commit | 02ab8d1a1dc82ce019969221313bfa28911f54a1 | [log] [tgz] |
---|---|---|
author | Cherry Zhang <cherryyz@google.com> | Sat Apr 24 12:41:17 2021 -0400 |
committer | Cherry Zhang <cherryyz@google.com> | Fri Apr 30 00:08:50 2021 +0000 |
tree | a77a0e691546e7ccdb6177dd564e7b17fb8bd43d | |
parent | a9705e157beb51574233e23cc2e2a412d4681a15 [diff] |
cmd/compile, runtime: emit only GC data for stack objects Currently, for stack objects, the compiler emits metadata that includes the offset and type descriptor for each object. The type descriptor symbol has many fields, and it references many other symbols, e.g. field/element types, equality functions, names. Observe that what we actually need at runtime is only the GC metadata that are needed to scan the object, and the GC metadata are "leaf" symbols (which doesn't reference other symbols). Emit only the GC data instead. This avoids bringing live the type descriptor as well as things referenced by it (if it is not otherwise live). This reduces binary sizes: old new hello (println) 1187776 1133856 (-4.5%) hello (fmt) 1902448 1844416 (-3.1%) cmd/compile 22670432 22438576 (-1.0%) cmd/link 6346272 6225408 (-1.9%) No significant change in compiler speed. name old time/op new time/op delta Template 184ms ± 2% 186ms ± 5% ~ (p=0.905 n=9+10) Unicode 78.4ms ± 5% 76.3ms ± 3% -2.60% (p=0.009 n=10+10) GoTypes 1.09s ± 1% 1.08s ± 1% -0.73% (p=0.027 n=10+8) Compiler 85.6ms ± 3% 84.6ms ± 4% ~ (p=0.143 n=10+10) SSA 7.23s ± 1% 7.25s ± 1% ~ (p=0.780 n=10+9) Flate 116ms ± 5% 115ms ± 6% ~ (p=0.912 n=10+10) GoParser 201ms ± 4% 195ms ± 1% ~ (p=0.089 n=10+10) Reflect 455ms ± 1% 458ms ± 2% ~ (p=0.050 n=9+9) Tar 155ms ± 2% 155ms ± 3% ~ (p=0.436 n=10+10) XML 202ms ± 2% 200ms ± 2% ~ (p=0.053 n=10+9) Change-Id: I33a7f383d79afba1a482cac6da0cf5b7de9c0ec4 Reviewed-on: https://go-review.googlesource.com/c/go/+/313514 Trust: Cherry Zhang <cherryyz@google.com> Reviewed-by: Than McIntosh <thanm@google.com>
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