Enable -Werror build for clang on Circle CI

.circleci/config.yml

@@ -377,17 +377,28 @@ jobs:
       BUILD_TYPE: "Release"
       CMAKE_FLAGS: ""
       RUN_TESTS: true
-#  clang_werror:
-#    <<: *job_definition
-#    environment:
-#      CC: clang-7
-#      CXX: clang++-7
-#      BUILD_TOOLSET: clang
-#      APT_COMPILER_PACKAGE: clang-7
-#      CXXFLAGS: "-Werror"
-#      BUILD_TYPE: "Release"
-#      CMAKE_FLAGS: ""
-#      RUN_TESTS: false
+  clang_werror:
+    <<: *job_definition
+    environment:
+      CC: clang-7
+      CXX: clang++-7
+      BUILD_TOOLSET: clang
+      APT_COMPILER_PACKAGE: clang-7
+      CXXFLAGS: ""
+      BUILD_TYPE: "Release"
+      CMAKE_FLAGS: "-DUSE_WERROR=on"
+      RUN_TESTS: false
+  gcc_werror:
+    <<: *job_definition
+    environment:
+      CC: gcc-8
+      CXX: g++-8
+      BUILD_TOOLSET: gcc
+      APT_COMPILER_PACKAGE: "g++-8"
+      CXXFLAGS: ""
+      BUILD_TYPE: "Release"
+      CMAKE_FLAGS: "-DUSE_WERROR=on"
+      RUN_TESTS: false
   gcc_werror:
     <<: *job_definition
     environment:
@@ -484,8 +495,8 @@ workflows:
         <<: *enable_for_tags
     - clang_7_release:
         <<: *enable_for_tags
-#    - clang_werror:
-#        <<: *enable_for_tags
+    - clang_werror:
+        <<: *enable_for_tags
     - gcc_werror:
         <<: *enable_for_tags
     - no_compatibility:

CMakeLists.txt

@@ -18,9 +18,13 @@ require_clang_version(4.0)
 option(BUILD_TESTING "build test cases" OFF)
 option(CRYFS_UPDATE_CHECKS "let cryfs check for updates and security vulnerabilities" ON)
 option(DISABLE_OPENMP "allow building without OpenMP libraries. This will cause performance degradations." OFF)
+
+# The following options are helpful for development and/or CI
+option(USE_WERROR "build with -Werror flag")
 option(USE_CLANG_TIDY "build with clang-tidy checks enabled" OFF)
 option(CLANG_TIDY_WARNINGS_AS_ERRORS "treat clang-tidy warnings as errors" OFF)
 
+
 if (MSVC)
     option(DOKAN_PATH "Location of the Dokan library, e.g. C:\\Program Files\\Dokan\\DokanLibrary-1.1.0" "")
 endif()

cmake-utils/utils.cmake

@@ -56,12 +56,18 @@ endif()
 #  Uses: target_enable_style_warnings(buildtarget)
 #################################################
 function(target_enable_style_warnings TARGET)
-    # Enable compiler options
-    if (NOT MSVC)
-        # TODO Add compiler warnings on MSVC
+    if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
+        # TODO
+    elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang" OR "${CMAKE_CXX_COMPILER_ID}" STREQUAL "AppleClang")
+        target_compile_options(${TARGET} PRIVATE -Wall -Wextra -Wold-style-cast -Wcast-align -Wno-unused-command-line-argument) # TODO consider -Wpedantic -Wchkp -Wcast-qual -Wctor-dtor-privacy -Wdisabled-optimization -Wformat=2 -Winit-self -Wlogical-op -Wmissing-include-dirs -Wnoexcept -Wold-style-cast -Woverloaded-virtual -Wredundant-decls -Wshadow -Wsign-promo -Wstrict-null-sentinel -Wstrict-overflow=5 -Wundef -Wno-unused -Wno-variadic-macros -Wno-parentheses -fdiagnostics-show-option -Wconversion and others?
+    elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
         target_compile_options(${TARGET} PRIVATE -Wall -Wextra -Wold-style-cast -Wcast-align) # TODO consider -Wpedantic -Wchkp -Wcast-qual -Wctor-dtor-privacy -Wdisabled-optimization -Wformat=2 -Winit-self -Wlogical-op -Wmissing-include-dirs -Wnoexcept -Wold-style-cast -Woverloaded-virtual -Wredundant-decls -Wshadow -Wsign-promo -Wstrict-null-sentinel -Wstrict-overflow=5 -Wundef -Wno-unused -Wno-variadic-macros -Wno-parentheses -fdiagnostics-show-option -Wconversion and others?
     endif()
 
+    if (USE_WERROR)
+        target_compile_options(${TARGET} PRIVATE -Werror)
+    endif()
+
     # Enable clang-tidy
     if(USE_CLANG_TIDY)
         set_target_properties(

src/cpp-utils/assert/backtrace_nonwindows.cpp

@@ -97,9 +97,12 @@ namespace {
     }
     void set_handler(int signum, void(*handler)(int)) {
         auto result = signal(signum, handler);
+#pragma GCC diagnostic push // SIG_ERR uses old style casts
+#pragma GCC diagnostic ignored "-Wold-style-cast"
         if (SIG_ERR == result) {
             LOG(ERR, "Failed to set signal {} handler. Errno: {}", signum, errno);
         }
+#pragma GCC diagnostic pop
     }
 }
 

src/cpp-utils/process/subprocess.cpp

@@ -57,11 +57,14 @@ namespace cpputils {
 			if (returncode == -1) {
 				throw std::runtime_error("Error calling pclose. Errno: " + std::to_string(errno));
 			}
+#pragma GCC diagnostic push // WIFEXITSTATUS / WEXITSTATUS use old style casts
+#pragma GCC diagnostic ignored "-Wold-style-cast"
 			if (!WIFEXITED(returncode)) {
 				// WEXITSTATUS is only valid if WIFEXITED is 0.
 				throw std::runtime_error("WIFEXITED returned " + std::to_string(WIFEXITED(returncode)));
 			}
 			return WEXITSTATUS(returncode);
+#pragma GCC diagnostic pop
 		}
 
 	private: