[PATCH] D123534: [dwarf] Emit a DIGlobalVariable for constant strings.

[David Blaikie via Phabricator via cfe-commits]

dblaikie added subscribers: aprantl, rnk.
dblaikie added a comment.

Tried this patch on some internal targets and metrics and it seems actually quite reasonable.

Tested with split DWARF, on Linux, with compressed debug info in .o/.dwo files, uncompressed in exe/dwp files. With -O0 and -O3, roughly speaking. Testing Clang as well as testing a large Google binary only at -O3:
Clang:
-O0:
.o: +0.44%
.dwo: +1.55%
exe: 0.65%
dwp: 1.42%
-O3:
.o: 0.90%
.dwo: 0.26%
exe: 0.33%
dwp: 0.41%

Large Google Binary -O3:
.o: 0.32%
.dwo: 0.16%
exe: 0.19%
dwp: 0.22%

These are % of total size, not % of debug info contribution - so it's growing the debug info by more than that, but the total impact doesn't seem to be too bad.

@rnk @aprantl @probinson: this looks plausible to me to take as a general change to the emitted DWARF, but I'm open to ideas/suggestions if folks find this to be too much growth for not enough benefit & that it should be behind a flag?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D123534/new/

https://reviews.llvm.org/D123534