X87: fix performance regression on intel call api stubs

src/x87/code-stubs-x87.cc

 // Copyright 2012 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/v8.h"
 
 #if V8_TARGET_ARCH_X87
 
 #include "src/base/bits.h"
 #include "src/bootstrapper.h"
@@ skipping 4525 matching lines @@
   __ mov(eax, edi);
   __ jmp(&leave_exit_frame);
 }
 
 
 static void CallApiFunctionStubHelper(MacroAssembler* masm,
                                       const ParameterCount& argc,
                                       bool return_first_arg,
                                       bool call_data_undefined) {
   // ----------- S t a t e -------------
-  //  -- eax                 : callee
+  //  -- edi                 : callee
   //  -- ebx                 : call_data
   //  -- ecx                 : holder
   //  -- edx                 : api_function_address
   //  -- esi                 : context
-  //  -- edi                 : number of arguments if argc is a register
+  //  -- eax                 : number of arguments if argc is a register
   //  --
   //  -- esp[0]              : return address
   //  -- esp[4]              : last argument
   //  -- ...
   //  -- esp[argc * 4]       : first argument
   //  -- esp[(argc + 1) * 4] : receiver
   // -----------------------------------
 
-  Register callee = eax;
+  Register callee = edi;
   Register call_data = ebx;
   Register holder = ecx;
   Register api_function_address = edx;
   Register context = esi;
+  Register return_address = eax;
 
   typedef FunctionCallbackArguments FCA;
 
   STATIC_ASSERT(FCA::kContextSaveIndex == 6);
   STATIC_ASSERT(FCA::kCalleeIndex == 5);
   STATIC_ASSERT(FCA::kDataIndex == 4);
   STATIC_ASSERT(FCA::kReturnValueOffset == 3);
   STATIC_ASSERT(FCA::kReturnValueDefaultValueIndex == 2);
   STATIC_ASSERT(FCA::kIsolateIndex == 1);
   STATIC_ASSERT(FCA::kHolderIndex == 0);
   STATIC_ASSERT(FCA::kArgsLength == 7);
 
-  DCHECK(argc.is_immediate() || edi.is(argc.reg()));
+  DCHECK(argc.is_immediate() || eax.is(argc.reg()));
 
-  // pop return address and save context
-  __ xchg(context, Operand(esp, 0));
+  if (argc.is_immediate()) {
+    __ pop(return_address);
+    // context save.
+    __ push(context);
+  } else {
+    // pop return address and save context
+    __ xchg(context, Operand(esp, 0));
+    return_address = context;
+  }
 
   // callee
   __ push(callee);
 
   // call data
   __ push(call_data);
 
   Register scratch = call_data;
   if (!call_data_undefined) {
     // return value
     __ push(Immediate(masm->isolate()->factory()->undefined_value()));
     // return value default
     __ push(Immediate(masm->isolate()->factory()->undefined_value()));
   } else {
     // return value
     __ push(scratch);
     // return value default
     __ push(scratch);
   }
   // isolate
   __ push(Immediate(reinterpret_cast<int>(masm->isolate())));
   // holder
   __ push(holder);
 
   __ mov(scratch, esp);
 
   // push return address
-  __ push(context);
+  __ push(return_address);
 
   // load context from callee
   __ mov(context, FieldOperand(callee, JSFunction::kContextOffset));
 
   // API function gets reference to the v8::Arguments. If CPU profiler
   // is enabled wrapper function will be called and we need to pass
   // address of the callback as additional parameter, always allocate
   // space for it.
   const int kApiArgc = 1 + 1;
 
@@ skipping 52 matching lines @@
     stack_space_operand = nullptr;
   }
   CallApiFunctionAndReturn(masm, api_function_address, thunk_ref,
                            ApiParameterOperand(1), stack_space,
                            stack_space_operand, return_value_operand,
                            &context_restore_operand);
 }
 
 
 void CallApiFunctionStub::Generate(MacroAssembler* masm) {
-  // TODO(dcarney): make eax contain the function address.
   bool call_data_undefined = this->call_data_undefined();
-  CallApiFunctionStubHelper(masm, ParameterCount(edi), false,
+  CallApiFunctionStubHelper(masm, ParameterCount(eax), false,
                             call_data_undefined);
 }
 
 
 void CallApiAccessorStub::Generate(MacroAssembler* masm) {
   bool is_store = this->is_store();
   int argc = this->argc();
   bool call_data_undefined = this->call_data_undefined();
   CallApiFunctionStubHelper(masm, ParameterCount(argc), is_store,
                             call_data_undefined);
@@ skipping 35 matching lines @@
                            ApiParameterOperand(2), kStackSpace, nullptr,
                            Operand(ebp, 7 * kPointerSize), NULL);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X87