Sema: Diagnose undefined structs used as Microsoft anonymous structs

Previously, we would not mark structs containing anonymous structs as
invalid.  Later, horrific things would occur when trying to determine
the size of the parent record.

Instead, require the struct to be a complete type when used as an
anonymous struct.  Mark both the anonymous field for the struct and the
parent context as invalid (this is similar to what we do when a struct
contains a field with an incomplete type.)

This fixes PR11847.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@218006 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 1f2cf7bc9f18d0f500f0020b5f7ac86b5acd0410..0aaa60c90fe6d5a002c5302ddb7a0422c9ab12a5 100644 (file)
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -4066,13 +4066,16 @@ Decl *Sema::BuildMicrosoftCAnonymousStruct(Scope *S, DeclSpec &DS,
   TypeSourceInfo *TInfo = GetTypeForDeclarator(Dc, S);
   assert(TInfo && "couldn't build declarator info for anonymous struct");
 
+  auto *ParentDecl = cast<RecordDecl>(CurContext);
+  QualType RecTy = Context.getTypeDeclType(Record);
+
   // Create a declaration for this anonymous struct.
   NamedDecl *Anon = FieldDecl::Create(Context,
-                             cast<RecordDecl>(CurContext),
+                             ParentDecl,
                              DS.getLocStart(),
                              DS.getLocStart(),
                              /*IdentifierInfo=*/nullptr,
-                             Context.getTypeDeclType(Record),
+                             RecTy,
                              TInfo,
                              /*BitWidth=*/nullptr, /*Mutable=*/false,
                              /*InitStyle=*/ICIS_NoInit);
@@ -4088,10 +4091,13 @@ Decl *Sema::BuildMicrosoftCAnonymousStruct(Scope *S, DeclSpec &DS,
   Chain.push_back(Anon);
 
   RecordDecl *RecordDef = Record->getDefinition();
-  if (!RecordDef || InjectAnonymousStructOrUnionMembers(*this, S, CurContext,
-                                                        RecordDef, AS_none,
-                                                        Chain, true))
+  if (RequireCompleteType(Anon->getLocation(), RecTy,
+                          diag::err_field_incomplete) ||
+      InjectAnonymousStructOrUnionMembers(*this, S, CurContext, RecordDef,
+                                          AS_none, Chain, true)) {
     Anon->setInvalidDecl();
+    ParentDecl->setInvalidDecl();
+  }
 
   return Anon;
 }

diff --git a/test/Sema/MicrosoftExtensions.c b/test/Sema/MicrosoftExtensions.c
index 908ec04876e2332c99da34591b079e5259ee3623..e7032305fc07f517c76689a48f3ea0f81fd8086c 100644 (file)
--- a/test/Sema/MicrosoftExtensions.c
+++ b/test/Sema/MicrosoftExtensions.c
@@ -104,6 +104,14 @@ typedef struct {
   AA; // expected-warning {{anonymous structs are a Microsoft extension}}
 } BB;
 
+struct anon_fault {
+  struct undefined; // expected-warning {{anonymous structs are a Microsoft extension}}
+                    // expected-error@-1 {{field has incomplete type 'struct undefined'}}
+                    // expected-note@-2 {{forward declaration of 'struct undefined'}}
+};
+
+const int anon_falt_size = sizeof(struct anon_fault);
+
 __declspec(deprecated("This is deprecated")) enum DE1 { one, two } e1; // expected-note {{'e1' has been explicitly marked deprecated here}}
 struct __declspec(deprecated) DS1 { int i; float f; }; // expected-note {{'DS1' has been explicitly marked deprecated here}}