[lldb][DWARFASTParserClang] GetClangDeclForDIE: don't create VarDecl for static data members

lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp

@@ -142,6 +142,18 @@ static bool ShouldIgnoreArtificialField(llvm::StringRef FieldName) {
          || FieldName.starts_with("_vptr.");
 }
 
+/// Returns true for C++ constructs represented by clang::CXXRecordDecl
+static bool TagIsRecordType(dw_tag_t tag) {
+  switch (tag) {
+  case DW_TAG_class_type:
+  case DW_TAG_structure_type:
+  case DW_TAG_union_type:
+    return true;
+  default:
+    return false;
+  }
+}
+
 TypeSP DWARFASTParserClang::ParseTypeFromClangModule(const SymbolContext &sc,
                                                      const DWARFDIE &die,
                                                      Log *log) {
@@ -3293,12 +3305,19 @@ clang::Decl *DWARFASTParserClang::GetClangDeclForDIE(const DWARFDIE &die) {
     return nullptr;
 
   switch (die.Tag()) {
-  case DW_TAG_variable:
   case DW_TAG_constant:
   case DW_TAG_formal_parameter:
   case DW_TAG_imported_declaration:
   case DW_TAG_imported_module:
     break;
+  case DW_TAG_variable:
+    // This means 'die' is a C++ static data member.
+    // We don't want to create decls for such members
+    // here.
+    if (auto parent = die.GetParent();
+        parent.IsValid() && TagIsRecordType(parent.Tag()))
+      return nullptr;
+    break;
   default:
     return nullptr;
   }

lldb/test/Shell/SymbolFile/DWARF/Inputs/dwo-static-data-member.cpp

@@ -0,0 +1,8 @@
+struct NoCtor {
+  NoCtor();
+  static int i;
+};
+
+int NoCtor::i = 15;
+
+int main() { return NoCtor::i; }

lldb/test/Shell/SymbolFile/DWARF/dwo-static-data-member-access.test

@@ -0,0 +1,24 @@
+# In DWARFv5, C++ static data members are represented
+# as DW_TAG_variable. We make sure LLDB's expression
+# evaluator doesn't crash when trying to parse such
+# a DW_TAG_variable DIE, whose parent DIE is only
+# a forward declaration.
+
+# RUN: %clangxx_host %S/Inputs/dwo-static-data-member.cpp \
+# RUN:   -g -gdwarf-5 -gsplit-dwarf -flimit-debug-info -o %t
+# RUN: %lldb %t -s %s -o exit 2>&1 | FileCheck %s
+
+breakpoint set -n main
+process launch
+
+# CHECK: Process {{.*}} stopped
+
+# FIXME: The expression evaluator tries to attach
+# the static member's VarDecl to the NoCtor RecordDecl
+# before passing the AST to clang; this requires the
+# RecordDecl to be a full definition. But the debug-info
+# only contains forward declaration for NoCtor. So
+# LLDB fails to evaluate the expression.
+expression NoCtor::i
+# CHECK-LABEL: expression NoCtor::i
+# CHECK:       use of undeclared identifier 'NoCtor'