On 2021-01-19, Tiezhu Yang wrote:
The current llvm/clang build procedure in samples/bpf/README.rst is out of date. See below that the links are not accessible any more. $ git clone http://llvm.org/git/llvm.git Cloning into 'llvm'... fatal: unable to access 'http://llvm.org/git/llvm.git/': Maximum (20) redirects followed $ git clone --depth 1 http://llvm.org/git/clang.git Cloning into 'clang'... fatal: unable to access 'http://llvm.org/git/clang.git/': Maximum (20) redirects followed The llvm community has adopted new ways to build the compiler. There are different ways to build llvm/clang, the Clang Getting Started page [1] has one way. As Yonghong said, it is better to just copy the build procedure in Documentation/bpf/bpf_devel_QA.rst to keep consistent. I verified the procedure and it is proved to be feasible, so we should update README.rst to reflect the reality. At the same time, update the related comment in Makefile. [1] https://clang.llvm.org/get_started.html Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx> Acked-by: Yonghong Song <yhs@xxxxxx> --- v2: Update the commit message suggested by Yonghong, thank you very much. samples/bpf/Makefile | 2 +- samples/bpf/README.rst | 17 ++++++++++------- 2 files changed, 11 insertions(+), 8 deletions(-) diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index 26fc96c..d061446 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -208,7 +208,7 @@ TPROGLDLIBS_xdpsock += -pthread -lcap TPROGLDLIBS_xsk_fwd += -pthread # Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline: -# make M=samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang +# make M=samples/bpf LLC=~/git/llvm-project/llvm/build/bin/llc CLANG=~/git/llvm-project/llvm/build/bin/clang LLC ?= llc CLANG ?= clang OPT ?= opt diff --git a/samples/bpf/README.rst b/samples/bpf/README.rst index dd34b2d..d1be438 100644 --- a/samples/bpf/README.rst +++ b/samples/bpf/README.rst @@ -65,17 +65,20 @@ To generate a smaller llc binary one can use:: Quick sniplet for manually compiling LLVM and clang (build dependencies are cmake and gcc-c++):: - $ git clone http://llvm.org/git/llvm.git - $ cd llvm/tools - $ git clone --depth 1 http://llvm.org/git/clang.git - $ cd ..; mkdir build; cd build - $ cmake .. -DLLVM_TARGETS_TO_BUILD="BPF;X86" - $ make -j $(getconf _NPROCESSORS_ONLN) + $ git clone https://github.com/llvm/llvm-project.git + $ mkdir -p llvm-project/llvm/build/install
llvm-project/llvm/build/install is not used.
+ $ cd llvm-project/llvm/build + $ cmake .. -G "Ninja" -DLLVM_TARGETS_TO_BUILD="BPF;X86" \ + -DLLVM_ENABLE_PROJECTS="clang" \ + -DBUILD_SHARED_LIBS=OFF \
-DBUILD_SHARED_LIBS=OFF is the default. It can be omitted.
+ -DCMAKE_BUILD_TYPE=Release \ + -DLLVM_BUILD_RUNTIME=OFF
-DLLVM_BUILD_RUNTIME=OFF can be omitted if none of compiler-rt/libc++/libc++abi is built.
+ $ ninja It is also possible to point make to the newly compiled 'llc' or 'clang' command via redefining LLC or CLANG on the make command line:: - make M=samples/bpf LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang + make M=samples/bpf LLC=~/git/llvm-project/llvm/build/bin/llc CLANG=~/git/llvm-project/llvm/build/bin/clang Cross compiling samples ----------------------- -- 2.1.0 -- You received this message because you are subscribed to the Google Groups "Clang Built Linux" group. To unsubscribe from this group and stop receiving emails from it, send an email to clang-built-linux+unsubscribe@xxxxxxxxxxxxxxxx. To view this discussion on the web visit https://groups.google.com/d/msgid/clang-built-linux/1611042978-21473-1-git-send-email-yangtiezhu%40loongson.cn.
