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| author | Michal Marek <mmarek@suse.cz> | 2011-05-02 12:51:15 +0200 |
|---|---|---|
| committer | Willy Tarreau <w@1wt.eu> | 2012-02-11 15:40:52 +0100 |
| commit | 1e1df1cdad42883dc7877b9524367531400ce0cb (patch) | |
| tree | 3bffb20861d0c21176adb3f6c7c1c908d6bfad93 | |
| parent | da0acbfbf94229fb2e3cb569d62671d3273939ae (diff) | |
| download | linux-stable-1e1df1cdad42883dc7877b9524367531400ce0cb.tar.gz linux-stable-1e1df1cdad42883dc7877b9524367531400ce0cb.tar.bz2 linux-stable-1e1df1cdad42883dc7877b9524367531400ce0cb.zip | |
kbuild: Fix passing -Wno-* options to gcc 4.4+
commit 8417da6f2128008c431c7d130af6cd3d9079922e upstream.
Starting with 4.4, gcc will happily accept -Wno-<anything> in the
cc-option test and complain later when compiling a file that has some
other warning. This rather unexpected behavior is intentional as per
http://gcc.gnu.org/PR28322, so work around it by testing for support of
the opposite option (without the no-). Introduce a new Makefile function
cc-disable-warning that does this and update two uses of cc-option in
the toplevel Makefile.
Reported-and-tested-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Willy Tarreau <w@1wt.eu>
| -rw-r--r-- | Documentation/kbuild/makefiles.txt | 12 | ||||
| -rw-r--r-- | Makefile | 4 | ||||
| -rw-r--r-- | scripts/Kbuild.include | 5 |
3 files changed, 19 insertions, 2 deletions
diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt index 7a7753321a26..226a3ba6f815 100644 --- a/Documentation/kbuild/makefiles.txt +++ b/Documentation/kbuild/makefiles.txt @@ -471,6 +471,18 @@ more details, with real examples. gcc >= 3.00. For gcc < 3.00, -malign-functions=4 is used. Note: cc-option-align uses KBUILD_CFLAGS for $(CC) options + cc-disable-warning + cc-disable-warning checks if gcc supports a given warning and returns + the commandline switch to disable it. This special function is needed, + because gcc 4.4 and later accept any unknown -Wno-* option and only + warn about it if there is another warning in the source file. + + Example: + KBUILD_CFLAGS += $(call cc-disable-warning, unused-but-set-variable) + + In the above example, -Wno-unused-but-set-variable will be added to + KBUILD_CFLAGS only if gcc really accepts it. + cc-version cc-version returns a numerical version of the $(CC) compiler version. The format is <major><minor> where both are two digits. So for example @@ -531,7 +531,7 @@ endif KBUILD_CFLAGS += $(call cc-option, -fno-stack-protector) # This warning generated too much noise in a regular build. -KBUILD_CFLAGS += $(call cc-option, -Wno-unused-but-set-variable) +KBUILD_CFLAGS += $(call cc-disable-warning, unused-but-set-variable) ifdef CONFIG_FRAME_POINTER KBUILD_CFLAGS += -fno-omit-frame-pointer -fno-optimize-sibling-calls @@ -561,7 +561,7 @@ CHECKFLAGS += $(NOSTDINC_FLAGS) KBUILD_CFLAGS += $(call cc-option,-Wdeclaration-after-statement,) # disable pointer signed / unsigned warnings in gcc 4.0 -KBUILD_CFLAGS += $(call cc-option,-Wno-pointer-sign,) +KBUILD_CFLAGS += $(call cc-disable-warning, pointer-sign) # disable invalid "can't wrap" optimzations for signed / pointers KBUILD_CFLAGS += $(call cc-option,-fno-strict-overflow) diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include index d64e6badc942..88aaeda5b984 100644 --- a/scripts/Kbuild.include +++ b/scripts/Kbuild.include @@ -117,6 +117,11 @@ cc-option-yn = $(call try-run,\ cc-option-align = $(subst -functions=0,,\ $(call cc-option,-falign-functions=0,-malign-functions=0)) +# cc-disable-warning +# Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable) +cc-disable-warning = $(call try-run,\ + $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -W$(strip $(1)) -c -xc /dev/null -o "$$TMP",-Wno-$(strip $(1))) + # cc-version # Usage gcc-ver := $(call cc-version) cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC)) |