Reapply "Added support for copied parameters to the SSA compiler."

runtime/vm/flow_graph_allocator.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_allocator.h"
 
 #include "vm/bit_vector.h"
 #include "vm/intermediate_language.h"
 #include "vm/il_printer.h"
 #include "vm/flow_graph_builder.h"
@@ skipping 429 matching lines @@
       // Skip parallel moves that we insert while processing instructions.
       if (!current->IsParallelMove()) {
         ProcessOneInstruction(block, current);
       }
       current = current->previous();
     }
 
     ConnectIncomingPhiMoves(block);
   }
 
+  const bool copied = builder_->parsed_function().copied_parameter_count() > 0;
+
   // Process incoming parameters.
   const intptr_t fixed_parameters_count =
       builder_->parsed_function().function().num_fixed_parameters();
 
   GraphEntryInstr* graph_entry = postorder_[block_count - 1]->AsGraphEntry();
   for (intptr_t i = 0; i < graph_entry->start_env()->values().length(); i++) {
     Value* val = graph_entry->start_env()->values()[i];
     if (val->IsUse()) {
       ParameterInstr* param = val->AsUse()->definition()->AsParameter();
 
       LiveRange* range = GetLiveRange(param->ssa_temp_index());
       range->AddUseInterval(graph_entry->start_pos(), graph_entry->end_pos());
       range->DefineAt(graph_entry->start_pos());
 
-      // Slot index for the rightmost parameter is -1.
-      const intptr_t slot_index = param->index() - fixed_parameters_count;
+      // Slot index for the leftmost copied parameter is 0.
+      intptr_t slot_index = param->index();
+      if (!copied) {
+        // Slot index for the rightmost fixed parameter is -1.
+        slot_index -= fixed_parameters_count;
+      }
+
       range->set_assigned_location(Location::StackSlot(slot_index));
       range->set_spill_slot(Location::StackSlot(slot_index));
+      if (copied) {
+        ASSERT(spill_slots_.length() == slot_index);
+        spill_slots_.Add(range->End());

[zerny-google, 2012/08/06 09:39:53]

This has to come before splitting. This is the bug fix.

+      }
 
       range->finger()->Initialize(range);
       UsePosition* use = range->finger()->FirstRegisterBeneficialUse(
           graph_entry->start_pos());
       if (use != NULL) {
         LiveRange* tail = SplitBetween(range,
                                        graph_entry->start_pos(),
                                        use->pos());
         AddToUnallocated(tail);
       }
@@ skipping 1359 matching lines @@
     OS::Print("-- [after ssa allocator] ir [%s] -------------\n",
               function.ToFullyQualifiedCString());
     FlowGraphPrinter printer(Function::Handle(), block_order_, true);
     printer.PrintBlocks();
     OS::Print("----------------------------------------------\n");
   }
 }
 
 
 }  // namespace dart