[cfe-dev] extending C with Clang (bug in buildsystem?)

[Mattias Holm]

Speaking about attributes, it seems that if I change Attr.td, then 
AttrImpl.inc and Attrs.inc are not regenerated (I am using Makefiles 
generated by CMake).

I assume this is a bug, at the moment I have type make clean before 
rebuilding clang everytime I change the Attr.td file.

/ Mattias


On 2010-09-03 08:19, John McCall wrote:
>
> On Sep 2, 2010, at 11:08 PM, Abramo Bagnara wrote:
>
>> Il 03/09/2010 00:12, John McCall ha scritto:
>>>
>>> On Sep 2, 2010, at 3:01 PM, Wei Li wrote:
>>>
>>>> Dear All:
>>>>
>>>> I am  extending C language for my research work and using Clang for
>>>> this. I am adding some annotations which are not part of C language
>>>> but will be helpful for my specific work.
>>>>
>>>> Now consider the following:
>>>>
>>>> int  foo() { return 1; }
>>>>
>>>> is a legal  expression in C and is acceptable by the Clang. Now if I
>>>> introduce a new annotation say "Wei"  and write the above expression
>>>> as
>>>>
>>>> int foo() Wei { return 1;}
>>>>
>>>> I have to make changes in Clang at the front end to make it work. I
>>>> see my extension as super set of C. That is my work should accept the
>>>> legal C program as well.
>>>>
>>>> Now here is the problem. When I make changes in the Clang . It accepts
>>>> the new annotation but breaks the C programs. My understanding is that
>>>> as I am adding to C so if my stuff works, any legal C  program should
>>>> also work. But its not happening. I am not a compiler person. I am an
>>>> engineer. Any suggestions? why clang is doing this or am I doing
>>>> something    which is not compatible with the C grammar.?
>>>
>>> Your parser modifications are probably broken.  I would strongly
>>> suggest implementing Wei as a macro for __attribute__((Wei)) and then
>>> just adding support for your new attribute.
>>
>> Isn't a better idea for user that need this to have only one
>>
>> __attribute__((custom(Expr)))
>>
>> and store the Expr in the AST?
>
> Why would this be better for users?  Easier to implement new annotations,
> maybe, but easier for users?
>
> Sean Hunt has done a lot of work to make it easy to add new attributes,
> and more is forthcoming;  I would much prefer that over making a private
> language of annotations expressed cumbersomely with expressions.
>
> John.