Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: 93a4fbeda18317d134d83ccabc3abc7abc2ae12f
      
https://github.com/WebKit/WebKit/commit/93a4fbeda18317d134d83ccabc3abc7abc2ae12f
  Author: Sosuke Suzuki <[email protected]>
  Date:   2026-05-21 (Thu, 21 May 2026)

  Changed paths:
    A JSTests/microbenchmarks/string-from-code-point.js
    A JSTests/stress/string-from-code-point-intrinsic.js
    M Source/JavaScriptCore/dfg/DFGAbstractInterpreterInlines.h
    M Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp
    M Source/JavaScriptCore/dfg/DFGClobberize.h
    M Source/JavaScriptCore/dfg/DFGCloneHelper.h
    M Source/JavaScriptCore/dfg/DFGDoesGC.cpp
    M Source/JavaScriptCore/dfg/DFGFixupPhase.cpp
    M Source/JavaScriptCore/dfg/DFGLoopUnrollingPhase.cpp
    M Source/JavaScriptCore/dfg/DFGNodeType.h
    M Source/JavaScriptCore/dfg/DFGOperations.cpp
    M Source/JavaScriptCore/dfg/DFGOperations.h
    M Source/JavaScriptCore/dfg/DFGPredictionPropagationPhase.cpp
    M Source/JavaScriptCore/dfg/DFGSafeToExecute.h
    M Source/JavaScriptCore/dfg/DFGSpeculativeJIT.cpp
    M Source/JavaScriptCore/dfg/DFGSpeculativeJIT.h
    M Source/JavaScriptCore/dfg/DFGSpeculativeJIT32_64.cpp
    M Source/JavaScriptCore/dfg/DFGSpeculativeJIT64.cpp
    M Source/JavaScriptCore/dfg/DFGValidate.cpp
    M Source/JavaScriptCore/ftl/FTLCapabilities.cpp
    M Source/JavaScriptCore/ftl/FTLLowerDFGToB3.cpp
    M Source/JavaScriptCore/jit/ThunkGenerators.cpp
    M Source/JavaScriptCore/jit/ThunkGenerators.h
    M Source/JavaScriptCore/runtime/Intrinsic.h
    M Source/JavaScriptCore/runtime/StringConstructor.cpp
    M Source/JavaScriptCore/runtime/StringConstructor.h
    M Source/JavaScriptCore/runtime/VM.cpp

  Log Message:
  -----------
  [JSC] Add DFG node for `String.fromCodePoint`
https://bugs.webkit.org/show_bug.cgi?id=315201

Reviewed by Yusuke Suzuki.

This patch adds a new StringFromCodePoint DFG node and
FromCodePointIntrinsic for String.fromCodePoint().

When the argument is an Int32 in [0, 0xFF], the result is identical to
StringFromCharCode, so the DFG/FTL fast path is shared with it
(compileStringFromCharCodeOrCodePoint): an inline lookup of the
small-string table, falling back to a runtime call for larger code
points, surrogate pairs, and the out-of-range RangeError.

Unlike StringFromCharCode, this can throw a RangeError even for an Int32
argument, so NodeMustGenerate is never cleared in fixup, and clobberize
models it as write(SideState).

                                TipOfTree                  Patched

string-from-code-point       97.3232+-1.5882     ^     18.6356+-0.2575        ^ 
definitely 5.2224x faster

* JSTests/microbenchmarks/string-from-code-point.js: Added.
(fromCodePointLatin1):
(fromCodePointBMP):
(fromCodePointMixed):
* JSTests/stress/string-from-code-point-intrinsic.js: Added.
(shouldBe):
(fromCodePointBMP):
(fromCodePointSupplementary):
(fromCodePointMaybeThrows):
(fromCodePointDouble):
(fromCodePointObject):
(const.obj.valueOf):
(fromCodePointMulti):
(fromCodePointDead):
* Source/JavaScriptCore/dfg/DFGAbstractInterpreterInlines.h:
(JSC::DFG::AbstractInterpreter<AbstractStateType>::executeEffects):
* Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp:
(JSC::DFG::ByteCodeParser::handleIntrinsicCall):
* Source/JavaScriptCore/dfg/DFGClobberize.h:
(JSC::DFG::clobberize):
* Source/JavaScriptCore/dfg/DFGCloneHelper.h:
* Source/JavaScriptCore/dfg/DFGDoesGC.cpp:
(JSC::DFG::doesGC):
* Source/JavaScriptCore/dfg/DFGFixupPhase.cpp:
(JSC::DFG::FixupPhase::fixupNode):
* Source/JavaScriptCore/dfg/DFGLoopUnrollingPhase.cpp:
(JSC::DFG::LoopUnrollingPhase::isLoopBodyUnrollable):
* Source/JavaScriptCore/dfg/DFGNodeType.h:
* Source/JavaScriptCore/dfg/DFGOperations.cpp:
(JSC::DFG::JSC_DEFINE_JIT_OPERATION):
* Source/JavaScriptCore/dfg/DFGOperations.h:
* Source/JavaScriptCore/dfg/DFGPredictionPropagationPhase.cpp:
* Source/JavaScriptCore/dfg/DFGSafeToExecute.h:
(JSC::DFG::safeToExecute):
* Source/JavaScriptCore/dfg/DFGSpeculativeJIT.cpp:
(JSC::DFG::SpeculativeJIT::compileStringFromCharCodeOrCodePoint):
(JSC::DFG::SpeculativeJIT::compileFromCharCode): Deleted.
* Source/JavaScriptCore/dfg/DFGSpeculativeJIT.h:
* Source/JavaScriptCore/dfg/DFGSpeculativeJIT32_64.cpp:
(JSC::DFG::SpeculativeJIT::compile):
* Source/JavaScriptCore/dfg/DFGSpeculativeJIT64.cpp:
(JSC::DFG::SpeculativeJIT::compile):
* Source/JavaScriptCore/dfg/DFGValidate.cpp:
* Source/JavaScriptCore/ftl/FTLCapabilities.cpp:
(JSC::FTL::canCompile):
* Source/JavaScriptCore/ftl/FTLLowerDFGToB3.cpp:
(JSC::FTL::DFG::LowerDFGToB3::compileNode):
(JSC::FTL::DFG::LowerDFGToB3::compileStringFromCharCodeOrCodePoint):
(JSC::FTL::DFG::LowerDFGToB3::compileStringFromCharCode): Deleted.
* Source/JavaScriptCore/jit/ThunkGenerators.cpp:
(JSC::fromCodePointThunkGenerator):
* Source/JavaScriptCore/jit/ThunkGenerators.h:
* Source/JavaScriptCore/runtime/Intrinsic.h:
* Source/JavaScriptCore/runtime/StringConstructor.cpp:
(JSC::stringFromCodePoint):
* Source/JavaScriptCore/runtime/StringConstructor.h:
* Source/JavaScriptCore/runtime/VM.cpp:
(JSC::thunkGeneratorForIntrinsic):

Canonical link: https://commits.webkit.org/313696@main



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