[llvm-dev] Automake Assembler Assumptions with LLVM-MC

[John Reagan via llvm-dev]

On Wed, May 18, 2016 at 01:10:50PM +0000, Daniel Sanders via llvm-dev wrote:
> It's my understanding that llvm-mc is intended to be a testing tool
> for LLVM developers rather than an assembler for end users. Users
> should be assembling with clang.

Not all LLVM users are clang users.  For example, we're using LLVM to build
OpenVMS cross-compilers to x86 for our porting effort.  We have our own set
of frontends.  We're using llvm-mc as our assembler for the lower level OS
code. 

We'll eventually port clang as well to bootstrap going forward, but OpenVMS
doesn't have the same kind of driver-style so even there, I can't just the
'clang' command to control assembly.

As for bug-for-bug compatibility in any sort of software, that's a tough choice.
Traditionally, I've resisted such pressure but sooner or later, I've had to give
in now and then.  As for the command line option matching, that is an area I
wouldn't attempt to match since such options vary greatly across platforms.

John