V8 Options

 SSE3=1 SSSE3=1 SSE4_1=1 SSE4_2=1 SAHF=1 AVX=1 FMA3=1 BMI1=1 BMI2=1 LZCNT=1 POPCNT=1 ATOM=0

Synopsis:

  shell [options] [--shell] [<file>...]

  d8 [options] [-e <string>] [--shell] [[--module] <file>...]

  -e        execute a string in V8

  --shell   run an interactive JavaScript shell

  --module  execute a file as a JavaScript module

Note: the --module option is implicitly enabled for *.mjs files.

The following syntax for options is accepted (both '-' and '--' are ok):

  --flag        (bool flags only)

  --no-flag     (bool flags only)

  --flag=value  (non-bool flags only, no spaces around '=')

  --flag value  (non-bool flags only)

  --            (captures all remaining args in JavaScript)

Options:

  --use-strict (enforce strict mode)

        type: bool  default: false

  --es-staging (enable test-worthy harmony features (for internal use only))

        type: bool  default: false

  --harmony (enable all completed harmony features)

        type: bool  default: false

  --harmony-shipping (enable all shipped harmony features)

        type: bool  default: true

  --harmony-regexp-sequence (enable "RegExp Unicode sequence properties" (in progress))

        type: bool  default: false

  --harmony-weak-refs-with-cleanup-some (enable "harmony weak references with FinalizationRegistry.prototype.cleanupSome" (in progress))

        type: bool  default: false

  --harmony-regexp-match-indices (enable "harmony regexp match indices" (in progress))

        type: bool  default: false

  --harmony-intl-displaynames-date-types (enable "Intl.DisplayNames date types" (in progress))

        type: bool  default: false

  --harmony-string-replaceall (enable "harmony String.prototype.replaceAll")

        type: bool  default: false

  --harmony-logical-assignment (enable "harmony logical assignment")

        type: bool  default: false

  --harmony-promise-any (enable "harmony Promise.any")

        type: bool  default: false

  --harmony-top-level-await (enable "harmony top level await")

        type: bool  default: true

  --harmony-intl-dateformat-day-period (enable "Add dayPeriod option to DateTimeFormat")

        type: bool  default: false

  --harmony-intl-segmenter (enable "Intl.Segmenter")

        type: bool  default: false

  --harmony-namespace-exports (enable "harmony namespace exports (export * as foo from 'bar')")

        type: bool  default: true

  --harmony-sharedarraybuffer (enable "harmony sharedarraybuffer")

        type: bool  default: true

  --harmony-import-meta (enable "harmony import.meta property")

        type: bool  default: true

  --harmony-dynamic-import (enable "harmony dynamic import")

        type: bool  default: true

  --harmony-promise-all-settled (enable "harmony Promise.allSettled")

        type: bool  default: true

  --harmony-private-methods (enable "harmony private methods in class literals")

        type: bool  default: true

  --harmony-weak-refs (enable "harmony weak references")

        type: bool  default: true

  --harmony-intl-dateformat-fractional-second-digits (enable "Add fractionalSecondDigits option to DateTimeFormat")

        type: bool  default: true

  --icu-timezone-data (get information about timezones from ICU)

        type: bool  default: true

  --lite-mode (enables trade-off of performance for memory savings)

        type: bool  default: false

  --future (Implies all staged features that we want to ship in the not-too-far future)

        type: bool  default: false

  --assert-types (generate runtime type assertions to test the typer)

        type: bool  default: false

  --allocation-site-pretenuring (pretenure with allocation sites)

        type: bool  default: true

  --page-promotion (promote pages based on utilization)

        type: bool  default: true

  --always-promote-young-mc (always promote young objects during mark-compact)

        type: bool  default: true

  --page-promotion-threshold (min percentage of live bytes on a page to enable fast evacuation)

        type: int  default: 70

  --trace-pretenuring (trace pretenuring decisions of HAllocate instructions)

        type: bool  default: false

  --trace-pretenuring-statistics (trace allocation site pretenuring statistics)

        type: bool  default: false

  --track-fields (track fields with only smi values)

        type: bool  default: true

  --track-double-fields (track fields with double values)

        type: bool  default: true

  --track-heap-object-fields (track fields with heap values)

        type: bool  default: true

  --track-computed-fields (track computed boilerplate fields)

        type: bool  default: true

  --track-field-types (track field types)

        type: bool  default: true

  --trace-block-coverage (trace collected block coverage information)

        type: bool  default: false

  --trace-protector-invalidation (trace protector cell invalidations)

        type: bool  default: false

  --feedback-normalization (feed back normalization to constructors)

        type: bool  default: false

  --enable-one-shot-optimization (Enable size optimizations for the code that will only be executed once)

        type: bool  default: false

  --unbox-double-arrays (automatically unbox arrays of doubles)

        type: bool  default: true

  --interrupt-budget (interrupt budget which should be used for the profiler counter)

        type: int  default: 147456

  --jitless (Disable runtime allocation of executable memory.)

        type: bool  default: false

  --use-ic (use inline caching)

        type: bool  default: true

  --budget-for-feedback-vector-allocation (The budget in amount of bytecode executed by a function before we decide to allocate feedback vectors)

        type: int  default: 1024

  --lazy-feedback-allocation (Allocate feedback vectors lazily)

        type: bool  default: true

  --ignition-elide-noneffectful-bytecodes (elide bytecodes which won't have any external effect)

        type: bool  default: true

  --ignition-reo (use ignition register equivalence optimizer)

        type: bool  default: true

  --ignition-filter-expression-positions (filter expression positions before the bytecode pipeline)

        type: bool  default: true

  --ignition-share-named-property-feedback (share feedback slots when loading the same named property from the same object)

        type: bool  default: true

  --print-bytecode (print bytecode generated by ignition interpreter)

        type: bool  default: false

  --enable-lazy-source-positions (skip generating source positions during initial compile but regenerate when actually required)

        type: bool  default: true

  --stress-lazy-source-positions (collect lazy source positions immediately after lazy compile)

        type: bool  default: false

  --print-bytecode-filter (filter for selecting which functions to print bytecode)

        type: string  default: *

  --trace-ignition-codegen (trace the codegen of ignition interpreter bytecode handlers)

        type: bool  default: false

  --trace-ignition-dispatches (traces the dispatches to bytecode handlers by the ignition interpreter)

        type: bool  default: false

  --trace-ignition-dispatches-output-file (the file to which the bytecode handler dispatch table is written (by default, the table is not written to a file))

        type: string  default: nullptr

  --fast-math (faster (but maybe less accurate) math functions)

        type: bool  default: true

  --trace-track-allocation-sites (trace the tracking of allocation sites)

        type: bool  default: false

  --trace-migration (trace object migration)

        type: bool  default: false

  --trace-generalization (trace map generalization)

        type: bool  default: false

  --turboprop (enable experimental turboprop mid-tier compiler.)

        type: bool  default: false

  --concurrent-recompilation (optimizing hot functions asynchronously on a separate thread)

        type: bool  default: true

  --trace-concurrent-recompilation (track concurrent recompilation)

        type: bool  default: false

  --concurrent-recompilation-queue-length (the length of the concurrent compilation queue)

        type: int  default: 8

  --concurrent-recompilation-delay (artificial compilation delay in ms)

        type: int  default: 0

  --block-concurrent-recompilation (block queued jobs until released)

        type: bool  default: false

  --concurrent-inlining (run optimizing compiler's inlining phase on a separate thread)

        type: bool  default: false

  --max-serializer-nesting (maximum levels for nesting child serializers)

        type: int  default: 25

  --trace-heap-broker-verbose (trace the heap broker verbosely (all reports))

        type: bool  default: false

  --trace-heap-broker-memory (trace the heap broker memory (refs analysis and zone numbers))

        type: bool  default: false

  --trace-heap-broker (trace the heap broker (reports on missing data only))

        type: bool  default: false

  --stress-runs (number of stress runs)

        type: int  default: 0

  --deopt-every-n-times (deoptimize every n times a deopt point is passed)

        type: int  default: 0

  --print-deopt-stress (print number of possible deopt points)

        type: bool  default: false

  --opt (use adaptive optimizations)

        type: bool  default: true

  --turbo-sp-frame-access (use stack pointer-relative access to frame wherever possible)

        type: bool  default: false

  --turbo-control-flow-aware-allocation (consider control flow while allocating registers)

        type: bool  default: true

  --turbo-filter (optimization filter for TurboFan compiler)

        type: string  default: *

  --trace-turbo (trace generated TurboFan IR)

        type: bool  default: false

  --trace-turbo-path (directory to dump generated TurboFan IR to)

        type: string  default: nullptr

  --trace-turbo-filter (filter for tracing turbofan compilation)

        type: string  default: *

  --trace-turbo-graph (trace generated TurboFan graphs)

        type: bool  default: false

  --trace-turbo-scheduled (trace TurboFan IR with schedule)

        type: bool  default: false

  --trace-turbo-cfg-file (trace turbo cfg graph (for C1 visualizer) to a given file name)

        type: string  default: nullptr

  --trace-turbo-types (trace TurboFan's types)

        type: bool  default: true

  --trace-turbo-scheduler (trace TurboFan's scheduler)

        type: bool  default: false

  --trace-turbo-reduction (trace TurboFan's various reducers)

        type: bool  default: false

  --trace-turbo-trimming (trace TurboFan's graph trimmer)

        type: bool  default: false

  --trace-turbo-jt (trace TurboFan's jump threading)

        type: bool  default: false

  --trace-turbo-ceq (trace TurboFan's control equivalence)

        type: bool  default: false

  --trace-turbo-loop (trace TurboFan's loop optimizations)

        type: bool  default: false

  --trace-turbo-alloc (trace TurboFan's register allocator)

        type: bool  default: false

  --trace-all-uses (trace all use positions)

        type: bool  default: false

  --trace-representation (trace representation types)

        type: bool  default: false

  --turbo-verify (verify TurboFan graphs at each phase)

        type: bool  default: false

  --turbo-verify-machine-graph (verify TurboFan machine graph before instruction selection)

        type: string  default: nullptr

  --trace-verify-csa (trace code stubs verification)

        type: bool  default: false

  --csa-trap-on-node (trigger break point when a node with given id is created in given stub. The format is: StubName,NodeId)

        type: string  default: nullptr

  --turbo-stats (print TurboFan statistics)

        type: bool  default: false

  --turbo-stats-nvp (print TurboFan statistics in machine-readable format)

        type: bool  default: false

  --turbo-stats-wasm (print TurboFan statistics of wasm compilations)

        type: bool  default: false

  --turbo-splitting (split nodes during scheduling in TurboFan)

        type: bool  default: true

  --function-context-specialization (enable function context specialization in TurboFan)

        type: bool  default: false

  --turbo-inlining (enable inlining in TurboFan)

        type: bool  default: true

  --max-inlined-bytecode-size (maximum size of bytecode for a single inlining)

        type: int  default: 500

  --max-inlined-bytecode-size-cumulative (maximum cumulative size of bytecode considered for inlining)

        type: int  default: 1000

  --max-inlined-bytecode-size-absolute (maximum cumulative size of bytecode considered for inlining)

        type: int  default: 5000

  --reserve-inline-budget-scale-factor (maximum cumulative size of bytecode considered for inlining)

        type: float  default: 1.2

  --max-inlined-bytecode-size-small (maximum size of bytecode considered for small function inlining)

        type: int  default: 30

  --max-optimized-bytecode-size (maximum bytecode size to be considered for optimization; too high values may cause the compiler to hit (release) assertions)

        type: int  default: 61440

  --min-inlining-frequency (minimum frequency for inlining)

        type: float  default: 0.15

  --polymorphic-inlining (polymorphic inlining)

        type: bool  default: true

  --stress-inline (set high thresholds for inlining to inline as much as possible)

        type: bool  default: false

  --trace-turbo-inlining (trace TurboFan inlining)

        type: bool  default: false

  --turbo-inline-array-builtins (inline array builtins in TurboFan code)

        type: bool  default: true

  --use-osr (use on-stack replacement)

        type: bool  default: true

  --trace-osr (trace on-stack replacement)

        type: bool  default: false

  --analyze-environment-liveness (analyze liveness of environment slots and zap dead values)

        type: bool  default: true

  --trace-environment-liveness (trace liveness of local variable slots)

        type: bool  default: false

  --turbo-load-elimination (enable load elimination in TurboFan)

        type: bool  default: true

  --trace-turbo-load-elimination (trace TurboFan load elimination)

        type: bool  default: false

  --turbo-profiling (enable profiling in TurboFan)

        type: bool  default: false

  --turbo-verify-allocation (verify register allocation in TurboFan)

        type: bool  default: false

  --turbo-move-optimization (optimize gap moves in TurboFan)

        type: bool  default: true

  --turbo-jt (enable jump threading in TurboFan)

        type: bool  default: true

  --turbo-loop-peeling (Turbofan loop peeling)

        type: bool  default: true

  --turbo-loop-variable (Turbofan loop variable optimization)

        type: bool  default: true

  --turbo-loop-rotation (Turbofan loop rotation)

        type: bool  default: true

  --turbo-cf-optimization (optimize control flow in TurboFan)

        type: bool  default: true

  --turbo-escape (enable escape analysis)

        type: bool  default: true

  --turbo-allocation-folding (Turbofan allocation folding)

        type: bool  default: true

  --turbo-instruction-scheduling (enable instruction scheduling in TurboFan)

        type: bool  default: false

  --turbo-stress-instruction-scheduling (randomly schedule instructions to stress dependency tracking)

        type: bool  default: false

  --turbo-store-elimination (enable store-store elimination in TurboFan)

        type: bool  default: true

  --trace-store-elimination (trace store elimination)

        type: bool  default: false

  --turbo-rewrite-far-jumps (rewrite far to near jumps (ia32,x64))

        type: bool  default: true

  --stress-gc-during-compilation (simulate GC/compiler thread race related to https://crbug.com/v8/8520)

        type: bool  default: false

  --turbo-fast-api-calls (enable fast API calls from TurboFan)

        type: bool  default: false

  --reuse-opt-code-count (don't discard optimized code for the specified number of deopts.)

        type: int  default: 0

  --turbo-nci (enable experimental native context independent code.)

        type: bool  default: false

  --turbo-nci-as-highest-tier (replace default TF with NCI code as the highest tier for testing purposes.)

        type: bool  default: false

  --print-nci-code (print native context independent code.)

        type: bool  default: false

  --trace-turbo-nci (trace native context independent code.)

        type: bool  default: false

  --optimize-for-size (Enables optimizations which favor memory size over execution speed)

        type: bool  default: false

  --untrusted-code-mitigations (Enable mitigations for executing untrusted code)

        type: bool  default: false

  --expose-wasm (expose wasm interface to JavaScript)

        type: bool  default: true

  --assume-asmjs-origin (force wasm decoder to assume input is internal asm-wasm format)

        type: bool  default: false

  --wasm-num-compilation-tasks (maximum number of parallel compilation tasks for wasm)

        type: int  default: 128

  --wasm-write-protect-code-memory (write protect code memory on the wasm native heap)

        type: bool  default: false

  --wasm-async-compilation (enable actual asynchronous compilation for WebAssembly.compile)

        type: bool  default: true

  --wasm-test-streaming (use streaming compilation instead of async compilation for tests)

        type: bool  default: false

  --wasm-max-mem-pages (maximum initial number of 64KiB memory pages of a wasm instance)

        type: uint  default: 32767

  --wasm-max-mem-pages-growth (maximum number of 64KiB pages a Wasm memory can grow to)

        type: uint  default: 65536

  --wasm-max-table-size (maximum table size of a wasm instance)

        type: uint  default: 10000000

  --wasm-max-code-space (maximum committed code space for wasm (in MB))

        type: uint  default: 1024

  --wasm-tier-up (enable tier up to the optimizing compiler (requires --liftoff to have an effect))

        type: bool  default: true

  --trace-wasm-ast-start (start function for wasm AST trace (inclusive))

        type: int  default: 0

  --trace-wasm-ast-end (end function for wasm AST trace (exclusive))

        type: int  default: 0

  --liftoff (enable Liftoff, the baseline compiler for WebAssembly)

        type: bool  default: true

  --trace-wasm-memory (print all memory updates performed in wasm code)

        type: bool  default: false

  --wasm-tier-mask-for-testing (bitmask of functions to compile with TurboFan instead of Liftoff)

        type: int  default: 0

  --wasm-expose-debug-eval (Expose wasm evaluator support on the CDP)

        type: bool  default: false

  --validate-asm (validate asm.js modules before compiling)

        type: bool  default: true

  --suppress-asm-messages (don't emit asm.js related messages (for golden file testing))

        type: bool  default: false

  --trace-asm-time (log asm.js timing info to the console)

        type: bool  default: false

  --trace-asm-scanner (log tokens encountered by asm.js scanner)

        type: bool  default: false

  --trace-asm-parser (verbose logging of asm.js parse failures)

        type: bool  default: false

  --stress-validate-asm (try to validate everything as asm.js)

        type: bool  default: false

  --dump-wasm-module-path (directory to dump wasm modules to)

        type: string  default: nullptr

  --experimental-wasm-eh (enable prototype exception handling opcodes for wasm)

        type: bool  default: false

  --experimental-wasm-simd (enable prototype SIMD opcodes for wasm)

        type: bool  default: false

  --experimental-wasm-return-call (enable prototype return call opcodes for wasm)

        type: bool  default: false

  --experimental-wasm-compilation-hints (enable prototype compilation hints section for wasm)

        type: bool  default: false

  --experimental-wasm-gc (enable prototype garbage collection for wasm)

        type: bool  default: false

  --experimental-wasm-anyref (enable prototype anyref opcodes for wasm)

        type: bool  default: false

  --experimental-wasm-bigint (enable prototype JS BigInt support for wasm)

        type: bool  default: false

  --experimental-wasm-mv (enable prototype multi-value support for wasm)

        type: bool  default: false

  --experimental-wasm-threads (enable prototype thread opcodes for wasm)

        type: bool  default: false

  --experimental-wasm-type-reflection (enable prototype wasm type reflection in JS for wasm)

        type: bool  default: false

  --experimental-wasm-bulk-memory (enable prototype bulk memory opcodes for wasm)

        type: bool  default: true

  --wasm-staging (enable staged wasm features)

        type: bool  default: false

  --wasm-opt (enable wasm optimization)

        type: bool  default: false

  --wasm-bounds-checks (enable bounds checks (disable for performance testing only))

        type: bool  default: true

  --wasm-stack-checks (enable stack checks (disable for performance testing only))

        type: bool  default: true

  --wasm-math-intrinsics (intrinsify some Math imports into wasm)

        type: bool  default: true

  --wasm-trap-handler (use signal handlers to catch out of bounds memory access in wasm (currently Linux x86_64 only))

        type: bool  default: true

  --wasm-fuzzer-gen-test (generate a test case when running a wasm fuzzer)

        type: bool  default: false

  --print-wasm-code (Print WebAssembly code)

        type: bool  default: false

  --print-wasm-stub-code (Print WebAssembly stub code)

        type: bool  default: false

  --asm-wasm-lazy-compilation (enable lazy compilation for asm-wasm modules)

        type: bool  default: false

  --wasm-lazy-compilation (enable lazy compilation for all wasm modules)

        type: bool  default: false

  --wasm-lazy-validation (enable lazy validation for lazily compiled wasm functions)

        type: bool  default: false

  --wasm-atomics-on-non-shared-memory (allow atomic operations on non-shared WebAssembly memory)

        type: bool  default: false

  --wasm-grow-shared-memory (allow growing shared WebAssembly memory objects)

        type: bool  default: true

  --wasm-simd-post-mvp (allow experimental SIMD operations for prototyping that are not included in the current proposal)

        type: bool  default: false

  --wasm-code-gc (enable garbage collection of wasm code)

        type: bool  default: true

  --trace-wasm-code-gc (trace garbage collection of wasm code)

        type: bool  default: false

  --stress-wasm-code-gc (stress test garbage collection of wasm code)

        type: bool  default: false

  --wasm-max-initial-code-space-reservation (maximum size of the initial wasm code space reservation (in MB))

        type: int  default: 0

  --frame-count (number of stack frames inspected by the profiler)

        type: int  default: 1

  --stress-sampling-allocation-profiler (Enables sampling allocation profiler with X as a sample interval)

        type: int  default: 0

  --min-semi-space-size (min size of a semi-space (in MBytes), the new space consists of two semi-spaces)

        type: size_t  default: 0

  --max-semi-space-size (max size of a semi-space (in MBytes), the new space consists of two semi-spaces)

        type: size_t  default: 0

  --semi-space-growth-factor (factor by which to grow the new space)

        type: int  default: 2

  --max-old-space-size (max size of the old space (in Mbytes))

        type: size_t  default: 0

  --max-heap-size (max size of the heap (in Mbytes) both max_semi_space_size and max_old_space_size take precedence. All three flags cannot be specified at the same time.)

        type: size_t  default: 0

  --initial-heap-size (initial size of the heap (in Mbytes))

        type: size_t  default: 0

  --huge-max-old-generation-size (Increase max size of the old space to 4 GB for x64 systems withthe physical memory bigger than 16 GB)

        type: bool  default: true

  --initial-old-space-size (initial old space size (in Mbytes))

        type: size_t  default: 0

  --global-gc-scheduling (enable GC scheduling based on global memory)

        type: bool  default: true

  --gc-global (always perform global GCs)

        type: bool  default: false

  --random-gc-interval (Collect garbage after random(0, X) allocations. It overrides gc_interval.)

        type: int  default: 0

  --gc-interval (garbage collect after <n> allocations)

        type: int  default: -1

  --retain-maps-for-n-gc (keeps maps alive for <n> old space garbage collections)

        type: int  default: 2

  --trace-gc (print one trace line following each garbage collection)

        type: bool  default: false

  --trace-gc-nvp (print one detailed trace line in name=value format after each garbage collection)

        type: bool  default: false

  --trace-gc-ignore-scavenger (do not print trace line after scavenger collection)

        type: bool  default: false

  --trace-idle-notification (print one trace line following each idle notification)

        type: bool  default: false

  --trace-idle-notification-verbose (prints the heap state used by the idle notification)

        type: bool  default: false

  --trace-gc-verbose (print more details following each garbage collection)

        type: bool  default: false

  --trace-gc-freelists (prints details of each freelist before and after each major garbage collection)

        type: bool  default: false

  --trace-gc-freelists-verbose (prints details of freelists of each page before and after each major garbage collection)

        type: bool  default: false

  --trace-evacuation-candidates (Show statistics about the pages evacuation by the compaction)

        type: bool  default: false

  --trace-allocations-origins (Show statistics about the origins of allocations. Combine with --no-inline-new to track allocations from generated code)

        type: bool  default: false

  --gc-freelist-strategy (Freelist strategy to use: 0:FreeListLegacy. 1:FreeListFastAlloc. 2:FreeListMany. 3:FreeListManyCached. 4:FreeListManyCachedFastPath. 5:FreeListManyCachedOrigin. )

        type: int  default: 5

  --trace-allocation-stack-interval (print stack trace after <n> free-list allocations)

        type: int  default: -1

  --trace-duplicate-threshold-kb (print duplicate objects in the heap if their size is more than given threshold)

        type: int  default: 0

  --trace-fragmentation (report fragmentation for old space)

        type: bool  default: false

  --trace-fragmentation-verbose (report fragmentation for old space (detailed))

        type: bool  default: false

  --trace-evacuation (report evacuation statistics)

        type: bool  default: false

  --trace-mutator-utilization (print mutator utilization, allocation speed, gc speed)

        type: bool  default: false

  --incremental-marking (use incremental marking)

        type: bool  default: true

  --incremental-marking-wrappers (use incremental marking for marking wrappers)

        type: bool  default: true

  --incremental-marking-task (use tasks for incremental marking)

        type: bool  default: true

  --incremental-marking-soft-trigger (threshold for starting incremental marking via a task in percent of available space: limit - size)

        type: int  default: 0

  --incremental-marking-hard-trigger (threshold for starting incremental marking immediately in percent of available space: limit - size)

        type: int  default: 0

  --trace-unmapper (Trace the unmapping)

        type: bool  default: false

  --parallel-scavenge (parallel scavenge)

        type: bool  default: true

  --scavenge-task (schedule scavenge tasks)

        type: bool  default: true

  --scavenge-task-trigger (scavenge task trigger in percent of the current heap limit)

        type: int  default: 80

  --scavenge-separate-stack-scanning (use a separate phase for stack scanning in scavenge)

        type: bool  default: true

  --trace-parallel-scavenge (trace parallel scavenge)

        type: bool  default: false

  --write-protect-code-memory (write protect code memory)

        type: bool  default: true

  --concurrent-marking (use concurrent marking)

        type: bool  default: true

  --concurrent-array-buffer-sweeping (concurrently sweep array buffers)

        type: bool  default: true

  --concurrent-allocation (concurrently allocate in old space)

        type: bool  default: false

  --local-heaps (allow heap access from background tasks)

        type: bool  default: false

  --parallel-marking (use parallel marking in atomic pause)

        type: bool  default: true

  --ephemeron-fixpoint-iterations (number of fixpoint iterations it takes to switch to linear ephemeron algorithm)

        type: int  default: 10

  --trace-concurrent-marking (trace concurrent marking)

        type: bool  default: false

  --concurrent-store-buffer (use concurrent store buffer processing)

        type: bool  default: true

  --concurrent-sweeping (use concurrent sweeping)

        type: bool  default: true

  --parallel-compaction (use parallel compaction)

        type: bool  default: true

  --parallel-pointer-update (use parallel pointer update during compaction)

        type: bool  default: true

  --detect-ineffective-gcs-near-heap-limit (trigger out-of-memory failure to avoid GC storm near heap limit)

        type: bool  default: true

  --trace-incremental-marking (trace progress of the incremental marking)

        type: bool  default: false

  --trace-stress-marking (trace stress marking progress)

        type: bool  default: false

  --trace-stress-scavenge (trace stress scavenge progress)

        type: bool  default: false

  --track-gc-object-stats (track object counts and memory usage)

        type: bool  default: false

  --trace-gc-object-stats (trace object counts and memory usage)

        type: bool  default: false

  --trace-zone-stats (trace zone memory usage)

        type: bool  default: false

  --track-retaining-path (enable support for tracking retaining path)

        type: bool  default: false

  --concurrent-array-buffer-freeing (free array buffer allocations on a background thread)

        type: bool  default: true

  --gc-stats (Used by tracing internally to enable gc statistics)

        type: int  default: 0

  --track-detached-contexts (track native contexts that are expected to be garbage collected)

        type: bool  default: true

  --trace-detached-contexts (trace native contexts that are expected to be garbage collected)

        type: bool  default: false

  --move-object-start (enable moving of object starts)

        type: bool  default: true

  --memory-reducer (use memory reducer)

        type: bool  default: true

  --memory-reducer-for-small-heaps (use memory reducer for small heaps)

        type: bool  default: true

  --heap-growing-percent (specifies heap growing factor as (1 + heap_growing_percent/100))

        type: int  default: 0

  --v8-os-page-size (override OS page size (in KBytes))

        type: int  default: 0

  --always-compact (Perform compaction on every full GC)

        type: bool  default: false

  --never-compact (Never perform compaction on full GC - testing only)

        type: bool  default: false

  --compact-code-space (Compact code space on full collections)

        type: bool  default: true

  --flush-bytecode (flush of bytecode when it has not been executed recently)

        type: bool  default: true

  --stress-flush-bytecode (stress bytecode flushing)

        type: bool  default: false

  --use-marking-progress-bar (Use a progress bar to scan large objects in increments when incremental marking is active.)

        type: bool  default: true

  --stress-per-context-marking-worklist (Use per-context worklist for marking)

        type: bool  default: false

  --force-marking-deque-overflows (force overflows of marking deque by reducing it's size to 64 words)

        type: bool  default: false

  --stress-compaction (stress the GC compactor to flush out bugs (implies --force_marking_deque_overflows))

        type: bool  default: false

  --stress-compaction-random (Stress GC compaction by selecting random percent of pages as evacuation candidates. It overrides stress_compaction.)

        type: bool  default: false

  --stress-incremental-marking (force incremental marking for small heaps and run it more often)

        type: bool  default: false

  --fuzzer-gc-analysis (prints number of allocations and enables analysis mode for gc fuzz testing, e.g. --stress-marking, --stress-scavenge)

        type: bool  default: false

  --stress-marking (force marking at random points between 0 and X (inclusive) percent of the regular marking start limit)

        type: int  default: 0

  --stress-scavenge (force scavenge at random points between 0 and X (inclusive) percent of the new space capacity)

        type: int  default: 0

  --gc-experiment-background-schedule (new background GC schedule heuristics)

        type: bool  default: false

  --gc-experiment-less-compaction (less compaction in non-memory reducing mode)

        type: bool  default: false

  --disable-abortjs (disables AbortJS runtime function)

        type: bool  default: false

  --randomize-all-allocations (randomize virtual memory reservations by ignoring any hints passed when allocating pages)

        type: bool  default: false

  --manual-evacuation-candidates-selection (Test mode only flag. It allows an unit test to select evacuation candidates pages (requires --stress_compaction).)

        type: bool  default: false

  --fast-promotion-new-space (fast promote new space on high survival rates)

        type: bool  default: false

  --clear-free-memory (initialize free memory with 0)

        type: bool  default: false

  --young-generation-large-objects (allocates large objects by default in the young generation large object space)

        type: bool  default: true

  --debug-code (generate extra code (assertions) for debugging)

        type: bool  default: false

  --code-comments (emit comments in code disassembly; for more readable source positions you should add --no-concurrent_recompilation)

        type: bool  default: false

  --enable-sse3 (enable use of SSE3 instructions if available)

        type: bool  default: true

  --enable-ssse3 (enable use of SSSE3 instructions if available)

        type: bool  default: true

  --enable-sse4-1 (enable use of SSE4.1 instructions if available)

        type: bool  default: true

  --enable-sse4-2 (enable use of SSE4.2 instructions if available)

        type: bool  default: true

  --enable-sahf (enable use of SAHF instruction if available (X64 only))

        type: bool  default: true

  --enable-avx (enable use of AVX instructions if available)

        type: bool  default: true

  --enable-fma3 (enable use of FMA3 instructions if available)

        type: bool  default: true

  --enable-bmi1 (enable use of BMI1 instructions if available)

        type: bool  default: true

  --enable-bmi2 (enable use of BMI2 instructions if available)

        type: bool  default: true

  --enable-lzcnt (enable use of LZCNT instruction if available)

        type: bool  default: true

  --enable-popcnt (enable use of POPCNT instruction if available)

        type: bool  default: true

  --arm-arch (generate instructions for the selected ARM architecture if available: armv6, armv7, armv7+sudiv or armv8)

        type: string  default: armv8

  --force-long-branches (force all emitted branches to be in long mode (MIPS/PPC only))

        type: bool  default: false

  --mcpu (enable optimization for specific cpu)

        type: string  default: auto

  --partial-constant-pool (enable use of partial constant pools (X64 only))

        type: bool  default: true

  --enable-source-at-csa-bind (Include source information in the binary at CSA bind locations.)

        type: bool  default: false

  --enable-armv7 (deprecated (use --arm_arch instead))

        type: maybe_bool  default: unset

  --enable-vfp3 (deprecated (use --arm_arch instead))

        type: maybe_bool  default: unset

  --enable-32dregs (deprecated (use --arm_arch instead))

        type: maybe_bool  default: unset

  --enable-neon (deprecated (use --arm_arch instead))

        type: maybe_bool  default: unset

  --enable-sudiv (deprecated (use --arm_arch instead))

        type: maybe_bool  default: unset

  --enable-armv8 (deprecated (use --arm_arch instead))

        type: maybe_bool  default: unset

  --enable-regexp-unaligned-accesses (enable unaligned accesses for the regexp engine)

        type: bool  default: true

  --script-streaming (enable parsing on background)

        type: bool  default: true

  --stress-background-compile (stress test parsing on background)

        type: bool  default: false

  --finalize-streaming-on-background (perform the script streaming finalization on the background thread)

        type: bool  default: false

  --disable-old-api-accessors (Disable old-style API accessors whose setters trigger through the prototype chain)

        type: bool  default: false

  --expose-gc (expose gc extension)

        type: bool  default: false

  --expose-gc-as (expose gc extension under the specified name)

        type: string  default: nullptr

  --expose-externalize-string (expose externalize string extension)

        type: bool  default: false

  --expose-trigger-failure (expose trigger-failure extension)

        type: bool  default: false

  --stack-trace-limit (number of stack frames to capture)

        type: int  default: 10

  --builtins-in-stack-traces (show built-in functions in stack traces)

        type: bool  default: false

  --experimental-stack-trace-frames (enable experimental frames (API/Builtins) and stack trace layout)

        type: bool  default: false

  --disallow-code-generation-from-strings (disallow eval and friends)

        type: bool  default: false

  --expose-async-hooks (expose async_hooks object)

        type: bool  default: false

  --expose-cputracemark-as (expose cputracemark extension under the specified name)

        type: string  default: nullptr

  --allow-unsafe-function-constructor (allow invoking the function constructor without security checks)

        type: bool  default: false

  --force-slow-path (always take the slow path for builtins)

        type: bool  default: false

  --test-small-max-function-context-stub-size (enable testing the function context size overflow path by making the maximum size smaller)

        type: bool  default: false

  --inline-new (use fast inline allocation)

        type: bool  default: true

  --trace (trace function calls)

        type: bool  default: false

  --lazy (use lazy compilation)

        type: bool  default: true

  --max-lazy (ignore eager compilation hints)

        type: bool  default: false

  --trace-opt (trace lazy optimization)

        type: bool  default: false

  --trace-opt-verbose (extra verbose compilation tracing)

        type: bool  default: false

  --trace-opt-stats (trace lazy optimization statistics)

        type: bool  default: false

  --trace-deopt (trace optimize function deoptimization)

        type: bool  default: false

  --trace-file-names (include file names in trace-opt/trace-deopt output)

        type: bool  default: false

  --always-opt (always try to optimize functions)

        type: bool  default: false

  --always-osr (always try to OSR functions)

        type: bool  default: false

  --prepare-always-opt (prepare for turning on always opt)

        type: bool  default: false

  --trace-serializer (print code serializer trace)

        type: bool  default: false

  --compilation-cache (enable compilation cache)

        type: bool  default: true

  --cache-prototype-transitions (cache prototype transitions)

        type: bool  default: true

  --parallel-compile-tasks (enable parallel compile tasks)

        type: bool  default: false

  --compiler-dispatcher (enable compiler dispatcher)

        type: bool  default: false

  --trace-compiler-dispatcher (trace compiler dispatcher activity)

        type: bool  default: false

  --cpu-profiler-sampling-interval (CPU profiler sampling interval in microseconds)

        type: int  default: 1000

  --trace-side-effect-free-debug-evaluate (print debug messages for side-effect-free debug-evaluate for testing)

        type: bool  default: false

  --hard-abort (abort by crashing)

        type: bool  default: true

  --expose-inspector-scripts (expose injected-script-source.js for debugging)

        type: bool  default: false

  --stack-size (default size of stack region v8 is allowed to use (in kBytes))

        type: int  default: 984

  --max-stack-trace-source-length (maximum length of function source code printed in a stack trace.)

        type: int  default: 300

  --clear-exceptions-on-js-entry (clear pending exceptions when entering JavaScript)

        type: bool  default: false

  --histogram-interval (time interval in ms for aggregating memory histograms)

        type: int  default: 600000

  --heap-profiler-trace-objects (Dump heap object allocations/movements/size_updates)

        type: bool  default: false

  --heap-profiler-use-embedder-graph (Use the new EmbedderGraph API to get embedder nodes)

        type: bool  default: true

  --heap-snapshot-string-limit (truncate strings to this length in the heap snapshot)

        type: int  default: 1024

  --sampling-heap-profiler-suppress-randomness (Use constant sample intervals to eliminate test flakiness)

        type: bool  default: false

  --use-idle-notification (Use idle notification to reduce memory footprint.)

        type: bool  default: true

  --trace-ic (trace inline cache state transitions for tools/ic-processor)

        type: bool  default: false

  --modify-field-representation-inplace (enable in-place field representation updates)

        type: bool  default: true

  --max-polymorphic-map-count (maximum number of maps to track in POLYMORPHIC state)

        type: int  default: 4

  --native-code-counters (generate extra code for manipulating stats counters)

        type: bool  default: false

  --thin-strings (Enable ThinString support)

        type: bool  default: true

  --trace-prototype-users (Trace updates to prototype user tracking)

        type: bool  default: false

  --use-verbose-printer (allows verbose printing)

        type: bool  default: true

  --trace-for-in-enumerate (Trace for-in enumerate slow-paths)

        type: bool  default: false

  --trace-maps (trace map creation)

        type: bool  default: false

  --trace-maps-details (also log map details)

        type: bool  default: true

  --allow-natives-syntax (allow natives syntax)

        type: bool  default: false

  --allow-natives-for-fuzzing (allow only natives explicitly whitelisted for fuzzers)

        type: bool  default: false

  --allow-natives-for-differential-fuzzing (allow only natives explicitly whitelisted for differential fuzzers)

        type: bool  default: false

  --parse-only (only parse the sources)

        type: bool  default: false

  --trace-sim (Trace simulator execution)

        type: bool  default: false

  --debug-sim (Enable debugging the simulator)

        type: bool  default: false

  --check-icache (Check icache flushes in ARM and MIPS simulator)

        type: bool  default: false

  --stop-sim-at (Simulator stop after x number of instructions)

        type: int  default: 0

  --sim-stack-alignment (Stack alingment in bytes in simulator (4 or 8, 8 is default))

        type: int  default: 8

  --sim-stack-size (Stack size of the ARM64, MIPS64 and PPC64 simulator in kBytes (default is 2 MB))

        type: int  default: 2048

  --log-colour (When logging, try to use coloured output.)

        type: bool  default: false

  --trace-sim-messages (Trace simulator debug messages. Implied by --trace-sim.)

        type: bool  default: false

  --async-stack-traces (include async stack traces in Error.stack)

        type: bool  default: true

  --stack-trace-on-illegal (print stack trace when an illegal exception is thrown)

        type: bool  default: false

  --abort-on-uncaught-exception (abort program (dump core) when an uncaught exception is thrown)

        type: bool  default: false

  --correctness-fuzzer-suppressions (Suppress certain unspecified behaviors to ease correctness fuzzing: Abort program when the stack overflows or a string exceeds maximum length (as opposed to throwing RangeError). Use a fixed suppression string for error messages.)

        type: bool  default: false

  --randomize-hashes (randomize hashes to avoid predictable hash collisions (with snapshots this option cannot override the baked-in seed))

        type: bool  default: true

  --rehash-snapshot (rehash strings from the snapshot to override the baked-in seed)

        type: bool  default: true

  --hash-seed (Fixed seed to use to hash property keys (0 means random)(with snapshots this option cannot override the baked-in seed))

        type: uint64  default: 0

  --random-seed (Default seed for initializing random generator (0, the default, means to use system random).)

        type: int  default: 0

  --fuzzer-random-seed (Default seed for initializing fuzzer random generator (0, the default, means to use v8's random number generator seed).)

        type: int  default: 0

  --trace-rail (trace RAIL mode)

        type: bool  default: false

  --print-all-exceptions (print exception object and stack trace on each thrown exception)

        type: bool  default: false

  --detailed-error-stack-trace (includes arguments for each function call in the error stack frames array)

        type: bool  default: false

  --adjust-os-scheduling-parameters (adjust OS specific scheduling params for the isolate)

        type: bool  default: true

  --runtime-call-stats (report runtime call counts and times)

        type: bool  default: false

  --rcs (report runtime call counts and times)

        type: bool  default: false

  --rcs-cpu-time (report runtime times in cpu time (the default is wall time))

        type: bool  default: false

  --profile-deserialization (Print the time it takes to deserialize the snapshot.)

        type: bool  default: false

  --serialization-statistics (Collect statistics on serialized objects.)

        type: bool  default: false

  --serialization-chunk-size (Custom size for serialization chunks)

        type: uint  default: 4096

  --regexp-optimization (generate optimized regexp code)

        type: bool  default: true

  --regexp-mode-modifiers (enable inline flags in regexp.)

        type: bool  default: false

  --regexp-interpret-all (interpret all regexp code)

        type: bool  default: false

  --regexp-tier-up (enable regexp interpreter and tier up to the compiler after the number of executions set by the tier up ticks flag)

        type: bool  default: true

  --regexp-tier-up-ticks (set the number of executions for the regexp interpreter before tiering-up to the compiler)

        type: int  default: 1

  --regexp-peephole-optimization (enable peephole optimization for regexp bytecode)

        type: bool  default: true

  --trace-regexp-peephole-optimization (trace regexp bytecode peephole optimization)

        type: bool  default: false

  --trace-regexp-bytecodes (trace regexp bytecode execution)

        type: bool  default: false

  --trace-regexp-assembler (trace regexp macro assembler calls.)

        type: bool  default: false

  --trace-regexp-parser (trace regexp parsing)

        type: bool  default: false

  --trace-regexp-tier-up (trace regexp tiering up execution)

        type: bool  default: false

  --testing-bool-flag (testing_bool_flag)

        type: bool  default: true

  --testing-maybe-bool-flag (testing_maybe_bool_flag)

        type: maybe_bool  default: unset

  --testing-int-flag (testing_int_flag)

        type: int  default: 13

  --testing-float-flag (float-flag)

        type: float  default: 2.5

  --testing-string-flag (string-flag)

        type: string  default: Hello, world!

  --testing-prng-seed (Seed used for threading test randomness)

        type: int  default: 42

  --testing-d8-test-runner (test runner turns on this flag to enable a check that the function was prepared for optimization before marking it for optimization)

        type: bool  default: false

  --fuzzing (Fuzzers use this flag to signal that they are ... fuzzing. This causes intrinsics to fail silently (e.g. return undefined) on invalid usage.)

        type: bool  default: false

  --embedded-src (Path for the generated embedded data file. (mksnapshot only))

        type: string  default: nullptr

  --embedded-variant (Label to disambiguate symbols in embedded data file. (mksnapshot only))

        type: string  default: nullptr

  --startup-src (Write V8 startup as C++ src. (mksnapshot only))

        type: string  default: nullptr

  --startup-blob (Write V8 startup blob file. (mksnapshot only))

        type: string  default: nullptr

  --target-arch (The mksnapshot target arch. (mksnapshot only))

        type: string  default: nullptr

  --target-os (The mksnapshot target os. (mksnapshot only))

        type: string  default: nullptr

  --target-is-simulator (Instruct mksnapshot that the target is meant to run in the simulator and it can generate simulator-specific instructions. (mksnapshot only))

        type: bool  default: false

  --minor-mc-parallel-marking (use parallel marking for the young generation)

        type: bool  default: true

  --trace-minor-mc-parallel-marking (trace parallel marking for the young generation)

        type: bool  default: false

  --minor-mc (perform young generation mark compact GCs)

        type: bool  default: false

  --help (Print usage message, including flags, on console)

        type: bool  default: true

  --dump-counters (Dump counters on exit)

        type: bool  default: false

  --dump-counters-nvp (Dump counters as name-value pairs on exit)

        type: bool  default: false

  --use-external-strings (Use external strings for source code)

        type: bool  default: false

  --map-counters (Map counters to a file)

        type: string  default: 

  --mock-arraybuffer-allocator (Use a mock ArrayBuffer allocator for testing.)

        type: bool  default: false

  --mock-arraybuffer-allocator-limit (Memory limit for mock ArrayBuffer allocator used to simulate OOM for testing.)

        type: size_t  default: 0

  --log (Minimal logging (no API, code, GC, suspect, or handles samples).)

        type: bool  default: false

  --log-all (Log all events to the log file.)

        type: bool  default: false

  --log-api (Log API events to the log file.)

        type: bool  default: false

  --log-code (Log code events to the log file without profiling.)

        type: bool  default: false

  --log-handles (Log global handle events.)

        type: bool  default: false

  --log-suspect (Log suspect operations.)

        type: bool  default: false

  --log-source-code (Log source code.)

        type: bool  default: false

  --log-function-events (Log function events (parse, compile, execute) separately.)

        type: bool  default: false

  --prof (Log statistical profiling information (implies --log-code).)

        type: bool  default: false

  --detailed-line-info (Always generate detailed line information for CPU profiling.)

        type: bool  default: false

  --prof-sampling-interval (Interval for --prof samples (in microseconds).)

        type: int  default: 1000

  --prof-cpp (Like --prof, but ignore generated code.)

        type: bool  default: false

  --prof-browser-mode (Used with --prof, turns on browser-compatible mode for profiling.)

        type: bool  default: true

  --logfile (Specify the name of the log file.)

        type: string  default: v8.log

  --logfile-per-isolate (Separate log files for each isolate.)

        type: bool  default: true

  --ll-prof (Enable low-level linux profiler.)

        type: bool  default: false

  --gc-fake-mmap (Specify the name of the file for fake gc mmap used in ll_prof)

        type: string  default: /tmp/__v8_gc__

  --log-internal-timer-events (Time internal events.)

        type: bool  default: false

  --redirect-code-traces (output deopt information and disassembly into file code-<pid>-<isolate id>.asm)

        type: bool  default: false

  --redirect-code-traces-to (output deopt information and disassembly into the given file)

        type: string  default: nullptr

  --print-opt-source (print source code of optimized and inlined functions)

        type: bool  default: false

  --vtune-prof-annotate-wasm (Used when v8_enable_vtunejit is enabled, load wasm source map and provide annotate support (experimental).)

        type: bool  default: false

  --win64-unwinding-info (Enable unwinding info for Windows/x64)

        type: bool  default: true

  --interpreted-frames-native-stack (Show interpreted frames on the native stack (useful for external profilers).)

        type: bool  default: false

  --trace-elements-transitions (trace elements transitions)

        type: bool  default: false

  --trace-creation-allocation-sites (trace the creation of allocation sites)

        type: bool  default: false

  --print-code (print generated code)

        type: bool  default: false

  --print-opt-code (print optimized code)

        type: bool  default: false

  --print-opt-code-filter (filter for printing optimized code)

        type: string  default: *

  --print-code-verbose (print more information for code)

        type: bool  default: false

  --print-builtin-code (print generated code for builtins)

        type: bool  default: false

  --print-builtin-code-filter (filter for printing builtin code)

        type: string  default: *

  --print-regexp-code (print generated regexp code)

        type: bool  default: false

  --print-regexp-bytecode (print generated regexp bytecode)

        type: bool  default: false

  --print-builtin-size (print code size for builtins)

        type: bool  default: false

  --sodium (print generated code output suitable for use with the Sodium code viewer)

        type: bool  default: false

  --print-all-code (enable all flags related to printing code)

        type: bool  default: false

  --predictable (enable predictable mode)

        type: bool  default: false

  --predictable-gc-schedule (Predictable garbage collection schedule. Fixes heap growing, idle, and memory reducing behavior.)

        type: bool  default: false

  --single-threaded (disable the use of background tasks)

        type: bool  default: false

  --single-threaded-gc (disable the use of background gc tasks)

        type: bool  default: false