v8/test/mjsunit/wasm/wasm-module-builder.js
Clemens Hammacher 1a73f73b3b [wasm] Implement extensible name section
The format of the name section changed recently. It now contains
subsections of different type (currently for function names or local
variable names).
This CL changes our internal wasm module builders (in JS and C++) to
emit this new format, and changes the decoder to understand it.
We currently only parse the function name section, and ignore names of
local variables. I will later extend this to parse local variable names
when needed for debugging.

R=ahaas@chromium.org, rossberg@chromium.org
BUG=v8:6222

Change-Id: I2627160c25c9209a3f09abe0b88941ec48b24434
Reviewed-on: https://chromium-review.googlesource.com/470247
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Andreas Rossberg <rossberg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44492}
2017-04-07 16:31:47 +00:00

585 lines
17 KiB
JavaScript

// Copyright 2016 the V8 project authors. All rights reserved.
// 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.
this.push(...section);
}
}
class WasmFunctionBuilder {
constructor(module, name, type_index) {
this.module = module;
this.name = name;
this.type_index = type_index;
this.body = [];
}
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')
throw new Error('invalid body (entries have to be numbers): ' + 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) {
this.locals = locals;
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.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) {
// TODO: canonicalize types?
this.types.push(type);
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;
}
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;
}
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
let num_function_names = 0;
let names = false;
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) {
if (func.name !== undefined) {
++num_function_names;
}
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
section.emit_u32v(kResizableMaximumFlag);
section.emit_u32v(wasm.memory.min);
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);
section.emit_u8(0); // table index
for (let init of inits) {
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 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 function names.
if (num_function_names > 0) {
if (debug) print('emitting names @ ' + binary.length);
binary.emit_section(kUnknownSectionCode, section => {
section.emit_string('name');
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);
}
});
});
}
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;
}
}