clang/Analysis/AnalysisContext.h

//=== AnalysisContext.h - Analysis context for Path Sens analysis --*- C++ -*-//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines AnalysisContext, a class that manages the analysis context
// data for path sensitive analysis.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_ANALYSIS_ANALYSISCONTEXT_H
#define LLVM_CLANG_ANALYSIS_ANALYSISCONTEXT_H

#include "clang/AST/Decl.h"
#include "clang/AST/Expr.h"
#include "clang/Analysis/CFG.h"
#include "llvm/ADT/OwningPtr.h"
#include "llvm/ADT/IntrusiveRefCntPtr.h"
#include "llvm/ADT/FoldingSet.h"
#include "llvm/ADT/PointerUnion.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/Support/Allocator.h"

namespace clang {

class Decl;
class Stmt;
class CFGReverseBlockReachabilityAnalysis;
class CFGStmtMap;
class LiveVariables;
class ManagedAnalysis;
class ParentMap;
class PseudoConstantAnalysis;
class ImplicitParamDecl;
class LocationContextManager;
class StackFrameContext;
class AnalysisContextManager;
class LocationContext;

namespace idx { class TranslationUnit; }

/// The base class of a hierarchy of objects representing analyses tied
/// to AnalysisContext.
class ManagedAnalysis {
protected:
  ManagedAnalysis() {}
public:
  virtual ~ManagedAnalysis();

  // Subclasses need to implement:
  //
  //  static const void *getTag();
  //
  // Which returns a fixed pointer address to distinguish classes of
  // analysis objects.  They also need to implement:
  //
  //  static [Derived*] create(AnalysisContext &Ctx);
  //
  // which creates the analysis object given an AnalysisContext.
};


/// AnalysisContext contains the context data for the function or method under
/// analysis.
class AnalysisContext {
  /// Backpoint to the AnalysisManager object that created this AnalysisContext.
  /// This may be null.
  AnalysisContextManager *Manager;

  const Decl *D;

  // TranslationUnit is NULL if we don't have multiple translation units.
  idx::TranslationUnit *TU;

  llvm::OwningPtr<CFG> cfg, completeCFG;
  llvm::OwningPtr<CFGStmtMap> cfgStmtMap;

  CFG::BuildOptions cfgBuildOptions;
  CFG::BuildOptions::ForcedBlkExprs *forcedBlkExprs;

  bool builtCFG, builtCompleteCFG;

  llvm::OwningPtr<LiveVariables> liveness;
  llvm::OwningPtr<LiveVariables> relaxedLiveness;
  llvm::OwningPtr<ParentMap> PM;
  llvm::OwningPtr<PseudoConstantAnalysis> PCA;
  llvm::OwningPtr<CFGReverseBlockReachabilityAnalysis> CFA;

  llvm::BumpPtrAllocator A;

  // FIXME: remove.
  llvm::DenseMap<const BlockDecl*,void*> *ReferencedBlockVars;

  void *ManagedAnalyses;

public:
  AnalysisContext(AnalysisContextManager *Mgr,
                  const Decl *D,
                  idx::TranslationUnit *TU);

  AnalysisContext(AnalysisContextManager *Mgr,
                  const Decl *D,
                  idx::TranslationUnit *TU,
                  const CFG::BuildOptions &BuildOptions);

  ~AnalysisContext();

  ASTContext &getASTContext() { return D->getASTContext(); }
  const Decl *getDecl() const { return D; }

  idx::TranslationUnit *getTranslationUnit() const { return TU; }

  /// Return the build options used to construct the CFG.
  CFG::BuildOptions &getCFGBuildOptions() {
    return cfgBuildOptions;
  }

  const CFG::BuildOptions &getCFGBuildOptions() const {
    return cfgBuildOptions;
  }

  /// getAddEHEdges - Return true iff we are adding exceptional edges from
  /// callExprs.  If this is false, then try/catch statements and blocks
  /// reachable from them can appear to be dead in the CFG, analysis passes must
  /// cope with that.
  bool getAddEHEdges() const { return cfgBuildOptions.AddEHEdges; }
  bool getUseUnoptimizedCFG() const {
      return !cfgBuildOptions.PruneTriviallyFalseEdges;
  }
  bool getAddImplicitDtors() const { return cfgBuildOptions.AddImplicitDtors; }
  bool getAddInitializers() const { return cfgBuildOptions.AddInitializers; }

  void registerForcedBlockExpression(const Stmt *stmt);
  const CFGBlock *getBlockForRegisteredExpression(const Stmt *stmt);

  Stmt *getBody() const;
  CFG *getCFG();

  CFGStmtMap *getCFGStmtMap();

  CFGReverseBlockReachabilityAnalysis *getCFGReachablityAnalysis();

  /// Return a version of the CFG without any edges pruned.
  CFG *getUnoptimizedCFG();

  void dumpCFG();

  /// \brief Returns true if we have built a CFG for this analysis context.
  /// Note that this doesn't correspond to whether or not a valid CFG exists, it
  /// corresponds to whether we *attempted* to build one.
  bool isCFGBuilt() const { return builtCFG; }

  ParentMap &getParentMap();
  PseudoConstantAnalysis *getPseudoConstantAnalysis();

  typedef const VarDecl * const * referenced_decls_iterator;

  std::pair<referenced_decls_iterator, referenced_decls_iterator>
    getReferencedBlockVars(const BlockDecl *BD);

  /// Return the ImplicitParamDecl* associated with 'self' if this
  /// AnalysisContext wraps an ObjCMethodDecl.  Returns NULL otherwise.
  const ImplicitParamDecl *getSelfDecl() const;

  const StackFrameContext *getStackFrame(LocationContext const *Parent,
                                         const Stmt *S,
                                         const CFGBlock *Blk,
                                         unsigned Idx);

  /// Return the specified analysis object, lazily running the analysis if
  /// necessary.  Return NULL if the analysis could not run.
  template <typename T>
  T *getAnalysis() {
    const void *tag = T::getTag();
    ManagedAnalysis *&data = getAnalysisImpl(tag);
    if (!data) {
      data = T::create(*this);
    }
    return static_cast<T*>(data);
  }
private:
  ManagedAnalysis *&getAnalysisImpl(const void* tag);

  LocationContextManager &getLocationContextManager();
};

class LocationContext : public llvm::FoldingSetNode {
public:
  enum ContextKind { StackFrame, Scope, Block };

private:
  ContextKind Kind;

  // AnalysisContext can't be const since some methods may modify its member.
  AnalysisContext *Ctx;

  const LocationContext *Parent;

protected:
  LocationContext(ContextKind k, AnalysisContext *ctx,
                  const LocationContext *parent)
    : Kind(k), Ctx(ctx), Parent(parent) {}

public:
  virtual ~LocationContext();

  ContextKind getKind() const { return Kind; }

  AnalysisContext *getAnalysisContext() const { return Ctx; }

  idx::TranslationUnit *getTranslationUnit() const {
    return Ctx->getTranslationUnit();
  }

  const LocationContext *getParent() const { return Parent; }

  bool isParentOf(const LocationContext *LC) const;

  const Decl *getDecl() const { return getAnalysisContext()->getDecl(); }

  CFG *getCFG() const { return getAnalysisContext()->getCFG(); }

  template <typename T>
  T *getAnalysis() const {
    return getAnalysisContext()->getAnalysis<T>();
  }

  ParentMap &getParentMap() const {
    return getAnalysisContext()->getParentMap();
  }

  const ImplicitParamDecl *getSelfDecl() const {
    return Ctx->getSelfDecl();
  }

  const StackFrameContext *getCurrentStackFrame() const;
  const StackFrameContext *
    getStackFrameForDeclContext(const DeclContext *DC) const;

  virtual void Profile(llvm::FoldingSetNodeID &ID) = 0;

  static bool classof(const LocationContext*) { return true; }

public:
  static void ProfileCommon(llvm::FoldingSetNodeID &ID,
                            ContextKind ck,
                            AnalysisContext *ctx,
                            const LocationContext *parent,
                            const void *data);
};

class StackFrameContext : public LocationContext {
  // The callsite where this stack frame is established.
  const Stmt *CallSite;

  // The parent block of the callsite.
  const CFGBlock *Block;

  // The index of the callsite in the CFGBlock.
  unsigned Index;

  friend class LocationContextManager;
  StackFrameContext(AnalysisContext *ctx, const LocationContext *parent,
                    const Stmt *s, const CFGBlock *blk,
                    unsigned idx)
    : LocationContext(StackFrame, ctx, parent), CallSite(s),
      Block(blk), Index(idx) {}

public:
  ~StackFrameContext() {}

  const Stmt *getCallSite() const { return CallSite; }

  const CFGBlock *getCallSiteBlock() const { return Block; }

  unsigned getIndex() const { return Index; }

  void Profile(llvm::FoldingSetNodeID &ID);

  static void Profile(llvm::FoldingSetNodeID &ID, AnalysisContext *ctx,
                      const LocationContext *parent, const Stmt *s,
                      const CFGBlock *blk, unsigned idx) {
    ProfileCommon(ID, StackFrame, ctx, parent, s);
    ID.AddPointer(blk);
    ID.AddInteger(idx);
  }

  static bool classof(const LocationContext *Ctx) {
    return Ctx->getKind() == StackFrame;
  }
};

class ScopeContext : public LocationContext {
  const Stmt *Enter;

  friend class LocationContextManager;
  ScopeContext(AnalysisContext *ctx, const LocationContext *parent,
               const Stmt *s)
    : LocationContext(Scope, ctx, parent), Enter(s) {}

public:
  ~ScopeContext() {}

  void Profile(llvm::FoldingSetNodeID &ID);

  static void Profile(llvm::FoldingSetNodeID &ID, AnalysisContext *ctx,
                      const LocationContext *parent, const Stmt *s) {
    ProfileCommon(ID, Scope, ctx, parent, s);
  }

  static bool classof(const LocationContext *Ctx) {
    return Ctx->getKind() == Scope;
  }
};

class BlockInvocationContext : public LocationContext {
  // FIXME: Add back context-sensivity (we don't want libAnalysis to know
  //  about MemRegion).
  const BlockDecl *BD;

  friend class LocationContextManager;

  BlockInvocationContext(AnalysisContext *ctx, const LocationContext *parent,
                         const BlockDecl *bd)
    : LocationContext(Block, ctx, parent), BD(bd) {}

public:
  ~BlockInvocationContext() {}

  const BlockDecl *getBlockDecl() const { return BD; }

  void Profile(llvm::FoldingSetNodeID &ID);

  static void Profile(llvm::FoldingSetNodeID &ID, AnalysisContext *ctx,
                      const LocationContext *parent, const BlockDecl *bd) {
    ProfileCommon(ID, Block, ctx, parent, bd);
  }

  static bool classof(const LocationContext *Ctx) {
    return Ctx->getKind() == Block;
  }
};

class LocationContextManager {
  llvm::FoldingSet<LocationContext> Contexts;
public:
  ~LocationContextManager();

  const StackFrameContext *getStackFrame(AnalysisContext *ctx,
                                         const LocationContext *parent,
                                         const Stmt *s,
                                         const CFGBlock *blk, unsigned idx);

  const ScopeContext *getScope(AnalysisContext *ctx,
                               const LocationContext *parent,
                               const Stmt *s);

  /// Discard all previously created LocationContext objects.
  void clear();
private:
  template <typename LOC, typename DATA>
  const LOC *getLocationContext(AnalysisContext *ctx,
                                const LocationContext *parent,
                                const DATA *d);
};

class AnalysisContextManager {
  typedef llvm::DenseMap<const Decl*, AnalysisContext*> ContextMap;

  ContextMap Contexts;
  LocationContextManager LocContexts;
  CFG::BuildOptions cfgBuildOptions;

public:
  AnalysisContextManager(bool useUnoptimizedCFG = false,
                         bool addImplicitDtors = false,
                         bool addInitializers = false);

  ~AnalysisContextManager();

  AnalysisContext *getContext(const Decl *D, idx::TranslationUnit *TU = 0);

  bool getUseUnoptimizedCFG() const {
    return !cfgBuildOptions.PruneTriviallyFalseEdges;
  }

  CFG::BuildOptions &getCFGBuildOptions() {
    return cfgBuildOptions;
  }

  const StackFrameContext *getStackFrame(AnalysisContext *Ctx,
                                         LocationContext const *Parent,
                                         const Stmt *S,
                                         const CFGBlock *Blk,
                                         unsigned Idx) {
    return LocContexts.getStackFrame(Ctx, Parent, S, Blk, Idx);
  }

  // Get the top level stack frame.
  const StackFrameContext *getStackFrame(Decl const *D,
                                         idx::TranslationUnit *TU) {
    return LocContexts.getStackFrame(getContext(D, TU), 0, 0, 0, 0);
  }

  // Get a stack frame with parent.
  StackFrameContext const *getStackFrame(const Decl *D,
                                         LocationContext const *Parent,
                                         const Stmt *S,
                                         const CFGBlock *Blk,
                                         unsigned Idx) {
    return LocContexts.getStackFrame(getContext(D), Parent, S, Blk, Idx);
  }


  /// Discard all previously created AnalysisContexts.
  void clear();

private:
  friend class AnalysisContext;

  LocationContextManager &getLocationContextManager() {
    return LocContexts;
  }
};

} // end clang namespace
#endif