2007-02-15 Manuel Lopez-Ibanez <manu@gcc.gnu.org>

	PR c/26494
	* doc/invoke.texi (Warning Options): Remove
	-Werror-implicit-function-declaration.
	(Wimplicit-function-declaration): Update description.
	* opts.c (common_handle_option): Move handling of -Werror=* to...
	(enable_warning_as_error): ...here.
	* opts.h (enable_warning_as_error): Declare.
	* c-decl.c (implicit_decl_warning): Unless
	-Wno-implicit-function-declaration is given, emit a pedwarn if
	-std=c99 or emit a warning if -Wimplicit-function-declaration.
	* c.opt (Wimplicit-function-declaration): Replace
	mesg_implicit_function_declaration with
	warn_implicit_function_declaration.
	* c-opts.c (c_common_handle_option):
	-Werror-implicit-function-declaration is exactly equal as
	-Werror=implicit-function-declaration.
	(set_Wimplicit): Replace mesg_implicit_function_declaration with
	warn_implicit_function_declaration.
	(c_common_post_options): -Wimplict-function-declaration is enabled
	by default by -std=c99, otherwise is disabled by default.
	* c-objc-common.c (c_objc_common_init): Remove flawed logic.
testsuite/
	* gcc.dg/Wimplicit-function-declaration-c89.c: New.
	* gcc.dg/Wimplicit-function-declaration-c89-default.c: New.
	* gcc.dg/Wimplicit-function-declaration-c89-pedantic.c: New.
	* gcc.dg/Wimplicit-function-declaration-c99.c: New.
	* gcc.dg/Wimplicit-function-declaration-c99-pedantic.c: New.
	* gcc.dg/Werror-implicit-function-declaration.c: New.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@122017 138bc75d-0d04-0410-961f-82ee72b054a4

15 files changed, 136 insertions, 63 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 2ea38dd90ea..70efcfe0116 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,27 @@
+2007-02-15  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
+
+	PR c/26494
+	* doc/invoke.texi (Warning Options): Remove
+	-Werror-implicit-function-declaration.
+	(Wimplicit-function-declaration): Update description.
+	* opts.c (common_handle_option): Move handling of -Werror=* to...
+	(enable_warning_as_error): ...here.
+	* opts.h (enable_warning_as_error): Declare.
+	* c-decl.c (implicit_decl_warning): Unless
+	-Wno-implicit-function-declaration is given, emit a pedwarn if
+	-std=c99 or emit a warning if -Wimplicit-function-declaration.
+	* c.opt (Wimplicit-function-declaration): Replace
+	mesg_implicit_function_declaration with
+	warn_implicit_function_declaration.
+	* c-opts.c (c_common_handle_option):
+	-Werror-implicit-function-declaration is exactly equal as
+	-Werror=implicit-function-declaration.
+	(set_Wimplicit): Replace mesg_implicit_function_declaration with
+	warn_implicit_function_declaration.
+	(c_common_post_options): -Wimplict-function-declaration is enabled
+	by default by -std=c99, otherwise is disabled by default.
+	* c-objc-common.c (c_objc_common_init): Remove flawed logic.
+
 2007-02-15  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* gimplify.c (gimplify_modify_expr): During gimplification, attach a
diff --git a/gcc/c-decl.c b/gcc/c-decl.c
index 648c805828d..ed0bf9cb25d 100644
--- a/gcc/c-decl.c
+++ b/gcc/c-decl.c
@@ -2376,18 +2376,16 @@ pushdecl_top_level (tree x)
 static void
 implicit_decl_warning (tree id, tree olddecl)
 {
-  void (*diag) (const char *, ...) ATTRIBUTE_GCC_CDIAG(1,2);
-  switch (mesg_implicit_function_declaration)
+  if (warn_implicit_function_declaration)
     {
-    case 0: return;
-    case 1: diag = warning0; break;
-    case 2: diag = error;   break;
-    default: gcc_unreachable ();
+      if (flag_isoc99)
+	pedwarn (G_("implicit declaration of function %qE"), id);
+      else 
+	warning (OPT_Wimplicit_function_declaration, 
+		 G_("implicit declaration of function %qE"), id);
+      if (olddecl)
+	locate_old_decl (olddecl, inform);
     }
-
-  diag (G_("implicit declaration of function %qE"), id);
-  if (olddecl)
-    locate_old_decl (olddecl, diag);
 }
 
 /* Generate an implicit declaration for identifier FUNCTIONID as a
diff --git a/gcc/c-objc-common.c b/gcc/c-objc-common.c
index d4ad1f89f26..7604bc284db 100644
--- a/gcc/c-objc-common.c
+++ b/gcc/c-objc-common.c
@@ -135,16 +135,6 @@ c_objc_common_init (void)
      want an enhanced ObjC implementation.  */
   diagnostic_format_decoder (global_dc) = &c_tree_printer;
 
-  /* If still unspecified, make it match -std=c99
-     (allowing for -pedantic-errors).  */
-  if (mesg_implicit_function_declaration < 0)
-    {
-      if (flag_isoc99)
-	mesg_implicit_function_declaration = flag_pedantic_errors ? 2 : 1;
-      else
-	mesg_implicit_function_declaration = 0;
-    }
-
   return true;
 }
 
diff --git a/gcc/c-opts.c b/gcc/c-opts.c
index 9ac433a4f3a..76ad8271d72 100644
--- a/gcc/c-opts.c
+++ b/gcc/c-opts.c
@@ -451,8 +451,10 @@ c_common_handle_option (size_t scode, const char *arg, int value)
       global_dc->warning_as_error_requested = value;
       break;
 
-    case OPT_Werror_implicit_function_declaration:
-      mesg_implicit_function_declaration = 2;
+    case OPT_Werror_implicit_function_declaration: 
+      /* For backward compatibility, this is the same as
+	 -Werror=implicit-function-declaration.  */
+      enable_warning_as_error ("implicit-function-declaration", value, CL_C | CL_ObjC); 
       break;
 
     case OPT_Wformat:
@@ -1079,6 +1081,10 @@ c_common_post_options (const char **pfilename)
 	       "-Wformat-security ignored without -Wformat");
     }
 
+  /* -Wimplicit-function-declaration is enabled by default for C99.  */
+  if (warn_implicit_function_declaration == -1) 
+    warn_implicit_function_declaration = flag_isoc99;
+
   /* C99 requires special handling of complex multiplication and division;
      -ffast-math and -fcx-limited-range are handled in process_options.  */
   if (flag_isoc99)
@@ -1570,13 +1576,7 @@ set_Wimplicit (int on)
 {
   warn_implicit = on;
   warn_implicit_int = on;
-  if (on)
-    {
-      if (mesg_implicit_function_declaration != 2)
-	mesg_implicit_function_declaration = 1;
-    }
-  else
-    mesg_implicit_function_declaration = 0;
+  warn_implicit_function_declaration = on;
 }
 
 /* Args to -d specify what to dump.  Silently ignore
diff --git a/gcc/c.opt b/gcc/c.opt
index 624b10e9ede..512882bc64b 100644
--- a/gcc/c.opt
+++ b/gcc/c.opt
@@ -194,7 +194,7 @@ C ObjC C++ ObjC++
 
 Werror-implicit-function-declaration
 C ObjC RejectNegative Warning
-Make implicit function declarations an error
+This switch is deprecated; use -Werror=implicit-function-declaration instead
 
 Wfloat-equal
 C ObjC C++ ObjC++ Var(warn_float_equal) Warning
@@ -235,7 +235,7 @@ Wimplicit
 C ObjC C++ ObjC++ Warning
 
 Wimplicit-function-declaration
-C ObjC Var(mesg_implicit_function_declaration) Init(-1) Warning
+C ObjC Var(warn_implicit_function_declaration) Init(-1) Warning
 Warn about implicit function declarations
 
 Wimplicit-int
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 8e811936fef..3bc4d900184 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -229,7 +229,7 @@ Objective-C and Objective-C++ Dialects}.
 -Wconversion -Wcoverage-mismatch -Wno-deprecated-declarations @gol
 -Wdisabled-optimization  -Wno-div-by-zero  @gol
 -Wempty-body  -Wno-endif-labels @gol
--Werror  -Werror-* -Werror-implicit-function-declaration @gol
+-Werror  -Werror=* @gol
 -Wfatal-errors  -Wfloat-equal  -Wformat  -Wformat=2 @gol
 -Wno-format-extra-args -Wformat-nonliteral @gol
 -Wformat-security  -Wformat-y2k @gol
@@ -2626,13 +2626,13 @@ Warn when a declaration does not specify a type.
 This warning is enabled by @option{-Wall}.
 
 @item -Wimplicit-function-declaration
-@itemx -Werror-implicit-function-declaration
 @opindex Wimplicit-function-declaration
-@opindex Werror-implicit-function-declaration
-Give a warning (or error) whenever a function is used before being
-declared.  The form @option{-Wno-error-implicit-function-declaration}
-is not supported.
-This warning is enabled by @option{-Wall} (as a warning, not an error).
+@opindex Wno-implicit-function-declaration
+Give a warning whenever a function is used before being declared. In
+C99 mode (@option{-std=c99} or @option{-std=gnu99}), this warning is
+enabled by default and it is made into an error by
+@option{-pedantic-errors}. This warning is also enabled by
+@option{-Wall}.
 
 @item -Wimplicit
 @opindex Wimplicit
diff --git a/gcc/opts.c b/gcc/opts.c
index 1361eb77922..c84bc2a3c35 100644
--- a/gcc/opts.c
+++ b/gcc/opts.c
@@ -1067,31 +1067,7 @@ common_handle_option (size_t scode, const char *arg, int value,
       break;
 
     case OPT_Werror_:
-      {
-	char *new_option;
-	int option_index;
-
-	new_option = XNEWVEC (char, strlen (arg) + 2);
-	new_option[0] = 'W';
-	strcpy (new_option+1, arg);
-	option_index = find_opt (new_option, lang_mask);
-	if (option_index == N_OPTS)
-	  {
-	    error ("-Werror-%s: No option -%s", arg, new_option);
-	  }
-	else
-	  {
-	    int kind = value ? DK_ERROR : DK_WARNING;
-	    diagnostic_classify_diagnostic (global_dc, option_index, kind);
-
-	    /* -Werror=foo implies -Wfoo.  */
-	    if (cl_options[option_index].var_type == CLVC_BOOLEAN
-		&& cl_options[option_index].flag_var
-		&& kind == DK_ERROR)
-	      *(int *) cl_options[option_index].flag_var = 1;
-	    free (new_option);
-	  }
-      }
+      enable_warning_as_error (arg, value, lang_mask);
       break;
 
     case OPT_Wextra:
@@ -1607,3 +1583,34 @@ get_option_state (int option, struct cl_option_state *state)
     }
   return true;
 }
+
+/* Enable a warning option as an error.  This is used by -Werror= and
+   also by legacy Werror-implicit-function-declaration.  */
+
+void
+enable_warning_as_error (const char *arg, int value, unsigned int lang_mask)
+{
+  char *new_option;
+  int option_index;
+
+  new_option = XNEWVEC (char, strlen (arg) + 2);
+  new_option[0] = 'W';
+  strcpy (new_option + 1, arg);
+  option_index = find_opt (new_option, lang_mask);
+  if (option_index == N_OPTS)
+    {
+      error ("-Werror=%s: No option -%s", arg, new_option);
+    }
+  else
+    {
+      int kind = value ? DK_ERROR : DK_WARNING;
+      diagnostic_classify_diagnostic (global_dc, option_index, kind);
+      
+      /* -Werror=foo implies -Wfoo.  */
+      if (cl_options[option_index].var_type == CLVC_BOOLEAN
+	  && cl_options[option_index].flag_var
+	  && kind == DK_ERROR)
+	*(int *) cl_options[option_index].flag_var = 1;
+    }
+  free (new_option);
+}
diff --git a/gcc/opts.h b/gcc/opts.h
index b60cb47a16f..485cc22e20e 100644
--- a/gcc/opts.h
+++ b/gcc/opts.h
@@ -104,4 +104,6 @@ extern void decode_options (unsigned int argc, const char **argv);
 extern int option_enabled (int opt_idx);
 extern bool get_option_state (int, struct cl_option_state *);
 
+extern void enable_warning_as_error (const char *arg, int value,
+				     unsigned int lang_mask);
 #endif
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index b876518ecee..67076ea1c80 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,15 @@
 2007-02-15  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
 
+	PR c/26494
+	* gcc.dg/Wimplicit-function-declaration-c89.c: New.
+	* gcc.dg/Wimplicit-function-declaration-c89-default.c: New.
+	* gcc.dg/Wimplicit-function-declaration-c89-pedantic.c: New.
+	* gcc.dg/Wimplicit-function-declaration-c99.c: New.
+	* gcc.dg/Wimplicit-function-declaration-c99-pedantic.c: New.
+	* gcc.dg/Werror-implicit-function-declaration.c: New.
+
+2007-02-15  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
+
 	PR c++/28943
 	* g++.dg/warn/pr28943.C: New.
 
diff --git a/gcc/testsuite/gcc.dg/Werror-implicit-function-declaration.c b/gcc/testsuite/gcc.dg/Werror-implicit-function-declaration.c
new file mode 100644
index 00000000000..f8f0f81d408
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Werror-implicit-function-declaration.c
@@ -0,0 +1,7 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c89 -Werror-implicit-function-declaration" } */
+
+void f(void) 
+{ 
+  puts("Hello"); /* { dg-error "error: implicit declaration of function" } */
+}
diff --git a/gcc/testsuite/gcc.dg/Wimplicit-function-declaration-c89-default.c b/gcc/testsuite/gcc.dg/Wimplicit-function-declaration-c89-default.c
new file mode 100644
index 00000000000..c725ffaca46
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Wimplicit-function-declaration-c89-default.c
@@ -0,0 +1,7 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c89" } */
+
+void f(void) 
+{ 
+  puts("Hello"); /* { dg-bogus "warning: implicit declaration of function" } */
+}
diff --git a/gcc/testsuite/gcc.dg/Wimplicit-function-declaration-c89-pedantic.c b/gcc/testsuite/gcc.dg/Wimplicit-function-declaration-c89-pedantic.c
new file mode 100644
index 00000000000..f476e6af187
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Wimplicit-function-declaration-c89-pedantic.c
@@ -0,0 +1,7 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c89 -pedantic-errors -Wimplicit-function-declaration" } */
+
+void f(void) 
+{ 
+  puts("Hello"); /* { dg-warning "warning: implicit declaration of function" } */
+}
diff --git a/gcc/testsuite/gcc.dg/Wimplicit-function-declaration-c89.c b/gcc/testsuite/gcc.dg/Wimplicit-function-declaration-c89.c
new file mode 100644
index 00000000000..6f2916d0ab3
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Wimplicit-function-declaration-c89.c
@@ -0,0 +1,7 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c89 -Wimplicit-function-declaration" } */
+
+void f(void) 
+{ 
+  puts("Hello"); /* { dg-warning "warning: implicit declaration of function" } */
+}
diff --git a/gcc/testsuite/gcc.dg/Wimplicit-function-declaration-c99-pedantic.c b/gcc/testsuite/gcc.dg/Wimplicit-function-declaration-c99-pedantic.c
new file mode 100644
index 00000000000..6ea5eeda3f1
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Wimplicit-function-declaration-c99-pedantic.c
@@ -0,0 +1,7 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c99 -pedantic-errors -Wall" } */
+
+void f(void) 
+{ 
+  puts("Hello"); /* { dg-error "error: implicit declaration of function" } */
+}
diff --git a/gcc/testsuite/gcc.dg/Wimplicit-function-declaration-c99.c b/gcc/testsuite/gcc.dg/Wimplicit-function-declaration-c99.c
new file mode 100644
index 00000000000..004fc5ac5af
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Wimplicit-function-declaration-c99.c
@@ -0,0 +1,7 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c99" } */
+
+void f(void) 
+{ 
+  puts("Hello"); /* { dg-warning "warning: implicit declaration of function" } */
+}