tree 25c62b6baae248ec75c26f0408712fbd49fdc3aa
parent 4ea6123e078542fd57c72b5f527b5705b39c33f4
author Robert Findley <rfindley@google.com> 1634742173 -0400
committer Robert Findley <rfindley@google.com> 1634755731 +0000

go/internal/gcimporter: avoid setting unnecessary lines in fakeFileSet

As discussed in golang/go#46586, the gcimporter spends large portion of
time just validating fake lines.

Fix this by only setting the lines we need. Benchcmd results for
TestImportStdLib:

name              old time/op         new time/op         delta
TestImportStdLib          1.11s ±40%          0.57s ±58%  -48.17%  (p=0.000 n=18+18)

name              old user-time/op    new user-time/op    delta
TestImportStdLib          1.24s ±46%          0.71s ±61%  -42.84%  (p=0.000 n=18+18)

name              old sys-time/op     new sys-time/op     delta
TestImportStdLib          249ms ±64%          139ms ±47%  -44.19%  (p=0.000 n=19+18)

name              old peak-RSS-bytes  new peak-RSS-bytes  delta
TestImportStdLib         80.1MB ±24%         86.6MB ±13%   +8.06%  (p=0.001 n=20+20)

Fixes golang/go#46586

Change-Id: I5ef99ea9f242fc80d2d17750a8d9b28f7fc71245
Reviewed-on: https://go-review.googlesource.com/c/tools/+/357291
Trust: Robert Findley <rfindley@google.com>
Run-TryBot: Robert Findley <rfindley@google.com>
gopls-CI: kokoro <noreply+kokoro@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>