path: root/Analysis/GRExprEngine.cpp

//=-- GRExprEngine.cpp - Path-Sensitive Expression-Level Dataflow ---*- 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 a meta-engine for path-sensitive dataflow analysis that
//  is built on GREngine, but provides the boilerplate to execute transfer
//  functions and build the ExplodedGraph at the expression level.
//
//===----------------------------------------------------------------------===//

#include "clang/Analysis/PathSensitive/GRExprEngine.h"
#include "clang/Analysis/PathSensitive/GRTransferFuncs.h"

#include "llvm/Support/Streams.h"

using namespace clang;
using llvm::dyn_cast;
using llvm::cast;
using llvm::APSInt;

GRExprEngine::StateTy
GRExprEngine::SetValue(StateTy St, Expr* S, const RValue& V) {

  if (!StateCleaned) {
    St = RemoveDeadBindings(CurrentStmt, St);
    StateCleaned = true;
  }

  bool isBlkExpr = false;
    
  if (S == CurrentStmt) {
    isBlkExpr = getCFG().isBlkExpr(S);
    
    if (!isBlkExpr)
      return St;
  }

  return StateMgr.SetValue(St, S, isBlkExpr, V);
}

const GRExprEngine::StateTy::BufferTy&
GRExprEngine::SetValue(StateTy St, Expr* S, const RValue::BufferTy& RB,
                      StateTy::BufferTy& RetBuf) {
  
  assert (RetBuf.empty());
  
  for (RValue::BufferTy::const_iterator I=RB.begin(), E=RB.end(); I!=E; ++I)
    RetBuf.push_back(SetValue(St, S, *I));
                     
  return RetBuf;
}

GRExprEngine::StateTy
GRExprEngine::SetValue(StateTy St, const LValue& LV, const RValue& V) {
  
  if (LV.isUnknown())
    return St;
  
  if (!StateCleaned) {
    St = RemoveDeadBindings(CurrentStmt, St);
    StateCleaned = true;
  }
  
  return StateMgr.SetValue(St, LV, V);
}

void GRExprEngine::ProcessBranch(Expr* Condition, Stmt* Term,
                                BranchNodeBuilder& builder) {

  // Remove old bindings for subexpressions.
  StateTy PrevState = StateMgr.RemoveSubExprBindings(builder.getState());
  
  RValue V = GetValue(PrevState, Condition);
  
  switch (V.getBaseKind()) {
    default:
      break;

    case RValue::UnknownKind:
      builder.generateNode(PrevState, true);
      builder.generateNode(PrevState, false);
      return;
      
    case RValue::UninitializedKind: {      
      NodeTy* N = builder.generateNode(PrevState, true);

      if (N) {
        N->markAsSink();
        UninitBranches.insert(N);
      }
      
      builder.markInfeasible(false);
      return;
    }      
  }

  // Get the current block counter.
  GRBlockCounter BC = builder.getBlockCounter();
    
  unsigned BlockID = builder.getTargetBlock(true)->getBlockID();