[dpdk-stable] patch 'mk: fix lib filtering when linking app' has been queued to stable release 17.02.1

[Yuanhan Liu]

Hi,

FYI, your patch has been queued to stable release 17.02.1

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 05/28/17. So please
shout if anyone has objections.

Thanks.

	--yliu

---
>From 26f1be3d2aff2b3a9b075708c3950844bfff6428 Mon Sep 17 00:00:00 2001
From: Olivier Matz <olivier.matz at 6wind.com>
Date: Thu, 6 Apr 2017 16:14:55 +0200
Subject: [PATCH] mk: fix lib filtering when linking app

[ upstream commit ab338eb44ebb79840dab1de2742c07070ae3bf0e ]

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")

Signed-off-by: Olivier Matz <olivier.matz at 6wind.com>
Acked-by: Thomas Monjalon <thomas.monjalon 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 92f3635..dde1079 100644
--- a/mk/rte.app.mk
+++ b/mk/rte.app.mk
@@ -172,10 +172,21 @@ _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
-- 
1.9.0