6953477: review request for portability improvements to Hotspot

[Tom Rodriguez]

On Jul 29, 2010, at 7:36 PM, David Holmes wrote:

> Hi Tom,
> 
> Thanks for the close scrutiny.
> 
> Tom Rodriguez said the following on 07/30/10 03:18:
>> The print_location changes in os::print_context are interesting, if a
>> little verbose.  Do you have an example of what the output will look
>> like?
> 
> Internally there are some examples in the CR for 6889724. I also posted something below.
> 
>> You should make equivalent changes in os_windows_x86.cpp too.
> 
> Ideally yes, but at the time, as now, I had no access to Windows boxes for building or testing this.

jprt always builds windows and I'm not sure how much testing this needs.  The print_location code itself is platform dependent and as long as the code compiles it seems like it should work.

> Registers:
>  r0  = 0x000b0c00
>  r1  = 0x00006b70
>  r2  = 0x00000000
>  r3  = 0x00000064
>  r4  = 0x00000000
>  r5  = 0x000b0c00
>  r6  = 0x000b0c00
>  r7  = 0x00021400
>  r8  = 0x00020638
>  r9  = 0x4a650c58
>  r10 = 0x00000000
>  fp  = 0x406fcad4
>  r12 = 0x00000001
>  sp  = 0x406fca58
>  lr  = 0x403e1768
>  pc  = 0x40480278
> 
> 
> Register to memory mapping:
>  r0  = 0x000b0c00
> "Thread-2" prio=10 tid=0x000b0c00 nid=0x7da1 initialized [0x00000000]
>   java.lang.Thread.State: RUNNABLE

This is pretty verbose since we print the register values twice.  Why not just print them once by losing the first section?  The lack of indenting makes it less readable too though that's harder to fix without modifing every print_on routines which I'm not sure we want to do.  Maybe the printing should just start on the same line instead of having a cr in between.  Printing nothing for unknown values might make sense too.

tom

>  r1  = 0x00006b70
> 0x00006b70 is pointing to unknown location
>  r2  = 0x00000000
> 0x00000000 is pointing to unknown location
>  r3  = 0x00000064
> 0x00000064 is pointing to unknown location
>  r4  = 0x00000000
> 0x00000000 is pointing to unknown location
>  r5  = 0x000b0c00
> "Thread-2" prio=10 tid=0x000b0c00 nid=0x7da1 initialized [0x00000000]
>   java.lang.Thread.State: RUNNABLE
>  r6  = 0x000b0c00
> "Thread-2" prio=10 tid=0x000b0c00 nid=0x7da1 initialized [0x00000000]
>   java.lang.Thread.State: RUNNABLE
>  r7  = 0x00021400
> "main" prio=10 tid=0x00021400 nid=0x6d8d runnable [0x406fc000]
>   java.lang.Thread.State: RUNNABLE
>  r8  = 0x00020638
> 0x00020638 is pointing to unknown location
>  r9  = 0x4a650c58
> {method}
> - klass: {other class}
>  r10 = 0x00000000
> 0x00000000 is pointing to unknown location
>  fp  = 0x406fcad4
> 0x406fcad4 is pointing into the stack for thread: 0x00021400
> "main" prio=10 tid=0x00021400 nid=0x6d8d runnable [0x406fc000]
>   java.lang.Thread.State: RUNNABLE
>  r12 = 0x00000001
> 0x00000001 is pointing to unknown location
>  sp  = 0x406fca58
> 0x406fca58 is pointing into the stack for thread: 0x00021400
> "main" prio=10 tid=0x00021400 nid=0x6d8d runnable [0x406fc000]
>   java.lang.Thread.State: RUNNABLE
>  lr  = 0x403e1768
> 0x403e1768: JVM_StartThread+0xe8 in /java/embedded/users/dh198349/1.6.0_18/builds/b06/linux-armv5-eabi-sflt-full-dev/j2sdk-image/jre/lib/arm/client/libjvm.so at 0x40191000
>  pc  = 0x40480278
> 0x40480278: <offset 0x2ef278> in /java/embedded/users/dh198349/1.6.0_18/builds/b06/linux-armv5-eabi-sflt-full-dev/j2sdk-image/jre/lib/arm/client/libjvm.so at 0x40191000