(root)/
gcc-13.2.0/
gcc/
ada/
gcc-interface/
gigi.h
       1  /****************************************************************************
       2   *                                                                          *
       3   *                         GNAT COMPILER COMPONENTS                         *
       4   *                                                                          *
       5   *                                 G I G I                                  *
       6   *                                                                          *
       7   *                              C Header File                               *
       8   *                                                                          *
       9   *          Copyright (C) 1992-2023, Free Software Foundation, Inc.         *
      10   *                                                                          *
      11   * GNAT is free software;  you can  redistribute it  and/or modify it under *
      12   * terms of the  GNU General Public License as published  by the Free Soft- *
      13   * ware  Foundation;  either version 3,  or (at your option) any later ver- *
      14   * sion.  GNAT is distributed in the hope that it will be useful, but WITH- *
      15   * OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY *
      16   * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License *
      17   * for  more details.  You should have  received  a copy of the GNU General *
      18   * Public License  distributed  with GNAT;  see file  COPYING3.  If not see *
      19   * <http://www.gnu.org/licenses/>.                                          *
      20   *                                                                          *
      21   * GNAT was originally developed  by the GNAT team at  New York University. *
      22   * Extensive contributions were provided by Ada Core Technologies Inc.      *
      23   *                                                                          *
      24   ****************************************************************************/
      25  
      26  /* Declare all functions and types used by gigi.  */
      27  
      28  /* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
      29     entity, this routine returns the equivalent GCC tree for that entity
      30     (an ..._DECL node) and associates the ..._DECL node with the input GNAT
      31     defining identifier.
      32  
      33     If GNAT_ENTITY is a variable or a constant declaration, GNU_EXPR gives its
      34     initial value (in GCC tree form). This is optional for variables.
      35     For renamed entities, GNU_EXPR gives the object being renamed.
      36  
      37     DEFINITION is true if this call is intended for a definition.  This is used
      38     for separate compilation where it is necessary to know whether an external
      39     declaration or a definition must be created if the GCC equivalent was not
      40     created previously.  */
      41  extern tree gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr,
      42                                  bool definition);
      43  
      44  /* Similar, but if the returned value is a COMPONENT_REF, return the
      45     FIELD_DECL.  */
      46  extern tree gnat_to_gnu_field_decl (Entity_Id gnat_entity);
      47  
      48  /* Similar, but GNAT_ENTITY is assumed to refer to a GNAT type.  Return
      49     the GCC type corresponding to that entity.  */
      50  extern tree gnat_to_gnu_type (Entity_Id gnat_entity);
      51  
      52  /* Update the GCC tree previously built for the profiles involving GNU_TYPE,
      53     a dummy type which appears in profiles.  */
      54  extern void update_profiles_with (tree gnu_type);
      55  
      56  /* Start a new statement group chained to the previous group.  */
      57  extern void start_stmt_group (void);
      58  
      59  /* Add GNU_STMT to the current statement group.  If it is an expression with
      60     no effects, it is ignored.  */
      61  extern void add_stmt (tree gnu_stmt);
      62  
      63  /* Similar, but the statement is always added, regardless of side-effects.  */
      64  extern void add_stmt_force (tree gnu_stmt);
      65  
      66  /* Like add_stmt, but set the location of GNU_STMT to that of GNAT_NODE.  */
      67  extern void add_stmt_with_node (tree gnu_stmt, Node_Id gnat_node);
      68  
      69  /* Similar, but the statement is always added, regardless of side-effects.  */
      70  extern void add_stmt_with_node_force (tree gnu_stmt, Node_Id gnat_node);
      71  
      72  /* Return code corresponding to the current code group.  It is normally
      73     a STATEMENT_LIST, but may also be a BIND_EXPR or TRY_FINALLY_EXPR if
      74     BLOCK or cleanups were set.  */
      75  extern tree end_stmt_group (void);
      76  
      77  /* Set the BLOCK node corresponding to the current code group to GNU_BLOCK.  */
      78  extern void set_block_for_group (tree);
      79  
      80  /* Add a declaration statement for GNU_DECL to the current statement group.
      81     Get the SLOC to be put onto the statement from GNAT_NODE.  */
      82  extern void add_decl_expr (tree gnu_decl, Node_Id gnat_node);
      83  
      84  /* Mark nodes rooted at T with TREE_VISITED and types as having their
      85     sized gimplified.  We use this to indicate all variable sizes and
      86     positions in global types may not be shared by any subprogram.  */
      87  extern void mark_visited (tree t);
      88  
      89  /* This macro calls the above function but short-circuits the common
      90     case of a constant to save time and also checks for NULL.  */
      91  #define MARK_VISITED(EXP)		\
      92  do {					\
      93    if((EXP) && !CONSTANT_CLASS_P (EXP))	\
      94      mark_visited (EXP);			\
      95  } while (0)
      96  
      97  /* Finalize the processing of From_Limited_With incomplete types.  */
      98  extern void finalize_from_limited_with (void);
      99  
     100  /* Return the equivalent type to be used for GNAT_ENTITY, if it's a kind
     101     of type (such E_Task_Type) that has a different type which Gigi uses
     102     for its representation.  If the type does not have a special type for
     103     its representation, return GNAT_ENTITY.  */
     104  extern Entity_Id Gigi_Equivalent_Type (Entity_Id gnat_entity);
     105  
     106  /* Given GNAT_ENTITY, elaborate all expressions that are required to
     107     be elaborated at the point of its definition, but do nothing else.  */
     108  extern void elaborate_entity (Entity_Id gnat_entity);
     109  
     110  /* Get the unpadded version of a GNAT type.  */
     111  extern tree get_unpadded_type (Entity_Id gnat_entity);
     112  
     113  /* Create a record type that contains a SIZE bytes long field of TYPE with a
     114      starting bit position so that it is aligned to ALIGN bits, and leaving at
     115      least ROOM bytes free before the field.  BASE_ALIGN is the alignment the
     116      record is guaranteed to get.  GNAT_NODE is used for the position of the
     117      associated TYPE_DECL.  */
     118  extern tree make_aligning_type (tree type, unsigned int align, tree size,
     119  				unsigned int base_align, int room, Node_Id);
     120  
     121  /* TYPE is a RECORD_TYPE, UNION_TYPE or QUAL_UNION_TYPE that is being used
     122     as the field type of a packed record if IN_RECORD is true, or as the
     123     component type of a packed array if IN_RECORD is false.  See if we can
     124     rewrite it either as a type that has a non-BLKmode, which we can pack
     125     tighter in the packed record case, or as a smaller type with at most
     126     MAX_ALIGN alignment if the value is non-zero.  If so, return the new
     127     type; if not, return the original type.  */
     128  extern tree make_packable_type (tree type, bool in_record,
     129  				unsigned int max_align);
     130  
     131  /* Given a type TYPE, return a new type whose size is appropriate for SIZE.
     132     If TYPE is the best type, return it.  Otherwise, make a new type.  We
     133     only support new integral and pointer types.  FOR_BIASED is true if
     134     we are making a biased type.  */
     135  extern tree make_type_from_size (tree type, tree size_tree, bool for_biased);
     136  
     137  /* Ensure that TYPE has SIZE and ALIGN.  Make and return a new padded type
     138     if needed.  We have already verified that SIZE and ALIGN are large enough.
     139     GNAT_ENTITY is used to name the resulting record and to issue a warning.
     140     IS_COMPONENT_TYPE is true if this is being done for the component type of
     141     an array.  DEFINITION is true if this type is being defined.  SET_RM_SIZE
     142     is true if the RM size of the resulting type is to be set to SIZE too; in
     143     this case, the padded type is canonicalized before being returned.  */
     144  extern tree maybe_pad_type (tree type, tree size, unsigned int align,
     145  			    Entity_Id gnat_entity, bool is_component_type,
     146  			    bool definition, bool set_rm_size);
     147  
     148  /* Return true if padded TYPE was built with an RM size.  */
     149  extern bool pad_type_has_rm_size (tree type);
     150  
     151  /* Return a copy of the padded TYPE but with reverse storage order.  */
     152  extern tree set_reverse_storage_order_on_pad_type (tree type);
     153  
     154  enum alias_set_op
     155  {
     156    ALIAS_SET_COPY,
     157    ALIAS_SET_SUBSET,
     158    ALIAS_SET_SUPERSET
     159  };
     160  
     161  /* Relate the alias sets of GNU_NEW_TYPE and GNU_OLD_TYPE according to OP.
     162     If this is a multi-dimensional array type, do this recursively.
     163  
     164     OP may be
     165     - ALIAS_SET_COPY:     the new set is made a copy of the old one.
     166     - ALIAS_SET_SUPERSET: the new set is made a superset of the old one.
     167     - ALIAS_SET_SUBSET:   the new set is made a subset of the old one.  */
     168  extern void relate_alias_sets (tree gnu_new_type, tree gnu_old_type,
     169  			       enum alias_set_op op);
     170  
     171  /* Given GNAT_ENTITY, an object (constant, variable, parameter, exception)
     172     and GNU_TYPE, its corresponding GCC type, set Esize and Alignment to the
     173     size and alignment used by Gigi.  Prefer SIZE over TYPE_SIZE if non-null.
     174     BY_REF is true if the object is used by reference.  */
     175  extern void annotate_object (Entity_Id gnat_entity, tree gnu_type, tree size,
     176  			     bool by_ref);
     177  
     178  /* Return the variant part of RECORD_TYPE, if any.  Otherwise return NULL.  */
     179  extern tree get_variant_part (tree record_type);
     180  
     181  /* Given a type T, a FIELD_DECL F, and a replacement value R, return a new
     182     type with all size expressions that contain F updated by replacing F
     183     with R.  If F is NULL_TREE, always make a new RECORD_TYPE, even if
     184     nothing has changed.  */
     185  extern tree substitute_in_type (tree t, tree f, tree r);
     186  
     187  /* Return the RM size of GNU_TYPE.  This is the actual number of bits
     188     needed to represent the object.  */
     189  extern tree rm_size (tree gnu_type);
     190  
     191  /* Return the name to be used for GNAT_ENTITY.  If a type, create a
     192     fully-qualified name, possibly with type information encoding.
     193     Otherwise, return the name.  */
     194  extern tree get_entity_name (Entity_Id gnat_entity);
     195  
     196  /* Return an identifier representing the external name to be used for
     197     GNAT_ENTITY.  If SUFFIX is specified, the name is followed by "___"
     198     and the specified suffix.  */
     199  extern tree create_concat_name (Entity_Id gnat_entity, const char *suffix);
     200  
     201  /* Given GNU_NAME, an IDENTIFIER_NODE containing a name and SUFFIX, a
     202     string, return a new IDENTIFIER_NODE that is the concatenation of
     203     the name followed by "___" and the specified suffix.  */
     204  extern tree concat_name (tree gnu_name, const char *suffix);
     205  
     206  /* Initialize data structures of the decl.cc module.  */
     207  extern void init_gnat_decl (void);
     208  
     209  /* Destroy data structures of the decl.cc module.  */
     210  extern void destroy_gnat_decl (void);
     211  
     212  /* Highest number in the front-end node table.  */
     213  extern int max_gnat_nodes;
     214  
     215  /* True when gigi is being called on an analyzed but unexpanded
     216     tree, and the only purpose of the call is to properly annotate
     217     types with representation information.  */
     218  extern bool type_annotate_only;
     219  
     220  /* This structure must be kept synchronized with Call_Back_End.  */
     221  struct File_Info_Type
     222  {
     223    File_Name_Type File_Name;
     224    Instance_Id    Instance;
     225    Nat            Num_Source_Lines;
     226  };
     227  
     228  #ifdef __cplusplus
     229  extern "C" {
     230  #endif
     231  
     232  /* This is the main program of the back-end.  It sets up all the table
     233     structures and then generates code.  */
     234  extern void gigi (Node_Id gnat_root,
     235  	          int max_gnat_node,
     236  		  int number_name,
     237  		  Node_Header *node_offsets_ptr,
     238  		  any_slot *slots_ptr,
     239  		  Node_Id *next_node_ptr,
     240  		  Node_Id *prev_node_ptr,
     241  		  struct Elist_Header *elists_ptr,
     242  		  struct Elmt_Item *elmts_ptr,
     243  		  struct String_Entry *strings_ptr,
     244  		  Char_Code *strings_chars_ptr,
     245  		  struct List_Header *list_headers_ptr,
     246  		  Nat number_file,
     247  		  struct File_Info_Type *file_info_ptr,
     248  		  Entity_Id standard_boolean,
     249  		  Entity_Id standard_integer,
     250  		  Entity_Id standard_character,
     251  		  Entity_Id standard_long_long_float,
     252  		  Entity_Id standard_exception_type,
     253  		  Int gigi_operating_mode);
     254  
     255  #ifdef __cplusplus
     256  }
     257  #endif
     258  
     259  /* GNAT_NODE is the root of some GNAT tree.  Return the root of the
     260     GCC tree corresponding to that GNAT tree.  */
     261  extern tree gnat_to_gnu (Node_Id gnat_node);
     262  
     263  /* Similar to gnat_to_gnu, but discard any object that might be created in
     264     the course of the translation of GNAT_NODE, which must be an "external"
     265     expression in the sense that it will be elaborated elsewhere.  */
     266  extern tree gnat_to_gnu_external (Node_Id gnat_node);
     267  
     268  /* GNU_STMT is a statement.  We generate code for that statement.  */
     269  extern void gnat_expand_stmt (tree gnu_stmt);
     270  
     271  /* Generate GIMPLE in place for the expression at *EXPR_P.  */
     272  extern int gnat_gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *);
     273  
     274  /* Do the processing for the declaration of a GNAT_ENTITY, a type.  If
     275     a separate Freeze node exists, delay the bulk of the processing.  Otherwise
     276     make a GCC type for GNAT_ENTITY and set up the correspondence.  */
     277  extern void process_type (Entity_Id gnat_entity);
     278  
     279  /* Convert SLOC into LOCUS.  Return true if SLOC corresponds to a source code
     280     location and false if it doesn't.  If CLEAR_COLUMN is true, set the column
     281     information to 0.  */
     282  extern bool Sloc_to_locus (Source_Ptr Sloc, location_t *locus,
     283  			   bool clear_column = false, const_tree decl = 0);
     284  
     285  /* Post an error message.  MSG is the error message, properly annotated.
     286     NODE is the node at which to post the error and the node to use for the
     287     '&' substitution.  */
     288  extern void post_error (const char *msg, Node_Id node);
     289  
     290  /* Similar to post_error, but NODE is the node at which to post the error and
     291     ENT is the node to use for the '&' substitution.  */
     292  extern void post_error_ne (const char *msg, Node_Id node, Entity_Id ent);
     293  
     294  /* Similar to post_error_ne, but NUM is the number to use for the '^'.  */
     295  extern void post_error_ne_num (const char *msg, Node_Id node, Entity_Id ent,
     296                                 int num);
     297  
     298  /* Similar to post_error_ne, but T is a GCC tree representing the number to
     299     write.  If T represents a constant, the text inside curly brackets in
     300     MSG will be output (presumably including a '^').  Otherwise it will not
     301     be output and the text inside square brackets will be output instead.  */
     302  extern void post_error_ne_tree (const char *msg, Node_Id node, Entity_Id ent,
     303                                  tree t);
     304  
     305  /* Similar to post_error_ne_tree, but NUM is a second integer to write.  */
     306  extern void post_error_ne_tree_2 (const char *msg, Node_Id node, Entity_Id ent,
     307                                    tree t, int num);
     308  
     309  /* Return a label to branch to for the exception type in KIND or Empty
     310     if none.  */
     311  extern Entity_Id get_exception_label (char kind);
     312  
     313  /* If nonzero, pretend we are allocating at global level.  */
     314  extern int force_global;
     315  
     316  /* The default alignment of "double" floating-point types, i.e. floating
     317     point types whose size is equal to 64 bits, or 0 if this alignment is
     318     not specifically capped.  */
     319  extern int double_float_alignment;
     320  
     321  /* The default alignment of "double" or larger scalar types, i.e. scalar
     322     types whose size is greater or equal to 64 bits, or 0 if this alignment
     323     is not specifically capped.  */
     324  extern int double_scalar_alignment;
     325  
     326  /* True if floating-point arithmetics may use wider intermediate results.  */
     327  extern bool fp_arith_may_widen;
     328  
     329  /* Data structures used to represent attributes.  */
     330  
     331  enum attrib_type
     332  {
     333    ATTR_MACHINE_ATTRIBUTE,
     334    ATTR_LINK_ALIAS,
     335    ATTR_LINK_SECTION,
     336    ATTR_LINK_CONSTRUCTOR,
     337    ATTR_LINK_DESTRUCTOR,
     338    ATTR_THREAD_LOCAL_STORAGE,
     339    ATTR_WEAK_EXTERNAL
     340  };
     341  
     342  struct attrib
     343  {
     344    struct attrib *next;
     345    enum attrib_type type;
     346    tree name;
     347    tree args;
     348    Node_Id error_point;
     349  };
     350  
     351  /* Table of machine-independent internal attributes.  */
     352  extern const struct attribute_spec gnat_internal_attribute_table[];
     353  
     354  /* Define the entries in the standard data array.  */
     355  enum standard_datatypes
     356  {
     357    /* The longest floating-point type.  */
     358    ADT_longest_float_type,
     359  
     360    /* The type of an exception.  */
     361    ADT_except_type,
     362  
     363    /* Function type declaration -- void T() */
     364    ADT_void_ftype,
     365  
     366    /* Type declaration node  <==> typedef void *T() */
     367    ADT_ptr_void_ftype,
     368  
     369    /* Type declaration node  <==> typedef virtual void *T() */
     370    ADT_fdesc_type,
     371  
     372    /* Null pointer for above type.  */
     373    ADT_null_fdesc,
     374  
     375    /* Value 1 in signed bitsizetype.  */
     376    ADT_sbitsize_one_node,
     377  
     378    /* Value BITS_PER_UNIT in signed bitsizetype.  */
     379    ADT_sbitsize_unit_node,
     380  
     381    /* Function declaration node for run-time allocation function.  */
     382    ADT_malloc_decl,
     383  
     384    /* Function declaration node for run-time freeing function.  */
     385    ADT_free_decl,
     386  
     387    /* Function declaration node for run-time reallocation function.  */
     388    ADT_realloc_decl,
     389  
     390    /* Function decl node for 64-bit multiplication with overflow checking.  */
     391    ADT_mulv64_decl,
     392  
     393    /* Function decl node for 128-bit multiplication with overflow checking.  */
     394    ADT_mulv128_decl,
     395  
     396    /* Identifier for the name of the _Parent field in tagged record types.  */
     397    ADT_parent_name_id,
     398  
     399    /* Identifier for the name of the Not_Handled_By_Others field.  */
     400    ADT_not_handled_by_others_name_id,
     401  
     402    /* Types and decls used by the exception mechanism.  */
     403    ADT_reraise_zcx_decl,
     404    ADT_set_exception_parameter_decl,
     405    ADT_begin_handler_decl,
     406    ADT_end_handler_decl,
     407    ADT_unhandled_except_decl,
     408    ADT_others_decl,
     409    ADT_all_others_decl,
     410    ADT_unhandled_others_decl,
     411  
     412    ADT_LAST
     413  };
     414  
     415  /* Define kind of exception information associated with raise statements.  */
     416  enum exception_info_kind
     417  {
     418    /* Simple exception information: file:line.  */
     419    exception_simple,
     420    /* Range exception information: file:line + index, first, last.  */
     421    exception_range,
     422    /* Column exception information: file:line:column.  */
     423    exception_column
     424  };
     425  
     426  /* Define the inline status of a subprogram.  */
     427  enum inline_status_t
     428  {
     429    /* Inlining is suppressed for the subprogram.  */
     430    is_suppressed,
     431    /* No inlining is requested for the subprogram.  */
     432    is_default,
     433    /* Inlining is requested for the subprogram.  */
     434    is_requested,
     435    /* Inlining is strongly requested for the subprogram.  */
     436    is_prescribed,
     437    /* Inlining is required for the subprogram.  */
     438    is_required
     439  };
     440  
     441  extern GTY(()) tree gnat_std_decls[(int) ADT_LAST];
     442  extern GTY(()) tree gnat_raise_decls[(int) LAST_REASON_CODE + 1];
     443  extern GTY(()) tree gnat_raise_decls_ext[(int) LAST_REASON_CODE + 1];
     444  
     445  #define longest_float_type_node gnat_std_decls[(int) ADT_longest_float_type]
     446  #define except_type_node gnat_std_decls[(int) ADT_except_type]
     447  #define void_ftype gnat_std_decls[(int) ADT_void_ftype]
     448  #define ptr_void_ftype gnat_std_decls[(int) ADT_ptr_void_ftype]
     449  #define fdesc_type_node gnat_std_decls[(int) ADT_fdesc_type]
     450  #define null_fdesc_node gnat_std_decls[(int) ADT_null_fdesc]
     451  #define sbitsize_one_node gnat_std_decls[(int) ADT_sbitsize_one_node]
     452  #define sbitsize_unit_node gnat_std_decls[(int) ADT_sbitsize_unit_node]
     453  #define malloc_decl gnat_std_decls[(int) ADT_malloc_decl]
     454  #define free_decl gnat_std_decls[(int) ADT_free_decl]
     455  #define realloc_decl gnat_std_decls[(int) ADT_realloc_decl]
     456  #define mulv64_decl gnat_std_decls[(int) ADT_mulv64_decl]
     457  #define mulv128_decl gnat_std_decls[(int) ADT_mulv128_decl]
     458  #define parent_name_id gnat_std_decls[(int) ADT_parent_name_id]
     459  #define not_handled_by_others_name_id \
     460  	  gnat_std_decls[(int) ADT_not_handled_by_others_name_id]
     461  #define reraise_zcx_decl gnat_std_decls[(int) ADT_reraise_zcx_decl]
     462  #define set_exception_parameter_decl \
     463  	  gnat_std_decls[(int) ADT_set_exception_parameter_decl]
     464  #define begin_handler_decl gnat_std_decls[(int) ADT_begin_handler_decl]
     465  #define end_handler_decl gnat_std_decls[(int) ADT_end_handler_decl]
     466  #define unhandled_except_decl gnat_std_decls[(int) ADT_unhandled_except_decl]
     467  #define others_decl gnat_std_decls[(int) ADT_others_decl]
     468  #define all_others_decl gnat_std_decls[(int) ADT_all_others_decl]
     469  #define unhandled_others_decl gnat_std_decls[(int) ADT_unhandled_others_decl]
     470  
     471  /* Routines expected by the gcc back-end. They must have exactly the same
     472     prototype and names as below.  */
     473  
     474  /* Return true if we are in the global binding level.  */
     475  extern bool global_bindings_p (void);
     476  
     477  /* Enter and exit a new binding level.  */
     478  extern void gnat_pushlevel (void);
     479  extern void gnat_poplevel (void);
     480  extern void gnat_zaplevel (void);
     481  
     482  /* Set SUPERCONTEXT of the BLOCK for the current binding level to FNDECL
     483     and point FNDECL to this BLOCK.  */
     484  extern void set_current_block_context (tree fndecl);
     485  
     486  /* Record DECL as belonging to the current lexical scope and use GNAT_NODE
     487     for location information and flag propagation.  */
     488  extern void gnat_pushdecl (tree decl, Node_Id gnat_node);
     489  
     490  /* Initialize the GCC support for exception handling.  */
     491  extern void gnat_init_gcc_eh (void);
     492  
     493  /* Initialize the GCC support for floating-point operations.  */
     494  extern void gnat_init_gcc_fp (void);
     495  
     496  /* Install the builtin functions we might need.  */
     497  extern void gnat_install_builtins (void);
     498  
     499  /* Return an integer type with the number of bits of precision given by
     500     PRECISION.  UNSIGNEDP is nonzero if the type is unsigned; otherwise
     501     it is a signed type.  */
     502  extern tree gnat_type_for_size (unsigned precision, int unsignedp);
     503  
     504  /* Return a data type that has machine mode MODE.  UNSIGNEDP selects
     505     an unsigned type; otherwise a signed type is returned.  */
     506  extern tree gnat_type_for_mode (machine_mode mode, int unsignedp);
     507  
     508  /* Perform final processing on global declarations.  */
     509  extern void gnat_write_global_declarations (void);
     510  
     511  /* Return the signed or unsigned version of TYPE_NODE, a scalar type, the
     512     signedness being specified by UNSIGNEDP.  */
     513  extern tree gnat_signed_or_unsigned_type_for (int unsignedp, tree type_node);
     514  
     515  /* Return 1 if the types T1 and T2 are compatible, i.e. if they can be
     516     transparently converted to each other.  */
     517  extern int gnat_types_compatible_p (tree t1, tree t2);
     518  
     519  /* Return true if EXPR is a useless type conversion.  */
     520  extern bool gnat_useless_type_conversion (tree expr);
     521  
     522  /* Return true if T, a {FUNCTION,METHOD}_TYPE, has the specified flags.  */
     523  extern bool fntype_same_flags_p (const_tree, tree, bool, bool);
     524  
     525  /* Create an expression whose value is that of EXPR,
     526     converted to type TYPE.  The TREE_TYPE of the value
     527     is always TYPE.  This function implements all reasonable
     528     conversions; callers should filter out those that are
     529     not permitted by the language being compiled.  */
     530  extern tree convert (tree type, tree expr);
     531  
     532  /* Create an expression whose value is that of EXPR converted to the common
     533     index type, which is sizetype.  */
     534  extern tree convert_to_index_type (tree expr);
     535  
     536  /* Routines created solely for the tree translator's sake. Their prototypes
     537     can be changed as desired.  */
     538  
     539  /* Initialize data structures of the utils.cc module.  */
     540  extern void init_gnat_utils (void);
     541  
     542  /* Destroy data structures of the utils.cc module.  */
     543  extern void destroy_gnat_utils (void);
     544  
     545  /* GNAT_ENTITY is a GNAT tree node for a defining identifier.
     546     GNU_DECL is the GCC tree which is to be associated with
     547     GNAT_ENTITY. Such gnu tree node is always an ..._DECL node.
     548     If NO_CHECK is nonzero, the latter check is suppressed.
     549     If GNU_DECL is zero, a previous association is to be reset.  */
     550  extern void save_gnu_tree (Entity_Id gnat_entity, tree gnu_decl,
     551                             bool no_check);
     552  
     553  /* GNAT_ENTITY is a GNAT tree node for a defining identifier.
     554     Return the ..._DECL node that was associated with it.  If there is no tree
     555     node associated with GNAT_ENTITY, abort.  */
     556  extern tree get_gnu_tree (Entity_Id gnat_entity);
     557  
     558  /* Return nonzero if a GCC tree has been associated with GNAT_ENTITY.  */
     559  extern bool present_gnu_tree (Entity_Id gnat_entity);
     560  
     561  /* Make a dummy type corresponding to GNAT_TYPE.  */
     562  extern tree make_dummy_type (Entity_Id gnat_type);
     563  
     564  /* Return the dummy type that was made for GNAT_TYPE, if any.  */
     565  extern tree get_dummy_type (Entity_Id gnat_type);
     566  
     567  /* Build dummy fat and thin pointer types whose designated type is specified
     568     by GNAT_DESIG_TYPE/GNU_DESIG_TYPE and attach them to the latter.  */
     569  extern void build_dummy_unc_pointer_types (Entity_Id gnat_desig_type,
     570  					   tree gnu_desig_type);
     571  
     572  /* Record TYPE as a builtin type for Ada.  NAME is the name of the type.
     573     ARTIFICIAL_P is true if the type was generated by the compiler.  */
     574  extern void record_builtin_type (const char *name, tree type,
     575  				 bool artificial_p);
     576  
     577  /* Finish constructing the character type CHAR_TYPE.  */
     578  extern void finish_character_type (tree char_type);
     579  
     580  /* Given a record type RECORD_TYPE and a list of FIELD_DECL nodes FIELD_LIST,
     581     finish constructing the record type as a fat pointer type.  */
     582  extern void finish_fat_pointer_type (tree record_type, tree field_list);
     583  
     584  /* Given a record type RECORD_TYPE and a list of FIELD_DECL nodes FIELD_LIST,
     585     finish constructing the record or union type.  If REP_LEVEL is zero, this
     586     record has no representation clause and so will be entirely laid out here.
     587     If REP_LEVEL is one, this record has a representation clause and has been
     588     laid out already; only set the sizes and alignment.  If REP_LEVEL is two,
     589     this record is derived from a parent record and thus inherits its layout;
     590     only make a pass on the fields to finalize them.  DEBUG_INFO_P is true if
     591     additional debug info needs to be output for this type.  */
     592  extern void finish_record_type (tree record_type, tree field_list,
     593  				int rep_level, bool debug_info_p);
     594  
     595  /* Wrap up compilation of RECORD_TYPE, i.e. output additional debug info
     596     associated with it.  It need not be invoked directly in most cases as
     597     finish_record_type takes care of doing so.  */
     598  extern void rest_of_record_type_compilation (tree record_type);
     599  
     600  /* Append PARALLEL_TYPE on the chain of parallel types for TYPE.  */
     601  extern void add_parallel_type (tree type, tree parallel_type);
     602  
     603  /* Return a copy of TYPE, but safe to modify in any way.  */
     604  extern tree copy_type (tree type);
     605  
     606  /* Return a subtype of sizetype with range MIN to MAX and whose
     607     TYPE_INDEX_TYPE is INDEX.  GNAT_NODE is used for the position
     608     of the associated TYPE_DECL.  */
     609  extern tree create_index_type (tree min, tree max, tree index,
     610  			       Node_Id gnat_node);
     611  
     612  /* Return a subtype of TYPE with range MIN to MAX.  If TYPE is NULL,
     613     sizetype is used.  */
     614  extern tree create_range_type (tree type, tree min, tree max);
     615  
     616  /* Return an extra subtype of TYPE with range MIN to MAX.  */
     617  extern tree create_extra_subtype (tree type, tree min, tree max);
     618  
     619  /* Return a TYPE_DECL node suitable for the TYPE_STUB_DECL field of TYPE.
     620     NAME gives the name of the type to be used in the declaration.  */
     621  extern tree create_type_stub_decl (tree name, tree type);
     622  
     623  /* Return a TYPE_DECL node for TYPE.  NAME gives the name of the type to be
     624     used in the declaration.  ARTIFICIAL_P is true if the declaration was
     625     generated by the compiler.  DEBUG_INFO_P is true if we need to write
     626     debug information about this type.  GNAT_NODE is used for the position
     627     of the decl.  */
     628  extern tree create_type_decl (tree name, tree type, bool artificial_p,
     629  			      bool debug_info_p, Node_Id gnat_node);
     630  
     631  /* Return a VAR_DECL or CONST_DECL node.
     632  
     633     NAME gives the name of the variable.  ASM_NAME is its assembler name
     634     (if provided).  TYPE is its data type (a GCC ..._TYPE node).  INIT is
     635     the GCC tree for an optional initial expression; NULL_TREE if none.
     636  
     637     CONST_FLAG is true if this variable is constant, in which case we might
     638     return a CONST_DECL node unless CONST_DECL_ALLOWED_P is false.
     639  
     640     PUBLIC_FLAG is true if this is for a reference to a public entity or for a
     641     definition to be made visible outside of the current compilation unit, for
     642     instance variable definitions in a package specification.
     643  
     644     EXTERN_FLAG is true when processing an external variable declaration (as
     645     opposed to a definition: no storage is to be allocated for the variable).
     646  
     647     STATIC_FLAG is only relevant when not at top level and indicates whether
     648     to always allocate storage to the variable.
     649  
     650     VOLATILE_FLAG is true if this variable is declared as volatile.
     651  
     652     ARTIFICIAL_P is true if the variable was generated by the compiler.
     653  
     654     DEBUG_INFO_P is true if we need to write debug information for it.
     655  
     656     ATTR_LIST is the list of attributes to be attached to the variable.
     657  
     658     GNAT_NODE is used for the position of the decl.  */
     659  extern tree create_var_decl (tree name, tree asm_name, tree type, tree init,
     660  			     bool const_flag, bool public_flag,
     661  			     bool extern_flag, bool static_flag,
     662  			     bool volatile_flag,
     663  			     bool artificial_p, bool debug_info_p,
     664  			     struct attrib *attr_list, Node_Id gnat_node,
     665  			     bool const_decl_allowed_p = true);
     666  
     667  /* Return a FIELD_DECL node.  NAME is the field's name, TYPE is its type and
     668     RECORD_TYPE is the type of the enclosing record.  If SIZE is nonzero, it
     669     is the specified size of the field.  If POS is nonzero, it is the bit
     670     position.  PACKED is 1 if the enclosing record is packed, -1 if it has
     671     Component_Alignment of Storage_Unit.  If ADDRESSABLE is nonzero, it
     672     means we are allowed to take the address of the field; if it is negative,
     673     we should not make a bitfield, which is used by make_aligning_type.  */
     674  extern tree create_field_decl (tree name, tree type, tree record_type,
     675  			       tree size, tree pos, int packed,
     676  			       int addressable);
     677  
     678  /* Return a PARM_DECL node with NAME and TYPE.  */
     679  extern tree create_param_decl (tree name, tree type);
     680  
     681  /* Return a LABEL_DECL with NAME.  GNAT_NODE is used for the position of
     682     the decl.  */
     683  extern tree create_label_decl (tree name, Node_Id gnat_node);
     684  
     685  /* Return a FUNCTION_DECL node.  NAME is the name of the subprogram, ASM_NAME
     686     its assembler name, TYPE its type (a FUNCTION_TYPE node), PARAM_DECL_LIST
     687     the list of its parameters (a list of PARM_DECL nodes chained through the
     688     DECL_CHAIN field).
     689  
     690     INLINE_STATUS describes the inline flags to be set on the FUNCTION_DECL.
     691  
     692     PUBLIC_FLAG is true if this is for a reference to a public entity or for a
     693     definition to be made visible outside of the current compilation unit.
     694  
     695     EXTERN_FLAG is true when processing an external subprogram declaration.
     696  
     697     ARTIFICIAL_P is true if the subprogram was generated by the compiler.
     698  
     699     DEBUG_INFO_P is true if we need to write debug information for it.
     700  
     701     DEFINITION is true if the subprogram is to be considered as a definition.
     702  
     703     ATTR_LIST is the list of attributes to be attached to the subprogram.
     704  
     705     GNAT_NODE is used for the position of the decl.  */
     706  extern tree create_subprog_decl (tree name, tree asm_name, tree type,
     707  				 tree param_decl_list,
     708  				 enum inline_status_t inline_status,
     709  				 bool public_flag, bool extern_flag,
     710  				 bool artificial_p, bool debug_info_p,
     711  				 bool definition, struct attrib *attr_list,
     712  				 Node_Id gnat_node);
     713  
     714  /* Given a subprogram declaration DECL, its assembler name and its type,
     715     finish constructing the subprogram declaration from ASM_NAME and TYPE.  */
     716  extern void finish_subprog_decl (tree decl, tree asm_name, tree type);
     717  
     718  /* Process the attributes in ATTR_LIST for NODE, which is either a DECL or
     719     a TYPE.  If IN_PLACE is true, the tree pointed to by NODE should not be
     720     changed.  GNAT_NODE is used for the position of error messages.  */
     721  extern void process_attributes (tree *node, struct attrib **attr_list,
     722  				bool in_place, Node_Id gnat_node);
     723  
     724  /* Set up the framework for generating code for SUBPROG_DECL, a subprogram
     725     body. This routine needs to be invoked before processing the declarations
     726     appearing in the subprogram.  */
     727  extern void begin_subprog_body (tree subprog_decl);
     728  
     729  /* Finish translating the current subprogram and set its BODY.  */
     730  extern void end_subprog_body (tree body);
     731  
     732  /* Wrap up compilation of SUBPROG_DECL, a subprogram body.  */
     733  extern void rest_of_subprog_body_compilation (tree subprog_decl);
     734  
     735  /* Build a template of type TEMPLATE_TYPE from the array bounds of ARRAY_TYPE.
     736     EXPR is an expression that we can use to locate any PLACEHOLDER_EXPRs.
     737     Return a constructor for the template.  */
     738  extern tree build_template (tree template_type, tree array_type, tree expr);
     739  
     740  /* Build a type to be used to represent an aliased object whose nominal type
     741     is an unconstrained array.  This consists of a RECORD_TYPE containing a
     742     field of TEMPLATE_TYPE and a field of OBJECT_TYPE, which is an ARRAY_TYPE.
     743     If ARRAY_TYPE is that of an unconstrained array, this is used to represent
     744     an arbitrary unconstrained object.  Use NAME as the name of the record.
     745     DEBUG_INFO_P is true if we need to write debug information for the type.  */
     746  extern tree build_unc_object_type (tree template_type, tree object_type,
     747  				   tree name, bool debug_info_p);
     748  
     749  /* Same as build_unc_object_type, but taking a thin or fat pointer type
     750     instead of the template type.  */
     751  extern tree build_unc_object_type_from_ptr (tree thin_fat_ptr_type,
     752  					    tree object_type, tree name,
     753  					    bool debug_info_p);
     754  
     755  /* Update anything previously pointing to OLD_TYPE to point to NEW_TYPE.  In
     756     the normal case this is just two adjustments, but we have more to do
     757     if NEW is an UNCONSTRAINED_ARRAY_TYPE.  */
     758  extern void update_pointer_to (tree old_type, tree new_type);
     759  
     760  /* EXP is an expression for the size of an object.  If this size contains
     761     discriminant references, replace them with the maximum (if MAX_P) or
     762     minimum (if !MAX_P) possible value of the discriminant.  */
     763  extern tree max_size (tree exp, bool max_p);
     764  
     765  /* Remove all conversions that are done in EXP.  This includes converting
     766     from a padded type or to a left-justified modular type.  If TRUE_ADDRESS
     767     is true, always return the address of the containing object even if
     768     the address is not bit-aligned.  */
     769  extern tree remove_conversions (tree exp, bool true_address);
     770  
     771  /* If EXP's type is an UNCONSTRAINED_ARRAY_TYPE, return an expression that
     772     refers to the underlying array.  If its type has TYPE_CONTAINS_TEMPLATE_P,
     773     likewise return an expression pointing to the underlying array.  */
     774  extern tree maybe_unconstrained_array (tree exp);
     775  
     776  /* Return an expression that does an unchecked conversion of EXPR to TYPE.
     777     If NOTRUNC_P is true, truncation operations should be suppressed.  */
     778  extern tree unchecked_convert (tree type, tree expr, bool notrunc_p);
     779  
     780  /* Return the appropriate GCC tree code for the specified GNAT_TYPE,
     781     the latter being a record type as predicated by Is_Record_Type.  */
     782  extern enum tree_code tree_code_for_record_type (Entity_Id gnat_type);
     783  
     784  /* Return true if GNAT_TYPE is a "double" floating-point type, i.e. whose
     785     size is equal to 64 bits, or an array of such a type.  Set ALIGN_CLAUSE
     786     according to the presence of an alignment clause on the type or, if it
     787     is an array, on the component type.  */
     788  extern bool is_double_float_or_array (Entity_Id gnat_type,
     789  				      bool *align_clause);
     790  
     791  /* Return true if GNAT_TYPE is a "double" or larger scalar type, i.e. whose
     792     size is greater or equal to 64 bits, or an array of such a type.  Set
     793     ALIGN_CLAUSE according to the presence of an alignment clause on the
     794     type or, if it is an array, on the component type.  */
     795  extern bool is_double_scalar_or_array (Entity_Id gnat_type,
     796  				       bool *align_clause);
     797  
     798  /* Return true if GNU_TYPE is suitable as the type of a non-aliased
     799     component of an aggregate type.  */
     800  extern bool type_for_nonaliased_component_p (tree gnu_type);
     801  
     802  /* Return true if TYPE is a smaller form of ORIG_TYPE.  */
     803  extern bool smaller_form_type_p (tree type, tree orig_type);
     804  
     805  /* Return the base type of TYPE.  */
     806  extern tree get_base_type (tree type);
     807  
     808  /* EXP is a GCC tree representing an address.  See if we can find how
     809     strictly the object at that address is aligned.   Return that alignment
     810     strictly the object at that address is aligned.   Return that alignment
     811     in bits.  If we don't know anything about the alignment, return 0.  */
     812  extern unsigned int known_alignment (tree exp);
     813  
     814  /* Return true if TYPE is a type with variable size or a padding type with a
     815     field of variable size or a record that has a field with such a type.  */
     816  extern bool type_has_variable_size (tree type);
     817  
     818  /* Return true if VALUE is a multiple of FACTOR. FACTOR must be a power
     819     of 2.  */
     820  extern bool value_factor_p (tree value, unsigned HOST_WIDE_INT factor);
     821  
     822  /* Build an atomic load for the underlying atomic object in SRC.  SYNC is
     823     true if the load requires synchronization.  */
     824  extern tree build_atomic_load (tree src, bool sync);
     825  
     826  /* Build an atomic store from SRC to the underlying atomic object in DEST.
     827     SYNC is true if the store requires synchronization.  */
     828  extern tree build_atomic_store (tree dest, tree src, bool sync);
     829  
     830  /* Build a load-modify-store sequence from SRC to DEST.  GNAT_NODE is used for
     831     the location of the sequence.  Note that, even if the load and the store are
     832     both atomic, the sequence itself is not atomic.  */
     833  extern tree build_load_modify_store (tree dest, tree src, Node_Id gnat_node);
     834  
     835  /* Make a binary operation of kind OP_CODE.  RESULT_TYPE is the type
     836     desired for the result.  Usually the operation is to be performed
     837     in that type.  For MODIFY_EXPR and ARRAY_REF, RESULT_TYPE may be 0
     838     in which case the type to be used will be derived from the operands.
     839     Don't fold the result if NO_FOLD is true.  */
     840  extern tree build_binary_op (enum tree_code op_code, tree result_type,
     841  			     tree left_operand, tree right_operand,
     842  			     bool no_fold=false);
     843  
     844  /* Similar, but make unary operation.  */
     845  extern tree build_unary_op (enum tree_code op_code, tree result_type,
     846                              tree operand);
     847  
     848  /* Similar, but for COND_EXPR.  */
     849  extern tree build_cond_expr (tree result_type, tree condition_operand,
     850                               tree true_operand, tree false_operand);
     851  
     852  /* Similar, but for COMPOUND_EXPR.  */
     853  extern tree build_compound_expr (tree result_type, tree stmt_operand,
     854  				 tree expr_operand);
     855  
     856  /* Conveniently construct a function call expression.  FNDECL names the
     857     function to be called, N is the number of arguments, and the "..."
     858     parameters are the argument expressions.  Unlike build_call_expr
     859     this doesn't fold the call, hence it will always return a CALL_EXPR.  */
     860  extern tree build_call_n_expr (tree fndecl, int n, ...);
     861  
     862  /* Build a call to a function that raises an exception and passes file name
     863     and line number, if requested.  MSG says which exception function to call.
     864     GNAT_NODE is the node conveying the source location for which the error
     865     should be signaled, or Empty in which case the error is signaled for the
     866     current location.  KIND says which kind of exception node this is for,
     867     among N_Raise_{Constraint,Storage,Program}_Error.  */
     868  extern tree build_call_raise (int msg, Node_Id gnat_node, char kind);
     869  
     870  /* Similar to build_call_raise, with extra information about the column
     871     where the check failed.  */
     872  extern tree build_call_raise_column (int msg, Node_Id gnat_node, char kind);
     873  
     874  /* Similar to build_call_raise_column, for an index or range check exception ,
     875     with extra information of the form "INDEX out of range FIRST..LAST".  */
     876  extern tree build_call_raise_range (int msg, Node_Id gnat_node, char kind,
     877  				    tree index, tree first, tree last);
     878  
     879  /* Return a CONSTRUCTOR of TYPE whose elements are V.  This is not the
     880     same as build_constructor in the language-independent tree.cc.  */
     881  extern tree gnat_build_constructor (tree type, vec<constructor_elt, va_gc> *v);
     882  
     883  /* Return a COMPONENT_REF to access FIELD in RECORD, or NULL_EXPR and generate
     884     a Constraint_Error if the field is not found in the record.  Don't fold the
     885     result if NO_FOLD is true.  */
     886  extern tree build_component_ref (tree record, tree field, bool no_fold);
     887  
     888  /* Build a GCC tree to call an allocation or deallocation function.
     889     If GNU_OBJ is nonzero, it is an object to deallocate.  Otherwise,
     890     generate an allocator.
     891  
     892     GNU_SIZE is the number of bytes to allocate and GNU_TYPE is the contained
     893     object type, used to determine the to-be-honored address alignment.
     894     GNAT_PROC, if present, is a procedure to call and GNAT_POOL is the storage
     895     pool to use.  If not present, malloc and free are used.  GNAT_NODE is used
     896     to provide an error location for restriction violation messages.  */
     897  extern tree build_call_alloc_dealloc (tree gnu_obj, tree gnu_size,
     898                                        tree gnu_type, Entity_Id gnat_proc,
     899  				      Entity_Id gnat_pool, Node_Id gnat_node);
     900  
     901  /* Build a GCC tree to correspond to allocating an object of TYPE whose
     902     initial value if INIT, if INIT is nonzero.  Convert the expression to
     903     RESULT_TYPE, which must be some type of pointer.  Return the tree.
     904  
     905     GNAT_PROC and GNAT_POOL optionally give the procedure to call and
     906     the storage pool to use.  GNAT_NODE is used to provide an error
     907     location for restriction violation messages.  If IGNORE_INIT_TYPE is
     908     true, ignore the type of INIT for the purpose of determining the size;
     909     this will cause the maximum size to be allocated if TYPE is of
     910     self-referential size.  */
     911  extern tree build_allocator (tree type, tree init, tree result_type,
     912                               Entity_Id gnat_proc, Entity_Id gnat_pool,
     913                               Node_Id gnat_node, bool);
     914  
     915  /* Build a load of SRC using the storage model of GNAT_SMO.  */
     916  extern tree build_storage_model_load (Entity_Id gnat_smo, tree src);
     917  
     918  /* Build a load of SRC into DEST using the storage model of GNAT_SMO.
     919     If SIZE is specified, use it, otherwise use the size of SRC.  */
     920  extern tree build_storage_model_load (Entity_Id gnat_smo, tree dest, tree src,
     921  				      tree size = NULL_TREE);
     922  
     923  /* Build a store of SRC into DEST using the storage model of GNAT_SMO.
     924     If SIZE is specified, use it, otherwise use the size of DEST.  */
     925  extern tree build_storage_model_store (Entity_Id gnat_smo, tree dest, tree src,
     926  				       tree size = NULL_TREE);
     927  
     928  /* Given a tree EXP, instantiate occurrences of LOAD_EXPR in it and associate
     929     them with the storage model of GNAT_SMO.  */
     930  extern tree instantiate_load_in_expr (tree exp, Entity_Id gnat_smo);
     931  
     932  /* This macro calls the above function but short-circuits the common
     933     case of a constant to save time and also checks for NULL.  */
     934  
     935  #define INSTANTIATE_LOAD_IN_EXPR(EXP, GNAT_SMO) \
     936    ((EXP) == NULL_TREE || TREE_CONSTANT (EXP) ? (EXP)	\
     937     : instantiate_load_in_expr (EXP, GNAT_SMO))
     938  
     939  /* Given an array or slice reference, instantiate occurrences of LOAD_EXPR in
     940     it and associate them with the storage model of GNAT_SMO.  */
     941  extern void instantiate_load_in_array_ref (tree ref, Entity_Id gnat_smo);
     942  
     943  /* Indicate that we need to take the address of T and that it therefore
     944     should not be allocated in a register.  Returns true if successful.  */
     945  extern bool gnat_mark_addressable (tree t);
     946  
     947  /* Save EXP for later use or reuse.  This is equivalent to save_expr in tree.cc
     948     but we know how to handle our own nodes.  */
     949  extern tree gnat_save_expr (tree exp);
     950  
     951  /* Protect EXP for immediate reuse.  This is a variant of gnat_save_expr that
     952     is optimized under the assumption that EXP's value doesn't change before
     953     its subsequent reuse(s) except through its potential reevaluation.  */
     954  extern tree gnat_protect_expr (tree exp);
     955  
     956  /* This is equivalent to stabilize_reference in tree.cc but we know how to
     957     handle our own nodes and we take extra arguments.  FORCE says whether to
     958     force evaluation of everything in REF.  INIT is set to the first arm of
     959     a COMPOUND_EXPR present in REF, if any.  */
     960  extern tree gnat_stabilize_reference (tree ref, bool force, tree *init);
     961  
     962  /* Rewrite reference REF and call FUNC on each expression within REF in the
     963     process.  DATA is passed unmodified to FUNC.  INIT is set to the first
     964     arm of a COMPOUND_EXPR present in REF, if any.  */
     965  typedef tree (*rewrite_fn) (tree, void *);
     966  extern tree gnat_rewrite_reference (tree ref, rewrite_fn func, void *data,
     967  				    tree *init);
     968  
     969  /* This is equivalent to get_inner_reference in expr.cc but it returns the
     970     ultimate containing object only if the reference (lvalue) is constant,
     971     i.e. if it doesn't depend on the context in which it is evaluated.  */
     972  extern tree get_inner_constant_reference (tree exp);
     973  
     974  /* Return true if EXPR is the addition or the subtraction of a constant and,
     975     if so, set *ADD to the addend, *CST to the constant and *MINUS_P to true
     976     if this is a subtraction.  */
     977  extern bool is_simple_additive_expression (tree expr, tree *add, tree *cst,
     978  					   bool *minus_p);
     979  
     980  /* If EXPR is an expression that is invariant in the current function, in the
     981     sense that it can be evaluated anywhere in the function and any number of
     982     times, return EXPR or an equivalent expression.  Otherwise return NULL.  */
     983  extern tree gnat_invariant_expr (tree expr);
     984  
     985  /* Implementation of the builtin_function langhook.  */
     986  extern tree gnat_builtin_function (tree decl);
     987  
     988  /* Search the chain of currently reachable declarations for a builtin
     989     FUNCTION_DECL node corresponding to function NAME (an IDENTIFIER_NODE).
     990     Return the first node found, if any, or NULL_TREE otherwise.  */
     991  extern tree builtin_decl_for (tree name);
     992  
     993  /* GNU_TYPE is a type. Determine if it should be passed by reference by
     994     default.  */
     995  extern bool default_pass_by_ref (tree gnu_type);
     996  
     997  /* GNU_TYPE is the type of a subprogram parameter.  Determine from the type
     998     if it should be passed by reference.  */
     999  extern bool must_pass_by_ref (tree gnu_type);
    1000  
    1001  /* Return the size of the FP mode with precision PREC.  */
    1002  extern int fp_prec_to_size (int prec);
    1003  
    1004  /* Return the precision of the FP mode with size SIZE.  */
    1005  extern int fp_size_to_prec (int size);
    1006  
    1007  /* Return whether GNAT_NODE is a defining identifier for a renaming that comes
    1008     from the parameter association for the instantiation of a generic.  We do
    1009     not want to emit source location for them: the code generated for their
    1010     initialization is likely to disturb debugging.  */
    1011  extern bool renaming_from_instantiation_p (Node_Id gnat_node);
    1012  
    1013  /* Try to process all nodes in the deferred context queue.  Keep in the queue
    1014     the ones that cannot be processed yet, remove the other ones.  If FORCE is
    1015     true, force the processing for all nodes, use the global context when nodes
    1016     don't have a GNU translation.  */
    1017  extern void process_deferred_decl_context (bool force);
    1018  
    1019  /* Return the innermost scope, starting at GNAT_NODE, we are be interested in
    1020     the debug info, or Empty if there is no such scope.  If not NULL, set
    1021     IS_SUBPROGRAM to whether the returned entity is a subprogram.  */
    1022  extern Entity_Id get_debug_scope (Node_Id gnat_node, bool *is_subprogram);
    1023  
    1024  /* Return whether EXPR, which is the renamed object in an object renaming
    1025     declaration, can be materialized as a reference (REFERENCE_TYPE).  This
    1026     should be synchronized with Exp_Dbug.Debug_Renaming_Declaration.  */
    1027  extern bool can_materialize_object_renaming_p (Node_Id expr);
    1028  
    1029  /* Return whether GNAT_ENTITY is a simple constant, i.e. it represents only
    1030     its value and reading it has no side effects.  */
    1031  extern bool simple_constant_p (Entity_Id gnat_entity);
    1032  
    1033  /* Return the size of TYPE, which must be a positive power of 2.  */
    1034  extern unsigned int resolve_atomic_size (tree type);
    1035  
    1036  #ifdef __cplusplus
    1037  extern "C" {
    1038  #endif
    1039  
    1040  /* These functions return the basic data type sizes and related parameters
    1041     about the target machine.  */
    1042  extern Pos get_target_bits_per_unit (void);
    1043  extern Pos get_target_bits_per_word (void);
    1044  extern Pos get_target_char_size (void);
    1045  extern Pos get_target_wchar_t_size (void);
    1046  extern Pos get_target_short_size (void);
    1047  extern Pos get_target_int_size (void);
    1048  extern Pos get_target_long_size (void);
    1049  extern Pos get_target_long_long_size (void);
    1050  extern Pos get_target_long_long_long_size (void);
    1051  extern Pos get_target_pointer_size (void);
    1052  extern Pos get_target_maximum_default_alignment (void);
    1053  extern Pos get_target_system_allocator_alignment (void);
    1054  extern Pos get_target_maximum_allowed_alignment (void);
    1055  extern Pos get_target_maximum_alignment (void);
    1056  extern Nat get_target_float_words_be (void);
    1057  extern Nat get_target_words_be (void);
    1058  extern Nat get_target_bytes_be (void);
    1059  extern Nat get_target_bits_be (void);
    1060  extern Nat get_target_strict_alignment (void);
    1061  extern Nat get_target_double_float_alignment (void);
    1062  extern Nat get_target_double_scalar_alignment (void);
    1063  
    1064  /* This function is called by the front-end to enumerate all the supported
    1065     modes for the machine, as well as some predefined C types.  */
    1066  extern void enumerate_modes (void (*f) (const char *, int, int, int, int, int,
    1067  					int, int));
    1068  
    1069  #ifdef __cplusplus
    1070  }
    1071  #endif
    1072  
    1073  /* Use gigi_checking_assert to test invariants in code generation mode.
    1074     It's effective only if the compiler is configured with more checking
    1075     than the release mode and can be disabled by means of -fchecking.  */
    1076  #define gigi_checking_assert(EXPR) \
    1077    gcc_checking_assert ((EXPR) || type_annotate_only)
    1078  
    1079  /* Return the smallest power of 2 larger than X.  */
    1080  
    1081  static inline unsigned HOST_WIDE_INT
    1082  ceil_pow2 (unsigned HOST_WIDE_INT x)
    1083  {
    1084    return (unsigned HOST_WIDE_INT) 1 << ceil_log2 (x);
    1085  }
    1086  
    1087  /* Return true if EXP, a CALL_EXPR, is an atomic load.  */
    1088  
    1089  static inline bool
    1090  call_is_atomic_load (tree exp)
    1091  {
    1092    tree fndecl = get_callee_fndecl (exp);
    1093  
    1094    if (!(fndecl && fndecl_built_in_p (fndecl, BUILT_IN_NORMAL)))
    1095      return false;
    1096  
    1097    enum built_in_function code = DECL_FUNCTION_CODE (fndecl);
    1098    return BUILT_IN_ATOMIC_LOAD_N <= code && code <= BUILT_IN_ATOMIC_LOAD_16;
    1099  }
    1100  
    1101  /* Return true if TYPE is padding a self-referential type.  */
    1102  
    1103  static inline bool
    1104  type_is_padding_self_referential (tree type)
    1105  {
    1106    if (!TYPE_IS_PADDING_P (type))
    1107      return false;
    1108  
    1109    return CONTAINS_PLACEHOLDER_P (DECL_SIZE (TYPE_FIELDS (type)));
    1110  }
    1111  
    1112  /* Return true if a function returning TYPE doesn't return a fixed size.  */
    1113  
    1114  static inline bool
    1115  return_type_with_variable_size_p (tree type)
    1116  {
    1117    if (TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
    1118      return true;
    1119  
    1120    /* Return true for an unconstrained type with default discriminant, see
    1121       the E_Subprogram_Type case of gnat_to_gnu_entity.  */
    1122    if (type_is_padding_self_referential (type))
    1123      return true;
    1124  
    1125    return false;
    1126  }
    1127  
    1128  /* Return the unsigned version of TYPE_NODE, a scalar type.  */
    1129  
    1130  static inline tree
    1131  gnat_unsigned_type_for (tree type_node)
    1132  {
    1133    return gnat_signed_or_unsigned_type_for (1, type_node);
    1134  }
    1135  
    1136  /* Return the signed version of TYPE_NODE, a scalar type.  */
    1137  
    1138  static inline tree
    1139  gnat_signed_type_for (tree type_node)
    1140  {
    1141    return gnat_signed_or_unsigned_type_for (0, type_node);
    1142  }
    1143  
    1144  /* Like build_qualified_type, but TYPE_QUALS is added to the existing
    1145     qualifiers on TYPE.  */
    1146  
    1147  static inline tree
    1148  change_qualified_type (tree type, int type_quals)
    1149  {
    1150    /* Qualifiers must be put on the associated array type.  */
    1151    if (TREE_CODE (type) == UNCONSTRAINED_ARRAY_TYPE)
    1152      return type;
    1153  
    1154    return build_qualified_type (type, TYPE_QUALS (type) | type_quals);
    1155  }
    1156  
    1157  /* If EXPR's type is a VECTOR_TYPE, return EXPR converted to the associated
    1158     TYPE_REPRESENTATIVE_ARRAY.  */
    1159  
    1160  static inline tree
    1161  maybe_vector_array (tree expr)
    1162  {
    1163    tree type = TREE_TYPE (expr);
    1164  
    1165    if (VECTOR_TYPE_P (type))
    1166      expr = convert (TYPE_REPRESENTATIVE_ARRAY (type), expr);
    1167  
    1168    return expr;
    1169  }
    1170  
    1171  /* Adjust the character type TYPE if need be.  */
    1172  
    1173  static inline tree
    1174  maybe_character_type (tree type)
    1175  {
    1176    if (TREE_CODE (type) == INTEGER_TYPE
    1177        && TYPE_STRING_FLAG (type)
    1178        && !TYPE_UNSIGNED (type))
    1179      type = gnat_unsigned_type_for (type);
    1180  
    1181    return type;
    1182  }
    1183  
    1184  /* Adjust the character value EXPR if need be.  */
    1185  
    1186  static inline tree
    1187  maybe_character_value (tree expr)
    1188  {
    1189    tree type = TREE_TYPE (expr);
    1190  
    1191    if (TREE_CODE (type) == INTEGER_TYPE
    1192        && TYPE_STRING_FLAG (type)
    1193        && !TYPE_UNSIGNED (type))
    1194      {
    1195        type = gnat_unsigned_type_for (type);
    1196        expr = convert (type, expr);
    1197      }
    1198  
    1199    return expr;
    1200  }
    1201  
    1202  /* Return the debug type of TYPE if it exists, otherwise TYPE itself.  */
    1203  
    1204  static inline tree
    1205  maybe_debug_type (tree type)
    1206  {
    1207    if (TYPE_CAN_HAVE_DEBUG_TYPE_P (type) && TYPE_DEBUG_TYPE (type))
    1208      type = TYPE_DEBUG_TYPE (type);
    1209  
    1210    return type;
    1211  }
    1212  
    1213  /* Remove the padding around EXPR if need be.  */
    1214  
    1215  static inline tree
    1216  maybe_padded_object (tree expr)
    1217  {
    1218    tree type = TREE_TYPE (expr);
    1219  
    1220    if (TYPE_IS_PADDING_P (type))
    1221      expr = convert (TREE_TYPE (TYPE_FIELDS (type)), expr);
    1222  
    1223    return expr;
    1224  }
    1225  
    1226  /* Return the type of operand #0 of EXPR.  */
    1227  
    1228  static inline tree
    1229  operand_type (tree expr)
    1230  {
    1231    return TREE_TYPE (TREE_OPERAND (expr, 0));
    1232  }
    1233  
    1234  /* Return the third value of a list.  */
    1235  
    1236  static inline tree
    1237  list_third (tree list)
    1238  {
    1239    return TREE_VALUE (TREE_CHAIN (TREE_CHAIN (list)));
    1240  }