text: /*++
  Copyright (c) 2012 Microsoft Corporation
  
  Module Name:
  
      fpa2bv_rewriter.cpp
  
  Abstract:
  
      Rewriter for converting FPA to BV
  
  Author:
  
      Christoph (cwinter) 2012-02-09
  
  Notes:
  
  --*/
  
  
  #include "ast/rewriter/rewriter_def.h"
  #include "ast/fpa/fpa2bv_rewriter.h"
  #include "util/cooperate.h"
  #include "ast/fpa/fpa2bv_rewriter_params.hpp"
  
  
  fpa2bv_rewriter_cfg::fpa2bv_rewriter_cfg(ast_manager & m, fpa2bv_converter & c, params_ref const & p) :
      m_manager(m),
      m_out(m),
      m_conv(c),
      m_bindings(m)
  {
      updt_params(p);
      // We need to make sure that the mananger has the BV plugin loaded.
      symbol s_bv("bv");
      if (!m_manager.has_plugin(s_bv))
          m_manager.register_plugin(s_bv, alloc(bv_decl_plugin));
  }
  
  void fpa2bv_rewriter_cfg::updt_local_params(params_ref const & _p) {
      fpa2bv_rewriter_params p(_p);
      bool v = p.hi_fp_unspecified();
      m_conv.set_unspecified_fp_hi(v);
  }
  
  void fpa2bv_rewriter_cfg::updt_params(params_ref const & p) {
      m_max_memory        = megabytes_to_bytes(p.get_uint("max_memory", UINT_MAX));
      m_max_steps         = p.get_uint("max_steps", UINT_MAX);
      updt_local_params(p);
  }
  
  bool fpa2bv_rewriter_cfg::max_steps_exceeded(unsigned num_steps) const {
      cooperate("fpa2bv");
      return num_steps > m_max_steps;
  }
  
  
  br_status fpa2bv_rewriter_cfg::reduce_app(func_decl * f, unsigned num, expr * const * args, expr_ref & result, proof_ref & result_pr) {
      TRACE("fpa2bv_rw", tout << "func: " << f->get_name() << std::endl;
                         tout << "args: " << std::endl;
                         for (unsigned i = 0; i < num; i++)
                             tout << mk_ismt2_pp(args[i], m()) << std::endl;);
  
      if (num == 0 && f->get_family_id() == null_family_id && m_conv.is_float(f->get_range())) {
          m_conv.mk_const(f, result);
          return BR_DONE;
      }
  
      if (num == 0 && f->get_family_id() == null_family_id && m_conv.is_rm(f->get_range())) {
          m_conv.mk_rm_const(f, result);
          return BR_DONE;
      }
  
      if (m().is_eq(f)) {
          SASSERT(num == 2);
          TRACE("fpa2bv_rw", tout << "(= " << mk_ismt2_pp(args[0], m()) << " " <<
              mk_ismt2_pp(args[1], m()) << ")" << std::endl;);
          SASSERT(m().get_sort(args[0]) == m().get_sort(args[1]));
          sort * ds = f->get_domain()[0];
          if (m_conv.is_float(ds)) {
              m_conv.mk_eq(args[0], args[1], result);
              return BR_DONE;
          }
          else if (m_conv.is_rm(ds)) {
              result = m().mk_eq(args[0], args[1]);
              return BR_DONE;
          }
          return BR_FAILED;
      }
      else if (m().is_ite(f)) {
          SASSERT(num == 3);
          if (m_conv.is_float(args[1]) || m_conv.is_rm(args[1])) {
              m_conv.mk_ite(args[0], args[1], args[2], result);
              return BR_DONE;
          }
          return BR_FAILED;
      }
      else if (m().is_distinct(f)) {
          sort * ds = f->get_domain()[0];
          if (m_conv.is_float(ds) || m_conv.is_rm(ds)) {
              m_conv.mk_distinct(f, num, args, result);
              return BR_DONE;
          }
          return BR_FAILED;
      }
  
      if (m_conv.is_float_family(f)) {
          switch (f->get_decl_kind()) {
          case OP_FPA_RM_NEAREST_TIES_TO_AWAY:
          case OP_FPA_RM_NEAREST_TIES_TO_EVEN:
          case OP_FPA_RM_TOWARD_NEGATIVE:
          case OP_FPA_RM_TOWARD_POSITIVE:
          case OP_FPA_RM_TOWARD_ZERO: m_conv.mk_rounding_mode(f->get_decl_kind(), result); return BR_DONE;
          case OP_FPA_NUM: m_conv.mk_numeral(f, num, args, result); return BR_DONE;
          case OP_FPA_PLUS_INF: m_conv.mk_pinf(f, result); return BR_DONE;
          case OP_FPA_MINUS_INF: m_conv.mk_ninf(f, result); return BR_DONE;
          case OP_FPA_PLUS_ZERO: m_conv.mk_pzero(f, result); return BR_DONE;
          case OP_FPA_MINUS_ZERO: m_conv.mk_nzero(f, result); return BR_DONE;
          case OP_FPA_NAN: m_conv.mk_nan(f, result); return BR_DONE;
          case OP_FPA_ADD: m_conv.mk_add(f, num, args, result); return BR_DONE;
          case OP_FPA_SUB: m_conv.mk_sub(f, num, args, result); return BR_DONE;
          case OP_FPA_NEG: m_conv.mk_neg(f, num, args, result); return BR_DONE;
          case OP_FPA_MUL: m_conv.mk_mul(f, num, args, result); return BR_DONE;
          case OP_FPA_DIV: m_conv.mk_div(f, num, args, result); return BR_DONE;
          case OP_FPA_REM: m_conv.mk_rem(f, num, args, result); return BR_DONE;
          case OP_FPA_ABS: m_conv.mk_abs(f, num, args, result); return BR_DONE;
          case OP_FPA_MIN: m_conv.mk_min(f, num, args, result); return BR_DONE;
          case OP_FPA_MAX: m_conv.mk_max(f, num, args, result); return BR_DONE;
          case OP_FPA_FMA: m_conv.mk_fma(f, num, args, result); return BR_DONE;
          case OP_FPA_SQRT: m_conv.mk_sqrt(f, num, args, result); return BR_DONE;
          case OP_FPA_ROUND_TO_INTEGRAL: m_conv.mk_round_to_integral(f, num, args, result); return BR_DONE;
          case OP_FPA_EQ: m_conv.mk_float_eq(f, num, args, result); return BR_DONE;
          case OP_FPA_LT: m_conv.mk_float_lt(f, num, args, result); return BR_DONE;
          case OP_FPA_GT: m_conv.mk_float_gt(f, num, args, result); return BR_DONE;
          case OP_FPA_LE: m_conv.mk_float_le(f, num, args, result); return BR_DONE;
          case OP_FPA_GE: m_conv.mk_float_ge(f, num, args, result); return BR_DONE;
          case OP_FPA_IS_ZERO: m_conv.mk_is_zero(f, num, args, result); return BR_DONE;
          case OP_FPA_IS_NAN: m_conv.mk_is_nan(f, num, args, result); return BR_DONE;
          case OP_FPA_IS_INF: m_conv.mk_is_inf(f, num, args, result); return BR_DONE;
          case OP_FPA_IS_NORMAL: m_conv.mk_is_normal(f, num, args, result); return BR_DONE;
          case OP_FPA_IS_SUBNORMAL: m_conv.mk_is_subnormal(f, num, args, result); return BR_DONE;
          case OP_FPA_IS_POSITIVE: m_conv.mk_is_positive(f, num, args, result); return BR_DONE;
          case OP_FPA_IS_NEGATIVE: m_conv.mk_is_negative(f, num, args, result); return BR_DONE;
          case OP_FPA_TO_FP: m_conv.mk_to_fp(f, num, args, result); return BR_DONE;
          case OP_FPA_TO_FP_UNSIGNED: m_conv.mk_to_fp_unsigned(f, num, args, result); return BR_DONE;
          case OP_FPA_FP: m_conv.mk_fp(f, num, args, result); return BR_DONE;
          case OP_FPA_TO_UBV: m_conv.mk_to_ubv(f, num, args, result); return BR_DONE;
          case OP_FPA_TO_SBV: m_conv.mk_to_sbv(f, num, args, result); return BR_DONE;
          case OP_FPA_TO_REAL: m_conv.mk_to_real(f, num, args, result); return BR_DONE;
          case OP_FPA_TO_IEEE_BV: m_conv.mk_to_ieee_bv(f, num, args, result); return BR_DONE;
  
          case OP_FPA_BVWRAP:
          case OP_FPA_BV2RM:
                  return BR_FAILED;
  
          default:
              TRACE("fpa2bv", tout << "unsupported operator: " << f->get_name() << "\n";
                    for (unsigned i = 0; i < num; i++) tout << mk_ismt2_pp(args[i], m()) << std::endl;);
              NOT_IMPLEMENTED_YET();
          }
      }
      else
      {
          SASSERT(!m_conv.is_float_family(f));
          if (m_conv.fu().contains_floats(f)) {
              m_conv.mk_uf(f, num, args, result);
              return BR_DONE;
          }
      }
  
      return BR_FAILED;
  }
  
  bool fpa2bv_rewriter_cfg::pre_visit(expr * t)
  {
      TRACE("fpa2bv", tout << "pre_visit: " << mk_ismt2_pp(t, m()) << std::endl;);
  
      if (is_quantifier(t)) {
          quantifier * q = to_quantifier(t);
          TRACE("fpa2bv", tout << "pre_visit quantifier [" << q->get_id() << "]: " << mk_ismt2_pp(q->get_expr(), m()) << std::endl;);
          sort_ref_vector new_bindings(m_manager);
          for (unsigned i = 0 ; i < q->get_num_decls(); i++)
                  new_bindings.push_back(q->get_decl_sort(i));
          SASSERT(new_bindings.size() == q->get_num_decls());
          m_bindings.append(new_bindings);
      }
      return true;
  }
  
  
  bool fpa2bv_rewriter_cfg::reduce_quantifier(quantifier * old_q,
                             expr * new_body,
                             expr * const * new_patterns,
                             expr * const * new_no_patterns,
                             expr_ref & result,
                             proof_ref & result_pr) {
      unsigned curr_sz   = m_bindings.size();
      SASSERT(old_q->get_num_decls() <= curr_sz);
      unsigned num_decls = old_q->get_num_decls();
      unsigned old_sz    = curr_sz - num_decls;
      string_buffer<> name_buffer;
      ptr_buffer<sort> new_decl_sorts;
      sbuffer<symbol>  new_decl_names;
      for (unsigned i = 0; i < num_decls; i++) {
          symbol const & n = old_q->get_decl_name(i);
          sort * s         = old_q->get_decl_sort(i);
          if (m_conv.is_float(s)) {
              unsigned ebits = m_conv.fu().get_ebits(s);
              unsigned sbits = m_conv.fu().get_sbits(s);
              name_buffer.reset();
              name_buffer << n << ".bv";
              new_decl_names.push_back(symbol(name_buffer.c_str()));
              new_decl_sorts.push_back(m_conv.bu().mk_sort(sbits+ebits));
          }
          else {
              new_decl_sorts.push_back(s);
              new_decl_names.push_back(n);
          }
      }
      result = m().mk_quantifier(old_q->is_forall(), new_decl_sorts.size(), new_decl_sorts.c_ptr(), new_decl_names.c_ptr(),
                                 new_body, old_q->get_weight(), old_q->get_qid(), old_q->get_skid(),
                                 old_q->get_num_patterns(), new_patterns, old_q->get_num_no_patterns(), new_no_patterns);
      result_pr = nullptr;
      m_bindings.shrink(old_sz);
      TRACE("fpa2bv", tout << "reduce_quantifier[" << old_q->get_depth() << "]: " <<
            mk_ismt2_pp(old_q->get_expr(), m()) << std::endl <<
            " new body: " << mk_ismt2_pp(new_body, m()) << std::endl;
            tout << "result = " << mk_ismt2_pp(result, m()) << std::endl;);
      return true;
  }
  
  bool fpa2bv_rewriter_cfg::reduce_var(var * t, expr_ref & result, proof_ref & result_pr) {
      if (t->get_idx() >= m_bindings.size())
          return false;
      // unsigned inx = m_bindings.size() - t->get_idx() - 1;
  
      expr_ref new_exp(m());
      sort * s = t->get_sort();
      if (m_conv.is_float(s)) {
          expr_ref new_var(m());
          unsigned ebits = m_conv.fu().get_ebits(s);
          unsigned sbits = m_conv.fu().get_sbits(s);
          new_var = m().mk_var(t->get_idx(), m_conv.bu().mk_sort(sbits+ebits));
          new_exp = m_conv.fu().mk_fp(m_conv.bu().mk_extract(sbits+ebits-1, sbits+ebits-1, new_var),
                                      m_conv.bu().mk_extract(ebits - 1, 0, new_var),
                                      m_conv.bu().mk_extract(sbits+ebits-2, ebits, new_var));
      }
      else
          new_exp = m().mk_var(t->get_idx(), s);
  
      result = new_exp;
      result_pr = nullptr;
      TRACE("fpa2bv", tout << "reduce_var: " << mk_ismt2_pp(t, m()) << " -> " << mk_ismt2_pp(result, m()) << std::endl;);
      return true;
  }
  
  template class rewriter_tpl<fpa2bv_rewriter_cfg>;
  