tree 245eb7344523d574216bb6ca7415374c3a690308
parent b58a4e226bef79a7c37b8af07910b3f97ebc88ee
author Adrian Prantl <aprantl@apple.com> 1460225422 +0000
committer Adrian Prantl <aprantl@apple.com> 1460225422 +0000

Drop debug info for DISubprograms that are not referenced by anything

This patch drops the debug info for all DISubprograms that are
(a) not attached to an llvm::Function and
(b) not indirectly reachable via inline scopes from any surviving Function and
(c) not reachable from a type (i.e.: member functions).

Background: I'm currently working on a patch to reverse the pointers
between DICompileUnit and DISubprogram (for more info check Duncan's RFC
on lazy-loading of debug info metadata
http://lists.llvm.org/pipermail/llvm-dev/2016-March/097419.html).
The idea is to remove the list of subprograms from DICompileUnit and
instead point to the owning compile unit from each DISubprogram.
After doing this all DISubprograms fulfilling the above criteria will be
implicitly dropped unless we go through an extra effort to preserve them.

http://reviews.llvm.org/D18477
<rdar://problem/25256815>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@265876 91177308-0d34-0410-b5e6-96231b3b80d8