kbuild: Fix gcc -x syntax
Subsystems (4)
PATCH 1/1 kbuild: Fix gcc -x syntax
The correct syntax for gcc -x is "gcc -x assembler", not "gcc -xassembler". Even though the latter happens to work, the former is what is documented in the manual page and thus what gcc wrappers such as icecream do expect.
This isn't a cosmetic change. The missing space prevents icecream from recognizing compilation tasks it can't handle, leading to silent kernel miscompilations.
Besides me, credits go to Richard Guenther and Dirk Mueller for investigating the miscompilation issue and tracking it down to this incorrect -x parameter syntax.
--- arch/mips/Makefile | 2 +- arch/mips/kernel/Makefile | 2 +- arch/x86/Makefile | 2 +- scripts/Kbuild.include | 12 ++++++------ tools/power/cpupower/Makefile | 2 +- 5 files changed, 10 insertions(+), 10 deletions(-)
arch/mips/Makefile +1 -1
@@ -225,7 +225,7 @@ KBUILD_CPPFLAGS += -DDATAOFFSET=$(if $(d LDFLAGS += -m $(ld-emul) ifdef CONFIG_MIPS -CHECKFLAGS += $(shell $(CC) $(KBUILD_CFLAGS) -dM -E -xc /dev/null | \ +CHECKFLAGS += $(shell $(CC) $(KBUILD_CFLAGS) -dM -E -x c /dev/null | \ egrep -vw '__GNUC_(|MINOR_|PATCHLEVEL_)_' | \ sed -e "s/^\#define /-D'/" -e "s/ /'='/" -e "s/$$/'/") ifdef CONFIG_64BIT
arch/mips/kernel/Makefile +1 -1
@@ -104,7 +104,7 @@ obj-$(CONFIG_MIPS_MACHINE) += mips_machi obj-$(CONFIG_OF) += prom.o -CFLAGS_cpu-bugs64.o = $(shell if $(CC) $(KBUILD_CFLAGS) -Wa,-mdaddi -c -o /dev/null -xc /dev/null >/dev/null 2>&1; then echo "-DHAVE_AS_SET_DADDI"; fi) +CFLAGS_cpu-bugs64.o = $(shell if $(CC) $(KBUILD_CFLAGS) -Wa,-mdaddi -c -o /dev/null -x c /dev/null >/dev/null 2>&1; then echo "-DHAVE_AS_SET_DADDI"; fi) obj-$(CONFIG_HAVE_STD_PC_SERIAL_PORT) += 8250-platform.o
arch/x86/Makefile +1 -1
@@ -92,7 +92,7 @@ endif ifdef CONFIG_X86_X32 x32_ld_ok := $(call try-run,\ /bin/echo -e '1: .quad 1b' | \ - $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" - && \ + $(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" - && \ $(OBJCOPY) -O elf32-x86-64 "$$TMP" "$$TMPO" && \ $(LD) -m elf32_x86_64 "$$TMPO" -o "$$TMP",y,n) ifeq ($(x32_ld_ok),y)
scripts/Kbuild.include +6 -6
@@ -98,24 +98,24 @@ try-run = $(shell set -e; \ # Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,) as-option = $(call try-run,\ - $(CC) $(KBUILD_CFLAGS) $(1) -c -xassembler /dev/null -o "$$TMP",$(1),$(2)) + $(CC) $(KBUILD_CFLAGS) $(1) -c -x assembler /dev/null -o "$$TMP",$(1),$(2)) # as-instr # Usage: cflags-y += $(call as-instr,instr,option1,option2) as-instr = $(call try-run,\ - printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3)) + printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" -,$(2),$(3)) # cc-option # Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586) cc-option = $(call try-run,\ - $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -xc /dev/null -o "$$TMP",$(1),$(2)) + $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2)) # cc-option-yn # Usage: flag := $(call cc-option-yn,-march=winchip-c6) cc-option-yn = $(call try-run,\ - $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -xc /dev/null -o "$$TMP",y,n) + $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",y,n) # cc-option-align # Prefix align with either -falign or -malign
@@ -125,7 +125,7 @@ cc-option-align = $(subst -functions=0,, # cc-disable-warning # Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable) cc-disable-warning = $(call try-run,\ - $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -W$(strip $(1)) -c -xc /dev/null -o "$$TMP",-Wno-$(strip $(1))) + $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1))) # cc-version # Usage gcc-ver := $(call cc-version)
@@ -143,7 +143,7 @@ cc-ifversion = $(shell [ $(call cc-versi # cc-ldoption # Usage: ldflags += $(call cc-ldoption, -Wl$(comma)--hash-style=both) cc-ldoption = $(call try-run,\ - $(CC) $(1) -nostdlib -xc /dev/null -o "$$TMP",$(1),$(2)) + $(CC) $(1) -nostdlib -x c /dev/null -o "$$TMP",$(1),$(2)) # ld-option # Usage: LDFLAGS += $(call ld-option, -X)
tools/power/cpupower/Makefile +1 -1
@@ -111,7 +111,7 @@ GMO_FILES = ${shell for HLANG in ${LANGU export CROSS CC AR STRIP RANLIB CFLAGS LDFLAGS LIB_OBJS # check if compiler option is supported -cc-supports = ${shell if $(CC) ${1} -S -o /dev/null -xc /dev/null > /dev/null 2>&1; then echo "$(1)"; fi;} +cc-supports = ${shell if $(CC) ${1} -S -o /dev/null -x c /dev/null > /dev/null 2>&1; then echo "$(1)"; fi;} # use '-Os' optimization if available, else use -O2 OPTIMIZATION := $(call cc-supports,-Os,-O2)
Signature · 2 lines
Jean Delvare Suse L3
Quoted 8 lines · Jean Delvare
The correct syntax for gcc -x is "gcc -x assembler", not "gcc -xassembler". Even though the latter happens to work, the former is what is documented in the manual page and thus what gcc wrappers such as icecream do expect.
This isn't a cosmetic change. The missing space prevents icecream from recognizing compilation tasks it can't handle, leading to silent kernel miscompilations.
Although we can apply this patch, it won't solve the problem of building older kernels (and bisecting, etc.).
Wouldn't it be prudent to increase the compatibility of icecream, so that it accepts what GCC accepts in practice, such as -xassembler?
Thanks,
Ingo
Hi,
Quoted 11 lines · Ingo Molnar
Quoted 8 lines · Jean Delvare
The correct syntax for gcc -x is "gcc -x assembler", not "gcc -xassembler". Even though the latter happens to work, the former is what is documented in the manual page and thus what gcc wrappers such as icecream do expect.
This isn't a cosmetic change. The missing space prevents icecream from recognizing compilation tasks it can't handle, leading to silent kernel miscompilations.
Quoted 6 lines
Although we can apply this patch, it won't solve the problem of building older kernels (and bisecting, etc.).
Wouldn't it be prudent to increase the compatibility of icecream, so that it accepts what GCC accepts in practice, such as -xassembler?
Wouldn't it make sense to do both? Using the documented syntax in the build system *and* increase compatibility in 3rd party tools?
Regards,
Bernhard
Quoted 17 lines · Bernhard Walle
Hi,
Quoted 14 lines · Ingo Molnar
Quoted 8 lines · Jean Delvare
The correct syntax for gcc -x is "gcc -x assembler", not "gcc -xassembler". Even though the latter happens to work, the former is what is documented in the manual page and thus what gcc wrappers such as icecream do expect.
This isn't a cosmetic change. The missing space prevents icecream from recognizing compilation tasks it can't handle, leading to silent kernel miscompilations.
Although we can apply this patch, it won't solve the problem of building older kernels (and bisecting, etc.).
Quoted 7 lines
Quoted 3 lines
Wouldn't it be prudent to increase the compatibility of icecream, so that it accepts what GCC accepts in practice, such as -xassembler?
Wouldn't it make sense to do both? Using the documented syntax in the build system *and* increase compatibility in 3rd party tools?
Yes.
Thanks,
Ingo
Hi Ingo, hi Bernhard,
Quoted 8 lines · Bernhard Walle
Quoted 7 lines · Ingo Molnar
Quoted 5 lines · Jean Delvare
The correct syntax for gcc -x is "gcc -x assembler", not "gcc -xassembler". Even though the latter happens to work, the former is what is documented in the manual page and thus what gcc wrappers such as icecream do expect.
Quoted 6 lines
Quoted 6 lines
Quoted 3 lines
This isn't a cosmetic change. The missing space prevents icecream from recognizing compilation tasks it can't handle, leading to silent kernel miscompilations.
Although we can apply this patch, it won't solve the problem of building older kernels (and bisecting, etc.).
WRT older kernels, I recommend that we apply the fix to all stable and longterm kernel branches.
Quoted 6 lines
Quoted 3 lines
Wouldn't it be prudent to increase the compatibility of icecream, so that it accepts what GCC accepts in practice, such as -xassembler?
Wouldn't it make sense to do both? Using the documented syntax in the build system *and* increase compatibility in 3rd party tools?
Yes of course, this is exactly the plan. Silent micompilations are very painful so we want to fix the problem on every side we can.
Thanks,
Signature · 2 lines
Jean Delvare Suse L3