program.ts

/**
 * AssemblyScript's intermediate representation describing a program's elements.
 * @module program
 *//***/

import {
  CommonFlags,
  PATH_DELIMITER,
  STATIC_DELIMITER,
  INSTANCE_DELIMITER,
  GETTER_PREFIX,
  SETTER_PREFIX,
  INNER_DELIMITER,
  LIBRARY_SUBST,
  INDEX_SUFFIX,
  CommonSymbols,
  Feature,
  Target
} from "./common";

import {
  Options
} from "./compiler";

import {
  DiagnosticCode,
  DiagnosticMessage,
  DiagnosticEmitter
} from "./diagnostics";

import {
  Type,
  TypeKind,
  TypeFlags,
  Signature
} from "./types";

import {
  Node,
  NodeKind,
  Source,
  SourceKind,
  Range,
  DecoratorNode,
  DecoratorKind,
  TypeParameterNode,
  TypeNode,
  NamedTypeNode,
  FunctionTypeNode,
  ArrowKind,

  Expression,
  IdentifierExpression,
  LiteralExpression,
  LiteralKind,
  StringLiteralExpression,

  Statement,
  ClassDeclaration,
  DeclarationStatement,
  EnumDeclaration,
  EnumValueDeclaration,
  ExportMember,
  ExportStatement,
  FieldDeclaration,
  FunctionDeclaration,
  ImportDeclaration,
  ImportStatement,
  InterfaceDeclaration,
  MethodDeclaration,
  NamespaceDeclaration,
  TypeDeclaration,
  VariableDeclaration,
  VariableLikeDeclarationStatement,
  VariableStatement,

  ExportDefaultStatement,
  Token,
  ParameterNode
} from "./ast";

import {
  Module,
  FunctionRef
} from "./module";

import {
  CharCode,
  writeI8,
  writeI16,
  writeI32,
  writeF32,
  writeF64
} from "./util";

import {
  Resolver
} from "./resolver";

import {
  Flow
} from "./flow";

import {
  Parser
} from "./parser";

/** Represents a yet unresolved `import`. */
class QueuedImport {
  constructor(
    /** File being imported into. */
    public localFile: File,
    /** Identifier within the local file. */
    public localIdentifier: IdentifierExpression,
    /** Identifier within the other file. Is an `import *` if not set. */
    public foreignIdentifier: IdentifierExpression | null,
    /** Path to the other file. */
    public foreignPath: string,
    /** Alternative path to the other file. */
    public foreignPathAlt: string
  ) {}
}

/** Represents a yet unresolved `export`. */
class QueuedExport {
  constructor(
    /** Identifier within the local file. */
    public localIdentifier: IdentifierExpression,
    /** Identifier within the other file. */
    public foreignIdentifier: IdentifierExpression,
    /** Path to the other file if a re-export. */
    public foreignPath: string | null,
    /** Alternative path to the other file if a re-export. */
    public foreignPathAlt: string | null
  ) {}
}

/** Represents a yet unresolved `export *`. */
class QueuedExportStar {
  // stored in a map with localFile as the key
  constructor(
    /** Path to the other file. */
    public foreignPath: string,
    /** Alternative path to the other file. */
    public foreignPathAlt: string,
    /** Reference to the path literal for reporting. */
    public pathLiteral: StringLiteralExpression
  ) {}
}

/** Represents the kind of an operator overload. */
export enum OperatorKind {
  INVALID,

  // indexed access
  INDEXED_GET,            // a[]
  INDEXED_SET,            // a[]=b
  UNCHECKED_INDEXED_GET,  // unchecked(a[])
  UNCHECKED_INDEXED_SET,  // unchecked(a[]=b)

  // binary
  ADD,                    // a + b
  SUB,                    // a - b
  MUL,                    // a * b
  DIV,                    // a / b
  REM,                    // a % b
  POW,                    // a ** b
  BITWISE_AND,            // a & b
  BITWISE_OR,             // a | b
  BITWISE_XOR,            // a ^ b
  BITWISE_SHL,            // a << b
  BITWISE_SHR,            // a >> b
  BITWISE_SHR_U,          // a >>> b
  EQ,                     // a == b
  NE,                     // a != b
  GT,                     // a > b
  GE,                     // a >= b
  LT,                     // a < b
  LE,                     // a <= b

  // unary prefix
  PLUS,                   // +a
  MINUS,                  // -a
  NOT,                    // !a
  BITWISE_NOT,            // ~a
  PREFIX_INC,             // ++a
  PREFIX_DEC,             // --a

  // unary postfix
  POSTFIX_INC,            // a++
  POSTFIX_DEC             // a--

  // not overridable:
  // IDENTITY             // a === b
  // LOGICAL_AND          // a && b
  // LOGICAL_OR           // a || b
}

export namespace OperatorKind {

  /** Returns the operator kind represented by the specified decorator and string argument. */
  export function fromDecorator(decoratorKind: DecoratorKind, arg: string): OperatorKind {
    assert(arg.length);
    switch (decoratorKind) {
      case DecoratorKind.OPERATOR:
      case DecoratorKind.OPERATOR_BINARY: {
        switch (arg.charCodeAt(0)) {
          case CharCode.OPENBRACKET: {
            if (arg == "[]") return OperatorKind.INDEXED_GET;
            if (arg == "[]=") return OperatorKind.INDEXED_SET;
            break;
          }
          case CharCode.OPENBRACE: {
            if (arg == "{}") return OperatorKind.UNCHECKED_INDEXED_GET;
            if (arg == "{}=") return OperatorKind.UNCHECKED_INDEXED_SET;
            break;
          }
          case CharCode.PLUS: {
            if (arg == "+") return OperatorKind.ADD;
            break;
          }
          case CharCode.MINUS: {
            if (arg == "-") return OperatorKind.SUB;
            break;
          }
          case CharCode.ASTERISK: {
            if (arg == "*") return OperatorKind.MUL;
            if (arg == "**") return OperatorKind.POW;
            break;
          }
          case CharCode.SLASH: {
            if (arg == "/") return OperatorKind.DIV;
            break;
          }
          case CharCode.PERCENT: {
            if (arg == "%") return OperatorKind.REM;
            break;
          }
          case CharCode.AMPERSAND: {
            if (arg == "&") return OperatorKind.BITWISE_AND;
            break;
          }
          case CharCode.BAR: {
            if (arg == "|") return OperatorKind.BITWISE_OR;
            break;
          }
          case CharCode.CARET: {
            if (arg == "^") return OperatorKind.BITWISE_XOR;
            break;
          }
          case CharCode.EQUALS: {
            if (arg == "==") return OperatorKind.EQ;
            break;
          }
          case CharCode.EXCLAMATION: {
            if (arg == "!=") return OperatorKind.NE;
            break;
          }
          case CharCode.GREATERTHAN: {
            if (arg == ">") return OperatorKind.GT;
            if (arg == ">=") return OperatorKind.GE;
            if (arg == ">>") return OperatorKind.BITWISE_SHR;
            if (arg == ">>>") return OperatorKind.BITWISE_SHR_U;
            break;
          }
          case CharCode.LESSTHAN: {
            if (arg == "<") return OperatorKind.LT;
            if (arg == "<=") return OperatorKind.LE;
            if (arg == "<<") return OperatorKind.BITWISE_SHL;
            break;
          }
        }
        break;
      }
      case DecoratorKind.OPERATOR_PREFIX: {
        switch (arg.charCodeAt(0)) {
          case CharCode.PLUS: {
            if (arg == "+") return OperatorKind.PLUS;
            if (arg == "++") return OperatorKind.PREFIX_INC;
            break;
          }
          case CharCode.MINUS: {
            if (arg == "-") return OperatorKind.MINUS;
            if (arg == "--") return OperatorKind.PREFIX_DEC;
            break;
          }
          case CharCode.EXCLAMATION: {
            if (arg == "!") return OperatorKind.NOT;
            break;
          }
          case CharCode.TILDE: {
            if (arg == "~") return OperatorKind.BITWISE_NOT;
            break;
          }
        }
        break;
      }
      case DecoratorKind.OPERATOR_POSTFIX: {
        switch (arg.charCodeAt(0)) {
          case CharCode.PLUS: {
            if (arg == "++") return OperatorKind.POSTFIX_INC;
            break;
          }
          case CharCode.MINUS: {
            if (arg == "--") return OperatorKind.POSTFIX_DEC;
            break;
          }
        }
        break;
      }
    }
    return OperatorKind.INVALID;
  }

  /** Converts a binary operator token to the respective operator kind. */
  export function fromBinaryToken(token: Token): OperatorKind {
    switch (token) {
      case Token.PLUS:
      case Token.PLUS_EQUALS: return OperatorKind.ADD;
      case Token.MINUS:
      case Token.MINUS_EQUALS: return OperatorKind.SUB;
      case Token.ASTERISK:
      case Token.ASTERISK_EQUALS: return OperatorKind.MUL;
      case Token.SLASH:
      case Token.SLASH_EQUALS: return OperatorKind.DIV;
      case Token.PERCENT:
      case Token.PERCENT_EQUALS: return OperatorKind.REM;
      case Token.ASTERISK_ASTERISK:
      case Token.ASTERISK_ASTERISK_EQUALS: return OperatorKind.POW;
      case Token.AMPERSAND:
      case Token.AMPERSAND_EQUALS: return OperatorKind.BITWISE_AND;
      case Token.BAR:
      case Token.BAR_EQUALS: return OperatorKind.BITWISE_OR;
      case Token.CARET:
      case Token.CARET_EQUALS: return OperatorKind.BITWISE_XOR;
      case Token.LESSTHAN_LESSTHAN:
      case Token.LESSTHAN_LESSTHAN_EQUALS: return OperatorKind.BITWISE_SHL;
      case Token.GREATERTHAN_GREATERTHAN:
      case Token.GREATERTHAN_GREATERTHAN_EQUALS: return OperatorKind.BITWISE_SHR;
      case Token.GREATERTHAN_GREATERTHAN_GREATERTHAN:
      case Token.GREATERTHAN_GREATERTHAN_GREATERTHAN_EQUALS: return OperatorKind.BITWISE_SHR_U;
      case Token.EQUALS_EQUALS: return OperatorKind.EQ;
      case Token.EXCLAMATION_EQUALS: return OperatorKind.NE;
      case Token.GREATERTHAN: return OperatorKind.GT;
      case Token.GREATERTHAN_EQUALS: return OperatorKind.GE;
      case Token.LESSTHAN: return OperatorKind.LT;
      case Token.LESSTHAN_EQUALS: return OperatorKind.LE;
    }
    return OperatorKind.INVALID;
  }

  /** Converts a unary prefix operator token to the respective operator kind. */
  export function fromUnaryPrefixToken(token: Token): OperatorKind {
    switch (token) {
      case Token.PLUS: return OperatorKind.PLUS;
      case Token.MINUS: return OperatorKind.MINUS;
      case Token.EXCLAMATION: return OperatorKind.NOT;
      case Token.TILDE: return OperatorKind.BITWISE_NOT;
      case Token.PLUS_PLUS: return OperatorKind.PREFIX_INC;
      case Token.MINUS_MINUS: return OperatorKind.PREFIX_DEC;
    }
    return OperatorKind.INVALID;
  }

  /** Converts a unary postfix operator token to the respective operator kind. */
  export function fromUnaryPostfixToken(token: Token): OperatorKind {
    switch (token) {
      case Token.PLUS_PLUS: return OperatorKind.POSTFIX_INC;
      case Token.MINUS_MINUS: return OperatorKind.POSTFIX_DEC;
    }
    return OperatorKind.INVALID;
  }
}

/** Represents an AssemblyScript program. */
export class Program extends DiagnosticEmitter {

  /** Parser instance. */
  parser: Parser;
  /** Resolver instance. */
  resolver: Resolver;
  /** Array of sources. */
  sources: Source[] = [];
  /** Diagnostic offset used where successively obtaining the next diagnostic. */
  diagnosticsOffset: i32 = 0;
  /** Compiler options. */
  options: Options;
  /** Special native code source. */
  nativeSource: Source;
  /** Special native code file. */
  nativeFile: File;

  // lookup maps

  /** Files by unique internal name. */
  filesByName: Map<string,File> = new Map();
  /** Elements by unique internal name in element space. */
  elementsByName: Map<string,Element> = new Map();
  /** Elements by declaration. */
  elementsByDeclaration: Map<DeclarationStatement,DeclaredElement> = new Map();
  /** Element instances by unique internal name. */
  instancesByName: Map<string,Element> = new Map();
  /** Classes wrapping basic types like `i32`. */
  wrapperClasses: Map<Type,Class> = new Map();
  /** Managed classes contained in the program, by id. */
  managedClasses: Map<i32,Class> = new Map();
  /** A set of unique function signatures contained in the program, by id. */
  uniqueSignatures: Signature[] = new Array<Signature>(0);

  // standard references

  /** ArrayBufferView reference. */
  arrayBufferViewInstance: Class;
  /** ArrayBuffer instance reference. */
  arrayBufferInstance: Class;
  /** Array prototype reference. */
  arrayPrototype: ClassPrototype;
  /** Set prototype reference. */
  setPrototype: ClassPrototype;
  /** Map prototype reference. */
  mapPrototype: ClassPrototype;
  /** Fixed array prototype reference. */
  fixedArrayPrototype: ClassPrototype;
  /** Int8Array prototype. */
  i8ArrayPrototype: ClassPrototype;
  /** Int16Array prototype. */
  i16ArrayPrototype: ClassPrototype;
  /** Int32Array prototype. */
  i32ArrayPrototype: ClassPrototype;
  /** Int64Array prototype. */
  i64ArrayPrototype: ClassPrototype;
  /** Uint8Array prototype. */
  u8ArrayPrototype: ClassPrototype;
  /** Uint8ClampedArray prototype. */
  u8ClampedArrayPrototype: ClassPrototype;
  /** Uint16Array prototype. */
  u16ArrayPrototype: ClassPrototype;
  /** Uint32Array prototype. */
  u32ArrayPrototype: ClassPrototype;
  /** Uint64Array prototype. */
  u64ArrayPrototype: ClassPrototype;
  /** Float32Array prototype. */
  f32ArrayPrototype: ClassPrototype;
  /** Float64Array prototype. */
  f64ArrayPrototype: ClassPrototype;
  /** String instance reference. */
  stringInstance: Class;
  /** Abort function reference, if not explicitly disabled. */
  abortInstance: Function | null;

  // runtime references

  /** RT `__alloc(size: usize, id: u32): usize` */
  allocInstance: Function;
  /** RT `__realloc(ptr: usize, newSize: usize): usize` */
  reallocInstance: Function;
  /** RT `__free(ptr: usize): void` */
  freeInstance: Function;
  /** RT `__retain(ptr: usize): usize` */
  retainInstance: Function;
  /** RT `__release(ptr: usize): void` */
  releaseInstance: Function;
  /** RT `__collect(): void` */
  collectInstance: Function;
  /** RT `__visit(ptr: usize, cookie: u32): void` */
  visitInstance: Function;
  /** RT `__typeinfo(id: u32): RTTIFlags` */
  typeinfoInstance: Function;
  /** RT `__instanceof(ptr: usize, superId: u32): bool` */
  instanceofInstance: Function;
  /** RT `__allocArray(length: i32, alignLog2: usize, id: u32, data: usize = 0): usize` */
  allocArrayInstance: Function;

  /** Next class id. */
  nextClassId: u32 = 0;
  /** Next signature id. */
  nextSignatureId: i32 = 0;
  /** Constructs a new program, optionally inheriting parser diagnostics. */
  constructor(
    /** Compiler options. */
    options: Options,
    /** Shared array of diagnostic messages (emitted so far). */
    diagnostics: DiagnosticMessage[] | null = null
  ) {
    super(diagnostics);
    this.options = options;
    var nativeSource = new Source(LIBRARY_SUBST, "[native code]", SourceKind.LIBRARY_ENTRY);
    this.nativeSource = nativeSource;
    var nativeFile = new File(this, nativeSource);
    this.nativeFile = nativeFile;
    this.filesByName.set(nativeFile.internalName, nativeFile);
    this.parser = new Parser(this);
    this.resolver = new Resolver(this);
  }

  /** Obtains the source matching the specified internal path. */
  getSource(internalPath: string): string | null {
    var sources = this.sources;
    for (let i = 0; i < sources.length; ++i) {
      let source = sources[i];
      if (source.internalPath == internalPath) return source.text;
    }
    return null;
  }

  /** Writes a common runtime header to the specified buffer. */
  writeRuntimeHeader(buffer: Uint8Array, offset: i32, classInstance: Class, payloadSize: u32): void {
    // BLOCK {
    //   mmInfo: usize // WASM64 TODO
    //   gcInfo: u32
    //   rtId: u32
    //   rtSize: u32
    // }
    assert(payloadSize < (1 << 28)); // 1 bit BUFFERED + 3 bits color
    writeI32(payloadSize, buffer, offset);
    writeI32(1, buffer, offset + 4); // RC=1
    writeI32(classInstance.id, buffer, offset + 8);
    writeI32(payloadSize, buffer, offset + 12);
  }

  /** Gets the size of a runtime header. */
  get runtimeHeaderSize(): i32 {
    return 16;
  }

  /** Creates a native variable declaration. */
  makeNativeVariableDeclaration(
    /** The simple name of the variable */
    name: string,
    /** Flags indicating specific traits, e.g. `CONST`. */
    flags: CommonFlags = CommonFlags.NONE
  ): VariableDeclaration {
    var range = this.nativeSource.range;
    return Node.createVariableDeclaration(
      Node.createIdentifierExpression(name, range),
      null, null, null, flags, range
    );
  }

  /** Creates a native type declaration. */
  makeNativeTypeDeclaration(
    /** The simple name of the type. */
    name: string,
    /** Flags indicating specific traits, e.g. `GENERIC`. */
    flags: CommonFlags = CommonFlags.NONE
  ): TypeDeclaration {
    var range = this.nativeSource.range;
    var identifier = Node.createIdentifierExpression(name, range);
    return Node.createTypeDeclaration(
      identifier,
      null,
      Node.createOmittedType(range),
      null, flags, range
    );
  }

  // a dummy signature for programmatically generated native functions
  private nativeDummySignature: FunctionTypeNode | null = null;

  /** Creates a native function declaration. */
  makeNativeFunctionDeclaration(
    /** The simple name of the function. */
    name: string,
    /** Flags indicating specific traits, e.g. `DECLARE`. */
    flags: CommonFlags = CommonFlags.NONE
  ): FunctionDeclaration {
    var range = this.nativeSource.range;
    return Node.createFunctionDeclaration(
      Node.createIdentifierExpression(name, range),
      null,
      this.nativeDummySignature || (this.nativeDummySignature = Node.createFunctionType([],
        Node.createNamedType( // ^ AST signature doesn't really matter, is overridden anyway
          Node.createSimpleTypeName(CommonSymbols.void_, range),
          null, false, range
        ),
        null, false, range)
      ),
      null, null, flags, ArrowKind.NONE, range
    );
  }

  /** Creates a native namespace declaration. */
  makeNativeNamespaceDeclaration(
    /** The simple name of the namespace. */
    name: string,
    /** Flags indicating specific traits, e.g. `EXPORT`. */
    flags: CommonFlags = CommonFlags.NONE
  ): NamespaceDeclaration {
    var range = this.nativeSource.range;
    return Node.createNamespaceDeclaration(
      Node.createIdentifierExpression(name, range),
      [], null, flags, range
    );
  }

  /** Creates a native function. */
  makeNativeFunction(
    /** The simple name of the function. */
    name: string,
    /** Concrete function signature. */
    signature: Signature,
    /** Parent element, usually a file, class or namespace. */
    parent: Element = this.nativeFile,
    /** Flags indicating specific traits, e.g. `GENERIC`. */
    flags: CommonFlags = CommonFlags.NONE,
    /** Decorator flags representing built-in decorators. */
    decoratorFlags: DecoratorFlags = DecoratorFlags.NONE
  ): Function {
    return new Function(
      name,
      new FunctionPrototype(
        name,
        parent,
        this.makeNativeFunctionDeclaration(name, flags),
        decoratorFlags
      ),
      signature
    );
  }

  /** Gets the (possibly merged) program element linked to the specified declaration. */
  getElementByDeclaration(declaration: DeclarationStatement): DeclaredElement | null {
    var elementsByDeclaration = this.elementsByDeclaration;
    return elementsByDeclaration.has(declaration)
      ? elementsByDeclaration.get(declaration)!
      : null;
  }

  /** Initializes the program and its elements prior to compilation. */
  initialize(options: Options): void {
    this.options = options;

    // register native types
    this.registerNativeType(CommonSymbols.i8, Type.i8);
    this.registerNativeType(CommonSymbols.i16, Type.i16);
    this.registerNativeType(CommonSymbols.i32, Type.i32);
    this.registerNativeType(CommonSymbols.i64, Type.i64);
    this.registerNativeType(CommonSymbols.isize, options.isizeType);
    this.registerNativeType(CommonSymbols.u8, Type.u8);
    this.registerNativeType(CommonSymbols.u16, Type.u16);
    this.registerNativeType(CommonSymbols.u32, Type.u32);
    this.registerNativeType(CommonSymbols.u64, Type.u64);
    this.registerNativeType(CommonSymbols.usize, options.usizeType);
    this.registerNativeType(CommonSymbols.bool, Type.bool);
    this.registerNativeType(CommonSymbols.f32, Type.f32);
    this.registerNativeType(CommonSymbols.f64, Type.f64);
    this.registerNativeType(CommonSymbols.void_, Type.void);
    this.registerNativeType(CommonSymbols.number, Type.f64); // alias
    this.registerNativeType(CommonSymbols.boolean, Type.bool); // alias
    this.nativeFile.add(CommonSymbols.native, new TypeDefinition(
      CommonSymbols.native,
      this.nativeFile,
      this.makeNativeTypeDeclaration(CommonSymbols.native, CommonFlags.EXPORT | CommonFlags.GENERIC),
      DecoratorFlags.BUILTIN
    ));
    this.nativeFile.add(CommonSymbols.indexof, new TypeDefinition(
      CommonSymbols.indexof,
      this.nativeFile,
      this.makeNativeTypeDeclaration(CommonSymbols.indexof, CommonFlags.EXPORT | CommonFlags.GENERIC),
      DecoratorFlags.BUILTIN
    ));
    this.nativeFile.add(CommonSymbols.valueof, new TypeDefinition(
      CommonSymbols.valueof,
      this.nativeFile,
      this.makeNativeTypeDeclaration(CommonSymbols.valueof, CommonFlags.EXPORT | CommonFlags.GENERIC),
      DecoratorFlags.BUILTIN
    ));
    this.nativeFile.add(CommonSymbols.returnof, new TypeDefinition(
      CommonSymbols.returnof,
      this.nativeFile,
      this.makeNativeTypeDeclaration(CommonSymbols.returnof, CommonFlags.EXPORT | CommonFlags.GENERIC),
      DecoratorFlags.BUILTIN
    ));
    if (options.hasFeature(Feature.SIMD)) this.registerNativeType(CommonSymbols.v128, Type.v128);
    if (options.hasFeature(Feature.REFERENCE_TYPES)) this.registerNativeType(CommonSymbols.anyref, Type.anyref);

    // register compiler hints
    this.registerConstantInteger(CommonSymbols.ASC_TARGET, Type.i32,
      i64_new(options.isWasm64 ? Target.WASM64 : Target.WASM32));
    this.registerConstantInteger(CommonSymbols.ASC_NO_ASSERT, Type.bool,
      i64_new(options.noAssert ? 1 : 0, 0));
    this.registerConstantInteger(CommonSymbols.ASC_MEMORY_BASE, Type.i32,
      i64_new(options.memoryBase, 0));
    this.registerConstantInteger(CommonSymbols.ASC_OPTIMIZE_LEVEL, Type.i32,
      i64_new(options.optimizeLevelHint, 0));
    this.registerConstantInteger(CommonSymbols.ASC_SHRINK_LEVEL, Type.i32,
      i64_new(options.shrinkLevelHint, 0));

    // register feature hints
    this.registerConstantInteger(CommonSymbols.ASC_FEATURE_SIGN_EXTENSION, Type.bool,
      i64_new(options.hasFeature(Feature.SIGN_EXTENSION) ? 1 : 0, 0));
    this.registerConstantInteger(CommonSymbols.ASC_FEATURE_MUTABLE_GLOBALS, Type.bool,
      i64_new(options.hasFeature(Feature.MUTABLE_GLOBALS) ? 1 : 0, 0));
    this.registerConstantInteger(CommonSymbols.ASC_FEATURE_NONTRAPPING_F2I, Type.bool,
      i64_new(options.hasFeature(Feature.NONTRAPPING_F2I) ? 1 : 0, 0));
    this.registerConstantInteger(CommonSymbols.ASC_FEATURE_BULK_MEMORY, Type.bool,
      i64_new(options.hasFeature(Feature.BULK_MEMORY) ? 1 : 0, 0));
    this.registerConstantInteger(CommonSymbols.ASC_FEATURE_SIMD, Type.bool,
      i64_new(options.hasFeature(Feature.SIMD) ? 1 : 0, 0));
    this.registerConstantInteger(CommonSymbols.ASC_FEATURE_THREADS, Type.bool,
      i64_new(options.hasFeature(Feature.THREADS) ? 1 : 0, 0));
    this.registerConstantInteger(CommonSymbols.ASC_FEATURE_EXCEPTION_HANDLING, Type.bool,
      i64_new(options.hasFeature(Feature.EXCEPTION_HANDLING) ? 1 : 0, 0));
    this.registerConstantInteger(CommonSymbols.ASC_FEATURE_TAIL_CALLS, Type.bool,
      i64_new(options.hasFeature(Feature.TAIL_CALLS) ? 1 : 0, 0));
    this.registerConstantInteger(CommonSymbols.ASC_FEATURE_REFERENCE_TYPES, Type.bool,
      i64_new(options.hasFeature(Feature.REFERENCE_TYPES) ? 1 : 0, 0));

    // remember deferred elements
    var queuedImports = new Array<QueuedImport>();
    var queuedExports = new Map<File,Map<string,QueuedExport>>();
    var queuedExportsStar = new Map<File,QueuedExportStar[]>();
    var queuedExtends = new Array<ClassPrototype>();
    var queuedImplements = new Array<ClassPrototype>();

    // initialize relevant declaration-like statements of the entire program
    for (let i = 0, k = this.sources.length; i < k; ++i) {
      let source = this.sources[i];
      let file = new File(this, source);
      this.filesByName.set(file.internalName, file);
      let statements = source.statements;
      for (let j = 0, l = statements.length; j < l; ++j) {
        let statement = statements[j];
        switch (statement.kind) {
          case NodeKind.EXPORT: {
            this.initializeExports(<ExportStatement>statement, file, queuedExports, queuedExportsStar);
            break;
          }
          case NodeKind.EXPORTDEFAULT: {
            this.initializeExportDefault(<ExportDefaultStatement>statement, file, queuedExtends, queuedImplements);
            break;
          }
          case NodeKind.IMPORT: {
            this.initializeImports(<ImportStatement>statement, file, queuedImports, queuedExports);
            break;
          }
          case NodeKind.VARIABLE: {
            this.initializeVariables(<VariableStatement>statement, file);
            break;
          }
          case NodeKind.CLASSDECLARATION: {
            this.initializeClass(<ClassDeclaration>statement, file, queuedExtends, queuedImplements);
            break;
          }
          case NodeKind.ENUMDECLARATION: {
            this.initializeEnum(<EnumDeclaration>statement, file);
            break;
          }
          case NodeKind.FUNCTIONDECLARATION: {
            this.initializeFunction(<FunctionDeclaration>statement, file);
            break;
          }
          case NodeKind.INTERFACEDECLARATION: {
            this.initializeInterface(<InterfaceDeclaration>statement, file);
            break;
          }
          case NodeKind.NAMESPACEDECLARATION: {
            this.initializeNamespace(<NamespaceDeclaration>statement, file, queuedExtends, queuedImplements);
            break;
          }
          case NodeKind.TYPEDECLARATION: {
            this.initializeTypeDefinition(<TypeDeclaration>statement, file);
            break;
          }
        }
      }
    }

    // queued exports * should be linkable now that all files have been processed
    for (let [file, exportsStar] of queuedExportsStar) {
      for (let i = 0, k = exportsStar.length; i < k; ++i) {
        let exportStar = exportsStar[i];
        let foreignFile = this.lookupForeignFile(exportStar.foreignPath, exportStar.foreignPathAlt);
        if (!foreignFile) {
          this.error(
            DiagnosticCode.File_0_not_found,
            exportStar.pathLiteral.range, exportStar.pathLiteral.value
          );
          continue;
        }
        file.ensureExportStar(foreignFile);
      }
    }

    // queued imports should be resolvable now through traversing exports and queued exports
    for (let i = 0, k = queuedImports.length; i < k; ++i) {
      let queuedImport = queuedImports[i];
      let foreignIdentifier = queuedImport.foreignIdentifier;
      if (foreignIdentifier) { // i.e. import { foo [as bar] } from "./baz"
        let element = this.lookupForeign(
          foreignIdentifier.text,
          queuedImport.foreignPath,
          queuedImport.foreignPathAlt,
          queuedExports
        );
        if (element) {
          queuedImport.localFile.add(
            queuedImport.localIdentifier.text,
            element,
            true // isImport
          );
        } else {
          // FIXME: file not found is not reported if this happens?
          this.error(
            DiagnosticCode.Module_0_has_no_exported_member_1,
            foreignIdentifier.range, queuedImport.foreignPath, foreignIdentifier.text
          );
        }
      } else { // i.e. import * as bar from "./bar"
        let foreignFile = this.lookupForeignFile(queuedImport.foreignPath, queuedImport.foreignPathAlt);
        if (foreignFile) {
          let localFile = queuedImport.localFile;
          let localName = queuedImport.localIdentifier.text;
          localFile.add(
            localName,
            foreignFile.asImportedNamespace(
              localName,
              localFile
            ),
            true // isImport
          );
        } else {
          assert(false); // already reported by the parser not finding the file
        }
      }
    }

    // queued exports should be resolvable now that imports are finalized
    for (let [file, exports] of queuedExports) {
      for (let [exportName, queuedExport] of exports) {
        let localName = queuedExport.localIdentifier.text;
        let foreignPath = queuedExport.foreignPath;
        if (foreignPath) { // i.e. export { foo [as bar] } from "./baz"
          let element = this.lookupForeign(
            localName,
            foreignPath,
            assert(queuedExport.foreignPathAlt), // must be set if foreignPath is
            queuedExports
          );
          if (element) {
            file.ensureExport(exportName, element);
          } else {
            this.error(
              DiagnosticCode.Module_0_has_no_exported_member_1,
              queuedExport.localIdentifier.range,
              foreignPath, localName
            );
          }
        } else { // i.e. export { foo [as bar] }
          let element = file.lookupInSelf(localName);
          if (element) {
            file.ensureExport(exportName, element);
          } else {
            let globalElement = this.lookupGlobal(localName);
            if (globalElement && globalElement instanceof DeclaredElement) { // export { memory }
              file.ensureExport(exportName, <DeclaredElement>globalElement);
            } else {
              this.error(
                DiagnosticCode.Module_0_has_no_exported_member_1,
                queuedExport.foreignIdentifier.range,
                file.internalName, queuedExport.foreignIdentifier.text
              );
            }
          }
        }
      }
    }

    // register ArrayBuffer (id=0), String (id=1), ArrayBufferView (id=2)
    assert(this.nextClassId == 0);
    this.arrayBufferInstance = this.requireClass(CommonSymbols.ArrayBuffer);
    assert(this.arrayBufferInstance.id == 0);
    this.stringInstance = this.requireClass(CommonSymbols.String);
    assert(this.stringInstance.id == 1);
    this.arrayBufferViewInstance = this.requireClass(CommonSymbols.ArrayBufferView);
    assert(this.arrayBufferViewInstance.id == 2);

    // register classes backing basic types
    this.registerWrapperClass(Type.i8, CommonSymbols.I8);
    this.registerWrapperClass(Type.i16, CommonSymbols.I16);
    this.registerWrapperClass(Type.i32, CommonSymbols.I32);
    this.registerWrapperClass(Type.i64, CommonSymbols.I64);
    this.registerWrapperClass(options.isizeType, CommonSymbols.Isize);
    this.registerWrapperClass(Type.u8, CommonSymbols.U8);
    this.registerWrapperClass(Type.u16, CommonSymbols.U16);
    this.registerWrapperClass(Type.u32, CommonSymbols.U32);
    this.registerWrapperClass(Type.u64, CommonSymbols.U64);
    this.registerWrapperClass(options.usizeType, CommonSymbols.Usize);
    this.registerWrapperClass(Type.bool, CommonSymbols.Bool);
    this.registerWrapperClass(Type.f32, CommonSymbols.F32);
    this.registerWrapperClass(Type.f64, CommonSymbols.F64);
    if (options.hasFeature(Feature.SIMD)) this.registerWrapperClass(Type.v128, CommonSymbols.V128);
    if (options.hasFeature(Feature.REFERENCE_TYPES)) this.registerWrapperClass(Type.anyref, CommonSymbols.Anyref);

    // register views but don't instantiate them yet
    this.i8ArrayPrototype = <ClassPrototype>this.require(CommonSymbols.Int8Array, ElementKind.CLASS_PROTOTYPE);
    this.i16ArrayPrototype = <ClassPrototype>this.require(CommonSymbols.Int16Array, ElementKind.CLASS_PROTOTYPE);
    this.i32ArrayPrototype = <ClassPrototype>this.require(CommonSymbols.Int32Array, ElementKind.CLASS_PROTOTYPE);
    this.i64ArrayPrototype = <ClassPrototype>this.require(CommonSymbols.Int64Array, ElementKind.CLASS_PROTOTYPE);
    this.u8ArrayPrototype = <ClassPrototype>this.require(CommonSymbols.Uint8Array, ElementKind.CLASS_PROTOTYPE);
    this.u8ClampedArrayPrototype = <ClassPrototype>this.require(CommonSymbols.Uint8ClampedArray, ElementKind.CLASS_PROTOTYPE);
    this.u16ArrayPrototype = <ClassPrototype>this.require(CommonSymbols.Uint16Array, ElementKind.CLASS_PROTOTYPE);
    this.u32ArrayPrototype = <ClassPrototype>this.require(CommonSymbols.Uint32Array, ElementKind.CLASS_PROTOTYPE);
    this.u64ArrayPrototype = <ClassPrototype>this.require(CommonSymbols.Uint64Array, ElementKind.CLASS_PROTOTYPE);
    this.f32ArrayPrototype = <ClassPrototype>this.require(CommonSymbols.Float32Array, ElementKind.CLASS_PROTOTYPE);
    this.f64ArrayPrototype = <ClassPrototype>this.require(CommonSymbols.Float64Array, ElementKind.CLASS_PROTOTYPE);

    // resolve base prototypes of derived classes
    var resolver = this.resolver;
    for (let i = 0, k = queuedExtends.length; i < k; ++i) {
      let thisPrototype = queuedExtends[i];
      let extendsNode = assert(thisPrototype.extendsNode); // must be present if in queuedExtends
      let baseElement = resolver.resolveTypeName(extendsNode.name, thisPrototype.parent); // reports
      if (!baseElement) continue;
      if (baseElement.kind == ElementKind.CLASS_PROTOTYPE) {
        let basePrototype = <ClassPrototype>baseElement;
        if (basePrototype.hasDecorator(DecoratorFlags.SEALED)) {
          this.error(
            DiagnosticCode.Class_0_is_sealed_and_cannot_be_extended,
            extendsNode.range, (<ClassPrototype>baseElement).identifierNode.text
          );
        }
        if (
          basePrototype.hasDecorator(DecoratorFlags.UNMANAGED) !=
          thisPrototype.hasDecorator(DecoratorFlags.UNMANAGED)
        ) {
          this.error(
            DiagnosticCode.Unmanaged_classes_cannot_extend_managed_classes_and_vice_versa,
            Range.join(thisPrototype.identifierNode.range, extendsNode.range)
          );
        }
        thisPrototype.basePrototype = basePrototype;
      } else {
        this.error(
          DiagnosticCode.A_class_may_only_extend_another_class,
          extendsNode.range
        );
      }
    }

    // set up global aliases
    {
      let globalAliases = options.globalAliases;
      if (globalAliases) {
        for (let [alias, name] of globalAliases) {
          if (!name.length) continue; // explicitly disabled
          let firstChar = name.charCodeAt(0);
          if (firstChar >= CharCode._0 && firstChar <= CharCode._9) {
            this.registerConstantInteger(alias, Type.i32, i64_new(<i32>parseInt(name, 10)));
          } else {
            let elementsByName = this.elementsByName;
            let element = elementsByName.get(name);
            if (element) {
              if (elementsByName.has(alias)) throw new Error("duplicate global element: " + name);
              elementsByName.set(alias, element);
            }
            else throw new Error("no such global element: " + name);
          }
        }
      }
    }

    // register stdlib components
    this.arrayPrototype = <ClassPrototype>this.require(CommonSymbols.Array, ElementKind.CLASS_PROTOTYPE);
    this.fixedArrayPrototype = <ClassPrototype>this.require(CommonSymbols.FixedArray, ElementKind.CLASS_PROTOTYPE);
    this.setPrototype = <ClassPrototype>this.require(CommonSymbols.Set, ElementKind.CLASS_PROTOTYPE);
    this.mapPrototype = <ClassPrototype>this.require(CommonSymbols.Map, ElementKind.CLASS_PROTOTYPE);
    this.abortInstance = this.lookupFunction(CommonSymbols.abort); // can be disabled
    this.allocInstance = this.requireFunction(CommonSymbols.alloc);
    this.reallocInstance = this.requireFunction(CommonSymbols.realloc);
    this.freeInstance = this.requireFunction(CommonSymbols.free);
    this.retainInstance = this.requireFunction(CommonSymbols.retain);
    this.releaseInstance = this.requireFunction(CommonSymbols.release);
    this.collectInstance = this.requireFunction(CommonSymbols.collect);
    this.typeinfoInstance = this.requireFunction(CommonSymbols.typeinfo);
    this.instanceofInstance = this.requireFunction(CommonSymbols.instanceof_);
    this.visitInstance = this.requireFunction(CommonSymbols.visit);
    this.allocArrayInstance = this.requireFunction(CommonSymbols.allocArray);

    // mark module exports, i.e. to apply proper wrapping behavior on the boundaries
    for (let file of this.filesByName.values()) {
      let exports = file.exports;
      if (exports !== null && file.source.sourceKind == SourceKind.USER_ENTRY) {
        for (let element of exports.values()) this.markModuleExport(element);
      }
    }
  }

  /** Requires that a global library element of the specified kind is present and returns it. */
  private require(name: string, kind: ElementKind): Element {
    var element = this.lookupGlobal(name);
    if (!element) throw new Error("missing " + name);
    if (element.kind != kind) throw new Error("unexpected " + name);
    return element;
  }

  /** Requires that a non-generic global class is present and returns it. */
  private requireClass(name: string): Class {
    var prototype = this.require(name, ElementKind.CLASS_PROTOTYPE);
    var resolved = this.resolver.resolveClass(<ClassPrototype>prototype, null);