gc: fix init of packages named main

This change removes the special case which existed
for handling the initalization of the main package,
so that other modules named 'main' get properly
initialized when imported.

Note that gotest of main packages will break in most
cases without this.

R=rsc
CC=golang-dev
https://golang.org/cl/4190050

src/cmd/gc/export.c

@@ -51,6 +51,12 @@ exportname(char *s)
 	return isupperrune(r);
 }
 
+static int
+initname(char *s)
+{
+	return strcmp(s, "init") == 0;
+}
+
 void
 autoexport(Node *n, int ctxt)
 {
@@ -60,7 +66,7 @@ autoexport(Node *n, int ctxt)
 		return;
 	if(n->ntype && n->ntype->op == OTFUNC && n->ntype->left)	// method
 		return;
-	if(exportname(n->sym->name) || strcmp(n->sym->name, "init") == 0)
+	if(exportname(n->sym->name) || initname(n->sym->name))
 		exportsym(n);
 	else
 		packagesym(n);
@@ -304,7 +310,7 @@ importsym(Sym *s, int op)
 
 	// mark the symbol so it is not reexported
 	if(s->def == N) {
-		if(exportname(s->name))
+		if(exportname(s->name) || initname(s->name))
 			s->flags |= SymExport;
 		else
 			s->flags |= SymPackage;	// package scope
@@ -374,7 +380,7 @@ importvar(Sym *s, Type *t, int ctxt)
 {
 	Node *n;
 
-	if(!exportname(s->name) && !mypackage(s))
+	if(!exportname(s->name) && !initname(s->name) && !mypackage(s))
 		return;
 
 	importsym(s, ONAME);

src/cmd/gc/init.c

@@ -30,19 +30,19 @@ renameinit(Node *n)
 
 /*
  * hand-craft the following initialization code
- *	var initdone·<file> uint8 			(1)
- *	func	Init·<file>()				(2)
- *		if initdone·<file> != 0 {		(3)
- *			if initdone·<file> == 2		(4)
+ *	var initdone· uint8 				(1)
+ *	func init()					(2)
+ *		if initdone· != 0 {			(3)
+ *			if initdone· == 2		(4)
  *				return
  *			throw();			(5)
  *		}
- *		initdone.<file> = 1;			(6)
+ *		initdone· = 1;				(6)
  *		// over all matching imported symbols
- *			<pkg>.init·<file>()		(7)
+ *			<pkg>.init()			(7)
  *		{ <init stmts> }			(8)
- *		init·<file>()	// if any		(9)
- *		initdone.<file> = 2;			(10)
+ *		init·<n>() // if any			(9)
+ *		initdone· = 2;				(10)
  *		return					(11)
  *	}
  */
@@ -79,7 +79,7 @@ anyinit(NodeList *n)
 	// are there any imported init functions
 	for(h=0; h<NHASH; h++)
 	for(s = hash[h]; s != S; s = s->link) {
-		if(s->name[0] != 'I' || strncmp(s->name, "Init·", 6) != 0)
+		if(s->name[0] != 'i' || strcmp(s->name, "init") != 0)
 			continue;
 		if(s->def == N)
 			continue;
@@ -118,12 +118,7 @@ fninit(NodeList *n)
 
 	// (2)
 	maxarg = 0;
-	snprint(namebuf, sizeof(namebuf), "Init·");
-
-	// this is a botch since we need a known name to
-	// call the top level init function out of rt0
-	if(strcmp(localpkg->name, "main") == 0)
-		snprint(namebuf, sizeof(namebuf), "init");
+	snprint(namebuf, sizeof(namebuf), "init");
 
 	fn = nod(ODCLFUNC, N, N);
 	initsym = lookup(namebuf);
@@ -154,7 +149,7 @@ fninit(NodeList *n)
 	// (7)
 	for(h=0; h<NHASH; h++)
 	for(s = hash[h]; s != S; s = s->link) {
-		if(s->name[0] != 'I' || strncmp(s->name, "Init·", 6) != 0)
+		if(s->name[0] != 'i' || strcmp(s->name, "init") != 0)
 			continue;
 		if(s->def == N)
 			continue;

src/cmd/gc/subr.c

@@ -2268,7 +2268,7 @@ syslook(char *name, int copy)
 
 	s = pkglookup(name, runtimepkg);
 	if(s == S || s->def == N)
-		fatal("looksys: cant find runtime.%s", name);
+		fatal("syslook: can't find runtime.%s", name);
 
 	if(!copy)
 		return s->def;

test/init.go

@@ -0,0 +1,18 @@
+// errchk $G -e $D/$F.go
+
+// Copyright 2011 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.
+
+package main
+
+import "runtime"
+
+func init() {
+}
+
+func main() {
+	init()         // ERROR "undefined: init"
+	runtime.init() // ERROR "unexported.*runtime\.init"
+	var _ = init   // ERROR "undefined: init"
+}