Copy ICData descriptors when starting background compilation, so that they do not change while comp…

runtime/vm/compiler.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/compiler.h"
 
 #include "vm/assembler.h"
 
 #include "vm/ast_printer.h"
 #include "vm/block_scheduler.h"
@@ skipping 166 matching lines @@
   const Function& function = Function::CheckedHandle(arguments.ArgAt(0));
   ASSERT(!function.HasCode());
   const Error& error =
       Error::Handle(Compiler::CompileFunction(thread, function));
   if (!error.IsNull()) {
     Exceptions::PropagateError(error);
   }
 }
 
 
+bool Compiler::IsBackgroundCompilation() {
+  // For now: compilation in non mutator thread is the background compoilation.
+  return !Thread::Current()->IsMutatorThread();
+}
+
+
 RawError* Compiler::Compile(const Library& library, const Script& script) {
   LongJumpScope jump;
   if (setjmp(*jump.Set()) == 0) {
     Thread* const thread = Thread::Current();
     StackZone zone(thread);
     if (FLAG_trace_compiler) {
       const String& script_url = String::Handle(script.url());
       // TODO(iposva): Extract script kind.
       THR_Print("Compiling %s '%s'\n", "", script_url.ToCString());
     }
@@ skipping 223 matching lines @@
       // LongJump.
       {
         CSTAT_TIMER_SCOPE(thread, graphbuilder_timer);
         ZoneGrowableArray<const ICData*>* ic_data_array =
             new(zone) ZoneGrowableArray<const ICData*>();
         if (optimized) {
           // Extract type feedback before the graph is built, as the graph
           // builder uses it to attach it to nodes.
           ASSERT(function.deoptimization_counter() <
                  FLAG_deoptimization_counter_threshold);
-          function.RestoreICDataMap(ic_data_array);
+
+          // 'Freeze' ICData in background compilation so that it does not
+          // change while compiling.
+          const bool clone_descriptors = Compiler::IsBackgroundCompilation();
+          function.RestoreICDataMap(ic_data_array, clone_descriptors);
+
           if (FLAG_print_ic_data_map) {
             for (intptr_t i = 0; i < ic_data_array->length(); i++) {
               if ((*ic_data_array)[i] != NULL) {
                 THR_Print("%" Pd " ", i);
                 FlowGraphPrinter::PrintICData(*(*ic_data_array)[i]);
               }
             }
           }
         }
 
@@ skipping 1089 matching lines @@
                                                function,
                                                Compiler::kNoOSRDeoptId,
                                                &code));
         // TODO(srdjan): We do not expect errors while compiling optimized
         // code, any errors should have been caught when compiling
         // unoptimized code.
         // If it still happens mark function as not optimizable.
         ASSERT(error.IsNull());
         temp_function = RemoveFunctionOrNull();
         ASSERT(temp_function.raw() == function.raw());
-        // Reset to 0 so that it can be recompiled if needed.
-        function.set_usage_counter(0);
         function = LastFunctionOrNull();
+        ASSERT(!code.IsNull());
         AddCode(code);
       }
     }
     Thread::ExitIsolateAsHelper();
     {
       // Wait to be notified when the work queue is not empty.
       MonitorLocker ml(queue_monitor_);
       while ((function_queue_length() == 0) && running_) {
         ml.Wait();
       }
@@ skipping 15 matching lines @@
 
 void BackgroundCompiler::InstallGeneratedCode() {
   MonitorLocker ml(queue_monitor_);
   CompilationWorkQueue queue(CodesQueue());
   Code& code = Code::Handle();
   Object& owner = Object::Handle();
   for (intptr_t i = 0; i < queue.Length(); i++) {
     code = queue.PopBackCode();
     if (code.IsDisabled()) continue;
     owner = code.owner();
-    ASSERT(owner.IsFunction());
-    Function::Cast(owner).InstallOptimizedCode(code, false /* not OSR */);
+    const Function& function = Function::Cast(owner);
+    function.InstallOptimizedCode(code, false /* not OSR */);
+    if (function.usage_counter() < 0) {
+      // Reset to 0 so that it can be recompiled if needed.
+      function.set_usage_counter(0);
+    }
   }
 }
 
 
 GrowableObjectArray* BackgroundCompiler::FunctionsQueue() const {
   return
       &GrowableObjectArray::ZoneHandle(isolate_->compilation_function_queue());
 }
 
 
@@ skipping 80 matching lines @@
           thread->zone(), GrowableObjectArray::New()));
       start_task = true;
     }
   }
   if (start_task) {
     Dart::thread_pool()->Run(isolate->background_compiler());
   }
 }
 
 }  // namespace dart