>> If it is just to reach compatibility with the debugger, then I’d rather >> either just mandate a certain debugger or autoconf for what the current >> debugger supports. As of late people seem to just break the debugging >> experience with non-updated gdbs and assume that a newer gdb is used. > > You cannot do that: unlike the assembler and linker used, which are > often hardcoded into gcc, the debugger can easily be changed below the > compiler's feet, so to speak. Besides, on several platforms, you have > more than one debugger available (like gdb and dbx, or others), so this > isn't an option. Apart from that, the debugging experience when > e.g. emitting very recent DWARF extensions and trying to use them with a > gdb that doesn't understand them usually leads to some debug info > missing. In this case, emitting compressed debug with a debugger that > cannot read it leads to the debugger claiming (correctly, from its > point of view) that there's no debugging info present. I don't want to > tell users who come complaining `I compiled with -g, but my debugger > tells me there's no debug info present': `look, your debugger lies, it > is present, but it cannot read it'. That's a lot worse than the > DWARF extensions scenario above. >
Agreed :) FWIW it's already a gas/assembler option, I'm curious about wanting to expose it via the compiler? > On top of all that, compressed debug is a tradeoff: in some cases it may > be worth it to save space on debug info if disk space is at a premium > for some reason (e.g. for release builds), but in others you want to > compile as fast as possible, but assembling and linking compressed debug > takes more CPU time. Otherwise we could just as well default to -Os, > telling our users it's better for them since it generates faster and > smaller code, not minding the compile time cost and worse debugging > experience. > FWIW I've found in some limited timing that compression is nearly always worth it here at Google - even for compile time given the cost of writing files versus cpu time. Might be worth making it a default at some point in the future and making sure the option is invertible. -eric
