1 use crate::prelude::*; 2 #[cfg(feature = "std")] 3 use crate::runtime::vm::open_file_for_mmap; 4 use crate::runtime::vm::{CompiledModuleId, MmapVec, ModuleMemoryImages, VMWasmCallFunction}; 5 use crate::sync::OnceLock; 6 use crate::{ 7 Engine, 8 code::CodeObject, 9 code_memory::CodeMemory, 10 instantiate::CompiledModule, 11 resources::ResourcesRequired, 12 types::{ExportType, ExternType, ImportType}, 13 }; 14 use alloc::sync::Arc; 15 use core::fmt; 16 use core::ops::Range; 17 use core::ptr::NonNull; 18 #[cfg(feature = "std")] 19 use std::{fs::File, path::Path}; 20 use wasmparser::{Parser, ValidPayload, Validator}; 21 #[cfg(feature = "debug")] 22 use wasmtime_environ::FrameTable; 23 use wasmtime_environ::{ 24 CompiledFunctionsTable, CompiledModuleInfo, EntityIndex, HostPtr, ModuleTypes, ObjectKind, 25 TypeTrace, VMOffsets, VMSharedTypeIndex, 26 }; 27 #[cfg(feature = "gc")] 28 use wasmtime_unwinder::ExceptionTable; 29 mod registry; 30 31 pub use registry::*; 32 33 /// A compiled WebAssembly module, ready to be instantiated. 34 /// 35 /// A `Module` is a compiled in-memory representation of an input WebAssembly 36 /// binary. A `Module` is then used to create an [`Instance`](crate::Instance) 37 /// through an instantiation process. You cannot call functions or fetch 38 /// globals, for example, on a `Module` because it's purely a code 39 /// representation. Instead you'll need to create an 40 /// [`Instance`](crate::Instance) to interact with the wasm module. 41 /// 42 /// A `Module` can be created by compiling WebAssembly code through APIs such as 43 /// [`Module::new`]. This would be a JIT-style use case where code is compiled 44 /// just before it's used. Alternatively a `Module` can be compiled in one 45 /// process and [`Module::serialize`] can be used to save it to storage. A later 46 /// call to [`Module::deserialize`] will quickly load the module to execute and 47 /// does not need to compile any code, representing a more AOT-style use case. 48 /// 49 /// Currently a `Module` does not implement any form of tiering or dynamic 50 /// optimization of compiled code. Creation of a `Module` via [`Module::new`] or 51 /// related APIs will perform the entire compilation step synchronously. When 52 /// finished no further compilation will happen at runtime or later during 53 /// execution of WebAssembly instances for example. 54 /// 55 /// Compilation of WebAssembly by default goes through Cranelift and is 56 /// recommended to be done once-per-module. The same WebAssembly binary need not 57 /// be compiled multiple times and can instead used an embedder-cached result of 58 /// the first call. 59 /// 60 /// `Module` is thread-safe and safe to share across threads. 61 /// 62 /// ## Modules and `Clone` 63 /// 64 /// Using `clone` on a `Module` is a cheap operation. It will not create an 65 /// entirely new module, but rather just a new reference to the existing module. 66 /// In other words it's a shallow copy, not a deep copy. 67 /// 68 /// ## Examples 69 /// 70 /// There are a number of ways you can create a `Module`, for example pulling 71 /// the bytes from a number of locations. One example is loading a module from 72 /// the filesystem: 73 /// 74 /// ```no_run 75 /// # use wasmtime::*; 76 /// # fn main() -> anyhow::Result<()> { 77 /// let engine = Engine::default(); 78 /// let module = Module::from_file(&engine, "path/to/foo.wasm")?; 79 /// # Ok(()) 80 /// # } 81 /// ``` 82 /// 83 /// You can also load the wasm text format if more convenient too: 84 /// 85 /// ```no_run 86 /// # use wasmtime::*; 87 /// # fn main() -> anyhow::Result<()> { 88 /// let engine = Engine::default(); 89 /// // Now we're using the WebAssembly text extension: `.wat`! 90 /// let module = Module::from_file(&engine, "path/to/foo.wat")?; 91 /// # Ok(()) 92 /// # } 93 /// ``` 94 /// 95 /// And if you've already got the bytes in-memory you can use the 96 /// [`Module::new`] constructor: 97 /// 98 /// ```no_run 99 /// # use wasmtime::*; 100 /// # fn main() -> anyhow::Result<()> { 101 /// let engine = Engine::default(); 102 /// # let wasm_bytes: Vec<u8> = Vec::new(); 103 /// let module = Module::new(&engine, &wasm_bytes)?; 104 /// 105 /// // It also works with the text format! 106 /// let module = Module::new(&engine, "(module (func))")?; 107 /// # Ok(()) 108 /// # } 109 /// ``` 110 /// 111 /// Serializing and deserializing a module looks like: 112 /// 113 /// ```no_run 114 /// # use wasmtime::*; 115 /// # fn main() -> anyhow::Result<()> { 116 /// let engine = Engine::default(); 117 /// # let wasm_bytes: Vec<u8> = Vec::new(); 118 /// let module = Module::new(&engine, &wasm_bytes)?; 119 /// let module_bytes = module.serialize()?; 120 /// 121 /// // ... can save `module_bytes` to disk or other storage ... 122 /// 123 /// // recreate the module from the serialized bytes. For the `unsafe` bits 124 /// // see the documentation of `deserialize`. 125 /// let module = unsafe { Module::deserialize(&engine, &module_bytes)? }; 126 /// # Ok(()) 127 /// # } 128 /// ``` 129 /// 130 /// [`Config`]: crate::Config 131 #[derive(Clone)] 132 pub struct Module { 133 inner: Arc<ModuleInner>, 134 } 135 136 struct ModuleInner { 137 engine: Engine, 138 /// The compiled artifacts for this module that will be instantiated and 139 /// executed. 140 module: CompiledModule, 141 142 /// Runtime information such as the underlying mmap, type information, etc. 143 /// 144 /// Note that this `Arc` is used to share information between compiled 145 /// modules within a component. For bare core wasm modules created with 146 /// `Module::new`, for example, this is a uniquely owned `Arc`. 147 code: Arc<CodeObject>, 148 149 /// A set of initialization images for memories, if any. 150 /// 151 /// Note that this is behind a `OnceCell` to lazily create this image. On 152 /// Linux where `memfd_create` may be used to create the backing memory 153 /// image this is a pretty expensive operation, so by deferring it this 154 /// improves memory usage for modules that are created but may not ever be 155 /// instantiated. 156 memory_images: OnceLock<Option<ModuleMemoryImages>>, 157 158 /// Flag indicating whether this module can be serialized or not. 159 #[cfg(any(feature = "cranelift", feature = "winch"))] 160 serializable: bool, 161 162 /// Runtime offset information for `VMContext`. 163 offsets: VMOffsets<HostPtr>, 164 } 165 166 impl fmt::Debug for Module { 167 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { 168 f.debug_struct("Module") 169 .field("name", &self.name()) 170 .finish_non_exhaustive() 171 } 172 } 173 174 impl fmt::Debug for ModuleInner { 175 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { 176 f.debug_struct("ModuleInner") 177 .field("name", &self.module.module().name.as_ref()) 178 .finish_non_exhaustive() 179 } 180 } 181 182 impl Module { 183 /// Creates a new WebAssembly `Module` from the given in-memory `bytes`. 184 /// 185 /// The `bytes` provided must be in one of the following formats: 186 /// 187 /// * A [binary-encoded][binary] WebAssembly module. This is always supported. 188 /// * A [text-encoded][text] instance of the WebAssembly text format. 189 /// This is only supported when the `wat` feature of this crate is enabled. 190 /// If this is supplied then the text format will be parsed before validation. 191 /// Note that the `wat` feature is enabled by default. 192 /// 193 /// The data for the wasm module must be loaded in-memory if it's present 194 /// elsewhere, for example on disk. This requires that the entire binary is 195 /// loaded into memory all at once, this API does not support streaming 196 /// compilation of a module. 197 /// 198 /// The WebAssembly binary will be decoded and validated. It will also be 199 /// compiled according to the configuration of the provided `engine`. 200 /// 201 /// # Errors 202 /// 203 /// This function may fail and return an error. Errors may include 204 /// situations such as: 205 /// 206 /// * The binary provided could not be decoded because it's not a valid 207 /// WebAssembly binary 208 /// * The WebAssembly binary may not validate (e.g. contains type errors) 209 /// * Implementation-specific limits were exceeded with a valid binary (for 210 /// example too many locals) 211 /// * The wasm binary may use features that are not enabled in the 212 /// configuration of `engine` 213 /// * If the `wat` feature is enabled and the input is text, then it may be 214 /// rejected if it fails to parse. 215 /// 216 /// The error returned should contain full information about why module 217 /// creation failed if one is returned. 218 /// 219 /// [binary]: https://webassembly.github.io/spec/core/binary/index.html 220 /// [text]: https://webassembly.github.io/spec/core/text/index.html 221 /// 222 /// # Examples 223 /// 224 /// The `new` function can be invoked with a in-memory array of bytes: 225 /// 226 /// ```no_run 227 /// # use wasmtime::*; 228 /// # fn main() -> anyhow::Result<()> { 229 /// # let engine = Engine::default(); 230 /// # let wasm_bytes: Vec<u8> = Vec::new(); 231 /// let module = Module::new(&engine, &wasm_bytes)?; 232 /// # Ok(()) 233 /// # } 234 /// ``` 235 /// 236 /// Or you can also pass in a string to be parsed as the wasm text 237 /// format: 238 /// 239 /// ``` 240 /// # use wasmtime::*; 241 /// # fn main() -> anyhow::Result<()> { 242 /// # let engine = Engine::default(); 243 /// let module = Module::new(&engine, "(module (func))")?; 244 /// # Ok(()) 245 /// # } 246 /// ``` 247 #[cfg(any(feature = "cranelift", feature = "winch"))] 248 pub fn new(engine: &Engine, bytes: impl AsRef<[u8]>) -> Result<Module> { 249 crate::CodeBuilder::new(engine) 250 .wasm_binary_or_text(bytes.as_ref(), None)? 251 .compile_module() 252 } 253 254 /// Creates a new WebAssembly `Module` from the contents of the given 255 /// `file` on disk. 256 /// 257 /// This is a convenience function that will read the `file` provided and 258 /// pass the bytes to the [`Module::new`] function. For more information 259 /// see [`Module::new`] 260 /// 261 /// # Examples 262 /// 263 /// ```no_run 264 /// # use wasmtime::*; 265 /// # fn main() -> anyhow::Result<()> { 266 /// let engine = Engine::default(); 267 /// let module = Module::from_file(&engine, "./path/to/foo.wasm")?; 268 /// # Ok(()) 269 /// # } 270 /// ``` 271 /// 272 /// The `.wat` text format is also supported: 273 /// 274 /// ```no_run 275 /// # use wasmtime::*; 276 /// # fn main() -> anyhow::Result<()> { 277 /// # let engine = Engine::default(); 278 /// let module = Module::from_file(&engine, "./path/to/foo.wat")?; 279 /// # Ok(()) 280 /// # } 281 /// ``` 282 #[cfg(all(feature = "std", any(feature = "cranelift", feature = "winch")))] 283 pub fn from_file(engine: &Engine, file: impl AsRef<Path>) -> Result<Module> { 284 crate::CodeBuilder::new(engine) 285 .wasm_binary_or_text_file(file.as_ref())? 286 .compile_module() 287 } 288 289 /// Creates a new WebAssembly `Module` from the given in-memory `binary` 290 /// data. 291 /// 292 /// This is similar to [`Module::new`] except that it requires that the 293 /// `binary` input is a WebAssembly binary, the text format is not supported 294 /// by this function. It's generally recommended to use [`Module::new`], but 295 /// if it's required to not support the text format this function can be 296 /// used instead. 297 /// 298 /// # Examples 299 /// 300 /// ``` 301 /// # use wasmtime::*; 302 /// # fn main() -> anyhow::Result<()> { 303 /// # let engine = Engine::default(); 304 /// let wasm = b"\0asm\x01\0\0\0"; 305 /// let module = Module::from_binary(&engine, wasm)?; 306 /// # Ok(()) 307 /// # } 308 /// ``` 309 /// 310 /// Note that the text format is **not** accepted by this function: 311 /// 312 /// ``` 313 /// # use wasmtime::*; 314 /// # fn main() -> anyhow::Result<()> { 315 /// # let engine = Engine::default(); 316 /// assert!(Module::from_binary(&engine, b"(module)").is_err()); 317 /// # Ok(()) 318 /// # } 319 /// ``` 320 #[cfg(any(feature = "cranelift", feature = "winch"))] 321 pub fn from_binary(engine: &Engine, binary: &[u8]) -> Result<Module> { 322 crate::CodeBuilder::new(engine) 323 .wasm_binary(binary, None)? 324 .compile_module() 325 } 326 327 /// Creates a new WebAssembly `Module` from the contents of the given `file` 328 /// on disk, but with assumptions that the file is from a trusted source. 329 /// The file should be a binary- or text-format WebAssembly module, or a 330 /// precompiled artifact generated by the same version of Wasmtime. 331 /// 332 /// # Unsafety 333 /// 334 /// All of the reasons that [`deserialize`] is `unsafe` apply to this 335 /// function as well. Arbitrary data loaded from a file may trick Wasmtime 336 /// into arbitrary code execution since the contents of the file are not 337 /// validated to be a valid precompiled module. 338 /// 339 /// [`deserialize`]: Module::deserialize 340 /// 341 /// Additionally though this function is also `unsafe` because the file 342 /// referenced must remain unchanged and a valid precompiled module for the 343 /// entire lifetime of the [`Module`] returned. Any changes to the file on 344 /// disk may change future instantiations of the module to be incorrect. 345 /// This is because the file is mapped into memory and lazily loaded pages 346 /// reflect the current state of the file, not necessarily the original 347 /// state of the file. 348 #[cfg(all(feature = "std", any(feature = "cranelift", feature = "winch")))] 349 pub unsafe fn from_trusted_file(engine: &Engine, file: impl AsRef<Path>) -> Result<Module> { 350 let open_file = open_file_for_mmap(file.as_ref())?; 351 let mmap = crate::runtime::vm::MmapVec::from_file(open_file)?; 352 if &mmap[0..4] == b"\x7fELF" { 353 let code = engine.load_code(mmap, ObjectKind::Module)?; 354 return Module::from_parts(engine, code, None); 355 } 356 357 crate::CodeBuilder::new(engine) 358 .wasm_binary_or_text(&mmap[..], Some(file.as_ref()))? 359 .compile_module() 360 } 361 362 /// Deserializes an in-memory compiled module previously created with 363 /// [`Module::serialize`] or [`Engine::precompile_module`]. 364 /// 365 /// This function will deserialize the binary blobs emitted by 366 /// [`Module::serialize`] and [`Engine::precompile_module`] back into an 367 /// in-memory [`Module`] that's ready to be instantiated. 368 /// 369 /// Note that the [`Module::deserialize_file`] method is more optimized than 370 /// this function, so if the serialized module is already present in a file 371 /// it's recommended to use that method instead. 372 /// 373 /// # Unsafety 374 /// 375 /// This function is marked as `unsafe` because if fed invalid input or used 376 /// improperly this could lead to memory safety vulnerabilities. This method 377 /// should not, for example, be exposed to arbitrary user input. 378 /// 379 /// The structure of the binary blob read here is only lightly validated 380 /// internally in `wasmtime`. This is intended to be an efficient 381 /// "rehydration" for a [`Module`] which has very few runtime checks beyond 382 /// deserialization. Arbitrary input could, for example, replace valid 383 /// compiled code with any other valid compiled code, meaning that this can 384 /// trivially be used to execute arbitrary code otherwise. 385 /// 386 /// For these reasons this function is `unsafe`. This function is only 387 /// designed to receive the previous input from [`Module::serialize`] and 388 /// [`Engine::precompile_module`]. If the exact output of those functions 389 /// (unmodified) is passed to this function then calls to this function can 390 /// be considered safe. It is the caller's responsibility to provide the 391 /// guarantee that only previously-serialized bytes are being passed in 392 /// here. 393 /// 394 /// Note that this function is designed to be safe receiving output from 395 /// *any* compiled version of `wasmtime` itself. This means that it is safe 396 /// to feed output from older versions of Wasmtime into this function, in 397 /// addition to newer versions of wasmtime (from the future!). These inputs 398 /// will deterministically and safely produce an `Err`. This function only 399 /// successfully accepts inputs from the same version of `wasmtime`, but the 400 /// safety guarantee only applies to externally-defined blobs of bytes, not 401 /// those defined by any version of wasmtime. (this means that if you cache 402 /// blobs across versions of wasmtime you can be safely guaranteed that 403 /// future versions of wasmtime will reject old cache entries). 404 pub unsafe fn deserialize(engine: &Engine, bytes: impl AsRef<[u8]>) -> Result<Module> { 405 let code = engine.load_code_bytes(bytes.as_ref(), ObjectKind::Module)?; 406 Module::from_parts(engine, code, None) 407 } 408 409 /// In-place deserialization of an in-memory compiled module previously 410 /// created with [`Module::serialize`] or [`Engine::precompile_module`]. 411 /// 412 /// See [`Self::deserialize`] for additional information; this method 413 /// works identically except that it will not create a copy of the provided 414 /// memory but will use it directly. 415 /// 416 /// # Unsafety 417 /// 418 /// All of the safety notes from [`Self::deserialize`] apply here as well 419 /// with the additional constraint that the code memory provide by `memory` 420 /// lives for as long as the module and is nevery externally modified for 421 /// the lifetime of the deserialized module. 422 pub unsafe fn deserialize_raw(engine: &Engine, memory: NonNull<[u8]>) -> Result<Module> { 423 // SAFETY: the contract required by `load_code_raw` is the same as this 424 // function. 425 let code = unsafe { engine.load_code_raw(memory, ObjectKind::Module)? }; 426 Module::from_parts(engine, code, None) 427 } 428 429 /// Same as [`deserialize`], except that the contents of `path` are read to 430 /// deserialize into a [`Module`]. 431 /// 432 /// This method is provided because it can be faster than [`deserialize`] 433 /// since the data doesn't need to be copied around, but rather the module 434 /// can be used directly from an mmap'd view of the file provided. 435 /// 436 /// [`deserialize`]: Module::deserialize 437 /// 438 /// # Unsafety 439 /// 440 /// All of the reasons that [`deserialize`] is `unsafe` applies to this 441 /// function as well. Arbitrary data loaded from a file may trick Wasmtime 442 /// into arbitrary code execution since the contents of the file are not 443 /// validated to be a valid precompiled module. 444 /// 445 /// Additionally though this function is also `unsafe` because the file 446 /// referenced must remain unchanged and a valid precompiled module for the 447 /// entire lifetime of the [`Module`] returned. Any changes to the file on 448 /// disk may change future instantiations of the module to be incorrect. 449 /// This is because the file is mapped into memory and lazily loaded pages 450 /// reflect the current state of the file, not necessarily the original 451 /// state of the file. 452 #[cfg(feature = "std")] 453 pub unsafe fn deserialize_file(engine: &Engine, path: impl AsRef<Path>) -> Result<Module> { 454 let file = open_file_for_mmap(path.as_ref())?; 455 // SAFETY: the contract of `deserialize_open_file` is the samea s this 456 // function. 457 unsafe { 458 Self::deserialize_open_file(engine, file) 459 .with_context(|| format!("failed deserialization for: {}", path.as_ref().display())) 460 } 461 } 462 463 /// Same as [`deserialize_file`], except that it takes an open `File` 464 /// instead of a path. 465 /// 466 /// This method is provided because it can be used instead of 467 /// [`deserialize_file`] in situations where `wasmtime` is running with 468 /// limited file system permissions. In that case a process 469 /// with file system access can pass already opened files to `wasmtime`. 470 /// 471 /// [`deserialize_file`]: Module::deserialize_file 472 /// 473 /// Note that the corresponding will be mapped as private writeable 474 /// (copy-on-write) and executable. For `windows` this means the file needs 475 /// to be opened with at least `FILE_GENERIC_READ | FILE_GENERIC_EXECUTE` 476 /// [`access_mode`]. 477 /// 478 /// [`access_mode`]: https://doc.rust-lang.org/std/os/windows/fs/trait.OpenOptionsExt.html#tymethod.access_mode 479 /// 480 /// # Unsafety 481 /// 482 /// All of the reasons that [`deserialize_file`] is `unsafe` applies to this 483 /// function as well. 484 #[cfg(feature = "std")] 485 pub unsafe fn deserialize_open_file(engine: &Engine, file: File) -> Result<Module> { 486 let code = engine.load_code_file(file, ObjectKind::Module)?; 487 Module::from_parts(engine, code, None) 488 } 489 490 /// Entrypoint for creating a `Module` for all above functions, both 491 /// of the AOT and jit-compiled categories. 492 /// 493 /// In all cases the compilation artifact, `code_memory`, is provided here. 494 /// The `info_and_types` argument is `None` when a module is being 495 /// deserialized from a precompiled artifact or it's `Some` if it was just 496 /// compiled and the values are already available. 497 pub(crate) fn from_parts( 498 engine: &Engine, 499 code_memory: Arc<CodeMemory>, 500 info_and_types: Option<(CompiledModuleInfo, CompiledFunctionsTable, ModuleTypes)>, 501 ) -> Result<Self> { 502 // Acquire this module's metadata and type information, deserializing 503 // it from the provided artifact if it wasn't otherwise provided 504 // already. 505 let (mut info, index, mut types) = match info_and_types { 506 Some((info, index, types)) => (info, index, types), 507 None => postcard::from_bytes(code_memory.wasmtime_info())?, 508 }; 509 510 // Register function type signatures into the engine for the lifetime 511 // of the `Module` that will be returned. This notably also builds up 512 // maps for trampolines to be used for this module when inserted into 513 // stores. 514 // 515 // Note that the unsafety here should be ok since the `trampolines` 516 // field should only point to valid trampoline function pointers 517 // within the text section. 518 let signatures = 519 engine.register_and_canonicalize_types(&mut types, core::iter::once(&mut info.module)); 520 521 // Package up all our data into a `CodeObject` and delegate to the final 522 // step of module compilation. 523 let code = Arc::new(CodeObject::new(code_memory, signatures, types.into())); 524 let index = Arc::new(index); 525 Module::from_parts_raw(engine, code, info, index, true) 526 } 527 528 pub(crate) fn from_parts_raw( 529 engine: &Engine, 530 code: Arc<CodeObject>, 531 info: CompiledModuleInfo, 532 index: Arc<CompiledFunctionsTable>, 533 serializable: bool, 534 ) -> Result<Self> { 535 let module = CompiledModule::from_artifacts( 536 code.code_memory().clone(), 537 info, 538 index, 539 engine.profiler(), 540 )?; 541 542 // Validate the module can be used with the current instance allocator. 543 let offsets = VMOffsets::new(HostPtr, module.module()); 544 engine 545 .allocator() 546 .validate_module(module.module(), &offsets)?; 547 548 let _ = serializable; 549 550 Ok(Self { 551 inner: Arc::new(ModuleInner { 552 engine: engine.clone(), 553 code, 554 memory_images: OnceLock::new(), 555 module, 556 #[cfg(any(feature = "cranelift", feature = "winch"))] 557 serializable, 558 offsets, 559 }), 560 }) 561 } 562 563 /// Validates `binary` input data as a WebAssembly binary given the 564 /// configuration in `engine`. 565 /// 566 /// This function will perform a speedy validation of the `binary` input 567 /// WebAssembly module (which is in [binary form][binary], the text format 568 /// is not accepted by this function) and return either `Ok` or `Err` 569 /// depending on the results of validation. The `engine` argument indicates 570 /// configuration for WebAssembly features, for example, which are used to 571 /// indicate what should be valid and what shouldn't be. 572 /// 573 /// Validation automatically happens as part of [`Module::new`]. 574 /// 575 /// # Errors 576 /// 577 /// If validation fails for any reason (type check error, usage of a feature 578 /// that wasn't enabled, etc) then an error with a description of the 579 /// validation issue will be returned. 580 /// 581 /// [binary]: https://webassembly.github.io/spec/core/binary/index.html 582 pub fn validate(engine: &Engine, binary: &[u8]) -> Result<()> { 583 let mut validator = Validator::new_with_features(engine.features()); 584 585 let mut functions = Vec::new(); 586 for payload in Parser::new(0).parse_all(binary) { 587 let payload = payload?; 588 if let ValidPayload::Func(a, b) = validator.payload(&payload)? { 589 functions.push((a, b)); 590 } 591 if let wasmparser::Payload::Version { encoding, .. } = &payload { 592 if let wasmparser::Encoding::Component = encoding { 593 bail!("component passed to module validation"); 594 } 595 } 596 } 597 598 engine.run_maybe_parallel(functions, |(validator, body)| { 599 // FIXME: it would be best here to use a rayon-specific parallel 600 // iterator that maintains state-per-thread to share the function 601 // validator allocations (`Default::default` here) across multiple 602 // functions. 603 validator.into_validator(Default::default()).validate(&body) 604 })?; 605 Ok(()) 606 } 607 608 /// Serializes this module to a vector of bytes. 609 /// 610 /// This function is similar to the [`Engine::precompile_module`] method 611 /// where it produces an artifact of Wasmtime which is suitable to later 612 /// pass into [`Module::deserialize`]. If a module is never instantiated 613 /// then it's recommended to use [`Engine::precompile_module`] instead of 614 /// this method, but if a module is both instantiated and serialized then 615 /// this method can be useful to get the serialized version without 616 /// compiling twice. 617 #[cfg(any(feature = "cranelift", feature = "winch"))] 618 pub fn serialize(&self) -> Result<Vec<u8>> { 619 // The current representation of compiled modules within a compiled 620 // component means that it cannot be serialized. The mmap returned here 621 // is the mmap for the entire component and while it contains all 622 // necessary data to deserialize this particular module it's all 623 // embedded within component-specific information. 624 // 625 // It's not the hardest thing in the world to support this but it's 626 // expected that there's not much of a use case at this time. In theory 627 // all that needs to be done is to edit the `.wasmtime.info` section 628 // to contains this module's metadata instead of the metadata for the 629 // whole component. The metadata itself is fairly trivially 630 // recreateable here it's more that there's no easy one-off API for 631 // editing the sections of an ELF object to use here. 632 // 633 // Overall for now this simply always returns an error in this 634 // situation. If you're reading this and feel that the situation should 635 // be different please feel free to open an issue. 636 if !self.inner.serializable { 637 bail!("cannot serialize a module exported from a component"); 638 } 639 Ok(self.compiled_module().mmap().to_vec()) 640 } 641 642 pub(crate) fn compiled_module(&self) -> &CompiledModule { 643 &self.inner.module 644 } 645 646 pub(crate) fn code_object(&self) -> &Arc<CodeObject> { 647 &self.inner.code 648 } 649 650 pub(crate) fn env_module(&self) -> &Arc<wasmtime_environ::Module> { 651 self.compiled_module().module() 652 } 653 654 pub(crate) fn types(&self) -> &ModuleTypes { 655 self.inner.code.module_types() 656 } 657 658 #[cfg(any(feature = "component-model", feature = "gc-drc"))] 659 pub(crate) fn signatures(&self) -> &crate::type_registry::TypeCollection { 660 self.inner.code.signatures() 661 } 662 663 /// Returns identifier/name that this [`Module`] has. This name 664 /// is used in traps/backtrace details. 665 /// 666 /// Note that most LLVM/clang/Rust-produced modules do not have a name 667 /// associated with them, but other wasm tooling can be used to inject or 668 /// add a name. 669 /// 670 /// # Examples 671 /// 672 /// ``` 673 /// # use wasmtime::*; 674 /// # fn main() -> anyhow::Result<()> { 675 /// # let engine = Engine::default(); 676 /// let module = Module::new(&engine, "(module $foo)")?; 677 /// assert_eq!(module.name(), Some("foo")); 678 /// 679 /// let module = Module::new(&engine, "(module)")?; 680 /// assert_eq!(module.name(), None); 681 /// 682 /// # Ok(()) 683 /// # } 684 /// ``` 685 pub fn name(&self) -> Option<&str> { 686 self.compiled_module().module().name.as_deref() 687 } 688 689 /// Returns the list of imports that this [`Module`] has and must be 690 /// satisfied. 691 /// 692 /// This function returns the list of imports that the wasm module has, but 693 /// only the types of each import. The type of each import is used to 694 /// typecheck the [`Instance::new`](crate::Instance::new) method's `imports` 695 /// argument. The arguments to that function must match up 1-to-1 with the 696 /// entries in the array returned here. 697 /// 698 /// The imports returned reflect the order of the imports in the wasm module 699 /// itself, and note that no form of deduplication happens. 700 /// 701 /// # Examples 702 /// 703 /// Modules with no imports return an empty list here: 704 /// 705 /// ``` 706 /// # use wasmtime::*; 707 /// # fn main() -> anyhow::Result<()> { 708 /// # let engine = Engine::default(); 709 /// let module = Module::new(&engine, "(module)")?; 710 /// assert_eq!(module.imports().len(), 0); 711 /// # Ok(()) 712 /// # } 713 /// ``` 714 /// 715 /// and modules with imports will have a non-empty list: 716 /// 717 /// ``` 718 /// # use wasmtime::*; 719 /// # fn main() -> anyhow::Result<()> { 720 /// # let engine = Engine::default(); 721 /// let wat = r#" 722 /// (module 723 /// (import "host" "foo" (func)) 724 /// ) 725 /// "#; 726 /// let module = Module::new(&engine, wat)?; 727 /// assert_eq!(module.imports().len(), 1); 728 /// let import = module.imports().next().unwrap(); 729 /// assert_eq!(import.module(), "host"); 730 /// assert_eq!(import.name(), "foo"); 731 /// match import.ty() { 732 /// ExternType::Func(_) => { /* ... */ } 733 /// _ => panic!("unexpected import type!"), 734 /// } 735 /// # Ok(()) 736 /// # } 737 /// ``` 738 pub fn imports<'module>( 739 &'module self, 740 ) -> impl ExactSizeIterator<Item = ImportType<'module>> + 'module { 741 let module = self.compiled_module().module(); 742 let types = self.types(); 743 let engine = self.engine(); 744 module 745 .imports() 746 .map(move |(imp_mod, imp_field, ty)| { 747 debug_assert!(ty.is_canonicalized_for_runtime_usage()); 748 ImportType::new(imp_mod, imp_field, ty, types, engine) 749 }) 750 .collect::<Vec<_>>() 751 .into_iter() 752 } 753 754 /// Returns the list of exports that this [`Module`] has and will be 755 /// available after instantiation. 756 /// 757 /// This function will return the type of each item that will be returned 758 /// from [`Instance::exports`](crate::Instance::exports). Each entry in this 759 /// list corresponds 1-to-1 with that list, and the entries here will 760 /// indicate the name of the export along with the type of the export. 761 /// 762 /// # Examples 763 /// 764 /// Modules might not have any exports: 765 /// 766 /// ``` 767 /// # use wasmtime::*; 768 /// # fn main() -> anyhow::Result<()> { 769 /// # let engine = Engine::default(); 770 /// let module = Module::new(&engine, "(module)")?; 771 /// assert!(module.exports().next().is_none()); 772 /// # Ok(()) 773 /// # } 774 /// ``` 775 /// 776 /// When the exports are not empty, you can inspect each export: 777 /// 778 /// ``` 779 /// # use wasmtime::*; 780 /// # fn main() -> anyhow::Result<()> { 781 /// # let engine = Engine::default(); 782 /// let wat = r#" 783 /// (module 784 /// (func (export "foo")) 785 /// (memory (export "memory") 1) 786 /// ) 787 /// "#; 788 /// let module = Module::new(&engine, wat)?; 789 /// assert_eq!(module.exports().len(), 2); 790 /// 791 /// let mut exports = module.exports(); 792 /// let foo = exports.next().unwrap(); 793 /// assert_eq!(foo.name(), "foo"); 794 /// match foo.ty() { 795 /// ExternType::Func(_) => { /* ... */ } 796 /// _ => panic!("unexpected export type!"), 797 /// } 798 /// 799 /// let memory = exports.next().unwrap(); 800 /// assert_eq!(memory.name(), "memory"); 801 /// match memory.ty() { 802 /// ExternType::Memory(_) => { /* ... */ } 803 /// _ => panic!("unexpected export type!"), 804 /// } 805 /// # Ok(()) 806 /// # } 807 /// ``` 808 pub fn exports<'module>( 809 &'module self, 810 ) -> impl ExactSizeIterator<Item = ExportType<'module>> + 'module { 811 let module = self.compiled_module().module(); 812 let types = self.types(); 813 let engine = self.engine(); 814 module.exports.iter().map(move |(name, entity_index)| { 815 ExportType::new(name, module.type_of(*entity_index), types, engine) 816 }) 817 } 818 819 /// Looks up an export in this [`Module`] by name. 820 /// 821 /// This function will return the type of an export with the given name. 822 /// 823 /// # Examples 824 /// 825 /// There may be no export with that name: 826 /// 827 /// ``` 828 /// # use wasmtime::*; 829 /// # fn main() -> anyhow::Result<()> { 830 /// # let engine = Engine::default(); 831 /// let module = Module::new(&engine, "(module)")?; 832 /// assert!(module.get_export("foo").is_none()); 833 /// # Ok(()) 834 /// # } 835 /// ``` 836 /// 837 /// When there is an export with that name, it is returned: 838 /// 839 /// ``` 840 /// # use wasmtime::*; 841 /// # fn main() -> anyhow::Result<()> { 842 /// # let engine = Engine::default(); 843 /// let wat = r#" 844 /// (module 845 /// (func (export "foo")) 846 /// (memory (export "memory") 1) 847 /// ) 848 /// "#; 849 /// let module = Module::new(&engine, wat)?; 850 /// let foo = module.get_export("foo"); 851 /// assert!(foo.is_some()); 852 /// 853 /// let foo = foo.unwrap(); 854 /// match foo { 855 /// ExternType::Func(_) => { /* ... */ } 856 /// _ => panic!("unexpected export type!"), 857 /// } 858 /// 859 /// # Ok(()) 860 /// # } 861 /// ``` 862 pub fn get_export(&self, name: &str) -> Option<ExternType> { 863 let module = self.compiled_module().module(); 864 let entity_index = module.exports.get(name)?; 865 Some(ExternType::from_wasmtime( 866 self.engine(), 867 self.types(), 868 &module.type_of(*entity_index), 869 )) 870 } 871 872 /// Looks up an export in this [`Module`] by name to get its index. 873 /// 874 /// This function will return the index of an export with the given name. This can be useful 875 /// to avoid the cost of looking up the export by name multiple times. Instead the 876 /// [`ModuleExport`] can be stored and used to look up the export on the 877 /// [`Instance`](crate::Instance) later. 878 pub fn get_export_index(&self, name: &str) -> Option<ModuleExport> { 879 let compiled_module = self.compiled_module(); 880 let module = compiled_module.module(); 881 let entity = *module.exports.get(name)?; 882 Some(ModuleExport { 883 module: self.id(), 884 entity, 885 }) 886 } 887 888 /// Returns the [`Engine`] that this [`Module`] was compiled by. 889 pub fn engine(&self) -> &Engine { 890 &self.inner.engine 891 } 892 893 /// Returns a summary of the resources required to instantiate this 894 /// [`Module`]. 895 /// 896 /// Potential uses of the returned information: 897 /// 898 /// * Determining whether your pooling allocator configuration supports 899 /// instantiating this module. 900 /// 901 /// * Deciding how many of which `Module` you want to instantiate within a 902 /// fixed amount of resources, e.g. determining whether to create 5 903 /// instances of module X or 10 instances of module Y. 904 /// 905 /// # Example 906 /// 907 /// ``` 908 /// # fn main() -> wasmtime::Result<()> { 909 /// use wasmtime::{Config, Engine, Module}; 910 /// 911 /// let mut config = Config::new(); 912 /// config.wasm_multi_memory(true); 913 /// let engine = Engine::new(&config)?; 914 /// 915 /// let module = Module::new(&engine, r#" 916 /// (module 917 /// ;; Import a memory. Doesn't count towards required resources. 918 /// (import "a" "b" (memory 10)) 919 /// ;; Define two local memories. These count towards the required 920 /// ;; resources. 921 /// (memory 1) 922 /// (memory 6) 923 /// ) 924 /// "#)?; 925 /// 926 /// let resources = module.resources_required(); 927 /// 928 /// // Instantiating the module will require allocating two memories, and 929 /// // the maximum initial memory size is six Wasm pages. 930 /// assert_eq!(resources.num_memories, 2); 931 /// assert_eq!(resources.max_initial_memory_size, Some(6)); 932 /// 933 /// // The module doesn't need any tables. 934 /// assert_eq!(resources.num_tables, 0); 935 /// assert_eq!(resources.max_initial_table_size, None); 936 /// # Ok(()) } 937 /// ``` 938 pub fn resources_required(&self) -> ResourcesRequired { 939 let em = self.env_module(); 940 let num_memories = u32::try_from(em.num_defined_memories()).unwrap(); 941 let max_initial_memory_size = em 942 .memories 943 .values() 944 .skip(em.num_imported_memories) 945 .map(|memory| memory.limits.min) 946 .max(); 947 let num_tables = u32::try_from(em.num_defined_tables()).unwrap(); 948 let max_initial_table_size = em 949 .tables 950 .values() 951 .skip(em.num_imported_tables) 952 .map(|table| table.limits.min) 953 .max(); 954 ResourcesRequired { 955 num_memories, 956 max_initial_memory_size, 957 num_tables, 958 max_initial_table_size, 959 } 960 } 961 962 /// Returns the range of bytes in memory where this module's compilation 963 /// image resides. 964 /// 965 /// The compilation image for a module contains executable code, data, debug 966 /// information, etc. This is roughly the same as the `Module::serialize` 967 /// but not the exact same. 968 /// 969 /// The range of memory reported here is exposed to allow low-level 970 /// manipulation of the memory in platform-specific manners such as using 971 /// `mlock` to force the contents to be paged in immediately or keep them 972 /// paged in after they're loaded. 973 /// 974 /// It is not safe to modify the memory in this range, nor is it safe to 975 /// modify the protections of memory in this range. 976 pub fn image_range(&self) -> Range<*const u8> { 977 self.compiled_module().mmap().image_range() 978 } 979 980 /// Force initialization of copy-on-write images to happen here-and-now 981 /// instead of when they're requested during first instantiation. 982 /// 983 /// When [copy-on-write memory 984 /// initialization](crate::Config::memory_init_cow) is enabled then Wasmtime 985 /// will lazily create the initialization image for a module. This method 986 /// can be used to explicitly dictate when this initialization happens. 987 /// 988 /// Note that this largely only matters on Linux when memfd is used. 989 /// Otherwise the copy-on-write image typically comes from disk and in that 990 /// situation the creation of the image is trivial as the image is always 991 /// sourced from disk. On Linux, though, when memfd is used a memfd is 992 /// created and the initialization image is written to it. 993 /// 994 /// Also note that this method is not required to be called, it's available 995 /// as a performance optimization if required but is otherwise handled 996 /// automatically. 997 pub fn initialize_copy_on_write_image(&self) -> Result<()> { 998 self.memory_images()?; 999 Ok(()) 1000 } 1001 1002 /// Get the map from `.text` section offsets to Wasm binary offsets for this 1003 /// module. 1004 /// 1005 /// Each entry is a (`.text` section offset, Wasm binary offset) pair. 1006 /// 1007 /// Entries are yielded in order of `.text` section offset. 1008 /// 1009 /// Some entries are missing a Wasm binary offset. This is for code that is 1010 /// not associated with any single location in the Wasm binary, or for when 1011 /// source information was optimized away. 1012 /// 1013 /// Not every module has an address map, since address map generation can be 1014 /// turned off on `Config`. 1015 /// 1016 /// There is not an entry for every `.text` section offset. Every offset 1017 /// after an entry's offset, but before the next entry's offset, is 1018 /// considered to map to the same Wasm binary offset as the original 1019 /// entry. For example, the address map will not contain the following 1020 /// sequence of entries: 1021 /// 1022 /// ```ignore 1023 /// [ 1024 /// // ... 1025 /// (10, Some(42)), 1026 /// (11, Some(42)), 1027 /// (12, Some(42)), 1028 /// (13, Some(43)), 1029 /// // ... 1030 /// ] 1031 /// ``` 1032 /// 1033 /// Instead, it will drop the entries for offsets `11` and `12` since they 1034 /// are the same as the entry for offset `10`: 1035 /// 1036 /// ```ignore 1037 /// [ 1038 /// // ... 1039 /// (10, Some(42)), 1040 /// (13, Some(43)), 1041 /// // ... 1042 /// ] 1043 /// ``` 1044 pub fn address_map<'a>(&'a self) -> Option<impl Iterator<Item = (usize, Option<u32>)> + 'a> { 1045 Some( 1046 wasmtime_environ::iterate_address_map( 1047 self.code_object().code_memory().address_map_data(), 1048 )? 1049 .map(|(offset, file_pos)| (offset as usize, file_pos.file_offset())), 1050 ) 1051 } 1052 1053 /// Get this module's code object's `.text` section, containing its compiled 1054 /// executable code. 1055 pub fn text(&self) -> &[u8] { 1056 self.code_object().code_memory().text() 1057 } 1058 1059 /// Get information about functions in this module's `.text` section: their 1060 /// index, name, and offset+length. 1061 /// 1062 /// Results are yielded in a ModuleFunction struct. 1063 pub fn functions<'a>(&'a self) -> impl ExactSizeIterator<Item = ModuleFunction> + 'a { 1064 let module = self.compiled_module(); 1065 module.finished_functions().map(|(idx, _)| { 1066 let loc = module.func_loc(idx); 1067 let idx = module.module().func_index(idx); 1068 ModuleFunction { 1069 index: idx, 1070 name: module.func_name(idx).map(|n| n.to_string()), 1071 offset: loc.start as usize, 1072 len: loc.length as usize, 1073 } 1074 }) 1075 } 1076 1077 pub(crate) fn id(&self) -> CompiledModuleId { 1078 self.inner.module.unique_id() 1079 } 1080 1081 pub(crate) fn offsets(&self) -> &VMOffsets<HostPtr> { 1082 &self.inner.offsets 1083 } 1084 1085 /// Return the address, in memory, of the trampoline that allows Wasm to 1086 /// call a array function of the given signature. 1087 pub(crate) fn wasm_to_array_trampoline( 1088 &self, 1089 signature: VMSharedTypeIndex, 1090 ) -> Option<NonNull<VMWasmCallFunction>> { 1091 log::trace!("Looking up trampoline for {signature:?}"); 1092 let trampoline_shared_ty = self.inner.engine.signatures().trampoline_type(signature); 1093 let trampoline_module_ty = self 1094 .inner 1095 .code 1096 .signatures() 1097 .trampoline_type(trampoline_shared_ty)?; 1098 debug_assert!( 1099 self.inner 1100 .engine 1101 .signatures() 1102 .borrow( 1103 self.inner 1104 .code 1105 .signatures() 1106 .shared_type(trampoline_module_ty) 1107 .unwrap() 1108 ) 1109 .unwrap() 1110 .unwrap_func() 1111 .is_trampoline_type() 1112 ); 1113 1114 let ptr = self 1115 .compiled_module() 1116 .wasm_to_array_trampoline(trampoline_module_ty) 1117 .expect("always have a trampoline for the trampoline type") 1118 .as_ptr() 1119 .cast::<VMWasmCallFunction>() 1120 .cast_mut(); 1121 Some(NonNull::new(ptr).unwrap()) 1122 } 1123 1124 pub(crate) fn memory_images(&self) -> Result<Option<&ModuleMemoryImages>> { 1125 let images = self 1126 .inner 1127 .memory_images 1128 .get_or_try_init(|| memory_images(&self.inner))? 1129 .as_ref(); 1130 Ok(images) 1131 } 1132 1133 /// Get the text offset (relative PC) for a given absolute PC in 1134 /// this module. 1135 #[cfg(any(feature = "gc", feature = "debug"))] 1136 pub(crate) fn text_offset(&self, pc: usize) -> u32 { 1137 u32::try_from(pc - self.inner.module.text().as_ptr() as usize).unwrap() 1138 } 1139 1140 /// Lookup the stack map at a program counter value. 1141 #[cfg(feature = "gc")] 1142 pub(crate) fn lookup_stack_map(&self, pc: usize) -> Option<wasmtime_environ::StackMap<'_>> { 1143 let text_offset = self.text_offset(pc); 1144 let info = self.inner.code.code_memory().stack_map_data(); 1145 wasmtime_environ::StackMap::lookup(text_offset, info) 1146 } 1147 1148 /// Obtain an exception-table parser on this module's exception metadata. 1149 #[cfg(feature = "gc")] 1150 pub(crate) fn exception_table<'a>(&'a self) -> ExceptionTable<'a> { 1151 ExceptionTable::parse(self.inner.code.code_memory().exception_tables()) 1152 .expect("Exception tables were validated on module load") 1153 } 1154 1155 /// Obtain a frame-table parser on this module's frame state slot 1156 /// (debug instrumentation) metadata. 1157 #[cfg(feature = "debug")] 1158 pub(crate) fn frame_table<'a>(&'a self) -> Option<FrameTable<'a>> { 1159 let data = self.inner.code.code_memory().frame_tables(); 1160 if data.is_empty() { 1161 None 1162 } else { 1163 Some(FrameTable::parse(data).expect("Frame tables were validated on module load")) 1164 } 1165 } 1166 } 1167 1168 /// Describes a function for a given module. 1169 pub struct ModuleFunction { 1170 pub index: wasmtime_environ::FuncIndex, 1171 pub name: Option<String>, 1172 pub offset: usize, 1173 pub len: usize, 1174 } 1175 1176 impl Drop for ModuleInner { 1177 fn drop(&mut self) { 1178 // When a `Module` is being dropped that means that it's no longer 1179 // present in any `Store` and it's additionally not longer held by any 1180 // embedder. Take this opportunity to purge any lingering instantiations 1181 // within a pooling instance allocator, if applicable. 1182 self.engine 1183 .allocator() 1184 .purge_module(self.module.unique_id()); 1185 } 1186 } 1187 1188 /// Describes the location of an export in a module. 1189 #[derive(Copy, Clone)] 1190 pub struct ModuleExport { 1191 /// The module that this export is defined in. 1192 pub(crate) module: CompiledModuleId, 1193 /// A raw index into the wasm module. 1194 pub(crate) entity: EntityIndex, 1195 } 1196 1197 fn _assert_send_sync() { 1198 fn _assert<T: Send + Sync>() {} 1199 _assert::<Module>(); 1200 } 1201 1202 /// Helper method to construct a `ModuleMemoryImages` for an associated 1203 /// `CompiledModule`. 1204 fn memory_images(inner: &Arc<ModuleInner>) -> Result<Option<ModuleMemoryImages>> { 1205 // If initialization via copy-on-write is explicitly disabled in 1206 // configuration then this path is skipped entirely. 1207 if !inner.engine.tunables().memory_init_cow { 1208 return Ok(None); 1209 } 1210 1211 // ... otherwise logic is delegated to the `ModuleMemoryImages::new` 1212 // constructor. 1213 ModuleMemoryImages::new( 1214 &inner.engine, 1215 inner.module.module(), 1216 inner.code.code_memory(), 1217 ) 1218 } 1219 1220 impl crate::vm::ModuleMemoryImageSource for CodeMemory { 1221 fn wasm_data(&self) -> &[u8] { 1222 <Self>::wasm_data(self) 1223 } 1224 1225 fn mmap(&self) -> Option<&MmapVec> { 1226 Some(<Self>::mmap(self)) 1227 } 1228 } 1229 1230 #[cfg(test)] 1231 mod tests { 1232 use crate::{Engine, Module}; 1233 use wasmtime_environ::MemoryInitialization; 1234 1235 #[test] 1236 fn cow_on_by_default() { 1237 let engine = Engine::default(); 1238 let module = Module::new( 1239 &engine, 1240 r#" 1241 (module 1242 (memory 1) 1243 (data (i32.const 100) "abcd") 1244 ) 1245 "#, 1246 ) 1247 .unwrap(); 1248 1249 let init = &module.env_module().memory_initialization; 1250 assert!(matches!(init, MemoryInitialization::Static { .. })); 1251 } 1252 } 1253