open jdk debug options

[Neo Jia]

On Tue, Oct 7, 2008 at 10:05 PM, Jon Masamitsu <Jon.Masamitsu at sun.com> wrote:
>
> When you start
>
> dbx java
>
> you are starting dbx on the java launcher.  The
> launcher does an exec of the VM.
> In the output below from dbx the "stopped in main"
> indicates that the exec has happened and  you've
> stopped in the main of the VM.  At that point
> dbx has forgotten about the breakpoints you've
> set because it thinks the breakpoints are in the
> launcher.

FYI. gdb can keep follow the exec after 6.5.

Thanks,
Neo

>
> You need to set your LD_LIBRARY_PATH
> to point to the libjvm.so that you've built.
>
> Compile this program
>
> public class PrintLibraryPath {
>   public static void main(String[] args) {
>      System.out.println(System.getProperty("java.library.path"));
>   }
> }
>
> and execute it with the java you want to debug.
>
> I have /usr/jdk/jdk1.5.0_11/bin/java so
>
> -------------------
> /usr/jdk/jdk1.5.0_11/bin/java PrintLibraryPath
> /usr/jdk/instances/jdk1.5.0/jre/lib/sparc/server:/usr/jdk/instances/jdk1.5.0/jre/lib/sparc:/usr/jdk/instances/jdk1.5.0/jre/../lib/sparc:/usr/lib
> -------------------
>
> prints the LD_LIBRARY_PATH for /usr/jdk/jdk1.5.0_11/bin/java
>
> Set your LD_LIBRARY_PATH accordingly.
>
> Then start dbx on java and you should see something like
>
> -------------------
> dbx /usr/jdk/jdk1.5.0_11/bin/java
> For information about new features see `help changes'
> To remove this message, put `dbxenv suppress_startup_message 7.5' in your
> .dbxrcReading java
> Reading ld.so.1
> Reading libthread.so.1
> Reading libdl.so.1
> Reading libc.so.1
> -------------------
>
> Run with -version
>
> -------------------
>
> dbx: run -version
> Running: java -version
> (process id 6309)
> Reading libc_psr.so.1
> Reading libjvm.so
> Reading libsocket.so.1
> Reading libsched.so.1
> Reading libCrun.so.1
> Reading libm.so.1
> Reading libnsl.so.1
> Reading libm.so.2
> Reading libscf.so.1
> Reading libdoor.so.1
> Reading libuutil.so.1
> Reading libmd5.so.1
> Reading libmd5_psr.so.1
> Reading libmp.so.2
> Reading libhpi.so
> Reading libverify.so
> Reading libjava.so
> Reading libzip.so
> java version "1.5.0_11"
> Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_11-b03)
> Java HotSpot(TM) Server VM (build 1.5.0_11-b03, mixed mode)
>
> execution completed, exit code is 0
> dbx:
> -------------------
>
> Running with -version causes the VM to execute and all the
> libraries get loaded.  You should them see your
>
> /scratch/wang/java_tm_7/lib/sparc/server/libjvm.so
>
> You should be able to set your breakpoints now and run
> with your real java command line.
>
>
> Cong Wang wrote:
>>
>> Hi Jon:
>>    I went into the  ALT_OUTPUTDIR/bin
>> start dbx with :
>> dbx java
>> For information about new features see `help changes'
>> To remove this message, put `dbxenv suppress_startup_message 7.6' in your
>> .dbxrc
>> Reading java
>> Reading /usr/lib/ld.so.1
>> Reading /lib/libthread.so.1
>> Reading /scratch/wang/java_tm_7/lib/sparc/jli/libjli.so
>> Reading /lib/libdl.so.1
>> Reading /lib/libc.so.1
>>
>> then I map the src file foler into the current folder, using pathmap
>>
>> pathmap /scratch/wang/openjdk/hotspot/src/cpu/sparc/vm
>> /scratch/wang/java_tm_7/bin
>>
>> after the pathmap, I try to find the function using
>>
>> whereis compiler_lock_object
>>
>> there is no output.
>>
>> But I know that function is in
>> /scratch/wang/java_tm_7/lib/sparc/server/libjvm.so, therefore
>> I use the following to load the shared library:
>> loadobject -load /scratch/wang/java_tm_7/lib/sparc/server/libjvm.so
>> Reading /scratch/wang/java_tm_7/lib/sparc/server/libjvm.so
>> Loaded loadobject: /scratch/wang/java_tm_7/lib/sparc/server/libjvm.so
>>
>> now, when I use whereis to find compiler_lock_object, I got:
>>  whereis compiler_lock_object
>> function:
>>
>> `/scratch/wang/java_tm_7/lib/sparc/server/libjvm.so`assembler_sparc.cpp`#__1cOMacroAssemblerUcompiler_lock_object6MpnMRegisterImpl_222pnVBiasedLockingCounters__v_
>>     [non -g, demangles to:
>>
>> MacroAssembler::compiler_lock_object(RegisterImpl*,RegisterImpl*,RegisterImpl*,RegisterImpl*,BiasedLockingCounters*)]
>>
>> Then, I set a break point using:
>> stop in compiler_lock_object
>> dbx: warning: 'compiler_lock_object' has no debugger info -- will
>> trigger on first instruction
>> (2) stop in
>> MacroAssembler::compiler_lock_object(RegisterImpl*,RegisterImpl*,RegisterImpl*,RegisterImpl*,BiasedLockingCounters*)
>>
>>
>> So, I run my application in the debugger
>> using:
>>
>> run -server -Xcomp -Xbatch -Xss128k -XX:NewSize=256m -Xnoclassgc
>> -verbose:gc -classpath /scratch/wang/java_tm_7/bin/
>> SynchronizedCounter
>>
>> (process id 25142)
>> dbx: process 25142 about to exec("/scratch/wang/java_tm_7/bin/java")
>> dbx: program "/scratch/wang/java_tm_7/bin/java" just exec'ed
>> dbx: to go back to the original program use "debug $oprog"
>> t at 1 (l at 1) stopped in main at 0x00010d30
>> 0x00010d30: main       :        save     %sp, -128, %sp
>>
>> (dbx) cont
>> t at 2 (l at 2) signal SEGV (no mapping at the fault address) in (unknown)
>> at 0xfc063710
>> 0xfc063710:     ld       [%o0 + 4], %l0
>> Current function is jni_invoke_nonstatic (optimized)
>>  1084     JavaCalls::call(result, method, &java_args, CHECK);
>>
>> I will never get to my break point. But if I run this outside dbx,
>> everything works fine.
>>
>> SynchronizedCounter is a small multi-threaed java program I wrote to
>> test the jvm. It has two threads try to grab a lock and increment a
>> shared counter.
>> It works fine but I want to change how the jvm manages the lock, so I
>> want to stop the program when jvm creates a lock and acquires it.
>>
>> Thanks for any comment you may have in advance.
>>
>> Regards
>> James Wang
>>
>>
>> On Tue, Oct 7, 2008 at 10:03 PM, Jon Masamitsu <Jon.Masamitsu at sun.com>
>> wrote:
>>
>>>
>>> How do you start dbx on java?  And what is dbx saying
>>> exactly?
>>>
>>> Cong Wang wrote:
>>>
>>>>
>>>> Hi all:
>>>>  I am trying to modify some part of the hotspot runtime interpreter
>>>> and I would like to debug that using either dbx or gdb. I have compile
>>>> the file using the following options:
>>>>
>>>> ALT_BINARY_PLUGS_PATH=/scratch/wang/openjdk-binary-plugs
>>>> ALT_FREETYPE_LIB_PATH=/usr/local/lib
>>>> ALT_FREETYPE_HEADERS_PATH=/usr/local/include
>>>> ALT_CUPS_HEADERS_PATH=/scratch/wang/cups-1.3.8
>>>> ANT_HOME=/usr/sfw
>>>> ALT_OUTPUTDIR=/scratch/wang/java_tm_7
>>>> DEV_ONLY=true
>>>> DEBUG=true
>>>>
>>>>   I am not able to use dbx to debug java in the ALT_OUTPUTDIR/bin
>>>> directory. I would like to set a break point at
>>>> hotspot/src/cpu/sparc/vm/assembler_sparc.cpp
>>>> MacroAssembler::compiler_lock_object function. I have tried to use the
>>>> dbx pathmap command but it doesn't seem to help dbx to locate the
>>>> source file or the function definition.
>>>>  Any suggestions? Thanks in advance for any comment.
>>>>
>>>>
>>>>
>>>
>>>
>>
>>
>>
>>
>
>



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probably today we haven't the technology we are using!