mirror of
https://github.com/golang/go
synced 2024-11-15 01:00:29 -07:00
9dc3b8b722
First the insidious bug:
var n uintptr
for n := elemPtrs; n > 120; n -= 120 {
prog = append(prog, 120)
prog = append(prog, mask[:15]...)
mask = mask[15:]
}
prog = append(prog, byte(n))
prog = append(prog, mask[:(n+7)/8]...)
The := breaks this code, because the n after the loop is always 0!
We also do need to handle field padding correctly. In particular
the old padding code doesn't correctly handle fields that are not
a multiple of a pointer in size.
Fixes #30606.
Change-Id: Ifcab9494dc25c20116753c5d7e0145d6c2053ed8
Reviewed-on: https://go-review.googlesource.com/c/go/+/165860
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
52 lines
1.5 KiB
Go
52 lines
1.5 KiB
Go
// run
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// Copyright 2019 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package main
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import "reflect"
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func main() {}
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func typ(x interface{}) reflect.Type { return reflect.ValueOf(x).Type() }
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var byteType = typ((byte)(0))
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var ptrType = typ((*byte)(nil))
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// Arrays of pointers. There are two size thresholds.
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// Bit masks are chunked in groups of 120 pointers.
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// Array types with >16384 pointers have a GC program instead of a bitmask.
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var smallPtrType = reflect.ArrayOf(100, ptrType)
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var mediumPtrType = reflect.ArrayOf(1000, ptrType)
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var bigPtrType = reflect.ArrayOf(16385, ptrType)
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var x0 = reflect.New(reflect.StructOf([]reflect.StructField{
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{Name: "F1", Type: byteType},
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{Name: "F2", Type: bigPtrType},
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}))
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var x1 = reflect.New(reflect.StructOf([]reflect.StructField{
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{Name: "F1", Type: smallPtrType},
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{Name: "F2", Type: bigPtrType},
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}))
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var x2 = reflect.New(reflect.StructOf([]reflect.StructField{
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{Name: "F1", Type: mediumPtrType},
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{Name: "F2", Type: bigPtrType},
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}))
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var x3 = reflect.New(reflect.StructOf([]reflect.StructField{
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{Name: "F1", Type: ptrType},
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{Name: "F2", Type: byteType},
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{Name: "F3", Type: bigPtrType},
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}))
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var x4 = reflect.New(reflect.StructOf([]reflect.StructField{
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{Name: "F1", Type: ptrType},
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{Name: "F2", Type: smallPtrType},
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{Name: "F3", Type: bigPtrType},
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}))
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var x5 = reflect.New(reflect.StructOf([]reflect.StructField{
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{Name: "F1", Type: ptrType},
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{Name: "F2", Type: mediumPtrType},
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{Name: "F3", Type: bigPtrType},
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}))
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