rustc: Add a debug_assertions #[cfg] directive

This commit is an implementation of [RFC 563][rfc] which adds a new
`cfg(debug_assertions)` directive which is specially recognized and calculated
by the compiler. The flag is turned off at any optimization level greater than 1
and may also be explicitly controlled through the `-C debug-assertions`
flag.

[rfc]: https://github.com/rust-lang/rfcs/pull/563

The `debug_assert!` and `debug_assert_eq!` macros now respect this instead of
the `ndebug` variable and `ndebug` no longer holds any meaning to the standard
library.

Code which was previously relying on `not(ndebug)` to gate expensive code should
be updated to rely on `debug_assertions` instead.

Closes #22492
[breaking-change]
This commit is contained in:
Alex Crichton 2015-03-02 14:51:24 -08:00
parent 68740b4054
commit d5d834551c
13 changed files with 100 additions and 19 deletions

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@ -590,7 +590,7 @@ TEST_SREQ$(1)_T_$(2)_H_$(3) = \
# The tests select when to use debug configuration on their own; # The tests select when to use debug configuration on their own;
# remove directive, if present, from CFG_RUSTC_FLAGS (issue #7898). # remove directive, if present, from CFG_RUSTC_FLAGS (issue #7898).
CTEST_RUSTC_FLAGS := $$(subst --cfg ndebug,,$$(CFG_RUSTC_FLAGS)) CTEST_RUSTC_FLAGS := $$(subst -C debug-assertions,,$$(CFG_RUSTC_FLAGS))
# The tests cannot be optimized while the rest of the compiler is optimized, so # The tests cannot be optimized while the rest of the compiler is optimized, so
# filter out the optimization (if any) from rustc and then figure out if we need # filter out the optimization (if any) from rustc and then figure out if we need

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@ -100,10 +100,12 @@ macro_rules! assert_eq {
/// This will invoke the `panic!` macro if the provided expression cannot be /// This will invoke the `panic!` macro if the provided expression cannot be
/// evaluated to `true` at runtime. /// evaluated to `true` at runtime.
/// ///
/// Unlike `assert!`, `debug_assert!` statements can be disabled by passing /// Unlike `assert!`, `debug_assert!` statements are only enabled in non
/// `--cfg ndebug` to the compiler. This makes `debug_assert!` useful for /// optimized builds by default. An optimized build will omit all
/// checks that are too expensive to be present in a release build but may be /// `debug_assert!` statements unless `-C debug-assertions` is passed to the
/// helpful during development. /// compiler. This makes `debug_assert!` useful for checks that are too
/// expensive to be present in a release build but may be helpful during
/// development.
/// ///
/// # Example /// # Example
/// ///
@ -125,7 +127,7 @@ macro_rules! assert_eq {
#[macro_export] #[macro_export]
#[stable(feature = "rust1", since = "1.0.0")] #[stable(feature = "rust1", since = "1.0.0")]
macro_rules! debug_assert { macro_rules! debug_assert {
($($arg:tt)*) => (if cfg!(not(ndebug)) { assert!($($arg)*); }) ($($arg:tt)*) => (if cfg!(debug_assertions) { assert!($($arg)*); })
} }
/// Asserts that two expressions are equal to each other, testing equality in /// Asserts that two expressions are equal to each other, testing equality in
@ -133,10 +135,12 @@ macro_rules! debug_assert {
/// ///
/// On panic, this macro will print the values of the expressions. /// On panic, this macro will print the values of the expressions.
/// ///
/// Unlike `assert_eq!`, `debug_assert_eq!` statements can be disabled by /// Unlike `assert_eq!`, `debug_assert_eq!` statements are only enabled in non
/// passing `--cfg ndebug` to the compiler. This makes `debug_assert_eq!` /// optimized builds by default. An optimized build will omit all
/// useful for checks that are too expensive to be present in a release build /// `debug_assert_eq!` statements unless `-C debug-assertions` is passed to the
/// but may be helpful during development. /// compiler. This makes `debug_assert_eq!` useful for checks that are too
/// expensive to be present in a release build but may be helpful during
/// development.
/// ///
/// # Example /// # Example
/// ///
@ -147,7 +151,7 @@ macro_rules! debug_assert {
/// ``` /// ```
#[macro_export] #[macro_export]
macro_rules! debug_assert_eq { macro_rules! debug_assert_eq {
($($arg:tt)*) => (if cfg!(not(ndebug)) { assert_eq!($($arg)*); }) ($($arg:tt)*) => (if cfg!(debug_assertions) { assert_eq!($($arg)*); })
} }
/// Short circuiting evaluation on Err /// Short circuiting evaluation on Err

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@ -157,7 +157,7 @@ macro_rules! info {
/// ``` /// ```
#[macro_export] #[macro_export]
macro_rules! debug { macro_rules! debug {
($($arg:tt)*) => (if cfg!(not(ndebug)) { log!(::log::DEBUG, $($arg)*) }) ($($arg:tt)*) => (if cfg!(debug_assertions) { log!(::log::DEBUG, $($arg)*) })
} }
/// A macro to test whether a log level is enabled for the current module. /// A macro to test whether a log level is enabled for the current module.
@ -192,7 +192,7 @@ macro_rules! debug {
macro_rules! log_enabled { macro_rules! log_enabled {
($lvl:expr) => ({ ($lvl:expr) => ({
let lvl = $lvl; let lvl = $lvl;
(lvl != ::log::DEBUG || cfg!(not(ndebug))) && (lvl != ::log::DEBUG || cfg!(debug_assertions)) &&
lvl <= ::log::log_level() && lvl <= ::log::log_level() &&
::log::mod_enabled(lvl, module_path!()) ::log::mod_enabled(lvl, module_path!())
}) })

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@ -81,6 +81,7 @@ pub struct Options {
pub gc: bool, pub gc: bool,
pub optimize: OptLevel, pub optimize: OptLevel,
pub debug_assertions: bool,
pub debuginfo: DebugInfoLevel, pub debuginfo: DebugInfoLevel,
pub lint_opts: Vec<(String, lint::Level)>, pub lint_opts: Vec<(String, lint::Level)>,
pub describe_lints: bool, pub describe_lints: bool,
@ -238,7 +239,8 @@ pub fn basic_options() -> Options {
crate_name: None, crate_name: None,
alt_std_name: None, alt_std_name: None,
libs: Vec::new(), libs: Vec::new(),
unstable_features: UnstableFeatures::Disallow unstable_features: UnstableFeatures::Disallow,
debug_assertions: true,
} }
} }
@ -528,6 +530,8 @@ options! {CodegenOptions, CodegenSetter, basic_codegen_options,
2 = full debug info with variable and type information"), 2 = full debug info with variable and type information"),
opt_level: Option<uint> = (None, parse_opt_uint, opt_level: Option<uint> = (None, parse_opt_uint,
"Optimize with possible levels 0-3"), "Optimize with possible levels 0-3"),
debug_assertions: Option<bool> = (None, parse_opt_bool,
"explicitly enable the cfg(debug_assertions) directive"),
} }
@ -621,7 +625,7 @@ pub fn default_configuration(sess: &Session) -> ast::CrateConfig {
}; };
let mk = attr::mk_name_value_item_str; let mk = attr::mk_name_value_item_str;
return vec!(// Target bindings. let mut ret = vec![ // Target bindings.
attr::mk_word_item(fam.clone()), attr::mk_word_item(fam.clone()),
mk(InternedString::new("target_os"), intern(os)), mk(InternedString::new("target_os"), intern(os)),
mk(InternedString::new("target_family"), fam), mk(InternedString::new("target_family"), fam),
@ -629,7 +633,11 @@ pub fn default_configuration(sess: &Session) -> ast::CrateConfig {
mk(InternedString::new("target_endian"), intern(end)), mk(InternedString::new("target_endian"), intern(end)),
mk(InternedString::new("target_pointer_width"), mk(InternedString::new("target_pointer_width"),
intern(wordsz)) intern(wordsz))
); ];
if sess.opts.debug_assertions {
ret.push(attr::mk_word_item(InternedString::new("debug_assertions")));
}
return ret;
} }
pub fn append_configuration(cfg: &mut ast::CrateConfig, pub fn append_configuration(cfg: &mut ast::CrateConfig,
@ -923,6 +931,7 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
} }
} }
}; };
let debug_assertions = cg.debug_assertions.unwrap_or(opt_level == No);
let gc = debugging_opts.gc; let gc = debugging_opts.gc;
let debuginfo = if matches.opt_present("g") { let debuginfo = if matches.opt_present("g") {
if cg.debuginfo.is_some() { if cg.debuginfo.is_some() {
@ -1064,6 +1073,7 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
alt_std_name: None, alt_std_name: None,
libs: libs, libs: libs,
unstable_features: get_unstable_features_setting(), unstable_features: get_unstable_features_setting(),
debug_assertions: debug_assertions,
} }
} }

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@ -3089,7 +3089,7 @@ pub fn trans_crate<'tcx>(analysis: ty::CrateAnalysis<'tcx>)
let check_overflow = if let Some(v) = tcx.sess.opts.debugging_opts.force_overflow_checks { let check_overflow = if let Some(v) = tcx.sess.opts.debugging_opts.force_overflow_checks {
v v
} else { } else {
!attr::contains_name(&krate.config, "ndebug") tcx.sess.opts.debug_assertions
}; };
// Before we touch LLVM, make sure that multithreading is enabled. // Before we touch LLVM, make sure that multithreading is enabled.

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@ -9,6 +9,7 @@
// except according to those terms. // except according to those terms.
// error-pattern:thread '<main>' panicked at 'arithmetic operation overflowed' // error-pattern:thread '<main>' panicked at 'arithmetic operation overflowed'
// compile-flags: -C debug-assertions
// (Work around constant-evaluation) // (Work around constant-evaluation)
fn value() -> u8 { 200 } fn value() -> u8 { 200 }

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@ -9,6 +9,7 @@
// except according to those terms. // except according to those terms.
// error-pattern:thread '<main>' panicked at 'arithmetic operation overflowed' // error-pattern:thread '<main>' panicked at 'arithmetic operation overflowed'
// compile-flags: -C debug-assertions
// (Work around constant-evaluation) // (Work around constant-evaluation)
fn value() -> u8 { 200 } fn value() -> u8 { 200 }

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@ -9,6 +9,7 @@
// except according to those terms. // except according to those terms.
// error-pattern:thread '<main>' panicked at 'arithmetic operation overflowed' // error-pattern:thread '<main>' panicked at 'arithmetic operation overflowed'
// compile-flags: -C debug-assertions
// (Work around constant-evaluation) // (Work around constant-evaluation)
fn value() -> u8 { 42 } fn value() -> u8 { 42 }

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@ -0,0 +1,21 @@
-include ../tools.mk
all:
$(RUSTC) debug.rs -C debug-assertions=no
$(call RUN,debug) good
$(RUSTC) debug.rs -C opt-level=0
$(call RUN,debug) bad
$(RUSTC) debug.rs -C opt-level=1
$(call RUN,debug) good
$(RUSTC) debug.rs -C opt-level=2
$(call RUN,debug) good
$(RUSTC) debug.rs -C opt-level=3
$(call RUN,debug) good
$(RUSTC) debug.rs -O
$(call RUN,debug) good
$(RUSTC) debug.rs
$(call RUN,debug) bad
$(RUSTC) debug.rs -C debug-assertions=yes -O
$(call RUN,debug) bad
$(RUSTC) debug.rs -C debug-assertions=yes -C opt-level=1
$(call RUN,debug) bad

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@ -0,0 +1,42 @@
// Copyright 2015 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.
#![deny(warnings)]
use std::env;
use std::thread;
fn main() {
let should_fail = env::args().nth(1) == Some("bad".to_string());
assert_eq!(thread::spawn(debug_assert_eq).join().is_err(), should_fail);
assert_eq!(thread::spawn(debug_assert).join().is_err(), should_fail);
assert_eq!(thread::spawn(overflow).join().is_err(), should_fail);
}
fn debug_assert_eq() {
let mut hit1 = false;
let mut hit2 = false;
debug_assert_eq!({ hit1 = true; 1 }, { hit2 = true; 2 });
assert!(!hit1);
assert!(!hit2);
}
fn debug_assert() {
let mut hit = false;
debug_assert!({ hit = true; false });
assert!(!hit);
}
fn overflow() {
fn add(a: u8, b: u8) -> u8 { a + b }
add(200u8, 200u8);
}

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@ -8,7 +8,7 @@
// option. This file may not be copied, modified, or distributed // option. This file may not be copied, modified, or distributed
// except according to those terms. // except according to those terms.
// compile-flags: --cfg ndebug // compile-flags: -C debug-assertions=no
// exec-env:RUST_LOG=conditional-debug-macro-off=4 // exec-env:RUST_LOG=conditional-debug-macro-off=4
#[macro_use] #[macro_use]

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@ -8,7 +8,7 @@
// option. This file may not be copied, modified, or distributed // option. This file may not be copied, modified, or distributed
// except according to those terms. // except according to those terms.
// compile-flags:--cfg ndebug // compile-flags:-C debug-assertions=no
// exec-env:RUST_LOG=logging-enabled-debug=debug // exec-env:RUST_LOG=logging-enabled-debug=debug
#[macro_use] #[macro_use]

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@ -10,6 +10,7 @@
// ignore-windows // ignore-windows
// exec-env:RUST_LOG=debug // exec-env:RUST_LOG=debug
// compile-flags:-C debug-assertions=y
#[macro_use] #[macro_use]
extern crate log; extern crate log;