Access parent from a child interpreter, and const correct gCling.

include/cling/Interpreter/DynamicLookupRuntimeUniverse.h

@@ -21,7 +21,7 @@ namespace cling {
 
 /// \brief Contains declarations for cling's runtime.
 namespace runtime {
-  extern Interpreter* gCling;
+  extern Interpreter* const gCling;
 
   /// \brief Provides builtins, which are neccessary for the dynamic scopes
   /// and runtime bindings. These builtins should be used for other purposes.

include/cling/Interpreter/Interpreter.h

@@ -142,6 +142,11 @@ namespace cling {
     ///
     InvocationOptions m_Opts;
 
+    ///\brief Storage to hold parenting information, which is also used as a
+    /// a fixed address/location passed to the JIT's linker for gCling.
+    ///
+    Interpreter** m_Parenting;
+
     ///\brief The llvm library state, a per-thread object.
     ///
     std::unique_ptr<llvm::LLVMContext> m_LLVMContext;
@@ -332,6 +337,14 @@ namespace cling {
     ///
     bool isValid() const;
 
+    ///\brief Returns this interpreter's parent or null: while (P = parent())
+    ///
+    Interpreter* parent();
+
+    ///\brief Returns greatest ancestor of this interpreter. Might be itself.
+    ///
+    Interpreter& ancestor();
+
     const InvocationOptions& getOptions() const { return m_Opts; }
     InvocationOptions& getOptions() { return m_Opts; }
 

include/cling/Interpreter/RuntimeUniverse.h

@@ -21,7 +21,11 @@
 #define __STDC_CONSTANT_MACROS // needed by System/DataTypes.h
 #endif
 
-#ifdef __cplusplus
+#ifndef __cplusplus
+
+extern const void* const gCling;
+
+#else
 
 #include <new>
 
@@ -36,7 +40,7 @@ namespace cling {
     /// \brief The interpreter provides itself as a builtin, i.e. it
     /// interprets itself. This is particularly important for implementing
     /// the dynamic scopes and the runtime bindings
-    extern Interpreter* gCling;
+    extern Interpreter* const gCling;
 
     namespace internal {
       /// \brief Some of clang's routines rely on valid source locations and
@@ -177,15 +181,20 @@ namespace cling {
 using namespace cling::runtime;
 
 extern "C" {
-  ///\brief a function that throws InvalidDerefException. This allows to 'hide'
-  /// the definition of the exceptions from the RuntimeUniverse and allows us to
-  /// run cling in -no-rtti mode.
-  ///
-
-  void* cling_runtime_internal_throwIfInvalidPointer(void* Sema,
-                                                    void* Expr,
-                                                    const void* Arg);
-}
+
 #endif // __cplusplus
 
+///\brief a function that throws InvalidDerefException. This allows to 'hide'
+/// the definition of the exceptions from the RuntimeUniverse and allows us to
+/// run cling in -no-rtti mode.
+///
+
+void* cling_runtime_internal_throwIfInvalidPointer(void* Sema,
+                                                   void* Expr,
+                                                   const void* Arg);
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
 #endif // CLING_RUNTIME_UNIVERSE_H

include/cling/Utils/AST.h

@@ -50,14 +50,37 @@ namespace utils {
     ///
     bool IsWrapper(const clang::FunctionDecl* ND);
 
+    ///\brief Get the mangled name of a NamedDecl.
+    ///
+    ///\param [in]  ND - Try to mangle this decl's name.
+    ///\param [in]  GD - Provide the GlobalDecl if what is to be mangled is a
+    /// constructor or destructor.
+    ///
+    ///\returns The mangled or pure name (when ND should not be mangled) on
+    /// success or an empty string on failure.
+    ///
+    std::string maybeMangleDeclName(const clang::NamedDecl* ND,
+                                    const clang::GlobalDecl* GD = nullptr);
+
     ///\brief Get the mangled name of a GlobalDecl.
     ///
-    ///\param [in]  GD - try to mangle this decl's name.
-    ///\param [out] mangledName - put the mangled name in here.
+    ///\param [in]  GD - Try to mangle this decl's name.
     ///
-    void maybeMangleDeclName(const clang::GlobalDecl& GD,
-                             std::string& mangledName);
+    ///\returns The mangled or pure name (when ND should not be mangled) on
+    /// success or an empty string on failure.
+    ///
+    std::string maybeMangleDeclName(const clang::GlobalDecl& GD);
 
+    ///\brief Get the mangled name of a clang::Decl subclass. FunctionDecl,
+    /// VarDecl, ValueDecl, and NamedDecl are currently supported.
+    ///
+    ///\param [in]  Decl - Try to mangle this decl's name.
+    ///
+    ///\returns The mangled or pure name (when ND should not be mangled) on
+    /// success or an empty string on failure.
+    ///
+    template <typename T>
+    std::string maybeMangleDeclName(const T* Decl);
 
     ///\brief Retrieves the last expression of a function body. If it was a
     /// DeclStmt with a variable declaration, creates DeclRefExpr and adds it to

lib/Interpreter/DeclUnloader.cpp

@@ -853,17 +853,16 @@ bool DeclUnloader::VisitRedeclarable(clang::Redeclarable<T>* R, DeclContext* DC)
         utils::DiagnosticsOverride IgnoreMangleErrors(m_Sema->getDiagnostics());
 #endif
 #endif
-        utils::Analyze::maybeMangleDeclName(GD, mangledName);
+        utils::Analyze::maybeMangleDeclName(GD).swap(mangledName);
       }
 
       // Handle static locals. void func() { static int var; } is represented
       // in the llvm::Module is a global named @func.var
       if (const VarDecl* VD = dyn_cast<VarDecl>(GD.getDecl())) {
         if (VD->isStaticLocal()) {
-          std::string functionMangledName;
-          GlobalDecl FDGD(cast<FunctionDecl>(VD->getDeclContext()));
-          utils::Analyze::maybeMangleDeclName(FDGD, functionMangledName);
-          mangledName = functionMangledName + "." + mangledName;
+          mangledName = utils::Analyze::maybeMangleDeclName(GlobalDecl(
+                            cast<FunctionDecl>(VD->getDeclContext()))) +
+                        "." + mangledName;
         }
       }
 

lib/Interpreter/IncrementalExecutor.cpp

@@ -317,7 +317,7 @@ IncrementalExecutor::installLazyFunctionCreator(LazyFunctionCreatorFunc_t fp)
 }
 
 bool
-IncrementalExecutor::addSymbol(const char* Name,  void* Addr,
+IncrementalExecutor::addSymbol(llvm::StringRef Name,  void* Addr,
                                bool Jit) {
   return m_JIT->lookupSymbol(Name, Addr, Jit).second;
 }

lib/Interpreter/IncrementalExecutor.h

@@ -209,7 +209,7 @@ namespace cling {
     /// @param[in] JIT - Add to the JIT injected symbol table
     /// @returns true if the symbol is successfully registered, false otherwise.
     ///
-    bool addSymbol(const char* Name, void* Address, bool JIT = false);
+    bool addSymbol(llvm::StringRef Name, void* Address, bool JIT = false);
 
     ///\brief Add a llvm::Module to the JIT.
     ///

lib/Interpreter/Interpreter.cpp

@@ -185,12 +185,19 @@ namespace cling {
   Interpreter::Interpreter(int argc, const char* const *argv,
                            const char* llvmdir /*= 0*/, bool noRuntime,
                            const Interpreter* parentInterp) :
-    m_Opts(argc, argv),
+    m_Opts(argc, argv), m_Parenting(nullptr),
     m_UniqueCounter(parentInterp ? parentInterp->m_UniqueCounter + 1 : 0),
     m_PrintDebug(false), m_DynamicLookupDeclared(false),
     m_DynamicLookupEnabled(false), m_RawInputEnabled(false),
     m_OptLevel(parentInterp ? parentInterp->m_OptLevel : -1) {
 
+     if (parentInterp) {
+       m_Parenting = new Interpreter*[2];
+       m_Parenting[0] = this;
+       m_Parenting[1] = const_cast<Interpreter*>(parentInterp);
+     } else
+       m_Parenting = reinterpret_cast<Interpreter**>(this);
+
     if (handleSimpleOptions(m_Opts))
       return;
 
@@ -222,9 +229,12 @@ namespace cling {
         return;
     }
 
+    const CompilerInstance* CI = getCI();
+    const LangOptions& LangOpts = CI->getLangOpts();
+
     // Tell the diagnostic client that we are entering file parsing mode.
-    DiagnosticConsumer& DClient = getCI()->getDiagnosticClient();
-    DClient.BeginSourceFile(getCI()->getLangOpts(), &PP);
+    DiagnosticConsumer& DClient = CI->getDiagnosticClient();
+    DClient.BeginSourceFile(LangOpts, &PP);
 
     llvm::SmallVector<IncrementalParser::ParseResultTransaction, 2>
       IncrParserTransactions;
@@ -259,12 +269,40 @@ namespace cling {
   #endif
             if (GV) {
               if (void* Addr = m_Executor->getPointerToGlobalFromJIT(*GV))
-                m_Executor->addSymbol(Sym.str().c_str(), Addr, true);
+                m_Executor->addSymbol(Sym, Addr, true);
               else
                 cling::errs() << Sym << " not defined\n";
             } else
               cling::errs() << Sym << " not in Module!\n";
           }
+
+          const clang::Decl* Scope =
+              LangOpts.CPlusPlus
+                  ? m_LookupHelper->findScope("cling::runtime",
+                                              LookupHelper::NoDiagnostics)
+                  : CI->getSema().getASTContext().getTranslationUnitDecl();
+          if (!Scope) {
+            cling::errs() << "Scope for gCling was not found\n";
+          } else if (const clang::ValueDecl* gCling =
+                         m_LookupHelper->findDataMember(
+                             Scope, "gCling", LookupHelper::NoDiagnostics)) {
+            std::string Name = !LangOpts.CPlusPlus ? "gCling" :
+                                    utils::Analyze::maybeMangleDeclName(gCling);
+            if (!Name.empty()) {
+#ifdef LLVM_ON_WIN32
+              // MS mangling is purposely adding a prefix of '\x1'...why?
+              if (Name[0] == '\x1')
+                Name.erase(0, 1);
+#endif
+              // gCling gets linked to top-most Interpreter.
+              if (!parent())
+                m_Executor->addSymbol(Name, &m_Parenting, true);
+              else
+                m_Executor->addSymbol(Name, &m_Parenting[1], true);
+            }
+          } else {
+            cling::errs() << "gCling was not found\n";
+          }
         }
       }
     }
@@ -340,6 +378,21 @@ namespace cling {
     // explicitly, before the implicit destruction (through the unique_ptr) of
     // the callbacks.
     m_IncrParser.reset(0);
+
+    if (m_Parenting != reinterpret_cast<Interpreter**>(this))
+      delete [] m_Parenting;
+  }
+
+  Interpreter* Interpreter::parent() {
+    if (m_Parenting == reinterpret_cast<Interpreter**>(this))
+      return nullptr;
+    return m_Parenting[1];
+  }
+
+  Interpreter& Interpreter::ancestor() {
+    if (m_Parenting == reinterpret_cast<Interpreter**>(this))
+      return *this;
+    return m_Parenting[1]->ancestor();
   }
 
   Transaction* Interpreter::Initialize(bool NoRuntime, bool SyntaxOnly,
@@ -356,26 +409,13 @@ namespace cling {
     // (on OS X at least, so probably Linux too) and the JIT thinks the symbol
     // is undefined in a child Interpreter.  And speaking of children, should
     // gCling actually be thisCling, so a child Interpreter can only access
-    // itself? One could use a macro (simillar to __dso_handle) to block
-    // assignemnt and get around the mangling issue.
-    const char* Linkage = LangOpts.CPlusPlus ? "extern \"C\"" : "";
-    if (!NoRuntime) {
-      if (LangOpts.CPlusPlus) {
-        Strm << "#include \"cling/Interpreter/RuntimeUniverse.h\"\n";
-        if (EmitDefinitions)
-          Strm << "namespace cling { class Interpreter; namespace runtime { "
-                  "Interpreter* gCling=(Interpreter*)" << ThisP << ";}}\n";
-      } else {
-        Strm << "#include \"cling/Interpreter/CValuePrinter.h\"\n"
-             << "void* gCling";
-        if (EmitDefinitions)
-          Strm << "=(void*)" << ThisP;
-        Strm << ";\n";
-      }
-    }
+    // itself?
+    if (!NoRuntime)
+      Strm << "#include \"cling/Interpreter/RuntimeUniverse.h\"\n";
 
     // Intercept all atexit calls, as the Interpreter and functions will be long
     // gone when the -native- versions invoke them.
+    const char* Linkage = LangOpts.CPlusPlus ? "extern \"C\"" : "";
 #if defined(__GLIBCXX__) && !defined(__APPLE__)
     const char* LinkageCxx = "extern \"C++\"";
     const char* Attr = LangOpts.CPlusPlus ? " throw () " : "";
@@ -943,10 +983,8 @@ namespace cling {
     if (!FD)
       return kExeUnkownFunction;
 
-    std::string mangledNameIfNeeded;
-    utils::Analyze::maybeMangleDeclName(FD, mangledNameIfNeeded);
     IncrementalExecutor::ExecutionResult ExeRes =
-       m_Executor->executeWrapper(mangledNameIfNeeded, res);
+       m_Executor->executeWrapper(utils::Analyze::maybeMangleDeclName(FD), res);
     return ConvertExecutionResult(ExeRes);
   }
 
@@ -1510,9 +1548,7 @@ namespace cling {
   void* Interpreter::getAddressOfGlobal(const GlobalDecl& GD,
                                         bool* fromJIT /*=0*/) const {
     // Return a symbol's address, and whether it was jitted.
-    std::string mangledName;
-    utils::Analyze::maybeMangleDeclName(GD, mangledName);
-    return getAddressOfGlobal(mangledName, fromJIT);
+    return getAddressOfGlobal(utils::Analyze::maybeMangleDeclName(GD), fromJIT);
   }
 
   void* Interpreter::getAddressOfGlobal(llvm::StringRef SymName,