Replace ChainContextInstr with existing IL instructions.

runtime/vm/flow_graph_builder.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/flow_graph_builder.h"
 
 #include "lib/invocation_mirror.h"
 #include "vm/ast_printer.h"
 #include "vm/bit_vector.h"
 #include "vm/code_descriptors.h"
@@ skipping 3076 matching lines @@
       (scope != NULL) ? scope->num_context_variables() : 0;
   int previous_context_level = owner()->context_level();
   if (num_context_variables > 0) {
     InlineBailout("EffectGraphVisitor::VisitSequenceNode (context)");
     // The loop local scope declares variables that are captured.
     // Allocate and chain a new context.
     // Allocate context computation (uses current CTX)
     Value* allocated_context =
         Bind(new AllocateContextInstr(node->token_pos(),
                                       num_context_variables));
-
-    // If this node_sequence is the body of the function being compiled, and if
-    // this function allocates context variables, but none of its enclosing
-    // functions do, the context on entry is not linked as parent of the
-    // allocated context but saved on entry and restored on exit as to prevent
-    // memory leaks.
-    // In this case, the parser pre-allocates a variable to save the context.
-    if (MustSaveRestoreContext(node)) {
+    { LocalVariable* tmp_var = EnterTempLocalScope(allocated_context);
+      // If this node_sequence is the body of the function being compiled, and
+      // if this function allocates context variables, but none of its enclosing
+      // functions do, the context on entry is not linked as parent of the
+      // allocated context but saved on entry and restored on exit as to prevent
+      // memory leaks.
+      // In this case, the parser pre-allocates a variable to save the context.
+      if (MustSaveRestoreContext(node)) {
+        Value* current_context = Bind(new CurrentContextInstr());
+        Do(BuildStoreTemp(
+            *owner()->parsed_function()->saved_entry_context_var(),
+            current_context));
+        Value* null_context = Bind(new ConstantInstr(Object::ZoneHandle()));
+        AddInstruction(new StoreContextInstr(null_context));
+      }
       Value* current_context = Bind(new CurrentContextInstr());
-      Do(BuildStoreTemp(*owner()->parsed_function()->saved_entry_context_var(),
-                        current_context));
-      Value* null_context = Bind(new ConstantInstr(Object::ZoneHandle()));
-      AddInstruction(new StoreContextInstr(null_context));
+      Value* tmp_val = Bind(new LoadLocalInstr(*tmp_var));
+      Do(new StoreVMFieldInstr(tmp_val,
+                               Context::parent_offset(),
+                               current_context,
+                               Type::ZoneHandle()));
+      AddInstruction(
+          new StoreContextInstr(Bind(ExitTempLocalScope(tmp_var))));
     }
-
-    AddInstruction(new ChainContextInstr(allocated_context));
     owner()->set_context_level(scope->context_level());
 
     // If this node_sequence is the body of the function being compiled, copy
     // the captured parameters from the frame into the context.
     if (node == owner()->parsed_function()->node_sequence()) {
       ASSERT(scope->context_level() == 1);
       const Function& function = owner()->parsed_function()->function();
       const int num_params = function.NumParameters();
       int param_frame_index = (num_params == function.num_fixed_parameters()) ?
           (kParamEndSlotFromFp + num_params) : kFirstLocalSlotFromFp;
@@ skipping 423 matching lines @@
   intptr_t len = OS::SNPrint(NULL, 0, kFormat, function_name, reason) + 1;
   char* chars = Isolate::Current()->current_zone()->Alloc<char>(len);
   OS::SNPrint(chars, len, kFormat, function_name, reason);
   const Error& error = Error::Handle(
       LanguageError::New(String::Handle(String::New(chars))));
   Isolate::Current()->long_jump_base()->Jump(1, error);
 }
 
 
 }  // namespace dart