Mbed-os: uVision compile after export broken

[chrissnow]

Description

Compiling with uVision seems very broken, I have tried on a LPC1768 and STM board and get thousands of errors
compile errors against mbed-os master
lpc1768 errors.txt

compiling with CLI works fine

5.13 compiles fine so it must be something fairly recent.

Issue request type

[ ] Question
[ ] Enhancement
[x] Bug

[0xc0170]

Can be reproduced with blinky? I'll run some tests tomorrow morning.

I can see the failures in the nightly http://mbed-os-ci.s3-website-eu-west-1.amazonaws.com/?prefix=jenkins-ci/ARMmbed/mbed-os/mbed-os-ci-nightly/artifacts/master/307/exporter/FAIL/uvision6/ 😭

cc @ARMmbed/mbed-os-test

[chrissnow]

@0xc0170 Blinky does the same.

[ciarmcom]

Internal Jira reference: https://jira.arm.com/browse/MBOCUSTRIA-1608

[0xc0170]

@kjbracey-arm Reviewing the logs, this looks like related to the latest C++1x change.

See the above fail uvision6 logs. I fetched this one http://mbed-os-ci.s3-website-eu-west-1.amazonaws.com/?prefix=jenkins-ci/ARMmbed/mbed-os/mbed-os-ci-nightly/artifacts/master/307/exporter/FAIL/uvision6/NUCLEO_F412ZG/

./main.cpp(6): warning: In file included from...mbed-os\mbed.h(26): warning: In file included from...mbed-os/features\netsocket/nsapi.h(40): warning: In file included from...mbed-os/features\netsocket/UDPSocket.h(23): warning: In file included from...mbed-os/features\netsocket/InternetSocket.h(28): warning: In file included from...mbed-os/platform\mbed_atomic.h(884): warning: In file included from...mbed-os/platform/cxxsupport\mstd_type_traits(1088): error: no member named 'remove_cv_t' in namespace 'std'; did you mean 'remove_cv'?
using std::remove_cv_t;
      ~~~~~^~~~~~~~~~~
           remove_cv

Only some targets failed in the nightly run, why not all? I was able to reproduce these errors, mbed export -m NUCLEO_F412ZG -i uvision6 and get lot of errors coming from traits file.

the uvision config has standard set gnu++11.

[kjbracey-arm]

Yes, this is the issue described in the commit message of https://github.com/ARMmbed/mbed-os/commit/85041025cce45ac316e49212d3298ed21d8bb160 coming back and biting us.

Not sure how to make further progress here - we didn't manage to figure out fully what to do in #10427. I see there is µVision 5.28a now - probably too much to hope it's received an update for this, but I'll check.

[chrissnow]

here's my options in 5.27

using GNU11 and C++14 seems to work, I've not thoroughly tested it though.

[kjbracey-arm]

That immediately makes me wonder whether "C++14" is actually "gnu++14". I wouldn't have expected non-GNU mode to work - I thought our code base relied on GNU extensions.

I don't recall whether I actually double-checked the behaviour of that option at the time.

[kjbracey-arm]

Aha, 5.28a has updated this, despite no mention in the release notes. That now has
"C++14", "gnu++14", "c++17 (community)", "gnu++17 (community)".

So I guess I can update to do a 5.28a-compatible export.

[0xc0170]

Aha, 5.28a has updated this, despite no mention in the release notes.

Not only us leave some important things out of release notes 🙄