Omit full collection support if the entire program is acyclic (#1071)

Author: dcodeIO

cli/asc.js

@@ -224,6 +224,7 @@ exports.main = function main(argv, options, callback) {
   assemblyscript.setMemoryBase(compilerOptions, args.memoryBase >>> 0);
   assemblyscript.setSourceMap(compilerOptions, args.sourceMap != null);
   assemblyscript.setNoUnsafe(compilerOptions, args.noUnsafe);
+  assemblyscript.setPedantic(compilerOptions, args.pedantic);
 
   // Initialize default aliases
   assemblyscript.setGlobalAlias(compilerOptions, "Math", "NativeMath");

cli/asc.json

@@ -224,6 +224,11 @@
     "description": "Specifies the path to a custom transform to 'require'.",
     "type": "S"
   },
+  "pedantic": {
+    "description": "Make yourself sad for no good reason.",
+    "type": "b",
+    "default": false
+  },
   "traceResolution": {
     "description": "Enables tracing of package resolution.",
     "type": "b",

src/builtins.ts

@@ -63,7 +63,8 @@ import {
   Field,
   Global,
   DecoratorFlags,
-  Element
+  Element,
+  Class
 } from "./program";
 
 import {
@@ -4733,7 +4734,8 @@ export function compileVisitGlobals(compiler: Compiler): void {
   var nativeSizeType = compiler.options.nativeSizeType;
   var visitInstance = assert(compiler.program.visitInstance);
 
-  compiler.compileFunction(visitInstance);
+  // this function is @lazy: make sure it exists
+  compiler.compileFunction(visitInstance, true);
 
   for (let element of compiler.program.elementsByName.values()) {
     if (element.kind != ElementKind.GLOBAL) continue;
@@ -4794,6 +4796,9 @@ export function compileVisitMembers(compiler: Compiler): void {
   var blocks = new Array<RelooperBlockRef>();
   var relooper = Relooper.create(module);
 
+  // this function is @lazy: make sure it exists
+  compiler.compileFunction(visitInstance, true);
+
   var outer = relooper.addBlockWithSwitch(
     module.nop(),
     module.load(nativeSizeSize, false,

src/compiler.ts

@@ -210,6 +210,8 @@ export class Options {
   features: Feature = Feature.MUTABLE_GLOBALS;
   /** If true, disallows unsafe features in user code. */
   noUnsafe: bool = false;
+  /** If true, enables pedantic diagnostics. */
+  pedantic: bool = false;
 
   /** Hinted optimize level. Not applied by the compiler itself. */
   optimizeLevelHint: i32 = 0;
@@ -236,6 +238,11 @@ export class Options {
     return this.target == Target.WASM64 ? NativeType.I64 : NativeType.I32;
   }
 
+  /** Gets if any optimizations will be performed. */
+  get willOptimize(): bool {
+    return this.optimizeLevelHint > 0 || this.shrinkLevelHint > 0;
+  }
+
   /** Tests if a specific feature is activated. */
   hasFeature(feature: Feature): bool {
     return (this.features & feature) != 0;
@@ -322,6 +329,8 @@ export class Compiler extends DiagnosticEmitter {
   skippedAutoreleases: Set<ExpressionRef> = new Set();
   /** Current inline functions stack. */
   inlineStack: Function[] = [];
+  /** Lazily compiled library functions. */
+  lazyLibraryFunctions: Set<Function> = new Set();
 
   /** Compiles a {@link Program} to a {@link Module} using the specified options. */
   static compile(program: Program): Module {
@@ -387,7 +396,7 @@ export class Compiler extends DiagnosticEmitter {
       }
     }
 
-    // compile the start function if not empty or explicitly requested
+    // compile the start function if not empty or if explicitly requested
     var startIsEmpty = !startFunctionBody.length;
     var explicitStart = options.explicitStart;
     if (!startIsEmpty || explicitStart) {
@@ -414,11 +423,39 @@ export class Compiler extends DiagnosticEmitter {
       else module.addFunctionExport(startFunctionInstance.internalName, ExportNames.start);
     }
 
-    // compile runtime features
-    if (this.runtimeFeatures & RuntimeFeatures.visitGlobals) compileVisitGlobals(this);
-    if (this.runtimeFeatures & RuntimeFeatures.visitMembers) compileVisitMembers(this);
+    // check if the entire program is acyclic
+    var cyclicClasses = program.findCyclicClasses();
+    if (cyclicClasses.size) {
+      if (options.pedantic) {
+        for (let classInstance of cyclicClasses) {
+          this.info(
+            DiagnosticCode.Type_0_is_cyclic_Module_will_include_deferred_garbage_collection,
+            classInstance.identifierNode.range, classInstance.internalName
+          );
+        }
+      }
+    } else {
+      program.registerConstantInteger("__GC_ALL_ACYCLIC", Type.bool, i64_new(1, 0));
+    }
+
+    // compile lazy library functions
+    var lazyLibraryFunctions = this.lazyLibraryFunctions;
+    do {
+      let functionsToCompile = new Array<Function>();
+      for (let instance of lazyLibraryFunctions) {
+        functionsToCompile.push(instance);
+      }
+      lazyLibraryFunctions.clear();
+      for (let i = 0, k = functionsToCompile.length; i < k; ++i) {
+        this.compileFunction(unchecked(functionsToCompile[i]), true);
+      }
+    } while (lazyLibraryFunctions.size);
+
+    // finalize runtime features
     module.removeGlobal(BuiltinNames.rtti_base);
     if (this.runtimeFeatures & RuntimeFeatures.RTTI) compileRTTI(this);
+    if (this.runtimeFeatures & RuntimeFeatures.visitGlobals) compileVisitGlobals(this);
+    if (this.runtimeFeatures & RuntimeFeatures.visitMembers) compileVisitMembers(this);
 
     // update the heap base pointer
     var memoryOffset = this.memoryOffset;
@@ -464,8 +501,24 @@ export class Compiler extends DiagnosticEmitter {
     module.setFunctionTable(1 + functionTable.length, Module.UNLIMITED_TABLE, functionTable, module.i32(1));
 
     // import and/or export table if requested (default table is named '0' by Binaryen)
-    if (options.importTable) module.addTableImport("0", "env", "table");
-    if (options.exportTable) module.addTableExport("0", ExportNames.table);
+    if (options.importTable) {
+      module.addTableImport("0", "env", "table");
+      if (options.pedantic && options.willOptimize) {
+        this.warning(
+          DiagnosticCode.Importing_the_table_disables_some_indirect_call_optimizations,
+          null
+        );
+      }
+    }
+    if (options.exportTable) {
+      module.addTableExport("0", ExportNames.table);
+      if (options.pedantic && options.willOptimize) {
+        this.warning(
+          DiagnosticCode.Exporting_the_table_disables_some_indirect_call_optimizations,
+          null
+        );
+      }
+    }
 
     // set up module exports
     for (let file of this.program.filesByName.values()) {
@@ -1101,11 +1154,15 @@ export class Compiler extends DiagnosticEmitter {
     forceStdAlternative: bool = false
   ): bool {
     if (instance.is(CommonFlags.COMPILED)) return true;
-    if (instance.hasDecorator(DecoratorFlags.BUILTIN)) {
-      if (!forceStdAlternative) return true;
+    if (!forceStdAlternative) {
+      if (instance.hasDecorator(DecoratorFlags.BUILTIN)) return true;
+      if (instance.hasDecorator(DecoratorFlags.LAZY)) {
+        this.lazyLibraryFunctions.add(instance);
+        return true;
+      }
     }
 
-    var previousType = this.currentType; // remember to retain it if compiling a function lazily
+    var previousType = this.currentType;
     instance.set(CommonFlags.COMPILED);
 
     var module = this.module;

src/diagnosticMessages.generated.ts

@@ -37,6 +37,9 @@ export enum DiagnosticCode {
   _0_must_be_a_power_of_two = 223,
   _0_is_not_a_valid_operator = 224,
   Expression_cannot_be_represented_by_a_type = 225,
+  Type_0_is_cyclic_Module_will_include_deferred_garbage_collection = 900,
+  Importing_the_table_disables_some_indirect_call_optimizations = 901,
+  Exporting_the_table_disables_some_indirect_call_optimizations = 902,
   Unterminated_string_literal = 1002,
   Identifier_expected = 1003,
   _0_expected = 1005,
@@ -181,6 +184,9 @@ export function diagnosticCodeToString(code: DiagnosticCode): string {
     case 223: return "'{0}' must be a power of two.";
     case 224: return "'{0}' is not a valid operator.";
     case 225: return "Expression cannot be represented by a type.";
+    case 900: return "Type '{0}' is cyclic. Module will include deferred garbage collection.";
+    case 901: return "Importing the table disables some indirect call optimizations.";
+    case 902: return "Exporting the table disables some indirect call optimizations.";
     case 1002: return "Unterminated string literal.";
     case 1003: return "Identifier expected.";
     case 1005: return "'{0}' expected.";

src/diagnosticMessages.json

@@ -31,6 +31,10 @@
   "'{0}' is not a valid operator.": 224,
   "Expression cannot be represented by a type.": 225,
 
+  "Type '{0}' is cyclic. Module will include deferred garbage collection.": 900,
+  "Importing the table disables some indirect call optimizations.": 901,
+  "Exporting the table disables some indirect call optimizations.": 902,
+
   "Unterminated string literal.": 1002,
   "Identifier expected.": 1003,
   "'{0}' expected.": 1005,

src/diagnostics.ts

@@ -103,33 +103,6 @@ export class DiagnosticMessage {
     return new DiagnosticMessage(code, category, message);
   }
 
-  /** Creates a new informatory diagnostic message. */
-  static createInfo(
-    code: DiagnosticCode,
-    arg0: string | null = null,
-    arg1: string | null = null
-  ): DiagnosticMessage {
-    return DiagnosticMessage.create(code, DiagnosticCategory.INFO, arg0, arg1);
-  }
-
-  /** Creates a new warning diagnostic message. */
-  static createWarning(
-    code: DiagnosticCode,
-    arg0: string | null = null,
-    arg1: string | null = null
-  ): DiagnosticMessage {
-    return DiagnosticMessage.create(code, DiagnosticCategory.WARNING, arg0, arg1);
-  }
-
-  /** Creates a new error diagnostic message. */
-  static createError(
-    code: DiagnosticCode,
-    arg0: string | null = null,
-    arg1: string | null = null
-  ): DiagnosticMessage {
-    return DiagnosticMessage.create(code, DiagnosticCategory.ERROR, arg0, arg1);
-  }
-
   /** Adds a source range to this message. */
   withRange(range: Range): this {
     this.range = range;
@@ -273,7 +246,7 @@ export abstract class DiagnosticEmitter {
   emitDiagnostic(
     code: DiagnosticCode,
     category: DiagnosticCategory,
-    range: Range,
+    range: Range | null,
     relatedRange: Range | null,
     arg0: string | null = null,
     arg1: string | null = null,
@@ -282,17 +255,20 @@ export abstract class DiagnosticEmitter {
     // It is possible that the same diagnostic is emitted twice, for example
     // when compiling generics with different types or when recompiling a loop
     // because our initial assumptions didn't hold. Deduplicate these.
-    var seen = this.seen;
-    if (seen.has(range)) {
-      let codes = seen.get(range)!;
-      if (codes.has(code)) return;
-      codes.add(code);
-    } else {
-      let codes = new Set<DiagnosticCode>();
-      codes.add(code);
-      seen.set(range, codes);
+    if (range) {
+      let seen = this.seen;
+      if (seen.has(range)) {
+        let codes = seen.get(range)!;
+        if (codes.has(code)) return;
+        codes.add(code);
+      } else {
+        let codes = new Set<DiagnosticCode>();
+        codes.add(code);
+        seen.set(range, codes);
+      }
     }
-    var message = DiagnosticMessage.create(code, category, arg0, arg1, arg2).withRange(range);
+    var message = DiagnosticMessage.create(code, category, arg0, arg1, arg2);
+    if (range) message = message.withRange(range);
     if (relatedRange) message.relatedRange = relatedRange;
     this.diagnostics.push(message);
     // console.log(formatDiagnosticMessage(message, true, true) + "\n"); // temporary
@@ -302,7 +278,7 @@ export abstract class DiagnosticEmitter {
   /** Emits an informatory diagnostic message. */
   info(
     code: DiagnosticCode,
-    range: Range,
+    range: Range | null,
     arg0: string | null = null,
     arg1: string | null = null,
     arg2: string | null = null
@@ -325,7 +301,7 @@ export abstract class DiagnosticEmitter {
   /** Emits a warning diagnostic message. */
   warning(
     code: DiagnosticCode,
-    range: Range,
+    range: Range | null,
     arg0: string | null = null,
     arg1: string | null = null,
     arg2: string | null = null
@@ -348,7 +324,7 @@ export abstract class DiagnosticEmitter {
   /** Emits an error diagnostic message. */
   error(
     code: DiagnosticCode,
-    range: Range,
+    range: Range | null,
     arg0: string | null = null,
     arg1: string | null = null,
     arg2: string | null = null

src/index.ts

@@ -109,6 +109,11 @@ export function setOptimizeLevelHints(options: Options, optimizeLevel: i32, shri
   options.shrinkLevelHint = shrinkLevel;
 }
 
+/** Sets the `pedantic` option. */
+export function setPedantic(options: Options, pedantic: bool): void {
+  options.pedantic = pedantic;
+}
+
 // Program
 
 /** Creates a new Program. */

src/program.ts

@@ -1068,7 +1068,7 @@ export class Program extends DiagnosticEmitter {
   }
 
   /** Registers a constant integer value within the global scope. */
-  private registerConstantInteger(name: string, type: Type, value: I64): void {
+  registerConstantInteger(name: string, type: Type, value: I64): void {
     assert(type.is(TypeFlags.INTEGER)); // must be an integer type
     var global = new Global(
       name,
@@ -1797,6 +1797,9 @@ export class Program extends DiagnosticEmitter {
       validDecorators |= DecoratorFlags.EXTERNAL;
     } else {
       validDecorators |= DecoratorFlags.INLINE;
+      if (declaration.range.source.isLibrary) {
+        validDecorators |= DecoratorFlags.LAZY;
+      }
     }
     if (!declaration.is(CommonFlags.INSTANCE)) {
       if (parent.kind != ElementKind.CLASS_PROTOTYPE) {
@@ -1982,6 +1985,16 @@ export class Program extends DiagnosticEmitter {
   //   } while (current = current.base);
   //   return null;
   // }
+
+  /** Finds all cyclic classes. */
+  findCyclicClasses(): Set<Class> {
+    var managedClasses = this.managedClasses;
+    var cyclics = new Set<Class>();
+    for (let instance of managedClasses.values()) {
+      if (!instance.isAcyclic) cyclics.add(instance);
+    }
+    return cyclics;
+  }
 }
 
 /** Indicates the specific kind of an {@link Element}. */
@@ -3220,8 +3233,13 @@ export class ClassPrototype extends DeclaredElement {
   /** Tests if this prototype extends the specified. */
   extends(basePtototype: ClassPrototype | null): bool {
     var current: ClassPrototype | null = this;
-    do if (current === basePtototype) return true;
-    while (current = current.basePrototype);
+    var seen = new Set<ClassPrototype>();
+    do {
+      // cannot directly or indirectly extend itself
+      if (seen.has(current)) break;
+      seen.add(current);
+      if (current === basePtototype) return true;
+    } while (current = current.basePrototype);
     return false;
   }
 

std/assembly/rt/index.d.ts

@@ -11,4 +11,5 @@ declare function __visit(ref: usize, cookie: i32): void;
 declare function __visit_globals(cookie: u32): void;
 declare function __visit_members(ref: usize, cookie: u32): void;
 declare function __allocArray(length: i32, alignLog2: usize, id: u32, data?: usize): usize;
-declare const ASC_RTRACE: boolean;
+declare const ASC_RTRACE: bool;
+declare const __GC_ALL_ACYCLIC: bool;