IndexoutofBounds Exception when instrumenting some class files.

[vihari]

unifi.drivers.Analyze INFO: Instrumenting method edu.stanford.muse.email.EmailFetcherThread.run()V
:::: aload_244 ::: 239 //This is the instruction and byte code offset respectively
?? idx = 7 no.of words : 1 local vars length: 4
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 6
at unifi.MethodUnits.get_local_var_unit(MethodUnits.java:459)
at unifi.drivers.Instrumenter.instrumentMethod(Instrumenter.java:359)
at unifi.drivers.Instrumenter.instrumentClass(Instrumenter.java:161)
at unifi.drivers.Instrumenter.instrumentJar(Instrumenter.java:87)
at unifi.drivers.Instrumenter.main(Instrumenter.java:473)
where one expects an idx of 2 in the above case.

[vihari]

This is a simple rather hacky fix, where the index in local var table is extracted from the instruction rather than
int indx = lv_map.pos_to_logical_LV_num (oPos);
There seems to be a bug in pos_to_logical_LV_num function.
With this modification muse was successfully instrumented, there are still some problems with instrumenting which is when observed with socialite and is discussed in issue #2.

[vihari]

Consider this
unifi.drivers.Analyze INFO: Instrumenting method socialite.dist.worker.WorkerNode.run()V
Method max locals 7
//pos, physical index in lvtable and logical index
::: 0 ::: 0 :::logical::: 0
::: 241 ::: 0 :::logical::: 0
::: 87 ::: 0 :::logical::: 0
::: 127 ::: 0 :::logical::: 0
::: 192 ::: 0 :::logical::: 0
::: 201 ::: 0 :::logical::: 0
::: 11 ::: 1 :::logical::: 1
::: 267 ::: 1 :::logical::: 7
::: 279 ::: 1 :::logical::: 7
::: 18 ::: 2 :::logical::: 2
::: 27 ::: 2 :::logical::: 2
::: 37 ::: 2 :::logical::: 2
::: 43 ::: 3 :::logical::: 3
::: 80 ::: 3 :::logical::: 3
::: 65 ::: 3 :::logical::: 3
::: 98 ::: 3 :::logical::: 3
::: 91 ::: 3 :::logical::: 3
::: 226 ::: 3 :::logical::: 3
::: 105 ::: 3 :::logical::: 3
::: 117 ::: 4 :::logical::: 4
::: 131 ::: 4 :::logical::: 4
::: 136 ::: 4 :::logical::: 4
::: 185 ::: 4 :::logical::: 4
::: 183 ::: 5 :::logical::: 5
::: 163 ::: 6 :::logical::: 6
::: 196 ::: 6 :::logical::: 8
:::: aload_345 ::: 65
??????????? idx = 3 no.of words : 1 local vars length: 4 real local vars: 4
:::: aload25 6 ::: 163
??????????? idx = 6 no.of words : 1 local vars length: 4 real local vars: 4
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 5
at unifi.MethodUnits.get_local_var_unit(MethodUnits.java:462)
at unifi.drivers.Instrumenter.instrumentMethod(Instrumenter.java:389)
at unifi.drivers.Instrumenter.instrumentClass(Instrumenter.java:164)
at unifi.drivers.Instrumenter.instrumentJar(Instrumenter.java:90)
at unifi.drivers.Instrumenter.main(Instrumenter.java:503)

real_locals value is 4 and hence the size of local_vars. While the right answer seems to be 8.
Line 286 MethodUnits.java
// TOFIX: why do we add +2 here ?
//+2 because lv is 0 based index and n_param_words>=1 because of "this" param
int max_local_words = lv_map.highest_lv () + 2;
real_locals = max_local_words - _n_param_words;