34 lines
1.3 KiB
Go
34 lines
1.3 KiB
Go
// Copyright 2023 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 abi
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const (
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// StackNosplitBase is the base maximum number of bytes that a chain of
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// NOSPLIT functions can use.
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//
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// This value must be multiplied by the stack guard multiplier, so do not
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// use it directly. See runtime/stack.go:stackNosplit and
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// cmd/internal/objabi/stack.go:StackNosplit.
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StackNosplitBase = 800
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// We have three different sequences for stack bounds checks, depending on
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// whether the stack frame of a function is small, big, or huge.
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// After a stack split check the SP is allowed to be StackSmall bytes below
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// the stack guard.
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//
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// Functions that need frames <= StackSmall can perform the stack check
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// using a single comparison directly between the stack guard and the SP
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// because we ensure that StackSmall bytes of stack space are available
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// beyond the stack guard.
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StackSmall = 128
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// Functions that need frames <= StackBig can assume that neither
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// SP-framesize nor stackGuard-StackSmall will underflow, and thus use a
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// more efficient check. In order to ensure this, StackBig must be <= the
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// size of the unmapped space at zero.
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StackBig = 4096
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)
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