1 // Copyright 2006-2008 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 #include "src/flags/flags.h"
6
7 #include <cctype>
8 #include <cerrno>
9 #include <cinttypes>
10 #include <cstdlib>
11 #include <cstring>
12 #include <iomanip>
13 #include <sstream>
14
15 #include "src/base/functional.h"
16 #include "src/base/logging.h"
17 #include "src/base/platform/platform.h"
18 #include "src/codegen/cpu-features.h"
19 #include "src/logging/counters.h"
20 #include "src/logging/tracing-flags.h"
21 #include "src/tracing/tracing-category-observer.h"
22 #include "src/utils/allocation.h"
23 #include "src/utils/memcopy.h"
24 #include "src/utils/ostreams.h"
25 #include "src/utils/utils.h"
26
27 #if V8_ENABLE_WEBASSEMBLY
28 #include "src/wasm/wasm-limits.h"
29 #endif // V8_ENABLE_WEBASSEMBLY
30
31 namespace v8 {
32 namespace internal {
33
34 // Define all of our flags.
35 #define FLAG_MODE_DEFINE
36 #include "src/flags/flag-definitions.h" // NOLINT(build/include)
37
38 // Define all of our flags default values.
39 #define FLAG_MODE_DEFINE_DEFAULTS
40 #include "src/flags/flag-definitions.h" // NOLINT(build/include)
41
42 namespace {
43
NormalizeChar(char ch)44 char NormalizeChar(char ch) { return ch == '_' ? '-' : ch; }
45
46 struct Flag;
47 Flag* FindFlagByPointer(const void* ptr);
48 Flag* FindFlagByName(const char* name);
49
50 // This structure represents a single entry in the flag system, with a pointer
51 // to the actual flag, default value, comment, etc. This is designed to be POD
52 // initialized as to avoid requiring static constructors.
53 struct Flag {
54 enum FlagType {
55 TYPE_BOOL,
56 TYPE_MAYBE_BOOL,
57 TYPE_INT,
58 TYPE_UINT,
59 TYPE_UINT64,
60 TYPE_FLOAT,
61 TYPE_SIZE_T,
62 TYPE_STRING,
63 };
64
65 enum class SetBy { kDefault, kWeakImplication, kImplication, kCommandLine };
66
67 FlagType type_; // What type of flag, bool, int, or string.
68 const char* name_; // Name of the flag, ex "my_flag".
69 void* valptr_; // Pointer to the global flag variable.
70 const void* defptr_; // Pointer to the default value.
71 const char* cmt_; // A comment about the flags purpose.
72 bool owns_ptr_; // Does the flag own its string value?
73 SetBy set_by_ = SetBy::kDefault;
74 const char* implied_by_ = nullptr;
75
typev8::internal::__anon4507bcf00111::Flag76 FlagType type() const { return type_; }
77
namev8::internal::__anon4507bcf00111::Flag78 const char* name() const { return name_; }
79
commentv8::internal::__anon4507bcf00111::Flag80 const char* comment() const { return cmt_; }
81
PointsTov8::internal::__anon4507bcf00111::Flag82 bool PointsTo(const void* ptr) const { return valptr_ == ptr; }
83
bool_variablev8::internal::__anon4507bcf00111::Flag84 bool bool_variable() const {
85 DCHECK(type_ == TYPE_BOOL);
86 return *reinterpret_cast<bool*>(valptr_);
87 }
88
set_bool_variablev8::internal::__anon4507bcf00111::Flag89 void set_bool_variable(bool value, SetBy set_by) {
90 DCHECK(type_ == TYPE_BOOL);
91 bool change_flag = *reinterpret_cast<bool*>(valptr_) != value;
92 change_flag = CheckFlagChange(set_by, change_flag);
93 if (change_flag) *reinterpret_cast<bool*>(valptr_) = value;
94 }
95
maybe_bool_variablev8::internal::__anon4507bcf00111::Flag96 MaybeBoolFlag maybe_bool_variable() const {
97 DCHECK(type_ == TYPE_MAYBE_BOOL);
98 return *reinterpret_cast<MaybeBoolFlag*>(valptr_);
99 }
100
set_maybe_bool_variablev8::internal::__anon4507bcf00111::Flag101 void set_maybe_bool_variable(MaybeBoolFlag value, SetBy set_by) {
102 DCHECK(type_ == TYPE_MAYBE_BOOL);
103 bool change_flag = *reinterpret_cast<MaybeBoolFlag*>(valptr_) != value;
104 change_flag = CheckFlagChange(set_by, change_flag);
105 if (change_flag) *reinterpret_cast<MaybeBoolFlag*>(valptr_) = value;
106 }
107
int_variablev8::internal::__anon4507bcf00111::Flag108 int int_variable() const {
109 DCHECK(type_ == TYPE_INT);
110 return *reinterpret_cast<int*>(valptr_);
111 }
112
set_int_variablev8::internal::__anon4507bcf00111::Flag113 void set_int_variable(int value, SetBy set_by) {
114 DCHECK(type_ == TYPE_INT);
115 bool change_flag = *reinterpret_cast<int*>(valptr_) != value;
116 change_flag = CheckFlagChange(set_by, change_flag);
117 if (change_flag) *reinterpret_cast<int*>(valptr_) = value;
118 }
119
uint_variablev8::internal::__anon4507bcf00111::Flag120 unsigned int uint_variable() const {
121 DCHECK(type_ == TYPE_UINT);
122 return *reinterpret_cast<unsigned int*>(valptr_);
123 }
124
set_uint_variablev8::internal::__anon4507bcf00111::Flag125 void set_uint_variable(unsigned int value, SetBy set_by) {
126 DCHECK(type_ == TYPE_UINT);
127 bool change_flag = *reinterpret_cast<unsigned int*>(valptr_) != value;
128 change_flag = CheckFlagChange(set_by, change_flag);
129 if (change_flag) *reinterpret_cast<unsigned int*>(valptr_) = value;
130 }
131
uint64_variablev8::internal::__anon4507bcf00111::Flag132 uint64_t uint64_variable() const {
133 DCHECK(type_ == TYPE_UINT64);
134 return *reinterpret_cast<uint64_t*>(valptr_);
135 }
136
set_uint64_variablev8::internal::__anon4507bcf00111::Flag137 void set_uint64_variable(uint64_t value, SetBy set_by) {
138 DCHECK(type_ == TYPE_UINT64);
139 bool change_flag = *reinterpret_cast<uint64_t*>(valptr_) != value;
140 change_flag = CheckFlagChange(set_by, change_flag);
141 if (change_flag) *reinterpret_cast<uint64_t*>(valptr_) = value;
142 }
143
float_variablev8::internal::__anon4507bcf00111::Flag144 double float_variable() const {
145 DCHECK(type_ == TYPE_FLOAT);
146 return *reinterpret_cast<double*>(valptr_);
147 }
148
set_float_variablev8::internal::__anon4507bcf00111::Flag149 void set_float_variable(double value, SetBy set_by) {
150 DCHECK(type_ == TYPE_FLOAT);
151 bool change_flag = *reinterpret_cast<double*>(valptr_) != value;
152 change_flag = CheckFlagChange(set_by, change_flag);
153 if (change_flag) *reinterpret_cast<double*>(valptr_) = value;
154 }
155
size_t_variablev8::internal::__anon4507bcf00111::Flag156 size_t size_t_variable() const {
157 DCHECK(type_ == TYPE_SIZE_T);
158 return *reinterpret_cast<size_t*>(valptr_);
159 }
160
set_size_t_variablev8::internal::__anon4507bcf00111::Flag161 void set_size_t_variable(size_t value, SetBy set_by) {
162 DCHECK(type_ == TYPE_SIZE_T);
163 bool change_flag = *reinterpret_cast<size_t*>(valptr_) != value;
164 change_flag = CheckFlagChange(set_by, change_flag);
165 if (change_flag) *reinterpret_cast<size_t*>(valptr_) = value;
166 }
167
string_valuev8::internal::__anon4507bcf00111::Flag168 const char* string_value() const {
169 DCHECK(type_ == TYPE_STRING);
170 return *reinterpret_cast<const char**>(valptr_);
171 }
172
set_string_valuev8::internal::__anon4507bcf00111::Flag173 void set_string_value(const char* value, bool owns_ptr, SetBy set_by) {
174 DCHECK(type_ == TYPE_STRING);
175 const char** ptr = reinterpret_cast<const char**>(valptr_);
176 bool change_flag = (*ptr == nullptr) != (value == nullptr) ||
177 (*ptr && value && std::strcmp(*ptr, value) != 0);
178 change_flag = CheckFlagChange(set_by, change_flag);
179 if (change_flag) {
180 if (owns_ptr_ && *ptr != nullptr) DeleteArray(*ptr);
181 *ptr = value;
182 owns_ptr_ = owns_ptr;
183 } else {
184 if (owns_ptr && value != nullptr) DeleteArray(value);
185 }
186 }
187
bool_defaultv8::internal::__anon4507bcf00111::Flag188 bool bool_default() const {
189 DCHECK(type_ == TYPE_BOOL);
190 return *reinterpret_cast<const bool*>(defptr_);
191 }
192
int_defaultv8::internal::__anon4507bcf00111::Flag193 int int_default() const {
194 DCHECK(type_ == TYPE_INT);
195 return *reinterpret_cast<const int*>(defptr_);
196 }
197
uint_defaultv8::internal::__anon4507bcf00111::Flag198 unsigned int uint_default() const {
199 DCHECK(type_ == TYPE_UINT);
200 return *reinterpret_cast<const unsigned int*>(defptr_);
201 }
202
uint64_defaultv8::internal::__anon4507bcf00111::Flag203 uint64_t uint64_default() const {
204 DCHECK(type_ == TYPE_UINT64);
205 return *reinterpret_cast<const uint64_t*>(defptr_);
206 }
207
float_defaultv8::internal::__anon4507bcf00111::Flag208 double float_default() const {
209 DCHECK(type_ == TYPE_FLOAT);
210 return *reinterpret_cast<const double*>(defptr_);
211 }
212
size_t_defaultv8::internal::__anon4507bcf00111::Flag213 size_t size_t_default() const {
214 DCHECK(type_ == TYPE_SIZE_T);
215 return *reinterpret_cast<const size_t*>(defptr_);
216 }
217
string_defaultv8::internal::__anon4507bcf00111::Flag218 const char* string_default() const {
219 DCHECK(type_ == TYPE_STRING);
220 return *reinterpret_cast<const char* const*>(defptr_);
221 }
222
ShouldCheckFlagContradictionsv8::internal::__anon4507bcf00111::Flag223 static bool ShouldCheckFlagContradictions() {
224 if (FLAG_allow_overwriting_for_next_flag) {
225 // Setting the flag manually to false before calling Reset() avoids this
226 // becoming re-entrant.
227 FLAG_allow_overwriting_for_next_flag = false;
228 FindFlagByPointer(&FLAG_allow_overwriting_for_next_flag)->Reset();
229 return false;
230 }
231 return FLAG_abort_on_contradictory_flags && !FLAG_fuzzing;
232 }
233
234 // {change_flag} indicates if we're going to change the flag value.
235 // Returns an updated value for {change_flag}, which is changed to false if a
236 // weak implication is being ignored beause a flag is already set by a normal
237 // implication or from the command-line.
CheckFlagChangev8::internal::__anon4507bcf00111::Flag238 bool CheckFlagChange(SetBy new_set_by, bool change_flag,
239 const char* implied_by = nullptr) {
240 if (new_set_by == SetBy::kWeakImplication &&
241 (set_by_ == SetBy::kImplication || set_by_ == SetBy::kCommandLine)) {
242 return false;
243 }
244 if (ShouldCheckFlagContradictions()) {
245 // For bool flags, we only check for a conflict if the value actually
246 // changes. So specifying the same flag with the same value multiple times
247 // is allowed.
248 // For other flags, we disallow specifying them explicitly or in the
249 // presence of an implication even if the value is the same.
250 // This is to simplify the rules describing conflicts in variants.py: A
251 // repeated non-boolean flag is considered an error independently of its
252 // value.
253 bool is_bool_flag = type_ == TYPE_MAYBE_BOOL || type_ == TYPE_BOOL;
254 bool check_implications = change_flag;
255 bool check_command_line_flags = change_flag || !is_bool_flag;
256 const char* hint =
257 "To fix this, it might be necessary to specify additional "
258 "contradictory flags in tools/testrunner/local/variants.py.";
259 switch (set_by_) {
260 case SetBy::kDefault:
261 break;
262 case SetBy::kWeakImplication:
263 if (new_set_by == SetBy::kWeakImplication && check_implications) {
264 FATAL(
265 "Contradictory weak flag implications from --%s and --%s for "
266 "flag %s\n%s",
267 implied_by_, implied_by, name(), hint);
268 }
269 break;
270 case SetBy::kImplication:
271 if (new_set_by == SetBy::kImplication && check_implications) {
272 FATAL(
273 "Contradictory flag implications from --%s and --%s for flag "
274 "%s\n%s",
275 implied_by_, implied_by, name(), hint);
276 }
277 break;
278 case SetBy::kCommandLine:
279 if (new_set_by == SetBy::kImplication && check_command_line_flags) {
280 if (is_bool_flag) {
281 FATAL(
282 "Flag --%s: value implied by --%s conflicts with explicit "
283 "specification\n%s",
284 name(), implied_by, hint);
285 } else {
286 FATAL(
287 "Flag --%s is implied by --%s but also specified "
288 "explicitly.\n%s",
289 name(), implied_by, hint);
290 }
291 } else if (new_set_by == SetBy::kCommandLine &&
292 check_command_line_flags) {
293 if (is_bool_flag) {
294 FATAL(
295 "Command-line provided flag --%s specified as both true and "
296 "false.\n%s",
297 name(), hint);
298 } else {
299 FATAL(
300 "Command-line provided flag --%s specified multiple "
301 "times.\n%s",
302 name(), hint);
303 }
304 }
305 break;
306 }
307 }
308 set_by_ = new_set_by;
309 if (new_set_by == SetBy::kImplication ||
310 new_set_by == SetBy::kWeakImplication) {
311 DCHECK_NOT_NULL(implied_by);
312 implied_by_ = implied_by;
313 }
314 return change_flag;
315 }
316
317 // Compare this flag's current value against the default.
IsDefaultv8::internal::__anon4507bcf00111::Flag318 bool IsDefault() const {
319 switch (type_) {
320 case TYPE_BOOL:
321 return bool_variable() == bool_default();
322 case TYPE_MAYBE_BOOL:
323 return maybe_bool_variable().has_value == false;
324 case TYPE_INT:
325 return int_variable() == int_default();
326 case TYPE_UINT:
327 return uint_variable() == uint_default();
328 case TYPE_UINT64:
329 return uint64_variable() == uint64_default();
330 case TYPE_FLOAT:
331 return float_variable() == float_default();
332 case TYPE_SIZE_T:
333 return size_t_variable() == size_t_default();
334 case TYPE_STRING: {
335 const char* str1 = string_value();
336 const char* str2 = string_default();
337 if (str2 == nullptr) return str1 == nullptr;
338 if (str1 == nullptr) return str2 == nullptr;
339 return strcmp(str1, str2) == 0;
340 }
341 }
342 UNREACHABLE();
343 }
344
345 // Set a flag back to it's default value.
Resetv8::internal::__anon4507bcf00111::Flag346 void Reset() {
347 switch (type_) {
348 case TYPE_BOOL:
349 set_bool_variable(bool_default(), SetBy::kDefault);
350 break;
351 case TYPE_MAYBE_BOOL:
352 set_maybe_bool_variable(MaybeBoolFlag::Create(false, false),
353 SetBy::kDefault);
354 break;
355 case TYPE_INT:
356 set_int_variable(int_default(), SetBy::kDefault);
357 break;
358 case TYPE_UINT:
359 set_uint_variable(uint_default(), SetBy::kDefault);
360 break;
361 case TYPE_UINT64:
362 set_uint64_variable(uint64_default(), SetBy::kDefault);
363 break;
364 case TYPE_FLOAT:
365 set_float_variable(float_default(), SetBy::kDefault);
366 break;
367 case TYPE_SIZE_T:
368 set_size_t_variable(size_t_default(), SetBy::kDefault);
369 break;
370 case TYPE_STRING:
371 set_string_value(string_default(), false, SetBy::kDefault);
372 break;
373 }
374 }
375
AllowOverwritingv8::internal::__anon4507bcf00111::Flag376 void AllowOverwriting() { set_by_ = SetBy::kDefault; }
377 };
378
379 Flag flags[] = {
380 #define FLAG_MODE_META
381 #include "src/flags/flag-definitions.h" // NOLINT(build/include)
382 };
383
384 const size_t num_flags = sizeof(flags) / sizeof(*flags);
385
EqualNames(const char * a,const char * b)386 bool EqualNames(const char* a, const char* b) {
387 for (int i = 0; NormalizeChar(a[i]) == NormalizeChar(b[i]); i++) {
388 if (a[i] == '\0') {
389 return true;
390 }
391 }
392 return false;
393 }
394
FindFlagByName(const char * name)395 Flag* FindFlagByName(const char* name) {
396 for (size_t i = 0; i < num_flags; ++i) {
397 if (EqualNames(name, flags[i].name())) return &flags[i];
398 }
399 return nullptr;
400 }
401
FindFlagByPointer(const void * ptr)402 Flag* FindFlagByPointer(const void* ptr) {
403 for (size_t i = 0; i < num_flags; ++i) {
404 if (flags[i].PointsTo(ptr)) return &flags[i];
405 }
406 return nullptr;
407 }
408
409 } // namespace
410
Type2String(Flag::FlagType type)411 static const char* Type2String(Flag::FlagType type) {
412 switch (type) {
413 case Flag::TYPE_BOOL:
414 return "bool";
415 case Flag::TYPE_MAYBE_BOOL:
416 return "maybe_bool";
417 case Flag::TYPE_INT:
418 return "int";
419 case Flag::TYPE_UINT:
420 return "uint";
421 case Flag::TYPE_UINT64:
422 return "uint64";
423 case Flag::TYPE_FLOAT:
424 return "float";
425 case Flag::TYPE_SIZE_T:
426 return "size_t";
427 case Flag::TYPE_STRING:
428 return "string";
429 }
430 UNREACHABLE();
431 }
432
433 // Helper struct for printing normalize Flag names.
434 struct FlagName {
FlagNamev8::internal::FlagName435 explicit FlagName(const Flag& flag) : flag(flag) {}
436 const Flag& flag;
437 };
438
operator <<(std::ostream & os,const FlagName & flag_name)439 std::ostream& operator<<(std::ostream& os, const FlagName& flag_name) {
440 for (const char* c = flag_name.flag.name(); *c != '\0'; ++c) {
441 os << NormalizeChar(*c);
442 }
443 return os;
444 }
445
446 // Helper for printing flag values.
447 struct FlagValue {
FlagValuev8::internal::FlagValue448 explicit FlagValue(const Flag& flag) : flag(flag) {}
449 const Flag& flag;
450 };
451
operator <<(std::ostream & os,const FlagValue & flag_value)452 std::ostream& operator<<(std::ostream& os, const FlagValue& flag_value) {
453 const Flag& flag = flag_value.flag;
454 switch (flag.type()) {
455 case Flag::TYPE_BOOL:
456 os << (flag.bool_variable() ? "true" : "false");
457 break;
458 case Flag::TYPE_MAYBE_BOOL:
459 os << (flag.maybe_bool_variable().has_value
460 ? (flag.maybe_bool_variable().value ? "true" : "false")
461 : "unset");
462 break;
463 case Flag::TYPE_INT:
464 os << flag.int_variable();
465 break;
466 case Flag::TYPE_UINT:
467 os << flag.uint_variable();
468 break;
469 case Flag::TYPE_UINT64:
470 os << flag.uint64_variable();
471 break;
472 case Flag::TYPE_FLOAT:
473 os << flag.float_variable();
474 break;
475 case Flag::TYPE_SIZE_T:
476 os << flag.size_t_variable();
477 break;
478 case Flag::TYPE_STRING: {
479 const char* str = flag.string_value();
480 os << std::quoted(str ? str : "");
481 break;
482 }
483 }
484 return os;
485 }
486
operator <<(std::ostream & os,const Flag & flag)487 std::ostream& operator<<(std::ostream& os, const Flag& flag) {
488 if (flag.type() == Flag::TYPE_BOOL) {
489 os << (flag.bool_variable() ? "--" : "--no") << FlagName(flag);
490 } else {
491 os << "--" << FlagName(flag) << "=" << FlagValue(flag);
492 }
493 return os;
494 }
495
496 namespace {
497
498 static std::atomic<uint32_t> flag_hash(0);
499
ComputeFlagListHash()500 void ComputeFlagListHash() {
501 std::ostringstream modified_args_as_string;
502 if (COMPRESS_POINTERS_BOOL) modified_args_as_string << "ptr-compr";
503 if (DEBUG_BOOL) modified_args_as_string << "debug";
504 for (const Flag& flag : flags) {
505 if (flag.IsDefault()) continue;
506 // We want to be able to flip --profile-deserialization without
507 // causing the code cache to get invalidated by this hash.
508 if (flag.PointsTo(&FLAG_profile_deserialization)) continue;
509 // Skip FLAG_random_seed to allow predictable code caching.
510 if (flag.PointsTo(&FLAG_random_seed)) continue;
511 modified_args_as_string << flag;
512 }
513 std::string args(modified_args_as_string.str());
514 // Generate a hash that is not 0.
515 uint32_t hash = static_cast<uint32_t>(base::hash_range(
516 args.c_str(), args.c_str() + args.length())) |
517 1;
518 DCHECK_NE(hash, 0);
519 flag_hash.store(hash, std::memory_order_relaxed);
520 }
521
522 } // namespace
523
524 // Helper function to parse flags: Takes an argument arg and splits it into
525 // a flag name and flag value (or nullptr if they are missing). negated is set
526 // if the arg started with "-no" or "--no". The buffer may be used to NUL-
527 // terminate the name, it must be large enough to hold any possible name.
SplitArgument(const char * arg,char * buffer,int buffer_size,const char ** name,const char ** value,bool * negated)528 static void SplitArgument(const char* arg, char* buffer, int buffer_size,
529 const char** name, const char** value,
530 bool* negated) {
531 *name = nullptr;
532 *value = nullptr;
533 *negated = false;
534
535 if (arg != nullptr && *arg == '-') {
536 // find the begin of the flag name
537 arg++; // remove 1st '-'
538 if (*arg == '-') {
539 arg++; // remove 2nd '-'
540 DCHECK_NE('\0', arg[0]); // '--' arguments are handled in the caller.
541 }
542 if (arg[0] == 'n' && arg[1] == 'o') {
543 arg += 2; // remove "no"
544 if (NormalizeChar(arg[0]) == '-') arg++; // remove dash after "no".
545 *negated = true;
546 }
547 *name = arg;
548
549 // find the end of the flag name
550 while (*arg != '\0' && *arg != '=') arg++;
551
552 // get the value if any
553 if (*arg == '=') {
554 // make a copy so we can NUL-terminate flag name
555 size_t n = arg - *name;
556 CHECK(n < static_cast<size_t>(buffer_size)); // buffer is too small
557 MemCopy(buffer, *name, n);
558 buffer[n] = '\0';
559 *name = buffer;
560 // get the value
561 *value = arg + 1;
562 }
563 }
564 }
565
566 template <typename T>
TryParseUnsigned(Flag * flag,const char * arg,const char * value,char ** endp,T * out_val)567 bool TryParseUnsigned(Flag* flag, const char* arg, const char* value,
568 char** endp, T* out_val) {
569 // We do not use strtoul because it accepts negative numbers.
570 // Rejects values >= 2**63 when T is 64 bits wide but that
571 // seems like an acceptable trade-off.
572 uint64_t max = static_cast<uint64_t>(std::numeric_limits<T>::max());
573 errno = 0;
574 int64_t val = static_cast<int64_t>(strtoll(value, endp, 10));
575 if (val < 0 || static_cast<uint64_t>(val) > max || errno != 0) {
576 PrintF(stderr,
577 "Error: Value for flag %s of type %s is out of bounds "
578 "[0-%" PRIu64 "]\n",
579 arg, Type2String(flag->type()), max);
580 return false;
581 }
582 *out_val = static_cast<T>(val);
583 return true;
584 }
585
586 // static
SetFlagsFromCommandLine(int * argc,char ** argv,bool remove_flags,HelpOptions help_options)587 int FlagList::SetFlagsFromCommandLine(int* argc, char** argv, bool remove_flags,
588 HelpOptions help_options) {
589 int return_code = 0;
590 // parse arguments
591 for (int i = 1; i < *argc;) {
592 int j = i; // j > 0
593 const char* arg = argv[i++];
594
595 // split arg into flag components
596 char buffer[1 * KB];
597 const char* name;
598 const char* value;
599 bool negated;
600 SplitArgument(arg, buffer, sizeof buffer, &name, &value, &negated);
601
602 if (name != nullptr) {
603 // lookup the flag
604 Flag* flag = FindFlagByName(name);
605 if (flag == nullptr) {
606 if (remove_flags) {
607 // We don't recognize this flag but since we're removing
608 // the flags we recognize we assume that the remaining flags
609 // will be processed somewhere else so this flag might make
610 // sense there.
611 continue;
612 } else {
613 PrintF(stderr, "Error: unrecognized flag %s\n", arg);
614 return_code = j;
615 break;
616 }
617 }
618
619 // if we still need a flag value, use the next argument if available
620 if (flag->type() != Flag::TYPE_BOOL &&
621 flag->type() != Flag::TYPE_MAYBE_BOOL && value == nullptr) {
622 if (i < *argc) {
623 value = argv[i++];
624 }
625 if (!value) {
626 PrintF(stderr, "Error: missing value for flag %s of type %s\n", arg,
627 Type2String(flag->type()));
628 return_code = j;
629 break;
630 }
631 }
632
633 // set the flag
634 char* endp = const_cast<char*>(""); // *endp is only read
635 switch (flag->type()) {
636 case Flag::TYPE_BOOL:
637 flag->set_bool_variable(!negated, Flag::SetBy::kCommandLine);
638 break;
639 case Flag::TYPE_MAYBE_BOOL:
640 flag->set_maybe_bool_variable(MaybeBoolFlag::Create(true, !negated),
641 Flag::SetBy::kCommandLine);
642 break;
643 case Flag::TYPE_INT:
644 flag->set_int_variable(static_cast<int>(strtol(value, &endp, 10)),
645 Flag::SetBy::kCommandLine);
646 break;
647 case Flag::TYPE_UINT: {
648 unsigned int parsed_value;
649 if (TryParseUnsigned(flag, arg, value, &endp, &parsed_value)) {
650 flag->set_uint_variable(parsed_value, Flag::SetBy::kCommandLine);
651 } else {
652 return_code = j;
653 }
654 break;
655 }
656 case Flag::TYPE_UINT64: {
657 uint64_t parsed_value;
658 if (TryParseUnsigned(flag, arg, value, &endp, &parsed_value)) {
659 flag->set_uint64_variable(parsed_value, Flag::SetBy::kCommandLine);
660 } else {
661 return_code = j;
662 }
663 break;
664 }
665 case Flag::TYPE_FLOAT:
666 flag->set_float_variable(strtod(value, &endp),
667 Flag::SetBy::kCommandLine);
668 break;
669 case Flag::TYPE_SIZE_T: {
670 size_t parsed_value;
671 if (TryParseUnsigned(flag, arg, value, &endp, &parsed_value)) {
672 flag->set_size_t_variable(parsed_value, Flag::SetBy::kCommandLine);
673 } else {
674 return_code = j;
675 }
676 break;
677 }
678 case Flag::TYPE_STRING:
679 flag->set_string_value(value ? StrDup(value) : nullptr, true,
680 Flag::SetBy::kCommandLine);
681 break;
682 }
683
684 // handle errors
685 bool is_bool_type = flag->type() == Flag::TYPE_BOOL ||
686 flag->type() == Flag::TYPE_MAYBE_BOOL;
687 if ((is_bool_type && value != nullptr) || (!is_bool_type && negated) ||
688 *endp != '\0') {
689 // TODO(neis): TryParseUnsigned may return with {*endp == '\0'} even in
690 // an error case.
691 PrintF(stderr, "Error: illegal value for flag %s of type %s\n", arg,
692 Type2String(flag->type()));
693 if (is_bool_type) {
694 PrintF(stderr,
695 "To set or unset a boolean flag, use --flag or --no-flag.\n");
696 }
697 return_code = j;
698 break;
699 }
700
701 // remove the flag & value from the command
702 if (remove_flags) {
703 while (j < i) {
704 argv[j++] = nullptr;
705 }
706 }
707 }
708 }
709
710 if (FLAG_help) {
711 if (help_options.HasUsage()) {
712 PrintF(stdout, "%s", help_options.usage());
713 }
714 PrintHelp();
715 if (help_options.ShouldExit()) {
716 exit(0);
717 }
718 }
719
720 if (remove_flags) {
721 // shrink the argument list
722 int j = 1;
723 for (int i = 1; i < *argc; i++) {
724 if (argv[i] != nullptr) argv[j++] = argv[i];
725 }
726 *argc = j;
727 } else if (return_code != 0) {
728 if (return_code + 1 < *argc) {
729 PrintF(stderr, "The remaining arguments were ignored:");
730 for (int i = return_code + 1; i < *argc; ++i) {
731 PrintF(stderr, " %s", argv[i]);
732 }
733 PrintF(stderr, "\n");
734 }
735 }
736 if (return_code != 0) PrintF(stderr, "Try --help for options\n");
737
738 return return_code;
739 }
740
SkipWhiteSpace(char * p)741 static char* SkipWhiteSpace(char* p) {
742 while (*p != '\0' && isspace(*p) != 0) p++;
743 return p;
744 }
745
SkipBlackSpace(char * p)746 static char* SkipBlackSpace(char* p) {
747 while (*p != '\0' && isspace(*p) == 0) p++;
748 return p;
749 }
750
751 // static
SetFlagsFromString(const char * str,size_t len)752 int FlagList::SetFlagsFromString(const char* str, size_t len) {
753 // make a 0-terminated copy of str
754 std::unique_ptr<char[]> copy0{NewArray<char>(len + 1)};
755 MemCopy(copy0.get(), str, len);
756 copy0[len] = '\0';
757
758 // strip leading white space
759 char* copy = SkipWhiteSpace(copy0.get());
760
761 // count the number of 'arguments'
762 int argc = 1; // be compatible with SetFlagsFromCommandLine()
763 for (char* p = copy; *p != '\0'; argc++) {
764 p = SkipBlackSpace(p);
765 p = SkipWhiteSpace(p);
766 }
767
768 // allocate argument array
769 base::ScopedVector<char*> argv(argc);
770
771 // split the flags string into arguments
772 argc = 1; // be compatible with SetFlagsFromCommandLine()
773 for (char* p = copy; *p != '\0'; argc++) {
774 argv[argc] = p;
775 p = SkipBlackSpace(p);
776 if (*p != '\0') *p++ = '\0'; // 0-terminate argument
777 p = SkipWhiteSpace(p);
778 }
779
780 return SetFlagsFromCommandLine(&argc, argv.begin(), false);
781 }
782
783 // static
ResetAllFlags()784 void FlagList::ResetAllFlags() {
785 flag_hash = 0;
786 for (size_t i = 0; i < num_flags; ++i) {
787 flags[i].Reset();
788 }
789 }
790
791 // static
PrintHelp()792 void FlagList::PrintHelp() {
793 CpuFeatures::Probe(false);
794 CpuFeatures::PrintTarget();
795 CpuFeatures::PrintFeatures();
796
797 StdoutStream os;
798 os << "The following syntax for options is accepted (both '-' and '--' are "
799 "ok):\n"
800 " --flag (bool flags only)\n"
801 " --no-flag (bool flags only)\n"
802 " --flag=value (non-bool flags only, no spaces around '=')\n"
803 " --flag value (non-bool flags only)\n"
804 " -- (captures all remaining args in JavaScript)\n\n";
805 os << "Options:\n";
806
807 for (const Flag& f : flags) {
808 os << " --" << FlagName(f) << " (" << f.comment() << ")\n"
809 << " type: " << Type2String(f.type()) << " default: " << f
810 << "\n";
811 }
812 }
813
814 // static
PrintValues()815 void FlagList::PrintValues() {
816 StdoutStream os;
817 for (const Flag& f : flags) {
818 os << f << "\n";
819 }
820 }
821
822 namespace {
823
824 template <class A, class B>
TriggerImplication(bool premise,const char * premise_name,A * conclusion_pointer,B value,bool weak_implication)825 bool TriggerImplication(bool premise, const char* premise_name,
826 A* conclusion_pointer, B value, bool weak_implication) {
827 if (!premise) return false;
828 bool change_flag = *conclusion_pointer != implicit_cast<A>(value);
829 Flag* conclusion_flag = FindFlagByPointer(conclusion_pointer);
830 change_flag = conclusion_flag->CheckFlagChange(
831 weak_implication ? Flag::SetBy::kWeakImplication
832 : Flag::SetBy::kImplication,
833 change_flag, premise_name);
834 if (change_flag) *conclusion_pointer = value;
835 return change_flag;
836 }
837
838 } // namespace
839
840 // static
EnforceFlagImplications()841 void FlagList::EnforceFlagImplications() {
842 flag_hash = 0;
843 bool changed;
844 do {
845 changed = false;
846 #define FLAG_MODE_DEFINE_IMPLICATIONS
847 #include "src/flags/flag-definitions.h" // NOLINT(build/include)
848 #undef FLAG_MODE_DEFINE_IMPLICATIONS
849 } while (changed);
850 }
851
852 // static
Hash()853 uint32_t FlagList::Hash() {
854 if (flag_hash.load() == 0) ComputeFlagListHash();
855 return flag_hash.load();
856 }
857
858 #undef FLAG_MODE_DEFINE
859 #undef FLAG_MODE_DEFINE_DEFAULTS
860 #undef FLAG_MODE_META
861
862 } // namespace internal
863 } // namespace v8
864