[Clang-Repl] Add support for out-of-process execution. (llvm#110418)

This PR introduces out-of-process (OOP) execution support for
Clang-Repl. With this enhancement, two new flags, `oop-executor` and
`oop-executor-connect`, are added to the Clang-Repl interface. These
flags enable the launch of an external executor
(`llvm-jitlink-executor`), which handles code execution in a separate
process.

Author: SahilPatidar

clang/include/clang/Interpreter/Interpreter.h

@@ -20,6 +20,7 @@
 
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ExecutionEngine/JITSymbol.h"
+#include "llvm/ExecutionEngine/Orc/ExecutorProcessControl.h"
 #include "llvm/ExecutionEngine/Orc/Shared/ExecutorAddress.h"
 #include "llvm/Support/Error.h"
 #include <memory>
@@ -129,10 +130,14 @@ class Interpreter {
 public:
   virtual ~Interpreter();
   static llvm::Expected<std::unique_ptr<Interpreter>>
-  create(std::unique_ptr<CompilerInstance> CI);
+  create(std::unique_ptr<CompilerInstance> CI,
+         std::unique_ptr<llvm::orc::LLJITBuilder> JITBuilder = nullptr);
   static llvm::Expected<std::unique_ptr<Interpreter>>
   createWithCUDA(std::unique_ptr<CompilerInstance> CI,
                  std::unique_ptr<CompilerInstance> DCI);
+  static llvm::Expected<std::unique_ptr<llvm::orc::LLJITBuilder>>
+  createLLJITBuilder(std::unique_ptr<llvm::orc::ExecutorProcessControl> EPC,
+                     llvm::StringRef OrcRuntimePath);
   const ASTContext &getASTContext() const;
   ASTContext &getASTContext();
   const CompilerInstance *getCompilerInstance() const;

clang/include/clang/Interpreter/RemoteJITUtils.h

@@ -0,0 +1,38 @@
+//===-- RemoteJITUtils.h - Utilities for remote-JITing ----------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Utilities for ExecutorProcessControl-based remote JITing with Orc and
+// JITLink.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_INTERPRETER_REMOTEJITUTILS_H
+#define LLVM_CLANG_INTERPRETER_REMOTEJITUTILS_H
+
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ExecutionEngine/Orc/Core.h"
+#include "llvm/ExecutionEngine/Orc/Layer.h"
+#include "llvm/ExecutionEngine/Orc/SimpleRemoteEPC.h"
+#include "llvm/Support/Error.h"
+
+#include <cstdint>
+#include <memory>
+#include <string>
+
+llvm::Expected<std::unique_ptr<llvm::orc::SimpleRemoteEPC>>
+launchExecutor(llvm::StringRef ExecutablePath, bool UseSharedMemory,
+               llvm::StringRef SlabAllocateSizeString);
+
+/// Create a JITLinkExecutor that connects to the given network address
+/// through a TCP socket. A valid NetworkAddress provides hostname and port,
+/// e.g. localhost:20000.
+llvm::Expected<std::unique_ptr<llvm::orc::SimpleRemoteEPC>>
+connectTCPSocket(llvm::StringRef NetworkAddress, bool UseSharedMemory,
+                 llvm::StringRef SlabAllocateSizeString);
+
+#endif // LLVM_CLANG_INTERPRETER_REMOTEJITUTILS_H

clang/lib/Interpreter/CMakeLists.txt

@@ -25,6 +25,7 @@ add_clang_library(clangInterpreter
   Interpreter.cpp
   InterpreterValuePrinter.cpp
   InterpreterUtils.cpp
+  RemoteJITUtils.cpp
   Value.cpp
   ${WASM_SRC}
   PARTIAL_SOURCES_INTENDED

clang/lib/Interpreter/Interpreter.cpp

@@ -44,6 +44,7 @@
 #include "clang/Sema/Lookup.h"
 #include "clang/Serialization/ObjectFilePCHContainerReader.h"
 #include "llvm/ExecutionEngine/JITSymbol.h"
+#include "llvm/ExecutionEngine/Orc/EPCDynamicLibrarySearchGenerator.h"
 #include "llvm/ExecutionEngine/Orc/LLJIT.h"
 #include "llvm/IR/Module.h"
 #include "llvm/Support/Errc.h"
@@ -456,10 +457,11 @@ const char *const Runtimes = R"(
 )";
 
 llvm::Expected<std::unique_ptr<Interpreter>>
-Interpreter::create(std::unique_ptr<CompilerInstance> CI) {
+Interpreter::create(std::unique_ptr<CompilerInstance> CI,
+                    std::unique_ptr<llvm::orc::LLJITBuilder> JB) {
   llvm::Error Err = llvm::Error::success();
-  auto Interp =
-      std::unique_ptr<Interpreter>(new Interpreter(std::move(CI), Err));
+  auto Interp = std::unique_ptr<Interpreter>(
+      new Interpreter(std::move(CI), Err, JB ? std::move(JB) : nullptr));
   if (Err)
     return std::move(Err);
 
@@ -578,6 +580,25 @@ createJITTargetMachineBuilder(const std::string &TT) {
   return llvm::orc::JITTargetMachineBuilder(llvm::Triple(TT));
 }
 
+llvm::Expected<std::unique_ptr<llvm::orc::LLJITBuilder>>
+Interpreter::createLLJITBuilder(
+    std::unique_ptr<llvm::orc::ExecutorProcessControl> EPC,
+    llvm::StringRef OrcRuntimePath) {
+  const std::string &TT = EPC->getTargetTriple().getTriple();
+  auto JTMB = createJITTargetMachineBuilder(TT);
+  if (!JTMB)
+    return JTMB.takeError();
+  auto JB = IncrementalExecutor::createDefaultJITBuilder(std::move(*JTMB));
+  if (!JB)
+    return JB.takeError();
+
+  (*JB)->setExecutorProcessControl(std::move(EPC));
+  (*JB)->setPlatformSetUp(
+      llvm::orc::ExecutorNativePlatform(OrcRuntimePath.str()));
+
+  return std::move(*JB);
+}
+
 llvm::Error Interpreter::CreateExecutor() {
   if (IncrExecutor)
     return llvm::make_error<llvm::StringError>("Operation failed. "
@@ -702,11 +723,11 @@ llvm::Error Interpreter::LoadDynamicLibrary(const char *name) {
   if (!EE)
     return EE.takeError();
 
-  auto &DL = EE->getDataLayout();
-
-  if (auto DLSG = llvm::orc::DynamicLibrarySearchGenerator::Load(
-          name, DL.getGlobalPrefix()))
-    EE->getMainJITDylib().addGenerator(std::move(*DLSG));
+  if (auto DLSG = llvm::orc::EPCDynamicLibrarySearchGenerator::Load(
+          EE->getExecutionSession(), name))
+    // FIXME: Eventually we should put each library in its own JITDylib and
+    //        turn off process symbols by default.
+    EE->getProcessSymbolsJITDylib()->addGenerator(std::move(*DLSG));
   else
     return DLSG.takeError();