1 //== PrintfFormatString.cpp - Analysis of printf format strings --*- C++ -*-==//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Handling of format string in printf and friends.  The structure of format
10 // strings for fprintf() are described in C99 7.19.6.1.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "FormatStringParsing.h"
15 #include "clang/AST/FormatString.h"
16 #include "clang/AST/OSLog.h"
17 #include "clang/Basic/TargetInfo.h"
18 #include "llvm/Support/Regex.h"
19 
20 using clang::analyze_format_string::ArgType;
21 using clang::analyze_format_string::FormatStringHandler;
22 using clang::analyze_format_string::LengthModifier;
23 using clang::analyze_format_string::OptionalAmount;
24 using clang::analyze_format_string::ConversionSpecifier;
25 using clang::analyze_printf::PrintfSpecifier;
26 
27 using namespace clang;
28 
29 typedef clang::analyze_format_string::SpecifierResult<PrintfSpecifier>
30         PrintfSpecifierResult;
31 
32 //===----------------------------------------------------------------------===//
33 // Methods for parsing format strings.
34 //===----------------------------------------------------------------------===//
35 
36 using analyze_format_string::ParseNonPositionAmount;
37 
ParsePrecision(FormatStringHandler & H,PrintfSpecifier & FS,const char * Start,const char * & Beg,const char * E,unsigned * argIndex)38 static bool ParsePrecision(FormatStringHandler &H, PrintfSpecifier &FS,
39                            const char *Start, const char *&Beg, const char *E,
40                            unsigned *argIndex) {
41   if (argIndex) {
42     FS.setPrecision(ParseNonPositionAmount(Beg, E, *argIndex));
43   } else {
44     const OptionalAmount Amt = ParsePositionAmount(H, Start, Beg, E,
45                                            analyze_format_string::PrecisionPos);
46     if (Amt.isInvalid())
47       return true;
48     FS.setPrecision(Amt);
49   }
50   return false;
51 }
52 
ParseObjCFlags(FormatStringHandler & H,PrintfSpecifier & FS,const char * FlagBeg,const char * E,bool Warn)53 static bool ParseObjCFlags(FormatStringHandler &H, PrintfSpecifier &FS,
54                            const char *FlagBeg, const char *E, bool Warn) {
55    StringRef Flag(FlagBeg, E - FlagBeg);
56    // Currently there is only one flag.
57    if (Flag == "tt") {
58      FS.setHasObjCTechnicalTerm(FlagBeg);
59      return false;
60    }
61    // Handle either the case of no flag or an invalid flag.
62    if (Warn) {
63      if (Flag == "")
64        H.HandleEmptyObjCModifierFlag(FlagBeg, E  - FlagBeg);
65      else
66        H.HandleInvalidObjCModifierFlag(FlagBeg, E  - FlagBeg);
67    }
68    return true;
69 }
70 
ParsePrintfSpecifier(FormatStringHandler & H,const char * & Beg,const char * E,unsigned & argIndex,const LangOptions & LO,const TargetInfo & Target,bool Warn,bool isFreeBSDKPrintf)71 static PrintfSpecifierResult ParsePrintfSpecifier(FormatStringHandler &H,
72                                                   const char *&Beg,
73                                                   const char *E,
74                                                   unsigned &argIndex,
75                                                   const LangOptions &LO,
76                                                   const TargetInfo &Target,
77                                                   bool Warn,
78                                                   bool isFreeBSDKPrintf) {
79 
80   using namespace clang::analyze_format_string;
81   using namespace clang::analyze_printf;
82 
83   const char *I = Beg;
84   const char *Start = nullptr;
85   UpdateOnReturn <const char*> UpdateBeg(Beg, I);
86 
87   // Look for a '%' character that indicates the start of a format specifier.
88   for ( ; I != E ; ++I) {
89     char c = *I;
90     if (c == '\0') {
91       // Detect spurious null characters, which are likely errors.
92       H.HandleNullChar(I);
93       return true;
94     }
95     if (c == '%') {
96       Start = I++;  // Record the start of the format specifier.
97       break;
98     }
99   }
100 
101   // No format specifier found?
102   if (!Start)
103     return false;
104 
105   if (I == E) {
106     // No more characters left?
107     if (Warn)
108       H.HandleIncompleteSpecifier(Start, E - Start);
109     return true;
110   }
111 
112   PrintfSpecifier FS;
113   if (ParseArgPosition(H, FS, Start, I, E))
114     return true;
115 
116   if (I == E) {
117     // No more characters left?
118     if (Warn)
119       H.HandleIncompleteSpecifier(Start, E - Start);
120     return true;
121   }
122 
123   if (*I == '{') {
124     ++I;
125     unsigned char PrivacyFlags = 0;
126     StringRef MatchedStr;
127 
128     do {
129       StringRef Str(I, E - I);
130       std::string Match = "^[[:space:]]*"
131                           "(private|public|sensitive|mask\\.[^[:space:],}]*)"
132                           "[[:space:]]*(,|})";
133       llvm::Regex R(Match);
134       SmallVector<StringRef, 2> Matches;
135 
136       if (R.match(Str, &Matches)) {
137         MatchedStr = Matches[1];
138         I += Matches[0].size();
139 
140         // Set the privacy flag if the privacy annotation in the
141         // comma-delimited segment is at least as strict as the privacy
142         // annotations in previous comma-delimited segments.
143         if (MatchedStr.startswith("mask")) {
144           StringRef MaskType = MatchedStr.substr(sizeof("mask.") - 1);
145           unsigned Size = MaskType.size();
146           if (Warn && (Size == 0 || Size > 8))
147             H.handleInvalidMaskType(MaskType);
148           FS.setMaskType(MaskType);
149         } else if (MatchedStr.equals("sensitive"))
150           PrivacyFlags = clang::analyze_os_log::OSLogBufferItem::IsSensitive;
151         else if (PrivacyFlags !=
152                  clang::analyze_os_log::OSLogBufferItem::IsSensitive &&
153                  MatchedStr.equals("private"))
154           PrivacyFlags = clang::analyze_os_log::OSLogBufferItem::IsPrivate;
155         else if (PrivacyFlags == 0 && MatchedStr.equals("public"))
156           PrivacyFlags = clang::analyze_os_log::OSLogBufferItem::IsPublic;
157       } else {
158         size_t CommaOrBracePos =
159             Str.find_if([](char c) { return c == ',' || c == '}'; });
160 
161         if (CommaOrBracePos == StringRef::npos) {
162           // Neither a comma nor the closing brace was found.
163           if (Warn)
164             H.HandleIncompleteSpecifier(Start, E - Start);
165           return true;
166         }
167 
168         I += CommaOrBracePos + 1;
169       }
170       // Continue until the closing brace is found.
171     } while (*(I - 1) == ',');
172 
173     // Set the privacy flag.
174     switch (PrivacyFlags) {
175     case 0:
176       break;
177     case clang::analyze_os_log::OSLogBufferItem::IsPrivate:
178       FS.setIsPrivate(MatchedStr.data());
179       break;
180     case clang::analyze_os_log::OSLogBufferItem::IsPublic:
181       FS.setIsPublic(MatchedStr.data());
182       break;
183     case clang::analyze_os_log::OSLogBufferItem::IsSensitive:
184       FS.setIsSensitive(MatchedStr.data());
185       break;
186     default:
187       llvm_unreachable("Unexpected privacy flag value");
188     }
189   }
190 
191   // Look for flags (if any).
192   bool hasMore = true;
193   for ( ; I != E; ++I) {
194     switch (*I) {
195       default: hasMore = false; break;
196       case '\'':
197         // FIXME: POSIX specific.  Always accept?
198         FS.setHasThousandsGrouping(I);
199         break;
200       case '-': FS.setIsLeftJustified(I); break;
201       case '+': FS.setHasPlusPrefix(I); break;
202       case ' ': FS.setHasSpacePrefix(I); break;
203       case '#': FS.setHasAlternativeForm(I); break;
204       case '0': FS.setHasLeadingZeros(I); break;
205     }
206     if (!hasMore)
207       break;
208   }
209 
210   if (I == E) {
211     // No more characters left?
212     if (Warn)
213       H.HandleIncompleteSpecifier(Start, E - Start);
214     return true;
215   }
216 
217   // Look for the field width (if any).
218   if (ParseFieldWidth(H, FS, Start, I, E,
219                       FS.usesPositionalArg() ? nullptr : &argIndex))
220     return true;
221 
222   if (I == E) {
223     // No more characters left?
224     if (Warn)
225       H.HandleIncompleteSpecifier(Start, E - Start);
226     return true;
227   }
228 
229   // Look for the precision (if any).
230   if (*I == '.') {
231     ++I;
232     if (I == E) {
233       if (Warn)
234         H.HandleIncompleteSpecifier(Start, E - Start);
235       return true;
236     }
237 
238     if (ParsePrecision(H, FS, Start, I, E,
239                        FS.usesPositionalArg() ? nullptr : &argIndex))
240       return true;
241 
242     if (I == E) {
243       // No more characters left?
244       if (Warn)
245         H.HandleIncompleteSpecifier(Start, E - Start);
246       return true;
247     }
248   }
249 
250   if (ParseVectorModifier(H, FS, I, E, LO))
251     return true;
252 
253   // Look for the length modifier.
254   if (ParseLengthModifier(FS, I, E, LO) && I == E) {
255     // No more characters left?
256     if (Warn)
257       H.HandleIncompleteSpecifier(Start, E - Start);
258     return true;
259   }
260 
261   // Look for the Objective-C modifier flags, if any.
262   // We parse these here, even if they don't apply to
263   // the conversion specifier, and then emit an error
264   // later if the conversion specifier isn't '@'.  This
265   // enables better recovery, and we don't know if
266   // these flags are applicable until later.
267   const char *ObjCModifierFlagsStart = nullptr,
268              *ObjCModifierFlagsEnd = nullptr;
269   if (*I == '[') {
270     ObjCModifierFlagsStart = I;
271     ++I;
272     auto flagStart = I;
273     for (;; ++I) {
274       ObjCModifierFlagsEnd = I;
275       if (I == E) {
276         if (Warn)
277           H.HandleIncompleteSpecifier(Start, E - Start);
278         return true;
279       }
280       // Did we find the closing ']'?
281       if (*I == ']') {
282         if (ParseObjCFlags(H, FS, flagStart, I, Warn))
283           return true;
284         ++I;
285         break;
286       }
287       // There are no separators defined yet for multiple
288       // Objective-C modifier flags.  When those are
289       // defined, this is the place to check.
290     }
291   }
292 
293   if (*I == '\0') {
294     // Detect spurious null characters, which are likely errors.
295     H.HandleNullChar(I);
296     return true;
297   }
298 
299   // Finally, look for the conversion specifier.
300   const char *conversionPosition = I++;
301   ConversionSpecifier::Kind k = ConversionSpecifier::InvalidSpecifier;
302   switch (*conversionPosition) {
303     default:
304       break;
305     // C99: 7.19.6.1 (section 8).
306     case '%': k = ConversionSpecifier::PercentArg;   break;
307     case 'A': k = ConversionSpecifier::AArg; break;
308     case 'E': k = ConversionSpecifier::EArg; break;
309     case 'F': k = ConversionSpecifier::FArg; break;
310     case 'G': k = ConversionSpecifier::GArg; break;
311     case 'X': k = ConversionSpecifier::XArg; break;
312     case 'a': k = ConversionSpecifier::aArg; break;
313     case 'c': k = ConversionSpecifier::cArg; break;
314     case 'd': k = ConversionSpecifier::dArg; break;
315     case 'e': k = ConversionSpecifier::eArg; break;
316     case 'f': k = ConversionSpecifier::fArg; break;
317     case 'g': k = ConversionSpecifier::gArg; break;
318     case 'i': k = ConversionSpecifier::iArg; break;
319     case 'n':
320       // Not handled, but reserved in OpenCL.
321       if (!LO.OpenCL)
322         k = ConversionSpecifier::nArg;
323       break;
324     case 'o': k = ConversionSpecifier::oArg; break;
325     case 'p': k = ConversionSpecifier::pArg; break;
326     case 's': k = ConversionSpecifier::sArg; break;
327     case 'u': k = ConversionSpecifier::uArg; break;
328     case 'x': k = ConversionSpecifier::xArg; break;
329     // POSIX specific.
330     case 'C': k = ConversionSpecifier::CArg; break;
331     case 'S': k = ConversionSpecifier::SArg; break;
332     // Apple extension for os_log
333     case 'P':
334       k = ConversionSpecifier::PArg;
335       break;
336     // Objective-C.
337     case '@': k = ConversionSpecifier::ObjCObjArg; break;
338     // Glibc specific.
339     case 'm': k = ConversionSpecifier::PrintErrno; break;
340     // FreeBSD kernel specific.
341     case 'b':
342       if (isFreeBSDKPrintf)
343         k = ConversionSpecifier::FreeBSDbArg; // int followed by char *
344       break;
345     case 'r':
346       if (isFreeBSDKPrintf)
347         k = ConversionSpecifier::FreeBSDrArg; // int
348       break;
349     case 'y':
350       if (isFreeBSDKPrintf)
351         k = ConversionSpecifier::FreeBSDyArg; // int
352       break;
353     // Apple-specific.
354     case 'D':
355       if (isFreeBSDKPrintf)
356         k = ConversionSpecifier::FreeBSDDArg; // void * followed by char *
357       else if (Target.getTriple().isOSDarwin())
358         k = ConversionSpecifier::DArg;
359       break;
360     case 'O':
361       if (Target.getTriple().isOSDarwin())
362         k = ConversionSpecifier::OArg;
363       break;
364     case 'U':
365       if (Target.getTriple().isOSDarwin())
366         k = ConversionSpecifier::UArg;
367       break;
368     // MS specific.
369     case 'Z':
370       if (Target.getTriple().isOSMSVCRT())
371         k = ConversionSpecifier::ZArg;
372       break;
373   }
374 
375   // Check to see if we used the Objective-C modifier flags with
376   // a conversion specifier other than '@'.
377   if (k != ConversionSpecifier::ObjCObjArg &&
378       k != ConversionSpecifier::InvalidSpecifier &&
379       ObjCModifierFlagsStart) {
380     H.HandleObjCFlagsWithNonObjCConversion(ObjCModifierFlagsStart,
381                                            ObjCModifierFlagsEnd + 1,
382                                            conversionPosition);
383     return true;
384   }
385 
386   PrintfConversionSpecifier CS(conversionPosition, k);
387   FS.setConversionSpecifier(CS);
388   if (CS.consumesDataArgument() && !FS.usesPositionalArg())
389     FS.setArgIndex(argIndex++);
390   // FreeBSD kernel specific.
391   if (k == ConversionSpecifier::FreeBSDbArg ||
392       k == ConversionSpecifier::FreeBSDDArg)
393     argIndex++;
394 
395   if (k == ConversionSpecifier::InvalidSpecifier) {
396     unsigned Len = I - Start;
397     if (ParseUTF8InvalidSpecifier(Start, E, Len)) {
398       CS.setEndScanList(Start + Len);
399       FS.setConversionSpecifier(CS);
400     }
401     // Assume the conversion takes one argument.
402     return !H.HandleInvalidPrintfConversionSpecifier(FS, Start, Len);
403   }
404   return PrintfSpecifierResult(Start, FS);
405 }
406 
ParsePrintfString(FormatStringHandler & H,const char * I,const char * E,const LangOptions & LO,const TargetInfo & Target,bool isFreeBSDKPrintf)407 bool clang::analyze_format_string::ParsePrintfString(FormatStringHandler &H,
408                                                      const char *I,
409                                                      const char *E,
410                                                      const LangOptions &LO,
411                                                      const TargetInfo &Target,
412                                                      bool isFreeBSDKPrintf) {
413 
414   unsigned argIndex = 0;
415 
416   // Keep looking for a format specifier until we have exhausted the string.
417   while (I != E) {
418     const PrintfSpecifierResult &FSR = ParsePrintfSpecifier(H, I, E, argIndex,
419                                                             LO, Target, true,
420                                                             isFreeBSDKPrintf);
421     // Did a fail-stop error of any kind occur when parsing the specifier?
422     // If so, don't do any more processing.
423     if (FSR.shouldStop())
424       return true;
425     // Did we exhaust the string or encounter an error that
426     // we can recover from?
427     if (!FSR.hasValue())
428       continue;
429     // We have a format specifier.  Pass it to the callback.
430     if (!H.HandlePrintfSpecifier(FSR.getValue(), FSR.getStart(),
431                                  I - FSR.getStart()))
432       return true;
433   }
434   assert(I == E && "Format string not exhausted");
435   return false;
436 }
437 
ParseFormatStringHasSArg(const char * I,const char * E,const LangOptions & LO,const TargetInfo & Target)438 bool clang::analyze_format_string::ParseFormatStringHasSArg(const char *I,
439                                                             const char *E,
440                                                             const LangOptions &LO,
441                                                             const TargetInfo &Target) {
442 
443   unsigned argIndex = 0;
444 
445   // Keep looking for a %s format specifier until we have exhausted the string.
446   FormatStringHandler H;
447   while (I != E) {
448     const PrintfSpecifierResult &FSR = ParsePrintfSpecifier(H, I, E, argIndex,
449                                                             LO, Target, false,
450                                                             false);
451     // Did a fail-stop error of any kind occur when parsing the specifier?
452     // If so, don't do any more processing.
453     if (FSR.shouldStop())
454       return false;
455     // Did we exhaust the string or encounter an error that
456     // we can recover from?
457     if (!FSR.hasValue())
458       continue;
459     const analyze_printf::PrintfSpecifier &FS = FSR.getValue();
460     // Return true if this a %s format specifier.
461     if (FS.getConversionSpecifier().getKind() == ConversionSpecifier::Kind::sArg)
462       return true;
463   }
464   return false;
465 }
466 
parseFormatStringHasFormattingSpecifiers(const char * Begin,const char * End,const LangOptions & LO,const TargetInfo & Target)467 bool clang::analyze_format_string::parseFormatStringHasFormattingSpecifiers(
468     const char *Begin, const char *End, const LangOptions &LO,
469     const TargetInfo &Target) {
470   unsigned ArgIndex = 0;
471   // Keep looking for a formatting specifier until we have exhausted the string.
472   FormatStringHandler H;
473   while (Begin != End) {
474     const PrintfSpecifierResult &FSR =
475         ParsePrintfSpecifier(H, Begin, End, ArgIndex, LO, Target, false, false);
476     if (FSR.shouldStop())
477       break;
478     if (FSR.hasValue())
479       return true;
480   }
481   return false;
482 }
483 
484 //===----------------------------------------------------------------------===//
485 // Methods on PrintfSpecifier.
486 //===----------------------------------------------------------------------===//
487 
getScalarArgType(ASTContext & Ctx,bool IsObjCLiteral) const488 ArgType PrintfSpecifier::getScalarArgType(ASTContext &Ctx,
489                                           bool IsObjCLiteral) const {
490   if (CS.getKind() == ConversionSpecifier::cArg)
491     switch (LM.getKind()) {
492       case LengthModifier::None:
493         return Ctx.IntTy;
494       case LengthModifier::AsLong:
495       case LengthModifier::AsWide:
496         return ArgType(ArgType::WIntTy, "wint_t");
497       case LengthModifier::AsShort:
498         if (Ctx.getTargetInfo().getTriple().isOSMSVCRT())
499           return Ctx.IntTy;
500         LLVM_FALLTHROUGH;
501       default:
502         return ArgType::Invalid();
503     }
504 
505   if (CS.isIntArg())
506     switch (LM.getKind()) {
507       case LengthModifier::AsLongDouble:
508         // GNU extension.
509         return Ctx.LongLongTy;
510       case LengthModifier::None:
511       case LengthModifier::AsShortLong:
512         return Ctx.IntTy;
513       case LengthModifier::AsInt32:
514         return ArgType(Ctx.IntTy, "__int32");
515       case LengthModifier::AsChar:
516         return ArgType::AnyCharTy;
517       case LengthModifier::AsShort: return Ctx.ShortTy;
518       case LengthModifier::AsLong: return Ctx.LongTy;
519       case LengthModifier::AsLongLong:
520       case LengthModifier::AsQuad:
521         return Ctx.LongLongTy;
522       case LengthModifier::AsInt64:
523         return ArgType(Ctx.LongLongTy, "__int64");
524       case LengthModifier::AsIntMax:
525         return ArgType(Ctx.getIntMaxType(), "intmax_t");
526       case LengthModifier::AsSizeT:
527         return ArgType::makeSizeT(ArgType(Ctx.getSignedSizeType(), "ssize_t"));
528       case LengthModifier::AsInt3264:
529         return Ctx.getTargetInfo().getTriple().isArch64Bit()
530                    ? ArgType(Ctx.LongLongTy, "__int64")
531                    : ArgType(Ctx.IntTy, "__int32");
532       case LengthModifier::AsPtrDiff:
533         return ArgType::makePtrdiffT(
534             ArgType(Ctx.getPointerDiffType(), "ptrdiff_t"));
535       case LengthModifier::AsAllocate:
536       case LengthModifier::AsMAllocate:
537       case LengthModifier::AsWide:
538         return ArgType::Invalid();
539     }
540 
541   if (CS.isUIntArg())
542     switch (LM.getKind()) {
543       case LengthModifier::AsLongDouble:
544         // GNU extension.
545         return Ctx.UnsignedLongLongTy;
546       case LengthModifier::None:
547       case LengthModifier::AsShortLong:
548         return Ctx.UnsignedIntTy;
549       case LengthModifier::AsInt32:
550         return ArgType(Ctx.UnsignedIntTy, "unsigned __int32");
551       case LengthModifier::AsChar: return Ctx.UnsignedCharTy;
552       case LengthModifier::AsShort: return Ctx.UnsignedShortTy;
553       case LengthModifier::AsLong: return Ctx.UnsignedLongTy;
554       case LengthModifier::AsLongLong:
555       case LengthModifier::AsQuad:
556         return Ctx.UnsignedLongLongTy;
557       case LengthModifier::AsInt64:
558         return ArgType(Ctx.UnsignedLongLongTy, "unsigned __int64");
559       case LengthModifier::AsIntMax:
560         return ArgType(Ctx.getUIntMaxType(), "uintmax_t");
561       case LengthModifier::AsSizeT:
562         return ArgType::makeSizeT(ArgType(Ctx.getSizeType(), "size_t"));
563       case LengthModifier::AsInt3264:
564         return Ctx.getTargetInfo().getTriple().isArch64Bit()
565                    ? ArgType(Ctx.UnsignedLongLongTy, "unsigned __int64")
566                    : ArgType(Ctx.UnsignedIntTy, "unsigned __int32");
567       case LengthModifier::AsPtrDiff:
568         return ArgType::makePtrdiffT(
569             ArgType(Ctx.getUnsignedPointerDiffType(), "unsigned ptrdiff_t"));
570       case LengthModifier::AsAllocate:
571       case LengthModifier::AsMAllocate:
572       case LengthModifier::AsWide:
573         return ArgType::Invalid();
574     }
575 
576   if (CS.isDoubleArg()) {
577     if (!VectorNumElts.isInvalid()) {
578       switch (LM.getKind()) {
579       case LengthModifier::AsShort:
580         return Ctx.HalfTy;
581       case LengthModifier::AsShortLong:
582         return Ctx.FloatTy;
583       case LengthModifier::AsLong:
584       default:
585         return Ctx.DoubleTy;
586       }
587     }
588 
589     if (LM.getKind() == LengthModifier::AsLongDouble)
590       return Ctx.LongDoubleTy;
591     return Ctx.DoubleTy;
592   }
593 
594   if (CS.getKind() == ConversionSpecifier::nArg) {
595     switch (LM.getKind()) {
596       case LengthModifier::None:
597         return ArgType::PtrTo(Ctx.IntTy);
598       case LengthModifier::AsChar:
599         return ArgType::PtrTo(Ctx.SignedCharTy);
600       case LengthModifier::AsShort:
601         return ArgType::PtrTo(Ctx.ShortTy);
602       case LengthModifier::AsLong:
603         return ArgType::PtrTo(Ctx.LongTy);
604       case LengthModifier::AsLongLong:
605       case LengthModifier::AsQuad:
606         return ArgType::PtrTo(Ctx.LongLongTy);
607       case LengthModifier::AsIntMax:
608         return ArgType::PtrTo(ArgType(Ctx.getIntMaxType(), "intmax_t"));
609       case LengthModifier::AsSizeT:
610         return ArgType::PtrTo(ArgType(Ctx.getSignedSizeType(), "ssize_t"));
611       case LengthModifier::AsPtrDiff:
612         return ArgType::PtrTo(ArgType(Ctx.getPointerDiffType(), "ptrdiff_t"));
613       case LengthModifier::AsLongDouble:
614         return ArgType(); // FIXME: Is this a known extension?
615       case LengthModifier::AsAllocate:
616       case LengthModifier::AsMAllocate:
617       case LengthModifier::AsInt32:
618       case LengthModifier::AsInt3264:
619       case LengthModifier::AsInt64:
620       case LengthModifier::AsWide:
621         return ArgType::Invalid();
622       case LengthModifier::AsShortLong:
623         llvm_unreachable("only used for OpenCL which doesn not handle nArg");
624     }
625   }
626 
627   switch (CS.getKind()) {
628     case ConversionSpecifier::sArg:
629       if (LM.getKind() == LengthModifier::AsWideChar) {
630         if (IsObjCLiteral)
631           return ArgType(Ctx.getPointerType(Ctx.UnsignedShortTy.withConst()),
632                          "const unichar *");
633         return ArgType(ArgType::WCStrTy, "wchar_t *");
634       }
635       if (LM.getKind() == LengthModifier::AsWide)
636         return ArgType(ArgType::WCStrTy, "wchar_t *");
637       return ArgType::CStrTy;
638     case ConversionSpecifier::SArg:
639       if (IsObjCLiteral)
640         return ArgType(Ctx.getPointerType(Ctx.UnsignedShortTy.withConst()),
641                        "const unichar *");
642       if (Ctx.getTargetInfo().getTriple().isOSMSVCRT() &&
643           LM.getKind() == LengthModifier::AsShort)
644         return ArgType::CStrTy;
645       return ArgType(ArgType::WCStrTy, "wchar_t *");
646     case ConversionSpecifier::CArg:
647       if (IsObjCLiteral)
648         return ArgType(Ctx.UnsignedShortTy, "unichar");
649       if (Ctx.getTargetInfo().getTriple().isOSMSVCRT() &&
650           LM.getKind() == LengthModifier::AsShort)
651         return Ctx.IntTy;
652       return ArgType(Ctx.WideCharTy, "wchar_t");
653     case ConversionSpecifier::pArg:
654     case ConversionSpecifier::PArg:
655       return ArgType::CPointerTy;
656     case ConversionSpecifier::ObjCObjArg:
657       return ArgType::ObjCPointerTy;
658     default:
659       break;
660   }
661 
662   // FIXME: Handle other cases.
663   return ArgType();
664 }
665 
666 
getArgType(ASTContext & Ctx,bool IsObjCLiteral) const667 ArgType PrintfSpecifier::getArgType(ASTContext &Ctx,
668                                     bool IsObjCLiteral) const {
669   const PrintfConversionSpecifier &CS = getConversionSpecifier();
670 
671   if (!CS.consumesDataArgument())
672     return ArgType::Invalid();
673 
674   ArgType ScalarTy = getScalarArgType(Ctx, IsObjCLiteral);
675   if (!ScalarTy.isValid() || VectorNumElts.isInvalid())
676     return ScalarTy;
677 
678   return ScalarTy.makeVectorType(Ctx, VectorNumElts.getConstantAmount());
679 }
680 
fixType(QualType QT,const LangOptions & LangOpt,ASTContext & Ctx,bool IsObjCLiteral)681 bool PrintfSpecifier::fixType(QualType QT, const LangOptions &LangOpt,
682                               ASTContext &Ctx, bool IsObjCLiteral) {
683   // %n is different from other conversion specifiers; don't try to fix it.
684   if (CS.getKind() == ConversionSpecifier::nArg)
685     return false;
686 
687   // Handle Objective-C objects first. Note that while the '%@' specifier will
688   // not warn for structure pointer or void pointer arguments (because that's
689   // how CoreFoundation objects are implemented), we only show a fixit for '%@'
690   // if we know it's an object (block, id, class, or __attribute__((NSObject))).
691   if (QT->isObjCRetainableType()) {
692     if (!IsObjCLiteral)
693       return false;
694 
695     CS.setKind(ConversionSpecifier::ObjCObjArg);
696 
697     // Disable irrelevant flags
698     HasThousandsGrouping = false;
699     HasPlusPrefix = false;
700     HasSpacePrefix = false;
701     HasAlternativeForm = false;
702     HasLeadingZeroes = false;
703     Precision.setHowSpecified(OptionalAmount::NotSpecified);
704     LM.setKind(LengthModifier::None);
705 
706     return true;
707   }
708 
709   // Handle strings next (char *, wchar_t *)
710   if (QT->isPointerType() && (QT->getPointeeType()->isAnyCharacterType())) {
711     CS.setKind(ConversionSpecifier::sArg);
712 
713     // Disable irrelevant flags
714     HasAlternativeForm = 0;
715     HasLeadingZeroes = 0;
716 
717     // Set the long length modifier for wide characters
718     if (QT->getPointeeType()->isWideCharType())
719       LM.setKind(LengthModifier::AsWideChar);
720     else
721       LM.setKind(LengthModifier::None);
722 
723     return true;
724   }
725 
726   // If it's an enum, get its underlying type.
727   if (const EnumType *ETy = QT->getAs<EnumType>())
728     QT = ETy->getDecl()->getIntegerType();
729 
730   const BuiltinType *BT = QT->getAs<BuiltinType>();
731   if (!BT) {
732     const VectorType *VT = QT->getAs<VectorType>();
733     if (VT) {
734       QT = VT->getElementType();
735       BT = QT->getAs<BuiltinType>();
736       VectorNumElts = OptionalAmount(VT->getNumElements());
737     }
738   }
739 
740   // We can only work with builtin types.
741   if (!BT)
742     return false;
743 
744   // Set length modifier
745   switch (BT->getKind()) {
746   case BuiltinType::Bool:
747   case BuiltinType::WChar_U:
748   case BuiltinType::WChar_S:
749   case BuiltinType::Char8: // FIXME: Treat like 'char'?
750   case BuiltinType::Char16:
751   case BuiltinType::Char32:
752   case BuiltinType::UInt128:
753   case BuiltinType::Int128:
754   case BuiltinType::Half:
755   case BuiltinType::BFloat16:
756   case BuiltinType::Float16:
757   case BuiltinType::Float128:
758   case BuiltinType::ShortAccum:
759   case BuiltinType::Accum:
760   case BuiltinType::LongAccum:
761   case BuiltinType::UShortAccum:
762   case BuiltinType::UAccum:
763   case BuiltinType::ULongAccum:
764   case BuiltinType::ShortFract:
765   case BuiltinType::Fract:
766   case BuiltinType::LongFract:
767   case BuiltinType::UShortFract:
768   case BuiltinType::UFract:
769   case BuiltinType::ULongFract:
770   case BuiltinType::SatShortAccum:
771   case BuiltinType::SatAccum:
772   case BuiltinType::SatLongAccum:
773   case BuiltinType::SatUShortAccum:
774   case BuiltinType::SatUAccum:
775   case BuiltinType::SatULongAccum:
776   case BuiltinType::SatShortFract:
777   case BuiltinType::SatFract:
778   case BuiltinType::SatLongFract:
779   case BuiltinType::SatUShortFract:
780   case BuiltinType::SatUFract:
781   case BuiltinType::SatULongFract:
782     // Various types which are non-trivial to correct.
783     return false;
784 
785 #define IMAGE_TYPE(ImgType, Id, SingletonId, Access, Suffix) \
786   case BuiltinType::Id:
787 #include "clang/Basic/OpenCLImageTypes.def"
788 #define EXT_OPAQUE_TYPE(ExtType, Id, Ext) \
789   case BuiltinType::Id:
790 #include "clang/Basic/OpenCLExtensionTypes.def"
791 #define SVE_TYPE(Name, Id, SingletonId) \
792   case BuiltinType::Id:
793 #include "clang/Basic/AArch64SVEACLETypes.def"
794 #define PPC_MMA_VECTOR_TYPE(Name, Id, Size) \
795   case BuiltinType::Id:
796 #include "clang/Basic/PPCTypes.def"
797 #define SIGNED_TYPE(Id, SingletonId)
798 #define UNSIGNED_TYPE(Id, SingletonId)
799 #define FLOATING_TYPE(Id, SingletonId)
800 #define BUILTIN_TYPE(Id, SingletonId) \
801   case BuiltinType::Id:
802 #include "clang/AST/BuiltinTypes.def"
803     // Misc other stuff which doesn't make sense here.
804     return false;
805 
806   case BuiltinType::UInt:
807   case BuiltinType::Int:
808   case BuiltinType::Float:
809     LM.setKind(VectorNumElts.isInvalid() ?
810                LengthModifier::None : LengthModifier::AsShortLong);
811     break;
812   case BuiltinType::Double:
813     LM.setKind(VectorNumElts.isInvalid() ?
814                LengthModifier::None : LengthModifier::AsLong);
815     break;
816   case BuiltinType::Char_U:
817   case BuiltinType::UChar:
818   case BuiltinType::Char_S:
819   case BuiltinType::SChar:
820     LM.setKind(LengthModifier::AsChar);
821     break;
822 
823   case BuiltinType::Short:
824   case BuiltinType::UShort:
825     LM.setKind(LengthModifier::AsShort);
826     break;
827 
828   case BuiltinType::Long:
829   case BuiltinType::ULong:
830     LM.setKind(LengthModifier::AsLong);
831     break;
832 
833   case BuiltinType::LongLong:
834   case BuiltinType::ULongLong:
835     LM.setKind(LengthModifier::AsLongLong);
836     break;
837 
838   case BuiltinType::LongDouble:
839     LM.setKind(LengthModifier::AsLongDouble);
840     break;
841   }
842 
843   // Handle size_t, ptrdiff_t, etc. that have dedicated length modifiers in C99.
844   if (isa<TypedefType>(QT) && (LangOpt.C99 || LangOpt.CPlusPlus11))
845     namedTypeToLengthModifier(QT, LM);
846 
847   // If fixing the length modifier was enough, we might be done.
848   if (hasValidLengthModifier(Ctx.getTargetInfo(), LangOpt)) {
849     // If we're going to offer a fix anyway, make sure the sign matches.
850     switch (CS.getKind()) {
851     case ConversionSpecifier::uArg:
852     case ConversionSpecifier::UArg:
853       if (QT->isSignedIntegerType())
854         CS.setKind(clang::analyze_format_string::ConversionSpecifier::dArg);
855       break;
856     case ConversionSpecifier::dArg:
857     case ConversionSpecifier::DArg:
858     case ConversionSpecifier::iArg:
859       if (QT->isUnsignedIntegerType() && !HasPlusPrefix)
860         CS.setKind(clang::analyze_format_string::ConversionSpecifier::uArg);
861       break;
862     default:
863       // Other specifiers do not have signed/unsigned variants.
864       break;
865     }
866 
867     const analyze_printf::ArgType &ATR = getArgType(Ctx, IsObjCLiteral);
868     if (ATR.isValid() && ATR.matchesType(Ctx, QT))
869       return true;
870   }
871 
872   // Set conversion specifier and disable any flags which do not apply to it.
873   // Let typedefs to char fall through to int, as %c is silly for uint8_t.
874   if (!isa<TypedefType>(QT) && QT->isCharType()) {
875     CS.setKind(ConversionSpecifier::cArg);
876     LM.setKind(LengthModifier::None);
877     Precision.setHowSpecified(OptionalAmount::NotSpecified);
878     HasAlternativeForm = 0;
879     HasLeadingZeroes = 0;
880     HasPlusPrefix = 0;
881   }
882   // Test for Floating type first as LongDouble can pass isUnsignedIntegerType
883   else if (QT->isRealFloatingType()) {
884     CS.setKind(ConversionSpecifier::fArg);
885   }
886   else if (QT->isSignedIntegerType()) {
887     CS.setKind(ConversionSpecifier::dArg);
888     HasAlternativeForm = 0;
889   }
890   else if (QT->isUnsignedIntegerType()) {
891     CS.setKind(ConversionSpecifier::uArg);
892     HasAlternativeForm = 0;
893     HasPlusPrefix = 0;
894   } else {
895     llvm_unreachable("Unexpected type");
896   }
897 
898   return true;
899 }
900 
toString(raw_ostream & os) const901 void PrintfSpecifier::toString(raw_ostream &os) const {
902   // Whilst some features have no defined order, we are using the order
903   // appearing in the C99 standard (ISO/IEC 9899:1999 (E) 7.19.6.1)
904   os << "%";
905 
906   // Positional args
907   if (usesPositionalArg()) {
908     os << getPositionalArgIndex() << "$";
909   }
910 
911   // Conversion flags
912   if (IsLeftJustified)    os << "-";
913   if (HasPlusPrefix)      os << "+";
914   if (HasSpacePrefix)     os << " ";
915   if (HasAlternativeForm) os << "#";
916   if (HasLeadingZeroes)   os << "0";
917 
918   // Minimum field width
919   FieldWidth.toString(os);
920   // Precision
921   Precision.toString(os);
922 
923   // Vector modifier
924   if (!VectorNumElts.isInvalid())
925     os << 'v' << VectorNumElts.getConstantAmount();
926 
927   // Length modifier
928   os << LM.toString();
929   // Conversion specifier
930   os << CS.toString();
931 }
932 
hasValidPlusPrefix() const933 bool PrintfSpecifier::hasValidPlusPrefix() const {
934   if (!HasPlusPrefix)
935     return true;
936 
937   // The plus prefix only makes sense for signed conversions
938   switch (CS.getKind()) {
939   case ConversionSpecifier::dArg:
940   case ConversionSpecifier::DArg:
941   case ConversionSpecifier::iArg:
942   case ConversionSpecifier::fArg:
943   case ConversionSpecifier::FArg:
944   case ConversionSpecifier::eArg:
945   case ConversionSpecifier::EArg:
946   case ConversionSpecifier::gArg:
947   case ConversionSpecifier::GArg:
948   case ConversionSpecifier::aArg:
949   case ConversionSpecifier::AArg:
950   case ConversionSpecifier::FreeBSDrArg:
951   case ConversionSpecifier::FreeBSDyArg:
952     return true;
953 
954   default:
955     return false;
956   }
957 }
958 
hasValidAlternativeForm() const959 bool PrintfSpecifier::hasValidAlternativeForm() const {
960   if (!HasAlternativeForm)
961     return true;
962 
963   // Alternate form flag only valid with the oxXaAeEfFgG conversions
964   switch (CS.getKind()) {
965   case ConversionSpecifier::oArg:
966   case ConversionSpecifier::OArg:
967   case ConversionSpecifier::xArg:
968   case ConversionSpecifier::XArg:
969   case ConversionSpecifier::aArg:
970   case ConversionSpecifier::AArg:
971   case ConversionSpecifier::eArg:
972   case ConversionSpecifier::EArg:
973   case ConversionSpecifier::fArg:
974   case ConversionSpecifier::FArg:
975   case ConversionSpecifier::gArg:
976   case ConversionSpecifier::GArg:
977   case ConversionSpecifier::FreeBSDrArg:
978   case ConversionSpecifier::FreeBSDyArg:
979     return true;
980 
981   default:
982     return false;
983   }
984 }
985 
hasValidLeadingZeros() const986 bool PrintfSpecifier::hasValidLeadingZeros() const {
987   if (!HasLeadingZeroes)
988     return true;
989 
990   // Leading zeroes flag only valid with the diouxXaAeEfFgG conversions
991   switch (CS.getKind()) {
992   case ConversionSpecifier::dArg:
993   case ConversionSpecifier::DArg:
994   case ConversionSpecifier::iArg:
995   case ConversionSpecifier::oArg:
996   case ConversionSpecifier::OArg:
997   case ConversionSpecifier::uArg:
998   case ConversionSpecifier::UArg:
999   case ConversionSpecifier::xArg:
1000   case ConversionSpecifier::XArg:
1001   case ConversionSpecifier::aArg:
1002   case ConversionSpecifier::AArg:
1003   case ConversionSpecifier::eArg:
1004   case ConversionSpecifier::EArg:
1005   case ConversionSpecifier::fArg:
1006   case ConversionSpecifier::FArg:
1007   case ConversionSpecifier::gArg:
1008   case ConversionSpecifier::GArg:
1009   case ConversionSpecifier::FreeBSDrArg:
1010   case ConversionSpecifier::FreeBSDyArg:
1011     return true;
1012 
1013   default:
1014     return false;
1015   }
1016 }
1017 
hasValidSpacePrefix() const1018 bool PrintfSpecifier::hasValidSpacePrefix() const {
1019   if (!HasSpacePrefix)
1020     return true;
1021 
1022   // The space prefix only makes sense for signed conversions
1023   switch (CS.getKind()) {
1024   case ConversionSpecifier::dArg:
1025   case ConversionSpecifier::DArg:
1026   case ConversionSpecifier::iArg:
1027   case ConversionSpecifier::fArg:
1028   case ConversionSpecifier::FArg:
1029   case ConversionSpecifier::eArg:
1030   case ConversionSpecifier::EArg:
1031   case ConversionSpecifier::gArg:
1032   case ConversionSpecifier::GArg:
1033   case ConversionSpecifier::aArg:
1034   case ConversionSpecifier::AArg:
1035   case ConversionSpecifier::FreeBSDrArg:
1036   case ConversionSpecifier::FreeBSDyArg:
1037     return true;
1038 
1039   default:
1040     return false;
1041   }
1042 }
1043 
hasValidLeftJustified() const1044 bool PrintfSpecifier::hasValidLeftJustified() const {
1045   if (!IsLeftJustified)
1046     return true;
1047 
1048   // The left justified flag is valid for all conversions except n
1049   switch (CS.getKind()) {
1050   case ConversionSpecifier::nArg:
1051     return false;
1052 
1053   default:
1054     return true;
1055   }
1056 }
1057 
hasValidThousandsGroupingPrefix() const1058 bool PrintfSpecifier::hasValidThousandsGroupingPrefix() const {
1059   if (!HasThousandsGrouping)
1060     return true;
1061 
1062   switch (CS.getKind()) {
1063     case ConversionSpecifier::dArg:
1064     case ConversionSpecifier::DArg:
1065     case ConversionSpecifier::iArg:
1066     case ConversionSpecifier::uArg:
1067     case ConversionSpecifier::UArg:
1068     case ConversionSpecifier::fArg:
1069     case ConversionSpecifier::FArg:
1070     case ConversionSpecifier::gArg:
1071     case ConversionSpecifier::GArg:
1072       return true;
1073     default:
1074       return false;
1075   }
1076 }
1077 
hasValidPrecision() const1078 bool PrintfSpecifier::hasValidPrecision() const {
1079   if (Precision.getHowSpecified() == OptionalAmount::NotSpecified)
1080     return true;
1081 
1082   // Precision is only valid with the diouxXaAeEfFgGsP conversions
1083   switch (CS.getKind()) {
1084   case ConversionSpecifier::dArg:
1085   case ConversionSpecifier::DArg:
1086   case ConversionSpecifier::iArg:
1087   case ConversionSpecifier::oArg:
1088   case ConversionSpecifier::OArg:
1089   case ConversionSpecifier::uArg:
1090   case ConversionSpecifier::UArg:
1091   case ConversionSpecifier::xArg:
1092   case ConversionSpecifier::XArg:
1093   case ConversionSpecifier::aArg:
1094   case ConversionSpecifier::AArg:
1095   case ConversionSpecifier::eArg:
1096   case ConversionSpecifier::EArg:
1097   case ConversionSpecifier::fArg:
1098   case ConversionSpecifier::FArg:
1099   case ConversionSpecifier::gArg:
1100   case ConversionSpecifier::GArg:
1101   case ConversionSpecifier::sArg:
1102   case ConversionSpecifier::FreeBSDrArg:
1103   case ConversionSpecifier::FreeBSDyArg:
1104   case ConversionSpecifier::PArg:
1105     return true;
1106 
1107   default:
1108     return false;
1109   }
1110 }
hasValidFieldWidth() const1111 bool PrintfSpecifier::hasValidFieldWidth() const {
1112   if (FieldWidth.getHowSpecified() == OptionalAmount::NotSpecified)
1113       return true;
1114 
1115   // The field width is valid for all conversions except n
1116   switch (CS.getKind()) {
1117   case ConversionSpecifier::nArg:
1118     return false;
1119 
1120   default:
1121     return true;
1122   }
1123 }
1124