1 // UndefCapturedBlockVarChecker.cpp - Uninitialized captured vars -*- 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 // This checker detects blocks that capture uninitialized values. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "ClangSACheckers.h" 15 #include "clang/StaticAnalyzer/Core/Checker.h" 16 #include "clang/StaticAnalyzer/Core/CheckerManager.h" 17 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h" 18 #include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h" 19 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h" 20 #include "llvm/ADT/SmallString.h" 21 #include "llvm/Support/raw_ostream.h" 22 23 using namespace clang; 24 using namespace ento; 25 26 namespace { 27 class UndefCapturedBlockVarChecker 28 : public Checker< check::PostStmt<BlockExpr> > { 29 mutable OwningPtr<BugType> BT; 30 31 public: 32 void checkPostStmt(const BlockExpr *BE, CheckerContext &C) const; 33 }; 34 } // end anonymous namespace 35 36 static const DeclRefExpr *FindBlockDeclRefExpr(const Stmt *S, 37 const VarDecl *VD) { 38 if (const DeclRefExpr *BR = dyn_cast<DeclRefExpr>(S)) 39 if (BR->getDecl() == VD) 40 return BR; 41 42 for (Stmt::const_child_iterator I = S->child_begin(), E = S->child_end(); 43 I!=E; ++I) 44 if (const Stmt *child = *I) { 45 const DeclRefExpr *BR = FindBlockDeclRefExpr(child, VD); 46 if (BR) 47 return BR; 48 } 49 50 return NULL; 51 } 52 53 void 54 UndefCapturedBlockVarChecker::checkPostStmt(const BlockExpr *BE, 55 CheckerContext &C) const { 56 if (!BE->getBlockDecl()->hasCaptures()) 57 return; 58 59 ProgramStateRef state = C.getState(); 60 const BlockDataRegion *R = 61 cast<BlockDataRegion>(state->getSVal(BE, 62 C.getLocationContext()).getAsRegion()); 63 64 BlockDataRegion::referenced_vars_iterator I = R->referenced_vars_begin(), 65 E = R->referenced_vars_end(); 66 67 for (; I != E; ++I) { 68 // This VarRegion is the region associated with the block; we need 69 // the one associated with the encompassing context. 70 const VarRegion *VR = *I; 71 const VarDecl *VD = VR->getDecl(); 72 73 if (VD->getAttr<BlocksAttr>() || !VD->hasLocalStorage()) 74 continue; 75 76 // Get the VarRegion associated with VD in the local stack frame. 77 const LocationContext *LC = C.getLocationContext(); 78 VR = C.getSValBuilder().getRegionManager().getVarRegion(VD, LC); 79 SVal VRVal = state->getSVal(VR); 80 81 if (VRVal.isUndef()) 82 if (ExplodedNode *N = C.generateSink()) { 83 if (!BT) 84 BT.reset(new BuiltinBug("uninitialized variable captured by block")); 85 86 // Generate a bug report. 87 SmallString<128> buf; 88 llvm::raw_svector_ostream os(buf); 89 90 os << "Variable '" << VD->getName() 91 << "' is uninitialized when captured by block"; 92 93 BugReport *R = new BugReport(*BT, os.str(), N); 94 if (const Expr *Ex = FindBlockDeclRefExpr(BE->getBody(), VD)) 95 R->addRange(Ex->getSourceRange()); 96 R->addVisitor(new FindLastStoreBRVisitor(VRVal, VR)); 97 // need location of block 98 C.EmitReport(R); 99 } 100 } 101 } 102 103 void ento::registerUndefCapturedBlockVarChecker(CheckerManager &mgr) { 104 mgr.registerChecker<UndefCapturedBlockVarChecker>(); 105 } 106
