The AST importer had a bug where it would enter into an infinite recursion

when importing type parameter lists.  The reason is that type parameters
have their DeclContexts set to the interface that is parameterized with those
types, and the importer would follow that loop and blow the stack out.

I've changed the way this works so that the type parameters are only imported
after the interface that contains them has been registered via the Imported()
function.

This is tested by LLDB.

<rdar://problem/20315663>

llvm-svn: 241556

1 files changed, 10 insertions, 4 deletions

diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
index 8460030b4b2..35c0f690db8 100644
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -3491,13 +3491,16 @@ Decl *ASTNodeImporter::VisitObjCCategoryDecl(ObjCCategoryDecl *D) {
                                        Importer.Import(D->getCategoryNameLoc()), 
                                           Name.getAsIdentifierInfo(),
                                           ToInterface,
-                                          ImportObjCTypeParamList(
-                                            D->getTypeParamList()),
+                                          /*TypeParamList=*/nullptr,
                                        Importer.Import(D->getIvarLBraceLoc()),
                                        Importer.Import(D->getIvarRBraceLoc()));
     ToCategory->setLexicalDeclContext(LexicalDC);
     LexicalDC->addDeclInternal(ToCategory);
     Importer.Imported(D, ToCategory);
+    // Import the type parameter list after calling Imported, to avoid
+    // loops when bringing in their DeclContext.
+    ToCategory->setTypeParamList(ImportObjCTypeParamList(
+                                   D->getTypeParamList()));
     
     // Import protocols
     SmallVector<ObjCProtocolDecl *, 4> Protocols;
@@ -3819,14 +3822,17 @@ Decl *ASTNodeImporter::VisitObjCInterfaceDecl(ObjCInterfaceDecl *D) {
     ToIface = ObjCInterfaceDecl::Create(Importer.getToContext(), DC,
                                         Importer.Import(D->getAtStartLoc()),
                                         Name.getAsIdentifierInfo(),
-                                        ImportObjCTypeParamList(
-                                          D->getTypeParamListAsWritten()),
+                                        /*TypeParamList=*/nullptr,
                                         /*PrevDecl=*/nullptr, Loc,
                                         D->isImplicitInterfaceDecl());
     ToIface->setLexicalDeclContext(LexicalDC);
     LexicalDC->addDeclInternal(ToIface);
   }
   Importer.Imported(D, ToIface);
+  // Import the type parameter list after calling Imported, to avoid
+  // loops when bringing in their DeclContext.
+  ToIface->setTypeParamList(ImportObjCTypeParamList(
+                              D->getTypeParamListAsWritten()));
   
   if (D->isThisDeclarationADefinition() && ImportDefinition(D, ToIface))
     return nullptr;