Make CTX allocatable by the register allocator.

runtime/vm/flow_graph_inliner.cc

 // Copyright (c) 2013, 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_inliner.h"
 
 #include "vm/block_scheduler.h"
 #include "vm/compiler.h"
 #include "vm/flags.h"
 #include "vm/flow_graph.h"
@@ skipping 908 matching lines @@
     // Replace remaining constants with uses by constants in the caller's
     // initial definitions.
     GrowableArray<Definition*>* defns =
         callee_graph->graph_entry()->initial_definitions();
     for (intptr_t i = 0; i < defns->length(); ++i) {
       ConstantInstr* constant = (*defns)[i]->AsConstant();
       if ((constant != NULL) && constant->HasUses()) {
         constant->ReplaceUsesWith(
             caller_graph_->GetConstant(constant->value()));
       }
+      CurrentContextInstr* context = (*defns)[i]->AsCurrentContext();
+      if ((context != NULL) && context->HasUses()) {
+        if (call->IsClosureCall()) {
+          context->ReplaceUsesWith(
+              call->AsClosureCall()->context()->definition());
+        } else {
+          context->ReplaceUsesWith(caller_graph_->CurrentContext(call->env()));

[Vyacheslav Egorov (Google), 2014/10/28 13:44:58]

Just use the empty one here. If it's not a closure call it does not need no
context.

Potentially this is even dead code because in the flow graph construction for
non-closures we already put empty context into this slot and not
CurrentContextInstr.

[Florian Schneider, 2014/10/28 19:04:31]

Done.

+        }
+      }
     }
 
     // Check that inlining maintains use lists.
     DEBUG_ASSERT(!FLAG_verify_compiler || caller_graph_->VerifyUseLists());
   }
 
   static intptr_t CountConstants(const GrowableArray<Value*>& arguments) {
     intptr_t count = 0;
     for (intptr_t i = 0; i < arguments.length(); i++) {
       if (arguments[i]->BindsToConstant()) count++;
@@ skipping 389 matching lines @@
     }
   }
   GrowableArray<Definition*>* defns =
       callee_graph->graph_entry()->initial_definitions();
   for (intptr_t i = 0; i < defns->length(); ++i) {
     ConstantInstr* constant = (*defns)[i]->AsConstant();
     if ((constant != NULL) && constant->HasUses()) {
       constant->ReplaceUsesWith(
           owner_->caller_graph()->GetConstant(constant->value()));
     }
+    CurrentContextInstr* context = (*defns)[i]->AsCurrentContext();
+    if ((context != NULL) && context->HasUses()) {
+      if (call_data.call->IsClosureCall()) {
+        context->ReplaceUsesWith(
+            call_data.call->AsClosureCall()->context()->definition());
+      } else {
+        context->ReplaceUsesWith(
+            owner_->caller_graph()->CurrentContext(call_data.call->env()));

[Vyacheslav Egorov (Google), 2014/10/28 13:44:58]

Ditto.

[Florian Schneider, 2014/10/28 19:04:31]

Done.

+      }
+    }
   }
   return true;
 }
 
 
 static Instruction* AppendInstruction(Instruction* first,
                                       Instruction* second) {
   for (intptr_t i = second->InputCount() - 1; i >= 0; --i) {
     Value* input = second->InputAt(i);
     input->definition()->AddInputUse(input);
@@ skipping 355 matching lines @@
         OS::Print("After Inlining of %s\n", flow_graph_->
                   parsed_function().function().ToFullyQualifiedCString());
         FlowGraphPrinter printer(*flow_graph_);
         printer.PrintBlocks();
       }
     }
   }
 }
 
 }  // namespace dart