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