binaryen.js

binaryen.js is a port of Binaryen to the Web, allowing you to generate WebAssembly using a JavaScript API.

Usage

$> npm install binaryen

var binaryen = require("binaryen");

var myModule = new binaryen.Module();
myModule.addFunction("main", mod.addFunctionType("i", binaryen.i32, []), [], mod.return(mod.i32.const(0)));
myModule.addExport("main", "main");

var textData = myModule.emitText();
var wasmData = myModule.emitBinary();
...

The buildbot also publishes nightly versions once a day if there have been changes. The latest nightly can be installed through

$> npm install binaryen@nightly

or you can use one of the previous versions instead if necessary.

API

The API is documented in the rest of this document.

Types

• binaryen.none: The none type.
• binaryen.i32: The i32 type.
• binaryen.i64: The i64 type.
• binaryen.f32: The f32 type.
• binaryen.f64: The f64 type.

Modules

• binaryen.Module(): Constructor for a Binaryen WebAssembly module. You need to create one of these first.

Module instances have the following properties.

Module property operations:

• addFunctionType(name, resultType, paramTypes): Add a function type to the module, with a specified name, result type, and param types.
• getFunctionTypeBySignature(resultType, paramTypes): Gets an existing function type by its signature. Returns 0 if there is no such function type yet.
• addFunction(name, functionType, varTypes, body): Add a function, with a name, a function type, an array of local types, and a body.
• addImport(internalName, externalModuleName, externalBaseName, functionType): Add an import, with an internal name (used by other things in the module), an external module name (the module from which we import), an external base name (the name we import from that module), and a function type (for function imports).
• removeImport(internalName): Removes an import by its internal name.
• addExport(internalName, externalName): Add an export, with an internal name and an external name (the name the outside sees it exported as).
• removeExport(externalName): Removes an export by its external name.
• setFunctionTable(funcs): Sets the function table to a array of functions.
• setMemory(initial, maximum, exportName, segments): Sets the memory to having an initial size, maximum size, optional export name, and array of data segments.
• setStart(start): Sets the start function (called when the module is instantiated) to a specified function.

Module operations:

• emitBinary(): Returns a binary for the module, which you can then compile and run in the browser.
• emitAsmjs(): Returns the module converted to asm.js, which can be run in older browsers as well.
• emitText(): Returns a text representation of the module, in s-expression format.
• validate(): Validates the module, checking it for correctness. Returns 1 if the module is valid, otherwise 0.
• optimize(): Optimize the module.
• autoDrop(): Automatically inserts drop operations. This lets you not worry about dropping when creating your code.
• interpret(): Run the module in the Binaryen interpreter (creates the module, and calls the start method). Useful for debugging.
• dispose(): Cleans up the module. If the Binaryen object can be garbage-collected anyhow, you don't need to do this, but if it stays around - e.g. if you create multiple Modules over time - then you should call this once a Module is no longer needed. (As binaryen.js uses compiled C++ code, we can't just rely on normal garbage collection to clean things up internally.)

Type-prefixed expressions:

• i32:
  • i32.load(offset, align, ptr): Create a 32-bit load, with an offset, alignment, and pointer.
  • i32.load8_s(offset, align, ptr): Create an 8-bit signed load, with an offset, alignment, and pointer.
  • i32.load8_u(offset, align, ptr): Create an 8-bit unsigned load, with an offset, alignment, and pointer.
  • i32.load16_s(offset, align, ptr): Create an 16-bit signed load, with an offset, alignment, and pointer.
  • i32.load16_u(offset, align, ptr): Create an 16-bit unsigned load, with an offset, alignment, and pointer.
  • i32.store(offset, align, ptr, value): Create a 32-bit store, with an offset, alignment, pointer, and value.
  • i32.store8(offset, align, ptr, value): Create an 8-bit store, with an offset, alignment, pointer, and value.
  • i32.store16(offset, align, ptr, value): Create a 16-bit store, with an offset, alignment, pointer, and value.
  • i32.const(value): Create an i32 constant of a specified value.
  • i32.clz(value): Create a count-leading-zeros of a specified value.
  • i32.ctz(value): Create a count-trailing-zeros of a specified value.
  • i32.popcnt(value): Create a population-count (number of bits set) of a specified value.
  • i32.eqz(value): Create an equal-zero of a specified value.
  • i32.trunc_s.f32(value): Create a signed truncate of an f32 to an i32.
  • i32.trunc_s.f64(value): Create a signed truncate of an f64 to an i32.
  • i32.trunc_u.f32(value): Create an unsigned truncate of an f32 to an i32.
  • i32.trunc_u.f64(value): Create an unsigned truncate of an f64 to an i32.
  • i32.reinterpret(value): Create a reinterpret of an f32 to an i32.
  • i32.wrap(value): Create a wrap of an i64 to an i32.
  • i32.add(left, right): Create an add of two i32s.
  • i32.sub(left, right): Create a subtract of two i32s.
  • i32.mul(left, right): Create a multiply of two i32s.
  • i32.div_s(left, right): Create a signed divide of two i32s.
  • i32.div_u(left, right): Create an unsigned divide of two i32s.
  • i32.rem_s(left, right): Create a signed remainder of two i32s.
  • i32.rem_u(left, right): Create an unsigned remainder of two i32s.
  • i32.and(left, right): Create an and of two i32s.
  • i32.or(left, right): Create an or of two i32s.
  • i32.xor(left, right): Create a xor of two i32s.
  • i32.shl(left, right): Create a shift left on two i32s.
  • i32.shr_u(left, right): Create an unsigned (logical) shift right on two i32s.
  • i32.shr_s(left, right): Create a signed (arithmetic) shift right on two i32s.
  • i32.rotl(left, right): Create a rotate-left on two i32s.
  • i32.rotr(left, right): Create a rotate-right on two i32s.
  • i32.eq(left, right): Create an equals on two i32s.
  • i32.ne(left, right): Create a not-equals on two i32s.
  • i32.lt_s(left, right): Create a signed less-than on two i32s.
  • i32.lt_u(left, right): Create an unsigned less-than on two i32s.
  • i32.le_s(left, right): Create a signed less-or-equal on two i32s.
  • i32.le_u(left, right): Create an unsigned less-or-equal on two i32s.
  • i32.gt_s(left, right): Create a signed greater-than on two i32s.
  • i32.gt_u(left, right): Create an unsigned greater-than on two i32s.
  • i32.ge_s(left, right): Create a signed greater-or-equal on two i32s.
  • i32.ge_u(left, right): Create an unsigned greater-or-equal on two i32s.
• i64:
  • i64.load(offset, align, ptr): Create a 32-bit load, with an offset, alignment, and pointer.
  • i64.load8_s(offset, align, ptr): Create an 8-bit signed load, with an offset, alignment, and pointer.
  • i64.load8_u(offset, align, ptr): Create an 8-bit unsigned load, with an offset, alignment, and pointer.
  • i64.load16_s(offset, align, ptr): Create an 16-bit signed load, with an offset, alignment, and pointer.
  • i64.load16_u(offset, align, ptr): Create an 16-bit unsigned load, with an offset, alignment, and pointer.
  • i64.load32_s(offset, align, ptr): Create a 32-bit signed load, with an offset, alignment, and pointer.
  • i64.load32_u(offset, align, ptr): Create a 32-bit unsigned load, with an offset, alignment, and pointer.
  • i64.store(offset, align, ptr, value): Create a 32-bit store, with an offset, alignment, pointer, and value.
  • i64.store8(offset, align, ptr, value): Create an 8-bit store, with an offset, alignment, pointer, and value.
  • i64.store16(offset, align, ptr, value): Create a 16-bit store, with an offset, alignment, pointer, and value.
  • i64.store32(offset, align, ptr, value): Create a 32-bit store, with an offset, alignment, pointer, and value.
  • i64.const(low, high): Create an i64 constant of a specified value, provided as low and high 32 bits.
  • i64.clz(value): Create a count-leading-zeros of a specified value.
  • i64.ctz(value): Create a count-trailing-zeros of a specified value.
  • i64.popcnt(value): Create a population-count (number of bits set) of a specified value.
  • i64.eqz(value): Create an equal-zero of a specified value.
  • i64.trunc_s.f32(value): Create a signed truncate of an f32 to an i64.
  • i64.trunc_s.f64(value): Create a signed truncate of an f64 to an i64.
  • i64.trunc_u.f32(value): Create an unsigned truncate of an f32 to an i64.
  • i64.trunc_u.f64(value): Create an unsigned truncate of an f64 to an i64.
  • i64.reinterpret(value): Create a reinterpret of an f64 to an i64.
  • i64.extend_s(value): Create a signed extend of an i32 to an i64.
  • i64.extend_u(value): Create an unsigned extend of an i32 to an i64.
  • i64.add(left, right): Create an add of two i64s.
  • i64.sub(left, right): Create a subtract of two i64s.
  • i64.mul(left, right): Create a multiply of two i64s.
  • i64.div_s(left, right): Create a signed divide of two i64s.
  • i64.div_u(left, right): Create an unsigned divide of two i64s.
  • i64.rem_s(left, right): Create a signed remainder of two i64s.
  • i64.rem_u(left, right): Create an unsigned remainder of two i64s.
  • i64.and(left, right): Create an and of two i64s.
  • i64.or(left, right): Create an or of two i64s.
  • i64.xor(left, right): Create a xor of two i64s.
  • i64.shl(left, right): Create a shift left on two i64s.
  • i64.shr_u(left, right): Create an unsigned (logical) shift right on two i64s.
  • i64.shr_s(left, right): Create a signed (arithmetic) shift right on two i64s.
  • i64.rotl(left, right): Create a rotate-left on two i64s.
  • i64.rotr(left, right): Create a rotate-right on two i64s.
  • i64.eq(left, right): Create an equals on two i64s.
  • i64.ne(left, right): Create a not-equals on two i64s.
  • i64.lt_s(left, right): Create a signed less-than on two i64s.
  • i64.lt_u(left, right): Create an unsigned less-than on two i64s.
  • i64.le_s(left, right): Create a signed less-or-equal on two i64s.
  • i64.le_u(left, right): Create an unsigned less-or-equal on two i64s.
  • i64.gt_s(left, right): Create a signed greater-than on two i64s.
  • i64.gt_u(left, right): Create an unsigned greater-than on two i64s.
  • i64.ge_s(left, right): Create a signed greater-or-equal on two i64s.
  • i64.ge_u(left, right): Create an unsigned greater-or-equal on two i64s.
• f32:
  • f32.load(offset, align, ptr): Create an f32 load, with an offset, alignment, and pointer.
  • f32.store(offset, align, ptr, value): Create an f32 store, with an offset, alignment, pointer, and value.
  • f32.const(value): Create an f32 constant of a specified value.
  • f32.const_bits(value): Create an f32 constant of a specified value, reinterpreting the bits (this is useful for creating weird NaNs).
  • f32.neg(value): Create a negation of an f32.
  • f32.abs(value): Create a absolute value of an f32.
  • f32.ceil(value): Create a ceil of an f32.
  • f32.floor(value): Create a floor of an f32.
  • f32.trunc(value): Create a truncate of an f32.
  • f32.nearest(value): Create a nearest-value of an f32.
  • f32.sqrt(value): Create a square-root of an f32.
  • f32.reinterpret(value): Create a reinterpret of an i32 to an f32.
  • f32.convert_s.i32(value): Create a signed conversion of an i32 to an f32.
  • f32.convert_s.i64(value): Create a signed conversion of an i64 to an f32.
  • f32.convert_u.i32(value): Create an unsigned conversion of an i32 to an f32.
  • f32.convert_u.i64(value): Create an unsigned conversion of an i64 to an f32.
  • f32.demote(value): Create a demotion of an f64 to an f32.
  • f32.add(left, right): Create an add of two f32s.
  • f32.sub(left, right): Create a subtract of two f32s.
  • f32.mul(left, right): Create a multiply of two f32s.
  • f32.div(left, right): Create a divide of two f32s.
  • f32.copysign(left, right): Create a copysign (take magnitude of left, sign of right) of two f32s.
  • f32.min(left, right): Create a minimum on two f32s.
  • f32.max(left, right): Create a maximum on two f32s.
  • f32.eq(left, right): Create an equals on two f32s.
  • f32.ne(left, right): Create a not-equals on two f32s.
  • f32.lt(left, right): Create a less-than on two f32s.
  • f32.le(left, right): Create a less-or-equals on two f32s.
  • f32.gt(left, right): Create a greater-than on two f32s.
  • f32.ge(left, right): Create a greater-or-equals on two f32s.
• f64:
  • f64.load(offset, align, ptr): Create an f64 load, with an offset, alignment, and pointer.
  • f64.store(offset, align, ptr, value): Create an f64 store, with an offset, alignment, pointer, and value.
  • f64.const(value): Create an f64 constant of a specified value.
  • f64.const_bits(low, high): Create an f64 constant of a specified value, reinterpreting the low and high 32 bits (this is useful for creating weird NaNs).
  • f64.neg(value): Create a negation of an f64.
  • f64.abs(value): Create a absolute value of an f64.
  • f64.ceil(value): Create a ceil of an f64.
  • f64.floor(value): Create a floor of an f64.
  • f64.trunc(value): Create a truncate of an f64.
  • f64.nearest(value): Create a nearest-value of an f64.
  • f64.sqrt(value): Create a square-root of an f64.
  • f64.reinterpret(value): Create a reinterpret of an i32 to an f64.
  • f64.convert_s.i32(value): Create a signed conversion of an i32 to an f64.
  • f64.convert_s.i64(value): Create a signed conversion of an i64 to an f64.
  • f64.convert_u.i32(value): Create an unsigned conversion of an i32 to an f64.
  • f64.convert_u.i64(value): Create an unsigned conversion of an i64 to an f64.
  • f64.promote(value): Create a promotion of an f32 to an f64.
  • f64.add(left, right): Create an add of two f64s.
  • f64.sub(left, right): Create a subtract of two f64s.
  • f64.mul(left, right): Create a multiply of two f64s.
  • f64.div(left, right): Create a divide of two f64s.
  • f64.copysign(left, right): Create a copysign (take magnitude of left, sign of right) of two f64s.
  • f64.min(left, right): Create a minimum on two f64s.
  • f64.max(left, right): Create a maximum on two f64s.
  • f64.eq(left, right): Create an equals on two f64s.
  • f64.ne(left, right): Create a not-equals on two f64s.
  • f64.lt(left, right): Create a less-than on two f64s.
  • f64.le(left, right): Create a less-or-equals on two f64s.
  • f64.gt(left, right): Create a greater-than on two f64s.
  • f64.ge(left, right): Create a greater-or-equals on two f64s.

Unprefixed expressions:

• block(label, children[, type]): Create a block (a list of instructions), with an optional label, list of children and an optional result type.
• if(condition, ifTrue, ifFalse: Create an if or if-else, with a condition, code to execute if true, and optional code to execute if false.
• loop(label, body): Create a loop, with an optional label, and body.
• break(label, condition, value): Create a break, to a label, and with an optional condition, and optional value.
• switch(labels, defaultLabel, condition, value): Create a switch (aka br_table), with a list of labels, a default label, a condition, and an optional value.
• call(name, operands, type): Create a call, to a function name, with operands, and having a specific return type (note that we must specify the return type here as we may not have created the function being called yet, and we may want to optimize this function before we do so, so the API requires that each function be independent of the others, which means that we can't depend on the definition of another function).
• callImport(name, operands, type): Similar to call, but calls an imported function.
• callIndirect(target, operands, type): Similar to call, but calls indirectly, i.e., via a function pointer, so an expression replaces the name as the called value.
• getLocal(index, type): Create a get_local, for the local at the specified index, and having a specific type (the type is required for the same reasons as in call).
• setLocal(index, value): Create a set_local, for the local at the specified index, and setting the specified value.
• teeLocal(index, value): Create a tee_local, for the local at the specified index, and setting the specified value.
• getGlobal(name, type): Create a get_global, for the global with the specified name, and having the specific type (the type is required for the same reasons as in call).
• setGlobal(name, value): Create a set_global, for the global with the specified name, and setting the specified value.
• select(condition, ifTrue, ifFalse): Create a select operation, executing the condition, ifTrue, and ifFalse, and returning one of them based on the condition.
• drop(value): Create a drop of a value.
• return(value): Create a return with an optional value.
• nop(): Create a nop (no-operation).
• unreachable(): Create an unreachable (trap).

(now done with Modules, returning to the Binaryen object)

• Binaryen.readBinary(data): Reads a binary wasm module and returns a Binaryen Module object created from it.
• Binaryen.parseText(text): Parses a module in text representation and returns a Binaryen Module object created from it.
• Binaryen.emitText(expression): Returns a text representation of an individual expression, in s-expression format. Because Binaryen expression do not depend on their function or module, you can do this at any time.
• setAPITracing(on): Sets whether API tracing is on. When on, this emits C API commands for everything you do. This can be very useful for filing bug reports.
• Binaryen.Relooper(): Constructor for a Binaryen Relooper instance. This lets you provide an arbitrary CFG, and the Relooper will structure it for WebAssembly.

Relooper instances have the following methods:

• addBlock(code): Adds a new block to the CFG, containing the provided code (expression) as its body.
• addBranch(from, to, condition, code): Adds a branch from a block to another block, with a condition (or nothing, if this is the default branch to take from the origin - each block must have one such branch), and optional code to execute on the branch (useful for phis).
• addBlockWithSwitch(code, condition): Adds a new block, which ends with a switch/br_table, with provided code and condition (that determines where we go in the switch).
• addBranchForSwitch(from, to, indexes, code): Adds a branch from a block ending in a switch, to another block, using an array of indexes that determine where to go, and optional code to execute on the branch.
• renderAndDispose(entry, labelHelper, module): Renders and cleans up the Relooper instance. Call this after you have created all the blocks and branches, giving it the entry block (where control flow begins), a label helper variable (an index of a local we can use, necessary for irreducible control flow), and the module. This returns an expression - normal WebAssembly code - that you can use normally anywhere.