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

src/mips/builtins-mips.cc

Index: src/mips/builtins-mips.cc
diff --git a/src/mips/builtins-mips.cc b/src/mips/builtins-mips.cc
index 573e48a984df54bbbf1076a069fc63cdaa30e0b1..5f3d3e20129744aff217835b5c0f5ec259b930e2 100644
--- a/src/mips/builtins-mips.cc
+++ b/src/mips/builtins-mips.cc
@@ -23,8 +23,6 @@ void Builtins::Generate_Adaptor(MacroAssembler* masm,
                                 BuiltinExtraArguments extra_args) {
   // ----------- S t a t e -------------
   //  -- a0                 : number of arguments excluding receiver
-  //                          (only guaranteed when the called function
-  //                           is not marked as DontAdaptArguments)
   //  -- a1                 : called function
   //  -- sp[0]              : last argument
   //  -- ...
@@ -33,13 +31,6 @@ void Builtins::Generate_Adaptor(MacroAssembler* masm,
   // -----------------------------------
   __ AssertFunction(a1);
 
-  // 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?
-  __ lw(cp, FieldMemOperand(a1, JSFunction::kContextOffset));
-
   // Insert extra arguments.
   int num_extra_args = 0;
   if (extra_args == NEEDS_CALLED_FUNCTION) {
@@ -50,21 +41,8 @@ void Builtins::Generate_Adaptor(MacroAssembler* masm,
   }
 
   // JumpToExternalReference expects a0 to contain the number of arguments
-  // including the receiver and the extra arguments.  But a0 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;
-  __ lw(a2, FieldMemOperand(a1, JSFunction::kSharedFunctionInfoOffset));
-  __ lw(a2,
-        FieldMemOperand(a2, SharedFunctionInfo::kFormalParameterCountOffset));
-  __ SmiUntag(a2);
-  __ Branch(&argc, eq, a2,
-            Operand(SharedFunctionInfo::kDontAdaptArgumentsSentinel));
-  __ Addu(a0, a2, num_extra_args + 1);
-  __ jmp(&done_argc);
-  __ bind(&argc);
+  // including the receiver and the extra arguments.
   __ Addu(a0, a0, num_extra_args + 1);
-  __ bind(&done_argc);
 
   __ JumpToExternalReference(ExternalReference(id, masm->isolate()));
 }