Attachment #158761 for bug #302446




				}
				break;
		}
		// set the optimize constant to optimize code gen
		if ((initsWhenTrue.tagBits & FlowInfo.UNREACHABLE) != 0) {
			this.optimizedBooleanConstant = BooleanConstant.fromValue(false);
		} else if ((initsWhenFalse.tagBits & FlowInfo.UNREACHABLE) != 0) {
			this.optimizedBooleanConstant = BooleanConstant.fromValue(true);
		}
		// we do not impact enclosing try context because this kind of protection
		// does not preclude the variable from being null in an enclosing scope
	}




	int elseInitStateIndex = -1;
	int mergedInitStateIndex = -1;

public IfStatement(Expression condition, Statement thenStatement, int sourceStart, int sourceEnd) {
	this.condition = condition;
	this.thenStatement = thenStatement;
	// remember useful empty statement

	if (isConditionOptimizedTrue) {
		elseFlowInfo.setReachMode(FlowInfo.UNREACHABLE);
	}
	if (((flowInfo.tagBits & FlowInfo.UNREACHABLE) == 0) && 
			((thenFlowInfo.tagBits & FlowInfo.UNREACHABLE) != 0)) {
		// Mark then block as unreachable
		// No need if the whole if-else construct itself lies in unreachable code
		this.bits |= ASTNode.IsThenStatementUnreachable;
	} else if (((flowInfo.tagBits & FlowInfo.UNREACHABLE) == 0) &&
			((elseFlowInfo.tagBits & FlowInfo.UNREACHABLE) != 0)) {
		// Mark else block as unreachable
		// No need if the whole if-else construct itself lies in unreachable code
		this.bits |= ASTNode.IsElseStatementUnreachable;
	}
	if (this.thenStatement != null) {
		// Save info for code gen
		this.thenInitStateIndex = currentScope.methodScope().recordInitializationStates(thenFlowInfo);
		if (isConditionOptimizedFalse || ((this.bits & ASTNode.IsThenStatementUnreachable) == ASTNode.IsThenStatementUnreachable)) {
			if (!isKnowDeadCodePattern(this.condition) || currentScope.compilerOptions().reportDeadCodeInTrivialIfStatement) {
				this.thenStatement.complainIfUnreachable(thenFlowInfo, currentScope, initialComplaintLevel);
			} else {
				// its a known coding pattern which should be tolerated by dead code analysis
				// according to isKnowDeadCodePattern()
				this.bits &= ~ASTNode.IsThenStatementUnreachable;
			}
		}
		thenFlowInfo = this.thenStatement.analyseCode(currentScope, flowContext, thenFlowInfo);


	// process the ELSE part
	if (this.elseStatement != null) {
		// signal else clause unnecessarily nested, tolerate else-if code pattern
		if (thenFlowInfo == FlowInfo.DEAD_END
				&& (this.bits & IsElseIfStatement) == 0 	// else of an else-if
				&& !(this.elseStatement instanceof IfStatement)) {
			currentScope.problemReporter().unnecessaryElse(this.elseStatement);
		}
		// Save info for code gen
		this.elseInitStateIndex = currentScope.methodScope().recordInitializationStates(elseFlowInfo);
		if (isConditionOptimizedTrue || ((this.bits & ASTNode.IsElseStatementUnreachable) != 0)) {
			if (!isKnowDeadCodePattern(this.condition) || currentScope.compilerOptions().reportDeadCodeInTrivialIfStatement) {
				this.elseStatement.complainIfUnreachable(elseFlowInfo, currentScope, initialComplaintLevel);
			} else {
				// its a known coding pattern which should be tolerated by dead code analysis
				// according to isKnowDeadCodePattern()
				this.bits &= ~ASTNode.IsElseStatementUnreachable;
			}
		}
		elseFlowInfo = this.elseStatement.analyseCode(currentScope, flowContext, elseFlowInfo);
	}
	// merge THEN & ELSE initializations
	FlowInfo mergedInfo = FlowInfo.mergedOptimizedBranchesIfElse(
		thenFlowInfo,
		isConditionOptimizedTrue,
		elseFlowInfo,
		isConditionOptimizedFalse,
		true /*if(true){ return; }  fake-reachable(); */,
		flowInfo);
	this.mergedInitStateIndex = currentScope.methodScope().recordInitializationStates(mergedInfo);
	return mergedInfo;
}

	if (hasThenPart) {
		BranchLabel falseLabel = null;
		// generate boolean condition only if needed
		if (((this.bits & ASTNode.IsElseStatementUnreachable) == ASTNode.IsElseStatementUnreachable) ||
				(cst != Constant.NotAConstant && cst.booleanValue() == true)) {
			// No need to generate if condition statement when we know that only the then action
			// will be executed
			this.condition.generateCode(currentScope, codeStream, false);

		}
	} else if (hasElsePart) {
		// generate boolean condition only if needed
		if ((this.bits & ASTNode.IsThenStatementUnreachable) == ASTNode.IsThenStatementUnreachable ||
				(cst != Constant.NotAConstant && cst.booleanValue() == false)) {
			// No need to generate if condition statement when we know that only the else action
			// will be executed
			this.condition.generateCode(currentScope, codeStream, false);




/*******************************************************************************
 * Copyright (c) 2000, 2010 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at

}

/**
 * Merge if-else branches using optimized boolean conditions
 */
public static UnconditionalFlowInfo mergedOptimizedBranchesIfElse(
		FlowInfo initsWhenTrue, boolean isOptimizedTrue,
		FlowInfo initsWhenFalse, boolean isOptimizedFalse,
		boolean allowFakeDeadBranch, FlowInfo flowInfo) {
	UnconditionalFlowInfo mergedInfo;
	if (isOptimizedTrue){
		if (initsWhenTrue == FlowInfo.DEAD_END && allowFakeDeadBranch) {
			mergedInfo = initsWhenFalse.setReachMode(FlowInfo.UNREACHABLE).
				unconditionalInits();
		}
		else {
			mergedInfo =
				initsWhenTrue.addPotentialInitializationsFrom(initsWhenFalse.
					nullInfoLessUnconditionalCopy()).
				unconditionalInits();
		}
	}
	else if (isOptimizedFalse) {
		if (initsWhenFalse == FlowInfo.DEAD_END && allowFakeDeadBranch) {
			mergedInfo = initsWhenTrue.setReachMode(FlowInfo.UNREACHABLE).
				unconditionalInits();
		}
		else {
			mergedInfo =
				initsWhenFalse.addPotentialInitializationsFrom(initsWhenTrue.
					nullInfoLessUnconditionalCopy()).
				unconditionalInits();
		}
	}
	else if ((flowInfo.tagBits & FlowInfo.UNREACHABLE) == 0 &&
				(initsWhenFalse.tagBits & FlowInfo.UNREACHABLE) != 0 &&
				initsWhenTrue != FlowInfo.DEAD_END &&
				initsWhenFalse != FlowInfo.DEAD_END) {
		// Done when the then branch will always be executed but the condition doesnt have a boolean
		// true or false (i.e if(true), etc) for sure
		// We don't do this if both if and else branches themselves are in an unreachable code
		// or if any of them is a DEAD_END (eg. contains 'return' or 'throws')
		mergedInfo =
			initsWhenTrue.addPotentialInitializationsFrom(initsWhenFalse.
				nullInfoLessUnconditionalCopy()).
			unconditionalInits();
		// if a variable is only initialized in one branch and not initialized in the other,
		// then we need to cast a doubt on its initialization in the merged info
		mergedInfo.definiteInits &= initsWhenFalse.unconditionalCopy().definiteInits;
		
	}
	else if ((flowInfo.tagBits & FlowInfo.UNREACHABLE) == 0 &&
			(initsWhenTrue.tagBits & FlowInfo.UNREACHABLE) != 0 && initsWhenTrue != FlowInfo.DEAD_END
			&& initsWhenFalse != FlowInfo.DEAD_END) {
		// Done when the else branch will always be executed but the condition doesnt have a boolean
		// true or false (i.e if(true), etc) for sure
		// We don't do this if both if and else branches themselves are in an unreachable code
		// or if any of them is a DEAD_END (eg. contains 'return' or 'throws')
		mergedInfo = 
			initsWhenFalse.addPotentialInitializationsFrom(initsWhenTrue.
				nullInfoLessUnconditionalCopy()).
			unconditionalInits();
		// if a variable is only initialized in one branch and not initialized in the other,
		// then we need to cast a doubt on its initialization in the merged info
		mergedInfo.definiteInits &= initsWhenTrue.unconditionalCopy().definiteInits;
	}
	else {
		mergedInfo = initsWhenTrue.
			mergedWith(initsWhenFalse.unconditionalInits());
	}
	return mergedInfo;
}

/**
 * Return REACHABLE if this flow info is reachable, UNREACHABLE
 * else.
 * @return REACHABLE if this flow info is reachable, UNREACHABLE




}

	// Static initializer to specify tests subset using TESTS_* static variables
// All specified tests which does not belong to the class are skipped...
// Only the highest compliance level is run; add the VM argument
// -Dcompliance=1.4 (for example) to lower it if needed
static {
//	TESTS_NAMES = new String[] { "test0572_if_statement" };
//    	TESTS_NUMBERS = new int[] { 561 };
//    	TESTS_NUMBERS = new int[] { 2999 };
//    	TESTS_RANGE = new int[] { 2050, -1 };
//  	TESTS_RANGE = new int[] { 1, 2049 };
//  	TESTS_RANGE = new int[] { 449, 451 };
//    	TESTS_RANGE = new int[] { 900, 999 };
}

public static Test suite() {
    return buildAllCompliancesTestSuite(testClass());

			"  }\n" +
			"}\n"},
		"----------\n" +
		"1. ERROR in X.java (at line 11)\n" +
		"	while (o == null) {\n" +
		"	       ^\n" +
		"Null comparison always yields false: The variable o cannot be null at this location\n" +
		"----------\n",

			"  }\n" +
			"}"},
		"----------\n" +
		"1. ERROR in X.java (at line 13)\n" +
		"	o.toString();\n" +
		"	^\n" +
		"Potential null pointer access: The variable o may be null at this location\n" +
		"----------\n",

			},
			"");
}
// null analysis -- try/catch
//https://bugs.eclipse.org/bugs/show_bug.cgi?id=302446
public void test0569_try_catch() {
	this.runNegativeTest(
		new String[] {
			"X.java",
			"public class X {\n" +
			"  void foo() {\n" +
			"    Object o = null;\n" +
			"	 int i;\n" +
			"	 if (o == null)\n" +	// redundant check
			"	 	i = 0;\n" +
			"    try {\n" +
			"      System.out.println(i);\n" +  // might throw a runtime exception
			"      o = new Object();\n" +
			"	   throw new Exception(\"Exception thrown from try block\");\n" +
			"    }\n" +
			"    catch (Throwable t) {\n" + // catches everything
			"      return;\n" +             // gets out
			"    }\n" +
			"  }\n" +
			"}\n"},
		"----------\n" + 
		"1. ERROR in X.java (at line 5)\n" + 
		"	if (o == null)\n" + 
		"	    ^\n" + 
		"Redundant null check: The variable o can only be null at this location\n" + 
		"----------\n" + 
		"2. ERROR in X.java (at line 8)\n" + 
		"	System.out.println(i);\n" + 
		"	                   ^\n" + 
		"The local variable i may not have been initialized\n" + 
		"----------\n");
}
// null analysis -- try/catch
//https://bugs.eclipse.org/bugs/show_bug.cgi?id=302446
public void test0570_try_catch() {
	this.runNegativeTest(
		new String[] {
			"X.java",
			"public class X {\n" +
			"  void foo() {\n" +
			"    Object o = null;\n" +
			"	 int i;\n" +
			"	 if (o == null)\n" +	// redundant check
			"	 	i = 0;\n" +
			"    try {\n" +
			"      System.out.println();\n" +  // might throw a runtime exception
			"      o = new Object();\n" +
			"	   if (o != null)\n" +		// redundant check
			"			i = 1\n;" +
			"		throw new Exception(\"Exception thrown from try block\");\n" +
			"    }\n" +
			"    catch (Exception e) {\n" +
			"      if(i == 0)\n" +
			"			System.out.println(\"o was initialised\");\n" +
			"    }\n" +
			"  }\n" +
			"}\n"},
		"----------\n" + 
		"1. ERROR in X.java (at line 5)\n" + 
		"	if (o == null)\n" + 
		"	    ^\n" + 
		"Redundant null check: The variable o can only be null at this location\n" + 
		"----------\n" + 
		"2. ERROR in X.java (at line 10)\n" + 
		"	if (o != null)\n" + 
		"	    ^\n" + 
		"Redundant null check: The variable o cannot be null at this location\n" + 
		"----------\n" + 
		"3. ERROR in X.java (at line 15)\n" + 
		"	if(i == 0)\n" + 
		"	   ^\n" + 
		"The local variable i may not have been initialized\n" + 
		"----------\n");
}
//null analysis -- try/catch
//https://bugs.eclipse.org/bugs/show_bug.cgi?id=302446
public void test0571_try_catch_finally() {
	this.runNegativeTest(
		new String[] {
			"X.java",
			"public class X {\n" +
			"  void foo() {\n" +
			"    Object o = null;\n" +
			"	 int i;\n" +
			"	 if (o == null)\n" +	// redundant check
			"	 	i = 0;\n" +
			"    try {\n" +
			"      o = new Object();\n" +
			"	   i = 1\n;" +
			"	   throw new Exception(\"Exception thrown from try block\");\n" +
			"    }\n" +
			"    catch (Exception e) {\n" +
			"      if(o == null)\n" +
			"			o = new Object();\n" +
			"	   i = 1;\n" +
			"    }\n" +
			"	 finally {\n" +
			"		if (i==1) {\n" +
			"	 		System.out.println(\"Method ended with o being initialised\");\n" +
			"		System.out.println(o.toString());\n" +	// may be null
			"		} \n" +
			"	 }\n" +
			"  }\n" +
			"}\n"},
		"----------\n" + 
		"1. ERROR in X.java (at line 5)\n" + 
		"	if (o == null)\n" + 
		"	    ^\n" + 
		"Redundant null check: The variable o can only be null at this location\n" + 
		"----------\n" + 
		"2. ERROR in X.java (at line 18)\n" + 
		"	if (i==1) {\n" + 
		"	    ^\n" + 
		"The local variable i may not have been initialized\n" + 
		"----------\n" + 
		"3. ERROR in X.java (at line 20)\n" + 
		"	System.out.println(o.toString());\n" + 
		"	                   ^\n" + 
		"Potential null pointer access: The variable o may be null at this location\n" + 
		"----------\n");
}
//null analysis -- if statement
//https://bugs.eclipse.org/bugs/show_bug.cgi?id=302446
public void test0572_if_statement() {
	this.runNegativeTest(
		new String[] {
			"X.java",
			"public class X {\n" + 
			"	void foo() {\n" + 
			"		Object o = null;\n" + 
			"		int i;\n" + 
			"		if (o == null) // redundant check\n" + 
			"			i = 0;\n" + 
			"		System.out.println(i);\n" + 
			"	}\n" + 
			"}\n" + 
			""},
		"----------\n" + 
		"1. ERROR in X.java (at line 5)\n" + 
		"	if (o == null) // redundant check\n" + 
		"	    ^\n" + 
		"Redundant null check: The variable o can only be null at this location\n" + 
		"----------\n" + 
		"2. ERROR in X.java (at line 7)\n" + 
		"	System.out.println(i);\n" + 
		"	                   ^\n" + 
		"The local variable i may not have been initialized\n" + 
		"----------\n");
}
// null analysis - throw
// https://bugs.eclipse.org/bugs/show_bug.cgi?id=201182
public void test0595_throw() {

			"  }\n" +
			"}"},
		"----------\n" +
		"1. ERROR in X.java (at line 6)\n" +
		"	if (o != null) return;\n" +
		"	    ^\n" +
		"Null comparison always yields false: The variable o can only be null at this location\n" +
		"----------\n" +
		"2. ERROR in X.java (at line 7)\n" +
		"	o = null;\n" +
		"	^\n" +
		"Redundant assignment: The variable o can only be null at this location\n" +
		"----------\n",
		JavacTestOptions.Excuse.EclipseWarningConfiguredAsError);
}

public void test1019() {

Return to bug 302446

Lines 1-5 Link Here

(-)compiler/org/eclipse/jdt/internal/compiler/flow/FlowInfo.java (-1 / +72 lines)
1	/*******************************************************************************	1	/*******************************************************************************
2	* Copyright (c) 2000, 2009 IBM Corporation and others.	2	* Copyright (c) 2000, 2010 IBM Corporation and others.
3	* All rights reserved. This program and the accompanying materials	3	* All rights reserved. This program and the accompanying materials
4	* are made available under the terms of the Eclipse Public License v1.0	4	* are made available under the terms of the Eclipse Public License v1.0
5	* which accompanies this distribution, and is available at	5	* which accompanies this distribution, and is available at
Lines 295-300 Link Here
295	}	295	}
296		296
297	/**	297	/**
		298	* Merge if-else branches using optimized boolean conditions
		299	*/
		300	public static UnconditionalFlowInfo mergedOptimizedBranchesIfElse(
		301	FlowInfo initsWhenTrue, boolean isOptimizedTrue,
		302	FlowInfo initsWhenFalse, boolean isOptimizedFalse,
		303	boolean allowFakeDeadBranch, FlowInfo flowInfo) {
		304	UnconditionalFlowInfo mergedInfo;
		305	if (isOptimizedTrue){
		306	if (initsWhenTrue == FlowInfo.DEAD_END && allowFakeDeadBranch) {
		307	mergedInfo = initsWhenFalse.setReachMode(FlowInfo.UNREACHABLE).
		308	unconditionalInits();
		309	}
		310	else {
		311	mergedInfo =
		312	initsWhenTrue.addPotentialInitializationsFrom(initsWhenFalse.
		313	nullInfoLessUnconditionalCopy()).
		314	unconditionalInits();
		315	}
		316	}
		317	else if (isOptimizedFalse) {
		318	if (initsWhenFalse == FlowInfo.DEAD_END && allowFakeDeadBranch) {
		319	mergedInfo = initsWhenTrue.setReachMode(FlowInfo.UNREACHABLE).
		320	unconditionalInits();
		321	}
		322	else {
		323	mergedInfo =
		324	initsWhenFalse.addPotentialInitializationsFrom(initsWhenTrue.
		325	nullInfoLessUnconditionalCopy()).
		326	unconditionalInits();
		327	}
		328	}
		329	else if ((flowInfo.tagBits & FlowInfo.UNREACHABLE) == 0 &&
		330	(initsWhenFalse.tagBits & FlowInfo.UNREACHABLE) != 0 &&
		331	initsWhenTrue != FlowInfo.DEAD_END &&
		332	initsWhenFalse != FlowInfo.DEAD_END) {
		333	// Done when the then branch will always be executed but the condition doesnt have a boolean
		334	// true or false (i.e if(true), etc) for sure
		335	// We don't do this if both if and else branches themselves are in an unreachable code
		336	// or if any of them is a DEAD_END (eg. contains 'return' or 'throws')
		337	mergedInfo =
		338	initsWhenTrue.addPotentialInitializationsFrom(initsWhenFalse.
		339	nullInfoLessUnconditionalCopy()).
		340	unconditionalInits();
		341	// if a variable is only initialized in one branch and not initialized in the other,
		342	// then we need to cast a doubt on its initialization in the merged info
		343	mergedInfo.definiteInits &= initsWhenFalse.unconditionalCopy().definiteInits;
		344
		345	}
		346	else if ((flowInfo.tagBits & FlowInfo.UNREACHABLE) == 0 &&
		347	(initsWhenTrue.tagBits & FlowInfo.UNREACHABLE) != 0 && initsWhenTrue != FlowInfo.DEAD_END
		348	&& initsWhenFalse != FlowInfo.DEAD_END) {
		349	// Done when the else branch will always be executed but the condition doesnt have a boolean
		350	// true or false (i.e if(true), etc) for sure
		351	// We don't do this if both if and else branches themselves are in an unreachable code
		352	// or if any of them is a DEAD_END (eg. contains 'return' or 'throws')
		353	mergedInfo =
		354	initsWhenFalse.addPotentialInitializationsFrom(initsWhenTrue.
		355	nullInfoLessUnconditionalCopy()).
		356	unconditionalInits();
		357	// if a variable is only initialized in one branch and not initialized in the other,
		358	// then we need to cast a doubt on its initialization in the merged info
		359	mergedInfo.definiteInits &= initsWhenTrue.unconditionalCopy().definiteInits;
		360	}
		361	else {
362	mergedInfo = initsWhenTrue.
363	mergedWith(initsWhenFalse.unconditionalInits());
364	}
365	return mergedInfo;
366	}
367
368	/**
298	* Return REACHABLE if this flow info is reachable, UNREACHABLE	369	* Return REACHABLE if this flow info is reachable, UNREACHABLE
299	* else.	370	* else.
300	* @return REACHABLE if this flow info is reachable, UNREACHABLE	371	* @return REACHABLE if this flow info is reachable, UNREACHABLE

Lines 59-70 Link Here

(-)compiler/org/eclipse/jdt/internal/compiler/ast/EqualExpression.java (-6 lines)
59	}	59	}
60	break;	60	break;
61	}	61	}
62	// set the optimize constant to optimize code gen
63	if ((initsWhenTrue.tagBits & FlowInfo.UNREACHABLE) != 0) {
64	this.optimizedBooleanConstant = BooleanConstant.fromValue(false);
65	} else if ((initsWhenFalse.tagBits & FlowInfo.UNREACHABLE) != 0) {
66	this.optimizedBooleanConstant = BooleanConstant.fromValue(true);
67	}
68	// we do not impact enclosing try context because this kind of protection	62	// we do not impact enclosing try context because this kind of protection
69	// does not preclude the variable from being null in an enclosing scope	63	// does not preclude the variable from being null in an enclosing scope
70	}	64	}

Lines 30-36 Link Here

(-)compiler/org/eclipse/jdt/internal/compiler/ast/IfStatement.java (-13 / +35 lines)
30	int elseInitStateIndex = -1;	30	int elseInitStateIndex = -1;
31	int mergedInitStateIndex = -1;	31	int mergedInitStateIndex = -1;
32		32
33	public IfStatement(Expression condition, Statement thenStatement, int sourceStart, int sourceEnd) {	33	public IfStatement(Expression condition, Statement thenStatement, int sourceStart, int sourceEnd) {
34	this.condition = condition;	34	this.condition = condition;
35	this.thenStatement = thenStatement;	35	this.thenStatement = thenStatement;
36	// remember useful empty statement	36	// remember useful empty statement
Lines 69-80 Link Here
69	if (isConditionOptimizedTrue) {	69	if (isConditionOptimizedTrue) {
70	elseFlowInfo.setReachMode(FlowInfo.UNREACHABLE);	70	elseFlowInfo.setReachMode(FlowInfo.UNREACHABLE);
71	}	71	}
		72	if (((flowInfo.tagBits & FlowInfo.UNREACHABLE) == 0) &&
		73	((thenFlowInfo.tagBits & FlowInfo.UNREACHABLE) != 0)) {
		74	// Mark then block as unreachable
		75	// No need if the whole if-else construct itself lies in unreachable code
		76	this.bits \|= ASTNode.IsThenStatementUnreachable;
		77	} else if (((flowInfo.tagBits & FlowInfo.UNREACHABLE) == 0) &&
		78	((elseFlowInfo.tagBits & FlowInfo.UNREACHABLE) != 0)) {
		79	// Mark else block as unreachable
		80	// No need if the whole if-else construct itself lies in unreachable code
		81	this.bits \|= ASTNode.IsElseStatementUnreachable;
		82	}
72	if (this.thenStatement != null) {	83	if (this.thenStatement != null) {
73	// Save info for code gen	84	// Save info for code gen
74	this.thenInitStateIndex = currentScope.methodScope().recordInitializationStates(thenFlowInfo);	85	this.thenInitStateIndex = currentScope.methodScope().recordInitializationStates(thenFlowInfo);
75	if (isConditionOptimizedFalse) {	86	if (isConditionOptimizedFalse \|\| ((this.bits & ASTNode.IsThenStatementUnreachable) == ASTNode.IsThenStatementUnreachable)) {
76	if (!isKnowDeadCodePattern(this.condition) \|\| currentScope.compilerOptions().reportDeadCodeInTrivialIfStatement) {	87	if (!isKnowDeadCodePattern(this.condition) \|\| currentScope.compilerOptions().reportDeadCodeInTrivialIfStatement) {
77	this.thenStatement.complainIfUnreachable(thenFlowInfo, currentScope, initialComplaintLevel);	88	this.thenStatement.complainIfUnreachable(thenFlowInfo, currentScope, initialComplaintLevel);
		89	} else {
		90	// its a known coding pattern which should be tolerated by dead code analysis
		91	// according to isKnowDeadCodePattern()
		92	this.bits &= ~ASTNode.IsThenStatementUnreachable;
78	}	93	}
79	}	94	}
80	thenFlowInfo = this.thenStatement.analyseCode(currentScope, flowContext, thenFlowInfo);	95	thenFlowInfo = this.thenStatement.analyseCode(currentScope, flowContext, thenFlowInfo);
Lines 86-113 Link Here
86		101
87	// process the ELSE part	102	// process the ELSE part
88	if (this.elseStatement != null) {	103	if (this.elseStatement != null) {
89	// signal else clause unnecessarily nested, tolerate else-if code pattern	104	// signal else clause unnecessarily nested, tolerate else-if code pattern
90	if (thenFlowInfo == FlowInfo.DEAD_END	105	if (thenFlowInfo == FlowInfo.DEAD_END
91	&& (this.bits & IsElseIfStatement) == 0 // else of an else-if	106	&& (this.bits & IsElseIfStatement) == 0 // else of an else-if
92	&& !(this.elseStatement instanceof IfStatement)) {	107	&& !(this.elseStatement instanceof IfStatement)) {
93	currentScope.problemReporter().unnecessaryElse(this.elseStatement);	108	currentScope.problemReporter().unnecessaryElse(this.elseStatement);
94	}	109	}
95	// Save info for code gen	110	// Save info for code gen
96	this.elseInitStateIndex = currentScope.methodScope().recordInitializationStates(elseFlowInfo);	111	this.elseInitStateIndex = currentScope.methodScope().recordInitializationStates(elseFlowInfo);
97	if (isConditionOptimizedTrue) {	112	if (isConditionOptimizedTrue \|\| ((this.bits & ASTNode.IsElseStatementUnreachable) != 0)) {
98	if (!isKnowDeadCodePattern(this.condition) \|\| currentScope.compilerOptions().reportDeadCodeInTrivialIfStatement) {	113	if (!isKnowDeadCodePattern(this.condition) \|\| currentScope.compilerOptions().reportDeadCodeInTrivialIfStatement) {
99	this.elseStatement.complainIfUnreachable(elseFlowInfo, currentScope, initialComplaintLevel);	114	this.elseStatement.complainIfUnreachable(elseFlowInfo, currentScope, initialComplaintLevel);
		115	} else {
		116	// its a known coding pattern which should be tolerated by dead code analysis
		117	// according to isKnowDeadCodePattern()
		118	this.bits &= ~ASTNode.IsElseStatementUnreachable;
100	}	119	}
101	}	120	}
102	elseFlowInfo = this.elseStatement.analyseCode(currentScope, flowContext, elseFlowInfo);	121	elseFlowInfo = this.elseStatement.analyseCode(currentScope, flowContext, elseFlowInfo);
103	}	122	}
104	// merge THEN & ELSE initializations	123	// merge THEN & ELSE initializations
105	FlowInfo mergedInfo = FlowInfo.mergedOptimizedBranches(	124	FlowInfo mergedInfo = FlowInfo.mergedOptimizedBranchesIfElse(
106	thenFlowInfo,	125	thenFlowInfo,
107	isConditionOptimizedTrue,	126	isConditionOptimizedTrue,
108	elseFlowInfo,	127	elseFlowInfo,
109	isConditionOptimizedFalse,	128	isConditionOptimizedFalse,
110	true /if(true){ return; } fake-reachable(); /);	129	true /if(true){ return; } fake-reachable(); /,
		130	flowInfo);
111	this.mergedInitStateIndex = currentScope.methodScope().recordInitializationStates(mergedInfo);	131	this.mergedInitStateIndex = currentScope.methodScope().recordInitializationStates(mergedInfo);
112	return mergedInfo;	132	return mergedInfo;
113	}	133	}
Lines 139-145 Link Here
139	if (hasThenPart) {	159	if (hasThenPart) {
140	BranchLabel falseLabel = null;	160	BranchLabel falseLabel = null;
141	// generate boolean condition only if needed	161	// generate boolean condition only if needed
142	if (cst != Constant.NotAConstant && cst.booleanValue() == true) {	162	if (((this.bits & ASTNode.IsElseStatementUnreachable) == ASTNode.IsElseStatementUnreachable) \|\|
		163	(cst != Constant.NotAConstant && cst.booleanValue() == true)) {
143	// No need to generate if condition statement when we know that only the then action	164	// No need to generate if condition statement when we know that only the then action
144	// will be executed	165	// will be executed
145	this.condition.generateCode(currentScope, codeStream, false);	166	this.condition.generateCode(currentScope, codeStream, false);
Lines 180-186 Link Here
180	}	201	}
181	} else if (hasElsePart) {	202	} else if (hasElsePart) {
182	// generate boolean condition only if needed	203	// generate boolean condition only if needed
183	if (cst != Constant.NotAConstant && cst.booleanValue() == false) {	204	if ((this.bits & ASTNode.IsThenStatementUnreachable) == ASTNode.IsThenStatementUnreachable \|\|
		205	(cst != Constant.NotAConstant && cst.booleanValue() == false)) {
184	// No need to generate if condition statement when we know that only the else action	206	// No need to generate if condition statement when we know that only the else action
185	// will be executed	207	// will be executed
186	this.condition.generateCode(currentScope, codeStream, false);	208	this.condition.generateCode(currentScope, codeStream, false);

Lines 26-43 Link Here

(-)src/org/eclipse/jdt/core/tests/compiler/regression/NullReferenceTest.java (-16 / +166 lines)
26	}	26	}
27		27
28	// Static initializer to specify tests subset using TESTS_* static variables	28	// Static initializer to specify tests subset using TESTS_* static variables
29	// All specified tests which does not belong to the class are skipped...	29	// All specified tests which does not belong to the class are skipped...
30	// Only the highest compliance level is run; add the VM argument	30	// Only the highest compliance level is run; add the VM argument
31	// -Dcompliance=1.4 (for example) to lower it if needed	31	// -Dcompliance=1.4 (for example) to lower it if needed
32	static {	32	static {
33	// TESTS_NAMES = new String[] { "test011" };	33	// TESTS_NAMES = new String[] { "test0572_if_statement" };
34	// TESTS_NUMBERS = new int[] { 561 };	34	// TESTS_NUMBERS = new int[] { 561 };
35	// TESTS_NUMBERS = new int[] { 2999 };	35	// TESTS_NUMBERS = new int[] { 2999 };
36	// TESTS_RANGE = new int[] { 2050, -1 };	36	// TESTS_RANGE = new int[] { 2050, -1 };
37	// TESTS_RANGE = new int[] { 1, 2049 };	37	// TESTS_RANGE = new int[] { 1, 2049 };
38	// TESTS_RANGE = new int[] { 449, 451 };	38	// TESTS_RANGE = new int[] { 449, 451 };
39	// TESTS_RANGE = new int[] { 900, 999 };	39	// TESTS_RANGE = new int[] { 900, 999 };
40	}	40	}
41		41
42	public static Test suite() {	42	public static Test suite() {
43	return buildAllCompliancesTestSuite(testClass());	43	return buildAllCompliancesTestSuite(testClass());
Lines 4133-4140 Link Here
4133	" }\n" +	4133	" }\n" +
4134	"}\n"},	4134	"}\n"},
4135	"----------\n" +	4135	"----------\n" +
4136	"1. ERROR in X.java (at line 11)\r\n" +	4136	"1. ERROR in X.java (at line 11)\n" +
4137	" while (o == null) {\r\n" +	4137	" while (o == null) {\n" +
4138	" ^\n" +	4138	" ^\n" +
4139	"Null comparison always yields false: The variable o cannot be null at this location\n" +	4139	"Null comparison always yields false: The variable o cannot be null at this location\n" +
4140	"----------\n",	4140	"----------\n",
Lines 5177-5184 Link Here
5177	" }\n" +	5177	" }\n" +
5178	"}"},	5178	"}"},
5179	"----------\n" +	5179	"----------\n" +
5180	"1. ERROR in X.java (at line 13)\r\n" +	5180	"1. ERROR in X.java (at line 13)\n" +
5181	" o.toString();\r\n" +	5181	" o.toString();\n" +
5182	" ^\n" +	5182	" ^\n" +
5183	"Potential null pointer access: The variable o may be null at this location\n" +	5183	"Potential null pointer access: The variable o may be null at this location\n" +
5184	"----------\n",	5184	"----------\n",
Lines 6054-6060 Link Here
6054	},	6054	},
6055	"");	6055	"");
6056	}	6056	}
6057		6057	// null analysis -- try/catch
		6058	//https://bugs.eclipse.org/bugs/show_bug.cgi?id=302446
		6059	public void test0569_try_catch() {
		6060	this.runNegativeTest(
		6061	new String[] {
		6062	"X.java",
		6063	"public class X {\n" +
		6064	" void foo() {\n" +
		6065	" Object o = null;\n" +
		6066	" int i;\n" +
		6067	" if (o == null)\n" + // redundant check
		6068	" i = 0;\n" +
		6069	" try {\n" +
		6070	" System.out.println(i);\n" + // might throw a runtime exception
		6071	" o = new Object();\n" +
		6072	" throw new Exception(\"Exception thrown from try block\");\n" +
		6073	" }\n" +
		6074	" catch (Throwable t) {\n" + // catches everything
		6075	" return;\n" + // gets out
		6076	" }\n" +
		6077	" }\n" +
		6078	"}\n"},
		6079	"----------\n" +
		6080	"1. ERROR in X.java (at line 5)\n" +
		6081	" if (o == null)\n" +
		6082	" ^\n" +
		6083	"Redundant null check: The variable o can only be null at this location\n" +
		6084	"----------\n" +
		6085	"2. ERROR in X.java (at line 8)\n" +
		6086	" System.out.println(i);\n" +
		6087	" ^\n" +
		6088	"The local variable i may not have been initialized\n" +
		6089	"----------\n");
		6090	}
		6091	// null analysis -- try/catch
		6092	//https://bugs.eclipse.org/bugs/show_bug.cgi?id=302446
		6093	public void test0570_try_catch() {
		6094	this.runNegativeTest(
		6095	new String[] {
		6096	"X.java",
		6097	"public class X {\n" +
		6098	" void foo() {\n" +
		6099	" Object o = null;\n" +
		6100	" int i;\n" +
		6101	" if (o == null)\n" + // redundant check
		6102	" i = 0;\n" +
		6103	" try {\n" +
		6104	" System.out.println();\n" + // might throw a runtime exception
		6105	" o = new Object();\n" +
		6106	" if (o != null)\n" + // redundant check
		6107	" i = 1\n;" +
		6108	" throw new Exception(\"Exception thrown from try block\");\n" +
		6109	" }\n" +
		6110	" catch (Exception e) {\n" +
		6111	" if(i == 0)\n" +
		6112	" System.out.println(\"o was initialised\");\n" +
		6113	" }\n" +
		6114	" }\n" +
		6115	"}\n"},
		6116	"----------\n" +
		6117	"1. ERROR in X.java (at line 5)\n" +
		6118	" if (o == null)\n" +
		6119	" ^\n" +
		6120	"Redundant null check: The variable o can only be null at this location\n" +
		6121	"----------\n" +
6122	"2. ERROR in X.java (at line 10)\n" +
6123	" if (o != null)\n" +
6124	" ^\n" +
6125	"Redundant null check: The variable o cannot be null at this location\n" +
6126	"----------\n" +
6127	"3. ERROR in X.java (at line 15)\n" +
6128	" if(i == 0)\n" +
6129	" ^\n" +
6130	"The local variable i may not have been initialized\n" +
6131	"----------\n");
6132	}
6133	//null analysis -- try/catch
6134	//https://bugs.eclipse.org/bugs/show_bug.cgi?id=302446
6135	public void test0571_try_catch_finally() {
6136	this.runNegativeTest(
6137	new String[] {
6138	"X.java",
6139	"public class X {\n" +
6140	" void foo() {\n" +
6141	" Object o = null;\n" +
6142	" int i;\n" +
6143	" if (o == null)\n" + // redundant check
6144	" i = 0;\n" +
6145	" try {\n" +
6146	" o = new Object();\n" +
6147	" i = 1\n;" +
6148	" throw new Exception(\"Exception thrown from try block\");\n" +
6149	" }\n" +
6150	" catch (Exception e) {\n" +
6151	" if(o == null)\n" +
6152	" o = new Object();\n" +
6153	" i = 1;\n" +
6154	" }\n" +
6155	" finally {\n" +
6156	" if (i==1) {\n" +
6157	" System.out.println(\"Method ended with o being initialised\");\n" +
6158	" System.out.println(o.toString());\n" + // may be null
6159	" } \n" +
6160	" }\n" +
6161	" }\n" +
6162	"}\n"},
6163	"----------\n" +
6164	"1. ERROR in X.java (at line 5)\n" +
6165	" if (o == null)\n" +
6166	" ^\n" +
6167	"Redundant null check: The variable o can only be null at this location\n" +
6168	"----------\n" +
6169	"2. ERROR in X.java (at line 18)\n" +
6170	" if (i==1) {\n" +
6171	" ^\n" +
6172	"The local variable i may not have been initialized\n" +
6173	"----------\n" +
6174	"3. ERROR in X.java (at line 20)\n" +
6175	" System.out.println(o.toString());\n" +
6176	" ^\n" +
6177	"Potential null pointer access: The variable o may be null at this location\n" +
6178	"----------\n");
6179	}
6180	//null analysis -- if statement
6181	//https://bugs.eclipse.org/bugs/show_bug.cgi?id=302446
6182	public void test0572_if_statement() {
6183	this.runNegativeTest(
6184	new String[] {
6185	"X.java",
6186	"public class X {\n" +
6187	" void foo() {\n" +
6188	" Object o = null;\n" +
6189	" int i;\n" +
6190	" if (o == null) // redundant check\n" +
6191	" i = 0;\n" +
6192	" System.out.println(i);\n" +
6193	" }\n" +
6194	"}\n" +
6195	""},
6196	"----------\n" +
6197	"1. ERROR in X.java (at line 5)\n" +
6198	" if (o == null) // redundant check\n" +
6199	" ^\n" +
6200	"Redundant null check: The variable o can only be null at this location\n" +
6201	"----------\n" +
6202	"2. ERROR in X.java (at line 7)\n" +
6203	" System.out.println(i);\n" +
6204	" ^\n" +
6205	"The local variable i may not have been initialized\n" +
6206	"----------\n");
6207	}
6058	// null analysis - throw	6208	// null analysis - throw
6059	// https://bugs.eclipse.org/bugs/show_bug.cgi?id=201182	6209	// https://bugs.eclipse.org/bugs/show_bug.cgi?id=201182
6060	public void test0595_throw() {	6210	public void test0595_throw() {
Lines 8975-8991 Link Here
8975	" }\n" +	9125	" }\n" +
8976	"}"},	9126	"}"},
8977	"----------\n" +	9127	"----------\n" +
8978	"1. ERROR in X.java (at line 6)\r\n" +	9128	"1. ERROR in X.java (at line 6)\n" +
8979	" if (o != null) return;\r\n" +	9129	" if (o != null) return;\n" +
8980	" ^\n" +	9130	" ^\n" +
8981	"Null comparison always yields false: The variable o can only be null at this location\n" +	9131	"Null comparison always yields false: The variable o can only be null at this location\n" +
8982	"----------\n" +	9132	"----------\n" +
8983	"2. ERROR in X.java (at line 7)\r\n" +	9133	"2. ERROR in X.java (at line 7)\n" +
8984	" o = null;\r\n" +	9134	" o = null;\n" +
8985	" ^\n" +	9135	" ^\n" +
8986	"Redundant assignment: The variable o can only be null at this location\n" +	9136	"Redundant assignment: The variable o can only be null at this location\n" +
8987	"----------\n",	9137	"----------\n",
8988	JavacTestOptions.Excuse.EclipseWarningConfiguredAsError);	9138	JavacTestOptions.Excuse.EclipseWarningConfiguredAsError);
8989	}	9139	}
8990		9140
8991	public void test1019() {	9141	public void test1019() {

Lines 1-5 Link Here

(-)compiler/org/eclipse/jdt/internal/compiler/ast/ASTNode.java (-3 / +5 lines)
1	/*******************************************************************************	1	/*******************************************************************************
2	* Copyright (c) 2000, 2009 IBM Corporation and others.	2	* Copyright (c) 2000, 2010 IBM Corporation and others.
3	* All rights reserved. This program and the accompanying materials	3	* All rights reserved. This program and the accompanying materials
4	* are made available under the terms of the Eclipse Public License v1.0	4	* are made available under the terms of the Eclipse Public License v1.0
5	* which accompanies this distribution, and is available at	5	* which accompanies this distribution, and is available at
Lines 30-37 Link Here
30	public final static int Bit5 = 0x10; // value for return (expression) \| has all method bodies (unit) \| supertype ref (type ref) \| resolved (field decl)	30	public final static int Bit5 = 0x10; // value for return (expression) \| has all method bodies (unit) \| supertype ref (type ref) \| resolved (field decl)
31	public final static int Bit6 = 0x20; // depth (name ref, msg) \| ignore need cast check (cast expression) \| error in signature (method declaration/ initializer) \| is recovered (annotation reference)	31	public final static int Bit6 = 0x20; // depth (name ref, msg) \| ignore need cast check (cast expression) \| error in signature (method declaration/ initializer) \| is recovered (annotation reference)
32	public final static int Bit7 = 0x40; // depth (name ref, msg) \| operator (operator) \| need runtime checkcast (cast expression) \| label used (labelStatement) \| needFreeReturn (AbstractMethodDeclaration)	32	public final static int Bit7 = 0x40; // depth (name ref, msg) \| operator (operator) \| need runtime checkcast (cast expression) \| label used (labelStatement) \| needFreeReturn (AbstractMethodDeclaration)
33	public final static int Bit8 = 0x80; // depth (name ref, msg) \| operator (operator) \| unsafe cast (cast expression) \| is default constructor (constructor declaration)	33	public final static int Bit8 = 0x80; // depth (name ref, msg) \| operator (operator) \| unsafe cast (cast expression) \| is default constructor (constructor declaration) \| isElseStatementUnreachable (if statement)
34	public final static int Bit9 = 0x100; // depth (name ref, msg) \| operator (operator) \| is local type (type decl)	34	public final static int Bit9 = 0x100; // depth (name ref, msg) \| operator (operator) \| is local type (type decl) \| isThenStatementUnreachable (if statement)
35	public final static int Bit10= 0x200; // depth (name ref, msg) \| operator (operator) \| is anonymous type (type decl)	35	public final static int Bit10= 0x200; // depth (name ref, msg) \| operator (operator) \| is anonymous type (type decl)
36	public final static int Bit11 = 0x400; // depth (name ref, msg) \| operator (operator) \| is member type (type decl)	36	public final static int Bit11 = 0x400; // depth (name ref, msg) \| operator (operator) \| is member type (type decl)
37	public final static int Bit12 = 0x800; // depth (name ref, msg) \| operator (operator) \| has abstract methods (type decl)	37	public final static int Bit12 = 0x800; // depth (name ref, msg) \| operator (operator) \| has abstract methods (type decl)
Lines 194-199 Link Here
194	// for if statement	194	// for if statement
195	public static final int IsElseIfStatement = Bit30;	195	public static final int IsElseIfStatement = Bit30;
196	public static final int ThenExit = Bit31;	196	public static final int ThenExit = Bit31;
		197	public static final int IsElseStatementUnreachable = Bit8;
		198	public static final int IsThenStatementUnreachable = Bit9;
197		199
198	// for type reference	200	// for type reference
199	public static final int IsSuperType = Bit5;	201	public static final int IsSuperType = Bit5;