// Copyright 2006-2008 the V8 project authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. #include "src/flags/flags.h" #include <cctype> #include <cerrno> #include <cinttypes> #include <cstdlib> #include <cstring> #include <sstream> #include "src/base/functional.h" #include "src/base/logging.h" #include "src/base/platform/platform.h" #include "src/codegen/cpu-features.h" #include "src/logging/counters.h" #include "src/utils/allocation.h" #include "src/utils/memcopy.h" #include "src/utils/ostreams.h" #include "src/utils/utils.h" #include "src/wasm/wasm-limits.h" namespace v8 { namespace internal { // Define all of our flags. #define FLAG_MODE_DEFINE #include "src/flags/flag-definitions.h" // NOLINT(build/include) // Define all of our flags default values. #define FLAG_MODE_DEFINE_DEFAULTS #include "src/flags/flag-definitions.h" // NOLINT(build/include) namespace { struct Flag; Flag* FindFlagByPointer(const void* ptr); Flag* FindFlagByName(const char* name); // This structure represents a single entry in the flag system, with a pointer // to the actual flag, default value, comment, etc. This is designed to be POD // initialized as to avoid requiring static constructors. struct Flag { enum FlagType { TYPE_BOOL, TYPE_MAYBE_BOOL, TYPE_INT, TYPE_UINT, TYPE_UINT64, TYPE_FLOAT, TYPE_SIZE_T, TYPE_STRING, }; enum class SetBy { kDefault, kWeakImplication, kImplication, kCommandLine }; FlagType type_; // What type of flag, bool, int, or string. const char* name_; // Name of the flag, ex "my_flag". void* valptr_; // Pointer to the global flag variable. const void* defptr_; // Pointer to the default value. const char* cmt_; // A comment about the flags purpose. bool owns_ptr_; // Does the flag own its string value? SetBy set_by_ = SetBy::kDefault; const char* implied_by_ = nullptr; FlagType type() const { return type_; } const char* name() const { return name_; } const char* comment() const { return cmt_; } bool PointsTo(const void* ptr) const { return valptr_ == ptr; } bool bool_variable() const { DCHECK(type_ == TYPE_BOOL); return *reinterpret_cast<bool*>(valptr_); } void set_bool_variable(bool value, SetBy set_by) { DCHECK(type_ == TYPE_BOOL); bool change_flag = *reinterpret_cast<bool*>(valptr_) != value; change_flag = CheckFlagChange(set_by, change_flag); if (change_flag) *reinterpret_cast<bool*>(valptr_) = value; } MaybeBoolFlag maybe_bool_variable() const { DCHECK(type_ == TYPE_MAYBE_BOOL); return *reinterpret_cast<MaybeBoolFlag*>(valptr_); } void set_maybe_bool_variable(MaybeBoolFlag value, SetBy set_by) { DCHECK(type_ == TYPE_MAYBE_BOOL); bool change_flag = *reinterpret_cast<MaybeBoolFlag*>(valptr_) != value; change_flag = CheckFlagChange(set_by, change_flag); if (change_flag) *reinterpret_cast<MaybeBoolFlag*>(valptr_) = value; } int int_variable() const { DCHECK(type_ == TYPE_INT); return *reinterpret_cast<int*>(valptr_); } void set_int_variable(int value, SetBy set_by) { DCHECK(type_ == TYPE_INT); bool change_flag = *reinterpret_cast<int*>(valptr_) != value; change_flag = CheckFlagChange(set_by, change_flag); if (change_flag) *reinterpret_cast<int*>(valptr_) = value; } unsigned int uint_variable() const { DCHECK(type_ == TYPE_UINT); return *reinterpret_cast<unsigned int*>(valptr_); } void set_uint_variable(unsigned int value, SetBy set_by) { DCHECK(type_ == TYPE_UINT); bool change_flag = *reinterpret_cast<unsigned int*>(valptr_) != value; change_flag = CheckFlagChange(set_by, change_flag); if (change_flag) *reinterpret_cast<unsigned int*>(valptr_) = value; } uint64_t uint64_variable() const { DCHECK(type_ == TYPE_UINT64); return *reinterpret_cast<uint64_t*>(valptr_); } void set_uint64_variable(uint64_t value, SetBy set_by) { DCHECK(type_ == TYPE_UINT64); bool change_flag = *reinterpret_cast<uint64_t*>(valptr_) != value; change_flag = CheckFlagChange(set_by, change_flag); if (change_flag) *reinterpret_cast<uint64_t*>(valptr_) = value; } double float_variable() const { DCHECK(type_ == TYPE_FLOAT); return *reinterpret_cast<double*>(valptr_); } void set_float_variable(double value, SetBy set_by) { DCHECK(type_ == TYPE_FLOAT); bool change_flag = *reinterpret_cast<double*>(valptr_) != value; change_flag = CheckFlagChange(set_by, change_flag); if (change_flag) *reinterpret_cast<double*>(valptr_) = value; } size_t size_t_variable() const { DCHECK(type_ == TYPE_SIZE_T); return *reinterpret_cast<size_t*>(valptr_); } void set_size_t_variable(size_t value, SetBy set_by) { DCHECK(type_ == TYPE_SIZE_T); bool change_flag = *reinterpret_cast<size_t*>(valptr_) != value; change_flag = CheckFlagChange(set_by, change_flag); if (change_flag) *reinterpret_cast<size_t*>(valptr_) = value; } const char* string_value() const { DCHECK(type_ == TYPE_STRING); return *reinterpret_cast<const char**>(valptr_); } void set_string_value(const char* value, bool owns_ptr, SetBy set_by) { DCHECK(type_ == TYPE_STRING); const char** ptr = reinterpret_cast<const char**>(valptr_); bool change_flag = (*ptr == nullptr) != (value == nullptr) || (*ptr && value && std::strcmp(*ptr, value) != 0); change_flag = CheckFlagChange(set_by, change_flag); if (change_flag) { if (owns_ptr_ && *ptr != nullptr) DeleteArray(*ptr); *ptr = value; owns_ptr_ = owns_ptr; } else { if (owns_ptr && value != nullptr) DeleteArray(value); } } bool bool_default() const { DCHECK(type_ == TYPE_BOOL); return *reinterpret_cast<const bool*>(defptr_); } int int_default() const { DCHECK(type_ == TYPE_INT); return *reinterpret_cast<const int*>(defptr_); } unsigned int uint_default() const { DCHECK(type_ == TYPE_UINT); return *reinterpret_cast<const unsigned int*>(defptr_); } uint64_t uint64_default() const { DCHECK(type_ == TYPE_UINT64); return *reinterpret_cast<const uint64_t*>(defptr_); } double float_default() const { DCHECK(type_ == TYPE_FLOAT); return *reinterpret_cast<const double*>(defptr_); } size_t size_t_default() const { DCHECK(type_ == TYPE_SIZE_T); return *reinterpret_cast<const size_t*>(defptr_); } const char* string_default() const { DCHECK(type_ == TYPE_STRING); return *reinterpret_cast<const char* const*>(defptr_); } static bool ShouldCheckFlagContradictions() { if (FLAG_allow_overwriting_for_next_flag) { // Setting the flag manually to false before calling Reset() avoids this // becoming re-entrant. FLAG_allow_overwriting_for_next_flag = false; FindFlagByPointer(&FLAG_allow_overwriting_for_next_flag)->Reset(); return false; } return FLAG_abort_on_contradictory_flags && !FLAG_fuzzing; } // {change_flag} indicates if we're going to change the flag value. // Returns an updated value for {change_flag}, which is changed to false if a // weak implication is being ignored beause a flag is already set by a normal // implication or from the command-line. bool CheckFlagChange(SetBy new_set_by, bool change_flag, const char* implied_by = nullptr) { if (new_set_by == SetBy::kWeakImplication && (set_by_ == SetBy::kImplication || set_by_ == SetBy::kCommandLine)) { return false; } if (ShouldCheckFlagContradictions()) { // For bool flags, we only check for a conflict if the value actually // changes. So specifying the same flag with the same value multiple times // is allowed. // For other flags, we disallow specifying them explicitly or in the // presence of an implication even if the value is the same. // This is to simplify the rules describing conflicts in variants.py: A // repeated non-boolean flag is considered an error independently of its // value. bool is_bool_flag = type_ == TYPE_MAYBE_BOOL || type_ == TYPE_BOOL; bool check_implications = change_flag; bool check_command_line_flags = change_flag || !is_bool_flag; const char* hint = "To fix this, it might be necessary to specify additional " "contradictory flags in tools/testrunner/local/variants.py."; switch (set_by_) { case SetBy::kDefault: break; case SetBy::kWeakImplication: if (new_set_by == SetBy::kWeakImplication && check_implications) { FATAL( "Contradictory weak flag implications from --%s and --%s for " "flag %s\n%s", implied_by_, implied_by, name(), hint); } break; case SetBy::kImplication: if (new_set_by == SetBy::kImplication && check_implications) { FATAL( "Contradictory flag implications from --%s and --%s for flag " "%s\n%s", implied_by_, implied_by, name(), hint); } break; case SetBy::kCommandLine: if (new_set_by == SetBy::kImplication && check_command_line_flags) { if (is_bool_flag) { FATAL( "Flag --%s: value implied by --%s conflicts with explicit " "specification\n%s", name(), implied_by, hint); } else { FATAL( "Flag --%s is implied by --%s but also specified " "explicitly.\n%s", name(), implied_by, hint); } } else if (new_set_by == SetBy::kCommandLine && check_command_line_flags) { if (is_bool_flag) { FATAL( "Command-line provided flag --%s specified as both true and " "false.\n%s", name(), hint); } else { FATAL( "Command-line provided flag --%s specified multiple " "times.\n%s", name(), hint); } } break; } } set_by_ = new_set_by; if (new_set_by == SetBy::kImplication || new_set_by == SetBy::kWeakImplication) { DCHECK_NOT_NULL(implied_by); implied_by_ = implied_by; } return change_flag; } // Compare this flag's current value against the default. bool IsDefault() const { switch (type_) { case TYPE_BOOL: return bool_variable() == bool_default(); case TYPE_MAYBE_BOOL: return maybe_bool_variable().has_value == false; case TYPE_INT: return int_variable() == int_default(); case TYPE_UINT: return uint_variable() == uint_default(); case TYPE_UINT64: return uint64_variable() == uint64_default(); case TYPE_FLOAT: return float_variable() == float_default(); case TYPE_SIZE_T: return size_t_variable() == size_t_default(); case TYPE_STRING: { const char* str1 = string_value(); const char* str2 = string_default(); if (str2 == nullptr) return str1 == nullptr; if (str1 == nullptr) return str2 == nullptr; return strcmp(str1, str2) == 0; } } UNREACHABLE(); } // Set a flag back to it's default value. void Reset() { switch (type_) { case TYPE_BOOL: set_bool_variable(bool_default(), SetBy::kDefault); break; case TYPE_MAYBE_BOOL: set_maybe_bool_variable(MaybeBoolFlag::Create(false, false), SetBy::kDefault); break; case TYPE_INT: set_int_variable(int_default(), SetBy::kDefault); break; case TYPE_UINT: set_uint_variable(uint_default(), SetBy::kDefault); break; case TYPE_UINT64: set_uint64_variable(uint64_default(), SetBy::kDefault); break; case TYPE_FLOAT: set_float_variable(float_default(), SetBy::kDefault); break; case TYPE_SIZE_T: set_size_t_variable(size_t_default(), SetBy::kDefault); break; case TYPE_STRING: set_string_value(string_default(), false, SetBy::kDefault); break; } } void AllowOverwriting() { set_by_ = SetBy::kDefault; } }; Flag flags[] = { #define FLAG_MODE_META #include "src/flags/flag-definitions.h" // NOLINT(build/include) }; const size_t num_flags = sizeof(flags) / sizeof(*flags); inline char NormalizeChar(char ch) { return ch == '_' ? '-' : ch; } bool EqualNames(const char* a, const char* b) { for (int i = 0; NormalizeChar(a[i]) == NormalizeChar(b[i]); i++) { if (a[i] == '\0') { return true; } } return false; } Flag* FindFlagByName(const char* name) { for (size_t i = 0; i < num_flags; ++i) { if (EqualNames(name, flags[i].name())) return &flags[i]; } return nullptr; } Flag* FindFlagByPointer(const void* ptr) { for (size_t i = 0; i < num_flags; ++i) { if (flags[i].PointsTo(ptr)) return &flags[i]; } return nullptr; } } // namespace static const char* Type2String(Flag::FlagType type) { switch (type) { case Flag::TYPE_BOOL: return "bool"; case Flag::TYPE_MAYBE_BOOL: return "maybe_bool"; case Flag::TYPE_INT: return "int"; case Flag::TYPE_UINT: return "uint"; case Flag::TYPE_UINT64: return "uint64"; case Flag::TYPE_FLOAT: return "float"; case Flag::TYPE_SIZE_T: return "size_t"; case Flag::TYPE_STRING: return "string"; } UNREACHABLE(); } std::ostream& operator<<(std::ostream& os, const Flag& flag) { // NOLINT switch (flag.type()) { case Flag::TYPE_BOOL: os << (flag.bool_variable() ? "true" : "false"); break; case Flag::TYPE_MAYBE_BOOL: os << (flag.maybe_bool_variable().has_value ? (flag.maybe_bool_variable().value ? "true" : "false") : "unset"); break; case Flag::TYPE_INT: os << flag.int_variable(); break; case Flag::TYPE_UINT: os << flag.uint_variable(); break; case Flag::TYPE_UINT64: os << flag.uint64_variable(); break; case Flag::TYPE_FLOAT: os << flag.float_variable(); break; case Flag::TYPE_SIZE_T: os << flag.size_t_variable(); break; case Flag::TYPE_STRING: { const char* str = flag.string_value(); os << (str ? str : "nullptr"); break; } } return os; } // static std::vector<const char*>* FlagList::argv() { std::vector<const char*>* args = new std::vector<const char*>(8); for (size_t i = 0; i < num_flags; ++i) { Flag* f = &flags[i]; if (!f->IsDefault()) { { bool disabled = f->type() == Flag::TYPE_BOOL && !f->bool_variable(); std::ostringstream os; os << (disabled ? "--no" : "--") << f->name(); args->push_back(StrDup(os.str().c_str())); } if (f->type() != Flag::TYPE_BOOL) { std::ostringstream os; os << *f; args->push_back(StrDup(os.str().c_str())); } } } return args; } // Helper function to parse flags: Takes an argument arg and splits it into // a flag name and flag value (or nullptr if they are missing). negated is set // if the arg started with "-no" or "--no". The buffer may be used to NUL- // terminate the name, it must be large enough to hold any possible name. static void SplitArgument(const char* arg, char* buffer, int buffer_size, const char** name, const char** value, bool* negated) { *name = nullptr; *value = nullptr; *negated = false; if (arg != nullptr && *arg == '-') { // find the begin of the flag name arg++; // remove 1st '-' if (*arg == '-') { arg++; // remove 2nd '-' DCHECK_NE('\0', arg[0]); // '--' arguments are handled in the caller. } if (arg[0] == 'n' && arg[1] == 'o') { arg += 2; // remove "no" if (NormalizeChar(arg[0]) == '-') arg++; // remove dash after "no". *negated = true; } *name = arg; // find the end of the flag name while (*arg != '\0' && *arg != '=') arg++; // get the value if any if (*arg == '=') { // make a copy so we can NUL-terminate flag name size_t n = arg - *name; CHECK(n < static_cast<size_t>(buffer_size)); // buffer is too small MemCopy(buffer, *name, n); buffer[n] = '\0'; *name = buffer; // get the value *value = arg + 1; } } } template <typename T> bool TryParseUnsigned(Flag* flag, const char* arg, const char* value, char** endp, T* out_val) { // We do not use strtoul because it accepts negative numbers. // Rejects values >= 2**63 when T is 64 bits wide but that // seems like an acceptable trade-off. uint64_t max = static_cast<uint64_t>(std::numeric_limits<T>::max()); errno = 0; int64_t val = static_cast<int64_t>(strtoll(value, endp, 10)); if (val < 0 || static_cast<uint64_t>(val) > max || errno != 0) { PrintF(stderr, "Error: Value for flag %s of type %s is out of bounds " "[0-%" PRIu64 "]\n", arg, Type2String(flag->type()), max); return false; } *out_val = static_cast<T>(val); return true; } // static int FlagList::SetFlagsFromCommandLine(int* argc, char** argv, bool remove_flags, HelpOptions help_options) { int return_code = 0; // parse arguments for (int i = 1; i < *argc;) { int j = i; // j > 0 const char* arg = argv[i++]; // split arg into flag components char buffer[1 * KB]; const char* name; const char* value; bool negated; SplitArgument(arg, buffer, sizeof buffer, &name, &value, &negated); if (name != nullptr) { // lookup the flag Flag* flag = FindFlagByName(name); if (flag == nullptr) { if (remove_flags) { // We don't recognize this flag but since we're removing // the flags we recognize we assume that the remaining flags // will be processed somewhere else so this flag might make // sense there. continue; } else { PrintF(stderr, "Error: unrecognized flag %s\n", arg); return_code = j; break; } } // if we still need a flag value, use the next argument if available if (flag->type() != Flag::TYPE_BOOL && flag->type() != Flag::TYPE_MAYBE_BOOL && value == nullptr) { if (i < *argc) { value = argv[i++]; } if (!value) { PrintF(stderr, "Error: missing value for flag %s of type %s\n", arg, Type2String(flag->type())); return_code = j; break; } } // set the flag char* endp = const_cast<char*>(""); // *endp is only read switch (flag->type()) { case Flag::TYPE_BOOL: flag->set_bool_variable(!negated, Flag::SetBy::kCommandLine); break; case Flag::TYPE_MAYBE_BOOL: flag->set_maybe_bool_variable(MaybeBoolFlag::Create(true, !negated), Flag::SetBy::kCommandLine); break; case Flag::TYPE_INT: flag->set_int_variable(static_cast<int>(strtol(value, &endp, 10)), Flag::SetBy::kCommandLine); break; case Flag::TYPE_UINT: { unsigned int parsed_value; if (TryParseUnsigned(flag, arg, value, &endp, &parsed_value)) { flag->set_uint_variable(parsed_value, Flag::SetBy::kCommandLine); } else { return_code = j; } break; } case Flag::TYPE_UINT64: { uint64_t parsed_value; if (TryParseUnsigned(flag, arg, value, &endp, &parsed_value)) { flag->set_uint64_variable(parsed_value, Flag::SetBy::kCommandLine); } else { return_code = j; } break; } case Flag::TYPE_FLOAT: flag->set_float_variable(strtod(value, &endp), Flag::SetBy::kCommandLine); break; case Flag::TYPE_SIZE_T: { size_t parsed_value; if (TryParseUnsigned(flag, arg, value, &endp, &parsed_value)) { flag->set_size_t_variable(parsed_value, Flag::SetBy::kCommandLine); } else { return_code = j; } break; } case Flag::TYPE_STRING: flag->set_string_value(value ? StrDup(value) : nullptr, true, Flag::SetBy::kCommandLine); break; } // handle errors bool is_bool_type = flag->type() == Flag::TYPE_BOOL || flag->type() == Flag::TYPE_MAYBE_BOOL; if ((is_bool_type && value != nullptr) || (!is_bool_type && negated) || *endp != '\0') { // TODO(neis): TryParseUnsigned may return with {*endp == '\0'} even in // an error case. PrintF(stderr, "Error: illegal value for flag %s of type %s\n", arg, Type2String(flag->type())); if (is_bool_type) { PrintF(stderr, "To set or unset a boolean flag, use --flag or --no-flag.\n"); } return_code = j; break; } // remove the flag & value from the command if (remove_flags) { while (j < i) { argv[j++] = nullptr; } } } } if (FLAG_help) { if (help_options.HasUsage()) { PrintF(stdout, "%s", help_options.usage()); } PrintHelp(); if (help_options.ShouldExit()) { exit(0); } } if (remove_flags) { // shrink the argument list int j = 1; for (int i = 1; i < *argc; i++) { if (argv[i] != nullptr) argv[j++] = argv[i]; } *argc = j; } else if (return_code != 0) { if (return_code + 1 < *argc) { PrintF(stderr, "The remaining arguments were ignored:"); for (int i = return_code + 1; i < *argc; ++i) { PrintF(stderr, " %s", argv[i]); } PrintF(stderr, "\n"); } } if (return_code != 0) PrintF(stderr, "Try --help for options\n"); return return_code; } static char* SkipWhiteSpace(char* p) { while (*p != '\0' && isspace(*p) != 0) p++; return p; } static char* SkipBlackSpace(char* p) { while (*p != '\0' && isspace(*p) == 0) p++; return p; } // static int FlagList::SetFlagsFromString(const char* str, size_t len) { // make a 0-terminated copy of str std::unique_ptr<char[]> copy0{NewArray<char>(len + 1)}; MemCopy(copy0.get(), str, len); copy0[len] = '\0'; // strip leading white space char* copy = SkipWhiteSpace(copy0.get()); // count the number of 'arguments' int argc = 1; // be compatible with SetFlagsFromCommandLine() for (char* p = copy; *p != '\0'; argc++) { p = SkipBlackSpace(p); p = SkipWhiteSpace(p); } // allocate argument array ScopedVector<char*> argv(argc); // split the flags string into arguments argc = 1; // be compatible with SetFlagsFromCommandLine() for (char* p = copy; *p != '\0'; argc++) { argv[argc] = p; p = SkipBlackSpace(p); if (*p != '\0') *p++ = '\0'; // 0-terminate argument p = SkipWhiteSpace(p); } return SetFlagsFromCommandLine(&argc, argv.begin(), false); } // static void FlagList::ResetAllFlags() { for (size_t i = 0; i < num_flags; ++i) { flags[i].Reset(); } } // static void FlagList::PrintHelp() { CpuFeatures::Probe(false); CpuFeatures::PrintTarget(); CpuFeatures::PrintFeatures(); StdoutStream os; os << "The following syntax for options is accepted (both '-' and '--' are " "ok):\n" " --flag (bool flags only)\n" " --no-flag (bool flags only)\n" " --flag=value (non-bool flags only, no spaces around '=')\n" " --flag value (non-bool flags only)\n" " -- (captures all remaining args in JavaScript)\n\n"; os << "Options:\n"; for (const Flag& f : flags) { os << " --"; for (const char* c = f.name(); *c != '\0'; ++c) { os << NormalizeChar(*c); } os << " (" << f.comment() << ")\n" << " type: " << Type2String(f.type()) << " default: " << f << "\n"; } } namespace { static uint32_t flag_hash = 0; void ComputeFlagListHash() { std::ostringstream modified_args_as_string; if (COMPRESS_POINTERS_BOOL) { modified_args_as_string << "ptr-compr"; } if (DEBUG_BOOL) { modified_args_as_string << "debug"; } for (size_t i = 0; i < num_flags; ++i) { Flag* current = &flags[i]; if (current->PointsTo(&FLAG_profile_deserialization)) { // We want to be able to flip --profile-deserialization without // causing the code cache to get invalidated by this hash. continue; } if (!current->IsDefault()) { modified_args_as_string << i; modified_args_as_string << *current; } } std::string args(modified_args_as_string.str()); flag_hash = static_cast<uint32_t>( base::hash_range(args.c_str(), args.c_str() + args.length())); } template <class A, class B> bool TriggerImplication(bool premise, const char* premise_name, A* conclusion_pointer, B value, bool weak_implication) { if (!premise) return false; bool change_flag = *conclusion_pointer != implicit_cast<A>(value); Flag* conclusion_flag = FindFlagByPointer(conclusion_pointer); change_flag = conclusion_flag->CheckFlagChange( weak_implication ? Flag::SetBy::kWeakImplication : Flag::SetBy::kImplication, change_flag, premise_name); if (change_flag) *conclusion_pointer = value; return change_flag; } } // namespace // static void FlagList::EnforceFlagImplications() { bool changed; do { changed = false; #define FLAG_MODE_DEFINE_IMPLICATIONS #include "src/flags/flag-definitions.h" // NOLINT(build/include) #undef FLAG_MODE_DEFINE_IMPLICATIONS } while (changed); ComputeFlagListHash(); } uint32_t FlagList::Hash() { return flag_hash; } #undef FLAG_MODE_DEFINE #undef FLAG_MODE_DEFINE_DEFAULTS #undef FLAG_MODE_META } // namespace internal } // namespace v8