[cxx-abi-dev] Inlining requirements for ABI functionality

[John McCall]

On Dec 6, 2011, at 1:56 PM, Dennis Handly wrote:
> Our ia64 compiler has thunks that just branch to the normal functions.

This-adjustment thunks can get away with tail-calling / branching to the normal
function, but covariant-return thunks must do an actual call.  That's a problem
(in every psABI that I know) when the function is variadic, because there's now
a pointer of extra information (the original return address) and nowhere in the
call frame to put it.  Clang just gives up and inlines in this case.

John.