[9] RFR: 8044538: assert(which != imm_operand) failed: instruction is not a movq reg, imm64

[Tobias Hartmann]

Hi Chris,

>> Hi Vladimir,
>>
>> thanks for the review.
>>
>>> Looks good. PrintRelocations flag is used very rare, that is why it rotted. Please, add jreg test (use -XX:+IgnoreUnrecognizedVMOptions).
>> I added a jtreg test to test/compiler/8044538/ that uses -Xcomp and -XX:+PrintRecolations. It fails without my changes.
> We are trying to not use bug id directories anymore.  Please move the test to a more meaningful directory with a meaningful name.

Okay, makes sense. I moved the test to 
test/compiler/PrintRelocations/TestPrintRelocations.java

New webrev: http://cr.openjdk.java.net/~thartmann/8044538/webrev.02/

Thanks,
Tobias

>> New webrev: http://cr.openjdk.java.net/~thartmann/8044538/webrev.01/
>>
>>> Since this debug flag almost never used backporting the fix only into 8u may be enough.
>> Okay.
>>
>> Thanks,
>> Tobias
>>
>>> Thanks,
>>> Vladimir
>>>
>>> On 6/4/14 1:30 AM, Tobias Hartmann wrote:
>>>> Hi,
>>>>
>>>> please review the following patch for bug 8044538.
>>>>
>>>> *Problem*
>>>> Executing a debug build of HotSpot with the flags -XX:+PrintRelocations
>>>> -Xcomp hits a ShouldNotReachHere() or an assert in
>>>> Assembler::locate_operand(..) stating that the instruction for which we
>>>> try to find the operand is not valid.
>>>>
>>>> The problem occurs while printing the relocation entries for a C2
>>>> compiled function. The C2 compiler adds internal_word_type relocations
>>>> for the jump table entries in the constant section of a method (see
>>>> Compile::ConstantTable::fill_jump_table(...)). These relocations are
>>>> processed by RelocIterator::print_current(...) and
>>>> internal_word_Relocation::target().
>>>> Relocation::pd_get_address_from_code() then tries to retrieve the
>>>> address from an instruction but fails because the relocation points into
>>>> the constant section only containing the target address.
>>>>
>>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8044538
>>>>
>>>> *Solution*
>>>> The implementation of internal_word_Relocation::target() is changed to
>>>> check if the relocation points into the constant section and if so
>>>> directly returns the target address instead of trying to retrieve it
>>>> from an instruction. The same is already done in
>>>> internal_word_Relocation::fix_relocation_after_move(..).
>>>>
>>>> Webrev: http://cr.openjdk.java.net/~thartmann/8044538/webrev.00/
>>>>
>>>> *Tests*
>>>> Failing configuration, JPRT
>>>>
>>>> Apparently this did not show up for any of our tests. Do we need an
>>>> additional test for this?
>>>> Since it already fails for JDK 7 and 8. Should we backport the patch?
>>>>
>>>> Thanks,
>>>> Tobias
>>>>
>>>>