projects / babeltrace.git / blame
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1 | # ============================================================================== |
| 2 | # https://www.gnu.org/software/autoconf-archive/ax_compiler_flags_ldflags.html | |
| 3 | # ============================================================================== | |
| 4 | # | |
| 5 | # SYNOPSIS | |
| 6 | # | |
| 7 | # AX_COMPILER_FLAGS_LDFLAGS([VARIABLE], [IS-RELEASE], [EXTRA-BASE-FLAGS], [EXTRA-YES-FLAGS]) | |
| 8 | # | |
| 9 | # DESCRIPTION | |
| 10 | # | |
| 11 | # Add warning flags for the linker to VARIABLE, which defaults to | |
| 12 | # WARN_LDFLAGS. VARIABLE is AC_SUBST-ed by this macro, but must be | |
| 13 | # manually added to the LDFLAGS variable for each target in the code base. | |
| 14 | # | |
| 15 | # This macro depends on the environment set up by AX_COMPILER_FLAGS. | |
| 16 | # Specifically, it uses the value of $ax_enable_compile_warnings to decide | |
| 17 | # which flags to enable. | |
| 18 | # | |
| 19 | # LICENSE | |
| 20 | # | |
| 21 | # Copyright (c) 2014, 2015 Philip Withnall <philip@tecnocode.co.uk> | |
| 22 | # Copyright (c) 2017, 2018 Reini Urban <rurban@cpan.org> | |
| 23 | # | |
| 24 | # Copying and distribution of this file, with or without modification, are | |
| 25 | # permitted in any medium without royalty provided the copyright notice | |
| 26 | # and this notice are preserved. This file is offered as-is, without any | |
| 27 | # warranty. | |
| 28 | ||
| 29 | #serial 9 | |
| 30 | ||
| 31 | AC_DEFUN([AX_COMPILER_FLAGS_LDFLAGS],[ | |
| 32 | AX_REQUIRE_DEFINED([AX_APPEND_LINK_FLAGS]) | |
| 33 | AX_REQUIRE_DEFINED([AX_APPEND_FLAG]) | |
| 34 | AX_REQUIRE_DEFINED([AX_CHECK_COMPILE_FLAG]) | |
| 35 | AX_REQUIRE_DEFINED([AX_CHECK_LINK_FLAG]) | |
| 36 | ||
| 37 | # Variable names | |
| 38 | m4_define([ax_warn_ldflags_variable], | |
| 39 | [m4_normalize(ifelse([$1],,[WARN_LDFLAGS],[$1]))]) | |
| 40 | ||
| 41 | # Always pass -Werror=unknown-warning-option to get Clang to fail on bad | |
| 42 | # flags, otherwise they are always appended to the warn_ldflags variable, | |
| 43 | # and Clang warns on them for every compilation unit. | |
| 44 | # If this is passed to GCC, it will explode, so the flag must be enabled | |
| 45 | # conditionally. | |
| 46 | AX_CHECK_COMPILE_FLAG([-Werror=unknown-warning-option],[ | |
| 47 | ax_compiler_flags_test="-Werror=unknown-warning-option" | |
| 48 | ],[ | |
| 49 | ax_compiler_flags_test="" | |
| 50 | ]) | |
| 51 | ||
| 52 | AX_CHECK_LINK_FLAG([-Wl,--as-needed], [ | |
| 53 | AX_APPEND_LINK_FLAGS([-Wl,--as-needed], | |
| 54 | [AM_LDFLAGS],[$ax_compiler_flags_test]) | |
| 55 | ]) | |
| 56 | AX_CHECK_LINK_FLAG([-Wl,-z,relro], [ | |
| 57 | AX_APPEND_LINK_FLAGS([-Wl,-z,relro], | |
| 58 | [AM_LDFLAGS],[$ax_compiler_flags_test]) | |
| 59 | ]) | |
| 60 | AX_CHECK_LINK_FLAG([-Wl,-z,now], [ | |
| 61 | AX_APPEND_LINK_FLAGS([-Wl,-z,now], | |
| 62 | [AM_LDFLAGS],[$ax_compiler_flags_test]) | |
| 63 | ]) | |
| 64 | AX_CHECK_LINK_FLAG([-Wl,-z,noexecstack], [ | |
| 65 | AX_APPEND_LINK_FLAGS([-Wl,-z,noexecstack], | |
| 66 | [AM_LDFLAGS],[$ax_compiler_flags_test]) | |
| 67 | ]) | |
| 68 | # textonly, retpolineplt not yet | |
| 69 | ||
| 70 | # macOS and cygwin linker do not have --as-needed | |
| 71 | AX_CHECK_LINK_FLAG([-Wl,--no-as-needed], [ | |
| 72 | ax_compiler_flags_as_needed_option="-Wl,--no-as-needed" | |
| 73 | ], [ | |
| 74 | ax_compiler_flags_as_needed_option="" | |
| 75 | ]) | |
| 76 | ||
| 77 | # macOS linker speaks with a different accent | |
| 78 | ax_compiler_flags_fatal_warnings_option="" | |
| 79 | AX_CHECK_LINK_FLAG([-Wl,--fatal-warnings], [ | |
| 80 | ax_compiler_flags_fatal_warnings_option="-Wl,--fatal-warnings" | |
| 81 | ]) | |
| 82 | AX_CHECK_LINK_FLAG([-Wl,-fatal_warnings], [ | |
| 83 | ax_compiler_flags_fatal_warnings_option="-Wl,-fatal_warnings" | |
| 84 | ]) | |
| 85 | ||
| 86 | # Base flags | |
| 87 | AX_APPEND_LINK_FLAGS([ dnl | |
| 88 | $ax_compiler_flags_as_needed_option dnl | |
| 89 | $3 dnl | |
| 90 | ],ax_warn_ldflags_variable,[$ax_compiler_flags_test]) | |
| 91 | ||
| 92 | AS_IF([test "$ax_enable_compile_warnings" != "no"],[ | |
| 93 | # "yes" flags | |
| 94 | AX_APPEND_LINK_FLAGS([$4 $5 $6 $7], | |
| 95 | ax_warn_ldflags_variable, | |
| 96 | [$ax_compiler_flags_test]) | |
| 97 | ]) | |
| 98 | AS_IF([test "$ax_enable_compile_warnings" = "error"],[ | |
| 99 | # "error" flags; -Werror has to be appended unconditionally because | |
| 100 | # it's not possible to test for | |
| 101 | # | |
| 102 | # suggest-attribute=format is disabled because it gives too many false | |
| 103 | # positives | |
| 104 | AX_APPEND_LINK_FLAGS([ dnl | |
| 105 | $ax_compiler_flags_fatal_warnings_option dnl | |
| 106 | ],ax_warn_ldflags_variable,[$ax_compiler_flags_test]) | |
| 107 | ]) | |
| 108 | ||
| 109 | # Substitute the variables | |
| 110 | AC_SUBST(ax_warn_ldflags_variable) | |
| 111 | ])dnl AX_COMPILER_FLAGS |