Can you recommend any good book or reference for backend implementation? I skimmed some compiler books but it seemed to be more about front-end, parsing, optimization etc.
Would you mind suggesting some books containing more about backend?
Thank you.
try here:
this project have a ebook (Compiler Construction: A Practical
Approach) that covers some backend code generation techniques.
So, the question that every once in a while is posed on this mailing
list:
What's the latest on llvm-java?
I couldn't get the CVS version to compile under LLVM 1.9.
I need to get Java class files to LLVM.
If anyone can just tell me how to get it to compile, that would be
great.
-Jimi
So, the question that every once in a while is posed on this mailing
list:What's the latest on llvm-java?
No work has been done on it for well over a year, maybe two years. The
person developing llvm-java stopped without finishing it and it can
barely run "hello world".
I couldn't get the CVS version to compile under LLVM 1.9.
It might compile with LLVM 1.7. It definitely won't with later
versions.
I need to get Java class files to LLVM.
There currently isn't a way.
If anyone can just tell me how to get it to compile, that would be
great.
You'd probably be better off spending time getting gcj in llvm-gcc to
work. Most of it is done already as llvm-gcc's support for C/C++/Obj-C
is already in place. gcj generates some tree codes that llvm-gcc
currently doesn't handle. To get it working, someone needs to implement
the delta between what is currently supported and what gcj needs.
You are right most compiler textbooks are very week in the codegen area. I would suggest reading "Building an Optimizing Compiler" by Morgan to get some background then start hacking on LLVM to learn the real thing! 
Evan
AFAIK the state is as it was back in March 2003. This thread is still
pretty accurate:
http://lists.cs.uiuc.edu/pipermail/llvmdev/2006-March/005286.html