cgocall bug fix.

better FFI demo: compute fibonacci numbers using FFI'ed libgmp.

R=r
DELTA=281  (255 added, 19 deleted, 7 changed)
OCL=33815
CL=33820

src/libcgo/cgocall.c

@@ -218,7 +218,6 @@ newserver(void)
 	pthread_t p;
 
 	lock(&cgo.lock);
-	if(cgo.idle == nil) {
 	// kick off new servers with work to do
 	for(w=cgo.whead; w; w=next) {
 		next = w;
@@ -237,6 +236,7 @@ newserver(void)
 	cgo.wtail = nil;
 
 	// kick off one more server to sit idle
+	if(cgo.idle == nil) {
 		f = malloc(sizeof *f);
 		memset(f, 0, sizeof *f);
 		f->next = cgo.idle;
@@ -256,23 +256,41 @@ go_pthread(void *v)
 	CgoServer *f;
 	CgoWork *w;
 
+	// newserver queued us; wait for work
 	f = v;
+	goto wait;
+
 	for(;;) {
-		// wait for work
-		notesleep(&f->note);
+		// kick off new server to handle requests while we work
+		newserver();
 
 		// do work
 		w = f->work;
 		w->fn(w->arg);
 		notewakeup(&w->note);
+		f->work = nil;
 
-		// queue f on idle list
+		// take some work if available
+		lock(&cgo.lock);
+		if((w = cgo.whead) != nil) {
+			cgo.whead = w->next;
+			if(cgo.whead == nil)
+				cgo.wtail = nil;
+			unlock(&cgo.lock);
+			f->work = w;
+			continue;
+		}
+
+		// otherwise queue
 		f->work = nil;
 		noteclear(&f->note);
-		lock(&cgo.lock);
 		f->next = cgo.idle;
 		cgo.idle = f;
 		unlock(&cgo.lock);
+
+wait:
+		// wait for work
+		notesleep(&f->note);
 	}
 }
 

usr/rsc/gmp/6c.c

@@ -0,0 +1,60 @@
+// Copyright 2009 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.
+
+#include "runtime.h"
+#include "cgocall.h"
+
+typedef struct Int Int;
+struct Int
+{
+	void *v;
+};
+
+// turn on ffi
+#pragma dynld initcgo initcgo "libcgo.so"
+#pragma dynld cgo cgo "libcgo.so"
+
+// pull in gmp routines, implemented in gcc.c, from gmp.so
+
+#pragma dynld gmp_addInt gmp_addInt "gmp.so"
+void (*gmp_addInt)(void*);
+
+#pragma dynld gmp_stringInt gmp_stringInt "gmp.so"
+void (*gmp_stringInt)(void*);
+
+#pragma dynld gmp_newInt gmp_newInt "gmp.so"
+void (*gmp_newInt)(void*);
+
+#pragma dynld c_free free "gmp.so"
+void (*c_free)(void*);
+void
+gmp·addInt(Int *z, Int *x, Int *y, Int *ret)
+{
+	cgocall(gmp_addInt, &z);
+}
+
+void
+gmp·stringInt(Int *z, String ret)
+{
+	struct {
+		Int *z;
+		byte *p;
+	} a;
+	a.z = z;
+	a.p = nil;
+	cgocall(gmp_stringInt, &a);
+	ret = gostring(a.p);
+	cgocall(c_free, a.p);
+	FLUSH(&ret);
+}
+
+void
+gmp·NewInt(uint64 x, Int *z)
+{
+if(sizeof(uintptr) != 8) *(int32*)0 = 0;
+	z = mallocgc(sizeof *z);
+	FLUSH(&z);
+	cgocall(gmp_newInt, &x);
+}
+

usr/rsc/gmp/Makefile

@@ -0,0 +1,52 @@
+# Copyright 2009 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.
+
+# FFI demo
+
+include ../../../src/Make.$(GOARCH)
+
+all: gmp.a gmp.so
+
+gcc.o: gcc.c
+	gcc -fPIC -O2 -o gcc.o -c gcc.c
+
+gmp.so: gcc.o
+	gcc -shared -o gmp.so gcc.o -L$(GOROOT)/pkg/$(GOOS)_$(GOARCH) -lcgo -lgmp
+
+gmp.a: 6c.6 go.6
+	gopack grc gmp.a 6c.6 go.6
+
+# from pkg/runtime/Makefile: TODO(rsc): how to deal with this?
+# Set SIZE to 32 or 64.
+SIZE_386=32
+SIZE_amd64=64
+SIZE_arm=32
+SIZE=$(SIZE_$(GOARCH))
+
+# Setup CFLAGS.  Add -D_64BIT on 64-bit platforms (sorry).
+CFLAGS_64=-D_64BIT
+# TODO(kaib): fix register allocation to honor extern register so we
+# can enable optimizations again.
+CFLAGS_arm=-N
+CFLAGS=-I$(GOOS) -I$(GOOS)/$(GOARCH) -wF $(CFLAGS_$(SIZE)) $(CFLAGS_$(GOARCH))
+
+6c.6: 6c.c
+	6c -FVw $(CFLAGS) -I$(GOROOT)/src/pkg/runtime 6c.c
+
+go.6: go.go
+	6g go.go
+
+PKG=$(GOROOT)/pkg/$(GOOS)_$(GOARCH)
+
+install: $(PKG)/gmp.so $(PKG)/gmp.a
+
+$(PKG)/gmp.so: gmp.so
+	cp gmp.so $@
+
+$(PKG)/gmp.a: gmp.a
+	cp gmp.a $@
+
+clean:
+	rm -f *.6 *.o *.so *.a
+

usr/rsc/gmp/gcc.c

@@ -0,0 +1,54 @@
+// Copyright 2009 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.
+
+#include <stdint.h>
+#include <gmp.h>
+#include <string.h>
+
+typedef int32_t int32;
+typedef uint64_t uint64;
+
+typedef struct Int Int;
+struct Int
+{
+	mpz_t *mp;
+};
+
+void
+gmp_newInt(void *v)
+{
+	struct {
+		uint64 x;
+		Int *z;
+	} *a = v;
+
+	a->z->mp = malloc(sizeof *a->z->mp);
+	mpz_init_set_ui(*a->z->mp, a->x);
+}
+
+void
+gmp_addInt(void *v)
+{
+	struct {
+		Int *z;
+		Int *x;
+		Int *y;
+		Int *ret;
+	} *a = v;
+
+	a->ret = a->z;
+	mpz_add(*a->z->mp, *a->x->mp, *a->y->mp);
+}
+
+void
+gmp_stringInt(void *v)
+{
+	struct {
+		Int *z;
+		char *p;
+	} *a = v;
+
+	a->p = mpz_get_str(NULL, 10, *a->z->mp);
+}
+

usr/rsc/gmp/go.go

@@ -0,0 +1,24 @@
+// Copyright 2009 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 gmp
+
+type Int struct {
+	hidden *byte
+}
+
+func addInt(z, x, y *Int) *Int
+
+func (z *Int) Add(x, y *Int) *Int {
+	return addInt(z, x, y)
+}
+
+func stringInt(z *Int) string
+
+func (z *Int) String() string {
+	return stringInt(z)
+}
+
+func NewInt(n uint64) *Int
+

usr/rsc/gmp/main.go

@@ -0,0 +1,28 @@
+// Copyright 2009 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 big "gmp"
+//import "big"
+import "fmt"
+
+func Fib(n int) *big.Int {
+	a := big.NewInt(0);
+	b := big.NewInt(1);
+
+	for i := 0; i < n; i++ {
+		a, b = b, a;
+		b.Add(a, b);
+	}
+
+	return b;
+}
+
+func main() {
+	for i := 0; i <= 100; i++ {
+		fmt.Println(5*i, Fib(5*i));
+	}
+}