[dpdk-dev] [PATCH] mk: fix lib filtering

Olivier Matz olivier.matz at 6wind.com
Thu Apr 6 16:14:55 CEST 2017


I get the following error when linking the test application:
  build/lib/librte_pmd_thunderx_nicvf.a(nicvf_hw.o):
  In function `nicvf_qsize_regbit':
  drivers/net/thunderx/base/nicvf_hw.c:451: undefined reference to `log2'
  build/lib/librte_pmd_thunderx_nicvf.a(nicvf_hw.o):
  In function `nicvf_rss_reta_update':
  drivers/net/thunderx/base/nicvf_hw.c:804: undefined reference to `log2'
  build/lib/librte_pmd_thunderx_nicvf.a(nicvf_hw.o):
  In function `nicvf_rss_reta_query':
  drivers/net/thunderx/base/nicvf_hw.c:825: undefined reference to `log2'

While I don't know why it does not happen for a default build, the error
can be explained. The link command line is:

   gcc -o test ... *.o ... -Wl,-lm ... -Wl,-lrte_pmd_thunderx_nicvf ...

rte_pmd_thunderx_nicvf needs the math library, and it should be
added after. This is not the case because the test application also
adds the math library.

The makefile already filters the libraries, but it keeps the first
occurrence of the lib. Instead, the last one should be kept.

Fixes: edf4d331dcdb ("mk: eliminate duplicates from libraries list")

Cc: stable at dpdk.org
Signed-off-by: Olivier Matz <olivier.matz at 6wind.com>
---
 mk/rte.app.mk | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/mk/rte.app.mk b/mk/rte.app.mk
index fcc3a5795..4c659e971 100644
--- a/mk/rte.app.mk
+++ b/mk/rte.app.mk
@@ -186,10 +186,21 @@ _LDLIBS-y += $(EXECENV_LDLIBS)
 
 LDLIBS += $(_LDLIBS-y) $(CPU_LDLIBS) $(EXTRA_LDLIBS)
 
-# Eliminate duplicates without sorting
-LDLIBS := $(shell echo $(LDLIBS) | \
-	awk '{for (i = 1; i <= NF; i++) { \
-		if ($$i !~ /^-l.*/ || !seen[$$i]++) print $$i }}')
+# all the words except the first one
+allbutfirst = $(wordlist 2,$(words $(1)),$(1))
+
+# Eliminate duplicates without sorting, only keep the last occurrence
+filter-libs = \
+	$(if $(1),$(strip\
+		$(if \
+			$(and \
+				$(filter $(firstword $(1)),$(call allbutfirst,$(1))),\
+				$(filter -l%,$(firstword $(1)))),\
+			,\
+			$(firstword $(1))) \
+		$(call filter-libs,$(call allbutfirst,$(1)))))
+
+LDLIBS := $(call filter-libs,$(LDLIBS))
 
 ifeq ($(RTE_DEVEL_BUILD)$(CONFIG_RTE_BUILD_SHARED_LIB),yy)
 LDFLAGS += -rpath=$(RTE_SDK_BIN)/lib
-- 
2.11.0



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