package-local declarations using keyword "package".

R=r
DELTA=129  (81 added, 0 deleted, 48 changed)
OCL=19283
CL=19291

6 files changed, 116 insertions, 35 deletions

diff --git a/src/cmd/6l/go.c b/src/cmd/6l/go.c
index 4d2f5ec54..e073959de 100644
--- a/src/cmd/6l/go.c
+++ b/src/cmd/6l/go.c
@@ -188,12 +188,16 @@ parsepkgdata(char *file, char **pp, char *ep, int *exportp, char **prefixp, char
 	if(p == ep || strncmp(p, "$$\n", 3) == 0)
 		return 0;
 
-	// [export ]
+	// [export|package ]
 	*exportp = 0;
 	if(p + 7 <= ep && strncmp(p, "export ", 7) == 0) {
 		*exportp = 1;
 		p += 7;
 	}
+	else if(p + 8 <= ep && strncmp(p, "package ", 8) == 0) {
+		*exportp = 2;
+		p += 8;
+	}
 
 	// prefix: (var|type|func|const)
 	prefix = p;
@@ -210,7 +214,7 @@ parsepkgdata(char *file, char **pp, char *ep, int *exportp, char **prefixp, char
 	else if(strncmp(p, "const ", 6) == 0)
 		p += 6;
 	else{
-		fprint(2, "ar: confused in pkg data near <<%.20s>>\n", p);
+		fprint(2, "6l: confused in pkg data near <<%.20s>>\n", p);
 		nerrors++;
 		return -1;
 	}
@@ -283,7 +287,7 @@ parsemethod(char **pp, char *ep, char **methp)
 	while(p < ep && *p != '\n')
 		p++;
 	if(p >= ep) {
-		fprint(2, "ar: lost end of line in method definition\n");
+		fprint(2, "6l: lost end of line in method definition\n");
 		*pp = ep;
 		return -1;
 	}
diff --git a/src/cmd/ar/ar.c b/src/cmd/ar/ar.c
index 513d6af43..056753ac3 100644
--- a/src/cmd/ar/ar.c
+++ b/src/cmd/ar/ar.c
@@ -1445,7 +1445,7 @@ typedef struct Import Import;
 struct Import
 {
 	Import *hash;	// next in hash table
-	int export;	// marked as export?
+	char *export;	// marked as export or package?
 	char *prefix;	// "type", "var", "func", "const"
 	char *name;
 	char *def;
@@ -1476,12 +1476,12 @@ ilookup(char *name)
 }
 
 int parsemethod(char**, char*, char**);
-int parsepkgdata(char**, char*, int*, char**, char**, char**);
+int parsepkgdata(char**, char*, char**, char**, char**, char**);
 
 void
 loadpkgdata(char *data, int len)
 {
-	int export;
+	char *export;
 	char *p, *ep, *prefix, *name, *def;
 	Import *x;
 
@@ -1509,16 +1509,24 @@ loadpkgdata(char *data, int len)
 				errors++;
 			}
 
-			// okay if some .6 say export and others don't.
-			// all it takes is one.
-			if(export)
-				x->export = 1;
+			// okay if some .6 say export/package and others don't.
+			// all it takes is one.  not okay if some say export
+			// and others say package.
+			if(export) {
+				if(x->export == nil)
+					x->export = export;
+				else if(strcmp(x->export, export) != 0) {
+					fprint(2, "ar: conflicting scopes for %s\n", name);
+					fprint(2, "%s:\t%s\n", x->file, x->export);
+					fprint(2, "%s:\t%s\n", file, export);
+				}
+			}
 		}
 	}
 }
 
 int
-parsepkgdata(char **pp, char *ep, int *exportp, char **prefixp, char **namep, char **defp)
+parsepkgdata(char **pp, char *ep, char **exportp, char **prefixp, char **namep, char **defp)
 {
 	char *p, *prefix, *name, *def, *edef, *meth;
 	int n;
@@ -1530,11 +1538,14 @@ parsepkgdata(char **pp, char *ep, int *exportp, char **prefixp, char **namep, ch
 	if(p == ep)
 		return 0;
 
-	// [export ]
+	// [export|package ]
 	*exportp = 0;
 	if(p + 7 <= ep && strncmp(p, "export ", 7) == 0) {
-		*exportp = 1;
+		*exportp = "export";
 		p += 7;
+	} else if(p + 8 <= ep && strncmp(p, "package ", 8) == 0) {
+		*exportp = "package";
+		p += 8;
 	}
 
 	// prefix: (var|type|func|const)
@@ -1672,8 +1683,10 @@ getpkgdef(char **datap, int *lenp)
 	Import **all, *x;
 
 	if(pkgstmt == nil) {
-		*datap = nil;
-		*lenp = 0;
+		// Write out non-empty, parseable __.PKGDEF,
+		// so that import of an empty archive works.
+		*datap = "import\n$$\npackage __emptypackage__\n$$\n";
+		*lenp = strlen(*datap);
 		return;
 	}
 
@@ -1688,7 +1701,7 @@ getpkgdef(char **datap, int *lenp)
 				+ strlen(x->name) + 1
 				+ strlen(x->def) + 1;
 			if(x->export)
-				len += 7;
+				len += strlen(x->export) + 1;
 		}
 	}
 	if(j != nimport) {
@@ -1712,9 +1725,11 @@ getpkgdef(char **datap, int *lenp)
 	p = strappend(p, "\n");
 	for(i=0; i<nimport; i++) {
 		x = all[i];
-		// [export] prefix name def\n
-		if(x->export)
-			p = strappend(p, "export ");
+		// [export|package] prefix name def\n
+		if(x->export) {
+			p = strappend(p, x->export);
+			p = strappend(p, " ");
+		}
 		p = strappend(p, x->prefix);
 		p = strappend(p, " ");
 		p = strappend(p, x->name);
diff --git a/src/cmd/gc/dcl.c b/src/cmd/gc/dcl.c
index ef1ddbc71..ca76bd712 100644
--- a/src/cmd/gc/dcl.c
+++ b/src/cmd/gc/dcl.c
@@ -35,8 +35,8 @@ dodclvar(Node *n, Type *t)
 		t = typ(TFORW);
 
 	addvar(n, t, dclcontext);
-	if(exportadj)
-		exportsym(n->sym);
+	if(dcladj)
+		dcladj(n->sym);
 }
 
 void
@@ -49,8 +49,8 @@ dodclconst(Node *n, Node *e)
 		dodclconst(n, e);
 
 	addconst(n, e, dclcontext);
-	if(exportadj)
-		exportsym(n->sym);
+	if(dcladj)
+		dcladj(n->sym);
 }
 
 /*
@@ -79,8 +79,8 @@ dodcltype(Type *n)
 
 found:
 	n->sym->local = 1;
-	if(exportadj)
-		exportsym(n->sym);
+	if(dcladj)
+		dcladj(n->sym);
 	return n;
 }
 
@@ -226,7 +226,7 @@ Node*
 methodname(Node *n, Type *t)
 {
 	Sym *s;
-	
+
 	s = methodsym(n->sym, t);
 	if(s == S)
 		return n;
@@ -1191,7 +1191,7 @@ embedded(Sym *s)
 {
 	Node *n;
 	char *name;
-	
+
 	// Names sometimes have disambiguation junk
 	// appended after a center dot.  Discard it when
 	// making the name for the embedded struct field.
diff --git a/src/cmd/gc/export.c b/src/cmd/gc/export.c
index 3498aa3df..41d3fc414 100644
--- a/src/cmd/gc/export.c
+++ b/src/cmd/gc/export.c
@@ -28,13 +28,30 @@ exportsym(Sym *s)
 {
 	if(s == S)
 		return;
-	if(s->export != 0)
+	if(s->export != 0) {
+		if(s->export != 1)
+			yyerror("export/package mismatch: %S", s);
 		return;
+	}
 	s->export = 1;
 
 	addexportsym(s);
 }
 
+void
+packagesym(Sym *s)
+{
+	if(s == S)
+		return;
+	if(s->export != 0) {
+		if(s->export != 2)
+			yyerror("export/package mismatch: %S", s);
+		return;
+	}
+	s->export = 2;
+
+	addexportsym(s);
+}
 
 void
 dumpprereq(Type *t)
@@ -67,8 +84,10 @@ dumpexportconst(Sym *s)
 		dumpprereq(t);
 
 	Bprint(bout, "\t");
-	if(s->export != 0)
+	if(s->export == 1)
 		Bprint(bout, "export ");
+	else if(s->export == 2)
+		Bprint(bout, "package ");
 	Bprint(bout, "const %lS ", s);
 	if(t != T)
 		Bprint(bout, "%#T ", t);
@@ -110,8 +129,10 @@ dumpexportvar(Sym *s)
 	dumpprereq(t);
 
 	Bprint(bout, "\t");
-	if(s->export != 0)
+	if(s->export == 1)
 		Bprint(bout, "export ");
+	else if(s->export == 2)
+		Bprint(bout, "package ");
 	if(t->etype == TFUNC)
 		Bprint(bout, "func ");
 	else
@@ -124,8 +145,10 @@ dumpexporttype(Sym *s)
 {
 	dumpprereq(s->otype);
 	Bprint(bout, "\t");
-	if(s->export != 0)
+	if(s->export == 1)
 		Bprint(bout, "export ");
+	else if(s->export == 2)
+		Bprint(bout, "package ");
 	switch (s->otype->etype) {
 	case TFORW:
 	case TFORWSTRUCT:
@@ -290,12 +313,21 @@ pkgtype(char *name, char *pkg)
 	return s->otype;
 }
 
+static int
+mypackage(Node *ss)
+{
+	return strcmp(ss->psym->name, package) == 0;
+}
+
 void
 importconst(int export, Node *ss, Type *t, Val *v)
 {
 	Node *n;
 	Sym *s;
 
+	if(export == 2 && !mypackage(ss))
+		return;
+
 	n = nod(OLITERAL, N, N);
 	n->val = *v;
 	n->type = t;
@@ -307,6 +339,7 @@ importconst(int export, Node *ss, Type *t, Val *v)
 	}
 
 	dodclconst(newname(s), n);
+	s->export = export;
 
 	if(debug['e'])
 		print("import const %S\n", s);
@@ -317,6 +350,9 @@ importvar(int export, Node *ss, Type *t)
 {
 	Sym *s;
 
+	if(export == 2 && !mypackage(ss))
+		return;
+
 	s = importsym(ss, LNAME);
 	if(s->oname != N) {
 		if(eqtype(t, s->oname->type, 0))
@@ -326,6 +362,7 @@ importvar(int export, Node *ss, Type *t)
 	}
 	checkwidth(t);
 	addvar(newname(s), t, PEXTERN);
+	s->export = export;
 
 	if(debug['e'])
 		print("import var %S %lT\n", s, t);
@@ -352,6 +389,14 @@ importtype(int export, Node *ss, Type *t)
 	s->otype->sym = s;
 	checkwidth(s->otype);
 
+	// If type name should not be visible to importers,
+	// hide it by setting the lexical type to name.
+	// This will make references in the ordinary program
+	// (but not the import sections) look at s->oname,
+	// which is nil, as for an undefined name.
+	if(export == 0 || (export == 2 && !mypackage(ss)))
+		s->lexical = LNAME;
+
 	if(debug['e'])
 		print("import type %S %lT\n", s, t);
 }
diff --git a/src/cmd/gc/go.h b/src/cmd/gc/go.h
index c76adf692..cc842bc94 100644
--- a/src/cmd/gc/go.h
+++ b/src/cmd/gc/go.h
@@ -41,7 +41,7 @@ enum
 	ASTRING,
 	APTR,
 	AINTER,
-	
+
 	BADWIDTH	= -1000000000
 };
 
@@ -438,7 +438,7 @@ EXTERN	Sym*	pkgimportname;	// package name from imported package
 EXTERN	int	tptr;		// either TPTR32 or TPTR64
 extern	char*	sysimport;
 EXTERN	char*	filename;	// name to uniqify names
-EXTERN	int	exportadj;	// declaration is being exported
+EXTERN	void	(*dcladj)(Sym*);	// declaration is being exported/packaged
 
 EXTERN	Type*	types[NTYPE];
 EXTERN	uchar	simtype[NTYPE];
@@ -710,6 +710,7 @@ Node*	embedded(Sym*);
  */
 void	renamepkg(Node*);
 void	exportsym(Sym*);
+void	packagesym(Sym*);
 void	dumpe(Sym*);
 void	dumpexport(void);
 void	dumpexporttype(Sym*);
diff --git a/src/cmd/gc/go.y b/src/cmd/gc/go.y
index 861f4fb29..077231810 100644
--- a/src/cmd/gc/go.y
+++ b/src/cmd/gc/go.y
@@ -193,10 +193,16 @@ xdcl:
 	{
 		$$ = N;
 	}
-|	LEXPORT { exportadj = 1; stksize = initstksize; } common_dcl
+|	LEXPORT { dcladj = exportsym; stksize = initstksize; } common_dcl
 	{
 		$$ = $3;
-		exportadj = 0;
+		dcladj = 0;
+		initstksize = stksize;
+	}
+|	LPACKAGE { dcladj = packagesym; stksize = initstksize; } common_dcl
+	{
+		$$ = $3;
+		dcladj = 0;
 		initstksize = stksize;
 	}
 |	LEXPORT '(' export_list_r ')'
@@ -209,6 +215,12 @@ xdcl:
 			exportsym($2->nname->sym);
 		$$ = N;
 	}
+|	LPACKAGE xfndcl
+	{
+		if($2 != N && $2->nname != N)
+			packagesym($2->nname->sym);
+		$$ = N;
+	}
 |	';'
 	{
 		$$ = N;
@@ -1773,6 +1785,10 @@ oexport:
 	{
 		$$ = 1;
 	}
+|	LPACKAGE
+	{
+		$$ = 2;
+	}
 
 oliteral:
 	{