Changeset 171096 in webkit for trunk/Source/JavaScriptCore/dfg/DFGStrengthReductionPhase.cpp

Timestamp:

Jul 14, 2014, 5:41:39 PM (11 years ago)

Author:

[email protected]

Message:

Allow for Int52Rep to see things other than Int32, and make this testable
​https://bugs.webkit.org/show_bug.cgi?id=134873
<rdar://problem/17641915>

Reviewed by Geoffrey Garen and Mark Hahnenberg.

A major premise of our type inference is that prediction propagation can say whatever it
wants and we'll still have valid IR after Fixup. This previously didn't work with Int52s.
We required some kind of agreement between prediction propagation and fixup over which
data flow paths were Int52 and which weren't.

It turns out that we basically had such an agreement, with the exception of code that was
unreachable due to ForceOSRExit. Then, fixup and prediction propagation would disagree. It
might be nice to fix that bug - but it's only in the case of Int52 that such a thing would
be a bug! Normally, we allow sloppiness in prediction propagation.

This patch allows us to be sloppy with Int52 prediction propagation by giving Int52Rep the
ability to see inputs other than Int32. This fixes the particular ForceOSRExit bug (see
int52-force-osr-exit-path.js for the reduced test case). To make sure that the newly
empowered Int52Rep is actually correct - in case we end up using it on paths other than
ForceOSRExit - this patch introduces an internal intrinsic called fiatInt52() that forces
us to attempt Int52 conversion on the input. This patch adds a bunch of tests that stress
this intrinsic. This means that we're now stressing Int52Rep more so than ever before!

Note that it would still be a bug for prediction propagation to ever cause us to create an
Int52Rep node for a non-Int32 input. But, this will now be a performance bug, rather than
a crash bug.

• dfg/DFGAbstractInterpreterInlines.h:

(JSC::DFG::AbstractInterpreter<AbstractStateType>::executeEffects):

• dfg/DFGAbstractValue.cpp:

(JSC::DFG::AbstractValue::fixTypeForRepresentation):

• dfg/DFGByteCodeParser.cpp:

(JSC::DFG::ByteCodeParser::handleIntrinsic):

• dfg/DFGClobberize.h:

(JSC::DFG::clobberize):

• dfg/DFGFixupPhase.cpp:

(JSC::DFG::FixupPhase::fixupNode):
(JSC::DFG::FixupPhase::injectTypeConversionsForEdge):

• dfg/DFGGraph.h:

(JSC::DFG::Graph::isMachineIntConstant):

• dfg/DFGNode.h:

(JSC::DFG::Node::isMachineIntConstant):

• dfg/DFGNodeType.h:
• dfg/DFGOperations.cpp:
• dfg/DFGOperations.h:
• dfg/DFGPredictionPropagationPhase.cpp:

(JSC::DFG::PredictionPropagationPhase::propagate):

• dfg/DFGSafeToExecute.h:

(JSC::DFG::SafeToExecuteEdge::operator()):
(JSC::DFG::safeToExecute):

• dfg/DFGSpeculativeJIT.cpp:

(JSC::DFG::SpeculativeJIT::speculate):

• dfg/DFGSpeculativeJIT.h:

(JSC::DFG::SpeculativeJIT::callOperation):

• dfg/DFGSpeculativeJIT32_64.cpp:

(JSC::DFG::SpeculativeJIT::compile):

• dfg/DFGSpeculativeJIT64.cpp:

(JSC::DFG::SpeculativeJIT::compile):
(JSC::DFG::SpeculativeJIT::convertMachineInt):
(JSC::DFG::SpeculativeJIT::speculateMachineInt):
(JSC::DFG::SpeculativeJIT::speculateDoubleRepMachineInt):

• dfg/DFGStrengthReductionPhase.cpp:

(JSC::DFG::StrengthReductionPhase::handleNode):

• dfg/DFGUseKind.cpp:

(WTF::printInternal):

• dfg/DFGUseKind.h:

(JSC::DFG::typeFilterFor):
(JSC::DFG::isNumerical):
(JSC::DFG::isDouble):

• dfg/DFGValidate.cpp:

(JSC::DFG::Validate::validate):

• ftl/FTLCapabilities.cpp:

(JSC::FTL::canCompile):

• ftl/FTLIntrinsicRepository.h:
• ftl/FTLLowerDFGToLLVM.cpp:

(JSC::FTL::LowerDFGToLLVM::compileInt52Rep):
(JSC::FTL::LowerDFGToLLVM::doubleToInt32):
(JSC::FTL::LowerDFGToLLVM::jsValueToDouble):
(JSC::FTL::LowerDFGToLLVM::jsValueToStrictInt52):
(JSC::FTL::LowerDFGToLLVM::doubleToStrictInt52):
(JSC::FTL::LowerDFGToLLVM::speculate):
(JSC::FTL::LowerDFGToLLVM::speculateMachineInt):
(JSC::FTL::LowerDFGToLLVM::speculateDoubleRepMachineInt):

• jit/JITOperations.h:
• jsc.cpp:

(GlobalObject::finishCreation):
(functionIdentity):

• runtime/Intrinsic.h:
• runtime/JSCJSValue.h:
• runtime/JSCJSValueInlines.h:

(JSC::tryConvertToInt52):
(JSC::isInt52):
(JSC::JSValue::isMachineInt):

• tests/stress/dead-fiat-double-to-int52-then-exit-not-int52.js: Added.

(foo):

• tests/stress/dead-fiat-double-to-int52.js: Added.

(foo):

• tests/stress/dead-fiat-int32-to-int52.js: Added.

(foo):

• tests/stress/dead-fiat-value-to-int52-double-path.js: Added.

(foo):
(bar):

• tests/stress/dead-fiat-value-to-int52-then-exit-not-double.js: Added.

(foo):
(bar):

• tests/stress/dead-fiat-value-to-int52-then-exit-not-int52.js: Added.

(foo):
(bar):

• tests/stress/dead-fiat-value-to-int52.js: Added.

(foo):
(bar):

• tests/stress/fiat-double-to-int52-then-exit-not-int52.js: Added.

(foo):

• tests/stress/fiat-double-to-int52-then-fail-to-fold.js: Added.

(foo):

• tests/stress/fiat-double-to-int52-then-fold.js: Added.

(foo):

• tests/stress/fiat-double-to-int52.js: Added.

(foo):

• tests/stress/fiat-int32-to-int52.js: Added.

(foo):

• tests/stress/fiat-value-to-int52-double-path.js: Added.

(foo):
(bar):

• tests/stress/fiat-value-to-int52-then-exit-not-double.js: Added.

(foo):
(bar):

• tests/stress/fiat-value-to-int52-then-exit-not-int52.js: Added.

(foo):
(bar):

• tests/stress/fiat-value-to-int52-then-fail-to-fold.js: Added.

(foo):

• tests/stress/fiat-value-to-int52-then-fold.js: Added.

(foo):

• tests/stress/fiat-value-to-int52.js: Added.

(foo):
(bar):

• tests/stress/int52-force-osr-exit-path.js: Added.

(foo):

File:

• trunk/Source/JavaScriptCore/dfg/DFGStrengthReductionPhase.cpp (modified) (2 diffs)

trunk/Source/JavaScriptCore/dfg/DFGStrengthReductionPhase.cpp

@@ -185 +185 @@
             bool hadInt32Check = false;
             if (m_node->op() == Int52Rep) {
-                ASSERT(m_node->child1().useKind() == Int32Use);
+                if (m_node->child1().useKind() != Int32Use)
+                    break;
                 hadInt32Check = true;
             }
@@ -212 +213 @@
                 switch (node->op()) {
                 case Int52Rep:
-                    ASSERT(node->child1().useKind() == Int32Use);
+                    if (node->child1().useKind() != Int32Use)
+                        break;
                     hadInt32Check = true;
                     continue;