Move generate_perf_events_symbols flag to VM (new issue with @google address)

runtime/vm/code_observers.cc

Index: runtime/vm/code_observers.cc
diff --git a/runtime/vm/code_observers.cc b/runtime/vm/code_observers.cc
index c537febce943c7edcc0d7f506a39a7f49c3fa8ec..f8bac19603bfad5ae901f958692b49e2b17b662d 100644
--- a/runtime/vm/code_observers.cc
+++ b/runtime/vm/code_observers.cc
@@ -16,6 +16,8 @@ namespace dart {
 
 DEFINE_FLAG(bool, generate_gdb_symbols, false,
     "Generate symbols of generated dart functions for debugging with GDB");
+DEFINE_FLAG(bool, generate_perf_events_symbols, false,
+    "Generate events symbols for profiling with perf");
 
 intptr_t CodeObservers::observers_length_ = 0;
 CodeObserver** CodeObservers::observers_ = NULL;
@@ -56,8 +58,34 @@ bool CodeObservers::AreActive() {
 
 class PerfCodeObserver : public CodeObserver {
  public:
+  PerfCodeObserver() {
+    Dart_FileOpenCallback file_open = Isolate::file_open_callback();
+    if (file_open == NULL) {
+      return;
+    }
+// TODO(7321): Move OS-specific code for perf profiling to the OS abstraction
+#if defined(TARGET_OS_LINUX)
+    const char* format = "/tmp/perf-%ld.map";
+    intptr_t pid = getpid();
+    intptr_t len = OS::SNPrint(NULL, 0, format, pid);
+    char* filename = new char[len + 1];
+    OS::SNPrint(filename, len + 1, format, pid);
+    out_file_ = (*file_open)(filename);
+#endif
+  }
+
+  // Not currently being called
+  ~PerfCodeObserver() {
+    Dart_FileCloseCallback file_close = Isolate::file_close_callback();
+    if (file_close == NULL) {
+      return;
+    }
+    ASSERT(out_file_ != NULL);
+    (*file_close)(out_file_);
+  }
+
   virtual bool IsActive() const {
-    return Dart::perf_events_file() != NULL;
+    return FLAG_generate_perf_events_symbols;
   }
 
   virtual void Notify(const char* name,
@@ -65,17 +93,19 @@ class PerfCodeObserver : public CodeObserver {
                       uword prologue_offset,
                       uword size,
                       bool optimized) {
+    Dart_FileWriteCallback file_write = Isolate::file_write_callback();
+    ASSERT(file_write != NULL);
     const char* format = "%"Px" %"Px" %s%s\n";
     const char* marker = optimized ? "*" : "";
     intptr_t len = OS::SNPrint(NULL, 0, format, base, size, marker, name);
     char* buffer = Isolate::Current()->current_zone()->Alloc<char>(len + 1);
     OS::SNPrint(buffer, len + 1, format, base, size, marker, name);
-    Dart_FileWriteCallback file_write = Isolate::file_write_callback();
-    ASSERT(file_write != NULL);
-    void* file = Dart::perf_events_file();
-    ASSERT(file != NULL);
-    (*file_write)(buffer, len, file);
+    ASSERT(out_file_ != NULL);
+    (*file_write)(buffer, len, out_file_);
   }
+
+ private:
+  void* out_file_;
 };
 
 
@@ -131,7 +161,10 @@ class GdbCodeObserver : public CodeObserver {
 
 
 void CodeObservers::InitOnce() {
-  Register(new PerfCodeObserver);
+// TODO(7321): Move flag registration to the OS abstraction
+  if (FLAG_generate_perf_events_symbols) {
+    Register(new PerfCodeObserver);
+  }
   Register(new PprofCodeObserver);
   Register(new GdbCodeObserver);
 #if defined(DART_VTUNE_SUPPORT)