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https://github.com/autc04/Retro68.git
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1311 lines
40 KiB
Go
1311 lines
40 KiB
Go
// Copyright 2014 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 runtime
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// This file contains the implementation of Go's map type.
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//
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// A map is just a hash table. The data is arranged
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// into an array of buckets. Each bucket contains up to
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// 8 key/value pairs. The low-order bits of the hash are
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// used to select a bucket. Each bucket contains a few
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// high-order bits of each hash to distinguish the entries
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// within a single bucket.
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//
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// If more than 8 keys hash to a bucket, we chain on
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// extra buckets.
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//
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// When the hashtable grows, we allocate a new array
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// of buckets twice as big. Buckets are incrementally
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// copied from the old bucket array to the new bucket array.
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//
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// Map iterators walk through the array of buckets and
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// return the keys in walk order (bucket #, then overflow
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// chain order, then bucket index). To maintain iteration
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// semantics, we never move keys within their bucket (if
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// we did, keys might be returned 0 or 2 times). When
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// growing the table, iterators remain iterating through the
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// old table and must check the new table if the bucket
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// they are iterating through has been moved ("evacuated")
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// to the new table.
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// Picking loadFactor: too large and we have lots of overflow
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// buckets, too small and we waste a lot of space. I wrote
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// a simple program to check some stats for different loads:
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// (64-bit, 8 byte keys and values)
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// loadFactor %overflow bytes/entry hitprobe missprobe
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// 4.00 2.13 20.77 3.00 4.00
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// 4.50 4.05 17.30 3.25 4.50
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// 5.00 6.85 14.77 3.50 5.00
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// 5.50 10.55 12.94 3.75 5.50
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// 6.00 15.27 11.67 4.00 6.00
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// 6.50 20.90 10.79 4.25 6.50
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// 7.00 27.14 10.15 4.50 7.00
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// 7.50 34.03 9.73 4.75 7.50
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// 8.00 41.10 9.40 5.00 8.00
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//
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// %overflow = percentage of buckets which have an overflow bucket
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// bytes/entry = overhead bytes used per key/value pair
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// hitprobe = # of entries to check when looking up a present key
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// missprobe = # of entries to check when looking up an absent key
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//
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// Keep in mind this data is for maximally loaded tables, i.e. just
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// before the table grows. Typical tables will be somewhat less loaded.
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import (
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"runtime/internal/atomic"
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"runtime/internal/sys"
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"unsafe"
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)
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// For gccgo, use go:linkname to rename compiler-called functions to
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// themselves, so that the compiler will export them.
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//
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//go:linkname makemap runtime.makemap
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//go:linkname makemap64 runtime.makemap64
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//go:linkname makemap_small runtime.makemap_small
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//go:linkname mapaccess1 runtime.mapaccess1
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//go:linkname mapaccess2 runtime.mapaccess2
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//go:linkname mapaccess1_fat runtime.mapaccess1_fat
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//go:linkname mapaccess2_fat runtime.mapaccess2_fat
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//go:linkname mapassign runtime.mapassign
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//go:linkname mapdelete runtime.mapdelete
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//go:linkname mapiterinit runtime.mapiterinit
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//go:linkname mapiternext runtime.mapiternext
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const (
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// Maximum number of key/value pairs a bucket can hold.
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bucketCntBits = 3
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bucketCnt = 1 << bucketCntBits
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// Maximum average load of a bucket that triggers growth is 6.5.
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// Represent as loadFactorNum/loadFactDen, to allow integer math.
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loadFactorNum = 13
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loadFactorDen = 2
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// Maximum key or value size to keep inline (instead of mallocing per element).
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// Must fit in a uint8.
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// Fast versions cannot handle big values - the cutoff size for
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// fast versions in ../../cmd/internal/gc/walk.go must be at most this value.
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maxKeySize = 128
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maxValueSize = 128
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// data offset should be the size of the bmap struct, but needs to be
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// aligned correctly. For amd64p32 this means 64-bit alignment
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// even though pointers are 32 bit.
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dataOffset = unsafe.Offsetof(struct {
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b bmap
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v int64
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}{}.v)
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// Possible tophash values. We reserve a few possibilities for special marks.
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// Each bucket (including its overflow buckets, if any) will have either all or none of its
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// entries in the evacuated* states (except during the evacuate() method, which only happens
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// during map writes and thus no one else can observe the map during that time).
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empty = 0 // cell is empty
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evacuatedEmpty = 1 // cell is empty, bucket is evacuated.
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evacuatedX = 2 // key/value is valid. Entry has been evacuated to first half of larger table.
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evacuatedY = 3 // same as above, but evacuated to second half of larger table.
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minTopHash = 4 // minimum tophash for a normal filled cell.
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// flags
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iterator = 1 // there may be an iterator using buckets
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oldIterator = 2 // there may be an iterator using oldbuckets
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hashWriting = 4 // a goroutine is writing to the map
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sameSizeGrow = 8 // the current map growth is to a new map of the same size
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// sentinel bucket ID for iterator checks
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noCheck = 1<<(8*sys.PtrSize) - 1
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)
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// A header for a Go map.
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type hmap struct {
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// Note: the format of the Hmap is encoded in ../../cmd/internal/gc/reflect.go and
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// ../reflect/type.go. Don't change this structure without also changing that code!
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count int // # live cells == size of map. Must be first (used by len() builtin)
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flags uint8
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B uint8 // log_2 of # of buckets (can hold up to loadFactor * 2^B items)
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noverflow uint16 // approximate number of overflow buckets; see incrnoverflow for details
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hash0 uint32 // hash seed
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buckets unsafe.Pointer // array of 2^B Buckets. may be nil if count==0.
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oldbuckets unsafe.Pointer // previous bucket array of half the size, non-nil only when growing
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nevacuate uintptr // progress counter for evacuation (buckets less than this have been evacuated)
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extra *mapextra // optional fields
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}
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// mapextra holds fields that are not present on all maps.
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type mapextra struct {
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// If both key and value do not contain pointers and are inline, then we mark bucket
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// type as containing no pointers. This avoids scanning such maps.
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// However, bmap.overflow is a pointer. In order to keep overflow buckets
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// alive, we store pointers to all overflow buckets in hmap.overflow and h.map.oldoverflow.
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// overflow and oldoverflow are only used if key and value do not contain pointers.
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// overflow contains overflow buckets for hmap.buckets.
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// oldoverflow contains overflow buckets for hmap.oldbuckets.
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// The indirection allows to store a pointer to the slice in hiter.
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overflow *[]*bmap
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oldoverflow *[]*bmap
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// nextOverflow holds a pointer to a free overflow bucket.
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nextOverflow *bmap
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}
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// A bucket for a Go map.
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type bmap struct {
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// tophash generally contains the top byte of the hash value
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// for each key in this bucket. If tophash[0] < minTopHash,
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// tophash[0] is a bucket evacuation state instead.
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tophash [bucketCnt]uint8
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// Followed by bucketCnt keys and then bucketCnt values.
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// NOTE: packing all the keys together and then all the values together makes the
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// code a bit more complicated than alternating key/value/key/value/... but it allows
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// us to eliminate padding which would be needed for, e.g., map[int64]int8.
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// Followed by an overflow pointer.
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}
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// A hash iteration structure.
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// If you modify hiter, also change cmd/internal/gc/reflect.go to indicate
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// the layout of this structure.
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type hiter struct {
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key unsafe.Pointer // Must be in first position. Write nil to indicate iteration end (see cmd/internal/gc/range.go).
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value unsafe.Pointer // Must be in second position (see cmd/internal/gc/range.go).
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t *maptype
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h *hmap
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buckets unsafe.Pointer // bucket ptr at hash_iter initialization time
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bptr *bmap // current bucket
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overflow *[]*bmap // keeps overflow buckets of hmap.buckets alive
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oldoverflow *[]*bmap // keeps overflow buckets of hmap.oldbuckets alive
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startBucket uintptr // bucket iteration started at
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offset uint8 // intra-bucket offset to start from during iteration (should be big enough to hold bucketCnt-1)
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wrapped bool // already wrapped around from end of bucket array to beginning
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B uint8
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i uint8
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bucket uintptr
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checkBucket uintptr
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}
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// bucketShift returns 1<<b, optimized for code generation.
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func bucketShift(b uint8) uintptr {
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if sys.GoarchAmd64|sys.GoarchAmd64p32|sys.Goarch386 != 0 {
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b &= sys.PtrSize*8 - 1 // help x86 archs remove shift overflow checks
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}
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return uintptr(1) << b
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}
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// bucketMask returns 1<<b - 1, optimized for code generation.
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func bucketMask(b uint8) uintptr {
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return bucketShift(b) - 1
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}
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// tophash calculates the tophash value for hash.
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func tophash(hash uintptr) uint8 {
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top := uint8(hash >> (sys.PtrSize*8 - 8))
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if top < minTopHash {
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top += minTopHash
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}
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return top
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}
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func evacuated(b *bmap) bool {
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h := b.tophash[0]
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return h > empty && h < minTopHash
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}
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func (b *bmap) overflow(t *maptype) *bmap {
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return *(**bmap)(add(unsafe.Pointer(b), uintptr(t.bucketsize)-sys.PtrSize))
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}
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func (b *bmap) setoverflow(t *maptype, ovf *bmap) {
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*(**bmap)(add(unsafe.Pointer(b), uintptr(t.bucketsize)-sys.PtrSize)) = ovf
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}
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func (b *bmap) keys() unsafe.Pointer {
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return add(unsafe.Pointer(b), dataOffset)
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}
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// incrnoverflow increments h.noverflow.
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// noverflow counts the number of overflow buckets.
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// This is used to trigger same-size map growth.
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// See also tooManyOverflowBuckets.
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// To keep hmap small, noverflow is a uint16.
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// When there are few buckets, noverflow is an exact count.
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// When there are many buckets, noverflow is an approximate count.
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func (h *hmap) incrnoverflow() {
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// We trigger same-size map growth if there are
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// as many overflow buckets as buckets.
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// We need to be able to count to 1<<h.B.
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if h.B < 16 {
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h.noverflow++
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return
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}
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// Increment with probability 1/(1<<(h.B-15)).
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// When we reach 1<<15 - 1, we will have approximately
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// as many overflow buckets as buckets.
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mask := uint32(1)<<(h.B-15) - 1
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// Example: if h.B == 18, then mask == 7,
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// and fastrand & 7 == 0 with probability 1/8.
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if fastrand()&mask == 0 {
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h.noverflow++
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}
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}
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func (h *hmap) newoverflow(t *maptype, b *bmap) *bmap {
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var ovf *bmap
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if h.extra != nil && h.extra.nextOverflow != nil {
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// We have preallocated overflow buckets available.
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// See makeBucketArray for more details.
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ovf = h.extra.nextOverflow
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if ovf.overflow(t) == nil {
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// We're not at the end of the preallocated overflow buckets. Bump the pointer.
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h.extra.nextOverflow = (*bmap)(add(unsafe.Pointer(ovf), uintptr(t.bucketsize)))
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} else {
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// This is the last preallocated overflow bucket.
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// Reset the overflow pointer on this bucket,
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// which was set to a non-nil sentinel value.
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ovf.setoverflow(t, nil)
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h.extra.nextOverflow = nil
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}
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} else {
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ovf = (*bmap)(newobject(t.bucket))
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}
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h.incrnoverflow()
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if t.bucket.kind&kindNoPointers != 0 {
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h.createOverflow()
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*h.extra.overflow = append(*h.extra.overflow, ovf)
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}
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b.setoverflow(t, ovf)
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return ovf
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}
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func (h *hmap) createOverflow() {
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if h.extra == nil {
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h.extra = new(mapextra)
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}
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if h.extra.overflow == nil {
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h.extra.overflow = new([]*bmap)
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}
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}
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func makemap64(t *maptype, hint int64, h *hmap) *hmap {
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if int64(int(hint)) != hint {
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hint = 0
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}
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return makemap(t, int(hint), h)
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}
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// makehmap_small implements Go map creation for make(map[k]v) and
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// make(map[k]v, hint) when hint is known to be at most bucketCnt
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// at compile time and the map needs to be allocated on the heap.
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func makemap_small() *hmap {
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h := new(hmap)
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h.hash0 = fastrand()
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return h
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}
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// makemap implements Go map creation for make(map[k]v, hint).
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// If the compiler has determined that the map or the first bucket
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// can be created on the stack, h and/or bucket may be non-nil.
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// If h != nil, the map can be created directly in h.
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// If h.buckets != nil, bucket pointed to can be used as the first bucket.
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func makemap(t *maptype, hint int, h *hmap) *hmap {
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// The size of hmap should be 48 bytes on 64 bit
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// and 28 bytes on 32 bit platforms.
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if sz := unsafe.Sizeof(hmap{}); sz != 8+5*sys.PtrSize {
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println("runtime: sizeof(hmap) =", sz, ", t.hmap.size =", t.hmap.size)
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throw("bad hmap size")
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}
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if hint < 0 || hint > int(maxSliceCap(t.bucket.size)) {
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hint = 0
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}
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// initialize Hmap
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if h == nil {
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h = (*hmap)(newobject(t.hmap))
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}
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h.hash0 = fastrand()
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// find size parameter which will hold the requested # of elements
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B := uint8(0)
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for overLoadFactor(hint, B) {
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B++
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}
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h.B = B
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// allocate initial hash table
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// if B == 0, the buckets field is allocated lazily later (in mapassign)
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// If hint is large zeroing this memory could take a while.
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if h.B != 0 {
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var nextOverflow *bmap
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h.buckets, nextOverflow = makeBucketArray(t, h.B)
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if nextOverflow != nil {
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h.extra = new(mapextra)
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h.extra.nextOverflow = nextOverflow
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}
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}
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return h
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}
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// mapaccess1 returns a pointer to h[key]. Never returns nil, instead
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// it will return a reference to the zero object for the value type if
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// the key is not in the map.
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// NOTE: The returned pointer may keep the whole map live, so don't
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// hold onto it for very long.
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func mapaccess1(t *maptype, h *hmap, key unsafe.Pointer) unsafe.Pointer {
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// Check preemption, since unlike gc we don't check on every call.
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if getg().preempt {
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checkPreempt()
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}
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if raceenabled && h != nil {
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callerpc := getcallerpc()
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pc := funcPC(mapaccess1)
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racereadpc(unsafe.Pointer(h), callerpc, pc)
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raceReadObjectPC(t.key, key, callerpc, pc)
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}
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if msanenabled && h != nil {
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msanread(key, t.key.size)
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}
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if h == nil || h.count == 0 {
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return unsafe.Pointer(&zeroVal[0])
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}
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if h.flags&hashWriting != 0 {
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throw("concurrent map read and map write")
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}
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hashfn := t.key.hashfn
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equalfn := t.key.equalfn
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hash := hashfn(key, uintptr(h.hash0))
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m := bucketMask(h.B)
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b := (*bmap)(add(h.buckets, (hash&m)*uintptr(t.bucketsize)))
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if c := h.oldbuckets; c != nil {
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if !h.sameSizeGrow() {
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// There used to be half as many buckets; mask down one more power of two.
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m >>= 1
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}
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oldb := (*bmap)(add(c, (hash&m)*uintptr(t.bucketsize)))
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if !evacuated(oldb) {
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b = oldb
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}
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}
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top := tophash(hash)
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for ; b != nil; b = b.overflow(t) {
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for i := uintptr(0); i < bucketCnt; i++ {
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if b.tophash[i] != top {
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continue
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}
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k := add(unsafe.Pointer(b), dataOffset+i*uintptr(t.keysize))
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if t.indirectkey {
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k = *((*unsafe.Pointer)(k))
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}
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if equalfn(key, k) {
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v := add(unsafe.Pointer(b), dataOffset+bucketCnt*uintptr(t.keysize)+i*uintptr(t.valuesize))
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if t.indirectvalue {
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v = *((*unsafe.Pointer)(v))
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}
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return v
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}
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}
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}
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return unsafe.Pointer(&zeroVal[0])
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}
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func mapaccess2(t *maptype, h *hmap, key unsafe.Pointer) (unsafe.Pointer, bool) {
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// Check preemption, since unlike gc we don't check on every call.
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if getg().preempt {
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checkPreempt()
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}
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if raceenabled && h != nil {
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callerpc := getcallerpc()
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pc := funcPC(mapaccess2)
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racereadpc(unsafe.Pointer(h), callerpc, pc)
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raceReadObjectPC(t.key, key, callerpc, pc)
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}
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if msanenabled && h != nil {
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msanread(key, t.key.size)
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}
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if h == nil || h.count == 0 {
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return unsafe.Pointer(&zeroVal[0]), false
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}
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if h.flags&hashWriting != 0 {
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throw("concurrent map read and map write")
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}
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hashfn := t.key.hashfn
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equalfn := t.key.equalfn
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hash := hashfn(key, uintptr(h.hash0))
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m := bucketMask(h.B)
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b := (*bmap)(unsafe.Pointer(uintptr(h.buckets) + (hash&m)*uintptr(t.bucketsize)))
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if c := h.oldbuckets; c != nil {
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if !h.sameSizeGrow() {
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// There used to be half as many buckets; mask down one more power of two.
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m >>= 1
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}
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oldb := (*bmap)(unsafe.Pointer(uintptr(c) + (hash&m)*uintptr(t.bucketsize)))
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if !evacuated(oldb) {
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b = oldb
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}
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}
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top := tophash(hash)
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for ; b != nil; b = b.overflow(t) {
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for i := uintptr(0); i < bucketCnt; i++ {
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if b.tophash[i] != top {
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continue
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}
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k := add(unsafe.Pointer(b), dataOffset+i*uintptr(t.keysize))
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if t.indirectkey {
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k = *((*unsafe.Pointer)(k))
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}
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if equalfn(key, k) {
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v := add(unsafe.Pointer(b), dataOffset+bucketCnt*uintptr(t.keysize)+i*uintptr(t.valuesize))
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if t.indirectvalue {
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v = *((*unsafe.Pointer)(v))
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}
|
|
return v, true
|
|
}
|
|
}
|
|
}
|
|
return unsafe.Pointer(&zeroVal[0]), false
|
|
}
|
|
|
|
// returns both key and value. Used by map iterator
|
|
func mapaccessK(t *maptype, h *hmap, key unsafe.Pointer) (unsafe.Pointer, unsafe.Pointer) {
|
|
// Check preemption, since unlike gc we don't check on every call.
|
|
if getg().preempt {
|
|
checkPreempt()
|
|
}
|
|
|
|
if h == nil || h.count == 0 {
|
|
return nil, nil
|
|
}
|
|
hashfn := t.key.hashfn
|
|
equalfn := t.key.equalfn
|
|
hash := hashfn(key, uintptr(h.hash0))
|
|
m := bucketMask(h.B)
|
|
b := (*bmap)(unsafe.Pointer(uintptr(h.buckets) + (hash&m)*uintptr(t.bucketsize)))
|
|
if c := h.oldbuckets; c != nil {
|
|
if !h.sameSizeGrow() {
|
|
// There used to be half as many buckets; mask down one more power of two.
|
|
m >>= 1
|
|
}
|
|
oldb := (*bmap)(unsafe.Pointer(uintptr(c) + (hash&m)*uintptr(t.bucketsize)))
|
|
if !evacuated(oldb) {
|
|
b = oldb
|
|
}
|
|
}
|
|
top := tophash(hash)
|
|
for ; b != nil; b = b.overflow(t) {
|
|
for i := uintptr(0); i < bucketCnt; i++ {
|
|
if b.tophash[i] != top {
|
|
continue
|
|
}
|
|
k := add(unsafe.Pointer(b), dataOffset+i*uintptr(t.keysize))
|
|
if t.indirectkey {
|
|
k = *((*unsafe.Pointer)(k))
|
|
}
|
|
if equalfn(key, k) {
|
|
v := add(unsafe.Pointer(b), dataOffset+bucketCnt*uintptr(t.keysize)+i*uintptr(t.valuesize))
|
|
if t.indirectvalue {
|
|
v = *((*unsafe.Pointer)(v))
|
|
}
|
|
return k, v
|
|
}
|
|
}
|
|
}
|
|
return nil, nil
|
|
}
|
|
|
|
func mapaccess1_fat(t *maptype, h *hmap, key, zero unsafe.Pointer) unsafe.Pointer {
|
|
v := mapaccess1(t, h, key)
|
|
if v == unsafe.Pointer(&zeroVal[0]) {
|
|
return zero
|
|
}
|
|
return v
|
|
}
|
|
|
|
func mapaccess2_fat(t *maptype, h *hmap, key, zero unsafe.Pointer) (unsafe.Pointer, bool) {
|
|
v := mapaccess1(t, h, key)
|
|
if v == unsafe.Pointer(&zeroVal[0]) {
|
|
return zero, false
|
|
}
|
|
return v, true
|
|
}
|
|
|
|
// Like mapaccess, but allocates a slot for the key if it is not present in the map.
|
|
func mapassign(t *maptype, h *hmap, key unsafe.Pointer) unsafe.Pointer {
|
|
// Check preemption, since unlike gc we don't check on every call.
|
|
if getg().preempt {
|
|
checkPreempt()
|
|
}
|
|
|
|
if h == nil {
|
|
panic(plainError("assignment to entry in nil map"))
|
|
}
|
|
if raceenabled {
|
|
callerpc := getcallerpc()
|
|
pc := funcPC(mapassign)
|
|
racewritepc(unsafe.Pointer(h), callerpc, pc)
|
|
raceReadObjectPC(t.key, key, callerpc, pc)
|
|
}
|
|
if msanenabled {
|
|
msanread(key, t.key.size)
|
|
}
|
|
if h.flags&hashWriting != 0 {
|
|
throw("concurrent map writes")
|
|
}
|
|
hashfn := t.key.hashfn
|
|
equalfn := t.key.equalfn
|
|
hash := hashfn(key, uintptr(h.hash0))
|
|
|
|
// Set hashWriting after calling alg.hash, since alg.hash may panic,
|
|
// in which case we have not actually done a write.
|
|
h.flags |= hashWriting
|
|
|
|
if h.buckets == nil {
|
|
h.buckets = newobject(t.bucket) // newarray(t.bucket, 1)
|
|
}
|
|
|
|
again:
|
|
bucket := hash & bucketMask(h.B)
|
|
if h.growing() {
|
|
growWork(t, h, bucket)
|
|
}
|
|
b := (*bmap)(unsafe.Pointer(uintptr(h.buckets) + bucket*uintptr(t.bucketsize)))
|
|
top := tophash(hash)
|
|
|
|
var inserti *uint8
|
|
var insertk unsafe.Pointer
|
|
var val unsafe.Pointer
|
|
for {
|
|
for i := uintptr(0); i < bucketCnt; i++ {
|
|
if b.tophash[i] != top {
|
|
if b.tophash[i] == empty && inserti == nil {
|
|
inserti = &b.tophash[i]
|
|
insertk = add(unsafe.Pointer(b), dataOffset+i*uintptr(t.keysize))
|
|
val = add(unsafe.Pointer(b), dataOffset+bucketCnt*uintptr(t.keysize)+i*uintptr(t.valuesize))
|
|
}
|
|
continue
|
|
}
|
|
k := add(unsafe.Pointer(b), dataOffset+i*uintptr(t.keysize))
|
|
if t.indirectkey {
|
|
k = *((*unsafe.Pointer)(k))
|
|
}
|
|
if !equalfn(key, k) {
|
|
continue
|
|
}
|
|
// already have a mapping for key. Update it.
|
|
if t.needkeyupdate {
|
|
typedmemmove(t.key, k, key)
|
|
}
|
|
val = add(unsafe.Pointer(b), dataOffset+bucketCnt*uintptr(t.keysize)+i*uintptr(t.valuesize))
|
|
goto done
|
|
}
|
|
ovf := b.overflow(t)
|
|
if ovf == nil {
|
|
break
|
|
}
|
|
b = ovf
|
|
}
|
|
|
|
// Did not find mapping for key. Allocate new cell & add entry.
|
|
|
|
// If we hit the max load factor or we have too many overflow buckets,
|
|
// and we're not already in the middle of growing, start growing.
|
|
if !h.growing() && (overLoadFactor(h.count+1, h.B) || tooManyOverflowBuckets(h.noverflow, h.B)) {
|
|
hashGrow(t, h)
|
|
goto again // Growing the table invalidates everything, so try again
|
|
}
|
|
|
|
if inserti == nil {
|
|
// all current buckets are full, allocate a new one.
|
|
newb := h.newoverflow(t, b)
|
|
inserti = &newb.tophash[0]
|
|
insertk = add(unsafe.Pointer(newb), dataOffset)
|
|
val = add(insertk, bucketCnt*uintptr(t.keysize))
|
|
}
|
|
|
|
// store new key/value at insert position
|
|
if t.indirectkey {
|
|
kmem := newobject(t.key)
|
|
*(*unsafe.Pointer)(insertk) = kmem
|
|
insertk = kmem
|
|
}
|
|
if t.indirectvalue {
|
|
vmem := newobject(t.elem)
|
|
*(*unsafe.Pointer)(val) = vmem
|
|
}
|
|
typedmemmove(t.key, insertk, key)
|
|
*inserti = top
|
|
h.count++
|
|
|
|
done:
|
|
if h.flags&hashWriting == 0 {
|
|
throw("concurrent map writes")
|
|
}
|
|
h.flags &^= hashWriting
|
|
if t.indirectvalue {
|
|
val = *((*unsafe.Pointer)(val))
|
|
}
|
|
return val
|
|
}
|
|
|
|
func mapdelete(t *maptype, h *hmap, key unsafe.Pointer) {
|
|
if raceenabled && h != nil {
|
|
callerpc := getcallerpc()
|
|
pc := funcPC(mapdelete)
|
|
racewritepc(unsafe.Pointer(h), callerpc, pc)
|
|
raceReadObjectPC(t.key, key, callerpc, pc)
|
|
}
|
|
if msanenabled && h != nil {
|
|
msanread(key, t.key.size)
|
|
}
|
|
if h == nil || h.count == 0 {
|
|
return
|
|
}
|
|
if h.flags&hashWriting != 0 {
|
|
throw("concurrent map writes")
|
|
}
|
|
|
|
hashfn := t.key.hashfn
|
|
equalfn := t.key.equalfn
|
|
hash := hashfn(key, uintptr(h.hash0))
|
|
|
|
// Set hashWriting after calling alg.hash, since alg.hash may panic,
|
|
// in which case we have not actually done a write (delete).
|
|
h.flags |= hashWriting
|
|
|
|
bucket := hash & bucketMask(h.B)
|
|
if h.growing() {
|
|
growWork(t, h, bucket)
|
|
}
|
|
b := (*bmap)(add(h.buckets, bucket*uintptr(t.bucketsize)))
|
|
top := tophash(hash)
|
|
search:
|
|
for ; b != nil; b = b.overflow(t) {
|
|
for i := uintptr(0); i < bucketCnt; i++ {
|
|
if b.tophash[i] != top {
|
|
continue
|
|
}
|
|
k := add(unsafe.Pointer(b), dataOffset+i*uintptr(t.keysize))
|
|
k2 := k
|
|
if t.indirectkey {
|
|
k2 = *((*unsafe.Pointer)(k2))
|
|
}
|
|
if !equalfn(key, k2) {
|
|
continue
|
|
}
|
|
// Only clear key if there are pointers in it.
|
|
if t.indirectkey {
|
|
*(*unsafe.Pointer)(k) = nil
|
|
} else if t.key.kind&kindNoPointers == 0 {
|
|
memclrHasPointers(k, t.key.size)
|
|
}
|
|
// Only clear value if there are pointers in it.
|
|
if t.indirectvalue || t.elem.kind&kindNoPointers == 0 {
|
|
v := add(unsafe.Pointer(b), dataOffset+bucketCnt*uintptr(t.keysize)+i*uintptr(t.valuesize))
|
|
if t.indirectvalue {
|
|
*(*unsafe.Pointer)(v) = nil
|
|
} else {
|
|
memclrHasPointers(v, t.elem.size)
|
|
}
|
|
}
|
|
b.tophash[i] = empty
|
|
h.count--
|
|
break search
|
|
}
|
|
}
|
|
|
|
if h.flags&hashWriting == 0 {
|
|
throw("concurrent map writes")
|
|
}
|
|
h.flags &^= hashWriting
|
|
}
|
|
|
|
// mapiterinit initializes the hiter struct used for ranging over maps.
|
|
// The hiter struct pointed to by 'it' is allocated on the stack
|
|
// by the compilers order pass or on the heap by reflect_mapiterinit.
|
|
// Both need to have zeroed hiter since the struct contains pointers.
|
|
// Gccgo-specific: *it need not be zeroed by the compiler,
|
|
// and it's cheaper to zero it here.
|
|
func mapiterinit(t *maptype, h *hmap, it *hiter) {
|
|
it.key = nil
|
|
it.value = nil
|
|
it.t = nil
|
|
it.h = nil
|
|
it.buckets = nil
|
|
it.bptr = nil
|
|
it.overflow = nil
|
|
it.oldoverflow = nil
|
|
it.wrapped = false
|
|
it.i = 0
|
|
it.checkBucket = 0
|
|
|
|
if raceenabled && h != nil {
|
|
callerpc := getcallerpc()
|
|
racereadpc(unsafe.Pointer(h), callerpc, funcPC(mapiterinit))
|
|
}
|
|
|
|
if h == nil || h.count == 0 {
|
|
return
|
|
}
|
|
|
|
if unsafe.Sizeof(hiter{})/sys.PtrSize != 12 {
|
|
throw("hash_iter size incorrect") // see ../../cmd/internal/gc/reflect.go
|
|
}
|
|
it.t = t
|
|
it.h = h
|
|
|
|
// grab snapshot of bucket state
|
|
it.B = h.B
|
|
it.buckets = h.buckets
|
|
if t.bucket.kind&kindNoPointers != 0 {
|
|
// Allocate the current slice and remember pointers to both current and old.
|
|
// This preserves all relevant overflow buckets alive even if
|
|
// the table grows and/or overflow buckets are added to the table
|
|
// while we are iterating.
|
|
h.createOverflow()
|
|
it.overflow = h.extra.overflow
|
|
it.oldoverflow = h.extra.oldoverflow
|
|
}
|
|
|
|
// decide where to start
|
|
r := uintptr(fastrand())
|
|
if h.B > 31-bucketCntBits {
|
|
r += uintptr(fastrand()) << 31
|
|
}
|
|
it.startBucket = r & bucketMask(h.B)
|
|
it.offset = uint8(r >> h.B & (bucketCnt - 1))
|
|
|
|
// iterator state
|
|
it.bucket = it.startBucket
|
|
|
|
// Remember we have an iterator.
|
|
// Can run concurrently with another mapiterinit().
|
|
if old := h.flags; old&(iterator|oldIterator) != iterator|oldIterator {
|
|
atomic.Or8(&h.flags, iterator|oldIterator)
|
|
}
|
|
|
|
mapiternext(it)
|
|
}
|
|
|
|
func mapiternext(it *hiter) {
|
|
// Check preemption, since unlike gc we don't check on every call.
|
|
if getg().preempt {
|
|
checkPreempt()
|
|
}
|
|
|
|
h := it.h
|
|
if raceenabled {
|
|
callerpc := getcallerpc()
|
|
racereadpc(unsafe.Pointer(h), callerpc, funcPC(mapiternext))
|
|
}
|
|
if h.flags&hashWriting != 0 {
|
|
throw("concurrent map iteration and map write")
|
|
}
|
|
t := it.t
|
|
bucket := it.bucket
|
|
b := it.bptr
|
|
i := it.i
|
|
checkBucket := it.checkBucket
|
|
hashfn := t.key.hashfn
|
|
equalfn := t.key.equalfn
|
|
|
|
next:
|
|
if b == nil {
|
|
if bucket == it.startBucket && it.wrapped {
|
|
// end of iteration
|
|
it.key = nil
|
|
it.value = nil
|
|
return
|
|
}
|
|
if h.growing() && it.B == h.B {
|
|
// Iterator was started in the middle of a grow, and the grow isn't done yet.
|
|
// If the bucket we're looking at hasn't been filled in yet (i.e. the old
|
|
// bucket hasn't been evacuated) then we need to iterate through the old
|
|
// bucket and only return the ones that will be migrated to this bucket.
|
|
oldbucket := bucket & it.h.oldbucketmask()
|
|
b = (*bmap)(add(h.oldbuckets, oldbucket*uintptr(t.bucketsize)))
|
|
if !evacuated(b) {
|
|
checkBucket = bucket
|
|
} else {
|
|
b = (*bmap)(add(it.buckets, bucket*uintptr(t.bucketsize)))
|
|
checkBucket = noCheck
|
|
}
|
|
} else {
|
|
b = (*bmap)(add(it.buckets, bucket*uintptr(t.bucketsize)))
|
|
checkBucket = noCheck
|
|
}
|
|
bucket++
|
|
if bucket == bucketShift(it.B) {
|
|
bucket = 0
|
|
it.wrapped = true
|
|
}
|
|
i = 0
|
|
}
|
|
for ; i < bucketCnt; i++ {
|
|
offi := (i + it.offset) & (bucketCnt - 1)
|
|
if b.tophash[offi] == empty || b.tophash[offi] == evacuatedEmpty {
|
|
continue
|
|
}
|
|
k := add(unsafe.Pointer(b), dataOffset+uintptr(offi)*uintptr(t.keysize))
|
|
if t.indirectkey {
|
|
k = *((*unsafe.Pointer)(k))
|
|
}
|
|
v := add(unsafe.Pointer(b), dataOffset+bucketCnt*uintptr(t.keysize)+uintptr(offi)*uintptr(t.valuesize))
|
|
if checkBucket != noCheck && !h.sameSizeGrow() {
|
|
// Special case: iterator was started during a grow to a larger size
|
|
// and the grow is not done yet. We're working on a bucket whose
|
|
// oldbucket has not been evacuated yet. Or at least, it wasn't
|
|
// evacuated when we started the bucket. So we're iterating
|
|
// through the oldbucket, skipping any keys that will go
|
|
// to the other new bucket (each oldbucket expands to two
|
|
// buckets during a grow).
|
|
if t.reflexivekey || equalfn(k, k) {
|
|
// If the item in the oldbucket is not destined for
|
|
// the current new bucket in the iteration, skip it.
|
|
hash := hashfn(k, uintptr(h.hash0))
|
|
if hash&bucketMask(it.B) != checkBucket {
|
|
continue
|
|
}
|
|
} else {
|
|
// Hash isn't repeatable if k != k (NaNs). We need a
|
|
// repeatable and randomish choice of which direction
|
|
// to send NaNs during evacuation. We'll use the low
|
|
// bit of tophash to decide which way NaNs go.
|
|
// NOTE: this case is why we need two evacuate tophash
|
|
// values, evacuatedX and evacuatedY, that differ in
|
|
// their low bit.
|
|
if checkBucket>>(it.B-1) != uintptr(b.tophash[offi]&1) {
|
|
continue
|
|
}
|
|
}
|
|
}
|
|
if (b.tophash[offi] != evacuatedX && b.tophash[offi] != evacuatedY) ||
|
|
!(t.reflexivekey || equalfn(k, k)) {
|
|
// This is the golden data, we can return it.
|
|
// OR
|
|
// key!=key, so the entry can't be deleted or updated, so we can just return it.
|
|
// That's lucky for us because when key!=key we can't look it up successfully.
|
|
it.key = k
|
|
if t.indirectvalue {
|
|
v = *((*unsafe.Pointer)(v))
|
|
}
|
|
it.value = v
|
|
} else {
|
|
// The hash table has grown since the iterator was started.
|
|
// The golden data for this key is now somewhere else.
|
|
// Check the current hash table for the data.
|
|
// This code handles the case where the key
|
|
// has been deleted, updated, or deleted and reinserted.
|
|
// NOTE: we need to regrab the key as it has potentially been
|
|
// updated to an equal() but not identical key (e.g. +0.0 vs -0.0).
|
|
rk, rv := mapaccessK(t, h, k)
|
|
if rk == nil {
|
|
continue // key has been deleted
|
|
}
|
|
it.key = rk
|
|
it.value = rv
|
|
}
|
|
it.bucket = bucket
|
|
if it.bptr != b { // avoid unnecessary write barrier; see issue 14921
|
|
it.bptr = b
|
|
}
|
|
it.i = i + 1
|
|
it.checkBucket = checkBucket
|
|
return
|
|
}
|
|
b = b.overflow(t)
|
|
i = 0
|
|
goto next
|
|
}
|
|
|
|
func makeBucketArray(t *maptype, b uint8) (buckets unsafe.Pointer, nextOverflow *bmap) {
|
|
base := bucketShift(b)
|
|
nbuckets := base
|
|
// For small b, overflow buckets are unlikely.
|
|
// Avoid the overhead of the calculation.
|
|
if b >= 4 {
|
|
// Add on the estimated number of overflow buckets
|
|
// required to insert the median number of elements
|
|
// used with this value of b.
|
|
nbuckets += bucketShift(b - 4)
|
|
sz := t.bucket.size * nbuckets
|
|
up := roundupsize(sz)
|
|
if up != sz {
|
|
nbuckets = up / t.bucket.size
|
|
}
|
|
}
|
|
buckets = newarray(t.bucket, int(nbuckets))
|
|
if base != nbuckets {
|
|
// We preallocated some overflow buckets.
|
|
// To keep the overhead of tracking these overflow buckets to a minimum,
|
|
// we use the convention that if a preallocated overflow bucket's overflow
|
|
// pointer is nil, then there are more available by bumping the pointer.
|
|
// We need a safe non-nil pointer for the last overflow bucket; just use buckets.
|
|
nextOverflow = (*bmap)(add(buckets, base*uintptr(t.bucketsize)))
|
|
last := (*bmap)(add(buckets, (nbuckets-1)*uintptr(t.bucketsize)))
|
|
last.setoverflow(t, (*bmap)(buckets))
|
|
}
|
|
return buckets, nextOverflow
|
|
}
|
|
|
|
func hashGrow(t *maptype, h *hmap) {
|
|
// If we've hit the load factor, get bigger.
|
|
// Otherwise, there are too many overflow buckets,
|
|
// so keep the same number of buckets and "grow" laterally.
|
|
bigger := uint8(1)
|
|
if !overLoadFactor(h.count+1, h.B) {
|
|
bigger = 0
|
|
h.flags |= sameSizeGrow
|
|
}
|
|
oldbuckets := h.buckets
|
|
newbuckets, nextOverflow := makeBucketArray(t, h.B+bigger)
|
|
|
|
flags := h.flags &^ (iterator | oldIterator)
|
|
if h.flags&iterator != 0 {
|
|
flags |= oldIterator
|
|
}
|
|
// commit the grow (atomic wrt gc)
|
|
h.B += bigger
|
|
h.flags = flags
|
|
h.oldbuckets = oldbuckets
|
|
h.buckets = newbuckets
|
|
h.nevacuate = 0
|
|
h.noverflow = 0
|
|
|
|
if h.extra != nil && h.extra.overflow != nil {
|
|
// Promote current overflow buckets to the old generation.
|
|
if h.extra.oldoverflow != nil {
|
|
throw("oldoverflow is not nil")
|
|
}
|
|
h.extra.oldoverflow = h.extra.overflow
|
|
h.extra.overflow = nil
|
|
}
|
|
if nextOverflow != nil {
|
|
if h.extra == nil {
|
|
h.extra = new(mapextra)
|
|
}
|
|
h.extra.nextOverflow = nextOverflow
|
|
}
|
|
|
|
// the actual copying of the hash table data is done incrementally
|
|
// by growWork() and evacuate().
|
|
}
|
|
|
|
// overLoadFactor reports whether count items placed in 1<<B buckets is over loadFactor.
|
|
func overLoadFactor(count int, B uint8) bool {
|
|
return count > bucketCnt && uintptr(count) > loadFactorNum*(bucketShift(B)/loadFactorDen)
|
|
}
|
|
|
|
// tooManyOverflowBuckets reports whether noverflow buckets is too many for a map with 1<<B buckets.
|
|
// Note that most of these overflow buckets must be in sparse use;
|
|
// if use was dense, then we'd have already triggered regular map growth.
|
|
func tooManyOverflowBuckets(noverflow uint16, B uint8) bool {
|
|
// If the threshold is too low, we do extraneous work.
|
|
// If the threshold is too high, maps that grow and shrink can hold on to lots of unused memory.
|
|
// "too many" means (approximately) as many overflow buckets as regular buckets.
|
|
// See incrnoverflow for more details.
|
|
if B > 15 {
|
|
B = 15
|
|
}
|
|
// The compiler doesn't see here that B < 16; mask B to generate shorter shift code.
|
|
return noverflow >= uint16(1)<<(B&15)
|
|
}
|
|
|
|
// growing reports whether h is growing. The growth may be to the same size or bigger.
|
|
func (h *hmap) growing() bool {
|
|
return h.oldbuckets != nil
|
|
}
|
|
|
|
// sameSizeGrow reports whether the current growth is to a map of the same size.
|
|
func (h *hmap) sameSizeGrow() bool {
|
|
return h.flags&sameSizeGrow != 0
|
|
}
|
|
|
|
// noldbuckets calculates the number of buckets prior to the current map growth.
|
|
func (h *hmap) noldbuckets() uintptr {
|
|
oldB := h.B
|
|
if !h.sameSizeGrow() {
|
|
oldB--
|
|
}
|
|
return bucketShift(oldB)
|
|
}
|
|
|
|
// oldbucketmask provides a mask that can be applied to calculate n % noldbuckets().
|
|
func (h *hmap) oldbucketmask() uintptr {
|
|
return h.noldbuckets() - 1
|
|
}
|
|
|
|
func growWork(t *maptype, h *hmap, bucket uintptr) {
|
|
// make sure we evacuate the oldbucket corresponding
|
|
// to the bucket we're about to use
|
|
evacuate(t, h, bucket&h.oldbucketmask())
|
|
|
|
// evacuate one more oldbucket to make progress on growing
|
|
if h.growing() {
|
|
evacuate(t, h, h.nevacuate)
|
|
}
|
|
}
|
|
|
|
func bucketEvacuated(t *maptype, h *hmap, bucket uintptr) bool {
|
|
b := (*bmap)(add(h.oldbuckets, bucket*uintptr(t.bucketsize)))
|
|
return evacuated(b)
|
|
}
|
|
|
|
// evacDst is an evacuation destination.
|
|
type evacDst struct {
|
|
b *bmap // current destination bucket
|
|
i int // key/val index into b
|
|
k unsafe.Pointer // pointer to current key storage
|
|
v unsafe.Pointer // pointer to current value storage
|
|
}
|
|
|
|
func evacuate(t *maptype, h *hmap, oldbucket uintptr) {
|
|
b := (*bmap)(add(h.oldbuckets, oldbucket*uintptr(t.bucketsize)))
|
|
newbit := h.noldbuckets()
|
|
hashfn := t.key.hashfn
|
|
if !evacuated(b) {
|
|
// TODO: reuse overflow buckets instead of using new ones, if there
|
|
// is no iterator using the old buckets. (If !oldIterator.)
|
|
|
|
// xy contains the x and y (low and high) evacuation destinations.
|
|
var xy [2]evacDst
|
|
x := &xy[0]
|
|
x.b = (*bmap)(add(h.buckets, oldbucket*uintptr(t.bucketsize)))
|
|
x.k = add(unsafe.Pointer(x.b), dataOffset)
|
|
x.v = add(x.k, bucketCnt*uintptr(t.keysize))
|
|
|
|
if !h.sameSizeGrow() {
|
|
// Only calculate y pointers if we're growing bigger.
|
|
// Otherwise GC can see bad pointers.
|
|
y := &xy[1]
|
|
y.b = (*bmap)(add(h.buckets, (oldbucket+newbit)*uintptr(t.bucketsize)))
|
|
y.k = add(unsafe.Pointer(y.b), dataOffset)
|
|
y.v = add(y.k, bucketCnt*uintptr(t.keysize))
|
|
}
|
|
|
|
for ; b != nil; b = b.overflow(t) {
|
|
k := add(unsafe.Pointer(b), dataOffset)
|
|
v := add(k, bucketCnt*uintptr(t.keysize))
|
|
for i := 0; i < bucketCnt; i, k, v = i+1, add(k, uintptr(t.keysize)), add(v, uintptr(t.valuesize)) {
|
|
top := b.tophash[i]
|
|
if top == empty {
|
|
b.tophash[i] = evacuatedEmpty
|
|
continue
|
|
}
|
|
if top < minTopHash {
|
|
throw("bad map state")
|
|
}
|
|
k2 := k
|
|
if t.indirectkey {
|
|
k2 = *((*unsafe.Pointer)(k2))
|
|
}
|
|
var useY uint8
|
|
if !h.sameSizeGrow() {
|
|
// Compute hash to make our evacuation decision (whether we need
|
|
// to send this key/value to bucket x or bucket y).
|
|
hash := hashfn(k2, uintptr(h.hash0))
|
|
if h.flags&iterator != 0 && !t.reflexivekey && !t.key.equalfn(k2, k2) {
|
|
// If key != key (NaNs), then the hash could be (and probably
|
|
// will be) entirely different from the old hash. Moreover,
|
|
// it isn't reproducible. Reproducibility is required in the
|
|
// presence of iterators, as our evacuation decision must
|
|
// match whatever decision the iterator made.
|
|
// Fortunately, we have the freedom to send these keys either
|
|
// way. Also, tophash is meaningless for these kinds of keys.
|
|
// We let the low bit of tophash drive the evacuation decision.
|
|
// We recompute a new random tophash for the next level so
|
|
// these keys will get evenly distributed across all buckets
|
|
// after multiple grows.
|
|
useY = top & 1
|
|
top = tophash(hash)
|
|
} else {
|
|
if hash&newbit != 0 {
|
|
useY = 1
|
|
}
|
|
}
|
|
}
|
|
|
|
if evacuatedX+1 != evacuatedY {
|
|
throw("bad evacuatedN")
|
|
}
|
|
|
|
b.tophash[i] = evacuatedX + useY // evacuatedX + 1 == evacuatedY
|
|
dst := &xy[useY] // evacuation destination
|
|
|
|
if dst.i == bucketCnt {
|
|
dst.b = h.newoverflow(t, dst.b)
|
|
dst.i = 0
|
|
dst.k = add(unsafe.Pointer(dst.b), dataOffset)
|
|
dst.v = add(dst.k, bucketCnt*uintptr(t.keysize))
|
|
}
|
|
dst.b.tophash[dst.i&(bucketCnt-1)] = top // mask dst.i as an optimization, to avoid a bounds check
|
|
if t.indirectkey {
|
|
*(*unsafe.Pointer)(dst.k) = k2 // copy pointer
|
|
} else {
|
|
typedmemmove(t.key, dst.k, k) // copy value
|
|
}
|
|
if t.indirectvalue {
|
|
*(*unsafe.Pointer)(dst.v) = *(*unsafe.Pointer)(v)
|
|
} else {
|
|
typedmemmove(t.elem, dst.v, v)
|
|
}
|
|
dst.i++
|
|
// These updates might push these pointers past the end of the
|
|
// key or value arrays. That's ok, as we have the overflow pointer
|
|
// at the end of the bucket to protect against pointing past the
|
|
// end of the bucket.
|
|
dst.k = add(dst.k, uintptr(t.keysize))
|
|
dst.v = add(dst.v, uintptr(t.valuesize))
|
|
}
|
|
}
|
|
// Unlink the overflow buckets & clear key/value to help GC.
|
|
if h.flags&oldIterator == 0 && t.bucket.kind&kindNoPointers == 0 {
|
|
b := add(h.oldbuckets, oldbucket*uintptr(t.bucketsize))
|
|
// Preserve b.tophash because the evacuation
|
|
// state is maintained there.
|
|
ptr := add(b, dataOffset)
|
|
n := uintptr(t.bucketsize) - dataOffset
|
|
memclrHasPointers(ptr, n)
|
|
}
|
|
}
|
|
|
|
if oldbucket == h.nevacuate {
|
|
advanceEvacuationMark(h, t, newbit)
|
|
}
|
|
}
|
|
|
|
func advanceEvacuationMark(h *hmap, t *maptype, newbit uintptr) {
|
|
h.nevacuate++
|
|
// Experiments suggest that 1024 is overkill by at least an order of magnitude.
|
|
// Put it in there as a safeguard anyway, to ensure O(1) behavior.
|
|
stop := h.nevacuate + 1024
|
|
if stop > newbit {
|
|
stop = newbit
|
|
}
|
|
for h.nevacuate != stop && bucketEvacuated(t, h, h.nevacuate) {
|
|
h.nevacuate++
|
|
}
|
|
if h.nevacuate == newbit { // newbit == # of oldbuckets
|
|
// Growing is all done. Free old main bucket array.
|
|
h.oldbuckets = nil
|
|
// Can discard old overflow buckets as well.
|
|
// If they are still referenced by an iterator,
|
|
// then the iterator holds a pointers to the slice.
|
|
if h.extra != nil {
|
|
h.extra.oldoverflow = nil
|
|
}
|
|
h.flags &^= sameSizeGrow
|
|
}
|
|
}
|
|
|
|
func ismapkey(t *_type) bool {
|
|
return t.hashfn != nil
|
|
}
|
|
|
|
// Reflect stubs. Called from ../reflect/asm_*.s
|
|
|
|
//go:linkname reflect_makemap reflect.makemap
|
|
func reflect_makemap(t *maptype, cap int) *hmap {
|
|
// Check invariants and reflects math.
|
|
if sz := unsafe.Sizeof(hmap{}); sz != t.hmap.size {
|
|
println("runtime: sizeof(hmap) =", sz, ", t.hmap.size =", t.hmap.size)
|
|
throw("bad hmap size")
|
|
}
|
|
if !ismapkey(t.key) {
|
|
throw("runtime.reflect_makemap: unsupported map key type")
|
|
}
|
|
if t.key.size > maxKeySize && (!t.indirectkey || t.keysize != uint8(sys.PtrSize)) ||
|
|
t.key.size <= maxKeySize && (t.indirectkey || t.keysize != uint8(t.key.size)) {
|
|
throw("key size wrong")
|
|
}
|
|
if t.elem.size > maxValueSize && (!t.indirectvalue || t.valuesize != uint8(sys.PtrSize)) ||
|
|
t.elem.size <= maxValueSize && (t.indirectvalue || t.valuesize != uint8(t.elem.size)) {
|
|
throw("value size wrong")
|
|
}
|
|
if t.key.align > bucketCnt {
|
|
throw("key align too big")
|
|
}
|
|
if t.elem.align > bucketCnt {
|
|
throw("value align too big")
|
|
}
|
|
if t.key.size%uintptr(t.key.align) != 0 {
|
|
throw("key size not a multiple of key align")
|
|
}
|
|
if t.elem.size%uintptr(t.elem.align) != 0 {
|
|
throw("value size not a multiple of value align")
|
|
}
|
|
if bucketCnt < 8 {
|
|
throw("bucketsize too small for proper alignment")
|
|
}
|
|
if dataOffset%uintptr(t.key.align) != 0 {
|
|
throw("need padding in bucket (key)")
|
|
}
|
|
if dataOffset%uintptr(t.elem.align) != 0 {
|
|
throw("need padding in bucket (value)")
|
|
}
|
|
|
|
return makemap(t, cap, nil)
|
|
}
|
|
|
|
//go:linkname reflect_mapaccess reflect.mapaccess
|
|
func reflect_mapaccess(t *maptype, h *hmap, key unsafe.Pointer) unsafe.Pointer {
|
|
val, ok := mapaccess2(t, h, key)
|
|
if !ok {
|
|
// reflect wants nil for a missing element
|
|
val = nil
|
|
}
|
|
return val
|
|
}
|
|
|
|
//go:linkname reflect_mapassign reflect.mapassign
|
|
func reflect_mapassign(t *maptype, h *hmap, key unsafe.Pointer, val unsafe.Pointer) {
|
|
p := mapassign(t, h, key)
|
|
typedmemmove(t.elem, p, val)
|
|
}
|
|
|
|
//go:linkname reflect_mapdelete reflect.mapdelete
|
|
func reflect_mapdelete(t *maptype, h *hmap, key unsafe.Pointer) {
|
|
mapdelete(t, h, key)
|
|
}
|
|
|
|
//go:linkname reflect_mapiterinit reflect.mapiterinit
|
|
func reflect_mapiterinit(t *maptype, h *hmap) *hiter {
|
|
it := new(hiter)
|
|
mapiterinit(t, h, it)
|
|
return it
|
|
}
|
|
|
|
//go:linkname reflect_mapiternext reflect.mapiternext
|
|
func reflect_mapiternext(it *hiter) {
|
|
mapiternext(it)
|
|
}
|
|
|
|
//go:linkname reflect_mapiterkey reflect.mapiterkey
|
|
func reflect_mapiterkey(it *hiter) unsafe.Pointer {
|
|
return it.key
|
|
}
|
|
|
|
//go:linkname reflect_maplen reflect.maplen
|
|
func reflect_maplen(h *hmap) int {
|
|
if h == nil {
|
|
return 0
|
|
}
|
|
if raceenabled {
|
|
callerpc := getcallerpc()
|
|
racereadpc(unsafe.Pointer(h), callerpc, funcPC(reflect_maplen))
|
|
}
|
|
return h.count
|
|
}
|
|
|
|
//go:linkname reflect_ismapkey reflect.ismapkey
|
|
func reflect_ismapkey(t *_type) bool {
|
|
return ismapkey(t)
|
|
}
|
|
|
|
const maxZero = 1024 // must match value in ../cmd/compile/internal/gc/walk.go
|
|
var zeroVal [maxZero]byte
|