VM: Link native calls lazily.

runtime/vm/intermediate_language_x64.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/globals.h"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/dart_entry.h"
@@ skipping 763 matching lines @@
 
   // Push the result place holder initialized to NULL.
   __ PushObject(Object::null_object());
   // Pass a pointer to the first argument in RAX.
   if (!function().HasOptionalParameters()) {
     __ leaq(RAX, Address(RBP, (kParamEndSlotFromFp +
                                function().NumParameters()) * kWordSize));
   } else {
     __ leaq(RAX, Address(RBP, kFirstLocalSlotFromFp * kWordSize));
   }
-  ExternalLabel label(reinterpret_cast<uword>(native_c_function()));
-  __ LoadExternalLabel(RBX, &label, kNotPatchable);
   __ LoadImmediate(R10, Immediate(argc_tag));
-  const StubEntry& stub_entry = (is_bootstrap_native() || is_leaf_call) ?
-      *StubCode::CallBootstrapCFunction_entry() :
-      *StubCode::CallNativeCFunction_entry();
+  const StubEntry* stub_entry;
+  if (link_lazily()) {
+    stub_entry = StubCode::CallBootstrapCFunction_entry();
+    __ LoadExternalLabel(
+        RBX, &NativeEntry::LinkNativeCallLabel(), kPatchable);
+  } else {
+    stub_entry = (is_bootstrap_native() || is_leaf_call)
+        ? StubCode::CallBootstrapCFunction_entry()
+        : StubCode::CallNativeCFunction_entry();
+    const ExternalLabel label(reinterpret_cast<uword>(native_c_function()));
+    __ LoadExternalLabel(RBX, &label, kNotPatchable);
+  }
   compiler->GenerateCall(token_pos(),
-                         stub_entry,
+                         *stub_entry,
                          RawPcDescriptors::kOther,
                          locs());
   __ popq(result);
 }
 
 
 static bool CanBeImmediateIndex(Value* index, intptr_t cid) {
   if (!index->definition()->IsConstant()) return false;
   const Object& constant = index->definition()->AsConstant()->value();
   if (!constant.IsSmi()) return false;
@@ skipping 5631 matching lines @@
   __ Drop(1);
   __ popq(result);
 }
 
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_X64