X87: [turbofan] Enable concurrent (re)compilation.

src/compiler/x87/instruction-selector-x87.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/base/adapters.h"
 #include "src/compiler/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 
 namespace v8 {
@@ skipping 46 matching lines @@
 
   bool CanBeImmediate(Node* node) {
     switch (node->opcode()) {
       case IrOpcode::kInt32Constant:
       case IrOpcode::kNumberConstant:
       case IrOpcode::kExternalConstant:
       case IrOpcode::kRelocatableInt32Constant:
       case IrOpcode::kRelocatableInt64Constant:
         return true;
       case IrOpcode::kHeapConstant: {
+// TODO(bmeurer): We must not dereference handles concurrently. If we
+// really have to this here, then we need to find a way to put this
+// information on the HeapConstant node already.
+#if 0
         // Constants in new space cannot be used as immediates in V8 because
         // the GC does not scan code objects when collecting the new generation.
         Handle<HeapObject> value = OpParameter<Handle<HeapObject>>(node);
         Isolate* isolate = value->GetIsolate();
         return !isolate->heap()->InNewSpace(*value);
+#endif
       }
       default:
         return false;
     }
   }
 
   AddressingMode GenerateMemoryOperandInputs(Node* index, int scale, Node* base,
                                              Node* displacement_node,
                                              InstructionOperand inputs[],
                                              size_t* input_count) {
@@ skipping 1531 matching lines @@
            MachineOperatorBuilder::kFloat32RoundTruncate |
            MachineOperatorBuilder::kFloat64RoundTruncate |
            MachineOperatorBuilder::kFloat32RoundTiesEven |
            MachineOperatorBuilder::kFloat64RoundTiesEven;
   return flags;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8