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      1 // Copyright 2012 the V8 project authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 // This file defines all of the flags.  It is separated into different section,
      6 // for Debug, Release, Logging and Profiling, etc.  To add a new flag, find the
      7 // correct section, and use one of the DEFINE_ macros, without a trailing ';'.
      8 //
      9 // This include does not have a guard, because it is a template-style include,
     10 // which can be included multiple times in different modes.  It expects to have
     11 // a mode defined before it's included.  The modes are FLAG_MODE_... below:
     12 
     13 #define DEFINE_IMPLICATION(whenflag, thenflag)              \
     14   DEFINE_VALUE_IMPLICATION(whenflag, thenflag, true)
     15 
     16 #define DEFINE_NEG_IMPLICATION(whenflag, thenflag)          \
     17   DEFINE_VALUE_IMPLICATION(whenflag, thenflag, false)
     18 
     19 #define DEFINE_NEG_NEG_IMPLICATION(whenflag, thenflag) \
     20   DEFINE_NEG_VALUE_IMPLICATION(whenflag, thenflag, false)
     21 
     22 // We want to declare the names of the variables for the header file.  Normally
     23 // this will just be an extern declaration, but for a readonly flag we let the
     24 // compiler make better optimizations by giving it the value.
     25 #if defined(FLAG_MODE_DECLARE)
     26 #define FLAG_FULL(ftype, ctype, nam, def, cmt) extern ctype FLAG_##nam;
     27 #define FLAG_READONLY(ftype, ctype, nam, def, cmt) \
     28   static ctype const FLAG_##nam = def;
     29 
     30 // We want to supply the actual storage and value for the flag variable in the
     31 // .cc file.  We only do this for writable flags.
     32 #elif defined(FLAG_MODE_DEFINE)
     33 #define FLAG_FULL(ftype, ctype, nam, def, cmt) ctype FLAG_##nam = def;
     34 
     35 // We need to define all of our default values so that the Flag structure can
     36 // access them by pointer.  These are just used internally inside of one .cc,
     37 // for MODE_META, so there is no impact on the flags interface.
     38 #elif defined(FLAG_MODE_DEFINE_DEFAULTS)
     39 #define FLAG_FULL(ftype, ctype, nam, def, cmt) \
     40   static ctype const FLAGDEFAULT_##nam = def;
     41 
     42 // We want to write entries into our meta data table, for internal parsing and
     43 // printing / etc in the flag parser code.  We only do this for writable flags.
     44 #elif defined(FLAG_MODE_META)
     45 #define FLAG_FULL(ftype, ctype, nam, def, cmt)                              \
     46   { Flag::TYPE_##ftype, #nam, &FLAG_##nam, &FLAGDEFAULT_##nam, cmt, false } \
     47   ,
     48 #define FLAG_ALIAS(ftype, ctype, alias, nam)                     \
     49   {                                                              \
     50     Flag::TYPE_##ftype, #alias, &FLAG_##nam, &FLAGDEFAULT_##nam, \
     51         "alias for --" #nam, false                               \
     52   }                                                              \
     53   ,
     54 
     55 // We produce the code to set flags when it is implied by another flag.
     56 #elif defined(FLAG_MODE_DEFINE_IMPLICATIONS)
     57 #define DEFINE_VALUE_IMPLICATION(whenflag, thenflag, value) \
     58   if (FLAG_##whenflag) FLAG_##thenflag = value;
     59 
     60 #define DEFINE_NEG_VALUE_IMPLICATION(whenflag, thenflag, value) \
     61   if (!FLAG_##whenflag) FLAG_##thenflag = value;
     62 
     63 #else
     64 #error No mode supplied when including flags.defs
     65 #endif
     66 
     67 // Dummy defines for modes where it is not relevant.
     68 #ifndef FLAG_FULL
     69 #define FLAG_FULL(ftype, ctype, nam, def, cmt)
     70 #endif
     71 
     72 #ifndef FLAG_READONLY
     73 #define FLAG_READONLY(ftype, ctype, nam, def, cmt)
     74 #endif
     75 
     76 #ifndef FLAG_ALIAS
     77 #define FLAG_ALIAS(ftype, ctype, alias, nam)
     78 #endif
     79 
     80 #ifndef DEFINE_VALUE_IMPLICATION
     81 #define DEFINE_VALUE_IMPLICATION(whenflag, thenflag, value)
     82 #endif
     83 
     84 #ifndef DEFINE_NEG_VALUE_IMPLICATION
     85 #define DEFINE_NEG_VALUE_IMPLICATION(whenflag, thenflag, value)
     86 #endif
     87 
     88 #define COMMA ,
     89 
     90 #ifdef FLAG_MODE_DECLARE
     91 // Structure used to hold a collection of arguments to the JavaScript code.
     92 struct JSArguments {
     93  public:
     94   inline const char*& operator[](int idx) const { return argv[idx]; }
     95   static JSArguments Create(int argc, const char** argv) {
     96     JSArguments args;
     97     args.argc = argc;
     98     args.argv = argv;
     99     return args;
    100   }
    101   int argc;
    102   const char** argv;
    103 };
    104 
    105 struct MaybeBoolFlag {
    106   static MaybeBoolFlag Create(bool has_value, bool value) {
    107     MaybeBoolFlag flag;
    108     flag.has_value = has_value;
    109     flag.value = value;
    110     return flag;
    111   }
    112   bool has_value;
    113   bool value;
    114 };
    115 #endif
    116 
    117 #ifdef DEBUG
    118 #define DEBUG_BOOL true
    119 #else
    120 #define DEBUG_BOOL false
    121 #endif
    122 #if (defined CAN_USE_VFP3_INSTRUCTIONS) || !(defined ARM_TEST_NO_FEATURE_PROBE)
    123 #define ENABLE_VFP3_DEFAULT true
    124 #else
    125 #define ENABLE_VFP3_DEFAULT false
    126 #endif
    127 #if (defined CAN_USE_ARMV7_INSTRUCTIONS) || !(defined ARM_TEST_NO_FEATURE_PROBE)
    128 #define ENABLE_ARMV7_DEFAULT true
    129 #else
    130 #define ENABLE_ARMV7_DEFAULT false
    131 #endif
    132 #if (defined CAN_USE_ARMV8_INSTRUCTIONS) || !(defined ARM_TEST_NO_FEATURE_PROBE)
    133 #define ENABLE_ARMV8_DEFAULT true
    134 #else
    135 #define ENABLE_ARMV8_DEFAULT false
    136 #endif
    137 #if (defined CAN_USE_VFP32DREGS) || !(defined ARM_TEST_NO_FEATURE_PROBE)
    138 #define ENABLE_32DREGS_DEFAULT true
    139 #else
    140 #define ENABLE_32DREGS_DEFAULT false
    141 #endif
    142 #if (defined CAN_USE_NEON) || !(defined ARM_TEST_NO_FEATURE_PROBE)
    143 # define ENABLE_NEON_DEFAULT true
    144 #else
    145 # define ENABLE_NEON_DEFAULT false
    146 #endif
    147 #ifdef V8_OS_WIN
    148 # define ENABLE_LOG_COLOUR false
    149 #else
    150 # define ENABLE_LOG_COLOUR true
    151 #endif
    152 
    153 #define DEFINE_BOOL(nam, def, cmt) FLAG(BOOL, bool, nam, def, cmt)
    154 #define DEFINE_BOOL_READONLY(nam, def, cmt) \
    155   FLAG_READONLY(BOOL, bool, nam, def, cmt)
    156 #define DEFINE_MAYBE_BOOL(nam, cmt) \
    157   FLAG(MAYBE_BOOL, MaybeBoolFlag, nam, {false COMMA false}, cmt)
    158 #define DEFINE_INT(nam, def, cmt) FLAG(INT, int, nam, def, cmt)
    159 #define DEFINE_FLOAT(nam, def, cmt) FLAG(FLOAT, double, nam, def, cmt)
    160 #define DEFINE_STRING(nam, def, cmt) FLAG(STRING, const char*, nam, def, cmt)
    161 #define DEFINE_ARGS(nam, cmt) FLAG(ARGS, JSArguments, nam, {0 COMMA NULL}, cmt)
    162 
    163 #define DEFINE_ALIAS_BOOL(alias, nam) FLAG_ALIAS(BOOL, bool, alias, nam)
    164 #define DEFINE_ALIAS_INT(alias, nam) FLAG_ALIAS(INT, int, alias, nam)
    165 #define DEFINE_ALIAS_FLOAT(alias, nam) FLAG_ALIAS(FLOAT, double, alias, nam)
    166 #define DEFINE_ALIAS_STRING(alias, nam) \
    167   FLAG_ALIAS(STRING, const char*, alias, nam)
    168 #define DEFINE_ALIAS_ARGS(alias, nam) FLAG_ALIAS(ARGS, JSArguments, alias, nam)
    169 
    170 //
    171 // Flags in all modes.
    172 //
    173 #define FLAG FLAG_FULL
    174 
    175 DEFINE_BOOL(experimental_extras, false,
    176             "enable code compiled in via v8_experimental_extra_library_files")
    177 
    178 // Flags for language modes and experimental language features.
    179 DEFINE_BOOL(use_strict, false, "enforce strict mode")
    180 
    181 DEFINE_BOOL(es_staging, false,
    182             "enable test-worthy harmony features (for internal use only)")
    183 DEFINE_BOOL(harmony, false, "enable all completed harmony features")
    184 DEFINE_BOOL(harmony_shipping, true, "enable all shipped harmony features")
    185 DEFINE_IMPLICATION(es_staging, harmony)
    186 
    187 DEFINE_BOOL(promise_extra, false, "additional V8 Promise functions")
    188 // Removing extra Promise functions is shipped
    189 DEFINE_NEG_VALUE_IMPLICATION(harmony_shipping, promise_extra, true)
    190 
    191 DEFINE_BOOL(intl_extra, false, "additional V8 Intl functions")
    192 // Removing extra Intl functions is shipped
    193 DEFINE_NEG_VALUE_IMPLICATION(harmony_shipping, intl_extra, true)
    194 
    195 // Activate on ClusterFuzz.
    196 DEFINE_IMPLICATION(es_staging, harmony_regexp_lookbehind)
    197 DEFINE_IMPLICATION(es_staging, move_object_start)
    198 
    199 // Features that are still work in progress (behind individual flags).
    200 #define HARMONY_INPROGRESS(V)                                           \
    201   V(harmony_array_prototype_values, "harmony Array.prototype.values")   \
    202   V(harmony_function_sent, "harmony function.sent")                     \
    203   V(harmony_sharedarraybuffer, "harmony sharedarraybuffer")             \
    204   V(harmony_simd, "harmony simd")                                       \
    205   V(harmony_explicit_tailcalls, "harmony explicit tail calls")          \
    206   V(harmony_do_expressions, "harmony do-expressions")                   \
    207   V(harmony_restrictive_generators,                                     \
    208     "harmony restrictions on generator declarations")                   \
    209   V(harmony_regexp_named_captures, "harmony regexp named captures")     \
    210   V(harmony_regexp_property, "harmony unicode regexp property classes") \
    211   V(harmony_for_in, "harmony for-in syntax")
    212 
    213 // Features that are complete (but still behind --harmony/es-staging flag).
    214 #define HARMONY_STAGED_BASE(V)                                               \
    215   V(harmony_regexp_lookbehind, "harmony regexp lookbehind")                  \
    216   V(harmony_tailcalls, "harmony tail calls")                                 \
    217   V(harmony_object_values_entries, "harmony Object.values / Object.entries") \
    218   V(harmony_object_own_property_descriptors,                                 \
    219     "harmony Object.getOwnPropertyDescriptors()")                            \
    220   V(harmony_async_await, "harmony async-await")                              \
    221   V(harmony_string_padding, "harmony String-padding methods")
    222 
    223 #ifdef V8_I18N_SUPPORT
    224 #define HARMONY_STAGED(V) \
    225   HARMONY_STAGED_BASE(V)  \
    226   V(icu_case_mapping, "case mapping with ICU rather than Unibrow")
    227 #else
    228 #define HARMONY_STAGED(V) HARMONY_STAGED_BASE(V)
    229 #endif
    230 
    231 // Features that are shipping (turned on by default, but internal flag remains).
    232 #define HARMONY_SHIPPING(V)                                           \
    233   V(harmony_restrictive_declarations,                                 \
    234     "harmony limitations on sloppy mode function declarations")       \
    235   V(harmony_exponentiation_operator, "harmony exponentiation operator `**`")
    236 
    237 // Once a shipping feature has proved stable in the wild, it will be dropped
    238 // from HARMONY_SHIPPING, all occurrences of the FLAG_ variable are removed,
    239 // and associated tests are moved from the harmony directory to the appropriate
    240 // esN directory.
    241 
    242 
    243 #define FLAG_INPROGRESS_FEATURES(id, description) \
    244   DEFINE_BOOL(id, false, "enable " #description " (in progress)")
    245 HARMONY_INPROGRESS(FLAG_INPROGRESS_FEATURES)
    246 #undef FLAG_INPROGRESS_FEATURES
    247 
    248 #define FLAG_STAGED_FEATURES(id, description) \
    249   DEFINE_BOOL(id, false, "enable " #description) \
    250   DEFINE_IMPLICATION(harmony, id)
    251 HARMONY_STAGED(FLAG_STAGED_FEATURES)
    252 #undef FLAG_STAGED_FEATURES
    253 
    254 #define FLAG_SHIPPING_FEATURES(id, description) \
    255   DEFINE_BOOL(id, true, "enable " #description) \
    256   DEFINE_NEG_NEG_IMPLICATION(harmony_shipping, id)
    257 HARMONY_SHIPPING(FLAG_SHIPPING_FEATURES)
    258 #undef FLAG_SHIPPING_FEATURES
    259 
    260 // Flags for experimental implementation features.
    261 DEFINE_BOOL(compiled_keyed_generic_loads, false,
    262             "use optimizing compiler to generate keyed generic load stubs")
    263 DEFINE_BOOL(allocation_site_pretenuring, true,
    264             "pretenure with allocation sites")
    265 DEFINE_BOOL(page_promotion, true, "promote pages based on utilization")
    266 DEFINE_INT(page_promotion_threshold, 70,
    267            "min percentage of live bytes on a page to enable fast evacuation")
    268 DEFINE_BOOL(trace_pretenuring, false,
    269             "trace pretenuring decisions of HAllocate instructions")
    270 DEFINE_BOOL(trace_pretenuring_statistics, false,
    271             "trace allocation site pretenuring statistics")
    272 DEFINE_BOOL(track_fields, true, "track fields with only smi values")
    273 DEFINE_BOOL(track_double_fields, true, "track fields with double values")
    274 DEFINE_BOOL(track_heap_object_fields, true, "track fields with heap values")
    275 DEFINE_BOOL(track_computed_fields, true, "track computed boilerplate fields")
    276 DEFINE_IMPLICATION(track_double_fields, track_fields)
    277 DEFINE_IMPLICATION(track_heap_object_fields, track_fields)
    278 DEFINE_IMPLICATION(track_computed_fields, track_fields)
    279 DEFINE_BOOL(track_field_types, true, "track field types")
    280 DEFINE_IMPLICATION(track_field_types, track_fields)
    281 DEFINE_IMPLICATION(track_field_types, track_heap_object_fields)
    282 DEFINE_BOOL(smi_binop, true, "support smi representation in binary operations")
    283 
    284 // Flags for optimization types.
    285 DEFINE_BOOL(optimize_for_size, false,
    286             "Enables optimizations which favor memory size over execution "
    287             "speed")
    288 
    289 DEFINE_VALUE_IMPLICATION(optimize_for_size, max_semi_space_size, 1)
    290 
    291 // Flags for data representation optimizations
    292 DEFINE_BOOL(unbox_double_arrays, true, "automatically unbox arrays of doubles")
    293 DEFINE_BOOL(string_slices, true, "use string slices")
    294 
    295 // Flags for Ignition.
    296 DEFINE_BOOL(ignition, false, "use ignition interpreter")
    297 DEFINE_BOOL(ignition_eager, false, "eagerly compile and parse with ignition")
    298 DEFINE_BOOL(ignition_generators, true,
    299             "enable experimental ignition support for generators")
    300 DEFINE_STRING(ignition_filter, "*", "filter for ignition interpreter")
    301 DEFINE_BOOL(ignition_deadcode, true,
    302             "use ignition dead code elimination optimizer")
    303 DEFINE_BOOL(ignition_peephole, true, "use ignition peephole optimizer")
    304 DEFINE_BOOL(ignition_reo, true, "use ignition register equivalence optimizer")
    305 DEFINE_BOOL(ignition_filter_expression_positions, true,
    306             "filter expression positions before the bytecode pipeline")
    307 DEFINE_BOOL(print_bytecode, false,
    308             "print bytecode generated by ignition interpreter")
    309 DEFINE_BOOL(trace_ignition, false,
    310             "trace the bytecodes executed by the ignition interpreter")
    311 DEFINE_BOOL(trace_ignition_codegen, false,
    312             "trace the codegen of ignition interpreter bytecode handlers")
    313 DEFINE_BOOL(trace_ignition_dispatches, false,
    314             "traces the dispatches to bytecode handlers by the ignition "
    315             "interpreter")
    316 DEFINE_STRING(trace_ignition_dispatches_output_file, nullptr,
    317               "the file to which the bytecode handler dispatch table is "
    318               "written (by default, the table is not written to a file)")
    319 
    320 // Flags for Crankshaft.
    321 DEFINE_BOOL(crankshaft, true, "use crankshaft")
    322 DEFINE_STRING(hydrogen_filter, "*", "optimization filter")
    323 DEFINE_BOOL(use_gvn, true, "use hydrogen global value numbering")
    324 DEFINE_INT(gvn_iterations, 3, "maximum number of GVN fix-point iterations")
    325 DEFINE_BOOL(use_canonicalizing, true, "use hydrogen instruction canonicalizing")
    326 DEFINE_BOOL(use_inlining, true, "use function inlining")
    327 DEFINE_BOOL(use_escape_analysis, true, "use hydrogen escape analysis")
    328 DEFINE_BOOL(use_allocation_folding, true, "use allocation folding")
    329 DEFINE_BOOL(use_local_allocation_folding, false, "only fold in basic blocks")
    330 DEFINE_BOOL(use_write_barrier_elimination, true,
    331             "eliminate write barriers targeting allocations in optimized code")
    332 DEFINE_INT(max_inlining_levels, 5, "maximum number of inlining levels")
    333 DEFINE_INT(max_inlined_source_size, 600,
    334            "maximum source size in bytes considered for a single inlining")
    335 DEFINE_INT(max_inlined_nodes, 196,
    336            "maximum number of AST nodes considered for a single inlining")
    337 DEFINE_INT(max_inlined_nodes_cumulative, 400,
    338            "maximum cumulative number of AST nodes considered for inlining")
    339 DEFINE_BOOL(loop_invariant_code_motion, true, "loop invariant code motion")
    340 DEFINE_BOOL(fast_math, true, "faster (but maybe less accurate) math functions")
    341 DEFINE_BOOL(collect_megamorphic_maps_from_stub_cache, false,
    342             "crankshaft harvests type feedback from stub cache")
    343 DEFINE_BOOL(hydrogen_stats, false, "print statistics for hydrogen")
    344 DEFINE_BOOL(trace_check_elimination, false, "trace check elimination phase")
    345 DEFINE_BOOL(trace_environment_liveness, false,
    346             "trace liveness of local variable slots")
    347 DEFINE_BOOL(trace_hydrogen, false, "trace generated hydrogen to file")
    348 DEFINE_STRING(trace_hydrogen_filter, "*", "hydrogen tracing filter")
    349 DEFINE_BOOL(trace_hydrogen_stubs, false, "trace generated hydrogen for stubs")
    350 DEFINE_STRING(trace_hydrogen_file, NULL, "trace hydrogen to given file name")
    351 DEFINE_STRING(trace_phase, "HLZ", "trace generated IR for specified phases")
    352 DEFINE_BOOL(trace_inlining, false, "trace inlining decisions")
    353 DEFINE_BOOL(trace_load_elimination, false, "trace load elimination")
    354 DEFINE_BOOL(trace_store_elimination, false, "trace store elimination")
    355 DEFINE_BOOL(trace_alloc, false, "trace register allocator")
    356 DEFINE_BOOL(trace_all_uses, false, "trace all use positions")
    357 DEFINE_BOOL(trace_range, false, "trace range analysis")
    358 DEFINE_BOOL(trace_gvn, false, "trace global value numbering")
    359 DEFINE_BOOL(trace_representation, false, "trace representation types")
    360 DEFINE_BOOL(trace_removable_simulates, false, "trace removable simulates")
    361 DEFINE_BOOL(trace_escape_analysis, false, "trace hydrogen escape analysis")
    362 DEFINE_BOOL(trace_allocation_folding, false, "trace allocation folding")
    363 DEFINE_BOOL(trace_track_allocation_sites, false,
    364             "trace the tracking of allocation sites")
    365 DEFINE_BOOL(trace_migration, false, "trace object migration")
    366 DEFINE_BOOL(trace_generalization, false, "trace map generalization")
    367 DEFINE_BOOL(stress_pointer_maps, false, "pointer map for every instruction")
    368 DEFINE_BOOL(stress_environments, false, "environment for every instruction")
    369 DEFINE_INT(deopt_every_n_times, 0,
    370            "deoptimize every n times a deopt point is passed")
    371 DEFINE_INT(deopt_every_n_garbage_collections, 0,
    372            "deoptimize every n garbage collections")
    373 DEFINE_BOOL(print_deopt_stress, false, "print number of possible deopt points")
    374 DEFINE_BOOL(trap_on_deopt, false, "put a break point before deoptimizing")
    375 DEFINE_BOOL(trap_on_stub_deopt, false,
    376             "put a break point before deoptimizing a stub")
    377 DEFINE_BOOL(deoptimize_uncommon_cases, true, "deoptimize uncommon cases")
    378 DEFINE_BOOL(polymorphic_inlining, true, "polymorphic inlining")
    379 DEFINE_BOOL(use_osr, true, "use on-stack replacement")
    380 DEFINE_BOOL(array_bounds_checks_elimination, true,
    381             "perform array bounds checks elimination")
    382 DEFINE_BOOL(trace_bce, false, "trace array bounds check elimination")
    383 DEFINE_BOOL(array_index_dehoisting, true, "perform array index dehoisting")
    384 DEFINE_BOOL(analyze_environment_liveness, true,
    385             "analyze liveness of environment slots and zap dead values")
    386 DEFINE_BOOL(load_elimination, true, "use load elimination")
    387 DEFINE_BOOL(check_elimination, true, "use check elimination")
    388 DEFINE_BOOL(store_elimination, false, "use store elimination")
    389 DEFINE_BOOL(dead_code_elimination, true, "use dead code elimination")
    390 DEFINE_BOOL(fold_constants, true, "use constant folding")
    391 DEFINE_BOOL(trace_dead_code_elimination, false, "trace dead code elimination")
    392 DEFINE_BOOL(unreachable_code_elimination, true, "eliminate unreachable code")
    393 DEFINE_BOOL(trace_osr, false, "trace on-stack replacement")
    394 DEFINE_INT(stress_runs, 0, "number of stress runs")
    395 DEFINE_BOOL(lookup_sample_by_shared, true,
    396             "when picking a function to optimize, watch for shared function "
    397             "info, not JSFunction itself")
    398 DEFINE_BOOL(flush_optimized_code_cache, false,
    399             "flushes the cache of optimized code for closures on every GC")
    400 DEFINE_BOOL(inline_construct, true, "inline constructor calls")
    401 DEFINE_BOOL(inline_arguments, true, "inline functions with arguments object")
    402 DEFINE_BOOL(inline_accessors, true, "inline JavaScript accessors")
    403 DEFINE_INT(escape_analysis_iterations, 2,
    404            "maximum number of escape analysis fix-point iterations")
    405 
    406 DEFINE_BOOL(concurrent_recompilation, true,
    407             "optimizing hot functions asynchronously on a separate thread")
    408 DEFINE_BOOL(trace_concurrent_recompilation, false,
    409             "track concurrent recompilation")
    410 DEFINE_INT(concurrent_recompilation_queue_length, 8,
    411            "the length of the concurrent compilation queue")
    412 DEFINE_INT(concurrent_recompilation_delay, 0,
    413            "artificial compilation delay in ms")
    414 DEFINE_BOOL(block_concurrent_recompilation, false,
    415             "block queued jobs until released")
    416 
    417 DEFINE_BOOL(omit_map_checks_for_leaf_maps, true,
    418             "do not emit check maps for constant values that have a leaf map, "
    419             "deoptimize the optimized code if the layout of the maps changes.")
    420 
    421 // Flags for TurboFan.
    422 DEFINE_BOOL(turbo, false, "enable TurboFan compiler")
    423 DEFINE_IMPLICATION(turbo, turbo_asm_deoptimization)
    424 DEFINE_IMPLICATION(turbo, turbo_type_feedback)
    425 DEFINE_BOOL(turbo_shipping, true, "enable TurboFan compiler on subset")
    426 DEFINE_BOOL(turbo_from_bytecode, false, "enable building graphs from bytecode")
    427 DEFINE_BOOL(turbo_sp_frame_access, false,
    428             "use stack pointer-relative access to frame wherever possible")
    429 DEFINE_BOOL(turbo_preprocess_ranges, true,
    430             "run pre-register allocation heuristics")
    431 DEFINE_BOOL(turbo_loop_stackcheck, true, "enable stack checks in loops")
    432 DEFINE_STRING(turbo_filter, "~~", "optimization filter for TurboFan compiler")
    433 DEFINE_BOOL(trace_turbo, false, "trace generated TurboFan IR")
    434 DEFINE_BOOL(trace_turbo_graph, false, "trace generated TurboFan graphs")
    435 DEFINE_IMPLICATION(trace_turbo_graph, trace_turbo)
    436 DEFINE_STRING(trace_turbo_cfg_file, NULL,
    437               "trace turbo cfg graph (for C1 visualizer) to a given file name")
    438 DEFINE_BOOL(trace_turbo_types, true, "trace TurboFan's types")
    439 DEFINE_BOOL(trace_turbo_scheduler, false, "trace TurboFan's scheduler")
    440 DEFINE_BOOL(trace_turbo_reduction, false, "trace TurboFan's various reducers")
    441 DEFINE_BOOL(trace_turbo_jt, false, "trace TurboFan's jump threading")
    442 DEFINE_BOOL(trace_turbo_ceq, false, "trace TurboFan's control equivalence")
    443 DEFINE_BOOL(turbo_asm, true, "enable TurboFan for asm.js code")
    444 DEFINE_BOOL(turbo_asm_deoptimization, false,
    445             "enable deoptimization in TurboFan for asm.js code")
    446 DEFINE_BOOL(turbo_verify, DEBUG_BOOL, "verify TurboFan graphs at each phase")
    447 DEFINE_BOOL(turbo_stats, false, "print TurboFan statistics")
    448 DEFINE_BOOL(turbo_stats_nvp, false,
    449             "print TurboFan statistics in machine-readable format")
    450 DEFINE_BOOL(turbo_splitting, true, "split nodes during scheduling in TurboFan")
    451 DEFINE_BOOL(turbo_type_feedback, false,
    452             "use typed feedback for representation inference in Turbofan")
    453 DEFINE_BOOL(turbo_source_positions, false,
    454             "track source code positions when building TurboFan IR")
    455 DEFINE_IMPLICATION(trace_turbo, turbo_source_positions)
    456 DEFINE_BOOL(function_context_specialization, false,
    457             "enable function context specialization in TurboFan")
    458 DEFINE_BOOL(native_context_specialization, true,
    459             "enable native context specialization in TurboFan")
    460 DEFINE_BOOL(turbo_inlining, true, "enable inlining in TurboFan")
    461 DEFINE_BOOL(trace_turbo_inlining, false, "trace TurboFan inlining")
    462 DEFINE_BOOL(loop_assignment_analysis, true, "perform loop assignment analysis")
    463 DEFINE_BOOL(turbo_profiling, false, "enable profiling in TurboFan")
    464 DEFINE_BOOL(turbo_verify_allocation, DEBUG_BOOL,
    465             "verify register allocation in TurboFan")
    466 DEFINE_BOOL(turbo_move_optimization, true, "optimize gap moves in TurboFan")
    467 DEFINE_BOOL(turbo_jt, true, "enable jump threading in TurboFan")
    468 DEFINE_BOOL(turbo_stress_loop_peeling, false,
    469             "stress loop peeling optimization")
    470 DEFINE_BOOL(turbo_cf_optimization, true, "optimize control flow in TurboFan")
    471 DEFINE_BOOL(turbo_frame_elision, true, "elide frames in TurboFan")
    472 DEFINE_BOOL(turbo_cache_shared_code, true, "cache context-independent code")
    473 DEFINE_BOOL(turbo_preserve_shared_code, false, "keep context-independent code")
    474 DEFINE_BOOL(turbo_escape, false, "enable escape analysis")
    475 DEFINE_BOOL(turbo_instruction_scheduling, false,
    476             "enable instruction scheduling in TurboFan")
    477 DEFINE_BOOL(turbo_stress_instruction_scheduling, false,
    478             "randomly schedule instructions to stress dependency tracking")
    479 DEFINE_BOOL(turbo_store_elimination, false,
    480             "enable store-store elimination in TurboFan")
    481 
    482 // Flags for native WebAssembly.
    483 DEFINE_BOOL(expose_wasm, false, "expose WASM interface to JavaScript")
    484 DEFINE_INT(wasm_num_compilation_tasks, 10,
    485            "number of parallel compilation tasks for wasm")
    486 DEFINE_BOOL(trace_wasm_encoder, false, "trace encoding of wasm code")
    487 DEFINE_BOOL(trace_wasm_decoder, false, "trace decoding of wasm code")
    488 DEFINE_BOOL(trace_wasm_decode_time, false, "trace decoding time of wasm code")
    489 DEFINE_BOOL(trace_wasm_compiler, false, "trace compiling of wasm code")
    490 DEFINE_BOOL(trace_wasm_interpreter, false, "trace interpretation of wasm code")
    491 DEFINE_INT(trace_wasm_ast_start, 0,
    492            "start function for WASM AST trace (inclusive)")
    493 DEFINE_INT(trace_wasm_ast_end, 0, "end function for WASM AST trace (exclusive)")
    494 DEFINE_INT(skip_compiling_wasm_funcs, 0, "start compiling at function N")
    495 DEFINE_BOOL(wasm_break_on_decoder_error, false,
    496             "debug break when wasm decoder encounters an error")
    497 DEFINE_BOOL(wasm_loop_assignment_analysis, true,
    498             "perform loop assignment analysis for WASM")
    499 
    500 DEFINE_BOOL(validate_asm, false, "validate asm.js modules before compiling")
    501 DEFINE_BOOL(enable_simd_asmjs, false, "enable SIMD.js in asm.js stdlib")
    502 
    503 DEFINE_BOOL(dump_wasm_module, false, "dump WASM module bytes")
    504 DEFINE_STRING(dump_wasm_module_path, NULL, "directory to dump wasm modules to")
    505 DEFINE_BOOL(print_wasm_code_size, false,
    506             "print the generated code size for each wasm module")
    507 
    508 DEFINE_INT(typed_array_max_size_in_heap, 64,
    509            "threshold for in-heap typed array")
    510 
    511 DEFINE_BOOL(wasm_jit_prototype, false,
    512             "enable experimental wasm runtime dynamic code generation")
    513 
    514 // Profiler flags.
    515 DEFINE_INT(frame_count, 1, "number of stack frames inspected by the profiler")
    516 // 0x1800 fits in the immediate field of an ARM instruction.
    517 DEFINE_INT(interrupt_budget, 0x1800,
    518            "execution budget before interrupt is triggered")
    519 DEFINE_INT(type_info_threshold, 25,
    520            "percentage of ICs that must have type info to allow optimization")
    521 DEFINE_INT(generic_ic_threshold, 30,
    522            "max percentage of megamorphic/generic ICs to allow optimization")
    523 DEFINE_INT(self_opt_count, 130, "call count before self-optimization")
    524 
    525 DEFINE_BOOL(trace_opt_verbose, false, "extra verbose compilation tracing")
    526 DEFINE_IMPLICATION(trace_opt_verbose, trace_opt)
    527 
    528 // assembler-ia32.cc / assembler-arm.cc / assembler-x64.cc
    529 DEFINE_BOOL(debug_code, false, "generate extra code (assertions) for debugging")
    530 DEFINE_BOOL(code_comments, false, "emit comments in code disassembly")
    531 DEFINE_BOOL(enable_sse3, true, "enable use of SSE3 instructions if available")
    532 DEFINE_BOOL(enable_sse4_1, true,
    533             "enable use of SSE4.1 instructions if available")
    534 DEFINE_BOOL(enable_sahf, true,
    535             "enable use of SAHF instruction if available (X64 only)")
    536 DEFINE_BOOL(enable_avx, true, "enable use of AVX instructions if available")
    537 DEFINE_BOOL(enable_fma3, true, "enable use of FMA3 instructions if available")
    538 DEFINE_BOOL(enable_bmi1, true, "enable use of BMI1 instructions if available")
    539 DEFINE_BOOL(enable_bmi2, true, "enable use of BMI2 instructions if available")
    540 DEFINE_BOOL(enable_lzcnt, true, "enable use of LZCNT instruction if available")
    541 DEFINE_BOOL(enable_popcnt, true,
    542             "enable use of POPCNT instruction if available")
    543 DEFINE_BOOL(enable_vfp3, ENABLE_VFP3_DEFAULT,
    544             "enable use of VFP3 instructions if available")
    545 DEFINE_BOOL(enable_armv7, ENABLE_ARMV7_DEFAULT,
    546             "enable use of ARMv7 instructions if available (ARM only)")
    547 DEFINE_BOOL(enable_armv8, ENABLE_ARMV8_DEFAULT,
    548             "enable use of ARMv8 instructions if available (ARM 32-bit only)")
    549 DEFINE_BOOL(enable_neon, ENABLE_NEON_DEFAULT,
    550             "enable use of NEON instructions if available (ARM only)")
    551 DEFINE_BOOL(enable_sudiv, true,
    552             "enable use of SDIV and UDIV instructions if available (ARM only)")
    553 DEFINE_BOOL(enable_movw_movt, false,
    554             "enable loading 32-bit constant by means of movw/movt "
    555             "instruction pairs (ARM only)")
    556 DEFINE_BOOL(enable_unaligned_accesses, true,
    557             "enable unaligned accesses for ARMv7 (ARM only)")
    558 DEFINE_BOOL(enable_32dregs, ENABLE_32DREGS_DEFAULT,
    559             "enable use of d16-d31 registers on ARM - this requires VFP3")
    560 DEFINE_BOOL(enable_vldr_imm, false,
    561             "enable use of constant pools for double immediate (ARM only)")
    562 DEFINE_BOOL(force_long_branches, false,
    563             "force all emitted branches to be in long mode (MIPS/PPC only)")
    564 DEFINE_STRING(mcpu, "auto", "enable optimization for specific cpu")
    565 
    566 DEFINE_IMPLICATION(enable_armv8, enable_vfp3)
    567 DEFINE_IMPLICATION(enable_armv8, enable_neon)
    568 DEFINE_IMPLICATION(enable_armv8, enable_32dregs)
    569 DEFINE_IMPLICATION(enable_armv8, enable_sudiv)
    570 
    571 // bootstrapper.cc
    572 DEFINE_STRING(expose_natives_as, NULL, "expose natives in global object")
    573 DEFINE_STRING(expose_debug_as, NULL, "expose debug in global object")
    574 DEFINE_BOOL(expose_free_buffer, false, "expose freeBuffer extension")
    575 DEFINE_BOOL(expose_gc, false, "expose gc extension")
    576 DEFINE_STRING(expose_gc_as, NULL,
    577               "expose gc extension under the specified name")
    578 DEFINE_IMPLICATION(expose_gc_as, expose_gc)
    579 DEFINE_BOOL(expose_externalize_string, false,
    580             "expose externalize string extension")
    581 DEFINE_BOOL(expose_trigger_failure, false, "expose trigger-failure extension")
    582 DEFINE_INT(stack_trace_limit, 10, "number of stack frames to capture")
    583 DEFINE_BOOL(builtins_in_stack_traces, false,
    584             "show built-in functions in stack traces")
    585 DEFINE_BOOL(disable_native_files, false, "disable builtin natives files")
    586 
    587 // builtins-ia32.cc
    588 DEFINE_BOOL(inline_new, true, "use fast inline allocation")
    589 
    590 // codegen-ia32.cc / codegen-arm.cc
    591 DEFINE_BOOL(trace_codegen, false,
    592             "print name of functions for which code is generated")
    593 DEFINE_BOOL(trace, false, "trace function calls")
    594 DEFINE_BOOL(mask_constants_with_cookie, true,
    595             "use random jit cookie to mask large constants")
    596 
    597 // codegen.cc
    598 DEFINE_BOOL(lazy, true, "use lazy compilation")
    599 DEFINE_BOOL(trace_opt, false, "trace lazy optimization")
    600 DEFINE_BOOL(trace_opt_stats, false, "trace lazy optimization statistics")
    601 DEFINE_BOOL(trace_file_names, false,
    602             "include file names in trace-opt/trace-deopt output")
    603 DEFINE_BOOL(opt, true, "use adaptive optimizations")
    604 DEFINE_BOOL(always_opt, false, "always try to optimize functions")
    605 DEFINE_BOOL(always_osr, false, "always try to OSR functions")
    606 DEFINE_BOOL(prepare_always_opt, false, "prepare for turning on always opt")
    607 DEFINE_BOOL(trace_deopt, false, "trace optimize function deoptimization")
    608 DEFINE_BOOL(trace_stub_failures, false,
    609             "trace deoptimization of generated code stubs")
    610 
    611 DEFINE_BOOL(serialize_toplevel, true, "enable caching of toplevel scripts")
    612 DEFINE_BOOL(serialize_eager, false, "compile eagerly when caching scripts")
    613 DEFINE_BOOL(serialize_age_code, false, "pre age code in the code cache")
    614 DEFINE_BOOL(trace_serializer, false, "print code serializer trace")
    615 
    616 // compiler.cc
    617 DEFINE_INT(min_preparse_length, 1024,
    618            "minimum length for automatic enable preparsing")
    619 DEFINE_INT(max_opt_count, 10,
    620            "maximum number of optimization attempts before giving up.")
    621 
    622 // compilation-cache.cc
    623 DEFINE_BOOL(compilation_cache, true, "enable compilation cache")
    624 
    625 DEFINE_BOOL(cache_prototype_transitions, true, "cache prototype transitions")
    626 
    627 // cpu-profiler.cc
    628 DEFINE_INT(cpu_profiler_sampling_interval, 1000,
    629            "CPU profiler sampling interval in microseconds")
    630 
    631 // Array abuse tracing
    632 DEFINE_BOOL(trace_js_array_abuse, false,
    633             "trace out-of-bounds accesses to JS arrays")
    634 DEFINE_BOOL(trace_external_array_abuse, false,
    635             "trace out-of-bounds-accesses to external arrays")
    636 DEFINE_BOOL(trace_array_abuse, false,
    637             "trace out-of-bounds accesses to all arrays")
    638 DEFINE_IMPLICATION(trace_array_abuse, trace_js_array_abuse)
    639 DEFINE_IMPLICATION(trace_array_abuse, trace_external_array_abuse)
    640 
    641 // debugger
    642 DEFINE_BOOL(trace_debug_json, false, "trace debugging JSON request/response")
    643 DEFINE_BOOL(enable_liveedit, true, "enable liveedit experimental feature")
    644 DEFINE_BOOL(hard_abort, true, "abort by crashing")
    645 
    646 // execution.cc
    647 DEFINE_INT(stack_size, V8_DEFAULT_STACK_SIZE_KB,
    648            "default size of stack region v8 is allowed to use (in kBytes)")
    649 
    650 // frames.cc
    651 DEFINE_INT(max_stack_trace_source_length, 300,
    652            "maximum length of function source code printed in a stack trace.")
    653 
    654 // full-codegen.cc
    655 DEFINE_BOOL(always_inline_smi_code, false,
    656             "always inline smi code in non-opt code")
    657 DEFINE_BOOL(verify_operand_stack_depth, false,
    658             "emit debug code that verifies the static tracking of the operand "
    659             "stack depth")
    660 
    661 // heap.cc
    662 DEFINE_INT(min_semi_space_size, 0,
    663            "min size of a semi-space (in MBytes), the new space consists of two"
    664            "semi-spaces")
    665 DEFINE_INT(max_semi_space_size, 0,
    666            "max size of a semi-space (in MBytes), the new space consists of two"
    667            "semi-spaces")
    668 DEFINE_INT(semi_space_growth_factor, 2, "factor by which to grow the new space")
    669 DEFINE_BOOL(experimental_new_space_growth_heuristic, false,
    670             "Grow the new space based on the percentage of survivors instead "
    671             "of their absolute value.")
    672 DEFINE_INT(max_old_space_size, 0, "max size of the old space (in Mbytes)")
    673 DEFINE_INT(initial_old_space_size, 0, "initial old space size (in Mbytes)")
    674 DEFINE_INT(max_executable_size, 0, "max size of executable memory (in Mbytes)")
    675 DEFINE_BOOL(gc_global, false, "always perform global GCs")
    676 DEFINE_INT(gc_interval, -1, "garbage collect after <n> allocations")
    677 DEFINE_INT(retain_maps_for_n_gc, 2,
    678            "keeps maps alive for <n> old space garbage collections")
    679 DEFINE_BOOL(trace_gc, false,
    680             "print one trace line following each garbage collection")
    681 DEFINE_BOOL(trace_gc_nvp, false,
    682             "print one detailed trace line in name=value format "
    683             "after each garbage collection")
    684 DEFINE_BOOL(trace_gc_ignore_scavenger, false,
    685             "do not print trace line after scavenger collection")
    686 DEFINE_BOOL(trace_idle_notification, false,
    687             "print one trace line following each idle notification")
    688 DEFINE_BOOL(trace_idle_notification_verbose, false,
    689             "prints the heap state used by the idle notification")
    690 DEFINE_BOOL(print_cumulative_gc_stat, false,
    691             "print cumulative GC statistics in name=value format on exit")
    692 DEFINE_BOOL(print_max_heap_committed, false,
    693             "print statistics of the maximum memory committed for the heap "
    694             "in name=value format on exit")
    695 DEFINE_BOOL(trace_gc_verbose, false,
    696             "print more details following each garbage collection")
    697 DEFINE_INT(trace_allocation_stack_interval, -1,
    698            "print stack trace after <n> free-list allocations")
    699 DEFINE_BOOL(trace_fragmentation, false, "report fragmentation for old space")
    700 DEFINE_BOOL(trace_fragmentation_verbose, false,
    701             "report fragmentation for old space (detailed)")
    702 DEFINE_BOOL(trace_evacuation, false, "report evacuation statistics")
    703 DEFINE_BOOL(trace_mutator_utilization, false,
    704             "print mutator utilization, allocation speed, gc speed")
    705 DEFINE_BOOL(weak_embedded_maps_in_optimized_code, true,
    706             "make maps embedded in optimized code weak")
    707 DEFINE_BOOL(weak_embedded_objects_in_optimized_code, true,
    708             "make objects embedded in optimized code weak")
    709 DEFINE_BOOL(flush_code, true, "flush code that we expect not to use again")
    710 DEFINE_BOOL(trace_code_flushing, false, "trace code flushing progress")
    711 DEFINE_BOOL(age_code, true,
    712             "track un-executed functions to age code and flush only "
    713             "old code (required for code flushing)")
    714 DEFINE_BOOL(incremental_marking, true, "use incremental marking")
    715 DEFINE_INT(min_progress_during_incremental_marking_finalization, 32,
    716            "keep finalizing incremental marking as long as we discover at "
    717            "least this many unmarked objects")
    718 DEFINE_INT(max_incremental_marking_finalization_rounds, 3,
    719            "at most try this many times to finalize incremental marking")
    720 DEFINE_BOOL(black_allocation, false, "use black allocation")
    721 DEFINE_BOOL(concurrent_sweeping, true, "use concurrent sweeping")
    722 DEFINE_BOOL(parallel_compaction, true, "use parallel compaction")
    723 DEFINE_BOOL(parallel_pointer_update, true,
    724             "use parallel pointer update during compaction")
    725 DEFINE_BOOL(trace_incremental_marking, false,
    726             "trace progress of the incremental marking")
    727 DEFINE_BOOL(track_gc_object_stats, false,
    728             "track object counts and memory usage")
    729 DEFINE_BOOL(trace_gc_object_stats, false,
    730             "trace object counts and memory usage")
    731 DEFINE_IMPLICATION(trace_gc_object_stats, track_gc_object_stats)
    732 DEFINE_BOOL(track_detached_contexts, true,
    733             "track native contexts that are expected to be garbage collected")
    734 DEFINE_BOOL(trace_detached_contexts, false,
    735             "trace native contexts that are expected to be garbage collected")
    736 DEFINE_IMPLICATION(trace_detached_contexts, track_detached_contexts)
    737 #ifdef VERIFY_HEAP
    738 DEFINE_BOOL(verify_heap, false, "verify heap pointers before and after GC")
    739 #endif
    740 DEFINE_BOOL(move_object_start, true, "enable moving of object starts")
    741 DEFINE_BOOL(memory_reducer, true, "use memory reducer")
    742 DEFINE_BOOL(scavenge_reclaim_unmodified_objects, true,
    743             "remove unmodified and unreferenced objects")
    744 DEFINE_INT(heap_growing_percent, 0,
    745            "specifies heap growing factor as (1 + heap_growing_percent/100)")
    746 
    747 // counters.cc
    748 DEFINE_INT(histogram_interval, 600000,
    749            "time interval in ms for aggregating memory histograms")
    750 
    751 // global-handles.cc
    752 DEFINE_BOOL(trace_object_groups, false,
    753             "print object groups detected during each garbage collection")
    754 
    755 // heap-snapshot-generator.cc
    756 DEFINE_BOOL(heap_profiler_trace_objects, false,
    757             "Dump heap object allocations/movements/size_updates")
    758 
    759 
    760 // sampling-heap-profiler.cc
    761 DEFINE_BOOL(sampling_heap_profiler_suppress_randomness, false,
    762             "Use constant sample intervals to eliminate test flakiness")
    763 
    764 
    765 // v8.cc
    766 DEFINE_BOOL(use_idle_notification, true,
    767             "Use idle notification to reduce memory footprint.")
    768 // ic.cc
    769 DEFINE_BOOL(use_ic, true, "use inline caching")
    770 DEFINE_BOOL(trace_ic, false, "trace inline cache state transitions")
    771 DEFINE_BOOL(tf_load_ic_stub, true, "use TF LoadIC stub")
    772 
    773 // macro-assembler-ia32.cc
    774 DEFINE_BOOL(native_code_counters, false,
    775             "generate extra code for manipulating stats counters")
    776 
    777 // mark-compact.cc
    778 DEFINE_BOOL(always_compact, false, "Perform compaction on every full GC")
    779 DEFINE_BOOL(never_compact, false,
    780             "Never perform compaction on full GC - testing only")
    781 DEFINE_BOOL(compact_code_space, true, "Compact code space on full collections")
    782 DEFINE_BOOL(cleanup_code_caches_at_gc, true,
    783             "Flush inline caches prior to mark compact collection and "
    784             "flush code caches in maps during mark compact cycle.")
    785 DEFINE_BOOL(use_marking_progress_bar, true,
    786             "Use a progress bar to scan large objects in increments when "
    787             "incremental marking is active.")
    788 DEFINE_BOOL(zap_code_space, DEBUG_BOOL,
    789             "Zap free memory in code space with 0xCC while sweeping.")
    790 DEFINE_INT(random_seed, 0,
    791            "Default seed for initializing random generator "
    792            "(0, the default, means to use system random).")
    793 
    794 // objects.cc
    795 DEFINE_BOOL(trace_weak_arrays, false, "Trace WeakFixedArray usage")
    796 DEFINE_BOOL(trace_prototype_users, false,
    797             "Trace updates to prototype user tracking")
    798 DEFINE_BOOL(use_verbose_printer, true, "allows verbose printing")
    799 DEFINE_BOOL(trace_for_in_enumerate, false, "Trace for-in enumerate slow-paths")
    800 #if TRACE_MAPS
    801 DEFINE_BOOL(trace_maps, false, "trace map creation")
    802 #endif
    803 
    804 // parser.cc
    805 DEFINE_BOOL(allow_natives_syntax, false, "allow natives syntax")
    806 DEFINE_BOOL(trace_parse, false, "trace parsing and preparsing")
    807 
    808 // simulator-arm.cc, simulator-arm64.cc and simulator-mips.cc
    809 DEFINE_BOOL(trace_sim, false, "Trace simulator execution")
    810 DEFINE_BOOL(debug_sim, false, "Enable debugging the simulator")
    811 DEFINE_BOOL(check_icache, false,
    812             "Check icache flushes in ARM and MIPS simulator")
    813 DEFINE_INT(stop_sim_at, 0, "Simulator stop after x number of instructions")
    814 #if defined(V8_TARGET_ARCH_ARM64) || defined(V8_TARGET_ARCH_MIPS64) || \
    815     defined(V8_TARGET_ARCH_PPC64)
    816 DEFINE_INT(sim_stack_alignment, 16,
    817            "Stack alignment in bytes in simulator. This must be a power of two "
    818            "and it must be at least 16. 16 is default.")
    819 #else
    820 DEFINE_INT(sim_stack_alignment, 8,
    821            "Stack alingment in bytes in simulator (4 or 8, 8 is default)")
    822 #endif
    823 DEFINE_INT(sim_stack_size, 2 * MB / KB,
    824            "Stack size of the ARM64, MIPS64 and PPC64 simulator "
    825            "in kBytes (default is 2 MB)")
    826 DEFINE_BOOL(log_regs_modified, true,
    827             "When logging register values, only print modified registers.")
    828 DEFINE_BOOL(log_colour, ENABLE_LOG_COLOUR,
    829             "When logging, try to use coloured output.")
    830 DEFINE_BOOL(ignore_asm_unimplemented_break, false,
    831             "Don't break for ASM_UNIMPLEMENTED_BREAK macros.")
    832 DEFINE_BOOL(trace_sim_messages, false,
    833             "Trace simulator debug messages. Implied by --trace-sim.")
    834 
    835 // isolate.cc
    836 DEFINE_BOOL(stack_trace_on_illegal, false,
    837             "print stack trace when an illegal exception is thrown")
    838 DEFINE_BOOL(abort_on_uncaught_exception, false,
    839             "abort program (dump core) when an uncaught exception is thrown")
    840 DEFINE_BOOL(randomize_hashes, true,
    841             "randomize hashes to avoid predictable hash collisions "
    842             "(with snapshots this option cannot override the baked-in seed)")
    843 DEFINE_INT(hash_seed, 0,
    844            "Fixed seed to use to hash property keys (0 means random)"
    845            "(with snapshots this option cannot override the baked-in seed)")
    846 DEFINE_BOOL(trace_rail, false, "trace RAIL mode")
    847 
    848 // runtime.cc
    849 DEFINE_BOOL(runtime_call_stats, false, "report runtime call counts and times")
    850 
    851 // snapshot-common.cc
    852 DEFINE_BOOL(profile_deserialization, false,
    853             "Print the time it takes to deserialize the snapshot.")
    854 DEFINE_BOOL(serialization_statistics, false,
    855             "Collect statistics on serialized objects.")
    856 
    857 // Regexp
    858 DEFINE_BOOL(regexp_optimization, true, "generate optimized regexp code")
    859 
    860 // Testing flags test/cctest/test-{flags,api,serialization}.cc
    861 DEFINE_BOOL(testing_bool_flag, true, "testing_bool_flag")
    862 DEFINE_MAYBE_BOOL(testing_maybe_bool_flag, "testing_maybe_bool_flag")
    863 DEFINE_INT(testing_int_flag, 13, "testing_int_flag")
    864 DEFINE_FLOAT(testing_float_flag, 2.5, "float-flag")
    865 DEFINE_STRING(testing_string_flag, "Hello, world!", "string-flag")
    866 DEFINE_INT(testing_prng_seed, 42, "Seed used for threading test randomness")
    867 #ifdef _WIN32
    868 DEFINE_STRING(testing_serialization_file, "C:\\Windows\\Temp\\serdes",
    869               "file in which to testing_serialize heap")
    870 #else
    871 DEFINE_STRING(testing_serialization_file, "/tmp/serdes",
    872               "file in which to serialize heap")
    873 #endif
    874 
    875 // mksnapshot.cc
    876 DEFINE_STRING(startup_src, NULL,
    877               "Write V8 startup as C++ src. (mksnapshot only)")
    878 DEFINE_STRING(startup_blob, NULL,
    879               "Write V8 startup blob file. (mksnapshot only)")
    880 
    881 // code-stubs-hydrogen.cc
    882 DEFINE_BOOL(profile_hydrogen_code_stub_compilation, false,
    883             "Print the time it takes to lazily compile hydrogen code stubs.")
    884 
    885 DEFINE_BOOL(predictable, false, "enable predictable mode")
    886 DEFINE_NEG_IMPLICATION(predictable, concurrent_recompilation)
    887 DEFINE_NEG_IMPLICATION(predictable, concurrent_sweeping)
    888 DEFINE_NEG_IMPLICATION(predictable, parallel_compaction)
    889 DEFINE_NEG_IMPLICATION(predictable, memory_reducer)
    890 
    891 // mark-compact.cc
    892 DEFINE_BOOL(force_marking_deque_overflows, false,
    893             "force overflows of marking deque by reducing it's size "
    894             "to 64 words")
    895 
    896 DEFINE_BOOL(stress_compaction, false,
    897             "stress the GC compactor to flush out bugs (implies "
    898             "--force_marking_deque_overflows)")
    899 
    900 DEFINE_BOOL(manual_evacuation_candidates_selection, false,
    901             "Test mode only flag. It allows an unit test to select evacuation "
    902             "candidates pages (requires --stress_compaction).")
    903 
    904 // api.cc
    905 DEFINE_INT(external_allocation_limit_incremental_time, 1,
    906            "Time spent in incremental marking steps (in ms) once the external "
    907            "allocation limit is reached")
    908 
    909 DEFINE_BOOL(disable_old_api_accessors, false,
    910             "Disable old-style API accessors whose setters trigger through the "
    911             "prototype chain")
    912 
    913 //
    914 // Dev shell flags
    915 //
    916 
    917 DEFINE_BOOL(help, false, "Print usage message, including flags, on console")
    918 DEFINE_BOOL(dump_counters, false, "Dump counters on exit")
    919 
    920 DEFINE_STRING(map_counters, "", "Map counters to a file")
    921 DEFINE_ARGS(js_arguments,
    922             "Pass all remaining arguments to the script. Alias for \"--\".")
    923 
    924 //
    925 // GDB JIT integration flags.
    926 //
    927 #undef FLAG
    928 #ifdef ENABLE_GDB_JIT_INTERFACE
    929 #define FLAG FLAG_FULL
    930 #else
    931 #define FLAG FLAG_READONLY
    932 #endif
    933 
    934 DEFINE_BOOL(gdbjit, false, "enable GDBJIT interface")
    935 DEFINE_BOOL(gdbjit_full, false, "enable GDBJIT interface for all code objects")
    936 DEFINE_BOOL(gdbjit_dump, false, "dump elf objects with debug info to disk")
    937 DEFINE_STRING(gdbjit_dump_filter, "",
    938               "dump only objects containing this substring")
    939 
    940 #ifdef ENABLE_GDB_JIT_INTERFACE
    941 DEFINE_IMPLICATION(gdbjit_full, gdbjit)
    942 DEFINE_IMPLICATION(gdbjit_dump, gdbjit)
    943 #endif
    944 DEFINE_NEG_IMPLICATION(gdbjit, compact_code_space)
    945 
    946 //
    947 // Debug only flags
    948 //
    949 #undef FLAG
    950 #ifdef DEBUG
    951 #define FLAG FLAG_FULL
    952 #else
    953 #define FLAG FLAG_READONLY
    954 #endif
    955 
    956 // checks.cc
    957 #ifdef ENABLE_SLOW_DCHECKS
    958 DEFINE_BOOL(enable_slow_asserts, false,
    959             "enable asserts that are slow to execute")
    960 #endif
    961 
    962 // codegen-ia32.cc / codegen-arm.cc / macro-assembler-*.cc
    963 DEFINE_BOOL(print_source, false, "pretty print source code")
    964 DEFINE_BOOL(print_builtin_source, false,
    965             "pretty print source code for builtins")
    966 DEFINE_BOOL(print_ast, false, "print source AST")
    967 DEFINE_BOOL(print_builtin_ast, false, "print source AST for builtins")
    968 DEFINE_BOOL(trap_on_abort, false, "replace aborts by breakpoints")
    969 
    970 // compiler.cc
    971 DEFINE_BOOL(print_builtin_scopes, false, "print scopes for builtins")
    972 DEFINE_BOOL(print_scopes, false, "print scopes")
    973 
    974 // contexts.cc
    975 DEFINE_BOOL(trace_contexts, false, "trace contexts operations")
    976 
    977 // heap.cc
    978 DEFINE_BOOL(gc_verbose, false, "print stuff during garbage collection")
    979 DEFINE_BOOL(heap_stats, false, "report heap statistics before and after GC")
    980 DEFINE_BOOL(code_stats, false, "report code statistics after GC")
    981 DEFINE_BOOL(print_handles, false, "report handles after GC")
    982 DEFINE_BOOL(check_handle_count, false,
    983             "Check that there are not too many handles at GC")
    984 DEFINE_BOOL(print_global_handles, false, "report global handles after GC")
    985 
    986 // TurboFan debug-only flags.
    987 DEFINE_BOOL(print_turbo_replay, false,
    988             "print C++ code to recreate TurboFan graphs")
    989 DEFINE_BOOL(trace_turbo_escape, false, "enable tracing in escape analysis")
    990 
    991 // objects.cc
    992 DEFINE_BOOL(trace_normalization, false,
    993             "prints when objects are turned into dictionaries.")
    994 
    995 // runtime.cc
    996 DEFINE_BOOL(trace_lazy, false, "trace lazy compilation")
    997 
    998 // spaces.cc
    999 DEFINE_BOOL(collect_heap_spill_statistics, false,
   1000             "report heap spill statistics along with heap_stats "
   1001             "(requires heap_stats)")
   1002 DEFINE_BOOL(trace_live_bytes, false,
   1003             "trace incrementing and resetting of live bytes")
   1004 
   1005 DEFINE_BOOL(trace_isolates, false, "trace isolate state changes")
   1006 
   1007 // Regexp
   1008 DEFINE_BOOL(regexp_possessive_quantifier, false,
   1009             "enable possessive quantifier syntax for testing")
   1010 DEFINE_BOOL(trace_regexp_bytecodes, false, "trace regexp bytecode execution")
   1011 DEFINE_BOOL(trace_regexp_assembler, false,
   1012             "trace regexp macro assembler calls.")
   1013 DEFINE_BOOL(trace_regexp_parser, false, "trace regexp parsing")
   1014 
   1015 // Debugger
   1016 DEFINE_BOOL(print_break_location, false, "print source location on debug break")
   1017 
   1018 //
   1019 // Logging and profiling flags
   1020 //
   1021 #undef FLAG
   1022 #define FLAG FLAG_FULL
   1023 
   1024 // log.cc
   1025 DEFINE_BOOL(log, false,
   1026             "Minimal logging (no API, code, GC, suspect, or handles samples).")
   1027 DEFINE_BOOL(log_all, false, "Log all events to the log file.")
   1028 DEFINE_BOOL(log_api, false, "Log API events to the log file.")
   1029 DEFINE_BOOL(log_code, false,
   1030             "Log code events to the log file without profiling.")
   1031 DEFINE_BOOL(log_gc, false,
   1032             "Log heap samples on garbage collection for the hp2ps tool.")
   1033 DEFINE_BOOL(log_handles, false, "Log global handle events.")
   1034 DEFINE_BOOL(log_suspect, false, "Log suspect operations.")
   1035 DEFINE_BOOL(prof, false,
   1036             "Log statistical profiling information (implies --log-code).")
   1037 DEFINE_BOOL(prof_cpp, false, "Like --prof, but ignore generated code.")
   1038 DEFINE_IMPLICATION(prof, prof_cpp)
   1039 DEFINE_BOOL(prof_browser_mode, true,
   1040             "Used with --prof, turns on browser-compatible mode for profiling.")
   1041 DEFINE_BOOL(log_regexp, false, "Log regular expression execution.")
   1042 DEFINE_STRING(logfile, "v8.log", "Specify the name of the log file.")
   1043 DEFINE_BOOL(logfile_per_isolate, true, "Separate log files for each isolate.")
   1044 DEFINE_BOOL(ll_prof, false, "Enable low-level linux profiler.")
   1045 DEFINE_BOOL(perf_basic_prof, false,
   1046             "Enable perf linux profiler (basic support).")
   1047 DEFINE_NEG_IMPLICATION(perf_basic_prof, compact_code_space)
   1048 DEFINE_BOOL(perf_basic_prof_only_functions, false,
   1049             "Only report function code ranges to perf (i.e. no stubs).")
   1050 DEFINE_IMPLICATION(perf_basic_prof_only_functions, perf_basic_prof)
   1051 DEFINE_BOOL(perf_prof, false,
   1052             "Enable perf linux profiler (experimental annotate support).")
   1053 DEFINE_NEG_IMPLICATION(perf_prof, compact_code_space)
   1054 DEFINE_BOOL(perf_prof_debug_info, false,
   1055             "Enable debug info for perf linux profiler (experimental).")
   1056 DEFINE_BOOL(perf_prof_unwinding_info, false,
   1057             "Enable unwinding info for perf linux profiler (experimental).")
   1058 DEFINE_STRING(gc_fake_mmap, "/tmp/__v8_gc__",
   1059               "Specify the name of the file for fake gc mmap used in ll_prof")
   1060 DEFINE_BOOL(log_internal_timer_events, false, "Time internal events.")
   1061 DEFINE_BOOL(log_timer_events, false,
   1062             "Time events including external callbacks.")
   1063 DEFINE_IMPLICATION(log_timer_events, log_internal_timer_events)
   1064 DEFINE_IMPLICATION(log_internal_timer_events, prof)
   1065 DEFINE_BOOL(log_instruction_stats, false, "Log AArch64 instruction statistics.")
   1066 DEFINE_STRING(log_instruction_file, "arm64_inst.csv",
   1067               "AArch64 instruction statistics log file.")
   1068 DEFINE_INT(log_instruction_period, 1 << 22,
   1069            "AArch64 instruction statistics logging period.")
   1070 
   1071 DEFINE_BOOL(redirect_code_traces, false,
   1072             "output deopt information and disassembly into file "
   1073             "code-<pid>-<isolate id>.asm")
   1074 DEFINE_STRING(redirect_code_traces_to, NULL,
   1075               "output deopt information and disassembly into the given file")
   1076 
   1077 DEFINE_BOOL(hydrogen_track_positions, false,
   1078             "track source code positions when building IR")
   1079 
   1080 //
   1081 // Disassembler only flags
   1082 //
   1083 #undef FLAG
   1084 #ifdef ENABLE_DISASSEMBLER
   1085 #define FLAG FLAG_FULL
   1086 #else
   1087 #define FLAG FLAG_READONLY
   1088 #endif
   1089 
   1090 // elements.cc
   1091 DEFINE_BOOL(trace_elements_transitions, false, "trace elements transitions")
   1092 
   1093 DEFINE_BOOL(trace_creation_allocation_sites, false,
   1094             "trace the creation of allocation sites")
   1095 
   1096 // code-stubs.cc
   1097 DEFINE_BOOL(print_code_stubs, false, "print code stubs")
   1098 DEFINE_BOOL(test_secondary_stub_cache, false,
   1099             "test secondary stub cache by disabling the primary one")
   1100 
   1101 DEFINE_BOOL(test_primary_stub_cache, false,
   1102             "test primary stub cache by disabling the secondary one")
   1103 
   1104 
   1105 // codegen-ia32.cc / codegen-arm.cc
   1106 DEFINE_BOOL(print_code, false, "print generated code")
   1107 DEFINE_BOOL(print_opt_code, false, "print optimized code")
   1108 DEFINE_BOOL(print_unopt_code, false,
   1109             "print unoptimized code before "
   1110             "printing optimized code based on it")
   1111 DEFINE_BOOL(print_code_verbose, false, "print more information for code")
   1112 DEFINE_BOOL(print_builtin_code, false, "print generated code for builtins")
   1113 
   1114 #ifdef ENABLE_DISASSEMBLER
   1115 DEFINE_BOOL(sodium, false,
   1116             "print generated code output suitable for use with "
   1117             "the Sodium code viewer")
   1118 
   1119 DEFINE_IMPLICATION(sodium, print_code_stubs)
   1120 DEFINE_IMPLICATION(sodium, print_code)
   1121 DEFINE_IMPLICATION(sodium, print_opt_code)
   1122 DEFINE_IMPLICATION(sodium, hydrogen_track_positions)
   1123 DEFINE_IMPLICATION(sodium, code_comments)
   1124 
   1125 DEFINE_BOOL(print_all_code, false, "enable all flags related to printing code")
   1126 DEFINE_IMPLICATION(print_all_code, print_code)
   1127 DEFINE_IMPLICATION(print_all_code, print_opt_code)
   1128 DEFINE_IMPLICATION(print_all_code, print_unopt_code)
   1129 DEFINE_IMPLICATION(print_all_code, print_code_verbose)
   1130 DEFINE_IMPLICATION(print_all_code, print_builtin_code)
   1131 DEFINE_IMPLICATION(print_all_code, print_code_stubs)
   1132 DEFINE_IMPLICATION(print_all_code, code_comments)
   1133 #ifdef DEBUG
   1134 DEFINE_IMPLICATION(print_all_code, trace_codegen)
   1135 #endif
   1136 #endif
   1137 
   1138 
   1139 //
   1140 // VERIFY_PREDICTABLE related flags
   1141 //
   1142 #undef FLAG
   1143 
   1144 #ifdef VERIFY_PREDICTABLE
   1145 #define FLAG FLAG_FULL
   1146 #else
   1147 #define FLAG FLAG_READONLY
   1148 #endif
   1149 
   1150 DEFINE_BOOL(verify_predictable, false,
   1151             "this mode is used for checking that V8 behaves predictably")
   1152 DEFINE_INT(dump_allocations_digest_at_alloc, -1,
   1153            "dump allocations digest each n-th allocation")
   1154 
   1155 
   1156 //
   1157 // Read-only flags
   1158 //
   1159 #undef FLAG
   1160 #define FLAG FLAG_READONLY
   1161 
   1162 // assembler.h
   1163 DEFINE_BOOL(enable_embedded_constant_pool, V8_EMBEDDED_CONSTANT_POOL,
   1164             "enable use of embedded constant pools (ARM/PPC only)")
   1165 
   1166 DEFINE_BOOL(unbox_double_fields, V8_DOUBLE_FIELDS_UNBOXING,
   1167             "enable in-object double fields unboxing (64-bit only)")
   1168 DEFINE_IMPLICATION(unbox_double_fields, track_double_fields)
   1169 
   1170 DEFINE_BOOL(global_var_shortcuts, false, "use ic-less global loads and stores")
   1171 
   1172 
   1173 // Cleanup...
   1174 #undef FLAG_FULL
   1175 #undef FLAG_READONLY
   1176 #undef FLAG
   1177 #undef FLAG_ALIAS
   1178 
   1179 #undef DEFINE_BOOL
   1180 #undef DEFINE_MAYBE_BOOL
   1181 #undef DEFINE_INT
   1182 #undef DEFINE_STRING
   1183 #undef DEFINE_FLOAT
   1184 #undef DEFINE_ARGS
   1185 #undef DEFINE_IMPLICATION
   1186 #undef DEFINE_NEG_IMPLICATION
   1187 #undef DEFINE_NEG_VALUE_IMPLICATION
   1188 #undef DEFINE_VALUE_IMPLICATION
   1189 #undef DEFINE_ALIAS_BOOL
   1190 #undef DEFINE_ALIAS_INT
   1191 #undef DEFINE_ALIAS_STRING
   1192 #undef DEFINE_ALIAS_FLOAT
   1193 #undef DEFINE_ALIAS_ARGS
   1194 
   1195 #undef FLAG_MODE_DECLARE
   1196 #undef FLAG_MODE_DEFINE
   1197 #undef FLAG_MODE_DEFINE_DEFAULTS
   1198 #undef FLAG_MODE_META
   1199 #undef FLAG_MODE_DEFINE_IMPLICATIONS
   1200 
   1201 #undef COMMA
   1202