* c-parse.in (lineno_stmt_decl_or_labels_ending_decl): Also warn

	when warn_declaration_after_statement.  Call pedwarn_c90, not
	pedwarn.  Correct message: it's "ISO C90", not "ISO C89".
	* c-common.c (warn_declaration_after_statement): Define.
	* c-common.h (warn_declaration_after_statement): Declare.
	* c.opt (Wdeclaration-after-statement): New.
	* c-errors.c (pedwarn_c90): New function.
	* c-opts.c (c_common_handle_option) <case
	OPT_Wdeclaration_after_statement>: New.
	* c-tree.h (pedwarn_c90): Declare.
	* doc/invoke.texi (Option Summary): Document
	-Wdeclaration-after-statement.
	(Warning Options): Ditto.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@69899 138bc75d-0d04-0410-961f-82ee72b054a4

9 files changed, 66 insertions, 3 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 372f834b9f5..b7ac766e232 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,20 @@
+2003-07-28  Hans-Peter Nilsson  <hp@bitrange.com>
+	    Michael Culbertson  <Michael.J.Culbertson@wheaton.edu>
+
+	* c-parse.in (lineno_stmt_decl_or_labels_ending_decl): Also warn
+	when warn_declaration_after_statement.  Call pedwarn_c90, not
+	pedwarn.  Correct message: it's "ISO C90", not "ISO C89".
+	* c-common.c (warn_declaration_after_statement): Define.
+	* c-common.h (warn_declaration_after_statement): Declare.
+	* c.opt (Wdeclaration-after-statement): New.
+	* c-errors.c (pedwarn_c90): New function.
+	* c-opts.c (c_common_handle_option) <case
+	OPT_Wdeclaration_after_statement>: New.
+	* c-tree.h (pedwarn_c90): Declare.
+	* doc/invoke.texi (Option Summary): Document
+	-Wdeclaration-after-statement.
+	(Warning Options): Ditto.
+
 Mon Jul 28 20:13:06 CEST 2003  Jan Hubicka  <jh@suse.cz>
 
 	* i386.md (memory attribute) Avoid accessing uninitialized memory
diff --git a/gcc/c-common.c b/gcc/c-common.c
index 2e985c2a4d2..c579b16f37c 100644
--- a/gcc/c-common.c
+++ b/gcc/c-common.c
@@ -391,6 +391,10 @@ int warn_bad_function_cast;
 
 int warn_traditional;
 
+/* Nonzero means warn for a declaration found after a statement.  */
+
+int warn_declaration_after_statement;
+
 /* Nonzero means warn for non-prototype function decls
    or non-prototyped defs without previous prototype.  */
 
diff --git a/gcc/c-common.h b/gcc/c-common.h
index f46058f8b4e..5d4c3d42d5a 100644
--- a/gcc/c-common.h
+++ b/gcc/c-common.h
@@ -569,6 +569,10 @@ extern int warn_bad_function_cast;
 
 extern int warn_traditional;
 
+/* Nonzero means warn for a declaration found after a statement.  */
+
+extern int warn_declaration_after_statement;
+
 /* Nonzero means warn for non-prototype function decls
    or non-prototyped defs without previous prototype.  */
 
diff --git a/gcc/c-errors.c b/gcc/c-errors.c
index 2a2fdc0c440..fa71b8cfa97 100644
--- a/gcc/c-errors.c
+++ b/gcc/c-errors.c
@@ -43,3 +43,21 @@ pedwarn_c99 (const char *msgid, ...)
   report_diagnostic (&diagnostic);
   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.)  */
+
+void
+pedwarn_c90 (const char *msgid, ...)
+{
+  diagnostic_info diagnostic;
+  va_list ap;
+
+  va_start (ap, msgid);
+  diagnostic_set_info (&diagnostic, msgid, &ap, input_location,
+                       flag_isoc99 ? DK_WARNING : pedantic_error_kind ());
+  report_diagnostic (&diagnostic);
+  va_end (ap);
+}
diff --git a/gcc/c-opts.c b/gcc/c-opts.c
index a6dd9f0a5c8..5061a58e9f1 100644
--- a/gcc/c-opts.c
+++ b/gcc/c-opts.c
@@ -412,6 +412,10 @@ c_common_handle_option (size_t scode, const char *arg, int value)
       warn_ctor_dtor_privacy = value;
       break;
 
+    case OPT_Wdeclaration_after_statement:
+      warn_declaration_after_statement = value;
+      break;
+
     case OPT_Wdeprecated:
       warn_deprecated = value;
       cpp_opts->warn_deprecated = value;
diff --git a/gcc/c-parse.in b/gcc/c-parse.in
index 8ac14120e6f..22b1531afa1 100644
--- a/gcc/c-parse.in
+++ b/gcc/c-parse.in
@@ -2013,8 +2013,11 @@ lineno_stmt_decl_or_labels_ending_stmt:
 lineno_stmt_decl_or_labels_ending_decl:
 	  lineno_decl
 	| lineno_stmt_decl_or_labels_ending_stmt lineno_decl
-		{ if (pedantic && !flag_isoc99)
-		    pedwarn ("ISO C89 forbids mixed declarations and code"); }
+		{
+		  if ((pedantic && !flag_isoc99)
+		      || warn_declaration_after_statement)
+		    pedwarn_c90 ("ISO C90 forbids mixed declarations and code");
+		}
 	| lineno_stmt_decl_or_labels_ending_decl lineno_decl
 	| lineno_stmt_decl_or_labels_ending_error lineno_decl
 	;
diff --git a/gcc/c-tree.h b/gcc/c-tree.h
index 0a36609093a..cbc83a523a0 100644
--- a/gcc/c-tree.h
+++ b/gcc/c-tree.h
@@ -288,6 +288,7 @@ extern void set_init_index (tree, tree);
 extern void set_init_label (tree);
 extern void process_init_element (tree);
 extern tree build_compound_literal (tree, tree);
+extern void pedwarn_c90 (const char *, ...) ATTRIBUTE_PRINTF_1;
 extern void pedwarn_c99 (const char *, ...) ATTRIBUTE_PRINTF_1;
 extern tree c_start_case (tree);
 extern void c_finish_case (void);
diff --git a/gcc/c.opt b/gcc/c.opt
index 042f4cfc86d..15b96ad5e82 100644
--- a/gcc/c.opt
+++ b/gcc/c.opt
@@ -180,6 +180,10 @@ Wctor-dtor-privacy
 C++ ObjC++
 Warn when all constructors and destructors are private
 
+Wdeclaration-after-statement
+C ObjC
+Warn when a declaration is found after a statement
+
 Wdeprecated
 C++ ObjC++
 Warn about deprecated compiler features
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 5393d108134..edd657d7599 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -233,7 +233,8 @@ in the following sections.
 @item C-only Warning Options
 @gccoptlist{-Wbad-function-cast  -Wmissing-declarations @gol
 -Wmissing-prototypes  -Wnested-externs @gol
--Wstrict-prototypes  -Wtraditional}
+-Wstrict-prototypes  -Wtraditional @gol
+-Wdeclaration-after-statement}
 
 @item Debugging Options
 @xref{Debugging Options,,Options for Debugging Your Program or GCC}.
@@ -2609,6 +2610,13 @@ because that feature is already a gcc extension and thus not relevant to
 traditional C compatibility.
 @end itemize
 
+@item -Wdeclaration-after-statement @r{(C only)}
+@opindex Wdeclaration-after-statement
+Warn when a declaration is found after a statement in a block.  This
+construct, known from C++, was introduced with ISO C99 and is by default
+allowed in GCC@.  It is not supported by ISO C90 and was not supported by
+GCC versions before GCC 3.0.  @xref{Mixed Declarations}.
+
 @item -Wundef
 @opindex Wundef
 Warn if an undefined identifier is evaluated in an @samp{#if} directive.