Remove saving/restoring of the context at function entry.

runtime/vm/debugger.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/debugger.h"
 
 #include "include/dart_api.h"
 
 #include "vm/code_generator.h"
 #include "vm/code_patcher.h"
@@ skipping 454 matching lines @@
   for (intptr_t i = 0; i < var_desc_len; i++) {
     RawLocalVarDescriptors::VarInfo var_info;
     var_descriptors_.GetInfo(i, &var_info);
     const int8_t kind = var_info.kind();
     if (kind == RawLocalVarDescriptors::kSavedCurrentContext) {
       if (FLAG_trace_debugger_stacktrace) {
         OS::PrintErr("\tFound saved current ctx at index %d\n",
             var_info.index());
       }
       ASSERT(Object::Handle(GetLocalVar(var_info.index())).IsContext());
-      return reinterpret_cast<RawContext*>(GetLocalVar(var_info.index()));
+      return Context::RawCast(GetLocalVar(var_info.index()));
     }
   }
   UNREACHABLE();
   return Context::null();
 }
 
 
 const char* DebuggerEvent::EventTypeToCString(EventType type) {
   switch (type) {
     case kBreakpointReached:
@@ skipping 705 matching lines @@
                                             uword pc,
                                             StackFrame* frame,
                                             const Code& code,
                                             const Array& deopt_frame,
                                             intptr_t deopt_frame_offset) {
   ASSERT(code.ContainsInstructionAt(pc));
   ActivationFrame* activation =
       new ActivationFrame(pc, frame->fp(), frame->sp(), code,
                           deopt_frame, deopt_frame_offset);
 
-  // Is there a closure call at the current PC?
-  bool is_closure_call = false;
-  const PcDescriptors& pc_desc =
-      PcDescriptors::Handle(isolate, code.pc_descriptors());
-  PcDescriptors::Iterator iter(pc_desc, RawPcDescriptors::kClosureCall);
-  while (iter.MoveNext()) {
-    if (iter.Pc() == pc) {
-      is_closure_call = true;
-      break;
-    }
-  }
-
   // Recover the context for this frame.
-  if (is_closure_call) {
-    // If the callee is a closure, we should have stored the context
-    // in the current frame before making the call.
-    const Context& closure_call_ctx =
-        Context::Handle(isolate, activation->GetSavedCurrentContext());
-    ASSERT(!closure_call_ctx.IsNull());
-    activation->SetContext(closure_call_ctx);
-    if (FLAG_trace_debugger_stacktrace) {
-      OS::PrintErr("\tUsing closure call ctx: %s\n",
-                   closure_call_ctx.ToCString());
-    }
-  } else {
-    const Context& ctx =
-        Context::Handle(isolate, activation->GetSavedCurrentContext());
-    ASSERT(!ctx.IsNull());
-    activation->SetContext(ctx);
-    if (FLAG_trace_debugger_stacktrace) {
-      OS::PrintErr("\tUsing entry ctx: %s\n", ctx.ToCString());
-    }
+  const Context& ctx =
+      Context::Handle(isolate, activation->GetSavedCurrentContext());
+  ASSERT(!ctx.IsNull());
+  activation->SetContext(ctx);
+  if (FLAG_trace_debugger_stacktrace) {
+    OS::PrintErr("\tUsing saved context: %s\n", ctx.ToCString());
   }
   if (FLAG_trace_debugger_stacktrace) {
     OS::PrintErr("\tLine number: %" Pd "\n", activation->LineNumber());
   }
   return activation;
 }
 
 
 RawArray* Debugger::DeoptimizeToArray(Isolate* isolate,
                                       StackFrame* frame,
@@ skipping 1267 matching lines @@
 }
 
 
 void Debugger::RegisterCodeBreakpoint(CodeBreakpoint* bpt) {
   ASSERT(bpt->next() == NULL);
   bpt->set_next(code_breakpoints_);
   code_breakpoints_ = bpt;
 }
 
 }  // namespace dart