[PATCH] D33102: [clang] Implement -Wcast-qual for C++
Roman Lebedev via cfe-commits
cfe-commits at lists.llvm.org
Fri Jun 9 13:39:20 PDT 2017
On Fri, Jun 9, 2017 at 11:28 PM, David Blaikie <dblaikie at gmail.com> wrote:
> Looks all good
OK, thank you.
> please commit whenever you're ready - if you don't have
> commit access, I (or anyone else with commit access) can commit this for
> you.
Will re-test and commit in +~12 hours.
> On Tue, Jun 6, 2017 at 1:57 PM Roman Lebedev <lebedev.ri at gmail.com> wrote:
>>
>> On Tue, Jun 6, 2017 at 8:52 PM, David Blaikie <dblaikie at gmail.com> wrote:
>> >
>> >
>> > On Tue, Jun 6, 2017 at 3:59 AM Roman Lebedev via Phabricator
>> > <reviews at reviews.llvm.org> wrote:
>> >>
>> >> lebedev.ri added a comment.
>> >>
>> >> In https://reviews.llvm.org/D33102#773296, @dblaikie wrote:
>> >>
>> >> > I still feel like that's more testing than would be ideal (does the
>> >> > context of the cast matter? Wether it's dereferenced, a struct member
>> >> > access, assigned, initialized, etc - it doesn't look like it from the
>> >> > code,
>> >> > etc).
>> >>
>> >>
>> >> Looking at the `CastsAwayConstness()` function in
>> >> lib/Sema/SemaCast.cpp:
>> >>
>> >> https://github.com/llvm-mirror/clang/blob/432ed0e4a6d58f7dda8992a167aad43bc91f76c6/lib/Sema/SemaCast.cpp#L505-L510
>> >> You can see that it asserts that the pointer is one of three types. So
>> >> i
>> >> think it it is best to have maybe slightly overlapping test coverage
>> >> here,
>> >> rather than be surprised one day that such trivial cases no longer
>> >> warn...
>> >>
>> >> > But sure. Could you also (manually, I guess) confirm that this
>> >> > matches
>> >> > GCC's cast-qual behavior (insofar as the warning fires in the same
>> >> > situations). If there are any deviations, let's chat about them.
>> >>
>> >> Sure.
>> >>
>> >> 1. Gcc produces the same //count// of the warnings:
>> >>
>> >> $ pwd
>> >> llvm/tools/clang/test
>> >> $ grep -o "expected-warning" Sema/warn-cast-qual.c | wc -l
>> >> 14
>> >> $ gcc -x c -fsyntax-only -Wcast-qual -c Sema/warn-cast-qual.c 2>&1 |
>> >> grep ": warning: " | wc -l
>> >> 14
>> >> $ gcc -x c++ -fsyntax-only -Wcast-qual -c Sema/warn-cast-qual.c 2>&1
>> >> |
>> >> grep ": warning: " | wc -l
>> >> 14
>> >> $ grep -o "expected-warning" SemaCXX/warn-cast-qual.cpp | wc -l
>> >> 39
>> >> $ gcc -x c++ -fsyntax-only -Wcast-qual -c SemaCXX/warn-cast-qual.cpp
>> >> 2>&1 | grep ": warning: " | wc -l
>> >> 39
>> >>
>> >> 2. I'm not quite sure how to non-manually compare the warnings, so i'll
>> >> just show the gcc output on these three cases. Since the clang warnings
>> >> are
>> >> appended as comments at the end of the each line that should warn,
>> >> visual
>> >> comparison is possible:
>>
>> > Works for the positive cases, not the negative ones. (though if the
>> > counts
>> > are exactly the same, then so long as there are no false positives there
>> > aren't any false negatives either)
>> Yes, fair enough, i do not have anything to add here.
>>
>> >>
>> >>
>> >> 2.1.
>> >>
>> >> $ gcc -x c -fsyntax-only -Wcast-qual -c Sema/warn-cast-qual.c
>> >> Sema/warn-cast-qual.c: In function ‘foo’:
>> >> Sema/warn-cast-qual.c:9:13: warning: cast discards ‘const’ qualifier
>> >> from pointer target type [-Wcast-qual]
>> >> char *y = (char *)ptr; // expected-warning {{cast from 'const char
>> >> *'
>> >> to 'char *' drops const qualifier}}
>> >> ^
>> >> Sema/warn-cast-qual.c:10:15: warning: cast discards ‘const’ qualifier
>> >> from pointer target type [-Wcast-qual]
>> >> char **y1 = (char **)ptrptr; // expected-warning {{cast from
>> >> 'const
>> >> char *const' to 'char *' drops const qualifier}}
>> >> ^
>> >> Sema/warn-cast-qual.c:11:21: warning: cast discards ‘const’ qualifier
>> >> from pointer target type [-Wcast-qual]
>> >> const char **y2 = (const char **)ptrptr; // expected-warning
>> >> {{cast
>> >> from 'const char *const *' to 'const char **' drops const qualifier}}
>> >> ^
>> >> Sema/warn-cast-qual.c:14:14: warning: cast discards ‘const’ qualifier
>> >> from pointer target type [-Wcast-qual]
>> >> char *z1 = (char *)(const void *)ptr; // expected-warning {{cast
>> >> from
>> >> 'const void *' to 'char *' drops const qualifier}}
>> >> ^
>> >> Sema/warn-cast-qual.c:17:16: warning: cast discards ‘volatile’
>> >> qualifier
>> >> from pointer target type [-Wcast-qual]
>> >> char *vol2 = (char *)vol; // expected-warning {{cast from
>> >> 'volatile
>> >> char *' to 'char *' drops volatile qualifier}}
>> >> ^
>> >> Sema/warn-cast-qual.c:19:17: warning: cast discards ‘const volatile’
>> >> qualifier from pointer target type [-Wcast-qual]
>> >> char *volc2 = (char *)volc; // expected-warning {{cast from 'const
>> >> volatile char *' to 'char *' drops const and volatile qualifiers}}
>> >> ^
>> >> Sema/warn-cast-qual.c:22:28: warning: to be safe all intermediate
>> >> pointers in cast from ‘int **’ to ‘const int **’ must be ‘const’
>> >> qualified
>> >> [-Wcast-qual]
>> >> const int **intptrptrc = (const int **)intptrptr; //
>> >> expected-warning
>> >> {{cast from 'int **' to 'const int **' must have all intermediate
>> >> pointers
>> >> const qualified}}
>> >> ^
>> >> Sema/warn-cast-qual.c:23:31: warning: to be safe all intermediate
>> >> pointers in cast from ‘int **’ to ‘volatile int **’ must be ‘const’
>> >> qualified [-Wcast-qual]
>> >> volatile int **intptrptrv = (volatile int **)intptrptr; //
>> >> expected-warning {{cast from 'int **' to 'volatile int **' must have
>> >> all
>> >> intermediate pointers const qualified}}
>> >> ^
>> >> Sema/warn-cast-qual.c:29:23: warning: cast discards ‘const’ qualifier
>> >> from pointer target type [-Wcast-qual]
>> >> char **charptrptr = (char **)charptrptrc; // expected-warning
>> >> {{cast
>> >> from 'const char *' to 'char *' drops const qualifier}}
>> >> ^
>> >> Sema/warn-cast-qual.c:32:19: warning: cast discards ‘const’ qualifier
>> >> from pointer target type [-Wcast-qual]
>> >> char *charptr = (char *)constcharptr; // expected-warning {{cast
>> >> from
>> >> 'const char *' to 'char *' drops const qualifier}}
>> >> ^
>> >> Sema/warn-cast-qual.c:33:31: warning: cast discards ‘const’ qualifier
>> >> from pointer target type [-Wcast-qual]
>> >> const char *constcharptr2 = (char *)constcharptr; //
>> >> expected-warning
>> >> {{cast from 'const char *' to 'char *' drops const qualifier}}
>> >> ^
>> >> Sema/warn-cast-qual.c: In function ‘bar_0’:
>> >> Sema/warn-cast-qual.c:45:4: warning: cast discards ‘const’ qualifier
>> >> from pointer target type [-Wcast-qual]
>> >> *(int *)(&S.a) = 0; // expected-warning {{cast from 'const int *'
>> >> to
>> >> 'int *' drops const qualifier}}
>> >> ^
>> >> Sema/warn-cast-qual.c:46:4: warning: cast discards ‘const’ qualifier
>> >> from pointer target type [-Wcast-qual]
>> >> *(int *)(&S.b) = 0; // expected-warning {{cast from 'const int *'
>> >> to
>> >> 'int *' drops const qualifier}}
>> >> ^
>> >> Sema/warn-cast-qual.c: In function ‘bar_1’:
>> >> Sema/warn-cast-qual.c:58:4: warning: cast discards ‘const’ qualifier
>> >> from pointer target type [-Wcast-qual]
>> >> *(int *)(&S.a) = 0; // expected-warning {{cast from 'const int *'
>> >> to
>> >> 'int *' drops const qualifier}}
>> >> ^
>> >>
>> >> One thing to note:
>> >>
>> >> Sema/warn-cast-qual.c:23:31: warning: to be safe all intermediate
>> >> pointers in cast from ‘int **’ to ‘volatile int **’ must be ‘const’
>> >> qualified [-Wcast-qual]
>> >> volatile int **intptrptrv = (volatile int **)intptrptr; //
>> >> expected-warning {{cast from 'int **' to 'volatile int **' must have
>> >> all
>> >> intermediate pointers const qualified}}
>> >> ^
>> >>
>> >> ^ both compilers talk about `const qualified`, even though the
>> >> `volatile`
>> >> is dropped.
>> >
>> >
>> > Fair enough - 'cv qualified' (or detecting which qualifier was being
>> > dropped) would probably be more technically correct. (detecting's
>> > probably
>> > better because 'cv qualifeid' might be confusing to the average user
>> > that's
>> > more likely to hit this over const than volatile)
>> >
>> >>
>> >> 2.2.
>> >>
>> >> $ gcc -x c++ -fsyntax-only -Wcast-qual -c Sema/warn-cast-qual.c
>> >> Sema/warn-cast-qual.c: In function ‘void foo()’:
>> >> Sema/warn-cast-qual.c:9:21: warning: cast from type ‘const char*
>> >> const’
>> >> to type ‘char*’ casts away qualifiers [-Wcast-qual]
>> >> char *y = (char *)ptr; // expected-warning {{cast from 'const char
>> >> *'
>> >> to 'char *' drops const qualifier}}
>> >> ^~~
>> >> Sema/warn-cast-qual.c:10:24: warning: cast from type ‘const char*
>> >> const*’ to type ‘char**’ casts away qualifiers [-Wcast-qual]
>> >> char **y1 = (char **)ptrptr; // expected-warning {{cast from
>> >> 'const
>> >> char *const' to 'char *' drops const qualifier}}
>> >> ^~~~~~
>> >> Sema/warn-cast-qual.c:11:36: warning: cast from type ‘const char*
>> >> const*’ to type ‘const char**’ casts away qualifiers [-Wcast-qual]
>> >> const char **y2 = (const char **)ptrptr; // expected-warning
>> >> {{cast
>> >> from 'const char *const *' to 'const char **' drops const qualifier}}
>> >> ^~~~~~
>> >> Sema/warn-cast-qual.c:14:36: warning: cast from type ‘const void*’ to
>> >> type ‘char*’ casts away qualifiers [-Wcast-qual]
>> >> char *z1 = (char *)(const void *)ptr; // expected-warning {{cast
>> >> from
>> >> 'const void *' to 'char *' drops const qualifier}}
>> >> ^~~
>> >> Sema/warn-cast-qual.c:17:24: warning: cast from type ‘volatile char*’
>> >> to
>> >> type ‘char*’ casts away qualifiers [-Wcast-qual]
>> >> char *vol2 = (char *)vol; // expected-warning {{cast from
>> >> 'volatile
>> >> char *' to 'char *' drops volatile qualifier}}
>> >> ^~~
>> >> Sema/warn-cast-qual.c:19:25: warning: cast from type ‘const volatile
>> >> char*’ to type ‘char*’ casts away qualifiers [-Wcast-qual]
>> >> char *volc2 = (char *)volc; // expected-warning {{cast from 'const
>> >> volatile char *' to 'char *' drops const and volatile qualifiers}}
>> >> ^~~~
>> >> Sema/warn-cast-qual.c:22:42: warning: cast from type ‘int**’ to type
>> >> ‘const int**’ casts away qualifiers [-Wcast-qual]
>> >> const int **intptrptrc = (const int **)intptrptr; //
>> >> expected-warning
>> >> {{cast from 'int **' to 'const int **' must have all intermediate
>> >> pointers
>> >> const qualified}}
>> >> ^~~~~~~~~
>> >> Sema/warn-cast-qual.c:23:48: warning: cast from type ‘int**’ to type
>> >> ‘volatile int**’ casts away qualifiers [-Wcast-qual]
>> >> volatile int **intptrptrv = (volatile int **)intptrptr; //
>> >> expected-warning {{cast from 'int **' to 'volatile int **' must have
>> >> all
>> >> intermediate pointers const qualified}}
>> >> ^~~~~~~~~
>> >> Sema/warn-cast-qual.c:29:32: warning: cast from type ‘const char**’
>> >> to
>> >> type ‘char**’ casts away qualifiers [-Wcast-qual]
>> >> char **charptrptr = (char **)charptrptrc; // expected-warning
>> >> {{cast
>> >> from 'const char *' to 'char *' drops const qualifier}}
>> >> ^~~~~~~~~~~
>> >> Sema/warn-cast-qual.c:32:27: warning: cast from type ‘const char*’ to
>> >> type ‘char*’ casts away qualifiers [-Wcast-qual]
>> >> char *charptr = (char *)constcharptr; // expected-warning {{cast
>> >> from
>> >> 'const char *' to 'char *' drops const qualifier}}
>> >> ^~~~~~~~~~~~
>> >> Sema/warn-cast-qual.c:33:39: warning: cast from type ‘const char*’ to
>> >> type ‘char*’ casts away qualifiers [-Wcast-qual]
>> >> const char *constcharptr2 = (char *)constcharptr; //
>> >> expected-warning
>> >> {{cast from 'const char *' to 'char *' drops const qualifier}}
>> >> ^~~~~~~~~~~~
>> >> Sema/warn-cast-qual.c: In function ‘void bar_0()’:
>> >> Sema/warn-cast-qual.c:45:16: warning: cast from type ‘const int*’ to
>> >> type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> *(int *)(&S.a) = 0; // expected-warning {{cast from 'const int *'
>> >> to
>> >> 'int *' drops const qualifier}}
>> >> ^
>> >> Sema/warn-cast-qual.c:46:16: warning: cast from type ‘const int*’ to
>> >> type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> *(int *)(&S.b) = 0; // expected-warning {{cast from 'const int *'
>> >> to
>> >> 'int *' drops const qualifier}}
>> >> ^
>> >> Sema/warn-cast-qual.c: In function ‘void bar_1()’:
>> >> Sema/warn-cast-qual.c:58:16: warning: cast from type ‘const int*’ to
>> >> type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> *(int *)(&S.a) = 0; // expected-warning {{cast from 'const int *'
>> >> to
>> >> 'int *' drops const qualifier}}
>> >> ^
>> >>
>> >> 2.3.
>> >> And here are the C++ reference warnings. As you can see, gcc warnings
>> >> are
>> >> rather broken i'd say...
>> >
>> >
>> > There's a lot to read through - what sort of brokenness were you
>> > referring
>> > to?
>>
>> > The fact that the error messages talk about pointers when the code is
>> > about references? Fair.
>> Yes, only that
>>
>> > Anything else?
>> Not as far as i can tell.
>> One thing to note is that for complicated, multi-pointer variables like:
>>
>> >> SemaCXX/warn-cast-qual.cpp: In function ‘void bar_0()’:
>> >> SemaCXX/warn-cast-qual.cpp:67:38: warning: cast from type ‘const
>> >> int**’
>> >> to type ‘int**’ casts away qualifiers [-Wcast-qual]
>> >> int **a0 = (int **)((const int **)a); // expected-warning {{cast
>> >> from
>> >> 'const int *' to 'int *' drops const qualifier}}
>> >> ^
>> the gcc outputs full types, and clang dissects them, and outputs only
>> invalid part.
>> But i'm pretty sure this isn't new.
>>
>> >>
>> >>
>> >> $ gcc -x c++ -fsyntax-only -Wcast-qual -c SemaCXX/warn-cast-qual.cpp
>> >> SemaCXX/warn-cast-qual.cpp: In function ‘void foo_0()’:
>> >> SemaCXX/warn-cast-qual.cpp:24:20: warning: cast from type ‘const
>> >> int*’
>> >> to type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> int &a2 = (int &)a; // expected-warning
>> >> {{cast
>> >> from 'const int' to 'int &' drops const qualifier}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:25:26: warning: cast from type ‘const
>> >> int*’
>> >> to type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> const int &a3 = (int &)a; // expected-warning
>> >> {{cast
>> >> from 'const int' to 'int &' drops const qualifier}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:26:35: warning: cast from type ‘const
>> >> int*’
>> >> to type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> int &a4 = (int &)((const int &)a); // expected-warning
>> >> {{cast
>> >> from 'const int' to 'int &' drops const qualifier}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:27:28: warning: cast from type ‘const
>> >> int*’
>> >> to type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> int &a5 = (int &)((int &)a); // expected-warning
>> >> {{cast
>> >> from 'const int' to 'int &' drops const qualifier}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:28:34: warning: cast from type ‘const
>> >> int*’
>> >> to type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> const int &a6 = (int &)((int &)a); // expected-warning
>> >> {{cast
>> >> from 'const int' to 'int &' drops const qualifier}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:29:41: warning: cast from type ‘const
>> >> int*’
>> >> to type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> const int &a7 = (int &)((const int &)a); // expected-warning
>> >> {{cast
>> >> from 'const int' to 'int &' drops const qualifier}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:30:40: warning: cast from type ‘const
>> >> int*’
>> >> to type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> const int &a8 = (const int &)((int &)a); // expected-warning
>> >> {{cast
>> >> from 'const int' to 'int &' drops const qualifier}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp: In function ‘void foo_1()’:
>> >> SemaCXX/warn-cast-qual.cpp:39:20: warning: cast from type ‘volatile
>> >> int*’ to type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> int &a2 = (int &)a; // expected-warning
>> >> {{cast from 'volatile int' to 'int &' drops volatile qualifier}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:40:29: warning: cast from type ‘volatile
>> >> int*’ to type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> volatile int &a3 = (int &)a; // expected-warning
>> >> {{cast from 'volatile int' to 'int &' drops volatile qualifier}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:41:38: warning: cast from type ‘volatile
>> >> int*’ to type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> int &a4 = (int &)((volatile int &)a); // expected-warning
>> >> {{cast from 'volatile int' to 'int &' drops volatile qualifier}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:42:28: warning: cast from type ‘volatile
>> >> int*’ to type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> int &a5 = (int &)((int &)a); // expected-warning
>> >> {{cast from 'volatile int' to 'int &' drops volatile qualifier}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:43:37: warning: cast from type ‘volatile
>> >> int*’ to type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> volatile int &a6 = (int &)((int &)a); // expected-warning
>> >> {{cast from 'volatile int' to 'int &' drops volatile qualifier}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:44:47: warning: cast from type ‘volatile
>> >> int*’ to type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> volatile int &a7 = (int &)((volatile int &)a); // expected-warning
>> >> {{cast from 'volatile int' to 'int &' drops volatile qualifier}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:45:46: warning: cast from type ‘volatile
>> >> int*’ to type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> volatile int &a8 = (volatile int &)((int &)a); // expected-warning
>> >> {{cast from 'volatile int' to 'int &' drops volatile qualifier}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp: In function ‘void foo_2()’:
>> >> SemaCXX/warn-cast-qual.cpp:54:20: warning: cast from type ‘const
>> >> volatile int*’ to type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> int &a2 = (int &)a; //
>> >> expected-warning {{cast from 'const volatile int' to 'int &' drops
>> >> const and
>> >> volatile qualifiers}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:55:35: warning: cast from type ‘const
>> >> volatile int*’ to type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> const volatile int &a3 = (int &)a; //
>> >> expected-warning {{cast from 'const volatile int' to 'int &' drops
>> >> const and
>> >> volatile qualifiers}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:56:44: warning: cast from type ‘const
>> >> volatile int*’ to type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> int &a4 = (int &)((const volatile int &)a); //
>> >> expected-warning {{cast from 'const volatile int' to 'int &' drops
>> >> const and
>> >> volatile qualifiers}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:57:28: warning: cast from type ‘const
>> >> volatile int*’ to type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> int &a5 = (int &)((int &)a); //
>> >> expected-warning {{cast from 'const volatile int' to 'int &' drops
>> >> const and
>> >> volatile qualifiers}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:58:43: warning: cast from type ‘const
>> >> volatile int*’ to type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> const volatile int &a6 = (int &)((int &)a); //
>> >> expected-warning {{cast from 'const volatile int' to 'int &' drops
>> >> const and
>> >> volatile qualifiers}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:59:59: warning: cast from type ‘const
>> >> volatile int*’ to type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> const volatile int &a7 = (int &)((const volatile int &)a); //
>> >> expected-warning {{cast from 'const volatile int' to 'int &' drops
>> >> const and
>> >> volatile qualifiers}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:60:58: warning: cast from type ‘const
>> >> volatile int*’ to type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> const volatile int &a8 = (const volatile int &)((int &)a); //
>> >> expected-warning {{cast from 'const volatile int' to 'int &' drops
>> >> const and
>> >> volatile qualifiers}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp: In function ‘void bar_0()’:
>> >> SemaCXX/warn-cast-qual.cpp:67:38: warning: cast from type ‘const
>> >> int**’
>> >> to type ‘int**’ casts away qualifiers [-Wcast-qual]
>> >> int **a0 = (int **)((const int **)a); // expected-warning {{cast
>> >> from
>> >> 'const int *' to 'int *' drops const qualifier}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:68:31: warning: cast from type ‘const
>> >> int**’
>> >> to type ‘int**’ casts away qualifiers [-Wcast-qual]
>> >> int **a1 = (int **)((int **)a); // expected-warning {{cast
>> >> from
>> >> 'const int *' to 'int *' drops const qualifier}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:73:43: warning: cast from type ‘const
>> >> int**’
>> >> to type ‘int**’ casts away qualifiers [-Wcast-qual]
>> >> const int **a4 = (const int **)((int **)a); //
>> >> expected-warning {{cast from 'const int *' to 'int *' drops const
>> >> qualifier}} expected-warning {{cast from 'int **' to 'const int **'
>> >> must
>> >> have all intermediate pointers const qualified to be safe}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:73:44: warning: cast from type ‘int**’ to
>> >> type ‘const int**’ casts away qualifiers [-Wcast-qual]
>> >> const int **a4 = (const int **)((int **)a); //
>> >> expected-warning {{cast from 'const int *' to 'int *' drops const
>> >> qualifier}} expected-warning {{cast from 'int **' to 'const int **'
>> >> must
>> >> have all intermediate pointers const qualified to be safe}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp: In function ‘void bar_1()’:
>> >> SemaCXX/warn-cast-qual.cpp:81:38: warning: cast from type ‘const
>> >> int**’
>> >> to type ‘int**’ casts away qualifiers [-Wcast-qual]
>> >> int *&a0 = (int *&)((const int *&)a); // expected-warning {{cast
>> >> from
>> >> 'const int *' to 'int *' drops const qualifier}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:82:31: warning: cast from type ‘const
>> >> int**’
>> >> to type ‘int**’ casts away qualifiers [-Wcast-qual]
>> >> int *&a1 = (int *&)((int *&)a); // expected-warning {{cast
>> >> from
>> >> 'const int *' to 'int *' drops const qualifier}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:87:43: warning: cast from type ‘const
>> >> int**’
>> >> to type ‘int**’ casts away qualifiers [-Wcast-qual]
>> >> const int *&a4 = (const int *&)((int *&)a); //
>> >> expected-warning {{cast from 'const int *' to 'int *' drops const
>> >> qualifier}} expected-warning {{cast from 'int *' to 'const int *&' must
>> >> have
>> >> all intermediate pointers const qualified to be safe}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:87:44: warning: cast from type ‘int**’ to
>> >> type ‘const int**’ casts away qualifiers [-Wcast-qual]
>> >> const int *&a4 = (const int *&)((int *&)a); //
>> >> expected-warning {{cast from 'const int *' to 'int *' drops const
>> >> qualifier}} expected-warning {{cast from 'int *' to 'const int *&' must
>> >> have
>> >> all intermediate pointers const qualified to be safe}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp: In function ‘void baz_0()’:
>> >> SemaCXX/warn-cast-qual.cpp:100:9: warning: cast from type ‘const
>> >> baz_0()::C*’ to type ‘baz_0()::C*’ casts away qualifiers [-Wcast-qual]
>> >> ((C &)S).B(); // expected-warning {{cast from 'const C' to 'C &'
>> >> drops const qualifier}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:101:9: warning: cast from type ‘const
>> >> baz_0()::C*’ to type ‘baz_0()::C*’ casts away qualifiers [-Wcast-qual]
>> >> ((C &)S).A(); // expected-warning {{cast from 'const C' to 'C &'
>> >> drops const qualifier}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:103:10: warning: cast from type ‘const
>> >> baz_0()::C*’ to type ‘baz_0()::C*’ casts away qualifiers [-Wcast-qual]
>> >> ((C *)&S)->B(); // expected-warning {{cast from 'const C *' to 'C
>> >> *'
>> >> drops const qualifier}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:104:10: warning: cast from type ‘const
>> >> baz_0()::C*’ to type ‘baz_0()::C*’ casts away qualifiers [-Wcast-qual]
>> >> ((C *)&S)->A(); // expected-warning {{cast from 'const C *' to 'C
>> >> *'
>> >> drops const qualifier}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp: In function ‘void baz_1()’:
>> >> SemaCXX/warn-cast-qual.cpp:119:16: warning: cast from type ‘const
>> >> int*’
>> >> to type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> (int &)(S.a) = 0; // expected-warning {{cast from 'const int' to
>> >> 'int &' drops const qualifier}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:122:18: warning: cast from type ‘const
>> >> int*’
>> >> to type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> *(int *)(&S.a) = 0; // expected-warning {{cast from 'const int
>> >> *'
>> >> to 'int *' drops const qualifier}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:128:16: warning: cast from type ‘const
>> >> int*’
>> >> to type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> (int &)(S.a) = 0; // expected-warning {{cast from 'const int' to
>> >> 'int &' drops const qualifier}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:129:16: warning: cast from type ‘const
>> >> int*’
>> >> to type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> (int &)(S.b) = 0; // expected-warning {{cast from 'const int' to
>> >> 'int &' drops const qualifier}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:131:18: warning: cast from type ‘const
>> >> int*’
>> >> to type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> *(int *)(&S.a) = 0; // expected-warning {{cast from 'const int
>> >> *'
>> >> to 'int *' drops const qualifier}}
>> >> ^
>> >> SemaCXX/warn-cast-qual.cpp:132:18: warning: cast from type ‘const
>> >> int*’
>> >> to type ‘int*’ casts away qualifiers [-Wcast-qual]
>> >> *(int *)(&S.b) = 0; // expected-warning {{cast from 'const int
>> >> *'
>> >> to 'int *' drops const qualifier}}
>> >> ^
>> >>
>> >> So to me it seems that for our clang's testcases, both compilers
>> >> produce
>> >> the compatible set of warnings...
>> >>
>> >>
>> >> Repository:
>> >> rL LLVM
>> >>
>> >> https://reviews.llvm.org/D33102
>> >>
>> >>
>> >>
>> >
>>
>> Roman.
More information about the cfe-commits
mailing list