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      1 //===- Consumed.cpp --------------------------------------------*- 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 // A intra-procedural analysis for checking consumed properties.  This is based,
     11 // in part, on research on linear types.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #include "clang/AST/ASTContext.h"
     16 #include "clang/AST/Attr.h"
     17 #include "clang/AST/DeclCXX.h"
     18 #include "clang/AST/ExprCXX.h"
     19 #include "clang/AST/RecursiveASTVisitor.h"
     20 #include "clang/AST/StmtCXX.h"
     21 #include "clang/AST/StmtVisitor.h"
     22 #include "clang/AST/Type.h"
     23 #include "clang/Analysis/Analyses/Consumed.h"
     24 #include "clang/Analysis/Analyses/PostOrderCFGView.h"
     25 #include "clang/Analysis/AnalysisContext.h"
     26 #include "clang/Analysis/CFG.h"
     27 #include "clang/Basic/OperatorKinds.h"
     28 #include "clang/Basic/SourceLocation.h"
     29 #include "llvm/ADT/DenseMap.h"
     30 #include "llvm/ADT/SmallVector.h"
     31 #include "llvm/Support/Compiler.h"
     32 #include "llvm/Support/raw_ostream.h"
     33 #include <memory>
     34 
     35 // TODO: Adjust states of args to constructors in the same way that arguments to
     36 //       function calls are handled.
     37 // TODO: Use information from tests in for- and while-loop conditional.
     38 // TODO: Add notes about the actual and expected state for
     39 // TODO: Correctly identify unreachable blocks when chaining boolean operators.
     40 // TODO: Adjust the parser and AttributesList class to support lists of
     41 //       identifiers.
     42 // TODO: Warn about unreachable code.
     43 // TODO: Switch to using a bitmap to track unreachable blocks.
     44 // TODO: Handle variable definitions, e.g. bool valid = x.isValid();
     45 //       if (valid) ...; (Deferred)
     46 // TODO: Take notes on state transitions to provide better warning messages.
     47 //       (Deferred)
     48 // TODO: Test nested conditionals: A) Checking the same value multiple times,
     49 //       and 2) Checking different values. (Deferred)
     50 
     51 using namespace clang;
     52 using namespace consumed;
     53 
     54 // Key method definition
     55 ConsumedWarningsHandlerBase::~ConsumedWarningsHandlerBase() {}
     56 
     57 static SourceLocation getFirstStmtLoc(const CFGBlock *Block) {
     58   // Find the source location of the first statement in the block, if the block
     59   // is not empty.
     60   for (const auto &B : *Block)
     61     if (Optional<CFGStmt> CS = B.getAs<CFGStmt>())
     62       return CS->getStmt()->getLocStart();
     63 
     64   // Block is empty.
     65   // If we have one successor, return the first statement in that block
     66   if (Block->succ_size() == 1 && *Block->succ_begin())
     67     return getFirstStmtLoc(*Block->succ_begin());
     68 
     69   return SourceLocation();
     70 }
     71 
     72 static SourceLocation getLastStmtLoc(const CFGBlock *Block) {
     73   // Find the source location of the last statement in the block, if the block
     74   // is not empty.
     75   if (const Stmt *StmtNode = Block->getTerminator()) {
     76     return StmtNode->getLocStart();
     77   } else {
     78     for (CFGBlock::const_reverse_iterator BI = Block->rbegin(),
     79          BE = Block->rend(); BI != BE; ++BI) {
     80       if (Optional<CFGStmt> CS = BI->getAs<CFGStmt>())
     81         return CS->getStmt()->getLocStart();
     82     }
     83   }
     84 
     85   // If we have one successor, return the first statement in that block
     86   SourceLocation Loc;
     87   if (Block->succ_size() == 1 && *Block->succ_begin())
     88     Loc = getFirstStmtLoc(*Block->succ_begin());
     89   if (Loc.isValid())
     90     return Loc;
     91 
     92   // If we have one predecessor, return the last statement in that block
     93   if (Block->pred_size() == 1 && *Block->pred_begin())
     94     return getLastStmtLoc(*Block->pred_begin());
     95 
     96   return Loc;
     97 }
     98 
     99 static ConsumedState invertConsumedUnconsumed(ConsumedState State) {
    100   switch (State) {
    101   case CS_Unconsumed:
    102     return CS_Consumed;
    103   case CS_Consumed:
    104     return CS_Unconsumed;
    105   case CS_None:
    106     return CS_None;
    107   case CS_Unknown:
    108     return CS_Unknown;
    109   }
    110   llvm_unreachable("invalid enum");
    111 }
    112 
    113 static bool isCallableInState(const CallableWhenAttr *CWAttr,
    114                               ConsumedState State) {
    115 
    116   for (const auto &S : CWAttr->callableStates()) {
    117     ConsumedState MappedAttrState = CS_None;
    118 
    119     switch (S) {
    120     case CallableWhenAttr::Unknown:
    121       MappedAttrState = CS_Unknown;
    122       break;
    123 
    124     case CallableWhenAttr::Unconsumed:
    125       MappedAttrState = CS_Unconsumed;
    126       break;
    127 
    128     case CallableWhenAttr::Consumed:
    129       MappedAttrState = CS_Consumed;
    130       break;
    131     }
    132 
    133     if (MappedAttrState == State)
    134       return true;
    135   }
    136 
    137   return false;
    138 }
    139 
    140 
    141 static bool isConsumableType(const QualType &QT) {
    142   if (QT->isPointerType() || QT->isReferenceType())
    143     return false;
    144 
    145   if (const CXXRecordDecl *RD = QT->getAsCXXRecordDecl())
    146     return RD->hasAttr<ConsumableAttr>();
    147 
    148   return false;
    149 }
    150 
    151 static bool isAutoCastType(const QualType &QT) {
    152   if (QT->isPointerType() || QT->isReferenceType())
    153     return false;
    154 
    155   if (const CXXRecordDecl *RD = QT->getAsCXXRecordDecl())
    156     return RD->hasAttr<ConsumableAutoCastAttr>();
    157 
    158   return false;
    159 }
    160 
    161 static bool isSetOnReadPtrType(const QualType &QT) {
    162   if (const CXXRecordDecl *RD = QT->getPointeeCXXRecordDecl())
    163     return RD->hasAttr<ConsumableSetOnReadAttr>();
    164   return false;
    165 }
    166 
    167 
    168 static bool isKnownState(ConsumedState State) {
    169   switch (State) {
    170   case CS_Unconsumed:
    171   case CS_Consumed:
    172     return true;
    173   case CS_None:
    174   case CS_Unknown:
    175     return false;
    176   }
    177   llvm_unreachable("invalid enum");
    178 }
    179 
    180 static bool isRValueRef(QualType ParamType) {
    181   return ParamType->isRValueReferenceType();
    182 }
    183 
    184 static bool isTestingFunction(const FunctionDecl *FunDecl) {
    185   return FunDecl->hasAttr<TestTypestateAttr>();
    186 }
    187 
    188 static bool isPointerOrRef(QualType ParamType) {
    189   return ParamType->isPointerType() || ParamType->isReferenceType();
    190 }
    191 
    192 static ConsumedState mapConsumableAttrState(const QualType QT) {
    193   assert(isConsumableType(QT));
    194 
    195   const ConsumableAttr *CAttr =
    196       QT->getAsCXXRecordDecl()->getAttr<ConsumableAttr>();
    197 
    198   switch (CAttr->getDefaultState()) {
    199   case ConsumableAttr::Unknown:
    200     return CS_Unknown;
    201   case ConsumableAttr::Unconsumed:
    202     return CS_Unconsumed;
    203   case ConsumableAttr::Consumed:
    204     return CS_Consumed;
    205   }
    206   llvm_unreachable("invalid enum");
    207 }
    208 
    209 static ConsumedState
    210 mapParamTypestateAttrState(const ParamTypestateAttr *PTAttr) {
    211   switch (PTAttr->getParamState()) {
    212   case ParamTypestateAttr::Unknown:
    213     return CS_Unknown;
    214   case ParamTypestateAttr::Unconsumed:
    215     return CS_Unconsumed;
    216   case ParamTypestateAttr::Consumed:
    217     return CS_Consumed;
    218   }
    219   llvm_unreachable("invalid_enum");
    220 }
    221 
    222 static ConsumedState
    223 mapReturnTypestateAttrState(const ReturnTypestateAttr *RTSAttr) {
    224   switch (RTSAttr->getState()) {
    225   case ReturnTypestateAttr::Unknown:
    226     return CS_Unknown;
    227   case ReturnTypestateAttr::Unconsumed:
    228     return CS_Unconsumed;
    229   case ReturnTypestateAttr::Consumed:
    230     return CS_Consumed;
    231   }
    232   llvm_unreachable("invalid enum");
    233 }
    234 
    235 static ConsumedState mapSetTypestateAttrState(const SetTypestateAttr *STAttr) {
    236   switch (STAttr->getNewState()) {
    237   case SetTypestateAttr::Unknown:
    238     return CS_Unknown;
    239   case SetTypestateAttr::Unconsumed:
    240     return CS_Unconsumed;
    241   case SetTypestateAttr::Consumed:
    242     return CS_Consumed;
    243   }
    244   llvm_unreachable("invalid_enum");
    245 }
    246 
    247 static StringRef stateToString(ConsumedState State) {
    248   switch (State) {
    249   case consumed::CS_None:
    250     return "none";
    251 
    252   case consumed::CS_Unknown:
    253     return "unknown";
    254 
    255   case consumed::CS_Unconsumed:
    256     return "unconsumed";
    257 
    258   case consumed::CS_Consumed:
    259     return "consumed";
    260   }
    261   llvm_unreachable("invalid enum");
    262 }
    263 
    264 static ConsumedState testsFor(const FunctionDecl *FunDecl) {
    265   assert(isTestingFunction(FunDecl));
    266   switch (FunDecl->getAttr<TestTypestateAttr>()->getTestState()) {
    267   case TestTypestateAttr::Unconsumed:
    268     return CS_Unconsumed;
    269   case TestTypestateAttr::Consumed:
    270     return CS_Consumed;
    271   }
    272   llvm_unreachable("invalid enum");
    273 }
    274 
    275 namespace {
    276 struct VarTestResult {
    277   const VarDecl *Var;
    278   ConsumedState TestsFor;
    279 };
    280 } // end anonymous::VarTestResult
    281 
    282 namespace clang {
    283 namespace consumed {
    284 
    285 enum EffectiveOp {
    286   EO_And,
    287   EO_Or
    288 };
    289 
    290 class PropagationInfo {
    291   enum {
    292     IT_None,
    293     IT_State,
    294     IT_VarTest,
    295     IT_BinTest,
    296     IT_Var,
    297     IT_Tmp
    298   } InfoType;
    299 
    300   struct BinTestTy {
    301     const BinaryOperator *Source;
    302     EffectiveOp EOp;
    303     VarTestResult LTest;
    304     VarTestResult RTest;
    305   };
    306 
    307   union {
    308     ConsumedState State;
    309     VarTestResult VarTest;
    310     const VarDecl *Var;
    311     const CXXBindTemporaryExpr *Tmp;
    312     BinTestTy BinTest;
    313   };
    314 
    315 public:
    316   PropagationInfo() : InfoType(IT_None) {}
    317 
    318   PropagationInfo(const VarTestResult &VarTest)
    319     : InfoType(IT_VarTest), VarTest(VarTest) {}
    320 
    321   PropagationInfo(const VarDecl *Var, ConsumedState TestsFor)
    322     : InfoType(IT_VarTest) {
    323 
    324     VarTest.Var      = Var;
    325     VarTest.TestsFor = TestsFor;
    326   }
    327 
    328   PropagationInfo(const BinaryOperator *Source, EffectiveOp EOp,
    329                   const VarTestResult &LTest, const VarTestResult &RTest)
    330     : InfoType(IT_BinTest) {
    331 
    332     BinTest.Source  = Source;
    333     BinTest.EOp     = EOp;
    334     BinTest.LTest   = LTest;
    335     BinTest.RTest   = RTest;
    336   }
    337 
    338   PropagationInfo(const BinaryOperator *Source, EffectiveOp EOp,
    339                   const VarDecl *LVar, ConsumedState LTestsFor,
    340                   const VarDecl *RVar, ConsumedState RTestsFor)
    341     : InfoType(IT_BinTest) {
    342 
    343     BinTest.Source         = Source;
    344     BinTest.EOp            = EOp;
    345     BinTest.LTest.Var      = LVar;
    346     BinTest.LTest.TestsFor = LTestsFor;
    347     BinTest.RTest.Var      = RVar;
    348     BinTest.RTest.TestsFor = RTestsFor;
    349   }
    350 
    351   PropagationInfo(ConsumedState State)
    352     : InfoType(IT_State), State(State) {}
    353 
    354   PropagationInfo(const VarDecl *Var) : InfoType(IT_Var), Var(Var) {}
    355   PropagationInfo(const CXXBindTemporaryExpr *Tmp)
    356     : InfoType(IT_Tmp), Tmp(Tmp) {}
    357 
    358   const ConsumedState & getState() const {
    359     assert(InfoType == IT_State);
    360     return State;
    361   }
    362 
    363   const VarTestResult & getVarTest() const {
    364     assert(InfoType == IT_VarTest);
    365     return VarTest;
    366   }
    367 
    368   const VarTestResult & getLTest() const {
    369     assert(InfoType == IT_BinTest);
    370     return BinTest.LTest;
    371   }
    372 
    373   const VarTestResult & getRTest() const {
    374     assert(InfoType == IT_BinTest);
    375     return BinTest.RTest;
    376   }
    377 
    378   const VarDecl * getVar() const {
    379     assert(InfoType == IT_Var);
    380     return Var;
    381   }
    382 
    383   const CXXBindTemporaryExpr * getTmp() const {
    384     assert(InfoType == IT_Tmp);
    385     return Tmp;
    386   }
    387 
    388   ConsumedState getAsState(const ConsumedStateMap *StateMap) const {
    389     assert(isVar() || isTmp() || isState());
    390 
    391     if (isVar())
    392       return StateMap->getState(Var);
    393     else if (isTmp())
    394       return StateMap->getState(Tmp);
    395     else if (isState())
    396       return State;
    397     else
    398       return CS_None;
    399   }
    400 
    401   EffectiveOp testEffectiveOp() const {
    402     assert(InfoType == IT_BinTest);
    403     return BinTest.EOp;
    404   }
    405 
    406   const BinaryOperator * testSourceNode() const {
    407     assert(InfoType == IT_BinTest);
    408     return BinTest.Source;
    409   }
    410 
    411   inline bool isValid()   const { return InfoType != IT_None;    }
    412   inline bool isState()   const { return InfoType == IT_State;   }
    413   inline bool isVarTest() const { return InfoType == IT_VarTest; }
    414   inline bool isBinTest() const { return InfoType == IT_BinTest; }
    415   inline bool isVar()     const { return InfoType == IT_Var;     }
    416   inline bool isTmp()     const { return InfoType == IT_Tmp;     }
    417 
    418   bool isTest() const {
    419     return InfoType == IT_VarTest || InfoType == IT_BinTest;
    420   }
    421 
    422   bool isPointerToValue() const {
    423     return InfoType == IT_Var || InfoType == IT_Tmp;
    424   }
    425 
    426   PropagationInfo invertTest() const {
    427     assert(InfoType == IT_VarTest || InfoType == IT_BinTest);
    428 
    429     if (InfoType == IT_VarTest) {
    430       return PropagationInfo(VarTest.Var,
    431                              invertConsumedUnconsumed(VarTest.TestsFor));
    432 
    433     } else if (InfoType == IT_BinTest) {
    434       return PropagationInfo(BinTest.Source,
    435         BinTest.EOp == EO_And ? EO_Or : EO_And,
    436         BinTest.LTest.Var, invertConsumedUnconsumed(BinTest.LTest.TestsFor),
    437         BinTest.RTest.Var, invertConsumedUnconsumed(BinTest.RTest.TestsFor));
    438     } else {
    439       return PropagationInfo();
    440     }
    441   }
    442 };
    443 
    444 static inline void
    445 setStateForVarOrTmp(ConsumedStateMap *StateMap, const PropagationInfo &PInfo,
    446                     ConsumedState State) {
    447 
    448   assert(PInfo.isVar() || PInfo.isTmp());
    449 
    450   if (PInfo.isVar())
    451     StateMap->setState(PInfo.getVar(), State);
    452   else
    453     StateMap->setState(PInfo.getTmp(), State);
    454 }
    455 
    456 class ConsumedStmtVisitor : public ConstStmtVisitor<ConsumedStmtVisitor> {
    457 
    458   typedef llvm::DenseMap<const Stmt *, PropagationInfo> MapType;
    459   typedef std::pair<const Stmt *, PropagationInfo> PairType;
    460   typedef MapType::iterator InfoEntry;
    461   typedef MapType::const_iterator ConstInfoEntry;
    462 
    463   AnalysisDeclContext &AC;
    464   ConsumedAnalyzer &Analyzer;
    465   ConsumedStateMap *StateMap;
    466   MapType PropagationMap;
    467 
    468   InfoEntry findInfo(const Expr *E) {
    469     if (auto Cleanups = dyn_cast<ExprWithCleanups>(E))
    470       if (!Cleanups->cleanupsHaveSideEffects())
    471         E = Cleanups->getSubExpr();
    472     return PropagationMap.find(E->IgnoreParens());
    473   }
    474   ConstInfoEntry findInfo(const Expr *E) const {
    475     if (auto Cleanups = dyn_cast<ExprWithCleanups>(E))
    476       if (!Cleanups->cleanupsHaveSideEffects())
    477         E = Cleanups->getSubExpr();
    478     return PropagationMap.find(E->IgnoreParens());
    479   }
    480   void insertInfo(const Expr *E, const PropagationInfo &PI) {
    481     PropagationMap.insert(PairType(E->IgnoreParens(), PI));
    482   }
    483 
    484   void forwardInfo(const Expr *From, const Expr *To);
    485   void copyInfo(const Expr *From, const Expr *To, ConsumedState CS);
    486   ConsumedState getInfo(const Expr *From);
    487   void setInfo(const Expr *To, ConsumedState NS);
    488   void propagateReturnType(const Expr *Call, const FunctionDecl *Fun);
    489 
    490 public:
    491   void checkCallability(const PropagationInfo &PInfo,
    492                         const FunctionDecl *FunDecl,
    493                         SourceLocation BlameLoc);
    494   bool handleCall(const CallExpr *Call, const Expr *ObjArg,
    495                   const FunctionDecl *FunD);
    496 
    497   void VisitBinaryOperator(const BinaryOperator *BinOp);
    498   void VisitCallExpr(const CallExpr *Call);
    499   void VisitCastExpr(const CastExpr *Cast);
    500   void VisitCXXBindTemporaryExpr(const CXXBindTemporaryExpr *Temp);
    501   void VisitCXXConstructExpr(const CXXConstructExpr *Call);
    502   void VisitCXXMemberCallExpr(const CXXMemberCallExpr *Call);
    503   void VisitCXXOperatorCallExpr(const CXXOperatorCallExpr *Call);
    504   void VisitDeclRefExpr(const DeclRefExpr *DeclRef);
    505   void VisitDeclStmt(const DeclStmt *DelcS);
    506   void VisitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *Temp);
    507   void VisitMemberExpr(const MemberExpr *MExpr);
    508   void VisitParmVarDecl(const ParmVarDecl *Param);
    509   void VisitReturnStmt(const ReturnStmt *Ret);
    510   void VisitUnaryOperator(const UnaryOperator *UOp);
    511   void VisitVarDecl(const VarDecl *Var);
    512 
    513   ConsumedStmtVisitor(AnalysisDeclContext &AC, ConsumedAnalyzer &Analyzer,
    514                       ConsumedStateMap *StateMap)
    515       : AC(AC), Analyzer(Analyzer), StateMap(StateMap) {}
    516 
    517   PropagationInfo getInfo(const Expr *StmtNode) const {
    518     ConstInfoEntry Entry = findInfo(StmtNode);
    519 
    520     if (Entry != PropagationMap.end())
    521       return Entry->second;
    522     else
    523       return PropagationInfo();
    524   }
    525 
    526   void reset(ConsumedStateMap *NewStateMap) {
    527     StateMap = NewStateMap;
    528   }
    529 };
    530 
    531 
    532 void ConsumedStmtVisitor::forwardInfo(const Expr *From, const Expr *To) {
    533   InfoEntry Entry = findInfo(From);
    534   if (Entry != PropagationMap.end())
    535     insertInfo(To, Entry->second);
    536 }
    537 
    538 
    539 // Create a new state for To, which is initialized to the state of From.
    540 // If NS is not CS_None, sets the state of From to NS.
    541 void ConsumedStmtVisitor::copyInfo(const Expr *From, const Expr *To,
    542                                    ConsumedState NS) {
    543   InfoEntry Entry = findInfo(From);
    544   if (Entry != PropagationMap.end()) {
    545     PropagationInfo& PInfo = Entry->second;
    546     ConsumedState CS = PInfo.getAsState(StateMap);
    547     if (CS != CS_None)
    548       insertInfo(To, PropagationInfo(CS));
    549     if (NS != CS_None && PInfo.isPointerToValue())
    550       setStateForVarOrTmp(StateMap, PInfo, NS);
    551   }
    552 }
    553 
    554 
    555 // Get the ConsumedState for From
    556 ConsumedState ConsumedStmtVisitor::getInfo(const Expr *From) {
    557   InfoEntry Entry = findInfo(From);
    558   if (Entry != PropagationMap.end()) {
    559     PropagationInfo& PInfo = Entry->second;
    560     return PInfo.getAsState(StateMap);
    561   }
    562   return CS_None;
    563 }
    564 
    565 
    566 // If we already have info for To then update it, otherwise create a new entry.
    567 void ConsumedStmtVisitor::setInfo(const Expr *To, ConsumedState NS) {
    568   InfoEntry Entry = findInfo(To);
    569   if (Entry != PropagationMap.end()) {
    570     PropagationInfo& PInfo = Entry->second;
    571     if (PInfo.isPointerToValue())
    572       setStateForVarOrTmp(StateMap, PInfo, NS);
    573   } else if (NS != CS_None) {
    574      insertInfo(To, PropagationInfo(NS));
    575   }
    576 }
    577 
    578 
    579 
    580 void ConsumedStmtVisitor::checkCallability(const PropagationInfo &PInfo,
    581                                            const FunctionDecl *FunDecl,
    582                                            SourceLocation BlameLoc) {
    583   assert(!PInfo.isTest());
    584 
    585   const CallableWhenAttr *CWAttr = FunDecl->getAttr<CallableWhenAttr>();
    586   if (!CWAttr)
    587     return;
    588 
    589   if (PInfo.isVar()) {
    590     ConsumedState VarState = StateMap->getState(PInfo.getVar());
    591 
    592     if (VarState == CS_None || isCallableInState(CWAttr, VarState))
    593       return;
    594 
    595     Analyzer.WarningsHandler.warnUseInInvalidState(
    596       FunDecl->getNameAsString(), PInfo.getVar()->getNameAsString(),
    597       stateToString(VarState), BlameLoc);
    598 
    599   } else {
    600     ConsumedState TmpState = PInfo.getAsState(StateMap);
    601 
    602     if (TmpState == CS_None || isCallableInState(CWAttr, TmpState))
    603       return;
    604 
    605     Analyzer.WarningsHandler.warnUseOfTempInInvalidState(
    606       FunDecl->getNameAsString(), stateToString(TmpState), BlameLoc);
    607   }
    608 }
    609 
    610 
    611 // Factors out common behavior for function, method, and operator calls.
    612 // Check parameters and set parameter state if necessary.
    613 // Returns true if the state of ObjArg is set, or false otherwise.
    614 bool ConsumedStmtVisitor::handleCall(const CallExpr *Call, const Expr *ObjArg,
    615                                      const FunctionDecl *FunD) {
    616   unsigned Offset = 0;
    617   if (isa<CXXOperatorCallExpr>(Call) && isa<CXXMethodDecl>(FunD))
    618     Offset = 1;  // first argument is 'this'
    619 
    620   // check explicit parameters
    621   for (unsigned Index = Offset; Index < Call->getNumArgs(); ++Index) {
    622     // Skip variable argument lists.
    623     if (Index - Offset >= FunD->getNumParams())
    624       break;
    625 
    626     const ParmVarDecl *Param = FunD->getParamDecl(Index - Offset);
    627     QualType ParamType = Param->getType();
    628 
    629     InfoEntry Entry = findInfo(Call->getArg(Index));
    630 
    631     if (Entry == PropagationMap.end() || Entry->second.isTest())
    632       continue;
    633     PropagationInfo PInfo = Entry->second;
    634 
    635     // Check that the parameter is in the correct state.
    636     if (ParamTypestateAttr *PTA = Param->getAttr<ParamTypestateAttr>()) {
    637       ConsumedState ParamState = PInfo.getAsState(StateMap);
    638       ConsumedState ExpectedState = mapParamTypestateAttrState(PTA);
    639 
    640       if (ParamState != ExpectedState)
    641         Analyzer.WarningsHandler.warnParamTypestateMismatch(
    642           Call->getArg(Index)->getExprLoc(),
    643           stateToString(ExpectedState), stateToString(ParamState));
    644     }
    645 
    646     if (!(Entry->second.isVar() || Entry->second.isTmp()))
    647       continue;
    648 
    649     // Adjust state on the caller side.
    650     if (isRValueRef(ParamType))
    651       setStateForVarOrTmp(StateMap, PInfo, consumed::CS_Consumed);
    652     else if (ReturnTypestateAttr *RT = Param->getAttr<ReturnTypestateAttr>())
    653       setStateForVarOrTmp(StateMap, PInfo, mapReturnTypestateAttrState(RT));
    654     else if (isPointerOrRef(ParamType) &&
    655              (!ParamType->getPointeeType().isConstQualified() ||
    656               isSetOnReadPtrType(ParamType)))
    657       setStateForVarOrTmp(StateMap, PInfo, consumed::CS_Unknown);
    658   }
    659 
    660   if (!ObjArg)
    661     return false;
    662 
    663   // check implicit 'self' parameter, if present
    664   InfoEntry Entry = findInfo(ObjArg);
    665   if (Entry != PropagationMap.end()) {
    666     PropagationInfo PInfo = Entry->second;
    667     checkCallability(PInfo, FunD, Call->getExprLoc());
    668 
    669     if (SetTypestateAttr *STA = FunD->getAttr<SetTypestateAttr>()) {
    670       if (PInfo.isVar()) {
    671         StateMap->setState(PInfo.getVar(), mapSetTypestateAttrState(STA));
    672         return true;
    673       }
    674       else if (PInfo.isTmp()) {
    675         StateMap->setState(PInfo.getTmp(), mapSetTypestateAttrState(STA));
    676         return true;
    677       }
    678     }
    679     else if (isTestingFunction(FunD) && PInfo.isVar()) {
    680       PropagationMap.insert(PairType(Call,
    681         PropagationInfo(PInfo.getVar(), testsFor(FunD))));
    682     }
    683   }
    684   return false;
    685 }
    686 
    687 
    688 void ConsumedStmtVisitor::propagateReturnType(const Expr *Call,
    689                                               const FunctionDecl *Fun) {
    690   QualType RetType = Fun->getCallResultType();
    691   if (RetType->isReferenceType())
    692     RetType = RetType->getPointeeType();
    693 
    694   if (isConsumableType(RetType)) {
    695     ConsumedState ReturnState;
    696     if (ReturnTypestateAttr *RTA = Fun->getAttr<ReturnTypestateAttr>())
    697       ReturnState = mapReturnTypestateAttrState(RTA);
    698     else
    699       ReturnState = mapConsumableAttrState(RetType);
    700 
    701     PropagationMap.insert(PairType(Call, PropagationInfo(ReturnState)));
    702   }
    703 }
    704 
    705 
    706 void ConsumedStmtVisitor::VisitBinaryOperator(const BinaryOperator *BinOp) {
    707   switch (BinOp->getOpcode()) {
    708   case BO_LAnd:
    709   case BO_LOr : {
    710     InfoEntry LEntry = findInfo(BinOp->getLHS()),
    711               REntry = findInfo(BinOp->getRHS());
    712 
    713     VarTestResult LTest, RTest;
    714 
    715     if (LEntry != PropagationMap.end() && LEntry->second.isVarTest()) {
    716       LTest = LEntry->second.getVarTest();
    717 
    718     } else {
    719       LTest.Var      = nullptr;
    720       LTest.TestsFor = CS_None;
    721     }
    722 
    723     if (REntry != PropagationMap.end() && REntry->second.isVarTest()) {
    724       RTest = REntry->second.getVarTest();
    725 
    726     } else {
    727       RTest.Var      = nullptr;
    728       RTest.TestsFor = CS_None;
    729     }
    730 
    731     if (!(LTest.Var == nullptr && RTest.Var == nullptr))
    732       PropagationMap.insert(PairType(BinOp, PropagationInfo(BinOp,
    733         static_cast<EffectiveOp>(BinOp->getOpcode() == BO_LOr), LTest, RTest)));
    734 
    735     break;
    736   }
    737 
    738   case BO_PtrMemD:
    739   case BO_PtrMemI:
    740     forwardInfo(BinOp->getLHS(), BinOp);
    741     break;
    742 
    743   default:
    744     break;
    745   }
    746 }
    747 
    748 void ConsumedStmtVisitor::VisitCallExpr(const CallExpr *Call) {
    749   const FunctionDecl *FunDecl = Call->getDirectCallee();
    750   if (!FunDecl)
    751     return;
    752 
    753   // Special case for the std::move function.
    754   // TODO: Make this more specific. (Deferred)
    755   if (Call->getNumArgs() == 1 && FunDecl->getNameAsString() == "move" &&
    756       FunDecl->isInStdNamespace()) {
    757     copyInfo(Call->getArg(0), Call, CS_Consumed);
    758     return;
    759   }
    760 
    761   handleCall(Call, nullptr, FunDecl);
    762   propagateReturnType(Call, FunDecl);
    763 }
    764 
    765 void ConsumedStmtVisitor::VisitCastExpr(const CastExpr *Cast) {
    766   forwardInfo(Cast->getSubExpr(), Cast);
    767 }
    768 
    769 void ConsumedStmtVisitor::VisitCXXBindTemporaryExpr(
    770   const CXXBindTemporaryExpr *Temp) {
    771 
    772   InfoEntry Entry = findInfo(Temp->getSubExpr());
    773 
    774   if (Entry != PropagationMap.end() && !Entry->second.isTest()) {
    775     StateMap->setState(Temp, Entry->second.getAsState(StateMap));
    776     PropagationMap.insert(PairType(Temp, PropagationInfo(Temp)));
    777   }
    778 }
    779 
    780 void ConsumedStmtVisitor::VisitCXXConstructExpr(const CXXConstructExpr *Call) {
    781   CXXConstructorDecl *Constructor = Call->getConstructor();
    782 
    783   ASTContext &CurrContext = AC.getASTContext();
    784   QualType ThisType = Constructor->getThisType(CurrContext)->getPointeeType();
    785 
    786   if (!isConsumableType(ThisType))
    787     return;
    788 
    789   // FIXME: What should happen if someone annotates the move constructor?
    790   if (ReturnTypestateAttr *RTA = Constructor->getAttr<ReturnTypestateAttr>()) {
    791     // TODO: Adjust state of args appropriately.
    792     ConsumedState RetState = mapReturnTypestateAttrState(RTA);
    793     PropagationMap.insert(PairType(Call, PropagationInfo(RetState)));
    794   } else if (Constructor->isDefaultConstructor()) {
    795     PropagationMap.insert(PairType(Call,
    796       PropagationInfo(consumed::CS_Consumed)));
    797   } else if (Constructor->isMoveConstructor()) {
    798     copyInfo(Call->getArg(0), Call, CS_Consumed);
    799   } else if (Constructor->isCopyConstructor()) {
    800     // Copy state from arg.  If setStateOnRead then set arg to CS_Unknown.
    801     ConsumedState NS =
    802       isSetOnReadPtrType(Constructor->getThisType(CurrContext)) ?
    803       CS_Unknown : CS_None;
    804     copyInfo(Call->getArg(0), Call, NS);
    805   } else {
    806     // TODO: Adjust state of args appropriately.
    807     ConsumedState RetState = mapConsumableAttrState(ThisType);
    808     PropagationMap.insert(PairType(Call, PropagationInfo(RetState)));
    809   }
    810 }
    811 
    812 
    813 void ConsumedStmtVisitor::VisitCXXMemberCallExpr(
    814     const CXXMemberCallExpr *Call) {
    815   CXXMethodDecl* MD = Call->getMethodDecl();
    816   if (!MD)
    817     return;
    818 
    819   handleCall(Call, Call->getImplicitObjectArgument(), MD);
    820   propagateReturnType(Call, MD);
    821 }
    822 
    823 
    824 void ConsumedStmtVisitor::VisitCXXOperatorCallExpr(
    825     const CXXOperatorCallExpr *Call) {
    826 
    827   const FunctionDecl *FunDecl =
    828     dyn_cast_or_null<FunctionDecl>(Call->getDirectCallee());
    829   if (!FunDecl) return;
    830 
    831   if (Call->getOperator() == OO_Equal) {
    832     ConsumedState CS = getInfo(Call->getArg(1));
    833     if (!handleCall(Call, Call->getArg(0), FunDecl))
    834       setInfo(Call->getArg(0), CS);
    835     return;
    836   }
    837 
    838   if (const CXXMemberCallExpr *MCall = dyn_cast<CXXMemberCallExpr>(Call))
    839     handleCall(MCall, MCall->getImplicitObjectArgument(), FunDecl);
    840   else
    841     handleCall(Call, Call->getArg(0), FunDecl);
    842 
    843   propagateReturnType(Call, FunDecl);
    844 }
    845 
    846 void ConsumedStmtVisitor::VisitDeclRefExpr(const DeclRefExpr *DeclRef) {
    847   if (const VarDecl *Var = dyn_cast_or_null<VarDecl>(DeclRef->getDecl()))
    848     if (StateMap->getState(Var) != consumed::CS_None)
    849       PropagationMap.insert(PairType(DeclRef, PropagationInfo(Var)));
    850 }
    851 
    852 void ConsumedStmtVisitor::VisitDeclStmt(const DeclStmt *DeclS) {
    853   for (const auto *DI : DeclS->decls())
    854     if (isa<VarDecl>(DI))
    855       VisitVarDecl(cast<VarDecl>(DI));
    856 
    857   if (DeclS->isSingleDecl())
    858     if (const VarDecl *Var = dyn_cast_or_null<VarDecl>(DeclS->getSingleDecl()))
    859       PropagationMap.insert(PairType(DeclS, PropagationInfo(Var)));
    860 }
    861 
    862 void ConsumedStmtVisitor::VisitMaterializeTemporaryExpr(
    863   const MaterializeTemporaryExpr *Temp) {
    864 
    865   forwardInfo(Temp->GetTemporaryExpr(), Temp);
    866 }
    867 
    868 void ConsumedStmtVisitor::VisitMemberExpr(const MemberExpr *MExpr) {
    869   forwardInfo(MExpr->getBase(), MExpr);
    870 }
    871 
    872 
    873 void ConsumedStmtVisitor::VisitParmVarDecl(const ParmVarDecl *Param) {
    874   QualType ParamType = Param->getType();
    875   ConsumedState ParamState = consumed::CS_None;
    876 
    877   if (const ParamTypestateAttr *PTA = Param->getAttr<ParamTypestateAttr>())
    878     ParamState = mapParamTypestateAttrState(PTA);
    879   else if (isConsumableType(ParamType))
    880     ParamState = mapConsumableAttrState(ParamType);
    881   else if (isRValueRef(ParamType) &&
    882            isConsumableType(ParamType->getPointeeType()))
    883     ParamState = mapConsumableAttrState(ParamType->getPointeeType());
    884   else if (ParamType->isReferenceType() &&
    885            isConsumableType(ParamType->getPointeeType()))
    886     ParamState = consumed::CS_Unknown;
    887 
    888   if (ParamState != CS_None)
    889     StateMap->setState(Param, ParamState);
    890 }
    891 
    892 void ConsumedStmtVisitor::VisitReturnStmt(const ReturnStmt *Ret) {
    893   ConsumedState ExpectedState = Analyzer.getExpectedReturnState();
    894 
    895   if (ExpectedState != CS_None) {
    896     InfoEntry Entry = findInfo(Ret->getRetValue());
    897 
    898     if (Entry != PropagationMap.end()) {
    899       ConsumedState RetState = Entry->second.getAsState(StateMap);
    900 
    901       if (RetState != ExpectedState)
    902         Analyzer.WarningsHandler.warnReturnTypestateMismatch(
    903           Ret->getReturnLoc(), stateToString(ExpectedState),
    904           stateToString(RetState));
    905     }
    906   }
    907 
    908   StateMap->checkParamsForReturnTypestate(Ret->getLocStart(),
    909                                           Analyzer.WarningsHandler);
    910 }
    911 
    912 void ConsumedStmtVisitor::VisitUnaryOperator(const UnaryOperator *UOp) {
    913   InfoEntry Entry = findInfo(UOp->getSubExpr());
    914   if (Entry == PropagationMap.end()) return;
    915 
    916   switch (UOp->getOpcode()) {
    917   case UO_AddrOf:
    918     PropagationMap.insert(PairType(UOp, Entry->second));
    919     break;
    920 
    921   case UO_LNot:
    922     if (Entry->second.isTest())
    923       PropagationMap.insert(PairType(UOp, Entry->second.invertTest()));
    924     break;
    925 
    926   default:
    927     break;
    928   }
    929 }
    930 
    931 // TODO: See if I need to check for reference types here.
    932 void ConsumedStmtVisitor::VisitVarDecl(const VarDecl *Var) {
    933   if (isConsumableType(Var->getType())) {
    934     if (Var->hasInit()) {
    935       MapType::iterator VIT = findInfo(Var->getInit()->IgnoreImplicit());
    936       if (VIT != PropagationMap.end()) {
    937         PropagationInfo PInfo = VIT->second;
    938         ConsumedState St = PInfo.getAsState(StateMap);
    939 
    940         if (St != consumed::CS_None) {
    941           StateMap->setState(Var, St);
    942           return;
    943         }
    944       }
    945     }
    946     // Otherwise
    947     StateMap->setState(Var, consumed::CS_Unknown);
    948   }
    949 }
    950 }} // end clang::consumed::ConsumedStmtVisitor
    951 
    952 namespace clang {
    953 namespace consumed {
    954 
    955 static void splitVarStateForIf(const IfStmt *IfNode, const VarTestResult &Test,
    956                                ConsumedStateMap *ThenStates,
    957                                ConsumedStateMap *ElseStates) {
    958   ConsumedState VarState = ThenStates->getState(Test.Var);
    959 
    960   if (VarState == CS_Unknown) {
    961     ThenStates->setState(Test.Var, Test.TestsFor);
    962     ElseStates->setState(Test.Var, invertConsumedUnconsumed(Test.TestsFor));
    963 
    964   } else if (VarState == invertConsumedUnconsumed(Test.TestsFor)) {
    965     ThenStates->markUnreachable();
    966 
    967   } else if (VarState == Test.TestsFor) {
    968     ElseStates->markUnreachable();
    969   }
    970 }
    971 
    972 static void splitVarStateForIfBinOp(const PropagationInfo &PInfo,
    973                                     ConsumedStateMap *ThenStates,
    974                                     ConsumedStateMap *ElseStates) {
    975   const VarTestResult &LTest = PInfo.getLTest(),
    976                       &RTest = PInfo.getRTest();
    977 
    978   ConsumedState LState = LTest.Var ? ThenStates->getState(LTest.Var) : CS_None,
    979                 RState = RTest.Var ? ThenStates->getState(RTest.Var) : CS_None;
    980 
    981   if (LTest.Var) {
    982     if (PInfo.testEffectiveOp() == EO_And) {
    983       if (LState == CS_Unknown) {
    984         ThenStates->setState(LTest.Var, LTest.TestsFor);
    985 
    986       } else if (LState == invertConsumedUnconsumed(LTest.TestsFor)) {
    987         ThenStates->markUnreachable();
    988 
    989       } else if (LState == LTest.TestsFor && isKnownState(RState)) {
    990         if (RState == RTest.TestsFor)
    991           ElseStates->markUnreachable();
    992         else
    993           ThenStates->markUnreachable();
    994       }
    995 
    996     } else {
    997       if (LState == CS_Unknown) {
    998         ElseStates->setState(LTest.Var,
    999                              invertConsumedUnconsumed(LTest.TestsFor));
   1000 
   1001       } else if (LState == LTest.TestsFor) {
   1002         ElseStates->markUnreachable();
   1003 
   1004       } else if (LState == invertConsumedUnconsumed(LTest.TestsFor) &&
   1005                  isKnownState(RState)) {
   1006 
   1007         if (RState == RTest.TestsFor)
   1008           ElseStates->markUnreachable();
   1009         else
   1010           ThenStates->markUnreachable();
   1011       }
   1012     }
   1013   }
   1014 
   1015   if (RTest.Var) {
   1016     if (PInfo.testEffectiveOp() == EO_And) {
   1017       if (RState == CS_Unknown)
   1018         ThenStates->setState(RTest.Var, RTest.TestsFor);
   1019       else if (RState == invertConsumedUnconsumed(RTest.TestsFor))
   1020         ThenStates->markUnreachable();
   1021 
   1022     } else {
   1023       if (RState == CS_Unknown)
   1024         ElseStates->setState(RTest.Var,
   1025                              invertConsumedUnconsumed(RTest.TestsFor));
   1026       else if (RState == RTest.TestsFor)
   1027         ElseStates->markUnreachable();
   1028     }
   1029   }
   1030 }
   1031 
   1032 bool ConsumedBlockInfo::allBackEdgesVisited(const CFGBlock *CurrBlock,
   1033                                             const CFGBlock *TargetBlock) {
   1034 
   1035   assert(CurrBlock && "Block pointer must not be NULL");
   1036   assert(TargetBlock && "TargetBlock pointer must not be NULL");
   1037 
   1038   unsigned int CurrBlockOrder = VisitOrder[CurrBlock->getBlockID()];
   1039   for (CFGBlock::const_pred_iterator PI = TargetBlock->pred_begin(),
   1040        PE = TargetBlock->pred_end(); PI != PE; ++PI) {
   1041     if (*PI && CurrBlockOrder < VisitOrder[(*PI)->getBlockID()] )
   1042       return false;
   1043   }
   1044   return true;
   1045 }
   1046 
   1047 void ConsumedBlockInfo::addInfo(
   1048     const CFGBlock *Block, ConsumedStateMap *StateMap,
   1049     std::unique_ptr<ConsumedStateMap> &OwnedStateMap) {
   1050 
   1051   assert(Block && "Block pointer must not be NULL");
   1052 
   1053   auto &Entry = StateMapsArray[Block->getBlockID()];
   1054 
   1055   if (Entry) {
   1056     Entry->intersect(*StateMap);
   1057   } else if (OwnedStateMap)
   1058     Entry = std::move(OwnedStateMap);
   1059   else
   1060     Entry = llvm::make_unique<ConsumedStateMap>(*StateMap);
   1061 }
   1062 
   1063 void ConsumedBlockInfo::addInfo(const CFGBlock *Block,
   1064                                 std::unique_ptr<ConsumedStateMap> StateMap) {
   1065 
   1066   assert(Block && "Block pointer must not be NULL");
   1067 
   1068   auto &Entry = StateMapsArray[Block->getBlockID()];
   1069 
   1070   if (Entry) {
   1071     Entry->intersect(*StateMap);
   1072   } else {
   1073     Entry = std::move(StateMap);
   1074   }
   1075 }
   1076 
   1077 ConsumedStateMap* ConsumedBlockInfo::borrowInfo(const CFGBlock *Block) {
   1078   assert(Block && "Block pointer must not be NULL");
   1079   assert(StateMapsArray[Block->getBlockID()] && "Block has no block info");
   1080 
   1081   return StateMapsArray[Block->getBlockID()].get();
   1082 }
   1083 
   1084 void ConsumedBlockInfo::discardInfo(const CFGBlock *Block) {
   1085   StateMapsArray[Block->getBlockID()] = nullptr;
   1086 }
   1087 
   1088 std::unique_ptr<ConsumedStateMap>
   1089 ConsumedBlockInfo::getInfo(const CFGBlock *Block) {
   1090   assert(Block && "Block pointer must not be NULL");
   1091 
   1092   auto &Entry = StateMapsArray[Block->getBlockID()];
   1093   return isBackEdgeTarget(Block) ? llvm::make_unique<ConsumedStateMap>(*Entry)
   1094                                  : std::move(Entry);
   1095 }
   1096 
   1097 bool ConsumedBlockInfo::isBackEdge(const CFGBlock *From, const CFGBlock *To) {
   1098   assert(From && "From block must not be NULL");
   1099   assert(To   && "From block must not be NULL");
   1100 
   1101   return VisitOrder[From->getBlockID()] > VisitOrder[To->getBlockID()];
   1102 }
   1103 
   1104 bool ConsumedBlockInfo::isBackEdgeTarget(const CFGBlock *Block) {
   1105   assert(Block && "Block pointer must not be NULL");
   1106 
   1107   // Anything with less than two predecessors can't be the target of a back
   1108   // edge.
   1109   if (Block->pred_size() < 2)
   1110     return false;
   1111 
   1112   unsigned int BlockVisitOrder = VisitOrder[Block->getBlockID()];
   1113   for (CFGBlock::const_pred_iterator PI = Block->pred_begin(),
   1114        PE = Block->pred_end(); PI != PE; ++PI) {
   1115     if (*PI && BlockVisitOrder < VisitOrder[(*PI)->getBlockID()])
   1116       return true;
   1117   }
   1118   return false;
   1119 }
   1120 
   1121 void ConsumedStateMap::checkParamsForReturnTypestate(SourceLocation BlameLoc,
   1122   ConsumedWarningsHandlerBase &WarningsHandler) const {
   1123 
   1124   for (const auto &DM : VarMap) {
   1125     if (isa<ParmVarDecl>(DM.first)) {
   1126       const ParmVarDecl *Param = cast<ParmVarDecl>(DM.first);
   1127       const ReturnTypestateAttr *RTA = Param->getAttr<ReturnTypestateAttr>();
   1128 
   1129       if (!RTA)
   1130         continue;
   1131 
   1132       ConsumedState ExpectedState = mapReturnTypestateAttrState(RTA);
   1133       if (DM.second != ExpectedState)
   1134         WarningsHandler.warnParamReturnTypestateMismatch(BlameLoc,
   1135           Param->getNameAsString(), stateToString(ExpectedState),
   1136           stateToString(DM.second));
   1137     }
   1138   }
   1139 }
   1140 
   1141 void ConsumedStateMap::clearTemporaries() {
   1142   TmpMap.clear();
   1143 }
   1144 
   1145 ConsumedState ConsumedStateMap::getState(const VarDecl *Var) const {
   1146   VarMapType::const_iterator Entry = VarMap.find(Var);
   1147 
   1148   if (Entry != VarMap.end())
   1149     return Entry->second;
   1150 
   1151   return CS_None;
   1152 }
   1153 
   1154 ConsumedState
   1155 ConsumedStateMap::getState(const CXXBindTemporaryExpr *Tmp) const {
   1156   TmpMapType::const_iterator Entry = TmpMap.find(Tmp);
   1157 
   1158   if (Entry != TmpMap.end())
   1159     return Entry->second;
   1160 
   1161   return CS_None;
   1162 }
   1163 
   1164 void ConsumedStateMap::intersect(const ConsumedStateMap &Other) {
   1165   ConsumedState LocalState;
   1166 
   1167   if (this->From && this->From == Other.From && !Other.Reachable) {
   1168     this->markUnreachable();
   1169     return;
   1170   }
   1171 
   1172   for (const auto &DM : Other.VarMap) {
   1173     LocalState = this->getState(DM.first);
   1174 
   1175     if (LocalState == CS_None)
   1176       continue;
   1177 
   1178     if (LocalState != DM.second)
   1179      VarMap[DM.first] = CS_Unknown;
   1180   }
   1181 }
   1182 
   1183 void ConsumedStateMap::intersectAtLoopHead(const CFGBlock *LoopHead,
   1184   const CFGBlock *LoopBack, const ConsumedStateMap *LoopBackStates,
   1185   ConsumedWarningsHandlerBase &WarningsHandler) {
   1186 
   1187   ConsumedState LocalState;
   1188   SourceLocation BlameLoc = getLastStmtLoc(LoopBack);
   1189 
   1190   for (const auto &DM : LoopBackStates->VarMap) {
   1191     LocalState = this->getState(DM.first);
   1192 
   1193     if (LocalState == CS_None)
   1194       continue;
   1195 
   1196     if (LocalState != DM.second) {
   1197       VarMap[DM.first] = CS_Unknown;
   1198       WarningsHandler.warnLoopStateMismatch(BlameLoc,
   1199                                             DM.first->getNameAsString());
   1200     }
   1201   }
   1202 }
   1203 
   1204 void ConsumedStateMap::markUnreachable() {
   1205   this->Reachable = false;
   1206   VarMap.clear();
   1207   TmpMap.clear();
   1208 }
   1209 
   1210 void ConsumedStateMap::setState(const VarDecl *Var, ConsumedState State) {
   1211   VarMap[Var] = State;
   1212 }
   1213 
   1214 void ConsumedStateMap::setState(const CXXBindTemporaryExpr *Tmp,
   1215                                 ConsumedState State) {
   1216   TmpMap[Tmp] = State;
   1217 }
   1218 
   1219 void ConsumedStateMap::remove(const CXXBindTemporaryExpr *Tmp) {
   1220   TmpMap.erase(Tmp);
   1221 }
   1222 
   1223 bool ConsumedStateMap::operator!=(const ConsumedStateMap *Other) const {
   1224   for (const auto &DM : Other->VarMap)
   1225     if (this->getState(DM.first) != DM.second)
   1226       return true;
   1227   return false;
   1228 }
   1229 
   1230 void ConsumedAnalyzer::determineExpectedReturnState(AnalysisDeclContext &AC,
   1231                                                     const FunctionDecl *D) {
   1232   QualType ReturnType;
   1233   if (const CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(D)) {
   1234     ASTContext &CurrContext = AC.getASTContext();
   1235     ReturnType = Constructor->getThisType(CurrContext)->getPointeeType();
   1236   } else
   1237     ReturnType = D->getCallResultType();
   1238 
   1239   if (const ReturnTypestateAttr *RTSAttr = D->getAttr<ReturnTypestateAttr>()) {
   1240     const CXXRecordDecl *RD = ReturnType->getAsCXXRecordDecl();
   1241     if (!RD || !RD->hasAttr<ConsumableAttr>()) {
   1242       // FIXME: This should be removed when template instantiation propagates
   1243       //        attributes at template specialization definition, not
   1244       //        declaration. When it is removed the test needs to be enabled
   1245       //        in SemaDeclAttr.cpp.
   1246       WarningsHandler.warnReturnTypestateForUnconsumableType(
   1247           RTSAttr->getLocation(), ReturnType.getAsString());
   1248       ExpectedReturnState = CS_None;
   1249     } else
   1250       ExpectedReturnState = mapReturnTypestateAttrState(RTSAttr);
   1251   } else if (isConsumableType(ReturnType)) {
   1252     if (isAutoCastType(ReturnType))   // We can auto-cast the state to the
   1253       ExpectedReturnState = CS_None;  // expected state.
   1254     else
   1255       ExpectedReturnState = mapConsumableAttrState(ReturnType);
   1256   }
   1257   else
   1258     ExpectedReturnState = CS_None;
   1259 }
   1260 
   1261 bool ConsumedAnalyzer::splitState(const CFGBlock *CurrBlock,
   1262                                   const ConsumedStmtVisitor &Visitor) {
   1263 
   1264   std::unique_ptr<ConsumedStateMap> FalseStates(
   1265       new ConsumedStateMap(*CurrStates));
   1266   PropagationInfo PInfo;
   1267 
   1268   if (const IfStmt *IfNode =
   1269     dyn_cast_or_null<IfStmt>(CurrBlock->getTerminator().getStmt())) {
   1270 
   1271     const Expr *Cond = IfNode->getCond();
   1272 
   1273     PInfo = Visitor.getInfo(Cond);
   1274     if (!PInfo.isValid() && isa<BinaryOperator>(Cond))
   1275       PInfo = Visitor.getInfo(cast<BinaryOperator>(Cond)->getRHS());
   1276 
   1277     if (PInfo.isVarTest()) {
   1278       CurrStates->setSource(Cond);
   1279       FalseStates->setSource(Cond);
   1280       splitVarStateForIf(IfNode, PInfo.getVarTest(), CurrStates.get(),
   1281                          FalseStates.get());
   1282 
   1283     } else if (PInfo.isBinTest()) {
   1284       CurrStates->setSource(PInfo.testSourceNode());
   1285       FalseStates->setSource(PInfo.testSourceNode());
   1286       splitVarStateForIfBinOp(PInfo, CurrStates.get(), FalseStates.get());
   1287 
   1288     } else {
   1289       return false;
   1290     }
   1291 
   1292   } else if (const BinaryOperator *BinOp =
   1293     dyn_cast_or_null<BinaryOperator>(CurrBlock->getTerminator().getStmt())) {
   1294 
   1295     PInfo = Visitor.getInfo(BinOp->getLHS());
   1296     if (!PInfo.isVarTest()) {
   1297       if ((BinOp = dyn_cast_or_null<BinaryOperator>(BinOp->getLHS()))) {
   1298         PInfo = Visitor.getInfo(BinOp->getRHS());
   1299 
   1300         if (!PInfo.isVarTest())
   1301           return false;
   1302 
   1303       } else {
   1304         return false;
   1305       }
   1306     }
   1307 
   1308     CurrStates->setSource(BinOp);
   1309     FalseStates->setSource(BinOp);
   1310 
   1311     const VarTestResult &Test = PInfo.getVarTest();
   1312     ConsumedState VarState = CurrStates->getState(Test.Var);
   1313 
   1314     if (BinOp->getOpcode() == BO_LAnd) {
   1315       if (VarState == CS_Unknown)
   1316         CurrStates->setState(Test.Var, Test.TestsFor);
   1317       else if (VarState == invertConsumedUnconsumed(Test.TestsFor))
   1318         CurrStates->markUnreachable();
   1319 
   1320     } else if (BinOp->getOpcode() == BO_LOr) {
   1321       if (VarState == CS_Unknown)
   1322         FalseStates->setState(Test.Var,
   1323                               invertConsumedUnconsumed(Test.TestsFor));
   1324       else if (VarState == Test.TestsFor)
   1325         FalseStates->markUnreachable();
   1326     }
   1327 
   1328   } else {
   1329     return false;
   1330   }
   1331 
   1332   CFGBlock::const_succ_iterator SI = CurrBlock->succ_begin();
   1333 
   1334   if (*SI)
   1335     BlockInfo.addInfo(*SI, std::move(CurrStates));
   1336   else
   1337     CurrStates = nullptr;
   1338 
   1339   if (*++SI)
   1340     BlockInfo.addInfo(*SI, std::move(FalseStates));
   1341 
   1342   return true;
   1343 }
   1344 
   1345 void ConsumedAnalyzer::run(AnalysisDeclContext &AC) {
   1346   const FunctionDecl *D = dyn_cast_or_null<FunctionDecl>(AC.getDecl());
   1347   if (!D)
   1348     return;
   1349 
   1350   CFG *CFGraph = AC.getCFG();
   1351   if (!CFGraph)
   1352     return;
   1353 
   1354   determineExpectedReturnState(AC, D);
   1355 
   1356   PostOrderCFGView *SortedGraph = AC.getAnalysis<PostOrderCFGView>();
   1357   // AC.getCFG()->viewCFG(LangOptions());
   1358 
   1359   BlockInfo = ConsumedBlockInfo(CFGraph->getNumBlockIDs(), SortedGraph);
   1360 
   1361   CurrStates = llvm::make_unique<ConsumedStateMap>();
   1362   ConsumedStmtVisitor Visitor(AC, *this, CurrStates.get());
   1363 
   1364   // Add all trackable parameters to the state map.
   1365   for (const auto *PI : D->parameters())
   1366     Visitor.VisitParmVarDecl(PI);
   1367 
   1368   // Visit all of the function's basic blocks.
   1369   for (const auto *CurrBlock : *SortedGraph) {
   1370     if (!CurrStates)
   1371       CurrStates = BlockInfo.getInfo(CurrBlock);
   1372 
   1373     if (!CurrStates) {
   1374       continue;
   1375 
   1376     } else if (!CurrStates->isReachable()) {
   1377       CurrStates = nullptr;
   1378       continue;
   1379     }
   1380 
   1381     Visitor.reset(CurrStates.get());
   1382 
   1383     // Visit all of the basic block's statements.
   1384     for (const auto &B : *CurrBlock) {
   1385       switch (B.getKind()) {
   1386       case CFGElement::Statement:
   1387         Visitor.Visit(B.castAs<CFGStmt>().getStmt());
   1388         break;
   1389 
   1390       case CFGElement::TemporaryDtor: {
   1391         const CFGTemporaryDtor &DTor = B.castAs<CFGTemporaryDtor>();
   1392         const CXXBindTemporaryExpr *BTE = DTor.getBindTemporaryExpr();
   1393 
   1394         Visitor.checkCallability(PropagationInfo(BTE),
   1395                                  DTor.getDestructorDecl(AC.getASTContext()),
   1396                                  BTE->getExprLoc());
   1397         CurrStates->remove(BTE);
   1398         break;
   1399       }
   1400 
   1401       case CFGElement::AutomaticObjectDtor: {
   1402         const CFGAutomaticObjDtor &DTor = B.castAs<CFGAutomaticObjDtor>();
   1403         SourceLocation Loc = DTor.getTriggerStmt()->getLocEnd();
   1404         const VarDecl *Var = DTor.getVarDecl();
   1405 
   1406         Visitor.checkCallability(PropagationInfo(Var),
   1407                                  DTor.getDestructorDecl(AC.getASTContext()),
   1408                                  Loc);
   1409         break;
   1410       }
   1411 
   1412       default:
   1413         break;
   1414       }
   1415     }
   1416 
   1417     // TODO: Handle other forms of branching with precision, including while-
   1418     //       and for-loops. (Deferred)
   1419     if (!splitState(CurrBlock, Visitor)) {
   1420       CurrStates->setSource(nullptr);
   1421 
   1422       if (CurrBlock->succ_size() > 1 ||
   1423           (CurrBlock->succ_size() == 1 &&
   1424            (*CurrBlock->succ_begin())->pred_size() > 1)) {
   1425 
   1426         auto *RawState = CurrStates.get();
   1427 
   1428         for (CFGBlock::const_succ_iterator SI = CurrBlock->succ_begin(),
   1429              SE = CurrBlock->succ_end(); SI != SE; ++SI) {
   1430 
   1431           if (*SI == nullptr) continue;
   1432 
   1433           if (BlockInfo.isBackEdge(CurrBlock, *SI)) {
   1434             BlockInfo.borrowInfo(*SI)->intersectAtLoopHead(
   1435                 *SI, CurrBlock, RawState, WarningsHandler);
   1436 
   1437             if (BlockInfo.allBackEdgesVisited(CurrBlock, *SI))
   1438               BlockInfo.discardInfo(*SI);
   1439           } else {
   1440             BlockInfo.addInfo(*SI, RawState, CurrStates);
   1441           }
   1442         }
   1443 
   1444         CurrStates = nullptr;
   1445       }
   1446     }
   1447 
   1448     if (CurrBlock == &AC.getCFG()->getExit() &&
   1449         D->getCallResultType()->isVoidType())
   1450       CurrStates->checkParamsForReturnTypestate(D->getLocation(),
   1451                                                 WarningsHandler);
   1452   } // End of block iterator.
   1453 
   1454   // Delete the last existing state map.
   1455   CurrStates = nullptr;
   1456 
   1457   WarningsHandler.emitDiagnostics();
   1458 }
   1459 }} // end namespace clang::consumed
   1460