[cfe-dev] CanQualType for ssize_t

[Alex L via cfe-dev]

The C11 standard has the following paragraph for 'z':

Specifies that a following d, i, o, u, x, or X conversion specifier applies
to a size_t or the corresponding signed integer type argument; or that a
following n conversion specifier applies to a pointer to a signed integer
type corresponding to size_t argument.

If I interpret it correctly (please correct me if I'm wrong) then this
means that for '%zd' you can use a type that identical to the target's
SizeType, except that it has to be signed.

Alex

On 12 July 2017 at 03:01, Александр Шапошников <
alexander.v.shaposhnikov at gmail.com> wrote:

>
>
> On Tue, Jul 11, 2017 at 5:19 PM, Alexander Shaposhnikov <
> shal1t712 at gmail.com> wrote:
>
>> Hi,
>> I have a question regarding the right way to get CanQualType/QualType for
>> "ssize_t".
>>
>> The class ASTContext
>> <https://clang.llvm.org/doxygen/classclang_1_1ASTContext.html#a7c89acd533ffea38c5011885d8d029e4>
>>  (https://clang.llvm.org/doxygen/ASTContext_8cpp_source.html#l04524)
>> has a number of methods: getIntMaxType, getUintMaxType, getSizeType etc
>> but if i am not mistaken it doesn't have the counterpart for "ssize_t".
>> After looking at the implementation of those methods i see that it's
>> missing in the class TargetInfo
>> <https://clang.llvm.org/doxygen/classclang_1_1TargetInfo.html> either.
>> https://clang.llvm.org/doxygen/include_2clang_2Basic_2Target
>> Info_8h_source.html#l00228 .
>>
>> Some context:
>>
>> in PrintfSpecifier::getArgType (in ./lib/Analysis/PrintfFormatString.cpp)
>> there is a FIXME:
>>
>>      case LengthModifier::AsSizeT:
>>          return ArgType(); // FIXME: ssize_t
>>
>> as a result Clang doesn't analyze the format string "%zd" correctly
>> and doesn't warn on the following (broken) code:
>>
>>     int main() {
>>       printf("%zd", 12.2);
>>       return 0;
>>     }
>>
>> Kind regards,
>> Alexander Shaposhnikov
>>
>
>
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