Commit graph

4 commits

Author SHA1 Message Date
Matthew Dempsky 6eede325ab cmd/compile: fix detection of duplicate cases for integer ranges
Previously, the check to make sure we only considered constant cases
for duplicates was skipping past integer ranges, because those use
n.List instead of n.Left. Thanks to Emmanuel Odeke for investigating
and helping to identify the root cause.

Fixes #17517.

Change-Id: I46fcda8ed9c346ff3a9647d50b83f1555587b740
Reviewed-on: https://go-review.googlesource.com/31716
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: Robert Griesemer <gri@golang.org>
2016-10-21 22:55:28 +00:00
Josh Bleecher Snyder e26499153e cmd/compile: use a map to track const switch cases
This is simpler than the sorting technique.
It also allows us to simplify or eliminate
some of the sorting decisions.

Most important, sorting will not work when case clauses
represent ranges of integers: There is no correct
sort order that allows overlap detection by comparing
neighbors. Using a map allows of a cheap, simple
approach to ranges, namely to insert every int
in the map. The equivalent approach for sorting
means juggling temporary Nodes for every int,
which is a lot more expensive.

Change-Id: I84df3cb805992a1b04d14e0e4b2334f943e0ce05
Reviewed-on: https://go-review.googlesource.com/26766
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2016-08-23 05:28:33 +00:00
Josh Bleecher Snyder bd2838be77 cmd/compile: use a map to detect duplicate type switch cases
This is a bit simpler than playing sorting games,
and it is clearer that it generates errors
in the correct (source) order.

It also allows us to simplify sorting.

It also prevents quadratic error messages for
(pathological) inputs with many duplicate type cases.

While we’re here, refactoring deduping into separate functions.

Negligible compilebench impact.

Fixes #15912.

Change-Id: I6cc19edd38875389a70ccbdbdf0d9b7d5ac5946f
Reviewed-on: https://go-review.googlesource.com/26762
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2016-08-23 05:17:05 +00:00
Josh Bleecher Snyder 8003e79154 test: add more switch error handling tests
Some of these errors are reported in the wrong places.
That’s issue #15911 and #15912.

Change-Id: Ia09d7f89be4d15f05217a542a61b6ac08090dd87
Reviewed-on: https://go-review.googlesource.com/23588
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-05-31 22:29:36 +00:00