Changeset 265074 in webkit for trunk/Source/JavaScriptCore/b3/B3ValueKey.cpp

Timestamp:

Jul 29, 2020, 9:42:46 PM (5 years ago)

Author:

[email protected]

Message:

[JSC] Add B3::BottomTupleValue node
​https://bugs.webkit.org/show_bug.cgi?id=214956
<rdar://problem/65192877>

Reviewed by Keith Miller.

JSTests:

• wasm/stress/bottom-tuple.js: Added.

(try.main):
(catch):

Source/JavaScriptCore:

In B3 strength reduction, we convert B3 values to bottom value based on type after Oops kind, and then they are *typically* removed later.
While we support bottom values for usual types, we do not have a bottom value for tuple type. So when replaceWithBottom is called, we
fail to replace Patchpoints producing tuples with bottom values.

This patch newly adds B3 BottomTupleValue, which is just a BottomValue for tuple. We can extend it to generate arbitrary constant
tuple values, but for now, we just support bottom tuple values. We add a new node instead of generating patchpoint which generates bottom
values since BottomTupleValues implementation is simpler: BottomTupleValue just emits bunch of zero clear for Air tmps and Air does everything
automatically. On the other hand, implementing a patchpoint needs to add code which clears things with zero while checking the ValueRep. And
since we have Const32, Const64, etc. values, having this kind of value for tuple too is natural. Plus, this design allows us to remove bunch
of unnecessary instructions after lowering this to Air since Air knows what instructions will be emitted by this BottomTupleValue, and Air
can remove a lot of zero clear instructions if they are not read later by Extract.

• JavaScriptCore.xcodeproj/project.pbxproj:
• Sources.txt:
• b3/B3BottomTupleValue.cpp: Copied from Source/JavaScriptCore/b3/B3InsertionSet.cpp.

(JSC::B3::BottomTupleValue::dumpMeta const):

• b3/B3BottomTupleValue.h: Copied from Source/JavaScriptCore/b3/B3InsertionSet.cpp.
• b3/B3InsertionSet.cpp:

(JSC::B3::InsertionSet::insertBottom):

• b3/B3LowerToAir.cpp:
• b3/B3Opcode.cpp:

(WTF::printInternal):

• b3/B3Opcode.h:
• b3/B3Procedure.cpp:

(JSC::B3::Procedure::addBottom):

• b3/B3TypeMap.h:

(JSC::B3::TypeMap::TypeMap): Deleted.

• b3/B3Validate.cpp:
• b3/B3Value.cpp:

(JSC::B3::Value::effects const):
(JSC::B3::Value::key const):

• b3/B3Value.h:
• b3/B3ValueInlines.h:
• b3/B3ValueKey.cpp:

(JSC::B3::ValueKey::materialize const):

• b3/testb3_7.cpp:

(testBottomTupleValue):
(addTupleTests):

File:

• trunk/Source/JavaScriptCore/b3/B3ValueKey.cpp (modified) (1 diff)

trunk/Source/JavaScriptCore/b3/B3ValueKey.cpp

@@ -117 +117 @@
     case ConstFloat:
         return proc.add<ConstFloatValue>(origin, floatValue());
+    case BottomTuple:
+        return proc.add<BottomTupleValue>(origin, type());
     case ArgumentReg:
         return proc.add<ArgumentRegValue>(origin, Reg::fromIndex(static_cast<unsigned>(value())));