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

runtime/vm/flow_graph_allocator.cc

Index: runtime/vm/flow_graph_allocator.cc
diff --git a/runtime/vm/flow_graph_allocator.cc b/runtime/vm/flow_graph_allocator.cc
index daa61fddf6561d735ad361bc7636c53927aa12a7..9a5c12f4fee7a72f517fb39ec6ec8144c1152434 100644
--- a/runtime/vm/flow_graph_allocator.cc
+++ b/runtime/vm/flow_graph_allocator.cc
@@ -447,6 +447,8 @@ void FlowGraphAllocator::BuildLiveRanges() {
     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();
@@ -461,10 +463,19 @@ void FlowGraphAllocator::BuildLiveRanges() {
       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(