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/**CFile****************************************************************
FileName [saigBmc.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [Sequential AIG package.]
Synopsis [Simple BMC package.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - June 20, 2005.]
Revision [$Id: saigBmc.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]
***********************************************************************/
#include "saig.h"
#include "cnf.h"
#include "satStore.h"
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
#define AIG_VISITED ((Aig_Obj_t *)(PORT_PTRUINT_T)1)
typedef struct Saig_Bmc_t_ Saig_Bmc_t;
struct Saig_Bmc_t_
{
// parameters
int nFramesMax; // the max number of timeframes to consider
int nConfMaxOne; // the max number of conflicts at a target
int nConfMaxAll; // the max number of conflicts for all targets
int nNodesMax; // the max number of nodes to add
int fVerbose; // enables verbose output
// AIG managers
Aig_Man_t * pAig; // the user's AIG manager
Aig_Man_t * pFrm; // Frames manager
Vec_Ptr_t * vVisited; // nodes visited in Frames
// node mapping
int nObjs; // the largest number of an AIG object
Vec_Ptr_t * vAig2Frm; // mapping of AIG nodees into Frames nodes
// SAT solver
sat_solver * pSat; // SAT solver
Vec_Int_t * vObj2Var; // mapping of frames objects in CNF variables
int nSatVars; // the number of used SAT variables
Vec_Ptr_t * vTargets; // targets to be solved in this interval
int iFramelast; // last frame
int iOutputLast; // last output
};
static inline int Saig_BmcSatNum( Saig_Bmc_t * p, Aig_Obj_t * pObj ) { return Vec_IntGetEntry( p->vObj2Var, pObj->Id ); }
static inline void Saig_BmcSetSatNum( Saig_Bmc_t * p, Aig_Obj_t * pObj, int Num ) { Vec_IntSetEntry(p->vObj2Var, pObj->Id, Num); }
static inline Aig_Obj_t * Saig_BmcObjFrame( Saig_Bmc_t * p, Aig_Obj_t * pObj, int i ) { return Vec_PtrGetEntry( p->vAig2Frm, p->nObjs*i+pObj->Id ); }
static inline void Saig_BmcObjSetFrame( Saig_Bmc_t * p, Aig_Obj_t * pObj, int i, Aig_Obj_t * pNode ) { Vec_PtrSetEntry( p->vAig2Frm, p->nObjs*i+pObj->Id, pNode ); }
static inline Aig_Obj_t * Saig_BmcObjChild0( Saig_Bmc_t * p, Aig_Obj_t * pObj, int i ) { assert( !Aig_IsComplement(pObj) ); return Aig_NotCond(Saig_BmcObjFrame(p, Aig_ObjFanin0(pObj), i), Aig_ObjFaninC0(pObj)); }
static inline Aig_Obj_t * Saig_BmcObjChild1( Saig_Bmc_t * p, Aig_Obj_t * pObj, int i ) { assert( !Aig_IsComplement(pObj) ); return Aig_NotCond(Saig_BmcObjFrame(p, Aig_ObjFanin1(pObj), i), Aig_ObjFaninC1(pObj)); }
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Create manager.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Saig_Bmc_t * Saig_BmcManStart( Aig_Man_t * pAig, int nConfMaxOne, int nConfMaxAll, int nNodesMax, int fVerbose )
{
Saig_Bmc_t * p;
Aig_Obj_t * pObj;
int i, Lit;
assert( Aig_ManRegNum(pAig) > 0 );
p = (Saig_Bmc_t *)malloc( sizeof(Saig_Bmc_t) );
memset( p, 0, sizeof(Saig_Bmc_t) );
// set parameters
p->nFramesMax = 1000000;
p->nConfMaxOne = nConfMaxOne;
p->nConfMaxAll = nConfMaxAll;
p->nNodesMax = nNodesMax;
p->fVerbose = fVerbose;
p->pAig = pAig;
p->nObjs = Aig_ManObjNumMax(pAig);
// create node and variable mappings
p->vAig2Frm = Vec_PtrAlloc( 0 );
Vec_PtrFill( p->vAig2Frm, 5 * p->nObjs, NULL );
p->vObj2Var = Vec_IntAlloc( 0 );
Vec_IntFill( p->vObj2Var, 5 * p->nObjs, 0 );
// start the AIG manager and map primary inputs
p->pFrm = Aig_ManStart( 5 * p->nObjs );
Saig_ManForEachLo( pAig, pObj, i )
Saig_BmcObjSetFrame( p, pObj, 0, Aig_ManConst0(p->pFrm) );
// create SAT solver
p->pSat = sat_solver_new();
sat_solver_setnvars( p->pSat, 2000 );
p->nSatVars = 1;
Lit = toLit( p->nSatVars );
sat_solver_addclause( p->pSat, &Lit, &Lit + 1 );
Saig_BmcSetSatNum( p, Aig_ManConst1(p->pFrm), p->nSatVars++ );
// other data structures
p->vTargets = Vec_PtrAlloc( 0 );
p->vVisited = Vec_PtrAlloc( 0 );
return p;
}
/**Function*************************************************************
Synopsis [Delete manager.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Saig_BmcManStop( Saig_Bmc_t * p )
{
Aig_ManStop( p->pFrm );
Vec_PtrFree( p->vAig2Frm );
Vec_IntFree( p->vObj2Var );
sat_solver_delete( p->pSat );
Vec_PtrFree( p->vTargets );
Vec_PtrFree( p->vVisited );
free( p );
}
/**Function*************************************************************
Synopsis [Explores the possibility of constructing the output.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Aig_Obj_t * Saig_BmcIntervalExplore_rec( Saig_Bmc_t * p, Aig_Obj_t * pObj, int i )
{
Aig_Obj_t * pRes, * p0, * p1, * pConst1 = Aig_ManConst1(p->pAig);
pRes = Saig_BmcObjFrame( p, pObj, i );
if ( pRes != NULL )
return pRes;
if ( Saig_ObjIsPi( p->pAig, pObj ) )
pRes = AIG_VISITED;
else if ( Saig_ObjIsLo( p->pAig, pObj ) )
pRes = Saig_BmcIntervalExplore_rec( p, Saig_ObjLoToLi(p->pAig, pObj), i-1 );
else if ( Aig_ObjIsPo( pObj ) )
{
pRes = Saig_BmcIntervalExplore_rec( p, Aig_ObjFanin0(pObj), i );
if ( pRes != AIG_VISITED )
pRes = Saig_BmcObjChild0( p, pObj, i );
}
else
{
p0 = Saig_BmcIntervalExplore_rec( p, Aig_ObjFanin0(pObj), i );
if ( p0 != AIG_VISITED )
p0 = Saig_BmcObjChild0( p, pObj, i );
p1 = Saig_BmcIntervalExplore_rec( p, Aig_ObjFanin1(pObj), i );
if ( p1 != AIG_VISITED )
p1 = Saig_BmcObjChild1( p, pObj, i );
if ( p0 == Aig_Not(p1) )
pRes = Aig_Not(pConst1);
else if ( Aig_Regular(p0) == pConst1 )
pRes = (p0 == pConst1) ? p1 : Aig_Not(pConst1);
else if ( Aig_Regular(p1) == pConst1 )
pRes = (p1 == pConst1) ? p0 : Aig_Not(pConst1);
else
pRes = AIG_VISITED;
if ( pRes != pConst1 && pRes != Aig_Not(pConst1) )
pRes = AIG_VISITED;
}
Saig_BmcObjSetFrame( p, pObj, i, pRes );
return pRes;
}
/**Function*************************************************************
Synopsis [Performs the actual construction of the output.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Aig_Obj_t * Saig_BmcIntervalConstruct_rec( Saig_Bmc_t * p, Aig_Obj_t * pObj, int i )
{
Aig_Obj_t * pRes;
pRes = Saig_BmcObjFrame( p, pObj, i );
assert( pRes != NULL );
if ( pRes != AIG_VISITED )
return pRes;
if ( Saig_ObjIsPi( p->pAig, pObj ) )
pRes = Aig_ObjCreatePi(p->pFrm);
else if ( Saig_ObjIsLo( p->pAig, pObj ) )
pRes = Saig_BmcIntervalConstruct_rec( p, Saig_ObjLoToLi(p->pAig, pObj), i-1 );
else if ( Aig_ObjIsPo( pObj ) )
{
Saig_BmcIntervalConstruct_rec( p, Aig_ObjFanin0(pObj), i );
pRes = Saig_BmcObjChild0( p, pObj, i );
}
else
{
Saig_BmcIntervalConstruct_rec( p, Aig_ObjFanin0(pObj), i );
Saig_BmcIntervalConstruct_rec( p, Aig_ObjFanin1(pObj), i );
pRes = Aig_And( p->pFrm, Saig_BmcObjChild0(p, pObj, i), Saig_BmcObjChild1(p, pObj, i) );
}
Saig_BmcObjSetFrame( p, pObj, i, pRes );
return pRes;
}
/**Function*************************************************************
Synopsis [Adds new AIG nodes to the frames.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Saig_BmcInterval( Saig_Bmc_t * p )
{
Aig_Obj_t * pTarget, * pObj;
int i, nNodes = Aig_ManNodeNum( p->pFrm );
Vec_PtrClear( p->vTargets );
for ( ; p->iFramelast < p->nFramesMax; p->iFramelast++, p->iOutputLast = 0 )
{
if ( p->iOutputLast == 0 )
{
Saig_BmcObjSetFrame( p, Aig_ManConst1(p->pAig), p->iFramelast, Aig_ManConst1(p->pFrm) );
Saig_ManForEachPi( p->pAig, pObj, i )
Saig_BmcObjSetFrame( p, pObj, p->iFramelast, Aig_ObjCreatePi(p->pFrm) );
}
for ( ; p->iOutputLast < Saig_ManPoNum(p->pAig); p->iOutputLast++ )
{
if ( Aig_ManNodeNum(p->pFrm) >= nNodes + p->nNodesMax )
return;
Saig_BmcIntervalExplore_rec( p, Aig_ManPo(p->pAig, p->iOutputLast), p->nFramesMax );
pTarget = Saig_BmcIntervalConstruct_rec( p, Aig_ManPo(p->pAig, p->iOutputLast), p->nFramesMax );
Vec_PtrPush( p->vTargets, pTarget );
}
}
}
/**Function*************************************************************
Synopsis [Performs the actual construction of the output.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Aig_Obj_t * Saig_BmcIntervalToAig_rec( Saig_Bmc_t * p, Aig_Man_t * pNew, Aig_Obj_t * pObj )
{
if ( pObj->pData )
return pObj->pData;
Vec_PtrPush( p->vVisited, pObj );
if ( Saig_BmcSatNum(p, pObj) || Aig_ObjIsPi(pObj) )
return pObj->pData = Aig_ObjCreatePi(pNew);
Saig_BmcIntervalToAig_rec( p, pNew, Aig_ObjFanin0(pObj) );
Saig_BmcIntervalToAig_rec( p, pNew, Aig_ObjFanin1(pObj) );
return pObj->pData = Aig_And( pNew, Aig_ObjChild0Copy(pObj), Aig_ObjChild1Copy(pObj) );
}
/**Function*************************************************************
Synopsis [Creates AIG of the newly added nodes.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Aig_Man_t * Saig_BmcIntervalToAig( Saig_Bmc_t * p )
{
Aig_Man_t * pNew;
Aig_Obj_t * pObj, * pObjNew;
int i;
pNew = Aig_ManStart( p->nNodesMax );
Aig_ManConst1(p->pFrm)->pData = Aig_ManConst1(pNew);
Vec_PtrClear( p->vVisited );
Vec_PtrPush( p->vVisited, Aig_ManConst1(p->pFrm) );
Vec_PtrForEachEntry( p->vTargets, pObj, i )
{
pObjNew = Saig_BmcIntervalToAig_rec( p, pNew, Aig_Regular(pObj) );
Aig_ObjCreatePo( pNew, pObjNew );
}
return pNew;
}
/**Function*************************************************************
Synopsis [Derives CNF for the newly added nodes.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Saig_BmcLoadCnf( Saig_Bmc_t * p, Cnf_Dat_t * pCnf )
{
Aig_Obj_t * pObj, * pObjNew;
int i, Lits[2], VarNumOld, VarNumNew;
Vec_PtrForEachEntry( p->vVisited, pObj, i )
{
pObjNew = pObj->pData;
pObj->pData = NULL;
VarNumNew = pCnf->pVarNums[ pObjNew->Id ];
if ( VarNumNew == -1 )
continue;
VarNumOld = Saig_BmcSatNum( p, pObj );
if ( VarNumOld == 0 )
{
Saig_BmcSetSatNum( p, pObj, VarNumNew );
continue;
}
// add clauses connecting existing variables
Lits[0] = toLitCond( VarNumOld, 0 );
Lits[1] = toLitCond( VarNumNew, 1 );
if ( !sat_solver_addclause( p->pSat, Lits, Lits+2 ) )
assert( 0 );
Lits[0] = toLitCond( VarNumOld, 1 );
Lits[1] = toLitCond( VarNumNew, 0 );
if ( !sat_solver_addclause( p->pSat, Lits, Lits+2 ) )
assert( 0 );
}
// add CNF to the SAT solver
for ( i = 0; i < pCnf->nClauses; i++ )
if ( !sat_solver_addclause( p->pSat, pCnf->pClauses[i], pCnf->pClauses[i+1] ) )
break;
if ( i < pCnf->nClauses )
printf( "SAT solver became UNSAT after adding clauses.\n" );
}
/**Function*************************************************************
Synopsis [Solves targets with the given resource limit.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Saig_BmcSolveTargets( Saig_Bmc_t * p )
{
Aig_Obj_t * pObj;
int i, VarNum, Lit, RetValue;
assert( Vec_PtrSize(p->vTargets) > 0 );
Vec_PtrForEachEntry( p->vTargets, pObj, i )
{
if ( p->pSat->stats.conflicts > p->nConfMaxAll )
return l_Undef;
VarNum = Saig_BmcSatNum( p, Aig_Regular(pObj) );
Lit = toLitCond( VarNum, Aig_IsComplement(pObj) );
RetValue = sat_solver_solve( p->pSat, &Lit, &Lit + 1, (sint64)p->nConfMaxOne, (sint64)0, (sint64)0, (sint64)0 );
if ( RetValue == l_False ) // unsat
continue;
if ( RetValue == l_Undef ) // undecided
return l_Undef;
// generate counter-example
return l_True;
}
return l_False;
}
/**Function*************************************************************
Synopsis [Performs BMC with the given parameters.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Saig_BmcPerform( Aig_Man_t * pAig, int nConfMaxOne, int nConfMaxAll, int nNodesMax, int fVerbose )
{
Saig_Bmc_t * p;
Aig_Man_t * pNew;
Cnf_Dat_t * pCnf;
int RetValue, clk = clock();
p = Saig_BmcManStart( pAig, nConfMaxOne, nConfMaxAll, nNodesMax, fVerbose );
while ( 1 )
{
// add new logic slice to frames
Saig_BmcInterval( p );
if ( Vec_PtrSize(p->vTargets) == 0 )
break;
// convert logic slice into new AIG
pNew = Saig_BmcIntervalToAig( p );
// derive CNF for the new AIG
pCnf = Cnf_Derive( pNew, Aig_ManPoNum(pNew) );
Cnf_DataLift( pCnf, p->nSatVars );
p->nSatVars += pCnf->nVars;
// add this CNF to the solver
Saig_BmcLoadCnf( p, pCnf );
Cnf_DataFree( pCnf );
Aig_ManStop( pNew );
// solve the targets
RetValue = Saig_BmcSolveTargets( p );
if ( RetValue != l_False )
break;
}
if ( RetValue == l_True )
printf( "BMC failed for output %d in frame %d. ", p->iOutputLast, p->iFramelast );
else // if ( RetValue == l_False || RetValue == l_Undef )
printf( "BMC completed for %d timeframes. ", p->iFramelast );
PRT( "Time", clock() - clk );
if ( p->iFramelast >= p->nFramesMax )
printf( "Reached limit on the number of timeframes (%d).\n", p->nFramesMax );
else if ( p->pSat->stats.conflicts > p->nConfMaxAll )
printf( "Reached global conflict limit (%d).\n", p->nConfMaxAll );
else
printf( "Reached local conflict limit (%d).\n", p->nConfMaxOne );
Saig_BmcManStop( p );
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
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