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Nia Waldvogel
9bcca974ba
The GC bitmap length is measured in multiples of the pointer alignment. This is equal to the pointer size on all architectures except AVR. Replace the hardcoded lengths with lengths that are computed naturally.
27 lines
708 B
Go
27 lines
708 B
Go
package gclayout
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import "unsafe"
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// Internal constants for gc layout
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// See runtime/gc_precise.go
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type Layout uintptr
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const (
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// 16-bit int => bits = 4
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// 32-bit int => bits = 5
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// 64-bit int => bits = 6
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sizeBits = 4 + unsafe.Sizeof(uintptr(0))/4
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ptrAlign = unsafe.Alignof(uintptr(0))
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sizeShift = sizeBits + 1
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NoPtrs = Layout((0 << sizeShift) | (1 << 1) | 1)
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Pointer = Layout((1 << sizeShift) | ((unsafe.Sizeof(unsafe.Pointer(nil)) / ptrAlign) << 1) | 1)
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String = Layout((1 << sizeShift) | ((unsafe.Sizeof("") / ptrAlign) << 1) | 1)
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Slice = Layout((1 << sizeShift) | ((unsafe.Sizeof([]byte{}) / ptrAlign) << 1) | 1)
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)
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func (l Layout) AsPtr() unsafe.Pointer { return unsafe.Pointer(l) }
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