From: Ian Rogers <irogers@google.com>
To: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Namhyung Kim <namhyung@kernel.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@kernel.org>,
Adrian Hunter <adrian.hunter@intel.com>,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <nick.desaulniers+lkml@gmail.com>,
Bill Wendling <morbo@google.com>,
Justin Stitt <justinstitt@google.com>,
Charlie Jenkins <charlie@rivosinc.com>,
"Masami Hiramatsu (Google)" <mhiramat@kernel.org>,
James Clark <james.clark@linaro.org>,
Collin Funk <collin.funk1@gmail.com>,
Dmitry Vyukov <dvyukov@google.com>,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
llvm@lists.linux.dev
Cc: Ian Rogers <irogers@google.com>
Subject: [PATCH v9 3/3] perf llvm: Mangle libperf-llvm.so function names
Date: Mon, 26 Jan 2026 22:23:02 -0800 [thread overview]
Message-ID: <20260127062302.544809-4-irogers@google.com> (raw)
In-Reply-To: <20260127062302.544809-1-irogers@google.com>
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 <irogers@google.com>
---
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 30e16a564d60..dafe5a6b8c0f 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -996,7 +996,8 @@ $(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<decltype(fn)>(dlsym(handle, "llvm_addr2line"));
+ fn = reinterpret_cast<decltype(fn)>(
+ 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<decltype(fn)>(dlsym(handle, "llvm_name_for_code"));
+ fn = reinterpret_cast<decltype(fn)>(
+ 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<decltype(fn)>(dlsym(handle, "llvm_name_for_data"));
+ fn = reinterpret_cast<decltype(fn)>(
+ 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
}
--
2.52.0.457.g6b5491de43-goog
next prev parent reply other threads:[~2026-01-27 6:23 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-27 6:22 [PATCH v9 0/3] Capstone/llvm dlopen support Ian Rogers
2026-01-27 6:23 ` [PATCH v9 1/3] perf capstone: Support for dlopen-ing libcapstone.so Ian Rogers
2026-01-28 18:47 ` Arnaldo Carvalho de Melo
2026-01-30 18:59 ` Ian Rogers
2026-01-30 23:38 ` Ian Rogers
2026-01-27 6:23 ` [PATCH v9 2/3] perf llvm: Support for dlopen-ing libLLVM.so Ian Rogers
2026-01-27 6:23 ` Ian Rogers [this message]
2026-01-27 17:12 ` [PATCH v9 0/3] Capstone/llvm dlopen support Arnaldo Carvalho de Melo
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