[Qemu-devel] [PATCH] split c and cxx extra flags

[Qemu-devel] [PATCH] split c and cxx extra flags

[Bruno Dominguez]

There was no possibility to add specific cxx flags using the configure
file. So A new entrance has been created to support it.

Duplication of information in configure and rules.mak. Taking
QEMU_CFLAGS and add them to QEMU_CXXFLAGS, now the value of
QEMU_CXXFLAGS is stored in config-host.mak, so there is no need for
it.

The makefile for libvixl was adding flags for QEMU_CXXFLAGS in
QEMU_CFLAGS because of the addition in rules.mak. That was removed, so
adding them where it should be.

-----
Signed-off-by: Bruno Dominguez <bru.dominguez@gmail.com>
-----

diff --git a/configure b/configure
index 0586ec9..2fff3cc 100755
--- a/configure
+++ b/configure
@@ -91,7 +91,8 @@ update_cxxflags() {
     # Set QEMU_CXXFLAGS from QEMU_CFLAGS by filtering out those
     # options which some versions of GCC's C++ compiler complain about
     # because they only make sense for C programs.
-    QEMU_CXXFLAGS=
+    QEMU_CXXFLAGS="$QEMU_CXXFLAGS -D__STDC_LIMIT_MACROS"
+
     for arg in $QEMU_CFLAGS; do
         case $arg in
             -Wstrict-prototypes|-Wmissing-prototypes|-Wnested-externs|\
@@ -102,6 +103,8 @@ update_cxxflags() {
                 ;;
         esac
     done
+
+
 }

 compile_object() {
@@ -344,6 +347,9 @@ for opt do
   --extra-cflags=*) QEMU_CFLAGS="$QEMU_CFLAGS $optarg"
                     EXTRA_CFLAGS="$optarg"
   ;;
+  --extra-cxxflags=*) QEMU_CXXFLAGS="$QEMU_CXXFLAGS $optarg"
+                      EXTRA_CXXFLAGS="$optarg"
+  ;;
   --extra-ldflags=*) LDFLAGS="$LDFLAGS $optarg"
                      EXTRA_LDFLAGS="$optarg"
   ;;
@@ -787,6 +793,8 @@ for opt do
   ;;
   --extra-cflags=*)
   ;;
+  --extra-cxxflags=*)
+  ;;
   --extra-ldflags=*)
   ;;
   --enable-debug-info)
@@ -1304,6 +1312,7 @@ Advanced options (experts only):
   --cxx=CXX                use C++ compiler CXX [$cxx]
   --objcc=OBJCC            use Objective-C compiler OBJCC [$objcc]
   --extra-cflags=CFLAGS    append extra C compiler flags QEMU_CFLAGS
+  --extra-cxxflags=CXXFLAGS append extra CXX compiler flags QEMU_CXXFLAGS
   --extra-ldflags=LDFLAGS  append extra linker flags LDFLAGS
   --make=MAKE              use specified make [$make]
   --install=INSTALL        use specified install [$install]
@@ -1489,37 +1498,6 @@ if test "$bogus_os" = "yes"; then
     error_exit "Unrecognized host OS $targetos"
 fi

-# Check that the C++ compiler exists and works with the C compiler
-if has $cxx; then
-    cat > $TMPC <<EOF
-int c_function(void);
-int main(void) { return c_function(); }
-EOF
-
-    compile_object
-
-    cat > $TMPCXX <<EOF
-extern "C" {
-   int c_function(void);
-}
-int c_function(void) { return 42; }
-EOF
-
-    update_cxxflags
-
-    if do_cxx $QEMU_CXXFLAGS -o $TMPE $TMPCXX $TMPO $LDFLAGS; then
-        # C++ compiler $cxx works ok with C compiler $cc
-        :
-    else
-        echo "C++ compiler $cxx does not work with C compiler $cc"
-        echo "Disabling C++ specific optional code"
-        cxx=
-    fi
-else
-    echo "No C++ compiler available; disabling C++ specific optional code"
-    cxx=
-fi
-
 gcc_flags="-Wold-style-declaration -Wold-style-definition -Wtype-limits"
 gcc_flags="-Wformat-security -Wformat-y2k -Winit-self
-Wignored-qualifiers $gcc_flags"
 gcc_flags="-Wno-missing-include-dirs -Wempty-body -Wnested-externs $gcc_flags"
@@ -5063,6 +5041,38 @@ EOF
   fi
 fi

+# Check that the C++ compiler exists and works with the C compiler.
+# All the QEMU_CXXFLAGS are based on QEMU_CFLAGS. Keep this at the
end to don't miss any other that could be added.
+if has $cxx; then
+    cat > $TMPC <<EOF
+int c_function(void);
+int main(void) { return c_function(); }
+EOF
+
+    compile_object
+
+    cat > $TMPCXX <<EOF
+extern "C" {
+   int c_function(void);
+}
+int c_function(void) { return 42; }
+EOF
+
+    update_cxxflags
+
+    if do_cxx $QEMU_CXXFLAGS -o $TMPE $TMPCXX $TMPO $LDFLAGS; then
+        # C++ compiler $cxx works ok with C compiler $cc
+        :
+    else
+        echo "C++ compiler $cxx does not work with C compiler $cc"
+        echo "Disabling C++ specific optional code"
+        cxx=
+    fi
+else
+    echo "No C++ compiler available; disabling C++ specific optional code"
+    cxx=
+fi
+
 echo_version() {
     if test "$1" = "yes" ; then
         echo "($2)"
@@ -5268,6 +5278,7 @@ if test "$mingw32" = "no" ; then
 fi
 echo "qemu_helperdir=$libexecdir" >> $config_host_mak
 echo "extra_cflags=$EXTRA_CFLAGS" >> $config_host_mak
+echo "extra_cxxflags=$EXTRA_CXXFLAGS" >> $config_host_mak
 echo "extra_ldflags=$EXTRA_LDFLAGS" >> $config_host_mak
 echo "qemu_localedir=$qemu_localedir" >> $config_host_mak
 echo "libs_softmmu=$libs_softmmu" >> $config_host_mak
@@ -5906,6 +5917,7 @@ echo "WINDRES=$windres" >> $config_host_mak
 echo "CFLAGS=$CFLAGS" >> $config_host_mak
 echo "CFLAGS_NOPIE=$CFLAGS_NOPIE" >> $config_host_mak
 echo "QEMU_CFLAGS=$QEMU_CFLAGS" >> $config_host_mak
+echo "QEMU_CXXFLAGS=$QEMU_CXXFLAGS" >> $config_host_mak
 echo "QEMU_INCLUDES=$QEMU_INCLUDES" >> $config_host_mak
 if test "$sparse" = "yes" ; then
   echo "CC           := REAL_CC=\"\$(CC)\" cgcc"       >> $config_host_mak
diff --git a/disas/libvixl/Makefile.objs b/disas/libvixl/Makefile.objs
index bbe7695..dbf7def 100644
--- a/disas/libvixl/Makefile.objs
+++ b/disas/libvixl/Makefile.objs
@@ -6,6 +6,6 @@ libvixl_OBJS = vixl/utils.o \

 # The -Wno-sign-compare is needed only for gcc 4.6, which complains about
 # some signed-unsigned equality comparisons which later gcc versions do not.
-$(addprefix $(obj)/,$(libvixl_OBJS)): QEMU_CFLAGS :=
-I$(SRC_PATH)/disas/libvixl $(QEMU_CFLAGS) -Wno-sign-compare
+$(addprefix $(obj)/,$(libvixl_OBJS)): QEMU_CXXFLAGS :=
-I$(SRC_PATH)/disas/libvixl $(QEMU_CXXFLAGS) -Wno-sign-compare

 common-obj-$(CONFIG_ARM_A64_DIS) += $(libvixl_OBJS)
diff --git a/rules.mak b/rules.mak
index 1c0eabb..2a2fb72 100644
--- a/rules.mak
+++ b/rules.mak
@@ -20,9 +20,6 @@ MAKEFLAGS += -rR
 %.mak:
 clean-target:

-# Flags for C++ compilation
-QEMU_CXXFLAGS = -D__STDC_LIMIT_MACROS $(filter-out
-Wstrict-prototypes -Wmissing-prototypes -Wnested-externs
-Wold-style-declaration -Wold-style-definition -Wredundant-decls,
$(QEMU_CFLAGS))
-
 # Flags for dependency generation
 QEMU_DGFLAGS += -MMD -MP -MT $@ -MF $(@D)/$(*F).d


Bruno

Re: [Qemu-devel] [PATCH] split c and cxx extra flags

[Bruno Dominguez]

Adding Peter Maydell in the cc and removing Claudio Fontana (It fails
sending to that address)

Bruno.

2017-06-02 14:07 GMT+01:00 Bruno Dominguez <bru.dominguez@gmail.com>:
> There was no possibility to add specific cxx flags using the configure
> file. So A new entrance has been created to support it.
>
> Duplication of information in configure and rules.mak. Taking
> QEMU_CFLAGS and add them to QEMU_CXXFLAGS, now the value of
> QEMU_CXXFLAGS is stored in config-host.mak, so there is no need for
> it.
>
> The makefile for libvixl was adding flags for QEMU_CXXFLAGS in
> QEMU_CFLAGS because of the addition in rules.mak. That was removed, so
> adding them where it should be.
>
> -----
> Signed-off-by: Bruno Dominguez <bru.dominguez@gmail.com>
> -----
>
> diff --git a/configure b/configure
> index 0586ec9..2fff3cc 100755
> --- a/configure
> +++ b/configure
> @@ -91,7 +91,8 @@ update_cxxflags() {
>      # Set QEMU_CXXFLAGS from QEMU_CFLAGS by filtering out those
>      # options which some versions of GCC's C++ compiler complain about
>      # because they only make sense for C programs.
> -    QEMU_CXXFLAGS=
> +    QEMU_CXXFLAGS="$QEMU_CXXFLAGS -D__STDC_LIMIT_MACROS"
> +
>      for arg in $QEMU_CFLAGS; do
>          case $arg in
>              -Wstrict-prototypes|-Wmissing-prototypes|-Wnested-externs|\
> @@ -102,6 +103,8 @@ update_cxxflags() {
>                  ;;
>          esac
>      done
> +
> +
>  }
>
>  compile_object() {
> @@ -344,6 +347,9 @@ for opt do
>    --extra-cflags=*) QEMU_CFLAGS="$QEMU_CFLAGS $optarg"
>                      EXTRA_CFLAGS="$optarg"
>    ;;
> +  --extra-cxxflags=*) QEMU_CXXFLAGS="$QEMU_CXXFLAGS $optarg"
> +                      EXTRA_CXXFLAGS="$optarg"
> +  ;;
>    --extra-ldflags=*) LDFLAGS="$LDFLAGS $optarg"
>                       EXTRA_LDFLAGS="$optarg"
>    ;;
> @@ -787,6 +793,8 @@ for opt do
>    ;;
>    --extra-cflags=*)
>    ;;
> +  --extra-cxxflags=*)
> +  ;;
>    --extra-ldflags=*)
>    ;;
>    --enable-debug-info)
> @@ -1304,6 +1312,7 @@ Advanced options (experts only):
>    --cxx=CXX                use C++ compiler CXX [$cxx]
>    --objcc=OBJCC            use Objective-C compiler OBJCC [$objcc]
>    --extra-cflags=CFLAGS    append extra C compiler flags QEMU_CFLAGS
> +  --extra-cxxflags=CXXFLAGS append extra CXX compiler flags QEMU_CXXFLAGS
>    --extra-ldflags=LDFLAGS  append extra linker flags LDFLAGS
>    --make=MAKE              use specified make [$make]
>    --install=INSTALL        use specified install [$install]
> @@ -1489,37 +1498,6 @@ if test "$bogus_os" = "yes"; then
>      error_exit "Unrecognized host OS $targetos"
>  fi
>
> -# Check that the C++ compiler exists and works with the C compiler
> -if has $cxx; then
> -    cat > $TMPC <<EOF
> -int c_function(void);
> -int main(void) { return c_function(); }
> -EOF
> -
> -    compile_object
> -
> -    cat > $TMPCXX <<EOF
> -extern "C" {
> -   int c_function(void);
> -}
> -int c_function(void) { return 42; }
> -EOF
> -
> -    update_cxxflags
> -
> -    if do_cxx $QEMU_CXXFLAGS -o $TMPE $TMPCXX $TMPO $LDFLAGS; then
> -        # C++ compiler $cxx works ok with C compiler $cc
> -        :
> -    else
> -        echo "C++ compiler $cxx does not work with C compiler $cc"
> -        echo "Disabling C++ specific optional code"
> -        cxx=
> -    fi
> -else
> -    echo "No C++ compiler available; disabling C++ specific optional code"
> -    cxx=
> -fi
> -
>  gcc_flags="-Wold-style-declaration -Wold-style-definition -Wtype-limits"
>  gcc_flags="-Wformat-security -Wformat-y2k -Winit-self
> -Wignored-qualifiers $gcc_flags"
>  gcc_flags="-Wno-missing-include-dirs -Wempty-body -Wnested-externs $gcc_flags"
> @@ -5063,6 +5041,38 @@ EOF
>    fi
>  fi
>
> +# Check that the C++ compiler exists and works with the C compiler.
> +# All the QEMU_CXXFLAGS are based on QEMU_CFLAGS. Keep this at the
> end to don't miss any other that could be added.
> +if has $cxx; then
> +    cat > $TMPC <<EOF
> +int c_function(void);
> +int main(void) { return c_function(); }
> +EOF
> +
> +    compile_object
> +
> +    cat > $TMPCXX <<EOF
> +extern "C" {
> +   int c_function(void);
> +}
> +int c_function(void) { return 42; }
> +EOF
> +
> +    update_cxxflags
> +
> +    if do_cxx $QEMU_CXXFLAGS -o $TMPE $TMPCXX $TMPO $LDFLAGS; then
> +        # C++ compiler $cxx works ok with C compiler $cc
> +        :
> +    else
> +        echo "C++ compiler $cxx does not work with C compiler $cc"
> +        echo "Disabling C++ specific optional code"
> +        cxx=
> +    fi
> +else
> +    echo "No C++ compiler available; disabling C++ specific optional code"
> +    cxx=
> +fi
> +
>  echo_version() {
>      if test "$1" = "yes" ; then
>          echo "($2)"
> @@ -5268,6 +5278,7 @@ if test "$mingw32" = "no" ; then
>  fi
>  echo "qemu_helperdir=$libexecdir" >> $config_host_mak
>  echo "extra_cflags=$EXTRA_CFLAGS" >> $config_host_mak
> +echo "extra_cxxflags=$EXTRA_CXXFLAGS" >> $config_host_mak
>  echo "extra_ldflags=$EXTRA_LDFLAGS" >> $config_host_mak
>  echo "qemu_localedir=$qemu_localedir" >> $config_host_mak
>  echo "libs_softmmu=$libs_softmmu" >> $config_host_mak
> @@ -5906,6 +5917,7 @@ echo "WINDRES=$windres" >> $config_host_mak
>  echo "CFLAGS=$CFLAGS" >> $config_host_mak
>  echo "CFLAGS_NOPIE=$CFLAGS_NOPIE" >> $config_host_mak
>  echo "QEMU_CFLAGS=$QEMU_CFLAGS" >> $config_host_mak
> +echo "QEMU_CXXFLAGS=$QEMU_CXXFLAGS" >> $config_host_mak
>  echo "QEMU_INCLUDES=$QEMU_INCLUDES" >> $config_host_mak
>  if test "$sparse" = "yes" ; then
>    echo "CC           := REAL_CC=\"\$(CC)\" cgcc"       >> $config_host_mak
> diff --git a/disas/libvixl/Makefile.objs b/disas/libvixl/Makefile.objs
> index bbe7695..dbf7def 100644
> --- a/disas/libvixl/Makefile.objs
> +++ b/disas/libvixl/Makefile.objs
> @@ -6,6 +6,6 @@ libvixl_OBJS = vixl/utils.o \
>
>  # The -Wno-sign-compare is needed only for gcc 4.6, which complains about
>  # some signed-unsigned equality comparisons which later gcc versions do not.
> -$(addprefix $(obj)/,$(libvixl_OBJS)): QEMU_CFLAGS :=
> -I$(SRC_PATH)/disas/libvixl $(QEMU_CFLAGS) -Wno-sign-compare
> +$(addprefix $(obj)/,$(libvixl_OBJS)): QEMU_CXXFLAGS :=
> -I$(SRC_PATH)/disas/libvixl $(QEMU_CXXFLAGS) -Wno-sign-compare
>
>  common-obj-$(CONFIG_ARM_A64_DIS) += $(libvixl_OBJS)
> diff --git a/rules.mak b/rules.mak
> index 1c0eabb..2a2fb72 100644
> --- a/rules.mak
> +++ b/rules.mak
> @@ -20,9 +20,6 @@ MAKEFLAGS += -rR
>  %.mak:
>  clean-target:
>
> -# Flags for C++ compilation
> -QEMU_CXXFLAGS = -D__STDC_LIMIT_MACROS $(filter-out
> -Wstrict-prototypes -Wmissing-prototypes -Wnested-externs
> -Wold-style-declaration -Wold-style-definition -Wredundant-decls,
> $(QEMU_CFLAGS))
> -
>  # Flags for dependency generation
>  QEMU_DGFLAGS += -MMD -MP -MT $@ -MF $(@D)/$(*F).d
>
>
> Bruno

Re: [Qemu-devel] [PATCH] split c and cxx extra flags

[Stefan Hajnoczi]

[-- Attachment #1: Type: text/plain, Size: 3091 bytes --]

On Fri, Jun 02, 2017 at 02:07:26PM +0100, Bruno Dominguez wrote:
> There was no possibility to add specific cxx flags using the configure
> file. So A new entrance has been created to support it.
> 
> Duplication of information in configure and rules.mak. Taking
> QEMU_CFLAGS and add them to QEMU_CXXFLAGS, now the value of
> QEMU_CXXFLAGS is stored in config-host.mak, so there is no need for
> it.
> 
> The makefile for libvixl was adding flags for QEMU_CXXFLAGS in
> QEMU_CFLAGS because of the addition in rules.mak. That was removed, so
> adding them where it should be.
> 
> -----
> Signed-off-by: Bruno Dominguez <bru.dominguez@gmail.com>
> -----

Please follow the code submission guidelines:
http://wiki.qemu.org/Contribute/SubmitAPatch

 * The commit message (email subject) should have a prefix describing
   the affected component.  Use "git log ./configure" for inspiration.
   I suggest the following:

     configure: split c and cxx extra flags

 * Use git-format-patch(1) so that your patch applies cleanly.  Your
   email has:

   ----
   Signed-off-by: ...
   ----

   This is not the format recognized by tools.  Instead the
   Signed-off-by: should be part of the commit description (no '----')
   and then a line with just three hyphens ('---') denotes the end of
   the commit description:

   Signed-off-by: ...
   ---

 * The email must not be line-wrapped since that breaks the patch.  If
   you use git-send-email(1) to submit patches then this is taken care
   of automatically.

> @@ -1304,6 +1312,7 @@ Advanced options (experts only):
>    --cxx=CXX                use C++ compiler CXX [$cxx]
>    --objcc=OBJCC            use Objective-C compiler OBJCC [$objcc]
>    --extra-cflags=CFLAGS    append extra C compiler flags QEMU_CFLAGS
> +  --extra-cxxflags=CXXFLAGS append extra CXX compiler flags QEMU_CXXFLAGS

For consistency with the --cxx= option description:

s/CXX compiler/C++ compiler/

> @@ -1489,37 +1498,6 @@ if test "$bogus_os" = "yes"; then
>      error_exit "Unrecognized host OS $targetos"
>  fi
> 
> -# Check that the C++ compiler exists and works with the C compiler
> -if has $cxx; then
> -    cat > $TMPC <<EOF
> -int c_function(void);
> -int main(void) { return c_function(); }
> -EOF
> -
> -    compile_object
> -
> -    cat > $TMPCXX <<EOF
> -extern "C" {
> -   int c_function(void);
> -}
> -int c_function(void) { return 42; }
> -EOF
> -
> -    update_cxxflags
> -
> -    if do_cxx $QEMU_CXXFLAGS -o $TMPE $TMPCXX $TMPO $LDFLAGS; then
> -        # C++ compiler $cxx works ok with C compiler $cc
> -        :
> -    else
> -        echo "C++ compiler $cxx does not work with C compiler $cc"
> -        echo "Disabling C++ specific optional code"
> -        cxx=
> -    fi
> -else
> -    echo "No C++ compiler available; disabling C++ specific optional code"
> -    cxx=
> -fi
> -

Why move this code?

> 
> Bruno
> 

This signature will break tools that apply the patch.  It's easiest to
use git-send-email(1) to avoid problems like this.

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 455 bytes --]

Re: [Qemu-devel] [PATCH] split c and cxx extra flags

[Bruno Dominguez]

2017-06-06 10:28 GMT+01:00 Stefan Hajnoczi <stefanha@gmail.com>:
> On Fri, Jun 02, 2017 at 02:07:26PM +0100, Bruno Dominguez wrote:
>> There was no possibility to add specific cxx flags using the configure
>> file. So A new entrance has been created to support it.
>>
>> Duplication of information in configure and rules.mak. Taking
>> QEMU_CFLAGS and add them to QEMU_CXXFLAGS, now the value of
>> QEMU_CXXFLAGS is stored in config-host.mak, so there is no need for
>> it.
>>
>> The makefile for libvixl was adding flags for QEMU_CXXFLAGS in
>> QEMU_CFLAGS because of the addition in rules.mak. That was removed, so
>> adding them where it should be.
>>
>> -----
>> Signed-off-by: Bruno Dominguez <bru.dominguez@gmail.com>
>> -----
>
> Please follow the code submission guidelines:
> http://wiki.qemu.org/Contribute/SubmitAPatch
>
>  * The commit message (email subject) should have a prefix describing
>    the affected component.  Use "git log ./configure" for inspiration.
>    I suggest the following:
>
>      configure: split c and cxx extra flags
>
>  * Use git-format-patch(1) so that your patch applies cleanly.  Your
>    email has:
>
>    ----
>    Signed-off-by: ...
>    ----
>
>    This is not the format recognized by tools.  Instead the
>    Signed-off-by: should be part of the commit description (no '----')
>    and then a line with just three hyphens ('---') denotes the end of
>    the commit description:
>
>    Signed-off-by: ...
>    ---
>
>  * The email must not be line-wrapped since that breaks the patch.  If
>    you use git-send-email(1) to submit patches then this is taken care
>    of automatically.
>

ok, will give it another go.

>> @@ -1304,6 +1312,7 @@ Advanced options (experts only):
>>    --cxx=CXX                use C++ compiler CXX [$cxx]
>>    --objcc=OBJCC            use Objective-C compiler OBJCC [$objcc]
>>    --extra-cflags=CFLAGS    append extra C compiler flags QEMU_CFLAGS
>> +  --extra-cxxflags=CXXFLAGS append extra CXX compiler flags QEMU_CXXFLAGS
>
> For consistency with the --cxx= option description:
>
> s/CXX compiler/C++ compiler/
>

will do.

>> @@ -1489,37 +1498,6 @@ if test "$bogus_os" = "yes"; then
>>      error_exit "Unrecognized host OS $targetos"
>>  fi
>>
>> -# Check that the C++ compiler exists and works with the C compiler
>> -if has $cxx; then
>> -    cat > $TMPC <<EOF
>> -int c_function(void);
>> -int main(void) { return c_function(); }
>> -EOF
>> -
>> -    compile_object
>> -
>> -    cat > $TMPCXX <<EOF
>> -extern "C" {
>> -   int c_function(void);
>> -}
>> -int c_function(void) { return 42; }
>> -EOF
>> -
>> -    update_cxxflags
>> -
>> -    if do_cxx $QEMU_CXXFLAGS -o $TMPE $TMPCXX $TMPO $LDFLAGS; then
>> -        # C++ compiler $cxx works ok with C compiler $cc
>> -        :
>> -    else
>> -        echo "C++ compiler $cxx does not work with C compiler $cc"
>> -        echo "Disabling C++ specific optional code"
>> -        cxx=
>> -    fi
>> -else
>> -    echo "No C++ compiler available; disabling C++ specific optional code"
>> -    cxx=
>> -fi
>> -
>
> Why move this code?
>

the configure file adds "-fPIE -DPIE" to QEMU_CFLAGS around line 1570.
Where QEMU_CXXFLAGS is placed is not taken it, hence this flag is not
tested with the c++ compiler and breaks the build later on for not
existing. Because QEMU_CXXFLAGS was reassigned again in rules.mak this
was hidden.

Re: [Qemu-devel] [PATCH] split c and cxx extra flags

[Stefan Hajnoczi]

On Tue, Jun 6, 2017 at 10:45 AM, Bruno Dominguez
<bru.dominguez@gmail.com> wrote:
> 2017-06-06 10:28 GMT+01:00 Stefan Hajnoczi <stefanha@gmail.com>:
>> On Fri, Jun 02, 2017 at 02:07:26PM +0100, Bruno Dominguez wrote:
>>> @@ -1489,37 +1498,6 @@ if test "$bogus_os" = "yes"; then
>>>      error_exit "Unrecognized host OS $targetos"
>>>  fi
>>>
>>> -# Check that the C++ compiler exists and works with the C compiler
>>> -if has $cxx; then
>>> -    cat > $TMPC <<EOF
>>> -int c_function(void);
>>> -int main(void) { return c_function(); }
>>> -EOF
>>> -
>>> -    compile_object
>>> -
>>> -    cat > $TMPCXX <<EOF
>>> -extern "C" {
>>> -   int c_function(void);
>>> -}
>>> -int c_function(void) { return 42; }
>>> -EOF
>>> -
>>> -    update_cxxflags
>>> -
>>> -    if do_cxx $QEMU_CXXFLAGS -o $TMPE $TMPCXX $TMPO $LDFLAGS; then
>>> -        # C++ compiler $cxx works ok with C compiler $cc
>>> -        :
>>> -    else
>>> -        echo "C++ compiler $cxx does not work with C compiler $cc"
>>> -        echo "Disabling C++ specific optional code"
>>> -        cxx=
>>> -    fi
>>> -else
>>> -    echo "No C++ compiler available; disabling C++ specific optional code"
>>> -    cxx=
>>> -fi
>>> -
>>
>> Why move this code?
>>
>
> the configure file adds "-fPIE -DPIE" to QEMU_CFLAGS around line 1570.
> Where QEMU_CXXFLAGS is placed is not taken it, hence this flag is not
> tested with the c++ compiler and breaks the build later on for not
> existing. Because QEMU_CXXFLAGS was reassigned again in rules.mak this
> was hidden.

Thanks for explaining.

Stefan

Re: [Qemu-devel] [PATCH] split c and cxx extra flags

[Bruno Dominguez]

sending again the patch with the correct format and:

1. Matching --extra-cxxflags description with --cxx
2. Removing some extra spaces indicated by checkpatch script.

Signed-off-by: Bruno Dominguez <bru.dominguez@gmail.com>
---
 configure                   | 74 +++++++++++++++++++++++++--------------------
 disas/libvixl/Makefile.objs |  2 +-
 rules.mak                   |  3 --
 3 files changed, 43 insertions(+), 36 deletions(-)

diff --git a/configure b/configure
index 0586ec9..4ab0d0f 100755
--- a/configure
+++ b/configure
@@ -91,7 +91,8 @@ update_cxxflags() {
     # Set QEMU_CXXFLAGS from QEMU_CFLAGS by filtering out those
     # options which some versions of GCC's C++ compiler complain about
     # because they only make sense for C programs.
-    QEMU_CXXFLAGS=
+    QEMU_CXXFLAGS="$QEMU_CXXFLAGS -D__STDC_LIMIT_MACROS"
+
     for arg in $QEMU_CFLAGS; do
         case $arg in
             -Wstrict-prototypes|-Wmissing-prototypes|-Wnested-externs|\
@@ -344,6 +345,9 @@ for opt do
   --extra-cflags=*) QEMU_CFLAGS="$QEMU_CFLAGS $optarg"
                     EXTRA_CFLAGS="$optarg"
   ;;
+  --extra-cxxflags=*) QEMU_CXXFLAGS="$QEMU_CXXFLAGS $optarg"
+                      EXTRA_CXXFLAGS="$optarg"
+  ;;
   --extra-ldflags=*) LDFLAGS="$LDFLAGS $optarg"
                      EXTRA_LDFLAGS="$optarg"
   ;;
@@ -787,6 +791,8 @@ for opt do
   ;;
   --extra-cflags=*)
   ;;
+  --extra-cxxflags=*)
+  ;;
   --extra-ldflags=*)
   ;;
   --enable-debug-info)
@@ -1304,6 +1310,7 @@ Advanced options (experts only):
   --cxx=CXX                use C++ compiler CXX [$cxx]
   --objcc=OBJCC            use Objective-C compiler OBJCC [$objcc]
   --extra-cflags=CFLAGS    append extra C compiler flags QEMU_CFLAGS
+  --extra-cxxflags=CXXFLAGS append extra C++ compiler flags QEMU_CXXFLAGS
   --extra-ldflags=LDFLAGS  append extra linker flags LDFLAGS
   --make=MAKE              use specified make [$make]
   --install=INSTALL        use specified install [$install]
@@ -1489,37 +1496,6 @@ if test "$bogus_os" = "yes"; then
     error_exit "Unrecognized host OS $targetos"
 fi

-# Check that the C++ compiler exists and works with the C compiler
-if has $cxx; then
-    cat > $TMPC <<EOF
-int c_function(void);
-int main(void) { return c_function(); }
-EOF
-
-    compile_object
-
-    cat > $TMPCXX <<EOF
-extern "C" {
-   int c_function(void);
-}
-int c_function(void) { return 42; }
-EOF
-
-    update_cxxflags
-
-    if do_cxx $QEMU_CXXFLAGS -o $TMPE $TMPCXX $TMPO $LDFLAGS; then
-        # C++ compiler $cxx works ok with C compiler $cc
-        :
-    else
-        echo "C++ compiler $cxx does not work with C compiler $cc"
-        echo "Disabling C++ specific optional code"
-        cxx=
-    fi
-else
-    echo "No C++ compiler available; disabling C++ specific optional code"
-    cxx=
-fi
-
 gcc_flags="-Wold-style-declaration -Wold-style-definition -Wtype-limits"
 gcc_flags="-Wformat-security -Wformat-y2k -Winit-self
-Wignored-qualifiers $gcc_flags"
 gcc_flags="-Wno-missing-include-dirs -Wempty-body -Wnested-externs $gcc_flags"
@@ -5063,6 +5039,38 @@ EOF
   fi
 fi

+# Check that the C++ compiler exists and works with the C compiler.
+# All the QEMU_CXXFLAGS are based on QEMU_CFLAGS. Keep this at the
end to don't miss any other that could be added.
+if has $cxx; then
+    cat > $TMPC <<EOF
+int c_function(void);
+int main(void) { return c_function(); }
+EOF
+
+    compile_object
+
+    cat > $TMPCXX <<EOF
+extern "C" {
+   int c_function(void);
+}
+int c_function(void) { return 42; }
+EOF
+
+    update_cxxflags
+
+    if do_cxx $QEMU_CXXFLAGS -o $TMPE $TMPCXX $TMPO $LDFLAGS; then
+        # C++ compiler $cxx works ok with C compiler $cc
+        :
+    else
+        echo "C++ compiler $cxx does not work with C compiler $cc"
+        echo "Disabling C++ specific optional code"
+        cxx=
+    fi
+else
+    echo "No C++ compiler available; disabling C++ specific optional code"
+    cxx=
+fi
+
 echo_version() {
     if test "$1" = "yes" ; then
         echo "($2)"
@@ -5268,6 +5276,7 @@ if test "$mingw32" = "no" ; then
 fi
 echo "qemu_helperdir=$libexecdir" >> $config_host_mak
 echo "extra_cflags=$EXTRA_CFLAGS" >> $config_host_mak
+echo "extra_cxxflags=$EXTRA_CXXFLAGS" >> $config_host_mak
 echo "extra_ldflags=$EXTRA_LDFLAGS" >> $config_host_mak
 echo "qemu_localedir=$qemu_localedir" >> $config_host_mak
 echo "libs_softmmu=$libs_softmmu" >> $config_host_mak
@@ -5906,6 +5915,7 @@ echo "WINDRES=$windres" >> $config_host_mak
 echo "CFLAGS=$CFLAGS" >> $config_host_mak
 echo "CFLAGS_NOPIE=$CFLAGS_NOPIE" >> $config_host_mak
 echo "QEMU_CFLAGS=$QEMU_CFLAGS" >> $config_host_mak
+echo "QEMU_CXXFLAGS=$QEMU_CXXFLAGS" >> $config_host_mak
 echo "QEMU_INCLUDES=$QEMU_INCLUDES" >> $config_host_mak
 if test "$sparse" = "yes" ; then
   echo "CC           := REAL_CC=\"\$(CC)\" cgcc"       >> $config_host_mak
diff --git a/disas/libvixl/Makefile.objs b/disas/libvixl/Makefile.objs
index bbe7695..dbf7def 100644
--- a/disas/libvixl/Makefile.objs
+++ b/disas/libvixl/Makefile.objs
@@ -6,6 +6,6 @@ libvixl_OBJS = vixl/utils.o \

 # The -Wno-sign-compare is needed only for gcc 4.6, which complains about
 # some signed-unsigned equality comparisons which later gcc versions do not.
-$(addprefix $(obj)/,$(libvixl_OBJS)): QEMU_CFLAGS :=
-I$(SRC_PATH)/disas/libvixl $(QEMU_CFLAGS) -Wno-sign-compare
+$(addprefix $(obj)/,$(libvixl_OBJS)): QEMU_CXXFLAGS :=
-I$(SRC_PATH)/disas/libvixl $(QEMU_CXXFLAGS) -Wno-sign-compare

 common-obj-$(CONFIG_ARM_A64_DIS) += $(libvixl_OBJS)
diff --git a/rules.mak b/rules.mak
index 1c0eabb..2a2fb72 100644
--- a/rules.mak
+++ b/rules.mak
@@ -20,9 +20,6 @@ MAKEFLAGS += -rR
 %.mak:
 clean-target:

-# Flags for C++ compilation
-QEMU_CXXFLAGS = -D__STDC_LIMIT_MACROS $(filter-out
-Wstrict-prototypes -Wmissing-prototypes -Wnested-externs
-Wold-style-declaration -Wold-style-definition -Wredundant-decls,
$(QEMU_CFLAGS))
-
 # Flags for dependency generation
 QEMU_DGFLAGS += -MMD -MP -MT $@ -MF $(@D)/$(*F).d

--
1.9.1

Re: [Qemu-devel] [PATCH] split c and cxx extra flags

[Stefan Hajnoczi]

On Tue, Jun 6, 2017 at 1:20 PM, Bruno Dominguez <bru.dominguez@gmail.com> wrote:
> sending again the patch with the correct format and:
>
> 1. Matching --extra-cxxflags description with --cxx
> 2. Removing some extra spaces indicated by checkpatch script.

The code looks fine to me:
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

A few more points about patch submission:

All email body text above '---' is the commit description that is
included in the git log.  Therefore the commit description should only
contain information that is useful in the version history, like the
rationale for this commit.

Please put changelog information below '---' so it does not become
part of the git log.  Once the patch has been merged it's not useful
to know that you're "sending again the patch with the correct format
and:" and so on.

The submission guidelines page says "send each new revision as a new
top-level thread, rather than burying it in-reply-to an earlier
revision, as many reviewers are not looking inside deep threads for
new patches".

There are tools that make it easy to send and manage patch series.
That way you don't have to invoke git-format-patch/git-send-email and
perform manual steps.  The tool I use is git-publish:
https://github.com/stefanha/git-publish

Putting this all together, please send a new top-level email like this:

Subject: [PATCH v2] configure: split c and cxx extra flags

There was no possibility to add specific cxx flags using the configure
file. So A new entrance has been created to support it.

Duplication of information in configure and rules.mak. Taking
QEMU_CFLAGS and add them to QEMU_CXXFLAGS, now the value of
QEMU_CXXFLAGS is stored in config-host.mak, so there is no need for
it.

The makefile for libvixl was adding flags for QEMU_CXXFLAGS in
QEMU_CFLAGS because of the addition in rules.mak. That was removed, so
adding them where it should be.

Signed-off-by: Bruno Dominguez <bru.dominguez@gmail.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
v2:
 * Matching --extra-cxxflags description with --cxx
 * Removing some extra spaces indicated by checkpatch script
 * Fixed patch format

...

Re: [Qemu-devel] [PATCH] split c and cxx extra flags

[Bruno Dominguez]

ok, thanks for the clarification.

2017-06-06 13:38 GMT+01:00 Stefan Hajnoczi <stefanha@gmail.com>:
> On Tue, Jun 6, 2017 at 1:20 PM, Bruno Dominguez <bru.dominguez@gmail.com> wrote:
>> sending again the patch with the correct format and:
>>
>> 1. Matching --extra-cxxflags description with --cxx
>> 2. Removing some extra spaces indicated by checkpatch script.
>
> The code looks fine to me:
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
>
> A few more points about patch submission:
>
> All email body text above '---' is the commit description that is
> included in the git log.  Therefore the commit description should only
> contain information that is useful in the version history, like the
> rationale for this commit.
>
> Please put changelog information below '---' so it does not become
> part of the git log.  Once the patch has been merged it's not useful
> to know that you're "sending again the patch with the correct format
> and:" and so on.
>
> The submission guidelines page says "send each new revision as a new
> top-level thread, rather than burying it in-reply-to an earlier
> revision, as many reviewers are not looking inside deep threads for
> new patches".
>
> There are tools that make it easy to send and manage patch series.
> That way you don't have to invoke git-format-patch/git-send-email and
> perform manual steps.  The tool I use is git-publish:
> https://github.com/stefanha/git-publish
>
> Putting this all together, please send a new top-level email like this:
>
> Subject: [PATCH v2] configure: split c and cxx extra flags
>
> There was no possibility to add specific cxx flags using the configure
> file. So A new entrance has been created to support it.
>
> Duplication of information in configure and rules.mak. Taking
> QEMU_CFLAGS and add them to QEMU_CXXFLAGS, now the value of
> QEMU_CXXFLAGS is stored in config-host.mak, so there is no need for
> it.
>
> The makefile for libvixl was adding flags for QEMU_CXXFLAGS in
> QEMU_CFLAGS because of the addition in rules.mak. That was removed, so
> adding them where it should be.
>
> Signed-off-by: Bruno Dominguez <bru.dominguez@gmail.com>
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
> v2:
>  * Matching --extra-cxxflags description with --cxx
>  * Removing some extra spaces indicated by checkpatch script
>  * Fixed patch format
>
> ...