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/**CFile****************************************************************
FileName [saigAbsPba.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [Sequential AIG package.]
Synopsis [Proof-based abstraction.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - June 20, 2005.]
Revision [$Id: saigAbsPba.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]
***********************************************************************/
#include "saig.h"
#include "cnf.h"
#include "satSolver.h"
#include "giaAig.h"
ABC_NAMESPACE_IMPL_START
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Collect nodes in the unrolled timeframes.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Saig_ManUnrollForPba_rec( Aig_Man_t * pAig, Aig_Obj_t * pObj, Vec_Int_t * vObjs, Vec_Int_t * vRoots )
{
if ( Aig_ObjIsTravIdCurrent(pAig, pObj) )
return;
Aig_ObjSetTravIdCurrent(pAig, pObj);
if ( Aig_ObjIsPo(pObj) )
Saig_ManUnrollForPba_rec( pAig, Aig_ObjFanin0(pObj), vObjs, vRoots );
else if ( Aig_ObjIsNode(pObj) )
{
Saig_ManUnrollForPba_rec( pAig, Aig_ObjFanin0(pObj), vObjs, vRoots );
Saig_ManUnrollForPba_rec( pAig, Aig_ObjFanin1(pObj), vObjs, vRoots );
}
if ( vRoots && Saig_ObjIsLo( pAig, pObj ) )
Vec_IntPush( vRoots, Aig_ObjId( Saig_ObjLoToLi(pAig, pObj) ) );
Vec_IntPush( vObjs, Aig_ObjId(pObj) );
}
/**Function*************************************************************
Synopsis [Derives unrolled timeframes for PBA.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Aig_Man_t * Saig_ManUnrollForPba( Aig_Man_t * pAig, int nStart, int nFrames, Vec_Int_t ** pvPiVarMap )
{
Aig_Man_t * pFrames; // unrolled timeframes
Vec_Vec_t * vFrameCos; // the list of COs per frame
Vec_Vec_t * vFrameObjs; // the list of objects per frame
Vec_Int_t * vRoots, * vObjs;
Aig_Obj_t * pObj, * pObjNew;
int i, f;
assert( nStart <= nFrames );
// collect COs and Objs visited in each frame
vFrameCos = Vec_VecStart( nFrames );
vFrameObjs = Vec_VecStart( nFrames );
for ( f = nFrames-1; f >= 0; f-- )
{
// add POs of this frame
vRoots = Vec_VecEntryInt( vFrameCos, f );
Saig_ManForEachPo( pAig, pObj, i )
Vec_IntPush( vRoots, Aig_ObjId(pObj) );
// collect nodes starting from the roots
Aig_ManIncrementTravId( pAig );
Aig_ManForEachObjVec( vRoots, pAig, pObj, i )
Saig_ManUnrollForPba_rec( pAig, pObj,
Vec_VecEntryInt( vFrameObjs, f ),
(Vec_Int_t *)(f ? Vec_VecEntry(vFrameCos, f-1) : NULL) );
}
// derive unrolled timeframes
pFrames = Aig_ManStart( 10000 );
pFrames->pName = Aig_UtilStrsav( pAig->pName );
pFrames->pSpec = Aig_UtilStrsav( pAig->pSpec );
// create activation variables
Saig_ManForEachLo( pAig, pObj, i )
Aig_ObjCreatePi( pFrames );
// initialize the flops
Saig_ManForEachLo( pAig, pObj, i )
pObj->pData = Aig_Mux( pFrames, Aig_ManPi(pFrames,i), Aig_ObjCreatePi(pFrames), Aig_ManConst0(pFrames) );
// iterate through the frames
*pvPiVarMap = Vec_IntStartFull( nFrames * Saig_ManPiNum(pAig) );
pObjNew = Aig_ManConst0(pFrames);
for ( f = 0; f < nFrames; f++ )
{
// construct
vObjs = Vec_VecEntryInt( vFrameObjs, f );
Aig_ManForEachObjVec( vObjs, pAig, pObj, i )
{
if ( Aig_ObjIsNode(pObj) )
pObj->pData = Aig_And( pFrames, Aig_ObjChild0Copy(pObj), Aig_ObjChild1Copy(pObj) );
else if ( Aig_ObjIsPo(pObj) )
pObj->pData = Aig_ObjChild0Copy(pObj);
else if ( Saig_ObjIsPi(pAig, pObj) )
{
Vec_IntWriteEntry( *pvPiVarMap, f * Saig_ManPiNum(pAig) + Aig_ObjPioNum(pObj), Aig_ManPiNum(pFrames) );
pObj->pData = Aig_ObjCreatePi( pFrames );
}
else if ( Aig_ObjIsConst1(pObj) )
pObj->pData = Aig_ManConst1(pFrames);
else if ( !Saig_ObjIsLo(pAig, pObj) )
assert( 0 );
}
// create output
if ( f >= nStart )
{
Saig_ManForEachPo( pAig, pObj, i )
pObjNew = Aig_Or( pFrames, pObjNew, pObj->pData );
}
// transfer
if ( f == nFrames - 1 )
break;
vRoots = Vec_VecEntryInt( vFrameCos, f );
Aig_ManForEachObjVec( vRoots, pAig, pObj, i )
{
if ( Saig_ObjIsLi(pAig, pObj) )
{
int iFlopNum = Aig_ObjPioNum(pObj) - Saig_ManPoNum(pAig);
assert( iFlopNum >= 0 && iFlopNum < Aig_ManRegNum(pAig) );
Saig_ObjLiToLo(pAig, pObj)->pData = Aig_Mux( pFrames, Aig_ManPi(pFrames,iFlopNum), Aig_ObjCreatePi(pFrames), pObj->pData );
}
}
}
// cleanup
Vec_VecFree( vFrameCos );
Vec_VecFree( vFrameObjs );
// create output
Aig_ObjCreatePo( pFrames, pObjNew );
Aig_ManSetRegNum( pFrames, 0 );
// finallize
Aig_ManCleanup( pFrames );
return pFrames;
}
/**Function*************************************************************
Synopsis [Derives the counter-example from the SAT solver.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Abc_Cex_t * Saig_ManPbaDeriveCex( Aig_Man_t * pAig, sat_solver * pSat, Cnf_Dat_t * pCnf, int nFrames, Vec_Int_t * vPiVarMap )
{
Abc_Cex_t * pCex;
Aig_Obj_t * pObj, * pObjRi, * pObjRo;
int i, f, Entry, iBit = 0;
pCex = Abc_CexAlloc( Aig_ManRegNum(pAig), Saig_ManPiNum(pAig), nFrames );
pCex->iPo = -1;
pCex->iFrame = -1;
Vec_IntForEachEntry( vPiVarMap, Entry, i )
{
if ( Entry >= 0 )
{
int iSatVar = pCnf->pVarNums[ Aig_ObjId(Aig_ManPi(pCnf->pMan, Entry)) ];
if ( sat_solver_var_value( pSat, iSatVar ) )
Aig_InfoSetBit( pCex->pData, Aig_ManRegNum(pAig) + i );
}
}
// check what frame has failed
Aig_ManCleanMarkB(pAig);
Aig_ManConst1(pAig)->fMarkB = 1;
Saig_ManForEachLo( pAig, pObj, i )
pObj->fMarkB = Aig_InfoHasBit(pCex->pData, iBit++);
for ( f = 0; f < nFrames; f++ )
{
// compute new state
Saig_ManForEachPi( pAig, pObj, i )
pObj->fMarkB = Aig_InfoHasBit(pCex->pData, iBit++);
Aig_ManForEachNode( pAig, pObj, i )
pObj->fMarkB = (Aig_ObjFanin0(pObj)->fMarkB ^ Aig_ObjFaninC0(pObj)) &
(Aig_ObjFanin1(pObj)->fMarkB ^ Aig_ObjFaninC1(pObj));
Aig_ManForEachPo( pAig, pObj, i )
pObj->fMarkB = Aig_ObjFanin0(pObj)->fMarkB ^ Aig_ObjFaninC0(pObj);
Saig_ManForEachLiLo( pAig, pObjRi, pObjRo, i )
pObjRo->fMarkB = pObjRi->fMarkB;
// check the outputs
Saig_ManForEachPo( pAig, pObj, i )
{
if ( pObj->fMarkB )
{
pCex->iPo = i;
pCex->iFrame = f;
pCex->nBits = pCex->nRegs + pCex->nPis * (f+1);
break;
}
}
if ( i < Saig_ManPoNum(pAig) )
break;
}
Aig_ManCleanMarkB(pAig);
if ( f == nFrames )
{
Abc_Print( -1, "Saig_ManPbaDeriveCex(): Internal error! Cannot find a failed primary outputs.\n" );
Abc_CexFree( pCex );
pCex = NULL;
}
if ( !Saig_ManVerifyCex( pAig, pCex ) )
{
Abc_Print( -1, "Saig_ManPbaDeriveCex(): Internal error! Counter-example is invalid.\n" );
Abc_CexFree( pCex );
pCex = NULL;
}
return pCex;
}
/**Function*************************************************************
Synopsis [Derive unrolled timeframes.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Vec_Int_t * Saig_ManPbaDerive( Aig_Man_t * pAig, int nInputs, int nStart, int nFrames, int nConfLimit, int fVerbose, int * piFrame )
{
Vec_Int_t * vFlops = NULL, * vMapVar2FF, * vAssumps, * vPiVarMap;
Aig_Man_t * pFrames;
sat_solver * pSat;
Cnf_Dat_t * pCnf;
Aig_Obj_t * pObj;
int nCoreLits, * pCoreLits;
int i, iVar, RetValue, clk;
if ( fVerbose )
printf( "Performing abstraction with starting frame %d and total number of frames %d.\n", nStart, nFrames );
// create SAT solver
clk = clock();
pFrames = Saig_ManUnrollForPba( pAig, nStart, nFrames, &vPiVarMap );
if ( fVerbose )
Aig_ManPrintStats( pFrames );
// pCnf = Cnf_DeriveSimple( pFrames, 0 );
pCnf = Cnf_Derive( pFrames, 0 );
pSat = (sat_solver *)Cnf_DataWriteIntoSolver( pCnf, 1, 0 );
if ( pSat == NULL )
{
Aig_ManStop( pFrames );
Cnf_DataFree( pCnf );
return NULL;
}
if ( fVerbose )
Abc_PrintTime( 1, "Preparing", clock() - clk );
// map activation variables into flop numbers
vAssumps = Vec_IntAlloc( Aig_ManRegNum(pAig) );
vMapVar2FF = Vec_IntStartFull( pCnf->nVars );
Aig_ManForEachPi( pFrames, pObj, i )
{
if ( i >= Aig_ManRegNum(pAig) )
break;
iVar = pCnf->pVarNums[Aig_ObjId(pObj)];
Vec_IntPush( vAssumps, toLitCond(iVar, 1) );
Vec_IntWriteEntry( vMapVar2FF, iVar, i );
}
// run SAT solver
clk = clock();
RetValue = sat_solver_solve( pSat, Vec_IntArray(vAssumps), Vec_IntArray(vAssumps) + Vec_IntSize(vAssumps),
(ABC_INT64_T)nConfLimit, (ABC_INT64_T)0, (ABC_INT64_T)0, (ABC_INT64_T)0 );
if ( fVerbose )
Abc_PrintTime( 1, "Solving", clock() - clk );
if ( RetValue != l_False )
{
if ( RetValue == l_True )
{
Vec_Int_t * vAbsFfsToAdd;
ABC_FREE( pAig->pSeqModel );
pAig->pSeqModel = Saig_ManPbaDeriveCex( pAig, pSat, pCnf, nFrames, vPiVarMap );
printf( "The problem is SAT in frame %d. Performing CEX-based refinement.\n", pAig->pSeqModel->iFrame );
*piFrame = pAig->pSeqModel->iFrame;
// CEX is detected - refine the flops
vAbsFfsToAdd = Saig_ManCbaFilterInputs( pAig, nInputs, pAig->pSeqModel, fVerbose );
if ( Vec_IntSize(vAbsFfsToAdd) == 0 )
{
Vec_IntFree( vAbsFfsToAdd );
goto finish;
}
if ( fVerbose )
{
printf( "Adding %d registers to the abstraction (total = %d). ", Vec_IntSize(vAbsFfsToAdd), Aig_ManRegNum(pAig)+Vec_IntSize(vAbsFfsToAdd) );
Abc_PrintTime( 1, "Time", clock() - clk );
}
vFlops = vAbsFfsToAdd;
}
else
{
printf( "Saig_ManPerformPba(): SAT solver timed out. Current abstraction is not changed.\n" );
}
goto finish;
}
assert( RetValue == l_False ); // UNSAT
*piFrame = nFrames;
// get relevant SAT literals
nCoreLits = sat_solver_final( pSat, &pCoreLits );
assert( nCoreLits > 0 );
if ( fVerbose )
printf( "AnalizeFinal after %d frames selected %d assumptions (out of %d). Conflicts = %d.\n",
nFrames, nCoreLits, Vec_IntSize(vAssumps), (int)pSat->stats.conflicts );
// collect flops
vFlops = Vec_IntAlloc( nCoreLits );
for ( i = 0; i < nCoreLits; i++ )
{
iVar = Vec_IntEntry( vMapVar2FF, lit_var(pCoreLits[i]) );
assert( iVar >= 0 && iVar < Aig_ManRegNum(pAig) );
Vec_IntPush( vFlops, iVar );
}
Vec_IntSort( vFlops, 0 );
// cleanup
finish:
Vec_IntFree( vPiVarMap );
Vec_IntFree( vAssumps );
Vec_IntFree( vMapVar2FF );
sat_solver_delete( pSat );
Cnf_DataFree( pCnf );
Aig_ManStop( pFrames );
return vFlops;
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
ABC_NAMESPACE_IMPL_END
|
