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cmd/compile: internal compiler error: have Val #12686

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rasky opened this issue Sep 18, 2015 · 5 comments
Closed

cmd/compile: internal compiler error: have Val #12686

rasky opened this issue Sep 18, 2015 · 5 comments
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Go1.5.2

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@rasky
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rasky commented Sep 18, 2015

http://play.golang.org/p/kn1aiXuG0l

package main

import "fmt"

func Crash(used int) {
    data := []byte{(1 << (uint(used) & 7)) - 1}
    fmt.Println(data)
}
have Val [0xc82019f170]
.   SUB l(6) tc(1) byte
.   .   LSH l(6) tc(1) byte
.   .   .   LITERAL-1 l(6) tc(1) byte
.   .   .   AND l(6) tc(1) uint
.   .   .   .   CONV l(6) tc(1) uint
.   .   .   .   .   NAME-main.used u(1) a(true) g(1) l(5) x(0+0) class(PPARAM) f(1) ld(1) tc(1) used(true) int
.   .   .   .   LITERAL-7 l(6) tc(1) uint
.   .   LITERAL-1 l(6) tc(1) byte
prog.go:8: internal compiler error: have Val
panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xb code=0x1 addr=0x0 pc=0x5d3680]

goroutine 1 [running]:
cmd/compile/internal/gc.hcrash()
    /usr/local/go/src/cmd/compile/internal/gc/subr.go:105 +0x50
cmd/compile/internal/gc.Fatal(0x81ec90, 0x8, 0x0, 0x0, 0x0)
    /usr/local/go/src/cmd/compile/internal/gc/subr.go:198 +0x2b1
cmd/compile/internal/gc.(*Node).SetOpt(0xc82019f170, 0x77b9c0, 0xc820195530)
    /usr/local/go/src/cmd/compile/internal/gc/syntax.go:107 +0x97
cmd/compile/internal/gc.(*EscState).nodeEscState(0xc8201a6000, 0xc82019f170, 0x77b9c0)
    /usr/local/go/src/cmd/compile/internal/gc/esc.go:330 +0x1f6
cmd/compile/internal/gc.escwalk(0xc8201a6000, 0xc82019ffff, 0xc82019f290, 0xc82019f170)
    /usr/local/go/src/cmd/compile/internal/gc/esc.go:1590 +0x6d
cmd/compile/internal/gc.escwalk(0xc8201a6000, 0xc820190000, 0xc82019f290, 0xc82019ecf0)
    /usr/local/go/src/cmd/compile/internal/gc/esc.go:1710 +0x288c
cmd/compile/internal/gc.escflood(0xc8201a6000, 0xc82019f290)
    /usr/local/go/src/cmd/compile/internal/gc/esc.go:1575 +0x35f
cmd/compile/internal/gc.escAnalyze(0xc82017f680, 0xc820195200)
    /usr/local/go/src/cmd/compile/internal/gc/esc.go:456 +0x214
cmd/compile/internal/gc.(*bottomUpVisitor).visit(0xc820089ab0, 0xc82019e900, 0xc8201952c0)
    /usr/local/go/src/cmd/compile/internal/gc/esc.go:107 +0x297
cmd/compile/internal/gc.visitBottomUp(0xc82017f4a0, 0x89b080)
    /usr/local/go/src/cmd/compile/internal/gc/esc.go:62 +0xb0
cmd/compile/internal/gc.escapes(0xc82017f4a0)
    /usr/local/go/src/cmd/compile/internal/gc/esc.go:187 +0x2d
cmd/compile/internal/gc.Main()
    /usr/local/go/src/cmd/compile/internal/gc/lex.go:456 +0x1e65
cmd/compile/internal/amd64.Main()
    /usr/local/go/src/cmd/compile/internal/amd64/galign.go:127 +0x58d
main.main()
    /usr/local/go/src/cmd/compile/main.go:26 +0x189

Program exited.
@ianlancetaylor ianlancetaylor added this to the Go1.5.2 milestone Sep 19, 2015
@ianlancetaylor ianlancetaylor changed the title Go 1.5: internal compiler error: have Val cmd/compile: internal compiler error: have Val Sep 19, 2015
@ianlancetaylor
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This is a compiler crash on valid code.

@minux
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minux commented Sep 19, 2015 via email

@mwhudson
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A slightly smaller test case is:

package foo

func Crash(a uint) uint {
    d := []uint{1 << a}
    return d[0]
}

The call to SetVal that makes the call to SetOpt explode later is from defaultlit. I don't understand what this is about at all :-) but it is setting the Val to nil; maybe setting Val to nil should not "count" when it comes to the checks SetOpt does?

@gopherbot
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CL https://golang.org/cl/17031 mentions this issue.

@rsc rsc closed this as completed in 918a264 Nov 18, 2015
@gopherbot
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CL https://golang.org/cl/17124 mentions this issue.

rsc added a commit that referenced this issue Nov 23, 2015
@rsc
[release-branch.go1.5] cmd/compile: fix Val vs Opt collision
29a22ab 
Fixes #12686.

Change-Id: I7a9f49dbd1f60b1d0240de57787753b425f9548c
Reviewed-on: https://go-review.googlesource.com/17031
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-on: https://go-review.googlesource.com/17124
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