GCC world tour

[Andi Hellmund]

Hey Kevin,
> Hi,
>
> Could anyone suggest some good tourist stops in GCC (i.e. good
> functions to set breakpoints at while "debugging" a simple compile to
> learn the inner workings of the beast)? If I wanted to visit the C
> parser, what is that called?
That's really hard to answer. As you said, GCC is a beast with a _lot_ 
of different components. I used to start with just "main" and start 
working through the very high-level components like option parsing, 
front-end interaction, middle-end.

Some interesting functions could be: gimplify_function_tree (GENERIC to 
GIMPLE), cgraph_optimize (that's where the optimization passes of the 
middle-end start). If you are further more interested in the various 
(optimization) passes of GCC, I would possibly search the source code 
for "struct *opt_pass" (e.g. struct simple_ipa_opt_pass) which contains 
the descriptions for the (optimization) passes, including the functions 
getting executed.
> I was playing with the -### option. There is a wiki debugging entry
> that describes running cc1 using the driver:
>
> gdb --args `gcc/xgcc -### -Bgcc -O2 -march=pentium3
> -fomit-frame-pointer -S -fverbose-asm -dA -Q -fmem-report
> ../../gcctest1.i 2>&1|grep cc1|tr -d '"'`
>
> I had to add the "tr -d '"' (a ' " ') or it would not work? Says it
> can't find "gcc/cc1". Am I doing something wrong? Or is this a
> "feature" of Debians gdb?
I think that you are doing something wrong. This command worked for me 
perfectly. Does the file gcc/cc1 exist? If yes, I would possibly start 
to just run the command in ``, check the result, execute this command in 
the shell and finally feed this command into gdb --args. Maybe there's 
somewhere a simple typo ...

Best regards,
Andi