Only compile the hypervisor with -Wdeclaration-after-statement

Right now, all tools and hypervisor will be complied with the option
-Wdeclaration-after-statement. While most of the code in the hypervisor
is controlled by us, for tools we may import external libraries.

The build will fail if one of them are using the construct we are
trying to prevent. This is the case when building against Python 3.12
and Yocto:

| In file included from /srv/storage/alex/yocto/build-virt/tmp/work/core2-64-poky-linux/xen-tools/4.17+stable/recipe-sysroot/usr/include/python3.12/Python.h:44,
|                  from xen/lowlevel/xc/xc.c:8:
| /srv/storage/alex/yocto/build-virt/tmp/work/core2-64-poky-linux/xen-tools/4.17+stable/recipe-sysroot/usr/include/python3.12/object.h: In function 'Py_SIZE':
| /srv/storage/alex/yocto/build-virt/tmp/work/core2-64-poky-linux/xen-tools/4.17+stable/recipe-sysroot/usr/include/python3.12/object.h:233:5: error: ISO C90 forbids mixed declarations and code [-Werror=declaration-after-statement]
|   233 |     PyVarObject *var_ob = _PyVarObject_CAST(ob);
|       |     ^~~~~~~~~~~
| In file included from /srv/storage/alex/yocto/build-virt/tmp/work/core2-64-poky-linux/xen-tools/4.17+stable/recipe-sysroot/usr/include/python3.12/Python.h:53:
| /srv/storage/alex/yocto/build-virt/tmp/work/core2-64-poky-linux/xen-tools/4.17+stable/recipe-sysroot/usr/include/python3.12/cpython/longintrepr.h: In function '_PyLong_CompactValue':
| /srv/storage/alex/yocto/build-virt/tmp/work/core2-64-poky-linux/xen-tools/4.17+stable/recipe-sysroot/usr/include/python3.12/cpython/longintrepr.h:121:5: error: ISO C90 forbids mixed declarations and code [-Werror=declaration-after-statement]
|   121 |     Py_ssize_t sign = 1 - (op->long_value.lv_tag & _PyLong_SIGN_MASK);
|       |     ^~~~~~~~~~
| cc1: all warnings being treated as errors

Looking at the tools directory, a fair few directory already add
-Wno-declaration-after-statement to inhibit the default behavior.

We have always build the hypervisor with the flag, so for now remove
only the flag for anything but the hypervisor. We can decide at later
time whether we want to relax.

Also remove the -Wno-declaration-after-statement in some subdirectory
as the flag is now unnecessary.

Part of the commit message was take from Alexander's first proposal:

Link: https://lore.kernel.org/xen-devel/20231128174729.3880113-1-alex@linutronix.de/
Reported-by: Alexander Kanavin <alex@linutronix.de>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Tested-by: Jason Andryuk <jandryuk@gmail.com>
Signed-off-by: Julien Grall <jgrall@amazon.com>
xen/hypervisor: Don't use cc-option-add for -Wdeclaration-after-statement

Per Andrew's comment in [1] all the compilers we support should
recognize the flag.

I forgot to address the comment while committing.

[1] fcf00090-304a-49f7-8a61-a54347e90a3b@citrix.com

Signed-off-by: Julien Grall <jgrall@amazon.com>
master commit: 40be6307ec005539635e7b8fcef67e989dc441f6
master date: 2023-12-06 19:12:40 +0000
master commit: d4bfd3899886d0fbe259c20660dadb1e00170f2d
master date: 2023-12-06 19:19:59 +0000

diff --git a/Config.mk b/Config.mk
index 29b0d1e12a327cdb11c9b170240a7472043b6b52..2a3e16d0bdecc2931897f3320dea46edf41b2419 100644 (file)
--- a/Config.mk
+++ b/Config.mk
@@ -177,8 +177,6 @@ CFLAGS += -std=gnu99
 
 CFLAGS += -Wall -Wstrict-prototypes
 
-$(call cc-option-add,HOSTCFLAGS,HOSTCC,-Wdeclaration-after-statement)
-$(call cc-option-add,CFLAGS,CC,-Wdeclaration-after-statement)
 $(call cc-option-add,CFLAGS,CC,-Wno-unused-but-set-variable)
 $(call cc-option-add,CFLAGS,CC,-Wno-unused-local-typedefs)
 

diff --git a/stubdom/Makefile b/stubdom/Makefile
index 0ddfce1ba2b967e9994648afc0b80e86a0beae2b..888fa20d72a523a654b58c0d2f8ce4c1aa67344a 100644 (file)
--- a/stubdom/Makefile
+++ b/stubdom/Makefile
@@ -245,7 +245,7 @@ tpm_emulator-$(XEN_TARGET_ARCH): tpm_emulator-$(TPMEMU_VERSION).tar.gz
        patch -d $@ -p1 < vtpm-command-duration.patch
        patch -d $@ -p1 < vtpm-tpm_bn_t-addr.patch
        mkdir $@/build
-       cd $@/build; CC=${CC} $(CMAKE) .. -DCMAKE_C_FLAGS:STRING="-std=c99 -DTPM_NO_EXTERN $(TARGET_CPPFLAGS) $(TARGET_CFLAGS) -Wno-declaration-after-statement"
+       cd $@/build; CC=${CC} $(CMAKE) .. -DCMAKE_C_FLAGS:STRING="-std=c99 -DTPM_NO_EXTERN $(TARGET_CPPFLAGS) $(TARGET_CFLAGS)"
        touch $@
 
 TPMEMU_STAMPFILE=$(CROSS_ROOT)/$(GNU_TARGET_ARCH)-xen-elf/lib/libtpm.a

diff --git a/stubdom/vtpmmgr/Makefile b/stubdom/vtpmmgr/Makefile
index 6dae034a07784ebdb50f10fed2f1892eb5e9fa1a..c29bb498381cd0c5f3be9046aeae3bea37da5083 100644 (file)
--- a/stubdom/vtpmmgr/Makefile
+++ b/stubdom/vtpmmgr/Makefile
@@ -17,7 +17,7 @@ OBJS += vtpm_disk.o disk_tpm.o disk_io.o disk_crypto.o disk_read.o disk_write.o
 OBJS += mgmt_authority.o
 
 CFLAGS+=-Werror -Iutil -Icrypto -Itcs
-CFLAGS+=-Wno-declaration-after-statement -Wno-unused-label
+CFLAGS+=-Wno-unused-label
 
 build: $(TARGET)
 $(TARGET): $(OBJS)

diff --git a/tools/libs/light/Makefile b/tools/libs/light/Makefile
index ba4c1b79336f63e8a6ee12f97bd949d533409eff..37e4d167098690b1d40d9fb07a185c0950a4cc83 100644 (file)
--- a/tools/libs/light/Makefile
+++ b/tools/libs/light/Makefile
@@ -38,8 +38,7 @@ vpath static_tables.c $(ACPI_PATH)/
 
 OBJS-$(CONFIG_X86) += $(ACPI_OBJS)
 
-CFLAGS += -Wno-format-zero-length -Wmissing-declarations \
-       -Wno-declaration-after-statement -Wformat-nonliteral
+CFLAGS += -Wno-format-zero-length -Wmissing-declarations -Wformat-nonliteral
 
 CFLAGS-$(CONFIG_X86) += -DCONFIG_PCI_SUPP_LEGACY_IRQ
 

diff --git a/tools/libs/util/Makefile b/tools/libs/util/Makefile
index c3b21875dcd8eb3b8cd773799476dd9419d8029e..936ec90a31534f4deaca124af7ca0c99c360a500 100644 (file)
--- a/tools/libs/util/Makefile
+++ b/tools/libs/util/Makefile
@@ -9,8 +9,7 @@ OBJS-y += libxlu_disk.o
 OBJS-y += libxlu_vif.o
 OBJS-y += libxlu_pci.o
 
-CFLAGS += -Wno-format-zero-length -Wmissing-declarations \
-       -Wno-declaration-after-statement -Wformat-nonliteral
+CFLAGS += -Wno-format-zero-length -Wmissing-declarations -Wformat-nonliteral
 CFLAGS += $(CFLAGS_libxenctrl)
 
 CFLAGS += $(PTHREAD_CFLAGS)

diff --git a/tools/tests/depriv/Makefile b/tools/tests/depriv/Makefile
index 7d9e3b01bbd45013966931f167330396a64b982d..5404a12f4780b1f223ae2fca3eca075b630407f4 100644 (file)
--- a/tools/tests/depriv/Makefile
+++ b/tools/tests/depriv/Makefile
@@ -1,8 +1,6 @@
 XEN_ROOT=$(CURDIR)/../../..
 include $(XEN_ROOT)/tools/Rules.mk
 
-CFLAGS += -Wno-declaration-after-statement
-
 CFLAGS += $(CFLAGS_xeninclude)
 CFLAGS += $(CFLAGS_libxenctrl)
 CFLAGS += $(CFLAGS_libxencall)

diff --git a/tools/xl/Makefile b/tools/xl/Makefile
index 5f7aa5f46c870084be306d02b23def99ca33647f..d742e96a5b3e1b6dae84bf59b4447fae4485666d 100644 (file)
--- a/tools/xl/Makefile
+++ b/tools/xl/Makefile
@@ -5,8 +5,7 @@
 XEN_ROOT = $(CURDIR)/../..
 include $(XEN_ROOT)/tools/Rules.mk
 
-CFLAGS += -Wno-format-zero-length -Wmissing-declarations \
-       -Wno-declaration-after-statement -Wformat-nonliteral
+CFLAGS += -Wno-format-zero-length -Wmissing-declarations -Wformat-nonliteral
 CFLAGS += -fPIC
 
 CFLAGS += $(PTHREAD_CFLAGS)

diff --git a/xen/Makefile b/xen/Makefile
index e39290f638237d8f19ca5c6c4271419bfb5c45a0..a92709b43e6339c00abb6da452556cee9114664f 100644 (file)
--- a/xen/Makefile
+++ b/xen/Makefile
@@ -392,6 +392,7 @@ CFLAGS-$(CONFIG_CC_SPLIT_SECTIONS) += -ffunction-sections -fdata-sections
 
 CFLAGS += -nostdinc -fno-builtin -fno-common
 CFLAGS += -Werror -Wredundant-decls -Wno-pointer-arith
+CFLAGS += -Wdeclaration-after-statement
 $(call cc-option-add,CFLAGS,CC,-Wvla)
 CFLAGS += -pipe -D__XEN__ -include $(srctree)/include/xen/config.h
 CFLAGS-$(CONFIG_DEBUG_INFO) += -g