[LWorld] Value type array support for C2 (and lots of bug fixes) (original) (raw)

Tobias Hartmann tobias.hartmann at oracle.com
Thu May 17 09:46:50 UTC 2018

Thanks for looking at this!

Best regards, Tobias

On 17.05.2018 11:30, David Simms wrote:

Looks good, thanks for correcting to use "ValueArrayFlatten" switch /D On 16/05/18 14:27, Tobias Hartmann wrote: Hi,

I've implemented value type array support for C2: http://cr.openjdk.java.net/~thartmann/valhalla/lworldarrays/webrev.00/ All compiler and runtime tests now pass! Here are the gory details: - Interpreter should only test for flattened arrays if ValueArrayFlatten is enabled (see templateTablex86.cpp) - Method handle inlining was broken with "signatures mismatch" because ciMethod::isconsistentinfo() returned false for value type arguments (see ciMethod.cpp) - Type flow analysis needs to support meeting value type arrays with other arrays (see ciTypeFlow.cpp) - Disabled C2 intrinsics that don't support value types as Ls yet (vmSymbols.cpp) - Alias analysis should retrieve field information when accessing flattened value type array element (see compile.cpp) - Method handle calls with value arguments are broken (didn't show up before because inlining was broken as well, see doCall.cpp) - Escape analysis should use flattened array offset to retrieve correct field type information for flattened value type array accesses (escape.cpp) - Implemented runtime checks for (flattened) value type array variants (graphKit.cpp) - Fixed returning null value type (parse1.cpp) - Added support for aaload/aastore on object or interface array with value type element. Added corresponding runtime tests. (parse2.cpp, parseHelper.cpp) - Changed type system to support (flattened) value type meet with other types (type.cpp) - Fixed removal of default value type allocations that may cause stray initializing stores to remain in the final code and re-initialize the default allocation (valuetypenode.cpp) - Disable ValueArrayFlatten if EnableValhalla is false (arguments.cpp) - Added lots of tests and re-enabled -Xcomp in ValueTypeArray.java - Some minor refactoring and comment fixes Open issues: - The uncommented part of ValueTypeArray.java needs to be fixed (I've filed JDK-8203291) - The currently disabled C2 intrinsics need to be implemented to support lworld - Avoid deoptimization if Object[] turns out to be value type array (use runtime calls) and improve runtime checks - Fix asymmetric type system [1] and check if we can get rid of TypeValueTypePtr (use TypeInstPtr) If there are no objections, I would like to push this large change and address the open issues in smaller follow-up patches. Thanks, Tobias

[1] Meeting TypeValueType with other types is currently not symmetric: === Meet Not Symmetric === t   =                   valuetype[3]:{int, byte, compiler/valhalla/valuetypes/MyValue2Inline} this=                   valuetype[8]:{long, int, int, short, java/lang/Integer, [I, compiler/valhalla/valuetypes/MyValue2, compiler/valhalla/valuetypes/MyValue2} mt=(t meet this)=       java/lang/Object:NotNull * tdual=                 valuetype[3]:{int, byte, compiler/valhalla/valuetypes/MyValue2Inline} thisdual=              valuetype[8]:{long, int, int, short, java/lang/Integer, [I, compiler/valhalla/valuetypes/MyValue2, compiler/valhalla/valuetypes/MyValue2} mtdual=                java/lang/Object:AnyNull *,iid=top (inlinedepth=InlineDepthTop) mtdual meet tdual=    java/lang/Object:AnyNull * mtdual meet thisdual= java/lang/Object:AnyNull * V  [libjvm.so+0x18eb1a1]  Type::meethelper(Type const*, bool) const+0x2b1 V  [libjvm.so+0x18ed113]  TypeAry::xmeet(Type const*) const+0xf3 V  [libjvm.so+0x18eaf34]  Type::meethelper(Type const*, bool) const+0x44 V  [libjvm.so+0x18f53d0]  TypeAryPtr::xmeethelper(Type const*) const+0xf0 V  [libjvm.so+0x18e1a96]  TypePtr::xmeet(Type const*) const+0x16 V  [libjvm.so+0x18eaf34]  Type::meethelper(Type const*, bool) const+0x44 V  [libjvm.so+0x911fc4]  ConstraintCastNode::dominatingcast(PhaseGVN*, PhaseTransform*) const+0x364 V  [libjvm.so+0x912a28]  CheckCastPPNode::Identity(PhaseGVN*)+0x38 V  [libjvm.so+0x16754b9]  PhaseGVN::transformnoreclaim(Node*)+0x189 V  [libjvm.so+0xea0bea]  GraphKit::gencheckcast(Node*, Node*, Node**)+0x2ea

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