[dpdk-dev] [PATCH v8 01/12] config: change ABI versioning to global

[Anatoly Burakov]

From: Marcin Baran <marcinx.baran at intel.com>

As per new ABI policy [1], all of the libraries are now versioned using
one global ABI version. Stable libraries use the MAJOR.MINOR ABI
version for their shared objects, while experimental libraries
use the 0.MAJORMINOR convention for their versioning.
Experimental library versioning is managed globally. Changes in this
patch implement the necessary steps to enable that.

[1] https://doc.dpdk.org/guides/contributing/abi_policy.html

Signed-off-by: Marcin Baran <marcinx.baran at intel.com>
Signed-off-by: Pawel Modrak <pawelx.modrak at intel.com>
Signed-off-by: Anatoly Burakov <anatoly.burakov at intel.com>
Acked-by: Bruce Richardson <bruce.richardson at intel.com>
---

Notes:
    v6:
    - Silenced grep error message on trying to grep a directory
    
    v3:
    - Removed Windows support from Makefile changes
    - Removed unneeded path conversions from meson files
    
    v2:
    - Moved this to before ABI version bump to avoid compile breakage

 ABI_VERSION                                |  1 +
 buildtools/meson.build                     |  3 +++
 config/meson.build                         |  7 ++++++-
 doc/guides/contributing/abi_versioning.rst | 17 +++++++++--------
 doc/guides/contributing/coding_style.rst   |  8 +-------
 drivers/meson.build                        | 18 ++++++++++++------
 lib/meson.build                            | 17 +++++++++++------
 meson_options.txt                          |  2 --
 mk/rte.lib.mk                              | 14 +++++---------
 9 files changed, 48 insertions(+), 39 deletions(-)
 create mode 100644 ABI_VERSION

diff --git a/ABI_VERSION b/ABI_VERSION
new file mode 100644
index 0000000000..9a7c1e503f
--- /dev/null
+++ b/ABI_VERSION
@@ -0,0 +1 @@
+20.0
diff --git a/buildtools/meson.build b/buildtools/meson.build
index 8d0b9e0cd0..6ef2c5721c 100644
--- a/buildtools/meson.build
+++ b/buildtools/meson.build
@@ -14,3 +14,6 @@ if python3.found()
 else
 	map_to_def_cmd = ['meson', 'runpython', files('map_to_def.py')]
 endif
+
+# stable ABI always starts with "DPDK_"
+is_experimental_cmd = [find_program('grep', 'findstr'), '^DPDK_']
diff --git a/config/meson.build b/config/meson.build
index 2b1cb92e7e..3ffb73ab9c 100644
--- a/config/meson.build
+++ b/config/meson.build
@@ -18,6 +18,11 @@ endforeach
 # depending on the configuration options
 pver = meson.project_version().split('.')
 major_version = '@0 at .@1@'.format(pver.get(0), pver.get(1))
+abi_version = run_command(find_program('cat', 'more'),
+	files('../ABI_VERSION')).stdout().strip()
+# experimental libraries are versioned as 0.majorminor versions, e.g. 0.201
+ever = abi_version.split('.')
+experimental_abi_version = '0. at 0@@1@'.format(ever.get(0), ever.get(1))
 
 # extract all version information into the build configuration
 dpdk_conf.set('RTE_VER_YEAR', pver.get(0).to_int())
@@ -37,7 +42,7 @@ endif
 
 pmd_subdir_opt = get_option('drivers_install_subdir')
 if pmd_subdir_opt.contains('<VERSION>')
-	pmd_subdir_opt = major_version.join(pmd_subdir_opt.split('<VERSION>'))
+	pmd_subdir_opt = abi_version.join(pmd_subdir_opt.split('<VERSION>'))
 endif
 driver_install_path = join_paths(get_option('libdir'), pmd_subdir_opt)
 eal_pmd_path = join_paths(get_option('prefix'), driver_install_path)
diff --git a/doc/guides/contributing/abi_versioning.rst b/doc/guides/contributing/abi_versioning.rst
index 050c971dd8..a21f4e7a41 100644
--- a/doc/guides/contributing/abi_versioning.rst
+++ b/doc/guides/contributing/abi_versioning.rst
@@ -111,16 +111,17 @@ how this may be done.
  ...
 
 At the same time, the major ABI version is changed atomically across all
-libraries by incrementing the major version in individual library's soname, e.g.
-``libacl.so.21``. This is done by bumping the LIBABIVER number in the libraries
-Makefile to indicate to dynamic linking applications that this is a later, and
-possibly incompatible library version:
+libraries by incrementing the major version in the ABI_VERSION file. This is
+done globally for all libraries that declare a stable ABI. For libraries marked
+as EXPERIMENTAL, their major ABI version is always set to 0.
 
-.. code-block:: c
-
-   -LIBABIVER := 20
-   +LIBABIVER := 21
+Minor ABI versions
+~~~~~~~~~~~~~~~~~~
 
+Each non-LTS release will also increment minor ABI version, to permit multiple
+DPDK versions being installed alongside each other. Both stable and
+experimental ABI's are versioned using the global version file that is updated
+at the start of each release cycle, and are managed at the project level.
 
 Versioning Macros
 -----------------
diff --git a/doc/guides/contributing/coding_style.rst b/doc/guides/contributing/coding_style.rst
index a6843de5ad..841ef6d5c8 100644
--- a/doc/guides/contributing/coding_style.rst
+++ b/doc/guides/contributing/coding_style.rst
@@ -803,9 +803,8 @@ lpm, etc. For drivers, the same format of Makefile is used.
 	CFLAGS += -O3
 	CFLAGS += $(WERROR_FLAGS)
 
-	# the symbol version information for the library, and .so version
+	# the symbol version information for the library
 	EXPORT_MAP := rte_<name>_version.map
-	LIBABIVER := 1
 
 	# all source filenames are stored in SRCS-y
 	SRCS-$(CONFIG_RTE_LIBRTE_<NAME>) += rte_<name>.c
@@ -955,11 +954,6 @@ use_function_versioning
 	twice with suitable parameters for each of shared or static library
 	builds.
 
-version
-	**Default Value = 1**.
-	Specifies the ABI version of the library, and is used as the major
-	version number of the resulting ``.so`` library.
-
 Meson Build File Contents - Drivers
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
diff --git a/drivers/meson.build b/drivers/meson.build
index 823e3ef839..80cc7001fe 100644
--- a/drivers/meson.build
+++ b/drivers/meson.build
@@ -41,7 +41,6 @@ foreach class:dpdk_driver_classes
 		build = true # set to false to disable, e.g. missing deps
 		reason = '<unknown reason>' # set if build == false to explain
 		name = drv
-		version = 1
 		allow_experimental_apis = false
 		sources = []
 		objs = []
@@ -124,12 +123,19 @@ foreach class:dpdk_driver_classes
 					output: out_filename,
 					depends: [pmdinfogen, tmp_lib])
 
-			if get_option('per_library_versions')
-				lib_version = '@0 at .1'.format(version)
-				so_version = '@0@'.format(version)
+			version_map = '@0@/@1@/@2 at _version.map'.format(
+					meson.current_source_dir(),
+					drv_path, lib_name)
+
+			is_experimental = run_command(is_experimental_cmd,
+				files(version_map)).returncode()
+
+			if is_experimental != 0
+				lib_version = experimental_abi_version
+				so_version = experimental_abi_version
 			else
-				lib_version = major_version
-				so_version = major_version
+				lib_version = abi_version
+				so_version = abi_version
 			endif
 
 			# now build the static driver
diff --git a/lib/meson.build b/lib/meson.build
index bc8eb1d218..6ceb5e756e 100644
--- a/lib/meson.build
+++ b/lib/meson.build
@@ -47,7 +47,6 @@ foreach l:libraries
 	build = true
 	reason = '<unknown reason>' # set if build == false to explain why
 	name = l
-	version = 1
 	allow_experimental_apis = false
 	use_function_versioning = false
 	sources = []
@@ -106,12 +105,18 @@ foreach l:libraries
 				cflags += '-DRTE_USE_FUNCTION_VERSIONING'
 			endif
 
-			if get_option('per_library_versions')
-				lib_version = '@0 at .1'.format(version)
-				so_version = '@0@'.format(version)
+			version_map = '@0@/@1@/rte_ at 2@_version.map'.format(
+					meson.current_source_dir(), dir_name, name)
+
+			is_experimental = run_command(is_experimental_cmd,
+					files(version_map)).returncode()
+
+			if is_experimental != 0
+				lib_version = experimental_abi_version
+				so_version = experimental_abi_version
 			else
-				lib_version = major_version
-				so_version = major_version
+				lib_version = abi_version
+				so_version = abi_version
 			endif
 
 			# first build static lib
diff --git a/meson_options.txt b/meson_options.txt
index e6fcb884be..bc369d06c9 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -28,8 +28,6 @@ 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('per_library_versions', type: 'boolean', value: true,
-	description: 'true: each lib gets its own version number, false: DPDK version used for each lib')
 option('tests', type: 'boolean', value: true,
 	description: 'build unit tests')
 option('use_hpet', type: 'boolean', value: false,
diff --git a/mk/rte.lib.mk b/mk/rte.lib.mk
index 4df8849a08..3b318a5306 100644
--- a/mk/rte.lib.mk
+++ b/mk/rte.lib.mk
@@ -11,20 +11,16 @@ EXTLIB_BUILD ?= n
 # VPATH contains at least SRCDIR
 VPATH += $(SRCDIR)
 
-ifneq ($(CONFIG_RTE_MAJOR_ABI),)
-ifneq ($(LIBABIVER),)
-LIBABIVER := $(CONFIG_RTE_MAJOR_ABI)
-endif
+ifneq ($(shell grep -s "^DPDK_" $(SRCDIR)/$(EXPORT_MAP)),)
+LIBABIVER := $(shell cat $(RTE_SRCDIR)/ABI_VERSION)
+else
+# EXPERIMENTAL ABI is versioned as 0.major+minor, e.g. 0.201 for 20.1 ABI
+LIBABIVER := 0.$(shell cat $(RTE_SRCDIR)/ABI_VERSION | td -d '.')
 endif
 
 ifeq ($(CONFIG_RTE_BUILD_SHARED_LIB),y)
 LIB := $(patsubst %.a,%.so.$(LIBABIVER),$(LIB))
 ifeq ($(EXTLIB_BUILD),n)
-ifeq ($(CONFIG_RTE_MAJOR_ABI),)
-ifeq ($(CONFIG_RTE_NEXT_ABI),y)
-LIB := $(LIB).1
-endif
-endif
 CPU_LDFLAGS += --version-script=$(SRCDIR)/$(EXPORT_MAP)
 endif
 endif
-- 
2.17.1