cmd/internal/obj/wasm,cmd/link/internal/wasm: add fast path for writeUleb128
While building a simple hello world binary, there are total 858277 calls
to writeUleb during the assembler phase out of which 836625 (97%) are less than 7 bits.
Using a simple micro-benchmark like this:
func BenchmarkUleb(b *testing.B) {
var buf bytes.Buffer
for i := 0; i < b.N; i++ {
writeUleb128(&buf, 42)
buf.Reset()
}
}
We get the following results with the fast path enabled.
name old time/op new time/op delta
Uleb-4 8.45ns ± 2% 7.51ns ± 2% -11.16% (p=0.000 n=10+10)
Applying the time taken to the number of calls, we get roughly 6% improvement
in total time taken for writeUleb128.
We also apply the change to the function in linker to make it consistent.
Change-Id: I9fe8c41df1209f5f3aa7d8bd0181f1b0e536ceb5
Reviewed-on: https://go-review.googlesource.com/c/go/+/201177
Run-TryBot: Agniva De Sarker <agniva.quicksilver@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>