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cmd/compile: statically initialize some interface values
When possible, emit static data rather than init functions for interface values. This: * cuts 32k off cmd/go * removes several error values from runtime init * cuts the size of the image/color/palette compiled package from 103k to 34k * reduces the time to build the package in #15520 from 8s to 1.5s Fixes #6289 Fixes #15528 Change-Id: I317112da17aadb180c958ea328ab380f83e640b4 Reviewed-on: https://go-review.googlesource.com/26668 Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This commit is contained in:
parent
b8eb5b53ea
commit
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@ -978,8 +978,8 @@ func typename(t *Type) *Node {
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}
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func itabname(t, itype *Type) *Node {
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if t == nil || (t.IsPtr() && t.Elem() == nil) || t.IsUntyped() {
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Fatalf("itabname %v", t)
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if t == nil || (t.IsPtr() && t.Elem() == nil) || t.IsUntyped() || !itype.IsInterface() || itype.IsEmptyInterface() {
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Fatalf("itabname(%v, %v)", t, itype)
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}
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s := Pkglookup(fmt.Sprintf("%-v,%-v", t, itype), itabpkg)
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if s.Def == nil {
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@ -4,9 +4,7 @@
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package gc
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import (
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"fmt"
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)
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import "fmt"
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// static initialization
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const (
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@ -479,6 +477,67 @@ func staticassign(l *Node, r *Node, out *[]*Node) bool {
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} else {
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closuredebugruntimecheck(r)
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}
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case OCONVIFACE:
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// This logic is mirrored in isStaticCompositeLiteral.
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// If you change something here, change it there, and vice versa.
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// Determine the underlying concrete type and value we are converting from.
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val := r
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for val.Op == OCONVIFACE {
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val = val.Left
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}
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if val.Type.IsInterface() {
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// val is an interface type.
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// If val is nil, we can statically initialize l;
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// both words are zero and so there no work to do, so report success.
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// If val is non-nil, we have no concrete type to record,
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// and we won't be able to statically initialize its value, so report failure.
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return Isconst(val, CTNIL)
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}
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var itab *Node
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if l.Type.IsEmptyInterface() {
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itab = typename(val.Type)
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} else {
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itab = itabname(val.Type, l.Type)
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}
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// Create a copy of l to modify while we emit data.
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n := *l
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// Emit itab, advance offset.
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gdata(&n, itab, Widthptr)
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n.Xoffset += int64(Widthptr)
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// Emit data.
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if isdirectiface(val.Type) {
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if Isconst(val, CTNIL) {
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// Nil is zero, nothing to do.
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return true
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}
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// Copy val directly into n.
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n.Type = val.Type
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setlineno(val)
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a := Nod(OXXX, nil, nil)
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*a = n
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a.Orig = a
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if !staticassign(a, val, out) {
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*out = append(*out, Nod(OAS, a, val))
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}
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} else {
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// Construct temp to hold val, write pointer to temp into n.
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a := staticname(val.Type)
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inittemps[val] = a
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if !staticassign(a, val, out) {
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*out = append(*out, Nod(OAS, a, val))
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}
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ptr := Nod(OADDR, a, nil)
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n.Type = Ptrto(val.Type)
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gdata(&n, ptr, Widthptr)
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}
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return true
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}
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//dump("not static", r);
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@ -593,6 +652,19 @@ func isStaticCompositeLiteral(n *Node) bool {
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return true
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case OLITERAL:
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return true
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case OCONVIFACE:
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// See staticassign's OCONVIFACE case for comments.
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val := n
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for val.Op == OCONVIFACE {
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val = val.Left
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}
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if val.Type.IsInterface() {
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return Isconst(val, CTNIL)
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}
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if isdirectiface(val.Type) && Isconst(val, CTNIL) {
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return true
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}
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return isStaticCompositeLiteral(val)
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}
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return false
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}
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131
test/fixedbugs/issue15528.go
Normal file
131
test/fixedbugs/issue15528.go
Normal file
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@ -0,0 +1,131 @@
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// run
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// Copyright 2016 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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package main
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import (
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"fmt"
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"io"
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"os"
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"reflect"
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"unsafe"
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)
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type RWS struct{}
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func (x *RWS) Read(p []byte) (n int, err error) { return }
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func (x *RWS) Write(p []byte) (n int, err error) { return }
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func (x *RWS) Seek(offset int64, whence int) (n int64, err error) { return }
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func (x *RWS) String() string { return "rws" }
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func makeRWS() io.ReadWriteSeeker { return &RWS{} }
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func makeStringer() fmt.Stringer { return &RWS{} }
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// Test correct construction of static empty interface values
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var efaces = [...]struct {
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x interface{}
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s string
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}{
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{nil, "<nil> <nil>"},
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{1, "int 1"},
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{int(1), "int 1"},
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{Int(int(2)), "main.Int Int=2"},
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{int(Int(3)), "int 3"},
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{[1]int{2}, "[1]int [2]"},
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{io.Reader(io.ReadWriter(io.ReadWriteSeeker(nil))), "<nil> <nil>"},
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{io.Reader(io.ReadWriter(io.ReadWriteSeeker(&RWS{}))), "*main.RWS rws"},
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{makeRWS(), "*main.RWS rws"},
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{map[string]string{"here": "there"}, "map[string]string map[here:there]"},
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{chan bool(nil), "chan bool <nil>"},
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{unsafe.Pointer(uintptr(0)), "unsafe.Pointer <nil>"},
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{(*byte)(nil), "*uint8 <nil>"},
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{io.Writer((*os.File)(nil)), "*os.File <nil>"},
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{(interface{})(io.Writer((*os.File)(nil))), "*os.File <nil>"},
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{fmt.Stringer(Strunger(((*Int)(nil)))), "*main.Int <nil>"},
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}
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type Int int
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func (i Int) String() string { return fmt.Sprintf("Int=%d", i) }
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func (i Int) Strung() {}
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type Strunger interface {
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fmt.Stringer
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Strung()
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}
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// Test correct construction of static non-empty interface values
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var ifaces = [...]struct {
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x fmt.Stringer
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s string
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}{
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{nil, "<nil> <nil> %!s(<nil>)"},
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{Int(3), "main.Int 3 Int=3"},
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{Int(int(Int(4))), "main.Int 4 Int=4"},
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{Strunger(Int(5)), "main.Int 5 Int=5"},
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{makeStringer(), "*main.RWS &main.RWS{} rws"},
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{fmt.Stringer(nil), "<nil> <nil> %!s(<nil>)"},
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{(*RWS)(nil), "*main.RWS (*main.RWS)(nil) rws"},
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}
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// Test correct handling of direct interface values
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var (
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one int = 1
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iptr interface{} = &one
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clos int
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f interface{} = func() { clos++ }
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deep interface{} = [1]struct{ a *[2]byte }{{a: &[2]byte{'z', 'w'}}}
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ch interface{} = make(chan bool, 1)
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)
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func main() {
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var fail bool
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for i, test := range efaces {
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s := fmt.Sprintf("%[1]T %[1]v", test.x)
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if s != test.s {
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fmt.Printf("eface(%d)=%q want %q\n", i, s, test.s)
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fail = true
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}
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}
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for i, test := range ifaces {
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s := fmt.Sprintf("%[1]T %#[1]v %[1]s", test.x)
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if s != test.s {
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fmt.Printf("iface(%d)=%q want %q\n", i, s, test.s)
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fail = true
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}
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}
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if got := *(iptr.(*int)); got != 1 {
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fmt.Printf("bad int ptr %d\n", got)
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fail = true
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}
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f.(func())()
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f.(func())()
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f.(func())()
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if clos != 3 {
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fmt.Printf("bad closure exec %d\n", clos)
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fail = true
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}
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if !reflect.DeepEqual(*(deep.([1]struct{ a *[2]byte })[0].a), [2]byte{'z', 'w'}) {
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fmt.Printf("bad deep directiface\n")
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fail = true
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}
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cc := ch.(chan bool)
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cc <- true
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if got := <-cc; !got {
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fmt.Printf("bad chan\n")
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fail = true
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}
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if fail {
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fmt.Println("BUG")
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os.Exit(1)
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}
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}
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