noone at nowhere.com
Fri Jul 27 17:53:51 UTC 2018
On Friday, 27 July 2018 at 10:11:03 UTC, Jack Applegame wrote:
> There is one strange thing.
> Should the compiler to insert the return command for naked
> I suppose it shouldn't.
> Looks like LDC removes the prologue/epilogue, but not
> completely, leaving the return from function.
In this case I'd think it has to, you're even using an explicit
return statement. I'm not familiar with the ARM calling
convention wrt. call/return, but gcc emitting no return seems
very strange (where is it supposed to continue after the add
instruction? the next function in the final binary?!). Did you
test that it actually works as intended?
I updated the PR yesterday, so that LDC's pro-/epilogue is
excluded too, which allows the usage of params (not just in some
cases like yours together with -O). [Your sample doesn't work
anymore now, crashing the compiler, as it now requires __asm()
and/or inlineIR() to work with params.]
AFAIK, a return is required as we go through LLVM IR and not
directly to the assembler (which for example allows you to write
the function body in LLVM IR). Yesterday's variant probably
crashes if there's no explicit return (e.g., with __asm() and a
naked function returning void).
I take it this is just a toy example for gcc/LDC comparison, or
do you really need to omit a return instruction in real-world
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