CHROMIUM: perf tools: fix -ldw/-lelf link test when static linking

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'

BUG=None
TEST=`LDFLAGS=-static emerge-x86-alex perf` works

Change-Id: Idfa38ae36d22bcc669199bbd8e74f83eb97ddda9
Signed-off-by: Mike Frysinger <vapier@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/50498
Reviewed-by: Olof Johansson <olofj@chromium.org>

diff --git a/tools/perf/Makefile b/tools/perf/Makefile
index 92271d3..6e989ba 100644 (file)
--- a/tools/perf/Makefile
+++ b/tools/perf/Makefile
@@ -117,7 +117,7 @@ ifndef PERF_DEBUG
 endif
 
 CFLAGS = -fno-omit-frame-pointer -ggdb3 -Wall -Wextra -std=gnu99 $(CFLAGS_WERROR) $(CFLAGS_OPTIMIZE) -D_FORTIFY_SOURCE=2 $(EXTRA_WARNINGS) $(EXTRA_CFLAGS)
-EXTLIBS = -lpthread -lrt -lelf -lm
+EXTLIBS = -lelf -lpthread -lrt -lm
 ALL_CFLAGS = $(CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE
 ALL_LDFLAGS = $(LDFLAGS)
 STRIP ?= strip
@@ -457,7 +457,7 @@ PYRF_OBJS += $(OUTPUT)util/xyarray.o
 -include config.mak
 
 ifndef NO_DWARF
-FLAGS_DWARF=$(ALL_CFLAGS) -ldw -lelf $(ALL_LDFLAGS) $(EXTLIBS)
+FLAGS_DWARF=$(ALL_CFLAGS) -ldw -lz -lelf $(ALL_LDFLAGS) $(EXTLIBS)
 ifneq ($(call try-cc,$(SOURCE_DWARF),$(FLAGS_DWARF)),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