to do
>  #if !(defined(_WIN64) || defined(__cplusplus))
I think you mean
   #if (!defined(_WIN64) && defined(__cplusplus))
right?

Comment 8

[Luke Wagner [:luke]]

hehe, yes :)

Comment 9

[Daniel Holbert [:dholbert]]

Landed: http://hg.mozilla.org/tracemonkey/rev/3d9329ed0363

Comment 10

[Chris Leary [:cdleary] (not checking bugmail)]

http://hg.mozilla.org/mozilla-central/rev/3d9329ed0363