abg-writer.cc

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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// -*- mode: C++ -*-
//
// Copyright (C) 2013-2025 Red Hat, Inc.

/// @file
///
/// This file contains the definitions of the entry points to
/// de-serialize an instance of @ref abigail::translation_unit to an
/// ABI Instrumentation file in libabigail native XML format.  This
/// native XML format is named "abixml".

#include "config.h"
#include <assert.h>
#include <algorithm>
#include <fstream>
#include <iomanip>
#include <ios>
#include <iostream>
#include <memory>
#include <sstream>
#include <stack>
#include <unordered_map>
#include <vector>

#include "abg-tools-utils.h"
#include "abg-ir-priv.h"

#include "abg-ir-priv.h"
#include "abg-internal.h"
// <headers defining libabigail's API go under here>
ABG_BEGIN_EXPORT_DECLARATIONS

#include "abg-config.h"
#include "abg-corpus.h"
#include "abg-hash.h"
#include "abg-sptr-utils.h"

#include "abg-writer.h"
#include "abg-libxml-utils.h"
#include "abg-fwd.h"

ABG_END_EXPORT_DECLARATIONS
// </headers defining libabigail's API>

namespace abigail
{
using std::cerr;
using std::shared_ptr;
using std::dynamic_pointer_cast;
using std::static_pointer_cast;
using std::ofstream;
using std::ostream;
using std::ostringstream;
using std::list;
using std::vector;
using std::stack;
using std::unordered_map;
using abigail::sptr_utils::noop_deleter;

/// The namespace for the native XML file format writer.
///
/// It contains utilities to serialize ABI artifacts from the @ref ir
/// namespace into the native XML format.
namespace xml_writer
{

class id_manager
{
  const environment& m_env;
  mutable unsigned long long m_cur_id;

  unsigned long long
  get_new_id() const
  { return ++m_cur_id; }

public:
  id_manager(const environment& env)
    : m_env(env),
      m_cur_id(0) {}

  const environment&
  get_environment() const
  {return m_env;}

  /// Return a unique string representing a numerical id.
  interned_string
  get_id() const
  {
    ostringstream o;
    o << get_new_id();
    const environment& env = get_environment();
    return env.intern(o.str());
  }

  /// Return a unique string representing a numerical ID, prefixed by
  /// prefix.
  ///
  /// @param prefix the prefix of the returned unique id.
  interned_string
  get_id_with_prefix(const string& prefix) const
  {
    ostringstream o;
    o << prefix << get_new_id();
    const environment& env = get_environment();
    return env.intern(o.str());
  }
};

/// A convenience typedef for a map that associates a pointer to type
/// to a string.
typedef unordered_map<type_base*, interned_string> type_ptr_map;

/// The hashing functor of for the set of non canonicalized types, aka
/// @ref nc_type_ptr_set_type
struct non_canonicalized_type_hash
{
  /// Hashing function
  ///
  /// This hashes a string representation of the non canonicalized
  /// types.  For now, two typedefs with different names but with the
  /// same underlying types will hash differently.
  ///
  /// TODO: try making typedefs with different names hash the same if
  /// their underlying types are equal and see what breaks.
  ///
  /// @param p the non canonicalized type to hash.
  ///
  /// @return the hash value.
  size_t
  operator() (const type_base* p) const
  {
    ABG_ASSERT(is_non_canonicalized_type(p));
    std::hash<string> h;
    return h(p->get_pretty_representation(/*internal=*/false,
                      // By choosing the
                      // non-internal format,
                      // classes and structs are
                      // named differently and
                      // typedefs and
                      // classes/structs are named
                      // differently.  This
                      // implies less uncertainty
                      // in the sorting.
                      true));
  }
}; // end struct non_canonicalized_type_hash

/// The equality functor of for the set of non canonicalized types, aka
/// @ref nc_type_ptr_set_type
struct non_canonicalized_type_equal
{
  /// The equality operator.
  ///
  /// @param l the left-hand operand of the operation.
  ///
  /// @param r the right-hand operand of the operation.
  ///
  /// For now, two typedefs with different names but with the same
  /// underlying types are considered different.
  ///
  /// TODO: try making typedefs with different names hash the same if
  /// their underlying types are equal and see what breaks.
  //
  // @return true iff @p l equals @p r.
  bool
  operator()(const type_base *l, const type_base *r) const
  {
    ABG_ASSERT(is_non_canonicalized_type(l));
    ABG_ASSERT(is_non_canonicalized_type(r));

   return *l == *r;
  }
}; // end struct non_canonicalized_type_equal

// A convenience typedef for a set of type_base*.
typedef std::unordered_set<const type_base*> type_ptr_set_type;

/// A set meant to carry non canonicalized types.
///
/// Those types make the function is_non_canonicalized_type return
/// true.
typedef std::unordered_set<const type_base*,
               non_canonicalized_type_hash,
               non_canonicalized_type_equal>
nc_type_ptr_set_type;

/// A map meant to carry non canonicalized types as key.
///
/// Those types make the function is_non_canonicalized_type return
/// true.
typedef std::unordered_map<const type_base*, interned_string,
               non_canonicalized_type_hash,
               non_canonicalized_type_equal>
nc_type_ptr_istr_map_type;

/// A convenience typedef for a set of function type*.
typedef std::unordered_set<function_type*> fn_type_ptr_set_type;

struct function_tdecl_hash
{
  size_t operator()(const function_tdecl_sptr& f) const
  {return reinterpret_cast<size_t>(f.get());}
};

typedef unordered_map<function_tdecl_sptr,
              string, function_tdecl_hash>
fn_tmpl_shared_ptr_map;

struct class_tdecl_hash
{
  size_t operator()(const class_tdecl_sptr& c) const
  {return reinterpret_cast<size_t>(c.get());}
};

typedef unordered_map<class_tdecl_sptr,
              string,
              class_tdecl_hash> class_tmpl_shared_ptr_map;

class write_context
{
  const environment&            m_env;
  id_manager                m_id_manager;
  ostream*              m_ostream;
  bool                  m_annotate;
  bool                  m_show_locs;
  bool                  m_write_architecture;
  bool                  m_write_corpus_path;
  bool                  m_write_comp_dir;
  bool                  m_write_elf_needed;
  bool                  m_write_undefined_symbols;
  bool                  m_write_parameter_names;
  bool                  m_short_locs;
  bool                  m_write_default_sizes;
  type_id_style_kind            m_type_id_style;
  mutable type_ptr_map          m_type_id_map;
  // type id map for non-canonicalized types.
  mutable unordered_set<uint32_t>   m_used_type_id_hashes;
  mutable type_ptr_set_type     m_emitted_type_set;
  // A map of types that are referenced by emitted pointers,
  // references or typedefs
  type_ptr_set_type         m_referenced_types_set;
  fn_type_ptr_set_type          m_referenced_fn_types_set;
  fn_tmpl_shared_ptr_map        m_fn_tmpl_id_map;
  class_tmpl_shared_ptr_map     m_class_tmpl_id_map;
  string_elf_symbol_sptr_map_type   m_fun_symbol_map;
  string_elf_symbol_sptr_map_type   m_var_symbol_map;
  unordered_set<interned_string, hash_interned_string>  m_emitted_decls_set;
  unordered_set<string>             m_emitted_corpora_set;

  write_context();

public:

  /// Constructor.
  ///
  /// @param env the enviroment we are operating from.
  ///
  /// @param os the output stream to write to.
  write_context(const environment& env, ostream& os)
    : m_env(env),
      m_id_manager(env),
      m_ostream(&os),
      m_annotate(false),
      m_show_locs(true),
      m_write_architecture(true),
      m_write_corpus_path(true),
      m_write_comp_dir(true),
      m_write_elf_needed(true),
      m_write_undefined_symbols(true),
      m_write_parameter_names(true),
      m_short_locs(false),
      m_write_default_sizes(true),
      m_type_id_style(SEQUENCE_TYPE_ID_STYLE)
  {}

  /// Getter of the environment we are operating from.
  ///
  /// @return the environment we are operating from.
  const environment&
  get_environment() const
  {return m_env;}

  const config&
  get_config() const
  {return get_environment().get_config();}

  /// Getter for the current ostream
  ///
  /// @return a reference to the current ostream
  ostream&
  get_ostream()
  {return *m_ostream;}

  /// Setter for the current ostream
  ///
  /// @param os the new ostream
  void
  set_ostream(ostream& os)
  {m_ostream = &os;}

  /// Getter of the annotation option.
  ///
  /// @return true iff ABIXML annotations are turned on
  bool
  get_annotate()
  {return m_annotate;}

  /// Setter of the annotation option.
  ///
  /// @param f the new value of the flag.
  void
  set_annotate(bool f)
  {m_annotate = f;}

  /// Getter of the write-architecture option.
  ///
  /// @return true iff architecture information shall be emitted
  bool
  get_write_architecture()
  {return m_write_architecture;}

  /// Setter of the write-architecture option
  ///
  /// @param f the new value of the flag.
  void
  set_write_architecture(bool f)
  {m_write_architecture = f;}

  /// Getter of the elf-needed option.
  ///
  /// @return true iff elf needed information shall be emitted
  bool
  get_write_elf_needed()
  {return m_write_elf_needed;}

  /// Setter of the elf-needed option.
  ///
  /// @param f the new value of the flag.
  void
  set_write_elf_needed(bool f)
  {m_write_elf_needed = f;}

  /// Getter of the "undefined-symbols" option.
  ///
  /// @return true iff undefined symbols shall be emitted.
  bool
  get_write_undefined_symbols() const
  {return m_write_undefined_symbols;}

  /// Setter of the "undefined-symbols" option.
  ///
  /// @param f true iff undefined symbols shall be emitted.
  void
  set_write_undefined_symbols(bool f)
  {m_write_undefined_symbols = f;}

  /// Getter of the default-sizes option.
  ///
  /// @return true iff default size-in-bits needs to be emitted
  bool
  get_write_default_sizes()
  {return m_write_default_sizes;}

  /// Setter of the default-sizes option.
  ///
  /// @param f the new value of the flag.
  void
  set_write_default_sizes(bool f)
  {m_write_default_sizes = f;}

  /// Getter of the write-corpus-path option.
  ///
  /// @return true iff corpus-path information shall be emitted
  bool
  get_write_corpus_path()
  {return m_write_corpus_path;}

  /// Setter of the write-corpus-path option
  ///
  /// @param f the new value of the flag.
  void
  set_write_corpus_path(bool f)
  {m_write_corpus_path = f;}

  /// Getter of the comp-dir-path option.
  ///
  /// @return true iff compilation dir information shall be emitted
  bool
  get_write_comp_dir()
  {return m_write_comp_dir;}

  /// Setter of the comp-dir-path option
  ///
  /// @param f the new value of the flag.
  void
  set_write_comp_dir(bool f)
  {m_write_comp_dir = f;}

  /// Getter of the short-locs option.
  ///
  /// @return true iff short locations shall be emitted
  bool
  get_short_locs()
  {return m_short_locs;}

  /// Setter of the short-locs option
  ///
  /// @param f the new value of the flag.
  void
  set_short_locs(bool f)
  {m_short_locs = f;}

  /// Getter of the parameter-names option.
  ///
  /// @return true iff parameter names shall be emitted
  bool
  get_write_parameter_names() const
  {return m_write_parameter_names;}

  /// Setter of the parameter-names option
  ///
  /// @param f the new value of the flag.
  void
  set_write_parameter_names(bool f)
  {m_write_parameter_names = f;}

  /// Getter of the "show-locs" option.
  ///
  /// When this option is true then the XML writer emits location
  /// information for emitted ABI artifacts.
  ///
  /// @return the value of the "show-locs" option.
  bool
  get_show_locs() const
  {return m_show_locs;}

  /// Setter of the "show-locs" option.
  ///
  /// When this option is true then the XML writer emits location
  /// information for emitted ABI artifacts.
  ///
  /// @param f the new value of the "show-locs" option.
  void
  set_show_locs(bool f)
  {m_show_locs = f;}

  /// Getter of the "type-id-style" option.
  ///
  /// This option controls the kind of type ids used in XML output.
  ///
  /// @return the value of the "type-id-style" option.
  type_id_style_kind
  get_type_id_style() const
  {return m_type_id_style;}

  /// Setter of the "type-id-style" option.
  ///
  /// This option controls the kind of type ids used in XML output.
  ///
  /// @param style the new value of the "type-id-style" option.
  void
  set_type_id_style(type_id_style_kind style)
  {m_type_id_style = style;}

  /// Getter of the @ref id_manager.
  ///
  /// @return the @ref id_manager used by the current instance of @ref
  /// write_context.
  const id_manager&
  get_id_manager() const
  {return m_id_manager;}

  id_manager&
  get_id_manager()
  {return m_id_manager;}

  /// @return true iff type has already been assigned an ID.
  bool
  type_has_existing_id(type_base_sptr type) const
  {return type_has_existing_id(type.get());}

  /// @return true iff type has already been assigned an ID.
  bool
  type_has_existing_id(type_base* type) const
  {
    type = get_exemplar_type(type);
    return m_type_id_map.find(type) != m_type_id_map.end();
  }

  /// Associate a unique id to a given type.  For that, put the type
  /// in a hash table, hashing the type.  So if the type has no id
  /// associated to it, create a new one and return it.  Otherwise,
  /// return the existing id for that type.
  interned_string
  get_id_for_type(const type_base_sptr& t)
  {return get_id_for_type(t.get());}

  /// Associate a unique id to a given type.  For that, put the type
  /// in a hash table, hashing the type.  So if the type has no id
  /// associated to it, create a new one and return it.  Otherwise,
  /// return the existing id for that type.
  interned_string
  get_id_for_type(const type_base* type) const
  {
    type_base* c = get_exemplar_type(type);

    auto it = m_type_id_map.find(c);
    if (it != m_type_id_map.end())
      return it->second;

    switch (m_type_id_style)
      {
      case SEQUENCE_TYPE_ID_STYLE:
    {
      interned_string id = get_id_manager().get_id_with_prefix("type-id-");
      return m_type_id_map[c] = id;
    }
      case HASH_TYPE_ID_STYLE:
    {
      interned_string pretty = c->get_cached_pretty_representation(true);
      size_t hash = hashing::fnv_hash(pretty);
      while (!m_used_type_id_hashes.insert(hash).second)
        ++hash;
      std::ostringstream os;
      os << std::hex << std::setfill('0') << std::setw(8) << hash;
      return m_type_id_map[c] = c->get_environment().intern(os.str());
    }
      }
    ABG_ASSERT_NOT_REACHED;
    return interned_string();
  }

  string
  get_id_for_fn_tmpl(const function_tdecl_sptr& f)
  {
    fn_tmpl_shared_ptr_map::const_iterator it = m_fn_tmpl_id_map.find(f);
    if (it == m_fn_tmpl_id_map.end())
      {
    string id = get_id_manager().get_id_with_prefix("fn-tmpl-id-");
    m_fn_tmpl_id_map[f] = id;
    return id;
      }
    return m_fn_tmpl_id_map[f];
  }

  string
  get_id_for_class_tmpl(const class_tdecl_sptr& c)
  {
    class_tmpl_shared_ptr_map::const_iterator it = m_class_tmpl_id_map.find(c);
    if (it == m_class_tmpl_id_map.end())
      {
    string id = get_id_manager().get_id_with_prefix("class-tmpl-id-");
    m_class_tmpl_id_map[c] = id;
    return id;
      }
    return m_class_tmpl_id_map[c];
  }

  void
  clear_type_id_map()
  {
    m_type_id_map.clear();
  }


  /// Getter of the set of types that were referenced by a pointer,
  /// reference or typedef.
  ///
  /// This set contains only types that do have canonical types and
  /// which are not function types.
  ///
  /// @return the set of types that were referenced.
  const type_ptr_set_type&
  get_referenced_types() const
  {return m_referenced_types_set;}

  /// Getter of the set of function types that were referenced by a
  /// pointer, reference or typedef.
  ///
  /// @return the set of function types that were referenced.
  const fn_type_ptr_set_type&
  get_referenced_function_types() const
  {return m_referenced_fn_types_set;}

  /// Test if there are non emitted referenced types.
  ///
  /// @return true iff there are non emitted referenced types.
  bool
  has_non_emitted_referenced_types() const
  {
    for (const auto t : get_referenced_types())
      if (!type_is_emitted(t))
      return false;

    return true;
  }

  /// Record a given type as being referenced by a pointer, a
  /// reference or a typedef type that is being emitted to the XML
  /// output.
  ///
  /// @param t a shared pointer to a type
  void
  record_type_as_referenced(const type_base_sptr& type)
  {
    type_base* t = get_exemplar_type(type.get());
    // If the type is a function type, record it in a dedicated data
    // structure.
    if (function_type* f = is_function_type(t))
      m_referenced_fn_types_set.insert(f);
    else
      m_referenced_types_set.insert(t);
  }

  /// Test if a given type has been referenced by a pointer, a
  /// reference or a typedef type that was emitted to the XML output.
  ///
  /// @param f a shared pointer to a type
  ///
  /// @return true if the type has been referenced, false
  /// otherwise.
  bool
  type_is_referenced(const type_base_sptr& type)
  {
    type_base* t = get_exemplar_type(type.get());
    if (function_type* f = is_function_type(t))
      return (m_referenced_fn_types_set.find(f)
          != m_referenced_fn_types_set.end());
    else
      return m_referenced_types_set.find(t) != m_referenced_types_set.end();
  }

  /// Sort the content of a map of type pointers into a vector.
  ///
  /// The pointers are sorted by using their string representation as
  /// the key to sort, lexicographically.
  ///
  /// @param types the map to sort.
  ///
  /// @param sorted the resulted sorted vector.  It's set by this
  /// function with the result of the sorting.
  void
  sort_types(type_ptr_set_type& types,
         vector<type_base*>& sorted)
  {
    string id;
    for (type_ptr_set_type::const_iterator i = types.begin();
     i != types.end();
     ++i)
      sorted.push_back(const_cast<type_base*>(*i));
    type_topo_comp comp;
    sort(sorted.begin(), sorted.end(), comp);
  }

  /// Sort the content of a map of type pointers into a vector.
  ///
  /// The pointers are sorted by using their string representation as
  /// the key to sort, lexicographically.
  ///
  /// @param types the map to sort.
  ///
  /// @param sorted the resulted sorted vector.  It's set by this
  /// function with the result of the sorting.
  void
  sort_types(const istring_type_base_wptr_map_type& types,
         vector<type_base_sptr> &sorted)
  {
    for (istring_type_base_wptr_map_type::const_iterator i = types.begin();
     i != types.end();
     ++i)
      sorted.push_back(type_base_sptr(i->second));
    type_topo_comp comp;
    sort(sorted.begin(), sorted.end(), comp);
  }

  /// Sort the content of a vector of function types into a vector of
  /// types.
  ///
  /// The pointers are sorted by using their string representation as
  /// the key to sort, lexicographically.
  ///
  /// @param types the vector of function types to store.
  ///
  /// @param sorted the resulted sorted vector.  It's set by this
  /// function with the result of the sorting.
  void
  sort_types(const vector<function_type_sptr>& types,
         vector<type_base_sptr> &sorted)
  {
    for (vector<function_type_sptr>::const_iterator i = types.begin();
     i != types.end();
     ++i)
      sorted.push_back(*i);
    type_topo_comp comp;
    sort(sorted.begin(), sorted.end(), comp);
  }

  /// Flag a type as having been written out to the XML output.
  ///
  /// @param t the type to flag.
  void
  record_type_as_emitted(const type_base_sptr &t)
  {record_type_as_emitted(t.get());}

  /// Flag a type as having been written out to the XML output.
  ///
  /// @param t the type to flag.
  void
  record_type_as_emitted(const type_base* t)
  {
    type_base* c = get_exemplar_type(t);
    m_emitted_type_set.insert(c);
  }

  /// Test if a given type has been written out to the XML output.
  ///
  /// @param the type to test for.
  ///
  /// @return true if the type has already been emitted, false
  /// otherwise.
  bool
  type_is_emitted(const type_base* t) const
  {
    type_base* c = get_exemplar_type(t);
    return (m_emitted_type_set.find(c) != m_emitted_type_set.end());
  }

  /// Test if a given type has been written out to the XML output.
  ///
  /// @param the type to test for.
  ///
  /// @return true if the type has already been emitted, false
  /// otherwise.
  bool
  type_is_emitted(const type_base_sptr& t) const
  {return type_is_emitted(t.get());}

  /// Test if a given decl has been written out to the XML output.
  ///
  /// @param the decl to consider.
  ///
  /// @return true if the decl has already been emitted, false
  /// otherwise.
  bool
  decl_is_emitted(const decl_base& decl) const
  {
    string repr = decl.get_pretty_representation(true);
    interned_string irepr = decl.get_environment().intern(repr);
    return m_emitted_decls_set.find(irepr) != m_emitted_decls_set.end();
  }

  /// Test if a given decl has been written out to the XML output.
  ///
  /// @param the decl to consider.
  ///
  /// @return true if the decl has already been emitted, false
  /// otherwise.
  bool
  decl_is_emitted(const decl_base_sptr& decl) const
  {
    ABG_ASSERT(!is_type(decl));
    string repr = get_pretty_representation(decl, true);
    interned_string irepr = decl->get_environment().intern(repr);
    return m_emitted_decls_set.find(irepr) != m_emitted_decls_set.end();
  }

  /// Record a declaration as emitted in the abixml output.
  ///
  /// @param decl the decl to consider.
  void
  record_decl_as_emitted(const decl_base_sptr& decl)
  {
    string repr = get_pretty_representation(decl, true);
    interned_string irepr = decl->get_environment().intern(repr);
    m_emitted_decls_set.insert(irepr);
  }

  /// Test if a corpus has already been emitted.
  ///
  /// A corpus is emitted if it's been recorded as having been emitted
  /// by the function record_corpus_as_emitted().
  ///
  /// @param corp the corpus to consider.
  ///
  /// @return true iff the corpus @p corp has been emitted.
  bool
  corpus_is_emitted(const corpus_sptr& corp)
  {
    if (!corp)
      return false;

    if (m_emitted_corpora_set.find(corp->get_path())
    == m_emitted_corpora_set.end())
      return false;

    return true;
  }

  /// Record the corpus has having been emitted.
  ///
  /// @param corp the corpus to consider.
  void
  record_corpus_as_emitted(const corpus_sptr& corp)
  {
    if (!corp)
      return;

    const string& path = corp->get_path();
    if (!path.empty())
      m_emitted_corpora_set.insert(path);
  }

  /// Get the set of types that have been emitted.
  ///
  /// @return the set of types that have been emitted.
  const type_ptr_set_type&
  get_emitted_types_set() const
  {return m_emitted_type_set;}

  /// Clear the map that contains the IDs of the types that has been
  /// recorded as having been written out to the XML output.
  void
  clear_referenced_types()
  {
    m_referenced_types_set.clear();
    m_referenced_fn_types_set.clear();
  }

  const string_elf_symbol_sptr_map_type&
  get_fun_symbol_map() const
  {return m_fun_symbol_map;}

  string_elf_symbol_sptr_map_type&
  get_fun_symbol_map()
  {return m_fun_symbol_map;}

};//end write_context

static void write_location(const location&, write_context&);
static void write_location(const decl_base_sptr&, write_context&);
static bool write_visibility(const decl_base_sptr&, ostream&);
static bool write_binding(const decl_base_sptr&, ostream&);
static bool write_is_artificial(const decl_base_sptr&, ostream&);
static bool write_is_non_reachable(const type_base_sptr&, ostream&);
static bool write_tracking_non_reachable_types(const corpus_sptr&, ostream&);
static void write_array_size_and_alignment(const array_type_def_sptr,
                       ostream&);
static void write_size_and_alignment(const type_base_sptr, ostream&,
                     size_t default_size = 0,
                     size_t default_alignment = 0);
static void write_access(access_specifier, ostream&);
static void write_layout_offset(var_decl_sptr, ostream&);
static void write_layout_offset(class_decl::base_spec_sptr, ostream&);
static void write_cdtor_const_static(bool, bool, bool, bool, ostream&);
static void write_voffset(function_decl_sptr, ostream&);
static void write_elf_symbol_type(elf_symbol::type, ostream&);
static void write_elf_symbol_binding(elf_symbol::binding, ostream&);
static bool write_elf_symbol_aliases(const elf_symbol&, ostream&);
static bool write_elf_symbol_reference(write_context&,
                       const elf_symbol&,
                       const corpus& abi,
                       ostream&);
static bool write_elf_symbol_reference(write_context&,
                       const elf_symbol_sptr,
                       const corpus& abi,
                       ostream&);
static void write_is_declaration_only(const decl_base_sptr&, ostream&);
static void write_is_struct(const class_decl_sptr&, ostream&);
static void write_is_anonymous(const decl_base_sptr&, ostream&);
static void write_type_hash_and_cti(const type_base_sptr&, ostream&);
static void write_naming_typedef(const decl_base_sptr&, write_context&);
static bool write_decl(const decl_base_sptr&, write_context&, unsigned);
static void write_decl_in_scope(const decl_base_sptr&,
                write_context&, unsigned);
static bool write_type_decl(const type_decl_sptr&, write_context&, unsigned);
static bool write_namespace_decl(const namespace_decl_sptr&,
                 write_context&, unsigned);
static bool write_qualified_type_def(const qualified_type_def_sptr&,
                     write_context&, unsigned);
static bool write_pointer_type_def(const pointer_type_def_sptr&,
                   write_context&, unsigned);
static bool write_reference_type_def(const reference_type_def_sptr&,
                     write_context&, unsigned);
static bool write_ptr_to_mbr_type(const ptr_to_mbr_type_sptr&,
                  write_context&, unsigned);
static bool write_array_type_def(const array_type_def_sptr&,
                     write_context&, unsigned);
static bool write_array_subrange_type(const array_type_def::subrange_sptr&,
                      write_context&,
                      unsigned);
static bool write_enum_type_decl(const enum_type_decl_sptr&,
                 write_context&, unsigned);
static bool write_typedef_decl(const typedef_decl_sptr&,
                   write_context&, unsigned);
static bool write_elf_symbol(const elf_symbol_sptr&,
                 write_context&, unsigned);
static bool write_elf_symbols_table(const elf_symbols&,
                    write_context&, unsigned);
static bool write_var_decl(const var_decl_sptr&,
               write_context&, bool, unsigned);
static bool write_function_decl(const function_decl_sptr&,
                write_context&, bool, unsigned);
static bool write_function_type(const function_type_sptr&,
                write_context&, unsigned);
static bool write_member_type_opening_tag(const type_base_sptr&,
                      write_context&, unsigned);
static bool write_member_type(const type_base_sptr&,
                  write_context&, unsigned);
static bool write_class_decl_opening_tag(const class_decl_sptr&, const string&,
                     write_context&, unsigned, bool);
static bool write_class_decl(const class_decl_sptr&,
                 write_context&, unsigned);
static bool write_union_decl_opening_tag(const union_decl_sptr&, const string&,
                     write_context&, unsigned, bool);
static bool write_union_decl(const union_decl_sptr&, const string&,
                 write_context&, unsigned);
static bool write_union_decl(const union_decl_sptr&, write_context&, unsigned);
static void write_common_type_info(const type_base_sptr&, write_context&,
                   const string& id="");
static bool write_type(const type_base_sptr&, write_context&, unsigned);
static bool write_type_tparameter
(const shared_ptr<type_tparameter>, write_context&, unsigned);
static bool write_non_type_tparameter
(const shared_ptr<non_type_tparameter>, write_context&, unsigned);
static bool write_template_tparameter
(const shared_ptr<template_tparameter>, write_context&, unsigned);
static bool write_type_composition
(const shared_ptr<type_composition>, write_context&, unsigned);
static bool write_template_parameter(const shared_ptr<template_parameter>,
                     write_context&, unsigned);
static void write_template_parameters(const shared_ptr<template_decl>,
                      write_context&, unsigned);
static bool write_function_tdecl
(const shared_ptr<function_tdecl>,
 write_context&, unsigned);
static bool write_class_tdecl
(const shared_ptr<class_tdecl>,
 write_context&, unsigned);
static void do_indent(ostream&, unsigned);
static void do_indent_to_level(write_context&, unsigned, unsigned);
static unsigned get_indent_to_level(write_context&, unsigned, unsigned);

/// Emit nb_whitespaces white spaces into the output stream.
void
do_indent(ostream& o, unsigned nb_whitespaces)
{
  for (unsigned i = 0; i < nb_whitespaces; ++i)
    o << ' ';
}

/// Indent initial_indent + level number of xml element indentation.
///
/// @param ctxt the context of the parsing.
///
/// @param initial_indent the initial number of white space to indent to.
///
/// @param level the number of indentation level to indent to.
static void
do_indent_to_level(write_context& ctxt,
           unsigned initial_indent,
           unsigned level)
{
  do_indent(ctxt.get_ostream(),
        get_indent_to_level(ctxt, initial_indent, level));
}

/// Return the number of white space of indentation that
/// #do_indent_to_level would have used.
///
/// @param ctxt the context of the parsing.
///
/// @param initial_indent the initial number of white space to indent to.
///
/// @param level the number of indentation level to indent to.
static unsigned
get_indent_to_level(write_context& ctxt, unsigned initial_indent,
            unsigned level)
{
    int nb_ws = initial_indent +
      level * ctxt.get_config().get_xml_element_indent();
    return nb_ws;
}

/// Annotate a declaration in form of an ABIXML comment.
///
/// This function is further specialized for declarations and types
/// with special requirements.
///
/// @tparam T shall be of type decl_base_sptr or a shared pointer to a
/// type derived from it, for the instantiation to be syntactically
/// correct.
///
/// @param decl_sptr the shared pointer to the declaration of type T.
///
/// @param ctxt the context of the parsing.
///
/// @param indent the amount of white space to indent to.
///
/// @return true iff decl is valid.
template <typename T>
static bool
annotate(const T&   decl,
     write_context& ctxt,
     unsigned   indent)
{
  if (!decl)
    return false;

  if (!ctxt.get_annotate())
    return true;

  ostream& o = ctxt.get_ostream();

  do_indent(o, indent);

  o << "<!-- "
    << xml::escape_xml_comment(decl->get_pretty_representation(/*internal=*/false))
    << " -->\n";

  return true;
}

/// Annotate an elf symbol in form of an ABIXML comment, effectively
/// writing out its demangled form.
///
/// @param sym the symbol, whose name should be demangled.
///
/// @param ctxt the context of the parsing.
///
/// @param indent the amount of white space to indent to.
///
/// @return true iff decl is valid
template<>
bool
annotate(const elf_symbol_sptr& sym,
     write_context& ctxt,
     unsigned       indent)
{
  if (!sym)
    return false;

  if (!ctxt.get_annotate())
    return true;

  ostream& o = ctxt.get_ostream();

  do_indent(o, indent);
  o << "<!-- "
    << xml::escape_xml_comment(abigail::ir::demangle_cplus_mangled_name(sym->get_name()))
    << " -->\n";

  return true;
}

/// Annotate a typedef declaration in form of an ABIXML comment.
///
/// @param typedef_decl the typedef to annotate.
///
/// @param ctxt the context of the parsing.
///
/// @param indent the amount of white space to indent to.
///
/// @return true iff decl is valid
template<>
bool
annotate(const typedef_decl_sptr&   typedef_decl,
     write_context&     ctxt,
     unsigned           indent)
{
  if (!typedef_decl)
    return false;

  if (!ctxt.get_annotate())
    return true;

  ostream& o = ctxt.get_ostream();

  do_indent(o, indent);

  o << "<!-- typedef "
    << get_type_name(typedef_decl->get_underlying_type())
    << " "
    << get_type_name(typedef_decl)
    << " -->\n";

  return true;
}

/// Annotate a function type in form of an ABIXML comment.
///
/// @param function_type the function type to annotate.
///
/// @param ctxt the context of the parsing.
///
/// @param indent the amount of white space to indent to.
///
/// @param skip_first_parm if true, do not serialize the first
/// parameter of the function decl.
//
/// @return true iff decl is valid
bool
annotate(const function_type_sptr&  function_type,
     write_context&     ctxt,
     unsigned           indent)
{
  if (!function_type)
    return false;

  if (!ctxt.get_annotate())
    return true;

  ostream& o = ctxt.get_ostream();

  do_indent(o, indent);

  o << "<!-- "
    << xml::escape_xml_comment(get_function_type_name(function_type))
    << " -->\n";
  return true;
}

/// Annotate a function declaration in form of an ABIXML comment.
///
/// @param fn the function decl to annotate.
///
/// @param ctxt the context of the parsing.
///
/// @param indent the amount of white space to indent to.
///
/// @param skip_first_parm if true, do not serialize the first
/// parameter of the function decl.
//
/// @return true iff decl is valid
static bool
annotate(const function_decl_sptr&  fn,
     write_context&     ctxt,
     unsigned           indent)
{
  if (!fn)
    return false;

  if (!ctxt.get_annotate())
    return true;

  ostream& o = ctxt.get_ostream();

  do_indent(o, indent);
  o << "<!-- ";

  if (is_member_function(fn)
      && (get_member_function_is_ctor(fn) || get_member_function_is_dtor(fn)))
    ; // we don't emit return types for ctor or dtors
  else
    o << xml::escape_xml_comment(get_type_name(fn->get_return_type()))
      << " ";

  o << xml::escape_xml_comment(fn->get_qualified_name()) << "(";

  vector<function_decl::parameter_sptr>::const_iterator pi =
    fn->get_first_non_implicit_parm();

  for (; pi != fn->get_parameters().end(); ++pi)
    {
      o << xml::escape_xml_comment((*pi)->get_type_name());
      // emit a comma after a param type, unless it's the last one
      if (distance(pi, fn->get_parameters().end()) > 1)
    o << ", ";
    }
  o << ") -->\n";

  return true;
}

/// Annotate a function parameter in form of an ABIXML comment.
///
/// @param parm the function parameter to annotate.
///
/// @param ctxt the context of the parsing.
///
/// @param indent the amount of white space to indent to.
///
/// @return true iff decl is valid
template<>
bool
annotate(const function_decl::parameter_sptr&   parm,
     write_context&         ctxt,
     unsigned               indent)
{
  if (!parm)
    return false;

  if (!ctxt.get_annotate())
    return true;

  ostream &o = ctxt.get_ostream();

  do_indent(o, indent);

  o << "<!-- ";

  if (parm->get_variadic_marker())
    o << "variadic parameter";
  else
    {
      if (parm->get_is_artificial())
    {
      if (parm->get_index() == 0)
        o << "implicit ";
      else
        o << "artificial ";
    }
      o << "parameter of type '"
    << xml::escape_xml_comment(get_pretty_representation(parm->get_type()));
    }

  o << "' -->\n";

  return true;
}

/// Write a location to the output stream.
///
/// If the location is empty, nothing is written.
///
/// @param loc the location to consider.
///
/// @param tu the translation unit the location belongs to.
///
/// @param ctxt the writer context to use.
static void
write_location(const location& loc, write_context& ctxt)
{
  if (!loc || loc.get_is_artificial())
    return;

  if (!ctxt.get_show_locs())
    return;

  string filepath;
  unsigned line = 0, column = 0;

  loc.expand(filepath, line, column);

  ostream &o = ctxt.get_ostream();

  if (ctxt.get_short_locs())
    tools_utils::base_name(filepath, filepath);

  o << " filepath='" << xml::escape_xml_string(filepath) << "'"
    << " line='"     << line     << "'"
    << " column='"   << column   << "'";
}

/// Write the location of a decl to the output stream.
///
/// If the location is empty, nothing is written.
///
/// @param decl the decl to consider.
///
/// @param ctxt the @ref writer_context to use.
static void
write_location(const decl_base_sptr&    decl,
           write_context&       ctxt)
{
  if (!decl)
    return;

  location loc = decl->get_location();
  if (!loc)
    return;

  write_location(loc, ctxt);
}

/// Serialize the visibility property of the current decl as the
/// 'visibility' attribute for the current xml element.
///
/// @param decl the instance of decl_base to consider.
///
/// @param o the output stream to serialize the property to.
///
/// @return true upon successful completion, false otherwise.
static bool
write_visibility(const shared_ptr<decl_base>&   decl, ostream& o)
{
  if (!decl)
    return false;

  decl_base::visibility v = decl->get_visibility();
  string str;

  switch (v)
    {
    case decl_base::VISIBILITY_NONE:
      return true;
    case decl_base::VISIBILITY_DEFAULT:
      str = "default";
      break;
    case decl_base::VISIBILITY_PROTECTED:
      str = "protected";
      break;
    case decl_base::VISIBILITY_HIDDEN:
      str = "hidden";
      break;
    case decl_base::VISIBILITY_INTERNAL:
    str = "internal";
    break;
    }

  if (str.empty())
    return false;

  o << " visibility='" << str << "'";

  return true;
}

/// Serialize the 'binding' property of the current decl.
///
/// @param decl the decl to consider.
///
/// @param o the output stream to serialize the property to.
static bool
write_binding(const shared_ptr<decl_base>& decl, ostream& o)
{
  if (!decl)
    return false;

  decl_base::binding bind = decl_base::BINDING_NONE;

  shared_ptr<var_decl> var =
    dynamic_pointer_cast<var_decl>(decl);
  if (var)
    bind = var->get_binding();
  else
    {
      shared_ptr<function_decl> fun =
    dynamic_pointer_cast<function_decl>(decl);
      if (fun)
    bind = fun->get_binding();
    }

  string str;
  switch (bind)
    {
    case decl_base::BINDING_NONE:
      break;
    case decl_base::BINDING_LOCAL:
      str = "local";
      break;
    case decl_base::BINDING_GLOBAL:
    str = "global";
      break;
    case decl_base::BINDING_WEAK:
      str = "weak";
      break;
    }

  if (!str.empty())
    o << " binding='" << str << "'";

  return true;
}

/// Write the "is-artificial" attribute of the @ref decl.
///
/// @param decl the declaration to consider.
///
/// @param o the output stream to emit the "is-artificial" attribute
/// to.
///
/// @return true iff the "is-artificial" attribute was emitted.
static bool
write_is_artificial(const decl_base_sptr& decl, ostream& o)
{
  if (!decl)
    return false;

  if (decl->get_is_artificial())
    o << " is-artificial='yes'";

  return true;
}

/// Write the 'is-non-reachable' attribute if a given type we are
/// looking at is not reachable from global functions and variables
/// and if the user asked us to track that information.
///
/// @param t the type to consider.
///
/// @param o the output stream to write the 'is-non-reachable'
/// attribute to.
static bool
write_is_non_reachable(const type_base_sptr& t, ostream& o)
{
  if (!t)
    return false;

  corpus* c = t->get_corpus();
  if (!c)
    return false;

  if (!c->recording_types_reachable_from_public_interface_supported()
      || c->type_is_reachable_from_public_interfaces(*t))
    return false;

  o << " is-non-reachable='yes'";

  return true;
}

/// Write the 'tracking-non-reachable-types' attribute if for a given
/// corpus, the user wants us to track non-reachable types.
///
/// @param corpus the ABI corpus to consider.
///
/// @param o the output parameter to write the
/// 'tracking-non-reachable-types' attribute to.
static bool
write_tracking_non_reachable_types(const corpus_sptr& corpus,
                   ostream& o)
{
  corpus_group* group = corpus->get_group();
  if (!group)
    if (corpus->recording_types_reachable_from_public_interface_supported())
      {
    o << " tracking-non-reachable-types='yes'";
    return true;
      }

  return false;
}

/// Serialize the size and alignment attributes of a given type.
///
/// @param decl the type to consider.
///
/// @param o the output stream to serialize to.
///
/// @param default_size size in bits that is the default for the type.
///                     No size-in-bits attribute is written if it
///                     would be the default value.
///
/// @param default_alignment alignment in bits that is the default for
///                     the type.  No alignment-in-bits attribute is
///                     written if it would be the default value.
static void
write_size_and_alignment(const shared_ptr<type_base> decl, ostream& o,
             size_t default_size, size_t default_alignment)
{
  size_t size_in_bits = decl->get_size_in_bits();
  if (size_in_bits != default_size)
    o << " size-in-bits='" << size_in_bits << "'";

  size_t alignment_in_bits = decl->get_alignment_in_bits();
  if (alignment_in_bits != default_alignment)
    o << " alignment-in-bits='" << alignment_in_bits << "'";
}

/// Serialize the size and alignment attributes of a given type.
/// @param decl the type to consider.
///
/// @param o the output stream to serialize to.
static void
write_array_size_and_alignment(const shared_ptr<array_type_def> decl, ostream& o)
{
  if (decl->is_non_finite())
    o << " size-in-bits='" << "unknown" << "'";
  else {
    size_t size_in_bits = decl->get_size_in_bits();
    if (size_in_bits)
      o << " size-in-bits='" << size_in_bits << "'";
  }

  size_t alignment_in_bits = decl->get_alignment_in_bits();
  if (alignment_in_bits)
    o << " alignment-in-bits='" << alignment_in_bits << "'";
}
/// Serialize the access specifier.
///
/// @param a the access specifier to serialize.
///
/// @param o the output stream to serialize it to.
static void
write_access(access_specifier a, ostream& o)
{
  string access_str = "private";

  switch (a)
    {
    case private_access:
      access_str = "private";
      break;

    case protected_access:
      access_str = "protected";
      break;

    case public_access:
      access_str = "public";
      break;

    default:
      break;
    }

  o << " access='" << access_str << "'";
}

/// Serialize the layout offset of a data member.
static void
write_layout_offset(var_decl_sptr member, ostream& o)
{
  if (!is_data_member(member))
    return;

  if (get_data_member_is_laid_out(member))
    o << " layout-offset-in-bits='"
      << get_data_member_offset(member)
      << "'";
}

/// Serialize the layout offset of a base class
static void
write_layout_offset(shared_ptr<class_decl::base_spec> base, ostream& o)
{
  if (!base)
    return;

  if (base->get_offset_in_bits() >= 0)
    o << " layout-offset-in-bits='" << base->get_offset_in_bits() << "'";
}

/// Serialize the access specifier of a class member.
///
/// @param member a pointer to the class member to consider.
///
/// @param o the ostream to serialize the member to.
static void
write_access(decl_base_sptr member, ostream& o)
{write_access(get_member_access_specifier(member), o);}

/// Write the voffset of a member function if it's non-zero
///
/// @param fn the member function to consider
///
/// @param o the output stream to write to
static void
write_voffset(function_decl_sptr fn, ostream&o)
{
  if (!fn)
    return;

  if (get_member_function_is_virtual(fn))
    {
      ssize_t voffset = get_member_function_vtable_offset(fn);
      o << " vtable-offset='" << voffset << "'";
    }
}

/// Serialize an elf_symbol::type into an XML node attribute named
/// 'type'.
///
/// @param t the elf_symbol::type to serialize.
///
/// @param o the output stream to serialize it to.
static void
write_elf_symbol_type(elf_symbol::type t, ostream& o)
{
  string repr;

  switch (t)
    {
    case elf_symbol::NOTYPE_TYPE:
      repr = "no-type";
      break;
    case elf_symbol::OBJECT_TYPE:
      repr = "object-type";
      break;
    case elf_symbol::FUNC_TYPE:
      repr = "func-type";
      break;
    case elf_symbol::SECTION_TYPE:
      repr = "section-type";
      break;
    case elf_symbol::FILE_TYPE:
      repr = "file-type";
      break;
    case elf_symbol::COMMON_TYPE:
      repr = "common-type";
      break;
    case elf_symbol::TLS_TYPE:
      repr = "tls-type";
      break;
    case elf_symbol::GNU_IFUNC_TYPE:
      repr = "gnu-ifunc-type";
      break;
    default:
      repr = "no-type";
      break;
    }

  o << " type='" << repr << "'";
}

/// Serialize an elf_symbol::binding into an XML element attribute of
/// name 'binding'.
///
/// @param b the elf_symbol::binding to serialize.
///
/// @param o the output stream to serialize the binding to.
static void
write_elf_symbol_binding(elf_symbol::binding b, ostream& o)
{
  string repr;

  switch (b)
    {
    case elf_symbol::LOCAL_BINDING:
      repr = "local-binding";
      break;
    case elf_symbol::GLOBAL_BINDING:
      repr = "global-binding";
      break;
    case elf_symbol::WEAK_BINDING:
      repr = "weak-binding";
      break;
    case elf_symbol::GNU_UNIQUE_BINDING:
      repr = "gnu-unique-binding";
      break;
    default:
      repr = "no-binding";
      break;
    }

  o << " binding='" << repr << "'";
}

/// Serialize an elf_symbol::binding into an XML element attribute of
/// name 'binding'.
///
/// @param b the elf_symbol::binding to serialize.
///
/// @param o the output stream to serialize the binding to.
static void
write_elf_symbol_visibility(elf_symbol::visibility v, ostream& o)
{
  string repr;

  switch (v)
    {
    case elf_symbol::DEFAULT_VISIBILITY:
      repr = "default-visibility";
      break;
    case elf_symbol::PROTECTED_VISIBILITY:
      repr = "protected-visibility";
      break;
    case elf_symbol::HIDDEN_VISIBILITY:
      repr = "hidden-visibility";
      break;
    case elf_symbol::INTERNAL_VISIBILITY:
      repr = "internal-visibility";
      break;
    default:
      repr = "default-visibility";
      break;
    }

  o << " visibility='" << repr << "'";
}

/// Write alias attributes for the aliases of a given symbol.
///
/// @param sym the symbol to write the attributes for.
///
/// @param o the output stream to write the attributes to.
///
/// @return true upon successful completion.
static bool
write_elf_symbol_aliases(const elf_symbol& sym, ostream& out)
{
  if (!sym.is_main_symbol() || !sym.has_aliases())
    return false;


  std::vector<std::string> aliases;
  for (elf_symbol_sptr s = sym.get_next_alias(); s && !s->is_main_symbol();
       s = s->get_next_alias())
    {
      if (!s->is_public())
    continue;

      if (s->is_suppressed())
    continue;

      if (sym.is_in_ksymtab() != s->is_in_ksymtab())
    continue;

      aliases.push_back(s->get_id_string());
    }

  if (!aliases.empty())
    {
      out << " alias='";
      std::string separator;
      for (const auto& alias : aliases)
    {
      out << separator << alias;
      separator = ",";
    }

      out << "'";
      return true;
    }

  return false;
}

/// Write an XML attribute for the reference to a symbol for the
/// current decl.
///
///
/// @param ctxt the current write context to consider.
///
/// @param sym the symbol to consider.
///
/// @param abi the ABI corpus the symbol @p sym is supposed to belong
/// to.  If the symbol doesn't belong to that corpus, then the
/// reference is not be emitted.
///
/// @param o the output stream to write the attribute to.
///
/// @return true upon successful completion.
static bool
write_elf_symbol_reference(write_context& ctxt,
               const elf_symbol& sym,
               const corpus& abi,
               ostream& o)
{
  elf_symbol_sptr s = abi.lookup_function_symbol(sym);
  if (!s)
    s = abi.lookup_variable_symbol(sym);

  if (// If that symbol wasn't found in the current corpus ...
      !s
      // ... or we were NOT asked to represent undefined symbols and
      // yet that symbol is undefined ...
      || (!ctxt.get_write_undefined_symbols() && !s->is_defined()))
    // Then do not emit this symbol reference.
    return false;

  const elf_symbol* main = sym.get_main_symbol().get();
  const elf_symbol* alias = &sym;
  bool found = !alias->is_suppressed();
  // If the symbol itself is suppressed, check the alias chain.
  if (!found)
    {
      alias = main;
      found = !alias->is_suppressed();
    }
  // If the main symbol is suppressed, search the remainder of the chain.
  while (!found)
    {
      alias = alias->get_next_alias().get();
      // Two separate termination conditions at present.
      if (!alias || alias == main)
        break;
      found = !alias->is_suppressed();
    }
  // If all aliases are suppressed, just stick with the main symbol.
  if (!found)
    alias = main;
  o << " elf-symbol-id='"
    << xml::escape_xml_string(alias->get_id_string())
    << "'";
  return true;
}

/// Write an XML attribute for the reference to a symbol for the
/// current decl.
///
/// @param ctxt the write context to consider.
/// 
/// @param sym the symbol to consider.
///
/// @param abi the ABI corpus the symbol @p sym is supposed to belong
/// to.  If the symbol doesn't belong to that corpus, then the
/// reference is not be emitted.
///
/// @param o the output stream to write the attribute to.
///
/// @return true upon successful completion.
static bool
write_elf_symbol_reference(write_context& ctxt,
               const elf_symbol_sptr sym,
               const corpus& abi,
               ostream& o)
{
  if (!sym)
    return false;

  return write_elf_symbol_reference(ctxt, *sym, abi, o);
}

/// Serialize the attributes "constructor", "destructor" or "static"
/// if they have true value.
///
/// @param is_ctor if set to true, the "constructor='true'" string is
/// emitted.
///
/// @param is_dtor if set to true the "destructor='true' string is
/// emitted.
///
/// @param is_static if set to true the "static='true'" string is
/// emitted.
///
/// @param o the output stream to use for the serialization.
static void
write_cdtor_const_static(bool is_ctor,
             bool is_dtor,
             bool is_const,
             bool is_static,
             ostream& o)
{
  if (is_static)
    o << " static='yes'";
  if (is_ctor)
    o << " constructor='yes'";
  else if (is_dtor)
    o << " destructor='yes'";
  if (is_const)
    o << " const='yes'";
}

/// Serialize the attribute "is-declaration-only", if the
/// decl_base_sptr has its 'is_declaration_only property set.
///
/// @param t the pointer to instance of @ref decl_base to consider.
///
/// @param o the output stream to serialize to.
static void
write_is_declaration_only(const decl_base_sptr& d, ostream& o)
{
  if (d->get_is_declaration_only())
    o << " is-declaration-only='yes'";
}

/// Serialize the attribute "is-struct", if the current instance of
/// class_decl is a struct.
///
/// @param klass a pointer to the instance of class_decl to consider.
///
/// @param o the output stream to serialize to.
static void
write_is_struct(const class_decl_sptr& klass, ostream& o)
{
  if (klass->is_struct())
    o << " is-struct='yes'";
}

/// Serialize the attribute "is-anonymous", if the current instance of
/// decl is anonymous
///
/// @param dcl a pointer to the instance of @ref decl_base to consider.
///
/// @param o the output stream to serialize to.
static void
write_is_anonymous(const decl_base_sptr& decl, ostream& o)
{
  if (decl->get_is_anonymous())
    o << " is-anonymous='yes'";
}

/// Emit the hash value and the canonical type index of a given type.
///
/// @param t the type to consider.
///
/// @param o the output stream to emit the hash to.
static void
write_type_hash_and_cti(const type_base_sptr& t, ostream& o)
{
  hash_t hash = t->hash_value();
  if (hash)
    {
      string h;
      ABG_ASSERT(hashing::serialize_hash(*hash, h));
      o << " hash='" << h;
      if (t->priv_->canonical_type_index)
    o << "#" << t->priv_->canonical_type_index;
      o << "'";
    }
}

/// Serialize the "naming-typedef-id" attribute, if the current
/// instance of @ref class_decl has a naming typedef.
///
/// @param klass the @ref class_decl to consider.
///
/// @param ctxt the write context to use.
static void
write_naming_typedef(const decl_base_sptr& decl, write_context& ctxt)
{
  if (!decl)
    return;

  ostream &o = ctxt.get_ostream();

  if (typedef_decl_sptr typedef_type = decl->get_naming_typedef())
    {
      string id = ctxt.get_id_for_type(typedef_type);
      o << " naming-typedef-id='" << id << "'";
      ctxt.record_type_as_referenced(typedef_type);
    }
}

/// Emit several XML properties related to type IR nodes.
///
/// @param t the type IR node to emit the XML properties for.
///
/// @param ctxt the write context to use.
///
/// @param id the type-ID to use in the XML properties emitted.
static void
write_common_type_info(const type_base_sptr& t,
               write_context& ctxt,
               const string& id)
{
  decl_base_sptr d = is_decl(t);

  ostream& o = ctxt.get_ostream();

  if (!d || (d && !d->get_is_declaration_only()))
    {
      if (!is_qualified_type(t) && !is_array_type(t))
    write_size_and_alignment(t, o);
      else if (array_type_def_sptr a = is_array_type(t))
    write_array_size_and_alignment(a, o);
    }

  if (d)
    {
      write_is_anonymous(d, o);
      write_is_declaration_only(d, o);
      write_location(d, ctxt);
    }

  write_type_hash_and_cti(t, o);

  string i = id;
  if (i.empty())
    i = ctxt.get_id_for_type(t);
  o << " id='" << i << "'";

  ctxt.record_type_as_emitted(t);
}

/// Helper to serialize a type artifact.
///
/// @param type the type to serialize.
///
/// @param ctxt the @ref write_context to use.
///
/// @param indent the number of white space to use for indentation.
///
/// @return true upon successful completion.
static bool
write_type(const type_base_sptr& type, write_context& ctxt, unsigned indent)
{
  if (write_type_decl(dynamic_pointer_cast<type_decl> (type),
              ctxt, indent)
      || write_qualified_type_def (dynamic_pointer_cast<qualified_type_def>
                   (type),
                   ctxt, indent)
      || write_pointer_type_def(dynamic_pointer_cast<pointer_type_def>(type),
                ctxt, indent)
      || write_reference_type_def(dynamic_pointer_cast
                  <reference_type_def>(type), ctxt, indent)
      || write_ptr_to_mbr_type(dynamic_pointer_cast
                   <ptr_to_mbr_type>(type),
                   ctxt, indent)
      || write_array_type_def(dynamic_pointer_cast
                  <array_type_def>(type), ctxt, indent)
      || write_enum_type_decl(dynamic_pointer_cast<enum_type_decl>(type),
                  ctxt, indent)
      || write_typedef_decl(dynamic_pointer_cast<typedef_decl>(type),
                ctxt, indent)
      || write_class_decl(is_class_type(type), ctxt, indent)
      || write_union_decl(is_union_type(type), ctxt, indent)
      || (write_function_tdecl
      (dynamic_pointer_cast<function_tdecl>(type), ctxt, indent))
      || (write_class_tdecl
      (dynamic_pointer_cast<class_tdecl>(type), ctxt, indent)))
    return true;

  return false;
}

/// Serialize a pointer to an of decl_base into an output stream.
///
/// @param decl the pointer to decl_base to serialize
///
/// @param ctxt the context of the serialization.  It contains e.g, the
/// output stream to serialize to.
///
/// @param indent how many indentation spaces to use during the
/// serialization.
///
/// @return true upon successful completion, false otherwise.
static bool
write_decl(const decl_base_sptr& decl, write_context& ctxt, unsigned indent)
{
  if (write_type_decl(dynamic_pointer_cast<type_decl> (decl),
              ctxt, indent)
      || write_namespace_decl(dynamic_pointer_cast<namespace_decl>(decl),
                  ctxt, indent)
      || write_qualified_type_def (dynamic_pointer_cast<qualified_type_def>
                   (decl),
                   ctxt, indent)
      || write_pointer_type_def(dynamic_pointer_cast<pointer_type_def>(decl),
                ctxt, indent)
      || write_reference_type_def(dynamic_pointer_cast
                  <reference_type_def>(decl), ctxt, indent)
      || write_ptr_to_mbr_type(dynamic_pointer_cast
                   <ptr_to_mbr_type>(decl),
                   ctxt, indent)
      || write_array_type_def(dynamic_pointer_cast
                  <array_type_def>(decl), ctxt, indent)
      || write_array_subrange_type(dynamic_pointer_cast
                   <array_type_def::subrange_type>(decl),
                   ctxt, indent)
      || write_enum_type_decl(dynamic_pointer_cast<enum_type_decl>(decl),
                  ctxt, indent)
      || write_typedef_decl(dynamic_pointer_cast<typedef_decl>(decl),
                ctxt, indent)
      || write_var_decl(dynamic_pointer_cast<var_decl>(decl), ctxt,
            /*write_linkage_name=*/true, indent)
      || write_function_decl(dynamic_pointer_cast<method_decl>
                 (decl), ctxt, /*skip_first_parameter=*/true,
                 indent)
      || write_function_decl(dynamic_pointer_cast<function_decl>(decl),
                 ctxt, /*skip_first_parameter=*/false, indent)
      || write_class_decl(is_class_type(decl), ctxt, indent)
      || write_union_decl(is_union_type(decl), ctxt, indent)
      || (write_function_tdecl
      (dynamic_pointer_cast<function_tdecl>(decl), ctxt, indent))
      || (write_class_tdecl
      (dynamic_pointer_cast<class_tdecl>(decl), ctxt, indent)))
    return true;

  return false;
}

/// Emit a declaration, along with its scope.
///
/// This function is called at the end of emitting a translation unit,
/// to emit type declarations that were referenced by types that were
/// emitted in the TU already, but that were not emitted themselves.
///
/// @param decl the decl to emit.
///
/// @param ctxt the write context to use.
///
/// @param initial_indent the number of indentation spaces to use.
static void
write_decl_in_scope(const decl_base_sptr&   decl,
            write_context&      ctxt,
            unsigned            initial_indent)
{
  type_base_sptr type = is_type(decl);
  if ((type && ctxt.type_is_emitted(type))
      || (!type && ctxt.decl_is_emitted(decl)))
    return;

  list<scope_decl*> scopes;
  for (scope_decl* s = decl->get_scope();
       s && !is_global_scope(s);
       s = s->get_scope())
    scopes.push_front(s);

  ostream& o = ctxt.get_ostream();
  const config& c = ctxt.get_config();
  stack<string> closing_tags;
  stack<unsigned> closing_indents;
  unsigned indent = initial_indent;
  for (list<scope_decl*>::const_iterator i = scopes.begin();
       i != scopes.end();
       ++i)
    {
      ABG_ASSERT(!is_global_scope(*i));

      // A type scope is either a namespace ...
      if (namespace_decl* n = is_namespace(*i))
    {
      do_indent(o, indent);
      o << "<namespace-decl name='"
        << xml::escape_xml_string(n->get_name())
        << "'>\n";
      closing_tags.push("</namespace-decl>");
      closing_indents.push(indent);
    }
      // ... or a class.
      else if (class_decl* c = is_class_type(*i))
    {
      c = is_class_type(look_through_decl_only_class(c));
      class_decl_sptr class_type(c, noop_deleter());
      bool do_break = false;
      if (!ctxt.type_is_emitted(c))
        {
          write_type(class_type, ctxt, initial_indent);
          // So, we've written class_type, which is a scope of
          // 'decl'.  So normally, decl should have been emitted
          // by the emitting of class_type.
          //
          // But there can be times where 'decl' is not emitted.
          //
          // 'decl' can still be not emitted if the canonical type
          // of class_type (the one that is emitted) is not the
          // variant that contains the member type 'decl'.  In
          // that case, 'decl' still needs to be emitted after
          // emitting tags for its scope.  That is done by the
          // 'if' block below.
          do_break = true;
        }

      if (!do_break
          // if decl/type is still not emitted, then it means the
          // canonical type for 'class_type' above was emitted but
          // wasn't the variant containing the member type
          // 'decl/type'.  In that case, we'll need to emit the
          // tags for the scope of decl and then emit decl.
          || (type && !ctxt.type_is_emitted(type))
          || (!type && !ctxt.decl_is_emitted(decl)))
        {
          write_class_decl_opening_tag(class_type, "", ctxt, indent,
                       /*prepare_to_handle_empty=*/false);
          closing_tags.push("</class-decl>");
          closing_indents.push(indent);

          unsigned nb_ws = get_indent_to_level(ctxt, indent, 1);
          write_member_type_opening_tag(type, ctxt, nb_ws);
          indent = nb_ws;
          closing_tags.push("</member-type>");
          closing_indents.push(nb_ws);
        }

      if (do_break)
        break;
    }
      else if (union_decl *u = is_union_type(*i))
    {
      u = is_union_type(look_through_decl_only(u));
      union_decl_sptr union_type(u, noop_deleter());
      if (!ctxt.type_is_emitted(u))
        {
          write_type(union_type, ctxt, initial_indent);
          break;
        }
      else
        {
          write_union_decl_opening_tag(union_type, "", ctxt, indent,
                       /*prepare_to_handle_empty=*/false);
          closing_tags.push("</union-decl>");
          closing_indents.push(indent);

          unsigned nb_ws = get_indent_to_level(ctxt, indent, 1);
          write_member_type_opening_tag(type, ctxt, nb_ws);
          indent = nb_ws;
          closing_tags.push("</member-type>");
          closing_indents.push(nb_ws);
        }
    }
      else
    // We should never reach this point.
    abort();
      indent += c.get_xml_element_indent();
    }

  bool do_write = false;
  if (type_base_sptr type = is_type(decl))
    {
      if (!ctxt.type_is_emitted(type))
    do_write= true;
    }
  else
    {
      if (!ctxt.decl_is_emitted(decl))
    do_write= true;
    }

  if (do_write)
    write_decl(decl, ctxt, indent);

  while (!closing_tags.empty())
    {
      do_indent(o, closing_indents.top());
      o << closing_tags.top() << "\n";
      closing_tags.pop();
      closing_indents.pop();
    }
}

/// Create a @ref write_context object that can be used to emit abixml
/// files.
///
/// @param env the environment for the @ref write_context object to use.
///
/// @param default_output_stream the default output stream to use.
///
/// @return the new @ref write_context object.
write_context_sptr
create_write_context(const environment& env,
             ostream& default_output_stream)
{
  write_context_sptr ctxt(new write_context(env, default_output_stream));
  return ctxt;
}

/// Set the "show-locs" flag.
///
/// When this flag is set then the XML writer emits location (///
/// information (file name, line and column) for the ABI artifacts
/// that it emits.
///
/// @param ctxt the @ref write_context to set the option for.
///
/// @param flag the new value of the option.
void
set_show_locs(write_context& ctxt, bool flag)
{ctxt.set_show_locs(flag);}

/// Set the 'annotate' flag.
///
/// When this flag is set then the XML writer annotates ABI artifacts
/// with a human readable description.
///
/// @param ctxt the context to set this flag on to.
///
/// @param flag the new value of the 'annotate' flag.
void
set_annotate(write_context& ctxt, bool flag)
{ctxt.set_annotate(flag);}

/// Set the new ostream.
///
/// The ostream refers to the object, writers should stream new output to.
///
/// @param ctxt the context to set this to.
///
/// @param os the new ostream
void
set_ostream(write_context& ctxt, ostream& os)
{ctxt.set_ostream(os);}

/// Set the 'write-architecture' flag.
///
/// When this flag is set then the XML writer will emit architecture
/// information
///
/// @param ctxt the context to set this flag on to.
///
/// @param flag the new value of the 'write-architecture' flag.
void
set_write_architecture(write_context& ctxt, bool flag)
{ctxt.set_write_architecture(flag);}

/// Set the 'write-corpus-path' flag.
///
/// When this flag is set then the XML writer will emit corpus-path
/// information
///
/// @param ctxt the context to set this flag on to.
///
/// @param flag the new value of the 'write-corpus-path' flag.
void
set_write_corpus_path(write_context& ctxt, bool flag)
{ctxt.set_write_corpus_path(flag);}

/// Set the 'write-comp-dir' flag.
///
/// When this flag is set then the XML writer will emit compilation dir
/// information
///
/// @param ctxt the context to set this flag on to.
///
/// @param flag the new value of the 'write-comp-dir' flag.
void
set_write_comp_dir(write_context& ctxt, bool flag)
{ctxt.set_write_comp_dir(flag);}

/// Set the 'short-locs' flag.
///
/// When this flag is set then the XML writer will emit only file names
/// rather than full paths.
///
/// @param ctxt the context to set this flag on to.
///
/// @param flag the new value of the 'short-locs' flag.
void
set_short_locs(write_context& ctxt, bool flag)
{ctxt.set_short_locs(flag);}

/// Set the 'parameter-names' flag.
///
/// When this flag is set then the XML writer will emit the names of
/// function parameters.
///
/// @param ctxt the context to set this flag on to.
///
/// @param flag the new value of the 'parameter-names' flag.
void
set_write_parameter_names(write_context& ctxt, bool flag)
{ctxt.set_write_parameter_names(flag);}

/// Set the 'elf-needed' flag.
///
/// When this flag is set then the XML writer will emit corpus
/// get_needed() (DT_NEEDED) information.
///
/// @param ctxt the context to set this flag on to.
///
/// @param flag the new value of the 'elf-needed' flag.
void
set_write_elf_needed(write_context& ctxt, bool flag)
{ctxt.set_write_elf_needed(flag);}

/// Set the 'undefined-symbols' flag.
///
/// When this flag is set then the XML writer will emit corpus
/// information about the undefined function and variable symbols.
///
/// @param ctxt the context to set this flag on to.
///
/// @param flag the new value of the 'undefined-symbols' flag.
void
set_write_undefined_symbols(write_context& ctxt, bool flag)
{ctxt.set_write_undefined_symbols(flag);}

/// Set the 'default-sizes' flag.
///
/// When this flag is set then the XML writer will emit default
/// size-in-bits attributes for pointer type definitions, reference
/// type definitions, function declarations and function types even
/// when they are equal to the default address size of the translation
/// unit.
///
/// @param ctxt the context to set this flag on to.
///
/// @param flag the new value of the 'default-sizes' flag.
void
set_write_default_sizes(write_context& ctxt, bool flag)
{ctxt.set_write_default_sizes(flag);}

/// Set the 'type-id-style' property.
///
/// This property controls the kind of type ids used in XML output.
///
/// @param ctxt the context to set this property on.
///
/// @param style the new value of the 'type-id-style' property.
void
set_type_id_style(write_context& ctxt, type_id_style_kind style)
{ctxt.set_type_id_style(style);}

/// Serialize the canonical types of a given scope.
///
/// @param scope the scope to consider.
///
/// @param ctxt the write context to use.
///
/// @param indent the number of white space indentation to use.
 //
 // @param is_member_type if true, the canonical types are emitted as
 // member types (of a class).
 //
 // return true upon successful completion.
static bool
write_canonical_types_of_scope(const scope_decl &scope,
                   write_context        &ctxt,
                   const unsigned       indent,
                   bool         is_member_type = false)
{
  const type_base_sptrs_type &canonical_types =
    scope.get_sorted_canonical_types();

  for (type_base_sptrs_type::const_iterator i = canonical_types.begin();
       i != canonical_types.end();
       ++i)
    {
      if (ctxt.type_is_emitted(*i))
    continue;
      if (is_member_type)
    write_member_type(*i, ctxt, indent);
      else
    write_type(*i, ctxt, indent);
    }

  return true;
}

/// Test if a type referenced in a given translation unit should be
/// emitted or not.
///
/// This is a subroutine of @ref write_translation_unit.
///
/// @param t the type to consider.
///
/// @param ctxt the write context to consider.
///
/// @param tu the translation unit to consider.
///
/// @param tu_is_last true if @p tu is the last translation unit being
/// emitted.
///
/// @return true iff @p t is to be emitted.
static bool
referenced_type_should_be_emitted(const type_base *t,
                  const write_context& ctxt,
                  const translation_unit& tu,
                  bool tu_is_last)
{
  if ((tu_is_last || (t->get_translation_unit()
              && (t->get_translation_unit()->get_absolute_path()
              == tu.get_absolute_path())))
      && !ctxt.type_is_emitted(t))
    return true;
  return false;
}

/// Emit the types that were referenced by other emitted types.
///
/// This is a sub-routine of write_translation_unit.
///
/// @param ctxt the write context to use.
///
/// @param tu the current translation unit that is being emitted.
///
/// @param indent the indentation string.
///
/// @param is_last whether @p tu is the last translation unit or not.
static void
write_referenced_types(write_context &      ctxt,
               const translation_unit&  tu,
               const unsigned       indent,
               bool         is_last)
{
  const config& c = ctxt.get_config();
  // Now let's handle types that were referenced, but not yet
  // emitted because they are either:
  //   1/ Types without canonical type
  //   2/ or function types (these might have no scope).

  // So this map of type -> string is to contain the referenced types
  // we need to emit.
  type_ptr_set_type referenced_types_to_emit;

  // For each referenced type, ensure that it is either emitted in the
  // translation unit to which it belongs or in the last translation
  // unit as a last resort.
  for (type_ptr_set_type::const_iterator i =
     ctxt.get_referenced_types().begin();
       i != ctxt.get_referenced_types().end();
       ++i)
    if (referenced_type_should_be_emitted(*i, ctxt, tu, is_last))
      referenced_types_to_emit.insert(*i);

  for (fn_type_ptr_set_type::const_iterator i =
     ctxt.get_referenced_function_types().begin();
       i != ctxt.get_referenced_function_types().end();
       ++i)
    if (referenced_type_should_be_emitted(*i, ctxt, tu, is_last))
      referenced_types_to_emit.insert(*i);

  // Ok, now let's emit the referenced type for good.
  while (!referenced_types_to_emit.empty())
    {
      // But first, we need to sort them, otherwise, emitting the ABI
      // (in xml) of the same binary twice will yield different
      // results, because we'd be walking an *unordered* hash table.
      vector<type_base*> sorted_referenced_types;
      ctxt.sort_types(referenced_types_to_emit,
              sorted_referenced_types);

      // Now, emit the referenced decls in a sorted order.
      for (vector<type_base*>::const_iterator i =
         sorted_referenced_types.begin();
       i != sorted_referenced_types.end();
       ++i)
    {
      // We handle types which have declarations *and* function
      // types here.
      type_base* t = *i;
      if (!ctxt.type_is_emitted(t))
        {
          if (decl_base* d = get_type_declaration(t))
        {
          decl_base_sptr decl(d, noop_deleter());
          write_decl_in_scope(decl, ctxt,
                      indent + c.get_xml_element_indent());
        }
          else if (function_type* f = is_function_type(t))
        {
          function_type_sptr fn_type(f, noop_deleter());
          write_function_type(fn_type, ctxt,
                      indent + c.get_xml_element_indent());
        }
          else
        ABG_ASSERT_NOT_REACHED;
        }
    }

      // So all the (referenced) types that we wanted to emit were
      // emitted.
      referenced_types_to_emit.clear();

      // But then, while emitting those referenced type, other types
      // might have been referenced by those referenced types
      // themselves!  So let's look at the sets of referenced type
      // that are maintained for the entire ABI corpus and see if
      // there are still some referenced types in there that are not
      // emitted yet.  If yes, then we'll emit those again.

      // For each referenced type, ensure that it is either emitted in
      // the translation unit to which it belongs or in the last
      // translation unit as a last resort.
      for (type_ptr_set_type::const_iterator i =
         ctxt.get_referenced_types().begin();
       i != ctxt.get_referenced_types().end();
       ++i)
    if (referenced_type_should_be_emitted(*i, ctxt, tu, is_last))
      referenced_types_to_emit.insert(*i);
    }
}

/// Serialize a translation unit to an output stream.
///
/// @param ctxt the context of the serialization.  It contains e.g,
/// the output stream to serialize to.
///
/// @param tu the translation unit to serialize.
///
/// @param indent how many indentation spaces to use during the
/// serialization.
///
/// @param is_last If true, it means the TU to emit is the last one of
/// the corpus.  If this is the case, all the remaining referenced
/// types that were not emitted are going to be emitted here,
/// irrespective of if they belong to this TU or not.  This is quite a
/// hack.  Ideally, we should have a pass that walks all the TUs,
/// detect their non-emitted referenced types, before hand.  Then,
/// when we start emitting the TUs, we know for each TU which
/// non-emitted referenced type should be emitted.  As we don't yet
/// have such a pass, we do our best for now.
///
/// @return true upon successful completion, false otherwise.
bool
write_translation_unit(write_context&       ctxt,
               const translation_unit&  tu,
               const unsigned       indent,
               bool         is_last)
{
  if (tu.is_empty() && !is_last)
    return false;

  if (is_last
      && tu.is_empty()
      && ctxt.has_non_emitted_referenced_types())
    return false;

  ostream& o = ctxt.get_ostream();
  const config& c = ctxt.get_config();

  do_indent(o, indent);

  o << "<abi-instr";

  if (tu.get_address_size() != 0)
    o << " address-size='" << static_cast<int>(tu.get_address_size()) << "'";

  std::string tu_path = tu.get_path();
  if (ctxt.get_short_locs())
    tools_utils::base_name(tu_path, tu_path);
  if (!tu_path.empty())
    o << " path='" << xml::escape_xml_string(tu_path) << "'";

  if (!tu.get_compilation_dir_path().empty() && ctxt.get_write_comp_dir())
    o << " comp-dir-path='"
      << xml::escape_xml_string(tu.get_compilation_dir_path()) << "'";

  if (tu.get_language() != translation_unit::LANG_UNKNOWN)
    o << " language='"
      << translation_unit_language_to_string(tu.get_language())
      <<"'";

  if (tu.is_empty() && !is_last)
    {
      o << "/>\n";
      return true;
    }

  o << ">\n";

  write_canonical_types_of_scope(*tu.get_global_scope(),
                 ctxt, indent + c.get_xml_element_indent());

  typedef scope_decl::declarations declarations;
  const declarations& decls = tu.get_global_scope()->get_sorted_member_decls();

  for (const decl_base_sptr& decl : decls)
    {
      if (type_base_sptr t = is_type(decl))
    {
      // Emit declaration-only classes that are needed. Some of
      // these classes can be empty.  Those beasts can be classes
      // that only contain member types.  They can also be classes
      // considered "opaque".
      if (class_decl_sptr class_type = is_class_type(t))
        if (class_type->get_is_declaration_only()
        && !ctxt.type_is_emitted(class_type))
          write_type(class_type, ctxt,
             indent + c.get_xml_element_indent());

      if (is_non_canonicalized_type(t) && !ctxt.type_is_emitted(t))
        write_type(t, ctxt, indent + c.get_xml_element_indent());
    }
      else if (is_var_decl(decl))
    {
      if (!ctxt.decl_is_emitted(decl))
        write_decl_in_scope(decl, ctxt, indent + c.get_xml_element_indent());
    }
      else
    {
      if (!ctxt.decl_is_emitted(decl))
        write_decl(decl, ctxt, indent + c.get_xml_element_indent());
    }
    }

  // Write the undefined functions that belong to this translation
  // unit
  if (const abigail::ir::corpus* abi = tu.get_corpus())
    for (auto undefined_function : abi->get_sorted_undefined_functions())
      {
    function_decl_sptr f(const_cast<function_decl*>(undefined_function),
                 noop_deleter());
    if (f->get_translation_unit() != &tu || ctxt.decl_is_emitted(f))
      continue;

    write_decl(f, ctxt, indent + c.get_xml_element_indent());
      }

  // Write the undefined variables that belong to this translation
  // unit
  if (const abigail::ir::corpus* abi = tu.get_corpus())
    for (auto undefined_var : abi->get_sorted_undefined_variables())
      {
    var_decl_sptr v = undefined_var;
    if (v->get_translation_unit() != &tu || ctxt.decl_is_emitted(v))
      continue;

    write_decl(v, ctxt, indent + c.get_xml_element_indent());
      }

  write_referenced_types(ctxt, tu, indent, is_last);

  // Now handle all function types that were not only referenced by
  // emitted types.
  const vector<function_type_sptr>& t = tu.get_live_fn_types();
  vector<type_base_sptr> sorted_types;
  ctxt.sort_types(t, sorted_types);

  for (vector<type_base_sptr>::const_iterator i = sorted_types.begin();
       i != sorted_types.end();
       ++i)
    {
      function_type_sptr fn_type = is_function_type(*i);

      if (fn_type->get_is_artificial() || ctxt.type_is_emitted(fn_type))
    // This function type is either already emitted or it's
    // artificial (i.e, artificially created just to represent the
    // conceptual type of a function), so skip it.
    continue;

      ABG_ASSERT(fn_type);
      write_function_type(fn_type, ctxt, indent + c.get_xml_element_indent());
    }

  // After we've written out the live function types, we need to write
  // the types they referenced.
  write_referenced_types(ctxt, tu, indent, is_last);

  do_indent(o, indent);
  o << "</abi-instr>\n";

  return true;
}

/// Serialize a pointer to an instance of basic type declaration, into
/// an output stream.
///
/// @param d the basic type declaration to serialize.
///
/// @param ctxt the context of the serialization.  It contains e.g, the
/// output stream to serialize to.
///
/// @param indent how many indentation spaces to use during the
/// serialization.
///
/// @return true upon successful completion, false otherwise.
static bool
write_type_decl(const type_decl_sptr& d, write_context& ctxt, unsigned indent)
{
  if (!d)
    return false;

  ostream& o = ctxt.get_ostream();

  annotate(d, ctxt, indent);

  do_indent(o, indent);

  o << "<type-decl name='" << xml::escape_xml_string(d->get_name()) << "'";

  write_common_type_info(d, ctxt);

  o << "/>\n";

  return true;
}

/// Serialize a namespace declaration int an output stream.
///
/// @param decl the namespace declaration to serialize.
///
/// @param ctxt the context of the serialization.  It contains e.g, the
/// output stream to serialize to.
///
/// @param indent how many indentation spaces to use during the
/// serialization.
///
/// @return true upon successful completion, false otherwise.
static bool
write_namespace_decl(const namespace_decl_sptr& decl,
             write_context& ctxt, unsigned indent)
{
  if (!decl || decl->is_empty_or_has_empty_sub_namespaces())
    return false;

  ostream& o = ctxt.get_ostream();
  const config &c = ctxt.get_config();

  annotate(decl, ctxt, indent);

  do_indent(o, indent);

  o << "<namespace-decl name='"
    << xml::escape_xml_string(decl->get_name())
    << "'>\n";

  typedef scope_decl::declarations      declarations;
  typedef declarations::const_iterator const_iterator;
  const declarations& d = decl->get_sorted_member_decls();

  write_canonical_types_of_scope(*decl, ctxt,
                 indent + c.get_xml_element_indent());

  for (const_iterator i = d.begin(); i != d.end(); ++i)
    {
      if (type_base_sptr t = is_type(*i))
    if (ctxt.type_is_emitted(t))
      // This type has already been emitted to the current
      // translation unit so do not emit it again.
      continue;
      write_decl(*i, ctxt, indent + c.get_xml_element_indent());
    }

  do_indent(o, indent);
  o << "</namespace-decl>\n";

  return true;
}

/// Serialize a qualified type declaration to an output stream.
///
/// @param decl the qualfied type declaration to write.
///
/// @param id the type id identitifier to use in the serialized
/// output.  If this is empty, the function will compute an
/// appropriate one.  This is useful when this function is called to
/// serialize the underlying type of a member type; in that case, the
/// caller has already computed the id of the *member type*, and that
/// id is the one to be written as the value of the 'id' attribute of
/// the XML element of the underlying type.
///
/// @param ctxt the write context.
///
/// @param indent the number of space to indent to during the
/// serialization.
///
/// @return true upon successful completion, false otherwise.
static bool
write_qualified_type_def(const qualified_type_def_sptr& decl,
             const string&              id,
             write_context&         ctxt,
             unsigned               indent)
{
  if (!decl)
    return false;

  ostream& o = ctxt.get_ostream();


  type_base_sptr underlying_type = decl->get_underlying_type();

  annotate(decl, ctxt, indent);

  do_indent(o, indent);
  o << "<qualified-type-def type-id='"
    << ctxt.get_id_for_type(underlying_type)
    << "'";

  ctxt.record_type_as_referenced(underlying_type);

  if (decl->get_cv_quals() & qualified_type_def::CV_CONST)
    o << " const='yes'";
  if (decl->get_cv_quals() & qualified_type_def::CV_VOLATILE)
    o << " volatile='yes'";
  if (decl->get_cv_quals() & qualified_type_def::CV_RESTRICT)
    o << " restrict='yes'";

  write_common_type_info(decl, ctxt, id);

  o << "/>\n";

  return true;
}

/// Serialize a qualified type declaration to an output stream.
///
/// @param decl the qualfied type declaration to write.
///
/// @param ctxt the write context.
///
/// @param indent the number of space to indent to during the
/// serialization.
///
/// @return true upon successful completion, false otherwise.
static bool
write_qualified_type_def(const qualified_type_def_sptr& decl,
             write_context&         ctxt,
             unsigned               indent)
{return write_qualified_type_def(decl, "", ctxt, indent);}

/// Serialize a pointer to an instance of pointer_type_def.
///
/// @param decl the pointer_type_def to serialize.
///
/// @param id the type id identitifier to use in the serialized
/// output.  If this is empty, the function will compute an
/// appropriate one.  This is useful when this function is called to
/// serialize the underlying type of a member type; in that case, the
/// caller has already computed the id of the *member type*, and that
/// id is the one to be written as the value of the 'id' attribute of
/// the XML element of the underlying type.
///
/// @param ctxt the context of the serialization.
///
/// @param indent the number of indentation white spaces to use.
///
/// @return true upon succesful completion, false otherwise.
static bool
write_pointer_type_def(const pointer_type_def_sptr& decl,
               const string&            id,
               write_context&           ctxt,
               unsigned         indent)
{
  if (!decl)
    return false;

  ostream& o = ctxt.get_ostream();

  annotate(decl, ctxt, indent);

  do_indent(o, indent);

  string i;

  o << "<pointer-type-def ";

  type_base_sptr pointed_to_type = decl->get_pointed_to_type();

  i = ctxt.get_id_for_type(pointed_to_type);

  o << "type-id='" << i << "'";

  ctxt.record_type_as_referenced(pointed_to_type);

  write_common_type_info(decl, ctxt, id);

  o << "/>\n";

  return true;
}

/// Serialize a pointer to an instance of pointer_type_def.
///
/// @param decl the pointer_type_def to serialize.
///
/// @param ctxt the context of the serialization.
///
/// @param indent the number of indentation white spaces to use.
///
/// @return true upon succesful completion, false otherwise.
static bool
write_pointer_type_def(const pointer_type_def_sptr& decl,
               write_context&           ctxt,
               unsigned         indent)
{return write_pointer_type_def(decl, "", ctxt, indent);}

/// Serialize a pointer to an instance of reference_type_def.
///
/// @param decl the reference_type_def to serialize.
///
/// @param id the type id identitifier to use in the serialized
/// output.  If this is empty, the function will compute an
/// appropriate one.  This is useful when this function is called to
/// serialize the underlying type of a member type; in that case, the
/// caller has already computed the id of the *member type*, and that
/// id is the one to be written as the value of the 'id' attribute of
/// the XML element of the underlying type.
///
/// @param ctxt the context of the serialization.
///
/// @param indent the number of indentation white spaces to use.
///
/// @return true upon succesful completion, false otherwise.
static bool
write_reference_type_def(const reference_type_def_sptr& decl,
             const string&              id,
             write_context&         ctxt,
             unsigned               indent)
{
  if (!decl)
    return false;

  annotate(decl->get_canonical_type(), ctxt, indent);

  ostream& o = ctxt.get_ostream();

  do_indent(o, indent);

  o << "<reference-type-def kind='";
  if (decl->is_lvalue())
    o << "lvalue";
  else
    o << "rvalue";
  o << "'";

  type_base_sptr pointed_to_type = decl->get_pointed_to_type();
  o << " type-id='" << ctxt.get_id_for_type(pointed_to_type) << "'";

  ctxt.record_type_as_referenced(pointed_to_type);

  if (function_type_sptr f = is_function_type(decl->get_pointed_to_type()))
    ctxt.record_type_as_referenced(f);

  write_common_type_info(decl, ctxt, id);

  o << "/>\n";

  return true;
}

/// Serialize a pointer to an instance of reference_type_def.
///
/// @param decl the reference_type_def to serialize.
///
/// @param ctxt the context of the serialization.
///
/// @param indent the number of indentation white spaces to use.
///
/// @return true upon succesful completion, false otherwise.
static bool
write_reference_type_def(const reference_type_def_sptr& decl,
             write_context&         ctxt,
             unsigned               indent)
{return write_reference_type_def(decl, "", ctxt, indent);}

/// Serialize a pointer to an instance of @ref ptr_to_mbr_type.
///
/// @param decl a pointer to the @ref ptr_to_mbr_type to serialize.
///
/// @param id the ID of the type.  If it's an empty string then a new
/// ID is generated.
///
/// @param ctxt the context of the serialization.
///
/// @param indent the number of indentation white spaces to use.
///
/// @return true upon succesful completion, false otherwise.
static bool
write_ptr_to_mbr_type(const ptr_to_mbr_type_sptr& decl,
              const string& id, write_context& ctxt,
              unsigned indent)
{
  if (!decl)
    return false;

  annotate(decl->get_canonical_type(), ctxt, indent);

  ostream& o = ctxt.get_ostream();

  do_indent(o, indent);

  o << "<pointer-to-member-type";

  type_base_sptr member_type = decl->get_member_type();
  string i = ctxt.get_id_for_type(member_type);
  o << " member-type-id='" << i << "'";
  ctxt.record_type_as_referenced(member_type);

  type_base_sptr containing_type = decl->get_containing_type();
  i = ctxt.get_id_for_type(containing_type);
  o << " containing-type-id='" << i << "'";
  ctxt.record_type_as_referenced(containing_type);

  write_common_type_info(decl, ctxt, id);

  o << "/>\n";

  return true;
}

/// Serialize a pointer to an instance of @ref ptr_to_mbr_type.
///
/// @param decl a pointer to the @ref ptr_to_mbr_type to serialize.
///
/// @param ctxt the context of the serialization.
///
/// @param indent the number of indentation white spaces to use.
///
/// @return true upon succesful completion, false otherwise.
static bool
write_ptr_to_mbr_type(const ptr_to_mbr_type_sptr& decl,
              write_context& ctxt, unsigned indent)
{return write_ptr_to_mbr_type(decl, "", ctxt, indent);}

/// Serialize an instance of @ref array_type_def::subrange_type.
///
/// @param decl the array_type_def::subrange_type to serialize.
///
/// @param ctxt the context of the serialization.
///
/// @param indent the number of indentation white spaces to use.
///
/// return true upon successful completion, false otherwise.
static bool
write_array_subrange_type(const array_type_def::subrange_sptr&  decl,
              write_context&            ctxt,
              unsigned              indent)
{
  if (!decl)
    return false;

  annotate(decl, ctxt, indent);

  ostream& o = ctxt.get_ostream();

  do_indent(o, indent);

  o << "<subrange";

  if (!decl->get_name().empty())
    o << " name='" << decl->get_name() << "'";

  o << " length='";
  if (decl->is_non_finite())
    o << "unknown";
  else
    o << decl->get_length();

  o << "'";

  ABG_ASSERT(decl->is_non_finite()
         || decl->get_length() == 0
         || (decl->get_length() ==
         (uint64_t) (decl->get_upper_bound()
                 - decl->get_lower_bound() + 1)));
  o << " lower-bound='" << decl->get_lower_bound() << "' upper-bound='"
    << decl->get_upper_bound() << "'";

  type_base_sptr underlying_type = decl->get_underlying_type();
  if (underlying_type)
    {
      o << " type-id='"
    << ctxt.get_id_for_type(underlying_type)
    << "'";
      ctxt.record_type_as_referenced(underlying_type);
    }

  write_common_type_info(decl, ctxt);

  o << "/>\n";

  return true;
}

/// Serialize a pointer to an instance of array_type_def.
///
/// @param decl the array_type_def to serialize.
///
/// @param id the type id identitifier to use in the serialized
/// output.  If this is empty, the function will compute an
/// appropriate one.  This is useful when this function is called to
/// serialize the underlying type of a member type; in that case, the
/// caller has already computed the id of the *member type*, and that
/// id is the one to be written as the value of the 'id' attribute of
/// the XML element of the underlying type.
///
/// @param ctxt the context of the serialization.
///
/// @param indent the number of indentation white spaces to use.
///
/// @return true upon succesful completion, false otherwise.
static bool
write_array_type_def(const array_type_def_sptr& decl,
             const string&          id,
             write_context&         ctxt,
             unsigned               indent)
{
  if (!decl)
    return false;

  annotate(decl, ctxt, indent);

  ostream& o = ctxt.get_ostream();

  do_indent(o, indent);
  o << "<array-type-def";

  o << " dimensions='" << decl->get_dimension_count() << "'";

  type_base_sptr element_type = decl->get_element_type();
  o << " type-id='" << ctxt.get_id_for_type(element_type) << "'";

  ctxt.record_type_as_referenced(element_type);

  write_common_type_info(decl, ctxt, id);

  if (!decl->get_dimension_count())
    o << "/>\n";
  else
    {
      o << ">\n";

      vector<array_type_def::subrange_sptr>::const_iterator si;

      for (si = decl->get_subranges().begin();
           si != decl->get_subranges().end(); ++si)
        {
      unsigned local_indent =
        indent + ctxt.get_config().get_xml_element_indent();
      write_array_subrange_type(*si, ctxt, local_indent);
    }

      do_indent(o, indent);
      o << "</array-type-def>\n";
    }

  return true;
}

/// Serialize a pointer to an instance of array_type_def.
///
/// @param decl the array_type_def to serialize.
///
/// @param ctxt the context of the serialization.
///
/// @param indent the number of indentation white spaces to use.
///
/// @return true upon succesful completion, false otherwise.
static bool
write_array_type_def(const array_type_def_sptr& decl,
             write_context&     ctxt,
             unsigned           indent)
{return write_array_type_def(decl, "", ctxt, indent);}

/// Serialize a pointer to an instance of enum_type_decl.
///
/// @param decl the enum_type_decl to serialize.
///
/// @param id the type id identitifier to use in the serialized
/// output.  If this is empty, the function will compute an
/// appropriate one.  This is useful when this function is called to
/// serialize the underlying type of a member type; in that case, the
/// caller has already computed the id of the *member type*, and that
/// id is the one to be written as the value of the 'id' attribute of
/// the XML element of the underlying type.
///
/// @param ctxt the context of the serialization.
///
/// @param indent the number of indentation white spaces to use.
///
/// @return true upon succesful completion, false otherwise.
static bool
write_enum_type_decl(const enum_type_decl_sptr& d,
             const string& id,
             write_context& ctxt,
             unsigned indent)
{
  if (!d)
    return false;

  enum_type_decl_sptr decl = is_enum_type(look_through_decl_only_enum(d));

  annotate(decl->get_canonical_type(), ctxt, indent);

  ostream& o = ctxt.get_ostream();

  do_indent(o, indent);
  o << "<enum-decl name='" << xml::escape_xml_string(decl->get_name()) << "'";

  write_naming_typedef(decl, ctxt);
  write_is_artificial(decl, o);
  write_is_non_reachable(is_type(decl), o);

  if (!decl->get_linkage_name().empty())
    o << " linkage-name='"
      << xml::escape_xml_string(decl->get_linkage_name())
      << "'";

  write_common_type_info(decl, ctxt, id);

  o << ">\n";

  do_indent(o, indent + ctxt.get_config().get_xml_element_indent());
  o << "<underlying-type type-id='"
    << ctxt.get_id_for_type(decl->get_underlying_type())
    << "'/>\n";

  for (enum_type_decl::enumerators::const_iterator i =
     decl->get_enumerators().begin();
       i != decl->get_enumerators().end();
       ++i)
    {
      do_indent(o, indent + ctxt.get_config().get_xml_element_indent());
      o << "<enumerator name='"
    << i->get_name()
    << "' value='"
    << i->get_value()
    << "'/>\n";
    }

  do_indent(o, indent);
  o << "</enum-decl>\n";

  return true;
}

/// Serialize a pointer to an instance of enum_type_decl.
///
/// @param decl the enum_type_decl to serialize.
///
/// @param ctxt the context of the serialization.
///
/// @param indent the number of indentation white spaces to use.
///
/// @return true upon succesful completion, false otherwise.
static bool
write_enum_type_decl(const enum_type_decl_sptr& decl,
             write_context&     ctxt,
             unsigned           indent)
{return write_enum_type_decl(decl, "", ctxt, indent);}

/// Serialize an @ref elf_symbol to an XML element of name
/// 'elf-symbol'.
///
/// @param sym the elf symbol to serialize.
///
/// @param ctxt the read context to use.
///
/// @param indent the number of white spaces to use as indentation.
///
/// @return true iff the function completed successfully.
static bool
write_elf_symbol(const elf_symbol_sptr& sym,
         write_context&     ctxt,
         unsigned           indent)
{
  if (!sym)
    return false;

  ostream &o = ctxt.get_ostream();

  annotate(sym, ctxt, indent);
  do_indent(o, indent);
  o << "<elf-symbol name='" << xml::escape_xml_string(sym->get_name()) << "'";
  if (sym->is_variable() && sym->get_size())
  o << " size='" << sym->get_size() << "'";

  if (!sym->get_version().is_empty())
    {
      o << " version='" << sym->get_version().str() << "'";
      o << " is-default-version='";
      if (sym->get_version().is_default())
    o <<  "yes";
      else
    o << "no";
      o << "'";
    }

  write_elf_symbol_type(sym->get_type(), o);

  write_elf_symbol_binding(sym->get_binding(), o);

  write_elf_symbol_visibility(sym->get_visibility(), o);

  write_elf_symbol_aliases(*sym, o);

  o << " is-defined='";
  if (sym->is_defined())
    o << "yes";
  else
    o << "no";
  o << "'";

  if (sym->is_common_symbol())
    o << " is-common='yes'";

  if (sym->get_crc().has_value())
    o << " crc='"
      << std::hex << std::showbase << sym->get_crc().value()
      << std::dec << std::noshowbase << "'";

  if (sym->get_namespace().has_value())
    o << " namespace='" << sym->get_namespace().value() << "'";

  o << "/>\n";

  return true;
}

/// Write the elf symbol database to the output associated to the
/// current context.
///
/// @param syms the sorted elf symbol data to write out.
///
/// @param ctxt the context to consider.
///
/// @param indent the number of white spaces to use as indentation.
///
/// @return true upon successful completion.
static bool
write_elf_symbols_table(const elf_symbols&  syms,
            write_context&      ctxt,
            unsigned        indent)
{
  if (syms.empty())
    return false;

  for (elf_symbols::const_iterator it = syms.begin(); it != syms.end(); ++it)
    write_elf_symbol(*it, ctxt, indent);

  return true;
}

/// Write a vector of dependency names for the current corpus we are
/// writting.
///
/// @param needed the vector of dependency names to write.
///
/// @param ctxt the write context to use for the writting.
///
/// @param indent the number of indendation spaces to use.
///
/// @return true upon successful completion, false otherwise.
static bool
write_elf_needed(const vector<string>&  needed,
         write_context& ctxt,
         unsigned       indent)
{
  if (needed.empty())
    return false;

  ostream& o = ctxt.get_ostream();

  for (vector<string>::const_iterator i = needed.begin();
       i != needed.end();
       ++i)
    {
      do_indent(o, indent);
      o << "<dependency name='" << *i << "'/>\n";
    }
  return true;
}

/// Serialize a pointer to an instance of typedef_decl.
///
/// @param decl the typedef_decl to serialize.
///
/// @param id the type id identitifier to use in the serialized
/// output.  If this is empty, the function will compute an
/// appropriate one.  This is useful when this function is called to
/// serialize the underlying type of a member type; in that case, the
/// caller has already computed the id of the *member type*, and that
/// id is the one to be written as the value of the 'id' attribute of
/// the XML element of the underlying type.
///
/// @param ctxt the context of the serialization.
///
/// @param indent the number of indentation white spaces to use.
///
/// @return true upon succesful completion, false otherwise.
static bool
write_typedef_decl(const typedef_decl_sptr& decl,
           const string&        id,
           write_context&       ctxt,
           unsigned         indent)
{
  if (!decl)
    return false;

  ostream &o = ctxt.get_ostream();

  annotate(decl, ctxt, indent);

  do_indent(o, indent);

  o << "<typedef-decl name='"
    << xml::escape_xml_string(decl->get_name())
    << "'";

  type_base_sptr underlying_type = decl->get_underlying_type();
  string type_id = ctxt.get_id_for_type(underlying_type);
  o << " type-id='" <<  type_id << "'";
  ctxt.record_type_as_referenced(underlying_type);

  write_common_type_info(decl, ctxt, id);

  o << "/>\n";

  return true;
}

/// Serialize a pointer to an instance of typedef_decl.
///
/// @param decl the typedef_decl to serialize.
///
/// @param ctxt the context of the serialization.
///
/// @param indent the number of indentation white spaces to use.
///
/// @return true upon succesful completion, false otherwise.
static bool
write_typedef_decl(const typedef_decl_sptr& decl,
           write_context&       ctxt,
           unsigned         indent)
{return write_typedef_decl(decl, "", ctxt, indent);}

/// Serialize a pointer to an instances of var_decl.
///
/// @param decl the var_decl to serialize.
///
/// @param ctxt the context of the serialization.
///
/// @param write_linkage_name if true, serialize the mangled name of
/// this variable.
///
/// @param indent the number of indentation white spaces to use.
///
/// @return true upon succesful completion, false otherwise.
static bool
write_var_decl(const var_decl_sptr& decl, write_context& ctxt,
           bool write_linkage_name, unsigned indent)
{
  if (!decl)
    return false;

  annotate(decl, ctxt, indent);

  ostream &o = ctxt.get_ostream();

  do_indent(o, indent);

  o << "<var-decl name='" << xml::escape_xml_string(decl->get_name()) << "'";
  type_base_sptr var_type = decl->get_type();
  o << " type-id='" << ctxt.get_id_for_type(var_type) << "'";
  ctxt.record_type_as_referenced(var_type);

  if (write_linkage_name)
    {
      const string& linkage_name = decl->get_linkage_name();
      if (!linkage_name.empty())
    o << " mangled-name='" << linkage_name << "'";
    }

  write_visibility(decl, o);

  write_binding(decl, o);

  write_location(decl, ctxt);

  if (elf_symbol_sptr sym = decl->get_symbol())
    if (corpus* abi = decl->get_corpus())
      write_elf_symbol_reference(ctxt, decl->get_symbol(), *abi, o);

  o << "/>\n";

  ctxt.record_decl_as_emitted(decl);

  return true;
}

/// Write the parameters and return part of the ABIXML description of
/// a function_type.
///
/// @param fun_type the function type to consider.
///
/// @param skip_first_parm if true, the function skips the first
/// parameter of the function type.  This is useful for emitting
/// parameters of method_type IR nodes.
///
/// @param ctxt the write context to use.
///
/// @param indent the number of indentation spaces to use.
static void
write_fn_parm_and_return_types(const function_type_sptr& fun_type,
                   bool skip_first_parm,
                   write_context& ctxt,
                   unsigned indent)
{
  function_type_sptr t =
    fun_type->get_canonical_type()
    ? is_function_type(fun_type->get_canonical_type())
    : fun_type;

  unsigned cur_indent =
    indent + ctxt.get_config().get_xml_element_indent();

  ostream &o = ctxt.get_ostream();

  type_base_sptr parm_type;
  auto pi = t->get_parameters().begin();
  for ((skip_first_parm && pi != t->get_parameters().end()) ? ++pi: pi;
       pi != t->get_parameters().end();
       ++pi)
    {
      if ((*pi)->get_variadic_marker())
        {
          do_indent(o, cur_indent);
          o << "<parameter is-variadic='yes'";
        }
      else
    {
      parm_type = (*pi)->get_type();

          annotate(*pi, ctxt, cur_indent);
          do_indent(o, cur_indent);

      o << "<parameter type-id='"
        << ctxt.get_id_for_type(parm_type)
        << "'";
      ctxt.record_type_as_referenced(parm_type);

      if (ctxt.get_write_parameter_names() && !(*pi)->get_name().empty())
        o << " name='" << xml::escape_xml_string((*pi)->get_name()) << "'";
    }
      write_is_artificial(*pi, o);
      write_location((*pi)->get_location(), ctxt);
      o << "/>\n";
    }

  if (shared_ptr<type_base> return_type = t->get_return_type())
    {
      annotate(return_type , ctxt, cur_indent);
      do_indent(o, cur_indent);
      o << "<return type-id='"
    << ctxt.get_id_for_type(return_type)
    << "'/>\n";
      ctxt.record_type_as_referenced(return_type);
    }
}

/// Serialize a pointer to a function_decl.
///
/// @param decl the pointer to function_decl to serialize.
///
/// @param ctxt the context of the serialization.
///
/// @param skip_first_parm if true, do not serialize the first
/// parameter of the function decl.
///
/// @param indent the number of indentation white spaces to use.
///
/// @return true upon succesful completion, false otherwise.
static bool
write_function_decl(const function_decl_sptr& decl, write_context& ctxt,
            bool skip_first_parm, unsigned indent)
{
  if (!decl)
    return false;

  annotate(decl, ctxt, indent);

  ostream &o = ctxt.get_ostream();

  do_indent(o, indent);

  o << "<function-decl name='"
    << xml::escape_xml_string(decl->get_name())
    << "'";

  if (!decl->get_linkage_name().empty())
    o << " mangled-name='"
      << xml::escape_xml_string(decl->get_linkage_name()) << "'";

  write_location(decl, ctxt);

  if (decl->is_declared_inline())
    o << " declared-inline='yes'";

  write_visibility(decl, o);

  write_binding(decl, o);

  write_size_and_alignment(decl->get_type(), o,
               (ctxt.get_write_default_sizes()
                ? 0
                : decl->get_translation_unit()->get_address_size()),
               0);
  if (elf_symbol_sptr sym = decl->get_symbol())
    if (corpus* abi = decl->get_corpus())
      write_elf_symbol_reference(ctxt, decl->get_symbol(), *abi, o);

  write_type_hash_and_cti(decl->get_type(), o);

  o << ">\n";

  write_fn_parm_and_return_types(decl->get_type(),
                 skip_first_parm,
                 ctxt, indent);

  do_indent(o, indent);
  o << "</function-decl>\n";

  ctxt.record_decl_as_emitted(decl);

  return true;
}

/// Serialize a function_type.
///
/// @param fun_type the pointer to function_type to serialize.
///
/// @param ctxt the context of the serialization.
///
/// @param indent the number of indentation white spaces to use.
///
/// @return true upon succesful completion, false otherwise.
static bool
write_function_type(const function_type_sptr& fun_type,
            write_context& ctxt, unsigned indent)
{
  if (!fun_type)
    return false;

  ABG_ASSERT(fun_type->get_canonical_type()
         || is_non_canonicalized_type(fun_type));

  function_type_sptr fn_type =
    fun_type->get_canonical_type()
    ? is_function_type(fun_type->get_canonical_type())
    : fun_type;

  ostream &o = ctxt.get_ostream();

  annotate(fn_type, ctxt, indent);

  do_indent(o, indent);

  o << "<function-type";


  if (method_type_sptr method_type = is_method_type(fn_type))
    {
      o << " method-class-id='"
    << ctxt.get_id_for_type(method_type->get_class_type())
    << "'";

      write_cdtor_const_static(/*is_ctor=*/false, /*is_dtor=*/false,
                   /*is_const=*/method_type->get_is_const(),
                   /*is_static=*/false, o);
    }

  write_common_type_info(fn_type, ctxt);

  o << ">\n";

  write_fn_parm_and_return_types(fn_type, /*skip_first_parm=*/false,
                 ctxt, indent);

  do_indent(o, indent);

  o << "</function-type>\n";

  return true;
}

/// Write the opening tag of a 'class-decl' element.
///
/// @param decl the class declaration to serialize.
///
/// @param the type ID to use for the 'class-decl' element,, or empty
/// if we need to build a new one.
///
/// @param ctxt the write context to use.
///
/// @param indent the number of white space to use for indentation.
///
/// @param prepare_to_handle_empty if set to true, then this function
/// figures out if the opening tag should be for an empty element or
/// not.  If set to false, then the opening tag is unconditionnaly for
/// a non-empty element.
///
/// @return true upon successful completion.
static bool
write_class_decl_opening_tag(const class_decl_sptr& decl,
                 const string&      id,
                 write_context&     ctxt,
                 unsigned           indent,
                 bool           prepare_to_handle_empty)
{
  if (!decl)
    return false;

  ostream& o = ctxt.get_ostream();

  do_indent_to_level(ctxt, indent, 0);

  o << "<class-decl name='" << xml::escape_xml_string(decl->get_name()) << "'";

  write_is_struct(decl, o);

  write_is_artificial(decl, o);

  write_is_non_reachable(is_type(decl), o);

  write_naming_typedef(decl, ctxt);

  write_visibility(decl, o);

  if (decl->get_earlier_declaration())
    {
      // This instance is the definition of an earlier declaration.
      o << " def-of-decl-id='"
    << ctxt.get_id_for_type(is_type(decl->get_earlier_declaration()))
    << "'";
    }

  write_common_type_info(decl, ctxt, id);

  if (prepare_to_handle_empty && decl->has_no_base_nor_member())
    o << "/>\n";
  else
    o << ">\n";

  return true;
}

/// Write the opening tag of a 'union-decl' element.
///
/// @param decl the union declaration to serialize.
///
/// @param the type ID to use for the 'union-decl' element, or empty
/// if we need to build a new one.
///
/// @param ctxt the write context to use.
///
/// @param indent the number of white space to use for indentation.
///
/// @param prepare_to_handle_empty if set to true, then this function
/// figures out if the opening tag should be for an empty element or
/// not.  If set to false, then the opening tag is unconditionnaly for
/// a non-empty element.
///
/// @return true upon successful completion.
static bool
write_union_decl_opening_tag(const union_decl_sptr& decl,
                 const string&      id,
                 write_context&     ctxt,
                 unsigned           indent,
                 bool           prepare_to_handle_empty)
{
  if (!decl)
    return false;

  ostream& o = ctxt.get_ostream();

  do_indent_to_level(ctxt, indent, 0);

  o << "<union-decl name='" << xml::escape_xml_string(decl->get_name()) << "'";

  write_naming_typedef(decl, ctxt);

  write_visibility(decl, o);

  write_is_artificial(decl, o);

  write_is_non_reachable(is_type(decl), o);

  write_common_type_info(decl, ctxt, id);

  if (prepare_to_handle_empty && decl->has_no_member())
    o << "/>\n";
  else
    o << ">\n";

  return true;
}

/// Serialize a class_decl type.
///
/// @param d the pointer to class_decl to serialize.
///
/// @param id the type id identitifier to use in the serialized
/// output.  If this is empty, the function will compute an
/// appropriate one.  This is useful when this function is called to
/// serialize the underlying type of a member type; in that case, the
/// caller has already computed the id of the *member type*, and that
/// id is the one to be written as the value of the 'id' attribute of
/// the XML element of the underlying type.
///
/// @param ctxt the context of the serialization.
///
/// @param indent the initial indentation to use.
static bool
write_class_decl(const class_decl_sptr& d,
         const string&      id,
         write_context& ctxt,
         unsigned       indent)
{
  if (!d)
    return false;

  class_decl_sptr decl = is_class_type(look_through_decl_only_class(d));

  annotate(decl, ctxt, indent);

  ostream& o = ctxt.get_ostream();

  if (decl->get_is_declaration_only())
    {
      type_base_wptrs_type result;
      canonical_type_sptr_set_type member_types;
      const environment& env = ctxt.get_environment();

      // We are looking at a decl-only class.  All decl-only classes
      // of a given name are equal.  But then the problem is that a
      // decl-only class can still have member types.  So we might
      // have other decl-only classes of the same name as this one,
      // but that have been defined in a namespace definition
      // somewhere else in a different translation-unit, for exemple.
      // Those other decl-only classes of the same name might have a
      // number of different member-types.  So depending on the
      // decl-only class that is seen first, "different" ones might be
      // emitted here, even though they compare equal from the
      // library's point of view.  This might lead to an instability
      // of the abixml output.
      //
      // So let's gather all the member-types of all the decl-only
      // classes of the fully-qualified name and emit them here.
      if (lookup_decl_only_class_types(env.intern(decl->get_qualified_name()),
                       *decl->get_corpus(),
                       result))
    {
      for (auto t : result)
        {
          type_base_sptr type(t);
          class_decl_sptr c = is_class_type(type);
          for (auto m : c->get_member_types())
        if (member_types.find(m) != member_types.end())
          member_types.insert(m);
        }
    }

      if (!member_types.empty())
    {
      // So we now have a hand on the member types of the current
      // decl-only class we are looking at, so let's emit them in
      // a sorted manner.

      write_class_decl_opening_tag(decl, id, ctxt, indent,
                       /*prepare_to_handle_empty=*/
                       member_types.empty());

      vector<type_base_sptr> sorted_types;
      sort_types(member_types, sorted_types);

      unsigned nb_ws = get_indent_to_level(ctxt, indent, 1);
      // Really emit the member types now.
      for (auto t : sorted_types)
        if (!ctxt.type_is_emitted(t))
          write_member_type(t, ctxt, nb_ws);

      if (!member_types.empty())
        o << indent << "</class-decl>\n";

      // Mark all the decl-only classes as emitted, even if just
      // marking one of them should be enough.  We are doing this
      // for logical consistency.
      for (auto t : result)
        ctxt.record_type_as_emitted(type_base_sptr(t));
      return true;
    }
    }

  write_class_decl_opening_tag(decl, id, ctxt, indent,
                   /*prepare_to_handle_empty=*/true);

  if (!decl->has_no_base_nor_member())
    {
      unsigned nb_ws = get_indent_to_level(ctxt, indent, 1);
      type_base_sptr base_type;
      for (class_decl::base_specs::const_iterator base =
         decl->get_base_specifiers().begin();
       base != decl->get_base_specifiers().end();
       ++base)
    {
      annotate((*base)->get_base_class(), ctxt, nb_ws);
      do_indent(o, nb_ws);
      o << "<base-class";

      write_access((*base)->get_access_specifier(), o);

      write_layout_offset (*base, o);

      if ((*base)->get_is_virtual ())
        o << " is-virtual='yes'";

      base_type = (*base)->get_base_class();
      o << " type-id='"
        << ctxt.get_id_for_type(base_type)
        << "'/>\n";

      ctxt.record_type_as_referenced(base_type);
    }

      write_canonical_types_of_scope(*decl, ctxt, nb_ws,
                     /*is_member_type=*/true);

      for (class_decl::member_types::const_iterator ti =
         decl->get_sorted_member_types().begin();
       ti != decl->get_sorted_member_types().end();
       ++ti)
    if (!(*ti)->get_naked_canonical_type())
      write_member_type(*ti, ctxt, nb_ws);

      // Write static data members
      for (const auto& s_dm : decl->get_static_data_members())
    {
      do_indent(o, nb_ws);
      o << "<data-member";
      write_access(get_member_access_specifier(s_dm), o);

      bool is_static = get_member_is_static(s_dm);
      ABG_ASSERT(is_static);
      write_cdtor_const_static(/*is_ctor=*/false,
                   /*is_dtor=*/false,
                   /*is_const=*/false,
                   /*is_static=*/is_static,
                   o);
      write_layout_offset(s_dm, o);
      o << ">\n";

      write_var_decl(s_dm, ctxt, is_static,
             get_indent_to_level(ctxt, indent, 2));

      do_indent_to_level(ctxt, indent, 1);
      o << "</data-member>\n";
    }

      // Write non-static data members
      for (const auto& dm : decl->get_non_static_data_members())
    {
      do_indent(o, nb_ws);
      o << "<data-member";
      write_access(get_member_access_specifier(dm), o);

      bool is_static = get_member_is_static(dm);
      write_cdtor_const_static(/*is_ctor=*/false,
                   /*is_dtor=*/false,
                   /*is_const=*/false,
                   /*is_static=*/is_static,
                   o);
      write_layout_offset(dm, o);
      o << ">\n";

      write_var_decl(dm, ctxt, is_static,
             get_indent_to_level(ctxt, indent, 2));

      do_indent_to_level(ctxt, indent, 1);
      o << "</data-member>\n";
    }

      for (class_decl::member_functions::const_iterator f =
         decl->get_member_functions().begin();
       f != decl->get_member_functions().end();
       ++f)
    {
      function_decl_sptr fn = *f;
      if (get_member_function_is_virtual(fn))
        // All virtual member functions are emitted together,
        // later.
        continue;

      ABG_ASSERT(!get_member_function_is_virtual(fn));

      do_indent(o, nb_ws);
      o << "<member-function";
      write_access(get_member_access_specifier(fn), o);
      write_cdtor_const_static( get_member_function_is_ctor(fn),
                    get_member_function_is_dtor(fn),
                    get_member_function_is_const(fn),
                    get_member_is_static(fn),
                    o);
      o << ">\n";

      write_function_decl(fn, ctxt,
                  /*skip_first_parameter=*/false,
                  get_indent_to_level(ctxt, indent, 2));

      do_indent_to_level(ctxt, indent, 1);
      o << "</member-function>\n";
    }

      for (class_decl::member_functions::const_iterator f =
         decl->get_virtual_mem_fns().begin();
       f != decl->get_virtual_mem_fns().end();
       ++f)
    {
      function_decl_sptr fn = *f;

      ABG_ASSERT(get_member_function_is_virtual(fn));

      do_indent(o, nb_ws);
      o << "<member-function";
      write_access(get_member_access_specifier(fn), o);
      write_cdtor_const_static( get_member_function_is_ctor(fn),
                    get_member_function_is_dtor(fn),
                    get_member_function_is_const(fn),
                    get_member_is_static(fn),
                    o);
      write_voffset(fn, o);
      o << ">\n";

      write_function_decl(fn, ctxt,
                  /*skip_first_parameter=*/false,
                  get_indent_to_level(ctxt, indent, 2));

      do_indent_to_level(ctxt, indent, 1);
      o << "</member-function>\n";
    }

      for (member_function_templates::const_iterator fn =
         decl->get_member_function_templates().begin();
       fn != decl->get_member_function_templates().end();
       ++fn)
    {
      do_indent(o, nb_ws);
      o << "<member-template";
      write_access((*fn)->get_access_specifier(), o);
      write_cdtor_const_static((*fn)->is_constructor(),
                   /*is_dtor=*/false,
                   (*fn)->is_const(),
                   (*fn)->get_is_static(), o);
      o << ">\n";
      write_function_tdecl((*fn)->as_function_tdecl(), ctxt,
                   get_indent_to_level(ctxt, indent, 2));
      do_indent(o, nb_ws);
      o << "</member-template>\n";
    }

      for (member_class_templates::const_iterator cl =
         decl->get_member_class_templates().begin();
       cl != decl->get_member_class_templates().end();
       ++cl)
    {
      do_indent(o, nb_ws);
      o << "<member-template";
      write_access((*cl)->get_access_specifier(), o);
      write_cdtor_const_static(false, false, false,
                   (*cl)->get_is_static(), o);
      o << ">\n";
      write_class_tdecl((*cl)->as_class_tdecl(), ctxt,
                get_indent_to_level(ctxt, indent, 2));
      do_indent(o, nb_ws);
      o << "</member-template>\n";
    }

      do_indent_to_level(ctxt, indent, 0);

      o << "</class-decl>\n";
    }

  ctxt.record_type_as_emitted(decl);

  return true;
}

/// Serialize a class_decl type.
///
/// @param decl the pointer to class_decl to serialize.
///
/// @param ctxt the context of the serialization.
///
/// @param indent the initial indentation to use.
///
/// @return true upon successful completion.
static bool
write_class_decl(const class_decl_sptr& decl,
         write_context& ctxt,
         unsigned       indent)
{return write_class_decl(decl, "", ctxt, indent);}

/// Serialize a @ref union_decl type.
///
/// @param d the pointer to @ref union_decl to serialize.
///
/// @param ctxt the context of the serialization.
///
/// @param indent the initial indentation to use.
///
/// @return true upon successful completion.
static bool
write_union_decl(const union_decl_sptr& d,
         const string& id,
         write_context& ctxt,
         unsigned indent)
{
  if (!d)
    return false;

  union_decl_sptr decl = is_union_type(look_through_decl_only_class(d));

  annotate(decl, ctxt, indent);

  ostream& o = ctxt.get_ostream();

  write_union_decl_opening_tag(decl, id, ctxt, indent,
                   /*prepare_to_handle_empty=*/true);
  if (!decl->has_no_member())
    {
      unsigned nb_ws = get_indent_to_level(ctxt, indent, 1);
      for (class_decl::member_types::const_iterator ti =
         decl->get_member_types().begin();
       ti != decl->get_member_types().end();
       ++ti)
    if (!(*ti)->get_naked_canonical_type())
      write_member_type(*ti, ctxt, nb_ws);

      write_canonical_types_of_scope(*decl, ctxt, nb_ws,
                     /*is_member_type=*/true);

      for (union_decl::data_members::const_iterator data =
         decl->get_data_members().begin();
       data != decl->get_data_members().end();
       ++data)
    {
      do_indent(o, nb_ws);
      o << "<data-member";
      write_access(get_member_access_specifier(*data), o);

      bool is_static = get_member_is_static(*data);
      write_cdtor_const_static(/*is_ctor=*/false,
                   /*is_dtor=*/false,
                   /*is_const=*/false,
                   /*is_static=*/is_static,
                   o);
      o << ">\n";

      write_var_decl(*data, ctxt, is_static,
             get_indent_to_level(ctxt, indent, 2));

      do_indent_to_level(ctxt, indent, 1);
      o << "</data-member>\n";
    }

      for (union_decl::member_functions::const_iterator f =
         decl->get_member_functions().begin();
       f != decl->get_member_functions().end();
       ++f)
    {
      function_decl_sptr fn = *f;
      if (get_member_function_is_virtual(fn))
        // All virtual member functions are emitted together,
        // later.
        continue;

      ABG_ASSERT(!get_member_function_is_virtual(fn));

      do_indent(o, nb_ws);
      o << "<member-function";
      write_access(get_member_access_specifier(fn), o);
      write_cdtor_const_static( get_member_function_is_ctor(fn),
                    get_member_function_is_dtor(fn),
                    get_member_function_is_const(fn),
                    get_member_is_static(fn),
                    o);
      o << ">\n";

      write_function_decl(fn, ctxt,
                  /*skip_first_parameter=*/false,
                  get_indent_to_level(ctxt, indent, 2));

      do_indent_to_level(ctxt, indent, 1);
      o << "</member-function>\n";
    }

      for (member_function_templates::const_iterator fn =
         decl->get_member_function_templates().begin();
       fn != decl->get_member_function_templates().end();
       ++fn)
    {
      do_indent(o, nb_ws);
      o << "<member-template";
      write_access((*fn)->get_access_specifier(), o);
      write_cdtor_const_static((*fn)->is_constructor(),
                   /*is_dtor=*/false,
                   (*fn)->is_const(),
                   (*fn)->get_is_static(), o);
      o << ">\n";
      write_function_tdecl((*fn)->as_function_tdecl(), ctxt,
                   get_indent_to_level(ctxt, indent, 2));
      do_indent(o, nb_ws);
      o << "</member-template>\n";
    }

      for (member_class_templates::const_iterator cl =
         decl->get_member_class_templates().begin();
       cl != decl->get_member_class_templates().end();
       ++cl)
    {
      do_indent(o, nb_ws);
      o << "<member-template";
      write_access((*cl)->get_access_specifier(), o);
      write_cdtor_const_static(false, false, false,
                   (*cl)->get_is_static(), o);
      o << ">\n";
      write_class_tdecl((*cl)->as_class_tdecl(), ctxt,
                get_indent_to_level(ctxt, indent, 2));
      do_indent(o, nb_ws);
      o << "</member-template>\n";
    }

      do_indent_to_level(ctxt, indent, 0);

      o << "</union-decl>\n";
    }

  return true;
}

static bool
write_union_decl(const union_decl_sptr& decl,
         write_context& ctxt,
         unsigned indent)
{return write_union_decl(decl, "", ctxt, indent);}

/// Write the opening tag for a 'member-type' element.
///
/// @param t the member type to consider.
///
/// @param ctxt the write context to use.
///
/// @param indent the number of white spaces to use for indentation.
///
/// @return true upon successful completion.
static bool
write_member_type_opening_tag(const type_base_sptr& t,
                  write_context& ctxt,
                  unsigned indent)
{
  ostream& o = ctxt.get_ostream();

  do_indent_to_level(ctxt, indent, 0);

  decl_base_sptr decl = get_type_declaration(t);
  ABG_ASSERT(decl);

  o << "<member-type";
  write_access(decl, o);
  o << ">\n";

  return true;
}

/// Serialize a member type.
///
/// Note that the id written as the value of the 'id' attribute of the
/// underlying type is actually the id of the member type, not the one
/// for the underying type.  That id takes in account, the access
/// specifier and the qualified name of the member type.
///
/// @param decl the declaration of the member type to serialize.
///
/// @param ctxt the write context to use.
///
/// @param indent the number of levels to use for indentation
static bool
write_member_type(const type_base_sptr& t, write_context& ctxt, unsigned indent)
{
  if (!t)
    return false;

  ostream& o = ctxt.get_ostream();

  write_member_type_opening_tag(t, ctxt, indent);

  string id = ctxt.get_id_for_type(t);

  unsigned nb_ws = get_indent_to_level(ctxt, indent, 1);
  ABG_ASSERT(write_qualified_type_def(dynamic_pointer_cast<qualified_type_def>(t),
                      id, ctxt, nb_ws)
         || write_pointer_type_def(dynamic_pointer_cast<pointer_type_def>(t),
                   id, ctxt, nb_ws)
         || write_reference_type_def(dynamic_pointer_cast<reference_type_def>(t),
                     id, ctxt, nb_ws)
         || write_ptr_to_mbr_type(dynamic_pointer_cast<ptr_to_mbr_type>(t),
                      id, ctxt, nb_ws)
         || write_array_type_def(dynamic_pointer_cast<array_type_def>(t),
                     id, ctxt, nb_ws)
         || write_enum_type_decl(dynamic_pointer_cast<enum_type_decl>(t),
                     id, ctxt, nb_ws)
         || write_typedef_decl(dynamic_pointer_cast<typedef_decl>(t),
                   id, ctxt, nb_ws)
         || write_union_decl(dynamic_pointer_cast<union_decl>(t),
                 id, ctxt, nb_ws)
         || write_class_decl(dynamic_pointer_cast<class_decl>(t),
                 id, ctxt, nb_ws));

  do_indent_to_level(ctxt, indent, 0);
  o << "</member-type>\n";

  return true;
}

/// Serialize an instance of type_tparameter.
///
/// @param decl the instance to serialize.
///
/// @param ctxt the context of the serialization.
///
/// @param indent the initial indentation to use.
///
/// @return true upon successful completion, false otherwise.
static bool
write_type_tparameter(const type_tparameter_sptr    decl,
              write_context&            ctxt,
              unsigned              indent)
{
  if (!decl)
    return false;

  ostream &o = ctxt.get_ostream();
  do_indent_to_level(ctxt, indent, 0);

  string id_attr_name;
  if (ctxt.type_has_existing_id(decl))
    id_attr_name = "type-id";
  else
    id_attr_name = "id";

  o << "<template-type-parameter "
    << id_attr_name << "='" <<  ctxt.get_id_for_type(decl) << "'";

  std::string name = xml::escape_xml_string(decl->get_name ());
  if (!name.empty())
    o << " name='" << name << "'";

  write_location(decl, ctxt);

  o << "/>\n";

  ctxt.record_type_as_emitted(decl);

  return true;
}

/// Serialize an instance of non_type_tparameter.
///
/// @param decl the instance to serialize.
///
/// @param ctxt the context of the serialization.
///
/// @param indent the intial indentation to use.
///
/// @return true open successful completion, false otherwise.
static bool
write_non_type_tparameter(
 const shared_ptr<non_type_tparameter>  decl,
 write_context& ctxt, unsigned indent)
{
  if (!decl)
    return false;

  ostream &o = ctxt.get_ostream();
  do_indent_to_level(ctxt, indent, 0);

  o << "<template-non-type-parameter type-id='"
    << ctxt.get_id_for_type(decl->get_type())
    << "'";

  string name = xml::escape_xml_string(decl->get_name());
  if (!name.empty())
    o << " name='" << name << "'";

  write_location(decl, ctxt);

  o << "/>\n";

  return true;
}

/// Serialize an instance of template template parameter.
///
/// @param decl the instance to serialize.
///
/// @param ctxt the context of the serialization.
///
/// @param indent the initial indentation to use.
///
/// @return true upon successful completion, false otherwise.

static bool
write_template_tparameter (const template_tparameter_sptr   decl,
               write_context&           ctxt,
               unsigned             indent)
{
  if (!decl)
    return false;

  ostream& o = ctxt.get_ostream();
  do_indent_to_level(ctxt, indent, 0);

  string id_attr_name = "id";
  if (ctxt.type_has_existing_id(decl))
    id_attr_name = "type-id";

  o << "<template-template-parameter " << id_attr_name << "='"
    << ctxt.get_id_for_type(decl) << "'";

  string name = xml::escape_xml_string(decl->get_name());
  if (!name.empty())
    o << " name='" << name << "'";

  o << ">\n";

  unsigned nb_spaces = get_indent_to_level(ctxt, indent, 1);
  for (list<shared_ptr<template_parameter> >::const_iterator p =
     decl->get_template_parameters().begin();
       p != decl->get_template_parameters().end();
       ++p)
    write_template_parameter(decl, ctxt, nb_spaces);

  do_indent_to_level(ctxt, indent, 0);
  o << "</template-template-parameter>\n";

  ctxt.record_type_as_emitted(decl);

  return true;
}

/// Serialize an instance of type_composition.
///
/// @param decl the decl to serialize.
///
/// @param ctxt the context of the serialization.
///
/// @param indent the initial indentation to use.
///
/// @return true upon successful completion, false otherwise.
static bool
write_type_composition
(const shared_ptr<type_composition> decl,
 write_context& ctxt, unsigned indent)
{
  if (!decl)
    return false;

  ostream& o = ctxt.get_ostream();

  do_indent_to_level(ctxt, indent, 0);

  o << "<template-parameter-type-composition>\n";

  unsigned nb_spaces = get_indent_to_level(ctxt, indent, 1);
  (write_pointer_type_def
   (dynamic_pointer_cast<pointer_type_def>(decl->get_composed_type()),
              ctxt, nb_spaces)
   || write_reference_type_def
   (dynamic_pointer_cast<reference_type_def>(decl->get_composed_type()),
    ctxt, nb_spaces)
   || write_array_type_def
   (dynamic_pointer_cast<array_type_def>(decl->get_composed_type()),
    ctxt, nb_spaces)
   || write_qualified_type_def
   (dynamic_pointer_cast<qualified_type_def>(decl->get_composed_type()),
    ctxt, nb_spaces));

  do_indent_to_level(ctxt, indent, 0);
  o << "</template-parameter-type-composition>\n";

  return true;
}

/// Serialize an instance of template_parameter.
///
/// @param decl the instance to serialize.
///
/// @param ctxt the context of the serialization.
///
/// @param indent the initial indentation to use.
///
/// @return true upon successful completion, false otherwise.
static bool
write_template_parameter(const shared_ptr<template_parameter> decl,
             write_context& ctxt, unsigned indent)
{
  if ((!write_type_tparameter
       (dynamic_pointer_cast<type_tparameter>(decl), ctxt, indent))
      && (!write_non_type_tparameter
      (dynamic_pointer_cast<non_type_tparameter>(decl),
       ctxt, indent))
      && (!write_template_tparameter
      (dynamic_pointer_cast<template_tparameter>(decl),
       ctxt, indent))
      && (!write_type_composition
      (dynamic_pointer_cast<type_composition>(decl),
       ctxt, indent)))
    return false;

  return true;
}

/// Serialize the template parameters of the a given template.
///
/// @param tmpl the template for which to emit the template parameters.
static void
write_template_parameters(const shared_ptr<template_decl> tmpl,
              write_context& ctxt, unsigned indent)
{
  if (!tmpl)
    return;

  unsigned nb_spaces = get_indent_to_level(ctxt, indent, 1);
  for (list<shared_ptr<template_parameter> >::const_iterator p =
     tmpl->get_template_parameters().begin();
       p != tmpl->get_template_parameters().end();
       ++p)
    write_template_parameter(*p, ctxt, nb_spaces);
}

/// Serialize an instance of function_tdecl.
///
/// @param decl the instance to serialize.
///
/// @param ctxt the context of the serialization
///
/// @param indent the initial indentation.
static bool
write_function_tdecl(const shared_ptr<function_tdecl> decl,
             write_context& ctxt, unsigned indent)
{
  if (!decl)
    return false;

  ostream& o = ctxt.get_ostream();

  do_indent_to_level(ctxt, indent, 0);

  o << "<function-template-decl id='" << ctxt.get_id_for_fn_tmpl(decl) << "'";

  write_location(decl, ctxt);

  write_visibility(decl, o);

  write_binding(decl, o);

  o << ">\n";

  write_template_parameters(decl, ctxt, indent);

  write_function_decl(decl->get_pattern(), ctxt,
              /*skip_first_parameter=*/false,
              get_indent_to_level(ctxt, indent, 1));

  do_indent_to_level(ctxt, indent, 0);

  o << "</function-template-decl>\n";

  return true;
}


/// Serialize an instance of class_tdecl
///
/// @param decl a pointer to the instance of class_tdecl to serialize.
///
/// @param ctxt the context of the serializtion.
///
/// @param indent the initial number of white space to use for
/// indentation.
///
/// @return true upon successful completion, false otherwise.
static bool
write_class_tdecl(const shared_ptr<class_tdecl> decl,
          write_context& ctxt, unsigned indent)
{
  if (!decl)
    return false;

  ostream& o = ctxt.get_ostream();

  do_indent_to_level(ctxt, indent, 0);

  o << "<class-template-decl id='" << ctxt.get_id_for_class_tmpl(decl) << "'";

  write_location(decl, ctxt);

  write_visibility(decl, o);

  o << ">\n";

  write_template_parameters(decl, ctxt, indent);

  write_class_decl(decl->get_pattern(), ctxt,
           get_indent_to_level(ctxt, indent, 1));

  do_indent_to_level(ctxt, indent, 0);

  o << "</class-template-decl>\n";

  return true;
}

/// Serialize the current version number of the ABIXML format.
///
/// @param ctxt the writing context to use.
static void
write_version_info(write_context& ctxt)
{
  ostream& o = ctxt.get_ostream();
  const config& c = ctxt.get_config();

  o << "version='"
    << c.get_format_major_version_number()
    << "." << c.get_format_minor_version_number()
    << "'";
}

/// Serialize an ABI corpus to a single native xml document.  The root
/// note of the resulting XML document is 'abi-corpus'.
///
/// Note: If either corpus is null or corpus does not contain serializable
///       content (i.e. corpus.is_empty()), nothing is emitted to the ctxt's
///       output stream.
///
/// @param ctxt the write context to use.
///
/// @param corpus the corpus to serialize.
///
/// @param indent the number of white space indentation to use.
///
/// @return true upon successful completion, false otherwise.
bool
write_corpus(write_context& ctxt,
         const corpus_sptr& corpus,
         unsigned       indent,
         bool       member_of_group)
{
  if (!corpus)
    return false;

  if (corpus->is_empty())
    return true;

  do_indent_to_level(ctxt, indent, 0);

  std::ostream& out = ctxt.get_ostream();

  out << "<abi-corpus ";

  write_version_info(ctxt);

  // For an abi-corpus as part of an abi-corpus group, only omit the path, but
  // keep the filename.
  std::string corpus_path = corpus->get_path();
  if (!ctxt.get_write_corpus_path())
    {
      if (member_of_group)
    tools_utils::base_name(corpus_path, corpus_path);
      else
    corpus_path.clear();
    }
  else
    {
      if (ctxt.get_short_locs())
    tools_utils::base_name(corpus_path, corpus_path);
    }
  if (!corpus_path.empty())
    out << " path='" << xml::escape_xml_string(corpus_path) << "'";

  if (!corpus->get_architecture_name().empty()
      && ctxt.get_write_architecture())
    out << " architecture='" << corpus->get_architecture_name()<< "'";

  if (!corpus->get_soname().empty())
    out << " soname='" << corpus->get_soname()<< "'";

  write_tracking_non_reachable_types(corpus, out);

  out << ">\n";

  // Write the list of needed corpora.

  if (ctxt.get_write_elf_needed () && !corpus->get_needed().empty())
    {
      do_indent_to_level(ctxt, indent, 1);
      out << "<elf-needed>\n";
      write_elf_needed(corpus->get_needed(), ctxt,
               get_indent_to_level(ctxt, indent, 2));
      do_indent_to_level(ctxt, indent, 1);
      out << "</elf-needed>\n";
    }

  // Write the function symbols data base.
  if (!corpus->get_fun_symbol_map().empty())
    {
      do_indent_to_level(ctxt, indent, 1);
      out << "<elf-function-symbols>\n";

      write_elf_symbols_table(corpus->get_sorted_fun_symbols(), ctxt,
                  get_indent_to_level(ctxt, indent, 2));

      do_indent_to_level(ctxt, indent, 1);
      out << "</elf-function-symbols>\n";
    }

  // Write the variable symbols data base.
  if (!corpus->get_var_symbol_map().empty())
    {
      do_indent_to_level(ctxt, indent, 1);
      out << "<elf-variable-symbols>\n";

      write_elf_symbols_table(corpus->get_sorted_var_symbols(), ctxt,
                  get_indent_to_level(ctxt, indent, 2));

      do_indent_to_level(ctxt, indent, 1);
      out << "</elf-variable-symbols>\n";
    }

  // Write the undefined function symbols database.
  if (ctxt.get_write_undefined_symbols()
      && !corpus->get_sorted_undefined_fun_symbols().empty())
    {
      do_indent_to_level(ctxt, indent, 1);
      out << "<undefined-elf-function-symbols>\n";

      write_elf_symbols_table(corpus->get_sorted_undefined_fun_symbols(), ctxt,
                  get_indent_to_level(ctxt, indent, 2));

      do_indent_to_level(ctxt, indent, 1);
      out << "</undefined-elf-function-symbols>\n";
    }


  // Write the undefined variable symbols database.
    if (ctxt.get_write_undefined_symbols()
    && !corpus->get_sorted_undefined_var_symbols().empty())
    {
      do_indent_to_level(ctxt, indent, 1);
      out << "<undefined-elf-variable-symbols>\n";

      write_elf_symbols_table(corpus->get_sorted_undefined_var_symbols(), ctxt,
                  get_indent_to_level(ctxt, indent, 2));

      do_indent_to_level(ctxt, indent, 1);
      out << "</undefined-elf-variable-symbols>\n";
    }

  // Now write the translation units.
  unsigned nb_tus = corpus->get_translation_units().size(), n = 0;
  for (translation_units::const_iterator i =
     corpus->get_translation_units().begin();
       i != corpus->get_translation_units().end();
       ++i, ++n)
    {
      translation_unit& tu = **i;
      write_translation_unit(ctxt, tu,
                 get_indent_to_level(ctxt, indent, 1),
                 n == nb_tus - 1);
    }

  do_indent_to_level(ctxt, indent, 0);
  out << "</abi-corpus>\n";

  ctxt.clear_referenced_types();
  ctxt.record_corpus_as_emitted(corpus);

  return true;
}

/// Serialize an ABI corpus group to a single native xml document.
/// The root note of the resulting XML document is 'abi-corpus-group'.
///
/// @param ctxt the write context to use.
///
/// @param group the corpus group to serialize.
///
/// @param indent the number of white space indentation to use.
///
/// @return true upon successful completion, false otherwise.
bool
write_corpus_group(write_context&       ctxt,
           const corpus_group_sptr& group,
           unsigned         indent)

{
  if (!group)
    return false;

  do_indent_to_level(ctxt, indent, 0);

std::ostream& out = ctxt.get_ostream();

  out << "<abi-corpus-group ";
  write_version_info(ctxt);

  if (!group->get_path().empty() && ctxt.get_write_corpus_path())
    out << " path='" << xml::escape_xml_string(group->get_path()) << "'";

  if (!group->get_architecture_name().empty() && ctxt.get_write_architecture())
    out << " architecture='" << group->get_architecture_name()<< "'";

  write_tracking_non_reachable_types(group, out);

  if (group->is_empty())
    {
      out << "/>\n";
      return true;
    }

  out << ">\n";

  // Write the list of corpora
  for (corpus_group::corpora_type::const_iterator c =
     group->get_corpora().begin();
       c != group->get_corpora().end();
       ++c)
    {
      ABG_ASSERT(!ctxt.corpus_is_emitted(*c));
      write_corpus(ctxt, *c, get_indent_to_level(ctxt, indent, 1), true);
    }

  do_indent_to_level(ctxt, indent, 0);
  out << "</abi-corpus-group>\n";

  return true;
}

} //end namespace xml_writer

// <Debugging routines>

using namespace abigail::ir;

/// Serialize a pointer to decl_base to an output stream.
///
/// @param d the pointer to decl_base to serialize.
///
/// @param o the output stream to consider.
///
/// @param annotate whether ABIXML output should be annotated.
void
dump(const decl_base_sptr d, std::ostream& o, const bool annotate)
{
  xml_writer::write_context ctxt(d->get_environment(), o);
  xml_writer::set_annotate(ctxt, annotate);
  write_decl(d, ctxt, /*indent=*/0);
}

/// Serialize a pointer to decl_base to stderr.
///
/// @param d the pointer to decl_base to serialize.
///
/// @param annotate whether ABIXML output should be annotated.
void
dump(const decl_base_sptr d, const bool annotate)
{dump(d, cerr, annotate);}

/// Serialize a pointer to type_base to an output stream.
///
/// @param t the pointer to type_base to serialize.
///
/// @param o the output stream to serialize the @ref type_base to.
///
/// @param annotate whether ABIXML output should be annotated.
void
dump(const type_base_sptr t, std::ostream& o, const bool annotate)
{dump(get_type_declaration(t), o, annotate);}

/// Serialize a pointer to type_base to stderr.
///
/// @param t the pointer to type_base to serialize.
///
/// @param annotate whether ABIXML output should be annotated.
void
dump(const type_base_sptr t, const bool annotate)
{dump(t, cerr, annotate);}

/// Serialize a pointer to var_decl to an output stream.
///
/// @param v the pointer to var_decl to serialize.
///
/// @param o the output stream to serialize the @ref var_decl to.
///
/// @param annotate whether ABIXML output should be annotated.
void
dump(const var_decl_sptr v, std::ostream& o, const bool annotate)
{
  xml_writer::write_context ctxt(v->get_environment(), o);
  xml_writer::set_annotate(ctxt, annotate);
  write_var_decl(v, ctxt, /*linkage_name*/true, /*indent=*/0);
}

/// Serialize a pointer to var_decl to stderr.
///
/// @param v the pointer to var_decl to serialize.
///
/// @param annotate whether ABIXML output should be annotated.
void
dump(const var_decl_sptr v, const bool annotate)
{dump(v, cerr, annotate);}

/// Serialize a @ref translation_unit to an output stream.
///
/// @param t the translation_unit to serialize.
///
/// @param o the outpout stream to serialize the translation_unit to.
///
/// @param annotate whether ABIXML output should be annotated.
void
dump(const translation_unit& t, std::ostream& o, const bool annotate)
{
  xml_writer::write_context ctxt(t.get_environment(), o);
  xml_writer::set_annotate(ctxt, annotate);
  write_translation_unit(ctxt, t, /*indent=*/0);
}

/// Serialize an instance of @ref translation_unit to stderr.
///
/// @param t the translation_unit to serialize.
void
dump(const translation_unit& t, const bool annotate)
{dump(t, cerr, annotate);}

/// Serialize a pointer to @ref translation_unit to an output stream.
///
/// @param t the @ref translation_unit_sptr to serialize.
///
/// @param o the output stream to serialize the translation unit to.
///
/// @param annotate whether ABIXML output should be annotated.
void
dump(const translation_unit_sptr t, std::ostream& o, const bool annotate)
{
  if (t)
    dump(*t, o, annotate);
}

/// Serialize a pointer to @ref translation_unit to stderr.
///
/// @param t the translation_unit_sptr to serialize.
///
/// @param annotate whether ABIXML output should be annotated.
void
dump(const translation_unit_sptr t, const bool annotate)
{
  if (t)
    dump(*t, annotate);
}

/// Serialize a source location to an output stream.
///
/// @param l the declaration to consider.
///
/// @param o the output stream to serialize to.
void
dump_location(const location& l, ostream& o)
{
  string path;
  unsigned line = 0, col = 0;

  l.expand(path, line, col);
  o << path << ":" << line << "," << col << "\n";
}

/// Serialize a source location for debugging purposes.
///
/// The location is serialized to the standard error output stream.
///
/// @param l the declaration to consider.
///
void
dump_location(const location& l)
{dump_location(l, cerr);}

/// Serialize the source location of a decl to an output stream for
/// debugging purposes.
///
/// @param d the declaration to consider.
///
/// @param o the output stream to serizalize the location to.
void
dump_decl_location(const decl_base& d, ostream& o)
{dump_location(d.get_location(), o);}

/// Serialize the source location of a decl to stderr for debugging
/// purposes.
///
/// @param d the declaration to consider.
void
dump_decl_location(const decl_base& d)
{dump_decl_location(d, cerr);}

/// Serialize the source location of a dcl to stderr for debugging
/// purposes.
///
/// @param d the declaration to consider.
void
dump_decl_location(const decl_base* d)
{
  if (d)
    dump_decl_location(*d);
}

/// Serialize the source location of a decl to stderr for debugging
/// purposes.
///
/// @param d the declaration to consider.
void
dump_decl_location(const decl_base_sptr d)
{dump_decl_location(d.get());}

#ifdef WITH_DEBUG_SELF_COMPARISON
/// Write one of the records of the "type-ids" debugging file.
///
/// This is a sub-routine of write_canonical_type_ids.
///
/// @param ctxt the context to use.
///
/// @param type the type which canonical type pointer value to emit.
///
/// @param o the output stream to write to.
static void
write_type_record(xml_writer::write_context&    ctxt,
          const type_base*      type,
          ostream&          o)
{
  // We want to serialize a type record which content looks like:
  //
  //     <type>
  //       <id>type-id-573</id>
  //       <c>0x262ee28</c>
  //     </type>
  //     <type>
  //       <id>type-id-569</id>
  //       <c>0x2628298</c>
  //     </type>
  //     <type>
  //       <id>type-id-575</id>
  //       <c>0x25f9ba8</c>
  //     </type>

    type_base* canonical = type->get_naked_canonical_type();
    string id ;
  if (canonical)
    {
      id = ctxt.get_id_for_type (const_cast<type_base*>(type));

      o << "  <type>\n"
    << "    <id>" << id << "</id>\n"
    << "    <c>"
    << std::hex
    << reinterpret_cast<uintptr_t>(canonical)
    << "</c>\n"
    << "  </type>\n";
    }
}

/// Serialize the map that is stored at
/// environment::get_type_id_canonical_type_map() to an output stream.
///
/// This is for debugging purposes and is triggered ultimately by
/// invoking the command 'abidw --debug-abidiff <binary>'.
///
/// @param ctxt the write context.
///
/// @param o the output stream to serialize the map to.
void
write_canonical_type_ids(xml_writer::write_context& ctxt, ostream& o)
{
  // We want to serialize a file which content looks like:
  //
  // <abixml-types-check>
  //     <type>
  //       <id>type-id-573</id>
  //       <c>0x262ee28</c>
  //     </type>
  //     <type>
  //       <id>type-id-569</id>
  //       <c>0x2628298</c>
  //     </type>
  //     <type>
  //       <id>type-id-575</id>
  //       <c>0x25f9ba8</c>
  //     </type>
  // <abixml-types-check>

  o << "<abixml-types-check>\n";

  for (const auto &type : ctxt.get_emitted_types_set())
    write_type_record(ctxt, type, o);

  o << "</abixml-types-check>\n";
}

/// Serialize the map that is stored at
/// environment::get_type_id_canonical_type_map() to a file.
///
/// This is for debugging purposes and is triggered ultimately by
/// invoking the command 'abidw --debug-abidiff <binary>'.
///
/// @param ctxt the write context.
///
/// @param file_path the file to serialize the map to.
bool
write_canonical_type_ids(xml_writer::write_context& ctxt,
            const string &file_path)
{
  std:: ofstream o (file_path);

  if (!o.is_open())
    return true;
  write_canonical_type_ids(ctxt, o);
  o.close();
  return true;
}
#endif
// </Debugging routines>
} //end namespace abigail