[PATCH] libgccjit: add some reflection functions in the jit C api [WIP]

[Antoni Boucher]

By the way, that seemed off to return NULL for the function returning a 
size_t to indicate an error. So I changed it to return -1 (and return 
type to ssize_t).  Is that the proper way to indicate an error?

I also wanted to mention that this patch is still a work-in-progress as 
I'm adding a few other functions.

On Fri, Oct 02, 2020 at 04:24:26PM -0400, David Malcolm wrote:
>On Fri, 2020-10-02 at 16:17 -0400, David Malcolm wrote:
>> On Tue, 2020-09-01 at 21:01 -0400, Antoni Boucher via Jit wrote:
>> > Hello.
>> > This WIP patch implements new reflection functions in the C API as
>> > mentioned in bug 96889.
>> > I'm looking forward for feedbacks on this patch.
>> > It's WIP because I'll probably add a few more reflection functions.
>> > Thanks.
>>
>> Sorry about the belated review, looks like I missed this one.
>>
>> At a high level, it seems reasonable.
>>
>> Do you have a copyright assignment in place for GCC contributions?
>> See https://gcc.gnu.org/contribute.html
>>
>> [...]
>
>diff --git a/gcc/jit/docs/topics/compatibility.rst
>> > b/gcc/jit/docs/topics/compatibility.rst
>> > index bb3387fa583..7e786194ded 100644
>> > --- a/gcc/jit/docs/topics/compatibility.rst
>> > +++ b/gcc/jit/docs/topics/compatibility.rst
>> > @@ -219,3 +219,14 @@ entrypoints:
>> >    * :func:`gcc_jit_version_minor`
>> >
>> >    * :func:`gcc_jit_version_patchlevel`
>> > +
>> > +.. _LIBGCCJIT_ABI_14:
>> > +
>> > +``LIBGCCJIT_ABI_14``
>> > +--------------------
>> > +``LIBGCCJIT_ABI_14`` covers the addition of reflection functions
>> > via API
>> > +entrypoints:
>> > +
>> > +  * :func:`gcc_jit_function_get_return_type`
>> > +
>> > +  * :func:`gcc_jit_function_get_param_count`
>>
>> This will now need bumping to 15; 14 covers the addition of
>> gcc_jit_global_set_initializer.
>>
>> [...]
>>
>> > +/* Public entrypoint.  See description in libgccjit.h.
>> > +
>> > +   After error-checking, the real work is done by the
>> > +   gcc::jit::recording::function::get_return_type method, in
>> > +   jit-recording.h.  */
>> > +
>> > +gcc_jit_type *
>> > +gcc_jit_function_get_return_type (gcc_jit_function *func)
>> > +{
>>
>> This one is missing a:
>>   RETURN_NULL_IF_FAIL (func, NULL, NULL, "NULL function");
>>
>>
>> > +    return (gcc_jit_type *)func->get_return_type ();
>> > +}
>>
>> [...]
>>
>> > diff --git a/gcc/jit/libgccjit.h b/gcc/jit/libgccjit.h
>> > index 1c5a12e9c01..6999ce25ca2 100644
>> > --- a/gcc/jit/libgccjit.h
>> > +++ b/gcc/jit/libgccjit.h
>>
>> [...]
>>
>> > @@ -1503,6 +1511,22 @@ gcc_jit_version_minor (void);
>> >  extern int
>> >  gcc_jit_version_patchlevel (void);
>> >
>> > +#define LIBGCCJIT_HAVE_gcc_jit_function_reflection
>> > +
>> > +/* Reflection functions to get the number of parameters and return
>> > types of
>> > +   a function from the C API.
>>
>> "return type", is better grammar, I think, given that "function" is
>> singular.
>>
>> > +
>> > +   "vec_type" should be a vector type, created using
>> > gcc_jit_type_get_vector.
>>
>> This line about "vec_type" seems to be a leftover from a copy&paste.
>>
>>
>> > +   This API entrypoint was added in LIBGCCJIT_ABI_14; you can test
>> > for its
>> > +   presence using
>> > +     #ifdef LIBGCCJIT_HAVE_gcc_jit_function_reflection
>>
>> Version number will need bumping, as mentioned above.
>>
>> [...]
>>
>> > diff --git a/gcc/jit/libgccjit.map b/gcc/jit/libgccjit.map
>> > index 6137dd4b4b0..b28f81a7a32 100644
>> > --- a/gcc/jit/libgccjit.map
>> > +++ b/gcc/jit/libgccjit.map
>> > @@ -186,4 +186,10 @@ LIBGCCJIT_ABI_13 {
>> >      gcc_jit_version_major;
>> >      gcc_jit_version_minor;
>> >      gcc_jit_version_patchlevel;
>> > -} LIBGCCJIT_ABI_12;
>> > \ No newline at end of file
>> > +} LIBGCCJIT_ABI_12;
>> > +
>> > +LIBGCCJIT_ABI_14 {
>> > +  global:
>> > +    gcc_jit_function_get_return_type;
>> > +    gcc_jit_function_get_param_count;
>> > +} LIBGCCJIT_ABI_13;
>>
>> Likewise.
>>
>> [...]
>>
>> Otherwise looks good to me.
>>
>> Bonus points for adding C++ bindings (and docs for them), but I don't
>> know of anyone using the C++ bindings.
>
>
>Also, please add "PR jit/96889" to the ChangeLog entries, and [PR96889]
>to the subject line.
>
>Dave
>