Struct wasmtime_jit::ObjectBuilder

pub struct ObjectBuilder<'a> { /* private fields */ }

Helper structure to create an ELF file as a compilation artifact.

This structure exposes the process which Wasmtime will encode a core wasm module into an ELF file, notably managing data sections and all that good business going into the final file.

Implementations

impl<'a> ObjectBuilder<'a>

pub fn new(obj: Object<'a>, tunables: &'a Tunables) -> ObjectBuilder<'a>

Creates a new builder for the obj specified.

pub fn append( &mut self, translation: ModuleTranslation<'_>, funcs: PrimaryMap<DefinedFuncIndex, CompiledFunctionInfo>, wasm_to_native_trampolines: Vec<(SignatureIndex, FunctionLoc)> ) -> Result<CompiledModuleInfo>

Completes compilation of the translation specified, inserting everything necessary into the Object being built.

This function will consume the final results of compiling a wasm module and finish the ELF image in-progress as part of self.obj by appending any compiler-agnostic sections.

The auxiliary CompiledModuleInfo structure returned here has also been serialized into the object returned, but if the caller will quickly turn-around and invoke CompiledModule::from_artifacts after this then the information can be passed to that method to avoid extra deserialization. This is done to avoid a serialize-then-deserialize for API calls like Module::new where the compiled module is immediately going to be used.

The various arguments here are:

• translation - the core wasm translation that’s being completed.

• funcs - compilation metadata about functions within the translation as well as where the functions are located in the text section.

• array_to_wasm_trampolines - list of all trampolines necessary for array callers (e.g. Func::new) calling Wasm callees. One for each defined function that escapes. Must be sorted by DefinedFuncIndex.

• native_to_wasm_trampolines - list of all trampolines necessary for native callers (e.g. Func::wrap) calling Wasm callees. One for each defined function that escapes. Must be sorted by DefinedFuncIndex.

• wasm_to_native_trampolines - list of all trampolines necessary for Wasm callers calling native callees (e.g. Func::wrap). One for each function signature in the module. Must be sorted by SignatureIndex.

Returns the CompiledModuleInfo corresponding to this core Wasm module as a result of this append operation. This is then serialized into the final artifact by the caller.

pub fn serialize_info<T>(&mut self, info: &T)

where T: Serialize,

Creates the ELF_WASMTIME_INFO section from the given serializable data structure.

pub fn finish(self) -> Result<MmapVec>

Creates a new MmapVec from self.

The returned MmapVec will contain the serialized version of self and is sized appropriately to the exact size of the object serialized.