all: remove scattered remnants of darwin/arm

This removes all conditions and conditional code (that I could find)
that depended on darwin/arm.

Fixes #35439 (since that only happened on darwin/arm)
Fixes #37611.

Change-Id: Ia4c32a5a4368ed75231075832b0b5bfb1ad11986
Reviewed-on: https://go-review.googlesource.com/c/go/+/227198
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

8 files changed, 13 insertions, 19 deletions

diff --git a/src/runtime/cgo/cgo.go b/src/runtime/cgo/cgo.go
index 5b3c701309..c02b837978 100644
--- a/src/runtime/cgo/cgo.go
+++ b/src/runtime/cgo/cgo.go
@@ -11,8 +11,7 @@ package cgo
 
 /*
 
-#cgo darwin,!arm,!arm64 LDFLAGS: -lpthread
-#cgo darwin,arm LDFLAGS: -framework CoreFoundation
+#cgo darwin,!arm64 LDFLAGS: -lpthread
 #cgo darwin,arm64 LDFLAGS: -framework CoreFoundation
 #cgo dragonfly LDFLAGS: -lpthread
 #cgo freebsd LDFLAGS: -lpthread
diff --git a/src/runtime/cgo/gcc_darwin_arm64.c b/src/runtime/cgo/gcc_darwin_arm64.c
index e6e305789f..fd7d4084c9 100644
--- a/src/runtime/cgo/gcc_darwin_arm64.c
+++ b/src/runtime/cgo/gcc_darwin_arm64.c
@@ -94,7 +94,7 @@ threadentry(void *v)
 }
 
 // init_working_dir sets the current working directory to the app root.
-// By default darwin/arm processes start in "/".
+// By default darwin/arm64 processes start in "/".
 static void
 init_working_dir()
 {
diff --git a/src/runtime/os_darwin.go b/src/runtime/os_darwin.go
index c11fbec0a5..01c40b4813 100644
--- a/src/runtime/os_darwin.go
+++ b/src/runtime/os_darwin.go
@@ -289,9 +289,9 @@ func mpreinit(mp *m) {
 // Called to initialize a new m (including the bootstrap m).
 // Called on the new thread, cannot allocate memory.
 func minit() {
-	// The alternate signal stack is buggy on arm and arm64.
+	// The alternate signal stack is buggy on arm64.
 	// The signal handler handles it directly.
-	if GOARCH != "arm" && GOARCH != "arm64" {
+	if GOARCH != "arm64" {
 		minitSignalStack()
 	}
 	minitSignalMask()
@@ -301,9 +301,9 @@ func minit() {
 // Called from dropm to undo the effect of an minit.
 //go:nosplit
 func unminit() {
-	// The alternate signal stack is buggy on arm and arm64.
+	// The alternate signal stack is buggy on arm64.
 	// See minit.
-	if GOARCH != "arm" && GOARCH != "arm64" {
+	if GOARCH != "arm64" {
 		unminitSignals()
 	}
 }
diff --git a/src/runtime/pprof/pprof_test.go b/src/runtime/pprof/pprof_test.go
index 83b3152d68..e78f1a4938 100644
--- a/src/runtime/pprof/pprof_test.go
+++ b/src/runtime/pprof/pprof_test.go
@@ -226,7 +226,7 @@ func testCPUProfile(t *testing.T, matches matchFunc, need []string, avoid []stri
 	switch runtime.GOOS {
 	case "darwin":
 		switch runtime.GOARCH {
-		case "arm", "arm64":
+		case "arm64":
 			// nothing
 		default:
 			out, err := exec.Command("uname", "-a").CombinedOutput()
diff --git a/src/runtime/signal_arm.go b/src/runtime/signal_arm.go
index 1663d913c3..e1d19244a9 100644
--- a/src/runtime/signal_arm.go
+++ b/src/runtime/signal_arm.go
@@ -63,9 +63,7 @@ func (c *sigctxt) preparePanic(sig uint32, gp *g) {
 	c.set_pc(uint32(funcPC(sigpanic)))
 }
 
-// TODO(issue 35439): enabling async preemption causes failures on darwin/arm.
-// Disable for now.
-const pushCallSupported = GOOS != "darwin"
+const pushCallSupported = true
 
 func (c *sigctxt) pushCall(targetPC uintptr) {
 	// Push the LR to stack, as we'll clobber it in order to
diff --git a/src/runtime/signal_unix.go b/src/runtime/signal_unix.go
index b8f27d1147..5dbfbaf4b1 100644
--- a/src/runtime/signal_unix.go
+++ b/src/runtime/signal_unix.go
@@ -350,8 +350,8 @@ func preemptM(mp *m) {
 		// yet, so doSigPreempt won't work.
 		return
 	}
-	if GOOS == "darwin" && (GOARCH == "arm" || GOARCH == "arm64") && !iscgo {
-		// On darwin, we use libc calls, and cgo is required on ARM and ARM64
+	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
@@ -1191,7 +1191,7 @@ func signalstack(s *stack) {
 	sigaltstack(&st, nil)
 }
 
-// setsigsegv is used on darwin/arm{,64} to fake a segmentation fault.
+// setsigsegv is used on darwin/arm64 to fake a segmentation fault.
 //
 // This is exported via linkname to assembly in runtime/cgo.
 //
diff --git a/src/runtime/tls_arm.s b/src/runtime/tls_arm.s
index bed7891368..e42de8deb4 100644
--- a/src/runtime/tls_arm.s
+++ b/src/runtime/tls_arm.s
@@ -17,14 +17,11 @@
 // Note: both functions will clobber R0 and R11 and
 // can be called from 5c ABI code.
 
-// On android and darwin, runtime.tls_g is a normal variable.
+// On android, runtime.tls_g is a normal variable.
 // TLS offset is computed in x_cgo_inittls.
 #ifdef GOOS_android
 #define TLSG_IS_VARIABLE
 #endif
-#ifdef GOOS_darwin
-#define TLSG_IS_VARIABLE
-#endif
 
 // save_g saves the g register into pthread-provided
 // thread-local memory, so that we can call externally compiled
diff --git a/src/runtime/vlrt.go b/src/runtime/vlrt.go
index f790d3b17f..e4d1be5d8a 100644
--- a/src/runtime/vlrt.go
+++ b/src/runtime/vlrt.go
@@ -132,7 +132,7 @@ func uint64mod(n, d uint64) uint64 {
 
 //go:nosplit
 // nosplit because division is used in syscall context in nanotime on darwin/386
-// and darwin/arm where stack splits are not allowed.
+// where stack splits are not allowed.
 func int64div(n, d int64) int64 {
 	// Check for 32 bit operands
 	if int64(int32(n)) == n && int64(int32(d)) == d {