| Message ID | ccc21947-dd32-0f0a-8aa3-70ae9e255423@oracle.com |
|---|---|
| State | New |
| Headers | show |
| Series | c/55976 -Werror=return-type should error on returning a value from a void function | expand |
Ping for the following C patch sent on 4/22/2018 https://gcc.gnu.org/ml/gcc-patches/2018-04/msg01034.html Thanks, --Dave ========== On 04/22/2018 12:17 PM, dave.pagan@oracle.com wrote: > 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 >
On 04/22/2018 01:17 PM, dave.pagan@oracle.com wrote: > 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 > > > CL-55976 > > > /c > 2018-04-22 David Pagan <dave.pagan@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.pagan@oracle.com> > > PR c/55976 > * gcc.dg/noncompile/pr55976-1.c: New test. > * gcc.dg/noncompile/pr55976-2.c: New test. THanks. Installed on the trunk. Sorry for the long delay, Jeff
On Wed, May 30, 2018 at 3:56 PM, Jeff Law <law@redhat.com> wrote: > On 04/22/2018 01:17 PM, dave.pagan@oracle.com wrote: >> 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 >> >> >> CL-55976 >> >> >> /c >> 2018-04-22 David Pagan <dave.pagan@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.pagan@oracle.com> >> >> PR c/55976 >> * gcc.dg/noncompile/pr55976-1.c: New test. >> * gcc.dg/noncompile/pr55976-2.c: New test. > THanks. Installed on the trunk. > On x86, I got FAIL: gcc.dg/noncompile/pr55976-1.c -O0 (test for excess errors) FAIL: gcc.dg/noncompile/pr55976-1.c -O1 (test for excess errors) FAIL: gcc.dg/noncompile/pr55976-1.c -O2 -flto -fno-use-linker-plugin -flto-partition=none (test for excess errors) FAIL: gcc.dg/noncompile/pr55976-1.c -O2 -flto -fuse-linker-plugin -fno-fat-lto-objects (test for excess errors) FAIL: gcc.dg/noncompile/pr55976-1.c -O2 (test for excess errors) FAIL: gcc.dg/noncompile/pr55976-1.c -O3 -g (test for excess errors) FAIL: gcc.dg/noncompile/pr55976-1.c -Os (test for excess errors) [hjl@gnu-skx-1 testsuite]$ /export/ssd/git/gcc-test-native/bld/gcc/xgcc -B/export/ssd/git/gcc-test-native/bld/gcc/ /export/ssd/git/gcc-test-native/src-trunk/gcc/testsuite/gcc.dg/noncompile/pr55976-1.c -mx32 -B/export/ssd/git/gcc-test-native/bld/x86_64-pc-linux-gnu/32/libmpx/ -B/export/ssd/git/gcc-test-native/bld/x86_64-pc-linux-gnu/32/libmpx/mpxrt -L/export/ssd/git/gcc-test-native/bld/x86_64-pc-linux-gnu/32/libmpx/mpxrt/.libs -B/export/ssd/git/gcc-test-native/bld/x86_64-pc-linux-gnu/32/libmpx/ -B/export/ssd/git/gcc-test-native/bld/x86_64-pc-linux-gnu/32/libmpx/mpxwrap -L/export/ssd/git/gcc-test-native/bld/x86_64-pc-linux-gnu/32/libmpx/mpxwrap/.libs -fno-diagnostics-show-caret -fdiagnostics-color=never -O2 -flto -fuse-linker-plugin -fno-fat-lto-objects -Werror=return-type -S -o pr55976-1.s /export/ssd/git/gcc-test-native/src-trunk/gcc/testsuite/gcc.dg/noncompile/pr55976-1.c: In function \u2018t\u2019: /export/ssd/git/gcc-test-native/src-trunk/gcc/testsuite/gcc.dg/noncompile/pr55976-1.c:7:20: error: \u2018return\u2019 with a value, in function returning void [-Werror=return-type] /export/ssd/git/gcc-test-native/src-trunk/gcc/testsuite/gcc.dg/noncompile/pr55976-1.c:7:6: note: declared here /export/ssd/git/gcc-test-native/src-trunk/gcc/testsuite/gcc.dg/noncompile/pr55976-1.c: In function \u2018b\u2019: /export/ssd/git/gcc-test-native/src-trunk/gcc/testsuite/gcc.dg/noncompile/pr55976-1.c:8:12: error: \u2018return\u2019 with no value, in function returning non-void [-Werror=return-type] /export/ssd/git/gcc-test-native/src-trunk/gcc/testsuite/gcc.dg/noncompile/pr55976-1.c:8:5: note: declared here cc1: some warnings being treated as errors [hjl@gnu-skx-1 testsuite]$
Thanks for pointing this out. I'll check out what's going on and fix the issue --Dave On 05/31/2018 05:53 AM, H.J. Lu wrote: > On Wed, May 30, 2018 at 3:56 PM, Jeff Law <law@redhat.com> wrote: >> On 04/22/2018 01:17 PM, dave.pagan@oracle.com wrote: >>> 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 >>> >>> >>> CL-55976 >>> >>> >>> /c >>> 2018-04-22 David Pagan <dave.pagan@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.pagan@oracle.com> >>> >>> PR c/55976 >>> * gcc.dg/noncompile/pr55976-1.c: New test. >>> * gcc.dg/noncompile/pr55976-2.c: New test. >> THanks. Installed on the trunk. >> > On x86, I got > > FAIL: gcc.dg/noncompile/pr55976-1.c -O0 (test for excess errors) > FAIL: gcc.dg/noncompile/pr55976-1.c -O1 (test for excess errors) > FAIL: gcc.dg/noncompile/pr55976-1.c -O2 -flto -fno-use-linker-plugin > -flto-partition=none (test for excess errors) > FAIL: gcc.dg/noncompile/pr55976-1.c -O2 -flto -fuse-linker-plugin > -fno-fat-lto-objects (test for excess errors) > FAIL: gcc.dg/noncompile/pr55976-1.c -O2 (test for excess errors) > FAIL: gcc.dg/noncompile/pr55976-1.c -O3 -g (test for excess errors) > FAIL: gcc.dg/noncompile/pr55976-1.c -Os (test for excess errors) > > [hjl@gnu-skx-1 testsuite]$ > /export/ssd/git/gcc-test-native/bld/gcc/xgcc > -B/export/ssd/git/gcc-test-native/bld/gcc/ > /export/ssd/git/gcc-test-native/src-trunk/gcc/testsuite/gcc.dg/noncompile/pr55976-1.c > -mx32 -B/export/ssd/git/gcc-test-native/bld/x86_64-pc-linux-gnu/32/libmpx/ > -B/export/ssd/git/gcc-test-native/bld/x86_64-pc-linux-gnu/32/libmpx/mpxrt > -L/export/ssd/git/gcc-test-native/bld/x86_64-pc-linux-gnu/32/libmpx/mpxrt/.libs > -B/export/ssd/git/gcc-test-native/bld/x86_64-pc-linux-gnu/32/libmpx/ > -B/export/ssd/git/gcc-test-native/bld/x86_64-pc-linux-gnu/32/libmpx/mpxwrap > -L/export/ssd/git/gcc-test-native/bld/x86_64-pc-linux-gnu/32/libmpx/mpxwrap/.libs > -fno-diagnostics-show-caret -fdiagnostics-color=never -O2 -flto > -fuse-linker-plugin -fno-fat-lto-objects -Werror=return-type -S -o > pr55976-1.s > /export/ssd/git/gcc-test-native/src-trunk/gcc/testsuite/gcc.dg/noncompile/pr55976-1.c: > In function \u2018t\u2019: > /export/ssd/git/gcc-test-native/src-trunk/gcc/testsuite/gcc.dg/noncompile/pr55976-1.c:7:20: > error: \u2018return\u2019 with a value, in function returning void > [-Werror=return-type] > /export/ssd/git/gcc-test-native/src-trunk/gcc/testsuite/gcc.dg/noncompile/pr55976-1.c:7:6: > note: declared here > /export/ssd/git/gcc-test-native/src-trunk/gcc/testsuite/gcc.dg/noncompile/pr55976-1.c: > In function \u2018b\u2019: > /export/ssd/git/gcc-test-native/src-trunk/gcc/testsuite/gcc.dg/noncompile/pr55976-1.c:8:12: > error: \u2018return\u2019 with no value, in function returning > non-void [-Werror=return-type] > /export/ssd/git/gcc-test-native/src-trunk/gcc/testsuite/gcc.dg/noncompile/pr55976-1.c:8:5: > note: declared here > cc1: some warnings being treated as errors > [hjl@gnu-skx-1 testsuite]$ >
On 06/01/2018 11:08 PM, dave.pagan@oracle.com wrote: > Thanks for pointing this out. I'll check out what's going on and fix the issue > > --Dave Hi. Difference is in between C and C++ FEs: marxin@marxinbox:/dev/shm/objdir/gcc> ./xgcc -B. /home/marxin/Programming/gcc/gcc/testsuite/gcc.dg/noncompile/pr55976-1.c /home/marxin/Programming/gcc/gcc/testsuite/gcc.dg/noncompile/pr55976-1.c: In function ‘t’: /home/marxin/Programming/gcc/gcc/testsuite/gcc.dg/noncompile/pr55976-1.c:7:20: warning: ‘return’ with a value, in function returning void void t () { return 1; } /* { dg-error "return" "function returning void" } */ ^ /home/marxin/Programming/gcc/gcc/testsuite/gcc.dg/noncompile/pr55976-1.c:7:6: note: declared here void t () { return 1; } /* { dg-error "return" "function returning void" } */ ^ /home/marxin/Programming/gcc/gcc/testsuite/gcc.dg/noncompile/pr55976-1.c: In function ‘b’: /home/marxin/Programming/gcc/gcc/testsuite/gcc.dg/noncompile/pr55976-1.c:8:12: warning: ‘return’ with no value, in function returning non-void int b () { return; } /* { dg-error "return" "function returning non-void" } */ ^~~~~~ /home/marxin/Programming/gcc/gcc/testsuite/gcc.dg/noncompile/pr55976-1.c:8:5: note: declared here int b () { return; } /* { dg-error "return" "function returning non-void" } */ ^ marxin@marxinbox:/dev/shm/objdir/gcc> ./xg++ -B. /home/marxin/Programming/gcc/gcc/testsuite/gcc.dg/noncompile/pr55976-1.c /home/marxin/Programming/gcc/gcc/testsuite/gcc.dg/noncompile/pr55976-1.c: In function ‘void t()’: /home/marxin/Programming/gcc/gcc/testsuite/gcc.dg/noncompile/pr55976-1.c:7:20: error: return-statement with a value, in function returning ‘void’ [-fpermissive] void t () { return 1; } /* { dg-error "return" "function returning void" } */ ^ /home/marxin/Programming/gcc/gcc/testsuite/gcc.dg/noncompile/pr55976-1.c: In function ‘int b()’: /home/marxin/Programming/gcc/gcc/testsuite/gcc.dg/noncompile/pr55976-1.c:8:12: error: return-statement with no value, in function returning ‘int’ [-fpermissive] int b () { return; } /* { dg-error "return" "function returning non-void" } */ ^~~~~~ Martin
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; +} +