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Allow easily creating cheap eval context instances

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This commit is contained in:
Oliver Schneider 2017-12-15 08:55:54 +01:00
parent 9331031909
commit 2d161f10e5
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GPG Key ID: A69F8D225B3AD7D9
2 changed files with 66 additions and 57 deletions
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121
src/librustc_mir/interpret/const_eval.rs
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@ -20,11 +20,32 @@ use rustc_const_math::ConstInt;
use std::fmt;
use std::error::Error;
pub fn mk_eval_cx<'a, 'tcx>(
tcx: TyCtxt<'a, 'tcx, 'tcx>,
instance: Instance<'tcx>,
param_env: ty::ParamEnv<'tcx>,
) -> EvalResult<'tcx, EvalContext<'a, 'tcx, CompileTimeEvaluator>> {
debug!("mk_eval_cx: {:?}, {:?}", instance, param_env);
let limits = super::ResourceLimits::default();
let mut ecx = EvalContext::new(tcx, param_env, limits, CompileTimeEvaluator, ());
let mir = ecx.load_mir(instance.def)?;
// insert a stack frame so any queries have the correct substs
ecx.push_stack_frame(
instance,
mir.span,
mir,
Place::undef(),
StackPopCleanup::None,
)?;
Ok(ecx)
}
pub fn eval_body<'a, 'tcx>(
tcx: TyCtxt<'a, 'tcx, 'tcx>,
instance: Instance<'tcx>,
param_env: ty::ParamEnv<'tcx>,
) -> (EvalResult<'tcx, (PtrAndAlign, Ty<'tcx>)>, EvalContext<'a, 'tcx, CompileTimeEvaluator>) {
) -> EvalResult<'tcx, (PtrAndAlign, Ty<'tcx>)> {
debug!("eval_body: {:?}, {:?}", instance, param_env);
let limits = super::ResourceLimits::default();
let mut ecx = EvalContext::new(tcx, param_env, limits, CompileTimeEvaluator, ());
@ -33,55 +54,43 @@ pub fn eval_body<'a, 'tcx>(
promoted: None,
};
let try = (|| {
if ecx.tcx.has_attr(instance.def_id(), "linkage") {
return Err(ConstEvalError::NotConst("extern global".to_string()).into());
}
// FIXME(eddyb) use `Instance::ty` when it becomes available.
let instance_ty =
ecx.monomorphize(instance.def.def_ty(tcx), instance.substs);
if tcx.interpret_interner.borrow().get_cached(cid).is_none() {
let mir = ecx.load_mir(instance.def)?;
let layout = ecx.layout_of(instance_ty)?;
assert!(!layout.is_unsized());
let ptr = ecx.memory.allocate(
layout.size.bytes(),
layout.align.abi(),
None,
)?;
tcx.interpret_interner.borrow_mut().cache(
cid,
PtrAndAlign {
ptr: ptr.into(),
aligned: !layout.is_packed(),
},
);
let cleanup = StackPopCleanup::MarkStatic(Mutability::Immutable);
let name = ty::tls::with(|tcx| tcx.item_path_str(instance.def_id()));
trace!("const_eval: pushing stack frame for global: {}", name);
ecx.push_stack_frame(
instance,
mir.span,
mir,
Place::from_ptr(ptr),
cleanup.clone(),
)?;
if ecx.tcx.has_attr(instance.def_id(), "linkage") {
return Err(ConstEvalError::NotConst("extern global".to_string()).into());
}
// FIXME(eddyb) use `Instance::ty` when it becomes available.
let instance_ty =
ecx.monomorphize(instance.def.def_ty(tcx), instance.substs);
if tcx.interpret_interner.borrow().get_cached(cid).is_none() {
let mir = ecx.load_mir(instance.def)?;
let layout = ecx.layout_of(instance_ty)?;
assert!(!layout.is_unsized());
let ptr = ecx.memory.allocate(
layout.size.bytes(),
layout.align.abi(),
None,
)?;
tcx.interpret_interner.borrow_mut().cache(
cid,
PtrAndAlign {
ptr: ptr.into(),
aligned: !layout.is_packed(),
},
);
let cleanup = StackPopCleanup::MarkStatic(Mutability::Immutable);
let name = ty::tls::with(|tcx| tcx.item_path_str(instance.def_id()));
trace!("const_eval: pushing stack frame for global: {}", name);
ecx.push_stack_frame(
instance,
mir.span,
mir,
Place::from_ptr(ptr),
cleanup.clone(),
)?;
while ecx.step()? {}
// reinsert the stack frame so any future queries have the correct substs
ecx.push_stack_frame(
instance,
mir.span,
mir,
Place::from_ptr(ptr),
cleanup,
)?;
}
let value = tcx.interpret_interner.borrow().get_cached(cid).expect("global not cached");
Ok((value, instance_ty))
})();
(try, ecx)
while ecx.step()? {}
}
let value = tcx.interpret_interner.borrow().get_cached(cid).expect("global not cached");
Ok((value, instance_ty))
}
pub fn eval_body_as_integer<'a, 'tcx>(
@ -89,8 +98,9 @@ pub fn eval_body_as_integer<'a, 'tcx>(
param_env: ty::ParamEnv<'tcx>,
instance: Instance<'tcx>,
) -> EvalResult<'tcx, ConstInt> {
let (ptr_ty, ecx) = eval_body(tcx, instance, param_env);
let ptr_ty = eval_body(tcx, instance, param_env);
let (ptr, ty) = ptr_ty?;
let ecx = mk_eval_cx(tcx, instance, param_env)?;
let prim = match ecx.read_maybe_aligned(ptr.aligned, |ectx| ectx.try_read_value(ptr.ptr, ty))? {
Some(Value::ByVal(prim)) => prim.to_bytes()?,
_ => return err!(TypeNotPrimitive(ty)),
@ -340,20 +350,19 @@ pub fn const_eval_provider<'a, 'tcx>(
trace!("const eval instance: {:?}, {:?}", instance, key.param_env);
let miri_result = ::interpret::eval_body(tcx, instance, key.param_env);
match (miri_result, old_result) {
((Err(err), ecx), Ok(ok)) => {
(Err(err), Ok(ok)) => {
trace!("miri failed, ctfe returned {:?}", ok);
tcx.sess.span_warn(
tcx.def_span(key.value.0),
"miri failed to eval, while ctfe succeeded",
);
let ecx = mk_eval_cx(tcx, instance, key.param_env).unwrap();
let () = unwrap_miri(&ecx, Err(err));
Ok(ok)
},
((Ok(_), _), Err(err)) => {
Err(err)
},
((Err(_), _), Err(err)) => Err(err),
((Ok((miri_val, miri_ty)), mut ecx), Ok(ctfe)) => {
(_, Err(err)) => Err(err),
(Ok((miri_val, miri_ty)), Ok(ctfe)) => {
let mut ecx = mk_eval_cx(tcx, instance, key.param_env).unwrap();
check_ctfe_against_miri(&mut ecx, miri_val, miri_ty, ctfe.val);
Ok(ctfe)
}

2
src/tools/miri

@ -1 +1 @@
Subproject commit bde093fa140cbf95023482a94b92b0b16af4b521
Subproject commit 2671cf34a58b11f995add8402e75c1cd94ed051e