This simplifies the calling convention and consolidates the call frame stack
and value stack into a single stack.
As a result, the cost of function calls decreases because we now don't need
to check the boundary twice (value and call frame stacks) at each function call.
The following is the result of the benchmark for recursive Fibonacci
function in integration_test/bench/testdata/case.go, and it shows that
this actually improves the performance of function calls.
[amd64]
name old time/op new time/op delta
Invocation/compiler/fib_for_5-32 109ns ± 3% 81ns ± 1% -25.86% (p=0.008 n=5+5)
Invocation/compiler/fib_for_10-32 556ns ± 3% 473ns ± 3% -14.99% (p=0.008 n=5+5)
Invocation/compiler/fib_for_20-32 61.4µs ± 2% 55.9µs ± 5% -8.98% (p=0.008 n=5+5)
Invocation/compiler/fib_for_30-32 7.41ms ± 3% 6.83ms ± 3% -7.90% (p=0.008 n=5+5)
[arm64]
name old time/op new time/op delta
Invocation/compiler/fib_for_5-10 67.7ns ± 1% 60.2ns ± 1% -11.12% (p=0.000 n=9+9)
Invocation/compiler/fib_for_10-10 487ns ± 1% 460ns ± 0% -5.56% (p=0.000 n=10+9)
Invocation/compiler/fib_for_20-10 58.0µs ± 1% 54.3µs ± 1% -6.38% (p=0.000 n=10+10)
Invocation/compiler/fib_for_30-10 7.12ms ± 1% 6.67ms ± 1% -6.31% (p=0.000 n=10+9)
Signed-off-by: Takeshi Yoneda <takeshi@tetrate.io>
