Eliminate the type distinction between BindInstr and DoInstr.

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 "vm/ast_printer.h"
 #include "vm/bit_vector.h"
 #include "vm/code_descriptors.h"
 #include "vm/dart_entry.h"
@@ skipping 47 matching lines @@
     exit()->set_successor(other_fragment.entry());
     exit_ = other_fragment.exit();
   }
   temp_index_ = other_fragment.temp_index();
 }
 
 
 UseVal* EffectGraphVisitor::Bind(Computation* computation) {
   ASSERT(is_open());
   DeallocateTempIndex(computation->InputCount());
-  BindInstr* bind_instr = new BindInstr(computation);
+  BindInstr* bind_instr = new BindInstr(BindInstr::kUsed, computation);
   bind_instr->set_temp_index(AllocateTempIndex());
   if (is_empty()) {
     entry_ = bind_instr;
   } else {
     exit()->set_successor(bind_instr);
   }
   exit_ = bind_instr;
   return new UseVal(bind_instr);
 }
 
 
 void EffectGraphVisitor::Do(Computation* computation) {
   ASSERT(is_open());
   DeallocateTempIndex(computation->InputCount());
-  DoInstr* do_instr = new DoInstr(computation);
+  BindInstr* do_instr = new BindInstr(BindInstr::kUnused, computation);
   if (is_empty()) {
     entry_ = do_instr;
   } else {
     exit()->set_successor(do_instr);
   }
   exit_ = do_instr;
 }
 
 
 void EffectGraphVisitor::AddInstruction(Instruction* instruction) {
   ASSERT(is_open());
-  ASSERT(!instruction->IsDo());
-  ASSERT(!instruction->IsBind());
+  ASSERT(!instruction->IsDefinition());
   DeallocateTempIndex(instruction->InputCount());
   if (instruction->IsDefinition()) {
     instruction->AsDefinition()->set_temp_index(AllocateTempIndex());
   }
   if (is_empty()) {
     entry_ = exit_ = instruction;
   } else {
     exit()->set_successor(instruction);
     exit_ = instruction;
   }
@@ skipping 2435 matching lines @@
         // environment.
         Computation* comp = v->AsUse()->definition()->AsBind()->computation();
         intptr_t index = comp->AsStoreLocal()->local().BitIndexIn(var_count);
         current->SetInputAt(i, CopyValue((*env)[index]));
       }
     }
 
     // 2b. Handle LoadLocal and StoreLocal.
     // For each LoadLocal: Remove it from the graph.
     // For each StoreLocal: Remove it from the graph and update the environment.
-    ASSERT(!current->IsDo() ||
-           !current->AsDo()->computation()->IsLoadLocal());  // Not possible.
-    LoadLocalComp* load = NULL;
-    if (current->IsBind() &&
-        current->AsBind()->computation()->IsLoadLocal()) {
-      load = current->AsBind()->computation()->AsLoadLocal();
-    }
-    StoreLocalComp* store = NULL;
-    if (current->IsDo() &&
-        current->AsDo()->computation()->IsStoreLocal()) {
-      store = current->AsDo()->computation()->AsStoreLocal();
-    } else if (current->IsBind() &&
-               current->AsBind()->computation()->IsStoreLocal()) {
-      store = current->AsBind()->computation()->AsStoreLocal();
-    }
-
-    if (load != NULL) {
-      ASSERT(current->IsBind());
-      // Update expression stack.
-      intptr_t index = load->local().BitIndexIn(var_count);
-      env->Add(CopyValue((*env)[index]));
-      // Remove instruction.
-      current = current->RemoveFromGraph();
-    } else if (store != NULL) {
-      // Update renaming environment.
-      (*env)[store->local().BitIndexIn(var_count)] = store->value();
-      if (current->IsBind()) {
-        // Update expression stack.
-        intptr_t index = store->local().BitIndexIn(var_count);
-        env->Add(CopyValue((*env)[index]));
+    BindInstr* bind = current->AsBind();
+    if (bind != NULL) {
+      LoadLocalComp* load = bind->computation()->AsLoadLocal();
+      StoreLocalComp* store = bind->computation()->AsStoreLocal();
+      if ((load != NULL) || (store != NULL)) {
+        intptr_t index;
+        if (store != NULL) {
+          index = store->local().BitIndexIn(var_count);
+          // Update renaming environment.
+          (*env)[index] = store->value();
+        } else {
+          // The graph construction ensures we do not have an unused LoadLocal
+          // computation.
+          ASSERT(bind->is_used());
+          index = load->local().BitIndexIn(var_count);
+        }
+        // Update expression stack and remove from graph.
+        if (bind->is_used()) {
+          env->Add(CopyValue((*env)[index]));
+        }
+        current = current->RemoveFromGraph();
+      } else {
+        // Not a load or store.
+        if (bind->is_used()) {
+          // Assign fresh SSA temporary and update expression stack.
+          bind->set_ssa_temp_index(current_ssa_temp_index_++);
+          env->Add(new UseVal(bind));
+        }
+        current = current->successor();
       }
-      // Remove instruction and update renaming environment.
-      current = current->RemoveFromGraph();
     } else {
-      if (current->IsBind()) {
-        // Assign new SSA temporary.
-        current->AsDefinition()->set_ssa_temp_index(current_ssa_temp_index_++);
-        // Update expression stack.
-        env->Add(new UseVal(current->AsDefinition()));
-      }
+      // Not a computation.
       current = current->successor();
     }
   }
 
   // 3. Process dominated blocks.
   for (intptr_t i = 0; i < block_entry->dominated_blocks().length(); ++i) {
     BlockEntryInstr* block = block_entry->dominated_blocks()[i];
     ZoneGrowableArray<Value*>* new_env =
         new ZoneGrowableArray<Value*>(env->length());
     new_env->AddArray(*env);
@@ skipping 30 matching lines @@
   char* chars = reinterpret_cast<char*>(
       Isolate::Current()->current_zone()->Allocate(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