Re: RFR: 8255150: Add utility methods to check long indexes and ranges [v2]
On Thu, 5 Nov 2020 23:59:43 GMT, Dean Long wrote: > C2 changes look good, except for new code block in > inline_preconditions_checkIndex could use a comment. Thanks for the review. I added a comment for this block and some other comments for the rest of this method. - PR: https://git.openjdk.java.net/jdk/pull/1003
Re: RFR: 8255150: Add utility methods to check long indexes and ranges [v2]
On Fri, 6 Nov 2020 04:25:40 GMT, Dean Long wrote:
>> src/hotspot/share/opto/library_call.cpp line 1015:
>>
>>> 1013: Deoptimization::Action_make_not_entrant);
>>> 1014: }
>>> 1015:
>>
>> A comment here explaining what the code below is doing would be helpful.
>
> This code wasn't here before, so I'm guessing it's needed for T_LONG. For
> T_INT is it just wasted work?
Code in IdealLoopTree::is_range_check_if() uses this check:
if (range->Opcode() != Op_LoadRange && !iff->is_RangeCheck()) {
const TypeInt* tint = phase->_igvn.type(range)->isa_int();
if (tint == NULL || tint->empty() || tint->_lo < 0) {
// Allow predication on positive values that aren't LoadRanges.
// This allows optimization of loops where the length of the
// array is a known value and doesn't need to be loaded back
// from the array.
return false;
that is it assumes that everything that's on the right hand size of the a
RangeCheck test is positive. I think it's cleaner and less dangerous to
explicitly cast the length to >= 0 when the intrinsic is built. In a subsequent
patch I intend to drop the && !iff->is_RangeCheck() check above.
-
PR: https://git.openjdk.java.net/jdk/pull/1003
Re: RFR: 8255150: Add utility methods to check long indexes and ranges [v2]
On Thu, 5 Nov 2020 23:58:21 GMT, Dean Long wrote: >> Roland Westrelin has updated the pull request with a new target base due to >> a merge or a rebase. The pull request now contains ten commits: >> >> - Jorn's comments >> - Update headers and add intrinsic to Graal test ignore list >> - move compiler test and add bug to test >> - non x86_64 arch support >> - c2 test case >> - intrinsic >> - Use overloads of method names. >> >>Simplify internally to avoid overload resolution >>issues, leverging List for the exception >>mapper. >> - Vladimir's comments >> - checkLongIndex > > src/hotspot/share/opto/library_call.cpp line 1015: > >> 1013: Deoptimization::Action_make_not_entrant); >> 1014: } >> 1015: > > A comment here explaining what the code below is doing would be helpful. This code wasn't here before, so I'm guessing it's needed for T_LONG. For T_INT is it just wasted work? - PR: https://git.openjdk.java.net/jdk/pull/1003
Re: RFR: 8255150: Add utility methods to check long indexes and ranges [v2]
On Thu, 5 Nov 2020 15:47:31 GMT, Roland Westrelin wrote: >> This change add 3 new methods in Objects: >> >> public static long checkIndex(long index, long length) >> public static long checkFromToIndex(long fromIndex, long toIndex, long >> length) >> public static long checkFromIndexSize(long fromIndex, long size, long length) >> >> This mirrors the int utility methods that were added by JDK-8135248 >> with the same motivations. >> >> As is the case with the int checkIndex(), the long checkIndex() method >> is JIT compiled as an intrinsic. It allows the JIT to compile >> checkIndex to an unsigned comparison and properly recognize it as >> a range check that then becomes a candidate for the existing range check >> optimizations. This has proven to be important for panama's >> MemorySegment API and a prototype of this change (with some extra c2 >> improvements) showed that panama micro benchmark results improve >> significantly. >> >> This change includes: >> >> - the API change >> - the C2 intrinsic >> - tests for the API and the C2 intrinsic >> >> This is a joint work with Paul who reviewed and reworked the API change >> and filled the CSR. > > Roland Westrelin has updated the pull request with a new target base due to a > merge or a rebase. The pull request now contains ten commits: > > - Jorn's comments > - Update headers and add intrinsic to Graal test ignore list > - move compiler test and add bug to test > - non x86_64 arch support > - c2 test case > - intrinsic > - Use overloads of method names. > >Simplify internally to avoid overload resolution >issues, leverging List for the exception >mapper. > - Vladimir's comments > - checkLongIndex C2 changes look good, except for new code block in inline_preconditions_checkIndex could use a comment. src/hotspot/share/opto/library_call.cpp line 1015: > 1013: Deoptimization::Action_make_not_entrant); > 1014: } > 1015: A comment here explaining what the code below is doing would be helpful. - Changes requested by dlong (Reviewer). PR: https://git.openjdk.java.net/jdk/pull/1003
Re: RFR: 8255150: Add utility methods to check long indexes and ranges [v2]
On Thu, 5 Nov 2020 15:42:54 GMT, Roland Westrelin wrote:
>> src/java.base/share/classes/java/lang/IndexOutOfBoundsException.java line 83:
>>
>>> 81: */
>>> 82: public IndexOutOfBoundsException(long index) {
>>> 83: super("Index out of range: " + index);
>>
>> For consistency with the class name:
>> Suggestion:
>>
>> super("Index out of bounds: " + index);
>
> Not sure about that one as it's a copy of the message from
> IndexOutOfBoundsException(int index). Both would need to be changed for
> consistency.
Ok, I didn't notice that it was taken from elsewhere. Never mind then.
-
PR: https://git.openjdk.java.net/jdk/pull/1003
Re: RFR: 8255150: Add utility methods to check long indexes and ranges [v2]
> This change add 3 new methods in Objects: > > public static long checkIndex(long index, long length) > public static long checkFromToIndex(long fromIndex, long toIndex, long length) > public static long checkFromIndexSize(long fromIndex, long size, long length) > > This mirrors the int utility methods that were added by JDK-8135248 > with the same motivations. > > As is the case with the int checkIndex(), the long checkIndex() method > is JIT compiled as an intrinsic. It allows the JIT to compile > checkIndex to an unsigned comparison and properly recognize it as > a range check that then becomes a candidate for the existing range check > optimizations. This has proven to be important for panama's > MemorySegment API and a prototype of this change (with some extra c2 > improvements) showed that panama micro benchmark results improve > significantly. > > This change includes: > > - the API change > - the C2 intrinsic > - tests for the API and the C2 intrinsic > > This is a joint work with Paul who reviewed and reworked the API change > and filled the CSR. Roland Westrelin has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains ten additional commits since the last revision: - Jorn's comments - Update headers and add intrinsic to Graal test ignore list - move compiler test and add bug to test - non x86_64 arch support - c2 test case - intrinsic - Use overloads of method names. Simplify internally to avoid overload resolution issues, leverging List for the exception mapper. - Vladimir's comments - checkLongIndex - Changes: - all: https://git.openjdk.java.net/jdk/pull/1003/files - new: https://git.openjdk.java.net/jdk/pull/1003/files/74df12d3..b47184ac Webrevs: - full: https://webrevs.openjdk.java.net/?repo=jdk=1003=01 - incr: https://webrevs.openjdk.java.net/?repo=jdk=1003=00-01 Stats: 11784 lines in 698 files changed: 6370 ins; 3584 del; 1830 mod Patch: https://git.openjdk.java.net/jdk/pull/1003.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/1003/head:pull/1003 PR: https://git.openjdk.java.net/jdk/pull/1003
Re: RFR: 8255150: Add utility methods to check long indexes and ranges [v2]
On Thu, 5 Nov 2020 11:58:43 GMT, Jorn Vernee wrote:
> Although I'm not a 'Reviewer', I've done a pass over the code and left some
> inline comments that I hope you find useful.
Thanks for the review! All suggestions (except the exception message one that I
commented on) look good to me. I applied them.
> src/java.base/share/classes/java/lang/IndexOutOfBoundsException.java line 83:
>
>> 81: */
>> 82: public IndexOutOfBoundsException(long index) {
>> 83: super("Index out of range: " + index);
>
> For consistency with the class name:
> Suggestion:
>
> super("Index out of bounds: " + index);
Not sure about that one as it's a copy of the message from
IndexOutOfBoundsException(int index). Both would need to be changed for
consistency.
-
PR: https://git.openjdk.java.net/jdk/pull/1003
