AnalysisDeclContext.cpp revision f4b88a45902af1802a1cb42ba48b1c474474f228 
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/SmallSet.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                                 idx::TranslationUnit *tu,
38                                 const CFG::BuildOptions &buildOptions)
39  : Manager(Mgr),
40    D(d),
41    TU(tu),
42    cfgBuildOptions(buildOptions),
43    forcedBlkExprs(0),
44    builtCFG(false),
45    builtCompleteCFG(false),
46    ReferencedBlockVars(0),
47    ManagedAnalyses(0)
48{
49  cfgBuildOptions.forcedBlkExprs = &forcedBlkExprs;
50}
51
52AnalysisDeclContext::AnalysisDeclContext(AnalysisDeclContextManager *Mgr,
53                                 const Decl *d,
54                                 idx::TranslationUnit *tu)
55: Manager(Mgr),
56  D(d),
57  TU(tu),
58  forcedBlkExprs(0),
59  builtCFG(false),
60  builtCompleteCFG(false),
61  ReferencedBlockVars(0),
62  ManagedAnalyses(0)
63{
64  cfgBuildOptions.forcedBlkExprs = &forcedBlkExprs;
65}
66
67AnalysisDeclContextManager::AnalysisDeclContextManager(bool useUnoptimizedCFG,
68                                               bool addImplicitDtors,
69                                               bool addInitializers) {
70  cfgBuildOptions.PruneTriviallyFalseEdges = !useUnoptimizedCFG;
71  cfgBuildOptions.AddImplicitDtors = addImplicitDtors;
72  cfgBuildOptions.AddInitializers = addInitializers;
73}
74
75void AnalysisDeclContextManager::clear() {
76  for (ContextMap::iterator I = Contexts.begin(), E = Contexts.end(); I!=E; ++I)
77    delete I->second;
78  Contexts.clear();
79}
80
81Stmt *AnalysisDeclContext::getBody() const {
82  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
83    return FD->getBody();
84  else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D))
85    return MD->getBody();
86  else if (const BlockDecl *BD = dyn_cast<BlockDecl>(D))
87    return BD->getBody();
88  else if (const FunctionTemplateDecl *FunTmpl
89           = dyn_cast_or_null<FunctionTemplateDecl>(D))
90    return FunTmpl->getTemplatedDecl()->getBody();
91
92  llvm_unreachable("unknown code decl");
93}
94
95const ImplicitParamDecl *AnalysisDeclContext::getSelfDecl() const {
96  if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D))
97    return MD->getSelfDecl();
98  if (const BlockDecl *BD = dyn_cast<BlockDecl>(D)) {
99    // See if 'self' was captured by the block.
100    for (BlockDecl::capture_const_iterator it = BD->capture_begin(),
101         et = BD->capture_end(); it != et; ++it) {
102      const VarDecl *VD = it->getVariable();
103      if (VD->getName() == "self")
104        return dyn_cast<ImplicitParamDecl>(VD);
105    }
106  }
107
108  return NULL;
109}
110
111void AnalysisDeclContext::registerForcedBlockExpression(const Stmt *stmt) {
112  if (!forcedBlkExprs)
113    forcedBlkExprs = new CFG::BuildOptions::ForcedBlkExprs();
114  // Default construct an entry for 'stmt'.
115  if (const Expr *e = dyn_cast<Expr>(stmt))
116    stmt = e->IgnoreParens();
117  (void) (*forcedBlkExprs)[stmt];
118}
119
120const CFGBlock *
121AnalysisDeclContext::getBlockForRegisteredExpression(const Stmt *stmt) {
122  assert(forcedBlkExprs);
123  if (const Expr *e = dyn_cast<Expr>(stmt))
124    stmt = e->IgnoreParens();
125  CFG::BuildOptions::ForcedBlkExprs::const_iterator itr =
126    forcedBlkExprs->find(stmt);
127  assert(itr != forcedBlkExprs->end());
128  return itr->second;
129}
130
131CFG *AnalysisDeclContext::getCFG() {
132  if (!cfgBuildOptions.PruneTriviallyFalseEdges)
133    return getUnoptimizedCFG();
134
135  if (!builtCFG) {
136    cfg.reset(CFG::buildCFG(D, getBody(),
137                            &D->getASTContext(), cfgBuildOptions));
138    // Even when the cfg is not successfully built, we don't
139    // want to try building it again.
140    builtCFG = true;
141  }
142  return cfg.get();
143}
144
145CFG *AnalysisDeclContext::getUnoptimizedCFG() {
146  if (!builtCompleteCFG) {
147    SaveAndRestore<bool> NotPrune(cfgBuildOptions.PruneTriviallyFalseEdges,
148                                  false);
149    completeCFG.reset(CFG::buildCFG(D, getBody(), &D->getASTContext(),
150                                    cfgBuildOptions));
151    // Even when the cfg is not successfully built, we don't
152    // want to try building it again.
153    builtCompleteCFG = true;
154  }
155  return completeCFG.get();
156}
157
158CFGStmtMap *AnalysisDeclContext::getCFGStmtMap() {
159  if (cfgStmtMap)
160    return cfgStmtMap.get();
161
162  if (CFG *c = getCFG()) {
163    cfgStmtMap.reset(CFGStmtMap::Build(c, &getParentMap()));
164    return cfgStmtMap.get();
165  }
166
167  return 0;
168}
169
170CFGReverseBlockReachabilityAnalysis *AnalysisDeclContext::getCFGReachablityAnalysis() {
171  if (CFA)
172    return CFA.get();
173
174  if (CFG *c = getCFG()) {
175    CFA.reset(new CFGReverseBlockReachabilityAnalysis(*c));
176    return CFA.get();
177  }
178
179  return 0;
180}
181
182void AnalysisDeclContext::dumpCFG(bool ShowColors) {
183    getCFG()->dump(getASTContext().getLangOptions(), ShowColors);
184}
185
186ParentMap &AnalysisDeclContext::getParentMap() {
187  if (!PM)
188    PM.reset(new ParentMap(getBody()));
189  return *PM;
190}
191
192PseudoConstantAnalysis *AnalysisDeclContext::getPseudoConstantAnalysis() {
193  if (!PCA)
194    PCA.reset(new PseudoConstantAnalysis(getBody()));
195  return PCA.get();
196}
197
198AnalysisDeclContext *AnalysisDeclContextManager::getContext(const Decl *D,
199                                                    idx::TranslationUnit *TU) {
200  AnalysisDeclContext *&AC = Contexts[D];
201  if (!AC)
202    AC = new AnalysisDeclContext(this, D, TU, cfgBuildOptions);
203  return AC;
204}
205
206const StackFrameContext *
207AnalysisDeclContext::getStackFrame(LocationContext const *Parent, const Stmt *S,
208                               const CFGBlock *Blk, unsigned Idx) {
209  return getLocationContextManager().getStackFrame(this, Parent, S, Blk, Idx);
210}
211
212LocationContextManager & AnalysisDeclContext::getLocationContextManager() {
213  assert(Manager &&
214         "Cannot create LocationContexts without an AnalysisDeclContextManager!");
215  return Manager->getLocationContextManager();
216}
217
218//===----------------------------------------------------------------------===//
219// FoldingSet profiling.
220//===----------------------------------------------------------------------===//
221
222void LocationContext::ProfileCommon(llvm::FoldingSetNodeID &ID,
223                                    ContextKind ck,
224                                    AnalysisDeclContext *ctx,
225                                    const LocationContext *parent,
226                                    const void *data) {
227  ID.AddInteger(ck);
228  ID.AddPointer(ctx);
229  ID.AddPointer(parent);
230  ID.AddPointer(data);
231}
232
233void StackFrameContext::Profile(llvm::FoldingSetNodeID &ID) {
234  Profile(ID, getAnalysisDeclContext(), getParent(), CallSite, Block, Index);
235}
236
237void ScopeContext::Profile(llvm::FoldingSetNodeID &ID) {
238  Profile(ID, getAnalysisDeclContext(), getParent(), Enter);
239}
240
241void BlockInvocationContext::Profile(llvm::FoldingSetNodeID &ID) {
242  Profile(ID, getAnalysisDeclContext(), getParent(), BD);
243}
244
245//===----------------------------------------------------------------------===//
246// LocationContext creation.
247//===----------------------------------------------------------------------===//
248
249template <typename LOC, typename DATA>
250const LOC*
251LocationContextManager::getLocationContext(AnalysisDeclContext *ctx,
252                                           const LocationContext *parent,
253                                           const DATA *d) {
254  llvm::FoldingSetNodeID ID;
255  LOC::Profile(ID, ctx, parent, d);
256  void *InsertPos;
257
258  LOC *L = cast_or_null<LOC>(Contexts.FindNodeOrInsertPos(ID, InsertPos));
259
260  if (!L) {
261    L = new LOC(ctx, parent, d);
262    Contexts.InsertNode(L, InsertPos);
263  }
264  return L;
265}
266
267const StackFrameContext*
268LocationContextManager::getStackFrame(AnalysisDeclContext *ctx,
269                                      const LocationContext *parent,
270                                      const Stmt *s,
271                                      const CFGBlock *blk, unsigned idx) {
272  llvm::FoldingSetNodeID ID;
273  StackFrameContext::Profile(ID, ctx, parent, s, blk, idx);
274  void *InsertPos;
275  StackFrameContext *L =
276   cast_or_null<StackFrameContext>(Contexts.FindNodeOrInsertPos(ID, InsertPos));
277  if (!L) {
278    L = new StackFrameContext(ctx, parent, s, blk, idx);
279    Contexts.InsertNode(L, InsertPos);
280  }
281  return L;
282}
283
284const ScopeContext *
285LocationContextManager::getScope(AnalysisDeclContext *ctx,
286                                 const LocationContext *parent,
287                                 const Stmt *s) {
288  return getLocationContext<ScopeContext, Stmt>(ctx, parent, s);
289}
290
291//===----------------------------------------------------------------------===//
292// LocationContext methods.
293//===----------------------------------------------------------------------===//
294
295const StackFrameContext *LocationContext::getCurrentStackFrame() const {
296  const LocationContext *LC = this;
297  while (LC) {
298    if (const StackFrameContext *SFC = dyn_cast<StackFrameContext>(LC))
299      return SFC;
300    LC = LC->getParent();
301  }
302  return NULL;
303}
304
305const StackFrameContext *
306LocationContext::getStackFrameForDeclContext(const DeclContext *DC) const {
307  const LocationContext *LC = this;
308  while (LC) {
309    if (const StackFrameContext *SFC = dyn_cast<StackFrameContext>(LC)) {
310      if (cast<DeclContext>(SFC->getDecl()) == DC)
311        return SFC;
312    }
313    LC = LC->getParent();
314  }
315  return NULL;
316}
317
318bool LocationContext::isParentOf(const LocationContext *LC) const {
319  do {
320    const LocationContext *Parent = LC->getParent();
321    if (Parent == this)
322      return true;
323    else
324      LC = Parent;
325  } while (LC);
326
327  return false;
328}
329
330//===----------------------------------------------------------------------===//
331// Lazily generated map to query the external variables referenced by a Block.
332//===----------------------------------------------------------------------===//
333
334namespace {
335class FindBlockDeclRefExprsVals : public StmtVisitor<FindBlockDeclRefExprsVals>{
336  BumpVector<const VarDecl*> &BEVals;
337  BumpVectorContext &BC;
338  llvm::DenseMap<const VarDecl*, unsigned> Visited;
339  llvm::SmallSet<const DeclContext*, 4> IgnoredContexts;
340public:
341  FindBlockDeclRefExprsVals(BumpVector<const VarDecl*> &bevals,
342                            BumpVectorContext &bc)
343  : BEVals(bevals), BC(bc) {}
344
345  bool IsTrackedDecl(const VarDecl *VD) {
346    const DeclContext *DC = VD->getDeclContext();
347    return IgnoredContexts.count(DC) == 0;
348  }
349
350  void VisitStmt(Stmt *S) {
351    for (Stmt::child_range I = S->children(); I; ++I)
352      if (Stmt *child = *I)
353        Visit(child);
354  }
355
356  void VisitDeclRefExpr(DeclRefExpr *DR) {
357    // Non-local variables are also directly modified.
358    if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()))
359      if (!VD->hasLocalStorage()) {
360        unsigned &flag = Visited[VD];
361        if (!flag) {
362          flag = 1;
363          BEVals.push_back(VD, BC);
364        }
365      } else if (DR->refersToEnclosingLocal()) {
366        unsigned &flag = Visited[VD];
367        if (!flag) {
368          flag = 1;
369          if (IsTrackedDecl(VD))
370            BEVals.push_back(VD, BC);
371        }
372      }
373  }
374
375  void VisitBlockExpr(BlockExpr *BR) {
376    // Blocks containing blocks can transitively capture more variables.
377    IgnoredContexts.insert(BR->getBlockDecl());
378    Visit(BR->getBlockDecl()->getBody());
379  }
380
381  void VisitPseudoObjectExpr(PseudoObjectExpr *PE) {
382    for (PseudoObjectExpr::semantics_iterator it = PE->semantics_begin(),
383         et = PE->semantics_end(); it != et; ++it) {
384      Expr *Semantic = *it;
385      if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic))
386        Semantic = OVE->getSourceExpr();
387      Visit(Semantic);
388    }
389  }
390};
391} // end anonymous namespace
392
393typedef BumpVector<const VarDecl*> DeclVec;
394
395static DeclVec* LazyInitializeReferencedDecls(const BlockDecl *BD,
396                                              void *&Vec,
397                                              llvm::BumpPtrAllocator &A) {
398  if (Vec)
399    return (DeclVec*) Vec;
400
401  BumpVectorContext BC(A);
402  DeclVec *BV = (DeclVec*) A.Allocate<DeclVec>();
403  new (BV) DeclVec(BC, 10);
404
405  // Find the referenced variables.
406  FindBlockDeclRefExprsVals F(*BV, BC);
407  F.Visit(BD->getBody());
408
409  Vec = BV;
410  return BV;
411}
412
413std::pair<AnalysisDeclContext::referenced_decls_iterator,
414          AnalysisDeclContext::referenced_decls_iterator>
415AnalysisDeclContext::getReferencedBlockVars(const BlockDecl *BD) {
416  if (!ReferencedBlockVars)
417    ReferencedBlockVars = new llvm::DenseMap<const BlockDecl*,void*>();
418
419  DeclVec *V = LazyInitializeReferencedDecls(BD, (*ReferencedBlockVars)[BD], A);
420  return std::make_pair(V->begin(), V->end());
421}
422
423ManagedAnalysis *&AnalysisDeclContext::getAnalysisImpl(const void *tag) {
424  if (!ManagedAnalyses)
425    ManagedAnalyses = new ManagedAnalysisMap();
426  ManagedAnalysisMap *M = (ManagedAnalysisMap*) ManagedAnalyses;
427  return (*M)[tag];
428}
429
430//===----------------------------------------------------------------------===//
431// Cleanup.
432//===----------------------------------------------------------------------===//
433
434ManagedAnalysis::~ManagedAnalysis() {}
435
436AnalysisDeclContext::~AnalysisDeclContext() {
437  delete forcedBlkExprs;
438  delete ReferencedBlockVars;
439  // Release the managed analyses.
440  if (ManagedAnalyses) {
441    ManagedAnalysisMap *M = (ManagedAnalysisMap*) ManagedAnalyses;
442    for (ManagedAnalysisMap::iterator I = M->begin(), E = M->end(); I!=E; ++I)
443      delete I->second;
444    delete M;
445  }
446}
447
448AnalysisDeclContextManager::~AnalysisDeclContextManager() {
449  for (ContextMap::iterator I = Contexts.begin(), E = Contexts.end(); I!=E; ++I)
450    delete I->second;
451}
452
453LocationContext::~LocationContext() {}
454
455LocationContextManager::~LocationContextManager() {
456  clear();
457}
458
459void LocationContextManager::clear() {
460  for (llvm::FoldingSet<LocationContext>::iterator I = Contexts.begin(),
461       E = Contexts.end(); I != E; ) {
462    LocationContext *LC = &*I;
463    ++I;
464    delete LC;
465  }
466
467  Contexts.clear();
468}
469
470