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Unified Diff: third_party/re2/re2/dfa.cc

Issue 1516543002: Update re2 (Closed) Base URL: https://chromium.googlesource.com/chromium/src.git@master
Patch Set: Update instructions Created 5 years ago
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Index: third_party/re2/re2/dfa.cc
diff --git a/third_party/re2/re2/dfa.cc b/third_party/re2/re2/dfa.cc
index f1fc7b0caf1b57570b2a81f1cfd6ee6b766bd36b..1f54b9f942eb4804cc89a9ce3e6dadb75c3caf3f 100644
--- a/third_party/re2/re2/dfa.cc
+++ b/third_party/re2/re2/dfa.cc
@@ -21,13 +21,11 @@
//
// See http://swtch.com/~rsc/regexp/ for a very bare-bones equivalent.
-#include "re2/prog.h"
-#include "re2/stringpiece.h"
#include "util/atomicops.h"
#include "util/flags.h"
#include "util/sparse_set.h"
-
-#define NO_THREAD_SAFETY_ANALYSIS
+#include "re2/prog.h"
+#include "re2/stringpiece.h"
DEFINE_bool(re2_dfa_bail_when_slow, true,
"Whether the RE2 DFA should bail out early "
@@ -96,7 +94,7 @@ class DFA {
// States, linked by the next_ pointers. If in state s and reading
// byte c, the next state should be s->next_[c].
struct State {
- inline bool IsMatch() const { return flag_ & kFlagMatch; }
+ inline bool IsMatch() const { return (flag_ & kFlagMatch) != 0; }
void SaveMatch(vector<int>* v);
int* inst_; // Instruction pointers in the state.
@@ -145,7 +143,7 @@ class DFA {
if (sizeof(size_t) == sizeof(uint32))
return Hash32StringWithSeed(s, len, a->flag_);
else
- return Hash64StringWithSeed(s, len, a->flag_);
+ return static_cast<size_t>(Hash64StringWithSeed(s, len, a->flag_));
}
#ifdef STL_MSVC
// Less than operator.
@@ -230,9 +228,8 @@ class DFA {
// sets *ismatch to true.
// L >= mutex_
void RunWorkqOnByte(Workq* q, Workq* nq,
- int c, uint flag, bool* ismatch,
- Prog::MatchKind kind,
- int new_byte_loop);
+ int c, uint flag, bool* ismatch,
+ Prog::MatchKind kind);
// Runs a Workq on a set of empty-string flags, producing a new Workq in nq.
// L >= mutex_
@@ -277,7 +274,7 @@ class DFA {
vector<int>* matches;
private:
- DISALLOW_EVIL_CONSTRUCTORS(SearchParams);
+ DISALLOW_COPY_AND_ASSIGN(SearchParams);
};
// Before each search, the parameters to Search are analyzed by
@@ -342,7 +339,6 @@ class DFA {
// Constant after initialization.
Prog* prog_; // The regular expression program to run.
Prog::MatchKind kind_; // The kind of DFA.
- int start_unanchored_; // start of unanchored program
bool init_failed_; // initialization failed (out of memory)
Mutex mutex_; // mutex_ >= cache_mutex_.r
@@ -430,7 +426,7 @@ class DFA::Workq : public SparseSet {
int maxmark_; // maximum number of marks
int nextmark_; // id of next mark
bool last_was_mark_; // last inserted was mark
- DISALLOW_EVIL_CONSTRUCTORS(Workq);
+ DISALLOW_COPY_AND_ASSIGN(Workq);
};
DFA::DFA(Prog* prog, Prog::MatchKind kind, int64 max_mem)
@@ -445,11 +441,8 @@ DFA::DFA(Prog* prog, Prog::MatchKind kind, int64 max_mem)
if (DebugDFA)
fprintf(stderr, "\nkind %d\n%s\n", (int)kind_, prog_->DumpUnanchored().c_str());
int nmark = 0;
- start_unanchored_ = 0;
- if (kind_ == Prog::kLongestMatch) {
+ if (kind_ == Prog::kLongestMatch)
nmark = prog->size();
- start_unanchored_ = prog->start_unanchored();
- }
nastack_ = 2 * prog->size() + nmark;
// Account for space needed for DFA, q0, q1, astack.
@@ -458,7 +451,7 @@ DFA::DFA(Prog* prog, Prog::MatchKind kind, int64 max_mem)
(sizeof(int)+sizeof(int)) * 2; // q0, q1
mem_budget_ -= nastack_ * sizeof(int); // astack
if (mem_budget_ < 0) {
- LOG(INFO) << StringPrintf("DFA out of memory: prog size %lld mem %lld",
+ LOG(INFO) << StringPrintf("DFA out of memory: prog size %d mem %lld",
prog_->size(), max_mem);
init_failed_ = true;
return;
@@ -473,7 +466,7 @@ DFA::DFA(Prog* prog, Prog::MatchKind kind, int64 max_mem)
int64 one_state = sizeof(State) + (prog_->size()+nmark)*sizeof(int) +
(prog_->bytemap_range()+1)*sizeof(State*);
if (state_budget_ < 20*one_state) {
- LOG(INFO) << StringPrintf("DFA out of memory: prog size %lld mem %lld",
+ LOG(INFO) << StringPrintf("DFA out of memory: prog size %d mem %lld",
prog_->size(), max_mem);
init_failed_ = true;
return;
@@ -789,7 +782,7 @@ void DFA::ClearCache() {
it != state_cache_.end(); ++it)
v.push_back(*it);
state_cache_.clear();
- for (int i = 0; i < v.size(); i++)
+ for (size_t i = 0; i < v.size(); i++)
delete[] reinterpret_cast<const char*>(v[i]);
}
@@ -871,8 +864,10 @@ void DFA::AddToQueue(Workq* q, int id, uint flag) {
break;
case kInstEmptyWidth:
- if ((ip->empty() & flag) == ip->empty())
- stk[nstk++] = ip->out();
+ // Continue on if we have all the right flag bits.
+ if (ip->empty() & ~flag)
+ break;
+ stk[nstk++] = ip->out();
break;
}
}
@@ -910,8 +905,7 @@ void DFA::RunWorkqOnEmptyString(Workq* oldq, Workq* newq, uint flag) {
// regular expression program has been reached (the regexp has matched).
void DFA::RunWorkqOnByte(Workq* oldq, Workq* newq,
int c, uint flag, bool* ismatch,
- Prog::MatchKind kind,
- int new_byte_loop) {
+ Prog::MatchKind kind) {
if (DEBUG_MODE)
mutex_.AssertHeld();
@@ -990,9 +984,8 @@ DFA::State* DFA::RunStateOnByte(State* state, int c) {
}
// If someone else already computed this, return it.
- MaybeReadMemoryBarrier(); // On alpha we need to ensure read ordering
- State* ns = state->next_[ByteMap(c)];
- ANNOTATE_HAPPENS_AFTER(ns);
+ State* ns;
+ ATOMIC_LOAD_CONSUME(ns, &state->next_[ByteMap(c)]);
if (ns != NULL)
return ns;
@@ -1022,8 +1015,8 @@ DFA::State* DFA::RunStateOnByte(State* state, int c) {
// The state flag kFlagLastWord says whether the last
// byte processed was a word character. Use that info to
// insert empty-width (non-)word boundaries.
- bool islastword = state->flag_ & kFlagLastWord;
- bool isword = (c != kByteEndText && Prog::IsWordChar(c));
+ bool islastword = (state->flag_ & kFlagLastWord) != 0;
+ bool isword = (c != kByteEndText && Prog::IsWordChar(static_cast<uint8>(c)));
if (isword == islastword)
beforeflag |= kEmptyNonWordBoundary;
else
@@ -1036,8 +1029,8 @@ DFA::State* DFA::RunStateOnByte(State* state, int c) {
swap(q0_, q1_);
}
bool ismatch = false;
- RunWorkqOnByte(q0_, q1_, c, afterflag, &ismatch, kind_, start_unanchored_);
-
+ RunWorkqOnByte(q0_, q1_, c, afterflag, &ismatch, kind_);
+
// Most of the time, we build the state from the output of
// RunWorkqOnByte, so swap q0_ and q1_ here. However, so that
// RE2::Set can tell exactly which match instructions
@@ -1058,18 +1051,11 @@ DFA::State* DFA::RunStateOnByte(State* state, int c) {
ns = WorkqToCachedState(q0_, flag);
+ // Flush ns before linking to it.
// Write barrier before updating state->next_ so that the
// main search loop can proceed without any locking, for speed.
// (Otherwise it would need one mutex operation per input byte.)
- // The annotations below tell race detectors that:
- // a) the access to next_ should be ignored,
- // b) 'ns' is properly published.
- WriteMemoryBarrier(); // Flush ns before linking to it.
-
- ANNOTATE_IGNORE_WRITES_BEGIN();
- ANNOTATE_HAPPENS_BEFORE(ns);
- state->next_[ByteMap(c)] = ns;
- ANNOTATE_IGNORE_WRITES_END();
+ ATOMIC_STORE_RELEASE(&state->next_[ByteMap(c)], ns);
return ns;
}
@@ -1112,7 +1098,7 @@ class DFA::RWLocker {
Mutex* mu_;
bool writing_;
- DISALLOW_EVIL_CONSTRUCTORS(RWLocker);
+ DISALLOW_COPY_AND_ASSIGN(RWLocker);
};
DFA::RWLocker::RWLocker(Mutex* mu)
@@ -1212,7 +1198,7 @@ class DFA::StateSaver {
bool is_special_; // whether original state was special
State* special_; // if is_special_, the original state
- DISALLOW_EVIL_CONSTRUCTORS(StateSaver);
+ DISALLOW_COPY_AND_ASSIGN(StateSaver);
};
DFA::StateSaver::StateSaver(DFA* dfa, State* state) {
@@ -1390,9 +1376,8 @@ inline bool DFA::InlinedSearchLoop(SearchParams* params,
// Okay to use bytemap[] not ByteMap() here, because
// c is known to be an actual byte and not kByteEndText.
- MaybeReadMemoryBarrier(); // On alpha we need to ensure read ordering
- State* ns = s->next_[bytemap[c]];
- ANNOTATE_HAPPENS_AFTER(ns);
+ State* ns;
+ ATOMIC_LOAD_CONSUME(ns, &s->next_[bytemap[c]]);
if (ns == NULL) {
ns = RunStateOnByteUnlocked(s, c);
if (ns == NULL) {
@@ -1405,7 +1390,7 @@ inline bool DFA::InlinedSearchLoop(SearchParams* params,
// of 10 bytes per state computation, fail so that RE2 can
// fall back to the NFA.
if (FLAGS_re2_dfa_bail_when_slow && resetp != NULL &&
- (p - resetp) < 10*state_cache_.size()) {
+ static_cast<unsigned long>(p - resetp) < 10*state_cache_.size()) {
params->failed = true;
return false;
}
@@ -1479,9 +1464,8 @@ inline bool DFA::InlinedSearchLoop(SearchParams* params,
lastbyte = params->text.begin()[-1] & 0xFF;
}
- MaybeReadMemoryBarrier(); // On alpha we need to ensure read ordering
- State* ns = s->next_[ByteMap(lastbyte)];
- ANNOTATE_HAPPENS_AFTER(ns);
+ State* ns;
+ ATOMIC_LOAD_CONSUME(ns, &s->next_[ByteMap(lastbyte)]);
if (ns == NULL) {
ns = RunStateOnByteUnlocked(s, lastbyte);
if (ns == NULL) {
@@ -1669,13 +1653,16 @@ bool DFA::AnalyzeSearch(SearchParams* params) {
}
}
- if (DebugDFA)
+ if (DebugDFA) {
+ int fb;
+ ATOMIC_LOAD_RELAXED(fb, &info->firstbyte);
fprintf(stderr, "anchored=%d fwd=%d flags=%#x state=%s firstbyte=%d\n",
params->anchored, params->run_forward, flags,
- DumpState(info->start).c_str(), info->firstbyte);
+ DumpState(info->start).c_str(), fb);
+ }
params->start = info->start;
- params->firstbyte = ANNOTATE_UNPROTECTED_READ(info->firstbyte);
+ ATOMIC_LOAD_ACQUIRE(params->firstbyte, &info->firstbyte);
return true;
}
@@ -1683,17 +1670,15 @@ bool DFA::AnalyzeSearch(SearchParams* params) {
// Fills in info if needed. Returns true on success, false on failure.
bool DFA::AnalyzeSearchHelper(SearchParams* params, StartInfo* info,
uint flags) {
- // Quick check; okay because of memory barriers below.
- if (ANNOTATE_UNPROTECTED_READ(info->firstbyte) != kFbUnknown) {
- ANNOTATE_HAPPENS_AFTER(&info->firstbyte);
+ // Quick check.
+ int fb;
+ ATOMIC_LOAD_ACQUIRE(fb, &info->firstbyte);
+ if (fb != kFbUnknown)
return true;
- }
MutexLock l(&mutex_);
- if (info->firstbyte != kFbUnknown) {
- ANNOTATE_HAPPENS_AFTER(&info->firstbyte);
+ if (info->firstbyte != kFbUnknown)
return true;
- }
q0_->clear();
AddToQueue(q0_,
@@ -1704,16 +1689,14 @@ bool DFA::AnalyzeSearchHelper(SearchParams* params, StartInfo* info,
return false;
if (info->start == DeadState) {
- ANNOTATE_HAPPENS_BEFORE(&info->firstbyte);
- WriteMemoryBarrier(); // Synchronize with "quick check" above.
- info->firstbyte = kFbNone;
+ // Synchronize with "quick check" above.
+ ATOMIC_STORE_RELEASE(&info->firstbyte, kFbNone);
return true;
}
if (info->start == FullMatchState) {
- ANNOTATE_HAPPENS_BEFORE(&info->firstbyte);
- WriteMemoryBarrier(); // Synchronize with "quick check" above.
- info->firstbyte = kFbNone; // will be ignored
+ // Synchronize with "quick check" above.
+ ATOMIC_STORE_RELEASE(&info->firstbyte, kFbNone); // will be ignored
return true;
}
@@ -1724,9 +1707,8 @@ bool DFA::AnalyzeSearchHelper(SearchParams* params, StartInfo* info,
for (int i = 0; i < 256; i++) {
State* s = RunStateOnByte(info->start, i);
if (s == NULL) {
- ANNOTATE_HAPPENS_BEFORE(&info->firstbyte);
- WriteMemoryBarrier(); // Synchronize with "quick check" above.
- info->firstbyte = firstbyte;
+ // Synchronize with "quick check" above.
+ ATOMIC_STORE_RELEASE(&info->firstbyte, firstbyte);
return false;
}
if (s == info->start)
@@ -1739,9 +1721,8 @@ bool DFA::AnalyzeSearchHelper(SearchParams* params, StartInfo* info,
break;
}
}
- ANNOTATE_HAPPENS_BEFORE(&info->firstbyte);
- WriteMemoryBarrier(); // Synchronize with "quick check" above.
- info->firstbyte = firstbyte;
+ // Synchronize with "quick check" above.
+ ATOMIC_STORE_RELEASE(&info->firstbyte, firstbyte);
return true;
}
@@ -1821,19 +1802,16 @@ DFA* Prog::GetDFA(MatchKind kind) {
pdfa = &dfa_longest_;
}
- // Quick check; okay because of memory barrier below.
- DFA *dfa = ANNOTATE_UNPROTECTED_READ(*pdfa);
- if (dfa != NULL) {
- ANNOTATE_HAPPENS_AFTER(dfa);
+ // Quick check.
+ DFA *dfa;
+ ATOMIC_LOAD_ACQUIRE(dfa, pdfa);
+ if (dfa != NULL)
return dfa;
- }
MutexLock l(&dfa_mutex_);
dfa = *pdfa;
- if (dfa != NULL) {
- ANNOTATE_HAPPENS_AFTER(dfa);
+ if (dfa != NULL)
return dfa;
- }
// For a forward DFA, half the memory goes to each DFA.
// For a reverse DFA, all the memory goes to the
@@ -1850,9 +1828,7 @@ DFA* Prog::GetDFA(MatchKind kind) {
delete_dfa_ = DeleteDFA;
// Synchronize with "quick check" above.
- ANNOTATE_HAPPENS_BEFORE(dfa);
- WriteMemoryBarrier();
- *pdfa = dfa;
+ ATOMIC_STORE_RELEASE(pdfa, dfa);
return dfa;
}
@@ -1925,9 +1901,9 @@ bool Prog::SearchDFA(const StringPiece& text, const StringPiece& const_context,
// as the beginning.
if (match0) {
if (reversed_)
- *match0 = StringPiece(ep, text.end() - ep);
+ match0->set(ep, static_cast<int>(text.end() - ep));
else
- *match0 = StringPiece(text.begin(), ep - text.begin());
+ match0->set(text.begin(), static_cast<int>(ep - text.begin()));
}
return true;
}
@@ -1952,7 +1928,7 @@ int DFA::BuildAllStates() {
q.push_back(params.start);
// Flood to expand every state.
- for (int i = 0; i < q.size(); i++) {
+ for (size_t i = 0; i < q.size(); i++) {
State* s = q[i];
for (int c = 0; c < 257; c++) {
State* ns = RunStateOnByteUnlocked(s, c);
@@ -1963,7 +1939,7 @@ int DFA::BuildAllStates() {
}
}
- return q.size();
+ return static_cast<int>(q.size());
}
// Build out all states in DFA for kind. Returns number of states.
@@ -2035,6 +2011,7 @@ bool DFA::PossibleMatchRange(string* min, string* max, int maxlen) {
// Build minimum prefix.
State* s = params.start;
min->clear();
+ MutexLock lock(&mutex_);
for (int i = 0; i < maxlen; i++) {
if (previously_visited_states[s] > kMaxEltRepetitions) {
VLOG(2) << "Hit kMaxEltRepetitions=" << kMaxEltRepetitions
@@ -2044,7 +2021,7 @@ bool DFA::PossibleMatchRange(string* min, string* max, int maxlen) {
previously_visited_states[s]++;
// Stop if min is a match.
- State* ns = RunStateOnByteUnlocked(s, kByteEndText);
+ State* ns = RunStateOnByte(s, kByteEndText);
if (ns == NULL) // DFA out of memory
return false;
if (ns != DeadState && (ns == FullMatchState || ns->IsMatch()))
@@ -2053,13 +2030,13 @@ bool DFA::PossibleMatchRange(string* min, string* max, int maxlen) {
// Try to extend the string with low bytes.
bool extended = false;
for (int j = 0; j < 256; j++) {
- ns = RunStateOnByteUnlocked(s, j);
+ ns = RunStateOnByte(s, j);
if (ns == NULL) // DFA out of memory
return false;
if (ns == FullMatchState ||
(ns > SpecialStateMax && ns->ninst_ > 0)) {
extended = true;
- min->append(1, j);
+ min->append(1, static_cast<char>(j));
s = ns;
break;
}
@@ -2083,13 +2060,13 @@ bool DFA::PossibleMatchRange(string* min, string* max, int maxlen) {
// Try to extend the string with high bytes.
bool extended = false;
for (int j = 255; j >= 0; j--) {
- State* ns = RunStateOnByteUnlocked(s, j);
+ State* ns = RunStateOnByte(s, j);
if (ns == NULL)
return false;
if (ns == FullMatchState ||
(ns > SpecialStateMax && ns->ninst_ > 0)) {
extended = true;
- max->append(1, j);
+ max->append(1, static_cast<char>(j));
s = ns;
break;
}
@@ -2122,11 +2099,12 @@ bool Prog::PossibleMatchRange(string* min, string* max, int maxlen) {
MutexLock l(&dfa_mutex_);
// Have to use dfa_longest_ to get all strings for full matches.
// For example, (a|aa) never matches aa in first-match mode.
- if (dfa_longest_ == NULL) {
- dfa_longest_ = new DFA(this, Prog::kLongestMatch, dfa_mem_/2);
+ dfa = dfa_longest_;
+ if (dfa == NULL) {
+ dfa = new DFA(this, Prog::kLongestMatch, dfa_mem_/2);
+ ATOMIC_STORE_RELEASE(&dfa_longest_, dfa);
delete_dfa_ = DeleteDFA;
}
- dfa = dfa_longest_;
}
return dfa->PossibleMatchRange(min, max, maxlen);
}
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