[lldb][COFF] Map symbols without base+complex type as 'Data' type

Both LLD and GNU ld write global/static variables to the COFF symbol
table with `IMAGE_SYM_TYPE_NULL` and `IMAGE_SYM_DTYPE_NULL` type. Map
these symbols as 'Data' type in the symtab to allow these symbols to be
used in expressions and printable.

Reviewed By: labath, DavidSpickett

Differential Revision: https://reviews.llvm.org/D134585

1 files changed, 7 insertions, 0 deletions

diff --git a/lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp b/lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp
index 6b6177f..61c9b9f 100644
--- a/lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp
+++ b/lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp
@@ -379,6 +379,13 @@ lldb::SymbolType ObjectFilePECOFF::MapSymbolType(uint16_t coff_symbol_type) {
   if (complex_type == llvm::COFF::IMAGE_SYM_DTYPE_FUNCTION) {
     return lldb::eSymbolTypeCode;
   }
+  const auto base_type = coff_symbol_type & 0xff;
+  if (base_type == llvm::COFF::IMAGE_SYM_TYPE_NULL &&
+      complex_type == llvm::COFF::IMAGE_SYM_DTYPE_NULL) {
+    // Unknown type. LLD and GNU ld uses this for variables on MinGW, so
+    // consider these symbols to be data to enable printing.
+    return lldb::eSymbolTypeData;
+  }
   return lldb::eSymbolTypeInvalid;
 }