contrib/llvm/tools/clang/lib/Analysis/AnalysisDeclContext.cpp

   1 //== AnalysisDeclContext.cpp - Analysis context for Path Sens analysis -*- C++ -*-//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file defines AnalysisDeclContext, a class that manages the analysis context
  11 // data for path sensitive analysis.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "clang/Analysis/AnalysisContext.h"
  16 #include "BodyFarm.h"
  17 #include "clang/AST/ASTContext.h"
  18 #include "clang/AST/Decl.h"
  19 #include "clang/AST/DeclObjC.h"
  20 #include "clang/AST/DeclTemplate.h"
  21 #include "clang/AST/ParentMap.h"
  22 #include "clang/AST/StmtVisitor.h"
  23 #include "clang/Analysis/Analyses/CFGReachabilityAnalysis.h"
  24 #include "clang/Analysis/Analyses/LiveVariables.h"
  25 #include "clang/Analysis/Analyses/PseudoConstantAnalysis.h"
  26 #include "clang/Analysis/CFG.h"
  27 #include "clang/Analysis/CFGStmtMap.h"
  28 #include "clang/Analysis/Support/BumpVector.h"
  29 #include "llvm/ADT/SmallPtrSet.h"
  30 #include "llvm/Support/ErrorHandling.h"
  31 #include "llvm/Support/SaveAndRestore.h"
  32 #include "llvm/Support/raw_ostream.h"
  33
  34 using namespace clang;
  35
  36 typedef llvm::DenseMap<const void *, ManagedAnalysis *> ManagedAnalysisMap;
  37
  38 AnalysisDeclContext::AnalysisDeclContext(AnalysisDeclContextManager *Mgr,
  39                                          const Decl *d,
  40                                          const CFG::BuildOptions &buildOptions)
  41   : Manager(Mgr),
  42     D(d),
  43     cfgBuildOptions(buildOptions),
  44     forcedBlkExprs(nullptr),
  45     builtCFG(false),
  46     builtCompleteCFG(false),
  47     ReferencedBlockVars(nullptr),
  48     ManagedAnalyses(nullptr)
  49 {
  50   cfgBuildOptions.forcedBlkExprs = &forcedBlkExprs;
  51 }
  52
  53 AnalysisDeclContext::AnalysisDeclContext(AnalysisDeclContextManager *Mgr,
  54                                          const Decl *d)
  55 : Manager(Mgr),
  56   D(d),
  57   forcedBlkExprs(nullptr),
  58   builtCFG(false),
  59   builtCompleteCFG(false),
  60   ReferencedBlockVars(nullptr),
  61   ManagedAnalyses(nullptr)
  62 {
  63   cfgBuildOptions.forcedBlkExprs = &forcedBlkExprs;
  64 }
  65
  66 AnalysisDeclContextManager::AnalysisDeclContextManager(bool useUnoptimizedCFG,
  67                                                        bool addImplicitDtors,
  68                                                        bool addInitializers,
  69                                                        bool addTemporaryDtors,
  70                                                        bool synthesizeBodies,
  71                                                        bool addStaticInitBranch,
  72                                                        bool addCXXNewAllocator,
  73                                                        CodeInjector *injector)
  74   : Injector(injector), SynthesizeBodies(synthesizeBodies)
  75 {
  76   cfgBuildOptions.PruneTriviallyFalseEdges = !useUnoptimizedCFG;
  77   cfgBuildOptions.AddImplicitDtors = addImplicitDtors;
  78   cfgBuildOptions.AddInitializers = addInitializers;
  79   cfgBuildOptions.AddTemporaryDtors = addTemporaryDtors;
  80   cfgBuildOptions.AddStaticInitBranches = addStaticInitBranch;
  81   cfgBuildOptions.AddCXXNewAllocator = addCXXNewAllocator;
  82 }
  83
  84 void AnalysisDeclContextManager::clear() {
  85   llvm::DeleteContainerSeconds(Contexts);
  86 }
  87
  88 static BodyFarm &getBodyFarm(ASTContext &C, CodeInjector *injector = nullptr) {
  89   static BodyFarm *BF = new BodyFarm(C, injector);
  90   return *BF;
  91 }
  92
  93 Stmt *AnalysisDeclContext::getBody(bool &IsAutosynthesized) const {
  94   IsAutosynthesized = false;
  95   if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
  96     Stmt *Body = FD->getBody();
  97     if (!Body && Manager && Manager->synthesizeBodies()) {
  98       Body = getBodyFarm(getASTContext(), Manager->Injector.get()).getBody(FD);
  99       if (Body)
 100         IsAutosynthesized = true;
 101     }
 102     return Body;
 103   }
 104   else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
 105     Stmt *Body = MD->getBody();
 106     if (!Body && Manager && Manager->synthesizeBodies()) {
 107       Body = getBodyFarm(getASTContext(), Manager->Injector.get()).getBody(MD);
 108       if (Body)
 109         IsAutosynthesized = true;
 110     }
 111     return Body;
 112   } else if (const BlockDecl *BD = dyn_cast<BlockDecl>(D))
 113     return BD->getBody();
 114   else if (const FunctionTemplateDecl *FunTmpl
 115            = dyn_cast_or_null<FunctionTemplateDecl>(D))
 116     return FunTmpl->getTemplatedDecl()->getBody();
 117
 118   llvm_unreachable("unknown code decl");
 119 }
 120
 121 Stmt *AnalysisDeclContext::getBody() const {
 122   bool Tmp;
 123   return getBody(Tmp);
 124 }
 125
 126 bool AnalysisDeclContext::isBodyAutosynthesized() const {
 127   bool Tmp;
 128   getBody(Tmp);
 129   return Tmp;
 130 }
 131
 132 bool AnalysisDeclContext::isBodyAutosynthesizedFromModelFile() const {
 133   bool Tmp;
 134   Stmt *Body = getBody(Tmp);
 135   return Tmp && Body->getLocStart().isValid();
 136 }
 137
 138
 139 const ImplicitParamDecl *AnalysisDeclContext::getSelfDecl() const {
 140   if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D))
 141     return MD->getSelfDecl();
 142   if (const BlockDecl *BD = dyn_cast<BlockDecl>(D)) {
 143     // See if 'self' was captured by the block.
 144     for (const auto &I : BD->captures()) {
 145       const VarDecl *VD = I.getVariable();
 146       if (VD->getName() == "self")
 147         return dyn_cast<ImplicitParamDecl>(VD);
 148     }
 149   }
 150
 151   return nullptr;
 152 }
 153
 154 void AnalysisDeclContext::registerForcedBlockExpression(const Stmt *stmt) {
 155   if (!forcedBlkExprs)
 156     forcedBlkExprs = new CFG::BuildOptions::ForcedBlkExprs();
 157   // Default construct an entry for 'stmt'.
 158   if (const Expr *e = dyn_cast<Expr>(stmt))
 159     stmt = e->IgnoreParens();
 160   (void) (*forcedBlkExprs)[stmt];
 161 }
 162
 163 const CFGBlock *
 164 AnalysisDeclContext::getBlockForRegisteredExpression(const Stmt *stmt) {
 165   assert(forcedBlkExprs);
 166   if (const Expr *e = dyn_cast<Expr>(stmt))
 167     stmt = e->IgnoreParens();
 168   CFG::BuildOptions::ForcedBlkExprs::const_iterator itr =
 169     forcedBlkExprs->find(stmt);
 170   assert(itr != forcedBlkExprs->end());
 171   return itr->second;
 172 }
 173
 174 /// Add each synthetic statement in the CFG to the parent map, using the
 175 /// source statement's parent.
 176 static void addParentsForSyntheticStmts(const CFG *TheCFG, ParentMap &PM) {
 177   if (!TheCFG)
 178     return;
 179
 180   for (CFG::synthetic_stmt_iterator I = TheCFG->synthetic_stmt_begin(),
 181                                     E = TheCFG->synthetic_stmt_end();
 182        I != E; ++I) {
 183     PM.setParent(I->first, PM.getParent(I->second));
 184   }
 185 }
 186
 187 CFG *AnalysisDeclContext::getCFG() {
 188   if (!cfgBuildOptions.PruneTriviallyFalseEdges)
 189     return getUnoptimizedCFG();
 190
 191   if (!builtCFG) {
 192     cfg = CFG::buildCFG(D, getBody(), &D->getASTContext(), cfgBuildOptions);
 193     // Even when the cfg is not successfully built, we don't
 194     // want to try building it again.
 195     builtCFG = true;
 196
 197     if (PM)
 198       addParentsForSyntheticStmts(cfg.get(), *PM);
 199
 200     // The Observer should only observe one build of the CFG.
 201     getCFGBuildOptions().Observer = nullptr;
 202   }
 203   return cfg.get();
 204 }
 205
 206 CFG *AnalysisDeclContext::getUnoptimizedCFG() {
 207   if (!builtCompleteCFG) {
 208     SaveAndRestore<bool> NotPrune(cfgBuildOptions.PruneTriviallyFalseEdges,
 209                                   false);
 210     completeCFG =
 211         CFG::buildCFG(D, getBody(), &D->getASTContext(), cfgBuildOptions);
 212     // Even when the cfg is not successfully built, we don't
 213     // want to try building it again.
 214     builtCompleteCFG = true;
 215
 216     if (PM)
 217       addParentsForSyntheticStmts(completeCFG.get(), *PM);
 218
 219     // The Observer should only observe one build of the CFG.
 220     getCFGBuildOptions().Observer = nullptr;
 221   }
 222   return completeCFG.get();
 223 }
 224
 225 CFGStmtMap *AnalysisDeclContext::getCFGStmtMap() {
 226   if (cfgStmtMap)
 227     return cfgStmtMap.get();
 228
 229   if (CFG *c = getCFG()) {
 230     cfgStmtMap.reset(CFGStmtMap::Build(c, &getParentMap()));
 231     return cfgStmtMap.get();
 232   }
 233
 234   return nullptr;
 235 }
 236
 237 CFGReverseBlockReachabilityAnalysis *AnalysisDeclContext::getCFGReachablityAnalysis() {
 238   if (CFA)
 239     return CFA.get();
 240
 241   if (CFG *c = getCFG()) {
 242     CFA.reset(new CFGReverseBlockReachabilityAnalysis(*c));
 243     return CFA.get();
 244   }
 245
 246   return nullptr;
 247 }
 248
 249 void AnalysisDeclContext::dumpCFG(bool ShowColors) {
 250     getCFG()->dump(getASTContext().getLangOpts(), ShowColors);
 251 }
 252
 253 ParentMap &AnalysisDeclContext::getParentMap() {
 254   if (!PM) {
 255     PM.reset(new ParentMap(getBody()));
 256     if (const CXXConstructorDecl *C = dyn_cast<CXXConstructorDecl>(getDecl())) {
 257       for (const auto *I : C->inits()) {
 258         PM->addStmt(I->getInit());
 259       }
 260     }
 261     if (builtCFG)
 262       addParentsForSyntheticStmts(getCFG(), *PM);
 263     if (builtCompleteCFG)
 264       addParentsForSyntheticStmts(getUnoptimizedCFG(), *PM);
 265   }
 266   return *PM;
 267 }
 268
 269 PseudoConstantAnalysis *AnalysisDeclContext::getPseudoConstantAnalysis() {
 270   if (!PCA)
 271     PCA.reset(new PseudoConstantAnalysis(getBody()));
 272   return PCA.get();
 273 }
 274
 275 AnalysisDeclContext *AnalysisDeclContextManager::getContext(const Decl *D) {
 276   if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
 277     // Calling 'hasBody' replaces 'FD' in place with the FunctionDecl
 278     // that has the body.
 279     FD->hasBody(FD);
 280     D = FD;
 281   }
 282
 283   AnalysisDeclContext *&AC = Contexts[D];
 284   if (!AC)
 285     AC = new AnalysisDeclContext(this, D, cfgBuildOptions);
 286   return AC;
 287 }
 288
 289 const StackFrameContext *
 290 AnalysisDeclContext::getStackFrame(LocationContext const *Parent, const Stmt *S,
 291                                const CFGBlock *Blk, unsigned Idx) {
 292   return getLocationContextManager().getStackFrame(this, Parent, S, Blk, Idx);
 293 }
 294
 295 const BlockInvocationContext *
 296 AnalysisDeclContext::getBlockInvocationContext(const LocationContext *parent,
 297                                                const clang::BlockDecl *BD,
 298                                                const void *ContextData) {
 299   return getLocationContextManager().getBlockInvocationContext(this, parent,
 300                                                                BD, ContextData);
 301 }
 302
 303 LocationContextManager & AnalysisDeclContext::getLocationContextManager() {
 304   assert(Manager &&
 305          "Cannot create LocationContexts without an AnalysisDeclContextManager!");
 306   return Manager->getLocationContextManager();
 307 }
 308
 309 //===----------------------------------------------------------------------===//
 310 // FoldingSet profiling.
 311 //===----------------------------------------------------------------------===//
 312
 313 void LocationContext::ProfileCommon(llvm::FoldingSetNodeID &ID,
 314                                     ContextKind ck,
 315                                     AnalysisDeclContext *ctx,
 316                                     const LocationContext *parent,
 317                                     const void *data) {
 318   ID.AddInteger(ck);
 319   ID.AddPointer(ctx);
 320   ID.AddPointer(parent);
 321   ID.AddPointer(data);
 322 }
 323
 324 void StackFrameContext::Profile(llvm::FoldingSetNodeID &ID) {
 325   Profile(ID, getAnalysisDeclContext(), getParent(), CallSite, Block, Index);
 326 }
 327
 328 void ScopeContext::Profile(llvm::FoldingSetNodeID &ID) {
 329   Profile(ID, getAnalysisDeclContext(), getParent(), Enter);
 330 }
 331
 332 void BlockInvocationContext::Profile(llvm::FoldingSetNodeID &ID) {
 333   Profile(ID, getAnalysisDeclContext(), getParent(), BD, ContextData);
 334 }
 335
 336 //===----------------------------------------------------------------------===//
 337 // LocationContext creation.
 338 //===----------------------------------------------------------------------===//
 339
 340 template <typename LOC, typename DATA>
 341 const LOC*
 342 LocationContextManager::getLocationContext(AnalysisDeclContext *ctx,
 343                                            const LocationContext *parent,
 344                                            const DATA *d) {
 345   llvm::FoldingSetNodeID ID;
 346   LOC::Profile(ID, ctx, parent, d);
 347   void *InsertPos;
 348
 349   LOC *L = cast_or_null<LOC>(Contexts.FindNodeOrInsertPos(ID, InsertPos));
 350
 351   if (!L) {
 352     L = new LOC(ctx, parent, d);
 353     Contexts.InsertNode(L, InsertPos);
 354   }
 355   return L;
 356 }
 357
 358 const StackFrameContext*
 359 LocationContextManager::getStackFrame(AnalysisDeclContext *ctx,
 360                                       const LocationContext *parent,
 361                                       const Stmt *s,
 362                                       const CFGBlock *blk, unsigned idx) {
 363   llvm::FoldingSetNodeID ID;
 364   StackFrameContext::Profile(ID, ctx, parent, s, blk, idx);
 365   void *InsertPos;
 366   StackFrameContext *L =
 367    cast_or_null<StackFrameContext>(Contexts.FindNodeOrInsertPos(ID, InsertPos));
 368   if (!L) {
 369     L = new StackFrameContext(ctx, parent, s, blk, idx);
 370     Contexts.InsertNode(L, InsertPos);
 371   }
 372   return L;
 373 }
 374
 375 const ScopeContext *
 376 LocationContextManager::getScope(AnalysisDeclContext *ctx,
 377                                  const LocationContext *parent,
 378                                  const Stmt *s) {
 379   return getLocationContext<ScopeContext, Stmt>(ctx, parent, s);
 380 }
 381
 382 const BlockInvocationContext *
 383 LocationContextManager::getBlockInvocationContext(AnalysisDeclContext *ctx,
 384                                                   const LocationContext *parent,
 385                                                   const BlockDecl *BD,
 386                                                   const void *ContextData) {
 387   llvm::FoldingSetNodeID ID;
 388   BlockInvocationContext::Profile(ID, ctx, parent, BD, ContextData);
 389   void *InsertPos;
 390   BlockInvocationContext *L =
 391     cast_or_null<BlockInvocationContext>(Contexts.FindNodeOrInsertPos(ID,
 392                                                                     InsertPos));
 393   if (!L) {
 394     L = new BlockInvocationContext(ctx, parent, BD, ContextData);
 395     Contexts.InsertNode(L, InsertPos);
 396   }
 397   return L;
 398 }
 399
 400 //===----------------------------------------------------------------------===//
 401 // LocationContext methods.
 402 //===----------------------------------------------------------------------===//
 403
 404 const StackFrameContext *LocationContext::getCurrentStackFrame() const {
 405   const LocationContext *LC = this;
 406   while (LC) {
 407     if (const StackFrameContext *SFC = dyn_cast<StackFrameContext>(LC))
 408       return SFC;
 409     LC = LC->getParent();
 410   }
 411   return nullptr;
 412 }
 413
 414 bool LocationContext::inTopFrame() const {
 415   return getCurrentStackFrame()->inTopFrame();
 416 }
 417
 418 bool LocationContext::isParentOf(const LocationContext *LC) const {
 419   do {
 420     const LocationContext *Parent = LC->getParent();
 421     if (Parent == this)
 422       return true;
 423     else
 424       LC = Parent;
 425   } while (LC);
 426
 427   return false;
 428 }
 429
 430 void LocationContext::dumpStack(raw_ostream &OS, StringRef Indent) const {
 431   ASTContext &Ctx = getAnalysisDeclContext()->getASTContext();
 432   PrintingPolicy PP(Ctx.getLangOpts());
 433   PP.TerseOutput = 1;
 434
 435   unsigned Frame = 0;
 436   for (const LocationContext *LCtx = this; LCtx; LCtx = LCtx->getParent()) {
 437     switch (LCtx->getKind()) {
 438     case StackFrame:
 439       OS << Indent << '#' << Frame++ << ' ';
 440       cast<StackFrameContext>(LCtx)->getDecl()->print(OS, PP);
 441       OS << '\n';
 442       break;
 443     case Scope:
 444       OS << Indent << "    (scope)\n";
 445       break;
 446     case Block:
 447       OS << Indent << "    (block context: "
 448                    << cast<BlockInvocationContext>(LCtx)->getContextData()
 449                    << ")\n";
 450       break;
 451     }
 452   }
 453 }
 454
 455 LLVM_DUMP_METHOD void LocationContext::dumpStack() const {
 456   dumpStack(llvm::errs());
 457 }
 458
 459 //===----------------------------------------------------------------------===//
 460 // Lazily generated map to query the external variables referenced by a Block.
 461 //===----------------------------------------------------------------------===//
 462
 463 namespace {
 464 class FindBlockDeclRefExprsVals : public StmtVisitor<FindBlockDeclRefExprsVals>{
 465   BumpVector<const VarDecl*> &BEVals;
 466   BumpVectorContext &BC;
 467   llvm::SmallPtrSet<const VarDecl*, 4> Visited;
 468   llvm::SmallPtrSet<const DeclContext*, 4> IgnoredContexts;
 469 public:
 470   FindBlockDeclRefExprsVals(BumpVector<const VarDecl*> &bevals,
 471                             BumpVectorContext &bc)
 472   : BEVals(bevals), BC(bc) {}
 473
 474   void VisitStmt(Stmt *S) {
 475     for (Stmt::child_range I = S->children(); I; ++I)
 476       if (Stmt *child = *I)
 477         Visit(child);
 478   }
 479
 480   void VisitDeclRefExpr(DeclRefExpr *DR) {
 481     // Non-local variables are also directly modified.
 482     if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) {
 483       if (!VD->hasLocalStorage()) {
 484         if (Visited.insert(VD).second)
 485           BEVals.push_back(VD, BC);
 486       }
 487     }
 488   }
 489
 490   void VisitBlockExpr(BlockExpr *BR) {
 491     // Blocks containing blocks can transitively capture more variables.
 492     IgnoredContexts.insert(BR->getBlockDecl());
 493     Visit(BR->getBlockDecl()->getBody());
 494   }
 495
 496   void VisitPseudoObjectExpr(PseudoObjectExpr *PE) {
 497     for (PseudoObjectExpr::semantics_iterator it = PE->semantics_begin(),
 498          et = PE->semantics_end(); it != et; ++it) {
 499       Expr *Semantic = *it;
 500       if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic))
 501         Semantic = OVE->getSourceExpr();
 502       Visit(Semantic);
 503     }
 504   }
 505 };
 506 } // end anonymous namespace
 507
 508 typedef BumpVector<const VarDecl*> DeclVec;
 509
 510 static DeclVec* LazyInitializeReferencedDecls(const BlockDecl *BD,
 511                                               void *&Vec,
 512                                               llvm::BumpPtrAllocator &A) {
 513   if (Vec)
 514     return (DeclVec*) Vec;
 515
 516   BumpVectorContext BC(A);
 517   DeclVec *BV = (DeclVec*) A.Allocate<DeclVec>();
 518   new (BV) DeclVec(BC, 10);
 519
 520   // Go through the capture list.
 521   for (const auto &CI : BD->captures()) {
 522     BV->push_back(CI.getVariable(), BC);
 523   }
 524
 525   // Find the referenced global/static variables.
 526   FindBlockDeclRefExprsVals F(*BV, BC);
 527   F.Visit(BD->getBody());
 528
 529   Vec = BV;
 530   return BV;
 531 }
 532
 533 std::pair<AnalysisDeclContext::referenced_decls_iterator,
 534           AnalysisDeclContext::referenced_decls_iterator>
 535 AnalysisDeclContext::getReferencedBlockVars(const BlockDecl *BD) {
 536   if (!ReferencedBlockVars)
 537     ReferencedBlockVars = new llvm::DenseMap<const BlockDecl*,void*>();
 538
 539   DeclVec *V = LazyInitializeReferencedDecls(BD, (*ReferencedBlockVars)[BD], A);
 540   return std::make_pair(V->begin(), V->end());
 541 }
 542
 543 ManagedAnalysis *&AnalysisDeclContext::getAnalysisImpl(const void *tag) {
 544   if (!ManagedAnalyses)
 545     ManagedAnalyses = new ManagedAnalysisMap();
 546   ManagedAnalysisMap *M = (ManagedAnalysisMap*) ManagedAnalyses;
 547   return (*M)[tag];
 548 }
 549
 550 //===----------------------------------------------------------------------===//
 551 // Cleanup.
 552 //===----------------------------------------------------------------------===//
 553
 554 ManagedAnalysis::~ManagedAnalysis() {}
 555
 556 AnalysisDeclContext::~AnalysisDeclContext() {
 557   delete forcedBlkExprs;
 558   delete ReferencedBlockVars;
 559   // Release the managed analyses.
 560   if (ManagedAnalyses) {
 561     ManagedAnalysisMap *M = (ManagedAnalysisMap*) ManagedAnalyses;
 562     llvm::DeleteContainerSeconds(*M);
 563     delete M;
 564   }
 565 }
 566
 567 AnalysisDeclContextManager::~AnalysisDeclContextManager() {
 568   llvm::DeleteContainerSeconds(Contexts);
 569 }
 570
 571 LocationContext::~LocationContext() {}
 572
 573 LocationContextManager::~LocationContextManager() {
 574   clear();
 575 }
 576
 577 void LocationContextManager::clear() {
 578   for (llvm::FoldingSet<LocationContext>::iterator I = Contexts.begin(),
 579        E = Contexts.end(); I != E; ) {
 580     LocationContext *LC = &*I;
 581     ++I;
 582     delete LC;
 583   }
 584
 585   Contexts.clear();
 586 }
 587