gdb/python/py-type.c

/* Python interface to types.

   Copyright (C) 2008, 2009, 2010, 2011 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"
#include "value.h"
#include "exceptions.h"
#include "python-internal.h"
#include "charset.h"
#include "gdbtypes.h"
#include "cp-support.h"
#include "demangle.h"
#include "objfiles.h"
#include "language.h"
#include "vec.h"
#include "bcache.h"

typedef struct pyty_type_object
{
  PyObject_HEAD
  struct type *type;

  /* If a Type object is associated with an objfile, it is kept on a
     doubly-linked list, rooted in the objfile.  This lets us copy the
     underlying struct type when the objfile is deleted.  */
  struct pyty_type_object *prev;
  struct pyty_type_object *next;
} type_object;

static PyTypeObject type_object_type;

/* A Field object.  */
typedef struct pyty_field_object
{
  PyObject_HEAD

  /* Dictionary holding our attributes.  */
  PyObject *dict;
} field_object;

static PyTypeObject field_object_type;

/* This is used to initialize various gdb.TYPE_ constants.  */
struct pyty_code
{
  /* The code.  */
  enum type_code code;
  /* The name.  */
  const char *name;
};

#define ENTRY(X) { X, #X }

static struct pyty_code pyty_codes[] =
{
  ENTRY (TYPE_CODE_PTR),
  ENTRY (TYPE_CODE_ARRAY),
  ENTRY (TYPE_CODE_STRUCT),
  ENTRY (TYPE_CODE_UNION),
  ENTRY (TYPE_CODE_ENUM),
  ENTRY (TYPE_CODE_FLAGS),
  ENTRY (TYPE_CODE_FUNC),
  ENTRY (TYPE_CODE_INT),
  ENTRY (TYPE_CODE_FLT),
  ENTRY (TYPE_CODE_VOID),
  ENTRY (TYPE_CODE_SET),
  ENTRY (TYPE_CODE_RANGE),
  ENTRY (TYPE_CODE_STRING),
  ENTRY (TYPE_CODE_BITSTRING),
  ENTRY (TYPE_CODE_ERROR),
  ENTRY (TYPE_CODE_METHOD),
  ENTRY (TYPE_CODE_METHODPTR),
  ENTRY (TYPE_CODE_MEMBERPTR),
  ENTRY (TYPE_CODE_REF),
  ENTRY (TYPE_CODE_CHAR),
  ENTRY (TYPE_CODE_BOOL),
  ENTRY (TYPE_CODE_COMPLEX),
  ENTRY (TYPE_CODE_TYPEDEF),
  ENTRY (TYPE_CODE_NAMESPACE),
  ENTRY (TYPE_CODE_DECFLOAT),
  ENTRY (TYPE_CODE_INTERNAL_FUNCTION),
  { TYPE_CODE_UNDEF, NULL }
};



static void
field_dealloc (PyObject *obj)
{
  field_object *f = (field_object *) obj;

  Py_XDECREF (f->dict);
  f->ob_type->tp_free (obj);
}

static PyObject *
field_new (void)
{
  field_object *result = PyObject_New (field_object, &field_object_type);

  if (result)
    {
      result->dict = PyDict_New ();
      if (!result->dict)
	{
	  Py_DECREF (result);
	  result = NULL;
	}
    }
  return (PyObject *) result;
}



/* Return the code for this type.  */
static PyObject *
typy_get_code (PyObject *self, void *closure)
{
  struct type *type = ((type_object *) self)->type;

  return PyInt_FromLong (TYPE_CODE (type));
}

/* Helper function for typy_fields which converts a single field to a
   dictionary.  Returns NULL on error.  */
static PyObject *
convert_field (struct type *type, int field)
{
  PyObject *result = field_new ();
  PyObject *arg;

  if (!result)
    return NULL;

  if (!field_is_static (&TYPE_FIELD (type, field)))
    {
      arg = PyLong_FromLong (TYPE_FIELD_BITPOS (type, field));
      if (!arg)
	goto fail;

      if (PyObject_SetAttrString (result, "bitpos", arg) < 0)
	goto failarg;
    }

  if (TYPE_FIELD_NAME (type, field))
    arg = PyString_FromString (TYPE_FIELD_NAME (type, field));
  else
    {
      arg = Py_None;
      Py_INCREF (arg);
    }
  if (!arg)
    goto fail;
  if (PyObject_SetAttrString (result, "name", arg) < 0)
    goto failarg;

  arg = TYPE_FIELD_ARTIFICIAL (type, field) ? Py_True : Py_False;
  Py_INCREF (arg);
  if (PyObject_SetAttrString (result, "artificial", arg) < 0)
    goto failarg;

  if (TYPE_CODE (type) == TYPE_CODE_CLASS)
    arg = field < TYPE_N_BASECLASSES (type) ? Py_True : Py_False;
  else
    arg = Py_False;
  Py_INCREF (arg);
  if (PyObject_SetAttrString (result, "is_base_class", arg) < 0)
    goto failarg;

  arg = PyLong_FromLong (TYPE_FIELD_BITSIZE (type, field));
  if (!arg)
    goto fail;
  if (PyObject_SetAttrString (result, "bitsize", arg) < 0)
    goto failarg;

  /* A field can have a NULL type in some situations.  */
  if (TYPE_FIELD_TYPE (type, field) == NULL)
    {
      arg = Py_None;
      Py_INCREF (arg);
    }
  else
    arg = type_to_type_object (TYPE_FIELD_TYPE (type, field));
  if (!arg)
    goto fail;
  if (PyObject_SetAttrString (result, "type", arg) < 0)
    goto failarg;

  return result;

 failarg:
  Py_DECREF (arg);
 fail:
  Py_DECREF (result);
  return NULL;
}

/* Return a sequence of all fields.  Each field is a dictionary with
   some pre-defined keys.  */
static PyObject *
typy_fields (PyObject *self, PyObject *args)
{
  PyObject *result;
  int i;
  struct type *type = ((type_object *) self)->type;
  volatile struct gdb_exception except;

  TRY_CATCH (except, RETURN_MASK_ALL)
    {
      CHECK_TYPEDEF (type);
    }
  GDB_PY_HANDLE_EXCEPTION (except);

  /* We would like to make a tuple here, make fields immutable, and
     then memoize the result (and perhaps make Field.type() lazy).
     However, that can lead to cycles.  */
  result = PyList_New (0);

  for (i = 0; i < TYPE_NFIELDS (type); ++i)
    {
      PyObject *dict = convert_field (type, i);

      if (!dict)
	{
	  Py_DECREF (result);
	  return NULL;
	}
      if (PyList_Append (result, dict))
	{
	  Py_DECREF (dict);
	  Py_DECREF (result);
	  return NULL;
	}
    }

  return result;
}

/* Return the type's tag, or None.  */
static PyObject *
typy_get_tag (PyObject *self, void *closure)
{
  struct type *type = ((type_object *) self)->type;

  if (!TYPE_TAG_NAME (type))
    Py_RETURN_NONE;
  return PyString_FromString (TYPE_TAG_NAME (type));
}

/* Return the type, stripped of typedefs. */
static PyObject *
typy_strip_typedefs (PyObject *self, PyObject *args)
{
  struct type *type = ((type_object *) self)->type;

  return type_to_type_object (check_typedef (type));
}

/* Return an array type.  */

static PyObject *
typy_array (PyObject *self, PyObject *args)
{
  long n1, n2;
  PyObject *n2_obj = NULL;
  struct type *array = NULL;
  struct type *type = ((type_object *) self)->type;
  volatile struct gdb_exception except;

  if (! PyArg_ParseTuple (args, "l|O", &n1, &n2_obj))
    return NULL;

  if (n2_obj)
    {
      if (!PyInt_Check (n2_obj))
	{
	  PyErr_SetString (PyExc_RuntimeError,
			   _("Array bound must be an integer"));
	  return NULL;
	}

      if (! gdb_py_int_as_long (n2_obj, &n2))
	return NULL;
    }
  else
    {
      n2 = n1;
      n1 = 0;
    }

  if (n2 < n1)
    {
      PyErr_SetString (PyExc_ValueError,
		       _("Array length must not be negative"));
      return NULL;
    }

  TRY_CATCH (except, RETURN_MASK_ALL)
    {
      array = lookup_array_range_type (type, n1, n2);
    }
  GDB_PY_HANDLE_EXCEPTION (except);

  return type_to_type_object (array);
}

/* Return a Type object which represents a pointer to SELF.  */
static PyObject *
typy_pointer (PyObject *self, PyObject *args)
{
  struct type *type = ((type_object *) self)->type;
  volatile struct gdb_exception except;

  TRY_CATCH (except, RETURN_MASK_ALL)
    {
      type = lookup_pointer_type (type);
    }
  GDB_PY_HANDLE_EXCEPTION (except);

  return type_to_type_object (type);
}

/* Return the range of a type represented by SELF.  The return type is
   a tuple.  The first element of the tuple contains the low bound,
   while the second element of the tuple contains the high bound.  */
static PyObject *
typy_range (PyObject *self, PyObject *args)
{
  struct type *type = ((type_object *) self)->type;
  PyObject *result;
  PyObject *low_bound = NULL, *high_bound = NULL;
  /* Initialize these to appease GCC warnings.  */
  LONGEST low = 0, high = 0;

  if (TYPE_CODE (type) != TYPE_CODE_ARRAY
      && TYPE_CODE (type) != TYPE_CODE_STRING
      && TYPE_CODE (type) != TYPE_CODE_RANGE)
    {
      PyErr_SetString (PyExc_RuntimeError,
		       _("This type does not have a range."));
      return NULL;
    }

  switch (TYPE_CODE (type))
    {
    case TYPE_CODE_ARRAY:
    case TYPE_CODE_STRING:
      low = TYPE_LOW_BOUND (TYPE_INDEX_TYPE (type));
      high = TYPE_HIGH_BOUND (TYPE_INDEX_TYPE (type));
      break;
    case TYPE_CODE_RANGE:
      low = TYPE_LOW_BOUND (type);
      high = TYPE_HIGH_BOUND (type);
      break;
    }

  low_bound = PyLong_FromLong (low);
  if (!low_bound)
    goto failarg;

  high_bound = PyLong_FromLong (high);
  if (!high_bound)
    goto failarg;

  result = PyTuple_New (2);
  if (!result)
    goto failarg;

  if (PyTuple_SetItem (result, 0, low_bound) != 0)
    {
      Py_DECREF (result);
      goto failarg;
    }
  if (PyTuple_SetItem (result, 1, high_bound) != 0)
    {
      Py_DECREF (high_bound);
      Py_DECREF (result);
      return NULL;
    }
  return result;
  
 failarg:
  Py_XDECREF (high_bound);
  Py_XDECREF (low_bound);
  return NULL;
}

/* Return a Type object which represents a reference to SELF.  */
static PyObject *
typy_reference (PyObject *self, PyObject *args)
{
  struct type *type = ((type_object *) self)->type;
  volatile struct gdb_exception except;

  TRY_CATCH (except, RETURN_MASK_ALL)
    {
      type = lookup_reference_type (type);
    }
  GDB_PY_HANDLE_EXCEPTION (except);

  return type_to_type_object (type);
}

/* Return a Type object which represents the target type of SELF.  */
static PyObject *
typy_target (PyObject *self, PyObject *args)
{
  struct type *type = ((type_object *) self)->type;

  if (!TYPE_TARGET_TYPE (type))
    {
      PyErr_SetString (PyExc_RuntimeError, 
		       _("Type does not have a target."));
      return NULL;
    }

  return type_to_type_object (TYPE_TARGET_TYPE (type));
}

/* Return a const-qualified type variant.  */
static PyObject *
typy_const (PyObject *self, PyObject *args)
{
  struct type *type = ((type_object *) self)->type;
  volatile struct gdb_exception except;

  TRY_CATCH (except, RETURN_MASK_ALL)
    {
      type = make_cv_type (1, 0, type, NULL);
    }
  GDB_PY_HANDLE_EXCEPTION (except);

  return type_to_type_object (type);
}

/* Return a volatile-qualified type variant.  */
static PyObject *
typy_volatile (PyObject *self, PyObject *args)
{
  struct type *type = ((type_object *) self)->type;
  volatile struct gdb_exception except;

  TRY_CATCH (except, RETURN_MASK_ALL)
    {
      type = make_cv_type (0, 1, type, NULL);
    }
  GDB_PY_HANDLE_EXCEPTION (except);

  return type_to_type_object (type);
}

/* Return an unqualified type variant.  */
static PyObject *
typy_unqualified (PyObject *self, PyObject *args)
{
  struct type *type = ((type_object *) self)->type;
  volatile struct gdb_exception except;

  TRY_CATCH (except, RETURN_MASK_ALL)
    {
      type = make_cv_type (0, 0, type, NULL);
    }
  GDB_PY_HANDLE_EXCEPTION (except);

  return type_to_type_object (type);
}

/* Return the size of the type represented by SELF, in bytes.  */
static PyObject *
typy_get_sizeof (PyObject *self, void *closure)
{
  struct type *type = ((type_object *) self)->type;
  volatile struct gdb_exception except;

  TRY_CATCH (except, RETURN_MASK_ALL)
    {
      check_typedef (type);
    }
  /* Ignore exceptions.  */

  return PyLong_FromLong (TYPE_LENGTH (type));
}

static struct type *
typy_lookup_typename (char *type_name, struct block *block)
{
  struct type *type = NULL;
  volatile struct gdb_exception except;

  TRY_CATCH (except, RETURN_MASK_ALL)
    {
      if (!strncmp (type_name, "struct ", 7))
	type = lookup_struct (type_name + 7, NULL);
      else if (!strncmp (type_name, "union ", 6))
	type = lookup_union (type_name + 6, NULL);
      else if (!strncmp (type_name, "enum ", 5))
	type = lookup_enum (type_name + 5, NULL);
      else
	type = lookup_typename (python_language, python_gdbarch,
				type_name, block, 0);
    }
  if (except.reason < 0)
    {
      PyErr_Format (except.reason == RETURN_QUIT
		    ? PyExc_KeyboardInterrupt : PyExc_RuntimeError,
		    "%s", except.message);
      return NULL;
    }

  return type;
}

static struct type *
typy_lookup_type (struct demangle_component *demangled,
		  struct block *block)
{
  struct type *type;
  char *type_name;
  enum demangle_component_type demangled_type;

  /* Save the type: typy_lookup_type() may (indirectly) overwrite
     memory pointed by demangled.  */
  demangled_type = demangled->type;

  if (demangled_type == DEMANGLE_COMPONENT_POINTER
      || demangled_type == DEMANGLE_COMPONENT_REFERENCE
      || demangled_type == DEMANGLE_COMPONENT_CONST
      || demangled_type == DEMANGLE_COMPONENT_VOLATILE)
    {
      type = typy_lookup_type (demangled->u.s_binary.left, block);
      if (! type)
	return NULL;

      switch (demangled_type)
	{
	case DEMANGLE_COMPONENT_REFERENCE:
	  return lookup_reference_type (type);
	case DEMANGLE_COMPONENT_POINTER:
	  return lookup_pointer_type (type);
	case DEMANGLE_COMPONENT_CONST:
	  return make_cv_type (1, 0, type, NULL);
	case DEMANGLE_COMPONENT_VOLATILE:
	  return make_cv_type (0, 1, type, NULL);
	}
    }

  type_name = cp_comp_to_string (demangled, 10);
  type = typy_lookup_typename (type_name, block);
  xfree (type_name);

  return type;
}

/* This is a helper function for typy_template_argument that is used
   when the type does not have template symbols attached.  It works by
   parsing the type name.  This happens with compilers, like older
   versions of GCC, that do not emit DW_TAG_template_*.  */

static PyObject *
typy_legacy_template_argument (struct type *type, struct block *block,
			       int argno)
{
  int i;
  struct demangle_component *demangled;
  const char *err;
  struct type *argtype;

  if (TYPE_NAME (type) == NULL)
    {
      PyErr_SetString (PyExc_RuntimeError, _("Null type name."));
      return NULL;
    }

  /* Note -- this is not thread-safe.  */
  demangled = cp_demangled_name_to_comp (TYPE_NAME (type), &err);
  if (! demangled)
    {
      PyErr_SetString (PyExc_RuntimeError, err);
      return NULL;
    }

  /* Strip off component names.  */
  while (demangled->type == DEMANGLE_COMPONENT_QUAL_NAME
	 || demangled->type == DEMANGLE_COMPONENT_LOCAL_NAME)
    demangled = demangled->u.s_binary.right;

  if (demangled->type != DEMANGLE_COMPONENT_TEMPLATE)
    {
      PyErr_SetString (PyExc_RuntimeError, _("Type is not a template."));
      return NULL;
    }

  /* Skip from the template to the arguments.  */
  demangled = demangled->u.s_binary.right;

  for (i = 0; demangled && i < argno; ++i)
    demangled = demangled->u.s_binary.right;

  if (! demangled)
    {
      PyErr_Format (PyExc_RuntimeError, _("No argument %d in template."),
		    argno);
      return NULL;
    }

  argtype = typy_lookup_type (demangled->u.s_binary.left, block);
  if (! argtype)
    return NULL;

  return type_to_type_object (argtype);
}

static PyObject *
typy_template_argument (PyObject *self, PyObject *args)
{
  int argno;
  struct type *type = ((type_object *) self)->type;
  struct block *block = NULL;
  PyObject *block_obj = NULL;
  struct symbol *sym;
  struct value *val = NULL;
  volatile struct gdb_exception except;

  if (! PyArg_ParseTuple (args, "i|O", &argno, &block_obj))
    return NULL;

  if (block_obj)
    {
      block = block_object_to_block (block_obj);
      if (! block)
	{
	  PyErr_SetString (PyExc_RuntimeError,
			   _("Second argument must be block."));
	  return NULL;
	}
    }

  TRY_CATCH (except, RETURN_MASK_ALL)
    {
      type = check_typedef (type);
      if (TYPE_CODE (type) == TYPE_CODE_REF)
	type = check_typedef (TYPE_TARGET_TYPE (type));
    }
  GDB_PY_HANDLE_EXCEPTION (except);

  /* We might not have DW_TAG_template_*, so try to parse the type's
     name.  This is inefficient if we do not have a template type --
     but that is going to wind up as an error anyhow.  */
  if (! TYPE_N_TEMPLATE_ARGUMENTS (type))
    return typy_legacy_template_argument (type, block, argno);

  if (argno >= TYPE_N_TEMPLATE_ARGUMENTS (type))
    {
      PyErr_Format (PyExc_RuntimeError, _("No argument %d in template."),
		    argno);
      return NULL;
    }

  sym = TYPE_TEMPLATE_ARGUMENT (type, argno);
  if (SYMBOL_CLASS (sym) == LOC_TYPEDEF)
    return type_to_type_object (SYMBOL_TYPE (sym));
  else if (SYMBOL_CLASS (sym) == LOC_OPTIMIZED_OUT)
    {
      PyErr_Format (PyExc_RuntimeError,
		    _("Template argument is optimized out"));
      return NULL;
    }

  TRY_CATCH (except, RETURN_MASK_ALL)
    {
      val = value_of_variable (sym, block);
    }
  GDB_PY_HANDLE_EXCEPTION (except);

  return value_to_value_object (val);
}

static PyObject *
typy_str (PyObject *self)
{
  volatile struct gdb_exception except;
  char *thetype = NULL;
  long length = 0;
  PyObject *result;

  TRY_CATCH (except, RETURN_MASK_ALL)
    {
      struct cleanup *old_chain;
      struct ui_file *stb;

      stb = mem_fileopen ();
      old_chain = make_cleanup_ui_file_delete (stb);

      type_print (type_object_to_type (self), "", stb, -1);

      thetype = ui_file_xstrdup (stb, &length);
      do_cleanups (old_chain);
    }
  if (except.reason < 0)
    {
      xfree (thetype);
      GDB_PY_HANDLE_EXCEPTION (except);
    }

  result = PyUnicode_Decode (thetype, length, host_charset (), NULL);
  xfree (thetype);

  return result;
}

/* An entry in the type-equality bcache.  */

typedef struct type_equality_entry
{
  struct type *type1, *type2;
} type_equality_entry_d;

DEF_VEC_O (type_equality_entry_d);

/* A helper function to compare two strings.  Returns 1 if they are
   the same, 0 otherwise.  Handles NULLs properly.  */

static int
compare_strings (const char *s, const char *t)
{
  if (s == NULL && t != NULL)
    return 0;
  else if (s != NULL && t == NULL)
    return 0;
  else if (s == NULL && t== NULL)
    return 1;
  return strcmp (s, t) == 0;
}

/* A helper function for typy_richcompare that checks two types for
   "deep" equality.  Returns Py_EQ if the types are considered the
   same, Py_NE otherwise.  */

static int
check_types_equal (struct type *type1, struct type *type2,
		   VEC (type_equality_entry_d) **worklist)
{
  CHECK_TYPEDEF (type1);
  CHECK_TYPEDEF (type2);

  if (type1 == type2)
    return Py_EQ;

  if (TYPE_CODE (type1) != TYPE_CODE (type2)
      || TYPE_LENGTH (type1) != TYPE_LENGTH (type2)
      || TYPE_UNSIGNED (type1) != TYPE_UNSIGNED (type2)
      || TYPE_NOSIGN (type1) != TYPE_NOSIGN (type2)
      || TYPE_VARARGS (type1) != TYPE_VARARGS (type2)
      || TYPE_VECTOR (type1) != TYPE_VECTOR (type2)
      || TYPE_NOTTEXT (type1) != TYPE_NOTTEXT (type2)
      || TYPE_INSTANCE_FLAGS (type1) != TYPE_INSTANCE_FLAGS (type2)
      || TYPE_NFIELDS (type1) != TYPE_NFIELDS (type2))
    return Py_NE;

  if (!compare_strings (TYPE_TAG_NAME (type1), TYPE_TAG_NAME (type2)))
    return Py_NE;
  if (!compare_strings (TYPE_NAME (type1), TYPE_NAME (type2)))
    return Py_NE;

  if (TYPE_CODE (type1) == TYPE_CODE_RANGE)
    {
      if (memcmp (TYPE_RANGE_DATA (type1), TYPE_RANGE_DATA (type2),
		  sizeof (*TYPE_RANGE_DATA (type1))) != 0)
	return Py_NE;
    }
  else
    {
      int i;

      for (i = 0; i < TYPE_NFIELDS (type1); ++i)
	{
	  const struct field *field1 = &TYPE_FIELD (type1, i);
	  const struct field *field2 = &TYPE_FIELD (type2, i);
	  struct type_equality_entry entry;

	  if (FIELD_ARTIFICIAL (*field1) != FIELD_ARTIFICIAL (*field2)
	      || FIELD_BITSIZE (*field1) != FIELD_BITSIZE (*field2)
	      || FIELD_LOC_KIND (*field1) != FIELD_LOC_KIND (*field2))
	    return Py_NE;
	  if (!compare_strings (FIELD_NAME (*field1), FIELD_NAME (*field2)))
	    return Py_NE;
	  switch (FIELD_LOC_KIND (*field1))
	    {
	    case FIELD_LOC_KIND_BITPOS:
	      if (FIELD_BITPOS (*field1) != FIELD_BITPOS (*field2))
		return Py_NE;
	      break;
	    case FIELD_LOC_KIND_PHYSADDR:
	      if (FIELD_STATIC_PHYSADDR (*field1)
		  != FIELD_STATIC_PHYSADDR (*field2))
		return Py_NE;
	      break;
	    case FIELD_LOC_KIND_PHYSNAME:
	      if (!compare_strings (FIELD_STATIC_PHYSNAME (*field1),
				    FIELD_STATIC_PHYSNAME (*field2)))
		return Py_NE;
	      break;
	    }

	  entry.type1 = FIELD_TYPE (*field1);
	  entry.type2 = FIELD_TYPE (*field2);
	  VEC_safe_push (type_equality_entry_d, *worklist, &entry);
	}
    }

  if (TYPE_TARGET_TYPE (type1) != NULL)
    {
      struct type_equality_entry entry;
      int added;

      if (TYPE_TARGET_TYPE (type2) == NULL)
	return Py_NE;

      entry.type1 = TYPE_TARGET_TYPE (type1);
      entry.type2 = TYPE_TARGET_TYPE (type2);
      VEC_safe_push (type_equality_entry_d, *worklist, &entry);
    }
  else if (TYPE_TARGET_TYPE (type2) != NULL)
    return Py_NE;

  return Py_EQ;
}

/* Check types on a worklist for equality.  Returns Py_NE if any pair
   is not equal, Py_EQ if they are all considered equal.  */

static int
check_types_worklist (VEC (type_equality_entry_d) **worklist,
		      struct bcache *cache)
{
  while (!VEC_empty (type_equality_entry_d, *worklist))
    {
      struct type_equality_entry entry;
      int added;

      entry = *VEC_last (type_equality_entry_d, *worklist);
      VEC_pop (type_equality_entry_d, *worklist);

      /* If the type pair has already been visited, we know it is
	 ok.  */
      bcache_full (&entry, sizeof (entry), cache, &added);
      if (!added)
	continue;

      if (check_types_equal (entry.type1, entry.type2, worklist) == Py_NE)
	return Py_NE;
    }

  return Py_EQ;
}

/* Implement the richcompare method.  */

static PyObject *
typy_richcompare (PyObject *self, PyObject *other, int op)
{
  int result = Py_NE;
  struct type *type1 = type_object_to_type (self);
  struct type *type2 = type_object_to_type (other);
  volatile struct gdb_exception except;

  /* We can only compare ourselves to another Type object, and only
     for equality or inequality.  */
  if (type2 == NULL || (op != Py_EQ && op != Py_NE))
    {
      Py_INCREF (Py_NotImplemented);
      return Py_NotImplemented;
    }

  if (type1 == type2)
    result = Py_EQ;
  else
    {
      struct bcache *cache;
      VEC (type_equality_entry_d) *worklist = NULL;
      struct type_equality_entry entry;

      cache = bcache_xmalloc (NULL, NULL);

      entry.type1 = type1;
      entry.type2 = type2;
      VEC_safe_push (type_equality_entry_d, worklist, &entry);

      TRY_CATCH (except, RETURN_MASK_ALL)
	{
	  result = check_types_worklist (&worklist, cache);
	}
      if (except.reason < 0)
	result = Py_NE;

      bcache_xfree (cache);
      VEC_free (type_equality_entry_d, worklist);
    }

  if (op == result)
    Py_RETURN_TRUE;
  Py_RETURN_FALSE;
}



static const struct objfile_data *typy_objfile_data_key;

static void
save_objfile_types (struct objfile *objfile, void *datum)
{
  type_object *obj = datum;
  htab_t copied_types;
  struct cleanup *cleanup;

  /* This prevents another thread from freeing the objects we're
     operating on.  */
  cleanup = ensure_python_env (get_objfile_arch (objfile), current_language);

  copied_types = create_copied_types_hash (objfile);

  while (obj)
    {
      type_object *next = obj->next;

      htab_empty (copied_types);

      obj->type = copy_type_recursive (objfile, obj->type, copied_types);

      obj->next = NULL;
      obj->prev = NULL;

      obj = next;
    }

  htab_delete (copied_types);

  do_cleanups (cleanup);
}

static void
set_type (type_object *obj, struct type *type)
{
  obj->type = type;
  obj->prev = NULL;
  if (type && TYPE_OBJFILE (type))
    {
      struct objfile *objfile = TYPE_OBJFILE (type);

      obj->next = objfile_data (objfile, typy_objfile_data_key);
      if (obj->next)
	obj->next->prev = obj;
      set_objfile_data (objfile, typy_objfile_data_key, obj);
    }
  else
    obj->next = NULL;
}

static void
typy_dealloc (PyObject *obj)
{
  type_object *type = (type_object *) obj;

  if (type->prev)
    type->prev->next = type->next;
  else if (type->type && TYPE_OBJFILE (type->type))
    {
      /* Must reset head of list.  */
      struct objfile *objfile = TYPE_OBJFILE (type->type);

      if (objfile)
	set_objfile_data (objfile, typy_objfile_data_key, type->next);
    }
  if (type->next)
    type->next->prev = type->prev;

  type->ob_type->tp_free (type);
}

/* Create a new Type referring to TYPE.  */
PyObject *
type_to_type_object (struct type *type)
{
  type_object *type_obj;

  type_obj = PyObject_New (type_object, &type_object_type);
  if (type_obj)
    set_type (type_obj, type);

  return (PyObject *) type_obj;
}

struct type *
type_object_to_type (PyObject *obj)
{
  if (! PyObject_TypeCheck (obj, &type_object_type))
    return NULL;
  return ((type_object *) obj)->type;
}



/* Implementation of gdb.lookup_type.  */
PyObject *
gdbpy_lookup_type (PyObject *self, PyObject *args, PyObject *kw)
{
  static char *keywords[] = { "name", "block", NULL };
  char *type_name = NULL;
  struct type *type = NULL;
  PyObject *block_obj = NULL;
  struct block *block = NULL;

  if (! PyArg_ParseTupleAndKeywords (args, kw, "s|O", keywords,
				     &type_name, &block_obj))
    return NULL;

  if (block_obj)
    {
      block = block_object_to_block (block_obj);
      if (! block)
	{
	  PyErr_SetString (PyExc_RuntimeError,
			   _("'block' argument must be a Block."));
	  return NULL;
	}
    }

  type = typy_lookup_typename (type_name, block);
  if (! type)
    return NULL;

  return (PyObject *) type_to_type_object (type);
}

void
gdbpy_initialize_types (void)
{
  int i;

  typy_objfile_data_key
    = register_objfile_data_with_cleanup (save_objfile_types, NULL);

  if (PyType_Ready (&type_object_type) < 0)
    return;
  if (PyType_Ready (&field_object_type) < 0)
    return;

  for (i = 0; pyty_codes[i].name; ++i)
    {
      if (PyModule_AddIntConstant (gdb_module,
				   /* Cast needed for Python 2.4.  */
				   (char *) pyty_codes[i].name,
				   pyty_codes[i].code) < 0)
	return;
    }

  Py_INCREF (&type_object_type);
  PyModule_AddObject (gdb_module, "Type", (PyObject *) &type_object_type);

  Py_INCREF (&field_object_type);
  PyModule_AddObject (gdb_module, "Field", (PyObject *) &field_object_type);
}



static PyGetSetDef type_object_getset[] =
{
  { "code", typy_get_code, NULL,
    "The code for this type.", NULL },
  { "sizeof", typy_get_sizeof, NULL,
    "The size of this type, in bytes.", NULL },
  { "tag", typy_get_tag, NULL,
    "The tag name for this type, or None.", NULL },
  { NULL }
};

static PyMethodDef type_object_methods[] =
{
  { "array", typy_array, METH_VARARGS,
    "array (N) -> Type\n\
Return a type which represents an array of N objects of this type." },
  { "const", typy_const, METH_NOARGS,
    "const () -> Type\n\
Return a const variant of this type." },
  { "fields", typy_fields, METH_NOARGS,
    "field () -> list\n\
Return a sequence holding all the fields of this type.\n\
Each field is a dictionary." },
  { "pointer", typy_pointer, METH_NOARGS,
    "pointer () -> Type\n\
Return a type of pointer to this type." },
  { "range", typy_range, METH_NOARGS,
    "range () -> tuple\n\
Return a tuple containing the lower and upper range for this type."},
  { "reference", typy_reference, METH_NOARGS,
    "reference () -> Type\n\
Return a type of reference to this type." },
  { "strip_typedefs", typy_strip_typedefs, METH_NOARGS,
    "strip_typedefs () -> Type\n\
Return a type formed by stripping this type of all typedefs."},
  { "target", typy_target, METH_NOARGS,
    "target () -> Type\n\
Return the target type of this type." },
  { "template_argument", typy_template_argument, METH_VARARGS,
    "template_argument (arg, [block]) -> Type\n\
Return the type of a template argument." },
  { "unqualified", typy_unqualified, METH_NOARGS,
    "unqualified () -> Type\n\
Return a variant of this type without const or volatile attributes." },
  { "volatile", typy_volatile, METH_NOARGS,
    "volatile () -> Type\n\
Return a volatile variant of this type" },
  { NULL }
};

static PyTypeObject type_object_type =
{
  PyObject_HEAD_INIT (NULL)
  0,				  /*ob_size*/
  "gdb.Type",			  /*tp_name*/
  sizeof (type_object),		  /*tp_basicsize*/
  0,				  /*tp_itemsize*/
  typy_dealloc,			  /*tp_dealloc*/
  0,				  /*tp_print*/
  0,				  /*tp_getattr*/
  0,				  /*tp_setattr*/
  0,				  /*tp_compare*/
  0,				  /*tp_repr*/
  0,				  /*tp_as_number*/
  0,				  /*tp_as_sequence*/
  0,				  /*tp_as_mapping*/
  0,				  /*tp_hash */
  0,				  /*tp_call*/
  typy_str,			  /*tp_str*/
  0,				  /*tp_getattro*/
  0,				  /*tp_setattro*/
  0,				  /*tp_as_buffer*/
  Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_ITER,  /*tp_flags*/
  "GDB type object",		  /* tp_doc */
  0,				  /* tp_traverse */
  0,				  /* tp_clear */
  typy_richcompare,		  /* tp_richcompare */
  0,				  /* tp_weaklistoffset */
  0,				  /* tp_iter */
  0,				  /* tp_iternext */
  type_object_methods,		  /* tp_methods */
  0,				  /* tp_members */
  type_object_getset,		  /* tp_getset */
  0,				  /* tp_base */
  0,				  /* tp_dict */
  0,				  /* tp_descr_get */
  0,				  /* tp_descr_set */
  0,				  /* tp_dictoffset */
  0,				  /* tp_init */
  0,				  /* tp_alloc */
  0,				  /* tp_new */
};

static PyTypeObject field_object_type =
{
  PyObject_HEAD_INIT (NULL)
  0,				  /*ob_size*/
  "gdb.Field",			  /*tp_name*/
  sizeof (field_object),	  /*tp_basicsize*/
  0,				  /*tp_itemsize*/
  field_dealloc,		  /*tp_dealloc*/
  0,				  /*tp_print*/
  0,				  /*tp_getattr*/
  0,				  /*tp_setattr*/
  0,				  /*tp_compare*/
  0,				  /*tp_repr*/
  0,				  /*tp_as_number*/
  0,				  /*tp_as_sequence*/
  0,				  /*tp_as_mapping*/
  0,				  /*tp_hash */
  0,				  /*tp_call*/
  0,				  /*tp_str*/
  0,				  /*tp_getattro*/
  0,				  /*tp_setattro*/
  0,				  /*tp_as_buffer*/
  Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_ITER,  /*tp_flags*/
  "GDB field object",		  /* tp_doc */
  0,				  /* tp_traverse */
  0,				  /* tp_clear */
  0,				  /* tp_richcompare */
  0,				  /* tp_weaklistoffset */
  0,				  /* tp_iter */
  0,				  /* tp_iternext */
  0,				  /* tp_methods */
  0,				  /* tp_members */
  0,				  /* tp_getset */
  0,				  /* tp_base */
  0,				  /* tp_dict */
  0,				  /* tp_descr_get */
  0,				  /* tp_descr_set */
  offsetof (field_object, dict),  /* tp_dictoffset */
  0,				  /* tp_init */
  0,				  /* tp_alloc */
  0,				  /* tp_new */
};