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| author | Patrick Georgi <pgeorgi@google.com> | 2020-11-20 21:20:15 +0000 |
|---|---|---|
| committer | Commit Bot <commit-bot@chromium.org> | 2020-11-24 10:23:45 +0000 |
| commit | 48195e5878006ac2cf74cb7f02953ab06c68202d (patch) | |
| tree | ddda0f1d52d04ddbee29b82261214718bbfd9b88 | |
| parent | edd222428715125b9ef2a9a8a064fc32a0d0bd24 (diff) | |
| download | vboot-48195e5878006ac2cf74cb7f02953ab06c68202d.tar.gz | |
Makefile: Test for warning flags before using them
Test for warning flags that older gcc versions don't support
and only use them if supported.
BUG=none
TEST=vboot builds with gcc 4.9, ensured with manual tests that the
test_ccflag operator works correctly.
Change-Id: I14c8cbe9a687981f195d481f744db12d8877a3e0
Signed-off-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/2550799
Reviewed-by: Julius Werner <jwerner@chromium.org>
Tested-by: Patrick Georgi <pgeorgi@chromium.org>
Commit-Queue: Patrick Georgi <pgeorgi@chromium.org>
| -rw-r--r-- | Makefile | 31 |
1 files changed, 26 insertions, 5 deletions
@@ -128,9 +128,9 @@ WERROR := -Werror FIRMWARE_FLAGS := -nostdinc -ffreestanding -fno-builtin -fno-stack-protector COMMON_FLAGS := -pipe ${WERROR} -Wall -Wstrict-prototypes -Wtype-limits \ -Wundef -Wmissing-prototypes -Wno-trigraphs -Wredundant-decls -Wshadow \ - -Wwrite-strings -Wstrict-aliasing -Wdate-time -Wno-unknown-warning \ - -Wno-address-of-packed-member -ffunction-sections -fdata-sections \ - -Wimplicit-fallthrough -Wformat -Wno-format-security ${DEBUG_FLAGS} + -Wwrite-strings -Wstrict-aliasing -Wdate-time \ + -ffunction-sections -fdata-sections \ + -Wformat -Wno-format-security ${DEBUG_FLAGS} # FIRMWARE_ARCH is defined if compiling for a firmware target # (coreboot or depthcharge). @@ -153,6 +153,21 @@ CC ?= gcc CFLAGS += -DCHROMEOS_ENVIRONMENT ${COMMON_FLAGS} endif +CFLAGS += -std=gnu11 + +# test_ccflag +# $(1): compiler flags to test +# $(2): code to insert into test snippet +# returns: $(1) if compiler was successful, empty string otherwise +test_ccflag = $(shell \ + printf "$(2)\nvoid _start(void) {}\n" | \ + $(CC) -nostdlib -Werror $(1) -xc -c - -o /dev/null \ + >/dev/null 2>&1 && echo "$(1)") + +COMMON_FLAGS += $(call test_ccflag,-Wimplicit-fallthrough) +COMMON_FLAGS += $(call test_ccflag,-Wno-address-of-packed-member) +COMMON_FLAGS += $(call test_ccflag,-Wno-unknown-warning) + # Needs -Wl because LD is actually set to CC by default. LDFLAGS += -Wl,--gc-sections @@ -247,8 +262,14 @@ ifeq (${FIRMWARE_ARCH},) CFLAGS += -fPIE endif -# These are required to access large disks and files on 32-bit systems. -CFLAGS += -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 +CFLAGS += -D_GNU_SOURCE + +# This is required to access large disks and files on 32-bit systems, +# but if the environment doesn't support it, at least compile support +# for what is possible. +# Pass through cflags_use_64bits to evaluate it only once, here. +cflags_use_64bits := $(call test_ccflag,-D_FILE_OFFSET_BITS=64,\#include <fts.h>) +CFLAGS += $(cflags_use_64bits) # Code coverage ifneq (${COV},) |