[PATCH] D151523: [ASTStructuralEquivalence] Fix crash when ObjCCategoryDecl doesn't have corresponding ObjCInterfaceDecl.

[Volodymyr Sapsai via Phabricator via cfe-commits]

vsapsai created this revision.
vsapsai added reviewers: martong, shafik, ahatanak.
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When this happens, it is invalid code and there is diagnostic

  error: cannot find interface declaration for '...'

But clang shouldn't crash even if code is invalid. Though subsequent
diagnostic can be imperfect because without ObjCInterfaceDecl we don't have
a type for error messages.

rdar://108818430


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D151523

Files:
  clang/lib/AST/ASTStructuralEquivalence.cpp
  clang/unittests/AST/StructuralEquivalenceTest.cpp


Index: clang/unittests/AST/StructuralEquivalenceTest.cpp
===================================================================
--- clang/unittests/AST/StructuralEquivalenceTest.cpp
+++ clang/unittests/AST/StructuralEquivalenceTest.cpp
@@ -1143,6 +1143,18 @@
   EXPECT_FALSE(testStructuralMatch(t));
 }
 
+TEST_F(StructuralEquivalenceObjCCategoryTest, CategoriesWithoutInterfaces) {
+  auto t = makeDecls<ObjCCategoryDecl>("                  @interface A(X) @end",
+                                       "@interface A @end @interface A(X) @end",
+                                       Lang_OBJC, objcCategoryDecl());
+  EXPECT_FALSE(testStructuralMatch(t));
+
+  auto t2 = makeDecls<ObjCCategoryDecl>("@interface A(X) @end",
+                                        "@interface A(X) @end",
+                                        Lang_OBJC, objcCategoryDecl());
+  EXPECT_TRUE(testStructuralMatch(t2));
+}
+
 TEST_F(StructuralEquivalenceObjCCategoryTest, CategoryAndExtension) {
   auto t = makeDecls<ObjCCategoryDecl>("@interface A @end @interface A(X) @end",
                                        "@interface A @end @interface A() @end",
Index: clang/lib/AST/ASTStructuralEquivalence.cpp
===================================================================
--- clang/lib/AST/ASTStructuralEquivalence.cpp
+++ clang/lib/AST/ASTStructuralEquivalence.cpp
@@ -2057,8 +2057,13 @@
   if (!IsStructurallyEquivalent(D1->getIdentifier(), D2->getIdentifier()))
     return false;
 
-  if (!IsStructurallyEquivalent(D1->getClassInterface()->getIdentifier(),
-                                D2->getClassInterface()->getIdentifier()))
+  const ObjCInterfaceDecl *Intf1 = D1->getClassInterface(),
+                          *Intf2 = D2->getClassInterface();
+  if ((Intf1 != nullptr) != (Intf2 != nullptr))
+    return false;
+
+  if (Intf1 &&
+      !IsStructurallyEquivalent(Intf1->getIdentifier(), Intf2->getIdentifier()))
     return false;
 
   // Compare protocols.
@@ -2077,7 +2082,8 @@
     return false;
 
   // Compare ivars.
-  QualType D2Type = Context.ToCtx.getObjCInterfaceType(D2->getClassInterface());
+  QualType D2Type =
+      Intf2 ? Context.ToCtx.getObjCInterfaceType(Intf2) : QualType();
   ObjCCategoryDecl::ivar_iterator Ivar2 = D2->ivar_begin(),
                                   Ivar2End = D2->ivar_end();
   for (ObjCCategoryDecl::ivar_iterator Ivar1 = D1->ivar_begin(),


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