On Sun, Apr 27, 2014 at 12:50 PM, Prathamesh Kulkarni <bilbotheelffri...@gmail.com> wrote: > On Sun, Apr 27, 2014 at 11:22 PM, <pins...@gmail.com> wrote: >> >> >>> On Apr 27, 2014, at 10:09 AM, Prathamesh Kulkarni >>> <bilbotheelffri...@gmail.com> wrote: >>> >>>> On Sun, Apr 27, 2014 at 8:48 PM, Trevor Saunders <tsaund...@mozilla.com> >>>> wrote: >>>>> On Sun, Apr 27, 2014 at 06:21:20PM +0530, Prathamesh Kulkarni wrote: >>>>>> On Sun, Apr 27, 2014 at 5:31 PM, Trevor Saunders <tsaund...@mozilla.com> >>>>>> wrote: >>>>>>> On Sun, Apr 27, 2014 at 02:31:46AM +0530, Prathamesh Kulkarni wrote: >>>>>>> Hi, >>>>>>> Shall it a good idea to add new warning -Wsizeof-array-argument that >>>>>>> warns when sizeof is applied on parameter declared as an array ? >>>>>> >>>>>> Seems reasonable enough. >>>>>> >>>>>>> Similar to clang's -Wsizeof-array-argument: >>>>>>> http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20110613/042812.html >>>>>>> This was also reported as PR6940: >>>>>>> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=6940 >>>>>>> >>>>>>> I have attached a patch that adds the warning to C front-end. >>>>>> >>>>>> if we're doing this for C, we should probably do it for C++ too. >>>>>> >>>>>>> I implemented it by adding a new member BOOL_BITFIELD is_array_parm to >>>>>>> tree_parm_decl. Not sure if that's a good approach. >>>>>> >>>>>> I'm about the last one who should comment on this, but it seems pretty >>>>>> crazy you can't use data that's already stored. >>>>> AFAIU, the information about declarator is stored in c_declarator. >>>>> c_declarator->kind == cdk_array holds true >>>>> if the declarator is an array. However in push_parm_decl, call to >>>>> grokdeclarator returns decl of pointer_type, corresponding to array >>>>> declarator if the array is parameter (TREE_TYPE (decl) is >>>>> pointer_type). So I guess we lose that information there. >>>> >>>> I guess that sort of makes sense, so I'll shut up ;) >>>> >>>>>>> Index: gcc/tree-core.h >>>>>>> =================================================================== >>>>>>> --- gcc/tree-core.h (revision 209800) >>>>>>> +++ gcc/tree-core.h (working copy) >>>>>>> @@ -1411,6 +1411,7 @@ struct GTY(()) tree_const_decl { >>>>>>> struct GTY(()) tree_parm_decl { >>>>>>> struct tree_decl_with_rtl common; >>>>>>> rtx incoming_rtl; >>>>>>> + BOOL_BITFIELD is_array_parm; >>>>>> >>>>>> BOOL_BITFIELD only makes sense if you declare it as an actually bitfield >>>>>> with size less than that of unisgned int, otherwise you might as well >>>>>> use that directly. On the other hand I wonder if we can't just nuke >>>>>> BOOL_BITFIELD, it seems to be legacy from a time of C and bool not being >>>>>> a builtin type? >>>>> Thanks, I wasn't aware of that. Could we now use C++ bool type instead ? >>>> >>>> you can certainly do |bool x;| as struct fields, that's already all >>>> over. However its not entirely clear to me if |bool x : 1;| will work >>>> everywhere and take the single bit you'd expect, istr there being >>>> compilers that do stupid things if you use multiple types next to each >>>> other in bitfields, but I'm not sure if we need to care about any of >>>> those. >>> Changed to bool is_array_parm; >>> and from macros to inline functions. >> >> I don't like this field being part of the generic code as it increases the >> size of the struct for all front-ends and even during LTO. Is there a way to >> do this using one of the language specific bitfields that are already there >> (language flags iirc)? > I guess the warning would be shared by c-family languages, so I had > added the field to tree_parm_decl. > This patch is C-only (added the member to c-lang.h:lang_type instead).
That was not talking about. I was talking about DECL_LANG_FLAG_* which is already there for your usage. You should be able to use DECL_LANG_FLAG_2 as it is unused for both C and C++ for PARM_DECLs. This should also reduce the size of the patch too. Thanks, Andrew Pinski > > [gcc/c] > * c-decl.c (push_parm_decl): Check if declarator is array parameter. > * c-lang.h (lang_type): Add new member is_array_parm. > * c-typeck.c (c_expr_sizeof_expr): Check for sizeof-array-argument warning. > > [gcc/c-family] > * c.opt (-Wsizeof-array-argument): New option. > > [gcc/testsuite/gcc.dg] > * sizeof-array-argument.c: New test-case. > > Thanks and Regards, > Prathamesh >> >> Thanks, >> Andrew >> >> >>> >>> [gcc] >>> * tree-core.h (tree_parm_decl): Add new member bool is_array_parm >>> * tree.h (set_parm_decl_is_array): New function. >>> (parm_decl_array_p): New function. >>> >>> [gcc/c] >>> * c-decl.c (push_parm_decl): Call set_parm_decl_is_array. >>> * c-typeck.c (c_expr_sizeof_expr): Add check for sizeof-array-argument >>> warning. >>> >>> [gcc/c-family] >>> * c.opt (-Wsizeof-array-argument): New option. >>> >>> [gcc/testsuite/gcc.dg] >>> * sizeof-array-argument.c: New test-case. >>> >>> Thanks and Regards, >>> Prathamesh >>>> >>>> Trev >>>> >>>>>> >>>>>>> Index: gcc/tree.h >>>>>>> =================================================================== >>>>>>> --- gcc/tree.h (revision 209800) >>>>>>> +++ gcc/tree.h (working copy) >>>>>>> @@ -1742,6 +1742,7 @@ extern void protected_set_expr_location >>>>>>> #define TYPE_LANG_SPECIFIC(NODE) \ >>>>>>> (TYPE_CHECK (NODE)->type_with_lang_specific.lang_specific) >>>>>>> >>>>>>> + >>>>>>> #define TYPE_VALUES(NODE) (ENUMERAL_TYPE_CHECK >>>>>>> (NODE)->type_non_common.values) >>>>>>> #define TYPE_DOMAIN(NODE) (ARRAY_TYPE_CHECK >>>>>>> (NODE)->type_non_common.values) >>>>>>> #define TYPE_FIELDS(NODE) \ >>>>>>> @@ -2258,6 +2259,12 @@ extern void decl_value_expr_insert (tree >>>>>>> #define DECL_INCOMING_RTL(NODE) \ >>>>>>> (PARM_DECL_CHECK (NODE)->parm_decl.incoming_rtl) >>>>>>> >>>>>>> +#define SET_PARM_DECL_IS_ARRAY(NODE, val) \ >>>>>>> + (PARM_DECL_CHECK (NODE)->parm_decl.is_array_parm = (val)) >>>>>> >>>>>> if we're adding more stuff here is there a reason it needs to be a macro >>>>>> not a inline function? >>>>> No, shall change that to inline function. >>>>>> >>>>>> Trev >>> <sizeof-array-argument.patch>
