AnalysisDeclContext.cpp revision 239462 
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
32using namespace clang;
33
34typedef llvm::DenseMap<const void *, ManagedAnalysis *> ManagedAnalysisMap;
35
36AnalysisDeclContext::AnalysisDeclContext(AnalysisDeclContextManager *Mgr,
37                                 const Decl *d,
38                                 const CFG::BuildOptions &buildOptions)
39  : Manager(Mgr),
40    D(d),
41    cfgBuildOptions(buildOptions),
42    forcedBlkExprs(0),
43    builtCFG(false),
44    builtCompleteCFG(false),
45    ReferencedBlockVars(0),
46    ManagedAnalyses(0)
47{
48  cfgBuildOptions.forcedBlkExprs = &forcedBlkExprs;
49}
50
51AnalysisDeclContext::AnalysisDeclContext(AnalysisDeclContextManager *Mgr,
52                                 const Decl *d)
53: Manager(Mgr),
54  D(d),
55  forcedBlkExprs(0),
56  builtCFG(false),
57  builtCompleteCFG(false),
58  ReferencedBlockVars(0),
59  ManagedAnalyses(0)
60{
61  cfgBuildOptions.forcedBlkExprs = &forcedBlkExprs;
62}
63
64AnalysisDeclContextManager::AnalysisDeclContextManager(bool useUnoptimizedCFG,
65                                               bool addImplicitDtors,
66                                               bool addInitializers) {
67  cfgBuildOptions.PruneTriviallyFalseEdges = !useUnoptimizedCFG;
68  cfgBuildOptions.AddImplicitDtors = addImplicitDtors;
69  cfgBuildOptions.AddInitializers = addInitializers;
70}
71
72void AnalysisDeclContextManager::clear() {
73  for (ContextMap::iterator I = Contexts.begin(), E = Contexts.end(); I!=E; ++I)
74    delete I->second;
75  Contexts.clear();
76}
77
78Stmt *AnalysisDeclContext::getBody() const {
79  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
80    return FD->getBody();
81  else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D))
82    return MD->getBody();
83  else if (const BlockDecl *BD = dyn_cast<BlockDecl>(D))
84    return BD->getBody();
85  else if (const FunctionTemplateDecl *FunTmpl
86           = dyn_cast_or_null<FunctionTemplateDecl>(D))
87    return FunTmpl->getTemplatedDecl()->getBody();
88
89  llvm_unreachable("unknown code decl");
90}
91
92const ImplicitParamDecl *AnalysisDeclContext::getSelfDecl() const {
93  if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D))
94    return MD->getSelfDecl();
95  if (const BlockDecl *BD = dyn_cast<BlockDecl>(D)) {
96    // See if 'self' was captured by the block.
97    for (BlockDecl::capture_const_iterator it = BD->capture_begin(),
98         et = BD->capture_end(); it != et; ++it) {
99      const VarDecl *VD = it->getVariable();
100      if (VD->getName() == "self")
101        return dyn_cast<ImplicitParamDecl>(VD);
102    }
103  }
104
105  return NULL;
106}
107
108void AnalysisDeclContext::registerForcedBlockExpression(const Stmt *stmt) {
109  if (!forcedBlkExprs)
110    forcedBlkExprs = new CFG::BuildOptions::ForcedBlkExprs();
111  // Default construct an entry for 'stmt'.
112  if (const Expr *e = dyn_cast<Expr>(stmt))
113    stmt = e->IgnoreParens();
114  (void) (*forcedBlkExprs)[stmt];
115}
116
117const CFGBlock *
118AnalysisDeclContext::getBlockForRegisteredExpression(const Stmt *stmt) {
119  assert(forcedBlkExprs);
120  if (const Expr *e = dyn_cast<Expr>(stmt))
121    stmt = e->IgnoreParens();
122  CFG::BuildOptions::ForcedBlkExprs::const_iterator itr =
123    forcedBlkExprs->find(stmt);
124  assert(itr != forcedBlkExprs->end());
125  return itr->second;
126}
127
128CFG *AnalysisDeclContext::getCFG() {
129  if (!cfgBuildOptions.PruneTriviallyFalseEdges)
130    return getUnoptimizedCFG();
131
132  if (!builtCFG) {
133    cfg.reset(CFG::buildCFG(D, getBody(),
134                            &D->getASTContext(), cfgBuildOptions));
135    // Even when the cfg is not successfully built, we don't
136    // want to try building it again.
137    builtCFG = true;
138  }
139  return cfg.get();
140}
141
142CFG *AnalysisDeclContext::getUnoptimizedCFG() {
143  if (!builtCompleteCFG) {
144    SaveAndRestore<bool> NotPrune(cfgBuildOptions.PruneTriviallyFalseEdges,
145                                  false);
146    completeCFG.reset(CFG::buildCFG(D, getBody(), &D->getASTContext(),
147                                    cfgBuildOptions));
148    // Even when the cfg is not successfully built, we don't
149    // want to try building it again.
150    builtCompleteCFG = true;
151  }
152  return completeCFG.get();
153}
154
155CFGStmtMap *AnalysisDeclContext::getCFGStmtMap() {
156  if (cfgStmtMap)
157    return cfgStmtMap.get();
158
159  if (CFG *c = getCFG()) {
160    cfgStmtMap.reset(CFGStmtMap::Build(c, &getParentMap()));
161    return cfgStmtMap.get();
162  }
163
164  return 0;
165}
166
167CFGReverseBlockReachabilityAnalysis *AnalysisDeclContext::getCFGReachablityAnalysis() {
168  if (CFA)
169    return CFA.get();
170
171  if (CFG *c = getCFG()) {
172    CFA.reset(new CFGReverseBlockReachabilityAnalysis(*c));
173    return CFA.get();
174  }
175
176  return 0;
177}
178
179void AnalysisDeclContext::dumpCFG(bool ShowColors) {
180    getCFG()->dump(getASTContext().getLangOpts(), ShowColors);
181}
182
183ParentMap &AnalysisDeclContext::getParentMap() {
184  if (!PM) {
185    PM.reset(new ParentMap(getBody()));
186    if (const CXXConstructorDecl *C = dyn_cast<CXXConstructorDecl>(getDecl())) {
187      for (CXXConstructorDecl::init_const_iterator I = C->init_begin(),
188                                                   E = C->init_end();
189           I != E; ++I) {
190        PM->addStmt((*I)->getInit());
191      }
192    }
193  }
194  return *PM;
195}
196
197PseudoConstantAnalysis *AnalysisDeclContext::getPseudoConstantAnalysis() {
198  if (!PCA)
199    PCA.reset(new PseudoConstantAnalysis(getBody()));
200  return PCA.get();
201}
202
203AnalysisDeclContext *AnalysisDeclContextManager::getContext(const Decl *D) {
204  AnalysisDeclContext *&AC = Contexts[D];
205  if (!AC)
206    AC = new AnalysisDeclContext(this, D, cfgBuildOptions);
207  return AC;
208}
209
210const StackFrameContext *
211AnalysisDeclContext::getStackFrame(LocationContext const *Parent, const Stmt *S,
212                               const CFGBlock *Blk, unsigned Idx) {
213  return getLocationContextManager().getStackFrame(this, Parent, S, Blk, Idx);
214}
215
216const BlockInvocationContext *
217AnalysisDeclContext::getBlockInvocationContext(const LocationContext *parent,
218                                               const clang::BlockDecl *BD,
219                                               const void *ContextData) {
220  return getLocationContextManager().getBlockInvocationContext(this, parent,
221                                                               BD, ContextData);
222}
223
224LocationContextManager & AnalysisDeclContext::getLocationContextManager() {
225  assert(Manager &&
226         "Cannot create LocationContexts without an AnalysisDeclContextManager!");
227  return Manager->getLocationContextManager();
228}
229
230//===----------------------------------------------------------------------===//
231// FoldingSet profiling.
232//===----------------------------------------------------------------------===//
233
234void LocationContext::ProfileCommon(llvm::FoldingSetNodeID &ID,
235                                    ContextKind ck,
236                                    AnalysisDeclContext *ctx,
237                                    const LocationContext *parent,
238                                    const void *data) {
239  ID.AddInteger(ck);
240  ID.AddPointer(ctx);
241  ID.AddPointer(parent);
242  ID.AddPointer(data);
243}
244
245void StackFrameContext::Profile(llvm::FoldingSetNodeID &ID) {
246  Profile(ID, getAnalysisDeclContext(), getParent(), CallSite, Block, Index);
247}
248
249void ScopeContext::Profile(llvm::FoldingSetNodeID &ID) {
250  Profile(ID, getAnalysisDeclContext(), getParent(), Enter);
251}
252
253void BlockInvocationContext::Profile(llvm::FoldingSetNodeID &ID) {
254  Profile(ID, getAnalysisDeclContext(), getParent(), BD, ContextData);
255}
256
257//===----------------------------------------------------------------------===//
258// LocationContext creation.
259//===----------------------------------------------------------------------===//
260
261template <typename LOC, typename DATA>
262const LOC*
263LocationContextManager::getLocationContext(AnalysisDeclContext *ctx,
264                                           const LocationContext *parent,
265                                           const DATA *d) {
266  llvm::FoldingSetNodeID ID;
267  LOC::Profile(ID, ctx, parent, d);
268  void *InsertPos;
269
270  LOC *L = cast_or_null<LOC>(Contexts.FindNodeOrInsertPos(ID, InsertPos));
271
272  if (!L) {
273    L = new LOC(ctx, parent, d);
274    Contexts.InsertNode(L, InsertPos);
275  }
276  return L;
277}
278
279const StackFrameContext*
280LocationContextManager::getStackFrame(AnalysisDeclContext *ctx,
281                                      const LocationContext *parent,
282                                      const Stmt *s,
283                                      const CFGBlock *blk, unsigned idx) {
284  llvm::FoldingSetNodeID ID;
285  StackFrameContext::Profile(ID, ctx, parent, s, blk, idx);
286  void *InsertPos;
287  StackFrameContext *L =
288   cast_or_null<StackFrameContext>(Contexts.FindNodeOrInsertPos(ID, InsertPos));
289  if (!L) {
290    L = new StackFrameContext(ctx, parent, s, blk, idx);
291    Contexts.InsertNode(L, InsertPos);
292  }
293  return L;
294}
295
296const ScopeContext *
297LocationContextManager::getScope(AnalysisDeclContext *ctx,
298                                 const LocationContext *parent,
299                                 const Stmt *s) {
300  return getLocationContext<ScopeContext, Stmt>(ctx, parent, s);
301}
302
303const BlockInvocationContext *
304LocationContextManager::getBlockInvocationContext(AnalysisDeclContext *ctx,
305                                                  const LocationContext *parent,
306                                                  const BlockDecl *BD,
307                                                  const void *ContextData) {
308  llvm::FoldingSetNodeID ID;
309  BlockInvocationContext::Profile(ID, ctx, parent, BD, ContextData);
310  void *InsertPos;
311  BlockInvocationContext *L =
312    cast_or_null<BlockInvocationContext>(Contexts.FindNodeOrInsertPos(ID,
313                                                                    InsertPos));
314  if (!L) {
315    L = new BlockInvocationContext(ctx, parent, BD, ContextData);
316    Contexts.InsertNode(L, InsertPos);
317  }
318  return L;
319}
320
321//===----------------------------------------------------------------------===//
322// LocationContext methods.
323//===----------------------------------------------------------------------===//
324
325const StackFrameContext *LocationContext::getCurrentStackFrame() const {
326  const LocationContext *LC = this;
327  while (LC) {
328    if (const StackFrameContext *SFC = dyn_cast<StackFrameContext>(LC))
329      return SFC;
330    LC = LC->getParent();
331  }
332  return NULL;
333}
334
335bool LocationContext::isParentOf(const LocationContext *LC) const {
336  do {
337    const LocationContext *Parent = LC->getParent();
338    if (Parent == this)
339      return true;
340    else
341      LC = Parent;
342  } while (LC);
343
344  return false;
345}
346
347//===----------------------------------------------------------------------===//
348// Lazily generated map to query the external variables referenced by a Block.
349//===----------------------------------------------------------------------===//
350
351namespace {
352class FindBlockDeclRefExprsVals : public StmtVisitor<FindBlockDeclRefExprsVals>{
353  BumpVector<const VarDecl*> &BEVals;
354  BumpVectorContext &BC;
355  llvm::SmallPtrSet<const VarDecl*, 4> Visited;
356  llvm::SmallPtrSet<const DeclContext*, 4> IgnoredContexts;
357public:
358  FindBlockDeclRefExprsVals(BumpVector<const VarDecl*> &bevals,
359                            BumpVectorContext &bc)
360  : BEVals(bevals), BC(bc) {}
361
362  bool IsTrackedDecl(const VarDecl *VD) {
363    const DeclContext *DC = VD->getDeclContext();
364    return IgnoredContexts.count(DC) == 0;
365  }
366
367  void VisitStmt(Stmt *S) {
368    for (Stmt::child_range I = S->children(); I; ++I)
369      if (Stmt *child = *I)
370        Visit(child);
371  }
372
373  void VisitDeclRefExpr(DeclRefExpr *DR) {
374    // Non-local variables are also directly modified.
375    if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) {
376      if (!VD->hasLocalStorage()) {
377        if (Visited.insert(VD))
378          BEVals.push_back(VD, BC);
379      } else if (DR->refersToEnclosingLocal()) {
380        if (Visited.insert(VD) && IsTrackedDecl(VD))
381          BEVals.push_back(VD, BC);
382      }
383    }
384  }
385
386  void VisitBlockExpr(BlockExpr *BR) {
387    // Blocks containing blocks can transitively capture more variables.
388    IgnoredContexts.insert(BR->getBlockDecl());
389    Visit(BR->getBlockDecl()->getBody());
390  }
391
392  void VisitPseudoObjectExpr(PseudoObjectExpr *PE) {
393    for (PseudoObjectExpr::semantics_iterator it = PE->semantics_begin(),
394         et = PE->semantics_end(); it != et; ++it) {
395      Expr *Semantic = *it;
396      if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic))
397        Semantic = OVE->getSourceExpr();
398      Visit(Semantic);
399    }
400  }
401};
402} // end anonymous namespace
403
404typedef BumpVector<const VarDecl*> DeclVec;
405
406static DeclVec* LazyInitializeReferencedDecls(const BlockDecl *BD,
407                                              void *&Vec,
408                                              llvm::BumpPtrAllocator &A) {
409  if (Vec)
410    return (DeclVec*) Vec;
411
412  BumpVectorContext BC(A);
413  DeclVec *BV = (DeclVec*) A.Allocate<DeclVec>();
414  new (BV) DeclVec(BC, 10);
415
416  // Find the referenced variables.
417  FindBlockDeclRefExprsVals F(*BV, BC);
418  F.Visit(BD->getBody());
419
420  Vec = BV;
421  return BV;
422}
423
424std::pair<AnalysisDeclContext::referenced_decls_iterator,
425          AnalysisDeclContext::referenced_decls_iterator>
426AnalysisDeclContext::getReferencedBlockVars(const BlockDecl *BD) {
427  if (!ReferencedBlockVars)
428    ReferencedBlockVars = new llvm::DenseMap<const BlockDecl*,void*>();
429
430  DeclVec *V = LazyInitializeReferencedDecls(BD, (*ReferencedBlockVars)[BD], A);
431  return std::make_pair(V->begin(), V->end());
432}
433
434ManagedAnalysis *&AnalysisDeclContext::getAnalysisImpl(const void *tag) {
435  if (!ManagedAnalyses)
436    ManagedAnalyses = new ManagedAnalysisMap();
437  ManagedAnalysisMap *M = (ManagedAnalysisMap*) ManagedAnalyses;
438  return (*M)[tag];
439}
440
441//===----------------------------------------------------------------------===//
442// Cleanup.
443//===----------------------------------------------------------------------===//
444
445ManagedAnalysis::~ManagedAnalysis() {}
446
447AnalysisDeclContext::~AnalysisDeclContext() {
448  delete forcedBlkExprs;
449  delete ReferencedBlockVars;
450  // Release the managed analyses.
451  if (ManagedAnalyses) {
452    ManagedAnalysisMap *M = (ManagedAnalysisMap*) ManagedAnalyses;
453    for (ManagedAnalysisMap::iterator I = M->begin(), E = M->end(); I!=E; ++I)
454      delete I->second;
455    delete M;
456  }
457}
458
459AnalysisDeclContextManager::~AnalysisDeclContextManager() {
460  for (ContextMap::iterator I = Contexts.begin(), E = Contexts.end(); I!=E; ++I)
461    delete I->second;
462}
463
464LocationContext::~LocationContext() {}
465
466LocationContextManager::~LocationContextManager() {
467  clear();
468}
469
470void LocationContextManager::clear() {
471  for (llvm::FoldingSet<LocationContext>::iterator I = Contexts.begin(),
472       E = Contexts.end(); I != E; ) {
473    LocationContext *LC = &*I;
474    ++I;
475    delete LC;
476  }
477
478  Contexts.clear();
479}
480
481