[LLVMdev] Noob Backend Orientation

[Brian Mokrzycki]

Hi all,

	I'm new to the project and will probably ask quite a few obvious questions, so please, bare with me.  

	I'm trying to get my bearings straight as to the general path forward for producing a backend for a custom DSP processor.  Currently, I have a port of binutils and a basic simulator (based on SID).  I want to make it easier for software engineers to produce code for this architecture so I'm moving onto the next phase by attempting a C compiler, so here I am.

	First, I would rather not maintain two different descriptions of the assembly/ISA specification, one in binutils/SID (CGEN) and another in LLVM.  I have found some posts about the LLVM MC project, that it can essentially produce an inline or standalone assembler, but is the MC project ready for prime-time?  Should I invest my time going this route?  It's hard to get a sense of what direction the project is moving in.

	Second, related to the previous, if I were to only maintain the assembly/ISA description in LLVM, can LLVM produce a simulator to execute target specific machine code binaries?  I realize that you can, in theory, translate the ll assembly to the host machines processor architecture as a pseudo-simulation, but this doesn't give you hardware specific information about your real target machine, such as what is stored in register r6 at breakpoint 10. 

	Lastly,  the DSP processor is a VLIW/EPIC machine.  I assume that this fact is going to produce a few hiccups when creating the LLVM backend, just like it did when I was doing the binutils port.  Any words of wisdom would be very welcome on this front.

Thanks,

-Brian