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cmd/compile: fix load of interface{}-typed OpIData in expand_calls

In certain cases, the declkared type of an OpIData is interface{}.
This was not expected (since interface{} is a pair, right?) and
thus caused a crash.  What is intended is that these be treated as
a byteptr, so do that instead (this is what happens in 1.15).

Fixes #42568.

Change-Id: Id7c9e5dc2cbb5d7c71c6748832491ea62b0b339f
Reviewed-on: https://go-review.googlesource.com/c/go/+/270057
Trust: David Chase <drchase@google.com>
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
This commit is contained in:
David Chase 2020-11-13 16:54:48 -05:00
parent 782cf560db
commit 92c732e901
3 changed files with 30 additions and 2 deletions

View File

@ -76,7 +76,7 @@ func storeByType(t *types.Type) obj.As {
return x86.AMOVQ return x86.AMOVQ
} }
} }
panic("bad store type") panic(fmt.Sprintf("bad store type %v", t))
} }
// moveByType returns the reg->reg move instruction of the given type. // moveByType returns the reg->reg move instruction of the given type.
@ -101,7 +101,7 @@ func moveByType(t *types.Type) obj.As {
case 16: case 16:
return x86.AMOVUPS // int128s are in SSE registers return x86.AMOVUPS // int128s are in SSE registers
default: default:
panic(fmt.Sprintf("bad int register width %d:%s", t.Size(), t)) panic(fmt.Sprintf("bad int register width %d:%v", t.Size(), t))
} }
} }
} }

View File

@ -196,6 +196,9 @@ func expandCalls(f *Func) {
} }
if leaf.Op == OpIData { if leaf.Op == OpIData {
leafType = removeTrivialWrapperTypes(leaf.Type) leafType = removeTrivialWrapperTypes(leaf.Type)
if leafType.IsEmptyInterface() {
leafType = typ.BytePtr
}
} }
aux := selector.Aux aux := selector.Aux
auxInt := selector.AuxInt + offset auxInt := selector.AuxInt + offset

View File

@ -0,0 +1,25 @@
// compile
// Copyright 2020 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Ensure that late expansion correctly handles an OpIData with type interface{}
package p
type S struct{}
func (S) M() {}
type I interface {
M()
}
func f(i I) {
o := i.(interface{})
if _, ok := i.(*S); ok {
o = nil
}
println(o)
}