diff mbox series

[kvm-unit-tests,3/3] Makefile: use "-Werror" in cc-option

Message ID 20191010183506.129921-4-morbo@google.com (mailing list archive)
State New, archived
Headers show
Series Patches for clang compilation | expand

Commit Message

Bill Wendling Oct. 10, 2019, 6:35 p.m. UTC
The "cc-option" macro should use "-Werror" to determine if a flag is
supported. Otherwise the test may not return a nonzero result. Also
conditionalize some of the warning flags which aren't supported by
clang.

Signed-off-by: Bill Wendling <morbo@google.com>
---
 Makefile | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

Comments

Thomas Huth Oct. 15, 2019, 7:29 a.m. UTC | #1
On 10/10/2019 20.35, Bill Wendling wrote:
> The "cc-option" macro should use "-Werror" to determine if a flag is
> supported. Otherwise the test may not return a nonzero result. Also
> conditionalize some of the warning flags which aren't supported by
> clang.
> 
> Signed-off-by: Bill Wendling <morbo@google.com>
> ---
>  Makefile | 19 +++++++++++--------
>  1 file changed, 11 insertions(+), 8 deletions(-)
> 
> diff --git a/Makefile b/Makefile
> index 32414dc..3ec0458 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -46,30 +46,33 @@ include $(SRCDIR)/$(TEST_DIR)/Makefile
>  # cc-option
>  # Usage: OP_CFLAGS+=$(call cc-option, -falign-functions=0, -malign-functions=0)
>  
> -cc-option = $(shell if $(CC) $(1) -S -o /dev/null -xc /dev/null \
> +cc-option = $(shell if $(CC) -Werror $(1) -S -o /dev/null -xc /dev/null \
>                > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;)
>  
>  COMMON_CFLAGS += -g $(autodepend-flags)
> -COMMON_CFLAGS += -Wall -Wwrite-strings -Wclobbered -Wempty-body -Wuninitialized
> -COMMON_CFLAGS += -Wignored-qualifiers -Wunused-but-set-parameter
> -COMMON_CFLAGS += -Werror
> +COMMON_CFLAGS += -Wall -Wwrite-strings -Wempty-body -Wuninitialized
> +COMMON_CFLAGS += -Wignored-qualifiers -Werror
> +
>  frame-pointer-flag=-f$(if $(KEEP_FRAME_POINTER),no-,)omit-frame-pointer
>  fomit_frame_pointer := $(call cc-option, $(frame-pointer-flag), "")
>  fnostack_protector := $(call cc-option, -fno-stack-protector, "")
>  fnostack_protector_all := $(call cc-option, -fno-stack-protector-all, "")
> -wno_frame_address := $(call cc-option, -Wno-frame-address, "")
>  fno_pic := $(call cc-option, -fno-pic, "")
>  no_pie := $(call cc-option, -no-pie, "")
>  COMMON_CFLAGS += $(fomit_frame_pointer)
>  COMMON_CFLAGS += $(fno_stack_protector)
>  COMMON_CFLAGS += $(fno_stack_protector_all)
> -COMMON_CFLAGS += $(wno_frame_address)
>  COMMON_CFLAGS += $(if $(U32_LONG_FMT),-D__U32_LONG_FMT__,)
>  COMMON_CFLAGS += $(fno_pic) $(no_pie)
>  
> +COMMON_CFLAGS += $(call cc-option, -Wno-frame-address, "")

I think the old code used ":=" on purpose, so that the test is only done
once. With your new code, the test is now done each time COMMON_CFLAGS
gets evaluated, i.e. for each compiled object.

Could you please rewrite this test to use the ":=" detour for all lines
that call cc-option?

 Thanks,
  Thomas
Bill Wendling Oct. 15, 2019, 7:57 a.m. UTC | #2
On Tue, Oct 15, 2019 at 12:29 AM Thomas Huth <thuth@redhat.com> wrote:
>
> On 10/10/2019 20.35, Bill Wendling wrote:
> > The "cc-option" macro should use "-Werror" to determine if a flag is
> > supported. Otherwise the test may not return a nonzero result. Also
> > conditionalize some of the warning flags which aren't supported by
> > clang.
> >
> > Signed-off-by: Bill Wendling <morbo@google.com>
> > ---
> >  Makefile | 19 +++++++++++--------
> >  1 file changed, 11 insertions(+), 8 deletions(-)
> >
> > diff --git a/Makefile b/Makefile
> > index 32414dc..3ec0458 100644
> > --- a/Makefile
> > +++ b/Makefile
> > @@ -46,30 +46,33 @@ include $(SRCDIR)/$(TEST_DIR)/Makefile
> >  # cc-option
> >  # Usage: OP_CFLAGS+=$(call cc-option, -falign-functions=0, -malign-functions=0)
> >
> > -cc-option = $(shell if $(CC) $(1) -S -o /dev/null -xc /dev/null \
> > +cc-option = $(shell if $(CC) -Werror $(1) -S -o /dev/null -xc /dev/null \
> >                > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;)
> >
> >  COMMON_CFLAGS += -g $(autodepend-flags)
> > -COMMON_CFLAGS += -Wall -Wwrite-strings -Wclobbered -Wempty-body -Wuninitialized
> > -COMMON_CFLAGS += -Wignored-qualifiers -Wunused-but-set-parameter
> > -COMMON_CFLAGS += -Werror
> > +COMMON_CFLAGS += -Wall -Wwrite-strings -Wempty-body -Wuninitialized
> > +COMMON_CFLAGS += -Wignored-qualifiers -Werror
> > +
> >  frame-pointer-flag=-f$(if $(KEEP_FRAME_POINTER),no-,)omit-frame-pointer
> >  fomit_frame_pointer := $(call cc-option, $(frame-pointer-flag), "")
> >  fnostack_protector := $(call cc-option, -fno-stack-protector, "")
> >  fnostack_protector_all := $(call cc-option, -fno-stack-protector-all, "")
> > -wno_frame_address := $(call cc-option, -Wno-frame-address, "")
> >  fno_pic := $(call cc-option, -fno-pic, "")
> >  no_pie := $(call cc-option, -no-pie, "")
> >  COMMON_CFLAGS += $(fomit_frame_pointer)
> >  COMMON_CFLAGS += $(fno_stack_protector)
> >  COMMON_CFLAGS += $(fno_stack_protector_all)
> > -COMMON_CFLAGS += $(wno_frame_address)
> >  COMMON_CFLAGS += $(if $(U32_LONG_FMT),-D__U32_LONG_FMT__,)
> >  COMMON_CFLAGS += $(fno_pic) $(no_pie)
> >
> > +COMMON_CFLAGS += $(call cc-option, -Wno-frame-address, "")
>
> I think the old code used ":=" on purpose, so that the test is only done
> once. With your new code, the test is now done each time COMMON_CFLAGS
> gets evaluated, i.e. for each compiled object.
>
> Could you please rewrite this test to use the ":=" detour for all lines
> that call cc-option?
>
Does it rerun the "cc-option" call if the COMMON_CFLAGS is initially
defined with ":="? I ask because the kernel calls its version of
cc-option in the way I have it above, but the original definition of
the variable uses ":=".

-bw
Thomas Huth Oct. 15, 2019, 8:12 a.m. UTC | #3
On 15/10/2019 09.57, Bill Wendling wrote:
> On Tue, Oct 15, 2019 at 12:29 AM Thomas Huth <thuth@redhat.com> wrote:
>>
>> On 10/10/2019 20.35, Bill Wendling wrote:
>>> The "cc-option" macro should use "-Werror" to determine if a flag is
>>> supported. Otherwise the test may not return a nonzero result. Also
>>> conditionalize some of the warning flags which aren't supported by
>>> clang.
>>>
>>> Signed-off-by: Bill Wendling <morbo@google.com>
>>> ---
>>>  Makefile | 19 +++++++++++--------
>>>  1 file changed, 11 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/Makefile b/Makefile
>>> index 32414dc..3ec0458 100644
>>> --- a/Makefile
>>> +++ b/Makefile
>>> @@ -46,30 +46,33 @@ include $(SRCDIR)/$(TEST_DIR)/Makefile
>>>  # cc-option
>>>  # Usage: OP_CFLAGS+=$(call cc-option, -falign-functions=0, -malign-functions=0)
>>>
>>> -cc-option = $(shell if $(CC) $(1) -S -o /dev/null -xc /dev/null \
>>> +cc-option = $(shell if $(CC) -Werror $(1) -S -o /dev/null -xc /dev/null \
>>>                > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;)
>>>
>>>  COMMON_CFLAGS += -g $(autodepend-flags)
>>> -COMMON_CFLAGS += -Wall -Wwrite-strings -Wclobbered -Wempty-body -Wuninitialized
>>> -COMMON_CFLAGS += -Wignored-qualifiers -Wunused-but-set-parameter
>>> -COMMON_CFLAGS += -Werror
>>> +COMMON_CFLAGS += -Wall -Wwrite-strings -Wempty-body -Wuninitialized
>>> +COMMON_CFLAGS += -Wignored-qualifiers -Werror
>>> +
>>>  frame-pointer-flag=-f$(if $(KEEP_FRAME_POINTER),no-,)omit-frame-pointer
>>>  fomit_frame_pointer := $(call cc-option, $(frame-pointer-flag), "")
>>>  fnostack_protector := $(call cc-option, -fno-stack-protector, "")
>>>  fnostack_protector_all := $(call cc-option, -fno-stack-protector-all, "")
>>> -wno_frame_address := $(call cc-option, -Wno-frame-address, "")
>>>  fno_pic := $(call cc-option, -fno-pic, "")
>>>  no_pie := $(call cc-option, -no-pie, "")
>>>  COMMON_CFLAGS += $(fomit_frame_pointer)
>>>  COMMON_CFLAGS += $(fno_stack_protector)
>>>  COMMON_CFLAGS += $(fno_stack_protector_all)
>>> -COMMON_CFLAGS += $(wno_frame_address)
>>>  COMMON_CFLAGS += $(if $(U32_LONG_FMT),-D__U32_LONG_FMT__,)
>>>  COMMON_CFLAGS += $(fno_pic) $(no_pie)
>>>
>>> +COMMON_CFLAGS += $(call cc-option, -Wno-frame-address, "")
>>
>> I think the old code used ":=" on purpose, so that the test is only done
>> once. With your new code, the test is now done each time COMMON_CFLAGS
>> gets evaluated, i.e. for each compiled object.
>>
>> Could you please rewrite this test to use the ":=" detour for all lines
>> that call cc-option?
>>
> Does it rerun the "cc-option" call if the COMMON_CFLAGS is initially
> defined with ":="?

It does not rerun the "cc-option" call in that case, but compilation
fails. I think it's likely due to the line that contains the "$(if
$(U32_LONG_FMT),-D__U32_LONG_FMT__,)" since that likely needs to be
evaluated dynamically.

 Thomas
diff mbox series

Patch

diff --git a/Makefile b/Makefile
index 32414dc..3ec0458 100644
--- a/Makefile
+++ b/Makefile
@@ -46,30 +46,33 @@  include $(SRCDIR)/$(TEST_DIR)/Makefile
 # cc-option
 # Usage: OP_CFLAGS+=$(call cc-option, -falign-functions=0, -malign-functions=0)
 
-cc-option = $(shell if $(CC) $(1) -S -o /dev/null -xc /dev/null \
+cc-option = $(shell if $(CC) -Werror $(1) -S -o /dev/null -xc /dev/null \
               > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;)
 
 COMMON_CFLAGS += -g $(autodepend-flags)
-COMMON_CFLAGS += -Wall -Wwrite-strings -Wclobbered -Wempty-body -Wuninitialized
-COMMON_CFLAGS += -Wignored-qualifiers -Wunused-but-set-parameter
-COMMON_CFLAGS += -Werror
+COMMON_CFLAGS += -Wall -Wwrite-strings -Wempty-body -Wuninitialized
+COMMON_CFLAGS += -Wignored-qualifiers -Werror
+
 frame-pointer-flag=-f$(if $(KEEP_FRAME_POINTER),no-,)omit-frame-pointer
 fomit_frame_pointer := $(call cc-option, $(frame-pointer-flag), "")
 fnostack_protector := $(call cc-option, -fno-stack-protector, "")
 fnostack_protector_all := $(call cc-option, -fno-stack-protector-all, "")
-wno_frame_address := $(call cc-option, -Wno-frame-address, "")
 fno_pic := $(call cc-option, -fno-pic, "")
 no_pie := $(call cc-option, -no-pie, "")
 COMMON_CFLAGS += $(fomit_frame_pointer)
 COMMON_CFLAGS += $(fno_stack_protector)
 COMMON_CFLAGS += $(fno_stack_protector_all)
-COMMON_CFLAGS += $(wno_frame_address)
 COMMON_CFLAGS += $(if $(U32_LONG_FMT),-D__U32_LONG_FMT__,)
 COMMON_CFLAGS += $(fno_pic) $(no_pie)
 
+COMMON_CFLAGS += $(call cc-option, -Wno-frame-address, "")
+COMMON_CFLAGS += $(call cc-option, -Wclobbered, "")
+COMMON_CFLAGS += $(call cc-option, -Wunused-but-set-parameter, "")
+COMMON_CFLAGS += $(call cc-option, -Wmissing-parameter-type, "")
+COMMON_CFLAGS += $(call cc-option, -Wold-style-declaration, "")
+
 CFLAGS += $(COMMON_CFLAGS)
-CFLAGS += -Wmissing-parameter-type -Wold-style-declaration -Woverride-init
-CFLAGS += -Wmissing-prototypes -Wstrict-prototypes
+CFLAGS += -Woverride-init -Wmissing-prototypes -Wstrict-prototypes
 
 CXXFLAGS += $(COMMON_CFLAGS)