WIP: Prototype #ifdef-enforced DEPENDS on tablegen output

[jroelofs]

link back to the discourse thread: https://discourse.llvm.org/t/rfc-permanently-fixing-the-missing-tablegen-dependency-issue/70442/14?u=jroelofs

clang/include/clang/Driver/CMakeLists.txt

 set(LLVM_TARGET_DEFINITIONS Options.td)
-tablegen(LLVM Options.inc -gen-opt-parser-defs)
+tablegen(LLVM Options.inc -gen-opt-parser-defs -dependency-guard=ClangDriverOptions)
 add_public_tablegen_target(ClangDriverOptions)

clang/lib/ARCMigrate/CMakeLists.txt

add_clang_library(clangARCMigrate
   clangFrontend
   clangLex
   clangRewrite
   clangSema
   clangSerialization
 
   DEPENDS
   omp_gen
+  ClangDriverOptions
   )

clang/lib/Analysis/plugins/CheckerDependencyHandling/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   Support
   )
 
 set(LLVM_EXPORTED_SYMBOL_FILE ${CMAKE_CURRENT_SOURCE_DIR}/CheckerDependencyHandlingAnalyzerPlugin.exports)
-add_llvm_library(CheckerDependencyHandlingAnalyzerPlugin MODULE BUILDTREE_ONLY CheckerDependencyHandling.cpp)
+add_llvm_library(
+  CheckerDependencyHandlingAnalyzerPlugin
+
+  MODULE
+  BUILDTREE_ONLY
+
+  CheckerDependencyHandling.cpp
+
+  DEPENDS
+  ClangDriverOptions)
 
 clang_target_link_libraries(CheckerDependencyHandlingAnalyzerPlugin PRIVATE
   clangAnalysis
   clangAST
   clangStaticAnalyzerCore
   clangStaticAnalyzerFrontend
   )

clang/lib/Analysis/plugins/CheckerOptionHandling/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   Support
   )
 
 set(LLVM_EXPORTED_SYMBOL_FILE ${CMAKE_CURRENT_SOURCE_DIR}/CheckerOptionHandlingAnalyzerPlugin.exports)
-add_llvm_library(CheckerOptionHandlingAnalyzerPlugin MODULE BUILDTREE_ONLY CheckerOptionHandling.cpp)
+add_llvm_library(
+  CheckerOptionHandlingAnalyzerPlugin
+
+  MODULE
+  BUILDTREE_ONLY
+
+  CheckerOptionHandling.cpp
+
+  DEPENDS
+  ClangDriverOptions)
 
 clang_target_link_libraries(CheckerOptionHandlingAnalyzerPlugin PRIVATE
   clangAnalysis
   clangAST
   clangStaticAnalyzerCore
   clangStaticAnalyzerFrontend
   )

clang/lib/Analysis/plugins/SampleAnalyzer/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   Support
   )
 
 set(LLVM_EXPORTED_SYMBOL_FILE ${CMAKE_CURRENT_SOURCE_DIR}/SampleAnalyzerPlugin.exports)
-add_llvm_library(SampleAnalyzerPlugin MODULE BUILDTREE_ONLY MainCallChecker.cpp)
+add_llvm_library(
+  SampleAnalyzerPlugin
+
+  MODULE
+  BUILDTREE_ONLY
+
+  MainCallChecker.cpp
+
+  DEPENDS
+  ClangDriverOptions)
 
 clang_target_link_libraries(SampleAnalyzerPlugin PRIVATE
   clangAnalysis
   clangAST
   clangStaticAnalyzerCore
   clangStaticAnalyzerFrontend
   )

clang/lib/CodeGen/CMakeLists.txt

add_clang_library(clangCodeGen
   PatternInit.cpp
   SanitizerMetadata.cpp
   SwiftCallingConv.cpp
   TargetInfo.cpp
   VarBypassDetector.cpp
 
   DEPENDS
   intrinsics_gen
+  ClangDriverOptions
 
   LINK_LIBS
   clangAST
   clangAnalysis
   clangBasic
   clangFrontend
   clangLex
   clangSerialization
   )

clang/lib/CrossTU/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   Support
   TargetParser
   )
 
 add_clang_library(clangCrossTU
   CrossTranslationUnit.cpp
 
   LINK_LIBS
   clangAST
   clangBasic
   clangFrontend
   clangIndex
+
+  DEPENDS
+  ClangDriverOptions
   )

clang/lib/Driver/CMakeLists.txt

add_clang_library(clangDriver
   XRayArgs.cpp
 
   DEPENDS
   ClangDriverOptions
 
   LINK_LIBS
   clangBasic
   ${system_libs}
-  )
+  )
 No newline at end of file

clang/lib/ExtractAPI/CMakeLists.txt

add_clang_library(clangExtractAPI
   TypedefUnderlyingTypeResolver.cpp
 
   LINK_LIBS
   clangAST
   clangBasic
   clangFrontend
   clangIndex
   clangLex
+
+  DEPENDS
+  ClangDriverOptions
   )

clang/lib/Frontend/Rewrite/CMakeLists.txt

add_clang_library(clangRewriteFrontend
   clangEdit
   clangFrontend
   clangLex
   clangRewrite
   clangSerialization
 
   DEPENDS
   omp_gen
+  ClangDriverOptions
   )

clang/lib/Index/CMakeLists.txt

add_clang_library(clangIndex
   clangFormat
   clangFrontend
   clangLex
   clangSerialization
   clangToolingCore
 
   DEPENDS
   omp_gen
+  ClangDriverOptions
   )

clang/lib/StaticAnalyzer/Core/CMakeLists.txt

add_clang_library(clangStaticAnalyzerCore
   clangCrossTU
   clangFrontend
   clangLex
   clangRewrite
   clangToolingCore
 
   DEPENDS
   omp_gen
+  ClangDriverOptions
   )
 

clang/lib/StaticAnalyzer/Frontend/CMakeLists.txt

add_clang_library(clangStaticAnalyzerFrontend
   clangCrossTU
   clangFrontend
   clangLex
   clangStaticAnalyzerCheckers
   clangStaticAnalyzerCore
 
   DEPENDS
   omp_gen
+  ClangDriverOptions
   )

clang/lib/Tooling/ASTDiff/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   Support
   )
 
 add_clang_library(clangToolingASTDiff
   ASTDiff.cpp
   LINK_LIBS
   clangBasic
   clangAST
   clangLex
 
   DEPENDS
   omp_gen
+  ClangDriverOptions
   )

clang/lib/Tooling/DumpTool/CMakeLists.txt

 
 add_clang_executable(clang-ast-dump
   ASTSrcLocProcessor.cpp
   ClangSrcLocDump.cpp
+
+  DEPENDS
+  ClangDriverOptions
 )
 
 target_link_libraries(clang-ast-dump
   PRIVATE
   clangAST
   clangASTMatchers
   clangBasic
   clangDriver
   clangFrontend
   clangSerialization
   clangToolingCore
 )

clang/lib/Tooling/Refactoring/CMakeLists.txt

add_clang_library(clangToolingRefactoring
   clangFormat
   clangIndex
   clangLex
   clangRewrite
   clangToolingCore
 
   DEPENDS
   omp_gen
+  ClangDriverOptions
   )

clang/lib/Tooling/Syntax/CMakeLists.txt

add_clang_library(clangToolingSyntax
   clangAST
   clangBasic
   clangFrontend
   clangLex
   clangToolingCore
 
   DEPENDS
   omp_gen
+  ClangDriverOptions
   )

clang/lib/Tooling/Transformer/CMakeLists.txt

add_clang_library(clangTransformer
   clangASTMatchers
   clangBasic
   clangLex
   clangToolingCore
   clangToolingRefactoring
 
   DEPENDS
   omp_gen
+  ClangDriverOptions
   )

clang/tools/arcmt-test/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   support
   )
 
 add_clang_executable(arcmt-test
   arcmt-test.cpp
+
+  DEPENDS
+  ClangDriverOptions
   )
 
 clang_target_link_libraries(arcmt-test
   PRIVATE
   clangARCMigrate
   clangBasic
   clangFrontend
   clangLex
   clangSerialization
   )

clang/tools/c-index-test/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   support
 )
 
 add_clang_executable(c-index-test
   c-index-test.c
   core_main.cpp
+
+  DEPENDS
+  ClangDriverOptions
   )
 
 if(NOT MSVC)
   set_property(
     SOURCE c-index-test.c
     PROPERTY COMPILE_FLAGS "-std=gnu89"
     )
 endif()

clang/tools/clang-check/CMakeLists.txt

 set( LLVM_LINK_COMPONENTS
   ${LLVM_TARGETS_TO_BUILD}
   Option
   Support
   )
 
 add_clang_tool(clang-check
   ClangCheck.cpp
+
+  DEPENDS
+  ClangDriverOptions
   )
 
 clang_target_link_libraries(clang-check
   PRIVATE
   clangAST
   clangBasic
   clangDriver
   clangFrontend
   clangRewriteFrontend
   clangSerialization
   clangStaticAnalyzerFrontend
   clangTooling
   clangToolingSyntax
   )

clang/tools/clang-diff/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   Support
   )
 
 add_clang_executable(clang-diff
   ClangDiff.cpp
+
+  DEPENDS
+  ClangDriverOptions
   )
 
 clang_target_link_libraries(clang-diff
   PRIVATE
   clangBasic
   clangFrontend
   clangSerialization
   clangTooling
   clangToolingASTDiff
   )

clang/tools/clang-extdef-mapping/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   ${LLVM_TARGETS_TO_BUILD}
   support
   )
 
 add_clang_tool(clang-extdef-mapping
   ClangExtDefMapGen.cpp
+  DEPENDS
+  ClangDriverOptions
   )
 
 clang_target_link_libraries(clang-extdef-mapping
   PRIVATE
   clangAST
   clangBasic
   clangCrossTU
   clangFrontend
   clangSerialization
   clangTooling
   )

clang/tools/clang-fuzzer/handle-cxx/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS ${LLVM_TARGETS_TO_BUILD} Support)
 
 add_clang_library(clangHandleCXX
   handle_cxx.cpp
 
   LINK_LIBS
   clangBasic
   clangCodeGen
   clangFrontend
   clangLex
   clangSerialization
   clangTooling
+
+  DEPENDS
+  ClangDriverOptions
   )
 
 target_include_directories(clangHandleCXX PRIVATE .)

clang/tools/clang-import-test/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   Core
   Support
   TargetParser
   )
 
 add_clang_executable(clang-import-test
   clang-import-test.cpp
   DEPENDS
   intrinsics_gen
+  ClangDriverOptions
   )
 
 set(CLANG_IMPORT_TEST_LIB_DEPS
   clangAST
   clangBasic
   clangCodeGen
   clangDriver
   clangFrontend

clang/tools/clang-offload-bundler/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   Object
   Support
   TargetParser
   )
 
 add_clang_tool(clang-offload-bundler
   ClangOffloadBundler.cpp
 
   DEPENDS
   intrinsics_gen
+  ClangDriverOptions
   )
 
 set(CLANG_OFFLOAD_BUNDLER_LIB_DEPS
   clangBasic
   clangDriver
   )
 
 clang_target_link_libraries(clang-offload-bundler
   PRIVATE
   ${CLANG_OFFLOAD_BUNDLER_LIB_DEPS}
   )

clang/tools/clang-refactor/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   Option
   Support
   )
 
 add_clang_tool(clang-refactor
   ClangRefactor.cpp
   TestSupport.cpp
+
+  DEPENDS
+  ClangDriverOptions
   )
 
 clang_target_link_libraries(clang-refactor
   PRIVATE
   clangAST
   clangBasic
   clangFormat
   clangFrontend
   clangLex
   clangRewrite
   clangSerialization
   clangTooling
   clangToolingCore
   clangToolingRefactoring
   )

clang/tools/clang-rename/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   Option
   Support
   )
 
 add_clang_tool(clang-rename
   ClangRename.cpp
+
+  DEPENDS
+  ClangDriverOptions
   )
 
 clang_target_link_libraries(clang-rename
   PRIVATE
   clangBasic
   clangFrontend
   clangRewrite
   clangSerialization

clang/tools/clang-repl/CMakeLists.txt

 set( LLVM_LINK_COMPONENTS
   ${LLVM_TARGETS_TO_BUILD}
   Core
   LineEditor
   Option
   OrcJIT
   Support
   )
 
 add_clang_tool(clang-repl
   ClangRepl.cpp
+  DEPENDS
+  ClangDriverOptions
   )
 
 clang_target_link_libraries(clang-repl PRIVATE
   clangBasic
   clangFrontend
   clangInterpreter
   )
 
 # Support plugins.
 if(CLANG_PLUGIN_SUPPORT)
   export_executable_symbols_for_plugins(clang-repl)
 endif()

clang/tools/clang-scan-deps/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   Core
   Option
   Support
   TargetParser
   )
 
 set(LLVM_TARGET_DEFINITIONS Opts.td)
 tablegen(LLVM Opts.inc -gen-opt-parser-defs)
 add_public_tablegen_target(ScanDepsOptsTableGen)
 
 add_clang_tool(clang-scan-deps
   ClangScanDeps.cpp
 
   DEPENDS
+  ClangDriverOptions
   ScanDepsOptsTableGen
   GENERATE_DRIVER
   )
 
 set(CLANG_SCAN_DEPS_LIB_DEPS
   clangAST
   clangBasic
   clangDependencyScanning

clang/tools/diagtool/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   Support
   )
 
 add_clang_tool(diagtool
   diagtool_main.cpp
   DiagTool.cpp
   DiagnosticNames.cpp
   FindDiagnosticID.cpp
   ListWarnings.cpp
   ShowEnabledWarnings.cpp
   TreeView.cpp
+
+  DEPENDS
+  ClangDriverOptions
 )
 
 clang_target_link_libraries(diagtool
   PRIVATE
   clangBasic
   clangFrontend
   )

clang/tools/driver/CMakeLists.txt

 add_clang_tool(clang
   driver.cpp
   cc1_main.cpp
   cc1as_main.cpp
   cc1gen_reproducer_main.cpp
 
   DEPENDS
   intrinsics_gen
+  ClangDriverOptions
   ${support_plugins}
   GENERATE_DRIVER
   )
 
 clang_target_link_libraries(clang
   PRIVATE
   clangBasic
   clangCodeGen

llvm/cmake/modules/AddLLVM.cmake

if((ARG_SHARED AND ARG_STATIC) OR ARG_OBJECT)
     # Do add_dependencies(obj) later due to CMake issue 14747.
     list(APPEND objlibs ${obj_name})
 
     # Bring in the target include directories from our original target.
     target_include_directories(${obj_name} PRIVATE $<TARGET_PROPERTY:${name},INCLUDE_DIRECTORIES>)
 
     set_target_properties(${obj_name} PROPERTIES FOLDER "Object Libraries")
     if(ARG_DEPENDS)
+      foreach(dependency ${ARG_DEPENDS})
+        string(REPLACE "-" "_" dependency ${dependency})
+        target_compile_definitions(${obj_name} PUBLIC -DLLVM_DEPENDS_ON_${dependency}=1)
+      endforeach()
       add_dependencies(${obj_name} ${ARG_DEPENDS})
     endif()
     # Treat link libraries like PUBLIC dependencies.  LINK_LIBS might
     # result in generating header files.  Add a dependendency so that
     # the generated header is created before this object library.
     if(ARG_LINK_LIBS)
       cmake_parse_arguments(LINK_LIBS_ARG
         ""
function(llvm_add_library name)
   endif()
 
   if(ARG_SHARED AND ARG_STATIC)
     # static
     set(name_static "${name}_static")
     if(ARG_OUTPUT_NAME)
       set(output_name OUTPUT_NAME "${ARG_OUTPUT_NAME}")
     endif()
+    if(ARG_DEPENDS)
+      foreach(dependency ${ARG_DEPENDS})
+        string(REPLACE "-" "_" dependency ${dependency})
+        target_compile_definitions(${name_static} PRIVATE -DLLVM_DEPENDS_ON_${dependency}=1)
+      endforeach()
+    endif()
     # DEPENDS has been appended to LLVM_COMMON_LIBS.
     llvm_add_library(${name_static} STATIC
       ${output_name}
       OBJLIBS ${ALL_FILES} # objlib
       LINK_LIBS ${ARG_LINK_LIBS}
       LINK_COMPONENTS ${ARG_LINK_COMPONENTS}
       )
 
if(ARG_MODULE)
     add_library(${name} MODULE ${ALL_FILES})
   elseif(ARG_SHARED)
     add_windows_version_resource_file(ALL_FILES ${ALL_FILES})
     add_library(${name} SHARED ${ALL_FILES})
   else()
     add_library(${name} STATIC ${ALL_FILES})
   endif()
 
+  if(ARG_DEPENDS)
+    foreach(dependency ${ARG_DEPENDS})
+      string(REPLACE "-" "_" dependency ${dependency})
+      target_compile_definitions(${name} PRIVATE -DLLVM_DEPENDS_ON_${dependency}=1)
+    endforeach()
+  endif()
+
   if(ARG_COMPONENT_LIB)
     set_target_properties(${name} PROPERTIES LLVM_COMPONENT TRUE)
     set_property(GLOBAL APPEND PROPERTY LLVM_COMPONENT_LIBS ${name})
   endif()
 
   if(NOT ARG_NO_INSTALL_RPATH)
     if(ARG_MODULE OR ARG_SHARED)
       llvm_setup_rpath(${name})
if (ARG_GENERATE_DRIVER)
     endif()
   endif()
 endmacro()
 
 macro(add_llvm_executable name)
   cmake_parse_arguments(ARG
     "DISABLE_LLVM_LINK_LLVM_DYLIB;IGNORE_EXTERNALIZE_DEBUGINFO;NO_INSTALL_RPATH;SUPPORT_PLUGINS"
     "ENTITLEMENTS;BUNDLE_PATH"
-    ""
+    "DEPENDS"
     ${ARGN})
-  generate_llvm_objects(${name} ${ARG_UNPARSED_ARGUMENTS})
+  generate_llvm_objects(${name} ${ARG_UNPARSED_ARGUMENTS} DEPENDS ${ARG_DEPENDS})
   add_windows_version_resource_file(ALL_FILES ${ALL_FILES})
 
   if(XCODE)
     # Note: the dummy.cpp source file provides no definitions. However,
     # it forces Xcode to properly link the static library.
     list(APPEND ALL_FILES "${LLVM_MAIN_SRC_DIR}/cmake/dummy.cpp")
   endif()
 
   if( EXCLUDE_FROM_ALL )
     add_executable(${name} EXCLUDE_FROM_ALL ${ALL_FILES})
   else()
     add_executable(${name} ${ALL_FILES})
   endif()
 
+  foreach(dependency ${ARG_DEPENDS})
+    string(REPLACE "-" "_" dependency ${dependency})
+    target_compile_definitions(${name} PRIVATE -DLLVM_DEPENDS_ON_${dependency}=1)
+  endforeach()
+
   setup_dependency_debugging(${name} ${LLVM_COMMON_DEPENDS})
 
   if(NOT ARG_NO_INSTALL_RPATH)
     llvm_setup_rpath(${name})
   elseif(NOT "${LLVM_LOCAL_RPATH}" STREQUAL "")
     # Enable BUILD_WITH_INSTALL_RPATH unless CMAKE_BUILD_RPATH is set.
     if("${CMAKE_BUILD_RPATH}" STREQUAL "")
       set_property(TARGET ${name} PROPERTY BUILD_WITH_INSTALL_RPATH ON)

llvm/lib/TableGen/Main.cpp

static int createDependencyFile(const TGParser &Parser, const char *argv0) {
   for (const auto &Dep : Parser.getDependencies()) {
     DepOut.os() << ' ' << Dep;
   }
   DepOut.os() << "\n";
   DepOut.keep();
   return 0;
 }
 
+static cl::opt<std::string>
+DependencyGuardName("dependency-guard=", cl::Prefix, cl::Hidden, cl::init(""));
+
+static void EmitDependencyGuard(StringRef Name, raw_ostream &OS) {
+  OS << "#ifndef LLVM_DEPENDS_ON_" << Name << "\n"
+     << "#  error If you're seeing this message, there is a missing DEPENDS "
+     << Name << " in the CMake target that includes this file.\n"
+     << "#endif\n";
+}
+
 int llvm::TableGenMain(const char *argv0,
                        std::function<TableGenMainFn> MainFn) {
   RecordKeeper Records;
 
   if (TimePhases)
     Records.startPhaseTiming();
 
   // Parse the input file.
int llvm::TableGenMain(const char *argv0,
   unsigned status = 0;
   TableGen::Emitter::FnT ActionFn = TableGen::Emitter::Action->getValue();
   if (ActionFn)
     ActionFn(Records, Out);
   else if (MainFn)
     status = MainFn(Out, Records);
   else
     return 1;
+  if (!DependencyGuardName.empty()) {
+    EmitDependencyGuard(DependencyGuardName, Out);
+  }
   Records.stopBackendTimer();
   if (status)
     return 1;
 
   // Always write the depfile, even if the main output hasn't changed.
   // If it's missing, Ninja considers the output dirty.  If this was below
   // the early exit below and someone deleted the .inc.d file but not the .inc
   // file, tablegen would never write the depfile.