[PATCH] D33102: [clang] Implement -Wcast-qual for C++
Roman Lebedev via cfe-commits
cfe-commits at lists.llvm.org
Tue Jun 6 13:56:59 PDT 2017
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.
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