Generate smaller unoptimized code for certain expressions.

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/class_finalizer.h"
@@ skipping 2088 matching lines @@
     Append(for_value);
     Value* temp_val = for_value.value();
     node->TempAt(i)->set_index(GetCurrentTempLocalIndex());
     Do(new PushTempInstr(temp_val));
     owner()->AllocateTemp();
   }
 }
 
 
 void EffectGraphVisitor::VisitLetNode(LetNode* node) {
+  BuildLetTempExpressions(node);
+
+  // Visit body.
+  for (intptr_t i = 0; i < node->nodes().length(); ++i) {
+    EffectGraphVisitor for_effect(owner());
+    node->nodes()[i]->Visit(&for_effect);
+    Append(for_effect);
+  }
+
   intptr_t num_temps = node->num_temps();
   if (num_temps > 0) {
-    BuildLetTempExpressions(node);
-    // TODO(fschneider): Generate better code for effect context by visiting the
-    // body for effect. Currently, the value of the body expression is
-    // materialized and then dropped. This also requires changing DropTempsInstr
-    // to have zero or one inputs.
-
-    // Visit body.
-    for (intptr_t i = 0; i < node->nodes().length() - 1; ++i) {
-      EffectGraphVisitor for_effect(owner());
-      node->nodes()[i]->Visit(&for_effect);
-      Append(for_effect);
-    }
-    // Visit the last body expression for value.
-    ValueGraphVisitor for_value(owner());
-    node->nodes().Last()->Visit(&for_value);
-    Append(for_value);
-    Value* result_value = for_value.value();
     owner()->DeallocateTemps(num_temps);
-    Do(new DropTempsInstr(num_temps, result_value));
-  } else {
-    ASSERT(num_temps == 0);
-    for (intptr_t i = 0; i < node->nodes().length(); ++i) {
-      EffectGraphVisitor for_effect(owner());
-      node->nodes()[i]->Visit(&for_effect);
-      Append(for_effect);
-    }
+    Do(new DropTempsInstr(num_temps));
   }
 }
 
 
 void ValueGraphVisitor::VisitLetNode(LetNode* node) {
   BuildLetTempExpressions(node);
 
   // Visit body.
   for (intptr_t i = 0; i < node->nodes().length() - 1; ++i) {
     EffectGraphVisitor for_effect(owner());
@@ skipping 1755 matching lines @@
                                   LanguageError::kError,
                                   Heap::kNew,
                                   "FlowGraphBuilder Bailout: %s %s",
                                   String::Handle(function.name()).ToCString(),
                                   reason));
   Isolate::Current()->long_jump_base()->Jump(1, error);
 }
 
 
 }  // namespace dart