[LLVMdev] Targeting low level embedded

[Tom Hawkins]

I'm new to LLVM and I'm trying to set it up to target a low level
embedded device with no OS.  Therefore the final program needs to
perform variable initialization and be located at a certain address
location.  Here is my basic flow:

Compile C to bytecode:
$ llvm-gcc -emit-llvm -c src1.c src2.c src3.c

Consolidate to one bytecode file:
$ llvm-link -o all.o src1.c src2.o src3.o

Emit assembly code:
$ llc -march=ppc32 -o all.s all.o

Assemble to machine code:
$ powerpc-eabi-as -o all.elf all.s

Relocate sections to target specific addresses:
$ powerpc-eabi-ld -T sections.ld -o relocated.elf all.elf

... then convert to an s-record and flash the device.

A few questions...

1. Is this the right approach?
2. Does llvm-gcc insert initialization code?  It doesn't look like it,
but I may be missing something.
3. What is the difference between llvm-link and llvm-ld?  Does
llvm-link do inter module optimization?
4. Can llvm-link or llvm-ld perform any memory placement, or does this
fall on binutils ld?

Thanks for any help!

-Tom