Allow platforms (linux and win32) to not force 16-byte alignment...

src/codegen-ia32.cc

 // Copyright 2006-2008 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 5191 matching lines @@
 
 #undef __
 #define __  masm->
 
 
 void CEntryStub::GenerateReserveCParameterSpace(MacroAssembler* masm,
                                                 int num_parameters) {
   if (num_parameters > 0) {
     __ sub(Operand(esp), Immediate(num_parameters * kPointerSize));
   }
-  // OS X activation frames are 16 byte-aligned
-  // (see "Mac OS X ABI Function Call Guide").
-  const int kFrameAlignment = 16;
-  ASSERT(IsPowerOf2(kFrameAlignment));
-  __ and_(esp, -kFrameAlignment);
+  static const int kFrameAlignment = OS::ActivationFrameAlignment();
+  if (kFrameAlignment > 0) {
+    ASSERT(IsPowerOf2(kFrameAlignment));
+    __ and_(esp, -kFrameAlignment);
+  }
 }
 
 
 void CEntryStub::GenerateThrowTOS(MacroAssembler* masm) {
   ASSERT(StackHandlerConstants::kSize == 6 * kPointerSize);  // adjust this code
   ExternalReference handler_address(Top::k_handler_address);
   __ mov(edx, Operand::StaticVariable(handler_address));
   __ mov(ecx, Operand(edx, -1 * kPointerSize));  // get next in chain
   __ mov(Operand::StaticVariable(handler_address), ecx);
   __ mov(esp, Operand(edx));
@@ skipping 318 matching lines @@
                                      bool is_eval) {
   Handle<Code> code = Ia32CodeGenerator::MakeCode(fun, script, is_eval);
   if (!code.is_null()) {
     Counters::total_compiled_code_size.Increment(code->instruction_size());
   }
   return code;
 }
 
 
 } }  // namespace v8::internal