re PR c/51849 (-Wc99-compat would be considered useful)

	PR c/51849
gcc/
	* gcc/doc/invoke.texi: Document -Wc90-c99-compat.
gcc/c-family/
	* c-opts.c (sanitize_cpp_opts): Pass warn_c90_c99_compat to libcpp.
	* c.opt (Wc90-c99-compat): Add option.
gcc/c/
	* c-decl.c (build_array_declarator): Remove check for !flag_isoc99.
	Call pedwarn_c90 instead of pedwarn.
	(check_bitfield_type_and_width): Likewise.
	(declspecs_add_qual): Likewise.
	(declspecs_add_type): Likewise.
	(warn_variable_length_array): Unify function for -pedantic and -Wvla.
	Adjust to only call pedwarn_c90.
	(grokdeclarator): Remove pedantic && !flag_isoc99 check.  Call
	pedwarn_c90 instead of pedwarn.
	* c-errors.c (pedwarn_c90): Handle -Wc90-c99-compat.
	* c-parser.c (disable_extension_diagnostics): Handle
	warn_c90_c99_compat.
	(restore_extension_diagnostics): Likewise.
	(c_parser_enum_specifier): Remove check for !flag_isoc99.  Call
	pedwarn_c90 instead of pedwarn.
	(c_parser_initelt): Likewise.
	(c_parser_postfix_expression): Likewise.
	(c_parser_postfix_expression_after_paren_type): Likewise.
	(c_parser_compound_statement_nostart): Remove check for !flag_isoc99.
	* c-tree.h: Fix formatting.
	* c-typeck.c (build_array_ref): Remove check for !flag_isoc99.  Call
	pedwarn_c90 instead of pedwarn.
gcc/testsuite/
	* gcc.dg/Wc90-c99-compat-1.c: New test.
	* gcc.dg/Wc90-c99-compat-2.c: New test.
	* gcc.dg/Wc90-c99-compat-3.c: New test.
	* gcc.dg/Wc90-c99-compat-4.c: New test.
	* gcc.dg/Wc90-c99-compat-5.c: New test.
	* gcc.dg/Wc90-c99-compat-6.c: New test.
	* gcc.dg/wvla-1.c: Adjust dg-warning.
	* gcc.dg/wvla-2.c: Adjust dg-warning.
	* gcc.dg/wvla-4.c: Adjust dg-warning.
	* gcc.dg/wvla-6.c: Adjust dg-warning.
libcpp/
	* lex.c (_cpp_lex_direct): Warn when -Wc90-c99-compat is in effect.
	* charset.c (_cpp_valid_ucn): Likewise.
	* include/cpplib.h (cpp_options): Add cpp_warn_c90_c99_compat.
	* macro.c (replace_args): Warn when -Wc90-c99-compat is in effect.
	(parse_params): Likewise.

From-SVN: r213786

6 files changed, 117 insertions, 104 deletions

diff --git a/gcc/c/ChangeLog b/gcc/c/ChangeLog
index 3dcd81f..154768b 100644
--- a/gcc/c/ChangeLog
+++ b/gcc/c/ChangeLog
@@ -1,3 +1,29 @@
+2014-08-10 Marek Polacek  <polacek@redhat.com>
+
+	PR c/51849
+	* c-decl.c (build_array_declarator): Remove check for !flag_isoc99.
+	Call pedwarn_c90 instead of pedwarn.
+	(check_bitfield_type_and_width): Likewise.
+	(declspecs_add_qual): Likewise.
+	(declspecs_add_type): Likewise.
+	(warn_variable_length_array): Unify function for -pedantic and -Wvla.
+	Adjust to only call pedwarn_c90.
+	(grokdeclarator): Remove pedantic && !flag_isoc99 check.  Call
+	pedwarn_c90 instead of pedwarn.
+	* c-errors.c (pedwarn_c90): Handle -Wc90-c99-compat.
+	* c-parser.c (disable_extension_diagnostics): Handle
+	warn_c90_c99_compat.
+	(restore_extension_diagnostics): Likewise.
+	(c_parser_enum_specifier): Remove check for !flag_isoc99.  Call
+	pedwarn_c90 instead of pedwarn.
+	(c_parser_initelt): Likewise.
+	(c_parser_postfix_expression): Likewise.
+	(c_parser_postfix_expression_after_paren_type): Likewise.
+	(c_parser_compound_statement_nostart): Remove check for !flag_isoc99.
+	* c-tree.h: Fix formatting.
+	* c-typeck.c (build_array_ref): Remove check for !flag_isoc99.  Call
+	pedwarn_c90 instead of pedwarn.
+
 2014-08-07  Trevor Saunders  <tsaunders@mozilla.com>
 
 	* c-typeck.c: Remove include of pointer-set.h.
diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c
index 050ddff..7ba35bf 100644
--- a/gcc/c/c-decl.c
+++ b/gcc/c/c-decl.c
@@ -3968,16 +3968,13 @@ build_array_declarator (location_t loc,
     }
   declarator->u.array.static_p = static_p;
   declarator->u.array.vla_unspec_p = vla_unspec_p;
-  if (!flag_isoc99)
-    {
-      if (static_p || quals != NULL)
-	pedwarn (loc, OPT_Wpedantic,
+  if (static_p || quals != NULL)
+    pedwarn_c90 (loc, OPT_Wpedantic,
 		 "ISO C90 does not support %<static%> or type "
 		 "qualifiers in parameter array declarators");
-      if (vla_unspec_p)
-	pedwarn (loc, OPT_Wpedantic,
+  if (vla_unspec_p)
+    pedwarn_c90 (loc, OPT_Wpedantic,
 		 "ISO C90 does not support %<[*]%> array declarators");
-    }
   if (vla_unspec_p)
     {
       if (!current_scope->parm_flag)
@@ -4891,10 +4888,9 @@ check_bitfield_type_and_width (tree *type, tree *width, tree orig_name)
   if (!in_system_header_at (input_location)
       && type_mv != integer_type_node
       && type_mv != unsigned_type_node
-      && type_mv != boolean_type_node
-      && !flag_isoc99)
-    pedwarn (input_location, OPT_Wpedantic,
-	     "type of bit-field %qs is a GCC extension", name);
+      && type_mv != boolean_type_node)
+    pedwarn_c90 (input_location, OPT_Wpedantic,
+		 "type of bit-field %qs is a GCC extension", name);
 
   max_width = TYPE_PRECISION (*type);
 
@@ -4925,52 +4921,27 @@ static void
 warn_variable_length_array (tree name, tree size)
 {
   int const_size = TREE_CONSTANT (size);
+  enum opt_code opt = (warn_vla == -1 && !warn_c90_c99_compat)
+		      ? OPT_Wpedantic : OPT_Wvla;
 
-  if (!flag_isoc99 && pedantic && warn_vla != 0)
+  if (const_size)
     {
-      if (const_size)
-	{
-	  if (name)
-	    pedwarn (input_location, OPT_Wvla,
+      if (name)
+	pedwarn_c90 (input_location, opt,
 		     "ISO C90 forbids array %qE whose size "
-		     "can%'t be evaluated",
-		     name);
-	  else
-	    pedwarn (input_location, OPT_Wvla, "ISO C90 forbids array whose size "
-		     "can%'t be evaluated");
-	}
+		     "can%'t be evaluated", name);
       else
-	{
-	  if (name)
-	    pedwarn (input_location, OPT_Wvla,
-		     "ISO C90 forbids variable length array %qE",
-		     name);
-	  else
-	    pedwarn (input_location, OPT_Wvla, "ISO C90 forbids variable length array");
-	}
+	pedwarn_c90 (input_location, opt, "ISO C90 forbids array "
+		     "whose size can%'t be evaluated");
     }
-  else if (warn_vla > 0)
+  else
     {
-      if (const_size)
-        {
-	  if (name)
-	    warning (OPT_Wvla,
-		     "the size of array %qE can"
-		     "%'t be evaluated", name);
-	  else
-	    warning (OPT_Wvla,
-		     "the size of array can %'t be evaluated");
-	}
+      if (name)
+	pedwarn_c90 (input_location, opt,
+		     "ISO C90 forbids variable length array %qE", name);
       else
-	{
-	  if (name)
-	    warning (OPT_Wvla,
-		     "variable length array %qE is used",
-		     name);
-	  else
-	    warning (OPT_Wvla,
-		     "variable length array is used");
-	}
+	pedwarn_c90 (input_location, opt, "ISO C90 forbids variable "
+		     "length array");
     }
 }
 
@@ -5186,18 +5157,14 @@ grokdeclarator (const struct c_declarator *declarator,
   as2 = TYPE_ADDR_SPACE (element_type);
   address_space = ADDR_SPACE_GENERIC_P (as1)? as2 : as1;
 
-  if (pedantic && !flag_isoc99)
-    {
-      if (constp > 1)
-	pedwarn (loc, OPT_Wpedantic, "duplicate %<const%>");
-      if (restrictp > 1)
-	pedwarn (loc, OPT_Wpedantic, "duplicate %<restrict%>");
-      if (volatilep > 1)
-	pedwarn (loc, OPT_Wpedantic, "duplicate %<volatile%>");
-      if (atomicp > 1)
-	pedwarn (loc, OPT_Wpedantic, "duplicate %<_Atomic%>");
-
-    }
+  if (constp > 1)
+    pedwarn_c90 (loc, OPT_Wpedantic, "duplicate %<const%>");
+  if (restrictp > 1)
+    pedwarn_c90 (loc, OPT_Wpedantic, "duplicate %<restrict%>");
+  if (volatilep > 1)
+    pedwarn_c90 (loc, OPT_Wpedantic, "duplicate %<volatile%>");
+  if (atomicp > 1)
+    pedwarn_c90 (loc, OPT_Wpedantic, "duplicate %<_Atomic%>");
 
   if (!ADDR_SPACE_GENERIC_P (as1) && !ADDR_SPACE_GENERIC_P (as2) && as1 != as2)
     error_at (loc, "conflicting named address spaces (%s vs %s)",
@@ -5602,10 +5569,9 @@ grokdeclarator (const struct c_declarator *declarator,
 		    flexible_array_member = (t->kind == cdk_id);
 		  }
 		if (flexible_array_member
-		    && pedantic && !flag_isoc99
 		    && !in_system_header_at (input_location))
-		  pedwarn (loc, OPT_Wpedantic,
-			   "ISO C90 does not support flexible array members");
+		  pedwarn_c90 (loc, OPT_Wpedantic, "ISO C90 does not "
+			       "support flexible array members");
 
 		/* ISO C99 Flexible array members are effectively
 		   identical to GCC's zero-length array extension.  */
@@ -9136,8 +9102,8 @@ declspecs_add_qual (source_location loc,
     default:
       gcc_unreachable ();
     }
-  if (dupe && !flag_isoc99)
-    pedwarn (loc, OPT_Wpedantic, "duplicate %qE", qual);
+  if (dupe)
+    pedwarn_c90 (loc, OPT_Wpedantic, "duplicate %qE", qual);
   return specs;
 }
 
@@ -9381,9 +9347,9 @@ declspecs_add_type (location_t loc, struct c_declspecs *specs,
 	      break;
 	    case RID_COMPLEX:
 	      dupe = specs->complex_p;
-	      if (!flag_isoc99 && !in_system_header_at (loc))
-		pedwarn (loc, OPT_Wpedantic,
-			 "ISO C90 does not support complex types");
+	      if (!in_system_header_at (loc))
+		pedwarn_c90 (loc, OPT_Wpedantic,
+			     "ISO C90 does not support complex types");
 	      if (specs->typespec_word == cts_auto_type)
 		error_at (loc,
 			  ("both %<complex%> and %<__auto_type%> in "
@@ -9599,9 +9565,9 @@ declspecs_add_type (location_t loc, struct c_declspecs *specs,
 		}
 	      return specs;
 	    case RID_BOOL:
-	      if (!flag_isoc99 && !in_system_header_at (loc))
-		pedwarn (loc, OPT_Wpedantic,
-			 "ISO C90 does not support boolean types");
+	      if (!in_system_header_at (loc))
+		pedwarn_c90 (loc, OPT_Wpedantic,
+			     "ISO C90 does not support boolean types");
 	      if (specs->long_p)
 		error_at (loc,
 			  ("both %<long%> and %<_Bool%> in "
diff --git a/gcc/c/c-errors.c b/gcc/c/c-errors.c
index 92136e7..5a95b88 100644
--- a/gcc/c/c-errors.c
+++ b/gcc/c/c-errors.c
@@ -44,21 +44,38 @@ pedwarn_c99 (location_t location, int opt, const char *gmsgid, ...)
   va_end (ap);
 }
 
-/* Issue an ISO C90 pedantic warning MSGID.  This function is supposed to
-   be used for matters that are allowed in ISO C99 but not supported in
-   ISO C90, thus we explicitly don't pedwarn when C99 is specified.
-   (There is no flag_c90.)  */
+/* Issue an ISO C90 pedantic warning MSGID if -pedantic outside C99 mode,
+   otherwise issue warning MSGID if -Wc90-c99-compat is specified, or if
+   a specific option such as -Wlong-long is specified.
+   This function is supposed to be used for matters that are allowed in
+   ISO C99 but not supported in ISO C90, thus we explicitly don't pedwarn
+   when C99 is specified.  (There is no flag_c90.)  */
 
 void
 pedwarn_c90 (location_t location, int opt, const char *gmsgid, ...)
 {
   diagnostic_info diagnostic;
   va_list ap;
+  bool warned = false;
 
   va_start (ap, gmsgid);
-  diagnostic_set_info (&diagnostic, gmsgid, &ap, location,
-		       flag_isoc99 ? DK_WARNING : DK_PEDWARN);
-  diagnostic.option_index = opt;
-  report_diagnostic (&diagnostic);
+  if (pedantic && !flag_isoc99)
+    {
+      diagnostic_set_info (&diagnostic, gmsgid, &ap, location, DK_PEDWARN);
+      diagnostic.option_index = opt;
+      warned = report_diagnostic (&diagnostic);
+    }
+  else if (opt != OPT_Wpedantic)
+    {
+      diagnostic_set_info (&diagnostic, gmsgid, &ap, location, DK_WARNING);
+      diagnostic.option_index = opt;
+      warned = report_diagnostic (&diagnostic);
+    }
+  if (warn_c90_c99_compat && !warned)
+    {
+      diagnostic_set_info (&diagnostic, gmsgid, &ap, location, DK_WARNING);
+      diagnostic.option_index = OPT_Wc90_c99_compat;
+      report_diagnostic (&diagnostic);
+    }
   va_end (ap);
 }
diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c
index e32bf04..ca8577c 100644
--- a/gcc/c/c-parser.c
+++ b/gcc/c/c-parser.c
@@ -1072,7 +1072,8 @@ disable_extension_diagnostics (void)
 	     | (flag_iso << 3)
 	     | (warn_long_long << 4)
 	     | (warn_cxx_compat << 5)
-	     | (warn_overlength_strings << 6));
+	     | (warn_overlength_strings << 6)
+	     | (warn_c90_c99_compat << 7));
   cpp_opts->cpp_pedantic = pedantic = 0;
   warn_pointer_arith = 0;
   cpp_opts->cpp_warn_traditional = warn_traditional = 0;
@@ -1080,6 +1081,7 @@ disable_extension_diagnostics (void)
   cpp_opts->cpp_warn_long_long = warn_long_long = 0;
   warn_cxx_compat = 0;
   warn_overlength_strings = 0;
+  warn_c90_c99_compat = 0;
   return ret;
 }
 
@@ -1096,6 +1098,7 @@ restore_extension_diagnostics (int flags)
   cpp_opts->cpp_warn_long_long = warn_long_long = (flags >> 4) & 1;
   warn_cxx_compat = (flags >> 5) & 1;
   warn_overlength_strings = (flags >> 6) & 1;
+  warn_c90_c99_compat = (flags >> 7) & 1;
 }
 
 /* Possibly kinds of declarator to parse.  */
@@ -2545,8 +2548,9 @@ c_parser_enum_specifier (c_parser *parser)
 	    }
 	  if (c_parser_next_token_is (parser, CPP_CLOSE_BRACE))
 	    {
-	      if (seen_comma && !flag_isoc99)
-		pedwarn (comma_loc, OPT_Wpedantic, "comma at end of enumerator list");
+	      if (seen_comma)
+		pedwarn_c90 (comma_loc, OPT_Wpedantic,
+			     "comma at end of enumerator list");
 	      c_parser_consume_token (parser);
 	      break;
 	    }
@@ -4348,9 +4352,9 @@ c_parser_initelt (c_parser *parser, struct obstack * braced_init_obstack)
 	{
 	  if (c_parser_next_token_is (parser, CPP_EQ))
 	    {
-	      if (!flag_isoc99)
-		pedwarn (des_loc, OPT_Wpedantic,
-			 "ISO C90 forbids specifying subobject to initialize");
+	      pedwarn_c90 (des_loc, OPT_Wpedantic,
+			   "ISO C90 forbids specifying subobject "
+			   "to initialize");
 	      c_parser_consume_token (parser);
 	    }
 	  else
@@ -4566,10 +4570,9 @@ c_parser_compound_statement_nostart (c_parser *parser)
 	  c_parser_declaration_or_fndef (parser, true, true, true, true,
 					 true, NULL, vNULL);
 	  if (last_stmt)
-	    pedwarn_c90 (loc,
-			 (pedantic && !flag_isoc99)
-			 ? OPT_Wpedantic
-			 : OPT_Wdeclaration_after_statement,
+	    pedwarn_c90 (loc, (pedantic && !flag_isoc99)
+			       ? OPT_Wpedantic
+			       : OPT_Wdeclaration_after_statement,
 			 "ISO C90 forbids mixed declarations and code");
 	  last_stmt = false;
 	}
@@ -4598,8 +4601,8 @@ c_parser_compound_statement_nostart (c_parser *parser)
 	      restore_extension_diagnostics (ext);
 	      if (last_stmt)
 		pedwarn_c90 (loc, (pedantic && !flag_isoc99)
-			     ? OPT_Wpedantic
-			     : OPT_Wdeclaration_after_statement,
+				  ? OPT_Wpedantic
+				  : OPT_Wdeclaration_after_statement,
 			     "ISO C90 forbids mixed declarations and code");
 	      last_stmt = false;
 	    }
@@ -7401,9 +7404,8 @@ c_parser_postfix_expression (c_parser *parser)
 		expr.value = error_mark_node;
 		break;
 	      }
-	    if (!flag_isoc99)
-	      pedwarn (loc, OPT_Wpedantic,
-		       "ISO C90 does not support complex types");
+	    pedwarn_c90 (loc, OPT_Wpedantic,
+			 "ISO C90 does not support complex types");
 	    expr.value = build2 (COMPLEX_EXPR,
 				 build_complex_type
 				   (TYPE_MAIN_VARIANT
@@ -7607,8 +7609,7 @@ c_parser_postfix_expression_after_paren_type (c_parser *parser,
       type = error_mark_node;
     }
 
-  if (!flag_isoc99)
-    pedwarn (start_loc, OPT_Wpedantic, "ISO C90 forbids compound literals");
+  pedwarn_c90 (start_loc, OPT_Wpedantic, "ISO C90 forbids compound literals");
   non_const = ((init.value && TREE_CODE (init.value) == CONSTRUCTOR)
 	       ? CONSTRUCTOR_NON_CONST (init.value)
 	       : init.original_code == C_MAYBE_CONST_EXPR);
diff --git a/gcc/c/c-tree.h b/gcc/c/c-tree.h
index f97d0d5..55e71dc 100644
--- a/gcc/c/c-tree.h
+++ b/gcc/c/c-tree.h
@@ -676,7 +676,9 @@ extern tree c_omp_reduction_lookup (tree, tree);
 extern tree c_check_omp_declare_reduction_r (tree *, int *, void *);
 
 /* In c-errors.c */
-extern void pedwarn_c90 (location_t, int opt, const char *, ...) ATTRIBUTE_GCC_DIAG(3,4);
-extern void pedwarn_c99 (location_t, int opt, const char *, ...) ATTRIBUTE_GCC_DIAG(3,4);
+extern void pedwarn_c90 (location_t, int opt, const char *, ...)
+    ATTRIBUTE_GCC_DIAG(3,4);
+extern void pedwarn_c99 (location_t, int opt, const char *, ...)
+    ATTRIBUTE_GCC_DIAG(3,4);
 
 #endif /* ! GCC_C_TREE_H */
diff --git a/gcc/c/c-typeck.c b/gcc/c/c-typeck.c
index f8a2316..0ed92c6 100644
--- a/gcc/c/c-typeck.c
+++ b/gcc/c/c-typeck.c
@@ -2510,7 +2510,7 @@ build_array_ref (location_t loc, tree array, tree index)
 	    return error_mark_node;
 	}
 
-      if (pedantic)
+      if (pedantic || warn_c90_c99_compat)
 	{
 	  tree foo = array;
 	  while (TREE_CODE (foo) == COMPONENT_REF)
@@ -2518,9 +2518,10 @@ build_array_ref (location_t loc, tree array, tree index)
 	  if (TREE_CODE (foo) == VAR_DECL && C_DECL_REGISTER (foo))
 	    pedwarn (loc, OPT_Wpedantic,
 		     "ISO C forbids subscripting %<register%> array");
-	  else if (!flag_isoc99 && !lvalue_p (foo))
-	    pedwarn (loc, OPT_Wpedantic,
-		     "ISO C90 forbids subscripting non-lvalue array");
+	  else if (!lvalue_p (foo))
+	    pedwarn_c90 (loc, OPT_Wpedantic,
+			 "ISO C90 forbids subscripting non-lvalue "
+			 "array");
 	}
 
       type = TREE_TYPE (TREE_TYPE (array));