On Fri, Nov 11, 2016 at 03:04:35PM +0100, Jiri Slaby wrote: > On 11/11/2016, 03:00 PM, Jiri Olsa wrote: > > On Fri, Nov 11, 2016 at 12:23:25PM +0100, Jiri Slaby wrote: > >> Hi, > >> > >> I am trying a new gcc with new warnings enabled: > >> > >> make O=../a/gcc7/ CC='gcc-7' V=1 kernel/exit.o > >> EXTRA_CFLAGS='-Wimplicit-fallthrough=3' > >> > >> But the build fails when building under tools/: > >> ... > >> make -f /home/latest/linux/tools/build/Makefile.build dir=. obj=fixdep > >> gcc > >> -Wp,-MD,/home/latest/a/gcc7/tools/objtool/.exec-cmd.o.d,-MT,/home/latest/a/gcc7/tools/objtool/exec-cmd.o > >> -Wbad-function-cast -Wdeclaration-after-statement -Wformat-security > >> -Wformat-y2k -Winit-self -Wmissing-declarations -Wmissing-prototypes > >> -Wnested-externs -Wno-system-headers -Wold-style-definition -Wpacked > >> -Wredundant-decls -Wshadow -Wstrict-aliasing=3 -Wstrict-prototypes > >> -Wswitch-default -Wswitch-enum -Wundef -Wwrite-strings -Wformat > >> -Wimplicit-fallthrough=3 -ggdb3 -Wall -Wextra -std=gnu99 -O6 > >> -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -fPIC -Werror > >> -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE > >> -I/home/latest/linux/tools/include/ -I/home/latest/linux/include/uapi > >> -I/home/latest/linux/include -D"BUILD_STR(s)=#s" -c -o > >> /home/latest/a/gcc7/tools/objtool/exec-cmd.o exec-cmd.c > >> gcc: error: unrecognized command line option ‘-Wimplicit-fallthrough=3’; > >> did you mean ‘-Wno-fallthrough’? > >> > >> > >> Apparently, CC is not respected for tools/ dir. > >> > >> Well, it is used (tools/build/Makefile.build): > >> # Compile command > >> quiet_cmd_cc_o_c = CC $@ > >> cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< > >> > >> > >> But I don't know why CFLAGS propagate from Makefile to tools/, but CC > >> doesn't (both are exported)? Any ideas? > > > > so the root Makefile assign CC directly: > > CC = $(CROSS_COMPILE)gcc > > > > we are trying to be a little bit smarter in perf > > and set it only if it's not set by user > > > > # Allow setting CC and AR and LD, or setting CROSS_COMPILE as a prefix. > > $(call allow-override,CC,$(CROSS_COMPILE)gcc) > > $(call allow-override,AR,$(CROSS_COMPILE)ar) > > $(call allow-override,LD,$(CROSS_COMPILE)ld) > > > > I did not check the other tools.. > > Note that I don't care about tools at all. objtool (see the dump above) > is apparently needed to build the kernel proper, so it is built as a > part of kernel. > > BTW shouldn't it use HOSTCC anyway? hum, probably.. adding Josh to the loop jirka -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
