diff --git a/compiler/rustc_middle/src/lib.rs b/compiler/rustc_middle/src/lib.rs index 649913dd025b5..57f507290e894 100644 --- a/compiler/rustc_middle/src/lib.rs +++ b/compiler/rustc_middle/src/lib.rs @@ -48,6 +48,7 @@ #![feature(associated_type_defaults)] #![feature(iter_zip)] #![feature(thread_local_const_init)] +#![feature(try_reserve)] #![recursion_limit = "512"] #[macro_use] diff --git a/compiler/rustc_middle/src/mir/interpret/allocation.rs b/compiler/rustc_middle/src/mir/interpret/allocation.rs index ee3902991e911..f1b1bb9ab88ab 100644 --- a/compiler/rustc_middle/src/mir/interpret/allocation.rs +++ b/compiler/rustc_middle/src/mir/interpret/allocation.rs @@ -8,12 +8,15 @@ use std::ptr; use rustc_ast::Mutability; use rustc_data_structures::sorted_map::SortedMap; +use rustc_span::DUMMY_SP; use rustc_target::abi::{Align, HasDataLayout, Size}; use super::{ - read_target_uint, write_target_uint, AllocId, InterpError, Pointer, Scalar, ScalarMaybeUninit, - UndefinedBehaviorInfo, UninitBytesAccess, UnsupportedOpInfo, + read_target_uint, write_target_uint, AllocId, InterpError, InterpResult, Pointer, + ResourceExhaustionInfo, Scalar, ScalarMaybeUninit, UndefinedBehaviorInfo, UninitBytesAccess, + UnsupportedOpInfo, }; +use crate::ty; /// This type represents an Allocation in the Miri/CTFE core engine. /// @@ -121,15 +124,33 @@ impl Allocation { Allocation::from_bytes(slice, Align::ONE, Mutability::Not) } - pub fn uninit(size: Size, align: Align) -> Self { - Allocation { - bytes: vec![0; size.bytes_usize()], + /// Try to create an Allocation of `size` bytes, failing if there is not enough memory + /// available to the compiler to do so. + pub fn uninit(size: Size, align: Align, panic_on_fail: bool) -> InterpResult<'static, Self> { + let mut bytes = Vec::new(); + bytes.try_reserve(size.bytes_usize()).map_err(|_| { + // This results in an error that can happen non-deterministically, since the memory + // available to the compiler can change between runs. Normally queries are always + // deterministic. However, we can be non-determinstic here because all uses of const + // evaluation (including ConstProp!) will make compilation fail (via hard error + // or ICE) upon encountering a `MemoryExhausted` error. + if panic_on_fail { + panic!("Allocation::uninit called with panic_on_fail had allocation failure") + } + ty::tls::with(|tcx| { + tcx.sess.delay_span_bug(DUMMY_SP, "exhausted memory during interpreation") + }); + InterpError::ResourceExhaustion(ResourceExhaustionInfo::MemoryExhausted) + })?; + bytes.resize(size.bytes_usize(), 0); + Ok(Allocation { + bytes, relocations: Relocations::new(), init_mask: InitMask::new(size, false), align, mutability: Mutability::Mut, extra: (), - } + }) } } diff --git a/compiler/rustc_middle/src/mir/interpret/error.rs b/compiler/rustc_middle/src/mir/interpret/error.rs index cb2a355697dd0..ab9239585c4aa 100644 --- a/compiler/rustc_middle/src/mir/interpret/error.rs +++ b/compiler/rustc_middle/src/mir/interpret/error.rs @@ -423,6 +423,8 @@ pub enum ResourceExhaustionInfo { /// /// The exact limit is set by the `const_eval_limit` attribute. StepLimitReached, + /// There is not enough memory to perform an allocation. + MemoryExhausted, } impl fmt::Display for ResourceExhaustionInfo { @@ -435,6 +437,9 @@ impl fmt::Display for ResourceExhaustionInfo { StepLimitReached => { write!(f, "exceeded interpreter step limit (see `#[const_eval_limit]`)") } + MemoryExhausted => { + write!(f, "tried to allocate more memory than available to compiler") + } } } } @@ -525,7 +530,8 @@ impl InterpError<'_> { use InterpError::*; match *self { MachineStop(ref err) => err.is_hard_err(), - InterpError::UndefinedBehavior(_) => true, + UndefinedBehavior(_) => true, + ResourceExhaustion(ResourceExhaustionInfo::MemoryExhausted) => true, _ => false, } } diff --git a/compiler/rustc_middle/src/ty/vtable.rs b/compiler/rustc_middle/src/ty/vtable.rs index 3a35d8c88a478..0940137a7c33f 100644 --- a/compiler/rustc_middle/src/ty/vtable.rs +++ b/compiler/rustc_middle/src/ty/vtable.rs @@ -60,7 +60,8 @@ impl<'tcx> TyCtxt<'tcx> { let ptr_align = tcx.data_layout.pointer_align.abi; let vtable_size = ptr_size * u64::try_from(vtable_entries.len()).unwrap(); - let mut vtable = Allocation::uninit(vtable_size, ptr_align); + let mut vtable = + Allocation::uninit(vtable_size, ptr_align, /* panic_on_fail */ true).unwrap(); // No need to do any alignment checks on the memory accesses below, because we know the // allocation is correctly aligned as we created it above. Also we're only offsetting by diff --git a/compiler/rustc_mir/src/const_eval/eval_queries.rs b/compiler/rustc_mir/src/const_eval/eval_queries.rs index 536dbad4f764d..7a7dbe50e72f9 100644 --- a/compiler/rustc_mir/src/const_eval/eval_queries.rs +++ b/compiler/rustc_mir/src/const_eval/eval_queries.rs @@ -48,7 +48,7 @@ fn eval_body_using_ecx<'mir, 'tcx>( ); let layout = ecx.layout_of(body.return_ty().subst(tcx, cid.instance.substs))?; assert!(!layout.is_unsized()); - let ret = ecx.allocate(layout, MemoryKind::Stack); + let ret = ecx.allocate(layout, MemoryKind::Stack)?; let name = with_no_trimmed_paths(|| ty::tls::with(|tcx| tcx.def_path_str(cid.instance.def_id()))); diff --git a/compiler/rustc_mir/src/const_eval/machine.rs b/compiler/rustc_mir/src/const_eval/machine.rs index 773df7d7b60c1..992e32e298f8e 100644 --- a/compiler/rustc_mir/src/const_eval/machine.rs +++ b/compiler/rustc_mir/src/const_eval/machine.rs @@ -201,6 +201,8 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir, type MemoryExtra = MemoryExtra; + const PANIC_ON_ALLOC_FAIL: bool = false; // will be raised as a proper error + fn load_mir( ecx: &InterpCx<'mir, 'tcx, Self>, instance: ty::InstanceDef<'tcx>, @@ -306,7 +308,7 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir, Size::from_bytes(size as u64), align, interpret::MemoryKind::Machine(MemoryKind::Heap), - ); + )?; ecx.write_scalar(Scalar::Ptr(ptr), dest)?; } _ => { diff --git a/compiler/rustc_mir/src/interpret/intern.rs b/compiler/rustc_mir/src/interpret/intern.rs index d5fec457fa19e..2862670dc7c46 100644 --- a/compiler/rustc_mir/src/interpret/intern.rs +++ b/compiler/rustc_mir/src/interpret/intern.rs @@ -428,7 +428,7 @@ impl<'mir, 'tcx: 'mir, M: super::intern::CompileTimeMachine<'mir, 'tcx, !>> &MPlaceTy<'tcx, M::PointerTag>, ) -> InterpResult<'tcx, ()>, ) -> InterpResult<'tcx, &'tcx Allocation> { - let dest = self.allocate(layout, MemoryKind::Stack); + let dest = self.allocate(layout, MemoryKind::Stack)?; f(self, &dest)?; let ptr = dest.ptr.assert_ptr(); assert_eq!(ptr.offset, Size::ZERO); diff --git a/compiler/rustc_mir/src/interpret/intrinsics/caller_location.rs b/compiler/rustc_mir/src/interpret/intrinsics/caller_location.rs index 792a4749108be..4a3278030b5d9 100644 --- a/compiler/rustc_mir/src/interpret/intrinsics/caller_location.rs +++ b/compiler/rustc_mir/src/interpret/intrinsics/caller_location.rs @@ -91,7 +91,9 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> { .type_of(self.tcx.require_lang_item(LangItem::PanicLocation, None)) .subst(*self.tcx, self.tcx.mk_substs([self.tcx.lifetimes.re_erased.into()].iter())); let loc_layout = self.layout_of(loc_ty).unwrap(); - let location = self.allocate(loc_layout, MemoryKind::CallerLocation); + // This can fail if rustc runs out of memory right here. Trying to emit an error would be + // pointless, since that would require allocating more memory than a Location. + let location = self.allocate(loc_layout, MemoryKind::CallerLocation).unwrap(); // Initialize fields. self.write_immediate(file.to_ref(), &self.mplace_field(&location, 0).unwrap().into()) diff --git a/compiler/rustc_mir/src/interpret/machine.rs b/compiler/rustc_mir/src/interpret/machine.rs index 0d01dc3c219bc..5b8c0788cbc84 100644 --- a/compiler/rustc_mir/src/interpret/machine.rs +++ b/compiler/rustc_mir/src/interpret/machine.rs @@ -122,6 +122,9 @@ pub trait Machine<'mir, 'tcx>: Sized { /// that is added to the memory so that the work is not done twice. const GLOBAL_KIND: Option; + /// Should the machine panic on allocation failures? + const PANIC_ON_ALLOC_FAIL: bool; + /// Whether memory accesses should be alignment-checked. fn enforce_alignment(memory_extra: &Self::MemoryExtra) -> bool; diff --git a/compiler/rustc_mir/src/interpret/memory.rs b/compiler/rustc_mir/src/interpret/memory.rs index 94506808a68c3..cb929c21850cb 100644 --- a/compiler/rustc_mir/src/interpret/memory.rs +++ b/compiler/rustc_mir/src/interpret/memory.rs @@ -207,9 +207,9 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> { size: Size, align: Align, kind: MemoryKind, - ) -> Pointer { - let alloc = Allocation::uninit(size, align); - self.allocate_with(alloc, kind) + ) -> InterpResult<'static, Pointer> { + let alloc = Allocation::uninit(size, align, M::PANIC_ON_ALLOC_FAIL)?; + Ok(self.allocate_with(alloc, kind)) } pub fn allocate_bytes( @@ -257,7 +257,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> { // For simplicities' sake, we implement reallocate as "alloc, copy, dealloc". // This happens so rarely, the perf advantage is outweighed by the maintenance cost. - let new_ptr = self.allocate(new_size, new_align, kind); + let new_ptr = self.allocate(new_size, new_align, kind)?; let old_size = match old_size_and_align { Some((size, _align)) => size, None => self.get_raw(ptr.alloc_id)?.size(), diff --git a/compiler/rustc_mir/src/interpret/place.rs b/compiler/rustc_mir/src/interpret/place.rs index 4c53510ed00ee..42a304ce41213 100644 --- a/compiler/rustc_mir/src/interpret/place.rs +++ b/compiler/rustc_mir/src/interpret/place.rs @@ -982,7 +982,7 @@ where let (size, align) = self .size_and_align_of(&meta, &local_layout)? .expect("Cannot allocate for non-dyn-sized type"); - let ptr = self.memory.allocate(size, align, MemoryKind::Stack); + let ptr = self.memory.allocate(size, align, MemoryKind::Stack)?; let mplace = MemPlace { ptr: ptr.into(), align, meta }; if let LocalValue::Live(Operand::Immediate(value)) = local_val { // Preserve old value. @@ -1018,9 +1018,9 @@ where &mut self, layout: TyAndLayout<'tcx>, kind: MemoryKind, - ) -> MPlaceTy<'tcx, M::PointerTag> { - let ptr = self.memory.allocate(layout.size, layout.align.abi, kind); - MPlaceTy::from_aligned_ptr(ptr, layout) + ) -> InterpResult<'static, MPlaceTy<'tcx, M::PointerTag>> { + let ptr = self.memory.allocate(layout.size, layout.align.abi, kind)?; + Ok(MPlaceTy::from_aligned_ptr(ptr, layout)) } /// Returns a wide MPlace of type `&'static [mut] str` to a new 1-aligned allocation. diff --git a/compiler/rustc_mir/src/lib.rs b/compiler/rustc_mir/src/lib.rs index 1da17bddcb777..a58ded9cfd3a4 100644 --- a/compiler/rustc_mir/src/lib.rs +++ b/compiler/rustc_mir/src/lib.rs @@ -29,6 +29,7 @@ Rust MIR: a lowered representation of Rust. #![feature(option_get_or_insert_default)] #![feature(once_cell)] #![feature(control_flow_enum)] +#![feature(try_reserve)] #![recursion_limit = "256"] #[macro_use] diff --git a/compiler/rustc_mir/src/transform/const_prop.rs b/compiler/rustc_mir/src/transform/const_prop.rs index b56c247127ce4..e9b68754bdf80 100644 --- a/compiler/rustc_mir/src/transform/const_prop.rs +++ b/compiler/rustc_mir/src/transform/const_prop.rs @@ -181,6 +181,7 @@ impl<'mir, 'tcx> ConstPropMachine<'mir, 'tcx> { impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for ConstPropMachine<'mir, 'tcx> { compile_time_machine!(<'mir, 'tcx>); + const PANIC_ON_ALLOC_FAIL: bool = true; // all allocations are small (see `MAX_ALLOC_LIMIT`) type MemoryKind = !; @@ -393,7 +394,11 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> { .filter(|ret_layout| { !ret_layout.is_zst() && ret_layout.size < Size::from_bytes(MAX_ALLOC_LIMIT) }) - .map(|ret_layout| ecx.allocate(ret_layout, MemoryKind::Stack).into()); + .map(|ret_layout| { + ecx.allocate(ret_layout, MemoryKind::Stack) + .expect("couldn't perform small allocation") + .into() + }); ecx.push_stack_frame( Instance::new(def_id, substs), diff --git a/src/test/ui/consts/large_const_alloc.rs b/src/test/ui/consts/large_const_alloc.rs new file mode 100644 index 0000000000000..54abaab224730 --- /dev/null +++ b/src/test/ui/consts/large_const_alloc.rs @@ -0,0 +1,18 @@ +// only-64bit +// on 32bit and 16bit platforms it is plausible that the maximum allocation size will succeed + +const FOO: () = { + // 128 TiB, unlikely anyone has that much RAM + let x = [0_u8; (1 << 47) - 1]; + //~^ ERROR evaluation of constant value failed +}; + +static FOO2: () = { + let x = [0_u8; (1 << 47) - 1]; + //~^ ERROR could not evaluate static initializer +}; + +fn main() { + let _ = FOO; + let _ = FOO2; +} diff --git a/src/test/ui/consts/large_const_alloc.stderr b/src/test/ui/consts/large_const_alloc.stderr new file mode 100644 index 0000000000000..25d660f1217f4 --- /dev/null +++ b/src/test/ui/consts/large_const_alloc.stderr @@ -0,0 +1,15 @@ +error[E0080]: evaluation of constant value failed + --> $DIR/large_const_alloc.rs:6:13 + | +LL | let x = [0_u8; (1 << 47) - 1]; + | ^^^^^^^^^^^^^^^^^^^^^ tried to allocate more memory than available to compiler + +error[E0080]: could not evaluate static initializer + --> $DIR/large_const_alloc.rs:11:13 + | +LL | let x = [0_u8; (1 << 47) - 1]; + | ^^^^^^^^^^^^^^^^^^^^^ tried to allocate more memory than available to compiler + +error: aborting due to 2 previous errors + +For more information about this error, try `rustc --explain E0080`.