AnalysisDeclContext.cpp revision 22c0cbee5bb2150841e0046354fd37ba22de747a 
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
33using namespace clang;
34
35typedef llvm::DenseMap<const void *, ManagedAnalysis *> ManagedAnalysisMap;
36
37AnalysisDeclContext::AnalysisDeclContext(AnalysisDeclContextManager *Mgr,
38                                         const Decl *d,
39                                         const CFG::BuildOptions &buildOptions)
40  : Manager(Mgr),
41    D(d),
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: Manager(Mgr),
55  D(d),
56  forcedBlkExprs(0),
57  builtCFG(false),
58  builtCompleteCFG(false),
59  ReferencedBlockVars(0),
60  ManagedAnalyses(0)
61{
62  cfgBuildOptions.forcedBlkExprs = &forcedBlkExprs;
63}
64
65AnalysisDeclContextManager::AnalysisDeclContextManager(bool useUnoptimizedCFG,
66                                                       bool addImplicitDtors,
67                                                       bool addInitializers,
68                                                       bool addTemporaryDtors,
69                                                       bool synthesizeBodies)
70  : SynthesizeBodies(synthesizeBodies)
71{
72  cfgBuildOptions.PruneTriviallyFalseEdges = !useUnoptimizedCFG;
73  cfgBuildOptions.AddImplicitDtors = addImplicitDtors;
74  cfgBuildOptions.AddInitializers = addInitializers;
75  cfgBuildOptions.AddTemporaryDtors = addTemporaryDtors;
76}
77
78void AnalysisDeclContextManager::clear() {
79  for (ContextMap::iterator I = Contexts.begin(), E = Contexts.end(); I!=E; ++I)
80    delete I->second;
81  Contexts.clear();
82}
83
84static BodyFarm &getBodyFarm(ASTContext &C) {
85  static BodyFarm *BF = new BodyFarm(C);
86  return *BF;
87}
88
89Stmt *AnalysisDeclContext::getBody(bool &IsAutosynthesized) const {
90  IsAutosynthesized = false;
91  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
92    Stmt *Body = FD->getBody();
93    if (!Body && Manager && Manager->synthesizeBodies()) {
94      IsAutosynthesized = true;
95      return getBodyFarm(getASTContext()).getBody(FD);
96    }
97    return Body;
98  }
99  else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D))
100    return MD->getBody();
101  else if (const BlockDecl *BD = dyn_cast<BlockDecl>(D))
102    return BD->getBody();
103  else if (const FunctionTemplateDecl *FunTmpl
104           = dyn_cast_or_null<FunctionTemplateDecl>(D))
105    return FunTmpl->getTemplatedDecl()->getBody();
106
107  llvm_unreachable("unknown code decl");
108}
109
110Stmt *AnalysisDeclContext::getBody() const {
111  bool Tmp;
112  return getBody(Tmp);
113}
114
115bool AnalysisDeclContext::isBodyAutosynthesized() const {
116  bool Tmp;
117  getBody(Tmp);
118  return Tmp;
119}
120
121const ImplicitParamDecl *AnalysisDeclContext::getSelfDecl() const {
122  if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D))
123    return MD->getSelfDecl();
124  if (const BlockDecl *BD = dyn_cast<BlockDecl>(D)) {
125    // See if 'self' was captured by the block.
126    for (BlockDecl::capture_const_iterator it = BD->capture_begin(),
127         et = BD->capture_end(); it != et; ++it) {
128      const VarDecl *VD = it->getVariable();
129      if (VD->getName() == "self")
130        return dyn_cast<ImplicitParamDecl>(VD);
131    }
132  }
133
134  return NULL;
135}
136
137void AnalysisDeclContext::registerForcedBlockExpression(const Stmt *stmt) {
138  if (!forcedBlkExprs)
139    forcedBlkExprs = new CFG::BuildOptions::ForcedBlkExprs();
140  // Default construct an entry for 'stmt'.
141  if (const Expr *e = dyn_cast<Expr>(stmt))
142    stmt = e->IgnoreParens();
143  (void) (*forcedBlkExprs)[stmt];
144}
145
146const CFGBlock *
147AnalysisDeclContext::getBlockForRegisteredExpression(const Stmt *stmt) {
148  assert(forcedBlkExprs);
149  if (const Expr *e = dyn_cast<Expr>(stmt))
150    stmt = e->IgnoreParens();
151  CFG::BuildOptions::ForcedBlkExprs::const_iterator itr =
152    forcedBlkExprs->find(stmt);
153  assert(itr != forcedBlkExprs->end());
154  return itr->second;
155}
156
157CFG *AnalysisDeclContext::getCFG() {
158  if (!cfgBuildOptions.PruneTriviallyFalseEdges)
159    return getUnoptimizedCFG();
160
161  if (!builtCFG) {
162    cfg.reset(CFG::buildCFG(D, getBody(),
163                            &D->getASTContext(), cfgBuildOptions));
164    // Even when the cfg is not successfully built, we don't
165    // want to try building it again.
166    builtCFG = true;
167  }
168  return cfg.get();
169}
170
171CFG *AnalysisDeclContext::getUnoptimizedCFG() {
172  if (!builtCompleteCFG) {
173    SaveAndRestore<bool> NotPrune(cfgBuildOptions.PruneTriviallyFalseEdges,
174                                  false);
175    completeCFG.reset(CFG::buildCFG(D, getBody(), &D->getASTContext(),
176                                    cfgBuildOptions));
177    // Even when the cfg is not successfully built, we don't
178    // want to try building it again.
179    builtCompleteCFG = true;
180  }
181  return completeCFG.get();
182}
183
184CFGStmtMap *AnalysisDeclContext::getCFGStmtMap() {
185  if (cfgStmtMap)
186    return cfgStmtMap.get();
187
188  if (CFG *c = getCFG()) {
189    cfgStmtMap.reset(CFGStmtMap::Build(c, &getParentMap()));
190    return cfgStmtMap.get();
191  }
192
193  return 0;
194}
195
196CFGReverseBlockReachabilityAnalysis *AnalysisDeclContext::getCFGReachablityAnalysis() {
197  if (CFA)
198    return CFA.get();
199
200  if (CFG *c = getCFG()) {
201    CFA.reset(new CFGReverseBlockReachabilityAnalysis(*c));
202    return CFA.get();
203  }
204
205  return 0;
206}
207
208void AnalysisDeclContext::dumpCFG(bool ShowColors) {
209    getCFG()->dump(getASTContext().getLangOpts(), ShowColors);
210}
211
212ParentMap &AnalysisDeclContext::getParentMap() {
213  if (!PM) {
214    PM.reset(new ParentMap(getBody()));
215    if (const CXXConstructorDecl *C = dyn_cast<CXXConstructorDecl>(getDecl())) {
216      for (CXXConstructorDecl::init_const_iterator I = C->init_begin(),
217                                                   E = C->init_end();
218           I != E; ++I) {
219        PM->addStmt((*I)->getInit());
220      }
221    }
222  }
223  return *PM;
224}
225
226PseudoConstantAnalysis *AnalysisDeclContext::getPseudoConstantAnalysis() {
227  if (!PCA)
228    PCA.reset(new PseudoConstantAnalysis(getBody()));
229  return PCA.get();
230}
231
232AnalysisDeclContext *AnalysisDeclContextManager::getContext(const Decl *D) {
233  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
234    // Calling 'hasBody' replaces 'FD' in place with the FunctionDecl
235    // that has the body.
236    FD->hasBody(FD);
237    D = FD;
238  }
239
240  AnalysisDeclContext *&AC = Contexts[D];
241  if (!AC)
242    AC = new AnalysisDeclContext(this, D, cfgBuildOptions);
243  return AC;
244}
245
246const StackFrameContext *
247AnalysisDeclContext::getStackFrame(LocationContext const *Parent, const Stmt *S,
248                               const CFGBlock *Blk, unsigned Idx) {
249  return getLocationContextManager().getStackFrame(this, Parent, S, Blk, Idx);
250}
251
252const BlockInvocationContext *
253AnalysisDeclContext::getBlockInvocationContext(const LocationContext *parent,
254                                               const clang::BlockDecl *BD,
255                                               const void *ContextData) {
256  return getLocationContextManager().getBlockInvocationContext(this, parent,
257                                                               BD, ContextData);
258}
259
260LocationContextManager & AnalysisDeclContext::getLocationContextManager() {
261  assert(Manager &&
262         "Cannot create LocationContexts without an AnalysisDeclContextManager!");
263  return Manager->getLocationContextManager();
264}
265
266//===----------------------------------------------------------------------===//
267// FoldingSet profiling.
268//===----------------------------------------------------------------------===//
269
270void LocationContext::ProfileCommon(llvm::FoldingSetNodeID &ID,
271                                    ContextKind ck,
272                                    AnalysisDeclContext *ctx,
273                                    const LocationContext *parent,
274                                    const void *data) {
275  ID.AddInteger(ck);
276  ID.AddPointer(ctx);
277  ID.AddPointer(parent);
278  ID.AddPointer(data);
279}
280
281void StackFrameContext::Profile(llvm::FoldingSetNodeID &ID) {
282  Profile(ID, getAnalysisDeclContext(), getParent(), CallSite, Block, Index);
283}
284
285void ScopeContext::Profile(llvm::FoldingSetNodeID &ID) {
286  Profile(ID, getAnalysisDeclContext(), getParent(), Enter);
287}
288
289void BlockInvocationContext::Profile(llvm::FoldingSetNodeID &ID) {
290  Profile(ID, getAnalysisDeclContext(), getParent(), BD, ContextData);
291}
292
293//===----------------------------------------------------------------------===//
294// LocationContext creation.
295//===----------------------------------------------------------------------===//
296
297template <typename LOC, typename DATA>
298const LOC*
299LocationContextManager::getLocationContext(AnalysisDeclContext *ctx,
300                                           const LocationContext *parent,
301                                           const DATA *d) {
302  llvm::FoldingSetNodeID ID;
303  LOC::Profile(ID, ctx, parent, d);
304  void *InsertPos;
305
306  LOC *L = cast_or_null<LOC>(Contexts.FindNodeOrInsertPos(ID, InsertPos));
307
308  if (!L) {
309    L = new LOC(ctx, parent, d);
310    Contexts.InsertNode(L, InsertPos);
311  }
312  return L;
313}
314
315const StackFrameContext*
316LocationContextManager::getStackFrame(AnalysisDeclContext *ctx,
317                                      const LocationContext *parent,
318                                      const Stmt *s,
319                                      const CFGBlock *blk, unsigned idx) {
320  llvm::FoldingSetNodeID ID;
321  StackFrameContext::Profile(ID, ctx, parent, s, blk, idx);
322  void *InsertPos;
323  StackFrameContext *L =
324   cast_or_null<StackFrameContext>(Contexts.FindNodeOrInsertPos(ID, InsertPos));
325  if (!L) {
326    L = new StackFrameContext(ctx, parent, s, blk, idx);
327    Contexts.InsertNode(L, InsertPos);
328  }
329  return L;
330}
331
332const ScopeContext *
333LocationContextManager::getScope(AnalysisDeclContext *ctx,
334                                 const LocationContext *parent,
335                                 const Stmt *s) {
336  return getLocationContext<ScopeContext, Stmt>(ctx, parent, s);
337}
338
339const BlockInvocationContext *
340LocationContextManager::getBlockInvocationContext(AnalysisDeclContext *ctx,
341                                                  const LocationContext *parent,
342                                                  const BlockDecl *BD,
343                                                  const void *ContextData) {
344  llvm::FoldingSetNodeID ID;
345  BlockInvocationContext::Profile(ID, ctx, parent, BD, ContextData);
346  void *InsertPos;
347  BlockInvocationContext *L =
348    cast_or_null<BlockInvocationContext>(Contexts.FindNodeOrInsertPos(ID,
349                                                                    InsertPos));
350  if (!L) {
351    L = new BlockInvocationContext(ctx, parent, BD, ContextData);
352    Contexts.InsertNode(L, InsertPos);
353  }
354  return L;
355}
356
357//===----------------------------------------------------------------------===//
358// LocationContext methods.
359//===----------------------------------------------------------------------===//
360
361const StackFrameContext *LocationContext::getCurrentStackFrame() const {
362  const LocationContext *LC = this;
363  while (LC) {
364    if (const StackFrameContext *SFC = dyn_cast<StackFrameContext>(LC))
365      return SFC;
366    LC = LC->getParent();
367  }
368  return NULL;
369}
370
371bool LocationContext::inTopFrame() const {
372  return getCurrentStackFrame()->inTopFrame();
373}
374
375bool LocationContext::isParentOf(const LocationContext *LC) const {
376  do {
377    const LocationContext *Parent = LC->getParent();
378    if (Parent == this)
379      return true;
380    else
381      LC = Parent;
382  } while (LC);
383
384  return false;
385}
386
387//===----------------------------------------------------------------------===//
388// Lazily generated map to query the external variables referenced by a Block.
389//===----------------------------------------------------------------------===//
390
391namespace {
392class FindBlockDeclRefExprsVals : public StmtVisitor<FindBlockDeclRefExprsVals>{
393  BumpVector<const VarDecl*> &BEVals;
394  BumpVectorContext &BC;
395  llvm::SmallPtrSet<const VarDecl*, 4> Visited;
396  llvm::SmallPtrSet<const DeclContext*, 4> IgnoredContexts;
397public:
398  FindBlockDeclRefExprsVals(BumpVector<const VarDecl*> &bevals,
399                            BumpVectorContext &bc)
400  : BEVals(bevals), BC(bc) {}
401
402  bool IsTrackedDecl(const VarDecl *VD) {
403    const DeclContext *DC = VD->getDeclContext();
404    return IgnoredContexts.count(DC) == 0;
405  }
406
407  void VisitStmt(Stmt *S) {
408    for (Stmt::child_range I = S->children(); I; ++I)
409      if (Stmt *child = *I)
410        Visit(child);
411  }
412
413  void VisitDeclRefExpr(DeclRefExpr *DR) {
414    // Non-local variables are also directly modified.
415    if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) {
416      if (!VD->hasLocalStorage()) {
417        if (Visited.insert(VD))
418          BEVals.push_back(VD, BC);
419      }
420    }
421  }
422
423  void VisitBlockExpr(BlockExpr *BR) {
424    // Blocks containing blocks can transitively capture more variables.
425    IgnoredContexts.insert(BR->getBlockDecl());
426    Visit(BR->getBlockDecl()->getBody());
427  }
428
429  void VisitPseudoObjectExpr(PseudoObjectExpr *PE) {
430    for (PseudoObjectExpr::semantics_iterator it = PE->semantics_begin(),
431         et = PE->semantics_end(); it != et; ++it) {
432      Expr *Semantic = *it;
433      if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic))
434        Semantic = OVE->getSourceExpr();
435      Visit(Semantic);
436    }
437  }
438};
439} // end anonymous namespace
440
441typedef BumpVector<const VarDecl*> DeclVec;
442
443static DeclVec* LazyInitializeReferencedDecls(const BlockDecl *BD,
444                                              void *&Vec,
445                                              llvm::BumpPtrAllocator &A) {
446  if (Vec)
447    return (DeclVec*) Vec;
448
449  BumpVectorContext BC(A);
450  DeclVec *BV = (DeclVec*) A.Allocate<DeclVec>();
451  new (BV) DeclVec(BC, 10);
452
453  // Go through the capture list.
454  for (BlockDecl::capture_const_iterator CI = BD->capture_begin(),
455       CE = BD->capture_end(); CI != CE; ++CI) {
456    BV->push_back(CI->getVariable(), BC);
457  }
458
459  // Find the referenced global/static variables.
460  FindBlockDeclRefExprsVals F(*BV, BC);
461  F.Visit(BD->getBody());
462
463  Vec = BV;
464  return BV;
465}
466
467std::pair<AnalysisDeclContext::referenced_decls_iterator,
468          AnalysisDeclContext::referenced_decls_iterator>
469AnalysisDeclContext::getReferencedBlockVars(const BlockDecl *BD) {
470  if (!ReferencedBlockVars)
471    ReferencedBlockVars = new llvm::DenseMap<const BlockDecl*,void*>();
472
473  DeclVec *V = LazyInitializeReferencedDecls(BD, (*ReferencedBlockVars)[BD], A);
474  return std::make_pair(V->begin(), V->end());
475}
476
477ManagedAnalysis *&AnalysisDeclContext::getAnalysisImpl(const void *tag) {
478  if (!ManagedAnalyses)
479    ManagedAnalyses = new ManagedAnalysisMap();
480  ManagedAnalysisMap *M = (ManagedAnalysisMap*) ManagedAnalyses;
481  return (*M)[tag];
482}
483
484//===----------------------------------------------------------------------===//
485// Cleanup.
486//===----------------------------------------------------------------------===//
487
488ManagedAnalysis::~ManagedAnalysis() {}
489
490AnalysisDeclContext::~AnalysisDeclContext() {
491  delete forcedBlkExprs;
492  delete ReferencedBlockVars;
493  // Release the managed analyses.
494  if (ManagedAnalyses) {
495    ManagedAnalysisMap *M = (ManagedAnalysisMap*) ManagedAnalyses;
496    for (ManagedAnalysisMap::iterator I = M->begin(), E = M->end(); I!=E; ++I)
497      delete I->second;
498    delete M;
499  }
500}
501
502AnalysisDeclContextManager::~AnalysisDeclContextManager() {
503  for (ContextMap::iterator I = Contexts.begin(), E = Contexts.end(); I!=E; ++I)
504    delete I->second;
505}
506
507LocationContext::~LocationContext() {}
508
509LocationContextManager::~LocationContextManager() {
510  clear();
511}
512
513void LocationContextManager::clear() {
514  for (llvm::FoldingSet<LocationContext>::iterator I = Contexts.begin(),
515       E = Contexts.end(); I != E; ) {
516    LocationContext *LC = &*I;
517    ++I;
518    delete LC;
519  }
520
521  Contexts.clear();
522}
523
524