introduce instructiont::dead_symbol()

This mirrors the change in #5861 by replacing the use of code_deadt by
directly returning the symbol_exprt.  The client code is simplified.

Author: kroening

src/analyses/constant_propagator.cpp

@@ -191,8 +191,7 @@ void constant_propagator_domaint::transform(
   }
   else if(from->is_dead())
   {
-    const auto &code_dead = from->get_dead();
-    values.set_to_top(code_dead.symbol());
+    values.set_to_top(from->dead_symbol());
   }
   else if(from->is_function_call())
   {

src/analyses/custom_bitvector_analysis.cpp

@@ -304,14 +304,11 @@ void custom_bitvector_domaint::transform(
     break;
 
   case DEAD:
-    {
-      const code_deadt &code_dead=to_code_dead(instruction.code);
-      assign_lhs(code_dead.symbol(), vectorst());
+    assign_lhs(instruction.dead_symbol(), vectorst());
 
-      // is it a pointer?
-      if(code_dead.symbol().type().id()==ID_pointer)
-        assign_lhs(dereference_exprt(code_dead.symbol()), vectorst());
-    }
+    // is it a pointer?
+    if(instruction.dead_symbol().type().id() == ID_pointer)
+      assign_lhs(dereference_exprt(instruction.dead_symbol()), vectorst());
     break;
 
   case FUNCTION_CALL:

src/analyses/escape_analysis.cpp

@@ -210,11 +210,8 @@ void escape_domaint::transform(
     break;
 
   case DEAD:
-    {
-      const code_deadt &code_dead=to_code_dead(instruction.code);
-      aliases.isolate(code_dead.get_identifier());
-      assign_lhs_cleanup(code_dead.symbol(), std::set<irep_idt>());
-    }
+    aliases.isolate(instruction.dead_symbol().get_identifier());
+    assign_lhs_cleanup(instruction.dead_symbol(), std::set<irep_idt>());
     break;
 
   case FUNCTION_CALL:
@@ -487,14 +484,14 @@ void escape_analysist::instrument(
       }
       else if(instruction.type == DEAD)
       {
-        const code_deadt &code_dead = to_code_dead(instruction.code);
+        const auto &dead_symbol = instruction.dead_symbol();
 
         std::set<irep_idt> cleanup_functions1;
 
         const escape_domaint &d = operator[](i_it);
 
         const escape_domaint::cleanup_mapt::const_iterator m_it =
-          d.cleanup_map.find("&" + id2string(code_dead.get_identifier()));
+          d.cleanup_map.find("&" + id2string(dead_symbol.get_identifier()));
 
         // does it have a cleanup function for the object?
         if(m_it != d.cleanup_map.end())
@@ -506,22 +503,12 @@ void escape_analysist::instrument(
 
         std::set<irep_idt> cleanup_functions2;
 
-        d.check_lhs(code_dead.symbol(), cleanup_functions2);
+        d.check_lhs(dead_symbol, cleanup_functions2);
 
         insert_cleanup(
-          gf_entry.second,
-          i_it,
-          code_dead.symbol(),
-          cleanup_functions1,
-          true,
-          ns);
+          gf_entry.second, i_it, dead_symbol, cleanup_functions1, true, ns);
         insert_cleanup(
-          gf_entry.second,
-          i_it,
-          code_dead.symbol(),
-          cleanup_functions2,
-          false,
-          ns);
+          gf_entry.second, i_it, dead_symbol, cleanup_functions2, false, ns);
 
         for(const auto &c : cleanup_functions1)
         {

src/analyses/global_may_alias.cpp

@@ -127,11 +127,8 @@ void global_may_alias_domaint::transform(
   }
 
   case DEAD:
-  {
-    const code_deadt &code_dead = to_code_dead(instruction.code);
-    aliases.isolate(code_dead.get_identifier());
+    aliases.isolate(instruction.dead_symbol().get_identifier());
     break;
-  }
 
   case FUNCTION_CALL: // Probably safe
   case GOTO:          // Ignoring the guard is a valid over-approximation

src/analyses/goto_rw.cpp

@@ -815,10 +815,7 @@ void goto_rw(
 
   case DEAD:
     rw_set.get_objects_rec(
-      function,
-      target,
-      rw_range_sett::get_modet::LHS_W,
-      to_code_dead(target->code).symbol());
+      function, target, rw_range_sett::get_modet::LHS_W, target->dead_symbol());
     break;
 
   case DECL:

src/analyses/interval_domain.cpp

@@ -75,7 +75,7 @@ void interval_domaint::transform(
     break;
 
   case DEAD:
-    havoc_rec(to_code_dead(instruction.code).symbol());
+    havoc_rec(instruction.dead_symbol());
     break;
 
   case ASSIGN:

src/analyses/local_bitvector_analysis.cpp

@@ -293,15 +293,12 @@ void local_bitvector_analysist::build()
     }
 
     case DEAD:
-    {
-      const code_deadt &code_dead = to_code_dead(instruction.code);
       assign_lhs(
-        code_dead.symbol(),
+        instruction.dead_symbol(),
         exprt(ID_uninitialized),
         loc_info_src,
         loc_info_dest);
       break;
-    }
 
     case FUNCTION_CALL:
     {

src/analyses/local_may_alias.cpp

@@ -390,11 +390,9 @@ void local_may_aliast::build(const goto_functiont &goto_function)
     }
 
     case DEAD:
-    {
-      const code_deadt &code_dead = to_code_dead(instruction.code);
-      assign_lhs(code_dead.symbol(), nil_exprt(), loc_info_src, loc_info_dest);
+      assign_lhs(
+        instruction.dead_symbol(), nil_exprt(), loc_info_src, loc_info_dest);
       break;
-    }
 
     case FUNCTION_CALL:
     {

src/analyses/reaching_definitions.cpp

@@ -169,7 +169,7 @@ void rd_range_domaint::transform_dead(
   const namespacet &,
   locationt from)
 {
-  const irep_idt &identifier = to_code_dead(from->code).get_identifier();
+  const irep_idt &identifier = from->dead_symbol().get_identifier();
 
   valuest::iterator entry=values.find(identifier);
 

src/analyses/variable-sensitivity/variable_sensitivity_domain.cpp

@@ -55,16 +55,10 @@ void variable_sensitivity_domaint::transform(
   break;
 
   case DEAD:
-  {
     // Remove symbol from map, the only time this occurs now (keep TOP.)
     // It should be the case that DEAD only provides symbols for deletion.
-    const exprt &expr = to_code_dead(instruction.code).symbol();
-    if(expr.id() == ID_symbol)
-    {
-      abstract_state.erase(to_symbol_expr(expr));
-    }
-  }
-  break;
+    abstract_state.erase(instruction.dead_symbol());
+    break;
 
   case ASSIGN:
   {

src/goto-diff/change_impact.cpp

@@ -84,7 +84,7 @@ void full_slicert::operator()(
     }
     else if(instruction->is_dead())
     {
-      const auto &s=to_code_dead(instruction->code).symbol();
+      const auto &s=instruction->dead_symbol();
       decl_dead[s.get_identifier()].push(instruction_node_index);
     }
   }

src/goto-instrument/full_slicer.cpp

@@ -290,7 +290,7 @@ void full_slicert::operator()(
     }
     else if(instruction->is_dead())
     {
-      const auto &s = to_code_dead(instruction->code).symbol();
+      const auto &s = instruction->dead_symbol();
       decl_dead[s.get_identifier()].push(instruction_node_index);
     }
   }

src/goto-instrument/goto_program2code.cpp

@@ -94,7 +94,7 @@ void goto_program2codet::build_dead_map()
   {
     if(instruction.is_dead())
     {
-      dead_map[instruction.get_dead().get_identifier()] =
+      dead_map[instruction.dead_symbol().get_identifier()] =
         instruction.location_number;
     }
   }

src/goto-programs/goto_program.cpp

@@ -884,9 +884,9 @@ void goto_programt::instructiont::validate(
       source_location);
     DATA_CHECK_WITH_DIAGNOSTICS(
       vm,
-      !ns.lookup(get_dead().get_identifier(), table_symbol),
+      !ns.lookup(dead_symbol().get_identifier(), table_symbol),
       "removed symbols should be known",
-      id2string(get_dead().get_identifier()),
+      id2string(dead_symbol().get_identifier()),
       source_location);
     break;
   case FUNCTION_CALL:
@@ -966,13 +966,9 @@ void goto_programt::instructiont::transform(
 
   case DEAD:
   {
-    auto new_symbol = f(get_dead().symbol());
+    auto new_symbol = f(dead_symbol());
     if(new_symbol.has_value())
-    {
-      auto new_dead = get_dead();
-      new_dead.symbol() = to_symbol_expr(*new_symbol);
-      set_dead(new_dead);
-    }
+      dead_symbol() = to_symbol_expr(*new_symbol);
   }
   break;
 
@@ -1050,7 +1046,7 @@ void goto_programt::instructiont::apply(
     break;
 
   case DEAD:
-    f(get_dead().symbol());
+    f(dead_symbol());
     break;
 
   case FUNCTION_CALL:

src/goto-programs/goto_program.h

@@ -18,6 +18,7 @@ Author: Daniel Kroening, [email protected]
 #include <sstream>
 #include <string>
 
+#include <util/deprecate.h>
 #include <util/invariant.h>
 #include <util/namespace.h>
 #include <util/source_location.h>
@@ -218,13 +219,29 @@ class goto_programt
     }
 
     /// Get the dead statement for DEAD
+    DEPRECATED(SINCE(2021, 2, 24, "Use dead_symbol instead"))
     const code_deadt &get_dead() const
     {
       PRECONDITION(is_dead());
       return to_code_dead(code);
     }
 
+    /// Get the symbol for DEAD
+    const symbol_exprt &dead_symbol() const
+    {
+      PRECONDITION(is_dead());
+      return to_code_dead(code).symbol();
+    }
+
+    /// Get the symbol for DEAD
+    symbol_exprt &dead_symbol()
+    {
+      PRECONDITION(is_dead());
+      return to_code_dead(code).symbol();
+    }
+
     /// Set the dead statement for DEAD
+    DEPRECATED(SINCE(2021, 2, 24, "Use dead_symbol instead"))
     void set_dead(code_deadt c)
     {
       PRECONDITION(is_dead());

src/goto-symex/symex_dead.cpp

@@ -19,9 +19,7 @@ Author: Daniel Kroening, [email protected]
 void goto_symext::symex_dead(statet &state)
 {
   const goto_programt::instructiont &instruction=*state.source.pc;
-
-  const code_deadt &code = instruction.get_dead();
-  symex_dead(state, code.symbol());
+  symex_dead(state, instruction.dead_symbol());
 }
 
 void goto_symext::symex_dead(statet &state, const symbol_exprt &symbol_expr)