What's that "GNU/Linux" in the beginning?

What's that "GNU/Linux" in the beginning?

Posted Jan 9, 2007 17:34 UTC (Tue) by nix (subscriber, #2304)
In reply to: What's that "GNU/Linux" in the beginning? by landley
Parent article: The Ultimate Distro (Linux Journal)

The path search logic has just got a little cleaner :)

Of course it makes a difference what the build system is: it needs to know if the files it builds to incorporate into the (many) little-language code generators it builds and uses during the build process can also be linked into the final compiler binary. It needs to know if a three-stage bootstrap is even *possible* or whether `make' should invoke a one-stage build (`make bootstrap' is so 2004, y'know, it's just `make' like every other package these days). It needs to know if there are any differences between e.g. the floating-point representation used on the build and host system. It needs to know if it can run configure tests to determine properties of the host system, or whether it has to assume safe defaults (you wouldn't want it doing the latter in the common case). (tcc doesn't need to do this to such a degree because it doesn't come with a bunch of runtime libraries. Also it doesn't need to cater for the nest of snakes which is exception unwinding and the related nest which involves shared libraries, destructor invocation order, and so forth.)

And as for the distinction between a native and cross-compiler being artificial, well, in *theory* a compiler could be made that didn't care what its host system was, but in practice unless it is to be intolerably slow it *must* know the machine's native types at least (which varies between OS and platform because it is ABI-dictated, and on many platforms GCC/binutils do not set the ABI). (A sufficiently nonportable compiler could avoid paying attention to systems that don't have IEE754 floating point, but GCC is not that nonportable, or at least at one point it wasn't: I'm not sure how many non-IEEE754 systems are left. I think some are, discounting ia32/x87 of course with its horrible `extended precision' mess, which is slowly becoming legacy anyway as SEE fpmath takes over.)

The `target triplet' stuff GNU has got is a bit ugly, but if you consider it to be an `ABI-and-OS-and-core-libraries indicator' (which is basically what it is), then it makes a bit of sense. uClibc just needed a new target triplet/quadruplet (and, oh look, *-*-*-uclibc works perfectly well).

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