configure: integrate Meson in the build system

The Meson build system is integrated in the existing configure/make steps
by invoking Meson from the configure script and converting Meson's build.ninja
rules to an included Makefile.

build.ninja already provides tags/ctags/cscope rules, so they are removed.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Makefile

@@ -49,6 +49,25 @@ git-submodule-update:
 endif
 endif
 
+export NINJA=./ninjatool
+
+# Running meson regenerates both build.ninja and ninjatool, and that is
+# enough to prime the rest of the build.
+ninjatool: build.ninja
+
+# Only needed in case Makefile.ninja does not exist.
+.PHONY: ninja-clean ninja-distclean clean-ctlist
+clean-ctlist:
+ninja-clean::
+ninja-distclean::
+build.ninja: config-host.mak
+
+Makefile.ninja: build.ninja ninjatool
+	./ninjatool -t ninja2make --omit clean dist uninstall < $< > $@
+-include Makefile.ninja
+
+${ninja-targets-c_COMPILER} ${ninja-targets-cpp_COMPILER}: .var.command += -MP
+
 .git-submodule-status: git-submodule-update config-host.mak
 
 # Check that we're not trying to do an out-of-tree build from
@@ -70,7 +89,11 @@ CONFIG_ALL=y
 
 config-host.mak: $(SRC_PATH)/configure $(SRC_PATH)/pc-bios $(SRC_PATH)/VERSION
 	@echo $@ is out-of-date, running configure
-	@./config.status
+	@if test -f meson-private/coredata.dat; then \
+	  ./config.status --skip-meson; \
+	else \
+	  ./config.status; \
+	fi
 
 # Force configure to re-run if the API symbols are updated
 ifeq ($(CONFIG_PLUGIN),y)
@@ -762,7 +785,8 @@ clean-coverage:
 		"CLEAN", "coverage files")
 endif
 
-clean: recurse-clean
+clean: recurse-clean ninja-clean clean-ctlist
+	-test -f ninjatool && ./ninjatool $(if $(V),-v,) -t clean
 # avoid old build problems by removing potentially incorrect old files
 	rm -f config.mak op-i386.h opc-i386.h gen-op-i386.h op-arm.h opc-arm.h gen-op-arm.h
 	rm -f qemu-options.def
@@ -799,7 +823,8 @@ rm -rf $(MANUAL_BUILDDIR)/$1/_static
 rm -f $(MANUAL_BUILDDIR)/$1/objects.inv $(MANUAL_BUILDDIR)/$1/searchindex.js $(MANUAL_BUILDDIR)/$1/*.html
 endef
 
-distclean: clean
+distclean: clean ninja-distclean
+	-test -f ninjatool && ./ninjatool $(if $(V),-v,) -t clean -g
 	rm -f config-host.mak config-host.h* $(DOCS)
 	rm -f tests/tcg/config-*.mak
 	rm -f config-all-devices.mak config-all-disas.mak config.status
@@ -807,6 +832,8 @@ distclean: clean
 	rm -f po/*.mo tests/qemu-iotests/common.env
 	rm -f roms/seabios/config.mak roms/vgabios/config.mak
 	rm -f qemu-plugins-ld.symbols qemu-plugins-ld64.symbols
+	rm -rf meson-private meson-logs meson-info compile_commands.json
+	rm -f Makefile.ninja ninjatool ninjatool.stamp
 	rm -f config.log
 	rm -f linux-headers/asm
 	rm -f docs/version.texi
@@ -933,6 +960,8 @@ ICON_SIZES=16x16 24x24 32x32 48x48 64x64 128x128 256x256 512x512
 install-includedir:
 	$(INSTALL_DIR) "$(DESTDIR)$(includedir)"
 
+# Needed by "meson install"
+export DESTDIR
 install: all $(if $(BUILD_DOCS),install-doc) \
 	install-datadir install-localstatedir install-includedir \
 	$(if $(INSTALL_BLOBS),$(edk2-decompressed)) \
@@ -1006,21 +1035,6 @@ endif
 	done
 	$(INSTALL_DATA) $(BUILD_DIR)/trace-events-all "$(DESTDIR)$(qemu_datadir)/trace-events-all"
 
-.PHONY: ctags
-ctags:
-	rm -f tags
-	find "$(SRC_PATH)" -name '*.[hc]' -exec ctags --append {} +
-
-.PHONY: TAGS
-TAGS:
-	rm -f TAGS
-	find "$(SRC_PATH)" -name '*.[hc]' -exec etags --append {} +
-
-cscope:
-	rm -f "$(SRC_PATH)"/cscope.*
-	find "$(SRC_PATH)/" -name "*.[chsS]" -print | sed 's,^\./,,' > "$(SRC_PATH)/cscope.files"
-	cscope -b -i"$(SRC_PATH)/cscope.files"
-
 # opengl shader programs
 ui/shader/%-vert.h: $(SRC_PATH)/ui/shader/%.vert $(SRC_PATH)/scripts/shaderinclude.pl
 	@mkdir -p $(dir $@)

configure

@@ -552,6 +552,8 @@ fuzzing="no"
 rng_none="no"
 secret_keyring=""
 libdaxctl=""
+meson=""
+skip_meson=no
 
 supported_cpu="no"
 supported_os="no"
@@ -1048,6 +1050,10 @@ for opt do
   ;;
   --sphinx-build=*) sphinx_build="$optarg"
   ;;
+  --skip-meson) skip_meson=yes
+  ;;
+  --meson=*) meson="$optarg"
+  ;;
   --gcov=*) gcov_tool="$optarg"
   ;;
   --smbd=*) smbd="$optarg"
@@ -1813,6 +1819,7 @@ Advanced options (experts only):
   --install=INSTALL        use specified install [$install]
   --python=PYTHON          use specified python [$python]
   --sphinx-build=SPHINX    use specified sphinx-build [$sphinx_build]
+  --meson=MESON            use specified meson [$meson]
   --smbd=SMBD              use specified smbd [$smbd]
   --with-git=GIT           use specified git [$git]
   --static                 enable static build [$static]
@@ -2020,6 +2027,16 @@ python_version=$($python -c 'import sys; print("%d.%d.%d" % (sys.version_info[0]
 # Suppress writing compiled files
 python="$python -B"
 
+if ! has "$meson"
+then
+    error_exit "Meson not found. Use --meson=/path/to/meson"
+fi
+meson=$(command -v $meson)
+
+if ! $python -c 'import pkg_resources' > /dev/null 2>&1; then
+  error_exit "Python setuptools not found"
+fi
+
 # Check that the C compiler works. Doing this here before testing
 # the host CPU ensures that we had a valid CC to autodetect the
 # $cpu var (and we should bail right here if that's not the case).
@@ -6550,13 +6567,13 @@ elif test "$fortify_source" = "yes" ; then
   QEMU_CFLAGS="-U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 $QEMU_CFLAGS"
   debug=no
 fi
-if test "$debug" = "no"; then
-  CFLAGS="-O2 $CFLAGS"
-fi
 if test "$debug_info" = "yes"; then
   CFLAGS="-g $CFLAGS"
   LDFLAGS="-g $LDFLAGS"
 fi
+if test "$debug" = "no"; then
+  CFLAGS="-O2 $CFLAGS"
+fi
 
 case "$ARCH" in
 alpha)
@@ -8001,6 +8018,7 @@ echo "PYTHON=$python" >> $config_host_mak
 echo "SPHINX_BUILD=$sphinx_build" >> $config_host_mak
 echo "SPHINX_WERROR=$sphinx_werror" >> $config_host_mak
 echo "GENISOIMAGE=$genisoimage" >> $config_host_mak
+echo "MESON=$meson" >> $config_host_mak
 echo "CC=$cc" >> $config_host_mak
 if $iasl -h > /dev/null 2>&1; then
   echo "IASL=$iasl" >> $config_host_mak
@@ -8611,6 +8629,30 @@ echo "# Automatically generated by configure - do not modify" > "$iotests_common
 echo >> "$iotests_common_env"
 echo "export PYTHON='$python'" >> "$iotests_common_env"
 
+if test "$skip_meson" = no; then
+rm -rf meson-private meson-info meson-logs
+NINJA=$PWD/ninjatool $meson setup \
+        --prefix "$prefix" \
+        --libdir "$libdir" \
+        --libexecdir "$libexecdir" \
+        --bindir "$bindir" \
+        --includedir "$includedir" \
+        --datadir "$datadir" \
+        --mandir "$mandir" \
+        --sysconfdir "$sysconfdir" \
+        --localstatedir "$local_statedir" \
+        -Doptimization=$(if test "$debug" = yes; then echo 0; else echo 2; fi) \
+        -Ddebug=$(if test "$debug_info" = yes; then echo true; else echo false; fi) \
+        -Dwerror=$(if test "$werror" = yes; then echo true; else echo false; fi) \
+        -Dstrip=$(if test "$strip_opt" = yes; then echo true; else echo false; fi) \
+        "$PWD" "$source_path"
+
+if test "$?" -ne 0 ; then
+    error_exit "meson setup failed"
+fi
+touch ninjatool.stamp
+fi
+
 # Save the configure command line for later reuse.
 cat <<EOD >config.status
 #!/bin/sh
@@ -8659,7 +8701,9 @@ preserve_env STRIP
 preserve_env WINDRES
 
 printf "exec" >>config.status
-printf " '%s'" "$0" "$@" >>config.status
+for i in "$0" "$@"; do
+  test "$i" = --skip-meson || printf " '%s'" "$i" >>config.status
+done
 echo ' "$@"' >>config.status
 chmod +x config.status
 

meson.build

@@ -0,0 +1,25 @@
+project('qemu', ['c'], meson_version: '>=0.55.0',
+        default_options: ['warning_level=1', 'c_std=gnu99', 'cpp_std=gnu++11', 'b_lundef=false'],
+        version: run_command('head', meson.source_root() / 'VERSION').stdout().strip())
+
+not_found = dependency('', required: false)
+keyval = import('unstable-keyval')
+config_host = keyval.load(meson.current_build_dir() / 'config-host.mak')
+
+add_project_arguments(config_host['QEMU_CFLAGS'].split(),
+                      native: false, language: ['c', 'objc'])
+add_project_arguments(config_host['QEMU_CXXFLAGS'].split(),
+                      native: false, language: 'cpp')
+add_project_link_arguments(config_host['QEMU_LDFLAGS'].split(),
+                           native: false, language: ['c', 'cpp', 'objc'])
+add_project_arguments(config_host['QEMU_INCLUDES'].split(),
+                      language: ['c', 'cpp', 'objc'])
+
+add_languages('cpp', required: false, native: false)
+if host_machine.system() == 'darwin'
+  add_languages('objc', required: false, native: false)
+endif
+
+configure_file(input: files('scripts/ninjatool.py'),
+               output: 'ninjatool',
+               configuration: config_host)