Do not serialize the input Twine more than once

Author: jurahul

llvm/include/llvm/TableGen/CodeGenHelpers.h

@@ -23,8 +23,8 @@ namespace llvm {
 class IfDefEmitter {
 public:
   IfDefEmitter(raw_ostream &OS, const Twine &Name) : Name(Name.str()), OS(OS) {
-    OS << "#ifdef " << Name << "\n"
-       << "#undef " << Name << "\n\n";
+    OS << "#ifdef " << this->Name << "\n"
+       << "#undef " << this->Name << "\n\n";
   }
   ~IfDefEmitter() { OS << "\n#endif // " << Name << "\n\n"; }
 
@@ -38,8 +38,8 @@ class IncludeGuardEmitter {
 public:
   IncludeGuardEmitter(raw_ostream &OS, const Twine &Name)
       : Name(Name.str()), OS(OS) {
-    OS << "#ifndef " << Name << "\n"
-       << "#define " << Name << "\n\n";
+    OS << "#ifndef " << this->Name << "\n"
+       << "#define " << this->Name << "\n\n";
   }
   ~IncludeGuardEmitter() { OS << "\n#endif // " << Name << "\n"; }
 
@@ -53,10 +53,10 @@ class IncludeGuardEmitter {
 // namespace scope.
 class NamespaceEmitter {
 public:
-  NamespaceEmitter(raw_ostream &OS, const Twine &NameUntrimmed)
-      : Name(trim(NameUntrimmed)), OS(OS) {
-    if (!Name.empty())
-      OS << "namespace " << Name << " {\n";
+  NamespaceEmitter(raw_ostream &OS, const Twine &Name)
+      : Name(trim(Name.str())), OS(OS) {
+    if (!this->Name.empty())
+      OS << "namespace " << this->Name << " {\n";
   }
 
   ~NamespaceEmitter() { close(); }
@@ -76,8 +76,7 @@ class NamespaceEmitter {
   // }
   //
   // and cannot use "namespace ::mlir::toy".
-  static std::string trim(const Twine &NameUntrimmed) {
-    std::string Name = NameUntrimmed.str();
+  static std::string trim(std::string Name) {
     StringRef StrRef = Name;
     StrRef.consume_front("::");
     return StrRef.str();

mlir/tools/mlir-tblgen/OpDefinitionsGen.cpp

@@ -4938,7 +4938,7 @@ static void emitOpDefShard(const RecordKeeper &records,
                            ArrayRef<const Record *> defs,
                            const Dialect &dialect, unsigned shardIndex,
                            unsigned shardCount, raw_ostream &os) {
-  IfDefEmitter scope(os, Twine("GET_OP_DEFS_") + Twine(shardIndex));
+  IfDefEmitter scope(os, "GET_OP_DEFS_" + Twine(shardIndex));
 
   // Emit the op registration hook in the first shard.
   const char *const opRegistrationHook =