[PATCH RESEND v3 2/3] perf: build: Fix build feature-dwarf_getlocations fail for old libdw

Yang Jihong
2024-09-19T01:35:47Z

For libdw versions below 0.177, need to link libdl.a in addition to
libbebl.a during static compilation, otherwise feature-dwarf_getlocations
compilation will fail.

Before:

$ make LDFLAGS=-static
BUILD: Doing 'make -j20' parallel build
<SNIP>
Makefile.config:483: Old libdw.h, finding variables at given 'perf probe' point will not work, install elfutils-devel/libdw-dev >= 0.157
<SNIP>

$ cat ../build/feature/test-dwarf_getlocations.make.output
/usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/9/../../../x86_64-linux-gnu/libebl.a(eblclosebackend.o): in function `ebl_closebackend':
(.text+0x20): undefined reference to `dlclose'
collect2: error: ld returned 1 exit status

After:

$ make LDFLAGS=-static
<SNIP>
Auto-detecting system features:
... dwarf: [ on ]
<SNIP>

$ ./perf probe
Usage: perf probe [<options>] 'PROBEDEF' ['PROBEDEF' ...]
or: perf probe [<options>] --add 'PROBEDEF' [--add 'PROBEDEF' ...]
or: perf probe [<options>] --del '[GROUP:]EVENT' ...
or: perf probe --list [GROUP:]EVENT ...
<SNIP>

Fixes: 536661da6ea1 ("perf: build: Only link libebl.a for old libdw")
Reviewed-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Yang Jihong <yangjihong@bytedance.com>
---
tools/build/feature/Makefile | 3 +++
tools/perf/Makefile.config | 5 ++++-
2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
index 6f1c961f0ede..1658596188bf 100644
--- a/tools/build/feature/Makefile
+++ b/tools/build/feature/Makefile
@@ -181,6 +181,9 @@ ifeq ($(findstring -static,${LDFLAGS}),-static)
ifeq ($(shell test $(LIBDW_VERSION_2) -lt 177; echo $$?),0)
DWARFLIBS += -lebl
endif
+
+ # Must put -ldl after -lebl for dependency
+ DWARFLIBS += -ldl
endif

$(OUTPUT)test-dwarf.bin:
diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index 0049fd41cf57..4ddb27a48eed 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -147,7 +147,7 @@ ifdef LIBDW_DIR
endif
DWARFLIBS := -ldw
ifeq ($(findstring -static,${LDFLAGS}),-static)
- DWARFLIBS += -lelf -ldl -lz -llzma -lbz2 -lzstd
+ DWARFLIBS += -lelf -lz -llzma -lbz2 -lzstd

LIBDW_VERSION := $(shell $(PKG_CONFIG) --modversion libdw).0.0
LIBDW_VERSION_1 := $(word 1, $(subst ., ,$(LIBDW_VERSION)))
@@ -158,6 +158,9 @@ ifeq ($(findstring -static,${LDFLAGS}),-static)
ifeq ($(shell test $(LIBDW_VERSION_2) -lt 177; echo $$?),0)
DWARFLIBS += -lebl
endif
+
+ # Must put -ldl after -lebl for dependency
+ DWARFLIBS += -ldl
endif
FEATURE_CHECK_CFLAGS-libdw-dwarf-unwind := $(LIBDW_CFLAGS)
FEATURE_CHECK_LDFLAGS-libdw-dwarf-unwind := $(LIBDW_LDFLAGS) $(DWARFLIBS)
--
2.25.1