libgo: update to Go1.16beta1 release

This does not yet include support for the //go:embed directive added
in this release.

	* Makefile.am (check-runtime): Don't create check-runtime-dir.
	(mostlyclean-local): Don't remove check-runtime-dir.
	(check-go-tool, check-vet): Copy in go.mod and modules.txt.
	(check-cgo-test, check-carchive-test): Add go.mod file.
	* Makefile.in: Regenerate.

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/280172

1 files changed, 39 insertions, 29 deletions

diff --git a/libgo/go/runtime/signal_unix.go b/libgo/go/runtime/signal_unix.go
index ec7c647..1c040f7 100644
--- a/libgo/go/runtime/signal_unix.go
+++ b/libgo/go/runtime/signal_unix.go
@@ -281,6 +281,12 @@ func setProcessCPUProfiler(hz int32) {
 			atomic.Storeuintptr(&fwdSig[_SIGPROF], getsig(_SIGPROF))
 			setsig(_SIGPROF, getSigtramp())
 		}
+
+		var it _itimerval
+		it.it_interval.tv_sec = 0
+		it.it_interval.set_usec(1000000 / hz)
+		it.it_value = it.it_interval
+		setitimer(_ITIMER_PROF, &it, nil)
 	} else {
 		// If the Go signal handler should be disabled by default,
 		// switch back to the signal handler that was installed
@@ -305,23 +311,16 @@ func setProcessCPUProfiler(hz int32) {
 				setsig(_SIGPROF, h)
 			}
 		}
+
+		setitimer(_ITIMER_PROF, &_itimerval{}, nil)
 	}
 }
 
 // setThreadCPUProfiler makes any thread-specific changes required to
 // implement profiling at a rate of hz.
+// No changes required on Unix systems.
 func setThreadCPUProfiler(hz int32) {
-	var it _itimerval
-	if hz == 0 {
-		setitimer(_ITIMER_PROF, &it, nil)
-	} else {
-		it.it_interval.tv_sec = 0
-		it.it_interval.set_usec(1000000 / hz)
-		it.it_value = it.it_interval
-		setitimer(_ITIMER_PROF, &it, nil)
-	}
-	_g_ := getg()
-	_g_.m.profilehz = hz
+	getg().m.profilehz = hz
 }
 
 func sigpipe() {
@@ -348,7 +347,7 @@ func doSigPreempt(gp *g, ctxt *sigctxt, sigpc uintptr) {
 	atomic.Xadd(&gp.m.preemptGen, 1)
 	atomic.Store(&gp.m.signalPending, 0)
 
-	if GOOS == "darwin" {
+	if GOOS == "darwin" || GOOS == "ios" {
 		atomic.Xadd(&pendingPreemptSignals, -1)
 	}
 }
@@ -363,18 +362,29 @@ const preemptMSupported = false
 // safe-point, it will preempt the goroutine. It always atomically
 // increments mp.preemptGen after handling a preemption request.
 func preemptM(mp *m) {
-	if GOOS == "darwin" && GOARCH == "arm64" && !iscgo {
-		// On darwin, we use libc calls, and cgo is required on ARM64
-		// so we have TLS set up to save/restore G during C calls. If cgo is
-		// absent, we cannot save/restore G in TLS, and if a signal is
-		// received during C execution we cannot get the G. Therefore don't
-		// send signals.
-		// This can only happen in the go_bootstrap program (otherwise cgo is
-		// required).
-		return
+	// On Darwin, don't try to preempt threads during exec.
+	// Issue #41702.
+	if GOOS == "darwin" || GOOS == "ios" {
+		execLock.rlock()
+	}
+
+	if atomic.Cas(&mp.signalPending, 0, 1) {
+		if GOOS == "darwin" || GOOS == "ios" {
+			atomic.Xadd(&pendingPreemptSignals, 1)
+		}
+
+		// If multiple threads are preempting the same M, it may send many
+		// signals to the same M such that it hardly make progress, causing
+		// live-lock problem. Apparently this could happen on darwin. See
+		// issue #37741.
+		// Only send a signal if there isn't already one pending.
+		// signalM(mp, sigPreempt)
+		throw("signalM not implemented")
+	}
+
+	if GOOS == "darwin" || GOOS == "ios" {
+		execLock.runlock()
 	}
-	// signalM(mp, sigPreempt)
-	throw("signalM not implemented")
 }
 
 // sigtrampgo is called from the signal handler function, sigtramp,
@@ -408,7 +418,7 @@ func sigtrampgo(sig uint32, info *_siginfo_t, ctx unsafe.Pointer) {
 			// no non-Go signal handler for sigPreempt.
 			// The default behavior for sigPreempt is to ignore
 			// the signal, so badsignal will be a no-op anyway.
-			if GOOS == "darwin" {
+			if GOOS == "darwin" || GOOS == "ios" {
 				atomic.Xadd(&pendingPreemptSignals, -1)
 			}
 			return
@@ -565,7 +575,7 @@ func sighandler(sig uint32, info *_siginfo_t, ctxt unsafe.Pointer, gp *g) {
 		print("signal arrived during cgo execution\n")
 		gp = _g_.m.lockedg.ptr()
 	}
-	if sig == _SIGILL {
+	if sig == _SIGILL || sig == _SIGFPE {
 		// It would be nice to know how long the instruction is.
 		// Unfortunately, that's complicated to do in general (mostly for x86
 		// and s930x, but other archs have non-standard instruction lengths also).
@@ -656,7 +666,7 @@ func sigpanic() {
 		}
 		// Support runtime/debug.SetPanicOnFault.
 		if g.paniconfault {
-			panicmem()
+			panicmemAddr(g.sigcode1)
 		}
 		print("unexpected fault address ", hex(g.sigcode1), "\n")
 		throw("fault")
@@ -666,7 +676,7 @@ func sigpanic() {
 		}
 		// Support runtime/debug.SetPanicOnFault.
 		if g.paniconfault {
-			panicmem()
+			panicmemAddr(g.sigcode1)
 		}
 		print("unexpected fault address ", hex(g.sigcode1), "\n")
 		throw("fault")
@@ -879,7 +889,7 @@ func badsignal(sig uintptr, c *sigctxt) {
 		exit(2)
 		*(*uintptr)(unsafe.Pointer(uintptr(123))) = 2
 	}
-	needm(0)
+	needm()
 	if !sigsend(uint32(sig)) {
 		// A foreign thread received the signal sig, and the
 		// Go code does not want to handle it.
@@ -922,7 +932,7 @@ func sigfwdgo(sig uint32, info *_siginfo_t, ctx unsafe.Pointer) bool {
 	// This function and its caller sigtrampgo assumes SIGPIPE is delivered on the
 	// originating thread. This property does not hold on macOS (golang.org/issue/33384),
 	// so we have no choice but to ignore SIGPIPE.
-	if GOOS == "darwin" && sig == _SIGPIPE {
+	if (GOOS == "darwin" || GOOS == "ios") && sig == _SIGPIPE {
 		return true
 	}