Use symbol name when comparing against an externed reloc (#214)

* Use symbol name when comparing against an externed reloc

For partial matching files, often a symbol is externed even though it
should exist in the target object. We can still compare the symbol name,
instead of always returning a mismatch.

* Combine cases, and apply change reloc_eq in code.rs

Author: r-burns

objdiff-core/src/diff/code.rs

@@ -325,12 +325,11 @@ fn reloc_eq(
                     || display_ins_data_literals(left_obj, left_ins)
                         == display_ins_data_literals(right_obj, right_ins))
         }
-        (Some(_), None) => false,
         (None, Some(_)) => {
             // Match if possibly stripped weak symbol
             symbol_name_addend_matches && right_reloc.symbol.flags.contains(SymbolFlag::Weak)
         }
-        (None, None) => symbol_name_addend_matches,
+        (Some(_), None) | (None, None) => symbol_name_addend_matches,
     }
 }
 

objdiff-core/src/diff/data.rs

@@ -53,12 +53,11 @@ fn reloc_eq(
             section_name_eq(left_obj, right_obj, sl, sr)
                 && (symbol_name_addend_matches || address_eq(left, right))
         }
-        (Some(_), None) => false,
         (None, Some(_)) => {
             // Match if possibly stripped weak symbol
             symbol_name_addend_matches && right.symbol.flags.contains(SymbolFlag::Weak)
         }
-        (None, None) => symbol_name_addend_matches,
+        (Some(_), None) | (None, None) => symbol_name_addend_matches,
     }
 }