1189894 - remove Atomics.h IntrinsicAddSub hack

Status: RESOLVED FIXED

(Core :: MFBT, defect)

Description

[Nathan Froyd [:froydnj]]

This hack was only required for broken headers in GCC 4.6.  Since we
only support GCC 4.7+ now, this hack is no longer necessary.

Comment 1

[Nathan Froyd [:froydnj]]

Attachment: remove Atomics.h IntrinsicAddSub hack

Hooray for removing obsolete code.  Eric requested to review more code, so
giving this one to him!

Comment 2

[Eric Rahm [:erahm]]

Comment on attachment 8641817 [details] [diff] [review]
remove Atomics.h IntrinsicAddSub hack

Review of attachment 8641817 [details] [diff] [review]:
-----------------------------------------------------------------

r=me. It might be good to see a try run w/ the cppunittests just for sanity (assuming |TestPointerWithOrdering| [1] covers this case).

[1] https://hg.mozilla.org/mozilla-central/annotate/2ddec2dedced/mfbt/tests/TestAtomics.cpp#l87

::: mfbt/Atomics.h
@@ +265,5 @@
>  {
>    typedef IntrinsicBase<T*, Order> Base;
>  
>    static T* add(typename Base::ValueType& aPtr, ptrdiff_t aVal)
>    {

Should we add a compiler error if someone tries to use GCC < 4.7, or do we consider wherever it's documented that you need 4.7+ to be good enough?

Comment 3

[Nathan Froyd [:froydnj]]

(In reply to Eric Rahm [:erahm] (out until 8/3) from comment #2)
> ::: mfbt/Atomics.h
> @@ +265,5 @@
> >  {
> >    typedef IntrinsicBase<T*, Order> Base;
> >  
> >    static T* add(typename Base::ValueType& aPtr, ptrdiff_t aVal)
> >    {
> 
> Should we add a compiler error if someone tries to use GCC < 4.7, or do we
> consider wherever it's documented that you need 4.7+ to be good enough?

That's an excellent question; we already have such a check, in an #include that Atomics.h uses, among other files:

http://mxr.mozilla.org/mozilla-central/source/mfbt/Compiler.h#26

Comment 4

[Mike Hommey [:glandium]]

We also reject gcc < 4.7 in configure.

Comment 5

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/d50e76df21a5

Comment 6

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/d50e76df21a5