69 lines
2.6 KiB
Rust
69 lines
2.6 KiB
Rust
// Not in interpret to make sure we do not use private implementation details
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use std::convert::TryFrom;
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use rustc_middle::mir;
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use rustc_middle::ty::{self, TyCtxt};
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use rustc_span::{source_map::DUMMY_SP, symbol::Symbol};
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use crate::interpret::{intern_const_alloc_recursive, ConstValue, InternKind, InterpCx};
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mod error;
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mod eval_queries;
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mod fn_queries;
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mod machine;
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pub use error::*;
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pub use eval_queries::*;
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pub use fn_queries::*;
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pub use machine::*;
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pub(crate) fn const_caller_location(
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tcx: TyCtxt<'tcx>,
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(file, line, col): (Symbol, u32, u32),
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) -> ConstValue<'tcx> {
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trace!("const_caller_location: {}:{}:{}", file, line, col);
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let mut ecx = mk_eval_cx(tcx, DUMMY_SP, ty::ParamEnv::reveal_all(), false);
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let loc_place = ecx.alloc_caller_location(file, line, col);
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intern_const_alloc_recursive(&mut ecx, InternKind::Constant, loc_place, false);
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ConstValue::Scalar(loc_place.ptr)
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}
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/// This function uses `unwrap` copiously, because an already validated constant
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/// must have valid fields and can thus never fail outside of compiler bugs. However, it is
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/// invoked from the pretty printer, where it can receive enums with no variants and e.g.
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/// `read_discriminant` needs to be able to handle that.
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pub(crate) fn destructure_const<'tcx>(
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tcx: TyCtxt<'tcx>,
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param_env: ty::ParamEnv<'tcx>,
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val: &'tcx ty::Const<'tcx>,
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) -> mir::DestructuredConst<'tcx> {
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trace!("destructure_const: {:?}", val);
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let ecx = mk_eval_cx(tcx, DUMMY_SP, param_env, false);
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let op = ecx.const_to_op(val, None).unwrap();
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// We go to `usize` as we cannot allocate anything bigger anyway.
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let (field_count, variant, down) = match val.ty.kind() {
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ty::Array(_, len) => (usize::try_from(len.eval_usize(tcx, param_env)).unwrap(), None, op),
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ty::Adt(def, _) if def.variants.is_empty() => {
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return mir::DestructuredConst { variant: None, fields: tcx.arena.alloc_slice(&[]) };
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}
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ty::Adt(def, _) => {
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let variant = ecx.read_discriminant(op).unwrap().1;
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let down = ecx.operand_downcast(op, variant).unwrap();
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(def.variants[variant].fields.len(), Some(variant), down)
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}
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ty::Tuple(substs) => (substs.len(), None, op),
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_ => bug!("cannot destructure constant {:?}", val),
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};
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let fields_iter = (0..field_count).map(|i| {
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let field_op = ecx.operand_field(down, i).unwrap();
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let val = op_to_const(&ecx, field_op);
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ty::Const::from_value(tcx, val, field_op.layout.ty)
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});
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let fields = tcx.arena.alloc_from_iter(fields_iter);
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mir::DestructuredConst { variant, fields }
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}
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