Statical linking result a very large perf executable. This patch makes
perf link clang libraries dynamically by using '-lclangBasic' style
linking option. If dynamic clang libraries are detected, gcc will use
them by default.
Test result:
(Build clang/llvm dynamically by setting -DBUILD_SHARED_LIBS=ON
in its cmake configuration.)
$ size ~/perf
text data bss dec hex filename
4223234 754544 23956048 28933826 1b97ec2 /home/wn/perf
$ strip ~/perf
$ ls -sh ~/perf
4.8M /home/wn/perf
Compare with statical linking:
$ ls -sh ~/perf
969M /home/wn/perf
$ strip ~/perf
$ ls -sh ~/perf
52M /home/wn/perf
Signed-off-by: Wang Nan <wangn...@huawei.com>
Cc: Arnaldo Carvalho de Melo <a...@redhat.com>
Cc: Alexei Starovoitov <a...@fb.com>
Cc: He Kuang <heku...@huawei.com>
Cc: Jiri Olsa <jo...@kernel.org>
Cc: Zefan Li <lize...@huawei.com>
Cc: pi3or...@163.com
---
tools/perf/Makefile.perf | 20 ++++++++++++++++++--
1 file changed, 18 insertions(+), 2 deletions(-)
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 10495c9..192f2d6 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -329,9 +329,25 @@ endif
LIBS = -Wl,--whole-archive $(PERFLIBS) -Wl,--no-whole-archive
-Wl,--start-group $(EXTLIBS) -Wl,--end-group
ifeq ($(USE_CLANG), 1)
+ # Only partial of the required clang libraries are listed.
+ #
+ # In case of dynamical linking, if clang is built and installed
+ # correctly, ld can infer the full list automatically. However,
+ # I observed a potential bug in 3.9.0 that four libraries
+ # (ASTMatchers, Format Rewrite and ToolingCore) are lost.
+ #
+ # In case of statical linking, providing the full list causes
+ # linking time dramatically increases because of --{start,end}-group.
+ #
+ # If linking error, replace CLANGLIBS_LIST with the full list
+ # and try again.
+ #
+ # The full list should be:
+ #
+ # Basic CodeGen Frontend Tooling AST Lex Driver Edit Parse Sema
+ # Serialization ASTMatchers Format Rewrite ToolingCore Analysis
CLANGLIBS_LIST = AST Basic CodeGen Driver Frontend Lex Tooling Edit Sema
Analysis Parse Serialization
- LIBCLANG = $(foreach l,$(CLANGLIBS_LIST),$(wildcard $(shell $(LLVM_CONFIG)
--libdir)/libclang$(l).a))
- LIBS += -Wl,--start-group $(LIBCLANG) -Wl,--end-group
+ LIBS += -L$(shell $(LLVM_CONFIG) --libdir) -Wl,--start-group $(foreach
l,$(CLANGLIBS_LIST),-lclang$(l)) -Wl,--end-group
endif
ifeq ($(USE_LLVM), 1)
--
2.10.1
