From 3443656bce7e91d243118091f5de1eb448d66dbf Mon Sep 17 00:00:00 2001
From: Russ Cox <rsc@golang.org>
Date: Thu, 27 Aug 2009 11:16:34 -0700
Subject: [PATCH] clean up ideal handling; reject attempts to write type
 descriptors for ideal types

R=ken
OCL=33958
CL=33958
---
 src/cmd/gc/const.c   | 40 +++++++++++-----------------------------
 src/cmd/gc/go.h      |  1 +
 src/cmd/gc/reflect.c | 13 +++++++++++--
 src/cmd/gc/subr.c    | 10 ++++++++++
 4 files changed, 33 insertions(+), 31 deletions(-)

diff --git a/src/cmd/gc/const.c b/src/cmd/gc/const.c
index 1433eb9ba5..59bd9a3887 100644
--- a/src/cmd/gc/const.c
+++ b/src/cmd/gc/const.c
@@ -66,18 +66,13 @@ convlit(Node **np, Type *t)
 void
 convlit1(Node **np, Type *t, int explicit)
 {
-	int et, ct;
+	int ct, et;
 	Node *n, *nn;
 
 	n = *np;
-	if(n == N || t == T || n->type == T)
+	if(n == N || t == T || n->type == T || isideal(t) || eqtype(t, n->type))
 		return;
-	et = t->etype;
-	if(et == TIDEAL || et == TNIL)
-		return;
-	if(eqtype(t, n->type))
-		return;
-	if(!explicit && n->type->etype != TIDEAL && n->type != idealstring && n->type->etype != TNIL)
+	if(!explicit && !isideal(n->type))
 		return;
 
 //dump("convlit1", n);
@@ -120,6 +115,7 @@ convlit1(Node **np, Type *t, int explicit)
 	if(ct < 0)
 		goto bad;
 
+	et = t->etype;
 	if(et == TINTER) {
 		if(ct == CTNIL && n->type == types[TNIL]) {
 			n->type = t;
@@ -129,21 +125,6 @@ convlit1(Node **np, Type *t, int explicit)
 		return;
 	}
 
-	// if already has non-ideal type, cannot change implicitly
-	if(!explicit) {
-		switch(n->type->etype) {
-		case TIDEAL:
-		case TNIL:
-			break;
-		case TSTRING:
-			if(n->type == idealstring)
-				break;
-			// fall through
-		default:
-			goto bad;
-		}
-	}
-
 	switch(ct) {
 	default:
 		goto bad;
@@ -203,7 +184,7 @@ convlit1(Node **np, Type *t, int explicit)
 	return;
 
 bad:
-	if(n->type->etype == TIDEAL) {
+	if(isideal(n->type)) {
 		defaultlit(&n, T);
 		*np = n;
 	}
@@ -720,9 +701,7 @@ defaultlit(Node **np, Type *t)
 	Node *n, *nn;
 
 	n = *np;
-	if(n == N)
-		return;
-	if(n->type == T || (n->type->etype != TIDEAL && n->type->etype != TNIL))
+	if(n == N || !isideal(n->type))
 		return;
 
 	switch(n->op) {
@@ -749,8 +728,7 @@ defaultlit(Node **np, Type *t)
 		return;
 	}
 
-	lno = lineno;
-	lineno = n->lineno;
+	lno = setlineno(n);
 	switch(n->val.ctype) {
 	default:
 		if(t != T) {
@@ -763,6 +741,10 @@ defaultlit(Node **np, Type *t)
 			n->type = T;
 			break;
 		}
+		if(n->val.ctype == CTSTR) {
+			n->type = types[TSTRING];
+			break;
+		}
 		yyerror("defaultlit: unknown literal: %#N", n);
 		break;
 	case CTINT:
diff --git a/src/cmd/gc/go.h b/src/cmd/gc/go.h
index f7d6f83c97..bcbc5f84c8 100644
--- a/src/cmd/gc/go.h
+++ b/src/cmd/gc/go.h
@@ -805,6 +805,7 @@ int	isslice(Type*);
 int	isinter(Type*);
 int	isnilinter(Type*);
 int	isddd(Type*);
+int	isideal(Type*);
 Type*	maptype(Type*, Type*);
 Type*	methtype(Type*);
 Node*	typename(Type*);
diff --git a/src/cmd/gc/reflect.c b/src/cmd/gc/reflect.c
index 597b6a6a34..c82875ca89 100644
--- a/src/cmd/gc/reflect.c
+++ b/src/cmd/gc/reflect.c
@@ -320,7 +320,7 @@ dextratype(Type *t)
 		else
 			ot = duintptr(s, ot, 0);
 	}
-	ggloblsym(s, ot, 1);
+	ggloblsym(s, ot, 0);
 
 	return s;
 }
@@ -480,6 +480,10 @@ dtypesym(Type *t)
 	Sym *s, *s1, *s2;
 	Sig *a, *m;
 	Type *t1;
+	Sym *tsym;
+
+	if(t->etype == TNIL || t->etype == TIDEAL || t == idealstring)
+		fatal("dtypesym ideal %T", t);
 
 	s = typesym(t);
 	if(s->flags & SymSiggen)
@@ -492,6 +496,11 @@ dtypesym(Type *t)
 	t1 = T;
 	if(isptr[t->etype])
 		t1 = t->type;
+	tsym = S;
+	if(t1)
+		tsym = t1->sym;
+	else
+		tsym = t->sym;
 
 	if(strcmp(package, "runtime") == 0) {
 		if(t == types[t->etype])
@@ -639,7 +648,7 @@ ok:
 		break;
 	}
 
-	ggloblsym(s, ot, 1);
+	ggloblsym(s, ot, tsym == nil);
 	return s;
 }
 
diff --git a/src/cmd/gc/subr.c b/src/cmd/gc/subr.c
index 3c4aaf2fee..052be2a844 100644
--- a/src/cmd/gc/subr.c
+++ b/src/cmd/gc/subr.c
@@ -1468,6 +1468,16 @@ isddd(Type *t)
 	return 0;
 }
 
+int
+isideal(Type *t)
+{
+	if(t == T)
+		return 0;
+	if(t == idealstring)
+		return 1;
+	return t->etype == TNIL || t->etype == TIDEAL;
+}
+
 /*
  * given receiver of type t (t == r or t == *r)
  * return type to hang methods off (r).
-- 
2.48.1