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- //===- ThreadSafety.cpp ----------------------------------------*- C++ --*-===//
- //
- // The LLVM Compiler Infrastructure
- //
- // This file is distributed under the University of Illinois Open Source
- // License. See LICENSE.TXT for details.
- //
- //===----------------------------------------------------------------------===//
- //
- // A intra-procedural analysis for thread safety (e.g. deadlocks and race
- // conditions), based off of an annotation system.
- //
- // See http://clang.llvm.org/docs/LanguageExtensions.html#threadsafety for more
- // information.
- //
- //===----------------------------------------------------------------------===//
- #include "clang/Analysis/Analyses/ThreadSafety.h"
- #include "clang/Analysis/Analyses/PostOrderCFGView.h"
- #include "clang/Analysis/AnalysisContext.h"
- #include "clang/Analysis/CFG.h"
- #include "clang/Analysis/CFGStmtMap.h"
- #include "clang/AST/DeclCXX.h"
- #include "clang/AST/ExprCXX.h"
- #include "clang/AST/StmtCXX.h"
- #include "clang/AST/StmtVisitor.h"
- #include "clang/Basic/SourceManager.h"
- #include "clang/Basic/SourceLocation.h"
- #include "llvm/ADT/BitVector.h"
- #include "llvm/ADT/FoldingSet.h"
- #include "llvm/ADT/ImmutableMap.h"
- #include "llvm/ADT/PostOrderIterator.h"
- #include "llvm/ADT/SmallVector.h"
- #include "llvm/ADT/StringRef.h"
- #include "llvm/Support/raw_ostream.h"
- #include <algorithm>
- #include <utility>
- #include <vector>
- using namespace clang;
- using namespace thread_safety;
- // Key method definition
- ThreadSafetyHandler::~ThreadSafetyHandler() {}
- namespace {
- /// \brief A MutexID object uniquely identifies a particular mutex, and
- /// is built from an Expr* (i.e. calling a lock function).
- ///
- /// Thread-safety analysis works by comparing lock expressions. Within the
- /// body of a function, an expression such as "x->foo->bar.mu" will resolve to
- /// a particular mutex object at run-time. Subsequent occurrences of the same
- /// expression (where "same" means syntactic equality) will refer to the same
- /// run-time object if three conditions hold:
- /// (1) Local variables in the expression, such as "x" have not changed.
- /// (2) Values on the heap that affect the expression have not changed.
- /// (3) The expression involves only pure function calls.
- ///
- /// The current implementation assumes, but does not verify, that multiple uses
- /// of the same lock expression satisfies these criteria.
- ///
- /// Clang introduces an additional wrinkle, which is that it is difficult to
- /// derive canonical expressions, or compare expressions directly for equality.
- /// Thus, we identify a mutex not by an Expr, but by the list of named
- /// declarations that are referenced by the Expr. In other words,
- /// x->foo->bar.mu will be a four element vector with the Decls for
- /// mu, bar, and foo, and x. The vector will uniquely identify the expression
- /// for all practical purposes. Null is used to denote 'this'.
- ///
- /// Note we will need to perform substitution on "this" and function parameter
- /// names when constructing a lock expression.
- ///
- /// For example:
- /// class C { Mutex Mu; void lock() EXCLUSIVE_LOCK_FUNCTION(this->Mu); };
- /// void myFunc(C *X) { ... X->lock() ... }
- /// The original expression for the mutex acquired by myFunc is "this->Mu", but
- /// "X" is substituted for "this" so we get X->Mu();
- ///
- /// For another example:
- /// foo(MyList *L) EXCLUSIVE_LOCKS_REQUIRED(L->Mu) { ... }
- /// MyList *MyL;
- /// foo(MyL); // requires lock MyL->Mu to be held
- class MutexID {
- SmallVector<NamedDecl*, 2> DeclSeq;
- /// \brief Encapsulates the lexical context of a function call. The lexical
- /// context includes the arguments to the call, including the implicit object
- /// argument. When an attribute containing a mutex expression is attached to
- /// a method, the expression may refer to formal parameters of the method.
- /// Actual arguments must be substituted for formal parameters to derive
- /// the appropriate mutex expression in the lexical context where the function
- /// is called. PrevCtx holds the context in which the arguments themselves
- /// should be evaluated; multiple calling contexts can be chained together
- /// by the lock_returned attribute.
- struct CallingContext {
- const NamedDecl* AttrDecl; // The decl to which the attribute is attached.
- Expr* SelfArg; // Implicit object argument -- e.g. 'this'
- unsigned NumArgs; // Number of funArgs
- Expr** FunArgs; // Function arguments
- CallingContext* PrevCtx; // The previous context; or 0 if none.
- CallingContext(const NamedDecl* D = 0, Expr* S = 0,
- unsigned N = 0, Expr** A = 0, CallingContext* P = 0)
- : AttrDecl(D), SelfArg(S), NumArgs(N), FunArgs(A), PrevCtx(P)
- { }
- };
- /// Build a Decl sequence representing the lock from the given expression.
- /// Recursive function that terminates on DeclRefExpr.
- /// Note: this function merely creates a MutexID; it does not check to
- /// ensure that the original expression is a valid mutex expression.
- void buildMutexID(Expr *Exp, CallingContext* CallCtx) {
- if (!Exp) {
- DeclSeq.clear();
- return;
- }
- if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Exp)) {
- NamedDecl *ND = cast<NamedDecl>(DRE->getDecl()->getCanonicalDecl());
- ParmVarDecl *PV = dyn_cast_or_null<ParmVarDecl>(ND);
- if (PV) {
- FunctionDecl *FD =
- cast<FunctionDecl>(PV->getDeclContext())->getCanonicalDecl();
- unsigned i = PV->getFunctionScopeIndex();
- if (CallCtx && CallCtx->FunArgs &&
- FD == CallCtx->AttrDecl->getCanonicalDecl()) {
- // Substitute call arguments for references to function parameters
- assert(i < CallCtx->NumArgs);
- buildMutexID(CallCtx->FunArgs[i], CallCtx->PrevCtx);
- return;
- }
- // Map the param back to the param of the original function declaration.
- DeclSeq.push_back(FD->getParamDecl(i));
- return;
- }
- // Not a function parameter -- just store the reference.
- DeclSeq.push_back(ND);
- } else if (isa<CXXThisExpr>(Exp)) {
- // Substitute parent for 'this'
- if (CallCtx && CallCtx->SelfArg)
- buildMutexID(CallCtx->SelfArg, CallCtx->PrevCtx);
- else {
- DeclSeq.push_back(0); // Use 0 to represent 'this'.
- return; // mutexID is still valid in this case
- }
- } else if (MemberExpr *ME = dyn_cast<MemberExpr>(Exp)) {
- NamedDecl *ND = ME->getMemberDecl();
- DeclSeq.push_back(ND);
- buildMutexID(ME->getBase(), CallCtx);
- } else if (CXXMemberCallExpr *CMCE = dyn_cast<CXXMemberCallExpr>(Exp)) {
- // When calling a function with a lock_returned attribute, replace
- // the function call with the expression in lock_returned.
- if (LockReturnedAttr* At =
- CMCE->getMethodDecl()->getAttr<LockReturnedAttr>()) {
- CallingContext LRCallCtx(CMCE->getMethodDecl());
- LRCallCtx.SelfArg = CMCE->getImplicitObjectArgument();
- LRCallCtx.NumArgs = CMCE->getNumArgs();
- LRCallCtx.FunArgs = CMCE->getArgs();
- LRCallCtx.PrevCtx = CallCtx;
- buildMutexID(At->getArg(), &LRCallCtx);
- return;
- }
- DeclSeq.push_back(CMCE->getMethodDecl()->getCanonicalDecl());
- buildMutexID(CMCE->getImplicitObjectArgument(), CallCtx);
- unsigned NumCallArgs = CMCE->getNumArgs();
- Expr** CallArgs = CMCE->getArgs();
- for (unsigned i = 0; i < NumCallArgs; ++i) {
- buildMutexID(CallArgs[i], CallCtx);
- }
- } else if (CallExpr *CE = dyn_cast<CallExpr>(Exp)) {
- if (LockReturnedAttr* At =
- CE->getDirectCallee()->getAttr<LockReturnedAttr>()) {
- CallingContext LRCallCtx(CE->getDirectCallee());
- LRCallCtx.NumArgs = CE->getNumArgs();
- LRCallCtx.FunArgs = CE->getArgs();
- LRCallCtx.PrevCtx = CallCtx;
- buildMutexID(At->getArg(), &LRCallCtx);
- return;
- }
- buildMutexID(CE->getCallee(), CallCtx);
- unsigned NumCallArgs = CE->getNumArgs();
- Expr** CallArgs = CE->getArgs();
- for (unsigned i = 0; i < NumCallArgs; ++i) {
- buildMutexID(CallArgs[i], CallCtx);
- }
- } else if (BinaryOperator *BOE = dyn_cast<BinaryOperator>(Exp)) {
- buildMutexID(BOE->getLHS(), CallCtx);
- buildMutexID(BOE->getRHS(), CallCtx);
- } else if (UnaryOperator *UOE = dyn_cast<UnaryOperator>(Exp)) {
- buildMutexID(UOE->getSubExpr(), CallCtx);
- } else if (ArraySubscriptExpr *ASE = dyn_cast<ArraySubscriptExpr>(Exp)) {
- buildMutexID(ASE->getBase(), CallCtx);
- buildMutexID(ASE->getIdx(), CallCtx);
- } else if (AbstractConditionalOperator *CE =
- dyn_cast<AbstractConditionalOperator>(Exp)) {
- buildMutexID(CE->getCond(), CallCtx);
- buildMutexID(CE->getTrueExpr(), CallCtx);
- buildMutexID(CE->getFalseExpr(), CallCtx);
- } else if (ChooseExpr *CE = dyn_cast<ChooseExpr>(Exp)) {
- buildMutexID(CE->getCond(), CallCtx);
- buildMutexID(CE->getLHS(), CallCtx);
- buildMutexID(CE->getRHS(), CallCtx);
- } else if (CastExpr *CE = dyn_cast<CastExpr>(Exp)) {
- buildMutexID(CE->getSubExpr(), CallCtx);
- } else if (ParenExpr *PE = dyn_cast<ParenExpr>(Exp)) {
- buildMutexID(PE->getSubExpr(), CallCtx);
- } else if (isa<CharacterLiteral>(Exp) ||
- isa<CXXNullPtrLiteralExpr>(Exp) ||
- isa<GNUNullExpr>(Exp) ||
- isa<CXXBoolLiteralExpr>(Exp) ||
- isa<FloatingLiteral>(Exp) ||
- isa<ImaginaryLiteral>(Exp) ||
- isa<IntegerLiteral>(Exp) ||
- isa<StringLiteral>(Exp) ||
- isa<ObjCStringLiteral>(Exp)) {
- return; // FIXME: Ignore literals for now
- } else {
- // Ignore. FIXME: mark as invalid expression?
- }
- }
- /// \brief Construct a MutexID from an expression.
- /// \param MutexExp The original mutex expression within an attribute
- /// \param DeclExp An expression involving the Decl on which the attribute
- /// occurs.
- /// \param D The declaration to which the lock/unlock attribute is attached.
- void buildMutexIDFromExp(Expr *MutexExp, Expr *DeclExp, const NamedDecl *D) {
- CallingContext CallCtx(D);
- // If we are processing a raw attribute expression, with no substitutions.
- if (DeclExp == 0) {
- buildMutexID(MutexExp, 0);
- return;
- }
- // Examine DeclExp to find SelfArg and FunArgs, which are used to substitute
- // for formal parameters when we call buildMutexID later.
- if (MemberExpr *ME = dyn_cast<MemberExpr>(DeclExp)) {
- CallCtx.SelfArg = ME->getBase();
- } else if (CXXMemberCallExpr *CE = dyn_cast<CXXMemberCallExpr>(DeclExp)) {
- CallCtx.SelfArg = CE->getImplicitObjectArgument();
- CallCtx.NumArgs = CE->getNumArgs();
- CallCtx.FunArgs = CE->getArgs();
- } else if (CallExpr *CE = dyn_cast<CallExpr>(DeclExp)) {
- CallCtx.NumArgs = CE->getNumArgs();
- CallCtx.FunArgs = CE->getArgs();
- } else if (CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(DeclExp)) {
- CallCtx.SelfArg = 0; // FIXME -- get the parent from DeclStmt
- CallCtx.NumArgs = CE->getNumArgs();
- CallCtx.FunArgs = CE->getArgs();
- } else if (D && isa<CXXDestructorDecl>(D)) {
- // There's no such thing as a "destructor call" in the AST.
- CallCtx.SelfArg = DeclExp;
- }
- // If the attribute has no arguments, then assume the argument is "this".
- if (MutexExp == 0) {
- buildMutexID(CallCtx.SelfArg, 0);
- return;
- }
- // For most attributes.
- buildMutexID(MutexExp, &CallCtx);
- }
- public:
- explicit MutexID(clang::Decl::EmptyShell e) {
- DeclSeq.clear();
- }
- /// \param MutexExp The original mutex expression within an attribute
- /// \param DeclExp An expression involving the Decl on which the attribute
- /// occurs.
- /// \param D The declaration to which the lock/unlock attribute is attached.
- /// Caller must check isValid() after construction.
- MutexID(Expr* MutexExp, Expr *DeclExp, const NamedDecl* D) {
- buildMutexIDFromExp(MutexExp, DeclExp, D);
- }
- /// Return true if this is a valid decl sequence.
- /// Caller must call this by hand after construction to handle errors.
- bool isValid() const {
- return !DeclSeq.empty();
- }
- /// Issue a warning about an invalid lock expression
- static void warnInvalidLock(ThreadSafetyHandler &Handler, Expr* MutexExp,
- Expr *DeclExp, const NamedDecl* D) {
- SourceLocation Loc;
- if (DeclExp)
- Loc = DeclExp->getExprLoc();
- // FIXME: add a note about the attribute location in MutexExp or D
- if (Loc.isValid())
- Handler.handleInvalidLockExp(Loc);
- }
- bool operator==(const MutexID &other) const {
- return DeclSeq == other.DeclSeq;
- }
- bool operator!=(const MutexID &other) const {
- return !(*this == other);
- }
- // SmallVector overloads Operator< to do lexicographic ordering. Note that
- // we use pointer equality (and <) to compare NamedDecls. This means the order
- // of MutexIDs in a lockset is nondeterministic. In order to output
- // diagnostics in a deterministic ordering, we must order all diagnostics to
- // output by SourceLocation when iterating through this lockset.
- bool operator<(const MutexID &other) const {
- return DeclSeq < other.DeclSeq;
- }
- /// \brief Returns the name of the first Decl in the list for a given MutexID;
- /// e.g. the lock expression foo.bar() has name "bar".
- /// The caret will point unambiguously to the lock expression, so using this
- /// name in diagnostics is a way to get simple, and consistent, mutex names.
- /// We do not want to output the entire expression text for security reasons.
- std::string getName() const {
- assert(isValid());
- if (!DeclSeq.front())
- return "this"; // Use 0 to represent 'this'.
- return DeclSeq.front()->getNameAsString();
- }
- void Profile(llvm::FoldingSetNodeID &ID) const {
- for (SmallVectorImpl<NamedDecl*>::const_iterator I = DeclSeq.begin(),
- E = DeclSeq.end(); I != E; ++I) {
- ID.AddPointer(*I);
- }
- }
- };
- /// \brief This is a helper class that stores info about the most recent
- /// accquire of a Lock.
- ///
- /// The main body of the analysis maps MutexIDs to LockDatas.
- struct LockData {
- SourceLocation AcquireLoc;
- /// \brief LKind stores whether a lock is held shared or exclusively.
- /// Note that this analysis does not currently support either re-entrant
- /// locking or lock "upgrading" and "downgrading" between exclusive and
- /// shared.
- ///
- /// FIXME: add support for re-entrant locking and lock up/downgrading
- LockKind LKind;
- bool Managed; // for ScopedLockable objects
- MutexID UnderlyingMutex; // for ScopedLockable objects
- LockData(SourceLocation AcquireLoc, LockKind LKind, bool M = false)
- : AcquireLoc(AcquireLoc), LKind(LKind), Managed(M),
- UnderlyingMutex(Decl::EmptyShell())
- {}
- LockData(SourceLocation AcquireLoc, LockKind LKind, const MutexID &Mu)
- : AcquireLoc(AcquireLoc), LKind(LKind), Managed(false),
- UnderlyingMutex(Mu)
- {}
- bool operator==(const LockData &other) const {
- return AcquireLoc == other.AcquireLoc && LKind == other.LKind;
- }
- bool operator!=(const LockData &other) const {
- return !(*this == other);
- }
- void Profile(llvm::FoldingSetNodeID &ID) const {
- ID.AddInteger(AcquireLoc.getRawEncoding());
- ID.AddInteger(LKind);
- }
- };
- /// A Lockset maps each MutexID (defined above) to information about how it has
- /// been locked.
- typedef llvm::ImmutableMap<MutexID, LockData> Lockset;
- typedef llvm::ImmutableMap<const NamedDecl*, unsigned> LocalVarContext;
- class LocalVariableMap;
- /// A side (entry or exit) of a CFG node.
- enum CFGBlockSide { CBS_Entry, CBS_Exit };
- /// CFGBlockInfo is a struct which contains all the information that is
- /// maintained for each block in the CFG. See LocalVariableMap for more
- /// information about the contexts.
- struct CFGBlockInfo {
- Lockset EntrySet; // Lockset held at entry to block
- Lockset ExitSet; // Lockset held at exit from block
- LocalVarContext EntryContext; // Context held at entry to block
- LocalVarContext ExitContext; // Context held at exit from block
- SourceLocation EntryLoc; // Location of first statement in block
- SourceLocation ExitLoc; // Location of last statement in block.
- unsigned EntryIndex; // Used to replay contexts later
- const Lockset &getSet(CFGBlockSide Side) const {
- return Side == CBS_Entry ? EntrySet : ExitSet;
- }
- SourceLocation getLocation(CFGBlockSide Side) const {
- return Side == CBS_Entry ? EntryLoc : ExitLoc;
- }
- private:
- CFGBlockInfo(Lockset EmptySet, LocalVarContext EmptyCtx)
- : EntrySet(EmptySet), ExitSet(EmptySet),
- EntryContext(EmptyCtx), ExitContext(EmptyCtx)
- { }
- public:
- static CFGBlockInfo getEmptyBlockInfo(Lockset::Factory &F,
- LocalVariableMap &M);
- };
- // A LocalVariableMap maintains a map from local variables to their currently
- // valid definitions. It provides SSA-like functionality when traversing the
- // CFG. Like SSA, each definition or assignment to a variable is assigned a
- // unique name (an integer), which acts as the SSA name for that definition.
- // The total set of names is shared among all CFG basic blocks.
- // Unlike SSA, we do not rewrite expressions to replace local variables declrefs
- // with their SSA-names. Instead, we compute a Context for each point in the
- // code, which maps local variables to the appropriate SSA-name. This map
- // changes with each assignment.
- //
- // The map is computed in a single pass over the CFG. Subsequent analyses can
- // then query the map to find the appropriate Context for a statement, and use
- // that Context to look up the definitions of variables.
- class LocalVariableMap {
- public:
- typedef LocalVarContext Context;
- /// A VarDefinition consists of an expression, representing the value of the
- /// variable, along with the context in which that expression should be
- /// interpreted. A reference VarDefinition does not itself contain this
- /// information, but instead contains a pointer to a previous VarDefinition.
- struct VarDefinition {
- public:
- friend class LocalVariableMap;
- const NamedDecl *Dec; // The original declaration for this variable.
- const Expr *Exp; // The expression for this variable, OR
- unsigned Ref; // Reference to another VarDefinition
- Context Ctx; // The map with which Exp should be interpreted.
- bool isReference() { return !Exp; }
- private:
- // Create ordinary variable definition
- VarDefinition(const NamedDecl *D, const Expr *E, Context C)
- : Dec(D), Exp(E), Ref(0), Ctx(C)
- { }
- // Create reference to previous definition
- VarDefinition(const NamedDecl *D, unsigned R, Context C)
- : Dec(D), Exp(0), Ref(R), Ctx(C)
- { }
- };
- private:
- Context::Factory ContextFactory;
- std::vector<VarDefinition> VarDefinitions;
- std::vector<unsigned> CtxIndices;
- std::vector<std::pair<Stmt*, Context> > SavedContexts;
- public:
- LocalVariableMap() {
- // index 0 is a placeholder for undefined variables (aka phi-nodes).
- VarDefinitions.push_back(VarDefinition(0, 0u, getEmptyContext()));
- }
- /// Look up a definition, within the given context.
- const VarDefinition* lookup(const NamedDecl *D, Context Ctx) {
- const unsigned *i = Ctx.lookup(D);
- if (!i)
- return 0;
- assert(*i < VarDefinitions.size());
- return &VarDefinitions[*i];
- }
- /// Look up the definition for D within the given context. Returns
- /// NULL if the expression is not statically known. If successful, also
- /// modifies Ctx to hold the context of the return Expr.
- const Expr* lookupExpr(const NamedDecl *D, Context &Ctx) {
- const unsigned *P = Ctx.lookup(D);
- if (!P)
- return 0;
- unsigned i = *P;
- while (i > 0) {
- if (VarDefinitions[i].Exp) {
- Ctx = VarDefinitions[i].Ctx;
- return VarDefinitions[i].Exp;
- }
- i = VarDefinitions[i].Ref;
- }
- return 0;
- }
- Context getEmptyContext() { return ContextFactory.getEmptyMap(); }
- /// Return the next context after processing S. This function is used by
- /// clients of the class to get the appropriate context when traversing the
- /// CFG. It must be called for every assignment or DeclStmt.
- Context getNextContext(unsigned &CtxIndex, Stmt *S, Context C) {
- if (SavedContexts[CtxIndex+1].first == S) {
- CtxIndex++;
- Context Result = SavedContexts[CtxIndex].second;
- return Result;
- }
- return C;
- }
- void dumpVarDefinitionName(unsigned i) {
- if (i == 0) {
- llvm::errs() << "Undefined";
- return;
- }
- const NamedDecl *Dec = VarDefinitions[i].Dec;
- if (!Dec) {
- llvm::errs() << "<<NULL>>";
- return;
- }
- Dec->printName(llvm::errs());
- llvm::errs() << "." << i << " " << ((void*) Dec);
- }
- /// Dumps an ASCII representation of the variable map to llvm::errs()
- void dump() {
- for (unsigned i = 1, e = VarDefinitions.size(); i < e; ++i) {
- const Expr *Exp = VarDefinitions[i].Exp;
- unsigned Ref = VarDefinitions[i].Ref;
- dumpVarDefinitionName(i);
- llvm::errs() << " = ";
- if (Exp) Exp->dump();
- else {
- dumpVarDefinitionName(Ref);
- llvm::errs() << "\n";
- }
- }
- }
- /// Dumps an ASCII representation of a Context to llvm::errs()
- void dumpContext(Context C) {
- for (Context::iterator I = C.begin(), E = C.end(); I != E; ++I) {
- const NamedDecl *D = I.getKey();
- D->printName(llvm::errs());
- const unsigned *i = C.lookup(D);
- llvm::errs() << " -> ";
- dumpVarDefinitionName(*i);
- llvm::errs() << "\n";
- }
- }
- /// Builds the variable map.
- void traverseCFG(CFG *CFGraph, PostOrderCFGView *SortedGraph,
- std::vector<CFGBlockInfo> &BlockInfo);
- protected:
- // Get the current context index
- unsigned getContextIndex() { return SavedContexts.size()-1; }
- // Save the current context for later replay
- void saveContext(Stmt *S, Context C) {
- SavedContexts.push_back(std::make_pair(S,C));
- }
- // Adds a new definition to the given context, and returns a new context.
- // This method should be called when declaring a new variable.
- Context addDefinition(const NamedDecl *D, Expr *Exp, Context Ctx) {
- assert(!Ctx.contains(D));
- unsigned newID = VarDefinitions.size();
- Context NewCtx = ContextFactory.add(Ctx, D, newID);
- VarDefinitions.push_back(VarDefinition(D, Exp, Ctx));
- return NewCtx;
- }
- // Add a new reference to an existing definition.
- Context addReference(const NamedDecl *D, unsigned i, Context Ctx) {
- unsigned newID = VarDefinitions.size();
- Context NewCtx = ContextFactory.add(Ctx, D, newID);
- VarDefinitions.push_back(VarDefinition(D, i, Ctx));
- return NewCtx;
- }
- // Updates a definition only if that definition is already in the map.
- // This method should be called when assigning to an existing variable.
- Context updateDefinition(const NamedDecl *D, Expr *Exp, Context Ctx) {
- if (Ctx.contains(D)) {
- unsigned newID = VarDefinitions.size();
- Context NewCtx = ContextFactory.remove(Ctx, D);
- NewCtx = ContextFactory.add(NewCtx, D, newID);
- VarDefinitions.push_back(VarDefinition(D, Exp, Ctx));
- return NewCtx;
- }
- return Ctx;
- }
- // Removes a definition from the context, but keeps the variable name
- // as a valid variable. The index 0 is a placeholder for cleared definitions.
- Context clearDefinition(const NamedDecl *D, Context Ctx) {
- Context NewCtx = Ctx;
- if (NewCtx.contains(D)) {
- NewCtx = ContextFactory.remove(NewCtx, D);
- NewCtx = ContextFactory.add(NewCtx, D, 0);
- }
- return NewCtx;
- }
- // Remove a definition entirely frmo the context.
- Context removeDefinition(const NamedDecl *D, Context Ctx) {
- Context NewCtx = Ctx;
- if (NewCtx.contains(D)) {
- NewCtx = ContextFactory.remove(NewCtx, D);
- }
- return NewCtx;
- }
- Context intersectContexts(Context C1, Context C2);
- Context createReferenceContext(Context C);
- void intersectBackEdge(Context C1, Context C2);
- friend class VarMapBuilder;
- };
- // This has to be defined after LocalVariableMap.
- CFGBlockInfo CFGBlockInfo::getEmptyBlockInfo(Lockset::Factory &F,
- LocalVariableMap &M) {
- return CFGBlockInfo(F.getEmptyMap(), M.getEmptyContext());
- }
- /// Visitor which builds a LocalVariableMap
- class VarMapBuilder : public StmtVisitor<VarMapBuilder> {
- public:
- LocalVariableMap* VMap;
- LocalVariableMap::Context Ctx;
- VarMapBuilder(LocalVariableMap *VM, LocalVariableMap::Context C)
- : VMap(VM), Ctx(C) {}
- void VisitDeclStmt(DeclStmt *S);
- void VisitBinaryOperator(BinaryOperator *BO);
- };
- // Add new local variables to the variable map
- void VarMapBuilder::VisitDeclStmt(DeclStmt *S) {
- bool modifiedCtx = false;
- DeclGroupRef DGrp = S->getDeclGroup();
- for (DeclGroupRef::iterator I = DGrp.begin(), E = DGrp.end(); I != E; ++I) {
- if (VarDecl *VD = dyn_cast_or_null<VarDecl>(*I)) {
- Expr *E = VD->getInit();
- // Add local variables with trivial type to the variable map
- QualType T = VD->getType();
- if (T.isTrivialType(VD->getASTContext())) {
- Ctx = VMap->addDefinition(VD, E, Ctx);
- modifiedCtx = true;
- }
- }
- }
- if (modifiedCtx)
- VMap->saveContext(S, Ctx);
- }
- // Update local variable definitions in variable map
- void VarMapBuilder::VisitBinaryOperator(BinaryOperator *BO) {
- if (!BO->isAssignmentOp())
- return;
- Expr *LHSExp = BO->getLHS()->IgnoreParenCasts();
- // Update the variable map and current context.
- if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(LHSExp)) {
- ValueDecl *VDec = DRE->getDecl();
- if (Ctx.lookup(VDec)) {
- if (BO->getOpcode() == BO_Assign)
- Ctx = VMap->updateDefinition(VDec, BO->getRHS(), Ctx);
- else
- // FIXME -- handle compound assignment operators
- Ctx = VMap->clearDefinition(VDec, Ctx);
- VMap->saveContext(BO, Ctx);
- }
- }
- }
- // Computes the intersection of two contexts. The intersection is the
- // set of variables which have the same definition in both contexts;
- // variables with different definitions are discarded.
- LocalVariableMap::Context
- LocalVariableMap::intersectContexts(Context C1, Context C2) {
- Context Result = C1;
- for (Context::iterator I = C1.begin(), E = C1.end(); I != E; ++I) {
- const NamedDecl *Dec = I.getKey();
- unsigned i1 = I.getData();
- const unsigned *i2 = C2.lookup(Dec);
- if (!i2) // variable doesn't exist on second path
- Result = removeDefinition(Dec, Result);
- else if (*i2 != i1) // variable exists, but has different definition
- Result = clearDefinition(Dec, Result);
- }
- return Result;
- }
- // For every variable in C, create a new variable that refers to the
- // definition in C. Return a new context that contains these new variables.
- // (We use this for a naive implementation of SSA on loop back-edges.)
- LocalVariableMap::Context LocalVariableMap::createReferenceContext(Context C) {
- Context Result = getEmptyContext();
- for (Context::iterator I = C.begin(), E = C.end(); I != E; ++I) {
- const NamedDecl *Dec = I.getKey();
- unsigned i = I.getData();
- Result = addReference(Dec, i, Result);
- }
- return Result;
- }
- // This routine also takes the intersection of C1 and C2, but it does so by
- // altering the VarDefinitions. C1 must be the result of an earlier call to
- // createReferenceContext.
- void LocalVariableMap::intersectBackEdge(Context C1, Context C2) {
- for (Context::iterator I = C1.begin(), E = C1.end(); I != E; ++I) {
- const NamedDecl *Dec = I.getKey();
- unsigned i1 = I.getData();
- VarDefinition *VDef = &VarDefinitions[i1];
- assert(VDef->isReference());
- const unsigned *i2 = C2.lookup(Dec);
- if (!i2 || (*i2 != i1))
- VDef->Ref = 0; // Mark this variable as undefined
- }
- }
- // Traverse the CFG in topological order, so all predecessors of a block
- // (excluding back-edges) are visited before the block itself. At
- // each point in the code, we calculate a Context, which holds the set of
- // variable definitions which are visible at that point in execution.
- // Visible variables are mapped to their definitions using an array that
- // contains all definitions.
- //
- // At join points in the CFG, the set is computed as the intersection of
- // the incoming sets along each edge, E.g.
- //
- // { Context | VarDefinitions }
- // int x = 0; { x -> x1 | x1 = 0 }
- // int y = 0; { x -> x1, y -> y1 | y1 = 0, x1 = 0 }
- // if (b) x = 1; { x -> x2, y -> y1 | x2 = 1, y1 = 0, ... }
- // else x = 2; { x -> x3, y -> y1 | x3 = 2, x2 = 1, ... }
- // ... { y -> y1 (x is unknown) | x3 = 2, x2 = 1, ... }
- //
- // This is essentially a simpler and more naive version of the standard SSA
- // algorithm. Those definitions that remain in the intersection are from blocks
- // that strictly dominate the current block. We do not bother to insert proper
- // phi nodes, because they are not used in our analysis; instead, wherever
- // a phi node would be required, we simply remove that definition from the
- // context (E.g. x above).
- //
- // The initial traversal does not capture back-edges, so those need to be
- // handled on a separate pass. Whenever the first pass encounters an
- // incoming back edge, it duplicates the context, creating new definitions
- // that refer back to the originals. (These correspond to places where SSA
- // might have to insert a phi node.) On the second pass, these definitions are
- // set to NULL if the the variable has changed on the back-edge (i.e. a phi
- // node was actually required.) E.g.
- //
- // { Context | VarDefinitions }
- // int x = 0, y = 0; { x -> x1, y -> y1 | y1 = 0, x1 = 0 }
- // while (b) { x -> x2, y -> y1 | [1st:] x2=x1; [2nd:] x2=NULL; }
- // x = x+1; { x -> x3, y -> y1 | x3 = x2 + 1, ... }
- // ... { y -> y1 | x3 = 2, x2 = 1, ... }
- //
- void LocalVariableMap::traverseCFG(CFG *CFGraph,
- PostOrderCFGView *SortedGraph,
- std::vector<CFGBlockInfo> &BlockInfo) {
- PostOrderCFGView::CFGBlockSet VisitedBlocks(CFGraph);
- CtxIndices.resize(CFGraph->getNumBlockIDs());
- for (PostOrderCFGView::iterator I = SortedGraph->begin(),
- E = SortedGraph->end(); I!= E; ++I) {
- const CFGBlock *CurrBlock = *I;
- int CurrBlockID = CurrBlock->getBlockID();
- CFGBlockInfo *CurrBlockInfo = &BlockInfo[CurrBlockID];
- VisitedBlocks.insert(CurrBlock);
- // Calculate the entry context for the current block
- bool HasBackEdges = false;
- bool CtxInit = true;
- for (CFGBlock::const_pred_iterator PI = CurrBlock->pred_begin(),
- PE = CurrBlock->pred_end(); PI != PE; ++PI) {
- // if *PI -> CurrBlock is a back edge, so skip it
- if (*PI == 0 || !VisitedBlocks.alreadySet(*PI)) {
- HasBackEdges = true;
- continue;
- }
- int PrevBlockID = (*PI)->getBlockID();
- CFGBlockInfo *PrevBlockInfo = &BlockInfo[PrevBlockID];
- if (CtxInit) {
- CurrBlockInfo->EntryContext = PrevBlockInfo->ExitContext;
- CtxInit = false;
- }
- else {
- CurrBlockInfo->EntryContext =
- intersectContexts(CurrBlockInfo->EntryContext,
- PrevBlockInfo->ExitContext);
- }
- }
- // Duplicate the context if we have back-edges, so we can call
- // intersectBackEdges later.
- if (HasBackEdges)
- CurrBlockInfo->EntryContext =
- createReferenceContext(CurrBlockInfo->EntryContext);
- // Create a starting context index for the current block
- saveContext(0, CurrBlockInfo->EntryContext);
- CurrBlockInfo->EntryIndex = getContextIndex();
- // Visit all the statements in the basic block.
- VarMapBuilder VMapBuilder(this, CurrBlockInfo->EntryContext);
- for (CFGBlock::const_iterator BI = CurrBlock->begin(),
- BE = CurrBlock->end(); BI != BE; ++BI) {
- switch (BI->getKind()) {
- case CFGElement::Statement: {
- const CFGStmt *CS = cast<CFGStmt>(&*BI);
- VMapBuilder.Visit(const_cast<Stmt*>(CS->getStmt()));
- break;
- }
- default:
- break;
- }
- }
- CurrBlockInfo->ExitContext = VMapBuilder.Ctx;
- // Mark variables on back edges as "unknown" if they've been changed.
- for (CFGBlock::const_succ_iterator SI = CurrBlock->succ_begin(),
- SE = CurrBlock->succ_end(); SI != SE; ++SI) {
- // if CurrBlock -> *SI is *not* a back edge
- if (*SI == 0 || !VisitedBlocks.alreadySet(*SI))
- continue;
- CFGBlock *FirstLoopBlock = *SI;
- Context LoopBegin = BlockInfo[FirstLoopBlock->getBlockID()].EntryContext;
- Context LoopEnd = CurrBlockInfo->ExitContext;
- intersectBackEdge(LoopBegin, LoopEnd);
- }
- }
- // Put an extra entry at the end of the indexed context array
- unsigned exitID = CFGraph->getExit().getBlockID();
- saveContext(0, BlockInfo[exitID].ExitContext);
- }
- /// Find the appropriate source locations to use when producing diagnostics for
- /// each block in the CFG.
- static void findBlockLocations(CFG *CFGraph,
- PostOrderCFGView *SortedGraph,
- std::vector<CFGBlockInfo> &BlockInfo) {
- for (PostOrderCFGView::iterator I = SortedGraph->begin(),
- E = SortedGraph->end(); I!= E; ++I) {
- const CFGBlock *CurrBlock = *I;
- CFGBlockInfo *CurrBlockInfo = &BlockInfo[CurrBlock->getBlockID()];
- // Find the source location of the last statement in the block, if the
- // block is not empty.
- if (const Stmt *S = CurrBlock->getTerminator()) {
- CurrBlockInfo->EntryLoc = CurrBlockInfo->ExitLoc = S->getLocStart();
- } else {
- for (CFGBlock::const_reverse_iterator BI = CurrBlock->rbegin(),
- BE = CurrBlock->rend(); BI != BE; ++BI) {
- // FIXME: Handle other CFGElement kinds.
- if (const CFGStmt *CS = dyn_cast<CFGStmt>(&*BI)) {
- CurrBlockInfo->ExitLoc = CS->getStmt()->getLocStart();
- break;
- }
- }
- }
- if (!CurrBlockInfo->ExitLoc.isInvalid()) {
- // This block contains at least one statement. Find the source location
- // of the first statement in the block.
- for (CFGBlock::const_iterator BI = CurrBlock->begin(),
- BE = CurrBlock->end(); BI != BE; ++BI) {
- // FIXME: Handle other CFGElement kinds.
- if (const CFGStmt *CS = dyn_cast<CFGStmt>(&*BI)) {
- CurrBlockInfo->EntryLoc = CS->getStmt()->getLocStart();
- break;
- }
- }
- } else if (CurrBlock->pred_size() == 1 && *CurrBlock->pred_begin() &&
- CurrBlock != &CFGraph->getExit()) {
- // The block is empty, and has a single predecessor. Use its exit
- // location.
- CurrBlockInfo->EntryLoc = CurrBlockInfo->ExitLoc =
- BlockInfo[(*CurrBlock->pred_begin())->getBlockID()].ExitLoc;
- }
- }
- }
- /// \brief Class which implements the core thread safety analysis routines.
- class ThreadSafetyAnalyzer {
- friend class BuildLockset;
- ThreadSafetyHandler &Handler;
- Lockset::Factory LocksetFactory;
- LocalVariableMap LocalVarMap;
- std::vector<CFGBlockInfo> BlockInfo;
- public:
- ThreadSafetyAnalyzer(ThreadSafetyHandler &H) : Handler(H) {}
- Lockset addLock(const Lockset &LSet, const MutexID &Mutex,
- const LockData &LDat, bool Warn=true);
- Lockset addLock(const Lockset &LSet, Expr *MutexExp, const NamedDecl *D,
- const LockData &LDat, bool Warn=true);
- Lockset removeLock(const Lockset &LSet, const MutexID &Mutex,
- SourceLocation UnlockLoc,
- bool Warn=true, bool FullyRemove=false);
- template <class AttrType>
- Lockset addLocksToSet(const Lockset &LSet, LockKind LK, AttrType *Attr,
- Expr *Exp, NamedDecl *D, VarDecl *VD = 0);
- Lockset removeLocksFromSet(const Lockset &LSet,
- UnlockFunctionAttr *Attr,
- Expr *Exp, NamedDecl* FunDecl);
- template <class AttrType>
- Lockset addTrylock(const Lockset &LSet,
- LockKind LK, AttrType *Attr, Expr *Exp, NamedDecl *FunDecl,
- const CFGBlock* PredBlock, const CFGBlock *CurrBlock,
- Expr *BrE, bool Neg);
- const CallExpr* getTrylockCallExpr(const Stmt *Cond, LocalVarContext C,
- bool &Negate);
- Lockset getEdgeLockset(const Lockset &ExitSet,
- const CFGBlock* PredBlock,
- const CFGBlock *CurrBlock);
- Lockset intersectAndWarn(const Lockset &LSet1, const Lockset &LSet2,
- SourceLocation JoinLoc, LockErrorKind LEK);
- void runAnalysis(AnalysisDeclContext &AC);
- };
- /// \brief Add a new lock to the lockset, warning if the lock is already there.
- /// \param Mutex -- the Mutex expression for the lock
- /// \param LDat -- the LockData for the lock
- Lockset ThreadSafetyAnalyzer::addLock(const Lockset &LSet,
- const MutexID &Mutex,
- const LockData &LDat,
- bool Warn) {
- // FIXME: deal with acquired before/after annotations.
- // FIXME: Don't always warn when we have support for reentrant locks.
- if (LSet.lookup(Mutex)) {
- if (Warn)
- Handler.handleDoubleLock(Mutex.getName(), LDat.AcquireLoc);
- return LSet;
- } else {
- return LocksetFactory.add(LSet, Mutex, LDat);
- }
- }
- /// \brief Construct a new mutex and add it to the lockset.
- Lockset ThreadSafetyAnalyzer::addLock(const Lockset &LSet,
- Expr *MutexExp, const NamedDecl *D,
- const LockData &LDat,
- bool Warn) {
- MutexID Mutex(MutexExp, 0, D);
- if (!Mutex.isValid()) {
- MutexID::warnInvalidLock(Handler, MutexExp, 0, D);
- return LSet;
- }
- return addLock(LSet, Mutex, LDat, Warn);
- }
- /// \brief Remove a lock from the lockset, warning if the lock is not there.
- /// \param LockExp The lock expression corresponding to the lock to be removed
- /// \param UnlockLoc The source location of the unlock (only used in error msg)
- Lockset ThreadSafetyAnalyzer::removeLock(const Lockset &LSet,
- const MutexID &Mutex,
- SourceLocation UnlockLoc,
- bool Warn, bool FullyRemove) {
- const LockData *LDat = LSet.lookup(Mutex);
- if (!LDat) {
- if (Warn)
- Handler.handleUnmatchedUnlock(Mutex.getName(), UnlockLoc);
- return LSet;
- }
- else {
- Lockset Result = LSet;
- if (LDat->UnderlyingMutex.isValid()) {
- // For scoped-lockable vars, remove the mutex associated with this var.
- Result = removeLock(Result, LDat->UnderlyingMutex, UnlockLoc,
- false, true);
- // Fully remove the object only when the destructor is called
- if (FullyRemove)
- return LocksetFactory.remove(Result, Mutex);
- else
- return Result;
- }
- return LocksetFactory.remove(Result, Mutex);
- }
- }
- /// \brief This function, parameterized by an attribute type, is used to add a
- /// set of locks specified as attribute arguments to the lockset.
- template <typename AttrType>
- Lockset ThreadSafetyAnalyzer::addLocksToSet(const Lockset &LSet,
- LockKind LK, AttrType *Attr,
- Expr *Exp, NamedDecl* FunDecl,
- VarDecl *VD) {
- typedef typename AttrType::args_iterator iterator_type;
- SourceLocation ExpLocation = Exp->getExprLoc();
- // Figure out if we're calling the constructor of scoped lockable class
- bool isScopedVar = false;
- if (VD) {
- if (CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(FunDecl)) {
- CXXRecordDecl* PD = CD->getParent();
- if (PD && PD->getAttr<ScopedLockableAttr>())
- isScopedVar = true;
- }
- }
- if (Attr->args_size() == 0) {
- // The mutex held is the "this" object.
- MutexID Mutex(0, Exp, FunDecl);
- if (!Mutex.isValid()) {
- MutexID::warnInvalidLock(Handler, 0, Exp, FunDecl);
- return LSet;
- }
- else {
- return addLock(LSet, Mutex, LockData(ExpLocation, LK));
- }
- }
- Lockset Result = LSet;
- for (iterator_type I=Attr->args_begin(), E=Attr->args_end(); I != E; ++I) {
- MutexID Mutex(*I, Exp, FunDecl);
- if (!Mutex.isValid())
- MutexID::warnInvalidLock(Handler, *I, Exp, FunDecl);
- else {
- if (isScopedVar) {
- // Mutex is managed by scoped var -- suppress certain warnings.
- Result = addLock(Result, Mutex, LockData(ExpLocation, LK, true));
- // For scoped lockable vars, map this var to its underlying mutex.
- DeclRefExpr DRE(VD, false, VD->getType(), VK_LValue, VD->getLocation());
- MutexID SMutex(&DRE, 0, 0);
- Result = addLock(Result, SMutex,
- LockData(VD->getLocation(), LK, Mutex));
- }
- else {
- Result = addLock(Result, Mutex, LockData(ExpLocation, LK));
- }
- }
- }
- return Result;
- }
- /// \brief This function removes a set of locks specified as attribute
- /// arguments from the lockset.
- Lockset ThreadSafetyAnalyzer::removeLocksFromSet(const Lockset &LSet,
- UnlockFunctionAttr *Attr,
- Expr *Exp,
- NamedDecl* FunDecl) {
- SourceLocation ExpLocation;
- if (Exp) ExpLocation = Exp->getExprLoc();
- bool Dtor = isa<CXXDestructorDecl>(FunDecl);
- if (Attr->args_size() == 0) {
- // The mutex held is the "this" object.
- MutexID Mu(0, Exp, FunDecl);
- if (!Mu.isValid()) {
- MutexID::warnInvalidLock(Handler, 0, Exp, FunDecl);
- return LSet;
- } else {
- return removeLock(LSet, Mu, ExpLocation, true, Dtor);
- }
- }
- Lockset Result = LSet;
- for (UnlockFunctionAttr::args_iterator I = Attr->args_begin(),
- E = Attr->args_end(); I != E; ++I) {
- MutexID Mutex(*I, Exp, FunDecl);
- if (!Mutex.isValid())
- MutexID::warnInvalidLock(Handler, *I, Exp, FunDecl);
- else
- Result = removeLock(Result, Mutex, ExpLocation, true, Dtor);
- }
- return Result;
- }
- /// \brief Add lock to set, if the current block is in the taken branch of a
- /// trylock.
- template <class AttrType>
- Lockset ThreadSafetyAnalyzer::addTrylock(const Lockset &LSet,
- LockKind LK, AttrType *Attr,
- Expr *Exp, NamedDecl *FunDecl,
- const CFGBlock *PredBlock,
- const CFGBlock *CurrBlock,
- Expr *BrE, bool Neg) {
- // Find out which branch has the lock
- bool branch = 0;
- if (CXXBoolLiteralExpr *BLE = dyn_cast_or_null<CXXBoolLiteralExpr>(BrE)) {
- branch = BLE->getValue();
- }
- else if (IntegerLiteral *ILE = dyn_cast_or_null<IntegerLiteral>(BrE)) {
- branch = ILE->getValue().getBoolValue();
- }
- int branchnum = branch ? 0 : 1;
- if (Neg) branchnum = !branchnum;
- Lockset Result = LSet;
- // If we've taken the trylock branch, then add the lock
- int i = 0;
- for (CFGBlock::const_succ_iterator SI = PredBlock->succ_begin(),
- SE = PredBlock->succ_end(); SI != SE && i < 2; ++SI, ++i) {
- if (*SI == CurrBlock && i == branchnum) {
- Result = addLocksToSet(Result, LK, Attr, Exp, FunDecl, 0);
- }
- }
- return Result;
- }
- // If Cond can be traced back to a function call, return the call expression.
- // The negate variable should be called with false, and will be set to true
- // if the function call is negated, e.g. if (!mu.tryLock(...))
- const CallExpr* ThreadSafetyAnalyzer::getTrylockCallExpr(const Stmt *Cond,
- LocalVarContext C,
- bool &Negate) {
- if (!Cond)
- return 0;
- if (const CallExpr *CallExp = dyn_cast<CallExpr>(Cond)) {
- return CallExp;
- }
- else if (const ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(Cond)) {
- return getTrylockCallExpr(CE->getSubExpr(), C, Negate);
- }
- else if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Cond)) {
- const Expr *E = LocalVarMap.lookupExpr(DRE->getDecl(), C);
- return getTrylockCallExpr(E, C, Negate);
- }
- else if (const UnaryOperator *UOP = dyn_cast<UnaryOperator>(Cond)) {
- if (UOP->getOpcode() == UO_LNot) {
- Negate = !Negate;
- return getTrylockCallExpr(UOP->getSubExpr(), C, Negate);
- }
- }
- // FIXME -- handle && and || as well.
- return NULL;
- }
- /// \brief Find the lockset that holds on the edge between PredBlock
- /// and CurrBlock. The edge set is the exit set of PredBlock (passed
- /// as the ExitSet parameter) plus any trylocks, which are conditionally held.
- Lockset ThreadSafetyAnalyzer::getEdgeLockset(const Lockset &ExitSet,
- const CFGBlock *PredBlock,
- const CFGBlock *CurrBlock) {
- if (!PredBlock->getTerminatorCondition())
- return ExitSet;
- bool Negate = false;
- const Stmt *Cond = PredBlock->getTerminatorCondition();
- const CFGBlockInfo *PredBlockInfo = &BlockInfo[PredBlock->getBlockID()];
- const LocalVarContext &LVarCtx = PredBlockInfo->ExitContext;
- CallExpr *Exp = const_cast<CallExpr*>(
- getTrylockCallExpr(Cond, LVarCtx, Negate));
- if (!Exp)
- return ExitSet;
- NamedDecl *FunDecl = dyn_cast_or_null<NamedDecl>(Exp->getCalleeDecl());
- if(!FunDecl || !FunDecl->hasAttrs())
- return ExitSet;
- Lockset Result = ExitSet;
- // If the condition is a call to a Trylock function, then grab the attributes
- AttrVec &ArgAttrs = FunDecl->getAttrs();
- for (unsigned i = 0; i < ArgAttrs.size(); ++i) {
- Attr *Attr = ArgAttrs[i];
- switch (Attr->getKind()) {
- case attr::ExclusiveTrylockFunction: {
- ExclusiveTrylockFunctionAttr *A =
- cast<ExclusiveTrylockFunctionAttr>(Attr);
- Result = addTrylock(Result, LK_Exclusive, A, Exp, FunDecl,
- PredBlock, CurrBlock,
- A->getSuccessValue(), Negate);
- break;
- }
- case attr::SharedTrylockFunction: {
- SharedTrylockFunctionAttr *A =
- cast<SharedTrylockFunctionAttr>(Attr);
- Result = addTrylock(Result, LK_Shared, A, Exp, FunDecl,
- PredBlock, CurrBlock,
- A->getSuccessValue(), Negate);
- break;
- }
- default:
- break;
- }
- }
- return Result;
- }
- /// \brief We use this class to visit different types of expressions in
- /// CFGBlocks, and build up the lockset.
- /// An expression may cause us to add or remove locks from the lockset, or else
- /// output error messages related to missing locks.
- /// FIXME: In future, we may be able to not inherit from a visitor.
- class BuildLockset : public StmtVisitor<BuildLockset> {
- friend class ThreadSafetyAnalyzer;
- ThreadSafetyAnalyzer *Analyzer;
- Lockset LSet;
- LocalVariableMap::Context LVarCtx;
- unsigned CtxIndex;
- // Helper functions
- const ValueDecl *getValueDecl(Expr *Exp);
- void warnIfMutexNotHeld(const NamedDecl *D, Expr *Exp, AccessKind AK,
- Expr *MutexExp, ProtectedOperationKind POK);
- void checkAccess(Expr *Exp, AccessKind AK);
- void checkDereference(Expr *Exp, AccessKind AK);
- void handleCall(Expr *Exp, NamedDecl *D, VarDecl *VD = 0);
- /// \brief Returns true if the lockset contains a lock, regardless of whether
- /// the lock is held exclusively or shared.
- bool locksetContains(const MutexID &Lock) const {
- return LSet.lookup(Lock);
- }
- /// \brief Returns true if the lockset contains a lock with the passed in
- /// locktype.
- bool locksetContains(const MutexID &Lock, LockKind KindRequested) const {
- const LockData *LockHeld = LSet.lookup(Lock);
- return (LockHeld && KindRequested == LockHeld->LKind);
- }
- /// \brief Returns true if the lockset contains a lock with at least the
- /// passed in locktype. So for example, if we pass in LK_Shared, this function
- /// returns true if the lock is held LK_Shared or LK_Exclusive. If we pass in
- /// LK_Exclusive, this function returns true if the lock is held LK_Exclusive.
- bool locksetContainsAtLeast(const MutexID &Lock,
- LockKind KindRequested) const {
- switch (KindRequested) {
- case LK_Shared:
- return locksetContains(Lock);
- case LK_Exclusive:
- return locksetContains(Lock, KindRequested);
- }
- llvm_unreachable("Unknown LockKind");
- }
- public:
- BuildLockset(ThreadSafetyAnalyzer *Anlzr, CFGBlockInfo &Info)
- : StmtVisitor<BuildLockset>(),
- Analyzer(Anlzr),
- LSet(Info.EntrySet),
- LVarCtx(Info.EntryContext),
- CtxIndex(Info.EntryIndex)
- {}
- void VisitUnaryOperator(UnaryOperator *UO);
- void VisitBinaryOperator(BinaryOperator *BO);
- void VisitCastExpr(CastExpr *CE);
- void VisitCallExpr(CallExpr *Exp);
- void VisitCXXConstructExpr(CXXConstructExpr *Exp);
- void VisitDeclStmt(DeclStmt *S);
- };
- /// \brief Gets the value decl pointer from DeclRefExprs or MemberExprs
- const ValueDecl *BuildLockset::getValueDecl(Expr *Exp) {
- if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Exp))
- return DR->getDecl();
- if (const MemberExpr *ME = dyn_cast<MemberExpr>(Exp))
- return ME->getMemberDecl();
- return 0;
- }
- /// \brief Warn if the LSet does not contain a lock sufficient to protect access
- /// of at least the passed in AccessKind.
- void BuildLockset::warnIfMutexNotHeld(const NamedDecl *D, Expr *Exp,
- AccessKind AK, Expr *MutexExp,
- ProtectedOperationKind POK) {
- LockKind LK = getLockKindFromAccessKind(AK);
- MutexID Mutex(MutexExp, Exp, D);
- if (!Mutex.isValid())
- MutexID::warnInvalidLock(Analyzer->Handler, MutexExp, Exp, D);
- else if (!locksetContainsAtLeast(Mutex, LK))
- Analyzer->Handler.handleMutexNotHeld(D, POK, Mutex.getName(), LK,
- Exp->getExprLoc());
- }
- /// \brief This method identifies variable dereferences and checks pt_guarded_by
- /// and pt_guarded_var annotations. Note that we only check these annotations
- /// at the time a pointer is dereferenced.
- /// FIXME: We need to check for other types of pointer dereferences
- /// (e.g. [], ->) and deal with them here.
- /// \param Exp An expression that has been read or written.
- void BuildLockset::checkDereference(Expr *Exp, AccessKind AK) {
- UnaryOperator *UO = dyn_cast<UnaryOperator>(Exp);
- if (!UO || UO->getOpcode() != clang::UO_Deref)
- return;
- Exp = UO->getSubExpr()->IgnoreParenCasts();
- const ValueDecl *D = getValueDecl(Exp);
- if(!D || !D->hasAttrs())
- return;
- if (D->getAttr<PtGuardedVarAttr>() && LSet.isEmpty())
- Analyzer->Handler.handleNoMutexHeld(D, POK_VarDereference, AK,
- Exp->getExprLoc());
- const AttrVec &ArgAttrs = D->getAttrs();
- for(unsigned i = 0, Size = ArgAttrs.size(); i < Size; ++i)
- if (PtGuardedByAttr *PGBAttr = dyn_cast<PtGuardedByAttr>(ArgAttrs[i]))
- warnIfMutexNotHeld(D, Exp, AK, PGBAttr->getArg(), POK_VarDereference);
- }
- /// \brief Checks guarded_by and guarded_var attributes.
- /// Whenever we identify an access (read or write) of a DeclRefExpr or
- /// MemberExpr, we need to check whether there are any guarded_by or
- /// guarded_var attributes, and make sure we hold the appropriate mutexes.
- void BuildLockset::checkAccess(Expr *Exp, AccessKind AK) {
- const ValueDecl *D = getValueDecl(Exp);
- if(!D || !D->hasAttrs())
- return;
- if (D->getAttr<GuardedVarAttr>() && LSet.isEmpty())
- Analyzer->Handler.handleNoMutexHeld(D, POK_VarAccess, AK,
- Exp->getExprLoc());
- const AttrVec &ArgAttrs = D->getAttrs();
- for(unsigned i = 0, Size = ArgAttrs.size(); i < Size; ++i)
- if (GuardedByAttr *GBAttr = dyn_cast<GuardedByAttr>(ArgAttrs[i]))
- warnIfMutexNotHeld(D, Exp, AK, GBAttr->getArg(), POK_VarAccess);
- }
- /// \brief Process a function call, method call, constructor call,
- /// or destructor call. This involves looking at the attributes on the
- /// corresponding function/method/constructor/destructor, issuing warnings,
- /// and updating the locksets accordingly.
- ///
- /// FIXME: For classes annotated with one of the guarded annotations, we need
- /// to treat const method calls as reads and non-const method calls as writes,
- /// and check that the appropriate locks are held. Non-const method calls with
- /// the same signature as const method calls can be also treated as reads.
- ///
- /// FIXME: We need to also visit CallExprs to catch/check global functions.
- ///
- /// FIXME: Do not flag an error for member variables accessed in constructors/
- /// destructors
- void BuildLockset::handleCall(Expr *Exp, NamedDecl *D, VarDecl *VD) {
- AttrVec &ArgAttrs = D->getAttrs();
- for(unsigned i = 0; i < ArgAttrs.size(); ++i) {
- Attr *Attr = ArgAttrs[i];
- switch (Attr->getKind()) {
- // When we encounter an exclusive lock function, we need to add the lock
- // to our lockset with kind exclusive.
- case attr::ExclusiveLockFunction: {
- ExclusiveLockFunctionAttr *A = cast<ExclusiveLockFunctionAttr>(Attr);
- LSet = Analyzer->addLocksToSet(LSet, LK_Exclusive, A, Exp, D, VD);
- break;
- }
- // When we encounter a shared lock function, we need to add the lock
- // to our lockset with kind shared.
- case attr::SharedLockFunction: {
- SharedLockFunctionAttr *A = cast<SharedLockFunctionAttr>(Attr);
- LSet = Analyzer->addLocksToSet(LSet, LK_Shared, A, Exp, D, VD);
- break;
- }
- // When we encounter an unlock function, we need to remove unlocked
- // mutexes from the lockset, and flag a warning if they are not there.
- case attr::UnlockFunction: {
- UnlockFunctionAttr *UFAttr = cast<UnlockFunctionAttr>(Attr);
- LSet = Analyzer->removeLocksFromSet(LSet, UFAttr, Exp, D);
- break;
- }
- case attr::ExclusiveLocksRequired: {
- ExclusiveLocksRequiredAttr *ELRAttr =
- cast<ExclusiveLocksRequiredAttr>(Attr);
- for (ExclusiveLocksRequiredAttr::args_iterator
- I = ELRAttr->args_begin(), E = ELRAttr->args_end(); I != E; ++I)
- warnIfMutexNotHeld(D, Exp, AK_Written, *I, POK_FunctionCall);
- break;
- }
- case attr::SharedLocksRequired: {
- SharedLocksRequiredAttr *SLRAttr = cast<SharedLocksRequiredAttr>(Attr);
- for (SharedLocksRequiredAttr::args_iterator I = SLRAttr->args_begin(),
- E = SLRAttr->args_end(); I != E; ++I)
- warnIfMutexNotHeld(D, Exp, AK_Read, *I, POK_FunctionCall);
- break;
- }
- case attr::LocksExcluded: {
- LocksExcludedAttr *LEAttr = cast<LocksExcludedAttr>(Attr);
- for (LocksExcludedAttr::args_iterator I = LEAttr->args_begin(),
- E = LEAttr->args_end(); I != E; ++I) {
- MutexID Mutex(*I, Exp, D);
- if (!Mutex.isValid())
- MutexID::warnInvalidLock(Analyzer->Handler, *I, Exp, D);
- else if (locksetContains(Mutex))
- Analyzer->Handler.handleFunExcludesLock(D->getName(),
- Mutex.getName(),
- Exp->getExprLoc());
- }
- break;
- }
- // Ignore other (non thread-safety) attributes
- default:
- break;
- }
- }
- }
- /// \brief For unary operations which read and write a variable, we need to
- /// check whether we hold any required mutexes. Reads are checked in
- /// VisitCastExpr.
- void BuildLockset::VisitUnaryOperator(UnaryOperator *UO) {
- switch (UO->getOpcode()) {
- case clang::UO_PostDec:
- case clang::UO_PostInc:
- case clang::UO_PreDec:
- case clang::UO_PreInc: {
- Expr *SubExp = UO->getSubExpr()->IgnoreParenCasts();
- checkAccess(SubExp, AK_Written);
- checkDereference(SubExp, AK_Written);
- break;
- }
- default:
- break;
- }
- }
- /// For binary operations which assign to a variable (writes), we need to check
- /// whether we hold any required mutexes.
- /// FIXME: Deal with non-primitive types.
- void BuildLockset::VisitBinaryOperator(BinaryOperator *BO) {
- if (!BO->isAssignmentOp())
- return;
- // adjust the context
- LVarCtx = Analyzer->LocalVarMap.getNextContext(CtxIndex, BO, LVarCtx);
- Expr *LHSExp = BO->getLHS()->IgnoreParenCasts();
- checkAccess(LHSExp, AK_Written);
- checkDereference(LHSExp, AK_Written);
- }
- /// Whenever we do an LValue to Rvalue cast, we are reading a variable and
- /// need to ensure we hold any required mutexes.
- /// FIXME: Deal with non-primitive types.
- void BuildLockset::VisitCastExpr(CastExpr *CE) {
- if (CE->getCastKind() != CK_LValueToRValue)
- return;
- Expr *SubExp = CE->getSubExpr()->IgnoreParenCasts();
- checkAccess(SubExp, AK_Read);
- checkDereference(SubExp, AK_Read);
- }
- void BuildLockset::VisitCallExpr(CallExpr *Exp) {
- NamedDecl *D = dyn_cast_or_null<NamedDecl>(Exp->getCalleeDecl());
- if(!D || !D->hasAttrs())
- return;
- handleCall(Exp, D);
- }
- void BuildLockset::VisitCXXConstructExpr(CXXConstructExpr *Exp) {
- // FIXME -- only handles constructors in DeclStmt below.
- }
- void BuildLockset::VisitDeclStmt(DeclStmt *S) {
- // adjust the context
- LVarCtx = Analyzer->LocalVarMap.getNextContext(CtxIndex, S, LVarCtx);
- DeclGroupRef DGrp = S->getDeclGroup();
- for (DeclGroupRef::iterator I = DGrp.begin(), E = DGrp.end(); I != E; ++I) {
- Decl *D = *I;
- if (VarDecl *VD = dyn_cast_or_null<VarDecl>(D)) {
- Expr *E = VD->getInit();
- if (CXXConstructExpr *CE = dyn_cast_or_null<CXXConstructExpr>(E)) {
- NamedDecl *CtorD = dyn_cast_or_null<NamedDecl>(CE->getConstructor());
- if (!CtorD || !CtorD->hasAttrs())
- return;
- handleCall(CE, CtorD, VD);
- }
- }
- }
- }
- /// \brief Compute the intersection of two locksets and issue warnings for any
- /// locks in the symmetric difference.
- ///
- /// This function is used at a merge point in the CFG when comparing the lockset
- /// of each branch being merged. For example, given the following sequence:
- /// A; if () then B; else C; D; we need to check that the lockset after B and C
- /// are the same. In the event of a difference, we use the intersection of these
- /// two locksets at the start of D.
- ///
- /// \param LSet1 The first lockset.
- /// \param LSet2 The second lockset.
- /// \param JoinLoc The location of the join point for error reporting
- /// \param LEK The error message to report.
- Lockset ThreadSafetyAnalyzer::intersectAndWarn(const Lockset &LSet1,
- const Lockset &LSet2,
- SourceLocation JoinLoc,
- LockErrorKind LEK) {
- Lockset Intersection = LSet1;
- for (Lockset::iterator I = LSet2.begin(), E = LSet2.end(); I != E; ++I) {
- const MutexID &LSet2Mutex = I.getKey();
- const LockData &LSet2LockData = I.getData();
- if (const LockData *LD = LSet1.lookup(LSet2Mutex)) {
- if (LD->LKind != LSet2LockData.LKind) {
- Handler.handleExclusiveAndShared(LSet2Mutex.getName(),
- LSet2LockData.AcquireLoc,
- LD->AcquireLoc);
- if (LD->LKind != LK_Exclusive)
- Intersection = LocksetFactory.add(Intersection, LSet2Mutex,
- LSet2LockData);
- }
- } else {
- if (!LSet2LockData.Managed)
- Handler.handleMutexHeldEndOfScope(LSet2Mutex.getName(),
- LSet2LockData.AcquireLoc,
- JoinLoc, LEK);
- }
- }
- for (Lockset::iterator I = LSet1.begin(), E = LSet1.end(); I != E; ++I) {
- if (!LSet2.contains(I.getKey())) {
- const MutexID &Mutex = I.getKey();
- const LockData &MissingLock = I.getData();
- if (!MissingLock.Managed)
- Handler.handleMutexHeldEndOfScope(Mutex.getName(),
- MissingLock.AcquireLoc,
- JoinLoc, LEK);
- Intersection = LocksetFactory.remove(Intersection, Mutex);
- }
- }
- return Intersection;
- }
- /// \brief Check a function's CFG for thread-safety violations.
- ///
- /// We traverse the blocks in the CFG, compute the set of mutexes that are held
- /// at the end of each block, and issue warnings for thread safety violations.
- /// Each block in the CFG is traversed exactly once.
- void ThreadSafetyAnalyzer::runAnalysis(AnalysisDeclContext &AC) {
- CFG *CFGraph = AC.getCFG();
- if (!CFGraph) return;
- const NamedDecl *D = dyn_cast_or_null<NamedDecl>(AC.getDecl());
- // AC.dumpCFG(true);
- if (!D)
- return; // Ignore anonymous functions for now.
- if (D->getAttr<NoThreadSafetyAnalysisAttr>())
- return;
- // FIXME: Do something a bit more intelligent inside constructor and
- // destructor code. Constructors and destructors must assume unique access
- // to 'this', so checks on member variable access is disabled, but we should
- // still enable checks on other objects.
- if (isa<CXXConstructorDecl>(D))
- return; // Don't check inside constructors.
- if (isa<CXXDestructorDecl>(D))
- return; // Don't check inside destructors.
- BlockInfo.resize(CFGraph->getNumBlockIDs(),
- CFGBlockInfo::getEmptyBlockInfo(LocksetFactory, LocalVarMap));
- // We need to explore the CFG via a "topological" ordering.
- // That way, we will be guaranteed to have information about required
- // predecessor locksets when exploring a new block.
- PostOrderCFGView *SortedGraph = AC.getAnalysis<PostOrderCFGView>();
- PostOrderCFGView::CFGBlockSet VisitedBlocks(CFGraph);
- // Compute SSA names for local variables
- LocalVarMap.traverseCFG(CFGraph, SortedGraph, BlockInfo);
- // Fill in source locations for all CFGBlocks.
- findBlockLocations(CFGraph, SortedGraph, BlockInfo);
- // Add locks from exclusive_locks_required and shared_locks_required
- // to initial lockset. Also turn off checking for lock and unlock functions.
- // FIXME: is there a more intelligent way to check lock/unlock functions?
- if (!SortedGraph->empty() && D->hasAttrs()) {
- const CFGBlock *FirstBlock = *SortedGraph->begin();
- Lockset &InitialLockset = BlockInfo[FirstBlock->getBlockID()].EntrySet;
- const AttrVec &ArgAttrs = D->getAttrs();
- for (unsigned i = 0; i < ArgAttrs.size(); ++i) {
- Attr *Attr = ArgAttrs[i];
- SourceLocation AttrLoc = Attr->getLocation();
- if (SharedLocksRequiredAttr *SLRAttr
- = dyn_cast<SharedLocksRequiredAttr>(Attr)) {
- for (SharedLocksRequiredAttr::args_iterator
- SLRIter = SLRAttr->args_begin(),
- SLREnd = SLRAttr->args_end(); SLRIter != SLREnd; ++SLRIter)
- InitialLockset = addLock(InitialLockset, *SLRIter, D,
- LockData(AttrLoc, LK_Shared), false);
- } else if (ExclusiveLocksRequiredAttr *ELRAttr
- = dyn_cast<ExclusiveLocksRequiredAttr>(Attr)) {
- for (ExclusiveLocksRequiredAttr::args_iterator
- ELRIter = ELRAttr->args_begin(),
- ELREnd = ELRAttr->args_end(); ELRIter != ELREnd; ++ELRIter)
- InitialLockset = addLock(InitialLockset, *ELRIter, D,
- LockData(AttrLoc, LK_Exclusive), false);
- } else if (isa<UnlockFunctionAttr>(Attr)) {
- // Don't try to check unlock functions for now
- return;
- } else if (isa<ExclusiveLockFunctionAttr>(Attr)) {
- // Don't try to check lock functions for now
- return;
- } else if (isa<SharedLockFunctionAttr>(Attr)) {
- // Don't try to check lock functions for now
- return;
- } else if (isa<ExclusiveTrylockFunctionAttr>(Attr)) {
- // Don't try to check trylock functions for now
- return;
- } else if (isa<SharedTrylockFunctionAttr>(Attr)) {
- // Don't try to check trylock functions for now
- return;
- }
- }
- }
- for (PostOrderCFGView::iterator I = SortedGraph->begin(),
- E = SortedGraph->end(); I!= E; ++I) {
- const CFGBlock *CurrBlock = *I;
- int CurrBlockID = CurrBlock->getBlockID();
- CFGBlockInfo *CurrBlockInfo = &BlockInfo[CurrBlockID];
- // Use the default initial lockset in case there are no predecessors.
- VisitedBlocks.insert(CurrBlock);
- // Iterate through the predecessor blocks and warn if the lockset for all
- // predecessors is not the same. We take the entry lockset of the current
- // block to be the intersection of all previous locksets.
- // FIXME: By keeping the intersection, we may output more errors in future
- // for a lock which is not in the intersection, but was in the union. We
- // may want to also keep the union in future. As an example, let's say
- // the intersection contains Mutex L, and the union contains L and M.
- // Later we unlock M. At this point, we would output an error because we
- // never locked M; although the real error is probably that we forgot to
- // lock M on all code paths. Conversely, let's say that later we lock M.
- // In this case, we should compare against the intersection instead of the
- // union because the real error is probably that we forgot to unlock M on
- // all code paths.
- bool LocksetInitialized = false;
- llvm::SmallVector<CFGBlock*, 8> SpecialBlocks;
- for (CFGBlock::const_pred_iterator PI = CurrBlock->pred_begin(),
- PE = CurrBlock->pred_end(); PI != PE; ++PI) {
- // if *PI -> CurrBlock is a back edge
- if (*PI == 0 || !VisitedBlocks.alreadySet(*PI))
- continue;
- // Ignore edges from blocks that can't return.
- if ((*PI)->hasNoReturnElement())
- continue;
- // If the previous block ended in a 'continue' or 'break' statement, then
- // a difference in locksets is probably due to a bug in that block, rather
- // than in some other predecessor. In that case, keep the other
- // predecessor's lockset.
- if (const Stmt *Terminator = (*PI)->getTerminator()) {
- if (isa<ContinueStmt>(Terminator) || isa<BreakStmt>(Terminator)) {
- SpecialBlocks.push_back(*PI);
- continue;
- }
- }
- int PrevBlockID = (*PI)->getBlockID();
- CFGBlockInfo *PrevBlockInfo = &BlockInfo[PrevBlockID];
- Lockset PrevLockset =
- getEdgeLockset(PrevBlockInfo->ExitSet, *PI, CurrBlock);
- if (!LocksetInitialized) {
- CurrBlockInfo->EntrySet = PrevLockset;
- LocksetInitialized = true;
- } else {
- CurrBlockInfo->EntrySet =
- intersectAndWarn(CurrBlockInfo->EntrySet, PrevLockset,
- CurrBlockInfo->EntryLoc,
- LEK_LockedSomePredecessors);
- }
- }
- // Process continue and break blocks. Assume that the lockset for the
- // resulting block is unaffected by any discrepancies in them.
- for (unsigned SpecialI = 0, SpecialN = SpecialBlocks.size();
- SpecialI < SpecialN; ++SpecialI) {
- CFGBlock *PrevBlock = SpecialBlocks[SpecialI];
- int PrevBlockID = PrevBlock->getBlockID();
- CFGBlockInfo *PrevBlockInfo = &BlockInfo[PrevBlockID];
- if (!LocksetInitialized) {
- CurrBlockInfo->EntrySet = PrevBlockInfo->ExitSet;
- LocksetInitialized = true;
- } else {
- // Determine whether this edge is a loop terminator for diagnostic
- // purposes. FIXME: A 'break' statement might be a loop terminator, but
- // it might also be part of a switch. Also, a subsequent destructor
- // might add to the lockset, in which case the real issue might be a
- // double lock on the other path.
- const Stmt *Terminator = PrevBlock->getTerminator();
- bool IsLoop = Terminator && isa<ContinueStmt>(Terminator);
- Lockset PrevLockset =
- getEdgeLockset(PrevBlockInfo->ExitSet, PrevBlock, CurrBlock);
- // Do not update EntrySet.
- intersectAndWarn(CurrBlockInfo->EntrySet, PrevLockset,
- PrevBlockInfo->ExitLoc,
- IsLoop ? LEK_LockedSomeLoopIterations
- : LEK_LockedSomePredecessors);
- }
- }
- BuildLockset LocksetBuilder(this, *CurrBlockInfo);
- // Visit all the statements in the basic block.
- for (CFGBlock::const_iterator BI = CurrBlock->begin(),
- BE = CurrBlock->end(); BI != BE; ++BI) {
- switch (BI->getKind()) {
- case CFGElement::Statement: {
- const CFGStmt *CS = cast<CFGStmt>(&*BI);
- LocksetBuilder.Visit(const_cast<Stmt*>(CS->getStmt()));
- break;
- }
- // Ignore BaseDtor, MemberDtor, and TemporaryDtor for now.
- case CFGElement::AutomaticObjectDtor: {
- const CFGAutomaticObjDtor *AD = cast<CFGAutomaticObjDtor>(&*BI);
- CXXDestructorDecl *DD = const_cast<CXXDestructorDecl*>(
- AD->getDestructorDecl(AC.getASTContext()));
- if (!DD->hasAttrs())
- break;
- // Create a dummy expression,
- VarDecl *VD = const_cast<VarDecl*>(AD->getVarDecl());
- DeclRefExpr DRE(VD, false, VD->getType(), VK_LValue,
- AD->getTriggerStmt()->getLocEnd());
- LocksetBuilder.handleCall(&DRE, DD);
- break;
- }
- default:
- break;
- }
- }
- CurrBlockInfo->ExitSet = LocksetBuilder.LSet;
- // For every back edge from CurrBlock (the end of the loop) to another block
- // (FirstLoopBlock) we need to check that the Lockset of Block is equal to
- // the one held at the beginning of FirstLoopBlock. We can look up the
- // Lockset held at the beginning of FirstLoopBlock in the EntryLockSets map.
- for (CFGBlock::const_succ_iterator SI = CurrBlock->succ_begin(),
- SE = CurrBlock->succ_end(); SI != SE; ++SI) {
- // if CurrBlock -> *SI is *not* a back edge
- if (*SI == 0 || !VisitedBlocks.alreadySet(*SI))
- continue;
- CFGBlock *FirstLoopBlock = *SI;
- CFGBlockInfo *PreLoop = &BlockInfo[FirstLoopBlock->getBlockID()];
- CFGBlockInfo *LoopEnd = &BlockInfo[CurrBlockID];
- intersectAndWarn(LoopEnd->ExitSet, PreLoop->EntrySet,
- PreLoop->EntryLoc,
- LEK_LockedSomeLoopIterations);
- }
- }
- CFGBlockInfo *Initial = &BlockInfo[CFGraph->getEntry().getBlockID()];
- CFGBlockInfo *Final = &BlockInfo[CFGraph->getExit().getBlockID()];
- // FIXME: Should we call this function for all blocks which exit the function?
- intersectAndWarn(Initial->EntrySet, Final->ExitSet,
- Final->ExitLoc,
- LEK_LockedAtEndOfFunction);
- }
- } // end anonymous namespace
- namespace clang {
- namespace thread_safety {
- /// \brief Check a function's CFG for thread-safety violations.
- ///
- /// We traverse the blocks in the CFG, compute the set of mutexes that are held
- /// at the end of each block, and issue warnings for thread safety violations.
- /// Each block in the CFG is traversed exactly once.
- void runThreadSafetyAnalysis(AnalysisDeclContext &AC,
- ThreadSafetyHandler &Handler) {
- ThreadSafetyAnalyzer Analyzer(Handler);
- Analyzer.runAnalysis(AC);
- }
- /// \brief Helper function that returns a LockKind required for the given level
- /// of access.
- LockKind getLockKindFromAccessKind(AccessKind AK) {
- switch (AK) {
- case AK_Read :
- return LK_Shared;
- case AK_Written :
- return LK_Exclusive;
- }
- llvm_unreachable("Unknown AccessKind");
- }
- }} // end namespace clang::thread_safety
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