[dpdk-dev] [RFC PATCH v1] build: add platform meson option

["Juraj Linkeš" <juraj.linkes@pantheon.tech>]

The current meson option 'machine' should only specify the ISA, which is
not sufficient for Arm, where setting ISA implies other setting as well.
Add a new meson option, 'platform', which differentiates the type of the
build (native/generic) and sets machine accordingly, unless the user
chooses to override it.

Signed-off-by: Juraj Linkeš <juraj.linkes@pantheon.tech>
---
 config/arm/meson.build |  2 +-
 config/meson.build     | 14 +++++++++++++-
 meson_options.txt      |  6 ++++--
 3 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/config/arm/meson.build b/config/arm/meson.build
index 42b4e43c7..ac680956f 100644
--- a/config/arm/meson.build
+++ b/config/arm/meson.build
@@ -6,7 +6,7 @@
 march_opt = '-march=@0@'.format(machine)
 
 arm_force_native_march = false
-arm_force_default_march = (machine == 'default')
+arm_force_default_march = (platform == 'generic')
 
 flags_common_default = [
 	# Accelarate rte_memcpy. Be sure to run unit test (memcpy_perf_autotest)
diff --git a/config/meson.build b/config/meson.build
index c02802c18..41d32e63e 100644
--- a/config/meson.build
+++ b/config/meson.build
@@ -63,6 +63,8 @@ if not is_windows
 			pmd_subdir_opt)
 endif
 
+platform = get_option('platform')
+
 # set the machine type and cflags for it
 if meson.is_cross_build()
 	machine = host_machine.cpu()
@@ -70,13 +72,23 @@ else
 	machine = get_option('machine')
 endif
 
+if platform == 'native'
+	if machine == 'auto'
+		machine = 'native'
+	endif
+elif platform == 'generic'
+	if machine == 'auto'
+		machine = 'default'
+	endif
+endif
+
+if machine == 'default'
 # machine type 'default' is special, it defaults to the per arch agreed common
 # minimal baseline needed for DPDK.
 # 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 host_machine.cpu_family().startswith('x86')
 		# matches the old pre-meson build systems default
 		machine = 'corei7'
diff --git a/meson_options.txt b/meson_options.txt
index e384e6dbb..1a5e47fd3 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -20,14 +20,16 @@ option('kernel_dir', type: 'string', value: '',
 	description: 'Path to the kernel for building kernel modules. Headers must be in $kernel_dir/build. Modules will be installed in $DEST_DIR/$kernel_dir/extra/dpdk.')
 option('lib_musdk_dir', type: 'string', value: '',
 	description: 'path to the MUSDK library installation directory')
-option('machine', type: 'string', value: 'native',
-	description: 'set the target machine type')
+option('machine', type: 'string', value: 'auto',
+	description: 'set the target machine type/ISA')
 option('max_ethports', type: 'integer', value: 32,
 	description: 'maximum number of Ethernet devices')
 option('max_lcores', type: 'integer', value: 128,
 	description: 'maximum number of cores/threads supported by EAL')
 option('max_numa_nodes', type: 'integer', value: 4,
 	description: 'maximum number of NUMA nodes supported by EAL')
+option('platform', type: 'string', value: 'generic',
+	description: 'Platform to build for, either "native" or "generic".')
 option('enable_trace_fp', type: 'boolean', value: false,
 	description: 'enable fast path trace points.')
 option('tests', type: 'boolean', value: true,
-- 
2.20.1