diff --git a/Source/JavaScriptCore/ChangeLog b/Source/JavaScriptCore/ChangeLog
index 90be12c..b8866e0 100644
--- a/Source/JavaScriptCore/ChangeLog
+++ b/Source/JavaScriptCore/ChangeLog
@@ -1,5 +1,145 @@
 2020-01-16  Robin Morisset  <rmorisset@apple.com>
 
+        Use dataLogIf more regularly
+        https://bugs.webkit.org/show_bug.cgi?id=206332
+
+        Reviewed by Keith Miller.
+
+        There is lots of code that reads
+          if (Options::foobar())
+            dataLogLn("...")
+
+        There are a couple of benefits to replacing those by dataLogLnIf(Options::foobar(), "..."):
+        - Readability, by reducing the number of lines taken by logging
+        - Less lines appearing as not-taken in test coverage wrongly (wrongly because we probably don't care for the coverage of logging code)
+        - possibly a tiny perf benefit since dataLogIf correctly uses UNLIKELY.
+
+        This patch is a fairly trivial refactoring where I looked for that pattern and replaced it everywhere it appeared in JSC.
+
+        * bytecode/BytecodeGeneratorification.cpp:
+        (JSC::performGeneratorification):
+        * bytecode/BytecodeLivenessAnalysis.cpp:
+        (JSC::BytecodeLivenessAnalysis::BytecodeLivenessAnalysis):
+        * bytecode/CallLinkInfo.cpp:
+        (JSC::CallLinkInfo::visitWeak):
+        * bytecode/CodeBlock.cpp:
+        (JSC::CodeBlock::finalizeLLIntInlineCaches):
+        (JSC::CodeBlock::noticeIncomingCall):
+        (JSC::CodeBlock::optimizationThresholdScalingFactor):
+        (JSC::CodeBlock::optimizeNextInvocation):
+        (JSC::CodeBlock::dontOptimizeAnytimeSoon):
+        (JSC::CodeBlock::optimizeAfterWarmUp):
+        (JSC::CodeBlock::optimizeAfterLongWarmUp):
+        (JSC::CodeBlock::optimizeSoon):
+        (JSC::CodeBlock::forceOptimizationSlowPathConcurrently):
+        (JSC::CodeBlock::setOptimizationThresholdBasedOnCompilationResult):
+        (JSC::CodeBlock::shouldOptimizeNow):
+        * bytecode/DFGExitProfile.cpp:
+        (JSC::DFG::ExitProfile::add):
+        * dfg/DFGByteCodeParser.cpp:
+        (JSC::DFG::ByteCodeParser::parseCodeBlock):
+        * dfg/DFGCFAPhase.cpp:
+        * dfg/DFGJITCode.cpp:
+        (JSC::DFG::JITCode::optimizeNextInvocation):
+        (JSC::DFG::JITCode::dontOptimizeAnytimeSoon):
+        (JSC::DFG::JITCode::optimizeAfterWarmUp):
+        (JSC::DFG::JITCode::optimizeSoon):
+        (JSC::DFG::JITCode::forceOptimizationSlowPathConcurrently):
+        (JSC::DFG::JITCode::setOSREntryBlock):
+        * dfg/DFGJumpReplacement.cpp:
+        (JSC::DFG::JumpReplacement::fire):
+        * dfg/DFGOSREntry.cpp:
+        (JSC::DFG::prepareOSREntry):
+        * dfg/DFGOSRExit.cpp:
+        (JSC::DFG::OSRExit::compileExit):
+        * dfg/DFGObjectAllocationSinkingPhase.cpp:
+        * dfg/DFGOperations.cpp:
+        * dfg/DFGPlan.cpp:
+        (JSC::DFG::Plan::compileInThreadImpl):
+        * dfg/DFGToFTLDeferredCompilationCallback.cpp:
+        (JSC::DFG::ToFTLDeferredCompilationCallback::compilationDidBecomeReadyAsynchronously):
+        (JSC::DFG::ToFTLDeferredCompilationCallback::compilationDidComplete):
+        * dfg/DFGToFTLForOSREntryDeferredCompilationCallback.cpp:
+        (JSC::DFG::ToFTLForOSREntryDeferredCompilationCallback::compilationDidBecomeReadyAsynchronously):
+        (JSC::DFG::ToFTLForOSREntryDeferredCompilationCallback::compilationDidComplete):
+        * dfg/DFGWorklist.cpp:
+        (JSC::DFG::Worklist::completeAllReadyPlansForVM):
+        * ftl/FTLOSREntry.cpp:
+        (JSC::FTL::prepareOSREntry):
+        * heap/Heap.cpp:
+        (JSC::Heap::lastChanceToFinalize):
+        (JSC::Heap::sweepSynchronously):
+        (JSC::Heap::collectNow):
+        (JSC::Heap::runBeginPhase):
+        (JSC::Heap::runFixpointPhase):
+        (JSC::Heap::runReloopPhase):
+        (JSC::Heap::runEndPhase):
+        (JSC::Heap::finalize):
+        (JSC::Heap::willStartCollection):
+        (JSC::Heap::updateAllocationLimits):
+        (JSC::Heap::notifyIsSafeToCollect):
+        * heap/MarkStackMergingConstraint.cpp:
+        (JSC::MarkStackMergingConstraint::prepareToExecuteImpl):
+        * heap/MarkedSpace.cpp:
+        * heap/MarkingConstraint.cpp:
+        (JSC::MarkingConstraint::prepareToExecute):
+        * heap/MarkingConstraintSet.cpp:
+        (JSC::MarkingConstraintSet::executeConvergence):
+        (JSC::MarkingConstraintSet::executeConvergenceImpl):
+        (JSC::MarkingConstraintSet::executeAll):
+        * heap/MarkingConstraintSolver.cpp:
+        (JSC::MarkingConstraintSolver::execute):
+        * heap/SlotVisitor.cpp:
+        (JSC::SlotVisitor::appendToMarkStack):
+        (JSC::SlotVisitor::visitChildren):
+        (JSC::SlotVisitor::didRace):
+        * heap/StochasticSpaceTimeMutatorScheduler.cpp:
+        (JSC::StochasticSpaceTimeMutatorScheduler::beginCollection):
+        (JSC::StochasticSpaceTimeMutatorScheduler::didExecuteConstraints):
+        * jit/JIT.cpp:
+        (JSC::JIT::link):
+        * jit/JITExceptions.cpp:
+        (JSC::genericUnwind):
+        * jit/JITOperations.cpp:
+        * jit/JITToDFGDeferredCompilationCallback.cpp:
+        (JSC::JITToDFGDeferredCompilationCallback::compilationDidBecomeReadyAsynchronously):
+        (JSC::JITToDFGDeferredCompilationCallback::compilationDidComplete):
+        * jit/JITWorklist.cpp:
+        (JSC::JITWorklist::Plan::finalize):
+        * jit/PolymorphicCallStubRoutine.cpp:
+        (JSC::PolymorphicCallNode::unlink):
+        * jit/Repatch.cpp:
+        (JSC::unlinkFor):
+        (JSC::linkVirtualFor):
+        * llint/LLIntSlowPaths.cpp:
+        (JSC::LLInt::jitCompileAndSetHeuristics):
+        (JSC::LLInt::entryOSR):
+        (JSC::LLInt::LLINT_SLOW_PATH_DECL):
+        * parser/ModuleAnalyzer.cpp:
+        (JSC::ModuleAnalyzer::analyze):
+        * runtime/JSModuleLoader.cpp:
+        (JSC::JSModuleLoader::importModule):
+        (JSC::JSModuleLoader::resolveSync):
+        (JSC::JSModuleLoader::fetch):
+        (JSC::JSModuleLoader::evaluate):
+        (JSC::moduleLoaderModuleDeclarationInstantiation):
+        * runtime/ScriptExecutable.cpp:
+        (JSC::ScriptExecutable::installCode):
+        * runtime/VM.cpp:
+        (JSC::VM::throwException):
+        * tools/CompilerTimingScope.cpp:
+        (JSC::CompilerTimingScope::CompilerTimingScope):
+        (JSC::CompilerTimingScope::~CompilerTimingScope):
+        * wasm/WasmMemory.cpp:
+        * wasm/js/JSWebAssembly.cpp:
+        (JSC::resolve):
+        * yarr/YarrJIT.cpp:
+        (JSC::Yarr::jitCompile):
+        * yarr/YarrPattern.cpp:
+        (JSC::Yarr::YarrPattern::compile):
+
+2020-01-16  Robin Morisset  <rmorisset@apple.com>
+
         Reduce the code generated by DFGSlowPathGenerator.h
         https://bugs.webkit.org/show_bug.cgi?id=206330
 
diff --git a/Source/JavaScriptCore/bytecode/BytecodeGeneratorification.cpp b/Source/JavaScriptCore/bytecode/BytecodeGeneratorification.cpp
index 33d2bee..f5852d9 100644
--- a/Source/JavaScriptCore/bytecode/BytecodeGeneratorification.cpp
+++ b/Source/JavaScriptCore/bytecode/BytecodeGeneratorification.cpp
@@ -300,7 +300,7 @@
 
 void performGeneratorification(BytecodeGenerator& bytecodeGenerator, UnlinkedCodeBlock* codeBlock, InstructionStreamWriter& instructions, SymbolTable* generatorFrameSymbolTable, int generatorFrameSymbolTableIndex)
 {
-    if (Options::dumpBytecodesBeforeGeneratorification())
+    if (UNLIKELY(Options::dumpBytecodesBeforeGeneratorification()))
         CodeBlockBytecodeDumper<UnlinkedCodeBlock>::dumpBlock(codeBlock, instructions, WTF::dataFile());
 
     BytecodeGeneratorification pass(bytecodeGenerator, codeBlock, instructions, generatorFrameSymbolTable, generatorFrameSymbolTableIndex);
diff --git a/Source/JavaScriptCore/bytecode/BytecodeLivenessAnalysis.cpp b/Source/JavaScriptCore/bytecode/BytecodeLivenessAnalysis.cpp
index 918e1d2..472a8d1 100644
--- a/Source/JavaScriptCore/bytecode/BytecodeLivenessAnalysis.cpp
+++ b/Source/JavaScriptCore/bytecode/BytecodeLivenessAnalysis.cpp
@@ -42,7 +42,7 @@
 {
     runLivenessFixpoint(codeBlock, codeBlock->instructions(), m_graph);
 
-    if (Options::dumpBytecodeLivenessResults())
+    if (UNLIKELY(Options::dumpBytecodeLivenessResults()))
         dumpResults(codeBlock);
 }
 
diff --git a/Source/JavaScriptCore/bytecode/CallLinkInfo.cpp b/Source/JavaScriptCore/bytecode/CallLinkInfo.cpp
index 6f1478b..d29f60e 100644
--- a/Source/JavaScriptCore/bytecode/CallLinkInfo.cpp
+++ b/Source/JavaScriptCore/bytecode/CallLinkInfo.cpp
@@ -209,7 +209,7 @@
     if (isLinked()) {
         if (stub()) {
             if (!stub()->visitWeak(vm)) {
-                if (Options::verboseOSR()) {
+                if (UNLIKELY(Options::verboseOSR())) {
                     dataLog(
                         "At ", m_codeOrigin, ", ", RawPointer(this), ": clearing call stub to ",
                         listDump(stub()->variants()), ", stub routine ", RawPointer(stub()),
@@ -220,14 +220,14 @@
             }
         } else if (!vm.heap.isMarked(m_calleeOrCodeBlock.get())) {
             if (isDirect()) {
-                if (Options::verboseOSR()) {
+                if (UNLIKELY(Options::verboseOSR())) {
                     dataLog(
                         "Clearing call to ", RawPointer(codeBlock()), " (",
                         pointerDump(codeBlock()), ").\n");
                 }
             } else {
                 if (callee()->type() == JSFunctionType) {
-                    if (Options::verboseOSR()) {
+                    if (UNLIKELY(Options::verboseOSR())) {
                         dataLog(
                             "Clearing call to ",
                             RawPointer(callee()), " (",
@@ -236,14 +236,14 @@
                     }
                     handleSpecificCallee(static_cast<JSFunction*>(callee()));
                 } else {
-                    if (Options::verboseOSR())
+                    if (UNLIKELY(Options::verboseOSR()))
                         dataLog("Clearing call to ", RawPointer(callee()), ".\n");
                     m_clearedByGC = true;
                 }
             }
             unlink(vm);
         } else if (isDirect() && !vm.heap.isMarked(m_lastSeenCalleeOrExecutable.get())) {
-            if (Options::verboseOSR()) {
+            if (UNLIKELY(Options::verboseOSR())) {
                 dataLog(
                     "Clearing call to ", RawPointer(executable()),
                     " because the executable is dead.\n");
diff --git a/Source/JavaScriptCore/bytecode/CodeBlock.cpp b/Source/JavaScriptCore/bytecode/CodeBlock.cpp
index 3f32fe8..aaefad2 100644
--- a/Source/JavaScriptCore/bytecode/CodeBlock.cpp
+++ b/Source/JavaScriptCore/bytecode/CodeBlock.cpp
@@ -1219,8 +1219,7 @@
             StructureID oldStructureID = metadata.m_modeMetadata.defaultMode.structureID;
             if (!oldStructureID || vm.heap.isMarked(vm.heap.structureIDTable().get(oldStructureID)))
                 return;
-            if (Options::verboseOSR())
-                dataLogF("Clearing LLInt property access.\n");
+            dataLogLnIf(Options::verboseOSR(), "Clearing LLInt property access.");
             LLIntPrototypeLoadAdaptiveStructureWatchpoint::clearLLIntGetByIdCache(metadata);
         });
 
@@ -1228,8 +1227,7 @@
             StructureID oldStructureID = metadata.m_structureID;
             if (!oldStructureID || vm.heap.isMarked(vm.heap.structureIDTable().get(oldStructureID)))
                 return;
-            if (Options::verboseOSR())
-                dataLogF("Clearing LLInt property access.\n");
+            dataLogLnIf(Options::verboseOSR(), "Clearing LLInt property access.");
             metadata.m_structureID = 0;
             metadata.m_offset = 0;
         });
@@ -1242,8 +1240,7 @@
                 && (!newStructureID || vm.heap.isMarked(vm.heap.structureIDTable().get(newStructureID)))
                 && (!chain || vm.heap.isMarked(chain)))
                 return;
-            if (Options::verboseOSR())
-                dataLogF("Clearing LLInt put transition.\n");
+            dataLogLnIf(Options::verboseOSR(), "Clearing LLInt put transition.");
             metadata.m_oldStructureID = 0;
             metadata.m_offset = 0;
             metadata.m_newStructureID = 0;
@@ -1292,8 +1289,7 @@
             WriteBarrierBase<SymbolTable>& symbolTable = metadata.m_symbolTable;
             if (!symbolTable || vm.heap.isMarked(symbolTable.get()))
                 return;
-            if (Options::verboseOSR())
-                dataLogF("Clearing dead symbolTable %p.\n", symbolTable.get());
+            dataLogLnIf(Options::verboseOSR(), "Clearing dead symbolTable ", RawPointer(symbolTable.get()));
             symbolTable.clear();
         });
 
@@ -1305,8 +1301,7 @@
             WriteBarrierBase<Structure>& structure = metadata.m_structure;
             if (!structure || vm.heap.isMarked(structure.get()))
                 return;
-            if (Options::verboseOSR())
-                dataLogF("Clearing scope access with structure %p.\n", structure.get());
+            dataLogLnIf(Options::verboseOSR(), "Clearing scope access with structure ", RawPointer(structure.get()));
             structure.clear();
         };
 
@@ -1321,8 +1316,7 @@
             auto& instruction = instructions().at(std::get<1>(pair.key));
             OpcodeID opcode = instruction->opcodeID();
             if (opcode == op_get_by_id) {
-                if (Options::verboseOSR())
-                    dataLogF("Clearing LLInt property access.\n");
+                dataLogLnIf(Options::verboseOSR(), "Clearing LLInt property access.");
                 LLIntPrototypeLoadAdaptiveStructureWatchpoint::clearLLIntGetByIdCache(instruction->as<OpGetById>().metadata(this));
             }
             return true;
@@ -1341,8 +1335,7 @@
 
     forEachLLIntCallLinkInfo([&](LLIntCallLinkInfo& callLinkInfo) {
         if (callLinkInfo.isLinked() && !vm.heap.isMarked(callLinkInfo.callee())) {
-            if (Options::verboseOSR())
-                dataLog("Clearing LLInt call from ", *this, "\n");
+            dataLogLnIf(Options::verboseOSR(), "Clearing LLInt call from ", *this);
             callLinkInfo.unlink();
         }
         if (callLinkInfo.lastSeenCallee() && !vm.heap.isMarked(callLinkInfo.lastSeenCallee()))
@@ -2178,8 +2171,7 @@
 {
     CodeBlock* callerCodeBlock = callerFrame->codeBlock();
     
-    if (Options::verboseCallLink())
-        dataLog("Noticing call link from ", pointerDump(callerCodeBlock), " to ", *this, "\n");
+    dataLogLnIf(Options::verboseCallLink(), "Noticing call link from ", pointerDump(callerCodeBlock), " to ", *this);
     
 #if ENABLE(DFG_JIT)
     if (!m_shouldAlwaysBeInlined)
@@ -2187,8 +2179,7 @@
     
     if (!callerCodeBlock) {
         m_shouldAlwaysBeInlined = false;
-        if (Options::verboseCallLink())
-            dataLog("    Clearing SABI because caller is native.\n");
+        dataLogLnIf(Options::verboseCallLink(), "    Clearing SABI because caller is native.");
         return;
     }
 
@@ -2203,8 +2194,7 @@
     
     if (!DFG::isSmallEnoughToInlineCodeInto(callerCodeBlock)) {
         m_shouldAlwaysBeInlined = false;
-        if (Options::verboseCallLink())
-            dataLog("    Clearing SABI because caller is too large.\n");
+        dataLogLnIf(Options::verboseCallLink(), "    Clearing SABI because caller is too large.");
         return;
     }
 
@@ -2214,15 +2204,13 @@
         // ensures that a function is SABI only if it is called no more frequently than
         // any of its callers.
         m_shouldAlwaysBeInlined = false;
-        if (Options::verboseCallLink())
-            dataLog("    Clearing SABI because caller is in LLInt.\n");
+        dataLogLnIf(Options::verboseCallLink(), "    Clearing SABI because caller is in LLInt.");
         return;
     }
     
     if (JITCode::isOptimizingJIT(callerCodeBlock->jitType())) {
         m_shouldAlwaysBeInlined = false;
-        if (Options::verboseCallLink())
-            dataLog("    Clearing SABI bcause caller was already optimized.\n");
+        dataLogLnIf(Options::verboseCallLink(), "    Clearing SABI bcause caller was already optimized.");
         return;
     }
     
@@ -2231,8 +2219,7 @@
         // optimized anytime soon. For eval code this is particularly true since we
         // delay eval optimization by a *lot*.
         m_shouldAlwaysBeInlined = false;
-        if (Options::verboseCallLink())
-            dataLog("    Clearing SABI because caller is not a function.\n");
+        dataLogLnIf(Options::verboseCallLink(), "    Clearing SABI because caller is not a function.");
         return;
     }
 
@@ -2241,8 +2228,7 @@
     vm().topCallFrame->iterate(vm(), functor);
 
     if (functor.didRecurse()) {
-        if (Options::verboseCallLink())
-            dataLog("    Clearing SABI because recursion was detected.\n");
+        dataLogLnIf(Options::verboseCallLink(), "    Clearing SABI because recursion was detected.");
         m_shouldAlwaysBeInlined = false;
         return;
     }
@@ -2255,8 +2241,7 @@
     if (canCompile(callerCodeBlock->capabilityLevelState()))
         return;
     
-    if (Options::verboseCallLink())
-        dataLog("    Clearing SABI because the caller is not a DFG candidate.\n");
+    dataLogLnIf(Options::verboseCallLink(), "    Clearing SABI because the caller is not a DFG candidate.");
     
     m_shouldAlwaysBeInlined = false;
 #endif
@@ -2404,12 +2389,9 @@
     
     result *= codeTypeThresholdMultiplier();
     
-    if (Options::verboseOSR()) {
-        dataLog(
-            *this, ": bytecode cost is ", bytecodeCost,
-            ", scaling execution counter by ", result, " * ", codeTypeThresholdMultiplier(),
-            "\n");
-    }
+    dataLogLnIf(Options::verboseOSR(),
+        *this, ": bytecode cost is ", bytecodeCost,
+        ", scaling execution counter by ", result, " * ", codeTypeThresholdMultiplier());
     return result;
 }
 
@@ -2498,22 +2480,19 @@
 
 void CodeBlock::optimizeNextInvocation()
 {
-    if (Options::verboseOSR())
-        dataLog(*this, ": Optimizing next invocation.\n");
+    dataLogLnIf(Options::verboseOSR(), *this, ": Optimizing next invocation.");
     m_jitExecuteCounter.setNewThreshold(0, this);
 }
 
 void CodeBlock::dontOptimizeAnytimeSoon()
 {
-    if (Options::verboseOSR())
-        dataLog(*this, ": Not optimizing anytime soon.\n");
+    dataLogLnIf(Options::verboseOSR(), *this, ": Not optimizing anytime soon.");
     m_jitExecuteCounter.deferIndefinitely();
 }
 
 void CodeBlock::optimizeAfterWarmUp()
 {
-    if (Options::verboseOSR())
-        dataLog(*this, ": Optimizing after warm-up.\n");
+    dataLogLnIf(Options::verboseOSR(), *this, ": Optimizing after warm-up.");
 #if ENABLE(DFG_JIT)
     m_jitExecuteCounter.setNewThreshold(
         adjustedCounterValue(Options::thresholdForOptimizeAfterWarmUp()), this);
@@ -2522,8 +2501,7 @@
 
 void CodeBlock::optimizeAfterLongWarmUp()
 {
-    if (Options::verboseOSR())
-        dataLog(*this, ": Optimizing after long warm-up.\n");
+    dataLogLnIf(Options::verboseOSR(), *this, ": Optimizing after long warm-up.");
 #if ENABLE(DFG_JIT)
     m_jitExecuteCounter.setNewThreshold(
         adjustedCounterValue(Options::thresholdForOptimizeAfterLongWarmUp()), this);
@@ -2532,8 +2510,7 @@
 
 void CodeBlock::optimizeSoon()
 {
-    if (Options::verboseOSR())
-        dataLog(*this, ": Optimizing soon.\n");
+    dataLogLnIf(Options::verboseOSR(), *this, ": Optimizing soon.");
 #if ENABLE(DFG_JIT)
     m_jitExecuteCounter.setNewThreshold(
         adjustedCounterValue(Options::thresholdForOptimizeSoon()), this);
@@ -2542,8 +2519,7 @@
 
 void CodeBlock::forceOptimizationSlowPathConcurrently()
 {
-    if (Options::verboseOSR())
-        dataLog(*this, ": Forcing slow path concurrently.\n");
+    dataLogLnIf(Options::verboseOSR(), *this, ": Forcing slow path concurrently.");
     m_jitExecuteCounter.forceSlowPathConcurrently();
 }
 
@@ -2552,7 +2528,7 @@
 {
     JITType type = jitType();
     if (type != JITType::BaselineJIT) {
-        dataLog(*this, ": expected to have baseline code but have ", type, "\n");
+        dataLogLn(*this, ": expected to have baseline code but have ", type);
         CRASH_WITH_INFO(bitwise_cast<uintptr_t>(jitCode().get()), static_cast<uint8_t>(type));
     }
     
@@ -2756,8 +2732,7 @@
 
 bool CodeBlock::shouldOptimizeNow()
 {
-    if (Options::verboseOSR())
-        dataLog("Considering optimizing ", *this, "...\n");
+    dataLogLnIf(Options::verboseOSR(), "Considering optimizing ", *this, "...");
 
     if (m_optimizationDelayCounter >= Options::maximumOptimizationDelay())
         return true;
diff --git a/Source/JavaScriptCore/bytecode/DFGExitProfile.cpp b/Source/JavaScriptCore/bytecode/DFGExitProfile.cpp
index a82f92d..2551372 100644
--- a/Source/JavaScriptCore/bytecode/DFGExitProfile.cpp
+++ b/Source/JavaScriptCore/bytecode/DFGExitProfile.cpp
@@ -50,8 +50,7 @@
 
     CODEBLOCK_LOG_EVENT(owner, "frequentExit", (site));
     
-    if (Options::verboseExitProfile())
-        dataLog(pointerDump(owner), ": Adding exit site: ", site, "\n");
+    dataLogLnIf(Options::verboseExitProfile(), pointerDump(owner), ": Adding exit site: ", site);
 
     ExitProfile& profile = owner->unlinkedCodeBlock()->exitProfile();
     
diff --git a/Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp b/Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp
index 7effad0..9ffc555 100644
--- a/Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp
+++ b/Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp
@@ -7421,7 +7421,7 @@
             deferredSourceDump.append(DeferredSourceDump(codeBlock->baselineVersion()));
     }
 
-    if (Options::dumpBytecodeAtDFGTime()) {
+    if (UNLIKELY(Options::dumpBytecodeAtDFGTime())) {
         dataLog("Parsing ", *codeBlock);
         if (inlineCallFrame()) {
             dataLog(
@@ -7435,7 +7435,7 @@
     
     Vector<InstructionStream::Offset, 32> jumpTargets;
     computePreciseJumpTargets(codeBlock, jumpTargets);
-    if (Options::dumpBytecodeAtDFGTime()) {
+    if (UNLIKELY(Options::dumpBytecodeAtDFGTime())) {
         dataLog("Jump targets: ");
         CommaPrinter comma;
         for (unsigned i = 0; i < jumpTargets.size(); ++i)
diff --git a/Source/JavaScriptCore/dfg/DFGCFAPhase.cpp b/Source/JavaScriptCore/dfg/DFGCFAPhase.cpp
index a240149..f9b4597 100644
--- a/Source/JavaScriptCore/dfg/DFGCFAPhase.cpp
+++ b/Source/JavaScriptCore/dfg/DFGCFAPhase.cpp
@@ -268,7 +268,7 @@
     AbstractInterpreter<InPlaceAbstractState> m_interpreter;
     BlockSet m_blocksWithOSR;
     
-    bool m_verbose;
+    const bool m_verbose;
     
     bool m_changed;
     unsigned m_count;
diff --git a/Source/JavaScriptCore/dfg/DFGJITCode.cpp b/Source/JavaScriptCore/dfg/DFGJITCode.cpp
index 9b21df3..2de9f1a 100644
--- a/Source/JavaScriptCore/dfg/DFGJITCode.cpp
+++ b/Source/JavaScriptCore/dfg/DFGJITCode.cpp
@@ -128,24 +128,21 @@
 void JITCode::optimizeNextInvocation(CodeBlock* codeBlock)
 {
     ASSERT(codeBlock->jitType() == JITType::DFGJIT);
-    if (Options::verboseOSR())
-        dataLog(*codeBlock, ": FTL-optimizing next invocation.\n");
+    dataLogLnIf(Options::verboseOSR(), *codeBlock, ": FTL-optimizing next invocation.");
     tierUpCounter.setNewThreshold(0, codeBlock);
 }
 
 void JITCode::dontOptimizeAnytimeSoon(CodeBlock* codeBlock)
 {
     ASSERT(codeBlock->jitType() == JITType::DFGJIT);
-    if (Options::verboseOSR())
-        dataLog(*codeBlock, ": Not FTL-optimizing anytime soon.\n");
+    dataLogLnIf(Options::verboseOSR(), *codeBlock, ": Not FTL-optimizing anytime soon.");
     tierUpCounter.deferIndefinitely();
 }
 
 void JITCode::optimizeAfterWarmUp(CodeBlock* codeBlock)
 {
     ASSERT(codeBlock->jitType() == JITType::DFGJIT);
-    if (Options::verboseOSR())
-        dataLog(*codeBlock, ": FTL-optimizing after warm-up.\n");
+    dataLogLnIf(Options::verboseOSR(), *codeBlock, ": FTL-optimizing after warm-up.");
     CodeBlock* baseline = codeBlock->baselineVersion();
     tierUpCounter.setNewThreshold(
         baseline->adjustedCounterValue(Options::thresholdForFTLOptimizeAfterWarmUp()),
@@ -155,8 +152,7 @@
 void JITCode::optimizeSoon(CodeBlock* codeBlock)
 {
     ASSERT(codeBlock->jitType() == JITType::DFGJIT);
-    if (Options::verboseOSR())
-        dataLog(*codeBlock, ": FTL-optimizing soon.\n");
+    dataLogLnIf(Options::verboseOSR(), *codeBlock, ": FTL-optimizing soon.");
     CodeBlock* baseline = codeBlock->baselineVersion();
     tierUpCounter.setNewThreshold(
         baseline->adjustedCounterValue(Options::thresholdForFTLOptimizeSoon()),
@@ -166,8 +162,7 @@
 void JITCode::forceOptimizationSlowPathConcurrently(CodeBlock* codeBlock)
 {
     ASSERT(codeBlock->jitType() == JITType::DFGJIT);
-    if (Options::verboseOSR())
-        dataLog(*codeBlock, ": Forcing slow path concurrently for FTL entry.\n");
+    dataLogLnIf(Options::verboseOSR(), *codeBlock, ": Forcing slow path concurrently for FTL entry.");
     tierUpCounter.forceSlowPathConcurrently();
 }
 
@@ -204,8 +199,8 @@
 void JITCode::setOSREntryBlock(VM& vm, const JSCell* owner, CodeBlock* osrEntryBlock)
 {
     if (Options::verboseOSR()) {
-        dataLog(RawPointer(this), ": Setting OSR entry block to ", RawPointer(osrEntryBlock), "\n");
-        dataLog("OSR entries will go to ", osrEntryBlock->jitCode()->ftlForOSREntry()->addressForCall(ArityCheckNotRequired), "\n");
+        dataLogLn(RawPointer(this), ": Setting OSR entry block to ", RawPointer(osrEntryBlock));
+        dataLogLn("OSR entries will go to ", osrEntryBlock->jitCode()->ftlForOSREntry()->addressForCall(ArityCheckNotRequired));
     }
     m_osrEntryBlock.set(vm, owner, osrEntryBlock);
 }
diff --git a/Source/JavaScriptCore/dfg/DFGJumpReplacement.cpp b/Source/JavaScriptCore/dfg/DFGJumpReplacement.cpp
index 1ebf694..9d3994c 100644
--- a/Source/JavaScriptCore/dfg/DFGJumpReplacement.cpp
+++ b/Source/JavaScriptCore/dfg/DFGJumpReplacement.cpp
@@ -36,8 +36,9 @@
 
 void JumpReplacement::fire()
 {
-    if (Options::dumpDisassembly())
-        dataLogF("Firing jump replacement watchpoint from %p, to %p.\n", m_source.dataLocation(), m_destination.dataLocation());
+    dataLogLnIf(Options::dumpDisassembly(),
+        "Firing jump replacement watchpoint from ", RawPointer(m_source.dataLocation()),
+        " to ", RawPointer(m_destination.dataLocation()));
     MacroAssembler::replaceWithJump(m_source, m_destination);
 }
 
diff --git a/Source/JavaScriptCore/dfg/DFGOSREntry.cpp b/Source/JavaScriptCore/dfg/DFGOSREntry.cpp
index 4497308..a20d7d3 100644
--- a/Source/JavaScriptCore/dfg/DFGOSREntry.cpp
+++ b/Source/JavaScriptCore/dfg/DFGOSREntry.cpp
@@ -103,11 +103,9 @@
     if (!Options::useOSREntryToDFG())
         return nullptr;
 
-    if (Options::verboseOSR()) {
-        dataLog(
-            "DFG OSR in ", *codeBlock->alternative(), " -> ", *codeBlock,
-            " from ", bytecodeIndex, "\n");
-    }
+    dataLogLnIf(Options::verboseOSR(),
+        "DFG OSR in ", *codeBlock->alternative(), " -> ", *codeBlock,
+        " from ", bytecodeIndex);
     
     sanitizeStackForVM(vm);
     
@@ -134,8 +132,7 @@
         //   be super rare. For now, if it does happen, it'll cause some compilation
         //   thrashing.
         
-        if (Options::verboseOSR())
-            dataLog("    OSR failed because the target code block is not DFG.\n");
+        dataLogLnIf(Options::verboseOSR(), "    OSR failed because the target code block is not DFG.");
         return nullptr;
     }
     
@@ -143,8 +140,7 @@
     OSREntryData* entry = jitCode->osrEntryDataForBytecodeIndex(bytecodeIndex);
     
     if (!entry) {
-        if (Options::verboseOSR())
-            dataLogF("    OSR failed because the entrypoint was optimized out.\n");
+        dataLogLnIf(Options::verboseOSR(), "    OSR failed because the entrypoint was optimized out.");
         return nullptr;
     }
     
@@ -182,11 +178,9 @@
             value = callFrame->argument(argument - 1);
         
         if (!entry->m_expectedValues.argument(argument).validateOSREntryValue(value, FlushedJSValue)) {
-            if (Options::verboseOSR()) {
-                dataLog(
-                    "    OSR failed because argument ", argument, " is ", value,
-                    ", expected ", entry->m_expectedValues.argument(argument), ".\n");
-            }
+            dataLogLnIf(Options::verboseOSR(),
+                "    OSR failed because argument ", argument, " is ", value,
+                ", expected ", entry->m_expectedValues.argument(argument));
             return nullptr;
         }
     }
@@ -237,13 +231,11 @@
     
     unsigned frameSizeForCheck = jitCode->common.requiredRegisterCountForExecutionAndExit();
     if (UNLIKELY(!vm.ensureStackCapacityFor(&callFrame->registers()[virtualRegisterForLocal(frameSizeForCheck - 1).offset()]))) {
-        if (Options::verboseOSR())
-            dataLogF("    OSR failed because stack growth failed.\n");
+        dataLogLnIf(Options::verboseOSR(), "    OSR failed because stack growth failed.");
         return nullptr;
     }
     
-    if (Options::verboseOSR())
-        dataLogF("    OSR should succeed.\n");
+    dataLogLnIf(Options::verboseOSR(), "    OSR should succeed.");
 
     // At this point we're committed to entering. We will do some work to set things up,
     // but we also rely on our caller recognizing that when we return a non-null pointer,
@@ -262,8 +254,7 @@
     
     void* targetPC = entry->m_machineCode.executableAddress();
     RELEASE_ASSERT(codeBlock->jitCode()->contains(entry->m_machineCode.untaggedExecutableAddress()));
-    if (Options::verboseOSR())
-        dataLogF("    OSR using target PC %p.\n", targetPC);
+    dataLogLnIf(Options::verboseOSR(), "    OSR using target PC ", RawPointer(targetPC));
     RELEASE_ASSERT(targetPC);
     *bitwise_cast<void**>(scratch + 1) = retagCodePtr(targetPC, OSREntryPtrTag, bitwise_cast<PtrTag>(callFrame));
 
@@ -324,8 +315,7 @@
     
     *bitwise_cast<CodeBlock**>(pivot - 1 - CallFrameSlot::codeBlock) = codeBlock;
     
-    if (Options::verboseOSR())
-        dataLogF("    OSR returning data buffer %p.\n", scratch);
+    dataLogLnIf(Options::verboseOSR(), "    OSR returning data buffer ", RawPointer(scratch));
     return scratch;
 }
 
diff --git a/Source/JavaScriptCore/dfg/DFGOSRExit.cpp b/Source/JavaScriptCore/dfg/DFGOSRExit.cpp
index 1b8e278..42cb5e6 100644
--- a/Source/JavaScriptCore/dfg/DFGOSRExit.cpp
+++ b/Source/JavaScriptCore/dfg/DFGOSRExit.cpp
@@ -1110,7 +1110,7 @@
     jit.jitAssertTagsInPlace();
 
     // Pro-forma stuff.
-    if (Options::printEachOSRExit()) {
+    if (UNLIKELY(Options::printEachOSRExit())) {
         SpeculationFailureDebugInfo* debugInfo = new SpeculationFailureDebugInfo;
         debugInfo->codeBlock = jit.codeBlock();
         debugInfo->kind = exit.m_kind;
diff --git a/Source/JavaScriptCore/dfg/DFGObjectAllocationSinkingPhase.cpp b/Source/JavaScriptCore/dfg/DFGObjectAllocationSinkingPhase.cpp
index a99597f..e25b68a 100644
--- a/Source/JavaScriptCore/dfg/DFGObjectAllocationSinkingPhase.cpp
+++ b/Source/JavaScriptCore/dfg/DFGObjectAllocationSinkingPhase.cpp
@@ -807,7 +807,7 @@
         m_combinedLiveness = CombinedLiveness(m_graph);
 
         CString graphBeforeSinking;
-        if (Options::verboseValidationFailure() && Options::validateGraphAtEachPhase()) {
+        if (UNLIKELY(Options::verboseValidationFailure() && Options::validateGraphAtEachPhase())) {
             StringPrintStream out;
             m_graph.dump(out);
             graphBeforeSinking = out.toCString();
diff --git a/Source/JavaScriptCore/dfg/DFGOperations.cpp b/Source/JavaScriptCore/dfg/DFGOperations.cpp
index bb5c835..d208479 100644
--- a/Source/JavaScriptCore/dfg/DFGOperations.cpp
+++ b/Source/JavaScriptCore/dfg/DFGOperations.cpp
@@ -3684,8 +3684,7 @@
     
     sanitizeStackForVM(codeBlock->vm());
 
-    if (Options::verboseOSR())
-        dataLog(*codeBlock, ": Entered reoptimize\n");
+    dataLogLnIf(Options::verboseOSR(), *codeBlock, ": Entered reoptimize");
     // We must be called with the baseline code block.
     ASSERT(JITCode::isBaselineCode(codeBlock->jitType()));
 
@@ -3696,8 +3695,7 @@
     // sure bet that we don't have anything else left to do.
     CodeBlock* replacement = codeBlock->replacement();
     if (!replacement || replacement == codeBlock) {
-        if (Options::verboseOSR())
-            dataLog(*codeBlock, ": Not reoptimizing because we've already been jettisoned.\n");
+        dataLogLnIf(Options::verboseOSR(), *codeBlock, ": Not reoptimizing because we've already been jettisoned.");
         return;
     }
     
@@ -3723,8 +3721,7 @@
         && optimizedCodeBlock->shouldReoptimizeFromLoopNow();
     
     if (!didExitABunch && !didGetStuckInLoop) {
-        if (Options::verboseOSR())
-            dataLog(*codeBlock, ": Not reoptimizing ", *optimizedCodeBlock, " because it either didn't exit enough or didn't loop enough after exit.\n");
+        dataLogLnIf(Options::verboseOSR(), *codeBlock, ": Not reoptimizing ", *optimizedCodeBlock, " because it either didn't exit enough or didn't loop enough after exit.");
         codeBlock->optimizeAfterLongWarmUp();
         return;
     }
@@ -3742,8 +3739,7 @@
 {
     if (codeBlock->baselineVersion()->m_didFailFTLCompilation) {
         CODEBLOCK_LOG_EVENT(codeBlock, "abortFTLCompile", ());
-        if (Options::verboseOSR())
-            dataLog("Deferring FTL-optimization of ", *codeBlock, " indefinitely because there was an FTL failure.\n");
+        dataLogLnIf(Options::verboseOSR(), "Deferring FTL-optimization of ", *codeBlock, " indefinitely because there was an FTL failure.");
         jitCode->dontOptimizeAnytimeSoon(codeBlock);
         return false;
     }
@@ -3751,8 +3747,7 @@
     if (!codeBlock->hasOptimizedReplacement()
         && !jitCode->checkIfOptimizationThresholdReached(codeBlock)) {
         CODEBLOCK_LOG_EVENT(codeBlock, "delayFTLCompile", ("counter = ", jitCode->tierUpCounter));
-        if (Options::verboseOSR())
-            dataLog("Choosing not to FTL-optimize ", *codeBlock, " yet.\n");
+        dataLogLnIf(Options::verboseOSR(), "Choosing not to FTL-optimize ", *codeBlock, " yet.");
         return false;
     }
     return true;
@@ -3794,8 +3789,7 @@
         CODEBLOCK_LOG_EVENT(codeBlock, "delayFTLCompile", ("compiled and failed"));
         // This means that we finished compiling, but failed somehow; in that case the
         // thresholds will be set appropriately.
-        if (Options::verboseOSR())
-            dataLog("Code block ", *codeBlock, " was compiled but it doesn't have an optimized replacement.\n");
+        dataLogLnIf(Options::verboseOSR(), "Code block ", *codeBlock, " was compiled but it doesn't have an optimized replacement.");
         return;
     }
 
@@ -3827,11 +3821,8 @@
     
     JITCode* jitCode = codeBlock->jitCode()->dfg();
     
-    if (Options::verboseOSR()) {
-        dataLog(
-            *codeBlock, ": Entered triggerTierUpNow with executeCounter = ",
-            jitCode->tierUpCounter, "\n");
-    }
+    dataLogLnIf(Options::verboseOSR(),
+        *codeBlock, ": Entered triggerTierUpNow with executeCounter = ", jitCode->tierUpCounter);
 
     if (shouldTriggerFTLCompile(codeBlock, jitCode))
         triggerFTLReplacementCompile(vm, codeBlock, jitCode);
@@ -3906,8 +3897,7 @@
         if (iter != jitCode->bytecodeIndexToStreamIndex.end()) {
             unsigned streamIndex = iter->value;
             if (CodeBlock* entryBlock = jitCode->osrEntryBlock()) {
-                if (Options::verboseOSR())
-                    dataLog("OSR entry: From ", RawPointer(jitCode), " got entry block ", RawPointer(entryBlock), "\n");
+                dataLogLnIf(Options::verboseOSR(), "OSR entry: From ", RawPointer(jitCode), " got entry block ", RawPointer(entryBlock));
                 if (void* address = FTL::prepareOSREntry(vm, callFrame, codeBlock, entryBlock, originBytecodeIndex, streamIndex)) {
                     CODEBLOCK_LOG_EVENT(entryBlock, "osrEntry", ("at ", originBytecodeIndex));
                     return retagCodePtr<char*>(address, JSEntryPtrTag, bitwise_cast<PtrTag>(callFrame));
@@ -3919,8 +3909,7 @@
     if (worklistState == Worklist::Compiled) {
         CODEBLOCK_LOG_EVENT(codeBlock, "delayFTLCompile", ("compiled and failed"));
         // This means that compilation failed and we already set the thresholds.
-        if (Options::verboseOSR())
-            dataLog("Code block ", *codeBlock, " was compiled but it doesn't have an optimized replacement.\n");
+        dataLogLnIf(Options::verboseOSR(), "Code block ", *codeBlock, " was compiled but it doesn't have an optimized replacement.");
         return nullptr;
     }
 
@@ -4005,8 +3994,7 @@
 
                 // This is where we ask the outer to loop to immediately compile itself if program
                 // control reaches it.
-                if (Options::verboseOSR())
-                    dataLog("Inner-loop ", originBytecodeIndex, " in ", *codeBlock, " setting parent loop ", osrEntryCandidate, "'s trigger and backing off.\n");
+                dataLogLnIf(Options::verboseOSR(), "Inner-loop ", originBytecodeIndex, " in ", *codeBlock, " setting parent loop ", osrEntryCandidate, "'s trigger and backing off.");
                 jitCode->tierUpEntryTriggers.set(osrEntryCandidate, JITCode::TriggerReason::StartCompilation);
                 return true;
             }
@@ -4060,8 +4048,7 @@
     // It's possible that the for-entry compile already succeeded. In that case OSR
     // entry will succeed unless we ran out of stack. It's not clear what we should do.
     // We signal to try again after a while if that happens.
-    if (Options::verboseOSR())
-        dataLog("Immediate OSR entry: From ", RawPointer(jitCode), " got entry block ", RawPointer(jitCode->osrEntryBlock()), "\n");
+    dataLogLnIf(Options::verboseOSR(), "Immediate OSR entry: From ", RawPointer(jitCode), " got entry block ", RawPointer(jitCode->osrEntryBlock()));
 
     void* address = FTL::prepareOSREntry(vm, callFrame, codeBlock, jitCode->osrEntryBlock(), originBytecodeIndex, streamIndex);
     if (!address)
@@ -4081,17 +4068,13 @@
     sanitizeStackForVM(vm);
 
     if (codeBlock->jitType() != JITType::DFGJIT) {
-        dataLog("Unexpected code block in DFG->FTL trigger tier up now in loop: ", *codeBlock, "\n");
+        dataLogLn("Unexpected code block in DFG->FTL trigger tier up now in loop: ", *codeBlock);
         RELEASE_ASSERT_NOT_REACHED();
     }
 
     JITCode* jitCode = codeBlock->jitCode()->dfg();
 
-    if (Options::verboseOSR()) {
-        dataLog(
-            *codeBlock, ": Entered triggerTierUpNowInLoop with executeCounter = ",
-            jitCode->tierUpCounter, "\n");
-    }
+    dataLogLnIf(Options::verboseOSR(), *codeBlock, ": Entered triggerTierUpNowInLoop with executeCounter = ", jitCode->tierUpCounter);
 
     if (jitCode->tierUpInLoopHierarchy.contains(bytecodeIndex))
         tierUpCommon(vm, callFrame, bytecodeIndex, false);
@@ -4123,11 +4106,7 @@
 
     JITCode* jitCode = codeBlock->jitCode()->dfg();
 
-    if (Options::verboseOSR()) {
-        dataLog(
-            *codeBlock, ": Entered triggerOSREntryNow with executeCounter = ",
-            jitCode->tierUpCounter, "\n");
-    }
+    dataLogLnIf(Options::verboseOSR(), *codeBlock, ": Entered triggerOSREntryNow with executeCounter = ", jitCode->tierUpCounter);
 
     return tierUpCommon(vm, callFrame, bytecodeIndex, true);
 }
diff --git a/Source/JavaScriptCore/dfg/DFGPlan.cpp b/Source/JavaScriptCore/dfg/DFGPlan.cpp
index d800079..9d6d102 100644
--- a/Source/JavaScriptCore/dfg/DFGPlan.cpp
+++ b/Source/JavaScriptCore/dfg/DFGPlan.cpp
@@ -496,7 +496,7 @@
         if (UNLIKELY(computeCompileTimes()))
             m_timeBeforeFTL = MonotonicTime::now();
         
-        if (Options::b3AlwaysFailsBeforeCompile()) {
+        if (UNLIKELY(Options::b3AlwaysFailsBeforeCompile())) {
             FTL::fail(state);
             return FTLPath;
         }
@@ -505,7 +505,7 @@
         if (safepointResult.didGetCancelled())
             return CancelPath;
         
-        if (Options::b3AlwaysFailsBeforeLink()) {
+        if (UNLIKELY(Options::b3AlwaysFailsBeforeLink())) {
             FTL::fail(state);
             return FTLPath;
         }
diff --git a/Source/JavaScriptCore/dfg/DFGToFTLDeferredCompilationCallback.cpp b/Source/JavaScriptCore/dfg/DFGToFTLDeferredCompilationCallback.cpp
index c67e7a00..eaf3516 100644
--- a/Source/JavaScriptCore/dfg/DFGToFTLDeferredCompilationCallback.cpp
+++ b/Source/JavaScriptCore/dfg/DFGToFTLDeferredCompilationCallback.cpp
@@ -48,11 +48,9 @@
 void ToFTLDeferredCompilationCallback::compilationDidBecomeReadyAsynchronously(
     CodeBlock* codeBlock, CodeBlock* profiledDFGCodeBlock)
 {
-    if (Options::verboseOSR()) {
-        dataLog(
-            "Optimizing compilation of ", codeBlock, " (for ", profiledDFGCodeBlock,
-            ") did become ready.\n");
-    }
+    dataLogLnIf(Options::verboseOSR(),
+        "Optimizing compilation of ", codeBlock, " (for ", profiledDFGCodeBlock,
+        ") did become ready.");
     
     profiledDFGCodeBlock->jitCode()->dfg()->forceOptimizationSlowPathConcurrently(
         profiledDFGCodeBlock);
@@ -61,18 +59,14 @@
 void ToFTLDeferredCompilationCallback::compilationDidComplete(
     CodeBlock* codeBlock, CodeBlock* profiledDFGCodeBlock, CompilationResult result)
 {
-    if (Options::verboseOSR()) {
-        dataLog(
-            "Optimizing compilation of ", codeBlock, " (for ", profiledDFGCodeBlock,
-            ") result: ", result, "\n");
-    }
+    dataLogLnIf(Options::verboseOSR(),
+        "Optimizing compilation of ", codeBlock, " (for ", profiledDFGCodeBlock,
+        ") result: ", result);
     
     if (profiledDFGCodeBlock->replacement() != profiledDFGCodeBlock) {
-        if (Options::verboseOSR()) {
-            dataLog(
-                "Dropping FTL code block ", codeBlock, " on the floor because the "
-                "DFG code block ", profiledDFGCodeBlock, " was jettisoned.\n");
-        }
+        dataLogLnIf(Options::verboseOSR(),
+            "Dropping FTL code block ", codeBlock, " on the floor because the "
+            "DFG code block ", profiledDFGCodeBlock, " was jettisoned.");
         return;
     }
     
diff --git a/Source/JavaScriptCore/dfg/DFGToFTLForOSREntryDeferredCompilationCallback.cpp b/Source/JavaScriptCore/dfg/DFGToFTLForOSREntryDeferredCompilationCallback.cpp
index a42949c..02ac4f3 100644
--- a/Source/JavaScriptCore/dfg/DFGToFTLForOSREntryDeferredCompilationCallback.cpp
+++ b/Source/JavaScriptCore/dfg/DFGToFTLForOSREntryDeferredCompilationCallback.cpp
@@ -52,11 +52,9 @@
 void ToFTLForOSREntryDeferredCompilationCallback::compilationDidBecomeReadyAsynchronously(
     CodeBlock* codeBlock, CodeBlock* profiledDFGCodeBlock)
 {
-    if (Options::verboseOSR()) {
-        dataLog(
-            "Optimizing compilation of ", *codeBlock, " (for ", *profiledDFGCodeBlock,
-            ") did become ready.\n");
-    }
+    dataLogLnIf(Options::verboseOSR(),
+        "Optimizing compilation of ", *codeBlock, " (for ", *profiledDFGCodeBlock,
+        ") did become ready.");
 
     *m_forcedOSREntryTrigger = JITCode::TriggerReason::CompilationDone;
 }
@@ -64,11 +62,9 @@
 void ToFTLForOSREntryDeferredCompilationCallback::compilationDidComplete(
     CodeBlock* codeBlock, CodeBlock* profiledDFGCodeBlock, CompilationResult result)
 {
-    if (Options::verboseOSR()) {
-        dataLog(
-            "Optimizing compilation of ", *codeBlock, " (for ", *profiledDFGCodeBlock,
-            ") result: ", result, "\n");
-    }
+    dataLogLnIf(Options::verboseOSR(),
+        "Optimizing compilation of ", *codeBlock, " (for ", *profiledDFGCodeBlock,
+        ") result: ", result);
     
     JITCode* jitCode = profiledDFGCodeBlock->jitCode()->dfg();
         
diff --git a/Source/JavaScriptCore/dfg/DFGWorklist.cpp b/Source/JavaScriptCore/dfg/DFGWorklist.cpp
index e14eb2a8..65965aa 100644
--- a/Source/JavaScriptCore/dfg/DFGWorklist.cpp
+++ b/Source/JavaScriptCore/dfg/DFGWorklist.cpp
@@ -105,8 +105,7 @@
             m_plan->notifyCompiling();
         }
         
-        if (Options::verboseCompilationQueue())
-            dataLog(m_worklist, ": Compiling ", m_plan->key(), " asynchronously\n");
+        dataLogLnIf(Options::verboseCompilationQueue(), m_worklist, ": Compiling ", m_plan->key(), " asynchronously");
         
         // There's no way for the GC to be safepointing since we own rightToRun.
         if (m_plan->vm()->heap.worldIsStopped()) {
@@ -143,8 +142,7 @@
     
     void threadDidStart() override
     {
-        if (Options::verboseCompilationQueue())
-            dataLog(m_worklist, ": Thread started\n");
+        dataLogLnIf(Options::verboseCompilationQueue(), m_worklist, ": Thread started");
         
         if (m_relativePriority)
             Thread::current().changePriority(m_relativePriority);
@@ -156,8 +154,7 @@
     {
         // We're holding the Worklist::m_lock, so we should be careful not to deadlock.
         
-        if (Options::verboseCompilationQueue())
-            dataLog(m_worklist, ": Thread will stop\n");
+        dataLogLnIf(Options::verboseCompilationQueue(), m_worklist, ": Thread will stop");
         
         ASSERT(!m_plan);
         
@@ -336,8 +333,7 @@
         RefPtr<Plan> plan = myReadyPlans.takeLast();
         CompilationKey currentKey = plan->key();
         
-        if (Options::verboseCompilationQueue())
-            dataLog(*this, ": Completing ", currentKey, "\n");
+        dataLogLnIf(Options::verboseCompilationQueue(), *this, ": Completing ", currentKey);
 
         RELEASE_ASSERT(plan->stage() == Plan::Ready);
 
diff --git a/Source/JavaScriptCore/ftl/FTLOSREntry.cpp b/Source/JavaScriptCore/ftl/FTLOSREntry.cpp
index 9331771..afbf6ed 100644
--- a/Source/JavaScriptCore/ftl/FTLOSREntry.cpp
+++ b/Source/JavaScriptCore/ftl/FTLOSREntry.cpp
@@ -52,27 +52,23 @@
         dfgCode->clearOSREntryBlockAndResetThresholds(dfgCodeBlock);
         return 0;
     }
-    
-    if (Options::verboseOSR()) {
-        dataLog(
-            "FTL OSR from ", *dfgCodeBlock, " to ", *entryCodeBlock, " at ",
-            bytecodeIndex, ".\n");
-    }
+
+    dataLogLnIf(Options::verboseOSR(),
+        "FTL OSR from ", *dfgCodeBlock, " to ", *entryCodeBlock, " at ",
+        bytecodeIndex);
     
     if (bytecodeIndex)
         jsCast<ScriptExecutable*>(executable)->setDidTryToEnterInLoop(true);
 
     if (bytecodeIndex != entryCode->bytecodeIndex()) {
-        if (Options::verboseOSR())
-            dataLog("    OSR failed because we don't have an entrypoint for ", bytecodeIndex, "; ours is for ", entryCode->bytecodeIndex(), "\n");
+        dataLogLnIf(Options::verboseOSR(), "    OSR failed because we don't have an entrypoint for ", bytecodeIndex, "; ours is for ", entryCode->bytecodeIndex());
         return 0;
     }
     
     Operands<Optional<JSValue>> values;
     dfgCode->reconstruct(callFrame, dfgCodeBlock, CodeOrigin(bytecodeIndex), streamIndex, values);
     
-    if (Options::verboseOSR())
-        dataLog("    Values at entry: ", values, "\n");
+    dataLogLnIf(Options::verboseOSR(), "    Values at entry: ", values);
     
     for (int argument = values.numberOfArguments(); argument--;) {
         JSValue valueOnStack = callFrame->r(virtualRegisterForArgument(argument).offset()).asanUnsafeJSValue();
@@ -101,16 +97,14 @@
     
     int stackFrameSize = entryCode->common.requiredRegisterCountForExecutionAndExit();
     if (UNLIKELY(!vm.ensureStackCapacityFor(&callFrame->registers()[virtualRegisterForLocal(stackFrameSize - 1).offset()]))) {
-        if (Options::verboseOSR())
-            dataLog("    OSR failed because stack growth failed.\n");
+        dataLogLnIf(Options::verboseOSR(), "    OSR failed because stack growth failed.");
         return 0;
     }
     
     callFrame->setCodeBlock(entryCodeBlock);
     
     void* result = entryCode->addressForCall(ArityCheckNotRequired).executableAddress();
-    if (Options::verboseOSR())
-        dataLog("    Entry will succeed, going to address ", RawPointer(result), "\n");
+    dataLogLnIf(Options::verboseOSR(), "    Entry will succeed, going to address ", RawPointer(result));
     
     return result;
 }
diff --git a/Source/JavaScriptCore/heap/Heap.cpp b/Source/JavaScriptCore/heap/Heap.cpp
index 67540d9..e3e836e 100644
--- a/Source/JavaScriptCore/heap/Heap.cpp
+++ b/Source/JavaScriptCore/heap/Heap.cpp
@@ -396,7 +396,7 @@
 void Heap::lastChanceToFinalize()
 {
     MonotonicTime before;
-    if (Options::logGC()) {
+    if (UNLIKELY(Options::logGC())) {
         before = MonotonicTime::now();
         dataLog("[GC<", RawPointer(this), ">: shutdown ");
     }
@@ -414,17 +414,15 @@
         }
         m_collectContinuouslyThread->waitForCompletion();
     }
-    
-    if (Options::logGC())
-        dataLog("1");
+
+    dataLogIf(Options::logGC(), "1");
     
     // Prevent new collections from being started. This is probably not even necessary, since we're not
     // going to call into anything that starts collections. Still, this makes the algorithm more
     // obviously sound.
     m_isSafeToCollect = false;
     
-    if (Options::logGC())
-        dataLog("2");
+    dataLogIf(Options::logGC(), "2");
 
     bool isCollecting;
     {
@@ -433,8 +431,7 @@
         isCollecting = m_lastServedTicket < m_lastGrantedTicket;
     }
     if (isCollecting) {
-        if (Options::logGC())
-            dataLog("...]\n");
+        dataLogIf(Options::logGC(), "...]\n");
         
         // Wait for the current collection to finish.
         waitForCollector(
@@ -443,11 +440,9 @@
                 return m_lastServedTicket == m_lastGrantedTicket;
             });
         
-        if (Options::logGC())
-            dataLog("[GC<", RawPointer(this), ">: shutdown ");
+        dataLogIf(Options::logGC(), "[GC<", RawPointer(this), ">: shutdown ");
     }
-    if (Options::logGC())
-        dataLog("3");
+    dataLogIf(Options::logGC(), "3");
 
     RELEASE_ASSERT(m_requests.isEmpty());
     RELEASE_ASSERT(m_lastServedTicket == m_lastGrantedTicket);
@@ -462,14 +457,12 @@
             m_threadCondition->notifyOne(locker);
     }
 
-    if (Options::logGC())
-        dataLog("4");
+    dataLogIf(Options::logGC(), "4");
     
     if (!stopped)
         m_thread->join();
     
-    if (Options::logGC())
-        dataLog("5 ");
+    dataLogIf(Options::logGC(), "5 ");
 
     if (UNLIKELY(Options::dumpHeapStatisticsAtVMDestruction()))
         dumpHeapStatisticsAtVMDestruction();
@@ -483,8 +476,7 @@
     
     m_objectSpace.freeMemory();
     
-    if (Options::logGC())
-        dataLog((MonotonicTime::now() - before).milliseconds(), "ms]\n");
+    dataLogIf(Options::logGC(), (MonotonicTime::now() - before).milliseconds(), "ms]\n");
 }
 
 void Heap::releaseDelayedReleasedObjects()
@@ -1050,13 +1042,13 @@
 void Heap::sweepSynchronously()
 {
     MonotonicTime before { };
-    if (Options::logGC()) {
+    if (UNLIKELY(Options::logGC())) {
         dataLog("Full sweep: ", capacity() / 1024, "kb ");
         before = MonotonicTime::now();
     }
     m_objectSpace.sweepBlocks();
     m_objectSpace.shrink();
-    if (Options::logGC()) {
+    if (UNLIKELY(Options::logGC())) {
         MonotonicTime after = MonotonicTime::now();
         dataLog("=> ", capacity() / 1024, "kb, ", (after - before).milliseconds(), "ms");
     }
@@ -1096,11 +1088,9 @@
         
         bool alreadySweptInCollectSync = shouldSweepSynchronously();
         if (!alreadySweptInCollectSync) {
-            if (Options::logGC())
-                dataLog("[GC<", RawPointer(this), ">: ");
+            dataLogIf(Options::logGC(), "[GC<", RawPointer(this), ">: ");
             sweepSynchronously();
-            if (Options::logGC())
-                dataLog("]\n");
+            dataLogIf(Options::logGC(), "]\n");
         }
         m_objectSpace.assertNoUnswept();
         
@@ -1264,8 +1254,7 @@
         m_currentRequest = m_requests.first();
     }
         
-    if (Options::logGC())
-        dataLog("[GC<", RawPointer(this), ">: START ", gcConductorShortName(conn), " ", capacity() / 1024, "kb ");
+    dataLogIf(Options::logGC(), "[GC<", RawPointer(this), ">: START ", gcConductorShortName(conn), " ", capacity() / 1024, "kb ");
 
     m_beforeGC = MonotonicTime::now();
 
@@ -1273,7 +1262,7 @@
         vm().random().setSeed(cryptographicallyRandomNumber());
 
     if (m_collectionScope) {
-        dataLog("Collection scope already set during GC: ", *m_collectionScope, "\n");
+        dataLogLn("Collection scope already set during GC: ", *m_collectionScope);
         RELEASE_ASSERT_NOT_REACHED();
     }
     
@@ -1334,7 +1323,7 @@
     m_constraintSet->didStartMarking();
     
     m_scheduler->beginCollection();
-    if (Options::logGC())
+    if (UNLIKELY(Options::logGC()))
         m_scheduler->log();
     
     // After this, we will almost certainly fall through all of the "slotVisitor.isEmpty()"
@@ -1362,7 +1351,7 @@
     
     SlotVisitor& slotVisitor = *m_collectorSlotVisitor;
     
-    if (Options::logGC()) {
+    if (UNLIKELY(Options::logGC())) {
         HashMap<const char*, size_t> visitMap;
         forEachSlotVisitor(
             [&] (SlotVisitor& slotVisitor) {
@@ -1406,8 +1395,7 @@
         m_scheduler->didExecuteConstraints();
     }
         
-    if (Options::logGC())
-        dataLog(slotVisitor.collectorMarkStack().size(), "+", m_mutatorMarkStack->size() + slotVisitor.mutatorMarkStack().size(), " ");
+    dataLogIf(Options::logGC(), slotVisitor.collectorMarkStack().size(), "+", m_mutatorMarkStack->size() + slotVisitor.mutatorMarkStack().size(), " ");
         
     {
         ParallelModeEnabler enabler(slotVisitor);
@@ -1433,7 +1421,7 @@
 
     m_scheduler->willResume();
         
-    if (Options::logGC()) {
+    if (UNLIKELY(Options::logGC())) {
         double thisPauseMS = (MonotonicTime::now() - m_stopTime).milliseconds();
         dataLog("p=", thisPauseMS, "ms (max ", maxPauseMS(thisPauseMS), ")...]\n");
     }
@@ -1477,12 +1465,11 @@
 
 NEVER_INLINE bool Heap::runReloopPhase(GCConductor conn)
 {
-    if (Options::logGC())
-        dataLog("[GC<", RawPointer(this), ">: ", gcConductorShortName(conn), " ");
+    dataLogIf(Options::logGC(), "[GC<", RawPointer(this), ">: ", gcConductorShortName(conn), " ");
     
     m_scheduler->didStop();
     
-    if (Options::logGC())
+    if (UNLIKELY(Options::logGC()))
         m_scheduler->log();
     
     return changePhase(conn, CollectorPhase::Fixpoint);
@@ -1549,7 +1536,7 @@
         m_objectSpace.dumpBits();
     }
     
-    if (Options::logGC()) {
+    if (UNLIKELY(Options::logGC())) {
         double thisPauseMS = (m_afterGC - m_stopTime).milliseconds();
         dataLog("p=", thisPauseMS, "ms (max ", maxPauseMS(thisPauseMS), "), cycle ", (m_afterGC - m_beforeGC).milliseconds(), "ms END]\n");
     }
@@ -1562,8 +1549,7 @@
     }
     ParkingLot::unparkAll(&m_worldState);
 
-    if (false)
-        dataLog("GC END!\n");
+    dataLogLnIf(Options::logGC(), "GC END!");
 
     setNeedFinalize();
 
@@ -2090,7 +2076,7 @@
 void Heap::finalize()
 {
     MonotonicTime before;
-    if (Options::logGC()) {
+    if (UNLIKELY(Options::logGC())) {
         before = MonotonicTime::now();
         dataLog("[GC<", RawPointer(this), ">: finalize ");
     }
@@ -2113,7 +2099,7 @@
     if (shouldSweepSynchronously())
         sweepSynchronously();
 
-    if (Options::logGC()) {
+    if (UNLIKELY(Options::logGC())) {
         MonotonicTime after = MonotonicTime::now();
         dataLog((after - before).milliseconds(), "ms]\n");
     }
@@ -2177,22 +2163,15 @@
 
 void Heap::willStartCollection()
 {
-    if (Options::logGC())
-        dataLog("=> ");
+    dataLogIf(Options::logGC(), "=> ");
     
     if (shouldDoFullCollection()) {
         m_collectionScope = CollectionScope::Full;
         m_shouldDoFullCollection = false;
-        if (Options::logGC())
-            dataLog("FullCollection, ");
-        if (false)
-            dataLog("Full collection!\n");
+        dataLogIf(Options::logGC(), "FullCollection, ");
     } else {
         m_collectionScope = CollectionScope::Eden;
-        if (Options::logGC())
-            dataLog("EdenCollection, ");
-        if (false)
-            dataLog("Eden collection!\n");
+        dataLogIf(Options::logGC(), "EdenCollection, ");
     }
     if (m_collectionScope && m_collectionScope.value() == CollectionScope::Full) {
         m_sizeBeforeLastFullCollect = m_sizeAfterLastCollect + m_bytesAllocatedThisCycle;
@@ -2351,8 +2330,7 @@
         dataLog("sizeAfterLastCollect = ", m_sizeAfterLastCollect, "\n");
     m_bytesAllocatedThisCycle = 0;
 
-    if (Options::logGC())
-        dataLog("=> ", currentHeapSize / 1024, "kb, ");
+    dataLogIf(Options::logGC(), "=> ", currentHeapSize / 1024, "kb, ");
 }
 
 void Heap::didFinishCollection()
@@ -2891,7 +2869,7 @@
 void Heap::notifyIsSafeToCollect()
 {
     MonotonicTime before;
-    if (Options::logGC()) {
+    if (UNLIKELY(Options::logGC())) {
         before = MonotonicTime::now();
         dataLog("[GC<", RawPointer(this), ">: starting ");
     }
@@ -2931,8 +2909,7 @@
             });
     }
     
-    if (Options::logGC())
-        dataLog((MonotonicTime::now() - before).milliseconds(), "ms]\n");
+    dataLogIf(Options::logGC(), (MonotonicTime::now() - before).milliseconds(), "ms]\n");
 }
 
 void Heap::preventCollection()
diff --git a/Source/JavaScriptCore/heap/MarkStackMergingConstraint.cpp b/Source/JavaScriptCore/heap/MarkStackMergingConstraint.cpp
index 01a1fda..05b546d 100644
--- a/Source/JavaScriptCore/heap/MarkStackMergingConstraint.cpp
+++ b/Source/JavaScriptCore/heap/MarkStackMergingConstraint.cpp
@@ -53,8 +53,7 @@
     size_t size = m_heap.m_mutatorMarkStack->size() + m_heap.m_raceMarkStack->size();
     visitor.addToVisitCount(size);
     
-    if (Options::logGC())
-        dataLog("(", size, ")");
+    dataLogIf(Options::logGC(), "(", size, ")");
 }
 
 void MarkStackMergingConstraint::executeImpl(SlotVisitor& visitor)
diff --git a/Source/JavaScriptCore/heap/MarkedSpace.cpp b/Source/JavaScriptCore/heap/MarkedSpace.cpp
index 149ce8d..e80b04c 100644
--- a/Source/JavaScriptCore/heap/MarkedSpace.cpp
+++ b/Source/JavaScriptCore/heap/MarkedSpace.cpp
@@ -45,15 +45,14 @@
         [] {
             result = new Vector<size_t>();
             
-            if (Options::dumpSizeClasses()) {
+            if (UNLIKELY(Options::dumpSizeClasses())) {
                 dataLog("Block size: ", MarkedBlock::blockSize, "\n");
                 dataLog("Footer size: ", sizeof(MarkedBlock::Footer), "\n");
             }
             
             auto add = [&] (size_t sizeClass) {
                 sizeClass = WTF::roundUpToMultipleOf<MarkedBlock::atomSize>(sizeClass);
-                if (Options::dumpSizeClasses())
-                    dataLog("Adding JSC MarkedSpace size class: ", sizeClass, "\n");
+                dataLogLnIf(Options::dumpSizeClasses(), "Adding JSC MarkedSpace size class: ", sizeClass);
                 // Perform some validation as we go.
                 RELEASE_ASSERT(!(sizeClass % MarkedSpace::sizeStep));
                 if (result->isEmpty())
@@ -73,19 +72,14 @@
             // the wasted space at the tail end of a MarkedBlock) while proceeding roughly in an exponential
             // way starting at just above the precise size classes to four cells per block.
             
-            if (Options::dumpSizeClasses())
-                dataLog("    Marked block payload size: ", static_cast<size_t>(MarkedSpace::blockPayload), "\n");
+            dataLogLnIf(Options::dumpSizeClasses(), "    Marked block payload size: ", static_cast<size_t>(MarkedSpace::blockPayload));
             
             for (unsigned i = 0; ; ++i) {
                 double approximateSize = MarkedSpace::preciseCutoff * pow(Options::sizeClassProgression(), i);
-                
-                if (Options::dumpSizeClasses())
-                    dataLog("    Next size class as a double: ", approximateSize, "\n");
+                dataLogLnIf(Options::dumpSizeClasses(), "    Next size class as a double: ", approximateSize);
         
                 size_t approximateSizeInBytes = static_cast<size_t>(approximateSize);
-        
-                if (Options::dumpSizeClasses())
-                    dataLog("    Next size class as bytes: ", approximateSizeInBytes, "\n");
+                dataLogLnIf(Options::dumpSizeClasses(), "    Next size class as bytes: ", approximateSizeInBytes);
         
                 // Make sure that the computer did the math correctly.
                 RELEASE_ASSERT(approximateSizeInBytes >= MarkedSpace::preciseCutoff);
@@ -95,25 +89,19 @@
                 
                 size_t sizeClass =
                     WTF::roundUpToMultipleOf<MarkedSpace::sizeStep>(approximateSizeInBytes);
-                
-                if (Options::dumpSizeClasses())
-                    dataLog("    Size class: ", sizeClass, "\n");
+                dataLogLnIf(Options::dumpSizeClasses(), "    Size class: ", sizeClass);
                 
                 // Optimize the size class so that there isn't any slop at the end of the block's
                 // payload.
                 unsigned cellsPerBlock = MarkedSpace::blockPayload / sizeClass;
                 size_t possiblyBetterSizeClass = (MarkedSpace::blockPayload / cellsPerBlock) & ~(MarkedSpace::sizeStep - 1);
-                
-                if (Options::dumpSizeClasses())
-                    dataLog("    Possibly better size class: ", possiblyBetterSizeClass, "\n");
+                dataLogLnIf(Options::dumpSizeClasses(), "    Possibly better size class: ", possiblyBetterSizeClass);
 
                 // The size class we just came up with is better than the other one if it reduces
                 // total wastage assuming we only allocate cells of that size.
                 size_t originalWastage = MarkedSpace::blockPayload - cellsPerBlock * sizeClass;
                 size_t newWastage = (possiblyBetterSizeClass - sizeClass) * cellsPerBlock;
-                
-                if (Options::dumpSizeClasses())
-                    dataLog("    Original wastage: ", originalWastage, ", new wastage: ", newWastage, "\n");
+                dataLogLnIf(Options::dumpSizeClasses(), "    Original wastage: ", originalWastage, ", new wastage: ", newWastage);
                 
                 size_t betterSizeClass;
                 if (newWastage > originalWastage)
@@ -121,8 +109,7 @@
                 else
                     betterSizeClass = possiblyBetterSizeClass;
                 
-                if (Options::dumpSizeClasses())
-                    dataLog("    Choosing size class: ", betterSizeClass, "\n");
+                dataLogLnIf(Options::dumpSizeClasses(), "    Choosing size class: ", betterSizeClass);
                 
                 if (betterSizeClass == result->last()) {
                     // Defense for when expStep is small.
@@ -149,8 +136,7 @@
                 result->shrinkCapacity(it - result->begin());
             }
 
-            if (Options::dumpSizeClasses())
-                dataLog("JSC Heap MarkedSpace size class dump: ", listDump(*result), "\n");
+            dataLogLnIf(Options::dumpSizeClasses(), "JSC Heap MarkedSpace size class dump: ", listDump(*result));
 
             // We have an optimiation in MarkedSpace::optimalSizeFor() that assumes things about
             // the size class table. This checks our results against that function's assumptions.
diff --git a/Source/JavaScriptCore/heap/MarkingConstraint.cpp b/Source/JavaScriptCore/heap/MarkingConstraint.cpp
index 3bab767..6f4dc17 100644
--- a/Source/JavaScriptCore/heap/MarkingConstraint.cpp
+++ b/Source/JavaScriptCore/heap/MarkingConstraint.cpp
@@ -72,8 +72,7 @@
 
 void MarkingConstraint::prepareToExecute(const AbstractLocker& constraintSolvingLocker, SlotVisitor& visitor)
 {
-    if (Options::logGC())
-        dataLog(abbreviatedName());
+    dataLogIf(Options::logGC(), abbreviatedName());
     VisitCounter visitCounter(visitor);
     prepareToExecuteImpl(constraintSolvingLocker, visitor);
     m_lastVisitCount = visitCounter.visitCount();
diff --git a/Source/JavaScriptCore/heap/MarkingConstraintSet.cpp b/Source/JavaScriptCore/heap/MarkingConstraintSet.cpp
index 1780c08..fea8082 100644
--- a/Source/JavaScriptCore/heap/MarkingConstraintSet.cpp
+++ b/Source/JavaScriptCore/heap/MarkingConstraintSet.cpp
@@ -83,8 +83,7 @@
 bool MarkingConstraintSet::executeConvergence(SlotVisitor& visitor)
 {
     bool result = executeConvergenceImpl(visitor);
-    if (Options::logGC())
-        dataLog(" ");
+    dataLogIf(Options::logGC(), " ");
     return result;
 }
 
@@ -104,8 +103,7 @@
     
     unsigned iteration = m_iteration++;
     
-    if (Options::logGC())
-        dataLog("i#", iteration, ":");
+    dataLogIf(Options::logGC(), "i#", iteration, ":");
 
     if (iteration == 1) {
         // First iteration is before any visitor draining, so it's unlikely to trigger any constraints
@@ -174,8 +172,7 @@
 {
     for (auto& constraint : m_set)
         constraint->execute(visitor);
-    if (Options::logGC())
-        dataLog(" ");
+    dataLogIf(Options::logGC(), " ");
 }
 
 } // namespace JSC
diff --git a/Source/JavaScriptCore/heap/MarkingConstraintSolver.cpp b/Source/JavaScriptCore/heap/MarkingConstraintSolver.cpp
index cbbbd31..3735bc9 100644
--- a/Source/JavaScriptCore/heap/MarkingConstraintSolver.cpp
+++ b/Source/JavaScriptCore/heap/MarkingConstraintSolver.cpp
@@ -61,14 +61,12 @@
     RELEASE_ASSERT(!m_numThreadsThatMayProduceWork);
     
     if (Options::useParallelMarkingConstraintSolver()) {
-        if (Options::logGC())
-            dataLog(preference == ParallelWorkFirst ? "P" : "N", "<");
+        dataLogIf(Options::logGC(), preference == ParallelWorkFirst ? "P" : "N", "<");
         
         m_heap.runFunctionInParallel(
             [&] (SlotVisitor& visitor) { runExecutionThread(visitor, preference, pickNext); });
         
-        if (Options::logGC())
-            dataLog(">");
+        dataLogIf(Options::logGC(), ">");
     } else
         runExecutionThread(m_mainVisitor, preference, pickNext);
     
diff --git a/Source/JavaScriptCore/heap/SlotVisitor.cpp b/Source/JavaScriptCore/heap/SlotVisitor.cpp
index 1a7164e..f316fde 100644
--- a/Source/JavaScriptCore/heap/SlotVisitor.cpp
+++ b/Source/JavaScriptCore/heap/SlotVisitor.cpp
@@ -292,7 +292,7 @@
 {
     ASSERT(m_heap.isMarked(cell));
 #if CPU(X86_64)
-    if (Options::dumpZappedCellCrashData()) {
+    if (UNLIKELY(Options::dumpZappedCellCrashData())) {
         if (UNLIKELY(cell->isZapped()))
             reportZappedCellAndCrash(cell);
     }
@@ -397,7 +397,7 @@
         // FIXME: This could be so much better.
         // https://bugs.webkit.org/show_bug.cgi?id=162462
 #if CPU(X86_64)
-        if (Options::dumpZappedCellCrashData()) {
+        if (UNLIKELY(Options::dumpZappedCellCrashData())) {
             Structure* structure = cell->structure(vm());
             if (LIKELY(structure)) {
                 const MethodTable* methodTable = &structure->classInfo()->methodTable;
@@ -795,8 +795,7 @@
 
 void SlotVisitor::didRace(const VisitRaceKey& race)
 {
-    if (Options::verboseVisitRace())
-        dataLog(toCString("GC visit race: ", race, "\n"));
+    dataLogLnIf(Options::verboseVisitRace(), toCString("GC visit race: ", race));
     
     auto locker = holdLock(heap()->m_raceMarkStackLock);
     JSCell* cell = race.cell();
diff --git a/Source/JavaScriptCore/heap/StochasticSpaceTimeMutatorScheduler.cpp b/Source/JavaScriptCore/heap/StochasticSpaceTimeMutatorScheduler.cpp
index 158355a..0177d97 100644
--- a/Source/JavaScriptCore/heap/StochasticSpaceTimeMutatorScheduler.cpp
+++ b/Source/JavaScriptCore/heap/StochasticSpaceTimeMutatorScheduler.cpp
@@ -77,8 +77,7 @@
         Options::concurrentGCMaxHeadroom() *
         std::max<double>(m_bytesAllocatedThisCycleAtTheBeginning, m_heap.m_maxEdenSize);
     
-    if (Options::logGC())
-        dataLog("ca=", m_bytesAllocatedThisCycleAtTheBeginning / 1024, "kb h=", (m_bytesAllocatedThisCycleAtTheEnd - m_bytesAllocatedThisCycleAtTheBeginning) / 1024, "kb ");
+    dataLogIf(Options::logGC(), "ca=", m_bytesAllocatedThisCycleAtTheBeginning / 1024, "kb h=", (m_bytesAllocatedThisCycleAtTheEnd - m_bytesAllocatedThisCycleAtTheBeginning) / 1024, "kb ");
     
     m_beforeConstraints = MonotonicTime::now();
 }
@@ -110,8 +109,7 @@
         constraintExecutionDuration * m_pauseScale,
         m_minimumPause);
     
-    if (Options::logGC())
-        dataLog("tp=", m_targetPause.milliseconds(), "ms ");
+    dataLogIf(Options::logGC(), "tp=", m_targetPause.milliseconds(), "ms ");
     
     m_plannedResumeTime = snapshot.now() + m_targetPause;
 }
diff --git a/Source/JavaScriptCore/jit/JIT.cpp b/Source/JavaScriptCore/jit/JIT.cpp
index d771794..e4248f2 100644
--- a/Source/JavaScriptCore/jit/JIT.cpp
+++ b/Source/JavaScriptCore/jit/JIT.cpp
@@ -906,7 +906,7 @@
 
     MacroAssemblerCodePtr<JSEntryPtrTag> withArityCheck = patchBuffer.locationOf<JSEntryPtrTag>(m_arityCheck);
 
-    if (Options::dumpDisassembly()) {
+    if (UNLIKELY(Options::dumpDisassembly())) {
         m_disassembler->dump(patchBuffer);
         patchBuffer.didAlreadyDisassemble();
     }
diff --git a/Source/JavaScriptCore/jit/JITExceptions.cpp b/Source/JavaScriptCore/jit/JITExceptions.cpp
index b7d0ca2..1610dce 100644
--- a/Source/JavaScriptCore/jit/JITExceptions.cpp
+++ b/Source/JavaScriptCore/jit/JITExceptions.cpp
@@ -47,7 +47,7 @@
 {
     auto scope = DECLARE_CATCH_SCOPE(vm);
     CallFrame* topJSCallFrame = vm.topJSCallFrame();
-    if (Options::breakOnThrow()) {
+    if (UNLIKELY(Options::breakOnThrow())) {
         CodeBlock* codeBlock = topJSCallFrame->codeBlock();
         dataLog("In call frame ", RawPointer(topJSCallFrame), " for code block ", codeBlock, "\n");
         CRASH();
diff --git a/Source/JavaScriptCore/jit/JITOperations.cpp b/Source/JavaScriptCore/jit/JITOperations.cpp
index 082a783..dba1013 100644
--- a/Source/JavaScriptCore/jit/JITOperations.cpp
+++ b/Source/JavaScriptCore/jit/JITOperations.cpp
@@ -1539,8 +1539,7 @@
     if (!codeBlock->checkIfOptimizationThresholdReached()) {
         CODEBLOCK_LOG_EVENT(codeBlock, "delayOptimizeToDFG", ("counter = ", codeBlock->jitExecuteCounter()));
         codeBlock->updateAllPredictions();
-        if (UNLIKELY(Options::verboseOSR()))
-            dataLog("Choosing not to optimize ", *codeBlock, " yet, because the threshold hasn't been reached.\n");
+        dataLogLnIf(Options::verboseOSR(), "Choosing not to optimize ", *codeBlock, " yet, because the threshold hasn't been reached.");
         return encodeResult(0, 0);
     }
     
@@ -1554,8 +1553,7 @@
     if (codeBlock->m_shouldAlwaysBeInlined) {
         CODEBLOCK_LOG_EVENT(codeBlock, "delayOptimizeToDFG", ("should always be inlined"));
         updateAllPredictionsAndOptimizeAfterWarmUp(codeBlock);
-        if (UNLIKELY(Options::verboseOSR()))
-            dataLog("Choosing not to optimize ", *codeBlock, " yet, because m_shouldAlwaysBeInlined == true.\n");
+        dataLogLnIf(Options::verboseOSR(), "Choosing not to optimize ", *codeBlock, " yet, because m_shouldAlwaysBeInlined == true.");
         return encodeResult(0, 0);
     }
 
@@ -1610,14 +1608,12 @@
         if (!codeBlock->hasOptimizedReplacement()) {
             CODEBLOCK_LOG_EVENT(codeBlock, "delayOptimizeToDFG", ("compiled and failed"));
             codeBlock->updateAllPredictions();
-            if (UNLIKELY(Options::verboseOSR()))
-                dataLog("Code block ", *codeBlock, " was compiled but it doesn't have an optimized replacement.\n");
+            dataLogLnIf(Options::verboseOSR(), "Code block ", *codeBlock, " was compiled but it doesn't have an optimized replacement.");
             return encodeResult(0, 0);
         }
     } else if (codeBlock->hasOptimizedReplacement()) {
         CodeBlock* replacement = codeBlock->replacement();
-        if (UNLIKELY(Options::verboseOSR()))
-            dataLog("Considering OSR ", codeBlock, " -> ", replacement, ".\n");
+        dataLogLnIf(Options::verboseOSR(), "Considering OSR ", codeBlock, " -> ", replacement, ".");
         // If we have an optimized replacement, then it must be the case that we entered
         // cti_optimize from a loop. That's because if there's an optimized replacement,
         // then all calls to this function will be relinked to the replacement and so
@@ -1633,27 +1629,22 @@
         // additional checking anyway, to reduce the amount of recompilation thrashing.
         if (replacement->shouldReoptimizeFromLoopNow()) {
             CODEBLOCK_LOG_EVENT(codeBlock, "delayOptimizeToDFG", ("should reoptimize from loop now"));
-            if (UNLIKELY(Options::verboseOSR())) {
-                dataLog(
-                    "Triggering reoptimization of ", codeBlock,
-                    "(", replacement, ") (in loop).\n");
-            }
+            dataLogLnIf(Options::verboseOSR(),
+                "Triggering reoptimization of ", codeBlock,
+                "(", replacement, ") (in loop).");
             replacement->jettison(Profiler::JettisonDueToBaselineLoopReoptimizationTrigger, CountReoptimization);
             return encodeResult(0, 0);
         }
     } else {
         if (!codeBlock->shouldOptimizeNow()) {
             CODEBLOCK_LOG_EVENT(codeBlock, "delayOptimizeToDFG", ("insufficient profiling"));
-            if (UNLIKELY(Options::verboseOSR())) {
-                dataLog(
-                    "Delaying optimization for ", *codeBlock,
-                    " because of insufficient profiling.\n");
-            }
+            dataLogLnIf(Options::verboseOSR(),
+                "Delaying optimization for ", *codeBlock,
+                " because of insufficient profiling.");
             return encodeResult(0, 0);
         }
 
-        if (UNLIKELY(Options::verboseOSR()))
-            dataLog("Triggering optimized compilation of ", *codeBlock, "\n");
+        dataLogLnIf(Options::verboseOSR(), "Triggering optimized compilation of ", *codeBlock);
 
         unsigned numVarsWithValues;
         if (bytecodeIndex)
@@ -1685,10 +1676,7 @@
     
     if (void* dataBuffer = DFG::prepareOSREntry(vm, callFrame, optimizedCodeBlock, bytecodeIndex)) {
         CODEBLOCK_LOG_EVENT(optimizedCodeBlock, "osrEntry", ("at bc#", bytecodeIndex));
-        if (UNLIKELY(Options::verboseOSR())) {
-            dataLog(
-                "Performing OSR ", codeBlock, " -> ", optimizedCodeBlock, ".\n");
-        }
+        dataLogLnIf(Options::verboseOSR(), "Performing OSR ", codeBlock, " -> ", optimizedCodeBlock);
 
         codeBlock->optimizeSoon();
         codeBlock->unlinkedCodeBlock()->setDidOptimize(TrueTriState);
@@ -1697,12 +1685,10 @@
         return encodeResult(targetPC, dataBuffer);
     }
 
-    if (UNLIKELY(Options::verboseOSR())) {
-        dataLog(
-            "Optimizing ", codeBlock, " -> ", codeBlock->replacement(),
-            " succeeded, OSR failed, after a delay of ",
-            codeBlock->optimizationDelayCounter(), ".\n");
-    }
+    dataLogLnIf(Options::verboseOSR(),
+        "Optimizing ", codeBlock, " -> ", codeBlock->replacement(),
+        " succeeded, OSR failed, after a delay of ",
+        codeBlock->optimizationDelayCounter());
 
     // Count the OSR failure as a speculation failure. If this happens a lot, then
     // reoptimize.
@@ -1718,11 +1704,9 @@
     // reoptimization trigger.
     if (optimizedCodeBlock->shouldReoptimizeNow()) {
         CODEBLOCK_LOG_EVENT(codeBlock, "delayOptimizeToDFG", ("should reoptimize now"));
-        if (UNLIKELY(Options::verboseOSR())) {
-            dataLog(
-                "Triggering reoptimization of ", codeBlock, " -> ",
-                codeBlock->replacement(), " (after OSR fail).\n");
-        }
+        dataLogLnIf(Options::verboseOSR(),
+            "Triggering reoptimization of ", codeBlock, " -> ",
+            codeBlock->replacement(), " (after OSR fail).");
         optimizedCodeBlock->jettison(Profiler::JettisonDueToBaselineLoopReoptimizationTriggerOnOSREntryFail, CountReoptimization);
         return encodeResult(0, 0);
     }
diff --git a/Source/JavaScriptCore/jit/JITToDFGDeferredCompilationCallback.cpp b/Source/JavaScriptCore/jit/JITToDFGDeferredCompilationCallback.cpp
index 9020d35..201ec9b 100644
--- a/Source/JavaScriptCore/jit/JITToDFGDeferredCompilationCallback.cpp
+++ b/Source/JavaScriptCore/jit/JITToDFGDeferredCompilationCallback.cpp
@@ -47,8 +47,7 @@
     ASSERT_UNUSED(profiledDFGCodeBlock, !profiledDFGCodeBlock);
     ASSERT(codeBlock->alternative()->jitType() == JITType::BaselineJIT);
     
-    if (Options::verboseOSR())
-        dataLog("Optimizing compilation of ", *codeBlock, " did become ready.\n");
+    dataLogLnIf(Options::verboseOSR(), "Optimizing compilation of ", *codeBlock, " did become ready.");
     
     codeBlock->alternative()->forceOptimizationSlowPathConcurrently();
 }
@@ -59,8 +58,7 @@
     ASSERT(!profiledDFGCodeBlock);
     ASSERT(codeBlock->alternative()->jitType() == JITType::BaselineJIT);
     
-    if (Options::verboseOSR())
-        dataLog("Optimizing compilation of ", *codeBlock, " result: ", result, "\n");
+    dataLogLnIf(Options::verboseOSR(), "Optimizing compilation of ", *codeBlock, " result: ", result);
     
     if (result == CompilationSuccessful)
         codeBlock->ownerExecutable()->installCode(codeBlock);
diff --git a/Source/JavaScriptCore/jit/JITWorklist.cpp b/Source/JavaScriptCore/jit/JITWorklist.cpp
index c648d46..1980eea 100644
--- a/Source/JavaScriptCore/jit/JITWorklist.cpp
+++ b/Source/JavaScriptCore/jit/JITWorklist.cpp
@@ -57,14 +57,12 @@
         switch (result) {
         case CompilationFailed:
             CODEBLOCK_LOG_EVENT(m_codeBlock, "delayJITCompile", ("compilation failed"));
-            if (Options::verboseOSR())
-                dataLogF("    JIT compilation failed.\n");
+            dataLogLnIf(Options::verboseOSR(), "    JIT compilation failed.");
             m_codeBlock->dontJITAnytimeSoon();
             m_codeBlock->m_didFailJITCompilation = true;
             return;
         case CompilationSuccessful:
-            if (Options::verboseOSR())
-                dataLogF("    JIT compilation successful.\n");
+            dataLogLnIf(Options::verboseOSR(), "    JIT compilation successful.");
             m_codeBlock->ownerExecutable()->installCode(m_codeBlock);
             m_codeBlock->jitSoon();
             return;
diff --git a/Source/JavaScriptCore/jit/PolymorphicCallStubRoutine.cpp b/Source/JavaScriptCore/jit/PolymorphicCallStubRoutine.cpp
index cfa6f98..3fe82f8 100644
--- a/Source/JavaScriptCore/jit/PolymorphicCallStubRoutine.cpp
+++ b/Source/JavaScriptCore/jit/PolymorphicCallStubRoutine.cpp
@@ -45,9 +45,7 @@
 void PolymorphicCallNode::unlink(VM& vm)
 {
     if (m_callLinkInfo) {
-        if (Options::dumpDisassembly())
-            dataLog("Unlinking polymorphic call at ", m_callLinkInfo->callReturnLocation(), ", ", m_callLinkInfo->codeOrigin(), "\n");
-
+        dataLogLnIf(Options::dumpDisassembly(), "Unlinking polymorphic call at ", m_callLinkInfo->callReturnLocation(), ", ", m_callLinkInfo->codeOrigin());
         m_callLinkInfo->unlink(vm);
     }
 
diff --git a/Source/JavaScriptCore/jit/Repatch.cpp b/Source/JavaScriptCore/jit/Repatch.cpp
index 5918883..d13d6d5 100644
--- a/Source/JavaScriptCore/jit/Repatch.cpp
+++ b/Source/JavaScriptCore/jit/Repatch.cpp
@@ -1038,8 +1038,7 @@
 
 void unlinkFor(VM& vm, CallLinkInfo& callLinkInfo)
 {
-    if (Options::dumpDisassembly())
-        dataLog("Unlinking call at ", callLinkInfo.hotPathOther(), "\n");
+    dataLogLnIf(Options::dumpDisassembly(), "Unlinking call at ", callLinkInfo.hotPathOther());
     
     revertCall(vm, callLinkInfo, vm.getCTIStub(linkCallThunkGenerator).retagged<JITStubRoutinePtrTag>());
 }
@@ -1049,8 +1048,8 @@
     CallFrame* callerFrame = callFrame->callerFrame();
     CodeBlock* callerCodeBlock = callerFrame->codeBlock();
 
-    if (shouldDumpDisassemblyFor(callerCodeBlock))
-        dataLog("Linking virtual call at ", FullCodeOrigin(callerCodeBlock, callerFrame->codeOrigin()), "\n");
+    dataLogLnIf(shouldDumpDisassemblyFor(callerCodeBlock),
+        "Linking virtual call at ", FullCodeOrigin(callerCodeBlock, callerFrame->codeOrigin()));
 
     MacroAssemblerCodeRef<JITStubRoutinePtrTag> virtualThunk = virtualThunkFor(vm, callLinkInfo);
     revertCall(vm, callLinkInfo, virtualThunk);
diff --git a/Source/JavaScriptCore/llint/LLIntSlowPaths.cpp b/Source/JavaScriptCore/llint/LLIntSlowPaths.cpp
index ac72abc..83867d1 100644
--- a/Source/JavaScriptCore/llint/LLIntSlowPaths.cpp
+++ b/Source/JavaScriptCore/llint/LLIntSlowPaths.cpp
@@ -378,8 +378,7 @@
 
     if (!codeBlock->checkIfJITThresholdReached()) {
         CODEBLOCK_LOG_EVENT(codeBlock, "delayJITCompile", ("threshold not reached, counter = ", codeBlock->llintExecuteCounter()));
-        if (Options::verboseOSR())
-            dataLogF("    JIT threshold should be lifted.\n");
+        dataLogLnIf(Options::verboseOSR(), "    JIT threshold should be lifted.");
         return false;
     }
     
@@ -387,8 +386,7 @@
     
     switch (codeBlock->jitType()) {
     case JITType::BaselineJIT: {
-        if (Options::verboseOSR())
-            dataLogF("    Code was already compiled.\n");
+        dataLogLnIf(Options::verboseOSR(), "    Code was already compiled.");
         codeBlock->jitSoon();
         return true;
     }
@@ -405,11 +403,9 @@
 
 static SlowPathReturnType entryOSR(CodeBlock* codeBlock, const char *name, EntryKind kind)
 {
-    if (Options::verboseOSR()) {
-        dataLog(
-            *codeBlock, ": Entered ", name, " with executeCounter = ",
-            codeBlock->llintExecuteCounter(), "\n");
-    }
+    dataLogLnIf(Options::verboseOSR(),
+        *codeBlock, ": Entered ", name, " with executeCounter = ",
+        codeBlock->llintExecuteCounter());
     
     if (!shouldJIT(codeBlock)) {
         codeBlock->dontJITAnytimeSoon();
@@ -471,11 +467,9 @@
     UNUSED_PARAM(globalObject);
 
 #if ENABLE(JIT)
-    if (Options::verboseOSR()) {
-        dataLog(
+    dataLogLnIf(Options::verboseOSR(),
             *codeBlock, ": Entered loop_osr with executeCounter = ",
-            codeBlock->llintExecuteCounter(), "\n");
-    }
+            codeBlock->llintExecuteCounter());
     
     auto loopOSREntryBytecodeIndex = BytecodeIndex(codeBlock->bytecodeOffset(pc));
 
@@ -513,11 +507,9 @@
     UNUSED_PARAM(globalObject);
 
 #if ENABLE(JIT)
-    if (Options::verboseOSR()) {
-        dataLog(
-            *codeBlock, ": Entered replace with executeCounter = ",
-            codeBlock->llintExecuteCounter(), "\n");
-    }
+    dataLogLnIf(Options::verboseOSR(),
+        *codeBlock, ": Entered replace with executeCounter = ",
+        codeBlock->llintExecuteCounter());
     
     if (shouldJIT(codeBlock))
         jitCompileAndSetHeuristics(vm, codeBlock);
diff --git a/Source/JavaScriptCore/parser/ModuleAnalyzer.cpp b/Source/JavaScriptCore/parser/ModuleAnalyzer.cpp
index 02855d3..0736999 100644
--- a/Source/JavaScriptCore/parser/ModuleAnalyzer.cpp
+++ b/Source/JavaScriptCore/parser/ModuleAnalyzer.cpp
@@ -140,7 +140,7 @@
     for (const auto& pair : m_moduleRecord->lexicalVariables())
         exportVariable(moduleProgramNode, pair.key, pair.value);
 
-    if (Options::dumpModuleRecord())
+    if (UNLIKELY(Options::dumpModuleRecord()))
         m_moduleRecord->dump();
 
     return m_moduleRecord.get();
diff --git a/Source/JavaScriptCore/runtime/JSModuleLoader.cpp b/Source/JavaScriptCore/runtime/JSModuleLoader.cpp
index 64dd3e6..4a1a91f 100644
--- a/Source/JavaScriptCore/runtime/JSModuleLoader.cpp
+++ b/Source/JavaScriptCore/runtime/JSModuleLoader.cpp
@@ -252,8 +252,7 @@
 
 JSInternalPromise* JSModuleLoader::importModule(JSGlobalObject* globalObject, JSString* moduleName, JSValue parameters, const SourceOrigin& referrer)
 {
-    if (Options::dumpModuleLoadingState())
-        dataLog("Loader [import] ", printableModuleKey(globalObject, moduleName), "\n");
+    dataLogLnIf(Options::dumpModuleLoadingState(), "Loader [import] ", printableModuleKey(globalObject, moduleName));
 
     VM& vm = globalObject->vm();
     auto throwScope = DECLARE_THROW_SCOPE(vm);
@@ -279,8 +278,7 @@
 
 Identifier JSModuleLoader::resolveSync(JSGlobalObject* globalObject, JSValue name, JSValue referrer, JSValue scriptFetcher)
 {
-    if (Options::dumpModuleLoadingState())
-        dataLog("Loader [resolve] ", printableModuleKey(globalObject, name), "\n");
+    dataLogLnIf(Options::dumpModuleLoadingState(), "Loader [resolve] ", printableModuleKey(globalObject, name));
 
     if (globalObject->globalObjectMethodTable()->moduleLoaderResolve)
         return globalObject->globalObjectMethodTable()->moduleLoaderResolve(globalObject, this, name, referrer, scriptFetcher);
@@ -310,8 +308,7 @@
 
 JSInternalPromise* JSModuleLoader::fetch(JSGlobalObject* globalObject, JSValue key, JSValue parameters, JSValue scriptFetcher)
 {
-    if (Options::dumpModuleLoadingState())
-        dataLog("Loader [fetch] ", printableModuleKey(globalObject, key), "\n");
+    dataLogLnIf(Options::dumpModuleLoadingState(), "Loader [fetch] ", printableModuleKey(globalObject, key));
 
     VM& vm = globalObject->vm();
     auto throwScope = DECLARE_THROW_SCOPE(vm);
@@ -345,8 +342,7 @@
 
 JSValue JSModuleLoader::evaluate(JSGlobalObject* globalObject, JSValue key, JSValue moduleRecordValue, JSValue scriptFetcher)
 {
-    if (Options::dumpModuleLoadingState())
-        dataLog("Loader [evaluate] ", printableModuleKey(globalObject, key), "\n");
+    dataLogLnIf(Options::dumpModuleLoadingState(), "Loader [evaluate] ", printableModuleKey(globalObject, key));
 
     if (globalObject->globalObjectMethodTable()->moduleLoaderEvaluate)
         return globalObject->globalObjectMethodTable()->moduleLoaderEvaluate(globalObject, this, key, moduleRecordValue, scriptFetcher);
@@ -449,8 +445,7 @@
     if (!moduleRecord)
         return JSValue::encode(jsUndefined());
 
-    if (Options::dumpModuleLoadingState())
-        dataLog("Loader [link] ", moduleRecord->moduleKey(), "\n");
+    dataLogLnIf(Options::dumpModuleLoadingState(), "Loader [link] ", moduleRecord->moduleKey());
 
     moduleRecord->link(globalObject, callFrame->argument(1));
     RETURN_IF_EXCEPTION(scope, encodedJSValue());
diff --git a/Source/JavaScriptCore/runtime/ScriptExecutable.cpp b/Source/JavaScriptCore/runtime/ScriptExecutable.cpp
index ff84202..7543694 100644
--- a/Source/JavaScriptCore/runtime/ScriptExecutable.cpp
+++ b/Source/JavaScriptCore/runtime/ScriptExecutable.cpp
@@ -196,8 +196,7 @@
         RELEASE_ASSERT(genericCodeBlock->ownerExecutable() == this);
         RELEASE_ASSERT(JITCode::isExecutableScript(genericCodeBlock->jitType()));
         
-        if (UNLIKELY(Options::verboseOSR()))
-            dataLog("Installing ", *genericCodeBlock, "\n");
+        dataLogLnIf(Options::verboseOSR(), "Installing ", *genericCodeBlock);
         
         if (UNLIKELY(vm.m_perBytecodeProfiler))
             vm.m_perBytecodeProfiler->ensureBytecodesFor(genericCodeBlock);
diff --git a/Source/JavaScriptCore/runtime/VM.cpp b/Source/JavaScriptCore/runtime/VM.cpp
index a9fe74a..8803a71 100644
--- a/Source/JavaScriptCore/runtime/VM.cpp
+++ b/Source/JavaScriptCore/runtime/VM.cpp
@@ -938,7 +938,7 @@
     if (!throwOriginFrame)
         throwOriginFrame = globalObject->deprecatedCallFrameForDebugger();
 
-    if (Options::breakOnThrow()) {
+    if (UNLIKELY(Options::breakOnThrow())) {
         CodeBlock* codeBlock = throwOriginFrame ? throwOriginFrame->codeBlock() : nullptr;
         dataLog("Throwing exception in call frame ", RawPointer(throwOriginFrame), " for code block ", codeBlock, "\n");
         CRASH();
diff --git a/Source/JavaScriptCore/tools/CompilerTimingScope.cpp b/Source/JavaScriptCore/tools/CompilerTimingScope.cpp
index 96f0dae..524a85e 100644
--- a/Source/JavaScriptCore/tools/CompilerTimingScope.cpp
+++ b/Source/JavaScriptCore/tools/CompilerTimingScope.cpp
@@ -64,13 +64,13 @@
     : m_compilerName(compilerName)
     , m_name(name)
 {
-    if (Options::logPhaseTimes())
+    if (UNLIKELY(Options::logPhaseTimes()))
         m_before = MonotonicTime::now();
 }
 
 CompilerTimingScope::~CompilerTimingScope()
 {
-    if (Options::logPhaseTimes()) {
+    if (UNLIKELY(Options::logPhaseTimes())) {
         Seconds duration = MonotonicTime::now() - m_before;
         dataLog(
             "[", m_compilerName, "] ", m_name, " took: ", duration.milliseconds(), " ms ",
diff --git a/Source/JavaScriptCore/wasm/WasmMemory.cpp b/Source/JavaScriptCore/wasm/WasmMemory.cpp
index fdeab94..e407269 100644
--- a/Source/JavaScriptCore/wasm/WasmMemory.cpp
+++ b/Source/JavaScriptCore/wasm/WasmMemory.cpp
@@ -120,8 +120,7 @@
                 m_fastMemories.size() >= m_maxFastMemoryCount / 2 ? MemoryResult::SuccessAndNotifyMemoryPressure : MemoryResult::Success);
         }();
         
-        if (Options::logWebAssemblyMemory())
-            dataLog("Allocated virtual: ", result, "; state: ", *this, "\n");
+        dataLogLnIf(Options::logWebAssemblyMemory(), "Allocated virtual: ", result, "; state: ", *this);
         
         return result;
     }
@@ -134,8 +133,7 @@
             m_fastMemories.removeFirst(basePtr);
         }
         
-        if (Options::logWebAssemblyMemory())
-            dataLog("Freed virtual; state: ", *this, "\n");
+        dataLogLnIf(Options::logWebAssemblyMemory(), "Freed virtual; state: ", *this);
     }
     
     bool isAddressInFastMemory(void* address)
@@ -172,8 +170,7 @@
             return MemoryResult::Success;
         }();
         
-        if (Options::logWebAssemblyMemory())
-            dataLog("Allocated physical: ", bytes, ", ", MemoryResult::toString(result), "; state: ", *this, "\n");
+        dataLogLnIf(Options::logWebAssemblyMemory(), "Allocated physical: ", bytes, ", ", MemoryResult::toString(result), "; state: ", *this);
         
         return result;
     }
@@ -185,8 +182,7 @@
             m_physicalBytes -= bytes;
         }
         
-        if (Options::logWebAssemblyMemory())
-            dataLog("Freed physical: ", bytes, "; state: ", *this, "\n");
+        dataLogLnIf(Options::logWebAssemblyMemory(), "Freed physical: ", bytes, "; state: ", *this);
     }
     
     void dump(PrintStream& out) const
diff --git a/Source/JavaScriptCore/wasm/js/JSWebAssembly.cpp b/Source/JavaScriptCore/wasm/js/JSWebAssembly.cpp
index 3649e57..d53ab26 100644
--- a/Source/JavaScriptCore/wasm/js/JSWebAssembly.cpp
+++ b/Source/JavaScriptCore/wasm/js/JSWebAssembly.cpp
@@ -190,7 +190,7 @@
         promise->resolve(globalObject, instance);
     else if (resolveKind == Resolve::WithModuleRecord) {
         auto* moduleRecord = instance->moduleNamespaceObject()->moduleRecord();
-        if (Options::dumpModuleRecord())
+        if (UNLIKELY(Options::dumpModuleRecord()))
             moduleRecord->dump();
         promise->resolve(globalObject, moduleRecord);
     } else {
diff --git a/Source/JavaScriptCore/yarr/YarrJIT.cpp b/Source/JavaScriptCore/yarr/YarrJIT.cpp
index 412a811..d2f0e8e 100644
--- a/Source/JavaScriptCore/yarr/YarrJIT.cpp
+++ b/Source/JavaScriptCore/yarr/YarrJIT.cpp
@@ -4243,7 +4243,7 @@
         YarrGenerator<IncludeSubpatterns>(vm, pattern, patternString, codeBlock, charSize).compile();
 
     if (auto failureReason = codeBlock.failureReason()) {
-        if (Options::dumpCompiledRegExpPatterns()) {
+        if (UNLIKELY(Options::dumpCompiledRegExpPatterns())) {
             pattern.dumpPatternString(WTF::dataFile(), patternString);
             dataLog(" : ");
             dumpCompileFailure(*failureReason);
diff --git a/Source/JavaScriptCore/yarr/YarrPattern.cpp b/Source/JavaScriptCore/yarr/YarrPattern.cpp
index eb60dbe..c508208 100644
--- a/Source/JavaScriptCore/yarr/YarrPattern.cpp
+++ b/Source/JavaScriptCore/yarr/YarrPattern.cpp
@@ -1177,7 +1177,7 @@
             return error;
     }
 
-    if (Options::dumpCompiledRegExpPatterns())
+    if (UNLIKELY(Options::dumpCompiledRegExpPatterns()))
         dumpPattern(patternString);
 
     return ErrorCode::NoError;
diff --git a/Source/WTF/ChangeLog b/Source/WTF/ChangeLog
index f36d657..e4183e4 100644
--- a/Source/WTF/ChangeLog
+++ b/Source/WTF/ChangeLog
@@ -1,3 +1,14 @@
+2020-01-16  Robin Morisset  <rmorisset@apple.com>
+
+        Use dataLogIf more regularly
+        https://bugs.webkit.org/show_bug.cgi?id=206332
+
+        Reviewed by Keith Miller.
+
+        * wtf/DataLog.h:
+        (WTF::dataLog): Marked NEVER_INLINE, since it should never be perf-sensitive
+
+
 2020-01-16  Sam Weinig  <weinig@apple.com>
 
         Platform.h is out of control Part 6: Split USE_* macro definitions out of Platform.h and into a new PlatformUse.h
diff --git a/Source/WTF/wtf/DataLog.h b/Source/WTF/wtf/DataLog.h
index 0b844b5..9e3c766 100644
--- a/Source/WTF/wtf/DataLog.h
+++ b/Source/WTF/wtf/DataLog.h
@@ -40,7 +40,7 @@
 WTF_EXPORT_PRIVATE void dataLogFString(const char*);
 
 template<typename... Types>
-void dataLog(const Types&... values)
+NEVER_INLINE void dataLog(const Types&... values)
 {
     dataFile().print(values...);
 }