Add support for fixed parameters in the register allocator.

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 2268 matching lines @@
   const Function& function = parsed_function().function();
   TargetEntryInstr* normal_entry = new TargetEntryInstr();
   graph_entry_ = new GraphEntryInstr(normal_entry);
   EffectGraphVisitor for_effect(this, 0);
   parsed_function().node_sequence()->Visit(&for_effect);
   AppendFragment(normal_entry, for_effect);
   // Check that the graph is properly terminated.
   ASSERT(!for_effect.is_open());
   GrowableArray<intptr_t> parent;
   GrowableArray<BitVector*> assigned_vars;
-  intptr_t variable_count = parsed_function_.function().num_fixed_parameters() +
+
+  const intptr_t fixed_parameter_count =
+      parsed_function_.function().num_fixed_parameters();
+  const intptr_t variable_count = fixed_parameter_count +
       parsed_function_.copied_parameter_count() +
       parsed_function_.stack_local_count();
   // Perform a depth-first traversal of the graph to build preorder and
   // postorder block orders.
   graph_entry_->DiscoverBlocks(NULL,  // Entry block predecessor.
                                &preorder_block_entries_,
                                &postorder_block_entries_,
                                &parent,
                                &assigned_vars,
-                               variable_count);
+                               variable_count,
+                               fixed_parameter_count);
   // Number blocks in reverse postorder.
   intptr_t block_count = postorder_block_entries_.length();
   for (intptr_t i = 0; i < block_count; ++i) {
     postorder_block_entries_[i]->set_block_id(block_count - i - 1);
   }
 
   if (for_optimized) {
     // Link instructions backwards for optimized compilation.
     for (intptr_t i = 0; i < block_count; ++i) {
       BlockEntryInstr* entry = postorder_block_entries_[i];
@@ skipping 225 matching lines @@
   // TODO(fschneider): Support copied parameters.
   if (parsed_function().copied_parameter_count() != 0) {
     Bailout("Copied parameter support in SSA");
   }
   ASSERT(var_count == (parsed_function().stack_local_count() +
                        parsed_function().function().num_fixed_parameters()));
 
   // Initialize start environment.
   GrowableArray<Value*> start_env(var_count);
   intptr_t i = 0;
-  for (; i < parsed_function().function().num_fixed_parameters(); ++i) {
+  const intptr_t fixed_parameter_count =
+      parsed_function().function().num_fixed_parameters();
+  for (; i < fixed_parameter_count; ++i) {
     ParameterInstr* param = new ParameterInstr(i);
     param->set_ssa_temp_index(alloc_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());
   for (; i < var_count; i++) {
     start_env.Add(null_value);
   }
-  graph_entry_->set_start_env(new Environment(start_env));
+  graph_entry_->set_start_env(
+      new Environment(start_env, fixed_parameter_count));
 
   BlockEntryInstr* normal_entry = graph_entry_->SuccessorAt(0);
   ASSERT(normal_entry != NULL);  // Must have entry.
   GrowableArray<Value*> env(var_count);
   env.AddArray(start_env);
-  RenameRecursive(normal_entry, &env, var_count);
+  RenameRecursive(normal_entry, &env, var_count, fixed_parameter_count);
 }
 
 
 // Helper to a copy a value iff it is a UseVal.
 static Value* CopyValue(Value* value) {
   return value->IsUse()
       ? new UseVal(value->AsUse()->definition())
       : value;
 }
 
 
 void FlowGraphBuilder::RenameRecursive(BlockEntryInstr* block_entry,
                                        GrowableArray<Value*>* env,
-                                       intptr_t var_count) {
+                                       intptr_t var_count,
+                                       intptr_t fixed_parameter_count) {
   // 1. Process phis first.
   if (block_entry->IsJoinEntry()) {
     JoinEntryInstr* join = block_entry->AsJoinEntry();
     if (join->phis() != NULL) {
       for (intptr_t i = 0; i < join->phis()->length(); ++i) {
         PhiInstr* phi = (*join->phis())[i];
         if (phi != NULL) {
           (*env)[i] = new UseVal(phi);
           phi->set_ssa_temp_index(alloc_ssa_temp_index());  // New SSA temp.
         }
       }
     }
   }
 
   // 2. Process normal instructions.
   for (ForwardInstructionIterator it(block_entry); !it.Done(); it.Advance()) {
     Instruction* current = it.Current();
     // Attach current environment to the instruction.
     // TODO(fschneider): Currently each instruction gets a full copy of the
     // environment. This should be optimized: Only instructions that can
     // deoptimize should have uses of the environment values.
-    current->set_env(new Environment(*env));
+    current->set_env(new Environment(*env, fixed_parameter_count));
 
     // 2a. Handle uses:
     // Update expression stack environment for each use.
     // For each use of a LoadLocal or StoreLocal: Replace it with the value
     // from the environment.
     for (intptr_t i = 0; i < current->InputCount(); ++i) {
       Value* v = current->InputAt(i);
       if (!v->IsUse()) continue;
       // Update expression stack.
       ASSERT(env->length() > var_count);
       env->RemoveLast();
       BindInstr* as_bind = v->AsUse()->definition()->AsBind();
       if ((as_bind != NULL) && as_bind->computation()->IsLoadLocal()) {
         Computation* comp = as_bind->computation();
-        intptr_t index = comp->AsLoadLocal()->local().BitIndexIn(var_count);
+        intptr_t index =
+            comp->AsLoadLocal()->local().BitIndexIn(fixed_parameter_count);
         current->SetInputAt(i, CopyValue((*env)[index]));
       }
       if ((as_bind != NULL) && as_bind->computation()->IsStoreLocal()) {
         // For each use of a StoreLocal: Replace it with the value from the
         // environment.
         Computation* comp = as_bind->computation();
-        intptr_t index = comp->AsStoreLocal()->local().BitIndexIn(var_count);
+        intptr_t index =
+            comp->AsStoreLocal()->local().BitIndexIn(fixed_parameter_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.
     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);
+          index = store->local().BitIndexIn(fixed_parameter_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);
+          index = load->local().BitIndexIn(fixed_parameter_count);
         }
         // Update expression stack and remove from graph.
         if (bind->is_used()) {
           env->Add(CopyValue((*env)[index]));
         }
         it.RemoveCurrentFromGraph();
       } else {
         // Not a load or store.
         if (bind->is_used()) {
           // Assign fresh SSA temporary and update expression stack.
           bind->set_ssa_temp_index(alloc_ssa_temp_index());
           env->Add(new UseVal(bind));
         }
       }
     }
   }
 
   // 3. Process dominated blocks.
   for (intptr_t i = 0; i < block_entry->dominated_blocks().length(); ++i) {
     BlockEntryInstr* block = block_entry->dominated_blocks()[i];
     GrowableArray<Value*> new_env(env->length());
     new_env.AddArray(*env);
-    RenameRecursive(block, &new_env, var_count);
+    RenameRecursive(block, &new_env, var_count, fixed_parameter_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();
     intptr_t pred_index = successor->IndexOfPredecessor(block_entry);
     ASSERT(pred_index >= 0);
@@ skipping 20 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