Hi Jason, Thanks for the reply. I'm a little bit overwhelmed with university at the moment, would it be ok if I delay implementing this a little bit?
best regards, Julian On Tue, Jun 4, 2024 at 1:04 AM Jason Merrill <ja...@redhat.com> wrote: > > On 6/1/24 11:31, Julian Waters wrote: > > Hi Jason, > > > > Thanks for the reply! I'll address your comments soon. I have a > > question, if there is an option defined in c.opt as an Enum, like > > fstrong-eval-order, and the -no variant of the option is passed, would > > the Var somehow reflect the negated option? Eg > > > > Winvalid-noreturn= > > C ObjC C++ ObjC++ Var(warn_invalid_noreturn) Joined > > Enum(invalid_noreturn) Warning > > > > Enum > > Name(invalid_noreturn) Type(int) > > > > EnumValue > > Enum(invalid_noreturn) String(explicit) Value(0) > > -fstrong-eval-order has > > fstrong-eval-order > C++ ObjC++ Common Alias(fstrong-eval-order=, all, none) > > to represent that plain -fstrong-eval-order is equivalent to > -fstrong-eval-order=all, and -fno-strong-eval-order is equivalent to =none. > > > Would warn_invalid_noreturn then != 0 if > > -Wno-invalid-noreturn=explicit is passed? Or is there a way to make a > > warning call depend on 2 different OPT_ entries? > > Typically = options will specify RejectNegative so the driver will > reject e.g. -Wno-invalid-noreturn=explicit. > > Jason > > > best regards, > > Julian > > > > On Sat, Jun 1, 2024 at 4:57 AM Jason Merrill <ja...@redhat.com> wrote: > >> > >> On 5/29/24 09:58, Julian Waters wrote: > >>> Currently, gcc warns about noreturn marked functions that return both > >>> explicitly and implicitly, with no way to turn this warning off. clang > >>> does have an option for these classes of warnings, -Winvalid-noreturn. > >>> However, we can do better. Instead of just having 1 option that switches > >>> the warnings for both on and off, we can define an extra layer of > >>> granularity, and have a separate options for implicit returns and > >>> explicit returns, as in -Winvalid-return=explicit and > >>> -Winvalid-noreturn=implicit. This patch adds both to gcc, for > >>> compatibility with clang. > >> > >> Thanks! > >> > >>> Do note that I am relatively new to gcc's codebase, and as such couldn't > >>> figure out how to cleanly define a general -Winvalid-noreturn warning > >>> that switch both on and off, for better compatibility with clang. If > >>> someone should point out how to do so, I'll happily rewrite my patch. > >> > >> See -fstrong-eval-order for an example of an option that can be used > >> with or without =arg. > >> > >>> I also do not have write access to gcc, and will need help pushing this > >>> patch once the green light is given > >> > >> Good to know, I can take care of that. > >> > >>> best regards, > >>> Julian > >>> > >>> gcc/c-family/ChangeLog: > >>> > >>> * c.opt: Introduce -Winvalid-noreturn=explicit and > >>> -Winvalid-noreturn=implicit > >>> > >>> gcc/ChangeLog: > >>> > >>> * tree-cfg.cc (pass_warn_function_return::execute): Use it > >>> > >>> gcc/c/ChangeLog: > >>> > >>> * c-typeck.cc (c_finish_return): Use it > >>> * gimple-parser.cc (c_finish_gimple_return): Use it > >>> > >>> gcc/config/mingw/ChangeLog: > >>> > >>> * mingw32.h (EXTRA_OS_CPP_BUILTINS): Fix semicolons > >>> > >>> gcc/cp/ChangeLog: > >>> > >>> * coroutines.cc (finish_co_return_stmt): Use it > >>> * typeck.cc (check_return_expr): Use it > >>> > >>> gcc/doc/ChangeLog: > >>> > >>> * invoke.texi: Document new options > >>> > >>> From 4daf884f8bbc1e318ba93121a6fdf4139da80b64 Mon Sep 17 00:00:00 2001 > >>> From: TheShermanTanker <tanksherma...@gmail.com> > >>> Date: Wed, 29 May 2024 21:32:08 +0800 > >>> Subject: [PATCH] Introduce the -Winvalid-noreturn flag from clang with > >>> extra > >>> tuneability > >> > >> The rationale and ChangeLog entries should be part of the commit message > >> (and so the git format-patch output). > >> > >>> > >>> Signed-off-by: TheShermanTanker <tanksherma...@gmail.com> > >> > >> A DCO sign-off can't use a pseudonym, sorry; please either sign off > >> using your real name or file a copyright assignment for the pseudonym > >> with the FSF. > >> > >> See https://gcc.gnu.org/contribute.html#legal for more detail. > >> > >>> --- > >>> gcc/c-family/c.opt | 8 ++++++++ > >>> gcc/c/c-typeck.cc | 2 +- > >>> gcc/c/gimple-parser.cc | 2 +- > >>> gcc/config/mingw/mingw32.h | 6 +++--- > >>> gcc/cp/coroutines.cc | 2 +- > >>> gcc/cp/typeck.cc | 2 +- > >>> gcc/doc/invoke.texi | 13 +++++++++++++ > >>> gcc/tree-cfg.cc | 2 +- > >>> 8 files changed, 29 insertions(+), 8 deletions(-) > >>> > >>> diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt > >>> index fb34c3b7031..32a2859fdcc 100644 > >>> --- a/gcc/c-family/c.opt > >>> +++ b/gcc/c-family/c.opt > >>> @@ -886,6 +886,14 @@ Winvalid-constexpr > >>> C++ ObjC++ Var(warn_invalid_constexpr) Init(-1) Warning > >>> Warn when a function never produces a constant expression. > >>> > >>> +Winvalid-noreturn=explicit > >>> +C ObjC C++ ObjC++ Warning > >>> +Warn when a function marked noreturn returns explicitly. > >>> + > >>> +Winvalid-noreturn=implicit > >>> +C ObjC C++ ObjC++ Warning > >>> +Warn when a function marked noreturn returns implicitly. > >>> + > >>> Winvalid-offsetof > >>> C++ ObjC++ Var(warn_invalid_offsetof) Init(1) Warning > >>> Warn about invalid uses of the \"offsetof\" macro. > >>> diff --git a/gcc/c/c-typeck.cc b/gcc/c/c-typeck.cc > >>> index ad4c7add562..1941fbc44cb 100644 > >>> --- a/gcc/c/c-typeck.cc > >>> +++ b/gcc/c/c-typeck.cc > >>> @@ -11468,7 +11468,7 @@ c_finish_return (location_t loc, tree retval, > >>> tree origtype) > >>> location_t xloc = expansion_point_location_if_in_system_header (loc); > >>> > >>> if (TREE_THIS_VOLATILE (current_function_decl)) > >>> - warning_at (xloc, 0, > >>> + warning_at (xloc, OPT_Winvalid_noreturn_explicit, > >>> "function declared %<noreturn%> has a %<return%> > >>> statement"); > >>> > >>> if (retval) > >>> diff --git a/gcc/c/gimple-parser.cc b/gcc/c/gimple-parser.cc > >>> index d156d83cd37..1acaf75f844 100644 > >>> --- a/gcc/c/gimple-parser.cc > >>> +++ b/gcc/c/gimple-parser.cc > >>> @@ -2593,7 +2593,7 @@ c_finish_gimple_return (location_t loc, tree retval) > >>> location_t xloc = expansion_point_location_if_in_system_header (loc); > >>> > >>> if (TREE_THIS_VOLATILE (current_function_decl)) > >>> - warning_at (xloc, 0, > >>> + warning_at (xloc, OPT_Winvalid_noreturn_explicit, > >>> "function declared %<noreturn%> has a %<return%> > >>> statement"); > >>> > >>> if (! retval) > >>> diff --git a/gcc/config/mingw/mingw32.h b/gcc/config/mingw/mingw32.h > >>> index fa6e307476c..a69926133b1 100644 > >>> --- a/gcc/config/mingw/mingw32.h > >>> +++ b/gcc/config/mingw/mingw32.h > >>> @@ -35,9 +35,9 @@ along with GCC; see the file COPYING3. If not see > >>> | MASK_MS_BITFIELD_LAYOUT) > >>> > >>> #ifdef TARGET_USING_MCFGTHREAD > >>> -#define DEFINE_THREAD_MODEL builtin_define ("__USING_MCFGTHREAD__"); > >>> +#define DEFINE_THREAD_MODEL builtin_define ("__USING_MCFGTHREAD__") > >>> #elif defined(TARGET_USE_PTHREAD_BY_DEFAULT) > >>> -#define DEFINE_THREAD_MODEL builtin_define ("__USING_POSIXTHREAD__"); > >>> +#define DEFINE_THREAD_MODEL builtin_define ("__USING_POSIXTHREAD__") > >>> #else > >>> #define DEFINE_THREAD_MODEL > >>> #endif > >>> @@ -60,7 +60,7 @@ along with GCC; see the file COPYING3. If not see > >>> builtin_define_std ("WIN64"); \ > >>> builtin_define ("_WIN64"); \ > >>> } \ > >>> - DEFINE_THREAD_MODEL \ > >>> + DEFINE_THREAD_MODEL; \ > >>> } \ > >>> while (0) > >>> > >>> diff --git a/gcc/cp/coroutines.cc b/gcc/cp/coroutines.cc > >>> index 97bc211ff67..53e56bd4959 100644 > >>> --- a/gcc/cp/coroutines.cc > >>> +++ b/gcc/cp/coroutines.cc > >>> @@ -1375,7 +1375,7 @@ finish_co_return_stmt (location_t kw, tree expr) > >>> > >>> /* Makes no sense for a co-routine really. */ > >>> if (TREE_THIS_VOLATILE (current_function_decl)) > >>> - warning_at (kw, 0, > >>> + warning_at (kw, OPT_Winvalid_noreturn_explicit, > >>> "function declared %<noreturn%> has a" > >>> " %<co_return%> statement"); > >>> > >>> diff --git a/gcc/cp/typeck.cc b/gcc/cp/typeck.cc > >>> index 1b7a31d32f3..74cc59bfb87 100644 > >>> --- a/gcc/cp/typeck.cc > >>> +++ b/gcc/cp/typeck.cc > >>> @@ -11062,7 +11062,7 @@ check_return_expr (tree retval, bool *no_warning, > >>> bool *dangling) > >>> (This is a G++ extension, used to get better code for functions > >>> that call the `volatile' function.) */ > >>> if (TREE_THIS_VOLATILE (current_function_decl)) > >>> - warning (0, "function declared %<noreturn%> has a %<return%> > >>> statement"); > >>> + warning (OPT_Winvalid_noreturn_explicit, "function declared > >>> %<noreturn%> has a %<return%> statement"); > >>> > >>> /* Check for various simple errors. */ > >>> if (DECL_DESTRUCTOR_P (current_function_decl)) > >>> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi > >>> index 2cba380718b..27d880fd4f0 100644 > >>> --- a/gcc/doc/invoke.texi > >>> +++ b/gcc/doc/invoke.texi > >>> @@ -376,6 +376,7 @@ Objective-C and Objective-C++ Dialects}. > >>> -Winfinite-recursion > >>> -Winit-self -Winline -Wno-int-conversion -Wint-in-bool-context > >>> -Wno-int-to-pointer-cast -Wno-invalid-memory-model > >>> +-Winvalid-noreturn=explicit -Winvalid-noreturn=implicit > >>> -Winvalid-pch -Winvalid-utf8 -Wno-unicode -Wjump-misses-init > >>> -Wlarger-than=@var{byte-size} -Wlogical-not-parentheses -Wlogical-op > >>> -Wlong-long -Wno-lto-type-mismatch -Wmain -Wmaybe-uninitialized > >>> @@ -10482,6 +10483,18 @@ an error. @option{Wint-to-pointer-cast} is > >>> enabled by default. > >>> Suppress warnings from casts from a pointer to an integer type of a > >>> different size. > >>> > >>> +@opindex Winvalid-noreturn=explicit > >>> +@opindex Wno-invalid-noreturn=explicit > >>> +@item -Winvalid-noreturn=explicit > >>> +Warn if a function marked noreturn returns explicitly, that is, it > >>> +contains a return statement. > >>> + > >>> +@opindex Winvalid-noreturn=implicit > >>> +@opindex Wno-invalid-noreturn=implicit > >>> +@item -Winvalid-noreturn=implicit > >>> +Warn if a function marked noreturn returns implicitly, that is, it > >>> +has a path in its control flow that can reach the end of its body. > >>> + > >>> @opindex Winvalid-pch > >>> @opindex Wno-invalid-pch > >>> @item -Winvalid-pch > >>> diff --git a/gcc/tree-cfg.cc b/gcc/tree-cfg.cc > >>> index 7fb7b92966b..cfe91038dd1 100644 > >>> --- a/gcc/tree-cfg.cc > >>> +++ b/gcc/tree-cfg.cc > >>> @@ -9817,7 +9817,7 @@ pass_warn_function_return::execute (function *fun) > >>> } > >>> if (location == UNKNOWN_LOCATION) > >>> location = cfun->function_end_locus; > >>> - warning_at (location, 0, "%<noreturn%> function does return"); > >>> + warning_at (location, OPT_Winvalid_noreturn_implicit, > >>> "%<noreturn%> function does return"); > >>> } > >>> > >>> /* If we see "return;" in some basic block, then we do reach the end > >> > > >
