Merge r340386 into the 7.0 branch

[nemanjai]

Bugzilla Link	39173
Resolution	FIXED
Resolved on	Dec 06, 2018 16:15
Version	trunk
OS	All
Blocks	#38454
CC	@tstellar
Fixed by commit(s)	r340386 r344190 r348554

Extended Description

Without this patch, clang cannot be used as the build compiler for ToT clang/llvm with shared libraries due to failures in LIT tests with the built compiler. We need this merged into 7.0.1 so that we can use that as the build compiler.

[nemanjai]

assigned to @tstellar

[tstellar]

Hi Richard,

Is this OK to merge?

https://reviews.llvm.org/rL340386

[zygoloid]

This change caused a regression that was fixed in r344190. That's been in for only 12 days now, so taking both changes feels a little risky to me for a subtle linkage-level change like this.

Maybe we should wait for 7.0.2 and then take both changes if there have been no further problems reported? I'd like to get this fix merged to the branch, but this isn't fixing a regression -- we've always got the behavior for -fvisibility-inlines-hidden wrong.

[tstellar]

There likely won't be a 7.0.2 release. Let's revisit this closer to the 7.0.1 merge deadline when this commit has had a little more time in the master branch.

[nemanjai]

Hi Richard, Tom,

Sorry about the delay in responding to this but I am really hoping we can merge this (and the related commit that fixes the regression).

I understand that what the commit fixes isn't a regression, but the net result is that we can't use the 7.0 compiler to build trunk with shared libraries. Previously, there was nothing in trunk that exposed this issue so we didn't know about it. But now that we can't build a functioning clang/llvm trunk with 7.0 (whereas we could build previous versions of trunk with the N-1 compiler) it almost looks like a regression to the user. Internally, we use version N-1 release to build version N (trunk). Previously this wasn't a problem. Now it is.

Would you be willing to merge these in since the fix has been in trunk now for over a month?

[tstellar]

Hi Richard,

Have there been any more issues discovered with these patches? How do you feel about merging these now?

[zygoloid]

I think it's OK to take r340386 and r344190 now (plus the documentation fix in r337505 if that didn't make the branch cut). We've had enough time to find problems.

[tstellar]

Merged: r348554