first version of closures. test/closure doesn't yet pass.

go/test: passes 87% (300/343)

R=rsc
APPROVED=rsc
DELTA=125  (125 added, 0 deleted, 0 changed)
OCL=35893
CL=35900

src/pkg/runtime/arm/closure.c

 // 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"
+
+/*
+	There are two bits of magic:
+	- The signature of the compiler generated function uses two stack frames
+	as arguments (callerpc separates these frames)
+	- size determines how many arguments runtime.closure actually has
+	starting at arg0.
+
+	Example closure with 3 captured variables:
+	func closure(siz int32,
+	fn func(arg0, arg1, arg2 *ptr, callerpc uintptr, xxx) yyy,
+		arg0, arg1, arg2 *ptr) (func(xxx) yyy)
+
+	Code generated:
+	src R0
+	dst R1
+	end R3
+	tmp R4
+	frame = siz+4
+
+//skip loop for 0 size closures
+		MOVW.W	R14,-frame(R13)
+
+		MOVW	$vars(PC), R0
+		MOVW	$4(SP), R1
+		MOVW	$siz(R0), R3
+loop:		MOVW.P	4(R0), R4
+		MOVW.P	R4, 4(R1)
+		CMP		R0, R3
+		BNE		loop
+
+		MOVW	8(PC), R0
+		BL		(R0)			// 2 words
+		MOVW.P	frame(R13),R15
+fptr:		WORD	*fn
+vars:		WORD	arg0
+		WORD	arg1
+		WORD	arg2
+*/
+
+#pragma textflag 7
+void
+runtime·closure(int32 siz, byte *fn, byte *arg0)
+{
+	byte *p, *q, **ret;
+	uint32 *pc;
+	int32 n;
+
+	if(siz < 0 || siz%4 != 0)
+		throw("bad closure size");
+
+	ret = (byte**)((byte*)&arg0 + siz);
+
+	if(siz > 100) {
+		// TODO(kaib): implement stack growth preamble?
+		throw("closure too big");
+	}
+
+	// size of new fn.
+	// must match code laid out below.
+	if (siz > 0)
+		n = 6 * 4 + 7 * 4;
+	else
+		n = 6 * 4;
+
+	// store args aligned after code, so gc can find them.
+	n += siz;
+
+	p = mal(n);
+	*ret = p;
+	q = p + n - siz;
+
+	pc = (uint32*)p;
+
+	//	MOVW.W	R14,-frame(R13)
+	*pc++ = 0xe52de000 | (siz + 4);
+
+	if(siz > 0) {
+		mcpy(q, (byte*)&arg0, siz);
+
+		//	MOVW	$vars(PC), R0
+		*pc = 0xe28f0000 | (int32)(q - (byte*)pc - 8);
+		pc++;
+
+		//	MOVW	$4(SP), R1
+		*pc++ = 0xe28d1004;
+
+		//	MOVW	$siz(R0), R3
+		*pc++ = 0xe2803000 | siz;
+
+		//	MOVW.P	4(R0), R4
+		*pc++ = 0xe4904004;
+		//	MOVW.P	R4, 4(R1)
+		*pc++ = 0xe4814004;
+		//	CMP		R0, R3
+		*pc++ = 0xe1530000;
+		//	BNE		loop
+		*pc++ = 0x1afffffb;
+	}
+
+	//	MOVW	fptr(PC), R0
+	*pc = 0xe59f0008 | (int32)((q - 4) -(byte*) pc - 8);
+	pc++;
+
+	//	BL		(R0)
+	*pc++ = 0xe28fe000;
+	*pc++ = 0xe280f000;
+
+	//	MOVW.P	frame(R13),R15
+	*pc++ = 0xe49df000 | (siz + 4);
+
+	//	WORD	*fn
+	*pc++ = (uint32)fn;
+
+	p = (byte*)pc;
+
+	if(p > q)
+		throw("bad math in sys.closure");
+}
+

test/arm-pass.txt

@@ -27,6 +27,7 @@ convlit1.go
 decl.go
 declbad.go
 empty.go
+env.go
 escape1.go
 fixedbugs/bug000.go
 fixedbugs/bug001.go
@@ -83,6 +84,7 @@ fixedbugs/bug063.go
 fixedbugs/bug064.go
 fixedbugs/bug065.go
 fixedbugs/bug066.go
+fixedbugs/bug067.go
 fixedbugs/bug068.go
 fixedbugs/bug069.go
 fixedbugs/bug070.go
@@ -253,6 +255,7 @@ ken/interbasic.go
 ken/interfun.go
 ken/intervar.go
 ken/label.go
+ken/litfun.go
 ken/mfunc.go
 ken/ptrfun.go
 ken/ptrvar.go