| // Not in interpret to make sure we do not use private implementation details |
| |
| use rustc::mir; |
| use rustc::ty::layout::VariantIdx; |
| use rustc::ty::{self, TyCtxt}; |
| use rustc_span::{source_map::DUMMY_SP, symbol::Symbol}; |
| |
| use crate::interpret::{intern_const_alloc_recursive, ConstValue, InternKind, InterpCx}; |
| |
| mod error; |
| mod eval_queries; |
| mod fn_queries; |
| mod machine; |
| |
| pub use error::*; |
| pub use eval_queries::*; |
| pub use fn_queries::*; |
| pub use machine::*; |
| |
| /// Extracts a field of a (variant of a) const. |
| // this function uses `unwrap` copiously, because an already validated constant must have valid |
| // fields and can thus never fail outside of compiler bugs |
| pub(crate) fn const_field<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| param_env: ty::ParamEnv<'tcx>, |
| variant: Option<VariantIdx>, |
| field: mir::Field, |
| value: &'tcx ty::Const<'tcx>, |
| ) -> &'tcx ty::Const<'tcx> { |
| trace!("const_field: {:?}, {:?}", field, value); |
| let ecx = mk_eval_cx(tcx, DUMMY_SP, param_env, false); |
| // get the operand again |
| let op = ecx.eval_const_to_op(value, None).unwrap(); |
| // downcast |
| let down = match variant { |
| None => op, |
| Some(variant) => ecx.operand_downcast(op, variant).unwrap(), |
| }; |
| // then project |
| let field = ecx.operand_field(down, field.index() as u64).unwrap(); |
| // and finally move back to the const world, always normalizing because |
| // this is not called for statics. |
| op_to_const(&ecx, field) |
| } |
| |
| pub(crate) fn const_caller_location<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| (file, line, col): (Symbol, u32, u32), |
| ) -> &'tcx ty::Const<'tcx> { |
| trace!("const_caller_location: {}:{}:{}", file, line, col); |
| let mut ecx = mk_eval_cx(tcx, DUMMY_SP, ty::ParamEnv::reveal_all(), false); |
| |
| let loc_ty = tcx.caller_location_ty(); |
| let loc_place = ecx.alloc_caller_location(file, line, col); |
| intern_const_alloc_recursive(&mut ecx, InternKind::Constant, loc_place, false).unwrap(); |
| let loc_const = ty::Const { |
| ty: loc_ty, |
| val: ty::ConstKind::Value(ConstValue::Scalar(loc_place.ptr.into())), |
| }; |
| |
| tcx.mk_const(loc_const) |
| } |
| |
| // this function uses `unwrap` copiously, because an already validated constant |
| // must have valid fields and can thus never fail outside of compiler bugs |
| pub(crate) fn destructure_const<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| param_env: ty::ParamEnv<'tcx>, |
| val: &'tcx ty::Const<'tcx>, |
| ) -> mir::DestructuredConst<'tcx> { |
| trace!("destructure_const: {:?}", val); |
| let ecx = mk_eval_cx(tcx, DUMMY_SP, param_env, false); |
| let op = ecx.eval_const_to_op(val, None).unwrap(); |
| |
| let variant = ecx.read_discriminant(op).unwrap().1; |
| |
| let field_count = match val.ty.kind { |
| ty::Array(_, len) => len.eval_usize(tcx, param_env), |
| ty::Adt(def, _) => def.variants[variant].fields.len() as u64, |
| ty::Tuple(substs) => substs.len() as u64, |
| _ => bug!("cannot destructure constant {:?}", val), |
| }; |
| |
| let down = ecx.operand_downcast(op, variant).unwrap(); |
| let fields_iter = (0..field_count).map(|i| { |
| let field_op = ecx.operand_field(down, i).unwrap(); |
| op_to_const(&ecx, field_op) |
| }); |
| let fields = tcx.arena.alloc_from_iter(fields_iter); |
| |
| mir::DestructuredConst { variant, fields } |
| } |