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Diffstat (limited to 'vendor/modernc.org/memory/memory.go')
| -rw-r--r-- | vendor/modernc.org/memory/memory.go | 542 |
1 files changed, 542 insertions, 0 deletions
diff --git a/vendor/modernc.org/memory/memory.go b/vendor/modernc.org/memory/memory.go new file mode 100644 index 00000000..bbfaffcf --- /dev/null +++ b/vendor/modernc.org/memory/memory.go @@ -0,0 +1,542 @@ +// Copyright 2017 The Memory 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 memory implements a memory allocator. +// +// Build status +// +// available at https://modern-c.appspot.com/-/builder/?importpath=modernc.org%2fmemory +// +// Changelog +// +// 2017-10-03 Added alternative, unsafe.Pointer-based API. +// +// Package memory implements a memory allocator. +// +// Changelog +// +// 2017-10-03 Added alternative, unsafe.Pointer-based API. +// +// Benchmarks +// +// AMD Ryzen 9 3900X 12-Core Processor × 24 +// +// jnml@3900x:~/src/modernc.org/memory$ date ; go version ; go test -run @ -bench . -benchmem |& tee log +// Fri Nov 20 17:23:04 CET 2020 +// go version go1.15.5 linux/amd64 +// goos: linux +// goarch: amd64 +// pkg: modernc.org/memory +// BenchmarkFree16-24 141188362 8.26 ns/op 0 B/op 0 allocs/op +// BenchmarkFree32-24 100000000 11.4 ns/op 0 B/op 0 allocs/op +// BenchmarkFree64-24 67160647 18.3 ns/op 0 B/op 0 allocs/op +// BenchmarkCalloc16-24 60612698 19.8 ns/op 0 B/op 0 allocs/op +// BenchmarkCalloc32-24 47968105 23.8 ns/op 0 B/op 0 allocs/op +// BenchmarkCalloc64-24 40752181 28.6 ns/op 0 B/op 0 allocs/op +// BenchmarkGoCalloc16-24 66487354 17.8 ns/op 16 B/op 1 allocs/op +// BenchmarkGoCalloc32-24 56009206 21.2 ns/op 32 B/op 1 allocs/op +// BenchmarkGoCalloc64-24 52086571 23.4 ns/op 64 B/op 1 allocs/op +// BenchmarkMalloc16-24 113943390 10.2 ns/op 0 B/op 0 allocs/op +// BenchmarkMalloc32-24 113520471 10.2 ns/op 0 B/op 0 allocs/op +// BenchmarkMalloc64-24 108787056 10.7 ns/op 0 B/op 0 allocs/op +// BenchmarkUintptrFree16-24 146110286 7.94 ns/op 0 B/op 0 allocs/op +// BenchmarkUintptrFree32-24 93052707 12.0 ns/op 0 B/op 0 allocs/op +// BenchmarkUintptrFree64-24 69805262 17.3 ns/op 0 B/op 0 allocs/op +// BenchmarkUintptrCalloc16-24 85282725 13.7 ns/op 0 B/op 0 allocs/op +// BenchmarkUintptrCalloc32-24 66489789 17.9 ns/op 0 B/op 0 allocs/op +// BenchmarkUintptrCalloc64-24 53561092 22.7 ns/op 0 B/op 0 allocs/op +// BenchmarkUintptrMalloc16-24 222978858 5.28 ns/op 0 B/op 0 allocs/op +// BenchmarkUintptrMalloc32-24 210443384 5.30 ns/op 0 B/op 0 allocs/op +// BenchmarkUintptrMalloc64-24 213706227 5.47 ns/op 0 B/op 0 allocs/op +// PASS +// ok modernc.org/memory 70.528s +// jnml@3900x:~/src/modernc.org/memory$ +// +// Intel® Core™ i5-4670 CPU @ 3.40GHz × 4 +// +// ==== jnml@4670:~/src/modernc.org/memory> date ; go version ; go test -run @ -bench . -benchmem |& tee log +// Sat Dec 8 12:56:53 CET 2018 +// go version go1.11.2 linux/amd64 +// goos: linux +// goarch: amd64 +// pkg: modernc.org/memory +// BenchmarkFree16-4 100000000 14.7 ns/op 0 B/op 0 allocs/op +// BenchmarkFree32-4 100000000 20.5 ns/op 0 B/op 0 allocs/op +// BenchmarkFree64-4 50000000 32.8 ns/op 0 B/op 0 allocs/op +// BenchmarkCalloc16-4 50000000 24.4 ns/op 0 B/op 0 allocs/op +// BenchmarkCalloc32-4 50000000 29.2 ns/op 0 B/op 0 allocs/op +// BenchmarkCalloc64-4 50000000 35.7 ns/op 0 B/op 0 allocs/op +// BenchmarkGoCalloc16-4 50000000 27.0 ns/op 16 B/op 1 allocs/op +// BenchmarkGoCalloc32-4 50000000 27.3 ns/op 32 B/op 1 allocs/op +// BenchmarkGoCalloc64-4 30000000 37.9 ns/op 64 B/op 1 allocs/op +// BenchmarkMalloc16-4 100000000 12.9 ns/op 0 B/op 0 allocs/op +// BenchmarkMalloc32-4 100000000 12.9 ns/op 0 B/op 0 allocs/op +// BenchmarkMalloc64-4 100000000 13.2 ns/op 0 B/op 0 allocs/op +// BenchmarkUintptrFree16-4 100000000 12.0 ns/op 0 B/op 0 allocs/op +// BenchmarkUintptrFree32-4 100000000 17.5 ns/op 0 B/op 0 allocs/op +// BenchmarkUintptrFree64-4 50000000 28.9 ns/op 0 B/op 0 allocs/op +// BenchmarkUintptrCalloc16-4 100000000 17.8 ns/op 0 B/op 0 allocs/op +// BenchmarkUintptrCalloc32-4 100000000 22.9 ns/op 0 B/op 0 allocs/op +// BenchmarkUintptrCalloc64-4 50000000 29.6 ns/op 0 B/op 0 allocs/op +// BenchmarkUintptrMalloc16-4 200000000 7.31 ns/op 0 B/op 0 allocs/op +// BenchmarkUintptrMalloc32-4 200000000 7.47 ns/op 0 B/op 0 allocs/op +// BenchmarkUintptrMalloc64-4 200000000 7.68 ns/op 0 B/op 0 allocs/op +// PASS +// ok modernc.org/memory 73.859s +// // +// Intel® Xeon(R) CPU E5-1650 v2 @ 3.50GHz × 12 +// +// ==== jnml@e5-1650:~/src/modernc.org/memory> date ; go version ; go test -run @ -bench . -benchmem +// Fri Dec 7 14:18:50 CET 2018 +// go version go1.11.2 linux/amd64 +// goos: linux +// goarch: amd64 +// pkg: modernc.org/memory +// BenchmarkFree16-12 100000000 16.7 ns/op 0 B/op 0 allocs/op +// BenchmarkFree32-12 50000000 25.0 ns/op 0 B/op 0 allocs/op +// BenchmarkFree64-12 30000000 39.7 ns/op 0 B/op 0 allocs/op +// BenchmarkCalloc16-12 50000000 26.3 ns/op 0 B/op 0 allocs/op +// BenchmarkCalloc32-12 50000000 33.4 ns/op 0 B/op 0 allocs/op +// BenchmarkCalloc64-12 30000000 38.3 ns/op 0 B/op 0 allocs/op +// BenchmarkGoCalloc16-12 50000000 26.6 ns/op 16 B/op 1 allocs/op +// BenchmarkGoCalloc32-12 50000000 26.8 ns/op 32 B/op 1 allocs/op +// BenchmarkGoCalloc64-12 30000000 35.1 ns/op 64 B/op 1 allocs/op +// BenchmarkMalloc16-12 100000000 13.5 ns/op 0 B/op 0 allocs/op +// BenchmarkMalloc32-12 100000000 13.4 ns/op 0 B/op 0 allocs/op +// BenchmarkMalloc64-12 100000000 14.1 ns/op 0 B/op 0 allocs/op +// BenchmarkUintptrFree16-12 100000000 14.4 ns/op 0 B/op 0 allocs/op +// BenchmarkUintptrFree32-12 100000000 21.7 ns/op 0 B/op 0 allocs/op +// BenchmarkUintptrFree64-12 50000000 36.7 ns/op 0 B/op 0 allocs/op +// BenchmarkUintptrCalloc16-12 100000000 20.4 ns/op 0 B/op 0 allocs/op +// BenchmarkUintptrCalloc32-12 50000000 27.1 ns/op 0 B/op 0 allocs/op +// BenchmarkUintptrCalloc64-12 50000000 33.4 ns/op 0 B/op 0 allocs/op +// BenchmarkUintptrMalloc16-12 200000000 8.02 ns/op 0 B/op 0 allocs/op +// BenchmarkUintptrMalloc32-12 200000000 8.28 ns/op 0 B/op 0 allocs/op +// BenchmarkUintptrMalloc64-12 200000000 8.29 ns/op 0 B/op 0 allocs/op +// PASS +// ok modernc.org/memory 80.896s +package memory // import "modernc.org/memory" + +import ( + "fmt" + "math/bits" + "os" + "reflect" + "unsafe" +) + +const ( + headerSize = unsafe.Sizeof(page{}) + mallocAllign = 2 * unsafe.Sizeof(uintptr(0)) + maxSlotSize = 1 << maxSlotSizeLog + maxSlotSizeLog = pageSizeLog - 2 + pageAvail = pageSize - headerSize + pageMask = pageSize - 1 + pageSize = 1 << pageSizeLog +) + +func init() { + if unsafe.Sizeof(page{})%mallocAllign != 0 { + panic("internal error") + } +} + +// if n%m != 0 { n += m-n%m }. m must be a power of 2. +func roundup(n, m int) int { return (n + m - 1) &^ (m - 1) } + +type node struct { + prev, next uintptr // *node +} + +type page struct { + brk int + log uint + size int + used int +} + +// Allocator allocates and frees memory. Its zero value is ready for use. The +// exported counters are updated only when build tag memory.counters is +// present. +type Allocator struct { + Allocs int // # of allocs. + Bytes int // Asked from OS. + cap [64]int + lists [64]uintptr // *node + Mmaps int // Asked from OS. + pages [64]uintptr // *page + regs map[uintptr]struct{} // map[*page]struct{} +} + +func (a *Allocator) mmap(size int) (uintptr /* *page */, error) { + p, size, err := mmap(size) + if err != nil { + return 0, err + } + + if counters { + a.Mmaps++ + a.Bytes += size + } + if a.regs == nil { + a.regs = map[uintptr]struct{}{} + } + (*page)(unsafe.Pointer(p)).size = size + a.regs[p] = struct{}{} + return p, nil +} + +func (a *Allocator) newPage(size int) (uintptr /* *page */, error) { + size += int(headerSize) + p, err := a.mmap(size) + if err != nil { + return 0, err + } + + (*page)(unsafe.Pointer(p)).log = 0 + return p, nil +} + +func (a *Allocator) newSharedPage(log uint) (uintptr /* *page */, error) { + if a.cap[log] == 0 { + a.cap[log] = int(pageAvail) / (1 << log) + } + size := int(headerSize) + a.cap[log]<<log + p, err := a.mmap(size) + if err != nil { + return 0, err + } + + a.pages[log] = p + (*page)(unsafe.Pointer(p)).log = log + return p, nil +} + +func (a *Allocator) unmap(p uintptr /* *page */) error { + delete(a.regs, p) + if counters { + a.Mmaps-- + } + return unmap(p, (*page)(unsafe.Pointer(p)).size) +} + +// UintptrCalloc is like Calloc except it returns an uintptr. +func (a *Allocator) UintptrCalloc(size int) (r uintptr, err error) { + if trace { + defer func() { + fmt.Fprintf(os.Stderr, "Calloc(%#x) %#x, %v\n", size, r, err) + }() + } + if r, err = a.UintptrMalloc(size); r == 0 || err != nil { + return 0, err + } + b := ((*rawmem)(unsafe.Pointer(r)))[:size:size] + for i := range b { + b[i] = 0 + } + return r, nil +} + +// UintptrFree is like Free except its argument is an uintptr, which must have +// been acquired from UintptrCalloc or UintptrMalloc or UintptrRealloc. +func (a *Allocator) UintptrFree(p uintptr) (err error) { + if trace { + defer func() { + fmt.Fprintf(os.Stderr, "Free(%#x) %v\n", p, err) + }() + } + if p == 0 { + return nil + } + + if counters { + a.Allocs-- + } + pg := p &^ uintptr(pageMask) + log := (*page)(unsafe.Pointer(pg)).log + if log == 0 { + if counters { + a.Bytes -= (*page)(unsafe.Pointer(pg)).size + } + return a.unmap(pg) + } + + (*node)(unsafe.Pointer(p)).prev = 0 + (*node)(unsafe.Pointer(p)).next = a.lists[log] + if next := (*node)(unsafe.Pointer(p)).next; next != 0 { + (*node)(unsafe.Pointer(next)).prev = p + } + a.lists[log] = p + (*page)(unsafe.Pointer(pg)).used-- + if (*page)(unsafe.Pointer(pg)).used != 0 { + return nil + } + + for i := 0; i < (*page)(unsafe.Pointer(pg)).brk; i++ { + n := pg + headerSize + uintptr(i)<<log + next := (*node)(unsafe.Pointer(n)).next + prev := (*node)(unsafe.Pointer(n)).prev + switch { + case prev == 0: + a.lists[log] = next + if next != 0 { + (*node)(unsafe.Pointer(next)).prev = 0 + } + case next == 0: + (*node)(unsafe.Pointer(prev)).next = 0 + default: + (*node)(unsafe.Pointer(prev)).next = next + (*node)(unsafe.Pointer(next)).prev = prev + } + } + + if a.pages[log] == pg { + a.pages[log] = 0 + } + if counters { + a.Bytes -= (*page)(unsafe.Pointer(pg)).size + } + return a.unmap(pg) +} + +// UintptrMalloc is like Malloc except it returns an uinptr. +func (a *Allocator) UintptrMalloc(size int) (r uintptr, err error) { + if trace { + defer func() { + fmt.Fprintf(os.Stderr, "Malloc(%#x) %#x, %v\n", size, r, err) + }() + } + if size < 0 { + panic("invalid malloc size") + } + + if size == 0 { + return 0, nil + } + + if counters { + a.Allocs++ + } + log := uint(bits.Len(uint((size+int(mallocAllign)-1)&^int(mallocAllign-1) - 1))) + if log > maxSlotSizeLog { + p, err := a.newPage(size) + if err != nil { + return 0, err + } + + return p + headerSize, nil + } + + if a.lists[log] == 0 && a.pages[log] == 0 { + if _, err := a.newSharedPage(log); err != nil { + return 0, err + } + } + + if p := a.pages[log]; p != 0 { + (*page)(unsafe.Pointer(p)).used++ + (*page)(unsafe.Pointer(p)).brk++ + if (*page)(unsafe.Pointer(p)).brk == a.cap[log] { + a.pages[log] = 0 + } + return p + headerSize + uintptr((*page)(unsafe.Pointer(p)).brk-1)<<log, nil + } + + n := a.lists[log] + p := n &^ uintptr(pageMask) + a.lists[log] = (*node)(unsafe.Pointer(n)).next + if next := (*node)(unsafe.Pointer(n)).next; next != 0 { + (*node)(unsafe.Pointer(next)).prev = 0 + } + (*page)(unsafe.Pointer(p)).used++ + return n, nil +} + +// UintptrRealloc is like Realloc except its first argument is an uintptr, +// which must have been returned from UintptrCalloc, UintptrMalloc or +// UintptrRealloc. +func (a *Allocator) UintptrRealloc(p uintptr, size int) (r uintptr, err error) { + if trace { + defer func() { + fmt.Fprintf(os.Stderr, "UnsafeRealloc(%#x, %#x) %#x, %v\n", p, size, r, err) + }() + } + switch { + case p == 0: + return a.UintptrMalloc(size) + case size == 0 && p != 0: + return 0, a.UintptrFree(p) + } + + us := UintptrUsableSize(p) + if us > size { + return p, nil + } + + if r, err = a.UintptrMalloc(size); err != nil { + return 0, err + } + + if us < size { + size = us + } + copy((*rawmem)(unsafe.Pointer(r))[:size:size], (*rawmem)(unsafe.Pointer(p))[:size:size]) + return r, a.UintptrFree(p) +} + +// UintptrUsableSize is like UsableSize except its argument is an uintptr, +// which must have been returned from UintptrCalloc, UintptrMalloc or +// UintptrRealloc. +func UintptrUsableSize(p uintptr) (r int) { + if trace { + defer func() { + fmt.Fprintf(os.Stderr, "UsableSize(%#x) %#x\n", p, r) + }() + } + if p == 0 { + return 0 + } + + return usableSize(p) +} + +func usableSize(p uintptr) (r int) { + pg := p &^ uintptr(pageMask) + if log := (*page)(unsafe.Pointer(pg)).log; log != 0 { + return 1 << log + } + + return (*page)(unsafe.Pointer(pg)).size - int(headerSize) +} + +// Calloc is like Malloc except the allocated memory is zeroed. +func (a *Allocator) Calloc(size int) (r []byte, err error) { + p, err := a.UintptrCalloc(size) + if err != nil { + return nil, err + } + + var b []byte + sh := (*reflect.SliceHeader)(unsafe.Pointer(&b)) + sh.Cap = usableSize(p) + sh.Data = p + sh.Len = size + return b, nil +} + +// Close releases all OS resources used by a and sets it to its zero value. +// +// It's not necessary to Close the Allocator when exiting a process. +func (a *Allocator) Close() (err error) { + for p := range a.regs { + if e := a.unmap(p); e != nil && err == nil { + err = e + } + } + *a = Allocator{} + return err +} + +// Free deallocates memory (as in C.free). The argument of Free must have been +// acquired from Calloc or Malloc or Realloc. +func (a *Allocator) Free(b []byte) (err error) { + if b = b[:cap(b)]; len(b) == 0 { + return nil + } + + return a.UintptrFree(uintptr(unsafe.Pointer(&b[0]))) +} + +// Malloc allocates size bytes and returns a byte slice of the allocated +// memory. The memory is not initialized. Malloc panics for size < 0 and +// returns (nil, nil) for zero size. +// +// It's ok to reslice the returned slice but the result of appending to it +// cannot be passed to Free or Realloc as it may refer to a different backing +// array afterwards. +func (a *Allocator) Malloc(size int) (r []byte, err error) { + p, err := a.UintptrMalloc(size) + if p == 0 || err != nil { + return nil, err + } + + sh := (*reflect.SliceHeader)(unsafe.Pointer(&r)) + sh.Cap = usableSize(p) + sh.Data = p + sh.Len = size + return r, nil +} + +// Realloc changes the size of the backing array of b to size bytes or returns +// an error, if any. The contents will be unchanged in the range from the +// start of the region up to the minimum of the old and new sizes. If the +// new size is larger than the old size, the added memory will not be +// initialized. If b's backing array is of zero size, then the call is +// equivalent to Malloc(size), for all values of size; if size is equal to +// zero, and b's backing array is not of zero size, then the call is equivalent +// to Free(b). Unless b's backing array is of zero size, it must have been +// returned by an earlier call to Malloc, Calloc or Realloc. If the area +// pointed to was moved, a Free(b) is done. +func (a *Allocator) Realloc(b []byte, size int) (r []byte, err error) { + var p uintptr + if b = b[:cap(b)]; len(b) != 0 { + p = uintptr(unsafe.Pointer(&b[0])) + } + if p, err = a.UintptrRealloc(p, size); p == 0 || err != nil { + return nil, err + } + + sh := (*reflect.SliceHeader)(unsafe.Pointer(&r)) + sh.Cap = usableSize(p) + sh.Data = p + sh.Len = size + return r, nil +} + +// UsableSize reports the size of the memory block allocated at p, which must +// point to the first byte of a slice returned from Calloc, Malloc or Realloc. +// The allocated memory block size can be larger than the size originally +// requested from Calloc, Malloc or Realloc. +func UsableSize(p *byte) (r int) { return UintptrUsableSize(uintptr(unsafe.Pointer(p))) } + +// UnsafeCalloc is like Calloc except it returns an unsafe.Pointer. +func (a *Allocator) UnsafeCalloc(size int) (r unsafe.Pointer, err error) { + p, err := a.UintptrCalloc(size) + if err != nil { + return nil, err + } + + return unsafe.Pointer(p), nil +} + +// UnsafeFree is like Free except its argument is an unsafe.Pointer, which must +// have been acquired from UnsafeCalloc or UnsafeMalloc or UnsafeRealloc. +func (a *Allocator) UnsafeFree(p unsafe.Pointer) (err error) { return a.UintptrFree(uintptr(p)) } + +// UnsafeMalloc is like Malloc except it returns an unsafe.Pointer. +func (a *Allocator) UnsafeMalloc(size int) (r unsafe.Pointer, err error) { + p, err := a.UintptrMalloc(size) + if err != nil { + return nil, err + } + + return unsafe.Pointer(p), nil +} + +// UnsafeRealloc is like Realloc except its first argument is an +// unsafe.Pointer, which must have been returned from UnsafeCalloc, +// UnsafeMalloc or UnsafeRealloc. +func (a *Allocator) UnsafeRealloc(p unsafe.Pointer, size int) (r unsafe.Pointer, err error) { + q, err := a.UintptrRealloc(uintptr(p), size) + if err != nil { + return nil, err + } + + return unsafe.Pointer(q), nil +} + +// UnsafeUsableSize is like UsableSize except its argument is an +// unsafe.Pointer, which must have been returned from UnsafeCalloc, +// UnsafeMalloc or UnsafeRealloc. +func UnsafeUsableSize(p unsafe.Pointer) (r int) { return UintptrUsableSize(uintptr(p)) } |