[Clang][Docs] Fix man page build

This patch fixes the man page build. It currently doesn't work as
SOURCE_DIR isn't set correctly (just undefined) within the
add_sphinx_target function. This patch also moves around the creation of
targets for autogenerated rst files so that both the man page and html
build can depend upon them as before only the html build depended on
them.

Fixes #62540

Reviewed By: tstellar

Differential Revision: https://reviews.llvm.org/D149809

Author: boomanaiden154

clang/docs/CMakeLists.txt

@@ -90,50 +90,60 @@ if (LLVM_ENABLE_DOXYGEN)
 endif()
 endif()
 
-function (gen_rst_file_from_td output_file td_option source docs_target)
+function (gen_rst_file_from_td output_file td_option source docs_targets)
   if (NOT EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/${source}")
     message(FATAL_ERROR "Cannot find source file: ${source} in ${CMAKE_CURRENT_SOURCE_DIR}")
   endif()
   get_filename_component(TABLEGEN_INCLUDE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/${source}" DIRECTORY)
   list(APPEND LLVM_TABLEGEN_FLAGS "-I${TABLEGEN_INCLUDE_DIR}")
   clang_tablegen(${output_file} ${td_option} SOURCE ${source} TARGET "gen-${output_file}")
-  add_dependencies(${docs_target} "gen-${output_file}")
+  foreach(target ${docs_targets})
+    add_dependencies(${target} gen-${output_file})
+  endforeach()
 endfunction()
 
 if (LLVM_ENABLE_SPHINX)
   include(AddSphinxTarget)
-  if (SPHINX_FOUND)
+  if (SPHINX_FOUND AND (${SPHINX_OUTPUT_HTML} OR ${SPHINX_OUTPUT_MAN}))
+    # Copy rst files to build directory before generating the html
+    # documentation.  Some of the rst files are generated, so they
+    # only exist in the build directory.  Sphinx needs all files in
+    # the same directory in order to generate the html, so we need to
+    # copy all the non-gnerated rst files from the source to the build
+    # directory before we run sphinx.
+    add_custom_target(copy-clang-rst-docs
+      COMMAND "${CMAKE_COMMAND}" -E copy_directory
+      "${CMAKE_CURRENT_SOURCE_DIR}" "${CMAKE_CURRENT_BINARY_DIR}"
+
+      COMMAND "${CMAKE_COMMAND}" -E copy_if_different
+      "${CMAKE_CURRENT_SOURCE_DIR}/../CodeOwners.rst"
+      "${CMAKE_CURRENT_BINARY_DIR}"
+    )
+
+    set(docs_targets "")
+
     if (${SPHINX_OUTPUT_HTML})
       add_sphinx_target(html clang SOURCE_DIR "${CMAKE_CURRENT_BINARY_DIR}")
 
-      # Copy rst files to build directory before generating the html
-      # documentation.  Some of the rst files are generated, so they
-      # only exist in the build directory.  Sphinx needs all files in
-      # the same directory in order to generate the html, so we need to
-      # copy all the non-gnerated rst files from the source to the build
-      # directory before we run sphinx.
-      add_custom_target(copy-clang-rst-docs
-        COMMAND "${CMAKE_COMMAND}" -E copy_directory
-        "${CMAKE_CURRENT_SOURCE_DIR}" "${CMAKE_CURRENT_BINARY_DIR}"
-
-        COMMAND "${CMAKE_COMMAND}" -E copy_if_different
-        "${CMAKE_CURRENT_SOURCE_DIR}/../CodeOwners.rst"
-        "${CMAKE_CURRENT_BINARY_DIR}"
-      )
-      add_dependencies(docs-clang-html copy-clang-rst-docs)
-
       add_custom_command(TARGET docs-clang-html POST_BUILD
         COMMAND "${CMAKE_COMMAND}" -E copy
         "${CMAKE_CURRENT_SOURCE_DIR}/LibASTMatchersReference.html"
         "${CMAKE_CURRENT_BINARY_DIR}/html/LibASTMatchersReference.html")
 
-      # Generated files
-      gen_rst_file_from_td(AttributeReference.rst -gen-attr-docs ../include/clang/Basic/Attr.td docs-clang-html)
-      gen_rst_file_from_td(DiagnosticsReference.rst -gen-diag-docs ../include/clang/Basic/Diagnostic.td docs-clang-html)
-      gen_rst_file_from_td(ClangCommandLineReference.rst -gen-opt-docs ../include/clang/Driver/ClangOptionDocs.td docs-clang-html)
+      list(APPEND docs_targets "docs-clang-html")
     endif()
     if (${SPHINX_OUTPUT_MAN})
-      add_sphinx_target(man clang)
+      add_sphinx_target(man clang SOURCE_DIR "${CMAKE_CURRENT_BINARY_DIR}")
+      list(APPEND docs_targets "docs-clang-man")
     endif()
+
+    # Generated files
+    gen_rst_file_from_td(AttributeReference.rst -gen-attr-docs ../include/clang/Basic/Attr.td "${docs_targets}")
+    gen_rst_file_from_td(DiagnosticsReference.rst -gen-diag-docs ../include/clang/Basic/Diagnostic.td "${docs_targets}")
+    gen_rst_file_from_td(ClangCommandLineReference.rst -gen-opt-docs ../include/clang/Driver/ClangOptionDocs.td "${docs_targets}")
+
+    foreach(target ${docs_targets})
+      add_dependencies(${target} copy-clang-rst-docs)
+    endforeach()
   endif()
 endif()