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ima02/resources/defects4j-checkout-closure-1f/test/com/google/javascript/jscomp/PeepholeRemoveDeadCodeTest.java

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2023-04-25 11:33:41 +00:00
/*
* Copyright 2004 The Closure Compiler Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.javascript.jscomp;
import com.google.javascript.rhino.Node;
/**
* Tests for PeepholeRemoveDeadCodeTest in isolation. Tests for the interaction
* of multiple peephole passes are in PeepholeIntegrationTest.
*/
public class PeepholeRemoveDeadCodeTest extends CompilerTestCase {
private static final String MATH =
"/** @const */ var Math = {};" +
"/** @nosideeffects */ Math.random = function(){};" +
"/** @nosideeffects */ Math.sin = function(){};";
public PeepholeRemoveDeadCodeTest() {
super(MATH);
}
@Override
public void setUp() throws Exception {
super.setUp();
enableLineNumberCheck(true);
}
@Override
public CompilerPass getProcessor(final Compiler compiler) {
return new CompilerPass() {
@Override
public void process(Node externs, Node root) {
SimpleDefinitionFinder definitionFinder =
new SimpleDefinitionFinder(compiler);
definitionFinder.process(externs, root);
new PureFunctionIdentifier(compiler, definitionFinder)
.process(externs, root);
PeepholeOptimizationsPass peepholePass =
new PeepholeOptimizationsPass(
compiler, new PeepholeRemoveDeadCode());
peepholePass.process(externs, root);
}
};
}
@Override
protected int getNumRepetitions() {
// Reduce this to 2 if we get better expression evaluators.
return 2;
}
private void foldSame(String js) {
testSame(js);
}
private void fold(String js, String expected) {
test(js, expected);
}
public void testFoldBlock() {
fold("{{foo()}}", "foo()");
fold("{foo();{}}", "foo()");
fold("{{foo()}{}}", "foo()");
fold("{{foo()}{bar()}}", "foo();bar()");
fold("{if(false)foo(); {bar()}}", "bar()");
fold("{if(false)if(false)if(false)foo(); {bar()}}", "bar()");
fold("{'hi'}", "");
fold("{x==3}", "");
fold("{ (function(){x++}) }", "");
fold("function f(){return;}", "function f(){return;}");
fold("function f(){return 3;}", "function f(){return 3}");
fold("function f(){if(x)return; x=3; return; }",
"function f(){if(x)return; x=3; return; }");
fold("{x=3;;;y=2;;;}", "x=3;y=2");
// Cases to test for empty block.
fold("while(x()){x}", "while(x());");
fold("while(x()){x()}", "while(x())x()");
fold("for(x=0;x<100;x++){x}", "for(x=0;x<100;x++);");
fold("for(x in y){x}", "for(x in y);");
}
/** Try to remove spurious blocks with multiple children */
public void testFoldBlocksWithManyChildren() {
fold("function f() { if (false) {} }", "function f(){}");
fold("function f() { { if (false) {} if (true) {} {} } }",
"function f(){}");
fold("{var x; var y; var z; function f() { { var a; { var b; } } } }",
"var x;var y;var z;function f(){var a;var b}");
}
public void testIf() {
fold("if (1){ x=1; } else { x = 2;}", "x=1");
fold("if (false){ x = 1; } else { x = 2; }", "x=2");
fold("if (undefined){ x = 1; } else { x = 2; }", "x=2");
fold("if (null){ x = 1; } else { x = 2; }", "x=2");
fold("if (void 0){ x = 1; } else { x = 2; }", "x=2");
fold("if (void foo()){ x = 1; } else { x = 2; }",
"foo();x=2");
fold("if (false){ x = 1; } else if (true) { x = 3; } else { x = 2; }",
"x=3");
fold("if (x){ x = 1; } else if (false) { x = 3; }",
"if(x)x=1");
}
public void testHook() {
fold("true ? a() : b()", "a()");
fold("false ? a() : b()", "b()");
fold("a() ? b() : true", "a() && b()");
fold("a() ? true : b()", "a() || b()");
fold("(a = true) ? b() : c()", "a = true, b()");
fold("(a = false) ? b() : c()", "a = false, c()");
fold("do {f()} while((a = true) ? b() : c())",
"do {f()} while((a = true) , b())");
fold("do {f()} while((a = false) ? b() : c())",
"do {f()} while((a = false) , c())");
fold("var x = (true) ? 1 : 0", "var x=1");
fold("var y = (true) ? ((false) ? 12 : (cond ? 1 : 2)) : 13",
"var y=cond?1:2");
foldSame("var z=x?void 0:y()");
foldSame("z=x?void 0:y()");
foldSame("z*=x?void 0:y()");
foldSame("var z=x?y():void 0");
foldSame("(w?x:void 0).y=z");
foldSame("(w?x:void 0).y+=z");
fold("y = (x ? void 0 : void 0)", "y = void 0");
fold("y = (x ? f() : f())", "y = f()");
}
public void testConstantConditionWithSideEffect1() {
fold("if (b=true) x=1;", "b=true;x=1");
fold("if (b=/ab/) x=1;", "b=/ab/;x=1");
fold("if (b=/ab/){ x=1; } else { x=2; }", "b=/ab/;x=1");
fold("var b;b=/ab/;if(b)x=1;", "var b;b=/ab/;x=1");
foldSame("var b;b=f();if(b)x=1;");
fold("var b=/ab/;if(b)x=1;", "var b=/ab/;x=1");
foldSame("var b=f();if(b)x=1;");
foldSame("b=b++;if(b)x=b;");
fold("(b=0,b=1);if(b)x=b;", "b=0,b=1;if(b)x=b;");
fold("b=1;if(foo,b)x=b;","b=1;x=b;");
foldSame("b=1;if(foo=1,b)x=b;");
}
public void testConstantConditionWithSideEffect2() {
fold("(b=true)?x=1:x=2;", "b=true,x=1");
fold("(b=false)?x=1:x=2;", "b=false,x=2");
fold("if (b=/ab/) x=1;", "b=/ab/;x=1");
fold("var b;b=/ab/;(b)?x=1:x=2;", "var b;b=/ab/;x=1");
foldSame("var b;b=f();(b)?x=1:x=2;");
fold("var b=/ab/;(b)?x=1:x=2;", "var b=/ab/;x=1");
foldSame("var b=f();(b)?x=1:x=2;");
}
public void testVarLifting() {
fold("if(true)var a", "var a");
fold("if(false)var a", "var a");
// More var lifting tests in PeepholeIntegrationTests
}
public void testFoldUselessWhile() {
fold("while(false) { foo() }", "");
fold("while(void 0) { foo() }", "");
fold("while(undefined) { foo() }", "");
foldSame("while(true) foo()");
fold("while(false) { var a = 0; }", "var a");
// Make sure it plays nice with minimizing
fold("while(false) { foo(); continue }", "");
fold("while(0) { foo() }", "");
}
public void testFoldUselessFor() {
fold("for(;false;) { foo() }", "");
fold("for(;void 0;) { foo() }", "");
fold("for(;undefined;) { foo() }", "");
fold("for(;true;) foo() ", "for(;;) foo() ");
foldSame("for(;;) foo()");
fold("for(;false;) { var a = 0; }", "var a");
// Make sure it plays nice with minimizing
fold("for(;false;) { foo(); continue }", "");
}
public void testFoldUselessDo() {
fold("do { foo() } while(false);", "foo()");
fold("do { foo() } while(void 0);", "foo()");
fold("do { foo() } while(undefined);", "foo()");
fold("do { foo() } while(true);", "do { foo() } while(true);");
fold("do { var a = 0; } while(false);", "var a=0");
fold("do { var a = 0; } while(!{a:foo()});", "var a=0;foo()");
// Can't fold with break or continues.
foldSame("do { foo(); continue; } while(0)");
foldSame("do { foo(); break; } while(0)");
}
public void testMinimizeWhileConstantCondition() {
fold("while(true) foo()", "while(true) foo()");
fold("while(0) foo()", "");
fold("while(0.0) foo()", "");
fold("while(NaN) foo()", "");
fold("while(null) foo()", "");
fold("while(undefined) foo()", "");
fold("while('') foo()", "");
}
public void testFoldConstantCommaExpressions() {
fold("if (true, false) {foo()}", "");
fold("if (false, true) {foo()}", "foo()");
fold("true, foo()", "foo()");
fold("(1 + 2 + ''), foo()", "foo()");
}
public void testRemoveUselessOps() {
// There are four place where expression results are discarded:
// - a top-level expression EXPR_RESULT
// - the LHS of a COMMA
// - the FOR init expression
// - the FOR increment expression
// Known side-effect free functions calls are removed.
fold("Math.random()", "");
fold("Math.random(f() + g())", "f(),g();");
fold("Math.random(f(),g(),h())", "f(),g(),h();");
// Calls to functions with unknown side-effects are are left.
foldSame("f();");
foldSame("(function () { f(); })();");
// We know that this function has no side effects because of the
// PureFunctionIdentifier.
fold("(function () {})();", "");
// Uncalled function expressions are removed
fold("(function () {});", "");
fold("(function f() {});", "");
// ... including any code they contain.
fold("(function () {foo();});", "");
// Useless operators are removed.
fold("+f()", "f()");
fold("a=(+f(),g())", "a=(f(),g())");
fold("a=(true,g())", "a=g()");
fold("f(),true", "f()");
fold("f() + g()", "f(),g()");
fold("for(;;+f()){}", "for(;;f()){}");
fold("for(+f();;g()){}", "for(f();;g()){}");
fold("for(;;Math.random(f(),g(),h())){}", "for(;;f(),g(),h()){}");
// The optimization cascades into conditional expressions:
fold("g() && +f()", "g() && f()");
fold("g() || +f()", "g() || f()");
fold("x ? g() : +f()", "x ? g() : f()");
fold("+x()", "x()");
fold("+x() * 2", "x()");
fold("-(+x() * 2)", "x()");
fold("2 -(+x() * 2)", "x()");
fold("x().foo", "x()");
foldSame("x().foo()");
foldSame("x++");
foldSame("++x");
foldSame("x--");
foldSame("--x");
foldSame("x = 2");
foldSame("x *= 2");
// Sanity check, other expression are left alone.
foldSame("function f() {}");
foldSame("var x;");
}
public void testOptimizeSwitch() {
fold("switch(a){}", "");
fold("switch(foo()){}", "foo()");
fold("switch(a){default:}", "");
fold("switch(a){default:break;}", "");
fold("switch(a){default:var b;break;}", "var b");
fold("switch(a){case 1: default:}", "");
fold("switch(a){default: case 1:}", "");
fold("switch(a){default: break; case 1:break;}", "");
fold("switch(a){default: var b; break; case 1: var c; break;}",
"var c; var b;");
// Can't remove cases if a default exists.
foldSame("function f() {switch(a){default: return; case 1: break;}}");
foldSame("function f() {switch(a){case 1: foo();}}");
foldSame("function f() {switch(a){case 3: case 2: case 1: foo();}}");
fold("function f() {switch(a){case 2: case 1: default: foo();}}",
"function f() {switch(a){default: foo();}}");
fold("switch(a){case 1: default:break; case 2: foo()}",
"switch(a){case 2: foo()}");
foldSame("switch(a){case 1: goo(); default:break; case 2: foo()}");
// TODO(johnlenz): merge the useless "case 2"
foldSame("switch(a){case 1: goo(); case 2:break; case 3: foo()}");
// Can't remove unused code with a "var" in it.
fold("switch(1){case 2: var x=0;}", "var x;");
fold("switch ('repeated') {\n" +
"case 'repeated':\n" +
" foo();\n" +
" break;\n" +
"case 'repeated':\n" +
" var x=0;\n" +
" break;\n" +
"}",
"var x; {foo();}");
// Can't remove cases if something useful is done.
foldSame("switch(a){case 1: var c =2; break;}");
foldSame("function f() {switch(a){case 1: return;}}");
foldSame("x:switch(a){case 1: break x;}");
fold("switch ('foo') {\n" +
"case 'foo':\n" +
" foo();\n" +
" break;\n" +
"case 'bar':\n" +
" bar();\n" +
" break;\n" +
"}",
"{foo();}");
fold("switch ('noMatch') {\n" +
"case 'foo':\n" +
" foo();\n" +
" break;\n" +
"case 'bar':\n" +
" bar();\n" +
" break;\n" +
"}",
"");
foldSame("switch ('fallThru') {\n" +
"case 'fallThru':\n" +
" if (foo(123) > 0) {\n" +
" foobar(1);\n" +
" break;\n" +
" }\n" +
" foobar(2);\n" +
"case 'bar':\n" +
" bar();\n" +
"}");
foldSame("switch ('fallThru') {\n" +
"case 'fallThru':\n" +
" foo();\n" +
"case 'bar':\n" +
" bar();\n" +
"}");
foldSame("switch ('hasDefaultCase') {\n" +
"case 'foo':\n" +
" foo();\n" +
" break;\n" +
"default:\n" +
" bar();\n" +
" break;\n" +
"}");
fold("switch ('repeated') {\n" +
"case 'repeated':\n" +
" foo();\n" +
" break;\n" +
"case 'repeated':\n" +
" bar();\n" +
" break;\n" +
"}",
"{foo();}");
fold("switch ('foo') {\n" +
"case 'bar':\n" +
" bar();\n" +
" break;\n" +
"case notConstant:\n" +
" foobar();\n" +
" break;\n" +
"case 'foo':\n" +
" foo();\n" +
" break;\n" +
"}",
"switch ('foo') {\n" +
"case notConstant:\n" +
" foobar();\n" +
" break;\n" +
"case 'foo':\n" +
" foo();\n" +
" break;\n" +
"}");
fold("switch (1) {\n" +
"case 1:\n" +
" foo();\n" +
" break;\n" +
"case 2:\n" +
" bar();\n" +
" break;\n" +
"}",
"{foo();}");
fold("switch (1) {\n" +
"case 1.1:\n" +
" foo();\n" +
" break;\n" +
"case 2:\n" +
" bar();\n" +
" break;\n" +
"}",
"");
foldSame("switch (0) {\n" +
"case NaN:\n" +
" foobar();\n" +
" break;\n" +
"case -0.0:\n" +
" foo();\n" +
" break;\n" +
"case 2:\n" +
" bar();\n" +
" break;\n" +
"}");
foldSame("switch ('\\v') {\n" +
"case '\\u000B':\n" +
" foo();\n" +
"}");
foldSame("switch ('empty') {\n" +
"case 'empty':\n" +
"case 'foo':\n" +
" foo();\n" +
"}");
}
public void testRemoveNumber() {
test("3", "");
}
public void testRemoveVarGet1() {
test("a", "");
}
public void testRemoveVarGet2() {
test("var a = 1;a", "var a = 1");
}
public void testRemoveNamespaceGet1() {
test("var a = {};a.b", "var a = {}");
}
public void testRemoveNamespaceGet2() {
test("var a = {};a.b=1;a.b", "var a = {};a.b=1");
}
public void testRemovePrototypeGet1() {
test("var a = {};a.prototype.b", "var a = {}");
}
public void testRemovePrototypeGet2() {
test("var a = {};a.prototype.b = 1;a.prototype.b",
"var a = {};a.prototype.b = 1");
}
public void testRemoveAdd1() {
test("1 + 2", "");
}
public void testNoRemoveVar1() {
testSame("var a = 1");
}
public void testNoRemoveVar2() {
testSame("var a = 1, b = 2");
}
public void testNoRemoveAssign1() {
testSame("a = 1");
}
public void testNoRemoveAssign2() {
testSame("a = b = 1");
}
public void testNoRemoveAssign3() {
test("1 + (a = 2)", "a = 2");
}
public void testNoRemoveAssign4() {
testSame("x.a = 1");
}
public void testNoRemoveAssign5() {
testSame("x.a = x.b = 1");
}
public void testNoRemoveAssign6() {
test("1 + (x.a = 2)", "x.a = 2");
}
public void testNoRemoveCall1() {
testSame("a()");
}
public void testNoRemoveCall2() {
test("a()+b()", "a(),b()");
}
public void testNoRemoveCall3() {
testSame("a() && b()");
}
public void testNoRemoveCall4() {
testSame("a() || b()");
}
public void testNoRemoveCall5() {
test("a() || 1", "a()");
}
public void testNoRemoveCall6() {
testSame("1 || a()");
}
public void testNoRemoveThrow1() {
testSame("function f(){throw a()}");
}
public void testNoRemoveThrow2() {
testSame("function f(){throw a}");
}
public void testNoRemoveThrow3() {
testSame("function f(){throw 10}");
}
public void testRemoveInControlStructure1() {
test("if(x()) 1", "x()");
}
public void testRemoveInControlStructure2() {
test("while(2) 1", "while(2);");
}
public void testRemoveInControlStructure3() {
test("for(1;2;3) 4", "for(;;);");
}
public void testHook1() {
test("1 ? 2 : 3", "");
}
public void testHook2() {
test("x ? a() : 3", "x && a()");
}
public void testHook3() {
test("x ? 2 : a()", "x || a()");
}
public void testHook4() {
testSame("x ? a() : b()");
}
public void testHook5() {
test("a() ? 1 : 2", "a()");
}
public void testHook6() {
test("a() ? b() : 2", "a() && b()");
}
// TODO(johnlenz): Consider adding a post optimization pass to
// convert OR into HOOK to save parentheses when the operator
// precedents would require them.
public void testHook7() {
test("a() ? 1 : b()", "a() || b()");
}
public void testHook8() {
testSame("a() ? b() : c()");
}
public void testShortCircuit1() {
testSame("1 && a()");
}
public void testShortCircuit2() {
test("1 && a() && 2", "1 && a()");
}
public void testShortCircuit3() {
test("a() && 1 && 2", "a()");
}
public void testShortCircuit4() {
testSame("a() && 1 && b()");
}
public void testComplex1() {
test("1 && a() + b() + c()", "1 && (a(), b(), c())");
}
public void testComplex2() {
test("1 && (a() ? b() : 1)", "1 && a() && b()");
}
public void testComplex3() {
test("1 && (a() ? b() : 1 + c())", "1 && (a() ? b() : c())");
}
public void testComplex4() {
test("1 && (a() ? 1 : 1 + c())", "1 && (a() || c())");
}
public void testComplex5() {
// can't simplify LHS of short circuit statements with side effects
testSame("(a() ? 1 : 1 + c()) && foo()");
}
public void testNoRemoveFunctionDeclaration1() {
testSame("function foo(){}");
}
public void testNoRemoveFunctionDeclaration2() {
testSame("var foo = function (){}");
}
public void testNoSimplifyFunctionArgs1() {
testSame("f(1 + 2, 3 + g())");
}
public void testNoSimplifyFunctionArgs2() {
testSame("1 && f(1 + 2, 3 + g())");
}
public void testNoSimplifyFunctionArgs3() {
testSame("1 && foo(a() ? b() : 1 + c())");
}
public void testNoRemoveInherits1() {
testSame("var a = {}; this.b = {}; var goog = {}; goog.inherits(b, a)");
}
public void testNoRemoveInherits2() {
test("var a = {}; this.b = {}; var goog = {}; goog.inherits(b, a) + 1",
"var a = {}; this.b = {}; var goog = {}; goog.inherits(b, a)");
}
public void testNoRemoveInherits3() {
testSame("this.a = {}; var b = {}; b.inherits(a);");
}
public void testNoRemoveInherits4() {
test("this.a = {}; var b = {}; b.inherits(a) + 1;",
"this.a = {}; var b = {}; b.inherits(a)");
}
public void testRemoveFromLabel1() {
test("LBL: void 0", "LBL: {}");
}
public void testRemoveFromLabel2() {
test("LBL: foo() + 1 + bar()", "LBL: foo(),bar()");
}
public void testCall1() {
test("Math.sin(0);", "");
}
public void testCall2() {
test("1 + Math.sin(0);", "");
}
public void testNew1() {
test("new Date;", "");
}
public void testNew2() {
test("1 + new Date;", "");
}
public void testFoldAssign() {
test("x=x", "");
testSame("x=xy");
testSame("x=x + 1");
testSame("x.a=x.a");
test("var y=(x=x)", "var y=x");
test("y=1 + (x=x)", "y=1 + x");
}
public void testTryCatchFinally() {
testSame("try {foo()} catch (e) {bar()}");
testSame("try { try {foo()} catch (e) {bar()}} catch (x) {bar()}");
test("try {var x = 1} finally {}", "var x = 1;");
testSame("try {var x = 1} finally {x()}");
test("function f() { return; try{var x = 1}finally{} }",
"function f() { return; var x = 1; }");
test("try {} finally {x()}", "x()");
test("try {} catch (e) { bar()} finally {x()}", "x()");
test("try {} catch (e) { bar()}", "");
test("try {} catch (e) { var a = 0; } finally {x()}", "var a; x()");
test("try {} catch (e) {}", "");
test("try {} finally {}", "");
test("try {} catch (e) {} finally {}", "");
}
public void testObjectLiteral() {
test("({})", "");
test("({a:1})", "");
test("({a:foo()})", "foo()");
test("({'a':foo()})", "foo()");
}
public void testArrayLiteral() {
test("([])", "");
test("([1])", "");
test("([a])", "");
test("([foo()])", "foo()");
}
}