[gcc r14-7188] varasm: Fix up process_pending_assemble_externals [PR113182]

[Jakub Jelinek]

https://gcc.gnu.org/g:c05beab4ae240a593299c08ef8c775d91187a141

commit r14-7188-gc05beab4ae240a593299c08ef8c775d91187a141
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Fri Jan 12 13:58:07 2024 +0100

    varasm: Fix up process_pending_assemble_externals [PR113182]
    
    John reported that on HP-UX we no longer emit needed external libcalls.
    
    The problem is that we didn't strip name encoding when looking up
    the identifiers in assemble_external_libcall and
    process_pending_assemble_externals, while
    assemble_name_resolve does that:
      const char *real_name = targetm.strip_name_encoding (name);
      tree id = maybe_get_identifier (real_name);
    
      if (id)
        {
    ...
          mark_referenced (id);
    The intention is that assemble_external_libcall ensures the IDENTIFIER
    exists for the external libcall, then for actually emitted calls
    assemble_name_resolve sees those IDENTIFIERS and sets TREE_SYMBOL_REFERENCED
    on them and finally process_pending_assemble_externals looks the
    IDENTIFIER up again and checks its TREE_SYMBOL_REFERENCED.
    
    But without the strip_name_encoding call, they can look up different
    identifiers and those are likely never used.
    
    In the PR, John was discussing whether get_identifier or
    maybe_get_identifier should be used, I believe in assemble_external_libcall
    we definitely want to use get_identifier, we need an IDENTIFIER allocated
    so that it can be actually tracked, in process_pending_assemble_externals
    it doesn't matter, the IDENTIFIER should be already created.
    
    2024-01-12  John David Anglin  <danglin@gcc.gnu.org>
                Jakub Jelinek  <jakub@redhat.com>
    
            PR middle-end/113182
            * varasm.cc (process_pending_assemble_externals,
            assemble_external_libcall): Use targetm.strip_name_encoding
            before calling get_identifier.

Diff:
---
 gcc/varasm.cc | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/gcc/varasm.cc b/gcc/varasm.cc
index 2b633822434..d2c879b7da4 100644
--- a/gcc/varasm.cc
+++ b/gcc/varasm.cc
@@ -2552,7 +2552,8 @@ process_pending_assemble_externals (void)
   for (rtx list = pending_libcall_symbols; list; list = XEXP (list, 1))
     {
       rtx symbol = XEXP (list, 0);
-      tree id = get_identifier (XSTR (symbol, 0));
+      const char *name = targetm.strip_name_encoding (XSTR (symbol, 0));
+      tree id = get_identifier (name);
       if (TREE_SYMBOL_REFERENCED (id))
 	targetm.asm_out.external_libcall (symbol);
     }
@@ -2640,7 +2641,8 @@ assemble_external_libcall (rtx fun)
          reference to it will mark its tree node as referenced, via
          assemble_name_resolve.  These are eventually emitted, if
          used, in process_pending_assemble_externals. */
-      get_identifier (XSTR (fun, 0));
+      const char *name = targetm.strip_name_encoding (XSTR (fun, 0));
+      get_identifier (name);
       pending_libcall_symbols = gen_rtx_EXPR_LIST (VOIDmode, fun,
 						   pending_libcall_symbols);
     }