[Interpreter] Implment Interpreter::Restore to clean up lookup table

[junaire]

Summary

This patch adds a new method to the clang::Interpreter, enables us to
explictly clean up the lookup table when doing recovery.
Signed-off-by: Jun Zhang <[e-mail]>

[junaire]

Format the patch

[junaire]

work moved to D126682, so abandon this

clang/include/clang/Interpreter/Interpreter.h

llvm::Error ParseAndExecute(llvm::StringRef Code) {
     auto PTU = Parse(Code);
     if (!PTU)
       return PTU.takeError();
     if (PTU->TheModule)
       return Execute(*PTU);
     return llvm::Error::success();
   }
 
+  void Restore(PartialTranslationUnit &PTU);
+
   /// \returns the \c JITTargetAddress of a \c GlobalDecl. This interface uses
   /// the CodeGenModule's internal mangling cache to avoid recomputing the
   /// mangled name.
   llvm::Expected<llvm::JITTargetAddress> getSymbolAddress(GlobalDecl GD) const;
 
   /// \returns the \c JITTargetAddress of a given name as written in the IR.
   llvm::Expected<llvm::JITTargetAddress>
   getSymbolAddress(llvm::StringRef IRName) const;

clang/lib/Interpreter/IncrementalParser.h

public:
   ///\returns a \c PartialTranslationUnit which holds information about the
   /// \c TranslationUnitDecl and \c llvm::Module corresponding to the input.
   llvm::Expected<PartialTranslationUnit &> Parse(llvm::StringRef Input);
 
   /// Uses the CodeGenModule mangled name cache and avoids recomputing.
   ///\returns the mangled name of a \c GD.
   llvm::StringRef GetMangledName(GlobalDecl GD) const;
 
+  void Restore(PartialTranslationUnit &PTU);
+
 private:
   llvm::Expected<PartialTranslationUnit &> ParseOrWrapTopLevelDecl();
 };
 } // end namespace clang
 
 #endif // LLVM_CLANG_LIB_INTERPRETER_INCREMENTALPARSER_H

clang/lib/Interpreter/IncrementalParser.cpp

CG->StartModule("incr_module_" + std::to_string(PTUs.size()),
                     M->getContext());
 
     PTU->TheModule = std::move(M);
   }
 
   return PTU;
 }
 
+void IncrementalParser::Restore(PartialTranslationUnit &PTU) {
+  TranslationUnitDecl *MostRecentTU = PTU.TUPart;
+  TranslationUnitDecl *FirstTU = MostRecentTU->getFirstDecl();
+  if (StoredDeclsMap *Map = FirstTU->getLookupPtr()) {
+    for (auto I = Map->begin(); I != Map->end(); ++I) {
+      StoredDeclsList &List = I->second;
+      DeclContextLookupResult R = List.getLookupResult();
+      for (NamedDecl *D : R) {
+        if (D->getTranslationUnitDecl() == MostRecentTU) {
+          List.remove(D);
+        }
+      }
+      if (List.isNull())
+        Map->erase(I);
+    }
+  }
+}
+
 llvm::StringRef IncrementalParser::GetMangledName(GlobalDecl GD) const {
   CodeGenerator *CG = getCodeGen(Act.get());
   assert(CG);
   return CG->GetMangledName(GD);
 }
 
 } // end namespace clang

clang/lib/Interpreter/Interpreter.cpp

if (auto Err = IncrExecutor->addModule(std::move(T.TheModule)))
     return Err;
 
   if (auto Err = IncrExecutor->runCtors())
     return Err;
 
   return llvm::Error::success();
 }
 
+void Interpreter::Restore(PartialTranslationUnit &PTU) {
+  IncrParser->Restore(PTU);
+}
+
 llvm::Expected<llvm::JITTargetAddress>
 Interpreter::getSymbolAddress(GlobalDecl GD) const {
   if (!IncrExecutor)
     return llvm::make_error<llvm::StringError>("Operation failed. "
                                                "No execution engine",
                                                std::error_code());
   llvm::StringRef MangledName = IncrParser->GetMangledName(GD);
   return getSymbolAddress(MangledName);