Struct ModuleBuilder 

pub struct ModuleBuilder { /* private fields */ }

Builds a Module.

Strings, structural types (everything but structs), and constants are deduplicated. Ids are dense and assigned in creation order. Functions are declared with function, which fixes their FuncId up front so they can call each other in any order, and are added with add_function.

Examples

use bytecode_lang::{Const, ExportItem, Inst, ModuleBuilder, ValType};

let mut m = ModuleBuilder::new();
let greeting = m.string("hello");
let k = m.constant(Const::Str(greeting));
let mut f = m.function("greet", &[], &[ValType::Str]);
let s = f.reg(ValType::Str);
f.emit(Inst::LoadConst { dst: s, k });
f.ret(s);
let greet = m.add_function(f).unwrap();
m.export("greet", ExportItem::Func(greet));
let module = m.finish().unwrap();
assert_eq!(module.string(greeting), Some("hello"));

Implementations

impl ModuleBuilder

pub fn new() -> Self

An empty module builder.

Examples

use bytecode_lang::ModuleBuilder;

let module = ModuleBuilder::new().finish().unwrap();
assert!(module.functions().is_empty());

pub fn string(&mut self, s: &str) -> StrId

The id of the string s, adding it on first use.

Examples

use bytecode_lang::{ModuleBuilder, StrId};

let mut m = ModuleBuilder::new();
assert_eq!(m.string("a"), StrId(0));
assert_eq!(m.string("b"), StrId(1));
assert_eq!(m.string("a"), StrId(0));

pub fn add_type(&mut self, def: TypeDef) -> TypeId

Adds a type and returns its id. Structural types (functions, arrays, maps, cells, iterators) are deduplicated; every struct is a new type.

Examples

use bytecode_lang::{ModuleBuilder, StructDef, TypeDef, ValType};

let mut m = ModuleBuilder::new();
let a = m.add_type(TypeDef::Array(ValType::I64));
assert_eq!(m.add_type(TypeDef::Array(ValType::I64)), a);
let s1 = m.add_type(TypeDef::Struct(StructDef::default()));
let s2 = m.add_type(TypeDef::Struct(StructDef::default()));
assert_ne!(s1, s2);

pub fn reserve_type(&mut self) -> TypeId

Reserves a type id to be defined later with define_type: how a struct refers to itself (a list node’s next field) or two structs refer to each other.

Examples

use bytecode_lang::{Field, ModuleBuilder, StructDef, TypeDef, ValType};

let mut m = ModuleBuilder::new();
let node = m.reserve_type();
let (name, next) = (m.string("Node"), m.string("next"));
m.define_type(node, TypeDef::Struct(StructDef {
    name,
    parent: None,
    fields: vec![Field { name: next, ty: ValType::Ref(node) }],
    methods: vec![],
}));
assert!(m.finish().is_ok());

pub fn define_type(&mut self, id: TypeId, def: TypeDef)

Defines a type reserved with reserve_type. Defining an id that was not reserved, or defining it twice, is recorded as UndefinedType.

Examples

use bytecode_lang::{ModuleBuilder, TypeDef, ValType};

let mut m = ModuleBuilder::new();
let t = m.reserve_type();
m.define_type(t, TypeDef::Cell(ValType::Dyn));
assert_eq!(m.finish().unwrap().type_def(t), Some(&TypeDef::Cell(ValType::Dyn)));

pub fn func_type(&mut self, params: &[ValType], results: &[ValType]) -> TypeId

The id of the function type (params) -> (results).

Examples

use bytecode_lang::{ModuleBuilder, ValType};

let mut m = ModuleBuilder::new();
let a = m.func_type(&[ValType::Dyn], &[ValType::Dyn]);
assert_eq!(m.func_type(&[ValType::Dyn], &[ValType::Dyn]), a);

pub fn constant(&mut self, c: Const) -> ConstId

Adds a constant and returns its id; equal constants share one id. An aggregate may only refer to constants that already exist (otherwise ConstForwardRef).

Examples

use bytecode_lang::{Const, ModuleBuilder};

let mut m = ModuleBuilder::new();
let one = m.constant(Const::Int(1));
let two = m.constant(Const::Int(2));
let list = m.constant(Const::Array(vec![one, two, one]));
assert_eq!(m.constant(Const::Int(1)), one);
assert_eq!(m.finish().unwrap().consts().len(), 3);

pub fn import(&mut self, module: &str, name: &str, sig: TypeId) -> ImportId

Adds a host-function import.

Examples

use bytecode_lang::{ImportId, ModuleBuilder, ValType};

let mut m = ModuleBuilder::new();
let sig = m.func_type(&[ValType::Str], &[]);
assert_eq!(m.import("ls.io", "print", sig), ImportId(0));

pub fn global( &mut self, name: &str, ty: ValType, mutable: bool, init: Option<ConstId>, ) -> GlobalId

Adds a global.

Examples

use bytecode_lang::{Const, GlobalId, ModuleBuilder, ValType};

let mut m = ModuleBuilder::new();
let zero = m.constant(Const::Int(0));
assert_eq!(m.global("hits", ValType::I64, true, Some(zero)), GlobalId(0));

pub fn function( &mut self, name: &str, params: &[ValType], results: &[ValType], ) -> FunctionBuilder

Declares a function and returns its builder. The function’s id is fixed now (FunctionBuilder::id), so other functions can call it before it is added.

Examples

use bytecode_lang::{FuncId, ModuleBuilder, ValType};

let mut m = ModuleBuilder::new();
let even = m.function("even", &[ValType::I64], &[ValType::Bool]);
let odd = m.function("odd", &[ValType::I64], &[ValType::Bool]);
assert_eq!((even.id(), odd.id()), (FuncId(0), FuncId(1)));

pub fn add_function(&mut self, f: FunctionBuilder) -> Result<FuncId, BuildError>

Resolves the function’s labels and places it in its slot.

Errors

The first error the function builder recorded, an unbound label, a branch target past the end, an inverted range, or ForeignFunction if the builder was not declared by this module builder or was already added.

Examples

use bytecode_lang::{BuildError, Inst, ModuleBuilder, Target};

let mut m = ModuleBuilder::new();
let mut f = m.function("f", &[], &[]);
f.emit(Inst::Jmp { target: Target(5) }); // raw target past the end
assert_eq!(
    m.add_function(f),
    Err(BuildError::TargetOutOfRange { func: bytecode_lang::FuncId(0), target: 5 }),
);

pub fn export(&mut self, name: &str, item: ExportItem)

Exports item under name.

Examples

use bytecode_lang::{ExportItem, ModuleBuilder, ValType};

let mut m = ModuleBuilder::new();
let g = m.global("version", ValType::I32, false, None);
m.export("version", ExportItem::Global(g));
assert_eq!(m.finish().unwrap().exports().len(), 1);

pub fn hook(&mut self, hook: Hook, callee: Callee)

Binds a dynamic-operation hook, replacing any earlier binding.

Examples

use bytecode_lang::{Callee, Hook, ModuleBuilder, ValType};

let mut m = ModuleBuilder::new();
let sig = m.func_type(&[ValType::Dyn, ValType::Dyn], &[ValType::Dyn]);
let loose_eq = m.import("mox.rt", "loose_eq", sig);
m.hook(Hook::Eq, Callee::Import(loose_eq));
let module = m.finish().unwrap();
assert_eq!(module.hook(Hook::Eq), Some(Callee::Import(loose_eq)));

pub fn set_name(&mut self, name: &str)

Names the module (the name the loader links imports against).

Examples

use bytecode_lang::ModuleBuilder;

let mut m = ModuleBuilder::new();
m.set_name("app");
assert!(m.finish().unwrap().name().is_some());

pub fn set_start(&mut self, func: FuncId)

Sets the initializer the loader runs after binding imports.

Examples

use bytecode_lang::{FuncId, ModuleBuilder};

let mut m = ModuleBuilder::new();
let mut f = m.function("init", &[], &[]);
f.ret_void();
let init = m.add_function(f).unwrap();
m.set_start(init);
assert_eq!(m.finish().unwrap().start(), Some(FuncId(0)));

pub fn finish(self) -> Result<Module, BuildError>

Produces the module.

Errors

The first error recorded while building, a declared function never added (UndefinedFunction), a reserved type never defined (UndefinedType), or a section too large to encode (TooLarge).

Examples

use bytecode_lang::{BuildError, FuncId, ModuleBuilder};

let mut m = ModuleBuilder::new();
let _forgotten = m.function("f", &[], &[]);
assert_eq!(m.finish().unwrap_err(), BuildError::UndefinedFunction(FuncId(0)));

Trait Implementations

impl Clone for ModuleBuilder

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ModuleBuilder

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for ModuleBuilder

fn default() -> Self

Returns the “default value” for a type.