ea70eb30a0
Required to pull some functions out of line, but this shouldn't have a perf impact. No functionality change. llvm-svn: 169092
2463 lines
88 KiB
C++
2463 lines
88 KiB
C++
//===- ThreadSafety.cpp ----------------------------------------*- C++ --*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// A intra-procedural analysis for thread safety (e.g. deadlocks and race
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// conditions), based off of an annotation system.
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//
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// See http://clang.llvm.org/docs/LanguageExtensions.html#threadsafety for more
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// information.
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//
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//===----------------------------------------------------------------------===//
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#include "clang/Analysis/Analyses/ThreadSafety.h"
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#include "clang/Analysis/Analyses/PostOrderCFGView.h"
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#include "clang/Analysis/AnalysisContext.h"
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#include "clang/Analysis/CFG.h"
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#include "clang/Analysis/CFGStmtMap.h"
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#include "clang/AST/Attr.h"
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#include "clang/AST/DeclCXX.h"
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#include "clang/AST/ExprCXX.h"
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#include "clang/AST/StmtCXX.h"
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#include "clang/AST/StmtVisitor.h"
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#include "clang/Basic/OperatorKinds.h"
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#include "clang/Basic/SourceLocation.h"
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#include "clang/Basic/SourceManager.h"
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#include "llvm/ADT/BitVector.h"
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#include "llvm/ADT/FoldingSet.h"
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#include "llvm/ADT/ImmutableMap.h"
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#include "llvm/ADT/PostOrderIterator.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/ADT/StringRef.h"
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#include "llvm/Support/raw_ostream.h"
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#include <algorithm>
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#include <utility>
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#include <vector>
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using namespace clang;
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using namespace thread_safety;
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// Key method definition
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ThreadSafetyHandler::~ThreadSafetyHandler() {}
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namespace {
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/// SExpr implements a simple expression language that is used to store,
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/// compare, and pretty-print C++ expressions. Unlike a clang Expr, a SExpr
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/// does not capture surface syntax, and it does not distinguish between
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/// C++ concepts, like pointers and references, that have no real semantic
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/// differences. This simplicity allows SExprs to be meaningfully compared,
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/// e.g.
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/// (x) = x
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/// (*this).foo = this->foo
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/// *&a = a
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///
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/// Thread-safety analysis works by comparing lock expressions. Within the
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/// body of a function, an expression such as "x->foo->bar.mu" will resolve to
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/// a particular mutex object at run-time. Subsequent occurrences of the same
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/// expression (where "same" means syntactic equality) will refer to the same
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/// run-time object if three conditions hold:
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/// (1) Local variables in the expression, such as "x" have not changed.
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/// (2) Values on the heap that affect the expression have not changed.
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/// (3) The expression involves only pure function calls.
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///
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/// The current implementation assumes, but does not verify, that multiple uses
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/// of the same lock expression satisfies these criteria.
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class SExpr {
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private:
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enum ExprOp {
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EOP_Nop, ///< No-op
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EOP_Wildcard, ///< Matches anything.
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EOP_Universal, ///< Universal lock.
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EOP_This, ///< This keyword.
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EOP_NVar, ///< Named variable.
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EOP_LVar, ///< Local variable.
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EOP_Dot, ///< Field access
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EOP_Call, ///< Function call
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EOP_MCall, ///< Method call
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EOP_Index, ///< Array index
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EOP_Unary, ///< Unary operation
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EOP_Binary, ///< Binary operation
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EOP_Unknown ///< Catchall for everything else
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};
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class SExprNode {
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private:
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unsigned char Op; ///< Opcode of the root node
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unsigned char Flags; ///< Additional opcode-specific data
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unsigned short Sz; ///< Number of child nodes
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const void* Data; ///< Additional opcode-specific data
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public:
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SExprNode(ExprOp O, unsigned F, const void* D)
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: Op(static_cast<unsigned char>(O)),
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Flags(static_cast<unsigned char>(F)), Sz(1), Data(D)
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{ }
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unsigned size() const { return Sz; }
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void setSize(unsigned S) { Sz = S; }
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ExprOp kind() const { return static_cast<ExprOp>(Op); }
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const NamedDecl* getNamedDecl() const {
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assert(Op == EOP_NVar || Op == EOP_LVar || Op == EOP_Dot);
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return reinterpret_cast<const NamedDecl*>(Data);
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}
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const NamedDecl* getFunctionDecl() const {
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assert(Op == EOP_Call || Op == EOP_MCall);
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return reinterpret_cast<const NamedDecl*>(Data);
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}
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bool isArrow() const { return Op == EOP_Dot && Flags == 1; }
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void setArrow(bool A) { Flags = A ? 1 : 0; }
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unsigned arity() const {
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switch (Op) {
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case EOP_Nop: return 0;
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case EOP_Wildcard: return 0;
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case EOP_Universal: return 0;
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case EOP_NVar: return 0;
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case EOP_LVar: return 0;
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case EOP_This: return 0;
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case EOP_Dot: return 1;
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case EOP_Call: return Flags+1; // First arg is function.
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case EOP_MCall: return Flags+1; // First arg is implicit obj.
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case EOP_Index: return 2;
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case EOP_Unary: return 1;
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case EOP_Binary: return 2;
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case EOP_Unknown: return Flags;
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}
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return 0;
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}
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bool operator==(const SExprNode& Other) const {
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// Ignore flags and size -- they don't matter.
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return (Op == Other.Op &&
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Data == Other.Data);
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}
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bool operator!=(const SExprNode& Other) const {
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return !(*this == Other);
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}
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bool matches(const SExprNode& Other) const {
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return (*this == Other) ||
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(Op == EOP_Wildcard) ||
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(Other.Op == EOP_Wildcard);
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}
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};
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/// \brief Encapsulates the lexical context of a function call. The lexical
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/// context includes the arguments to the call, including the implicit object
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/// argument. When an attribute containing a mutex expression is attached to
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/// a method, the expression may refer to formal parameters of the method.
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/// Actual arguments must be substituted for formal parameters to derive
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/// the appropriate mutex expression in the lexical context where the function
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/// is called. PrevCtx holds the context in which the arguments themselves
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/// should be evaluated; multiple calling contexts can be chained together
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/// by the lock_returned attribute.
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struct CallingContext {
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const NamedDecl* AttrDecl; // The decl to which the attribute is attached.
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Expr* SelfArg; // Implicit object argument -- e.g. 'this'
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bool SelfArrow; // is Self referred to with -> or .?
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unsigned NumArgs; // Number of funArgs
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Expr** FunArgs; // Function arguments
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CallingContext* PrevCtx; // The previous context; or 0 if none.
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CallingContext(const NamedDecl *D = 0, Expr *S = 0,
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unsigned N = 0, Expr **A = 0, CallingContext *P = 0)
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: AttrDecl(D), SelfArg(S), SelfArrow(false),
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NumArgs(N), FunArgs(A), PrevCtx(P)
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{ }
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};
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typedef SmallVector<SExprNode, 4> NodeVector;
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private:
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// A SExpr is a list of SExprNodes in prefix order. The Size field allows
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// the list to be traversed as a tree.
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NodeVector NodeVec;
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private:
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unsigned makeNop() {
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NodeVec.push_back(SExprNode(EOP_Nop, 0, 0));
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return NodeVec.size()-1;
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}
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unsigned makeWildcard() {
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NodeVec.push_back(SExprNode(EOP_Wildcard, 0, 0));
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return NodeVec.size()-1;
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}
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unsigned makeUniversal() {
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NodeVec.push_back(SExprNode(EOP_Universal, 0, 0));
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return NodeVec.size()-1;
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}
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unsigned makeNamedVar(const NamedDecl *D) {
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NodeVec.push_back(SExprNode(EOP_NVar, 0, D));
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return NodeVec.size()-1;
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}
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unsigned makeLocalVar(const NamedDecl *D) {
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NodeVec.push_back(SExprNode(EOP_LVar, 0, D));
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return NodeVec.size()-1;
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}
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unsigned makeThis() {
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NodeVec.push_back(SExprNode(EOP_This, 0, 0));
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return NodeVec.size()-1;
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}
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unsigned makeDot(const NamedDecl *D, bool Arrow) {
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NodeVec.push_back(SExprNode(EOP_Dot, Arrow ? 1 : 0, D));
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return NodeVec.size()-1;
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}
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unsigned makeCall(unsigned NumArgs, const NamedDecl *D) {
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NodeVec.push_back(SExprNode(EOP_Call, NumArgs, D));
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return NodeVec.size()-1;
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}
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// Grab the very first declaration of virtual method D
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const CXXMethodDecl* getFirstVirtualDecl(const CXXMethodDecl *D) {
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while (true) {
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D = D->getCanonicalDecl();
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CXXMethodDecl::method_iterator I = D->begin_overridden_methods(),
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E = D->end_overridden_methods();
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if (I == E)
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return D; // Method does not override anything
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D = *I; // FIXME: this does not work with multiple inheritance.
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}
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return 0;
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}
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unsigned makeMCall(unsigned NumArgs, const CXXMethodDecl *D) {
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NodeVec.push_back(SExprNode(EOP_MCall, NumArgs, getFirstVirtualDecl(D)));
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return NodeVec.size()-1;
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}
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unsigned makeIndex() {
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NodeVec.push_back(SExprNode(EOP_Index, 0, 0));
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return NodeVec.size()-1;
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}
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unsigned makeUnary() {
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NodeVec.push_back(SExprNode(EOP_Unary, 0, 0));
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return NodeVec.size()-1;
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}
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unsigned makeBinary() {
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NodeVec.push_back(SExprNode(EOP_Binary, 0, 0));
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return NodeVec.size()-1;
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}
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unsigned makeUnknown(unsigned Arity) {
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NodeVec.push_back(SExprNode(EOP_Unknown, Arity, 0));
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return NodeVec.size()-1;
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}
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/// Build an SExpr from the given C++ expression.
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/// Recursive function that terminates on DeclRefExpr.
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/// Note: this function merely creates a SExpr; it does not check to
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/// ensure that the original expression is a valid mutex expression.
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///
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/// NDeref returns the number of Derefence and AddressOf operations
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/// preceeding the Expr; this is used to decide whether to pretty-print
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/// SExprs with . or ->.
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unsigned buildSExpr(Expr *Exp, CallingContext* CallCtx, int* NDeref = 0) {
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if (!Exp)
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return 0;
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if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Exp)) {
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NamedDecl *ND = cast<NamedDecl>(DRE->getDecl()->getCanonicalDecl());
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ParmVarDecl *PV = dyn_cast_or_null<ParmVarDecl>(ND);
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if (PV) {
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FunctionDecl *FD =
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cast<FunctionDecl>(PV->getDeclContext())->getCanonicalDecl();
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unsigned i = PV->getFunctionScopeIndex();
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if (CallCtx && CallCtx->FunArgs &&
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FD == CallCtx->AttrDecl->getCanonicalDecl()) {
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// Substitute call arguments for references to function parameters
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assert(i < CallCtx->NumArgs);
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return buildSExpr(CallCtx->FunArgs[i], CallCtx->PrevCtx, NDeref);
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}
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// Map the param back to the param of the original function declaration.
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makeNamedVar(FD->getParamDecl(i));
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return 1;
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}
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// Not a function parameter -- just store the reference.
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makeNamedVar(ND);
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return 1;
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} else if (isa<CXXThisExpr>(Exp)) {
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// Substitute parent for 'this'
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if (CallCtx && CallCtx->SelfArg) {
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if (!CallCtx->SelfArrow && NDeref)
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// 'this' is a pointer, but self is not, so need to take address.
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--(*NDeref);
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return buildSExpr(CallCtx->SelfArg, CallCtx->PrevCtx, NDeref);
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}
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else {
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makeThis();
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return 1;
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}
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} else if (MemberExpr *ME = dyn_cast<MemberExpr>(Exp)) {
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NamedDecl *ND = ME->getMemberDecl();
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int ImplicitDeref = ME->isArrow() ? 1 : 0;
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unsigned Root = makeDot(ND, false);
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unsigned Sz = buildSExpr(ME->getBase(), CallCtx, &ImplicitDeref);
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NodeVec[Root].setArrow(ImplicitDeref > 0);
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NodeVec[Root].setSize(Sz + 1);
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return Sz + 1;
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} else if (CXXMemberCallExpr *CMCE = dyn_cast<CXXMemberCallExpr>(Exp)) {
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// When calling a function with a lock_returned attribute, replace
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// the function call with the expression in lock_returned.
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CXXMethodDecl* MD =
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cast<CXXMethodDecl>(CMCE->getMethodDecl()->getMostRecentDecl());
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if (LockReturnedAttr* At = MD->getAttr<LockReturnedAttr>()) {
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CallingContext LRCallCtx(CMCE->getMethodDecl());
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LRCallCtx.SelfArg = CMCE->getImplicitObjectArgument();
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LRCallCtx.SelfArrow =
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dyn_cast<MemberExpr>(CMCE->getCallee())->isArrow();
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LRCallCtx.NumArgs = CMCE->getNumArgs();
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LRCallCtx.FunArgs = CMCE->getArgs();
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LRCallCtx.PrevCtx = CallCtx;
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return buildSExpr(At->getArg(), &LRCallCtx);
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}
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// Hack to treat smart pointers and iterators as pointers;
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// ignore any method named get().
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if (CMCE->getMethodDecl()->getNameAsString() == "get" &&
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CMCE->getNumArgs() == 0) {
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if (NDeref && dyn_cast<MemberExpr>(CMCE->getCallee())->isArrow())
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++(*NDeref);
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return buildSExpr(CMCE->getImplicitObjectArgument(), CallCtx, NDeref);
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}
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unsigned NumCallArgs = CMCE->getNumArgs();
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unsigned Root = makeMCall(NumCallArgs, CMCE->getMethodDecl());
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unsigned Sz = buildSExpr(CMCE->getImplicitObjectArgument(), CallCtx);
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Expr** CallArgs = CMCE->getArgs();
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for (unsigned i = 0; i < NumCallArgs; ++i) {
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Sz += buildSExpr(CallArgs[i], CallCtx);
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}
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NodeVec[Root].setSize(Sz + 1);
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return Sz + 1;
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} else if (CallExpr *CE = dyn_cast<CallExpr>(Exp)) {
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FunctionDecl* FD =
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cast<FunctionDecl>(CE->getDirectCallee()->getMostRecentDecl());
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if (LockReturnedAttr* At = FD->getAttr<LockReturnedAttr>()) {
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CallingContext LRCallCtx(CE->getDirectCallee());
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LRCallCtx.NumArgs = CE->getNumArgs();
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LRCallCtx.FunArgs = CE->getArgs();
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LRCallCtx.PrevCtx = CallCtx;
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return buildSExpr(At->getArg(), &LRCallCtx);
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}
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// Treat smart pointers and iterators as pointers;
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// ignore the * and -> operators.
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if (CXXOperatorCallExpr *OE = dyn_cast<CXXOperatorCallExpr>(CE)) {
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OverloadedOperatorKind k = OE->getOperator();
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if (k == OO_Star) {
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if (NDeref) ++(*NDeref);
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return buildSExpr(OE->getArg(0), CallCtx, NDeref);
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}
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else if (k == OO_Arrow) {
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return buildSExpr(OE->getArg(0), CallCtx, NDeref);
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}
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}
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unsigned NumCallArgs = CE->getNumArgs();
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unsigned Root = makeCall(NumCallArgs, 0);
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unsigned Sz = buildSExpr(CE->getCallee(), CallCtx);
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Expr** CallArgs = CE->getArgs();
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for (unsigned i = 0; i < NumCallArgs; ++i) {
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Sz += buildSExpr(CallArgs[i], CallCtx);
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}
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NodeVec[Root].setSize(Sz+1);
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return Sz+1;
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} else if (BinaryOperator *BOE = dyn_cast<BinaryOperator>(Exp)) {
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unsigned Root = makeBinary();
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unsigned Sz = buildSExpr(BOE->getLHS(), CallCtx);
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Sz += buildSExpr(BOE->getRHS(), CallCtx);
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NodeVec[Root].setSize(Sz);
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return Sz;
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} else if (UnaryOperator *UOE = dyn_cast<UnaryOperator>(Exp)) {
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// Ignore & and * operators -- they're no-ops.
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// However, we try to figure out whether the expression is a pointer,
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// so we can use . and -> appropriately in error messages.
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if (UOE->getOpcode() == UO_Deref) {
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if (NDeref) ++(*NDeref);
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return buildSExpr(UOE->getSubExpr(), CallCtx, NDeref);
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}
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if (UOE->getOpcode() == UO_AddrOf) {
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if (DeclRefExpr* DRE = dyn_cast<DeclRefExpr>(UOE->getSubExpr())) {
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if (DRE->getDecl()->isCXXInstanceMember()) {
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// This is a pointer-to-member expression, e.g. &MyClass::mu_.
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// We interpret this syntax specially, as a wildcard.
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unsigned Root = makeDot(DRE->getDecl(), false);
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makeWildcard();
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NodeVec[Root].setSize(2);
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return 2;
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}
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}
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if (NDeref) --(*NDeref);
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return buildSExpr(UOE->getSubExpr(), CallCtx, NDeref);
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}
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unsigned Root = makeUnary();
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unsigned Sz = buildSExpr(UOE->getSubExpr(), CallCtx);
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NodeVec[Root].setSize(Sz);
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return Sz;
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} else if (ArraySubscriptExpr *ASE = dyn_cast<ArraySubscriptExpr>(Exp)) {
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unsigned Root = makeIndex();
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unsigned Sz = buildSExpr(ASE->getBase(), CallCtx);
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Sz += buildSExpr(ASE->getIdx(), CallCtx);
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NodeVec[Root].setSize(Sz);
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return Sz;
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} else if (AbstractConditionalOperator *CE =
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dyn_cast<AbstractConditionalOperator>(Exp)) {
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unsigned Root = makeUnknown(3);
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unsigned Sz = buildSExpr(CE->getCond(), CallCtx);
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Sz += buildSExpr(CE->getTrueExpr(), CallCtx);
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Sz += buildSExpr(CE->getFalseExpr(), CallCtx);
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NodeVec[Root].setSize(Sz);
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return Sz;
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} else if (ChooseExpr *CE = dyn_cast<ChooseExpr>(Exp)) {
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unsigned Root = makeUnknown(3);
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unsigned Sz = buildSExpr(CE->getCond(), CallCtx);
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Sz += buildSExpr(CE->getLHS(), CallCtx);
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Sz += buildSExpr(CE->getRHS(), CallCtx);
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NodeVec[Root].setSize(Sz);
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return Sz;
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} else if (CastExpr *CE = dyn_cast<CastExpr>(Exp)) {
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return buildSExpr(CE->getSubExpr(), CallCtx, NDeref);
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} else if (ParenExpr *PE = dyn_cast<ParenExpr>(Exp)) {
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return buildSExpr(PE->getSubExpr(), CallCtx, NDeref);
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} else if (ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(Exp)) {
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return buildSExpr(EWC->getSubExpr(), CallCtx, NDeref);
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} else if (CXXBindTemporaryExpr *E = dyn_cast<CXXBindTemporaryExpr>(Exp)) {
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return buildSExpr(E->getSubExpr(), CallCtx, NDeref);
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} else if (isa<CharacterLiteral>(Exp) ||
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isa<CXXNullPtrLiteralExpr>(Exp) ||
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isa<GNUNullExpr>(Exp) ||
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isa<CXXBoolLiteralExpr>(Exp) ||
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isa<FloatingLiteral>(Exp) ||
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isa<ImaginaryLiteral>(Exp) ||
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isa<IntegerLiteral>(Exp) ||
|
|
isa<StringLiteral>(Exp) ||
|
|
isa<ObjCStringLiteral>(Exp)) {
|
|
makeNop();
|
|
return 1; // FIXME: Ignore literals for now
|
|
} else {
|
|
makeNop();
|
|
return 1; // Ignore. FIXME: mark as invalid expression?
|
|
}
|
|
}
|
|
|
|
/// \brief Construct a SExpr 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 buildSExprFromExpr(Expr *MutexExp, Expr *DeclExp, const NamedDecl *D,
|
|
VarDecl *SelfDecl = 0) {
|
|
CallingContext CallCtx(D);
|
|
|
|
if (MutexExp) {
|
|
if (StringLiteral* SLit = dyn_cast<StringLiteral>(MutexExp)) {
|
|
if (SLit->getString() == StringRef("*"))
|
|
// The "*" expr is a universal lock, which essentially turns off
|
|
// checks until it is removed from the lockset.
|
|
makeUniversal();
|
|
else
|
|
// Ignore other string literals for now.
|
|
makeNop();
|
|
return;
|
|
}
|
|
}
|
|
|
|
// If we are processing a raw attribute expression, with no substitutions.
|
|
if (DeclExp == 0) {
|
|
buildSExpr(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();
|
|
CallCtx.SelfArrow = ME->isArrow();
|
|
} else if (CXXMemberCallExpr *CE = dyn_cast<CXXMemberCallExpr>(DeclExp)) {
|
|
CallCtx.SelfArg = CE->getImplicitObjectArgument();
|
|
CallCtx.SelfArrow = dyn_cast<MemberExpr>(CE->getCallee())->isArrow();
|
|
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; // Will be set below
|
|
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;
|
|
}
|
|
|
|
// Hack to handle constructors, where self cannot be recovered from
|
|
// the expression.
|
|
if (SelfDecl && !CallCtx.SelfArg) {
|
|
DeclRefExpr SelfDRE(SelfDecl, false, SelfDecl->getType(), VK_LValue,
|
|
SelfDecl->getLocation());
|
|
CallCtx.SelfArg = &SelfDRE;
|
|
|
|
// If the attribute has no arguments, then assume the argument is "this".
|
|
if (MutexExp == 0)
|
|
buildSExpr(CallCtx.SelfArg, 0);
|
|
else // For most attributes.
|
|
buildSExpr(MutexExp, &CallCtx);
|
|
return;
|
|
}
|
|
|
|
// If the attribute has no arguments, then assume the argument is "this".
|
|
if (MutexExp == 0)
|
|
buildSExpr(CallCtx.SelfArg, 0);
|
|
else // For most attributes.
|
|
buildSExpr(MutexExp, &CallCtx);
|
|
}
|
|
|
|
/// \brief Get index of next sibling of node i.
|
|
unsigned getNextSibling(unsigned i) const {
|
|
return i + NodeVec[i].size();
|
|
}
|
|
|
|
public:
|
|
explicit SExpr(clang::Decl::EmptyShell e) { NodeVec.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.
|
|
SExpr(Expr* MutexExp, Expr *DeclExp, const NamedDecl* D,
|
|
VarDecl *SelfDecl=0) {
|
|
buildSExprFromExpr(MutexExp, DeclExp, D, SelfDecl);
|
|
}
|
|
|
|
/// Return true if this is a valid decl sequence.
|
|
/// Caller must call this by hand after construction to handle errors.
|
|
bool isValid() const {
|
|
return !NodeVec.empty();
|
|
}
|
|
|
|
bool shouldIgnore() const {
|
|
// Nop is a mutex that we have decided to deliberately ignore.
|
|
assert(NodeVec.size() > 0 && "Invalid Mutex");
|
|
return NodeVec[0].kind() == EOP_Nop;
|
|
}
|
|
|
|
bool isUniversal() const {
|
|
assert(NodeVec.size() > 0 && "Invalid Mutex");
|
|
return NodeVec[0].kind() == EOP_Universal;
|
|
}
|
|
|
|
/// 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 SExpr &other) const {
|
|
return NodeVec == other.NodeVec;
|
|
}
|
|
|
|
bool operator!=(const SExpr &other) const {
|
|
return !(*this == other);
|
|
}
|
|
|
|
bool matches(const SExpr &Other, unsigned i = 0, unsigned j = 0) const {
|
|
if (NodeVec[i].matches(Other.NodeVec[j])) {
|
|
unsigned ni = NodeVec[i].arity();
|
|
unsigned nj = Other.NodeVec[j].arity();
|
|
unsigned n = (ni < nj) ? ni : nj;
|
|
bool Result = true;
|
|
unsigned ci = i+1; // first child of i
|
|
unsigned cj = j+1; // first child of j
|
|
for (unsigned k = 0; k < n;
|
|
++k, ci=getNextSibling(ci), cj = Other.getNextSibling(cj)) {
|
|
Result = Result && matches(Other, ci, cj);
|
|
}
|
|
return Result;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
// A partial match between a.mu and b.mu returns true a and b have the same
|
|
// type (and thus mu refers to the same mutex declaration), regardless of
|
|
// whether a and b are different objects or not.
|
|
bool partiallyMatches(const SExpr &Other) const {
|
|
if (NodeVec[0].kind() == EOP_Dot)
|
|
return NodeVec[0].matches(Other.NodeVec[0]);
|
|
return false;
|
|
}
|
|
|
|
/// \brief Pretty print a lock expression for use in error messages.
|
|
std::string toString(unsigned i = 0) const {
|
|
assert(isValid());
|
|
if (i >= NodeVec.size())
|
|
return "";
|
|
|
|
const SExprNode* N = &NodeVec[i];
|
|
switch (N->kind()) {
|
|
case EOP_Nop:
|
|
return "_";
|
|
case EOP_Wildcard:
|
|
return "(?)";
|
|
case EOP_Universal:
|
|
return "*";
|
|
case EOP_This:
|
|
return "this";
|
|
case EOP_NVar:
|
|
case EOP_LVar: {
|
|
return N->getNamedDecl()->getNameAsString();
|
|
}
|
|
case EOP_Dot: {
|
|
if (NodeVec[i+1].kind() == EOP_Wildcard) {
|
|
std::string S = "&";
|
|
S += N->getNamedDecl()->getQualifiedNameAsString();
|
|
return S;
|
|
}
|
|
std::string FieldName = N->getNamedDecl()->getNameAsString();
|
|
if (NodeVec[i+1].kind() == EOP_This)
|
|
return FieldName;
|
|
|
|
std::string S = toString(i+1);
|
|
if (N->isArrow())
|
|
return S + "->" + FieldName;
|
|
else
|
|
return S + "." + FieldName;
|
|
}
|
|
case EOP_Call: {
|
|
std::string S = toString(i+1) + "(";
|
|
unsigned NumArgs = N->arity()-1;
|
|
unsigned ci = getNextSibling(i+1);
|
|
for (unsigned k=0; k<NumArgs; ++k, ci = getNextSibling(ci)) {
|
|
S += toString(ci);
|
|
if (k+1 < NumArgs) S += ",";
|
|
}
|
|
S += ")";
|
|
return S;
|
|
}
|
|
case EOP_MCall: {
|
|
std::string S = "";
|
|
if (NodeVec[i+1].kind() != EOP_This)
|
|
S = toString(i+1) + ".";
|
|
if (const NamedDecl *D = N->getFunctionDecl())
|
|
S += D->getNameAsString() + "(";
|
|
else
|
|
S += "#(";
|
|
unsigned NumArgs = N->arity()-1;
|
|
unsigned ci = getNextSibling(i+1);
|
|
for (unsigned k=0; k<NumArgs; ++k, ci = getNextSibling(ci)) {
|
|
S += toString(ci);
|
|
if (k+1 < NumArgs) S += ",";
|
|
}
|
|
S += ")";
|
|
return S;
|
|
}
|
|
case EOP_Index: {
|
|
std::string S1 = toString(i+1);
|
|
std::string S2 = toString(i+1 + NodeVec[i+1].size());
|
|
return S1 + "[" + S2 + "]";
|
|
}
|
|
case EOP_Unary: {
|
|
std::string S = toString(i+1);
|
|
return "#" + S;
|
|
}
|
|
case EOP_Binary: {
|
|
std::string S1 = toString(i+1);
|
|
std::string S2 = toString(i+1 + NodeVec[i+1].size());
|
|
return "(" + S1 + "#" + S2 + ")";
|
|
}
|
|
case EOP_Unknown: {
|
|
unsigned NumChildren = N->arity();
|
|
if (NumChildren == 0)
|
|
return "(...)";
|
|
std::string S = "(";
|
|
unsigned ci = i+1;
|
|
for (unsigned j = 0; j < NumChildren; ++j, ci = getNextSibling(ci)) {
|
|
S += toString(ci);
|
|
if (j+1 < NumChildren) S += "#";
|
|
}
|
|
S += ")";
|
|
return S;
|
|
}
|
|
}
|
|
return "";
|
|
}
|
|
};
|
|
|
|
|
|
|
|
/// \brief A short list of SExprs
|
|
class MutexIDList : public SmallVector<SExpr, 3> {
|
|
public:
|
|
/// \brief Return true if the list contains the specified SExpr
|
|
/// Performs a linear search, because these lists are almost always very small.
|
|
bool contains(const SExpr& M) {
|
|
for (iterator I=begin(),E=end(); I != E; ++I)
|
|
if ((*I) == M) return true;
|
|
return false;
|
|
}
|
|
|
|
/// \brief Push M onto list, bud discard duplicates
|
|
void push_back_nodup(const SExpr& M) {
|
|
if (!contains(M)) push_back(M);
|
|
}
|
|
};
|
|
|
|
|
|
|
|
/// \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
|
|
SExpr 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 SExpr &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);
|
|
}
|
|
|
|
bool isAtLeast(LockKind LK) {
|
|
return (LK == LK_Shared) || (LKind == LK_Exclusive);
|
|
}
|
|
};
|
|
|
|
|
|
/// \brief A FactEntry stores a single fact that is known at a particular point
|
|
/// in the program execution. Currently, this is information regarding a lock
|
|
/// that is held at that point.
|
|
struct FactEntry {
|
|
SExpr MutID;
|
|
LockData LDat;
|
|
|
|
FactEntry(const SExpr& M, const LockData& L)
|
|
: MutID(M), LDat(L)
|
|
{ }
|
|
};
|
|
|
|
|
|
typedef unsigned short FactID;
|
|
|
|
/// \brief FactManager manages the memory for all facts that are created during
|
|
/// the analysis of a single routine.
|
|
class FactManager {
|
|
private:
|
|
std::vector<FactEntry> Facts;
|
|
|
|
public:
|
|
FactID newLock(const SExpr& M, const LockData& L) {
|
|
Facts.push_back(FactEntry(M,L));
|
|
return static_cast<unsigned short>(Facts.size() - 1);
|
|
}
|
|
|
|
const FactEntry& operator[](FactID F) const { return Facts[F]; }
|
|
FactEntry& operator[](FactID F) { return Facts[F]; }
|
|
};
|
|
|
|
|
|
/// \brief A FactSet is the set of facts that are known to be true at a
|
|
/// particular program point. FactSets must be small, because they are
|
|
/// frequently copied, and are thus implemented as a set of indices into a
|
|
/// table maintained by a FactManager. A typical FactSet only holds 1 or 2
|
|
/// locks, so we can get away with doing a linear search for lookup. Note
|
|
/// that a hashtable or map is inappropriate in this case, because lookups
|
|
/// may involve partial pattern matches, rather than exact matches.
|
|
class FactSet {
|
|
private:
|
|
typedef SmallVector<FactID, 4> FactVec;
|
|
|
|
FactVec FactIDs;
|
|
|
|
public:
|
|
typedef FactVec::iterator iterator;
|
|
typedef FactVec::const_iterator const_iterator;
|
|
|
|
iterator begin() { return FactIDs.begin(); }
|
|
const_iterator begin() const { return FactIDs.begin(); }
|
|
|
|
iterator end() { return FactIDs.end(); }
|
|
const_iterator end() const { return FactIDs.end(); }
|
|
|
|
bool isEmpty() const { return FactIDs.size() == 0; }
|
|
|
|
FactID addLock(FactManager& FM, const SExpr& M, const LockData& L) {
|
|
FactID F = FM.newLock(M, L);
|
|
FactIDs.push_back(F);
|
|
return F;
|
|
}
|
|
|
|
bool removeLock(FactManager& FM, const SExpr& M) {
|
|
unsigned n = FactIDs.size();
|
|
if (n == 0)
|
|
return false;
|
|
|
|
for (unsigned i = 0; i < n-1; ++i) {
|
|
if (FM[FactIDs[i]].MutID.matches(M)) {
|
|
FactIDs[i] = FactIDs[n-1];
|
|
FactIDs.pop_back();
|
|
return true;
|
|
}
|
|
}
|
|
if (FM[FactIDs[n-1]].MutID.matches(M)) {
|
|
FactIDs.pop_back();
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
LockData* findLock(FactManager &FM, const SExpr &M) const {
|
|
for (const_iterator I = begin(), E = end(); I != E; ++I) {
|
|
const SExpr &Exp = FM[*I].MutID;
|
|
if (Exp.matches(M))
|
|
return &FM[*I].LDat;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
LockData* findLockUniv(FactManager &FM, const SExpr &M) const {
|
|
for (const_iterator I = begin(), E = end(); I != E; ++I) {
|
|
const SExpr &Exp = FM[*I].MutID;
|
|
if (Exp.matches(M) || Exp.isUniversal())
|
|
return &FM[*I].LDat;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
FactEntry* findPartialMatch(FactManager &FM, const SExpr &M) const {
|
|
for (const_iterator I=begin(), E=end(); I != E; ++I) {
|
|
const SExpr& Exp = FM[*I].MutID;
|
|
if (Exp.partiallyMatches(M)) return &FM[*I];
|
|
}
|
|
return 0;
|
|
}
|
|
};
|
|
|
|
|
|
|
|
/// A Lockset maps each SExpr (defined above) to information about how it has
|
|
/// been locked.
|
|
typedef llvm::ImmutableMap<SExpr, 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 {
|
|
FactSet EntrySet; // Lockset held at entry to block
|
|
FactSet 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
|
|
bool Reachable; // Is this block reachable?
|
|
|
|
const FactSet &getSet(CFGBlockSide Side) const {
|
|
return Side == CBS_Entry ? EntrySet : ExitSet;
|
|
}
|
|
SourceLocation getLocation(CFGBlockSide Side) const {
|
|
return Side == CBS_Entry ? EntryLoc : ExitLoc;
|
|
}
|
|
|
|
private:
|
|
CFGBlockInfo(LocalVarContext EmptyCtx)
|
|
: EntryContext(EmptyCtx), ExitContext(EmptyCtx), Reachable(false)
|
|
{ }
|
|
|
|
public:
|
|
static CFGBlockInfo getEmptyBlockInfo(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 << " " << ((const 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(LocalVariableMap &M) {
|
|
return CFGBlockInfo(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 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;
|
|
LocalVariableMap LocalVarMap;
|
|
FactManager FactMan;
|
|
std::vector<CFGBlockInfo> BlockInfo;
|
|
|
|
public:
|
|
ThreadSafetyAnalyzer(ThreadSafetyHandler &H) : Handler(H) {}
|
|
|
|
void addLock(FactSet &FSet, const SExpr &Mutex, const LockData &LDat);
|
|
void removeLock(FactSet &FSet, const SExpr &Mutex,
|
|
SourceLocation UnlockLoc, bool FullyRemove=false);
|
|
|
|
template <typename AttrType>
|
|
void getMutexIDs(MutexIDList &Mtxs, AttrType *Attr, Expr *Exp,
|
|
const NamedDecl *D, VarDecl *SelfDecl=0);
|
|
|
|
template <class AttrType>
|
|
void getMutexIDs(MutexIDList &Mtxs, AttrType *Attr, Expr *Exp,
|
|
const NamedDecl *D,
|
|
const CFGBlock *PredBlock, const CFGBlock *CurrBlock,
|
|
Expr *BrE, bool Neg);
|
|
|
|
const CallExpr* getTrylockCallExpr(const Stmt *Cond, LocalVarContext C,
|
|
bool &Negate);
|
|
|
|
void getEdgeLockset(FactSet &Result, const FactSet &ExitSet,
|
|
const CFGBlock* PredBlock,
|
|
const CFGBlock *CurrBlock);
|
|
|
|
void intersectAndWarn(FactSet &FSet1, const FactSet &FSet2,
|
|
SourceLocation JoinLoc,
|
|
LockErrorKind LEK1, LockErrorKind LEK2,
|
|
bool Modify=true);
|
|
|
|
void intersectAndWarn(FactSet &FSet1, const FactSet &FSet2,
|
|
SourceLocation JoinLoc, LockErrorKind LEK1,
|
|
bool Modify=true) {
|
|
intersectAndWarn(FSet1, FSet2, JoinLoc, LEK1, LEK1, Modify);
|
|
}
|
|
|
|
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
|
|
void ThreadSafetyAnalyzer::addLock(FactSet &FSet, const SExpr &Mutex,
|
|
const LockData &LDat) {
|
|
// FIXME: deal with acquired before/after annotations.
|
|
// FIXME: Don't always warn when we have support for reentrant locks.
|
|
if (Mutex.shouldIgnore())
|
|
return;
|
|
|
|
if (FSet.findLock(FactMan, Mutex)) {
|
|
Handler.handleDoubleLock(Mutex.toString(), LDat.AcquireLoc);
|
|
} else {
|
|
FSet.addLock(FactMan, Mutex, LDat);
|
|
}
|
|
}
|
|
|
|
|
|
/// \brief Remove a lock from the lockset, warning if the lock is not there.
|
|
/// \param Mutex The lock expression corresponding to the lock to be removed
|
|
/// \param UnlockLoc The source location of the unlock (only used in error msg)
|
|
void ThreadSafetyAnalyzer::removeLock(FactSet &FSet,
|
|
const SExpr &Mutex,
|
|
SourceLocation UnlockLoc,
|
|
bool FullyRemove) {
|
|
if (Mutex.shouldIgnore())
|
|
return;
|
|
|
|
const LockData *LDat = FSet.findLock(FactMan, Mutex);
|
|
if (!LDat) {
|
|
Handler.handleUnmatchedUnlock(Mutex.toString(), UnlockLoc);
|
|
return;
|
|
}
|
|
|
|
if (LDat->UnderlyingMutex.isValid()) {
|
|
// This is scoped lockable object, which manages the real mutex.
|
|
if (FullyRemove) {
|
|
// We're destroying the managing object.
|
|
// Remove the underlying mutex if it exists; but don't warn.
|
|
if (FSet.findLock(FactMan, LDat->UnderlyingMutex))
|
|
FSet.removeLock(FactMan, LDat->UnderlyingMutex);
|
|
} else {
|
|
// We're releasing the underlying mutex, but not destroying the
|
|
// managing object. Warn on dual release.
|
|
if (!FSet.findLock(FactMan, LDat->UnderlyingMutex)) {
|
|
Handler.handleUnmatchedUnlock(LDat->UnderlyingMutex.toString(),
|
|
UnlockLoc);
|
|
}
|
|
FSet.removeLock(FactMan, LDat->UnderlyingMutex);
|
|
return;
|
|
}
|
|
}
|
|
FSet.removeLock(FactMan, Mutex);
|
|
}
|
|
|
|
|
|
/// \brief Extract the list of mutexIDs from the attribute on an expression,
|
|
/// and push them onto Mtxs, discarding any duplicates.
|
|
template <typename AttrType>
|
|
void ThreadSafetyAnalyzer::getMutexIDs(MutexIDList &Mtxs, AttrType *Attr,
|
|
Expr *Exp, const NamedDecl *D,
|
|
VarDecl *SelfDecl) {
|
|
typedef typename AttrType::args_iterator iterator_type;
|
|
|
|
if (Attr->args_size() == 0) {
|
|
// The mutex held is the "this" object.
|
|
SExpr Mu(0, Exp, D, SelfDecl);
|
|
if (!Mu.isValid())
|
|
SExpr::warnInvalidLock(Handler, 0, Exp, D);
|
|
else
|
|
Mtxs.push_back_nodup(Mu);
|
|
return;
|
|
}
|
|
|
|
for (iterator_type I=Attr->args_begin(), E=Attr->args_end(); I != E; ++I) {
|
|
SExpr Mu(*I, Exp, D, SelfDecl);
|
|
if (!Mu.isValid())
|
|
SExpr::warnInvalidLock(Handler, *I, Exp, D);
|
|
else
|
|
Mtxs.push_back_nodup(Mu);
|
|
}
|
|
}
|
|
|
|
|
|
/// \brief Extract the list of mutexIDs from a trylock attribute. If the
|
|
/// trylock applies to the given edge, then push them onto Mtxs, discarding
|
|
/// any duplicates.
|
|
template <class AttrType>
|
|
void ThreadSafetyAnalyzer::getMutexIDs(MutexIDList &Mtxs, AttrType *Attr,
|
|
Expr *Exp, const NamedDecl *D,
|
|
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) {
|
|
getMutexIDs(Mtxs, Attr, Exp, D);
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
bool getStaticBooleanValue(Expr* E, bool& TCond) {
|
|
if (isa<CXXNullPtrLiteralExpr>(E) || isa<GNUNullExpr>(E)) {
|
|
TCond = false;
|
|
return true;
|
|
} else if (CXXBoolLiteralExpr *BLE = dyn_cast<CXXBoolLiteralExpr>(E)) {
|
|
TCond = BLE->getValue();
|
|
return true;
|
|
} else if (IntegerLiteral *ILE = dyn_cast<IntegerLiteral>(E)) {
|
|
TCond = ILE->getValue().getBoolValue();
|
|
return true;
|
|
} else if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) {
|
|
return getStaticBooleanValue(CE->getSubExpr(), TCond);
|
|
}
|
|
return false;
|
|
}
|
|
|
|
|
|
// 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 ParenExpr *PE = dyn_cast<ParenExpr>(Cond)) {
|
|
return getTrylockCallExpr(PE->getSubExpr(), C, Negate);
|
|
}
|
|
else if (const ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(Cond)) {
|
|
return getTrylockCallExpr(CE->getSubExpr(), C, Negate);
|
|
}
|
|
else if (const ExprWithCleanups* EWC = dyn_cast<ExprWithCleanups>(Cond)) {
|
|
return getTrylockCallExpr(EWC->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);
|
|
}
|
|
return 0;
|
|
}
|
|
else if (const BinaryOperator *BOP = dyn_cast<BinaryOperator>(Cond)) {
|
|
if (BOP->getOpcode() == BO_EQ || BOP->getOpcode() == BO_NE) {
|
|
if (BOP->getOpcode() == BO_NE)
|
|
Negate = !Negate;
|
|
|
|
bool TCond = false;
|
|
if (getStaticBooleanValue(BOP->getRHS(), TCond)) {
|
|
if (!TCond) Negate = !Negate;
|
|
return getTrylockCallExpr(BOP->getLHS(), C, Negate);
|
|
}
|
|
else if (getStaticBooleanValue(BOP->getLHS(), TCond)) {
|
|
if (!TCond) Negate = !Negate;
|
|
return getTrylockCallExpr(BOP->getRHS(), C, Negate);
|
|
}
|
|
return 0;
|
|
}
|
|
return 0;
|
|
}
|
|
// FIXME -- handle && and || as well.
|
|
return 0;
|
|
}
|
|
|
|
|
|
/// \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.
|
|
void ThreadSafetyAnalyzer::getEdgeLockset(FactSet& Result,
|
|
const FactSet &ExitSet,
|
|
const CFGBlock *PredBlock,
|
|
const CFGBlock *CurrBlock) {
|
|
Result = ExitSet;
|
|
|
|
if (!PredBlock->getTerminatorCondition())
|
|
return;
|
|
|
|
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;
|
|
|
|
NamedDecl *FunDecl = dyn_cast_or_null<NamedDecl>(Exp->getCalleeDecl());
|
|
if(!FunDecl || !FunDecl->hasAttrs())
|
|
return;
|
|
|
|
|
|
MutexIDList ExclusiveLocksToAdd;
|
|
MutexIDList SharedLocksToAdd;
|
|
|
|
// 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);
|
|
getMutexIDs(ExclusiveLocksToAdd, A, Exp, FunDecl,
|
|
PredBlock, CurrBlock, A->getSuccessValue(), Negate);
|
|
break;
|
|
}
|
|
case attr::SharedTrylockFunction: {
|
|
SharedTrylockFunctionAttr *A =
|
|
cast<SharedTrylockFunctionAttr>(Attr);
|
|
getMutexIDs(SharedLocksToAdd, A, Exp, FunDecl,
|
|
PredBlock, CurrBlock, A->getSuccessValue(), Negate);
|
|
break;
|
|
}
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
|
|
// Add and remove locks.
|
|
SourceLocation Loc = Exp->getExprLoc();
|
|
for (unsigned i=0,n=ExclusiveLocksToAdd.size(); i<n; ++i) {
|
|
addLock(Result, ExclusiveLocksToAdd[i],
|
|
LockData(Loc, LK_Exclusive));
|
|
}
|
|
for (unsigned i=0,n=SharedLocksToAdd.size(); i<n; ++i) {
|
|
addLock(Result, SharedLocksToAdd[i],
|
|
LockData(Loc, LK_Shared));
|
|
}
|
|
}
|
|
|
|
|
|
/// \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;
|
|
FactSet FSet;
|
|
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 warnIfMutexHeld(const NamedDecl *D, Expr *Exp, Expr *MutexExp);
|
|
|
|
void checkAccess(Expr *Exp, AccessKind AK);
|
|
void checkDereference(Expr *Exp, AccessKind AK);
|
|
void handleCall(Expr *Exp, const NamedDecl *D, VarDecl *VD = 0);
|
|
|
|
public:
|
|
BuildLockset(ThreadSafetyAnalyzer *Anlzr, CFGBlockInfo &Info)
|
|
: StmtVisitor<BuildLockset>(),
|
|
Analyzer(Anlzr),
|
|
FSet(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);
|
|
|
|
SExpr Mutex(MutexExp, Exp, D);
|
|
if (!Mutex.isValid()) {
|
|
SExpr::warnInvalidLock(Analyzer->Handler, MutexExp, Exp, D);
|
|
return;
|
|
} else if (Mutex.shouldIgnore()) {
|
|
return;
|
|
}
|
|
|
|
LockData* LDat = FSet.findLockUniv(Analyzer->FactMan, Mutex);
|
|
bool NoError = true;
|
|
if (!LDat) {
|
|
// No exact match found. Look for a partial match.
|
|
FactEntry* FEntry = FSet.findPartialMatch(Analyzer->FactMan, Mutex);
|
|
if (FEntry) {
|
|
// Warn that there's no precise match.
|
|
LDat = &FEntry->LDat;
|
|
std::string PartMatchStr = FEntry->MutID.toString();
|
|
StringRef PartMatchName(PartMatchStr);
|
|
Analyzer->Handler.handleMutexNotHeld(D, POK, Mutex.toString(), LK,
|
|
Exp->getExprLoc(), &PartMatchName);
|
|
} else {
|
|
// Warn that there's no match at all.
|
|
Analyzer->Handler.handleMutexNotHeld(D, POK, Mutex.toString(), LK,
|
|
Exp->getExprLoc());
|
|
}
|
|
NoError = false;
|
|
}
|
|
// Make sure the mutex we found is the right kind.
|
|
if (NoError && LDat && !LDat->isAtLeast(LK))
|
|
Analyzer->Handler.handleMutexNotHeld(D, POK, Mutex.toString(), LK,
|
|
Exp->getExprLoc());
|
|
}
|
|
|
|
/// \brief Warn if the LSet contains the given lock.
|
|
void BuildLockset::warnIfMutexHeld(const NamedDecl *D, Expr* Exp,
|
|
Expr *MutexExp) {
|
|
SExpr Mutex(MutexExp, Exp, D);
|
|
if (!Mutex.isValid()) {
|
|
SExpr::warnInvalidLock(Analyzer->Handler, MutexExp, Exp, D);
|
|
return;
|
|
}
|
|
|
|
LockData* LDat = FSet.findLock(Analyzer->FactMan, Mutex);
|
|
if (LDat) {
|
|
std::string DeclName = D->getNameAsString();
|
|
StringRef DeclNameSR (DeclName);
|
|
Analyzer->Handler.handleFunExcludesLock(DeclNameSR, Mutex.toString(),
|
|
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>() && FSet.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>() && FSet.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.
|
|
///
|
|
void BuildLockset::handleCall(Expr *Exp, const NamedDecl *D, VarDecl *VD) {
|
|
const AttrVec &ArgAttrs = D->getAttrs();
|
|
MutexIDList ExclusiveLocksToAdd;
|
|
MutexIDList SharedLocksToAdd;
|
|
MutexIDList LocksToRemove;
|
|
|
|
for(unsigned i = 0; i < ArgAttrs.size(); ++i) {
|
|
Attr *At = const_cast<Attr*>(ArgAttrs[i]);
|
|
switch (At->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>(At);
|
|
Analyzer->getMutexIDs(ExclusiveLocksToAdd, 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>(At);
|
|
Analyzer->getMutexIDs(SharedLocksToAdd, 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 *A = cast<UnlockFunctionAttr>(At);
|
|
Analyzer->getMutexIDs(LocksToRemove, A, Exp, D, VD);
|
|
break;
|
|
}
|
|
|
|
case attr::ExclusiveLocksRequired: {
|
|
ExclusiveLocksRequiredAttr *A = cast<ExclusiveLocksRequiredAttr>(At);
|
|
|
|
for (ExclusiveLocksRequiredAttr::args_iterator
|
|
I = A->args_begin(), E = A->args_end(); I != E; ++I)
|
|
warnIfMutexNotHeld(D, Exp, AK_Written, *I, POK_FunctionCall);
|
|
break;
|
|
}
|
|
|
|
case attr::SharedLocksRequired: {
|
|
SharedLocksRequiredAttr *A = cast<SharedLocksRequiredAttr>(At);
|
|
|
|
for (SharedLocksRequiredAttr::args_iterator I = A->args_begin(),
|
|
E = A->args_end(); I != E; ++I)
|
|
warnIfMutexNotHeld(D, Exp, AK_Read, *I, POK_FunctionCall);
|
|
break;
|
|
}
|
|
|
|
case attr::LocksExcluded: {
|
|
LocksExcludedAttr *A = cast<LocksExcludedAttr>(At);
|
|
|
|
for (LocksExcludedAttr::args_iterator I = A->args_begin(),
|
|
E = A->args_end(); I != E; ++I) {
|
|
warnIfMutexHeld(D, Exp, *I);
|
|
}
|
|
break;
|
|
}
|
|
|
|
// Ignore other (non thread-safety) attributes
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
|
|
// Figure out if we're calling the constructor of scoped lockable class
|
|
bool isScopedVar = false;
|
|
if (VD) {
|
|
if (const CXXConstructorDecl *CD = dyn_cast<const CXXConstructorDecl>(D)) {
|
|
const CXXRecordDecl* PD = CD->getParent();
|
|
if (PD && PD->getAttr<ScopedLockableAttr>())
|
|
isScopedVar = true;
|
|
}
|
|
}
|
|
|
|
// Add locks.
|
|
SourceLocation Loc = Exp->getExprLoc();
|
|
for (unsigned i=0,n=ExclusiveLocksToAdd.size(); i<n; ++i) {
|
|
Analyzer->addLock(FSet, ExclusiveLocksToAdd[i],
|
|
LockData(Loc, LK_Exclusive, isScopedVar));
|
|
}
|
|
for (unsigned i=0,n=SharedLocksToAdd.size(); i<n; ++i) {
|
|
Analyzer->addLock(FSet, SharedLocksToAdd[i],
|
|
LockData(Loc, LK_Shared, isScopedVar));
|
|
}
|
|
|
|
// Add the managing object as a dummy mutex, mapped to the underlying mutex.
|
|
// FIXME -- this doesn't work if we acquire multiple locks.
|
|
if (isScopedVar) {
|
|
SourceLocation MLoc = VD->getLocation();
|
|
DeclRefExpr DRE(VD, false, VD->getType(), VK_LValue, VD->getLocation());
|
|
SExpr SMutex(&DRE, 0, 0);
|
|
|
|
for (unsigned i=0,n=ExclusiveLocksToAdd.size(); i<n; ++i) {
|
|
Analyzer->addLock(FSet, SMutex, LockData(MLoc, LK_Exclusive,
|
|
ExclusiveLocksToAdd[i]));
|
|
}
|
|
for (unsigned i=0,n=SharedLocksToAdd.size(); i<n; ++i) {
|
|
Analyzer->addLock(FSet, SMutex, LockData(MLoc, LK_Shared,
|
|
SharedLocksToAdd[i]));
|
|
}
|
|
}
|
|
|
|
// Remove locks.
|
|
// FIXME -- should only fully remove if the attribute refers to 'this'.
|
|
bool Dtor = isa<CXXDestructorDecl>(D);
|
|
for (unsigned i=0,n=LocksToRemove.size(); i<n; ++i) {
|
|
Analyzer->removeLock(FSet, LocksToRemove[i], Loc, Dtor);
|
|
}
|
|
}
|
|
|
|
|
|
/// \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();
|
|
// handle constructors that involve temporaries
|
|
if (ExprWithCleanups *EWC = dyn_cast_or_null<ExprWithCleanups>(E))
|
|
E = EWC->getSubExpr();
|
|
|
|
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 FSet1 The first lockset.
|
|
/// \param FSet2 The second lockset.
|
|
/// \param JoinLoc The location of the join point for error reporting
|
|
/// \param LEK1 The error message to report if a mutex is missing from LSet1
|
|
/// \param LEK2 The error message to report if a mutex is missing from Lset2
|
|
void ThreadSafetyAnalyzer::intersectAndWarn(FactSet &FSet1,
|
|
const FactSet &FSet2,
|
|
SourceLocation JoinLoc,
|
|
LockErrorKind LEK1,
|
|
LockErrorKind LEK2,
|
|
bool Modify) {
|
|
FactSet FSet1Orig = FSet1;
|
|
|
|
for (FactSet::const_iterator I = FSet2.begin(), E = FSet2.end();
|
|
I != E; ++I) {
|
|
const SExpr &FSet2Mutex = FactMan[*I].MutID;
|
|
const LockData &LDat2 = FactMan[*I].LDat;
|
|
|
|
if (const LockData *LDat1 = FSet1.findLock(FactMan, FSet2Mutex)) {
|
|
if (LDat1->LKind != LDat2.LKind) {
|
|
Handler.handleExclusiveAndShared(FSet2Mutex.toString(),
|
|
LDat2.AcquireLoc,
|
|
LDat1->AcquireLoc);
|
|
if (Modify && LDat1->LKind != LK_Exclusive) {
|
|
FSet1.removeLock(FactMan, FSet2Mutex);
|
|
FSet1.addLock(FactMan, FSet2Mutex, LDat2);
|
|
}
|
|
}
|
|
} else {
|
|
if (LDat2.UnderlyingMutex.isValid()) {
|
|
if (FSet2.findLock(FactMan, LDat2.UnderlyingMutex)) {
|
|
// If this is a scoped lock that manages another mutex, and if the
|
|
// underlying mutex is still held, then warn about the underlying
|
|
// mutex.
|
|
Handler.handleMutexHeldEndOfScope(LDat2.UnderlyingMutex.toString(),
|
|
LDat2.AcquireLoc,
|
|
JoinLoc, LEK1);
|
|
}
|
|
}
|
|
else if (!LDat2.Managed && !FSet2Mutex.isUniversal())
|
|
Handler.handleMutexHeldEndOfScope(FSet2Mutex.toString(),
|
|
LDat2.AcquireLoc,
|
|
JoinLoc, LEK1);
|
|
}
|
|
}
|
|
|
|
for (FactSet::const_iterator I = FSet1.begin(), E = FSet1.end();
|
|
I != E; ++I) {
|
|
const SExpr &FSet1Mutex = FactMan[*I].MutID;
|
|
const LockData &LDat1 = FactMan[*I].LDat;
|
|
|
|
if (!FSet2.findLock(FactMan, FSet1Mutex)) {
|
|
if (LDat1.UnderlyingMutex.isValid()) {
|
|
if (FSet1Orig.findLock(FactMan, LDat1.UnderlyingMutex)) {
|
|
// If this is a scoped lock that manages another mutex, and if the
|
|
// underlying mutex is still held, then warn about the underlying
|
|
// mutex.
|
|
Handler.handleMutexHeldEndOfScope(LDat1.UnderlyingMutex.toString(),
|
|
LDat1.AcquireLoc,
|
|
JoinLoc, LEK1);
|
|
}
|
|
}
|
|
else if (!LDat1.Managed && !FSet1Mutex.isUniversal())
|
|
Handler.handleMutexHeldEndOfScope(FSet1Mutex.toString(),
|
|
LDat1.AcquireLoc,
|
|
JoinLoc, LEK2);
|
|
if (Modify)
|
|
FSet1.removeLock(FactMan, FSet1Mutex);
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
|
|
/// \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(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);
|
|
|
|
// Mark entry block as reachable
|
|
BlockInfo[CFGraph->getEntry().getBlockID()].Reachable = true;
|
|
|
|
// 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();
|
|
FactSet &InitialLockset = BlockInfo[FirstBlock->getBlockID()].EntrySet;
|
|
const AttrVec &ArgAttrs = D->getAttrs();
|
|
|
|
MutexIDList ExclusiveLocksToAdd;
|
|
MutexIDList SharedLocksToAdd;
|
|
|
|
SourceLocation Loc = D->getLocation();
|
|
for (unsigned i = 0; i < ArgAttrs.size(); ++i) {
|
|
Attr *Attr = ArgAttrs[i];
|
|
Loc = Attr->getLocation();
|
|
if (ExclusiveLocksRequiredAttr *A
|
|
= dyn_cast<ExclusiveLocksRequiredAttr>(Attr)) {
|
|
getMutexIDs(ExclusiveLocksToAdd, A, (Expr*) 0, D);
|
|
} else if (SharedLocksRequiredAttr *A
|
|
= dyn_cast<SharedLocksRequiredAttr>(Attr)) {
|
|
getMutexIDs(SharedLocksToAdd, A, (Expr*) 0, D);
|
|
} 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;
|
|
}
|
|
}
|
|
|
|
// FIXME -- Loc can be wrong here.
|
|
for (unsigned i=0,n=ExclusiveLocksToAdd.size(); i<n; ++i) {
|
|
addLock(InitialLockset, ExclusiveLocksToAdd[i],
|
|
LockData(Loc, LK_Exclusive));
|
|
}
|
|
for (unsigned i=0,n=SharedLocksToAdd.size(); i<n; ++i) {
|
|
addLock(InitialLockset, SharedLocksToAdd[i],
|
|
LockData(Loc, LK_Shared));
|
|
}
|
|
}
|
|
|
|
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;
|
|
|
|
int PrevBlockID = (*PI)->getBlockID();
|
|
CFGBlockInfo *PrevBlockInfo = &BlockInfo[PrevBlockID];
|
|
|
|
// Ignore edges from blocks that can't return.
|
|
if ((*PI)->hasNoReturnElement() || !PrevBlockInfo->Reachable)
|
|
continue;
|
|
|
|
// Okay, we can reach this block from the entry.
|
|
CurrBlockInfo->Reachable = true;
|
|
|
|
// 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;
|
|
}
|
|
}
|
|
|
|
|
|
FactSet PrevLockset;
|
|
getEdgeLockset(PrevLockset, PrevBlockInfo->ExitSet, *PI, CurrBlock);
|
|
|
|
if (!LocksetInitialized) {
|
|
CurrBlockInfo->EntrySet = PrevLockset;
|
|
LocksetInitialized = true;
|
|
} else {
|
|
intersectAndWarn(CurrBlockInfo->EntrySet, PrevLockset,
|
|
CurrBlockInfo->EntryLoc,
|
|
LEK_LockedSomePredecessors);
|
|
}
|
|
}
|
|
|
|
// Skip rest of block if it's not reachable.
|
|
if (!CurrBlockInfo->Reachable)
|
|
continue;
|
|
|
|
// 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);
|
|
|
|
FactSet PrevLockset;
|
|
getEdgeLockset(PrevLockset, PrevBlockInfo->ExitSet,
|
|
PrevBlock, CurrBlock);
|
|
|
|
// Do not update EntrySet.
|
|
intersectAndWarn(CurrBlockInfo->EntrySet, PrevLockset,
|
|
PrevBlockInfo->ExitLoc,
|
|
IsLoop ? LEK_LockedSomeLoopIterations
|
|
: LEK_LockedSomePredecessors,
|
|
false);
|
|
}
|
|
}
|
|
|
|
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.FSet;
|
|
|
|
// 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,
|
|
false);
|
|
}
|
|
}
|
|
|
|
CFGBlockInfo *Initial = &BlockInfo[CFGraph->getEntry().getBlockID()];
|
|
CFGBlockInfo *Final = &BlockInfo[CFGraph->getExit().getBlockID()];
|
|
|
|
// Skip the final check if the exit block is unreachable.
|
|
if (!Final->Reachable)
|
|
return;
|
|
|
|
// FIXME: Should we call this function for all blocks which exit the function?
|
|
intersectAndWarn(Initial->EntrySet, Final->ExitSet,
|
|
Final->ExitLoc,
|
|
LEK_LockedAtEndOfFunction,
|
|
LEK_NotLockedAtEndOfFunction,
|
|
false);
|
|
}
|
|
|
|
} // 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
|