Skip to content

Add memory-related API coverage to the public API fuzzer #13441

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
May 21, 2026
+431 −0
Merged

Add memory-related API coverage to the public API fuzzer #13441

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
224 changes: 224 additions & 0 deletions crates/fuzzing/src/generators/api.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -68,6 +68,21 @@ struct Swarm {
table_ty: bool,
table_drop: bool,
get_table_export: bool,
memory_type_new: bool,
memory_type_drop: bool,
memory_new: bool,
memory_read: bool,
memory_write: bool,
memory_data: bool,
memory_data_mut: bool,
memory_grow: bool,
memory_data_size: bool,
memory_size: bool,
memory_page_size: bool,
memory_page_size_log2: bool,
memory_ty: bool,
memory_drop: bool,
get_memory_export: bool,
}

/// A call to one of Wasmtime's public APIs.
Expand Down Expand Up @@ -168,6 +183,62 @@ pub enum ApiCall {
instance: usize,
nth: usize,
},
MemoryTypeNew {
id: usize,
minimum: u32,
maximum: Option<u32>,
},
MemoryTypeDrop {
id: usize,
},
MemoryNew {
id: usize,
memory_ty: usize,
store: usize,
},
MemoryRead {
memory: usize,
offset: usize,
len: usize,
},
MemoryWrite {
memory: usize,
offset: usize,
data: Vec<u8>,
},
MemoryData {
memory: usize,
},
MemoryDataMut {
memory: usize,
},
MemoryGrow {
memory: usize,
delta: u32,
},
MemoryDataSize {
memory: usize,
},
MemorySize {
memory: usize,
},
MemoryPageSize {
memory: usize,
},
MemoryPageSizeLog2 {
memory: usize,
},
MemoryTy {
memory: usize,
},
MemoryDrop {
id: usize,
},
GetMemoryExport {
id: usize,
instance: usize,
nth: usize,
},
}
use ApiCall::*;

Expand Down Expand Up @@ -198,6 +269,13 @@ struct Scope {
/// associated `store_id`.
tables: BTreeMap<usize, usize>, // table_id -> store_id

/// Memory types that are currently live.
memory_types: BTreeSet<usize>,

/// Memories that are currently live. Maps from `memory_id` to the memory's
/// associated `store_id`.
memories: BTreeMap<usize, usize>, // memory_id -> store_id

config: Config,
}

Expand Down Expand Up @@ -233,6 +311,8 @@ impl<'a> Arbitrary<'a> for ApiCalls {
globals: BTreeMap::default(),
table_types: BTreeSet::default(),
tables: BTreeMap::default(),
memory_types: BTreeSet::default(),
memories: BTreeMap::default(),
config: config.clone(),
};

Expand Down Expand Up @@ -271,6 +351,7 @@ impl<'a> Arbitrary<'a> for ApiCalls {
scope.instances.retain(|_, store_id| *store_id != id);
scope.globals.retain(|_, store_id| *store_id != id);
scope.tables.retain(|_, store_id| *store_id != id);
scope.memories.retain(|_, store_id| *store_id != id);
Ok(StoreDrop { id })
});
}
Expand Down Expand Up @@ -480,6 +561,149 @@ impl<'a> Arbitrary<'a> for ApiCalls {
Ok(GetTableExport { id, instance, nth })
});
}
if swarm.memory_type_new {
choices.push(|input, scope| {
let id = scope.next_id();
let minimum = u32::arbitrary(input)? % 10;
let has_max = bool::arbitrary(input)?;
let maximum = if has_max {
Some(minimum + u32::arbitrary(input)? % 10)
} else {
None
};
scope.memory_types.insert(id);
Ok(MemoryTypeNew {
id,
minimum,
maximum,
})
});
}
if swarm.memory_type_drop && !scope.memory_types.is_empty() {
choices.push(|input, scope| {
let types: Vec<_> = scope.memory_types.iter().collect();
let id = **input.choose(&types)?;
scope.memory_types.remove(&id);
Ok(MemoryTypeDrop { id })
});
}
if swarm.memory_new && !scope.memory_types.is_empty() && !scope.stores.is_empty() {
choices.push(|input, scope| {
let types: Vec<_> = scope.memory_types.iter().collect();
let memory_ty = **input.choose(&types)?;
let stores: Vec<_> = scope.stores.iter().collect();
let store = **input.choose(&stores)?;
let id = scope.next_id();
scope.memories.insert(id, store);
Ok(MemoryNew {
id,
memory_ty,
store,
})
});
}
if swarm.memory_read && !scope.memories.is_empty() {
choices.push(|input, scope| {
let memories: Vec<_> = scope.memories.keys().collect();
let memory = **input.choose(&memories)?;
let offset = usize::arbitrary(input)?;
let len = usize::arbitrary(input)? % 64;
Ok(MemoryRead {
memory,
offset,
len,
})
});
}
if swarm.memory_write && !scope.memories.is_empty() {
choices.push(|input, scope| {
let memories: Vec<_> = scope.memories.keys().collect();
let memory = **input.choose(&memories)?;
let offset = usize::arbitrary(input)?;
let data = Vec::<u8>::arbitrary(input)?;
Ok(MemoryWrite {
memory,
offset,
data,
})
});
}
if swarm.memory_data && !scope.memories.is_empty() {
choices.push(|input, scope| {
let memories: Vec<_> = scope.memories.keys().collect();
let memory = **input.choose(&memories)?;
Ok(MemoryData { memory })
});
}
if swarm.memory_data_mut && !scope.memories.is_empty() {
choices.push(|input, scope| {
let memories: Vec<_> = scope.memories.keys().collect();
let memory = **input.choose(&memories)?;
Ok(MemoryDataMut { memory })
});
}
if swarm.memory_grow && !scope.memories.is_empty() {
choices.push(|input, scope| {
let memories: Vec<_> = scope.memories.keys().collect();
let memory = **input.choose(&memories)?;
let delta = u32::arbitrary(input)? % 10;
Ok(MemoryGrow { memory, delta })
});
}
if swarm.memory_data_size && !scope.memories.is_empty() {
choices.push(|input, scope| {
let memories: Vec<_> = scope.memories.keys().collect();
let memory = **input.choose(&memories)?;
Ok(MemoryDataSize { memory })
});
}
if swarm.memory_size && !scope.memories.is_empty() {
choices.push(|input, scope| {
let memories: Vec<_> = scope.memories.keys().collect();
let memory = **input.choose(&memories)?;
Ok(MemorySize { memory })
});
}
if swarm.memory_page_size && !scope.memories.is_empty() {
choices.push(|input, scope| {
let memories: Vec<_> = scope.memories.keys().collect();
let memory = **input.choose(&memories)?;
Ok(MemoryPageSize { memory })
});
}
if swarm.memory_page_size_log2 && !scope.memories.is_empty() {
choices.push(|input, scope| {
let memories: Vec<_> = scope.memories.keys().collect();
let memory = **input.choose(&memories)?;
Ok(MemoryPageSizeLog2 { memory })
});
}
if swarm.memory_ty && !scope.memories.is_empty() {
choices.push(|input, scope| {
let memories: Vec<_> = scope.memories.keys().collect();
let memory = **input.choose(&memories)?;
Ok(MemoryTy { memory })
});
}
if swarm.memory_drop && !scope.memories.is_empty() {
choices.push(|input, scope| {
let memories: Vec<_> = scope.memories.keys().collect();
let id = **input.choose(&memories)?;
scope.memories.remove(&id);
Ok(MemoryDrop { id })
});
}
if swarm.get_memory_export && !scope.instances.is_empty() {
choices.push(|input, scope| {
let instances: Vec<_> = scope.instances.keys().collect();
let instance = **input.choose(&instances)?;
let nth = usize::arbitrary(input)?;
let id = scope.next_id();
let store = *scope.instances.get(&instance).unwrap();
scope.memories.insert(id, store);
Ok(GetMemoryExport { id, instance, nth })
});
}

if choices.is_empty() {
break;
Expand Down
Loading
Loading