build: add all-qemu.bash, handful of arm fixes

R=r
CC=golang-dev
https://golang.org/cl/4313051

doc/codelab/wiki/Makefile

@@ -8,7 +8,7 @@ all: index.html
 
 include ../../../src/Make.common
 
-CLEANFILES+=index.html srcextract.bin htmlify.bin
+CLEANFILES+=index.html srcextract.bin htmlify.bin get.bin
 
 index.html: srcextract.bin htmlify.bin
 	PATH=.:$$PATH awk '/^!/{system(substr($$0,2)); next} {print}' < wiki.html | tr -d '\r' > index.html

src/all-qemu.bash

@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+# Copyright 2011 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.
+
+# Run all.bash but exclude tests that depend on functionality
+# missing in QEMU's system call emulation.
+
+export DISABLE_NET_TESTS=1  # no external network
+export NOTEST=""
+
+NOTEST="$NOTEST big" # xxx
+NOTEST="$NOTEST http net rpc syslog websocket"  # no localhost network
+NOTEST="$NOTEST os"  # 64-bit seek fails
+
+./all.bash

src/pkg/Makefile

@@ -169,7 +169,7 @@ DIRS+=\
 
 endif
 
-NOTEST=\
+NOTEST+=\
 	crypto\
 	crypto/openpgp/error\
 	debug/proc\
@@ -196,7 +196,7 @@ NOTEST=\
 	../cmd/goyacc\
 	../cmd/hgpatch\
 
-NOBENCH=\
+NOBENCH+=\
 	container/vector\
 
 # Disable tests that depend on an external network.

src/pkg/go/printer/printer_test.go

@@ -114,7 +114,7 @@ func check(t *testing.T, source, golden string, mode checkMode) {
 	// start a timer to produce a time-out signal
 	tc := make(chan int)
 	go func() {
-		time.Sleep(2e9) // plenty of a safety margin, even for very slow machines
+		time.Sleep(10e9) // plenty of a safety margin, even for very slow machines
 		tc <- 0
 	}()
 

src/pkg/runtime/linux/arm/signal.c

@@ -135,6 +135,8 @@ sigaction(int32 i, void (*fn)(int32, Siginfo*, void*, G*), bool restart)
 		sa.sa_flags |= SA_RESTART;
 	sa.sa_mask = ~0ULL;
 	sa.sa_restorer = (void*)runtime·sigreturn;
+	if(fn == runtime·sighandler)
+		fn = (void*)runtime·sigtramp;
 	sa.sa_handler = fn;
 	runtime·rt_sigaction(i, &sa, nil, 8);
 }

src/pkg/runtime/linux/signals.h

@@ -13,7 +13,7 @@ SigTab runtime·sigtab[] = {
 	/* 1 */	Q+R, "SIGHUP: terminal line hangup",
 	/* 2 */	Q+R, "SIGINT: interrupt",
 	/* 3 */	C, "SIGQUIT: quit",
-	/* 4 */	C, "SIGILL: illegal instruction",
+	/* 4 */	C+P, "SIGILL: illegal instruction",
 	/* 5 */	C, "SIGTRAP: trace trap",
 	/* 6 */	C, "SIGABRT: abort",
 	/* 7 */	C+P, "SIGBUS: bus error",

src/pkg/sync/atomic/asm_arm.s

@@ -25,6 +25,7 @@ casfail:
 	RET
 
 TEXT ·armCompareAndSwapUint64(SB),7,$0
+	BL	fastCheck64<>(SB)
 	MOVW	valptr+0(FP), R1
 	MOVW	oldlo+4(FP), R2
 	MOVW	oldhi+8(FP), R3
@@ -62,6 +63,7 @@ addloop:
 	RET
 
 TEXT ·armAddUint64(SB),7,$0
+	BL	fastCheck64<>(SB)
 	MOVW	valptr+0(FP), R1
 	MOVW	deltalo+4(FP), R2
 	MOVW	deltahi+8(FP), R3
@@ -76,3 +78,42 @@ add64loop:
 	MOVW	R4, retlo+12(FP)
 	MOVW	R5, rethi+16(FP)
 	RET
+
+// Check for broken 64-bit LDREXD as found in QEMU.
+// LDREXD followed by immediate STREXD should succeed.
+// If it fails, try a few times just to be sure (maybe our thread got
+// rescheduled between the two instructions) and then panic.
+// A bug in some copies of QEMU makes STREXD never succeed,
+// which will make uses of the 64-bit atomic operations loop forever.
+// If things are working, set okLDREXD to avoid future checks.
+// https://bugs.launchpad.net/qemu/+bug/670883.
+TEXT	check64<>(SB),7,$8
+	MOVW	$10, R1
+loop:
+	LDREXD	(SP), R2
+	STREXD	R2, (SP), R0
+	CMP	$0, R0
+	BEQ	ok
+	SUB	$1, R1
+	CMP	$0, R1
+	BNE	loop
+	// Must be buggy QEMU.
+	BL	·panic64(SB)
+ok:
+	RET
+
+// Fast, cached version of check.  No frame, just MOVW CMP RET after first time.
+TEXT	fastCheck64<>(SB),7,$-4
+	MOVW	ok64<>(SB), R0
+	CMP	$0, R0	// have we been here before?
+	RET.NE
+	B	slowCheck64<>(SB)
+
+TEXT slowCheck64<>(SB),7,$0
+	BL	check64<>(SB)
+	// Still here, must be okay.
+	MOVW	$1, R0
+	MOVW	R0, ok64<>(SB)
+	RET
+
+GLOBL ok64<>(SB), $4

src/pkg/sync/atomic/atomic_test.go

@@ -2,10 +2,11 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package atomic
+package atomic_test
 
 import (
 	"runtime"
+	. "sync/atomic"
 	"testing"
 	"unsafe"
 )
@@ -27,6 +28,16 @@ const (
 	magic64 = 0xdeddeadbeefbeef
 )
 
+// Do the 64-bit functions panic?  If so, don't bother testing.
+var test64err = func() (err interface{}) {
+	defer func() {
+		err = recover()
+	}()
+	var x int64
+	AddInt64(&x, 1)
+	return nil
+}()
+
 func TestAddInt32(t *testing.T) {
 	var x struct {
 		before int32
@@ -70,6 +81,10 @@ func TestAddUint32(t *testing.T) {
 }
 
 func TestAddInt64(t *testing.T) {
+	if test64err != nil {
+		t.Logf("Skipping 64-bit tests: %v", test64err)
+		return
+	}
 	var x struct {
 		before int64
 		i      int64
@@ -91,6 +106,10 @@ func TestAddInt64(t *testing.T) {
 }
 
 func TestAddUint64(t *testing.T) {
+	if test64err != nil {
+		t.Logf("Skipping 64-bit tests: %v", test64err)
+		return
+	}
 	var x struct {
 		before uint64
 		i      uint64
@@ -193,6 +212,10 @@ func TestCompareAndSwapUint32(t *testing.T) {
 }
 
 func TestCompareAndSwapInt64(t *testing.T) {
+	if test64err != nil {
+		t.Logf("Skipping 64-bit tests: %v", test64err)
+		return
+	}
 	var x struct {
 		before int64
 		i      int64
@@ -222,6 +245,10 @@ func TestCompareAndSwapInt64(t *testing.T) {
 }
 
 func TestCompareAndSwapUint64(t *testing.T) {
+	if test64err != nil {
+		t.Logf("Skipping 64-bit tests: %v", test64err)
+		return
+	}
 	var x struct {
 		before uint64
 		i      uint64
@@ -479,6 +506,10 @@ func hammerCompareAndSwapUintptr64(uval *uint64, count int) {
 }
 
 func TestHammer64(t *testing.T) {
+	if test64err != nil {
+		t.Logf("Skipping 64-bit tests: %v", test64err)
+		return
+	}
 	const p = 4
 	n := 100000
 	if testing.Short() {

src/pkg/sync/atomic/doc.go

@@ -55,3 +55,8 @@ func AddUint64(val *uint64, delta uint64) (new uint64)
 
 // AddUintptr atomically adds delta to *val and returns the new value.
 func AddUintptr(val *uintptr, delta uintptr) (new uintptr)
+
+// Helper for ARM.  Linker will discard on other systems
+func panic64() {
+	panic("sync/atomic: broken 64-bit atomic operations (buggy QEMU)")
+}

src/run.bash

@@ -98,6 +98,7 @@ time gomake ogle
 time ./run
 ) || exit $?
 
+[ "$GOARCH" == arm ] ||  # uses network, fails under QEMU
 (xcd ../doc/codelab/wiki
 gomake clean
 gomake

test/fixedbugs/bug243.go

@@ -6,12 +6,14 @@
 
 package main
 
-import (
+import "os"
-	"net"
+
-)
+// Issue 481: closures and var declarations
+// with multiple variables assigned from one
+// function call.
 
 func main() {
-	var listen, _ = net.Listen("tcp", "127.0.0.1:0")
+	var listen, _ = Listen("tcp", "127.0.0.1:0")
 
 	go func() {
 		for {
@@ -20,6 +22,31 @@ func main() {
 		}
 	}()
 
-	var conn, _ = net.Dial("tcp", "", listen.Addr().String())
+	var conn, _ = Dial("tcp", "", listen.Addr().String())
 	_ = conn
 }
+
+// Simulated net interface to exercise bug
+// without involving a real network.
+type T chan int
+
+var global T
+
+func Listen(x, y string) (T, string) {
+	global = make(chan int)
+	return global, y
+}
+
+func (t T) Addr() os.Error {
+	return os.ErrorString("stringer")
+}
+
+func (t T) Accept() (int, string) {
+	return <-t, ""
+}
+
+func Dial(x, y, z string) (int, string) {
+	global <- 1
+	return 0, ""
+}
+