Previously TryBot-tested with bucket bits = 4.
Also tested locally with bucket bits = 5.
This makes it much easier to change the size of map
buckets, and hopefully provides pointers to all the
code that in some way depends on details of map layout.
Change-Id: I9f6669d1eadd02f182d0bc3f959dc5f385fa1683
Reviewed-on: https://go-review.googlesource.com/c/go/+/462115
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Austin Clements <austin@google.com>
import (
"encoding/binary"
"fmt"
+ "internal/abi"
"os"
"sort"
"strings"
// we include only enough information to generate a correct GC
// program for it.
// Make sure this stays in sync with runtime/map.go.
+//
+// A "bucket" is a "struct" {
+// tophash [BUCKETSIZE]uint8
+// keys [BUCKETSIZE]keyType
+// elems [BUCKETSIZE]elemType
+// overflow *bucket
+// }
const (
- BUCKETSIZE = 8
- MAXKEYSIZE = 128
- MAXELEMSIZE = 128
+ BUCKETSIZE = abi.MapBucketCount
+ MAXKEYSIZE = abi.MapMaxKeyBytes
+ MAXELEMSIZE = abi.MapMaxElemBytes
)
func structfieldSize() int { return 3 * types.PtrSize } // Sizeof(runtime.structfield{})
"debug/macho",
"debug/pe",
"go/constant",
+ "internal/abi",
"internal/coverage",
"internal/buildcfg",
+ "internal/goarch",
"internal/goexperiment",
"internal/goroot",
"internal/goversion",
"cmd/link/internal/loader"
"cmd/link/internal/sym"
"fmt"
+ "internal/abi"
"internal/buildcfg"
"log"
"path"
// synthesizemaptypes is way too closely married to runtime/hashmap.c
const (
- MaxKeySize = 128
- MaxValSize = 128
- BucketSize = 8
+ MaxKeySize = abi.MapMaxKeyBytes
+ MaxValSize = abi.MapMaxElemBytes
+ BucketSize = abi.MapBucketCount
)
func (d *dwctxt) mkinternaltype(ctxt *Link, abbrev int, typename, keyname, valname string, f func(*dwarf.DWDie)) loader.Sym {
func (b *IntArgRegBitmap) Get(i int) bool {
return b[i/8]&(uint8(1)<<(i%8)) != 0
}
-
-// FuncPC* intrinsics.
-//
-// CAREFUL: In programs with plugins, FuncPC* can return different values
-// for the same function (because there are actually multiple copies of
-// the same function in the address space). To be safe, don't use the
-// results of this function in any == expression. It is only safe to
-// use the result as an address at which to start executing code.
-
-// FuncPCABI0 returns the entry PC of the function f, which must be a
-// direct reference of a function defined as ABI0. Otherwise it is a
-// compile-time error.
-//
-// Implemented as a compile intrinsic.
-func FuncPCABI0(f any) uintptr
-
-// FuncPCABIInternal returns the entry PC of the function f. If f is a
-// direct reference of a function, it must be defined as ABIInternal.
-// Otherwise it is a compile-time error. If f is not a direct reference
-// of a defined function, it assumes that f is a func value. Otherwise
-// the behavior is undefined.
-//
-// Implemented as a compile intrinsic.
-func FuncPCABIInternal(f any) uintptr
--- /dev/null
+// Copyright 2023 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.
+
+//go:build !compiler_bootstrap
+// +build !compiler_bootstrap
+
+package abi
+
+// The bootstrapping compiler doesn't understand "any" in the function signatures,
+// and also does not implement these intrinsics.
+
+// FuncPC* intrinsics.
+//
+// CAREFUL: In programs with plugins, FuncPC* can return different values
+// for the same function (because there are actually multiple copies of
+// the same function in the address space). To be safe, don't use the
+// results of this function in any == expression. It is only safe to
+// use the result as an address at which to start executing code.
+
+// FuncPCABI0 returns the entry PC of the function f, which must be a
+// direct reference of a function defined as ABI0. Otherwise it is a
+// compile-time error.
+//
+// Implemented as a compile intrinsic.
+func FuncPCABI0(f any) uintptr
+
+// FuncPCABIInternal returns the entry PC of the function f. If f is a
+// direct reference of a function, it must be defined as ABIInternal.
+// Otherwise it is a compile-time error. If f is not a direct reference
+// of a defined function, it assumes that f is a func value. Otherwise
+// the behavior is undefined.
+//
+// Implemented as a compile intrinsic.
+func FuncPCABIInternal(f any) uintptr
--- /dev/null
+// Copyright 2023 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 abi
+
+// Map constants common to several packages
+// runtime/runtime-gdb.py:MapTypePrinter contains its own copy
+const (
+ MapBucketCountBits = 3 // log2 of number of elements in a bucket.
+ MapBucketCount = 1 << MapBucketCountBits
+ MapMaxKeyBytes = 128 // Must fit in a uint8.
+ MapMaxElemBytes = 128 // Must fit in a uint8.
+)
"flag"
"fmt"
"go/token"
+ "internal/abi"
"internal/goarch"
"internal/testenv"
"io"
"unsafe"
)
+const bucketCount = abi.MapBucketCount
+
var sink any
func TestBool(t *testing.T) {
verifyGCBits(t, TypeOf(([][10000]Xscalar)(nil)), lit(1))
verifyGCBits(t, SliceOf(ArrayOf(10000, Tscalar)), lit(1))
- hdr := make([]byte, 8/goarch.PtrSize)
+ hdr := make([]byte, bucketCount/goarch.PtrSize)
verifyMapBucket := func(t *testing.T, k, e Type, m any, want []byte) {
verifyGCBits(t, MapBucketOf(k, e), want)
verifyMapBucket(t,
Tscalar, Tptr,
map[Xscalar]Xptr(nil),
- join(hdr, rep(8, lit(0)), rep(8, lit(1)), lit(1)))
+ join(hdr, rep(bucketCount, lit(0)), rep(bucketCount, lit(1)), lit(1)))
verifyMapBucket(t,
Tscalarptr, Tptr,
map[Xscalarptr]Xptr(nil),
- join(hdr, rep(8, lit(0, 1)), rep(8, lit(1)), lit(1)))
+ join(hdr, rep(bucketCount, lit(0, 1)), rep(bucketCount, lit(1)), lit(1)))
verifyMapBucket(t, Tint64, Tptr,
map[int64]Xptr(nil),
- join(hdr, rep(8, rep(8/goarch.PtrSize, lit(0))), rep(8, lit(1)), lit(1)))
+ join(hdr, rep(bucketCount, rep(8/goarch.PtrSize, lit(0))), rep(bucketCount, lit(1)), lit(1)))
verifyMapBucket(t,
Tscalar, Tscalar,
map[Xscalar]Xscalar(nil),
verifyMapBucket(t,
ArrayOf(2, Tscalarptr), ArrayOf(3, Tptrscalar),
map[[2]Xscalarptr][3]Xptrscalar(nil),
- join(hdr, rep(8*2, lit(0, 1)), rep(8*3, lit(1, 0)), lit(1)))
+ join(hdr, rep(bucketCount*2, lit(0, 1)), rep(bucketCount*3, lit(1, 0)), lit(1)))
verifyMapBucket(t,
ArrayOf(64/goarch.PtrSize, Tscalarptr), ArrayOf(64/goarch.PtrSize, Tptrscalar),
map[[64 / goarch.PtrSize]Xscalarptr][64 / goarch.PtrSize]Xptrscalar(nil),
- join(hdr, rep(8*64/goarch.PtrSize, lit(0, 1)), rep(8*64/goarch.PtrSize, lit(1, 0)), lit(1)))
+ join(hdr, rep(bucketCount*64/goarch.PtrSize, lit(0, 1)), rep(bucketCount*64/goarch.PtrSize, lit(1, 0)), lit(1)))
verifyMapBucket(t,
ArrayOf(64/goarch.PtrSize+1, Tscalarptr), ArrayOf(64/goarch.PtrSize, Tptrscalar),
map[[64/goarch.PtrSize + 1]Xscalarptr][64 / goarch.PtrSize]Xptrscalar(nil),
- join(hdr, rep(8, lit(1)), rep(8*64/goarch.PtrSize, lit(1, 0)), lit(1)))
+ join(hdr, rep(bucketCount, lit(1)), rep(bucketCount*64/goarch.PtrSize, lit(1, 0)), lit(1)))
verifyMapBucket(t,
ArrayOf(64/goarch.PtrSize, Tscalarptr), ArrayOf(64/goarch.PtrSize+1, Tptrscalar),
map[[64 / goarch.PtrSize]Xscalarptr][64/goarch.PtrSize + 1]Xptrscalar(nil),
- join(hdr, rep(8*64/goarch.PtrSize, lit(0, 1)), rep(8, lit(1)), lit(1)))
+ join(hdr, rep(bucketCount*64/goarch.PtrSize, lit(0, 1)), rep(bucketCount, lit(1)), lit(1)))
verifyMapBucket(t,
ArrayOf(64/goarch.PtrSize+1, Tscalarptr), ArrayOf(64/goarch.PtrSize+1, Tptrscalar),
map[[64/goarch.PtrSize + 1]Xscalarptr][64/goarch.PtrSize + 1]Xptrscalar(nil),
- join(hdr, rep(8, lit(1)), rep(8, lit(1)), lit(1)))
+ join(hdr, rep(bucketCount, lit(1)), rep(bucketCount, lit(1)), lit(1)))
}
func rep(n int, b []byte) []byte { return bytes.Repeat(b, n) }
package reflect
import (
+ "internal/abi"
"internal/goarch"
"strconv"
"sync"
// Currently, that's just size and the GC program. We also fill in string
// for possible debugging use.
const (
- bucketSize uintptr = 8
- maxKeySize uintptr = 128
- maxValSize uintptr = 128
+ bucketSize uintptr = abi.MapBucketCount
+ maxKeySize uintptr = abi.MapMaxKeyBytes
+ maxValSize uintptr = abi.MapMaxElemBytes
)
func bucketOf(ktyp, etyp *rtype) *rtype {
const (
// Maximum number of key/elem pairs a bucket can hold.
- bucketCntBits = 3
- bucketCnt = 1 << bucketCntBits
+ bucketCntBits = abi.MapBucketCountBits
+ bucketCnt = abi.MapBucketCount
- // Maximum average load of a bucket that triggers growth is 6.5.
+ // Maximum average load of a bucket that triggers growth is bucketCnt*13/16 (about 80% full)
+ // Because of minimum alignment rules, bucketCnt is known to be at least 8.
// Represent as loadFactorNum/loadFactorDen, to allow integer math.
- loadFactorNum = 13
loadFactorDen = 2
+ loadFactorNum = (bucketCnt * 13 / 16) * loadFactorDen
// Maximum key or elem size to keep inline (instead of mallocing per element).
// Must fit in a uint8.
// Fast versions cannot handle big elems - the cutoff size for
// fast versions in cmd/compile/internal/gc/walk.go must be at most this elem.
- maxKeySize = 128
- maxElemSize = 128
+ maxKeySize = abi.MapMaxKeyBytes
+ maxElemSize = abi.MapMaxElemBytes
// data offset should be the size of the bmap struct, but needs to be
// aligned correctly. For amd64p32 this means 64-bit alignment
import (
"fmt"
+ "internal/abi"
"internal/goarch"
"math"
"reflect"
}
func TestMapIterOrder(t *testing.T) {
- for _, n := range [...]int{3, 7, 9, 15} {
+ sizes := []int{3, 7, 9, 15}
+ if abi.MapBucketCountBits >= 5 {
+ // it gets flaky (often only one iteration order) at size 3 when abi.MapBucketCountBits >=5.
+ t.Fatalf("This test becomes flaky if abi.MapBucketCountBits(=%d) is 5 or larger", abi.MapBucketCountBits)
+ }
+ for _, n := range sizes {
for i := 0; i < 1000; i++ {
// Make m be {0: true, 1: true, ..., n-1: true}.
m := make(map[int]bool)
}
}
+const bs = abi.MapBucketCount
+
+// belowOverflow should be a pretty-full pair of buckets;
+// atOverflow is 1/8 bs larger = 13/8 buckets or two buckets
+// that are 13/16 full each, which is the overflow boundary.
+// Adding one to that should ensure overflow to the next higher size.
+const (
+ belowOverflow = bs * 3 / 2 // 1.5 bs = 2 buckets @ 75%
+ atOverflow = belowOverflow + bs/8 // 2 buckets at 13/16 fill.
+)
+
var mapBucketTests = [...]struct {
n int // n is the number of map elements
noescape int // number of expected buckets for non-escaping map
{-1, 1, 1},
{0, 1, 1},
{1, 1, 1},
- {8, 1, 1},
- {9, 2, 2},
- {13, 2, 2},
- {14, 4, 4},
- {26, 4, 4},
+ {bs, 1, 1},
+ {bs + 1, 2, 2},
+ {belowOverflow, 2, 2}, // 1.5 bs = 2 buckets @ 75%
+ {atOverflow + 1, 4, 4}, // 13/8 bs + 1 == overflow to 4
+
+ {2 * belowOverflow, 4, 4}, // 3 bs = 4 buckets @75%
+ {2*atOverflow + 1, 8, 8}, // 13/4 bs + 1 = overflow to 8
+
+ {4 * belowOverflow, 8, 8}, // 6 bs = 8 buckets @ 75%
+ {4*atOverflow + 1, 16, 16}, // 13/2 bs + 1 = overflow to 16
}
func TestMapBuckets(t *testing.T) {
return str(self.val.type)
def children(self):
+ MapBucketCount = 8 # see internal/abi.go:MapBucketCount
B = self.val['B']
buckets = self.val['buckets']
oldbuckets = self.val['oldbuckets']
bp = oldbp
while bp:
b = bp.dereference()
- for i in xrange(8):
+ for i in xrange(MapBucketCount):
if b['tophash'][i] != 0:
k = b['keys'][i]
v = b['values'][i]
"bytes"
"flag"
"fmt"
+ "internal/abi"
"internal/testenv"
"os"
"os/exec"
// TODO(mundaym): check for unknown frames (e.g. "??").
}
-const helloSource = `
+// NOTE: the maps below are allocated larger than abi.MapBucketCount
+// to ensure that they are not "optimized out".
+
+var helloSource = `
import "fmt"
import "runtime"
var gslice []string
func main() {
- mapvar := make(map[string]string, 13)
- slicemap := make(map[string][]string,11)
+ mapvar := make(map[string]string, ` + strconv.FormatInt(abi.MapBucketCount+9, 10) + `)
+ slicemap := make(map[string][]string,` + strconv.FormatInt(abi.MapBucketCount+3, 10) + `)
chanint := make(chan int, 10)
chanstr := make(chan string, 10)
chanint <- 99
}
func MapLiteralSizing(x int) (map[int]int, map[int]int) {
- // amd64:"MOVL\t[$]10,"
+ // This is tested for internal/abi/maps.go:MapBucketCountBits={3,4,5}
+ // amd64:"MOVL\t[$]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,
+ 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[$]10,"
+ // amd64:"MOVL\t[$]33,"
n := map[int]int{
- 0: x,
- 1: x,
- 2: x,
- 3: x,
- 4: x,
- 5: x,
- 6: x,
- 7: x,
- 8: x,
- 9: x,
+ 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
}