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AJvYcCX+91BOtij9AAe6w+T+gkebK8O7E57EhCnwgJGgM51hJbxtG2frM5V2ZklSAsSM8YgxVh004sNl8D80dkmpBXyU@vger.kernel.org X-Gm-Message-State: AOJu0YwebdRoWQ6gLxgeynAJsTfi5RWSVzjpM0RRjWROej1cNZVDMw43 PLreEE9uavwVT5H9dTnkVgGAm6aMKUwJZ1LiJwURVJh7Y73JK+ZwxjUZLSNaQEO32RQGzWW6NOn vObF3Lnx58g== X-Google-Smtp-Source: AGHT+IGZO8H4JLpFgt1/0MVyoB9Uqa4UugryjMaoOCLJw8jlXl8/35ep01Y5UvG/XDtrEKHxSP6ttmMCTZDF X-Received: from pjbbx13.prod.google.com ([2002:a17:90a:f48d:b0:332:7fae:e138]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:4d82:b0:332:afb1:d050 with SMTP id 98e67ed59e1d1-3342a28c02amr19221287a91.14.1759172943374; Mon, 29 Sep 2025 12:09:03 -0700 (PDT) Date: Mon, 29 Sep 2025 12:07:58 -0700 In-Reply-To: <20250929190805.201446-1-irogers@google.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250929190805.201446-1-irogers@google.com> X-Mailer: git-send-email 2.51.0.570.gb178f27e6d-goog Message-ID: <20250929190805.201446-9-irogers@google.com> Subject: [PATCH v6 08/15] perf llvm: Mangle libperf-llvm.so function names From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt , Charlie Jenkins , Eric Biggers , "Masami Hiramatsu (Google)" , James Clark , Collin Funk , "Dr. David Alan Gilbert" , Li Huafei , Athira Rajeev , Stephen Brennan , Dmitry Vyukov , Alexandre Ghiti , Haibo Xu , Andi Kleen , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, bpf@vger.kernel.org, llvm@lists.linux.dev, Song Liu Content-Type: text/plain; charset="UTF-8" For a function like llvm_addr2line having the libperf-llvm.so exported symbol named llvm_addr2line meant that the perf llvm_addr2line could sometimes erroneously be returned. This led to infinite recursion and eventual stack overflow. To avoid this conflict add a new BUILDING_PERF_LLVMSO when libperf-llvm.so is being built and use it to alter the behavior of MANGLE_PERF_LLVM_API, a macro that prefixes the name when libperf-llvm.so is being built. The prefixed named avoids the name collision. Signed-off-by: Ian Rogers --- tools/perf/Makefile.perf | 3 ++- tools/perf/util/llvm-c-helpers.cpp | 29 ++++++++++++++++++----------- tools/perf/util/llvm-c-helpers.h | 24 ++++++++++++++++-------- 3 files changed, 36 insertions(+), 20 deletions(-) diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf index bfa4ad7ea89d..116c935c06f7 100644 --- a/tools/perf/Makefile.perf +++ b/tools/perf/Makefile.perf @@ -1002,7 +1002,8 @@ $(LIBSYMBOL)-clean: $(Q)$(RM) -r -- $(LIBSYMBOL_OUTPUT) ifdef LIBLLVM_DYNAMIC -LIBPERF_LLVM_CXXFLAGS := $(call filter-out,-DHAVE_LIBLLVM_DYNAMIC,$(CXXFLAGS)) -DHAVE_LIBLLVM_SUPPORT +LIBPERF_LLVM_CXXFLAGS := $(call filter-out,-DHAVE_LIBLLVM_DYNAMIC,$(CXXFLAGS)) +LIBPERF_LLVM_CXXFLAGS += -DHAVE_LIBLLVM_SUPPORT -DBUILDING_PERF_LLVMSO LIBPERF_LLVM_LIBS = -L$(shell $(LLVM_CONFIG) --libdir) $(LIBLLVM) -lstdc++ $(OUTPUT)$(LIBPERF_LLVM): util/llvm-c-helpers.cpp diff --git a/tools/perf/util/llvm-c-helpers.cpp b/tools/perf/util/llvm-c-helpers.cpp index 5a6f76e6b705..8cea380be5c2 100644 --- a/tools/perf/util/llvm-c-helpers.cpp +++ b/tools/perf/util/llvm-c-helpers.cpp @@ -99,10 +99,12 @@ static int extract_file_and_line(const DILineInfo &line_info, char **file, #endif extern "C" -int llvm_addr2line(const char *dso_name __maybe_unused, u64 addr __maybe_unused, - char **file __maybe_unused, unsigned int *line __maybe_unused, - bool unwind_inlines __maybe_unused, - llvm_a2l_frame **inline_frames __maybe_unused) +int MANGLE_PERF_LLVM_API(llvm_addr2line)(const char *dso_name __maybe_unused, + u64 addr __maybe_unused, + char **file __maybe_unused, + unsigned int *line __maybe_unused, + bool unwind_inlines __maybe_unused, + llvm_a2l_frame **inline_frames __maybe_unused) { #if defined(HAVE_LIBLLVM_SUPPORT) && !defined(HAVE_LIBLLVM_DYNAMIC) LLVMSymbolizer *symbolizer = get_symbolizer(); @@ -177,7 +179,8 @@ int llvm_addr2line(const char *dso_name __maybe_unused, u64 addr __maybe_unused, if (!handle) return 0; - fn = reinterpret_cast(dlsym(handle, "llvm_addr2line")); + fn = reinterpret_cast( + dlsym(handle, MANGLE_PERF_LLVM_API_STR(llvm_addr2line))); if (!fn) pr_debug("dlsym failed for llvm_addr2line\n"); fn_init = true; @@ -215,8 +218,9 @@ make_symbol_relative_string(struct dso *dso, const char *sym_name, #endif extern "C" -char *llvm_name_for_code(struct dso *dso __maybe_unused, const char *dso_name __maybe_unused, - u64 addr __maybe_unused) +char *MANGLE_PERF_LLVM_API(llvm_name_for_code)(struct dso *dso __maybe_unused, + const char *dso_name __maybe_unused, + u64 addr __maybe_unused) { #if defined(HAVE_LIBLLVM_SUPPORT) && !defined(HAVE_LIBLLVM_DYNAMIC) LLVMSymbolizer *symbolizer = get_symbolizer(); @@ -242,7 +246,8 @@ char *llvm_name_for_code(struct dso *dso __maybe_unused, const char *dso_name __ if (!handle) return NULL; - fn = reinterpret_cast(dlsym(handle, "llvm_name_for_code")); + fn = reinterpret_cast( + dlsym(handle, MANGLE_PERF_LLVM_API_STR(llvm_name_for_code))); if (!fn) pr_debug("dlsym failed for llvm_name_for_code\n"); fn_init = true; @@ -256,8 +261,9 @@ char *llvm_name_for_code(struct dso *dso __maybe_unused, const char *dso_name __ } extern "C" -char *llvm_name_for_data(struct dso *dso __maybe_unused, const char *dso_name __maybe_unused, - u64 addr __maybe_unused) +char *MANGLE_PERF_LLVM_API(llvm_name_for_data)(struct dso *dso __maybe_unused, + const char *dso_name __maybe_unused, + u64 addr __maybe_unused) { #if defined(HAVE_LIBLLVM_SUPPORT) && !defined(HAVE_LIBLLVM_DYNAMIC) LLVMSymbolizer *symbolizer = get_symbolizer(); @@ -283,7 +289,8 @@ char *llvm_name_for_data(struct dso *dso __maybe_unused, const char *dso_name __ if (!handle) return NULL; - fn = reinterpret_cast(dlsym(handle, "llvm_name_for_data")); + fn = reinterpret_cast( + dlsym(handle, MANGLE_PERF_LLVM_API_STR(llvm_name_for_data))); if (!fn) pr_debug("dlsym failed for llvm_name_for_data\n"); fn_init = true; diff --git a/tools/perf/util/llvm-c-helpers.h b/tools/perf/util/llvm-c-helpers.h index d2b99637a28a..cfcfd540cdae 100644 --- a/tools/perf/util/llvm-c-helpers.h +++ b/tools/perf/util/llvm-c-helpers.h @@ -13,6 +13,14 @@ extern "C" { #endif +/* Support name mangling so that libperf_llvm.so's names don't match those in perf. */ +#ifdef BUILDING_PERF_LLVMSO +#define MANGLE_PERF_LLVM_API(x) PERF_LLVM_SO_ ## x +#else +#define MANGLE_PERF_LLVM_API(x) x +#endif +#define MANGLE_PERF_LLVM_API_STR(x) "PERF_LLVM_SO_" #x + struct dso; struct llvm_a2l_frame { @@ -37,12 +45,12 @@ struct llvm_a2l_frame { * a newly allocated array with that length. The caller is then responsible * for freeing both the strings and the array itself. */ -int llvm_addr2line(const char* dso_name, - u64 addr, - char** file, - unsigned int* line, - bool unwind_inlines, - struct llvm_a2l_frame** inline_frames); +int MANGLE_PERF_LLVM_API(llvm_addr2line)(const char *dso_name, + u64 addr, + char **file, + unsigned int *line, + bool unwind_inlines, + struct llvm_a2l_frame **inline_frames); /* * Simple symbolizers for addresses; will convert something like @@ -50,8 +58,8 @@ int llvm_addr2line(const char* dso_name, * * The returned value must be freed by the caller, with free(). */ -char *llvm_name_for_code(struct dso *dso, const char *dso_name, u64 addr); -char *llvm_name_for_data(struct dso *dso, const char *dso_name, u64 addr); +char *MANGLE_PERF_LLVM_API(llvm_name_for_code)(struct dso *dso, const char *dso_name, u64 addr); +char *MANGLE_PERF_LLVM_API(llvm_name_for_data)(struct dso *dso, const char *dso_name, u64 addr); #ifdef __cplusplus } -- 2.51.0.570.gb178f27e6d-goog