From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4E4A4C77B60 for ; Thu, 30 Mar 2023 14:08:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231864AbjC3OIz (ORCPT ); Thu, 30 Mar 2023 10:08:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58756 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231854AbjC3OIq (ORCPT ); Thu, 30 Mar 2023 10:08:46 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id ABDF59753; Thu, 30 Mar 2023 07:08:35 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8B5C12F4; Thu, 30 Mar 2023 07:09:07 -0700 (PDT) Received: from [192.168.1.158] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 691093F663; Thu, 30 Mar 2023 07:08:20 -0700 (PDT) Message-ID: Date: Thu, 30 Mar 2023 15:08:15 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.9.0 Subject: Re: [PATCH v1 09/13] perf symbol: Add abi::__cxa_demangle C++ demangling support Content-Language: en-US To: Ian Rogers , Arnaldo Carvalho de Melo Cc: Stephane Eranian , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Nathan Chancellor , Nick Desaulniers , Tom Rix , Roberto Sassu , Quentin Monnet , Andres Freund , Tiezhu Yang , Pavithra Gurushankar , Yang Jihong , Adrian Hunter , Leo Yan , =?UTF-8?Q?Martin_Li=c5=a1ka?= , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, llvm@lists.linux.dev, Peter Zijlstra , Ingo Molnar References: <20230311065753.3012826-1-irogers@google.com> <20230311065753.3012826-10-irogers@google.com> From: James Clark In-Reply-To: <20230311065753.3012826-10-irogers@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 > --- > 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++? 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 > +#include > +#include > + > +#ifdef HAVE_LIBBFD_SUPPORT > +#define PACKAGE 'perf' > +#include > +#endif > + > +#ifdef HAVE_CXA_DEMANGLE_SUPPORT > +#include > +#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 > #include > > +#ifdef HAVE_LIBBFD_SUPPORT > +#define PACKAGE 'perf' > +#include > +#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 > -#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) {