Fix LTO issue with minimal-printf

[jamesbeyond]

Summary of changes

Minimal-printf is enabled by default now.
However, LTO have some issues when build with minimal-printf.
This PR update lto profile including all printf related wrap functions.
So the Nightly LTO build job will be passed

Impact of changes

Migration actions required

Documentation

Not Requed

Pull request type

[x] Patch update (Bug fix / Target update / Docs update / Test update / Refactor)
[] Feature update (New feature / Functionality change / New API)
[] Major update (Breaking change E.g. Return code change / API behaviour change)

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Test results

[] No Tests required for this change (E.g docs only update)
[x] Covered by existing mbed-os tests (Greentea or Unittest)
[] Tests / results supplied as part of this PR

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Reviewers

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[ciarmcom]

@jamesbeyond, thank you for your changes.
@ARMmbed/mbed-os-tools @ARMmbed/mbed-os-maintainers please review.

[0xc0170]

So the Nightly LTO build job will be passed

This is one of the things for me to look at today, if this fixes it, nightly build can be green again 💯

[0xc0170]

CI started

[mbed-ci]

Test run: FAILED

Summary: 2 of 6 test jobs failed
Build number : 1
Build artifacts

Failed test jobs:

• jenkins-ci/mbed-os-ci_cloud-client-pytest
• jenkins-ci/mbed-os-ci_greentea-test

[jamesbeyond]

Seems the failures are not related, maybe due to a flaky target in CI?

[0xc0170]

tests restarted (if the target is again io serial, we will request test to restart the target or remove)

[mark-edgeworth]

Needs testing properly

[jamesbeyond]

Needs testing properly

Yes, they have been tested locally, everything is passed as expected.
What I mean in my last comment was: I knew for sure those linker options are needed when LTO is enabled.

But what I don't know is when LTO is not in use, still apply those option, is there any side effect? reading gcc docs didn't give very clear answers. That why I suggest leaving these options in this JSON file. rather than put into the build scripts, So these options will only get applied when LTO in use

[0xc0170]

Client restarted

[0xc0170]

But what I don't know is when LTO is not in use, still apply those option, is there any side effect? reading gcc docs didn't give very clear answers. That why I suggest leaving these options in this JSON file. rather than put into the build scripts, So these options will only get applied when LTO in use

I found a note "Only undefined references are replaced by the linker." in https://sourceware.org/binutils/docs/ld/Options.html. If there are no undefined ref, nothing to replace. Is that case when minimal printf not enabled?

[jamesbeyond]

I found a note "Only undefined references are replaced by the linker." in https://sourceware.org/binutils/docs/ld/Options.html. If there are no undefined ref, nothing to replace. Is that case when minimal printf not enabled?

if minimal-printf is not enabled, then we are not going to give --wrap option to those printf() functions, hence all the undefined symbol will be resolved to stand library. so all the __wrap_printf symbols will not be used anyway

[0xc0170]

@evedon @mark-edgeworth All good here to merge it today?

[mark-edgeworth]

ok with me.