AnalysisDeclContext.cpp revision d200187bd27f9ad68699693a6e57f9ee3ff260fa 
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/Decl.h"
16#include "clang/AST/DeclObjC.h"
17#include "clang/AST/DeclTemplate.h"
18#include "clang/AST/ParentMap.h"
19#include "clang/AST/StmtVisitor.h"
20#include "clang/Analysis/Analyses/LiveVariables.h"
21#include "clang/Analysis/Analyses/PseudoConstantAnalysis.h"
22#include "clang/Analysis/Analyses/CFGReachabilityAnalysis.h"
23#include "clang/Analysis/AnalysisContext.h"
24#include "clang/Analysis/CFG.h"
25#include "clang/Analysis/CFGStmtMap.h"
26#include "clang/Analysis/Support/BumpVector.h"
27#include "llvm/Support/SaveAndRestore.h"
28#include "llvm/ADT/SmallPtrSet.h"
29#include "llvm/Support/ErrorHandling.h"
30
31using namespace clang;
32
33typedef llvm::DenseMap<const void *, ManagedAnalysis *> ManagedAnalysisMap;
34
35AnalysisDeclContext::AnalysisDeclContext(AnalysisDeclContextManager *Mgr,
36                                 const Decl *d,
37                                 const CFG::BuildOptions &buildOptions)
38  : Manager(Mgr),
39    D(d),
40    cfgBuildOptions(buildOptions),
41    forcedBlkExprs(0),
42    builtCFG(false),
43    builtCompleteCFG(false),
44    ReferencedBlockVars(0),
45    ManagedAnalyses(0)
46{
47  cfgBuildOptions.forcedBlkExprs = &forcedBlkExprs;
48}
49
50AnalysisDeclContext::AnalysisDeclContext(AnalysisDeclContextManager *Mgr,
51                                 const Decl *d)
52: Manager(Mgr),
53  D(d),
54  forcedBlkExprs(0),
55  builtCFG(false),
56  builtCompleteCFG(false),
57  ReferencedBlockVars(0),
58  ManagedAnalyses(0)
59{
60  cfgBuildOptions.forcedBlkExprs = &forcedBlkExprs;
61}
62
63AnalysisDeclContextManager::AnalysisDeclContextManager(bool useUnoptimizedCFG,
64                                               bool addImplicitDtors,
65                                               bool addInitializers) {
66  cfgBuildOptions.PruneTriviallyFalseEdges = !useUnoptimizedCFG;
67  cfgBuildOptions.AddImplicitDtors = addImplicitDtors;
68  cfgBuildOptions.AddInitializers = addInitializers;
69}
70
71void AnalysisDeclContextManager::clear() {
72  for (ContextMap::iterator I = Contexts.begin(), E = Contexts.end(); I!=E; ++I)
73    delete I->second;
74  Contexts.clear();
75}
76
77Stmt *AnalysisDeclContext::getBody() const {
78  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
79    return FD->getBody();
80  else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D))
81    return MD->getBody();
82  else if (const BlockDecl *BD = dyn_cast<BlockDecl>(D))
83    return BD->getBody();
84  else if (const FunctionTemplateDecl *FunTmpl
85           = dyn_cast_or_null<FunctionTemplateDecl>(D))
86    return FunTmpl->getTemplatedDecl()->getBody();
87
88  llvm_unreachable("unknown code decl");
89}
90
91const ImplicitParamDecl *AnalysisDeclContext::getSelfDecl() const {
92  if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D))
93    return MD->getSelfDecl();
94  if (const BlockDecl *BD = dyn_cast<BlockDecl>(D)) {
95    // See if 'self' was captured by the block.
96    for (BlockDecl::capture_const_iterator it = BD->capture_begin(),
97         et = BD->capture_end(); it != et; ++it) {
98      const VarDecl *VD = it->getVariable();
99      if (VD->getName() == "self")
100        return dyn_cast<ImplicitParamDecl>(VD);
101    }
102  }
103
104  return NULL;
105}
106
107void AnalysisDeclContext::registerForcedBlockExpression(const Stmt *stmt) {
108  if (!forcedBlkExprs)
109    forcedBlkExprs = new CFG::BuildOptions::ForcedBlkExprs();
110  // Default construct an entry for 'stmt'.
111  if (const Expr *e = dyn_cast<Expr>(stmt))
112    stmt = e->IgnoreParens();
113  (void) (*forcedBlkExprs)[stmt];
114}
115
116const CFGBlock *
117AnalysisDeclContext::getBlockForRegisteredExpression(const Stmt *stmt) {
118  assert(forcedBlkExprs);
119  if (const Expr *e = dyn_cast<Expr>(stmt))
120    stmt = e->IgnoreParens();
121  CFG::BuildOptions::ForcedBlkExprs::const_iterator itr =
122    forcedBlkExprs->find(stmt);
123  assert(itr != forcedBlkExprs->end());
124  return itr->second;
125}
126
127CFG *AnalysisDeclContext::getCFG() {
128  if (!cfgBuildOptions.PruneTriviallyFalseEdges)
129    return getUnoptimizedCFG();
130
131  if (!builtCFG) {
132    cfg.reset(CFG::buildCFG(D, getBody(),
133                            &D->getASTContext(), cfgBuildOptions));
134    // Even when the cfg is not successfully built, we don't
135    // want to try building it again.
136    builtCFG = true;
137  }
138  return cfg.get();
139}
140
141CFG *AnalysisDeclContext::getUnoptimizedCFG() {
142  if (!builtCompleteCFG) {
143    SaveAndRestore<bool> NotPrune(cfgBuildOptions.PruneTriviallyFalseEdges,
144                                  false);
145    completeCFG.reset(CFG::buildCFG(D, getBody(), &D->getASTContext(),
146                                    cfgBuildOptions));
147    // Even when the cfg is not successfully built, we don't
148    // want to try building it again.
149    builtCompleteCFG = true;
150  }
151  return completeCFG.get();
152}
153
154CFGStmtMap *AnalysisDeclContext::getCFGStmtMap() {
155  if (cfgStmtMap)
156    return cfgStmtMap.get();
157
158  if (CFG *c = getCFG()) {
159    cfgStmtMap.reset(CFGStmtMap::Build(c, &getParentMap()));
160    return cfgStmtMap.get();
161  }
162
163  return 0;
164}
165
166CFGReverseBlockReachabilityAnalysis *AnalysisDeclContext::getCFGReachablityAnalysis() {
167  if (CFA)
168    return CFA.get();
169
170  if (CFG *c = getCFG()) {
171    CFA.reset(new CFGReverseBlockReachabilityAnalysis(*c));
172    return CFA.get();
173  }
174
175  return 0;
176}
177
178void AnalysisDeclContext::dumpCFG(bool ShowColors) {
179    getCFG()->dump(getASTContext().getLangOpts(), ShowColors);
180}
181
182ParentMap &AnalysisDeclContext::getParentMap() {
183  if (!PM)
184    PM.reset(new ParentMap(getBody()));
185  return *PM;
186}
187
188PseudoConstantAnalysis *AnalysisDeclContext::getPseudoConstantAnalysis() {
189  if (!PCA)
190    PCA.reset(new PseudoConstantAnalysis(getBody()));
191  return PCA.get();
192}
193
194AnalysisDeclContext *AnalysisDeclContextManager::getContext(const Decl *D) {
195  AnalysisDeclContext *&AC = Contexts[D];
196  if (!AC)
197    AC = new AnalysisDeclContext(this, D, cfgBuildOptions);
198  return AC;
199}
200
201const StackFrameContext *
202AnalysisDeclContext::getStackFrame(LocationContext const *Parent, const Stmt *S,
203                               const CFGBlock *Blk, unsigned Idx) {
204  return getLocationContextManager().getStackFrame(this, Parent, S, Blk, Idx);
205}
206
207LocationContextManager & AnalysisDeclContext::getLocationContextManager() {
208  assert(Manager &&
209         "Cannot create LocationContexts without an AnalysisDeclContextManager!");
210  return Manager->getLocationContextManager();
211}
212
213//===----------------------------------------------------------------------===//
214// FoldingSet profiling.
215//===----------------------------------------------------------------------===//
216
217void LocationContext::ProfileCommon(llvm::FoldingSetNodeID &ID,
218                                    ContextKind ck,
219                                    AnalysisDeclContext *ctx,
220                                    const LocationContext *parent,
221                                    const void *data) {
222  ID.AddInteger(ck);
223  ID.AddPointer(ctx);
224  ID.AddPointer(parent);
225  ID.AddPointer(data);
226}
227
228void StackFrameContext::Profile(llvm::FoldingSetNodeID &ID) {
229  Profile(ID, getAnalysisDeclContext(), getParent(), CallSite, Block, Index);
230}
231
232void ScopeContext::Profile(llvm::FoldingSetNodeID &ID) {
233  Profile(ID, getAnalysisDeclContext(), getParent(), Enter);
234}
235
236void BlockInvocationContext::Profile(llvm::FoldingSetNodeID &ID) {
237  Profile(ID, getAnalysisDeclContext(), getParent(), BD);
238}
239
240//===----------------------------------------------------------------------===//
241// LocationContext creation.
242//===----------------------------------------------------------------------===//
243
244template <typename LOC, typename DATA>
245const LOC*
246LocationContextManager::getLocationContext(AnalysisDeclContext *ctx,
247                                           const LocationContext *parent,
248                                           const DATA *d) {
249  llvm::FoldingSetNodeID ID;
250  LOC::Profile(ID, ctx, parent, d);
251  void *InsertPos;
252
253  LOC *L = cast_or_null<LOC>(Contexts.FindNodeOrInsertPos(ID, InsertPos));
254
255  if (!L) {
256    L = new LOC(ctx, parent, d);
257    Contexts.InsertNode(L, InsertPos);
258  }
259  return L;
260}
261
262const StackFrameContext*
263LocationContextManager::getStackFrame(AnalysisDeclContext *ctx,
264                                      const LocationContext *parent,
265                                      const Stmt *s,
266                                      const CFGBlock *blk, unsigned idx) {
267  llvm::FoldingSetNodeID ID;
268  StackFrameContext::Profile(ID, ctx, parent, s, blk, idx);
269  void *InsertPos;
270  StackFrameContext *L =
271   cast_or_null<StackFrameContext>(Contexts.FindNodeOrInsertPos(ID, InsertPos));
272  if (!L) {
273    L = new StackFrameContext(ctx, parent, s, blk, idx);
274    Contexts.InsertNode(L, InsertPos);
275  }
276  return L;
277}
278
279const ScopeContext *
280LocationContextManager::getScope(AnalysisDeclContext *ctx,
281                                 const LocationContext *parent,
282                                 const Stmt *s) {
283  return getLocationContext<ScopeContext, Stmt>(ctx, parent, s);
284}
285
286//===----------------------------------------------------------------------===//
287// LocationContext methods.
288//===----------------------------------------------------------------------===//
289
290const StackFrameContext *LocationContext::getCurrentStackFrame() const {
291  const LocationContext *LC = this;
292  while (LC) {
293    if (const StackFrameContext *SFC = dyn_cast<StackFrameContext>(LC))
294      return SFC;
295    LC = LC->getParent();
296  }
297  return NULL;
298}
299
300const StackFrameContext *
301LocationContext::getStackFrameForDeclContext(const DeclContext *DC) const {
302  const LocationContext *LC = this;
303  while (LC) {
304    if (const StackFrameContext *SFC = dyn_cast<StackFrameContext>(LC)) {
305      if (cast<DeclContext>(SFC->getDecl()) == DC)
306        return SFC;
307    }
308    LC = LC->getParent();
309  }
310  return NULL;
311}
312
313bool LocationContext::isParentOf(const LocationContext *LC) const {
314  do {
315    const LocationContext *Parent = LC->getParent();
316    if (Parent == this)
317      return true;
318    else
319      LC = Parent;
320  } while (LC);
321
322  return false;
323}
324
325//===----------------------------------------------------------------------===//
326// Lazily generated map to query the external variables referenced by a Block.
327//===----------------------------------------------------------------------===//
328
329namespace {
330class FindBlockDeclRefExprsVals : public StmtVisitor<FindBlockDeclRefExprsVals>{
331  BumpVector<const VarDecl*> &BEVals;
332  BumpVectorContext &BC;
333  llvm::SmallPtrSet<const VarDecl*, 4> Visited;
334  llvm::SmallPtrSet<const DeclContext*, 4> IgnoredContexts;
335public:
336  FindBlockDeclRefExprsVals(BumpVector<const VarDecl*> &bevals,
337                            BumpVectorContext &bc)
338  : BEVals(bevals), BC(bc) {}
339
340  bool IsTrackedDecl(const VarDecl *VD) {
341    const DeclContext *DC = VD->getDeclContext();
342    return IgnoredContexts.count(DC) == 0;
343  }
344
345  void VisitStmt(Stmt *S) {
346    for (Stmt::child_range I = S->children(); I; ++I)
347      if (Stmt *child = *I)
348        Visit(child);
349  }
350
351  void VisitDeclRefExpr(DeclRefExpr *DR) {
352    // Non-local variables are also directly modified.
353    if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) {
354      if (!VD->hasLocalStorage()) {
355        if (Visited.insert(VD))
356          BEVals.push_back(VD, BC);
357      } else if (DR->refersToEnclosingLocal()) {
358        if (Visited.insert(VD) && IsTrackedDecl(VD))
359          BEVals.push_back(VD, BC);
360      }
361    }
362  }
363
364  void VisitBlockExpr(BlockExpr *BR) {
365    // Blocks containing blocks can transitively capture more variables.
366    IgnoredContexts.insert(BR->getBlockDecl());
367    Visit(BR->getBlockDecl()->getBody());
368  }
369
370  void VisitPseudoObjectExpr(PseudoObjectExpr *PE) {
371    for (PseudoObjectExpr::semantics_iterator it = PE->semantics_begin(),
372         et = PE->semantics_end(); it != et; ++it) {
373      Expr *Semantic = *it;
374      if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic))
375        Semantic = OVE->getSourceExpr();
376      Visit(Semantic);
377    }
378  }
379};
380} // end anonymous namespace
381
382typedef BumpVector<const VarDecl*> DeclVec;
383
384static DeclVec* LazyInitializeReferencedDecls(const BlockDecl *BD,
385                                              void *&Vec,
386                                              llvm::BumpPtrAllocator &A) {
387  if (Vec)
388    return (DeclVec*) Vec;
389
390  BumpVectorContext BC(A);
391  DeclVec *BV = (DeclVec*) A.Allocate<DeclVec>();
392  new (BV) DeclVec(BC, 10);
393
394  // Find the referenced variables.
395  FindBlockDeclRefExprsVals F(*BV, BC);
396  F.Visit(BD->getBody());
397
398  Vec = BV;
399  return BV;
400}
401
402std::pair<AnalysisDeclContext::referenced_decls_iterator,
403          AnalysisDeclContext::referenced_decls_iterator>
404AnalysisDeclContext::getReferencedBlockVars(const BlockDecl *BD) {
405  if (!ReferencedBlockVars)
406    ReferencedBlockVars = new llvm::DenseMap<const BlockDecl*,void*>();
407
408  DeclVec *V = LazyInitializeReferencedDecls(BD, (*ReferencedBlockVars)[BD], A);
409  return std::make_pair(V->begin(), V->end());
410}
411
412ManagedAnalysis *&AnalysisDeclContext::getAnalysisImpl(const void *tag) {
413  if (!ManagedAnalyses)
414    ManagedAnalyses = new ManagedAnalysisMap();
415  ManagedAnalysisMap *M = (ManagedAnalysisMap*) ManagedAnalyses;
416  return (*M)[tag];
417}
418
419//===----------------------------------------------------------------------===//
420// Cleanup.
421//===----------------------------------------------------------------------===//
422
423ManagedAnalysis::~ManagedAnalysis() {}
424
425AnalysisDeclContext::~AnalysisDeclContext() {
426  delete forcedBlkExprs;
427  delete ReferencedBlockVars;
428  // Release the managed analyses.
429  if (ManagedAnalyses) {
430    ManagedAnalysisMap *M = (ManagedAnalysisMap*) ManagedAnalyses;
431    for (ManagedAnalysisMap::iterator I = M->begin(), E = M->end(); I!=E; ++I)
432      delete I->second;
433    delete M;
434  }
435}
436
437AnalysisDeclContextManager::~AnalysisDeclContextManager() {
438  for (ContextMap::iterator I = Contexts.begin(), E = Contexts.end(); I!=E; ++I)
439    delete I->second;
440}
441
442LocationContext::~LocationContext() {}
443
444LocationContextManager::~LocationContextManager() {
445  clear();
446}
447
448void LocationContextManager::clear() {
449  for (llvm::FoldingSet<LocationContext>::iterator I = Contexts.begin(),
450       E = Contexts.end(); I != E; ) {
451    LocationContext *LC = &*I;
452    ++I;
453    delete LC;
454  }
455
456  Contexts.clear();
457}
458
459