Merge debug-experience fixes into 7.0.1 branch

[jmorse]

Bugzilla Link	39691
Resolution	FIXED
Resolved on	Nov 30, 2018 09:55
Version	7.0
OS	Linux
Blocks	#38454
CC	@gregbedwell,@pogo59,@pogo59,@tstellar
Fixed by commit(s)	r344589 r348011

Extended Description

Hi, could we merge the following debug-info patches into the 7.0.1 release? They're all small-scope independent patches fixing bad debug experiences such as presenting illegal variable values or stepping onto unreachable lines.

svn bugzilla Phab-review
r345996 38952 https://reviews.llvm.org/D53992
r344589 39019 https://reviews.llvm.org/D53130
r343445 38773 https://reviews.llvm.org/D52614
r342527 38763 https://reviews.llvm.org/D51976
r345250 38762 https://reviews.llvm.org/D53287

(While the patches are independent of other changes, r345250 depends on r342527 due to the use of dropDebugUsers).

[jmorse]

assigned to @echristo

[tstellar]

Hi Eric,

Are these OK to merge?

[echristo]

Should be ok.

[jmorse]

Apologies, it looks like I didn't properly check that these apply cleanly -- as it stands, just r344589 will apply cleanly by itself, my mistake.

It's no big deal if the others are dropped, they're all small improvements.

[tstellar]

Merged: r348011