r313386 - [Sema] Error out early for tags defined inside an enumeration.

[Volodymyr Sapsai via cfe-commits]

Author: vsapsai
Date: Fri Sep 15 12:51:42 2017
New Revision: 313386

URL: http://llvm.org/viewvc/llvm-project?rev=313386&view=rev
Log:
[Sema] Error out early for tags defined inside an enumeration.

This fixes PR28903 by avoiding access check for inner enum constant. We
are performing access check because one enum constant references another
and because enum is defined in CXXRecordDecl. But access check doesn't
work because FindDeclaringClass doesn't expect more than one EnumDecl
and because inner enum has access AS_none due to not being an immediate
child of a record.

The change detects an enum is defined in wrong place and allows to skip
parsing its body. Access check is skipped together with body parsing.
There was no crash in C, added test case to cover the new error.

rdar://problem/28530809

Reviewers: rnk, doug.gregor, rsmith

Reviewed By: doug.gregor

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D37089


Modified:
    cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
    cfe/trunk/lib/Sema/SemaDecl.cpp
    cfe/trunk/test/Sema/enum.c
    cfe/trunk/test/SemaCXX/enum.cpp

Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=313386&r1=313385&r2=313386&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Fri Sep 15 12:51:42 2017
@@ -1335,6 +1335,8 @@ def err_type_defined_in_alias_template :
   "%0 cannot be defined in a type alias template">;
 def err_type_defined_in_condition : Error<
   "%0 cannot be defined in a condition">;
+def err_type_defined_in_enum : Error<
+  "%0 cannot be defined in an enumeration">;
 
 def note_pure_virtual_function : Note<
   "unimplemented pure virtual method %0 in %1">;

Modified: cfe/trunk/lib/Sema/SemaDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDecl.cpp?rev=313386&r1=313385&r2=313386&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDecl.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDecl.cpp Fri Sep 15 12:51:42 2017
@@ -13928,6 +13928,12 @@ CreateNewDecl:
     Invalid = true;
   }
 
+  if (!Invalid && TUK == TUK_Definition && DC->getDeclKind() == Decl::Enum) {
+    Diag(New->getLocation(), diag::err_type_defined_in_enum)
+      << Context.getTagDeclType(New);
+    Invalid = true;
+  }
+
   // Maybe add qualifier info.
   if (SS.isNotEmpty()) {
     if (SS.isSet()) {

Modified: cfe/trunk/test/Sema/enum.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/enum.c?rev=313386&r1=313385&r2=313386&view=diff
==============================================================================
--- cfe/trunk/test/Sema/enum.c (original)
+++ cfe/trunk/test/Sema/enum.c Fri Sep 15 12:51:42 2017
@@ -123,3 +123,14 @@ int NegativeShortTest[NegativeShort == -
 // PR24610
 enum Color { Red, Green, Blue }; // expected-note{{previous use is here}}
 typedef struct Color NewColor; // expected-error {{use of 'Color' with tag type that does not match previous declaration}}
+
+// PR28903
+struct PR28903 {
+  enum {
+    PR28903_A = (enum { // expected-error-re {{'enum PR28903::(anonymous at {{.*}})' cannot be defined in an enumeration}}
+      PR28903_B,
+      PR28903_C = PR28903_B
+    })0
+  };
+  int makeStructNonEmpty;
+};

Modified: cfe/trunk/test/SemaCXX/enum.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/enum.cpp?rev=313386&r1=313385&r2=313386&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/enum.cpp (original)
+++ cfe/trunk/test/SemaCXX/enum.cpp Fri Sep 15 12:51:42 2017
@@ -110,3 +110,13 @@ enum { overflow = 123456 * 234567 };
 // expected-warning at -2 {{not an integral constant expression}}
 // expected-note at -3 {{value 28958703552 is outside the range of representable values}}
 #endif
+
+// PR28903
+struct PR28903 {
+  enum {
+    PR28903_A = (enum { // expected-error-re {{'PR28903::(anonymous enum at {{.*}})' cannot be defined in an enumeration}}
+      PR28903_B,
+      PR28903_C = PR28903_B
+    })
+  };
+};