Skip to content

When popping in CTFE, perform validation before jumping to next statement to have a better span for the error #56022

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 2 commits into from
Nov 23, 2018
Merged

When popping in CTFE, perform validation before jumping to next statement to have a better span for the error #56022

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
1d808d1
When popping in CTFE, perform validation before jumping to next state…
RalfJung Nov 17, 2018
bcf82ef
deallocate locals before validation, to catch dangling references
RalfJung Nov 17, 2018
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
21 changes: 14 additions & 7 deletions src/librustc_mir/interpret/eval_context.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -492,15 +492,14 @@ impl<'a, 'mir, 'tcx: 'mir, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tc
let frame = self.stack.pop().expect(
"tried to pop a stack frame, but there were none",
);
// Abort early if we do not want to clean up: We also avoid validation in that case,
// because this is CTFE and the final value will be thoroughly validated anyway.
match frame.return_to_block {
StackPopCleanup::Goto(block) => {
self.goto_block(block)?;
}
StackPopCleanup::Goto(_) => {},
StackPopCleanup::None { cleanup } => {
if !cleanup {
// Leak the locals. Also skip validation, this is only used by
// static/const computation which does its own (stronger) final
// validation.
assert!(self.stack.is_empty(), "only the topmost frame should ever be leaked");
// Leak the locals, skip validation.
return Ok(());
}
}
Expand All @@ -509,7 +508,8 @@ impl<'a, 'mir, 'tcx: 'mir, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tc
for local in frame.locals {
self.deallocate_local(local)?;
}
// Validate the return value.
// Validate the return value. Do this after deallocating so that we catch dangling
// references.
if let Some(return_place) = frame.return_place {
if M::enforce_validity(self) {
// Data got changed, better make sure it matches the type!
Expand All @@ -530,6 +530,13 @@ impl<'a, 'mir, 'tcx: 'mir, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tc
// Uh, that shouldn't happen... the function did not intend to return
return err!(Unreachable);
}
// Jump to new block -- *after* validation so that the spans make more sense.
match frame.return_to_block {
StackPopCleanup::Goto(block) => {
self.goto_block(block)?;
}
StackPopCleanup::None { .. } => {}
}

if self.stack.len() > 1 { // FIXME should be "> 0", printing topmost frame crashes rustc...
debug!("CONTINUING({}) {}", self.cur_frame(), self.frame().instance);
Expand Down