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概要[]
4861 /* Emit an assembler directive to make the symbol for DECL an alias to 4862 the symbol for TARGET. */
引数[]
実装[]
4864 void
4865 assemble_alias (tree decl, tree target)
4866 {
4867 tree target_decl;
4868 bool is_weakref = false;
4869
4870 if (lookup_attribute ("weakref", DECL_ATTRIBUTES (decl)))
4871 {
4872 tree alias = DECL_ASSEMBLER_NAME (decl);
4873
4874 is_weakref = true;
4875
4876 ultimate_transparent_alias_target (&target);
4877
4878 if (alias == target)
4879 error ("weakref %q+D ultimately targets itself", decl);
4880 else
4881 {
4882 #ifndef ASM_OUTPUT_WEAKREF
4883 IDENTIFIER_TRANSPARENT_ALIAS (alias) = 1;
4884 TREE_CHAIN (alias) = target;
4885 #endif
4886 }
4887 }
4888 else
4889 {
4890 #if !defined (ASM_OUTPUT_DEF)
4891 # if !defined(ASM_OUTPUT_WEAK_ALIAS) && !defined (ASM_WEAKEN_DECL)
4892 error ("%Jalias definitions not supported in this configuration", decl);
4893 return;
4894 # else
4895 if (!DECL_WEAK (decl))
4896 {
4897 error ("%Jonly weak aliases are supported in this configuration", decl);
4898 return;
4899 }
4900 # endif
4901 #endif
4902 }
4903
4904 /* We must force creation of DECL_RTL for debug info generation, even though
4905 we don't use it here. */
4906 make_decl_rtl (decl);
4907 TREE_USED (decl) = 1;
4908
4909 /* A quirk of the initial implementation of aliases required that the user
4910 add "extern" to all of them. Which is silly, but now historical. Do
4911 note that the symbol is in fact locally defined. */
4912 if (! is_weakref)
4913 DECL_EXTERNAL (decl) = 0;
4914
4915 /* Allow aliases to aliases. */
4916 if (TREE_CODE (decl) == FUNCTION_DECL)
4917 cgraph_node (decl)->alias = true;
4918 else
4919 cgraph_varpool_node (decl)->alias = true;
4920
4921 /* If the target has already been emitted, we don't have to queue the
4922 alias. This saves a tad o memory. */
4923 target_decl = find_decl_and_mark_needed (decl, target);
4924 if (target_decl && TREE_ASM_WRITTEN (target_decl))
4925 do_assemble_alias (decl, target);
4926 else
4927 {
4928 alias_pair *p = VEC_safe_push (alias_pair, gc, alias_pairs, NULL);
4929 p->decl = decl;
4930 p->target = target;
4931 }
4932 }
4933
4934 /* Emit an assembler directive to set symbol for DECL visibility to
4935 the visibility type VIS, which must not be VISIBILITY_DEFAULT. */
4936
4937 void
4938 default_assemble_visibility (tree decl, int vis)
4939 {
4940 static const char * const visibility_types[] = {
4941 NULL, "internal", "hidden", "protected"
4942 };
4943
4944 const char *name, *type;
4945
4946 name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
4947 type = visibility_types[vis];
4948
4949 #ifdef HAVE_GAS_HIDDEN
4950 fprintf (asm_out_file, "\t.%s\t", type);
4951 assemble_name (asm_out_file, name);
4952 fprintf (asm_out_file, "\n");
4953 #else
4954 warning (OPT_Wattributes, "visibility attribute not supported "
4955 "in this configuration; ignored");
4956 #endif
4957 }