During comparison use symbol name + version as decl ID

* include/abg-ir.h ({var,function}_decl::get_id): New member
	function declarations.
	* src/abg-ir.cc ({var,function}_decl::get_id): New member function
	definitions.
	* src/abg-comparison.cc
	(corpus_diff::priv::ensure_lookup_tables_populated): Use the
	::get_id() function to get an identifier for the function or
	variable.
	* src/abg-corpus.cc (symtab_build_visitor_type::build_id): Use the
	get_id of the function/variable.

Signed-off-by: Dodji Seketeli <dodji@redhat.com>

include/abg-ir.h

@@ -1493,6 +1493,9 @@ public:
   var_decl_sptr
   clone() const;
 
+  string
+  get_id() const;
+
   virtual size_t
   get_hash() const;
 
@@ -1770,6 +1773,9 @@ public:
   virtual size_t
   get_hash() const;
 
+  string
+  get_id() const;
+
   virtual bool
   traverse(ir_node_visitor&);
 

src/abg-comparison.cc

@@ -6200,9 +6200,7 @@ corpus_diff::priv::ensure_lookup_tables_populated()
 	assert(i < first_->get_functions().size());
 
 	function_decl* deleted_fn = first_->get_functions()[i];
-	string n = deleted_fn->get_linkage_name();
-	if (n.empty())
-	  n = deleted_fn->get_pretty_representation();
+	string n = deleted_fn->get_id();
 	assert(!n.empty());
 	assert(deleted_fns_.find(n) == deleted_fns_.end());
 	deleted_fns_[n] = deleted_fn;
@@ -6219,25 +6217,11 @@ corpus_diff::priv::ensure_lookup_tables_populated()
 	  {
 	    unsigned i = *iit;
 	    function_decl* added_fn = second_->get_functions()[i];
-	    string n = added_fn->get_linkage_name();
-	    if (n.empty())
-	      n = added_fn->get_pretty_representation();
+	    string n = added_fn->get_id();
 	    assert(!n.empty());
 	    assert(added_fns_.find(n) == added_fns_.end());
 	    string_function_ptr_map::const_iterator j =
 	      deleted_fns_.find(n);
-	    if (j == deleted_fns_.end())
-	      {
-		// It can happen that an old dwarf producer might not
-		// have emitted the mangled name of the first diff
-		// subject.  Int hat case, we need to try to use the
-		// function synthetic signature here.
-		// TODO: also query the underlying elf file's .dynsym
-		// symbol table to see if the symbol is present in the
-		// first diff subject before for real.
-		if (!added_fn->get_linkage_name().empty())
-		  j = deleted_fns_.find(added_fn->get_pretty_representation());
-	      }
 	    if (j != deleted_fns_.end())
 	      {
 		if (*j->second != *added_fn)
@@ -6294,9 +6278,7 @@ corpus_diff::priv::ensure_lookup_tables_populated()
 	assert(i < first_->get_variables().size());
 
 	var_decl* deleted_var = first_->get_variables()[i];
-	string n = deleted_var->get_linkage_name();
-	if (n.empty())
-	  n = deleted_var->get_pretty_representation();
+	string n = deleted_var->get_id();
 	assert(!n.empty());
 	assert(deleted_vars_.find(n) == deleted_vars_.end());
 	deleted_vars_[n] = deleted_var;
@@ -6313,9 +6295,7 @@ corpus_diff::priv::ensure_lookup_tables_populated()
 	  {
 	    unsigned i = *iit;
 	    var_decl* added_var = second_->get_variables()[i];
-	    string n = added_var->get_linkage_name();
-	    if (n.empty())
-	      n = added_var->get_name();
+	    string n = added_var->get_id();
 	    assert(!n.empty());
 	    {
 	      string_var_ptr_map::const_iterator k = added_vars_.find(n);

src/abg-corpus.cc

@@ -201,13 +201,7 @@ public:
   /// @return the unique ID.
   string
   build_id(const function_decl& fn)
-  {
-    if (elf_symbol_sptr s = fn.get_symbol())
-      return s->get_id_string();
-    else if (!fn.get_linkage_name().empty())
-      return fn.get_linkage_name();
-    return fn.get_pretty_representation();
-  }
+  {return fn.get_id();}
 
   /// Build a string that uniquely identifies a var_decl inside
   /// one corpus.
@@ -222,13 +216,7 @@ public:
   /// @return the unique ID.
   string
   build_id(const var_decl& var)
-  {
-    if (elf_symbol_sptr s = var.get_symbol())
-      return s->get_id_string();
-    else if (!var.get_linkage_name().empty())
-      return var.get_linkage_name();
-    return var.get_pretty_representation();
-  }
+  {return var.get_id();}
 
   /// Build a string that uniquely identifies a function_decl inside
   /// one corpus.

src/abg-ir.cc

@@ -4272,6 +4272,25 @@ var_decl::operator==(const decl_base& o) const
   return *c0 == *c1;
 }
 
+/// Return an ID that tries to uniquely identify the variable inside a
+/// program or a library.
+///
+/// So if the variable has an underlying elf symbol, the ID is the
+/// concatenation of the symbol name and its version.  Otherwise, the
+/// ID is the linkage name if its non-null.  Otherwise, it's the
+/// pretty representation of the variable.
+///
+/// @return the ID.
+string
+var_decl::get_id() const
+{
+  if (elf_symbol_sptr s = get_symbol())
+    return s->get_id_string();
+  else if (!get_linkage_name().empty())
+    return get_linkage_name();
+  return get_pretty_representation();
+}
+
 /// Return the hash value for the current instance.
 ///
 /// @return the hash value.
@@ -5014,6 +5033,25 @@ function_decl::get_hash() const
   return hash_fn(*this);
 }
 
+/// Return an ID that tries to uniquely identify the function inside a
+/// program or a library.
+///
+/// So if the function has an underlying elf symbol, the ID is the
+/// concatenation of the symbol name and its version.  Otherwise, the
+/// ID is the linkage name if its non-null.  Otherwise, it's the
+/// pretty representation of the function.
+///
+/// @return the ID.
+string
+function_decl::get_id() const
+{
+  if (elf_symbol_sptr s = get_symbol())
+    return s->get_id_string();
+  else if (!get_linkage_name().empty())
+    return get_linkage_name();
+  return get_pretty_representation();
+}
+
 /// This implements the ir_traversable_base::traverse pure virtual
 /// function.
 ///