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Ted Kremenek826a3452010-07-16 02:11:22 +00001// FormatString.cpp - Common stuff for handling printf/scanf formats -*- C++ -*-
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// Shared details for processing format strings of printf and scanf
11// (and friends).
12//
13//===----------------------------------------------------------------------===//
14
15#include "FormatStringParsing.h"
16
17using clang::analyze_format_string::ArgTypeResult;
18using clang::analyze_format_string::FormatStringHandler;
19using clang::analyze_format_string::FormatSpecifier;
20using clang::analyze_format_string::LengthModifier;
21using clang::analyze_format_string::OptionalAmount;
22using clang::analyze_format_string::PositionContext;
Ted Kremeneka412a492010-07-20 20:04:42 +000023using clang::analyze_format_string::ConversionSpecifier;
Ted Kremenek826a3452010-07-16 02:11:22 +000024using namespace clang;
25
26// Key function to FormatStringHandler.
27FormatStringHandler::~FormatStringHandler() {}
28
29//===----------------------------------------------------------------------===//
30// Functions for parsing format strings components in both printf and
31// scanf format strings.
32//===----------------------------------------------------------------------===//
33
34OptionalAmount
35clang::analyze_format_string::ParseAmount(const char *&Beg, const char *E) {
36 const char *I = Beg;
37 UpdateOnReturn <const char*> UpdateBeg(Beg, I);
38
39 unsigned accumulator = 0;
40 bool hasDigits = false;
41
42 for ( ; I != E; ++I) {
43 char c = *I;
44 if (c >= '0' && c <= '9') {
45 hasDigits = true;
46 accumulator = (accumulator * 10) + (c - '0');
47 continue;
48 }
49
50 if (hasDigits)
51 return OptionalAmount(OptionalAmount::Constant, accumulator, Beg, I - Beg,
52 false);
53
54 break;
55 }
56
57 return OptionalAmount();
58}
59
60OptionalAmount
61clang::analyze_format_string::ParseNonPositionAmount(const char *&Beg,
62 const char *E,
63 unsigned &argIndex) {
64 if (*Beg == '*') {
65 ++Beg;
66 return OptionalAmount(OptionalAmount::Arg, argIndex++, Beg, 0, false);
67 }
68
69 return ParseAmount(Beg, E);
70}
71
72OptionalAmount
73clang::analyze_format_string::ParsePositionAmount(FormatStringHandler &H,
74 const char *Start,
75 const char *&Beg,
76 const char *E,
77 PositionContext p) {
78 if (*Beg == '*') {
79 const char *I = Beg + 1;
80 const OptionalAmount &Amt = ParseAmount(I, E);
81
82 if (Amt.getHowSpecified() == OptionalAmount::NotSpecified) {
83 H.HandleInvalidPosition(Beg, I - Beg, p);
84 return OptionalAmount(false);
85 }
86
87 if (I == E) {
88 // No more characters left?
89 H.HandleIncompleteSpecifier(Start, E - Start);
90 return OptionalAmount(false);
91 }
92
93 assert(Amt.getHowSpecified() == OptionalAmount::Constant);
94
95 if (*I == '$') {
96 // Handle positional arguments
97
98 // Special case: '*0$', since this is an easy mistake.
99 if (Amt.getConstantAmount() == 0) {
100 H.HandleZeroPosition(Beg, I - Beg + 1);
101 return OptionalAmount(false);
102 }
103
104 const char *Tmp = Beg;
105 Beg = ++I;
106
107 return OptionalAmount(OptionalAmount::Arg, Amt.getConstantAmount() - 1,
108 Tmp, 0, true);
109 }
110
111 H.HandleInvalidPosition(Beg, I - Beg, p);
112 return OptionalAmount(false);
113 }
114
115 return ParseAmount(Beg, E);
116}
117
118
119bool
120clang::analyze_format_string::ParseFieldWidth(FormatStringHandler &H,
121 FormatSpecifier &CS,
122 const char *Start,
123 const char *&Beg, const char *E,
124 unsigned *argIndex) {
125 // FIXME: Support negative field widths.
126 if (argIndex) {
127 CS.setFieldWidth(ParseNonPositionAmount(Beg, E, *argIndex));
128 }
129 else {
130 const OptionalAmount Amt =
131 ParsePositionAmount(H, Start, Beg, E,
132 analyze_format_string::FieldWidthPos);
133
134 if (Amt.isInvalid())
135 return true;
136 CS.setFieldWidth(Amt);
137 }
138 return false;
139}
140
141bool
142clang::analyze_format_string::ParseArgPosition(FormatStringHandler &H,
143 FormatSpecifier &FS,
144 const char *Start,
145 const char *&Beg,
146 const char *E) {
147 const char *I = Beg;
148
149 const OptionalAmount &Amt = ParseAmount(I, E);
150
151 if (I == E) {
152 // No more characters left?
153 H.HandleIncompleteSpecifier(Start, E - Start);
154 return true;
155 }
156
157 if (Amt.getHowSpecified() == OptionalAmount::Constant && *(I++) == '$') {
158 // Special case: '%0$', since this is an easy mistake.
159 if (Amt.getConstantAmount() == 0) {
160 H.HandleZeroPosition(Start, I - Start);
161 return true;
162 }
163
164 FS.setArgIndex(Amt.getConstantAmount() - 1);
165 FS.setUsesPositionalArg();
166 // Update the caller's pointer if we decided to consume
167 // these characters.
168 Beg = I;
169 return false;
170 }
171
172 return false;
173}
174
175bool
176clang::analyze_format_string::ParseLengthModifier(FormatSpecifier &FS,
177 const char *&I,
178 const char *E) {
179 LengthModifier::Kind lmKind = LengthModifier::None;
180 const char *lmPosition = I;
181 switch (*I) {
182 default:
183 return false;
184 case 'h':
185 ++I;
186 lmKind = (I != E && *I == 'h') ?
187 ++I, LengthModifier::AsChar : LengthModifier::AsShort;
188 break;
189 case 'l':
190 ++I;
191 lmKind = (I != E && *I == 'l') ?
192 ++I, LengthModifier::AsLongLong : LengthModifier::AsLong;
193 break;
194 case 'j': lmKind = LengthModifier::AsIntMax; ++I; break;
195 case 'z': lmKind = LengthModifier::AsSizeT; ++I; break;
196 case 't': lmKind = LengthModifier::AsPtrDiff; ++I; break;
197 case 'L': lmKind = LengthModifier::AsLongDouble; ++I; break;
198 case 'q': lmKind = LengthModifier::AsLongLong; ++I; break;
199 }
200 LengthModifier lm(lmPosition, lmKind);
201 FS.setLengthModifier(lm);
202 return true;
203}
204
205//===----------------------------------------------------------------------===//
206// Methods on ArgTypeResult.
207//===----------------------------------------------------------------------===//
208
209bool ArgTypeResult::matchesType(ASTContext &C, QualType argTy) const {
210 switch (K) {
211 case InvalidTy:
David Blaikieb219cfc2011-09-23 05:06:16 +0000212 llvm_unreachable("ArgTypeResult must be valid");
Ted Kremenek826a3452010-07-16 02:11:22 +0000213
214 case UnknownTy:
215 return true;
216
217 case SpecificTy: {
218 argTy = C.getCanonicalType(argTy).getUnqualifiedType();
219 if (T == argTy)
220 return true;
Ted Kremenekdc00d812011-07-13 17:35:14 +0000221 // Check for "compatible types".
Ted Kremenek1ad35be2011-07-14 17:05:32 +0000222 if (const BuiltinType *BT = argTy->getAs<BuiltinType>())
Ted Kremenek826a3452010-07-16 02:11:22 +0000223 switch (BT->getKind()) {
224 default:
225 break;
226 case BuiltinType::Char_S:
227 case BuiltinType::SChar:
Ted Kremenek1ad35be2011-07-14 17:05:32 +0000228 return T == C.UnsignedCharTy;
Ted Kremenekdc00d812011-07-13 17:35:14 +0000229 case BuiltinType::Char_U:
Ted Kremenek1ad35be2011-07-14 17:05:32 +0000230 case BuiltinType::UChar:
231 return T == C.SignedCharTy;
Ted Kremenek826a3452010-07-16 02:11:22 +0000232 case BuiltinType::Short:
Ted Kremenek1ad35be2011-07-14 17:05:32 +0000233 return T == C.UnsignedShortTy;
Ted Kremenek826a3452010-07-16 02:11:22 +0000234 case BuiltinType::UShort:
Ted Kremenek1ad35be2011-07-14 17:05:32 +0000235 return T == C.ShortTy;
Ted Kremenek826a3452010-07-16 02:11:22 +0000236 case BuiltinType::Int:
Ted Kremenek1ad35be2011-07-14 17:05:32 +0000237 return T == C.UnsignedIntTy;
Ted Kremenek826a3452010-07-16 02:11:22 +0000238 case BuiltinType::UInt:
Ted Kremenek1ad35be2011-07-14 17:05:32 +0000239 return T == C.IntTy;
Ted Kremenek826a3452010-07-16 02:11:22 +0000240 case BuiltinType::Long:
Ted Kremenek1ad35be2011-07-14 17:05:32 +0000241 return T == C.UnsignedLongTy;
Ted Kremenek826a3452010-07-16 02:11:22 +0000242 case BuiltinType::ULong:
Ted Kremenek1ad35be2011-07-14 17:05:32 +0000243 return T == C.LongTy;
Ted Kremenek826a3452010-07-16 02:11:22 +0000244 case BuiltinType::LongLong:
Ted Kremenek1ad35be2011-07-14 17:05:32 +0000245 return T == C.UnsignedLongLongTy;
Ted Kremenek826a3452010-07-16 02:11:22 +0000246 case BuiltinType::ULongLong:
Ted Kremenek1ad35be2011-07-14 17:05:32 +0000247 return T == C.LongLongTy;
Ted Kremenek826a3452010-07-16 02:11:22 +0000248 }
249 return false;
250 }
251
252 case CStrTy: {
253 const PointerType *PT = argTy->getAs<PointerType>();
254 if (!PT)
255 return false;
256 QualType pointeeTy = PT->getPointeeType();
257 if (const BuiltinType *BT = pointeeTy->getAs<BuiltinType>())
258 switch (BT->getKind()) {
259 case BuiltinType::Void:
260 case BuiltinType::Char_U:
261 case BuiltinType::UChar:
262 case BuiltinType::Char_S:
263 case BuiltinType::SChar:
264 return true;
265 default:
266 break;
267 }
268
269 return false;
270 }
271
272 case WCStrTy: {
273 const PointerType *PT = argTy->getAs<PointerType>();
274 if (!PT)
275 return false;
276 QualType pointeeTy =
277 C.getCanonicalType(PT->getPointeeType()).getUnqualifiedType();
278 return pointeeTy == C.getWCharType();
279 }
Ted Kremenek9325eaf2010-08-24 22:24:51 +0000280
281 case WIntTy: {
282 // Instead of doing a lookup for the definition of 'wint_t' (which
283 // is defined by the system headers) instead see if wchar_t and
284 // the argument type promote to the same type.
285 QualType PromoWChar =
286 C.getWCharType()->isPromotableIntegerType()
287 ? C.getPromotedIntegerType(C.getWCharType()) : C.getWCharType();
288 QualType PromoArg =
289 argTy->isPromotableIntegerType()
290 ? C.getPromotedIntegerType(argTy) : argTy;
291
292 PromoWChar = C.getCanonicalType(PromoWChar).getUnqualifiedType();
293 PromoArg = C.getCanonicalType(PromoArg).getUnqualifiedType();
294
295 return PromoWChar == PromoArg;
296 }
Ted Kremenek826a3452010-07-16 02:11:22 +0000297
298 case CPointerTy:
Anders Carlsson62425992010-11-06 14:58:53 +0000299 return argTy->isPointerType() || argTy->isObjCObjectPointerType() ||
300 argTy->isNullPtrType();
Ted Kremenek826a3452010-07-16 02:11:22 +0000301
302 case ObjCPointerTy:
Daniel Dunbard6a4d182011-06-28 23:33:55 +0000303 return argTy->getAs<ObjCObjectPointerType>() != NULL;
Ted Kremenek826a3452010-07-16 02:11:22 +0000304 }
305
306 // FIXME: Should be unreachable, but Clang is currently emitting
307 // a warning.
308 return false;
309}
310
311QualType ArgTypeResult::getRepresentativeType(ASTContext &C) const {
312 switch (K) {
313 case InvalidTy:
David Blaikieb219cfc2011-09-23 05:06:16 +0000314 llvm_unreachable("No representative type for Invalid ArgTypeResult");
Ted Kremenek826a3452010-07-16 02:11:22 +0000315 case UnknownTy:
316 return QualType();
317 case SpecificTy:
318 return T;
319 case CStrTy:
320 return C.getPointerType(C.CharTy);
321 case WCStrTy:
322 return C.getPointerType(C.getWCharType());
323 case ObjCPointerTy:
324 return C.ObjCBuiltinIdTy;
325 case CPointerTy:
326 return C.VoidPtrTy;
Ted Kremenek9325eaf2010-08-24 22:24:51 +0000327 case WIntTy: {
328 QualType WC = C.getWCharType();
329 return WC->isPromotableIntegerType() ? C.getPromotedIntegerType(WC) : WC;
330 }
Ted Kremenek826a3452010-07-16 02:11:22 +0000331 }
332
333 // FIXME: Should be unreachable, but Clang is currently emitting
334 // a warning.
335 return QualType();
336}
337
338//===----------------------------------------------------------------------===//
339// Methods on OptionalAmount.
340//===----------------------------------------------------------------------===//
341
342ArgTypeResult
343analyze_format_string::OptionalAmount::getArgType(ASTContext &Ctx) const {
344 return Ctx.IntTy;
345}
346
347//===----------------------------------------------------------------------===//
348// Methods on LengthModifier.
349//===----------------------------------------------------------------------===//
350
351const char *
352analyze_format_string::LengthModifier::toString() const {
353 switch (kind) {
354 case AsChar:
355 return "hh";
356 case AsShort:
357 return "h";
358 case AsLong: // or AsWideChar
359 return "l";
360 case AsLongLong:
361 return "ll";
362 case AsIntMax:
363 return "j";
364 case AsSizeT:
365 return "z";
366 case AsPtrDiff:
367 return "t";
368 case AsLongDouble:
369 return "L";
370 case None:
371 return "";
372 }
373 return NULL;
374}
375
376//===----------------------------------------------------------------------===//
377// Methods on OptionalAmount.
378//===----------------------------------------------------------------------===//
379
Chris Lattner5f9e2722011-07-23 10:55:15 +0000380void OptionalAmount::toString(raw_ostream &os) const {
Ted Kremenek826a3452010-07-16 02:11:22 +0000381 switch (hs) {
382 case Invalid:
383 case NotSpecified:
384 return;
385 case Arg:
386 if (UsesDotPrefix)
387 os << ".";
388 if (usesPositionalArg())
389 os << "*" << getPositionalArgIndex() << "$";
390 else
391 os << "*";
392 break;
393 case Constant:
394 if (UsesDotPrefix)
395 os << ".";
396 os << amt;
397 break;
398 }
399}
400
Ted Kremeneka412a492010-07-20 20:04:42 +0000401//===----------------------------------------------------------------------===//
Michael J. Spencer96827eb2010-07-27 04:46:02 +0000402// Methods on ConversionSpecifier.
Ted Kremeneka412a492010-07-20 20:04:42 +0000403//===----------------------------------------------------------------------===//
404
405bool FormatSpecifier::hasValidLengthModifier() const {
406 switch (LM.getKind()) {
407 case LengthModifier::None:
408 return true;
409
410 // Handle most integer flags
411 case LengthModifier::AsChar:
412 case LengthModifier::AsShort:
413 case LengthModifier::AsLongLong:
414 case LengthModifier::AsIntMax:
415 case LengthModifier::AsSizeT:
416 case LengthModifier::AsPtrDiff:
417 switch (CS.getKind()) {
418 case ConversionSpecifier::dArg:
419 case ConversionSpecifier::iArg:
420 case ConversionSpecifier::oArg:
421 case ConversionSpecifier::uArg:
422 case ConversionSpecifier::xArg:
423 case ConversionSpecifier::XArg:
424 case ConversionSpecifier::nArg:
425 return true;
426 default:
427 return false;
428 }
429
430 // Handle 'l' flag
431 case LengthModifier::AsLong:
432 switch (CS.getKind()) {
433 case ConversionSpecifier::dArg:
434 case ConversionSpecifier::iArg:
435 case ConversionSpecifier::oArg:
436 case ConversionSpecifier::uArg:
437 case ConversionSpecifier::xArg:
438 case ConversionSpecifier::XArg:
439 case ConversionSpecifier::aArg:
440 case ConversionSpecifier::AArg:
441 case ConversionSpecifier::fArg:
442 case ConversionSpecifier::FArg:
443 case ConversionSpecifier::eArg:
444 case ConversionSpecifier::EArg:
445 case ConversionSpecifier::gArg:
446 case ConversionSpecifier::GArg:
447 case ConversionSpecifier::nArg:
448 case ConversionSpecifier::cArg:
449 case ConversionSpecifier::sArg:
450 return true;
451 default:
452 return false;
453 }
454
455 case LengthModifier::AsLongDouble:
456 switch (CS.getKind()) {
457 case ConversionSpecifier::aArg:
458 case ConversionSpecifier::AArg:
459 case ConversionSpecifier::fArg:
460 case ConversionSpecifier::FArg:
461 case ConversionSpecifier::eArg:
462 case ConversionSpecifier::EArg:
463 case ConversionSpecifier::gArg:
464 case ConversionSpecifier::GArg:
465 return true;
466 default:
467 return false;
468 }
469 }
470 return false;
471}
472
473