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Diffstat (limited to 'm4/ax_compiler_flags_cflags.m4')
-rw-r--r-- | m4/ax_compiler_flags_cflags.m4 | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/m4/ax_compiler_flags_cflags.m4 b/m4/ax_compiler_flags_cflags.m4 new file mode 100644 index 0000000..f470f8f --- /dev/null +++ b/m4/ax_compiler_flags_cflags.m4 @@ -0,0 +1,133 @@ +# ============================================================================ +# http://www.gnu.org/software/autoconf-archive/ax_compiler_flags_cflags.html +# ============================================================================ +# +# SYNOPSIS +# +# AX_COMPILER_FLAGS_CFLAGS([VARIABLE], [IS-RELEASE], [EXTRA-BASE-FLAGS], [EXTRA-YES-FLAGS]) +# +# DESCRIPTION +# +# Add warning flags for the C compiler to VARIABLE, which defaults to +# WARN_CFLAGS. VARIABLE is AC_SUBST-ed by this macro, but must be +# manually added to the CFLAGS variable for each target in the code base. +# +# This macro depends on the environment set up by AX_COMPILER_FLAGS. +# Specifically, it uses the value of $ax_enable_compile_warnings to decide +# which flags to enable. +# +# LICENSE +# +# Copyright (c) 2014, 2015 Philip Withnall <philip@tecnocode.co.uk> +# +# Copying and distribution of this file, with or without modification, are +# permitted in any medium without royalty provided the copyright notice +# and this notice are preserved. This file is offered as-is, without any +# warranty. + +#serial 11 + +AC_DEFUN([AX_COMPILER_FLAGS_CFLAGS],[ + AC_REQUIRE([AC_PROG_SED]) + AX_REQUIRE_DEFINED([AX_APPEND_COMPILE_FLAGS]) + AX_REQUIRE_DEFINED([AX_APPEND_FLAG]) + AX_REQUIRE_DEFINED([AX_CHECK_COMPILE_FLAG]) + + # Variable names + m4_define(ax_warn_cflags_variable, + [m4_normalize(ifelse([$1],,[WARN_CFLAGS],[$1]))]) + + AC_LANG_PUSH([C]) + + # Always pass -Werror=unknown-warning-option to get Clang to fail on bad + # flags, otherwise they are always appended to the warn_cflags variable, and + # Clang warns on them for every compilation unit. + # If this is passed to GCC, it will explode, so the flag must be enabled + # conditionally. + AX_CHECK_COMPILE_FLAG([-Werror=unknown-warning-option],[ + ax_compiler_flags_test="-Werror=unknown-warning-option" + ],[ + ax_compiler_flags_test="" + ]) + + # Base flags + AX_APPEND_COMPILE_FLAGS([ dnl + -fno-strict-aliasing dnl + $3 dnl + ],ax_warn_cflags_variable,[$ax_compiler_flags_test]) + + AS_IF([test "$ax_enable_compile_warnings" != "no"],[ + # "yes" flags + AX_APPEND_COMPILE_FLAGS([ dnl + -Wall dnl + -Wextra dnl + -Wundef dnl + -Wnested-externs dnl + -Wwrite-strings dnl + -Wpointer-arith dnl + -Wmissing-declarations dnl + -Wmissing-prototypes dnl + -Wstrict-prototypes dnl + -Wredundant-decls dnl + -Wno-unused-parameter dnl + -Wno-missing-field-initializers dnl + -Wdeclaration-after-statement dnl + -Wformat=2 dnl + -Wold-style-definition dnl + -Wcast-align dnl + -Wformat-nonliteral dnl + -Wformat-security dnl + -Wsign-compare dnl + -Wstrict-aliasing dnl + -Wshadow dnl + -Winline dnl + -Wpacked dnl + -Wmissing-format-attribute dnl + -Wmissing-noreturn dnl + -Winit-self dnl + -Wredundant-decls dnl + -Wmissing-include-dirs dnl + -Wunused-but-set-variable dnl + -Warray-bounds dnl + -Wimplicit-function-declaration dnl + -Wreturn-type dnl + -Wswitch-enum dnl + -Wswitch-default dnl + $4 dnl + $5 dnl + $6 dnl + $7 dnl + ],ax_warn_cflags_variable,[$ax_compiler_flags_test]) + ]) + AS_IF([test "$ax_enable_compile_warnings" = "error"],[ + # "error" flags; -Werror has to be appended unconditionally because + # it's not possible to test for + # + # suggest-attribute=format is disabled because it gives too many false + # positives + AX_APPEND_FLAG([-Werror],ax_warn_cflags_variable) + + AX_APPEND_COMPILE_FLAGS([ dnl + -Wno-suggest-attribute=format dnl + ],ax_warn_cflags_variable,[$ax_compiler_flags_test]) + ]) + + # In the flags below, when disabling specific flags, always add *both* + # -Wno-foo and -Wno-error=foo. This fixes the situation where (for example) + # we enable -Werror, disable a flag, and a build bot passes CFLAGS=-Wall, + # which effectively turns that flag back on again as an error. + for flag in $ax_warn_cflags_variable; do + AS_CASE([$flag], + [-Wno-*=*],[], + [-Wno-*],[ + AX_APPEND_COMPILE_FLAGS([-Wno-error=$(AS_ECHO([$flag]) | $SED 's/^-Wno-//')], + ax_warn_cflags_variable, + [$ax_compiler_flags_test]) + ]) + done + + AC_LANG_POP([C]) + + # Substitute the variables + AC_SUBST(ax_warn_cflags_variable) +])dnl AX_COMPILER_FLAGS |