contrib/llvm/tools/clang/lib/StaticAnalyzer/Checkers/UndefCapturedBlockVarChecker.cpp

   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   const GRState *state = C.getState();
  59   const BlockDataRegion *R =
  60     cast<BlockDataRegion>(state->getSVal(BE).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;
  69     const VarDecl *VD = VR->getDecl();
  70
  71     if (VD->getAttr<BlocksAttr>() || !VD->hasLocalStorage())
  72       continue;
  73
  74     // Get the VarRegion associated with VD in the local stack frame.
  75     const LocationContext *LC = C.getPredecessor()->getLocationContext();
  76     VR = C.getSValBuilder().getRegionManager().getVarRegion(VD, LC);
  77
  78     if (state->getSVal(VR).isUndef())
  79       if (ExplodedNode *N = C.generateSink()) {
  80         if (!BT)
  81           BT.reset(new BuiltinBug("uninitialized variable captured by block"));
  82
  83         // Generate a bug report.
  84         llvm::SmallString<128> buf;
  85         llvm::raw_svector_ostream os(buf);
  86
  87         os << "Variable '" << VD->getName()
  88            << "' is uninitialized when captured by block";
  89
  90         EnhancedBugReport *R = new EnhancedBugReport(*BT, os.str(), N);
  91         if (const Expr *Ex = FindBlockDeclRefExpr(BE->getBody(), VD))
  92           R->addRange(Ex->getSourceRange());
  93         R->addVisitorCreator(bugreporter::registerFindLastStore, VR);
  94         // need location of block
  95         C.EmitReport(R);
  96       }
  97   }
  98 }
  99
 100 void ento::registerUndefCapturedBlockVarChecker(CheckerManager &mgr) {
 101   mgr.registerChecker<UndefCapturedBlockVarChecker>();
 102 }