diff options
Diffstat (limited to 'compiler/rustc_const_eval/src/const_eval')
| -rw-r--r-- | compiler/rustc_const_eval/src/const_eval/error.rs | 280 | ||||
| -rw-r--r-- | compiler/rustc_const_eval/src/const_eval/eval_queries.rs | 100 | ||||
| -rw-r--r-- | compiler/rustc_const_eval/src/const_eval/machine.rs | 119 | ||||
| -rw-r--r-- | compiler/rustc_const_eval/src/const_eval/mod.rs | 52 |
4 files changed, 295 insertions, 256 deletions
diff --git a/compiler/rustc_const_eval/src/const_eval/error.rs b/compiler/rustc_const_eval/src/const_eval/error.rs index c591ff75ab8..7890d878d08 100644 --- a/compiler/rustc_const_eval/src/const_eval/error.rs +++ b/compiler/rustc_const_eval/src/const_eval/error.rs @@ -1,17 +1,15 @@ -use std::error::Error; -use std::fmt; +use std::mem; -use rustc_errors::Diagnostic; +use rustc_errors::{DiagnosticArgValue, DiagnosticMessage, IntoDiagnostic, IntoDiagnosticArg}; use rustc_middle::mir::AssertKind; -use rustc_middle::query::TyCtxtAt; +use rustc_middle::ty::TyCtxt; use rustc_middle::ty::{layout::LayoutError, ConstInt}; -use rustc_span::{Span, Symbol}; +use rustc_span::source_map::Spanned; +use rustc_span::{ErrorGuaranteed, Span, Symbol}; use super::InterpCx; -use crate::interpret::{ - struct_error, ErrorHandled, FrameInfo, InterpError, InterpErrorInfo, Machine, MachineStopType, - UnsupportedOpInfo, -}; +use crate::errors::{self, FrameNote, ReportErrorExt}; +use crate::interpret::{ErrorHandled, InterpError, InterpErrorInfo, Machine, MachineStopType}; /// The CTFE machine has some custom error kinds. #[derive(Clone, Debug)] @@ -23,7 +21,35 @@ pub enum ConstEvalErrKind { Abort(String), } -impl MachineStopType for ConstEvalErrKind {} +impl MachineStopType for ConstEvalErrKind { + fn diagnostic_message(&self) -> DiagnosticMessage { + use crate::fluent_generated::*; + use ConstEvalErrKind::*; + match self { + ConstAccessesStatic => const_eval_const_accesses_static, + ModifiedGlobal => const_eval_modified_global, + Panic { .. } => const_eval_panic, + AssertFailure(x) => x.diagnostic_message(), + Abort(msg) => msg.to_string().into(), + } + } + fn add_args( + self: Box<Self>, + adder: &mut dyn FnMut(std::borrow::Cow<'static, str>, DiagnosticArgValue<'static>), + ) { + use ConstEvalErrKind::*; + match *self { + ConstAccessesStatic | ModifiedGlobal | Abort(_) => {} + AssertFailure(kind) => kind.add_args(adder), + Panic { msg, line, col, file } => { + adder("msg".into(), msg.into_diagnostic_arg()); + adder("file".into(), file.into_diagnostic_arg()); + adder("line".into(), line.into_diagnostic_arg()); + adder("col".into(), col.into_diagnostic_arg()); + } + } + } +} // The errors become `MachineStop` with plain strings when being raised. // `ConstEvalErr` (in `librustc_middle/mir/interpret/error.rs`) knows to @@ -34,151 +60,117 @@ impl<'tcx> Into<InterpErrorInfo<'tcx>> for ConstEvalErrKind { } } -impl fmt::Display for ConstEvalErrKind { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - use self::ConstEvalErrKind::*; - match self { - ConstAccessesStatic => write!(f, "constant accesses static"), - ModifiedGlobal => { - write!(f, "modifying a static's initial value from another static's initializer") - } - AssertFailure(msg) => write!(f, "{:?}", msg), - Panic { msg, line, col, file } => { - write!(f, "the evaluated program panicked at '{}', {}:{}:{}", msg, file, line, col) - } - Abort(msg) => write!(f, "{}", msg), - } - } -} - -impl Error for ConstEvalErrKind {} +pub fn get_span_and_frames<'tcx, 'mir, M: Machine<'mir, 'tcx>>( + ecx: &InterpCx<'mir, 'tcx, M>, +) -> (Span, Vec<errors::FrameNote>) +where + 'tcx: 'mir, +{ + let mut stacktrace = ecx.generate_stacktrace(); + // Filter out `requires_caller_location` frames. + stacktrace.retain(|frame| !frame.instance.def.requires_caller_location(*ecx.tcx)); + let span = stacktrace.first().map(|f| f.span).unwrap_or(ecx.tcx.span); -/// When const-evaluation errors, this type is constructed with the resulting information, -/// and then used to emit the error as a lint or hard error. -#[derive(Debug)] -pub(super) struct ConstEvalErr<'tcx> { - pub span: Span, - pub error: InterpError<'tcx>, - pub stacktrace: Vec<FrameInfo<'tcx>>, -} + let mut frames = Vec::new(); -impl<'tcx> ConstEvalErr<'tcx> { - /// Turn an interpreter error into something to report to the user. - /// As a side-effect, if RUSTC_CTFE_BACKTRACE is set, this prints the backtrace. - /// Should be called only if the error is actually going to be reported! - pub fn new<'mir, M: Machine<'mir, 'tcx>>( - ecx: &InterpCx<'mir, 'tcx, M>, - error: InterpErrorInfo<'tcx>, - span: Option<Span>, - ) -> ConstEvalErr<'tcx> - where - 'tcx: 'mir, - { - error.print_backtrace(); - let mut stacktrace = ecx.generate_stacktrace(); - // Filter out `requires_caller_location` frames. - stacktrace.retain(|frame| !frame.instance.def.requires_caller_location(*ecx.tcx)); - // If `span` is missing, use topmost remaining frame, or else the "root" span from `ecx.tcx`. - let span = span.or_else(|| stacktrace.first().map(|f| f.span)).unwrap_or(ecx.tcx.span); - ConstEvalErr { error: error.into_kind(), stacktrace, span } - } - - pub(super) fn report(&self, tcx: TyCtxtAt<'tcx>, message: &str) -> ErrorHandled { - self.report_decorated(tcx, message, |_| {}) - } - - #[instrument(level = "trace", skip(self, decorate))] - pub(super) fn decorate(&self, err: &mut Diagnostic, decorate: impl FnOnce(&mut Diagnostic)) { - trace!("reporting const eval failure at {:?}", self.span); - // Add some more context for select error types. - match self.error { - InterpError::Unsupported( - UnsupportedOpInfo::ReadPointerAsBytes - | UnsupportedOpInfo::PartialPointerOverwrite(_) - | UnsupportedOpInfo::PartialPointerCopy(_), - ) => { - err.help("this code performed an operation that depends on the underlying bytes representing a pointer"); - err.help("the absolute address of a pointer is not known at compile-time, so such operations are not supported"); + // Add notes to the backtrace. Don't print a single-line backtrace though. + if stacktrace.len() > 1 { + // Helper closure to print duplicated lines. + let mut add_frame = |mut frame: errors::FrameNote| { + frames.push(errors::FrameNote { times: 0, ..frame.clone() }); + // Don't print [... additional calls ...] if the number of lines is small + if frame.times < 3 { + let times = frame.times; + frame.times = 0; + frames.extend(std::iter::repeat(frame).take(times as usize)); + } else { + frames.push(frame); } - _ => {} - } - // Add spans for the stacktrace. Don't print a single-line backtrace though. - if self.stacktrace.len() > 1 { - // Helper closure to print duplicated lines. - let mut flush_last_line = |last_frame: Option<(String, _)>, times| { - if let Some((line, span)) = last_frame { - err.span_note(span, line.clone()); - // Don't print [... additional calls ...] if the number of lines is small - if times < 3 { - for _ in 0..times { - err.span_note(span, line.clone()); - } - } else { - err.span_note( - span, - format!("[... {} additional calls {} ...]", times, &line), - ); - } - } - }; + }; - let mut last_frame = None; - let mut times = 0; - for frame_info in &self.stacktrace { - let frame = (frame_info.to_string(), frame_info.span); - if last_frame.as_ref() == Some(&frame) { - times += 1; - } else { - flush_last_line(last_frame, times); + let mut last_frame: Option<errors::FrameNote> = None; + for frame_info in &stacktrace { + let frame = frame_info.as_note(*ecx.tcx); + match last_frame.as_mut() { + Some(last_frame) + if last_frame.span == frame.span + && last_frame.where_ == frame.where_ + && last_frame.instance == frame.instance => + { + last_frame.times += 1; + } + Some(last_frame) => { + add_frame(mem::replace(last_frame, frame)); + } + None => { last_frame = Some(frame); - times = 0; } } - flush_last_line(last_frame, times); } - // Let the caller attach any additional information it wants. - decorate(err); + if let Some(frame) = last_frame { + add_frame(frame); + } } - /// Create a diagnostic for this const eval error. - /// - /// Sets the message passed in via `message` and adds span labels with detailed error - /// information before handing control back to `decorate` to do any final annotations, - /// after which the diagnostic is emitted. - /// - /// If `lint_root.is_some()` report it as a lint, else report it as a hard error. - /// (Except that for some errors, we ignore all that -- see `must_error` below.) - #[instrument(skip(self, tcx, decorate), level = "debug")] - pub(super) fn report_decorated( - &self, - tcx: TyCtxtAt<'tcx>, - message: &str, - decorate: impl FnOnce(&mut Diagnostic), - ) -> ErrorHandled { - debug!("self.error: {:?}", self.error); - // Special handling for certain errors - match &self.error { - // Don't emit a new diagnostic for these errors - err_inval!(Layout(LayoutError::Unknown(_))) | err_inval!(TooGeneric) => { - ErrorHandled::TooGeneric - } - err_inval!(AlreadyReported(error_reported)) => ErrorHandled::Reported(*error_reported), - err_inval!(Layout(LayoutError::SizeOverflow(_))) => { - // We must *always* hard error on these, even if the caller wants just a lint. - // The `message` makes little sense here, this is a more serious error than the - // caller thinks anyway. - // See <https://github.com/rust-lang/rust/pull/63152>. - let mut err = struct_error(tcx, &self.error.to_string()); - self.decorate(&mut err, decorate); - ErrorHandled::Reported(err.emit().into()) - } - _ => { - // Report as hard error. - let mut err = struct_error(tcx, message); - err.span_label(self.span, self.error.to_string()); - self.decorate(&mut err, decorate); - ErrorHandled::Reported(err.emit().into()) + (span, frames) +} + +/// Create a diagnostic for a const eval error. +/// +/// This will use the `mk` function for creating the error which will get passed labels according to +/// the `InterpError` and the span and a stacktrace of current execution according to +/// `get_span_and_frames`. +pub(super) fn report<'tcx, C, F, E>( + tcx: TyCtxt<'tcx>, + error: InterpError<'tcx>, + span: Option<Span>, + get_span_and_frames: C, + mk: F, +) -> ErrorHandled +where + C: FnOnce() -> (Span, Vec<FrameNote>), + F: FnOnce(Span, Vec<FrameNote>) -> E, + E: IntoDiagnostic<'tcx, ErrorGuaranteed>, +{ + // Special handling for certain errors + match error { + // Don't emit a new diagnostic for these errors + err_inval!(Layout(LayoutError::Unknown(_))) | err_inval!(TooGeneric) => { + ErrorHandled::TooGeneric + } + err_inval!(AlreadyReported(error_reported)) => ErrorHandled::Reported(error_reported), + err_inval!(Layout(layout_error @ LayoutError::SizeOverflow(_))) => { + // We must *always* hard error on these, even if the caller wants just a lint. + // The `message` makes little sense here, this is a more serious error than the + // caller thinks anyway. + // See <https://github.com/rust-lang/rust/pull/63152>. + let (our_span, frames) = get_span_and_frames(); + let span = span.unwrap_or(our_span); + let mut err = + tcx.sess.create_err(Spanned { span, node: layout_error.into_diagnostic() }); + err.code(rustc_errors::error_code!(E0080)); + let Some((mut err, handler)) = err.into_diagnostic() else { + panic!("did not emit diag"); + }; + for frame in frames { + err.eager_subdiagnostic(handler, frame); } + + ErrorHandled::Reported(handler.emit_diagnostic(&mut err).unwrap().into()) + } + _ => { + // Report as hard error. + let (our_span, frames) = get_span_and_frames(); + let span = span.unwrap_or(our_span); + let err = mk(span, frames); + let mut err = tcx.sess.create_err(err); + + let msg = error.diagnostic_message(); + error.add_args(&tcx.sess.parse_sess.span_diagnostic, &mut err); + + // Use *our* span to label the interp error + err.span_label(our_span, msg); + ErrorHandled::Reported(err.emit().into()) } } } diff --git a/compiler/rustc_const_eval/src/const_eval/eval_queries.rs b/compiler/rustc_const_eval/src/const_eval/eval_queries.rs index 046d2052968..8b8e8ff58e9 100644 --- a/compiler/rustc_const_eval/src/const_eval/eval_queries.rs +++ b/compiler/rustc_const_eval/src/const_eval/eval_queries.rs @@ -1,12 +1,12 @@ use crate::const_eval::CheckAlignment; -use std::borrow::Cow; +use crate::errors::ConstEvalError; use either::{Left, Right}; use rustc_hir::def::DefKind; use rustc_middle::mir; -use rustc_middle::mir::interpret::ErrorHandled; -use rustc_middle::mir::pretty::display_allocation; +use rustc_middle::mir::interpret::{ErrorHandled, InterpErrorInfo}; +use rustc_middle::mir::pretty::write_allocation_bytes; use rustc_middle::traits::Reveal; use rustc_middle::ty::layout::LayoutOf; use rustc_middle::ty::print::with_no_trimmed_paths; @@ -14,7 +14,8 @@ use rustc_middle::ty::{self, TyCtxt}; use rustc_span::source_map::Span; use rustc_target::abi::{self, Abi}; -use super::{CompileTimeEvalContext, CompileTimeInterpreter, ConstEvalErr}; +use super::{CompileTimeEvalContext, CompileTimeInterpreter}; +use crate::errors; use crate::interpret::eval_nullary_intrinsic; use crate::interpret::{ intern_const_alloc_recursive, Allocation, ConstAlloc, ConstValue, CtfeValidationMode, GlobalId, @@ -22,10 +23,6 @@ use crate::interpret::{ RefTracking, StackPopCleanup, }; -const NOTE_ON_UNDEFINED_BEHAVIOR_ERROR: &str = "The rules on what exactly is undefined behavior aren't clear, \ - so this check might be overzealous. Please open an issue on the rustc \ - repository if you believe it should not be considered undefined behavior."; - // Returns a pointer to where the result lives fn eval_body_using_ecx<'mir, 'tcx>( ecx: &mut CompileTimeEvalContext<'mir, 'tcx>, @@ -103,7 +100,7 @@ pub(super) fn mk_eval_cx<'mir, 'tcx>( tcx, root_span, param_env, - CompileTimeInterpreter::new(tcx.const_eval_limit(), can_access_statics, CheckAlignment::No), + CompileTimeInterpreter::new(can_access_statics, CheckAlignment::No), ) } @@ -253,8 +250,14 @@ pub fn eval_to_const_value_raw_provider<'tcx>( }; return eval_nullary_intrinsic(tcx, key.param_env, def_id, substs).map_err(|error| { let span = tcx.def_span(def_id); - let error = ConstEvalErr { error: error.into_kind(), stacktrace: vec![], span }; - error.report(tcx.at(span), "could not evaluate nullary intrinsic") + + super::report( + tcx, + error.into_kind(), + Some(span), + || (span, vec![]), + |span, _| errors::NullaryIntrinsicError { span }, + ) }); } @@ -306,7 +309,6 @@ pub fn eval_to_allocation_raw_provider<'tcx>( // Statics (and promoteds inside statics) may access other statics, because unlike consts // they do not have to behave "as if" they were evaluated at runtime. CompileTimeInterpreter::new( - tcx.const_eval_limit(), /*can_access_statics:*/ is_static, if tcx.sess.opts.unstable_opts.extra_const_ub_checks { CheckAlignment::Error @@ -319,9 +321,11 @@ pub fn eval_to_allocation_raw_provider<'tcx>( let res = ecx.load_mir(cid.instance.def, cid.promoted); match res.and_then(|body| eval_body_using_ecx(&mut ecx, cid, &body)) { Err(error) => { - let err = ConstEvalErr::new(&ecx, error, None); - let msg = if is_static { - Cow::from("could not evaluate static initializer") + let (error, backtrace) = error.into_parts(); + backtrace.print_backtrace(); + + let (kind, instance) = if is_static { + ("static", String::new()) } else { // If the current item has generics, we'd like to enrich the message with the // instance and its substs: to show the actual compile-time values, in addition to @@ -329,19 +333,29 @@ pub fn eval_to_allocation_raw_provider<'tcx>( let instance = &key.value.instance; if !instance.substs.is_empty() { let instance = with_no_trimmed_paths!(instance.to_string()); - let msg = format!("evaluation of `{}` failed", instance); - Cow::from(msg) + ("const_with_path", instance) } else { - Cow::from("evaluation of constant value failed") + ("const", String::new()) } }; - Err(err.report(ecx.tcx.at(err.span), &msg)) + Err(super::report( + *ecx.tcx, + error, + None, + || super::get_span_and_frames(&ecx), + |span, frames| ConstEvalError { + span, + error_kind: kind, + instance, + frame_notes: frames, + }, + )) } Ok(mplace) => { // Since evaluation had no errors, validate the resulting constant. // This is a separate `try` block to provide more targeted error reporting. - let validation = try { + let validation: Result<_, InterpErrorInfo<'_>> = try { let mut ref_tracking = RefTracking::new(mplace); let mut inner = false; while let Some((mplace, path)) = ref_tracking.todo.pop() { @@ -358,23 +372,37 @@ pub fn eval_to_allocation_raw_provider<'tcx>( } }; let alloc_id = mplace.ptr.provenance.unwrap(); + + // Validation failed, report an error. This is always a hard error. if let Err(error) = validation { - // Validation failed, report an error. This is always a hard error. - let err = ConstEvalErr::new(&ecx, error, None); - Err(err.report_decorated( - ecx.tcx, - "it is undefined behavior to use this value", - |diag| { - if matches!(err.error, InterpError::UndefinedBehavior(_)) { - diag.note(NOTE_ON_UNDEFINED_BEHAVIOR_ERROR); - } - diag.note(format!( - "the raw bytes of the constant ({}", - display_allocation( - *ecx.tcx, - ecx.tcx.global_alloc(alloc_id).unwrap_memory().inner() - ) - )); + let (error, backtrace) = error.into_parts(); + backtrace.print_backtrace(); + + let ub_note = matches!(error, InterpError::UndefinedBehavior(_)).then(|| {}); + + let alloc = ecx.tcx.global_alloc(alloc_id).unwrap_memory().inner(); + let mut bytes = String::new(); + if alloc.size() != abi::Size::ZERO { + bytes = "\n".into(); + // FIXME(translation) there might be pieces that are translatable. + write_allocation_bytes(*ecx.tcx, alloc, &mut bytes, " ").unwrap(); + } + let raw_bytes = errors::RawBytesNote { + size: alloc.size().bytes(), + align: alloc.align.bytes(), + bytes, + }; + + Err(super::report( + *ecx.tcx, + error, + None, + || super::get_span_and_frames(&ecx), + move |span, frames| errors::UndefinedBehavior { + span, + ub_note, + frames, + raw_bytes, }, )) } else { diff --git a/compiler/rustc_const_eval/src/const_eval/machine.rs b/compiler/rustc_const_eval/src/const_eval/machine.rs index 58b5755af07..7391f567040 100644 --- a/compiler/rustc_const_eval/src/const_eval/machine.rs +++ b/compiler/rustc_const_eval/src/const_eval/machine.rs @@ -16,25 +16,37 @@ use std::fmt; use rustc_ast::Mutability; use rustc_hir::def_id::DefId; use rustc_middle::mir::AssertMessage; -use rustc_session::Limit; use rustc_span::symbol::{sym, Symbol}; use rustc_target::abi::{Align, Size}; use rustc_target::spec::abi::Abi as CallAbi; +use crate::errors::{LongRunning, LongRunningWarn}; use crate::interpret::{ self, compile_time_machine, AllocId, ConstAllocation, FnVal, Frame, ImmTy, InterpCx, InterpResult, OpTy, PlaceTy, Pointer, Scalar, }; +use crate::{errors, fluent_generated as fluent}; use super::error::*; +/// When hitting this many interpreted terminators we emit a deny by default lint +/// that notfies the user that their constant takes a long time to evaluate. If that's +/// what they intended, they can just allow the lint. +const LINT_TERMINATOR_LIMIT: usize = 2_000_000; +/// The limit used by `-Z tiny-const-eval-limit`. This smaller limit is useful for internal +/// tests not needing to run 30s or more to show some behaviour. +const TINY_LINT_TERMINATOR_LIMIT: usize = 20; +/// After this many interpreted terminators, we start emitting progress indicators at every +/// power of two of interpreted terminators. +const PROGRESS_INDICATOR_START: usize = 4_000_000; + /// Extra machine state for CTFE, and the Machine instance pub struct CompileTimeInterpreter<'mir, 'tcx> { - /// For now, the number of terminators that can be evaluated before we throw a resource - /// exhaustion error. + /// The number of terminators that have been evaluated. /// - /// Setting this to `0` disables the limit and allows the interpreter to run forever. - pub(super) steps_remaining: usize, + /// This is used to produce lints informing the user that the compiler is not stuck. + /// Set to `usize::MAX` to never report anything. + pub(super) num_evaluated_steps: usize, /// The virtual call stack. pub(super) stack: Vec<Frame<'mir, 'tcx, AllocId, ()>>, @@ -72,13 +84,9 @@ impl CheckAlignment { } impl<'mir, 'tcx> CompileTimeInterpreter<'mir, 'tcx> { - pub(crate) fn new( - const_eval_limit: Limit, - can_access_statics: bool, - check_alignment: CheckAlignment, - ) -> Self { + pub(crate) fn new(can_access_statics: bool, check_alignment: CheckAlignment) -> Self { CompileTimeInterpreter { - steps_remaining: const_eval_limit.0, + num_evaluated_steps: 0, stack: Vec::new(), can_access_statics, check_alignment, @@ -247,7 +255,10 @@ impl<'mir, 'tcx: 'mir> CompileTimeEvalContext<'mir, 'tcx> { let target_align = self.read_scalar(&args[1])?.to_target_usize(self)?; if !target_align.is_power_of_two() { - throw_ub_format!("`align_offset` called with non-power-of-two align: {}", target_align); + throw_ub_custom!( + fluent::const_eval_align_offset_invalid_align, + target_align = target_align, + ); } match self.ptr_try_get_alloc_id(ptr) { @@ -353,15 +364,18 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir, "`alignment_check_failed` called when no alignment check requested" ), CheckAlignment::FutureIncompat => { - let err = ConstEvalErr::new(ecx, err, None); - ecx.tcx.struct_span_lint_hir( + let (_, backtrace) = err.into_parts(); + backtrace.print_backtrace(); + let (span, frames) = super::get_span_and_frames(&ecx); + + ecx.tcx.emit_spanned_lint( INVALID_ALIGNMENT, ecx.stack().iter().find_map(|frame| frame.lint_root()).unwrap_or(CRATE_HIR_ID), - err.span, - err.error.to_string(), - |db| { - err.decorate(db, |_| {}); - db + span, + errors::AlignmentCheckFailed { + has: has.bytes(), + required: required.bytes(), + frames, }, ); Ok(()) @@ -475,7 +489,12 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir, let align = match Align::from_bytes(align) { Ok(a) => a, - Err(err) => throw_ub_format!("align has to be a power of 2, {}", err), + Err(err) => throw_ub_custom!( + fluent::const_eval_invalid_align_details, + name = "const_allocate", + err_kind = err.diag_ident(), + align = err.align() + ), }; let ptr = ecx.allocate_ptr( @@ -493,7 +512,12 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir, let size = Size::from_bytes(size); let align = match Align::from_bytes(align) { Ok(a) => a, - Err(err) => throw_ub_format!("align has to be a power of 2, {}", err), + Err(err) => throw_ub_custom!( + fluent::const_eval_invalid_align_details, + name = "const_deallocate", + err_kind = err.diag_ident(), + align = err.align() + ), }; // If an allocation is created in an another const, @@ -569,13 +593,54 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir, fn increment_const_eval_counter(ecx: &mut InterpCx<'mir, 'tcx, Self>) -> InterpResult<'tcx> { // The step limit has already been hit in a previous call to `increment_const_eval_counter`. - if ecx.machine.steps_remaining == 0 { - return Ok(()); - } - ecx.machine.steps_remaining -= 1; - if ecx.machine.steps_remaining == 0 { - throw_exhaust!(StepLimitReached) + if let Some(new_steps) = ecx.machine.num_evaluated_steps.checked_add(1) { + let (limit, start) = if ecx.tcx.sess.opts.unstable_opts.tiny_const_eval_limit { + (TINY_LINT_TERMINATOR_LIMIT, TINY_LINT_TERMINATOR_LIMIT) + } else { + (LINT_TERMINATOR_LIMIT, PROGRESS_INDICATOR_START) + }; + + ecx.machine.num_evaluated_steps = new_steps; + // By default, we have a *deny* lint kicking in after some time + // to ensure `loop {}` doesn't just go forever. + // In case that lint got reduced, in particular for `--cap-lint` situations, we also + // have a hard warning shown every now and then for really long executions. + if new_steps == limit { + // By default, we stop after a million steps, but the user can disable this lint + // to be able to run until the heat death of the universe or power loss, whichever + // comes first. + let hir_id = ecx.best_lint_scope(); + let is_error = ecx + .tcx + .lint_level_at_node( + rustc_session::lint::builtin::LONG_RUNNING_CONST_EVAL, + hir_id, + ) + .0 + .is_error(); + let span = ecx.cur_span(); + ecx.tcx.emit_spanned_lint( + rustc_session::lint::builtin::LONG_RUNNING_CONST_EVAL, + hir_id, + span, + LongRunning { item_span: ecx.tcx.span }, + ); + // If this was a hard error, don't bother continuing evaluation. + if is_error { + let guard = ecx + .tcx + .sess + .delay_span_bug(span, "The deny lint should have already errored"); + throw_inval!(AlreadyReported(guard.into())); + } + } else if new_steps > start && new_steps.is_power_of_two() { + // Only report after a certain number of terminators have been evaluated and the + // current number of evaluated terminators is a power of 2. The latter gives us a cheap + // way to implement exponential backoff. + let span = ecx.cur_span(); + ecx.tcx.sess.emit_warning(LongRunningWarn { span, item_span: ecx.tcx.span }); + } } Ok(()) diff --git a/compiler/rustc_const_eval/src/const_eval/mod.rs b/compiler/rustc_const_eval/src/const_eval/mod.rs index 05be45fef13..6e462d3a1e9 100644 --- a/compiler/rustc_const_eval/src/const_eval/mod.rs +++ b/compiler/rustc_const_eval/src/const_eval/mod.rs @@ -2,10 +2,8 @@ use crate::errors::MaxNumNodesInConstErr; use crate::interpret::{ - intern_const_alloc_recursive, ConstValue, InternKind, InterpCx, InterpResult, MemPlaceMeta, - Scalar, + intern_const_alloc_recursive, ConstValue, InternKind, InterpCx, InterpResult, Scalar, }; -use rustc_hir::Mutability; use rustc_middle::mir; use rustc_middle::mir::interpret::{EvalToValTreeResult, GlobalId}; use rustc_middle::ty::{self, TyCtxt}; @@ -75,17 +73,8 @@ pub(crate) fn eval_to_valtree<'tcx>( let global_const_id = cid.display(tcx); match err { ValTreeCreationError::NodesOverflow => { - let msg = format!( - "maximum number of nodes exceeded in constant {}", - &global_const_id - ); - let mut diag = match tcx.hir().span_if_local(did) { - Some(span) => { - tcx.sess.create_err(MaxNumNodesInConstErr { span, global_const_id }) - } - None => tcx.sess.struct_err(msg), - }; - diag.emit(); + let span = tcx.hir().span_if_local(did); + tcx.sess.emit_err(MaxNumNodesInConstErr { span, global_const_id }); Ok(None) } @@ -131,38 +120,3 @@ pub(crate) fn try_destructure_mir_constant<'tcx>( Ok(mir::DestructuredConstant { variant, fields }) } - -#[instrument(skip(tcx), level = "debug")] -pub(crate) fn deref_mir_constant<'tcx>( - tcx: TyCtxt<'tcx>, - param_env: ty::ParamEnv<'tcx>, - val: mir::ConstantKind<'tcx>, -) -> mir::ConstantKind<'tcx> { - let ecx = mk_eval_cx(tcx, DUMMY_SP, param_env, false); - let op = ecx.eval_mir_constant(&val, None, None).unwrap(); - let mplace = ecx.deref_operand(&op).unwrap(); - if let Some(alloc_id) = mplace.ptr.provenance { - assert_eq!( - tcx.global_alloc(alloc_id).unwrap_memory().0.0.mutability, - Mutability::Not, - "deref_mir_constant cannot be used with mutable allocations as \ - that could allow pattern matching to observe mutable statics", - ); - } - - let ty = match mplace.meta { - MemPlaceMeta::None => mplace.layout.ty, - // In case of unsized types, figure out the real type behind. - MemPlaceMeta::Meta(scalar) => match mplace.layout.ty.kind() { - ty::Str => bug!("there's no sized equivalent of a `str`"), - ty::Slice(elem_ty) => tcx.mk_array(*elem_ty, scalar.to_target_usize(&tcx).unwrap()), - _ => bug!( - "type {} should not have metadata, but had {:?}", - mplace.layout.ty, - mplace.meta - ), - }, - }; - - mir::ConstantKind::Val(op_to_const(&ecx, &mplace.into()), ty) -} |