Re: Help forging a function_decl

[Martin Jambor <mjambor at suse dot cz>]

Hi,

On Wed, Jul 17, 2013 at 04:52:30PM -0300, Rodolfo Guilherme Wottrich wrote:
> Hello there,
> 
> Please disregard this message in case it doesn't fit here.
> 
> During compilation of a C file, I need to be able to create a global
> function definition, with whatever a body I may have forged. I mean,
> the function is not going to be present in the source file and I got
> to create the respective tree structure so it can be later gimplified
> and further compiled like any other function present in the source. I
> would only need to create that function in case some OpenMP directive
> is encountered, so my latest and unsuccessful try to do so was to
> create the tree structures for a FUNCTION_DECL and, say, a variable
> declared inside the scope of that function, after the parsing of a
> #pragma omp parallel in c_parser_omp_parallel() in file c-parser.c. I
> followed and tried to re-create the steps I found in the function
> create_omp_child_function(), in file omp-low.c, and
> http://gcc.gnu.org/onlinedocs/gccint/Function-Basics.html#Function-Basics.
> 
> I think maybe the problem is that my new function doesn't go under
> rest_of_compilation, therefore it is not gimplified and obviously no
> code for it is generated.

it's a bit difficult to say without knowing what you are doing and at
what compilation stage you are doing it but perhaps you could try
calling cgraph_add_new_function on the new decl?  Also try reading the
comment at the beginning of cgraphunit.c.

Hope it helps,

Martin


> 
> Summarizing: I tried to forge a function in parsing time, but
> couldn't. What am I doing wrong, and how can one do such a thing?
> Maybe the problem is that I create no calls to that new function, what
> do you think? Anyway, I'm compiling with -O0, so I guess no
> optimization pass would remove my function just because it is not
> being used.
> 
> Thanks in advance,
> 
> ---
> Rodolfo Guilherme Wottrich
> Universidade Estadual de Campinas - Unicamp