Add a warning for missing '#pragma pack (pop)' and suspicious uses

of '#pragma pack' in included files

This commit adds a new -Wpragma-pack warning. It warns in the following cases:

- When a translation unit is missing terminating #pragma pack (pop) directives.
- When entering an included file if the current alignment value as determined
  by '#pragma pack' directives is different from the default alignment value.
- When leaving an included file that changed the state of the current alignment
  value.

rdar://10184173

Differential Revision: https://reviews.llvm.org/D35484


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@308327 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 12 insertions, 1 deletions

diff --git a/include/clang/Basic/DiagnosticGroups.td b/include/clang/Basic/DiagnosticGroups.td
index 3a0564806b..adb71fa9d5 100644
--- a/include/clang/Basic/DiagnosticGroups.td
+++ b/include/clang/Basic/DiagnosticGroups.td
@@ -467,8 +467,9 @@ def IgnoredPragmaIntrinsic : DiagGroup<"ignored-pragma-intrinsic">;
 def UnknownPragmas : DiagGroup<"unknown-pragmas">;
 def IgnoredPragmas : DiagGroup<"ignored-pragmas", [IgnoredPragmaIntrinsic]>;
 def PragmaClangAttribute : DiagGroup<"pragma-clang-attribute">;
+def PragmaPack : DiagGroup<"pragma-pack">;
 def Pragmas : DiagGroup<"pragmas", [UnknownPragmas, IgnoredPragmas,
-                                    PragmaClangAttribute]>;
+                                    PragmaClangAttribute, PragmaPack]>;
 def UnknownWarningOption : DiagGroup<"unknown-warning-option">;
 def NSobjectAttribute : DiagGroup<"NSObject-attribute">;
 def IndependentClassAttribute : DiagGroup<"IndependentClass-attribute">;
diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index 09ad1c5b2a..aeeef5cae6 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -712,6 +712,16 @@ def err_pragma_options_align_mac68k_target_unsupported : Error<
 def warn_pragma_pack_invalid_alignment : Warning<
   "expected #pragma pack parameter to be '1', '2', '4', '8', or '16'">,
   InGroup<IgnoredPragmas>;
+def warn_pragma_pack_non_default_at_include : Warning<
+  "non-default #pragma pack value might change the alignment of struct or "
+  "union members in the included file">, InGroup<PragmaPack>;
+def warn_pragma_pack_modified_after_include : Warning<
+  "the current #pragma pack aligment value is modified in the included "
+  "file">, InGroup<PragmaPack>;
+def warn_pragma_pack_no_pop_eof : Warning<"unterminated "
+  "'#pragma pack (push, ...)' at end of file">, InGroup<PragmaPack>;
+def note_pragma_pack_here : Note<
+  "previous '#pragma pack' directive that modifies alignment is here">;
 // Follow the Microsoft implementation.
 def warn_pragma_pack_show : Warning<"value of #pragma pack(show) == %0">;
 def warn_pragma_pack_pop_identifer_and_alignment : Warning<