[Qemu-devel] [RFC PATCH v2 0/6] Shared Library Module Support

[Qemu-devel] [RFC PATCH v2 0/6] Shared Library Module Support

[Fam Zheng]

This series implements feature of shared object building as described in:

http://wiki.qemu.org/Features/Modules

It's achieved in three steps, with extra bonus to change curl and qed to a
shared library module in the end (only to demonstrate the usage, no "make
install" support of .so files yet).

v2: <inline below>

1. Allow per object cflags and libs:

    [01/06] make.rule: fix $(obj) to a real relative path
            Slightly changed, added $(obj-base) to work with module dependency
            variable expansion.

    [02/06] rule.mak: allow per object cflags and libs

2. Rules for building .so:

    [03/06] Makefile: introduce common-obj-m and block-obj-m for DSO
            [Richard] Change some rule generation and don't use "ln -r" to for
            intermediate object.

3. Code to load module. All .so files are scanned and loaded when program
   starts:

    [04/06] module: implement module loading function
            [mjt] Don't load all .so unconditionally, subsystem call
            module_load for specific type.
            [Lluís] Used configure time prefix as the module base directory.

4. curl and qed adoption:

    [05/06] curl: build as shared library
    [06/06] qed: build as shared library
            Added to demostrate how to write multi-file module.


Fam Zheng (6):
  make.rule: fix $(obj) to a real relative path
  rule.mak: allow per object cflags and libs
  Makefile: introduce common-obj-m and block-obj-m for DSO
  module: implement module loading function
  curl: build as shared library
  qed: build as shared library

 Makefile              | 32 ++++++++++++++++++++++++++++---
 Makefile.objs         | 14 +++++++++++++-
 Makefile.target       |  3 ++-
 block.c               |  1 +
 block/Makefile.objs   |  7 ++++---
 bsd-user/main.c       |  3 +++
 configure             | 28 +++++++++++++++------------
 include/qemu/module.h |  9 +++++++++
 linux-user/main.c     |  3 +++
 qemu-img.c            |  1 +
 rules.mak             | 25 +++++++++++++++++++------
 scripts/create_config |  4 ++++
 ui/console.c          |  1 +
 util/Makefile.objs    |  2 ++
 util/module.c         | 52 +++++++++++++++++++++++++++++++++++++++++++++++++++
 vl.c                  |  2 ++
 16 files changed, 161 insertions(+), 26 deletions(-)

-- 
1.8.3.1

[Qemu-devel] [RFC PATCH v2 1/6] make.rule: fix $(obj) to a real relative path

[Fam Zheng]

Makefile.target includes rule.mak and unnested common-obj-y, then prefix
them with '../', this will ignore object specific QEMU_CFLAGS in subdir
Makefile.objs:

    $(obj)/curl.o: QEMU_CFLAGS += $(CURL_CFLAGS)

Because $(obj) here is './block', instead of '../block'. This doesn't
hurt compiling because we basically build all .o from top Makefile,
before entering Makefile.target, but it will affact arriving per-object
libs support.

The starting point of $(obj) is fixed in $(obj-base) before including
./Makefile.objs, to get consistency with nested Makefile rules in target
rule and variable definition.

Signed-off-by: Fam Zheng <famz@redhat.com>
---
 Makefile.target | 3 ++-
 rules.mak       | 7 ++++---
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/Makefile.target b/Makefile.target
index 9a49852..0ab60bd 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -144,12 +144,13 @@ endif # CONFIG_SOFTMMU
 %/translate.o: QEMU_CFLAGS += $(TRANSLATE_OPT_CFLAGS)
 
 nested-vars += obj-y
+obj-base := ..
 
 # This resolves all nested paths, so it must come last
 include $(SRC_PATH)/Makefile.objs
 
 all-obj-y = $(obj-y)
-all-obj-y += $(addprefix ../, $(common-obj-y))
+all-obj-y += $(addprefix $(obj)/, $(common-obj-y))
 
 ifndef CONFIG_HAIKU
 LIBS+=-lm
diff --git a/rules.mak b/rules.mak
index 4499745..eef1b71 100644
--- a/rules.mak
+++ b/rules.mak
@@ -103,7 +103,7 @@ clean: clean-timestamp
 
 # magic to descend into other directories
 
-obj := .
+obj = $(obj-base)
 old-nested-dirs :=
 
 define push-var
@@ -119,9 +119,10 @@ endef
 
 define unnest-dir
 $(foreach var,$(nested-vars),$(call push-var,$(var),$1/))
-$(eval obj := $(obj)/$1)
+$(eval old-obj := $(obj))
+$(eval obj := $(if $(obj),$(obj)/$1,$1))
 $(eval include $(SRC_PATH)/$1/Makefile.objs)
-$(eval obj := $(patsubst %/$1,%,$(obj)))
+$(eval obj := $(old-obj))
 $(foreach var,$(nested-vars),$(call pop-var,$(var),$1/))
 endef
 
-- 
1.8.3.1

[Qemu-devel] [RFC PATCH v2 2/6] rule.mak: allow per object cflags and libs

[Fam Zheng]

Adds extract-libs in LINK to expand any "per object libs", the syntax to define
such a libs options is like:

        $(obj)/curl.o-libs = $(CURL_LIBS)

in block/Makefile.objs.

Similarly,

        $(obj)foo.o-cflags = $(FOO_CFLAGS)

is also supported.

Signed-off-by: Fam Zheng <famz@redhat.com>
---
 rules.mak | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/rules.mak b/rules.mak
index eef1b71..e581d55 100644
--- a/rules.mak
+++ b/rules.mak
@@ -17,15 +17,17 @@ QEMU_DGFLAGS += -MMD -MP -MT $@ -MF $(*D)/$(*F).d
 # Same as -I$(SRC_PATH) -I., but for the nested source/object directories
 QEMU_INCLUDES += -I$(<D) -I$(@D)
 
+extract-libs = $(strip $(foreach o,$1,$($(obj-base)$o-libs)))
+
 %.o: %.c
-	$(call quiet-command,$(CC) $(QEMU_INCLUDES) $(QEMU_CFLAGS) $(QEMU_DGFLAGS) $(CFLAGS) -c -o $@ $<,"  CC    $(TARGET_DIR)$@")
+	$(call quiet-command,$(CC) $(QEMU_INCLUDES) $(QEMU_CFLAGS) $(QEMU_DGFLAGS) $(CFLAGS) $($@-cflags) -c -o $@ $<,"  CC    $(TARGET_DIR)$@")
 %.o: %.rc
 	$(call quiet-command,$(WINDRES) -I. -o $@ $<,"  RC    $(TARGET_DIR)$@")
 
 ifeq ($(LIBTOOL),)
 LINK = $(call quiet-command,$(CC) $(QEMU_CFLAGS) $(CFLAGS) $(LDFLAGS) -o $@ \
        $(sort $(filter %.o, $1)) $(filter-out %.o, $1) $(version-obj-y) \
-       $(LIBS),"  LINK  $(TARGET_DIR)$@")
+       $(call extract-libs,$^) $(LIBS),"  LINK  $(TARGET_DIR)$@")
 else
 LIBTOOL += $(if $(V),,--quiet)
 %.lo: %.c
@@ -41,7 +43,7 @@ LINK = $(call quiet-command,\
        $(sort $(filter %.o, $1)) $(filter-out %.o, $1) \
        $(if $(filter %.lo %.la,$^),$(version-lobj-y),$(version-obj-y)) \
        $(if $(filter %.lo %.la,$^),$(LIBTOOLFLAGS)) \
-       $(LIBS),$(if $(filter %.lo %.la,$^),"lt LINK ", "  LINK  ")"$(TARGET_DIR)$@")
+       $(call extract-libs,$^) $(LIBS),$(if $(filter %.lo %.la,$^),"lt LINK ", "  LINK  ")"$(TARGET_DIR)$@")
 endif
 
 %.asm: %.S
-- 
1.8.3.1

[Qemu-devel] [RFC PATCH v2 3/6] Makefile: introduce common-obj-m and block-obj-m for DSO

[Fam Zheng]

Add necessary rules and flags for shared object generation.
$(common-obj-m) will include $(block-obj-m), like $(common-obj-y) does
for $(block-obj-y). The new rules introduced here are:

0) For all %.so compiling:

    QEMU_CFLAGS += -shared -fPIC

1) %.o in $(common-obj-m) is compiled to %.o, with "QEMU_CFLAGS +=
-shared -fPIC". Then linked to %.so.

2) %.mo in $(common-obj-m) is the placeholder for %.so for pattern
matching in Makefile. It's linked to "-shared" with all its dependencies
(multiple *.o) as input. Which means the list of depended objects must
be ruled out in each sub-Makefile.objs with an variable:

    $(obj)/foo.mo-obj := $(addprefix $(obj)/,bar.o baz.o qux.o)

Notice that $(obj)/ is required for both target and dependency in the
rule. DSO suffix (.so) is configure variable (.dll for Windows).

Signed-off-by: Fam Zheng <famz@redhat.com>
---
 Makefile      | 32 +++++++++++++++++++++++++++++---
 Makefile.objs | 14 +++++++++++++-
 configure     |  3 +++
 rules.mak     | 10 ++++++++++
 4 files changed, 55 insertions(+), 4 deletions(-)

diff --git a/Makefile b/Makefile
index 806946e..cf47ea9 100644
--- a/Makefile
+++ b/Makefile
@@ -56,7 +56,7 @@ Makefile: ;
 configure: ;
 
 .PHONY: all clean cscope distclean dvi html info install install-doc \
-	pdf recurse-all speed test dist
+	pdf recurse-all speed test dist modules
 
 $(call set-vpath, $(SRC_PATH))
 
@@ -121,7 +121,30 @@ ifeq ($(CONFIG_SMARTCARD_NSS),y)
 include $(SRC_PATH)/libcacard/Makefile
 endif
 
-all: $(DOCS) $(TOOLS) $(HELPERS-y) recurse-all
+all: $(DOCS) $(TOOLS) $(HELPERS-y) recurse-all modules
+
+mod-obj-m = $(patsubst %.o,%$(DSOSUF),$(filter %.o,$(common-obj-m))) \
+            $(patsubst %.mo,%$(DSOSUF),$(filter %.mo,$(common-obj-m)))
+
+# Generate rules for single file modules (%.so: %.o).
+$(foreach o,$(filter %.o,$(common-obj-m)),$(eval \
+	$(patsubst %.o,%.so,$o): $o ))
+
+# For multi file modules, dependencies should be listed explicitly in
+# Makefile.objs as
+#     $(obj)/foo.mo-obj := $(obj)/bar.o $(obj)/biz.o
+$(foreach o,$(filter %.mo,$(mod-obj-m)),$(eval \
+	$o: $($o-obj)))
+
+%.mo:
+	$(if $(BUILD_DYNAMIC), \
+		$(call quiet-command,$(CC) $(sort $^) -shared -o $@,"  LD[M] $(TARGET_DIR)$@"), \
+		$(call quiet-command,$(AR) rcs $@ $(sort $^),"  AR    $(TARGET_DIR)$@"))
+
+
+modules: $(mod-obj-m)
+modules: BUILD_DYNAMIC = 1
+modules: QEMU_CFLAGS += -shared -fPIC
 
 config-host.h: config-host.h-timestamp
 config-host.h-timestamp: config-host.mak
@@ -155,7 +178,7 @@ subdir-dtc:dtc/libfdt dtc/tests
 dtc/%:
 	mkdir -p $@
 
-$(SUBDIR_RULES): libqemuutil.a libqemustub.a $(common-obj-y)
+$(SUBDIR_RULES): libqemuutil.a libqemustub.a $(common-obj-y) $(common-obj-m)
 
 ROMSUBDIR_RULES=$(patsubst %,romsubdir-%, $(ROMS))
 romsubdir-%:
@@ -235,6 +258,9 @@ clean:
 	rm -f qemu-options.def
 	find . -name '*.[oda]' -type f -exec rm -f {} +
 	find . -name '*.l[oa]' -type f -exec rm -f {} +
+	find . -name '*'$(DSOSUF) -type f -exec rm -f {} +
+	find . -name '*.mo' -type f -exec rm -f {} +
+
 	rm -f $(TOOLS) $(HELPERS-y) qemu-ga TAGS cscope.* *.pod *~ */*~
 	rm -Rf .libs
 	rm -f qemu-img-cmds.h
diff --git a/Makefile.objs b/Makefile.objs
index f46a4cd..8984a20 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -19,6 +19,8 @@ block-obj-y += qemu-coroutine.o qemu-coroutine-lock.o qemu-coroutine-io.o
 block-obj-y += qemu-coroutine-sleep.o
 block-obj-y += coroutine-$(CONFIG_COROUTINE_BACKEND).o
 
+block-obj-m = block/
+
 ifeq ($(CONFIG_VIRTIO)$(CONFIG_VIRTFS)$(CONFIG_PCI),yyy)
 # Lots of the fsdev/9pcode is pulled in by vl.c via qemu_fsdev_add.
 # only pull in the actual virtio-9p device if we also enabled virtio.
@@ -83,6 +85,9 @@ common-obj-$(CONFIG_SMARTCARD_NSS) += $(libcacard-y)
 
 common-obj-y += qmp-marshal.o
 common-obj-y += qmp.o hmp.o
+
+common-obj-m = $(block-obj-m)
+
 endif
 
 ######################################################################
@@ -121,5 +126,12 @@ nested-vars += \
 	util-obj-y \
 	qga-obj-y \
 	block-obj-y \
-	common-obj-y
+	block-obj-m \
+	common-obj-y \
+	common-obj-m
+
 dummy := $(call unnest-vars)
+
+# static linked mods are expanded to .o list
+dummy := $(call expand-mod-obj,common-obj-y)
+dummy := $(call expand-mod-obj,block-obj-y)
diff --git a/configure b/configure
index af6b048..75abb87 100755
--- a/configure
+++ b/configure
@@ -190,6 +190,7 @@ mingw32="no"
 gcov="no"
 gcov_tool="gcov"
 EXESUF=""
+DSOSUF=".so"
 prefix="/usr/local"
 mandir="\${prefix}/share/man"
 datadir="\${prefix}/share"
@@ -584,6 +585,7 @@ fi
 
 if test "$mingw32" = "yes" ; then
   EXESUF=".exe"
+  DSOSUF=".dll"
   QEMU_CFLAGS="-DWIN32_LEAN_AND_MEAN -DWINVER=0x501 $QEMU_CFLAGS"
   # enable C99/POSIX format strings (needs mingw32-runtime 3.15 or later)
   QEMU_CFLAGS="-D__USE_MINGW_ANSI_STDIO=1 $QEMU_CFLAGS"
@@ -4175,6 +4177,7 @@ echo "LIBTOOLFLAGS=$LIBTOOLFLAGS" >> $config_host_mak
 echo "LIBS+=$LIBS" >> $config_host_mak
 echo "LIBS_TOOLS+=$libs_tools" >> $config_host_mak
 echo "EXESUF=$EXESUF" >> $config_host_mak
+echo "DSOSUF=$DSOSUF" >> $config_host_mak
 echo "LIBS_QGA+=$libs_qga" >> $config_host_mak
 echo "POD2MAN=$POD2MAN" >> $config_host_mak
 echo "TRANSLATE_OPT_CFLAGS=$TRANSLATE_OPT_CFLAGS" >> $config_host_mak
diff --git a/rules.mak b/rules.mak
index e581d55..0a39499 100644
--- a/rules.mak
+++ b/rules.mak
@@ -58,6 +58,10 @@ endif
 %.o: %.dtrace
 	$(call quiet-command,dtrace -o $@ -G -s $<, "  GEN   $(TARGET_DIR)$@")
 
+%$(DSOSUF): QEMU_CLFAGS += -shared -fPIC
+%$(DSOSUF): %.o
+	$(call quiet-command,$(LD) $< -o $@ -shared,"  LD[M] $(TARGET_DIR)$@")
+
 %$(EXESUF): %.o
 	$(call LINK,$^)
 
@@ -145,3 +149,9 @@ $(shell mkdir -p $(sort $(foreach var,$(nested-vars),$(dir $($(var))))))
 $(foreach var,$(nested-vars), $(eval \
   -include $(addsuffix *.d, $(sort $(dir $($(var)))))))
 endef
+
+define expand-mod-obj
+$(eval pref = $(if $(obj-base),$(obj-base)/,))
+$(eval t = $(foreach o,$($1),$(if $($(pref)$o-obj),$($(pref)$o-obj),$o)))
+$(eval $1 = $t)
+endef
-- 
1.8.3.1

[Qemu-devel] [RFC PATCH v2 4/6] module: implement module loading function

[Fam Zheng]

Added three types of modules:

    typedef enum {
        MODULE_LOAD_BLOCK = 0,
        MODULE_LOAD_UI,
        MODULE_LOAD_NET,
        MODULE_LOAD_MAX,
    } module_load_type;

and their loading function:

    void module_load(module_load_type).

which loads all ".so" files in a subdir under "${PREFIX}/qemu/", e.g.
"/usr/lib/qemu/block". Modules of each type should be loaded before
respective subsystem initialization code.

Requires gmodule-2.0 from glib.

Signed-off-by: Fam Zheng <famz@redhat.com>
---
 block.c               |  1 +
 bsd-user/main.c       |  3 +++
 configure             | 20 +++++++++++---------
 include/qemu/module.h |  9 +++++++++
 linux-user/main.c     |  3 +++
 qemu-img.c            |  1 +
 scripts/create_config |  4 ++++
 ui/console.c          |  1 +
 util/Makefile.objs    |  2 ++
 util/module.c         | 52 +++++++++++++++++++++++++++++++++++++++++++++++++++
 vl.c                  |  2 ++
 11 files changed, 89 insertions(+), 9 deletions(-)

diff --git a/block.c b/block.c
index a387c1a..49ab0ce 100644
--- a/block.c
+++ b/block.c
@@ -4009,6 +4009,7 @@ BlockDriverAIOCB *bdrv_aio_discard(BlockDriverState *bs,
 
 void bdrv_init(void)
 {
+    module_load(MODULE_LOAD_BLOCK);
     module_call_init(MODULE_INIT_BLOCK);
 }
 
diff --git a/bsd-user/main.c b/bsd-user/main.c
index f9246aa..6cb9e35 100644
--- a/bsd-user/main.c
+++ b/bsd-user/main.c
@@ -33,6 +33,7 @@
 #include "tcg.h"
 #include "qemu/timer.h"
 #include "qemu/envlist.h"
+#include "qemu/module.h"
 
 int singlestep;
 #if defined(CONFIG_USE_GUEST_BASE)
@@ -749,6 +750,8 @@ int main(int argc, char **argv)
     if (argc <= 1)
         usage();
 
+    module_load(MODULE_LOAD_UI);
+    module_load(MODULE_LOAD_NET);
     module_call_init(MODULE_INIT_QOM);
 
     if ((envlist = envlist_create()) == NULL) {
diff --git a/configure b/configure
index 75abb87..7fec1c7 100755
--- a/configure
+++ b/configure
@@ -2249,15 +2249,17 @@ if test "$mingw32" = yes; then
 else
     glib_req_ver=2.12
 fi
-if $pkg_config --atleast-version=$glib_req_ver gthread-2.0 > /dev/null 2>&1
-then
-    glib_cflags=`$pkg_config --cflags gthread-2.0 2>/dev/null`
-    glib_libs=`$pkg_config --libs gthread-2.0 2>/dev/null`
-    LIBS="$glib_libs $LIBS"
-    libs_qga="$glib_libs $libs_qga"
-else
-    error_exit "glib-$glib_req_ver required to compile QEMU"
-fi
+for i in gthread-2.0 gmodule-2.0; do
+    if $pkg_config --atleast-version=$glib_req_ver $i > /dev/null 2>&1
+    then
+        glib_cflags=`$pkg_config --cflags $i 2>/dev/null`
+        glib_libs=`$pkg_config --libs $i 2>/dev/null`
+        LIBS="$glib_libs $LIBS"
+        libs_qga="$glib_libs $libs_qga"
+    else
+        error_exit "glib-$glib_req_ver required to compile QEMU"
+    fi
+done
 
 ##########################################
 # pixman support probe
diff --git a/include/qemu/module.h b/include/qemu/module.h
index c4ccd57..f00bc25 100644
--- a/include/qemu/module.h
+++ b/include/qemu/module.h
@@ -37,4 +37,13 @@ void register_module_init(void (*fn)(void), module_init_type type);
 
 void module_call_init(module_init_type type);
 
+typedef enum {
+    MODULE_LOAD_BLOCK = 0,
+    MODULE_LOAD_UI,
+    MODULE_LOAD_NET,
+    MODULE_LOAD_MAX,
+} module_load_type;
+
+void module_load(module_load_type type);
+
 #endif
diff --git a/linux-user/main.c b/linux-user/main.c
index 03859bc..9cbac14 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -34,6 +34,7 @@
 #include "qemu/timer.h"
 #include "qemu/envlist.h"
 #include "elf.h"
+#include <qemu/module.h>
 
 char *exec_path;
 
@@ -3547,6 +3548,8 @@ int main(int argc, char **argv, char **envp)
     int i;
     int ret;
 
+    module_load(MODULE_LOAD_UI);
+    module_load(MODULE_LOAD_NET);
     module_call_init(MODULE_INIT_QOM);
 
     qemu_cache_utils_init(envp);
diff --git a/qemu-img.c b/qemu-img.c
index b9a848d..063e6bf 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -34,6 +34,7 @@
 #include <getopt.h>
 #include <stdio.h>
 #include <stdarg.h>
+#include "qemu/module.h"
 
 #ifdef _WIN32
 #include <windows.h>
diff --git a/scripts/create_config b/scripts/create_config
index b1adbf5..7a54f2d 100755
--- a/scripts/create_config
+++ b/scripts/create_config
@@ -25,6 +25,7 @@ case $line in
  prefix=*)
     # save for the next definitions
     prefix=${line#*=}
+    echo "#define CONFIG_PREFIX \"$prefix\""
     ;;
  CONFIG_AUDIO_DRIVERS=*)
     drivers=${line#*=}
@@ -104,6 +105,9 @@ case $line in
     value=${line#*=}
     echo "#define $name $value"
     ;;
+ DSOSUF=*)
+    echo "#define HOST_DSOSUF \"${line#*=}\""
+    ;;
 esac
 
 done # read
diff --git a/ui/console.c b/ui/console.c
index aad4fc9..ad90950 100644
--- a/ui/console.c
+++ b/ui/console.c
@@ -27,6 +27,7 @@
 #include "qemu/timer.h"
 #include "qmp-commands.h"
 #include "sysemu/char.h"
+#include "qemu/module.h"
 
 //#define DEBUG_CONSOLE
 #define DEFAULT_BACKSCROLL 512
diff --git a/util/Makefile.objs b/util/Makefile.objs
index dc72ab0..33e56b0 100644
--- a/util/Makefile.objs
+++ b/util/Makefile.objs
@@ -11,3 +11,5 @@ util-obj-y += iov.o aes.o qemu-config.o qemu-sockets.o uri.o notify.o
 util-obj-y += qemu-option.o qemu-progress.o
 util-obj-y += hexdump.o
 util-obj-y += crc32c.o
+
+$(obj)/module.o-libs := -lglib
diff --git a/util/module.c b/util/module.c
index 7acc33d..7254b1a 100644
--- a/util/module.c
+++ b/util/module.c
@@ -13,6 +13,8 @@
  * GNU GPL, version 2 or (at your option) any later version.
  */
 
+#include <gmodule.h>
+#include <dirent.h>
 #include "qemu-common.h"
 #include "qemu/queue.h"
 #include "qemu/module.h"
@@ -79,3 +81,53 @@ void module_call_init(module_init_type type)
         e->init();
     }
 }
+
+void module_load(module_load_type type)
+{
+    const char *path;
+    const char *dsosuf = HOST_DSOSUF;
+    char fname[1024];
+    int suf_len = strlen(dsosuf);
+    DIR *dp;
+    struct dirent *ep = NULL;
+    GModule *g_module;
+
+    if (!g_module_supported()) {
+        return;
+    }
+
+    switch (type) {
+    case MODULE_LOAD_BLOCK:
+        path = CONFIG_PREFIX "/qemu/block/";
+        break;
+    case MODULE_LOAD_UI:
+        path = CONFIG_PREFIX "/qemu/ui/";
+        break;
+    case MODULE_LOAD_NET:
+        path = CONFIG_PREFIX "/qemu/net/";
+        break;
+    default:
+        return;
+    }
+
+    dp = opendir(path);
+    if (!dp) {
+        fprintf(stderr, "Failed to open dir %s\n", path);
+        return;
+    }
+    for (ep = readdir(dp); ep; ep = readdir(dp)) {
+        int len = strlen(ep->d_name);
+        if (len > suf_len &&
+                !strcmp(&ep->d_name[len - suf_len], dsosuf)) {
+            pstrcpy(fname, sizeof(fname), path);
+            pstrcat(fname, sizeof(fname), ep->d_name);
+            g_module = g_module_open(fname, G_MODULE_BIND_LAZY);
+            if (!g_module) {
+                fprintf(stderr, "Failed to open module file %s\n",
+                        g_module_error());
+                continue;
+            }
+            printf("Loaded module %s\n", fname);
+        }
+    }
+}
diff --git a/vl.c b/vl.c
index dfbc071..716c2db 100644
--- a/vl.c
+++ b/vl.c
@@ -2940,6 +2940,8 @@ int main(int argc, char **argv, char **envp)
 #endif
     }
 
+    module_load(MODULE_LOAD_UI);
+    module_load(MODULE_LOAD_NET);
     module_call_init(MODULE_INIT_QOM);
 
     qemu_add_opts(&qemu_drive_opts);
-- 
1.8.3.1

[Qemu-devel] [RFC PATCH v2 5/6] curl: build as shared library

[Fam Zheng]

Curl block driver is built as shared object module when enabled.
We have per object cflags and libs support now, move CURL_CFLAGS and
CURL_LIBS from global option variables to a per object basis.

"make install" is not installing it yet, manually copy it to
${prefix}/qemu/block/curl.so to make it loaded.

Signed-off-by: Fam Zheng <famz@redhat.com>
---
 block/Makefile.objs | 3 ++-
 configure           | 5 ++---
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/block/Makefile.objs b/block/Makefile.objs
index 4cf9aa4..b1e1520 100644
--- a/block/Makefile.objs
+++ b/block/Makefile.objs
@@ -23,4 +23,5 @@ common-obj-y += commit.o
 common-obj-y += mirror.o
 common-obj-y += backup.o
 
-$(obj)/curl.o: QEMU_CFLAGS+=$(CURL_CFLAGS)
+$(obj)/curl.o-cflags := $(CURL_CFLAGS)
+$(obj)/curl.o-libs := $(CURL_LIBS)
diff --git a/configure b/configure
index 7fec1c7..4adc267 100755
--- a/configure
+++ b/configure
@@ -2210,8 +2210,6 @@ EOF
   curl_libs=`$curlconfig --libs 2>/dev/null`
   if compile_prog "$curl_cflags" "$curl_libs" ; then
     curl=yes
-    libs_tools="$curl_libs $libs_tools"
-    libs_softmmu="$curl_libs $libs_softmmu"
   else
     if test "$curl" = "yes" ; then
       feature_not_found "curl"
@@ -3889,8 +3887,9 @@ if test "$bswap_h" = "yes" ; then
   echo "CONFIG_MACHINE_BSWAP_H=y" >> $config_host_mak
 fi
 if test "$curl" = "yes" ; then
-  echo "CONFIG_CURL=y" >> $config_host_mak
+  echo "CONFIG_CURL=m" >> $config_host_mak
   echo "CURL_CFLAGS=$curl_cflags" >> $config_host_mak
+  echo "CURL_LIBS=$curl_libs" >> $config_host_mak
 fi
 if test "$brlapi" = "yes" ; then
   echo "CONFIG_BRLAPI=y" >> $config_host_mak
-- 
1.8.3.1

[Qemu-devel] [RFC PATCH v2 6/6] qed: build as shared library

[Fam Zheng]

Another example of DSO build but with multiple files in a module.

Signed-off-by: Fam Zheng <famz@redhat.com>
---
 block/Makefile.objs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/block/Makefile.objs b/block/Makefile.objs
index b1e1520..4cb2ab9 100644
--- a/block/Makefile.objs
+++ b/block/Makefile.objs
@@ -1,7 +1,6 @@
 block-obj-y += raw.o cow.o qcow.o vdi.o vmdk.o cloop.o dmg.o bochs.o vpc.o vvfat.o
 block-obj-y += qcow2.o qcow2-refcount.o qcow2-cluster.o qcow2-snapshot.o qcow2-cache.o
-block-obj-y += qed.o qed-gencb.o qed-l2-cache.o qed-table.o qed-cluster.o
-block-obj-y += qed-check.o
+block-obj-m += qed.mo
 block-obj-y += vhdx.o
 block-obj-y += parallels.o blkdebug.o blkverify.o
 block-obj-y += snapshot.o qapi.o
@@ -25,3 +24,4 @@ common-obj-y += backup.o
 
 $(obj)/curl.o-cflags := $(CURL_CFLAGS)
 $(obj)/curl.o-libs := $(CURL_LIBS)
+$(obj)/qed.mo-obj := $(addprefix $(obj)/,qed.o qed-gencb.o qed-l2-cache.o qed-table.o qed-cluster.o qed-check.o)
-- 
1.8.3.1

Re: [Qemu-devel] [RFC PATCH v2 4/6] module: implement module loading function

[Paolo Bonzini]

Il 06/09/2013 09:28, Fam Zheng ha scritto:
> Added three types of modules:
> 
>     typedef enum {
>         MODULE_LOAD_BLOCK = 0,
>         MODULE_LOAD_UI,
>         MODULE_LOAD_NET,
>         MODULE_LOAD_MAX,
>     } module_load_type;
> 
> and their loading function:
> 
>     void module_load(module_load_type).
> 
> which loads all ".so" files in a subdir under "${PREFIX}/qemu/", e.g.
> "/usr/lib/qemu/block". Modules of each type should be loaded before
> respective subsystem initialization code.
> 
> Requires gmodule-2.0 from glib.
> 
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  block.c               |  1 +
>  bsd-user/main.c       |  3 +++
>  configure             | 20 +++++++++++---------
>  include/qemu/module.h |  9 +++++++++
>  linux-user/main.c     |  3 +++
>  qemu-img.c            |  1 +
>  scripts/create_config |  4 ++++
>  ui/console.c          |  1 +
>  util/Makefile.objs    |  2 ++
>  util/module.c         | 52 +++++++++++++++++++++++++++++++++++++++++++++++++++
>  vl.c                  |  2 ++
>  11 files changed, 89 insertions(+), 9 deletions(-)
> 
> diff --git a/block.c b/block.c
> index a387c1a..49ab0ce 100644
> --- a/block.c
> +++ b/block.c
> @@ -4009,6 +4009,7 @@ BlockDriverAIOCB *bdrv_aio_discard(BlockDriverState *bs,
>  
>  void bdrv_init(void)
>  {
> +    module_load(MODULE_LOAD_BLOCK);
>      module_call_init(MODULE_INIT_BLOCK);
>  }
>  
> diff --git a/bsd-user/main.c b/bsd-user/main.c
> index f9246aa..6cb9e35 100644
> --- a/bsd-user/main.c
> +++ b/bsd-user/main.c
> @@ -33,6 +33,7 @@
>  #include "tcg.h"
>  #include "qemu/timer.h"
>  #include "qemu/envlist.h"
> +#include "qemu/module.h"
>  
>  int singlestep;
>  #if defined(CONFIG_USE_GUEST_BASE)
> @@ -749,6 +750,8 @@ int main(int argc, char **argv)
>      if (argc <= 1)
>          usage();
>  
> +    module_load(MODULE_LOAD_UI);
> +    module_load(MODULE_LOAD_NET);
>      module_call_init(MODULE_INIT_QOM);
>  
>      if ((envlist = envlist_create()) == NULL) {
> diff --git a/configure b/configure
> index 75abb87..7fec1c7 100755
> --- a/configure
> +++ b/configure
> @@ -2249,15 +2249,17 @@ if test "$mingw32" = yes; then
>  else
>      glib_req_ver=2.12
>  fi
> -if $pkg_config --atleast-version=$glib_req_ver gthread-2.0 > /dev/null 2>&1
> -then
> -    glib_cflags=`$pkg_config --cflags gthread-2.0 2>/dev/null`
> -    glib_libs=`$pkg_config --libs gthread-2.0 2>/dev/null`
> -    LIBS="$glib_libs $LIBS"
> -    libs_qga="$glib_libs $libs_qga"
> -else
> -    error_exit "glib-$glib_req_ver required to compile QEMU"
> -fi
> +for i in gthread-2.0 gmodule-2.0; do
> +    if $pkg_config --atleast-version=$glib_req_ver $i > /dev/null 2>&1
> +    then
> +        glib_cflags=`$pkg_config --cflags $i 2>/dev/null`
> +        glib_libs=`$pkg_config --libs $i 2>/dev/null`
> +        LIBS="$glib_libs $LIBS"
> +        libs_qga="$glib_libs $libs_qga"
> +    else
> +        error_exit "glib-$glib_req_ver required to compile QEMU"
> +    fi
> +done
>  
>  ##########################################
>  # pixman support probe
> diff --git a/include/qemu/module.h b/include/qemu/module.h
> index c4ccd57..f00bc25 100644
> --- a/include/qemu/module.h
> +++ b/include/qemu/module.h
> @@ -37,4 +37,13 @@ void register_module_init(void (*fn)(void), module_init_type type);
>  
>  void module_call_init(module_init_type type);
>  
> +typedef enum {
> +    MODULE_LOAD_BLOCK = 0,
> +    MODULE_LOAD_UI,
> +    MODULE_LOAD_NET,
> +    MODULE_LOAD_MAX,
> +} module_load_type;
> +
> +void module_load(module_load_type type);
> +
>  #endif
> diff --git a/linux-user/main.c b/linux-user/main.c
> index 03859bc..9cbac14 100644
> --- a/linux-user/main.c
> +++ b/linux-user/main.c
> @@ -34,6 +34,7 @@
>  #include "qemu/timer.h"
>  #include "qemu/envlist.h"
>  #include "elf.h"
> +#include <qemu/module.h>
>  
>  char *exec_path;
>  
> @@ -3547,6 +3548,8 @@ int main(int argc, char **argv, char **envp)
>      int i;
>      int ret;
>  
> +    module_load(MODULE_LOAD_UI);
> +    module_load(MODULE_LOAD_NET);
>      module_call_init(MODULE_INIT_QOM);
>  
>      qemu_cache_utils_init(envp);
> diff --git a/qemu-img.c b/qemu-img.c
> index b9a848d..063e6bf 100644
> --- a/qemu-img.c
> +++ b/qemu-img.c
> @@ -34,6 +34,7 @@
>  #include <getopt.h>
>  #include <stdio.h>
>  #include <stdarg.h>
> +#include "qemu/module.h"
>  
>  #ifdef _WIN32
>  #include <windows.h>
> diff --git a/scripts/create_config b/scripts/create_config
> index b1adbf5..7a54f2d 100755
> --- a/scripts/create_config
> +++ b/scripts/create_config
> @@ -25,6 +25,7 @@ case $line in
>   prefix=*)
>      # save for the next definitions
>      prefix=${line#*=}
> +    echo "#define CONFIG_PREFIX \"$prefix\""
>      ;;
>   CONFIG_AUDIO_DRIVERS=*)
>      drivers=${line#*=}
> @@ -104,6 +105,9 @@ case $line in
>      value=${line#*=}
>      echo "#define $name $value"
>      ;;
> + DSOSUF=*)
> +    echo "#define HOST_DSOSUF \"${line#*=}\""
> +    ;;
>  esac
>  
>  done # read
> diff --git a/ui/console.c b/ui/console.c
> index aad4fc9..ad90950 100644
> --- a/ui/console.c
> +++ b/ui/console.c
> @@ -27,6 +27,7 @@
>  #include "qemu/timer.h"
>  #include "qmp-commands.h"
>  #include "sysemu/char.h"
> +#include "qemu/module.h"

Why?

>  
>  //#define DEBUG_CONSOLE
>  #define DEFAULT_BACKSCROLL 512
> diff --git a/util/Makefile.objs b/util/Makefile.objs
> index dc72ab0..33e56b0 100644
> --- a/util/Makefile.objs
> +++ b/util/Makefile.objs
> @@ -11,3 +11,5 @@ util-obj-y += iov.o aes.o qemu-config.o qemu-sockets.o uri.o notify.o
>  util-obj-y += qemu-option.o qemu-progress.o
>  util-obj-y += hexdump.o
>  util-obj-y += crc32c.o
> +
> +$(obj)/module.o-libs := -lglib
> diff --git a/util/module.c b/util/module.c
> index 7acc33d..7254b1a 100644
> --- a/util/module.c
> +++ b/util/module.c
> @@ -13,6 +13,8 @@
>   * GNU GPL, version 2 or (at your option) any later version.
>   */
>  
> +#include <gmodule.h>
> +#include <dirent.h>
>  #include "qemu-common.h"
>  #include "qemu/queue.h"
>  #include "qemu/module.h"
> @@ -79,3 +81,53 @@ void module_call_init(module_init_type type)
>          e->init();
>      }
>  }
> +
> +void module_load(module_load_type type)
> +{
> +    const char *path;
> +    const char *dsosuf = HOST_DSOSUF;
> +    char fname[1024];
> +    int suf_len = strlen(dsosuf);
> +    DIR *dp;
> +    struct dirent *ep = NULL;
> +    GModule *g_module;
> +
> +    if (!g_module_supported()) {
> +        return;
> +    }
> +
> +    switch (type) {
> +    case MODULE_LOAD_BLOCK:
> +        path = CONFIG_PREFIX "/qemu/block/";
> +        break;
> +    case MODULE_LOAD_UI:
> +        path = CONFIG_PREFIX "/qemu/ui/";
> +        break;
> +    case MODULE_LOAD_NET:
> +        path = CONFIG_PREFIX "/qemu/net/";
> +        break;
> +    default:
> +        return;
> +    }
> +
> +    dp = opendir(path);
> +    if (!dp) {
> +        fprintf(stderr, "Failed to open dir %s\n", path);
> +        return;
> +    }
> +    for (ep = readdir(dp); ep; ep = readdir(dp)) {
> +        int len = strlen(ep->d_name);
> +        if (len > suf_len &&
> +                !strcmp(&ep->d_name[len - suf_len], dsosuf)) {
> +            pstrcpy(fname, sizeof(fname), path);
> +            pstrcat(fname, sizeof(fname), ep->d_name);

Please use g_strdup_printf instead.

> +            g_module = g_module_open(fname, G_MODULE_BIND_LAZY);

Why G_MODULE_BIND_LAZY?  Performance, I guess?

Having G_MODULE_BIND_LOCAL is probably a good idea too.

Paolo

> +            if (!g_module) {
> +                fprintf(stderr, "Failed to open module file %s\n",
> +                        g_module_error());
> +                continue;
> +            }
> +            printf("Loaded module %s\n", fname);
> +        }
> +    }
> +}
> diff --git a/vl.c b/vl.c
> index dfbc071..716c2db 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -2940,6 +2940,8 @@ int main(int argc, char **argv, char **envp)
>  #endif
>      }
>  
> +    module_load(MODULE_LOAD_UI);
> +    module_load(MODULE_LOAD_NET);
>      module_call_init(MODULE_INIT_QOM);
>  
>      qemu_add_opts(&qemu_drive_opts);
> 

Re: [Qemu-devel] [RFC PATCH v2 3/6] Makefile: introduce common-obj-m and block-obj-m for DSO

[Paolo Bonzini]

Il 06/09/2013 09:28, Fam Zheng ha scritto:
> Add necessary rules and flags for shared object generation.
> $(common-obj-m) will include $(block-obj-m), like $(common-obj-y) does
> for $(block-obj-y). The new rules introduced here are:
> 
> 0) For all %.so compiling:
> 
>     QEMU_CFLAGS += -shared -fPIC
> 
> 1) %.o in $(common-obj-m) is compiled to %.o, with "QEMU_CFLAGS +=
> -shared -fPIC". Then linked to %.so.
> 
> 2) %.mo in $(common-obj-m) is the placeholder for %.so for pattern
> matching in Makefile. It's linked to "-shared" with all its dependencies
> (multiple *.o) as input. Which means the list of depended objects must
> be ruled out in each sub-Makefile.objs with an variable:
> 
>     $(obj)/foo.mo-obj := $(addprefix $(obj)/,bar.o baz.o qux.o)
> 
> Notice that $(obj)/ is required for both target and dependency in the
> rule. DSO suffix (.so) is configure variable (.dll for Windows).

Some kinks to iron, but this is really well-architected.  You took all
the best parts of mjt's patches and fixed almost all the ugly ones.  Kudos!

> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  Makefile      | 32 +++++++++++++++++++++++++++++---
>  Makefile.objs | 14 +++++++++++++-
>  configure     |  3 +++
>  rules.mak     | 10 ++++++++++
>  4 files changed, 55 insertions(+), 4 deletions(-)
> 
> diff --git a/Makefile b/Makefile
> index 806946e..cf47ea9 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -56,7 +56,7 @@ Makefile: ;
>  configure: ;
>  
>  .PHONY: all clean cscope distclean dvi html info install install-doc \
> -	pdf recurse-all speed test dist
> +	pdf recurse-all speed test dist modules
>  
>  $(call set-vpath, $(SRC_PATH))
>  
> @@ -121,7 +121,30 @@ ifeq ($(CONFIG_SMARTCARD_NSS),y)
>  include $(SRC_PATH)/libcacard/Makefile
>  endif
>  
> -all: $(DOCS) $(TOOLS) $(HELPERS-y) recurse-all
> +all: $(DOCS) $(TOOLS) $(HELPERS-y) recurse-all modules
> +
> +mod-obj-m = $(patsubst %.o,%$(DSOSUF),$(filter %.o,$(common-obj-m))) \
> +            $(patsubst %.mo,%$(DSOSUF),$(filter %.mo,$(common-obj-m)))


Why common-obj-m only, what about block-obj-m?

Perhaps adding to mod-obj-m (better name: modules-m) can be done in
unnest-vars?

> +# Generate rules for single file modules (%.so: %.o).
> +$(foreach o,$(filter %.o,$(common-obj-m)),$(eval \
> +	$(patsubst %.o,%.so,$o): $o ))

If you subst %.o to %.mo, you can use the same set of rules for both cases.

> +# For multi file modules, dependencies should be listed explicitly in
> +# Makefile.objs as
> +#     $(obj)/foo.mo-obj := $(obj)/bar.o $(obj)/biz.o

Why not

$(obj)/foo.mo: $(obj)/bar.o $(obj)/biz.o

?

> +$(foreach o,$(filter %.mo,$(mod-obj-m)),$(eval \
> +	$o: $($o-obj)))
> +
> +%.mo:
> +	$(if $(BUILD_DYNAMIC), \
> +		$(call quiet-command,$(CC) $(sort $^) -shared -o $@,"  LD[M] $(TARGET_DIR)$@"), \
> +		$(call quiet-command,$(AR) rcs $@ $(sort $^),"  AR    $(TARGET_DIR)$@"))

I think we can always build modules dynamically.  If the
module/no-module configure option decides whether an object moves
between *-obj-y and *-obj-m, statically-linked modules will just go on
the linker command line with no need for $(AR) or
--whole-archive/--no-whole-archive.

I'm missing where is the .so built (or I guess it can just be
hard-linked?) from the .mo file.

IIRC -shared is not portable to Darwin.  Darwin has separate file
formats for dynamic libraries (.dylib) and loadable modules (.so), so it
needs "-bundle" instad.  All this screams "just use libtool"...

> +
> +
> +modules: $(mod-obj-m)
> +modules: BUILD_DYNAMIC = 1
> +modules: QEMU_CFLAGS += -shared -fPIC

-shared is not needed here, only -fPIC.  Again, libtool would abstract
this nicely.  But it's fine if you prefer to have v3 still without
libtool and only working on ELF systems.

In fact, you probably don't need a special modules target.  You can just
add $(mod-obj-m) to "all".

>  
>  config-host.h: config-host.h-timestamp
>  config-host.h-timestamp: config-host.mak
> @@ -155,7 +178,7 @@ subdir-dtc:dtc/libfdt dtc/tests
>  dtc/%:
>  	mkdir -p $@
>  
> -$(SUBDIR_RULES): libqemuutil.a libqemustub.a $(common-obj-y)
> +$(SUBDIR_RULES): libqemuutil.a libqemustub.a $(common-obj-y) $(common-obj-m)
>  
>  ROMSUBDIR_RULES=$(patsubst %,romsubdir-%, $(ROMS))
>  romsubdir-%:
> @@ -235,6 +258,9 @@ clean:
>  	rm -f qemu-options.def
>  	find . -name '*.[oda]' -type f -exec rm -f {} +
>  	find . -name '*.l[oa]' -type f -exec rm -f {} +
> +	find . -name '*'$(DSOSUF) -type f -exec rm -f {} +
> +	find . -name '*.mo' -type f -exec rm -f {} +
> +
>  	rm -f $(TOOLS) $(HELPERS-y) qemu-ga TAGS cscope.* *.pod *~ */*~
>  	rm -Rf .libs
>  	rm -f qemu-img-cmds.h
> diff --git a/Makefile.objs b/Makefile.objs
> index f46a4cd..8984a20 100644
> --- a/Makefile.objs
> +++ b/Makefile.objs
> @@ -19,6 +19,8 @@ block-obj-y += qemu-coroutine.o qemu-coroutine-lock.o qemu-coroutine-io.o
>  block-obj-y += qemu-coroutine-sleep.o
>  block-obj-y += coroutine-$(CONFIG_COROUTINE_BACKEND).o
>  
> +block-obj-m = block/
> +
>  ifeq ($(CONFIG_VIRTIO)$(CONFIG_VIRTFS)$(CONFIG_PCI),yyy)
>  # Lots of the fsdev/9pcode is pulled in by vl.c via qemu_fsdev_add.
>  # only pull in the actual virtio-9p device if we also enabled virtio.
> @@ -83,6 +85,9 @@ common-obj-$(CONFIG_SMARTCARD_NSS) += $(libcacard-y)
>  
>  common-obj-y += qmp-marshal.o
>  common-obj-y += qmp.o hmp.o
> +
> +common-obj-m = $(block-obj-m)
> +
>  endif
>  
>  ######################################################################
> @@ -121,5 +126,12 @@ nested-vars += \
>  	util-obj-y \
>  	qga-obj-y \
>  	block-obj-y \
> -	common-obj-y
> +	block-obj-m \
> +	common-obj-y \
> +	common-obj-m
> +
>  dummy := $(call unnest-vars)
> +
> +# static linked mods are expanded to .o list
> +dummy := $(call expand-mod-obj,common-obj-y)
> +dummy := $(call expand-mod-obj,block-obj-y)
> diff --git a/configure b/configure
> index af6b048..75abb87 100755
> --- a/configure
> +++ b/configure
> @@ -190,6 +190,7 @@ mingw32="no"
>  gcov="no"
>  gcov_tool="gcov"
>  EXESUF=""
> +DSOSUF=".so"
>  prefix="/usr/local"
>  mandir="\${prefix}/share/man"
>  datadir="\${prefix}/share"
> @@ -584,6 +585,7 @@ fi
>  
>  if test "$mingw32" = "yes" ; then
>    EXESUF=".exe"
> +  DSOSUF=".dll"
>    QEMU_CFLAGS="-DWIN32_LEAN_AND_MEAN -DWINVER=0x501 $QEMU_CFLAGS"
>    # enable C99/POSIX format strings (needs mingw32-runtime 3.15 or later)
>    QEMU_CFLAGS="-D__USE_MINGW_ANSI_STDIO=1 $QEMU_CFLAGS"
> @@ -4175,6 +4177,7 @@ echo "LIBTOOLFLAGS=$LIBTOOLFLAGS" >> $config_host_mak
>  echo "LIBS+=$LIBS" >> $config_host_mak
>  echo "LIBS_TOOLS+=$libs_tools" >> $config_host_mak
>  echo "EXESUF=$EXESUF" >> $config_host_mak
> +echo "DSOSUF=$DSOSUF" >> $config_host_mak
>  echo "LIBS_QGA+=$libs_qga" >> $config_host_mak
>  echo "POD2MAN=$POD2MAN" >> $config_host_mak
>  echo "TRANSLATE_OPT_CFLAGS=$TRANSLATE_OPT_CFLAGS" >> $config_host_mak
> diff --git a/rules.mak b/rules.mak
> index e581d55..0a39499 100644
> --- a/rules.mak
> +++ b/rules.mak
> @@ -58,6 +58,10 @@ endif
>  %.o: %.dtrace
>  	$(call quiet-command,dtrace -o $@ -G -s $<, "  GEN   $(TARGET_DIR)$@")
>  
> +%$(DSOSUF): QEMU_CLFAGS += -shared -fPIC
> +%$(DSOSUF): %.o
> +	$(call quiet-command,$(LD) $< -o $@ -shared,"  LD[M] $(TARGET_DIR)$@")
> +

As mentioned above, I think these four lines are not needed and you can
always go through the "modules" or $(mod-obj-m) targets.  In fact,
CLFAGS sounds dubious. :)

Paolo

>  %$(EXESUF): %.o
>  	$(call LINK,$^)
>  
> @@ -145,3 +149,9 @@ $(shell mkdir -p $(sort $(foreach var,$(nested-vars),$(dir $($(var))))))
>  $(foreach var,$(nested-vars), $(eval \
>    -include $(addsuffix *.d, $(sort $(dir $($(var)))))))
>  endef
> +
> +define expand-mod-obj
> +$(eval pref = $(if $(obj-base),$(obj-base)/,))
> +$(eval t = $(foreach o,$($1),$(if $($(pref)$o-obj),$($(pref)$o-obj),$o)))
> +$(eval $1 = $t)
> +endef
> 

Re: [Qemu-devel] [RFC PATCH v2 2/6] rule.mak: allow per object cflags and libs

[Michael Tokarev]

06.09.2013 11:28, Fam Zheng wrote:
> Adds extract-libs in LINK to expand any "per object libs", the syntax to define
> such a libs options is like:
> 
>         $(obj)/curl.o-libs = $(CURL_LIBS)
> 
> in block/Makefile.objs.
> 
> Similarly,
> 
>         $(obj)foo.o-cflags = $(FOO_CFLAGS)
> 
> is also supported.

Please note the UNsimilarity of -libs and -cflags --
one is with slash and another is without.  Is it just
the patch comment?

Thanks,

/mjt

Re: [Qemu-devel] [RFC PATCH v2 2/6] rule.mak: allow per object cflags and libs

[Fam Zheng]

On Fri, 09/06 14:42, Michael Tokarev wrote:
> 06.09.2013 11:28, Fam Zheng wrote:
> > Adds extract-libs in LINK to expand any "per object libs", the syntax to define
> > such a libs options is like:
> > 
> >         $(obj)/curl.o-libs = $(CURL_LIBS)
> > 
> > in block/Makefile.objs.
> > 
> > Similarly,
> > 
> >         $(obj)foo.o-cflags = $(FOO_CFLAGS)
> > 
> > is also supported.
> 
> Please note the UNsimilarity of -libs and -cflags --
> one is with slash and another is without.  Is it just
> the patch comment?
> 
It's a typo in the commit message. I will fix it.

Thanks,

Fam

Re: [Qemu-devel] [RFC PATCH v2 3/6] Makefile: introduce common-obj-m and block-obj-m for DSO

[Fam Zheng]

On Fri, 09/06 12:09, Paolo Bonzini wrote:
> Il 06/09/2013 09:28, Fam Zheng ha scritto:
> > Add necessary rules and flags for shared object generation.
> > $(common-obj-m) will include $(block-obj-m), like $(common-obj-y) does
> > for $(block-obj-y). The new rules introduced here are:
> > 
> > 0) For all %.so compiling:
> > 
> >     QEMU_CFLAGS += -shared -fPIC
> > 
> > 1) %.o in $(common-obj-m) is compiled to %.o, with "QEMU_CFLAGS +=
> > -shared -fPIC". Then linked to %.so.
> > 
> > 2) %.mo in $(common-obj-m) is the placeholder for %.so for pattern
> > matching in Makefile. It's linked to "-shared" with all its dependencies
> > (multiple *.o) as input. Which means the list of depended objects must
> > be ruled out in each sub-Makefile.objs with an variable:
> > 
> >     $(obj)/foo.mo-obj := $(addprefix $(obj)/,bar.o baz.o qux.o)
> > 
> > Notice that $(obj)/ is required for both target and dependency in the
> > rule. DSO suffix (.so) is configure variable (.dll for Windows).
> 
> Some kinks to iron, but this is really well-architected.  You took all
> the best parts of mjt's patches and fixed almost all the ugly ones.  Kudos!
> 
> > Signed-off-by: Fam Zheng <famz@redhat.com>
> > ---
> >  Makefile      | 32 +++++++++++++++++++++++++++++---
> >  Makefile.objs | 14 +++++++++++++-
> >  configure     |  3 +++
> >  rules.mak     | 10 ++++++++++
> >  4 files changed, 55 insertions(+), 4 deletions(-)
> > 
> > diff --git a/Makefile b/Makefile
> > index 806946e..cf47ea9 100644
> > --- a/Makefile
> > +++ b/Makefile
> > @@ -56,7 +56,7 @@ Makefile: ;
> >  configure: ;
> >  
> >  .PHONY: all clean cscope distclean dvi html info install install-doc \
> > -	pdf recurse-all speed test dist
> > +	pdf recurse-all speed test dist modules
> >  
> >  $(call set-vpath, $(SRC_PATH))
> >  
> > @@ -121,7 +121,30 @@ ifeq ($(CONFIG_SMARTCARD_NSS),y)
> >  include $(SRC_PATH)/libcacard/Makefile
> >  endif
> >  
> > -all: $(DOCS) $(TOOLS) $(HELPERS-y) recurse-all
> > +all: $(DOCS) $(TOOLS) $(HELPERS-y) recurse-all modules
> > +
> > +mod-obj-m = $(patsubst %.o,%$(DSOSUF),$(filter %.o,$(common-obj-m))) \
> > +            $(patsubst %.mo,%$(DSOSUF),$(filter %.mo,$(common-obj-m)))
> 
> 
> Why common-obj-m only, what about block-obj-m?
> 
Because common-obj-m = $(block-obj-m), in Makefile.objs below.

> Perhaps adding to mod-obj-m (better name: modules-m) can be done in
> unnest-vars?

It looks more straightforward for me to do here, and it's used very locally.

> 
> > +# Generate rules for single file modules (%.so: %.o).
> > +$(foreach o,$(filter %.o,$(common-obj-m)),$(eval \
> > +	$(patsubst %.o,%.so,$o): $o ))
> 
> If you subst %.o to %.mo, you can use the same set of rules for both cases.
> 
> > +# For multi file modules, dependencies should be listed explicitly in
> > +# Makefile.objs as
> > +#     $(obj)/foo.mo-obj := $(obj)/bar.o $(obj)/biz.o
> 
> Why not
> 
> $(obj)/foo.mo: $(obj)/bar.o $(obj)/biz.o
> 
> ?
> 
Because I don't know how to expand foo.mo to bar.o and biz.o: I expand "foo.mo"
to "bar.o biz.o" in the link command line, to skip creating to foo.mo, or
libfoo.a, if it's to be linked static:

    block-obj-y += foo.mo

That's for avoiding ar and ln -r.

> > +$(foreach o,$(filter %.mo,$(mod-obj-m)),$(eval \
> > +	$o: $($o-obj)))
> > +
> > +%.mo:
> > +	$(if $(BUILD_DYNAMIC), \
> > +		$(call quiet-command,$(CC) $(sort $^) -shared -o $@,"  LD[M] $(TARGET_DIR)$@"), \
> > +		$(call quiet-command,$(AR) rcs $@ $(sort $^),"  AR    $(TARGET_DIR)$@"))
> 
> I think we can always build modules dynamically.  If the
> module/no-module configure option decides whether an object moves
> between *-obj-y and *-obj-m, statically-linked modules will just go on
> the linker command line with no need for $(AR) or
> --whole-archive/--no-whole-archive.
> 
I don't understand, do you mean a "cc -shared" output can be statically linked
into a executable?

> I'm missing where is the .so built (or I guess it can just be
> hard-linked?) from the .mo file.
> 
> IIRC -shared is not portable to Darwin.  Darwin has separate file
> formats for dynamic libraries (.dylib) and loadable modules (.so), so it
> needs "-bundle" instad.  All this screams "just use libtool"...
> 
> > +
> > +
> > +modules: $(mod-obj-m)
> > +modules: BUILD_DYNAMIC = 1
> > +modules: QEMU_CFLAGS += -shared -fPIC
> 
> -shared is not needed here, only -fPIC.  Again, libtool would abstract
> this nicely.  But it's fine if you prefer to have v3 still without
> libtool and only working on ELF systems.
> 
> In fact, you probably don't need a special modules target.  You can just
> add $(mod-obj-m) to "all".
> 
> >  
> >  config-host.h: config-host.h-timestamp
> >  config-host.h-timestamp: config-host.mak
> > @@ -155,7 +178,7 @@ subdir-dtc:dtc/libfdt dtc/tests
> >  dtc/%:
> >  	mkdir -p $@
> >  
> > -$(SUBDIR_RULES): libqemuutil.a libqemustub.a $(common-obj-y)
> > +$(SUBDIR_RULES): libqemuutil.a libqemustub.a $(common-obj-y) $(common-obj-m)
> >  
> >  ROMSUBDIR_RULES=$(patsubst %,romsubdir-%, $(ROMS))
> >  romsubdir-%:
> > @@ -235,6 +258,9 @@ clean:
> >  	rm -f qemu-options.def
> >  	find . -name '*.[oda]' -type f -exec rm -f {} +
> >  	find . -name '*.l[oa]' -type f -exec rm -f {} +
> > +	find . -name '*'$(DSOSUF) -type f -exec rm -f {} +
> > +	find . -name '*.mo' -type f -exec rm -f {} +
> > +
> >  	rm -f $(TOOLS) $(HELPERS-y) qemu-ga TAGS cscope.* *.pod *~ */*~
> >  	rm -Rf .libs
> >  	rm -f qemu-img-cmds.h
> > diff --git a/Makefile.objs b/Makefile.objs
> > index f46a4cd..8984a20 100644
> > --- a/Makefile.objs
> > +++ b/Makefile.objs
> > @@ -19,6 +19,8 @@ block-obj-y += qemu-coroutine.o qemu-coroutine-lock.o qemu-coroutine-io.o
> >  block-obj-y += qemu-coroutine-sleep.o
> >  block-obj-y += coroutine-$(CONFIG_COROUTINE_BACKEND).o
> >  
> > +block-obj-m = block/
> > +
> >  ifeq ($(CONFIG_VIRTIO)$(CONFIG_VIRTFS)$(CONFIG_PCI),yyy)
> >  # Lots of the fsdev/9pcode is pulled in by vl.c via qemu_fsdev_add.
> >  # only pull in the actual virtio-9p device if we also enabled virtio.
> > @@ -83,6 +85,9 @@ common-obj-$(CONFIG_SMARTCARD_NSS) += $(libcacard-y)
> >  
> >  common-obj-y += qmp-marshal.o
> >  common-obj-y += qmp.o hmp.o
> > +
> > +common-obj-m = $(block-obj-m)
> > +
> >  endif
> >  
> >  ######################################################################
> > @@ -121,5 +126,12 @@ nested-vars += \
> >  	util-obj-y \
> >  	qga-obj-y \
> >  	block-obj-y \
> > -	common-obj-y
> > +	block-obj-m \
> > +	common-obj-y \
> > +	common-obj-m
> > +
> >  dummy := $(call unnest-vars)
> > +
> > +# static linked mods are expanded to .o list
> > +dummy := $(call expand-mod-obj,common-obj-y)
> > +dummy := $(call expand-mod-obj,block-obj-y)
> > diff --git a/configure b/configure
> > index af6b048..75abb87 100755
> > --- a/configure
> > +++ b/configure
> > @@ -190,6 +190,7 @@ mingw32="no"
> >  gcov="no"
> >  gcov_tool="gcov"
> >  EXESUF=""
> > +DSOSUF=".so"
> >  prefix="/usr/local"
> >  mandir="\${prefix}/share/man"
> >  datadir="\${prefix}/share"
> > @@ -584,6 +585,7 @@ fi
> >  
> >  if test "$mingw32" = "yes" ; then
> >    EXESUF=".exe"
> > +  DSOSUF=".dll"
> >    QEMU_CFLAGS="-DWIN32_LEAN_AND_MEAN -DWINVER=0x501 $QEMU_CFLAGS"
> >    # enable C99/POSIX format strings (needs mingw32-runtime 3.15 or later)
> >    QEMU_CFLAGS="-D__USE_MINGW_ANSI_STDIO=1 $QEMU_CFLAGS"
> > @@ -4175,6 +4177,7 @@ echo "LIBTOOLFLAGS=$LIBTOOLFLAGS" >> $config_host_mak
> >  echo "LIBS+=$LIBS" >> $config_host_mak
> >  echo "LIBS_TOOLS+=$libs_tools" >> $config_host_mak
> >  echo "EXESUF=$EXESUF" >> $config_host_mak
> > +echo "DSOSUF=$DSOSUF" >> $config_host_mak
> >  echo "LIBS_QGA+=$libs_qga" >> $config_host_mak
> >  echo "POD2MAN=$POD2MAN" >> $config_host_mak
> >  echo "TRANSLATE_OPT_CFLAGS=$TRANSLATE_OPT_CFLAGS" >> $config_host_mak
> > diff --git a/rules.mak b/rules.mak
> > index e581d55..0a39499 100644
> > --- a/rules.mak
> > +++ b/rules.mak
> > @@ -58,6 +58,10 @@ endif
> >  %.o: %.dtrace
> >  	$(call quiet-command,dtrace -o $@ -G -s $<, "  GEN   $(TARGET_DIR)$@")
> >  
> > +%$(DSOSUF): QEMU_CLFAGS += -shared -fPIC
> > +%$(DSOSUF): %.o
> > +	$(call quiet-command,$(LD) $< -o $@ -shared,"  LD[M] $(TARGET_DIR)$@")
> > +
> 
> As mentioned above, I think these four lines are not needed and you can
> always go through the "modules" or $(mod-obj-m) targets.  In fact,
> CLFAGS sounds dubious. :)
> 
> Paolo
> 
> >  %$(EXESUF): %.o
> >  	$(call LINK,$^)
> >  
> > @@ -145,3 +149,9 @@ $(shell mkdir -p $(sort $(foreach var,$(nested-vars),$(dir $($(var))))))
> >  $(foreach var,$(nested-vars), $(eval \
> >    -include $(addsuffix *.d, $(sort $(dir $($(var)))))))
> >  endef
> > +
> > +define expand-mod-obj
> > +$(eval pref = $(if $(obj-base),$(obj-base)/,))
> > +$(eval t = $(foreach o,$($1),$(if $($(pref)$o-obj),$($(pref)$o-obj),$o)))
> > +$(eval $1 = $t)
> > +endef
> > 
> 

Re: [Qemu-devel] [RFC PATCH v2 3/6] Makefile: introduce common-obj-m and block-obj-m for DSO

[Paolo Bonzini]

Il 06/09/2013 13:47, Fam Zheng ha scritto:
> On Fri, 09/06 12:09, Paolo Bonzini wrote:
>> Il 06/09/2013 09:28, Fam Zheng ha scritto:
>>> Add necessary rules and flags for shared object generation.
>>> $(common-obj-m) will include $(block-obj-m), like $(common-obj-y) does
>>> for $(block-obj-y). The new rules introduced here are:
>>>
>>> 0) For all %.so compiling:
>>>
>>>     QEMU_CFLAGS += -shared -fPIC
>>>
>>> 1) %.o in $(common-obj-m) is compiled to %.o, with "QEMU_CFLAGS +=
>>> -shared -fPIC". Then linked to %.so.
>>>
>>> 2) %.mo in $(common-obj-m) is the placeholder for %.so for pattern
>>> matching in Makefile. It's linked to "-shared" with all its dependencies
>>> (multiple *.o) as input. Which means the list of depended objects must
>>> be ruled out in each sub-Makefile.objs with an variable:
>>>
>>>     $(obj)/foo.mo-obj := $(addprefix $(obj)/,bar.o baz.o qux.o)
>>>
>>> Notice that $(obj)/ is required for both target and dependency in the
>>> rule. DSO suffix (.so) is configure variable (.dll for Windows).
>>
>> Some kinks to iron, but this is really well-architected.  You took all
>> the best parts of mjt's patches and fixed almost all the ugly ones.  Kudos!
>>
>>> Signed-off-by: Fam Zheng <famz@redhat.com>
>>> ---
>>>  Makefile      | 32 +++++++++++++++++++++++++++++---
>>>  Makefile.objs | 14 +++++++++++++-
>>>  configure     |  3 +++
>>>  rules.mak     | 10 ++++++++++
>>>  4 files changed, 55 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/Makefile b/Makefile
>>> index 806946e..cf47ea9 100644
>>> --- a/Makefile
>>> +++ b/Makefile
>>> @@ -56,7 +56,7 @@ Makefile: ;
>>>  configure: ;
>>>  
>>>  .PHONY: all clean cscope distclean dvi html info install install-doc \
>>> -	pdf recurse-all speed test dist
>>> +	pdf recurse-all speed test dist modules
>>>  
>>>  $(call set-vpath, $(SRC_PATH))
>>>  
>>> @@ -121,7 +121,30 @@ ifeq ($(CONFIG_SMARTCARD_NSS),y)
>>>  include $(SRC_PATH)/libcacard/Makefile
>>>  endif
>>>  
>>> -all: $(DOCS) $(TOOLS) $(HELPERS-y) recurse-all
>>> +all: $(DOCS) $(TOOLS) $(HELPERS-y) recurse-all modules
>>> +
>>> +mod-obj-m = $(patsubst %.o,%$(DSOSUF),$(filter %.o,$(common-obj-m))) \
>>> +            $(patsubst %.mo,%$(DSOSUF),$(filter %.mo,$(common-obj-m)))
>>
>>
>> Why common-obj-m only, what about block-obj-m?
>>
> Because common-obj-m = $(block-obj-m), in Makefile.objs below.
> 
>> Perhaps adding to mod-obj-m (better name: modules-m) can be done in
>> unnest-vars?
> 
> It looks more straightforward for me to do here, and it's used very locally.

But it doesn't scale too well, does it?  There's no particular reason 
why all -m variables would be included in common-obj-m.  In fact, block-
obj-y/block-obj-m are the only remaining case of one variable including 
another.  In another review I even proposed eliminating this exception.

>>> +# Generate rules for single file modules (%.so: %.o).
>>> +$(foreach o,$(filter %.o,$(common-obj-m)),$(eval \
>>> +	$(patsubst %.o,%.so,$o): $o ))
>>
>> If you subst %.o to %.mo, you can use the same set of rules for both cases.
>>
>>> +# For multi file modules, dependencies should be listed explicitly in
>>> +# Makefile.objs as
>>> +#     $(obj)/foo.mo-obj := $(obj)/bar.o $(obj)/biz.o
>>
>> Why not
>>
>> $(obj)/foo.mo: $(obj)/bar.o $(obj)/biz.o
>>
>> ?
>>
> Because I don't know how to expand foo.mo to bar.o and biz.o: I expand "foo.mo"
> to "bar.o biz.o" in the link command line, to skip creating to foo.mo, or
> libfoo.a, if it's to be linked static:
> 
>     block-obj-y += foo.mo
> 
> That's for avoiding ar and ln -r.

Ah, I see now.  See below for an idea (if it works).

>>> +$(foreach o,$(filter %.mo,$(mod-obj-m)),$(eval \
>>> +	$o: $($o-obj)))
>>> +
>>> +%.mo:
>>> +	$(if $(BUILD_DYNAMIC), \
>>> +		$(call quiet-command,$(CC) $(sort $^) -shared -o $@,"  LD[M] $(TARGET_DIR)$@"), \
>>> +		$(call quiet-command,$(AR) rcs $@ $(sort $^),"  AR    $(TARGET_DIR)$@"))
>>
>> I think we can always build modules dynamically.  If the
>> module/no-module configure option decides whether an object moves
>> between *-obj-y and *-obj-m, statically-linked modules will just go on
>> the linker command line with no need for $(AR) or
>> --whole-archive/--no-whole-archive.
>>
> I don't understand, do you mean a "cc -shared" output can be statically linked
> into a executable?

So if I understand correctly the .mo file is never used for a 
statically-linked module?  So the "ar" doesn't matter as things stand

Perhaps you could just use .mo file as a placeholder that holds the
module's list of dependencies, no matter if it is shared or static:

%.mo:
	$(call quiet-command,echo $(sort $^) > $@,"  GEN    $(TARGET_DIR_$@"))

In the LINK rule include the list from all .mo files:

	$(sort $(filter %.o, $1)) \
	$(shell cat $(filter %.mo,$^)) \
	$(filter-out %.o %.mo,$^))

And the rule for shared objects would be simply:

%.$(DSOSUF): QEMU_LDFLAGS += -shared
%.$(DSOSUF): %.mo
	$(call LINK,$^)

This would remove the need for the $i-obj variables.

Paolo

Re: [Qemu-devel] [RFC PATCH v2 1/6] make.rule: fix $(obj) to a real relative path

[Lluís Vilanova]

Fam Zheng writes:
[...]
> Because $(obj) here is './block', instead of '../block'. This doesn't
> hurt compiling because we basically build all .o from top Makefile,
> before entering Makefile.target, but it will affact arriving per-object
> libs support.

I'm curious. What's the reason to not use recursive make in QEMU?


Thanks,
  Lluis

Re: [Qemu-devel] [RFC PATCH v2 1/6] make.rule: fix $(obj) to a real relative path

[Fam Zheng]

On Fri, 09/06 20:19, Lluís Vilanova wrote:
> Fam Zheng writes:
> [...]
> > Because $(obj) here is './block', instead of '../block'. This doesn't
> > hurt compiling because we basically build all .o from top Makefile,
> > before entering Makefile.target, but it will affact arriving per-object
> > libs support.
> 
> I'm curious. What's the reason to not use recursive make in QEMU?
> 
I don't know the answer, Paolo?

Fam

Re: [Qemu-devel] [RFC PATCH v2 3/6] Makefile: introduce common-obj-m and block-obj-m for DSO

[Fam Zheng]

On Fri, 09/06 14:11, Paolo Bonzini wrote:
> Il 06/09/2013 13:47, Fam Zheng ha scritto:
> > On Fri, 09/06 12:09, Paolo Bonzini wrote:
> >> Il 06/09/2013 09:28, Fam Zheng ha scritto:
> >>> Add necessary rules and flags for shared object generation.
> >>> $(common-obj-m) will include $(block-obj-m), like $(common-obj-y) does
> >>> for $(block-obj-y). The new rules introduced here are:
> >>>
> >>> 0) For all %.so compiling:
> >>>
> >>>     QEMU_CFLAGS += -shared -fPIC
> >>>
> >>> 1) %.o in $(common-obj-m) is compiled to %.o, with "QEMU_CFLAGS +=
> >>> -shared -fPIC". Then linked to %.so.
> >>>
> >>> 2) %.mo in $(common-obj-m) is the placeholder for %.so for pattern
> >>> matching in Makefile. It's linked to "-shared" with all its dependencies
> >>> (multiple *.o) as input. Which means the list of depended objects must
> >>> be ruled out in each sub-Makefile.objs with an variable:
> >>>
> >>>     $(obj)/foo.mo-obj := $(addprefix $(obj)/,bar.o baz.o qux.o)
> >>>
> >>> Notice that $(obj)/ is required for both target and dependency in the
> >>> rule. DSO suffix (.so) is configure variable (.dll for Windows).
> >>
> >> Some kinks to iron, but this is really well-architected.  You took all
> >> the best parts of mjt's patches and fixed almost all the ugly ones.  Kudos!
> >>
> >>> Signed-off-by: Fam Zheng <famz@redhat.com>
> >>> ---
> >>>  Makefile      | 32 +++++++++++++++++++++++++++++---
> >>>  Makefile.objs | 14 +++++++++++++-
> >>>  configure     |  3 +++
> >>>  rules.mak     | 10 ++++++++++
> >>>  4 files changed, 55 insertions(+), 4 deletions(-)
> >>>
> >>> diff --git a/Makefile b/Makefile
> >>> index 806946e..cf47ea9 100644
> >>> --- a/Makefile
> >>> +++ b/Makefile
> >>> @@ -56,7 +56,7 @@ Makefile: ;
> >>>  configure: ;
> >>>  
> >>>  .PHONY: all clean cscope distclean dvi html info install install-doc \
> >>> -	pdf recurse-all speed test dist
> >>> +	pdf recurse-all speed test dist modules
> >>>  
> >>>  $(call set-vpath, $(SRC_PATH))
> >>>  
> >>> @@ -121,7 +121,30 @@ ifeq ($(CONFIG_SMARTCARD_NSS),y)
> >>>  include $(SRC_PATH)/libcacard/Makefile
> >>>  endif
> >>>  
> >>> -all: $(DOCS) $(TOOLS) $(HELPERS-y) recurse-all
> >>> +all: $(DOCS) $(TOOLS) $(HELPERS-y) recurse-all modules
> >>> +
> >>> +mod-obj-m = $(patsubst %.o,%$(DSOSUF),$(filter %.o,$(common-obj-m))) \
> >>> +            $(patsubst %.mo,%$(DSOSUF),$(filter %.mo,$(common-obj-m)))
> >>
> >>
> >> Why common-obj-m only, what about block-obj-m?
> >>
> > Because common-obj-m = $(block-obj-m), in Makefile.objs below.
> > 
> >> Perhaps adding to mod-obj-m (better name: modules-m) can be done in
> >> unnest-vars?
> > 
> > It looks more straightforward for me to do here, and it's used very locally.
> 
> But it doesn't scale too well, does it?  There's no particular reason 
> why all -m variables would be included in common-obj-m.  In fact, block-
> obj-y/block-obj-m are the only remaining case of one variable including 
> another.  In another review I even proposed eliminating this exception.
> 
> >>> +# Generate rules for single file modules (%.so: %.o).
> >>> +$(foreach o,$(filter %.o,$(common-obj-m)),$(eval \
> >>> +	$(patsubst %.o,%.so,$o): $o ))
> >>
> >> If you subst %.o to %.mo, you can use the same set of rules for both cases.
> >>
> >>> +# For multi file modules, dependencies should be listed explicitly in
> >>> +# Makefile.objs as
> >>> +#     $(obj)/foo.mo-obj := $(obj)/bar.o $(obj)/biz.o
> >>
> >> Why not
> >>
> >> $(obj)/foo.mo: $(obj)/bar.o $(obj)/biz.o
> >>
> >> ?
> >>
> > Because I don't know how to expand foo.mo to bar.o and biz.o: I expand "foo.mo"
> > to "bar.o biz.o" in the link command line, to skip creating to foo.mo, or
> > libfoo.a, if it's to be linked static:
> > 
> >     block-obj-y += foo.mo
> > 
> > That's for avoiding ar and ln -r.
> 
> Ah, I see now.  See below for an idea (if it works).
> 
> >>> +$(foreach o,$(filter %.mo,$(mod-obj-m)),$(eval \
> >>> +	$o: $($o-obj)))
> >>> +
> >>> +%.mo:
> >>> +	$(if $(BUILD_DYNAMIC), \
> >>> +		$(call quiet-command,$(CC) $(sort $^) -shared -o $@,"  LD[M] $(TARGET_DIR)$@"), \
> >>> +		$(call quiet-command,$(AR) rcs $@ $(sort $^),"  AR    $(TARGET_DIR)$@"))
> >>
> >> I think we can always build modules dynamically.  If the
> >> module/no-module configure option decides whether an object moves
> >> between *-obj-y and *-obj-m, statically-linked modules will just go on
> >> the linker command line with no need for $(AR) or
> >> --whole-archive/--no-whole-archive.
> >>
> > I don't understand, do you mean a "cc -shared" output can be statically linked
> > into a executable?
> 
> So if I understand correctly the .mo file is never used for a 
> statically-linked module?  So the "ar" doesn't matter as things stand
> 
> Perhaps you could just use .mo file as a placeholder that holds the
> module's list of dependencies, no matter if it is shared or static:
> 
> %.mo:
> 	$(call quiet-command,echo $(sort $^) > $@,"  GEN    $(TARGET_DIR_$@"))
> 
> In the LINK rule include the list from all .mo files:
> 
> 	$(sort $(filter %.o, $1)) \
> 	$(shell cat $(filter %.mo,$^)) \
> 	$(filter-out %.o %.mo,$^))
> 
> And the rule for shared objects would be simply:
> 
> %.$(DSOSUF): QEMU_LDFLAGS += -shared
> %.$(DSOSUF): %.mo
> 	$(call LINK,$^)
> 
> This would remove the need for the $i-obj variables.
> 
Actually I would like a try to keep $i-{obj,cflags,libs}:

    foo-obj := bar.o biz.o
    foo-libs := $(FOO_LIBS)
    foo-cflags := $(FOO_CFLAGS)

getting rid of all the $(obj)/'s and expand them in the toplevel unnest magic
(because we know foo.mo is contained in local $(block-obj-y) so it's all
trackable).

If this idea can't work out, I'll use your suggested way.

Thanks,

Fam

Re: [Qemu-devel] [RFC PATCH v2 1/6] make.rule: fix $(obj) to a real relative path

[Paolo Bonzini]

Il 09/09/2013 03:34, Fam Zheng ha scritto:
> On Fri, 09/06 20:19, Lluís Vilanova wrote:
>> Fam Zheng writes:
>> [...]
>>> Because $(obj) here is './block', instead of '../block'. This doesn't
>>> hurt compiling because we basically build all .o from top Makefile,
>>> before entering Makefile.target, but it will affact arriving per-object
>>> libs support.
>>
>> I'm curious. What's the reason to not use recursive make in QEMU?
>>
> I don't know the answer, Paolo?

It predates my involvement by a long time, so I don't know.

But my guess is that whenever directories are not present in the build
tree (e.g. i386-softmmu/hw) we have to create the Makefile in the
configure script.  Thus a heavily declarative Makefile style works better.

Paolo

Re: [Qemu-devel] [RFC PATCH v2 3/6] Makefile: introduce common-obj-m and block-obj-m for DSO

[Paolo Bonzini]

Il 09/09/2013 04:26, Fam Zheng ha scritto:
> Actually I would like a try to keep $i-{obj,cflags,libs}:
> 
>     foo-obj := bar.o biz.o
>     foo-libs := $(FOO_LIBS)
>     foo-cflags := $(FOO_CFLAGS)
> 
> getting rid of all the $(obj)/'s and expand them in the toplevel unnest magic
> (because we know foo.mo is contained in local $(block-obj-y) so it's all
> trackable).
> 
> If this idea can't work out, I'll use your suggested way.

Yes, either way works (i.e. as long as it's consistent).

Paolo

Re: [Qemu-devel] [RFC PATCH v2 1/6] make.rule: fix $(obj) to a real relative path

[Peter Maydell]

On 6 September 2013 18:19, Lluís Vilanova <vilanova@ac.upc.edu> wrote:
> Fam Zheng writes:
> [...]
>> Because $(obj) here is './block', instead of '../block'. This doesn't
>> hurt compiling because we basically build all .o from top Makefile,
>> before entering Makefile.target, but it will affact arriving per-object
>> libs support.
>
> I'm curious. What's the reason to not use recursive make in QEMU?

The classic paper is "Recursive make considered harmful":
http://aegis.sourceforge.net/auug97.pdf

-- PMM