AnalysisDeclContext.cpp revision 49a246f4fad959888bb0164c624c3c2b03078e91 
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/raw_ostream.h"
32#include "llvm/Support/SaveAndRestore.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                                                       bool addStaticInitBranch)
72  : SynthesizeBodies(synthesizeBodies)
73{
74  cfgBuildOptions.PruneTriviallyFalseEdges = !useUnoptimizedCFG;
75  cfgBuildOptions.AddImplicitDtors = addImplicitDtors;
76  cfgBuildOptions.AddInitializers = addInitializers;
77  cfgBuildOptions.AddTemporaryDtors = addTemporaryDtors;
78  cfgBuildOptions.AddStaticInitBranches = addStaticInitBranch;
79}
80
81void AnalysisDeclContextManager::clear() {
82  for (ContextMap::iterator I = Contexts.begin(), E = Contexts.end(); I!=E; ++I)
83    delete I->second;
84  Contexts.clear();
85}
86
87static BodyFarm &getBodyFarm(ASTContext &C) {
88  static BodyFarm *BF = new BodyFarm(C);
89  return *BF;
90}
91
92Stmt *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      IsAutosynthesized = true;
98      return getBodyFarm(getASTContext()).getBody(FD);
99    }
100    return Body;
101  }
102  else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D))
103    return MD->getBody();
104  else if (const BlockDecl *BD = dyn_cast<BlockDecl>(D))
105    return BD->getBody();
106  else if (const FunctionTemplateDecl *FunTmpl
107           = dyn_cast_or_null<FunctionTemplateDecl>(D))
108    return FunTmpl->getTemplatedDecl()->getBody();
109
110  llvm_unreachable("unknown code decl");
111}
112
113Stmt *AnalysisDeclContext::getBody() const {
114  bool Tmp;
115  return getBody(Tmp);
116}
117
118bool AnalysisDeclContext::isBodyAutosynthesized() const {
119  bool Tmp;
120  getBody(Tmp);
121  return Tmp;
122}
123
124const ImplicitParamDecl *AnalysisDeclContext::getSelfDecl() const {
125  if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D))
126    return MD->getSelfDecl();
127  if (const BlockDecl *BD = dyn_cast<BlockDecl>(D)) {
128    // See if 'self' was captured by the block.
129    for (BlockDecl::capture_const_iterator it = BD->capture_begin(),
130         et = BD->capture_end(); it != et; ++it) {
131      const VarDecl *VD = it->getVariable();
132      if (VD->getName() == "self")
133        return dyn_cast<ImplicitParamDecl>(VD);
134    }
135  }
136
137  return NULL;
138}
139
140void AnalysisDeclContext::registerForcedBlockExpression(const Stmt *stmt) {
141  if (!forcedBlkExprs)
142    forcedBlkExprs = new CFG::BuildOptions::ForcedBlkExprs();
143  // Default construct an entry for 'stmt'.
144  if (const Expr *e = dyn_cast<Expr>(stmt))
145    stmt = e->IgnoreParens();
146  (void) (*forcedBlkExprs)[stmt];
147}
148
149const CFGBlock *
150AnalysisDeclContext::getBlockForRegisteredExpression(const Stmt *stmt) {
151  assert(forcedBlkExprs);
152  if (const Expr *e = dyn_cast<Expr>(stmt))
153    stmt = e->IgnoreParens();
154  CFG::BuildOptions::ForcedBlkExprs::const_iterator itr =
155    forcedBlkExprs->find(stmt);
156  assert(itr != forcedBlkExprs->end());
157  return itr->second;
158}
159
160/// Add each synthetic statement in the CFG to the parent map, using the
161/// source statement's parent.
162static void addParentsForSyntheticStmts(const CFG *TheCFG, ParentMap &PM) {
163  if (!TheCFG)
164    return;
165
166  for (CFG::synthetic_stmt_iterator I = TheCFG->synthetic_stmt_begin(),
167                                    E = TheCFG->synthetic_stmt_end();
168       I != E; ++I) {
169    PM.setParent(I->first, PM.getParent(I->second));
170  }
171}
172
173CFG *AnalysisDeclContext::getCFG() {
174  if (!cfgBuildOptions.PruneTriviallyFalseEdges)
175    return getUnoptimizedCFG();
176
177  if (!builtCFG) {
178    cfg.reset(CFG::buildCFG(D, getBody(),
179                            &D->getASTContext(), cfgBuildOptions));
180    // Even when the cfg is not successfully built, we don't
181    // want to try building it again.
182    builtCFG = true;
183
184    if (PM)
185      addParentsForSyntheticStmts(cfg.get(), *PM);
186  }
187  return cfg.get();
188}
189
190CFG *AnalysisDeclContext::getUnoptimizedCFG() {
191  if (!builtCompleteCFG) {
192    SaveAndRestore<bool> NotPrune(cfgBuildOptions.PruneTriviallyFalseEdges,
193                                  false);
194    completeCFG.reset(CFG::buildCFG(D, getBody(), &D->getASTContext(),
195                                    cfgBuildOptions));
196    // Even when the cfg is not successfully built, we don't
197    // want to try building it again.
198    builtCompleteCFG = true;
199
200    if (PM)
201      addParentsForSyntheticStmts(completeCFG.get(), *PM);
202  }
203  return completeCFG.get();
204}
205
206CFGStmtMap *AnalysisDeclContext::getCFGStmtMap() {
207  if (cfgStmtMap)
208    return cfgStmtMap.get();
209
210  if (CFG *c = getCFG()) {
211    cfgStmtMap.reset(CFGStmtMap::Build(c, &getParentMap()));
212    return cfgStmtMap.get();
213  }
214
215  return 0;
216}
217
218CFGReverseBlockReachabilityAnalysis *AnalysisDeclContext::getCFGReachablityAnalysis() {
219  if (CFA)
220    return CFA.get();
221
222  if (CFG *c = getCFG()) {
223    CFA.reset(new CFGReverseBlockReachabilityAnalysis(*c));
224    return CFA.get();
225  }
226
227  return 0;
228}
229
230void AnalysisDeclContext::dumpCFG(bool ShowColors) {
231    getCFG()->dump(getASTContext().getLangOpts(), ShowColors);
232}
233
234ParentMap &AnalysisDeclContext::getParentMap() {
235  if (!PM) {
236    PM.reset(new ParentMap(getBody()));
237    if (const CXXConstructorDecl *C = dyn_cast<CXXConstructorDecl>(getDecl())) {
238      for (CXXConstructorDecl::init_const_iterator I = C->init_begin(),
239                                                   E = C->init_end();
240           I != E; ++I) {
241        PM->addStmt((*I)->getInit());
242      }
243    }
244    if (builtCFG)
245      addParentsForSyntheticStmts(getCFG(), *PM);
246    if (builtCompleteCFG)
247      addParentsForSyntheticStmts(getUnoptimizedCFG(), *PM);
248  }
249  return *PM;
250}
251
252PseudoConstantAnalysis *AnalysisDeclContext::getPseudoConstantAnalysis() {
253  if (!PCA)
254    PCA.reset(new PseudoConstantAnalysis(getBody()));
255  return PCA.get();
256}
257
258AnalysisDeclContext *AnalysisDeclContextManager::getContext(const Decl *D) {
259  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
260    // Calling 'hasBody' replaces 'FD' in place with the FunctionDecl
261    // that has the body.
262    FD->hasBody(FD);
263    D = FD;
264  }
265
266  AnalysisDeclContext *&AC = Contexts[D];
267  if (!AC)
268    AC = new AnalysisDeclContext(this, D, cfgBuildOptions);
269  return AC;
270}
271
272const StackFrameContext *
273AnalysisDeclContext::getStackFrame(LocationContext const *Parent, const Stmt *S,
274                               const CFGBlock *Blk, unsigned Idx) {
275  return getLocationContextManager().getStackFrame(this, Parent, S, Blk, Idx);
276}
277
278const BlockInvocationContext *
279AnalysisDeclContext::getBlockInvocationContext(const LocationContext *parent,
280                                               const clang::BlockDecl *BD,
281                                               const void *ContextData) {
282  return getLocationContextManager().getBlockInvocationContext(this, parent,
283                                                               BD, ContextData);
284}
285
286LocationContextManager & AnalysisDeclContext::getLocationContextManager() {
287  assert(Manager &&
288         "Cannot create LocationContexts without an AnalysisDeclContextManager!");
289  return Manager->getLocationContextManager();
290}
291
292//===----------------------------------------------------------------------===//
293// FoldingSet profiling.
294//===----------------------------------------------------------------------===//
295
296void LocationContext::ProfileCommon(llvm::FoldingSetNodeID &ID,
297                                    ContextKind ck,
298                                    AnalysisDeclContext *ctx,
299                                    const LocationContext *parent,
300                                    const void *data) {
301  ID.AddInteger(ck);
302  ID.AddPointer(ctx);
303  ID.AddPointer(parent);
304  ID.AddPointer(data);
305}
306
307void StackFrameContext::Profile(llvm::FoldingSetNodeID &ID) {
308  Profile(ID, getAnalysisDeclContext(), getParent(), CallSite, Block, Index);
309}
310
311void ScopeContext::Profile(llvm::FoldingSetNodeID &ID) {
312  Profile(ID, getAnalysisDeclContext(), getParent(), Enter);
313}
314
315void BlockInvocationContext::Profile(llvm::FoldingSetNodeID &ID) {
316  Profile(ID, getAnalysisDeclContext(), getParent(), BD, ContextData);
317}
318
319//===----------------------------------------------------------------------===//
320// LocationContext creation.
321//===----------------------------------------------------------------------===//
322
323template <typename LOC, typename DATA>
324const LOC*
325LocationContextManager::getLocationContext(AnalysisDeclContext *ctx,
326                                           const LocationContext *parent,
327                                           const DATA *d) {
328  llvm::FoldingSetNodeID ID;
329  LOC::Profile(ID, ctx, parent, d);
330  void *InsertPos;
331
332  LOC *L = cast_or_null<LOC>(Contexts.FindNodeOrInsertPos(ID, InsertPos));
333
334  if (!L) {
335    L = new LOC(ctx, parent, d);
336    Contexts.InsertNode(L, InsertPos);
337  }
338  return L;
339}
340
341const StackFrameContext*
342LocationContextManager::getStackFrame(AnalysisDeclContext *ctx,
343                                      const LocationContext *parent,
344                                      const Stmt *s,
345                                      const CFGBlock *blk, unsigned idx) {
346  llvm::FoldingSetNodeID ID;
347  StackFrameContext::Profile(ID, ctx, parent, s, blk, idx);
348  void *InsertPos;
349  StackFrameContext *L =
350   cast_or_null<StackFrameContext>(Contexts.FindNodeOrInsertPos(ID, InsertPos));
351  if (!L) {
352    L = new StackFrameContext(ctx, parent, s, blk, idx);
353    Contexts.InsertNode(L, InsertPos);
354  }
355  return L;
356}
357
358const ScopeContext *
359LocationContextManager::getScope(AnalysisDeclContext *ctx,
360                                 const LocationContext *parent,
361                                 const Stmt *s) {
362  return getLocationContext<ScopeContext, Stmt>(ctx, parent, s);
363}
364
365const BlockInvocationContext *
366LocationContextManager::getBlockInvocationContext(AnalysisDeclContext *ctx,
367                                                  const LocationContext *parent,
368                                                  const BlockDecl *BD,
369                                                  const void *ContextData) {
370  llvm::FoldingSetNodeID ID;
371  BlockInvocationContext::Profile(ID, ctx, parent, BD, ContextData);
372  void *InsertPos;
373  BlockInvocationContext *L =
374    cast_or_null<BlockInvocationContext>(Contexts.FindNodeOrInsertPos(ID,
375                                                                    InsertPos));
376  if (!L) {
377    L = new BlockInvocationContext(ctx, parent, BD, ContextData);
378    Contexts.InsertNode(L, InsertPos);
379  }
380  return L;
381}
382
383//===----------------------------------------------------------------------===//
384// LocationContext methods.
385//===----------------------------------------------------------------------===//
386
387const StackFrameContext *LocationContext::getCurrentStackFrame() const {
388  const LocationContext *LC = this;
389  while (LC) {
390    if (const StackFrameContext *SFC = dyn_cast<StackFrameContext>(LC))
391      return SFC;
392    LC = LC->getParent();
393  }
394  return NULL;
395}
396
397bool LocationContext::inTopFrame() const {
398  return getCurrentStackFrame()->inTopFrame();
399}
400
401bool LocationContext::isParentOf(const LocationContext *LC) const {
402  do {
403    const LocationContext *Parent = LC->getParent();
404    if (Parent == this)
405      return true;
406    else
407      LC = Parent;
408  } while (LC);
409
410  return false;
411}
412
413void LocationContext::dumpStack() const {
414  ASTContext &Ctx = getAnalysisDeclContext()->getASTContext();
415  PrintingPolicy PP(Ctx.getLangOpts());
416  PP.TerseOutput = 1;
417
418  unsigned Frame = 0;
419  for (const LocationContext *LCtx = this; LCtx; LCtx = LCtx->getParent()) {
420    switch (LCtx->getKind()) {
421    case StackFrame:
422      llvm::errs() << '#' << Frame++ << ' ';
423      cast<StackFrameContext>(LCtx)->getDecl()->print(llvm::errs(), PP);
424      llvm::errs() << '\n';
425      break;
426    case Scope:
427      llvm::errs() << "    (scope)\n";
428      break;
429    case Block:
430      llvm::errs() << "    (block context: "
431                   << cast<BlockInvocationContext>(LCtx)->getContextData()
432                   << ")\n";
433      break;
434    }
435  }
436}
437
438//===----------------------------------------------------------------------===//
439// Lazily generated map to query the external variables referenced by a Block.
440//===----------------------------------------------------------------------===//
441
442namespace {
443class FindBlockDeclRefExprsVals : public StmtVisitor<FindBlockDeclRefExprsVals>{
444  BumpVector<const VarDecl*> &BEVals;
445  BumpVectorContext &BC;
446  llvm::SmallPtrSet<const VarDecl*, 4> Visited;
447  llvm::SmallPtrSet<const DeclContext*, 4> IgnoredContexts;
448public:
449  FindBlockDeclRefExprsVals(BumpVector<const VarDecl*> &bevals,
450                            BumpVectorContext &bc)
451  : BEVals(bevals), BC(bc) {}
452
453  bool IsTrackedDecl(const VarDecl *VD) {
454    const DeclContext *DC = VD->getDeclContext();
455    return IgnoredContexts.count(DC) == 0;
456  }
457
458  void VisitStmt(Stmt *S) {
459    for (Stmt::child_range I = S->children(); I; ++I)
460      if (Stmt *child = *I)
461        Visit(child);
462  }
463
464  void VisitDeclRefExpr(DeclRefExpr *DR) {
465    // Non-local variables are also directly modified.
466    if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) {
467      if (!VD->hasLocalStorage()) {
468        if (Visited.insert(VD))
469          BEVals.push_back(VD, BC);
470      }
471    }
472  }
473
474  void VisitBlockExpr(BlockExpr *BR) {
475    // Blocks containing blocks can transitively capture more variables.
476    IgnoredContexts.insert(BR->getBlockDecl());
477    Visit(BR->getBlockDecl()->getBody());
478  }
479
480  void VisitPseudoObjectExpr(PseudoObjectExpr *PE) {
481    for (PseudoObjectExpr::semantics_iterator it = PE->semantics_begin(),
482         et = PE->semantics_end(); it != et; ++it) {
483      Expr *Semantic = *it;
484      if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic))
485        Semantic = OVE->getSourceExpr();
486      Visit(Semantic);
487    }
488  }
489};
490} // end anonymous namespace
491
492typedef BumpVector<const VarDecl*> DeclVec;
493
494static DeclVec* LazyInitializeReferencedDecls(const BlockDecl *BD,
495                                              void *&Vec,
496                                              llvm::BumpPtrAllocator &A) {
497  if (Vec)
498    return (DeclVec*) Vec;
499
500  BumpVectorContext BC(A);
501  DeclVec *BV = (DeclVec*) A.Allocate<DeclVec>();
502  new (BV) DeclVec(BC, 10);
503
504  // Go through the capture list.
505  for (BlockDecl::capture_const_iterator CI = BD->capture_begin(),
506       CE = BD->capture_end(); CI != CE; ++CI) {
507    BV->push_back(CI->getVariable(), BC);
508  }
509
510  // Find the referenced global/static variables.
511  FindBlockDeclRefExprsVals F(*BV, BC);
512  F.Visit(BD->getBody());
513
514  Vec = BV;
515  return BV;
516}
517
518std::pair<AnalysisDeclContext::referenced_decls_iterator,
519          AnalysisDeclContext::referenced_decls_iterator>
520AnalysisDeclContext::getReferencedBlockVars(const BlockDecl *BD) {
521  if (!ReferencedBlockVars)
522    ReferencedBlockVars = new llvm::DenseMap<const BlockDecl*,void*>();
523
524  DeclVec *V = LazyInitializeReferencedDecls(BD, (*ReferencedBlockVars)[BD], A);
525  return std::make_pair(V->begin(), V->end());
526}
527
528ManagedAnalysis *&AnalysisDeclContext::getAnalysisImpl(const void *tag) {
529  if (!ManagedAnalyses)
530    ManagedAnalyses = new ManagedAnalysisMap();
531  ManagedAnalysisMap *M = (ManagedAnalysisMap*) ManagedAnalyses;
532  return (*M)[tag];
533}
534
535//===----------------------------------------------------------------------===//
536// Cleanup.
537//===----------------------------------------------------------------------===//
538
539ManagedAnalysis::~ManagedAnalysis() {}
540
541AnalysisDeclContext::~AnalysisDeclContext() {
542  delete forcedBlkExprs;
543  delete ReferencedBlockVars;
544  // Release the managed analyses.
545  if (ManagedAnalyses) {
546    ManagedAnalysisMap *M = (ManagedAnalysisMap*) ManagedAnalyses;
547    for (ManagedAnalysisMap::iterator I = M->begin(), E = M->end(); I!=E; ++I)
548      delete I->second;
549    delete M;
550  }
551}
552
553AnalysisDeclContextManager::~AnalysisDeclContextManager() {
554  for (ContextMap::iterator I = Contexts.begin(), E = Contexts.end(); I!=E; ++I)
555    delete I->second;
556}
557
558LocationContext::~LocationContext() {}
559
560LocationContextManager::~LocationContextManager() {
561  clear();
562}
563
564void LocationContextManager::clear() {
565  for (llvm::FoldingSet<LocationContext>::iterator I = Contexts.begin(),
566       E = Contexts.end(); I != E; ) {
567    LocationContext *LC = &*I;
568    ++I;
569    delete LC;
570  }
571
572  Contexts.clear();
573}
574
575