mikros/rust
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

clarify comment

Browse Source
This commit is contained in:
Ralf Jung 2023-10-19 22:32:42 +02:00
parent b325f31f66
commit ecaf828e13
1 changed files with 7 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
src/tools/miri/src/intptrcast.rs
View File

@ -275,9 +275,13 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
impl GlobalStateInner {
pub fn free_alloc_id(&mut self, dead_id: AllocId) {
// We can *not* remove this from `base_addr`, since `addr_from_alloc_id` is called on each
// attempt at a memory access to determine the allocation ID and offset -- and there can
// still be pointers with `dead_id` that one can attempt to use for a memory access.
// We can *not* remove this from `base_addr`, since the interpreter design requires that we
// be able to retrieve an AllocId + offset for any memory access *before* we check if the
// access is valid. Specifically, `ptr_get_alloc` is called on each attempt at a memory
// access to determine the allocation ID and offset -- and there can still be pointers with
// `dead_id` that one can attempt to use for a memory access. `ptr_get_alloc` may return
// `None` only if the pointer truly has no provenance (this ensures consistent error
// messages).
// However, we *can* remove it from `int_to_ptr_map`, since any wildcard pointers that exist
// can no longer actually be accessing that address. This ensures `alloc_id_from_addr` never
// returns a dead allocation.