5 files changed, 85 insertions, 38 deletions
diff --git a/src/internal/abi/abi.go b/src/internal/abi/abi.go
index eadff248d9..46dc593bd7 100644
--- a/src/internal/abi/abi.go
+++ b/src/internal/abi/abi.go
@@ -19,6 +19,14 @@ import (
 // when it may not be safe to keep them only in the integer
 // register space otherwise.
 type RegArgs struct {
+	// Values in these slots should be precisely the bit-by-bit
+	// representation of how they would appear in a register.
+	//
+	// This means that on big endian arches, integer values should
+	// be in the top bits of the slot. Floats are usually just
+	// directly represented, but some architectures treat narrow
+	// width floating point values specially (e.g. they're promoted
+	// first, or they need to be NaN-boxed).
 	Ints   [IntArgRegs]uintptr  // untyped integer registers
 	Floats [FloatArgRegs]uint64 // untyped float registers
 
@@ -56,26 +64,6 @@ func (r *RegArgs) IntRegArgAddr(reg int, argSize uintptr) unsafe.Pointer {
 	return unsafe.Pointer(uintptr(unsafe.Pointer(&r.Ints[reg])) + offset)
 }
 
-// FloatRegArgAddr returns a pointer inside of r.Floats[reg] that is appropriately
-// offset for an argument of size argSize.
-//
-// argSize must be non-zero, fit in a register, and a power-of-two.
-//
-// This method is a helper for dealing with the endianness of different CPU
-// architectures, since sub-word-sized arguments in big endian architectures
-// need to be "aligned" to the upper edge of the register to be interpreted
-// by the CPU correctly.
-func (r *RegArgs) FloatRegArgAddr(reg int, argSize uintptr) unsafe.Pointer {
-	if argSize > EffectiveFloatRegSize || argSize == 0 || argSize&(argSize-1) != 0 {
-		panic("invalid argSize")
-	}
-	offset := uintptr(0)
-	if goarch.BigEndian {
-		offset = EffectiveFloatRegSize - argSize
-	}
-	return unsafe.Pointer(uintptr(unsafe.Pointer(&r.Floats[reg])) + offset)
-}
-
 // IntArgRegBitmap is a bitmap large enough to hold one bit per
 // integer argument/return register.
 type IntArgRegBitmap [(IntArgRegs + 7) / 8]uint8
diff --git a/src/internal/buildcfg/cfg.go b/src/internal/buildcfg/cfg.go
index 9fe7f211fb..68c10a2824 100644
--- a/src/internal/buildcfg/cfg.go
+++ b/src/internal/buildcfg/cfg.go
@@ -25,6 +25,7 @@ var (
 	GOARCH   = envOr("GOARCH", defaultGOARCH)
 	GOOS     = envOr("GOOS", defaultGOOS)
 	GO386    = envOr("GO386", defaultGO386)
+	GOAMD64  = goamd64()
 	GOARM    = goarm()
 	GOMIPS   = gomips()
 	GOMIPS64 = gomips64()
@@ -52,6 +53,21 @@ func envOr(key, value string) string {
 	return value
 }
 
+func goamd64() int {
+	switch v := envOr("GOAMD64", defaultGOAMD64); v {
+	case "v1":
+		return 1
+	case "v2":
+		return 2
+	case "v3":
+		return 3
+	case "v4":
+		return 4
+	}
+	Error = fmt.Errorf("invalid GOAMD64: must be v1, v2, v3, v4")
+	return int(defaultGOAMD64[len("v")] - '0')
+}
+
 func goarm() int {
 	def := defaultGOARM
 	if GOOS == "android" && GOARCH == "arm" {
diff --git a/src/internal/buildcfg/cfg_test.go b/src/internal/buildcfg/cfg_test.go
new file mode 100644
index 0000000000..9180441c28
--- /dev/null
+++ b/src/internal/buildcfg/cfg_test.go
@@ -0,0 +1,25 @@
+// Copyright 2021 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 buildcfg
+
+import (
+	"os"
+	"testing"
+)
+
+func TestConfigFlags(t *testing.T) {
+	os.Setenv("GOAMD64", "v1")
+	if goamd64() != 1 {
+		t.Errorf("Wrong parsing of GOAMD64=v1")
+	}
+	os.Setenv("GOAMD64", "v4")
+	if goamd64() != 4 {
+		t.Errorf("Wrong parsing of GOAMD64=v4")
+	}
+	os.Setenv("GOAMD64", "1")
+	if goamd64() != 1 {
+		t.Errorf("Wrong parsing of GOAMD64=1")
+	}
+}
diff --git a/src/internal/cfg/cfg.go b/src/internal/cfg/cfg.go
index 815994b679..4cb3fbd4f3 100644
--- a/src/internal/cfg/cfg.go
+++ b/src/internal/cfg/cfg.go
@@ -33,6 +33,7 @@ const KnownEnv = `
 	GCCGO
 	GO111MODULE
 	GO386
+	GOAMD64
 	GOARCH
 	GOARM
 	GOBIN
diff --git a/src/internal/poll/splice_linux_test.go b/src/internal/poll/splice_linux_test.go
index 280468c7e7..8c4363886e 100644
--- a/src/internal/poll/splice_linux_test.go
+++ b/src/internal/poll/splice_linux_test.go
@@ -6,40 +6,48 @@ package poll_test
 
 import (
 	"internal/poll"
-	"internal/syscall/unix"
 	"runtime"
-	"syscall"
+	"sync"
+	"sync/atomic"
 	"testing"
 	"time"
 )
 
-// checkPipes returns true if all pipes are closed properly, false otherwise.
-func checkPipes(fds []int) bool {
-	for _, fd := range fds {
-		// Check if each pipe fd has been closed.
-		_, _, errno := syscall.Syscall(unix.FcntlSyscall, uintptr(fd), syscall.F_GETPIPE_SZ, 0)
-		if errno == 0 {
-			return false
+var closeHook atomic.Value // func(fd int)
+
+func init() {
+	closeFunc := poll.CloseFunc
+	poll.CloseFunc = func(fd int) (err error) {
+		if v := closeHook.Load(); v != nil {
+			if hook := v.(func(int)); hook != nil {
+				hook(fd)
+			}
 		}
+		return closeFunc(fd)
 	}
-	return true
 }
 
 func TestSplicePipePool(t *testing.T) {
 	const N = 64
 	var (
-		p   *poll.SplicePipe
-		ps  []*poll.SplicePipe
-		fds []int
-		err error
+		p          *poll.SplicePipe
+		ps         []*poll.SplicePipe
+		allFDs     []int
+		pendingFDs sync.Map // fd → struct{}{}
+		err        error
 	)
+
+	closeHook.Store(func(fd int) { pendingFDs.Delete(fd) })
+	t.Cleanup(func() { closeHook.Store((func(int))(nil)) })
+
 	for i := 0; i < N; i++ {
 		p, _, err = poll.GetPipe()
 		if err != nil {
-			t.Skip("failed to create pipe, skip this test")
+			t.Skipf("failed to create pipe due to error(%v), skip this test", err)
 		}
 		_, pwfd := poll.GetPipeFds(p)
-		fds = append(fds, pwfd)
+		allFDs = append(allFDs, pwfd)
+		pendingFDs.Store(pwfd, struct{}{})
 		ps = append(ps, p)
 	}
 	for _, p = range ps {
@@ -62,12 +70,21 @@ func TestSplicePipePool(t *testing.T) {
 	for {
 		runtime.GC()
 		time.Sleep(10 * time.Millisecond)
-		if checkPipes(fds) {
+
+		// Detect whether all pipes are closed properly.
+		var leakedFDs []int
+		pendingFDs.Range(func(k, v interface{}) bool {
+			leakedFDs = append(leakedFDs, k.(int))
+			return true
+		})
+		if len(leakedFDs) == 0 {
 			break
 		}
+
 		select {
 		case <-expiredTime.C:
-			t.Fatal("at least one pipe is still open")
+			t.Logf("all descriptors: %v", allFDs)
+			t.Fatalf("leaked descriptors: %v", leakedFDs)
 		default:
 		}
 	}