Make sure to export the FindProtobuf config after using FetchContent.…

… Build protoc from scratch.
p4lang · Nov 27, 2023 · 3b2b974 · 3b2b974
1 parent ab11c7f
commit 3b2b974
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Showing 4 changed files with 92 additions and 56 deletions.
diff --git a/backends/dpdk/CMakeLists.txt b/backends/dpdk/CMakeLists.txt
@@ -28,7 +28,7 @@ add_custom_target (dpdk_runtime_dir
 # placed in the build directory inside `control-plane` directory
 add_custom_command(
     OUTPUT ${DPDK_P4RUNTIME_INFO_GEN_SRCS} ${DPDK_P4RUNTIME_INFO_GEN_HDRS}
-  COMMAND ${PROTOBUF_PROTOC_EXECUTABLE}
+  COMMAND ${Protobuf_PROTOC_EXECUTABLE}
     --proto_path ${DPDK_P4RUNTIME_DIR}
     --proto_path ${P4RUNTIME_STD_DIR}
     --cpp_out ${CMAKE_CURRENT_BINARY_DIR}/p4/config

diff --git a/backends/p4tools/modules/testgen/targets/bmv2/test/TestTemplate.cmake b/backends/p4tools/modules/testgen/targets/bmv2/test/TestTemplate.cmake
@@ -42,12 +42,21 @@ endmacro(check_bmv2_with_ptf)
 #   - testfolder is target folder of the test.
 function(validate_protobuf testfile testfolder)
   # Find all the proto tests generated for this P4 file and validate their correctness.
-  file(APPEND ${testfile} "txtpbfiles=($(find ${testfolder} -name \"*.txtpb\"  | sort -n ))\n")
-  file(APPEND ${testfile} "for item in \${txtpbfiles[@]}\n")
-  file(APPEND ${testfile} "do\n")
-  file(APPEND ${testfile} "\techo \"Found \${item}\"\n")
-  file(APPEND ${testfile} "\t${PROTOBUF_PROTOC_EXECUTABLE} --proto_path=${CMAKE_CURRENT_LIST_DIR}/../proto --proto_path=${P4RUNTIME_STD_DIR} --proto_path=${P4C_SOURCE_DIR}/control-plane --encode=p4testgen.TestCase p4testgen.proto < \${item}\n")
-  file(APPEND ${testfile} "done\n")
+  file(
+    GENERATE
+    OUTPUT ${testfile}
+    CONTENT
+"txtpbfiles=($(find ${testfolder} -name \"*.txtpb\"  | sort -n ))
+for item in \${txtpbfiles[@]}
+do
+  echo \"Found \${item}\"
+  ${Protobuf_PROTOC_EXECUTABLE} --proto_path=${CMAKE_CURRENT_LIST_DIR}/../proto --proto_path=${P4RUNTIME_STD_DIR} --proto_path=${P4C_SOURCE_DIR}/control-plane --encode=p4testgen.TestCase p4testgen.proto < \${item}
+done"
+  )
+  if(${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.19.0")
+    # TODO: With CMake version 3.20 this can be part of file(GENERATE).
+    file(CHMOD ${testfile} FILE_PERMISSIONS OWNER_READ OWNER_WRITE OWNER_EXECUTE GROUP_READ GROUP_EXECUTE)
+  endif()
 endfunction(validate_protobuf)
 
 # Write the script to validate whether a given protobuf file has a valid format.

diff --git a/cmake/Protobuf.cmake b/cmake/Protobuf.cmake
@@ -13,81 +13,108 @@ macro(p4c_obtain_protobuf)
     endif()
     find_package(Protobuf CONFIG)
     if(NOT Protobuf_FOUND)
-        find_package(Protobuf REQUIRED)
+      find_package(Protobuf REQUIRED)
     endif()
+    # Backwards compatibility
+    # Define camel case versions of input variables
+    foreach(UPPER
+        PROTOBUF_SRC_ROOT_FOLDER
+        PROTOBUF_IMPORT_DIRS
+        PROTOBUF_DEBUG
+        PROTOBUF_LIBRARY
+        PROTOBUF_PROTOC_LIBRARY
+        PROTOBUF_INCLUDE_DIR
+        PROTOBUF_PROTOC_EXECUTABLE
+        PROTOBUF_LIBRARY_DEBUG
+        PROTOBUF_PROTOC_LIBRARY_DEBUG
+        PROTOBUF_LITE_LIBRARY
+        PROTOBUF_LITE_LIBRARY_DEBUG
+        )
+        if (DEFINED ${UPPER})
+            string(REPLACE "PROTOBUF_" "Protobuf_" Camel ${UPPER})
+            if (NOT DEFINED ${Camel})
+                set(${Camel} ${${UPPER}})
+            endif()
+        endif()
+    endforeach()
+
+
     if(ENABLE_PROTOBUF_STATIC)
       set(CMAKE_FIND_LIBRARY_SUFFIXES ${SAVED_CMAKE_FIND_LIBRARY_SUFFIXES})
     endif()
-    set(PROTOBUF_LIBRARY "protobuf::libprotobuf")
-    set(PROTOBUF_PROTOC_EXECUTABLE "protobuf::protoc")
   else()
     # Google introduced another breaking change with protobuf 22.x by adding abseil as a new
     # dependency. https://protobuf.dev/news/2022-08-03/#abseil-dep We do not want abseil, so we stay
     # with 21.x for now.
     set(P4C_PROTOBUF_VERSION "21.12")
     message("Fetching Protobuf version ${P4C_PROTOBUF_VERSION} for P4C...")
 
+    # Unity builds do not work for Protobuf...
+    set(CMAKE_UNITY_BUILD_PREV ${CMAKE_UNITY_BUILD})
+    set(CMAKE_UNITY_BUILD OFF)
     # Print out download state while setting up Protobuf.
     set(FETCHCONTENT_QUIET_PREV ${FETCHCONTENT_QUIET})
     set(FETCHCONTENT_QUIET OFF)
+    # Build Protobuf with position-independent code.
+    set(CMAKE_POSITION_INDEPENDENT_CODE_PREV ${CMAKE_POSITION_INDEPENDENT_CODE})
+    set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+
     set(protobuf_BUILD_TESTS OFF CACHE BOOL "Build tests.")
-    set(protobuf_BUILD_PROTOC_BINARIES OFF CACHE BOOL "Build libprotoc and protoc compiler.")
+    set(protobuf_BUILD_PROTOC_BINARIES ON CACHE BOOL "Build libprotoc and protoc compiler.")
     # Only ever build the static library. It is not safe to link with a local dynamic version.
     set(protobuf_BUILD_SHARED_LIBS OFF CACHE BOOL "Build Shared Libraries")
-    # Unity builds do not work for Protobuf...
-    set(SAVED_CMAKE_UNITY_BUILD ${CMAKE_UNITY_BUILD})
-    set(CMAKE_UNITY_BUILD OFF)
-    fetchcontent_declare(
-      protobuf
-      URL https://github.com/protocolbuffers/protobuf/releases/download/v${P4C_PROTOBUF_VERSION}/protobuf-cpp-3.${P4C_PROTOBUF_VERSION}.tar.gz
-      URL_HASH SHA256=4eab9b524aa5913c6fffb20b2a8abf5ef7f95a80bc0701f3a6dbb4c607f73460
-      USES_TERMINAL_DOWNLOAD TRUE
-      GIT_PROGRESS TRUE
+    # This is necessary to be able to call FindPackage.
+    set(protobuf_INSTALL ON CACHE BOOL "Install Protobuf")
+    # Derive the target architecture in order to build the right architecture.
+    if(CMAKE_HOST_SYSTEM_PROCESSOR STREQUAL "aarch64" OR CMAKE_HOST_SYSTEM_PROCESSOR STREQUAL
+                                                         "arm64"
     )
-
-    # Derive the target architecture in order to download the right zip.
-    if(CMAKE_HOST_SYSTEM_PROCESSOR STREQUAL "aarch64" OR CMAKE_HOST_SYSTEM_PROCESSOR STREQUAL "arm64")
       set(protobuf_ARCH "aarch_64")
-    elseif(CMAKE_HOST_SYSTEM_PROCESSOR STREQUAL "x86_64" OR CMAKE_HOST_SYSTEM_PROCESSOR STREQUAL "amd64")
+    elseif(CMAKE_HOST_SYSTEM_PROCESSOR STREQUAL "x86_64" OR CMAKE_HOST_SYSTEM_PROCESSOR STREQUAL
+                                                            "amd64"
+    )
       set(protobuf_ARCH "x86_64")
     else()
-      MESSAGE(FATAL_ERROR "Unsupported host architecture `${CMAKE_HOST_SYSTEM_PROCESSOR}`")
+      message(FATAL_ERROR "Unsupported host architecture `${CMAKE_HOST_SYSTEM_PROCESSOR}`")
     endif()
 
-    # Pull a different protoc binary for MacOS.
-    # TODO: Should we build from scratch?
-    if(CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang")
-      fetchcontent_declare(
-        protoc
-        URL https://github.com/protocolbuffers/protobuf/releases/download/v${P4C_PROTOBUF_VERSION}/protoc-${P4C_PROTOBUF_VERSION}-osx-${protobuf_ARCH}.zip
-        USES_TERMINAL_DOWNLOAD TRUE
-        GIT_PROGRESS TRUE
-      )
-    else()
-      fetchcontent_declare(
-        protoc
-        URL https://github.com/protocolbuffers/protobuf/releases/download/v${P4C_PROTOBUF_VERSION}/protoc-${P4C_PROTOBUF_VERSION}-linux-${protobuf_ARCH}.zip
-        USES_TERMINAL_DOWNLOAD TRUE
-        GIT_PROGRESS TRUE
-      )
+    # Workaround for a bug in building protoc statically
+    # https://github.com/protocolbuffers/protobuf/issues/4958#issuecomment-510760038
+    if (BUILD_STATIC_RELEASE)
+      set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -pthread -Wl,--no-as-needed")
     endif()
 
-    fetchcontent_makeavailable(protoc)
+    fetchcontent_declare(
+      protobuf
+      URL https://github.com/protocolbuffers/protobuf/releases/download/v${P4C_PROTOBUF_VERSION}/protobuf-cpp-3.${P4C_PROTOBUF_VERSION}.tar.gz
+      URL_HASH SHA256=4eab9b524aa5913c6fffb20b2a8abf5ef7f95a80bc0701f3a6dbb4c607f73460
+      USES_TERMINAL_DOWNLOAD TRUE
+      GIT_PROGRESS TRUE
+    )
+
     # Exclude Protobuf from the main make install step. We only want to use it locally.
     fetchcontent_makeavailable_but_exclude_install(protobuf)
 
-    # Reset unity builds to the previous state...
-    set(CMAKE_UNITY_BUILD ${SAVED_CMAKE_UNITY_BUILD})
-    set(FETCHCONTENT_QUIET ${FETCHCONTENT_QUIET_PREV})
-
-    set(PROTOBUF_PROTOC_EXECUTABLE ${protoc_SOURCE_DIR}/bin/protoc CACHE STRING
-                                                                         "Protoc executable."
-    )
-    set(Protobuf_INCLUDE_DIR ${protobuf_SOURCE_DIR}/src/ CACHE STRING "Protobuf include directory.")
-    set(PROTOBUF_LIBRARY libprotobuf)
-    # Protobuf source code may trigger warnings which we need to ignore.
+    # Protobuf and protoc source code may trigger warnings which we need to ignore.
     set_target_properties(libprotobuf PROPERTIES COMPILE_FLAGS "-Wno-error")
+    set_target_properties(libprotoc PROPERTIES COMPILE_FLAGS "-Wno-error")
+
+    # Add the Protobuf directory to our module path for module builds.
+    list(APPEND CMAKE_MODULE_PATH "${protobuf_BINARY_DIR}/cmake/protobuf")
 
-    message("Done with setting up Protobuf for P4C.")
+    # Set some Protobuf variables manually until we are able to call FindPackage directly.
+    set(Protobuf_FOUND TRUE)
+    set(Protobuf_LIBRARY "protobuf::libprotobuf")
+    set(Protobuf_PROTOC_LIBRARY "protobuf::libprotoc")
+    set(Protobuf_PROTOC_EXECUTABLE $<TARGET_FILE:protoc>)
+    set(Protobuf_INCLUDE_DIR "${protobuf_SOURCE_DIR}/src/")
+
+    # Reset temporary variable modifications.
+    set(CMAKE_UNITY_BUILD ${CMAKE_UNITY_BUILD_PREV})
+    set(FETCHCONTENT_QUIET ${FETCHCONTENT_QUIET_PREV})
+    set(CMAKE_POSITION_INDEPENDENT_CODE ${CMAKE_POSITION_INDEPENDENT_CODE_PREV})
   endif()
+
+
+  message("Done with setting up Protobuf for P4C.")
 endmacro(p4c_obtain_protobuf)
diff --git a/control-plane/CMakeLists.txt b/control-plane/CMakeLists.txt
@@ -51,8 +51,8 @@ set (P4RUNTIME_GEN_PYTHON "control-plane")
 add_custom_target (mkP4configdir
   ${CMAKE_COMMAND} -E make_directory ${CMAKE_BINARY_DIR}/p4/config)
 add_custom_command(OUTPUT ${P4RUNTIME_GEN_SRCS} ${P4RUNTIME_GEN_HDRS}
-  COMMAND ${PROTOBUF_PROTOC_EXECUTABLE}
-          -I ${P4RUNTIME_STD_DIR} -I${CMAKE_CURRENT_SOURCE_DIR}
+  COMMAND ${Protobuf_PROTOC_EXECUTABLE}
+          -I${P4RUNTIME_STD_DIR} -I${CMAKE_CURRENT_SOURCE_DIR} -I${Protobuf_INCLUDE_DIR}
           --cpp_out ${CMAKE_CURRENT_BINARY_DIR}
           --python_out ${CMAKE_CURRENT_BINARY_DIR}
           --experimental_allow_proto3_optional
@@ -96,7 +96,7 @@ add_library(controlplane-gen OBJECT ${P4RUNTIME_GEN_SRCS})
 target_include_directories(controlplane-gen
   SYSTEM BEFORE PUBLIC ${Protobuf_INCLUDE_DIR}
 )
-target_link_libraries (controlplane-gen PUBLIC ${PROTOBUF_LIBRARY})
+target_link_libraries (controlplane-gen PUBLIC ${Protobuf_LIBRARY})
 # Needed for the correct import of google/status.pb.cc
 target_include_directories(
   controlplane-gen PUBLIC ${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_CURRENT_BINARY_DIR}