[JSC] Simplify resolve_scope for ClosureVar

https://bugs.webkit.org/show_bug.cgi?id=275671 rdar://130166983 Reviewed by Justin Michaud. Due to profiled result, we already know local scope depth at this point. Emit sequence of load instead of loop for smaller local scope depth. * Source/JavaScriptCore/jit/JITPropertyAccess.cpp: (JSC::JIT::emit_op_resolve_scope): Canonical link: https://commits.webkit.org/280191@main
WebKit · Jun 20, 2024 · 2cf423a · 2cf423a
1 parent 2e6697f
commit 2cf423a
Showing 1 changed file with 11 additions and 6 deletions.
diff --git a/Source/JavaScriptCore/jit/JITPropertyAccess.cpp b/Source/JavaScriptCore/jit/JITPropertyAccess.cpp
@@ -946,13 +946,18 @@ void JIT::emit_op_resolve_scope(const JSInstruction* currentInstruction)
  else {
  emitGetVirtualRegisterPayload(scope, scopeGPR);
  if (profiledResolveType == ClosureVar) {
- load32FromMetadata(bytecode, OpResolveScope::Metadata::offsetOfLocalScopeDepth(), scratch1GPR);
  static_assert(scopeGPR == returnValueGPR);
- Jump done = branchTest32(Zero, scratch1GPR);
- auto loop = label();
- loadPtr(Address(returnValueGPR, JSScope::offsetOfNext()), returnValueGPR);
- branchSub32(NonZero, scratch1GPR, TrustedImm32(1), scratch1GPR).linkTo(loop, this);
- done.link(this);
+ unsigned localScopeDepth = bytecode.metadata(m_profiledCodeBlock).m_localScopeDepth;
+ if (localScopeDepth < 8) {
+ for (unsigned index = 0; index < localScopeDepth; ++index)
+ loadPtr(Address(returnValueGPR, JSScope::offsetOfNext()), returnValueGPR);
+ } else {
+ ASSERT(localScopeDepth >= 8);
+ load32FromMetadata(bytecode, OpResolveScope::Metadata::offsetOfLocalScopeDepth(), scratch1GPR);
+ auto loop = label();
+ loadPtr(Address(returnValueGPR, JSScope::offsetOfNext()), returnValueGPR);
+ branchSub32(NonZero, scratch1GPR, TrustedImm32(1), scratch1GPR).linkTo(loop, this);
+ }
  } else {
  uint32_t metadataOffset = m_profiledCodeBlock->metadataTable()->offsetInMetadataTable(bytecode);
  addPtr(TrustedImm32(metadataOffset), s_metadataGPR, metadataGPR);