[ASTImporter][LLDB] Modifying ImportDeclContext(...) to ensure that we complete each FieldDecl of a RecordDecl when we are importing the definiton

This fix was motivated by a crashes in expression parsing during code generation in which we had a RecordDecl that had incomplete FieldDecl. During code generation when computing the layout for the RecordDecl we crash because we have several incomplete FieldDecl.

This fixes the issue by assuring that during ImportDefinition(...) for a RecordDecl we also import the definitions for each FieldDecl.

Differential Revision: https://reviews.llvm.org/D71378

3 files changed, 44 insertions, 1 deletions

diff --git a/lldb/packages/Python/lldbsuite/test/commands/expression/codegen-crash-typedefdecl-not-in_declcontext/TestCodegenCrashTypedefDeclNotInDeclContext.py b/lldb/packages/Python/lldbsuite/test/commands/expression/codegen-crash-typedefdecl-not-in_declcontext/TestCodegenCrashTypedefDeclNotInDeclContext.py
new file mode 100644
index 00000000000..f08c0dcbda9
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/commands/expression/codegen-crash-typedefdecl-not-in_declcontext/TestCodegenCrashTypedefDeclNotInDeclContext.py
@@ -0,0 +1,4 @@
+from lldbsuite.test import lldbinline
+from lldbsuite.test import decorators
+
+lldbinline.MakeInlineTest(__file__, globals(), [])
diff --git a/lldb/packages/Python/lldbsuite/test/commands/expression/codegen-crash-typedefdecl-not-in_declcontext/main.cpp b/lldb/packages/Python/lldbsuite/test/commands/expression/codegen-crash-typedefdecl-not-in_declcontext/main.cpp
new file mode 100644
index 00000000000..e4f6600eab2
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/commands/expression/codegen-crash-typedefdecl-not-in_declcontext/main.cpp
@@ -0,0 +1,39 @@
+// This is a reproducer for a crash in codegen. It happens when we have a
+// RecordDecl used in an expression and one of the FieldDecl are not complete.
+// This case happens when:
+// - A RecordDecl (E) has a FieldDecl which is a reference member variable
+// - The underlying type of the FieldDec is a TypedefDecl
+// - The typedef refers to a ClassTemplateSpecialization (DWrapper)
+// - The typedef is not present in the DeclContext of B
+// - The typedef shows up as a return value of a member function of E (f())
+template <typename T> struct DWrapper {};
+
+struct D {};
+
+namespace NS {
+typedef DWrapper<D> DW;
+}
+
+struct B {
+  NS::DW spd;
+  int a = 0;
+};
+
+struct E {
+  E(B &b) : b_ref(b) {}
+  NS::DW f() { return {}; };
+  void g() {
+    return; //%self.expect("p b_ref", substrs=['(B) $0 =', '(spd = NS::DW', 'a = 0)'])
+  }
+
+  B &b_ref;
+};
+
+int main() {
+  B b;
+  E e(b);
+
+  e.g();
+
+  return 0;
+}
diff --git a/lldb/packages/Python/lldbsuite/test/commands/expression/completion-crash-incomplete-record/TestCompletionCrashIncompleteRecord.py b/lldb/packages/Python/lldbsuite/test/commands/expression/completion-crash-incomplete-record/TestCompletionCrashIncompleteRecord.py
index 68bd864c008..f08c0dcbda9 100644
--- a/lldb/packages/Python/lldbsuite/test/commands/expression/completion-crash-incomplete-record/TestCompletionCrashIncompleteRecord.py
+++ b/lldb/packages/Python/lldbsuite/test/commands/expression/completion-crash-incomplete-record/TestCompletionCrashIncompleteRecord.py
@@ -1,4 +1,4 @@
 from lldbsuite.test import lldbinline
 from lldbsuite.test import decorators
 
-lldbinline.MakeInlineTest(__file__, globals(), [decorators.skipIf(bugnumber="rdar://53756116")])
+lldbinline.MakeInlineTest(__file__, globals(), [])