MIPS: cleanup api callbacks now that handles are never returned directly

src/mips/macro-assembler-mips.cc

 // Copyright 2012 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 3945 matching lines @@
 static int AddressOffset(ExternalReference ref0, ExternalReference ref1) {
   return ref0.address() - ref1.address();
 }
 
 
 void MacroAssembler::CallApiFunctionAndReturn(ExternalReference function,
                                               Address function_address,
                                               ExternalReference thunk_ref,
                                               Register thunk_last_arg,
                                               int stack_space,
-                                              bool returns_handle,
                                               int return_value_offset_from_fp) {
   ExternalReference next_address =
       ExternalReference::handle_scope_next_address(isolate());
   const int kNextOffset = 0;
   const int kLimitOffset = AddressOffset(
       ExternalReference::handle_scope_limit_address(isolate()),
       next_address);
   const int kLevelOffset = AddressOffset(
       ExternalReference::handle_scope_level_address(isolate()),
       next_address);
 
   // Allocate HandleScope in callee-save registers.
   li(s3, Operand(next_address));
   lw(s0, MemOperand(s3, kNextOffset));
   lw(s1, MemOperand(s3, kLimitOffset));
   lw(s2, MemOperand(s3, kLevelOffset));
   Addu(s2, s2, Operand(1));
   sw(s2, MemOperand(s3, kLevelOffset));
 
   if (FLAG_log_timer_events) {
     FrameScope frame(this, StackFrame::MANUAL);
     PushSafepointRegisters();
     PrepareCallCFunction(1, a0);
     li(a0, Operand(ExternalReference::isolate_address(isolate())));
     CallCFunction(ExternalReference::log_enter_external_function(isolate()), 1);
     PopSafepointRegisters();
   }
 
-  // The O32 ABI requires us to pass a pointer in a0 where the returned struct
-  // (4 bytes) will be placed. This is also built into the Simulator.
-  // Set up the pointer to the returned value (a0). It was allocated in
-  // EnterExitFrame.
-  if (returns_handle) {
-    addiu(a0, fp, ExitFrameConstants::kStackSpaceOffset);
-  }
-
   Label profiler_disabled;
   Label end_profiler_check;
   bool* is_profiling_flag =
       isolate()->cpu_profiler()->is_profiling_address();
   STATIC_ASSERT(sizeof(*is_profiling_flag) == 1);
   li(t9, reinterpret_cast<int32_t>(is_profiling_flag));
   lb(t9, MemOperand(t9, 0));
   beq(t9, zero_reg, &profiler_disabled);
 
   // Third parameter is the address of the actual getter function.
@@ skipping 19 matching lines @@
     li(a0, Operand(ExternalReference::isolate_address(isolate())));
     CallCFunction(ExternalReference::log_leave_external_function(isolate()), 1);
     PopSafepointRegisters();
   }
 
   Label promote_scheduled_exception;
   Label delete_allocated_handles;
   Label leave_exit_frame;
   Label return_value_loaded;
 
-  if (returns_handle) {
-    Label load_return_value;
-
-    // As mentioned above, on MIPS a pointer is returned - we need to
-    // dereference it to get the actual return value (which is also a pointer).
-    lw(v0, MemOperand(v0));
-
-    Branch(&load_return_value, eq, v0, Operand(zero_reg));
-    // Dereference returned value.
-    lw(v0, MemOperand(v0));
-    Branch(&return_value_loaded);
-    bind(&load_return_value);
-  }
   // Load value from ReturnValue.
   lw(v0, MemOperand(fp, return_value_offset_from_fp*kPointerSize));
   bind(&return_value_loaded);
 
   // No more valid handles (the result handle was the last one). Restore
   // previous handle scope.
   sw(s0, MemOperand(s3, kNextOffset));
   if (emit_debug_code()) {
     lw(a1, MemOperand(s3, kLevelOffset));
     Check(eq, kUnexpectedLevelAfterReturnFromApiCall, a1, Operand(s2));
@@ skipping 1541 matching lines @@
        opcode == BGTZL);
   opcode = (cond == eq) ? BEQ : BNE;
   instr = (instr & ~kOpcodeMask) | opcode;
   masm_.emit(instr);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_MIPS