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go/test/sinit.go
Keith Randall 4a1a783dda cmd/compile: fix static initializer
staticcopy of a struct or array should recursively call itself, not
staticassign.

This fixes an issue where a struct with a slice in it is copied during
static initialization. In this case, the backing array for the slice
is duplicated, and each copy of the slice refers to a different
backing array, which is incorrect.  That issue has existed since at
least Go 1.2.

I'm not sure why this was never noticed. It seems like a pretty
obvious bug if anyone modifies the resulting slice.

In any case, we started to notice when the optimization in CL 140301
landed.  Here is basically what happens in issue29013b.go:
1) The error above happens, so we get two backing stores for what
   should be the same slice.
2) The code for initializing those backing stores is reused.
   But not duplicated: they are the same Node structure.
3) The order pass allocates temporaries for the map operations.
   For the first instance, things work fine and two temporaries are
   allocated and stored in the OKEY nodes. For the second instance,
   the order pass decides new temporaries aren't needed, because
   the OKEY nodes already have temporaries in them.
   But the order pass also puts a VARKILL of the temporaries between
   the two instance initializations.
4) In this state, the code is technically incorrect. But before
   CL 140301 it happens to work because the temporaries are still
   correctly initialized when they are used for the second time. But then...
5) The new CL 140301 sees the VARKILLs and decides to reuse the
   temporary for instance 1 map 2 to initialize the instance 2 map 1
   map. Because the keys aren't re-initialized, instance 2 map 1
   gets the wrong key inserted into it.

Fixes #29013

Change-Id: I840ce1b297d119caa706acd90e1517a5e47e9848
Reviewed-on: https://go-review.googlesource.com/c/152081
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2018-12-03 16:48:21 +00:00

286 lines
5.8 KiB
Go

// skip
// Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Test that many initializations can be done at link time and
// generate no executable init functions.
// This test is run by sinit_run.go.
package p
import "unsafe"
// Should be no init func in the assembly.
// All these initializations should be done at link time.
type S struct{ a, b, c int }
type SS struct{ aa, bb, cc S }
type SA struct{ a, b, c [3]int }
type SC struct{ a, b, c []int }
var (
zero = 2
one = 1
pi = 3.14
slice = []byte{1, 2, 3}
sliceInt = []int{1, 2, 3}
hello = "hello, world"
bytes = []byte("hello, world")
four, five = 4, 5
x, y = 0.1, "hello"
nilslice []byte = nil
nilmap map[string]int = nil
nilfunc func() = nil
nilchan chan int = nil
nilptr *byte = nil
)
var a = [3]int{1001, 1002, 1003}
var s = S{1101, 1102, 1103}
var c = []int{1201, 1202, 1203}
var aa = [3][3]int{[3]int{2001, 2002, 2003}, [3]int{2004, 2005, 2006}, [3]int{2007, 2008, 2009}}
var as = [3]S{S{2101, 2102, 2103}, S{2104, 2105, 2106}, S{2107, 2108, 2109}}
var sa = SA{[3]int{3001, 3002, 3003}, [3]int{3004, 3005, 3006}, [3]int{3007, 3008, 3009}}
var ss = SS{S{3101, 3102, 3103}, S{3104, 3105, 3106}, S{3107, 3108, 3109}}
var ca = [][3]int{[3]int{4001, 4002, 4003}, [3]int{4004, 4005, 4006}, [3]int{4007, 4008, 4009}}
var cs = []S{S{4101, 4102, 4103}, S{4104, 4105, 4106}, S{4107, 4108, 4109}}
var answers = [...]int{
// s
1101, 1102, 1103,
// ss
3101, 3102, 3103,
3104, 3105, 3106,
3107, 3108, 3109,
// [0]
1001, 1201, 1301,
2101, 2102, 2103,
4101, 4102, 4103,
5101, 5102, 5103,
3001, 3004, 3007,
3201, 3204, 3207,
3301, 3304, 3307,
// [0][j]
2001, 2201, 2301, 4001, 4201, 4301, 5001, 5201, 5301,
2002, 2202, 2302, 4002, 4202, 4302, 5002, 5202, 5302,
2003, 2203, 2303, 4003, 4203, 4303, 5003, 5203, 5303,
// [1]
1002, 1202, 1302,
2104, 2105, 2106,
4104, 4105, 4106,
5104, 5105, 5106,
3002, 3005, 3008,
3202, 3205, 3208,
3302, 3305, 3308,
// [1][j]
2004, 2204, 2304, 4004, 4204, 4304, 5004, 5204, 5304,
2005, 2205, 2305, 4005, 4205, 4305, 5005, 5205, 5305,
2006, 2206, 2306, 4006, 4206, 4306, 5006, 5206, 5306,
// [2]
1003, 1203, 1303,
2107, 2108, 2109,
4107, 4108, 4109,
5107, 5108, 5109,
3003, 3006, 3009,
3203, 3206, 3209,
3303, 3306, 3309,
// [2][j]
2007, 2207, 2307, 4007, 4207, 4307, 5007, 5207, 5307,
2008, 2208, 2308, 4008, 4208, 4308, 5008, 5208, 5308,
2009, 2209, 2309, 4009, 4209, 4309, 5009, 5209, 5309,
}
var (
copy_zero = zero
copy_one = one
copy_pi = pi
copy_slice = slice
copy_sliceInt = sliceInt
copy_hello = hello
// Could be handled without an initialization function, but
// requires special handling for "a = []byte("..."); b = a"
// which is not a likely case.
// copy_bytes = bytes
// https://codereview.appspot.com/171840043 is one approach to
// make this special case work.
copy_four, copy_five = four, five
copy_x, copy_y = x, y
copy_nilslice = nilslice
copy_nilmap = nilmap
copy_nilfunc = nilfunc
copy_nilchan = nilchan
copy_nilptr = nilptr
)
var copy_a = a
var copy_s = s
var copy_c = c
var copy_aa = aa
var copy_as = as
var copy_sa = sa
var copy_ss = ss
var copy_ca = ca
var copy_cs = cs
var copy_answers = answers
var bx bool
var b0 = false
var b1 = true
var fx float32
var f0 = float32(0)
var f1 = float32(1)
var gx float64
var g0 = float64(0)
var g1 = float64(1)
var ix int
var i0 = 0
var i1 = 1
var jx uint
var j0 = uint(0)
var j1 = uint(1)
var cx complex64
var c0 = complex64(0)
var c1 = complex64(1)
var dx complex128
var d0 = complex128(0)
var d1 = complex128(1)
var sx []int
var s0 = []int{0, 0, 0}
var s1 = []int{1, 2, 3}
func fi() int { return 1 }
var ax [10]int
var a0 = [10]int{0, 0, 0}
var a1 = [10]int{1, 2, 3, 4}
type T struct{ X, Y int }
var tx T
var t0 = T{}
var t0a = T{0, 0}
var t0b = T{X: 0}
var t1 = T{X: 1, Y: 2}
var t1a = T{3, 4}
var psx *[]int
var ps0 = &[]int{0, 0, 0}
var ps1 = &[]int{1, 2, 3}
var pax *[10]int
var pa0 = &[10]int{0, 0, 0}
var pa1 = &[10]int{1, 2, 3}
var ptx *T
var pt0 = &T{}
var pt0a = &T{0, 0}
var pt0b = &T{X: 0}
var pt1 = &T{X: 1, Y: 2}
var pt1a = &T{3, 4}
// The checks similar to
// var copy_bx = bx
// are commented out. The compiler no longer statically initializes them.
// See issue 7665 and https://codereview.appspot.com/93200044.
// If https://codereview.appspot.com/169040043 is submitted, and this
// test is changed to pass -complete to the compiler, then we can
// uncomment the copy lines again.
// var copy_bx = bx
var copy_b0 = b0
var copy_b1 = b1
// var copy_fx = fx
var copy_f0 = f0
var copy_f1 = f1
// var copy_gx = gx
var copy_g0 = g0
var copy_g1 = g1
// var copy_ix = ix
var copy_i0 = i0
var copy_i1 = i1
// var copy_jx = jx
var copy_j0 = j0
var copy_j1 = j1
// var copy_cx = cx
var copy_c0 = c0
var copy_c1 = c1
// var copy_dx = dx
var copy_d0 = d0
var copy_d1 = d1
// var copy_sx = sx
var copy_s0 = s0
var copy_s1 = s1
// var copy_ax = ax
var copy_a0 = a0
var copy_a1 = a1
// var copy_tx = tx
var copy_t0 = t0
var copy_t0a = t0a
var copy_t0b = t0b
var copy_t1 = t1
var copy_t1a = t1a
// var copy_psx = psx
var copy_ps0 = ps0
var copy_ps1 = ps1
// var copy_pax = pax
var copy_pa0 = pa0
var copy_pa1 = pa1
// var copy_ptx = ptx
var copy_pt0 = pt0
var copy_pt0a = pt0a
var copy_pt0b = pt0b
var copy_pt1 = pt1
var copy_pt1a = pt1a
var _ interface{} = 1
type T1 int
func (t *T1) M() {}
type Mer interface {
M()
}
var _ Mer = (*T1)(nil)
var Byte byte
var PtrByte unsafe.Pointer = unsafe.Pointer(&Byte)