cmd/dist: re-enable GOARM auto-detection
cmd/dist will re-exec itself to detect VFP support at run-time.
Fixes #9732, #12548.
Change-Id: I9ad0c5c7fa3e97bd79a32da372e1a962565bb3af
Reviewed-on: https://go-review.googlesource.com/3973
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/src/cmd/dist/util.go b/src/cmd/dist/util.go
index f13210f..34cbf50 100644
--- a/src/cmd/dist/util.go
+++ b/src/cmd/dist/util.go
@@ -480,6 +480,14 @@
}
}
+ if len(os.Args) > 1 && os.Args[1] == "-check-goarm" {
+ useVFPv1() // might fail with SIGILL
+ println("VFPv1 OK.")
+ useVFPv3() // might fail with SIGILL
+ println("VFPv3 OK.")
+ os.Exit(0)
+ }
+
xinit()
xmain()
xexit(0)
@@ -515,40 +523,21 @@
// OpenBSD currently only supports softfloat.
return "5"
}
- if goos != "linux" {
- // All other arm platforms that we support
- // require ARMv7.
+
+ // Try to exec ourselves in a mode to detect VFP support.
+ // Seeing how far it gets determines which instructions failed.
+ // The test is OS-agnostic.
+ out := run("", 0, os.Args[0], "-check-goarm")
+ v1ok := strings.Contains(out, "VFPv1 OK.")
+ v3ok := strings.Contains(out, "VFPv3 OK.")
+
+ if v1ok && v3ok {
return "7"
}
- 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"
- }
- }
+ if v1ok {
+ return "6"
}
- return goarm
+ return "5"
}
func min(a, b int) int {
diff --git a/src/cmd/dist/util_gc.go b/src/cmd/dist/util_gc.go
index 9f6cfd0..81e52b6 100644
--- a/src/cmd/dist/util_gc.go
+++ b/src/cmd/dist/util_gc.go
@@ -17,3 +17,11 @@
cpuid(&info, 1)
return info[3]&(1<<26) != 0 // SSE2
}
+
+// useVFPv1 tries to execute one VFPv1 instruction on ARM.
+// It will crash the current process if VFPv1 is missing.
+func useVFPv1()
+
+// useVFPv3 tries to execute one VFPv3 instruction on ARM.
+// It will crash the current process if VFPv3 is missing.
+func useVFPv3()
diff --git a/src/cmd/dist/util_gccgo.go b/src/cmd/dist/util_gccgo.go
index 14ac70b..18e328f 100644
--- a/src/cmd/dist/util_gccgo.go
+++ b/src/cmd/dist/util_gccgo.go
@@ -18,3 +18,7 @@
import "C"
func cansse2() bool { return C.supports_sse2() != 0 }
+
+func useVFPv1() {}
+
+func useVFPv3() {}
diff --git a/src/cmd/dist/vfp_arm.s b/src/cmd/dist/vfp_arm.s
new file mode 100644
index 0000000..647c439
--- /dev/null
+++ b/src/cmd/dist/vfp_arm.s
@@ -0,0 +1,17 @@
+// 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 gc,arm
+
+#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
new file mode 100644
index 0000000..5cf9997
--- /dev/null
+++ b/src/cmd/dist/vfp_default.s
@@ -0,0 +1,13 @@
+// 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,gc
+
+#include "textflag.h"
+
+TEXT ·useVFPv1(SB),NOSPLIT,$0
+ RET
+
+TEXT ·useVFPv3(SB),NOSPLIT,$0
+ RET
