first attempt at real FFI support.

in a .6 file, an export line

	//ffi T localfib remotefib remote.so

means the dynamic linker should initialize
localfib, always a pointer, to the address of
remotefib, either text (T) or data (D) after
loading remote.so.

the C compiler will generate an export section
when given the pragmas

	#pragma package fib
	#pragma ffi T localfib remotefib remote.so

needing #pragma package is a bit of a kludge
and hopefully could go away later.

this is just the 6 tool chain support.
other architectures will happen once 6 settles down.

code using this to do FFI is in a later CL.

R=r
DELTA=161  (141 added, 14 deleted, 6 changed)
OCL=33783
CL=33795

src/cmd/6c/swt.c

@@ -232,6 +232,19 @@ outcode(void)
 	Binit(&b, f, OWRITE);
 
 	Bprint(&b, "%s\n", thestring);
+	if(nffi > 0) {
+		int i;
+
+		if(package == nil) {
+			yyerror("#pragma ffi without #pragma package");
+			package = "_ffi_";
+		}
+		Bprint(&b, "\n$$  // ffi\n", thestring);
+		Bprint(&b, "package %s\n", package);
+		for(i=0; i<nffi; i++)
+			Bprint(&b, "//ffi %c %s %s %s\n", ffi[i].type, ffi[i].local, ffi[i].remote, ffi[i].path);
+		Bprint(&b, "$$\n\n$$\n\n");
+	}
 	Bprint(&b, "!\n");
 
 	outhist(&b);

src/cmd/ar/ar.c

@@ -1550,6 +1550,7 @@ parsepkgdata(char **pp, char *ep, char **prefixp, char **namep, char **defp)
 
 	// skip white space
 	p = *pp;
+again:
 	while(p < ep && (*p == ' ' || *p == '\t'))
 		p++;
 	if(p == ep)
@@ -1569,7 +1570,13 @@ parsepkgdata(char **pp, char *ep, char **prefixp, char **namep, char **defp)
 		p += 5;
 	else if(strncmp(p, "const ", 6) == 0)
 		p += 6;
-	else{
+	else if(strncmp(p, "//", 2) == 0) {
+		p = memchr(p, '\n', ep - p);
+		if(p == nil)
+			return 0;
+		p++;
+		goto again;
+	} else {
 		fprint(2, "ar: confused in pkg data near <<%.20s>>\n", p);
 		errors++;
 		return -1;

src/cmd/cc/cc.h

@@ -49,6 +49,7 @@ typedef	struct	Hist	Hist;
 typedef	struct	Term	Term;
 typedef	struct	Init	Init;
 typedef	struct	Bits	Bits;
+typedef	struct	Ffi Ffi;
 
 #define	NHUNK		50000L
 #define	BUFSIZ		8192
@@ -436,6 +437,18 @@ struct	Funct
 	Sym*	castfr[NTYPE];
 };
 
+struct	Ffi
+{
+	char	type;
+	char*	local;
+	char*	remote;
+	char*	path;
+};
+
+EXTERN	Ffi	*ffi;
+EXTERN	int	nffi;
+EXTERN	char*	package;
+
 EXTERN struct
 {
 	Type*	tenum;		/* type of entire enum */
@@ -740,6 +753,8 @@ void	pragpack(void);
 void	pragfpround(void);
 void	pragtextflag(void);
 void	pragincomplete(void);
+void	pragffi(void);
+void	pragpackage(void);
 
 /*
  * calls to machine depend part

src/cmd/cc/dpchk.c

@@ -200,13 +200,35 @@ arginit(void)
 	flagbits['X'] = flagbits['o'];
 }
 
+static char*
+getquoted(void)
+{
+	int c;
+	char *t;
+	Rune r;
+
+	c = getnsc();
+	if(c != '"')
+		return nil;
+	t = fmtbuf;
+	for(;;) {
+		r = getr();
+		if(r == ' ' || r == '\n')
+			return nil;
+		if(r == '"')
+			break;
+		t += runetochar(t, &r);
+	}
+	*t = 0;
+	return strdup(fmtbuf);
+}
+
 void
 pragvararg(void)
 {
 	Sym *s;
 	int n, c;
 	char *t;
-	Rune r;
 	Type *ty;
 
 	if(!debug['F'])
@@ -251,20 +273,9 @@ ckflag:
 
 cktype:
 /*#pragma	varargck	type	O	int*/
-	c = getnsc();
-	if(c != '"')
+	t = getquoted();
+	if(t == nil)
 		goto bad;
-	t = fmtbuf;
-	for(;;) {
-		r = getr();
-		if(r == ' ' || r == '\n')
-			goto bad;
-		if(r == '"')
-			break;
-		t += runetochar(t, &r);
-	}
-	*t = 0;
-	t = strdup(fmtbuf);
 	s = getsym();
 	if(s == S)
 		goto bad;
@@ -516,3 +527,64 @@ out:
 	if(debug['f'])
 		print("%s incomplete\n", s->name);
 }
+
+void
+pragffi(void)
+{
+	Sym *local, *remote, *type;
+	char *path;
+	Ffi *f;
+
+	type = getsym();
+	if(type == nil)
+		goto err;
+
+	local = getsym();
+	if(local == nil)
+		goto err;
+
+	remote = getsym();
+	if(remote == nil)
+		goto err;
+
+	path = getquoted();
+	if(path == nil)
+		goto err;
+
+	if(nffi%32 == 0)
+		ffi = realloc(ffi, (nffi+32)*sizeof ffi[0]);
+	f = &ffi[nffi++];
+	f->type = type->name[0];
+	f->local = local->name;
+	f->remote = remote->name;
+	f->path = path;
+	goto out;
+
+err:
+	yyerror("usage: #pragma ffi typechar local remote \"path\"");
+
+out:
+	while(getnsc() != '\n')
+		;
+}
+
+void
+pragpackage(void)
+{
+	Sym *s;
+
+	s = getsym();
+	if(s == nil)
+		goto err;
+
+	package = s->name;
+	goto out;
+
+err:
+	yyerror("malformed #pragma package");
+
+out:
+	while(getnsc() != '\n')
+		;
+}
+

src/cmd/cc/lexbody

@@ -46,6 +46,20 @@ pragvararg(void)
 		;
 }
 
+void
+pragffi(void)
+{
+	while(getnsc() != '\n')
+		;
+}
+
+void
+pragpackage(void)
+{
+	while(getnsc() != '\n')
+		;
+}
+
 void
 pragfpround(void)
 {

src/cmd/cc/macbody

@@ -283,7 +283,7 @@ macdef(void)
 			continue;
 		}
 		if(ischr){
-			if(c == '\\'){ 
+			if(c == '\\'){
 				base = allocn(base, len, 1);
 				base[len++] = c;
 				c = getc();
@@ -400,7 +400,7 @@ macexpand(Sym *s, char *b)
 			print("#expand %s %s\n", s->name, ob);
 		return;
 	}
-	
+
 	nargs = (char)(*s->macro & ~VARMAC) - 1;
 	dots = *s->macro & VARMAC;
 
@@ -737,6 +737,14 @@ macprag(void)
 		pragincomplete();
 		return;
 	}
+	if(s && strcmp(s->name, "ffi") == 0) {
+		pragffi();
+		return;
+	}
+	if(s && strcmp(s->name, "package") == 0) {
+		pragpackage();
+		return;
+	}
 	while(getnsc() != '\n')
 		;
 	return;
@@ -763,7 +771,7 @@ praglib:
 		goto bad;
 
 	/*
-	 * put pragma-line in as a funny history 
+	 * put pragma-line in as a funny history
 	 */
 	c = strlen(symb) + 1;
 	hp = alloc(c);

src/cmd/ld/go.c

@@ -102,7 +102,7 @@ ldpkg(Biobuf *f, int64 len, char *filename)
 	while(*p0 == ' ' || *p0 == '\t' || *p0 == '\n')
 		p0++;
 	if(strncmp(p0, "package ", 8) != 0) {
-		fprint(2, "%s: bad package section in %s\n", argv0, filename);
+		fprint(2, "%s: bad package section in %s - %s\n", argv0, filename, p0);
 		return;
 	}
 	p0 += 8;
@@ -199,8 +199,6 @@ again:
 		return 0;
 
 	// prefix: (var|type|func|const)
-	prefix = p;
-
 	prefix = p;
 	if(p + 6 > ep)
 		return -1;
@@ -251,7 +249,7 @@ again:
 		goto again;
 	} else {
 	err:
-		fprint(2, "%s: confused in pkg data near <<%.20s>>\n", argv0, prefix);
+		fprint(2, "%s: confused in pkg data near <<%.40s>>\n", argv0, prefix);
 		nerrors++;
 		return -1;
 	}