Make function proxies work as constructors.

src/x64/builtins-x64.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 61 matching lines @@
   __ JumpToExternalReference(ExternalReference(id, masm->isolate()), 1);
 }
 
 
 void Builtins::Generate_JSConstructCall(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- rax: number of arguments
   //  -- rdi: constructor function
   // -----------------------------------
 
-  Label non_function_call;
+  Label slow, non_function_call;
   // Check that function is not a smi.
   __ JumpIfSmi(rdi, &non_function_call);
   // Check that function is a JSFunction.
   __ CmpObjectType(rdi, JS_FUNCTION_TYPE, rcx);
-  __ j(not_equal, &non_function_call);
+  __ j(not_equal, &slow);
 
   // Jump to the function-specific construct stub.
   __ movq(rbx, FieldOperand(rdi, JSFunction::kSharedFunctionInfoOffset));
   __ movq(rbx, FieldOperand(rbx, SharedFunctionInfo::kConstructStubOffset));
   __ lea(rbx, FieldOperand(rbx, Code::kHeaderSize));
   __ jmp(rbx);
 
   // rdi: called object
   // rax: number of arguments
+  // rcx: object map
+  Label do_call;
+  __ bind(&slow);
+  __ CmpInstanceType(rcx, JS_FUNCTION_PROXY_TYPE);
+  __ j(not_equal, &non_function_call);
+  __ GetBuiltinEntry(rdx, Builtins::CALL_FUNCTION_PROXY_AS_CONSTRUCTOR);
+  __ jmp(&do_call);
+
   __ bind(&non_function_call);
+  __ GetBuiltinEntry(rdx, Builtins::CALL_NON_FUNCTION_AS_CONSTRUCTOR);
+  __ bind(&do_call);
   // Set expected number of arguments to zero (not changing rax).
   __ Set(rbx, 0);
-  __ GetBuiltinEntry(rdx, Builtins::CALL_NON_FUNCTION_AS_CONSTRUCTOR);
   __ SetCallKind(rcx, CALL_AS_METHOD);
   __ Jump(masm->isolate()->builtins()->ArgumentsAdaptorTrampoline(),
           RelocInfo::CODE_TARGET);
 }
 
 
 static void Generate_JSConstructStubHelper(MacroAssembler* masm,
                                            bool is_api_function,
                                            bool count_constructions) {
   // Should never count constructions for api objects.
@@ skipping 1443 matching lines @@
   Deoptimizer::EntryGenerator generator(masm, Deoptimizer::OSR);
   generator.Generate();
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64