Merge pull request microsoft#2138 from Microsoft/functionEmit

Remove optimization of eliding the preamble code for functions without statements.

Author: CyrusNajmabadi

src/compiler/emitter.ts

@@ -3088,6 +3088,8 @@ module ts {
 
                     write(tokenToString(node.operatorToken.kind));
 
+                    // Check if the right expression is on a different line versus the operator itself.  If so,
+                    // we'll emit newline.
                     if (!nodeEndIsOnSameLineAsNodeStart(node.operatorToken, node.right)) {
                         increaseIndent();
                         writeLine();
@@ -3940,58 +3942,21 @@ module ts {
             }
 
             function emitBlockFunctionBody(node: FunctionLikeDeclaration, body: Block) {
-                // If the body has no statements, and we know there's no code that would cause any 
-                // prologue to be emitted, then just do a simple emit if the empty block.
-                if (body.statements.length === 0 && !anyParameterHasBindingPatternOrInitializer(node)) {
-                    emitFunctionBodyWithNoStatements(node, body);
-                }
-                else {
-                    emitFunctionBodyWithStatements(node, body);
-                }
-            }
-
-            function anyParameterHasBindingPatternOrInitializer(func: FunctionLikeDeclaration) {
-                return forEach(func.parameters, hasBindingPatternOrInitializer);
-            }
-
-            function hasBindingPatternOrInitializer(parameter: ParameterDeclaration) {
-                return parameter.initializer || isBindingPattern(parameter.name);
-            }
-
-            function emitFunctionBodyWithNoStatements(node: FunctionLikeDeclaration, body: Block) {
-                var singleLine = isSingleLineEmptyBlock(node.body);
-
-                write(" {");
-                if (singleLine) {
-                    write(" ");
-                }
-                else {
-                    increaseIndent();
-                    writeLine();
-                }
-
-                emitLeadingCommentsOfPosition(body.statements.end);
-
-                if (!singleLine) {
-                    decreaseIndent();
-                }
-
-                emitToken(SyntaxKind.CloseBraceToken, body.statements.end);
-            }
-
-            function emitFunctionBodyWithStatements(node: FunctionLikeDeclaration, body: Block) {
                 write(" {");
                 scopeEmitStart(node);
 
-                var outPos = writer.getTextPos();
+                var initialTextPos = writer.getTextPos();
 
                 increaseIndent();
                 emitDetachedComments(body.statements);
+
+                // Emit all the directive prologues (like "use strict").  These have to come before
+                // any other preamble code we write (like parameter initializers).
                 var startIndex = emitDirectivePrologues(body.statements, /*startWithNewLine*/ true);
                 emitFunctionBodyPreamble(node);
                 decreaseIndent();
 
-                var preambleEmitted = writer.getTextPos() !== outPos;
+                var preambleEmitted = writer.getTextPos() !== initialTextPos;
 
                 if (!preambleEmitted && nodeEndIsOnSameLineAsNodeStart(body, body)) {
                     for (var i = 0, n = body.statements.length; i < n; i++) {

tests/baselines/reference/accessorWithRestParam.js

@@ -10,12 +10,22 @@ var C = (function () {
     function C() {
     }
     Object.defineProperty(C.prototype, "X", {
-        set: function () { },
+        set: function () {
+            var v = [];
+            for (var _i = 0; _i < arguments.length; _i++) {
+                v[_i - 0] = arguments[_i];
+            }
+        },
         enumerable: true,
         configurable: true
     });
     Object.defineProperty(C, "X", {
-        set: function () { },
+        set: function () {
+            var v2 = [];
+            for (var _i = 0; _i < arguments.length; _i++) {
+                v2[_i - 0] = arguments[_i];
+            }
+        },
         enumerable: true,
         configurable: true
     });

tests/baselines/reference/arrayLiteralInNonVarArgParameter.js

@@ -5,5 +5,10 @@ panic([], 'one', 'two');
 
 
 //// [arrayLiteralInNonVarArgParameter.js]
-function panic(val) { }
+function panic(val) {
+    var opt = [];
+    for (var _i = 1; _i < arguments.length; _i++) {
+        opt[_i - 1] = arguments[_i];
+    }
+}
 panic([], 'one', 'two');

tests/baselines/reference/baseTypeAfterDerivedType.js

@@ -20,6 +20,11 @@ interface Base2 {
 var Derived2 = (function () {
     function Derived2() {
     }
-    Derived2.prototype.method = function () { };
+    Derived2.prototype.method = function () {
+        var args = [];
+        for (var _i = 0; _i < arguments.length; _i++) {
+            args[_i - 0] = arguments[_i];
+        }
+    };
     return Derived2;
 })();

tests/baselines/reference/callWithSpread.js

@@ -61,6 +61,10 @@ var __extends = this.__extends || function (d, b) {
     d.prototype = new __();
 };
 function foo(x, y) {
+    var z = [];
+    for (var _i = 2; _i < arguments.length; _i++) {
+        z[_i - 2] = arguments[_i];
+    }
 }
 var a;
 var z;
@@ -89,6 +93,10 @@ var C = (function () {
         this.foo.apply(this, [x, y].concat(z));
     }
     C.prototype.foo = function (x, y) {
+        var z = [];
+        for (var _i = 2; _i < arguments.length; _i++) {
+            z[_i - 2] = arguments[_i];
+        }
     };
     return C;
 })();

tests/baselines/reference/collisionRestParameterFunction.js

@@ -56,6 +56,10 @@ function f3NoError() {
     var _i = 10; // no error
 }
 function f4(_i) {
+    var rest = [];
+    for (var _a = 1; _a < arguments.length; _a++) {
+        rest[_a - 1] = arguments[_a];
+    }
 }
 function f4NoError(_i) {
 }

tests/baselines/reference/collisionRestParameterFunctionExpressions.js

@@ -47,6 +47,10 @@ function foo() {
         var _i = 10; // no error
     }
     function f4(_i) {
+        var rest = [];
+        for (var _a = 1; _a < arguments.length; _a++) {
+            rest[_a - 1] = arguments[_a];
+        }
     }
     function f4NoError(_i) {
     }

tests/baselines/reference/contextualTyping.js.map

@@ -2210,8 +2210,8 @@ sourceFile:contextualTyping.ts
 2 >Emitted(87, 14) Source(146, 14) + SourceIndex(0)
 3 >Emitted(87, 15) Source(146, 15) + SourceIndex(0)
 4 >Emitted(87, 16) Source(146, 37) + SourceIndex(0)
-5 >Emitted(87, 20) Source(146, 40) + SourceIndex(0)
-6 >Emitted(87, 21) Source(146, 41) + SourceIndex(0)
+5 >Emitted(87, 20) Source(146, 40) + SourceIndex(0) name (c9t5)
+6 >Emitted(87, 21) Source(146, 41) + SourceIndex(0) name (c9t5)
 ---
 >>>;
 1 >

tests/baselines/reference/contextualTyping.sourcemap.txt

@@ -11,7 +11,12 @@ var f6 = () => { return [<any>10]; }
 
 
 //// [declFileRestParametersOfFunctionAndFunctionType.js]
-function f1() { }
+function f1() {
+    var args = [];
+    for (var _i = 0; _i < arguments.length; _i++) {
+        args[_i - 0] = arguments[_i];
+    }
+}
 function f2(x) { }
 function f3(x) { }
 function f4() { }