AnalysisDeclContext.cpp revision 453cb859a3c8dcafe79ae840dfc35ff8eae1b4b3 
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
33using namespace clang;
34
35typedef llvm::DenseMap<const void *, ManagedAnalysis *> ManagedAnalysisMap;
36
37AnalysisDeclContext::AnalysisDeclContext(AnalysisDeclContextManager *Mgr,
38                                         const Decl *d,
39                                         const CFG::BuildOptions &buildOptions)
40  : Manager(Mgr),
41    D(d),
42    cfgBuildOptions(buildOptions),
43    forcedBlkExprs(0),
44    builtCFG(false),
45    builtCompleteCFG(false),
46    ReferencedBlockVars(0),
47    ManagedAnalyses(0)
48{
49  cfgBuildOptions.forcedBlkExprs = &forcedBlkExprs;
50}
51
52AnalysisDeclContext::AnalysisDeclContext(AnalysisDeclContextManager *Mgr,
53                                         const Decl *d)
54: Manager(Mgr),
55  D(d),
56  forcedBlkExprs(0),
57  builtCFG(false),
58  builtCompleteCFG(false),
59  ReferencedBlockVars(0),
60  ManagedAnalyses(0)
61{
62  cfgBuildOptions.forcedBlkExprs = &forcedBlkExprs;
63}
64
65AnalysisDeclContextManager::AnalysisDeclContextManager(bool useUnoptimizedCFG,
66                                                       bool addImplicitDtors,
67                                                       bool addInitializers,
68                                                       bool addTemporaryDtors,
69                                                       bool synthesizeBodies)
70  : SynthesizeBodies(synthesizeBodies)
71{
72  cfgBuildOptions.PruneTriviallyFalseEdges = !useUnoptimizedCFG;
73  cfgBuildOptions.AddImplicitDtors = addImplicitDtors;
74  cfgBuildOptions.AddInitializers = addInitializers;
75  cfgBuildOptions.AddTemporaryDtors = addTemporaryDtors;
76}
77
78void AnalysisDeclContextManager::clear() {
79  for (ContextMap::iterator I = Contexts.begin(), E = Contexts.end(); I!=E; ++I)
80    delete I->second;
81  Contexts.clear();
82}
83
84static BodyFarm &getBodyFarm(ASTContext &C) {
85  static BodyFarm *BF = new BodyFarm(C);
86  return *BF;
87}
88
89Stmt *AnalysisDeclContext::getBody(bool &IsAutosynthesized) const {
90  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
91    Stmt *Body = FD->getBody();
92    if (!Body && Manager && Manager->synthesizeBodies()) {
93      IsAutosynthesized = true;
94      return getBodyFarm(getASTContext()).getBody(FD);
95    }
96    return Body;
97  }
98  else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D))
99    return MD->getBody();
100  else if (const BlockDecl *BD = dyn_cast<BlockDecl>(D))
101    return BD->getBody();
102  else if (const FunctionTemplateDecl *FunTmpl
103           = dyn_cast_or_null<FunctionTemplateDecl>(D))
104    return FunTmpl->getTemplatedDecl()->getBody();
105
106  llvm_unreachable("unknown code decl");
107}
108
109Stmt *AnalysisDeclContext::getBody() const {
110  bool Tmp;
111  return getBody(Tmp);
112}
113
114bool AnalysisDeclContext::isBodyAutosynthesized() const {
115  bool Tmp;
116  getBody(Tmp);
117  return Tmp;
118}
119
120const ImplicitParamDecl *AnalysisDeclContext::getSelfDecl() const {
121  if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D))
122    return MD->getSelfDecl();
123  if (const BlockDecl *BD = dyn_cast<BlockDecl>(D)) {
124    // See if 'self' was captured by the block.
125    for (BlockDecl::capture_const_iterator it = BD->capture_begin(),
126         et = BD->capture_end(); it != et; ++it) {
127      const VarDecl *VD = it->getVariable();
128      if (VD->getName() == "self")
129        return dyn_cast<ImplicitParamDecl>(VD);
130    }
131  }
132
133  return NULL;
134}
135
136void AnalysisDeclContext::registerForcedBlockExpression(const Stmt *stmt) {
137  if (!forcedBlkExprs)
138    forcedBlkExprs = new CFG::BuildOptions::ForcedBlkExprs();
139  // Default construct an entry for 'stmt'.
140  if (const Expr *e = dyn_cast<Expr>(stmt))
141    stmt = e->IgnoreParens();
142  (void) (*forcedBlkExprs)[stmt];
143}
144
145const CFGBlock *
146AnalysisDeclContext::getBlockForRegisteredExpression(const Stmt *stmt) {
147  assert(forcedBlkExprs);
148  if (const Expr *e = dyn_cast<Expr>(stmt))
149    stmt = e->IgnoreParens();
150  CFG::BuildOptions::ForcedBlkExprs::const_iterator itr =
151    forcedBlkExprs->find(stmt);
152  assert(itr != forcedBlkExprs->end());
153  return itr->second;
154}
155
156CFG *AnalysisDeclContext::getCFG() {
157  if (!cfgBuildOptions.PruneTriviallyFalseEdges)
158    return getUnoptimizedCFG();
159
160  if (!builtCFG) {
161    cfg.reset(CFG::buildCFG(D, getBody(),
162                            &D->getASTContext(), cfgBuildOptions));
163    // Even when the cfg is not successfully built, we don't
164    // want to try building it again.
165    builtCFG = true;
166  }
167  return cfg.get();
168}
169
170CFG *AnalysisDeclContext::getUnoptimizedCFG() {
171  if (!builtCompleteCFG) {
172    SaveAndRestore<bool> NotPrune(cfgBuildOptions.PruneTriviallyFalseEdges,
173                                  false);
174    completeCFG.reset(CFG::buildCFG(D, getBody(), &D->getASTContext(),
175                                    cfgBuildOptions));
176    // Even when the cfg is not successfully built, we don't
177    // want to try building it again.
178    builtCompleteCFG = true;
179  }
180  return completeCFG.get();
181}
182
183CFGStmtMap *AnalysisDeclContext::getCFGStmtMap() {
184  if (cfgStmtMap)
185    return cfgStmtMap.get();
186
187  if (CFG *c = getCFG()) {
188    cfgStmtMap.reset(CFGStmtMap::Build(c, &getParentMap()));
189    return cfgStmtMap.get();
190  }
191
192  return 0;
193}
194
195CFGReverseBlockReachabilityAnalysis *AnalysisDeclContext::getCFGReachablityAnalysis() {
196  if (CFA)
197    return CFA.get();
198
199  if (CFG *c = getCFG()) {
200    CFA.reset(new CFGReverseBlockReachabilityAnalysis(*c));
201    return CFA.get();
202  }
203
204  return 0;
205}
206
207void AnalysisDeclContext::dumpCFG(bool ShowColors) {
208    getCFG()->dump(getASTContext().getLangOpts(), ShowColors);
209}
210
211ParentMap &AnalysisDeclContext::getParentMap() {
212  if (!PM) {
213    PM.reset(new ParentMap(getBody()));
214    if (const CXXConstructorDecl *C = dyn_cast<CXXConstructorDecl>(getDecl())) {
215      for (CXXConstructorDecl::init_const_iterator I = C->init_begin(),
216                                                   E = C->init_end();
217           I != E; ++I) {
218        PM->addStmt((*I)->getInit());
219      }
220    }
221  }
222  return *PM;
223}
224
225PseudoConstantAnalysis *AnalysisDeclContext::getPseudoConstantAnalysis() {
226  if (!PCA)
227    PCA.reset(new PseudoConstantAnalysis(getBody()));
228  return PCA.get();
229}
230
231AnalysisDeclContext *AnalysisDeclContextManager::getContext(const Decl *D) {
232  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
233    // Calling 'hasBody' replaces 'FD' in place with the FunctionDecl
234    // that has the body.
235    FD->hasBody(FD);
236    D = FD;
237  }
238
239  AnalysisDeclContext *&AC = Contexts[D];
240  if (!AC)
241    AC = new AnalysisDeclContext(this, D, cfgBuildOptions);
242  return AC;
243}
244
245const StackFrameContext *
246AnalysisDeclContext::getStackFrame(LocationContext const *Parent, const Stmt *S,
247                               const CFGBlock *Blk, unsigned Idx) {
248  return getLocationContextManager().getStackFrame(this, Parent, S, Blk, Idx);
249}
250
251const BlockInvocationContext *
252AnalysisDeclContext::getBlockInvocationContext(const LocationContext *parent,
253                                               const clang::BlockDecl *BD,
254                                               const void *ContextData) {
255  return getLocationContextManager().getBlockInvocationContext(this, parent,
256                                                               BD, ContextData);
257}
258
259LocationContextManager & AnalysisDeclContext::getLocationContextManager() {
260  assert(Manager &&
261         "Cannot create LocationContexts without an AnalysisDeclContextManager!");
262  return Manager->getLocationContextManager();
263}
264
265//===----------------------------------------------------------------------===//
266// FoldingSet profiling.
267//===----------------------------------------------------------------------===//
268
269void LocationContext::ProfileCommon(llvm::FoldingSetNodeID &ID,
270                                    ContextKind ck,
271                                    AnalysisDeclContext *ctx,
272                                    const LocationContext *parent,
273                                    const void *data) {
274  ID.AddInteger(ck);
275  ID.AddPointer(ctx);
276  ID.AddPointer(parent);
277  ID.AddPointer(data);
278}
279
280void StackFrameContext::Profile(llvm::FoldingSetNodeID &ID) {
281  Profile(ID, getAnalysisDeclContext(), getParent(), CallSite, Block, Index);
282}
283
284void ScopeContext::Profile(llvm::FoldingSetNodeID &ID) {
285  Profile(ID, getAnalysisDeclContext(), getParent(), Enter);
286}
287
288void BlockInvocationContext::Profile(llvm::FoldingSetNodeID &ID) {
289  Profile(ID, getAnalysisDeclContext(), getParent(), BD, ContextData);
290}
291
292//===----------------------------------------------------------------------===//
293// LocationContext creation.
294//===----------------------------------------------------------------------===//
295
296template <typename LOC, typename DATA>
297const LOC*
298LocationContextManager::getLocationContext(AnalysisDeclContext *ctx,
299                                           const LocationContext *parent,
300                                           const DATA *d) {
301  llvm::FoldingSetNodeID ID;
302  LOC::Profile(ID, ctx, parent, d);
303  void *InsertPos;
304
305  LOC *L = cast_or_null<LOC>(Contexts.FindNodeOrInsertPos(ID, InsertPos));
306
307  if (!L) {
308    L = new LOC(ctx, parent, d);
309    Contexts.InsertNode(L, InsertPos);
310  }
311  return L;
312}
313
314const StackFrameContext*
315LocationContextManager::getStackFrame(AnalysisDeclContext *ctx,
316                                      const LocationContext *parent,
317                                      const Stmt *s,
318                                      const CFGBlock *blk, unsigned idx) {
319  llvm::FoldingSetNodeID ID;
320  StackFrameContext::Profile(ID, ctx, parent, s, blk, idx);
321  void *InsertPos;
322  StackFrameContext *L =
323   cast_or_null<StackFrameContext>(Contexts.FindNodeOrInsertPos(ID, InsertPos));
324  if (!L) {
325    L = new StackFrameContext(ctx, parent, s, blk, idx);
326    Contexts.InsertNode(L, InsertPos);
327  }
328  return L;
329}
330
331const ScopeContext *
332LocationContextManager::getScope(AnalysisDeclContext *ctx,
333                                 const LocationContext *parent,
334                                 const Stmt *s) {
335  return getLocationContext<ScopeContext, Stmt>(ctx, parent, s);
336}
337
338const BlockInvocationContext *
339LocationContextManager::getBlockInvocationContext(AnalysisDeclContext *ctx,
340                                                  const LocationContext *parent,
341                                                  const BlockDecl *BD,
342                                                  const void *ContextData) {
343  llvm::FoldingSetNodeID ID;
344  BlockInvocationContext::Profile(ID, ctx, parent, BD, ContextData);
345  void *InsertPos;
346  BlockInvocationContext *L =
347    cast_or_null<BlockInvocationContext>(Contexts.FindNodeOrInsertPos(ID,
348                                                                    InsertPos));
349  if (!L) {
350    L = new BlockInvocationContext(ctx, parent, BD, ContextData);
351    Contexts.InsertNode(L, InsertPos);
352  }
353  return L;
354}
355
356//===----------------------------------------------------------------------===//
357// LocationContext methods.
358//===----------------------------------------------------------------------===//
359
360const StackFrameContext *LocationContext::getCurrentStackFrame() const {
361  const LocationContext *LC = this;
362  while (LC) {
363    if (const StackFrameContext *SFC = dyn_cast<StackFrameContext>(LC))
364      return SFC;
365    LC = LC->getParent();
366  }
367  return NULL;
368}
369
370bool LocationContext::inTopFrame() const {
371  return getCurrentStackFrame()->inTopFrame();
372}
373
374bool LocationContext::isParentOf(const LocationContext *LC) const {
375  do {
376    const LocationContext *Parent = LC->getParent();
377    if (Parent == this)
378      return true;
379    else
380      LC = Parent;
381  } while (LC);
382
383  return false;
384}
385
386//===----------------------------------------------------------------------===//
387// Lazily generated map to query the external variables referenced by a Block.
388//===----------------------------------------------------------------------===//
389
390namespace {
391class FindBlockDeclRefExprsVals : public StmtVisitor<FindBlockDeclRefExprsVals>{
392  BumpVector<const VarDecl*> &BEVals;
393  BumpVectorContext &BC;
394  llvm::SmallPtrSet<const VarDecl*, 4> Visited;
395  llvm::SmallPtrSet<const DeclContext*, 4> IgnoredContexts;
396public:
397  FindBlockDeclRefExprsVals(BumpVector<const VarDecl*> &bevals,
398                            BumpVectorContext &bc)
399  : BEVals(bevals), BC(bc) {}
400
401  bool IsTrackedDecl(const VarDecl *VD) {
402    const DeclContext *DC = VD->getDeclContext();
403    return IgnoredContexts.count(DC) == 0;
404  }
405
406  void VisitStmt(Stmt *S) {
407    for (Stmt::child_range I = S->children(); I; ++I)
408      if (Stmt *child = *I)
409        Visit(child);
410  }
411
412  void VisitDeclRefExpr(DeclRefExpr *DR) {
413    // Non-local variables are also directly modified.
414    if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) {
415      if (!VD->hasLocalStorage()) {
416        if (Visited.insert(VD))
417          BEVals.push_back(VD, BC);
418      }
419    }
420  }
421
422  void VisitBlockExpr(BlockExpr *BR) {
423    // Blocks containing blocks can transitively capture more variables.
424    IgnoredContexts.insert(BR->getBlockDecl());
425    Visit(BR->getBlockDecl()->getBody());
426  }
427
428  void VisitPseudoObjectExpr(PseudoObjectExpr *PE) {
429    for (PseudoObjectExpr::semantics_iterator it = PE->semantics_begin(),
430         et = PE->semantics_end(); it != et; ++it) {
431      Expr *Semantic = *it;
432      if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic))
433        Semantic = OVE->getSourceExpr();
434      Visit(Semantic);
435    }
436  }
437};
438} // end anonymous namespace
439
440typedef BumpVector<const VarDecl*> DeclVec;
441
442static DeclVec* LazyInitializeReferencedDecls(const BlockDecl *BD,
443                                              void *&Vec,
444                                              llvm::BumpPtrAllocator &A) {
445  if (Vec)
446    return (DeclVec*) Vec;
447
448  BumpVectorContext BC(A);
449  DeclVec *BV = (DeclVec*) A.Allocate<DeclVec>();
450  new (BV) DeclVec(BC, 10);
451
452  // Go through the capture list.
453  for (BlockDecl::capture_const_iterator CI = BD->capture_begin(),
454       CE = BD->capture_end(); CI != CE; ++CI) {
455    BV->push_back(CI->getVariable(), BC);
456  }
457
458  // Find the referenced global/static variables.
459  FindBlockDeclRefExprsVals F(*BV, BC);
460  F.Visit(BD->getBody());
461
462  Vec = BV;
463  return BV;
464}
465
466std::pair<AnalysisDeclContext::referenced_decls_iterator,
467          AnalysisDeclContext::referenced_decls_iterator>
468AnalysisDeclContext::getReferencedBlockVars(const BlockDecl *BD) {
469  if (!ReferencedBlockVars)
470    ReferencedBlockVars = new llvm::DenseMap<const BlockDecl*,void*>();
471
472  DeclVec *V = LazyInitializeReferencedDecls(BD, (*ReferencedBlockVars)[BD], A);
473  return std::make_pair(V->begin(), V->end());
474}
475
476ManagedAnalysis *&AnalysisDeclContext::getAnalysisImpl(const void *tag) {
477  if (!ManagedAnalyses)
478    ManagedAnalyses = new ManagedAnalysisMap();
479  ManagedAnalysisMap *M = (ManagedAnalysisMap*) ManagedAnalyses;
480  return (*M)[tag];
481}
482
483//===----------------------------------------------------------------------===//
484// Cleanup.
485//===----------------------------------------------------------------------===//
486
487ManagedAnalysis::~ManagedAnalysis() {}
488
489AnalysisDeclContext::~AnalysisDeclContext() {
490  delete forcedBlkExprs;
491  delete ReferencedBlockVars;
492  // Release the managed analyses.
493  if (ManagedAnalyses) {
494    ManagedAnalysisMap *M = (ManagedAnalysisMap*) ManagedAnalyses;
495    for (ManagedAnalysisMap::iterator I = M->begin(), E = M->end(); I!=E; ++I)
496      delete I->second;
497    delete M;
498  }
499}
500
501AnalysisDeclContextManager::~AnalysisDeclContextManager() {
502  for (ContextMap::iterator I = Contexts.begin(), E = Contexts.end(); I!=E; ++I)
503    delete I->second;
504}
505
506LocationContext::~LocationContext() {}
507
508LocationContextManager::~LocationContextManager() {
509  clear();
510}
511
512void LocationContextManager::clear() {
513  for (llvm::FoldingSet<LocationContext>::iterator I = Contexts.begin(),
514       E = Contexts.end(); I != E; ) {
515    LocationContext *LC = &*I;
516    ++I;
517    delete LC;
518  }
519
520  Contexts.clear();
521}
522
523