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