gas: Extend .symver directive

Extend .symver directive to update visibility of the original symbol and
assign one original symbol to different versioned symbols:

  .symver foo, foo@VERS_1, local    # Change foo to a local symbol.
  .symver foo, foo@VERS_2, hidden   # Change foo to a hidden symbol.
  .symver foo, foo@@VERS_3, remove  # Remove foo from symbol table.
  .symver foo, bar@V1               # Assign foo to bar@V1 and baz@V2.
  .symver foo, baz@V2

	PR gas/23840
	PR gas/25295
	* NEWS: Mention .symver extension.
	* config/obj-elf.c (obj_elf_find_and_add_versioned_name): New
	function.
	(obj_elf_symver): Call obj_elf_find_and_add_versioned_name to
	add a version name.  Add local, hidden and remove visibility
	support.
	(elf_frob_symbol): Handle the list of version names.  Update the
	original symbol to local, hidden or remove it from the symbol
	table.
	(elf_frob_file_before_adjust): Handle the list of version names.
	* config/obj-elf.h (elf_visibility): New.
	(elf_versioned_name_list): Likewise.
	(elf_obj_sy): Change local to bitfield. Add rename, bad_version
	and visibility.  Change versioned_name pointer to struct
	elf_versioned_name_list.
	* doc/as.texi: Update .symver directive.
	* testsuite/gas/symver/symver.exp: Run all *.d tests.  Add more
	error checking tests.
	* testsuite/gas/symver/symver6.d: New file.
	* testsuite/gas/symver/symver7.d: Likewise.
	* testsuite/gas/symver/symver7.s: Likewise.
	* testsuite/gas/symver/symver8.d: Likewise.
	* testsuite/gas/symver/symver8.s: Likewise.
	* testsuite/gas/symver/symver9.s: Likewise.
	* testsuite/gas/symver/symver9a.d: Likewise.
	* testsuite/gas/symver/symver9b.d: Likewise.
	* testsuite/gas/symver/symver10.s: Likewise.
	* testsuite/gas/symver/symver10a.d: Likewise.
	* testsuite/gas/symver/symver10b.d: Likewise.
	* testsuite/gas/symver/symver11.d: Likewise.
	* testsuite/gas/symver/symver11.s: Likewise.
	* testsuite/gas/symver/symver12.d: Likewise.
	* testsuite/gas/symver/symver12.s: Likewise.
	* testsuite/gas/symver/symver13.d: Likewise.
	* testsuite/gas/symver/symver13.s: Likewise.
	* testsuite/gas/symver/symver14.d: Likewise.
	* testsuite/gas/symver/symver14.l: Likewise.
	* testsuite/gas/symver/symver15.d: Likewise.
	* testsuite/gas/symver/symver15.l: Likewise.
	* testsuite/gas/symver/symver6.l: Removed.
	* testsuite/gas/symver/symver6.s: Updated.

1 files changed, 12 insertions, 4 deletions

diff --git a/gas/doc/as.texi b/gas/doc/as.texi
index 0a6727e..8669879 100644
--- a/gas/doc/as.texi
+++ b/gas/doc/as.texi
@@ -4509,7 +4509,7 @@ Some machine configurations provide additional directives.
 * Struct::			@code{.struct @var{expression}}
 @ifset ELF
 * SubSection::                  @code{.subsection}
-* Symver::                      @code{.symver @var{name},@var{name2@@nodename}}
+* Symver::                      @code{.symver @var{name},@var{name2@@nodename}[,@var{visibility}]}
 @end ifset
 
 @ifset COFF
@@ -7112,9 +7112,9 @@ shared library.
 
 For ELF targets, the @code{.symver} directive can be used like this:
 @smallexample
-.symver @var{name}, @var{name2@@nodename}
+.symver @var{name}, @var{name2@@nodename}[ ,@var{visibility}]
 @end smallexample
-If the symbol @var{name} is defined within the file
+If the original symbol @var{name} is defined within the file
 being assembled, the @code{.symver} directive effectively creates a symbol
 alias with the name @var{name2@@nodename}, and in fact the main reason that we
 just don't try and create a regular alias is that the @var{@@} character isn't
@@ -7127,7 +7127,15 @@ function is being mentioned.  The @var{nodename} portion of the alias should be
 the name of a node specified in the version script supplied to the linker when
 building a shared library.  If you are attempting to override a versioned
 symbol from a shared library, then @var{nodename} should correspond to the
-nodename of the symbol you are trying to override.
+nodename of the symbol you are trying to override.  The optional argument
+@var{visibility} updates the visibility of the original symbol.  The valid
+visibilities are @code{local}, @code {hidden}, and @code {remove}.  The
+@code{local} visibility makes the original symbol a local symbol
+(@pxref{Local}).  The @code{hidden} visibility sets the visibility of the
+original symbol to @code{hidden} (@pxref{Hidden}).  The @code{remove}
+visibility removes the original symbol from the symbol table if it isn't
+used in relocation.  If visibility isn't specified, the original symbol
+is unchanged.
 
 If the symbol @var{name} is not defined within the file being assembled, all
 references to @var{name} will be changed to @var{name2@@nodename}.  If no