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

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 2595 matching lines @@
             worklist.Add(block);
           }
         }
       }
     }
   }
 }
 
 
 void FlowGraphBuilder::Rename(intptr_t var_count) {
-  // Initialize start environment:
-  // All locals are initialized with #null.
-  // TODO(fschneider): Support parameters. All parameters are initially located
-  // on the stack.
   // TODO(fschneider): Store var_count in the FlowGraphBuilder instead of
   // passing it around.
-  ZoneGrowableArray<Value*>* start_env =
-      new ZoneGrowableArray<Value*>(var_count);
-  if (parsed_function().function().num_fixed_parameters() > 0) {
-    Bailout("Fixed parameter support in SSA");
+  // TODO(fschneider): Support catch-entry.
+  if (graph_entry_->SuccessorCount() > 1) {
+    Bailout("Catch-entry support in SSA.");
   }
+  // TODO(fschneider): Support copied parameters.
   if (parsed_function().copied_parameter_count()) {
     Bailout("Copied parameter support in SSA");
   }
+  ASSERT(var_count == (parsed_function().stack_local_count() +
+                       parsed_function().function().num_fixed_parameters()));
+
+  // Initialize start environment.
+  ZoneGrowableArray<Value*>* start_env =
+      new ZoneGrowableArray<Value*>(var_count);
+  intptr_t i = 0;
+  for (; i < parsed_function().function().num_fixed_parameters(); ++i) {
+    ParameterInstr* param = new ParameterInstr(i);
+    param->set_ssa_temp_index(current_ssa_temp_index_++);  // New SSA temp.
+    start_env->Add(new UseVal(param));
+  }
+
+  // All locals are initialized with #null.
   Value* null_value = new ConstantVal(Object::ZoneHandle());
-  // TODO(fschneider): Change this assert once parameters are supported.
-  ASSERT(var_count == parsed_function().stack_local_count());
-  for (intptr_t i = 0; i < var_count; i++) {
+  for (; i < var_count; i++) {
     start_env->Add(null_value);
   }
-  graph_entry_->set_start_env(start_env);
+  graph_entry_->set_start_env(new Environment(start_env));
 
   BlockEntryInstr* normal_entry = graph_entry_->SuccessorAt(0);
   ASSERT(normal_entry != NULL);  // Must have entry.
   ZoneGrowableArray<Value*>* env = new ZoneGrowableArray<Value*>(var_count);
   env->AddArray(*start_env);
   RenameRecursive(normal_entry, env, var_count);
 }
 
 
 static intptr_t WhichPred(BlockEntryInstr* predecessor,
@@ skipping 110 matching lines @@
         env->Add(new UseVal(current->AsDefinition()));
       }
       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*>(var_count);
+        new ZoneGrowableArray<Value*>(env->length());
     new_env->AddArray(*env);
     RenameRecursive(block, new_env, var_count);
   }
 
   // 4. Process successor block. We have edge-split form, so that only blocks
   // with one successor can have a join block as successor.
   if ((block_entry->last_instruction()->SuccessorCount() == 1) &&
       block_entry->last_instruction()->SuccessorAt(0)->IsJoinEntry()) {
     JoinEntryInstr* successor =
         block_entry->last_instruction()->SuccessorAt(0)->AsJoinEntry();
@@ skipping 21 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