Struct wasmtime_cranelift_shared::obj::ModuleTextBuilder

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

A helper structure used to assemble the final text section of an exectuable, plus unwinding information and other related details.

This builder relies on Cranelift-specific internals but assembles into a generic Object which will get further appended to in a compiler-agnostic fashion later.

Implementations

impl<'a> ModuleTextBuilder<'a>

pub fn new( obj: &'a mut Object<'static>, compiler: &'a dyn Compiler, text: Box<dyn TextSectionBuilder>, ) -> Self

Creates a new builder for the text section of an executable.

The .text section will be appended to the specified obj along with any unwinding or such information as necessary. The num_funcs parameter indicates the number of times the append_func function will be called. The finish function will panic if this contract is not met.

pub fn append_func( &mut self, name: &str, body: &[u8], alignment: u32, unwind_info: Option<&'a UnwindInfo>, relocations: &[Relocation], resolve_reloc_target: impl Fn(FuncIndex) -> usize, ) -> (SymbolId, Range<u64>)

Appends the func specified named name to this object.

The resolve_reloc_target closure is used to resolve a relocation target to an adjacent function which has already been added or will be added to this object. The argument is the relocation target specified within CompiledFunction and the return value must be an index where the target will be defined by the nth call to append_func.

Returns the symbol associated with the function as well as the range that the function resides within the text section.

pub fn force_veneers(&mut self)

Forces “veneers” to be used for inter-function calls in the text section which means that in-bounds optimized addresses are never used.

This is only useful for debugging cranelift itself and typically this option is disabled.

pub fn append_padding(&mut self, padding: usize)

Appends the specified amount of bytes of padding into the text section.

This is only useful when fuzzing and/or debugging cranelift itself and for production scenarios padding is 0 and this function does nothing.

pub fn finish(self)

Indicates that the text section has been written completely and this will finish appending it to the original object.

Note that this will also write out the unwind information sections if necessary.