AnalysisDeclContext.cpp revision 176edba5311f6eff0cad2631449885ddf4fbc9ea 
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#include "llvm/Support/raw_ostream.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(nullptr),
45    builtCFG(false),
46    builtCompleteCFG(false),
47    ReferencedBlockVars(nullptr),
48    ManagedAnalyses(nullptr)
49{
50  cfgBuildOptions.forcedBlkExprs = &forcedBlkExprs;
51}
52
53AnalysisDeclContext::AnalysisDeclContext(AnalysisDeclContextManager *Mgr,
54                                         const Decl *d)
55: Manager(Mgr),
56  D(d),
57  forcedBlkExprs(nullptr),
58  builtCFG(false),
59  builtCompleteCFG(false),
60  ReferencedBlockVars(nullptr),
61  ManagedAnalyses(nullptr)
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                                                       bool addCXXNewAllocator,
73                                                       CodeInjector *injector)
74  : Injector(injector), SynthesizeBodies(synthesizeBodies)
75{
76  cfgBuildOptions.PruneTriviallyFalseEdges = !useUnoptimizedCFG;
77  cfgBuildOptions.AddImplicitDtors = addImplicitDtors;
78  cfgBuildOptions.AddInitializers = addInitializers;
79  cfgBuildOptions.AddTemporaryDtors = addTemporaryDtors;
80  cfgBuildOptions.AddStaticInitBranches = addStaticInitBranch;
81  cfgBuildOptions.AddCXXNewAllocator = addCXXNewAllocator;
82}
83
84void AnalysisDeclContextManager::clear() {
85  llvm::DeleteContainerSeconds(Contexts);
86}
87
88static BodyFarm &getBodyFarm(ASTContext &C, CodeInjector *injector = nullptr) {
89  static BodyFarm *BF = new BodyFarm(C, injector);
90  return *BF;
91}
92
93Stmt *AnalysisDeclContext::getBody(bool &IsAutosynthesized) const {
94  IsAutosynthesized = false;
95  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
96    Stmt *Body = FD->getBody();
97    if (!Body && Manager && Manager->synthesizeBodies()) {
98      Body = getBodyFarm(getASTContext(), Manager->Injector.get()).getBody(FD);
99      if (Body)
100        IsAutosynthesized = true;
101    }
102    return Body;
103  }
104  else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
105    Stmt *Body = MD->getBody();
106    if (!Body && Manager && Manager->synthesizeBodies()) {
107      Body = getBodyFarm(getASTContext(), Manager->Injector.get()).getBody(MD);
108      if (Body)
109        IsAutosynthesized = true;
110    }
111    return Body;
112  } else if (const BlockDecl *BD = dyn_cast<BlockDecl>(D))
113    return BD->getBody();
114  else if (const FunctionTemplateDecl *FunTmpl
115           = dyn_cast_or_null<FunctionTemplateDecl>(D))
116    return FunTmpl->getTemplatedDecl()->getBody();
117
118  llvm_unreachable("unknown code decl");
119}
120
121Stmt *AnalysisDeclContext::getBody() const {
122  bool Tmp;
123  return getBody(Tmp);
124}
125
126bool AnalysisDeclContext::isBodyAutosynthesized() const {
127  bool Tmp;
128  getBody(Tmp);
129  return Tmp;
130}
131
132bool AnalysisDeclContext::isBodyAutosynthesizedFromModelFile() const {
133  bool Tmp;
134  Stmt *Body = getBody(Tmp);
135  return Tmp && Body->getLocStart().isValid();
136}
137
138
139const ImplicitParamDecl *AnalysisDeclContext::getSelfDecl() const {
140  if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D))
141    return MD->getSelfDecl();
142  if (const BlockDecl *BD = dyn_cast<BlockDecl>(D)) {
143    // See if 'self' was captured by the block.
144    for (const auto &I : BD->captures()) {
145      const VarDecl *VD = I.getVariable();
146      if (VD->getName() == "self")
147        return dyn_cast<ImplicitParamDecl>(VD);
148    }
149  }
150
151  return nullptr;
152}
153
154void AnalysisDeclContext::registerForcedBlockExpression(const Stmt *stmt) {
155  if (!forcedBlkExprs)
156    forcedBlkExprs = new CFG::BuildOptions::ForcedBlkExprs();
157  // Default construct an entry for 'stmt'.
158  if (const Expr *e = dyn_cast<Expr>(stmt))
159    stmt = e->IgnoreParens();
160  (void) (*forcedBlkExprs)[stmt];
161}
162
163const CFGBlock *
164AnalysisDeclContext::getBlockForRegisteredExpression(const Stmt *stmt) {
165  assert(forcedBlkExprs);
166  if (const Expr *e = dyn_cast<Expr>(stmt))
167    stmt = e->IgnoreParens();
168  CFG::BuildOptions::ForcedBlkExprs::const_iterator itr =
169    forcedBlkExprs->find(stmt);
170  assert(itr != forcedBlkExprs->end());
171  return itr->second;
172}
173
174/// Add each synthetic statement in the CFG to the parent map, using the
175/// source statement's parent.
176static void addParentsForSyntheticStmts(const CFG *TheCFG, ParentMap &PM) {
177  if (!TheCFG)
178    return;
179
180  for (CFG::synthetic_stmt_iterator I = TheCFG->synthetic_stmt_begin(),
181                                    E = TheCFG->synthetic_stmt_end();
182       I != E; ++I) {
183    PM.setParent(I->first, PM.getParent(I->second));
184  }
185}
186
187CFG *AnalysisDeclContext::getCFG() {
188  if (!cfgBuildOptions.PruneTriviallyFalseEdges)
189    return getUnoptimizedCFG();
190
191  if (!builtCFG) {
192    cfg = CFG::buildCFG(D, getBody(), &D->getASTContext(), cfgBuildOptions);
193    // Even when the cfg is not successfully built, we don't
194    // want to try building it again.
195    builtCFG = true;
196
197    if (PM)
198      addParentsForSyntheticStmts(cfg.get(), *PM);
199
200    // The Observer should only observe one build of the CFG.
201    getCFGBuildOptions().Observer = nullptr;
202  }
203  return cfg.get();
204}
205
206CFG *AnalysisDeclContext::getUnoptimizedCFG() {
207  if (!builtCompleteCFG) {
208    SaveAndRestore<bool> NotPrune(cfgBuildOptions.PruneTriviallyFalseEdges,
209                                  false);
210    completeCFG =
211        CFG::buildCFG(D, getBody(), &D->getASTContext(), cfgBuildOptions);
212    // Even when the cfg is not successfully built, we don't
213    // want to try building it again.
214    builtCompleteCFG = true;
215
216    if (PM)
217      addParentsForSyntheticStmts(completeCFG.get(), *PM);
218
219    // The Observer should only observe one build of the CFG.
220    getCFGBuildOptions().Observer = nullptr;
221  }
222  return completeCFG.get();
223}
224
225CFGStmtMap *AnalysisDeclContext::getCFGStmtMap() {
226  if (cfgStmtMap)
227    return cfgStmtMap.get();
228
229  if (CFG *c = getCFG()) {
230    cfgStmtMap.reset(CFGStmtMap::Build(c, &getParentMap()));
231    return cfgStmtMap.get();
232  }
233
234  return nullptr;
235}
236
237CFGReverseBlockReachabilityAnalysis *AnalysisDeclContext::getCFGReachablityAnalysis() {
238  if (CFA)
239    return CFA.get();
240
241  if (CFG *c = getCFG()) {
242    CFA.reset(new CFGReverseBlockReachabilityAnalysis(*c));
243    return CFA.get();
244  }
245
246  return nullptr;
247}
248
249void AnalysisDeclContext::dumpCFG(bool ShowColors) {
250    getCFG()->dump(getASTContext().getLangOpts(), ShowColors);
251}
252
253ParentMap &AnalysisDeclContext::getParentMap() {
254  if (!PM) {
255    PM.reset(new ParentMap(getBody()));
256    if (const CXXConstructorDecl *C = dyn_cast<CXXConstructorDecl>(getDecl())) {
257      for (const auto *I : C->inits()) {
258        PM->addStmt(I->getInit());
259      }
260    }
261    if (builtCFG)
262      addParentsForSyntheticStmts(getCFG(), *PM);
263    if (builtCompleteCFG)
264      addParentsForSyntheticStmts(getUnoptimizedCFG(), *PM);
265  }
266  return *PM;
267}
268
269PseudoConstantAnalysis *AnalysisDeclContext::getPseudoConstantAnalysis() {
270  if (!PCA)
271    PCA.reset(new PseudoConstantAnalysis(getBody()));
272  return PCA.get();
273}
274
275AnalysisDeclContext *AnalysisDeclContextManager::getContext(const Decl *D) {
276  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
277    // Calling 'hasBody' replaces 'FD' in place with the FunctionDecl
278    // that has the body.
279    FD->hasBody(FD);
280    D = FD;
281  }
282
283  AnalysisDeclContext *&AC = Contexts[D];
284  if (!AC)
285    AC = new AnalysisDeclContext(this, D, cfgBuildOptions);
286  return AC;
287}
288
289const StackFrameContext *
290AnalysisDeclContext::getStackFrame(LocationContext const *Parent, const Stmt *S,
291                               const CFGBlock *Blk, unsigned Idx) {
292  return getLocationContextManager().getStackFrame(this, Parent, S, Blk, Idx);
293}
294
295const BlockInvocationContext *
296AnalysisDeclContext::getBlockInvocationContext(const LocationContext *parent,
297                                               const clang::BlockDecl *BD,
298                                               const void *ContextData) {
299  return getLocationContextManager().getBlockInvocationContext(this, parent,
300                                                               BD, ContextData);
301}
302
303LocationContextManager & AnalysisDeclContext::getLocationContextManager() {
304  assert(Manager &&
305         "Cannot create LocationContexts without an AnalysisDeclContextManager!");
306  return Manager->getLocationContextManager();
307}
308
309//===----------------------------------------------------------------------===//
310// FoldingSet profiling.
311//===----------------------------------------------------------------------===//
312
313void LocationContext::ProfileCommon(llvm::FoldingSetNodeID &ID,
314                                    ContextKind ck,
315                                    AnalysisDeclContext *ctx,
316                                    const LocationContext *parent,
317                                    const void *data) {
318  ID.AddInteger(ck);
319  ID.AddPointer(ctx);
320  ID.AddPointer(parent);
321  ID.AddPointer(data);
322}
323
324void StackFrameContext::Profile(llvm::FoldingSetNodeID &ID) {
325  Profile(ID, getAnalysisDeclContext(), getParent(), CallSite, Block, Index);
326}
327
328void ScopeContext::Profile(llvm::FoldingSetNodeID &ID) {
329  Profile(ID, getAnalysisDeclContext(), getParent(), Enter);
330}
331
332void BlockInvocationContext::Profile(llvm::FoldingSetNodeID &ID) {
333  Profile(ID, getAnalysisDeclContext(), getParent(), BD, ContextData);
334}
335
336//===----------------------------------------------------------------------===//
337// LocationContext creation.
338//===----------------------------------------------------------------------===//
339
340template <typename LOC, typename DATA>
341const LOC*
342LocationContextManager::getLocationContext(AnalysisDeclContext *ctx,
343                                           const LocationContext *parent,
344                                           const DATA *d) {
345  llvm::FoldingSetNodeID ID;
346  LOC::Profile(ID, ctx, parent, d);
347  void *InsertPos;
348
349  LOC *L = cast_or_null<LOC>(Contexts.FindNodeOrInsertPos(ID, InsertPos));
350
351  if (!L) {
352    L = new LOC(ctx, parent, d);
353    Contexts.InsertNode(L, InsertPos);
354  }
355  return L;
356}
357
358const StackFrameContext*
359LocationContextManager::getStackFrame(AnalysisDeclContext *ctx,
360                                      const LocationContext *parent,
361                                      const Stmt *s,
362                                      const CFGBlock *blk, unsigned idx) {
363  llvm::FoldingSetNodeID ID;
364  StackFrameContext::Profile(ID, ctx, parent, s, blk, idx);
365  void *InsertPos;
366  StackFrameContext *L =
367   cast_or_null<StackFrameContext>(Contexts.FindNodeOrInsertPos(ID, InsertPos));
368  if (!L) {
369    L = new StackFrameContext(ctx, parent, s, blk, idx);
370    Contexts.InsertNode(L, InsertPos);
371  }
372  return L;
373}
374
375const ScopeContext *
376LocationContextManager::getScope(AnalysisDeclContext *ctx,
377                                 const LocationContext *parent,
378                                 const Stmt *s) {
379  return getLocationContext<ScopeContext, Stmt>(ctx, parent, s);
380}
381
382const BlockInvocationContext *
383LocationContextManager::getBlockInvocationContext(AnalysisDeclContext *ctx,
384                                                  const LocationContext *parent,
385                                                  const BlockDecl *BD,
386                                                  const void *ContextData) {
387  llvm::FoldingSetNodeID ID;
388  BlockInvocationContext::Profile(ID, ctx, parent, BD, ContextData);
389  void *InsertPos;
390  BlockInvocationContext *L =
391    cast_or_null<BlockInvocationContext>(Contexts.FindNodeOrInsertPos(ID,
392                                                                    InsertPos));
393  if (!L) {
394    L = new BlockInvocationContext(ctx, parent, BD, ContextData);
395    Contexts.InsertNode(L, InsertPos);
396  }
397  return L;
398}
399
400//===----------------------------------------------------------------------===//
401// LocationContext methods.
402//===----------------------------------------------------------------------===//
403
404const StackFrameContext *LocationContext::getCurrentStackFrame() const {
405  const LocationContext *LC = this;
406  while (LC) {
407    if (const StackFrameContext *SFC = dyn_cast<StackFrameContext>(LC))
408      return SFC;
409    LC = LC->getParent();
410  }
411  return nullptr;
412}
413
414bool LocationContext::inTopFrame() const {
415  return getCurrentStackFrame()->inTopFrame();
416}
417
418bool LocationContext::isParentOf(const LocationContext *LC) const {
419  do {
420    const LocationContext *Parent = LC->getParent();
421    if (Parent == this)
422      return true;
423    else
424      LC = Parent;
425  } while (LC);
426
427  return false;
428}
429
430void LocationContext::dumpStack(raw_ostream &OS, StringRef Indent) const {
431  ASTContext &Ctx = getAnalysisDeclContext()->getASTContext();
432  PrintingPolicy PP(Ctx.getLangOpts());
433  PP.TerseOutput = 1;
434
435  unsigned Frame = 0;
436  for (const LocationContext *LCtx = this; LCtx; LCtx = LCtx->getParent()) {
437    switch (LCtx->getKind()) {
438    case StackFrame:
439      OS << Indent << '#' << Frame++ << ' ';
440      cast<StackFrameContext>(LCtx)->getDecl()->print(OS, PP);
441      OS << '\n';
442      break;
443    case Scope:
444      OS << Indent << "    (scope)\n";
445      break;
446    case Block:
447      OS << Indent << "    (block context: "
448                   << cast<BlockInvocationContext>(LCtx)->getContextData()
449                   << ")\n";
450      break;
451    }
452  }
453}
454
455LLVM_DUMP_METHOD void LocationContext::dumpStack() const {
456  dumpStack(llvm::errs());
457}
458
459//===----------------------------------------------------------------------===//
460// Lazily generated map to query the external variables referenced by a Block.
461//===----------------------------------------------------------------------===//
462
463namespace {
464class FindBlockDeclRefExprsVals : public StmtVisitor<FindBlockDeclRefExprsVals>{
465  BumpVector<const VarDecl*> &BEVals;
466  BumpVectorContext &BC;
467  llvm::SmallPtrSet<const VarDecl*, 4> Visited;
468  llvm::SmallPtrSet<const DeclContext*, 4> IgnoredContexts;
469public:
470  FindBlockDeclRefExprsVals(BumpVector<const VarDecl*> &bevals,
471                            BumpVectorContext &bc)
472  : BEVals(bevals), BC(bc) {}
473
474  void VisitStmt(Stmt *S) {
475    for (Stmt::child_range I = S->children(); I; ++I)
476      if (Stmt *child = *I)
477        Visit(child);
478  }
479
480  void VisitDeclRefExpr(DeclRefExpr *DR) {
481    // Non-local variables are also directly modified.
482    if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) {
483      if (!VD->hasLocalStorage()) {
484        if (Visited.insert(VD).second)
485          BEVals.push_back(VD, BC);
486      }
487    }
488  }
489
490  void VisitBlockExpr(BlockExpr *BR) {
491    // Blocks containing blocks can transitively capture more variables.
492    IgnoredContexts.insert(BR->getBlockDecl());
493    Visit(BR->getBlockDecl()->getBody());
494  }
495
496  void VisitPseudoObjectExpr(PseudoObjectExpr *PE) {
497    for (PseudoObjectExpr::semantics_iterator it = PE->semantics_begin(),
498         et = PE->semantics_end(); it != et; ++it) {
499      Expr *Semantic = *it;
500      if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic))
501        Semantic = OVE->getSourceExpr();
502      Visit(Semantic);
503    }
504  }
505};
506} // end anonymous namespace
507
508typedef BumpVector<const VarDecl*> DeclVec;
509
510static DeclVec* LazyInitializeReferencedDecls(const BlockDecl *BD,
511                                              void *&Vec,
512                                              llvm::BumpPtrAllocator &A) {
513  if (Vec)
514    return (DeclVec*) Vec;
515
516  BumpVectorContext BC(A);
517  DeclVec *BV = (DeclVec*) A.Allocate<DeclVec>();
518  new (BV) DeclVec(BC, 10);
519
520  // Go through the capture list.
521  for (const auto &CI : BD->captures()) {
522    BV->push_back(CI.getVariable(), BC);
523  }
524
525  // Find the referenced global/static variables.
526  FindBlockDeclRefExprsVals F(*BV, BC);
527  F.Visit(BD->getBody());
528
529  Vec = BV;
530  return BV;
531}
532
533std::pair<AnalysisDeclContext::referenced_decls_iterator,
534          AnalysisDeclContext::referenced_decls_iterator>
535AnalysisDeclContext::getReferencedBlockVars(const BlockDecl *BD) {
536  if (!ReferencedBlockVars)
537    ReferencedBlockVars = new llvm::DenseMap<const BlockDecl*,void*>();
538
539  DeclVec *V = LazyInitializeReferencedDecls(BD, (*ReferencedBlockVars)[BD], A);
540  return std::make_pair(V->begin(), V->end());
541}
542
543ManagedAnalysis *&AnalysisDeclContext::getAnalysisImpl(const void *tag) {
544  if (!ManagedAnalyses)
545    ManagedAnalyses = new ManagedAnalysisMap();
546  ManagedAnalysisMap *M = (ManagedAnalysisMap*) ManagedAnalyses;
547  return (*M)[tag];
548}
549
550//===----------------------------------------------------------------------===//
551// Cleanup.
552//===----------------------------------------------------------------------===//
553
554ManagedAnalysis::~ManagedAnalysis() {}
555
556AnalysisDeclContext::~AnalysisDeclContext() {
557  delete forcedBlkExprs;
558  delete ReferencedBlockVars;
559  // Release the managed analyses.
560  if (ManagedAnalyses) {
561    ManagedAnalysisMap *M = (ManagedAnalysisMap*) ManagedAnalyses;
562    llvm::DeleteContainerSeconds(*M);
563    delete M;
564  }
565}
566
567AnalysisDeclContextManager::~AnalysisDeclContextManager() {
568  llvm::DeleteContainerSeconds(Contexts);
569}
570
571LocationContext::~LocationContext() {}
572
573LocationContextManager::~LocationContextManager() {
574  clear();
575}
576
577void LocationContextManager::clear() {
578  for (llvm::FoldingSet<LocationContext>::iterator I = Contexts.begin(),
579       E = Contexts.end(); I != E; ) {
580    LocationContext *LC = &*I;
581    ++I;
582    delete LC;
583  }
584
585  Contexts.clear();
586}
587
588