compiler/rustc_const_eval/src/might_permit_raw_init.rs

   1 use crate::const_eval::CompileTimeInterpreter;
   2 use crate::interpret::{InterpCx, MemoryKind, OpTy};
   3 use rustc_middle::ty::layout::LayoutCx;
   4 use rustc_middle::ty::{layout::TyAndLayout, ParamEnv, TyCtxt};
   5 use rustc_session::Limit;
   6 use rustc_target::abi::InitKind;
   7
   8 pub fn might_permit_raw_init<'tcx>(
   9     tcx: TyCtxt<'tcx>,
  10     ty: TyAndLayout<'tcx>,
  11     kind: InitKind,
  12 ) -> bool {
  13     let strict = tcx.sess.opts.unstable_opts.strict_init_checks;
  14
  15     if strict {
  16         let machine = CompileTimeInterpreter::new(
  17             Limit::new(0),
  18             /*can_access_statics:*/ false,
  19             /*check_alignment:*/ true,
  20         );
  21
  22         let mut cx = InterpCx::new(tcx, rustc_span::DUMMY_SP, ParamEnv::reveal_all(), machine);
  23
  24         let allocated = cx
  25             .allocate(ty, MemoryKind::Machine(crate::const_eval::MemoryKind::Heap))
  26             .expect("OOM: failed to allocate for uninit check");
  27
  28         if kind == InitKind::Zero {
  29             cx.write_bytes_ptr(
  30                 allocated.ptr,
  31                 std::iter::repeat(0_u8).take(ty.layout.size().bytes_usize()),
  32             )
  33             .expect("failed to write bytes for zero valid check");
  34         }
  35
  36         let ot: OpTy<'_, _> = allocated.into();
  37
  38         // Assume that if it failed, it's a validation failure.
  39         cx.validate_operand(&ot).is_ok()
  40     } else {
  41         let layout_cx = LayoutCx { tcx, param_env: ParamEnv::reveal_all() };
  42         ty.might_permit_raw_init(&layout_cx, kind)
  43     }
  44 }