feature: introduce clang frontend to detect illegal usage of C++ proteus functions

.gitlab-ci.yml

@@ -30,7 +30,7 @@ variables:
 ##### LC GITLAB CONFIGURATION
 # Keep Proteus clones out of the default ~/.jacamar-ci/builds, which other
 # projects' CI jobs share and clean up.
-  CUSTOM_CI_BUILDS_DIR: "/usr/workspace/fink12/gitlab-runner-proteus"
+  CUSTOM_CI_BUILDS_DIR: "/usr/workspace/proteus-dev/gitlab-runner"
 # Tells Gitlab to recursively update the submodules when cloning the project.
 #  GIT_SUBMODULE_STRATEGY: recursive
 

cmake/ProteusFunctions.cmake

@@ -9,13 +9,17 @@ function(add_proteus target)
             "-fplugin=$<TARGET_FILE:ProteusPass>"
             "-fpass-plugin=$<TARGET_FILE:ProteusPass>"
             "SHELL:-Xclang -mllvm -Xclang -force-proteus-jit-annotate-all"
+            "-fplugin=\$<TARGET_FILE:ProteusASTChecker>"
         )
     else()
         target_compile_options(${target} PRIVATE
             "-fpass-plugin=\$<TARGET_FILE:ProteusPass>"
+            "-fplugin=\$<TARGET_FILE:ProteusASTChecker>"
         )
     endif()
 
+    add_dependencies(${target} ProteusPass ProteusASTChecker)
+
     target_link_options(${target} PRIVATE
         "SHELL:\$<\$<LINK_LANGUAGE:HIP>:-Xoffload-linker --load-pass-plugin=\$<TARGET_FILE:ProteusPassOffload>>")
 

docs/user/integration.md

@@ -36,15 +36,18 @@ linking flags, for example:
 
 ```bash
 CXXFLAGS += -I<install_path>/include \
+    -fplugin=<install_path>/<libdir>/libProteusASTChecker.so \
     -fpass-plugin=<install_path>/<libdir>/libProteusPass.so
 
 LDFLAGS += -L<install_path>/<libdir> \
     -Wl,-rpath,<install_path>/<libdir> \
     -lproteus $(llvm-config --libs) -lclang-cpp
 ```
 
-If you don't use code annotations, you can omit the `-fpass-plugin` option,
-since the LLVM pass is only needed for processing annotations.
+The frontend checker loaded by `-fplugin` diagnoses unsupported uses of
+`proteus::register_lambda` and `proteus::jit_variable` before LLVM IR is
+emitted. If you don't use code annotations or these lambda APIs, you can omit
+both plugin options.
 
 !!! note
     The example above is the simplest case and is closest to a host-only build.

src/pass/CMakeLists.txt

@@ -48,6 +48,18 @@ add_library(ProteusPassOffload SHARED
   $<TARGET_OBJECTS:ProteusPassObjects>
 )
 
+# Keep the Clang frontend plugin separate from the LLVM pass plugin: the pass
+# is also loaded by opt/offload linkers, which do not provide Clang symbols.
+add_library(ProteusASTChecker SHARED LambdaASTChecker.cpp)
+target_include_directories(ProteusASTChecker SYSTEM PRIVATE
+  ${LLVM_INCLUDE_DIRS}
+  ${CLANG_INCLUDE_DIRS})
+if(NOT LLVM_ENABLE_RTTI)
+  target_compile_options(ProteusASTChecker PRIVATE -fno-rtti)
+endif()
+target_link_options(ProteusASTChecker
+  PRIVATE "$<$<PLATFORM_ID:Darwin>:LINKER:SHELL:-undefined dynamic_lookup>")
+
 # Allow undefined symbols in shared objects on Darwin (this is the default
 # behaviour on Linux)
 target_link_options(ProteusPass
@@ -72,7 +84,7 @@ target_link_options(
   "SHELL:$<$<LINK_LANGUAGE:HIP>:-Xoffload-linker --load-pass-plugin=$<TARGET_FILE:ProteusPassOffload>>"
 )
 
-set_target_properties(ProteusPass ProteusPassOffload PROPERTIES
+set_target_properties(ProteusPass ProteusPassOffload ProteusASTChecker PROPERTIES
   # on macOS enable passing RPATH flags to the linker; no-ops on Linux
   MACOSX_RPATH          ON
   # let CMake use INSTALL_RPATH even in the build tree
@@ -85,7 +97,7 @@ set_target_properties(ProteusPass ProteusPassOffload PROPERTIES
 # is ready to support Clang/LLVM pass consumers too.
 if(NOT PROTEUS_PYTHON_WHEEL)
   install(
-    TARGETS ProteusPass ProteusPassOffload
+    TARGETS ProteusPass ProteusPassOffload ProteusASTChecker
     EXPORT proteusTargets
     RUNTIME DESTINATION "${CMAKE_INSTALL_LIBDIR}"
     LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}"