absl/copts.bzl

"""absl specific copts.

Flags specified here must not impact ABI. Code compiled with and without these
opts will be linked together, and in some cases headers compiled with and
without these options will be part of the same program.
"""
GCC_FLAGS = [
    "-Wall",
    "-Wextra",
    "-Wcast-qual",
    "-Wconversion-null",
    "-Wmissing-declarations",
    "-Woverlength-strings",
    "-Wpointer-arith",
    "-Wunused-local-typedefs",
    "-Wunused-result",
    "-Wvarargs",
    "-Wvla",  # variable-length array
    "-Wwrite-strings",
    # Google style does not use unsigned integers, though STL containers
    # have unsigned types.
    "-Wno-sign-compare",
]

GCC_TEST_FLAGS = [
    "-Wno-conversion-null",
    "-Wno-missing-declarations",
    "-Wno-sign-compare",
    "-Wno-unused-function",
    "-Wno-unused-parameter",
    "-Wno-unused-private-field",
]

# Docs on single flags is preceded by a comment.
# Docs on groups of flags is preceded by ###.

LLVM_FLAGS = [
    # All warnings are treated as errors by implicit -Werror flag
    "-Wall",
    "-Wextra",
    "-Weverything",
    # Abseil does not support C++98
    "-Wno-c++98-compat-pedantic",
    # Turns off all implicit conversion warnings. Most are re-enabled below.
    "-Wno-conversion",
    "-Wno-covered-switch-default",
    "-Wno-deprecated",
    "-Wno-disabled-macro-expansion",
    "-Wno-double-promotion",
    ###
    # Turned off as they include valid C++ code.
    "-Wno-comma",
    "-Wno-extra-semi",
    "-Wno-packed",
    "-Wno-padded",
    ###
    "-Wno-float-conversion",
    "-Wno-float-equal",
    "-Wno-format-nonliteral",
    # Too aggressive: warns on Clang extensions enclosed in Clang-only
    # compilation paths.
    "-Wno-gcc-compat",
    ###
    # Some internal globals are necessary. Don't do this at home.
    "-Wno-global-constructors",
    "-Wno-exit-time-destructors",
    ###
    "-Wno-nested-anon-types",
    "-Wno-non-modular-include-in-module",
    "-Wno-old-style-cast",
    # Warns on preferred usage of non-POD types such as string_view
    "-Wno-range-loop-analysis",
    "-Wno-reserved-id-macro",
    "-Wno-shorten-64-to-32",
    "-Wno-switch-enum",
    "-Wno-thread-safety-negative",
    "-Wno-undef",
    "-Wno-unknown-warning-option",
    "-Wno-unreachable-code",
    # Causes warnings on include guards
    "-Wno-unused-macros",
    "-Wno-weak-vtables",
    ###
    # Implicit conversion warnings turned off by -Wno-conversion
    # which are re-enabled below.
    "-Wbitfield-enum-conversion",
    "-Wbool-conversion",
    "-Wconstant-conversion",
    "-Wenum-conversion",
    "-Wint-conversion",
    "-Wliteral-conversion",
    "-Wnon-literal-null-conversion",
    "-Wnull-conversion",
    "-Wobjc-literal-conversion",
    "-Wno-sign-conversion",
    "-Wstring-conversion",
    ###
]

LLVM_TEST_FLAGS = [
    "-Wno-c99-extensions",
    "-Wno-missing-noreturn",
    "-Wno-missing-prototypes",
    "-Wno-null-conversion",
    "-Wno-shadow",
    "-Wno-shift-sign-overflow",
    "-Wno-sign-compare",
    "-Wno-unused-function",
    "-Wno-unused-member-function",
    "-Wno-unused-parameter",
    "-Wno-unused-private-field",
    "-Wno-unused-template",
    "-Wno-used-but-marked-unused",
    "-Wno-zero-as-null-pointer-constant",
]

MSVC_FLAGS = [
    "/W3",
    "/WX",
    "/wd4005",  # macro-redefinition
    "/wd4068",  # unknown pragma
    "/wd4244",  # conversion from 'type1' to 'type2', possible loss of data
    "/wd4267",  # conversion from 'size_t' to 'type', possible loss of data
    "/wd4800",  # forcing value to bool 'true' or 'false' (performance warning)
    "/DNOMINMAX",  # Don't define min and max macros (windows.h)
    "/DWIN32_LEAN_AND_MEAN",  # Don't bloat namespace with incompatible winsock versions.
    "/D_CRT_SECURE_NO_WARNINGS",  # Don't warn about usage of insecure C functions
]

MSVC_TEST_FLAGS = [
    "/wd4018",  # signed/unsigned mismatch
    "/wd4101",  # unreferenced local variable
    "/wd4503",  # decorated name length exceeded, name was truncated
]

# /Wall with msvc includes unhelpful warnings such as C4711, C4710, ...
ABSL_DEFAULT_COPTS = select({
    "//absl:windows": MSVC_FLAGS,
    "//absl:llvm_compiler": LLVM_FLAGS,
    "//conditions:default": GCC_FLAGS,
})

# in absence of modules (--compiler=gcc or -c opt), cc_tests leak their copts
# to their (included header) dependencies and fail to build outside absl
ABSL_TEST_COPTS = ABSL_DEFAULT_COPTS + select({
    "//absl:windows": MSVC_TEST_FLAGS,
    "//absl:llvm_compiler": LLVM_TEST_FLAGS,
    "//conditions:default": GCC_TEST_FLAGS,
})

ABSL_EXCEPTIONS_FLAG = select({
    "//absl:windows": ["/U_HAS_EXCEPTIONS", "/D_HAS_EXCEPTIONS=1", "/EHsc"],
    "//conditions:default": ["-fexceptions"],
})