Enable CppInterOp

.github/workflows/cppinterop-diff.yml

@@ -0,0 +1,26 @@
+name: Diff CppInterOp against upstream
+on:
+  pull_request:
+    paths:
+      - 'interpreter/CppInterOp/**'
+
+jobs:
+  cppinterop-diff:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out ROOT
+        uses: actions/checkout@v4
+        with:
+          path: root
+      - name: Check out CppInterOp
+        uses: actions/checkout@v4
+        with:
+          repository: compiler-research/CppInterOp
+          ref: 6c6f94a22bd971520a249e2c02e4259cdd3a5be6
+          path: CppInterOp
+      - name: Drop directories that are not added to ROOT
+        working-directory: CppInterOp
+        run: |
+          rm -rf .git .github discord.svg
+      - name: Compare
+        run: diff -ur CppInterOp/ root/interpreter/CppInterOp/

core/metacling/src/CMakeLists.txt

@@ -44,6 +44,7 @@ target_include_directories(MetaCling SYSTEM PRIVATE
   ${CLANG_INCLUDE_DIRS}
   ${LLVM_INCLUDE_DIRS}
   ${CLAD_INCLUDE_DIRS}
+  ${CPPINTEROP_INCLUDE_DIRS}
 )
 
 target_include_directories(MetaCling PRIVATE
@@ -74,7 +75,7 @@ if(MSVC)
    set_source_files_properties(TCling.cxx COMPILE_FLAGS /bigobj)
 endif()
 
-add_dependencies(MetaCling CLING)
+add_dependencies(MetaCling CLING clangCppInterOp)
 
 ##### libCling #############################################################
 
@@ -113,11 +114,15 @@ ROOT_LINKER_LIBRARY(Cling
         $<TARGET_OBJECTS:ClingUtils>
         $<TARGET_OBJECTS:Dictgen>
         $<TARGET_OBJECTS:MetaCling>
-        LIBRARIES ${CLING_LIBRARIES} ${LINK_LIBS} ${CLING_PLUGIN_LINK_LIBS})
+        LIBRARIES ${CLING_LIBRARIES} clangCppInterOp ${LINK_LIBS} ${CLING_PLUGIN_LINK_LIBS})
 
 # When these two link at the same time, they can exhaust the RAM on many machines, since they both link against llvm.
 add_dependencies(Cling rootcling_stage1)
 
+if(testing)
+  add_dependencies(Cling CppInterOpUnitTests)
+endif()
+
 if(MSVC)
   set_target_properties(Cling PROPERTIES WINDOWS_EXPORT_ALL_SYMBOLS TRUE)
   set(cling_exports ${cling_exports}

core/metacling/src/TCling.cxx

@@ -115,6 +115,8 @@ clang/LLVM technology.
 #include "cling/Utils/SourceNormalization.h"
 #include "cling/Interpreter/Exception.h"
 
+#include "clang/Interpreter/CppInterOp.h"
+
 #include "llvm/IR/GlobalValue.h"
 #include "llvm/IR/Module.h"
 
@@ -1539,6 +1541,11 @@ TCling::TCling(const char *name, const char *title, const char* const argv[], vo
    if (!fInterpreter->getCI()) { // Compiler instance could not be created. See https://its.cern.ch/jira/browse/ROOT-10239
       return;
    }
+
+   // Tell CppInterOp that the cling::Interpreter instance is managed externally by ROOT
+   // Sets the interpreter by passing the fInterpreter handle as soon as TCling is initialized
+   Cpp::UseExternalInterpreter((Cpp::TInterp_t*)fInterpreter.get());
+
    // Don't check whether modules' files exist.
    fInterpreter->getCI()->getPreprocessorOpts().DisablePCHOrModuleValidation =
       DisableValidationForModuleKind::All;

interpreter/CMakeLists.txt

@@ -514,3 +514,15 @@ mark_as_advanced(FORCE BUG_REPORT_URL BUILD_CLANG_FORMAT_VS_PLUGIN BUILD_SHARED_
                        C_INCLUDE_DIRS DEFAULT_SYSROOT FFI_INCLUDE_DIR FFI_LIBRARY_DIR
                        GCC_INSTALL_PREFIX LIBCLANG_BUILD_STATIC TOOL_INFO_PLIST)
 mark_as_advanced(CLEAR LLVM_ENABLE_ASSERTIONS LLVM_BUILD_TYPE)
+
+##################### LIBINTEROP ###########################
+
+#---Set InterOp include directories, for any ROOT component that requires the headers--------------------------------------------------------
+set(CPPINTEROP_INCLUDE_DIRS
+  ${CMAKE_CURRENT_SOURCE_DIR}/CppInterOp/include
+  CACHE STRING "CppInterOp include directories.")
+
+#---Set InterOp to build on Cling, this can be toggled to use Clang-REPL-------------------------------------------------------
+set(CPPINTEROP_USE_CLING ON BOOL "Use Cling as backend")
+
+add_subdirectory(CppInterOp)

interpreter/CppInterOp/.clang-format

@@ -0,0 +1,17 @@
+BasedOnStyle: LLVM
+
+Language: Cpp
+Standard: Cpp11
+PointerAlignment: Left
+
+IncludeCategories:
+  - Regex:           '^"[^/]+\"'
+    Priority:        10
+  - Regex:           '^"cling/'
+    Priority:        20
+  - Regex:           '^"clang/'
+    Priority:        30
+  - Regex:           '^"llvm/'
+    Priority:        40
+  - Regex:           '^<'
+    Priority:        50

interpreter/CppInterOp/.clang-tidy

@@ -0,0 +1,60 @@
+Checks: >
+  -*,
+  bugprone-*,
+  clang-diagnostic-*,
+  clang-analyzer-*,
+  cppcoreguidelines-*,
+  llvm-*,
+  misc-*,
+  modernize-*,
+  performance-*,
+  portability-*,
+  readability-*,
+  -bugprone-narrowing-conversions,
+  -bugprone-easily-swappable-parameters,
+  -bugprone-implicit-widening-of-multiplication-result,
+  -bugprone-unchecked-optional-access,
+  -misc-const-correctness,
+  -misc-unused-parameters,
+  -misc-non-private-member-variables-in-classes,
+  -misc-no-recursion,
+  -misc-use-anonymous-namespace,
+  -modernize-return-braced-init-list,
+  -modernize-use-trailing-return-type,
+  -readability-braces-around-statements,
+  -readability-identifier-length,
+  -readability-implicit-bool-conversion,
+  -readability-magic-numbers,
+  -readability-named-parameter,
+  -readability-function-cognitive-complexity,
+  -readability-redundant-access-specifiers,
+  -cppcoreguidelines-avoid-magic-numbers,
+  -cppcoreguidelines-init-variables,
+  -cppcoreguidelines-pro-bounds-pointer-arithmetic,
+  -cppcoreguidelines-pro-type-member-init,
+  -cppcoreguidelines-macro-usage,
+  -llvm-namespace-comment
+
+CheckOptions:
+  - key:             readability-identifier-naming.ClassCase
+    value:           aNy_CasE
+  - key:             readability-identifier-naming.FunctionCase
+    value:           aNy_CasE
+  - key:             readability-identifier-naming.MemberCase
+    value:           aNy_CasE
+  - key:             readability-identifier-naming.ParameterCase
+    value:           aNy_CasE
+  - key:             readability-identifier-naming.UnionCase
+    value:           CamelCase
+  - key:             readability-identifier-naming.VariableCase
+    value:           aNy_CasE
+  - key:             readability-identifier-naming.IgnoreMainLikeFunctions
+    value:           1
+  - key:             cppcoreguidelines-avoid-magic-numbers.IgnoreMacros
+    value:           1
+  - key:             cppcoreguidelines-pro-bounds-pointer-arithmetic.Pessimistic
+    value:           1
+  - key:             cppcoreguidelines-pro-type-member-init.InitWithEquals
+    value:           1
+  - key:             llvm-namespace-comment.Spaces
+    value:           2

interpreter/CppInterOp/.codecov.yml

@@ -0,0 +1,25 @@
+codecov:
+  require_ci_to_pass: no
+
+coverage:
+  precision: 2
+  round: down
+  range: "70...100"
+
+  status:
+    project: yes
+    patch: yes
+    changes: no
+
+parsers:
+  gcov:
+    branch_detection:
+      conditional: yes
+      loop: yes
+      method: no
+      macro: no
+
+comment:
+  layout: "reach, diff, flags, tree, files"
+  behavior: default
+  require_changes: no

interpreter/CppInterOp/.gitignore

@@ -0,0 +1,41 @@
+# Prerequisites
+*.d
+
+# Compiled Object files
+*.slo
+*.lo
+*.o
+*.obj
+
+# Precompiled Headers
+*.gch
+*.pch
+
+# Compiled Dynamic libraries
+*.so
+*.dylib
+*.dll
+
+# Compiled Static libraries
+*.lai
+*.la
+*.a
+*.lib
+
+# Executables
+*.exe
+*.out
+*.app
+
+# Directories
+build
+install
+
+# CLion files
+.idea
+
+# VSCode files
+.vscode
+
+# Default Virtual Environments
+.venv

interpreter/CppInterOp/.readthedocs.yaml

@@ -0,0 +1,16 @@
+version: 2
+
+sphinx:
+  configuration: docs/conf.py
+  builder: html
+
+build:
+  os: "ubuntu-22.04"
+  tools:
+    python: "3.11"
+  apt_packages:
+    - clang-13
+    - cmake
+    - libclang-13-dev
+    - llvm-13-dev
+    - llvm-13-tools