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2 Commits

Author SHA1 Message Date
Matthew Dempsky
115e4c9c14 test: add test coverage for type-switch hash collisions
This CL expands the test for #29612 to check that type switches also
work correctly when type hashes collide.

Change-Id: Ia153743e6ea0736c1a33191acfe4d8ba890be527
Reviewed-on: https://go-review.googlesource.com/c/go/+/195782
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2019-09-16 22:14:49 +00:00
LE Manh Cuong
5fc55b3180 cmd/compile: use FmtLeft to generate symbol name for unexported interface methods
The bug in 29612 is that there are two similar-looking anonymous interface
types in two different packages, ./p1/ssa and ./p2/ssa:

v.(interface{ foo() }).foo()

These types should be treated differently because the unexported method
makes the types different (according to the spec).

But when generating the type descriptors for those two types, they
both have the name "interface { ssa.foo() }". They thus get the same
symbol, and the linker happily unifies them. It picks an arbitrary one
for the runtime to use, but that breaks conversions from concrete types
that have a foo method from the package which had its interface type
overwritten.

We need to encode the metadata symbol for unexported methods as package
path qualified (The same as we did in CL 27791 for struct fields).

So switching from FmtUnsigned to Fmtleft by default fixes the issue.
In case of generating namedata, FmtUnsigned is used.

The benchmark result ends up in no significant change of compiled binary
compare to the immediate parent.

Fixes #29612

Change-Id: I775aff91ae4a1bb16eb18a48d55e3b606f3f3352
Reviewed-on: https://go-review.googlesource.com/c/go/+/170157
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2019-04-01 17:27:06 +00:00