[cfe-dev] Cleaning up the clang::driver::toolchains::Linux mess?

[David Chisnall]

Chris did some brief design (search for Universal Driver) a while ago, but it didn't get implemented.  I'd love to see the toolchain descriptions moved out into a config file, so when a Linux distro decides to randomly move all of their paths around again users just need to update a config file specifying the default locations, and users can create cross-compile toolchain descriptions just by editing a config file, without needing to hack on clang.

David

On 14 Jun 2011, at 00:03, Anders Kaseorg wrote:

> clang 2.9 hardcodes a huge list of GCC versions and paths and distro 
> release files in /etc just to find where GCC keeps its libraries and 
> include files on Linux.  This was introduced in 
> http://llvm.org/viewvc/llvm-project?view=rev&revision=118382 , and it’s 
> been patched up several dozen times since then with uglier and uglier 
> distro-specific hacks.
> 
> Lately this has been causing trouble for Debian and Ubuntu development 
> releases, which have been transitioning to multiarch paths for GCC, such 
> as /usr/lib/i386-linux-gnu/gcc/i486-linux-gnu/4.6.1; see 
> http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=629861 .  But more 
> fundamentally, it seems fragile, unmaintainable, and most other kinds of 
> wrong.  It’s guaranteed to break again every time a new GCC version or a 
> new distro release comes out, and even if clang gets fixed promptly, not 
> every distro has the resources and energy to package a new version of 
> clang every time that happens.
> 
> Is there a sane way to find these paths?  It seems GCC has an option to 
> just output them:
> 
> $ gcc -print-file-name=crtbegin.o 
> /usr/lib/i386-linux-gnu/gcc/i486-linux-gnu/4.6.1/crtbegin.o
> 
> This would preferably happen at clang’s configure time so the packager can 
> override the autodetection if it fails for some reason.  It might even be 
> possible to parse all the necessary distro-specific flags (-z relro, 
> --hash-style=gnu, etc.) out of `gcc -dumpspecs`.
> 
> Anders
> 
> _______________________________________________
> cfe-dev mailing list
> cfe-dev at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev