[clang] [clang-repl] Add support for running custom code in Remote JIT executor (PR #157358)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Abhinav Kumar (kr-2003)

<details>
<summary>Changes</summary>

Introduce a custom lambda mechanism that allows injecting user-defined code into the Remote JIT’s executor.

---
Full diff: https://github.com/llvm/llvm-project/pull/157358.diff


4 Files Affected:

- (modified) clang/include/clang/Interpreter/Interpreter.h (+3-1) 
- (modified) clang/lib/Interpreter/IncrementalExecutor.cpp (+5-1) 
- (modified) clang/lib/Interpreter/IncrementalExecutor.h (+2-1) 
- (modified) clang/lib/Interpreter/Interpreter.cpp (+2-1) 


``````````diff
diff --git a/clang/include/clang/Interpreter/Interpreter.h b/clang/include/clang/Interpreter/Interpreter.h
index 61af7bf762d5e..54be57684c03f 100644
--- a/clang/include/clang/Interpreter/Interpreter.h
+++ b/clang/include/clang/Interpreter/Interpreter.h
@@ -135,11 +135,13 @@ class Interpreter {
     std::string OrcRuntimePath = "";
     /// PID of the out-of-process JIT executor.
     uint32_t ExecutorPID = 0;
+    /// Custom lambda to be executed inside child process/executor
+    std::function<void()> CustomizeFork = nullptr;
 
     JITConfig()
         : IsOutOfProcess(false), OOPExecutor(""), OOPExecutorConnect(""),
           UseSharedMemory(false), SlabAllocateSize(0), OrcRuntimePath(""),
-          ExecutorPID(0) {}
+          ExecutorPID(0), CustomizeFork(nullptr) {}
   };
 
 protected:
diff --git a/clang/lib/Interpreter/IncrementalExecutor.cpp b/clang/lib/Interpreter/IncrementalExecutor.cpp
index b0eb7d0e9f072..792ecb08c5f33 100644
--- a/clang/lib/Interpreter/IncrementalExecutor.cpp
+++ b/clang/lib/Interpreter/IncrementalExecutor.cpp
@@ -138,7 +138,8 @@ IncrementalExecutor::getSymbolAddress(llvm::StringRef Name,
 
 Expected<std::unique_ptr<llvm::jitlink::JITLinkMemoryManager>>
 createSharedMemoryManager(llvm::orc::SimpleRemoteEPC &SREPC,
-                          unsigned SlabAllocateSize) {
+                          unsigned SlabAllocateSize,
+                          std::function<void()> CustomizeFork) {
   llvm::orc::SharedMemoryMapper::SymbolAddrs SAs;
   if (auto Err = SREPC.getBootstrapSymbols(
           {{SAs.Instance,
@@ -215,6 +216,9 @@ IncrementalExecutor::launchExecutor(llvm::StringRef ExecutablePath,
     close(ToExecutor[WriteEnd]);
     close(FromExecutor[ReadEnd]);
 
+    if (CustomizeFork)
+      CustomizeFork();
+
     // Execute the child process.
     std::unique_ptr<char[]> ExecutorPath, FDSpecifier;
     {
diff --git a/clang/lib/Interpreter/IncrementalExecutor.h b/clang/lib/Interpreter/IncrementalExecutor.h
index d091535166770..bb1ec33452515 100644
--- a/clang/lib/Interpreter/IncrementalExecutor.h
+++ b/clang/lib/Interpreter/IncrementalExecutor.h
@@ -79,7 +79,8 @@ class IncrementalExecutor {
   static llvm::Expected<
       std::pair<std::unique_ptr<llvm::orc::SimpleRemoteEPC>, uint32_t>>
   launchExecutor(llvm::StringRef ExecutablePath, bool UseSharedMemory,
-                 unsigned SlabAllocateSize);
+                 unsigned SlabAllocateSize,
+                 std::function<void()> CustomizeFork = nullptr);
 
 #if LLVM_ON_UNIX && LLVM_ENABLE_THREADS
   static llvm::Expected<std::unique_ptr<llvm::orc::SimpleRemoteEPC>>
diff --git a/clang/lib/Interpreter/Interpreter.cpp b/clang/lib/Interpreter/Interpreter.cpp
index 043e0c1e5754e..2425a628b59b9 100644
--- a/clang/lib/Interpreter/Interpreter.cpp
+++ b/clang/lib/Interpreter/Interpreter.cpp
@@ -355,7 +355,8 @@ Interpreter::outOfProcessJITBuilder(JITConfig Config) {
   if (!Config.OOPExecutor.empty()) {
     // Launch an out-of-process executor locally in a child process.
     auto ResultOrErr = IncrementalExecutor::launchExecutor(
-        Config.OOPExecutor, Config.UseSharedMemory, Config.SlabAllocateSize);
+        Config.OOPExecutor, Config.UseSharedMemory, Config.SlabAllocateSize,
+        Config.CustomizeFork);
     if (!ResultOrErr)
       return ResultOrErr.takeError();
     childPid = ResultOrErr->second;

``````````

</details>


https://github.com/llvm/llvm-project/pull/157358