Add support for fixed parameters in SSA builder and fix a bug in the pre-order graph traversal.

vm/intermediate_language.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/intermediate_language.h"
 
 #include "vm/bit_vector.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph_builder.h"
 #include "vm/flow_graph_compiler.h"
@@ skipping 268 matching lines @@
 Value* PhiInstr::InputAt(intptr_t i) const {
   return inputs_[i];
 }
 
 
 void PhiInstr::SetInputAt(intptr_t i, Value* value) {
   inputs_[i] = value;
 }
 
 
+intptr_t ParameterInstr::InputCount() const {
+  return 0;
+}
+
+
+Value* ParameterInstr::InputAt(intptr_t i) const {
+  UNREACHABLE();
+  return NULL;
+}
+
+
+void ParameterInstr::SetInputAt(intptr_t i, Value* value) {
+  UNREACHABLE();
+}
+
+
 intptr_t DoInstr::InputCount() const {
   return computation()->InputCount();
 }
 
 
 Value* DoInstr::InputAt(intptr_t i) const {
   return computation()->InputAt(i);
 }
 
 
@@ skipping 135 matching lines @@
 
   // 1. Record control-flow-graph basic-block predecessors.
   AddPredecessor(current_block);
 
   // 2. If the block has already been reached by the traversal, we are
   // done.  Blocks with a single predecessor cannot have been reached
   // before.
   ASSERT(!IsTargetEntry() || (preorder_number() == -1));
   if (preorder_number() >= 0) return;
 
-  // 3. The last entry in the preorder array is the spanning-tree parent.
-  intptr_t parent_number = preorder->length() - 1;
-  parent->Add(parent_number);
+  // 3. The current block is the spanning-tree parent.
+  parent->Add(current_block->preorder_number());
 
   // 4. Assign preorder number and add the block entry to the list.
   // Allocate an empty set of assigned variables for the block.
-  set_preorder_number(parent_number + 1);
+  set_preorder_number(preorder->length());
   preorder->Add(this);
   BitVector* vars =
       (variable_count == 0) ? NULL : new BitVector(variable_count);
   assigned_vars->Add(vars);
   // The preorder, parent, and assigned_vars arrays are all indexed by
   // preorder block number, so they should stay in lockstep.
   ASSERT(preorder->length() == parent->length());
   ASSERT(preorder->length() == assigned_vars->length());
 
   // 5. Iterate straight-line successors until a branch instruction or
@@ skipping 876 matching lines @@
   const ExternalLabel label(closure_function.ToCString(), stub.EntryPoint());
   compiler->GenerateCall(token_pos(), try_index(), &label,
                          PcDescriptors::kOther);
   __ Drop(2);  // Discard type arguments and receiver.
 }
 
 
 #undef __
 
 }  // namespace dart