What's that "GNU/Linux" in the beginning? [LWN.net]

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

Posted Jan 4, 2007 20:37 UTC (Thu) by dwheeler (subscriber, #1216)
In reply to: What's that "GNU/Linux" in the beginning? by gnb
Parent article: The Ultimate Distro (Linux Journal)

tcc is quite usable, but it's not a gcc replacement. tcc parses the statements and nearly immediately generates assembly that implements that statement, with VERY little optimization. The good side: tcc compiles VERY quickly, in some cases 10x faster than gcc. Indeed, there's a demo "FASTBOOT" that boots the tcc compiler, which then compiles and runs the Linux code from source (!). The downside: tcc code runs VERY slowly compared to gcc-generated code. By design, tcc generates something that works, but it doesn't have any of the intermediate structures that make good optimization possible. Granted, tcc-generated code runs fast enough for many purposes. But most users NEVER compile programs, and constantly run them, so trading away run-time performance is often not worthwhile. That said, tcc is very good for some purposes. I used it for my work to counter the trusting trust attack. tcc had some bugs, and the primary developer isn't doing much maintenance of tcc (because he's busy with other projects like QEMU), which is another problem. I some others are doing some maintenance of tcc.

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

Posted Jan 5, 2007 19:38 UTC (Fri) by landley (subscriber, #6789) [Link]

I've got my own mercurial repository which has turned into a semi-fork:

http://landley.net/hg/tinycc

But I've got too many other things going on to want to become the
project's new maintainer right now. The old maintainer (Fabrice) has his
hands full with QEMU.

And it does do a little optimization, simple constant propogation and
such. It wouldn't be that hard to shoehorn dead code elimination in
there, which makes it a lot more usable for things like the linux kernel
and busybox (where dead code elimination is relied on by the configure
system to avoid lots of hideous #ifdefs).

Getting the linker to garbage collect is a larger project...

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

Posted Jan 9, 2007 17:20 UTC (Tue) by nix (subscriber, #2304) [Link]

Doing DCE properly requires a lot of dataflow analysis which would be really rather hard to ram into tcc (at least it would have been the last time I looked at it).