Initial patch for a64.

src/builtins.cc

Index: src/builtins.cc
diff --git a/src/builtins.cc b/src/builtins.cc
index d97a4778afba13fa8307a7e5c6baa74195765824..e7198a135a57f1e7386a0f10416d8d09a29b7359 100644
--- a/src/builtins.cc
+++ b/src/builtins.cc
@@ -1734,7 +1734,9 @@ void Builtins::SetUp(bool create_heap_objects) {
   // 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.
-  union { int force_alignment; byte buffer[8*KB]; } u;
+  // TODO(jbramley): I had to increase the size of this buffer from 8KB because
+  // we can generate a lot of debug code on A64.
+  union { int force_alignment; byte buffer[16*KB]; } u;
 
   // Traverse the list of builtins and generate an adaptor in a
   // separate code object for each one.