From 11c0e58c7489df3f71c3aebe04ad6d1b6a9f6262 Mon Sep 17 00:00:00 2001 From: Gary Guo Date: Tue, 14 Sep 2021 19:14:37 +0100 Subject: [PATCH] Allow `panic!("{}", computed_str)` in const fn. --- .../src/const_eval/machine.rs | 9 ++- .../src/transform/check_consts/check.rs | 13 +++++ .../src/transform/check_consts/mod.rs | 1 + compiler/rustc_hir/src/lang_items.rs | 1 + compiler/rustc_span/src/symbol.rs | 1 + library/core/src/panic.rs | 9 +++ library/core/src/panicking.rs | 7 +++ library/std/src/lib.rs | 1 + library/std/src/panic.rs | 6 +- library/std/src/rt.rs | 1 + src/test/ui/consts/const-eval/const_panic.rs | 8 ++- .../ui/consts/const-eval/const_panic.stderr | 38 ++++++++---- .../ui/consts/const-eval/const_panic_2021.rs | 16 +++-- .../consts/const-eval/const_panic_2021.stderr | 58 ++++++++++++------- 14 files changed, 129 insertions(+), 40 deletions(-) diff --git a/compiler/rustc_const_eval/src/const_eval/machine.rs b/compiler/rustc_const_eval/src/const_eval/machine.rs index 8a90686b9003f..ae20f6f97b212 100644 --- a/compiler/rustc_const_eval/src/const_eval/machine.rs +++ b/compiler/rustc_const_eval/src/const_eval/machine.rs @@ -36,12 +36,17 @@ impl<'mir, 'tcx> InterpCx<'mir, 'tcx, CompileTimeInterpreter<'mir, 'tcx>> { let def_id = instance.def_id(); if Some(def_id) == self.tcx.lang_items().panic_fn() || Some(def_id) == self.tcx.lang_items().panic_str() + || Some(def_id) == self.tcx.lang_items().panic_display() || Some(def_id) == self.tcx.lang_items().begin_panic_fn() { - // &str + // &str or &&str assert!(args.len() == 1); - let msg_place = self.deref_operand(&args[0])?; + let mut msg_place = self.deref_operand(&args[0])?; + while msg_place.layout.ty.is_ref() { + msg_place = self.deref_operand(&msg_place.into())?; + } + let msg = Symbol::intern(self.read_str(&msg_place)?); let span = self.find_closest_untracked_caller_location(); let (file, line, col) = self.location_triple_for_span(span); diff --git a/compiler/rustc_const_eval/src/transform/check_consts/check.rs b/compiler/rustc_const_eval/src/transform/check_consts/check.rs index 02b317b898106..038041cdbfbd9 100644 --- a/compiler/rustc_const_eval/src/transform/check_consts/check.rs +++ b/compiler/rustc_const_eval/src/transform/check_consts/check.rs @@ -888,6 +888,10 @@ impl Visitor<'tcx> for Checker<'mir, 'tcx> { if is_lang_panic_fn(tcx, callee) { self.check_op(ops::Panic); + // `begin_panic` and `panic_display` are generic functions that accept + // types other than str. Check to enforce that only str can be used in + // const-eval. + // const-eval of the `begin_panic` fn assumes the argument is `&str` if Some(callee) == tcx.lang_items().begin_panic_fn() { match args[0].ty(&self.ccx.body.local_decls, tcx).kind() { @@ -896,6 +900,15 @@ impl Visitor<'tcx> for Checker<'mir, 'tcx> { } } + // const-eval of the `panic_display` fn assumes the argument is `&&str` + if Some(callee) == tcx.lang_items().panic_display() { + match args[0].ty(&self.ccx.body.local_decls, tcx).kind() { + ty::Ref(_, ty, _) if matches!(ty.kind(), ty::Ref(_, ty, _) if ty.is_str()) => + {} + _ => self.check_op(ops::PanicNonStr), + } + } + return; } diff --git a/compiler/rustc_const_eval/src/transform/check_consts/mod.rs b/compiler/rustc_const_eval/src/transform/check_consts/mod.rs index a5cb0f4e14b17..d1fd3ceaa589a 100644 --- a/compiler/rustc_const_eval/src/transform/check_consts/mod.rs +++ b/compiler/rustc_const_eval/src/transform/check_consts/mod.rs @@ -79,6 +79,7 @@ pub fn is_lang_panic_fn(tcx: TyCtxt<'tcx>, def_id: DefId) -> bool { // Keep in sync with what that function handles! Some(def_id) == tcx.lang_items().panic_fn() || Some(def_id) == tcx.lang_items().panic_str() + || Some(def_id) == tcx.lang_items().panic_display() || Some(def_id) == tcx.lang_items().begin_panic_fn() || Some(def_id) == tcx.lang_items().panic_fmt() || Some(def_id) == tcx.lang_items().begin_panic_fmt() diff --git a/compiler/rustc_hir/src/lang_items.rs b/compiler/rustc_hir/src/lang_items.rs index b85ed0cb4bbe5..d69a247054026 100644 --- a/compiler/rustc_hir/src/lang_items.rs +++ b/compiler/rustc_hir/src/lang_items.rs @@ -283,6 +283,7 @@ language_item_table! { // a weak lang item, but do not have it defined. Panic, sym::panic, panic_fn, Target::Fn, GenericRequirement::None; PanicFmt, sym::panic_fmt, panic_fmt, Target::Fn, GenericRequirement::None; + PanicDisplay, sym::panic_display, panic_display, Target::Fn, GenericRequirement::None; PanicStr, sym::panic_str, panic_str, Target::Fn, GenericRequirement::None; ConstPanicFmt, sym::const_panic_fmt, const_panic_fmt, Target::Fn, GenericRequirement::None; PanicBoundsCheck, sym::panic_bounds_check, panic_bounds_check_fn, Target::Fn, GenericRequirement::None; diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs index c816d06045681..fb6fdcf28def8 100644 --- a/compiler/rustc_span/src/symbol.rs +++ b/compiler/rustc_span/src/symbol.rs @@ -923,6 +923,7 @@ symbols! { panic_2021, panic_abort, panic_bounds_check, + panic_display, panic_fmt, panic_handler, panic_impl, diff --git a/library/core/src/panic.rs b/library/core/src/panic.rs index 463bec37265d5..7a8b04d6f3c13 100644 --- a/library/core/src/panic.rs +++ b/library/core/src/panic.rs @@ -27,9 +27,14 @@ pub macro panic_2015 { ($msg:literal $(,)?) => ( $crate::panicking::panic($msg) ), + // Use `panic_str` instead of `panic_display::<&str>` for non_fmt_panic lint. ($msg:expr $(,)?) => ( $crate::panicking::panic_str($msg) ), + // Special-case the single-argument case for const_panic. + ("{}", $arg:expr $(,)?) => ( + $crate::panicking::panic_display(&$arg) + ), ($fmt:expr, $($arg:tt)+) => ( $crate::panicking::panic_fmt($crate::const_format_args!($fmt, $($arg)+)) ), @@ -44,6 +49,10 @@ pub macro panic_2021 { () => ( $crate::panicking::panic("explicit panic") ), + // Special-case the single-argument case for const_panic. + ("{}", $arg:expr $(,)?) => ( + $crate::panicking::panic_display(&$arg) + ), ($($t:tt)+) => ( $crate::panicking::panic_fmt($crate::const_format_args!($($t)+)) ), diff --git a/library/core/src/panicking.rs b/library/core/src/panicking.rs index 02f32675247c3..a6aa4bf43c865 100644 --- a/library/core/src/panicking.rs +++ b/library/core/src/panicking.rs @@ -60,6 +60,13 @@ pub fn panic_str(expr: &str) -> ! { panic_fmt(format_args!("{}", expr)); } +#[inline] +#[track_caller] +#[cfg_attr(not(bootstrap), lang = "panic_display")] // needed for const-evaluated panics +pub fn panic_display(x: &T) -> ! { + panic_fmt(format_args!("{}", *x)); +} + #[cold] #[cfg_attr(not(feature = "panic_immediate_abort"), inline(never))] #[track_caller] diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs index 83c6ba0e6ea45..559d2672a0da3 100644 --- a/library/std/src/lib.rs +++ b/library/std/src/lib.rs @@ -258,6 +258,7 @@ #![feature(const_trait_impl)] #![feature(container_error_extra)] #![feature(core_intrinsics)] +#![feature(core_panic)] #![feature(custom_test_frameworks)] #![feature(decl_macro)] #![feature(doc_cfg)] diff --git a/library/std/src/panic.rs b/library/std/src/panic.rs index c1c039584979d..21e9669c11079 100644 --- a/library/std/src/panic.rs +++ b/library/std/src/panic.rs @@ -10,7 +10,7 @@ use crate::thread::Result; #[doc(hidden)] #[unstable(feature = "edition_panic", issue = "none", reason = "use panic!() instead")] -#[allow_internal_unstable(libstd_sys_internals, const_format_args)] +#[allow_internal_unstable(libstd_sys_internals, const_format_args, core_panic)] #[cfg_attr(not(test), rustc_diagnostic_item = "std_panic_2015_macro")] #[rustc_macro_transparency = "semitransparent"] pub macro panic_2015 { @@ -20,6 +20,10 @@ pub macro panic_2015 { ($msg:expr $(,)?) => ({ $crate::rt::begin_panic($msg) }), + // Special-case the single-argument case for const_panic. + ("{}", $arg:expr $(,)?) => ({ + $crate::rt::panic_display(&$arg) + }), ($fmt:expr, $($arg:tt)+) => ({ $crate::rt::begin_panic_fmt(&$crate::const_format_args!($fmt, $($arg)+)) }), diff --git a/library/std/src/rt.rs b/library/std/src/rt.rs index 72e6c23ee4990..b4f2adf938b56 100644 --- a/library/std/src/rt.rs +++ b/library/std/src/rt.rs @@ -16,6 +16,7 @@ // Re-export some of our utilities which are expected by other crates. pub use crate::panicking::{begin_panic, begin_panic_fmt, panic_count}; +pub use core::panicking::panic_display; // To reduce the generated code of the new `lang_start`, this function is doing // the real work. diff --git a/src/test/ui/consts/const-eval/const_panic.rs b/src/test/ui/consts/const-eval/const_panic.rs index e4455d86a1440..100faded079d5 100644 --- a/src/test/ui/consts/const-eval/const_panic.rs +++ b/src/test/ui/consts/const-eval/const_panic.rs @@ -15,10 +15,13 @@ const Y: () = std::unreachable!(); const X: () = std::unimplemented!(); //~^ ERROR evaluation of constant value failed -// + const W: () = std::panic!(MSG); //~^ ERROR evaluation of constant value failed +const W2: () = std::panic!("{}", MSG); +//~^ ERROR evaluation of constant value failed + const Z_CORE: () = core::panic!("cheese"); //~^ ERROR evaluation of constant value failed @@ -33,3 +36,6 @@ const X_CORE: () = core::unimplemented!(); const W_CORE: () = core::panic!(MSG); //~^ ERROR evaluation of constant value failed + +const W2_CORE: () = core::panic!("{}", MSG); +//~^ ERROR evaluation of constant value failed diff --git a/src/test/ui/consts/const-eval/const_panic.stderr b/src/test/ui/consts/const-eval/const_panic.stderr index c0c749ede5612..e98e4a506c0d6 100644 --- a/src/test/ui/consts/const-eval/const_panic.stderr +++ b/src/test/ui/consts/const-eval/const_panic.stderr @@ -39,45 +39,61 @@ LL | const W: () = std::panic!(MSG); = note: this error originates in the macro `$crate::panic::panic_2015` (in Nightly builds, run with -Z macro-backtrace for more info) error[E0080]: evaluation of constant value failed - --> $DIR/const_panic.rs:22:20 + --> $DIR/const_panic.rs:22:16 + | +LL | const W2: () = std::panic!("{}", MSG); + | ^^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'hello', $DIR/const_panic.rs:22:16 + | + = note: this error originates in the macro `$crate::panic::panic_2015` (in Nightly builds, run with -Z macro-backtrace for more info) + +error[E0080]: evaluation of constant value failed + --> $DIR/const_panic.rs:25:20 | LL | const Z_CORE: () = core::panic!("cheese"); - | ^^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'cheese', $DIR/const_panic.rs:22:20 + | ^^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'cheese', $DIR/const_panic.rs:25:20 | = note: this error originates in the macro `$crate::panic::panic_2015` (in Nightly builds, run with -Z macro-backtrace for more info) error[E0080]: evaluation of constant value failed - --> $DIR/const_panic.rs:25:21 + --> $DIR/const_panic.rs:28:21 | LL | const Z2_CORE: () = core::panic!(); - | ^^^^^^^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/const_panic.rs:25:21 + | ^^^^^^^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/const_panic.rs:28:21 | = note: this error originates in the macro `$crate::panic::panic_2015` (in Nightly builds, run with -Z macro-backtrace for more info) error[E0080]: evaluation of constant value failed - --> $DIR/const_panic.rs:28:20 + --> $DIR/const_panic.rs:31:20 | LL | const Y_CORE: () = core::unreachable!(); - | ^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'internal error: entered unreachable code', $DIR/const_panic.rs:28:20 + | ^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'internal error: entered unreachable code', $DIR/const_panic.rs:31:20 | = note: this error originates in the macro `$crate::panic::panic_2015` (in Nightly builds, run with -Z macro-backtrace for more info) error[E0080]: evaluation of constant value failed - --> $DIR/const_panic.rs:31:20 + --> $DIR/const_panic.rs:34:20 | LL | const X_CORE: () = core::unimplemented!(); - | ^^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'not implemented', $DIR/const_panic.rs:31:20 + | ^^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'not implemented', $DIR/const_panic.rs:34:20 | = note: this error originates in the macro `$crate::panic::panic_2015` (in Nightly builds, run with -Z macro-backtrace for more info) error[E0080]: evaluation of constant value failed - --> $DIR/const_panic.rs:34:20 + --> $DIR/const_panic.rs:37:20 | LL | const W_CORE: () = core::panic!(MSG); - | ^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'hello', $DIR/const_panic.rs:34:20 + | ^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'hello', $DIR/const_panic.rs:37:20 + | + = note: this error originates in the macro `$crate::panic::panic_2015` (in Nightly builds, run with -Z macro-backtrace for more info) + +error[E0080]: evaluation of constant value failed + --> $DIR/const_panic.rs:40:21 + | +LL | const W2_CORE: () = core::panic!("{}", MSG); + | ^^^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'hello', $DIR/const_panic.rs:40:21 | = note: this error originates in the macro `$crate::panic::panic_2015` (in Nightly builds, run with -Z macro-backtrace for more info) -error: aborting due to 10 previous errors +error: aborting due to 12 previous errors For more information about this error, try `rustc --explain E0080`. diff --git a/src/test/ui/consts/const-eval/const_panic_2021.rs b/src/test/ui/consts/const-eval/const_panic_2021.rs index daef34cd6a306..9b8652a776e61 100644 --- a/src/test/ui/consts/const-eval/const_panic_2021.rs +++ b/src/test/ui/consts/const-eval/const_panic_2021.rs @@ -2,6 +2,8 @@ #![feature(const_panic)] #![crate_type = "lib"] +const MSG: &str = "hello"; + const A: () = std::panic!("blåhaj"); //~^ ERROR evaluation of constant value failed @@ -14,14 +16,20 @@ const C: () = std::unreachable!(); const D: () = std::unimplemented!(); //~^ ERROR evaluation of constant value failed -const E: () = core::panic!("shark"); +const E: () = std::panic!("{}", MSG); +//~^ ERROR evaluation of constant value failed + +const A_CORE: () = core::panic!("shark"); +//~^ ERROR evaluation of constant value failed + +const B_CORE: () = core::panic!(); //~^ ERROR evaluation of constant value failed -const F: () = core::panic!(); +const C_CORE: () = core::unreachable!(); //~^ ERROR evaluation of constant value failed -const G: () = core::unreachable!(); +const D_CORE: () = core::unimplemented!(); //~^ ERROR evaluation of constant value failed -const H: () = core::unimplemented!(); +const E_CORE: () = core::panic!("{}", MSG); //~^ ERROR evaluation of constant value failed diff --git a/src/test/ui/consts/const-eval/const_panic_2021.stderr b/src/test/ui/consts/const-eval/const_panic_2021.stderr index c1bdab3693d11..9eb241ae8e59d 100644 --- a/src/test/ui/consts/const-eval/const_panic_2021.stderr +++ b/src/test/ui/consts/const-eval/const_panic_2021.stderr @@ -1,67 +1,83 @@ error[E0080]: evaluation of constant value failed - --> $DIR/const_panic_2021.rs:5:15 + --> $DIR/const_panic_2021.rs:7:15 | LL | const A: () = std::panic!("blåhaj"); - | ^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'blåhaj', $DIR/const_panic_2021.rs:5:15 + | ^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'blåhaj', $DIR/const_panic_2021.rs:7:15 | = note: this error originates in the macro `$crate::panic::panic_2021` (in Nightly builds, run with -Z macro-backtrace for more info) error[E0080]: evaluation of constant value failed - --> $DIR/const_panic_2021.rs:8:15 + --> $DIR/const_panic_2021.rs:10:15 | LL | const B: () = std::panic!(); - | ^^^^^^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/const_panic_2021.rs:8:15 + | ^^^^^^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/const_panic_2021.rs:10:15 | = note: this error originates in the macro `$crate::panic::panic_2021` (in Nightly builds, run with -Z macro-backtrace for more info) error[E0080]: evaluation of constant value failed - --> $DIR/const_panic_2021.rs:11:15 + --> $DIR/const_panic_2021.rs:13:15 | LL | const C: () = std::unreachable!(); - | ^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'internal error: entered unreachable code', $DIR/const_panic_2021.rs:11:15 + | ^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'internal error: entered unreachable code', $DIR/const_panic_2021.rs:13:15 | = note: this error originates in the macro `$crate::panic::panic_2015` (in Nightly builds, run with -Z macro-backtrace for more info) error[E0080]: evaluation of constant value failed - --> $DIR/const_panic_2021.rs:14:15 + --> $DIR/const_panic_2021.rs:16:15 | LL | const D: () = std::unimplemented!(); - | ^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'not implemented', $DIR/const_panic_2021.rs:14:15 + | ^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'not implemented', $DIR/const_panic_2021.rs:16:15 | = note: this error originates in the macro `$crate::panic::panic_2015` (in Nightly builds, run with -Z macro-backtrace for more info) error[E0080]: evaluation of constant value failed - --> $DIR/const_panic_2021.rs:17:15 + --> $DIR/const_panic_2021.rs:19:15 | -LL | const E: () = core::panic!("shark"); - | ^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'shark', $DIR/const_panic_2021.rs:17:15 +LL | const E: () = std::panic!("{}", MSG); + | ^^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'hello', $DIR/const_panic_2021.rs:19:15 | = note: this error originates in the macro `$crate::panic::panic_2021` (in Nightly builds, run with -Z macro-backtrace for more info) error[E0080]: evaluation of constant value failed - --> $DIR/const_panic_2021.rs:20:15 + --> $DIR/const_panic_2021.rs:22:20 | -LL | const F: () = core::panic!(); - | ^^^^^^^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/const_panic_2021.rs:20:15 +LL | const A_CORE: () = core::panic!("shark"); + | ^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'shark', $DIR/const_panic_2021.rs:22:20 | = note: this error originates in the macro `$crate::panic::panic_2021` (in Nightly builds, run with -Z macro-backtrace for more info) error[E0080]: evaluation of constant value failed - --> $DIR/const_panic_2021.rs:23:15 + --> $DIR/const_panic_2021.rs:25:20 | -LL | const G: () = core::unreachable!(); - | ^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'internal error: entered unreachable code', $DIR/const_panic_2021.rs:23:15 +LL | const B_CORE: () = core::panic!(); + | ^^^^^^^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/const_panic_2021.rs:25:20 + | + = note: this error originates in the macro `$crate::panic::panic_2021` (in Nightly builds, run with -Z macro-backtrace for more info) + +error[E0080]: evaluation of constant value failed + --> $DIR/const_panic_2021.rs:28:20 + | +LL | const C_CORE: () = core::unreachable!(); + | ^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'internal error: entered unreachable code', $DIR/const_panic_2021.rs:28:20 | = note: this error originates in the macro `$crate::panic::panic_2015` (in Nightly builds, run with -Z macro-backtrace for more info) error[E0080]: evaluation of constant value failed - --> $DIR/const_panic_2021.rs:26:15 + --> $DIR/const_panic_2021.rs:31:20 | -LL | const H: () = core::unimplemented!(); - | ^^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'not implemented', $DIR/const_panic_2021.rs:26:15 +LL | const D_CORE: () = core::unimplemented!(); + | ^^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'not implemented', $DIR/const_panic_2021.rs:31:20 | = note: this error originates in the macro `$crate::panic::panic_2015` (in Nightly builds, run with -Z macro-backtrace for more info) -error: aborting due to 8 previous errors +error[E0080]: evaluation of constant value failed + --> $DIR/const_panic_2021.rs:34:20 + | +LL | const E_CORE: () = core::panic!("{}", MSG); + | ^^^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'hello', $DIR/const_panic_2021.rs:34:20 + | + = note: this error originates in the macro `$crate::panic::panic_2021` (in Nightly builds, run with -Z macro-backtrace for more info) + +error: aborting due to 10 previous errors For more information about this error, try `rustc --explain E0080`.