Re: [Qemu-devel] [PATCH v7 01/10] configure: Support configuring C++ compiler

[Michael Roth <mdroth@linux.vnet.ibm.com>]

Quoting Tomoki Sekiyama (2013-07-15 11:20:29)
> Add configuration for C++ compiler in configure and Makefiles.
> The C++ compiler is choosed as following:
>  - ${CXX}, if it is specified.
>  - ${cross_prefix}g++, if ${cross_prefix} is specified.
>  - Otherwise, c++ is used.
> 
> Currently, usage of C++ language is only for access to Windows VSS
> using COM+ services in qemu-guest-agent for Windows.
> 
> Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama@hds.com>
> Reviewed-by: Laszlo Ersek <lersek@redhat.com>
> ---
>  configure |   13 +++++++++++++
>  rules.mak |    9 ++++++++-
>  2 files changed, 21 insertions(+), 1 deletion(-)
> 
> diff --git a/configure b/configure
> index cb0f870..6923b65 100755
> --- a/configure
> +++ b/configure
> @@ -251,6 +251,8 @@ for opt do
>    ;;
>    --cc=*) CC="$optarg"
>    ;;
> +  --cxx=*) CXX="$optarg"
> +  ;;
>    --source-path=*) source_path="$optarg"
>    ;;
>    --cpu=*) cpu="$optarg"
> @@ -281,6 +283,12 @@ else
>    cc="${CC-${cross_prefix}gcc}"
>  fi
> 
> +if test -z "${CXX}${cross_prefix}"; then
> +  cxx="c++"
> +else
> +  cxx="${CXX-${cross_prefix}g++}"
> +fi
> +
>  ar="${AR-${cross_prefix}ar}"
>  as="${AS-${cross_prefix}as}"
>  cpp="${CPP-$cc -E}"
> @@ -621,6 +629,8 @@ for opt do
>    ;;
>    --host-cc=*) host_cc="$optarg"
>    ;;
> +  --cxx=*) cxx="$optarg"
> +  ;;

Since we've already determined cxx in the first pass (overriding other
defaults --cxx argument if it's present), I think re-assigning here
is unecessary.

Otherwise looks good.

>    --objcc=*) objcc="$optarg"
>    ;;
>    --make=*) make="$optarg"
> @@ -1022,6 +1032,7 @@ echo "  --cross-prefix=PREFIX    use PREFIX for compile tools [$cross_prefix]"
>  echo "  --cc=CC                  use C compiler CC [$cc]"
>  echo "  --host-cc=CC             use C compiler CC [$host_cc] for code run at"
>  echo "                           build time"
> +echo "  --cxx=CXX                use C++ compiler CXX [$cxx]"
>  echo "  --objcc=OBJCC            use Objective-C compiler OBJCC [$objcc]"
>  echo "  --extra-cflags=CFLAGS    append extra C compiler flags QEMU_CFLAGS"
>  echo "  --extra-ldflags=LDFLAGS  append extra linker flags LDFLAGS"
> @@ -3496,6 +3507,7 @@ fi
>  echo "Source path       $source_path"
>  echo "C compiler        $cc"
>  echo "Host C compiler   $host_cc"
> +echo "C++ compiler      $cxx"
>  echo "Objective-C compiler $objcc"
>  echo "CFLAGS            $CFLAGS"
>  echo "QEMU_CFLAGS       $QEMU_CFLAGS"
> @@ -4069,6 +4081,7 @@ echo "PYTHON=$python" >> $config_host_mak
>  echo "CC=$cc" >> $config_host_mak
>  echo "CC_I386=$cc_i386" >> $config_host_mak
>  echo "HOST_CC=$host_cc" >> $config_host_mak
> +echo "CXX=$cxx" >> $config_host_mak
>  echo "OBJCC=$objcc" >> $config_host_mak
>  echo "AR=$ar" >> $config_host_mak
>  echo "AS=$as" >> $config_host_mak
> diff --git a/rules.mak b/rules.mak
> index 4499745..abc2e84 100644
> --- a/rules.mak
> +++ b/rules.mak
> @@ -8,9 +8,13 @@ MAKEFLAGS += -rR
>  %.d:
>  %.h:
>  %.c:
> +%.cpp:
>  %.m:
>  %.mak:
> 
> +# 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
> 
> @@ -50,6 +54,9 @@ endif
>  %.o: %.asm
>         $(call quiet-command,$(AS) $(ASFLAGS) -o $@ $<,"  AS    $(TARGET_DIR)$@")
> 
> +%.o: %.cpp
> +       $(call quiet-command,$(CXX) $(QEMU_INCLUDES) $(QEMU_CXXFLAGS) $(QEMU_DGFLAGS) $(CFLAGS) -c -o $@ $<,"  CXX   $(TARGET_DIR)$@")
> +
>  %.o: %.m
>         $(call quiet-command,$(OBJCC) $(QEMU_INCLUDES) $(QEMU_CFLAGS) $(QEMU_DGFLAGS) $(CFLAGS) -c -o $@ $<,"  OBJC  $(TARGET_DIR)$@")
> 
> @@ -70,7 +77,7 @@ quiet-command = $(if $(V),$1,$(if $(2),@echo $2 && $1, @$1))
>  cc-option = $(if $(shell $(CC) $1 $2 -S -o /dev/null -xc /dev/null \
>                >/dev/null 2>&1 && echo OK), $2, $3)
> 
> -VPATH_SUFFIXES = %.c %.h %.S %.m %.mak %.texi %.sh %.rc
> +VPATH_SUFFIXES = %.c %.h %.S %.cpp %.m %.mak %.texi %.sh %.rc
>  set-vpath = $(if $1,$(foreach PATTERN,$(VPATH_SUFFIXES),$(eval vpath $(PATTERN) $1)))
> 
>  # find-in-path