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

Tobias Hartmann tobias.hartmann at oracle.com
Fri Jun 6 14:28:06 UTC 2014

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 

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


>> 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

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