1//=-- ExprEngineC.cpp - ExprEngine support for C expressions ----*- 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// This file defines ExprEngine's support for C expressions.
10//
11//===----------------------------------------------------------------------===//
12
13#include "clang/AST/ExprCXX.h"
14#include "clang/AST/DeclCXX.h"
15#include "clang/StaticAnalyzer/Core/CheckerManager.h"
16#include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
17
18using namespace clang;
19using namespace ento;
20using llvm::APSInt;
21
22/// Optionally conjure and return a symbol for offset when processing
23/// an expression \p Expression.
24/// If \p Other is a location, conjure a symbol for \p Symbol
25/// (offset) if it is unknown so that memory arithmetic always
26/// results in an ElementRegion.
27/// \p Count The number of times the current basic block was visited.
28static SVal conjureOffsetSymbolOnLocation(
29 SVal Symbol, SVal Other, Expr* Expression, SValBuilder &svalBuilder,
30 unsigned Count, const LocationContext *LCtx) {
31 QualType Ty = Expression->getType();
32 if (isa<Loc>(Other) && Ty->isIntegralOrEnumerationType() &&
33 Symbol.isUnknown()) {
34 return svalBuilder.conjureSymbolVal(Expression, LCtx, Ty, Count);
35 }
36 return Symbol;
37}
38
39void ExprEngine::VisitBinaryOperator(const BinaryOperator* B,
40 ExplodedNode *Pred,
41 ExplodedNodeSet &Dst) {
42
43 Expr *LHS = B->getLHS()->IgnoreParens();
44 Expr *RHS = B->getRHS()->IgnoreParens();
45
46 // FIXME: Prechecks eventually go in ::Visit().
47 ExplodedNodeSet CheckedSet;
48 ExplodedNodeSet Tmp2;
49 getCheckerManager().runCheckersForPreStmt(CheckedSet, Pred, B, *this);
50
51 // With both the LHS and RHS evaluated, process the operation itself.
52 for (ExplodedNodeSet::iterator it=CheckedSet.begin(), ei=CheckedSet.end();
53 it != ei; ++it) {
54
55 ProgramStateRef state = (*it)->getState();
56 const LocationContext *LCtx = (*it)->getLocationContext();
57 SVal LeftV = state->getSVal(LHS, LCtx);
58 SVal RightV = state->getSVal(RHS, LCtx);
59
60 BinaryOperator::Opcode Op = B->getOpcode();
61
62 if (Op == BO_Assign) {
63 // EXPERIMENTAL: "Conjured" symbols.
64 // FIXME: Handle structs.
65 if (RightV.isUnknown()) {
66 unsigned Count = currBldrCtx->blockCount();
67 RightV = svalBuilder.conjureSymbolVal(nullptr, B->getRHS(), LCtx,
68 Count);
69 }
70 // Simulate the effects of a "store": bind the value of the RHS
71 // to the L-Value represented by the LHS.
72 SVal ExprVal = B->isGLValue() ? LeftV : RightV;
73 evalStore(Tmp2, B, LHS, *it, state->BindExpr(B, LCtx, ExprVal),
74 LeftV, RightV);
75 continue;
76 }
77
78 if (!B->isAssignmentOp()) {
79 StmtNodeBuilder Bldr(*it, Tmp2, *currBldrCtx);
80
81 if (B->isAdditiveOp()) {
82 // TODO: This can be removed after we enable history tracking with
83 // SymSymExpr.
84 unsigned Count = currBldrCtx->blockCount();
85 RightV = conjureOffsetSymbolOnLocation(
86 RightV, LeftV, RHS, svalBuilder, Count, LCtx);
87 LeftV = conjureOffsetSymbolOnLocation(
88 LeftV, RightV, LHS, svalBuilder, Count, LCtx);
89 }
90
91 // Although we don't yet model pointers-to-members, we do need to make
92 // sure that the members of temporaries have a valid 'this' pointer for
93 // other checks.
94 if (B->getOpcode() == BO_PtrMemD)
95 state = createTemporaryRegionIfNeeded(state, LCtx, LHS);
96
97 // Process non-assignments except commas or short-circuited
98 // logical expressions (LAnd and LOr).
99 SVal Result = evalBinOp(state, Op, LeftV, RightV, B->getType());
100 if (!Result.isUnknown()) {
101 state = state->BindExpr(B, LCtx, Result);
102 } else {
103 // If we cannot evaluate the operation escape the operands.
104 state = escapeValues(state, LeftV, PSK_EscapeOther);
105 state = escapeValues(state, RightV, PSK_EscapeOther);
106 }
107
108 Bldr.generateNode(B, *it, state);
109 continue;
110 }
111
112 assert (B->isCompoundAssignmentOp());
113
114 switch (Op) {
115 default:
116 llvm_unreachable("Invalid opcode for compound assignment.");
117 case BO_MulAssign: Op = BO_Mul; break;
118 case BO_DivAssign: Op = BO_Div; break;
119 case BO_RemAssign: Op = BO_Rem; break;
120 case BO_AddAssign: Op = BO_Add; break;
121 case BO_SubAssign: Op = BO_Sub; break;
122 case BO_ShlAssign: Op = BO_Shl; break;
123 case BO_ShrAssign: Op = BO_Shr; break;
124 case BO_AndAssign: Op = BO_And; break;
125 case BO_XorAssign: Op = BO_Xor; break;
126 case BO_OrAssign: Op = BO_Or; break;
127 }
128
129 // Perform a load (the LHS). This performs the checks for
130 // null dereferences, and so on.
131 ExplodedNodeSet Tmp;
132 SVal location = LeftV;
133 evalLoad(Tmp, B, LHS, *it, state, location);
134
135 for (ExplodedNodeSet::iterator I = Tmp.begin(), E = Tmp.end(); I != E;
136 ++I) {
137
138 state = (*I)->getState();
139 const LocationContext *LCtx = (*I)->getLocationContext();
140 SVal V = state->getSVal(LHS, LCtx);
141
142 // Get the computation type.
143 QualType CTy =
144 cast<CompoundAssignOperator>(B)->getComputationResultType();
145 CTy = getContext().getCanonicalType(CTy);
146
147 QualType CLHSTy =
148 cast<CompoundAssignOperator>(B)->getComputationLHSType();
149 CLHSTy = getContext().getCanonicalType(CLHSTy);
150
151 QualType LTy = getContext().getCanonicalType(LHS->getType());
152
153 // Promote LHS.
154 V = svalBuilder.evalCast(V, CLHSTy, LTy);
155
156 // Compute the result of the operation.
157 SVal Result = svalBuilder.evalCast(evalBinOp(state, Op, V, RightV, CTy),
158 B->getType(), CTy);
159
160 // EXPERIMENTAL: "Conjured" symbols.
161 // FIXME: Handle structs.
162
163 SVal LHSVal;
164
165 if (Result.isUnknown()) {
166 // The symbolic value is actually for the type of the left-hand side
167 // expression, not the computation type, as this is the value the
168 // LValue on the LHS will bind to.
169 LHSVal = svalBuilder.conjureSymbolVal(nullptr, B->getRHS(), LCtx, LTy,
170 currBldrCtx->blockCount());
171 // However, we need to convert the symbol to the computation type.
172 Result = svalBuilder.evalCast(LHSVal, CTy, LTy);
173 }
174 else {
175 // The left-hand side may bind to a different value then the
176 // computation type.
177 LHSVal = svalBuilder.evalCast(Result, LTy, CTy);
178 }
179
180 // In C++, assignment and compound assignment operators return an
181 // lvalue.
182 if (B->isGLValue())
183 state = state->BindExpr(B, LCtx, location);
184 else
185 state = state->BindExpr(B, LCtx, Result);
186
187 evalStore(Tmp2, B, LHS, *I, state, location, LHSVal);
188 }
189 }
190
191 // FIXME: postvisits eventually go in ::Visit()
192 getCheckerManager().runCheckersForPostStmt(Dst, Tmp2, B, *this);
193}
194
195void ExprEngine::VisitBlockExpr(const BlockExpr *BE, ExplodedNode *Pred,
196 ExplodedNodeSet &Dst) {
197
198 CanQualType T = getContext().getCanonicalType(BE->getType());
199
200 const BlockDecl *BD = BE->getBlockDecl();
201 // Get the value of the block itself.
202 SVal V = svalBuilder.getBlockPointer(BD, T,
203 Pred->getLocationContext(),
204 currBldrCtx->blockCount());
205
206 ProgramStateRef State = Pred->getState();
207
208 // If we created a new MemRegion for the block, we should explicitly bind
209 // the captured variables.
210 if (const BlockDataRegion *BDR =
211 dyn_cast_or_null<BlockDataRegion>(V.getAsRegion())) {
212
213 BlockDataRegion::referenced_vars_iterator I = BDR->referenced_vars_begin(),
214 E = BDR->referenced_vars_end();
215
216 auto CI = BD->capture_begin();
217 auto CE = BD->capture_end();
218 for (; I != E; ++I) {
219 const VarRegion *capturedR = I.getCapturedRegion();
220 const TypedValueRegion *originalR = I.getOriginalRegion();
221
222 // If the capture had a copy expression, use the result of evaluating
223 // that expression, otherwise use the original value.
224 // We rely on the invariant that the block declaration's capture variables
225 // are a prefix of the BlockDataRegion's referenced vars (which may include
226 // referenced globals, etc.) to enable fast lookup of the capture for a
227 // given referenced var.
228 const Expr *copyExpr = nullptr;
229 if (CI != CE) {
230 assert(CI->getVariable() == capturedR->getDecl());
231 copyExpr = CI->getCopyExpr();
232 CI++;
233 }
234
235 if (capturedR != originalR) {
236 SVal originalV;
237 const LocationContext *LCtx = Pred->getLocationContext();
238 if (copyExpr) {
239 originalV = State->getSVal(copyExpr, LCtx);
240 } else {
241 originalV = State->getSVal(loc::MemRegionVal(originalR));
242 }
243 State = State->bindLoc(loc::MemRegionVal(capturedR), originalV, LCtx);
244 }
245 }
246 }
247
248 ExplodedNodeSet Tmp;
249 StmtNodeBuilder Bldr(Pred, Tmp, *currBldrCtx);
250 Bldr.generateNode(BE, Pred,
251 State->BindExpr(BE, Pred->getLocationContext(), V),
252 nullptr, ProgramPoint::PostLValueKind);
253
254 // FIXME: Move all post/pre visits to ::Visit().
255 getCheckerManager().runCheckersForPostStmt(Dst, Tmp, BE, *this);
256}
257
258ProgramStateRef ExprEngine::handleLValueBitCast(
259 ProgramStateRef state, const Expr* Ex, const LocationContext* LCtx,
260 QualType T, QualType ExTy, const CastExpr* CastE, StmtNodeBuilder& Bldr,
261 ExplodedNode* Pred) {
262 if (T->isLValueReferenceType()) {
263 assert(!CastE->getType()->isLValueReferenceType());
264 ExTy = getContext().getLValueReferenceType(ExTy);
265 } else if (T->isRValueReferenceType()) {
266 assert(!CastE->getType()->isRValueReferenceType());
267 ExTy = getContext().getRValueReferenceType(ExTy);
268 }
269 // Delegate to SValBuilder to process.
270 SVal OrigV = state->getSVal(Ex, LCtx);
271 SVal V = svalBuilder.evalCast(OrigV, T, ExTy);
272 // Negate the result if we're treating the boolean as a signed i1
273 if (CastE->getCastKind() == CK_BooleanToSignedIntegral && V.isValid())
274 V = svalBuilder.evalMinus(V.castAs<NonLoc>());
275
276 state = state->BindExpr(CastE, LCtx, V);
277 if (V.isUnknown() && !OrigV.isUnknown()) {
278 state = escapeValues(state, OrigV, PSK_EscapeOther);
279 }
280 Bldr.generateNode(CastE, Pred, state);
281
282 return state;
283}
284
285void ExprEngine::VisitCast(const CastExpr *CastE, const Expr *Ex,
286 ExplodedNode *Pred, ExplodedNodeSet &Dst) {
287
288 ExplodedNodeSet dstPreStmt;
289 getCheckerManager().runCheckersForPreStmt(dstPreStmt, Pred, CastE, *this);
290
291 if (CastE->getCastKind() == CK_LValueToRValue ||
292 CastE->getCastKind() == CK_LValueToRValueBitCast) {
293 for (ExplodedNodeSet::iterator I = dstPreStmt.begin(), E = dstPreStmt.end();
294 I!=E; ++I) {
295 ExplodedNode *subExprNode = *I;
296 ProgramStateRef state = subExprNode->getState();
297 const LocationContext *LCtx = subExprNode->getLocationContext();
298 evalLoad(Dst, CastE, CastE, subExprNode, state, state->getSVal(Ex, LCtx));
299 }
300 return;
301 }
302
303 // All other casts.
304 QualType T = CastE->getType();
305 QualType ExTy = Ex->getType();
306
307 if (const ExplicitCastExpr *ExCast=dyn_cast_or_null<ExplicitCastExpr>(CastE))
308 T = ExCast->getTypeAsWritten();
309
310 StmtNodeBuilder Bldr(dstPreStmt, Dst, *currBldrCtx);
311 for (ExplodedNodeSet::iterator I = dstPreStmt.begin(), E = dstPreStmt.end();
312 I != E; ++I) {
313
314 Pred = *I;
315 ProgramStateRef state = Pred->getState();
316 const LocationContext *LCtx = Pred->getLocationContext();
317
318 switch (CastE->getCastKind()) {
319 case CK_LValueToRValue:
320 case CK_LValueToRValueBitCast:
321 llvm_unreachable("LValueToRValue casts handled earlier.");
322 case CK_ToVoid:
323 continue;
324 // The analyzer doesn't do anything special with these casts,
325 // since it understands retain/release semantics already.
326 case CK_ARCProduceObject:
327 case CK_ARCConsumeObject:
328 case CK_ARCReclaimReturnedObject:
329 case CK_ARCExtendBlockObject: // Fall-through.
330 case CK_CopyAndAutoreleaseBlockObject:
331 // The analyser can ignore atomic casts for now, although some future
332 // checkers may want to make certain that you're not modifying the same
333 // value through atomic and nonatomic pointers.
334 case CK_AtomicToNonAtomic:
335 case CK_NonAtomicToAtomic:
336 // True no-ops.
337 case CK_NoOp:
338 case CK_ConstructorConversion:
339 case CK_UserDefinedConversion:
340 case CK_FunctionToPointerDecay:
341 case CK_BuiltinFnToFnPtr: {
342 // Copy the SVal of Ex to CastE.
343 ProgramStateRef state = Pred->getState();
344 const LocationContext *LCtx = Pred->getLocationContext();
345 SVal V = state->getSVal(Ex, LCtx);
346 state = state->BindExpr(CastE, LCtx, V);
347 Bldr.generateNode(CastE, Pred, state);
348 continue;
349 }
350 case CK_MemberPointerToBoolean:
351 case CK_PointerToBoolean: {
352 SVal V = state->getSVal(Ex, LCtx);
353 auto PTMSV = V.getAs<nonloc::PointerToMember>();
354 if (PTMSV)
355 V = svalBuilder.makeTruthVal(!PTMSV->isNullMemberPointer(), ExTy);
356 if (V.isUndef() || PTMSV) {
357 state = state->BindExpr(CastE, LCtx, V);
358 Bldr.generateNode(CastE, Pred, state);
359 continue;
360 }
361 // Explicitly proceed with default handler for this case cascade.
362 state =
363 handleLValueBitCast(state, Ex, LCtx, T, ExTy, CastE, Bldr, Pred);
364 continue;
365 }
366 case CK_Dependent:
367 case CK_ArrayToPointerDecay:
368 case CK_BitCast:
369 case CK_AddressSpaceConversion:
370 case CK_BooleanToSignedIntegral:
371 case CK_IntegralToPointer:
372 case CK_PointerToIntegral: {
373 SVal V = state->getSVal(Ex, LCtx);
374 if (isa<nonloc::PointerToMember>(V)) {
375 state = state->BindExpr(CastE, LCtx, UnknownVal());
376 Bldr.generateNode(CastE, Pred, state);
377 continue;
378 }
379 // Explicitly proceed with default handler for this case cascade.
380 state =
381 handleLValueBitCast(state, Ex, LCtx, T, ExTy, CastE, Bldr, Pred);
382 continue;
383 }
384 case CK_IntegralToBoolean:
385 case CK_IntegralToFloating:
386 case CK_FloatingToIntegral:
387 case CK_FloatingToBoolean:
388 case CK_FloatingCast:
389 case CK_FloatingRealToComplex:
390 case CK_FloatingComplexToReal:
391 case CK_FloatingComplexToBoolean:
392 case CK_FloatingComplexCast:
393 case CK_FloatingComplexToIntegralComplex:
394 case CK_IntegralRealToComplex:
395 case CK_IntegralComplexToReal:
396 case CK_IntegralComplexToBoolean:
397 case CK_IntegralComplexCast:
398 case CK_IntegralComplexToFloatingComplex:
399 case CK_CPointerToObjCPointerCast:
400 case CK_BlockPointerToObjCPointerCast:
401 case CK_AnyPointerToBlockPointerCast:
402 case CK_ObjCObjectLValueCast:
403 case CK_ZeroToOCLOpaqueType:
404 case CK_IntToOCLSampler:
405 case CK_LValueBitCast:
406 case CK_FloatingToFixedPoint:
407 case CK_FixedPointToFloating:
408 case CK_FixedPointCast:
409 case CK_FixedPointToBoolean:
410 case CK_FixedPointToIntegral:
411 case CK_IntegralToFixedPoint: {
412 state =
413 handleLValueBitCast(state, Ex, LCtx, T, ExTy, CastE, Bldr, Pred);
414 continue;
415 }
416 case CK_IntegralCast: {
417 // Delegate to SValBuilder to process.
418 SVal V = state->getSVal(Ex, LCtx);
419 if (AMgr.options.ShouldSupportSymbolicIntegerCasts)
420 V = svalBuilder.evalCast(V, T, ExTy);
421 else
422 V = svalBuilder.evalIntegralCast(state, V, T, ExTy);
423 state = state->BindExpr(CastE, LCtx, V);
424 Bldr.generateNode(CastE, Pred, state);
425 continue;
426 }
427 case CK_DerivedToBase:
428 case CK_UncheckedDerivedToBase: {
429 // For DerivedToBase cast, delegate to the store manager.
430 SVal val = state->getSVal(Ex, LCtx);
431 val = getStoreManager().evalDerivedToBase(val, CastE);
432 state = state->BindExpr(CastE, LCtx, val);
433 Bldr.generateNode(CastE, Pred, state);
434 continue;
435 }
436 // Handle C++ dyn_cast.
437 case CK_Dynamic: {
438 SVal val = state->getSVal(Ex, LCtx);
439
440 // Compute the type of the result.
441 QualType resultType = CastE->getType();
442 if (CastE->isGLValue())
443 resultType = getContext().getPointerType(resultType);
444
445 bool Failed = true;
446
447 // Check if the value being cast does not evaluates to 0.
448 if (!val.isZeroConstant())
449 if (Optional<SVal> V =
450 StateMgr.getStoreManager().evalBaseToDerived(val, T)) {
451 val = *V;
452 Failed = false;
453 }
454
455 if (Failed) {
456 if (T->isReferenceType()) {
457 // A bad_cast exception is thrown if input value is a reference.
458 // Currently, we model this, by generating a sink.
459 Bldr.generateSink(CastE, Pred, state);
460 continue;
461 } else {
462 // If the cast fails on a pointer, bind to 0.
463 state = state->BindExpr(CastE, LCtx,
464 svalBuilder.makeNullWithType(resultType));
465 }
466 } else {
467 // If we don't know if the cast succeeded, conjure a new symbol.
468 if (val.isUnknown()) {
469 DefinedOrUnknownSVal NewSym =
470 svalBuilder.conjureSymbolVal(nullptr, CastE, LCtx, resultType,
471 currBldrCtx->blockCount());
472 state = state->BindExpr(CastE, LCtx, NewSym);
473 } else
474 // Else, bind to the derived region value.
475 state = state->BindExpr(CastE, LCtx, val);
476 }
477 Bldr.generateNode(CastE, Pred, state);
478 continue;
479 }
480 case CK_BaseToDerived: {
481 SVal val = state->getSVal(Ex, LCtx);
482 QualType resultType = CastE->getType();
483 if (CastE->isGLValue())
484 resultType = getContext().getPointerType(resultType);
485
486 if (!val.isConstant()) {
487 Optional<SVal> V = getStoreManager().evalBaseToDerived(val, T);
488 val = V ? *V : UnknownVal();
489 }
490
491 // Failed to cast or the result is unknown, fall back to conservative.
492 if (val.isUnknown()) {
493 val =
494 svalBuilder.conjureSymbolVal(nullptr, CastE, LCtx, resultType,
495 currBldrCtx->blockCount());
496 }
497 state = state->BindExpr(CastE, LCtx, val);
498 Bldr.generateNode(CastE, Pred, state);
499 continue;
500 }
501 case CK_NullToPointer: {
502 SVal V = svalBuilder.makeNullWithType(CastE->getType());
503 state = state->BindExpr(CastE, LCtx, V);
504 Bldr.generateNode(CastE, Pred, state);
505 continue;
506 }
507 case CK_NullToMemberPointer: {
508 SVal V = svalBuilder.getMemberPointer(nullptr);
509 state = state->BindExpr(CastE, LCtx, V);
510 Bldr.generateNode(CastE, Pred, state);
511 continue;
512 }
513 case CK_DerivedToBaseMemberPointer:
514 case CK_BaseToDerivedMemberPointer:
515 case CK_ReinterpretMemberPointer: {
516 SVal V = state->getSVal(Ex, LCtx);
517 if (auto PTMSV = V.getAs<nonloc::PointerToMember>()) {
518 SVal CastedPTMSV =
519 svalBuilder.makePointerToMember(getBasicVals().accumCXXBase(
520 CastE->path(), *PTMSV, CastE->getCastKind()));
521 state = state->BindExpr(CastE, LCtx, CastedPTMSV);
522 Bldr.generateNode(CastE, Pred, state);
523 continue;
524 }
525 // Explicitly proceed with default handler for this case cascade.
526 }
527 [[fallthrough]];
528 // Various C++ casts that are not handled yet.
529 case CK_ToUnion:
530 case CK_MatrixCast:
531 case CK_VectorSplat: {
532 QualType resultType = CastE->getType();
533 if (CastE->isGLValue())
534 resultType = getContext().getPointerType(resultType);
535 SVal result = svalBuilder.conjureSymbolVal(
536 /*symbolTag=*/nullptr, CastE, LCtx, resultType,
537 currBldrCtx->blockCount());
538 state = state->BindExpr(CastE, LCtx, result);
539 Bldr.generateNode(CastE, Pred, state);
540 continue;
541 }
542 }
543 }
544}
545
546void ExprEngine::VisitCompoundLiteralExpr(const CompoundLiteralExpr *CL,
547 ExplodedNode *Pred,
548 ExplodedNodeSet &Dst) {
549 StmtNodeBuilder B(Pred, Dst, *currBldrCtx);
550
551 ProgramStateRef State = Pred->getState();
552 const LocationContext *LCtx = Pred->getLocationContext();
553
554 const Expr *Init = CL->getInitializer();
555 SVal V = State->getSVal(CL->getInitializer(), LCtx);
556
557 if (isa<CXXConstructExpr, CXXStdInitializerListExpr>(Init)) {
558 // No work needed. Just pass the value up to this expression.
559 } else {
560 assert(isa<InitListExpr>(Init));
561 Loc CLLoc = State->getLValue(CL, LCtx);
562 State = State->bindLoc(CLLoc, V, LCtx);
563
564 if (CL->isGLValue())
565 V = CLLoc;
566 }
567
568 B.generateNode(CL, Pred, State->BindExpr(CL, LCtx, V));
569}
570
571void ExprEngine::VisitDeclStmt(const DeclStmt *DS, ExplodedNode *Pred,
572 ExplodedNodeSet &Dst) {
573 if (isa<TypedefNameDecl>(*DS->decl_begin())) {
574 // C99 6.7.7 "Any array size expressions associated with variable length
575 // array declarators are evaluated each time the declaration of the typedef
576 // name is reached in the order of execution."
577 // The checkers should know about typedef to be able to handle VLA size
578 // expressions.
579 ExplodedNodeSet DstPre;
580 getCheckerManager().runCheckersForPreStmt(DstPre, Pred, DS, *this);
581 getCheckerManager().runCheckersForPostStmt(Dst, DstPre, DS, *this);
582 return;
583 }
584
585 // Assumption: The CFG has one DeclStmt per Decl.
586 const VarDecl *VD = dyn_cast_or_null<VarDecl>(*DS->decl_begin());
587
588 if (!VD) {
589 //TODO:AZ: remove explicit insertion after refactoring is done.
590 Dst.insert(Pred);
591 return;
592 }
593
594 // FIXME: all pre/post visits should eventually be handled by ::Visit().
595 ExplodedNodeSet dstPreVisit;
596 getCheckerManager().runCheckersForPreStmt(dstPreVisit, Pred, DS, *this);
597
598 ExplodedNodeSet dstEvaluated;
599 StmtNodeBuilder B(dstPreVisit, dstEvaluated, *currBldrCtx);
600 for (ExplodedNodeSet::iterator I = dstPreVisit.begin(), E = dstPreVisit.end();
601 I!=E; ++I) {
602 ExplodedNode *N = *I;
603 ProgramStateRef state = N->getState();
604 const LocationContext *LC = N->getLocationContext();
605
606 // Decls without InitExpr are not initialized explicitly.
607 if (const Expr *InitEx = VD->getInit()) {
608
609 // Note in the state that the initialization has occurred.
610 ExplodedNode *UpdatedN = N;
611 SVal InitVal = state->getSVal(InitEx, LC);
612
613 assert(DS->isSingleDecl());
614 if (getObjectUnderConstruction(state, DS, LC)) {
615 state = finishObjectConstruction(state, DS, LC);
616 // We constructed the object directly in the variable.
617 // No need to bind anything.
618 B.generateNode(DS, UpdatedN, state);
619 } else {
620 // Recover some path-sensitivity if a scalar value evaluated to
621 // UnknownVal.
622 if (InitVal.isUnknown()) {
623 QualType Ty = InitEx->getType();
624 if (InitEx->isGLValue()) {
625 Ty = getContext().getPointerType(Ty);
626 }
627
628 InitVal = svalBuilder.conjureSymbolVal(nullptr, InitEx, LC, Ty,
629 currBldrCtx->blockCount());
630 }
631
632
633 B.takeNodes(UpdatedN);
634 ExplodedNodeSet Dst2;
635 evalBind(Dst2, DS, UpdatedN, state->getLValue(VD, LC), InitVal, true);
636 B.addNodes(Dst2);
637 }
638 }
639 else {
640 B.generateNode(DS, N, state);
641 }
642 }
643
644 getCheckerManager().runCheckersForPostStmt(Dst, B.getResults(), DS, *this);
645}
646
647void ExprEngine::VisitLogicalExpr(const BinaryOperator* B, ExplodedNode *Pred,
648 ExplodedNodeSet &Dst) {
649 // This method acts upon CFG elements for logical operators && and ||
650 // and attaches the value (true or false) to them as expressions.
651 // It doesn't produce any state splits.
652 // If we made it that far, we're past the point when we modeled the short
653 // circuit. It means that we should have precise knowledge about whether
654 // we've short-circuited. If we did, we already know the value we need to
655 // bind. If we didn't, the value of the RHS (casted to the boolean type)
656 // is the answer.
657 // Currently this method tries to figure out whether we've short-circuited
658 // by looking at the ExplodedGraph. This method is imperfect because there
659 // could inevitably have been merges that would have resulted in multiple
660 // potential path traversal histories. We bail out when we fail.
661 // Due to this ambiguity, a more reliable solution would have been to
662 // track the short circuit operation history path-sensitively until
663 // we evaluate the respective logical operator.
664 assert(B->getOpcode() == BO_LAnd ||
665 B->getOpcode() == BO_LOr);
666
667 StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx);
668 ProgramStateRef state = Pred->getState();
669
670 if (B->getType()->isVectorType()) {
671 // FIXME: We do not model vector arithmetic yet. When adding support for
672 // that, note that the CFG-based reasoning below does not apply, because
673 // logical operators on vectors are not short-circuit. Currently they are
674 // modeled as short-circuit in Clang CFG but this is incorrect.
675 // Do not set the value for the expression. It'd be UnknownVal by default.
676 Bldr.generateNode(B, Pred, state);
677 return;
678 }
679
680 ExplodedNode *N = Pred;
681 while (!N->getLocation().getAs<BlockEntrance>()) {
682 ProgramPoint P = N->getLocation();
683 assert(P.getAs<PreStmt>()|| P.getAs<PreStmtPurgeDeadSymbols>());
684 (void) P;
685 if (N->pred_size() != 1) {
686 // We failed to track back where we came from.
687 Bldr.generateNode(B, Pred, state);
688 return;
689 }
690 N = *N->pred_begin();
691 }
692
693 if (N->pred_size() != 1) {
694 // We failed to track back where we came from.
695 Bldr.generateNode(B, Pred, state);
696 return;
697 }
698
699 N = *N->pred_begin();
700 BlockEdge BE = N->getLocation().castAs<BlockEdge>();
701 SVal X;
702
703 // Determine the value of the expression by introspecting how we
704 // got this location in the CFG. This requires looking at the previous
705 // block we were in and what kind of control-flow transfer was involved.
706 const CFGBlock *SrcBlock = BE.getSrc();
707 // The only terminator (if there is one) that makes sense is a logical op.
708 CFGTerminator T = SrcBlock->getTerminator();
709 if (const BinaryOperator *Term = cast_or_null<BinaryOperator>(T.getStmt())) {
710 (void) Term;
711 assert(Term->isLogicalOp());
712 assert(SrcBlock->succ_size() == 2);
713 // Did we take the true or false branch?
714 unsigned constant = (*SrcBlock->succ_begin() == BE.getDst()) ? 1 : 0;
715 X = svalBuilder.makeIntVal(constant, B->getType());
716 }
717 else {
718 // If there is no terminator, by construction the last statement
719 // in SrcBlock is the value of the enclosing expression.
720 // However, we still need to constrain that value to be 0 or 1.
721 assert(!SrcBlock->empty());
722 CFGStmt Elem = SrcBlock->rbegin()->castAs<CFGStmt>();
723 const Expr *RHS = cast<Expr>(Elem.getStmt());
724 SVal RHSVal = N->getState()->getSVal(RHS, Pred->getLocationContext());
725
726 if (RHSVal.isUndef()) {
727 X = RHSVal;
728 } else {
729 // We evaluate "RHSVal != 0" expression which result in 0 if the value is
730 // known to be false, 1 if the value is known to be true and a new symbol
731 // when the assumption is unknown.
732 nonloc::ConcreteInt Zero(getBasicVals().getValue(0, B->getType()));
733 X = evalBinOp(N->getState(), BO_NE,
734 svalBuilder.evalCast(RHSVal, B->getType(), RHS->getType()),
735 Zero, B->getType());
736 }
737 }
738 Bldr.generateNode(B, Pred, state->BindExpr(B, Pred->getLocationContext(), X));
739}
740
741void ExprEngine::VisitInitListExpr(const InitListExpr *IE,
742 ExplodedNode *Pred,
743 ExplodedNodeSet &Dst) {
744 StmtNodeBuilder B(Pred, Dst, *currBldrCtx);
745
746 ProgramStateRef state = Pred->getState();
747 const LocationContext *LCtx = Pred->getLocationContext();
748 QualType T = getContext().getCanonicalType(IE->getType());
749 unsigned NumInitElements = IE->getNumInits();
750
751 if (!IE->isGLValue() && !IE->isTransparent() &&
752 (T->isArrayType() || T->isRecordType() || T->isVectorType() ||
753 T->isAnyComplexType())) {
754 llvm::ImmutableList<SVal> vals = getBasicVals().getEmptySValList();
755
756 // Handle base case where the initializer has no elements.
757 // e.g: static int* myArray[] = {};
758 if (NumInitElements == 0) {
759 SVal V = svalBuilder.makeCompoundVal(T, vals);
760 B.generateNode(IE, Pred, state->BindExpr(IE, LCtx, V));
761 return;
762 }
763
764 for (const Stmt *S : llvm::reverse(*IE)) {
765 SVal V = state->getSVal(cast<Expr>(S), LCtx);
766 vals = getBasicVals().prependSVal(V, vals);
767 }
768
769 B.generateNode(IE, Pred,
770 state->BindExpr(IE, LCtx,
771 svalBuilder.makeCompoundVal(T, vals)));
772 return;
773 }
774
775 // Handle scalars: int{5} and int{} and GLvalues.
776 // Note, if the InitListExpr is a GLvalue, it means that there is an address
777 // representing it, so it must have a single init element.
778 assert(NumInitElements <= 1);
779
780 SVal V;
781 if (NumInitElements == 0)
782 V = getSValBuilder().makeZeroVal(T);
783 else
784 V = state->getSVal(IE->getInit(0), LCtx);
785
786 B.generateNode(IE, Pred, state->BindExpr(IE, LCtx, V));
787}
788
789void ExprEngine::VisitGuardedExpr(const Expr *Ex,
790 const Expr *L,
791 const Expr *R,
792 ExplodedNode *Pred,
793 ExplodedNodeSet &Dst) {
794 assert(L && R);
795
796 StmtNodeBuilder B(Pred, Dst, *currBldrCtx);
797 ProgramStateRef state = Pred->getState();
798 const LocationContext *LCtx = Pred->getLocationContext();
799 const CFGBlock *SrcBlock = nullptr;
800
801 // Find the predecessor block.
802 ProgramStateRef SrcState = state;
803 for (const ExplodedNode *N = Pred ; N ; N = *N->pred_begin()) {
804 ProgramPoint PP = N->getLocation();
805 if (PP.getAs<PreStmtPurgeDeadSymbols>() || PP.getAs<BlockEntrance>()) {
806 // If the state N has multiple predecessors P, it means that successors
807 // of P are all equivalent.
808 // In turn, that means that all nodes at P are equivalent in terms
809 // of observable behavior at N, and we can follow any of them.
810 // FIXME: a more robust solution which does not walk up the tree.
811 continue;
812 }
813 SrcBlock = PP.castAs<BlockEdge>().getSrc();
814 SrcState = N->getState();
815 break;
816 }
817
818 assert(SrcBlock && "missing function entry");
819
820 // Find the last expression in the predecessor block. That is the
821 // expression that is used for the value of the ternary expression.
822 bool hasValue = false;
823 SVal V;
824
825 for (CFGElement CE : llvm::reverse(*SrcBlock)) {
826 if (Optional<CFGStmt> CS = CE.getAs<CFGStmt>()) {
827 const Expr *ValEx = cast<Expr>(CS->getStmt());
828 ValEx = ValEx->IgnoreParens();
829
830 // For GNU extension '?:' operator, the left hand side will be an
831 // OpaqueValueExpr, so get the underlying expression.
832 if (const OpaqueValueExpr *OpaqueEx = dyn_cast<OpaqueValueExpr>(L))
833 L = OpaqueEx->getSourceExpr();
834
835 // If the last expression in the predecessor block matches true or false
836 // subexpression, get its the value.
837 if (ValEx == L->IgnoreParens() || ValEx == R->IgnoreParens()) {
838 hasValue = true;
839 V = SrcState->getSVal(ValEx, LCtx);
840 }
841 break;
842 }
843 }
844
845 if (!hasValue)
846 V = svalBuilder.conjureSymbolVal(nullptr, Ex, LCtx,
847 currBldrCtx->blockCount());
848
849 // Generate a new node with the binding from the appropriate path.
850 B.generateNode(Ex, Pred, state->BindExpr(Ex, LCtx, V, true));
851}
852
853void ExprEngine::
854VisitOffsetOfExpr(const OffsetOfExpr *OOE,
855 ExplodedNode *Pred, ExplodedNodeSet &Dst) {
856 StmtNodeBuilder B(Pred, Dst, *currBldrCtx);
857 Expr::EvalResult Result;
858 if (OOE->EvaluateAsInt(Result, getContext())) {
859 APSInt IV = Result.Val.getInt();
860 assert(IV.getBitWidth() == getContext().getTypeSize(OOE->getType()));
861 assert(OOE->getType()->castAs<BuiltinType>()->isInteger());
862 assert(IV.isSigned() == OOE->getType()->isSignedIntegerType());
863 SVal X = svalBuilder.makeIntVal(IV);
864 B.generateNode(OOE, Pred,
865 Pred->getState()->BindExpr(OOE, Pred->getLocationContext(),
866 X));
867 }
868 // FIXME: Handle the case where __builtin_offsetof is not a constant.
869}
870
871
872void ExprEngine::
873VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *Ex,
874 ExplodedNode *Pred,
875 ExplodedNodeSet &Dst) {
876 // FIXME: Prechecks eventually go in ::Visit().
877 ExplodedNodeSet CheckedSet;
878 getCheckerManager().runCheckersForPreStmt(CheckedSet, Pred, Ex, *this);
879
880 ExplodedNodeSet EvalSet;
881 StmtNodeBuilder Bldr(CheckedSet, EvalSet, *currBldrCtx);
882
883 QualType T = Ex->getTypeOfArgument();
884
885 for (ExplodedNodeSet::iterator I = CheckedSet.begin(), E = CheckedSet.end();
886 I != E; ++I) {
887 if (Ex->getKind() == UETT_SizeOf) {
888 if (!T->isIncompleteType() && !T->isConstantSizeType()) {
889 assert(T->isVariableArrayType() && "Unknown non-constant-sized type.");
890
891 // FIXME: Add support for VLA type arguments and VLA expressions.
892 // When that happens, we should probably refactor VLASizeChecker's code.
893 continue;
894 } else if (T->getAs<ObjCObjectType>()) {
895 // Some code tries to take the sizeof an ObjCObjectType, relying that
896 // the compiler has laid out its representation. Just report Unknown
897 // for these.
898 continue;
899 }
900 }
901
902 APSInt Value = Ex->EvaluateKnownConstInt(getContext());
903 CharUnits amt = CharUnits::fromQuantity(Value.getZExtValue());
904
905 ProgramStateRef state = (*I)->getState();
906 state = state->BindExpr(Ex, (*I)->getLocationContext(),
907 svalBuilder.makeIntVal(amt.getQuantity(),
908 Ex->getType()));
909 Bldr.generateNode(Ex, *I, state);
910 }
911
912 getCheckerManager().runCheckersForPostStmt(Dst, EvalSet, Ex, *this);
913}
914
915void ExprEngine::handleUOExtension(ExplodedNodeSet::iterator I,
916 const UnaryOperator *U,
917 StmtNodeBuilder &Bldr) {
918 // FIXME: We can probably just have some magic in Environment::getSVal()
919 // that propagates values, instead of creating a new node here.
920 //
921 // Unary "+" is a no-op, similar to a parentheses. We still have places
922 // where it may be a block-level expression, so we need to
923 // generate an extra node that just propagates the value of the
924 // subexpression.
925 const Expr *Ex = U->getSubExpr()->IgnoreParens();
926 ProgramStateRef state = (*I)->getState();
927 const LocationContext *LCtx = (*I)->getLocationContext();
928 Bldr.generateNode(U, *I, state->BindExpr(U, LCtx,
929 state->getSVal(Ex, LCtx)));
930}
931
932void ExprEngine::VisitUnaryOperator(const UnaryOperator* U, ExplodedNode *Pred,
933 ExplodedNodeSet &Dst) {
934 // FIXME: Prechecks eventually go in ::Visit().
935 ExplodedNodeSet CheckedSet;
936 getCheckerManager().runCheckersForPreStmt(CheckedSet, Pred, U, *this);
937
938 ExplodedNodeSet EvalSet;
939 StmtNodeBuilder Bldr(CheckedSet, EvalSet, *currBldrCtx);
940
941 for (ExplodedNodeSet::iterator I = CheckedSet.begin(), E = CheckedSet.end();
942 I != E; ++I) {
943 switch (U->getOpcode()) {
944 default: {
945 Bldr.takeNodes(*I);
946 ExplodedNodeSet Tmp;
947 VisitIncrementDecrementOperator(U, *I, Tmp);
948 Bldr.addNodes(Tmp);
949 break;
950 }
951 case UO_Real: {
952 const Expr *Ex = U->getSubExpr()->IgnoreParens();
953
954 // FIXME: We don't have complex SValues yet.
955 if (Ex->getType()->isAnyComplexType()) {
956 // Just report "Unknown."
957 break;
958 }
959
960 // For all other types, UO_Real is an identity operation.
961 assert (U->getType() == Ex->getType());
962 ProgramStateRef state = (*I)->getState();
963 const LocationContext *LCtx = (*I)->getLocationContext();
964 Bldr.generateNode(U, *I, state->BindExpr(U, LCtx,
965 state->getSVal(Ex, LCtx)));
966 break;
967 }
968
969 case UO_Imag: {
970 const Expr *Ex = U->getSubExpr()->IgnoreParens();
971 // FIXME: We don't have complex SValues yet.
972 if (Ex->getType()->isAnyComplexType()) {
973 // Just report "Unknown."
974 break;
975 }
976 // For all other types, UO_Imag returns 0.
977 ProgramStateRef state = (*I)->getState();
978 const LocationContext *LCtx = (*I)->getLocationContext();
979 SVal X = svalBuilder.makeZeroVal(Ex->getType());
980 Bldr.generateNode(U, *I, state->BindExpr(U, LCtx, X));
981 break;
982 }
983
984 case UO_AddrOf: {
985 // Process pointer-to-member address operation.
986 const Expr *Ex = U->getSubExpr()->IgnoreParens();
987 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Ex)) {
988 const ValueDecl *VD = DRE->getDecl();
989
990 if (isa<CXXMethodDecl, FieldDecl, IndirectFieldDecl>(VD)) {
991 ProgramStateRef State = (*I)->getState();
992 const LocationContext *LCtx = (*I)->getLocationContext();
993 SVal SV = svalBuilder.getMemberPointer(cast<NamedDecl>(VD));
994 Bldr.generateNode(U, *I, State->BindExpr(U, LCtx, SV));
995 break;
996 }
997 }
998 // Explicitly proceed with default handler for this case cascade.
999 handleUOExtension(I, U, Bldr);
1000 break;
1001 }
1002 case UO_Plus:
1003 assert(!U->isGLValue());
1004 [[fallthrough]];
1005 case UO_Deref:
1006 case UO_Extension: {
1007 handleUOExtension(I, U, Bldr);
1008 break;
1009 }
1010
1011 case UO_LNot:
1012 case UO_Minus:
1013 case UO_Not: {
1014 assert (!U->isGLValue());
1015 const Expr *Ex = U->getSubExpr()->IgnoreParens();
1016 ProgramStateRef state = (*I)->getState();
1017 const LocationContext *LCtx = (*I)->getLocationContext();
1018
1019 // Get the value of the subexpression.
1020 SVal V = state->getSVal(Ex, LCtx);
1021
1022 if (V.isUnknownOrUndef()) {
1023 Bldr.generateNode(U, *I, state->BindExpr(U, LCtx, V));
1024 break;
1025 }
1026
1027 switch (U->getOpcode()) {
1028 default:
1029 llvm_unreachable("Invalid Opcode.");
1030 case UO_Not:
1031 // FIXME: Do we need to handle promotions?
1032 state = state->BindExpr(
1033 U, LCtx, svalBuilder.evalComplement(V.castAs<NonLoc>()));
1034 break;
1035 case UO_Minus:
1036 // FIXME: Do we need to handle promotions?
1037 state = state->BindExpr(U, LCtx,
1038 svalBuilder.evalMinus(V.castAs<NonLoc>()));
1039 break;
1040 case UO_LNot:
1041 // C99 6.5.3.3: "The expression !E is equivalent to (0==E)."
1042 //
1043 // Note: technically we do "E == 0", but this is the same in the
1044 // transfer functions as "0 == E".
1045 SVal Result;
1046 if (Optional<Loc> LV = V.getAs<Loc>()) {
1047 Loc X = svalBuilder.makeNullWithType(Ex->getType());
1048 Result = evalBinOp(state, BO_EQ, *LV, X, U->getType());
1049 } else if (Ex->getType()->isFloatingType()) {
1050 // FIXME: handle floating point types.
1051 Result = UnknownVal();
1052 } else {
1053 nonloc::ConcreteInt X(getBasicVals().getValue(0, Ex->getType()));
1054 Result = evalBinOp(state, BO_EQ, V.castAs<NonLoc>(), X,
1055 U->getType());
1056 }
1057
1058 state = state->BindExpr(U, LCtx, Result);
1059 break;
1060 }
1061 Bldr.generateNode(U, *I, state);
1062 break;
1063 }
1064 }
1065 }
1066
1067 getCheckerManager().runCheckersForPostStmt(Dst, EvalSet, U, *this);
1068}
1069
1070void ExprEngine::VisitIncrementDecrementOperator(const UnaryOperator* U,
1071 ExplodedNode *Pred,
1072 ExplodedNodeSet &Dst) {
1073 // Handle ++ and -- (both pre- and post-increment).
1074 assert (U->isIncrementDecrementOp());
1075 const Expr *Ex = U->getSubExpr()->IgnoreParens();
1076
1077 const LocationContext *LCtx = Pred->getLocationContext();
1078 ProgramStateRef state = Pred->getState();
1079 SVal loc = state->getSVal(Ex, LCtx);
1080
1081 // Perform a load.
1082 ExplodedNodeSet Tmp;
1083 evalLoad(Tmp, U, Ex, Pred, state, loc);
1084
1085 ExplodedNodeSet Dst2;
1086 StmtNodeBuilder Bldr(Tmp, Dst2, *currBldrCtx);
1087 for (ExplodedNodeSet::iterator I=Tmp.begin(), E=Tmp.end();I!=E;++I) {
1088
1089 state = (*I)->getState();
1090 assert(LCtx == (*I)->getLocationContext());
1091 SVal V2_untested = state->getSVal(Ex, LCtx);
1092
1093 // Propagate unknown and undefined values.
1094 if (V2_untested.isUnknownOrUndef()) {
1095 state = state->BindExpr(U, LCtx, V2_untested);
1096
1097 // Perform the store, so that the uninitialized value detection happens.
1098 Bldr.takeNodes(*I);
1099 ExplodedNodeSet Dst3;
1100 evalStore(Dst3, U, Ex, *I, state, loc, V2_untested);
1101 Bldr.addNodes(Dst3);
1102
1103 continue;
1104 }
1105 DefinedSVal V2 = V2_untested.castAs<DefinedSVal>();
1106
1107 // Handle all other values.
1108 BinaryOperator::Opcode Op = U->isIncrementOp() ? BO_Add : BO_Sub;
1109
1110 // If the UnaryOperator has non-location type, use its type to create the
1111 // constant value. If the UnaryOperator has location type, create the
1112 // constant with int type and pointer width.
1113 SVal RHS;
1114 SVal Result;
1115
1116 if (U->getType()->isAnyPointerType())
1117 RHS = svalBuilder.makeArrayIndex(1);
1118 else if (U->getType()->isIntegralOrEnumerationType())
1119 RHS = svalBuilder.makeIntVal(1, U->getType());
1120 else
1121 RHS = UnknownVal();
1122
1123 // The use of an operand of type bool with the ++ operators is deprecated
1124 // but valid until C++17. And if the operand of the ++ operator is of type
1125 // bool, it is set to true until C++17. Note that for '_Bool', it is also
1126 // set to true when it encounters ++ operator.
1127 if (U->getType()->isBooleanType() && U->isIncrementOp())
1128 Result = svalBuilder.makeTruthVal(true, U->getType());
1129 else
1130 Result = evalBinOp(state, Op, V2, RHS, U->getType());
1131
1132 // Conjure a new symbol if necessary to recover precision.
1133 if (Result.isUnknown()){
1134 DefinedOrUnknownSVal SymVal =
1135 svalBuilder.conjureSymbolVal(nullptr, U, LCtx,
1136 currBldrCtx->blockCount());
1137 Result = SymVal;
1138
1139 // If the value is a location, ++/-- should always preserve
1140 // non-nullness. Check if the original value was non-null, and if so
1141 // propagate that constraint.
1142 if (Loc::isLocType(U->getType())) {
1143 DefinedOrUnknownSVal Constraint =
1144 svalBuilder.evalEQ(state, V2,svalBuilder.makeZeroVal(U->getType()));
1145
1146 if (!state->assume(Constraint, true)) {
1147 // It isn't feasible for the original value to be null.
1148 // Propagate this constraint.
1149 Constraint = svalBuilder.evalEQ(state, SymVal,
1150 svalBuilder.makeZeroVal(U->getType()));
1151
1152 state = state->assume(Constraint, false);
1153 assert(state);
1154 }
1155 }
1156 }
1157
1158 // Since the lvalue-to-rvalue conversion is explicit in the AST,
1159 // we bind an l-value if the operator is prefix and an lvalue (in C++).
1160 if (U->isGLValue())
1161 state = state->BindExpr(U, LCtx, loc);
1162 else
1163 state = state->BindExpr(U, LCtx, U->isPostfix() ? V2 : Result);
1164
1165 // Perform the store.
1166 Bldr.takeNodes(*I);
1167 ExplodedNodeSet Dst3;
1168 evalStore(Dst3, U, Ex, *I, state, loc, Result);
1169 Bldr.addNodes(Dst3);
1170 }
1171 Dst.insert(Dst2);
1172}
1173

source code of clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp