[LLVMdev] PATCH: AddressSanitizer: Fix errors about mis-matched exception specifiers for intercepted libc functions on Linux

[Chandler Carruth]

On Mon, Jun 25, 2012 at 2:25 AM, Kostya Serebryany <kcc at google.com> wrote:

>
>
> On Mon, Jun 25, 2012 at 1:10 PM, Chandler Carruth <chandlerc at google.com>wrote:
>
>> Hello,
>>
>> On modern Linux installs, glibc has a very annoying practice: it adds an
>> empty exception specifier to lots of libc functions as an optimization. It
>> only does this if the compiler is modern and GCC-like, and we are compiling
>> in C++ mode.
>>
>> This, however, causes GCC to complain about signature mismatches between
>> the glibc functions declared in malloc.h and those defined as an alias in
>> the interceptors library:
>>
>> ..../asan_malloc_linux.cc:57:1: error: declaration of 'void free(void*)'
>> has a different exception specifier
>> /usr/include/malloc.h:66:13: error: from previous declaration 'void
>> free(void*) throw ()'
>>
>>
>> I've attached a complete hack of a patch to address this... but surely
>> there is a better way? I'm open to suggestions about this sticky issue.
>>
>
> ouch!
> How do I reproduce the failure?
> For me, the code build fine with gcc (4.4.3 and 4.7.0).
>

I'm not sure... maybe add '-pedantic' to your compile flags? It triggers
easily with the in-progress CMake build, and one of the differences is
inheritting the fairly strict set of compile flags from LLVM proper.


>
>
> --kcc
>
>
>>
>> Amusingly, this is only diagnosed by GCC, not by Clang. =] So I didn't
>> even notice it at first.
>> -Chandler
>>
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>>
>>
>
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