This patch fixes handling of -Werror=return-type as well as
-Wno-return-type. Currently, -Werror=return-type does not turn the
warnings into errors and -Wno-return-type does not turn off
warning/error. Now they both work as expected.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55976
Initialize warn_return_type only for C++/C++ with ObjC extensions. In C,
this allows us to differentiate between default (no option), or cases
where -Wreturn-type/-Wno-return-type are specified. Elsewhere, update
references to warn_return_type (for C) to reflect change in initialization.
Patch was successfully bootstrapped and tested on x86_64-linux.
--Dave
/c
2018-04-22 David Pagan <dave.pa...@oracle.com>
PR c/55976
* c-decl.c (grokdeclarator): Update check for return type warnings.
(start_function): Likewise.
(finish_function): Likewise.
* c-typeck.c (c_finish_return): Update check for return type warnings.
Pass OPT_Wreturn_type to pedwarn when appropriate.
* c-opts.c (c_common_post_options): Set default for warn_return_type
for C++/C++ with ObjC extensions only. For C, makes it possible to
differentiate between default (no option), -Wreturn-type, and
-Wno-return-type.
/testsuite
2018-04-22 David Pagan <dave.pa...@oracle.com>
PR c/55976
* gcc.dg/noncompile/pr55976-1.c: New test.
* gcc.dg/noncompile/pr55976-2.c: New test.
Index: gcc/c/c-decl.c
===================================================================
--- gcc/c/c-decl.c (revision 259017)
+++ gcc/c/c-decl.c (working copy)
@@ -5745,7 +5745,7 @@ grokdeclarator (const struct c_declarator *declara
/* Issue a warning if this is an ISO C 99 program or if
-Wreturn-type and this is a function, or if -Wimplicit;
prefer the former warning since it is more explicit. */
- if ((warn_implicit_int || warn_return_type || flag_isoc99)
+ if ((warn_implicit_int || warn_return_type > 0 || flag_isoc99)
&& funcdef_flag)
warn_about_return_type = 1;
else
@@ -8739,7 +8739,7 @@ start_function (struct c_declspecs *declspecs, str
if (warn_about_return_type)
warn_defaults_to (loc, flag_isoc99 ? OPT_Wimplicit_int
- : (warn_return_type ? OPT_Wreturn_type
+ : (warn_return_type > 0 ? OPT_Wreturn_type
: OPT_Wimplicit_int),
"return type defaults to %<int%>");
@@ -9450,8 +9450,9 @@ finish_function (void)
finish_fname_decls ();
- /* Complain if there's just no return statement. */
- if (warn_return_type
+ /* Complain if there's no return statement only if option specified on
+ command line. */
+ if (warn_return_type > 0
&& TREE_CODE (TREE_TYPE (TREE_TYPE (fndecl))) != VOID_TYPE
&& !current_function_returns_value && !current_function_returns_null
/* Don't complain if we are no-return. */
Index: gcc/c/c-typeck.c
===================================================================
--- gcc/c/c-typeck.c (revision 259017)
+++ gcc/c/c-typeck.c (working copy)
@@ -10129,13 +10129,13 @@ c_finish_return (location_t loc, tree retval, tree
if (!retval)
{
current_function_returns_null = 1;
- if ((warn_return_type || flag_isoc99)
+ if ((warn_return_type >= 0 || flag_isoc99)
&& valtype != NULL_TREE && TREE_CODE (valtype) != VOID_TYPE)
{
bool warned_here;
if (flag_isoc99)
warned_here = pedwarn
- (loc, 0,
+ (loc, warn_return_type >= 0 ? OPT_Wreturn_type : 0,
"%<return%> with no value, in function returning non-void");
else
warned_here = warning_at
@@ -10153,7 +10153,7 @@ c_finish_return (location_t loc, tree retval, tree
bool warned_here;
if (TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
warned_here = pedwarn
- (xloc, 0,
+ (xloc, warn_return_type >= 0 ? OPT_Wreturn_type : 0,
"%<return%> with a value, in function returning void");
else
warned_here = pedwarn
Index: gcc/c-family/c-opts.c
===================================================================
--- gcc/c-family/c-opts.c (revision 259017)
+++ gcc/c-family/c-opts.c (working copy)
@@ -994,8 +994,9 @@ c_common_post_options (const char **pfilename)
flag_extern_tls_init = 1;
}
- if (warn_return_type == -1)
- warn_return_type = c_dialect_cxx ();
+ /* Enable by default only for C++ and C++ with ObjC extensions. */
+ if (warn_return_type == -1 && c_dialect_cxx ())
+ warn_return_type = 1;
if (num_in_fnames > 1)
error ("too many filenames given. Type %s --help for usage",
Index: gcc/testsuite/gcc.dg/noncompile/pr55976-1.c
===================================================================
--- gcc/testsuite/gcc.dg/noncompile/pr55976-1.c (revision 0)
+++ gcc/testsuite/gcc.dg/noncompile/pr55976-1.c (working copy)
@@ -0,0 +1,14 @@
+/* PR c/55976 */
+/* { dg-do compile } */
+/* { dg-options "-Werror=return-type" } */
+
+/* Verify warnings for return type become errors. */
+
+void t () { return 1; } /* { dg-error "return" "function returning void" } */
+int b () { return; } /* { dg-error "return" "function returning non-void" } */
+
+int main()
+{
+ t(); b();
+ return 0;
+}
Index: gcc/testsuite/gcc.dg/noncompile/pr55976-2.c
===================================================================
--- gcc/testsuite/gcc.dg/noncompile/pr55976-2.c (revision 0)
+++ gcc/testsuite/gcc.dg/noncompile/pr55976-2.c (working copy)
@@ -0,0 +1,16 @@
+/* PR c/55976 */
+/* { dg-do compile } */
+/* { dg-options "-Wno-return-type" } */
+
+/* Verify that -Wno-return-type turns off warnings about function return
+ type. */
+
+void t () { return 1; } /* normally generates function returning void */
+int b () { return; } /* normally generates function returning non-void */
+
+int main()
+{
+ t (); b ();
+ return 0;
+}
+
