diff mbox series

[RFC] meson: Run some compiler checks using -Wno-unused-value

Message ID 20241211231655.98148-1-philmd@linaro.org
State Superseded
Headers show
Series [RFC] meson: Run some compiler checks using -Wno-unused-value | expand

Commit Message

Philippe Mathieu-Daudé Dec. 11, 2024, 11:16 p.m. UTC 
When running Clang static analyzer on macOS I'm getting:

  include/qemu/osdep.h:634:8: error: redefinition of 'iovec'
    634 | struct iovec {
        |        ^
  /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/sys/_types/_iovec_t.h:31:8: note: previous definition is here
     31 | struct iovec {
        |        ^
  1 error generated.

Looking at meson-logs.txt, the analyzer enables -Wunused-value
making meson generated code to fail:

    Code:
    #include <sys/uio.h>
            void bar(void) {
                sizeof(struct iovec);
            }
    -----------
    stderr:
    meson-private/tmpe8_1b_00/testfile.c:3:13: error: expression result unused [-Werror,-Wunused-value]
        3 |             sizeof(struct iovec);
          |             ^~~~~~~~~~~~~~~~~~~~
    1 error generated.
    -----------
    Checking for type "struct iovec" : NO

    Code:
    #include <utmpx.h>
            void bar(void) {
                sizeof(struct utmpx);
            }
    -----------
    stderr:
    meson-private/tmp3n0u490p/testfile.c:3:13: error: expression result unused [-Werror,-Wunused-value]
        3 |             sizeof(struct utmpx);
          |             ^~~~~~~~~~~~~~~~~~~~
    1 error generated.
    -----------
    Checking for type "struct utmpx" : NO

    Code:

            #include <getopt.h>
            int main(void) {
                /* If it's not defined as a macro, try to use as a symbol */
                #ifndef optreset
                    optreset;
                #endif
                return 0;
            }
    -----------
    stderr:
    meson-private/tmp1rzob_os/testfile.c:6:17: error: expression result unused [-Werror,-Wunused-value]
        6 |                 optreset;
          |                 ^~~~~~~~
    1 error generated.
    -----------
    Header "getopt.h" has symbol "optreset" : NO

    Code:

            #include <vmnet/vmnet.h>
            int main(void) {
                /* If it's not defined as a macro, try to use as a symbol */
                #ifndef VMNET_BRIDGED_MODE
                    VMNET_BRIDGED_MODE;
                #endif
                return 0;
            }
    -----------
    stderr:
    meson-private/tmpl9jgsxpt/testfile.c:6:17: error: expression result unused [-Werror,-Wunused-value]
        6 |                 VMNET_BRIDGED_MODE;
          |                 ^~~~~~~~~~~~~~~~~~
    1 error generated.
    -----------
    Header "vmnet/vmnet.h" has symbol "VMNET_BRIDGED_MODE" with dependency appleframeworks: NO
    ../meson.build:1174: WARNING: vmnet.framework API is outdated, disabling

Fix by explicitly disabling -Wunused-value from these meson checks.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
RFC: Probably meson should do that in has_header_symbol() / has_type()?
---
 meson.build | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

Comments

Daniel P. Berrangé Dec. 12, 2024, 9:15 a.m. UTC | #1 
On Thu, Dec 12, 2024 at 12:16:55AM +0100, Philippe Mathieu-Daudé wrote:
> When running Clang static analyzer on macOS I'm getting:


snip

> Fix by explicitly disabling -Wunused-value from these meson checks.
> 
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
> RFC: Probably meson should do that in has_header_symbol() / has_type()?

How are you enabling the use of static analyzers ?  There are several
different ways to change compiler options and I vaguely recall some
approaches can trip up meson.


> ---
>  meson.build | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/meson.build b/meson.build
> index 147097c652e..a431aa982ac 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -1166,7 +1166,8 @@ cocoa = dependency('appleframeworks',
>  vmnet = dependency('appleframeworks', modules: 'vmnet', required: get_option('vmnet'))
>  if vmnet.found() and not cc.has_header_symbol('vmnet/vmnet.h',
>                                                'VMNET_BRIDGED_MODE',
> -                                              dependencies: vmnet)
> +                                              dependencies: vmnet,
> +                                              args: '-Wno-unused-value')
>    vmnet = not_found
>    if get_option('vmnet').enabled()
>      error('vmnet.framework API is outdated')
> @@ -2690,7 +2691,7 @@ config_host_data.set('CONFIG_RTNETLINK',
>  config_host_data.set('CONFIG_SYSMACROS',
>                       cc.has_header_symbol('sys/sysmacros.h', 'makedev'))
>  config_host_data.set('HAVE_OPTRESET',
> -                     cc.has_header_symbol('getopt.h', 'optreset'))
> +                     cc.has_header_symbol('getopt.h', 'optreset', args: '-Wno-unused-value'))
>  config_host_data.set('HAVE_IPPROTO_MPTCP',
>                       cc.has_header_symbol('netinet/in.h', 'IPPROTO_MPTCP'))
>  
> @@ -2708,10 +2709,12 @@ config_host_data.set('HAVE_BLK_ZONE_REP_CAPACITY',
>  # has_type
>  config_host_data.set('CONFIG_IOVEC',
>                       cc.has_type('struct iovec',
> -                                 prefix: '#include <sys/uio.h>'))
> +                                 prefix: '#include <sys/uio.h>',
> +                                 args: '-Wno-unused-value'))
>  config_host_data.set('HAVE_UTMPX',
>                       cc.has_type('struct utmpx',
> -                                 prefix: '#include <utmpx.h>'))
> +                                 prefix: '#include <utmpx.h>',
> +                                 args: '-Wno-unused-value'))
>  
>  config_host_data.set('CONFIG_EVENTFD', cc.links('''
>    #include <sys/eventfd.h>
> -- 
> 2.45.2
> 

With regards,
Daniel
Philippe Mathieu-Daudé Dec. 12, 2024, 9:55 a.m. UTC | #2 
On 12/12/24 10:15, Daniel P. Berrangé wrote:
> On Thu, Dec 12, 2024 at 12:16:55AM +0100, Philippe Mathieu-Daudé wrote:
>> When running Clang static analyzer on macOS I'm getting:
> 
> 
> snip
> 
>> Fix by explicitly disabling -Wunused-value from these meson checks.
>>
>> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
>> ---
>> RFC: Probably meson should do that in has_header_symbol() / has_type()?
> 
> How are you enabling the use of static analyzers ?  There are several
> different ways to change compiler options and I vaguely recall some
> approaches can trip up meson.

I prefix my build with 'scan-build':

$ scan-build make
scan-build: Using '/usr/bin/clang' for static analysis
config-host.mak is out-of-date, running configure
C compiler for the host machine: clang (clang 16.0.0 "Apple clang 
version 16.0.0 (clang-1600.0.26.4)")

You can reproduce without using scan-build by passing
--extra-cflags=-Wunused-value to ./configure.

We have a "disable some undesirable warnings" section in
warn_flags[] in meson.build. If we want to ignore unused
we should add it there, but I'd rather not ignore them ;)

> 
>> ---
>>   meson.build | 11 +++++++----
>>   1 file changed, 7 insertions(+), 4 deletions(-)
>>
>> diff --git a/meson.build b/meson.build
>> index 147097c652e..a431aa982ac 100644
>> --- a/meson.build
>> +++ b/meson.build
>> @@ -1166,7 +1166,8 @@ cocoa = dependency('appleframeworks',
>>   vmnet = dependency('appleframeworks', modules: 'vmnet', required: get_option('vmnet'))
>>   if vmnet.found() and not cc.has_header_symbol('vmnet/vmnet.h',
>>                                                 'VMNET_BRIDGED_MODE',
>> -                                              dependencies: vmnet)
>> +                                              dependencies: vmnet,
>> +                                              args: '-Wno-unused-value')
>>     vmnet = not_found
>>     if get_option('vmnet').enabled()
>>       error('vmnet.framework API is outdated')
>> @@ -2690,7 +2691,7 @@ config_host_data.set('CONFIG_RTNETLINK',
>>   config_host_data.set('CONFIG_SYSMACROS',
>>                        cc.has_header_symbol('sys/sysmacros.h', 'makedev'))
>>   config_host_data.set('HAVE_OPTRESET',
>> -                     cc.has_header_symbol('getopt.h', 'optreset'))
>> +                     cc.has_header_symbol('getopt.h', 'optreset', args: '-Wno-unused-value'))
>>   config_host_data.set('HAVE_IPPROTO_MPTCP',
>>                        cc.has_header_symbol('netinet/in.h', 'IPPROTO_MPTCP'))
>>   
>> @@ -2708,10 +2709,12 @@ config_host_data.set('HAVE_BLK_ZONE_REP_CAPACITY',
>>   # has_type
>>   config_host_data.set('CONFIG_IOVEC',
>>                        cc.has_type('struct iovec',
>> -                                 prefix: '#include <sys/uio.h>'))
>> +                                 prefix: '#include <sys/uio.h>',
>> +                                 args: '-Wno-unused-value'))
>>   config_host_data.set('HAVE_UTMPX',
>>                        cc.has_type('struct utmpx',
>> -                                 prefix: '#include <utmpx.h>'))
>> +                                 prefix: '#include <utmpx.h>',
>> +                                 args: '-Wno-unused-value'))
>>   
>>   config_host_data.set('CONFIG_EVENTFD', cc.links('''
>>     #include <sys/eventfd.h>
>> -- 
>> 2.45.2
>>
> 
> With regards,
> Daniel
diff mbox series

Patch

diff --git a/meson.build b/meson.build
index 147097c652e..a431aa982ac 100644
--- a/meson.build
+++ b/meson.build
@@ -1166,7 +1166,8 @@  cocoa = dependency('appleframeworks',
 vmnet = dependency('appleframeworks', modules: 'vmnet', required: get_option('vmnet'))
 if vmnet.found() and not cc.has_header_symbol('vmnet/vmnet.h',
                                               'VMNET_BRIDGED_MODE',
-                                              dependencies: vmnet)
+                                              dependencies: vmnet,
+                                              args: '-Wno-unused-value')
   vmnet = not_found
   if get_option('vmnet').enabled()
     error('vmnet.framework API is outdated')
@@ -2690,7 +2691,7 @@  config_host_data.set('CONFIG_RTNETLINK',
 config_host_data.set('CONFIG_SYSMACROS',
                      cc.has_header_symbol('sys/sysmacros.h', 'makedev'))
 config_host_data.set('HAVE_OPTRESET',
-                     cc.has_header_symbol('getopt.h', 'optreset'))
+                     cc.has_header_symbol('getopt.h', 'optreset', args: '-Wno-unused-value'))
 config_host_data.set('HAVE_IPPROTO_MPTCP',
                      cc.has_header_symbol('netinet/in.h', 'IPPROTO_MPTCP'))
 
@@ -2708,10 +2709,12 @@  config_host_data.set('HAVE_BLK_ZONE_REP_CAPACITY',
 # has_type
 config_host_data.set('CONFIG_IOVEC',
                      cc.has_type('struct iovec',
-                                 prefix: '#include <sys/uio.h>'))
+                                 prefix: '#include <sys/uio.h>',
+                                 args: '-Wno-unused-value'))
 config_host_data.set('HAVE_UTMPX',
                      cc.has_type('struct utmpx',
-                                 prefix: '#include <utmpx.h>'))
+                                 prefix: '#include <utmpx.h>',
+                                 args: '-Wno-unused-value'))
 
 config_host_data.set('CONFIG_EVENTFD', cc.links('''
   #include <sys/eventfd.h>