[llvm-commits] [llvm-gcc-4.2] r53113 - /llvm-gcc-4.2/trunk/gcc/config/darwin.h

[Eric Christopher]

On Jul 7, 2008, at 10:19 AM, Evan Cheng wrote:

> It would be nice if someone with configure foo can help with this.  
> Perhaps Eric?

Sure. There are a few ways you can go about this:

a) add a configure specific flag --enable-llvm-lto or something that  
will be off
by default or something of that sort.

or (icky)

b) basically check for a version number of ld that will support the  
flag. there are some examples in gcc/configure.ac that show how to do  
this for gnu ld

or (preferred)

c) add support to ld to print out the command line options it  
recognizes (--help maybe? -h?) and then use something simple like:

         # Check if linker supports -mllvm
         if $gcc_cv_ld --help 2>/dev/null | grep mllvm > /dev/null; then
                 gcc_cv_ld_llvm=yes
         fi


You'll need a little more wrapper around that, but this last is the  
easiest way to go if someone bugs Nick to put option listing support in.

-eric