Fixed alignment problem when generating code for builtins.

src/builtins.cc

 // Copyright 2011 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 1598 matching lines @@
   ASSERT(!initialized_);
   Isolate* isolate = Isolate::Current();
   Heap* heap = isolate->heap();
 
   // Create a scope for the handles in the builtins.
   HandleScope scope(isolate);
 
   const BuiltinDesc* functions = BuiltinFunctionTable::functions();
 
   // For now we generate builtin adaptor code into a stack-allocated
-  // buffer, before copying it into individual code objects.
-  byte buffer[4*KB];
+  // buffer, before copying it into individual code objects. Be careful
+  // with alignment, some platforms don't like unaligned code.
+  union { int force_alignment; byte buffer[4*KB]; } u;
 
   // Traverse the list of builtins and generate an adaptor in a
   // separate code object for each one.
   for (int i = 0; i < builtin_count; i++) {
     if (create_heap_objects) {
-      MacroAssembler masm(isolate, buffer, sizeof buffer);
+      MacroAssembler masm(isolate, u.buffer, sizeof u.buffer);
       // Generate the code/adaptor.
       typedef void (*Generator)(MacroAssembler*, int, BuiltinExtraArguments);
       Generator g = FUNCTION_CAST<Generator>(functions[i].generator);
       // We pass all arguments to the generator, but it may not use all of
       // them.  This works because the first arguments are on top of the
       // stack.
       ASSERT(!masm.has_frame());
       g(&masm, functions[i].name, functions[i].extra_args);
       // Move the code into the object heap.
       CodeDesc desc;
@@ skipping 76 matching lines @@
   return Handle<Code>(code_address);                        \
 }
 BUILTIN_LIST_C(DEFINE_BUILTIN_ACCESSOR_C)
 BUILTIN_LIST_A(DEFINE_BUILTIN_ACCESSOR_A)
 BUILTIN_LIST_DEBUG_A(DEFINE_BUILTIN_ACCESSOR_A)
 #undef DEFINE_BUILTIN_ACCESSOR_C
 #undef DEFINE_BUILTIN_ACCESSOR_A
 
 
 } }  // namespace v8::internal