1 //===- ThreadSafetyCommon.h -------------------------------------*- C++ -*-===//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
9 // Parts of thread safety analysis that are not specific to thread safety
10 // itself have been factored into classes here, where they can be potentially
11 // used by other analyses. Currently these include:
13 // * Generalize clang CFG visitors.
14 // * Conversion of the clang CFG to SSA form.
15 // * Translation of clang Exprs to TIL SExprs
17 // UNDER CONSTRUCTION. USE AT YOUR OWN RISK.
19 //===----------------------------------------------------------------------===//
21 #ifndef LLVM_CLANG_ANALYSIS_ANALYSES_THREADSAFETYCOMMON_H
22 #define LLVM_CLANG_ANALYSIS_ANALYSES_THREADSAFETYCOMMON_H
24 #include "clang/AST/Decl.h"
25 #include "clang/Analysis/Analyses/PostOrderCFGView.h"
26 #include "clang/Analysis/Analyses/ThreadSafetyTIL.h"
27 #include "clang/Analysis/Analyses/ThreadSafetyTraverse.h"
28 #include "clang/Analysis/Analyses/ThreadSafetyUtil.h"
29 #include "clang/Analysis/AnalysisDeclContext.h"
30 #include "clang/Analysis/CFG.h"
31 #include "clang/Basic/LLVM.h"
32 #include "llvm/ADT/DenseMap.h"
33 #include "llvm/ADT/SmallVector.h"
34 #include "llvm/Support/Casting.h"
42 class AbstractConditionalOperator;
43 class ArraySubscriptExpr;
47 class CXXDestructorDecl;
48 class CXXMemberCallExpr;
49 class CXXOperatorCallExpr;
58 namespace threadSafety {
60 // Various helper functions on til::SExpr
63 inline bool equals(const til::SExpr *E1, const til::SExpr *E2) {
64 return til::EqualsComparator::compareExprs(E1, E2);
67 inline bool matches(const til::SExpr *E1, const til::SExpr *E2) {
68 // We treat a top-level wildcard as the "univsersal" lock.
69 // It matches everything for the purpose of checking locks, but not
70 // for unlocking them.
71 if (isa<til::Wildcard>(E1))
72 return isa<til::Wildcard>(E2);
73 if (isa<til::Wildcard>(E2))
74 return isa<til::Wildcard>(E1);
76 return til::MatchComparator::compareExprs(E1, E2);
79 inline bool partiallyMatches(const til::SExpr *E1, const til::SExpr *E2) {
80 const auto *PE1 = dyn_cast_or_null<til::Project>(E1);
83 const auto *PE2 = dyn_cast_or_null<til::Project>(E2);
86 return PE1->clangDecl() == PE2->clangDecl();
89 inline std::string toString(const til::SExpr *E) {
91 til::StdPrinter::print(E, ss);
97 // This class defines the interface of a clang CFG Visitor.
98 // CFGWalker will invoke the following methods.
99 // Note that methods are not virtual; the visitor is templatized.
101 // Enter the CFG for Decl D, and perform any initial setup operations.
102 void enterCFG(CFG *Cfg, const NamedDecl *D, const CFGBlock *First) {}
105 void enterCFGBlock(const CFGBlock *B) {}
107 // Returns true if this visitor implements handlePredecessor
108 bool visitPredecessors() { return true; }
110 // Process a predecessor edge.
111 void handlePredecessor(const CFGBlock *Pred) {}
113 // Process a successor back edge to a previously visited block.
114 void handlePredecessorBackEdge(const CFGBlock *Pred) {}
116 // Called just before processing statements.
117 void enterCFGBlockBody(const CFGBlock *B) {}
119 // Process an ordinary statement.
120 void handleStatement(const Stmt *S) {}
122 // Process a destructor call
123 void handleDestructorCall(const VarDecl *VD, const CXXDestructorDecl *DD) {}
125 // Called after all statements have been handled.
126 void exitCFGBlockBody(const CFGBlock *B) {}
129 bool visitSuccessors() { return true; }
131 // Process a successor edge.
132 void handleSuccessor(const CFGBlock *Succ) {}
134 // Process a successor back edge to a previously visited block.
135 void handleSuccessorBackEdge(const CFGBlock *Succ) {}
138 void exitCFGBlock(const CFGBlock *B) {}
140 // Leave the CFG, and perform any final cleanup operations.
141 void exitCFG(const CFGBlock *Last) {}
144 // Walks the clang CFG, and invokes methods on a given CFGVisitor.
147 CFGWalker() = default;
149 // Initialize the CFGWalker. This setup only needs to be done once, even
150 // if there are multiple passes over the CFG.
151 bool init(AnalysisDeclContext &AC) {
153 CFGraph = AC.getCFG();
157 // Ignore anonymous functions.
158 if (!dyn_cast_or_null<NamedDecl>(AC.getDecl()))
161 SortedGraph = AC.getAnalysis<PostOrderCFGView>();
168 // Traverse the CFG, calling methods on V as appropriate.
169 template <class Visitor>
170 void walk(Visitor &V) {
171 PostOrderCFGView::CFGBlockSet VisitedBlocks(CFGraph);
173 V.enterCFG(CFGraph, getDecl(), &CFGraph->getEntry());
175 for (const auto *CurrBlock : *SortedGraph) {
176 VisitedBlocks.insert(CurrBlock);
178 V.enterCFGBlock(CurrBlock);
180 // Process predecessors, handling back edges last
181 if (V.visitPredecessors()) {
182 SmallVector<CFGBlock*, 4> BackEdges;
183 // Process successors
184 for (CFGBlock::const_pred_iterator SI = CurrBlock->pred_begin(),
185 SE = CurrBlock->pred_end();
190 if (!VisitedBlocks.alreadySet(*SI)) {
191 BackEdges.push_back(*SI);
194 V.handlePredecessor(*SI);
197 for (auto *Blk : BackEdges)
198 V.handlePredecessorBackEdge(Blk);
201 V.enterCFGBlockBody(CurrBlock);
203 // Process statements
204 for (const auto &BI : *CurrBlock) {
205 switch (BI.getKind()) {
206 case CFGElement::Statement:
207 V.handleStatement(BI.castAs<CFGStmt>().getStmt());
210 case CFGElement::AutomaticObjectDtor: {
211 CFGAutomaticObjDtor AD = BI.castAs<CFGAutomaticObjDtor>();
212 auto *DD = const_cast<CXXDestructorDecl *>(
213 AD.getDestructorDecl(ACtx->getASTContext()));
214 auto *VD = const_cast<VarDecl *>(AD.getVarDecl());
215 V.handleDestructorCall(VD, DD);
223 V.exitCFGBlockBody(CurrBlock);
225 // Process successors, handling back edges first.
226 if (V.visitSuccessors()) {
227 SmallVector<CFGBlock*, 8> ForwardEdges;
229 // Process successors
230 for (CFGBlock::const_succ_iterator SI = CurrBlock->succ_begin(),
231 SE = CurrBlock->succ_end();
236 if (!VisitedBlocks.alreadySet(*SI)) {
237 ForwardEdges.push_back(*SI);
240 V.handleSuccessorBackEdge(*SI);
243 for (auto *Blk : ForwardEdges)
244 V.handleSuccessor(Blk);
247 V.exitCFGBlock(CurrBlock);
249 V.exitCFG(&CFGraph->getExit());
252 const CFG *getGraph() const { return CFGraph; }
253 CFG *getGraph() { return CFGraph; }
255 const NamedDecl *getDecl() const {
256 return dyn_cast<NamedDecl>(ACtx->getDecl());
259 const PostOrderCFGView *getSortedGraph() const { return SortedGraph; }
262 CFG *CFGraph = nullptr;
263 AnalysisDeclContext *ACtx = nullptr;
264 PostOrderCFGView *SortedGraph = nullptr;
267 // TODO: move this back into ThreadSafety.cpp
268 // This is specific to thread safety. It is here because
269 // translateAttrExpr needs it, but that should be moved too.
270 class CapabilityExpr {
272 /// The capability expression.
273 const til::SExpr* CapExpr;
275 /// True if this is a negative capability.
279 CapabilityExpr(const til::SExpr *E, bool Neg) : CapExpr(E), Negated(Neg) {}
281 const til::SExpr* sexpr() const { return CapExpr; }
282 bool negative() const { return Negated; }
284 CapabilityExpr operator!() const {
285 return CapabilityExpr(CapExpr, !Negated);
288 bool equals(const CapabilityExpr &other) const {
289 return (Negated == other.Negated) && sx::equals(CapExpr, other.CapExpr);
292 bool matches(const CapabilityExpr &other) const {
293 return (Negated == other.Negated) && sx::matches(CapExpr, other.CapExpr);
296 bool matchesUniv(const CapabilityExpr &CapE) const {
297 return isUniversal() || matches(CapE);
300 bool partiallyMatches(const CapabilityExpr &other) const {
301 return (Negated == other.Negated) &&
302 sx::partiallyMatches(CapExpr, other.CapExpr);
305 const ValueDecl* valueDecl() const {
306 if (Negated || CapExpr == nullptr)
308 if (const auto *P = dyn_cast<til::Project>(CapExpr))
309 return P->clangDecl();
310 if (const auto *P = dyn_cast<til::LiteralPtr>(CapExpr))
311 return P->clangDecl();
315 std::string toString() const {
317 return "!" + sx::toString(CapExpr);
318 return sx::toString(CapExpr);
321 bool shouldIgnore() const { return CapExpr == nullptr; }
323 bool isInvalid() const { return sexpr() && isa<til::Undefined>(sexpr()); }
325 bool isUniversal() const { return sexpr() && isa<til::Wildcard>(sexpr()); }
328 // Translate clang::Expr to til::SExpr.
331 /// Encapsulates the lexical context of a function call. The lexical
332 /// context includes the arguments to the call, including the implicit object
333 /// argument. When an attribute containing a mutex expression is attached to
334 /// a method, the expression may refer to formal parameters of the method.
335 /// Actual arguments must be substituted for formal parameters to derive
336 /// the appropriate mutex expression in the lexical context where the function
337 /// is called. PrevCtx holds the context in which the arguments themselves
338 /// should be evaluated; multiple calling contexts can be chained together
339 /// by the lock_returned attribute.
340 struct CallingContext {
341 // The previous context; or 0 if none.
342 CallingContext *Prev;
344 // The decl to which the attr is attached.
345 const NamedDecl *AttrDecl;
347 // Implicit object argument -- e.g. 'this'
348 const Expr *SelfArg = nullptr;
351 unsigned NumArgs = 0;
353 // Function arguments
354 const Expr *const *FunArgs = nullptr;
356 // is Self referred to with -> or .?
357 bool SelfArrow = false;
359 CallingContext(CallingContext *P, const NamedDecl *D = nullptr)
360 : Prev(P), AttrDecl(D) {}
363 SExprBuilder(til::MemRegionRef A) : Arena(A) {
364 // FIXME: we don't always have a self-variable.
365 SelfVar = new (Arena) til::Variable(nullptr);
366 SelfVar->setKind(til::Variable::VK_SFun);
369 // Translate a clang expression in an attribute to a til::SExpr.
370 // Constructs the context from D, DeclExp, and SelfDecl.
371 CapabilityExpr translateAttrExpr(const Expr *AttrExp, const NamedDecl *D,
372 const Expr *DeclExp, VarDecl *SelfD=nullptr);
374 CapabilityExpr translateAttrExpr(const Expr *AttrExp, CallingContext *Ctx);
376 // Translate a clang statement or expression to a TIL expression.
377 // Also performs substitution of variables; Ctx provides the context.
378 // Dispatches on the type of S.
379 til::SExpr *translate(const Stmt *S, CallingContext *Ctx);
380 til::SCFG *buildCFG(CFGWalker &Walker);
382 til::SExpr *lookupStmt(const Stmt *S);
384 til::BasicBlock *lookupBlock(const CFGBlock *B) {
385 return BlockMap[B->getBlockID()];
388 const til::SCFG *getCFG() const { return Scfg; }
389 til::SCFG *getCFG() { return Scfg; }
392 // We implement the CFGVisitor API
393 friend class CFGWalker;
395 til::SExpr *translateDeclRefExpr(const DeclRefExpr *DRE,
396 CallingContext *Ctx) ;
397 til::SExpr *translateCXXThisExpr(const CXXThisExpr *TE, CallingContext *Ctx);
398 til::SExpr *translateMemberExpr(const MemberExpr *ME, CallingContext *Ctx);
399 til::SExpr *translateObjCIVarRefExpr(const ObjCIvarRefExpr *IVRE,
400 CallingContext *Ctx);
401 til::SExpr *translateCallExpr(const CallExpr *CE, CallingContext *Ctx,
402 const Expr *SelfE = nullptr);
403 til::SExpr *translateCXXMemberCallExpr(const CXXMemberCallExpr *ME,
404 CallingContext *Ctx);
405 til::SExpr *translateCXXOperatorCallExpr(const CXXOperatorCallExpr *OCE,
406 CallingContext *Ctx);
407 til::SExpr *translateUnaryOperator(const UnaryOperator *UO,
408 CallingContext *Ctx);
409 til::SExpr *translateBinOp(til::TIL_BinaryOpcode Op,
410 const BinaryOperator *BO,
411 CallingContext *Ctx, bool Reverse = false);
412 til::SExpr *translateBinAssign(til::TIL_BinaryOpcode Op,
413 const BinaryOperator *BO,
414 CallingContext *Ctx, bool Assign = false);
415 til::SExpr *translateBinaryOperator(const BinaryOperator *BO,
416 CallingContext *Ctx);
417 til::SExpr *translateCastExpr(const CastExpr *CE, CallingContext *Ctx);
418 til::SExpr *translateArraySubscriptExpr(const ArraySubscriptExpr *E,
419 CallingContext *Ctx);
420 til::SExpr *translateAbstractConditionalOperator(
421 const AbstractConditionalOperator *C, CallingContext *Ctx);
423 til::SExpr *translateDeclStmt(const DeclStmt *S, CallingContext *Ctx);
425 // Map from statements in the clang CFG to SExprs in the til::SCFG.
426 using StatementMap = llvm::DenseMap<const Stmt *, til::SExpr *>;
428 // Map from clang local variables to indices in a LVarDefinitionMap.
429 using LVarIndexMap = llvm::DenseMap<const ValueDecl *, unsigned>;
431 // Map from local variable indices to SSA variables (or constants).
432 using NameVarPair = std::pair<const ValueDecl *, til::SExpr *>;
433 using LVarDefinitionMap = CopyOnWriteVector<NameVarPair>;
436 LVarDefinitionMap ExitMap;
437 bool HasBackEdges = false;
439 // Successors yet to be processed
440 unsigned UnprocessedSuccessors = 0;
442 // Predecessors already processed
443 unsigned ProcessedPredecessors = 0;
445 BlockInfo() = default;
446 BlockInfo(BlockInfo &&) = default;
447 BlockInfo &operator=(BlockInfo &&) = default;
450 void enterCFG(CFG *Cfg, const NamedDecl *D, const CFGBlock *First);
451 void enterCFGBlock(const CFGBlock *B);
452 bool visitPredecessors() { return true; }
453 void handlePredecessor(const CFGBlock *Pred);
454 void handlePredecessorBackEdge(const CFGBlock *Pred);
455 void enterCFGBlockBody(const CFGBlock *B);
456 void handleStatement(const Stmt *S);
457 void handleDestructorCall(const VarDecl *VD, const CXXDestructorDecl *DD);
458 void exitCFGBlockBody(const CFGBlock *B);
459 bool visitSuccessors() { return true; }
460 void handleSuccessor(const CFGBlock *Succ);
461 void handleSuccessorBackEdge(const CFGBlock *Succ);
462 void exitCFGBlock(const CFGBlock *B);
463 void exitCFG(const CFGBlock *Last);
465 void insertStmt(const Stmt *S, til::SExpr *E) {
466 SMap.insert(std::make_pair(S, E));
469 til::SExpr *getCurrentLVarDefinition(const ValueDecl *VD);
471 til::SExpr *addStatement(til::SExpr *E, const Stmt *S,
472 const ValueDecl *VD = nullptr);
473 til::SExpr *lookupVarDecl(const ValueDecl *VD);
474 til::SExpr *addVarDecl(const ValueDecl *VD, til::SExpr *E);
475 til::SExpr *updateVarDecl(const ValueDecl *VD, til::SExpr *E);
477 void makePhiNodeVar(unsigned i, unsigned NPreds, til::SExpr *E);
478 void mergeEntryMap(LVarDefinitionMap Map);
479 void mergeEntryMapBackEdge();
480 void mergePhiNodesBackEdge(const CFGBlock *Blk);
483 // Set to true when parsing capability expressions, which get translated
484 // inaccurately in order to hack around smart pointers etc.
485 static const bool CapabilityExprMode = true;
487 til::MemRegionRef Arena;
489 // Variable to use for 'this'. May be null.
490 til::Variable *SelfVar = nullptr;
492 til::SCFG *Scfg = nullptr;
494 // Map from Stmt to TIL Variables
497 // Indices of clang local vars.
498 LVarIndexMap LVarIdxMap;
500 // Map from clang to til BBs.
501 std::vector<til::BasicBlock *> BlockMap;
503 // Extra information per BB. Indexed by clang BlockID.
504 std::vector<BlockInfo> BBInfo;
506 LVarDefinitionMap CurrentLVarMap;
507 std::vector<til::Phi *> CurrentArguments;
508 std::vector<til::SExpr *> CurrentInstructions;
509 std::vector<til::Phi *> IncompleteArgs;
510 til::BasicBlock *CurrentBB = nullptr;
511 BlockInfo *CurrentBlockInfo = nullptr;
514 // Dump an SCFG to llvm::errs().
515 void printSCFG(CFGWalker &Walker);
517 } // namespace threadSafety
520 #endif // LLVM_CLANG_THREAD_SAFETY_COMMON_H