[Documentation Improvement]: Patch made for different LLVM version

[codegallivant]

Description of issue with documention/Way documentation can be improved

In the README, it asks to apply the OOP JIT patch in the following manner-

git clone --depth=1 --branch release/21.x https://github.com/llvm/llvm-project.git
cd llvm-project
git apply -v ../CppInterOp/patches/llvm/clang20-1-out-of-process.patch

However, if you try running the patch, it will return an error, because the patch is not made for release/21.x. I have verified this on an Ubuntu 24.04 x86 container.
Output (for release/21.x)-

llvm-project  release/21.x  git apply -v ../CppInterOp/patches/llvm/clang20-1-out-of-process.patch                                                                   ✔  18:18:27

Checking patch clang/include/clang/Interpreter/Interpreter.h...
error: while searching for:

#include "llvm/ADT/DenseMap.h"
#include "llvm/ExecutionEngine/JITSymbol.h"
#include "llvm/ExecutionEngine/Orc/Shared/ExecutorAddress.h"
#include "llvm/Support/Error.h"
#include <memory>
#include <vector>


error: patch failed: clang/include/clang/Interpreter/Interpreter.h:20
error: clang/include/clang/Interpreter/Interpreter.h: patch does not apply
Checking patch clang/lib/Interpreter/IncrementalExecutor.cpp...
Checking patch clang/lib/Interpreter/IncrementalExecutor.h...
Checking patch clang/lib/Interpreter/Interpreter.cpp...
error: while searching for:
#include "clang/Sema/Lookup.h"
#include "clang/Serialization/ObjectFilePCHContainerReader.h"
#include "llvm/ExecutionEngine/JITSymbol.h"
#include "llvm/ExecutionEngine/Orc/LLJIT.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/Errc.h"

error: patch failed: clang/lib/Interpreter/Interpreter.cpp:46
error: clang/lib/Interpreter/Interpreter.cpp: patch does not apply
Checking patch clang/tools/clang-repl/ClangRepl.cpp...
error: while searching for:
//===----------------------------------------------------------------------===//

#include "clang/Basic/Diagnostic.h"
#include "clang/Frontend/CompilerInstance.h"
#include "clang/Frontend/FrontendDiagnostic.h"
#include "clang/Interpreter/CodeCompletion.h"

error: patch failed: clang/tools/clang-repl/ClangRepl.cpp:11
error: clang/tools/clang-repl/ClangRepl.cpp: patch does not apply
Checking patch llvm/lib/ExecutionEngine/Orc/LLJIT.cpp...
error: while searching for:
      int32_t result;
      auto E = ES.callSPSWrapper<SPSDLUpdateSig>(WrapperAddr->getAddress(),
                                                 result, DSOHandles[&JD]);
      if (result)
        return make_error<StringError>("dlupdate failed",
                                       inconvertibleErrorCode());
      return E;
    }
    return ES.callSPSWrapper<SPSDLOpenSig>(WrapperAddr->getAddress(),
                                           DSOHandles[&JD], JD.getName(),
                                           int32_t(ORC_RT_RTLD_LAZY));
  } else
    return WrapperAddr.takeError();
}

Error ORCPlatformSupport::deinitialize(orc::JITDylib &JD) {

error: patch failed: llvm/lib/ExecutionEngine/Orc/LLJIT.cpp:635
error: llvm/lib/ExecutionEngine/Orc/LLJIT.cpp: patch does not apply

The patch works with release/20.x.

[codegallivant]

Is the correct way to fix this to create a new patch for 21.x or to alter the documentation to use 20.x ?

[mcbarton]

We do not have an official oop patch for llvm 21. I have one locally that will apply to llvm 21, but is untested and there is no plans to upstream this patch. Once we have llvm 22 support, we plan to drop the llvm 20 oop patch.