7d8931c517
Previously each module in a module-linking-using-module would compile all the trampolines for all signatures for all modules. In forest-like situations with lots of modules this would cause quite a few trampolines to get compiled. The original intention was to have one global list of trampolines for all modules in the module-linking graph that they could all share. With the current design of module linking, however, the intention is for modules to be relatively isolated from one another which would make achieving this difficult. In lieu of total sharing (which would be good for the global scope anyway but we also don't do that right now) this commit implements an alternative strategy where each module simply compiles its own trampolines that it itself can reach. This should mean that module-linking modules behave more similarly to standalone modules in terms of trampoline duplication. If we ever do global trampoline deduplication we can likely batch this all together into one, but for now this should fix the performance issues seen in fuzzing. Closes #2525
543 lines
19 KiB
Rust
543 lines
19 KiB
Rust
//! Define the `instantiate` function, which takes a byte array containing an
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//! encoded wasm module and returns a live wasm instance. Also, define
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//! `CompiledModule` to allow compiling and instantiating to be done as separate
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//! steps.
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use crate::code_memory::CodeMemory;
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use crate::compiler::{Compilation, Compiler};
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use crate::link::link_module;
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use crate::object::ObjectUnwindInfo;
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use object::File as ObjectFile;
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#[cfg(feature = "parallel-compilation")]
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use rayon::prelude::*;
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use serde::{Deserialize, Serialize};
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use std::ops::Range;
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use std::sync::Arc;
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use thiserror::Error;
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use wasmtime_debug::create_gdbjit_image;
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use wasmtime_environ::entity::PrimaryMap;
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use wasmtime_environ::isa::TargetIsa;
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use wasmtime_environ::wasm::{
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DefinedFuncIndex, InstanceTypeIndex, ModuleTypeIndex, SignatureIndex, WasmFuncType,
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};
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use wasmtime_environ::{
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CompileError, DebugInfoData, FunctionAddressMap, InstanceSignature, Module, ModuleEnvironment,
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ModuleSignature, ModuleTranslation, StackMapInformation, TrapInformation,
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};
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use wasmtime_profiling::ProfilingAgent;
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use wasmtime_runtime::{GdbJitImageRegistration, InstantiationError, VMFunctionBody, VMTrampoline};
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/// An error condition while setting up a wasm instance, be it validation,
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/// compilation, or instantiation.
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#[derive(Error, Debug)]
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pub enum SetupError {
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/// The module did not pass validation.
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#[error("Validation error: {0}")]
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Validate(String),
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/// A wasm translation error occured.
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#[error("WebAssembly failed to compile")]
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Compile(#[from] CompileError),
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/// Some runtime resource was unavailable or insufficient, or the start function
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/// trapped.
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#[error("Instantiation failed during setup")]
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Instantiate(#[from] InstantiationError),
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/// Debug information generation error occured.
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#[error("Debug information error")]
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DebugInfo(#[from] anyhow::Error),
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}
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/// Contains all compilation artifacts.
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#[derive(Serialize, Deserialize)]
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pub struct CompilationArtifacts {
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/// Module metadata.
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#[serde(with = "arc_serde")]
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module: Arc<Module>,
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/// ELF image with functions code.
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obj: Box<[u8]>,
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/// Unwind information for function code.
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unwind_info: Box<[ObjectUnwindInfo]>,
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/// Descriptions of compiled functions
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funcs: PrimaryMap<DefinedFuncIndex, FunctionInfo>,
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/// Whether or not native debug information is available in `obj`
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native_debug_info_present: bool,
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/// Whether or not the original wasm module contained debug information that
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/// we skipped and did not parse.
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has_unparsed_debuginfo: bool,
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/// Debug information found in the wasm file, used for symbolicating
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/// backtraces.
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debug_info: Option<DebugInfo>,
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}
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#[derive(Serialize, Deserialize)]
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struct DebugInfo {
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data: Box<[u8]>,
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code_section_offset: u64,
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debug_abbrev: Range<usize>,
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debug_addr: Range<usize>,
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debug_info: Range<usize>,
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debug_line: Range<usize>,
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debug_line_str: Range<usize>,
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debug_ranges: Range<usize>,
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debug_rnglists: Range<usize>,
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debug_str: Range<usize>,
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debug_str_offsets: Range<usize>,
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}
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impl CompilationArtifacts {
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/// Creates a `CompilationArtifacts` for a singular translated wasm module.
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///
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/// The `use_paged_init` argument controls whether or not an attempt is made to
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/// organize linear memory initialization data as entire pages or to leave
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/// the memory initialization data as individual segments.
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pub fn build(
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compiler: &Compiler,
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data: &[u8],
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use_paged_mem_init: bool,
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) -> Result<(usize, Vec<CompilationArtifacts>, TypeTables), SetupError> {
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let (main_module, translations, types) = ModuleEnvironment::new(
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compiler.frontend_config(),
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compiler.tunables(),
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compiler.features(),
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)
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.translate(data)
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.map_err(|error| SetupError::Compile(CompileError::Wasm(error)))?;
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let list = maybe_parallel!(translations.(into_iter | into_par_iter))
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.map(|mut translation| {
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let Compilation {
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obj,
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unwind_info,
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funcs,
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} = compiler.compile(&mut translation, &types)?;
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let ModuleTranslation {
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mut module,
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debuginfo,
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has_unparsed_debuginfo,
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..
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} = translation;
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if use_paged_mem_init {
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if let Some(init) = module.memory_initialization.to_paged(&module) {
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module.memory_initialization = init;
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}
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}
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let obj = obj.write().map_err(|_| {
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SetupError::Instantiate(InstantiationError::Resource(anyhow::anyhow!(
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"failed to create image memory"
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)))
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})?;
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Ok(CompilationArtifacts {
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module: Arc::new(module),
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obj: obj.into_boxed_slice(),
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unwind_info: unwind_info.into_boxed_slice(),
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funcs: funcs
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.into_iter()
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.map(|(_, func)| FunctionInfo {
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stack_maps: func.stack_maps,
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traps: func.traps,
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address_map: func.address_map,
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})
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.collect(),
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native_debug_info_present: compiler.tunables().generate_native_debuginfo,
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debug_info: if compiler.tunables().parse_wasm_debuginfo {
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Some(debuginfo.into())
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} else {
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None
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},
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has_unparsed_debuginfo,
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})
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})
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.collect::<Result<Vec<_>, SetupError>>()?;
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Ok((
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main_module,
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list,
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TypeTables {
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wasm_signatures: types.wasm_signatures,
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module_signatures: types.module_signatures,
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instance_signatures: types.instance_signatures,
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},
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))
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}
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}
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struct FinishedFunctions(PrimaryMap<DefinedFuncIndex, *mut [VMFunctionBody]>);
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unsafe impl Send for FinishedFunctions {}
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unsafe impl Sync for FinishedFunctions {}
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#[derive(Serialize, Deserialize, Clone)]
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struct FunctionInfo {
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traps: Vec<TrapInformation>,
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address_map: FunctionAddressMap,
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stack_maps: Vec<StackMapInformation>,
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}
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/// This is intended to mirror the type tables in `wasmtime_environ`, except that
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/// it doesn't store the native signatures which are no longer needed past compilation.
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#[derive(Serialize, Deserialize)]
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#[allow(missing_docs)]
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pub struct TypeTables {
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pub wasm_signatures: PrimaryMap<SignatureIndex, WasmFuncType>,
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pub module_signatures: PrimaryMap<ModuleTypeIndex, ModuleSignature>,
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pub instance_signatures: PrimaryMap<InstanceTypeIndex, InstanceSignature>,
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}
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/// Container for data needed for an Instance function to exist.
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pub struct ModuleCode {
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code_memory: CodeMemory,
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#[allow(dead_code)]
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dbg_jit_registration: Option<GdbJitImageRegistration>,
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}
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/// A compiled wasm module, ready to be instantiated.
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pub struct CompiledModule {
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artifacts: CompilationArtifacts,
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code: Arc<ModuleCode>,
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finished_functions: FinishedFunctions,
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trampolines: Vec<(SignatureIndex, VMTrampoline)>,
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}
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impl CompiledModule {
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/// Creates a list of compiled modules from the given list of compilation
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/// artifacts.
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pub fn from_artifacts_list(
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artifacts: Vec<CompilationArtifacts>,
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isa: &dyn TargetIsa,
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profiler: &dyn ProfilingAgent,
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) -> Result<Vec<Arc<Self>>, SetupError> {
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maybe_parallel!(artifacts.(into_iter | into_par_iter))
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.map(|a| CompiledModule::from_artifacts(a, isa, profiler))
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.collect()
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}
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/// Creates `CompiledModule` directly from `CompilationArtifacts`.
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pub fn from_artifacts(
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artifacts: CompilationArtifacts,
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isa: &dyn TargetIsa,
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profiler: &dyn ProfilingAgent,
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) -> Result<Arc<Self>, SetupError> {
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// Allocate all of the compiled functions into executable memory,
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// copying over their contents.
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let (code_memory, code_range, finished_functions, trampolines) = build_code_memory(
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isa,
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&artifacts.obj,
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&artifacts.module,
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&artifacts.unwind_info,
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)
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.map_err(|message| {
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SetupError::Instantiate(InstantiationError::Resource(anyhow::anyhow!(
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"failed to build code memory for functions: {}",
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message
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)))
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})?;
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// Register GDB JIT images; initialize profiler and load the wasm module.
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let dbg_jit_registration = if artifacts.native_debug_info_present {
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let bytes = create_dbg_image(
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artifacts.obj.to_vec(),
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code_range,
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&artifacts.module,
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&finished_functions,
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)?;
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profiler.module_load(&artifacts.module, &finished_functions, Some(&bytes));
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let reg = GdbJitImageRegistration::register(bytes);
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Some(reg)
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} else {
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profiler.module_load(&artifacts.module, &finished_functions, None);
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None
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};
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let finished_functions = FinishedFunctions(finished_functions);
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Ok(Arc::new(Self {
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artifacts,
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code: Arc::new(ModuleCode {
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code_memory,
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dbg_jit_registration,
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}),
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finished_functions,
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trampolines,
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}))
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}
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/// Extracts `CompilationArtifacts` from the compiled module.
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pub fn compilation_artifacts(&self) -> &CompilationArtifacts {
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&self.artifacts
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}
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/// Return a reference-counting pointer to a module.
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pub fn module(&self) -> &Arc<Module> {
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&self.artifacts.module
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}
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/// Return a reference to a mutable module (if possible).
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pub fn module_mut(&mut self) -> Option<&mut Module> {
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Arc::get_mut(&mut self.artifacts.module)
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}
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/// Returns the map of all finished JIT functions compiled for this module
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pub fn finished_functions(&self) -> &PrimaryMap<DefinedFuncIndex, *mut [VMFunctionBody]> {
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&self.finished_functions.0
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}
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/// Returns the per-signature trampolines for this module.
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pub fn trampolines(&self) -> &[(SignatureIndex, VMTrampoline)] {
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&self.trampolines
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}
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/// Returns the stack map information for all functions defined in this
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/// module.
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///
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/// The iterator returned iterates over the span of the compiled function in
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/// memory with the stack maps associated with those bytes.
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pub fn stack_maps(
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&self,
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) -> impl Iterator<Item = (*mut [VMFunctionBody], &[StackMapInformation])> {
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self.finished_functions().values().copied().zip(
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self.artifacts
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.funcs
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.values()
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.map(|f| f.stack_maps.as_slice()),
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)
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}
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/// Iterates over all functions in this module, returning information about
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/// how to decode traps which happen in the function.
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pub fn trap_information(
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&self,
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) -> impl Iterator<
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Item = (
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DefinedFuncIndex,
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*mut [VMFunctionBody],
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&[TrapInformation],
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&FunctionAddressMap,
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),
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> {
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self.finished_functions()
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.iter()
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.zip(self.artifacts.funcs.values())
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.map(|((i, alloc), func)| (i, *alloc, func.traps.as_slice(), &func.address_map))
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}
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/// Returns all ranges convered by JIT code.
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pub fn jit_code_ranges<'a>(&'a self) -> impl Iterator<Item = (usize, usize)> + 'a {
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self.code.code_memory.published_ranges()
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}
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/// Returns module's JIT code.
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pub fn code(&self) -> &Arc<ModuleCode> {
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&self.code
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}
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/// Creates a new symbolication context which can be used to further
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/// symbolicate stack traces.
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///
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/// Basically this makes a thing which parses debuginfo and can tell you
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/// what filename and line number a wasm pc comes from.
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pub fn symbolize_context(&self) -> Result<Option<SymbolizeContext>, gimli::Error> {
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use gimli::EndianSlice;
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let info = match &self.artifacts.debug_info {
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Some(info) => info,
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None => return Ok(None),
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};
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// For now we clone the data into the `SymbolizeContext`, but if this
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// becomes prohibitive we could always `Arc` it with our own allocation
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// here.
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let data = info.data.clone();
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let endian = gimli::LittleEndian;
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let cx = addr2line::Context::from_sections(
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EndianSlice::new(&data[info.debug_abbrev.clone()], endian).into(),
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EndianSlice::new(&data[info.debug_addr.clone()], endian).into(),
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EndianSlice::new(&data[info.debug_info.clone()], endian).into(),
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EndianSlice::new(&data[info.debug_line.clone()], endian).into(),
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EndianSlice::new(&data[info.debug_line_str.clone()], endian).into(),
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EndianSlice::new(&data[info.debug_ranges.clone()], endian).into(),
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EndianSlice::new(&data[info.debug_rnglists.clone()], endian).into(),
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EndianSlice::new(&data[info.debug_str.clone()], endian).into(),
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EndianSlice::new(&data[info.debug_str_offsets.clone()], endian).into(),
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EndianSlice::new(&[], endian),
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)?;
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Ok(Some(SymbolizeContext {
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// See comments on `SymbolizeContext` for why we do this static
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// lifetime promotion.
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inner: unsafe {
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std::mem::transmute::<Addr2LineContext<'_>, Addr2LineContext<'static>>(cx)
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},
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code_section_offset: info.code_section_offset,
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_data: data,
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}))
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}
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/// Returns whether the original wasm module had unparsed debug information
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/// based on the tunables configuration.
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pub fn has_unparsed_debuginfo(&self) -> bool {
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self.artifacts.has_unparsed_debuginfo
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}
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}
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type Addr2LineContext<'a> = addr2line::Context<gimli::EndianSlice<'a, gimli::LittleEndian>>;
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/// A context which contains dwarf debug information to translate program
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/// counters back to filenames and line numbers.
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pub struct SymbolizeContext {
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// Note the `'static` lifetime on `inner`. That's actually a bunch of slices
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// which point back into the `_data` field. We currently unsafely manage
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// this by saying that when inside the struct it's `'static` (since we own
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// the referenced data just next to it) and we only loan out borrowed
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// references.
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_data: Box<[u8]>,
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inner: Addr2LineContext<'static>,
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code_section_offset: u64,
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}
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impl SymbolizeContext {
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/// Returns access to the [`addr2line::Context`] which can be used to query
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/// frame information with.
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pub fn addr2line(&self) -> &Addr2LineContext<'_> {
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// Here we demote our synthetic `'static` lifetime which doesn't
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// actually exist back to a lifetime that's tied to `&self`, which
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// should be safe.
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unsafe {
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std::mem::transmute::<&Addr2LineContext<'static>, &Addr2LineContext<'_>>(&self.inner)
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}
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}
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/// Returns the offset of the code section in the original wasm file, used
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/// to calculate lookup values into the DWARF.
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pub fn code_section_offset(&self) -> u64 {
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self.code_section_offset
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}
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}
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fn create_dbg_image(
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obj: Vec<u8>,
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code_range: (*const u8, usize),
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module: &Module,
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finished_functions: &PrimaryMap<DefinedFuncIndex, *mut [VMFunctionBody]>,
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) -> Result<Vec<u8>, SetupError> {
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let funcs = finished_functions
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.values()
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.map(|allocated: &*mut [VMFunctionBody]| (*allocated) as *const u8)
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.collect::<Vec<_>>();
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create_gdbjit_image(obj, code_range, module.num_imported_funcs, &funcs)
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.map_err(SetupError::DebugInfo)
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}
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fn build_code_memory(
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isa: &dyn TargetIsa,
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obj: &[u8],
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module: &Module,
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unwind_info: &Box<[ObjectUnwindInfo]>,
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) -> Result<
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(
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CodeMemory,
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(*const u8, usize),
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PrimaryMap<DefinedFuncIndex, *mut [VMFunctionBody]>,
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Vec<(SignatureIndex, VMTrampoline)>,
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),
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String,
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> {
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let obj = ObjectFile::parse(obj).map_err(|_| "Unable to read obj".to_string())?;
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let mut code_memory = CodeMemory::new();
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let allocation = code_memory.allocate_for_object(&obj, unwind_info)?;
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// Second, create a PrimaryMap from result vector of pointers.
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let mut finished_functions = PrimaryMap::new();
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for (i, fat_ptr) in allocation.funcs() {
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let fat_ptr: *mut [VMFunctionBody] = fat_ptr;
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assert_eq!(
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Some(finished_functions.push(fat_ptr)),
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module.defined_func_index(i)
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);
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}
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let trampolines = allocation
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|
.trampolines()
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.map(|(i, fat_ptr)| {
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let fnptr = unsafe {
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std::mem::transmute::<*const VMFunctionBody, VMTrampoline>(fat_ptr.as_ptr())
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};
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(i, fnptr)
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})
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.collect();
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let code_range = allocation.code_range();
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link_module(&obj, &module, code_range, &finished_functions);
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let code_range = (code_range.as_ptr(), code_range.len());
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// Make all code compiled thus far executable.
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code_memory.publish(isa);
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Ok((code_memory, code_range, finished_functions, trampolines))
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}
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|
|
impl From<DebugInfoData<'_>> for DebugInfo {
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|
fn from(raw: DebugInfoData<'_>) -> DebugInfo {
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use gimli::Section;
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|
|
|
let mut data = Vec::new();
|
|
let mut push = |section: &[u8]| {
|
|
data.extend_from_slice(section);
|
|
data.len() - section.len()..data.len()
|
|
};
|
|
let debug_abbrev = push(raw.dwarf.debug_abbrev.reader().slice());
|
|
let debug_addr = push(raw.dwarf.debug_addr.reader().slice());
|
|
let debug_info = push(raw.dwarf.debug_info.reader().slice());
|
|
let debug_line = push(raw.dwarf.debug_line.reader().slice());
|
|
let debug_line_str = push(raw.dwarf.debug_line_str.reader().slice());
|
|
let debug_ranges = push(raw.debug_ranges.reader().slice());
|
|
let debug_rnglists = push(raw.debug_rnglists.reader().slice());
|
|
let debug_str = push(raw.dwarf.debug_str.reader().slice());
|
|
let debug_str_offsets = push(raw.dwarf.debug_str_offsets.reader().slice());
|
|
DebugInfo {
|
|
data: data.into(),
|
|
debug_abbrev,
|
|
debug_addr,
|
|
debug_info,
|
|
debug_line,
|
|
debug_line_str,
|
|
debug_ranges,
|
|
debug_rnglists,
|
|
debug_str,
|
|
debug_str_offsets,
|
|
code_section_offset: raw.wasm_file.code_section_offset,
|
|
}
|
|
}
|
|
}
|
|
|
|
mod arc_serde {
|
|
use super::Arc;
|
|
use serde::{de::Deserialize, ser::Serialize, Deserializer, Serializer};
|
|
|
|
pub(super) fn serialize<S, T>(arc: &Arc<T>, ser: S) -> Result<S::Ok, S::Error>
|
|
where
|
|
S: Serializer,
|
|
T: Serialize,
|
|
{
|
|
(**arc).serialize(ser)
|
|
}
|
|
|
|
pub(super) fn deserialize<'de, D, T>(de: D) -> Result<Arc<T>, D::Error>
|
|
where
|
|
D: Deserializer<'de>,
|
|
T: Deserialize<'de>,
|
|
{
|
|
Ok(Arc::new(T::deserialize(de)?))
|
|
}
|
|
}
|