Add --use_cha (default true, switch to false if you use dynamic class loading). Use CHA to specify …

runtime/vm/dart_api_impl.cc

Index: runtime/vm/dart_api_impl.cc
===================================================================
--- runtime/vm/dart_api_impl.cc	(revision 11068)
+++ runtime/vm/dart_api_impl.cc	(working copy)
@@ -32,6 +32,7 @@
 namespace dart {
 
 DECLARE_FLAG(bool, print_class_table);
+DECLARE_FLAG(bool, use_cha);
 
 ThreadLocalKey Api::api_native_key_ = Thread::kUnsetThreadLocalKey;
 
@@ -3741,11 +3742,42 @@
 }
 
 
+// Removes optimized code once we load more classes, since --use_cha based
+// optimizations may have become invalid.
+// TODO(srdjan): Note which functions use which CHA decision and deoptimize
+// only the necessary ones.
+static void RemoveOptimizedCode() {
+  ASSERT(FLAG_use_cha);
+  const ClassTable& class_table = *Isolate::Current()->class_table();
+  Class& cls = Class::Handle();
+  Array& array = Array::Handle();
+  Function& function = Function::Handle();
+  intptr_t num_cids = class_table.NumCids();

[regis, 2012/08/21 20:52:21]

const

[srdjan, 2012/08/21 22:08:15]

Done.

+  for (intptr_t i = kInstanceCid; i < num_cids; i++) {
+    if (!class_table.HasValidClassAt(i)) continue;
+    cls = class_table.At(i);
+    ASSERT(!cls.IsNull());
+    array = cls.functions();
+    intptr_t num_functions = array.IsNull() ? 0 : array.Length();
+    for (intptr_t f = 0; f < num_functions; f++) {
+      function ^= array.At(f);
+      ASSERT(!function.IsNull());
+      if (function.HasOptimizedCode()) {
+        function.SwitchToUnoptimizedCode();
+      }
+    }
+  }
+}
+
+
 DART_EXPORT Dart_Handle Dart_LoadScript(Dart_Handle url,
                                         Dart_Handle source) {
   TIMERSCOPE(time_script_loading);
   Isolate* isolate = Isolate::Current();
   DARTSCOPE(isolate);
+  if (FLAG_use_cha) {
+    RemoveOptimizedCode();
+  }

[siva, 2012/08/21 21:39:19]

These checks on every load library/script/source seem pretty heavy weight, do
you know what the impact on startup time is with this change?

Why not keep a flag in the isolate optimized_code_exists_, set it when optimized
code is generated and then you can skip RemoveOptimziedCode if
optimized_code_exists_ is false.
(that way it won't repeatedly call the loop too).

[srdjan, 2012/08/21 22:08:15]

No difference seen in CorelibIsolateStartup.

   const String& url_str = Api::UnwrapStringHandle(isolate, url);
   if (url_str.IsNull()) {
     RETURN_TYPE_ERROR(isolate, url, String);
@@ -3783,6 +3815,9 @@
   if (buffer == NULL) {
     RETURN_NULL_ERROR(buffer);
   }
+  if (FLAG_use_cha) {
+    RemoveOptimizedCode();
+  }
   const Snapshot* snapshot = Snapshot::SetupFromBuffer(buffer);
   if (!snapshot->IsScriptSnapshot()) {
     return Api::NewError("%s expects parameter 'buffer' to be a script type"
@@ -3947,6 +3982,9 @@
   TIMERSCOPE(time_script_loading);
   Isolate* isolate = Isolate::Current();
   DARTSCOPE(isolate);
+  if (FLAG_use_cha) {
+    RemoveOptimizedCode();
+  }
   const String& url_str = Api::UnwrapStringHandle(isolate, url);
   if (url_str.IsNull()) {
     RETURN_TYPE_ERROR(isolate, url, String);
@@ -4012,6 +4050,9 @@
   TIMERSCOPE(time_script_loading);
   Isolate* isolate = Isolate::Current();
   DARTSCOPE(isolate);
+  if (FLAG_use_cha) {
+    RemoveOptimizedCode();
+  }
   const Library& lib = Api::UnwrapLibraryHandle(isolate, library);
   if (lib.IsNull()) {
     RETURN_TYPE_ERROR(isolate, library, Library);