// Copyright 2018 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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// +build js,wasm
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package runtime
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import (
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"runtime/internal/sys"
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"unsafe"
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)
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// Don't split the stack as this function may be invoked without a valid G,
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// which prevents us from allocating more stack.
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//go:nosplit
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func sysAlloc(n uintptr, sysStat *uint64) unsafe.Pointer {
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p := sysReserve(nil, n)
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sysMap(p, n, sysStat)
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return p
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}
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func sysUnused(v unsafe.Pointer, n uintptr) {
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}
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func sysUsed(v unsafe.Pointer, n uintptr) {
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}
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// Don't split the stack as this function may be invoked without a valid G,
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// which prevents us from allocating more stack.
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//go:nosplit
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func sysFree(v unsafe.Pointer, n uintptr, sysStat *uint64) {
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mSysStatDec(sysStat, n)
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}
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func sysFault(v unsafe.Pointer, n uintptr) {
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}
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var reserveEnd uintptr
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func sysReserve(v unsafe.Pointer, n uintptr) unsafe.Pointer {
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// TODO(neelance): maybe unify with mem_plan9.go, depending on how https://github.com/WebAssembly/design/blob/master/FutureFeatures.md#finer-grained-control-over-memory turns out
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if reserveEnd < lastmoduledatap.end {
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reserveEnd = lastmoduledatap.end
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}
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if uintptr(v) < reserveEnd {
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v = unsafe.Pointer(reserveEnd)
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}
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reserveEnd = uintptr(v) + n
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current := currentMemory()
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needed := int32(reserveEnd/sys.DefaultPhysPageSize + 1)
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if current < needed {
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if growMemory(needed-current) == -1 {
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return nil
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}
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}
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return v
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}
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func currentMemory() int32
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func growMemory(pages int32) int32
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func sysMap(v unsafe.Pointer, n uintptr, sysStat *uint64) {
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mSysStatInc(sysStat, n)
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}
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