Put live register bits in stackmaps.

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.h"
@@ skipping 1752 matching lines @@
 
   TRACE_ALLOC(OS::Print("range [%d, %d) for v%d has been allocated to ",
                         range->Start(), range->End(), range->vreg()));
   TRACE_ALLOC(loc.Print());
   TRACE_ALLOC(OS::Print(":\n"));
 
   for (UsePosition* use = range->first_use(); use != NULL; use = use->next()) {
     ConvertUseTo(use, loc);
   }
 
+  // Add live registers at all safepoints for instructions with slow-path
+  // code.
   if (loc.IsMachineRegister()) {
     for (SafepointPosition* safepoint = range->first_safepoint();
          safepoint != NULL;
          safepoint = safepoint->next()) {
-      safepoint->locs()->live_registers()->Add(loc);
+      if (!safepoint->locs()->always_calls()) {
+        ASSERT(safepoint->locs()->can_call());
+        safepoint->locs()->live_registers()->Add(loc);
+      }
     }
   }
 }
 
 
 void FlowGraphAllocator::AdvanceActiveIntervals(const intptr_t start) {
   for (intptr_t reg = 0; reg < NumberOfRegisters(); reg++) {
     if (registers_[reg].is_empty()) continue;
 
     intptr_t first_evicted = -1;
@@ skipping 359 matching lines @@
     OS::Print("-- [after ssa allocator] ir [%s] -------------\n",
               function.ToFullyQualifiedCString());
     FlowGraphPrinter printer(flow_graph_, true);
     printer.PrintBlocks();
     OS::Print("----------------------------------------------\n");
   }
 }
 
 
 }  // namespace dart