[dpdk-dev] [PATCH] mk: fix parallel build of test resources

[Thomas Monjalon <thomas.monjalon@6wind.com>]

The build was failing sometimes when building with multiple
parallel jobs:
    # rm build/build/app/test/*res*
    # make -j6
    objcopy: 'resource.tmp': No such file

The reason is that each resource was built from the same temporary file.
The failure is seen because of a race condition when removing the
temporary file after each resource creation.
It also means that some resources may be created from the wrong source.

The fix is to have a different temporary file for each resource.
We do not use the original source file because it has a long path
which is used by objcopy to name the symbols after some transformations.
The trick is to create a symbolic link of the source file if it is not
already in the current build directory. Then we just have to replace
the dot by an underscore to predict the symbol names to redefine.

Fixes: 1e9e0a6270 ("app/test: fix resource creation with objcopy on FreeBSD")

Signed-off-by: Thomas Monjalon <thomas.monjalon@6wind.com>
---
 app/test/Makefile | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/app/test/Makefile b/app/test/Makefile
index 9fa03fb..46f6005 100644
--- a/app/test/Makefile
+++ b/app/test/Makefile
@@ -43,14 +43,14 @@ define linked_resource
 SRCS-y += $(1).res.o
 $(1).res.o: $(2)
 	@  echo '  MKRES $$@'
-	$Q ln -fs $$< resource.tmp
+	$Q [ "$$(<D)" = . ] || ln -fs $$<
 	$Q $(OBJCOPY) -I binary -B $(RTE_OBJCOPY_ARCH) -O $(RTE_OBJCOPY_TARGET) \
 		--rename-section                                         \
 			.data=.rodata,alloc,load,data,contents,readonly  \
-		--redefine-sym _binary_resource_tmp_start=beg_$(1)       \
-		--redefine-sym _binary_resource_tmp_end=end_$(1)         \
-		--redefine-sym _binary_resource_tmp_size=siz_$(1)        \
-		resource.tmp $$@ && rm -f resource.tmp
+		--redefine-sym _binary_$$(subst .,_,$$(<F))_start=beg_$(1) \
+		--redefine-sym _binary_$$(subst .,_,$$(<F))_end=end_$(1)   \
+		--redefine-sym _binary_$$(subst .,_,$$(<F))_size=siz_$(1)  \
+		$$(<F) $$@
 endef
 
 ifeq ($(CONFIG_RTE_APP_TEST_RESOURCE_TAR),y)
-- 
2.7.0