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authorDimitry Andric <dim@FreeBSD.org>2012-04-14 14:01:31 +0000
committerDimitry Andric <dim@FreeBSD.org>2012-04-14 14:01:31 +0000
commitdbe13110f59f48b4dbb7552b3ac2935acdeece7f (patch)
treebe1815eb79b42ff482a8562b13c2dcbf0c5dcbee /lib/Analysis/ThreadSafety.cpp
parent9da628931ebf2609493570f87824ca22402cc65f (diff)
downloadsrc-dbe13110f59f48b4dbb7552b3ac2935acdeece7f.tar.gz
src-dbe13110f59f48b4dbb7552b3ac2935acdeece7f.zip
Vendor import of clang trunk r154661:vendor/clang/clang-trunk-r154661
Notes
Notes: svn path=/vendor/clang/dist/; revision=234287 svn path=/vendor/clang/clang-trunk-r154661/; revision=234288; tag=vendor/clang/clang-trunk-r154661
Diffstat (limited to 'lib/Analysis/ThreadSafety.cpp')
-rw-r--r--lib/Analysis/ThreadSafety.cpp1533
1 files changed, 1230 insertions, 303 deletions
diff --git a/lib/Analysis/ThreadSafety.cpp b/lib/Analysis/ThreadSafety.cpp
index 5a12913c1c94..2f7e794c2b38 100644
--- a/lib/Analysis/ThreadSafety.cpp
+++ b/lib/Analysis/ThreadSafety.cpp
@@ -16,6 +16,7 @@
//===----------------------------------------------------------------------===//
#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"
@@ -31,7 +32,9 @@
#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;
@@ -40,90 +43,7 @@ using namespace thread_safety;
// Key method definition
ThreadSafetyHandler::~ThreadSafetyHandler() {}
-// Helper function
-static Expr *getParent(Expr *Exp) {
- if (MemberExpr *ME = dyn_cast<MemberExpr>(Exp))
- return ME->getBase();
- if (CXXMemberCallExpr *CE = dyn_cast<CXXMemberCallExpr>(Exp))
- return CE->getImplicitObjectArgument();
- return 0;
-}
-
namespace {
-/// \brief Implements a set of CFGBlocks using a BitVector.
-///
-/// This class contains a minimal interface, primarily dictated by the SetType
-/// template parameter of the llvm::po_iterator template, as used with external
-/// storage. We also use this set to keep track of which CFGBlocks we visit
-/// during the analysis.
-class CFGBlockSet {
- llvm::BitVector VisitedBlockIDs;
-
-public:
- // po_iterator requires this iterator, but the only interface needed is the
- // value_type typedef.
- struct iterator {
- typedef const CFGBlock *value_type;
- };
-
- CFGBlockSet() {}
- CFGBlockSet(const CFG *G) : VisitedBlockIDs(G->getNumBlockIDs(), false) {}
-
- /// \brief Set the bit associated with a particular CFGBlock.
- /// This is the important method for the SetType template parameter.
- bool insert(const CFGBlock *Block) {
- // Note that insert() is called by po_iterator, which doesn't check to make
- // sure that Block is non-null. Moreover, the CFGBlock iterator will
- // occasionally hand out null pointers for pruned edges, so we catch those
- // here.
- if (Block == 0)
- return false; // if an edge is trivially false.
- if (VisitedBlockIDs.test(Block->getBlockID()))
- return false;
- VisitedBlockIDs.set(Block->getBlockID());
- return true;
- }
-
- /// \brief Check if the bit for a CFGBlock has been already set.
- /// This method is for tracking visited blocks in the main threadsafety loop.
- /// Block must not be null.
- bool alreadySet(const CFGBlock *Block) {
- return VisitedBlockIDs.test(Block->getBlockID());
- }
-};
-
-/// \brief We create a helper class which we use to iterate through CFGBlocks in
-/// the topological order.
-class TopologicallySortedCFG {
- typedef llvm::po_iterator<const CFG*, CFGBlockSet, true> po_iterator;
-
- std::vector<const CFGBlock*> Blocks;
-
-public:
- typedef std::vector<const CFGBlock*>::reverse_iterator iterator;
-
- TopologicallySortedCFG(const CFG *CFGraph) {
- Blocks.reserve(CFGraph->getNumBlockIDs());
- CFGBlockSet BSet(CFGraph);
-
- for (po_iterator I = po_iterator::begin(CFGraph, BSet),
- E = po_iterator::end(CFGraph, BSet); I != E; ++I) {
- Blocks.push_back(*I);
- }
- }
-
- iterator begin() {
- return Blocks.rbegin();
- }
-
- iterator end() {
- return Blocks.rend();
- }
-
- bool empty() {
- return begin() == end();
- }
-};
/// \brief A MutexID object uniquely identifies a particular mutex, and
/// is built from an Expr* (i.e. calling a lock function).
@@ -136,16 +56,17 @@ public:
/// (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 set of named
+/// 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.
+/// 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.
@@ -164,38 +85,176 @@ class MutexID {
SmallVector<NamedDecl*, 2> DeclSeq;
/// Build a Decl sequence representing the lock from the given expression.
- /// Recursive function that bottoms out when the final DeclRefExpr is reached.
- // FIXME: Lock expressions that involve array indices or function calls.
- // FIXME: Deal with LockReturned attribute.
- void buildMutexID(Expr *Exp, Expr *Parent) {
+ /// 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, const NamedDecl *D, Expr *Parent,
+ unsigned NumArgs, Expr **FunArgs) {
+ 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 (FunArgs && FD == D->getCanonicalDecl()) {
+ // Substitute call arguments for references to function parameters
+ assert(i < NumArgs);
+ buildMutexID(FunArgs[i], D, 0, 0, 0);
+ 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 (MemberExpr *ME = dyn_cast<MemberExpr>(Exp)) {
NamedDecl *ND = ME->getMemberDecl();
DeclSeq.push_back(ND);
- buildMutexID(ME->getBase(), Parent);
+ buildMutexID(ME->getBase(), D, Parent, NumArgs, FunArgs);
} else if (isa<CXXThisExpr>(Exp)) {
if (Parent)
- buildMutexID(Parent, 0);
- else
- return; // mutexID is still valid in this case
- } else if (CastExpr *CE = dyn_cast<CastExpr>(Exp))
- buildMutexID(CE->getSubExpr(), Parent);
- else
- DeclSeq.clear(); // invalid lock expression
+ buildMutexID(Parent, D, 0, 0, 0);
+ else {
+ DeclSeq.push_back(0); // Use 0 to represent 'this'.
+ return; // mutexID is still valid in this case
+ }
+ } else if (CXXMemberCallExpr *CMCE = dyn_cast<CXXMemberCallExpr>(Exp)) {
+ DeclSeq.push_back(CMCE->getMethodDecl()->getCanonicalDecl());
+ buildMutexID(CMCE->getImplicitObjectArgument(),
+ D, Parent, NumArgs, FunArgs);
+ unsigned NumCallArgs = CMCE->getNumArgs();
+ Expr** CallArgs = CMCE->getArgs();
+ for (unsigned i = 0; i < NumCallArgs; ++i) {
+ buildMutexID(CallArgs[i], D, Parent, NumArgs, FunArgs);
+ }
+ } else if (CallExpr *CE = dyn_cast<CallExpr>(Exp)) {
+ buildMutexID(CE->getCallee(), D, Parent, NumArgs, FunArgs);
+ unsigned NumCallArgs = CE->getNumArgs();
+ Expr** CallArgs = CE->getArgs();
+ for (unsigned i = 0; i < NumCallArgs; ++i) {
+ buildMutexID(CallArgs[i], D, Parent, NumArgs, FunArgs);
+ }
+ } else if (BinaryOperator *BOE = dyn_cast<BinaryOperator>(Exp)) {
+ buildMutexID(BOE->getLHS(), D, Parent, NumArgs, FunArgs);
+ buildMutexID(BOE->getRHS(), D, Parent, NumArgs, FunArgs);
+ } else if (UnaryOperator *UOE = dyn_cast<UnaryOperator>(Exp)) {
+ buildMutexID(UOE->getSubExpr(), D, Parent, NumArgs, FunArgs);
+ } else if (ArraySubscriptExpr *ASE = dyn_cast<ArraySubscriptExpr>(Exp)) {
+ buildMutexID(ASE->getBase(), D, Parent, NumArgs, FunArgs);
+ buildMutexID(ASE->getIdx(), D, Parent, NumArgs, FunArgs);
+ } else if (AbstractConditionalOperator *CE =
+ dyn_cast<AbstractConditionalOperator>(Exp)) {
+ buildMutexID(CE->getCond(), D, Parent, NumArgs, FunArgs);
+ buildMutexID(CE->getTrueExpr(), D, Parent, NumArgs, FunArgs);
+ buildMutexID(CE->getFalseExpr(), D, Parent, NumArgs, FunArgs);
+ } else if (ChooseExpr *CE = dyn_cast<ChooseExpr>(Exp)) {
+ buildMutexID(CE->getCond(), D, Parent, NumArgs, FunArgs);
+ buildMutexID(CE->getLHS(), D, Parent, NumArgs, FunArgs);
+ buildMutexID(CE->getRHS(), D, Parent, NumArgs, FunArgs);
+ } else if (CastExpr *CE = dyn_cast<CastExpr>(Exp)) {
+ buildMutexID(CE->getSubExpr(), D, Parent, NumArgs, FunArgs);
+ } else if (ParenExpr *PE = dyn_cast<ParenExpr>(Exp)) {
+ buildMutexID(PE->getSubExpr(), D, Parent, NumArgs, FunArgs);
+ } 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) {
+ Expr *Parent = 0;
+ unsigned NumArgs = 0;
+ Expr **FunArgs = 0;
+
+ // If we are processing a raw attribute expression, with no substitutions.
+ if (DeclExp == 0) {
+ buildMutexID(MutexExp, D, 0, 0, 0);
+ return;
+ }
+
+ // Examine DeclExp to find Parent and FunArgs, which are used to substitute
+ // for formal parameters when we call buildMutexID later.
+ if (MemberExpr *ME = dyn_cast<MemberExpr>(DeclExp)) {
+ Parent = ME->getBase();
+ } else if (CXXMemberCallExpr *CE = dyn_cast<CXXMemberCallExpr>(DeclExp)) {
+ Parent = CE->getImplicitObjectArgument();
+ NumArgs = CE->getNumArgs();
+ FunArgs = CE->getArgs();
+ } else if (CallExpr *CE = dyn_cast<CallExpr>(DeclExp)) {
+ NumArgs = CE->getNumArgs();
+ FunArgs = CE->getArgs();
+ } else if (CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(DeclExp)) {
+ Parent = 0; // FIXME -- get the parent from DeclStmt
+ NumArgs = CE->getNumArgs();
+ FunArgs = CE->getArgs();
+ } else if (D && isa<CXXDestructorDecl>(D)) {
+ // There's no such thing as a "destructor call" in the AST.
+ Parent = DeclExp;
+ }
+
+ // If the attribute has no arguments, then assume the argument is "this".
+ if (MutexExp == 0) {
+ buildMutexID(Parent, D, 0, 0, 0);
+ return;
+ }
+
+ buildMutexID(MutexExp, D, Parent, NumArgs, FunArgs);
}
public:
- MutexID(Expr *LExpr, Expr *ParentExpr) {
- buildMutexID(LExpr, ParentExpr);
+ explicit MutexID(clang::Decl::EmptyShell e) {
+ DeclSeq.clear();
}
- /// If we encounter part of a lock expression we cannot parse
+ /// \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;
}
@@ -218,9 +277,11 @@ public:
/// 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.
- StringRef getName() const {
+ std::string getName() const {
assert(isValid());
- return DeclSeq.front()->getName();
+ if (!DeclSeq.front())
+ return "this"; // Use 0 to represent 'this'.
+ return DeclSeq.front()->getNameAsString();
}
void Profile(llvm::FoldingSetNodeID &ID) const {
@@ -231,6 +292,7 @@ public:
}
};
+
/// \brief This is a helper class that stores info about the most recent
/// accquire of a Lock.
///
@@ -245,9 +307,14 @@ struct LockData {
///
/// FIXME: add support for re-entrant locking and lock up/downgrading
LockKind LKind;
+ MutexID UnderlyingMutex; // for ScopedLockable objects
LockData(SourceLocation AcquireLoc, LockKind LKind)
- : AcquireLoc(AcquireLoc), LKind(LKind) {}
+ : AcquireLoc(AcquireLoc), LKind(LKind), UnderlyingMutex(Decl::EmptyShell())
+ {}
+
+ LockData(SourceLocation AcquireLoc, LockKind LKind, const MutexID &Mu)
+ : AcquireLoc(AcquireLoc), LKind(LKind), UnderlyingMutex(Mu) {}
bool operator==(const LockData &other) const {
return AcquireLoc == other.AcquireLoc && LKind == other.LKind;
@@ -258,14 +325,567 @@ struct LockData {
}
void Profile(llvm::FoldingSetNodeID &ID) const {
- ID.AddInteger(AcquireLoc.getRawEncoding());
- ID.AddInteger(LKind);
- }
+ 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<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;
+
+ NamedDecl *Dec; // The original declaration for this variable.
+ 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(NamedDecl *D, Expr *E, Context C)
+ : Dec(D), Exp(E), Ref(0), Ctx(C)
+ { }
+
+ // Create reference to previous definition
+ VarDefinition(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(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.
+ Expr* lookupExpr(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;
+ }
+ 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) {
+ 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) {
+ 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(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(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(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(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(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) {
+ 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) {
+ 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) {
+ 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;
+
+public:
+ ThreadSafetyAnalyzer(ThreadSafetyHandler &H) : Handler(H) {}
+
+ Lockset intersectAndWarn(const CFGBlockInfo &Block1, CFGBlockSide Side1,
+ const CFGBlockInfo &Block2, CFGBlockSide Side2,
+ LockErrorKind LEK);
+
+ Lockset addLock(Lockset &LSet, Expr *MutexExp, const NamedDecl *D,
+ LockKind LK, SourceLocation Loc);
+
+ void runAnalysis(AnalysisDeclContext &AC);
+};
+
/// \brief We use this class to visit different types of expressions in
/// CFGBlocks, and build up the lockset.
@@ -273,32 +893,51 @@ typedef llvm::ImmutableMap<MutexID, LockData> Lockset;
/// 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;
+
ThreadSafetyHandler &Handler;
- Lockset LSet;
Lockset::Factory &LocksetFactory;
+ LocalVariableMap &LocalVarMap;
+
+ Lockset LSet;
+ LocalVariableMap::Context LVarCtx;
+ unsigned CtxIndex;
// Helper functions
- void removeLock(SourceLocation UnlockLoc, Expr *LockExp, Expr *Parent);
- void addLock(SourceLocation LockLoc, Expr *LockExp, Expr *Parent,
- LockKind LK);
+ void addLock(const MutexID &Mutex, const LockData &LDat);
+ void removeLock(const MutexID &Mutex, SourceLocation UnlockLoc);
+
+ template <class AttrType>
+ void addLocksToSet(LockKind LK, AttrType *Attr,
+ Expr *Exp, NamedDecl *D, VarDecl *VD = 0);
+ void removeLocksFromSet(UnlockFunctionAttr *Attr,
+ Expr *Exp, NamedDecl* FunDecl);
+
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);
template <class AttrType>
- void addLocksToSet(LockKind LK, Attr *Attr, CXXMemberCallExpr *Exp);
+ void addTrylock(LockKind LK, AttrType *Attr, Expr *Exp, NamedDecl *FunDecl,
+ const CFGBlock* PredBlock, const CFGBlock *CurrBlock,
+ Expr *BrE, bool Neg);
+ CallExpr* getTrylockCallExpr(Stmt *Cond, LocalVariableMap::Context C,
+ bool &Negate);
+ void handleTrylock(Stmt *Cond, const CFGBlock* PredBlock,
+ const CFGBlock *CurrBlock);
/// \brief Returns true if the lockset contains a lock, regardless of whether
/// the lock is held exclusively or shared.
- bool locksetContains(MutexID Lock) const {
+ 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(MutexID Lock, LockKind KindRequested) const {
+ bool locksetContains(const MutexID &Lock, LockKind KindRequested) const {
const LockData *LockHeld = LSet.lookup(Lock);
return (LockHeld && KindRequested == LockHeld->LKind);
}
@@ -307,7 +946,8 @@ class BuildLockset : public StmtVisitor<BuildLockset> {
/// 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(MutexID Lock, LockKind KindRequested) const {
+ bool locksetContainsAtLeast(const MutexID &Lock,
+ LockKind KindRequested) const {
switch (KindRequested) {
case LK_Shared:
return locksetContains(Lock);
@@ -318,57 +958,121 @@ class BuildLockset : public StmtVisitor<BuildLockset> {
}
public:
- BuildLockset(ThreadSafetyHandler &Handler, Lockset LS, Lockset::Factory &F)
- : StmtVisitor<BuildLockset>(), Handler(Handler), LSet(LS),
- LocksetFactory(F) {}
-
- Lockset getLockset() {
- return LSet;
- }
+ BuildLockset(ThreadSafetyAnalyzer *analyzer, CFGBlockInfo &Info)
+ : StmtVisitor<BuildLockset>(),
+ Handler(analyzer->Handler),
+ LocksetFactory(analyzer->LocksetFactory),
+ LocalVarMap(analyzer->LocalVarMap),
+ LSet(Info.EntrySet),
+ LVarCtx(Info.EntryContext),
+ CtxIndex(Info.EntryIndex)
+ {}
void VisitUnaryOperator(UnaryOperator *UO);
void VisitBinaryOperator(BinaryOperator *BO);
void VisitCastExpr(CastExpr *CE);
- void VisitCXXMemberCallExpr(CXXMemberCallExpr *Exp);
+ void VisitCallExpr(CallExpr *Exp);
+ void VisitCXXConstructExpr(CXXConstructExpr *Exp);
+ void VisitDeclStmt(DeclStmt *S);
};
/// \brief Add a new lock to the lockset, warning if the lock is already there.
-/// \param LockLoc The source location of the acquire
-/// \param LockExp The lock expression corresponding to the lock to be added
-void BuildLockset::addLock(SourceLocation LockLoc, Expr *LockExp, Expr *Parent,
- LockKind LK) {
- // FIXME: deal with acquired before/after annotations. We can write a first
- // pass that does the transitive lookup lazily, and refine afterwards.
- MutexID Mutex(LockExp, Parent);
- if (!Mutex.isValid()) {
- Handler.handleInvalidLockExp(LockExp->getExprLoc());
- return;
- }
-
- LockData NewLock(LockLoc, LK);
-
+/// \param Mutex -- the Mutex expression for the lock
+/// \param LDat -- the LockData for the lock
+void BuildLockset::addLock(const MutexID &Mutex, const LockData& LDat) {
+ // FIXME: deal with acquired before/after annotations.
// FIXME: Don't always warn when we have support for reentrant locks.
if (locksetContains(Mutex))
- Handler.handleDoubleLock(Mutex.getName(), LockLoc);
- LSet = LocksetFactory.add(LSet, Mutex, NewLock);
+ Handler.handleDoubleLock(Mutex.getName(), LDat.AcquireLoc);
+ else
+ LSet = LocksetFactory.add(LSet, Mutex, LDat);
}
/// \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)
-void BuildLockset::removeLock(SourceLocation UnlockLoc, Expr *LockExp,
- Expr *Parent) {
- MutexID Mutex(LockExp, Parent);
- if (!Mutex.isValid()) {
- Handler.handleInvalidLockExp(LockExp->getExprLoc());
+void BuildLockset::removeLock(const MutexID &Mutex, SourceLocation UnlockLoc) {
+ const LockData *LDat = LSet.lookup(Mutex);
+ if (!LDat)
+ Handler.handleUnmatchedUnlock(Mutex.getName(), UnlockLoc);
+ else {
+ // For scoped-lockable vars, remove the mutex associated with this var.
+ if (LDat->UnderlyingMutex.isValid())
+ removeLock(LDat->UnderlyingMutex, UnlockLoc);
+ LSet = LocksetFactory.remove(LSet, 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>
+void BuildLockset::addLocksToSet(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);
+ else
+ addLock(Mutex, LockData(ExpLocation, LK));
return;
}
- Lockset NewLSet = LocksetFactory.remove(LSet, Mutex);
- if(NewLSet == LSet)
- Handler.handleUnmatchedUnlock(Mutex.getName(), UnlockLoc);
+ 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 {
+ addLock(Mutex, LockData(ExpLocation, LK));
+ if (isScopedVar) {
+ // 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);
+ addLock(SMutex, LockData(VD->getLocation(), LK, Mutex));
+ }
+ }
+ }
+}
- LSet = NewLSet;
+/// \brief This function removes a set of locks specified as attribute
+/// arguments from the lockset.
+void BuildLockset::removeLocksFromSet(UnlockFunctionAttr *Attr,
+ Expr *Exp, NamedDecl* FunDecl) {
+ SourceLocation ExpLocation;
+ if (Exp) ExpLocation = Exp->getExprLoc();
+
+ 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);
+ else
+ removeLock(Mu, ExpLocation);
+ return;
+ }
+
+ 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
+ removeLock(Mutex, ExpLocation);
+ }
}
/// \brief Gets the value decl pointer from DeclRefExprs or MemberExprs
@@ -383,20 +1087,19 @@ const ValueDecl *BuildLockset::getValueDecl(Expr *Exp) {
}
/// \brief Warn if the LSet does not contain a lock sufficient to protect access
-/// of at least the passed in AccessType.
+/// 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);
- Expr *Parent = getParent(Exp);
- MutexID Mutex(MutexExp, Parent);
+
+ MutexID Mutex(MutexExp, Exp, D);
if (!Mutex.isValid())
- Handler.handleInvalidLockExp(MutexExp->getExprLoc());
+ MutexID::warnInvalidLock(Handler, MutexExp, Exp, D);
else if (!locksetContainsAtLeast(Mutex, LK))
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.
@@ -440,71 +1143,10 @@ void BuildLockset::checkAccess(Expr *Exp, AccessKind AK) {
warnIfMutexNotHeld(D, Exp, AK, GBAttr->getArg(), POK_VarAccess);
}
-/// \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;
- 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);
-}
-
-/// \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>
-void BuildLockset::addLocksToSet(LockKind LK, Attr *Attr,
- CXXMemberCallExpr *Exp) {
- typedef typename AttrType::args_iterator iterator_type;
- SourceLocation ExpLocation = Exp->getExprLoc();
- Expr *Parent = Exp->getImplicitObjectArgument();
- AttrType *SpecificAttr = cast<AttrType>(Attr);
-
- if (SpecificAttr->args_size() == 0) {
- // The mutex held is the "this" object.
- addLock(ExpLocation, Parent, 0, LK);
- return;
- }
-
- for (iterator_type I = SpecificAttr->args_begin(),
- E = SpecificAttr->args_end(); I != E; ++I)
- addLock(ExpLocation, *I, Parent, LK);
-}
-
-/// \brief When visiting CXXMemberCallExprs we need to examine the attributes on
-/// the method that is being called and add, remove or check locks in the
-/// lockset accordingly.
+/// \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,
@@ -515,44 +1157,32 @@ void BuildLockset::addLocksToSet(LockKind LK, Attr *Attr,
///
/// FIXME: Do not flag an error for member variables accessed in constructors/
/// destructors
-void BuildLockset::VisitCXXMemberCallExpr(CXXMemberCallExpr *Exp) {
- NamedDecl *D = dyn_cast_or_null<NamedDecl>(Exp->getCalleeDecl());
-
- SourceLocation ExpLocation = Exp->getExprLoc();
- Expr *Parent = Exp->getImplicitObjectArgument();
-
- if(!D || !D->hasAttrs())
- return;
-
+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:
- addLocksToSet<ExclusiveLockFunctionAttr>(LK_Exclusive, Attr, Exp);
+ case attr::ExclusiveLockFunction: {
+ ExclusiveLockFunctionAttr *A = cast<ExclusiveLockFunctionAttr>(Attr);
+ addLocksToSet(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:
- addLocksToSet<SharedLockFunctionAttr>(LK_Shared, Attr, Exp);
+ case attr::SharedLockFunction: {
+ SharedLockFunctionAttr *A = cast<SharedLockFunctionAttr>(Attr);
+ addLocksToSet(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);
-
- if (UFAttr->args_size() == 0) { // The lock held is the "this" object.
- removeLock(ExpLocation, Parent, 0);
- break;
- }
-
- for (UnlockFunctionAttr::args_iterator I = UFAttr->args_begin(),
- E = UFAttr->args_end(); I != E; ++I)
- removeLock(ExpLocation, *I, Parent);
+ removeLocksFromSet(UFAttr, Exp, D);
break;
}
@@ -579,12 +1209,12 @@ void BuildLockset::VisitCXXMemberCallExpr(CXXMemberCallExpr *Exp) {
LocksExcludedAttr *LEAttr = cast<LocksExcludedAttr>(Attr);
for (LocksExcludedAttr::args_iterator I = LEAttr->args_begin(),
E = LEAttr->args_end(); I != E; ++I) {
- MutexID Mutex(*I, Parent);
+ MutexID Mutex(*I, Exp, D);
if (!Mutex.isValid())
- Handler.handleInvalidLockExp((*I)->getExprLoc());
+ MutexID::warnInvalidLock(Handler, *I, Exp, D);
else if (locksetContains(Mutex))
Handler.handleFunExcludesLock(D->getName(), Mutex.getName(),
- ExpLocation);
+ Exp->getExprLoc());
}
break;
}
@@ -596,7 +1226,180 @@ void BuildLockset::VisitCXXMemberCallExpr(CXXMemberCallExpr *Exp) {
}
}
-} // end anonymous namespace
+
+/// \brief Add lock to set, if the current block is in the taken branch of a
+/// trylock.
+template <class AttrType>
+void BuildLockset::addTrylock(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;
+
+ // 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) {
+ addLocksToSet(LK, Attr, Exp, FunDecl, 0);
+ }
+ }
+}
+
+
+// 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(...))
+CallExpr* BuildLockset::getTrylockCallExpr(Stmt *Cond,
+ LocalVariableMap::Context C,
+ bool &Negate) {
+ if (!Cond)
+ return 0;
+
+ if (CallExpr *CallExp = dyn_cast<CallExpr>(Cond)) {
+ return CallExp;
+ }
+ else if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(Cond)) {
+ return getTrylockCallExpr(CE->getSubExpr(), C, Negate);
+ }
+ else if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Cond)) {
+ Expr *E = LocalVarMap.lookupExpr(DRE->getDecl(), C);
+ return getTrylockCallExpr(E, C, Negate);
+ }
+ else if (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 Process a conditional branch from a previous block to the current
+/// block, looking for trylock calls.
+void BuildLockset::handleTrylock(Stmt *Cond, const CFGBlock *PredBlock,
+ const CFGBlock *CurrBlock) {
+ bool Negate = false;
+ CallExpr *Exp = getTrylockCallExpr(Cond, LVarCtx, Negate);
+ if (!Exp)
+ return;
+
+ NamedDecl *FunDecl = dyn_cast_or_null<NamedDecl>(Exp->getCalleeDecl());
+ if(!FunDecl || !FunDecl->hasAttrs())
+ return;
+
+ // 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);
+ addTrylock(LK_Exclusive, A, Exp, FunDecl, PredBlock, CurrBlock,
+ A->getSuccessValue(), Negate);
+ break;
+ }
+ case attr::SharedTrylockFunction: {
+ SharedTrylockFunctionAttr *A =
+ cast<SharedTrylockFunctionAttr>(Attr);
+ addTrylock(LK_Shared, A, Exp, FunDecl, PredBlock, CurrBlock,
+ A->getSuccessValue(), Negate);
+ break;
+ }
+ 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 = 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 = 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.
@@ -606,9 +1409,14 @@ void BuildLockset::VisitCXXMemberCallExpr(CXXMemberCallExpr *Exp) {
/// 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.
-static Lockset intersectAndWarn(ThreadSafetyHandler &Handler,
- const Lockset LSet1, const Lockset LSet2,
- Lockset::Factory &Fact, LockErrorKind LEK) {
+Lockset ThreadSafetyAnalyzer::intersectAndWarn(const CFGBlockInfo &Block1,
+ CFGBlockSide Side1,
+ const CFGBlockInfo &Block2,
+ CFGBlockSide Side2,
+ LockErrorKind LEK) {
+ Lockset LSet1 = Block1.getSet(Side1);
+ Lockset LSet2 = Block2.getSet(Side2);
+
Lockset Intersection = LSet1;
for (Lockset::iterator I = LSet2.begin(), E = LSet2.end(); I != E; ++I) {
const MutexID &LSet2Mutex = I.getKey();
@@ -619,11 +1427,13 @@ static Lockset intersectAndWarn(ThreadSafetyHandler &Handler,
LSet2LockData.AcquireLoc,
LD->AcquireLoc);
if (LD->LKind != LK_Exclusive)
- Intersection = Fact.add(Intersection, LSet2Mutex, LSet2LockData);
+ Intersection = LocksetFactory.add(Intersection, LSet2Mutex,
+ LSet2LockData);
}
} else {
Handler.handleMutexHeldEndOfScope(LSet2Mutex.getName(),
- LSet2LockData.AcquireLoc, LEK);
+ LSet2LockData.AcquireLoc,
+ Block1.getLocation(Side1), LEK);
}
}
@@ -632,91 +1442,111 @@ static Lockset intersectAndWarn(ThreadSafetyHandler &Handler,
const MutexID &Mutex = I.getKey();
const LockData &MissingLock = I.getData();
Handler.handleMutexHeldEndOfScope(Mutex.getName(),
- MissingLock.AcquireLoc, LEK);
- Intersection = Fact.remove(Intersection, Mutex);
+ MissingLock.AcquireLoc,
+ Block2.getLocation(Side2), LEK);
+ Intersection = LocksetFactory.remove(Intersection, Mutex);
}
}
return Intersection;
}
-static Lockset addLock(ThreadSafetyHandler &Handler,
- Lockset::Factory &LocksetFactory,
- Lockset &LSet, Expr *LockExp, LockKind LK,
- SourceLocation Loc) {
- MutexID Mutex(LockExp, 0);
+Lockset ThreadSafetyAnalyzer::addLock(Lockset &LSet, Expr *MutexExp,
+ const NamedDecl *D,
+ LockKind LK, SourceLocation Loc) {
+ MutexID Mutex(MutexExp, 0, D);
if (!Mutex.isValid()) {
- Handler.handleInvalidLockExp(LockExp->getExprLoc());
+ MutexID::warnInvalidLock(Handler, MutexExp, 0, D);
return LSet;
}
LockData NewLock(Loc, LK);
return LocksetFactory.add(LSet, Mutex, NewLock);
}
-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(AnalysisContext &AC,
- ThreadSafetyHandler &Handler) {
+void ThreadSafetyAnalyzer::runAnalysis(AnalysisDeclContext &AC) {
CFG *CFGraph = AC.getCFG();
if (!CFGraph) return;
- const Decl *D = AC.getDecl();
- if (D && D->getAttr<NoThreadSafetyAnalysisAttr>()) return;
+ const NamedDecl *D = dyn_cast_or_null<NamedDecl>(AC.getDecl());
- Lockset::Factory LocksetFactory;
-
- // FIXME: Swith to SmallVector? Otherwise improve performance impact?
- std::vector<Lockset> EntryLocksets(CFGraph->getNumBlockIDs(),
- LocksetFactory.getEmptyMap());
- std::vector<Lockset> ExitLocksets(CFGraph->getNumBlockIDs(),
- LocksetFactory.getEmptyMap());
+ 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.
+
+ std::vector<CFGBlockInfo> BlockInfo(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.
- TopologicallySortedCFG SortedGraph(CFGraph);
- CFGBlockSet VisitedBlocks(CFGraph);
+ 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);
- if (!SortedGraph.empty() && D->hasAttrs()) {
- const CFGBlock *FirstBlock = *SortedGraph.begin();
- Lockset &InitialLockset = EntryLocksets[FirstBlock->getBlockID()];
+ // 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) {
+ 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(Handler, LocksetFactory, InitialLockset,
- *SLRIter, LK_Shared,
+ SLRIter = SLRAttr->args_begin(),
+ SLREnd = SLRAttr->args_end(); SLRIter != SLREnd; ++SLRIter)
+ InitialLockset = addLock(InitialLockset,
+ *SLRIter, D, LK_Shared,
AttrLoc);
} 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(Handler, LocksetFactory, InitialLockset,
- *ELRIter, LK_Exclusive,
+ ELRIter = ELRAttr->args_begin(),
+ ELREnd = ELRAttr->args_end(); ELRIter != ELREnd; ++ELRIter)
+ InitialLockset = addLock(InitialLockset,
+ *ELRIter, D, LK_Exclusive,
AttrLoc);
+ } 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;
}
}
}
- for (TopologicallySortedCFG::iterator I = SortedGraph.begin(),
- E = SortedGraph.end(); I!= E; ++I) {
+ for (PostOrderCFGView::iterator I = SortedGraph->begin(),
+ E = SortedGraph->end(); I!= E; ++I) {
const CFGBlock *CurrBlock = *I;
int CurrBlockID = CurrBlock->getBlockID();
-
- VisitedBlocks.insert(CurrBlock);
+ CFGBlockInfo *CurrBlockInfo = &BlockInfo[CurrBlockID];
// Use the default initial lockset in case there are no predecessors.
- Lockset &Entryset = EntryLocksets[CurrBlockID];
- Lockset &Exitset = ExitLocksets[CurrBlockID];
+ 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
@@ -732,6 +1562,7 @@ void runThreadSafetyAnalysis(AnalysisContext &AC,
// 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) {
@@ -739,24 +1570,102 @@ void runThreadSafetyAnalysis(AnalysisContext &AC,
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];
+
if (!LocksetInitialized) {
- Entryset = ExitLocksets[PrevBlockID];
+ CurrBlockInfo->EntrySet = PrevBlockInfo->ExitSet;
LocksetInitialized = true;
} else {
- Entryset = intersectAndWarn(Handler, Entryset,
- ExitLocksets[PrevBlockID], LocksetFactory,
- LEK_LockedSomePredecessors);
+ CurrBlockInfo->EntrySet =
+ intersectAndWarn(*CurrBlockInfo, CBS_Entry,
+ *PrevBlockInfo, CBS_Exit,
+ LEK_LockedSomePredecessors);
}
}
- BuildLockset LocksetBuilder(Handler, Entryset, LocksetFactory);
+ // 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);
+
+ // Do not update EntrySet.
+ intersectAndWarn(*CurrBlockInfo, CBS_Entry, *PrevBlockInfo, CBS_Exit,
+ IsLoop ? LEK_LockedSomeLoopIterations
+ : LEK_LockedSomePredecessors);
+ }
+ }
+
+ BuildLockset LocksetBuilder(this, *CurrBlockInfo);
+ CFGBlock::const_pred_iterator PI = CurrBlock->pred_begin(),
+ PE = CurrBlock->pred_end();
+ if (PI != PE) {
+ // If the predecessor ended in a branch, then process any trylocks.
+ // FIXME -- check to make sure there's only one predecessor.
+ if (Stmt *TCE = (*PI)->getTerminatorCondition()) {
+ LocksetBuilder.handleTrylock(TCE, *PI, CurrBlock);
+ }
+ }
+
+ // Visit all the statements in the basic block.
for (CFGBlock::const_iterator BI = CurrBlock->begin(),
BE = CurrBlock->end(); BI != BE; ++BI) {
- if (const CFGStmt *CfgStmt = dyn_cast<CFGStmt>(&*BI))
- LocksetBuilder.Visit(const_cast<Stmt*>(CfgStmt->getStmt()));
+ 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;
+ }
}
- Exitset = LocksetBuilder.getLockset();
+ 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
@@ -770,21 +1679,38 @@ void runThreadSafetyAnalysis(AnalysisContext &AC,
continue;
CFGBlock *FirstLoopBlock = *SI;
- Lockset PreLoop = EntryLocksets[FirstLoopBlock->getBlockID()];
- Lockset LoopEnd = ExitLocksets[CurrBlockID];
- intersectAndWarn(Handler, LoopEnd, PreLoop, LocksetFactory,
+ CFGBlockInfo &PreLoop = BlockInfo[FirstLoopBlock->getBlockID()];
+ CFGBlockInfo &LoopEnd = BlockInfo[CurrBlockID];
+ intersectAndWarn(LoopEnd, CBS_Exit, PreLoop, CBS_Entry,
LEK_LockedSomeLoopIterations);
}
}
- Lockset InitialLockset = EntryLocksets[CFGraph->getEntry().getBlockID()];
- Lockset FinalLockset = ExitLocksets[CFGraph->getExit().getBlockID()];
+ 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(Handler, InitialLockset, FinalLockset, LocksetFactory,
+ intersectAndWarn(Initial, CBS_Entry, Final, CBS_Exit,
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) {
@@ -796,4 +1722,5 @@ LockKind getLockKindFromAccessKind(AccessKind AK) {
}
llvm_unreachable("Unknown AccessKind");
}
+
}} // end namespace clang::thread_safety