Hi Jakub, On Thu, Apr 19, 2018 at 12:31:03AM +0200, Jakub Wilk wrote: > GCC no longer looks for "as" in the directory specified by the -B option:
Yes, I asked Matthias for passing --with-as to gcc. > This breaks afl-gcc (part of the afl package), which uses the -B option to > talk GCC into using a hacked version of the assembler. > > I guess this is fallout from fixing #895251. I am sorry for having broken afl-gcc along the way and imposing the work of discovering why on you. > Previously it worked like this: > > $ gcc --version | head -n1 > gcc (Debian 7.3.0-15) 7.3.0 > > $ strace -f -o '| grep -w as' gcc -B/foo/bar/ -c -x c /dev/null > 3770 stat("/foo/bar/x86_64-linux-gnu/7/as", 0x7ffd82351450) = -1 ENOENT > (No such file or directory) > 3770 stat("/foo/bar/x86_64-linux-gnu/as", 0x7ffd82351450) = -1 ENOENT (No > such file or directory) > 3770 stat("/foo/bar/as", 0x7ffd82351450) = -1 ENOENT (No such file or > directory) > 3770 stat("/usr/lib/gcc/x86_64-linux-gnu/7/as", 0x7ffd82351450) = -1 > ENOENT (No such file or directory) > 3770 stat("/usr/lib/gcc/x86_64-linux-gnu/7/as", 0x7ffd82351450) = -1 > ENOENT (No such file or directory) > 3770 stat("/usr/lib/gcc/x86_64-linux-gnu/as", 0x7ffd82351450) = -1 ENOENT > (No such file or directory) > 3770 stat("/usr/lib/gcc/x86_64-linux-gnu/7/as", 0x7ffd82351450) = -1 > ENOENT (No such file or directory) > 3770 stat("/usr/lib/gcc/x86_64-linux-gnu/as", 0x7ffd82351450) = -1 ENOENT > (No such file or directory) > 3770 > stat("/usr/lib/gcc/x86_64-linux-gnu/7/../../../../x86_64-linux-gnu/bin/x86_64-linux-gnu/7/as", > 0x7ffd82351450) = -1 ENOENT (No such file or directory) > 3770 > stat("/usr/lib/gcc/x86_64-linux-gnu/7/../../../../x86_64-linux-gnu/bin/x86_64-linux-gnu/as", > 0x7ffd82351450) = -1 ENOENT (No such file or directory) > 3770 > stat("/usr/lib/gcc/x86_64-linux-gnu/7/../../../../x86_64-linux-gnu/bin/as", > 0x7ffd82351450) = -1 ENOENT (No such file or directory) > 3773 execve("/usr/local/bin/as", ["as", "--64", "-o", "null.o", > "/tmp/ccFhN057.s"], 0xbe46d0 /* 24 vars */) = -1 ENOENT (No such file or > directory) > 3773 execve("/usr/bin/as", ["as", "--64", "-o", "null.o", > "/tmp/ccFhN057.s"], 0xbe46d0 /* 24 vars */ <unfinished ...> > > As you can see, GCC was already looking for "as" in a triplet-specific > directory. So perhaphs gcc-7 should ship an appropriate symlink in > /usr/lib/gcc/<triplet>/7/, instead of hardcoding path to "as" at configure > time? Your suggestion makes a lot of sense. The devil is in the detail though: * Does it work the same way for ld? * Do cross toolchains also need such a symlink? * If yes, where to place it? (They use a different directory layout.) * Which make variable contains the correct path? Plan: * I think it is reasonable to simply revert #895251 for the time being. That should fix this bug. * I'll look into the details and will propose an improved patch. Helmut