[cpp] Support for all the enums

[chandangreddy]

Currently, only isl::stat is supported. We can follow the same strategy as isl::stat and all enums to isl.h.top and generate appropriate static_casts while generating methods. We need to decide on names of enums as the simple rule of removing type name from enums will result in C++ default keywords for some like isl_ast_node_for, isl_ast_node_if etc..

[tobiasgrosser]

Yes, would be great to support these. I assume that Sven would prefer to auto-generate the enums. We have already a translation table for cases where names conflict with C++ keywords. We can likely reuse this here.

[tobiasgrosser]

@chandangreddy : Any plans to move this forward. I think it would be great to see some of the isl ast interface to be exposed.

[chandangreddy]

@TobiG Yes, I have modified the generator to handle all enums uniformly. It basically strips isl_ from the name of enums and does static_cast whenever necessary. But I assume that all the enum classes are defined manually in the isl.h.top. I think, it not worth the effort to generate enum definitions automatically, given the limited number of enums that we have. Could you please share the translation tables that is agreed upon?
I can send PR for handling enums with their definitions in isl.h.top.

[tobiasgrosser]

@chandangreddy : Thanks for looking into this. I am slightly confused what you mean. You say you modified the generator, but prefer to add manual declarations of enums to isl.h.top? This seems to be inconsistent?

I personally believe for small enums which are unlikely to ever be extended we can indeed just copy the declaration to isl.h.top. isl_dim is such a case. Maybe we should start with this and a couple of related functions?

Larger enums (such as the ones in the AST generator) are likely better auto-generated.

The translation table is part of interface/cpp.cc:

/* An array listing functions that must be renamed and the function name they    
 * should be renamed to. We currently rename functions in case their name would  
 * match a reserved C++ keyword, which is not allowed in C++.                    
 */                                                                              
static const char *rename_map[][2] = {                                           
        { "union", "unite" },                                                    
};   

and is still mostly empty.

[chandangreddy]

@TobiG The generator modifications are to generate static_casts in the methods like

enum isl::ast_op_type ast_expr::get_op_type() const {
  auto res = isl_ast_expr_get_op_type(get());
  return static_cast<enum isl::ast_op_type>(res);
}

isl::multi_pw_aff multi_pw_aff::add_dims(enum isl::dim_type type, unsigned int n) const {
  auto res = isl_multi_pw_aff_add_dims(copy(), static_cast<enum isl_dim_type>(type), n);
  return manage(res);
}

The enum declarations are manually added to isl.h.top.
My question was did you guys had discussion regarding translation for other C++ keywords like for, id, and, or etc...?

[tobiasgrosser]

Thanks, now i understand your use of the generator.

No, I don't think we had a discussion here. You may have a look at these two patches:

simbuerg/isl@1a95bcc
simbuerg/isl@4be4dd0
simbuerg/isl@a052050

for how enums in general can be added to the generator.

However, to spark the discussion a minimal patch with the enum in isl.h.top and the small code generator changes might be a good start.