wire: Pass pointers by interface to writeElement#3579
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davecgh merged 1 commit intodecred:masterfrom Dec 8, 2025
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For at least the past 5 years, due to garbage collector design, Go has not optimized small non-pointer types to fit inside interface headers, and instead always uses a pointer to data, if the type is not already a pointer. This means that writeElement, which was written before this time to avoid unnecessary heap allocations, was now causing heap allocations for each special cased non-pointer type. This commit rewrites writeElement to only special case pointers to types, and to pass all elements by pointer. Co-authored-by: David Hill <dhill@mindcry.org>
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I ran this over the weekend with some additional debug code to see if there were any stragglers. No additional cases were reported and everything ran great.
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For at least the past 5 years, due to garbage collector design, Go has not optimized small non-pointer types to fit inside interface headers, and instead always uses a pointer to data, if the type is not already a pointer. This means that writeElement, which was written before this time to avoid unnecessary heap allocations, was now causing heap allocations for each special cased non-pointer type.
This commit rewrites writeElement to only special case pointers to types, and to pass all elements by pointer.