build: alias default build as generic

The current machine='default' build name is not descriptive. The actual
default build is machine='native'. Add an alternative string which does
the same build and better describes what we're building:
machine='generic'. Leave machine='default' for backwards compatibility.

Signed-off-by: Juraj Linkeš <juraj.linkes@pantheon.tech>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>

.ci/linux-build.sh

@@ -77,7 +77,7 @@ else
     OPTS="$OPTS -Dexamples=all"
 fi
 
-OPTS="$OPTS -Dmachine=default"
+OPTS="$OPTS -Dmachine=generic"
 OPTS="$OPTS --default-library=$DEF_LIB"
 OPTS="$OPTS --buildtype=debugoptimized"
 OPTS="$OPTS -Dcheck_includes=true"

config/arm/meson.build

@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: BSD-3-Clause
 # Copyright(c) 2017 Intel Corporation.
 # Copyright(c) 2017 Cavium, Inc
+# Copyright(c) 2021 PANTHEON.tech s.r.o.
 
 # common flags to all aarch64 builds, with lowest priority
 flags_common = [
@@ -208,8 +209,8 @@ if dpdk_conf.get('RTE_ARCH_32')
 else
 	# aarch64 build
 	if not meson.is_cross_build()
-		if machine == 'default'
-			# default build
+		if machine == 'generic'
+			# generic build
 			implementer_id = 'generic'
 			part_number = 'generic'
 		else
@@ -256,7 +257,7 @@ else
 		      '(-Dmachine=generic) build.')
 	endif
 
-	# use default flags with implementer flags
+	# use common flags with implementer flags
 	dpdk_flags = flags_common + implementer_config['flags'] + part_number_config.get('flags', [])
 
 	# apply supported machine args

config/meson.build

@@ -70,21 +70,22 @@ else
 	machine = get_option('machine')
 endif
 
-# machine type 'default' is special, it defaults to the per arch agreed common
-# minimal baseline needed for DPDK.
+# machine type 'generic' is special, it selects the per arch agreed common
+# minimal baseline needed for DPDK. Machine type 'default' is also supported
+# with the same meaning for backwards compatibility.
 # That might not be the most optimized, but the most portable version while
 # still being able to support the CPU features required for DPDK.
 # This can be bumped up by the DPDK project, but it can never be an
 # invariant like 'native'
-if machine == 'default'
+if machine == 'default' or machine == 'generic'
 	if host_machine.cpu_family().startswith('x86')
-		# matches the old pre-meson build systems default
+		# matches the old pre-meson build systems generic machine
 		machine = 'corei7'
 	elif host_machine.cpu_family().startswith('arm')
 		machine = 'armv7-a'
 	elif host_machine.cpu_family().startswith('aarch')
-		# arm64 manages defaults in config/arm/meson.build
-		machine = 'default'
+		# arm64 manages generic config in config/arm/meson.build
+		machine = 'generic'
 	elif host_machine.cpu_family().startswith('ppc')
 		machine = 'power8'
 	endif

devtools/test-meson-builds.sh

@@ -223,12 +223,12 @@ done
 # test compilation with minimal x86 instruction set
 # Set the install path for libraries to "lib" explicitly to prevent problems
 # with pkg-config prefixes if installed in "lib/x86_64-linux-gnu" later.
-default_machine='nehalem'
-if ! check_cc_flags "-march=$default_machine" ; then
-	default_machine='corei7'
+generic_machine='nehalem'
+if ! check_cc_flags "-march=$generic_machine" ; then
+	generic_machine='corei7'
 fi
-build build-x86-default cc skipABI -Dcheck_includes=true \
-	-Dlibdir=lib -Dmachine=$default_machine $use_shared
+build build-x86-generic cc skipABI -Dcheck_includes=true \
+	-Dlibdir=lib -Dmachine=$generic_machine $use_shared
 
 # 32-bit with default compiler
 if check_cc_flags '-m32' ; then
@@ -271,10 +271,10 @@ for f in $srcdir/config/ppc/ppc* ; do
 	build $targetdir $f ABI $use_shared
 done
 
-# Test installation of the x86-default target, to be used for checking
+# Test installation of the x86-generic target, to be used for checking
 # the sample apps build using the pkg-config file for cflags and libs
 load_env cc
-build_path=$(readlink -f $builds_dir/build-x86-default)
+build_path=$(readlink -f $builds_dir/build-x86-generic)
 export DESTDIR=$build_path/install
 install_target $build_path $DESTDIR
 pc_file=$(find $DESTDIR -name libdpdk.pc)

doc/guides/prog_guide/build-sdk-meson.rst

@@ -85,7 +85,7 @@ Project-specific options are passed used -Doption=value::
 
 	meson -Denable_docs=true fullbuild  # build and install docs
 
-	meson -Dmachine=default  # use builder-independent baseline -march
+	meson -Dmachine=generic  # use builder-independent baseline -march
 
 	meson -Ddisable_drivers=event/*,net/tap  # disable tap driver and all
 					# eventdev PMDs for a smaller build
@@ -114,7 +114,7 @@ Examples of setting some of the same options using meson configure::
         re-scan from meson.
 
 .. note::
-        machine=default uses a config that works on all supported architectures
+        machine=generic uses a config that works on all supported architectures
         regardless of the capabilities of the machine where the build is happening.
 
 As well as those settings taken from ``meson configure``, other options

meson_options.txt

@@ -25,7 +25,7 @@ option('include_subdir_arch', type: 'string', value: '',
 option('kernel_dir', type: 'string', value: '',
 	description: 'Path to the kernel for building kernel modules. Headers must be in $kernel_dir or $kernel_dir/build. Modules will be installed in /lib/modules.')
 option('machine', type: 'string', value: 'native',
-	description: 'set the target machine type')
+	description: 'set the target machine type or "generic", a build usable on all machines of the build machine architecture or "native", which lets the compiler pick the architecture of the build machine.')
 option('max_ethports', type: 'integer', value: 32,
 	description: 'maximum number of Ethernet devices')
 option('max_lcores', type: 'integer', value: 128,