Do not count invocations but usage of a function, i.e., increment a function's counter at IC calls …

runtime/vm/code_generator.cc

 // Copyright (c) 2011, 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/code_generator.h"
 
 #include "vm/code_index_table.h"
 #include "vm/code_patcher.h"
 #include "vm/compiler.h"
 #include "vm/dart_api_impl.h"
 #include "vm/dart_entry.h"
 #include "vm/debugger.h"
 #include "vm/exceptions.h"
 #include "vm/object_store.h"
 #include "vm/resolver.h"
 #include "vm/runtime_entry.h"
 #include "vm/stack_frame.h"
 #include "vm/verifier.h"
 
 namespace dart {
 
 DEFINE_FLAG(bool, inline_cache, true, "enable inline caches");
 DEFINE_FLAG(bool, trace_deopt, false, "Trace deoptimization");
 DEFINE_FLAG(bool, trace_ic, false, "trace IC handling");
 DEFINE_FLAG(bool, trace_patching, false, "Trace patching of code.");
 DEFINE_FLAG(bool, trace_runtime_calls, false, "Trace runtime calls.");
+DEFINE_FLAG(int, optimization_counter_threshold, 2000,
+    "function's usage-counter value before it is optimized, -1 means never.");
+DECLARE_FLAG(bool, trace_type_checks);
+DECLARE_FLAG(bool, report_usage_count);
 DECLARE_FLAG(int, deoptimization_counter_threshold);
-DECLARE_FLAG(bool, trace_type_checks);
+
+
+bool CodeGenerator::CanOptimize() {
+  return
+      !FLAG_report_usage_count &&
+      (FLAG_optimization_counter_threshold >= 0) &&
+      !Isolate::Current()->debugger()->IsActive();
+}
 
 
 void CodeGenerator::DescriptorList::AddDescriptor(
     PcDescriptors::Kind kind,
     intptr_t pc_offset,
     intptr_t node_id,
     intptr_t token_index,
     intptr_t try_index) {
   struct PcDesc data;
   data.pc_offset = pc_offset;
@@ skipping 906 matching lines @@
 // Only unoptimized code has invocation counter threshold checking.
 // Once the invocation counter threshold is reached any entry into the
 // unoptimized code is redirected to this function.
 DEFINE_RUNTIME_ENTRY(OptimizeInvokedFunction, 1) {
   ASSERT(arguments.Count() ==
          kOptimizeInvokedFunctionRuntimeEntry.argument_count());
   const Function& function = Function::CheckedHandle(arguments.At(0));
   if (function.deoptimization_counter() >=
       FLAG_deoptimization_counter_threshold) {
     // TODO(srdjan): Investigate excessive deoptimization.
-    function.set_invocation_counter(0);
+    function.set_usage_counter(0);
+    return;
+  }
+  if (Code::Handle(function.code()).is_optimized()) {
+    // The caller has been already optimized.
+    // TODO(srdjan): This is a significant slowdown, the caller is probably in
+    // a loop. Maybe test if the code has been optimized before calling.
+    // If this happens from optimized code, then it means that the optimized
+    // code needs to be reoptimized.
+    function.set_usage_counter(0);
     return;
   }
   if (function.is_optimizable()) {
     ASSERT(!Code::Handle(function.code()).is_optimized());
     const Code& unoptimized_code = Code::Handle(function.code());
     // Compilation patches the entry of unoptimized code.
     const Error& error =
         Error::Handle(Compiler::CompileOptimizedFunction(function));
     if (!error.IsNull()) {
       Exceptions::PropagateError(error);
     }
     const Code& optimized_code = Code::Handle(function.code());
     ASSERT(!optimized_code.IsNull());
     ASSERT(!unoptimized_code.IsNull());
   } else {
     // TODO(5442338): Abort as this should not happen.
-    function.set_invocation_counter(0);
+    function.set_usage_counter(0);
   }
 }
 
 
 // The caller must be a static call in a Dart frame, or an entry frame.
 // Patch static call to point to 'new_entry_point'.
 DEFINE_RUNTIME_ENTRY(FixCallersTarget, 1) {
   ASSERT(arguments.Count() == kFixCallersTargetRuntimeEntry.argument_count());
   const Function& function = Function::CheckedHandle(arguments.At(0));
   ASSERT(!function.IsNull());
@@ skipping 71 matching lines @@
     const Class& cls = Class::Handle(function.owner());
     const Script& script = Script::Handle(cls.script());
     intptr_t line, column;
     script.GetTokenLocation(deopt_token_index, &line, &column);
     OS::Print("  Line: %d Column: %d ", line, column);
     OS::Print(">>  %s\n", String::Handle(script.GetLine(line)).ToCString());
   }
   caller_frame->set_pc(continue_at_pc);
   // Clear invocation counter so that the function gets optimized after
   // types/classes have been collected.
-  function.set_invocation_counter(0);
+  function.set_usage_counter(0);
   function.set_deoptimization_counter(function.deoptimization_counter() + 1);
 
   // We have to skip the following otherwise the compiler will complain
   // when it attempts to install unoptimized code into a function that
   // was already deoptimized.
   if (Code::Handle(function.code()).is_optimized()) {
     // Get unoptimized code. Compilation restores (reenables) the entry of
     // unoptimized code.
     const Error& error = Error::Handle(Compiler::CompileFunction(function));
     if (!error.IsNull()) {
@@ skipping 82 matching lines @@
       }
     }
   }
   // The cache is null terminated, therefore the loop above should never
   // terminate by itself.
   UNREACHABLE();
   return Code::null();
 }
 
 }  // namespace dart