[dpdk-dev] [PATCH v2] app: fix plugin load on static builds

[Olivier Matz <olivier.matz@6wind.com>]

When dpdk is compiled as static libraries, it is not possible
to load a plugin from an application. We get the following error:

  EAL: librte_pmd_xxxx.so: undefined symbol: per_lcore__rte_errno

This happens because the dpdk symbols are not exported. Add them to the
dynamic symbol table by using '-Wl,--export-dynamic'. This option was
previously present when compiled with Makefiles, it was introduced in
commit f9a08f650211 ("eal: add support for shared object drivers")

Also add it to the pkg-config file.

Fixes: 16ade738fd0d ("app/testpmd: build with meson")
Fixes: 89f0711f9ddf ("examples: build some samples with meson")
Cc: stable@dpdk.org

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
---
 app/meson.build      | 6 ++++++
 examples/meson.build | 7 ++++++-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/app/meson.build b/app/meson.build
index eb74f215a3..fd72d7da68 100644
--- a/app/meson.build
+++ b/app/meson.build
@@ -25,6 +25,10 @@ apps = [
 lib_execinfo = cc.find_library('execinfo', required: false)
 
 default_cflags = machine_args + ['-DALLOW_EXPERIMENTAL_API']
+default_ldflags = []
+if get_option('default_library') == 'static'
+	default_ldflags += ['-Wl,--export-dynamic']
+endif
 
 foreach app:apps
 	build = true
@@ -32,6 +36,7 @@ foreach app:apps
 	sources = []
 	includes = []
 	cflags = default_cflags
+	ldflags = default_ldflags
 	objs = [] # other object files to link against, used e.g. for
 	          # instruction-set optimized versions of code
 
@@ -58,6 +63,7 @@ foreach app:apps
 		executable('dpdk-' + name,
 				sources,
 				c_args: cflags,
+				link_args: ldflags,
 				link_whole: link_libs,
 				dependencies: dep_objs,
 				install_rpath: join_paths(get_option('prefix'),
diff --git a/examples/meson.build b/examples/meson.build
index 46ec80919e..f643ec1bad 100644
--- a/examples/meson.build
+++ b/examples/meson.build
@@ -63,6 +63,10 @@ default_cflags = machine_args
 if cc.has_argument('-Wno-format-truncation')
 	default_cflags += '-Wno-format-truncation'
 endif
+default_ldflags = dpdk_extra_ldflags
+if get_option('default_library') == 'static'
+	default_ldflags += ['-Wl,--export-dynamic']
+endif
 
 foreach example: examples
 	name = example.split('/')[-1]
@@ -70,6 +74,7 @@ foreach example: examples
 	sources = []
 	allow_experimental_apis = false
 	cflags = default_cflags
+	ldflags = default_ldflags
 
 	ext_deps = [execinfo]
 	includes = [include_directories(example)]
@@ -91,7 +96,7 @@ foreach example: examples
 		executable('dpdk-' + name, sources,
 			include_directories: includes,
 			link_whole: link_whole_libs,
-			link_args: dpdk_extra_ldflags,
+			link_args: ldflags,
 			c_args: cflags,
 			dependencies: dep_objs)
 	elif not allow_skips
-- 
2.25.1