PNaCl: Strip `nonnull` attributes from pointer arguments.

lib/Transforms/NaCl/ReplacePtrsWithInts.cpp

 //===- ReplacePtrsWithInts.cpp - Convert pointer values to integer values--===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This pass strips out aggregate pointer types and replaces them with
@@ skipping 313 matching lines @@
           report_fatal_error("ReplacePtrsWithInts cannot handle "
                              "byval, sret or nest attrs");
           break;
         // Strip these attributes because they apply only to pointers. This pass
         // rewrites pointer arguments, thus these parameter attributes are
         // meaningless. Also, they are rejected by the PNaCl module verifier.
         case Attribute::NoCapture:
         case Attribute::NoAlias:
         case Attribute::ReadNone:
         case Attribute::ReadOnly:
+        case Attribute::NonNull:
           break;
         default:
           AB.addAttribute(*Attr);
       }
     }
     AttrList.push_back(AttributeSet::get(Context, Index, AB));
   }
   return AttributeSet::get(Context, AttrList);
 }
 
@@ skipping 274 matching lines @@
     // Delete the now-unused bitcast ConstantExprs that we created so
     // that they don't interfere with StripDeadPrototypes.
     Func->removeDeadConstantUsers();
   }
   return true;
 }
 
 ModulePass *llvm::createReplacePtrsWithIntsPass() {
   return new ReplacePtrsWithInts();
 }