* Update wasm-tools crates
This commit updates the wasm-tools family of crates as used in Wasmtime.
Notably this brings in the update which removes module linking support
as well as a number of internal refactorings around names and such
within wasmparser itself. This updates all of the wasm translation
support which binds to wasmparser as appropriate.
Other crates all had API-compatible changes for at least what Wasmtime
used so no further changes were necessary beyond updating version
requirements.
* Update a test expectation
Ended up being a routine update but seemed good to go ahead and hook up
updates. While I was at it I went ahead and hooked up multi-value
swarm fuzzing as well now that wasm-smith implements it.
This will make it generate `table.set`s that come from `global.get`s and
`global.get`s that come from `table.set`s. Ultimately, it should give us much
more fuzzing coverage of `externref` globals, their barriers, and passing
`externref`s into and out of Wasm to get or set globals.
We _must not_ trigger a GC when moving refs from host code into
Wasm (e.g. returned from a host function or passed as arguments to a Wasm
function). After insertion into the table, this reference is no longer
rooted. If multiple references are being sent from the host into Wasm and we
allowed GCs during insertion, then the following events could happen:
* Reference A is inserted into the activations table. This does not trigger a
GC, but does fill the table to capacity.
* The caller's reference to A is removed. Now the only reference to A is from
the activations table.
* Reference B is inserted into the activations table. Because the table is at
capacity, a GC is triggered.
* A is reclaimed because the only reference keeping it alive was the activation
table's reference (it isn't inside any Wasm frames on the stack yet, so stack
scanning and stack maps don't increment its reference count).
* We transfer control to Wasm, giving it A and B. Wasm uses A. That's a use
after free.
To prevent uses after free, we cannot GC when moving refs into the
`VMExternRefActivationsTable` because we are passing them from the host to Wasm.
On the other hand, when we are *cloning* -- as opposed to moving -- refs from
the host to Wasm, then it is fine to GC while inserting into the activations
table, because the original referent that we are cloning from is still alive and
rooting the ref.
* Enable simd fuzzing on oss-fuzz
This commit generally enables the simd feature while fuzzing, which
should affect almost all fuzzers. For fuzzers that just throw random
data at the wall and see what sticks, this means that they'll now be
able to throw simd-shaped data at the wall and have it stick. For
wasm-smith-based fuzzers this commit also updates wasm-smith to 0.6.0
which allows further configuring the `SwarmConfig` after generation,
notably allowing `instantiate-swarm` to generate modules using simd
using `wasm-smith`. This should much more reliably feed simd-related
things into the fuzzers.
Finally, this commit updates wasmtime to avoid usage of the general
`wasm_smith::Module` generator to instead use a Wasmtime-specific custom
default configuration which enables various features we have
implemented.
* Allow dummy table creation to fail
Tables might creation for imports may exceed the memory limit on the
store, which we'll want to gracefully recover from and not fail the
fuzzers.
* 2499: First pass on TableOps fuzzer generator wasm_encoder migration
- wasm binary generated via sections and smushed together into a module
- test: compare generated wat against expected wat
- note: doesn't work
- Grouped instructions not implemented
- Vec<u8> to wat String not implemented
* 2499: Add typesection, abstract instruction puts, and update test
- TableOp.insert now will interact with a function object directly
- add types for generated function
- expected test string now reflects expected generated code
* 2499: Mark unused index as _i
* 2499: Function insertion is in proper stack order, and fix off by 1
index
- imported functions must be typed
- instructions operate on a stack ie. define values as instructions
before using
* 2499: Apply suggestions from code review
- typo fixing
- oracle ingests binary bytes itself
Co-authored-by: Nick Fitzgerald <fitzgen@gmail.com>
* 2499: Code cleanup + renaming vars
- busywork, nothing to see here
Co-authored-by: Nick Fitzgerald <fitzgen@gmail.com>
This new fuzz target exercises sequences of `table.get`s, `table.set`s, and
GCs.
It already found a couple bugs:
* Some leaks due to ref count cycles between stores and host-defined functions
closing over those stores.
* If there are no live references for a PC, Cranelift can avoid emiting an
associated stack map. This was running afoul of a debug assertion.
