re PR c/30551 (-pedantic does not include -Wmain, but -pedantic-errors does make -Wmain cause error messages)

2008-08-13  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>

	PR 30551
	* doc/invoke.texi (Wmain): Update.
	* c-decl.c (start_decl): warn_main is only 0 or 1.
	(start_function): Likewise. Fix formatting.
	(finish_function): Delete redundant warning.
	* c.opt (Wmain): Add Var(warn_main) and Init(-1).
	* c-opts (c_common_handle_option): -Wall only has effect if
	warn_main is uninitialized. OPT_Wmain is automatically
	handled. -pedantic also enables Wmain.
	(c_common_post_options): Handle all logic for Wmain here.
	* c-common.c (warn_main): Delete.
	(check_main_parameter_types): Make pedwarns conditional on
	OPT_Wmain.
	* c-common.h (warn_main): Delete.
cp/	
	* decl.c (grokfndecl): Call check_main_parameters_type only if
	-Wmain.
testsuite/
	* gcc.dg/pr30551.c: New.
	* gcc.dg/pr30551-2.c: New.
	* gcc.dg/pr30551-3.c: New.
	* gcc.dg/pr30551-4.c: New.
	* gcc.dg/pr30551-5.c: New.
	* gcc.dg/pr30551-6.c: New.
	* gcc.dg/tree-ssa/reassoc-3.c: Don't compile with -pedantic-errors.
	* g++.dg/warn/pr30551.C: New.
	* g++.dg/warn/pr30551-2.C: New.

From-SVN: r139063

19 files changed, 140 insertions, 62 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d74b64a..767f3b3 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,20 @@
+2008-08-13  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
+
+	PR 30551
+	* doc/invoke.texi (Wmain): Update.
+	* c-decl.c (start_decl): warn_main is only 0 or 1.
+	(start_function): Likewise. Fix formatting.
+	(finish_function): Delete redundant warning.
+	* c.opt (Wmain): Add Var(warn_main) and Init(-1).
+	* c-opts (c_common_handle_option): -Wall only has effect if
+	warn_main is uninitialized. OPT_Wmain is automatically
+	handled. -pedantic also enables Wmain.
+	(c_common_post_options): Handle all logic for Wmain here.
+	* c-common.c (warn_main): Delete.
+	(check_main_parameter_types): Make pedwarns conditional on
+	OPT_Wmain.
+	* c-common.h (warn_main): Delete.
+
 2008-08-13  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR middle-end/36701
diff --git a/gcc/c-common.c b/gcc/c-common.c
index 9302182..8bac9cb 100644
--- a/gcc/c-common.c
+++ b/gcc/c-common.c
@@ -342,10 +342,6 @@ int flag_isoc99;
 
 int flag_hosted = 1;
 
-/* Warn if main is suspicious.  */
-
-int warn_main;
-
 
 /* ObjC language option variables.  */
 
@@ -1363,7 +1359,8 @@ check_main_parameter_types (tree decl)
        {
        case 1:
          if (TYPE_MAIN_VARIANT (type) != integer_type_node)
-           pedwarn (0, "first argument of %q+D should be %<int%>", decl);
+           pedwarn (OPT_Wmain, "first argument of %q+D should be %<int%>", 
+		    decl);
          break;
 
        case 2:
@@ -1371,8 +1368,8 @@ check_main_parameter_types (tree decl)
              || TREE_CODE (TREE_TYPE (type)) != POINTER_TYPE
              || (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (type)))
                  != char_type_node))
-           pedwarn (0, "second argument of %q+D should be %<char **%>",
-		     decl);
+           pedwarn (OPT_Wmain, "second argument of %q+D should be %<char **%>",
+		    decl);
          break;
 
        case 3:
@@ -1380,8 +1377,8 @@ check_main_parameter_types (tree decl)
              || TREE_CODE (TREE_TYPE (type)) != POINTER_TYPE
              || (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (type)))
                  != char_type_node))
-           pedwarn (0, "third argument of %q+D should probably be "
-		     "%<char **%>", decl);
+	   pedwarn (OPT_Wmain, "third argument of %q+D should probably be "
+		    "%<char **%>", decl);
          break;
        }
    }
@@ -1390,7 +1387,7 @@ check_main_parameter_types (tree decl)
     argument because it's only mentioned in an appendix of the
     standard.  */
   if (argct > 0 && (argct < 2 || argct > 3))
-   pedwarn (0, "%q+D takes only zero or two arguments", decl);
+    pedwarn (OPT_Wmain, "%q+D takes only zero or two arguments", decl);
 }
 
 /* True if pointers to distinct types T1 and T2 can be converted to
diff --git a/gcc/c-common.h b/gcc/c-common.h
index 0f2a359..b0abe3e 100644
--- a/gcc/c-common.h
+++ b/gcc/c-common.h
@@ -498,11 +498,6 @@ extern int flag_isoc99;
 
 extern int flag_hosted;
 
-/* Warn if main is suspicious.  */
-
-extern int warn_main;
-
-
 /* ObjC language option variables.  */
 
 
diff --git a/gcc/c-decl.c b/gcc/c-decl.c
index e55e809..7be2ca4 100644
--- a/gcc/c-decl.c
+++ b/gcc/c-decl.c
@@ -3153,8 +3153,7 @@ start_decl (struct c_declarator *declarator, struct c_declspecs *declspecs,
   if (!decl)
     return 0;
 
-  if (warn_main > 0 && TREE_CODE (decl) != FUNCTION_DECL
-      && MAIN_NAME_P (DECL_NAME (decl)))
+  if (TREE_CODE (decl) != FUNCTION_DECL && MAIN_NAME_P (DECL_NAME (decl)))
     warning (OPT_Wmain, "%q+D is usually a function", decl);
 
   if (initialized)
@@ -6207,13 +6206,13 @@ start_function (struct c_declspecs *declspecs, struct c_declarator *declarator,
     maybe_apply_pragma_weak (decl1);
 
   /* Warn for unlikely, improbable, or stupid declarations of `main'.  */
-  if (warn_main > 0 && MAIN_NAME_P (DECL_NAME (decl1)))
+  if (warn_main && MAIN_NAME_P (DECL_NAME (decl1)))
     {
       if (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (decl1)))
 	  != integer_type_node)
 	pedwarn (OPT_Wmain, "return type of %q+D is not %<int%>", decl1);
 
-      check_main_parameter_types(decl1);
+      check_main_parameter_types (decl1);
 
       if (!TREE_PUBLIC (decl1))
 	pedwarn (OPT_Wmain, "%q+D is normally a non-static function", decl1);
@@ -6672,30 +6671,18 @@ finish_function (void)
   if (DECL_RESULT (fndecl) && DECL_RESULT (fndecl) != error_mark_node)
     DECL_CONTEXT (DECL_RESULT (fndecl)) = fndecl;
 
-  if (MAIN_NAME_P (DECL_NAME (fndecl)) && flag_hosted)
-    {
-      if (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (fndecl)))
-	  != integer_type_node)
-	{
-	  /* If warn_main is 1 (-Wmain) or 2 (-Wall), we have already warned.
-	     If warn_main is -1 (-Wno-main) we don't want to be warned.  */
-	  if (!warn_main)
-	    pedwarn (0, "return type of %q+D is not %<int%>", fndecl);
-	}
-      else
-	{
-	  if (flag_isoc99)
-	    {
-	      tree stmt = c_finish_return (integer_zero_node);
-	      /* Hack.  We don't want the middle-end to warn that this return
-		 is unreachable, so we mark its location as special.  Using
-		 UNKNOWN_LOCATION has the problem that it gets clobbered in
-		 annotate_one_with_locus.  A cleaner solution might be to
-		 ensure ! should_carry_locus_p (stmt), but that needs a flag.
-	      */
-	      SET_EXPR_LOCATION (stmt, BUILTINS_LOCATION);
-	    }
-	}
+  if (MAIN_NAME_P (DECL_NAME (fndecl)) && flag_hosted
+      && TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (fndecl)))
+      == integer_type_node && flag_isoc99)
+    {
+      tree stmt = c_finish_return (integer_zero_node);
+      /* Hack.  We don't want the middle-end to warn that this return
+	 is unreachable, so we mark its location as special.  Using
+	 UNKNOWN_LOCATION has the problem that it gets clobbered in
+	 annotate_one_with_locus.  A cleaner solution might be to
+	 ensure ! should_carry_locus_p (stmt), but that needs a flag.
+      */
+      SET_EXPR_LOCATION (stmt, BUILTINS_LOCATION);
     }
 
   /* Tie off the statement tree for this function.  */
diff --git a/gcc/c-opts.c b/gcc/c-opts.c
index 83e2ed1..300bf14 100644
--- a/gcc/c-opts.c
+++ b/gcc/c-opts.c
@@ -404,9 +404,12 @@ c_common_handle_option (size_t scode, const char *arg, int value)
 	warn_uninitialized = (value ? 2 : 0);
 
       if (!c_dialect_cxx ())
-	/* We set this to 2 here, but 1 in -Wmain, so -ffreestanding
-	   can turn it off only if it's not explicit.  */
-	warn_main = value * 2;
+	{
+	  /* We set this to 2 here, but 1 in -Wmain, so -ffreestanding
+	     can turn it off only if it's not explicit.  */
+	  if (warn_main == -1)
+	    warn_main = (value ? 2 : 0);
+	}
       else
 	{
 	  /* C++-specific warnings.  */
@@ -467,13 +470,6 @@ c_common_handle_option (size_t scode, const char *arg, int value)
       cpp_opts->warn_invalid_pch = value;
       break;
 
-    case OPT_Wmain:
-      if (value)
-	warn_main = 1;
-      else
-	warn_main = -1;
-      break;
-
     case OPT_Wmissing_include_dirs:
       cpp_opts->warn_missing_include_dirs = value;
       break;
@@ -615,9 +611,6 @@ c_common_handle_option (size_t scode, const char *arg, int value)
     case OPT_fhosted:
       flag_hosted = value;
       flag_no_builtin = !value;
-      /* warn_main will be 2 if set by -Wall, 1 if set by -Wmain */
-      if (!value && warn_main == 2)
-	warn_main = 0;
       break;
 
     case OPT_fshort_double:
@@ -907,6 +900,8 @@ c_common_handle_option (size_t scode, const char *arg, int value)
 	warn_pointer_sign = 1;
       if (warn_overlength_strings == -1)
 	warn_overlength_strings = 1;
+      if (warn_main == -1)
+	warn_main = 2;
       break;
 
     case OPT_print_objc_runtime_info:
@@ -1071,6 +1066,15 @@ c_common_post_options (const char **pfilename)
   if (warn_overlength_strings == -1 || c_dialect_cxx ())
     warn_overlength_strings = 0;
 
+  /* Wmain is enabled by default in C++ but not in C.  */
+  /* Wmain is disabled by default for -ffreestanding (!flag_hosted),
+     even if -Wall was given (warn_main will be 2 if set by -Wall, 1
+     if set by -Wmain).  */
+  if (warn_main == -1)
+    warn_main = (c_dialect_cxx () && flag_hosted) ? 1 : 0;
+  else if (warn_main == 2)
+    warn_main = flag_hosted ? 1 : 0;
+
   /* In C, -Wconversion enables -Wsign-conversion (unless disabled
      through -Wno-sign-conversion). While in C++,
      -Wsign-conversion needs to be requested explicitly.  */
diff --git a/gcc/c.opt b/gcc/c.opt
index 30782d4..d33fa46 100644
--- a/gcc/c.opt
+++ b/gcc/c.opt
@@ -281,7 +281,7 @@ C ObjC C++ ObjC++ Var(warn_long_long) Init(1) Warning
 Do not warn about using \"long long\" when -pedantic
 
 Wmain
-C ObjC C++ ObjC++ Warning
+C ObjC C++ ObjC++ Var(warn_main) Init(-1) Warning
 Warn about suspicious declarations of \"main\"
 
 Wmissing-braces
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 00b3613..e34fb22 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2008-08-13  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
+
+	PR 30551
+	* decl.c (grokfndecl): Call check_main_parameters_type only if
+	-Wmain.
+
 2008-08-12  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/37087
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 6910562..3cd2511 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -6692,7 +6692,8 @@ grokfndecl (tree ctype,
 	  newtype = build_function_type (integer_type_node, oldtypeargs);
 	  TREE_TYPE (decl) = newtype;
 	}
-      check_main_parameter_types (decl);
+      if (warn_main)
+	check_main_parameter_types (decl);
     }
 
   if (ctype != NULL_TREE
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 906c6a6..56a0bda 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -2940,10 +2940,11 @@ This warning is also enabled by @option{-Wextra}.
 @item -Wmain
 @opindex Wmain
 @opindex Wno-main
-Warn if the type of @samp{main} is suspicious.  @samp{main} should be a
-function with external linkage, returning int, taking either zero
-arguments, two, or three arguments of appropriate types.
-This warning is enabled by @option{-Wall}.
+Warn if the type of @samp{main} is suspicious.  @samp{main} should be
+a function with external linkage, returning int, taking either zero
+arguments, two, or three arguments of appropriate types.  This warning
+is enabled by default in C++ and is enabled by either @option{-Wall}
+or @option{-pedantic}.
 
 @item -Wmissing-braces
 @opindex Wmissing-braces
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 951f82e..1f1890a 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,16 @@
+2008-08-13  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
+
+	PR 30551
+	* gcc.dg/pr30551.c: New.
+	* gcc.dg/pr30551-2.c: New.
+	* gcc.dg/pr30551-3.c: New.
+	* gcc.dg/pr30551-4.c: New.
+	* gcc.dg/pr30551-5.c: New.
+	* gcc.dg/pr30551-6.c: New.
+	* gcc.dg/tree-ssa/reassoc-3.c: Don't compile with -pedantic-errors.
+	* g++.dg/warn/pr30551.C: New.
+	* g++.dg/warn/pr30551-2.C: New.
+
 2008-08-13  Richard Guenther  <rguenther@suse.de>
 
 	* gcc.dg/tree-ssa/ssa-ccp-21.c: New testcase.
diff --git a/gcc/testsuite/g++.dg/warn/pr30551-2.C b/gcc/testsuite/g++.dg/warn/pr30551-2.C
new file mode 100644
index 0000000..7a4b136
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/pr30551-2.C
@@ -0,0 +1,6 @@
+// PR 30551 -Wmain is enabled by -pedantic/-pedantic-errors.
+// { dg-do compile }
+// { dg-options "-pedantic-errors" }
+
+int main(char a) {} /* { dg-error "error: first argument of .*main.* should be .int." } */
+/* { dg-error "error: .*main.* takes only zero or two arguments" "" { target *-*-* } 5 } */ 
diff --git a/gcc/testsuite/g++.dg/warn/pr30551.C b/gcc/testsuite/g++.dg/warn/pr30551.C
new file mode 100644
index 0000000..ed92487
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/pr30551.C
@@ -0,0 +1,6 @@
+// PR 30551 -Wmain is enabled by default.
+// { dg-do compile }
+// { dg-options "" }
+
+int main(char a) {} /* { dg-warning "warning: first argument of .*main.* should be .int." } */
+/* { dg-warning "warning: .*main.* takes only zero or two arguments" "" { target *-*-* } 5 } */ 
diff --git a/gcc/testsuite/gcc.dg/pr30551-2.c b/gcc/testsuite/gcc.dg/pr30551-2.c
new file mode 100644
index 0000000..fdd5df6
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr30551-2.c
@@ -0,0 +1,8 @@
+/* PR 30551 -Wmain is not enabled by default. */
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+void main(char a) {} /* { dg-bogus "first argument of .main. should be .int." } */
+/* { dg-bogus ".main. takes only zero or two arguments" "" { target *-*-* } 5 } */ 
+/* { dg-bogus "return type of .main. is not .int." "" { target *-*-* } 5 } */ 
+
diff --git a/gcc/testsuite/gcc.dg/pr30551-3.c b/gcc/testsuite/gcc.dg/pr30551-3.c
new file mode 100644
index 0000000..120d45b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr30551-3.c
@@ -0,0 +1,7 @@
+/* PR 30551 -Wmain is enabled by -pedantic-errors. */
+/* { dg-do compile } */
+/* { dg-options "-pedantic-errors" } */
+
+void main(char a) {} /* { dg-error "first argument of .main. should be .int." } */
+/* { dg-error ".main. takes only zero or two arguments" "" { target *-*-* } 5 } */ 
+/* { dg-error "return type of .main. is not .int." "" { target *-*-* } 5 } */ 
diff --git a/gcc/testsuite/gcc.dg/pr30551-4.c b/gcc/testsuite/gcc.dg/pr30551-4.c
new file mode 100644
index 0000000..4803dba
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr30551-4.c
@@ -0,0 +1,8 @@
+/* PR 30551 -Wmain is enabled by -pedantic-errors and can be disabled. */
+/* { dg-do compile } */
+/* { dg-options "-pedantic-errors -Wno-main" } */
+
+void main(char a) {} /* { dg-bogus "first argument of .main. should be .int." } */
+/* { dg-bogus ".main. takes only zero or two arguments" "" { target *-*-* } 5 } */ 
+/* { dg-bogus "return type of .main. is not .int." "" { target *-*-* } 5 } */ 
+
diff --git a/gcc/testsuite/gcc.dg/pr30551-5.c b/gcc/testsuite/gcc.dg/pr30551-5.c
new file mode 100644
index 0000000..060ed01
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr30551-5.c
@@ -0,0 +1,7 @@
+/* PR 30551 -Wmain is enabled by -pedantic and can be disabled. */
+/* { dg-do compile } */
+/* { dg-options "-pedantic -Wno-main" } */
+
+void main(char a) {} /* { dg-bogus "first argument of .main. should be .int." } */
+/* { dg-bogus ".main. takes only zero or two arguments" "" { target *-*-* } 5 } */ 
+/* { dg-bogus "return type of .main. is not .int." "" { target *-*-* } 5 } */ 
diff --git a/gcc/testsuite/gcc.dg/pr30551-6.c b/gcc/testsuite/gcc.dg/pr30551-6.c
new file mode 100644
index 0000000..9c33cd1
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr30551-6.c
@@ -0,0 +1,7 @@
+/* PR 30551 -Wmain is enabled by -pedantic. */
+/* { dg-do compile } */
+/* { dg-options "-pedantic" } */
+
+void main(char a) {} /* { dg-warning "first argument of .main. should be .int." } */
+/* { dg-warning ".main. takes only zero or two arguments" "" { target *-*-* } 5 } */ 
+/* { dg-warning "return type of .main. is not .int." "" { target *-*-* } 5 } */ 
diff --git a/gcc/testsuite/gcc.dg/pr30551.c b/gcc/testsuite/gcc.dg/pr30551.c
new file mode 100644
index 0000000..d6fdd8f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr30551.c
@@ -0,0 +1,7 @@
+/* PR 30551 -Wmain is enabled by -Wall.  */
+/* { dg-do compile } */
+/* { dg-options "-Wall" } */
+
+void main(char a) {} /* { dg-warning "first argument of .main. should be .int." } */
+/* { dg-warning ".main. takes only zero or two arguments" "" { target *-*-* } 5 } */ 
+/* { dg-warning "return type of .main. is not .int." "" { target *-*-* } 5 } */ 
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/reassoc-3.c b/gcc/testsuite/gcc.dg/tree-ssa/reassoc-3.c
index 6103c40..178e6a4 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/reassoc-3.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/reassoc-3.c
@@ -1,3 +1,4 @@
+/* { dg-options "" } */
 int main(int a, int b, int c, int d)
 {
   int e = (a & ~b) & (~c & d);