On 2019-03-25 14:12 +0100, Pierre Labastie via lfs-dev wrote: > On 25/03/2019 10:34, Xi Ruoyao via lfs-dev wrote: > > On 2019-03-24 12:49 -0500, Bruce Dubbs via lfs-dev wrote: > > > On 3/24/19 12:20 PM, Xi Ruoyao via lfs-dev wrote: > > > > In r11250 DJ introduced several symlinks and GCC -isystem options for > > > > Glibc > > > > so > > > > it will use the final system location of system headers. When I was > > > > poking > > > > around Debian package build processes I found they were using -ffile- > > > > prefix- > > > > map > > > > to complete this goal. > > > > > > > > This has serveral advantages: > > > > > > > > 1. The instruction is simpler. > > > > 2. No risk of forgetting to remove the symlinks. > > > > 3. No /usr/include/limits.h issue. > > > > > > > > Is this OK to be commited into the trunk? > > > It looks OK to me. Go ahead. After you do, I will do a complete build > > > and double check. I wan tot update the kernel and iproute anyway. > > Commited at r11560. Just built a new LFS (overwriting my old LFS 8.1) to > > make > > sure it works. > > > > Strange thing: both methods (-isystem and -ffile-prefix-map) still left a > > few > > paths beginning with /tools/include. Open libc.so with vim, search > > "/tools", > > then we can see them. I'm not sure why. > I'm not sure either, but, according to the doc, the mapping is done > in very specific cases: > - first, it is when compiling a file _residing_ in the old directory > (here, /tools). > Then any reference to the old directory is replaced by the new directory > (here, /usr) in the _result_ of the compilation. > - second, only two types of substitutions are made: (i) in debugging > information, > and (ii) when processing the "__FILE__" and "__BASE_FILE" macros, > and also > "__builtin_FILE()" function during compilation. > > So it seems that any other reference to /tools is likely to remain, in > particular, > if a function whose source resides outside /tools, somehow references /tools
But I also tried the original approach (-isystem the symlinks in /usr). It also remains references to /tools, and the remained paths are exactly the same with -ffile-prefix-map. That's why I feels strange. If the original approach could eliminate every reference to /tools but -ffile- prefix-map can not, I won't do this change. -- Xi Ruoyao <xry...@mengyan1223.wang> School of Aerospace Science and Technology, Xidian University -- http://lists.linuxfromscratch.org/listinfo/lfs-dev FAQ: http://www.linuxfromscratch.org/faq/ Unsubscribe: See the above information page
