1 files changed, 15 insertions, 1 deletions
diff --git a/lld/COFF/Symbols.h b/lld/COFF/Symbols.h
index a8e70320b995..1da4df366966 100644
--- a/lld/COFF/Symbols.h
+++ b/lld/COFF/Symbols.h
@@ -69,7 +69,18 @@ public:
   Kind kind() const { return static_cast<Kind>(symbolKind); }
 
   // Returns the symbol name.
-  StringRef getName();
+  StringRef getName() {
+    // COFF symbol names are read lazily for a performance reason.
+    // Non-external symbol names are never used by the linker except for logging
+    // or debugging. Their internal references are resolved not by name but by
+    // symbol index. And because they are not external, no one can refer them by
+    // name. Object files contain lots of non-external symbols, and creating
+    // StringRefs for them (which involves lots of strlen() on the string table)
+    // is a waste of time.
+    if (nameData == nullptr)
+      computeName();
+    return StringRef(nameData, nameSize);
+  }
 
   void replaceKeepingName(Symbol *other, size_t size);
 
@@ -84,6 +95,9 @@ public:
     return symbolKind == LazyArchiveKind || symbolKind == LazyObjectKind;
   }
 
+private:
+  void computeName();
+
 protected:
   friend SymbolTable;
   explicit Symbol(Kind k, StringRef n = "")