typerep.h

/*
 * Copyright (C) 1995-2008 University of Karlsruhe.  All right reserved.
 *
 * This file is part of libFirm.
 *
 * This file may be distributed and/or modified under the terms of the
 * GNU General Public License version 2 as published by the Free Software
 * Foundation and appearing in the file LICENSE.GPL included in the
 * packaging of this file.
 *
 * Licensees holding valid libFirm Professional Edition licenses may use
 * this file in accordance with the libFirm Commercial License.
 * Agreement provided with the Software.
 *
 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE.
 */

/**
 * @file
 * Declarations for functions and datastructures to represent types
 */
#ifndef FIRM_TYPEREP_H
#define FIRM_TYPEREP_H

#include "firm_types.h"

/**
 * @page entity       Entity representation
 *
 * An entity is the representation of program known objects in Firm.
 * The primary concept of entities is to represent members of complex
 * types, i.e., fields and methods of classes.  As not all programming
 * language model all variables and methods as members of some class,
 * the concept of entities is extended to cover also local and global
 * variables, and arbitrary procedures.
 *
 * An entity always specifies the type of the object it represents and
 * the type of the object it is a part of, the owner of the entity.
 * Originally this is the type of the class of which the entity is a
 * member.
 * The owner of local variables is the procedure they are defined in.
 * The owner of global variables and procedures visible in the whole
 * program is a universally defined class type "GlobalType".  The owner
 * of procedures defined in the scope of an other procedure is the
 * enclosing procedure.
 *
 * The type ir_entity is an abstract data type to represent program entities.
 * If contains the following attributes:
 *
 *   - owner:      A compound type this entity is a part of.
 *   - type:       The type of this entity.
 *   - name:       The string that represents this entity in the source program.
 *   - allocation: A flag saying whether the entity is dynamically or statically
 *                 allocated (values: dynamic_allocated,  static_allocated,
 *                 automatic_allocated).
 *   - visibility: A flag indicating the visibility of this entity (values: local,
 *                 external_visible,  external_allocated)
 *   - variability: A flag indicating the variability of this entity (values:
 *                  uninitialized, initialized, part_constant, constant)
 *   - volatility: @@@
 *   - offset:     The offset of the entity within the compound object in bytes.  Only set
 *                 if the owner in the state "layout_fixed".
 *   - offset_bits_remainder:   The offset bit remainder of a bitfield entity (in a compound)
 *                 in bits.  Only set if the owner in the state "layout_fixed".
 *   - overwrites: A list of entities overwritten by this entity.  This list is only
 *                 existent if the owner of this entity is a class.  The members in
 *                 this list must be entities of super classes.
 *   - overwrittenby: A list of entities that overwrite this entity.  This list is only
 *                 existent if the owner of this entity is a class.  The members in
 *                 this list must be entities of sub classes.
 *   - link:       A void* to associate some additional information with the entity.
 *   - irg:        If the entity is a method this is the ir graph that represents the
 *                 code of the method.
 *   - peculiarity: The peculiarity of the entity.  If the entity is a method this
 *                 indicates whether the entity represents
 *                 a real method or whether it only exists to describe an interface.
 *                 In that case there nowhere exists code for this entity and this entity
 *                 is never dynamically used in the code.
 *                 Values: description, existent.  Default: existent.
 *   - visited:    visited flag.  Master flag is type_visited.
 *
 * These fields can only be accessed via access functions.
 *
 * @see  ir_type, ir_entity
 */

/** This enumeration flags the visibility of entities and types.
 *
 * This is necessary for partial compilation.
 * We rely on the ordering of the flags.
 */
typedef enum {
	visibility_local,              /**< The entity is only visible locally.  This is the default for
	                                    entities.
	                                    The type is only visible locally.  All instances are allocated
	                                    locally, and no pointer to entities of this type are passed
	                                    out of this compilation unit. */
	visibility_external_visible,   /**< The entity is visible to other external program parts, but
	                                    it is defined here.  It may not be optimized away.  The entity must
	                                    be static_allocated.
	                                    For types:  entities of this type can be accessed externally.  No
	                                    instances of this type are allocated externally.  */
	visibility_external_allocated  /**< The entity is defined and allocated externally.  This compilation
	                                    must not allocate memory for this entity. The entity must
	                                    be static_allocated.  This can also be an external defined
	                                    method.
	                                    For types:  entities of this type are allocated and accessed from
	                                    external code.  Default for types.  */
} ir_visibility;

/** This enumeration flags the peculiarity of entities and types. */
typedef enum {
	peculiarity_description,     /**< Represents only a description.  The entity/type is never
	                          allocated, no code/data exists for this entity/type.
	                      @@@ eventually rename to descriptive (adjective as the others!)*/
	peculiarity_inherited,       /**< Describes explicitly that other entities are
	                          inherited to the owner of this entity.
	                          Overwrites must refer to at least one other
	                          entity.  If this is a method entity there exists
	                          no irg for this entity, only for one of the
	                          overwritten ones.
	                      Only for entity. */
	peculiarity_existent         /**< The entity/type (can) exist.
	                  @@@ eventually rename to 'real' i.e., 'echt'
	                      This serves better as opposition to description _and_ inherited.*/
} ir_peculiarity;

/**
 * Creates a new entity.
 *
 * Automatically inserts the entity as a member of owner.
 * Entity is automatic_allocated and uninitialized except if the type
 * is type_method, then it is static_allocated and constant.  The constant
 * value is a pointer to the method.
 * Visibility is local, offset -1, and it is not volatile.
 */
ir_entity *new_entity(ir_type *owner, ident *name, ir_type *tp);

/**
 * Creates a new entity.
 *
 * Automatically inserts the entity as a member of owner.
 * The entity is automatic allocated and uninitialized except if the type
 * is type_method, then it is static allocated and constant.  The constant
 * value is a pointer to the method.
 * Visibility is local, offset -1, and it is not volatile.
 */
ir_entity *new_d_entity(ir_type *owner, ident *name, ir_type *tp, dbg_info *db);

/**
 * Copies the entity if the new_owner is different from the
 * owner of the old entity,  else returns the old entity.
 *
 * Automatically inserts the new entity as a member of owner.
 * Resets the overwrites/overwritten_by fields.
 * Keeps the old atomic value.
 *   @@@ Maybe we should change this.  If peculiarity of a method
 *       is existent, we should add a new SymConst that points to
 *       itself and not to the origin.  Right now we have to change
 *       the peculiarity and then set a new atomic value by hand.
 */
ir_entity *copy_entity_own(ir_entity *old, ir_type *new_owner);

/**
 * Copies the entity if the new_name is different from the
 * name of the old entity, else returns the old entity.
 *
 * Automatically inserts the new entity as a member of owner.
 * The mangled name ld_name is set to NULL.
 * Overwrites relation is copied from old.
 */
ir_entity *copy_entity_name(ir_entity *old, ident *new_name);

/**
 * Frees the entity.
 *
 * The owner will still contain the pointer to this
 * entity, as well as all other references!
 */
void free_entity(ir_entity *ent);

/** Returns the name of an entity. */
const char *get_entity_name(const ir_entity *ent);

/** Returns the ident of an entity. */
ident *get_entity_ident(const ir_entity *ent);

/** Sets the ident of the entity. */
void set_entity_ident(ir_entity *ent, ident *id);

/** Returns the mangled name of the entity.
 *
 * If the mangled name is set it returns the existing name.
 * Else it generates a name with mangle_entity()
 * and remembers this new name internally.
 */
ident *get_entity_ld_ident(ir_entity *ent);

/** Sets the mangled name of the entity. */
void set_entity_ld_ident(ir_entity *ent, ident *ld_ident);

/** Returns the mangled name of the entity as a string. */
const char *get_entity_ld_name(ir_entity *ent);

/** Returns the owner of the entity. */
ir_type *get_entity_owner(ir_entity *ent);

/** Sets the owner field in entity to owner.  Don't forget to add
   ent to owner!! */
void set_entity_owner(ir_entity *ent, ir_type *owner);

/** Returns the type of an entity. */
ir_type *get_entity_type(ir_entity *ent);

/** Sets the type of an entity. */
void set_entity_type(ir_entity *ent, ir_type *tp);

/** The allocation type. */
typedef enum {
	allocation_automatic, /**< The entity is allocated during runtime, implicitly
	                           as component of a compound type.   This is the default. */
	allocation_parameter, /**< The entity is a parameter.  It is also automatic allocated.
	                           We distinguish the allocation of parameters from the allocation
	                           of local variables as their placement depends on the calling
	                           conventions. */
	allocation_dynamic,   /**< The entity is allocated during runtime, explicitly
	                           by an Alloc node. */
	allocation_static     /**< The entity is allocated statically.  We can use a
	                           Const as address of the entity.  This is the default for methods. */
} ir_allocation;

/** Returns the allocation type of an entity. */
ir_allocation get_entity_allocation(const ir_entity *ent);

/** Sets the allocation type of an entity. */
void set_entity_allocation(ir_entity *ent, ir_allocation al);

/** Return the name of the allocation type. */
const char *get_allocation_name(ir_allocation al);

/** Returns the visibility of an entity. */
ir_visibility get_entity_visibility(const ir_entity *ent);

/** Sets the visibility of an entity. */
void set_entity_visibility(ir_entity *ent, ir_visibility vis);

/** Return the name of the visibility */
const char *get_visibility_name(ir_visibility vis);

/** This enumeration flags the variability of entities. */
typedef enum {
	variability_uninitialized,    /**< The content of the entity is completely unknown. Default. */
	variability_initialized,      /**< After allocation the entity is initialized with the
	                                   value given somewhere in the entity. */
	variability_part_constant,    /**< For entities of compound types.
	                                   The members of the entity are mixed constant,
	                                   initialized or uninitialized. */
	variability_constant          /**< The entity is constant. */
} ir_variability;

/** Returns the variability of an entity. */
ir_variability get_entity_variability(const ir_entity *ent);

/** Sets the variability of an entity. */
void set_entity_variability(ir_entity *ent, ir_variability var);

/** Return the name of the variability. */
const char *get_variability_name(ir_variability var);

/** This enumeration flags the volatility of entities and Loads/Stores. */
typedef enum {
	volatility_non_volatile,    /**< The entity is not volatile. Default. */
	volatility_is_volatile      /**< The entity is volatile. */
} ir_volatility;

/** Returns the volatility of an entity. */
ir_volatility get_entity_volatility(const ir_entity *ent);

/** Sets the volatility of an entity. */
void set_entity_volatility(ir_entity *ent, ir_volatility vol);

/** Return the name of the volatility. */
const char *get_volatility_name(ir_volatility var);

/** Returns alignment of entity in bytes */
unsigned get_entity_alignment(const ir_entity *entity);

/** Sets alignment for entity in bytes */
void set_entity_alignment(ir_entity *entity, unsigned alignment);

/** This enumeration flags the align of Loads/Stores. */
typedef enum {
	align_non_aligned,    /**< The entity is not aligned. */
	align_is_aligned      /**< The entity is aligned. Default */
} ir_align;

/** Returns indication wether entity is aligned in memory. */
ir_align get_entity_aligned(const ir_entity *ent);

/** Sets indication wether entity is aligned in memory */
void set_entity_aligned(ir_entity *ent, ir_align a);

/** Return the name of the alignment. */
const char *get_align_name(ir_align a);

/** This enumeration flags the stickyness of an entity. */
typedef enum {
	stickyness_unsticky,  /**< The entity can be removed from
	                           the program, unless contraindicated
	                           by other attributes. Default. */
	stickyness_sticky     /**< The entity must remain in the
	                           program in any case. There might be external
	                           callers. */
} ir_stickyness;

/** Get the entity's stickyness. */
ir_stickyness get_entity_stickyness(const ir_entity *ent);

/** Set the entity's stickyness. */
void set_entity_stickyness(ir_entity *ent, ir_stickyness stickyness);

/** Returns the offset of an entity (in a compound) in bytes. Only set if layout = fixed. */
int get_entity_offset(const ir_entity *ent);

/** Sets the offset of an entity (in a compound) in bytes. */
void set_entity_offset(ir_entity *ent, int offset);

/** Returns the offset bit remainder of a bitfield entity (in a compound) in bits. Only set if layout = fixed. */
unsigned char get_entity_offset_bits_remainder(const ir_entity *ent);

/** Sets the offset bit remainder of a bitfield entity (in a compound) in bits. */
void set_entity_offset_bits_remainder(ir_entity *ent, unsigned char offset);

/** Returns the stored intermediate information. */
void *get_entity_link(const ir_entity *ent);

/** Stores new intermediate information. */
void set_entity_link(ir_entity *ent, void *l);

/* -- Fields of method entities -- */
/** The entity knows the corresponding irg if the entity is a method.
   This allows to get from a Call to the called irg.
   Only entities of peculiarity "existent" can have a corresponding irg,
   else the field is fixed to NULL.  (Get returns NULL, set asserts.) */
ir_graph *get_entity_irg(const ir_entity *ent);
void set_entity_irg(ir_entity *ent, ir_graph *irg);

/** Gets the entity vtable number. */
unsigned get_entity_vtable_number(const ir_entity *ent);

/** Sets the entity vtable number. */
void set_entity_vtable_number(ir_entity *ent, unsigned vtable_number);

/** Return the peculiarity of an entity. */
ir_peculiarity get_entity_peculiarity(const ir_entity *ent);

/** Sets the peculiarity of an entity. */
void set_entity_peculiarity(ir_entity *ent, ir_peculiarity pec);

/** Checks if an entity cannot be overridden anymore. */
int is_entity_final(const ir_entity *ent);

/** Sets/resets the final flag of an entity. */
void set_entity_final(ir_entity *ent, int final);

/** Set label number of an entity with code type */
void set_entity_label(ir_entity *ent, ir_label_t label);
/** Return label number of an entity with code type */
ir_label_t get_entity_label(const ir_entity *ent);

/** Checks if an entity is compiler generated. */
int is_entity_compiler_generated(const ir_entity *ent);

/** Sets/resets the compiler generated flag. */
void set_entity_compiler_generated(ir_entity *ent, int flag);

/** Checks if an entity is marked by the backend. */
int is_entity_backend_marked(const ir_entity *ent);

/** Sets/resets the backend marker flag. */
void set_entity_backend_marked(ir_entity *ent, int flag);

/**
 * Bitfield type indicating the way an entity is used.
 */
typedef enum {
	ir_usage_none             = 0,      /**< This entity is unused. */
	ir_usage_address_taken    = 1 << 0, /**< The address of this entity was taken. */
	ir_usage_write            = 1 << 1, /**< The entity was written to. */
	ir_usage_read             = 1 << 2, /**< The entity was read. */
	ir_usage_reinterpret_cast = 1 << 3, /**< The entity was read but with a wrong mode
	                                         (an implicit reinterpret cast) */
	/** Unknown access */
	ir_usage_unknown
		= ir_usage_address_taken | ir_usage_write | ir_usage_read
		| ir_usage_reinterpret_cast
} ir_entity_usage;

/** Return the entity usage */
ir_entity_usage get_entity_usage(const ir_entity *ent);

/** Sets/resets the state of the address taken flag of an entity. */
void set_entity_usage(ir_entity *ent, ir_entity_usage flag);

/**
 * Returns the debug information of an entity.
 *
 * @param ent The entity.
 */
dbg_info *get_entity_dbg_info(const ir_entity *ent);

/**
 * Sets the debug information of an entity.
 *
 * @param ent The entity.
 * @param db  The debug info.
 */
void set_entity_dbg_info(ir_entity *ent, dbg_info *db);

/* -- Representation of constant values of entities -- */
/**
 * Returns true if the the node is representable as code on
 * const_code_irg.
 *
 * @deprecated This function is not used by libFirm and stays here
 *             only as a helper for the old Jack frontend.
 */
int is_irn_const_expression(ir_node *n);

/**
 * Copies a Firm subgraph that complies to the restrictions for
 * constant expressions to current_block in current_ir_graph.
 *
 * @param dbg  debug info for all newly created nodes
 * @param n    the node
 *
 * Set current_ir_graph to get_const_code_irg() to generate a constant
 * expression.
 */
ir_node *copy_const_value(dbg_info *dbg, ir_node *n);

/* Set has no effect for existent entities of type method. */
ir_node *get_atomic_ent_value(ir_entity *ent);
void set_atomic_ent_value(ir_entity *ent, ir_node *val);

/** the kind (type) of an initializer */
typedef enum ir_initializer_kind_t {
	/** initializer containing an ir_node from the const-code irg */
	IR_INITIALIZER_CONST,
	/** initializer containing a tarval */
	IR_INITIALIZER_TARVAL,
	/** initializes type with default values (usually 0) */
	IR_INITIALIZER_NULL,
	/** list of initializers used to initializer a compound or array type */
	IR_INITIALIZER_COMPOUND
} ir_initializer_kind_t;

/** returns kind of an initializer */
ir_initializer_kind_t get_initializer_kind(const ir_initializer_t *initializer);

/** Return the name of the initializer kind. */
const char *get_initializer_kind_name(ir_initializer_kind_t ini);

/**
 * returns the null initializer (there's only one instance of it in a program )
 */
ir_initializer_t *get_initializer_null(void);

/**
 * creates an initializer containing a reference to a node on the const-code
 * irg.
 */
ir_initializer_t *create_initializer_const(ir_node *value);

/** creates an initializer containing a single tarval value */
ir_initializer_t *create_initializer_tarval(tarval *tv);

/** return value contained in a const initializer */
ir_node *get_initializer_const_value(const ir_initializer_t *initializer);

/** return value contained in a tarval initializer */
tarval *get_initializer_tarval_value(const ir_initializer_t *initialzier);

/** creates a compound initializer which holds @p n_entries entries */
ir_initializer_t *create_initializer_compound(unsigned n_entries);

/** returns the number of entries in a compound initializer */
unsigned get_initializer_compound_n_entries(const ir_initializer_t *initializer);

/** sets entry with index @p index to the initializer @p value */
void set_initializer_compound_value(ir_initializer_t *initializer,
                                    unsigned index, ir_initializer_t *value);

/** returns the value with index @p index of a compound initializer */
ir_initializer_t *get_initializer_compound_value(
		const ir_initializer_t *initializer, unsigned index);

/** Creates a new compound graph path of given length. */
compound_graph_path *new_compound_graph_path(ir_type *tp, int length);

/** Returns non-zero if an object is a compound graph path */
int is_compound_graph_path(const void *thing);

/** Frees a graph path object */
void free_compound_graph_path(compound_graph_path *gr);

/** Returns the length of a graph path */
int get_compound_graph_path_length(const compound_graph_path *gr);

/** Get the entity node of an compound graph path at position pos. */
ir_entity *get_compound_graph_path_node(const compound_graph_path *gr, int pos);
/** Set the entity node of an compound graph path at position pos. */
void      set_compound_graph_path_node(compound_graph_path *gr, int pos, ir_entity *node);
/** Get the index of an compound graph path at position pos. */
int       get_compound_graph_path_array_index(const compound_graph_path *gr, int pos);
/** Set the index of an compound graph path at position pos. */
void      set_compound_graph_path_array_index(compound_graph_path *gr, int pos, int index);
/** Get the type of an compound graph path. */
ir_type   *get_compound_graph_path_type(const compound_graph_path *gr);

/** Checks whether the path up to pos is correct. If the path contains a NULL,
 *  assumes the path is not complete and returns non-zero. */
int is_proper_compound_graph_path(compound_graph_path *gr, int pos);

/* A value of a compound entity is a pair of a value and the description of the
   corresponding access path to the member of the compound.  */
void add_compound_ent_value_w_path(ir_entity *ent, ir_node *val, compound_graph_path *path);
void set_compound_ent_value_w_path(ir_entity *ent, ir_node *val, compound_graph_path *path, int pos);

/** Returns the number of constant values needed to initialize the entity.
 *
 *  Asserts if the entity has variability_uninitialized.
 * */
int get_compound_ent_n_values(ir_entity *ent);
/** Returns a constant value given the position. */
ir_node *get_compound_ent_value(ir_entity *ent, int pos);
/** Returns the access path for value at position pos. */
compound_graph_path *get_compound_ent_value_path(ir_entity *ent, int pos);
/** Returns a constant value given the access path.
 *  The path must contain array indices for all array element entities. */
ir_node *get_compound_ent_value_by_path(ir_entity *ent, compound_graph_path *path);

/** Removes all constant entries where the path ends at value_ent. Does not
   free the memory of the paths.  (The same path might be used for several
   constant entities. */
void remove_compound_ent_value(ir_entity *ent, ir_entity *value_ent);

/* Some languages support only trivial access paths, i.e., the member is a
   direct, atomic member of the constant entities type. In this case the
   corresponding entity can be accessed directly.  The following functions
   allow direct access. */

/** Generates a Path with length 1.
    Beware: Has a bad runtime for array elements (O(|array|) and should be
    avoided there. Use add_compound_ent_value_w_path() instead and create
    the path manually. */
void add_compound_ent_value(ir_entity *ent, ir_node *val, ir_entity *member);

/** Returns the last member in the path */
ir_entity *get_compound_ent_value_member(ir_entity *ent, int pos);

/** Sets the path at pos 0 */
void set_compound_ent_value(ir_entity *ent, ir_node *val, ir_entity *member, int pos);

/** Sets the new style initializers of an entity. */
void set_entity_initializer(ir_entity *entity, ir_initializer_t *initializer);

/** Returns true, if an entity has new style initializers. */
int has_entity_initializer(const ir_entity *entity);

/** Return the new style initializers of an entity. */
ir_initializer_t *get_entity_initializer(const ir_entity *entity);

/** Initializes the entity ent which must be of a one dimensional
   array type with the values given in the values array.
   The array must have a lower and an upper bound.  Keeps the
   order of values. Does not test whether the number of values
   fits into the given array size.  Does not test whether the
   values have the proper mode for the array. */
void set_array_entity_values(ir_entity *ent, tarval **values, int num_vals);

/**
 * Return the offset in bits from the last byte address.
 *
 * This requires that the layout of all concerned types is fixed.
 *
 * @param ent Any entity of compound type with at least pos initialization values.
 * @param pos The position of the value for which the offset is requested.
 */
unsigned get_compound_ent_value_offset_bit_remainder(ir_entity *ent, int pos);

/** Return the overall offset of value at position pos in bytes.
 *
 * This requires that the layout of all concerned types is fixed.
 * Asserts if bit offset is not byte aligned.
 *
 * @param ent Any entity of compound type with at least pos initialization values.
 * @param pos The position of the value for which the offset is requested.
 */
unsigned get_compound_ent_value_offset_bytes(ir_entity *ent, int pos);

/* --- Fields of entities with a class type as owner --- */
/* Overwrites is a field that specifies that an access to the overwritten
   entity in the supertype must use this entity.  It's a list as with
   multiple inheritance several entities can be overwritten.  This field
   is mostly useful for method entities.
   If a Sel node selects an entity that is overwritten by other entities it
   must return a pointer to the entity of the dynamic type of the pointer
   that is passed to it.  Lowering of the Sel node must assure this.
   Overwrittenby is the inverse of overwrites.  Both add routines add
   both relations, they only differ in the order of arguments. */
void add_entity_overwrites(ir_entity *ent, ir_entity *overwritten);
int get_entity_n_overwrites(ir_entity *ent);
int get_entity_overwrites_index(ir_entity *ent, ir_entity *overwritten);
ir_entity *get_entity_overwrites(ir_entity *ent, int pos);
void set_entity_overwrites(ir_entity *ent, int pos, ir_entity *overwritten);
void remove_entity_overwrites(ir_entity *ent, ir_entity *overwritten);

void add_entity_overwrittenby(ir_entity *ent, ir_entity *overwrites);
int get_entity_n_overwrittenby(ir_entity *ent);
int get_entity_overwrittenby_index(ir_entity *ent, ir_entity *overwrites);
ir_entity *get_entity_overwrittenby(ir_entity *ent, int pos);
void set_entity_overwrittenby(ir_entity *ent, int pos, ir_entity *overwrites);
void remove_entity_overwrittenby(ir_entity *ent, ir_entity *overwrites);

/**
 *   Checks whether a pointer points to an entity.
 *
 *   @param thing     an arbitrary pointer
 *
 *   @return
 *       true if the thing is an entity, else false
 */
int is_entity(const void *thing);

/** Returns true if the type of the entity is a primitive, pointer
 * enumeration or method type.
 *
 * @note This is a different classification than from is_primitive_type().
 */
int is_atomic_entity(ir_entity *ent);
/** Returns true if the type of the entity is a class, structure,
   array or union type. */
int is_compound_entity(ir_entity *ent);
/** Returns true if the type of the entity is a Method type. */
int is_method_entity(ir_entity *ent);

/** Returns non-zero if ent1 and ent2 have are equal except for their owner.
   Two entities are equal if
    - they have the same type (the same C-struct)
    - ...?
*/
int equal_entity(ir_entity *ent1, ir_entity *ent2);

/** Outputs a unique number for this entity if libfirm is compiled for
 *  debugging, (configure with --enable-debug) else returns the address
 *  of the type cast to long.
 */
long get_entity_nr(const ir_entity *ent);

/** Returns the entities visited count. */
ir_visited_t get_entity_visited(ir_entity *ent);

/** Sets the entities visited count. */
void set_entity_visited(ir_entity *ent, ir_visited_t num);

/** Sets visited field in entity to entity_visited. */
void mark_entity_visited(ir_entity *ent);

/** Returns true if this entity was visited. */
int entity_visited(ir_entity *ent);

/** Returns true if this entity was not visited. */
int entity_not_visited(ir_entity *ent);

/**
 * Returns the mask of the additional entity properties.
 * The properties are automatically inherited from the irg if available
 * or from the method type if they were not set using
 * set_entity_additional_properties() or
 * set_entity_additional_property().
 */
unsigned get_entity_additional_properties(ir_entity *ent);

/** Sets the mask of the additional graph properties. */
void set_entity_additional_properties(ir_entity *ent, unsigned property_mask);

/** Sets one additional graph property. */
void set_entity_additional_property(ir_entity *ent, mtp_additional_property flag);

/** Returns the class type that this type info entity represents or NULL
    if ent is no type info entity. */
ir_type *get_entity_repr_class(const ir_entity *ent);

/**
 * @page unknown_entity  The Unknown entity
 *
 *  This entity is an auxiliary entity dedicated to support analyses.
 *
 *  The unknown entity represents that there could be an entity, but it is not
 *  known.  This entity can be used to initialize fields before an analysis (not known
 *  yet) or to represent the top of a lattice (could not be determined).  There exists
 *  exactly one entity unknown. This entity has as owner and as type the unknown type. It is
 *  allocated when initializing the entity module.
 *
 *  The entity can take the role of any entity, also methods.  It returns default
 *  values in these cases.
 *
 *  The following values are set:
 *
 * - name          = "unknown_entity"
 * - ld_name       = "unknown_entity"
 * - owner         = unknown_type
 * - type          = unknown_type
 * - allocation    = allocation_automatic
 * - visibility    = visibility_external_allocated
 * - offset        = -1
 * - variability   = variability_uninitialized
 * - value         = SymConst(unknown_entity)
 * - values        = NULL
 * - val_paths     = NULL
 * - peculiarity   = peculiarity_existent
 * - volatility    = volatility_non_volatile
 * - stickyness    = stickyness_unsticky
 * - ld_name       = NULL
 * - overwrites    = NULL
 * - overwrittenby = NULL
 * - irg           = NULL
 * - link          = NULL
 */
/* A variable that contains the only unknown entity. */
extern ir_entity *unknown_entity;

/** Returns the @link unknown_entity unknown entity @endlink. */
ir_entity *get_unknown_entity(void);

/** Encodes how a pointer parameter is accessed. */
typedef enum acc_bits {
	ptr_access_none  = 0,                                 /**< no access */
	ptr_access_read  = 1,                                 /**< read access */
	ptr_access_write = 2,                                 /**< write access */
	ptr_access_rw    = ptr_access_read|ptr_access_write,  /**< read AND write access */
	ptr_access_store = 4,                                 /**< the pointer is stored */
	ptr_access_all   = ptr_access_rw|ptr_access_store     /**< all possible access */
} ptr_access_kind;

#define IS_READ(a)     ((a) & ptr_access_read)
#define IS_WRITTEN(a)  ((a) & ptr_access_write)
#define IS_STORED(a)   ((a) & ptr_access_store)

/**
 * @page tyop  type operations
 *  This module specifies the kinds of types available in firm.
 *
 *  They are called type opcodes. These include classes, structs, methods, unions,
 *  arrays, enumerations, pointers and primitive types.
 *  Special types with own opcodes are the id type, a type representing an unknown
 *  type and a type used to specify that something has no type.
 *
 *  @see type.h
 */

/**
 *  An enum for the type kinds.
 *  For each type kind exists a typecode to identify it.
 */
typedef enum {
	tpo_uninitialized = 0,   /* not a type opcode */
	tpo_class,               /**< A class type. */
	tpo_struct,              /**< A struct type. */
	tpo_method,              /**< A method type. */
	tpo_union,               /**< An union type. */
	tpo_array,               /**< An array type. */
	tpo_enumeration,         /**< An enumeration type. */
	tpo_pointer,             /**< A pointer type. */
	tpo_primitive,           /**< A primitive type. */
	tpo_id,                  /**< Special Id tag used for type replacement. */
	tpo_code,                /**< a piece of code (a basic block) */
	tpo_none,                /**< Special type for the None type. */
	tpo_unknown,             /**< Special code for the Unknown type. */
	tpo_max                  /* not a type opcode */
} tp_opcode;

/**
 * A structure containing information about a kind of type.
 * A structure containing information about a kind of type.  So far
 * this is only the kind name, an enum for case-switching and some
 * internal values.
 *
 * @see  get_tpop_name(), get_tpop_code(), get_tpop_ident()
 */
typedef struct tp_op tp_op;


/**
 * Returns the string for the type opcode.
 *
 * @param op  The type opcode to get the string from.
 * @return a string.  (@todo Null terminated?)
 */
const char *get_tpop_name(const tp_op *op);

/**
 * Returns an enum for the type opcode.
 *
 * @param op   The type opcode to get the enum from.
 * @return the enum.
 */
tp_opcode get_tpop_code(const tp_op *op);

/**
 * Returns the ident for the type opcode.
 *
 * @param op   The type opcode to get the ident from.
 * @return The ident.
 */
ident *get_tpop_ident(const tp_op *op);

/**
 * This type opcode marks that the corresponding type is a class type.
 *
 * Consequently the type refers to supertypes, subtypes and entities.
 * Entities can be any fields, but also methods.
 * @@@ value class or not???
 * This struct is dynamically allocated but constant for the lifetime
 * of the library.
 */
extern const tp_op *type_class;
const tp_op *get_tpop_class(void);

/**
 * This type opcode marks that the corresponding type is a compound type
 * as a struct in C.
 *
 * Consequently the type refers to a list of entities
 * which may not be methods (but pointers to methods).
 * This struct is dynamically allocated but constant for the lifetime
 * of the library.
 */
extern const tp_op *type_struct;
const tp_op *get_tpop_struct(void);

/**
 * This type opcode marks that the corresponding type is a method type.
 *
 * Consequently it refers to a list of arguments and results.
 * This struct is dynamically allocated but constant for the lifetime
 * of the library.
 */
extern const tp_op *type_method;
const tp_op *get_tpop_method(void);

/**
 * This type opcode marks that the corresponding type is a union type.
 *
 * Consequently it refers to a list of unioned types.
 * This struct is dynamically allocated but constant for the lifetime
 * of the library.
 */
extern const tp_op *type_union;
const tp_op *get_tpop_union(void);

/**
 * This type opcode marks that the corresponding type is an array type.
 *
 * Consequently it contains a list of dimensions (lower and upper bounds)
 * and an element type.
 * This struct is dynamically allocated but constant for the lifetime
 * of the library.
 */
extern const tp_op *type_array;
const tp_op *get_tpop_array(void);

/**
 * This type opcode marks that the corresponding type is an enumeration type.
 *
 * Consequently it contains a list of idents for the enumeration identifiers
 * and a list of target values that are the constants used to implement
 * the enumerators.
 * This struct is dynamically allocated but constant for the lifetime
 * of the library.
 */
extern const tp_op *type_enumeration;
const tp_op *get_tpop_enumeration(void);

/**
 * This type opcode marks that the corresponding type is a pointer type.
 *
 * It contains a reference to the type the pointer points to.
 * This struct is dynamically allocated but constant for the lifetime
 * of the library.
 */
extern const tp_op *type_pointer;
const tp_op *get_tpop_pointer(void);

/**
 * This type opcode marks that the corresponding type is a primitive type.
 *
 * Primitive types are types that are directly mapped to target machine
 * modes.
 * This struct is dynamically allocated but constant for the lifetime
 * of the library.
 */
extern const tp_op *type_primitive;
const tp_op *get_tpop_primitive(void);

/**
 * This type opcode is an auxiliary opcode dedicated to support transformations
 * of the type structure.
 *
 * If a type is changed to another type with another
 * opcode the new type will be allocated with new memory.  All nodes refering
 * to the old type need to be changed to refer to the new one.  This is simplified
 * by turning the old type into an id type that merely forwards to the new type
 * that now replaces the old one.
 * type_ids should never be visible out of the type module.  All access routines
 * should automatically check for type_id and eventually follow the forward in
 * type_id.  Two types are exchanged by a call to exchange_types.
 * If a type_id is visible externally report this as bug.  If it is assured that
 * this never happens this extern variable can be moved to tpop_t.h.
 * This struct is dynamically allocated but constant for the lifetime
 * of the library.
 */
extern const tp_op *type_id;
const tp_op *get_tpop_id(void);

/**
 * The code type is used to mark pieces of code (basic blocks)
 */
extern const tp_op *tpop_code;
const tp_op *get_tpop_code_type(void);

/**
 * This type opcode is an auxiliary opcode dedicated to support type analyses.
 *
 * Types with this opcode represents that there is no type.
 * The type can be used to initialize fields of the type* that actually can not
 * contain a type or that are initialized for an analysis. There exists exactly
 * one type with this opcode.
 */
extern const tp_op *tpop_none;
const tp_op *get_tpop_none(void);

/**
 * This type opcode is an auxiliary opcode dedicated to support type analyses.
 *
 * Types with this opcode represents that there could be a type, but it is not
 * known.  This type can be used to initialize fields before an analysis (not known
 * yet) or to represent the top of a lattice (could not be determined).  There exists
 * exactly one type with this opcode.
 */
extern const tp_op *tpop_unknown;
const tp_op *get_tpop_unknown(void);

/* ----------------------------------------------------------------------- */
/* Classify pairs of types/entities in the inheritance relations.          */
/* ----------------------------------------------------------------------- */

/** Returns true if low is subclass of high.
 *
 *  Low is a subclass of high if low == high or if low is a subclass of
 *  a subclass of high.  I.e, we search in all subtypes of high for low.
 *  @@@ this can be implemented more efficient if we know the set of all
 *  subclasses of high.  */
int is_SubClass_of(ir_type *low, ir_type *high);

/** Subclass check for pointers to classes.
 *
 *  Dereferences at both types the same amount of pointer types (as
 *  many as possible).  If the remaining types are both class types
 *  and subclasses, returns true, else false.  Can also be called with
 *  two class types.  */
int is_SubClass_ptr_of(ir_type *low, ir_type *high);

/** Returns true if high is superclass of low.
 *
 *  Low is a subclass of high if low == high or if low is a subclass of
 *  a subclass of high.  I.e, we search in all subtypes of high for low.
 *  @@@ this can be implemented more efficient if we know the set of all
 *  subclasses of high.  */
#define is_SuperClass_of(high, low) is_SubClass_of(low, high)

/** Superclass check for pointers to classes.
 *
 *  Dereferences at both types the same amount of pointer types (as
 *  many as possible).  If the remaining types are both class types
 *  and superclasses, returns true, else false.  Can also be called with
 *  two class types.  */
#define is_SuperClass_ptr_of(low, high) is_SubClass_ptr_of(high, low)

/** Returns true if high is (transitive) overwritten by low.
 *
 *  Returns false if high == low. */
int is_overwritten_by(ir_entity *high, ir_entity *low);

/** Resolve polymorphism in the inheritance relation.
 *
 *  Returns the dynamically referenced entity if the static entity and the
 *  dynamic type are given.
 *  Searches downwards in overwritten tree. */
ir_entity *resolve_ent_polymorphy(ir_type *dynamic_class, ir_entity* static_ent);

/* ----------------------------------------------------------------------- */
/* Resolve implicit inheritance.                                           */
/* ----------------------------------------------------------------------- */

/** Default name mangling for inherited entities.
 *
 *  Returns an ident that consists of the name of type followed by an
 *  underscore and the name (not ld_name) of the entity. */
ident *default_mangle_inherited_name(const ir_entity *ent, const ir_type *clss);

/** Type of argument functions for inheritance resolver.
 *
 * @param ent     The entity in the super type that will be overwritten
 *                by the newly generated entity, for which this name is
 *                used.
 * @param clss    The class type in which the new entity will be placed.
 */
typedef ident *mangle_inherited_name_func(const ir_entity *ent, const ir_type *clss);

/** Resolve implicit inheritance.
 *
 *  Resolves the implicit inheritance supplied by firm.  Firm defines,
 *  that each entity that is not overwritten in a subclass is
 *  inherited to this subclass without change implicitly.  This
 *  function generates entities that explicitly represent this
 *  inheritance.  It generates for each entity overwriting entities in
 *  all subclasses of the owner of the entity, if the entity is not
 *  overwritten in that subclass.
 *
 *  The name of the new entity is generated with the function passed.
 *  If the function is NULL, the default_mangle_inherited_name() is
 *  used.
 *
 *  This function was moved here from firmlower 3/2005.
 */
void resolve_inheritance(mangle_inherited_name_func *mfunc);


/* ----------------------------------------------------------------------- */
/* The transitive closure of the subclass/superclass and                   */
/* overwrites/overwrittenby relation.                                      */
/*                                                                         */
/* A walk over the ir (O(#types+#entities)) computes the transitive        */
/* closure.  Adding a new type/entity or changing the basic relations in   */
/* some other way invalidates the transitive closure, i.e., it is not      */
/* updated by the basic functions.                                         */
/*                                                                         */
/* The transitive edges are held in a set, not in an array as the          */
/* underlying relation.                                                    */
/*                                                                         */
/* Do the sets contain the node itself?  I assume NOT!                     */
/* ----------------------------------------------------------------------- */

/** The state of the transitive closure.
 *
 *  @todo: we could manage the state for each relation separately.  Invalidating
 *  the entity relations does not mean invalidating the class relation. */
typedef enum {
	inh_transitive_closure_none,       /**<  Closure is not computed, can not be accessed. */
	inh_transitive_closure_valid,      /**<  Closure computed and valid. */
	inh_transitive_closure_invalid,    /**<  Closure invalid, but can be accessed. */
	inh_transitive_closure_max         /**<  Invalid value. */
} inh_transitive_closure_state;

void                         set_irp_inh_transitive_closure_state(inh_transitive_closure_state s);
void                         invalidate_irp_inh_transitive_closure_state(void);
inh_transitive_closure_state get_irp_inh_transitive_closure_state(void);


/** Compute transitive closure of the subclass/superclass and
 * overwrites/overwrittenby relation.
 *
 * This function walks over the ir (O(\#types+\#entities)) to compute the
 * transitive closure.    */
void compute_inh_transitive_closure(void);

/** Free memory occupied by the transitive closure information. */
void free_inh_transitive_closure(void);


/* - subtype ------------------------------------------------------------- */

/** Iterate over all transitive subtypes. */
ir_type *get_class_trans_subtype_first(const ir_type *tp);
ir_type *get_class_trans_subtype_next(const ir_type *tp);
int is_class_trans_subtype(const ir_type *tp, const ir_type *subtp);

/* - supertype ----------------------------------------------------------- */

/** Iterate over all transitive supertypes. */
ir_type *get_class_trans_supertype_first(const ir_type *tp);
ir_type *get_class_trans_supertype_next(const ir_type *tp);

/* - overwrittenby ------------------------------------------------------- */

/** Iterate over all entities that transitive overwrite this entities. */
ir_entity *get_entity_trans_overwrittenby_first(const ir_entity *ent);
ir_entity *get_entity_trans_overwrittenby_next(const ir_entity *ent);

/* - overwrites ---------------------------------------------------------- */

/** Iterate over all transitive overwritten entities. */
ir_entity *get_entity_trans_overwrites_first(const ir_entity *ent);
ir_entity *get_entity_trans_overwrites_next(const ir_entity *ent);


/* ----------------------------------------------------------------------- */
/** The state of Cast operations that cast class types or pointers to class
 *  types.
 *
 * The state expresses, how far Cast operations conform with the class
 * hierarchy.
 *
 *   class A {}
 *   class B1 extends A {}
 *   class B2 extends A {}
 *   class C  extends B1 {}
 * normalized:  Cast operations conform with the inheritance relation.
 *   I.e., the type of the operand of a Cast is either a super= or a sub-
 *   type of the type casted to. Example: (A)((B2) (new C())).
 * transitive:  Cast operations conform with the transitive inheritance
 *   relation. Example: (A)(new C()).
 * any:  Cast operations do not conform with the transitive inheritance
 *   relation.  Example: (B2)(new B1())
 *
 *  @see: tropt.h
 */
/* ----------------------------------------------------------------------- */

/** Flags for class cast state.
 *
 * The state in irp is always smaller or equal to the state of any
 * irg.
 *
 * We rely on the ordering of the enum. */
typedef enum {
	ir_class_casts_any        = 0, /**< There are class casts that do not cast in conformance with
	                                    the class hierarchy.  @@@ So far this does not happen in Firm. */
	ir_class_casts_transitive = 1, /**< Class casts conform to transitive inheritance edges. Default. */
	ir_class_casts_normalized = 2, /**< Class casts conform to inheritance edges. */
	ir_class_casts_state_max
} ir_class_cast_state;
const char *get_class_cast_state_string(ir_class_cast_state s);

void                set_irg_class_cast_state(ir_graph *irg, ir_class_cast_state s);
ir_class_cast_state get_irg_class_cast_state(const ir_graph *irg);
void                set_irp_class_cast_state(ir_class_cast_state s);
ir_class_cast_state get_irp_class_cast_state(void);

/** Verify the class cast state of an irg.
 *
 *  Asserts if state is to high, outputs debug warning if state is to low
 *  and firm verbosity is set.
 */
void verify_irg_class_cast_state(ir_graph *irg);

/**
 * possible trvrfy() error codes
 */
enum trvrfy_error_codes {
	no_error = 0,                      /**< no error */
	error_ent_not_cont,                /**< overwritten entity not in superclass */
	error_null_mem,                    /**< compound contains NULL member */
	error_const_on_wrong_irg,          /**< constant placed on wrong IRG */
	error_existent_entity_without_irg, /**< Method entities with pecularity_exist must have an irg */
	error_wrong_ent_overwrites,        /**< number of entity overwrites exceeds number of class overwrites */
	error_inherited_ent_without_const, /**< inherited method entity not pointing to existent entity */
	error_glob_ent_allocation,         /**< wrong allocation of a global entity */
	error_ent_const_mode,              /**< Mode of constant in entity did not match entities type. */
	error_ent_wrong_owner              /**< Mode of constant in entity did not match entities type. */
};

/**
 * Checks a type.
 *
 * @return
 *  0   if no error encountered
 */
int check_type(ir_type *tp);

/**
 * Check an entity. Currently, we check only if initialized constants
 * are build on the const irg graph.
 *
 * @return
 *  0   if no error encountered
 *  != 0    a trvrfy_error_codes code
 */
int check_entity(ir_entity *ent);

/**
 * Walks the type information and performs a set of sanity checks.
 *
 * Currently, the following checks are executed:
 * - values of initialized entities must be allocated on the constant IRG
 * - class types: doesn't have NULL members
 * - class types: all overwrites are existent in the super type
 *
 * @return
 *    0 if graph is correct
 *    else error code.
 */
int tr_vrfy(void);

/**
 * If NDEBUG is defined performs nothing, else calls the tr_vrfy() function.
 */
#ifdef NDEBUG
#define TR_VRFY()	0
#else
#define TR_VRFY()	tr_vrfy()
#endif

/** Replaces one type by the other.
 *
 *  Old type is replaced by new_type.  All references to old_type
 *  now point to new_type.  The memory for the old type is destroyed,
 *  but still used.  Therefore it is not freed.
 *  All referenced to this memory will be lost after a certain while.
 *  An exception is the list of types in irp (irprog.h).
 *  In the future there might be a routine to recover the memory, but
 *  this will be at considerable runtime cost.
 *
 *  @param old_type  - The old type that shall be replaced by the new type.
 *  @param new_type  - The new type that will replace old_type.
 *
 */
void exchange_types(ir_type *old_type, ir_type *new_type);

/** Skip id types until a useful type is reached.
 *
 *  @param tp - A type of arbitrary kind.
 *
 *  @return
 *    tp if it is not an id type.
 *    If tp is an id type returns the real type it stands for.
 */
ir_type *skip_tid(ir_type *tp);

/**
 * @page type   representation of types
 *
 *  Datastructure to hold type information.
 *
 *  This module supplies a datastructure to represent all types
 *  known in the compiled program.  This includes types specified
 *  in the program as well as types defined by the language.  In the
 *  view of the intermediate representation there is no difference
 *  between these types.  Finally it specifies some auxiliary types.
 *
 *  There exist several kinds of types, arranged by the structure of
 *  the type.  A type is described by a set of attributes.  Some of
 *  these attributes are common to all types, others depend on the
 *  kind of the type.
 *
 *  Types are different from the modes defined in irmode:  Types are
 *  on the level of the programming language, modes at the level of
 *  the target processor.
 *
 *  @see  tpop.h
 */

#include "typerep.h"

/** Frees all entities associated with a type.
 *  Does not free the array entity.
 *  Warning: ensure these entities are not referenced anywhere else.
 */
void free_type_entities(ir_type *tp);

/** Frees the memory used by the type.
 *
 * Removes the type from the type list. Does not free the entities
 * belonging to the type, except for the array element entity.  Does
 * not free if tp is "none" or "unknown".  Frees entities in value
 * param subtypes of method types!!! Make sure these are not
 * referenced any more.  Further make sure there is no pointer type
 * that refers to this type.                           */
void free_type(ir_type *tp);

const tp_op *get_type_tpop(const ir_type *tp);
ident *get_type_tpop_nameid(const ir_type *tp);
const char *get_type_tpop_name(const ir_type *tp);
tp_opcode get_type_tpop_code(const ir_type *tp);

ident *get_type_ident(const ir_type *tp);
void set_type_ident(ir_type *tp, ident* id);
const char *get_type_name(const ir_type *tp);

/** The visibility of a type.
 *
 *  The visibility of a type indicates, whether entities of this type
 *  are accessed or allocated in external code.
 *
 *  An entity of a type is allocated in external code, if the external
 *  code declares a variable of this type, or dynamically allocates
 *  an entity of this type.  If the external code declares a (compound)
 *  type, that contains entities of this type, the visibility also
 *  must be external_allocated.
 *
 *  The visibility must be higher than that of all entities, if the
 *  type is a compound.  Here it is questionable, what happens with
 *  static entities.  If these are accessed external by direct reference,
 *  (a static call to a method, that is also in the dispatch table)
 *  it should not affect the visibility of the type.
 *
 *
 * @@@ Do we need a visibility for types?
 * I change the layout of types radically when doing type splitting.
 * I need to know, which fields of classes are accessed in the RTS,
 * e.g., [_length.  I may not move [_length to the split part.
 * The layout though, is a property of the type.
 *
 * One could also think of changing the mode of a type ...
 *
 * But, we could also output macros to access the fields, e.g.,
 *  ACCESS_[_length (X)   X->length              // conventional
 *  ACCESS_[_length (X)   X->_split_ref->length  // with type splitting
 *
 * For now I implement this function, that returns the visibility
 * based on the visibility of the entities of a compound ...
 *
 * This function returns visibility_external_visible if one or more
 * entities of a compound type have visibility_external_visible.
 * Entities of types are never visibility_external_allocated (right?).
 * Else returns visibility_local.
 */
ir_visibility get_type_visibility(const ir_type *tp);
void          set_type_visibility(ir_type *tp, ir_visibility v);



/** The state of the type layout. */
typedef enum {
	layout_undefined,    /**< The layout of this type is not defined.
	                          Address computation to access fields is not
	                          possible, fields must be accessed by Sel
	                          nodes.  Enumeration constants might be undefined.
	                          This is the default value except for
	                          pointer, primitive and method types. */
	layout_fixed         /**< The layout is fixed, all component/member entities
	                          have an offset assigned.  Size of the type is known.
	                          Arrays can be accessed by explicit address
	                          computation.  Enumeration constants must be defined.
	                          Default for pointer, primitive and method types. */
} ir_type_state;

/** Returns a human readable string for the enum entry. */
const char *get_type_state_name(ir_type_state s);

/** Returns the type layout state of a type. */
ir_type_state get_type_state(const ir_type *tp);

/** Sets the type layout state of a type.
 *
 * For primitives, pointer and method types the layout is always fixed.
 * This call is legal but has no effect.
 */
void set_type_state(ir_type *tp, ir_type_state state);

/** Returns the mode of a type.
 *
 * Returns NULL for all non atomic types.
 */
ir_mode *get_type_mode(const ir_type *tp);

/** Sets the mode of a type.
 *
 * Only has an effect on primitive, enumeration and pointer types.
 */
void set_type_mode(ir_type *tp, ir_mode* m);

/** Returns the size of a type in bytes. */
unsigned get_type_size_bytes(const ir_type *tp);

/** Sets the size of a type in bytes.
 *
 * For primitive, enumeration, pointer and method types the size
 * is always fixed. This call is legal but has no effect.
 */
void set_type_size_bytes(ir_type *tp, unsigned size);

/** Returns the alignment of a type in bytes. */
unsigned get_type_alignment_bytes(ir_type *tp);

/** Returns the alignment of a type in bits.
 *
 *  If the alignment of a type is
 *  not set, it is calculated here according to the following rules:
 *  -#.) if a type has a mode, the alignment is the mode size.
 *  -#.) compound types have the alignment of there biggest member.
 *  -#.) array types have the alignment of there element type.
 *  -#.) method types return 0 here.
 *  -#.) all other types return 1 here (i.e. aligned at byte).
 */
void set_type_alignment_bytes(ir_type *tp, unsigned align);

/** Returns the visited count of a type. */
ir_visited_t get_type_visited(const ir_type *tp);
/** Sets the visited count of a type to num. */
void set_type_visited(ir_type *tp, ir_visited_t num);
/** Sets visited field in type to type_visited. */
void mark_type_visited(ir_type *tp);
/** Returns non-zero if the type is already visited */
int type_visited(const ir_type *tp);
/** Returns non-zero if the type is not yet visited */
int type_not_visited(const ir_type *tp);

/** Returns the associated link field of a type. */
void *get_type_link(const ir_type *tp);
/** Sets the associated link field of a type. */
void set_type_link(ir_type *tp, void *l);

/**
 * Visited flag to traverse the type information.
 *
 * Increase this flag by one before traversing the type information
 * using inc_master_type_visited().
 * Mark type nodes as visited by mark_type_visited(ir_type).
 * Check whether node was already visited by type_visited(ir_type)
 * and type_not_visited(ir_type).
 * Or use the function to walk all types.
 *
 * @see  typewalk
 */
void         set_master_type_visited(ir_visited_t val);
ir_visited_t get_master_type_visited(void);
void         inc_master_type_visited(void);

/**
 * Sets the debug information of a type.
 *
 * @param tp  The type.
 * @param db  The debug info.
 */
void set_type_dbg_info(ir_type *tp, dbg_info *db);

/**
 * Returns the debug information of a type.
 *
 * @param tp  The type.
 */
dbg_info *get_type_dbg_info(const ir_type *tp);

/**
 * Checks whether a pointer points to a type.
 *
 * @param thing     an arbitrary pointer
 *
 * @return
 *     true if the thing is a type, else false
 */
int is_type(const void *thing);

/**
 *   Checks whether two types are structurally equal.
 *
 *   @param typ1  the first type
 *   @param typ2  the second type
 *
 *   @return
 *    true if the types are equal, else false.
 *
 *   Types are equal if :
 *    - they are the same type kind
 *    - they have the same name
 *    - they have the same mode (if applicable)
 *    - they have the same type_state and, ev., the same size
 *    - they are class types and have:
 *      - the same members (see same_entity in entity.h)
 *      - the same supertypes -- the C-pointers are compared --> no recursive call.
 *      - the same number of subtypes.  Subtypes are not compared,
 *        as this could cause a cyclic test.
 *      - the same peculiarity
 *    - they are structure types and have the same members
 *    - they are method types and have
 *      - the same parameter types
 *      - the same result types
 *    - they are union types and have the same members
 *    - they are array types and have
 *      - the same number of dimensions
 *      - the same dimension bounds
 *      - the same dimension order
 *      - the same element type
 *    - they are enumeration types and have the same enumerator names
 *    - they are pointer types and have the identical points_to type
 *      (i.e., the same C-struct to represent the type, type_id is skipped.
 *       This is to avoid endless recursions; with pointer types cyclic
 *       type graphs are possible.)
 */
int equal_type(ir_type *typ1, ir_type *typ2);

/**
 *   Checks whether two types are structural comparable.
 *
 *   @param st pointer type
 *   @param lt pointer type
 *
 *   @return
 *    true if type st is smaller than type lt, i.e. whenever
 *    lt is expected a st can be used.
 *    This is true if
 *    - they are the same type kind
 *    - mode(st) < mode (lt)  (if applicable)
 *    - they are class types and st is (transitive) subtype of lt,
 *    - they are structure types and
 *       - the members of st have exactly one counterpart in lt with the same name,
 *       - the counterpart has a bigger type.
 *    - they are method types and have
 *      - the same number of parameter and result types,
 *      - the parameter types of st are smaller than those of lt,
 *      - the result types of st are smaller than those of lt
 *    - they are union types and have the members of st have exactly one
 *      @return counterpart in lt and the type is smaller
 *    - they are array types and have
 *      - the same number of dimensions
 *      - all bounds of lt are bound of st
 *      - the same dimension order
 *      - the same element type
 *      @return or
 *      - the element type of st is smaller than that of lt
 *      - the element types have the same size and fixed layout.
 *    - they are enumeration types and have the same enumerator names
 *    - they are pointer types and have the points_to type of st is
 *      @return smaller than the points_to type of lt.
 *
 */
int smaller_type(ir_type *st, ir_type *lt);

/**
 *  @page class_type    Representation of a class type
 *
 *  If the type opcode is set to type_class the type represents class
 *  types.  A list of fields and methods is associated with a class.
 *  Further a class can inherit from and bequest to other classes.
 *
 *  The following attributes are private to this type kind:
 *  - member:     All entities belonging to this class.  This are method entities
 *                which have type_method or fields that can have any of the
 *                following type kinds: type_class, type_struct, type_union,
 *                type_array, type_enumeration, type_pointer, type_primitive.
 *
 *  The following two are dynamic lists that can be grown with an "add_" function,<