Skip to content

Further refine behavior of large 1-byte-page memories #12976

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
fitzgen merged 1 commit into from
Apr 6, 2026
+15 −16
Merged

Further refine behavior of large 1-byte-page memories #12976

Show file tree
Hide file tree
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
17 changes: 8 additions & 9 deletions crates/wasmtime/src/runtime/vm/memory.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -423,16 +423,15 @@ impl Memory {
});
match new_size {
Some(new_size) => {
// FIXME(WebAssembly/custom-page-sizes#45) - what should the
// behavior here be exactly? A trap? Return -1? A smaller limit?
// Unclear!
//
// Trap for now to make this as noisy/conservative as possible.
// Disallow growth to a value which this linear memory's type
// cannot represent. For example 1-byte-page memories cannot be
// 4GiB in size.
if !self.ty().allow_growth_to(new_size) {
bail!(
"disallowing growth to {new_size:#x} bytes based on \
page size"
)
if let Some(limiter) = limiter {
let err = crate::format_err!("memory growth exceeds memory type's limits");
limiter.memory_grow_failed(err)?;
}
return Ok(None);
}
}

Expand Down
8 changes: 4 additions & 4 deletions tests/misc_testsuite/custom-page-sizes/max-size-invalid.wast
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -26,8 +26,8 @@
memory.grow)
)

(assert_trap (invoke "grow" (i32.const 1)) "disallowing growth to 0xffffffff bytes based on page size")
(assert_trap (invoke "grow" (i32.const 2)) "disallowing growth to 0x100000000 bytes based on page size")
(assert_trap (invoke "grow" (i32.const 100)) "disallowing growth to 0x100000062 bytes based on page size")
(assert_trap (invoke "grow" (i32.const -1)) "disallowing growth to 0x1fffffffd bytes based on page size")
(assert_return (invoke "grow" (i32.const 1)) (i32.const -1))
(assert_return (invoke "grow" (i32.const 2)) (i32.const -1))
(assert_return (invoke "grow" (i32.const 100)) (i32.const -1))
(assert_return (invoke "grow" (i32.const -1)) (i32.const -1))
(assert_return (invoke "grow" (i32.const 0)) (i32.const -2))
6 changes: 3 additions & 3 deletions tests/misc_testsuite/memory-combos.wast
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -127,7 +127,7 @@
(assert_trap (invoke "store_m3" (i32.const -1) (i32.const 0)) "out of bounds memory access")
(assert_return (invoke "grow_m3" (i32.const 1)) (i32.const 1))
(assert_return (invoke "size_m3") (i32.const 2))
(assert_trap (invoke "grow_m3" (i32.const -1)) "disallowing growth")
(assert_return (invoke "grow_m3" (i32.const -1)) (i32.const -1))
(assert_return (invoke "load_m3" (i32.const 1)) (i32.const 0))
(assert_return (invoke "store_m3" (i32.const 1) (i32.const 1)))
(assert_return (invoke "load_m3" (i32.const 1)) (i32.const 1))
Expand All @@ -144,7 +144,7 @@
(assert_trap (invoke "store_m4" (i32.const -1) (i32.const 0)) "out of bounds memory access")
(assert_return (invoke "grow_m4" (i32.const 1)) (i32.const 1))
(assert_return (invoke "size_m4") (i32.const 2))
(assert_trap (invoke "grow_m4" (i32.const -1)) "disallowing growth")
(assert_return (invoke "grow_m4" (i32.const -1)) (i32.const -1))
(assert_return (invoke "load_m4" (i32.const 1)) (i32.const 0))
(assert_return (invoke "store_m4" (i32.const 1) (i32.const 1)))
(assert_return (invoke "load_m4" (i32.const 1)) (i32.const 1))
Expand Down Expand Up @@ -178,7 +178,7 @@
(assert_trap (invoke "store_m8" (i32.const -1) (i32.const 0)) "out of bounds memory access")
(assert_return (invoke "grow_m8" (i32.const 1)) (i32.const 1))
(assert_return (invoke "size_m8") (i32.const 2))
(assert_trap (invoke "grow_m8" (i32.const -1)) "disallowing growth")
(assert_return (invoke "grow_m8" (i32.const -1)) (i32.const -1))
(assert_return (invoke "load_m8" (i32.const 1)) (i32.const 0))
(assert_return (invoke "store_m8" (i32.const 1) (i32.const 1)))
(assert_return (invoke "load_m8" (i32.const 1)) (i32.const 1))
Expand Down
Loading