| blob | 689f072d81689345d68fd7bb2f414a380f49a2d7 |
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 variable for the return value of a function with copy-in/copy-out
169 parameters. See processing for N_Subprogram_Body. */
172 /* Stack of LOOP_STMT nodes. */
175 /* The stacks for N_{Push,Pop}_*_Label. */
180 /* Map GNAT tree codes to GCC tree codes for simple expressions. */
212 /* Hooks for debug info back-ends, only supported and used in a restricted set
213 of configurations. */
216 \f
217 /* This is the main program of the back-end. It sets up all the table
218 structures and then generates code. */
220 void
230 {
231 Entity_Id gnat_literal;
252 /* Declare the name of the compilation unit as the first global
253 name in order to make the middle-end fully deterministic. */
258 {
259 /* Use the identifier table to make a permanent copy of the filename as
260 the name table gets reallocated after Gigi returns but before all the
261 debugging information is output. The __gnat_to_canonical_file_spec
262 call translates filenames from pragmas Source_Reference that contain
263 host style syntax not understood by gdb. */
265 = IDENTIFIER_POINTER
266 (get_identifier
267 (__gnat_to_canonical_file_spec
270 /* We rely on the order isomorphism between files and line maps. */
273 /* We create the line map for a source file at once, with a fixed number
274 of columns chosen to avoid jumping over the next power of 2. */
279 }
281 /* Initialize ourselves. */
286 /* If we are just annotating types, give VOID_TYPE zero sizes to avoid
287 errors. */
289 {
292 }
294 /* Enable GNAT stack checking method if needed */
298 /* Retrieve alignment settings. */
302 /* Record the builtin types. Define `integer' and `character' first so that
303 dbx will output them first. */
309 /* Save the type we made for integer as the type for Standard.Integer. */
314 /* Likewise for character as the type for Standard.Character. */
319 /* Likewise for boolean as the type for Standard.Boolean. */
343 /* Now declare run-time functions. */
346 /* malloc is a function declaration tree for a function to allocate
347 memory. */
348 malloc_decl
356 /* malloc32 is a function declaration tree for a function to allocate
357 32-bit memory on a 64-bit system. Needed only on 64-bit VMS. */
358 malloc32_decl
366 /* free is a function declaration tree for a function to free memory. */
367 free_decl
371 ptr_void_type_node,
372 t)),
375 /* This is used for 64-bit multiplication with overflow checking. */
376 mulv64_decl
382 /* Name of the _Parent field in tagged record types. */
385 /* Name of the Exception_Data type defined in System.Standard_Library. */
386 exception_data_name_id
389 /* Make the types and functions used for exception processing. */
390 jmpbuf_type
396 /* Functions to get and set the jumpbuf pointer for the current thread. */
397 get_jmpbuf_decl
398 = create_subprog_decl
404 set_jmpbuf_decl
405 = create_subprog_decl
407 NULL_TREE,
413 /* setjmp returns an integer and has one operand, which is a pointer to
414 a jmpbuf. */
415 setjmp_decl
416 = create_subprog_decl
424 /* update_setjmp_buf updates a setjmp buffer from the current stack pointer
425 address. */
426 update_setjmp_buf_decl
427 = create_subprog_decl
435 /* Hooks to call when entering/leaving an exception handler. */
436 begin_handler_decl
440 ptr_void_type_node,
441 t)),
445 end_handler_decl
449 ptr_void_type_node,
450 t)),
454 /* If in no exception handlers mode, all raise statements are redirected to
455 __gnat_last_chance_handler. No need to redefine raise_nodefer_decl since
456 this procedure will never be called in this mode. */
458 {
459 tree decl
460 = create_subprog_decl
464 build_pointer_type
467 integer_type_node,
468 t))),
476 }
477 else
478 {
479 /* Otherwise, make one decl for each exception reason. */
485 i == CE_Index_Check_Failed
489 }
491 /* Set the types that GCC and Gigi use from the front end. */
492 exception_type
496 /* Make other functions used for exception processing. */
497 get_excptr_decl
498 = create_subprog_decl
500 NULL_TREE,
504 raise_nodefer_decl
505 = create_subprog_decl
510 t)),
513 /* Indicate that these never return. */
518 TYPE_QUAL_VOLATILE);
520 /* Build the special descriptor type and its null node if needed. */
522 {
531 TARGET_VTABLE_USES_DESCRIPTORS);
536 {
537 tree field
544 elt--;
545 }
550 }
552 long_long_float_type
556 {
557 /* In this case, the builtin floating point types are VAX float,
558 so make up a type for use. */
563 }
564 else
567 /* Dummy objects to materialize "others" and "all others" in the exception
568 tables. These are exported by a-exexpr.adb, so see this unit for the
569 types to use. */
570 others_decl
576 all_others_decl
584 /* Install the builtins we might need, either internally or as
585 user available facilities for Intrinsic imports. */
593 /* Process any Pragma Ident for the main unit. */
594 #ifdef ASM_OUTPUT_IDENT
596 ASM_OUTPUT_IDENT
599 #endif
601 /* If we are using the GCC exception mechanism, let GCC know. */
605 /* Now translate the compilation unit proper. */
608 /* Finally see if we have any elaboration procedures to deal with. */
610 {
613 /* We should have a BIND_EXPR but it may not have any statements in it.
614 If it doesn't have any, we have nothing to do except for setting the
615 flag on the GNAT node. Otherwise, process the function as others. */
621 else
622 {
625 }
626 }
628 /* We cannot track the location of errors past this point. */
630 }
631 \f
632 /* Return a subprogram decl corresponding to __gnat_rcheck_xx for the given
633 CHECK (if EXTENDED is false), or __gnat_rcheck_xx_ext (if EXTENDED is
634 true). */
636 static tree
638 {
640 tree result;
643 {
645 result
646 = create_subprog_decl
648 build_function_type
650 tree_cons
654 kind == exception_column
655 ? void_tree
658 integer_type_node,
659 void_tree)))))),
661 }
662 else
663 {
665 result
666 = create_subprog_decl
668 build_function_type
670 tree_cons
674 }
682 }
683 \f
684 /* Return a positive value if an lvalue is required for GNAT_NODE, which is
685 an N_Attribute_Reference. */
687 static int
689 {
691 {
726 }
727 }
729 /* Return a positive value if an lvalue is required for GNAT_NODE. GNU_TYPE
730 is the type that will be used for GNAT_NODE in the translated GNU tree.
731 CONSTANT indicates whether the underlying object represented by GNAT_NODE
732 is constant in the Ada sense. If it is, ADDRESS_OF_CONSTANT indicates
733 whether its value is the address of a constant and ALIASED whether it is
734 aliased. If it isn't, ADDRESS_OF_CONSTANT and ALIASED are ignored.
736 The function climbs up the GNAT tree starting from the node and returns 1
737 upon encountering a node that effectively requires an lvalue downstream.
738 It returns int instead of bool to facilitate usage in non-purely binary
739 logic contexts. */
741 static int
744 {
748 {
758 /* If the parameter is by reference, an lvalue is required. */
764 /* Only the array expression can require an lvalue. */
768 /* ??? Consider that referencing an indexed component with a
769 non-constant index forces the whole aggregate to memory.
770 Note that N_Integer_Literal is conservative, any static
771 expression in the RM sense could probably be accepted. */
778 /* ... fall through ... */
781 /* Only the array expression can require an lvalue. */
795 /* We need to make a real renaming only if the constant object is
796 aliased or if we may use a renaming pointer; otherwise we can
797 optimize and return the rvalue. We make an exception if the object
798 is an identifier since in this case the rvalue can be propagated
799 attached to the CONST_DECL. */
801 || aliased
802 /* This should match the constant case of the renaming code. */
803 || Is_Composite_Type
808 /* We cannot use a constructor if this is an atomic object because
809 the actual assignment might end up being done component-wise. */
813 /* We don't use a constructor if this is a class-wide object
814 because the effective type of the object is the equivalent
815 type of the class-wide subtype and it smashes most of the
816 data into an array of bytes to which we cannot convert. */
821 /* We cannot use a constructor if the LHS is an atomic object because
822 the actual assignment might end up being done component-wise. */
832 /* ... fall through ... */
836 /* We must look through all conversions because we may need to bypass
837 an intermediate conversion that is meant to be purely formal. */
843 /* We should only reach here through the N_Qualified_Expression case.
844 Force an lvalue for composite types since a block-copy to the newly
845 allocated area of memory is made. */
849 /* We look through dereferences for address of constant because we need
850 to handle the special cases listed above. */
856 /* ... fall through ... */
860 }
863 }
865 /* Subroutine of gnat_to_gnu to translate gnat_node, an N_Identifier,
866 to a GCC tree, which is returned. GNU_RESULT_TYPE_P is a pointer
867 to where we should place the result type. */
869 static tree
871 {
875 /* Whether we should require an lvalue for GNAT_NODE. Needed in
876 specific circumstances only, so evaluated lazily. < 0 means
877 unknown, > 0 means known true, 0 means known false. */
880 /* If GNAT_NODE is a constant, whether we should use the initialization
881 value instead of the constant entity, typically for scalars with an
882 address clause when the parent doesn't require an lvalue. */
885 /* If the Etype of this node does not equal the Etype of the Entity,
886 something is wrong with the entity map, probably in generic
887 instantiation. However, this does not apply to types. Since we sometime
888 have strange Ekind's, just do this test for objects. Also, if the Etype of
889 the Entity is private, the Etype of the N_Identifier is allowed to be the
890 full type and also we consider a packed array type to be the same as the
891 original type. Similarly, a class-wide type is equivalent to a subtype of
892 itself. Finally, if the types are Itypes, one may be a copy of the other,
893 which is also legal. */
916 /* If this is a reference to a deferred constant whose partial view is an
917 unconstrained private type, the proper type is on the full view of the
918 constant, not on the full view of the type, which may be unconstrained.
920 This may be a reference to a type, for example in the prefix of the
921 attribute Position, generated for dispatching code (see Make_DT in
922 exp_disp,adb). In that case we need the type itself, not is parent,
923 in particular if it is a derived type */
928 {
931 }
932 else
933 {
934 /* We want to use the Actual_Subtype if it has already been elaborated,
935 otherwise the Etype. Avoid using Actual_Subtype for packed arrays to
936 simplify things. */
944 else
946 }
948 /* Expand the type of this identifier first, in case it is an enumeral
949 literal, which only get made when the type is expanded. There is no
950 order-of-elaboration issue here. */
953 /* If this is a non-imported scalar constant with an address clause,
954 retrieve the value instead of a pointer to be dereferenced unless
955 an lvalue is required. This is generally more efficient and actually
956 required if this is a static expression because it might be used
957 in a context where a dereference is inappropriate, such as a case
958 statement alternative or a record discriminant. There is no possible
959 volatile-ness short-circuit here since Volatile constants must be
960 imported per C.6. */
965 {
969 }
972 {
973 /* If this is a deferred constant, the initializer is attached to
974 the full view. */
979 }
980 else
983 /* If we are in an exception handler, force this variable into memory to
984 ensure optimization does not remove stores that appear redundant but are
985 actually needed in case an exception occurs.
987 ??? Note that we need not do this if the variable is declared within the
988 handler, only if it is referenced in the handler and declared in an
989 enclosing block, but we have no way of testing that right now.
991 ??? We used to essentially set the TREE_ADDRESSABLE flag on the variable
992 here, but it can now be removed by the Tree aliasing machinery if the
993 address of the variable is never taken. All we can do is to make the
994 variable volatile, which might incur the generation of temporaries just
995 to access the memory in some circumstances. This can be avoided for
996 variables of non-constant size because they are automatically allocated
997 to memory. There might be no way of allocating a proper temporary for
998 them in any case. We only do this for SJLJ though. */
1004 /* Some objects (such as parameters passed by reference, globals of
1005 variable size, and renamed objects) actually represent the address
1006 of the object. In that case, we must do the dereference. Likewise,
1007 deal with parameters to foreign convention subprograms. */
1012 {
1014 tree renamed_obj;
1018 {
1022 }
1026 {
1027 gnu_result
1030 gnu_result));
1033 }
1035 /* If it's a renaming pointer and we are at the right binding level,
1036 we can reference the renamed object directly, since the renamed
1037 expression has been protected against multiple evaluations. */
1044 /* Return the underlying CST for a CONST_DECL like a few lines below,
1045 after dereferencing in this case. */
1050 else
1051 {
1055 }
1059 }
1061 /* The GNAT tree has the type of a function as the type of its result. Also
1062 use the type of the result if the Etype is a subtype which is nominally
1063 unconstrained. But remove any padding from the resulting type. */
1066 {
1070 }
1072 /* If we have a constant declaration and its initializer, try to return the
1073 latter to avoid the need to call fold in lots of places and the need for
1074 elaboration code if this identifier is used as an initializer itself. */
1078 {
1084 /* If there is a (corresponding) variable or this is the address of a
1085 constant, we only want to return the initializer if an lvalue isn't
1086 required. Evaluate this now if we have not already done so. */
1088 require_lvalue
1092 /* ??? We need to unshare the initializer if the object is external
1093 as such objects are not marked for unsharing if we are not at the
1094 global level. This should be fixed in add_decl_expr. */
1097 }
1102 }
1103 \f
1104 /* Subroutine of gnat_to_gnu to process gnat_node, an N_Pragma. Return
1105 any statements we generate. */
1107 static tree
1109 {
1110 Node_Id gnat_temp;
1113 /* Check for (and ignore) unrecognized pragma and do nothing if we are just
1114 annotating types. */
1120 {
1122 /* Do nothing at top level: all such variables are already viewable. */
1129 {
1135 #ifdef ASM_COMMENT_START
1137 #endif
1142 /* Use the value only if it fits into a normal register,
1143 otherwise use the address. */
1152 #ifdef ASM_COMMENT_START
1158 NULL);
1161 #endif
1163 asm_constraint,
1164 NULL_TREE,
1165 tree_cons
1173 }
1179 {
1192 }
1199 }
1202 }
1203 \f
1204 /* Subroutine of gnat_to_gnu to translate GNAT_NODE, an N_Attribute node,
1205 to a GCC tree, which is returned. GNU_RESULT_TYPE_P is a pointer to
1206 where we should place the result type. ATTRIBUTE is the attribute ID. */
1208 static tree
1210 {
1216 /* If the input is a NULL_EXPR, make a new one. */
1218 {
1222 }
1225 {
1228 /* These are just conversions since representation clauses for
1229 enumeration types are handled in the front-end. */
1230 {
1236 }
1241 /* These just add or subtract the constant 1 since representation
1242 clauses for enumeration types are handled in the front-end. */
1247 {
1249 gnu_expr
1250 = emit_check
1252 gnu_expr,
1253 attribute == Attr_Pred
1257 }
1259 gnu_result
1267 /* Conversions don't change addresses but can cause us to miss the
1268 COMPONENT_REF case below, so strip them off. */
1272 /* If we are taking 'Address of an unconstrained object, this is the
1273 pointer to the underlying array. */
1277 /* If we are building a static dispatch table, we have to honor
1278 TARGET_VTABLE_USES_DESCRIPTORS if we want to be compatible
1279 with the C++ ABI. We do it in the non-static case as well,
1280 see gnat_to_gnu_entity, case E_Access_Subprogram_Type. */
1283 {
1285 /* Descriptors can only be built here for top-level functions. */
1293 /* If we're not going to build the descriptor, we have to retrieve
1294 the one which will be built by the linker (or by the compiler
1295 later if a static chain is requested). */
1297 {
1300 gnu_result);
1302 }
1305 TARGET_VTABLE_USES_DESCRIPTORS);
1311 {
1313 {
1317 }
1318 else
1324 elt--;
1325 }
1329 }
1331 /* ... fall through ... */
1337 gnu_result
1344 /* For 'Code_Address, find an inner ADDR_EXPR and mark it so that we
1345 don't try to build a trampoline. */
1347 {
1355 }
1357 /* For other address attributes applied to a nested function,
1358 find an inner ADDR_EXPR and annotate it so that we can issue
1359 a useful warning with -Wtrampolines. */
1361 {
1365 ;
1369 {
1372 /* Check that we're not violating the No_Implicit_Dynamic_Code
1373 restriction. Be conservative if we don't know anything
1374 about the trampoline strategy for the target. */
1376 }
1377 }
1381 {
1382 tree gnu_obj_type;
1387 /* If this is an unconstrained array, we know the object has been
1388 allocated with the template in front of the object. So compute
1389 the template address. */
1391 gnu_ptr
1393 (TYPE_OBJECT_RECORD_TYPE
1395 gnu_ptr);
1400 {
1401 tree gnu_char_ptr_type
1407 }
1410 }
1419 /* Remove NOPs and conversions between original and packable version
1420 from GNU_EXPR, and conversions from GNU_PREFIX. We use GNU_EXPR
1421 to see if a COMPONENT_REF was involved. */
1426 == RECORD_TYPE
1435 /* Replace an unconstrained array type with the type of the underlying
1436 array. We can't do this with a call to maybe_unconstrained_array
1437 since we may have a TYPE_DECL. For 'Max_Size_In_Storage_Elements,
1438 use the record type that will be used to allocate the object and its
1439 template. */
1441 {
1445 }
1447 /* If we're looking for the size of a field, return the field size.
1448 Otherwise, if the prefix is an object, or if we're looking for
1449 'Object_Size or 'Max_Size_In_Storage_Elements, the result is the
1450 GCC size of the type. Otherwise, it is the RM size of the type. */
1456 {
1457 /* If the prefix is an object of a padded type, the GCC size isn't
1458 relevant to the programmer. Normally what we want is the RM size,
1459 which was set from the specified size, but if it was not set, we
1460 want the size of the field. Using the MAX of those two produces
1461 the right result in all cases. Don't use the size of the field
1462 if it's self-referential, since that's never what's wanted. */
1466 {
1470 gnu_result
1473 }
1475 {
1477 Node_Id gnat_actual_subtype
1479 tree gnu_ptr_type
1484 {
1485 tree gnu_actual_obj_type
1487 gnu_type
1489 gnu_actual_obj_type,
1492 }
1495 }
1496 else
1498 }
1499 else
1502 /* Deal with a self-referential size by returning the maximum size for
1503 a type and by qualifying the size with the object otherwise. */
1505 {
1508 else
1510 }
1512 /* If the type contains a template, subtract its size. */
1518 /* For 'Max_Size_In_Storage_Elements, adjust the unit. */
1526 {
1539 else
1540 {
1546 /* If the default alignment of "double" or larger scalar types is
1547 specifically capped and there is an alignment clause neither
1548 on the type nor on the prefix itself, return the cap. */
1550 is_capped_double
1553 is_capped_double
1555 else
1565 else
1567 }
1570 }
1579 {
1586 else
1587 gnu_result
1588 = build_binary_op
1590 build_binary_op
1602 }
1604 /* ... fall through ... */
1607 {
1614 /* Make sure any implicit dereference gets done. */
1617 /* We treat unconstrained array In parameters specially. */
1627 {
1629 tree gnu_type_temp;
1635 ;
1638 }
1645 /* When not optimizing, look up the slot associated with the parameter
1646 and the dimension in the cache and create a new one on failure. */
1648 {
1654 {
1659 }
1660 }
1662 /* Return the cached expression or build a new one. */
1664 {
1666 {
1669 }
1671 gnu_result
1673 }
1676 {
1678 {
1681 }
1683 gnu_result
1685 }
1688 {
1690 {
1693 }
1694 else
1695 {
1696 /* We used to compute the length as max (hb - lb + 1, 0),
1697 which could overflow for some cases of empty arrays, e.g.
1698 when lb == index_type'first. We now compute the length as
1699 (hb >= lb) ? hb - lb + 1 : 0, which would only overflow in
1700 much rarer cases, for extremely large arrays we expect
1701 never to encounter in practice. In addition, the former
1702 computation required the use of potentially constraining
1703 signed arithmetic while the latter doesn't. Note that
1704 the comparison must be done in the original index type,
1705 to avoid any overflow during the conversion. */
1710 gnu_result
1713 comp_type,
1717 gnu_result
1720 boolean_type_node,
1722 gnu_result,
1724 }
1725 }
1727 /* If this has a PLACEHOLDER_EXPR, qualify it by the object we are
1728 handling. Note that these attributes could not have been used on
1729 an unconstrained array type. */
1732 /* Cache the expression we have just computed. Since we want to do it
1733 at run time, we force the use of a SAVE_EXPR and let the gimplifier
1734 create the temporary in the outermost binding level. We will make
1735 sure in Subprogram_Body_to_gnu that it is evaluated on all possible
1736 paths by forcing its evaluation on entry of the function. */
1738 {
1739 gnu_result
1745 else
1747 }
1749 /* Set the source location onto the predicate of the condition in the
1750 'Length case but do not do it if the expression is cached to avoid
1751 messing up the debug info. */
1756 gnat_node);
1759 }
1766 {
1767 HOST_WIDE_INT bitsize;
1768 HOST_WIDE_INT bitpos;
1769 tree gnu_offset;
1770 tree gnu_field_bitpos;
1771 tree gnu_field_offset;
1772 tree gnu_inner;
1780 /* We can have 'Bit on any object, but if it isn't a COMPONENT_REF,
1781 the result is 0. Don't allow 'Bit on a bare component, though. */
1785 {
1788 }
1790 else
1799 {
1807 {
1808 gnu_field_bitpos
1811 gnu_field_offset
1814 }
1815 }
1817 {
1820 }
1821 else
1822 {
1825 }
1828 {
1843 bitsize_one_node);
1849 }
1851 /* If this has a PLACEHOLDER_EXPR, qualify it by the object we are
1852 handling. */
1855 }
1859 {
1867 }
1893 /* Note this size cannot be self-referential. */
1900 /* This is just a zero cast to the pointer type for our prefix and
1901 dereferenced. */
1903 gnu_result
1906 integer_zero_node));
1911 {
1918 {
1923 ;
1924 }
1932 && (DECL_BY_COMPONENT_PTR_P
1936 }
1940 /* Say we have an unimplemented attribute. Then set the value to be
1941 returned to be a zero and hope that's something we can convert to
1942 the type of this attribute. */
1947 }
1949 /* If this is an attribute where the prefix was unused, force a use of it if
1950 it has a side-effect. But don't do it if the prefix is just an entity
1951 name. However, if an access check is needed, we must do it. See second
1952 example in AARM 11.6(5.e). */
1956 gnu_result);
1960 }
1961 \f
1962 /* Subroutine of gnat_to_gnu to translate gnat_node, an N_Case_Statement,
1963 to a GCC tree, which is returned. */
1965 static tree
1967 {
1969 Node_Id gnat_when;
1975 /* The range of values in a case statement is determined by the rules in
1976 RM 5.4(7-9). In almost all cases, this range is represented by the Etype
1977 of the expression. One exception arises in the case of a simple name that
1978 is parenthesized. This still has the Etype of the name, but since it is
1979 not a name, para 7 does not apply, and we need to go to the base type.
1980 This is the only case where parenthesization affects the dynamic
1981 semantics (i.e. the range of possible values at run time that is covered
1982 by the others alternative).
1984 Another exception is if the subtype of the expression is non-static. In
1985 that case, we also have to use the base type. */
1991 /* We build a SWITCH_EXPR that contains the code with interspersed
1992 CASE_LABEL_EXPRs for each label. */
1999 {
2001 Node_Id gnat_choice;
2003 /* First compile all the different case choices for the current WHEN
2004 alternative. */
2007 {
2011 {
2026 /* This represents either a subtype range or a static value of
2027 some kind; Ekind says which. */
2029 {
2035 }
2037 /* ... fall through ... */
2049 }
2051 /* If the case value is a subtype that raises Constraint_Error at
2052 run time because of a wrong bound, then gnu_low or gnu_high is
2053 not translated into an INTEGER_CST. In such a case, we need
2054 to ensure that the when statement is not added in the tree,
2055 otherwise it will crash the gimplifier. */
2058 {
2063 gnat_choice);
2065 }
2066 }
2068 /* Push a binding level here in case variables are declared as we want
2069 them to be local to this set of statements instead of to the block
2070 containing the Case statement. */
2072 {
2077 {
2080 }
2081 }
2082 }
2084 /* Now emit a definition of the label the cases branch to, if any. */
2091 }
2092 \f
2093 /* Return true if VAL (of type TYPE) can equal the minimum value if MAX is
2094 false, or the maximum value if MAX is true, of TYPE. */
2096 static bool
2098 {
2105 val = (max
2113 }
2115 /* Return true if VAL (of type TYPE) can equal the minimum value of TYPE.
2116 If REVERSE is true, minimum value is taken as maximum value. */
2120 {
2122 }
2124 /* Return true if VAL (of type TYPE) can equal the maximum value of TYPE.
2125 If REVERSE is true, maximum value is taken as minimum value. */
2129 {
2131 }
2133 /* Return true if VAL1 can be lower than VAL2. */
2135 static bool
2137 {
2151 }
2153 /* Subroutine of gnat_to_gnu to translate gnat_node, an N_Loop_Statement,
2154 to a GCC tree, which is returned. */
2156 static tree
2158 {
2164 tree gnu_result;
2166 /* Set location information for statement and end label. */
2172 /* Save the end label of this LOOP_STMT in a stack so that a corresponding
2173 N_Exit_Statement can find it. */
2176 /* Set the condition under which the loop must keep going.
2177 For the case "LOOP .... END LOOP;" the condition is always true. */
2179 ;
2181 /* For the case "WHILE condition LOOP ..... END LOOP;" it's immediate. */
2186 /* Otherwise we have an iteration scheme and the condition is given by the
2187 bounds of the subtype of the iteration variable. */
2188 else
2189 {
2202 /* We must disable modulo reduction for the iteration variable, if any,
2203 in order for the loop comparison to be effective. */
2205 {
2211 }
2212 else
2213 {
2219 }
2221 /* We use two different strategies to translate the loop, depending on
2222 whether optimization is enabled.
2224 If it is, we try to generate the canonical form of loop expected by
2225 the loop optimizer, which is the do-while form:
2227 ENTRY_COND
2228 loop:
2229 TOP_UPDATE
2230 BODY
2231 BOTTOM_COND
2232 GOTO loop
2234 This makes it possible to bypass loop header copying and to turn the
2235 BOTTOM_COND into an inequality test. This should catch (almost) all
2236 loops with constant starting point. If we cannot, we try to generate
2237 the default form, which is:
2239 loop:
2240 TOP_COND
2241 BODY
2242 BOTTOM_UPDATE
2243 GOTO loop
2245 It will be rotated during loop header copying and an entry test added
2246 to yield the do-while form. This should catch (almost) all loops with
2247 constant ending point. If we cannot, we generate the fallback form:
2249 ENTRY_COND
2250 loop:
2251 BODY
2252 BOTTOM_COND
2253 BOTTOM_UPDATE
2254 GOTO loop
2256 which works in all cases but for which loop header copying will copy
2257 the BOTTOM_COND, thus adding a third conditional branch.
2259 If optimization is disabled, loop header copying doesn't come into
2260 play and we try to generate the loop forms with the less conditional
2261 branches directly. First, the default form, it should catch (almost)
2262 all loops with constant ending point. Then, if we cannot, we try to
2263 generate the shifted form:
2265 loop:
2266 TOP_COND
2267 TOP_UPDATE
2268 BODY
2269 GOTO loop
2271 which should catch loops with constant starting point. Otherwise, if
2272 we cannot, we generate the fallback form. */
2275 {
2276 /* We can use the do-while form if GNU_FIRST-1 doesn't overflow. */
2278 {
2283 }
2285 /* Otherwise, we can use the default form if GNU_LAST+1 doesn't. */
2287 ;
2289 /* Otherwise, use the fallback form. */
2290 else
2292 }
2293 else
2294 {
2295 /* We can use the default form if GNU_LAST+1 doesn't overflow. */
2297 ;
2299 /* Otherwise, we can use the shifted form if neither GNU_FIRST-1 nor
2300 GNU_LAST-1 does. */
2303 {
2309 }
2311 /* Otherwise, use the fallback form. */
2312 else
2314 }
2319 /* If we use the BOTTOM_COND, we can turn the test into an inequality
2320 test but we may have to add ENTRY_COND to protect the empty loop. */
2322 {
2325 {
2326 gnu_cond_expr
2332 }
2333 }
2335 /* Open a new nesting level that will surround the loop to declare the
2336 iteration variable. */
2340 /* Declare the iteration variable and set it to its initial value. */
2345 /* Do all the arithmetics in the base type. */
2348 /* Set either the top or bottom exit condition. */
2351 gnu_last);
2353 /* Set either the top or bottom update statement and give it the source
2354 location of the iteration for better coverage info. */
2360 gnat_iter_scheme);
2361 }
2363 /* If the loop was named, have the name point to this loop. In this case,
2364 the association is not a DECL node, but the end label of the loop. */
2368 /* Make the loop body into its own block, so any allocated storage will be
2369 released every iteration. This is needed for stack allocation. */
2374 /* If we declared a variable, then we are in a statement group for that
2375 declaration. Add the LOOP_STMT to it and make that the "loop". */
2377 {
2381 }
2383 /* If we have an outer COND_EXPR, that's our result and this loop is its
2384 "true" statement. Otherwise, the result is the LOOP_STMT. */
2386 {
2390 }
2391 else
2397 }
2398 \f
2399 /* Emit statements to establish __gnat_handle_vms_condition as a VMS condition
2400 handler for the current function. */
2402 /* This is implemented by issuing a call to the appropriate VMS specific
2403 builtin. To avoid having VMS specific sections in the global gigi decls
2404 array, we maintain the decls of interest here. We can't declare them
2405 inside the function because we must mark them never to be GC'd, which we
2406 can only do at the global level. */
2411 static void
2413 {
2414 tree establish_stmt;
2416 /* Elaborate the required decls on the first call. Check on the decl for
2417 the gnat condition handler to decide, as this is one we create so we are
2418 sure that it will be non null on subsequent calls. The builtin decl is
2419 looked up so remains null on targets where it is not implemented yet. */
2421 {
2422 vms_builtin_establish_handler_decl
2423 = builtin_decl_for
2426 gnat_vms_condition_handler_decl
2428 NULL_TREE,
2430 ptr_void_type_node,
2431 ptr_void_type_node,
2432 NULL_TREE),
2435 /* ??? DECL_CONTEXT shouldn't have been set because of DECL_EXTERNAL. */
2437 }
2439 /* Do nothing if the establish builtin is not available, which might happen
2440 on targets where the facility is not implemented. */
2444 establish_stmt
2446 build_unary_op
2448 gnat_vms_condition_handler_decl));
2451 }
2452 \f
2453 /* Subroutine of gnat_to_gnu to process gnat_node, an N_Subprogram_Body. We
2454 don't return anything. */
2456 static void
2458 {
2459 /* Defining identifier of a parameter to the subprogram. */
2460 Entity_Id gnat_param;
2461 /* The defining identifier for the subprogram body. Note that if a
2462 specification has appeared before for this body, then the identifier
2463 occurring in that specification will also be a defining identifier and all
2464 the calls to this subprogram will point to that specification. */
2465 Entity_Id gnat_subprog_id
2468 /* The FUNCTION_DECL node corresponding to the subprogram spec. */
2469 tree gnu_subprog_decl;
2470 /* Its RESULT_DECL node. */
2471 tree gnu_result_decl;
2472 /* Its FUNCTION_TYPE node. */
2473 tree gnu_subprog_type;
2474 /* The TYPE_CI_CO_LIST of its FUNCTION_TYPE node, if any. */
2475 tree gnu_cico_list;
2476 /* The entry in the CI_CO_LIST that represents a function return, if any. */
2478 tree gnu_result;
2481 /* If this is a generic object or if it has been eliminated,
2482 ignore it. */
2488 /* If this subprogram acts as its own spec, define it. Otherwise, just get
2489 the already-elaborated tree node. However, if this subprogram had its
2490 elaboration deferred, we will already have made a tree node for it. So
2491 treat it as not being defined in that case. Such a subprogram cannot
2492 have an address clause or a freeze node, so this test is safe, though it
2493 does disable some otherwise-useful error checking. */
2494 gnu_subprog_decl
2504 /* If the function returns by invisible reference, make it explicit in the
2505 function body. See gnat_to_gnu_entity, E_Subprogram_Type case.
2506 Handle the explicit case here and the copy-in/copy-out case below. */
2508 {
2512 }
2514 /* Propagate the debug mode. */
2518 /* Set the line number in the decl to correspond to that of the body so that
2519 the line number notes are written correctly. */
2522 /* Initialize the information structure for the function. */
2530 /* If there are In Out or Out parameters, we need to ensure that the return
2531 statement properly copies them out. We do this by making a new block and
2532 converting any return into a goto to a label at the end of the block. */
2534 {
2543 /* If this is a function with In Out or Out parameters, we also need a
2544 variable for the return value to be placed. */
2546 {
2547 tree gnu_return_type
2550 /* If the function returns by invisible reference, make it
2551 explicit in the function body. See gnat_to_gnu_entity,
2552 E_Subprogram_Type case. */
2556 gnu_return_var
2561 }
2565 /* See whether there are parameters for which we don't have a GCC tree
2566 yet. These must be Out parameters. Make a VAR_DECL for them and
2567 put it into TYPE_CI_CO_LIST, which must contain an empty entry too.
2568 We can match up the entries because TYPE_CI_CO_LIST is in the order
2569 of the parameters. */
2574 {
2577 /* Skip any entries that have been already filled in; they must
2578 correspond to In Out parameters. */
2582 /* Do any needed references for padded types. */
2586 }
2587 }
2588 else
2591 /* Get a tree corresponding to the code for the subprogram. */
2595 /* On VMS, establish our condition handler to possibly turn a condition into
2596 the corresponding exception if the subprogram has a foreign convention or
2597 is exported.
2599 To ensure proper execution of local finalizations on condition instances,
2600 we must turn a condition into the corresponding exception even if there
2601 is no applicable Ada handler, and need at least one condition handler per
2602 possible call chain involving GNAT code. OTOH, establishing the handler
2603 has a cost so we want to minimize the number of subprograms into which
2604 this happens. The foreign or exported condition is expected to satisfy
2605 all the constraints. */
2613 /* Generate the code of the subprogram itself. A return statement will be
2614 present and any Out parameters will be handled there. */
2619 /* If we are dealing with a return from an Ada procedure with parameters
2620 passed by copy-in/copy-out, we need to return a record containing the
2621 final values of these parameters. If the list contains only one entry,
2622 return just that entry though.
2624 For a full description of the copy-in/copy-out parameter mechanism, see
2625 the part of the gnat_to_gnu_entity routine dealing with the translation
2626 of subprograms.
2628 We need to make a block that contains the definition of that label and
2629 the copying of the return value. It first contains the function, then
2630 the label and copy statement. */
2632 {
2633 tree gnu_retval;
2641 else
2643 gnu_cico_list);
2649 }
2653 /* If we populated the parameter attributes cache, we need to make sure that
2654 the cached expressions are evaluated on all the possible paths leading to
2655 their uses. So we force their evaluation on entry of the function. */
2658 {
2665 {
2672 }
2676 }
2678 /* Set the end location. */
2679 Sloc_to_locus
2687 /* Finally annotate the parameters and disconnect the trees for parameters
2688 that we have turned into variables since they are now unusable. */
2692 {
2702 }
2711 }
2712 \f
2714 /* Create a temporary variable with PREFIX and initialize it with GNU_INIT.
2715 Put the initialization statement into GNU_INIT_STMT and annotate it with
2716 the SLOC of GNAT_NODE. Return the temporary variable. */
2718 static tree
2720 Node_Id gnat_node)
2721 {
2732 }
2734 /* Subroutine of gnat_to_gnu to translate gnat_node, either an N_Function_Call
2735 or an N_Procedure_Call_Statement, to a GCC tree, which is returned.
2736 GNU_RESULT_TYPE_P is a pointer to where we should place the result type.
2737 If GNU_TARGET is non-null, this must be a function call on the RHS of a
2738 N_Assignment_Statement and the result is to be placed into that object. */
2740 static tree
2742 {
2743 /* The GCC node corresponding to the GNAT subprogram name. This can either
2744 be a FUNCTION_DECL node if we are dealing with a standard subprogram call,
2745 or an indirect reference expression (an INDIRECT_REF node) pointing to a
2746 subprogram. */
2748 /* The FUNCTION_TYPE node giving the GCC type of the subprogram. */
2751 Entity_Id gnat_formal;
2752 Node_Id gnat_actual;
2764 /* If we are calling a stubbed function, raise Program_Error, but Elaborate
2765 all our args first. */
2767 {
2777 {
2780 }
2783 }
2785 /* The only way we can be making a call via an access type is if Name is an
2786 explicit dereference. In that case, get the list of formal args from the
2787 type the access type is pointing to. Otherwise, get the formals from the
2788 entity being called. */
2792 /* Assume here that this must be 'Elab_Body or 'Elab_Spec. */
2794 else
2797 /* If we are translating a statement, push a new binding level that will
2798 surround it to declare the temporaries created for the call. Likewise
2799 if we'll be returning a value and also have copy-in/copy-out parameters,
2800 as we need to create statements to fetch their value after the call.
2802 ??? We could do that unconditionally, but the middle-end doesn't seem
2803 to be prepared to handle the construct in nested contexts. */
2805 {
2809 }
2811 /* The lifetime of the temporaries created for the call ends with the call
2812 so we can give them the scope of the elaboration routine at top level. */
2814 {
2817 }
2819 /* Create the list of the actual parameters as GCC expects it, namely a
2820 chain of TREE_LIST nodes in which the TREE_VALUE field of each node
2821 is an expression and the TREE_PURPOSE field is null. But skip Out
2822 parameters not passed by reference and that need not be copied in. */
2827 {
2831 /* In the Out or In Out case, we must suppress conversions that yield
2832 an lvalue but can nevertheless cause the creation of a temporary,
2833 because we need the real object in this case, either to pass its
2834 address if it's passed by reference or as target of the back copy
2835 done after the call if it uses the copy-in copy-out mechanism.
2836 We do it in the In case too, except for an unchecked conversion
2837 because it alone can cause the actual to be misaligned and the
2838 addressability test is applied to the real object. */
2839 bool suppress_type_conversion
2844 Node_Id gnat_name = suppress_type_conversion
2847 tree gnu_actual;
2849 /* If it's possible we may need to use this expression twice, make sure
2850 that any side-effects are handled via SAVE_EXPRs; likewise if we need
2851 to force side-effects before the call.
2852 ??? This is more conservative than we need since we don't need to do
2853 this for pass-by-ref with no conversion. */
2857 /* If we are passing a non-addressable parameter by reference, pass the
2858 address of a copy. In the Out or In Out case, set up to copy back
2859 out after the call. */
2867 {
2871 /* Do not issue warnings for CONSTRUCTORs since this is not a copy
2872 but sort of an instantiation for them. */
2874 ;
2876 /* If the type is passed by reference, a copy is not allowed. */
2879 gnat_actual);
2881 /* For users of Starlet we issue a warning because the interface
2882 apparently assumes that by-ref parameters outlive the procedure
2883 invocation. The code still will not work as intended, but we
2884 cannot do much better since low-level parts of the back-end
2885 would allocate temporaries at will because of the misalignment
2886 if we did not do so here. */
2888 {
2889 post_error
2891 post_error_ne
2895 gnat_formal);
2896 }
2898 /* If the actual type of the object is already the nominal type,
2899 we have nothing to do, except if the size is self-referential
2900 in which case we'll remove the unpadding below. */
2903 ;
2905 /* Otherwise remove the unpadding from all the objects. */
2907 && TYPE_IS_PADDING_P
2911 /* Otherwise convert to the nominal type of the object if needed.
2912 There are several cases in which we need to make the temporary
2913 using this type instead of the actual type of the object when
2914 they are distinct, because the expectations of the callee would
2915 otherwise not be met:
2916 - if it's a justified modular type,
2917 - if the actual type is a smaller form of it,
2918 - if it's a smaller form of the actual type. */
2922 gnu_name_type)))
2928 /* If we haven't pushed a binding level and this is an In Out or Out
2929 parameter, push a new one. This is needed to wrap the copy-back
2930 statements we'll be making below. */
2932 {
2936 }
2938 /* Create an explicit temporary holding the copy. This ensures that
2939 its lifetime is as narrow as possible around a statement. */
2940 gnu_temp
2943 /* But initialize it on the fly like for an implicit temporary as
2944 we aren't necessarily dealing with a statement. */
2946 gnu_temp);
2948 /* Set up to move the copy back to the original if needed. */
2950 {
2952 gnu_temp);
2955 }
2956 }
2958 /* Start from the real object and build the actual. */
2961 /* If this was a procedure call, we may not have removed any padding.
2962 So do it here for the part we will use as an input, if any. */
2965 gnu_actual
2968 /* Put back the conversion we suppressed above in the computation of the
2969 real object. And even if we didn't suppress any conversion there, we
2970 may have suppressed a conversion to the Etype of the actual earlier,
2971 since the parent is a procedure call, so put it back here. */
2974 gnu_actual
2977 else
2978 gnu_actual
2981 /* Make sure that the actual is in range of the formal's type. */
2984 gnu_actual
2987 /* Unless this is an In parameter, we must remove any justified modular
2988 building from GNU_NAME to get an lvalue. */
2993 gnu_name
2996 /* If we have not saved a GCC object for the formal, it means it is an
2997 Out parameter not passed by reference and that need not be copied in.
2998 Otherwise, first see if the parameter is passed by reference. */
3002 {
3004 {
3005 /* In Out or Out parameters passed by reference don't use the
3006 copy-in copy-out mechanism so the address of the real object
3007 must be passed to the function. */
3010 /* If we have a padded type, be sure we've removed padding. */
3013 gnu_actual);
3015 /* If we have the constructed subtype of an aliased object
3016 with an unconstrained nominal subtype, the type of the
3017 actual includes the template, although it is formally
3018 constrained. So we need to convert it back to the real
3019 constructed subtype to retrieve the constrained part
3020 and takes its address. */
3026 gnu_actual);
3027 }
3029 /* There is no need to convert the actual to the formal's type before
3030 taking its address. The only exception is for unconstrained array
3031 types because of the way we build fat pointers. */
3035 /* The symmetry of the paths to the type of an entity is broken here
3036 since arguments don't know that they will be passed by ref. */
3040 gnu_actual
3042 gnu_actual);
3045 }
3049 {
3055 {
3058 }
3060 /* Take the address of the object and convert to the proper pointer
3061 type. We'd like to actually compute the address of the beginning
3062 of the array using an ADDR_EXPR of an ARRAY_REF, but there's a
3063 possibility that the ARRAY_REF might return a constant and we'd be
3064 getting the wrong address. Neither approach is exactly correct,
3065 but this is the most likely to work in all cases. */
3067 }
3071 {
3074 /* If this is 'Null_Parameter, pass a zero descriptor. */
3078 gnu_actual
3080 else
3083 gnat_formal,
3084 gnat_actual));
3085 }
3086 else
3087 {
3088 tree gnu_size;
3094 {
3095 /* Make sure side-effects are evaluated before the call. */
3099 }
3103 /* If this is 'Null_Parameter, pass a zero even though we are
3104 dereferencing it. */
3110 gnu_actual
3114 integer_zero_node),
3116 else
3118 }
3121 }
3124 gnu_actual_vec);
3127 /* If this is a subprogram with copy-in/copy-out parameters, we need to
3128 unpack the valued returned from the function into the In Out or Out
3129 parameters. We deal with the function return (if this is an Ada
3130 function) below. */
3132 {
3133 /* List of FIELD_DECLs associated with the PARM_DECLs of the copy-in/
3134 copy-out parameters. */
3138 /* The call sequence must contain one and only one call, even though the
3139 function is pure. Save the result into a temporary if needed. */
3141 {
3142 tree gnu_stmt;
3143 gnu_call
3148 }
3150 /* The first entry is for the actual return value if this is a
3151 function, so skip it. */
3157 else
3164 /* If we are dealing with a copy-in/copy-out parameter, we must
3165 retrieve its value from the record returned in the call. */
3171 || (DECL_BY_DESCRIPTOR_P
3174 {
3175 /* Get the value to assign to this Out or In Out parameter. It is
3176 either the result of the function if there is only a single such
3177 parameter or the appropriate field from the record returned. */
3178 tree gnu_result
3180 ? gnu_call
3184 /* If the actual is a conversion, get the inner expression, which
3185 will be the real destination, and convert the result to the
3186 type of the actual parameter. */
3187 tree gnu_actual
3190 /* If the result is a padded type, remove the padding. */
3192 gnu_result
3194 gnu_result);
3196 /* If the actual is a type conversion, the real target object is
3197 denoted by the inner Expression and we need to convert the
3198 result to the associated type.
3199 We also need to convert our gnu assignment target to this type
3200 if the corresponding GNU_NAME was constructed from the GNAT
3201 conversion node and not from the inner Expression. */
3203 {
3204 gnu_result
3205 = convert_with_check
3213 }
3215 /* Unchecked conversions as actuals for Out parameters are not
3216 allowed in user code because they are not variables, but do
3217 occur in front-end expansions. The associated GNU_NAME is
3218 always obtained from the inner expression in such cases. */
3221 gnu_result,
3223 else
3224 {
3226 gnu_result
3228 gnat_actual);
3233 }
3241 }
3242 }
3244 /* If this is a function call, the result is the call expression unless a
3245 target is specified, in which case we copy the result into the target
3246 and return the assignment statement. */
3248 {
3251 /* If this is a function with copy-in/copy-out parameters, extract the
3252 return value from it and update the return type. */
3254 {
3260 }
3262 /* If the function returns an unconstrained array or by direct reference,
3263 we have to dereference the pointer. */
3269 {
3273 /* If range check is needed, emit code to generate it. */
3275 gnu_call
3277 gnat_parent);
3279 /* ??? If the return type has non-constant size, then force the
3280 return slot optimization as we would not be able to generate
3281 a temporary. Likewise if it was unconstrained as we would
3282 copy too much data. That's what has been done historically. */
3285 && CONTAINS_PLACEHOLDER_P
3288 else
3291 gnu_call
3295 }
3296 else
3298 }
3300 /* Otherwise, if this is a procedure call statement without copy-in/copy-out
3301 parameters, the result is just the call statement. */
3308 /* If we have pushed a binding level, the result is the statement group.
3309 Otherwise it's just the call expression. */
3311 {
3312 /* If we need a value and haven't created the call statement, do so. */
3314 {
3315 tree gnu_stmt;
3316 gnu_call
3319 }
3324 }
3325 else
3328 /* If we need a value, make a COMPOUND_EXPR to return it; otherwise,
3329 return the result. Deal specially with UNCONSTRAINED_ARRAY_REF. */
3332 gnu_call);
3335 }
3336 \f
3337 /* Subroutine of gnat_to_gnu to translate gnat_node, an
3338 N_Handled_Sequence_Of_Statements, to a GCC tree, which is returned. */
3340 static tree
3342 {
3345 /* If just annotating, ignore all EH and cleanups. */
3349 bool setjmp_longjmp
3355 tree gnu_result;
3356 tree gnu_expr;
3357 Node_Id gnat_temp;
3359 /* The GCC exception handling mechanism can handle both ZCX and SJLJ schemes
3360 and we have our own SJLJ mechanism. To call the GCC mechanism, we call
3361 add_cleanup, and when we leave the binding, end_stmt_group will create
3362 the TRY_FINALLY_EXPR.
3364 ??? The region level calls down there have been specifically put in place
3365 for a ZCX context and currently the order in which things are emitted
3366 (region/handlers) is different from the SJLJ case. Instead of putting
3367 other calls with different conditions at other places for the SJLJ case,
3368 it seems cleaner to reorder things for the SJLJ case and generalize the
3369 condition to make it not ZCX specific.
3371 If there are any exceptions or cleanup processing involved, we need an
3372 outer statement group (for Setjmp_Longjmp) and binding level. */
3374 {
3377 }
3379 /* If using setjmp_longjmp, make the variables for the setjmp buffer and save
3380 area for address of previous buffer. Do this first since we need to have
3381 the setjmp buf known for any decls in this block. */
3383 {
3391 /* The __builtin_setjmp receivers will immediately reinstall it. Now
3392 because of the unstructured form of EH used by setjmp_longjmp, there
3393 might be forward edges going to __builtin_setjmp receivers on which
3394 it is uninitialized, although they will never be actually taken. */
3404 /* When we exit this block, restore the saved value. */
3407 }
3409 /* If we are to call a function when exiting this block, add a cleanup
3410 to the binding level we made above. Note that add_cleanup is FIFO
3411 so we must register this cleanup after the EH cleanup just above. */
3416 /* Now build the tree for the declarations and statements inside this block.
3417 If this is SJLJ, set our jmp_buf as the current buffer. */
3423 gnu_jmpbuf_decl)));
3429 /* Generate code for each statement in the block. */
3437 /* Now generate code for the two exception models, if either is relevant for
3438 this block. */
3440 {
3442 tree gnu_handler;
3444 /* Make a binding level for the exception handling declarations and code
3445 and set up gnu_except_ptr_stack for the handlers to use. */
3456 /* Generate code for each handler. The N_Exception_Handler case does the
3457 real work and returns a COND_EXPR for each handler, which we chain
3458 together here. */
3461 {
3464 /* If this is the first one, set it as the outer one. Otherwise,
3465 point the "else" part of the previous handler to us. Then point
3466 to our "else" part. */
3469 else
3473 }
3475 /* If none of the exception handlers did anything, re-raise but do not
3476 defer abortion. */
3479 set_expr_location_from_node
3485 else
3488 /* End the binding level dedicated to the exception handlers and get the
3489 whole statement group. */
3494 /* If the setjmp returns 1, we restore our incoming longjmp value and
3495 then check the handlers. */
3498 gnu_jmpsave_decl),
3499 gnat_node);
3503 /* This block is now "if (setjmp) ... <handlers> else <block>". */
3505 (build_call_1_expr
3508 gnu_jmpbuf_decl))),
3510 }
3512 {
3513 tree gnu_handlers;
3515 /* First make a block containing the handlers. */
3523 /* Now make the TRY_CATCH_EXPR for the block. */
3526 }
3527 else
3530 /* Now close our outer block, if we had to make one. */
3532 {
3536 }
3539 }
3540 \f
3541 /* Subroutine of gnat_to_gnu to translate gnat_node, an N_Exception_Handler,
3542 to a GCC tree, which is returned. This is the variant for Setjmp_Longjmp
3543 exception handling. */
3545 static tree
3547 {
3548 /* Unless this is "Others" or the special "Non-Ada" exception for Ada, make
3549 an "if" statement to select the proper exceptions. For "Others", exclude
3550 exceptions where Handled_By_Others is nonzero unless the All_Others flag
3551 is set. For "Non-ada", accept an exception if "Lang" is 'V'. */
3554 Node_Id gnat_temp;
3558 {
3559 tree this_choice;
3562 {
3565 else
3566 this_choice
3567 = build_binary_op
3569 convert
3571 build_component_ref
3572 (build_unary_op
3577 integer_zero_node);
3578 }
3582 {
3584 tree gnu_expr;
3586 /* Exception may be a renaming. Recover original exception which is
3587 the one elaborated and registered. */
3593 this_choice
3594 = build_binary_op
3600 /* If this is the distinguished exception "Non_Ada_Error" (and we are
3601 in VMS mode), also allow a non-Ada exception (a VMS condition) t
3602 match. */
3604 {
3605 tree gnu_comp
3606 = build_component_ref
3611 this_choice
3612 = build_binary_op
3616 this_choice);
3617 }
3618 }
3619 else
3624 }
3627 }
3628 \f
3629 /* Subroutine of gnat_to_gnu to translate gnat_node, an N_Exception_Handler,
3630 to a GCC tree, which is returned. This is the variant for ZCX. */
3632 static tree
3634 {
3636 tree gnu_expr;
3637 tree gnu_etype;
3638 tree gnu_current_exc_ptr;
3639 tree gnu_incoming_exc_ptr;
3640 Node_Id gnat_temp;
3642 /* We build a TREE_LIST of nodes representing what exception types this
3643 handler can catch, with special cases for others and all others cases.
3645 Each exception type is actually identified by a pointer to the exception
3646 id, or to a dummy object for "others" and "all others". */
3649 {
3651 {
3652 tree gnu_expr
3655 gnu_etype
3657 }
3660 {
3663 /* Exception may be a renaming. Recover original exception which is
3664 the one elaborated and registered. */
3671 /* The Non_Ada_Error case for VMS exceptions is handled
3672 by the personality routine. */
3673 }
3674 else
3677 /* The GCC interface expects NULL to be passed for catch all handlers, so
3678 it would be quite tempting to set gnu_etypes_list to NULL if gnu_etype
3679 is integer_zero_node. It would not work, however, because GCC's
3680 notion of "catch all" is stronger than our notion of "others". Until
3681 we correctly use the cleanup interface as well, doing that would
3682 prevent the "all others" handlers from being seen, because nothing
3683 can be caught beyond a catch all from GCC's point of view. */
3685 }
3690 /* Expand a call to the begin_handler hook at the beginning of the handler,
3691 and arrange for a call to the end_handler hook to occur on every possible
3692 exit path.
3694 The hooks expect a pointer to the low level occurrence. This is required
3695 for our stack management scheme because a raise inside the handler pushes
3696 a new occurrence on top of the stack, which means that this top does not
3697 necessarily match the occurrence this handler was dealing with.
3699 __builtin_eh_pointer references the exception occurrence being
3700 propagated. Upon handler entry, this is the exception for which the
3701 handler is triggered. This might not be the case upon handler exit,
3702 however, as we might have a new occurrence propagated by the handler's
3703 body, and the end_handler hook called as a cleanup in this context.
3705 We use a local variable to retrieve the incoming value at handler entry
3706 time, and reuse it to feed the end_handler hook's argument at exit. */
3708 gnu_current_exc_ptr
3717 gnu_incoming_exc_ptr),
3718 gnat_node);
3719 /* ??? We don't seem to have an End_Label at hand to set the location. */
3721 Empty);
3727 }
3728 \f
3729 /* Subroutine of gnat_to_gnu to generate code for an N_Compilation unit. */
3731 static void
3733 {
3738 /* Make the decl for the elaboration procedure. */
3739 tree gnu_elab_proc_decl
3740 = create_subprog_decl
3748 /* Initialize the information structure for the function. */
3757 /* For a body, first process the spec if there is one. */
3761 {
3764 }
3766 /* If we can inline, generate code for all the inlined subprograms. */
3768 {
3769 Entity_Id gnat_entity;
3774 {
3778 {
3779 /* ??? This really should always be present. */
3782 gnat_body
3784 }
3787 {
3788 /* Define the entity first so we set DECL_EXTERNAL. */
3791 }
3792 }
3793 }
3796 {
3803 }
3809 /* Process any pragmas and actions following the unit. */
3814 /* Save away what we've made so far and record this potential elaboration
3815 procedure. */
3821 Sloc_to_locus
3830 /* Generate elaboration code for this unit, if necessary, and say whether
3831 we did or not. */
3834 /* Invalidate the global renaming pointers. This is necessary because
3835 stabilization of the renamed entities may create SAVE_EXPRs which
3836 have been tied to a specific elaboration routine just above. */
3838 }
3839 \f
3840 /* Return true if GNAT_NODE, an unchecked type conversion, is a no-op as far
3841 as gigi is concerned. This is used to avoid conversions on the LHS. */
3843 static bool
3845 {
3848 /* The conversion must be on the LHS of an assignment or an actual parameter
3849 of a call. Otherwise, even if the conversion was essentially a no-op, it
3850 could de facto ensure type consistency and this should be preserved. */
3860 /* We're interested in artificial conversions generated by the front-end
3861 to make private types explicit, e.g. in Expand_Assign_Array. */
3868 /* The direct conversion to the underlying type is a no-op. */
3872 /* For an array subtype, the conversion to the PAT is a no-op. */
3877 /* For a record subtype, the conversion to the type is a no-op. */
3883 }
3885 /* This function is the driver of the GNAT to GCC tree transformation process.
3886 It is the entry point of the tree transformer. GNAT_NODE is the root of
3887 some GNAT tree. Return the root of the corresponding GCC tree. If this
3888 is an expression, return the GCC equivalent of the expression. If this
3889 is a statement, return the statement or add it to the current statement
3890 group, in which case anything returned is to be interpreted as occurring
3891 after anything added. */
3893 tree
3895 {
3901 Node_Id gnat_temp;
3903 /* Save node number for error message and set location information. */
3907 /* If this node is a statement and we are only annotating types, return an
3908 empty statement list. */
3912 /* If this node is a non-static subexpression and we are only annotating
3913 types, make this into a NULL_EXPR. */
3920 N_Raise_Constraint_Error));
3929 {
3932 /* If this is a statement and we are at top level, it must be part of
3933 the elaboration procedure, so mark us as being in that procedure. */
3935 {
3938 }
3940 /* If we are in the elaboration procedure, check if we are violating a
3941 No_Elaboration_Code restriction by having a statement there. Don't
3942 check for a possible No_Elaboration_Code restriction violation on
3943 N_Handled_Sequence_Of_Statements, as we want to signal an error on
3944 every nested real statement instead. This also avoids triggering
3945 spurious errors on dummy (empty) sequences created by the front-end
3946 for package bodies in some cases. */
3950 }
3953 {
3954 /********************************/
3955 /* Chapter 2: Lexical Elements */
3956 /********************************/
3966 {
3967 tree gnu_type;
3969 /* Get the type of the result, looking inside any padding and
3970 justified modular types. Then get the value in that type. */
3979 /* If the result overflows (meaning it doesn't fit in its base type),
3980 abort. We would like to check that the value is within the range
3981 of the subtype, but that causes problems with subtypes whose usage
3982 will raise Constraint_Error and with biased representation, so
3983 we don't. */
3985 }
3989 /* If a Entity is present, it means that this was one of the
3990 literals in a user-defined character type. In that case,
3991 just return the value in the CONST_DECL. Otherwise, use the
3992 character code. In that case, the base type should be an
3993 INTEGER_TYPE, but we won't bother checking for that. */
3997 else
3998 gnu_result
3999 = build_int_cst_type
4004 /* If this is of a fixed-point type, the value we want is the
4005 value of the corresponding integer. */
4007 {
4010 gnu_result_type);
4012 }
4014 /* We should never see a Vax_Float type literal, since the front end
4015 is supposed to transform these using appropriate conversions. */
4019 else
4020 {
4025 /* If the real value is zero, so is the result. Otherwise,
4026 convert it to a machine number if it isn't already. That
4027 forces BASE to 0 or 2 and simplifies the rest of our logic. */
4030 else
4031 {
4033 ur_realval
4037 gnu_result
4040 /* If we have a base of zero, divide by the denominator.
4041 Otherwise, the base must be 2 and we scale the value, which
4042 we know can fit in the mantissa of the type (hence the use
4043 of that type above). */
4045 gnu_result
4048 gnu_result,
4050 gnu_result_type));
4051 else
4052 {
4053 REAL_VALUE_TYPE tmp;
4059 }
4060 }
4062 /* Now see if we need to negate the result. Do it this way to
4063 properly handle -0. */
4065 gnu_result
4067 gnu_result);
4068 }
4075 {
4082 else
4085 /* Build the string with the characters in the literal. Note
4086 that Ada strings are 1-origin. */
4090 /* Put a null at the end of the string in case it's in a context
4091 where GCC will want to treat it as a C string. */
4096 /* Strings in GCC don't normally have types, but we want
4097 this to not be converted to the array type. */
4102 }
4103 else
4104 {
4105 /* Build a list consisting of each character, then make
4106 the aggregate. */
4115 {
4122 }
4125 }
4132 /**************************************/
4133 /* Chapter 3: Declarations and Types */
4134 /**************************************/
4151 /* If we are just annotating types and this object has an unconstrained
4152 or task type, don't elaborate it. */
4162 && (!type_annotate_only
4164 {
4167 gnu_expr
4170 /* If this object has its elaboration delayed, we must force
4171 evaluation of GNU_EXPR right now and save it for when the object
4172 is frozen. */
4174 {
4176 ;
4178 gnu_expr
4183 else
4187 }
4188 }
4189 else
4195 /* If this is a deferred constant with an address clause, we ignore the
4196 full view since the clause is on the partial view and we cannot have
4197 2 different GCC trees for the object. The only bits of the full view
4198 we will use is the initializer, but it will be directly fetched. */
4211 /* Don't do anything if this renaming is handled by the front end or if
4212 we are just annotating types and this object has a composite or task
4213 type, don't elaborate it. We return the result in case it has any
4214 SAVE_EXPRs in it that need to be evaluated here. */
4216 && ! (type_annotate_only
4220 gnu_result
4223 else
4236 /* These are fully handled in the front end. */
4240 /*************************************/
4241 /* Chapter 4: Names and Expressions */
4242 /*************************************/
4251 {
4253 tree gnu_type;
4260 /* Convert vector inputs to their representative array type, to fit
4261 what the code below expects. */
4266 /* If we got a padded type, remove it too. */
4268 gnu_array_object
4270 gnu_array_object);
4274 /* First compute the number of dimensions of the array, then
4275 fill the expression array, the order depending on whether
4276 this is a Convention_Fortran array or not. */
4281 ;
4290 else
4298 {
4304 gnu_expr
4305 = emit_index_check
4309 gnat_temp);
4313 }
4314 }
4320 {
4322 tree gnu_type;
4327 /* Do any implicit dereferences of the prefix and do any needed
4328 range check. */
4333 {
4334 /* Get the bounds of the slice. */
4335 tree gnu_index_type
4339 /* Get the permitted bounds. */
4340 tree gnu_base_index_type
4342 tree gnu_base_min_expr = SUBSTITUTE_PLACEHOLDER_IN_EXPR
4344 tree gnu_base_max_expr = SUBSTITUTE_PLACEHOLDER_IN_EXPR
4351 /* Derive a good type to convert everything to. */
4354 /* Test whether the minimum slice value is too small. */
4357 gnu_min_expr),
4359 gnu_base_min_expr));
4361 /* Test whether the maximum slice value is too large. */
4364 gnu_max_expr),
4366 gnu_base_max_expr));
4368 /* Build a slice index check that returns the low bound,
4369 assuming the slice is not empty. */
4370 gnu_expr = emit_check
4375 /* Build a conditional expression that does the index checks and
4376 returns the low bound if the slice is not empty (max >= min),
4377 and returns the naked low bound otherwise (max < min), unless
4378 it is non-constant and the high bound is; this prevents VRP
4379 from inferring bogus ranges on the unlikely path. */
4383 gnu_max_expr),
4385 gnu_min_expr)),
4386 gnu_expr,
4390 }
4391 else
4392 /* Simply return the naked low bound. */
4395 /* If this is a slice with non-constant size of an array with constant
4396 size, set the maximum size for the allocation of temporaries. */
4403 }
4407 {
4411 tree gnu_field;
4415 {
4420 }
4424 /* For discriminant references in tagged types always substitute the
4425 corresponding discriminant as the actual selected component. */
4430 /* For discriminant references of untagged types always substitute the
4431 corresponding stored discriminant. */
4435 /* Handle extracting the real or imaginary part of a complex.
4436 The real part is the first field and the imaginary the last. */
4441 else
4442 {
4445 /* If there are discriminants, the prefix might be evaluated more
4446 than once, which is a problem if it has side-effects. */
4453 gnu_result
4457 && lvalue_required_for_attribute_p
4459 }
4463 }
4467 {
4468 /* The attribute designator. */
4471 /* The Elab_Spec and Elab_Body attributes are special in that Prefix
4472 is a unit, not an object with a GCC equivalent. */
4474 return
4482 }
4486 /* Like 'Access as far as we are concerned. */
4494 {
4495 tree gnu_aggr_type;
4497 /* ??? It is wrong to evaluate the type now, but there doesn't
4498 seem to be any other practical way of doing it. */
4502 gnu_aggr_type = gnu_result_type
4507 gnu_aggr_type
4517 gnu_result
4520 gnu_aggr_type);
4523 gnu_aggr_type,
4526 gnu_result
4527 = build_binary_op
4532 (Next
4534 else
4538 }
4546 else
4553 /* Get the operand expression. */
4557 gnu_result
4561 kind == N_Type_Conversion
4568 /* Skip further processing if the conversion is deemed a no-op. */
4570 {
4573 }
4577 /* If the result is a pointer type, see if we are improperly
4578 converting to a stricter alignment. */
4581 {
4587 post_error_ne_tree_2
4591 }
4593 /* If we are converting a descriptor to a function pointer, first
4594 build the pointer. */
4606 {
4611 /* GNAT_RANGE is either an N_Range node or an identifier denoting a
4612 subtype. */
4614 {
4617 }
4620 {
4625 }
4626 else
4631 /* If LOW and HIGH are identical, perform an equality test. Otherwise,
4632 ensure that GNU_OBJ is evaluated only once and perform a full range
4633 test. */
4635 gnu_result
4637 else
4638 {
4647 gnu_result
4649 }
4652 gnu_result
4654 }
4662 ? RDIV_EXPR
4669 /* These can either be operations on booleans or on modular types.
4670 Fall through for boolean types since that's the way GNU_CODES is
4671 set up. */
4673 Modular_Integer_Kind))
4674 {
4675 enum tree_code code
4686 }
4688 /* ... fall through ... */
4700 {
4704 tree gnu_type;
4710 /* Pending generic support for efficient vector logical operations in
4711 GCC, convert vectors to their representative array type view and
4712 fallthrough. */
4716 /* If this is a comparison operator, convert any references to
4717 an unconstrained array value into a reference to the
4718 actual array. */
4720 {
4723 }
4725 /* If the result type is a private type, its full view may be a
4726 numeric subtype. The representation we need is that of its base
4727 type, given that it is the result of an arithmetic operation. */
4729 gnu_type = gnu_result_type
4732 /* If this is a shift whose count is not guaranteed to be correct,
4733 we need to adjust the shift count. */
4735 {
4737 tree gnu_max_shift
4744 gnu_rhs
4745 = build_binary_op
4748 gnu_count_type,
4749 gnu_max_shift,
4751 integer_one_node)),
4752 gnu_rhs);
4753 }
4755 /* For right shifts, the type says what kind of shift to do,
4756 so we may need to choose a different type. In this case,
4757 we have to ignore integer overflow lest it propagates all
4758 the way down and causes a CE to be explicitly raised. */
4760 {
4763 }
4766 {
4769 }
4772 {
4778 }
4780 /* Instead of expanding overflow checks for addition, subtraction
4781 and multiplication itself, the front end will leave this to
4782 the back end when Backend_Overflow_Checks_On_Target is set.
4783 As the GCC back end itself does not know yet how to properly
4784 do overflow checking, do it here. The goal is to push
4785 the expansions further into the back end over time. */
4794 else
4795 {
4796 /* Some operations, e.g. comparisons of arrays, generate complex
4797 trees that need to be annotated while they are being built. */
4800 }
4802 /* If this is a logical shift with the shift count not verified,
4803 we must return zero if it is too large. We cannot compensate
4804 above in this case. */
4807 gnu_result
4808 = build_cond_expr
4811 gnu_rhs,
4815 gnu_result);
4816 }
4820 {
4823 tree gnu_false
4827 gnu_result
4829 }
4838 /* This case can apply to a boolean or a modular type.
4839 Fall through for a boolean operand since GNU_CODES is set
4840 up to handle this. */
4844 {
4848 gnu_expr);
4850 }
4852 /* ... fall through ... */
4859 else
4866 gnu_result
4869 else
4875 {
4877 tree gnu_type;
4882 /* The Expression operand can either be an N_Identifier or
4883 Expanded_Name, which must represent a type, or a
4884 N_Qualified_Expression, which contains both the object type and an
4885 initial value for the object. */
4890 {
4891 Entity_Id gnat_desig_type
4899 gnu_init
4904 {
4907 }
4908 else
4909 {
4915 }
4916 }
4917 else
4924 ignore_init_type);
4925 }
4928 /**************************/
4929 /* Chapter 5: Statements */
4930 /**************************/
4938 /* When not optimizing, turn null statements from source into gotos to
4939 the next statement that the middle-end knows how to preserve. */
4941 {
4951 }
4952 else
4957 /* Get the LHS and RHS of the statement and convert any reference to an
4958 unconstrained array into a reference to the underlying array. */
4961 /* If the type has a size that overflows, convert this into raise of
4962 Storage_Error: execution shouldn't have gotten here anyway. */
4966 N_Raise_Storage_Error);
4968 gnu_result
4970 else
4971 {
4972 gnu_rhs
4975 /* If range check is needed, emit code to generate it. */
4978 gnat_node);
4980 gnu_result
4983 /* If the type being assigned is an array type and the two sides are
4984 not completely disjoint, play safe and use memmove. But don't do
4985 it for a bit-packed array as it might not be byte-aligned. */
4990 {
5004 }
5005 }
5009 {
5012 /* Make the outer COND_EXPR. Avoid non-determinism. */
5021 /* Now make a COND_EXPR for each of the "else if" parts. Put each
5022 into the previous "else" part and point to where to put any
5023 outer "else". Also avoid non-determinism. */
5027 {
5037 }
5040 }
5064 gnu_result
5074 {
5077 /* If the subprogram is a function, we must return the expression. */
5079 {
5085 /* If this function has copy-in/copy-out parameters, get the real
5086 variable and type for the return. See Subprogram_to_gnu. */
5088 {
5091 }
5093 /* Do not remove the padding from GNU_RET_VAL if the inner type is
5094 self-referential since we want to allocate the fixed size. */
5096 && TYPE_IS_PADDING_P
5098 && CONTAINS_PLACEHOLDER_P
5102 /* If the subprogram returns by direct reference, return a pointer
5103 to the return value. */
5108 /* Otherwise, if it returns an unconstrained array, we have to
5109 allocate a new version of the result and return it. */
5111 {
5118 }
5120 /* If the subprogram returns by invisible reference, dereference
5121 the pointer it is passed using the type of the return value
5122 and build the copy operation manually. This ensures that we
5123 don't copy too much data, for example if the return type is
5124 unconstrained with a maximum size. */
5126 {
5127 gnu_ret_obj
5129 gnu_result_decl);
5135 }
5137 /* Otherwise, build a regular return. */
5138 else
5140 }
5141 else
5142 {
5145 }
5147 /* If we have a return label defined, convert this into a branch to
5148 that label. The return proper will be handled elsewhere. */
5150 {
5153 gnu_ret_val));
5157 /* When not optimizing, make sure the return is preserved. */
5161 }
5164 }
5172 /***************************/
5173 /* Chapter 6: Subprograms */
5174 /***************************/
5177 /* Unless there is a freeze node, declare the subprogram. We consider
5178 this a "definition" even though we're not generating code for
5179 the subprogram because we will be making the corresponding GCC
5180 node here. */
5189 /* This subprogram doesn't exist for code generation purposes, but we
5190 have to elaborate the types of any parameters and result, unless
5191 they are imported types (nothing to generate in this case).
5193 The parameter list may contain types with freeze nodes, e.g. not null
5194 subtypes, so the subprogram itself may carry a freeze node, in which
5195 case its elaboration must be deferred. */
5197 /* Process the parameter types first. */
5200 = First_Formal_With_Extras
5208 /* Then the result type, set to Standard_Void_Type for procedures. */
5209 {
5210 Entity_Id gnat_temp_type
5215 }
5221 /* For a child unit identifier go up a level to get the specification.
5222 We get this when we try to find the spec of a child unit package
5223 that is the compilation unit being compiled. */
5237 /************************/
5238 /* Chapter 7: Packages */
5239 /************************/
5255 /* If this is the body of a generic package - do nothing. */
5257 {
5260 }
5271 /********************************/
5272 /* Chapter 8: Visibility Rules */
5273 /********************************/
5277 /* Nothing to do here - but these may appear in list of declarations. */
5281 /*********************/
5282 /* Chapter 9: Tasks */
5283 /*********************/
5294 /*********************************************************/
5295 /* Chapter 10: Program Structure and Compilation Issues */
5296 /*********************************************************/
5299 /* This is not called for the main unit on which gigi is invoked. */
5308 /* Simply process whatever unit is being inserted. */
5316 /***************************/
5317 /* Chapter 11: Exceptions */
5318 /***************************/
5321 /* If there is an At_End procedure attached to this node, and the EH
5322 mechanism is SJLJ, we must have at least a corresponding At_End
5323 handler, unless the No_Exception_Handlers restriction is set. */
5338 else
5370 /******************************/
5371 /* Chapter 12: Generic Units */
5372 /******************************/
5382 /* These nodes can appear on a declaration list but there is nothing to
5383 to be done with them. */
5387 /**************************************************/
5388 /* Chapter 13: Representation Clauses and */
5389 /* Implementation-Dependent Features */
5390 /**************************************************/
5395 /* The only one we need to deal with is 'Address since, for the others,
5396 the front-end puts the information elsewhere. */
5400 /* And we only deal with 'Address if the object has a Freeze node. */
5405 /* Get the value to use as the address and save it as the equivalent
5406 for the object. When it is frozen, gnat_to_gnu_entity will do the
5407 right thing. */
5414 /* We do nothing with these. SEM puts the information elsewhere. */
5420 {
5430 /* First retrieve the 3 operand lists built by the front-end. */
5433 {
5440 }
5444 {
5451 }
5455 gnu_clobbers
5458 gnu_clobbers);
5460 /* Then perform some standard checking and processing on the
5461 operands. In particular, mark them addressable if needed. */
5469 {
5471 constraint
5477 {
5478 /* If the operand is going to end up in memory,
5479 mark it addressable. Note that we don't test
5480 allows_mem like in the input case below; this
5481 is modelled on the C front-end. */
5485 }
5486 else
5490 }
5493 {
5495 constraint
5501 {
5502 /* If the operand is going to end up in memory,
5503 mark it addressable. */
5507 }
5508 else
5512 }
5518 }
5519 else
5524 /****************/
5525 /* Added Nodes */
5526 /****************/
5530 /* This construct doesn't define a scope so we don't wrap the statement
5531 list in a BIND_EXPR; however, we wrap it in a SAVE_EXPR to protect it
5532 from unsharing. */
5537 gnu_result
5557 {
5560 tree gnu_obj_type;
5562 tree gnu_obj_size;
5564 /* If this is a thin pointer, we must dereference it to create
5565 a fat pointer, then go back below to a thin pointer. The
5566 reason for this is that we need a fat pointer someplace in
5567 order to properly compute the size. */
5571 gnu_ptr));
5573 /* If this is an unconstrained array, we know the object must
5574 have been allocated with the template in front of the object.
5575 So pass the template address, but get the total size. Do this
5576 by converting to a thin pointer. */
5578 gnu_ptr
5580 (TYPE_OBJECT_RECORD_TYPE
5582 gnu_ptr);
5587 {
5588 gnu_actual_obj_type
5592 gnu_actual_obj_type
5594 gnu_actual_obj_type,
5597 }
5598 else
5605 {
5606 tree gnu_char_ptr_type
5612 }
5614 gnu_result
5618 gnat_node);
5619 }
5625 {
5631 {
5634 }
5643 {
5645 {
5648 }
5655 {
5663 {
5665 gnu_result
5666 = build_call_raise_range
5672 }
5673 }
5674 }
5677 {
5682 }
5683 else
5684 {
5687 /* If the type is VOID, this is a statement, so we need to generate
5688 the code for the call. Handle a Condition, if there is one. */
5690 {
5696 }
5697 else
5699 }
5700 }
5704 {
5709 /* No need for any warning in this case. */
5711 ;
5713 /* If the result is a pointer type, see if we are either converting
5714 from a non-pointer or from a pointer to a type with a different
5715 alias set and warn if so. If the result is defined in the same
5716 unit as this unchecked conversion, we can allow this because we
5717 can know to make the pointer type behave properly. */
5721 {
5734 || !alias_sets_conflict_p
5737 {
5738 post_error_ne
5741 post_error
5743 gnat_node);
5744 post_error_ne
5747 }
5748 }
5750 /* But if the result is a fat pointer type, we have no mechanism to
5751 do that, so we unconditionally warn in problematic cases. */
5753 {
5754 tree gnu_source_array_type
5758 tree gnu_target_array_type
5768 || !alias_sets_conflict_p
5771 {
5772 post_error_ne
5775 post_error
5777 gnat_node);
5778 }
5779 }
5780 }
5785 /* SCIL nodes require no processing for GCC. Other nodes should only
5786 be present when annotating types. */
5789 }
5791 /* If we pushed the processing of the elaboration routine, pop it back. */
5795 /* When not optimizing, turn boolean rvalues B into B != false tests
5796 so that the code just below can put the location information of the
5797 reference to B on the inequality operator for better debug info. */
5811 boolean_false_node));
5813 /* Set the location information on the result. Note that we may have
5814 no result if we tried to build a CALL_EXPR node to a procedure with
5815 no side-effects and optimization is enabled. */
5819 /* If we're supposed to return something of void_type, it means we have
5820 something we're elaborating for effect, so just return. */
5824 /* If the result is a constant that overflowed, raise Constraint_Error. */
5826 {
5828 gnu_result
5831 N_Raise_Constraint_Error));
5832 }
5834 /* If our result has side-effects and is of an unconstrained type,
5835 make a SAVE_EXPR so that we can be sure it will only be referenced
5836 once. Note we must do this before any conversions. */
5842 /* Now convert the result to the result type, unless we are in one of the
5843 following cases:
5845 1. If this is the Name of an assignment statement or a parameter of
5846 a procedure call, return the result almost unmodified since the
5847 RHS will have to be converted to our type in that case, unless
5848 the result type has a simpler size. Likewise if there is just
5849 a no-op unchecked conversion in-between. Similarly, don't convert
5850 integral types that are the operands of an unchecked conversion
5851 since we need to ignore those conversions (for 'Valid).
5853 2. If we have a label (which doesn't have any well-defined type), a
5854 field or an error, return the result almost unmodified. Also don't
5855 do the conversion if the result type involves a PLACEHOLDER_EXPR in
5856 its size since those are the cases where the front end may have the
5857 type wrong due to "instantiating" the unconstrained record with
5858 discriminant values. Similarly, if the two types are record types
5859 with the same name don't convert. This will be the case when we are
5860 converting from a packable version of a type to its original type and
5861 we need those conversions to be NOPs in order for assignments into
5862 these types to work properly.
5864 3. If the type is void or if we have no result, return error_mark_node
5865 to show we have no result.
5867 4. Finally, if the type of the result is already correct. */
5889 && (CONTAINS_PLACEHOLDER_P
5893 {
5894 /* Remove padding only if the inner object is of self-referential
5895 size: in that case it must be an object of unconstrained type
5896 with a default discriminant and we want to avoid copying too
5897 much data. */
5902 gnu_result);
5903 }
5916 {
5917 /* Remove any padding. */
5920 gnu_result);
5921 }
5929 /* We don't need any NOP_EXPR or NON_LVALUE_EXPR on the result. */
5936 }
5937 \f
5938 /* Subroutine of above to push the exception label stack. GNU_STACK is
5939 a pointer to the stack to update and GNAT_LABEL, if present, is the
5940 label to push onto the stack. */
5942 static void
5944 {
5950 }
5951 \f
5952 /* Record the current code position in GNAT_NODE. */
5954 static void
5956 {
5961 }
5963 /* Insert the code for GNAT_NODE at the position saved for that node. */
5965 static void
5967 {
5970 }
5971 \f
5972 /* Start a new statement group chained to the previous group. */
5974 void
5976 {
5979 /* First see if we can get one from the free list. */
5982 else
5988 }
5990 /* Add GNU_STMT to the current statement group. If it is an expression with
5991 no effects, it is ignored. */
5993 void
5995 {
5997 }
5999 /* Similar, but the statement is always added, regardless of side-effects. */
6001 void
6003 {
6005 }
6007 /* Like add_stmt, but set the location of GNU_STMT to that of GNAT_NODE. */
6009 void
6011 {
6015 }
6017 /* Similar, but the statement is always added, regardless of side-effects. */
6019 void
6021 {
6025 }
6027 /* Add a declaration statement for GNU_DECL to the current statement group.
6028 Get SLOC from Entity_Id. */
6030 void
6032 {
6036 /* If this is a variable that Gigi is to ignore, we may have been given
6037 an ERROR_MARK. So test for it. We also might have been given a
6038 reference for a renaming. So only do something for a decl. Also
6039 ignore a TYPE_DECL for an UNCONSTRAINED_ARRAY_TYPE. */
6047 /* If we are global, we don't want to actually output the DECL_EXPR for
6048 this decl since we already have evaluated the expressions in the
6049 sizes and positions as globals and doing it again would be wrong. */
6051 {
6052 /* Mark everything as used to prevent node sharing with subprograms.
6053 Note that walk_tree knows how to deal with TYPE_DECL, but neither
6054 VAR_DECL nor CONST_DECL. This appears to be somewhat arbitrary. */
6058 {
6062 }
6063 /* In any case, we have to deal with our own TYPE_ADA_SIZE field. */
6070 }
6074 /* If this is a variable and an initializer is attached to it, it must be
6075 valid for the context. Similar to init_const in create_var_decl_1. */
6082 {
6083 /* If GNU_DECL has a padded type, convert it to the unpadded
6084 type so the assignment is done properly. */
6087 else
6094 {
6097 }
6100 }
6101 }
6103 /* Callback for walk_tree to mark the visited trees rooted at *TP. */
6105 static tree
6107 {
6113 /* Don't mark a dummy type as visited because we want to mark its sizes
6114 and fields once it's filled in. */
6122 }
6124 /* Mark nodes rooted at T with TREE_VISITED and types as having their
6125 sized gimplified. We use this to indicate all variable sizes and
6126 positions in global types may not be shared by any subprogram. */
6128 void
6130 {
6132 }
6134 /* Add GNU_CLEANUP, a cleanup action, to the current code group and
6135 set its location to that of GNAT_NODE if present. */
6137 static void
6139 {
6143 }
6145 /* Set the BLOCK node corresponding to the current code group to GNU_BLOCK. */
6147 void
6149 {
6152 }
6154 /* Return code corresponding to the current code group. It is normally
6155 a STATEMENT_LIST, but may also be a BIND_EXPR or TRY_FINALLY_EXPR if
6156 BLOCK or cleanups were set. */
6158 tree
6160 {
6164 /* If this is a null list, allocate a new STATEMENT_LIST. Then, if there
6165 are cleanups, make a TRY_FINALLY_EXPR. Last, if there is a BLOCK,
6166 make a BIND_EXPR. Note that we nest in that because the cleanup may
6167 reference variables in the block. */
6179 /* Remove this group from the stack and add it to the free list. */
6185 }
6187 /* Add a list of statements from GNAT_LIST, a possibly-empty list of
6188 statements.*/
6190 static void
6192 {
6193 Node_Id gnat_node;
6199 }
6201 /* Build a tree from GNAT_LIST, a possibly-empty list of statements.
6202 If BINDING_P is true, push and pop a binding level around the list. */
6204 static tree
6206 {
6216 }
6217 \f
6218 /* Generate GIMPLE in place for the expression at *EXPR_P. */
6220 int
6223 {
6225 tree op;
6231 {
6233 /* If this is for a scalar, just make a VAR_DECL for it. If for
6234 an aggregate, get a null pointer of the appropriate type and
6235 dereference it. */
6239 integer_zero_node));
6240 else
6241 {
6244 }
6250 /* We should only do this if we are just elaborating for side-effects,
6251 but we can't know that yet. */
6258 /* If we are taking the address of a constant CONSTRUCTOR, make sure it
6259 is put into static memory. We know that it's going to be read-only
6260 given the semantics we have and it must be in static memory when the
6261 reference is in an elaboration procedure. */
6263 {
6267 }
6269 /* Otherwise, if we are taking the address of a non-constant CONSTRUCTOR
6270 or of a call, explicitly create the local temporary. That's required
6271 if the type is passed by reference. */
6273 {
6284 }
6291 /* The expressions for the RM bounds must be gimplified to ensure that
6292 they are properly elaborated. See gimplify_decl_expr. */
6296 {
6301 {
6306 {
6310 }
6314 {
6318 }
6320 }
6325 }
6327 /* ... fall through ... */
6331 }
6332 }
6334 /* Generate GIMPLE in place for the statement at *STMT_P. */
6336 static enum gimplify_status
6338 {
6342 {
6348 {
6353 tree t;
6355 /* Build the condition expression from the test, if any. */
6357 gnu_cond
6361 /* Set to emit the statements of the loop. */
6364 /* We first emit the start label and then a conditional jump to the
6365 end label if there's a top condition, then the update if it's at
6366 the top, then the body of the loop, then a conditional jump to
6367 the end label if there's a bottom condition, then the update if
6368 it's at the bottom, and finally a jump to the start label and the
6369 definition of the end label. */
6371 gnu_start_label),
6372 stmt_p);
6393 gnu_end_label),
6394 stmt_p);
6396 }
6399 /* Build a statement to jump to the corresponding end label, then
6400 see if it needs to be conditional. */
6409 }
6410 }
6411 \f
6412 /* Force references to each of the entities in packages withed by GNAT_NODE.
6413 Operate recursively but check that we aren't elaborating something more
6414 than once.
6416 This routine is exclusively called in type_annotate mode, to compute DDA
6417 information for types in withed units, for ASIS use. */
6419 static void
6421 {
6424 /* Process each unit only once. As we trace the context of all relevant
6425 units transitively, including generic bodies, we may encounter the
6426 same generic unit repeatedly. */
6430 /* Save entities in all context units. A body may have an implicit_with
6431 on its own spec, if the context includes a child unit, so don't save
6432 the spec twice. */
6439 {
6443 {
6460 }
6462 {
6463 Node_Id gnat_body
6466 /* Retrieve compilation unit node of generic body. */
6471 /* If body is available, elaborate its context. */
6474 }
6475 }
6479 }
6480 \f
6481 /* Do the processing of GNAT_NODE, an N_Freeze_Entity. */
6483 static void
6485 {
6490 /* If this is a package, we need to generate code for the package. */
6492 {
6493 insert_code_for
6497 }
6499 /* Don't do anything for class-wide types as they are always transformed
6500 into their root type. */
6504 /* Check for an old definition. This freeze node might be for an Itype. */
6505 gnu_old
6508 /* If this entity has an address representation clause, GNU_OLD is the
6509 address, so discard it here. */
6513 /* Don't do anything for subprograms that may have been elaborated before
6514 their freeze nodes. This can happen, for example, because of an inner
6515 call in an instance body or because of previous compilation of a spec
6516 for inlining purposes. */
6524 /* If we have a non-dummy type old tree, we have nothing to do, except
6525 aborting if this is the public view of a private type whose full view was
6526 not delayed, as this node was never delayed as it should have been. We
6527 let this happen for concurrent types and their Corresponding_Record_Type,
6528 however, because each might legitimately be elaborated before its own
6529 freeze node, e.g. while processing the other. */
6533 {
6541 }
6543 /* Reset the saved tree, if any, and elaborate the object or type for real.
6544 If there is a full view, elaborate it and use the result. And, if this
6545 is the root type of a class-wide type, reuse it for the latter. */
6547 {
6557 }
6561 {
6564 /* Propagate back-annotations from full view to partial view. */
6574 /* The above call may have defined this entity (the simplest example
6575 of this is when we have a private enumeral type since the bounds
6576 will have the public view). */
6579 }
6580 else
6581 {
6582 tree gnu_init
6588 }
6595 /* If we've made any pointers to the old version of this type, we
6596 have to update them. */
6600 }
6601 \f
6602 /* Elaborate decls in the lists GNAT_DECLS and GNAT_DECLS2, if present.
6603 We make two passes, one to elaborate anything other than bodies (but
6604 we declare a function if there was no spec). The second pass
6605 elaborates the bodies.
6607 GNAT_END_LIST gives the element in the list past the end. Normally,
6608 this is Empty, but can be First_Real_Statement for a
6609 Handled_Sequence_Of_Statements.
6611 We make a complete pass through both lists if PASS1P is true, then make
6612 the second pass over both lists if PASS2P is true. The lists usually
6613 correspond to the public and private parts of a package. */
6615 static void
6618 {
6620 Node_Id gnat_decl;
6630 {
6631 /* For package specs, we recurse inside the declarations,
6632 thus taking the two pass approach inside the boundary. */
6640 /* Similarly for any declarations in the actions of a
6641 freeze node. */
6643 {
6646 }
6648 /* Package bodies with freeze nodes get their elaboration deferred
6649 until the freeze node, but the code must be placed in the right
6650 place, so record the code position now. */
6658 (Corresponding_Spec
6661 record_code_position
6664 /* We defer most subprogram bodies to the second pass. */
6666 {
6668 {
6674 }
6675 }
6677 /* For bodies and stubs that act as their own specs, the entity
6678 itself must be elaborated in the first pass, because it may
6679 be used in other declarations. */
6681 {
6682 Node_Id gnat_subprog_id
6689 }
6691 /* Concurrent stubs stand for the corresponding subprogram bodies,
6692 which are deferred like other bodies. */
6695 ;
6697 else
6699 }
6701 /* Here we elaborate everything we deferred above except for package bodies,
6702 which are elaborated at their freeze nodes. Note that we must also
6703 go inside things (package specs and freeze nodes) the first pass did. */
6709 {
6725 }
6726 }
6727 \f
6728 /* Make a unary operation of kind CODE using build_unary_op, but guard
6729 the operation by an overflow check. CODE can be one of NEGATE_EXPR
6730 or ABS_EXPR. GNU_TYPE is the type desired for the result. Usually
6731 the operation is to be performed in that type. GNAT_NODE is the gnat
6732 node conveying the source location for which the error should be
6733 signaled. */
6735 static tree
6737 Node_Id gnat_node)
6738 {
6747 }
6749 /* Make a binary operation of kind CODE using build_binary_op, but guard
6750 the operation by an overflow check. CODE can be one of PLUS_EXPR,
6751 MINUS_EXPR or MULT_EXPR. GNU_TYPE is the type desired for the result.
6752 Usually the operation is to be performed in that type. GNAT_NODE is
6753 the GNAT node conveying the source location for which the error should
6754 be signaled. */
6756 static tree
6759 {
6764 tree gnu_expr;
6767 tree rhs_lt_zero;
6768 tree check_pos;
6769 tree check_neg;
6770 tree check;
6775 /* Prefer a constant or known-positive rhs to simplify checks. */
6780 {
6784 }
6787 ? boolean_false_node
6790 /* ??? Should use more efficient check for operand_equal_p (lhs, rhs, 0) */
6792 /* Try a few strategies that may be cheaper than the general
6793 code at the end of the function, if the rhs is not known.
6794 The strategies are:
6795 - Call library function for 64-bit multiplication (complex)
6796 - Widen, if input arguments are sufficiently small
6797 - Determine overflow using wrapped result for addition/subtraction. */
6800 {
6801 /* Even for add/subtract double size to get another base type. */
6805 {
6811 }
6816 {
6823 tree check = build_binary_op
6832 return
6834 }
6837 {
6839 tree wrapped_expr = convert
6844 tree result = convert
6847 /* Overflow when (rhs < 0) ^ (wrapped_expr < lhs)), for addition
6848 or when (rhs < 0) ^ (wrapped_expr > lhs) for subtraction. */
6849 tree check = build_binary_op
6854 return
6856 }
6857 }
6860 {
6862 /* When rhs >= 0, overflow when lhs > type_max - rhs. */
6867 /* When rhs < 0, overflow when lhs < type_min - rhs. */
6874 /* When rhs >= 0, overflow when lhs < type_min + rhs. */
6879 /* When rhs < 0, overflow when lhs > type_max + rhs. */
6886 /* The check here is designed to be efficient if the rhs is constant,
6887 but it will work for any rhs by using integer division.
6888 Four different check expressions determine whether X * C overflows,
6889 depending on C.
6890 C == 0 => false
6891 C > 0 => X > type_max / C || X < type_min / C
6892 C == -1 => X == type_min
6893 C < -1 => X > type_min / C || X < type_max / C */
6898 check_pos
6901 rhs),
6904 boolean_type_node,
6907 boolean_type_node,
6910 check_neg
6915 type_min),
6918 boolean_type_node,
6921 boolean_type_node,
6927 }
6931 /* If we can fold the expression to a constant, just return it.
6932 The caller will deal with overflow, no need to generate a check. */
6937 check_pos);
6940 }
6942 /* Emit code for a range check. GNU_EXPR is the expression to be checked,
6943 GNAT_RANGE_TYPE the gnat type or subtype containing the bounds against
6944 which we have to check. GNAT_NODE is the GNAT node conveying the source
6945 location for which the error should be signaled. */
6947 static tree
6949 {
6955 /* If GNU_EXPR has GNAT_RANGE_TYPE as its base type, no check is needed.
6956 This can for example happen when translating 'Val or 'Value. */
6960 /* If GNU_EXPR has an integral type that is narrower than GNU_RANGE_TYPE,
6961 we can't do anything since we might be truncating the bounds. No
6962 check is needed in this case. */
6968 /* Checked expressions must be evaluated only once. */
6971 /* Note that the form of the check is
6972 (not (expr >= lo)) or (not (expr <= hi))
6973 the reason for this slightly convoluted form is that NaNs
6974 are not considered to be in range in the float case. */
6975 return emit_check
6977 invert_truthvalue
6981 invert_truthvalue
6985 gnu_high)))),
6987 }
6988 \f
6989 /* Emit code for an index check. GNU_ARRAY_OBJECT is the array object which
6990 we are about to index, GNU_EXPR is the index expression to be checked,
6991 GNU_LOW and GNU_HIGH are the lower and upper bounds against which GNU_EXPR
6992 has to be checked. Note that for index checking we cannot simply use the
6993 emit_range_check function (although very similar code needs to be generated
6994 in both cases) since for index checking the array type against which we are
6995 checking the indices may be unconstrained and consequently we need to get
6996 the actual index bounds from the array object itself (GNU_ARRAY_OBJECT).
6997 The place where we need to do that is in subprograms having unconstrained
6998 array formal parameters. GNAT_NODE is the GNAT node conveying the source
6999 location for which the error should be signaled. */
7001 static tree
7004 {
7005 tree gnu_expr_check;
7007 /* Checked expressions must be evaluated only once. */
7010 /* Must do this computation in the base type in case the expression's
7011 type is an unsigned subtypes. */
7014 /* If GNU_LOW or GNU_HIGH are a PLACEHOLDER_EXPR, qualify them by
7015 the object we are handling. */
7019 return emit_check
7022 gnu_expr_check,
7024 gnu_low)),
7026 gnu_expr_check,
7028 gnu_high))),
7030 }
7031 \f
7032 /* GNU_COND contains the condition corresponding to an access, discriminant or
7033 range check of value GNU_EXPR. Build a COND_EXPR that returns GNU_EXPR if
7034 GNU_COND is false and raises a CONSTRAINT_ERROR if GNU_COND is true.
7035 REASON is the code that says why the exception was raised. GNAT_NODE is
7036 the GNAT node conveying the source location for which the error should be
7037 signaled. */
7039 static tree
7041 {
7042 tree gnu_call
7044 tree gnu_result
7048 gnu_expr);
7050 /* GNU_RESULT has side effects if and only if GNU_EXPR has:
7051 we don't need to evaluate it just for the check. */
7055 }
7056 \f
7057 /* Return an expression that converts GNU_EXPR to GNAT_TYPE, doing overflow
7058 checks if OVERFLOW_P is true and range checks if RANGE_P is true.
7059 GNAT_TYPE is known to be an integral type. If TRUNCATE_P true, do a
7060 float to integer conversion with truncation; otherwise round.
7061 GNAT_NODE is the GNAT node conveying the source location for which the
7062 error should be signaled. */
7064 static tree
7067 {
7074 /* If we are not doing any checks, the output is an integral type, and
7075 the input is not a floating type, just do the conversion. This
7076 shortcut is required to avoid problems with packed array types
7077 and simplifies code in all cases anyway. */
7082 /* First convert the expression to its base type. This
7083 will never generate code, but makes the tests below much simpler.
7084 But don't do this if converting from an integer type to an unconstrained
7085 array type since then we need to get the bounds from the original
7086 (unpacked) type. */
7090 /* If overflow checks are requested, we need to be sure the result will
7091 fit in the output base type. But don't do this if the input
7092 is integer and the output floating-point. */
7095 {
7096 /* Ensure GNU_EXPR only gets evaluated once. */
7104 /* Convert the lower bounds to signed types, so we're sure we're
7105 comparing them properly. Likewise, convert the upper bounds
7106 to unsigned types. */
7120 /* Check each bound separately and only if the result bound
7121 is tighter than the bound on the input type. Note that all the
7122 types are base types, so the bounds must be constant. Also,
7123 the comparison is done in the base type of the input, which
7124 always has the proper signedness. First check for input
7125 integer (which means output integer), output float (which means
7126 both float), or mixed, in which case we always compare.
7127 Note that we have to do the comparison which would *fail* in the
7128 case of an error since if it's an FP comparison and one of the
7129 values is a NaN or Inf, the comparison will fail. */
7136 gnu_cond
7137 = invert_truthvalue
7140 gnu_out_lb)));
7148 gnu_cond
7150 invert_truthvalue
7152 gnu_input,
7154 gnu_out_ub))));
7159 }
7161 /* Now convert to the result base type. If this is a non-truncating
7162 float-to-integer conversion, round. */
7165 {
7171 /* The following calculations depend on proper rounding to even
7172 of each arithmetic operation. In order to prevent excess
7173 precision from spoiling this property, use the widest hardware
7174 floating-point type if FP_ARITH_MAY_WIDEN is true. */
7175 calc_type
7178 /* FIXME: Should not have padding in the first place. */
7182 /* Compute the exact value calc_type'Pred (0.5) at compile time. */
7186 half_minus_pred_half);
7189 /* If the input is strictly negative, subtract this value
7190 and otherwise add it from the input. For 0.5, the result
7191 is exactly between 1.0 and the machine number preceding 1.0
7192 (for calc_type). Since the last bit of 1.0 is even, this 0.5
7193 will round to 1.0, while all other number with an absolute
7194 value less than 0.5 round to 0.0. For larger numbers exactly
7195 halfway between integers, rounding will always be correct as
7196 the true mathematical result will be closer to the higher
7197 integer compared to the lower one. So, this constant works
7198 for all floating-point numbers.
7200 The reason to use the same constant with subtract/add instead
7201 of a positive and negative constant is to allow the comparison
7202 to be scheduled in parallel with retrieval of the constant and
7203 conversion of the input to the calc_type (if necessary). */
7208 gnu_comp
7210 gnu_add_pred_half
7212 gnu_subtract_pred_half
7216 }
7222 else
7225 /* Finally, do the range check if requested. Note that if the result type
7226 is a modular type, the range check is actually an overflow check. */
7233 }
7234 \f
7235 /* Return true if TYPE is a smaller form of ORIG_TYPE. */
7237 static bool
7239 {
7242 /* We're not interested in variants here. */
7246 /* Like a variant, a packable version keeps the original TYPE_NAME. */
7257 }
7259 /* Return true if GNU_EXPR can be directly addressed. This is the case
7260 unless it is an expression involving computation or if it involves a
7261 reference to a bitfield or to an object not sufficiently aligned for
7262 its type. If GNU_TYPE is non-null, return true only if GNU_EXPR can
7263 be directly addressed as an object of this type.
7265 *** Notes on addressability issues in the Ada compiler ***
7267 This predicate is necessary in order to bridge the gap between Gigi
7268 and the middle-end about addressability of GENERIC trees. A tree
7269 is said to be addressable if it can be directly addressed, i.e. if
7270 its address can be taken, is a multiple of the type's alignment on
7271 strict-alignment architectures and returns the first storage unit
7272 assigned to the object represented by the tree.
7274 In the C family of languages, everything is in practice addressable
7275 at the language level, except for bit-fields. This means that these
7276 compilers will take the address of any tree that doesn't represent
7277 a bit-field reference and expect the result to be the first storage
7278 unit assigned to the object. Even in cases where this will result
7279 in unaligned accesses at run time, nothing is supposed to be done
7280 and the program is considered as erroneous instead (see PR c/18287).
7282 The implicit assumptions made in the middle-end are in keeping with
7283 the C viewpoint described above:
7284 - the address of a bit-field reference is supposed to be never
7285 taken; the compiler (generally) will stop on such a construct,
7286 - any other tree is addressable if it is formally addressable,
7287 i.e. if it is formally allowed to be the operand of ADDR_EXPR.
7289 In Ada, the viewpoint is the opposite one: nothing is addressable
7290 at the language level unless explicitly declared so. This means
7291 that the compiler will both make sure that the trees representing
7292 references to addressable ("aliased" in Ada parlance) objects are
7293 addressable and make no real attempts at ensuring that the trees
7294 representing references to non-addressable objects are addressable.
7296 In the first case, Ada is effectively equivalent to C and handing
7297 down the direct result of applying ADDR_EXPR to these trees to the
7298 middle-end works flawlessly. In the second case, Ada cannot afford
7299 to consider the program as erroneous if the address of trees that
7300 are not addressable is requested for technical reasons, unlike C;
7301 as a consequence, the Ada compiler must arrange for either making
7302 sure that this address is not requested in the middle-end or for
7303 compensating by inserting temporaries if it is requested in Gigi.
7305 The first goal can be achieved because the middle-end should not
7306 request the address of non-addressable trees on its own; the only
7307 exception is for the invocation of low-level block operations like
7308 memcpy, for which the addressability requirements are lower since
7309 the type's alignment can be disregarded. In practice, this means
7310 that Gigi must make sure that such operations cannot be applied to
7311 non-BLKmode bit-fields.
7313 The second goal is achieved by means of the addressable_p predicate,
7314 which computes whether a temporary must be inserted by Gigi when the
7315 address of a tree is requested; if so, the address of the temporary
7316 will be used in lieu of that of the original tree and some glue code
7317 generated to connect everything together. */
7319 static bool
7321 {
7322 /* For an integral type, the size of the actual type of the object may not
7323 be greater than that of the expected type, otherwise an indirect access
7324 in the latter type wouldn't correctly set all the bits of the object. */
7330 /* The size of the actual type of the object may not be smaller than that
7331 of the expected type, otherwise an indirect access in the latter type
7332 would be larger than the object. But only record types need to be
7333 considered in practice for this case. */
7340 {
7345 /* All DECLs are addressable: if they are in a register, we can force
7346 them to memory. */
7351 /* Taking the address of a dereference yields the original pointer. */
7356 /* Taking the address yields a pointer to the constant pool. */
7360 /* Taking the address of a static constructor yields a pointer to the
7361 tree constant pool. */
7373 /* All rvalues are deemed addressable since taking their address will
7374 force a temporary to be created by the middle-end. */
7378 /* The address of a compound expression is that of its 2nd operand. */
7382 /* We accept &COND_EXPR as soon as both operands are addressable and
7383 expect the outcome to be the address of the selected operand. */
7389 /* Even with DECL_BIT_FIELD cleared, we have to ensure that
7390 the field is sufficiently aligned, in case it is subject
7391 to a pragma Component_Alignment. But we don't need to
7392 check the alignment of the containing record, as it is
7393 guaranteed to be not smaller than that of its most
7394 aligned field that is not a bit-field. */
7395 && (!STRICT_ALIGNMENT
7398 /* The field of a padding record is always addressable. */
7412 {
7413 /* This is addressable if we can avoid a copy. */
7417 && (!STRICT_ALIGNMENT
7422 && (!STRICT_ALIGNMENT
7428 }
7432 }
7433 }
7434 \f
7435 /* Do the processing for the declaration of a GNAT_ENTITY, a type. If
7436 a separate Freeze node exists, delay the bulk of the processing. Otherwise
7437 make a GCC type for GNAT_ENTITY and set up the correspondence. */
7439 void
7441 {
7442 tree gnu_old
7444 tree gnu_new;
7446 /* If we are to delay elaboration of this type, just do any
7447 elaborations needed for expressions within the declaration and
7448 make a dummy type entry for this node and its Full_View (if
7449 any) in case something points to it. Don't do this if it
7450 has already been done (the only way that can happen is if
7451 the private completion is also delayed). */
7457 {
7461 {
7467 }
7470 }
7472 /* If we saved away a dummy type for this node it means that this
7473 made the type that corresponds to the full type of an incomplete
7474 type. Clear that type for now and then update the type in the
7475 pointers. */
7477 {
7482 }
7484 /* Now fully elaborate the type. */
7488 /* If we have an old type and we've made pointers to this type,
7489 update those pointers. */
7494 /* If this is a record type corresponding to a task or protected type
7495 that is a completion of an incomplete type, perform a similar update
7496 on the type. ??? Including protected types here is a guess. */
7500 {
7501 tree gnu_task_old
7511 }
7512 }
7513 \f
7514 /* GNAT_ENTITY is the type of the resulting constructors,
7515 GNAT_ASSOC is the front of the Component_Associations of an N_Aggregate,
7516 and GNU_TYPE is the GCC type of the corresponding record.
7518 Return a CONSTRUCTOR to build the record. */
7520 static tree
7522 {
7525 /* We test for GNU_FIELD being empty in the case where a variant
7526 was the last thing since we don't take things off GNAT_ASSOC in
7527 that case. We check GNAT_ASSOC in case we have a variant, but it
7528 has no fields. */
7532 {
7537 /* The expander is supposed to put a single component selector name
7538 in every record component association. */
7541 /* Ignore fields that have Corresponding_Discriminants since we'll
7542 be setting that field in the parent. */
7547 /* Also ignore discriminants of Unchecked_Unions. */
7552 /* Before assigning a value in an aggregate make sure range checks
7553 are done if required. Then convert to the type of the field. */
7559 /* Add the field and expression to the list. */
7561 }
7565 #ifdef ENABLE_CHECKING
7566 {
7567 tree gnu_field;
7569 /* Verify every entry in GNU_LIST was used. */
7572 }
7573 #endif
7576 }
7578 /* Build a possibly nested constructor for array aggregates. GNAT_EXPR is
7579 the first element of an array aggregate. It may itself be an aggregate.
7580 GNU_ARRAY_TYPE is the GCC type corresponding to the array aggregate.
7581 GNAT_COMPONENT_TYPE is the type of the array component; it is needed
7582 for range checking. */
7584 static tree
7586 Entity_Id gnat_component_type)
7587 {
7589 tree gnu_expr;
7593 {
7594 /* If the expression is itself an array aggregate then first build the
7595 innermost constructor if it is part of our array (multi-dimensional
7596 case). */
7602 gnat_component_type);
7603 else
7604 {
7607 /* Before assigning the element to the array, make sure it is
7608 in range. */
7611 }
7617 }
7620 }
7621 \f
7622 /* Subroutine of assoc_to_constructor: VALUES is a list of field associations,
7623 some of which are from RECORD_TYPE. Return a CONSTRUCTOR consisting
7624 of the associations that are from RECORD_TYPE. If we see an internal
7625 record, make a recursive call to fill it in as well. */
7627 static tree
7629 {
7634 {
7637 /* _Parent is an internal field, but may have values in the aggregate,
7638 so check for values first. */
7640 {
7643 }
7646 {
7651 }
7652 else
7653 /* If we have a record subtype, the names will match, but not the
7654 actual FIELD_DECLs. */
7657 {
7660 }
7666 }
7669 }
7670 \f
7671 /* EXP is to be treated as an array or record. Handle the cases when it is
7672 an access object and perform the required dereferences. */
7674 static tree
7676 {
7677 /* If the type is a pointer, dereference it. */
7682 /* If we got a padded type, remove it too. */
7687 }
7688 \f
7689 /* Convert SLOC into LOCUS. Return true if SLOC corresponds to a source code
7690 location and false if it doesn't. In the former case, set the Gigi global
7691 variable REF_FILENAME to the simple debug file name as given by sinput. */
7693 bool
7695 {
7700 {
7703 }
7704 else
7705 {
7711 /* Translate the location according to the line-map.h formula. */
7715 }
7717 ref_filename
7718 = IDENTIFIER_POINTER
7719 (get_identifier
7723 }
7725 /* Similar to set_expr_location, but start with the Sloc of GNAT_NODE and
7726 don't do anything if it doesn't correspond to a source location. */
7728 static void
7730 {
7731 location_t locus;
7737 }
7739 /* More elaborate version of set_expr_location_from_node to be used in more
7740 general contexts, for example the result of the translation of a generic
7741 GNAT node. */
7743 static void
7745 {
7746 /* Set the location information on the node if it is a real expression.
7747 References can be reused for multiple GNAT nodes and they would get
7748 the location information of their last use. Also make sure not to
7749 overwrite an existing location as it is probably more precise. */
7752 {
7753 CASE_CONVERT:
7761 /* ... fall through ... */
7767 }
7768 }
7769 \f
7770 /* Return a colon-separated list of encodings contained in encoded Ada
7771 name. */
7775 {
7779 }
7781 /* Extract the Ada name from an encoded name. */
7785 {
7789 }
7790 \f
7791 /* Post an error message. MSG is the error message, properly annotated.
7792 NODE is the node at which to post the error and the node to use for the
7793 '&' substitution. */
7795 void
7797 {
7798 String_Template temp;
7799 Fat_Pointer fp;
7805 }
7807 /* Similar to post_error, but NODE is the node at which to post the error and
7808 ENT is the node to use for the '&' substitution. */
7810 void
7812 {
7813 String_Template temp;
7814 Fat_Pointer fp;
7820 }
7822 /* Similar to post_error_ne, but NUM is the number to use for the '^'. */
7824 void
7826 {
7829 }
7830 \f
7831 /* Similar to post_error_ne, but T is a GCC tree representing the number to
7832 write. If T represents a constant, the text inside curly brackets in
7833 MSG will be output (presumably including a '^'). Otherwise it will not
7834 be output and the text inside square brackets will be output instead. */
7836 void
7838 {
7845 {
7848 }
7849 else
7853 {
7859 ;
7860 else
7862 }
7867 }
7869 /* Similar to post_error_ne_tree, but NUM is a second integer to write. */
7871 void
7874 {
7877 }
7878 \f
7879 /* Initialize the table that maps GNAT codes to GCC codes for simple
7880 binary and unary operations. */
7882 static void
7884 {
7910 }
7912 /* Return a label to branch to for the exception type in KIND or NULL_TREE
7913 if none. */
7915 tree
7917 {
7924 else
7926 }
7928 /* Return the decl for the current elaboration procedure. */
7930 tree
7932 {
7934 }