Download libffi at CMake config time (fixes #35)

Drive-by:
- Make Bazel config action more robust
- Disable dependency tracking in libunwind configure

Signed-off-by: Christian Blichmann <mail@blichmann.eu>

cmake/SapiDeps.cmake

@@ -49,6 +49,13 @@ else()
   find_package(Libcap REQUIRED)
 endif()
 
+if(SAPI_DOWNLOAD_LIBFFI)
+  include(cmake/libffi/Download.cmake)
+  check_target(libffi::libffi)
+else()
+  find_package(Libffi REQUIRED)
+endif()
+
 if(SAPI_DOWNLOAD_LIBUNWIND)
   include(cmake/libunwind/Download.cmake)
 endif()
@@ -73,7 +80,6 @@ else()
   find_package(Protobuf REQUIRED)
 endif()
 
-find_package(Libffi REQUIRED)
 if(SAPI_ENABLE_EXAMPLES)
   find_package(ZLIB REQUIRED)
 endif()

cmake/SapiOptions.cmake

@@ -27,7 +27,6 @@ option(SAPI_DOWNLOAD_GLOG "Download glog at config time" ON)
 option(SAPI_DOWNLOAD_PROTOBUF "Download protobuf at config time" ON)
 option(SAPI_DOWNLOAD_LIBUNWIND "Download libunwind at config time" ON)
 option(SAPI_DOWNLOAD_LIBCAP "Download libcap at config time" ON)
-# TODO(cblichmann): Not currently implemented
 option(SAPI_DOWNLOAD_LIBFFI "Download libffi at config time" ON)
 
 option(SAPI_ENABLE_EXAMPLES "Build example code" ON)

cmake/libffi/CMakeLists.txt.in

@@ -0,0 +1,30 @@
+# Copyright 2020 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+cmake_minimum_required(VERSION 3.12)
+project(libffi-download NONE)
+
+include(ExternalProject)
+ExternalProject_Add(libffi
+  URL https://github.com/libffi/libffi/releases/download/v3.3-rc2/libffi-3.3-rc2.tar.gz
+  URL_HASH SHA256=653ffdfc67fbb865f39c7e5df2a071c0beb17206ebfb0a9ecb18a18f63f6b263 # 2019-11-02
+  SOURCE_DIR        "${CMAKE_BINARY_DIR}/libffi-src"
+  CONFIGURE_COMMAND sh -c "./configure            \
+                    --disable-dependency-tracking \
+                    && (mv -t configure-cmake-gen `sh config.guess` || true)"
+  BUILD_COMMAND     ""
+  INSTALL_COMMAND   ""
+  TEST_COMMAND      ""
+  BUILD_IN_SOURCE TRUE
+)

cmake/libffi/Download.cmake

@@ -0,0 +1,73 @@
+# Copyright 2020 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Downloads and unpacks libunwind at configure time
+
+set(workdir "${CMAKE_BINARY_DIR}/libffi-download")
+
+configure_file("${CMAKE_CURRENT_LIST_DIR}/CMakeLists.txt.in"
+               "${workdir}/CMakeLists.txt")
+execute_process(COMMAND ${CMAKE_COMMAND} -G "${CMAKE_GENERATOR}" .
+                RESULT_VARIABLE error
+                WORKING_DIRECTORY "${workdir}")
+if(error)
+  message(FATAL_ERROR "CMake step for ${PROJECT_NAME} failed: ${error}")
+endif()
+
+execute_process(COMMAND ${CMAKE_COMMAND} --build .
+                RESULT_VARIABLE error
+                WORKING_DIRECTORY "${workdir}")
+if(error)
+  message(FATAL_ERROR "Build step for ${PROJECT_NAME} failed: ${error}")
+endif()
+
+set(_ffi_src "${CMAKE_BINARY_DIR}/libffi-src")
+
+set(libffi_INCLUDE_DIR ${_ffi_src}/libffi/include)
+
+add_library(ffi STATIC
+  ${_ffi_src}/configure-cmake-gen/fficonfig.h
+  ${_ffi_src}/configure-cmake-gen/include/ffi.h
+  ${_ffi_src}/configure-cmake-gen/include/ffitarget.h
+  ${_ffi_src}/include/ffi_cfi.h
+  ${_ffi_src}/include/ffi_common.h
+  ${_ffi_src}/src/closures.c
+  ${_ffi_src}/src/debug.c
+  ${_ffi_src}/src/java_raw_api.c
+  ${_ffi_src}/src/prep_cif.c
+  ${_ffi_src}/src/raw_api.c
+  ${_ffi_src}/src/types.c
+  ${_ffi_src}/src/x86/asmnames.h
+  ${_ffi_src}/src/x86/ffi.c
+  ${_ffi_src}/src/x86/ffi64.c
+  ${_ffi_src}/src/x86/ffiw64.c
+  ${_ffi_src}/src/x86/internal.h
+  ${_ffi_src}/src/x86/internal64.h
+  ${_ffi_src}/src/x86/sysv.S
+  ${_ffi_src}/src/x86/unix64.S
+  ${_ffi_src}/src/x86/win64.S
+)
+add_library(libffi::libffi ALIAS ffi)
+target_include_directories(ffi PUBLIC
+  ${_ffi_src}/configure-cmake-gen
+  ${_ffi_src}/configure-cmake-gen/include
+  ${_ffi_src}/include
+)
+target_compile_options(ffi PRIVATE
+  -Wno-vla
+  -Wno-unused-result
+)
+target_link_libraries(ffi PRIVATE
+  sapi::base
+)

cmake/libunwind/CMakeLists.txt.in

@@ -21,6 +21,7 @@ ExternalProject_Add(libunwind
   URL_HASH SHA256=3f3ecb90e28cbe53fba7a4a27ccce7aad188d3210bb1964a923a731a27a75acb
   SOURCE_DIR        "${CMAKE_BINARY_DIR}/libunwind-src"
   CONFIGURE_COMMAND ./configure
+                    --disable-dependency-tracking
                     --disable-documentation
                     --disable-minidebuginfo
                     --disable-shared

sandboxed_api/bazel/repositories.bzl

@@ -23,7 +23,7 @@ def _configure(ctx):
     ctx.execute(
         [bash_exe, "-c", """
                     ./configure --disable-dependency-tracking {args}
-                     mv $(. config.guess) configure-bazel-gen || true
+                     mv -t configure-bazel-gen $(. config.guess) || true
                  """.format(args = " ".join(ctx.attr.configure_args))],
         quiet = ctx.attr.quiet,
     )