[PATCH] D71451: Support to emit extern variables debuginfo with "-fstandalone-debug"

[Jaydeep Chauhan via Phabricator via cfe-commits]

Jac1494 added a comment.

>> I'd be curious to the answer to David's questions. If the size increase is because of unused extern variables coming in from libc or something then it doesn't seem worth the cost.

For above case clang size is increase because ,it is difference between clang build without "-fstandalone-debug" option and clang build with "-fstandalone-debug"  option and both build contain change D71451 <https://reviews.llvm.org/D71451> and D71599 <https://reviews.llvm.org/D71599> . So for clang build with "-fstandalone-debug"  option size will be more because it will add debuginfo.

And to check impact of my change on clang i have build clang with and without D71451 <https://reviews.llvm.org/D71451> and D71599 <https://reviews.llvm.org/D71599> change(testcases are not included).

Size of clang without D71451 and D71599 change and with option "-fstandalone-debug":-
=====================================================================================

…
.comment                     159         0
.debug_str               3994952         0
.debug_loc                   941         0
.debug_abbrev              12754         0
.debug_info              2223641         0
.debug_ranges              46592         0
.debug_line               153901         0
.note.gnu.gold-version        28         0
Total                    6827932

Size of clang with D71451 and D71599 change and with option  "-fstandalone-debug":-
===================================================================================

…
.comment                     159         0
.debug_str               3994894         0
.debug_loc                   941         0
.debug_abbrev              12746         0
.debug_info              2223617         0
.debug_ranges              46592         0
.debug_line               153865         0
.note.gnu.gold-version        28         0
Total                    6827806

Size of clang with D71451 <https://reviews.llvm.org/D71451> and D71599 <https://reviews.llvm.org/D71599> is reduced.

This results are with latest source and with self-host build of clang. First I have build clang with Release mode and using that clang I have build clang with debug mode with below options

“cmake -DLLVM_ENABLE_PROJECTS=clang -DCMAKE_BUILD_TYPE=Debug -DCMAKE_C_COMPILER=$(which clang) -DCMAKE_CXX_COMPILER=$(which clang++) -DLLVM_TARGETS_TO_BUILD="X86" -DBUILD_SHARED_LIBS=On  -DCMAKE_CXX_FLAGS="-fstandalone-debug"   -DCMAKE_C_FLAGS="-fstandalone-debug"  -DCMAKE_INSTALL_PREFIX=/home/bft/Jaydeep/latest_llvm/llvm-project/install_withhstandalone ../llvm”


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D71451/new/

https://reviews.llvm.org/D71451