| blob | 46848f230f72578a5de0a794cb7fdf6fb752ca90 |
1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * T R A N S *
6 * *
7 * C Implementation File *
8 * *
9 * Copyright (C) 1992-2010, 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 ****************************************************************************/
56 /* We should avoid allocating more than ALLOCA_THRESHOLD bytes via alloca,
57 for fear of running out of stack space. If we need more, we use xmalloc
58 instead. */
59 #define ALLOCA_THRESHOLD 1000
61 /* Let code below know whether we are targetting VMS without need of
62 intrusive preprocessor directives. */
63 #ifndef TARGET_ABI_OPEN_VMS
64 #define TARGET_ABI_OPEN_VMS 0
65 #endif
67 /* For efficient float-to-int rounding, it is necessary to know whether
68 floating-point arithmetic may use wider intermediate results. When
69 FP_ARITH_MAY_WIDEN is not defined, be conservative and only assume
70 that arithmetic does not widen if double precision is emulated. */
71 #ifndef FP_ARITH_MAY_WIDEN
72 #if defined(HAVE_extendsfdf2)
73 #define FP_ARITH_MAY_WIDEN HAVE_extendsfdf2
74 #else
75 #define FP_ARITH_MAY_WIDEN 0
76 #endif
77 #endif
79 /* Pointers to front-end tables accessed through macros. */
89 /* Highest number in the front-end node table. */
92 /* Current node being treated, in case abort called. */
93 Node_Id error_gnat_node;
95 /* True when gigi is being called on an analyzed but unexpanded
96 tree, and the only purpose of the call is to properly annotate
97 types with representation information. */
100 /* Current filename without path. */
103 /* When not optimizing, we cache the 'First, 'Last and 'Length attributes
104 of unconstrained array IN parameters to avoid emitting a great deal of
105 redundant instructions to recompute them each time. */
109 tree first;
110 tree last;
111 tree length;
112 };
121 };
123 #define f_parm_attr_cache \
124 DECL_STRUCT_FUNCTION (current_function_decl)->language->parm_attr_cache
126 /* A structure used to gather together information about a statement group.
127 We use this to gather related statements, for example the "then" part
128 of a IF. In the case where it represents a lexical scope, we may also
129 have a BLOCK node corresponding to it and/or cleanups. */
136 };
140 /* List of unused struct stmt_group nodes. */
143 /* A structure used to record information on elaboration procedures
144 we've made and need to process.
146 ??? gnat_node should be Node_Id, but gengtype gets confused. */
152 };
156 /* Stack of exception pointer variables. Each entry is the VAR_DECL
157 that stores the address of the raised exception. Nonzero means we
158 are in an exception handler. Not used in the zero-cost case. */
161 /* Stack for storing the current elaboration procedure decl. */
164 /* Stack of labels to be used as a goto target instead of a return in
165 some functions. See processing for N_Subprogram_Body. */
168 /* Stack of LOOP_STMT nodes. */
171 /* The stacks for N_{Push,Pop}_*_Label. */
176 /* Map GNAT tree codes to GCC tree codes for simple expressions. */
207 /* Hooks for debug info back-ends, only supported and used in a restricted set
208 of configurations. */
211 \f
212 /* This is the main program of the back-end. It sets up all the table
213 structures and then generates code. */
215 void
225 {
226 Entity_Id gnat_literal;
247 /* Declare the name of the compilation unit as the first global
248 name in order to make the middle-end fully deterministic. */
253 {
254 /* Use the identifier table to make a permanent copy of the filename as
255 the name table gets reallocated after Gigi returns but before all the
256 debugging information is output. The __gnat_to_canonical_file_spec
257 call translates filenames from pragmas Source_Reference that contain
258 host style syntax not understood by gdb. */
260 = IDENTIFIER_POINTER
261 (get_identifier
262 (__gnat_to_canonical_file_spec
265 /* We rely on the order isomorphism between files and line maps. */
268 /* We create the line map for a source file at once, with a fixed number
269 of columns chosen to avoid jumping over the next power of 2. */
274 }
276 /* Initialize ourselves. */
281 /* If we are just annotating types, give VOID_TYPE zero sizes to avoid
282 errors. */
284 {
287 }
289 /* If the GNU type extensions to DWARF are available, setup the hooks. */
290 #if defined (DWARF2_DEBUGGING_INFO) && defined (DWARF2_GNU_TYPE_EXTENSIONS)
291 /* We condition the name demangling and the generation of type encoding
292 strings on -gdwarf+ and always set descriptive types on. */
294 {
297 }
299 #endif
301 /* Enable GNAT stack checking method if needed */
305 /* Retrieve alignment settings. */
309 /* Record the builtin types. Define `integer' and `character' first so that
310 dbx will output them first. */
316 /* Save the type we made for integer as the type for Standard.Integer. */
321 /* Likewise for character as the type for Standard.Character. */
326 /* Likewise for boolean as the type for Standard.Boolean. */
350 /* Now declare run-time functions. */
353 /* malloc is a function declaration tree for a function to allocate
354 memory. */
355 malloc_decl
363 /* malloc32 is a function declaration tree for a function to allocate
364 32-bit memory on a 64-bit system. Needed only on 64-bit VMS. */
365 malloc32_decl
373 /* free is a function declaration tree for a function to free memory. */
374 free_decl
378 ptr_void_type_node,
379 t)),
382 /* This is used for 64-bit multiplication with overflow checking. */
383 mulv64_decl
389 /* Name of the _Parent field in tagged record types. */
392 /* Name of the Exception_Data type defined in System.Standard_Library. */
393 exception_data_name_id
396 /* Make the types and functions used for exception processing. */
397 jmpbuf_type
403 /* Functions to get and set the jumpbuf pointer for the current thread. */
404 get_jmpbuf_decl
405 = create_subprog_decl
409 /* Avoid creating superfluous edges to __builtin_setjmp receivers. */
413 set_jmpbuf_decl
414 = create_subprog_decl
416 NULL_TREE,
422 /* setjmp returns an integer and has one operand, which is a pointer to
423 a jmpbuf. */
424 setjmp_decl
425 = create_subprog_decl
433 /* update_setjmp_buf updates a setjmp buffer from the current stack pointer
434 address. */
435 update_setjmp_buf_decl
436 = create_subprog_decl
444 /* Hooks to call when entering/leaving an exception handler. */
445 begin_handler_decl
449 ptr_void_type_node,
450 t)),
454 end_handler_decl
458 ptr_void_type_node,
459 t)),
463 /* If in no exception handlers mode, all raise statements are redirected to
464 __gnat_last_chance_handler. No need to redefine raise_nodefer_decl since
465 this procedure will never be called in this mode. */
467 {
468 tree decl
469 = create_subprog_decl
473 build_pointer_type
476 integer_type_node,
477 t))),
482 }
483 else
484 /* Otherwise, make one decl for each exception reason. */
486 {
491 = create_subprog_decl
495 build_pointer_type
498 integer_type_node,
499 t))),
501 }
504 {
509 TYPE_QUAL_VOLATILE);
510 }
512 /* Set the types that GCC and Gigi use from the front end. */
513 exception_type
517 /* Make other functions used for exception processing. */
518 get_excptr_decl
519 = create_subprog_decl
521 NULL_TREE,
524 /* Avoid creating superfluous edges to __builtin_setjmp receivers. */
527 raise_nodefer_decl
528 = create_subprog_decl
533 t)),
536 /* Indicate that these never return. */
541 TYPE_QUAL_VOLATILE);
543 /* Build the special descriptor type and its null node if needed. */
545 {
554 TARGET_VTABLE_USES_DESCRIPTORS);
559 {
560 tree field
567 elt--;
568 }
573 }
575 long_long_float_type
579 {
580 /* In this case, the builtin floating point types are VAX float,
581 so make up a type for use. */
586 }
587 else
590 /* Dummy objects to materialize "others" and "all others" in the exception
591 tables. These are exported by a-exexpr.adb, so see this unit for the
592 types to use. */
593 others_decl
598 all_others_decl
605 /* Install the builtins we might need, either internally or as
606 user available facilities for Intrinsic imports. */
614 /* Process any Pragma Ident for the main unit. */
615 #ifdef ASM_OUTPUT_IDENT
617 ASM_OUTPUT_IDENT
620 #endif
622 /* If we are using the GCC exception mechanism, let GCC know. */
626 /* Now translate the compilation unit proper. */
629 /* Finally see if we have any elaboration procedures to deal with. */
631 {
634 /* We should have a BIND_EXPR but it may not have any statements in it.
635 If it doesn't have any, we have nothing to do except for setting the
636 flag on the GNAT node. Otherwise, process the function as others. */
642 else
643 {
646 }
647 }
649 /* We cannot track the location of errors past this point. */
651 }
652 \f
653 /* Return a positive value if an lvalue is required for GNAT_NODE, which is
654 an N_Attribute_Reference. */
656 static int
658 {
660 {
695 }
696 }
698 /* Return a positive value if an lvalue is required for GNAT_NODE. GNU_TYPE
699 is the type that will be used for GNAT_NODE in the translated GNU tree.
700 CONSTANT indicates whether the underlying object represented by GNAT_NODE
701 is constant in the Ada sense. If it is, ADDRESS_OF_CONSTANT indicates
702 whether its value is the address of a constant and ALIASED whether it is
703 aliased. If it isn't, ADDRESS_OF_CONSTANT and ALIASED are ignored.
705 The function climbs up the GNAT tree starting from the node and returns 1
706 upon encountering a node that effectively requires an lvalue downstream.
707 It returns int instead of bool to facilitate usage in non-purely binary
708 logic contexts. */
710 static int
713 {
717 {
727 /* If the parameter is by reference, an lvalue is required. */
733 /* Only the array expression can require an lvalue. */
737 /* ??? Consider that referencing an indexed component with a
738 non-constant index forces the whole aggregate to memory.
739 Note that N_Integer_Literal is conservative, any static
740 expression in the RM sense could probably be accepted. */
747 /* ... fall through ... */
750 /* Only the array expression can require an lvalue. */
764 /* We need to make a real renaming only if the constant object is
765 aliased or if we may use a renaming pointer; otherwise we can
766 optimize and return the rvalue. We make an exception if the object
767 is an identifier since in this case the rvalue can be propagated
768 attached to the CONST_DECL. */
770 || aliased
771 /* This should match the constant case of the renaming code. */
772 || Is_Composite_Type
777 /* We cannot use a constructor if this is an atomic object because
778 the actual assignment might end up being done component-wise. */
782 /* We don't use a constructor if this is a class-wide object
783 because the effective type of the object is the equivalent
784 type of the class-wide subtype and it smashes most of the
785 data into an array of bytes to which we cannot convert. */
790 /* We cannot use a constructor if the LHS is an atomic object because
791 the actual assignment might end up being done component-wise. */
799 /* We must look through all conversions for composite types because we
800 may need to bypass an intermediate conversion to a narrower record
801 type that is generated for a formal conversion, e.g. the conversion
802 to the root type of a hierarchy of tagged types generated for the
803 formal conversion to the class-wide type. */
807 /* ... fall through ... */
816 /* We should only reach here through the N_Qualified_Expression case
817 and, therefore, only for composite types. Force an lvalue since
818 a block-copy to the newly allocated area of memory is made. */
822 /* We look through dereferences for address of constant because we need
823 to handle the special cases listed above. */
829 /* ... fall through ... */
833 }
836 }
838 /* Subroutine of gnat_to_gnu to translate gnat_node, an N_Identifier,
839 to a GCC tree, which is returned. GNU_RESULT_TYPE_P is a pointer
840 to where we should place the result type. */
842 static tree
844 {
848 /* Whether we should require an lvalue for GNAT_NODE. Needed in
849 specific circumstances only, so evaluated lazily. < 0 means
850 unknown, > 0 means known true, 0 means known false. */
853 /* If GNAT_NODE is a constant, whether we should use the initialization
854 value instead of the constant entity, typically for scalars with an
855 address clause when the parent doesn't require an lvalue. */
858 /* If the Etype of this node does not equal the Etype of the Entity,
859 something is wrong with the entity map, probably in generic
860 instantiation. However, this does not apply to types. Since we sometime
861 have strange Ekind's, just do this test for objects. Also, if the Etype of
862 the Entity is private, the Etype of the N_Identifier is allowed to be the
863 full type and also we consider a packed array type to be the same as the
864 original type. Similarly, a class-wide type is equivalent to a subtype of
865 itself. Finally, if the types are Itypes, one may be a copy of the other,
866 which is also legal. */
889 /* If this is a reference to a deferred constant whose partial view is an
890 unconstrained private type, the proper type is on the full view of the
891 constant, not on the full view of the type, which may be unconstrained.
893 This may be a reference to a type, for example in the prefix of the
894 attribute Position, generated for dispatching code (see Make_DT in
895 exp_disp,adb). In that case we need the type itself, not is parent,
896 in particular if it is a derived type */
901 {
904 }
905 else
906 {
907 /* We want to use the Actual_Subtype if it has already been elaborated,
908 otherwise the Etype. Avoid using Actual_Subtype for packed arrays to
909 simplify things. */
917 else
919 }
921 /* Expand the type of this identifier first, in case it is an enumeral
922 literal, which only get made when the type is expanded. There is no
923 order-of-elaboration issue here. */
926 /* If this is a non-imported scalar constant with an address clause,
927 retrieve the value instead of a pointer to be dereferenced unless
928 an lvalue is required. This is generally more efficient and actually
929 required if this is a static expression because it might be used
930 in a context where a dereference is inappropriate, such as a case
931 statement alternative or a record discriminant. There is no possible
932 volatile-ness short-circuit here since Volatile constants must bei
933 imported per C.6. */
938 {
942 }
945 {
946 /* If this is a deferred constant, the initializer is attached to
947 the full view. */
952 }
953 else
956 /* If we are in an exception handler, force this variable into memory to
957 ensure optimization does not remove stores that appear redundant but are
958 actually needed in case an exception occurs.
960 ??? Note that we need not do this if the variable is declared within the
961 handler, only if it is referenced in the handler and declared in an
962 enclosing block, but we have no way of testing that right now.
964 ??? We used to essentially set the TREE_ADDRESSABLE flag on the variable
965 here, but it can now be removed by the Tree aliasing machinery if the
966 address of the variable is never taken. All we can do is to make the
967 variable volatile, which might incur the generation of temporaries just
968 to access the memory in some circumstances. This can be avoided for
969 variables of non-constant size because they are automatically allocated
970 to memory. There might be no way of allocating a proper temporary for
971 them in any case. We only do this for SJLJ though. */
977 /* Some objects (such as parameters passed by reference, globals of
978 variable size, and renamed objects) actually represent the address
979 of the object. In that case, we must do the dereference. Likewise,
980 deal with parameters to foreign convention subprograms. */
985 {
987 tree renamed_obj;
991 gnu_result
994 gnu_result));
996 /* If it's a renaming pointer and we are at the right binding level,
997 we can reference the renamed object directly, since the renamed
998 expression has been protected against multiple evaluations. */
1005 /* Return the underlying CST for a CONST_DECL like a few lines below,
1006 after dereferencing in this case. */
1011 else
1016 }
1018 /* The GNAT tree has the type of a function as the type of its result. Also
1019 use the type of the result if the Etype is a subtype which is nominally
1020 unconstrained. But remove any padding from the resulting type. */
1023 {
1027 }
1029 /* If we have a constant declaration and its initializer, try to return the
1030 latter to avoid the need to call fold in lots of places and the need for
1031 elaboration code if this identifier is used as an initializer itself. */
1035 {
1041 /* If there is a (corresponding) variable or this is the address of a
1042 constant, we only want to return the initializer if an lvalue isn't
1043 required. Evaluate this now if we have not already done so. */
1045 require_lvalue
1049 /* ??? We need to unshare the initializer if the object is external
1050 as such objects are not marked for unsharing if we are not at the
1051 global level. This should be fixed in add_decl_expr. */
1054 }
1059 }
1060 \f
1061 /* Subroutine of gnat_to_gnu to process gnat_node, an N_Pragma. Return
1062 any statements we generate. */
1064 static tree
1066 {
1067 Node_Id gnat_temp;
1070 /* Check for (and ignore) unrecognized pragma and do nothing if we are just
1071 annotating types. */
1077 {
1079 /* Do nothing at top level: all such variables are already viewable. */
1086 {
1092 #ifdef ASM_COMMENT_START
1094 #endif
1099 /* Use the value only if it fits into a normal register,
1100 otherwise use the address. */
1109 #ifdef ASM_COMMENT_START
1115 NULL);
1118 #endif
1120 asm_constraint,
1121 NULL_TREE,
1122 tree_cons
1130 }
1136 {
1149 }
1156 }
1159 }
1160 \f
1161 /* Subroutine of gnat_to_gnu to translate GNAT_NODE, an N_Attribute node,
1162 to a GCC tree, which is returned. GNU_RESULT_TYPE_P is a pointer to
1163 where we should place the result type. ATTRIBUTE is the attribute ID. */
1165 static tree
1167 {
1173 /* If the input is a NULL_EXPR, make a new one. */
1175 {
1179 }
1182 {
1185 /* These are just conversions since representation clauses for
1186 enumeration types are handled in the front-end. */
1187 {
1193 }
1198 /* These just add or subtract the constant 1 since representation
1199 clauses for enumeration types are handled in the front-end. */
1204 {
1206 gnu_expr
1207 = emit_check
1209 gnu_expr,
1210 attribute == Attr_Pred
1214 }
1216 gnu_result
1224 /* Conversions don't change addresses but can cause us to miss the
1225 COMPONENT_REF case below, so strip them off. */
1229 /* If we are taking 'Address of an unconstrained object, this is the
1230 pointer to the underlying array. */
1234 /* If we are building a static dispatch table, we have to honor
1235 TARGET_VTABLE_USES_DESCRIPTORS if we want to be compatible
1236 with the C++ ABI. We do it in the non-static case as well,
1237 see gnat_to_gnu_entity, case E_Access_Subprogram_Type. */
1240 {
1242 /* Descriptors can only be built here for top-level functions. */
1250 /* If we're not going to build the descriptor, we have to retrieve
1251 the one which will be built by the linker (or by the compiler
1252 later if a static chain is requested). */
1254 {
1257 gnu_result);
1259 }
1262 TARGET_VTABLE_USES_DESCRIPTORS);
1268 {
1270 {
1274 }
1275 else
1281 elt--;
1282 }
1286 }
1288 /* ... fall through ... */
1294 gnu_result
1301 /* For 'Code_Address, find an inner ADDR_EXPR and mark it so that we
1302 don't try to build a trampoline. */
1304 {
1312 }
1314 /* For other address attributes applied to a nested function,
1315 find an inner ADDR_EXPR and annotate it so that we can issue
1316 a useful warning with -Wtrampolines. */
1318 {
1322 ;
1326 {
1329 /* Check that we're not violating the No_Implicit_Dynamic_Code
1330 restriction. Be conservative if we don't know anything
1331 about the trampoline strategy for the target. */
1333 }
1334 }
1338 {
1339 tree gnu_obj_type;
1344 /* If this is an unconstrained array, we know the object has been
1345 allocated with the template in front of the object. So compute
1346 the template address. */
1348 gnu_ptr
1350 (TYPE_OBJECT_RECORD_TYPE
1352 gnu_ptr);
1357 {
1358 tree gnu_char_ptr_type
1364 }
1367 }
1376 /* Remove NOPs and conversions between original and packable version
1377 from GNU_EXPR, and conversions from GNU_PREFIX. We use GNU_EXPR
1378 to see if a COMPONENT_REF was involved. */
1383 == RECORD_TYPE
1392 /* Replace an unconstrained array type with the type of the underlying
1393 array. We can't do this with a call to maybe_unconstrained_array
1394 since we may have a TYPE_DECL. For 'Max_Size_In_Storage_Elements,
1395 use the record type that will be used to allocate the object and its
1396 template. */
1398 {
1402 }
1404 /* If we're looking for the size of a field, return the field size.
1405 Otherwise, if the prefix is an object, or if we're looking for
1406 'Object_Size or 'Max_Size_In_Storage_Elements, the result is the
1407 GCC size of the type. Otherwise, it is the RM size of the type. */
1413 {
1414 /* If the prefix is an object of a padded type, the GCC size isn't
1415 relevant to the programmer. Normally what we want is the RM size,
1416 which was set from the specified size, but if it was not set, we
1417 want the size of the field. Using the MAX of those two produces
1418 the right result in all cases. Don't use the size of the field
1419 if it's self-referential, since that's never what's wanted. */
1423 {
1427 gnu_result
1430 }
1432 {
1434 Node_Id gnat_actual_subtype
1436 tree gnu_ptr_type
1441 {
1442 tree gnu_actual_obj_type
1444 gnu_type
1446 gnu_actual_obj_type,
1449 }
1452 }
1453 else
1455 }
1456 else
1459 /* Deal with a self-referential size by returning the maximum size for
1460 a type and by qualifying the size with the object otherwise. */
1462 {
1465 else
1467 }
1469 /* If the type contains a template, subtract its size. */
1475 /* For 'Max_Size_In_Storage_Elements, adjust the unit. */
1483 {
1496 else
1497 {
1503 /* If the default alignment of "double" or larger scalar types is
1504 specifically capped and there is an alignment clause neither
1505 on the type nor on the prefix itself, return the cap. */
1507 is_capped_double
1510 is_capped_double
1512 else
1522 else
1524 }
1527 }
1536 {
1543 else
1544 gnu_result
1545 = build_binary_op
1547 build_binary_op
1559 }
1561 /* ... fall through ... */
1564 {
1571 /* Make sure any implicit dereference gets done. */
1574 /* We treat unconstrained array In parameters specially. */
1584 {
1586 tree gnu_type_temp;
1592 ;
1595 }
1602 /* When not optimizing, look up the slot associated with the parameter
1603 and the dimension in the cache and create a new one on failure. */
1605 {
1611 {
1616 }
1617 }
1619 /* Return the cached expression or build a new one. */
1621 {
1623 {
1626 }
1628 gnu_result
1630 }
1633 {
1635 {
1638 }
1640 gnu_result
1642 }
1645 {
1647 {
1650 }
1651 else
1652 {
1653 /* We used to compute the length as max (hb - lb + 1, 0),
1654 which could overflow for some cases of empty arrays, e.g.
1655 when lb == index_type'first. We now compute the length as
1656 (hb >= lb) ? hb - lb + 1 : 0, which would only overflow in
1657 much rarer cases, for extremely large arrays we expect
1658 never to encounter in practice. In addition, the former
1659 computation required the use of potentially constraining
1660 signed arithmetic while the latter doesn't. Note that
1661 the comparison must be done in the original index type,
1662 to avoid any overflow during the conversion. */
1667 gnu_result
1670 comp_type,
1674 gnu_result
1677 boolean_type_node,
1679 gnu_result,
1681 }
1682 }
1684 /* If this has a PLACEHOLDER_EXPR, qualify it by the object we are
1685 handling. Note that these attributes could not have been used on
1686 an unconstrained array type. */
1689 /* Cache the expression we have just computed. Since we want to do it
1690 at run time, we force the use of a SAVE_EXPR and let the gimplifier
1691 create the temporary. */
1693 {
1694 gnu_result
1701 else
1703 }
1705 /* Set the source location onto the predicate of the condition in the
1706 'Length case but do not do it if the expression is cached to avoid
1707 messing up the debug info. */
1712 gnat_node);
1715 }
1722 {
1723 HOST_WIDE_INT bitsize;
1724 HOST_WIDE_INT bitpos;
1725 tree gnu_offset;
1726 tree gnu_field_bitpos;
1727 tree gnu_field_offset;
1728 tree gnu_inner;
1736 /* We can have 'Bit on any object, but if it isn't a COMPONENT_REF,
1737 the result is 0. Don't allow 'Bit on a bare component, though. */
1741 {
1744 }
1746 else
1755 {
1763 {
1764 gnu_field_bitpos
1767 gnu_field_offset
1770 }
1771 }
1773 {
1776 }
1777 else
1778 {
1781 }
1784 {
1799 bitsize_one_node);
1805 }
1807 /* If this has a PLACEHOLDER_EXPR, qualify it by the object we are
1808 handling. */
1811 }
1815 {
1823 }
1849 /* Note this size cannot be self-referential. */
1856 /* This is just a zero cast to the pointer type for our prefix and
1857 dereferenced. */
1859 gnu_result
1862 integer_zero_node));
1867 {
1874 {
1879 ;
1880 }
1888 && (DECL_BY_COMPONENT_PTR_P
1892 }
1896 /* Say we have an unimplemented attribute. Then set the value to be
1897 returned to be a zero and hope that's something we can convert to
1898 the type of this attribute. */
1903 }
1905 /* If this is an attribute where the prefix was unused, force a use of it if
1906 it has a side-effect. But don't do it if the prefix is just an entity
1907 name. However, if an access check is needed, we must do it. See second
1908 example in AARM 11.6(5.e). */
1916 }
1917 \f
1918 /* Subroutine of gnat_to_gnu to translate gnat_node, an N_Case_Statement,
1919 to a GCC tree, which is returned. */
1921 static tree
1923 {
1925 Node_Id gnat_when;
1931 /* The range of values in a case statement is determined by the rules in
1932 RM 5.4(7-9). In almost all cases, this range is represented by the Etype
1933 of the expression. One exception arises in the case of a simple name that
1934 is parenthesized. This still has the Etype of the name, but since it is
1935 not a name, para 7 does not apply, and we need to go to the base type.
1936 This is the only case where parenthesization affects the dynamic
1937 semantics (i.e. the range of possible values at run time that is covered
1938 by the others alternative).
1940 Another exception is if the subtype of the expression is non-static. In
1941 that case, we also have to use the base type. */
1947 /* We build a SWITCH_EXPR that contains the code with interspersed
1948 CASE_LABEL_EXPRs for each label. */
1955 {
1957 Node_Id gnat_choice;
1959 /* First compile all the different case choices for the current WHEN
1960 alternative. */
1963 {
1967 {
1982 /* This represents either a subtype range or a static value of
1983 some kind; Ekind says which. */
1985 {
1991 }
1993 /* ... fall through ... */
2005 }
2007 /* If the case value is a subtype that raises Constraint_Error at
2008 run time because of a wrong bound, then gnu_low or gnu_high is
2009 not translated into an INTEGER_CST. In such a case, we need
2010 to ensure that the when statement is not added in the tree,
2011 otherwise it will crash the gimplifier. */
2014 {
2019 gnat_choice);
2021 }
2022 }
2024 /* Push a binding level here in case variables are declared as we want
2025 them to be local to this set of statements instead of to the block
2026 containing the Case statement. */
2028 {
2033 {
2036 }
2037 }
2038 }
2040 /* Now emit a definition of the label the cases branch to, if any. */
2047 }
2048 \f
2049 /* Return true if VAL (of type TYPE) can equal the minimum value if MAX is
2050 false, or the maximum value if MAX is true, of TYPE. */
2052 static bool
2054 {
2061 val = (max
2069 }
2071 /* Return true if VAL (of type TYPE) can equal the minimum value of TYPE.
2072 If REVERSE is true, minimum value is taken as maximum value. */
2076 {
2078 }
2080 /* Return true if VAL (of type TYPE) can equal the maximum value of TYPE.
2081 If REVERSE is true, maximum value is taken as minimum value. */
2085 {
2087 }
2089 /* Subroutine of gnat_to_gnu to translate gnat_node, an N_Loop_Statement,
2090 to a GCC tree, which is returned. */
2092 static tree
2094 {
2100 tree gnu_result;
2102 /* Set location information for statement and end label. */
2108 /* Save the end label of this LOOP_STMT in a stack so that a corresponding
2109 N_Exit_Statement can find it. */
2112 /* Set the condition under which the loop must keep going.
2113 For the case "LOOP .... END LOOP;" the condition is always true. */
2115 ;
2117 /* For the case "WHILE condition LOOP ..... END LOOP;" it's immediate. */
2122 /* Otherwise we have an iteration scheme and the condition is given by the
2123 bounds of the subtype of the iteration variable. */
2124 else
2125 {
2138 /* We must disable modulo reduction for the iteration variable, if any,
2139 in order for the loop comparison to be effective. */
2141 {
2147 }
2148 else
2149 {
2155 }
2157 /* We use two different strategies to translate the loop, depending on
2158 whether optimization is enabled.
2160 If it is, we try to generate the canonical form of loop expected by
2161 the loop optimizer, which is the do-while form:
2163 ENTRY_COND
2164 loop:
2165 TOP_UPDATE
2166 BODY
2167 BOTTOM_COND
2168 GOTO loop
2170 This makes it possible to bypass loop header copying and to turn the
2171 BOTTOM_COND into an inequality test. This should catch (almost) all
2172 loops with constant starting point. If we cannot, we try to generate
2173 the default form, which is:
2175 loop:
2176 TOP_COND
2177 BODY
2178 BOTTOM_UPDATE
2179 GOTO loop
2181 It will be rotated during loop header copying and an entry test added
2182 to yield the do-while form. This should catch (almost) all loops with
2183 constant ending point. If we cannot, we generate the fallback form:
2185 ENTRY_COND
2186 loop:
2187 BODY
2188 BOTTOM_COND
2189 BOTTOM_UPDATE
2190 GOTO loop
2192 which works in all cases but for which loop header copying will copy
2193 the BOTTOM_COND, thus adding a third conditional branch.
2195 If optimization is disabled, loop header copying doesn't come into
2196 play and we try to generate the loop forms with the less conditional
2197 branches directly. First, the default form, it should catch (almost)
2198 all loops with constant ending point. Then, if we cannot, we try to
2199 generate the shifted form:
2201 loop:
2202 TOP_COND
2203 TOP_UPDATE
2204 BODY
2205 GOTO loop
2207 which should catch loops with constant starting point. Otherwise, if
2208 we cannot, we generate the fallback form. */
2211 {
2212 /* We can use the do-while form if GNU_FIRST-1 doesn't overflow. */
2214 {
2219 }
2221 /* Otherwise, we can use the default form if GNU_LAST+1 doesn't. */
2223 ;
2225 /* Otherwise, use the fallback form. */
2226 else
2228 }
2229 else
2230 {
2231 /* We can use the default form if GNU_LAST+1 doesn't overflow. */
2233 ;
2235 /* Otherwise, we can use the shifted form if neither GNU_FIRST-1 nor
2236 GNU_LAST-1 does. */
2239 {
2245 }
2247 /* Otherwise, use the fallback form. */
2248 else
2250 }
2255 /* If we use the BOTTOM_COND, we can turn the test into an inequality
2256 test but we have to add an ENTRY_COND to protect the empty loop. */
2258 {
2260 gnu_cond_expr
2266 }
2268 /* Open a new nesting level that will surround the loop to declare the
2269 iteration variable. */
2273 /* Declare the iteration variable and set it to its initial value. */
2278 /* Do all the arithmetics in the base type. */
2281 /* Set either the top or bottom exit condition. */
2284 gnu_last);
2286 /* Set either the top or bottom update statement and give it the source
2287 location of the iteration for better coverage info. */
2293 gnat_iter_scheme);
2294 }
2296 /* If the loop was named, have the name point to this loop. In this case,
2297 the association is not a DECL node, but the end label of the loop. */
2301 /* Make the loop body into its own block, so any allocated storage will be
2302 released every iteration. This is needed for stack allocation. */
2307 /* If we declared a variable, then we are in a statement group for that
2308 declaration. Add the LOOP_STMT to it and make that the "loop". */
2310 {
2314 }
2316 /* If we have an outer COND_EXPR, that's our result and this loop is its
2317 "true" statement. Otherwise, the result is the LOOP_STMT. */
2319 {
2323 }
2324 else
2330 }
2331 \f
2332 /* Emit statements to establish __gnat_handle_vms_condition as a VMS condition
2333 handler for the current function. */
2335 /* This is implemented by issuing a call to the appropriate VMS specific
2336 builtin. To avoid having VMS specific sections in the global gigi decls
2337 array, we maintain the decls of interest here. We can't declare them
2338 inside the function because we must mark them never to be GC'd, which we
2339 can only do at the global level. */
2344 static void
2346 {
2347 tree establish_stmt;
2349 /* Elaborate the required decls on the first call. Check on the decl for
2350 the gnat condition handler to decide, as this is one we create so we are
2351 sure that it will be non null on subsequent calls. The builtin decl is
2352 looked up so remains null on targets where it is not implemented yet. */
2354 {
2355 vms_builtin_establish_handler_decl
2356 = builtin_decl_for
2359 gnat_vms_condition_handler_decl
2361 NULL_TREE,
2363 ptr_void_type_node,
2364 ptr_void_type_node,
2365 NULL_TREE),
2368 /* ??? DECL_CONTEXT shouldn't have been set because of DECL_EXTERNAL. */
2370 }
2372 /* Do nothing if the establish builtin is not available, which might happen
2373 on targets where the facility is not implemented. */
2377 establish_stmt
2379 build_unary_op
2381 gnat_vms_condition_handler_decl));
2384 }
2385 \f
2386 /* Subroutine of gnat_to_gnu to process gnat_node, an N_Subprogram_Body. We
2387 don't return anything. */
2389 static void
2391 {
2392 /* Defining identifier of a parameter to the subprogram. */
2393 Entity_Id gnat_param;
2394 /* The defining identifier for the subprogram body. Note that if a
2395 specification has appeared before for this body, then the identifier
2396 occurring in that specification will also be a defining identifier and all
2397 the calls to this subprogram will point to that specification. */
2398 Entity_Id gnat_subprog_id
2401 /* The FUNCTION_DECL node corresponding to the subprogram spec. */
2402 tree gnu_subprog_decl;
2403 /* Its RESULT_DECL node. */
2404 tree gnu_result_decl;
2405 /* The FUNCTION_TYPE node corresponding to the subprogram spec. */
2406 tree gnu_subprog_type;
2407 tree gnu_cico_list;
2408 tree gnu_result;
2411 /* If this is a generic object or if it has been eliminated,
2412 ignore it. */
2418 /* If this subprogram acts as its own spec, define it. Otherwise, just get
2419 the already-elaborated tree node. However, if this subprogram had its
2420 elaboration deferred, we will already have made a tree node for it. So
2421 treat it as not being defined in that case. Such a subprogram cannot
2422 have an address clause or a freeze node, so this test is safe, though it
2423 does disable some otherwise-useful error checking. */
2424 gnu_subprog_decl
2431 /* If the function returns by invisible reference, make it explicit in the
2432 function body. See gnat_to_gnu_entity, E_Subprogram_Type case. */
2434 {
2438 }
2440 /* Propagate the debug mode. */
2444 /* Set the line number in the decl to correspond to that of the body so that
2445 the line number notes are written correctly. */
2448 /* Initialize the information structure for the function. */
2456 /* If there are Out parameters, we need to ensure that the return statement
2457 properly copies them out. We do this by making a new block and converting
2458 any inner return into a goto to a label at the end of the block. */
2461 gnu_cico_list
2465 /* Get a tree corresponding to the code for the subprogram. */
2469 /* See if there are any parameters for which we don't yet have GCC entities.
2470 These must be for Out parameters for which we will be making VAR_DECL
2471 nodes here. Fill them in to TYPE_CI_CO_LIST, which must contain the empty
2472 entry as well. We can match up the entries because TYPE_CI_CO_LIST is in
2473 the order of the parameters. */
2478 {
2479 /* Skip any entries that have been already filled in; they must
2480 correspond to In Out parameters. */
2484 /* Do any needed references for padded types. */
2488 }
2490 /* On VMS, establish our condition handler to possibly turn a condition into
2491 the corresponding exception if the subprogram has a foreign convention or
2492 is exported.
2494 To ensure proper execution of local finalizations on condition instances,
2495 we must turn a condition into the corresponding exception even if there
2496 is no applicable Ada handler, and need at least one condition handler per
2497 possible call chain involving GNAT code. OTOH, establishing the handler
2498 has a cost so we want to minimize the number of subprograms into which
2499 this happens. The foreign or exported condition is expected to satisfy
2500 all the constraints. */
2508 /* Generate the code of the subprogram itself. A return statement will be
2509 present and any Out parameters will be handled there. */
2514 /* If we populated the parameter attributes cache, we need to make sure
2515 that the cached expressions are evaluated on all possible paths. */
2518 {
2525 {
2532 }
2536 }
2538 /* If we are dealing with a return from an Ada procedure with parameters
2539 passed by copy-in/copy-out, we need to return a record containing the
2540 final values of these parameters. If the list contains only one entry,
2541 return just that entry though.
2543 For a full description of the copy-in/copy-out parameter mechanism, see
2544 the part of the gnat_to_gnu_entity routine dealing with the translation
2545 of subprograms.
2547 We need to make a block that contains the definition of that label and
2548 the copying of the return value. It first contains the function, then
2549 the label and copy statement. */
2551 {
2552 tree gnu_retval;
2563 else
2565 gnu_cico_list);
2571 }
2575 /* Set the end location. */
2576 Sloc_to_locus
2584 /* Finally annotate the parameters and disconnect the trees for parameters
2585 that we have turned into variables since they are now unusable. */
2589 {
2595 }
2601 }
2602 \f
2603 /* Subroutine of gnat_to_gnu to translate gnat_node, either an N_Function_Call
2604 or an N_Procedure_Call_Statement, to a GCC tree, which is returned.
2605 GNU_RESULT_TYPE_P is a pointer to where we should place the result type.
2606 If GNU_TARGET is non-null, this must be a function call on the RHS of a
2607 N_Assignment_Statement and the result is to be placed into that object. */
2609 static tree
2611 {
2612 /* The GCC node corresponding to the GNAT subprogram name. This can either
2613 be a FUNCTION_DECL node if we are dealing with a standard subprogram call,
2614 or an indirect reference expression (an INDIRECT_REF node) pointing to a
2615 subprogram. */
2617 /* The FUNCTION_TYPE node giving the GCC type of the subprogram. */
2620 Entity_Id gnat_formal;
2621 Node_Id gnat_actual;
2626 tree gnu_call;
2631 /* If we are calling a stubbed function, raise Program_Error, but Elaborate
2632 all our args first. */
2634 {
2644 {
2647 }
2650 }
2652 /* The only way we can be making a call via an access type is if Name is an
2653 explicit dereference. In that case, get the list of formal args from the
2654 type the access type is pointing to. Otherwise, get the formals from the
2655 entity being called. */
2659 /* Assume here that this must be 'Elab_Body or 'Elab_Spec. */
2661 else
2664 /* If we are translating a statement, open a new nesting level that will
2665 surround it to declare the temporaries created for the call. */
2667 {
2670 }
2672 /* The lifetime of the temporaries created for the call ends with the call
2673 so we can give them the scope of the elaboration routine at top level. */
2675 {
2678 }
2680 /* Create the list of the actual parameters as GCC expects it, namely a
2681 chain of TREE_LIST nodes in which the TREE_VALUE field of each node
2682 is an expression and the TREE_PURPOSE field is null. But skip Out
2683 parameters not passed by reference and that need not be copied in. */
2688 {
2692 /* In the Out or In Out case, we must suppress conversions that yield
2693 an lvalue but can nevertheless cause the creation of a temporary,
2694 because we need the real object in this case, either to pass its
2695 address if it's passed by reference or as target of the back copy
2696 done after the call if it uses the copy-in copy-out mechanism.
2697 We do it in the In case too, except for an unchecked conversion
2698 because it alone can cause the actual to be misaligned and the
2699 addressability test is applied to the real object. */
2700 bool suppress_type_conversion
2705 Node_Id gnat_name = suppress_type_conversion
2708 tree gnu_actual;
2710 /* If it's possible we may need to use this expression twice, make sure
2711 that any side-effects are handled via SAVE_EXPRs; likewise if we need
2712 to force side-effects before the call.
2713 ??? This is more conservative than we need since we don't need to do
2714 this for pass-by-ref with no conversion. */
2718 /* If we are passing a non-addressable parameter by reference, pass the
2719 address of a copy. In the Out or In Out case, set up to copy back
2720 out after the call. */
2728 {
2731 /* Do not issue warnings for CONSTRUCTORs since this is not a copy
2732 but sort of an instantiation for them. */
2734 ;
2736 /* If the type is passed by reference, a copy is not allowed. */
2739 gnat_actual);
2741 /* For users of Starlet we issue a warning because the interface
2742 apparently assumes that by-ref parameters outlive the procedure
2743 invocation. The code still will not work as intended, but we
2744 cannot do much better since low-level parts of the back-end
2745 would allocate temporaries at will because of the misalignment
2746 if we did not do so here. */
2748 {
2749 post_error
2751 post_error_ne
2755 gnat_formal);
2756 }
2758 /* If the actual type of the object is already the nominal type,
2759 we have nothing to do, except if the size is self-referential
2760 in which case we'll remove the unpadding below. */
2763 ;
2765 /* Otherwise remove the unpadding from all the objects. */
2767 && TYPE_IS_PADDING_P
2771 /* Otherwise convert to the nominal type of the object if needed.
2772 There are several cases in which we need to make the temporary
2773 using this type instead of the actual type of the object when
2774 they are distinct, because the expectations of the callee would
2775 otherwise not be met:
2776 - if it's a justified modular type,
2777 - if the actual type is a smaller form of it,
2778 - if it's a smaller form of the actual type. */
2782 gnu_name_type)))
2788 /* Create an explicit temporary holding the copy. This ensures that
2789 its lifetime is as narrow as possible around a statement. */
2796 /* But initialize it on the fly like for an implicit temporary as
2797 we aren't necessarily dealing with a statement. */
2798 gnu_stmt
2802 /* From now on, the real object is the temporary. */
2804 gnu_temp);
2806 /* Set up to move the copy back to the original if needed. */
2808 {
2810 gnu_temp);
2813 }
2814 }
2816 /* Start from the real object and build the actual. */
2819 /* If this was a procedure call, we may not have removed any padding.
2820 So do it here for the part we will use as an input, if any. */
2823 gnu_actual
2826 /* Put back the conversion we suppressed above in the computation of the
2827 real object. And even if we didn't suppress any conversion there, we
2828 may have suppressed a conversion to the Etype of the actual earlier,
2829 since the parent is a procedure call, so put it back here. */
2832 gnu_actual
2835 else
2836 gnu_actual
2839 /* Make sure that the actual is in range of the formal's type. */
2842 gnu_actual
2845 /* Unless this is an In parameter, we must remove any justified modular
2846 building from GNU_NAME to get an lvalue. */
2851 gnu_name
2854 /* If we have not saved a GCC object for the formal, it means it is an
2855 Out parameter not passed by reference and that need not be copied in.
2856 Otherwise, first see if the parameter is passed by reference. */
2860 {
2862 {
2863 /* In Out or Out parameters passed by reference don't use the
2864 copy-in copy-out mechanism so the address of the real object
2865 must be passed to the function. */
2868 /* If we have a padded type, be sure we've removed padding. */
2871 gnu_actual);
2873 /* If we have the constructed subtype of an aliased object
2874 with an unconstrained nominal subtype, the type of the
2875 actual includes the template, although it is formally
2876 constrained. So we need to convert it back to the real
2877 constructed subtype to retrieve the constrained part
2878 and takes its address. */
2884 gnu_actual);
2885 }
2887 /* There is no need to convert the actual to the formal's type before
2888 taking its address. The only exception is for unconstrained array
2889 types because of the way we build fat pointers. */
2893 /* The symmetry of the paths to the type of an entity is broken here
2894 since arguments don't know that they will be passed by ref. */
2897 }
2901 {
2907 {
2910 }
2912 /* Take the address of the object and convert to the proper pointer
2913 type. We'd like to actually compute the address of the beginning
2914 of the array using an ADDR_EXPR of an ARRAY_REF, but there's a
2915 possibility that the ARRAY_REF might return a constant and we'd be
2916 getting the wrong address. Neither approach is exactly correct,
2917 but this is the most likely to work in all cases. */
2919 }
2923 {
2926 /* If this is 'Null_Parameter, pass a zero descriptor. */
2930 gnu_actual
2932 else
2935 gnat_formal,
2936 gnat_actual));
2937 }
2938 else
2939 {
2940 tree gnu_size;
2946 {
2947 /* Make sure side-effects are evaluated before the call. */
2951 }
2955 /* If this is 'Null_Parameter, pass a zero even though we are
2956 dereferencing it. */
2962 gnu_actual
2966 integer_zero_node),
2968 else
2970 }
2973 }
2976 gnu_actual_vec);
2979 /* If it's a function call, the result is the call expression unless a target
2980 is specified, in which case we copy the result into the target and return
2981 the assignment statement. */
2983 {
2986 /* If the function returns an unconstrained array or by direct reference,
2987 we have to dereference the pointer. */
2993 {
2997 /* If range check is needed, emit code to generate it. */
2999 gnu_result
3001 gnat_parent);
3003 /* ??? If the return type has non-constant size, then force the
3004 return slot optimization as we would not be able to generate
3005 a temporary. That's what has been done historically. */
3008 else
3011 gnu_result
3016 }
3017 else
3018 {
3022 }
3025 }
3027 /* If this is the case where the GNAT tree contains a procedure call but the
3028 Ada procedure has copy-in/copy-out parameters, then the special parameter
3029 passing mechanism must be used. */
3031 {
3032 /* List of FIELD_DECLs associated with the PARM_DECLs of the copy-in/
3033 copy-out parameters. */
3038 {
3041 /* The call sequence must contain one and only one call, even though
3042 the function is pure. Save the result into a temporary. */
3049 gnu_stmt
3053 /* Add the call statement to the list and start from its result. */
3058 }
3062 else
3069 /* If we are dealing with a copy in copy out parameter, we must
3070 retrieve its value from the record returned in the call. */
3076 || (DECL_BY_DESCRIPTOR_P
3079 {
3080 /* Get the value to assign to this Out or In Out parameter. It is
3081 either the result of the function if there is only a single such
3082 parameter or the appropriate field from the record returned. */
3083 tree gnu_result
3085 ? gnu_call
3089 /* If the actual is a conversion, get the inner expression, which
3090 will be the real destination, and convert the result to the
3091 type of the actual parameter. */
3092 tree gnu_actual
3095 /* If the result is a padded type, remove the padding. */
3097 gnu_result
3099 gnu_result);
3101 /* If the actual is a type conversion, the real target object is
3102 denoted by the inner Expression and we need to convert the
3103 result to the associated type.
3104 We also need to convert our gnu assignment target to this type
3105 if the corresponding GNU_NAME was constructed from the GNAT
3106 conversion node and not from the inner Expression. */
3108 {
3109 gnu_result
3110 = convert_with_check
3118 }
3120 /* Unchecked conversions as actuals for Out parameters are not
3121 allowed in user code because they are not variables, but do
3122 occur in front-end expansions. The associated GNU_NAME is
3123 always obtained from the inner expression in such cases. */
3126 gnu_result,
3128 else
3129 {
3131 gnu_result
3133 gnat_actual);
3138 }
3146 }
3147 }
3148 else
3156 }
3157 \f
3158 /* Subroutine of gnat_to_gnu to translate gnat_node, an
3159 N_Handled_Sequence_Of_Statements, to a GCC tree, which is returned. */
3161 static tree
3163 {
3166 /* If just annotating, ignore all EH and cleanups. */
3170 bool setjmp_longjmp
3176 tree gnu_result;
3177 tree gnu_expr;
3178 Node_Id gnat_temp;
3180 /* The GCC exception handling mechanism can handle both ZCX and SJLJ schemes
3181 and we have our own SJLJ mechanism. To call the GCC mechanism, we call
3182 add_cleanup, and when we leave the binding, end_stmt_group will create
3183 the TRY_FINALLY_EXPR.
3185 ??? The region level calls down there have been specifically put in place
3186 for a ZCX context and currently the order in which things are emitted
3187 (region/handlers) is different from the SJLJ case. Instead of putting
3188 other calls with different conditions at other places for the SJLJ case,
3189 it seems cleaner to reorder things for the SJLJ case and generalize the
3190 condition to make it not ZCX specific.
3192 If there are any exceptions or cleanup processing involved, we need an
3193 outer statement group (for Setjmp_Longjmp) and binding level. */
3195 {
3198 }
3200 /* If using setjmp_longjmp, make the variables for the setjmp buffer and save
3201 area for address of previous buffer. Do this first since we need to have
3202 the setjmp buf known for any decls in this block. */
3204 {
3209 gnat_node);
3212 /* The __builtin_setjmp receivers will immediately reinstall it. Now
3213 because of the unstructured form of EH used by setjmp_longjmp, there
3214 might be forward edges going to __builtin_setjmp receivers on which
3215 it is uninitialized, although they will never be actually taken. */
3225 /* When we exit this block, restore the saved value. */
3228 }
3230 /* If we are to call a function when exiting this block, add a cleanup
3231 to the binding level we made above. Note that add_cleanup is FIFO
3232 so we must register this cleanup after the EH cleanup just above. */
3237 /* Now build the tree for the declarations and statements inside this block.
3238 If this is SJLJ, set our jmp_buf as the current buffer. */
3244 gnu_jmpbuf_decl)));
3250 /* Generate code for each statement in the block. */
3258 /* Now generate code for the two exception models, if either is relevant for
3259 this block. */
3261 {
3263 tree gnu_handler;
3265 /* Make a binding level for the exception handling declarations and code
3266 and set up gnu_except_ptr_stack for the handlers to use. */
3272 NULL_TREE,
3278 /* Generate code for each handler. The N_Exception_Handler case does the
3279 real work and returns a COND_EXPR for each handler, which we chain
3280 together here. */
3283 {
3286 /* If this is the first one, set it as the outer one. Otherwise,
3287 point the "else" part of the previous handler to us. Then point
3288 to our "else" part. */
3291 else
3295 }
3297 /* If none of the exception handlers did anything, re-raise but do not
3298 defer abortion. */
3301 set_expr_location_from_node
3307 else
3310 /* End the binding level dedicated to the exception handlers and get the
3311 whole statement group. */
3316 /* If the setjmp returns 1, we restore our incoming longjmp value and
3317 then check the handlers. */
3320 gnu_jmpsave_decl),
3321 gnat_node);
3325 /* This block is now "if (setjmp) ... <handlers> else <block>". */
3327 (build_call_1_expr
3330 gnu_jmpbuf_decl))),
3332 }
3334 {
3335 tree gnu_handlers;
3337 /* First make a block containing the handlers. */
3345 /* Now make the TRY_CATCH_EXPR for the block. */
3348 }
3349 else
3352 /* Now close our outer block, if we had to make one. */
3354 {
3358 }
3361 }
3362 \f
3363 /* Subroutine of gnat_to_gnu to translate gnat_node, an N_Exception_Handler,
3364 to a GCC tree, which is returned. This is the variant for Setjmp_Longjmp
3365 exception handling. */
3367 static tree
3369 {
3370 /* Unless this is "Others" or the special "Non-Ada" exception for Ada, make
3371 an "if" statement to select the proper exceptions. For "Others", exclude
3372 exceptions where Handled_By_Others is nonzero unless the All_Others flag
3373 is set. For "Non-ada", accept an exception if "Lang" is 'V'. */
3376 Node_Id gnat_temp;
3380 {
3381 tree this_choice;
3384 {
3387 else
3388 this_choice
3389 = build_binary_op
3391 convert
3393 build_component_ref
3394 (build_unary_op
3399 integer_zero_node);
3400 }
3404 {
3406 tree gnu_expr;
3408 /* Exception may be a renaming. Recover original exception which is
3409 the one elaborated and registered. */
3415 this_choice
3416 = build_binary_op
3422 /* If this is the distinguished exception "Non_Ada_Error" (and we are
3423 in VMS mode), also allow a non-Ada exception (a VMS condition) t
3424 match. */
3426 {
3427 tree gnu_comp
3428 = build_component_ref
3433 this_choice
3434 = build_binary_op
3438 this_choice);
3439 }
3440 }
3441 else
3446 }
3449 }
3450 \f
3451 /* Subroutine of gnat_to_gnu to translate gnat_node, an N_Exception_Handler,
3452 to a GCC tree, which is returned. This is the variant for ZCX. */
3454 static tree
3456 {
3458 tree gnu_expr;
3459 tree gnu_etype;
3460 tree gnu_current_exc_ptr;
3461 tree gnu_incoming_exc_ptr;
3462 Node_Id gnat_temp;
3464 /* We build a TREE_LIST of nodes representing what exception types this
3465 handler can catch, with special cases for others and all others cases.
3467 Each exception type is actually identified by a pointer to the exception
3468 id, or to a dummy object for "others" and "all others". */
3471 {
3473 {
3474 tree gnu_expr
3477 gnu_etype
3479 }
3482 {
3485 /* Exception may be a renaming. Recover original exception which is
3486 the one elaborated and registered. */
3493 /* The Non_Ada_Error case for VMS exceptions is handled
3494 by the personality routine. */
3495 }
3496 else
3499 /* The GCC interface expects NULL to be passed for catch all handlers, so
3500 it would be quite tempting to set gnu_etypes_list to NULL if gnu_etype
3501 is integer_zero_node. It would not work, however, because GCC's
3502 notion of "catch all" is stronger than our notion of "others". Until
3503 we correctly use the cleanup interface as well, doing that would
3504 prevent the "all others" handlers from being seen, because nothing
3505 can be caught beyond a catch all from GCC's point of view. */
3507 }
3512 /* Expand a call to the begin_handler hook at the beginning of the handler,
3513 and arrange for a call to the end_handler hook to occur on every possible
3514 exit path.
3516 The hooks expect a pointer to the low level occurrence. This is required
3517 for our stack management scheme because a raise inside the handler pushes
3518 a new occurrence on top of the stack, which means that this top does not
3519 necessarily match the occurrence this handler was dealing with.
3521 __builtin_eh_pointer references the exception occurrence being
3522 propagated. Upon handler entry, this is the exception for which the
3523 handler is triggered. This might not be the case upon handler exit,
3524 however, as we might have a new occurrence propagated by the handler's
3525 body, and the end_handler hook called as a cleanup in this context.
3527 We use a local variable to retrieve the incoming value at handler entry
3528 time, and reuse it to feed the end_handler hook's argument at exit. */
3530 gnu_current_exc_ptr
3536 gnat_node);
3539 gnu_incoming_exc_ptr),
3540 gnat_node);
3541 /* ??? We don't seem to have an End_Label at hand to set the location. */
3543 Empty);
3549 }
3550 \f
3551 /* Subroutine of gnat_to_gnu to generate code for an N_Compilation unit. */
3553 static void
3555 {
3560 /* Make the decl for the elaboration procedure. */
3561 tree gnu_elab_proc_decl
3562 = create_subprog_decl
3570 /* Initialize the information structure for the function. */
3579 /* For a body, first process the spec if there is one. */
3583 {
3586 }
3588 /* If we can inline, generate code for all the inlined subprograms. */
3590 {
3591 Entity_Id gnat_entity;
3596 {
3600 {
3601 /* ??? This really should always be present. */
3604 gnat_body
3606 }
3609 {
3610 /* Define the entity first so we set DECL_EXTERNAL. */
3613 }
3614 }
3615 }
3618 {
3625 }
3631 /* Process any pragmas and actions following the unit. */
3636 /* Save away what we've made so far and record this potential elaboration
3637 procedure. */
3643 Sloc_to_locus
3652 /* Generate elaboration code for this unit, if necessary, and say whether
3653 we did or not. */
3656 /* Invalidate the global renaming pointers. This is necessary because
3657 stabilization of the renamed entities may create SAVE_EXPRs which
3658 have been tied to a specific elaboration routine just above. */
3660 }
3661 \f
3662 /* Return true if GNAT_NODE, an unchecked type conversion, is a no-op as far
3663 as gigi is concerned. This is used to avoid conversions on the LHS. */
3665 static bool
3667 {
3670 /* The conversion must be on the LHS of an assignment or an actual parameter
3671 of a call. Otherwise, even if the conversion was essentially a no-op, it
3672 could de facto ensure type consistency and this should be preserved. */
3682 /* We're interested in artificial conversions generated by the front-end
3683 to make private types explicit, e.g. in Expand_Assign_Array. */
3690 /* The direct conversion to the underlying type is a no-op. */
3694 /* For an array subtype, the conversion to the PAT is a no-op. */
3699 /* For a record subtype, the conversion to the type is a no-op. */
3705 }
3707 /* This function is the driver of the GNAT to GCC tree transformation process.
3708 It is the entry point of the tree transformer. GNAT_NODE is the root of
3709 some GNAT tree. Return the root of the corresponding GCC tree. If this
3710 is an expression, return the GCC equivalent of the expression. If this
3711 is a statement, return the statement or add it to the current statement
3712 group, in which case anything returned is to be interpreted as occurring
3713 after anything added. */
3715 tree
3717 {
3723 Node_Id gnat_temp;
3725 /* Save node number for error message and set location information. */
3729 /* If this node is a statement and we are only annotating types, return an
3730 empty statement list. */
3734 /* If this node is a non-static subexpression and we are only annotating
3735 types, make this into a NULL_EXPR. */
3742 N_Raise_Constraint_Error));
3751 {
3752 /* If this is a statement and we are at top level, it must be part of
3753 the elaboration procedure, so mark us as being in that procedure. */
3755 {
3758 }
3760 /* If we are in the elaboration procedure, check if we are violating a
3761 No_Elaboration_Code restriction by having a statement there. Don't
3762 check for a possible No_Elaboration_Code restriction violation on
3763 N_Handled_Sequence_Of_Statements, as we want to signal an error on
3764 every nested real statement instead. This also avoids triggering
3765 spurious errors on dummy (empty) sequences created by the front-end
3766 for package bodies in some cases. */
3770 }
3773 {
3774 /********************************/
3775 /* Chapter 2: Lexical Elements */
3776 /********************************/
3786 {
3787 tree gnu_type;
3789 /* Get the type of the result, looking inside any padding and
3790 justified modular types. Then get the value in that type. */
3799 /* If the result overflows (meaning it doesn't fit in its base type),
3800 abort. We would like to check that the value is within the range
3801 of the subtype, but that causes problems with subtypes whose usage
3802 will raise Constraint_Error and with biased representation, so
3803 we don't. */
3805 }
3809 /* If a Entity is present, it means that this was one of the
3810 literals in a user-defined character type. In that case,
3811 just return the value in the CONST_DECL. Otherwise, use the
3812 character code. In that case, the base type should be an
3813 INTEGER_TYPE, but we won't bother checking for that. */
3817 else
3818 gnu_result
3819 = build_int_cst_type
3824 /* If this is of a fixed-point type, the value we want is the
3825 value of the corresponding integer. */
3827 {
3830 gnu_result_type);
3832 }
3834 /* We should never see a Vax_Float type literal, since the front end
3835 is supposed to transform these using appropriate conversions. */
3839 else
3840 {
3845 /* If the real value is zero, so is the result. Otherwise,
3846 convert it to a machine number if it isn't already. That
3847 forces BASE to 0 or 2 and simplifies the rest of our logic. */
3850 else
3851 {
3853 ur_realval
3857 gnu_result
3860 /* If we have a base of zero, divide by the denominator.
3861 Otherwise, the base must be 2 and we scale the value, which
3862 we know can fit in the mantissa of the type (hence the use
3863 of that type above). */
3865 gnu_result
3868 gnu_result,
3870 gnu_result_type));
3871 else
3872 {
3873 REAL_VALUE_TYPE tmp;
3879 }
3880 }
3882 /* Now see if we need to negate the result. Do it this way to
3883 properly handle -0. */
3885 gnu_result
3887 gnu_result);
3888 }
3895 {
3902 else
3905 /* Build the string with the characters in the literal. Note
3906 that Ada strings are 1-origin. */
3910 /* Put a null at the end of the string in case it's in a context
3911 where GCC will want to treat it as a C string. */
3916 /* Strings in GCC don't normally have types, but we want
3917 this to not be converted to the array type. */
3922 }
3923 else
3924 {
3925 /* Build a list consisting of each character, then make
3926 the aggregate. */
3935 {
3942 }
3945 }
3952 /**************************************/
3953 /* Chapter 3: Declarations and Types */
3954 /**************************************/
3971 /* If we are just annotating types and this object has an unconstrained
3972 or task type, don't elaborate it. */
3982 && (!type_annotate_only
3984 {
3987 gnu_expr
3990 /* If this object has its elaboration delayed, we must force
3991 evaluation of GNU_EXPR right now and save it for when the object
3992 is frozen. */
3994 {
3997 gnu_expr
4002 else
4006 }
4007 }
4008 else
4014 /* If this is a deferred constant with an address clause, we ignore the
4015 full view since the clause is on the partial view and we cannot have
4016 2 different GCC trees for the object. The only bits of the full view
4017 we will use is the initializer, but it will be directly fetched. */
4030 /* Don't do anything if this renaming is handled by the front end or if
4031 we are just annotating types and this object has a composite or task
4032 type, don't elaborate it. We return the result in case it has any
4033 SAVE_EXPRs in it that need to be evaluated here. */
4035 && ! (type_annotate_only
4039 gnu_result
4042 else
4055 /* These are fully handled in the front end. */
4059 /*************************************/
4060 /* Chapter 4: Names and Expressions */
4061 /*************************************/
4070 {
4072 tree gnu_type;
4079 /* Convert vector inputs to their representative array type, to fit
4080 what the code below expects. */
4085 /* If we got a padded type, remove it too. */
4087 gnu_array_object
4089 gnu_array_object);
4093 /* First compute the number of dimensions of the array, then
4094 fill the expression array, the order depending on whether
4095 this is a Convention_Fortran array or not. */
4100 ;
4109 else
4117 {
4123 gnu_expr
4124 = emit_index_check
4128 gnat_temp);
4132 }
4133 }
4139 {
4141 tree gnu_type;
4146 /* Do any implicit dereferences of the prefix and do any needed
4147 range check. */
4152 {
4153 /* Get the bounds of the slice. */
4154 tree gnu_index_type
4158 /* Get the permitted bounds. */
4159 tree gnu_base_index_type
4161 tree gnu_base_min_expr = SUBSTITUTE_PLACEHOLDER_IN_EXPR
4163 tree gnu_base_max_expr = SUBSTITUTE_PLACEHOLDER_IN_EXPR
4170 /* Derive a good type to convert everything to. */
4173 /* Test whether the minimum slice value is too small. */
4176 gnu_min_expr),
4178 gnu_base_min_expr));
4180 /* Test whether the maximum slice value is too large. */
4183 gnu_max_expr),
4185 gnu_base_max_expr));
4187 /* Build a slice index check that returns the low bound,
4188 assuming the slice is not empty. */
4189 gnu_expr = emit_check
4194 /* Build a conditional expression that does the index checks and
4195 returns the low bound if the slice is not empty (max >= min),
4196 and returns the naked low bound otherwise (max < min), unless
4197 it is non-constant and the high bound is; this prevents VRP
4198 from inferring bogus ranges on the unlikely path. */
4202 gnu_max_expr),
4204 gnu_min_expr)),
4205 gnu_expr,
4209 }
4210 else
4211 /* Simply return the naked low bound. */
4214 /* If this is a slice with non-constant size of an array with constant
4215 size, set the maximum size for the allocation of temporaries. */
4222 }
4226 {
4230 tree gnu_field;
4234 {
4239 }
4243 /* For discriminant references in tagged types always substitute the
4244 corresponding discriminant as the actual selected component. */
4249 /* For discriminant references of untagged types always substitute the
4250 corresponding stored discriminant. */
4254 /* Handle extracting the real or imaginary part of a complex.
4255 The real part is the first field and the imaginary the last. */
4260 else
4261 {
4264 /* If there are discriminants, the prefix might be evaluated more
4265 than once, which is a problem if it has side-effects. */
4272 gnu_result
4276 && lvalue_required_for_attribute_p
4278 }
4282 }
4286 {
4287 /* The attribute designator. */
4290 /* The Elab_Spec and Elab_Body attributes are special in that Prefix
4291 is a unit, not an object with a GCC equivalent. */
4293 return
4301 }
4305 /* Like 'Access as far as we are concerned. */
4313 {
4314 tree gnu_aggr_type;
4316 /* ??? It is wrong to evaluate the type now, but there doesn't
4317 seem to be any other practical way of doing it. */
4321 gnu_aggr_type = gnu_result_type
4326 gnu_aggr_type
4336 gnu_result
4339 gnu_aggr_type);
4342 gnu_aggr_type,
4345 gnu_result
4346 = build_binary_op
4351 (Next
4353 else
4357 }
4365 else
4372 /* Get the operand expression. */
4376 gnu_result
4380 kind == N_Type_Conversion
4387 /* Skip further processing if the conversion is deemed a no-op. */
4389 {
4392 }
4396 /* If the result is a pointer type, see if we are improperly
4397 converting to a stricter alignment. */
4400 {
4406 post_error_ne_tree_2
4410 }
4412 /* If we are converting a descriptor to a function pointer, first
4413 build the pointer. */
4425 {
4430 /* GNAT_RANGE is either an N_Range node or an identifier denoting a
4431 subtype. */
4433 {
4436 }
4439 {
4444 }
4445 else
4450 /* If LOW and HIGH are identical, perform an equality test. Otherwise,
4451 ensure that GNU_OBJ is evaluated only once and perform a full range
4452 test. */
4454 gnu_result
4456 else
4457 {
4466 gnu_result
4468 }
4472 }
4480 ? RDIV_EXPR
4487 /* These can either be operations on booleans or on modular types.
4488 Fall through for boolean types since that's the way GNU_CODES is
4489 set up. */
4491 Modular_Integer_Kind))
4492 {
4493 enum tree_code code
4504 }
4506 /* ... fall through ... */
4518 {
4522 tree gnu_type;
4528 /* Pending generic support for efficient vector logical operations in
4529 GCC, convert vectors to their representative array type view and
4530 fallthrough. */
4534 /* If this is a comparison operator, convert any references to
4535 an unconstrained array value into a reference to the
4536 actual array. */
4538 {
4541 }
4543 /* If the result type is a private type, its full view may be a
4544 numeric subtype. The representation we need is that of its base
4545 type, given that it is the result of an arithmetic operation. */
4547 gnu_type = gnu_result_type
4550 /* If this is a shift whose count is not guaranteed to be correct,
4551 we need to adjust the shift count. */
4553 {
4555 tree gnu_max_shift
4562 gnu_rhs
4563 = build_binary_op
4566 gnu_count_type,
4567 gnu_max_shift,
4569 integer_one_node)),
4570 gnu_rhs);
4571 }
4573 /* For right shifts, the type says what kind of shift to do,
4574 so we may need to choose a different type. In this case,
4575 we have to ignore integer overflow lest it propagates all
4576 the way down and causes a CE to be explicitly raised. */
4578 {
4581 }
4584 {
4587 }
4590 {
4596 }
4598 /* Instead of expanding overflow checks for addition, subtraction
4599 and multiplication itself, the front end will leave this to
4600 the back end when Backend_Overflow_Checks_On_Target is set.
4601 As the GCC back end itself does not know yet how to properly
4602 do overflow checking, do it here. The goal is to push
4603 the expansions further into the back end over time. */
4612 else
4613 {
4614 /* Some operations, e.g. comparisons of arrays, generate complex
4615 trees that need to be annotated while they are being built. */
4618 }
4620 /* If this is a logical shift with the shift count not verified,
4621 we must return zero if it is too large. We cannot compensate
4622 above in this case. */
4625 gnu_result
4626 = build_cond_expr
4629 gnu_rhs,
4633 gnu_result);
4634 }
4638 {
4641 tree gnu_false
4645 gnu_result
4647 }
4656 /* This case can apply to a boolean or a modular type.
4657 Fall through for a boolean operand since GNU_CODES is set
4658 up to handle this. */
4662 {
4666 gnu_expr);
4668 }
4670 /* ... fall through ... */
4677 else
4684 gnu_result
4687 else
4693 {
4695 tree gnu_type;
4700 /* The Expression operand can either be an N_Identifier or
4701 Expanded_Name, which must represent a type, or a
4702 N_Qualified_Expression, which contains both the object type and an
4703 initial value for the object. */
4708 {
4709 Entity_Id gnat_desig_type
4717 gnu_init
4722 {
4725 }
4726 else
4727 {
4733 }
4734 }
4735 else
4742 ignore_init_type);
4743 }
4746 /**************************/
4747 /* Chapter 5: Statements */
4748 /**************************/
4756 /* When not optimizing, turn null statements from source into gotos to
4757 the next statement that the middle-end knows how to preserve. */
4759 {
4769 }
4770 else
4775 /* Get the LHS and RHS of the statement and convert any reference to an
4776 unconstrained array into a reference to the underlying array. */
4779 /* If the type has a size that overflows, convert this into raise of
4780 Storage_Error: execution shouldn't have gotten here anyway. */
4784 N_Raise_Storage_Error);
4786 gnu_result
4788 else
4789 {
4790 gnu_rhs
4793 /* If range check is needed, emit code to generate it. */
4796 gnat_node);
4798 gnu_result
4801 /* If the type being assigned is an array type and the two sides are
4802 not completely disjoint, play safe and use memmove. But don't do
4803 it for a bit-packed array as it might not be byte-aligned. */
4808 {
4822 }
4823 }
4827 {
4830 /* Make the outer COND_EXPR. Avoid non-determinism. */
4839 /* Now make a COND_EXPR for each of the "else if" parts. Put each
4840 into the previous "else" part and point to where to put any
4841 outer "else". Also avoid non-determinism. */
4845 {
4855 }
4858 }
4882 gnu_result
4892 {
4895 /* If we have a return label defined, convert this into a branch to
4896 that label. The return proper will be handled elsewhere. */
4898 {
4901 /* When not optimizing, make sure the return is preserved. */
4905 }
4907 /* If the subprogram is a function, we must return the expression. */
4909 {
4914 /* Do not remove the padding from GNU_RET_VAL if the inner type is
4915 self-referential since we want to allocate the fixed size. */
4917 && TYPE_IS_PADDING_P
4919 && CONTAINS_PLACEHOLDER_P
4923 /* If the subprogram returns by direct reference, return a pointer
4924 to the return value. */
4929 /* Otherwise, if it returns an unconstrained array, we have to
4930 allocate a new version of the result and return it. */
4932 {
4935 gnu_ret_val,
4940 }
4942 /* If the subprogram returns by invisible reference, dereference
4943 the pointer it is passed using the type of the return value
4944 and build the copy operation manually. This ensures that we
4945 don't copy too much data, for example if the return type is
4946 unconstrained with a maximum size. */
4948 {
4949 gnu_ret_obj
4951 gnu_result_decl);
4957 }
4959 /* Otherwise, build a regular return. */
4960 else
4962 }
4963 else
4964 {
4967 }
4970 }
4978 /***************************/
4979 /* Chapter 6: Subprograms */
4980 /***************************/
4983 /* Unless there is a freeze node, declare the subprogram. We consider
4984 this a "definition" even though we're not generating code for
4985 the subprogram because we will be making the corresponding GCC
4986 node here. */
4995 /* This subprogram doesn't exist for code generation purposes, but we
4996 have to elaborate the types of any parameters and result, unless
4997 they are imported types (nothing to generate in this case). */
4999 /* Process the parameter types first. */
5002 = First_Formal_With_Extras
5011 /* Then the result type, set to Standard_Void_Type for procedures. */
5013 {
5014 Entity_Id gnat_temp_type
5019 }
5025 /* For a child unit identifier go up a level to get the specification.
5026 We get this when we try to find the spec of a child unit package
5027 that is the compilation unit being compiled. */
5041 /************************/
5042 /* Chapter 7: Packages */
5043 /************************/
5059 /* If this is the body of a generic package - do nothing. */
5061 {
5064 }
5075 /********************************/
5076 /* Chapter 8: Visibility Rules */
5077 /********************************/
5081 /* Nothing to do here - but these may appear in list of declarations. */
5085 /*********************/
5086 /* Chapter 9: Tasks */
5087 /*********************/
5098 /*********************************************************/
5099 /* Chapter 10: Program Structure and Compilation Issues */
5100 /*********************************************************/
5103 /* This is not called for the main unit on which gigi is invoked. */
5112 /* Simply process whatever unit is being inserted. */
5120 /***************************/
5121 /* Chapter 11: Exceptions */
5122 /***************************/
5125 /* If there is an At_End procedure attached to this node, and the EH
5126 mechanism is SJLJ, we must have at least a corresponding At_End
5127 handler, unless the No_Exception_Handlers restriction is set. */
5142 else
5174 /******************************/
5175 /* Chapter 12: Generic Units */
5176 /******************************/
5186 /* These nodes can appear on a declaration list but there is nothing to
5187 to be done with them. */
5191 /**************************************************/
5192 /* Chapter 13: Representation Clauses and */
5193 /* Implementation-Dependent Features */
5194 /**************************************************/
5199 /* The only one we need to deal with is 'Address since, for the others,
5200 the front-end puts the information elsewhere. */
5204 /* And we only deal with 'Address if the object has a Freeze node. */
5209 /* Get the value to use as the address and save it as the equivalent
5210 for the object. When it is frozen, gnat_to_gnu_entity will do the
5211 right thing. */
5218 /* We do nothing with these. SEM puts the information elsewhere. */
5224 {
5234 /* First retrieve the 3 operand lists built by the front-end. */
5237 {
5244 }
5248 {
5255 }
5259 gnu_clobbers
5262 gnu_clobbers);
5264 /* Then perform some standard checking and processing on the
5265 operands. In particular, mark them addressable if needed. */
5270 oconstraints
5274 {
5276 constraint
5282 {
5283 /* If the operand is going to end up in memory,
5284 mark it addressable. Note that we don't test
5285 allows_mem like in the input case below; this
5286 is modelled on the C front-end. */
5290 }
5291 else
5295 }
5298 {
5300 constraint
5306 {
5307 /* If the operand is going to end up in memory,
5308 mark it addressable. */
5312 }
5313 else
5317 }
5323 }
5324 else
5329 /****************/
5330 /* Added Nodes */
5331 /****************/
5335 /* This construct doesn't define a scope so we don't wrap the statement
5336 list in a BIND_EXPR; however, we wrap it in a SAVE_EXPR to protect it
5337 from unsharing. */
5342 gnu_result
5362 {
5365 tree gnu_obj_type;
5367 tree gnu_obj_size;
5369 /* If this is a thin pointer, we must dereference it to create
5370 a fat pointer, then go back below to a thin pointer. The
5371 reason for this is that we need a fat pointer someplace in
5372 order to properly compute the size. */
5376 gnu_ptr));
5378 /* If this is an unconstrained array, we know the object must
5379 have been allocated with the template in front of the object.
5380 So pass the template address, but get the total size. Do this
5381 by converting to a thin pointer. */
5383 gnu_ptr
5385 (TYPE_OBJECT_RECORD_TYPE
5387 gnu_ptr);
5392 {
5393 gnu_actual_obj_type
5397 gnu_actual_obj_type
5399 gnu_actual_obj_type,
5402 }
5403 else
5410 {
5411 tree gnu_char_ptr_type
5417 }
5419 gnu_result
5423 gnat_node);
5424 }
5431 {
5434 }
5437 gnu_result
5440 /* If the type is VOID, this is a statement, so we need to
5441 generate the code for the call. Handle a Condition, if there
5442 is one. */
5444 {
5451 }
5452 else
5457 {
5462 /* No need for any warning in this case. */
5464 ;
5466 /* If the result is a pointer type, see if we are either converting
5467 from a non-pointer or from a pointer to a type with a different
5468 alias set and warn if so. If the result is defined in the same
5469 unit as this unchecked conversion, we can allow this because we
5470 can know to make the pointer type behave properly. */
5474 {
5487 || !alias_sets_conflict_p
5490 {
5491 post_error_ne
5494 post_error
5496 gnat_node);
5497 post_error_ne
5500 }
5501 }
5503 /* But if the result is a fat pointer type, we have no mechanism to
5504 do that, so we unconditionally warn in problematic cases. */
5506 {
5507 tree gnu_source_array_type
5511 tree gnu_target_array_type
5521 || !alias_sets_conflict_p
5524 {
5525 post_error_ne
5528 post_error
5530 gnat_node);
5531 }
5532 }
5533 }
5538 /* SCIL nodes require no processing for GCC. Other nodes should only
5539 be present when annotating types. */
5542 }
5544 /* If we pushed the processing of the elaboration routine, pop it back. */
5548 /* When not optimizing, turn boolean rvalues B into B != false tests
5549 so that the code just below can put the location information of the
5550 reference to B on the inequality operator for better debug info. */
5563 boolean_false_node));
5565 /* Set the location information on the result. Note that we may have
5566 no result if we tried to build a CALL_EXPR node to a procedure with
5567 no side-effects and optimization is enabled. */
5571 /* If we're supposed to return something of void_type, it means we have
5572 something we're elaborating for effect, so just return. */
5576 /* If the result is a constant that overflowed, raise Constraint_Error. */
5578 {
5580 gnu_result
5583 N_Raise_Constraint_Error));
5584 }
5586 /* If our result has side-effects and is of an unconstrained type,
5587 make a SAVE_EXPR so that we can be sure it will only be referenced
5588 once. Note we must do this before any conversions. */
5594 /* Now convert the result to the result type, unless we are in one of the
5595 following cases:
5597 1. If this is the Name of an assignment statement or a parameter of
5598 a procedure call, return the result almost unmodified since the
5599 RHS will have to be converted to our type in that case, unless
5600 the result type has a simpler size. Likewise if there is just
5601 a no-op unchecked conversion in-between. Similarly, don't convert
5602 integral types that are the operands of an unchecked conversion
5603 since we need to ignore those conversions (for 'Valid).
5605 2. If we have a label (which doesn't have any well-defined type), a
5606 field or an error, return the result almost unmodified. Also don't
5607 do the conversion if the result type involves a PLACEHOLDER_EXPR in
5608 its size since those are the cases where the front end may have the
5609 type wrong due to "instantiating" the unconstrained record with
5610 discriminant values. Similarly, if the two types are record types
5611 with the same name don't convert. This will be the case when we are
5612 converting from a packable version of a type to its original type and
5613 we need those conversions to be NOPs in order for assignments into
5614 these types to work properly.
5616 3. If the type is void or if we have no result, return error_mark_node
5617 to show we have no result.
5619 4. Finally, if the type of the result is already correct. */
5641 && (CONTAINS_PLACEHOLDER_P
5645 {
5646 /* Remove padding only if the inner object is of self-referential
5647 size: in that case it must be an object of unconstrained type
5648 with a default discriminant and we want to avoid copying too
5649 much data. */
5654 gnu_result);
5655 }
5668 {
5669 /* Remove any padding. */
5672 gnu_result);
5673 }
5681 /* We don't need any NOP_EXPR or NON_LVALUE_EXPR on the result. */
5688 }
5689 \f
5690 /* Subroutine of above to push the exception label stack. GNU_STACK is
5691 a pointer to the stack to update and GNAT_LABEL, if present, is the
5692 label to push onto the stack. */
5694 static void
5696 {
5702 }
5703 \f
5704 /* Record the current code position in GNAT_NODE. */
5706 static void
5708 {
5713 }
5715 /* Insert the code for GNAT_NODE at the position saved for that node. */
5717 static void
5719 {
5722 }
5723 \f
5724 /* Start a new statement group chained to the previous group. */
5726 void
5728 {
5731 /* First see if we can get one from the free list. */
5734 else
5740 }
5742 /* Add GNU_STMT to the current statement group. */
5744 void
5746 {
5748 }
5750 /* Similar, but set the location of GNU_STMT to that of GNAT_NODE. */
5752 void
5754 {
5758 }
5760 /* Add a declaration statement for GNU_DECL to the current statement group.
5761 Get SLOC from Entity_Id. */
5763 void
5765 {
5769 /* If this is a variable that Gigi is to ignore, we may have been given
5770 an ERROR_MARK. So test for it. We also might have been given a
5771 reference for a renaming. So only do something for a decl. Also
5772 ignore a TYPE_DECL for an UNCONSTRAINED_ARRAY_TYPE. */
5780 /* If we are global, we don't want to actually output the DECL_EXPR for
5781 this decl since we already have evaluated the expressions in the
5782 sizes and positions as globals and doing it again would be wrong. */
5784 {
5785 /* Mark everything as used to prevent node sharing with subprograms.
5786 Note that walk_tree knows how to deal with TYPE_DECL, but neither
5787 VAR_DECL nor CONST_DECL. This appears to be somewhat arbitrary. */
5791 {
5795 }
5796 /* In any case, we have to deal with our own TYPE_ADA_SIZE field. */
5803 }
5804 else
5807 /* If this is a variable and an initializer is attached to it, it must be
5808 valid for the context. Similar to init_const in create_var_decl_1. */
5815 {
5816 /* If GNU_DECL has a padded type, convert it to the unpadded
5817 type so the assignment is done properly. */
5820 else
5827 {
5830 }
5833 }
5834 }
5836 /* Callback for walk_tree to mark the visited trees rooted at *TP. */
5838 static tree
5840 {
5846 /* Don't mark a dummy type as visited because we want to mark its sizes
5847 and fields once it's filled in. */
5855 }
5857 /* Mark nodes rooted at T with TREE_VISITED and types as having their
5858 sized gimplified. We use this to indicate all variable sizes and
5859 positions in global types may not be shared by any subprogram. */
5861 void
5863 {
5865 }
5867 /* Add GNU_CLEANUP, a cleanup action, to the current code group and
5868 set its location to that of GNAT_NODE if present. */
5870 static void
5872 {
5876 }
5878 /* Set the BLOCK node corresponding to the current code group to GNU_BLOCK. */
5880 void
5882 {
5885 }
5887 /* Return code corresponding to the current code group. It is normally
5888 a STATEMENT_LIST, but may also be a BIND_EXPR or TRY_FINALLY_EXPR if
5889 BLOCK or cleanups were set. */
5891 tree
5893 {
5897 /* If this is a null list, allocate a new STATEMENT_LIST. Then, if there
5898 are cleanups, make a TRY_FINALLY_EXPR. Last, if there is a BLOCK,
5899 make a BIND_EXPR. Note that we nest in that because the cleanup may
5900 reference variables in the block. */
5912 /* Remove this group from the stack and add it to the free list. */
5918 }
5920 /* Add a list of statements from GNAT_LIST, a possibly-empty list of
5921 statements.*/
5923 static void
5925 {
5926 Node_Id gnat_node;
5932 }
5934 /* Build a tree from GNAT_LIST, a possibly-empty list of statements.
5935 If BINDING_P is true, push and pop a binding level around the list. */
5937 static tree
5939 {
5949 }
5950 \f
5951 /* Generate GIMPLE in place for the expression at *EXPR_P. */
5953 int
5956 {
5958 tree op;
5964 {
5966 /* If this is for a scalar, just make a VAR_DECL for it. If for
5967 an aggregate, get a null pointer of the appropriate type and
5968 dereference it. */
5972 integer_zero_node));
5973 else
5974 {
5977 }
5983 /* We should only do this if we are just elaborating for side-effects,
5984 but we can't know that yet. */
5992 {
5993 /* If we are taking the address of a constant CONSTRUCTOR, make sure
5994 it is put into static memory. We know it's going to be read-only
5995 given the semantics we have and it must be in static memory when
5996 the reference is in an elaboration procedure. */
5998 {
6001 }
6003 /* Otherwise explicitly create the local temporary. That's required
6004 if the type is passed by reference. */
6005 else
6006 {
6016 }
6019 }
6026 /* The expressions for the RM bounds must be gimplified to ensure that
6027 they are properly elaborated. See gimplify_decl_expr. */
6031 {
6036 {
6041 {
6045 }
6049 {
6053 }
6055 }
6060 }
6062 /* ... fall through ... */
6066 }
6067 }
6069 /* Generate GIMPLE in place for the statement at *STMT_P. */
6071 static enum gimplify_status
6073 {
6077 {
6083 {
6088 tree t;
6090 /* Build the condition expression from the test, if any. */
6092 gnu_cond
6096 /* Set to emit the statements of the loop. */
6099 /* We first emit the start label and then a conditional jump to the
6100 end label if there's a top condition, then the update if it's at
6101 the top, then the body of the loop, then a conditional jump to
6102 the end label if there's a bottom condition, then the update if
6103 it's at the bottom, and finally a jump to the start label and the
6104 definition of the end label. */
6106 gnu_start_label),
6107 stmt_p);
6128 gnu_end_label),
6129 stmt_p);
6131 }
6134 /* Build a statement to jump to the corresponding end label, then
6135 see if it needs to be conditional. */
6144 }
6145 }
6146 \f
6147 /* Force references to each of the entities in packages withed by GNAT_NODE.
6148 Operate recursively but check that we aren't elaborating something more
6149 than once.
6151 This routine is exclusively called in type_annotate mode, to compute DDA
6152 information for types in withed units, for ASIS use. */
6154 static void
6156 {
6159 /* Process each unit only once. As we trace the context of all relevant
6160 units transitively, including generic bodies, we may encounter the
6161 same generic unit repeatedly. */
6165 /* Save entities in all context units. A body may have an implicit_with
6166 on its own spec, if the context includes a child unit, so don't save
6167 the spec twice. */
6174 {
6178 {
6195 }
6197 {
6198 Node_Id gnat_body
6201 /* Retrieve compilation unit node of generic body. */
6206 /* If body is available, elaborate its context. */
6209 }
6210 }
6214 }
6215 \f
6216 /* Do the processing of GNAT_NODE, an N_Freeze_Entity. */
6218 static void
6220 {
6225 /* If this is a package, we need to generate code for the package. */
6227 {
6228 insert_code_for
6232 }
6234 /* Don't do anything for class-wide types as they are always transformed
6235 into their root type. */
6239 /* Check for an old definition. This freeze node might be for an Itype. */
6240 gnu_old
6243 /* If this entity has an address representation clause, GNU_OLD is the
6244 address, so discard it here. */
6248 /* Don't do anything for subprograms that may have been elaborated before
6249 their freeze nodes. This can happen, for example, because of an inner
6250 call in an instance body or because of previous compilation of a spec
6251 for inlining purposes. */
6259 /* If we have a non-dummy type old tree, we have nothing to do, except
6260 aborting if this is the public view of a private type whose full view was
6261 not delayed, as this node was never delayed as it should have been. We
6262 let this happen for concurrent types and their Corresponding_Record_Type,
6263 however, because each might legitimately be elaborated before its own
6264 freeze node, e.g. while processing the other. */
6268 {
6276 }
6278 /* Reset the saved tree, if any, and elaborate the object or type for real.
6279 If there is a full view, elaborate it and use the result. And, if this
6280 is the root type of a class-wide type, reuse it for the latter. */
6282 {
6292 }
6296 {
6299 /* Propagate back-annotations from full view to partial view. */
6309 /* The above call may have defined this entity (the simplest example
6310 of this is when we have a private enumeral type since the bounds
6311 will have the public view). */
6314 }
6315 else
6316 {
6317 tree gnu_init
6323 }
6330 /* If we've made any pointers to the old version of this type, we
6331 have to update them. */
6335 }
6336 \f
6337 /* Elaborate decls in the lists GNAT_DECLS and GNAT_DECLS2, if present.
6338 We make two passes, one to elaborate anything other than bodies (but
6339 we declare a function if there was no spec). The second pass
6340 elaborates the bodies.
6342 GNAT_END_LIST gives the element in the list past the end. Normally,
6343 this is Empty, but can be First_Real_Statement for a
6344 Handled_Sequence_Of_Statements.
6346 We make a complete pass through both lists if PASS1P is true, then make
6347 the second pass over both lists if PASS2P is true. The lists usually
6348 correspond to the public and private parts of a package. */
6350 static void
6353 {
6355 Node_Id gnat_decl;
6365 {
6366 /* For package specs, we recurse inside the declarations,
6367 thus taking the two pass approach inside the boundary. */
6375 /* Similarly for any declarations in the actions of a
6376 freeze node. */
6378 {
6381 }
6383 /* Package bodies with freeze nodes get their elaboration deferred
6384 until the freeze node, but the code must be placed in the right
6385 place, so record the code position now. */
6393 (Corresponding_Spec
6396 record_code_position
6399 /* We defer most subprogram bodies to the second pass. */
6401 {
6403 {
6409 }
6410 }
6412 /* For bodies and stubs that act as their own specs, the entity
6413 itself must be elaborated in the first pass, because it may
6414 be used in other declarations. */
6416 {
6417 Node_Id gnat_subprog_id
6424 }
6426 /* Concurrent stubs stand for the corresponding subprogram bodies,
6427 which are deferred like other bodies. */
6430 ;
6432 else
6434 }
6436 /* Here we elaborate everything we deferred above except for package bodies,
6437 which are elaborated at their freeze nodes. Note that we must also
6438 go inside things (package specs and freeze nodes) the first pass did. */
6444 {
6460 }
6461 }
6462 \f
6463 /* Make a unary operation of kind CODE using build_unary_op, but guard
6464 the operation by an overflow check. CODE can be one of NEGATE_EXPR
6465 or ABS_EXPR. GNU_TYPE is the type desired for the result. Usually
6466 the operation is to be performed in that type. GNAT_NODE is the gnat
6467 node conveying the source location for which the error should be
6468 signaled. */
6470 static tree
6472 Node_Id gnat_node)
6473 {
6482 }
6484 /* Make a binary operation of kind CODE using build_binary_op, but guard
6485 the operation by an overflow check. CODE can be one of PLUS_EXPR,
6486 MINUS_EXPR or MULT_EXPR. GNU_TYPE is the type desired for the result.
6487 Usually the operation is to be performed in that type. GNAT_NODE is
6488 the GNAT node conveying the source location for which the error should
6489 be signaled. */
6491 static tree
6494 {
6499 tree gnu_expr;
6502 tree rhs_lt_zero;
6503 tree check_pos;
6504 tree check_neg;
6505 tree check;
6510 /* Prefer a constant or known-positive rhs to simplify checks. */
6515 {
6519 }
6522 ? boolean_false_node
6525 /* ??? Should use more efficient check for operand_equal_p (lhs, rhs, 0) */
6527 /* Try a few strategies that may be cheaper than the general
6528 code at the end of the function, if the rhs is not known.
6529 The strategies are:
6530 - Call library function for 64-bit multiplication (complex)
6531 - Widen, if input arguments are sufficiently small
6532 - Determine overflow using wrapped result for addition/subtraction. */
6535 {
6536 /* Even for add/subtract double size to get another base type. */
6540 {
6546 }
6551 {
6558 tree check = build_binary_op
6567 return
6569 }
6572 {
6574 tree wrapped_expr = convert
6579 tree result = convert
6582 /* Overflow when (rhs < 0) ^ (wrapped_expr < lhs)), for addition
6583 or when (rhs < 0) ^ (wrapped_expr > lhs) for subtraction. */
6584 tree check = build_binary_op
6589 return
6591 }
6592 }
6595 {
6597 /* When rhs >= 0, overflow when lhs > type_max - rhs. */
6602 /* When rhs < 0, overflow when lhs < type_min - rhs. */
6609 /* When rhs >= 0, overflow when lhs < type_min + rhs. */
6614 /* When rhs < 0, overflow when lhs > type_max + rhs. */
6621 /* The check here is designed to be efficient if the rhs is constant,
6622 but it will work for any rhs by using integer division.
6623 Four different check expressions determine wether X * C overflows,
6624 depending on C.
6625 C == 0 => false
6626 C > 0 => X > type_max / C || X < type_min / C
6627 C == -1 => X == type_min
6628 C < -1 => X > type_min / C || X < type_max / C */
6633 check_pos
6636 rhs),
6639 boolean_type_node,
6642 boolean_type_node,
6645 check_neg
6650 type_min),
6653 boolean_type_node,
6656 boolean_type_node,
6662 }
6666 /* If we can fold the expression to a constant, just return it.
6667 The caller will deal with overflow, no need to generate a check. */
6672 check_pos);
6675 }
6677 /* Emit code for a range check. GNU_EXPR is the expression to be checked,
6678 GNAT_RANGE_TYPE the gnat type or subtype containing the bounds against
6679 which we have to check. GNAT_NODE is the GNAT node conveying the source
6680 location for which the error should be signaled. */
6682 static tree
6684 {
6690 /* If GNU_EXPR has GNAT_RANGE_TYPE as its base type, no check is needed.
6691 This can for example happen when translating 'Val or 'Value. */
6695 /* If GNU_EXPR has an integral type that is narrower than GNU_RANGE_TYPE,
6696 we can't do anything since we might be truncating the bounds. No
6697 check is needed in this case. */
6703 /* Checked expressions must be evaluated only once. */
6706 /* Note that the form of the check is
6707 (not (expr >= lo)) or (not (expr <= hi))
6708 the reason for this slightly convoluted form is that NaNs
6709 are not considered to be in range in the float case. */
6710 return emit_check
6712 invert_truthvalue
6716 invert_truthvalue
6720 gnu_high)))),
6722 }
6723 \f
6724 /* Emit code for an index check. GNU_ARRAY_OBJECT is the array object which
6725 we are about to index, GNU_EXPR is the index expression to be checked,
6726 GNU_LOW and GNU_HIGH are the lower and upper bounds against which GNU_EXPR
6727 has to be checked. Note that for index checking we cannot simply use the
6728 emit_range_check function (although very similar code needs to be generated
6729 in both cases) since for index checking the array type against which we are
6730 checking the indices may be unconstrained and consequently we need to get
6731 the actual index bounds from the array object itself (GNU_ARRAY_OBJECT).
6732 The place where we need to do that is in subprograms having unconstrained
6733 array formal parameters. GNAT_NODE is the GNAT node conveying the source
6734 location for which the error should be signaled. */
6736 static tree
6739 {
6740 tree gnu_expr_check;
6742 /* Checked expressions must be evaluated only once. */
6745 /* Must do this computation in the base type in case the expression's
6746 type is an unsigned subtypes. */
6749 /* If GNU_LOW or GNU_HIGH are a PLACEHOLDER_EXPR, qualify them by
6750 the object we are handling. */
6754 return emit_check
6757 gnu_expr_check,
6759 gnu_low)),
6761 gnu_expr_check,
6763 gnu_high))),
6765 }
6766 \f
6767 /* GNU_COND contains the condition corresponding to an access, discriminant or
6768 range check of value GNU_EXPR. Build a COND_EXPR that returns GNU_EXPR if
6769 GNU_COND is false and raises a CONSTRAINT_ERROR if GNU_COND is true.
6770 REASON is the code that says why the exception was raised. GNAT_NODE is
6771 the GNAT node conveying the source location for which the error should be
6772 signaled. */
6774 static tree
6776 {
6777 tree gnu_call
6779 tree gnu_result
6783 gnu_expr);
6785 /* GNU_RESULT has side effects if and only if GNU_EXPR has:
6786 we don't need to evaluate it just for the check. */
6790 }
6791 \f
6792 /* Return an expression that converts GNU_EXPR to GNAT_TYPE, doing overflow
6793 checks if OVERFLOW_P is true and range checks if RANGE_P is true.
6794 GNAT_TYPE is known to be an integral type. If TRUNCATE_P true, do a
6795 float to integer conversion with truncation; otherwise round.
6796 GNAT_NODE is the GNAT node conveying the source location for which the
6797 error should be signaled. */
6799 static tree
6802 {
6809 /* If we are not doing any checks, the output is an integral type, and
6810 the input is not a floating type, just do the conversion. This
6811 shortcut is required to avoid problems with packed array types
6812 and simplifies code in all cases anyway. */
6817 /* First convert the expression to its base type. This
6818 will never generate code, but makes the tests below much simpler.
6819 But don't do this if converting from an integer type to an unconstrained
6820 array type since then we need to get the bounds from the original
6821 (unpacked) type. */
6825 /* If overflow checks are requested, we need to be sure the result will
6826 fit in the output base type. But don't do this if the input
6827 is integer and the output floating-point. */
6830 {
6831 /* Ensure GNU_EXPR only gets evaluated once. */
6839 /* Convert the lower bounds to signed types, so we're sure we're
6840 comparing them properly. Likewise, convert the upper bounds
6841 to unsigned types. */
6855 /* Check each bound separately and only if the result bound
6856 is tighter than the bound on the input type. Note that all the
6857 types are base types, so the bounds must be constant. Also,
6858 the comparison is done in the base type of the input, which
6859 always has the proper signedness. First check for input
6860 integer (which means output integer), output float (which means
6861 both float), or mixed, in which case we always compare.
6862 Note that we have to do the comparison which would *fail* in the
6863 case of an error since if it's an FP comparison and one of the
6864 values is a NaN or Inf, the comparison will fail. */
6871 gnu_cond
6872 = invert_truthvalue
6875 gnu_out_lb)));
6883 gnu_cond
6885 invert_truthvalue
6887 gnu_input,
6889 gnu_out_ub))));
6894 }
6896 /* Now convert to the result base type. If this is a non-truncating
6897 float-to-integer conversion, round. */
6900 {
6906 /* The following calculations depend on proper rounding to even
6907 of each arithmetic operation. In order to prevent excess
6908 precision from spoiling this property, use the widest hardware
6909 floating-point type if FP_ARITH_MAY_WIDEN is true. */
6910 calc_type
6913 /* FIXME: Should not have padding in the first place. */
6917 /* Compute the exact value calc_type'Pred (0.5) at compile time. */
6921 half_minus_pred_half);
6924 /* If the input is strictly negative, subtract this value
6925 and otherwise add it from the input. For 0.5, the result
6926 is exactly between 1.0 and the machine number preceding 1.0
6927 (for calc_type). Since the last bit of 1.0 is even, this 0.5
6928 will round to 1.0, while all other number with an absolute
6929 value less than 0.5 round to 0.0. For larger numbers exactly
6930 halfway between integers, rounding will always be correct as
6931 the true mathematical result will be closer to the higher
6932 integer compared to the lower one. So, this constant works
6933 for all floating-point numbers.
6935 The reason to use the same constant with subtract/add instead
6936 of a positive and negative constant is to allow the comparison
6937 to be scheduled in parallel with retrieval of the constant and
6938 conversion of the input to the calc_type (if necessary). */
6943 gnu_comp
6945 gnu_add_pred_half
6947 gnu_subtract_pred_half
6951 }
6957 else
6960 /* Finally, do the range check if requested. Note that if the result type
6961 is a modular type, the range check is actually an overflow check. */
6968 }
6969 \f
6970 /* Return true if TYPE is a smaller form of ORIG_TYPE. */
6972 static bool
6974 {
6977 /* We're not interested in variants here. */
6981 /* Like a variant, a packable version keeps the original TYPE_NAME. */
6992 }
6994 /* Return true if GNU_EXPR can be directly addressed. This is the case
6995 unless it is an expression involving computation or if it involves a
6996 reference to a bitfield or to an object not sufficiently aligned for
6997 its type. If GNU_TYPE is non-null, return true only if GNU_EXPR can
6998 be directly addressed as an object of this type.
7000 *** Notes on addressability issues in the Ada compiler ***
7002 This predicate is necessary in order to bridge the gap between Gigi
7003 and the middle-end about addressability of GENERIC trees. A tree
7004 is said to be addressable if it can be directly addressed, i.e. if
7005 its address can be taken, is a multiple of the type's alignment on
7006 strict-alignment architectures and returns the first storage unit
7007 assigned to the object represented by the tree.
7009 In the C family of languages, everything is in practice addressable
7010 at the language level, except for bit-fields. This means that these
7011 compilers will take the address of any tree that doesn't represent
7012 a bit-field reference and expect the result to be the first storage
7013 unit assigned to the object. Even in cases where this will result
7014 in unaligned accesses at run time, nothing is supposed to be done
7015 and the program is considered as erroneous instead (see PR c/18287).
7017 The implicit assumptions made in the middle-end are in keeping with
7018 the C viewpoint described above:
7019 - the address of a bit-field reference is supposed to be never
7020 taken; the compiler (generally) will stop on such a construct,
7021 - any other tree is addressable if it is formally addressable,
7022 i.e. if it is formally allowed to be the operand of ADDR_EXPR.
7024 In Ada, the viewpoint is the opposite one: nothing is addressable
7025 at the language level unless explicitly declared so. This means
7026 that the compiler will both make sure that the trees representing
7027 references to addressable ("aliased" in Ada parlance) objects are
7028 addressable and make no real attempts at ensuring that the trees
7029 representing references to non-addressable objects are addressable.
7031 In the first case, Ada is effectively equivalent to C and handing
7032 down the direct result of applying ADDR_EXPR to these trees to the
7033 middle-end works flawlessly. In the second case, Ada cannot afford
7034 to consider the program as erroneous if the address of trees that
7035 are not addressable is requested for technical reasons, unlike C;
7036 as a consequence, the Ada compiler must arrange for either making
7037 sure that this address is not requested in the middle-end or for
7038 compensating by inserting temporaries if it is requested in Gigi.
7040 The first goal can be achieved because the middle-end should not
7041 request the address of non-addressable trees on its own; the only
7042 exception is for the invocation of low-level block operations like
7043 memcpy, for which the addressability requirements are lower since
7044 the type's alignment can be disregarded. In practice, this means
7045 that Gigi must make sure that such operations cannot be applied to
7046 non-BLKmode bit-fields.
7048 The second goal is achieved by means of the addressable_p predicate
7049 and by inserting SAVE_EXPRs around trees deemed non-addressable.
7050 They will be turned during gimplification into proper temporaries
7051 whose address will be used in lieu of that of the original tree. */
7053 static bool
7055 {
7056 /* For an integral type, the size of the actual type of the object may not
7057 be greater than that of the expected type, otherwise an indirect access
7058 in the latter type wouldn't correctly set all the bits of the object. */
7064 /* The size of the actual type of the object may not be smaller than that
7065 of the expected type, otherwise an indirect access in the latter type
7066 would be larger than the object. But only record types need to be
7067 considered in practice for this case. */
7074 {
7079 /* All DECLs are addressable: if they are in a register, we can force
7080 them to memory. */
7085 /* Taking the address of a dereference yields the original pointer. */
7090 /* Taking the address yields a pointer to the constant pool. */
7094 /* Taking the address of a static constructor yields a pointer to the
7095 tree constant pool. */
7107 /* All rvalues are deemed addressable since taking their address will
7108 force a temporary to be created by the middle-end. */
7112 /* The address of a compound expression is that of its 2nd operand. */
7116 /* We accept &COND_EXPR as soon as both operands are addressable and
7117 expect the outcome to be the address of the selected operand. */
7123 /* Even with DECL_BIT_FIELD cleared, we have to ensure that
7124 the field is sufficiently aligned, in case it is subject
7125 to a pragma Component_Alignment. But we don't need to
7126 check the alignment of the containing record, as it is
7127 guaranteed to be not smaller than that of its most
7128 aligned field that is not a bit-field. */
7129 && (!STRICT_ALIGNMENT
7132 /* The field of a padding record is always addressable. */
7146 {
7147 /* This is addressable if we can avoid a copy. */
7151 && (!STRICT_ALIGNMENT
7156 && (!STRICT_ALIGNMENT
7162 }
7166 }
7167 }
7168 \f
7169 /* Do the processing for the declaration of a GNAT_ENTITY, a type. If
7170 a separate Freeze node exists, delay the bulk of the processing. Otherwise
7171 make a GCC type for GNAT_ENTITY and set up the correspondence. */
7173 void
7175 {
7176 tree gnu_old
7178 tree gnu_new;
7180 /* If we are to delay elaboration of this type, just do any
7181 elaborations needed for expressions within the declaration and
7182 make a dummy type entry for this node and its Full_View (if
7183 any) in case something points to it. Don't do this if it
7184 has already been done (the only way that can happen is if
7185 the private completion is also delayed). */
7191 {
7195 {
7201 }
7204 }
7206 /* If we saved away a dummy type for this node it means that this
7207 made the type that corresponds to the full type of an incomplete
7208 type. Clear that type for now and then update the type in the
7209 pointers. */
7211 {
7216 }
7218 /* Now fully elaborate the type. */
7222 /* If we have an old type and we've made pointers to this type,
7223 update those pointers. */
7228 /* If this is a record type corresponding to a task or protected type
7229 that is a completion of an incomplete type, perform a similar update
7230 on the type. ??? Including protected types here is a guess. */
7234 {
7235 tree gnu_task_old
7245 }
7246 }
7247 \f
7248 /* GNAT_ENTITY is the type of the resulting constructors,
7249 GNAT_ASSOC is the front of the Component_Associations of an N_Aggregate,
7250 and GNU_TYPE is the GCC type of the corresponding record.
7252 Return a CONSTRUCTOR to build the record. */
7254 static tree
7256 {
7259 /* We test for GNU_FIELD being empty in the case where a variant
7260 was the last thing since we don't take things off GNAT_ASSOC in
7261 that case. We check GNAT_ASSOC in case we have a variant, but it
7262 has no fields. */
7266 {
7271 /* The expander is supposed to put a single component selector name
7272 in every record component association. */
7275 /* Ignore fields that have Corresponding_Discriminants since we'll
7276 be setting that field in the parent. */
7281 /* Also ignore discriminants of Unchecked_Unions. */
7286 /* Before assigning a value in an aggregate make sure range checks
7287 are done if required. Then convert to the type of the field. */
7293 /* Add the field and expression to the list. */
7295 }
7299 #ifdef ENABLE_CHECKING
7300 {
7301 tree gnu_field;
7303 /* Verify every entry in GNU_LIST was used. */
7306 }
7307 #endif
7310 }
7312 /* Build a possibly nested constructor for array aggregates. GNAT_EXPR is
7313 the first element of an array aggregate. It may itself be an aggregate.
7314 GNU_ARRAY_TYPE is the GCC type corresponding to the array aggregate.
7315 GNAT_COMPONENT_TYPE is the type of the array component; it is needed
7316 for range checking. */
7318 static tree
7320 Entity_Id gnat_component_type)
7321 {
7323 tree gnu_expr;
7327 {
7328 /* If the expression is itself an array aggregate then first build the
7329 innermost constructor if it is part of our array (multi-dimensional
7330 case). */
7336 gnat_component_type);
7337 else
7338 {
7341 /* Before assigning the element to the array, make sure it is
7342 in range. */
7345 }
7351 }
7354 }
7355 \f
7356 /* Subroutine of assoc_to_constructor: VALUES is a list of field associations,
7357 some of which are from RECORD_TYPE. Return a CONSTRUCTOR consisting
7358 of the associations that are from RECORD_TYPE. If we see an internal
7359 record, make a recursive call to fill it in as well. */
7361 static tree
7363 {
7368 {
7371 /* _Parent is an internal field, but may have values in the aggregate,
7372 so check for values first. */
7374 {
7377 }
7380 {
7385 }
7386 else
7387 /* If we have a record subtype, the names will match, but not the
7388 actual FIELD_DECLs. */
7391 {
7394 }
7400 }
7403 }
7404 \f
7405 /* EXP is to be treated as an array or record. Handle the cases when it is
7406 an access object and perform the required dereferences. */
7408 static tree
7410 {
7411 /* If the type is a pointer, dereference it. */
7416 /* If we got a padded type, remove it too. */
7421 }
7422 \f
7423 /* Convert SLOC into LOCUS. Return true if SLOC corresponds to a source code
7424 location and false if it doesn't. In the former case, set the Gigi global
7425 variable REF_FILENAME to the simple debug file name as given by sinput. */
7427 bool
7429 {
7434 {
7437 }
7438 else
7439 {
7445 /* Translate the location according to the line-map.h formula. */
7449 }
7451 ref_filename
7452 = IDENTIFIER_POINTER
7453 (get_identifier
7457 }
7459 /* Similar to set_expr_location, but start with the Sloc of GNAT_NODE and
7460 don't do anything if it doesn't correspond to a source location. */
7462 static void
7464 {
7465 location_t locus;
7471 }
7473 /* More elaborate version of set_expr_location_from_node to be used in more
7474 general contexts, for example the result of the translation of a generic
7475 GNAT node. */
7477 static void
7479 {
7480 /* Set the location information on the node if it is a real expression.
7481 References can be reused for multiple GNAT nodes and they would get
7482 the location information of their last use. Also make sure not to
7483 overwrite an existing location as it is probably more precise. */
7486 {
7487 CASE_CONVERT:
7495 /* ... fall through ... */
7501 }
7502 }
7503 \f
7504 /* Return a colon-separated list of encodings contained in encoded Ada
7505 name. */
7509 {
7513 }
7515 /* Extract the Ada name from an encoded name. */
7519 {
7523 }
7524 \f
7525 /* Post an error message. MSG is the error message, properly annotated.
7526 NODE is the node at which to post the error and the node to use for the
7527 '&' substitution. */
7529 void
7531 {
7532 String_Template temp;
7533 Fat_Pointer fp;
7539 }
7541 /* Similar to post_error, but NODE is the node at which to post the error and
7542 ENT is the node to use for the '&' substitution. */
7544 void
7546 {
7547 String_Template temp;
7548 Fat_Pointer fp;
7554 }
7556 /* Similar to post_error_ne, but NUM is the number to use for the '^'. */
7558 void
7560 {
7563 }
7564 \f
7565 /* Similar to post_error_ne, but T is a GCC tree representing the number to
7566 write. If T represents a constant, the text inside curly brackets in
7567 MSG will be output (presumably including a '^'). Otherwise it will not
7568 be output and the text inside square brackets will be output instead. */
7570 void
7572 {
7579 {
7582 }
7583 else
7587 {
7593 ;
7594 else
7596 }
7601 }
7603 /* Similar to post_error_ne_tree, but NUM is a second integer to write. */
7605 void
7608 {
7611 }
7612 \f
7613 /* Initialize the table that maps GNAT codes to GCC codes for simple
7614 binary and unary operations. */
7616 static void
7618 {
7644 }
7646 /* Return a label to branch to for the exception type in KIND or NULL_TREE
7647 if none. */
7649 tree
7651 {
7658 else
7660 }