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// Copyright 2014 The Rust Project Developers. See the COPYRIGHT // file at the top-level directory of this distribution and at // http://rust-lang.org/COPYRIGHT. // // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your // option. This file may not be copied, modified, or distributed // except according to those terms. //! This crate provides static instrumentation macros. //! //! With the `probe!` macro, programmers can place static instrumentation //! points in their code to mark events of interest. These are compiled into //! platform-specific implementations, e.g. SystemTap SDT on Linux. Probes are //! designed to have negligible overhead during normal operation, so they can //! be present in all builds, and only activated using those external tools. //! //! # Example //! //! This simple example instruments the beginning and end of program, as well //! as every iteration through the loop with arguments for the counter and //! intermediate total. //! //! ```rust //! #![feature(asm)] //! use probe::probe; //! fn main() { //! probe!(foo, begin); //! let mut total = 0; //! for i in 0..100 { //! total += i; //! probe!(foo, loop, i, total); //! } //! assert_eq!(total, 4950); //! probe!(foo, end); //! } //! ``` //! //! ## Using probes with SystemTap //! //! For the program above, a SystemTap script could double-check the totals: //! //! ```notrust //! global check //! //! probe process.provider("foo").mark("loop") { //! check += $arg1; //! if (check != $arg2) //! printf("foo total is out of sync! (%d != %d)\n", check, $arg2); //! } //! //! // .provider is optional //! probe process.mark("begin"), process.mark("end") { //! printf("%s:%s\n", $$provider, $$name); //! } //! ``` //! //! Since this program behaves as expected, this script will not have any complaint. //! //! ```notrust //! $ stap --dyninst foo.stp -c ./foo //! foo:begin //! foo:end //! ``` //! //! ## Using probes with GDB //! //! Starting in version 7.5, GDB can set breakpoints on probes and read arguments. //! //! ```notrust //! (gdb) info probes //! Provider Name Where Semaphore Object //! foo begin 0x0000000000402e70 /tmp/foo //! foo end 0x000000000040315c /tmp/foo //! foo loop 0x0000000000402f25 /tmp/foo //! (gdb) break -probe foo:loop //! Breakpoint 1 at 0x402f25 //! (gdb) condition 1 $_probe_arg1 > 1000 //! (gdb) run //! Starting program: /tmp/foo //! [Thread debugging using libthread_db enabled] //! Using host libthread_db library "/lib64/libthread_db.so.1". //! //! Breakpoint 1, 0x0000000000402f25 in main::hd67360886023c1c6faa::v0.0 () //! (gdb) print $_probe_arg0 //! $1 = 45 //! (gdb) print $_probe_arg1 //! $2 = 1035 //! ``` #![crate_name = "probe"] #![crate_type = "rlib"] #![doc(html_logo_url = "http://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png", html_favicon_url = "http://www.rust-lang.org/favicon.ico", html_root_url = "http://doc.rust-lang.org/nightly/")] #![feature(asm)] #![no_std] mod platform; /// Define a static probe point. /// /// This annotates a code location with a name and arguments, and compiles /// in metadata to let debugging tools locate it. /// /// # Arguments /// /// * `provider` - An identifier for naming probe groups. /// /// * `name` - An identifier for this specific probe. /// /// * `arg`... - Optional data to provide with the probe. Any expression which /// can be cast `as i64` is allowed as an argument. The arguments might not /// be evaluated at all when a debugger is not attached to the probe, /// depending on the platform implementation, so don't rely on side effects. /// /// # Example /// /// ``` /// #![feature(asm)] /// use probe::probe; /// fn main() { /// probe!(foo, main); /// /// let x = 42; /// probe!(foo, show_x, x); /// /// let y = Some(x); /// probe!(foo, show_y, match y { /// Some(n) => n, /// None => -1 /// }); /// } /// ``` #[macro_export] macro_rules! probe( ($provider:ident, $name:ident) => ($crate::platform_probe!($provider, $name,)); ($provider:ident, $name:ident, $($arg:expr),*) => ($crate::platform_probe!($provider, $name, $($arg),*)); );