[PATCH] ld: Keep indirect symbol from IR if referenced from shared object

[H.J. Lu]

On Fri, Feb 11, 2022 at 3:19 PM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> Don't change indirect symbol defined in IR to undefined if it is
> referenced from shared object.
>
> bfd/
>
>         PR ld/28879
>         * elflink.c (_bfd_elf_merge_symbol): Don't change indirect
>         symbol defined in IR to undefined if it is referenced from
>         shared object.
>
> ld/
>
>         PR ld/28879
>         * testsuite/ld-plugin/lto.exp: Run PR ld/28879 tests.
>         * testsuite/ld-plugin/pr28879a.cc: New file.
>         * testsuite/ld-plugin/pr28879b.cc: Likewise.
> ---
>  bfd/elflink.c                      |  5 ++---
>  ld/testsuite/ld-plugin/lto.exp     | 26 ++++++++++++++++++++++++++
>  ld/testsuite/ld-plugin/pr28879a.cc |  7 +++++++
>  ld/testsuite/ld-plugin/pr28879b.cc |  8 ++++++++
>  4 files changed, 43 insertions(+), 3 deletions(-)
>  create mode 100644 ld/testsuite/ld-plugin/pr28879a.cc
>  create mode 100644 ld/testsuite/ld-plugin/pr28879b.cc
>
> diff --git a/bfd/elflink.c b/bfd/elflink.c
> index 6fa18d92007..f8521426cad 100644
> --- a/bfd/elflink.c
> +++ b/bfd/elflink.c
> @@ -1294,9 +1294,8 @@ _bfd_elf_merge_symbol (bfd *abfd,
>           h->root.non_ir_ref_dynamic = true;
>           hi->root.non_ir_ref_dynamic = true;
>         }
> -
> -      if ((oldbfd->flags & BFD_PLUGIN) != 0
> -         && hi->root.type == bfd_link_hash_indirect)
> +      else if ((oldbfd->flags & BFD_PLUGIN) != 0
> +              && hi->root.type == bfd_link_hash_indirect)
>         {
>           /* Change indirect symbol from IR to undefined.  */
>           hi->root.type = bfd_link_hash_undefined;
> diff --git a/ld/testsuite/ld-plugin/lto.exp b/ld/testsuite/ld-plugin/lto.exp
> index a70a84562b8..64b880265ee 100644
> --- a/ld/testsuite/ld-plugin/lto.exp
> +++ b/ld/testsuite/ld-plugin/lto.exp
> @@ -471,6 +471,32 @@ set lto_link_elf_tests [list \
>    [list {pr27441c.so} \
>     {-shared -fPIC -Wl,--as-needed tmpdir/pr27441c.o tmpdir/pr27441b.so tmpdir/pr27441a.so} {-fPIC} \
>     {dummy.c} {{readelf {-dW} pr27441c.d}} {pr27441c.so}] \
> +  [list \
> +   "Build libpr28879a.so" \
> +   "-shared" \
> +   "-O0 -fpic" \
> +   {pr28879a.cc} \
> +   {} \
> +   "libpr28879a.so" \
> +   "c++" \
> +  ] \
> +  [list \
> +   "Build libpr28879b.so" \
> +   "-shared -Wl,--no-as-needed tmpdir/libpr28879a.so" \
> +   "-O2 -fpic" \
> +   {dummy.c} \
> +   {} \
> +   "libpr28879b.so" \
> +  ] \
> +  [list \
> +   "Build pr28879" \
> +   "-Wl,--no-as-needed tmpdir/libpr28879b.so -Wl,-rpath-link,." \
> +   "-O0 -flto -D_GLIBCXX_ASSERTIONS" \
> +   {pr28879b.cc} \
> +   {} \
> +   "pr28879" \
> +   "c++" \
> +  ] \
>  ]
>
>  # PR 14918 checks that libgcc is not spuriously included in a shared link of
> diff --git a/ld/testsuite/ld-plugin/pr28879a.cc b/ld/testsuite/ld-plugin/pr28879a.cc
> new file mode 100644
> index 00000000000..8307a42e2fb
> --- /dev/null
> +++ b/ld/testsuite/ld-plugin/pr28879a.cc
> @@ -0,0 +1,7 @@
> +#include <string>
> +
> +void
> +func (std::string *s)
> +{
> +  delete s;
> +}
> diff --git a/ld/testsuite/ld-plugin/pr28879b.cc b/ld/testsuite/ld-plugin/pr28879b.cc
> new file mode 100644
> index 00000000000..02fc351366c
> --- /dev/null
> +++ b/ld/testsuite/ld-plugin/pr28879b.cc
> @@ -0,0 +1,8 @@
> +#include <string>
> +
> +int
> +main (void)
> +{
> +  std::string header;
> +  return 0;
> +}
> --
> 2.34.1
>

Hi Nick, Alan,

Is this OK for master and 2.38 branch?

Thanks.

-- 
H.J.