[builtins] Remove some (now) unused code from C++ builtin adaptor.

src/x87/builtins-x87.cc

Index: src/x87/builtins-x87.cc
diff --git a/src/x87/builtins-x87.cc b/src/x87/builtins-x87.cc
index 47581870101035a1dfc8e6736e5edcae3dcd53d4..185a9a62dd84253775f039ab28baed7ae4ff5e87 100644
--- a/src/x87/builtins-x87.cc
+++ b/src/x87/builtins-x87.cc
@@ -22,8 +22,6 @@ void Builtins::Generate_Adaptor(MacroAssembler* masm,
                                 BuiltinExtraArguments extra_args) {
   // ----------- S t a t e -------------
   //  -- eax                : number of arguments excluding receiver
-  //                          (only guaranteed when the called function
-  //                           is not marked as DontAdaptArguments)
   //  -- edi                : called function
   //  -- esp[0]             : return address
   //  -- esp[4]             : last argument
@@ -33,13 +31,6 @@ void Builtins::Generate_Adaptor(MacroAssembler* masm,
   // -----------------------------------
   __ AssertFunction(edi);
 
-  // Make sure we operate in the context of the called function (for example
-  // ConstructStubs implemented in C++ will be run in the context of the caller
-  // instead of the callee, due to the way that [[Construct]] is defined for
-  // ordinary functions).
-  // TODO(bmeurer): Can we make this more robust?
-  __ mov(esi, FieldOperand(edi, JSFunction::kContextOffset));
-
   // Insert extra arguments.
   int num_extra_args = 0;
   if (extra_args == NEEDS_CALLED_FUNCTION) {
@@ -53,21 +44,8 @@ void Builtins::Generate_Adaptor(MacroAssembler* masm,
   }
 
   // JumpToExternalReference expects eax to contain the number of arguments
-  // including the receiver and the extra arguments.  But eax is only valid
-  // if the called function is marked as DontAdaptArguments, otherwise we
-  // need to load the argument count from the SharedFunctionInfo.
-  Label argc, done_argc;
-  __ mov(edx, FieldOperand(edi, JSFunction::kSharedFunctionInfoOffset));
-  __ mov(ebx,
-         FieldOperand(edx, SharedFunctionInfo::kFormalParameterCountOffset));
-  __ SmiUntag(ebx);
-  __ cmp(ebx, SharedFunctionInfo::kDontAdaptArgumentsSentinel);
-  __ j(equal, &argc, Label::kNear);
-  __ lea(eax, Operand(ebx, num_extra_args + 1));
-  __ jmp(&done_argc, Label::kNear);
-  __ bind(&argc);
+  // including the receiver and the extra arguments.
   __ add(eax, Immediate(num_extra_args + 1));
-  __ bind(&done_argc);
 
   __ JumpToExternalReference(ExternalReference(id, masm->isolate()));
 }