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// Copyright 2022 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.
package compare
import (
"cmd/compile/internal/base"
"cmd/compile/internal/typecheck"
"cmd/compile/internal/types"
"cmd/internal/obj"
"cmd/internal/src"
"cmd/internal/sys"
"testing"
)
type typefn func() *types.Type
func init() {
// These are the few constants that need to be initialized in order to use
// the types package without using the typecheck package by calling
// typecheck.InitUniverse() (the normal way to initialize the types package).
types.PtrSize = 8
types.RegSize = 8
types.MaxWidth = 1 << 50
typecheck.InitUniverse()
base.Ctxt = &obj.Link{Arch: &obj.LinkArch{Arch: &sys.Arch{Alignment: 1, CanMergeLoads: true}}}
}
func TestEqStructCost(t *testing.T) {
newByteField := func(parent *types.Type, offset int64) *types.Field {
f := types.NewField(src.XPos{}, parent.Sym(), types.ByteType)
f.Offset = offset
return f
}
newArrayField := func(parent *types.Type, offset int64, len int64, kind types.Kind) *types.Field {
f := types.NewField(src.XPos{}, parent.Sym(), types.NewArray(types.Types[kind], len))
// Call Type.Size here to force the size calculation to be done. If not done here the size returned later is incorrect.
f.Type.Size()
f.Offset = offset
return f
}
newField := func(parent *types.Type, offset int64, kind types.Kind) *types.Field {
f := types.NewField(src.XPos{}, parent.Sym(), types.Types[kind])
f.Offset = offset
return f
}
tt := []struct {
name string
cost int64
nonMergeLoadCost int64
tfn typefn
}{
{"struct without fields", 0, 0,
func() *types.Type {
return types.NewStruct([]*types.Field{})
}},
{"struct with 1 byte field", 1, 1,
func() *types.Type {
parent := types.NewStruct([]*types.Field{})
fields := []*types.Field{
newByteField(parent, 0),
}
parent.SetFields(fields)
return parent
},
},
{"struct with 8 byte fields", 1, 8,
func() *types.Type {
parent := types.NewStruct([]*types.Field{})
fields := make([]*types.Field, 8)
for i := range fields {
fields[i] = newByteField(parent, int64(i))
}
parent.SetFields(fields)
return parent
},
},
{"struct with 16 byte fields", 2, 16,
func() *types.Type {
parent := types.NewStruct([]*types.Field{})
fields := make([]*types.Field, 16)
for i := range fields {
fields[i] = newByteField(parent, int64(i))
}
parent.SetFields(fields)
return parent
},
},
{"struct with 32 byte fields", 4, 32,
func() *types.Type {
parent := types.NewStruct([]*types.Field{})
fields := make([]*types.Field, 32)
for i := range fields {
fields[i] = newByteField(parent, int64(i))
}
parent.SetFields(fields)
return parent
},
},
{"struct with 2 int32 fields", 1, 2,
func() *types.Type {
parent := types.NewStruct([]*types.Field{})
fields := make([]*types.Field, 2)
for i := range fields {
fields[i] = newField(parent, int64(i*4), types.TINT32)
}
parent.SetFields(fields)
return parent
},
},
{"struct with 2 int32 fields and 1 int64", 2, 3,
func() *types.Type {
parent := types.NewStruct([]*types.Field{})
fields := make([]*types.Field, 3)
fields[0] = newField(parent, int64(0), types.TINT32)
fields[1] = newField(parent, int64(4), types.TINT32)
fields[2] = newField(parent, int64(8), types.TINT64)
parent.SetFields(fields)
return parent
},
},
{"struct with 1 int field and 1 string", 3, 3,
func() *types.Type {
parent := types.NewStruct([]*types.Field{})
fields := make([]*types.Field, 2)
fields[0] = newField(parent, int64(0), types.TINT64)
fields[1] = newField(parent, int64(8), types.TSTRING)
parent.SetFields(fields)
return parent
},
},
{"struct with 2 strings", 4, 4,
func() *types.Type {
parent := types.NewStruct([]*types.Field{})
fields := make([]*types.Field, 2)
fields[0] = newField(parent, int64(0), types.TSTRING)
fields[1] = newField(parent, int64(8), types.TSTRING)
parent.SetFields(fields)
return parent
},
},
{"struct with 1 large byte array field", 26, 101,
func() *types.Type {
parent := types.NewStruct([]*types.Field{})
fields := []*types.Field{
newArrayField(parent, 0, 101, types.TUINT16),
}
parent.SetFields(fields)
return parent
},
},
{"struct with string array field", 4, 4,
func() *types.Type {
parent := types.NewStruct([]*types.Field{})
fields := []*types.Field{
newArrayField(parent, 0, 2, types.TSTRING),
}
parent.SetFields(fields)
return parent
},
},
}
for _, tc := range tt {
t.Run(tc.name, func(t *testing.T) {
want := tc.cost
base.Ctxt.Arch.CanMergeLoads = true
actual := EqStructCost(tc.tfn())
if actual != want {
t.Errorf("CanMergeLoads=true EqStructCost(%v) = %d, want %d", tc.tfn, actual, want)
}
base.Ctxt.Arch.CanMergeLoads = false
want = tc.nonMergeLoadCost
actual = EqStructCost(tc.tfn())
if actual != want {
t.Errorf("CanMergeLoads=false EqStructCost(%v) = %d, want %d", tc.tfn, actual, want)
}
})
}
}