PNaCl: Strip nonnull attributes from pointer arguments.

R=jfb@chromium.org
TEST= (make -C toolchain_build/out/llvm_x86_64_linux_work -j `nproc` check)
BUG=

Review URL: https://codereview.chromium.org/1042643002

Author: jfbastien

lib/Transforms/NaCl/ReplacePtrsWithInts.cpp

@@ -331,6 +331,8 @@ static AttributeSet RemovePointerAttrs(LLVMContext &Context,
         case Attribute::NoAlias:
         case Attribute::ReadNone:
         case Attribute::ReadOnly:
+        case Attribute::NonNull:
+        case Attribute::Dereferenceable:
           break;
         default:
           AB.addAttribute(*Attr);

test/Transforms/NaCl/replace-ptrs-with-ints.ll

@@ -490,6 +490,16 @@ define void @readonly_readnone(i8* readonly readnone) {
 }
 ; CHECK-LABEL: define void @readonly_readnone(i32)
 
+define nonnull i8* @nonnull_ptr(i8* nonnull) {
+  ret i8* undef
+}
+; CHECK-LABEL: define i32 @nonnull_ptr(i32)
+
+define dereferenceable(16) i8* @dereferenceable_ptr(i8* dereferenceable(8)) {
+  ret i8* undef
+}
+; CHECK-LABEL: define i32 @dereferenceable_ptr(i32)
+
 ; "nounwind" should be preserved.
 define void @nounwind_func_attr() nounwind {
   ret void