add function to get global variable address

src/symbol.cpp

@@ -56,3 +56,62 @@ bool Symbol::is_integer_type(Dwarf_Debug dbg, Dwarf_Die die) {
   dwarf_dealloc(dbg, type_die, DW_DLA_DIE);
   return is_integer;
 }
+
+Dwarf_Addr Symbol::get_global_var_addr(Dwarf_Debug dbg, Dwarf_Die die) {
+  Dwarf_Error err;
+  Dwarf_Attribute loc_attr;
+  Dwarf_Addr addr = 0;
+
+  // Get the location attribute
+  if (dwarf_attr(die, DW_AT_location, &loc_attr, &err) != DW_DLV_OK)
+    return 0;
+
+  // Get location list
+  Dwarf_Loc_Head_c loclist_head;
+  Dwarf_Unsigned locentry_count;
+
+  if (dwarf_get_loclist_c(loc_attr, &loclist_head, &locentry_count, &err) == DW_DLV_OK) {
+    // Iterate through location entries
+    for (Dwarf_Unsigned i = 0; i < locentry_count; i++) {
+      Dwarf_Small loclist_lkind;
+      Dwarf_Small lle_value;
+      Dwarf_Unsigned rawval1, rawval2;
+      Dwarf_Bool debug_addr_unavailable;
+      Dwarf_Addr lopc, hipc;
+      Dwarf_Unsigned loclist_expr_op_count;
+      Dwarf_Locdesc_c locdesc_entry;
+      Dwarf_Unsigned expression_offset;
+      Dwarf_Unsigned locdesc_offset;
+
+      if (dwarf_get_locdesc_entry_d(loclist_head, i, &lle_value, &rawval1, &rawval2,
+                                    &debug_addr_unavailable, &lopc, &hipc,
+                                    &loclist_expr_op_count, &locdesc_entry,
+                                    &loclist_lkind, &expression_offset, &locdesc_offset,
+                                    &err) == DW_DLV_OK) {
+
+        // Check for simple address location
+        for (Dwarf_Unsigned j = 0; j < loclist_expr_op_count; j++) {
+          Dwarf_Small op;
+          Dwarf_Unsigned opd1, opd2, opd3;
+          Dwarf_Unsigned offsetforbranch;
+
+          if (dwarf_get_location_op_value_c(locdesc_entry, j, &op, &opd1, &opd2, &opd3,
+                                           &offsetforbranch, &err) == DW_DLV_OK) {
+            if (op == DW_OP_addr) {
+              addr = opd1;
+              break;
+            }
+          }
+        }
+      }
+
+      if (addr != 0)
+        break;
+    }
+
+    dwarf_dealloc_loc_head_c(loclist_head);
+  }
+
+  dwarf_dealloc(dbg, loc_attr, DW_DLA_ATTR);
+  return addr;
+}