FileCheck.cpp revision 36b56886974eae4f9c5ebc96befd3e7bfe5de338 
1//===- FileCheck.cpp - Check that File's Contents match what is expected --===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
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.
12//
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.
16//
17//===----------------------------------------------------------------------===//
18
19#include "llvm/ADT/SmallString.h"
20#include "llvm/ADT/StringExtras.h"
21#include "llvm/ADT/StringMap.h"
22#include "llvm/ADT/StringSet.h"
23#include "llvm/Support/CommandLine.h"
24#include "llvm/Support/MemoryBuffer.h"
25#include "llvm/Support/PrettyStackTrace.h"
26#include "llvm/Support/Regex.h"
27#include "llvm/Support/Signals.h"
28#include "llvm/Support/SourceMgr.h"
29#include "llvm/Support/raw_ostream.h"
30#include "llvm/Support/system_error.h"
31#include <algorithm>
32#include <cctype>
33#include <map>
34#include <string>
35#include <vector>
36using namespace llvm;
37
38static cl::opt<std::string>
39CheckFilename(cl::Positional, cl::desc("<check-file>"), cl::Required);
40
41static cl::opt<std::string>
42InputFilename("input-file", cl::desc("File to check (defaults to stdin)"),
43              cl::init("-"), cl::value_desc("filename"));
44
45static cl::list<std::string>
46CheckPrefixes("check-prefix",
47              cl::desc("Prefix to use from check file (defaults to 'CHECK')"));
48
49static cl::opt<bool>
50NoCanonicalizeWhiteSpace("strict-whitespace",
51              cl::desc("Do not treat all horizontal whitespace as equivalent"));
52
53typedef cl::list<std::string>::const_iterator prefix_iterator;
54
55//===----------------------------------------------------------------------===//
56// Pattern Handling Code.
57//===----------------------------------------------------------------------===//
58
59namespace Check {
60  enum CheckType {
61    CheckNone = 0,
62    CheckPlain,
63    CheckNext,
64    CheckNot,
65    CheckDAG,
66    CheckLabel,
67
68    /// MatchEOF - When set, this pattern only matches the end of file. This is
69    /// used for trailing CHECK-NOTs.
70    CheckEOF
71  };
72}
73
74class Pattern {
75  SMLoc PatternLoc;
76
77  Check::CheckType CheckTy;
78
79  /// FixedStr - If non-empty, this pattern is a fixed string match with the
80  /// specified fixed string.
81  StringRef FixedStr;
82
83  /// RegEx - If non-empty, this is a regex pattern.
84  std::string RegExStr;
85
86  /// \brief Contains the number of line this pattern is in.
87  unsigned LineNumber;
88
89  /// VariableUses - Entries in this vector map to uses of a variable in the
90  /// pattern, e.g. "foo[[bar]]baz".  In this case, the RegExStr will contain
91  /// "foobaz" and we'll get an entry in this vector that tells us to insert the
92  /// value of bar at offset 3.
93  std::vector<std::pair<StringRef, unsigned> > VariableUses;
94
95  /// VariableDefs - Maps definitions of variables to their parenthesized
96  /// capture numbers.
97  /// E.g. for the pattern "foo[[bar:.*]]baz", VariableDefs will map "bar" to 1.
98  std::map<StringRef, unsigned> VariableDefs;
99
100public:
101
102  Pattern(Check::CheckType Ty)
103    : CheckTy(Ty) { }
104
105  /// getLoc - Return the location in source code.
106  SMLoc getLoc() const { return PatternLoc; }
107
108  /// ParsePattern - Parse the given string into the Pattern. Prefix provides
109  /// which prefix is being matched, SM provides the SourceMgr used for error
110  /// reports, and LineNumber is the line number in the input file from which
111  /// the pattern string was read.  Returns true in case of an error, false
112  /// otherwise.
113  bool ParsePattern(StringRef PatternStr,
114                    StringRef Prefix,
115                    SourceMgr &SM,
116                    unsigned LineNumber);
117
118  /// Match - Match the pattern string against the input buffer Buffer.  This
119  /// returns the position that is matched or npos if there is no match.  If
120  /// there is a match, the size of the matched string is returned in MatchLen.
121  ///
122  /// The VariableTable StringMap provides the current values of filecheck
123  /// variables and is updated if this match defines new values.
124  size_t Match(StringRef Buffer, size_t &MatchLen,
125               StringMap<StringRef> &VariableTable) const;
126
127  /// PrintFailureInfo - Print additional information about a failure to match
128  /// involving this pattern.
129  void PrintFailureInfo(const SourceMgr &SM, StringRef Buffer,
130                        const StringMap<StringRef> &VariableTable) const;
131
132  bool hasVariable() const { return !(VariableUses.empty() &&
133                                      VariableDefs.empty()); }
134
135  Check::CheckType getCheckTy() const { return CheckTy; }
136
137private:
138  bool AddRegExToRegEx(StringRef RS, unsigned &CurParen, SourceMgr &SM);
139  void AddBackrefToRegEx(unsigned BackrefNum);
140
141  /// ComputeMatchDistance - Compute an arbitrary estimate for the quality of
142  /// matching this pattern at the start of \arg Buffer; a distance of zero
143  /// should correspond to a perfect match.
144  unsigned ComputeMatchDistance(StringRef Buffer,
145                               const StringMap<StringRef> &VariableTable) const;
146
147  /// \brief Evaluates expression and stores the result to \p Value.
148  /// \return true on success. false when the expression has invalid syntax.
149  bool EvaluateExpression(StringRef Expr, std::string &Value) const;
150
151  /// \brief Finds the closing sequence of a regex variable usage or
152  /// definition. Str has to point in the beginning of the definition
153  /// (right after the opening sequence).
154  /// \return offset of the closing sequence within Str, or npos if it was not
155  /// found.
156  size_t FindRegexVarEnd(StringRef Str, SourceMgr &SM);
157};
158
159
160bool Pattern::ParsePattern(StringRef PatternStr,
161                           StringRef Prefix,
162                           SourceMgr &SM,
163                           unsigned LineNumber) {
164  this->LineNumber = LineNumber;
165  PatternLoc = SMLoc::getFromPointer(PatternStr.data());
166
167  // Ignore trailing whitespace.
168  while (!PatternStr.empty() &&
169         (PatternStr.back() == ' ' || PatternStr.back() == '\t'))
170    PatternStr = PatternStr.substr(0, PatternStr.size()-1);
171
172  // Check that there is something on the line.
173  if (PatternStr.empty()) {
174    SM.PrintMessage(PatternLoc, SourceMgr::DK_Error,
175                    "found empty check string with prefix '" +
176                    Prefix + ":'");
177    return true;
178  }
179
180  // Check to see if this is a fixed string, or if it has regex pieces.
181  if (PatternStr.size() < 2 ||
182      (PatternStr.find("{{") == StringRef::npos &&
183       PatternStr.find("[[") == StringRef::npos)) {
184    FixedStr = PatternStr;
185    return false;
186  }
187
188  // Paren value #0 is for the fully matched string.  Any new parenthesized
189  // values add from there.
190  unsigned CurParen = 1;
191
192  // Otherwise, there is at least one regex piece.  Build up the regex pattern
193  // by escaping scary characters in fixed strings, building up one big regex.
194  while (!PatternStr.empty()) {
195    // RegEx matches.
196    if (PatternStr.startswith("{{")) {
197      // This is the start of a regex match.  Scan for the }}.
198      size_t End = PatternStr.find("}}");
199      if (End == StringRef::npos) {
200        SM.PrintMessage(SMLoc::getFromPointer(PatternStr.data()),
201                        SourceMgr::DK_Error,
202                        "found start of regex string with no end '}}'");
203        return true;
204      }
205
206      // Enclose {{}} patterns in parens just like [[]] even though we're not
207      // capturing the result for any purpose.  This is required in case the
208      // expression contains an alternation like: CHECK:  abc{{x|z}}def.  We
209      // want this to turn into: "abc(x|z)def" not "abcx|zdef".
210      RegExStr += '(';
211      ++CurParen;
212
213      if (AddRegExToRegEx(PatternStr.substr(2, End-2), CurParen, SM))
214        return true;
215      RegExStr += ')';
216
217      PatternStr = PatternStr.substr(End+2);
218      continue;
219    }
220
221    // Named RegEx matches.  These are of two forms: [[foo:.*]] which matches .*
222    // (or some other regex) and assigns it to the FileCheck variable 'foo'. The
223    // second form is [[foo]] which is a reference to foo.  The variable name
224    // itself must be of the form "[a-zA-Z_][0-9a-zA-Z_]*", otherwise we reject
225    // it.  This is to catch some common errors.
226    if (PatternStr.startswith("[[")) {
227      // Find the closing bracket pair ending the match.  End is going to be an
228      // offset relative to the beginning of the match string.
229      size_t End = FindRegexVarEnd(PatternStr.substr(2), SM);
230
231      if (End == StringRef::npos) {
232        SM.PrintMessage(SMLoc::getFromPointer(PatternStr.data()),
233                        SourceMgr::DK_Error,
234                        "invalid named regex reference, no ]] found");
235        return true;
236      }
237
238      StringRef MatchStr = PatternStr.substr(2, End);
239      PatternStr = PatternStr.substr(End+4);
240
241      // Get the regex name (e.g. "foo").
242      size_t NameEnd = MatchStr.find(':');
243      StringRef Name = MatchStr.substr(0, NameEnd);
244
245      if (Name.empty()) {
246        SM.PrintMessage(SMLoc::getFromPointer(Name.data()), SourceMgr::DK_Error,
247                        "invalid name in named regex: empty name");
248        return true;
249      }
250
251      // Verify that the name/expression is well formed. FileCheck currently
252      // supports @LINE, @LINE+number, @LINE-number expressions. The check here
253      // is relaxed, more strict check is performed in \c EvaluateExpression.
254      bool IsExpression = false;
255      for (unsigned i = 0, e = Name.size(); i != e; ++i) {
256        if (i == 0 && Name[i] == '@') {
257          if (NameEnd != StringRef::npos) {
258            SM.PrintMessage(SMLoc::getFromPointer(Name.data()),
259                            SourceMgr::DK_Error,
260                            "invalid name in named regex definition");
261            return true;
262          }
263          IsExpression = true;
264          continue;
265        }
266        if (Name[i] != '_' && !isalnum(Name[i]) &&
267            (!IsExpression || (Name[i] != '+' && Name[i] != '-'))) {
268          SM.PrintMessage(SMLoc::getFromPointer(Name.data()+i),
269                          SourceMgr::DK_Error, "invalid name in named regex");
270          return true;
271        }
272      }
273
274      // Name can't start with a digit.
275      if (isdigit(static_cast<unsigned char>(Name[0]))) {
276        SM.PrintMessage(SMLoc::getFromPointer(Name.data()), SourceMgr::DK_Error,
277                        "invalid name in named regex");
278        return true;
279      }
280
281      // Handle [[foo]].
282      if (NameEnd == StringRef::npos) {
283        // Handle variables that were defined earlier on the same line by
284        // emitting a backreference.
285        if (VariableDefs.find(Name) != VariableDefs.end()) {
286          unsigned VarParenNum = VariableDefs[Name];
287          if (VarParenNum < 1 || VarParenNum > 9) {
288            SM.PrintMessage(SMLoc::getFromPointer(Name.data()),
289                            SourceMgr::DK_Error,
290                            "Can't back-reference more than 9 variables");
291            return true;
292          }
293          AddBackrefToRegEx(VarParenNum);
294        } else {
295          VariableUses.push_back(std::make_pair(Name, RegExStr.size()));
296        }
297        continue;
298      }
299
300      // Handle [[foo:.*]].
301      VariableDefs[Name] = CurParen;
302      RegExStr += '(';
303      ++CurParen;
304
305      if (AddRegExToRegEx(MatchStr.substr(NameEnd+1), CurParen, SM))
306        return true;
307
308      RegExStr += ')';
309    }
310
311    // Handle fixed string matches.
312    // Find the end, which is the start of the next regex.
313    size_t FixedMatchEnd = PatternStr.find("{{");
314    FixedMatchEnd = std::min(FixedMatchEnd, PatternStr.find("[["));
315    RegExStr += Regex::escape(PatternStr.substr(0, FixedMatchEnd));
316    PatternStr = PatternStr.substr(FixedMatchEnd);
317  }
318
319  return false;
320}
321
322bool Pattern::AddRegExToRegEx(StringRef RS, unsigned &CurParen,
323                              SourceMgr &SM) {
324  Regex R(RS);
325  std::string Error;
326  if (!R.isValid(Error)) {
327    SM.PrintMessage(SMLoc::getFromPointer(RS.data()), SourceMgr::DK_Error,
328                    "invalid regex: " + Error);
329    return true;
330  }
331
332  RegExStr += RS.str();
333  CurParen += R.getNumMatches();
334  return false;
335}
336
337void Pattern::AddBackrefToRegEx(unsigned BackrefNum) {
338  assert(BackrefNum >= 1 && BackrefNum <= 9 && "Invalid backref number");
339  std::string Backref = std::string("\\") +
340                        std::string(1, '0' + BackrefNum);
341  RegExStr += Backref;
342}
343
344bool Pattern::EvaluateExpression(StringRef Expr, std::string &Value) const {
345  // The only supported expression is @LINE([\+-]\d+)?
346  if (!Expr.startswith("@LINE"))
347    return false;
348  Expr = Expr.substr(StringRef("@LINE").size());
349  int Offset = 0;
350  if (!Expr.empty()) {
351    if (Expr[0] == '+')
352      Expr = Expr.substr(1);
353    else if (Expr[0] != '-')
354      return false;
355    if (Expr.getAsInteger(10, Offset))
356      return false;
357  }
358  Value = llvm::itostr(LineNumber + Offset);
359  return true;
360}
361
362/// Match - Match the pattern string against the input buffer Buffer.  This
363/// returns the position that is matched or npos if there is no match.  If
364/// there is a match, the size of the matched string is returned in MatchLen.
365size_t Pattern::Match(StringRef Buffer, size_t &MatchLen,
366                      StringMap<StringRef> &VariableTable) const {
367  // If this is the EOF pattern, match it immediately.
368  if (CheckTy == Check::CheckEOF) {
369    MatchLen = 0;
370    return Buffer.size();
371  }
372
373  // If this is a fixed string pattern, just match it now.
374  if (!FixedStr.empty()) {
375    MatchLen = FixedStr.size();
376    return Buffer.find(FixedStr);
377  }
378
379  // Regex match.
380
381  // If there are variable uses, we need to create a temporary string with the
382  // actual value.
383  StringRef RegExToMatch = RegExStr;
384  std::string TmpStr;
385  if (!VariableUses.empty()) {
386    TmpStr = RegExStr;
387
388    unsigned InsertOffset = 0;
389    for (unsigned i = 0, e = VariableUses.size(); i != e; ++i) {
390      std::string Value;
391
392      if (VariableUses[i].first[0] == '@') {
393        if (!EvaluateExpression(VariableUses[i].first, Value))
394          return StringRef::npos;
395      } else {
396        StringMap<StringRef>::iterator it =
397          VariableTable.find(VariableUses[i].first);
398        // If the variable is undefined, return an error.
399        if (it == VariableTable.end())
400          return StringRef::npos;
401
402        // Look up the value and escape it so that we can put it into the regex.
403        Value += Regex::escape(it->second);
404      }
405
406      // Plop it into the regex at the adjusted offset.
407      TmpStr.insert(TmpStr.begin()+VariableUses[i].second+InsertOffset,
408                    Value.begin(), Value.end());
409      InsertOffset += Value.size();
410    }
411
412    // Match the newly constructed regex.
413    RegExToMatch = TmpStr;
414  }
415
416
417  SmallVector<StringRef, 4> MatchInfo;
418  if (!Regex(RegExToMatch, Regex::Newline).match(Buffer, &MatchInfo))
419    return StringRef::npos;
420
421  // Successful regex match.
422  assert(!MatchInfo.empty() && "Didn't get any match");
423  StringRef FullMatch = MatchInfo[0];
424
425  // If this defines any variables, remember their values.
426  for (std::map<StringRef, unsigned>::const_iterator I = VariableDefs.begin(),
427                                                     E = VariableDefs.end();
428       I != E; ++I) {
429    assert(I->second < MatchInfo.size() && "Internal paren error");
430    VariableTable[I->first] = MatchInfo[I->second];
431  }
432
433  MatchLen = FullMatch.size();
434  return FullMatch.data()-Buffer.data();
435}
436
437unsigned Pattern::ComputeMatchDistance(StringRef Buffer,
438                              const StringMap<StringRef> &VariableTable) const {
439  // Just compute the number of matching characters. For regular expressions, we
440  // just compare against the regex itself and hope for the best.
441  //
442  // FIXME: One easy improvement here is have the regex lib generate a single
443  // example regular expression which matches, and use that as the example
444  // string.
445  StringRef ExampleString(FixedStr);
446  if (ExampleString.empty())
447    ExampleString = RegExStr;
448
449  // Only compare up to the first line in the buffer, or the string size.
450  StringRef BufferPrefix = Buffer.substr(0, ExampleString.size());
451  BufferPrefix = BufferPrefix.split('\n').first;
452  return BufferPrefix.edit_distance(ExampleString);
453}
454
455void Pattern::PrintFailureInfo(const SourceMgr &SM, StringRef Buffer,
456                               const StringMap<StringRef> &VariableTable) const{
457  // If this was a regular expression using variables, print the current
458  // variable values.
459  if (!VariableUses.empty()) {
460    for (unsigned i = 0, e = VariableUses.size(); i != e; ++i) {
461      SmallString<256> Msg;
462      raw_svector_ostream OS(Msg);
463      StringRef Var = VariableUses[i].first;
464      if (Var[0] == '@') {
465        std::string Value;
466        if (EvaluateExpression(Var, Value)) {
467          OS << "with expression \"";
468          OS.write_escaped(Var) << "\" equal to \"";
469          OS.write_escaped(Value) << "\"";
470        } else {
471          OS << "uses incorrect expression \"";
472          OS.write_escaped(Var) << "\"";
473        }
474      } else {
475        StringMap<StringRef>::const_iterator it = VariableTable.find(Var);
476
477        // Check for undefined variable references.
478        if (it == VariableTable.end()) {
479          OS << "uses undefined variable \"";
480          OS.write_escaped(Var) << "\"";
481        } else {
482          OS << "with variable \"";
483          OS.write_escaped(Var) << "\" equal to \"";
484          OS.write_escaped(it->second) << "\"";
485        }
486      }
487
488      SM.PrintMessage(SMLoc::getFromPointer(Buffer.data()), SourceMgr::DK_Note,
489                      OS.str());
490    }
491  }
492
493  // Attempt to find the closest/best fuzzy match.  Usually an error happens
494  // because some string in the output didn't exactly match. In these cases, we
495  // would like to show the user a best guess at what "should have" matched, to
496  // save them having to actually check the input manually.
497  size_t NumLinesForward = 0;
498  size_t Best = StringRef::npos;
499  double BestQuality = 0;
500
501  // Use an arbitrary 4k limit on how far we will search.
502  for (size_t i = 0, e = std::min(size_t(4096), Buffer.size()); i != e; ++i) {
503    if (Buffer[i] == '\n')
504      ++NumLinesForward;
505
506    // Patterns have leading whitespace stripped, so skip whitespace when
507    // looking for something which looks like a pattern.
508    if (Buffer[i] == ' ' || Buffer[i] == '\t')
509      continue;
510
511    // Compute the "quality" of this match as an arbitrary combination of the
512    // match distance and the number of lines skipped to get to this match.
513    unsigned Distance = ComputeMatchDistance(Buffer.substr(i), VariableTable);
514    double Quality = Distance + (NumLinesForward / 100.);
515
516    if (Quality < BestQuality || Best == StringRef::npos) {
517      Best = i;
518      BestQuality = Quality;
519    }
520  }
521
522  // Print the "possible intended match here" line if we found something
523  // reasonable and not equal to what we showed in the "scanning from here"
524  // line.
525  if (Best && Best != StringRef::npos && BestQuality < 50) {
526      SM.PrintMessage(SMLoc::getFromPointer(Buffer.data() + Best),
527                      SourceMgr::DK_Note, "possible intended match here");
528
529    // FIXME: If we wanted to be really friendly we would show why the match
530    // failed, as it can be hard to spot simple one character differences.
531  }
532}
533
534size_t Pattern::FindRegexVarEnd(StringRef Str, SourceMgr &SM) {
535  // Offset keeps track of the current offset within the input Str
536  size_t Offset = 0;
537  // [...] Nesting depth
538  size_t BracketDepth = 0;
539
540  while (!Str.empty()) {
541    if (Str.startswith("]]") && BracketDepth == 0)
542      return Offset;
543    if (Str[0] == '\\') {
544      // Backslash escapes the next char within regexes, so skip them both.
545      Str = Str.substr(2);
546      Offset += 2;
547    } else {
548      switch (Str[0]) {
549        default:
550          break;
551        case '[':
552          BracketDepth++;
553          break;
554        case ']':
555          if (BracketDepth == 0) {
556            SM.PrintMessage(SMLoc::getFromPointer(Str.data()),
557                            SourceMgr::DK_Error,
558                            "missing closing \"]\" for regex variable");
559            exit(1);
560          }
561          BracketDepth--;
562          break;
563      }
564      Str = Str.substr(1);
565      Offset++;
566    }
567  }
568
569  return StringRef::npos;
570}
571
572
573//===----------------------------------------------------------------------===//
574// Check Strings.
575//===----------------------------------------------------------------------===//
576
577/// CheckString - This is a check that we found in the input file.
578struct CheckString {
579  /// Pat - The pattern to match.
580  Pattern Pat;
581
582  /// Prefix - Which prefix name this check matched.
583  StringRef Prefix;
584
585  /// Loc - The location in the match file that the check string was specified.
586  SMLoc Loc;
587
588  /// CheckTy - Specify what kind of check this is. e.g. CHECK-NEXT: directive,
589  /// as opposed to a CHECK: directive.
590  Check::CheckType CheckTy;
591
592  /// DagNotStrings - These are all of the strings that are disallowed from
593  /// occurring between this match string and the previous one (or start of
594  /// file).
595  std::vector<Pattern> DagNotStrings;
596
597
598  CheckString(const Pattern &P,
599              StringRef S,
600              SMLoc L,
601              Check::CheckType Ty)
602    : Pat(P), Prefix(S), Loc(L), CheckTy(Ty) {}
603
604  /// Check - Match check string and its "not strings" and/or "dag strings".
605  size_t Check(const SourceMgr &SM, StringRef Buffer, bool IsLabelScanMode,
606               size_t &MatchLen, StringMap<StringRef> &VariableTable) const;
607
608  /// CheckNext - Verify there is a single line in the given buffer.
609  bool CheckNext(const SourceMgr &SM, StringRef Buffer) const;
610
611  /// CheckNot - Verify there's no "not strings" in the given buffer.
612  bool CheckNot(const SourceMgr &SM, StringRef Buffer,
613                const std::vector<const Pattern *> &NotStrings,
614                StringMap<StringRef> &VariableTable) const;
615
616  /// CheckDag - Match "dag strings" and their mixed "not strings".
617  size_t CheckDag(const SourceMgr &SM, StringRef Buffer,
618                  std::vector<const Pattern *> &NotStrings,
619                  StringMap<StringRef> &VariableTable) const;
620};
621
622/// Canonicalize whitespaces in the input file. Line endings are replaced
623/// with UNIX-style '\n'.
624///
625/// \param PreserveHorizontal Don't squash consecutive horizontal whitespace
626/// characters to a single space.
627static MemoryBuffer *CanonicalizeInputFile(MemoryBuffer *MB,
628                                           bool PreserveHorizontal) {
629  SmallString<128> NewFile;
630  NewFile.reserve(MB->getBufferSize());
631
632  for (const char *Ptr = MB->getBufferStart(), *End = MB->getBufferEnd();
633       Ptr != End; ++Ptr) {
634    // Eliminate trailing dosish \r.
635    if (Ptr <= End - 2 && Ptr[0] == '\r' && Ptr[1] == '\n') {
636      continue;
637    }
638
639    // If current char is not a horizontal whitespace or if horizontal
640    // whitespace canonicalization is disabled, dump it to output as is.
641    if (PreserveHorizontal || (*Ptr != ' ' && *Ptr != '\t')) {
642      NewFile.push_back(*Ptr);
643      continue;
644    }
645
646    // Otherwise, add one space and advance over neighboring space.
647    NewFile.push_back(' ');
648    while (Ptr+1 != End &&
649           (Ptr[1] == ' ' || Ptr[1] == '\t'))
650      ++Ptr;
651  }
652
653  // Free the old buffer and return a new one.
654  MemoryBuffer *MB2 =
655    MemoryBuffer::getMemBufferCopy(NewFile.str(), MB->getBufferIdentifier());
656
657  delete MB;
658  return MB2;
659}
660
661static bool IsPartOfWord(char c) {
662  return (isalnum(c) || c == '-' || c == '_');
663}
664
665// Get the size of the prefix extension.
666static size_t CheckTypeSize(Check::CheckType Ty) {
667  switch (Ty) {
668  case Check::CheckNone:
669    return 0;
670
671  case Check::CheckPlain:
672    return sizeof(":") - 1;
673
674  case Check::CheckNext:
675    return sizeof("-NEXT:") - 1;
676
677  case Check::CheckNot:
678    return sizeof("-NOT:") - 1;
679
680  case Check::CheckDAG:
681    return sizeof("-DAG:") - 1;
682
683  case Check::CheckLabel:
684    return sizeof("-LABEL:") - 1;
685
686  case Check::CheckEOF:
687    llvm_unreachable("Should not be using EOF size");
688  }
689
690  llvm_unreachable("Bad check type");
691}
692
693static Check::CheckType FindCheckType(StringRef Buffer, StringRef Prefix) {
694  char NextChar = Buffer[Prefix.size()];
695
696  // Verify that the : is present after the prefix.
697  if (NextChar == ':')
698    return Check::CheckPlain;
699
700  if (NextChar != '-')
701    return Check::CheckNone;
702
703  StringRef Rest = Buffer.drop_front(Prefix.size() + 1);
704  if (Rest.startswith("NEXT:"))
705    return Check::CheckNext;
706
707  if (Rest.startswith("NOT:"))
708    return Check::CheckNot;
709
710  if (Rest.startswith("DAG:"))
711    return Check::CheckDAG;
712
713  if (Rest.startswith("LABEL:"))
714    return Check::CheckLabel;
715
716  return Check::CheckNone;
717}
718
719// From the given position, find the next character after the word.
720static size_t SkipWord(StringRef Str, size_t Loc) {
721  while (Loc < Str.size() && IsPartOfWord(Str[Loc]))
722    ++Loc;
723  return Loc;
724}
725
726// Try to find the first match in buffer for any prefix. If a valid match is
727// found, return that prefix and set its type and location.  If there are almost
728// matches (e.g. the actual prefix string is found, but is not an actual check
729// string), but no valid match, return an empty string and set the position to
730// resume searching from. If no partial matches are found, return an empty
731// string and the location will be StringRef::npos. If one prefix is a substring
732// of another, the maximal match should be found. e.g. if "A" and "AA" are
733// prefixes then AA-CHECK: should match the second one.
734static StringRef FindFirstCandidateMatch(StringRef &Buffer,
735                                         Check::CheckType &CheckTy,
736                                         size_t &CheckLoc) {
737  StringRef FirstPrefix;
738  size_t FirstLoc = StringRef::npos;
739  size_t SearchLoc = StringRef::npos;
740  Check::CheckType FirstTy = Check::CheckNone;
741
742  CheckTy = Check::CheckNone;
743  CheckLoc = StringRef::npos;
744
745  for (prefix_iterator I = CheckPrefixes.begin(), E = CheckPrefixes.end();
746       I != E; ++I) {
747    StringRef Prefix(*I);
748    size_t PrefixLoc = Buffer.find(Prefix);
749
750    if (PrefixLoc == StringRef::npos)
751      continue;
752
753    // Track where we are searching for invalid prefixes that look almost right.
754    // We need to only advance to the first partial match on the next attempt
755    // since a partial match could be a substring of a later, valid prefix.
756    // Need to skip to the end of the word, otherwise we could end up
757    // matching a prefix in a substring later.
758    if (PrefixLoc < SearchLoc)
759      SearchLoc = SkipWord(Buffer, PrefixLoc);
760
761    // We only want to find the first match to avoid skipping some.
762    if (PrefixLoc > FirstLoc)
763      continue;
764    // If one matching check-prefix is a prefix of another, choose the
765    // longer one.
766    if (PrefixLoc == FirstLoc && Prefix.size() < FirstPrefix.size())
767      continue;
768
769    StringRef Rest = Buffer.drop_front(PrefixLoc);
770    // Make sure we have actually found the prefix, and not a word containing
771    // it. This should also prevent matching the wrong prefix when one is a
772    // substring of another.
773    if (PrefixLoc != 0 && IsPartOfWord(Buffer[PrefixLoc - 1]))
774      FirstTy = Check::CheckNone;
775    else
776      FirstTy = FindCheckType(Rest, Prefix);
777
778    FirstLoc = PrefixLoc;
779    FirstPrefix = Prefix;
780  }
781
782  // If the first prefix is invalid, we should continue the search after it.
783  if (FirstTy == Check::CheckNone) {
784    CheckLoc = SearchLoc;
785    return "";
786  }
787
788  CheckTy = FirstTy;
789  CheckLoc = FirstLoc;
790  return FirstPrefix;
791}
792
793static StringRef FindFirstMatchingPrefix(StringRef &Buffer,
794                                         unsigned &LineNumber,
795                                         Check::CheckType &CheckTy,
796                                         size_t &CheckLoc) {
797  while (!Buffer.empty()) {
798    StringRef Prefix = FindFirstCandidateMatch(Buffer, CheckTy, CheckLoc);
799    // If we found a real match, we are done.
800    if (!Prefix.empty()) {
801      LineNumber += Buffer.substr(0, CheckLoc).count('\n');
802      return Prefix;
803    }
804
805    // We didn't find any almost matches either, we are also done.
806    if (CheckLoc == StringRef::npos)
807      return StringRef();
808
809    LineNumber += Buffer.substr(0, CheckLoc + 1).count('\n');
810
811    // Advance to the last possible match we found and try again.
812    Buffer = Buffer.drop_front(CheckLoc + 1);
813  }
814
815  return StringRef();
816}
817
818/// ReadCheckFile - Read the check file, which specifies the sequence of
819/// expected strings.  The strings are added to the CheckStrings vector.
820/// Returns true in case of an error, false otherwise.
821static bool ReadCheckFile(SourceMgr &SM,
822                          std::vector<CheckString> &CheckStrings) {
823  std::unique_ptr<MemoryBuffer> File;
824  if (error_code ec =
825        MemoryBuffer::getFileOrSTDIN(CheckFilename, File)) {
826    errs() << "Could not open check file '" << CheckFilename << "': "
827           << ec.message() << '\n';
828    return true;
829  }
830
831  // If we want to canonicalize whitespace, strip excess whitespace from the
832  // buffer containing the CHECK lines. Remove DOS style line endings.
833  MemoryBuffer *F =
834    CanonicalizeInputFile(File.release(), NoCanonicalizeWhiteSpace);
835
836  SM.AddNewSourceBuffer(F, SMLoc());
837
838  // Find all instances of CheckPrefix followed by : in the file.
839  StringRef Buffer = F->getBuffer();
840  std::vector<Pattern> DagNotMatches;
841
842  // LineNumber keeps track of the line on which CheckPrefix instances are
843  // found.
844  unsigned LineNumber = 1;
845
846  while (1) {
847    Check::CheckType CheckTy;
848    size_t PrefixLoc;
849
850    // See if a prefix occurs in the memory buffer.
851    StringRef UsedPrefix = FindFirstMatchingPrefix(Buffer,
852                                                   LineNumber,
853                                                   CheckTy,
854                                                   PrefixLoc);
855    if (UsedPrefix.empty())
856      break;
857
858    Buffer = Buffer.drop_front(PrefixLoc);
859
860    // Location to use for error messages.
861    const char *UsedPrefixStart = Buffer.data() + (PrefixLoc == 0 ? 0 : 1);
862
863    // PrefixLoc is to the start of the prefix. Skip to the end.
864    Buffer = Buffer.drop_front(UsedPrefix.size() + CheckTypeSize(CheckTy));
865
866    // Okay, we found the prefix, yay. Remember the rest of the line, but ignore
867    // leading and trailing whitespace.
868    Buffer = Buffer.substr(Buffer.find_first_not_of(" \t"));
869
870    // Scan ahead to the end of line.
871    size_t EOL = Buffer.find_first_of("\n\r");
872
873    // Remember the location of the start of the pattern, for diagnostics.
874    SMLoc PatternLoc = SMLoc::getFromPointer(Buffer.data());
875
876    // Parse the pattern.
877    Pattern P(CheckTy);
878    if (P.ParsePattern(Buffer.substr(0, EOL), UsedPrefix, SM, LineNumber))
879      return true;
880
881    // Verify that CHECK-LABEL lines do not define or use variables
882    if ((CheckTy == Check::CheckLabel) && P.hasVariable()) {
883      SM.PrintMessage(SMLoc::getFromPointer(UsedPrefixStart),
884                      SourceMgr::DK_Error,
885                      "found '" + UsedPrefix + "-LABEL:'"
886                      " with variable definition or use");
887      return true;
888    }
889
890    Buffer = Buffer.substr(EOL);
891
892    // Verify that CHECK-NEXT lines have at least one CHECK line before them.
893    if ((CheckTy == Check::CheckNext) && CheckStrings.empty()) {
894      SM.PrintMessage(SMLoc::getFromPointer(UsedPrefixStart),
895                      SourceMgr::DK_Error,
896                      "found '" + UsedPrefix + "-NEXT:' without previous '"
897                      + UsedPrefix + ": line");
898      return true;
899    }
900
901    // Handle CHECK-DAG/-NOT.
902    if (CheckTy == Check::CheckDAG || CheckTy == Check::CheckNot) {
903      DagNotMatches.push_back(P);
904      continue;
905    }
906
907    // Okay, add the string we captured to the output vector and move on.
908    CheckStrings.push_back(CheckString(P,
909                                       UsedPrefix,
910                                       PatternLoc,
911                                       CheckTy));
912    std::swap(DagNotMatches, CheckStrings.back().DagNotStrings);
913  }
914
915  // Add an EOF pattern for any trailing CHECK-DAG/-NOTs, and use the first
916  // prefix as a filler for the error message.
917  if (!DagNotMatches.empty()) {
918    CheckStrings.push_back(CheckString(Pattern(Check::CheckEOF),
919                                       CheckPrefixes[0],
920                                       SMLoc::getFromPointer(Buffer.data()),
921                                       Check::CheckEOF));
922    std::swap(DagNotMatches, CheckStrings.back().DagNotStrings);
923  }
924
925  if (CheckStrings.empty()) {
926    errs() << "error: no check strings found with prefix"
927           << (CheckPrefixes.size() > 1 ? "es " : " ");
928    for (size_t I = 0, N = CheckPrefixes.size(); I != N; ++I) {
929      StringRef Prefix(CheckPrefixes[I]);
930      errs() << '\'' << Prefix << ":'";
931      if (I != N - 1)
932        errs() << ", ";
933    }
934
935    errs() << '\n';
936    return true;
937  }
938
939  return false;
940}
941
942static void PrintCheckFailed(const SourceMgr &SM, const SMLoc &Loc,
943                             const Pattern &Pat, StringRef Buffer,
944                             StringMap<StringRef> &VariableTable) {
945  // Otherwise, we have an error, emit an error message.
946  SM.PrintMessage(Loc, SourceMgr::DK_Error,
947                  "expected string not found in input");
948
949  // Print the "scanning from here" line.  If the current position is at the
950  // end of a line, advance to the start of the next line.
951  Buffer = Buffer.substr(Buffer.find_first_not_of(" \t\n\r"));
952
953  SM.PrintMessage(SMLoc::getFromPointer(Buffer.data()), SourceMgr::DK_Note,
954                  "scanning from here");
955
956  // Allow the pattern to print additional information if desired.
957  Pat.PrintFailureInfo(SM, Buffer, VariableTable);
958}
959
960static void PrintCheckFailed(const SourceMgr &SM, const CheckString &CheckStr,
961                             StringRef Buffer,
962                             StringMap<StringRef> &VariableTable) {
963  PrintCheckFailed(SM, CheckStr.Loc, CheckStr.Pat, Buffer, VariableTable);
964}
965
966/// CountNumNewlinesBetween - Count the number of newlines in the specified
967/// range.
968static unsigned CountNumNewlinesBetween(StringRef Range) {
969  unsigned NumNewLines = 0;
970  while (1) {
971    // Scan for newline.
972    Range = Range.substr(Range.find_first_of("\n\r"));
973    if (Range.empty()) return NumNewLines;
974
975    ++NumNewLines;
976
977    // Handle \n\r and \r\n as a single newline.
978    if (Range.size() > 1 &&
979        (Range[1] == '\n' || Range[1] == '\r') &&
980        (Range[0] != Range[1]))
981      Range = Range.substr(1);
982    Range = Range.substr(1);
983  }
984}
985
986size_t CheckString::Check(const SourceMgr &SM, StringRef Buffer,
987                          bool IsLabelScanMode, size_t &MatchLen,
988                          StringMap<StringRef> &VariableTable) const {
989  size_t LastPos = 0;
990  std::vector<const Pattern *> NotStrings;
991
992  // IsLabelScanMode is true when we are scanning forward to find CHECK-LABEL
993  // bounds; we have not processed variable definitions within the bounded block
994  // yet so cannot handle any final CHECK-DAG yet; this is handled when going
995  // over the block again (including the last CHECK-LABEL) in normal mode.
996  if (!IsLabelScanMode) {
997    // Match "dag strings" (with mixed "not strings" if any).
998    LastPos = CheckDag(SM, Buffer, NotStrings, VariableTable);
999    if (LastPos == StringRef::npos)
1000      return StringRef::npos;
1001  }
1002
1003  // Match itself from the last position after matching CHECK-DAG.
1004  StringRef MatchBuffer = Buffer.substr(LastPos);
1005  size_t MatchPos = Pat.Match(MatchBuffer, MatchLen, VariableTable);
1006  if (MatchPos == StringRef::npos) {
1007    PrintCheckFailed(SM, *this, MatchBuffer, VariableTable);
1008    return StringRef::npos;
1009  }
1010  MatchPos += LastPos;
1011
1012  // Similar to the above, in "label-scan mode" we can't yet handle CHECK-NEXT
1013  // or CHECK-NOT
1014  if (!IsLabelScanMode) {
1015    StringRef SkippedRegion = Buffer.substr(LastPos, MatchPos);
1016
1017    // If this check is a "CHECK-NEXT", verify that the previous match was on
1018    // the previous line (i.e. that there is one newline between them).
1019    if (CheckNext(SM, SkippedRegion))
1020      return StringRef::npos;
1021
1022    // If this match had "not strings", verify that they don't exist in the
1023    // skipped region.
1024    if (CheckNot(SM, SkippedRegion, NotStrings, VariableTable))
1025      return StringRef::npos;
1026  }
1027
1028  return MatchPos;
1029}
1030
1031bool CheckString::CheckNext(const SourceMgr &SM, StringRef Buffer) const {
1032  if (CheckTy != Check::CheckNext)
1033    return false;
1034
1035  // Count the number of newlines between the previous match and this one.
1036  assert(Buffer.data() !=
1037         SM.getMemoryBuffer(
1038           SM.FindBufferContainingLoc(
1039             SMLoc::getFromPointer(Buffer.data())))->getBufferStart() &&
1040         "CHECK-NEXT can't be the first check in a file");
1041
1042  unsigned NumNewLines = CountNumNewlinesBetween(Buffer);
1043
1044  if (NumNewLines == 0) {
1045    SM.PrintMessage(Loc, SourceMgr::DK_Error, Prefix +
1046                    "-NEXT: is on the same line as previous match");
1047    SM.PrintMessage(SMLoc::getFromPointer(Buffer.end()),
1048                    SourceMgr::DK_Note, "'next' match was here");
1049    SM.PrintMessage(SMLoc::getFromPointer(Buffer.data()), SourceMgr::DK_Note,
1050                    "previous match ended here");
1051    return true;
1052  }
1053
1054  if (NumNewLines != 1) {
1055    SM.PrintMessage(Loc, SourceMgr::DK_Error, Prefix +
1056                    "-NEXT: is not on the line after the previous match");
1057    SM.PrintMessage(SMLoc::getFromPointer(Buffer.end()),
1058                    SourceMgr::DK_Note, "'next' match was here");
1059    SM.PrintMessage(SMLoc::getFromPointer(Buffer.data()), SourceMgr::DK_Note,
1060                    "previous match ended here");
1061    return true;
1062  }
1063
1064  return false;
1065}
1066
1067bool CheckString::CheckNot(const SourceMgr &SM, StringRef Buffer,
1068                           const std::vector<const Pattern *> &NotStrings,
1069                           StringMap<StringRef> &VariableTable) const {
1070  for (unsigned ChunkNo = 0, e = NotStrings.size();
1071       ChunkNo != e; ++ChunkNo) {
1072    const Pattern *Pat = NotStrings[ChunkNo];
1073    assert((Pat->getCheckTy() == Check::CheckNot) && "Expect CHECK-NOT!");
1074
1075    size_t MatchLen = 0;
1076    size_t Pos = Pat->Match(Buffer, MatchLen, VariableTable);
1077
1078    if (Pos == StringRef::npos) continue;
1079
1080    SM.PrintMessage(SMLoc::getFromPointer(Buffer.data()+Pos),
1081                    SourceMgr::DK_Error,
1082                    Prefix + "-NOT: string occurred!");
1083    SM.PrintMessage(Pat->getLoc(), SourceMgr::DK_Note,
1084                    Prefix + "-NOT: pattern specified here");
1085    return true;
1086  }
1087
1088  return false;
1089}
1090
1091size_t CheckString::CheckDag(const SourceMgr &SM, StringRef Buffer,
1092                             std::vector<const Pattern *> &NotStrings,
1093                             StringMap<StringRef> &VariableTable) const {
1094  if (DagNotStrings.empty())
1095    return 0;
1096
1097  size_t LastPos = 0;
1098  size_t StartPos = LastPos;
1099
1100  for (unsigned ChunkNo = 0, e = DagNotStrings.size();
1101       ChunkNo != e; ++ChunkNo) {
1102    const Pattern &Pat = DagNotStrings[ChunkNo];
1103
1104    assert((Pat.getCheckTy() == Check::CheckDAG ||
1105            Pat.getCheckTy() == Check::CheckNot) &&
1106           "Invalid CHECK-DAG or CHECK-NOT!");
1107
1108    if (Pat.getCheckTy() == Check::CheckNot) {
1109      NotStrings.push_back(&Pat);
1110      continue;
1111    }
1112
1113    assert((Pat.getCheckTy() == Check::CheckDAG) && "Expect CHECK-DAG!");
1114
1115    size_t MatchLen = 0, MatchPos;
1116
1117    // CHECK-DAG always matches from the start.
1118    StringRef MatchBuffer = Buffer.substr(StartPos);
1119    MatchPos = Pat.Match(MatchBuffer, MatchLen, VariableTable);
1120    // With a group of CHECK-DAGs, a single mismatching means the match on
1121    // that group of CHECK-DAGs fails immediately.
1122    if (MatchPos == StringRef::npos) {
1123      PrintCheckFailed(SM, Pat.getLoc(), Pat, MatchBuffer, VariableTable);
1124      return StringRef::npos;
1125    }
1126    // Re-calc it as the offset relative to the start of the original string.
1127    MatchPos += StartPos;
1128
1129    if (!NotStrings.empty()) {
1130      if (MatchPos < LastPos) {
1131        // Reordered?
1132        SM.PrintMessage(SMLoc::getFromPointer(Buffer.data() + MatchPos),
1133                        SourceMgr::DK_Error,
1134                        Prefix + "-DAG: found a match of CHECK-DAG"
1135                        " reordering across a CHECK-NOT");
1136        SM.PrintMessage(SMLoc::getFromPointer(Buffer.data() + LastPos),
1137                        SourceMgr::DK_Note,
1138                        Prefix + "-DAG: the farthest match of CHECK-DAG"
1139                        " is found here");
1140        SM.PrintMessage(NotStrings[0]->getLoc(), SourceMgr::DK_Note,
1141                        Prefix + "-NOT: the crossed pattern specified"
1142                        " here");
1143        SM.PrintMessage(Pat.getLoc(), SourceMgr::DK_Note,
1144                        Prefix + "-DAG: the reordered pattern specified"
1145                        " here");
1146        return StringRef::npos;
1147      }
1148      // All subsequent CHECK-DAGs should be matched from the farthest
1149      // position of all precedent CHECK-DAGs (including this one.)
1150      StartPos = LastPos;
1151      // If there's CHECK-NOTs between two CHECK-DAGs or from CHECK to
1152      // CHECK-DAG, verify that there's no 'not' strings occurred in that
1153      // region.
1154      StringRef SkippedRegion = Buffer.substr(LastPos, MatchPos);
1155      if (CheckNot(SM, SkippedRegion, NotStrings, VariableTable))
1156        return StringRef::npos;
1157      // Clear "not strings".
1158      NotStrings.clear();
1159    }
1160
1161    // Update the last position with CHECK-DAG matches.
1162    LastPos = std::max(MatchPos + MatchLen, LastPos);
1163  }
1164
1165  return LastPos;
1166}
1167
1168// A check prefix must contain only alphanumeric, hyphens and underscores.
1169static bool ValidateCheckPrefix(StringRef CheckPrefix) {
1170  Regex Validator("^[a-zA-Z0-9_-]*$");
1171  return Validator.match(CheckPrefix);
1172}
1173
1174static bool ValidateCheckPrefixes() {
1175  StringSet<> PrefixSet;
1176
1177  for (prefix_iterator I = CheckPrefixes.begin(), E = CheckPrefixes.end();
1178       I != E; ++I) {
1179    StringRef Prefix(*I);
1180
1181    if (!PrefixSet.insert(Prefix))
1182      return false;
1183
1184    if (!ValidateCheckPrefix(Prefix))
1185      return false;
1186  }
1187
1188  return true;
1189}
1190
1191// I don't think there's a way to specify an initial value for cl::list,
1192// so if nothing was specified, add the default
1193static void AddCheckPrefixIfNeeded() {
1194  if (CheckPrefixes.empty())
1195    CheckPrefixes.push_back("CHECK");
1196}
1197
1198int main(int argc, char **argv) {
1199  sys::PrintStackTraceOnErrorSignal();
1200  PrettyStackTraceProgram X(argc, argv);
1201  cl::ParseCommandLineOptions(argc, argv);
1202
1203  if (!ValidateCheckPrefixes()) {
1204    errs() << "Supplied check-prefix is invalid! Prefixes must be unique and "
1205              "start with a letter and contain only alphanumeric characters, "
1206              "hyphens and underscores\n";
1207    return 2;
1208  }
1209
1210  AddCheckPrefixIfNeeded();
1211
1212  SourceMgr SM;
1213
1214  // Read the expected strings from the check file.
1215  std::vector<CheckString> CheckStrings;
1216  if (ReadCheckFile(SM, CheckStrings))
1217    return 2;
1218
1219  // Open the file to check and add it to SourceMgr.
1220  std::unique_ptr<MemoryBuffer> File;
1221  if (error_code ec =
1222        MemoryBuffer::getFileOrSTDIN(InputFilename, File)) {
1223    errs() << "Could not open input file '" << InputFilename << "': "
1224           << ec.message() << '\n';
1225    return 2;
1226  }
1227
1228  if (File->getBufferSize() == 0) {
1229    errs() << "FileCheck error: '" << InputFilename << "' is empty.\n";
1230    return 2;
1231  }
1232
1233  // Remove duplicate spaces in the input file if requested.
1234  // Remove DOS style line endings.
1235  MemoryBuffer *F =
1236    CanonicalizeInputFile(File.release(), NoCanonicalizeWhiteSpace);
1237
1238  SM.AddNewSourceBuffer(F, SMLoc());
1239
1240  /// VariableTable - This holds all the current filecheck variables.
1241  StringMap<StringRef> VariableTable;
1242
1243  // Check that we have all of the expected strings, in order, in the input
1244  // file.
1245  StringRef Buffer = F->getBuffer();
1246
1247  bool hasError = false;
1248
1249  unsigned i = 0, j = 0, e = CheckStrings.size();
1250
1251  while (true) {
1252    StringRef CheckRegion;
1253    if (j == e) {
1254      CheckRegion = Buffer;
1255    } else {
1256      const CheckString &CheckLabelStr = CheckStrings[j];
1257      if (CheckLabelStr.CheckTy != Check::CheckLabel) {
1258        ++j;
1259        continue;
1260      }
1261
1262      // Scan to next CHECK-LABEL match, ignoring CHECK-NOT and CHECK-DAG
1263      size_t MatchLabelLen = 0;
1264      size_t MatchLabelPos = CheckLabelStr.Check(SM, Buffer, true,
1265                                                 MatchLabelLen, VariableTable);
1266      if (MatchLabelPos == StringRef::npos) {
1267        hasError = true;
1268        break;
1269      }
1270
1271      CheckRegion = Buffer.substr(0, MatchLabelPos + MatchLabelLen);
1272      Buffer = Buffer.substr(MatchLabelPos + MatchLabelLen);
1273      ++j;
1274    }
1275
1276    for ( ; i != j; ++i) {
1277      const CheckString &CheckStr = CheckStrings[i];
1278
1279      // Check each string within the scanned region, including a second check
1280      // of any final CHECK-LABEL (to verify CHECK-NOT and CHECK-DAG)
1281      size_t MatchLen = 0;
1282      size_t MatchPos = CheckStr.Check(SM, CheckRegion, false, MatchLen,
1283                                       VariableTable);
1284
1285      if (MatchPos == StringRef::npos) {
1286        hasError = true;
1287        i = j;
1288        break;
1289      }
1290
1291      CheckRegion = CheckRegion.substr(MatchPos + MatchLen);
1292    }
1293
1294    if (j == e)
1295      break;
1296  }
1297
1298  return hasError ? 1 : 0;
1299}
1300