// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Used for encoding f32 and double constants to bits.
let __buffer = new ArrayBuffer(8);
let byte_view = new Int8Array(__buffer);
let f32_view = new Float32Array(__buffer);
let f64_view = new Float64Array(__buffer);
class Binary extends Array {
emit_u8(val) {
this.push(val);
}
emit_u16(val) {
this.push(val & 0xff);
this.push((val >> 8) & 0xff);
}
emit_u32(val) {
this.push(val & 0xff);
this.push((val >> 8) & 0xff);
this.push((val >> 16) & 0xff);
this.push((val >> 24) & 0xff);
}
emit_u32v(val) {
while (true) {
let v = val & 0xff;
val = val >>> 7;
if (val == 0) {
this.push(v);
break;
}
this.push(v | 0x80);
}
}
emit_bytes(data) {
for (let i = 0; i < data.length; i++) {
this.push(data[i] & 0xff);
}
}
emit_string(string) {
// When testing illegal names, we pass a byte array directly.
if (string instanceof Array) {
this.emit_u32v(string.length);
this.emit_bytes(string);
return;
}
// This is the hacky way to convert a JavaScript string to a UTF8 encoded
// string only containing single-byte characters.
let string_utf8 = unescape(encodeURIComponent(string));
this.emit_u32v(string_utf8.length);
for (let i = 0; i < string_utf8.length; i++) {
this.emit_u8(string_utf8.charCodeAt(i));
}
}
emit_header() {
this.push(kWasmH0, kWasmH1, kWasmH2, kWasmH3,
kWasmV0, kWasmV1, kWasmV2, kWasmV3);
}
emit_section(section_code, content_generator) {
// Emit section name.
this.emit_u8(section_code);
// Emit the section to a temporary buffer: its full length isn't know yet.
let section = new Binary;
content_generator(section);
// Emit section length.
this.emit_u32v(section.length);
// Copy the temporary buffer.
for (var i = 0; i < section.length; i++) this.push(section[i]);
}
}
class FunctionBodyBuilder extends Binary {
get_local(index) {
this.emit_u8(kExprGetLocal);
this.emit_u32v(index);
return this;
}
i32_const(k) {
this.emit_u8(kExprI32Const);
this.emit_u32v(k);
return this;
}
i32_load(args) {
let align = args != undefined && args.align != undefined ? args.align : 1;
let offset =
args != undefined && args.offset != undefined ? args.offset : 0;
this.emit_u8(kExprI32LoadMem);
this.emit_u32v(align);
this.emit_u32v(offset);
return this;
}
i32_store(args) {
let align = args != undefined && args.align != undefined ? args.align : 1;
let offset =
args != undefined && args.offset != undefined ? args.offset : 0;
this.emit_u8(kExprI32StoreMem);
this.emit_u32v(align);
this.emit_u32v(offset);
return this;
}
grow_memory() {
this.emit_u8(kExprGrowMemory);
this.emit_u8(0);
return this;
}
end() {
this.emit_u8(kExprEnd);
}
}
class WasmFunctionBuilder {
constructor(module, name, type_index) {
this.module = module;
this.name = name;
this.type_index = type_index;
this.body = new FunctionBodyBuilder;
}
numLocalNames() {
if (this.local_names === undefined) return 0;
let num_local_names = 0;
for (let loc_name of this.local_names) {
if (loc_name !== undefined) ++num_local_names;
}
return num_local_names;
}
exportAs(name) {
this.module.addExport(name, this.index);
return this;
}
exportFunc() {
this.exportAs(this.name);
return this;
}
addBody(body) {
for (let b of body) {
if (typeof b !== 'number' || (b & (~0xFF)) !== 0 )
throw new Error('invalid body (entries must be 8 bit values): ' + body);
}
this.body = body.slice();
// Automatically add the end for the function block to the body.
this.body.push(kExprEnd);
return this;
}
addBodyWithEnd(body) {
this.body = body;
return this;
}
addLocals(locals, names) {
this.locals = locals;
this.local_names = names;
return this;
}
end() {
return this.module;
}
}
class WasmGlobalBuilder {
constructor(module, type, mutable) {
this.module = module;
this.type = type;
this.mutable = mutable;
this.init = 0;
}
exportAs(name) {
this.module.exports.push({name: name, kind: kExternalGlobal,
index: this.index});
return this;
}
}
class WasmModuleBuilder {
constructor() {
this.types = [];
this.imports = [];
this.exports = [];
this.globals = [];
this.exceptions = [];
this.functions = [];
this.function_table = [];
this.function_table_length = 0;
this.function_table_inits = [];
this.segments = [];
this.explicit = [];
this.num_imported_funcs = 0;
this.num_imported_globals = 0;
return this;
}
addStart(start_index) {
this.start_index = start_index;
return this;
}
addMemory(min, max, exp) {
this.memory = {min: min, max: max, exp: exp};
return this;
}
addExplicitSection(bytes) {
this.explicit.push(bytes);
return this;
}
stringToBytes(name) {
var result = new Binary();
result.emit_u32v(name.length);
for (var i = 0; i < name.length; i++) {
result.emit_u8(name.charCodeAt(i));
}
return result;
}
addCustomSection(name, bytes) {
name = this.stringToBytes(name);
var length = new Binary();
length.emit_u32v(name.length + bytes.length);
this.explicit.push([0, ...length, ...name, ...bytes]);
}
addType(type) {
this.types.push(type);
var pl = type.params.length; // should have params
var rl = type.results.length; // should have results
return this.types.length - 1;
}
addGlobal(local_type, mutable) {
let glob = new WasmGlobalBuilder(this, local_type, mutable);
glob.index = this.globals.length + this.num_imported_globals;
this.globals.push(glob);
return glob;
}
addException(type) {
if (type.results.length != 0)
throw new Error('Invalid exception signature: ' + type);
this.exceptions.push(type);
return this.exceptions.length - 1;
}
addFunction(name, type) {
let type_index = (typeof type) == "number" ? type : this.addType(type);
let func = new WasmFunctionBuilder(this, name, type_index);
func.index = this.functions.length + this.num_imported_funcs;
this.functions.push(func);
return func;
}
addImport(module = "", name, type) {
let type_index = (typeof type) == "number" ? type : this.addType(type);
this.imports.push({module: module, name: name, kind: kExternalFunction,
type: type_index});
return this.num_imported_funcs++;
}
addImportedGlobal(module = "", name, type) {
let o = {module: module, name: name, kind: kExternalGlobal, type: type,
mutable: false}
this.imports.push(o);
return this.num_imported_globals++;
}
addImportedMemory(module = "", name, initial = 0, maximum) {
let o = {module: module, name: name, kind: kExternalMemory,
initial: initial, maximum: maximum};
this.imports.push(o);
return this;
}
addImportedTable(module = "", name, initial, maximum) {
let o = {module: module, name: name, kind: kExternalTable, initial: initial,
maximum: maximum};
this.imports.push(o);
}
addExport(name, index) {
this.exports.push({name: name, kind: kExternalFunction, index: index});
return this;
}
addExportOfKind(name, kind, index) {
this.exports.push({name: name, kind: kind, index: index});
return this;
}
addDataSegment(addr, data, is_global = false) {
this.segments.push({addr: addr, data: data, is_global: is_global});
return this.segments.length - 1;
}
exportMemoryAs(name) {
this.exports.push({name: name, kind: kExternalMemory, index: 0});
}
addFunctionTableInit(base, is_global, array, is_import = false) {
this.function_table_inits.push({base: base, is_global: is_global,
array: array});
if (!is_global) {
var length = base + array.length;
if (length > this.function_table_length && !is_import) {
this.function_table_length = length;
}
}
return this;
}
appendToTable(array) {
for (let n of array) {
if (typeof n != 'number')
throw new Error('invalid table (entries have to be numbers): ' + array);
}
return this.addFunctionTableInit(this.function_table.length, false, array);
}
setFunctionTableLength(length) {
this.function_table_length = length;
return this;
}
setName(name) {
this.name = name;
return this;
}
toArray(debug = false) {
let binary = new Binary;
let wasm = this;
// Add header
binary.emit_header();
// Add type section
if (wasm.types.length > 0) {
if (debug) print("emitting types @ " + binary.length);
binary.emit_section(kTypeSectionCode, section => {
section.emit_u32v(wasm.types.length);
for (let type of wasm.types) {
section.emit_u8(kWasmFunctionTypeForm);
section.emit_u32v(type.params.length);
for (let param of type.params) {
section.emit_u8(param);
}
section.emit_u32v(type.results.length);
for (let result of type.results) {
section.emit_u8(result);
}
}
});
}
// Add imports section
if (wasm.imports.length > 0) {
if (debug) print("emitting imports @ " + binary.length);
binary.emit_section(kImportSectionCode, section => {
section.emit_u32v(wasm.imports.length);
for (let imp of wasm.imports) {
section.emit_string(imp.module);
section.emit_string(imp.name || '');
section.emit_u8(imp.kind);
if (imp.kind == kExternalFunction) {
section.emit_u32v(imp.type);
} else if (imp.kind == kExternalGlobal) {
section.emit_u32v(imp.type);
section.emit_u8(imp.mutable);
} else if (imp.kind == kExternalMemory) {
var has_max = (typeof imp.maximum) != "undefined";
section.emit_u8(has_max ? 1 : 0); // flags
section.emit_u32v(imp.initial); // initial
if (has_max) section.emit_u32v(imp.maximum); // maximum
} else if (imp.kind == kExternalTable) {
section.emit_u8(kWasmAnyFunctionTypeForm);
var has_max = (typeof imp.maximum) != "undefined";
section.emit_u8(has_max ? 1 : 0); // flags
section.emit_u32v(imp.initial); // initial
if (has_max) section.emit_u32v(imp.maximum); // maximum
} else {
throw new Error("unknown/unsupported import kind " + imp.kind);
}
}
});
}
// Add functions declarations
if (wasm.functions.length > 0) {
if (debug) print("emitting function decls @ " + binary.length);
binary.emit_section(kFunctionSectionCode, section => {
section.emit_u32v(wasm.functions.length);
for (let func of wasm.functions) {
section.emit_u32v(func.type_index);
}
});
}
// Add function_table.
if (wasm.function_table_length > 0) {
if (debug) print("emitting table @ " + binary.length);
binary.emit_section(kTableSectionCode, section => {
section.emit_u8(1); // one table entry
section.emit_u8(kWasmAnyFunctionTypeForm);
section.emit_u8(1);
section.emit_u32v(wasm.function_table_length);
section.emit_u32v(wasm.function_table_length);
});
}
// Add memory section
if (wasm.memory !== undefined) {
if (debug) print("emitting memory @ " + binary.length);
binary.emit_section(kMemorySectionCode, section => {
section.emit_u8(1); // one memory entry
const has_max = wasm.memory.max !== undefined;
section.emit_u32v(has_max ? kResizableMaximumFlag : 0);
section.emit_u32v(wasm.memory.min);
if (has_max) section.emit_u32v(wasm.memory.max);
});
}
// Add global section.
if (wasm.globals.length > 0) {
if (debug) print ("emitting globals @ " + binary.length);
binary.emit_section(kGlobalSectionCode, section => {
section.emit_u32v(wasm.globals.length);
for (let global of wasm.globals) {
section.emit_u8(global.type);
section.emit_u8(global.mutable);
if ((typeof global.init_index) == "undefined") {
// Emit a constant initializer.
switch (global.type) {
case kWasmI32:
section.emit_u8(kExprI32Const);
section.emit_u32v(global.init);
break;
case kWasmI64:
section.emit_u8(kExprI64Const);
section.emit_u32v(global.init);
break;
case kWasmF32:
section.emit_u8(kExprF32Const);
f32_view[0] = global.init;
section.emit_u8(byte_view[0]);
section.emit_u8(byte_view[1]);
section.emit_u8(byte_view[2]);
section.emit_u8(byte_view[3]);
break;
case kWasmF64:
section.emit_u8(kExprF64Const);
f64_view[0] = global.init;
section.emit_u8(byte_view[0]);
section.emit_u8(byte_view[1]);
section.emit_u8(byte_view[2]);
section.emit_u8(byte_view[3]);
section.emit_u8(byte_view[4]);
section.emit_u8(byte_view[5]);
section.emit_u8(byte_view[6]);
section.emit_u8(byte_view[7]);
break;
}
} else {
// Emit a global-index initializer.
section.emit_u8(kExprGetGlobal);
section.emit_u32v(global.init_index);
}
section.emit_u8(kExprEnd); // end of init expression
}
});
}
// Add export table.
var mem_export = (wasm.memory !== undefined && wasm.memory.exp);
var exports_count = wasm.exports.length + (mem_export ? 1 : 0);
if (exports_count > 0) {
if (debug) print("emitting exports @ " + binary.length);
binary.emit_section(kExportSectionCode, section => {
section.emit_u32v(exports_count);
for (let exp of wasm.exports) {
section.emit_string(exp.name);
section.emit_u8(exp.kind);
section.emit_u32v(exp.index);
}
if (mem_export) {
section.emit_string("memory");
section.emit_u8(kExternalMemory);
section.emit_u8(0);
}
});
}
// Add start function section.
if (wasm.start_index !== undefined) {
if (debug) print("emitting start function @ " + binary.length);
binary.emit_section(kStartSectionCode, section => {
section.emit_u32v(wasm.start_index);
});
}
// Add table elements.
if (wasm.function_table_inits.length > 0) {
if (debug) print("emitting table @ " + binary.length);
binary.emit_section(kElementSectionCode, section => {
var inits = wasm.function_table_inits;
section.emit_u32v(inits.length);
for (let init of inits) {
section.emit_u8(0); // table index
if (init.is_global) {
section.emit_u8(kExprGetGlobal);
} else {
section.emit_u8(kExprI32Const);
}
section.emit_u32v(init.base);
section.emit_u8(kExprEnd);
section.emit_u32v(init.array.length);
for (let index of init.array) {
section.emit_u32v(index);
}
}
});
}
// Add exceptions.
if (wasm.exceptions.length > 0) {
if (debug) print("emitting exceptions @ " + binary.length);
binary.emit_section(kExceptionSectionCode, section => {
section.emit_u32v(wasm.exceptions.length);
for (let type of wasm.exceptions) {
section.emit_u32v(type.params.length);
for (let param of type.params) {
section.enit_u8(param);
}
}
});
}
// Add function bodies.
if (wasm.functions.length > 0) {
// emit function bodies
if (debug) print("emitting code @ " + binary.length);
binary.emit_section(kCodeSectionCode, section => {
section.emit_u32v(wasm.functions.length);
for (let func of wasm.functions) {
// Function body length will be patched later.
let local_decls = [];
let l = func.locals;
if (l !== undefined) {
let local_decls_count = 0;
if (l.i32_count > 0) {
local_decls.push({count: l.i32_count, type: kWasmI32});
}
if (l.i64_count > 0) {
local_decls.push({count: l.i64_count, type: kWasmI64});
}
if (l.f32_count > 0) {
local_decls.push({count: l.f32_count, type: kWasmF32});
}
if (l.f64_count > 0) {
local_decls.push({count: l.f64_count, type: kWasmF64});
}
}
let header = new Binary;
header.emit_u32v(local_decls.length);
for (let decl of local_decls) {
header.emit_u32v(decl.count);
header.emit_u8(decl.type);
}
section.emit_u32v(header.length + func.body.length);
section.emit_bytes(header);
section.emit_bytes(func.body);
}
});
}
// Add data segments.
if (wasm.segments.length > 0) {
if (debug) print("emitting data segments @ " + binary.length);
binary.emit_section(kDataSectionCode, section => {
section.emit_u32v(wasm.segments.length);
for (let seg of wasm.segments) {
section.emit_u8(0); // linear memory index 0
if (seg.is_global) {
// initializer is a global variable
section.emit_u8(kExprGetGlobal);
section.emit_u32v(seg.addr);
} else {
// initializer is a constant
section.emit_u8(kExprI32Const);
section.emit_u32v(seg.addr);
}
section.emit_u8(kExprEnd);
section.emit_u32v(seg.data.length);
section.emit_bytes(seg.data);
}
});
}
// Add any explicitly added sections
for (let exp of wasm.explicit) {
if (debug) print("emitting explicit @ " + binary.length);
binary.emit_bytes(exp);
}
// Add names.
let num_function_names = 0;
let num_functions_with_local_names = 0;
for (let func of wasm.functions) {
if (func.name !== undefined) ++num_function_names;
if (func.numLocalNames() > 0) ++num_functions_with_local_names;
}
if (num_function_names > 0 || num_functions_with_local_names > 0 ||
wasm.name !== undefined) {
if (debug) print('emitting names @ ' + binary.length);
binary.emit_section(kUnknownSectionCode, section => {
section.emit_string('name');
// Emit module name.
if (wasm.name !== undefined) {
section.emit_section(kModuleNameCode, name_section => {
name_section.emit_string(wasm.name);
});
}
// Emit function names.
if (num_function_names > 0) {
section.emit_section(kFunctionNamesCode, name_section => {
name_section.emit_u32v(num_function_names);
for (let func of wasm.functions) {
if (func.name === undefined) continue;
name_section.emit_u32v(func.index);
name_section.emit_string(func.name);
}
});
}
// Emit local names.
if (num_functions_with_local_names > 0) {
section.emit_section(kLocalNamesCode, name_section => {
name_section.emit_u32v(num_functions_with_local_names);
for (let func of wasm.functions) {
if (func.numLocalNames() == 0) continue;
name_section.emit_u32v(func.index);
name_section.emit_u32v(func.numLocalNames());
for (let i = 0; i < func.local_names.length; ++i) {
if (func.local_names[i] === undefined) continue;
name_section.emit_u32v(i);
name_section.emit_string(func.local_names[i]);
}
}
});
}
});
}
return binary;
}
toBuffer(debug = false) {
let bytes = this.toArray(debug);
let buffer = new ArrayBuffer(bytes.length);
let view = new Uint8Array(buffer);
for (let i = 0; i < bytes.length; i++) {
let val = bytes[i];
if ((typeof val) == "string") val = val.charCodeAt(0);
view[i] = val | 0;
}
return buffer;
}
instantiate(ffi) {
let module = new WebAssembly.Module(this.toBuffer());
let instance = new WebAssembly.Instance(module, ffi);
return instance;
}
toModule(debug = false) {
return new WebAssembly.Module(this.toBuffer(debug));
}
}
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