Prevent mixups of IDENTIFIER_TRANSPARENT_ALIAS and IDENTIFIER_INTERNAL_P better [PR120855]

The assertion failure on ASM_OUTPUT_WEAKREF targets since my r16-1738
was caused because the 'TREE_CHAIN (id)' check in assemble_name_resolve
no longer implies that ID is a transparent alias, since internal
identifiers can have a TREE_CHAIN as well.

I still don't think it's possible for a transparent alias to be an
internal identifier in the sense added, so this patch simply constrains
the assertion better so that it doesn't fail spuriously.  I also added a
couple of other assertions to help validate this assumption.

	PR middle-end/120855

gcc/ChangeLog:

	* cgraphunit.cc (symbol_table::compile): Assert a transparent
	alias is not an internal identifier.
	* symtab.cc (symbol_table::change_decl_assembler_name):
	Likewise.
	* varasm.cc (assemble_name_resolve): Check for
	IDENTIFIER_TRANSPARENT_ALIAS instead of just TREE_CHAIN.

Signed-off-by: Nathaniel Shead <[email protected]>
Reviewed-by: Jason Merrill <[email protected]>

Author: wreien

gcc/cgraphunit.cc

@@ -2400,9 +2400,10 @@ symbol_table::compile (void)
     if (node->alias
 	&& lookup_attribute ("weakref", DECL_ATTRIBUTES (node->decl)))
       {
-	IDENTIFIER_TRANSPARENT_ALIAS
-	   (DECL_ASSEMBLER_NAME (node->decl)) = 1;
-	TREE_CHAIN (DECL_ASSEMBLER_NAME (node->decl))
+	tree id = DECL_ASSEMBLER_NAME (node->decl);
+	gcc_assert (!IDENTIFIER_INTERNAL_P (id));
+	IDENTIFIER_TRANSPARENT_ALIAS (id) = 1;
+	TREE_CHAIN (id)
 	   = (node->alias_target ? node->alias_target
 	      : DECL_ASSEMBLER_NAME (node->get_alias_target ()->decl));
       }

gcc/symtab.cc

@@ -305,6 +305,7 @@ symbol_table::change_decl_assembler_name (tree decl, tree name)
       SET_DECL_ASSEMBLER_NAME (decl, name);
       if (alias)
 	{
+	  gcc_assert (!IDENTIFIER_INTERNAL_P (name));
 	  IDENTIFIER_TRANSPARENT_ALIAS (name) = 1;
 	  TREE_CHAIN (name) = alias;
 	}

gcc/varasm.cc

@@ -2908,7 +2908,7 @@ assemble_name_resolve (const char *name)
       ultimate_transparent_alias_target (&id);
       if (id != id_orig)
 	name = IDENTIFIER_POINTER (id);
-      gcc_assert (! TREE_CHAIN (id));
+      gcc_assert (!IDENTIFIER_TRANSPARENT_ALIAS (id));
     }
 
   return name;