Em Thu, Jun 06, 2019 at 10:35:32PM +0800, Leo Yan escreveu: > On Thu, Jun 06, 2019 at 11:08:00AM -0300, Arnaldo Carvalho de Melo wrote: > > Em Thu, Jun 06, 2019 at 05:48:45PM +0800, Leo Yan escreveu: > > > To build this program successfully with clang, there have three > > > compiler options need to be specified: > > > > > > - Header file path: tools/perf/include/bpf; > > > - Specify architecture; > > > - Define macro __NR_CPUS__. > > > > So, this shouldn't be needed, all of this is supposed to be done > > automagically, have you done a 'make -C tools/perf install'? > > I missed the up operation. But after git pulled the lastest code base > from perf/core branch and used the command 'make -C tools/perf > install', I still saw the eBPF build failure. > > Just now this issue is fixed after I removed the config > 'clang-bpf-cmd-template' from ~/.perfconfig; the reason is I followed > up the Documentation/perf-config.txt to set the config as below: > > clang-bpf-cmd-template = "$CLANG_EXEC -D__KERNEL__ $CLANG_OPTIONS \ > $KERNEL_INC_OPTIONS -Wno-unused-value \ > -Wno-pointer-sign -working-directory \ > $WORKING_DIR -c $CLANG_SOURCE -target bpf \ > -O2 -o -" > > In fact, util/llvm-utils.c has updated the default configuration as > below: > > #define CLANG_BPF_CMD_DEFAULT_TEMPLATE \ > "$CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS "\ > "-DLINUX_VERSION_CODE=$LINUX_VERSION_CODE " \ > "$CLANG_OPTIONS $PERF_BPF_INC_OPTIONS $KERNEL_INC_OPTIONS " \ > "-Wno-unused-value -Wno-pointer-sign " \ > "-working-directory $WORKING_DIR " \ > "-c \"$CLANG_SOURCE\" -target bpf $CLANG_EMIT_LLVM -O2 -o - > $LLVM_OPTIONS_PIPE" > > Maybe should update Documentation/perf-config.txt to tell users the > real default value of clang-bpf-cmd-template?
Sure, if you fell like doing this, please update and also please figure out when the this changed and add a Fixes: that cset, Its great that you're going thru the docs and making sure the differences are noted so that we update the docs, thanks a lot! - Arnaldo
