/*
* Copyright 2009 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.jscomp.CompilerOptions.Reach;
/**
* A CompilationLevel represents the level of optimization that should be
* applied when compiling JavaScript code.
*
* @author bolinfest@google.com (Michael Bolin)
*/
public enum CompilationLevel {
/**
* WHITESPACE_ONLY removes comments and extra whitespace in the input JS.
*/
WHITESPACE_ONLY,
/**
* SIMPLE_OPTIMIZATIONS performs transformations to the input JS that do not
* require any changes to JS that depend on the input JS. For example,
* function arguments are renamed (which should not matter to code that
* depends on the input JS), but functions themselves are not renamed (which
* would otherwise require external code to change to use the renamed function
* names).
*/
SIMPLE_OPTIMIZATIONS,
/**
* ADVANCED_OPTIMIZATIONS aggressively reduces code size by renaming function
* names and variables, removing code which is never called, etc.
*/
ADVANCED_OPTIMIZATIONS,
;
public static CompilationLevel fromString(String value) {
if (value == null) {
return null;
}
switch (value) {
case "WHITESPACE_ONLY":
case "WHITESPACE":
return CompilationLevel.WHITESPACE_ONLY;
case "SIMPLE_OPTIMIZATIONS":
case "SIMPLE":
return CompilationLevel.SIMPLE_OPTIMIZATIONS;
case "ADVANCED_OPTIMIZATIONS":
case "ADVANCED":
return CompilationLevel.ADVANCED_OPTIMIZATIONS;
}
return null;
}
private CompilationLevel() {}
public void setOptionsForCompilationLevel(CompilerOptions options) {
switch (this) {
case WHITESPACE_ONLY:
applyBasicCompilationOptions(options);
break;
case SIMPLE_OPTIMIZATIONS:
applySafeCompilationOptions(options);
break;
case ADVANCED_OPTIMIZATIONS:
applyFullCompilationOptions(options);
break;
default:
throw new RuntimeException("Unknown compilation level.");
}
}
public void setDebugOptionsForCompilationLevel(CompilerOptions options) {
options.setAnonymousFunctionNaming(AnonymousFunctionNamingPolicy.UNMAPPED);
options.generatePseudoNames = true;
options.removeClosureAsserts = false;
options.removeJ2clAsserts = false;
// Don't shadow variables as it is too confusing.
options.shadowVariables = false;
}
/**
* Gets options that only strip whitespace and comments.
* @param options The CompilerOptions object to set the options on.
*/
private static void applyBasicCompilationOptions(CompilerOptions options) {
options.skipAllCompilerPasses();
}
/**
* Add options that are safe. Safe means options that won't break the
* JavaScript code even if no symbols are exported and no coding convention
* is used.
* @param options The CompilerOptions object to set the options on.
*/
private static void applySafeCompilationOptions(CompilerOptions options) {
// ReplaceIdGenerators is on by default, but should run in simple mode.
options.replaceIdGenerators = false;
// Does not call applyBasicCompilationOptions(options) because the call to
// skipAllCompilerPasses() cannot be easily undone.
options.dependencyOptions.setDependencySorting(true);
options.setClosurePass(true);
options.setRenamingPolicy(VariableRenamingPolicy.LOCAL, PropertyRenamingPolicy.OFF);
options.shadowVariables = true;
options.setInlineVariables(Reach.LOCAL_ONLY);
options.setFlowSensitiveInlineVariables(true);
options.setInlineFunctions(Reach.LOCAL_ONLY);
options.setAssumeClosuresOnlyCaptureReferences(false);
options.setCheckGlobalThisLevel(CheckLevel.OFF);
options.setFoldConstants(true);
options.setCoalesceVariableNames(true);
options.setDeadAssignmentElimination(true);
options.setCollapseVariableDeclarations(true);
options.convertToDottedProperties = true;
options.labelRenaming = true;
options.setRemoveDeadCode(true);
options.setOptimizeArgumentsArray(true);
options.setRemoveUnusedVariables(Reach.LOCAL_ONLY);
options.collapseObjectLiterals = true;
options.setProtectHiddenSideEffects(true);
}
/**
* Add the options that will work only if the user exported all the symbols
* correctly.
* @param options The CompilerOptions object to set the options on.
*/
private static void applyFullCompilationOptions(CompilerOptions options) {
// Do not call applySafeCompilationOptions(options) because the call can
// create possible conflicts between multiple diagnostic groups.
options.setCheckSymbols(true);
options.setCheckTypes(true);
// All the safe optimizations.
options.dependencyOptions.setDependencySorting(true);
options.setClosurePass(true);
options.setFoldConstants(true);
options.setCoalesceVariableNames(true);
options.setDeadAssignmentElimination(true);
options.setExtractPrototypeMemberDeclarations(true);
options.setCollapseVariableDeclarations(true);
options.setConvertToDottedProperties(true);
options.setLabelRenaming(true);
options.setRemoveDeadCode(true);
options.setOptimizeArgumentsArray(true);
options.setCollapseObjectLiterals(true);
options.setProtectHiddenSideEffects(true);
// All the advanced optimizations.
options.setRemoveClosureAsserts(true);
options.setRemoveAbstractMethods(true);
options.setRemoveSuperMethods(true);
options.setReserveRawExports(true);
options.setRenamingPolicy(VariableRenamingPolicy.ALL, PropertyRenamingPolicy.ALL_UNQUOTED);
options.setShadowVariables(true);
options.setRemoveUnusedPrototypeProperties(true);
options.setRemoveUnusedPrototypePropertiesInExterns(false);
options.setRemoveUnusedClassProperties(true);
options.setCollapseAnonymousFunctions(true);
options.setCollapseProperties(true);
options.setCheckGlobalThisLevel(CheckLevel.WARNING);
options.setRewriteFunctionExpressions(false);
options.setSmartNameRemoval(true);
options.setExtraSmartNameRemoval(true);
options.setInlineConstantVars(true);
options.setInlineFunctions(Reach.ALL);
options.setAssumeClosuresOnlyCaptureReferences(false);
options.setInlineVariables(Reach.ALL);
options.setFlowSensitiveInlineVariables(true);
options.setComputeFunctionSideEffects(true);
// Remove unused vars also removes unused functions.
options.setRemoveUnusedVariables(Reach.ALL);
// Move code around based on the defined modules.
options.setCrossModuleCodeMotion(true);
options.setCrossModuleMethodMotion(true);
// Call optimizations
options.setDevirtualizePrototypeMethods(true);
options.setOptimizeParameters(true);
options.setOptimizeReturns(true);
options.setOptimizeCalls(true);
}
/**
* Enable additional optimizations that use type information. Only has
* an effect for ADVANCED_OPTIMIZATIONS; this is a no-op for other modes.
* @param options The CompilerOptions object to set the options on.
*/
public void setTypeBasedOptimizationOptions(CompilerOptions options) {
switch (this) {
case ADVANCED_OPTIMIZATIONS:
options.setDisambiguateProperties(true);
options.setAmbiguateProperties(true);
options.setInlineProperties(true);
options.setUseTypesForLocalOptimization(true);
break;
case SIMPLE_OPTIMIZATIONS:
case WHITESPACE_ONLY:
break;
}
}
/**
* Enable additional optimizations that operate on global declarations. Advanced mode does
* this by default, but this isn't valid in simple mode in the general case and should only
* be enabled when code is self contained (such as when it is enclosed by a function wrapper.
*
* @param options The CompilerOptions object to set the options on.
*/
public void setWrappedOutputOptimizations(CompilerOptions options) {
// Global variables and properties names can't conflict.
options.reserveRawExports = false;
switch (this) {
case SIMPLE_OPTIMIZATIONS:
// Enable global variable optimizations (but not property optimizations)
options.setVariableRenaming(VariableRenamingPolicy.ALL);
options.setCollapseAnonymousFunctions(true);
options.setInlineConstantVars(true);
options.setInlineFunctions(Reach.ALL);
options.setInlineVariables(Reach.ALL);
options.setRemoveUnusedVariables(Reach.ALL);
break;
case ADVANCED_OPTIMIZATIONS:
case WHITESPACE_ONLY:
break;
}
}
}