# -*- Mode: python; c-basic-offset: 4; indent-tabs-mode: nil; tab-width: 40 -*- # vim: set filetype=python: # This Source Code Form is subject to the terms of the Mozilla Public # License, v. 2.0. If a copy of the MPL was not distributed with this # file, You can obtain one at http://mozilla.org/MPL/2.0/. option( "--enable-warnings-as-errors", env="MOZ_ENABLE_WARNINGS_AS_ERRORS", default=depends("MOZ_AUTOMATION")(lambda x: bool(x)), help="{Enable|Disable} treating warnings as errors", ) @depends("--enable-warnings-as-errors") def rust_warning_flags(warnings_as_errors): flags = [] # Note that cargo passes --cap-lints warn to rustc for third-party code, so # we don't need a very complicated setup. if warnings_as_errors: flags.append("-Dwarnings") else: flags.extend(("--cap-lints", "warn")) return flags c_warning_flag = dependable("-Werror") @depends("--enable-warnings-as-errors", c_warning_flag) def warnings_as_errors(warnings_as_errors, c_warning_flag): if not warnings_as_errors: return "" return c_warning_flag set_config("WARNINGS_AS_ERRORS", warnings_as_errors) # We have a peculiar setup in old-configure.in where some compilation tests # depend on enabling warnings-as-errors even if it's disabled for Firefox # compilation. We therefore need this assignment. add_old_configure_assignment("WARNINGS_AS_ERRORS", c_warning_flag) # GCC/Clang warnings: # https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html # https://clang.llvm.org/docs/DiagnosticsReference.html # lots of useful warnings add_gcc_warning("-Wall") # catch implicit truncation of enum values assigned to smaller bit fields check_and_add_gcc_warning("-Wbitfield-enum-conversion") # catches bugs, e.g. "if (c); foo();", few false positives add_gcc_warning("-Wempty-body") # catches return types with qualifiers like const add_gcc_warning("-Wignored-qualifiers") # function declaration hides virtual function from base class. # Don't enable for GCC, since it's more strict than clang, # and the additional cases it covers are not valuable. add_gcc_warning( "-Woverloaded-virtual", cxx_compiler, when=depends(cxx_compiler)(lambda c: c.type != "gcc"), ) # catches pointer arithmetic using NULL or sizeof(void) add_gcc_warning("-Wpointer-arith") # catch modifying constructor parameter that shadows member variable check_and_add_gcc_warning("-Wshadow-field-in-constructor-modified") # catches comparing signed/unsigned ints add_gcc_warning("-Wsign-compare") # catches overflow bugs, few false positives add_gcc_warning("-Wtype-limits") # catches some dead code add_gcc_warning("-Wunreachable-code") check_and_add_gcc_warning("-Wunreachable-code-return") # catches treating string literals as non-const add_gcc_warning("-Wwrite-strings", cxx_compiler) # turned on by -Wall, but we use offsetof on non-POD types frequently add_gcc_warning("-Wno-invalid-offsetof", cxx_compiler) # catches objects passed by value to variadic functions. check_and_add_gcc_warning("-Wclass-varargs") # catches empty if/switch/for initialization statements that have no effect check_and_add_gcc_warning("-Wempty-init-stmt", cxx_compiler) # catches some implicit conversion of floats to ints check_and_add_gcc_warning("-Wfloat-overflow-conversion") check_and_add_gcc_warning("-Wfloat-zero-conversion") # catches issues around loops check_and_add_gcc_warning("-Wloop-analysis") # But, disable range-loop-analysis because it can raise unhelpful false # positives. check_and_add_gcc_warning("-Wno-range-loop-analysis") # catches C++ version forward-compat issues check_and_add_gcc_warning("-Wc++2a-compat", cxx_compiler) # catches possible misuse of the comma operator check_and_add_gcc_warning("-Wcomma", cxx_compiler) # catches duplicated conditions in if-else-if chains check_and_add_gcc_warning("-Wduplicated-cond") # catches unintentional switch case fallthroughs check_and_add_gcc_warning("-Wimplicit-fallthrough", cxx_compiler) # catches unused variable/function declarations check_and_add_gcc_warning("-Wunused-function", cxx_compiler) check_and_add_gcc_warning("-Wunused-variable", cxx_compiler) # catches expressions used as a null pointer constant # XXX: at the time of writing, the version of clang used on the OS X test # machines has a bug that causes it to reject some valid files if both # -Wnon-literal-null-conversion and -Wsometimes-uninitialized are # specified. We work around this by instead using # -Werror=non-literal-null-conversion, but we only do that when # --enable-warnings-as-errors is specified so that no unexpected fatal # warnings are produced. check_and_add_gcc_warning( "-Werror=non-literal-null-conversion", when="--enable-warnings-as-errors" ) # catches string literals used in boolean expressions check_and_add_gcc_warning("-Wstring-conversion") # catches comparisons that are always true or false check_and_add_gcc_warning("-Wtautological-overlap-compare") check_and_add_gcc_warning("-Wtautological-unsigned-enum-zero-compare") check_and_add_gcc_warning("-Wtautological-unsigned-zero-compare") # This can be triggered by certain patterns used deliberately in portable code check_and_add_gcc_warning("-Wno-error=tautological-type-limit-compare") # we inline 'new' and 'delete' in mozalloc check_and_add_gcc_warning("-Wno-inline-new-delete", cxx_compiler) # Prevent the following GCC warnings from being treated as errors: # too many false positives check_and_add_gcc_warning("-Wno-error=maybe-uninitialized") # we don't want our builds held hostage when a platform-specific API # becomes deprecated. check_and_add_gcc_warning("-Wno-error=deprecated-declarations") # false positives depending on optimization check_and_add_gcc_warning("-Wno-error=array-bounds") # can't get rid of those PGO warnings check_and_add_gcc_warning("-Wno-error=coverage-mismatch") # -Wbackend-plugin warnings from Android PGO profile-use builds: # error: /builds/worker/workspace/build/src/mozglue/misc/AutoProfilerLabel.cpp: # Function control flow change detected (hash mismatch) # _ZN7mozilla17AutoProfilerLabelD2Ev [-Werror,-Wbackend-plugin] check_and_add_gcc_warning("-Wno-error=backend-plugin") # false positives depending on optimizations check_and_add_gcc_warning("-Wno-error=free-nonheap-object") # Would be a pain to fix all occurrences, for very little gain check_and_add_gcc_warning("-Wno-multistatement-macros") # Disable the -Werror for return-std-move because of a false positive # on nsTAutoStringN: https://bugs.llvm.org/show_bug.cgi?id=37249 check_and_add_gcc_warning("-Wno-error=return-std-move") # Disable the -Werror for -Wclass-memaccess as we have a long # tail of issues to fix check_and_add_gcc_warning("-Wno-error=class-memaccess") # -Watomic-alignment is a new warning in clang 7 that seems way too broad. # https://bugs.llvm.org/show_bug.cgi?id=38593 check_and_add_gcc_warning("-Wno-error=atomic-alignment") # New warning with gcc 9. Not useful # https://bugzilla.mozilla.org/show_bug.cgi?id=1515356 check_and_add_gcc_warning("-Wno-error=deprecated-copy") # catches format/argument mismatches with printf c_format_warning, cxx_format_warning = check_and_add_gcc_warning( "-Wformat", when=depends(target)(lambda t: t.kernel != "WINNT") ) # Add compile-time warnings for unprotected functions and format functions # that represent possible security problems. Enable this only when -Wformat # is enabled, otherwise it is an error check_and_add_gcc_warning( "-Wformat-security", when=c_format_warning & cxx_format_warning ) check_and_add_gcc_warning( "-Wformat-overflow=2", when=c_format_warning & cxx_format_warning ) # Other MinGW specific things with only_when(depends(target)(lambda t: t.kernel == "WINNT")): # When compiling for Windows with gcc, we encounter lots of "#pragma warning"'s # which is an MSVC-only pragma that GCC does not recognize. check_and_add_gcc_warning("-Wno-unknown-pragmas") # When compiling for Windows with gcc, gcc throws false positives and true # positives where the callsite is ifdef-ed out check_and_add_gcc_warning("-Wno-unused-function") # When compiling for Windows with gcc, gcc cannot produce this warning # correctly: it mistakes DWORD_PTR and ULONG_PTR as types you cannot # give NULL to. (You can in fact do that.) check_and_add_gcc_warning("-Wno-conversion-null") # Throughout the codebase we regularly have switch statements off of enums # without covering every value in the enum. We don't care about these warnings. check_and_add_gcc_warning("-Wno-switch") # Another code pattern we have is using start and end constants in enums of # different types. We do this for safety, but then when comparing it throws # an error, which we would like to ignore. This seems to only affect the MinGW # build, but we're not sure why. check_and_add_gcc_warning("-Wno-enum-compare") # We hit this all over the place with the gtest INSTANTIATE_TEST_CASE_P macro check_and_add_gcc_warning("-Wno-gnu-zero-variadic-macro-arguments") # Make it an error to be missing function declarations for C code. check_and_add_gcc_warning("-Werror=implicit-function-declaration", c_compiler) # New in clang 11. We can't really do anything about this warning. check_and_add_gcc_warning("-Wno-psabi") # Disable broken missing-braces warning on old clang versions check_and_add_gcc_warning( "-Wno-missing-braces", when=depends(c_compiler)(lambda c: c.type == "clang" and c.version < "6.0"), ) # Please keep these last in this file add_old_configure_assignment("_WARNINGS_CFLAGS", warnings_flags.cflags) add_old_configure_assignment("_WARNINGS_CXXFLAGS", warnings_flags.cxxflags) add_old_configure_assignment("_WARNINGS_HOST_CFLAGS", warnings_flags.host_cflags) add_old_configure_assignment("_WARNINGS_HOST_CXXFLAGS", warnings_flags.host_cxxflags)