Add an explicit push-argument instruction to the IL.

vm/flow_graph_compiler.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/globals.h"  // Needed here to get TARGET_ARCH_XXX.
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/dart_entry.h"
 #include "vm/debugger.h"
@@ skipping 581 matching lines @@
       ASSERT(loc.policy() == Location::kRequiresRegister);
       if (!stack_.is_empty() && !blocked_temp_registers[stack_.Last()]) {
         reg = stack_.Last();
         blocked_registers[reg] = true;
       } else {
         reg = AllocateFreeRegister(blocked_registers);
       }
       locs->set_in(i, Location::RegisterLocation(reg));
     }
 
-    Pop(reg, instr->InputAt(i));
+    if (!instr->IsPushArgument()) Pop(reg, instr->InputAt(i));

[Kevin Millikin (Google), 2012/07/26 13:03:18]

This deserves some small comment like: "Inputs are consumed immediately at their
use except for outgoing arguments, which are consumed after the call is
completed."

[Florian Schneider, 2012/07/26 13:45:24]

Done.

   }
 
   // If this instruction is call spill everything that was not consumed by
   // input locations.
   if (locs->is_call() || instr->IsBranch() || instr->IsGoto()) {
     Spill();
   }
 
   // Allocate all unallocated temp locations.
   for (intptr_t i = 0; i < locs->temp_count(); i++) {
@@ skipping 181 matching lines @@
       return;
     }
   }
 
   // This move is not blocked.
   EmitMove(index);
 }
 
 
 }  // namespace dart