proc/gdbserial: disable async preemption on macOS

Disables async preemption on macOS

Fixes #1905

pkg/proc/gdbserial/gdbserver.go

@@ -390,6 +390,10 @@ func LLDBLaunch(cmd []string, wd string, foreground bool, debugInfoDirs []string
 
 	process.SysProcAttr = sysProcAttr(foreground)
 
+	if runtime.GOOS == "darwin" {
+		process.Env = proc.DisableAsyncPreemptEnv()
+	}
+
 	err := process.Start()
 	if err != nil {
 		return nil, err
@@ -406,7 +410,7 @@ func LLDBLaunch(cmd []string, wd string, foreground bool, debugInfoDirs []string
 	if err != nil {
 		return nil, err
 	}
-	return proc.NewTarget(p, false), nil
+	return proc.NewTarget(p, runtime.GOOS == "darwin"), nil
 }
 
 // LLDBAttach starts an instance of lldb-server and connects to it, asking
@@ -655,7 +659,6 @@ continueLoop:
 		var err error
 		var sig uint8
 		tu.Reset()
-		//TODO: pass thread list to resume, which should use it to pass the correct signals
 		threadID, sig, err = p.conn.resume(p.threads, &tu)
 		if err != nil {
 			if _, exited := err.(proc.ErrProcessExited); exited {

pkg/proc/native/proc_windows.go

@@ -7,7 +7,6 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
-	"strings"
 	"syscall"
 	"unsafe"
 
@@ -56,14 +55,7 @@ func Launch(cmd []string, wd string, foreground bool, _ []string) (*proc.Target,
 	}
 	closer.Close()
 
-	env := os.Environ()
-	for i := range env {
-		if strings.HasPrefix(env[i], "GODEBUG=") {
-			// Go 1.14 asynchronous preemption mechanism is incompatible with
-			// debuggers, see: https://github.com/golang/go/issues/36494
-			env[i] += ",asyncpreemptoff=1"
-		}
-	}
+	env := proc.DisableAsyncPreemptEnv()
 
 	var p *os.Process
 	dbp := New(0)

pkg/proc/proc.go

@@ -7,8 +7,10 @@ import (
 	"go/ast"
 	"go/constant"
 	"go/token"
+	"os"
 	"path/filepath"
 	"strconv"
+	"strings"
 
 	"github.com/go-delve/delve/pkg/goversion"
 )
@@ -845,3 +847,17 @@ func setAsyncPreemptOff(p *Target, v int64) {
 	err = scope.setValue(asyncpreemptoffv, newConstant(constant.MakeInt64(v), scope.Mem), "")
 	logger.Warnf("could not set asyncpreemptoff %v", err)
 }
+
+// DisableAsyncPreemptEnv returns a process environment (like os.Environ)
+// where asyncpreemptoff is set to 1.
+func DisableAsyncPreemptEnv() []string {
+	env := os.Environ()
+	for i := range env {
+		if strings.HasPrefix(env[i], "GODEBUG=") {
+			// Go 1.14 asynchronous preemption mechanism is incompatible with
+			// debuggers, see: https://github.com/golang/go/issues/36494
+			env[i] += ",asyncpreemptoff=1"
+		}
+	}
+	return env
+}