Add stack alignment check to ia32 and x64

src/ia32/codegen-ia32.cc

 // Copyright 2010 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 11722 matching lines @@
                               int /* alignment_skew */) {
   // eax: result parameter for PerformGC, if any
   // ebx: pointer to C function  (C callee-saved)
   // ebp: frame pointer  (restored after C call)
   // esp: stack pointer  (restored after C call)
   // edi: number of arguments including receiver  (C callee-saved)
   // esi: pointer to the first argument (C callee-saved)
 
   // Result returned in eax, or eax+edx if result_size_ is 2.
 
+  // Check stack alignment.
+  if (FLAG_debug_code) {
+    __ CheckStackAlignment();
+  }
+
   if (do_gc) {
+    // Pass failure code returned from last attempt as first argument to
+    // PerformGC. No need to use PrepareCallCFunction/CallCFunction here as the
+    // stack alignment is known to be correct. This function takes one argument
+    // which is passed on the stack, and we know that the stack has been
+    // prepared to pass at least one argument.
     __ mov(Operand(esp, 0 * kPointerSize), eax);  // Result.
     __ call(FUNCTION_ADDR(Runtime::PerformGC), RelocInfo::RUNTIME_ENTRY);
   }
 
   ExternalReference scope_depth =
       ExternalReference::heap_always_allocate_scope_depth();
   if (always_allocate_scope) {
     __ inc(Operand::StaticVariable(scope_depth));
   }
 
@@ skipping 1122 matching lines @@
 
   // Call the runtime; it returns -1 (less), 0 (equal), or 1 (greater)
   // tagged as a small integer.
   __ bind(&runtime);
   __ TailCallRuntime(Runtime::kStringCompare, 2, 1);
 }
 
 #undef __
 
 } }  // namespace v8::internal