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Matthew Dempsky fd43831f44 [dev.regabi] cmd/compile: reimplement capture analysis
Currently we rely on the type-checker to do some basic data-flow
analysis to help decide whether function literals should capture
variables by value or reference. However, this analysis isn't done by
go/types, and escape analysis already has a better framework for doing
this more precisely.

This CL extends escape analysis to recalculate the same "byval" as
CaptureVars and check that it matches. A future CL will remove
CaptureVars in favor of escape analysis's calculation.

Notably, escape analysis happens after deadcode removes obviously
unreachable code, so it sees the AST without any unreachable
assignments. (Also without unreachable addrtakens, but
ComputeAddrtaken already happens after deadcode too.) There are two
test cases where a variable is only reassigned on certain CPUs. This
CL changes them to reassign the variables unconditionally (as no-op
reassignments that avoid triggering cmd/vet's self-assignment check),
at least until we remove CaptureVars.

Passes toolstash -cmp.

Change-Id: I7162619739fedaf861b478fb8d506f96a6ac21f3
Reviewed-on: https://go-review.googlesource.com/c/go/+/281535
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
2021-01-05 21:11:38 +00:00
.github .github: add link to questions in ISSUE_TEMPLATE 2020-01-06 17:05:31 +00:00
api api/go1.16: remove crypto/tls APIs that are moved to Go 1.17 2020-12-17 20:25:45 +00:00
doc doc: fix a typo in contribute.html 2020-12-23 17:01:35 +00:00
lib/time lib/time, time/tzdata: update tzdata to 2020e 2020-12-23 17:29:16 +00:00
misc cmd/compile, runtime: use __msan_memmove for moving data, split msanread to fields 2020-12-03 15:40:11 +00:00
src [dev.regabi] cmd/compile: reimplement capture analysis 2021-01-05 21:11:38 +00:00
test [dev.regabi] cmd/compile: reimplement capture analysis 2021-01-05 21:11:38 +00:00
.gitattributes all: treat all files as binary, but check in .bat with CRLF 2020-06-08 15:31:43 +00:00
.gitignore .gitignore: ignore src/cmd/dist/dist 2017-10-28 21:55:49 +00:00
AUTHORS A+C: add Kush Patel (corporate CLA for Hootsuite Inc) 2020-07-08 00:10:44 +00:00
codereview.cfg [dev.regabi] codereview.cfg: add config for dev.regabi 2020-12-22 21:02:04 +00:00
CONTRIBUTING.md all: restore changes from faulty merge/revert 2018-02-12 20:13:59 +00:00
CONTRIBUTORS CONTRIBUTORS: update for the Go 1.15 release 2020-08-10 21:51:48 +00:00
favicon.ico website: recreate 16px and 32px favicon 2016-08-25 15:43:32 +00:00
LICENSE doc: revert copyright date to 2009 2016-06-01 22:40:04 +00:00
PATENTS LICENSE: separate, change PATENTS text 2010-12-06 16:31:59 -05:00
README.md README: linkify some paths 2018-06-06 18:07:01 +00:00
robots.txt godoc: serve robots.txt raw 2011-02-19 05:46:20 +11:00
SECURITY.md SECURITY.md: update go versions 2019-09-26 15:34:57 +00:00

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