[PATCH v2 00/17] Support dynamic opening of capstone/llvm remove BUILD_NONDISTRO

Ian Rogers
2025-01-22T06:23:45Z

Linking against libcapstone and libLLVM can be a significant increase
in dependencies and size of memory footprint. For something like `perf
record` the disassembler and addr2line functionality won't be
used. Support dynamically loading these libraries using dlopen and
then calling the appropriate functions found using dlsym.

BUILD_NONDISTRO is used to build perf against the license incompatible
libbfd and libiberty libraries. As this has been opt-in for nearly 2
years, commit dd317df07207 ("perf build: Make binutil libraries opt
in"), remove the code to simplify the code base.

The patch series:
1) does some initial clean up;
2) moves the capstone and LLVM code to their own C files,
3) simplifies a little the capstone code;
4) adds perf_ variants of the functions that will either directly call
the function or use dlsym to discover it;
5) adds BPF JIT disassembly support to LLVM and capstone disassembly;
6) removes the BUILD_NONDISTRO code, reduces scope and removes what's possible.

The addr2line LLVM functionality is written in C++. To avoid linking
against libLLVM for this, a new LIBLLVM_DYNAMIC option is added where
the C++ code with the libLLVM dependency will be built into a
libperf-llvm.so and that dlsym-ed and called against. Ideally LLVM
would extend their C API to avoid this.

The libbfd BPF disassembly supported source lines, this wasn't ported
to the capstone and LLVM disassembly.

v2: Add mangling of the function names in libperf-llvm.so to avoid
potential infinite recursion. Add BPF JIT disassembly support to
LLVM and capstone. Add/rebase the BUILD_NONDISTRO cleanup onto the
series from:
https://lore.kernel.org/lkml/20250111202851.1075338-1-irogers@google.com/
Some other minor additional clean up.

Ian Rogers (17):
perf build: Remove libtracefs configuration
perf map: Constify objdump offset/address conversion APIs
perf capstone: Move capstone functionality into its own file
perf llvm: Move llvm functionality into its own file
perf capstone: Remove open_capstone_handle
perf capstone: Support for dlopen-ing libcapstone.so
perf llvm: Support for dlopen-ing libLLVM.so
perf llvm: Mangle libperf-llvm.so function names
perf dso: Move read_symbol from llvm/capstone to dso
perf dso: Support BPF programs in dso__read_symbol
perf llvm: Disassemble cleanup
perf dso: Clean up read_symbol error handling
perf build: Remove libbfd support
perf build: Remove libiberty support
perf build: Remove unused defines
perf disasm: Remove disasm_bpf
perf disasm: Make ins__scnprintf and ins__is_nop static

tools/perf/Documentation/perf-check.txt | 1 -
tools/perf/Makefile.config | 90 +---
tools/perf/Makefile.perf | 35 +-
tools/perf/builtin-check.c | 1 -
tools/perf/builtin-script.c | 2 -
tools/perf/tests/Build | 1 -
tools/perf/tests/builtin-test.c | 1 -
tools/perf/tests/make | 4 +-
tools/perf/tests/pe-file-parsing.c | 101 ----
tools/perf/tests/tests.h | 1 -
tools/perf/util/Build | 5 +-
tools/perf/util/annotate.h | 1 -
tools/perf/util/capstone.c | 682 ++++++++++++++++++++++++
tools/perf/util/capstone.h | 24 +
tools/perf/util/demangle-cxx.cpp | 22 +-
tools/perf/util/disasm.c | 632 +---------------------
tools/perf/util/disasm.h | 5 +-
tools/perf/util/disasm_bpf.c | 195 -------
tools/perf/util/disasm_bpf.h | 12 -
tools/perf/util/dso.c | 98 ++++
tools/perf/util/dso.h | 4 +
tools/perf/util/llvm-c-helpers.cpp | 120 ++++-
tools/perf/util/llvm-c-helpers.h | 24 +-
tools/perf/util/llvm.c | 489 +++++++++++++++++
tools/perf/util/llvm.h | 24 +
tools/perf/util/map.c | 19 +-
tools/perf/util/map.h | 6 +-
tools/perf/util/print_insn.c | 117 +---
tools/perf/util/srcline.c | 306 +----------
tools/perf/util/srcline.h | 6 +
tools/perf/util/symbol-elf.c | 95 ----
tools/perf/util/symbol.c | 135 -----
tools/perf/util/symbol.h | 4 -
33 files changed, 1552 insertions(+), 1710 deletions(-)
delete mode 100644 tools/perf/tests/pe-file-parsing.c
create mode 100644 tools/perf/util/capstone.c
create mode 100644 tools/perf/util/capstone.h
delete mode 100644 tools/perf/util/disasm_bpf.c
delete mode 100644 tools/perf/util/disasm_bpf.h
create mode 100644 tools/perf/util/llvm.c
create mode 100644 tools/perf/util/llvm.h