You're missing at least (a) structure padding/alignment; (b) debug info; (c) name mangling. LLVM abstracts over some of the differences but definitely not all.
In any case, just having a Rust compiler isn't very useful; you need a standard library (or at least libcore) to do anything interesting with the language, and that's where most of the porting effort comes in.
In any case, just having a Rust compiler isn't very useful; you need a standard library (or at least libcore) to do anything interesting with the language, and that's where most of the porting effort comes in.