On 2024-09-21 8:55 a.m., Alex Bennée wrote:
Brad Smith <b...@comstyle.com> writes:
contrib/plugins: ensure build does not pick up a system copy of plugin
header
I'm confused because this changes the ordering of the GLIB inclusion. We
shouldn't be including the whole QEMU include path.
That's intentional. The GLIB header paths cannot come before the header path
for the plugin header otherwise it pulls in the older plugin header from the
installed copy of QEMU and breaks. The QEMU include path is necessary
for the plugin header.
cc -O2 -g -I/usr/local/include/glib-2.0
-I/usr/local/lib/glib-2.0/include -I/usr/local/include -fPIC -Wall
-I/home/brad/tmp/qemu/contrib/plugins/../../include/qemu -c -o execlog.o
/home/brad/tmp/qemu/contrib/plugins/execlog.c
/home/brad/tmp/qemu/contrib/plugins/execlog.c:262:41: error: too many
arguments to function call, expected single argument 'insn', have 3
arguments
qemu_plugin_insn_data(insn, &insn_opcode, sizeof(insn_opcode));
~~~~~~~~~~~~~~~~~~~~~ ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/local/include/qemu-plugin.h:407:13: note: 'qemu_plugin_insn_data'
declared here
const void *qemu_plugin_insn_data(const struct qemu_plugin_insn *insn);
^
1 error generated.
How does this fail?
With the ordering of the header path if a copy of QEMU is installed it
will pickup the system copy of the header before the build paths copy
and the build will fail.
Signed-off-by: Brad Smith <b...@comstyle.com>
---
contrib/plugins/Makefile | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/contrib/plugins/Makefile b/contrib/plugins/Makefile
index 05a2a45c5c..52fc390376 100644
--- a/contrib/plugins/Makefile
+++ b/contrib/plugins/Makefile
@@ -41,9 +41,10 @@ SONAMES := $(addsuffix $(SO_SUFFIX),$(addprefix
lib,$(NAMES)))
# The main QEMU uses Glib extensively so it is perfectly fine to use it
# in plugins (which many example do).
-PLUGIN_CFLAGS := $(shell $(PKG_CONFIG) --cflags glib-2.0)
-PLUGIN_CFLAGS += -fPIC -Wall
+GLIB_CFLAGS := $(shell $(PKG_CONFIG) --cflags glib-2.0)
PLUGIN_CFLAGS += -I$(TOP_SRC_PATH)/include/qemu
Not withstanding the fact I've just borrowed bswap.h for a test plugin
maybe we should actually copy qemu-plugin.h to an entirely new location
during the build and then include from there to avoid any other
potential pollutions?
I don't see how that would make any difference, but either way as long
as the header
path ordering is corrected so this new path is not passed last on the
command line
getting the ordering wrong.
+PLUGIN_CFLAGS += $(GLIB_CFLAGS)
+PLUGIN_CFLAGS += -fPIC -Wall
# Helper that honours V=1 so we get some output when compiling
quiet-@ = $(if $(V),,@$(if $1,printf " %-7s %s\n" "$(strip $1)" "$(strip $2)"
&& ))
