[vm, timeline] Fix compilation failed below macOS 10.14

signpost.h exists in macOS 10.14 or above, so compilation failed below macOS 10.14

Change-Id: I97c4d6652f8330d3fc150186e41067c80c3b56f2
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/151101
Commit-Queue: Vyacheslav Egorov <[email protected]>
Reviewed-by: Vyacheslav Egorov <[email protected]>

Author: pangzhen

runtime/vm/timeline.cc

@@ -117,9 +117,7 @@ static TimelineEventRecorder* CreateTimelineRecorder() {
 #if defined(HOST_OS_LINUX) || defined(HOST_OS_ANDROID)
       return new TimelineEventSystraceRecorder();
 #elif defined(HOST_OS_MACOS)
-      if (__builtin_available(iOS 12.0, macOS 10.14, *)) {
-        return new TimelineEventMacosRecorder();
-      }
+      return new TimelineEventMacosRecorder();
 #elif defined(HOST_OS_FUCHSIA)
       return new TimelineEventFuchsiaRecorder();
 #else
@@ -767,10 +765,8 @@ TimelineStream::TimelineStream(const char* name,
       enabled_(static_cast<uintptr_t>(enabled))
 #endif
 {
-#if defined(HOST_OS_MACOS)
-  if (__builtin_available(iOS 12.0, macOS 10.14, *)) {
-    macos_log_ = os_log_create("Dart", name);
-  }
+#if defined(HOST_OS_SUPPORTS_SIGNPOST)
+  macos_log_ = os_log_create("Dart", name);
 #endif
 }
 

runtime/vm/timeline.h

@@ -20,8 +20,14 @@
 #include <lib/trace-engine/instrumentation.h>
 #elif defined(HOST_OS_MACOS)
 #include <os/availability.h>
+#if defined(__MAC_10_14) || defined (__IPHONE_12_0)
+#define HOST_OS_SUPPORTS_SIGNPOST 1
+#endif
+//signpost.h exists in macOS 10.14, iOS 12 or above
+#if defined(HOST_OS_SUPPORTS_SIGNPOST)
 #include <os/signpost.h>
 #endif
+#endif
 
 namespace dart {
 
@@ -94,7 +100,7 @@ class TimelineStream {
 
 #if defined(HOST_OS_FUCHSIA)
   trace_site_t* trace_site() { return &trace_site_; }
-#elif defined(HOST_OS_MACOS)
+#elif defined(HOST_OS_SUPPORTS_SIGNPOST)
   os_log_t macos_log() { return macos_log_; }
 #endif
 
@@ -108,7 +114,7 @@ class TimelineStream {
 
 #if defined(HOST_OS_FUCHSIA)
   trace_site_t trace_site_ = {};
-#elif defined(HOST_OS_MACOS)
+#elif defined(HOST_OS_SUPPORTS_SIGNPOST)
   os_log_t macos_log_ = {};
 #endif
 };

runtime/vm/timeline_macos.cc

@@ -5,11 +5,14 @@
 #include "vm/globals.h"
 #if defined(HOST_OS_MACOS) && defined(SUPPORT_TIMELINE)
 
-#include <os/signpost.h>
 
 #include "vm/log.h"
 #include "vm/timeline.h"
 
+#if defined(HOST_OS_SUPPORTS_SIGNPOST)
+#include <os/signpost.h>
+#endif
+
 namespace dart {
 
 // Only available on iOS 12.0, macOS 10.14 or above
@@ -23,6 +26,7 @@ void TimelineEventMacosRecorder::OnEvent(TimelineEvent* event) {
     return;
   }
 
+#if defined(HOST_OS_SUPPORTS_SIGNPOST)
   os_log_t log = event->stream_->macos_log();
   if (!os_signpost_enabled(log)) {
     return;
@@ -75,6 +79,7 @@ void TimelineEventMacosRecorder::OnEvent(TimelineEvent* event) {
     default:
       break;
   }
+#endif  // defined(HOST_OS_SUPPORTS_SIGNPOST)
 }
 
 }  // namespace dart