go/test/codegen/maps.go
Keith Randall 89c2f282dc cmd/compile: move []byte->string map key optimization to ssa
If we call slicebytetostring immediately (with no intervening writes)
before calling map access or delete functions with the resulting
string as the key, then we can just use the ptr/len of the
slicebytetostring argument as the key. This avoids an allocation.

Fixes #44898
Update #71132

There's old code in cmd/compile/internal/walk/order.go that handles
some of these cases.

1. m[string(b)]
2. s := string(b); m[s]
3. m[[2]string{string(b1),string(b2)}]

The old code handled cases 1&3. The new code handles cases 1&2.
We'll leave the old code around to keep 3 working, although it seems
not terribly common.

Case 2 happens particularly after inlining, so it is pretty common.

Change-Id: I8913226ca79d2c65f4e2bd69a38ac8c976a57e43
Reviewed-on: https://go-review.googlesource.com/c/go/+/640656
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2025-02-13 13:03:07 -08:00

224 lines
4.3 KiB
Go

// asmcheck
// Copyright 2018 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 codegen
// This file contains code generation tests related to the handling of
// map types.
// ------------------- //
// Access Const //
// ------------------- //
// Direct use of constants in fast map access calls (Issue #19015).
func AccessInt1(m map[int]int) int {
// amd64:"MOV[LQ]\t[$]5"
return m[5]
}
func AccessInt2(m map[int]int) bool {
// amd64:"MOV[LQ]\t[$]5"
_, ok := m[5]
return ok
}
func AccessString1(m map[string]int) int {
// amd64:`.*"abc"`
return m["abc"]
}
func AccessString2(m map[string]int) bool {
// amd64:`.*"abc"`
_, ok := m["abc"]
return ok
}
// ------------------- //
// String Conversion //
// ------------------- //
func LookupStringConversionSimple(m map[string]int, bytes []byte) int {
// amd64:-`.*runtime\.slicebytetostring\(`
return m[string(bytes)]
}
func LookupStringConversionStructLit(m map[struct{ string }]int, bytes []byte) int {
// amd64:-`.*runtime\.slicebytetostring\(`
return m[struct{ string }{string(bytes)}]
}
func LookupStringConversionArrayLit(m map[[2]string]int, bytes []byte) int {
// amd64:-`.*runtime\.slicebytetostring\(`
return m[[2]string{string(bytes), string(bytes)}]
}
func LookupStringConversionNestedLit(m map[[1]struct{ s [1]string }]int, bytes []byte) int {
// amd64:-`.*runtime\.slicebytetostring\(`
return m[[1]struct{ s [1]string }{struct{ s [1]string }{s: [1]string{string(bytes)}}}]
}
func LookupStringConversionKeyedArrayLit(m map[[2]string]int, bytes []byte) int {
// amd64:-`.*runtime\.slicebytetostring\(`
return m[[2]string{0: string(bytes)}]
}
func LookupStringConversion1(m map[string]int, bytes []byte) int {
// amd64:-`.*runtime\.slicebytetostring\(`
s := string(bytes)
return m[s]
}
func LookupStringConversion2(m *map[string]int, bytes []byte) int {
// amd64:-`.*runtime\.slicebytetostring\(`
s := string(bytes)
return (*m)[s]
}
func LookupStringConversion3(m map[string]int, bytes []byte) (int, bool) {
// amd64:-`.*runtime\.slicebytetostring\(`
s := string(bytes)
r, ok := m[s]
return r, ok
}
func DeleteStringConversion(m map[string]int, bytes []byte) {
// amd64:-`.*runtime\.slicebytetostring\(`
s := string(bytes)
delete(m, s)
}
// ------------------- //
// Map Clear //
// ------------------- //
// Optimization of map clear idiom (Issue #20138).
func MapClearReflexive(m map[int]int) {
// amd64:`.*runtime\.mapclear`
// amd64:-`.*runtime\.(mapiterinit|mapIterStart)`
for k := range m {
delete(m, k)
}
}
func MapClearIndirect(m map[int]int) {
s := struct{ m map[int]int }{m: m}
// amd64:`.*runtime\.mapclear`
// amd64:-`.*runtime\.(mapiterinit|mapIterStart)`
for k := range s.m {
delete(s.m, k)
}
}
func MapClearPointer(m map[*byte]int) {
// amd64:`.*runtime\.mapclear`
// amd64:-`.*runtime\.(mapiterinit|mapIterStart)`
for k := range m {
delete(m, k)
}
}
func MapClearNotReflexive(m map[float64]int) {
// amd64:`.*runtime\.(mapiterinit|mapIterStart)`
// amd64:-`.*runtime\.mapclear`
for k := range m {
delete(m, k)
}
}
func MapClearInterface(m map[interface{}]int) {
// amd64:`.*runtime\.(mapiterinit|mapIterStart)`
// amd64:-`.*runtime\.mapclear`
for k := range m {
delete(m, k)
}
}
func MapClearSideEffect(m map[int]int) int {
k := 0
// amd64:`.*runtime\.(mapiterinit|mapIterStart)`
// amd64:-`.*runtime\.mapclear`
for k = range m {
delete(m, k)
}
return k
}
func MapLiteralSizing(x int) (map[int]int, map[int]int) {
// This is tested for internal/abi/maps.go:MapBucketCountBits={3,4,5}
// amd64:"MOVL\t[$]33,"
m := map[int]int{
0: 0,
1: 1,
2: 2,
3: 3,
4: 4,
5: 5,
6: 6,
7: 7,
8: 8,
9: 9,
10: 10,
11: 11,
12: 12,
13: 13,
14: 14,
15: 15,
16: 16,
17: 17,
18: 18,
19: 19,
20: 20,
21: 21,
22: 22,
23: 23,
24: 24,
25: 25,
26: 26,
27: 27,
28: 28,
29: 29,
30: 30,
31: 32,
32: 32,
}
// amd64:"MOVL\t[$]33,"
n := map[int]int{
0: 0,
1: 1,
2: 2,
3: 3,
4: 4,
5: 5,
6: 6,
7: 7,
8: 8,
9: 9,
10: 10,
11: 11,
12: 12,
13: 13,
14: 14,
15: 15,
16: 16,
17: 17,
18: 18,
19: 19,
20: 20,
21: 21,
22: 22,
23: 23,
24: 24,
25: 25,
26: 26,
27: 27,
28: 28,
29: 29,
30: 30,
31: 32,
32: 32,
}
return m, n
}