79 lines
3.6 KiB
Diff
79 lines
3.6 KiB
Diff
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From 98940f219ba0e3eb6d958af483b73dd9cc75c28c Mon Sep 17 00:00:00 2001
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From: Mark Lam <mark.lam@apple.com>
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Date: Mon, 19 Dec 2022 17:32:15 -0800
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Subject: [PATCH] Cherry-pick 252432.839@safari-7614-branch (71cdc1c09ef1).
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rdar://102531234
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The provenType filtering in FTL's speculateRealNumber is incorrect.
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https://bugs.webkit.org/show_bug.cgi?id=248266
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<rdar://problem/102531234>
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Reviewed by Justin Michaud.
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speculateRealNumber does a doubleEqual compare, which filters out double values which
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are not NaN. NaN values will fall through to the `intCase` block. In the `intCase` block,
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the isNotInt32() check there was given a proven type that wrongly filters out ~SpecFullDouble.
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Consider a scenario where the edge was proven to be { SpecInt32Only, SpecDoubleReal,
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SpecDoublePureNaN }. SpecFullDouble is defined as SpecDoubleReal | SpecDoubleNaN, and
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SpecDoubleNaN is defined as SpecDoublePureNaN | SpecDoubleImpureNaN. Hence, the filtering
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of the proven type with ~SpecFullDouble means that isNotInt32() will effectively be given
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a proven type of
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{ SpecInt32Only, SpecDoubleReal, SpecDoublePureNaN } - { SpecDoubleReal, SpecDoublePureNaN }
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which yields
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{ SpecInt32Only }.
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As a result, the compiler will think that that isNotIn32() check will always fail. This
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is not correct if the actual incoming value for that edge is actually a PureNaN. In this
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case, speculateRealNumber should have OSR exited, but it doesn't because it thinks that
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the isNotInt32() check will always fail and elide the check altogether.
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In this patch, we fix this by replacing the ~SpecFullDouble with ~SpecDoubleReal. We also
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rename the `intCase` block to `intOrNaNCase` to document what it actually handles.
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* JSTests/stress/speculate-real-number-in-object-is.js: Added.
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(test.object_is_opt):
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(test):
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* Source/JavaScriptCore/ftl/FTLLowerDFGToB3.cpp:
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(JSC::FTL::DFG::LowerDFGToB3::compileCompareStrictEq):
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Canonical link: https://commits.webkit.org/252432.839@safari-7614-branch
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Canonical link: https://commits.webkit.org/258113@main
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---
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.../speculate-real-number-in-object-is.js | 22 +++++++++++++++++++
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Source/JavaScriptCore/ftl/FTLLowerDFGToB3.cpp | 8 +++----
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2 files changed, 26 insertions(+), 4 deletions(-)
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create mode 100644 JSTests/stress/speculate-real-number-in-object-is.js
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diff --git a/Source/JavaScriptCore/ftl/FTLLowerDFGToB3.cpp b/Source/JavaScriptCore/ftl/FTLLowerDFGToB3.cpp
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index 3ba2d21b8072..18d13f1941bb 100644
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--- a/Source/JavaScriptCore/ftl/FTLLowerDFGToB3.cpp
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+++ b/Source/JavaScriptCore/ftl/FTLLowerDFGToB3.cpp
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@@ -20574,18 +20574,18 @@ IGNORE_CLANG_WARNINGS_END
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LValue value = lowJSValue(edge, ManualOperandSpeculation);
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LValue doubleValue = unboxDouble(value);
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- LBasicBlock intCase = m_out.newBlock();
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+ LBasicBlock intOrNaNCase = m_out.newBlock();
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LBasicBlock continuation = m_out.newBlock();
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m_out.branch(
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m_out.doubleEqual(doubleValue, doubleValue),
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- usually(continuation), rarely(intCase));
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+ usually(continuation), rarely(intOrNaNCase));
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- LBasicBlock lastNext = m_out.appendTo(intCase, continuation);
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+ LBasicBlock lastNext = m_out.appendTo(intOrNaNCase, continuation);
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typeCheck(
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jsValueValue(value), m_node->child1(), SpecBytecodeRealNumber,
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- isNotInt32(value, provenType(m_node->child1()) & ~SpecFullDouble));
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+ isNotInt32(value, provenType(m_node->child1()) & ~SpecDoubleReal));
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m_out.jump(continuation);
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m_out.appendTo(continuation, lastNext);
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