1 //===- FileCheck.cpp - Check that File's Contents match what is expected --===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // FileCheck does a line-by line check of a file that validates whether it
11 // contains the expected content. This is useful for regression tests etc.
13 // This program exits with an error status of 2 on error, exit status of 0 if
14 // the file matched the expected contents, and exit status of 1 if it did not
15 // contain the expected contents.
17 //===----------------------------------------------------------------------===//
19 #include "llvm/Support/CommandLine.h"
20 #include "llvm/Support/MemoryBuffer.h"
21 #include "llvm/Support/PrettyStackTrace.h"
22 #include "llvm/Support/Regex.h"
23 #include "llvm/Support/SourceMgr.h"
24 #include "llvm/Support/raw_ostream.h"
25 #include "llvm/Support/Signals.h"
26 #include "llvm/ADT/SmallString.h"
27 #include "llvm/ADT/StringMap.h"
31 static cl::opt<std::string>
32 CheckFilename(cl::Positional, cl::desc("<check-file>"), cl::Required);
34 static cl::opt<std::string>
35 InputFilename("input-file", cl::desc("File to check (defaults to stdin)"),
36 cl::init("-"), cl::value_desc("filename"));
38 static cl::opt<std::string>
39 CheckPrefix("check-prefix", cl::init("CHECK"),
40 cl::desc("Prefix to use from check file (defaults to 'CHECK')"));
43 NoCanonicalizeWhiteSpace("strict-whitespace",
44 cl::desc("Do not treat all horizontal whitespace as equivalent"));
46 //===----------------------------------------------------------------------===//
47 // Pattern Handling Code.
48 //===----------------------------------------------------------------------===//
53 /// MatchEOF - When set, this pattern only matches the end of file. This is
54 /// used for trailing CHECK-NOTs.
57 /// FixedStr - If non-empty, this pattern is a fixed string match with the
58 /// specified fixed string.
61 /// RegEx - If non-empty, this is a regex pattern.
64 /// VariableUses - Entries in this vector map to uses of a variable in the
65 /// pattern, e.g. "foo[[bar]]baz". In this case, the RegExStr will contain
66 /// "foobaz" and we'll get an entry in this vector that tells us to insert the
67 /// value of bar at offset 3.
68 std::vector<std::pair<StringRef, unsigned> > VariableUses;
70 /// VariableDefs - Entries in this vector map to definitions of a variable in
71 /// the pattern, e.g. "foo[[bar:.*]]baz". In this case, the RegExStr will
72 /// contain "foo(.*)baz" and VariableDefs will contain the pair "bar",1. The
73 /// index indicates what parenthesized value captures the variable value.
74 std::vector<std::pair<StringRef, unsigned> > VariableDefs;
78 Pattern(bool matchEOF = false) : MatchEOF(matchEOF) { }
80 bool ParsePattern(StringRef PatternStr, SourceMgr &SM);
82 /// Match - Match the pattern string against the input buffer Buffer. This
83 /// returns the position that is matched or npos if there is no match. If
84 /// there is a match, the size of the matched string is returned in MatchLen.
86 /// The VariableTable StringMap provides the current values of filecheck
87 /// variables and is updated if this match defines new values.
88 size_t Match(StringRef Buffer, size_t &MatchLen,
89 StringMap<StringRef> &VariableTable) const;
91 /// PrintFailureInfo - Print additional information about a failure to match
92 /// involving this pattern.
93 void PrintFailureInfo(const SourceMgr &SM, StringRef Buffer,
94 const StringMap<StringRef> &VariableTable) const;
97 static void AddFixedStringToRegEx(StringRef FixedStr, std::string &TheStr);
98 bool AddRegExToRegEx(StringRef RegExStr, unsigned &CurParen, SourceMgr &SM);
100 /// ComputeMatchDistance - Compute an arbitrary estimate for the quality of
101 /// matching this pattern at the start of \arg Buffer; a distance of zero
102 /// should correspond to a perfect match.
103 unsigned ComputeMatchDistance(StringRef Buffer,
104 const StringMap<StringRef> &VariableTable) const;
108 bool Pattern::ParsePattern(StringRef PatternStr, SourceMgr &SM) {
109 PatternLoc = SMLoc::getFromPointer(PatternStr.data());
111 // Ignore trailing whitespace.
112 while (!PatternStr.empty() &&
113 (PatternStr.back() == ' ' || PatternStr.back() == '\t'))
114 PatternStr = PatternStr.substr(0, PatternStr.size()-1);
116 // Check that there is something on the line.
117 if (PatternStr.empty()) {
118 SM.PrintMessage(PatternLoc, "found empty check string with prefix '" +
119 CheckPrefix+":'", "error");
123 // Check to see if this is a fixed string, or if it has regex pieces.
124 if (PatternStr.size() < 2 ||
125 (PatternStr.find("{{") == StringRef::npos &&
126 PatternStr.find("[[") == StringRef::npos)) {
127 FixedStr = PatternStr;
131 // Paren value #0 is for the fully matched string. Any new parenthesized
132 // values add from their.
133 unsigned CurParen = 1;
135 // Otherwise, there is at least one regex piece. Build up the regex pattern
136 // by escaping scary characters in fixed strings, building up one big regex.
137 while (!PatternStr.empty()) {
139 if (PatternStr.size() >= 2 &&
140 PatternStr[0] == '{' && PatternStr[1] == '{') {
142 // Otherwise, this is the start of a regex match. Scan for the }}.
143 size_t End = PatternStr.find("}}");
144 if (End == StringRef::npos) {
145 SM.PrintMessage(SMLoc::getFromPointer(PatternStr.data()),
146 "found start of regex string with no end '}}'", "error");
150 if (AddRegExToRegEx(PatternStr.substr(2, End-2), CurParen, SM))
152 PatternStr = PatternStr.substr(End+2);
156 // Named RegEx matches. These are of two forms: [[foo:.*]] which matches .*
157 // (or some other regex) and assigns it to the FileCheck variable 'foo'. The
158 // second form is [[foo]] which is a reference to foo. The variable name
159 // itself must be of the form "[a-zA-Z_][0-9a-zA-Z_]*", otherwise we reject
160 // it. This is to catch some common errors.
161 if (PatternStr.size() >= 2 &&
162 PatternStr[0] == '[' && PatternStr[1] == '[') {
163 // Verify that it is terminated properly.
164 size_t End = PatternStr.find("]]");
165 if (End == StringRef::npos) {
166 SM.PrintMessage(SMLoc::getFromPointer(PatternStr.data()),
167 "invalid named regex reference, no ]] found", "error");
171 StringRef MatchStr = PatternStr.substr(2, End-2);
172 PatternStr = PatternStr.substr(End+2);
174 // Get the regex name (e.g. "foo").
175 size_t NameEnd = MatchStr.find(':');
176 StringRef Name = MatchStr.substr(0, NameEnd);
179 SM.PrintMessage(SMLoc::getFromPointer(Name.data()),
180 "invalid name in named regex: empty name", "error");
184 // Verify that the name is well formed.
185 for (unsigned i = 0, e = Name.size(); i != e; ++i)
186 if (Name[i] != '_' &&
187 (Name[i] < 'a' || Name[i] > 'z') &&
188 (Name[i] < 'A' || Name[i] > 'Z') &&
189 (Name[i] < '0' || Name[i] > '9')) {
190 SM.PrintMessage(SMLoc::getFromPointer(Name.data()+i),
191 "invalid name in named regex", "error");
195 // Name can't start with a digit.
196 if (isdigit(Name[0])) {
197 SM.PrintMessage(SMLoc::getFromPointer(Name.data()),
198 "invalid name in named regex", "error");
203 if (NameEnd == StringRef::npos) {
204 VariableUses.push_back(std::make_pair(Name, RegExStr.size()));
208 // Handle [[foo:.*]].
209 VariableDefs.push_back(std::make_pair(Name, CurParen));
213 if (AddRegExToRegEx(MatchStr.substr(NameEnd+1), CurParen, SM))
219 // Handle fixed string matches.
220 // Find the end, which is the start of the next regex.
221 size_t FixedMatchEnd = PatternStr.find("{{");
222 FixedMatchEnd = std::min(FixedMatchEnd, PatternStr.find("[["));
223 AddFixedStringToRegEx(PatternStr.substr(0, FixedMatchEnd), RegExStr);
224 PatternStr = PatternStr.substr(FixedMatchEnd);
231 void Pattern::AddFixedStringToRegEx(StringRef FixedStr, std::string &TheStr) {
232 // Add the characters from FixedStr to the regex, escaping as needed. This
233 // avoids "leaning toothpicks" in common patterns.
234 for (unsigned i = 0, e = FixedStr.size(); i != e; ++i) {
235 switch (FixedStr[i]) {
236 // These are the special characters matched in "p_ere_exp".
252 TheStr += FixedStr[i];
258 bool Pattern::AddRegExToRegEx(StringRef RegexStr, unsigned &CurParen,
262 if (!R.isValid(Error)) {
263 SM.PrintMessage(SMLoc::getFromPointer(RegexStr.data()),
264 "invalid regex: " + Error, "error");
268 RegExStr += RegexStr.str();
269 CurParen += R.getNumMatches();
273 /// Match - Match the pattern string against the input buffer Buffer. This
274 /// returns the position that is matched or npos if there is no match. If
275 /// there is a match, the size of the matched string is returned in MatchLen.
276 size_t Pattern::Match(StringRef Buffer, size_t &MatchLen,
277 StringMap<StringRef> &VariableTable) const {
278 // If this is the EOF pattern, match it immediately.
281 return Buffer.size();
284 // If this is a fixed string pattern, just match it now.
285 if (!FixedStr.empty()) {
286 MatchLen = FixedStr.size();
287 return Buffer.find(FixedStr);
292 // If there are variable uses, we need to create a temporary string with the
294 StringRef RegExToMatch = RegExStr;
296 if (!VariableUses.empty()) {
299 unsigned InsertOffset = 0;
300 for (unsigned i = 0, e = VariableUses.size(); i != e; ++i) {
301 StringMap<StringRef>::iterator it =
302 VariableTable.find(VariableUses[i].first);
303 // If the variable is undefined, return an error.
304 if (it == VariableTable.end())
305 return StringRef::npos;
307 // Look up the value and escape it so that we can plop it into the regex.
309 AddFixedStringToRegEx(it->second, Value);
311 // Plop it into the regex at the adjusted offset.
312 TmpStr.insert(TmpStr.begin()+VariableUses[i].second+InsertOffset,
313 Value.begin(), Value.end());
314 InsertOffset += Value.size();
317 // Match the newly constructed regex.
318 RegExToMatch = TmpStr;
322 SmallVector<StringRef, 4> MatchInfo;
323 if (!Regex(RegExToMatch, Regex::Newline).match(Buffer, &MatchInfo))
324 return StringRef::npos;
326 // Successful regex match.
327 assert(!MatchInfo.empty() && "Didn't get any match");
328 StringRef FullMatch = MatchInfo[0];
330 // If this defines any variables, remember their values.
331 for (unsigned i = 0, e = VariableDefs.size(); i != e; ++i) {
332 assert(VariableDefs[i].second < MatchInfo.size() &&
333 "Internal paren error");
334 VariableTable[VariableDefs[i].first] = MatchInfo[VariableDefs[i].second];
337 MatchLen = FullMatch.size();
338 return FullMatch.data()-Buffer.data();
341 unsigned Pattern::ComputeMatchDistance(StringRef Buffer,
342 const StringMap<StringRef> &VariableTable) const {
343 // Just compute the number of matching characters. For regular expressions, we
344 // just compare against the regex itself and hope for the best.
346 // FIXME: One easy improvement here is have the regex lib generate a single
347 // example regular expression which matches, and use that as the example
349 StringRef ExampleString(FixedStr);
350 if (ExampleString.empty())
351 ExampleString = RegExStr;
353 // Only compare up to the first line in the buffer, or the string size.
354 StringRef BufferPrefix = Buffer.substr(0, ExampleString.size());
355 BufferPrefix = BufferPrefix.split('\n').first;
356 return BufferPrefix.edit_distance(ExampleString);
359 void Pattern::PrintFailureInfo(const SourceMgr &SM, StringRef Buffer,
360 const StringMap<StringRef> &VariableTable) const{
361 // If this was a regular expression using variables, print the current
363 if (!VariableUses.empty()) {
364 for (unsigned i = 0, e = VariableUses.size(); i != e; ++i) {
365 StringRef Var = VariableUses[i].first;
366 StringMap<StringRef>::const_iterator it = VariableTable.find(Var);
367 SmallString<256> Msg;
368 raw_svector_ostream OS(Msg);
370 // Check for undefined variable references.
371 if (it == VariableTable.end()) {
372 OS << "uses undefined variable \"";
373 OS.write_escaped(Var) << "\"";;
375 OS << "with variable \"";
376 OS.write_escaped(Var) << "\" equal to \"";
377 OS.write_escaped(it->second) << "\"";
380 SM.PrintMessage(SMLoc::getFromPointer(Buffer.data()), OS.str(), "note",
385 // Attempt to find the closest/best fuzzy match. Usually an error happens
386 // because some string in the output didn't exactly match. In these cases, we
387 // would like to show the user a best guess at what "should have" matched, to
388 // save them having to actually check the input manually.
389 size_t NumLinesForward = 0;
390 size_t Best = StringRef::npos;
391 double BestQuality = 0;
393 // Use an arbitrary 4k limit on how far we will search.
394 for (size_t i = 0, e = std::min(size_t(4096), Buffer.size()); i != e; ++i) {
395 if (Buffer[i] == '\n')
398 // Patterns have leading whitespace stripped, so skip whitespace when
399 // looking for something which looks like a pattern.
400 if (Buffer[i] == ' ' || Buffer[i] == '\t')
403 // Compute the "quality" of this match as an arbitrary combination of the
404 // match distance and the number of lines skipped to get to this match.
405 unsigned Distance = ComputeMatchDistance(Buffer.substr(i), VariableTable);
406 double Quality = Distance + (NumLinesForward / 100.);
408 if (Quality < BestQuality || Best == StringRef::npos) {
410 BestQuality = Quality;
414 // Print the "possible intended match here" line if we found something
415 // reasonable and not equal to what we showed in the "scanning from here"
417 if (Best && Best != StringRef::npos && BestQuality < 50) {
418 SM.PrintMessage(SMLoc::getFromPointer(Buffer.data() + Best),
419 "possible intended match here", "note");
421 // FIXME: If we wanted to be really friendly we would show why the match
422 // failed, as it can be hard to spot simple one character differences.
426 //===----------------------------------------------------------------------===//
428 //===----------------------------------------------------------------------===//
430 /// CheckString - This is a check that we found in the input file.
432 /// Pat - The pattern to match.
435 /// Loc - The location in the match file that the check string was specified.
438 /// IsCheckNext - This is true if this is a CHECK-NEXT: directive (as opposed
439 /// to a CHECK: directive.
442 /// NotStrings - These are all of the strings that are disallowed from
443 /// occurring between this match string and the previous one (or start of
445 std::vector<std::pair<SMLoc, Pattern> > NotStrings;
447 CheckString(const Pattern &P, SMLoc L, bool isCheckNext)
448 : Pat(P), Loc(L), IsCheckNext(isCheckNext) {}
451 /// CanonicalizeInputFile - Remove duplicate horizontal space from the specified
452 /// memory buffer, free it, and return a new one.
453 static MemoryBuffer *CanonicalizeInputFile(MemoryBuffer *MB) {
454 SmallString<128> NewFile;
455 NewFile.reserve(MB->getBufferSize());
457 for (const char *Ptr = MB->getBufferStart(), *End = MB->getBufferEnd();
459 // Eliminate trailing dosish \r.
460 if (Ptr <= End - 2 && Ptr[0] == '\r' && Ptr[1] == '\n') {
464 // If C is not a horizontal whitespace, skip it.
465 if (*Ptr != ' ' && *Ptr != '\t') {
466 NewFile.push_back(*Ptr);
470 // Otherwise, add one space and advance over neighboring space.
471 NewFile.push_back(' ');
472 while (Ptr+1 != End &&
473 (Ptr[1] == ' ' || Ptr[1] == '\t'))
477 // Free the old buffer and return a new one.
479 MemoryBuffer::getMemBufferCopy(NewFile.str(), MB->getBufferIdentifier());
486 /// ReadCheckFile - Read the check file, which specifies the sequence of
487 /// expected strings. The strings are added to the CheckStrings vector.
488 static bool ReadCheckFile(SourceMgr &SM,
489 std::vector<CheckString> &CheckStrings) {
490 // Open the check file, and tell SourceMgr about it.
491 std::string ErrorStr;
493 MemoryBuffer::getFileOrSTDIN(CheckFilename.c_str(), &ErrorStr);
495 errs() << "Could not open check file '" << CheckFilename << "': "
500 // If we want to canonicalize whitespace, strip excess whitespace from the
501 // buffer containing the CHECK lines.
502 if (!NoCanonicalizeWhiteSpace)
503 F = CanonicalizeInputFile(F);
505 SM.AddNewSourceBuffer(F, SMLoc());
507 // Find all instances of CheckPrefix followed by : in the file.
508 StringRef Buffer = F->getBuffer();
510 std::vector<std::pair<SMLoc, Pattern> > NotMatches;
513 // See if Prefix occurs in the memory buffer.
514 Buffer = Buffer.substr(Buffer.find(CheckPrefix));
516 // If we didn't find a match, we're done.
520 const char *CheckPrefixStart = Buffer.data();
522 // When we find a check prefix, keep track of whether we find CHECK: or
524 bool IsCheckNext = false, IsCheckNot = false;
526 // Verify that the : is present after the prefix.
527 if (Buffer[CheckPrefix.size()] == ':') {
528 Buffer = Buffer.substr(CheckPrefix.size()+1);
529 } else if (Buffer.size() > CheckPrefix.size()+6 &&
530 memcmp(Buffer.data()+CheckPrefix.size(), "-NEXT:", 6) == 0) {
531 Buffer = Buffer.substr(CheckPrefix.size()+7);
533 } else if (Buffer.size() > CheckPrefix.size()+5 &&
534 memcmp(Buffer.data()+CheckPrefix.size(), "-NOT:", 5) == 0) {
535 Buffer = Buffer.substr(CheckPrefix.size()+6);
538 Buffer = Buffer.substr(1);
542 // Okay, we found the prefix, yay. Remember the rest of the line, but
543 // ignore leading and trailing whitespace.
544 Buffer = Buffer.substr(Buffer.find_first_not_of(" \t"));
546 // Scan ahead to the end of line.
547 size_t EOL = Buffer.find_first_of("\n\r");
549 // Remember the location of the start of the pattern, for diagnostics.
550 SMLoc PatternLoc = SMLoc::getFromPointer(Buffer.data());
552 // Parse the pattern.
554 if (P.ParsePattern(Buffer.substr(0, EOL), SM))
557 Buffer = Buffer.substr(EOL);
560 // Verify that CHECK-NEXT lines have at least one CHECK line before them.
561 if (IsCheckNext && CheckStrings.empty()) {
562 SM.PrintMessage(SMLoc::getFromPointer(CheckPrefixStart),
563 "found '"+CheckPrefix+"-NEXT:' without previous '"+
564 CheckPrefix+ ": line", "error");
570 NotMatches.push_back(std::make_pair(SMLoc::getFromPointer(Buffer.data()),
576 // Okay, add the string we captured to the output vector and move on.
577 CheckStrings.push_back(CheckString(P,
580 std::swap(NotMatches, CheckStrings.back().NotStrings);
583 // Add an EOF pattern for any trailing CHECK-NOTs.
584 if (!NotMatches.empty()) {
585 CheckStrings.push_back(CheckString(Pattern(true),
586 SMLoc::getFromPointer(Buffer.data()),
588 std::swap(NotMatches, CheckStrings.back().NotStrings);
591 if (CheckStrings.empty()) {
592 errs() << "error: no check strings found with prefix '" << CheckPrefix
600 static void PrintCheckFailed(const SourceMgr &SM, const CheckString &CheckStr,
602 StringMap<StringRef> &VariableTable) {
603 // Otherwise, we have an error, emit an error message.
604 SM.PrintMessage(CheckStr.Loc, "expected string not found in input",
607 // Print the "scanning from here" line. If the current position is at the
608 // end of a line, advance to the start of the next line.
609 Buffer = Buffer.substr(Buffer.find_first_not_of(" \t\n\r"));
611 SM.PrintMessage(SMLoc::getFromPointer(Buffer.data()), "scanning from here",
614 // Allow the pattern to print additional information if desired.
615 CheckStr.Pat.PrintFailureInfo(SM, Buffer, VariableTable);
618 /// CountNumNewlinesBetween - Count the number of newlines in the specified
620 static unsigned CountNumNewlinesBetween(StringRef Range) {
621 unsigned NumNewLines = 0;
624 Range = Range.substr(Range.find_first_of("\n\r"));
625 if (Range.empty()) return NumNewLines;
629 // Handle \n\r and \r\n as a single newline.
630 if (Range.size() > 1 &&
631 (Range[1] == '\n' || Range[1] == '\r') &&
632 (Range[0] != Range[1]))
633 Range = Range.substr(1);
634 Range = Range.substr(1);
638 int main(int argc, char **argv) {
639 sys::PrintStackTraceOnErrorSignal();
640 PrettyStackTraceProgram X(argc, argv);
641 cl::ParseCommandLineOptions(argc, argv);
645 // Read the expected strings from the check file.
646 std::vector<CheckString> CheckStrings;
647 if (ReadCheckFile(SM, CheckStrings))
650 // Open the file to check and add it to SourceMgr.
651 std::string ErrorStr;
653 MemoryBuffer::getFileOrSTDIN(InputFilename.c_str(), &ErrorStr);
655 errs() << "Could not open input file '" << InputFilename << "': "
660 // Remove duplicate spaces in the input file if requested.
661 if (!NoCanonicalizeWhiteSpace)
662 F = CanonicalizeInputFile(F);
664 SM.AddNewSourceBuffer(F, SMLoc());
666 /// VariableTable - This holds all the current filecheck variables.
667 StringMap<StringRef> VariableTable;
669 // Check that we have all of the expected strings, in order, in the input
671 StringRef Buffer = F->getBuffer();
673 const char *LastMatch = Buffer.data();
675 for (unsigned StrNo = 0, e = CheckStrings.size(); StrNo != e; ++StrNo) {
676 const CheckString &CheckStr = CheckStrings[StrNo];
678 StringRef SearchFrom = Buffer;
680 // Find StrNo in the file.
682 size_t MatchPos = CheckStr.Pat.Match(Buffer, MatchLen, VariableTable);
683 Buffer = Buffer.substr(MatchPos);
685 // If we didn't find a match, reject the input.
686 if (MatchPos == StringRef::npos) {
687 PrintCheckFailed(SM, CheckStr, SearchFrom, VariableTable);
691 StringRef SkippedRegion(LastMatch, Buffer.data()-LastMatch);
693 // If this check is a "CHECK-NEXT", verify that the previous match was on
694 // the previous line (i.e. that there is one newline between them).
695 if (CheckStr.IsCheckNext) {
696 // Count the number of newlines between the previous match and this one.
697 assert(LastMatch != F->getBufferStart() &&
698 "CHECK-NEXT can't be the first check in a file");
700 unsigned NumNewLines = CountNumNewlinesBetween(SkippedRegion);
701 if (NumNewLines == 0) {
702 SM.PrintMessage(CheckStr.Loc,
703 CheckPrefix+"-NEXT: is on the same line as previous match",
705 SM.PrintMessage(SMLoc::getFromPointer(Buffer.data()),
706 "'next' match was here", "note");
707 SM.PrintMessage(SMLoc::getFromPointer(LastMatch),
708 "previous match was here", "note");
712 if (NumNewLines != 1) {
713 SM.PrintMessage(CheckStr.Loc,
715 "-NEXT: is not on the line after the previous match",
717 SM.PrintMessage(SMLoc::getFromPointer(Buffer.data()),
718 "'next' match was here", "note");
719 SM.PrintMessage(SMLoc::getFromPointer(LastMatch),
720 "previous match was here", "note");
725 // If this match had "not strings", verify that they don't exist in the
727 for (unsigned ChunkNo = 0, e = CheckStr.NotStrings.size();
728 ChunkNo != e; ++ChunkNo) {
730 size_t Pos = CheckStr.NotStrings[ChunkNo].second.Match(SkippedRegion,
733 if (Pos == StringRef::npos) continue;
735 SM.PrintMessage(SMLoc::getFromPointer(LastMatch+Pos),
736 CheckPrefix+"-NOT: string occurred!", "error");
737 SM.PrintMessage(CheckStr.NotStrings[ChunkNo].first,
738 CheckPrefix+"-NOT: pattern specified here", "note");
743 // Otherwise, everything is good. Step over the matched text and remember
744 // the position after the match as the end of the last match.
745 Buffer = Buffer.substr(MatchLen);
746 LastMatch = Buffer.data();