9ac7d01288
This commit is intended to do almost everything necessary for processing the alias section of module linking. Most of this is internal refactoring, the highlights being: * Type contents are now stored separately from a `wasmtime_env::Module`. Given that modules can freely alias types and have them used all over the place, it seemed best to have one canonical location to type storage which everywhere else points to (with indices). A new `TypeTables` structure is produced during compilation which is shared amongst all member modules in a wasm blob. * Instantiation is heavily refactored to account for module linking. The main gotcha here is that imports are now listed as "initializers". We have a sort of pseudo-bytecode-interpreter which interprets the initialization of a module. This is more complicated than just matching imports at this point because in the module linking proposal the module, alias, import, and instance sections may all be interleaved. This means that imports aren't guaranteed to show up at the beginning of the address space for modules/instances. Otherwise most of the changes here largely fell out from these two design points. Aliases are recorded as initializers in this scheme. Copying around type information and/or just knowing type information during compilation is also pretty easy since everything is just a pointer into a `TypeTables` and we don't have to actually copy any types themselves. Lots of various refactorings were necessary to accomodate these changes. Tests are hoped to cover a breadth of functionality here, but not necessarily a depth. There's still one more piece of the module linking proposal missing which is exporting instances/modules, which will come in a future PR. It's also worth nothing that there's one large TODO which isn't implemented in this change that I plan on opening an issue for. With module linking when a set of modules comes back from compilation each modules has all the trampolines for the entire set of modules. This is quite a lot of duplicate trampolines across module-linking modules. We'll want to refactor this at some point to instead have only one set of trampolines per set of module linking modules and have them shared from there. I figured it was best to separate out this change, however, since it's purely related to resource usage, and doesn't impact non-module-linking modules at all. cc #2094
110 lines
3.7 KiB
Rust
110 lines
3.7 KiB
Rust
//! A `Compilation` contains the compiled function bodies for a WebAssembly
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//! module.
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use crate::{FunctionAddressMap, FunctionBodyData, ModuleTranslation, Tunables, TypeTables};
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use cranelift_codegen::{binemit, ir, isa, isa::unwind::UnwindInfo};
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use cranelift_entity::PrimaryMap;
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use cranelift_wasm::{DefinedFuncIndex, FuncIndex, WasmError};
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use serde::{Deserialize, Serialize};
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use thiserror::Error;
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#[allow(missing_docs)]
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pub type CompiledFunctions = PrimaryMap<DefinedFuncIndex, CompiledFunction>;
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/// Compiled function: machine code body, jump table offsets, and unwind information.
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#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq, Default)]
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#[allow(missing_docs)]
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pub struct CompiledFunction {
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/// The machine code for this function.
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pub body: Vec<u8>,
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/// The jump tables offsets (in the body).
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pub jt_offsets: ir::JumpTableOffsets,
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/// The unwind information.
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pub unwind_info: Option<UnwindInfo>,
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pub relocations: Vec<Relocation>,
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pub address_map: FunctionAddressMap,
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pub value_labels_ranges: cranelift_codegen::ValueLabelsRanges,
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pub stack_slots: ir::StackSlots,
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pub traps: Vec<TrapInformation>,
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pub stack_maps: Vec<StackMapInformation>,
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}
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/// A record of a relocation to perform.
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#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq)]
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pub struct Relocation {
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/// The relocation code.
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pub reloc: binemit::Reloc,
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/// Relocation target.
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pub reloc_target: RelocationTarget,
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/// The offset where to apply the relocation.
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pub offset: binemit::CodeOffset,
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/// The addend to add to the relocation value.
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pub addend: binemit::Addend,
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}
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/// Destination function. Can be either user function or some special one, like `memory.grow`.
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#[derive(Serialize, Deserialize, Debug, Copy, Clone, PartialEq, Eq)]
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pub enum RelocationTarget {
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/// The user function index.
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UserFunc(FuncIndex),
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/// A compiler-generated libcall.
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LibCall(ir::LibCall),
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/// Jump table index.
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JumpTable(FuncIndex, ir::JumpTable),
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}
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/// Information about trap.
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#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
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pub struct TrapInformation {
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/// The offset of the trapping instruction in native code. It is relative to the beginning of the function.
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pub code_offset: binemit::CodeOffset,
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/// Code of the trap.
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pub trap_code: ir::TrapCode,
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}
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/// The offset within a function of a GC safepoint, and its associated stack
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/// map.
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#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
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pub struct StackMapInformation {
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/// The offset of the GC safepoint within the function's native code. It is
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/// relative to the beginning of the function.
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pub code_offset: binemit::CodeOffset,
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/// The stack map for identifying live GC refs at the GC safepoint.
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pub stack_map: binemit::StackMap,
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}
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/// An error while compiling WebAssembly to machine code.
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#[derive(Error, Debug)]
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pub enum CompileError {
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/// A wasm translation error occured.
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#[error("WebAssembly translation error")]
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Wasm(#[from] WasmError),
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/// A compilation error occured.
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#[error("Compilation error: {0}")]
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Codegen(String),
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/// A compilation error occured.
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#[error("Debug info is not supported with this configuration")]
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DebugInfoNotSupported,
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}
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/// An implementation of a compiler from parsed WebAssembly module to native
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/// code.
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pub trait Compiler: Send + Sync {
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/// Compile a function with the given `TargetIsa`.
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fn compile_function(
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&self,
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translation: &ModuleTranslation<'_>,
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index: DefinedFuncIndex,
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data: FunctionBodyData<'_>,
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isa: &dyn isa::TargetIsa,
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tunables: &Tunables,
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types: &TypeTables,
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) -> Result<CompiledFunction, CompileError>;
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}
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