[LLVMdev] Var Args on X86-64

David Meyer pdox at google.com
Tue Jun 22 14:55:29 PDT 2010

Hello all,

I wish to get the va_arg instruction working on X86-64 Linux.  This requires
implementing VAARG lowering for X86-64.

I am fine with implementing it, but I am unsure of what approach I should
take. The straightforward option is to add the DAG nodes required to perform
the operation during lowering. (in X86TargetLowering::LowerVAARG()).
 However, the resulting code will be relatively long to accommodate the
complexity of what va_arg must do. It would be easier to operate on a higher
level, for example, by implementing va_arg in LLVM assembly. Is it possible
(or preferable) to implement an intrinsic (va_arg) using target-specific
llvm assembly?

 David M
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20100622/c31616f7/attachment.html>

More information about the llvm-dev mailing list