[LLVMdev] New TargetSpec 'llvmnote'

[Sandeep Patel]

On Wed, Feb 23, 2011 at 2:46 AM, Chris Lattner <clattner at apple.com> wrote:
>
> There is recently a discussion on the LLDB list about how to deal with targets, and our current mismash of llvm::Triple and the various subclasses of TargetSubtarget leave a lot to be desired.  GNU target triples are really important as input devices to the compiler (users want to specify them) but they aren't detailed enough for internal clients.
>
> Anyway, in short, I think that we should unify the variety of code we have to deal with this stuff into a new TargetSpec class.   I don't have any short-term plan to implement this, but I wrote up some of my thoughts here:
> http://nondot.org/sabre/LLVMNotes/TargetSpec.txt
>
> Remember that this isn't intended to be something users deal with, it's just an internal implementation detail of the compiler, debugger, nm implementation, etc.

Bitcode currently does not carry enough options information to handle
LTO. For example, if you use -O1 for a particular translation unit but
-O4 for the rest of them, that information isn't saved and provided to
LTO when the actual optimization is happening. Similarly, some options
like soft-float/hard-float aren't preserved. We should consider these
issues while solving this.

deep