Struct rustc_mir_transform::promote_consts::Validator

struct Validator<'a, 'tcx> {
    ccx: &'a ConstCx<'a, 'tcx>,
    temps: &'a mut IndexSlice<Local, TempState>,
    promotion_safe_blocks: Option<FxHashSet<BasicBlock>>,
}

Checks whether locals that appear in a promotion context (Candidate) are actually promotable.

This wraps an Item, and has access to all fields of that Item via Deref coercion.

Fields

ccx: &'a ConstCx<'a, 'tcx>

temps: &'a mut IndexSlice<Local, TempState>

promotion_safe_blocks: Option<FxHashSet<BasicBlock>>

For backwards compatibility, we are promoting function calls in const/static initializers. But we want to avoid evaluating code that might panic and that otherwise would not have been evaluated, so we only promote such calls in basic blocks that are guaranteed to execute. In other words, we only promote such calls in basic blocks that are definitely not dead code. Here we cache the result of computing that set of basic blocks.

Implementations

impl<'tcx> Validator<'_, 'tcx>

fn validate_candidate( &mut self, candidate: Candidate ) -> Result<(), Unpromotable>

fn qualif_local<Q: Qualif>(&mut self, local: Local) -> bool

fn validate_local(&mut self, local: Local) -> Result<(), Unpromotable>

fn validate_place(&mut self, place: PlaceRef<'tcx>) -> Result<(), Unpromotable>

fn validate_operand( &mut self, operand: &Operand<'tcx> ) -> Result<(), Unpromotable>

fn validate_ref( &mut self, kind: BorrowKind, place: &Place<'tcx> ) -> Result<(), Unpromotable>

fn validate_rvalue(&mut self, rvalue: &Rvalue<'tcx>) -> Result<(), Unpromotable>

fn promotion_safe_blocks(body: &Body<'tcx>) -> FxHashSet<BasicBlock>

Computes the sets of blocks of this MIR that are definitely going to be executed if the function returns successfully. That makes it safe to promote calls in them that might fail.

fn is_promotion_safe_block(&mut self, block: BasicBlock) -> bool

Returns whether the block is “safe” for promotion, which means it cannot be dead code. We use this to avoid promoting operations that can fail in dead code.

fn validate_call( &mut self, callee: &Operand<'tcx>, args: &[Spanned<Operand<'tcx>>], block: BasicBlock ) -> Result<(), Unpromotable>

Methods from Deref<Target = ConstCx<'a, 'tcx>>

pub fn def_id(&self) -> LocalDefId

pub fn const_kind(&self) -> ConstContext

Returns the kind of const context this Item represents (const, static, etc.).

Panics if this Item is not const.

pub fn is_const_stable_const_fn(&self) -> bool

pub fn fn_sig(&self) -> Binder<'tcx, FnSig<'tcx>>

Trait Implementations

impl<'a, 'tcx> Deref for Validator<'a, 'tcx>

type Target = ConstCx<'a, 'tcx>

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 56 bytes