What’s New in Go 1.17? Performance Boosts, ARM Support, and Unsafe Enhancements

Go 1.17 has been officially released. The new compiler adopts a different function‑parameter and result‑passing strategy, which the Go team says improves program performance by about 5% and reduces amd64 binary size by roughly 2%, with plans to support more platforms.

The release also adds support for the 64‑bit ARM architecture on Windows, allowing Go programs to run natively on more devices.

A new “pruned module graphs” feature is introduced. When a module’s go.mod file specifies Go 1.17 or later, the module graph includes only the direct dependencies of other Go 1.17 modules, not all transitive dependencies, helping to avoid unnecessary downloads and speeding up development.

Language‑level improvements include three changes:

Support for converting a slice to an array pointer.

New unsafe.Add function: unsafe.Add(ptr, len) adds len to ptr and returns the updated unsafe.Pointer.

New unsafe.Slice function: for a *T pointer, unsafe.Slice(ptr, len) returns a []T slice whose underlying array starts at ptr with length and capacity len.

For a complete list of changes, see the Go 1.17 Release Notes at https://golang.org/doc/go1.17. The binaries can be downloaded from https://golang.org/dl/.