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?)
38 lines
465 B
Text
38 lines
465 B
Text
C
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C-unwind
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Rust
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aapcs
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aapcs-unwind
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avr-interrupt
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avr-non-blocking-interrupt
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cdecl
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cdecl-unwind
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cmse-nonsecure-call
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cmse-nonsecure-entry
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custom
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efiapi
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fastcall
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fastcall-unwind
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gpu-kernel
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msp430-interrupt
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ptx-kernel
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riscv-interrupt-m
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riscv-interrupt-s
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rust-call
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rust-cold
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rust-invalid
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rust-preserve-none
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stdcall
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stdcall-unwind
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system
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system-unwind
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sysv64
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sysv64-unwind
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thiscall
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thiscall-unwind
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unadjusted
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vectorcall
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vectorcall-unwind
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win64
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win64-unwind
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x86-interrupt
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