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[83.244.142.114]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4a0017652d1sm144207825e9.5.2026.09.27.18.02.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 27 Sep 2026 18:02:42 -0700 (PDT) From: Michal Pluta To: acme@kernel.org, namhyung@kernel.org Cc: Peter Zijlstra , Ingo Molnar , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , James Clark , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 5/5] perf symbol: Move Rust demangling into its own function Date: Mon, 28 Sep 2026 02:02:27 +0100 Message-ID: <20260928010227.1903673-6-michalpl2003@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260928010227.1903673-1-michalpl2003@gmail.com> References: <20260928010227.1903673-1-michalpl2003@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit dso__demangle_sym() is the only place that implements demangling logic inline. The other three are one call each to a helper. Move the Rust parsing and buffer growth into rust_demangle_sym(), with the same signature as the other three. A Rust name that fails to demangle now falls through to the other demanglers, matching how the other demanglers chain into each other. A v0 name can't be misread by any of them, since none accepts its "_R" prefix. A legacy name can only fail here on allocation failure or hitting the output bound, neither of which is language-specific. Assisted-by: LLM Signed-off-by: Michal Pluta --- tools/perf/util/symbol.c | 61 +++++++++++++++++++++++----------------- 1 file changed, 35 insertions(+), 26 deletions(-) diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c index 858a14a91f79..89db9a670833 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -2740,47 +2740,56 @@ char *cxx_demangle_sym(const char *str __maybe_unused, bool params __maybe_unuse /* Buffer limit for a demangled Rust symbol name. */ #define RUST_DEMANGLE_MAX_LEN (1024 * 1024) -char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name) +static char *rust_demangle_sym(const char *elf_name) { struct demangle rust_demangle = { .style = DemangleStyleUnknown, }; char *demangled = NULL; size_t buf_len; + rust_demangle_demangle(elf_name, &rust_demangle); + if (!rust_demangle_is_known(&rust_demangle)) + return NULL; + + if (rust_demangle.mangled_len == 0) + return NULL; + + for (buf_len = min_t(size_t, roundup_pow_of_two(rust_demangle.mangled_len * 2), + RUST_DEMANGLE_MAX_LEN); + buf_len <= RUST_DEMANGLE_MAX_LEN; + buf_len *= 2) { + char *tmp = realloc(demangled, buf_len); + + if (!tmp) + break; + demangled = tmp; + if (rust_demangle_display_demangle(&rust_demangle, demangled, buf_len, + /*alternate=*/true) == OverflowOk) { + tmp = realloc(demangled, strlen(demangled) + 1); + return tmp ?: demangled; + } + } + /* Failure to grow output buffer or buffer exceeded sensible bounds. */ + free(demangled); + return NULL; +} + +char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name) +{ + char *demangled = NULL; + /* * We need to figure out if the object was created from C++ sources * DWARF DW_compile_unit has this, but we don't always have access * to it... */ if (!want_demangle((dso && dso__kernel(dso)) || kmodule)) return demangled; - rust_demangle_demangle(elf_name, &rust_demangle); - if (rust_demangle_is_known(&rust_demangle)) { - /* A rust mangled name. */ - if (rust_demangle.mangled_len == 0) - return demangled; - - for (buf_len = min_t(size_t, roundup_pow_of_two(rust_demangle.mangled_len * 2), - RUST_DEMANGLE_MAX_LEN); - buf_len <= RUST_DEMANGLE_MAX_LEN; - buf_len *= 2) { - char *tmp = realloc(demangled, buf_len); - - if (!tmp) - break; - demangled = tmp; - if (rust_demangle_display_demangle(&rust_demangle, demangled, buf_len, - /*alternate=*/true) == OverflowOk) { - tmp = realloc(demangled, strlen(demangled) + 1); - return tmp ?: demangled; - } - } - /* Failure to grow output buffer or buffer exceeded sensible bounds. */ - free(demangled); - return NULL; - } + demangled = rust_demangle_sym(elf_name); + if (demangled) + return demangled; demangled = cxx_demangle_sym(elf_name, verbose > 0, verbose > 0); if (demangled) -- 2.43.0