defer

R=r
OCL=23592
CL=23592

3 files changed, 66 insertions, 6 deletions

diff --git a/src/runtime/proc.c b/src/runtime/proc.c
index 7435830ff6..3fe08df94d 100644
--- a/src/runtime/proc.c
+++ b/src/runtime/proc.c
@@ -171,7 +171,7 @@ sys·newproc(int32 siz, byte* fn, byte* arg0)
 
 	if((newg = gfget()) != nil){
 		newg->status = Gwaiting;
-	}else{
+	} else {
 		newg = malg(4096);
 		newg->status = Gwaiting;
 		newg->alllink = allg;
@@ -205,6 +205,41 @@ sys·newproc(int32 siz, byte* fn, byte* arg0)
 }
 
 void
+sys·deferproc(int32 siz, byte* fn, byte* arg0)
+{
+	Defer *d;
+
+	d = mal(sizeof(*d) + siz - sizeof(d->args));
+	d->fn = fn;
+	d->sp = (byte*)&arg0;
+	d->siz = siz;
+	mcpy(d->args, d->sp, d->siz);
+
+	d->link = g->defer;
+	g->defer = d;
+}
+
+void
+sys·deferreturn(int32 arg0)
+{
+	// warning: jmpdefer knows the frame size
+	// of this routine. dont change anything
+	// that might change the frame size
+	Defer *d;
+	byte *sp;
+
+	d = g->defer;
+	if(d == nil)
+		return;
+	sp = (byte*)&arg0;
+	if(d->sp != sp)
+		return;
+	mcpy(d->sp, d->args, d->siz);
+	g->defer = d->link;
+	jmpdefer(d->fn);
+}
+
+void
 tracebackothers(G *me)
 {
 	G *g;
diff --git a/src/runtime/rt0_amd64.s b/src/runtime/rt0_amd64.s
index 8588d61a4e..f8d4a381b3 100644
--- a/src/runtime/rt0_amd64.s
+++ b/src/runtime/rt0_amd64.s
@@ -120,7 +120,7 @@ TEXT setspgoto(SB), 7, $0
 //	if(*val == old){
 //		*val = new;
 //		return 1;
-//	}else
+//	} else
 //		return 0;
 TEXT cas(SB), 7, $0
 	MOVQ	8(SP), BX
@@ -133,3 +133,13 @@ TEXT cas(SB), 7, $0
 	RET
 	MOVL	$1, AX
 	RET
+
+// void jmpdefer(byte*);
+// 1. pop the caller
+// 2. sub 5 bytes from the callers return
+// 3. jmp to the argument
+TEXT jmpdefer(SB), 7, $0
+	MOVQ	8(SP), AX	// function
+	ADDQ	$(8+56), SP	// pop saved PC and callers frame
+	SUBQ	$5, (SP)	// reposition his return address
+	JMP	AX		// and goto function
diff --git a/src/runtime/runtime.h b/src/runtime/runtime.h
index 5552c9e94d..78e2affc62 100644
--- a/src/runtime/runtime.h
+++ b/src/runtime/runtime.h
@@ -52,6 +52,7 @@ typedef	struct	SigTab		SigTab;
 typedef	struct	MCache		MCache;
 typedef	struct	Iface		Iface;
 typedef	struct	Itype		Itype;
+typedef	struct	Defer		Defer;
 
 /*
  * per cpu declaration
@@ -128,6 +129,7 @@ struct	G
 {
 	byte*	stackguard;	// must not move
 	byte*	stackbase;	// must not move
+	Defer*	defer;		// must not move
 	byte*	stack0;		// first stack segment
 	Gobuf	sched;
 	G*	alllink;	// on allg
@@ -136,8 +138,8 @@ struct	G
 	int32	goid;
 	int32	selgen;		// valid sudog pointer
 	G*	schedlink;
-	bool		readyonstop;
-	M*	m;	// for debuggers
+	bool	readyonstop;
+	M*	m;		// for debuggers
 };
 struct	Mem
 {
@@ -151,8 +153,8 @@ struct	M
 	G*	g0;		// g0 w interrupt stack - must not move
 	uint64	morearg;	// arg to morestack - must not move
 	uint64	cret;		// return value from C - must not move
-	uint64	procid;	// for debuggers - must not move
-	G*	gsignal;		// signal-handling G - must not move
+	uint64	procid;		// for debuggers - must not move
+	G*	gsignal;	// signal-handling G - must not move
 	G*	curg;		// current running goroutine
 	G*	lastg;		// last running goroutine - to emulate fifo
 	Gobuf	sched;
@@ -236,6 +238,18 @@ enum
 };
 
 /*
+ * defered subroutine calls
+ */
+struct Defer
+{
+	int32	siz;
+	byte*	sp;
+	byte*	fn;
+	Defer*	link;
+	byte	args[8];	// padded to actual size
+};
+
+/*
  * external data
  */
 extern	Alg	algarray[Amax];
@@ -286,6 +300,7 @@ int32	write(int32, void*, int32);
 void	close(int32);
 int32	fstat(int32, void*);
 bool	cas(uint32*, uint32, uint32);
+void	jmpdefer(byte*);
 void	exit1(int32);
 void	ready(G*);
 byte*	getenv(int8*);