900965 - compile failures with gcc 4.6.3 after std::atomic enum support added in bug 888548

Status: RESOLVED FIXED

(Core :: MFBT, defect)

Description

[Ben Kelly [:bkelly, not reviewing]]

After bug 888548 landed I now get many errors like the following with gcc 4.6.3 on ubuntu 12.04:

 0:31.48 TestAtomics.o: In function `Atomic':
 0:31.48 /srv/mozilla-central/obj-x86_64-unknown-linux-gnu/mfbt/tests/../../dist/include/mozilla/Atomics.h:233: undefined reference to `std::atomic<EnumType>::store(EnumType, std::memory_order)'
 0:31.48 TestAtomics.o: In function `mozilla::detail::IntrinsicMemoryOps<EnumType, (mozilla::MemoryOrdering)1>::load(std::atomic<EnumType> const&)'

Comment 1

[Nathan Froyd [:froydnj]]

It looks like the unspecialized std::atomic template doesn't actually have inline definitions for all the functions declared in it in the 4.6 headers.  *boggle*

Comment 2

[Nathan Froyd [:froydnj]]

Attachment: don't use <atomic> on GCC versions before 4.7

The added comment says it all, I think.

Comment 3

[Nathan Froyd [:froydnj]]

Ben, can you confirm that this patch works for you?

Comment 4

[Ben Kelly [:bkelly, not reviewing]]

I think that fixes the issue.  The mfbt compile passes now, although I did not run a full build.

Comment 5

[Jeff Walden [:Waldo]]

Comment on attachment 785069 [details] [diff] [review]
don't use <atomic> on GCC versions before 4.7

Review of attachment 785069 [details] [diff] [review]:
-----------------------------------------------------------------

Fine by me if it works.

Comment 6

[Jason Duell]

Thanks for figuring this out Nathan!

  https://hg.mozilla.org/integration/mozilla-inbound/rev/ada4c3b62233

Comment 7

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/ada4c3b62233