c-common.h (c_language_kind): New type.

	* c-common.h (c_language_kind): New type.
	(c_language): New variab.e
	* c-common.c (lang_get_alias_set): Don't put structures in
	non-zero alias sets in C++.
	* c-decl.c (c_language): Define it.
	* c-lex.c (doing_objc_thang): Remove.
	* c-tree.h (doing_objc_thang): Make it a macro.
	* objc/objc-act.c (lang_decode_option): Set c_language, not
	doing_objc_thang.

	* decl2.c (c_language): Define.

From-SVN: r34439

gcc/ChangeLog

+2000-06-06  Mark Mitchell  <mark@codesourcery.com>
+
+	* c-common.h (c_language_kind): New type.
+	(c_language): New variab.e
+	* c-common.c (lang_get_alias_set): Don't put structures in
+	non-zero alias sets in C++.
+	* c-decl.c (c_language): Define it.
+	* c-lex.c (doing_objc_thang): Remove.
+	* c-tree.h (doing_objc_thang): Make it a macro.
+	* objc/objc-act.c (lang_decode_option): Set c_language, not
+	doing_objc_thang. 
+	
 2000-06-06  Gabriel Dos Reis  <gdr@codesourcery.com>
 
 	* diagnostic.c (output_maximum_width): Remove.

gcc/c-common.c

@@ -3338,6 +3338,10 @@ lang_get_alias_set (t)
       if (t1 != t)
 	return get_alias_set (t1);
     }
+  /* It's not yet safe to use alias sets for classes in C++ because
+     the TYPE_FIELDs list for a class doesn't mention base classes.  */
+  else if (c_language == clk_cplusplus && AGGREGATE_TYPE_P (t));
+    return 0;
 
   return -1;
 }

gcc/c-common.h

@@ -56,6 +56,19 @@ enum c_tree_index
 
 extern tree c_global_trees[CTI_MAX];
 
+typedef enum c_language_kind
+{
+  clk_c,           /* A dialect of C: K&R C, ANSI/ISO C89, C2000,
+		       etc. */
+  clk_cplusplus,   /* ANSI/ISO C++ */
+  clk_objective_c  /* Objective C */
+} 
+c_language_kind;
+
+/* The variant of the C language being processed.  Each C language
+   front-end defines this variable.  */
+extern c_language_kind c_language;
+
 #define wchar_type_node			c_global_trees[CTI_WCHAR_TYPE]
 #define signed_wchar_type_node		c_global_trees[CTI_SIGNED_WCHAR_TYPE]
 #define unsigned_wchar_type_node	c_global_trees[CTI_UNSIGNED_WCHAR_TYPE]

gcc/c-decl.c

@@ -454,6 +454,10 @@ int warn_float_equal = 0;
 
 int warn_multichar = 1;
 
+/* The variant of the C language being processed.  */
+
+c_language_kind c_language = clk_c;
+
 /* Nonzero means `$' can be in an identifier.  */
 
 #ifndef DOLLARS_IN_IDENTIFIERS

gcc/c-lex.c

@@ -132,10 +132,6 @@ int linemode;
    used in a context which makes it a reference to a variable.  */
 tree lastiddecl;
 
-/* Nonzero enables objc features.  */
-
-int doing_objc_thang;
-
 extern int yydebug;
 
 /* File used for outputting assembler code.  */

gcc/c-tree.h

@@ -446,7 +446,8 @@ extern int system_header_p;
 
 /* Nonzero enables objc features.  */
 
-extern int doing_objc_thang;
+#define doing_objc_thang \
+  (c_language == clk_objective_c)
 
 /* In c-decl.c */
 extern void finish_incomplete_decl PARAMS ((tree));

gcc/cp/ChangeLog

+2000-06-06  Mark Mitchell  <mark@codesourcery.com>
+
+	* decl2.c (c_language): Define.
+
 2000-06-06  Gabriel Dos Reis  <gdr@codesourcery.com>
 
 	* lex.c (lang_init_options): Tweak.

gcc/cp/decl2.c

@@ -501,6 +501,10 @@ int flag_enforce_eh_specs = 1;
 
 void (*back_end_hook) PARAMS ((tree));
 
+/* The variant of the C language being processed.  */
+
+c_language_kind c_language = clk_cplusplus;
+
 /* Table of language-dependent -f options.
    STRING is the option name.  VARIABLE is the address of the variable.
    ON_VALUE is the value to store in VARIABLE

gcc/objc/objc-act.c

@@ -798,7 +798,7 @@ lang_decode_option (argc, argv)
 {
   const char *p = argv[0];
   if (!strcmp (p, "-lang-objc"))
-    doing_objc_thang = 1;
+    c_language = clk_objective_c;
   else if (!strcmp (p, "-gen-decls"))
     flag_gen_declaration = 1;
   else if (!strcmp (p, "-Wselector"))