Deoptimization can occur at Dart calls (includes native calls to C) but not at runtime calls. This …

runtime/vm/code_generator.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/code_generator.h"
 
 #include "vm/assembler_macros.h"
 #include "vm/ast.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/deopt_instructions.h"
 #include "vm/exceptions.h"
 #include "vm/intermediate_language.h"
 #include "vm/object_store.h"
 #include "vm/message.h"
 #include "vm/message_handler.h"
 #include "vm/parser.h"
 #include "vm/resolver.h"
 #include "vm/runtime_entry.h"
 #include "vm/stack_frame.h"
 #include "vm/symbols.h"
 #include "vm/verifier.h"
 
 namespace dart {
 
+DEFINE_FLAG(bool, deoptimize_alot, false,
+    "Deoptimizes all live frames at runtime and native entries.");

[siva, 2012/08/30 01:37:30]

Deoptimizes all live frames when we are about to return to dart code from
runtime and native entries?

[srdjan, 2012/08/30 17:16:16]

Done, removed reference to runtime.

 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, enable_type_checks);
 DECLARE_FLAG(bool, trace_type_checks);
 DECLARE_FLAG(bool, report_usage_count);
@@ skipping 1349 matching lines @@
       *deopt_index = descriptors.DeoptIndex(i);
       return;
     }
   }
   *deopt_id = Isolate::kNoDeoptId;
   *deopt_reason = kDeoptUnknown;
   *deopt_index = -1;
 }
 
 
+// Currently checks only that all optimized frames have kDeoptIndex
+//  and unoptimized code has the kDeoptAfter.
+void DeoptimizeAll() {
+  DartFrameIterator iterator;
+  StackFrame* frame = iterator.NextFrame();

[siva, 2012/08/30 01:37:30]

Code& optimized_code = Code::Handle();
Function& function = Function::Handle();
Code& unoptimized_code = Code::Handle();

[srdjan, 2012/08/30 17:16:16]

Done.

+  while (frame != NULL) {
+    const Code& optimized_code = Code::Handle(frame->LookupDartCode());

[siva, 2012/08/30 01:37:30]

optimized_code = frame->LookupDartCode();

[srdjan, 2012/08/30 17:16:16]

Done.

+    if (optimized_code.is_optimized()) {
+      intptr_t deopt_id, deopt_reason, deopt_index;
+      GetDeoptIxDescrAtPc(optimized_code, frame->pc(),
+                          &deopt_id, &deopt_reason, &deopt_index);
+      ASSERT(deopt_id != Isolate::kNoDeoptId);
+      const Function& function = Function::Handle(optimized_code.function());

[siva, 2012/08/30 01:37:30]

function = optimized_code.function();
unoptimized_code = function.unoptimzied_code();

[srdjan, 2012/08/30 17:16:16]

Done.

+      const Code& unoptimized_code = Code::Handle(function.unoptimized_code());
+      ASSERT(!unoptimized_code.IsNull());
+      uword continue_at_pc =
+          unoptimized_code.GetDeoptAfterPcAtDeoptId(deopt_id);
+      ASSERT(continue_at_pc != 0);

[siva, 2012/08/30 01:37:30]

Maybe also assert that
continue_at_pc > unoptimized_code.EntryPoint() &&
continue_at_pc < (unoptimized_code.EntryPoint() + unoptimized_code.Size())

[srdjan, 2012/08/30 17:16:16]

This check belongs in GetDeoptAfterPcAtDeoptId. Adding it there.

+    }
+    frame = iterator.NextFrame();
+  }
+}
+
 
 // Copy saved registers into the isolate buffer.
 static void CopySavedRegisters(intptr_t* saved_registers_address) {
   intptr_t* registers_copy = new intptr_t[kNumberOfCpuRegisters];
   ASSERT(registers_copy != NULL);
   ASSERT(saved_registers_address != NULL);
   for (intptr_t i = 0; i < kNumberOfCpuRegisters; i++) {
     registers_copy[i] = *saved_registers_address;
     saved_registers_address++;
   }
@@ skipping 148 matching lines @@
   ASSERT(!optimized_code.IsNull() && optimized_code.is_optimized());
   ASSERT(!unoptimized_code.IsNull() && !unoptimized_code.is_optimized());
 
   intptr_t* frame_copy = isolate->deopt_frame_copy();
   intptr_t* registers_copy = isolate->deopt_registers_copy();
 
   intptr_t deopt_id, deopt_reason, deopt_index;
   GetDeoptIxDescrAtPc(optimized_code, caller_frame->pc(),
                       &deopt_id, &deopt_reason, &deopt_index);
   ASSERT(deopt_id != Isolate::kNoDeoptId);
-  uword continue_at_pc = unoptimized_code.GetDeoptPcAtDeoptId(deopt_id);
+  uword continue_at_pc = unoptimized_code.GetDeoptBeforePcAtDeoptId(deopt_id);

[siva, 2012/08/30 01:37:30]

I am a little confused I thought unoptimized_code should only have DeoptAfter
entries?

[srdjan, 2012/08/30 17:16:16]

DeoptBefore an DeoptAfter are continuation points in unoptimized code. Added
more asserts that we can add them only to unoptimized code.
DeoptIndex can be added only to optimized code.

   if (FLAG_trace_deopt) {
     OS::Print("  -> continue at 0x%x\n", continue_at_pc);
     // TODO(srdjan): If we could allow GC, we could print the line where
     // deoptimization occured.
   }
   const Array& deopt_info_array =
       Array::Handle(optimized_code.deopt_info_array());
   ASSERT(!deopt_info_array.IsNull());
   DeoptInfo& deopt_info = DeoptInfo::Handle();
   deopt_info ^= deopt_info_array.At(deopt_index);
@@ skipping 30 matching lines @@
   function.set_usage_counter(0);
   function.set_deoptimization_counter(function.deoptimization_counter() + 1);
 
   if (function.HasOptimizedCode()) {
     function.SwitchToUnoptimizedCode();
   }
 }
 END_LEAF_RUNTIME_ENTRY
 
 }  // namespace dart