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Using latest in 1.4 compliance mode, the following code leads to a VerifyError. public class X { int test(boolean b) { int i; try { if (b) { i = 1; return 1; } i = 2; } finally { if (b) i = 3; } return i; } public static void main(String[] args) { X t = new X(); t.test(false); } }
I believe this is a bug in the bytecode verified when handling subroutines. jikes also produces a .class file that fails to verify when using jsr/ret bytecodes. javac 1.3.1 has the same bug. If javac 1.5.0 is used. Subroutines are inlined and the error doesn't occur. When using Eclipse compiler in 1.5 compliance mode, the subroutines are inlined and the code doesn't fail anymore. Using the 1.4 compliance mode with the -inlineJSR option fixes it. I can successfully run a .class file that is using jsr/ret bytecodes using a J9 VM. I don't see anything wrong with the bytecodes so I would be tempted to close as a bytecode verifier problem.
Also note that javac 1.4.2_08 is also performing JSR inlining, thus hiding this issue. When JSR opcodes are generated, we produce: // Method descriptor #15 (Z)I // Stack: 1, Locals: 5 int test(boolean b); 0 iload_1 [b] 1 ifeq 11 4 iconst_1 5 istore_2 [i] 6 jsr 24 9 iconst_1 10 ireturn 11 iconst_2 12 istore_2 [i] 13 goto 33 16 astore 4 18 jsr 24 21 aload 4 23 athrow 24 astore_3 25 iload_1 [b] 26 ifeq 31 29 iconst_3 30 istore_2 31 ret 3 33 jsr 24 36 iload_2 [i] 37 ireturn Exception Table: [pc: 0, pc: 9] -> 16 when : any [pc: 11, pc: 16] -> 16 when : any [pc: 33, pc: 36] -> 16 when : any Local variable table: [pc: 0, pc: 38] local: this index: 0 type: X [pc: 0, pc: 38] local: b index: 1 type: boolean [pc: 6, pc: 11] local: i index: 2 type: int [pc: 13, pc: 16] local: i index: 2 type: int [pc: 36, pc: 38] local: i index: 2 type: int where javac [1.3.1] is producing // Method descriptor #11 (Z)I // Stack: 1, Locals: 6 int test(boolean arg); 0 iload_1 1 ifeq 13 4 iconst_1 5 istore_2 6 iconst_1 7 istore_3 8 jsr 29 11 iload_3 12 ireturn 13 iconst_2 14 istore_2 15 jsr 29 18 goto 39 21 astore 4 23 jsr 29 26 aload 4 28 athrow 29 astore 5 31 iload_1 32 ifeq 37 35 iconst_3 36 istore_2 37 ret 5 39 iload_2 40 ireturn Exception Table: [pc: 0, pc: 21] -> 21 when : any Line numbers: [pc: 0, line: 5] [pc: 4, line: 6] [pc: 6, line: 7] [pc: 13, line: 9] [pc: 21, line: 11] [pc: 35, line: 12] [pc: 39, line: 14] and both are rejected by a Sun 1.4.2 VM bytecode verifier.
Both generated classfiles are flagged with following verify error: Exception in thread "main" java.lang.VerifyError: (class: X, method: test signature: (Z)I) Register 2 contains wrong type
This is a known VM bug, also see: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4381996 Other VMs do not have this bug (like J9).
*** Bug 115636 has been marked as a duplicate of this bug. ***
