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Ayke van Laethem
134de98ba5
Instead of referring to an unused global, use a constant value. This is safe even when using `-gc=none` (since no actual memory gets allocated) which wasn't the case before. It should also reduce binary size by a few bytes for most programs.
30 lines
1.1 KiB
Go
30 lines
1.1 KiB
Go
package runtime
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// Shared code for the various garbage collectors.
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import "unsafe"
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// Special alloc function that should never actually be called.
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// It is used instead of normal alloc in //go:noheap functions, and must either
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// be optimized away or throw a linker error.
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func alloc_noheap(size uintptr, layout unsafe.Pointer) unsafe.Pointer
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// Special alloc function that returns a sentinel value that can never be on the
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// heap or match any other valid pointer. An alloc(0, xxx) call can be safely
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// converted to an alloc_zero(0, xxx) call as an optimization.
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//
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// It is always a good idea to inline this function, since the result is a
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// constant. Marking it as go:inline to be sure even though the compiler should
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// already be doing this.
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//
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//go:inline
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func alloc_zero(size uintptr, layout unsafe.Pointer) unsafe.Pointer {
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// Returning a constant here is safe, since the Go spec does not require
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// multiple zero-sized allocations to be unequal when compared for equality:
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//
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// > Pointers to distinct zero-size variables may or may not be equal.
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//
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// Source: https://go.dev/ref/spec#Comparison_operators
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return unsafe.Pointer(zeroSizeAllocPtr)
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}
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