141 lines
3.4 KiB
Go
141 lines
3.4 KiB
Go
// Copyright (c) 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 field
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import (
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"testing"
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"testing/quick"
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)
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func checkAliasingOneArg(f func(v, x *Element) *Element) func(v, x Element) bool {
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return func(v, x Element) bool {
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x1, v1 := x, x
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// Calculate a reference f(x) without aliasing.
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if out := f(&v, &x); out != &v && isInBounds(out) {
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return false
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}
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// Test aliasing the argument and the receiver.
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if out := f(&v1, &v1); out != &v1 || v1 != v {
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return false
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}
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// Ensure the arguments was not modified.
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return x == x1
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}
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}
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func checkAliasingTwoArgs(f func(v, x, y *Element) *Element) func(v, x, y Element) bool {
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return func(v, x, y Element) bool {
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x1, y1, v1 := x, y, Element{}
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// Calculate a reference f(x, y) without aliasing.
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if out := f(&v, &x, &y); out != &v && isInBounds(out) {
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return false
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}
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// Test aliasing the first argument and the receiver.
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v1 = x
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if out := f(&v1, &v1, &y); out != &v1 || v1 != v {
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return false
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}
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// Test aliasing the second argument and the receiver.
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v1 = y
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if out := f(&v1, &x, &v1); out != &v1 || v1 != v {
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return false
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}
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// Calculate a reference f(x, x) without aliasing.
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if out := f(&v, &x, &x); out != &v {
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return false
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}
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// Test aliasing the first argument and the receiver.
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v1 = x
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if out := f(&v1, &v1, &x); out != &v1 || v1 != v {
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return false
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}
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// Test aliasing the second argument and the receiver.
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v1 = x
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if out := f(&v1, &x, &v1); out != &v1 || v1 != v {
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return false
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}
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// Test aliasing both arguments and the receiver.
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v1 = x
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if out := f(&v1, &v1, &v1); out != &v1 || v1 != v {
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return false
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}
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// Ensure the arguments were not modified.
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return x == x1 && y == y1
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}
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}
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// TestAliasing checks that receivers and arguments can alias each other without
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// leading to incorrect results. That is, it ensures that it's safe to write
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//
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// v.Invert(v)
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//
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// or
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//
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// v.Add(v, v)
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//
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// without any of the inputs getting clobbered by the output being written.
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func TestAliasing(t *testing.T) {
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type target struct {
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name string
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oneArgF func(v, x *Element) *Element
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twoArgsF func(v, x, y *Element) *Element
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}
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for _, tt := range []target{
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{name: "Absolute", oneArgF: (*Element).Absolute},
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{name: "Invert", oneArgF: (*Element).Invert},
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{name: "Negate", oneArgF: (*Element).Negate},
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{name: "Set", oneArgF: (*Element).Set},
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{name: "Square", oneArgF: (*Element).Square},
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{name: "Pow22523", oneArgF: (*Element).Pow22523},
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{
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name: "Mult32",
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oneArgF: func(v, x *Element) *Element {
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return v.Mult32(x, 0xffffffff)
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},
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},
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{name: "Multiply", twoArgsF: (*Element).Multiply},
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{name: "Add", twoArgsF: (*Element).Add},
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{name: "Subtract", twoArgsF: (*Element).Subtract},
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{
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name: "SqrtRatio",
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twoArgsF: func(v, x, y *Element) *Element {
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r, _ := v.SqrtRatio(x, y)
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return r
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},
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},
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{
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name: "Select0",
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twoArgsF: func(v, x, y *Element) *Element {
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return v.Select(x, y, 0)
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},
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},
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{
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name: "Select1",
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twoArgsF: func(v, x, y *Element) *Element {
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return v.Select(x, y, 1)
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},
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},
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} {
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var err error
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switch {
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case tt.oneArgF != nil:
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err = quick.Check(checkAliasingOneArg(tt.oneArgF), quickCheckConfig(256))
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case tt.twoArgsF != nil:
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err = quick.Check(checkAliasingTwoArgs(tt.twoArgsF), quickCheckConfig(256))
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}
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if err != nil {
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t.Errorf("%v: %v", tt.name, err)
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}
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}
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}
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