[PATCH 22/23] perf tools: Fix -ldw/-lelf link test when static linking

[Arnaldo Carvalho de Melo]

From: Mike Frysinger <vapier@xxxxxxxxxxxx>

Since libelf sometimes uses libpthread, we have to list that after -lelf
when someone tries to build statically.  Else things go boom:

Makefile:479: *** No libelf.h/libelf found, please install \
	libelf-dev/elfutils-libelf-devel.  Stop.

Similarly, the -ldw test fails as it often uses -lz:

Makefile:462: No libdw.h found or old libdw.h found or elfutils is older \
	than 0.138, disables dwarf support. Please install new elfutils-devel/libdw-dev

And if we add debugging to try-cc, we see:
+ echo '#include <dwarf.h>

int main(void)
{
        Dwarf *dbg = dwarf_begin(0, DWARF_C_READ);
        return (long)dbg;
}'
+ i686-pc-linux-gnu-gcc -x c - -O2 -pipe -march=atom -mtune=atom -mfpmath=sse -g \
	-D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE \
	-ldw -lelf -static -lpthread -lrt -lelf -lm -o .24368
/usr/lib/libdw.a(dwarf_begin_elf.o):function check_section.isra.1: error: undefined reference to 'inflateInit_'
/usr/lib/libdw.a(dwarf_begin_elf.o):function check_section.isra.1: error: undefined reference to 'inflate'
/usr/lib/libdw.a(dwarf_begin_elf.o):function check_section.isra.1: error: undefined reference to 'inflateReset'
/usr/lib/libdw.a(dwarf_begin_elf.o):function check_section.isra.1: error: undefined reference to 'inflateEnd'

+ echo '#include <libelf.h>

int main(void)
{
        Elf *elf = elf_begin(0, ELF_C_READ, 0);
        return (long)elf;
}'
+ i686-pc-linux-gnu-gcc -x c - -O2 -pipe -march=atom -mtune=atom -mfpmath=sse -g \
	-D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE \
	-static -lpthread -lrt -lelf -lm -o .19216
/usr/lib/libelf.a(elf_begin.o):function file_read_elf: error: undefined reference to 'pthread_rwlock_init'
/usr/lib/libelf.a(elf_begin.o):function __libelf_read_mmaped_file: error: undefined reference to 'pthread_rwlock_init'
/usr/lib/libelf.a(elf_begin.o):function __libelf_read_mmaped_file: error: undefined reference to 'pthread_rwlock_init'
/usr/lib/libelf.a(elf_begin.o):function read_file: error: undefined reference to 'pthread_rwlock_init'
/usr/lib/libelf.a(elf_begin.o):function lock_dup_elf.8072: error: undefined reference to 'pthread_rwlock_unlock'
/usr/lib/libelf.a(elf_begin.o):function lock_dup_elf.8072: error: undefined reference to 'pthread_rwlock_wrlock'
/usr/lib/libelf.a(elf_begin.o):function elf_begin: error: undefined reference to 'pthread_rwlock_rdlock'
/usr/lib/libelf.a(elf_begin.o):function elf_begin: error: undefined reference to 'pthread_rwlock_unlock'

Signed-off-by: Mike Frysinger <vapier@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Link: http://lkml.kernel.org/r/1368073064-18276-1-git-send-email-vapier@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/lib/lk/Makefile      | 2 +-
 tools/perf/config/Makefile | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/lib/lk/Makefile b/tools/lib/lk/Makefile
index f0ecc0a..280dd82 100644
--- a/tools/lib/lk/Makefile
+++ b/tools/lib/lk/Makefile
@@ -29,7 +29,7 @@ LIB_OBJS += $(OUTPUT)debugfs.o
 LIBFILE = liblk.a
 
 CFLAGS = -ggdb3 -Wall -Wextra -std=gnu99 -Werror -O6 -D_FORTIFY_SOURCE=2 $(EXTRA_WARNINGS) $(EXTRA_CFLAGS) -fPIC
-EXTLIBS = -lpthread -lrt -lelf -lm
+EXTLIBS = -lelf -lpthread -lrt -lm
 ALL_CFLAGS = $(CFLAGS) $(BASIC_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64
 ALL_LDFLAGS = $(LDFLAGS)
 
diff --git a/tools/perf/config/Makefile b/tools/perf/config/Makefile
index f446895..b5d9238 100644
--- a/tools/perf/config/Makefile
+++ b/tools/perf/config/Makefile
@@ -85,7 +85,7 @@ CFLAGS += -Wall
 CFLAGS += -Wextra
 CFLAGS += -std=gnu99
 
-EXTLIBS = -lpthread -lrt -lelf -lm
+EXTLIBS = -lelf -lpthread -lrt -lm
 
 ifeq ($(call try-cc,$(SOURCE_HELLO),$(CFLAGS) -Werror -fstack-protector-all,-fstack-protector-all),y)
   CFLAGS += -fstack-protector-all
@@ -165,7 +165,7 @@ else
     LIBDW_LDFLAGS := -L$(LIBDW_DIR)/lib
   endif
 
-  FLAGS_DWARF=$(CFLAGS) $(LIBDW_CFLAGS) -ldw -lelf $(LIBDW_LDFLAGS) $(LDFLAGS) $(EXTLIBS)
+  FLAGS_DWARF=$(CFLAGS) $(LIBDW_CFLAGS) -ldw -lz -lelf $(LIBDW_LDFLAGS) $(LDFLAGS) $(EXTLIBS)
   ifneq ($(call try-cc,$(SOURCE_DWARF),$(FLAGS_DWARF),libdw),y)
     msg := $(warning No libdw.h found or old libdw.h found or elfutils is older than 0.138, disables dwarf support. Please install new elfutils-devel/libdw-dev);
     NO_DWARF := 1
-- 
1.8.1.4

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