core/state: reduce allocation in updateStateObject

[MariusVanDerWijden]

I couldn't really believe it myself, but turns out this saves us one heap allocation

goos: linux
goarch: amd64
pkg: github.com/ethereum/go-ethereum/core/state
cpu: Intel(R) Core(TM) Ultra 7 155U
                     │ /tmp/old.txt │            /tmp/new.txt             │
                     │    sec/op    │   sec/op     vs base                │
UpdateStateObject-14   782.6n ± 19%   674.1n ± 6%  -13.86% (p=0.002 n=10)

                     │ /tmp/old.txt │           /tmp/new.txt            │
                     │     B/op     │    B/op     vs base               │
UpdateStateObject-14     368.0 ± 0%   344.0 ± 0%  -6.52% (p=0.000 n=10)

                     │ /tmp/old.txt │            /tmp/new.txt            │
                     │  allocs/op   │ allocs/op   vs base                │
UpdateStateObject-14     8.000 ± 0%   7.000 ± 0%  -12.50% (p=0.000 n=10)

Benchmark:

func BenchmarkUpdateStateObject(b *testing.B) {
	db := NewDatabaseForTesting()
	orig, _ := New(types.EmptyRootHash, db)

	// Fill up the initial states
	obj := orig.getOrNewStateObject(common.BytesToAddress([]byte{}))
	obj.AddBalance(uint256.NewInt(uint64(1)))
	obj.data.Root = common.HexToHash("0xdeadbeef")
	for range b.N {
		orig.updateStateObject(obj)
	}
}

[fjl]

Ahh, right, so it saves an allocation because the variable escapes to heap when passed as any to fmt.Errorf.

[s1na]

LGTM