gcc c grammar

[Eduardo Cruz]

Hello, my name is Eduardo Cruz. I am an studen.t of Computer Science
at the State University of Maringa, in Brazil.
One of our teachers gave us a work in wich we are supposed to modify
the c language to support some parallel programming stuff.
I want to modify the gcc c frontend to support these features.
I thought gcc used bison as a syntax analyser, but when I saw the gcc
c-parser source code I realized that it didn't use bison.
I read in the gcc mailist that gcc now has a recursive descent parser.
Do you have any document that contains the grammar implemented in gcc c-parser?
If you have, can you send it?
It would be easier to make the proprer changes in the grammar if I
have this document, because I won't have to understand the grammar
reading the source code.

Thank you very much for your atention

Re: GCC C FRONT END EXPLANATION

[Eduardo Cruz]

hey, could you guys explain me something?
in c-parser.c

in c_parser_direct_declarator, when a function name is being parsed, this if:

if (c_parser_next_token_is (parser, CPP_OPEN_PAREN))

is true, and inside this if:

  c_parser_consume_token (parser);
  attrs = c_parser_attributes (parser);

so it consumes the token "(", and then calls c_parser_attributes to
check the parameters of the function

but in c_parser_attributes this is made in the beggining of the loop:

  c_parser_consume_token (parser);
  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
{
  parser->lex_untranslated_string = false;
  return attrs;
}

I don't understand, after the consumed token "(" there will be a
variable type right?
why it consumed the token without checking it?
and why does it require the token "(" ? aren't we inside the function
parameters list?

that's all for a while
thanks

2009/3/20 Dave Korn :
> Guilherme Puglia wrote:
>
>> But thanks to everybody.
>> I'll read the gcc docs in the source code!
>
>
>  The C parser starts in gcc/c-parser.c.  There are a bunch of lexing routines
> at the top, then you'll see a whole bunch of c_parser_X routines which
> handle the individual grammar constructs.  Each one has a commnent at the top
> describing the syntax elements it parses and referring to the paragraph of the
> C standard where they're defined.  (If you don't have a copy of the C standard
> handy, google "n1256.pdf").  Good luck!
>
>    cheers,
>      DaveK
>
>

lookup_name

[Eduardo Cruz]

does the function lookup_name distinguish the identifier between
different contexts?

for example

void func1()
{
   int foo;
}

void func2()
{
   int foo;
}

if I call lookup_name with the foo ident-tree while parsing these
functions, will it return different decl-tree nodes?

thanks

Re: lookup_name

[Eduardo Cruz]

> I assume you mean the function in the C frontend, in c-decl.c.
thats correct!

thanks a lot!

2009/4/7 Ian Lance Taylor :
> Eduardo Cruz  writes:
>
>> does the function lookup_name distinguish the identifier between
>> different contexts?
>
> I assume you mean the function in the C frontend, in c-decl.c.  That
> function looks up the name in the current scope, so, yes, it will return
> different DECL nodes when appropriate.
>
> Ian
>