[ORC] Pass symbol name to discard by const reference.

This saves some unnecessary atomic ref-counting operations.

llvm-svn: 343927

Author: lhames

llvm/include/llvm/ExecutionEngine/Orc/Core.h

@@ -255,7 +255,7 @@ class MaterializationUnit {
 
   /// Called by JITDylibs to notify MaterializationUnits that the given symbol
   /// has been overridden.
-  void doDiscard(const JITDylib &JD, SymbolStringPtr Name) {
+  void doDiscard(const JITDylib &JD, const SymbolStringPtr &Name) {
     SymbolFlags.erase(Name);
     discard(JD, std::move(Name));
   }
@@ -275,7 +275,7 @@ class MaterializationUnit {
   ///        from the source (e.g. if the source is an LLVM IR Module and the
   ///        symbol is a function, delete the function body or mark it available
   ///        externally).
-  virtual void discard(const JITDylib &JD, SymbolStringPtr Name) = 0;
+  virtual void discard(const JITDylib &JD, const SymbolStringPtr &Name) = 0;
 };
 
 using MaterializationUnitList =
@@ -293,7 +293,7 @@ class AbsoluteSymbolsMaterializationUnit : public MaterializationUnit {
 
 private:
   void materialize(MaterializationResponsibility R) override;
-  void discard(const JITDylib &JD, SymbolStringPtr Name) override;
+  void discard(const JITDylib &JD, const SymbolStringPtr &Name) override;
   static SymbolFlagsMap extractFlags(const SymbolMap &Symbols);
 
   SymbolMap Symbols;
@@ -344,7 +344,7 @@ class ReExportsMaterializationUnit : public MaterializationUnit {
 
 private:
   void materialize(MaterializationResponsibility R) override;
-  void discard(const JITDylib &JD, SymbolStringPtr Name) override;
+  void discard(const JITDylib &JD, const SymbolStringPtr &Name) override;
   static SymbolFlagsMap extractFlags(const SymbolAliasMap &Aliases);
 
   JITDylib *SourceJD = nullptr;

llvm/include/llvm/ExecutionEngine/Orc/Layer.h

@@ -96,7 +96,7 @@ class IRMaterializationUnit : public MaterializationUnit {
   SymbolNameToDefinitionMap SymbolToDefinition;
 
 private:
-  void discard(const JITDylib &JD, SymbolStringPtr Name) override;
+  void discard(const JITDylib &JD, const SymbolStringPtr &Name) override;
 };
 
 /// MaterializationUnit that materializes modules by calling the 'emit' method
@@ -158,7 +158,7 @@ class BasicObjectLayerMaterializationUnit : public MaterializationUnit {
 private:
 
   void materialize(MaterializationResponsibility R) override;
-  void discard(const JITDylib &JD, SymbolStringPtr Name) override;
+  void discard(const JITDylib &JD, const SymbolStringPtr &Name) override;
 
   ObjectLayer &L;
   VModuleKey K;

llvm/include/llvm/ExecutionEngine/Orc/LazyReexports.h

@@ -165,7 +165,7 @@ class LazyReexportsMaterializationUnit : public MaterializationUnit {
 
 private:
   void materialize(MaterializationResponsibility R) override;
-  void discard(const JITDylib &JD, SymbolStringPtr Name) override;
+  void discard(const JITDylib &JD, const SymbolStringPtr &Name) override;
   static SymbolFlagsMap extractFlags(const SymbolAliasMap &Aliases);
 
   LazyCallThroughManager &LCTManager;

llvm/lib/ExecutionEngine/Orc/CompileOnDemandLayer.cpp

@@ -85,7 +85,7 @@ class PartitioningIRMaterializationUnit : public IRMaterializationUnit {
                          std::move(SymbolToDefinition));
   }
 
-  void discard(const JITDylib &V, SymbolStringPtr Name) override {
+  void discard(const JITDylib &V, const SymbolStringPtr &Name) override {
     // All original symbols were materialized by the CODLayer and should be
     // final. The function bodies provided by M should never be overridden.
     llvm_unreachable("Discard should never be called on an "

llvm/lib/ExecutionEngine/Orc/Core.cpp

@@ -489,7 +489,7 @@ void AbsoluteSymbolsMaterializationUnit::materialize(
 }
 
 void AbsoluteSymbolsMaterializationUnit::discard(const JITDylib &JD,
-                                                 SymbolStringPtr Name) {
+                                                 const SymbolStringPtr &Name) {
   assert(Symbols.count(Name) && "Symbol is not part of this MU");
   Symbols.erase(Name);
 }
@@ -637,7 +637,7 @@ void ReExportsMaterializationUnit::materialize(
 }
 
 void ReExportsMaterializationUnit::discard(const JITDylib &JD,
-                                           SymbolStringPtr Name) {
+                                           const SymbolStringPtr &Name) {
   assert(Aliases.count(Name) &&
          "Symbol not covered by this MaterializationUnit");
   Aliases.erase(Name);

llvm/lib/ExecutionEngine/Orc/IndirectionUtils.cpp

@@ -41,7 +41,7 @@ class CompileCallbackMaterializationUnit : public orc::MaterializationUnit {
     R.emit();
   }
 
-  void discard(const JITDylib &JD, SymbolStringPtr Name) override {
+  void discard(const JITDylib &JD, const SymbolStringPtr &Name) override {
     llvm_unreachable("Discard should never occur on a LMU?");
   }
 

llvm/lib/ExecutionEngine/Orc/Layer.cpp

@@ -53,7 +53,8 @@ StringRef IRMaterializationUnit::getName() const {
   return "<null module>";
 }
 
-void IRMaterializationUnit::discard(const JITDylib &JD, SymbolStringPtr Name) {
+void IRMaterializationUnit::discard(const JITDylib &JD,
+                                    const SymbolStringPtr &Name) {
   LLVM_DEBUG(JD.getExecutionSession().runSessionLocked([&]() {
     dbgs() << "In " << JD.getName() << " discarding " << *Name << " from MU@"
            << this << " (" << getName() << ")\n";
@@ -145,7 +146,7 @@ void BasicObjectLayerMaterializationUnit::materialize(
 }
 
 void BasicObjectLayerMaterializationUnit::discard(const JITDylib &JD,
-                                                  SymbolStringPtr Name) {
+                                                  const SymbolStringPtr &Name) {
   // FIXME: Support object file level discard. This could be done by building a
   //        filter to pass to the object layer along with the object itself.
 }

llvm/lib/ExecutionEngine/Orc/LazyReexports.cpp

@@ -187,7 +187,7 @@ void LazyReexportsMaterializationUnit::materialize(
 }
 
 void LazyReexportsMaterializationUnit::discard(const JITDylib &JD,
-                                               SymbolStringPtr Name) {
+                                               const SymbolStringPtr &Name) {
   assert(CallableAliases.count(Name) &&
          "Symbol not covered by this MaterializationUnit");
   CallableAliases.erase(Name);

llvm/unittests/ExecutionEngine/Orc/OrcTestCommon.h

@@ -112,7 +112,8 @@ class SimpleMaterializationUnit : public orc::MaterializationUnit {
     Materialize(std::move(R));
   }
 
-  void discard(const orc::JITDylib &JD, orc::SymbolStringPtr Name) override {
+  void discard(const orc::JITDylib &JD,
+               const orc::SymbolStringPtr &Name) override {
     if (Discard)
       Discard(JD, std::move(Name));
     else