[Parse] Parse '#pragma clang attribute' as an external-declaration

Previously, we parsed it only in the top level, which excludes namespaces and
extern "C" blocks.

rdar://problem/48818890

Differential revision: https://reviews.llvm.org/D59282

llvm-svn: 356075

clang/lib/Parse/Parser.cpp

@@ -583,10 +583,6 @@ bool Parser::ParseTopLevelDecl(DeclGroupPtrTy &Result) {
     ConsumeAnnotationToken();
     return false;
 
-  case tok::annot_pragma_attribute:
-    HandlePragmaAttribute();
-    return false;
-
   case tok::eof:
     // Late template parsing can begin.
     if (getLangOpts().DelayedTemplateParsing)
@@ -698,6 +694,9 @@ Parser::ParseExternalDeclaration(ParsedAttributesWithRange &attrs,
   case tok::annot_pragma_dump:
     HandlePragmaDump();
     return nullptr;
+  case tok::annot_pragma_attribute:
+    HandlePragmaAttribute();
+    return nullptr;
   case tok::semi:
     // Either a C++11 empty-declaration or attribute-declaration.
     SingleDecl =

clang/test/Parser/pragma-attribute-context.cpp

@@ -0,0 +1,34 @@
+// RUN: %clang_cc1 -verify -std=c++11 %s
+// RUN: %clang_cc1 -xobjective-c++ -verify -std=c++11 %s
+
+#define BEGIN_PRAGMA _Pragma("clang attribute push (__attribute__((availability(macos, introduced=1000))), apply_to=function)")
+#define END_PRAGMA _Pragma("clang attribute pop")
+
+extern "C" {
+BEGIN_PRAGMA
+int f(); // expected-note{{'f' has been marked as being introduced in macOS 1000 here}}
+END_PRAGMA
+}
+
+namespace my_ns {
+BEGIN_PRAGMA
+int g(); // expected-note{{'g' has been marked as being introduced in macOS 1000 here}}
+END_PRAGMA
+namespace nested {
+BEGIN_PRAGMA
+int h(); // expected-note{{'h' has been marked as being introduced in macOS 1000 here}}
+END_PRAGMA
+}
+}
+
+int a = f(); // expected-warning{{'f' is only available on macOS 1000 or newer}} expected-note{{annotate 'a'}}
+int b = my_ns::g(); // expected-warning{{'g' is only available on macOS 1000 or newer}} expected-note{{annotate 'b'}}
+int c = my_ns::nested::h(); // expected-warning{{'h' is only available on macOS 1000 or newer}} expected-note{{annotate 'c'}}
+
+struct InStruct {
+  // FIXME: This asserts in Objective-C++!
+  // FIXME: This is a horrible diagnostic!
+#ifndef __OBJC__
+  BEGIN_PRAGMA // expected-error {{expected member name or ';' after declaration specifiers}}
+#endif
+};