ARM: replace RegExpCEntryStub with DirectCEntryStub.

src/arm/regexp-macro-assembler-arm.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 1037 matching lines @@
 void RegExpMacroAssemblerARM::WriteStackPointerToRegister(int reg) {
   __ ldr(r1, MemOperand(frame_pointer(), kStackHighEnd));
   __ sub(r0, backtrack_stackpointer(), r1);
   __ str(r0, register_location(reg));
 }
 
 
 // Private methods:
 
 void RegExpMacroAssemblerARM::CallCheckStackGuardState(Register scratch) {
-  static const int num_arguments = 3;
-  __ PrepareCallCFunction(num_arguments, scratch);
+  __ PrepareCallCFunction(3, scratch);
+
   // RegExp code frame pointer.
   __ mov(r2, frame_pointer());
   // Code* of self.
   __ mov(r1, Operand(masm_->CodeObject()));
-  // r0 becomes return address pointer.
+
+  // We need to make room for the return address on the stack.
+  int stack_alignment = OS::ActivationFrameAlignment();
+  if (stack_alignment < kPointerSize) stack_alignment = kPointerSize;

[Benedikt Meurer, 2013/09/10 11:07:06]

Nit: I think we should simply ASSERT(IsAligned(stack_alignment, kPointerSize))
here. Otherwise to be 100% correct, we would have to make sure that kPointerSize
is a multiple of stack_alignment.

[Rodolph Perfetta, 2013/09/10 13:50:00]

Done.

+  __ sub(sp, sp, Operand(stack_alignment));
+
+  // r0 will point to the return address, placed by DirectCEntry.
+  __ mov(r0, sp);
+
   ExternalReference stack_guard_check =
       ExternalReference::re_check_stack_guard_state(isolate());
-  CallCFunctionUsingStub(stack_guard_check, num_arguments);
+  __ mov(ip, Operand(stack_guard_check));
+  DirectCEntryStub stub;
+  stub.GenerateCall(masm_, ip);
+
+  // Drop the return address from the stack.
+  __ add(sp, sp, Operand(stack_alignment));
+
+  if (OS::ActivationFrameAlignment() != 0) {

[Benedikt Meurer, 2013/09/10 11:07:06]

Nit: We can also safely assert that the stack_alignment is never 0.

[Rodolph Perfetta, 2013/09/10 13:50:00]

Done.

+    __ ldr(sp, MemOperand(sp, 0));
+  }
+  __ mov(code_pointer(), Operand(masm_->CodeObject()));
 }
 
 
 // Helper function for reading a value out of a stack frame.
 template <typename T>
 static T& frame_entry(Address re_frame, int frame_offset) {
   return reinterpret_cast<T&>(Memory::int32_at(re_frame + frame_offset));
 }
 
 
@@ skipping 209 matching lines @@
   __ jmp(&new_pool_skip);
   EmitBacktrackConstantPool();
   __ bind(&new_pool_skip);
   int offset = backtrack_constant_pool_offset_;
   backtrack_constant_pool_offset_ += kPointerSize;
   backtrack_constant_pool_capacity_--;
   return offset;
 }
 
 
-void RegExpMacroAssemblerARM::CallCFunctionUsingStub(
-    ExternalReference function,
-    int num_arguments) {
-  // Must pass all arguments in registers. The stub pushes on the stack.
-  ASSERT(num_arguments <= 4);
-  __ mov(code_pointer(), Operand(function));
-  RegExpCEntryStub stub;
-  __ CallStub(&stub);
-  if (OS::ActivationFrameAlignment() != 0) {
-    __ ldr(sp, MemOperand(sp, 0));
-  }
-  __ mov(code_pointer(), Operand(masm_->CodeObject()));
-}
-
-
 bool RegExpMacroAssemblerARM::CanReadUnaligned() {
   return CpuFeatures::IsSupported(UNALIGNED_ACCESSES) && !slow_safe();
 }
 
 
 void RegExpMacroAssemblerARM::LoadCurrentCharacterUnchecked(int cp_offset,
                                                             int characters) {
   Register offset = current_input_offset();
   if (cp_offset != 0) {
     // r4 is not being used to store the capture start index at this point.
@@ skipping 22 matching lines @@
     if (characters == 2) {
       __ ldr(current_character(), MemOperand(end_of_input_address(), offset));
     } else {
       ASSERT(characters == 1);
       __ ldrh(current_character(), MemOperand(end_of_input_address(), offset));
     }
   }
 }
 
 
-void RegExpCEntryStub::Generate(MacroAssembler* masm_) {
-  int stack_alignment = OS::ActivationFrameAlignment();
-  if (stack_alignment < kPointerSize) stack_alignment = kPointerSize;
-  // Stack is already aligned for call, so decrement by alignment
-  // to make room for storing the link register.
-  __ str(lr, MemOperand(sp, stack_alignment, NegPreIndex));
-  __ mov(r0, sp);
-  __ Call(r5);
-  __ ldr(pc, MemOperand(sp, stack_alignment, PostIndex));
-}
-
 #undef __
 
 #endif  // V8_INTERPRETED_REGEXP
 
 }}  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM