Re: [Qemu-devel] [PATCH V9 5/8] libqblock build system

[Wenchao Xia <xiawenc@linux.vnet.ibm.com>]

于 2012-11-18 22:58, Paolo Bonzini 写道:
> Il 18/11/2012 14:06, Wenchao Xia ha scritto:
>> 于 2012-11-16 19:08, Paolo Bonzini 写道:
>>> Il 16/11/2012 11:12, Wenchao Xia ha scritto:
>>>>     Libqblock was placed in new directory ./libqblock, libtool will build
>>>> dynamic library there, source files of block layer remains in ./block.
>>>> So block related source code will generate 3 sets of binary, first is
>>>> old
>>>> ones used in qemu, second and third are non PIC and PIC ones in
>>>> ./libqblock.
>>>>     GCC compiler flag visibility=hidden was used with special macro,
>>>> to export
>>>> only symbols that was marked as PUBLIC.
>>>>     For testing, make check-libqblock will build binaries and execute
>>>> it, make
>>>> clean or make check-clean will delete generated binaries.
>>>>     By default this library will be built and tested, out of tree
>>>> building is
>>>> supported.
>>>>     Header files added in configure due to install-libqblock from out
>>>> of tree
>>>> build need these them.
>>>
>>> Use $(SRC_PATH) instead in the install rules.
>>>
>>    OK.
>>
>>>>
>>>> Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
>>>> ---
>>>>    .gitignore                        |    2 +
>>>>    Makefile                          |   12 ++++++-
>>>>    configure                         |    4 ++-
>>>>    libqblock/Makefile                |   72
>>>> +++++++++++++++++++++++++++++++++++++
>>>>    libqblock/libqblock.pc.in         |   13 +++++++
>>>>    tests/Makefile                    |   29 ++++++++++++++-
>>>>    tests/libqblock/libqblock-qcow2.c |    4 ++
>>>>    7 files changed, 133 insertions(+), 3 deletions(-)
>>>>    create mode 100644 libqblock/Makefile
>>>>    create mode 100644 libqblock/libqblock-error.c
>>>>    create mode 100644 libqblock/libqblock-error.h
>>>>    create mode 100644 libqblock/libqblock-types.h
>>>>    create mode 100644 libqblock/libqblock.c
>>>>    create mode 100644 libqblock/libqblock.h
>>>>    create mode 100644 libqblock/libqblock.pc.in
>>>>    create mode 100644 tests/libqblock/libqblock-qcow2.c
>>>>
>>>> diff --git a/.gitignore b/.gitignore
>>>> index bd6ba1c..76207fe 100644
>>>> --- a/.gitignore
>>>> +++ b/.gitignore
>>>> @@ -93,3 +93,5 @@ cscope.*
>>>>    tags
>>>>    TAGS
>>>>    *~
>>>> +tests/libqblock/check-*
>>>> +tests/libqblock/test_images
>>>> diff --git a/Makefile b/Makefile
>>>> index 2cde430..4b0755d 100644
>>>> --- a/Makefile
>>>> +++ b/Makefile
>>>> @@ -189,6 +189,16 @@ qemu-io$(EXESUF): qemu-io.o cmd.o $(tools-obj-y)
>>>> $(block-obj-y)
>>>>
>>>>    qemu-bridge-helper$(EXESUF): qemu-bridge-helper.o
>>>>
>>>> +######################################################################
>>>> +# Support building shared library libqblock
>>>> +libqblock.la:
>>>> +    $(call quiet-command,$(MAKE) $(SUBDIR_MAKEFLAGS) -C libqblock
>>>> V="$(V)" TARGET_DIR="$*/" libqblock.la,)
>>>> +
>>>> +install-libqblock:
>>>> +    $(call quiet-command,$(MAKE) $(SUBDIR_MAKEFLAGS) -C libqblock
>>>> V="$(V)" TARGET_DIR="$*/" install-libqblock,)
>>>
>>> Who calls install-libqblock?
>>>
>>    No one now, just provided an install rules similar to libcacard.
>
> Please call it from the install target (through a dependency).  Also
> remember to make these targets phony.
>
   right, phony is important, I forgot it before.

>
>>>> +#library objects
>>>> +libqblock-y=libqblock/libqblock.o libqblock/libqblock-error.o
>>>> +tools-obj-y =  $(oslib-obj-y) $(trace-obj-y) qemu-tool.o qemu-timer.o \
>>>> +       qemu-timer-common.o main-loop.o notify.o \
>>>> +       iohandler.o cutils.o iov.o async.o
>>>> +tools-obj-$(CONFIG_POSIX) += compatfd.o
>>>
>>> Are all of these really needed?  (In fact, after some of the recent
>>> changes none of these should be needed).
>>>
>>    OK, I'll try remove tools-objs.
>
> Or perhaps just trim it down.  Moving it to Makefile.objs is another
> idea, but please keep it as small as possible.
>
>
   OK.


>>>> +tests/libqblock/%.o: QEMU_CFLAGS:= $(subst -fPIE,-fPIC, $(QEMU_CFLAGS))
>>>> +tests/libqblock/%.o: QEMU_CFLAGS:= $(subst -DPIE,-DPIC, $(QEMU_CFLAGS))
>>>
>>> Why?
>>>
>>> A hint: if you have to do something that is not done anywhere else in
>>> the tree, do not do it.
>>>
>>    not sure whether PIE objs can be linked with dynamic library, let me
>> try remove it.
>
> They cannot be part of a dynamic library, but they sure can be linked
> with one.  QEMU itself is PIE and linked with SDL, gnutls, etc.
>
   Thanks, this extended my knowledge.

>>> Also, I'm not sure we need a completely separate subdirectory for one
>>> file only.  You can just use
>>>
>>> $(check-libqblock-y): QEMU_INCLUDES += ...
>>>
>>> Paolo
>>>
>>    A separate directory will allow more test cases come in easily,
>> I thought to added more test cases before.
>
> But you have one for now... :)
>
   OK.

> Paolo
>


-- 
Best Regards

Wenchao Xia