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//===- ThreadSafetyCommon.h ------------------------------------*- C++ --*-===//
// The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
// Parts of thread safety analysis that are not specific to thread safety
// itself have been factored into classes here, where they can be potentially
// used by other analyses. Currently these include:
// * Generalize clang CFG visitors.
// * Conversion of the clang CFG to SSA form.
// * Translation of clang Exprs to TIL SExprs
#include "clang/Analysis/Analyses/PostOrderCFGView.h"
#include "clang/Analysis/Analyses/ThreadSafetyTIL.h"
#include "clang/Analysis/AnalysisContext.h"
#include "clang/Basic/OperatorKinds.h"
#include <memory>
#include <vector>
namespace clang {
namespace threadSafety {
// This class defines the interface of a clang CFG Visitor.
// CFGWalker will invoke the following methods.
// Note that methods are not virtual; the visitor is templatized.
class CFGVisitor {
// Enter the CFG for Decl D, and perform any initial setup operations.
void enterCFG(CFG *Cfg, const NamedDecl *D, const CFGBlock *First) {}
// Enter a CFGBlock.
void enterCFGBlock(const CFGBlock *B) {}
// Returns true if this visitor implements handlePredecessor
bool visitPredecessors() { return true; }
// Process a predecessor edge.
void handlePredecessor(const CFGBlock *Pred) {}
// Process a successor back edge to a previously visited block.
void handlePredecessorBackEdge(const CFGBlock *Pred) {}
// Called just before processing statements.
void enterCFGBlockBody(const CFGBlock *B) {}
// Process an ordinary statement.
void handleStatement(const Stmt *S) {}
// Process a destructor call
void handleDestructorCall(const VarDecl *VD, const CXXDestructorDecl *DD) {}
// Called after all statements have been handled.
void exitCFGBlockBody(const CFGBlock *B) {}
// Return true
bool visitSuccessors() { return true; }
// Process a successor edge.
void handleSuccessor(const CFGBlock *Succ) {}
// Process a successor back edge to a previously visited block.
void handleSuccessorBackEdge(const CFGBlock *Succ) {}
// Leave a CFGBlock.
void exitCFGBlock(const CFGBlock *B) {}
// Leave the CFG, and perform any final cleanup operations.
void exitCFG(const CFGBlock *Last) {}
// Walks the clang CFG, and invokes methods on a given CFGVisitor.
class CFGWalker {
CFGWalker() : CFGraph(nullptr), ACtx(nullptr), SortedGraph(nullptr) {}
// Initialize the CFGWalker. This setup only needs to be done once, even
// if there are multiple passes over the CFG.
bool init(AnalysisDeclContext &AC) {
ACtx = &AC;
CFGraph = AC.getCFG();
if (!CFGraph)
return false;
// Ignore anonymous functions.
if (!dyn_cast_or_null<NamedDecl>(AC.getDecl()))
return false;
SortedGraph = AC.getAnalysis<PostOrderCFGView>();
if (!SortedGraph)
return false;
return true;
// Traverse the CFG, calling methods on V as appropriate.
template <class Visitor>
void walk(Visitor &V) {
PostOrderCFGView::CFGBlockSet VisitedBlocks(CFGraph);
V.enterCFG(CFGraph, getDecl(), &CFGraph->getEntry());
for (const auto *CurrBlock : *SortedGraph) {
// Process predecessors, handling back edges last
if (V.visitPredecessors()) {
SmallVector<CFGBlock*, 4> BackEdges;
// Process successors
for (CFGBlock::const_pred_iterator SI = CurrBlock->pred_begin(),
SE = CurrBlock->pred_end();
SI != SE; ++SI) {
if (*SI == nullptr)
if (!VisitedBlocks.alreadySet(*SI)) {
for (auto *Blk : BackEdges)
// Process statements
for (const auto &BI : *CurrBlock) {
switch (BI.getKind()) {
case CFGElement::Statement: {
case CFGElement::AutomaticObjectDtor: {
CFGAutomaticObjDtor AD = BI.castAs<CFGAutomaticObjDtor>();
CXXDestructorDecl *DD = const_cast<CXXDestructorDecl*>(
VarDecl *VD = const_cast<VarDecl*>(AD.getVarDecl());
V.handleDestructorCall(VD, DD);
// Process successors, handling back edges first.
if (V.visitSuccessors()) {
SmallVector<CFGBlock*, 8> ForwardEdges;
// Process successors
for (CFGBlock::const_succ_iterator SI = CurrBlock->succ_begin(),
SE = CurrBlock->succ_end();
SI != SE; ++SI) {
if (*SI == nullptr)
if (!VisitedBlocks.alreadySet(*SI)) {
for (auto *Blk : ForwardEdges)
const CFG *getGraph() const { return CFGraph; }
CFG *getGraph() { return CFGraph; }
const FunctionDecl *getDecl() const {
return dyn_cast<FunctionDecl>(ACtx->getDecl());
const PostOrderCFGView *getSortedGraph() const { return SortedGraph; }
CFG *CFGraph;
AnalysisDeclContext *ACtx;
PostOrderCFGView *SortedGraph;
// Translate clang::Expr to til::SExpr.
class SExprBuilder {
/// \brief Encapsulates the lexical context of a function call. The lexical
/// context includes the arguments to the call, including the implicit object
/// argument. When an attribute containing a mutex expression is attached to
/// a method, the expression may refer to formal parameters of the method.
/// Actual arguments must be substituted for formal parameters to derive
/// the appropriate mutex expression in the lexical context where the function
/// is called. PrevCtx holds the context in which the arguments themselves
/// should be evaluated; multiple calling contexts can be chained together
/// by the lock_returned attribute.
struct CallingContext {
const NamedDecl *AttrDecl; // The decl to which the attr is attached.
const Expr *SelfArg; // Implicit object argument -- e.g. 'this'
unsigned NumArgs; // Number of funArgs
const Expr *const *FunArgs; // Function arguments
CallingContext *Prev; // The previous context; or 0 if none.
bool SelfArrow; // is Self referred to with -> or .?
CallingContext(const NamedDecl *D = nullptr, const Expr *S = nullptr,
unsigned N = 0, const Expr *const *A = nullptr,
CallingContext *P = nullptr)
: AttrDecl(D), SelfArg(S), NumArgs(N), FunArgs(A), Prev(P),
SExprBuilder(til::MemRegionRef A)
: Arena(A), SelfVar(nullptr), Scfg(nullptr), CurrentBB(nullptr),
CurrentBlockInfo(nullptr) {
// FIXME: we don't always have a self-variable.
SelfVar = new (Arena) til::Variable(til::Variable::VK_SFun);
// Translate a clang statement or expression to a TIL expression.
// Also performs substitution of variables; Ctx provides the context.
// Dispatches on the type of S.
til::SExpr *translate(const Stmt *S, CallingContext *Ctx);
til::SCFG *buildCFG(CFGWalker &Walker);
til::SExpr *lookupStmt(const Stmt *S);
til::BasicBlock *lookupBlock(const CFGBlock *B) {
return BlockMap[B->getBlockID()];
const til::SCFG *getCFG() const { return Scfg; }
til::SCFG *getCFG() { return Scfg; }
til::SExpr *translateDeclRefExpr(const DeclRefExpr *DRE,
CallingContext *Ctx) ;
til::SExpr *translateCXXThisExpr(const CXXThisExpr *TE, CallingContext *Ctx);
til::SExpr *translateMemberExpr(const MemberExpr *ME, CallingContext *Ctx);
til::SExpr *translateCallExpr(const CallExpr *CE, CallingContext *Ctx);
til::SExpr *translateCXXMemberCallExpr(const CXXMemberCallExpr *ME,
CallingContext *Ctx);
til::SExpr *translateCXXOperatorCallExpr(const CXXOperatorCallExpr *OCE,
CallingContext *Ctx);
til::SExpr *translateUnaryOperator(const UnaryOperator *UO,
CallingContext *Ctx);
til::SExpr *translateBinAssign(til::TIL_BinaryOpcode Op,
const BinaryOperator *BO,
CallingContext *Ctx);
til::SExpr *translateBinaryOperator(const BinaryOperator *BO,
CallingContext *Ctx);
til::SExpr *translateCastExpr(const CastExpr *CE, CallingContext *Ctx);
til::SExpr *translateArraySubscriptExpr(const ArraySubscriptExpr *E,
CallingContext *Ctx);
til::SExpr *translateConditionalOperator(const ConditionalOperator *C,
CallingContext *Ctx);
til::SExpr *translateBinaryConditionalOperator(
const BinaryConditionalOperator *C, CallingContext *Ctx);
til::SExpr *translateDeclStmt(const DeclStmt *S, CallingContext *Ctx);
// Map from statements in the clang CFG to SExprs in the til::SCFG.
typedef llvm::DenseMap<const Stmt*, til::SExpr*> StatementMap;
// Map from clang local variables to indices in a LVarDefinitionMap.
typedef llvm::DenseMap<const ValueDecl *, unsigned> LVarIndexMap;
// Map from local variable indices to SSA variables (or constants).
typedef std::pair<const ValueDecl *, til::SExpr *> NameVarPair;
typedef CopyOnWriteVector<NameVarPair> LVarDefinitionMap;
struct BlockInfo {
LVarDefinitionMap ExitMap;
bool HasBackEdges;
unsigned UnprocessedSuccessors; // Successors yet to be processed
unsigned ProcessedPredecessors; // Predecessors already processed
: HasBackEdges(false), UnprocessedSuccessors(0),
ProcessedPredecessors(0) {}
BlockInfo(BlockInfo &&RHS)
: ExitMap(std::move(RHS.ExitMap)),
ProcessedPredecessors(RHS.ProcessedPredecessors) {}
BlockInfo &operator=(BlockInfo &&RHS) {
if (this != &RHS) {
ExitMap = std::move(RHS.ExitMap);
HasBackEdges = RHS.HasBackEdges;
UnprocessedSuccessors = RHS.UnprocessedSuccessors;
ProcessedPredecessors = RHS.ProcessedPredecessors;
return *this;
BlockInfo(const BlockInfo &) LLVM_DELETED_FUNCTION;
void operator=(const BlockInfo &) LLVM_DELETED_FUNCTION;
// We implement the CFGVisitor API
friend class CFGWalker;
void enterCFG(CFG *Cfg, const FunctionDecl *D, const CFGBlock *First);
void enterCFGBlock(const CFGBlock *B);
bool visitPredecessors() { return true; }
void handlePredecessor(const CFGBlock *Pred);
void handlePredecessorBackEdge(const CFGBlock *Pred);
void enterCFGBlockBody(const CFGBlock *B);
void handleStatement(const Stmt *S);
void handleDestructorCall(const VarDecl *VD, const CXXDestructorDecl *DD);
void exitCFGBlockBody(const CFGBlock *B);
bool visitSuccessors() { return true; }
void handleSuccessor(const CFGBlock *Succ);
void handleSuccessorBackEdge(const CFGBlock *Succ);
void exitCFGBlock(const CFGBlock *B);
void exitCFG(const CFGBlock *Last);
void insertStmt(const Stmt *S, til::SExpr *E) {
SMap.insert(std::make_pair(S, E));
til::SExpr *getCurrentLVarDefinition(const ValueDecl *VD);
til::SExpr *addStatement(til::SExpr *E, const Stmt *S, const ValueDecl *VD=0);
til::SExpr *lookupVarDecl(const ValueDecl *VD);
til::SExpr *addVarDecl(const ValueDecl *VD, til::SExpr *E);
til::SExpr *updateVarDecl(const ValueDecl *VD, til::SExpr *E);
void makePhiNodeVar(unsigned i, unsigned NPreds, til::SExpr *E);
void mergeEntryMap(LVarDefinitionMap Map);
void mergeEntryMapBackEdge();
void mergePhiNodesBackEdge(const CFGBlock *Blk);
til::MemRegionRef Arena;
til::Variable *SelfVar; // Variable to use for 'this'. May be null.
til::SCFG *Scfg;
StatementMap SMap; // Map from Stmt to TIL Variables
LVarIndexMap LVarIdxMap; // Indices of clang local vars.
std::vector<til::BasicBlock *> BlockMap; // Map from clang to til BBs.
std::vector<BlockInfo> BBInfo; // Extra information per BB.
// Indexed by clang BlockID.
std::unique_ptr<SExprBuilder::CallingContext> CallCtx; // Root calling context
LVarDefinitionMap CurrentLVarMap;
std::vector<til::Variable*> CurrentArguments;
std::vector<til::Variable*> CurrentInstructions;
std::vector<til::Variable*> IncompleteArgs;
til::BasicBlock *CurrentBB;
BlockInfo *CurrentBlockInfo;
// Dump an SCFG to llvm::errs().
void printSCFG(CFGWalker &Walker);
} // end namespace threadSafety
} // end namespace clang