encoding/gob: avoid a pointer to wireType in typeInfo
wireType itself is just a struct with seven pointer fields,
so an indirection doesn't feel necessary to noticeably reduce the amount
of memory that typeInfo takes for each Go type registered in gob.
The indirection does add a small amount of overhead though,
particularly one extra allocation when registering a type,
which is done a number of times as part of init.
For consistency, also update wireTypeUserInfo to not use a pointer.
Measuring via one of the end-to-end benchmarks and benchinit:
goos: linux
goarch: amd64
pkg: encoding/gob
cpu: AMD Ryzen 7 PRO 5850U with Radeon Graphics
│ old │ new │
│ sec/op │ sec/op vs base │
EndToEndPipe-16 736.8n ± 5% 733.9n ± 5% ~ (p=0.971 n=10)
EncodingGob 177.6µ ± 0% 173.6µ ± 0% -2.27% (p=0.000 n=10)
geomean 11.44µ 11.29µ -1.34%
│ old │ new │
│ B/op │ B/op vs base │
EndToEndPipe-16 1.766Ki ± 0% 1.766Ki ± 0% ~ (p=1.000 n=10) ¹
EncodingGob 38.47Ki ± 0% 38.27Ki ± 0% -0.50% (p=0.000 n=10)
geomean 8.241Ki 8.220Ki -0.25%
¹ all samples are equal
│ old │ new │
│ allocs/op │ allocs/op vs base │
EndToEndPipe-16 2.000 ± 0% 2.000 ± 0% ~ (p=1.000 n=10) ¹
EncodingGob 652.0 ± 0% 642.0 ± 0% -1.53% (p=0.000 n=10)
geomean 36.11 35.83 -0.77%
¹ all samples are equal
Change-Id: I528080b7d990ed595683f155a1ae25dcd26394b2
Reviewed-on: https://go-review.googlesource.com/c/go/+/479398 Reviewed-by: Ian Lance Taylor <iant@google.com> Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Daniel Martí <mvdan@mvdan.cc> Reviewed-by: Rob Pike <r@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>