From 674458e1c43935acbab3abe50617ed8f3368dcb9 Mon Sep 17 00:00:00 2001
From: Russ Cox <rsc@golang.org>
Date: Mon, 1 Feb 2010 23:05:15 -0800
Subject: [PATCH] gc: bug246

R=ken2
CC=golang-dev
https://golang.org/cl/198057
---
 src/cmd/gc/align.c                 |  5 +++++
 src/cmd/gc/const.c                 | 11 ++++++++++-
 src/cmd/gc/go.h                    |  1 +
 src/cmd/gc/walk.c                  |  2 +-
 test/{bugs => fixedbugs}/bug246.go | 12 ++++++++----
 test/golden.out                    |  5 -----
 6 files changed, 25 insertions(+), 11 deletions(-)
 rename test/{bugs => fixedbugs}/bug246.go (51%)

diff --git a/src/cmd/gc/align.c b/src/cmd/gc/align.c
index 7a27a040c9f..dfb9f9e8921 100644
--- a/src/cmd/gc/align.c
+++ b/src/cmd/gc/align.c
@@ -410,6 +410,7 @@ typeinit(void)
 			okforarith[i] = 1;
 			okforadd[i] = 1;
 			okforand[i] = 1;
+			okforconst[i] = 1;
 			issimple[i] = 1;
 			minintval[i] = mal(sizeof(*minintval[i]));
 			maxintval[i] = mal(sizeof(*maxintval[i]));
@@ -419,6 +420,7 @@ typeinit(void)
 			okforcmp[i] = 1;
 			okforadd[i] = 1;
 			okforarith[i] = 1;
+			okforconst[i] = 1;
 			issimple[i] = 1;
 			minfltval[i] = mal(sizeof(*minfltval[i]));
 			maxfltval[i] = mal(sizeof(*maxfltval[i]));
@@ -434,6 +436,9 @@ typeinit(void)
 	okforcap[TARRAY] = 1;
 	okforcap[TCHAN] = 1;
 
+	okforconst[TBOOL] = 1;
+	okforconst[TSTRING] = 1;
+
 	okforlen[TARRAY] = 1;
 	okforlen[TCHAN] = 1;
 	okforlen[TMAP] = 1;
diff --git a/src/cmd/gc/const.c b/src/cmd/gc/const.c
index d7d6e350377..a78c122fecb 100644
--- a/src/cmd/gc/const.c
+++ b/src/cmd/gc/const.c
@@ -93,6 +93,9 @@ convlit1(Node **np, Type *t, int explicit)
 		}
 		return;
 	case OLITERAL:
+		// target is invalid type for a constant?  leave alone.
+		if(!okforconst[t->etype] && n->type->etype != TNIL)
+			return;
 		break;
 	case OLSH:
 	case ORSH:
@@ -105,6 +108,7 @@ convlit1(Node **np, Type *t, int explicit)
 		n->type = t;
 		return;
 	}
+
 	// avoided repeated calculations, errors
 	if(cvttype(n->type, t) == 1) {
 		n->type = t;
@@ -345,7 +349,6 @@ evconst(Node *n)
 	case OANDNOT:
 	case OARRAYBYTESTR:
 	case OCOM:
-	case OCONV:
 	case ODIV:
 	case OEQ:
 	case OGE:
@@ -365,6 +368,12 @@ evconst(Node *n)
 	case OSUB:
 	case OXOR:
 		break;
+	case OCONV:
+		if(n->type == T)
+			return;
+		if(!okforconst[n->type->etype] && n->type->etype != TNIL)
+			return;
+		break;
 	}
 
 	nl = n->left;
diff --git a/src/cmd/gc/go.h b/src/cmd/gc/go.h
index 16cf87f0c22..98a15970118 100644
--- a/src/cmd/gc/go.h
+++ b/src/cmd/gc/go.h
@@ -680,6 +680,7 @@ EXTERN	uchar	okforbool[NTYPE];
 EXTERN	uchar	okforcap[NTYPE];
 EXTERN	uchar	okforlen[NTYPE];
 EXTERN	uchar	okforarith[NTYPE];
+EXTERN	uchar	okforconst[NTYPE];
 EXTERN	uchar*	okfor[OEND];
 EXTERN	uchar	iscmp[OEND];
 
diff --git a/src/cmd/gc/walk.c b/src/cmd/gc/walk.c
index f560d5be27a..ffdd17a95da 100644
--- a/src/cmd/gc/walk.c
+++ b/src/cmd/gc/walk.c
@@ -182,7 +182,7 @@ walkdef(Node *n)
 		t = n->type;
 		if(t != T) {
 			convlit(&e, t);
-			if(!isint[t->etype] && !isfloat[t->etype] && t->etype != TSTRING && t->etype != TBOOL)
+			if(!okforconst[t->etype])
 				yyerror("invalid constant type %T", t);
 		}
 		n->val = e->val;
diff --git a/test/bugs/bug246.go b/test/fixedbugs/bug246.go
similarity index 51%
rename from test/bugs/bug246.go
rename to test/fixedbugs/bug246.go
index e46cdfd048f..1c4dc0d5370 100644
--- a/test/bugs/bug246.go
+++ b/test/fixedbugs/bug246.go
@@ -1,4 +1,4 @@
-// $G $D/$F.go || echo BUG: bug246
+// $G $D/$F.go && $L $F.$A && ./$A.out || echo BUG: bug246
 
 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
@@ -10,9 +10,13 @@ import "unsafe"
 
 func main() {
 	// works
-	addr := uintptr(0)
-	_ = (*int)(unsafe.Pointer(addr))
+	addr := uintptr(0x234)
+	x1 := (*int)(unsafe.Pointer(addr))
 
 	// fails
-	_ = (*int)(unsafe.Pointer(uintptr(0)))
+	x2 := (*int)(unsafe.Pointer(uintptr(0x234)))
+	
+	if x1 != x2 {
+		panicln("mismatch", x1, x2)
+	}
 }
diff --git a/test/golden.out b/test/golden.out
index 63d179cba54..cf2297e1a73 100644
--- a/test/golden.out
+++ b/test/golden.out
@@ -150,8 +150,3 @@ throw: interface conversion
 panic PC=xxx
 
 == bugs/
-
-=========== bugs/bug246.go
-bugs/bug246.go:17: cannot convert 0 to type unsafe.Pointer
-bugs/bug246.go:17: cannot convert 0 (type uintptr) to type *int in conversion
-BUG: bug246