[LLVMdev] Beginner needs some glue between Kaleidoscope and other docs

[SAYER Christian]

Hi Folks,
I am just starting to get familiar with the llvm framework, thank you at
first for this nice tool which seems really powerful!
I have studied so far the Kaleidoscope example and other docs at
llvm.org
and try to figure out which would be the "right" way (well I
suppose there are many) to integrate the framework into my compiler
project, but there is still quite a gap between the tutorial and the
multitude of things that can be found in the docs...

What I want to do:
The source language could be considered as a basic subset of C, with
some custom "instructions", and without expressions, only statements. I
write instructions here because most of the statements map quite
directly to the hardware. I would like llvm to do some optimizations
like constant propagation, loop optimization etc. , and register
allocation on the standard arithmetic/logic subset of instructions.
Finally, it should emit a (specified, non standard) assembler code.

What I think I'll have to do:
-straight forward parse and pass to llvm IR. Actually I don't even see
the need of an AST since there aren't any expressions to resolve.
Additionally, the source typically generated code.
At this point I think I'll have to extend the IRBuilder to support the
custom instructions.

-run standard optimization passes on the IR code. Add custom
optimization passes to support custom instruction optimization.

-add information and/or code about the target hardware (registers, ...)
to llvm to make it able to allocate registers.
add a backend to llvm to support my instruction set and assembler
syntax.
(i.e. write a lib/Target/MyProc)


Please, could you comment on this approach?
Given the fact that my source and target are way less complex than e.g.
C/x86, llvm should have enough (if not too many : ) facilities to
achieve this.

Thank you,
Christian