diff options
Diffstat (limited to 'compiler/rustc_middle/src/mir/consts.rs')
| -rw-r--r-- | compiler/rustc_middle/src/mir/consts.rs | 63 |
1 files changed, 33 insertions, 30 deletions
diff --git a/compiler/rustc_middle/src/mir/consts.rs b/compiler/rustc_middle/src/mir/consts.rs index fb941977528..96131d47a17 100644 --- a/compiler/rustc_middle/src/mir/consts.rs +++ b/compiler/rustc_middle/src/mir/consts.rs @@ -9,9 +9,7 @@ use rustc_span::{DUMMY_SP, Span, Symbol}; use rustc_type_ir::TypeVisitableExt; use super::interpret::ReportedErrorInfo; -use crate::mir::interpret::{ - AllocId, AllocRange, ConstAllocation, ErrorHandled, GlobalAlloc, Scalar, alloc_range, -}; +use crate::mir::interpret::{AllocId, AllocRange, ErrorHandled, GlobalAlloc, Scalar, alloc_range}; use crate::mir::{Promoted, pretty_print_const_value}; use crate::ty::print::{pretty_print_const, with_no_trimmed_paths}; use crate::ty::{self, ConstKind, GenericArgsRef, ScalarInt, Ty, TyCtxt}; @@ -33,8 +31,8 @@ pub struct ConstAlloc<'tcx> { /// Represents a constant value in Rust. `Scalar` and `Slice` are optimizations for /// array length computations, enum discriminants and the pattern matching logic. #[derive(Copy, Clone, Debug, Eq, PartialEq, TyEncodable, TyDecodable, Hash)] -#[derive(HashStable, Lift)] -pub enum ConstValue<'tcx> { +#[derive(HashStable)] +pub enum ConstValue { /// Used for types with `layout::abi::Scalar` ABI. /// /// Not using the enum `Value` to encode that this must not be `Uninit`. @@ -52,7 +50,7 @@ pub enum ConstValue<'tcx> { Slice { /// The allocation storing the slice contents. /// This always points to the beginning of the allocation. - data: ConstAllocation<'tcx>, + alloc_id: AllocId, /// The metadata field of the reference. /// This is a "target usize", so we use `u64` as in the interpreter. meta: u64, @@ -75,9 +73,9 @@ pub enum ConstValue<'tcx> { } #[cfg(target_pointer_width = "64")] -rustc_data_structures::static_assert_size!(ConstValue<'_>, 24); +rustc_data_structures::static_assert_size!(ConstValue, 24); -impl<'tcx> ConstValue<'tcx> { +impl ConstValue { #[inline] pub fn try_to_scalar(&self) -> Option<Scalar> { match *self { @@ -98,11 +96,11 @@ impl<'tcx> ConstValue<'tcx> { self.try_to_scalar_int()?.try_into().ok() } - pub fn try_to_target_usize(&self, tcx: TyCtxt<'tcx>) -> Option<u64> { + pub fn try_to_target_usize(&self, tcx: TyCtxt<'_>) -> Option<u64> { Some(self.try_to_scalar_int()?.to_target_usize(tcx)) } - pub fn try_to_bits_for_ty( + pub fn try_to_bits_for_ty<'tcx>( &self, tcx: TyCtxt<'tcx>, typing_env: ty::TypingEnv<'tcx>, @@ -132,12 +130,15 @@ impl<'tcx> ConstValue<'tcx> { } /// Must only be called on constants of type `&str` or `&[u8]`! - pub fn try_get_slice_bytes_for_diagnostics(&self, tcx: TyCtxt<'tcx>) -> Option<&'tcx [u8]> { - let (data, start, end) = match self { + pub fn try_get_slice_bytes_for_diagnostics<'tcx>( + &self, + tcx: TyCtxt<'tcx>, + ) -> Option<&'tcx [u8]> { + let (alloc_id, start, len) = match self { ConstValue::Scalar(_) | ConstValue::ZeroSized => { bug!("`try_get_slice_bytes` on non-slice constant") } - &ConstValue::Slice { data, meta } => (data, 0, meta), + &ConstValue::Slice { alloc_id, meta } => (alloc_id, 0, meta), &ConstValue::Indirect { alloc_id, offset } => { // The reference itself is stored behind an indirection. // Load the reference, and then load the actual slice contents. @@ -170,26 +171,29 @@ impl<'tcx> ConstValue<'tcx> { // Non-empty slice, must have memory. We know this is a relative pointer. let (inner_prov, offset) = ptr.into_pointer_or_addr().ok()?.prov_and_relative_offset(); - let data = tcx.global_alloc(inner_prov.alloc_id()).unwrap_memory(); - (data, offset.bytes(), offset.bytes() + len) + (inner_prov.alloc_id(), offset.bytes(), len) } }; + let data = tcx.global_alloc(alloc_id).unwrap_memory(); + // This is for diagnostics only, so we are okay to use `inspect_with_uninit_and_ptr_outside_interpreter`. let start = start.try_into().unwrap(); - let end = end.try_into().unwrap(); + let end = start + usize::try_from(len).unwrap(); Some(data.inner().inspect_with_uninit_and_ptr_outside_interpreter(start..end)) } /// Check if a constant may contain provenance information. This is used by MIR opts. /// Can return `true` even if there is no provenance. - pub fn may_have_provenance(&self, tcx: TyCtxt<'tcx>, size: Size) -> bool { + pub fn may_have_provenance(&self, tcx: TyCtxt<'_>, size: Size) -> bool { match *self { ConstValue::ZeroSized | ConstValue::Scalar(Scalar::Int(_)) => return false, ConstValue::Scalar(Scalar::Ptr(..)) => return true, // It's hard to find out the part of the allocation we point to; // just conservatively check everything. - ConstValue::Slice { data, meta: _ } => !data.inner().provenance().ptrs().is_empty(), + ConstValue::Slice { alloc_id, meta: _ } => { + !tcx.global_alloc(alloc_id).unwrap_memory().inner().provenance().ptrs().is_empty() + } ConstValue::Indirect { alloc_id, offset } => !tcx .global_alloc(alloc_id) .unwrap_memory() @@ -200,7 +204,7 @@ impl<'tcx> ConstValue<'tcx> { } /// Check if a constant only contains uninitialized bytes. - pub fn all_bytes_uninit(&self, tcx: TyCtxt<'tcx>) -> bool { + pub fn all_bytes_uninit(&self, tcx: TyCtxt<'_>) -> bool { let ConstValue::Indirect { alloc_id, .. } = self else { return false; }; @@ -247,7 +251,7 @@ pub enum Const<'tcx> { /// This constant cannot go back into the type system, as it represents /// something the type system cannot handle (e.g. pointers). - Val(ConstValue<'tcx>, Ty<'tcx>), + Val(ConstValue, Ty<'tcx>), } impl<'tcx> Const<'tcx> { @@ -343,7 +347,7 @@ impl<'tcx> Const<'tcx> { tcx: TyCtxt<'tcx>, typing_env: ty::TypingEnv<'tcx>, span: Span, - ) -> Result<ConstValue<'tcx>, ErrorHandled> { + ) -> Result<ConstValue, ErrorHandled> { match self { Const::Ty(_, c) => { if c.has_non_region_param() { @@ -440,7 +444,7 @@ impl<'tcx> Const<'tcx> { } #[inline] - pub fn from_value(val: ConstValue<'tcx>, ty: Ty<'tcx>) -> Self { + pub fn from_value(val: ConstValue, ty: Ty<'tcx>) -> Self { Self::Val(val, ty) } @@ -487,9 +491,8 @@ impl<'tcx> Const<'tcx> { /// taking into account even pointer identity tests. pub fn is_deterministic(&self) -> bool { // Some constants may generate fresh allocations for pointers they contain, - // so using the same constant twice can yield two different results: - // - valtrees purposefully generate new allocations - // - ConstValue::Slice also generate new allocations + // so using the same constant twice can yield two different results. + // Notably, valtrees purposefully generate new allocations. match self { Const::Ty(_, c) => match c.kind() { ty::ConstKind::Param(..) => true, @@ -507,11 +510,11 @@ impl<'tcx> Const<'tcx> { | ty::ConstKind::Placeholder(..) => bug!(), }, Const::Unevaluated(..) => false, - // If the same slice appears twice in the MIR, we cannot guarantee that we will - // give the same `AllocId` to the data. - Const::Val(ConstValue::Slice { .. }, _) => false, Const::Val( - ConstValue::ZeroSized | ConstValue::Scalar(_) | ConstValue::Indirect { .. }, + ConstValue::Slice { .. } + | ConstValue::ZeroSized + | ConstValue::Scalar(_) + | ConstValue::Indirect { .. }, _, ) => true, } @@ -574,7 +577,7 @@ impl<'tcx> Display for Const<'tcx> { /// Const-related utilities impl<'tcx> TyCtxt<'tcx> { - pub fn span_as_caller_location(self, span: Span) -> ConstValue<'tcx> { + pub fn span_as_caller_location(self, span: Span) -> ConstValue { let topmost = span.ctxt().outer_expn().expansion_cause().unwrap_or(span); let caller = self.sess.source_map().lookup_char_pos(topmost.lo()); self.const_caller_location( |