AnalysisDeclContext.cpp revision 75f8bd01319000b3e1438847505302670514759d 
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
160CFG *AnalysisDeclContext::getCFG() {
161  if (!cfgBuildOptions.PruneTriviallyFalseEdges)
162    return getUnoptimizedCFG();
163
164  if (!builtCFG) {
165    cfg.reset(CFG::buildCFG(D, getBody(),
166                            &D->getASTContext(), cfgBuildOptions));
167    // Even when the cfg is not successfully built, we don't
168    // want to try building it again.
169    builtCFG = true;
170  }
171  return cfg.get();
172}
173
174CFG *AnalysisDeclContext::getUnoptimizedCFG() {
175  if (!builtCompleteCFG) {
176    SaveAndRestore<bool> NotPrune(cfgBuildOptions.PruneTriviallyFalseEdges,
177                                  false);
178    completeCFG.reset(CFG::buildCFG(D, getBody(), &D->getASTContext(),
179                                    cfgBuildOptions));
180    // Even when the cfg is not successfully built, we don't
181    // want to try building it again.
182    builtCompleteCFG = true;
183  }
184  return completeCFG.get();
185}
186
187CFGStmtMap *AnalysisDeclContext::getCFGStmtMap() {
188  if (cfgStmtMap)
189    return cfgStmtMap.get();
190
191  if (CFG *c = getCFG()) {
192    cfgStmtMap.reset(CFGStmtMap::Build(c, &getParentMap()));
193    return cfgStmtMap.get();
194  }
195
196  return 0;
197}
198
199CFGReverseBlockReachabilityAnalysis *AnalysisDeclContext::getCFGReachablityAnalysis() {
200  if (CFA)
201    return CFA.get();
202
203  if (CFG *c = getCFG()) {
204    CFA.reset(new CFGReverseBlockReachabilityAnalysis(*c));
205    return CFA.get();
206  }
207
208  return 0;
209}
210
211void AnalysisDeclContext::dumpCFG(bool ShowColors) {
212    getCFG()->dump(getASTContext().getLangOpts(), ShowColors);
213}
214
215ParentMap &AnalysisDeclContext::getParentMap() {
216  if (!PM) {
217    PM.reset(new ParentMap(getBody()));
218    if (const CXXConstructorDecl *C = dyn_cast<CXXConstructorDecl>(getDecl())) {
219      for (CXXConstructorDecl::init_const_iterator I = C->init_begin(),
220                                                   E = C->init_end();
221           I != E; ++I) {
222        PM->addStmt((*I)->getInit());
223      }
224    }
225  }
226  return *PM;
227}
228
229PseudoConstantAnalysis *AnalysisDeclContext::getPseudoConstantAnalysis() {
230  if (!PCA)
231    PCA.reset(new PseudoConstantAnalysis(getBody()));
232  return PCA.get();
233}
234
235AnalysisDeclContext *AnalysisDeclContextManager::getContext(const Decl *D) {
236  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
237    // Calling 'hasBody' replaces 'FD' in place with the FunctionDecl
238    // that has the body.
239    FD->hasBody(FD);
240    D = FD;
241  }
242
243  AnalysisDeclContext *&AC = Contexts[D];
244  if (!AC)
245    AC = new AnalysisDeclContext(this, D, cfgBuildOptions);
246  return AC;
247}
248
249const StackFrameContext *
250AnalysisDeclContext::getStackFrame(LocationContext const *Parent, const Stmt *S,
251                               const CFGBlock *Blk, unsigned Idx) {
252  return getLocationContextManager().getStackFrame(this, Parent, S, Blk, Idx);
253}
254
255const BlockInvocationContext *
256AnalysisDeclContext::getBlockInvocationContext(const LocationContext *parent,
257                                               const clang::BlockDecl *BD,
258                                               const void *ContextData) {
259  return getLocationContextManager().getBlockInvocationContext(this, parent,
260                                                               BD, ContextData);
261}
262
263LocationContextManager & AnalysisDeclContext::getLocationContextManager() {
264  assert(Manager &&
265         "Cannot create LocationContexts without an AnalysisDeclContextManager!");
266  return Manager->getLocationContextManager();
267}
268
269//===----------------------------------------------------------------------===//
270// FoldingSet profiling.
271//===----------------------------------------------------------------------===//
272
273void LocationContext::ProfileCommon(llvm::FoldingSetNodeID &ID,
274                                    ContextKind ck,
275                                    AnalysisDeclContext *ctx,
276                                    const LocationContext *parent,
277                                    const void *data) {
278  ID.AddInteger(ck);
279  ID.AddPointer(ctx);
280  ID.AddPointer(parent);
281  ID.AddPointer(data);
282}
283
284void StackFrameContext::Profile(llvm::FoldingSetNodeID &ID) {
285  Profile(ID, getAnalysisDeclContext(), getParent(), CallSite, Block, Index);
286}
287
288void ScopeContext::Profile(llvm::FoldingSetNodeID &ID) {
289  Profile(ID, getAnalysisDeclContext(), getParent(), Enter);
290}
291
292void BlockInvocationContext::Profile(llvm::FoldingSetNodeID &ID) {
293  Profile(ID, getAnalysisDeclContext(), getParent(), BD, ContextData);
294}
295
296//===----------------------------------------------------------------------===//
297// LocationContext creation.
298//===----------------------------------------------------------------------===//
299
300template <typename LOC, typename DATA>
301const LOC*
302LocationContextManager::getLocationContext(AnalysisDeclContext *ctx,
303                                           const LocationContext *parent,
304                                           const DATA *d) {
305  llvm::FoldingSetNodeID ID;
306  LOC::Profile(ID, ctx, parent, d);
307  void *InsertPos;
308
309  LOC *L = cast_or_null<LOC>(Contexts.FindNodeOrInsertPos(ID, InsertPos));
310
311  if (!L) {
312    L = new LOC(ctx, parent, d);
313    Contexts.InsertNode(L, InsertPos);
314  }
315  return L;
316}
317
318const StackFrameContext*
319LocationContextManager::getStackFrame(AnalysisDeclContext *ctx,
320                                      const LocationContext *parent,
321                                      const Stmt *s,
322                                      const CFGBlock *blk, unsigned idx) {
323  llvm::FoldingSetNodeID ID;
324  StackFrameContext::Profile(ID, ctx, parent, s, blk, idx);
325  void *InsertPos;
326  StackFrameContext *L =
327   cast_or_null<StackFrameContext>(Contexts.FindNodeOrInsertPos(ID, InsertPos));
328  if (!L) {
329    L = new StackFrameContext(ctx, parent, s, blk, idx);
330    Contexts.InsertNode(L, InsertPos);
331  }
332  return L;
333}
334
335const ScopeContext *
336LocationContextManager::getScope(AnalysisDeclContext *ctx,
337                                 const LocationContext *parent,
338                                 const Stmt *s) {
339  return getLocationContext<ScopeContext, Stmt>(ctx, parent, s);
340}
341
342const BlockInvocationContext *
343LocationContextManager::getBlockInvocationContext(AnalysisDeclContext *ctx,
344                                                  const LocationContext *parent,
345                                                  const BlockDecl *BD,
346                                                  const void *ContextData) {
347  llvm::FoldingSetNodeID ID;
348  BlockInvocationContext::Profile(ID, ctx, parent, BD, ContextData);
349  void *InsertPos;
350  BlockInvocationContext *L =
351    cast_or_null<BlockInvocationContext>(Contexts.FindNodeOrInsertPos(ID,
352                                                                    InsertPos));
353  if (!L) {
354    L = new BlockInvocationContext(ctx, parent, BD, ContextData);
355    Contexts.InsertNode(L, InsertPos);
356  }
357  return L;
358}
359
360//===----------------------------------------------------------------------===//
361// LocationContext methods.
362//===----------------------------------------------------------------------===//
363
364const StackFrameContext *LocationContext::getCurrentStackFrame() const {
365  const LocationContext *LC = this;
366  while (LC) {
367    if (const StackFrameContext *SFC = dyn_cast<StackFrameContext>(LC))
368      return SFC;
369    LC = LC->getParent();
370  }
371  return NULL;
372}
373
374bool LocationContext::inTopFrame() const {
375  return getCurrentStackFrame()->inTopFrame();
376}
377
378bool LocationContext::isParentOf(const LocationContext *LC) const {
379  do {
380    const LocationContext *Parent = LC->getParent();
381    if (Parent == this)
382      return true;
383    else
384      LC = Parent;
385  } while (LC);
386
387  return false;
388}
389
390void LocationContext::dumpStack() const {
391  ASTContext &Ctx = getAnalysisDeclContext()->getASTContext();
392  PrintingPolicy PP(Ctx.getLangOpts());
393  PP.TerseOutput = 1;
394
395  unsigned Frame = 0;
396  for (const LocationContext *LCtx = this; LCtx; LCtx = LCtx->getParent()) {
397    switch (LCtx->getKind()) {
398    case StackFrame:
399      llvm::errs() << '#' << Frame++ << ' ';
400      cast<StackFrameContext>(LCtx)->getDecl()->print(llvm::errs(), PP);
401      llvm::errs() << '\n';
402      break;
403    case Scope:
404      llvm::errs() << "    (scope)\n";
405      break;
406    case Block:
407      llvm::errs() << "    (block context: "
408                   << cast<BlockInvocationContext>(LCtx)->getContextData()
409                   << ")\n";
410      break;
411    }
412  }
413}
414
415//===----------------------------------------------------------------------===//
416// Lazily generated map to query the external variables referenced by a Block.
417//===----------------------------------------------------------------------===//
418
419namespace {
420class FindBlockDeclRefExprsVals : public StmtVisitor<FindBlockDeclRefExprsVals>{
421  BumpVector<const VarDecl*> &BEVals;
422  BumpVectorContext &BC;
423  llvm::SmallPtrSet<const VarDecl*, 4> Visited;
424  llvm::SmallPtrSet<const DeclContext*, 4> IgnoredContexts;
425public:
426  FindBlockDeclRefExprsVals(BumpVector<const VarDecl*> &bevals,
427                            BumpVectorContext &bc)
428  : BEVals(bevals), BC(bc) {}
429
430  bool IsTrackedDecl(const VarDecl *VD) {
431    const DeclContext *DC = VD->getDeclContext();
432    return IgnoredContexts.count(DC) == 0;
433  }
434
435  void VisitStmt(Stmt *S) {
436    for (Stmt::child_range I = S->children(); I; ++I)
437      if (Stmt *child = *I)
438        Visit(child);
439  }
440
441  void VisitDeclRefExpr(DeclRefExpr *DR) {
442    // Non-local variables are also directly modified.
443    if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) {
444      if (!VD->hasLocalStorage()) {
445        if (Visited.insert(VD))
446          BEVals.push_back(VD, BC);
447      }
448    }
449  }
450
451  void VisitBlockExpr(BlockExpr *BR) {
452    // Blocks containing blocks can transitively capture more variables.
453    IgnoredContexts.insert(BR->getBlockDecl());
454    Visit(BR->getBlockDecl()->getBody());
455  }
456
457  void VisitPseudoObjectExpr(PseudoObjectExpr *PE) {
458    for (PseudoObjectExpr::semantics_iterator it = PE->semantics_begin(),
459         et = PE->semantics_end(); it != et; ++it) {
460      Expr *Semantic = *it;
461      if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic))
462        Semantic = OVE->getSourceExpr();
463      Visit(Semantic);
464    }
465  }
466};
467} // end anonymous namespace
468
469typedef BumpVector<const VarDecl*> DeclVec;
470
471static DeclVec* LazyInitializeReferencedDecls(const BlockDecl *BD,
472                                              void *&Vec,
473                                              llvm::BumpPtrAllocator &A) {
474  if (Vec)
475    return (DeclVec*) Vec;
476
477  BumpVectorContext BC(A);
478  DeclVec *BV = (DeclVec*) A.Allocate<DeclVec>();
479  new (BV) DeclVec(BC, 10);
480
481  // Go through the capture list.
482  for (BlockDecl::capture_const_iterator CI = BD->capture_begin(),
483       CE = BD->capture_end(); CI != CE; ++CI) {
484    BV->push_back(CI->getVariable(), BC);
485  }
486
487  // Find the referenced global/static variables.
488  FindBlockDeclRefExprsVals F(*BV, BC);
489  F.Visit(BD->getBody());
490
491  Vec = BV;
492  return BV;
493}
494
495std::pair<AnalysisDeclContext::referenced_decls_iterator,
496          AnalysisDeclContext::referenced_decls_iterator>
497AnalysisDeclContext::getReferencedBlockVars(const BlockDecl *BD) {
498  if (!ReferencedBlockVars)
499    ReferencedBlockVars = new llvm::DenseMap<const BlockDecl*,void*>();
500
501  DeclVec *V = LazyInitializeReferencedDecls(BD, (*ReferencedBlockVars)[BD], A);
502  return std::make_pair(V->begin(), V->end());
503}
504
505ManagedAnalysis *&AnalysisDeclContext::getAnalysisImpl(const void *tag) {
506  if (!ManagedAnalyses)
507    ManagedAnalyses = new ManagedAnalysisMap();
508  ManagedAnalysisMap *M = (ManagedAnalysisMap*) ManagedAnalyses;
509  return (*M)[tag];
510}
511
512//===----------------------------------------------------------------------===//
513// Cleanup.
514//===----------------------------------------------------------------------===//
515
516ManagedAnalysis::~ManagedAnalysis() {}
517
518AnalysisDeclContext::~AnalysisDeclContext() {
519  delete forcedBlkExprs;
520  delete ReferencedBlockVars;
521  // Release the managed analyses.
522  if (ManagedAnalyses) {
523    ManagedAnalysisMap *M = (ManagedAnalysisMap*) ManagedAnalyses;
524    for (ManagedAnalysisMap::iterator I = M->begin(), E = M->end(); I!=E; ++I)
525      delete I->second;
526    delete M;
527  }
528}
529
530AnalysisDeclContextManager::~AnalysisDeclContextManager() {
531  for (ContextMap::iterator I = Contexts.begin(), E = Contexts.end(); I!=E; ++I)
532    delete I->second;
533}
534
535LocationContext::~LocationContext() {}
536
537LocationContextManager::~LocationContextManager() {
538  clear();
539}
540
541void LocationContextManager::clear() {
542  for (llvm::FoldingSet<LocationContext>::iterator I = Contexts.begin(),
543       E = Contexts.end(); I != E; ) {
544    LocationContext *LC = &*I;
545    ++I;
546    delete LC;
547  }
548
549  Contexts.clear();
550}
551
552