Messages in this thread Patch in this message | | | From | Ian Rogers <> | Date | Thu, 30 Mar 2023 12:03:53 -0700 | Subject | Re: [PATCH v1 09/13] perf symbol: Add abi::__cxa_demangle C++ demangling support |
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On Thu, Mar 30, 2023 at 9:50 AM Ian Rogers <irogers@google.com> wrote: > > On Thu, Mar 30, 2023 at 7:08 AM James Clark <james.clark@arm.com> wrote: > > > > > > > > On 11/03/2023 06:57, Ian Rogers wrote: > > > Refactor C++ demangling out of symbol-elf into its own files similar > > > to other languages. Add abi::__cxa_demangle support. As the other > > > demanglers are not shippable with distributions, this brings back C++ > > > demangling in a common case. It isn't perfect as the support for > > > optionally demangling arguments and modifiers isn't present. > > > > > > Signed-off-by: Ian Rogers <irogers@google.com> > > > --- > > > tools/perf/Makefile.config | 29 +++++++++--------- > > > tools/perf/util/Build | 1 + > > > tools/perf/util/demangle-cxx.cpp | 50 ++++++++++++++++++++++++++++++++ > > > tools/perf/util/demangle-cxx.h | 16 ++++++++++ > > > tools/perf/util/symbol-elf.c | 37 +++++------------------ > > > 5 files changed, 88 insertions(+), 45 deletions(-) > > > create mode 100644 tools/perf/util/demangle-cxx.cpp > > > create mode 100644 tools/perf/util/demangle-cxx.h > > > > > > diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config > > > index 5756498248e0..fdeca45cf15f 100644 > > > --- a/tools/perf/Makefile.config > > > +++ b/tools/perf/Makefile.config > > > @@ -906,6 +906,7 @@ ifdef BUILD_NONDISTRO > > > endif > > > > > > CFLAGS += -DHAVE_LIBBFD_SUPPORT > > > + CXXFLAGS += -DHAVE_LIBBFD_SUPPORT > > > ifeq ($(feature-libbfd-buildid), 1) > > > CFLAGS += -DHAVE_LIBBFD_BUILDID_SUPPORT > > > else > > > @@ -913,26 +914,24 @@ ifdef BUILD_NONDISTRO > > > endif > > > endif > > > > > > -ifdef NO_DEMANGLE > > > - CFLAGS += -DNO_DEMANGLE > > > -else > > > +ifndef NO_DEMANGLE > > > + $(call feature_check,cxa-demangle) > > > + ifeq ($(feature-cxa-demangle), 1) > > > + EXTLIBS += -lstdc++ > > > > Hi Ian, > > > > I think cross compilation for arm on x86 isn't working after this change > > (at least on Ubuntu). > > > > Even with all of the arm64 libstdc++ stuff installed, you can only link > > to it using g++, but the perf build tries to link to it using gcc. Not > > sure it's some quirk with the search paths on Ubuntu or something else: > > > > $ aarch64-linux-gnu-gcc -lstdc++ > > > > /usr/lib/gcc-cross/aarch64-linux-gnu/12/../../../../aarch64-linux- > > gnu/bin/ld: cannot find -lstdc++: No such file or directory > > collect2: error: ld returned 1 exit status > > > > g++ gets further: > > > > $ aarch64-linux-gnu-g++ -lstdc++ > > > > ... > > (.text+0x20): undefined reference to `main' > > collect2: error: ld returned 1 exit status > > > > At the end of the perf build it looks like something similar is > > happening (with all the non interesting bits deleted): > > > > $ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- -C tools/perf > > NO_BPF_SKEL=1 V=1 > > > > aarch64-linux-gnu-gcc ... -o perf > > > > /usr/lib/gcc-cross/aarch64-linux-gnu/12/../../../../aarch64-linux-gnu/bin/ld: > > cannot find -lstdc++: No such file or directory > > > > If I build with NO_DEMANGLE=1 then the build works, but I think it would > > at be best to autodetect rather than have to do this. Or maybe even link > > at the end with g++ if we're going to use libstdc++? > > Hi James, > > sorry for the problems you are having, I'll see if I can get a repo. I > did add a feature test with this change in the same set: > https://lore.kernel.org/lkml/20230311065753.3012826-9-irogers@google.com/ > So it should be feature testing and only enabling when > HAVE_CXA_DEMANGLE_SUPPORT is present. Obviously something is up, so > I'll have a think about it. > > Thanks, > Ian
Sorry to say I couldn't repro on Debian:
$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- -C tools/perf NO_LIBELF=1 NO_LIBTRACEEVENT=1 make: Entering directory '/home/irogers/kernel.org/tools/perf' BUILD: Doing 'make -j16' parallel build Warning: Kernel ABI header at 'tools/include/uapi/linux/in.h' differs from latest version at 'include/uapi/linux/in.h' diff -u tools/include/uapi/linux/in.h include/uapi/linux/in.h Warning: Kernel ABI header at 'tools/arch/x86/include/asm/cpufeatures.h' differs from latest version at 'arch/x86/include/asm/cpufeatures.h' diff -u tools/arch/x86/include/asm/cpufeatures.h arch/x86/include/asm/cpufeatures.h Warning: Kernel ABI header at 'tools/arch/arm64/include/uapi/asm/perf_regs.h' differs from latest version at 'arch/arm64/include/uapi/asm/perf_regs.h' diff -u tools/arch/arm64/include/uapi/asm/perf_regs.h arch/arm64/include/uapi/asm/perf_regs.h Warning: Kernel ABI header at 'tools/include/linux/coresight-pmu.h' differs from latest version at 'include/linux/coresight-pmu.h' diff -u tools/include/linux/coresight-pmu.h include/linux/coresight-pmu.h Makefile.config:588: No sys/sdt.h found, no SDT events are defined, please install systemtap-sdt-devel or systemtap-sdt-dev Makefile.config:679: Disabling post unwind, no support found. Makefile.config:747: No libcrypto.h found, disables jitted code injection, please install openssl-devel or libssl-dev Makefile.config:759: slang not found, disables TUI support. Please install slang-devel, libslang-devor libslang2-dev Makefile.config:806: Missing perl devel files. Disabling perl scripting support, please install perl-ExtUtils-Embed/libperl-dev Makefile.config:846: No 'Python.h' was found: disables Python support - please install python-devel/python-dev Makefile.config:951: No liblzma found, disables xz kernel module decompression, please install xz-devel/liblzma-dev Makefile.config:964: No libzstd found, disables trace compression, please install libzstd-dev[el] and/or set LIBZSTD_DIR Makefile.config:975: No libcap found, disables capability support, please install libcap-devel/libcap-dev Makefile.config:988: No numa.h found, disables 'perf bench numa mem' benchmark, please install numactl-devel/libnuma-devel/libnuma-dev Makefile.config:1047: No libbabeltrace found, disables 'perf data' CTF format support, please install libbabeltrace-dev[el]/libbabeltrace-ctf-dev Makefile.config:1138: libpfm4 not found, disables libpfm4 support. Please install libpfm4-dev
Auto-detecting system features: ... dwarf: [ OFF ] ... dwarf_getlocations: [ OFF ] ... glibc: [ on ] ... libbfd: [ OFF ] ... libbfd-buildid: [ OFF ] ... libcap: [ OFF ] ... libelf: [ OFF ] ... libnuma: [ OFF ] ... numa_num_possible_cpus: [ OFF ] ... libperl: [ OFF ] ... libpython: [ OFF ] ... libcrypto: [ OFF ] ... libunwind: [ OFF ] ... libdw-dwarf-unwind: [ OFF ] ... zlib: [ OFF ] ... lzma: [ OFF ] ... get_cpuid: [ OFF ] ... bpf: [ on ] ... libaio: [ on ] ... libzstd: [ OFF ]
INSTALL libsubcmd_headers INSTALL libsymbol_headers INSTALL libapi_headers INSTALL libperf_headers FLEX util/parse-events-flex.c FLEX util/pmu-flex.c CC util/pmu-bison.o FLEX util/expr-flex.c CC util/expr-bison.o CXX util/demangle-cxx.o CC util/demangle-ocaml.o CC util/demangle-java.o CC util/demangle-rust.o CC util/perf-hooks.o CC util/parse-events.o CC util/parse-events-flex.o CC util/pmu.o CC util/pmu-flex.o CC util/expr-flex.o CC util/expr.o LD util/perf-in.o LD perf-in.o LINK perf make: Leaving directory '.../tools/perf'
Thanks, Ian
> > Thanks > > James > > > > > + CFLAGS += -DHAVE_CXA_DEMANGLE_SUPPORT > > > + CXXFLAGS += -DHAVE_CXA_DEMANGLE_SUPPORT > > > + endif > > > ifdef BUILD_NONDISTRO > > > ifeq ($(filter -liberty,$(EXTLIBS)),) > > > - ifdef HAVE_CPLUS_DEMANGLE_SUPPORT > > > + $(call feature_check,cplus-demangle) > > > + ifeq ($(feature-cplus-demangle), 1) > > > EXTLIBS += -liberty > > > - else > > > - $(call feature_check,cplus-demangle) > > > - ifeq ($(feature-cplus-demangle), 1) > > > - EXTLIBS += -liberty > > > - endif > > > endif > > > endif > > > - endif > > > - > > > - ifneq ($(filter -liberty,$(EXTLIBS)),) > > > - CFLAGS += -DHAVE_CPLUS_DEMANGLE_SUPPORT > > > - else > > > - CFLAGS += -DNO_DEMANGLE > > > + ifneq ($(filter -liberty,$(EXTLIBS)),) > > > + CFLAGS += -DHAVE_CPLUS_DEMANGLE_SUPPORT > > > + CXXFLAGS += -DHAVE_CPLUS_DEMANGLE_SUPPORT > > > + endif > > > endif > > > endif > > > > > > diff --git a/tools/perf/util/Build b/tools/perf/util/Build > > > index 918b501f9bd8..8607575183a9 100644 > > > --- a/tools/perf/util/Build > > > +++ b/tools/perf/util/Build > > > @@ -211,6 +211,7 @@ perf-$(CONFIG_ZSTD) += zstd.o > > > > > > perf-$(CONFIG_LIBCAP) += cap.o > > > > > > +perf-y += demangle-cxx.o > > > perf-y += demangle-ocaml.o > > > perf-y += demangle-java.o > > > perf-y += demangle-rust.o > > > diff --git a/tools/perf/util/demangle-cxx.cpp b/tools/perf/util/demangle-cxx.cpp > > > new file mode 100644 > > > index 000000000000..8708bcafd370 > > > --- /dev/null > > > +++ b/tools/perf/util/demangle-cxx.cpp > > > @@ -0,0 +1,50 @@ > > > +// SPDX-License-Identifier: GPL-2.0 > > > +#include "demangle-cxx.h" > > > +#include <stdlib.h> > > > +#include <string.h> > > > +#include <linux/compiler.h> > > > + > > > +#ifdef HAVE_LIBBFD_SUPPORT > > > +#define PACKAGE 'perf' > > > +#include <bfd.h> > > > +#endif > > > + > > > +#ifdef HAVE_CXA_DEMANGLE_SUPPORT > > > +#include <cxxabi.h> > > > +#endif > > > + > > > +#if defined(HAVE_LIBBFD_SUPPORT) || defined(HAVE_CPLUS_DEMANGLE_SUPPORT) > > > +#ifndef DMGL_PARAMS > > > +#define DMGL_PARAMS (1 << 0) /* Include function args */ > > > +#define DMGL_ANSI (1 << 1) /* Include const, volatile, etc */ > > > +#endif > > > +#endif > > > + > > > +/* > > > + * Demangle C++ function signature > > > + * > > > + * Note: caller is responsible for freeing demangled string > > > + */ > > > +extern "C" > > > +char *cxx_demangle_sym(const char *str, bool params __maybe_unused, > > > + bool modifiers __maybe_unused) > > > +{ > > > +#ifdef HAVE_LIBBFD_SUPPORT > > > + int flags = (params ? DMGL_PARAMS : 0) | (modifiers ? DMGL_ANSI : 0); > > > + > > > + return bfd_demangle(NULL, str, flags); > > > +#elif defined(HAVE_CPLUS_DEMANGLE_SUPPORT) > > > + int flags = (params ? DMGL_PARAMS : 0) | (modifiers ? DMGL_ANSI : 0); > > > + > > > + return cplus_demangle(str, flags); > > > +#elif defined(HAVE_CXA_DEMANGLE_SUPPORT) > > > + size_t len = strlen(str); > > > + char *output = (char*)malloc(len); > > > + int status; > > > + > > > + output = abi::__cxa_demangle(str, output, &len, &status); > > > + return output; > > > +#else > > > + return NULL; > > > +#endif > > > +} > > > diff --git a/tools/perf/util/demangle-cxx.h b/tools/perf/util/demangle-cxx.h > > > new file mode 100644 > > > index 000000000000..26b5b66c0b4e > > > --- /dev/null > > > +++ b/tools/perf/util/demangle-cxx.h > > > @@ -0,0 +1,16 @@ > > > +/* SPDX-License-Identifier: GPL-2.0 */ > > > +#ifndef __PERF_DEMANGLE_CXX > > > +#define __PERF_DEMANGLE_CXX 1 > > > + > > > +#ifdef __cplusplus > > > +extern "C" { > > > +#endif > > > + > > > +char *cxx_demangle_sym(const char *str, bool params, bool modifiers); > > > + > > > +#ifdef __cplusplus > > > +} > > > +#endif > > > + > > > + > > > +#endif /* __PERF_DEMANGLE_CXX */ > > > diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c > > > index 41882ae8452e..c0a2de42c51b 100644 > > > --- a/tools/perf/util/symbol-elf.c > > > +++ b/tools/perf/util/symbol-elf.c > > > @@ -12,6 +12,7 @@ > > > #include "maps.h" > > > #include "symbol.h" > > > #include "symsrc.h" > > > +#include "demangle-cxx.h" > > > #include "demangle-ocaml.h" > > > #include "demangle-java.h" > > > #include "demangle-rust.h" > > > @@ -25,6 +26,11 @@ > > > #include <symbol/kallsyms.h> > > > #include <internal/lib.h> > > > > > > +#ifdef HAVE_LIBBFD_SUPPORT > > > +#define PACKAGE 'perf' > > > +#include <bfd.h> > > > +#endif > > > + > > > #ifndef EM_AARCH64 > > > #define EM_AARCH64 183 /* ARM 64 bit */ > > > #endif > > > @@ -45,34 +51,6 @@ > > > > > > typedef Elf64_Nhdr GElf_Nhdr; > > > > > > -#ifndef DMGL_PARAMS > > > -#define DMGL_NO_OPTS 0 /* For readability... */ > > > -#define DMGL_PARAMS (1 << 0) /* Include function args */ > > > -#define DMGL_ANSI (1 << 1) /* Include const, volatile, etc */ > > > -#endif > > > - > > > -#ifdef HAVE_LIBBFD_SUPPORT > > > -#define PACKAGE 'perf' > > > -#include <bfd.h> > > > -#else > > > -#ifdef HAVE_CPLUS_DEMANGLE_SUPPORT > > > -extern char *cplus_demangle(const char *, int); > > > - > > > -static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i) > > > -{ > > > - return cplus_demangle(c, i); > > > -} > > > -#else > > > -#ifdef NO_DEMANGLE > > > -static inline char *bfd_demangle(void __maybe_unused *v, > > > - const char __maybe_unused *c, > > > - int __maybe_unused i) > > > -{ > > > - return NULL; > > > -} > > > -#endif > > > -#endif > > > -#endif > > > > > > #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT > > > static int elf_getphdrnum(Elf *elf, size_t *dst) > > > @@ -295,7 +273,6 @@ static bool want_demangle(bool is_kernel_sym) > > > > > > static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name) > > > { > > > - int demangle_flags = verbose > 0 ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS; > > > char *demangled = NULL; > > > > > > /* > > > @@ -306,7 +283,7 @@ static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name) > > > if (!want_demangle(dso->kernel || kmodule)) > > > return demangled; > > > > > > - demangled = bfd_demangle(NULL, elf_name, demangle_flags); > > > + demangled = cxx_demangle_sym(elf_name, verbose > 0, verbose > 0); > > > if (demangled == NULL) { > > > demangled = ocaml_demangle_sym(elf_name); > > > if (demangled == NULL) {
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