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http://nagoya.apache.org/bugzilla/show_bug.cgi?id=26049 Incorrect verification of class files Summary: Incorrect verification of class files Product: BCEL Version: 5.1 Platform: PC OS/Version: Linux Status: NEW Severity: Normal Priority: Other Component: Main AssignedTo: [EMAIL PROTECTED] ReportedBy: [EMAIL PROTECTED] Hi, JustIce indicates that the storing of a newly created object in a local before calling it's constructor as an error. However, this is incorrect as the local is not accessed along any control flow path before the constructor is called. This is also safe in a multithreaded setting. Also, the same class file is well interpreted by java interpreters from SUN, Blackdown, and IBM. Moreover, there is no restriction on handling (not using) of uninitialized objects in the JVM spec. ASM output of the correponding class file and JustIce' output are inlined. public static main ([Ljava/lang/String;)V NEW excpsync ASTORE 1 ALOAD 1 INVOKESPECIAL excpsync <init> ()V ALOAD 1 ASTORE 1 NEW java/lang/Thread ASTORE 2 ALOAD 2 ALOAD 1 INVOKESPECIAL java/lang/Thread <init> (Ljava/lang/Runnable;)V ALOAD 2 INVOKEVIRTUAL java/lang/Thread start ()V NEW java/lang/Thread ASTORE 2 NEW f ASTORE 3 ALOAD 3 INVOKESPECIAL f <init> ()V ALOAD 2 ALOAD 3 INVOKESPECIAL java/lang/Thread <init> (Ljava/lang/Runnable;)V ALOAD 2 INVOKEVIRTUAL java/lang/Thread start ()V LDC "Hi" ASTORE 2 ALOAD 1 ALOAD 2 PUTFIELD excpsync o Ljava/lang/String; ALOAD 2 PUTSTATIC excpsync t Ljava/lang/String; RETURN MAXSTACK = 2 MAXLOCALS = 4 JustIce by Enver Haase, (C) 2001-2002. <http://bcel.sourceforge.net> <http://jakarta.apache.org/bcel> Now verifying: excpsync Pass 1: VERIFIED_OK Passed verification. Pass 2: VERIFIED_OK Passed verification. Pass 3a, method number 0 ['public void <init>()']: VERIFIED_OK Passed verification. Pass 3b, method number 0 ['public void <init>()']: VERIFIED_OK Passed verification. Pass 3a, method number 1 ['public static void main(String[] arg0)']: VERIFIED_OK Passed verification. Pass 3b, method number 1 ['public static void main(String[] arg0)']: VERIFIED_REJECTED Constraint violated in method 'public static void main(String[] arg0)': Instruction ASTORE constraint violated: Working on an uninitialized object '<UNINITIALIZED OBJECT OF TYPE 'excpsync'>'. InstructionHandle: 3: astore_1[76](1) Execution Frame: Local Variables: 0: java.lang.String[] 1: <unknown object> 2: <unknown object> 3: <unknown object> OperandStack: Slots used: 1 MaxStack: 2. <UNINITIALIZED OBJECT OF TYPE 'excpsync'> (Size: 1) Execution flow: 0: new 12 [InstructionContext] 3: astore_1 [InstructionContext] Pass 3a, method number 2 ['public void run()']: VERIFIED_OK Passed verification. Pass 3b, method number 2 ['public void run()']: VERIFIED_OK Passed verification. --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
