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/AST/ASTContext.h"
  16 #include "clang/AST/Decl.h"
  17 #include "clang/AST/DeclObjC.h"
  18 #include "clang/AST/DeclTemplate.h"
  19 #include "clang/AST/ParentMap.h"
  20 #include "clang/AST/StmtVisitor.h"
  21 #include "clang/Analysis/Analyses/LiveVariables.h"
  22 #include "clang/Analysis/Analyses/PseudoConstantAnalysis.h"
  23 #include "clang/Analysis/Analyses/CFGReachabilityAnalysis.h"
  24 #include "clang/Analysis/AnalysisContext.h"
  25 #include "clang/Analysis/CFG.h"
  26 #include "clang/Analysis/CFGStmtMap.h"
  27 #include "clang/Analysis/Support/BumpVector.h"
  28 #include "llvm/Support/SaveAndRestore.h"
  29 #include "llvm/ADT/SmallPtrSet.h"
  30 #include "llvm/Support/ErrorHandling.h"
  31
  32 #include "BodyFarm.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(0),
  45     builtCFG(false),
  46     builtCompleteCFG(false),
  47     ReferencedBlockVars(0),
  48     ManagedAnalyses(0)
  49 {
  50   cfgBuildOptions.forcedBlkExprs = &forcedBlkExprs;
  51 }
  52
  53 AnalysisDeclContext::AnalysisDeclContext(AnalysisDeclContextManager *Mgr,
  54                                          const Decl *d)
  55 : Manager(Mgr),
  56   D(d),
  57   forcedBlkExprs(0),
  58   builtCFG(false),
  59   builtCompleteCFG(false),
  60   ReferencedBlockVars(0),
  61   ManagedAnalyses(0)
  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   : SynthesizeBodies(synthesizeBodies)
  72 {
  73   cfgBuildOptions.PruneTriviallyFalseEdges = !useUnoptimizedCFG;
  74   cfgBuildOptions.AddImplicitDtors = addImplicitDtors;
  75   cfgBuildOptions.AddInitializers = addInitializers;
  76   cfgBuildOptions.AddTemporaryDtors = addTemporaryDtors;
  77 }
  78
  79 void AnalysisDeclContextManager::clear() {
  80   for (ContextMap::iterator I = Contexts.begin(), E = Contexts.end(); I!=E; ++I)
  81     delete I->second;
  82   Contexts.clear();
  83 }
  84
  85 static BodyFarm &getBodyFarm(ASTContext &C) {
  86   static BodyFarm *BF = new BodyFarm(C);
  87   return *BF;
  88 }
  89
  90 Stmt *AnalysisDeclContext::getBody() const {
  91   if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
  92     Stmt *Body = FD->getBody();
  93     if (!Body && Manager && Manager->synthesizeBodies())
  94       return getBodyFarm(getASTContext()).getBody(FD);
  95     return Body;
  96   }
  97   else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D))
  98     return MD->getBody();
  99   else if (const BlockDecl *BD = dyn_cast<BlockDecl>(D))
 100     return BD->getBody();
 101   else if (const FunctionTemplateDecl *FunTmpl
 102            = dyn_cast_or_null<FunctionTemplateDecl>(D))
 103     return FunTmpl->getTemplatedDecl()->getBody();
 104
 105   llvm_unreachable("unknown code decl");
 106 }
 107
 108 const ImplicitParamDecl *AnalysisDeclContext::getSelfDecl() const {
 109   if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D))
 110     return MD->getSelfDecl();
 111   if (const BlockDecl *BD = dyn_cast<BlockDecl>(D)) {
 112     // See if 'self' was captured by the block.
 113     for (BlockDecl::capture_const_iterator it = BD->capture_begin(),
 114          et = BD->capture_end(); it != et; ++it) {
 115       const VarDecl *VD = it->getVariable();
 116       if (VD->getName() == "self")
 117         return dyn_cast<ImplicitParamDecl>(VD);
 118     }
 119   }
 120
 121   return NULL;
 122 }
 123
 124 void AnalysisDeclContext::registerForcedBlockExpression(const Stmt *stmt) {
 125   if (!forcedBlkExprs)
 126     forcedBlkExprs = new CFG::BuildOptions::ForcedBlkExprs();
 127   // Default construct an entry for 'stmt'.
 128   if (const Expr *e = dyn_cast<Expr>(stmt))
 129     stmt = e->IgnoreParens();
 130   (void) (*forcedBlkExprs)[stmt];
 131 }
 132
 133 const CFGBlock *
 134 AnalysisDeclContext::getBlockForRegisteredExpression(const Stmt *stmt) {
 135   assert(forcedBlkExprs);
 136   if (const Expr *e = dyn_cast<Expr>(stmt))
 137     stmt = e->IgnoreParens();
 138   CFG::BuildOptions::ForcedBlkExprs::const_iterator itr =
 139     forcedBlkExprs->find(stmt);
 140   assert(itr != forcedBlkExprs->end());
 141   return itr->second;
 142 }
 143
 144 CFG *AnalysisDeclContext::getCFG() {
 145   if (!cfgBuildOptions.PruneTriviallyFalseEdges)
 146     return getUnoptimizedCFG();
 147
 148   if (!builtCFG) {
 149     cfg.reset(CFG::buildCFG(D, getBody(),
 150                             &D->getASTContext(), cfgBuildOptions));
 151     // Even when the cfg is not successfully built, we don't
 152     // want to try building it again.
 153     builtCFG = true;
 154   }
 155   return cfg.get();
 156 }
 157
 158 CFG *AnalysisDeclContext::getUnoptimizedCFG() {
 159   if (!builtCompleteCFG) {
 160     SaveAndRestore<bool> NotPrune(cfgBuildOptions.PruneTriviallyFalseEdges,
 161                                   false);
 162     completeCFG.reset(CFG::buildCFG(D, getBody(), &D->getASTContext(),
 163                                     cfgBuildOptions));
 164     // Even when the cfg is not successfully built, we don't
 165     // want to try building it again.
 166     builtCompleteCFG = true;
 167   }
 168   return completeCFG.get();
 169 }
 170
 171 CFGStmtMap *AnalysisDeclContext::getCFGStmtMap() {
 172   if (cfgStmtMap)
 173     return cfgStmtMap.get();
 174
 175   if (CFG *c = getCFG()) {
 176     cfgStmtMap.reset(CFGStmtMap::Build(c, &getParentMap()));
 177     return cfgStmtMap.get();
 178   }
 179
 180   return 0;
 181 }
 182
 183 CFGReverseBlockReachabilityAnalysis *AnalysisDeclContext::getCFGReachablityAnalysis() {
 184   if (CFA)
 185     return CFA.get();
 186
 187   if (CFG *c = getCFG()) {
 188     CFA.reset(new CFGReverseBlockReachabilityAnalysis(*c));
 189     return CFA.get();
 190   }
 191
 192   return 0;
 193 }
 194
 195 void AnalysisDeclContext::dumpCFG(bool ShowColors) {
 196     getCFG()->dump(getASTContext().getLangOpts(), ShowColors);
 197 }
 198
 199 ParentMap &AnalysisDeclContext::getParentMap() {
 200   if (!PM) {
 201     PM.reset(new ParentMap(getBody()));
 202     if (const CXXConstructorDecl *C = dyn_cast<CXXConstructorDecl>(getDecl())) {
 203       for (CXXConstructorDecl::init_const_iterator I = C->init_begin(),
 204                                                    E = C->init_end();
 205            I != E; ++I) {
 206         PM->addStmt((*I)->getInit());
 207       }
 208     }
 209   }
 210   return *PM;
 211 }
 212
 213 PseudoConstantAnalysis *AnalysisDeclContext::getPseudoConstantAnalysis() {
 214   if (!PCA)
 215     PCA.reset(new PseudoConstantAnalysis(getBody()));
 216   return PCA.get();
 217 }
 218
 219 AnalysisDeclContext *AnalysisDeclContextManager::getContext(const Decl *D) {
 220   if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
 221     // Calling 'hasBody' replaces 'FD' in place with the FunctionDecl
 222     // that has the body.
 223     FD->hasBody(FD);
 224     D = FD;
 225   }
 226
 227   AnalysisDeclContext *&AC = Contexts[D];
 228   if (!AC)
 229     AC = new AnalysisDeclContext(this, D, cfgBuildOptions);
 230   return AC;
 231 }
 232
 233 const StackFrameContext *
 234 AnalysisDeclContext::getStackFrame(LocationContext const *Parent, const Stmt *S,
 235                                const CFGBlock *Blk, unsigned Idx) {
 236   return getLocationContextManager().getStackFrame(this, Parent, S, Blk, Idx);
 237 }
 238
 239 const BlockInvocationContext *
 240 AnalysisDeclContext::getBlockInvocationContext(const LocationContext *parent,
 241                                                const clang::BlockDecl *BD,
 242                                                const void *ContextData) {
 243   return getLocationContextManager().getBlockInvocationContext(this, parent,
 244                                                                BD, ContextData);
 245 }
 246
 247 LocationContextManager & AnalysisDeclContext::getLocationContextManager() {
 248   assert(Manager &&
 249          "Cannot create LocationContexts without an AnalysisDeclContextManager!");
 250   return Manager->getLocationContextManager();
 251 }
 252
 253 //===----------------------------------------------------------------------===//
 254 // FoldingSet profiling.
 255 //===----------------------------------------------------------------------===//
 256
 257 void LocationContext::ProfileCommon(llvm::FoldingSetNodeID &ID,
 258                                     ContextKind ck,
 259                                     AnalysisDeclContext *ctx,
 260                                     const LocationContext *parent,
 261                                     const void *data) {
 262   ID.AddInteger(ck);
 263   ID.AddPointer(ctx);
 264   ID.AddPointer(parent);
 265   ID.AddPointer(data);
 266 }
 267
 268 void StackFrameContext::Profile(llvm::FoldingSetNodeID &ID) {
 269   Profile(ID, getAnalysisDeclContext(), getParent(), CallSite, Block, Index);
 270 }
 271
 272 void ScopeContext::Profile(llvm::FoldingSetNodeID &ID) {
 273   Profile(ID, getAnalysisDeclContext(), getParent(), Enter);
 274 }
 275
 276 void BlockInvocationContext::Profile(llvm::FoldingSetNodeID &ID) {
 277   Profile(ID, getAnalysisDeclContext(), getParent(), BD, ContextData);
 278 }
 279
 280 //===----------------------------------------------------------------------===//
 281 // LocationContext creation.
 282 //===----------------------------------------------------------------------===//
 283
 284 template <typename LOC, typename DATA>
 285 const LOC*
 286 LocationContextManager::getLocationContext(AnalysisDeclContext *ctx,
 287                                            const LocationContext *parent,
 288                                            const DATA *d) {
 289   llvm::FoldingSetNodeID ID;
 290   LOC::Profile(ID, ctx, parent, d);
 291   void *InsertPos;
 292
 293   LOC *L = cast_or_null<LOC>(Contexts.FindNodeOrInsertPos(ID, InsertPos));
 294
 295   if (!L) {
 296     L = new LOC(ctx, parent, d);
 297     Contexts.InsertNode(L, InsertPos);
 298   }
 299   return L;
 300 }
 301
 302 const StackFrameContext*
 303 LocationContextManager::getStackFrame(AnalysisDeclContext *ctx,
 304                                       const LocationContext *parent,
 305                                       const Stmt *s,
 306                                       const CFGBlock *blk, unsigned idx) {
 307   llvm::FoldingSetNodeID ID;
 308   StackFrameContext::Profile(ID, ctx, parent, s, blk, idx);
 309   void *InsertPos;
 310   StackFrameContext *L =
 311    cast_or_null<StackFrameContext>(Contexts.FindNodeOrInsertPos(ID, InsertPos));
 312   if (!L) {
 313     L = new StackFrameContext(ctx, parent, s, blk, idx);
 314     Contexts.InsertNode(L, InsertPos);
 315   }
 316   return L;
 317 }
 318
 319 const ScopeContext *
 320 LocationContextManager::getScope(AnalysisDeclContext *ctx,
 321                                  const LocationContext *parent,
 322                                  const Stmt *s) {
 323   return getLocationContext<ScopeContext, Stmt>(ctx, parent, s);
 324 }
 325
 326 const BlockInvocationContext *
 327 LocationContextManager::getBlockInvocationContext(AnalysisDeclContext *ctx,
 328                                                   const LocationContext *parent,
 329                                                   const BlockDecl *BD,
 330                                                   const void *ContextData) {
 331   llvm::FoldingSetNodeID ID;
 332   BlockInvocationContext::Profile(ID, ctx, parent, BD, ContextData);
 333   void *InsertPos;
 334   BlockInvocationContext *L =
 335     cast_or_null<BlockInvocationContext>(Contexts.FindNodeOrInsertPos(ID,
 336                                                                     InsertPos));
 337   if (!L) {
 338     L = new BlockInvocationContext(ctx, parent, BD, ContextData);
 339     Contexts.InsertNode(L, InsertPos);
 340   }
 341   return L;
 342 }
 343
 344 //===----------------------------------------------------------------------===//
 345 // LocationContext methods.
 346 //===----------------------------------------------------------------------===//
 347
 348 const StackFrameContext *LocationContext::getCurrentStackFrame() const {
 349   const LocationContext *LC = this;
 350   while (LC) {
 351     if (const StackFrameContext *SFC = dyn_cast<StackFrameContext>(LC))
 352       return SFC;
 353     LC = LC->getParent();
 354   }
 355   return NULL;
 356 }
 357
 358 bool LocationContext::inTopFrame() const {
 359   return getCurrentStackFrame()->inTopFrame();
 360 }
 361
 362 bool LocationContext::isParentOf(const LocationContext *LC) const {
 363   do {
 364     const LocationContext *Parent = LC->getParent();
 365     if (Parent == this)
 366       return true;
 367     else
 368       LC = Parent;
 369   } while (LC);
 370
 371   return false;
 372 }
 373
 374 //===----------------------------------------------------------------------===//
 375 // Lazily generated map to query the external variables referenced by a Block.
 376 //===----------------------------------------------------------------------===//
 377
 378 namespace {
 379 class FindBlockDeclRefExprsVals : public StmtVisitor<FindBlockDeclRefExprsVals>{
 380   BumpVector<const VarDecl*> &BEVals;
 381   BumpVectorContext &BC;
 382   llvm::SmallPtrSet<const VarDecl*, 4> Visited;
 383   llvm::SmallPtrSet<const DeclContext*, 4> IgnoredContexts;
 384 public:
 385   FindBlockDeclRefExprsVals(BumpVector<const VarDecl*> &bevals,
 386                             BumpVectorContext &bc)
 387   : BEVals(bevals), BC(bc) {}
 388
 389   bool IsTrackedDecl(const VarDecl *VD) {
 390     const DeclContext *DC = VD->getDeclContext();
 391     return IgnoredContexts.count(DC) == 0;
 392   }
 393
 394   void VisitStmt(Stmt *S) {
 395     for (Stmt::child_range I = S->children(); I; ++I)
 396       if (Stmt *child = *I)
 397         Visit(child);
 398   }
 399
 400   void VisitDeclRefExpr(DeclRefExpr *DR) {
 401     // Non-local variables are also directly modified.
 402     if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) {
 403       if (!VD->hasLocalStorage()) {
 404         if (Visited.insert(VD))
 405           BEVals.push_back(VD, BC);
 406       } else if (DR->refersToEnclosingLocal()) {
 407         if (Visited.insert(VD) && IsTrackedDecl(VD))
 408           BEVals.push_back(VD, BC);
 409       }
 410     }
 411   }
 412
 413   void VisitBlockExpr(BlockExpr *BR) {
 414     // Blocks containing blocks can transitively capture more variables.
 415     IgnoredContexts.insert(BR->getBlockDecl());
 416     Visit(BR->getBlockDecl()->getBody());
 417   }
 418
 419   void VisitPseudoObjectExpr(PseudoObjectExpr *PE) {
 420     for (PseudoObjectExpr::semantics_iterator it = PE->semantics_begin(),
 421          et = PE->semantics_end(); it != et; ++it) {
 422       Expr *Semantic = *it;
 423       if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic))
 424         Semantic = OVE->getSourceExpr();
 425       Visit(Semantic);
 426     }
 427   }
 428 };
 429 } // end anonymous namespace
 430
 431 typedef BumpVector<const VarDecl*> DeclVec;
 432
 433 static DeclVec* LazyInitializeReferencedDecls(const BlockDecl *BD,
 434                                               void *&Vec,
 435                                               llvm::BumpPtrAllocator &A) {
 436   if (Vec)
 437     return (DeclVec*) Vec;
 438
 439   BumpVectorContext BC(A);
 440   DeclVec *BV = (DeclVec*) A.Allocate<DeclVec>();
 441   new (BV) DeclVec(BC, 10);
 442
 443   // Find the referenced variables.
 444   FindBlockDeclRefExprsVals F(*BV, BC);
 445   F.Visit(BD->getBody());
 446
 447   Vec = BV;
 448   return BV;
 449 }
 450
 451 std::pair<AnalysisDeclContext::referenced_decls_iterator,
 452           AnalysisDeclContext::referenced_decls_iterator>
 453 AnalysisDeclContext::getReferencedBlockVars(const BlockDecl *BD) {
 454   if (!ReferencedBlockVars)
 455     ReferencedBlockVars = new llvm::DenseMap<const BlockDecl*,void*>();
 456
 457   DeclVec *V = LazyInitializeReferencedDecls(BD, (*ReferencedBlockVars)[BD], A);
 458   return std::make_pair(V->begin(), V->end());
 459 }
 460
 461 ManagedAnalysis *&AnalysisDeclContext::getAnalysisImpl(const void *tag) {
 462   if (!ManagedAnalyses)
 463     ManagedAnalyses = new ManagedAnalysisMap();
 464   ManagedAnalysisMap *M = (ManagedAnalysisMap*) ManagedAnalyses;
 465   return (*M)[tag];
 466 }
 467
 468 //===----------------------------------------------------------------------===//
 469 // Cleanup.
 470 //===----------------------------------------------------------------------===//
 471
 472 ManagedAnalysis::~ManagedAnalysis() {}
 473
 474 AnalysisDeclContext::~AnalysisDeclContext() {
 475   delete forcedBlkExprs;
 476   delete ReferencedBlockVars;
 477   // Release the managed analyses.
 478   if (ManagedAnalyses) {
 479     ManagedAnalysisMap *M = (ManagedAnalysisMap*) ManagedAnalyses;
 480     for (ManagedAnalysisMap::iterator I = M->begin(), E = M->end(); I!=E; ++I)
 481       delete I->second;
 482     delete M;
 483   }
 484 }
 485
 486 AnalysisDeclContextManager::~AnalysisDeclContextManager() {
 487   for (ContextMap::iterator I = Contexts.begin(), E = Contexts.end(); I!=E; ++I)
 488     delete I->second;
 489 }
 490
 491 LocationContext::~LocationContext() {}
 492
 493 LocationContextManager::~LocationContextManager() {
 494   clear();
 495 }
 496
 497 void LocationContextManager::clear() {
 498   for (llvm::FoldingSet<LocationContext>::iterator I = Contexts.begin(),
 499        E = Contexts.end(); I != E; ) {
 500     LocationContext *LC = &*I;
 501     ++I;
 502     delete LC;
 503   }
 504
 505   Contexts.clear();
 506 }
 507