ld: Cache and reuse the IR archive file descriptor

Linker plugin_object_p opens the IR archive for each IR archive member.
For GCC plugin, plugin_object_p closes the archive file descriptor.  But
for LLVM plugin, the archive file descriptor remains open.  If there are
3000 IR archive members, there are 3000 file descriptors for them.  We
can run out of file descriptors petty easily.

1. Add archive_plugin_fd and archive_plugin_fd_open_count to bfd so that
we can cache and reuse the IR archive file descriptor for all IR archive
members in the archive.
2. Add bfd_plugin_close_file_descriptor to properly close the IR archive
file descriptor.

bfd/

	PR ld/28040
	* archive.c (_bfd_archive_close_and_cleanup): Close the archive
	plugin file descriptor if needed.
	* bfd.c (bfd): Add archive_plugin_fd and
	archive_plugin_fd_open_count.
	* opncls.c (_bfd_new_bfd): Initialize to -1.
	* plugin.c (bfd_plugin_open_input): Cache and reuse the archive
	plugin file descriptor.
	(bfd_plugin_close_file_descriptor): New function.
	(try_claim): Call bfd_plugin_close_file_descriptor.
	* plugin.h (bfd_plugin_close_file_descriptor): New.
	* bfd-in2.h: Regenerated.

ld/

	PR ld/28040
	* plugin.c (plugin_input_file): Add ibfd.
	(release_plugin_file_descriptor): New function.
	(release_input_file): Call release_plugin_file_descriptor to
	close input->fd.
	(plugin_object_p): Call release_plugin_file_descriptor to close
	input->fd.  Also call release_plugin_file_descriptor if not
	claimed.
	* testsuite/config/default.exp (RANLIB): New.
	* testsuite/ld-plugin/lto.exp: Run ranlib test.

1 files changed, 6 insertions, 0 deletions

diff --git a/bfd/bfd.c b/bfd/bfd.c
index 6e5d339..0952aae 100644
--- a/bfd/bfd.c
+++ b/bfd/bfd.c
@@ -276,6 +276,12 @@ CODE_FRAGMENT
 .  {* The number of sections.  *}
 .  unsigned int section_count;
 .
+.  {* The archive plugin file descriptor.  *}
+.  int archive_plugin_fd;
+.
+.  {* The number of opens on the archive plugin file descriptor.  *}
+.  unsigned int archive_plugin_fd_open_count;
+.
 .  {* A field used by _bfd_generic_link_add_archive_symbols.  This will
 .     be used only for archive elements.  *}
 .  int archive_pass;