Displaying 2 results from an estimated 2 matches for "passbyvalarg".
2017 Mar 07
2
Current preferred approach for handling 'byval' struct arguments
As many of you will know, handling of struct arguments in LLVM is
actually slightly more fiddly than you might expect. For targets where
aggregates are always passed on the stack it's easy enough, the Clang
ABI code marks these arguments as byval and the call lowering code in
LLVM will copy the object to the stack when needed. There are more
options for when the target has more complex ABI
2017 Mar 08
3
Current preferred approach for handling 'byval' struct arguments
...owering still has logic to split a byval aggregate between
the stack and registers (why not I have to say looking at
AArch64ISelLowering and the clang code it's not immediately obvious to
me where aggregates get split between the stack and registers (which
is quite clear in MipsTargetLowering::passByValArg). What am I missing
here?
It seems to me there are a few possibilities for targets where the ABI
indicates aggregates may be passed in registers:
* Clang always passes aggregates as byval, LLVM call lowering may
assign some or all of the aggregate to registers. Seemingly nobody
does this
* Clang...