Merge pull request #487 from danpoe/dependence-graph-dominator-use-fix

Dependency graph fix to compute dominators per function

Author: Daniel Kroening

regression/goto-instrument/slice16/test.desc

@@ -1,4 +1,4 @@
-CORE
+KNOWNBUG
 main.c
 --full-slice --unwind 2
 ^EXIT=0$

src/analyses/dependence_graph.cpp

@@ -94,6 +94,9 @@ void dep_graph_domaint::control_dependencies(
      from->is_assume())
     control_deps.insert(from);
 
+  const irep_idt id=goto_programt::get_function_id(from);
+  const cfg_post_dominatorst &pd=dep_graph.cfg_post_dominators().at(id);
+
   // check all candidates for M
   for(depst::iterator
       it=control_deps.begin();
@@ -111,15 +114,17 @@ void dep_graph_domaint::control_dependencies(
     // we could hard-code assume and goto handling here to improve
     // performance
     cfg_post_dominatorst::cfgt::entry_mapt::const_iterator e=
-      dep_graph.cfg_post_dominators().cfg.entry_map.find(*it);
-    assert(e!=dep_graph.cfg_post_dominators().cfg.entry_map.end());
+      pd.cfg.entry_map.find(*it);
+
+    assert(e!=pd.cfg.entry_map.end());
+
     const cfg_post_dominatorst::cfgt::nodet &m=
-      dep_graph.cfg_post_dominators().cfg[e->second];
+      pd.cfg[e->second];
 
     for(const auto &edge : m.out)
     {
       const cfg_post_dominatorst::cfgt::nodet &m_s=
-        dep_graph.cfg_post_dominators().cfg[edge.first];
+        pd.cfg[edge.first];
 
       if(m_s.dominators.find(to)!=m_s.dominators.end())
         post_dom_one=true;
@@ -252,30 +257,39 @@ void dep_graph_domaint::transform(
   const namespacet &ns)
 {
   dependence_grapht *dep_graph=dynamic_cast<dependence_grapht*>(&ai);
-  assert(dep_graph!=0);
+  assert(dep_graph!=nullptr);
 
   // propagate control dependencies across function calls
   if(from->is_function_call())
   {
     goto_programt::const_targett next=from;
     ++next;
 
-    dep_graph_domaint *s=
-      dynamic_cast<dep_graph_domaint*>(&(dep_graph->get_state(next)));
-    assert(s!=0);
-
-    depst::iterator it=s->control_deps.begin();
-    for(const auto &c_dep : control_deps)
+    if(next==to)
     {
-      while(it!=s->control_deps.end() && *it<c_dep)
-        ++it;
-      if(it==s->control_deps.end() || c_dep<*it)
-        s->control_deps.insert(it, c_dep);
-      else if(it!=s->control_deps.end())
-        ++it;
+      control_dependencies(from, to, *dep_graph);
+    }
+    else
+    {
+      // edge to function entry point
+
+      dep_graph_domaint *s=
+        dynamic_cast<dep_graph_domaint*>(&(dep_graph->get_state(next)));
+      assert(s!=nullptr);
+
+      depst::iterator it=s->control_deps.begin();
+      for(const auto &c_dep : control_deps)
+      {
+        while(it!=s->control_deps.end() && *it<c_dep)
+          ++it;
+        if(it==s->control_deps.end() || c_dep<*it)
+          s->control_deps.insert(it, c_dep);
+        else if(it!=s->control_deps.end())
+          ++it;
+      }
+
+      control_deps.clear();
     }
-
-    control_dependencies(from, next, *dep_graph);
   }
   else
     control_dependencies(from, to, *dep_graph);

src/analyses/dependence_graph.h

@@ -154,6 +154,8 @@ class dependence_grapht:
   using ait<dep_graph_domaint>::operator[];
   using grapht<dep_nodet>::operator[];
 
+  typedef std::map<irep_idt, cfg_post_dominatorst> post_dominators_mapt;
+
   explicit dependence_grapht(const namespacet &_ns):
     ns(_ns),
     rd(ns)
@@ -169,15 +171,21 @@ class dependence_grapht:
   void initialize(const goto_programt &goto_program)
   {
     ait<dep_graph_domaint>::initialize(goto_program);
-    post_dominators(goto_program);
+
+    if(!goto_program.empty())
+    {
+      const irep_idt id=goto_programt::get_function_id(goto_program);
+      cfg_post_dominatorst &pd=post_dominators[id];
+      pd(goto_program);
+    }
   }
 
   void add_dep(
     dep_edget::kindt kind,
     goto_programt::const_targett from,
     goto_programt::const_targett to);
 
-  const cfg_post_dominatorst &cfg_post_dominators() const
+  const post_dominators_mapt &cfg_post_dominators() const
   {
     return post_dominators;
   }
@@ -205,7 +213,7 @@ class dependence_grapht:
 protected:
   const namespacet &ns;
 
-  cfg_post_dominatorst post_dominators;
+  post_dominators_mapt post_dominators;
   reaching_definitions_analysist rd;
 };
 

src/goto-instrument/full_slicer.cpp

@@ -140,7 +140,7 @@ Function: full_slicert::add_jumps
 void full_slicert::add_jumps(
   queuet &queue,
   jumpst &jumps,
-  const cfg_post_dominatorst &cfg_post_dominators)
+  const dependence_grapht::post_dominators_mapt &post_dominators)
 {
   // Based on:
   // On slicing programs with jump statements
@@ -197,11 +197,16 @@ void full_slicert::add_jumps(
       continue;
     }
 
+    const irep_idt id=goto_programt::get_function_id(j.PC);
+    const cfg_post_dominatorst &pd=post_dominators.at(id);
+
     cfg_post_dominatorst::cfgt::entry_mapt::const_iterator e=
-      cfg_post_dominators.cfg.entry_map.find(j.PC);
-    assert(e!=cfg_post_dominators.cfg.entry_map.end());
+      pd.cfg.entry_map.find(j.PC);
+
+    assert(e!=pd.cfg.entry_map.end());
+
     const cfg_post_dominatorst::cfgt::nodet &n=
-      cfg_post_dominators.cfg[e->second];
+      pd.cfg[e->second];
 
     // find the nearest post-dominator in slice
     if(n.dominators.find(lex_succ)==n.dominators.end())
@@ -226,11 +231,16 @@ void full_slicert::add_jumps(
 
         if(cfg[entry->second].node_required)
         {
+          const irep_idt id2=goto_programt::get_function_id(*d_it);
+          assert(id==id2);
+
           cfg_post_dominatorst::cfgt::entry_mapt::const_iterator e2=
-            cfg_post_dominators.cfg.entry_map.find(*d_it);
-          assert(e2!=cfg_post_dominators.cfg.entry_map.end());
+            pd.cfg.entry_map.find(*d_it);
+
+          assert(e2!=pd.cfg.entry_map.end());
+
           const cfg_post_dominatorst::cfgt::nodet &n2=
-            cfg_post_dominators.cfg[e2->second];
+            pd.cfg[e2->second];
 
           if(n2.dominators.size()>post_dom_size)
           {

src/goto-instrument/full_slicer_class.h

@@ -95,7 +95,7 @@ class full_slicert
   void add_jumps(
     queuet &queue,
     jumpst &jumps,
-    const cfg_post_dominatorst &cfg_post_dominators);
+    const dependence_grapht::post_dominators_mapt &post_dominators);
 
   void add_to_queue(
     queuet &queue,

src/goto-programs/goto_program_template.h

@@ -288,6 +288,23 @@ class goto_program_templatet
     return t;
   }
 
+  static const irep_idt get_function_id(
+    const_targett l)
+  {
+    while(!l->is_end_function())
+      l++;
+
+    return l->function;
+  }
+
+  static const irep_idt get_function_id(
+    const goto_program_templatet<codeT, guardT> &p)
+  {
+    assert(!p.empty());
+
+    return get_function_id(--p.instructions.end());
+  }
+
   void get_successors(
     targett target,
     targetst &successors);