[PATCH 0/4] perf-probe: Improbe non-C language support

[Masami Hiramatsu (Google)]

Hi,

Here is a series of patches for perf probe to improve non-C language
(e.g. Rust, Go) support.

The non-C symbols are demangled style in debuginfo, e.g. golang stores

----
$ ./perf probe -x /work/go/example/outyet/main -F main*
main.(*Server).ServeHTTP
main.(*Server).ServeHTTP.Print.func1
main.(*Server).poll
...
-----

And Rust stores
-----
$ ./perf probe -x /work/cro3/target/x86_64-unknown-linux-gnu/debug/cro3 -F cro3::cmd::servo*
cro3::cmd::servo::run
cro3::cmd::servo::run::CALLSITE
cro3::cmd::servo::run::CALLSITE::META
cro3::cmd::servo::run_control
-----

These symbols are not parsed correctly because it looks like a file name or
including line numbers (`:` caused it.) So, I decided to introduce the changes

 - filename MUST start from '@'. (so it is able to distinguish the filename
   and the function name)
 - Fix to allow backslash to escape to --lines option.
 - Introduce quotation mark support.
 - Replace non-alnum character to '_' for event name (for non-C symbols).

With these changes, we can run -L (--lines) on golang;

------
$ perf probe -x goexample/hello/hello -L \"main.main\"
<main.main@/work/goexample/hello/hello.go:0>
      0  func main() {
                // Configure logging for a command-line program.
      2         log.SetFlags(0)
      3         log.SetPrefix("hello: ")

                // Parse flags.
      6         flag.Usage = usage
      7         flag.Parse()
------

And Rust
------
$ perf probe -x cro3 -L \"cro3::cmd::servo::run_show\"
<run_show@/work/cro3/src/cmd/servo.rs:0>
      0  fn run_show(args: &ArgsShow) -> Result<()> {
      1      let list = ServoList::discover()?;
      2      let s = list.find_by_serial(&args.servo)?;
      3      if args.json {
      4          println!("{s}");
------

And event name are created automatically like below;

$ ./perf probe -x /work/go/example/outyet/main -D 'main.(*Server).poll'
p:probe_main/main_Server_poll /work/go/example/outyet/main:0x353040

$ ./perf probe -x cro3 -D \"cro3::cmd::servo::run_show\"
p:probe_cro3/cro3_cmd_servo_run_show /work/cro3/target/x86_64-unknown-linux-gnu/debug/cro3:0x197530

We still need some more work, but these shows how perf-probe can work
with other languages.

Thank you,

---

Masami Hiramatsu (Google) (4):
      perf-probe: Fix to ignore escaped characters in --lines option
      perf-probe: Require '@' prefix for filename always
      perf-probe: Introduce quotation marks support
      perf-probe: Replace unacceptable characters when generating event name


 tools/perf/util/probe-event.c  |  136 ++++++++++++++++++++++------------------
 tools/perf/util/probe-finder.c |    3 +
 tools/perf/util/string.c       |  100 +++++++++++++++++++++++++++++
 tools/perf/util/string2.h      |    2 +
 4 files changed, 180 insertions(+), 61 deletions(-)

--
Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>