Revert r315148 [TableGen] Avoid unnecessary std::string creations

I'm about to commit a patch that makes them necessary for getPredCode() and
it would be strange for getPredCode() and getImmCode() to require different
usage.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@315733 91177308-0d34-0410-b5e6-96231b3b80d8

utils/TableGen/CodeGenDAGPatterns.cpp

@@ -854,11 +854,11 @@ TreePredicateFn::TreePredicateFn(TreePattern *N) : PatFragRec(N) {
         ".td file corrupt: can't have a node predicate *and* an imm predicate");
 }
 
-StringRef TreePredicateFn::getPredCode() const {
+std::string TreePredicateFn::getPredCode() const {
   return PatFragRec->getRecord()->getValueAsString("PredicateCode");
 }
 
-StringRef TreePredicateFn::getImmCode() const {
+std::string TreePredicateFn::getImmCode() const {
   return PatFragRec->getRecord()->getValueAsString("ImmediateCode");
 }
 
@@ -880,16 +880,16 @@ std::string TreePredicateFn::getFnName() const {
 /// appropriate.
 std::string TreePredicateFn::getCodeToRunOnSDNode() const {
   // Handle immediate predicates first.
-  StringRef ImmCode = getImmCode();
+  std::string ImmCode = getImmCode();
   if (!ImmCode.empty()) {
     std::string Result =
       "    int64_t Imm = cast<ConstantSDNode>(Node)->getSExtValue();\n";
-    return Result + ImmCode.str();
+    return Result + ImmCode;
   }
 
   // Handle arbitrary node predicates.
   assert(!getPredCode().empty() && "Don't have any predicate code!");
-  StringRef ClassName;
+  std::string ClassName;
   if (PatFragRec->getOnlyTree()->isLeaf())
     ClassName = "SDNode";
   else {
@@ -900,9 +900,9 @@ std::string TreePredicateFn::getCodeToRunOnSDNode() const {
   if (ClassName == "SDNode")
     Result = "    SDNode *N = Node;\n";
   else
-    Result = "    auto *N = cast<" + ClassName.str() + ">(Node);\n";
+    Result = "    auto *N = cast<" + ClassName + ">(Node);\n";
 
-  return Result + getPredCode().str();
+  return Result + getPredCode();
 }
 
 //===----------------------------------------------------------------------===//
@@ -2564,7 +2564,7 @@ CodeGenDAGPatterns::CodeGenDAGPatterns(RecordKeeper &R) :
   VerifyInstructionFlags();
 }
 
-Record *CodeGenDAGPatterns::getSDNodeNamed(StringRef Name) const {
+Record *CodeGenDAGPatterns::getSDNodeNamed(const std::string &Name) const {
   Record *N = Records.getDef(Name);
   if (!N || !N->isSubClassOf("SDNode"))
     PrintFatalError("Error getting SDNode '" + Name + "'!");

utils/TableGen/CodeGenDAGPatterns.h

@@ -452,8 +452,8 @@ class TreePredicateFn {
   /// getImmediatePredicateCode - Return the code that evaluates this pattern if
   /// this is an immediate predicate.  It is an error to call this on a
   /// non-immediate pattern.
-  StringRef getImmediatePredicateCode() const {
-    StringRef Result = getImmCode();
+  std::string getImmediatePredicateCode() const {
+    std::string Result = getImmCode();
     assert(!Result.empty() && "Isn't an immediate pattern!");
     return Result;
   }
@@ -476,8 +476,8 @@ class TreePredicateFn {
   std::string getCodeToRunOnSDNode() const;
 
 private:
-  StringRef getPredCode() const;
-  StringRef getImmCode() const;
+  std::string getPredCode() const;
+  std::string getImmCode() const;
 };
 
 
@@ -995,7 +995,7 @@ class CodeGenDAGPatterns {
   const CodeGenTarget &getTargetInfo() const { return Target; }
   const TypeSetByHwMode &getLegalTypes() const { return LegalVTS; }
 
-  Record *getSDNodeNamed(StringRef Name) const;
+  Record *getSDNodeNamed(const std::string &Name) const;
 
   const SDNodeInfo &getSDNodeInfo(Record *R) const {
     auto F = SDNodes.find(R);