Re: [PATCH pahole] libbpf: build as PIC and statically link into libdwarves

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Mon, Feb 18, 2019 at 07:04:17PM -0800, Andrii Nakryiko escreveu:
> cc Yonghong (mistyped his email)

Applied, but before I split it into two patches, one bumping the minimum
required cmake version, with an explanation about why that is needed,
then the rest of the patch, with the explanation you provided.

Please try to make the patches in a granular fashion, with justification
for each independent part,

Thanks,

- Arnaldo
 
> On Mon, Feb 18, 2019 at 7:02 PM Andrii Nakryiko <andriin@fb.com> wrote:
> >
> > As libbpf is not yet widely available, it's safer to statically link it
> > into libdwarves for now. Easiest way to define that in cmake is through
> > OBJECT library with PIC.
> >
> > Signed-off-by: Andrii Nakryiko <andriin@fb.com>
> > ---
> >  CMakeLists.txt | 17 ++++++-----------
> >  1 file changed, 6 insertions(+), 11 deletions(-)
> >
> > diff --git a/CMakeLists.txt b/CMakeLists.txt
> > index d6929b4..e0fdaf7 100644
> > --- a/CMakeLists.txt
> > +++ b/CMakeLists.txt
> > @@ -1,5 +1,5 @@
> >  project(pahole C)
> > -cmake_minimum_required(VERSION 2.4.8)
> > +cmake_minimum_required(VERSION 2.8.8)
> >  cmake_policy(SET CMP0005 NEW)
> >
> >  INCLUDE_DIRECTORIES( ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR} )
> > @@ -72,24 +72,19 @@ if (NOT HAVE_REALLOCARRAY_SUPPORT)
> >  endif()
> >
> >  file(GLOB libbpf_sources "lib/bpf/src/*.c")
> > -add_library(bpf-static STATIC ${libbpf_sources})
> > -set_target_properties(bpf-static PROPERTIES OUTPUT_NAME bpf)
> > -target_include_directories(bpf-static PRIVATE
> > -                          ${CMAKE_CURRENT_SOURCE_DIR}/lib/bpf/include
> > -                          ${CMAKE_CURRENT_SOURCE_DIR}/lib/bpf/include/uapi)
> > -add_library(bpf-shared SHARED ${libbpf_sources})
> > -set_target_properties(bpf-shared PROPERTIES OUTPUT_NAME bpf)
> > -target_include_directories(bpf-shared PRIVATE
> > +add_library(bpf OBJECT ${libbpf_sources})
> > +set_property(TARGET bpf PROPERTY POSITION_INDEPENDENT_CODE 1)
> > +target_include_directories(bpf PRIVATE
> >                            ${CMAKE_CURRENT_SOURCE_DIR}/lib/bpf/include
> >                            ${CMAKE_CURRENT_SOURCE_DIR}/lib/bpf/include/uapi)
> >
> >  set(dwarves_LIB_SRCS dwarves.c dwarves_fprintf.c gobuffer strings
> >                      ctf_encoder.c ctf_loader.c libctf.c btf_encoder.c btf_loader.c libbtf.c
> >                      dwarf_loader.c dutil.c elf_symtab.c rbtree.c)
> > -add_library(dwarves SHARED ${dwarves_LIB_SRCS})
> > +add_library(dwarves SHARED ${dwarves_LIB_SRCS} $<TARGET_OBJECTS:bpf>)
> >  set_target_properties(dwarves PROPERTIES VERSION 1.0.0 SOVERSION 1)
> >  set_target_properties(dwarves PROPERTIES INTERFACE_LINK_LIBRARIES "")
> > -target_link_libraries(dwarves ${DWARF_LIBRARIES} ${ZLIB_LIBRARIES} bpf-shared)
> > +target_link_libraries(dwarves ${DWARF_LIBRARIES} ${ZLIB_LIBRARIES})
> >
> >  set(dwarves_emit_LIB_SRCS dwarves_emit.c)
> >  add_library(dwarves_emit SHARED ${dwarves_emit_LIB_SRCS})
> > --
> > 2.17.1
> >

-- 

- Arnaldo