How to repeat AST/Generic analysis

["xunilwithkrow" <xunilwithkrow at gmail dot com>]

Hi,

As we all know, usually, when we compile a souce file, there is one-pass or multiple-pass AST/Generic analysis, but when I say I want to repeat AST analysis , it's not about I intend to have multiple pass analysis. In this point, I'd like to repeat the whole thing even it's multiple pass.

So my problem is in c program when I find some kind of struct object is initialized in "compound literial " way, I want to do some change to the type itself. the scenario is much like:

struct Foo {
int* a;
char b;
int c;
...
};

........

int main(void) {
struct Foo tmp = { NULL, 'b', 10 ... };     // compound literial initialization

.....
}

When I find a object called tmp with type Foo, I intend to do some change in Foo itself ( in AST level). But as I skim gcc source code, I found the call order like this:
(Gcc-4.2.4   c-parser.c )

c_parser_declaration_or_fndef {
........
c_parser_declspecs      // line 1264  deal with the struct Foo declaration 
........
c_parser_initializer       //  line 1341  deal with the object tmp declaration
.......
}

Here you can see the problem, when I found tmp declaration, I already can't do nothing about struct Foo.  So if you guys have any better idea to let me do the change, just let me know : ) 

Or I get an idea which is repeating AST analysis. In first analysis, I record such struct type  to a list when I found the compound literial case. Then I can do change to these type in second AST analysis. 

How to repeat ?  First, I get the call stack:

main ()                   main.c
toplev_main ()         toplev.c
 general_init ()          toplev.c
  decode_options ()    toplev.c
   do_compile()            toplev.c
    compile_file()            toplev.c
     lang_hooks.parse_file () toplev.c
      c_parse_file ()               c-parser.c
       c_parser_tranlation_unit () c-parser.c
        c_parser_external_declaration () c-parser.c
          c_parser_declaration_or_fndef () c-parser.c
           finish_function ()                       c-decl.c

Then I tried to add second AST analysis from toplev_main () to c_parser_file () with doubling  the next level call, for example, in do_compile () , I let compile_file () called twice , then I all get " segmentation fault" from crtstuff.c line 348 
CRT_CALL_STATIC_FUNCTION (INIT_SECTION_ASM_OP, frame_dummy)

I learn some knowledge about crtstuff.c but can't get the point. So my problem is what this crtstuff.c really is , why double calling causes error and most important thing,  How to repeat analysis safely ?


Thanks

2009-07-06