From 066ac428cdcb0b220a8a58f31c884d054cecd118 Mon Sep 17 00:00:00 2001 From: Michael Hudson-Doyle Date: Fri, 10 Feb 2017 13:08:13 +1300 Subject: [PATCH] reflect: clear ptrToThis in Ptr when allocating result on heap Otherwise, calling PtrTo on the result will fail. Fixes #19003 Change-Id: I8d7d1981a5d0417d5aee52740469d71e90734963 Reviewed-on: https://go-review.googlesource.com/36731 Run-TryBot: Michael Hudson-Doyle TryBot-Result: Gobot Gobot Reviewed-by: Ian Lance Taylor Reviewed-by: Russ Cox --- src/reflect/all_test.go | 15 ++++++++++----- src/reflect/type.go | 1 + 2 files changed, 11 insertions(+), 5 deletions(-) diff --git a/src/reflect/all_test.go b/src/reflect/all_test.go index 0be306dc54..0b81c28a22 100644 --- a/src/reflect/all_test.go +++ b/src/reflect/all_test.go @@ -2478,17 +2478,24 @@ func TestNumMethodOnDDD(t *testing.T) { } func TestPtrTo(t *testing.T) { + // This block of code means that the ptrToThis field of the + // reflect data for *unsafe.Pointer is non zero, see + // https://golang.org/issue/19003 + var x unsafe.Pointer + var y = &x + var z = &y + var i int - typ := TypeOf(i) + typ := TypeOf(z) for i = 0; i < 100; i++ { typ = PtrTo(typ) } for i = 0; i < 100; i++ { typ = typ.Elem() } - if typ != TypeOf(i) { - t.Errorf("after 100 PtrTo and Elem, have %s, want %s", typ, TypeOf(i)) + if typ != TypeOf(z) { + t.Errorf("after 100 PtrTo and Elem, have %s, want %s", typ, TypeOf(z)) } } @@ -6053,7 +6060,6 @@ func TestUnaddressableField(t *testing.T) { }) } - type Tint int type Tint2 = Tint @@ -6086,4 +6092,3 @@ func TestAliasNames(t *testing.T) { t.Errorf("Talias2 print:\nhave: %s\nwant: %s", out, want) } } - diff --git a/src/reflect/type.go b/src/reflect/type.go index fbfda3a363..40859093be 100644 --- a/src/reflect/type.go +++ b/src/reflect/type.go @@ -1463,6 +1463,7 @@ func (t *rtype) ptrTo() *rtype { pp := *prototype pp.str = resolveReflectName(newName(s, "", "", false)) + pp.ptrToThis = 0 // For the type structures linked into the binary, the // compiler provides a good hash of the string.