Minor thing I noticed from #4990 but I stylistically prefer to keep the
`mod foo;` definitions canonicalized to one location to emphasize how
multiple targets can use the same definition.
* Make wasmtime build for windows-aarch64
* Add check for win arm64 build.
* Fix checks for winarm64 key in workflows.
* Add target in windows arm64 build.
* Add tracking issue for Windows ARM64 trap handling
* Update spec test repo
Our submodule was accidentally reverted to an older commit as part
of #4271 and while it could be updated to as it was before I went ahead
and updated it to `main`.
* Update ignore directives and test multi-memory
* Update riscv ignores
* Update wasm-tools dependencies
This update brings in a number of features such as:
* The component model binary format and AST has been slightly adjusted
in a few locations. Names are dropped from parameters/results now in
the internal representation since they were not used anyway. At this
time the ability to bind a multi-return function has not been exposed.
* The `wasmparser` validator pass will now share allocations with prior
functions, providing what's probably a very minor speedup for Wasmtime
itself.
* The text format for many component-related tests now requires named
parameters.
* Some new relaxed-simd instructions are updated to be ignored.
I hope to have a follow-up to expose the multi-return ability to the
embedding API of components.
* Update audit information for new crates
This commit updates the `MIN_STACK_SIZE` constant for Unix platforms
when allocating a sigaltstack from 16k to 64k. The signal handler
captures a wasm `Backtrace` which involves memory allocations and it was
recently discovered that, at least in debug mode, jemalloc can take up
to 16k of stack space for an allocation. To allow running the
sigaltstack size is increased here.
This historically was used to guard against recursive faults but
later refactorings have made this variable somewhat obsolete. The code
that it still protects is not the "meat" of trap handling. Instead the
`jmp_buf_if_trap` is changed to be more like "take" so once a "take"
succeeds it won't be able to recursively call any more "meat".
Overall this shouldn't affect anything, it's just a small internal
cleanup.
* Leverage Cargo's workspace inheritance feature
This commit is an attempt to reduce the complexity of the Cargo
manifests in this repository with Cargo's workspace-inheritance feature
becoming stable in Rust 1.64.0. This feature allows specifying fields in
the root workspace `Cargo.toml` which are then reused throughout the
workspace. For example this PR shares definitions such as:
* All of the Wasmtime-family of crates now use `version.workspace =
true` to have a single location which defines the version number.
* All crates use `edition.workspace = true` to have one default edition
for the entire workspace.
* Common dependencies are listed in `[workspace.dependencies]` to avoid
typing the same version number in a lot of different places (e.g. the
`wasmparser = "0.89.0"` is now in just one spot.
Currently the workspace-inheritance feature doesn't allow having two
different versions to inherit, so all of the Cranelift-family of crates
still manually specify their version. The inter-crate dependencies,
however, are shared amongst the root workspace.
This feature can be seen as a method of "preprocessing" of sorts for
Cargo manifests. This will help us develop Wasmtime but shouldn't have
any actual impact on the published artifacts -- everything's dependency
lists are still the same.
* Fix wasi-crypto tests
This fixes a compile-time error introduced in #4207. The `?` operator
doesn't work inside `Option::map` because it tries to return from the
inner closure, not the outer function.
Apparently our CI doesn't build wasmtime-bench-api so it didn't catch
this issue.
`tracing` crate is already used within the codebase, this change allows
developers to benefit from that functionality when running and debugging
tests
Signed-off-by: Roman Volosatovs <rvolosatovs@riseup.net>
Signed-off-by: Roman Volosatovs <rvolosatovs@riseup.net>
* bench-api: configure WASI modules based on passed flags
When benchmarking in Sightglass, @brianjjones has found it necessary to
enable the wasi-nn module. The current way to do so is to alter the
engine build script to pass `--features wasi-nn` so that this crate can
run code relying on these imports. This change allows the user to
instead pass the WASI modules using the engine flags added in #4096.
This could look something like the following in Sightglass:
```
sightglass-cli benchmark ... --engine-flags '--wasi-modules experimental-wasi-nn'
```
* fix: disable wasi-crypto as a default feature
* Update to cap-std 0.26.
This is primarily to pull in bytecodealliance/cap-std#271, the fix for #4936,
compilation on Rust nightly on Windows.
It also updates to rustix 0.35.10, to pull in bytecodealliance/rustix#403,
the fix for bytecodealliance/rustix#402, compilation on newer versions of
the libc crate, which changed a public function from `unsafe` to safe.
Fixes#4936.
* Update the system-interface audit for 0.23.
* Update the libc supply-chain config version.
This commit limits the maximum number of linear memories when the
pooling allocator is used to ensure that the virtual memory mapping for
the pooling allocator itself can succeed. Currently there are a number
of crashes in the differential fuzzer where the pooling allocator can't
allocate its mapping because the maximum specified number of linear
memories times the number of instances exceeds the address space
presumably.
* Optimize the WASI `random_get` implementation.
Use `StdRng` instead of the `OsRng` in the default implementation of
`random_get`. This uses a userspace CSPRNG, making `random_get` 3x faster
in simple benchmarks.
* Update cargo-vet audits for cap-std 0.25.3.
* Update all cap-std packages to 0.25.3.
* fuzz: improve the API of the `wasm-spec-interpreter` crate
This change addresses key parts of #4852 by improving the bindings to
the OCaml spec interpreter. The new API allows users to `instantiate` a
module, `interpret` named functions on that instance, and `export`
globals and memories from that instance. This currently leaves the
existing implementation ("instantiate and interpret the first function in
a module") present under a new name: `interpret_legacy`.
* fuzz: adapt the differential spec engine to the new API
This removes the legacy uses in the differential spec engine, replacing
them with the new `instantiate`-`interpret`-`export` API from the
`wasm-spec-interpreter` crate.
* fix: make instance access thread-safe
This changes the OCaml-side definition of the instance so that each
instance carries round a reference to a "global store" that's specific
to that instantiation. Because everything is updated by reference there
should be no visible behavioural change on the Rust side, apart from
everything suddenly being thread-safe (modulo the fact that access to
the OCaml runtime still needs to be locked). This fix will need to be
generalised slightly in future if we want to allow multiple modules to
be instantiated in the same store.
Co-authored-by: conrad-watt <cnrdwtt@gmail.com>
Co-authored-by: Alex Crichton <alex@alexcrichton.com>
* Initial forward-edge CFI implementation
Give the user the option to start all basic blocks that are targets
of indirect branches with the BTI instruction introduced by the
Branch Target Identification extension to the Arm instruction set
architecture.
Copyright (c) 2022, Arm Limited.
* Refactor `from_artifacts` to avoid second `make_executable` (#1)
This involves "parsing" twice but this is parsing just the header of an
ELF file so it's not a very intensive operation and should be ok to do
twice.
* Address the code review feedback
Copyright (c) 2022, Arm Limited.
Co-authored-by: Alex Crichton <alex@alexcrichton.com>
* [fuzz] Add SIMD to single-instruction generator
This change extends the single-instruction generator with most of the
SIMD instructions. Examples of instructions that were excluded are: all
memory-related instructions, any instruction with an immediate.
* [fuzz] Generate V128s with known values from each type
To better cover the fuzzing search space, `DiffValue` will generate
better known values for the `V128` type. First, it uses arbitrary data
to select a sub-type (e.g., `I8x16`, `F32x4`, etc.) and then it fills in
the bytes by generating biased values for each of the lanes.
* [fuzz] Canonicalize NaN values in SIMD lanes
This change ports the NaN canonicalization logic from `wasm-smith`
([here]) to the single-instruction generator.
[here]: https://github.com/bytecodealliance/wasm-tools/blob/6c127a6/crates/wasm-smith/src/core/code_builder.rs#L927
This commit replaces #4869 and represents the actual version bump that
should have happened had I remembered to bump the in-tree version of
Wasmtime to 1.0.0 prior to the branch-cut date. Alas!
This commit hard-codes the pooling allocator's limit of linear memories
to 1 when used with fuzzing the spec tests themselves. This prevents the
number from being set too high and hitting a virtual-memory-based OOM
due to the virtual memory reservation of the pooling allocator being too
large.
* Throw out fewer fuzz inputs with differential fuzzer
Prior to this commit the differential fuzzer would generate a module and
then select an engine to execute the module against Wasmtime. This
meant, however, that the candidate list of engines were filtered against
the configuration used to generate the module to ensure that the
selected engine could run the generated module.
This commit inverts this logic and instead selects an engine first,
allowing the engine to then tweak the module configuration to ensure
that the generated module is compatible with the engine selected. This
means that fewer fuzz inputs are discarded because every fuzz input will
result in an engine being executed.
Internally the engine constructors have all been updated to update the
configuration to work instead of filtering the configuration. Some other
fixes were applied for the spec interpreter as well to work around #4852
* Fix tests
* Improve wasmi differential fuzzer
* Support modules with a `start` function
* Implement trap-matching to ensure that wasmi and Wasmtime both report
the same flavor of trap.
* Support differential fuzzing where no engines match
Locally I was attempting to run against just one wasm engine with
`ALLOWED_ENGINES=wasmi` but the fuzzer quickly panicked because the
generated test case didn't match wasmi's configuration. This commit
updates engine-selection in the differential fuzzer to return `None` if
no engine is applicable, throwing out the test case. This won't be hit
at all with oss-fuzz-based runs but for local runs it'll be useful to
have.
* Improve proposal support in differential fuzzer
* De-prioritize unstable wasm proposals such as multi-memory and
memory64 by making them more unlikely with `Unstructured::ratio`.
* Allow fuzzing multi-table (reference types) and multi-memory by
avoiding setting their maximums to 1 in `set_differential_config`.
* Update selection of the pooling strategy to unconditionally support
the selected module config rather than the other way around.
* Improve handling of traps in differential fuzzing
This commit fixes an issue found via local fuzzing where engines were
reporting different results but the underlying reason for this was that
one engine was hitting stack overflow before the other. To fix the
underlying issue I updated the execution to check for stack overflow
and, if hit, it discards the entire fuzz test case from then on.
The rationale behind this is that each engine can have unique limits for
stack overflow. One test case I was looking at for example would stack
overflow at less than 1000 frames with epoch interruption enabled but
would stack overflow at more than 1000 frames with it disabled. This
means that the state after the trap started to diverge and it looked
like the engines produced different results.
While I was at it I also improved the "function call returned a trap"
case to compare traps to make sure the same trap reason popped out.
* Fix fuzzer tests
I noticed an oss-fuzz-based timeout that was reported for the
`component_api` fuzzer where the adapter module generated takes 1.5
seconds to compile the singular function in release mode (no fuzzing
enabled). The test case in question was a deeply recursive
list-of-list-of-etc and only one function was generated instead of
multiple. I updated the cost of strings/lists to cost more in the
approximate cost calculation which now forces the one giant function to
get split up and the large function is now split up into multiple
smaller function that take milliseconds to compile.
Add a function_alignment function to the TargetIsa trait, and use it to align functions when generating objects. Additionally, collect the maximum alignment required for pc-relative constants in functions and pass that value out. Use the max of these two values when padding functions for alignment.
This fixes a bug on x86_64 where rip-relative loads to sse registers could cause a segfault, as functions weren't always guaranteed to be aligned to 16-byte addresses.
Fixes#4812
* components: Limit the recursive size of types in Wasmtime
This commit is aimed at fixing #4814 by placing a hard limit on the
maximal recursive depth a type may have in the component model. The
component model theoretically allows for infinite recursion but many
various types of operations within the component model are naturally
written as recursion over the structure of a type which can lead to
stack overflow with deeply recursive types. Some examples of recursive
operations are:
* Lifting and lowering a type - currently the recursion here is modeled
in Rust directly with `#[derive]` implementations as well as the
implementations for the `Val` type.
* Compilation of adapter trampolines which iterates over the type
structure recursively.
* Historically many various calculations like the size of a type, the
flattened representation of a type, etc, were all done recursively.
Many of these are more efficiently done via other means but it was
still natural to implement these recursively initially.
By placing a hard limit on type recursion Wasmtime won't be able to load
some otherwise-valid modules. The hope, though, is that no human-written
program is likely to ever reach this limit. This limit can be revised
and/or the locations with recursion revised if it's ever reached.
The implementation of this feature is done by generalizing the current
flattened-representation calculation which now keeps track of a type's
depth and size. The size calculation isn't used just yet but I plan to
use it in fixing #4816 and it was natural enough to write here as well.
The depth is checked after a type is translated and if it exceeds the
maximum then an error is returned.
Additionally the `Arbitrary for Type` implementation was updated to
prevent generation of a type that's too-recursive.
Closes#4814
* Remove unused size calculation
* Bump up just under the limit
This commit is a (second?) attempt at improving the generation of
adapter modules to avoid excessively large functions for fuzz-generated
inputs.
The first iteration of adapters simply translated an entire type
inline per-function. This proved problematic however since the size of
the adapter function was on the order of the overall size of a type,
which can be exponential for a type that is otherwise defined in linear
size.
The second iteration of adapters performed a split where memory-based
types would always be translated with individual functions. The theory
here was that once a type was memory-based it was large enough to not
warrant inline translation in the original function and a separate
outlined function could be shared and otherwise used to deduplicate
portions of the original giant function. This again proved problematic,
however, since the splitting heuristic was quite naive and didn't take
into account large stack-based types.
This third iteration in this commit replaces the previous system with a
similar but slightly more general one. Each adapter function now has a
concept of fuel which is decremented each time a layer of a type is
translated. When fuel runs out further translations are deferred to
outlined functions. The fuel counter should hopefully provide a sort of
reasonable upper bound on the size of a function and the outlined
functions should ideally provide the ability to be called from multiple
places and therefore deduplicate what would otherwise be a massive
function.
This final iteration is another attempt at guaranteeing that an adapter
module is linear in size with respect to the input type section of the
original module. Additionally this iteration uniformly handles stack and
memory-based translations which means that stack-based translations
can't go wild in their function size and memory-based translations may
benefit slightly from having at least a little bit of inlining
internally.
The immediate impact of this is that the `component_api` fuzzer seems to
be running at a faster rate than before. Otherwise #4825 is sufficient
to invalidate preexisting fuzz-bugs and this PR is hopefully the final
nail in the coffin to prevent further timeouts for small inputs cropping
up.
Closes#4816
We were previously implicitly assuming that all Wasm frames in a stack used the
same `VMRuntimeLimits` as the previous frame we walked, but this is not true
when Wasm in store A calls into the host which then calls into Wasm in store B:
| ... |
| Host | |
+-----------------+ | stack
| Wasm in store A | | grows
+-----------------+ | down
| Host | |
+-----------------+ |
| Wasm in store B | V
+-----------------+
Trying to walk this stack would previously result in a runtime panic.
The solution is to push the maintenance of our list of saved Wasm FP/SP/PC
registers that allow us to identify contiguous regions of Wasm frames on the
stack deeper into `CallThreadState`. The saved registers list is now maintained
whenever updating the `CallThreadState` linked list by making the
`CallThreadState::prev` field private and only accessible via a getter and
setter, where the setter always maintains our invariants.
* Add android aarch64 support into c-api
* Remove target test and clean up CMake script c-api
* Deduplicate ExternalProject_Add in c-api Android support
The version of the `arbitrary` crate used in fuzz targets needs to be
the same as the version used in `libfuzzer-sys`. That's why the latter
crate re-exports the former.
But we need to make sure to consistently use the re-exported version.
That's most easily done if that's the only version we have available.
However, `fuzz/Cargo.toml` declared a direct dependency on `arbitrary`,
making it available for import, and leading to that version being used
in a couple places.
There were two copies of `arbitrary` built before, even though they were
the same version: one with the `derive` feature turned on, through the
direct dependency, and one with it turned off when imported through
`libfuzzer-sys`. So I haven't specifically tested this but fuzzer builds
might be slightly faster now.
I have not removed the build-dep on `arbitrary`, because `build.rs` is
not invoked by libFuzzer and so it doesn't matter what version of
`arbitrary` it uses.
Our other crates, like `cranelift-fuzzgen` and `wasmtime-fuzzing`, can
still accidentally use a different version of `arbitrary` than the fuzz
targets which rely on them. This commit only fixes the direct cases
within `fuzz/**`.
* Implement the remaining socket-related WASI functions.
The original WASI specification included `sock_read`, `sock_write`, and
`shutdown`. Now that we have some sockets support, implement these
additional functions, to make it easier for people porting existing code
to WASI.
It's expected that this will all be subsumed by the wasi-sockets
proposal, but for now, this is a relatively small change which should
hopefully unblock people trying to use the current `accept` support.
* Update to system-interface 0.22, which has fixes for Windows.
* Make wasi-common-std-sync's dependency on system-interface private.
Change some `pub` functions which exposed system-interface types to be
non-`pub`.
And, change `from_sysif_fdflags` functions to `get_fd_flags` functions
that take `impl AsFilelike` arguments instead of system-interface types.
With these changes, system-interface is no longer exposed in the
public API.
* Add a public API for `is_read_write` too.
Implementors using types implementing `AsFilelike` may want to use the
same `is_read_write` logic, without explicitly depending on
system-interface, so provide a function that provides that.
POSIX specifies that functions like `nanosleep` use the REALTIME clock,
so allow WASI `poll_oneoff` calls to use the REALTIME clock, at least
for non-absolute intervals. POSIX specifies that the timeouts should not
be affected by subsequent `clock_settime` calls, so they behave the same
way as MONOTONIC clock requests, so we can implement them as monotonic
requests.
This change is a follow-on from #4515 to add the ability to configure
the `differential` fuzz target by limiting which engines and modules are
used for fuzzing. This is incredibly useful when troubleshooting, e.g.,
when an engine is more prone to failure, we can target that engine
exclusively. The effect of this configuration is visible in the
statistics now printed out from #4739.
Engines are configured using the `ALLOWED_ENGINES` environment variable.
We can either subtract from the set of allowed engines (e.g.,
`ALLOWED_ENGINES=-v8`) or build up a set of allowed engines (e.g.,
`ALLOWED_ENGINES=wasmi,spec`), but not both at the same time.
`ALLOWED_ENGINES` only configures the left-hand side engine; the
right-hand side is always Wasmtime. When omitted, `ALLOWED_ENGINES`
defaults to [`wasmtime`, `wasmi`, `spec`, `v8`].
The generated WebAssembly modules are configured using
`ALLOWED_MODULES`. This environment variables works the same as above
but the available options are: [`wasm-smith`, `single-inst`].
* Port v8 fuzzer to the new framework
This commit aims to improve the support for the new "meta" differential
fuzzer added in #4515 by ensuring that all existing differential fuzzing
is migrated to this new fuzzer. This PR includes features such as:
* The V8 differential execution is migrated to the new framework.
* `Config::set_differential_config` no longer force-disables wasm
features, instead allowing them to be enabled as per the fuzz input.
* `DiffInstance::{hash, hash}` was replaced with
`DiffInstance::get_{memory,global}` to allow more fine-grained
assertions.
* Support for `FuncRef` and `ExternRef` have been added to `DiffValue`
and `DiffValueType`. For now though generating an arbitrary
`ExternRef` and `FuncRef` simply generates a null value.
* Arbitrary `DiffValue::{F32,F64}` values are guaranteed to use
canonical NaN representations to fix an issue with v8 where with the
v8 engine we can't communicate non-canonical NaN values through JS.
* `DiffEngine::evaluate` allows "successful failure" for cases where
engines can't support that particular invocation, for example v8 can't
support `v128` arguments or return values.
* Smoke tests were added for each engine to ensure that a simple wasm
module works at PR-time.
* Statistics printed from the main fuzzer now include percentage-rates
for chosen engines as well as percentage rates for styles-of-module.
There's also a few small refactorings here and there but mostly just
things I saw along the way.
* Update the fuzzing README
* [fuzz] Remove the `differential` fuzz target
This functionality is already covered by the `differential_meta` target.
* [fuzz] Rename `differential_meta` to `differential`
Now that the `differential_meta` fuzz target does everything that the
existing `differential` target did and more, it can take over the
original name.
* [fuzz] Remove some differential fuzz targets
The changes in #4515 do everything the `differential_spec` and
`differential_wasmi` fuzz target already do. These fuzz targets are now
redundant and this PR removes them. It also updates the fuzz
documentation slightly.
* [fuzz] Add `Module` enum, refactor `ModuleConfig`
This change adds a way to create either a single-instruction module or a
regular (big) `wasm-smith` module. It has some slight refactorings in
preparation for the use of this new code.
* [fuzz] Add `DiffValue` for differential evaluation
In order to evaluate functions with randomly-generated values, we needed
a common way to generate these values. Using the Wasmtime `Val` type is
not great because we would like to be able to implement various traits
on the new value type, e.g., to convert `Into` and `From` boxed values
of other engines we differentially fuzz against. This new type,
`DiffValue`, gives us a common ground for all the conversions and
comparisons between the other engine types.
* [fuzz] Add interface for differential engines
In order to randomly choose an engine to fuzz against, we expect all of
the engines to meet a common interface. The traits in this commit allow
us to instantiate a module from its binary form, evaluate exported
functions, and (possibly) hash the exported items of the instance.
This change has some missing pieces, though:
- the `wasm-spec-interpreter` needs some work to be able to create
instances, evaluate a function by name, and expose exported items
- the `v8` engine is not implemented yet due to the complexity of its
Rust lifetimes
* [fuzz] Use `ModuleFeatures` instead of existing configuration
When attempting to use both wasm-smith and single-instruction modules,
there is a mismatch in how we communicate what an engine must be able to
support. In the first case, we could use the `ModuleConfig`, a wrapper
for wasm-smith's `SwarmConfig`, but single-instruction modules do not
have a `SwarmConfig`--the many options simply don't apply. Here, we
instead add `ModuleFeatures` and adapt a `ModuleConfig` to that.
`ModuleFeatures` then becomes the way to communicate what features an
engine must support to evaluate functions in a module.
* [fuzz] Add a new fuzz target using the meta-differential oracle
This change adds the `differential_meta` target to the list of fuzz
targets. I expect that sometime soon this could replace the other
`differential*` targets, as it almost checks all the things those check.
The major missing piece is that currently it only chooses
single-instruction modules instead of also generating arbitrary modules
using `wasm-smith`.
Also, this change adds the concept of an ignorable error: some
differential engines will choke with certain inputs (e.g., `wasmi` might
have an old opcode mapping) which we do not want to flag as fuzz bugs.
Here we wrap those errors in `DiffIgnoreError` and then use a new helper
trait, `DiffIgnorable`, to downcast and inspect the `anyhow` error to
only panic on non-ignorable errors; the ignorable errors are converted
to one of the `arbitrary::Error` variants, which we already ignore.
* [fuzz] Compare `DiffValue` NaNs more leniently
Because arithmetic NaNs can contain arbitrary payload bits, checking
that two differential executions should produce the same result should
relax the comparison of the `F32` and `F64` types (and eventually `V128`
as well... TODO). This change adds several considerations, however, so
that in the future we make the comparison a bit stricter, e.g., re:
canonical NaNs. This change, however, just matches the current logic
used by other fuzz targets.
* review: allow hashing mutate the instance state
@alexcrichton requested that the interface be adapted to accommodate
Wasmtime's API, in which even reading from an instance could trigger
mutation of the store.
* review: refactor where configurations are made compatible
See @alexcrichton's
[suggestion](https://github.com/bytecodealliance/wasmtime/pull/4515#discussion_r928974376).
* review: convert `DiffValueType` using `TryFrom`
See @alexcrichton's
[comment](https://github.com/bytecodealliance/wasmtime/pull/4515#discussion_r928962394).
* review: adapt target implementation to Wasmtime-specific RHS
This change is joint work with @alexcrichton to adapt the structure of
the fuzz target to his comments
[here](https://github.com/bytecodealliance/wasmtime/pull/4515#pullrequestreview-1073247791).
This change:
- removes `ModuleFeatures` and the `Module` enum (for big and small
modules)
- upgrades `SingleInstModule` to filter out cases that are not valid for
a given `ModuleConfig`
- adds `DiffEngine::name()`
- constructs each `DiffEngine` using a `ModuleConfig`, eliminating
`DiffIgnoreError` completely
- prints an execution rate to the `differential_meta` target
Still TODO:
- `get_exported_function_signatures` could be re-written in terms of the
Wasmtime API instead `wasmparser`
- the fuzzer crashes eventually, we think due to the signal handler
interference between OCaml and Wasmtime
- the spec interpreter has several cases that we skip for now but could
be fuzzed with further work
Co-authored-by: Alex Crichton <alex@alexcrichton.com>
* fix: avoid SIGSEGV by explicitly initializing OCaml runtime first
* review: use Wasmtime's API to retrieve exported functions
Co-authored-by: Alex Crichton <alex@alexcrichton.com>
Also, adjust the tests that are executed on that platform. Finally,
fix a bug with obtaining backtraces when back-edge CFI is enabled.
Copyright (c) 2022, Arm Limited.
* Upgrade wasm-tools crates, namely the component model
This commit pulls in the latest versions of all of the `wasm-tools`
family of crates. There were two major changes that happened in
`wasm-tools` in the meantime:
* bytecodealliance/wasm-tools#697 - this commit introduced a new API for
more efficiently reading binary operators from a wasm binary. The old
`Operator`-based reading was left in place, however, and continues to
be what Wasmtime uses. I hope to update Wasmtime in a future PR to use
this new API, but for now the biggest change is...
* bytecodealliance/wasm-tools#703 - this commit was a major update to
the component model AST. This commit almost entirely deals with the
fallout of this change.
The changes made to the component model were:
1. The `unit` type no longer exists. This was generally a simple change
where the `Unit` case in a few different locations were all removed.
2. The `expected` type was renamed to `result`. This similarly was
relatively lightweight and mostly just a renaming on the surface. I
took this opportunity to rename `val::Result` to `val::ResultVal` and
`types::Result` to `types::ResultType` to avoid clashing with the
standard library types. The `Option`-based types were handled with
this as well.
3. The payload type of `variant` and `result` types are now optional.
This affected many locations that calculate flat type
representations, ABI information, etc. The `#[derive(ComponentType)]`
macro now specifically handles Rust-defined `enum` types which have
no payload to the equivalent in the component model.
4. Functions can now return multiple parameters. This changed the
signature of invoking component functions because the return value is
now bound by `ComponentNamedList` (renamed from `ComponentParams`).
This had a large effect in the tests, fuzz test case generation, etc.
5. Function types with 2-or-more parameters/results must uniquely name
all parameters/results. This mostly affected the text format used
throughout the tests.
I haven't added specifically new tests for multi-return but I changed a
number of tests to use it. Additionally I've updated the fuzzers to all
exercise multi-return as well so I think we should get some good
coverage with that.
* Update version numbers
* Use crates.io
* Limit the size of functions in the `stacks` fuzzer
The fuzzers recently found a timeout in this fuzz test case related to
the compile time of the generated module. Inspecting the generated
module showed that it had 100k+ opcodes for one function, so this commit
updates the fuzzer to limit the number of operations per-function to a
smaller amount to avoid timeout limits.
* Use `arbitrary_len` for `ops` length
* Fix a max/min flip
* Fix a compile error on nightly Rust
It looks like Rust nightly has gotten a bit more strict about
attributes-on-expressions and previously accepted code is no longer
accepted. This commit updates the generated code for a macro to a form
which is accepted by rustc.
* Fix a soundness issue with lowering variants
This commit fixes a soundness issue lowering variants in the component
model where host memory could be leaked to the guest module by accident.
In reviewing code recently for `Val::lower` I noticed that the variant
lowering was extending the payload with `ValRaw::u32(0)` to
appropriately fit the size of the variant. In reading this it appeared
incorrect to me due to the fact that it should be `ValRaw::u64(0)` since
up to 64-bits can be read. Additionally this implementation was also
incorrect because the lowered representation of the payload itself was
not possibly zero-extended to 64-bits to accommodate other variants.
It turned out these issues were benign because with the dynamic
surface area to the component model the arguments were all initialized
to 0 anyway. The static version of the API, however, does not initialize
arguments to 0 and I wanted to initially align these two implementations
so I updated the variant implementation of lowering for dynamic values
and removed the zero-ing of arguments.
To test this change I updated the `debug` mode of adapter module
generation to assert that the upper bits of values in wasm are always
zero when the value is casted down (during `stack_get` which only
happens with variants). I then threaded through the `debug` boolean
configuration parameter into the dynamic and static fuzzers.
To my surprise this new assertion tripped even after the fix was
applied. It turns out, though, that there was other leakage of bits
through other means that I was previously unaware of. At the primitive
level lowerings of types like `u32` will have a `Lower` representation
of `ValRaw` and the lowering is simply `dst.write(ValRaw::i32(self))`,
or the equivalent thereof. The problem, that the fuzzers detected, with
this pattern is that the `ValRaw` type is 16-bytes, and
`ValRaw::i32(X)` only initializes the first 4. This meant that all the
lowerings for all primitives were writing up to 12 bytes of garbage from
the host for the wasm module to read.
It turned out that this write of a `ValRaw` was sometimes 16 bytes and
sometimes the appropriate size depending on the number of optimizations
in play. With enough inlining for example `dst.write(ValRaw::i32(self))`
would only write 4 bytes, as expected. In debug mode though without
inlining 16 bytes would be written, including the garbage from the upper
bits.
To solve this issue I ended up taking a somewhat different approach. I
primarily updated the `ValRaw` constructors to simply always extend the
values internally to 64-bits, meaning that the low 8 bytes of a `ValRaw`
is always initialized. This prevents any undefined data from leaking
from the host into a wasm module, and means that values are also
zero-extended even if they're only used in 32-bit contexts outside of a
variant. This felt like the best fix for now, though, in terms of
not really having a performance impact while additionally not requiring
a rewrite of all lowerings.
This solution ended up also neatly removing the "zero out the entire
payload" logic that was previously require. Now after a payload is
lowered only the tail end of the payload, up to the size of the variant,
is zeroed out. This means that each lowered argument is written to at
most once which should hopefully be a small performance boost for
calling into functions as well.
It looks like Rust nightly has gotten a bit more strict about
attributes-on-expressions and previously accepted code is no longer
accepted. This commit updates the generated code for a macro to a form
which is accepted by rustc.
* Optimize flat type representation calculations
Previously calculating the flat type representation would be done
recursively for an entire type tree every time it was visited.
Additionally the flat type representation was entirely built only to be
thrown away if it was too large at the end. This chiefly presented a
source of recursion based on the type structure in the component model
which fuzzing does not like as it reports stack overflows.
This commit overhauls the representation of flat types in Wasmtime by
caching the representation for each type in the compile-time
`ComponentTypesBuilder` structure. This avoids recalculating each time
the flat representation is queried and additionally allows opportunity
to have more short-circuiting to avoid building overly-large vectors.
* Remove duplicate flat count calculation in wasmtime
Roughly share the infrastructure in the `wasmtime-environ` crate, namely
the non-recursive and memoizing nature of the calculation.
* Fix component fuzz build
* Fix example compile
A `GtU` condition needed to actually be `GeU`, as the comment right
above it stated but apparently I forgot to translate the comment to
actual code. This fixes a fuzz bug that arose from oss-fuzz over the
weekend.
* Rename `MmapVec::drain` to `split_off`
As suggested on #4609
* Fix tests
* Make MmapVec::split_off work like Vec::split_off
Co-authored-by: Jamey Sharp <jsharp@fastly.com>
* Remove recursion building types in `component_api` fuzzer
Sure enough the fuzzers found an input that blows the stack, so the
type-building here was rewritten to use a heap-based stack instead of a
stack-based-stack.
* Review comments
