[cfe-dev] -rewrite-objc, C and blocks

[jahanian]

Concept is right. However, rewriter project was done for a specific purpose and generates c++ code 
as the input might be objective-c++. It is best for you to use the rewrite-obj model and have you own
-rewrite-block which generates c code.

- Fariborz

On Oct 1, 2010, at 3:16 AM, Pierre Habouzit wrote:

> I intended to use clang -rewrite-objc to be able to compile code using
> blocks on targets unsupported by clang. I'm totally uninterested in the
> ObjC rewriting, only the blocks one.
> 
> Sadly, this rewriting module rewrites to C++ even when the source code
> in question is just plain old C.
> 
> I'm under the impression, that when the source code is C, only the fact
> that clang is generating structs with constructors and RAII use of the
> defined blocks. For example:
> 
>    struct __main_block_impl_0 {
>      struct __block_impl impl;
>      struct __main_block_desc_0* Desc;
>      int a;
>      __main_block_impl_0(void *fp, struct __main_block_desc_0 *desc, int _a, int flags=0) : a(_a) {
>        impl.isa = &_NSConcreteStackBlock;
>        impl.Flags = flags;
>        impl.FuncPtr = fp;
>        Desc = desc;
>      }
>    };
> 
>    [...]
> 
>    int main(void) {
>        int a = 1;
>        struct __Block_byref_c_0 c = {(void*)0,(struct __Block_byref_c_0 *)&c, 0, sizeof(struct __Block_byref_c_0), 1};
> 
>        int (*f)(int) = (int (*)(int))&__main_block_impl_0((void *)__main_block_func_0, &__main_block_desc_0_DATA, a);
>        [...]
>    }
> 
> I'm under the impression that the following "rewrite" would be correct:
> 
>    struct __main_block_impl_0 {
>      struct __block_impl impl;
>      struct __main_block_desc_0* Desc;
>      int a;
>    #ifdef __cplusplus
>      __main_block_impl_0(void *fp, struct __main_block_desc_0 *desc, int _a, int flags=0) : a(_a) {
>        impl.isa = &_NSConcreteStackBlock;
>        impl.Flags = flags;
>        impl.FuncPtr = fp;
>        Desc = desc;
>      }
>    #endif
>    };
>    #ifndef __cplusplus
>    #define __main_block_impl_0(fp, desc, _a, flags) \
>        ((struct __main_block_impl_0){               \
>            .impl = {                                \
>                .isa = &_NSConcreteStackBlock,       \
>                .Flags = flags,                      \
>                .FuncPtr = fp,                       \
>            },                                       \
>            .Desc = desc,                            \
>            .a = (_a),                               \
>        })
>    #endif
> 
>    [...]
> 
>    int main(void) {
>        int a = 1;
>        struct __Block_byref_c_0 c = {(void*)0,(struct __Block_byref_c_0 *)&c, 0, sizeof(struct __Block_byref_c_0), 1};
> 
>        int (*f)(int) = (int (*)(int))&__main_block_impl_0((void *)__main_block_func_0, &__main_block_desc_0_DATA, a);
>        [...]
>    }
> 
> 
> Am I correct, or am I missing something obvious ?
> 
> 
> -- 
> ·O·  Pierre Habouzit
> ··O                                                madcoder at debian.org
> OOO                                                http://www.madism.org
> _______________________________________________
> cfe-dev mailing list
> cfe-dev at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev