Move cdata logic to assembly in Go 1.4+.

Fixes go-qml#106.

Author: niemeyer

cdata/cdata.go

@@ -1,5 +1,4 @@
-// This package supports the implementation of the qml package,
-// and must not be used by itself.
+// Package cdata supports the implementation of the qml package.
 package cdata
 
 func Ref() uintptr

cdata/cdata.c renamed to cdata/cdata12.c

@@ -1,3 +1,5 @@
+// +build !go1.4
+
 #include "runtime.h"
 
 void ·Ref(uintptr ref) {

cdata/cdata14_386.s

@@ -0,0 +1,17 @@
+// +build go1.4
+
+#include "textflag.h"
+
+TEXT ·Ref(SB),NOSPLIT,$4-4
+	CALL runtime·acquirem(SB)
+	MOVL 0(SP), AX
+	MOVL AX, ret+0(FP)
+	CALL runtime·releasem(SB)
+	RET
+
+TEXT ·Addrs(SB),NOSPLIT,$0-8
+	MOVL	$runtime·main(SB), AX
+	MOVL	AX, ret+0(FP)
+	MOVL	$runtime·main_main(SB), AX
+	MOVL	AX, ret+8(FP)
+	RET

cdata/cdata14_amd64.s

@@ -0,0 +1,17 @@
+// +build go1.4
+
+#include "textflag.h"
+
+TEXT ·Ref(SB),NOSPLIT,$8-8
+	CALL runtime·acquirem(SB)
+	MOVQ 0(SP), AX
+	MOVQ AX, ret+0(FP)
+	CALL runtime·releasem(SB)
+	RET
+
+TEXT ·Addrs(SB),NOSPLIT,$0-16
+	MOVQ	$runtime·main(SB), AX
+	MOVQ	AX, ret+0(FP)
+	MOVQ	$runtime·main_main(SB), AX
+	MOVQ	AX, ret+8(FP)
+	RET

cdata/cdata14_arm.s

@@ -0,0 +1,18 @@
+// +build go1.4
+
+#include "textflag.h"
+
+TEXT ·Ref(SB),NOSPLIT,$4-4
+	BL runtime·acquirem(SB)
+	MOVW 4(R13), R0
+	MOVW R0, ret+0(FP)
+	MOVW R0, 4(R13)
+	BL runtime·releasem(SB)
+	RET
+
+TEXT ·Addrs(SB),NOSPLIT,$0-8
+	MOVW	$runtime·main(SB), R0
+	MOVW	R0, ret+0(FP)
+	MOVW	$runtime·main_main(SB), R0
+	MOVW	R0, ret+4(FP)
+	RET

cdata/cdata_test.go

@@ -6,29 +6,37 @@ import (
 	"testing"
 )
 
+type refPair struct {
+	ref1, ref2 uintptr
+}
+
 func TestRef(t *testing.T) {
 	const N = 10
 	runtime.LockOSThread()
+	exit := sync.WaitGroup{}
+	exit.Add(1)
+	defer exit.Done()
 	wg := sync.WaitGroup{}
 	wg.Add(N)
-	ch := make(chan uintptr)
+	ch := make(chan refPair)
 	for i := 0; i < N; i++ {
 		go func() {
 			runtime.LockOSThread()
 			wg.Done()
-			ch <- Ref()
-			wg.Wait()
+			ch <- refPair{Ref(), Ref()}
+			exit.Wait()
 		}()
 	}
 	wg.Wait()
-	refs := []uintptr{Ref()}
+	refs := make(map[uintptr]bool)
 	for i := 0; i < N; i++ {
-		chref := <-ch
-		for _, ref := range refs {
-			if chref == ref {
-				t.Fatalf("found duplicated ref: %d == %d", chref, ref)
-			}
+		pair := <-ch
+		if pair.ref1 != pair.ref2 {
+			t.Fatalf("found inconsistent ref: %d != %d", pair.ref1, pair.ref2)
+		}
+		if refs[pair.ref1] {
+			t.Fatalf("found duplicated ref: %d", pair.ref1)
 		}
-		refs = append(refs, chref)
+		refs[pair.ref1] = true
 	}
 }