Attachment #174767 for bug #320170




			// prot. non null
		& ((a2 = this.nullBit2) | (a4 = this.nullBit4));
			// null or unknown
	m2 = s1 & (s2 = this.nullBit2) & (s3 ^ s4) // TODO(stephan): potential typo: should this be "s2 = source.nullBit2"???
			// prot. null
		& ((a3 = this.nullBit3) | a4);
			// non null or unknown

		source.nullBit2 &= (nm1 = ~m1) & ((nm2 = ~m2) | a4);
		source.nullBit3 &= (nm1 | a2) & nm2;
		source.nullBit4 &= nm1 & nm2;
		// any variable that is (pot n, pot nn, pot un) at end of try (as captured by *this* NullInfoRegistry)
		// has the same uncertainty also for the mitigated case (function result)
		// see https://bugs.eclipse.org/bugs/show_bug.cgi?id=320170 -  [compiler] [null] Whitebox issues in null analysis
		// and org.eclipse.jdt.core.tests.compiler.regression.NullReferenceTest.test0536_try_finally()
		long x = ~this.nullBit1 & a2 & a3 & a4; // x is set for all variable ids that have state 0111 (pot n, pot nn, pot un)
		if (x != 0) {
			// restore state 0111 for all variable ids in x:
			source.nullBit1 &= ~x;
			source.nullBit2 |= x;
			source.nullBit3 |= x;
			source.nullBit4 |= x;
		}
	}
	if (this.extra != null && source.extra != null) {
		int length = this.extra[2].length, sourceLength = source.extra[0].length;

Lines 63-68 Link Here

(-)compiler/org/eclipse/jdt/internal/compiler/flow/UnconditionalFlowInfo.java (+1 lines)
63	0100 pot. null	63	0100 pot. null
64	0101 pot. n & pot. un	64	0101 pot. n & pot. un
65	0110 pot. n & pot. nn	65	0110 pot. n & pot. nn
		66	0111 pot. n & pot. nn & pot. un
66	1001 def. unknown	67	1001 def. unknown
67	1010 def. non null	68	1010 def. non null
68	1011 pot. nn & prot. nn	69	1011 pot. nn & prot. nn

Lines 96-102 Link Here

(-)src/org/eclipse/jdt/core/tests/compiler/regression/NullReferenceImplTests.java (-1 / +1 lines)
96	011001	96	011001
97	011010	97	011010
98	011011	98	011011
99	011100	99	011100 pot. n & pot. nn & pot. un
100	011101	100	011101
101	011110	101	011110
102	011111	102	011111




			"");
}

// null analysis -- try/finally
// https://bugs.eclipse.org/bugs/show_bug.cgi?id=320170 -  [compiler] [null] Whitebox issues in null analysis
// trigger nullbits 0111 (pot n|nn|un), don't let "definitely unknown" override previous information
public void test0536_try_finally() {
	this.runNegativeTest(
		new String[] {
			"X.java",
			"public class X {\n" +
			" X bar () { return null; }\n" +
			" void foo() {\n" +
			"   X x = new X();\n" +
			"   try {\n" +
			"     x = null;\n" +
			"     x = new X();\n" +  // if this throws an exception finally finds x==null
			"     x = bar();\n" +
			"   } finally {\n" +
			"     x.toString();\n" + // complain
			"   }\n" +
			" }\n" +
			"}\n"},
		"----------\n" + 
		"1. ERROR in X.java (at line 10)\n" + 
		"	x.toString();\n" + 
		"	^\n" + 
		"Potential null pointer access: The variable x may be null at this location\n" + 
		"----------\n",
	    JavacTestOptions.Excuse.EclipseWarningConfiguredAsError);
}

// null analysis -- try/catch
public void test0550_try_catch() {
	this.runConformTest(

Return to bug 320170

Lines 319-325 Link Here

(-)compiler/org/eclipse/jdt/internal/compiler/flow/NullInfoRegistry.java (-1 / +13 lines)
319	// prot. non null	319	// prot. non null
320	& ((a2 = this.nullBit2) \| (a4 = this.nullBit4));	320	& ((a2 = this.nullBit2) \| (a4 = this.nullBit4));
321	// null or unknown	321	// null or unknown
322	m2 = s1 & (s2 = this.nullBit2) & (s3 ^ s4)	322	m2 = s1 & (s2 = this.nullBit2) & (s3 ^ s4) // TODO(stephan): potential typo: should this be "s2 = source.nullBit2"???
323	// prot. null	323	// prot. null
324	& ((a3 = this.nullBit3) \| a4);	324	& ((a3 = this.nullBit3) \| a4);
325	// non null or unknown	325	// non null or unknown
Lines 336-341 Link Here
336	source.nullBit2 &= (nm1 = ~m1) & ((nm2 = ~m2) \| a4);	336	source.nullBit2 &= (nm1 = ~m1) & ((nm2 = ~m2) \| a4);
337	source.nullBit3 &= (nm1 \| a2) & nm2;	337	source.nullBit3 &= (nm1 \| a2) & nm2;
338	source.nullBit4 &= nm1 & nm2;	338	source.nullBit4 &= nm1 & nm2;
		339	// any variable that is (pot n, pot nn, pot un) at end of try (as captured by this NullInfoRegistry)
		340	// has the same uncertainty also for the mitigated case (function result)
		341	// see https://bugs.eclipse.org/bugs/show_bug.cgi?id=320170 - [compiler] [null] Whitebox issues in null analysis
		342	// and org.eclipse.jdt.core.tests.compiler.regression.NullReferenceTest.test0536_try_finally()
		343	long x = ~this.nullBit1 & a2 & a3 & a4; // x is set for all variable ids that have state 0111 (pot n, pot nn, pot un)
		344	if (x != 0) {
		345	// restore state 0111 for all variable ids in x:
		346	source.nullBit1 &= ~x;
		347	source.nullBit2 \|= x;
		348	source.nullBit3 \|= x;
		349	source.nullBit4 \|= x;
		350	}
339	}	351	}
340	if (this.extra != null && source.extra != null) {	352	if (this.extra != null && source.extra != null) {
341	int length = this.extra[2].length, sourceLength = source.extra[0].length;	353	int length = this.extra[2].length, sourceLength = source.extra[0].length;

Lines 5484-5489 Link Here

(-)src/org/eclipse/jdt/core/tests/compiler/regression/NullReferenceTest.java (+29 lines)
5484	"");	5484	"");
5485	}	5485	}
5486		5486
		5487	// null analysis -- try/finally
		5488	// https://bugs.eclipse.org/bugs/show_bug.cgi?id=320170 - [compiler] [null] Whitebox issues in null analysis
		5489	// trigger nullbits 0111 (pot n\|nn\|un), don't let "definitely unknown" override previous information
		5490	public void test0536_try_finally() {
		5491	this.runNegativeTest(
		5492	new String[] {
		5493	"X.java",
		5494	"public class X {\n" +
		5495	" X bar () { return null; }\n" +
		5496	" void foo() {\n" +
		5497	" X x = new X();\n" +
		5498	" try {\n" +
		5499	" x = null;\n" +
		5500	" x = new X();\n" + // if this throws an exception finally finds x==null
		5501	" x = bar();\n" +
		5502	" } finally {\n" +
		5503	" x.toString();\n" + // complain
		5504	" }\n" +
		5505	" }\n" +
		5506	"}\n"},
		5507	"----------\n" +
		5508	"1. ERROR in X.java (at line 10)\n" +
		5509	" x.toString();\n" +
		5510	" ^\n" +
		5511	"Potential null pointer access: The variable x may be null at this location\n" +
		5512	"----------\n",
		5513	JavacTestOptions.Excuse.EclipseWarningConfiguredAsError);
		5514	}
		5515
5487	// null analysis -- try/catch	5516	// null analysis -- try/catch
5488	public void test0550_try_catch() {	5517	public void test0550_try_catch() {
5489	this.runConformTest(	5518	this.runConformTest(