cppcheck: mitigate performance warnings

* include/abg-diff-utils.h (print_snake): pass argument of type
	snake by const reference.
	* include/abg-ir.h (location::operator{==,<}): Likewise.
	* include/abg-viz-dot.h (node_base::{node_base,parent_node,child_node}):
	Likewise.
	* include/abg-viz-svg.h (svg::svg) Likewise.
	* src/abg-config.cc (config::config): Member initialization in ctor body.
	* src/abg-dwarf-reader.cc (class_decl_sptr::add_or_update_class_type):
	Initial value never used.
	* src/abg-ir.cc: (decl_base::priv::priv) Member initialization in ctor body,
	pass argument of type location by const reference.
	(equals): Variable initial value never used.
	* src/abg-reader.cc (read_corpus_from_input): Initial variable
	value never used.
	(build_elf_symbol_db): Use pre-increment.
	* src/abg-suppression-priv.h
	(suppression_matches_type_location): Pass argument of type
	location by const reference.
	* src/abg-suppression.cc: Likewise.

Signed-off-by: Ondrej Oprala <ondrej.oprala@gmail.com>

include/abg-diff-utils.h

@@ -1255,7 +1255,7 @@ template<typename RandomAccessOutputIterator>
 void
 print_snake(RandomAccessOutputIterator a_begin,
 	    RandomAccessOutputIterator b_begin,
-	    const snake s, ostream& out)
+	    const snake &s, ostream& out)
 {
   if (s.is_empty())
     return;

include/abg-ir.h

@@ -245,7 +245,7 @@ public:
   ///
   /// @return true iff both locations are equal.
   bool
-  operator==(const location other) const
+  operator==(const location &other) const
   {return value_ == other.value_;}
 
   /// "Less than" operator of the @ref location type.
@@ -255,7 +255,7 @@ public:
   /// @return true iff the current instance is less than the @p other
   /// one.
   bool
-  operator<(const location other) const
+  operator<(const location &other) const
   {return value_ < other.value_;}
 
   /// Expand the current location into a tripplet file path, line and

include/abg-viz-dot.h

@@ -43,7 +43,7 @@ struct node_base
   const style&		_M_style;
 
   explicit
-  node_base(std::string __id, type __t, const style& __sty)
+  node_base(const std::string& __id, type __t, const style& __sty)
     : _M_id(__id), _M_count(++_M_count_total), 
     _M_type(__t), _M_x_space(0.4), _M_y_space(0.2), _M_style(__sty)
   { }
@@ -66,7 +66,7 @@ extern const style child_sty;
  */
 struct parent_node : public node_base 
 {
-   parent_node(std::string __id) 
+   parent_node(const std::string& __id)
    : node_base(__id, node_base::parent, parent_sty)
    { }
 };
@@ -83,7 +83,7 @@ struct parent_node : public node_base
  */
 struct child_node : public node_base 
 {
-   child_node(std::string __id) 
+   child_node(const std::string& __id)
    : node_base(__id, node_base::child, child_sty)
    { }
 };
@@ -118,7 +118,7 @@ private:
   
 public:
 
-  dot(const std::string __title, 
+  dot(const std::string &__title,
       const canvas& __cv = ansi_letter_canvas,
       const typography& __typo = arial_typo) 
   : _M_title(__title), _M_canvas(__cv), _M_typo(__typo)

include/abg-viz-svg.h

@@ -99,7 +99,7 @@ private:
 
 public:
 
-  svg(const std::string __title, 
+  svg(const std::string &__title,
       const canvas& __cv = ansi_letter_canvas,
       const typography& __typo = arial_typo) 
   : _M_title(__title), _M_canvas(__cv), _M_typo(__typo), _M_y_size(0)

src/abg-config.cc

@@ -35,10 +35,10 @@ namespace abigail
 config::config()
   : m_format_minor("0"),
     m_format_major("1"),
-    m_xml_element_indent(2)
+    m_xml_element_indent(2),
+    m_tu_instr_suffix(".bi"),
+    m_tu_instr_archive_suffix(".abi")
 {
-  m_tu_instr_suffix = ".bi" ;
-  m_tu_instr_archive_suffix = ".abi";
 }
 
 const std::string&

src/abg-dwarf-reader.cc

@@ -11027,8 +11027,7 @@ add_or_update_class_type(read_context&	 ctxt,
 		continue;
 
 	      int64_t offset_in_bits = 0;
-	      bool is_laid_out = false;
-	      is_laid_out = die_member_offset(&child, offset_in_bits);
+	      bool is_laid_out = die_member_offset(&child, offset_in_bits);
 	      // For now, is_static == !is_laid_out.  When we have
 	      // templates, we'll try to be more specific.  For now,
 	      // this approximation should do OK.

src/abg-ir.cc

@@ -2599,14 +2599,14 @@ struct decl_base::priv
       location_(locus),
       context_(),
       name_(name),
+      qualified_name_(name),
       linkage_name_(linkage_name),
       visibility_(vis)
   {
-    qualified_name_ = name;
     is_anonymous_ = name_.empty();
   }
 
-  priv(location l)
+  priv(const location& l)
     : in_pub_sym_tab_(false),
       is_anonymous_(true),
       location_(l),
@@ -9959,9 +9959,7 @@ scope_type_decl::scope_type_decl(const environment*	env,
 bool
 equals(const scope_type_decl& l, const scope_type_decl& r, change_kind* k)
 {
-  bool result = true;
-
-  result = equals(static_cast<const scope_decl&>(l),
+  bool result = equals(static_cast<const scope_decl&>(l),
 		  static_cast<const scope_decl&>(r),
 		  k);
 

src/abg-reader.cc

@@ -1768,10 +1768,9 @@ read_corpus_from_input(read_context& ctxt)
     corp.set_needed(needed);
 
   string_elf_symbols_map_sptr fn_sym_db, var_sym_db;
-  bool is_ok = false;
 
   // Read the symbol databases.
-  is_ok = read_symbol_db_from_input(ctxt, fn_sym_db, var_sym_db);
+  bool is_ok = read_symbol_db_from_input(ctxt, fn_sym_db, var_sym_db);
   if (is_ok)
     {
       assert(fn_sym_db || var_sym_db);
@@ -2556,7 +2555,7 @@ build_elf_symbol_db(read_context& ctxt,
       while (std::getline(aliases, item, ','))
         elems.push_back(item);
       for (std::vector<string>::iterator alias = elems.begin();
-           alias != elems.end(); alias++)
+           alias != elems.end(); ++alias)
         {
           string_elf_symbol_sptr_map_type::const_iterator i =
           id_sym_map.find(*alias);

src/abg-suppression-priv.h

@@ -774,7 +774,7 @@ suppression_matches_type_name(const suppr::type_suppression&	s,
 
 bool
 suppression_matches_type_location(const type_suppression&	s,
-				  const location		loc);
+				  const location&		loc);
 
 bool
 suppression_matches_type_location(const type_suppression&	s,

src/abg-suppression.cc

@@ -912,7 +912,7 @@ suppression_matches_type_name(const suppr::type_suppression&	s,
 /// @return true iff the suppression @p s matches location @p loc.
 bool
 suppression_matches_type_location(const type_suppression&	s,
-				  const location		loc)
+				  const location&		loc)
 {
   if (loc)
     {