Reland - Arm64: Ensure that csp is always aligned to 16 byte values even if jssp is not.

src/builtins.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "v8.h"
 
 #include "api.h"
 #include "arguments.h"
 #include "bootstrapper.h"
 #include "builtins.h"
@@ skipping 1586 matching lines @@
   ASSERT(!initialized_);
 
   // Create a scope for the handles in the builtins.
   HandleScope scope(isolate);
 
   const BuiltinDesc* functions = builtin_function_table.functions();
 
   // For now we generate builtin adaptor code into a stack-allocated
   // buffer, before copying it into individual code objects. Be careful
   // with alignment, some platforms don't like unaligned code.
-  // TODO(jbramley): I had to increase the size of this buffer from 8KB because
-  // we can generate a lot of debug code on ARM64.
-  union { int force_alignment; byte buffer[16*KB]; } u;
+#ifdef DEBUG
+  // We can generate a lot of debug code on Arm64.
+  const size_t buffer_size = 32*KB;
+#else
+  const size_t buffer_size = 8*KB;
+#endif
+  union { int force_alignment; byte buffer[buffer_size]; } 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, 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
@@ skipping 86 matching lines @@
 }
 BUILTIN_LIST_C(DEFINE_BUILTIN_ACCESSOR_C)
 BUILTIN_LIST_A(DEFINE_BUILTIN_ACCESSOR_A)
 BUILTIN_LIST_H(DEFINE_BUILTIN_ACCESSOR_H)
 BUILTIN_LIST_DEBUG_A(DEFINE_BUILTIN_ACCESSOR_A)
 #undef DEFINE_BUILTIN_ACCESSOR_C
 #undef DEFINE_BUILTIN_ACCESSOR_A
 
 
 } }  // namespace v8::internal