cmd/dist: reactivate vfp detection on linux/arm

Fixes #9732
Fixes #9819

Rather than detecting vfp support via catching SIGILL signals,
parse the contents of /proc/cpuinfo.

As the GOARM values for NaCl and freebsd are hard coded, this parsing
logic only needs to support linux/arm.

This change also fixes the nacl/arm build which is broken because the
first stage of nacltest.bash is executed with GOARM=5, embedding that
into 5g.

The second stage of nacltest.bash correctly detects GOARM=7, but this is
ignored as we pass --no-clean at that point, and thus do not replace
the compiler.

Lastyly, include a fix to error message in nacltest.bash

Change-Id: I13f306ff07a99b44b493fade72ac00d0d5097e1c
Reviewed-on: https://go-review.googlesource.com/3981
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

diff --git a/src/cmd/dist/util.go b/src/cmd/dist/util.go
index 5cdd01b334c2829f50f18588c35ddf697c824f85..e686e42fe1ead68d0d821e3f85d7cab6578f6e55 100644 (file)
--- a/src/cmd/dist/util.go
+++ b/src/cmd/dist/util.go
@@ -471,24 +471,38 @@ func xgetgoarm() string {
                // FreeBSD has broken VFP support.
                return "5"
        }
-       if xtryexecfunc(useVFPv3) {
+       if goos != "linux" {
+               // All other arm platforms that we support
+               // require ARMv7.
                return "7"
        }
-       if xtryexecfunc(useVFPv1) {
-               return "6"
+       cpuinfo := readfile("/proc/cpuinfo")
+       goarm := "5"
+       for _, line := range splitlines(cpuinfo) {
+               line := strings.SplitN(line, ":", 2)
+               if len(line) < 2 {
+                       continue
+               }
+               if strings.TrimSpace(line[0]) != "Features" {
+                       continue
+               }
+               features := splitfields(line[1])
+               sort.Strings(features) // so vfpv3 sorts after vfp
+
+               // Infer GOARM value from the vfp features available
+               // on this host. Values of GOARM detected are:
+               // 5: no vfp support was found
+               // 6: vfp (v1) support was detected, but no higher
+               // 7: vfpv3 support was detected.
+               // This matches the assertions in runtime.checkarm.
+               for _, f := range features {
+                       switch f {
+                       case "vfp":
+                               goarm = "6"
+                       case "vfpv3":
+                               goarm = "7"
+                       }
+               }
        }
-       return "5"
+       return goarm
 }
-
-func xtryexecfunc(f func()) bool {
-       // TODO(rsc): Implement.
-       // The C cmd/dist used this to test whether certain assembly
-       // sequences could be executed properly. It used signals and
-       // timers and sigsetjmp, which is basically not possible in Go.
-       // We probably have to invoke ourselves as a subprocess instead,
-       // to contain the fault/timeout.
-       return false
-}
-
-func useVFPv1()
-func useVFPv3()

diff --git a/src/cmd/dist/vfp_arm.s b/src/cmd/dist/vfp_arm.s
deleted file mode 100644 (file)
index 39052db..0000000
--- a/src/cmd/dist/vfp_arm.s
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright 2015 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 "textflag.h"
-
-// try to run "vmov.f64 d0, d0" instruction
-TEXT ·useVFPv1(SB),NOSPLIT,$0
-       WORD $0xeeb00b40        // vmov.f64 d0, d0
-       RET
-
-// try to run VFPv3-only "vmov.f64 d0, #112" instruction
-TEXT ·useVFPv3(SB),NOSPLIT,$0
-       WORD $0xeeb70b00        // vmov.f64 d0, #112
-       RET

diff --git a/src/cmd/dist/vfp_default.s b/src/cmd/dist/vfp_default.s
deleted file mode 100644 (file)
index c795b35..0000000
--- a/src/cmd/dist/vfp_default.s
+++ /dev/null
@@ -1,14 +0,0 @@
-// Copyright 2015 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.
-
-// +build !arm
-
-#include "textflag.h"
-
-TEXT ·useVFPv1(SB),NOSPLIT,$0
-       RET
-
-TEXT ·useVFPv3(SB),NOSPLIT,$0
-       RET
-

diff --git a/src/nacltest.bash b/src/nacltest.bash
index 6220d39f13d5dc548d493c6095a3b07a0fc6440e..534f1ef5aff54aba304e7009f8231a1dc3f649fc 100755 (executable)
--- a/src/nacltest.bash
+++ b/src/nacltest.bash
@@ -62,7 +62,7 @@ fi
 # Run host build to get toolchain for running zip generator.
 unset GOOS GOARCH
 if [ ! -f make.bash ]; then
-       echo 'nacl.bash must be run from $GOROOT/src' 1>&2
+       echo 'nacltest.bash must be run from $GOROOT/src' 1>&2
        exit 1
 fi
 GOOS=$GOHOSTOS GOARCH=$GOHOSTARCH ./make.bash