Commit Graph

8 Commits

Author SHA1 Message Date
Fangrui Song 11ca54f49c [ELF] Don't warn on undefined symbols if UnresolvedPolicy::Ignore is used
Summary:
Add a condition UnresolvedPolicy::Ignore to elf::warnUnorderedSymbol to suppress Sym->isUndefined() warnings from both

1) --symbol-ordering-file=
2) .llvm.call-graph-profile

If --unresolved-symbols=ignore-all is used,

  no "undefined symbol" error/warning is emitted. It makes sense to not warn unorderable symbols.

Otherwise,

  If an executable is linked, the default policy UnresolvedPolicy::ErrorOrWarn will issue a "undefined symbol" error. The unorderable symbol warning is redundant.

  If a shared object is linked, it is possible that only part of object files are used and some symbols are left undefined. The warning is not very necessary.
    In particular for .llvm.call-graph-profile, when linking a shared object, a call graph profile may contain undefined symbols. This case generated a warning before but it will be suppressed by this patch.

Reviewers: ruiu, davidxl, espindola

Reviewed By: ruiu

Subscribers: grimar, emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D53044

llvm-svn: 344195
2018-10-10 22:48:57 +00:00
Rafael Espindola 262589db70 Don't warn on ICFed symbols, warn on synthetic ones.
Based on a patch for the ICF warning by Rui.

llvm-svn: 329757
2018-04-10 21:13:52 +00:00
Rafael Espindola 3bd98b1031 Change which file we print when a symbol cannot be ordered.
Currently there are a few odd things about the warning about symbols
that cannot be ordered. This patch fixes:

* When there is an undefined symbol that resolves to a shared file, we
  were printing the location of the undefined reference.

* If there are multiple comdats, we were reporting them all.

llvm-svn: 329371
2018-04-06 03:36:19 +00:00
Rui Ueyama b0084a0eee Revert r326911: Improve --warn-symbol-ordering.
This reverts commit r326911 because it was committed by accident.

llvm-svn: 326914
2018-03-07 17:24:46 +00:00
Rui Ueyama ebfab927d9 Improve --warn-symbol-ordering.
Summary:
I originally tried to simplify code and then noticed that lld doesn't
do what it tells to the user by warn(). It says "unable to order
discarded symbol" but it actually can for sections eliminated by ICF.
With this patch, lld doesn't sort such sections.

Reviewers: jhenderson, rafael

Subscribers: emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D44180

llvm-svn: 326911
2018-03-07 17:15:06 +00:00
Rui Ueyama 9f0c36e7a9 Split long lines in a test file.
llvm-svn: 326850
2018-03-07 00:07:26 +00:00
James Henderson 149343c374 [ELF] Extend symbol-order-warnings test case for ICF
Reviewed by: rafael

Differential Revision: https://reviews.llvm.org/D43336

There is some discussion as to the exact behaviour of combining ICF and
--symbol-ordering-file, but it seems beneficial to warn when attempting
to order the removed symbol regardless of the preferred approach.

llvm-svn: 325333
2018-02-16 10:49:57 +00:00
James Henderson de300e66bb [ELF] Add warnings for various symbols that cannot be ordered
There are a number of different situations when symbols are requested
to be ordered in the --symbol-ordering-file that cannot be ordered for
some reason. To assist with identifying these symbols, and either
tidying up the order file, or the inputs, a number of warnings have
been added. As some users may find these warnings unhelpful, due to how
they use the symbol ordering file, a switch has also been added to
disable these warnings.

The cases where we now warn are:

 * Entries in the order file that don't correspond to any symbol in the input
 * Undefined symbols
 * Absolute symbols
 * Symbols imported from shared objects
 * Symbols that are discarded, due to e.g. --gc-sections or /DISCARD/ linker script sections
 * Multiple of the same entry in the order file

Reviewed by: rafael, ruiu

Differential Revision: https://reviews.llvm.org/D42475

llvm-svn: 325125
2018-02-14 13:36:22 +00:00