[LLVMdev] question on generating dwarf metadata

[Bagel]

I am writing a front end for a new language and am having trouble generating 
the DWARF debugging information.  I'm outputting llvm assembly source so I'm 
trying to generate the "!metadata" stuff.

I have found the document <http://llvm.org/docs/SourceLevelDebugging.html> a 
helpful start, as far as it goes.  However, it doesn't quite match what I see 
clang produce when I use the flags "clang -g -S -emit-llvm ..." in all cases. 
And it is incomplete, for example, how does one deal with a function that 
returns multiple values?

I seem to get different results when I feed the .ll file to llc than when I 
feed it the clang, clang gives error messages when it doesn't like the metadata 
structure, llc appears not to do so.

Is there another document I should look at?

Should I be looking at source code?  Where are the structures that start with 
DW_TAG's parsed?

In general, what's resources does a front end implementer have in order to 
understand how to generate the DWARF stuff via llvm assembly source?

thanks, bagel