Howdy, I'm a contributor to the Parrot project which is a virtual machine for dynamic languages including Perl 6. One of the problems we've been facing is that the bytecode does not contain a debug segment for preserving high-level information about the original source code. Therefore, I've begun work on a watered-down version of DWARF to help fill this gap. Designing the format itself has been fairly easy but now I must consider the actual implementation.
That is why I've come to you guys. Considering that GCC supports several debug formats (including DWARF), I figured that the GCC Project would be the best place to inquiry about a few design issues. I'd like to know at what stage during compilation is debug data collected and subsequently stored in the object file? Is it a multi-stage process? Perhaps the parser collects some high-level information which passes it to the code generator for further analysis which passes it again to the linker/loader for even further low-level analysis? Or is there a single stage dedicated to collecting debug data; perhaps after linking? I envisioned it as a multi-stage process but I don't want to make any assumptions. I've tried to gain some knowledge by digging through the GCC source but haven't come up with much other than the values of the DW_* constants which isn't that important. Are there any files in particular I should be looking at? If any of you are DWARF experts, I would really appreciate your advice. Thanks for the help! -- - Kevin Polulak (soh_cah_toa)
