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Subject[PATCH v2 4/5] perf-probe: Find versioned symbols from map
Date
Find versioned symbols correctly from map.
Commit d80406453ad4 ("perf symbols: Allow user probes on
versioned symbols") allows user to find default versioned
symbols (with "@@") in map. However, it did not enable
normal versioned symbol (with "@") for perf-probe.
E.g.

=====
# ./perf probe -x /lib64/libc-2.25.so malloc_get_state
Failed to find symbol malloc_get_state in /usr/lib64/libc-2.25.so
Error: Failed to add events.
=====

This solves above issue by improving perf-probe symbol
search function, as below.

=====
# ./perf probe -x /lib64/libc-2.25.so malloc_get_state
Added new event:
probe_libc:malloc_get_state (on malloc_get_state in /usr/lib64/libc-2.25.so)

You can now use it in all perf tools, such as:

perf record -e probe_libc:malloc_get_state -aR sleep 1

# ./perf probe -l
probe_libc:malloc_get_state (on malloc_get_state@GLIBC_2.2.5 in /usr/lib64/libc-2.25.so)
=====

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
tools/perf/arch/powerpc/util/sym-handling.c | 8 ++++++++
tools/perf/util/probe-event.c | 16 +++++++++++++++-
tools/perf/util/symbol.c | 5 +++++
tools/perf/util/symbol.h | 1 +
4 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/tools/perf/arch/powerpc/util/sym-handling.c b/tools/perf/arch/powerpc/util/sym-handling.c
index 9c4e23d8c8ce..a3613c8d97b6 100644
--- a/tools/perf/arch/powerpc/util/sym-handling.c
+++ b/tools/perf/arch/powerpc/util/sym-handling.c
@@ -64,6 +64,14 @@ int arch__compare_symbol_names_n(const char *namea, const char *nameb,

return strncmp(namea, nameb, n);
}
+
+const char *arch__normalize_symbol_name(const char *name)
+{
+ /* Skip over initial dot */
+ if (*name == '.')
+ name++;
+ return name;
+}
#endif

#if defined(_CALL_ELF) && _CALL_ELF == 2
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 959c4d2ef455..94acc5846e2a 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -2801,16 +2801,30 @@ static int find_probe_functions(struct map *map, char *name,
int found = 0;
struct symbol *sym;
struct rb_node *tmp;
+ const char *norm, *ver;
+ char *buf = NULL;

if (map__load(map) < 0)
return 0;

map__for_each_symbol(map, sym, tmp) {
- if (strglobmatch(sym->name, name)) {
+ norm = arch__normalize_symbol_name(sym->name);
+ if (!norm)
+ continue;
+
+ /* We don't care about default symbol or not */
+ ver = strchr(norm, '@');
+ if (ver) {
+ buf = strndup(norm, ver - norm);
+ norm = buf;
+ }
+ if (strglobmatch(norm, name)) {
found++;
if (syms && found < probe_conf.max_probes)
syms[found - 1] = sym;
}
+ if (buf)
+ zfree(&buf);
}

return found;
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 1b67a8639dfe..cc065d4bfafc 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -94,6 +94,11 @@ static int prefix_underscores_count(const char *str)
return tail - str;
}

+const char * __weak arch__normalize_symbol_name(const char *name)
+{
+ return name;
+}
+
int __weak arch__compare_symbol_names(const char *namea, const char *nameb)
{
return strcmp(namea, nameb);
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index a4f0075b4e5c..0563f33c1eb3 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -349,6 +349,7 @@ bool elf__needs_adjust_symbols(GElf_Ehdr ehdr);
void arch__sym_update(struct symbol *s, GElf_Sym *sym);
#endif

+const char *arch__normalize_symbol_name(const char *name);
#define SYMBOL_A 0
#define SYMBOL_B 1

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