| Willy Tarreau | 2fd6dbf | 2022-11-17 09:02:56 +0100 | [diff] [blame] | 1 | # WARNING: Do not change cc-opt, cc-opt-alt or cc-warning without checking if |
| 2 | # clang bug #49364 is fixed. stderr is redirected to /dev/null on |
| 3 | # purpose, to work around a clang 11 bug that crashes if stderr is |
| 4 | # redirected to stdin. |
| 5 | # |
| 6 | # Function used to detect support of a given option by the compiler. |
| 7 | # Usage: CFLAGS += $(call cc-opt,option). Eg: $(call cc-opt,-fwrapv) |
| 8 | # Note: ensure the referencing variable is assigned using ":=" and not "=" to |
| 9 | # call it only once. |
| 10 | cc-opt = $(shell set -e; if $(CC) -Werror $(1) -E -xc - -o /dev/null </dev/null >&0 2>/dev/null; then echo "$(1)"; fi;) |
| 11 | |
| 12 | # same but tries with $2 if $1 is not supported |
| 13 | cc-opt-alt = $(if $(shell set -e; if $(CC) -Werror $(1) -E -xc - -o /dev/null </dev/null >&0 2>/dev/null; then echo 1;fi),$(1),$(call cc-opt,$(2))) |
| 14 | |
| 15 | # validate a list of options one at a time |
| 16 | cc-all-opts = $(foreach a,$(1),$(call cc-opt,$(a))) |
| 17 | |
| 18 | # try to pass plenty of options at once, take them on success or try them |
| 19 | # one at a time on failure and keep successful ones. This is handy to quickly |
| 20 | # validate most common options. |
| 21 | cc-all-fast = $(if $(call cc-opt,$(1)),$(1),$(call cc-all-opts,$(1))) |
| 22 | |
| 23 | # Below we verify that the compiler supports any -Wno-something option to |
| 24 | # disable any warning, or if a special option is needed to achieve that. This |
| 25 | # will allow to get rid of testing when the compiler doesn't care. The result |
| 26 | # is made of two variables: |
| 27 | # - cc-anywno that's non-empty if the compiler supports disabling anything |
| 28 | # - cc-wnouwo that may contain an option needed to enable this behavior |
| 29 | # Gcc 4.x and above do not need any option but will still complain about unknown |
| 30 | # options if another warning or error happens, and as such they're not testable. |
| 31 | # Clang needs a special option -Wno-unknown-warning-option. Compilers not |
| 32 | # supporting this option will check all warnings individually. |
| 33 | cc-anywno := $(call cc-opt,-Wno-haproxy-warning) |
| 34 | cc-wnouwo := $(if $(cc-anywno),,$(call cc-opt,-Wno-unknown-warning-option)) |
| 35 | cc-anywno := $(if $(cc-anywno)$(cc-wnouwo),1) |
| 36 | |
| 37 | # Disable a warning when supported by the compiler. Don't put spaces around the |
| 38 | # warning! And don't use cc-opt which doesn't always report an error until |
| 39 | # another one is also returned. If "cc-anywno" is set, the compiler supports |
| 40 | # -Wno- followed by anything so we don't even need to start the compiler. |
| 41 | # Usage: CFLAGS += $(call cc-nowarn,warning). Eg: $(call cc-opt,format-truncation) |
| 42 | cc-nowarn = $(if $(cc-anywno),-Wno-$(1),$(shell set -e; if $(CC) -Werror -W$(1) -E -xc - -o /dev/null </dev/null >&0 2>/dev/null; then echo "-Wno-$(1)"; fi;)) |