Don't call FastNewFunctionContextStub if context is bigger than kMaxRegularHeapObjectSize.

src/crankshaft/x64/lithium-codegen-x64.cc

 // Copyright 2013 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.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/crankshaft/x64/lithium-codegen-x64.h"
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 161 matching lines @@
     bool need_write_barrier = true;
     // Argument to NewContext is the function, which is still in rdi.
     int slots = info_->scope()->num_heap_slots() - Context::MIN_CONTEXT_SLOTS;
     Safepoint::DeoptMode deopt_mode = Safepoint::kNoLazyDeopt;
     if (info()->scope()->is_script_scope()) {
       __ Push(rdi);
       __ Push(info()->scope()->scope_info());
       __ CallRuntime(Runtime::kNewScriptContext);
       deopt_mode = Safepoint::kLazyDeopt;
     } else {
-      FastNewFunctionContextStub stub(isolate());
-      __ Set(FastNewFunctionContextDescriptor::SlotsRegister(), slots);
-      __ CallStub(&stub);
-      // Result of FastNewFunctionContextStub is always in new space.
-      need_write_barrier = false;
+      if (slots <= FastNewFunctionContextStub::kMaximumSlots) {
+        FastNewFunctionContextStub stub(isolate());
+        __ Set(FastNewFunctionContextDescriptor::SlotsRegister(), slots);
+        __ CallStub(&stub);
+        // Result of FastNewFunctionContextStub is always in new space.
+        need_write_barrier = false;
+      } else {
+        __ Push(rdi);
+        __ CallRuntime(Runtime::kNewFunctionContext);
+      }
     }
     RecordSafepoint(deopt_mode);
 
     // Context is returned in rax.  It replaces the context passed to us.
     // It's saved in the stack and kept live in rsi.
     __ movp(rsi, rax);
     __ movp(Operand(rbp, StandardFrameConstants::kContextOffset), rax);
 
     // Copy any necessary parameters into the context.
     int num_parameters = info()->scope()->num_parameters();
@@ skipping 5247 matching lines @@
   __ bind(deferred->exit());
   __ bind(&done);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64