Compute first_byte using the Regexp, not the Prog.
Change-Id: Ic893767c752afee4f41d8d39805351cf91c883e7
Reviewed-on: https://code-review.googlesource.com/c/re2/+/56214
Reviewed-by: Paul Wankadia <junyer@google.com>
diff --git a/re2/compile.cc b/re2/compile.cc
index b3e5bdc..2f64a80 100644
--- a/re2/compile.cc
+++ b/re2/compile.cc
@@ -225,8 +225,8 @@
// Single rune.
Frag Literal(Rune r, bool foldcase);
- void Setup(Regexp::ParseFlags, int64_t, RE2::Anchor);
- Prog* Finish();
+ void Setup(Regexp::ParseFlags flags, int64_t max_mem, RE2::Anchor anchor);
+ Prog* Finish(Regexp* re);
// Returns .* where dot = any byte
Frag DotStar();
@@ -1167,10 +1167,10 @@
c.prog_->set_start_unanchored(all.begin);
// Hand ownership of prog_ to caller.
- return c.Finish();
+ return c.Finish(re);
}
-Prog* Compiler::Finish() {
+Prog* Compiler::Finish(Regexp* re) {
if (failed_)
return NULL;
@@ -1186,7 +1186,13 @@
prog_->Optimize();
prog_->Flatten();
prog_->ComputeByteMap();
- prog_->ComputeFirstByte();
+
+ // Compute first byte.
+ std::string prefix;
+ bool prefix_foldcase;
+ if (re->RequiredPrefixUnanchored(&prefix, &prefix_foldcase) &&
+ !prefix_foldcase)
+ prog_->set_first_byte(prefix[0]);
// Record remaining memory for DFA.
if (max_mem_ <= 0) {
@@ -1244,7 +1250,7 @@
c.prog_->set_start(all.begin);
c.prog_->set_start_unanchored(all.begin);
- Prog* prog = c.Finish();
+ Prog* prog = c.Finish(re);
if (prog == NULL)
return NULL;
diff --git a/re2/nfa.cc b/re2/nfa.cc
index 75ca306..720f3e0 100644
--- a/re2/nfa.cc
+++ b/re2/nfa.cc
@@ -629,67 +629,6 @@
return false;
}
-void Prog::ComputeFirstByte() {
- SparseSet q(size());
- q.insert(start());
- for (SparseSet::iterator it = q.begin(); it != q.end(); ++it) {
- int id = *it;
- Prog::Inst* ip = inst(id);
- switch (ip->opcode()) {
- default:
- LOG(DFATAL) << "unhandled " << ip->opcode() << " in ComputeFirstByte";
- break;
-
- case kInstMatch:
- // The empty string matches: no first byte.
- first_byte_ = -1;
- return;
-
- case kInstByteRange:
- if (!ip->last())
- q.insert(id+1);
-
- // Must match only a single byte.
- if (ip->lo() != ip->hi() ||
- (ip->foldcase() && 'a' <= ip->lo() && ip->lo() <= 'z')) {
- first_byte_ = -1;
- return;
- }
- // If we haven't seen any bytes yet, record it;
- // otherwise must match the one we saw before.
- if (first_byte_ == -1) {
- first_byte_ = ip->lo();
- } else if (first_byte_ != ip->lo()) {
- first_byte_ = -1;
- return;
- }
- break;
-
- case kInstNop:
- case kInstCapture:
- case kInstEmptyWidth:
- if (!ip->last())
- q.insert(id+1);
-
- // Continue on.
- // Ignore ip->empty() flags for kInstEmptyWidth
- // in order to be as conservative as possible
- // (assume all possible empty-width flags are true).
- if (ip->out())
- q.insert(ip->out());
- break;
-
- case kInstAltMatch:
- DCHECK(!ip->last());
- q.insert(id+1);
- break;
-
- case kInstFail:
- break;
- }
- }
-}
-
bool
Prog::SearchNFA(const StringPiece& text, const StringPiece& context,
Anchor anchor, MatchKind kind,
diff --git a/re2/prog.h b/re2/prog.h
index 4306672..cac107c 100644
--- a/re2/prog.h
+++ b/re2/prog.h
@@ -198,8 +198,8 @@
Inst *inst(int id) { return &inst_[id]; }
int start() { return start_; }
- int start_unanchored() { return start_unanchored_; }
void set_start(int start) { start_ = start; }
+ int start_unanchored() { return start_unanchored_; }
void set_start_unanchored(int start) { start_unanchored_ = start; }
int size() { return size_; }
bool reversed() { return reversed_; }
@@ -207,8 +207,8 @@
int list_count() { return list_count_; }
int inst_count(InstOp op) { return inst_count_[op]; }
uint16_t* list_heads() { return list_heads_.data(); }
- void set_dfa_mem(int64_t dfa_mem) { dfa_mem_ = dfa_mem; }
int64_t dfa_mem() { return dfa_mem_; }
+ void set_dfa_mem(int64_t dfa_mem) { dfa_mem_ = dfa_mem; }
bool anchor_start() { return anchor_start_; }
void set_anchor_start(bool b) { anchor_start_ = b; }
bool anchor_end() { return anchor_end_; }
@@ -216,6 +216,7 @@
int bytemap_range() { return bytemap_range_; }
const uint8_t* bytemap() { return bytemap_; }
int first_byte() { return first_byte_; }
+ void set_first_byte(int first_byte) { first_byte_ = first_byte; }
// Returns string representation of program for debugging.
std::string Dump();
@@ -293,9 +294,6 @@
// Compute bytemap.
void ComputeByteMap();
- // Computes whether all matches must begin with the same first byte.
- void ComputeFirstByte();
-
// Run peep-hole optimizer on program.
void Optimize();
