AnalysisDeclContext.cpp revision fadcd5d5bbe1bfc1c6b8d819cc2242f780a49fec 
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
34using namespace clang;
35
36typedef llvm::DenseMap<const void *, ManagedAnalysis *> ManagedAnalysisMap;
37
38AnalysisDeclContext::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
53AnalysisDeclContext::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
66AnalysisDeclContextManager::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
79void AnalysisDeclContextManager::clear() {
80  for (ContextMap::iterator I = Contexts.begin(), E = Contexts.end(); I!=E; ++I)
81    delete I->second;
82  Contexts.clear();
83}
84
85static BodyFarm &getBodyFarm(ASTContext &C) {
86  static BodyFarm *BF = new BodyFarm(C);
87  return *BF;
88}
89
90Stmt *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
108const 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
124void 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
133const CFGBlock *
134AnalysisDeclContext::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
144CFG *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
158CFG *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
171CFGStmtMap *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
183CFGReverseBlockReachabilityAnalysis *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
195void AnalysisDeclContext::dumpCFG(bool ShowColors) {
196    getCFG()->dump(getASTContext().getLangOpts(), ShowColors);
197}
198
199ParentMap &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
213PseudoConstantAnalysis *AnalysisDeclContext::getPseudoConstantAnalysis() {
214  if (!PCA)
215    PCA.reset(new PseudoConstantAnalysis(getBody()));
216  return PCA.get();
217}
218
219AnalysisDeclContext *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
233const StackFrameContext *
234AnalysisDeclContext::getStackFrame(LocationContext const *Parent, const Stmt *S,
235                               const CFGBlock *Blk, unsigned Idx) {
236  return getLocationContextManager().getStackFrame(this, Parent, S, Blk, Idx);
237}
238
239const BlockInvocationContext *
240AnalysisDeclContext::getBlockInvocationContext(const LocationContext *parent,
241                                               const clang::BlockDecl *BD,
242                                               const void *ContextData) {
243  return getLocationContextManager().getBlockInvocationContext(this, parent,
244                                                               BD, ContextData);
245}
246
247LocationContextManager & AnalysisDeclContext::getLocationContextManager() {
248  assert(Manager &&
249         "Cannot create LocationContexts without an AnalysisDeclContextManager!");
250  return Manager->getLocationContextManager();
251}
252
253//===----------------------------------------------------------------------===//
254// FoldingSet profiling.
255//===----------------------------------------------------------------------===//
256
257void 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
268void StackFrameContext::Profile(llvm::FoldingSetNodeID &ID) {
269  Profile(ID, getAnalysisDeclContext(), getParent(), CallSite, Block, Index);
270}
271
272void ScopeContext::Profile(llvm::FoldingSetNodeID &ID) {
273  Profile(ID, getAnalysisDeclContext(), getParent(), Enter);
274}
275
276void BlockInvocationContext::Profile(llvm::FoldingSetNodeID &ID) {
277  Profile(ID, getAnalysisDeclContext(), getParent(), BD, ContextData);
278}
279
280//===----------------------------------------------------------------------===//
281// LocationContext creation.
282//===----------------------------------------------------------------------===//
283
284template <typename LOC, typename DATA>
285const LOC*
286LocationContextManager::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
302const StackFrameContext*
303LocationContextManager::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
319const ScopeContext *
320LocationContextManager::getScope(AnalysisDeclContext *ctx,
321                                 const LocationContext *parent,
322                                 const Stmt *s) {
323  return getLocationContext<ScopeContext, Stmt>(ctx, parent, s);
324}
325
326const BlockInvocationContext *
327LocationContextManager::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
348const 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
358bool LocationContext::inTopFrame() const {
359  return getCurrentStackFrame()->inTopFrame();
360}
361
362bool 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
378namespace {
379class 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;
384public:
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
431typedef BumpVector<const VarDecl*> DeclVec;
432
433static 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
451std::pair<AnalysisDeclContext::referenced_decls_iterator,
452          AnalysisDeclContext::referenced_decls_iterator>
453AnalysisDeclContext::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
461ManagedAnalysis *&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
472ManagedAnalysis::~ManagedAnalysis() {}
473
474AnalysisDeclContext::~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
486AnalysisDeclContextManager::~AnalysisDeclContextManager() {
487  for (ContextMap::iterator I = Contexts.begin(), E = Contexts.end(); I!=E; ++I)
488    delete I->second;
489}
490
491LocationContext::~LocationContext() {}
492
493LocationContextManager::~LocationContextManager() {
494  clear();
495}
496
497void 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
508