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https://github.com/golang/go
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77a2113925
Consider an interface value i of type I and concrete value c of type C. Prior to this CL, i==c was evaluated as I(c) == i Evaluating I(c) can allocate. This CL changes the evaluation of i==c to x, ok := i.(C); ok && x == c The new generated code is shorter and does not allocate directly. If C is small, as it is in every instance in the stdlib, the new code also uses less stack space and makes one runtime call instead of two. If C is very large, the original implementation is used. The cutoff for "very large" is 1<<16, following the stack vs heap cutoff used elsewhere. This kind of comparison occurs in 38 places in the stdlib, mostly in the net and os packages. benchmark old ns/op new ns/op delta BenchmarkEqEfaceConcrete 29.5 7.92 -73.15% BenchmarkEqIfaceConcrete 32.1 7.90 -75.39% BenchmarkNeEfaceConcrete 29.9 7.90 -73.58% BenchmarkNeIfaceConcrete 35.9 7.90 -77.99% Fixes #9370. Change-Id: I7c4555950bcd6406ee5c613be1f2128da2c9a2b7 Reviewed-on: https://go-review.googlesource.com/2096 Reviewed-by: Russ Cox <rsc@golang.org> Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
128 lines
3.9 KiB
Go
128 lines
3.9 KiB
Go
// errorcheck
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// Copyright 2014 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Verify that concrete/interface comparisons are
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// typechecked correctly by the compiler.
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package main
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type I interface {
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Method()
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}
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type C int
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func (C) Method() {}
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type G func()
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func (G) Method() {}
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var (
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e interface{}
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i I
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c C
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n int
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f func()
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g G
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)
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var (
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_ = e == c
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_ = e != c
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_ = e >= c // ERROR "invalid operation.*not defined"
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_ = c == e
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_ = c != e
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_ = c >= e // ERROR "invalid operation.*not defined"
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_ = i == c
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_ = i != c
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_ = i >= c // ERROR "invalid operation.*not defined"
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_ = c == i
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_ = c != i
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_ = c >= i // ERROR "invalid operation.*not defined"
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_ = e == n
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_ = e != n
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_ = e >= n // ERROR "invalid operation.*not defined"
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_ = n == e
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_ = n != e
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_ = n >= e // ERROR "invalid operation.*not defined"
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// i and n are not assignable to each other
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_ = i == n // ERROR "invalid operation.*mismatched types"
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_ = i != n // ERROR "invalid operation.*mismatched types"
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_ = i >= n // ERROR "invalid operation.*mismatched types"
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_ = n == i // ERROR "invalid operation.*mismatched types"
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_ = n != i // ERROR "invalid operation.*mismatched types"
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_ = n >= i // ERROR "invalid operation.*mismatched types"
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_ = e == 1
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_ = e != 1
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_ = e >= 1 // ERROR "invalid operation.*not defined"
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_ = 1 == e
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_ = 1 != e
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_ = 1 >= e // ERROR "invalid operation.*not defined"
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_ = i == 1 // ERROR "invalid operation.*mismatched types"
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_ = i != 1 // ERROR "invalid operation.*mismatched types"
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_ = i >= 1 // ERROR "invalid operation.*mismatched types"
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_ = 1 == i // ERROR "invalid operation.*mismatched types"
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_ = 1 != i // ERROR "invalid operation.*mismatched types"
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_ = 1 >= i // ERROR "invalid operation.*mismatched types"
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_ = e == f // ERROR "invalid operation.*not defined"
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_ = e != f // ERROR "invalid operation.*not defined"
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_ = e >= f // ERROR "invalid operation.*not defined"
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_ = f == e // ERROR "invalid operation.*not defined"
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_ = f != e // ERROR "invalid operation.*not defined"
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_ = f >= e // ERROR "invalid operation.*not defined"
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_ = i == f // ERROR "invalid operation.*mismatched types"
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_ = i != f // ERROR "invalid operation.*mismatched types"
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_ = i >= f // ERROR "invalid operation.*mismatched types"
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_ = f == i // ERROR "invalid operation.*mismatched types"
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_ = f != i // ERROR "invalid operation.*mismatched types"
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_ = f >= i // ERROR "invalid operation.*mismatched types"
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_ = e == g // ERROR "invalid operation.*not defined"
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_ = e != g // ERROR "invalid operation.*not defined"
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_ = e >= g // ERROR "invalid operation.*not defined"
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_ = g == e // ERROR "invalid operation.*not defined"
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_ = g != e // ERROR "invalid operation.*not defined"
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_ = g >= e // ERROR "invalid operation.*not defined"
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_ = i == g // ERROR "invalid operation.*not defined"
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_ = i != g // ERROR "invalid operation.*not defined"
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_ = i >= g // ERROR "invalid operation.*not defined"
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_ = g == i // ERROR "invalid operation.*not defined"
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_ = g != i // ERROR "invalid operation.*not defined"
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_ = g >= i // ERROR "invalid operation.*not defined"
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_ = _ == e // ERROR "cannot use _ as value"
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_ = _ == i // ERROR "cannot use _ as value"
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_ = _ == c // ERROR "cannot use _ as value"
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_ = _ == n // ERROR "cannot use _ as value"
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_ = _ == f // ERROR "cannot use _ as value"
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_ = _ == g // ERROR "cannot use _ as value"
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_ = e == _ // ERROR "cannot use _ as value"
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_ = i == _ // ERROR "cannot use _ as value"
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_ = c == _ // ERROR "cannot use _ as value"
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_ = n == _ // ERROR "cannot use _ as value"
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_ = f == _ // ERROR "cannot use _ as value"
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_ = g == _ // ERROR "cannot use _ as value"
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_ = _ == _ // ERROR "cannot use _ as value"
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_ = e ^ c // ERROR "invalid operation.*mismatched types"
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_ = c ^ e // ERROR "invalid operation.*mismatched types"
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_ = 1 ^ e // ERROR "invalid operation.*mismatched types"
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_ = e ^ 1 // ERROR "invalid operation.*mismatched types"
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_ = 1 ^ c
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_ = c ^ 1
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)
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