[wasm] Block compile/instantiate of large array buffers

third_party/WebKit/LayoutTests/fast/wasm/wasm-module-builder.js

+// Copyright 2016 the V8 project authors. All rights reserved.

[bradnelson, 2017/02/18 22:16:22]

I see this is lifted from v8.
Don't imagine we have the plumbing to share with that copy?

[Mircea Trofin, 2017/02/19 00:18:33]

We had a similar problem with the wasm structured cloning tests in 
LayoutTests. See https://codereview.chromium.org/2255673003/. Long story 
short, I chatted offline with dpranke and eisinger, and the recommendation
at the time was to follow this pattern, because LayoutTests can't reference out
of their directory. Very happy to help changing that, but 
would prefer separating the issues, unless we already have a 
mechanism in place, and given the tight schedule (we want to make 57 with 
this change).

+// 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");
+    }
+    this.body = body;
+    // Automatically add the end for the function block to the body.
+    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) {
+    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 has_names = false;
+    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) {
+          has_names = has_names || (func.name != undefined &&
+                                   func.name.length > 0);
+          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 (has_names) {
+      if (debug) print("emitting names @ " + binary.length);
+      binary.emit_section(kUnknownSectionCode, section => {
+        section.emit_string("name");
+        var count = wasm.functions.length + wasm.num_imported_funcs;
+        section.emit_u32v(count);
+        for (var i = 0; i < wasm.num_imported_funcs; i++) {
+          section.emit_u8(0); // empty string
+          section.emit_u8(0); // local names count == 0
+        }
+        for (let func of wasm.functions) {
+          var name = func.name == undefined ? "" : func.name;
+          section.emit_string(name);
+          section.emit_u8(0);  // local names count == 0
+        }
+      });
+    }
+
+    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;
+  }
+}