--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/include/llvm/ExecutionEngine/Orc/IndirectionUtils.h	Wed Feb 18 14:55:36 2015 +0900
@@ -0,0 +1,244 @@
+//===-- IndirectionUtils.h - Utilities for adding indirections --*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Contains utilities for adding indirections and breaking up modules.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_EXECUTIONENGINE_ORC_INDIRECTIONUTILS_H
+#define LLVM_EXECUTIONENGINE_ORC_INDIRECTIONUTILS_H
+
+#include "JITSymbol.h"
+#include "llvm/ADT/DenseSet.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/Mangler.h"
+#include "llvm/IR/Module.h"
+#include <sstream>
+
+namespace llvm {
+
+/// @brief Base class for JITLayer independent aspects of
+///        JITCompileCallbackManager.
+template <typename TargetT>
+class JITCompileCallbackManagerBase {
+public:
+
+  /// @brief Construct a JITCompileCallbackManagerBase.
+  /// @param ErrorHandlerAddress The address of an error handler in the target
+  ///                            process to be used if a compile callback fails.
+  /// @param NumTrampolinesPerBlock Number of trampolines to emit if there is no
+  ///                             available trampoline when getCompileCallback is
+  ///                             called.
+  JITCompileCallbackManagerBase(TargetAddress ErrorHandlerAddress,
+                                unsigned NumTrampolinesPerBlock)
+    : ErrorHandlerAddress(ErrorHandlerAddress),
+      NumTrampolinesPerBlock(NumTrampolinesPerBlock) {}
+
+  /// @brief Execute the callback for the given trampoline id. Called by the JIT
+  ///        to compile functions on demand.
+  TargetAddress executeCompileCallback(TargetAddress TrampolineID) {
+    typename TrampolineMapT::iterator I = ActiveTrampolines.find(TrampolineID);
+    // FIXME: Also raise an error in the Orc error-handler when we finally have
+    //        one.
+    if (I == ActiveTrampolines.end())
+      return ErrorHandlerAddress;
+
+    // Found a callback handler. Yank this trampoline out of the active list and
+    // put it back in the available trampolines list, then try to run the
+    // handler's compile and update actions.
+    // Moving the trampoline ID back to the available list first means there's at
+    // least one available trampoline if the compile action triggers a request for
+    // a new one.
+    AvailableTrampolines.push_back(I->first);
+    auto CallbackHandler = std::move(I->second);
+    ActiveTrampolines.erase(I);
+
+    if (auto Addr = CallbackHandler.Compile()) {
+      CallbackHandler.Update(Addr);
+      return Addr;
+    }
+    return ErrorHandlerAddress;
+  }
+
+protected:
+
+  typedef std::function<TargetAddress()> CompileFtorT;
+  typedef std::function<void(TargetAddress)> UpdateFtorT;
+
+  struct CallbackHandler {
+    CompileFtorT Compile;
+    UpdateFtorT Update;
+  };
+
+  TargetAddress ErrorHandlerAddress;
+  unsigned NumTrampolinesPerBlock;
+
+  typedef std::map<TargetAddress, CallbackHandler> TrampolineMapT;
+  TrampolineMapT ActiveTrampolines;
+  std::vector<TargetAddress> AvailableTrampolines;
+};
+
+/// @brief Manage compile callbacks.
+template <typename JITLayerT, typename TargetT>
+class JITCompileCallbackManager :
+    public JITCompileCallbackManagerBase<TargetT> {
+public:
+
+  typedef typename JITCompileCallbackManagerBase<TargetT>::CompileFtorT
+    CompileFtorT;
+  typedef typename JITCompileCallbackManagerBase<TargetT>::UpdateFtorT
+    UpdateFtorT;
+
+  /// @brief Construct a JITCompileCallbackManager.
+  /// @param JIT JIT layer to emit callback trampolines, etc. into.
+  /// @param Context LLVMContext to use for trampoline & resolve block modules.
+  /// @param ErrorHandlerAddress The address of an error handler in the target
+  ///                            process to be used if a compile callback fails.
+  /// @param NumTrampolinesPerBlock Number of trampolines to allocate whenever
+  ///                               there is no existing callback trampoline.
+  ///                               (Trampolines are allocated in blocks for
+  ///                               efficiency.)
+  JITCompileCallbackManager(JITLayerT &JIT, LLVMContext &Context,
+                            TargetAddress ErrorHandlerAddress,
+                            unsigned NumTrampolinesPerBlock)
+    : JITCompileCallbackManagerBase<TargetT>(ErrorHandlerAddress,
+                                             NumTrampolinesPerBlock),
+      JIT(JIT) {
+    emitResolverBlock(Context);
+  }
+
+  /// @brief Handle to a newly created compile callback. Can be used to get an
+  ///        IR constant representing the address of the trampoline, and to set
+  ///        the compile and update actions for the callback.
+  class CompileCallbackInfo {
+  public:
+    CompileCallbackInfo(Constant *Addr, CompileFtorT &Compile,
+                        UpdateFtorT &Update)
+      : Addr(Addr), Compile(Compile), Update(Update) {}
+
+    Constant* getAddress() const { return Addr; }
+    void setCompileAction(CompileFtorT Compile) {
+      this->Compile = std::move(Compile);
+    }
+    void setUpdateAction(UpdateFtorT Update) {
+      this->Update = std::move(Update);
+    }
+  private:
+    Constant *Addr;
+    CompileFtorT &Compile;
+    UpdateFtorT &Update;
+  };
+
+  /// @brief Get/create a compile callback with the given signature.
+  CompileCallbackInfo getCompileCallback(FunctionType &FT) {
+    TargetAddress TrampolineAddr = getAvailableTrampolineAddr(FT.getContext());
+    auto &CallbackHandler =
+      this->ActiveTrampolines[TrampolineAddr + TargetT::CallSize];
+    Constant *AddrIntVal =
+      ConstantInt::get(Type::getInt64Ty(FT.getContext()), TrampolineAddr);
+    Constant *AddrPtrVal =
+      ConstantExpr::getCast(Instruction::IntToPtr, AddrIntVal,
+                            PointerType::get(&FT, 0));
+
+    return CompileCallbackInfo(AddrPtrVal, CallbackHandler.Compile,
+                               CallbackHandler.Update);
+  }
+
+  /// @brief Get a functor for updating the value of a named function pointer.
+  UpdateFtorT getLocalFPUpdater(typename JITLayerT::ModuleSetHandleT H,
+                                std::string Name) {
+    // FIXME: Move-capture Name once we can use C++14.
+    return [=](TargetAddress Addr) {
+      auto FPSym = JIT.findSymbolIn(H, Name, true);
+      assert(FPSym && "Cannot find function pointer to update.");
+      void *FPAddr = reinterpret_cast<void*>(
+                       static_cast<uintptr_t>(FPSym.getAddress()));
+      memcpy(FPAddr, &Addr, sizeof(uintptr_t));
+    };
+  }
+
+private:
+
+  std::vector<std::unique_ptr<Module>>
+  SingletonSet(std::unique_ptr<Module> M) {
+    std::vector<std::unique_ptr<Module>> Ms;
+    Ms.push_back(std::move(M));
+    return Ms;
+  }
+
+  void emitResolverBlock(LLVMContext &Context) {
+    std::unique_ptr<Module> M(new Module("resolver_block_module",
+                                         Context));
+    TargetT::insertResolverBlock(*M, *this);
+    auto H = JIT.addModuleSet(SingletonSet(std::move(M)), nullptr);
+    JIT.emitAndFinalize(H);
+    auto ResolverBlockSymbol =
+      JIT.findSymbolIn(H, TargetT::ResolverBlockName, false);
+    assert(ResolverBlockSymbol && "Failed to insert resolver block");
+    ResolverBlockAddr = ResolverBlockSymbol.getAddress();
+  }
+
+  TargetAddress getAvailableTrampolineAddr(LLVMContext &Context) {
+    if (this->AvailableTrampolines.empty())
+      grow(Context);
+    assert(!this->AvailableTrampolines.empty() &&
+           "Failed to grow available trampolines.");
+    TargetAddress TrampolineAddr = this->AvailableTrampolines.back();
+    this->AvailableTrampolines.pop_back();
+    return TrampolineAddr;
+  }
+
+  void grow(LLVMContext &Context) {
+    assert(this->AvailableTrampolines.empty() && "Growing prematurely?");
+    std::unique_ptr<Module> M(new Module("trampoline_block", Context));
+    auto GetLabelName =
+      TargetT::insertCompileCallbackTrampolines(*M, ResolverBlockAddr,
+                                                this->NumTrampolinesPerBlock,
+                                                this->ActiveTrampolines.size());
+    auto H = JIT.addModuleSet(SingletonSet(std::move(M)), nullptr);
+    JIT.emitAndFinalize(H);
+    for (unsigned I = 0; I < this->NumTrampolinesPerBlock; ++I) {
+      std::string Name = GetLabelName(I);
+      auto TrampolineSymbol = JIT.findSymbolIn(H, Name, false);
+      assert(TrampolineSymbol && "Failed to emit trampoline.");
+      this->AvailableTrampolines.push_back(TrampolineSymbol.getAddress());
+    }
+  }
+
+  JITLayerT &JIT;
+  TargetAddress ResolverBlockAddr;
+};
+
+GlobalVariable* createImplPointer(Function &F, const Twine &Name,
+                                  Constant *Initializer);
+
+void makeStub(Function &F, GlobalVariable &ImplPointer);
+
+typedef std::map<Module*, DenseSet<const GlobalValue*>> ModulePartitionMap;
+
+void partition(Module &M, const ModulePartitionMap &PMap);
+
+/// @brief Struct for trivial "complete" partitioning of a module.
+class FullyPartitionedModule {
+public:
+  std::unique_ptr<Module> GlobalVars;
+  std::unique_ptr<Module> Commons;
+  std::vector<std::unique_ptr<Module>> Functions;
+
+  FullyPartitionedModule() = default;
+  FullyPartitionedModule(FullyPartitionedModule &&S)
+      : GlobalVars(std::move(S.GlobalVars)), Commons(std::move(S.Commons)),
+        Functions(std::move(S.Functions)) {}
+};
+
+FullyPartitionedModule fullyPartition(Module &M);
+
+}
+
+#endif // LLVM_EXECUTIONENGINE_ORC_INDIRECTIONUTILS_H