Merge pull request #1268 from diffblue/link-goto-model

factor out goto model linking into separate file

Author: Daniel Kroening

src/goto-programs/Makefile

@@ -26,6 +26,7 @@ SRC = basic_blocks.cpp \
       interpreter.cpp \
       interpreter_evaluate.cpp \
       json_goto_trace.cpp \
+      link_goto_model.cpp \
       link_to_library.cpp \
       loop_ids.cpp \
       mm_io.cpp \

src/goto-programs/link_goto_model.cpp

@@ -0,0 +1,182 @@
+/*******************************************************************\
+
+Module: Link Goto Programs
+
+Author: Michael Tautschnig, Daniel Kroening
+
+\*******************************************************************/
+
+/// \file
+/// Link Goto Programs
+
+#include "link_goto_model.h"
+
+#include <unordered_set>
+
+#include <util/base_type.h>
+#include <util/symbol.h>
+#include <util/rename_symbol.h>
+
+#include <linking/linking_class.h>
+
+#include "goto_model.h"
+
+static void rename_symbols_in_function(
+  goto_functionst::goto_functiont &function,
+  const rename_symbolt &rename_symbol)
+{
+  goto_programt &program=function.body;
+  rename_symbol(function.type);
+
+  Forall_goto_program_instructions(iit, program)
+  {
+    rename_symbol(iit->code);
+    rename_symbol(iit->guard);
+  }
+}
+
+/// Link a set of goto functions, considering weak symbols
+/// and symbol renaming
+static bool link_functions(
+  symbol_tablet &dest_symbol_table,
+  goto_functionst &dest_functions,
+  const symbol_tablet &src_symbol_table,
+  goto_functionst &src_functions,
+  const rename_symbolt &rename_symbol,
+  const std::unordered_set<irep_idt, irep_id_hash> &weak_symbols,
+  const replace_symbolt &object_type_updates)
+{
+  namespacet ns(dest_symbol_table);
+  namespacet src_ns(src_symbol_table);
+
+  // merge functions
+  Forall_goto_functions(src_it, src_functions)
+  {
+    // the function might have been renamed
+    rename_symbolt::expr_mapt::const_iterator e_it=
+      rename_symbol.expr_map.find(src_it->first);
+
+    irep_idt final_id=src_it->first;
+
+    if(e_it!=rename_symbol.expr_map.end())
+      final_id=e_it->second;
+
+    // already there?
+    goto_functionst::function_mapt::iterator dest_f_it=
+      dest_functions.function_map.find(final_id);
+
+    if(dest_f_it==dest_functions.function_map.end()) // not there yet
+    {
+      rename_symbols_in_function(src_it->second, rename_symbol);
+
+      goto_functionst::goto_functiont &in_dest_symbol_table=
+        dest_functions.function_map[final_id];
+
+      in_dest_symbol_table.body.swap(src_it->second.body);
+      in_dest_symbol_table.type=src_it->second.type;
+    }
+    else // collision!
+    {
+      goto_functionst::goto_functiont &in_dest_symbol_table=
+        dest_functions.function_map[final_id];
+
+      goto_functionst::goto_functiont &src_func=src_it->second;
+
+      if(in_dest_symbol_table.body.instructions.empty() ||
+         weak_symbols.find(final_id)!=weak_symbols.end())
+      {
+        // the one with body wins!
+        rename_symbols_in_function(src_func, rename_symbol);
+
+        in_dest_symbol_table.body.swap(src_func.body);
+        in_dest_symbol_table.type=src_func.type;
+      }
+      else if(src_func.body.instructions.empty() ||
+              src_ns.lookup(src_it->first).is_weak)
+      {
+        // just keep the old one in dest
+      }
+      else if(in_dest_symbol_table.type.get_bool(ID_C_inlined))
+      {
+        // ok, we silently ignore
+      }
+      else
+      {
+        // the linking code will have ensured that types match
+        rename_symbol(src_func.type);
+        INVARIANT(base_type_eq(in_dest_symbol_table.type, src_func.type, ns),
+                  "linking ensures that types match");
+      }
+    }
+  }
+
+  // apply macros
+  rename_symbolt macro_application;
+
+  forall_symbols(it, dest_symbol_table.symbols)
+    if(it->second.is_macro && !it->second.is_type)
+    {
+      const symbolt &symbol=it->second;
+
+      INVARIANT(symbol.value.id()==ID_symbol, "must have symbol");
+      const irep_idt &id=to_symbol_expr(symbol.value).get_identifier();
+
+      #if 0
+      if(!base_type_eq(symbol.type, ns.lookup(id).type, ns))
+      {
+        std::cerr << symbol << '\n';
+        std::cerr << ns.lookup(id) << '\n';
+      }
+      INVARIANT(base_type_eq(symbol.type, ns.lookup(id).type, ns),
+                "type matches");
+      #endif
+
+      macro_application.insert_expr(symbol.name, id);
+    }
+
+  if(!macro_application.expr_map.empty())
+    Forall_goto_functions(dest_it, dest_functions)
+      rename_symbols_in_function(dest_it->second, macro_application);
+
+  if(!object_type_updates.expr_map.empty())
+  {
+    Forall_goto_functions(dest_it, dest_functions)
+      Forall_goto_program_instructions(iit, dest_it->second.body)
+      {
+        object_type_updates(iit->code);
+        object_type_updates(iit->guard);
+      }
+  }
+
+  return false;
+}
+
+void link_goto_model(
+  goto_modelt &dest,
+  goto_modelt &src,
+  message_handlert &message_handler)
+{
+  typedef std::unordered_set<irep_idt, irep_id_hash> id_sett;
+  id_sett weak_symbols;
+
+  forall_symbols(it, dest.symbol_table.symbols)
+    if(it->second.is_weak)
+      weak_symbols.insert(it->first);
+
+  linkingt linking(dest.symbol_table,
+                   src.symbol_table,
+                   message_handler);
+
+  if(linking.typecheck_main())
+    throw 0;
+
+  if(link_functions(
+      dest.symbol_table,
+      dest.goto_functions,
+      src.symbol_table,
+      src.goto_functions,
+      linking.rename_symbol,
+      weak_symbols,
+      linking.object_type_updates))
+    throw 0;
+}

src/goto-programs/link_goto_model.h

@@ -0,0 +1,23 @@
+/*******************************************************************\
+
+Module: Read Goto Programs
+
+Author: Daniel Kroening, kroening@kroening.com
+
+\*******************************************************************/
+
+/// \file
+/// Read Goto Programs
+
+#ifndef CPROVER_GOTO_PROGRAMS_LINK_GOTO_MODEL_H
+#define CPROVER_GOTO_PROGRAMS_LINK_GOTO_MODEL_H
+
+class goto_modelt;
+class message_handlert;
+
+void link_goto_model(
+  goto_modelt &dest,
+  goto_modelt &src,
+  message_handlert &);
+
+#endif // CPROVER_GOTO_PROGRAMS_LINK_GOTO_MODEL_H