Introduce a lazy-compile stub for functions.

runtime/vm/flow_graph_compiler_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/flow_graph_compiler.h"
 
 #include "vm/ast_printer.h"
@@ skipping 1346 matching lines @@
   __ j(ZERO, &call_target_function, Assembler::kNearJump);
   __ cmpq(RDX, RAX);
   __ j(NOT_EQUAL, &update, Assembler::kNearJump);
 
   __ Bind(&call_target_function);
   // Call the target found in the cache.  For a class id match, this is a
   // proper target for the given name and arguments descriptor.  If the
   // illegal class id was found, the target is a cache miss handler that can
   // be invoked as a normal Dart function.
   __ movq(RAX, FieldAddress(RDI, RCX, TIMES_8, base + kWordSize));
-  __ movq(RBX, FieldAddress(RAX, Function::code_offset()));
-  if (FLAG_collect_code) {
-    // If we are collecting code, the code object may be null.
-    Label is_compiled;
-    const Immediate& raw_null =
-        Immediate(reinterpret_cast<intptr_t>(Object::null()));
-    __ cmpq(RBX, raw_null);
-    __ j(NOT_EQUAL, &is_compiled, Assembler::kNearJump);
-    __ call(&StubCode::CompileFunctionRuntimeCallLabel());
-    AddCurrentDescriptor(PcDescriptors::kRuntimeCall,
-                         Isolate::kNoDeoptId,
-                         token_pos);
-    RecordSafepoint(locs);
-    __ movq(RBX, FieldAddress(RAX, Function::code_offset()));
-    __ Bind(&is_compiled);
-  }
-  __ movq(RAX, FieldAddress(RBX, Code::instructions_offset()));
+  __ movq(RCX, FieldAddress(RAX, Function::code_offset()));
+  __ movq(RCX, FieldAddress(RCX, Code::instructions_offset()));
   __ LoadObject(RBX, ic_data, PP);
   __ LoadObject(R10, arguments_descriptor, PP);
   __ AddImmediate(
-      RAX, Immediate(Instructions::HeaderSize() - kHeapObjectTag), PP);
-  __ call(RAX);
+      RCX, Immediate(Instructions::HeaderSize() - kHeapObjectTag), PP);
+  __ call(RCX);
   AddCurrentDescriptor(PcDescriptors::kOther, Isolate::kNoDeoptId, token_pos);
   RecordSafepoint(locs);
   AddDeoptIndexAtCall(Isolate::ToDeoptAfter(deopt_id), token_pos);
   __ Drop(argument_count);
 }
 
 
 void FlowGraphCompiler::EmitOptimizedStaticCall(
     const Function& function,
     const Array& arguments_descriptor,
@@ skipping 439 matching lines @@
   __ movups(reg, Address(RSP, 0));
   __ AddImmediate(RSP, Immediate(kFpuRegisterSize), PP);
 }
 
 
 #undef __
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64