On Sunday 15 June 2008 23:38:12 Enrico Weigelt wrote: > * Rob Landley <rob@xxxxxxxxxxx> schrieb: > > Did you try my FWL project? :) > > > > http://landley.net/code/firmware > > hmm, doesnt look like supporting sysroot ... It doesn't use sysroot. It makes the compiler relocatable using an updated version of the old uClibc wrapper script, which rewrites each glibc command line to start with --nostinc --nostdlib and then adds the correct paths back in from the ground up. Have you ever run gcc under strace? Or worse, looked at the gcc path logic source code? It's a mess. It gets paths from ./configure options, it gets paths from spec files, it adds hardwired paths in the C source code, it checks enviroment variables to get more paths, and this isn't counting the paths you tell it on the command line. Every time they gave up on the previous approach because it was obviously unworkable, they NEVER REMOVED ANYTHING. They just added yet another layer on top of it, falling back to the previous one each time. It never occurred to them that people would want to make it NOT check paths like /usr/include. They just keep piling on more and more, appending to a big vararray and never removing anything. Do you know how sysroot is implemented? It still hardwires absolute paths into the binary, but then it does a string compare with the start of the hardwired path so it knows how much to trim off when substituting another path instead. I once tried to work up a patch to remove the obsolete or clearly defective parts of the gcc path logic, but when my patch got large than 10,000 lines I gave up and went to a wrapper script. The only way to make the gcc path logic reliable is to NOT USE IT. Hence the wrapper script to tell it to ignore all the paths it _thinks_ it knows, and check in exactly these places (and only those places) instead. Then you can run the result under strace without wanting to throw up quite so much. > cu Rob -- "One of my most productive days was throwing away 1000 lines of code." - Ken Thompson. -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
