Skip to content

interpret/memory: explain why we check is_thread_local_static #119257

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 1 commit into from
Dec 24, 2023
Merged

interpret/memory: explain why we check is_thread_local_static #119257

Changes from all commits
Commits
Show all changes
1 commit
Select commit
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
6 changes: 6 additions & 0 deletions compiler/rustc_const_eval/src/interpret/memory.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -165,6 +165,8 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
// We need to handle `extern static`.
match self.tcx.try_get_global_alloc(alloc_id) {
Some(GlobalAlloc::Static(def_id)) if self.tcx.is_thread_local_static(def_id) => {
// Thread-local statics do not have a constant address. They *must* be accessed via
// `ThreadLocalRef`; we can never have a pointer to them as a regular constant value.
bug!("global memory cannot point to thread-local static")
}
Some(GlobalAlloc::Static(def_id)) if self.tcx.is_foreign_item(def_id) => {
Expand Down Expand Up @@ -539,6 +541,8 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
None => throw_ub!(PointerUseAfterFree(id, CheckInAllocMsg::MemoryAccessTest)),
Some(GlobalAlloc::Static(def_id)) => {
assert!(self.tcx.is_static(def_id));
// Thread-local statics do not have a constant address. They *must* be accessed via
// `ThreadLocalRef`; we can never have a pointer to them as a regular constant value.
assert!(!self.tcx.is_thread_local_static(def_id));
// Notice that every static has two `AllocId` that will resolve to the same
// thing here: one maps to `GlobalAlloc::Static`, this is the "lazy" ID,
Expand Down Expand Up @@ -740,6 +744,8 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
match self.tcx.try_get_global_alloc(id) {
Some(GlobalAlloc::Static(def_id)) => {
assert!(self.tcx.is_static(def_id));
// Thread-local statics do not have a constant address. They *must* be accessed via
// `ThreadLocalRef`; we can never have a pointer to them as a regular constant value.
assert!(!self.tcx.is_thread_local_static(def_id));
// Use size and align of the type.
let ty = self
Expand Down