[PATCH v3 0/4] PE-COFF weak external fixes

[Peter Damianov]

After I sent my last patch series, I was reminded of:
https://gcc.gnu.org/PR124263 and
https://github.com/skeeto/w64devkit/issues/393 , which looked 
related and like this patch could fix them. It turned out to be
a related issue but with archives instead. This submission adds
an extra patch to fix that reported issue and adds extra tests
covering that issue. I tested that it also fixes the upstream GCC
issue.

Changes from v2:

  * Add a new BFD archive fix for GCC PR124263.  PE weak externals are
    canonicalized as undefined BFD symbols even when their aux entry
    names a real fallback definition.  The archive map now advertises
    those public weak names, while still excluding weak declarations
    whose fallback is the absolute-zero null symbol.
  * Avoid extracting the same archive member again during repeated
    archive searches once a PE weak external resolves through a real
    fallback definition.
  * Extend the testsuite patch with an archive regression test covering
    the positive real-fallback armap case, the negative null-fallback
    declaration case, and the duplicate archive search case.

The first two patches are unchanged from v2.  The new archive fix is
patch 3, and the testsuite patch is modified with extra tests exercising
the fix.

Peter Damianov (4):
  PE-COFF: Fix weak external symbol resolution when strong undef is seen
    first
  PE-COFF: Prefer weak external with defined fallback over null fallback
  bfd: Handle PE weak externals with real fallbacks in archives
  ld/testsuite: Add comprehensive PE COFF weak external tests

 bfd/archive.c                                 |  22 ++-
 bfd/coff-bfd.c                                |  47 +++++
 bfd/coff-bfd.h                                |   3 +
 bfd/cofflink.c                                | 183 ++++++++++++++++--
 ld/testsuite/ld-pe/pe-compile.exp             | 167 ++++++++++++++++
 .../ld-pe/weak-ext-add1-weak-chained.c        |  13 ++
 ld/testsuite/ld-pe/weak-ext-add2.c            |   8 +
 ld/testsuite/ld-pe/weak-ext-dummy.c           |   5 +
 ld/testsuite/ld-pe/weak-ext-expected1.c       |   1 +
 .../ld-pe/weak-ext-expected3-add1-weak.c      |   9 +
 ld/testsuite/ld-pe/weak-ext-expected3.c       |   1 +
 ld/testsuite/ld-pe/weak-ext-expected5.c       |   1 +
 ld/testsuite/ld-pe/weak-ext-main-weak-def.c   |  26 +++
 ld/testsuite/ld-pe/weak-ext-main-weak.c       |  22 +++
 ld/testsuite/ld-pe/weak-ext-main.c            |  21 ++
 15 files changed, 510 insertions(+), 19 deletions(-)
 create mode 100644 ld/testsuite/ld-pe/weak-ext-add1-weak-chained.c
 create mode 100644 ld/testsuite/ld-pe/weak-ext-add2.c
 create mode 100644 ld/testsuite/ld-pe/weak-ext-dummy.c
 create mode 100644 ld/testsuite/ld-pe/weak-ext-expected1.c
 create mode 100644 ld/testsuite/ld-pe/weak-ext-expected3-add1-weak.c
 create mode 100644 ld/testsuite/ld-pe/weak-ext-expected3.c
 create mode 100644 ld/testsuite/ld-pe/weak-ext-expected5.c
 create mode 100644 ld/testsuite/ld-pe/weak-ext-main-weak-def.c
 create mode 100644 ld/testsuite/ld-pe/weak-ext-main-weak.c
 create mode 100644 ld/testsuite/ld-pe/weak-ext-main.c

-- 
2.54.0