wasmer_compiler/
compiler.rs

1//! This module mainly outputs the `Compiler` trait that custom
2//! compilers will need to implement.
3
4use std::cmp::Reverse;
5
6use crate::progress::ProgressContext;
7use crate::types::module::CompileModuleInfo;
8use crate::{
9    FunctionBodyData, ModuleTranslationState,
10    lib::std::{boxed::Box, sync::Arc},
11    translator::ModuleMiddleware,
12    types::function::Compilation,
13};
14use crossbeam_channel::unbounded;
15use enumset::EnumSet;
16use itertools::Itertools;
17use wasmer_types::{
18    CompilationProgressCallback, Features, LocalFunctionIndex,
19    entity::PrimaryMap,
20    error::CompileError,
21    target::{CpuFeature, Target, UserCompilerOptimizations},
22};
23#[cfg(feature = "translator")]
24use wasmparser::{Validator, WasmFeatures};
25
26/// The compiler configuration options.
27pub trait CompilerConfig {
28    /// Enable Position Independent Code (PIC).
29    ///
30    /// This is required for shared object generation (Native Engine),
31    /// but will make the JIT Engine to fail, since PIC is not yet
32    /// supported in the JIT linking phase.
33    fn enable_pic(&mut self) {
34        // By default we do nothing, each backend will need to customize this
35        // in case they do something special for emitting PIC code.
36    }
37
38    /// Enable compiler IR verification.
39    ///
40    /// For compilers capable of doing so, this enables internal consistency
41    /// checking.
42    fn enable_verifier(&mut self) {
43        // By default we do nothing, each backend will need to customize this
44        // in case they create an IR that they can verify.
45    }
46
47    /// Enable generation of perfmaps to sample the JIT compiled frames.
48    fn enable_perfmap(&mut self) {
49        // By default we do nothing, each backend will need to customize this
50        // in case they create an IR that they can verify.
51    }
52
53    /// For the LLVM compiler, we can use non-volatile memory operations which lead to a better performance
54    /// (but are not 100% SPEC compliant).
55    fn enable_non_volatile_memops(&mut self) {}
56
57    /// Enable run-time handling of potentially unaligned memory accesses.
58    ///
59    /// This feature is experimental and currently supports only Cranelift scalar types
60    /// and Singlepass on RISC-V for integral types.
61    fn enable_experimental_unaligned_memory_accesses(&mut self) {}
62
63    /// Enables treating eligible funcref tables as read-only so the backend can
64    /// place them in read-only data.
65    fn enable_readonly_funcref_table(&mut self) {}
66
67    /// Enable NaN canonicalization.
68    ///
69    /// NaN canonicalization is useful when trying to run WebAssembly
70    /// deterministically across different architectures.
71    fn canonicalize_nans(&mut self, _enable: bool) {
72        // By default we do nothing, each backend will need to customize this
73        // in case they create an IR that they can verify.
74    }
75
76    /// Gets the custom compiler config
77    fn compiler(self: Box<Self>) -> Box<dyn Compiler>;
78
79    /// Gets the default features for this compiler in the given target
80    fn default_features_for_target(&self, target: &Target) -> Features {
81        self.supported_features_for_target(target)
82    }
83
84    /// Gets the supported features for this compiler in the given target
85    fn supported_features_for_target(&self, _target: &Target) -> Features {
86        Features::default()
87    }
88
89    /// Pushes a middleware onto the back of the middleware chain.
90    fn push_middleware(&mut self, middleware: Arc<dyn ModuleMiddleware>);
91}
92
93impl<T> From<T> for Box<dyn CompilerConfig + 'static>
94where
95    T: CompilerConfig + 'static,
96{
97    fn from(other: T) -> Self {
98        Box::new(other)
99    }
100}
101
102/// An implementation of a Compiler from parsed WebAssembly module to Compiled native code.
103pub trait Compiler: Send + std::fmt::Debug {
104    /// Returns a descriptive name for this compiler.
105    ///
106    /// Note that this is an API breaking change since 3.0
107    fn name(&self) -> &str;
108
109    /// Returns the deterministic id of this compiler. Same compilers with different
110    /// optimizations map to different deterministic IDs.
111    fn deterministic_id(&self) -> String;
112
113    /// Add suggested optimizations to this compiler.
114    ///
115    /// # Note
116    ///
117    /// Not every compiler supports every optimization. This function may fail (i.e. not set the
118    /// suggested optimizations) silently if the underlying compiler does not support one or
119    /// more optimizations.
120    fn with_opts(
121        &mut self,
122        suggested_compiler_opts: &UserCompilerOptimizations,
123    ) -> Result<(), CompileError> {
124        _ = suggested_compiler_opts;
125        Ok(())
126    }
127
128    /// Validates a module.
129    ///
130    /// It returns the a successful Result in case is valid, `CompileError` in case is not.
131    #[cfg(feature = "translator")]
132    fn validate_module(&self, features: &Features, data: &[u8]) -> Result<(), CompileError> {
133        let mut wasm_features = WasmFeatures::empty();
134        wasm_features.set(WasmFeatures::BULK_MEMORY, features.bulk_memory);
135        wasm_features.set(WasmFeatures::THREADS, features.threads);
136        wasm_features.set(WasmFeatures::REFERENCE_TYPES, features.reference_types);
137        wasm_features.set(WasmFeatures::MULTI_VALUE, features.multi_value);
138        wasm_features.set(WasmFeatures::SIMD, features.simd);
139        wasm_features.set(WasmFeatures::TAIL_CALL, features.tail_call);
140        wasm_features.set(WasmFeatures::MULTI_MEMORY, features.multi_memory);
141        wasm_features.set(WasmFeatures::MEMORY64, features.memory64);
142        wasm_features.set(WasmFeatures::EXCEPTIONS, features.exceptions);
143        wasm_features.set(WasmFeatures::EXTENDED_CONST, features.extended_const);
144        wasm_features.set(WasmFeatures::RELAXED_SIMD, features.relaxed_simd);
145        wasm_features.set(WasmFeatures::WIDE_ARITHMETIC, features.wide_arithmetic);
146        wasm_features.set(WasmFeatures::TAIL_CALL, features.tail_call);
147        wasm_features.set(WasmFeatures::MUTABLE_GLOBAL, true);
148        wasm_features.set(WasmFeatures::SATURATING_FLOAT_TO_INT, true);
149        wasm_features.set(WasmFeatures::FLOATS, true);
150        wasm_features.set(WasmFeatures::SIGN_EXTENSION, true);
151        wasm_features.set(WasmFeatures::GC_TYPES, true);
152
153        let mut validator = Validator::new_with_features(wasm_features);
154        validator
155            .validate_all(data)
156            .map_err(|e| CompileError::Validate(format!("{e}")))?;
157        Ok(())
158    }
159
160    /// Compiles a parsed module.
161    ///
162    /// It returns the [`Compilation`] or a [`CompileError`].
163    fn compile_module(
164        &self,
165        target: &Target,
166        module: &CompileModuleInfo,
167        module_translation: &ModuleTranslationState,
168        // The list of function bodies
169        function_body_inputs: PrimaryMap<LocalFunctionIndex, FunctionBodyData<'_>>,
170        progress_callback: Option<&CompilationProgressCallback>,
171    ) -> Result<Compilation, CompileError>;
172
173    /// Get the middlewares for this compiler
174    fn get_middlewares(&self) -> &[Arc<dyn ModuleMiddleware>];
175
176    /// Get whether translation-time readonly funcref table analysis should run.
177    fn enable_readonly_funcref_table(&self) -> bool {
178        false
179    }
180
181    /// Get the CpuFeatures used by the compiler
182    fn get_cpu_features_used(&self, cpu_features: &EnumSet<CpuFeature>) -> EnumSet<CpuFeature> {
183        *cpu_features
184    }
185
186    /// Get whether `perfmap` is enabled or not.
187    fn get_perfmap_enabled(&self) -> bool {
188        false
189    }
190}
191
192/// A bucket containing a group of functions and their total size, used to balance compilation units for parallel compilation.
193pub struct FunctionBucket<'a> {
194    functions: Vec<(LocalFunctionIndex, &'a FunctionBodyData<'a>)>,
195    /// IR size of the bucket (in bytes).
196    pub size: usize,
197}
198
199impl<'a> FunctionBucket<'a> {
200    /// Creates a new, empty `FunctionBucket`.
201    pub fn new() -> Self {
202        Self {
203            functions: Vec::new(),
204            size: 0,
205        }
206    }
207}
208
209/// Build buckets sized by function length to keep compilation units balanced for parallel compilation.
210pub fn build_function_buckets<'a>(
211    function_body_inputs: &'a PrimaryMap<LocalFunctionIndex, FunctionBodyData<'a>>,
212    bucket_threshold_size: u64,
213) -> Vec<FunctionBucket<'a>> {
214    let mut function_bodies = function_body_inputs
215        .iter()
216        .sorted_by_key(|(id, body)| Reverse((body.data.len(), id.as_u32())))
217        .collect_vec();
218
219    let mut buckets = Vec::new();
220
221    while !function_bodies.is_empty() {
222        let mut next_function_body = Vec::with_capacity(function_bodies.len());
223        let mut bucket = FunctionBucket::new();
224
225        for (fn_index, fn_body) in function_bodies.into_iter() {
226            if bucket.size + fn_body.data.len() <= bucket_threshold_size as usize
227                // Huge functions must fit into a bucket!
228                || bucket.size == 0
229            {
230                bucket.size += fn_body.data.len();
231                bucket.functions.push((fn_index, fn_body));
232            } else {
233                next_function_body.push((fn_index, fn_body));
234            }
235        }
236
237        function_bodies = next_function_body;
238        buckets.push(bucket);
239    }
240
241    buckets
242}
243
244/// Represents a function that has been compiled by the backend compiler.
245pub trait CompiledFunction {}
246
247/// Translates a function from its input representation to a compiled form.
248pub trait FuncTranslator {}
249
250/// Compile function buckets largest-first via the channel (instead of Rayon's par_iter).
251#[allow(clippy::too_many_arguments)]
252pub fn translate_function_buckets<'a, C, T, F, G>(
253    pool: &rayon::ThreadPool,
254    func_translator_builder: F,
255    translate_fn: G,
256    progress: Option<ProgressContext>,
257    buckets: &[FunctionBucket<'a>],
258) -> Result<Vec<C>, CompileError>
259where
260    T: FuncTranslator,
261    C: CompiledFunction + Send + Sync,
262    F: Fn() -> T + Send + Sync + Copy,
263    G: Fn(&mut T, &LocalFunctionIndex, &FunctionBodyData) -> Result<C, CompileError>
264        + Send
265        + Sync
266        + Copy,
267{
268    let progress = progress.as_ref();
269
270    let functions = pool.install(|| {
271        let (bucket_tx, bucket_rx) = unbounded::<&FunctionBucket<'a>>();
272        for bucket in buckets {
273            bucket_tx.send(bucket).map_err(|e| {
274                CompileError::Resource(format!("cannot allocate crossbeam channel item: {e}"))
275            })?;
276        }
277        drop(bucket_tx);
278
279        let (result_tx, result_rx) =
280            unbounded::<Result<Vec<(LocalFunctionIndex, C)>, CompileError>>();
281
282        pool.scope(|s| {
283            let worker_count = pool.current_num_threads().max(1);
284            for _ in 0..worker_count {
285                let bucket_rx = bucket_rx.clone();
286                let result_tx = result_tx.clone();
287                s.spawn(move |_| {
288                    let mut func_translator = func_translator_builder();
289
290                    while let Ok(bucket) = bucket_rx.recv() {
291                        let bucket_result = (|| {
292                            let mut translated_functions = Vec::new();
293                            for (i, input) in bucket.functions.iter() {
294                                let translated = translate_fn(&mut func_translator, i, input)?;
295                                if let Some(progress) = progress {
296                                    progress.notify_steps(input.data.len() as u64)?;
297                                }
298                                translated_functions.push((*i, translated));
299                            }
300                            Ok(translated_functions)
301                        })();
302
303                        if result_tx.send(bucket_result).is_err() {
304                            break;
305                        }
306                    }
307                });
308            }
309        });
310
311        drop(result_tx);
312        let mut functions = Vec::with_capacity(buckets.iter().map(|b| b.functions.len()).sum());
313        for _ in 0..buckets.len() {
314            match result_rx.recv().map_err(|e| {
315                CompileError::Resource(format!("cannot allocate crossbeam channel item: {e}"))
316            })? {
317                Ok(bucket_functions) => functions.extend(bucket_functions),
318                Err(err) => return Err(err),
319            }
320        }
321        Ok(functions)
322    })?;
323
324    Ok(functions
325        .into_iter()
326        .sorted_by_key(|x| x.0)
327        .map(|(_, body)| body)
328        .collect_vec())
329}
330
331/// Byte size threshold for a function that is considered large.
332pub const WASM_LARGE_FUNCTION_THRESHOLD: u64 = 100_000;
333
334/// Estimated byte size of a trampoline (used for progress bar reporting).
335pub const WASM_TRAMPOLINE_ESTIMATED_BODY_SIZE: u64 = 1_000;
wasmer_compiler/compiler.rs

wasmer_compiler/
compiler.rs
