[Qemu-devel] [PATCH] Put all trace.o into libqemuutil.a

[Qemu-devel] [PATCH] Put all trace.o into libqemuutil.a

[Xu, Anthony]

Put all trace.o into libqemuutil.a

Currently all trace.o are linked into qemu-system, qemu-img, 
qemu-nbd, qemu-io etc., even the corresponding components 
are not included.
Put all trace.o into libqemuutil.a that the linker would only pull in .o 
files containing symbols that are actually referenced by the 
program.


Signed-off -by: Anthony Xu <anthony.xu@intel.com>



diff --git a/Makefile b/Makefile
index 6c359b2..31d41a7 100644
--- a/Makefile
+++ b/Makefile
@@ -346,7 +346,7 @@ dtc/%:
        mkdir -p $@

 $(SUBDIR_RULES): libqemuutil.a libqemustub.a $(common-obj-y) $(chardev-obj-y) \
-       $(qom-obj-y) $(crypto-aes-obj-$(CONFIG_USER_ONLY)) $(trace-obj-y)
+       $(qom-obj-y) $(crypto-aes-obj-$(CONFIG_USER_ONLY))

 ROMSUBDIR_RULES=$(patsubst %,romsubdir-%, $(ROMS))
 # Only keep -O and -g cflags
@@ -366,11 +366,11 @@ Makefile: $(version-obj-y)
 # Build libraries

 libqemustub.a: $(stub-obj-y)
-libqemuutil.a: $(util-obj-y)
+libqemuutil.a: $(util-obj-y) $(trace-obj-y)

 ######################################################################

-COMMON_LDADDS = $(trace-obj-y) libqemuutil.a libqemustub.a
+COMMON_LDADDS = libqemuutil.a libqemustub.a

 qemu-img.o: qemu-img-cmds.h

diff --git a/Makefile.target b/Makefile.target
index d5ff0c7..69239e0 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -185,8 +185,7 @@ dummy := $(call unnest-vars,.., \
                qom-obj-y \
                io-obj-y \
                common-obj-y \
-               common-obj-m \
-               trace-obj-y)
+               common-obj-m)
 target-obj-y := $(target-obj-y-save)
 all-obj-y += $(common-obj-y)
 all-obj-y += $(target-obj-y)
@@ -198,7 +197,7 @@ all-obj-$(CONFIG_SOFTMMU) += $(io-obj-y)

 $(QEMU_PROG_BUILD): config-devices.mak

-COMMON_LDADDS = $(trace-obj-y) ../libqemuutil.a ../libqemustub.a
+COMMON_LDADDS = ../libqemuutil.a ../libqemustub.a

 # build either PROG or PROGW
 $(QEMU_PROG_BUILD): $(all-obj-y) $(COMMON_LDADDS)
diff --git a/tests/Makefile.include b/tests/Makefile.include
index f3de81f..579ec07 100644
--- a/tests/Makefile.include
+++ b/tests/Makefile.include
@@ -519,7 +519,7 @@ QEMU_CFLAGS += -I$(SRC_PATH)/tests


 # Deps that are common to various different sets of tests below
-test-util-obj-y = $(trace-obj-y) libqemuutil.a libqemustub.a
+test-util-obj-y = libqemuutil.a libqemustub.a
 test-qom-obj-y = $(qom-obj-y) $(test-util-obj-y)
 test-qapi-obj-y = tests/test-qapi-visit.o tests/test-qapi-types.o \
        tests/test-qapi-event.o tests/test-qmp-introspect.o \

Re: [Qemu-devel] [PATCH] Put all trace.o into libqemuutil.a

[Lluís Vilanova]

Xu, Anthony writes:

> Put all trace.o into libqemuutil.a
> Currently all trace.o are linked into qemu-system, qemu-img, 
> qemu-nbd, qemu-io etc., even the corresponding components 
> are not included.
> Put all trace.o into libqemuutil.a that the linker would only pull in .o 
> files containing symbols that are actually referenced by the 
> program.

I think this change conflicts with some of the guest code tracing patches I have
in the queue (I won't be able to send the new series until the end of the month,
sorry).

AFAIR, some of my patches need to link different code for utils and qemu's main
binaries. Although there might be a better way of doing it that I missed.


Cheers,
  Lluis

Re: [Qemu-devel] [PATCH] Put all trace.o into libqemuutil.a

[Stefan Hajnoczi]

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On Wed, Apr 05, 2017 at 11:15:58AM +0300, Lluís Vilanova wrote:
> Xu, Anthony writes:
> 
> > Put all trace.o into libqemuutil.a
> > Currently all trace.o are linked into qemu-system, qemu-img, 
> > qemu-nbd, qemu-io etc., even the corresponding components 
> > are not included.
> > Put all trace.o into libqemuutil.a that the linker would only pull in .o 
> > files containing symbols that are actually referenced by the 
> > program.
> 
> I think this change conflicts with some of the guest code tracing patches I have
> in the queue (I won't be able to send the new series until the end of the month,
> sorry).
> 
> AFAIR, some of my patches need to link different code for utils and qemu's main
> binaries. Although there might be a better way of doing it that I missed.

I don't know the details of your unsent patches, but one possible
solution is stubs/* where we stub out functions that are unavailable in
tools.  That way the same code links in the main QEMU program and in
utils.

When the code runs in utils, it either doesn't take the code path that
reaches the stub function or it calls the stub and continues unaware
that the call was a noop.

If you want to discuss further, feel free to post an RFC preview series
of your work in progress.

Stefan

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Re: [Qemu-devel] [PATCH] Put all trace.o into libqemuutil.a

[Daniel P. Berrange]

On Tue, Apr 04, 2017 at 09:39:39PM +0000, Xu, Anthony wrote:
> Put all trace.o into libqemuutil.a
> 
> Currently all trace.o are linked into qemu-system, qemu-img, 
> qemu-nbd, qemu-io etc., even the corresponding components 
> are not included.
> Put all trace.o into libqemuutil.a that the linker would only pull in .o 
> files containing symbols that are actually referenced by the 
> program.
> 
> 
> Signed-off -by: Anthony Xu <anthony.xu@intel.com>

Reviewed-by: Daniel P. Berrange <berrange@redhat.com>


Regards,
Daniel
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Re: [Qemu-devel] [PATCH] Put all trace.o into libqemuutil.a

[Stefan Hajnoczi]

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On Tue, Apr 04, 2017 at 09:39:39PM +0000, Xu, Anthony wrote:

Thanks, applied to my tracing-next tree:
https://github.com/stefanha/qemu/commits/tracing-next

I fixed up the patch when applying it.  Comments below:

> Put all trace.o into libqemuutil.a

Please use the "trace: " prefix for tracing patches.

All components of QEMU have commonly used prefixes that make it easy to
identify which area a patch affects.  People reading the mailing list or
grepping through git logs rely on this.

> 
> Currently all trace.o are linked into qemu-system, qemu-img, 
> qemu-nbd, qemu-io etc., even the corresponding components 
> are not included.
> Put all trace.o into libqemuutil.a that the linker would only pull in .o 
> files containing symbols that are actually referenced by the 
> program.
> 
> 
> Signed-off -by: Anthony Xu <anthony.xu@intel.com>

Please use git-format-patch(1) to send correctly formatted patches in
the future.  git-am(1) was unable to apply your email and I had to do it
manually.

Stefan

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