Re: [Qemu-devel] [RFC] Avoiding --whole-archive

["Andreas Färber" <andreas.faerber@web.de>]

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Am 29.11.2009 um 15:17 schrieb Andreas Färber:

> Am 14.06.2009 um 00:15 schrieb Andreas Färber:
>
>>>> Am 31.05.2009 um 12:15 schrieb Anthony Liguori:
>>>>
>>>>>>> Starting with this commit, qemu-system-sparc segfaults  
>>>>>>> immediately;
>>>>>>> you later fixed it in c833ab7351f2ebac46740380a81e34482e208dcc  
>>>>>>> (Fix
>>>>>>> segv when passing an unknown protocol) to no longer segfault,  
>>>>>>> now
>>>>>>> printing "qemu: could not read disk image /path/to/image".
>>>>>
>>>>> I would assume -z,allextract isn't doing what we would like it  
>>>>> to do on
>>>>> OpenSolaris.
>
> This problem is still around after Juan's Makefile reorganizations.
>
> Before, I had provided two alternative patches:
>
> * The first version wrote the list of libqemu_common.a's and $ 
> (HWLIB)'s object files into a text file from Makefile[.hw] that was  
> later read in Makefile.target.
>
> * The second version was using dedicated Makefile[.hw] targets for  
> printing the object files to stdout for use by Makefile.target,  
> avoiding the need to write an intermediate file.
>
> Avi had preferred a variation of the first version for reduced  
> complexity.
>
> Other ideas that crossed my mind were:
> * using GNU ld directly instead of gcc for linking (broken by -Wl  
> and some other LDFLAGS)
> * extracting the .a archive to a temporary directory from the target  
> Makefile and obtaining the names by `ls *.o` (similar to libtool)

The attached patches showcase the latter. $(ARLIBS) are extracted  
to .tmpobjs/<libname>/ and their *.o objects are linked individually.  
Filtering to *.o was necessary because on OSX archives contain non-.o  
files that otherwise break compilation.
The extraction showed that libqemu_common.a contains two nbd.o files,  
one from ./nbd.c and one from ./block/nbd.c. The second patch thus  
renames block/nbd.o to distinguish the two and to avoid linker errors.  
A more permanent solution would be to rename the nbd.c file.
With those two patches once again QEMU works on both OpenSolaris and  
Mac OS X, for in-tree and out-of-tree builds.

Andreas

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diff --git a/rules.mak b/rules.mak
index 59cb185..6bbd292 100644
--- a/rules.mak
+++ b/rules.mak
@@ -23,7 +23,7 @@ QEMU_CFLAGS += -MMD -MP -MT $@
 	$(call quiet-command,$(CC) $(QEMU_CFLAGS) $(CFLAGS) -c -o $@ $<,"  OBJC  $(TARGET_DIR)$@")
 
 #LINK = $(call quiet-command,$(CC) $(QEMU_CFLAGS) $(CFLAGS) $(LDFLAGS) -o $@ $(1) $(ARLIBS_BEGIN) $(ARLIBS) $(ARLIBS_END) $(LIBS),"  LINK  $(TARGET_DIR)$@")
-LINK = $(call quiet-command,{ rm -rf .tmpobjs;mkdir .tmpobjs$(foreach arlib,$(ARLIBS),;(mkdir .tmpobjs/$(notdir $(arlib));cd .tmpobjs/$(notdir $(arlib)) && ar x ../../$(arlib)));$(CC) $(QEMU_CFLAGS) $(CFLAGS) $(LDFLAGS) -o $@ $(1) $(foreach arlib,$(ARLIBS),$(foreach obj,$(shell $(AR) t $(arlib)),.tmpobjs/$(notdir $(arlib))/$(obj))) $(LIBS);},"  LINK  $(TARGET_DIR)$@")
+LINK = $(call quiet-command,{ rm -rf .tmpobjs;mkdir .tmpobjs$(foreach arlib,$(ARLIBS),;(mkdir .tmpobjs/$(notdir $(arlib));cd .tmpobjs/$(notdir $(arlib)) && ar x ../../$(arlib)));$(CC) $(QEMU_CFLAGS) $(CFLAGS) $(LDFLAGS) -o $@ $(1) $(foreach arlib,$(ARLIBS),$(foreach obj,$(filter %.o,$(shell $(AR) t $(arlib))),.tmpobjs/$(notdir $(arlib))/$(obj))) $(LIBS);},"  LINK  $(TARGET_DIR)$@")
 
 %$(EXESUF): %.o
 	$(call LINK,$^)

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diff --git a/Makefile b/Makefile
index 63a7128..69df44c 100644
--- a/Makefile
+++ b/Makefile
@@ -91,11 +91,14 @@ block-obj-$(CONFIG_LINUX_AIO) += linux-aio.o
 
 block-nested-y += cow.o qcow.o vdi.o vmdk.o cloop.o dmg.o bochs.o vpc.o vvfat.o
 block-nested-y += qcow2.o qcow2-refcount.o qcow2-cluster.o qcow2-snapshot.o
-block-nested-y += parallels.o nbd.o
+block-nested-y += parallels.o nbd--.o
 block-nested-$(CONFIG_WIN32) += raw-win32.o
 block-nested-$(CONFIG_POSIX) += raw-posix.o
 block-nested-$(CONFIG_CURL) += curl.o
 
+block/nbd--.o: block/nbd.c $(GENERATED_HEADERS)
+	$(call quiet-command,$(CC) $(QEMU_CFLAGS) $(CFLAGS) -c -o $@ $<,"  CC    $(TARGET_DIR)$@")
+
 block-obj-y +=  $(addprefix block/, $(block-nested-y))
 
 net-obj-y = net.o