6db94dbc25
This is the conceptual opposite of the rust-cold calling convention and
is particularly useful in combination with the new `explicit_tail_calls`
feature.
For relatively tight loops implemented with tail calling (`become`) each
of the function with the regular calling convention is still responsible
for restoring the initial value of the preserved registers. So it is not
unusual to end up with a situation where each step in the tail call loop
is spilling and reloading registers, along the lines of:
foo:
push r12
; do things
pop r12
jmp next_step
This adds up quickly, especially when most of the clobberable registers
are already used to pass arguments or other uses.
I was thinking of making the name of this ABI a little less LLVM-derived
and more like a conceptual inverse of `rust-cold`, but could not come
with a great name (`rust-cold` is itself not a great name: cold in what
context? from which perspective? is it supposed to mean that the
function is rarely called?)
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|---|---|---|
| .. | ||
| backend-has-zstd-unstable.rs | ||
| backend-has-zstd-unstable.stderr | ||
| host.rs | ||
| host.stdout | ||
| invalid-target.rs | ||
| invalid-target.stderr | ||
| macos-target.rs | ||
| macos-target.stdout | ||
| print-calling-conventions.rs | ||
| print-calling-conventions.stdout | ||
| print-lints-help.rs | ||
| print-lints-help.stderr | ||
| stability.rs | ||
| supported-crate-types.linux.stdout | ||
| supported-crate-types.musl.stdout | ||
| supported-crate-types.rs | ||
| supported-crate-types.wasm.stdout | ||