commit 16f4406f4e8fcc977334a1a7d4cc6ec302421cc8
author Fangrui Song <maskray@google.com> Mon Oct 22 23:43:53 2018 +0000
committer Fangrui Song <maskray@google.com> Mon Oct 22 23:43:53 2018 +0000
tree 46f4a8da36f88e46666410627685fed051deae9e
parent 98c7ed52b8b10e4941a4feba9f2a820ec28b96d3

[ELF] Don't warn on two legitimate cases when reading .llvm.call-graph-profile

Summary:
Before, superfluous warnings were emitted for the following two cases:

1) When from symbol was in a discarded section.
  The profile should be thought of as affiliated to the section.
  It makes sense to ignore the profile if the section is discarded.

2) When to symbol was in a shared object.
  The object file containing the profile may not know about the to
  symbol, which can reside in another object file (useful profile) or a
  shared object (not useful as symbols in the shared object are fixed
  and unorderable). It makes sense to ignore the profile from the object
  file.

  Note, the warning when to symbol was undefined was suppressed in
  D53044, which is still useful for --symbol-ordering-file=

This patch silences the warnings. The check is actually more relaxed (no
warnings if either From or To is not Defined) for simplicity and I don't
see a compelling reason to warn on more cases.

Reviewers: ruiu, davidxl, espindola, Bigcheese

Reviewed By: ruiu

Subscribers: emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D53470

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@344974 91177308-0d34-0410-b5e6-96231b3b80d8