Rework some move constructors and assignment operators to not simply swap

src/symbols/dwarf/dwarf.hpp

@@ -66,8 +66,12 @@ namespace libdwarf {
         }
 
         ~die_object() {
+            release();
+        }
+
+        void release() {
             if(die) {
-                dwarf_dealloc_die(die);
+                dwarf_dealloc_die(exchange(die, nullptr));
             }
         }
 
@@ -75,16 +79,15 @@ namespace libdwarf {
 
         die_object& operator=(const die_object&) = delete;
 
-        die_object(die_object&& other) noexcept : dbg(other.dbg), die(other.die) {
+        // dbg doesn't strictly have to be st to null but it helps ensure attempts to use the die_object after this to
-            // done for finding mistakes, attempts to use the die_object after this should segfault
+        // segfault. A valid use otherwise would be moved_from.get_sibling() which would get the next CU.
-            // a valid use otherwise would be moved_from.get_sibling() which would get the next CU
+        die_object(die_object&& other) noexcept
-            other.dbg = nullptr;
+            : dbg(exchange(other.dbg, nullptr)), die(exchange(other.die, nullptr)) {}
-            other.die = nullptr;
-        }
 
         die_object& operator=(die_object&& other) noexcept {
-            std::swap(dbg, other.dbg);
+            release();
-            std::swap(die, other.die);
+            dbg = exchange(other.dbg, nullptr);
+            die = exchange(other.die, nullptr);
             return *this;
         }
 

src/symbols/dwarf/dwarf_utils.hpp

@@ -24,12 +24,16 @@ namespace libdwarf {
             }
         }
         ~srcfiles() {
+            release();
+        }
+        void release() {
             if(dw_srcfiles) {
                 for(unsigned i = 0; i < dw_filecount; i++) {
                     dwarf_dealloc(dbg, dw_srcfiles[i], DW_DLA_STRING);
                     dw_srcfiles[i] = nullptr;
                 }
                 dwarf_dealloc(dbg, dw_srcfiles, DW_DLA_LIST);
+                dw_srcfiles = nullptr;
             }
         }
         srcfiles(const srcfiles&) = delete;
@@ -38,9 +42,10 @@ namespace libdwarf {
         }
         srcfiles& operator=(const srcfiles&) = delete;
         srcfiles& operator=(srcfiles&& other) {
-            std::swap(dbg, other.dbg);
+            release();
-            std::swap(dw_srcfiles, other.dw_srcfiles);
+            dbg = exchange(other.dbg, nullptr);
-            std::swap(dw_filecount, other.dw_filecount);
+            dw_srcfiles = exchange(other.dw_srcfiles, nullptr);
+            dw_filecount = exchange(other.dw_filecount, 0);
             return *this;
         }
         // note: dwarf uses 1-indexing
@@ -177,7 +182,11 @@ namespace libdwarf {
             std::vector<line_entry>&& line_entries
         ) : version(version), line_context(line_context), line_entries(std::move(line_entries)) {}
         ~line_table_info() {
+            release();
+        }
+        void release() {
             dwarf_srclines_dealloc_b(line_context);
+            line_context = nullptr;
         }
         line_table_info(const line_table_info&) = delete;
         line_table_info(line_table_info&& other) {
@@ -185,9 +194,10 @@ namespace libdwarf {
         }
         line_table_info& operator=(const line_table_info&) = delete;
         line_table_info& operator=(line_table_info&& other) {
-            std::swap(version, other.version);
+            release();
-            std::swap(line_context, other.line_context);
+            version = other.version;
-            std::swap(line_entries, other.line_entries);
+            line_context = exchange(other.line_context, nullptr);
+            line_entries = std::move(other.line_entries);
             return *this;
         }
     };