Table of Contents generated with DocToc
- use_strict
false
{Boolean} - es_staging
false
{Boolean} - harmony_typeof
false
{Boolean} - harmony_scoping
false
{Boolean} - harmony_modules
false
{Boolean} - harmony_symbols
false
{Boolean} - harmony_proxies
false
{Boolean} - harmony_collections
false
{Boolean} - harmony_generators
false
{Boolean} - harmony_iteration
false
{Boolean} - harmony_numeric_literals
false
{Boolean} - harmony_strings
false
{Boolean} - harmony_arrays
false
{Boolean} - harmony_maths
false
{Boolean} - harmony
false
{Boolean} - packed_arrays
true
{Boolean} - smi_only_arrays
true
{Boolean} - compiled_keyed_dictionary_loads
true
{Boolean} - clever_optimizations
true
{Boolean} - pretenuring
true
{Boolean} - pretenuring_call_new
false
{Boolean} - allocation_site_pretenuring
true
{Boolean} - trace_pretenuring
false
{Boolean} - trace_pretenuring_statistics
false
{Boolean} - track_fields
true
{Boolean} - track_double_fields
true
{Boolean} - track_heap_object_fields
true
{Boolean} - track_computed_fields
true
{Boolean} - smi_binop
true
{Boolean} - optimize_for_size
false
{Boolean} - unbox_double_arrays
true
{Boolean} - string_slices
true
{Boolean} - crankshaft
true
{Boolean} - hydrogen_filter
*
{String} - use_gvn
true
{Boolean} - gvn_iterations
3
{Integer} - use_canonicalizing
true
{Boolean} - use_inlining
true
{Boolean} - use_escape_analysis
true
{Boolean} - use_allocation_folding
true
{Boolean} - use_local_allocation_folding
false
{Boolean} - use_write_barrier_elimination
true
{Boolean} - max_inlining_levels
5
{Integer} - max_inlined_source_size
600
{Integer} - max_inlined_nodes
196
{Integer} - max_inlined_nodes_cumulative
400
{Integer} - loop_invariant_code_motion
true
{Boolean} - fast_math
true
{Boolean} - collect_megamorphic_maps_from_stub_cache
true
{Boolean} - hydrogen_stats
false
{Boolean} - trace_check_elimination
false
{Boolean} - trace_hydrogen
false
{Boolean} - trace_hydrogen_filter
*
{String} - trace_hydrogen_stubs
false
{Boolean} - trace_hydrogen_file
undefined
{String} - trace_phase
HLZ
{String} - trace_inlining
false
{Boolean} - trace_load_elimination
false
{Boolean} - trace_store_elimination
false
{Boolean} - trace_alloc
false
{Boolean} - trace_all_uses
false
{Boolean} - trace_range
false
{Boolean} - trace_gvn
false
{Boolean} - trace_representation
false
{Boolean} - trace_escape_analysis
false
{Boolean} - trace_allocation_folding
false
{Boolean} - trace_track_allocation_sites
false
{Boolean} - trace_migration
false
{Boolean} - trace_generalization
false
{Boolean} - stress_pointer_maps
false
{Boolean} - stress_environments
false
{Boolean} - deopt_every_n_times
0
{Integer} - deopt_every_n_garbage_collections
0
{Integer} - print_deopt_stress
false
{Boolean} - trap_on_deopt
false
{Boolean} - trap_on_stub_deopt
false
{Boolean} - deoptimize_uncommon_cases
true
{Boolean} - polymorphic_inlining
true
{Boolean} - use_osr
true
{Boolean} - array_bounds_checks_elimination
true
{Boolean} - trace_bce
false
{Boolean} - array_bounds_checks_hoisting
false
{Boolean} - array_index_dehoisting
true
{Boolean} - analyze_environment_liveness
true
{Boolean} - load_elimination
true
{Boolean} - check_elimination
true
{Boolean} - store_elimination
false
{Boolean} - dead_code_elimination
true
{Boolean} - fold_constants
true
{Boolean} - trace_dead_code_elimination
false
{Boolean} - unreachable_code_elimination
true
{Boolean} - trace_osr
false
{Boolean} - stress_runs
0
{Integer} - optimize_closures
true
{Boolean} - lookup_sample_by_shared
true
{Boolean} - cache_optimized_code
true
{Boolean} - flush_optimized_code_cache
true
{Boolean} - inline_construct
true
{Boolean} - inline_arguments
true
{Boolean} - inline_accessors
true
{Boolean} - escape_analysis_iterations
2
{Integer} - optimize_for_in
true
{Boolean} - opt_safe_uint32_operations
true
{Boolean} - concurrent_recompilation
true
{Boolean} - trace_concurrent_recompilation
false
{Boolean} - concurrent_recompilation_queue_length
8
{Integer} - concurrent_recompilation_delay
0
{Integer} - block_concurrent_recompilation
false
{Boolean} - concurrent_osr
false
{Boolean} - omit_map_checks_for_leaf_maps
true
{Boolean} - typed_array_max_size_in_heap
64
{Integer} - frame_count
1
{Integer} - interrupt_budget
6144
{Integer} - type_info_threshold
25
{Integer} - self_opt_count
130
{Integer} - trace_opt_verbose
false
{Boolean} - debug_code
false
{Boolean} - code_comments
false
{Boolean} - enable_sse2
true
{Boolean} - enable_sse3
true
{Boolean} - enable_sse4_1
true
{Boolean} - enable_cmov
true
{Boolean} - enable_sahf
true
{Boolean} - enable_vfp3
true
{Boolean} - enable_armv7
true
{Boolean} - enable_neon
true
{Boolean} - enable_sudiv
true
{Boolean} - enable_movw_movt
false
{Boolean} - enable_unaligned_accesses
true
{Boolean} - enable_32dregs
true
{Boolean} - enable_vldr_imm
false
{Boolean} - force_long_branches
false
{Boolean} - expose_natives_as
undefined
{String} - expose_debug_as
undefined
{String} - expose_free_buffer
false
{Boolean} - expose_gc
false
{Boolean} - expose_gc_as
undefined
{String} - expose_externalize_string
false
{Boolean} - expose_trigger_failure
false
{Boolean} - stack_trace_limit
10
{Integer} - builtins_in_stack_traces
false
{Boolean} - disable_native_files
false
{Boolean} - inline_new
true
{Boolean} - trace_codegen
false
{Boolean} - trace
false
{Boolean} - mask_constants_with_cookie
true
{Boolean} - lazy
true
{Boolean} - trace_opt
false
{Boolean} - trace_opt_stats
false
{Boolean} - opt
true
{Boolean} - always_opt
false
{Boolean} - always_osr
false
{Boolean} - prepare_always_opt
false
{Boolean} - trace_deopt
false
{Boolean} - trace_stub_failures
false
{Boolean} - min_preparse_length
1024
{Integer} - always_full_compiler
false
{Boolean} - max_opt_count
10
{Integer} - compilation_cache
true
{Boolean} - cache_prototype_transitions
true
{Boolean} - cpu_profiler_sampling_interval
1000
{Integer} - trace_debug_json
false
{Boolean} - trace_js_array_abuse
false
{Boolean} - trace_external_array_abuse
false
{Boolean} - trace_array_abuse
false
{Boolean} - debugger_auto_break
true
{Boolean} - enable_liveedit
true
{Boolean} - hard_abort
true
{Boolean} - stack_size
984
{Integer} - max_stack_trace_source_length
300
{Integer} - always_inline_smi_code
false
{Boolean} - max_new_space_size
0
{Integer} - max_old_space_size
0
{Integer} - max_executable_size
0
{Integer} - gc_global
false
{Boolean} - gc_interval
-1
{Integer} - trace_gc
false
{Boolean} - trace_gc_nvp
false
{Boolean} - trace_gc_ignore_scavenger
false
{Boolean} - print_cumulative_gc_stat
false
{Boolean} - print_max_heap_committed
false
{Boolean} - trace_gc_verbose
false
{Boolean} - trace_fragmentation
false
{Boolean} - trace_external_memory
false
{Boolean} - collect_maps
true
{Boolean} - weak_embedded_maps_in_optimized_code
true
{Boolean} - weak_embedded_objects_in_optimized_code
true
{Boolean} - flush_code
true
{Boolean} - flush_code_incrementally
true
{Boolean} - trace_code_flushing
false
{Boolean} - age_code
true
{Boolean} - incremental_marking
true
{Boolean} - incremental_marking_steps
true
{Boolean} - trace_incremental_marking
false
{Boolean} - track_gc_object_stats
false
{Boolean} - parallel_sweeping
true
{Boolean} - concurrent_sweeping
false
{Boolean} - sweeper_threads
0
{Integer} - job_based_sweeping
false
{Boolean} - heap_profiler_trace_objects
false
{Boolean} - use_idle_notification
true
{Boolean} - use_ic
true
{Boolean} - native_code_counters
false
{Boolean} - always_compact
false
{Boolean} - lazy_sweeping
true
{Boolean} - never_compact
false
{Boolean} - compact_code_space
true
{Boolean} - incremental_code_compaction
true
{Boolean} - cleanup_code_caches_at_gc
true
{Boolean} - use_marking_progress_bar
true
{Boolean} - zap_code_space
true
{Boolean} - random_seed
0
{Integer} - use_verbose_printer
true
{Boolean} - allow_natives_syntax
false
{Boolean} - trace_parse
false
{Boolean} - trace_sim
false
{Boolean} - debug_sim
false
{Boolean} - check_icache
false
{Boolean} - stop_sim_at
0
{Integer} - sim_stack_alignment
8
{Integer} - sim_stack_size
2048
{Integer} - log_regs_modified
true
{Boolean} - log_colour
true
{Boolean} - ignore_asm_unimplemented_break
false
{Boolean} - trace_sim_messages
false
{Boolean} - stack_trace_on_illegal
false
{Boolean} - abort_on_uncaught_exception
false
{Boolean} - randomize_hashes
true
{Boolean} - hash_seed
0
{Integer} - profile_deserialization
false
{Boolean} - regexp_optimization
true
{Boolean} - testing_string_flag
Hello, world!
{String} - testing_serialization_file
/tmp/serdes
{String} - extra_code
undefined
{String} - profile_hydrogen_code_stub_compilation
false
{Boolean} - predictable
false
{Boolean} - help
false
{Boolean} - dump_counters
false
{Boolean} - map_counters `` {String}
- debug_compile_events
true
{Boolean} - debug_script_collected_events
true
{Boolean} - gdbjit
false
{Boolean} - gdbjit_full
false
{Boolean} - gdbjit_dump
false
{Boolean} - gdbjit_dump_filter `` {String}
- force_marking_deque_overflows
false
{Boolean} - stress_compaction
false
{Boolean} - print_source
false
{Boolean} - print_builtin_source
false
{Boolean} - print_ast
false
{Boolean} - print_builtin_ast
false
{Boolean} - stop_at `` {String}
- trap_on_abort
false
{Boolean} - print_builtin_scopes
false
{Boolean} - print_scopes
false
{Boolean} - trace_contexts
false
{Boolean} - gc_greedy
false
{Boolean} - gc_verbose
false
{Boolean} - heap_stats
false
{Boolean} - code_stats
false
{Boolean} - verify_native_context_separation
false
{Boolean} - print_handles
false
{Boolean} - print_global_handles
false
{Boolean} - trace_ic
false
{Boolean} - print_interfaces
false
{Boolean} - print_interface_details
false
{Boolean} - print_interface_depth
5
{Integer} - trace_normalization
false
{Boolean} - trace_lazy
false
{Boolean} - collect_heap_spill_statistics
false
{Boolean} - trace_isolates
false
{Boolean} - regexp_possessive_quantifier
false
{Boolean} - trace_regexp_bytecodes
false
{Boolean} - trace_regexp_assembler
false
{Boolean} - log
false
{Boolean} - log_all
false
{Boolean} - log_runtime
false
{Boolean} - log_api
false
{Boolean} - log_code
false
{Boolean} - log_gc
false
{Boolean} - log_handles
false
{Boolean} - log_snapshot_positions
false
{Boolean} - log_suspect
false
{Boolean} - prof
false
{Boolean} - prof_browser_mode
true
{Boolean} - log_regexp
false
{Boolean} - logfile
v8.log
{String} - logfile_per_isolate
true
{Boolean} - ll_prof
false
{Boolean} - perf_basic_prof
false
{Boolean} - perf_jit_prof
false
{Boolean} - gc_fake_mmap
/tmp/__v8_gc__
{String} - log_internal_timer_events
false
{Boolean} - log_timer_events
false
{Boolean} - log_instruction_stats
false
{Boolean} - log_instruction_file
arm64_inst.csv
{String} - log_instruction_period
4194304
{Integer} - redirect_code_traces
false
{Boolean} - redirect_code_traces_to
undefined
{String} - hydrogen_track_positions
false
{Boolean} - trace_elements_transitions
false
{Boolean} - trace_creation_allocation_sites
false
{Boolean} - print_code_stubs
false
{Boolean} - test_secondary_stub_cache
false
{Boolean} - test_primary_stub_cache
false
{Boolean} - print_code
false
{Boolean} - print_opt_code
false
{Boolean} - print_unopt_code
false
{Boolean} - print_code_verbose
false
{Boolean} - print_builtin_code
false
{Boolean} - enable_ool_constant_pool
false
{Boolean}
false
{Boolean}
use_strict enforce strict mode
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
es_staging enable upcoming ES6+ features
- default:
false
- type:
Boolean
- readonly:
false
Implications
- harmony_maths
false
{Boolean}
harmony_typeof enable harmony semantics for typeof
- default:
false
- type:
Boolean
- readonly:
false
Note: this feature seems to work in v8 even without turning on this flag.
Resources
- rejected? proposal
false
{Boolean}
harmony_scoping enable harmony block scoping
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
harmony_modules enable harmony modules (implies block scoping)
- default:
false
- type:
Boolean
- readonly:
false
Implications
- harmony_scoping
References
false
{Boolean}
harmony_symbols enable harmony symbols (a.k.a. private names)
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
harmony_proxies enable harmony proxies
NOTE: This flag cannot be configured after the process started up!
- default:
false
- type:
Boolean
- readonly:
false
Resources
false
{Boolean}
harmony_collections enable harmony collections (sets, maps)
NOTE: This flag cannot be configured after the process started up!
- default:
false
- type:
Boolean
- readonly:
false
References
false
{Boolean}
harmony_generators enable harmony generators
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
harmony_iteration enable harmony iteration (for-of)
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
harmony_numeric_literals enable harmony numeric literals (0o77, 0b11)
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
harmony_strings enable harmony string
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
harmony_arrays enable harmony arrays
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
harmony_maths enable harmony math functions
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
harmony enable all harmony features (except typeof)
- default:
false
- type:
Boolean
- readonly:
false
Implications
- harmony_scoping
- harmony_modules
- harmony_symbols
- harmony_proxies
- harmony_collections
- harmony_generators
- harmony_iteration
- harmony_numeric_literals
- harmony_strings
- harmony_arrays
- es_staging
true
{Boolean}
packed_arrays optimizes arrays that have no holes
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
smi_only_arrays tracks arrays with only smi values
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
compiled_keyed_dictionary_loads use optimizing compiler to generate keyed dictionary load stubs
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
clever_optimizations Optimize object size, Array shift, DOM strings and string +
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
pretenuring allocate objects in old space
- default:
true
- type:
Boolean
- readonly:
false
false
{Boolean}
pretenuring_call_new pretenure call new
- default:
false
- type:
Boolean
- readonly:
false
true
{Boolean}
allocation_site_pretenuring pretenure with allocation sites
- default:
true
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_pretenuring trace pretenuring decisions of HAllocate instructions
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_pretenuring_statistics trace allocation site pretenuring statistics
- default:
false
- type:
Boolean
- readonly:
false
true
{Boolean}
track_fields track fields with only smi values
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
track_double_fields track fields with double values
- default:
true
- type:
Boolean
- readonly:
false
Implications
- track_fields
true
{Boolean}
track_heap_object_fields track fields with heap values
- default:
true
- type:
Boolean
- readonly:
false
Implications
- track_fields
true
{Boolean}
track_computed_fields track computed boilerplate fields
- default:
true
- type:
Boolean
- readonly:
false
Implications
- track_fields
true
{Boolean}
smi_binop support smi representation in binary operations
- default:
true
- type:
Boolean
- readonly:
false
false
{Boolean}
optimize_for_size Enables optimizations which favor memory size over execution speed.
- default:
false
- type:
Boolean
- readonly:
false
true
{Boolean}
unbox_double_arrays automatically unbox arrays of doubles
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
string_slices use string slices
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
crankshaft use crankshaft
- default:
true
- type:
Boolean
- readonly:
false
Resources
*
{String}
hydrogen_filter optimization filter
- default:
*
- type:
String
- readonly:
false
true
{Boolean}
use_gvn use hydrogen global value numbering
- default:
true
- type:
Boolean
- readonly:
false
3
{Integer}
gvn_iterations maximum number of GVN fix-point iterations
- default:
3
- type:
Integer
- readonly:
false
true
{Boolean}
use_canonicalizing use hydrogen instruction canonicalizing
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
use_inlining use function inlining
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
use_escape_analysis use hydrogen escape analysis
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
use_allocation_folding use allocation folding
- default:
true
- type:
Boolean
- readonly:
false
false
{Boolean}
use_local_allocation_folding only fold in basic blocks
- default:
false
- type:
Boolean
- readonly:
false
true
{Boolean}
use_write_barrier_elimination eliminate write barriers targeting allocations in optimized code
- default:
true
- type:
Boolean
- readonly:
false
5
{Integer}
max_inlining_levels maximum number of inlining levels
- default:
5
- type:
Integer
- readonly:
false
600
{Integer}
max_inlined_source_size maximum source size in bytes considered for a single inlining
- default:
600
- type:
Integer
- readonly:
false
196
{Integer}
max_inlined_nodes maximum number of AST nodes considered for a single inlining
- default:
196
- type:
Integer
- readonly:
false
400
{Integer}
max_inlined_nodes_cumulative maximum cumulative number of AST nodes considered for inlining
- default:
400
- type:
Integer
- readonly:
false
true
{Boolean}
loop_invariant_code_motion loop invariant code motion
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
fast_math faster (but maybe less accurate) math functions
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
collect_megamorphic_maps_from_stub_cache crankshaft harvests type feedback from stub cache
- default:
true
- type:
Boolean
- readonly:
false
false
{Boolean}
hydrogen_stats print statistics for hydrogen
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_check_elimination trace check elimination phase
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_hydrogen trace generated hydrogen to file
- default:
false
- type:
Boolean
- readonly:
false
*
{String}
trace_hydrogen_filter hydrogen tracing filter
- default:
*
- type:
String
- readonly:
false
false
{Boolean}
trace_hydrogen_stubs trace generated hydrogen for stubs
- default:
false
- type:
Boolean
- readonly:
false
undefined
{String}
trace_hydrogen_file trace hydrogen to given file name
- default:
undefined
- type:
String
- readonly:
false
HLZ
{String}
trace_phase trace generated IR for specified phases
- default:
HLZ
- type:
String
- readonly:
false
false
{Boolean}
trace_inlining trace inlining decisions
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_load_elimination trace load elimination
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_store_elimination trace store elimination
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_alloc trace register allocator
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_all_uses trace all use positions
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_range trace range analysis
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_gvn trace global value numbering
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_representation trace representation types
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_escape_analysis trace hydrogen escape analysis
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_allocation_folding trace allocation folding
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_track_allocation_sites trace the tracking of allocation sites
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_migration trace object migration
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_generalization trace map generalization
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
stress_pointer_maps pointer map for every instruction
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
stress_environments environment for every instruction
- default:
false
- type:
Boolean
- readonly:
false
0
{Integer}
deopt_every_n_times deoptimize every n times a deopt point is passed
- default:
0
- type:
Integer
- readonly:
false
0
{Integer}
deopt_every_n_garbage_collections deoptimize every n garbage collections
- default:
0
- type:
Integer
- readonly:
false
false
{Boolean}
print_deopt_stress print number of possible deopt points
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trap_on_deopt put a break point before deoptimizing
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trap_on_stub_deopt put a break point before deoptimizing a stub
- default:
false
- type:
Boolean
- readonly:
false
true
{Boolean}
deoptimize_uncommon_cases deoptimize uncommon cases
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
polymorphic_inlining polymorphic inlining
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
use_osr use on-stack replacement
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
array_bounds_checks_elimination perform array bounds checks elimination
- default:
true
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_bce trace array bounds check elimination
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
array_bounds_checks_hoisting perform array bounds checks hoisting
- default:
false
- type:
Boolean
- readonly:
false
true
{Boolean}
array_index_dehoisting perform array index dehoisting
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
analyze_environment_liveness analyze liveness of environment slots and zap dead values
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
load_elimination use load elimination
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
check_elimination use check elimination
- default:
true
- type:
Boolean
- readonly:
false
Resources
false
{Boolean}
store_elimination use store elimination
- default:
false
- type:
Boolean
- readonly:
false
true
{Boolean}
dead_code_elimination use dead code elimination
- default:
true
- type:
Boolean
- readonly:
false
Resources
v8 hydrogen.cc v8 hydrogin-dce.cc
Note: not available below node: 0.10
- v8: 3.14
true
{Boolean}
fold_constants use constant folding
- default:
true
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_dead_code_elimination trace dead code elimination
- default:
false
- type:
Boolean
- readonly:
false
true
{Boolean}
unreachable_code_elimination eliminate unreachable code
- default:
true
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_osr trace on-stack replacement
- default:
false
- type:
Boolean
- readonly:
false
0
{Integer}
stress_runs number of stress runs
- default:
0
- type:
Integer
- readonly:
false
true
{Boolean}
optimize_closures optimize closures
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
lookup_sample_by_shared when picking a function to optimize, watch for shared function info, not JSFunction itself
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
cache_optimized_code cache optimized code for closures
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
flush_optimized_code_cache flushes the cache of optimized code for closures on every GC
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
inline_construct inline constructor calls
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
inline_arguments inline functions with arguments object
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
inline_accessors inline JavaScript accessors
- default:
true
- type:
Boolean
- readonly:
false
2
{Integer}
escape_analysis_iterations maximum number of escape analysis fix-point iterations
- default:
2
- type:
Integer
- readonly:
false
true
{Boolean}
optimize_for_in optimize functions containing for-in loops
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
opt_safe_uint32_operations allow uint32 values on optimize frames if they are used only in safe operations
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
concurrent_recompilation optimizing hot functions asynchronously on a separate thread
- default:
true
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_concurrent_recompilation track concurrent recompilation
- default:
false
- type:
Boolean
- readonly:
false
8
{Integer}
concurrent_recompilation_queue_length the length of the concurrent compilation queue
- default:
8
- type:
Integer
- readonly:
false
0
{Integer}
concurrent_recompilation_delay artificial compilation delay in ms
- default:
0
- type:
Integer
- readonly:
false
false
{Boolean}
block_concurrent_recompilation block queued jobs until released
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
concurrent_osr concurrent on-stack replacement
- default:
false
- type:
Boolean
- readonly:
false
Implications
- concurrent_recompilation
true
{Boolean}
omit_map_checks_for_leaf_maps do not emit check maps for constant values that have a leaf map, deoptimize the optimized code if the layout of the maps changes.
- default:
true
- type:
Boolean
- readonly:
false
64
{Integer}
typed_array_max_size_in_heap threshold for in-heap typed array
- default:
64
- type:
Integer
- readonly:
false
1
{Integer}
frame_count number of stack frames inspected by the profiler
- default:
1
- type:
Integer
- readonly:
false
6144
{Integer}
interrupt_budget execution budget before interrupt is triggered
- default:
6144
- type:
Integer
- readonly:
false
25
{Integer}
type_info_threshold percentage of ICs that must have type info to allow optimization
- default:
25
- type:
Integer
- readonly:
false
130
{Integer}
self_opt_count call count before self-optimization
- default:
130
- type:
Integer
- readonly:
false
false
{Boolean}
trace_opt_verbose extra verbose compilation tracing
- default:
false
- type:
Boolean
- readonly:
false
Implications
- trace_opt
false
{Boolean}
debug_code generate extra code (assertions) for debugging
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
code_comments emit comments in code disassembly
- default:
false
- type:
Boolean
- readonly:
false
Resources
Note: not available below node: 0.11
- v8: 3.25
true
{Boolean}
enable_sse2 enable use of SSE2 instructions if available
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
enable_sse3 enable use of SSE3 instructions if available
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
enable_sse4_1 enable use of SSE4.1 instructions if available
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
enable_cmov enable use of CMOV instruction if available
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
enable_sahf enable use of SAHF instruction if available (X64 only)
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
enable_vfp3 enable use of VFP3 instructions if available
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
enable_armv7 enable use of ARMv7 instructions if available (ARM only)
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
enable_neon enable use of NEON instructions if available (ARM only)
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
enable_sudiv enable use of SDIV and UDIV instructions if available (ARM only)
- default:
true
- type:
Boolean
- readonly:
false
false
{Boolean}
enable_movw_movt enable loading 32-bit constant by means of movw/movt instruction pairs (ARM only)
- default:
false
- type:
Boolean
- readonly:
false
true
{Boolean}
enable_unaligned_accesses enable unaligned accesses for ARMv7 (ARM only)
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
enable_32dregs enable use of d16-d31 registers on ARM - this requires VFP3
- default:
true
- type:
Boolean
- readonly:
false
false
{Boolean}
enable_vldr_imm enable use of constant pools for double immediate (ARM only)
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
force_long_branches force all emitted branches to be in long mode (MIPS only)
- default:
false
- type:
Boolean
- readonly:
false
undefined
{String}
expose_natives_as expose natives in global object
NOTE: This flag cannot be configured after the process started up!
- default:
undefined
- type:
String
- readonly:
false
undefined
{String}
expose_debug_as expose debug in global object
NOTE: This flag cannot be configured after the process started up!
- default:
undefined
- type:
String
- readonly:
false
false
{Boolean}
expose_free_buffer expose freeBuffer extension
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
expose_gc expose gc extension
NOTE: This flag cannot be configured after the process started up!
- default:
false
- type:
Boolean
- readonly:
false
undefined
{String}
expose_gc_as expose gc extension under the specified name
NOTE: This flag cannot be configured after the process started up!
- default:
undefined
- type:
String
- readonly:
false
Implications
- expose_gc
false
{Boolean}
expose_externalize_string expose externalize string extension
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
expose_trigger_failure expose trigger-failure extension
- default:
false
- type:
Boolean
- readonly:
false
10
{Integer}
stack_trace_limit number of stack frames to capture
- default:
10
- type:
Integer
- readonly:
false
false
{Boolean}
builtins_in_stack_traces show built-in functions in stack traces
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
disable_native_files disable builtin natives files
- default:
false
- type:
Boolean
- readonly:
false
true
{Boolean}
inline_new use fast inline allocation
- default:
true
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_codegen print name of functions for which code is generated
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace trace function calls
- default:
false
- type:
Boolean
- readonly:
false
true
{Boolean}
mask_constants_with_cookie use random jit cookie to mask large constants
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
lazy use lazy compilation
- default:
true
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_opt trace lazy optimization
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_opt_stats trace lazy optimization statistics
- default:
false
- type:
Boolean
- readonly:
false
true
{Boolean}
opt use adaptive optimizations
- default:
true
- type:
Boolean
- readonly:
false
false
{Boolean}
always_opt always try to optimize functions
- default:
false
- type:
Boolean
- readonly:
false
Note: not properly working below node: 0.10
- v8: 3.14
false
{Boolean}
always_osr always try to OSR functions
- default:
false
- type:
Boolean
- readonly:
false
OSR (On Stack Replacement) is used to convert a running function’s interpreter frame into a JIT’d frame – in the middle of that method.
Resources:
- Efficient and General On-Stack Replacement for Aggressive Program Specialization
- What the heck is OSR
- v8 source
Note: available starting with node: 0.10
- v8: 3.14
false
{Boolean}
prepare_always_opt prepare for turning on always opt
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_deopt trace optimize function deoptimization
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_stub_failures trace deoptimization of generated code stubs
- default:
false
- type:
Boolean
- readonly:
false
1024
{Integer}
min_preparse_length minimum length for automatic enable preparsing
- default:
1024
- type:
Integer
- readonly:
false
false
{Boolean}
always_full_compiler try to use the dedicated run-once backend for all code
- default:
false
- type:
Boolean
- readonly:
false
10
{Integer}
max_opt_count maximum number of optimization attempts before giving up.
- default:
10
- type:
Integer
- readonly:
false
true
{Boolean}
compilation_cache enable compilation cache
- default:
true
- type:
Boolean
- readonly:
false
The compilation cache keeps shared function infos for compiled scripts and evals. The shared function infos are looked up using the source string as the key. For regular expressions the compilation data is cached.
Enable/Disable is used by debugger to disable compilation cache during debugging to make sure new scripts are always
compiled, however both this flag and the enabled_
property need to be true
in order for the compilation cache to get
used.
Resources
true
{Boolean}
cache_prototype_transitions cache prototype transitions
- default:
true
- type:
Boolean
- readonly:
false
Resources:
1000
{Integer}
cpu_profiler_sampling_interval CPU profiler sampling interval in microseconds
- default:
1000
- type:
Integer
- readonly:
false
false
{Boolean}
trace_debug_json trace debugging JSON request/response
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_js_array_abuse trace out-of-bounds accesses to JS arrays
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_external_array_abuse trace out-of-bounds-accesses to external arrays
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_array_abuse trace out-of-bounds accesses to all arrays
- default:
false
- type:
Boolean
- readonly:
false
Implications
- trace_js_array_abuse
- trace_external_array_abuse
true
{Boolean}
debugger_auto_break automatically set the debug break flag when debugger commands are in the queue
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
enable_liveedit enable liveedit experimental feature
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
hard_abort abort by crashing
- default:
true
- type:
Boolean
- readonly:
false
984
{Integer}
stack_size default size of stack region v8 is allowed to use (in kBytes)
- default:
984
- type:
Integer
- readonly:
false
300
{Integer}
max_stack_trace_source_length maximum length of function source code printed in a stack trace.
- default:
300
- type:
Integer
- readonly:
false
false
{Boolean}
always_inline_smi_code always inline smi code in non-opt code
- default:
false
- type:
Boolean
- readonly:
false
0
{Integer}
max_new_space_size max size of the new generation (in kBytes)
- default:
0
- type:
Integer
- readonly:
false
0
{Integer}
max_old_space_size max size of the old generation (in Mbytes)
- default:
0
- type:
Integer
- readonly:
false
0
{Integer}
max_executable_size max size of executable memory (in Mbytes)
- default:
0
- type:
Integer
- readonly:
false
false
{Boolean}
gc_global always perform global GCs
- default:
false
- type:
Boolean
- readonly:
false
-1
{Integer}
gc_interval garbage collect after allocations
- default:
-1
- type:
Integer
- readonly:
false
false
{Boolean}
trace_gc print one trace line following each garbage collection
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_gc_nvp print one detailed trace line in name=value format after each garbage collection
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_gc_ignore_scavenger do not print trace line after scavenger collection
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
print_cumulative_gc_stat print cumulative GC statistics in name=value format on exit
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
print_max_heap_committed print statistics of the maximum memory committed for the heap in name=value format on exit
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_gc_verbose print more details following each garbage collection
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_fragmentation report fragmentation for old pointer and data pages
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_external_memory print amount of external allocated memory after each time it is adjusted.
- default:
false
- type:
Boolean
- readonly:
false
true
{Boolean}
collect_maps garbage collect maps from which no objects can be reached
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
weak_embedded_maps_in_optimized_code make maps embedded in optimized code weak
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
weak_embedded_objects_in_optimized_code make objects embedded in optimized code weak
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
flush_code flush code that we expect not to use again (during full gc)
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
flush_code_incrementally flush code that we expect not to use again (incrementally)
- default:
true
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_code_flushing trace code flushing progress
- default:
false
- type:
Boolean
- readonly:
false
true
{Boolean}
age_code track un-executed functions to age code and flush only old code (required for code flushing)
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
incremental_marking use incremental marking
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
incremental_marking_steps do incremental marking steps
- default:
true
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_incremental_marking trace progress of the incremental marking
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
track_gc_object_stats track object counts and memory usage
- default:
false
- type:
Boolean
- readonly:
false
true
{Boolean}
parallel_sweeping enable parallel sweeping
- default:
true
- type:
Boolean
- readonly:
false
false
{Boolean}
concurrent_sweeping enable concurrent sweeping
- default:
false
- type:
Boolean
- readonly:
false
Resources
Note: not available below node: 0.11
- v8: 3.25
0
{Integer}
sweeper_threads number of parallel and concurrent sweeping threads
- default:
0
- type:
Integer
- readonly:
false
false
{Boolean}
job_based_sweeping enable job based sweeping
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
heap_profiler_trace_objects Dump heap object allocations/movements/size_updates
- default:
false
- type:
Boolean
- readonly:
false
true
{Boolean}
use_idle_notification Use idle notification to reduce memory footprint.
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
use_ic use inline caching
- default:
true
- type:
Boolean
- readonly:
false
false
{Boolean}
native_code_counters generate extra code for manipulating stats counters
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
always_compact Perform compaction on every full GC
- default:
false
- type:
Boolean
- readonly:
false
true
{Boolean}
lazy_sweeping Use lazy sweeping for old pointer and data spaces
- default:
true
- type:
Boolean
- readonly:
false
false
{Boolean}
never_compact Never perform compaction on full GC - testing only
- default:
false
- type:
Boolean
- readonly:
false
true
{Boolean}
compact_code_space Compact code space on full non-incremental collections
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
incremental_code_compaction Compact code space on full incremental collections
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
cleanup_code_caches_at_gc Flush inline caches prior to mark compact collection and flush code caches in maps during mark compact cycle.
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
use_marking_progress_bar Use a progress bar to scan large objects in increments when incremental marking is active.
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
zap_code_space Zap free memory in code space with 0xCC while sweeping.
- default:
true
- type:
Boolean
- readonly:
false
0
{Integer}
random_seed Default seed for initializing random generator (0, the default, means to use system random).
- default:
0
- type:
Integer
- readonly:
false
true
{Boolean}
use_verbose_printer allows verbose printing
- default:
true
- type:
Boolean
- readonly:
false
false
{Boolean}
allow_natives_syntax allow natives syntax
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_parse trace parsing and preparsing
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_sim Trace simulator execution
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
debug_sim Enable debugging the simulator
- default:
false
- type:
Boolean
- readonly:
false
At this point this is only used inside the arm64 simulator.
Resources
Note: not available below node: 0.11
- v8: 3.25
false
{Boolean}
check_icache Check icache flushes in ARM and MIPS simulator
- default:
false
- type:
Boolean
- readonly:
false
0
{Integer}
stop_sim_at Simulator stop after x number of instructions
- default:
0
- type:
Integer
- readonly:
false
8
{Integer}
sim_stack_alignment Stack alingment in bytes in simulator (4 or 8, 8 is default)
- default:
8
- type:
Integer
- readonly:
false
2048
{Integer}
sim_stack_size Stack size of the ARM64 simulator in kBytes (default is 2 MB)
- default:
2048
- type:
Integer
- readonly:
false
true
{Boolean}
log_regs_modified When logging register values, only print modified registers.
- default:
true
- type:
Boolean
- readonly:
false
true
{Boolean}
log_colour When logging, try to use coloured output.
- default:
true
- type:
Boolean
- readonly:
false
false
{Boolean}
ignore_asm_unimplemented_break Don't break for ASM_UNIMPLEMENTED_BREAK macros.
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_sim_messages Trace simulator debug messages. Implied by --trace-sim.
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
stack_trace_on_illegal print stack trace when an illegal exception is thrown
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
abort_on_uncaught_exception abort program (dump core) when an uncaught exception is thrown
- default:
false
- type:
Boolean
- readonly:
false
true
{Boolean}
randomize_hashes randomize hashes to avoid predictable hash collisions (with snapshots this option cannot override the baked-in seed)
- default:
true
- type:
Boolean
- readonly:
false
0
{Integer}
hash_seed Fixed seed to use to hash property keys (0 means random)(with snapshots this option cannot override the baked-in seed)
- default:
0
- type:
Integer
- readonly:
false
false
{Boolean}
profile_deserialization Print the time it takes to deserialize the snapshot.
- default:
false
- type:
Boolean
- readonly:
false
true
{Boolean}
regexp_optimization generate optimized regexp code
- default:
true
- type:
Boolean
- readonly:
false
Hello, world!
{String}
testing_string_flag string-flag
- default:
Hello, world!
- type:
String
- readonly:
false
/tmp/serdes
{String}
testing_serialization_file file in which to serialize heap
- default:
/tmp/serdes
- type:
String
- readonly:
false
undefined
{String}
extra_code A filename with extra code to be included in the snapshot (mksnapshot only)
- default:
undefined
- type:
String
- readonly:
false
false
{Boolean}
profile_hydrogen_code_stub_compilation Print the time it takes to lazily compile hydrogen code stubs.
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
predictable enable predictable mode
- default:
false
- type:
Boolean
- readonly:
false
Negative implications
- concurrent_recompilation
- concurrent_osr
- concurrent_sweeping
- parallel_sweeping
false
{Boolean}
help Print usage message, including flags, on console
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
dump_counters Dump counters on exit
- default:
false
- type:
Boolean
- readonly:
false
map_counters `` {String}
Map counters to a file
- default: ``
- type:
String
- readonly:
false
true
{Boolean}
debug_compile_events Enable debugger compile events
- default:
true
- type:
Boolean
- readonly:
false
Resources
Note: disabled by default on WebOS
true
{Boolean}
debug_script_collected_events Enable debugger script collected events
- default:
true
- type:
Boolean
- readonly:
false
false
{Boolean}
gdbjit enable GDBJIT interface (disables compacting GC)
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
gdbjit_full enable GDBJIT interface for all code objects
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
gdbjit_dump dump elf objects with debug info to disk
- default:
false
- type:
Boolean
- readonly:
false
gdbjit_dump_filter `` {String}
dump only objects containing this substring
- default: ``
- type:
String
- readonly:
false
false
{Boolean}
force_marking_deque_overflows force overflows of marking deque by reducing it's size to 64 words
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
stress_compaction stress the GC compactor to flush out bugs (implies --force_marking_deque_overflows)
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
print_source pretty print source code
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
print_builtin_source pretty print source code for builtins
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
print_ast print source AST
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
print_builtin_ast print source AST for builtins
- default:
false
- type:
Boolean
- readonly:
true
stop_at `` {String}
function name where to insert a breakpoint
- default: ``
- type:
String
- readonly:
true
false
{Boolean}
trap_on_abort replace aborts by breakpoints
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
print_builtin_scopes print scopes for builtins
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
print_scopes print scopes
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
trace_contexts trace contexts operations
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
gc_greedy perform GC prior to some allocations
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
gc_verbose print stuff during garbage collection
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
heap_stats report heap statistics before and after GC
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
code_stats report code statistics after GC
- default:
false
- type:
Boolean
- readonly:
true
Resources
false
{Boolean}
verify_native_context_separation verify that code holds on to at most one native context after GC
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
print_handles report handles after GC
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
print_global_handles report global handles after GC
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
trace_ic trace inline cache state transitions
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
print_interfaces print interfaces
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
print_interface_details print interface inference details
- default:
false
- type:
Boolean
- readonly:
true
5
{Integer}
print_interface_depth depth for printing interfaces
- default:
5
- type:
Integer
- readonly:
true
false
{Boolean}
trace_normalization prints when objects are turned into dictionaries.
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
trace_lazy trace lazy compilation
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
collect_heap_spill_statistics report heap spill statistics along with heap_stats (requires heap_stats)
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
trace_isolates trace isolate state changes
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
regexp_possessive_quantifier enable possessive quantifier syntax for testing
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
trace_regexp_bytecodes trace regexp bytecode execution
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
trace_regexp_assembler trace regexp macro assembler calls.
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
log Minimal logging (no API, code, GC, suspect, or handles samples).
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
log_all Log all events to the log file.
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
log_runtime Activate runtime system %Log call.
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
log_api Log API events to the log file.
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
log_code Log code events to the log file without profiling.
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
log_gc Log heap samples on garbage collection for the hp2ps tool.
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
log_handles Log global handle events.
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
log_snapshot_positions log positions of (de)serialized objects in the snapshot.
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
log_suspect Log suspect operations.
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
prof Log statistical profiling information (implies --log-code).
- default:
false
- type:
Boolean
- readonly:
false
true
{Boolean}
prof_browser_mode Used with --prof, turns on browser-compatible mode for profiling.
- default:
true
- type:
Boolean
- readonly:
false
false
{Boolean}
log_regexp Log regular expression execution.
- default:
false
- type:
Boolean
- readonly:
false
v8.log
{String}
logfile Specify the name of the log file.
- default:
v8.log
- type:
String
- readonly:
false
true
{Boolean}
logfile_per_isolate Separate log files for each isolate.
- default:
true
- type:
Boolean
- readonly:
false
false
{Boolean}
ll_prof Enable low-level linux profiler.
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
perf_basic_prof Enable perf linux profiler (basic support).
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
perf_jit_prof Enable perf linux profiler (experimental annotate support).
- default:
false
- type:
Boolean
- readonly:
false
/tmp/__v8_gc__
{String}
gc_fake_mmap Specify the name of the file for fake gc mmap used in ll_prof
- default:
/tmp/__v8_gc__
- type:
String
- readonly:
false
false
{Boolean}
log_internal_timer_events Time internal events.
- default:
false
- type:
Boolean
- readonly:
false
Implications
- prof
false
{Boolean}
log_timer_events Time events including external callbacks.
- default:
false
- type:
Boolean
- readonly:
false
Implications
- log_internal_timer_events
false
{Boolean}
log_instruction_stats Log AArch64 instruction statistics.
- default:
false
- type:
Boolean
- readonly:
false
arm64_inst.csv
{String}
log_instruction_file AArch64 instruction statistics log file.
- default:
arm64_inst.csv
- type:
String
- readonly:
false
4194304
{Integer}
log_instruction_period AArch64 instruction statistics logging period.
- default:
4194304
- type:
Integer
- readonly:
false
false
{Boolean}
redirect_code_traces output deopt information and disassembly into file code--.asm
- default:
false
- type:
Boolean
- readonly:
false
undefined
{String}
redirect_code_traces_to output deopt information and disassembly into the given file
- default:
undefined
- type:
String
- readonly:
false
false
{Boolean}
hydrogen_track_positions track source code positions when building IR
- default:
false
- type:
Boolean
- readonly:
false
false
{Boolean}
trace_elements_transitions trace elements transitions
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
trace_creation_allocation_sites trace the creation of allocation sites
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
print_code_stubs print code stubs
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
test_secondary_stub_cache test secondary stub cache by disabling the primary one
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
test_primary_stub_cache test primary stub cache by disabling the secondary one
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
print_code print generated code
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
print_opt_code print optimized code
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
print_unopt_code print unoptimized code before printing optimized code based on it
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
print_code_verbose print more information for code
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
print_builtin_code print generated code for builtins
- default:
false
- type:
Boolean
- readonly:
true
false
{Boolean}
enable_ool_constant_pool enable use of out-of-line constant pools (ARM only)
- default:
false
- type:
Boolean
- readonly:
true