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