Make the -Wreinterpret-base-class logic safe against invalid

declarations at any point. Patch by Alexander Zinenko, and
report by Richard Smith.

llvm-svn: 178098

2 files changed, 62 insertions, 6 deletions

diff --git a/clang/lib/Sema/SemaCast.cpp b/clang/lib/Sema/SemaCast.cpp
index 1dbc9aaca59..0e19adfd28c 100644
--- a/clang/lib/Sema/SemaCast.cpp
+++ b/clang/lib/Sema/SemaCast.cpp
@@ -695,14 +695,15 @@ static void DiagnoseReinterpretUpDownCast(Sema &Self, const Expr *SrcExpr,
   const CXXRecordDecl *SrcRD =
     SrcPointeeRD ? SrcPointeeRD : SrcType->getAsCXXRecordDecl();
 
-  // Examining subobjects for records is only possible if the complete
-  // definition is available.  Also, template instantiation is not allowed here.
-  if(!SrcRD || !SrcRD->isCompleteDefinition())
+  // Examining subobjects for records is only possible if the complete and
+  // valid definition is available.  Also, template instantiation is not
+  // allowed here.
+  if (!SrcRD || !SrcRD->isCompleteDefinition() || SrcRD->isInvalidDecl())
     return;
 
   const CXXRecordDecl *DestRD = DestType->getPointeeCXXRecordDecl();
 
-  if(!DestRD || !DestRD->isCompleteDefinition())
+  if (!DestRD || !DestRD->isCompleteDefinition() || DestRD->isInvalidDecl())
     return;
 
   enum {
@@ -721,7 +722,7 @@ static void DiagnoseReinterpretUpDownCast(Sema &Self, const Expr *SrcExpr,
 
   bool VirtualBase = true;
   bool NonZeroOffset = false;
-  for (CXXBasePaths::const_paths_iterator I = BasePaths.begin(), 
+  for (CXXBasePaths::const_paths_iterator I = BasePaths.begin(),
                                           E = BasePaths.end();
        I != E; ++I) {
     const CXXBasePath &Path = *I;
@@ -734,8 +735,16 @@ static void DiagnoseReinterpretUpDownCast(Sema &Self, const Expr *SrcExpr,
         break;
       const CXXRecordDecl *BaseRD = IElem->Base->getType()->getAsCXXRecordDecl();
       assert(BaseRD && "Base type should be a valid unqualified class type");
+      // Don't check if any base has invalid declaration or has no definition
+      // since it has no layout info.
+      const CXXRecordDecl *Class = IElem->Class,
+                          *ClassDefinition = Class->getDefinition();
+      if (Class->isInvalidDecl() || !ClassDefinition ||
+          !ClassDefinition->isCompleteDefinition())
+        return;
+
       const ASTRecordLayout &DerivedLayout =
-          Self.Context.getASTRecordLayout(IElem->Class);
+          Self.Context.getASTRecordLayout(Class);
       Offset += DerivedLayout.getBaseClassOffset(BaseRD);
     }
     if (!IsVirtual) {
diff --git a/clang/test/SemaCXX/warn-reinterpret-base-class.cpp b/clang/test/SemaCXX/warn-reinterpret-base-class.cpp
index fc7d15c8a34..a7deafeadf2 100644
--- a/clang/test/SemaCXX/warn-reinterpret-base-class.cpp
+++ b/clang/test/SemaCXX/warn-reinterpret-base-class.cpp
@@ -37,6 +37,53 @@ void reinterpret_not_defined_class(B *b, C *c) {
   (void)reinterpret_cast<B &>(*c);
 }
 
+// Do not fail on erroneous classes with fields of incompletely-defined types.
+// Base class is malformed.
+namespace BaseMalformed {
+  struct A; // expected-note {{forward declaration of 'BaseMalformed::A'}}
+  struct B {
+    A a; // expected-error {{field has incomplete type 'BaseMalformed::A'}}
+  };
+  struct C : public B {} c;
+  B *b = reinterpret_cast<B *>(&c);
+} // end anonymous namespace
+
+// Child class is malformed.
+namespace ChildMalformed {
+  struct A; // expected-note {{forward declaration of 'ChildMalformed::A'}}
+  struct B {};
+  struct C : public B {
+    A a; // expected-error {{field has incomplete type 'ChildMalformed::A'}}
+  } c;
+  B *b = reinterpret_cast<B *>(&c);
+} // end anonymous namespace
+
+// Base class outside upcast base-chain is malformed.
+namespace BaseBaseMalformed {
+  struct A; // expected-note {{forward declaration of 'BaseBaseMalformed::A'}}
+  struct Y {};
+  struct X { A a; }; // expected-error {{field has incomplete type 'BaseBaseMalformed::A'}}
+  struct B : Y, X {};
+  struct C : B {} c;
+  B *p = reinterpret_cast<B*>(&c);
+}
+
+namespace InheritanceMalformed {
+  struct A; // expected-note {{forward declaration of 'InheritanceMalformed::A'}}
+  struct B : A {}; // expected-error {{base class has incomplete type}}
+  struct C : B {} c;
+  B *p = reinterpret_cast<B*>(&c);
+}
+
+// Virtual base class outside upcast base-chain is malformed.
+namespace VBaseMalformed{
+  struct A; // expected-note {{forward declaration of 'VBaseMalformed::A'}}
+  struct X { A a; };  // expected-error {{field has incomplete type 'VBaseMalformed::A'}}
+  struct B : public virtual X {};
+  struct C : B {} c;
+  B *p = reinterpret_cast<B*>(&c);
+}
+
 void reinterpret_not_updowncast(A *pa, const A *pca, A &a, const A &ca) {
   (void)*reinterpret_cast<C *>(pa);
   (void)*reinterpret_cast<const C *>(pa);