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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 using namespace clang;
33 
34 typedef llvm::DenseMap<const void *, ManagedAnalysis *> ManagedAnalysisMap;
35 
AnalysisDeclContext(AnalysisDeclContextManager * Mgr,const Decl * d,const CFG::BuildOptions & buildOptions)36 AnalysisDeclContext::AnalysisDeclContext(AnalysisDeclContextManager *Mgr,
37                                  const Decl *d,
38                                  const CFG::BuildOptions &buildOptions)
39   : Manager(Mgr),
40     D(d),
41     cfgBuildOptions(buildOptions),
42     forcedBlkExprs(0),
43     builtCFG(false),
44     builtCompleteCFG(false),
45     ReferencedBlockVars(0),
46     ManagedAnalyses(0)
47 {
48   cfgBuildOptions.forcedBlkExprs = &forcedBlkExprs;
49 }
50 
AnalysisDeclContext(AnalysisDeclContextManager * Mgr,const Decl * d)51 AnalysisDeclContext::AnalysisDeclContext(AnalysisDeclContextManager *Mgr,
52                                  const Decl *d)
53 : Manager(Mgr),
54   D(d),
55   forcedBlkExprs(0),
56   builtCFG(false),
57   builtCompleteCFG(false),
58   ReferencedBlockVars(0),
59   ManagedAnalyses(0)
60 {
61   cfgBuildOptions.forcedBlkExprs = &forcedBlkExprs;
62 }
63 
AnalysisDeclContextManager(bool useUnoptimizedCFG,bool addImplicitDtors,bool addInitializers,bool addTemporaryDtors)64 AnalysisDeclContextManager::AnalysisDeclContextManager(bool useUnoptimizedCFG,
65                                                        bool addImplicitDtors,
66                                                        bool addInitializers,
67                                                        bool addTemporaryDtors) {
68   cfgBuildOptions.PruneTriviallyFalseEdges = !useUnoptimizedCFG;
69   cfgBuildOptions.AddImplicitDtors = addImplicitDtors;
70   cfgBuildOptions.AddInitializers = addInitializers;
71   cfgBuildOptions.AddTemporaryDtors = addTemporaryDtors;
72 }
73 
clear()74 void AnalysisDeclContextManager::clear() {
75   for (ContextMap::iterator I = Contexts.begin(), E = Contexts.end(); I!=E; ++I)
76     delete I->second;
77   Contexts.clear();
78 }
79 
getBody() const80 Stmt *AnalysisDeclContext::getBody() const {
81   if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
82     return FD->getBody();
83   else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D))
84     return MD->getBody();
85   else if (const BlockDecl *BD = dyn_cast<BlockDecl>(D))
86     return BD->getBody();
87   else if (const FunctionTemplateDecl *FunTmpl
88            = dyn_cast_or_null<FunctionTemplateDecl>(D))
89     return FunTmpl->getTemplatedDecl()->getBody();
90 
91   llvm_unreachable("unknown code decl");
92 }
93 
getSelfDecl() const94 const ImplicitParamDecl *AnalysisDeclContext::getSelfDecl() const {
95   if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D))
96     return MD->getSelfDecl();
97   if (const BlockDecl *BD = dyn_cast<BlockDecl>(D)) {
98     // See if 'self' was captured by the block.
99     for (BlockDecl::capture_const_iterator it = BD->capture_begin(),
100          et = BD->capture_end(); it != et; ++it) {
101       const VarDecl *VD = it->getVariable();
102       if (VD->getName() == "self")
103         return dyn_cast<ImplicitParamDecl>(VD);
104     }
105   }
106 
107   return NULL;
108 }
109 
registerForcedBlockExpression(const Stmt * stmt)110 void AnalysisDeclContext::registerForcedBlockExpression(const Stmt *stmt) {
111   if (!forcedBlkExprs)
112     forcedBlkExprs = new CFG::BuildOptions::ForcedBlkExprs();
113   // Default construct an entry for 'stmt'.
114   if (const Expr *e = dyn_cast<Expr>(stmt))
115     stmt = e->IgnoreParens();
116   (void) (*forcedBlkExprs)[stmt];
117 }
118 
119 const CFGBlock *
getBlockForRegisteredExpression(const Stmt * stmt)120 AnalysisDeclContext::getBlockForRegisteredExpression(const Stmt *stmt) {
121   assert(forcedBlkExprs);
122   if (const Expr *e = dyn_cast<Expr>(stmt))
123     stmt = e->IgnoreParens();
124   CFG::BuildOptions::ForcedBlkExprs::const_iterator itr =
125     forcedBlkExprs->find(stmt);
126   assert(itr != forcedBlkExprs->end());
127   return itr->second;
128 }
129 
getCFG()130 CFG *AnalysisDeclContext::getCFG() {
131   if (!cfgBuildOptions.PruneTriviallyFalseEdges)
132     return getUnoptimizedCFG();
133 
134   if (!builtCFG) {
135     cfg.reset(CFG::buildCFG(D, getBody(),
136                             &D->getASTContext(), cfgBuildOptions));
137     // Even when the cfg is not successfully built, we don't
138     // want to try building it again.
139     builtCFG = true;
140   }
141   return cfg.get();
142 }
143 
getUnoptimizedCFG()144 CFG *AnalysisDeclContext::getUnoptimizedCFG() {
145   if (!builtCompleteCFG) {
146     SaveAndRestore<bool> NotPrune(cfgBuildOptions.PruneTriviallyFalseEdges,
147                                   false);
148     completeCFG.reset(CFG::buildCFG(D, getBody(), &D->getASTContext(),
149                                     cfgBuildOptions));
150     // Even when the cfg is not successfully built, we don't
151     // want to try building it again.
152     builtCompleteCFG = true;
153   }
154   return completeCFG.get();
155 }
156 
getCFGStmtMap()157 CFGStmtMap *AnalysisDeclContext::getCFGStmtMap() {
158   if (cfgStmtMap)
159     return cfgStmtMap.get();
160 
161   if (CFG *c = getCFG()) {
162     cfgStmtMap.reset(CFGStmtMap::Build(c, &getParentMap()));
163     return cfgStmtMap.get();
164   }
165 
166   return 0;
167 }
168 
getCFGReachablityAnalysis()169 CFGReverseBlockReachabilityAnalysis *AnalysisDeclContext::getCFGReachablityAnalysis() {
170   if (CFA)
171     return CFA.get();
172 
173   if (CFG *c = getCFG()) {
174     CFA.reset(new CFGReverseBlockReachabilityAnalysis(*c));
175     return CFA.get();
176   }
177 
178   return 0;
179 }
180 
dumpCFG(bool ShowColors)181 void AnalysisDeclContext::dumpCFG(bool ShowColors) {
182     getCFG()->dump(getASTContext().getLangOpts(), ShowColors);
183 }
184 
getParentMap()185 ParentMap &AnalysisDeclContext::getParentMap() {
186   if (!PM) {
187     PM.reset(new ParentMap(getBody()));
188     if (const CXXConstructorDecl *C = dyn_cast<CXXConstructorDecl>(getDecl())) {
189       for (CXXConstructorDecl::init_const_iterator I = C->init_begin(),
190                                                    E = C->init_end();
191            I != E; ++I) {
192         PM->addStmt((*I)->getInit());
193       }
194     }
195   }
196   return *PM;
197 }
198 
getPseudoConstantAnalysis()199 PseudoConstantAnalysis *AnalysisDeclContext::getPseudoConstantAnalysis() {
200   if (!PCA)
201     PCA.reset(new PseudoConstantAnalysis(getBody()));
202   return PCA.get();
203 }
204 
getContext(const Decl * D)205 AnalysisDeclContext *AnalysisDeclContextManager::getContext(const Decl *D) {
206   AnalysisDeclContext *&AC = Contexts[D];
207   if (!AC)
208     AC = new AnalysisDeclContext(this, D, cfgBuildOptions);
209   return AC;
210 }
211 
212 const StackFrameContext *
getStackFrame(LocationContext const * Parent,const Stmt * S,const CFGBlock * Blk,unsigned Idx)213 AnalysisDeclContext::getStackFrame(LocationContext const *Parent, const Stmt *S,
214                                const CFGBlock *Blk, unsigned Idx) {
215   return getLocationContextManager().getStackFrame(this, Parent, S, Blk, Idx);
216 }
217 
218 const BlockInvocationContext *
getBlockInvocationContext(const LocationContext * parent,const clang::BlockDecl * BD,const void * ContextData)219 AnalysisDeclContext::getBlockInvocationContext(const LocationContext *parent,
220                                                const clang::BlockDecl *BD,
221                                                const void *ContextData) {
222   return getLocationContextManager().getBlockInvocationContext(this, parent,
223                                                                BD, ContextData);
224 }
225 
getLocationContextManager()226 LocationContextManager & AnalysisDeclContext::getLocationContextManager() {
227   assert(Manager &&
228          "Cannot create LocationContexts without an AnalysisDeclContextManager!");
229   return Manager->getLocationContextManager();
230 }
231 
232 //===----------------------------------------------------------------------===//
233 // FoldingSet profiling.
234 //===----------------------------------------------------------------------===//
235 
ProfileCommon(llvm::FoldingSetNodeID & ID,ContextKind ck,AnalysisDeclContext * ctx,const LocationContext * parent,const void * data)236 void LocationContext::ProfileCommon(llvm::FoldingSetNodeID &ID,
237                                     ContextKind ck,
238                                     AnalysisDeclContext *ctx,
239                                     const LocationContext *parent,
240                                     const void *data) {
241   ID.AddInteger(ck);
242   ID.AddPointer(ctx);
243   ID.AddPointer(parent);
244   ID.AddPointer(data);
245 }
246 
Profile(llvm::FoldingSetNodeID & ID)247 void StackFrameContext::Profile(llvm::FoldingSetNodeID &ID) {
248   Profile(ID, getAnalysisDeclContext(), getParent(), CallSite, Block, Index);
249 }
250 
Profile(llvm::FoldingSetNodeID & ID)251 void ScopeContext::Profile(llvm::FoldingSetNodeID &ID) {
252   Profile(ID, getAnalysisDeclContext(), getParent(), Enter);
253 }
254 
Profile(llvm::FoldingSetNodeID & ID)255 void BlockInvocationContext::Profile(llvm::FoldingSetNodeID &ID) {
256   Profile(ID, getAnalysisDeclContext(), getParent(), BD, ContextData);
257 }
258 
259 //===----------------------------------------------------------------------===//
260 // LocationContext creation.
261 //===----------------------------------------------------------------------===//
262 
263 template <typename LOC, typename DATA>
264 const LOC*
getLocationContext(AnalysisDeclContext * ctx,const LocationContext * parent,const DATA * d)265 LocationContextManager::getLocationContext(AnalysisDeclContext *ctx,
266                                            const LocationContext *parent,
267                                            const DATA *d) {
268   llvm::FoldingSetNodeID ID;
269   LOC::Profile(ID, ctx, parent, d);
270   void *InsertPos;
271 
272   LOC *L = cast_or_null<LOC>(Contexts.FindNodeOrInsertPos(ID, InsertPos));
273 
274   if (!L) {
275     L = new LOC(ctx, parent, d);
276     Contexts.InsertNode(L, InsertPos);
277   }
278   return L;
279 }
280 
281 const StackFrameContext*
getStackFrame(AnalysisDeclContext * ctx,const LocationContext * parent,const Stmt * s,const CFGBlock * blk,unsigned idx)282 LocationContextManager::getStackFrame(AnalysisDeclContext *ctx,
283                                       const LocationContext *parent,
284                                       const Stmt *s,
285                                       const CFGBlock *blk, unsigned idx) {
286   llvm::FoldingSetNodeID ID;
287   StackFrameContext::Profile(ID, ctx, parent, s, blk, idx);
288   void *InsertPos;
289   StackFrameContext *L =
290    cast_or_null<StackFrameContext>(Contexts.FindNodeOrInsertPos(ID, InsertPos));
291   if (!L) {
292     L = new StackFrameContext(ctx, parent, s, blk, idx);
293     Contexts.InsertNode(L, InsertPos);
294   }
295   return L;
296 }
297 
298 const ScopeContext *
getScope(AnalysisDeclContext * ctx,const LocationContext * parent,const Stmt * s)299 LocationContextManager::getScope(AnalysisDeclContext *ctx,
300                                  const LocationContext *parent,
301                                  const Stmt *s) {
302   return getLocationContext<ScopeContext, Stmt>(ctx, parent, s);
303 }
304 
305 const BlockInvocationContext *
getBlockInvocationContext(AnalysisDeclContext * ctx,const LocationContext * parent,const BlockDecl * BD,const void * ContextData)306 LocationContextManager::getBlockInvocationContext(AnalysisDeclContext *ctx,
307                                                   const LocationContext *parent,
308                                                   const BlockDecl *BD,
309                                                   const void *ContextData) {
310   llvm::FoldingSetNodeID ID;
311   BlockInvocationContext::Profile(ID, ctx, parent, BD, ContextData);
312   void *InsertPos;
313   BlockInvocationContext *L =
314     cast_or_null<BlockInvocationContext>(Contexts.FindNodeOrInsertPos(ID,
315                                                                     InsertPos));
316   if (!L) {
317     L = new BlockInvocationContext(ctx, parent, BD, ContextData);
318     Contexts.InsertNode(L, InsertPos);
319   }
320   return L;
321 }
322 
323 //===----------------------------------------------------------------------===//
324 // LocationContext methods.
325 //===----------------------------------------------------------------------===//
326 
getCurrentStackFrame() const327 const StackFrameContext *LocationContext::getCurrentStackFrame() const {
328   const LocationContext *LC = this;
329   while (LC) {
330     if (const StackFrameContext *SFC = dyn_cast<StackFrameContext>(LC))
331       return SFC;
332     LC = LC->getParent();
333   }
334   return NULL;
335 }
336 
isParentOf(const LocationContext * LC) const337 bool LocationContext::isParentOf(const LocationContext *LC) const {
338   do {
339     const LocationContext *Parent = LC->getParent();
340     if (Parent == this)
341       return true;
342     else
343       LC = Parent;
344   } while (LC);
345 
346   return false;
347 }
348 
349 //===----------------------------------------------------------------------===//
350 // Lazily generated map to query the external variables referenced by a Block.
351 //===----------------------------------------------------------------------===//
352 
353 namespace {
354 class FindBlockDeclRefExprsVals : public StmtVisitor<FindBlockDeclRefExprsVals>{
355   BumpVector<const VarDecl*> &BEVals;
356   BumpVectorContext &BC;
357   llvm::SmallPtrSet<const VarDecl*, 4> Visited;
358   llvm::SmallPtrSet<const DeclContext*, 4> IgnoredContexts;
359 public:
FindBlockDeclRefExprsVals(BumpVector<const VarDecl * > & bevals,BumpVectorContext & bc)360   FindBlockDeclRefExprsVals(BumpVector<const VarDecl*> &bevals,
361                             BumpVectorContext &bc)
362   : BEVals(bevals), BC(bc) {}
363 
IsTrackedDecl(const VarDecl * VD)364   bool IsTrackedDecl(const VarDecl *VD) {
365     const DeclContext *DC = VD->getDeclContext();
366     return IgnoredContexts.count(DC) == 0;
367   }
368 
VisitStmt(Stmt * S)369   void VisitStmt(Stmt *S) {
370     for (Stmt::child_range I = S->children(); I; ++I)
371       if (Stmt *child = *I)
372         Visit(child);
373   }
374 
VisitDeclRefExpr(DeclRefExpr * DR)375   void VisitDeclRefExpr(DeclRefExpr *DR) {
376     // Non-local variables are also directly modified.
377     if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) {
378       if (!VD->hasLocalStorage()) {
379         if (Visited.insert(VD))
380           BEVals.push_back(VD, BC);
381       } else if (DR->refersToEnclosingLocal()) {
382         if (Visited.insert(VD) && IsTrackedDecl(VD))
383           BEVals.push_back(VD, BC);
384       }
385     }
386   }
387 
VisitBlockExpr(BlockExpr * BR)388   void VisitBlockExpr(BlockExpr *BR) {
389     // Blocks containing blocks can transitively capture more variables.
390     IgnoredContexts.insert(BR->getBlockDecl());
391     Visit(BR->getBlockDecl()->getBody());
392   }
393 
VisitPseudoObjectExpr(PseudoObjectExpr * PE)394   void VisitPseudoObjectExpr(PseudoObjectExpr *PE) {
395     for (PseudoObjectExpr::semantics_iterator it = PE->semantics_begin(),
396          et = PE->semantics_end(); it != et; ++it) {
397       Expr *Semantic = *it;
398       if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic))
399         Semantic = OVE->getSourceExpr();
400       Visit(Semantic);
401     }
402   }
403 };
404 } // end anonymous namespace
405 
406 typedef BumpVector<const VarDecl*> DeclVec;
407 
LazyInitializeReferencedDecls(const BlockDecl * BD,void * & Vec,llvm::BumpPtrAllocator & A)408 static DeclVec* LazyInitializeReferencedDecls(const BlockDecl *BD,
409                                               void *&Vec,
410                                               llvm::BumpPtrAllocator &A) {
411   if (Vec)
412     return (DeclVec*) Vec;
413 
414   BumpVectorContext BC(A);
415   DeclVec *BV = (DeclVec*) A.Allocate<DeclVec>();
416   new (BV) DeclVec(BC, 10);
417 
418   // Find the referenced variables.
419   FindBlockDeclRefExprsVals F(*BV, BC);
420   F.Visit(BD->getBody());
421 
422   Vec = BV;
423   return BV;
424 }
425 
426 std::pair<AnalysisDeclContext::referenced_decls_iterator,
427           AnalysisDeclContext::referenced_decls_iterator>
getReferencedBlockVars(const BlockDecl * BD)428 AnalysisDeclContext::getReferencedBlockVars(const BlockDecl *BD) {
429   if (!ReferencedBlockVars)
430     ReferencedBlockVars = new llvm::DenseMap<const BlockDecl*,void*>();
431 
432   DeclVec *V = LazyInitializeReferencedDecls(BD, (*ReferencedBlockVars)[BD], A);
433   return std::make_pair(V->begin(), V->end());
434 }
435 
getAnalysisImpl(const void * tag)436 ManagedAnalysis *&AnalysisDeclContext::getAnalysisImpl(const void *tag) {
437   if (!ManagedAnalyses)
438     ManagedAnalyses = new ManagedAnalysisMap();
439   ManagedAnalysisMap *M = (ManagedAnalysisMap*) ManagedAnalyses;
440   return (*M)[tag];
441 }
442 
443 //===----------------------------------------------------------------------===//
444 // Cleanup.
445 //===----------------------------------------------------------------------===//
446 
~ManagedAnalysis()447 ManagedAnalysis::~ManagedAnalysis() {}
448 
~AnalysisDeclContext()449 AnalysisDeclContext::~AnalysisDeclContext() {
450   delete forcedBlkExprs;
451   delete ReferencedBlockVars;
452   // Release the managed analyses.
453   if (ManagedAnalyses) {
454     ManagedAnalysisMap *M = (ManagedAnalysisMap*) ManagedAnalyses;
455     for (ManagedAnalysisMap::iterator I = M->begin(), E = M->end(); I!=E; ++I)
456       delete I->second;
457     delete M;
458   }
459 }
460 
~AnalysisDeclContextManager()461 AnalysisDeclContextManager::~AnalysisDeclContextManager() {
462   for (ContextMap::iterator I = Contexts.begin(), E = Contexts.end(); I!=E; ++I)
463     delete I->second;
464 }
465 
~LocationContext()466 LocationContext::~LocationContext() {}
467 
~LocationContextManager()468 LocationContextManager::~LocationContextManager() {
469   clear();
470 }
471 
clear()472 void LocationContextManager::clear() {
473   for (llvm::FoldingSet<LocationContext>::iterator I = Contexts.begin(),
474        E = Contexts.end(); I != E; ) {
475     LocationContext *LC = &*I;
476     ++I;
477     delete LC;
478   }
479 
480   Contexts.clear();
481 }
482 
483