mirror of https://github.com/YosysHQ/abc.git
Backward reachability using circuit cofactoring.
This commit is contained in:
Alan Mishchenko
parent
aec5d33889
commit
e3a412b2e7
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/**CFile****************************************************************
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FileName [giaCCof.c]
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SystemName [ABC: Logic synthesis and verification system.]
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PackageName [Scalable AIG package.]
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Synopsis [Backward reachability using circuit cofactoring.]
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Author [Alan Mishchenko]
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Affiliation [UC Berkeley]
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Date [Ver. 1.0. Started - June 20, 2005.]
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Revision [$Id: giaCCof.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]
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***********************************************************************/
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#include "gia.h"
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#include "satSolver.h"
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ABC_NAMESPACE_IMPL_START
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////////////////////////////////////////////////////////////////////////
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/// DECLARATIONS ///
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////////////////////////////////////////////////////////////////////////
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typedef struct Ccf_Man_t_ Ccf_Man_t; // manager
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struct Ccf_Man_t_
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{
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// user data
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Gia_Man_t * pGia; // single output AIG manager
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int nFrameMax; // maximum number of frames
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int nConfMax; // maximum number of conflicts
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int nTimeMax; // maximum runtime in seconds
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int fVerbose; // verbose flag
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// internal data
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sat_solver * pSat; // SAT solver
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Gia_Man_t * pFrames; // unrolled timeframes
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Vec_Int_t * vIdToFra; // maps GIA obj IDs into frame obj IDs
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Vec_Int_t * vOrder; // map Num to Id
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Vec_Int_t * vFraLims; // frame limits
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};
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extern Vec_Int_t * Gia_VtaCollect( Gia_Man_t * p, Vec_Int_t ** pvFraLims, Vec_Int_t ** pvRoots );
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static inline int Gia_ObjFrames( Ccf_Man_t * p, int f, Gia_Obj_t * pObj ) { assert( Vec_IntEntry(p->vIdToFra, f*Gia_ManObjNum(p->pGia)+Gia_ObjId(p->pGia,pObj)) >= 0 ); return Vec_IntEntry(p->vIdToFra, f*Gia_ManObjNum(p->pGia)+Gia_ObjId(p->pGia,pObj)); }
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static inline void Gia_ObjSetFrames( Ccf_Man_t * p, int f, Gia_Obj_t * pObj, int Lit ) { Vec_IntWriteEntry(p->vIdToFra, f*Gia_ManObjNum(p->pGia)+Gia_ObjId(p->pGia,pObj), Lit); }
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static inline int Gia_ObjChild0Frames( Ccf_Man_t * p, int f, Gia_Obj_t * pObj ) { return Gia_LitNotCond(Gia_ObjFrames(p, f, Gia_ObjFanin0(pObj)), Gia_ObjFaninC0(pObj)); }
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static inline int Gia_ObjChild1Frames( Ccf_Man_t * p, int f, Gia_Obj_t * pObj ) { return Gia_LitNotCond(Gia_ObjFrames(p, f, Gia_ObjFanin1(pObj)), Gia_ObjFaninC1(pObj)); }
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////////////////////////////////////////////////////////////////////////
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/// FUNCTION DEFINITIONS ///
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////////////////////////////////////////////////////////////////////////
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static inline int sat_solver_add_const( sat_solver * pSat, int iVar, int fCompl )
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{
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lit Lits[1];
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int Cid;
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assert( iVar >= 0 );
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Lits[0] = toLitCond( iVar, fCompl );
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Cid = sat_solver_addclause( pSat, Lits, Lits + 1 );
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assert( Cid );
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return 1;
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}
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static inline int sat_solver_add_buffer( sat_solver * pSat, int iVarA, int iVarB, int fCompl )
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{
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lit Lits[2];
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int Cid;
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assert( iVarA >= 0 && iVarB >= 0 );
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Lits[0] = toLitCond( iVarA, 0 );
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Lits[1] = toLitCond( iVarB, !fCompl );
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Cid = sat_solver_addclause( pSat, Lits, Lits + 2 );
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assert( Cid );
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Lits[0] = toLitCond( iVarA, 1 );
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Lits[1] = toLitCond( iVarB, fCompl );
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Cid = sat_solver_addclause( pSat, Lits, Lits + 2 );
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assert( Cid );
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return 2;
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}
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static inline int sat_solver_add_and( sat_solver * pSat, int iVar, int iVar0, int iVar1, int fCompl0, int fCompl1 )
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{
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lit Lits[3];
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int Cid;
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Lits[0] = toLitCond( iVar, 1 );
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Lits[1] = toLitCond( iVar0, fCompl0 );
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Cid = sat_solver_addclause( pSat, Lits, Lits + 2 );
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assert( Cid );
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Lits[0] = toLitCond( iVar, 1 );
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Lits[1] = toLitCond( iVar1, fCompl1 );
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Cid = sat_solver_addclause( pSat, Lits, Lits + 2 );
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assert( Cid );
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Lits[0] = toLitCond( iVar, 0 );
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Lits[1] = toLitCond( iVar0, !fCompl0 );
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Lits[2] = toLitCond( iVar1, !fCompl1 );
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Cid = sat_solver_addclause( pSat, Lits, Lits + 3 );
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assert( Cid );
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return 3;
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}
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static inline int sat_solver_add_xor( sat_solver * pSat, int iVarA, int iVarB, int iVarC, int fCompl )
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{
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lit Lits[3];
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int Cid;
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assert( iVarA >= 0 && iVarB >= 0 && iVarC >= 0 );
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Lits[0] = toLitCond( iVarA, !fCompl );
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Lits[1] = toLitCond( iVarB, 1 );
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Lits[2] = toLitCond( iVarC, 1 );
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Cid = sat_solver_addclause( pSat, Lits, Lits + 3 );
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assert( Cid );
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Lits[0] = toLitCond( iVarA, !fCompl );
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Lits[1] = toLitCond( iVarB, 0 );
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Lits[2] = toLitCond( iVarC, 0 );
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Cid = sat_solver_addclause( pSat, Lits, Lits + 3 );
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assert( Cid );
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Lits[0] = toLitCond( iVarA, fCompl );
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Lits[1] = toLitCond( iVarB, 1 );
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Lits[2] = toLitCond( iVarC, 0 );
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Cid = sat_solver_addclause( pSat, Lits, Lits + 3 );
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assert( Cid );
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Lits[0] = toLitCond( iVarA, fCompl );
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Lits[1] = toLitCond( iVarB, 0 );
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Lits[2] = toLitCond( iVarC, 1 );
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Cid = sat_solver_addclause( pSat, Lits, Lits + 3 );
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assert( Cid );
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return 4;
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}
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static inline int sat_solver_add_constraint( sat_solver * pSat, int iVar, int fCompl )
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{
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lit Lits[2];
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int Cid;
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assert( iVar >= 0 );
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Lits[0] = toLitCond( iVar, fCompl );
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Lits[1] = toLitCond( iVar+1, 0 );
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Cid = sat_solver_addclause( pSat, Lits, Lits + 2 );
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assert( Cid );
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Lits[0] = toLitCond( iVar, fCompl );
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Lits[1] = toLitCond( iVar+1, 1 );
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Cid = sat_solver_addclause( pSat, Lits, Lits + 2 );
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assert( Cid );
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return 2;
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}
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/**Function*************************************************************
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Synopsis [Create manager.]
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Description []
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SideEffects []
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SeeAlso []
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***********************************************************************/
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Ccf_Man_t * Ccf_ManStart( Gia_Man_t * pGia, int nFrameMax, int nConfMax, int nTimeMax, int fVerbose )
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{
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Ccf_Man_t * p;
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assert( nFrameMax > 0 );
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p = ABC_CALLOC( Ccf_Man_t, 1 );
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p->pGia = pGia;
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p->nFrameMax = nFrameMax;
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p->nConfMax = nConfMax;
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p->nTimeMax = nTimeMax;
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p->fVerbose = fVerbose;
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// internal data
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p->pFrames = Gia_ManStart( 10000 );
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Gia_ManHashAlloc( p->pFrames );
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p->vOrder = Gia_VtaCollect( pGia, &p->vFraLims, NULL );
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p->vIdToFra = Vec_IntAlloc( 0 );
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p->pSat = sat_solver_new();
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sat_solver_setnvars( p->pSat, 10000 );
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return p;
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}
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/**Function*************************************************************
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Synopsis [Delete manager.]
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Description []
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SideEffects []
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SeeAlso []
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***********************************************************************/
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void Ccf_ManStop( Ccf_Man_t * p )
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{
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Vec_IntFreeP( &p->vIdToFra );
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Vec_IntFreeP( &p->vOrder );
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Vec_IntFreeP( &p->vFraLims );
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sat_solver_delete( p->pSat );
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Gia_ManStopP( &p->pFrames );
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ABC_FREE( p );
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}
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/**Function*************************************************************
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Synopsis [Extends the solver.]
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Description []
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SideEffects []
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SeeAlso []
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***********************************************************************/
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void Gia_ManCofExtendSolver( Ccf_Man_t * p )
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{
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Gia_Obj_t * pObj;
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int i;
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// add SAT clauses
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for ( i = sat_solver_nvars(p->pSat); i < Gia_ManObjNum(p->pFrames); i++ )
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{
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pObj = Gia_ManObj( p->pGia, i );
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if ( Gia_ObjIsAnd(pObj) )
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sat_solver_add_and( p->pSat, i,
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Gia_ObjFaninId0(pObj, i),
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Gia_ObjFaninId1(pObj, i),
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Gia_ObjFaninC0(pObj),
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Gia_ObjFaninC1(pObj) );
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}
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}
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/**Function*************************************************************
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Synopsis [Adds logic of one timeframe to the manager.]
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Description [Returns literal of the property output.]
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SideEffects []
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SeeAlso []
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***********************************************************************/
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int Gia_ManCofAddTimeFrame( Ccf_Man_t * p, int fMax )
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{
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Gia_Obj_t * pObj;
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int i, f, Beg, End, Lit;
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assert( fMax > 0 && fMax <= p->nFrameMax );
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assert( Vec_IntSize(p->vIdToFra) == (fMax - 1) * Gia_ManObjNum(p->pGia) );
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// add to the mapping of nodes
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Vec_IntFillExtra( p->vIdToFra, fMax * Gia_ManObjNum(p->pGia), -1 );
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// add nodes to each time-frame
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for ( f = 0; f < fMax; f++ )
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{
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if ( Vec_IntSize(p->vFraLims) >= fMax-f )
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continue;
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Beg = Vec_IntEntry( p->vFraLims, fMax-f-1 );
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End = Vec_IntEntry( p->vFraLims, fMax-f );
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for ( i = Beg; i < End; i++ )
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{
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pObj = Gia_ManObj( p->pGia, Vec_IntEntry(p->vOrder, i) );
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if ( Gia_ObjIsAnd(pObj) )
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Lit = Gia_ManHashAnd( p->pFrames, Gia_ObjChild0Frames(p, f, pObj), Gia_ObjChild1Frames(p, f, pObj) );
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else if ( Gia_ObjIsRo(p->pGia, pObj) && f > 0 )
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Lit = Gia_ObjChild0Frames(p, f-1, Gia_ObjRoToRi(p->pGia, pObj));
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else if ( Gia_ObjIsCi(pObj) )
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{
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Lit = Gia_ManAppendCi(p->pFrames);
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// mark primary input
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Gia_ManObj(p->pFrames, Gia_Lit2Var(Lit))->fMark0 = Gia_ObjIsPi(p->pGia, pObj);
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}
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else assert( 0 );
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Gia_ObjSetFrames( p, f, pObj, Lit );
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}
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}
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// add SAT clauses
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Gia_ManCofExtendSolver( p );
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// return output literal
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return Gia_ObjChild0Frames( p, fMax-1, Gia_ManPo(p->pGia, 0) );
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}
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/**Function*************************************************************
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Synopsis [Cofactor the circuit w.r.t. the given assignment.]
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Description [Assumes that the solver has just returned SAT.]
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SideEffects []
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SeeAlso []
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***********************************************************************/
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int Gia_ManCofOneDerive_rec( Ccf_Man_t * p, Gia_Obj_t * pObj )
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{
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if ( ~pObj->Value )
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return pObj->Value;
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assert( Gia_ObjIsCi(pObj) || Gia_ObjIsAnd(pObj) );
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if ( Gia_ObjIsAnd(pObj) )
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{
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Gia_ManCofOneDerive_rec( p, Gia_ObjFanin0(pObj) );
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Gia_ManCofOneDerive_rec( p, Gia_ObjFanin1(pObj) );
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pObj->Value = Gia_ManHashAnd( p->pFrames, Gia_ObjFanin0Copy(pObj), Gia_ObjFanin1Copy(pObj) );
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}
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else if ( pObj->fMark0 ) // PI
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pObj->Value = sat_solver_var_value( p->pSat, Gia_ObjId(p->pGia, pObj) );
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else
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pObj->Value = Gia_Var2Lit( Gia_ObjId(p->pGia, pObj), 0 );
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return pObj->Value;
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}
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/**Function*************************************************************
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Synopsis [Cofactor the circuit w.r.t. the given assignment.]
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Description [Assumes that the solver has just returned SAT.]
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SideEffects []
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SeeAlso []
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***********************************************************************/
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int Gia_ManCofOneDerive( Ccf_Man_t * p, int LitProp )
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{
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Gia_Obj_t * pObj;
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int LitOut;
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// get the property node
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pObj = Gia_ManObj( p->pFrames, Gia_Lit2Var(LitProp) );
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// derive the cofactor
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Gia_ManFillValue( p->pFrames );
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LitOut = Gia_ManCofOneDerive_rec( p, pObj );
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LitOut = Gia_LitNotCond(LitOut, Gia_LitIsCompl(LitProp));
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// add new PO for the cofactor
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Gia_ManAppendCo( p->pFrames, LitOut );
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// add SAT clauses
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Gia_ManCofExtendSolver( p );
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// return negative literal of the cofactor
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return Gia_LitNot(LitOut);
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}
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/**Function*************************************************************
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Synopsis [Enumerates backward reachable states.]
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Description [Return -1 if resource limit is reached. Returns 1
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if computation converged (there is no more reachable states).
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Returns 0 if no more states to enumerate.]
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SideEffects []
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SeeAlso []
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***********************************************************************/
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int Gia_ManCofGetReachable( Ccf_Man_t * p, int Lit )
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{
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int RetValue;
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// try solving for the first time and quit if converged
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RetValue = sat_solver_solve( p->pSat, &Lit, &Lit + 1, p->nConfMax, 0, 0, 0 );
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if ( RetValue == l_False )
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return 1;
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// iterate circuit cofactoring
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while ( RetValue == 0 )
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{
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// derive cofactor
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int LitOut = Gia_ManCofOneDerive( p, Lit );
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// add the blocking clause
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RetValue = sat_solver_addclause( p->pSat, &LitOut, &LitOut + 1 );
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assert( RetValue );
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// try solving again
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RetValue = sat_solver_solve( p->pSat, &Lit, &Lit + 1, p->nConfMax, 0, 0, 0 );
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}
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if ( RetValue == l_Undef )
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return -1;
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return 0;
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}
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/**Function*************************************************************
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Synopsis []
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Description []
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SideEffects []
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SeeAlso []
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***********************************************************************/
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Gia_Man_t * Gia_ManCofTest( Gia_Man_t * pGia, int nFrameMax, int nConfMax, int nTimeMax, int fVerbose )
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{
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Gia_Man_t * pNew;
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Ccf_Man_t * p;
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int f, Lit, RetValue;
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assert( Gia_ManPoNum(pGia) == 1 );
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// create reachability manager
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p = Ccf_ManStart( pGia, nFrameMax, nConfMax, nTimeMax, fVerbose );
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// perform backward image computation
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for ( f = 0; f < nFrameMax; f++ )
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{
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if ( fVerbose )
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printf( "ITER %3d :\n", f );
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// derives new timeframe and returns the property literal
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Lit = Gia_ManCofAddTimeFrame( p, f+1 );
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// derives cofactors of the property literal till all states are blocked
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RetValue = Gia_ManCofGetReachable( p, Lit );
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if ( RetValue )
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break;
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}
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// report the result
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if ( f == nFrameMax )
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printf( "Completed %d frames without converging.\n", f );
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else if ( RetValue == 1 )
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printf( "Backward reachability converged after %d iterations.\n", f );
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else if ( RetValue == -1 )
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printf( "Conflict limit or timeout is reached after %d frames.\n", f );
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// get the resulting AIG manager
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Gia_ManHashStop( p->pFrames );
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Gia_ManCleanMark0( p->pFrames );
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pNew = p->pFrames; p->pFrames = NULL;
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Ccf_ManStop( p );
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pNew = Gia_ManCleanup( pGia = pNew );
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Gia_ManStop( pGia );
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// if ( fVerbose )
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Gia_ManPrintStats( pNew, 0 );
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return pNew;
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}
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////////////////////////////////////////////////////////////////////////
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/// END OF FILE ///
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////////////////////////////////////////////////////////////////////////
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ABC_NAMESPACE_IMPL_END
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