[LLVMdev] IMPORTANT: Switch-over to new C front-end on X86

[Chris Lattner]

This is a note to let everyone know that I just changed the LLVM build
scripts to use the new C front-end for everything (on X86).  If you are
doing development on X86, you *must* make the following changes to your
setup:

1. Change your llvm-gcc symlink (or alias, or whatever you use) to point
   to ~lattner/local/x86/llvm-gcc/bin/gcc
2. Add the following environment variable to your startup scripts:
   setenv LLVM_LIB_SEARCH_PATH /home/vadve/lattner/local/x86/llvm-gcc/bytecode-libs

If you don't do this, things will probably break in horrible, unthinkable
ways (or maybe not, but they certainly won't work nicely).  If you're
curious, the environment variable specifies the directory to use for the
LLVM equivalent of /usr/lib: the location of system librarys like libc and
libm.

In order to enable this, I have been fixing bugs in lots of places, such
that now all programs in test/Programs/SingleSource and
test/Programs/MultiSource compile and execute correctly with LLVM on X86
(using both the C back-end and the JIT).  Therefore, you can now go into
either directory and type 'make DISABLE_LLC=1' and you should get a clean
test run at all times.

At this point there are still some bugs that prevent legal programs from
compiling, but there should be no miscompilation bugs.  If you can
successfully compile a program with the LLVM compiler, but it doesn't
work, I _definately_ want to know about it.  If it doesn't compile, please
also let me know so that I can make sure it's one of the (2) known
problems I still have outstanding.

Next I will be working on getting Sparc to the same point so that I can
switch over to using the new C front-end there without fear of introducing
regressions.  I'll send out another brief email when that time comes, and
then move on to checking to see if SPEC works.

Have fun LLVM'ing.

-Chris

-- 
http://llvm.cs.uiuc.edu/
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