| blob | d0f764bbea39f96927b12c07f9f2b59799f0abde |
1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * T R A N S *
6 * *
7 * C Implementation File *
8 * *
9 * Copyright (C) 1992-2014, 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 ****************************************************************************/
77 /* We should avoid allocating more than ALLOCA_THRESHOLD bytes via alloca,
78 for fear of running out of stack space. If we need more, we use xmalloc
79 instead. */
80 #define ALLOCA_THRESHOLD 1000
82 /* In configurations where blocks have no end_locus attached, just
83 sink assignments into a dummy global. */
84 #ifndef BLOCK_SOURCE_END_LOCATION
86 #define BLOCK_SOURCE_END_LOCATION(BLOCK) block_end_locus_sink
87 #endif
89 /* Pointers to front-end tables accessed through macros. */
100 /* Highest number in the front-end node table. */
103 /* Current node being treated, in case abort called. */
104 Node_Id error_gnat_node;
106 /* True when gigi is being called on an analyzed but unexpanded
107 tree, and the only purpose of the call is to properly annotate
108 types with representation information. */
111 /* Current filename without path. */
115 /* List of N_Validate_Unchecked_Conversion nodes in the unit. */
118 /* When not optimizing, we cache the 'First, 'Last and 'Length attributes
119 of unconstrained array IN parameters to avoid emitting a great deal of
120 redundant instructions to recompute them each time. */
124 tree first;
125 tree last;
126 tree length;
127 };
134 bitmap named_ret_val;
137 };
139 #define f_parm_attr_cache \
140 DECL_STRUCT_FUNCTION (current_function_decl)->language->parm_attr_cache
142 #define f_named_ret_val \
143 DECL_STRUCT_FUNCTION (current_function_decl)->language->named_ret_val
145 #define f_other_ret_val \
146 DECL_STRUCT_FUNCTION (current_function_decl)->language->other_ret_val
148 #define f_gnat_ret \
149 DECL_STRUCT_FUNCTION (current_function_decl)->language->gnat_ret
151 /* A structure used to gather together information about a statement group.
152 We use this to gather related statements, for example the "then" part
153 of a IF. In the case where it represents a lexical scope, we may also
154 have a BLOCK node corresponding to it and/or cleanups. */
161 };
165 /* List of unused struct stmt_group nodes. */
168 /* A structure used to record information on elaboration procedures
169 we've made and need to process.
171 ??? gnat_node should be Node_Id, but gengtype gets confused. */
177 };
181 /* Stack of exception pointer variables. Each entry is the VAR_DECL
182 that stores the address of the raised exception. Nonzero means we
183 are in an exception handler. Not used in the zero-cost case. */
186 /* In ZCX case, current exception pointer. Used to re-raise it. */
189 /* Stack for storing the current elaboration procedure decl. */
192 /* Stack of labels to be used as a goto target instead of a return in
193 some functions. See processing for N_Subprogram_Body. */
196 /* Stack of variable for the return value of a function with copy-in/copy-out
197 parameters. See processing for N_Subprogram_Body. */
200 /* Structure used to record information for a range check. */
202 tree low_bound;
203 tree high_bound;
204 tree type;
205 tree invariant_cond;
206 };
211 /* Structure used to record information for a loop. */
213 tree stmt;
214 tree loop_var;
216 };
221 /* Stack of loop_info structures associated with LOOP_STMT nodes. */
224 /* The stacks for N_{Push,Pop}_*_Label. */
229 /* Map GNAT tree codes to GCC tree codes for simple expressions. */
266 /* Hooks for debug info back-ends, only supported and used in a restricted set
267 of configurations. */
270 \f
271 /* This is the main program of the back-end. It sets up all the table
272 structures and then generates code. */
274 void
287 Nat number_file,
289 Entity_Id standard_boolean,
290 Entity_Id standard_integer,
291 Entity_Id standard_character,
292 Entity_Id standard_long_long_float,
293 Entity_Id standard_exception_type,
294 Int gigi_operating_mode)
295 {
296 Node_Id gnat_iter;
297 Entity_Id gnat_literal;
317 {
318 /* Use the identifier table to make a permanent copy of the filename as
319 the name table gets reallocated after Gigi returns but before all the
320 debugging information is output. The __gnat_to_canonical_file_spec
321 call translates filenames from pragmas Source_Reference that contain
322 host style syntax not understood by gdb. */
324 = IDENTIFIER_POINTER
325 (get_identifier
326 (__gnat_to_canonical_file_spec
329 /* We rely on the order isomorphism between files and line maps. */
332 /* We create the line map for a source file at once, with a fixed number
333 of columns chosen to avoid jumping over the next power of 2. */
338 }
342 /* Declare the name of the compilation unit as the first global
343 name in order to make the middle-end fully deterministic. */
347 /* Initialize ourselves. */
352 /* If we are just annotating types, give VOID_TYPE zero sizes to avoid
353 errors. */
355 {
358 }
360 /* Enable GNAT stack checking method if needed */
364 /* Retrieve alignment settings. */
368 /* Record the builtin types. Define `integer' and `character' first so that
369 dbx will output them first. */
375 /* Save the type we made for integer as the type for Standard.Integer. */
380 /* Likewise for character as the type for Standard.Character. */
385 /* Likewise for boolean as the type for Standard.Boolean. */
409 /* Now declare run-time functions. */
412 /* malloc is a function declaration tree for a function to allocate
413 memory. */
414 malloc_decl
420 /* free is a function declaration tree for a function to free memory. */
421 free_decl
424 ptr_void_type_node,
425 NULL_TREE),
427 Empty);
429 /* This is used for 64-bit multiplication with overflow checking. */
431 mulv64_decl
436 Empty);
438 /* Name of the _Parent field in tagged record types. */
441 /* Name of the Exception_Data type defined in System.Standard_Library. */
442 exception_data_name_id
445 /* Make the types and functions used for exception processing. */
446 jmpbuf_type
452 /* Functions to get and set the jumpbuf pointer for the current thread. */
453 get_jmpbuf_decl
454 = create_subprog_decl
460 set_jmpbuf_decl
461 = create_subprog_decl
464 NULL_TREE),
468 /* setjmp returns an integer and has one operand, which is a pointer to
469 a jmpbuf. */
470 setjmp_decl
471 = create_subprog_decl
474 NULL_TREE),
479 /* update_setjmp_buf updates a setjmp buffer from the current stack pointer
480 address. */
481 update_setjmp_buf_decl
482 = create_subprog_decl
489 /* Hooks to call when entering/leaving an exception handler. */
490 ftype
493 begin_handler_decl
499 end_handler_decl
505 unhandled_except_decl
507 NULL_TREE,
512 reraise_zcx_decl
516 /* Indicate that these never return. */
523 /* If in no exception handlers mode, all raise statements are redirected to
524 __gnat_last_chance_handler. No need to redefine raise_nodefer_decl since
525 this procedure will never be called in this mode. */
527 {
528 tree decl
529 = create_subprog_decl
532 build_pointer_type
542 }
543 else
544 {
545 /* Otherwise, make one decl for each exception reason. */
551 i == CE_Index_Check_Failed
555 }
557 /* Set the types that GCC and Gigi use from the front end. */
560 /* Make other functions used for exception processing. */
561 get_excptr_decl
562 = create_subprog_decl
565 NULL_TREE),
569 set_exception_parameter_decl
570 = create_subprog_decl
573 ptr_void_type_node,
574 ptr_void_type_node,
575 NULL_TREE),
578 raise_nodefer_decl
579 = create_subprog_decl
583 NULL_TREE),
586 /* Indicate that it never returns. */
591 TYPE_QUAL_VOLATILE);
593 /* Build the special descriptor type and its null node if needed. */
595 {
607 {
608 tree field
615 elt--;
616 }
621 }
623 longest_float_type_node
626 /* Dummy objects to materialize "others" and "all others" in the exception
627 tables. These are exported by a-exexpr-gcc.adb, so see this unit for
628 the types to use. */
629 others_decl
632 unsigned_char_type_node,
635 all_others_decl
638 unsigned_char_type_node,
641 unhandled_others_decl
644 unsigned_char_type_node,
649 /* Install the builtins we might need, either internally or as
650 user available facilities for Intrinsic imports. */
658 /* Process any Pragma Ident for the main unit. */
663 /* If we are using the GCC exception mechanism, let GCC know. */
667 /* Initialize the GCC support for FP operations. */
670 /* Now translate the compilation unit proper. */
673 /* Then process the N_Validate_Unchecked_Conversion nodes. We do this at
674 the very end to avoid having to second-guess the front-end when we run
675 into dummy nodes during the regular processing. */
680 /* Finally see if we have any elaboration procedures to deal with. */
682 {
685 /* We should have a BIND_EXPR but it may not have any statements in it.
686 If it doesn't have any, we have nothing to do except for setting the
687 flag on the GNAT node. Otherwise, process the function as others. */
693 else
694 {
698 }
699 }
701 /* Destroy ourselves. */
705 /* We cannot track the location of errors past this point. */
707 }
708 \f
709 /* Return a subprogram decl corresponding to __gnat_rcheck_xx for the given
710 CHECK if KIND is EXCEPTION_SIMPLE, or else to __gnat_rcheck_xx_ext. */
712 static tree
714 {
723 {
725 ftype
727 build_pointer_type
730 }
731 else
732 {
737 ftype
739 build_pointer_type
743 }
745 result
750 /* Indicate that it never returns. */
757 }
758 \f
759 /* Return a positive value if an lvalue is required for GNAT_NODE, which is
760 an N_Attribute_Reference. */
762 static int
764 {
766 {
806 }
807 }
809 /* Return a positive value if an lvalue is required for GNAT_NODE. GNU_TYPE
810 is the type that will be used for GNAT_NODE in the translated GNU tree.
811 CONSTANT indicates whether the underlying object represented by GNAT_NODE
812 is constant in the Ada sense. If it is, ADDRESS_OF_CONSTANT indicates
813 whether its value is the address of a constant and ALIASED whether it is
814 aliased. If it isn't, ADDRESS_OF_CONSTANT and ALIASED are ignored.
816 The function climbs up the GNAT tree starting from the node and returns 1
817 upon encountering a node that effectively requires an lvalue downstream.
818 It returns int instead of bool to facilitate usage in non-purely binary
819 logic contexts. */
821 static int
824 {
828 {
838 /* If the parameter is by reference, an lvalue is required. */
844 /* Only the array expression can require an lvalue. */
848 /* ??? Consider that referencing an indexed component with a
849 non-constant index forces the whole aggregate to memory.
850 Note that N_Integer_Literal is conservative, any static
851 expression in the RM sense could probably be accepted. */
858 /* ... fall through ... */
861 /* Only the array expression can require an lvalue. */
875 /* We need to preserve addresses through a renaming. */
879 /* We cannot use a constructor if this is an atomic object because
880 the actual assignment might end up being done component-wise. */
884 /* We don't use a constructor if this is a class-wide object
885 because the effective type of the object is the equivalent
886 type of the class-wide subtype and it smashes most of the
887 data into an array of bytes to which we cannot convert. */
892 /* We cannot use a constructor if the LHS is an atomic object because
893 the actual assignment might end up being done component-wise. */
903 /* ... fall through ... */
907 /* We must look through all conversions because we may need to bypass
908 an intermediate conversion that is meant to be purely formal. */
914 /* We should only reach here through the N_Qualified_Expression case.
915 Force an lvalue for composite types since a block-copy to the newly
916 allocated area of memory is made. */
920 /* We look through dereferences for address of constant because we need
921 to handle the special cases listed above. */
927 /* ... fall through ... */
931 }
934 }
936 /* Return true if T is a constant DECL node that can be safely replaced
937 by its initializer. */
939 static bool
941 {
945 /* Return false for aggregate types that contain a placeholder since
946 their initializers cannot be manipulated easily. */
953 }
955 /* Return an expression equivalent to EXP but where constant DECL nodes
956 have been replaced by their initializer. */
958 static tree
960 {
962 tree op0;
965 {
1002 }
1005 }
1007 /* Subroutine of gnat_to_gnu to translate gnat_node, an N_Identifier,
1008 to a GCC tree, which is returned. GNU_RESULT_TYPE_P is a pointer
1009 to where we should place the result type. */
1011 static tree
1013 {
1017 /* Whether we should require an lvalue for GNAT_NODE. Needed in
1018 specific circumstances only, so evaluated lazily. < 0 means
1019 unknown, > 0 means known true, 0 means known false. */
1022 /* If GNAT_NODE is a constant, whether we should use the initialization
1023 value instead of the constant entity, typically for scalars with an
1024 address clause when the parent doesn't require an lvalue. */
1027 /* If the Etype of this node does not equal the Etype of the Entity,
1028 something is wrong with the entity map, probably in generic
1029 instantiation. However, this does not apply to types. Since we sometime
1030 have strange Ekind's, just do this test for objects. Also, if the Etype of
1031 the Entity is private, the Etype of the N_Identifier is allowed to be the
1032 full type and also we consider a packed array type to be the same as the
1033 original type. Similarly, a class-wide type is equivalent to a subtype of
1034 itself. Finally, if the types are Itypes, one may be a copy of the other,
1035 which is also legal. */
1050 == Packed_Array_Impl_Type
1059 /* If this is a reference to a deferred constant whose partial view is an
1060 unconstrained private type, the proper type is on the full view of the
1061 constant, not on the full view of the type, which may be unconstrained.
1063 This may be a reference to a type, for example in the prefix of the
1064 attribute Position, generated for dispatching code (see Make_DT in
1065 exp_disp,adb). In that case we need the type itself, not is parent,
1066 in particular if it is a derived type */
1073 {
1076 }
1077 else
1078 {
1079 /* We want to use the Actual_Subtype if it has already been elaborated,
1080 otherwise the Etype. Avoid using Actual_Subtype for packed arrays to
1081 simplify things. */
1089 else
1091 }
1093 /* Expand the type of this identifier first, in case it is an enumeral
1094 literal, which only get made when the type is expanded. There is no
1095 order-of-elaboration issue here. */
1098 /* If this is a non-imported elementary constant with an address clause,
1099 retrieve the value instead of a pointer to be dereferenced unless
1100 an lvalue is required. This is generally more efficient and actually
1101 required if this is a static expression because it might be used
1102 in a context where a dereference is inappropriate, such as a case
1103 statement alternative or a record discriminant. There is no possible
1104 volatile-ness short-circuit here since Volatile constants must be
1105 imported per C.6. */
1110 {
1114 }
1117 {
1118 /* If this is a deferred constant, the initializer is attached to
1119 the full view. */
1124 }
1125 else
1128 /* Some objects (such as parameters passed by reference, globals of
1129 variable size, and renamed objects) actually represent the address
1130 of the object. In that case, we must do the dereference. Likewise,
1131 deal with parameters to foreign convention subprograms. */
1136 {
1139 /* If it's a PARM_DECL to foreign convention subprogram, convert it. */
1142 gnu_result
1145 /* If it's a CONST_DECL, return the underlying constant like below. */
1152 /* If it's a renaming pointer and, either the renamed object is constant
1153 or we are at the right binding level, we can reference the renamed
1154 object directly, since it is constant or has been protected against
1155 multiple evaluations. */
1164 /* Otherwise, do the final dereference. */
1165 else
1166 {
1176 }
1177 }
1179 /* If we have a constant declaration and its initializer, try to return the
1180 latter to avoid the need to call fold in lots of places and the need for
1181 elaboration code if this identifier is used as an initializer itself. */
1183 {
1189 /* If there is a (corresponding) variable or this is the address of a
1190 constant, we only want to return the initializer if an lvalue isn't
1191 required. Evaluate this now if we have not already done so. */
1193 require_lvalue
1197 /* Finally retrieve the initializer if this is deemed valid. */
1200 }
1202 /* But for a constant renaming we couldn't do that incrementally for its
1203 definition because of the need to return an lvalue so, if the present
1204 context doesn't itself require an lvalue, we try again here. */
1208 {
1210 require_lvalue
1215 }
1217 /* The GNAT tree has the type of a function set to its result type, so we
1218 adjust here. Also use the type of the result if the Etype is a subtype
1219 that is nominally unconstrained. Likewise if this is a deferred constant
1220 of a discriminated type whose full view can be elaborated statically, to
1221 avoid problematic conversions to the nominal subtype. But remove any
1222 padding from the resulting type. */
1229 {
1233 }
1238 }
1239 \f
1240 /* Subroutine of gnat_to_gnu to process gnat_node, an N_Pragma. Return
1241 any statements we generate. */
1243 static tree
1245 {
1248 Node_Id gnat_temp;
1250 /* Do nothing if we are just annotating types and check for (and ignore)
1251 unrecognized pragmas. */
1258 {
1260 /* Do nothing at top level: all such variables are already viewable. */
1267 {
1271 machine_mode mode;
1273 #ifdef ASM_COMMENT_START
1275 #endif
1280 /* Use the value only if it fits into a normal register,
1281 otherwise use the address. */
1290 #ifdef ASM_COMMENT_START
1296 NULL);
1299 #endif
1301 asm_constraint,
1302 NULL_TREE,
1303 tree_cons
1311 }
1318 {
1322 {
1345 }
1346 }
1352 {
1370 }
1380 {
1381 Node_Id gnat_expr;
1382 /* Preserve the location of the pragma. */
1386 diagnostic_t kind;
1391 /* This is the String form: pragma Warning{s|_As_Error}(String). */
1393 {
1395 {
1408 }
1411 }
1413 /* This is the On/Off form: pragma Warnings (On | Off [,String]). */
1415 {
1417 {
1428 }
1430 /* Deal with optional pattern (but ignore Reason => "..."). */
1432 {
1433 /* pragma Warnings (On | Off, Name) is handled differently. */
1438 }
1439 else
1443 }
1445 else
1448 /* This is the same implementation as in the C family of compilers. */
1450 {
1458 option_index++)
1462 {
1465 }
1466 }
1467 else
1474 }
1479 }
1482 }
1483 \f
1484 /* Return an expression for the length of TYPE, an integral type, computed in
1485 RESULT_TYPE, another integral type.
1487 We used to compute the length as MAX (hb - lb + 1, 0) which could overflow
1488 when lb == TYPE'First. We now compute it as (hb >= lb) ? hb - lb + 1 : 0
1489 which would only overflow in much rarer cases, for extremely large arrays
1490 we expect never to encounter in practice. Besides, the former computation
1491 required the use of potentially constraining signed arithmetics while the
1492 latter does not. Note that the comparison must be done in the original
1493 base index type in order to avoid any overflow during the conversion. */
1495 static tree
1497 {
1502 tree length
1508 length
1514 }
1516 /* Subroutine of gnat_to_gnu to translate GNAT_NODE, an N_Attribute node,
1517 to a GCC tree, which is returned. GNU_RESULT_TYPE_P is a pointer to
1518 where we should place the result type. ATTRIBUTE is the attribute ID. */
1520 static tree
1522 {
1528 /* ??? If this is an access attribute for a public subprogram to be used in
1529 a dispatch table, do not translate its type as it's useless there and the
1530 parameter types might be incomplete types coming from a limited with. */
1538 else
1542 /* If the input is a NULL_EXPR, make a new one. */
1544 {
1548 }
1551 {
1554 /* These are just conversions since representation clauses for
1555 enumeration types are handled in the front-end. */
1556 {
1562 }
1567 /* These just add or subtract the constant 1 since representation
1568 clauses for enumeration types are handled in the front-end. */
1573 {
1575 gnu_expr
1576 = emit_check
1578 gnu_expr,
1579 attribute == Attr_Pred
1583 }
1585 gnu_result
1593 /* Conversions don't change addresses but can cause us to miss the
1594 COMPONENT_REF case below, so strip them off. */
1598 /* If we are taking 'Address of an unconstrained object, this is the
1599 pointer to the underlying array. */
1603 /* If we are building a static dispatch table, we have to honor
1604 TARGET_VTABLE_USES_DESCRIPTORS if we want to be compatible
1605 with the C++ ABI. We do it in the non-static case as well,
1606 see gnat_to_gnu_entity, case E_Access_Subprogram_Type. */
1609 {
1611 /* Descriptors can only be built here for top-level functions. */
1619 /* If we're not going to build the descriptor, we have to retrieve
1620 the one which will be built by the linker (or by the compiler
1621 later if a static chain is requested). */
1623 {
1626 gnu_result);
1628 }
1635 {
1637 {
1641 }
1642 else
1648 elt--;
1649 }
1653 }
1655 /* ... fall through ... */
1661 gnu_result
1668 /* For 'Code_Address, find an inner ADDR_EXPR and mark it so that we
1669 don't try to build a trampoline. */
1671 {
1676 }
1678 /* For 'Access, issue an error message if the prefix is a C++ method
1679 since it can use a special calling convention on some platforms,
1680 which cannot be propagated to the access type. */
1685 gnat_node);
1687 /* For other address attributes applied to a nested function,
1688 find an inner ADDR_EXPR and annotate it so that we can issue
1689 a useful warning with -Wtrampolines. */
1691 {
1696 {
1699 /* Check that we're not violating the No_Implicit_Dynamic_Code
1700 restriction. Be conservative if we don't know anything
1701 about the trampoline strategy for the target. */
1703 }
1704 }
1708 {
1710 tree gnu_obj_type;
1714 /* If this is fat pointer, the object must have been allocated with the
1715 template in front of the array. So compute the template address; do
1716 it by converting to a thin pointer. */
1718 gnu_ptr
1720 (TYPE_OBJECT_RECORD_TYPE
1722 gnu_ptr);
1726 /* If this is a thin pointer, the object must have been allocated with
1727 the template in front of the array. So compute the template address
1728 and return it. */
1730 gnu_ptr
1732 gnu_ptr,
1734 byte_position
1735 (DECL_CHAIN
1739 }
1748 /* Remove NOPs and conversions between original and packable version
1749 from GNU_EXPR, and conversions from GNU_PREFIX. We use GNU_EXPR
1750 to see if a COMPONENT_REF was involved. */
1755 == RECORD_TYPE
1764 /* Replace an unconstrained array type with the type of the underlying
1765 array. We can't do this with a call to maybe_unconstrained_array
1766 since we may have a TYPE_DECL. For 'Max_Size_In_Storage_Elements,
1767 use the record type that will be used to allocate the object and its
1768 template. */
1770 {
1774 }
1776 /* If we're looking for the size of a field, return the field size. */
1780 /* Otherwise, if the prefix is an object, or if we are looking for
1781 'Object_Size or 'Max_Size_In_Storage_Elements, the result is the
1782 GCC size of the type. We make an exception for padded objects,
1783 as we do not take into account alignment promotions for the size.
1784 This is in keeping with the object case of gnat_to_gnu_entity. */
1790 {
1791 /* If this is a dereference and we have a special dynamic constrained
1792 subtype on the prefix, use it to compute the size; otherwise, use
1793 the designated subtype. */
1795 {
1796 Node_Id gnat_actual_subtype
1798 tree gnu_ptr_type
1803 {
1804 tree gnu_actual_obj_type
1806 gnu_type
1808 gnu_actual_obj_type,
1811 }
1812 }
1815 }
1817 /* Otherwise, the result is the RM size of the type. */
1818 else
1821 /* Deal with a self-referential size by returning the maximum size for
1822 a type and by qualifying the size with the object otherwise. */
1824 {
1827 else
1829 }
1831 /* If the type contains a template, subtract its size. */
1837 /* For 'Max_Size_In_Storage_Elements, adjust the unit. */
1845 {
1858 else
1859 {
1864 /* If the default alignment of "double" or larger scalar types is
1865 specifically capped and there is an alignment clause neither
1866 on the type nor on the prefix itself, return the cap. */
1868 is_capped_double
1871 is_capped_double
1873 else
1883 else
1885 }
1888 }
1897 {
1904 else
1907 }
1909 /* ... fall through ... */
1912 {
1920 /* Make sure any implicit dereference gets done. */
1924 /* We treat unconstrained array In parameters specially. We also note
1925 whether we are dereferencing a pointer to unconstrained array. */
1928 {
1930 /* This is the direct case. */
1936 /* This is the indirect case. Note that we need to be sure that
1937 the access value cannot be null as we'll hoist the load. */
1940 {
1943 }
1944 else
1950 }
1952 /* If the prefix is the view conversion of a constrained array to an
1953 unconstrained form, we retrieve the constrained array because we
1954 might not be able to substitute the PLACEHOLDER_EXPR coming from
1955 the conversion. This can occur with the 'Old attribute applied
1956 to a parameter with an unconstrained type, which gets rewritten
1957 into a constrained local variable very late in the game. */
1960 && !CONTAINS_PLACEHOLDER_P
1963 else
1970 {
1972 tree gnu_type_temp;
1978 ;
1981 }
1988 /* When not optimizing, look up the slot associated with the parameter
1989 and the dimension in the cache and create a new one on failure.
1990 Don't do this when the actual subtype needs debug info (this happens
1991 with -gnatD): in elaborate_expression_1, we create variables that
1992 hold the bounds, so caching attributes isn't very interesting and
1993 causes dependency issues between these variables and cached
1994 expressions. */
1999 {
2005 {
2010 }
2011 }
2013 /* Return the cached expression or build a new one. */
2015 {
2017 {
2020 }
2022 gnu_result
2024 }
2027 {
2029 {
2032 }
2034 gnu_result
2036 }
2039 {
2041 {
2044 }
2046 gnu_result
2048 gnu_result_type);
2049 }
2051 /* If this has a PLACEHOLDER_EXPR, qualify it by the object we are
2052 handling. Note that these attributes could not have been used on
2053 an unconstrained array type. */
2056 /* Cache the expression we have just computed. Since we want to do it
2057 at run time, we force the use of a SAVE_EXPR and let the gimplifier
2058 create the temporary in the outermost binding level. We will make
2059 sure in Subprogram_Body_to_gnu that it is evaluated on all possible
2060 paths by forcing its evaluation on entry of the function. */
2062 {
2063 gnu_result
2066 {
2082 }
2083 }
2085 /* Otherwise, evaluate it each time it is referenced. */
2086 else
2088 {
2091 /* If we are dereferencing a pointer to unconstrained array, we
2092 need to capture the value because the pointed-to bounds may
2093 subsequently be released. */
2095 gnu_result
2101 /* Set the source location onto the predicate of the condition
2102 but not if the expression is cached to avoid messing up the
2103 debug info. */
2107 gnat_node);
2112 }
2115 }
2122 {
2123 HOST_WIDE_INT bitsize;
2124 HOST_WIDE_INT bitpos;
2125 tree gnu_offset;
2126 tree gnu_field_bitpos;
2127 tree gnu_field_offset;
2128 tree gnu_inner;
2129 machine_mode mode;
2136 /* We can have 'Bit on any object, but if it isn't a COMPONENT_REF,
2137 the result is 0. Don't allow 'Bit on a bare component, though. */
2141 {
2144 }
2146 else
2155 {
2163 {
2164 gnu_field_bitpos
2167 gnu_field_offset
2170 }
2171 }
2173 {
2176 }
2177 else
2178 {
2181 }
2184 {
2198 /* ??? Avoid a large unsigned result that will overflow when
2199 converted to the signed universal_integer. */
2202 else
2203 gnu_result
2210 }
2212 /* If this has a PLACEHOLDER_EXPR, qualify it by the object we are
2213 handling. */
2216 }
2220 {
2228 }
2254 /* Note this size cannot be self-referential. */
2264 /* What we want is the offset of the ARRAY field in the record
2265 that the thin pointer designates. */
2273 /* This is just a zero cast to the pointer type for our prefix and
2274 dereferenced. */
2276 gnu_result
2279 integer_zero_node));
2284 {
2291 {
2296 ;
2297 }
2305 && (DECL_BY_COMPONENT_PTR_P
2309 }
2313 /* We treat Model as identical to Machine. This is true for at least
2314 IEEE and some other nice floating-point systems. */
2316 /* ... fall through ... */
2319 /* The trick is to force the compiler to store the result in memory so
2320 that we do not have extra precision used. But do this only when this
2321 is necessary, i.e. if FP_ARITH_MAY_WIDEN is true and the precision of
2322 the type is lower than that of the longest floating-point type. */
2331 {
2333 tree field
2343 asm_expr
2355 gnu_result
2359 }
2363 /* This abort means that we have an unimplemented attribute. */
2365 }
2367 /* If this is an attribute where the prefix was unused, force a use of it if
2368 it has a side-effect. But don't do it if the prefix is just an entity
2369 name. However, if an access check is needed, we must do it. See second
2370 example in AARM 11.6(5.e). */
2374 gnu_result
2379 }
2380 \f
2381 /* Subroutine of gnat_to_gnu to translate gnat_node, an N_Case_Statement,
2382 to a GCC tree, which is returned. */
2384 static tree
2386 {
2388 Node_Id gnat_when;
2389 location_t end_locus;
2395 /* The range of values in a case statement is determined by the rules in
2396 RM 5.4(7-9). In almost all cases, this range is represented by the Etype
2397 of the expression. One exception arises in the case of a simple name that
2398 is parenthesized. This still has the Etype of the name, but since it is
2399 not a name, para 7 does not apply, and we need to go to the base type.
2400 This is the only case where parenthesization affects the dynamic
2401 semantics (i.e. the range of possible values at run time that is covered
2402 by the others alternative).
2404 Another exception is if the subtype of the expression is non-static. In
2405 that case, we also have to use the base type. */
2411 /* We build a SWITCH_EXPR that contains the code with interspersed
2412 CASE_LABEL_EXPRs for each label. */
2421 {
2423 Node_Id gnat_choice;
2425 /* First compile all the different case choices for the current WHEN
2426 alternative. */
2430 {
2435 {
2450 /* This represents either a subtype range or a static value of
2451 some kind; Ekind says which. */
2453 {
2459 }
2461 /* ... fall through ... */
2473 }
2475 /* Everything should be folded into constants at this point. */
2480 gnat_choice);
2482 }
2484 /* This construct doesn't define a scope so we shouldn't push a binding
2485 level around the statement list. Except that we have always done so
2486 historically and this makes it possible to reduce stack usage. As a
2487 compromise, we keep doing it for case statements, for which this has
2488 never been problematic, but not for case expressions in Ada 2012. */
2490 {
2491 const bool is_case_expression
2493 tree group
2498 {
2503 }
2504 }
2505 }
2507 /* Now emit a definition of the label the cases branch to, if any. */
2514 }
2515 \f
2516 /* Find out whether VAR is an iteration variable of an enclosing loop in the
2517 current function. If so, push a range_check_info structure onto the stack
2518 of this enclosing loop and return it. Otherwise, return NULL. */
2522 {
2539 i--)
2544 {
2548 }
2551 }
2553 /* Return true if VAL (of type TYPE) can equal the minimum value if MAX is
2554 false, or the maximum value if MAX is true, of TYPE. */
2556 static bool
2558 {
2565 val = (max
2574 else
2576 }
2578 /* Return true if VAL (of type TYPE) can equal the minimum value of TYPE.
2579 If REVERSE is true, minimum value is taken as maximum value. */
2583 {
2585 }
2587 /* Return true if VAL (of type TYPE) can equal the maximum value of TYPE.
2588 If REVERSE is true, maximum value is taken as minimum value. */
2592 {
2594 }
2596 /* Return true if VAL1 can be lower than VAL2. */
2598 static bool
2600 {
2614 }
2616 /* Subroutine of gnat_to_gnu to translate gnat_node, an N_Loop_Statement,
2617 to a GCC tree, which is returned. */
2619 static tree
2621 {
2628 tree gnu_result;
2630 /* Push the loop_info structure associated with the LOOP_STMT. */
2633 /* Set location information for statement and end label. */
2639 /* Save the statement for later reuse. */
2642 /* Set the condition under which the loop must keep going.
2643 For the case "LOOP .... END LOOP;" the condition is always true. */
2645 ;
2647 /* For the case "WHILE condition LOOP ..... END LOOP;" it's immediate. */
2652 /* Otherwise we have an iteration scheme and the condition is given by the
2653 bounds of the subtype of the iteration variable. */
2654 else
2655 {
2669 /* We must disable modulo reduction for the iteration variable, if any,
2670 in order for the loop comparison to be effective. */
2672 {
2678 }
2679 else
2680 {
2686 }
2688 /* We use two different strategies to translate the loop, depending on
2689 whether optimization is enabled.
2691 If it is, we generate the canonical loop form expected by the loop
2692 optimizer and the loop vectorizer, which is the do-while form:
2694 ENTRY_COND
2695 loop:
2696 TOP_UPDATE
2697 BODY
2698 BOTTOM_COND
2699 GOTO loop
2701 This avoids an implicit dependency on loop header copying and makes
2702 it possible to turn BOTTOM_COND into an inequality test.
2704 If optimization is disabled, loop header copying doesn't come into
2705 play and we try to generate the loop form with the fewer conditional
2706 branches. First, the default form, which is:
2708 loop:
2709 TOP_COND
2710 BODY
2711 BOTTOM_UPDATE
2712 GOTO loop
2714 It should catch most loops with constant ending point. Then, if we
2715 cannot, we try to generate the shifted form:
2717 loop:
2718 TOP_COND
2719 TOP_UPDATE
2720 BODY
2721 GOTO loop
2723 which should catch loops with constant starting point. Otherwise, if
2724 we cannot, we generate the fallback form:
2726 ENTRY_COND
2727 loop:
2728 BODY
2729 BOTTOM_COND
2730 BOTTOM_UPDATE
2731 GOTO loop
2733 which works in all cases. */
2736 {
2737 /* We can use the do-while form directly if GNU_FIRST-1 doesn't
2738 overflow. */
2740 ;
2742 /* Otherwise, use the do-while form with the help of a special
2743 induction variable in the unsigned version of the base type
2744 or the unsigned version of the size type, whichever is the
2745 largest, in order to have wrap-around arithmetics for it. */
2746 else
2747 {
2750 gnu_base_type
2752 else
2759 }
2761 gnu_first
2763 gnu_one_node);
2766 }
2767 else
2768 {
2769 /* We can use the default form if GNU_LAST+1 doesn't overflow. */
2771 ;
2773 /* Otherwise, we can use the shifted form if neither GNU_FIRST-1 nor
2774 GNU_LAST-1 does. */
2777 {
2778 gnu_first
2780 gnu_one_node);
2781 gnu_last
2783 gnu_one_node);
2785 }
2787 /* Otherwise, use the fallback form. */
2788 else
2790 }
2792 /* If we use the BOTTOM_COND, we can turn the test into an inequality
2793 test but we may have to add ENTRY_COND to protect the empty loop. */
2795 {
2798 {
2799 gnu_cond_expr
2805 }
2806 }
2808 /* Open a new nesting level that will surround the loop to declare the
2809 iteration variable. */
2813 /* If we use the special induction variable, create it and set it to
2814 its initial value. Morever, the regular iteration variable cannot
2815 itself be initialized, lest the initial value wrapped around. */
2817 {
2818 gnu_loop_iv
2822 }
2823 else
2826 /* Declare the iteration variable and set it to its initial value. */
2831 {
2834 }
2837 /* Do all the arithmetics in the base type. */
2840 /* Set either the top or bottom exit condition. */
2844 gnu_last);
2845 else
2848 gnu_last);
2850 /* Set either the top or bottom update statement and give it the source
2851 location of the iteration for better coverage info. */
2853 {
2854 gnu_stmt
2861 gnu_stmt
2863 gnu_loop_iv);
2867 }
2868 else
2869 {
2870 gnu_stmt
2876 }
2877 }
2879 /* If the loop was named, have the name point to this loop. In this case,
2880 the association is not a DECL node, but the end label of the loop. */
2884 /* Make the loop body into its own block, so any allocated storage will be
2885 released every iteration. This is needed for stack allocation. */
2890 /* If we have an iteration scheme, then we are in a statement group. Add
2891 the LOOP_STMT to it, finish it and make it the "loop". */
2893 {
2898 /* First, if we have computed a small number of invariant conditions for
2899 range checks applied to the iteration variable, then initialize these
2900 conditions in front of the loop. Otherwise, leave them set to true.
2902 ??? The heuristics need to be improved, by taking into account the
2903 following datapoints:
2904 - loop unswitching is disabled for big loops. The cap is the
2905 parameter PARAM_MAX_UNSWITCH_INSNS (50).
2906 - loop unswitching can only be applied a small number of times
2907 to a given loop. The cap is PARAM_MAX_UNSWITCH_LEVEL (3).
2908 - the front-end quickly generates useless or redundant checks
2909 that can be entirely optimized away in the end. */
2913 i++)
2914 {
2915 tree low_ok
2922 tree high_ok
2929 tree range_ok
2937 }
2942 }
2944 /* If we have an outer COND_EXPR, that's our result and this loop is its
2945 "true" statement. Otherwise, the result is the LOOP_STMT. */
2947 {
2951 }
2952 else
2958 }
2959 \f
2960 /* This page implements a form of Named Return Value optimization modelled
2961 on the C++ optimization of the same name. The main difference is that
2962 we disregard any semantical considerations when applying it here, the
2963 counterpart being that we don't try to apply it to semantically loaded
2964 return types, i.e. types with the TYPE_BY_REFERENCE_P flag set.
2966 We consider a function body of the following GENERIC form:
2968 return_type R1;
2969 [...]
2970 RETURN_EXPR [<retval> = ...]
2971 [...]
2972 RETURN_EXPR [<retval> = R1]
2973 [...]
2974 return_type Ri;
2975 [...]
2976 RETURN_EXPR [<retval> = ...]
2977 [...]
2978 RETURN_EXPR [<retval> = Ri]
2979 [...]
2981 and we try to fulfill a simple criterion that would make it possible to
2982 replace one or several Ri variables with the RESULT_DECL of the function.
2984 The first observation is that RETURN_EXPRs that don't directly reference
2985 any of the Ri variables on the RHS of their assignment are transparent wrt
2986 the optimization. This is because the Ri variables aren't addressable so
2987 any transformation applied to them doesn't affect the RHS; moreover, the
2988 assignment writes the full <retval> object so existing values are entirely
2989 discarded.
2991 This property can be extended to some forms of RETURN_EXPRs that reference
2992 the Ri variables, for example CONSTRUCTORs, but isn't true in the general
2993 case, in particular when function calls are involved.
2995 Therefore the algorithm is as follows:
2997 1. Collect the list of candidates for a Named Return Value (Ri variables
2998 on the RHS of assignments of RETURN_EXPRs) as well as the list of the
2999 other expressions on the RHS of such assignments.
3001 2. Prune the members of the first list (candidates) that are referenced
3002 by a member of the second list (expressions).
3004 3. Extract a set of candidates with non-overlapping live ranges from the
3005 first list. These are the Named Return Values.
3007 4. Adjust the relevant RETURN_EXPRs and replace the occurrences of the
3008 Named Return Values in the function with the RESULT_DECL.
3010 If the function returns an unconstrained type, things are a bit different
3011 because the anonymous return object is allocated on the secondary stack
3012 and RESULT_DECL is only a pointer to it. Each return object can be of a
3013 different size and is allocated separately so we need not care about the
3014 aforementioned overlapping issues. Therefore, we don't collect the other
3015 expressions and skip step #2 in the algorithm. */
3017 struct nrv_data
3018 {
3019 bitmap nrv;
3020 tree result;
3021 Node_Id gnat_ret;
3023 };
3025 /* Return true if T is a Named Return Value. */
3029 {
3031 }
3033 /* Helper function for walk_tree, used by finalize_nrv below. */
3035 static tree
3037 {
3041 /* No need to walk into types or decls. */
3049 }
3051 /* Prune Named Return Values in BLOCK and return true if there is still a
3052 Named Return Value in BLOCK or one of its sub-blocks. */
3054 static bool
3056 {
3058 tree t;
3060 /* First recurse on the sub-blocks. */
3064 /* Then make sure to keep at most one NRV per block. */
3067 {
3070 else
3072 }
3075 }
3077 /* Helper function for walk_tree, used by finalize_nrv below. */
3079 static tree
3081 {
3085 /* No need to walk into types. */
3089 /* Change RETURN_EXPRs of NRVs to just refer to the RESULT_DECL; this is a
3090 nop, but differs from using NULL_TREE in that it indicates that we care
3091 about the value of the RESULT_DECL. */
3094 {
3097 /* If this is the temporary created for a return value with variable
3098 size in Call_to_gnu, we replace the RHS with the init expression. */
3103 {
3106 }
3107 else
3110 /* Strip useless conversions around the return value. */
3115 {
3118 else
3120 }
3121 }
3123 /* Replace the DECL_EXPR of NRVs with an initialization of the RESULT_DECL,
3124 if needed. */
3127 {
3131 {
3136 }
3137 else
3141 /* Identify the NRV to the RESULT_DECL for debugging purposes. */
3144 /* ??? Kludge to avoid an assertion failure during inlining. */
3147 }
3149 /* And replace all uses of NRVs with the RESULT_DECL. */
3153 /* Avoid walking into the same tree more than once. Unfortunately, we
3154 can't just use walk_tree_without_duplicates because it would only
3155 call us for the first occurrence of NRVs in the function body. */
3160 }
3162 /* Likewise, but used when the function returns an unconstrained type. */
3164 static tree
3166 {
3170 /* No need to walk into types. */
3174 /* We need to see the DECL_EXPR of NRVs before any other references so we
3175 walk the body of BIND_EXPR before walking its variables. */
3179 /* Change RETURN_EXPRs of NRVs to assign to the RESULT_DECL only the final
3180 return value built by the allocator instead of the whole construct. */
3183 {
3186 /* This is the construct returned by the allocator. */
3189 {
3191 ret_val
3194 else
3196 }
3198 /* Strip useless conversions around the return value. */
3203 /* Strip unpadding around the return value. */
3208 /* Assign the new return value to the RESULT_DECL. */
3212 }
3214 /* Adjust the DECL_EXPR of NRVs to call the allocator and save the result
3215 into a new variable. */
3218 {
3225 /* Create an artificial context to build the allocation. */
3230 /* This will return a COMPOUND_EXPR with the allocation in the first
3231 arm and the final return value in the second arm. */
3238 /* The new variable is built as a reference to the allocated space. */
3239 new_var
3245 {
3246 /* The new initial value is a COMPOUND_EXPR with the allocation in
3247 the first arm and the value of P_ARRAY in the second arm. */
3253 /* Build a modified CONSTRUCTOR that references NEW_VAR. */
3261 }
3262 else
3263 {
3264 /* The new initial value is just the allocation. */
3267 }
3271 /* Destroy the artificial context and insert the new statements. */
3276 /* Chain NEW_VAR immediately after VAR and ignore the latter. */
3281 /* Save the new return value and the dereference of NEW_VAR. */
3285 /* ??? Kludge to avoid messing up during inlining. */
3287 }
3289 /* And replace all uses of NRVs with the dereference of NEW_VAR. */
3293 /* Avoid walking into the same tree more than once. Unfortunately, we
3294 can't just use walk_tree_without_duplicates because it would only
3295 call us for the first occurrence of NRVs in the function body. */
3300 }
3302 /* Finalize the Named Return Value optimization for FNDECL. The NRV bitmap
3303 contains the candidates for Named Return Value and OTHER is a list of
3304 the other return values. GNAT_RET is a representative return node. */
3306 static void
3308 {
3311 walk_tree_fn func;
3313 tree iter;
3315 /* We shouldn't be applying the optimization to return types that we aren't
3316 allowed to manipulate freely. */
3319 /* Prune the candidates that are referenced by other return values. */
3328 /* Prune also the candidates that are referenced by nested functions. */
3336 /* Extract a set of NRVs with non-overlapping live ranges. */
3340 /* Adjust the relevant RETURN_EXPRs and replace the occurrences of NRVs. */
3347 else
3351 }
3353 /* Return true if RET_VAL can be used as a Named Return Value for the
3354 anonymous return object RET_OBJ. */
3356 static bool
3358 {
3378 }
3380 /* Build a RETURN_EXPR. If RET_VAL is non-null, build a RETURN_EXPR around
3381 the assignment of RET_VAL to RET_OBJ. Otherwise build a bare RETURN_EXPR
3382 around RESULT_OBJ, which may be null in this case. */
3384 static tree
3386 {
3387 tree result_expr;
3390 {
3391 /* The gimplifier explicitly enforces the following invariant:
3393 RETURN_EXPR
3394 |
3395 MODIFY_EXPR
3396 / \
3397 / \
3398 RET_OBJ ...
3400 As a consequence, type consistency dictates that we use the type
3401 of the RET_OBJ as the operation type. */
3404 /* Convert the right operand to the operation type. Note that it's the
3405 same transformation as in the MODIFY_EXPR case of build_binary_op,
3406 with the assumption that the type cannot involve a placeholder. */
3412 /* If the function returns an aggregate type, find out whether this is
3413 a candidate for Named Return Value. If so, record it. Otherwise,
3414 if this is an expression of some kind, record it elsewhere. */
3420 {
3421 /* Recognize the temporary created for a return value with variable
3422 size in Call_to_gnu. We want to eliminate it if possible. */
3429 /* Strip useless conversions around the return value. */
3433 /* Now apply the test to the return value. */
3435 {
3439 }
3441 /* Note that we need not care about CONSTRUCTORs here, as they are
3442 totally transparent given the read-compose-write semantics of
3443 assignments from CONSTRUCTORs. */
3446 }
3447 }
3448 else
3452 }
3453 \f
3454 /* Subroutine of gnat_to_gnu to process gnat_node, an N_Subprogram_Body. We
3455 don't return anything. */
3457 static void
3459 {
3460 /* Defining identifier of a parameter to the subprogram. */
3461 Entity_Id gnat_param;
3462 /* The defining identifier for the subprogram body. Note that if a
3463 specification has appeared before for this body, then the identifier
3464 occurring in that specification will also be a defining identifier and all
3465 the calls to this subprogram will point to that specification. */
3466 Entity_Id gnat_subprog_id
3469 /* The FUNCTION_DECL node corresponding to the subprogram spec. */
3470 tree gnu_subprog_decl;
3471 /* Its RESULT_DECL node. */
3472 tree gnu_result_decl;
3473 /* Its FUNCTION_TYPE node. */
3474 tree gnu_subprog_type;
3475 /* The TYPE_CI_CO_LIST of its FUNCTION_TYPE node, if any. */
3476 tree gnu_cico_list;
3477 /* The entry in the CI_CO_LIST that represents a function return, if any. */
3479 tree gnu_result;
3480 location_t locus;
3484 /* If this is a generic object or if it has been eliminated,
3485 ignore it. */
3491 /* If this subprogram acts as its own spec, define it. Otherwise, just get
3492 the already-elaborated tree node. However, if this subprogram had its
3493 elaboration deferred, we will already have made a tree node for it. So
3494 treat it as not being defined in that case. Such a subprogram cannot
3495 have an address clause or a freeze node, so this test is safe, though it
3496 does disable some otherwise-useful error checking. */
3497 gnu_subprog_decl
3507 /* If the function returns by invisible reference, make it explicit in the
3508 function body. See gnat_to_gnu_entity, E_Subprogram_Type case.
3509 Handle the explicit case here and the copy-in/copy-out case below. */
3511 {
3515 }
3517 /* Set the line number in the decl to correspond to that of the body. */
3521 /* Initialize the information structure for the function. */
3530 /* If there are In Out or Out parameters, we need to ensure that the return
3531 statement properly copies them out. We do this by making a new block and
3532 converting any return into a goto to a label at the end of the block. */
3534 {
3543 /* If this is a function with In Out or Out parameters, we also need a
3544 variable for the return value to be placed. */
3546 {
3547 tree gnu_return_type
3550 /* If the function returns by invisible reference, make it
3551 explicit in the function body. See gnat_to_gnu_entity,
3552 E_Subprogram_Type case. */
3556 gnu_return_var
3561 }
3565 /* See whether there are parameters for which we don't have a GCC tree
3566 yet. These must be Out parameters. Make a VAR_DECL for them and
3567 put it into TYPE_CI_CO_LIST, which must contain an empty entry too.
3568 We can match up the entries because TYPE_CI_CO_LIST is in the order
3569 of the parameters. */
3574 {
3576 tree gnu_decl;
3578 /* Skip any entries that have been already filled in; they must
3579 correspond to In Out parameters. */
3583 /* Do any needed dereferences for by-ref objects. */
3589 /* Do any needed references for padded types. */
3592 }
3593 }
3594 else
3597 /* Get a tree corresponding to the code for the subprogram. */
3603 /* Generate the code of the subprogram itself. A return statement will be
3604 present and any Out parameters will be handled there. */
3609 /* If we populated the parameter attributes cache, we need to make sure that
3610 the cached expressions are evaluated on all the possible paths leading to
3611 their uses. So we force their evaluation on entry of the function. */
3614 {
3621 {
3628 }
3634 }
3636 /* If we are dealing with a return from an Ada procedure with parameters
3637 passed by copy-in/copy-out, we need to return a record containing the
3638 final values of these parameters. If the list contains only one entry,
3639 return just that entry though.
3641 For a full description of the copy-in/copy-out parameter mechanism, see
3642 the part of the gnat_to_gnu_entity routine dealing with the translation
3643 of subprograms.
3645 We need to make a block that contains the definition of that label and
3646 the copying of the return value. It first contains the function, then
3647 the label and copy statement. */
3649 {
3650 tree gnu_retval;
3660 else
3662 gnu_cico_list);
3668 }
3672 /* Attempt setting the end_locus of our GCC body tree, typically a
3673 BIND_EXPR or STATEMENT_LIST, then the end_locus of our GCC subprogram
3674 declaration tree. */
3678 /* On SEH targets, install an exception handler around the main entry
3679 point to catch unhandled exceptions. */
3682 {
3683 tree t;
3684 tree etype;
3696 }
3700 /* Finally annotate the parameters and disconnect the trees for parameters
3701 that we have turned into variables since they are now unusable. */
3705 {
3714 }
3716 /* Disconnect the variable created for the return value. */
3720 /* If the function returns an aggregate type and we have candidates for
3721 a Named Return Value, finalize the optimization. */
3723 {
3730 }
3733 }
3734 \f
3735 /* Return true if GNAT_NODE requires atomic synchronization. */
3737 static bool
3739 {
3741 Node_Kind kind;
3744 /* First, scan the node to find the Atomic_Sync_Required flag. */
3747 {
3750 }
3753 {
3765 }
3767 /* Then, scan the parent to find out cases where the flag is irrelevant. */
3770 {
3773 /* Do not mess up machine code insertions. */
3779 /* Do not generate a function call as a renamed object. */
3784 }
3787 }
3788 \f
3789 /* Create a temporary variable with PREFIX and TYPE, and return it. */
3791 static tree
3793 {
3801 }
3803 /* Create a temporary variable with PREFIX and initialize it with GNU_INIT.
3804 Put the initialization statement into GNU_INIT_STMT and annotate it with
3805 the SLOC of GNAT_NODE. Return the temporary variable. */
3807 static tree
3809 Node_Id gnat_node)
3810 {
3817 }
3819 /* Subroutine of gnat_to_gnu to translate gnat_node, either an N_Function_Call
3820 or an N_Procedure_Call_Statement, to a GCC tree, which is returned.
3821 GNU_RESULT_TYPE_P is a pointer to where we should place the result type.
3822 If GNU_TARGET is non-null, this must be a function call on the RHS of a
3823 N_Assignment_Statement and the result is to be placed into that object.
3824 If, in addition, ATOMIC_SYNC is true, then the assignment to GNU_TARGET
3825 requires atomic synchronization. */
3827 static tree
3830 {
3833 /* The GCC node corresponding to the GNAT subprogram name. This can either
3834 be a FUNCTION_DECL node if we are dealing with a standard subprogram call,
3835 or an indirect reference expression (an INDIRECT_REF node) pointing to a
3836 subprogram. */
3838 /* The FUNCTION_TYPE node giving the GCC type of the subprogram. */
3840 /* The return type of the FUNCTION_TYPE. */
3851 Entity_Id gnat_formal;
3852 Node_Id gnat_actual;
3856 /* If we are calling a stubbed function, raise Program_Error, but Elaborate
3857 all our args first. */
3859 {
3869 {
3872 }
3875 }
3877 /* The only way we can be making a call via an access type is if Name is an
3878 explicit dereference. In that case, get the list of formal args from the
3879 type the access type is pointing to. Otherwise, get the formals from the
3880 entity being called. */
3884 /* Assume here that this must be 'Elab_Body or 'Elab_Spec. */
3886 else
3889 /* The lifetime of the temporaries created for the call ends right after the
3890 return value is copied, so we can give them the scope of the elaboration
3891 routine at top level. */
3893 {
3896 }
3898 /* First, create the temporary for the return value when:
3900 1. There is no target and the function has copy-in/copy-out parameters,
3901 because we need to preserve the return value before copying back the
3902 parameters.
3904 2. There is no target and this is not an object declaration, and the
3905 return type has variable size, because in these cases the gimplifier
3906 cannot create the temporary.
3908 3. There is a target and it is a slice or an array with fixed size,
3909 and the return type has variable size, because the gimplifier
3910 doesn't handle these cases.
3912 This must be done before we push a binding level around the call, since
3913 we will pop it before copying the return value. */
3916 || (!gnu_target
3919 || (gnu_target
3927 /* Create the list of the actual parameters as GCC expects it, namely a
3928 chain of TREE_LIST nodes in which the TREE_VALUE field of each node
3929 is an expression and the TREE_PURPOSE field is null. But skip Out
3930 parameters not passed by reference and that need not be copied in. */
3935 {
3939 const bool is_true_formal_parm
3941 const bool is_by_ref_formal_parm
3942 = is_true_formal_parm
3945 /* In the Out or In Out case, we must suppress conversions that yield
3946 an lvalue but can nevertheless cause the creation of a temporary,
3947 because we need the real object in this case, either to pass its
3948 address if it's passed by reference or as target of the back copy
3949 done after the call if it uses the copy-in/copy-out mechanism.
3950 We do it in the In case too, except for an unchecked conversion
3951 because it alone can cause the actual to be misaligned and the
3952 addressability test is applied to the real object. */
3953 const bool suppress_type_conversion
3958 Node_Id gnat_name = suppress_type_conversion
3961 tree gnu_actual;
3963 /* If it's possible we may need to use this expression twice, make sure
3964 that any side-effects are handled via SAVE_EXPRs; likewise if we need
3965 to force side-effects before the call.
3966 ??? This is more conservative than we need since we don't need to do
3967 this for pass-by-ref with no conversion. */
3971 /* If we are passing a non-addressable parameter by reference, pass the
3972 address of a copy. In the Out or In Out case, set up to copy back
3973 out after the call. */
3977 {
3981 /* Do not issue warnings for CONSTRUCTORs since this is not a copy
3982 but sort of an instantiation for them. */
3984 ;
3986 /* If the type is passed by reference, a copy is not allowed. */
3989 gnat_actual);
3991 /* For users of Starlet we issue a warning because the interface
3992 apparently assumes that by-ref parameters outlive the procedure
3993 invocation. The code still will not work as intended, but we
3994 cannot do much better since low-level parts of the back-end
3995 would allocate temporaries at will because of the misalignment
3996 if we did not do so here. */
3998 {
3999 post_error
4001 post_error_ne
4005 gnat_formal);
4006 }
4008 /* If the actual type of the object is already the nominal type,
4009 we have nothing to do, except if the size is self-referential
4010 in which case we'll remove the unpadding below. */
4013 ;
4015 /* Otherwise remove the unpadding from all the objects. */
4017 && TYPE_IS_PADDING_P
4021 /* Otherwise convert to the nominal type of the object if needed.
4022 There are several cases in which we need to make the temporary
4023 using this type instead of the actual type of the object when
4024 they are distinct, because the expectations of the callee would
4025 otherwise not be met:
4026 - if it's a justified modular type,
4027 - if the actual type is a smaller form of it,
4028 - if it's a smaller form of the actual type. */
4032 gnu_name_type)))
4038 /* If this is an In Out or Out parameter and we're returning a value,
4039 we need to create a temporary for the return value because we must
4040 preserve it before copying back at the very end. */
4044 /* If we haven't pushed a binding level, push a new one. This will
4045 narrow the lifetime of the temporary we are about to make as much
4046 as possible. The drawback is that we'd need to create a temporary
4047 for the return value, if any (see comment before the loop). So do
4048 it only when this temporary was already created just above. */
4050 {
4054 }
4056 /* Create an explicit temporary holding the copy. */
4057 gnu_temp
4060 /* But initialize it on the fly like for an implicit temporary as
4061 we aren't necessarily having a statement list. */
4063 gnu_temp);
4065 /* Set up to move the copy back to the original if needed. */
4067 {
4068 /* If the original is a COND_EXPR whose first arm isn't meant to
4069 be further used, just deal with the second arm. This is very
4070 likely the conditional expression built for a check. */
4073 && integer_zerop
4077 gnu_stmt
4082 }
4083 }
4085 /* Start from the real object and build the actual. */
4088 /* If this is an atomic access of an In or In Out parameter for which
4089 synchronization is required, build the atomic load. */
4091 && !is_by_ref_formal_parm
4096 /* If this was a procedure call, we may not have removed any padding.
4097 So do it here for the part we will use as an input, if any. */
4100 gnu_actual
4103 /* Put back the conversion we suppressed above in the computation of the
4104 real object. And even if we didn't suppress any conversion there, we
4105 may have suppressed a conversion to the Etype of the actual earlier,
4106 since the parent is a procedure call, so put it back here. */
4109 gnu_actual
4112 else
4113 gnu_actual
4116 /* Make sure that the actual is in range of the formal's type. */
4119 gnu_actual
4122 /* Unless this is an In parameter, we must remove any justified modular
4123 building from GNU_NAME to get an lvalue. */
4128 gnu_name
4131 /* First see if the parameter is passed by reference. */
4133 {
4135 {
4136 /* In Out or Out parameters passed by reference don't use the
4137 copy-in/copy-out mechanism so the address of the real object
4138 must be passed to the function. */
4141 /* If we have a padded type, be sure we've removed padding. */
4144 gnu_actual);
4146 /* If we have the constructed subtype of an aliased object
4147 with an unconstrained nominal subtype, the type of the
4148 actual includes the template, although it is formally
4149 constrained. So we need to convert it back to the real
4150 constructed subtype to retrieve the constrained part
4151 and takes its address. */
4157 gnu_actual);
4158 }
4160 /* There is no need to convert the actual to the formal's type before
4161 taking its address. The only exception is for unconstrained array
4162 types because of the way we build fat pointers. */
4164 {
4165 /* Put back a view conversion for In Out or Out parameters. */
4168 gnu_actual);
4170 }
4172 /* The symmetry of the paths to the type of an entity is broken here
4173 since arguments don't know that they will be passed by ref. */
4176 }
4178 /* Then see if the parameter is an array passed to a foreign convention
4179 subprogram. */
4181 {
4187 {
4190 }
4192 /* Take the address of the object and convert to the proper pointer
4193 type. We'd like to actually compute the address of the beginning
4194 of the array using an ADDR_EXPR of an ARRAY_REF, but there's a
4195 possibility that the ARRAY_REF might return a constant and we'd be
4196 getting the wrong address. Neither approach is exactly correct,
4197 but this is the most likely to work in all cases. */
4199 }
4201 /* Otherwise the parameter is passed by copy. */
4202 else
4203 {
4204 tree gnu_size;
4209 /* If we didn't create a PARM_DECL for the formal, this means that
4210 it is an Out parameter not passed by reference and that need not
4211 be copied in. In this case, the value of the actual need not be
4212 read. However, we still need to make sure that its side-effects
4213 are evaluated before the call, so we evaluate its address. */
4215 {
4217 {
4220 }
4222 }
4226 /* If this is 'Null_Parameter, pass a zero even though we are
4227 dereferencing it. */
4233 gnu_actual
4237 integer_zero_node),
4239 else
4241 }
4244 }
4246 gnu_call
4250 /* If we have created a temporary for the return value, initialize it. */
4252 {
4253 tree gnu_stmt
4258 }
4260 /* If this is a subprogram with copy-in/copy-out parameters, we need to
4261 unpack the valued returned from the function into the In Out or Out
4262 parameters. We deal with the function return (if this is an Ada
4263 function) below. */
4265 {
4266 /* List of FIELD_DECLs associated with the PARM_DECLs of the copy-in/
4267 copy-out parameters. */
4271 /* The call sequence must contain one and only one call, even though the
4272 function is pure. Save the result into a temporary if needed. */
4274 {
4276 {
4277 tree gnu_stmt;
4278 /* If we haven't pushed a binding level, push a new one. This
4279 will narrow the lifetime of the temporary we are about to
4280 make as much as possible. */
4282 {
4286 }
4287 gnu_call
4290 }
4293 }
4295 /* The first entry is for the actual return value if this is a
4296 function, so skip it. */
4302 else
4309 /* If we are dealing with a copy-in/copy-out parameter, we must
4310 retrieve its value from the record returned in the call. */
4316 {
4317 /* Get the value to assign to this Out or In Out parameter. It is
4318 either the result of the function if there is only a single such
4319 parameter or the appropriate field from the record returned. */
4320 tree gnu_result
4322 ? gnu_call
4326 /* If the actual is a conversion, get the inner expression, which
4327 will be the real destination, and convert the result to the
4328 type of the actual parameter. */
4329 tree gnu_actual
4332 /* If the result is a padded type, remove the padding. */
4334 gnu_result
4336 gnu_result);
4338 /* If the actual is a type conversion, the real target object is
4339 denoted by the inner Expression and we need to convert the
4340 result to the associated type.
4341 We also need to convert our gnu assignment target to this type
4342 if the corresponding GNU_NAME was constructed from the GNAT
4343 conversion node and not from the inner Expression. */
4345 {
4346 gnu_result
4347 = convert_with_check
4355 }
4357 /* Unchecked conversions as actuals for Out parameters are not
4358 allowed in user code because they are not variables, but do
4359 occur in front-end expansions. The associated GNU_NAME is
4360 always obtained from the inner expression in such cases. */
4363 gnu_result,
4365 else
4366 {
4368 gnu_result
4370 gnat_actual);
4375 }
4379 else
4386 }
4387 }
4389 /* If this is a function call, the result is the call expression unless a
4390 target is specified, in which case we copy the result into the target
4391 and return the assignment statement. */
4393 {
4394 /* If this is a function with copy-in/copy-out parameters, extract the
4395 return value from it and update the return type. */
4397 {
4402 }
4404 /* If the function returns an unconstrained array or by direct reference,
4405 we have to dereference the pointer. */
4411 {
4415 /* If range check is needed, emit code to generate it. */
4417 gnu_call
4419 gnat_parent);
4421 /* ??? If the return type has variable size, then force the return
4422 slot optimization as we would not be able to create a temporary.
4423 Likewise if it was unconstrained as we would copy too much data.
4424 That's what has been done historically. */
4427 && CONTAINS_PLACEHOLDER_P
4430 else
4435 else
4436 gnu_call
4440 }
4441 else
4443 }
4445 /* Otherwise, if this is a procedure call statement without copy-in/copy-out
4446 parameters, the result is just the call statement. */
4450 /* Finally, add the copy back statements, if any. */
4456 /* If we have pushed a binding level, pop it and finish up the enclosing
4457 statement group. */
4459 {
4463 }
4465 /* Otherwise, retrieve the statement list, if any. */
4469 /* Otherwise, just return the call expression. */
4470 else
4473 /* If we nevertheless need a value, make a COMPOUND_EXPR to return it.
4474 But first simplify if we have only one statement in the list. */
4476 {
4480 gnu_result
4482 }
4485 }
4486 \f
4487 /* Subroutine of gnat_to_gnu to translate gnat_node, an
4488 N_Handled_Sequence_Of_Statements, to a GCC tree, which is returned. */
4490 static tree
4492 {
4495 /* If just annotating, ignore all EH and cleanups. */
4499 bool setjmp_longjmp
4505 tree gnu_result;
4506 tree gnu_expr;
4507 Node_Id gnat_temp;
4508 /* Node providing the sloc for the cleanup actions. */
4511 gnat_node);
4513 /* The GCC exception handling mechanism can handle both ZCX and SJLJ schemes
4514 and we have our own SJLJ mechanism. To call the GCC mechanism, we call
4515 add_cleanup, and when we leave the binding, end_stmt_group will create
4516 the TRY_FINALLY_EXPR.
4518 ??? The region level calls down there have been specifically put in place
4519 for a ZCX context and currently the order in which things are emitted
4520 (region/handlers) is different from the SJLJ case. Instead of putting
4521 other calls with different conditions at other places for the SJLJ case,
4522 it seems cleaner to reorder things for the SJLJ case and generalize the
4523 condition to make it not ZCX specific.
4525 If there are any exceptions or cleanup processing involved, we need an
4526 outer statement group (for Setjmp_Longjmp) and binding level. */
4528 {
4531 }
4533 /* If using setjmp_longjmp, make the variables for the setjmp buffer and save
4534 area for address of previous buffer. Do this first since we need to have
4535 the setjmp buf known for any decls in this block. */
4537 {
4538 gnu_jmpsave_decl
4540 jmpbuf_ptr_type,
4545 /* The __builtin_setjmp receivers will immediately reinstall it. Now
4546 because of the unstructured form of EH used by setjmp_longjmp, there
4547 might be forward edges going to __builtin_setjmp receivers on which
4548 it is uninitialized, although they will never be actually taken. */
4550 gnu_jmpbuf_decl
4552 jmpbuf_type,
4553 NULL_TREE,
4559 /* When we exit this block, restore the saved value. */
4561 gnat_cleanup_loc_node);
4562 }
4564 /* If we are to call a function when exiting this block, add a cleanup
4565 to the binding level we made above. Note that add_cleanup is FIFO
4566 so we must register this cleanup after the EH cleanup just above. */
4569 gnat_cleanup_loc_node);
4571 /* Now build the tree for the declarations and statements inside this block.
4572 If this is SJLJ, set our jmp_buf as the current buffer. */
4578 gnu_jmpbuf_decl)));
4584 /* Generate code for each statement in the block. */
4592 /* Now generate code for the two exception models, if either is relevant for
4593 this block. */
4595 {
4597 tree gnu_handler;
4599 /* Make a binding level for the exception handling declarations and code
4600 and set up gnu_except_ptr_stack for the handlers to use. */
4611 /* Generate code for each handler. The N_Exception_Handler case does the
4612 real work and returns a COND_EXPR for each handler, which we chain
4613 together here. */
4616 {
4619 /* If this is the first one, set it as the outer one. Otherwise,
4620 point the "else" part of the previous handler to us. Then point
4621 to our "else" part. */
4624 else
4628 }
4630 /* If none of the exception handlers did anything, re-raise but do not
4631 defer abortion. */
4634 set_expr_location_from_node
4640 else
4643 /* End the binding level dedicated to the exception handlers and get the
4644 whole statement group. */
4649 /* If the setjmp returns 1, we restore our incoming longjmp value and
4650 then check the handlers. */
4653 gnu_jmpsave_decl),
4654 gnat_node);
4658 /* This block is now "if (setjmp) ... <handlers> else <block>". */
4660 (build_call_n_expr
4663 gnu_jmpbuf_decl))),
4665 }
4667 {
4668 tree gnu_handlers;
4669 location_t locus;
4671 /* First make a block containing the handlers. */
4679 /* Now make the TRY_CATCH_EXPR for the block. */
4682 /* Set a location. We need to find a unique location for the dispatching
4683 code, otherwise we can get coverage or debugging issues. Try with
4684 the location of the end label. */
4688 else
4689 /* Clear column information so that the exception handler of an
4690 implicit transient block does not incorrectly inherit the slocs
4691 of a decision, which would otherwise confuse control flow based
4692 coverage analysis tools. */
4694 }
4695 else
4698 /* Now close our outer block, if we had to make one. */
4700 {
4704 }
4707 }
4708 \f
4709 /* Subroutine of gnat_to_gnu to translate gnat_node, an N_Exception_Handler,
4710 to a GCC tree, which is returned. This is the variant for Setjmp_Longjmp
4711 exception handling. */
4713 static tree
4715 {
4716 /* Unless this is "Others" or the special "Non-Ada" exception for Ada, make
4717 an "if" statement to select the proper exceptions. For "Others", exclude
4718 exceptions where Handled_By_Others is nonzero unless the All_Others flag
4719 is set. For "Non-ada", accept an exception if "Lang" is 'V'. */
4722 Node_Id gnat_temp;
4726 {
4727 tree this_choice;
4730 {
4733 else
4734 this_choice
4735 = build_binary_op
4737 convert
4739 build_component_ref
4740 (build_unary_op
4745 integer_zero_node);
4746 }
4750 {
4752 tree gnu_expr;
4754 /* Exception may be a renaming. Recover original exception which is
4755 the one elaborated and registered. */
4761 this_choice
4762 = build_binary_op
4767 }
4768 else
4773 }
4776 }
4777 \f
4778 /* Subroutine of gnat_to_gnu to translate gnat_node, an N_Exception_Handler,
4779 to a GCC tree, which is returned. This is the variant for ZCX. */
4781 static tree
4783 {
4786 Node_Id gnat_temp;
4788 /* We build a TREE_LIST of nodes representing what exception types this
4789 handler can catch, with special cases for others and all others cases.
4791 Each exception type is actually identified by a pointer to the exception
4792 id, or to a dummy object for "others" and "all others". */
4795 {
4799 {
4802 }
4805 {
4808 /* Exception may be a renaming. Recover original exception which is
4809 the one elaborated and registered. */
4815 }
4816 else
4819 /* The GCC interface expects NULL to be passed for catch all handlers, so
4820 it would be quite tempting to set gnu_etypes_list to NULL if gnu_etype
4821 is integer_zero_node. It would not work, however, because GCC's
4822 notion of "catch all" is stronger than our notion of "others". Until
4823 we correctly use the cleanup interface as well, doing that would
4824 prevent the "all others" handlers from being seen, because nothing
4825 can be caught beyond a catch all from GCC's point of view. */
4827 }
4832 /* Expand a call to the begin_handler hook at the beginning of the handler,
4833 and arrange for a call to the end_handler hook to occur on every possible
4834 exit path.
4836 The hooks expect a pointer to the low level occurrence. This is required
4837 for our stack management scheme because a raise inside the handler pushes
4838 a new occurrence on top of the stack, which means that this top does not
4839 necessarily match the occurrence this handler was dealing with.
4841 __builtin_eh_pointer references the exception occurrence being
4842 propagated. Upon handler entry, this is the exception for which the
4843 handler is triggered. This might not be the case upon handler exit,
4844 however, as we might have a new occurrence propagated by the handler's
4845 body, and the end_handler hook called as a cleanup in this context.
4847 We use a local variable to retrieve the incoming value at handler entry
4848 time, and reuse it to feed the end_handler hook's argument at exit. */
4850 gnu_current_exc_ptr
4860 gnu_incoming_exc_ptr),
4861 gnat_node);
4863 /* Declare and initialize the choice parameter, if present. */
4865 {
4866 tree gnu_param
4872 gnu_incoming_exc_ptr));
4873 }
4875 /* We don't have an End_Label at hand to set the location of the cleanup
4876 actions, so we use that of the exception handler itself instead. */
4878 gnat_node);
4884 return
4886 }
4887 \f
4888 /* Subroutine of gnat_to_gnu to generate code for an N_Compilation unit. */
4890 static void
4892 {
4897 Entity_Id gnat_entity;
4898 Node_Id gnat_pragma;
4899 /* Make the decl for the elaboration procedure. */
4900 tree gnu_elab_proc_decl
4901 = create_subprog_decl
4904 gnat_unit);
4910 /* Initialize the information structure for the function. */
4919 /* For a body, first process the spec if there is one. */
4925 {
4932 }
4934 /* Then process any pragmas and declarations preceding the unit. */
4943 /* Process the unit itself. */
4946 /* Generate code for all the inlined subprograms. */
4950 {
4951 Node_Id gnat_body;
4953 /* Without optimization, process only the required subprograms. */
4959 {
4960 /* ??? This happens when only the spec of a package is provided. */
4964 gnat_body
4966 }
4968 /* Define the entity first so we set DECL_EXTERNAL. */
4971 }
4973 /* Process any pragmas and actions following the unit. */
4978 /* Save away what we've made so far and record this potential elaboration
4979 procedure. */
4992 /* Generate elaboration code for this unit, if necessary, and say whether
4993 we did or not. */
4996 /* Invalidate the global renaming pointers. This is necessary because
4997 stabilization of the renamed entities may create SAVE_EXPRs which
4998 have been tied to a specific elaboration routine just above. */
5001 /* Force the processing for all nodes that remain in the queue. */
5003 }
5004 \f
5005 /* Subroutine of gnat_to_gnu to translate gnat_node, an N_Raise_xxx_Error,
5006 to a GCC tree, which is returned. GNU_RESULT_TYPE_P is a pointer to where
5007 we should place the result type. LABEL_P is true if there is a label to
5008 branch to for the exception. */
5010 static tree
5012 {
5016 const bool with_extra_info
5017 = Exception_Extra_Info
5025 {
5035 {
5041 {
5061 }
5068 && gnu_low_bound
5069 && gnu_high_bound
5072 gnu_result
5076 /* If loop unswitching is enabled, we try to compute invariant
5077 conditions for checks applied to iteration variables, i.e.
5078 conditions that are both independent of the variable and
5079 necessary in order for the check to fail in the course of
5080 some iteration, and prepend them to the original condition
5081 of the checks. This will make it possible later for the
5082 loop unswitching pass to replace the loop with two loops,
5083 one of which has the checks eliminated and the other has
5084 the original checks reinstated, and a run time selection.
5085 The former loop will be suitable for vectorization. */
5087 && (!gnu_low_bound
5089 && (!gnu_high_bound
5092 {
5097 boolean_true_node);
5099 boolean_type_node,
5102 }
5103 }
5108 }
5110 common:
5115 /* If the type is VOID, this is a statement, so we need to generate the code
5116 for the call. Handle a condition, if there is one. */
5118 {
5120 {
5125 }
5126 }
5127 else
5131 }
5132 \f
5133 /* Return true if GNAT_NODE is on the LHS of an assignment or an actual
5134 parameter of a call. */
5136 static bool
5138 {
5153 }
5155 /* Return true if either GNAT_NODE or a view of GNAT_NODE is on the LHS
5156 of an assignment or an actual parameter of a call. */
5158 static bool
5160 {
5161 Node_Kind kind;
5173 }
5175 /* Return true if GNAT_NODE, an unchecked type conversion, is a no-op as far
5176 as gigi is concerned. This is used to avoid conversions on the LHS. */
5178 static bool
5180 {
5183 /* The conversion must be on the LHS of an assignment or an actual parameter
5184 of a call. Otherwise, even if the conversion was essentially a no-op, it
5185 could de facto ensure type consistency and this should be preserved. */
5191 /* We're interested in artificial conversions generated by the front-end
5192 to make private types explicit, e.g. in Expand_Assign_Array. */
5199 /* The direct conversion to the underlying type is a no-op. */
5203 /* For an array subtype, the conversion to the PAIT is a no-op. */
5208 /* For a record subtype, the conversion to the type is a no-op. */
5214 }
5216 /* This function is the driver of the GNAT to GCC tree transformation process.
5217 It is the entry point of the tree transformer. GNAT_NODE is the root of
5218 some GNAT tree. Return the root of the corresponding GCC tree. If this
5219 is an expression, return the GCC equivalent of the expression. If this
5220 is a statement, return the statement or add it to the current statement
5221 group, in which case anything returned is to be interpreted as occurring
5222 after anything added. */
5224 tree
5226 {
5232 Node_Id gnat_temp;
5234 /* Save node number for error message and set location information. */
5238 /* If this node is a statement and we are only annotating types, return an
5239 empty statement list. */
5243 /* If this node is a non-static subexpression and we are only annotating
5244 types, make this into a NULL_EXPR. */
5251 N_Raise_Constraint_Error));
5260 {
5263 /* If this is a statement and we are at top level, it must be part of
5264 the elaboration procedure, so mark us as being in that procedure. */
5266 {
5269 }
5271 /* If we are in the elaboration procedure, check if we are violating a
5272 No_Elaboration_Code restriction by having a statement there. Don't
5273 check for a possible No_Elaboration_Code restriction violation on
5274 N_Handled_Sequence_Of_Statements, as we want to signal an error on
5275 every nested real statement instead. This also avoids triggering
5276 spurious errors on dummy (empty) sequences created by the front-end
5277 for package bodies in some cases. */
5281 }
5284 {
5285 /********************************/
5286 /* Chapter 2: Lexical Elements */
5287 /********************************/
5295 /* If this is an atomic access on the RHS for which synchronization is
5296 required, build the atomic load. */
5303 {
5304 tree gnu_type;
5306 /* Get the type of the result, looking inside any padding and
5307 justified modular types. Then get the value in that type. */
5316 /* If the result overflows (meaning it doesn't fit in its base type),
5317 abort. We would like to check that the value is within the range
5318 of the subtype, but that causes problems with subtypes whose usage
5319 will raise Constraint_Error and with biased representation, so
5320 we don't. */
5322 }
5326 /* If a Entity is present, it means that this was one of the
5327 literals in a user-defined character type. In that case,
5328 just return the value in the CONST_DECL. Otherwise, use the
5329 character code. In that case, the base type should be an
5330 INTEGER_TYPE, but we won't bother checking for that. */
5334 else
5335 gnu_result
5336 = build_int_cst_type
5343 /* If this is of a fixed-point type, the value we want is the value of
5344 the corresponding integer. */
5346 {
5348 gnu_result_type);
5350 }
5352 else
5353 {
5356 /* First convert the value to a machine number if it isn't already.
5357 That will force the base to 2 for non-zero values and simplify
5358 the rest of the logic. */
5360 ur_realval
5366 else
5367 {
5368 REAL_VALUE_TYPE tmp;
5372 /* The base must be 2 as Machine guarantees this, so we scale
5373 the value, which we know can fit in the mantissa of the type
5374 (hence the use of that type above). */
5379 }
5381 /* Now see if we need to negate the result. Do it this way to
5382 properly handle -0. */
5384 gnu_result
5386 gnu_result);
5387 }
5394 {
5401 else
5404 /* Build the string with the characters in the literal. Note
5405 that Ada strings are 1-origin. */
5409 /* Put a null at the end of the string in case it's in a context
5410 where GCC will want to treat it as a C string. */
5415 /* Strings in GCC don't normally have types, but we want
5416 this to not be converted to the array type. */
5421 }
5422 else
5423 {
5424 /* Build a list consisting of each character, then make
5425 the aggregate. */
5435 {
5441 }
5444 }
5451 /**************************************/
5452 /* Chapter 3: Declarations and Types */
5453 /**************************************/
5470 /* If we are just annotating types and this object has an unconstrained
5471 or task type, don't elaborate it. */
5481 && (!type_annotate_only
5483 {
5486 gnu_expr
5489 /* If this object has its elaboration delayed, we must force
5490 evaluation of GNU_EXPR right now and save it for when the object
5491 is frozen. */
5493 {
5495 ;
5497 gnu_expr
5502 else
5506 }
5507 }
5508 else
5514 /* If this is a deferred constant with an address clause, we ignore the
5515 full view since the clause is on the partial view and we cannot have
5516 2 different GCC trees for the object. The only bits of the full view
5517 we will use is the initializer, but it will be directly fetched. */
5530 /* Don't do anything if this renaming is handled by the front end or if
5531 we are just annotating types and this object has a composite or task
5532 type, don't elaborate it. We return the result in case it has any
5533 SAVE_EXPRs in it that need to be evaluated here. */
5535 && ! (type_annotate_only
5539 gnu_result
5542 else
5549 gnu_result
5552 else
5564 /* These are fully handled in the front end. */
5565 /* ??? For package renamings, find a way to use GENERIC namespaces so
5566 that we get proper debug information for them. */
5570 /*************************************/
5571 /* Chapter 4: Names and Expressions */
5572 /*************************************/
5579 /* If this is an atomic access on the RHS for which synchronization is
5580 required, build the atomic load. */
5587 {
5589 tree gnu_type;
5596 /* Convert vector inputs to their representative array type, to fit
5597 what the code below expects. */
5599 {
5603 }
5607 /* If we got a padded type, remove it too. */
5609 gnu_array_object
5611 gnu_array_object);
5615 /* The failure of this assertion will very likely come from a missing
5616 expansion for a packed array access. */
5619 /* First compute the number of dimensions of the array, then
5620 fill the expression array, the order depending on whether
5621 this is a Convention_Fortran array or not. */
5626 ;
5635 else
5643 {
5649 gnu_expr
5650 = emit_index_check
5654 gnat_temp);
5656 gnu_result
5659 /* Array accesses are bound-checked so they cannot trap, but this
5660 is valid only if they are not hoisted ahead of the check. We
5661 need to mark them as no-trap to get decent loop optimizations
5662 in the presence of -fnon-call-exceptions, so we do it when we
5663 know that the original expression had no side-effects. */
5668 }
5672 /* If this is an atomic access on the RHS for which synchronization is
5673 required, build the atomic load. */
5677 }
5681 {
5683 tree gnu_type;
5688 /* Do any implicit dereferences of the prefix and do any needed
5689 range check. */
5694 {
5695 /* Get the bounds of the slice. */
5696 tree gnu_index_type
5700 /* Get the permitted bounds. */
5701 tree gnu_base_index_type
5703 tree gnu_base_min_expr = SUBSTITUTE_PLACEHOLDER_IN_EXPR
5705 tree gnu_base_max_expr = SUBSTITUTE_PLACEHOLDER_IN_EXPR
5712 /* Derive a good type to convert everything to. */
5715 /* Test whether the minimum slice value is too small. */
5718 gnu_min_expr),
5720 gnu_base_min_expr));
5722 /* Test whether the maximum slice value is too large. */
5725 gnu_max_expr),
5727 gnu_base_max_expr));
5729 /* Build a slice index check that returns the low bound,
5730 assuming the slice is not empty. */
5731 gnu_expr = emit_check
5736 /* Build a conditional expression that does the index checks and
5737 returns the low bound if the slice is not empty (max >= min),
5738 and returns the naked low bound otherwise (max < min), unless
5739 it is non-constant and the high bound is; this prevents VRP
5740 from inferring bogus ranges on the unlikely path. */
5744 gnu_max_expr),
5746 gnu_min_expr)),
5747 gnu_expr,
5751 }
5752 else
5753 /* Simply return the naked low bound. */
5756 /* If this is a slice with non-constant size of an array with constant
5757 size, set the maximum size for the allocation of temporaries. */
5764 }
5768 {
5772 tree gnu_field;
5776 /* For discriminant references in tagged types always substitute the
5777 corresponding discriminant as the actual selected component. */
5782 /* For discriminant references of untagged types always substitute the
5783 corresponding stored discriminant. */
5787 /* Handle extracting the real or imaginary part of a complex.
5788 The real part is the first field and the imaginary the last. */
5793 else
5794 {
5797 /* If there are discriminants, the prefix might be evaluated more
5798 than once, which is a problem if it has side-effects. */
5805 gnu_result
5809 && lvalue_required_for_attribute_p
5811 }
5815 /* If this is an atomic access on the RHS for which synchronization is
5816 required, build the atomic load. */
5820 }
5824 {
5825 /* The attribute designator. */
5828 /* The Elab_Spec and Elab_Body attributes are special in that Prefix
5829 is a unit, not an object with a GCC equivalent. */
5831 return
5839 }
5843 /* Like 'Access as far as we are concerned. */
5851 {
5852 tree gnu_aggr_type;
5854 /* ??? It is wrong to evaluate the type now, but there doesn't
5855 seem to be any other practical way of doing it. */
5859 gnu_aggr_type = gnu_result_type
5864 gnu_aggr_type
5871 NULL);
5875 gnu_result
5878 gnu_aggr_type);
5881 gnu_aggr_type,
5884 gnu_result
5885 = build_binary_op
5890 (Next
5892 else
5896 }
5904 else
5911 /* Get the operand expression. */
5915 /* If this is a qualified expression for a tagged type, we mark the type
5916 as used. Because of polymorphism, this might be the only reference to
5917 the tagged type in the program while objects have it as dynamic type.
5918 The debugger needs to see it to display these objects properly. */
5922 gnu_result
5926 kind == N_Type_Conversion
5933 /* Skip further processing if the conversion is deemed a no-op. */
5935 {
5938 }
5942 /* If the result is a pointer type, see if we are improperly
5943 converting to a stricter alignment. */
5946 {
5952 post_error_ne_tree_2
5956 }
5958 /* If we are converting a descriptor to a function pointer, first
5959 build the pointer. */
5971 {
5976 /* GNAT_RANGE is either an N_Range node or an identifier denoting a
5977 subtype. */
5979 {
5982 }
5985 {
5989 gnu_low
5991 gnu_high
5993 }
5994 else
5999 /* If LOW and HIGH are identical, perform an equality test. Otherwise,
6000 ensure that GNU_OBJ is evaluated only once and perform a full range
6001 test. */
6003 gnu_result
6005 else
6006 {
6015 gnu_result
6017 }
6020 gnu_result
6022 }
6030 ? RDIV_EXPR
6037 /* These can either be operations on booleans or on modular types.
6038 Fall through for boolean types since that's the way GNU_CODES is
6039 set up. */
6041 {
6042 enum tree_code code
6053 }
6055 /* ... fall through ... */
6067 {
6071 tree gnu_type;
6077 /* Pending generic support for efficient vector logical operations in
6078 GCC, convert vectors to their representative array type view and
6079 fallthrough. */
6083 /* If this is a comparison operator, convert any references to an
6084 unconstrained array value into a reference to the actual array. */
6086 {
6089 }
6091 /* If this is a shift whose count is not guaranteed to be correct,
6092 we need to adjust the shift count. */
6094 {
6096 tree gnu_max_shift
6103 gnu_rhs
6104 = build_binary_op
6107 gnu_count_type,
6108 gnu_max_shift,
6110 integer_one_node)),
6111 gnu_rhs);
6112 }
6114 /* For right shifts, the type says what kind of shift to do,
6115 so we may need to choose a different type. In this case,
6116 we have to ignore integer overflow lest it propagates all
6117 the way down and causes a CE to be explicitly raised. */
6119 {
6122 }
6125 {
6128 }
6131 {
6137 }
6139 /* Instead of expanding overflow checks for addition, subtraction
6140 and multiplication itself, the front end will leave this to
6141 the back end when Backend_Overflow_Checks_On_Target is set.
6142 As the GCC back end itself does not know yet how to properly
6143 do overflow checking, do it here. The goal is to push
6144 the expansions further into the back end over time. */
6153 else
6154 {
6155 /* Some operations, e.g. comparisons of arrays, generate complex
6156 trees that need to be annotated while they are being built. */
6159 }
6161 /* If this is a logical shift with the shift count not verified,
6162 we must return zero if it is too large. We cannot compensate
6163 above in this case. */
6166 gnu_result
6167 = build_cond_expr
6170 gnu_rhs,
6174 gnu_result);
6175 }
6179 {
6182 tree gnu_false
6186 gnu_result
6188 }
6197 /* This case can apply to a boolean or a modular type.
6198 Fall through for a boolean operand since GNU_CODES is set
6199 up to handle this. */
6201 {
6205 gnu_expr);
6207 }
6209 /* ... fall through ... */
6218 gnu_result
6221 else
6227 {
6229 tree gnu_type;
6234 /* The Expression operand can either be an N_Identifier or
6235 Expanded_Name, which must represent a type, or a
6236 N_Qualified_Expression, which contains both the object type and an
6237 initial value for the object. */
6242 {
6243 Entity_Id gnat_desig_type
6251 gnu_init
6257 else
6258 {
6262 }
6264 /* See the N_Qualified_Expression case for the rationale. */
6269 }
6270 else
6277 ignore_init_type);
6278 }
6281 /**************************/
6282 /* Chapter 5: Statements */
6283 /**************************/
6291 /* When not optimizing, turn null statements from source into gotos to
6292 the next statement that the middle-end knows how to preserve. */
6294 {
6305 }
6306 else
6311 /* Get the LHS and RHS of the statement and convert any reference to an
6312 unconstrained array into a reference to the underlying array. */
6315 /* If the type has a size that overflows, convert this into raise of
6316 Storage_Error: execution shouldn't have gotten here anyway. */
6320 N_Raise_Storage_Error);
6322 gnu_result
6325 else
6326 {
6328 const Entity_Id gnat_type
6330 const bool regular_array_type_p
6332 const bool use_memset_p
6333 = (regular_array_type_p
6337 /* If we'll use memset, we need to find the inner expression. */
6339 {
6340 Node_Id gnat_inner
6344 gnat_inner
6347 }
6348 else
6351 /* If range check is needed, emit code to generate it. */
6354 gnat_node);
6356 /* If atomic synchronization is required, build an atomic store. */
6360 /* Or else, use memset when the conditions are met. */
6362 {
6366 tree size
6371 {
6372 tree mask
6376 }
6378 }
6380 /* Otherwise build a regular assignment. */
6381 else
6382 gnu_result
6385 /* If the assignment type is a regular array and the two sides are
6386 not completely disjoint, play safe and use memmove. But don't do
6387 it for a bit-packed array as it might not be byte-aligned. */
6389 && regular_array_type_p
6391 {
6395 tree size
6401 }
6402 }
6406 {
6409 /* Make the outer COND_EXPR. Avoid non-determinism. */
6418 /* Now make a COND_EXPR for each of the "else if" parts. Put each
6419 into the previous "else" part and point to where to put any
6420 outer "else". Also avoid non-determinism. */
6424 {
6434 }
6437 }
6449 /* The only way to enter the block is to fall through to it. */
6451 {
6458 }
6459 else
6464 gnu_result
6474 {
6477 /* If the subprogram is a function, we must return the expression. */
6479 {
6482 /* If this function has copy-in/copy-out parameters, get the real
6483 object for the return. See Subprogram_to_gnu. */
6486 else
6489 /* Get the GCC tree for the expression to be returned. */
6492 /* Do not remove the padding from GNU_RET_VAL if the inner type is
6493 self-referential since we want to allocate the fixed size. */
6495 && TYPE_IS_PADDING_P
6497 && CONTAINS_PLACEHOLDER_P
6501 /* If the function returns by direct reference, return a pointer
6502 to the return value. */
6507 /* Otherwise, if it returns an unconstrained array, we have to
6508 allocate a new version of the result and return it. */
6510 {
6513 /* And find out whether this is a candidate for Named Return
6514 Value. If so, record it. */
6516 {
6519 /* Strip useless conversions around the return value. */
6523 /* Strip unpadding around the return value. */
6525 && TYPE_IS_PADDING_P
6529 /* Now apply the test to the return value. */
6531 {
6537 }
6538 }
6541 gnu_ret_val,
6546 }
6548 /* Otherwise, if it returns by invisible reference, dereference
6549 the pointer it is passed using the type of the return value
6550 and build the copy operation manually. This ensures that we
6551 don't copy too much data, for example if the return type is
6552 unconstrained with a maximum size. */
6554 {
6555 tree gnu_ret_deref
6557 gnu_ret_obj);
6562 }
6563 }
6565 else
6568 /* If we have a return label defined, convert this into a branch to
6569 that label. The return proper will be handled elsewhere. */
6571 {
6574 gnu_ret_val));
6579 /* When not optimizing, make sure the return is preserved. */
6582 }
6584 /* Otherwise, build a regular return. */
6585 else
6587 }
6591 gnu_result
6595 /***************************/
6596 /* Chapter 6: Subprograms */
6597 /***************************/
6600 /* Unless there is a freeze node, declare the subprogram. We consider
6601 this a "definition" even though we're not generating code for
6602 the subprogram because we will be making the corresponding GCC
6603 node here. */
6612 /* This subprogram doesn't exist for code generation purposes, but we
6613 have to elaborate the types of any parameters and result, unless
6614 they are imported types (nothing to generate in this case).
6616 The parameter list may contain types with freeze nodes, e.g. not null
6617 subtypes, so the subprogram itself may carry a freeze node, in which
6618 case its elaboration must be deferred. */
6620 /* Process the parameter types first. */
6623 = First_Formal_With_Extras
6631 /* Then the result type, set to Standard_Void_Type for procedures. */
6632 {
6633 Entity_Id gnat_temp_type
6638 }
6644 /* For a child unit identifier go up a level to get the specification.
6645 We get this when we try to find the spec of a child unit package
6646 that is the compilation unit being compiled. */
6660 /************************/
6661 /* Chapter 7: Packages */
6662 /************************/
6678 /* If this is the body of a generic package - do nothing. */
6680 {
6683 }
6694 /********************************/
6695 /* Chapter 8: Visibility Rules */
6696 /********************************/
6700 /* Nothing to do here - but these may appear in list of declarations. */
6704 /*********************/
6705 /* Chapter 9: Tasks */
6706 /*********************/
6717 /*********************************************************/
6718 /* Chapter 10: Program Structure and Compilation Issues */
6719 /*********************************************************/
6722 /* This is not called for the main unit on which gigi is invoked. */
6731 /* Simply process whatever unit is being inserted. */
6734 else
6735 {
6738 }
6745 /***************************/
6746 /* Chapter 11: Exceptions */
6747 /***************************/
6750 /* If there is an At_End procedure attached to this node, and the EH
6751 mechanism is SJLJ, we must have at least a corresponding At_End
6752 handler, unless the No_Exception_Handlers restriction is set. */
6767 else
6772 /* Only for reraise in back-end exceptions mode. */
6779 /* Clear the current exception pointer so that the occurrence won't be
6780 deallocated. */
6819 /******************************/
6820 /* Chapter 12: Generic Units */
6821 /******************************/
6831 /* These nodes can appear on a declaration list but there is nothing to
6832 to be done with them. */
6836 /**************************************************/
6837 /* Chapter 13: Representation Clauses and */
6838 /* Implementation-Dependent Features */
6839 /**************************************************/
6844 /* The only one we need to deal with is 'Address since, for the others,
6845 the front-end puts the information elsewhere. */
6849 /* And we only deal with 'Address if the object has a Freeze node. */
6854 /* Get the value to use as the address and save it as the equivalent
6855 for the object. When it is frozen, gnat_to_gnu_entity will do the
6856 right thing. */
6863 /* We do nothing with these. SEM puts the information elsewhere. */
6869 {
6879 /* First retrieve the 3 operand lists built by the front-end. */
6882 {
6889 }
6893 {
6900 }
6904 gnu_clobbers
6907 gnu_clobbers);
6909 /* Then perform some standard checking and processing on the
6910 operands. In particular, mark them addressable if needed. */
6918 {
6920 constraint
6926 {
6927 /* If the operand is going to end up in memory,
6928 mark it addressable. Note that we don't test
6929 allows_mem like in the input case below; this
6930 is modelled on the C front-end. */
6932 {
6939 }
6940 }
6941 else
6945 }
6948 {
6950 constraint
6956 {
6957 /* If the operand is going to end up in memory,
6958 mark it addressable. */
6960 {
6967 }
6968 }
6969 else
6973 }
6979 }
6980 else
6985 /****************/
6986 /* Added Nodes */
6987 /****************/
6990 /* This construct doesn't define a scope so we don't push a binding level
6991 around the statement list; but we wrap it in a SAVE_EXPR to protect it
6992 from unsharing. */
6997 gnu_result
7022 {
7027 /* If this is a thin pointer, we must first dereference it to create
7028 a fat pointer, then go back below to a thin pointer. The reason
7029 for this is that we need to have a fat pointer someplace in order
7030 to properly compute the size. */
7034 gnu_ptr));
7036 /* If this is a fat pointer, the object must have been allocated with
7037 the template in front of the array. So pass the template address,
7038 and get the total size; do it by converting to a thin pointer. */
7040 gnu_ptr
7042 (TYPE_OBJECT_RECORD_TYPE
7044 gnu_ptr);
7048 /* If this is a thin pointer, the object must have been allocated with
7049 the template in front of the array. So pass the template address,
7050 and get the total size. */
7052 gnu_ptr
7054 gnu_ptr,
7056 byte_position
7057 (DECL_CHAIN
7060 /* If we have a special dynamic constrained subtype on the node, use
7061 it to compute the size; otherwise, use the designated subtype. */
7063 {
7064 gnu_actual_obj_type
7068 gnu_actual_obj_type
7070 gnu_actual_obj_type,
7073 }
7074 else
7077 gnu_result
7080 gnu_obj_type,
7083 gnat_node);
7084 }
7092 else
7097 /* The only validation we currently do on an unchecked conversion is
7098 that of aliasing assumptions. */
7110 /* These nodes should only be present when annotating types. */
7116 /* Other nodes are not supposed to reach here. */
7118 }
7120 /* If we pushed the processing of the elaboration routine, pop it back. */
7124 /* When not optimizing, turn boolean rvalues B into B != false tests
7125 so that the code just below can put the location information of the
7126 reference to B on the inequality operator for better debug info. */
7140 boolean_false_node));
7142 /* Set the location information on the result. Note that we may have
7143 no result if we tried to build a CALL_EXPR node to a procedure with
7144 no side-effects and optimization is enabled. */
7148 /* If we're supposed to return something of void_type, it means we have
7149 something we're elaborating for effect, so just return. */
7153 /* If the result is a constant that overflowed, raise Constraint_Error. */
7155 {
7157 gnu_result
7160 N_Raise_Constraint_Error));
7161 }
7163 /* If the result has side-effects and is of an unconstrained type, make a
7164 SAVE_EXPR so that we can be sure it will only be referenced once. But
7165 this is useless for a call to a function that returns an unconstrained
7166 type with default discriminant, as we cannot compute the size of the
7167 actual returned object. We must do this before any conversions. */
7175 /* Now convert the result to the result type, unless we are in one of the
7176 following cases:
7178 1. If this is the LHS of an assignment or an actual parameter of a
7179 call, return the result almost unmodified since the RHS will have
7180 to be converted to our type in that case, unless the result type
7181 has a simpler size. Likewise if there is just a no-op unchecked
7182 conversion in-between. Similarly, don't convert integral types
7183 that are the operands of an unchecked conversion since we need
7184 to ignore those conversions (for 'Valid).
7186 2. If we have a label (which doesn't have any well-defined type), a
7187 field or an error, return the result almost unmodified. Similarly,
7188 if the two types are record types with the same name, don't convert.
7189 This will be the case when we are converting from a packable version
7190 of a type to its original type and we need those conversions to be
7191 NOPs in order for assignments into these types to work properly.
7193 3. If the type is void or if we have no result, return error_mark_node
7194 to show we have no result.
7196 4. If this a call to a function that returns an unconstrained type with
7197 default discriminant, return the call expression unmodified since we
7198 cannot compute the size of the actual returned object.
7200 5. Finally, if the type of the result is already correct. */
7218 && (CONTAINS_PLACEHOLDER_P
7222 {
7223 /* Remove padding only if the inner object is of self-referential
7224 size: in that case it must be an object of unconstrained type
7225 with a default discriminant and we want to avoid copying too
7226 much data. */
7231 gnu_result);
7232 }
7241 {
7242 /* Remove any padding. */
7245 gnu_result);
7246 }
7254 == gnu_result_type
7256 ;
7261 /* We don't need any NOP_EXPR or NON_LVALUE_EXPR on the result. */
7268 }
7269 \f
7270 /* Subroutine of above to push the exception label stack. GNU_STACK is
7271 a pointer to the stack to update and GNAT_LABEL, if present, is the
7272 label to push onto the stack. */
7274 static void
7276 {
7282 }
7283 \f
7284 /* Record the current code position in GNAT_NODE. */
7286 static void
7288 {
7293 }
7295 /* Insert the code for GNAT_NODE at the position saved for that node. */
7297 static void
7299 {
7302 }
7303 \f
7304 /* Start a new statement group chained to the previous group. */
7306 void
7308 {
7311 /* First see if we can get one from the free list. */
7314 else
7320 }
7322 /* Add GNU_STMT to the current statement group. If it is an expression with
7323 no effects, it is ignored. */
7325 void
7327 {
7329 }
7331 /* Similar, but the statement is always added, regardless of side-effects. */
7333 void
7335 {
7337 }
7339 /* Like add_stmt, but set the location of GNU_STMT to that of GNAT_NODE. */
7341 void
7343 {
7344 /* Do not emit a location for renamings that come from generic instantiation,
7345 they are likely to disturb debugging. */
7350 }
7352 /* Similar, but the statement is always added, regardless of side-effects. */
7354 void
7356 {
7360 }
7362 /* Add a declaration statement for GNU_DECL to the current statement group.
7363 Get SLOC from Entity_Id. */
7365 void
7367 {
7371 /* If this is a variable that Gigi is to ignore, we may have been given
7372 an ERROR_MARK. So test for it. We also might have been given a
7373 reference for a renaming. So only do something for a decl. Also
7374 ignore a TYPE_DECL for an UNCONSTRAINED_ARRAY_TYPE. */
7382 /* If we are external or global, we don't want to output the DECL_EXPR for
7383 this DECL node since we already have evaluated the expressions in the
7384 sizes and positions as globals and doing it again would be wrong. */
7386 {
7387 /* Mark everything as used to prevent node sharing with subprograms.
7388 Note that walk_tree knows how to deal with TYPE_DECL, but neither
7389 VAR_DECL nor CONST_DECL. This appears to be somewhat arbitrary. */
7393 {
7397 }
7398 /* In any case, we have to deal with our own TYPE_ADA_SIZE field. */
7403 }
7404 else
7407 /* If this is a variable and an initializer is attached to it, it must be
7408 valid for the context. Similar to init_const in create_var_decl_1. */
7415 {
7416 /* If GNU_DECL has a padded type, convert it to the unpadded
7417 type so the assignment is done properly. */
7420 else
7427 {
7430 }
7433 }
7434 }
7436 /* Callback for walk_tree to mark the visited trees rooted at *TP. */
7438 static tree
7440 {
7446 /* Don't mark a dummy type as visited because we want to mark its sizes
7447 and fields once it's filled in. */
7455 }
7457 /* Mark nodes rooted at T with TREE_VISITED and types as having their
7458 sized gimplified. We use this to indicate all variable sizes and
7459 positions in global types may not be shared by any subprogram. */
7461 void
7463 {
7465 }
7467 /* Add GNU_CLEANUP, a cleanup action, to the current code group and
7468 set its location to that of GNAT_NODE if present, but with column info
7469 cleared so that conditional branches generated as part of the cleanup
7470 code do not interfere with coverage analysis tools. */
7472 static void
7474 {
7478 }
7480 /* Set the BLOCK node corresponding to the current code group to GNU_BLOCK. */
7482 void
7484 {
7487 }
7489 /* Return code corresponding to the current code group. It is normally
7490 a STATEMENT_LIST, but may also be a BIND_EXPR or TRY_FINALLY_EXPR if
7491 BLOCK or cleanups were set. */
7493 tree
7495 {
7499 /* If this is a null list, allocate a new STATEMENT_LIST. Then, if there
7500 are cleanups, make a TRY_FINALLY_EXPR. Last, if there is a BLOCK,
7501 make a BIND_EXPR. Note that we nest in that because the cleanup may
7502 reference variables in the block. */
7514 /* Remove this group from the stack and add it to the free list. */
7520 }
7522 /* Return whether the current statement group may fall through. */
7526 {
7529 else
7531 }
7533 /* Add a list of statements from GNAT_LIST, a possibly-empty list of
7534 statements.*/
7536 static void
7538 {
7539 Node_Id gnat_node;
7545 }
7547 /* Build a tree from GNAT_LIST, a possibly-empty list of statements.
7548 If BINDING_P is true, push and pop a binding level around the list. */
7550 static tree
7552 {
7562 }
7563 \f
7564 /* Generate GIMPLE in place for the expression at *EXPR_P. */
7566 int
7569 {
7571 tree op;
7577 {
7579 /* If this is for a scalar, just make a VAR_DECL for it. If for
7580 an aggregate, get a null pointer of the appropriate type and
7581 dereference it. */
7585 integer_zero_node));
7586 else
7587 {
7590 }
7596 /* We should only do this if we are just elaborating for side-effects,
7597 but we can't know that yet. */
7604 /* If we are taking the address of a constant CONSTRUCTOR, make sure it
7605 is put into static memory. We know that it's going to be read-only
7606 given the semantics we have and it must be in static memory when the
7607 reference is in an elaboration procedure. */
7609 {
7613 }
7620 /* If we are view-converting a CONSTRUCTOR or a call from an aggregate
7621 type to a scalar one, explicitly create the local temporary. That's
7622 required if the type is passed by reference. */
7626 {
7635 }
7642 /* The expressions for the RM bounds must be gimplified to ensure that
7643 they are properly elaborated. See gimplify_decl_expr. */
7647 {
7652 {
7657 {
7661 }
7665 {
7669 }
7671 }
7676 }
7678 /* ... fall through ... */
7682 }
7683 }
7685 /* Generate GIMPLE in place for the statement at *STMT_P. */
7687 static enum gimplify_status
7689 {
7693 {
7699 {
7705 /* Build the condition expression from the test, if any. */
7707 {
7708 /* Deal with the optimization hints. */
7712 annot_expr_ivdep_kind));
7716 annot_expr_no_vector_kind));
7720 annot_expr_vector_kind));
7722 gnu_cond
7725 }
7727 /* Set to emit the statements of the loop. */
7730 /* We first emit the start label and then a conditional jump to the
7731 end label if there's a top condition, then the update if it's at
7732 the top, then the body of the loop, then a conditional jump to
7733 the end label if there's a bottom condition, then the update if
7734 it's at the bottom, and finally a jump to the start label and the
7735 definition of the end label. */
7737 gnu_start_label),
7738 stmt_p);
7759 gnu_end_label),
7760 stmt_p);
7762 }
7765 /* Build a statement to jump to the corresponding end label, then
7766 see if it needs to be conditional. */
7775 }
7776 }
7777 \f
7778 /* Force references to each of the entities in packages withed by GNAT_NODE.
7779 Operate recursively but check that we aren't elaborating something more
7780 than once.
7782 This routine is exclusively called in type_annotate mode, to compute DDA
7783 information for types in withed units, for ASIS use. */
7785 static void
7787 {
7790 /* Process each unit only once. As we trace the context of all relevant
7791 units transitively, including generic bodies, we may encounter the
7792 same generic unit repeatedly. */
7796 /* Save entities in all context units. A body may have an implicit_with
7797 on its own spec, if the context includes a child unit, so don't save
7798 the spec twice. */
7805 {
7809 {
7826 }
7828 {
7829 Node_Id gnat_body
7832 /* Retrieve compilation unit node of generic body. */
7837 /* If body is available, elaborate its context. */
7840 }
7841 }
7845 }
7846 \f
7847 /* Do the processing of GNAT_NODE, an N_Freeze_Entity. */
7849 static void
7851 {
7856 /* If this is a package, we need to generate code for the package. */
7858 {
7859 insert_code_for
7863 }
7865 /* Don't do anything for class-wide types as they are always transformed
7866 into their root type. */
7870 /* Check for an old definition. This freeze node might be for an Itype. */
7871 gnu_old
7874 /* If this entity has an address representation clause, GNU_OLD is the
7875 address, so discard it here. */
7879 /* Don't do anything for subprograms that may have been elaborated before
7880 their freeze nodes. This can happen, for example, because of an inner
7881 call in an instance body or because of previous compilation of a spec
7882 for inlining purposes. */
7890 /* If we have a non-dummy type old tree, we have nothing to do, except
7891 aborting if this is the public view of a private type whose full view was
7892 not delayed, as this node was never delayed as it should have been. We
7893 let this happen for concurrent types and their Corresponding_Record_Type,
7894 however, because each might legitimately be elaborated before its own
7895 freeze node, e.g. while processing the other. */
7899 {
7907 }
7909 /* Reset the saved tree, if any, and elaborate the object or type for real.
7910 If there is a full view, elaborate it and use the result. And, if this
7911 is the root type of a class-wide type, reuse it for the latter. */
7913 {
7918 {
7925 {
7928 }
7929 }
7935 }
7939 {
7948 /* Propagate back-annotations from full view to partial view. */
7958 /* The above call may have defined this entity (the simplest example
7959 of this is when we have a private enumeral type since the bounds
7960 will have the public view). */
7963 }
7964 else
7965 {
7966 tree gnu_init
7972 }
7979 /* If we have an old type and we've made pointers to this type, update those
7980 pointers. If this is a Taft amendment type in the main unit, we need to
7981 mark the type as used since other units referencing it don't see the full
7982 declaration and, therefore, cannot mark it as used themselves. */
7984 {
7989 }
7990 }
7991 \f
7992 /* Elaborate decls in the lists GNAT_DECLS and GNAT_DECLS2, if present.
7993 We make two passes, one to elaborate anything other than bodies (but
7994 we declare a function if there was no spec). The second pass
7995 elaborates the bodies.
7997 GNAT_END_LIST gives the element in the list past the end. Normally,
7998 this is Empty, but can be First_Real_Statement for a
7999 Handled_Sequence_Of_Statements.
8001 We make a complete pass through both lists if PASS1P is true, then make
8002 the second pass over both lists if PASS2P is true. The lists usually
8003 correspond to the public and private parts of a package. */
8005 static void
8008 {
8010 Node_Id gnat_decl;
8020 {
8021 /* For package specs, we recurse inside the declarations,
8022 thus taking the two pass approach inside the boundary. */
8030 /* Similarly for any declarations in the actions of a
8031 freeze node. */
8033 {
8036 }
8038 /* Package bodies with freeze nodes get their elaboration deferred
8039 until the freeze node, but the code must be placed in the right
8040 place, so record the code position now. */
8048 (Corresponding_Spec
8051 record_code_position
8054 /* We defer most subprogram bodies to the second pass. */
8056 {
8058 {
8064 }
8065 }
8067 /* For bodies and stubs that act as their own specs, the entity
8068 itself must be elaborated in the first pass, because it may
8069 be used in other declarations. */
8071 {
8072 Node_Id gnat_subprog_id
8079 }
8081 /* Concurrent stubs stand for the corresponding subprogram bodies,
8082 which are deferred like other bodies. */
8085 ;
8087 else
8089 }
8091 /* Here we elaborate everything we deferred above except for package bodies,
8092 which are elaborated at their freeze nodes. Note that we must also
8093 go inside things (package specs and freeze nodes) the first pass did. */
8099 {
8115 }
8116 }
8117 \f
8118 /* Make a unary operation of kind CODE using build_unary_op, but guard
8119 the operation by an overflow check. CODE can be one of NEGATE_EXPR
8120 or ABS_EXPR. GNU_TYPE is the type desired for the result. Usually
8121 the operation is to be performed in that type. GNAT_NODE is the gnat
8122 node conveying the source location for which the error should be
8123 signaled. */
8125 static tree
8127 Node_Id gnat_node)
8128 {
8137 }
8139 /* Make a binary operation of kind CODE using build_binary_op, but guard
8140 the operation by an overflow check. CODE can be one of PLUS_EXPR,
8141 MINUS_EXPR or MULT_EXPR. GNU_TYPE is the type desired for the result.
8142 Usually the operation is to be performed in that type. GNAT_NODE is
8143 the GNAT node conveying the source location for which the error should
8144 be signaled. */
8146 static tree
8149 {
8159 /* Assert that the precision is a power of 2. */
8162 /* Prefer a constant or known-positive rhs to simplify checks. */
8168 {
8172 }
8176 /* If we can fold the expression to a constant, just return it.
8177 The caller will deal with overflow, no need to generate a check. */
8182 ? boolean_false_node
8185 /* ??? Should use more efficient check for operand_equal_p (lhs, rhs, 0) */
8187 /* Try a few strategies that may be cheaper than the general
8188 code at the end of the function, if the rhs is not known.
8189 The strategies are:
8190 - Call library function for 64-bit multiplication (complex)
8191 - Widen, if input arguments are sufficiently small
8192 - Determine overflow using wrapped result for addition/subtraction. */
8195 {
8196 /* Even for add/subtract double size to get another base type. */
8200 {
8206 }
8210 {
8216 check = build_binary_op
8223 return
8225 }
8228 {
8230 tree wrapped_expr
8236 /* Overflow when (rhs < 0) ^ (wrapped_expr < lhs)), for addition
8237 or when (rhs < 0) ^ (wrapped_expr > lhs) for subtraction. */
8238 check
8242 boolean_type_node,
8245 return
8247 }
8248 }
8251 {
8253 /* When rhs >= 0, overflow when lhs > type_max - rhs. */
8258 /* When rhs < 0, overflow when lhs < type_min - rhs. */
8265 /* When rhs >= 0, overflow when lhs < type_min + rhs. */
8270 /* When rhs < 0, overflow when lhs > type_max + rhs. */
8277 /* The check here is designed to be efficient if the rhs is constant,
8278 but it will work for any rhs by using integer division.
8279 Four different check expressions determine whether X * C overflows,
8280 depending on C.
8281 C == 0 => false
8282 C > 0 => X > type_max / C || X < type_min / C
8283 C == -1 => X == type_min
8284 C < -1 => X > type_min / C || X < type_max / C */
8289 check_pos
8292 rhs),
8295 boolean_type_node,
8298 boolean_type_node,
8301 check_neg
8306 type_min),
8309 boolean_type_node,
8312 boolean_type_node,
8318 }
8321 check_pos);
8324 }
8326 /* Emit code for a range check. GNU_EXPR is the expression to be checked,
8327 GNAT_RANGE_TYPE the gnat type or subtype containing the bounds against
8328 which we have to check. GNAT_NODE is the GNAT node conveying the source
8329 location for which the error should be signaled. */
8331 static tree
8333 {
8337 /* If GNU_EXPR has GNAT_RANGE_TYPE as its base type, no check is needed.
8338 This can for example happen when translating 'Val or 'Value. */
8342 /* Range checks can only be applied to types with ranges. */
8346 /* If GNU_EXPR has an integral type that is narrower than GNU_RANGE_TYPE,
8347 we can't do anything since we might be truncating the bounds. No
8348 check is needed in this case. */
8354 /* Checked expressions must be evaluated only once. */
8357 /* Note that the form of the check is
8358 (not (expr >= lo)) or (not (expr <= hi))
8359 the reason for this slightly convoluted form is that NaNs
8360 are not considered to be in range in the float case. */
8361 return emit_check
8363 invert_truthvalue
8367 TYPE_MIN_VALUE
8369 invert_truthvalue
8373 TYPE_MAX_VALUE
8376 }
8377 \f
8378 /* Emit code for an index check. GNU_ARRAY_OBJECT is the array object which
8379 we are about to index, GNU_EXPR is the index expression to be checked,
8380 GNU_LOW and GNU_HIGH are the lower and upper bounds against which GNU_EXPR
8381 has to be checked. Note that for index checking we cannot simply use the
8382 emit_range_check function (although very similar code needs to be generated
8383 in both cases) since for index checking the array type against which we are
8384 checking the indices may be unconstrained and consequently we need to get
8385 the actual index bounds from the array object itself (GNU_ARRAY_OBJECT).
8386 The place where we need to do that is in subprograms having unconstrained
8387 array formal parameters. GNAT_NODE is the GNAT node conveying the source
8388 location for which the error should be signaled. */
8390 static tree
8393 {
8394 tree gnu_expr_check;
8396 /* Checked expressions must be evaluated only once. */
8399 /* Must do this computation in the base type in case the expression's
8400 type is an unsigned subtypes. */
8403 /* If GNU_LOW or GNU_HIGH are a PLACEHOLDER_EXPR, qualify them by
8404 the object we are handling. */
8408 return emit_check
8411 gnu_expr_check,
8413 gnu_low)),
8415 gnu_expr_check,
8417 gnu_high))),
8419 }
8420 \f
8421 /* GNU_COND contains the condition corresponding to an access, discriminant or
8422 range check of value GNU_EXPR. Build a COND_EXPR that returns GNU_EXPR if
8423 GNU_COND is false and raises a CONSTRAINT_ERROR if GNU_COND is true.
8424 REASON is the code that says why the exception was raised. GNAT_NODE is
8425 the GNAT node conveying the source location for which the error should be
8426 signaled. */
8428 static tree
8430 {
8431 tree gnu_call
8433 tree gnu_result
8437 gnu_expr);
8439 /* GNU_RESULT has side effects if and only if GNU_EXPR has:
8440 we don't need to evaluate it just for the check. */
8444 }
8445 \f
8446 /* Return an expression that converts GNU_EXPR to GNAT_TYPE, doing overflow
8447 checks if OVERFLOW_P is true and range checks if RANGE_P is true.
8448 GNAT_TYPE is known to be an integral type. If TRUNCATE_P true, do a
8449 float to integer conversion with truncation; otherwise round.
8450 GNAT_NODE is the GNAT node conveying the source location for which the
8451 error should be signaled. */
8453 static tree
8456 {
8463 /* If we are not doing any checks, the output is an integral type and the
8464 input is not a floating-point type, just do the conversion. This is
8465 required for packed array types and is simpler in all cases anyway. */
8467 && !overflowp
8472 /* First convert the expression to its base type. This
8473 will never generate code, but makes the tests below much simpler.
8474 But don't do this if converting from an integer type to an unconstrained
8475 array type since then we need to get the bounds from the original
8476 (unpacked) type. */
8480 /* If overflow checks are requested, we need to be sure the result will
8481 fit in the output base type. But don't do this if the input
8482 is integer and the output floating-point. */
8485 {
8486 /* Ensure GNU_EXPR only gets evaluated once. */
8494 /* Convert the lower bounds to signed types, so we're sure we're
8495 comparing them properly. Likewise, convert the upper bounds
8496 to unsigned types. */
8510 /* Check each bound separately and only if the result bound
8511 is tighter than the bound on the input type. Note that all the
8512 types are base types, so the bounds must be constant. Also,
8513 the comparison is done in the base type of the input, which
8514 always has the proper signedness. First check for input
8515 integer (which means output integer), output float (which means
8516 both float), or mixed, in which case we always compare.
8517 Note that we have to do the comparison which would *fail* in the
8518 case of an error since if it's an FP comparison and one of the
8519 values is a NaN or Inf, the comparison will fail. */
8526 gnu_cond
8527 = invert_truthvalue
8530 gnu_out_lb)));
8538 gnu_cond
8540 invert_truthvalue
8542 gnu_input,
8544 gnu_out_ub))));
8549 }
8551 /* Now convert to the result base type. If this is a non-truncating
8552 float-to-integer conversion, round. */
8556 {
8562 /* The following calculations depend on proper rounding to even
8563 of each arithmetic operation. In order to prevent excess
8564 precision from spoiling this property, use the widest hardware
8565 floating-point type if FP_ARITH_MAY_WIDEN is true. */
8566 calc_type
8569 /* Compute the exact value calc_type'Pred (0.5) at compile time. */
8573 half_minus_pred_half);
8576 /* If the input is strictly negative, subtract this value
8577 and otherwise add it from the input. For 0.5, the result
8578 is exactly between 1.0 and the machine number preceding 1.0
8579 (for calc_type). Since the last bit of 1.0 is even, this 0.5
8580 will round to 1.0, while all other number with an absolute
8581 value less than 0.5 round to 0.0. For larger numbers exactly
8582 halfway between integers, rounding will always be correct as
8583 the true mathematical result will be closer to the higher
8584 integer compared to the lower one. So, this constant works
8585 for all floating-point numbers.
8587 The reason to use the same constant with subtract/add instead
8588 of a positive and negative constant is to allow the comparison
8589 to be scheduled in parallel with retrieval of the constant and
8590 conversion of the input to the calc_type (if necessary). */
8595 gnu_comp
8597 gnu_add_pred_half
8599 gnu_subtract_pred_half
8603 }
8609 else
8612 /* Finally, do the range check if requested. Note that if the result type
8613 is a modular type, the range check is actually an overflow check. */
8620 }
8621 \f
8622 /* Return true if GNU_EXPR can be directly addressed. This is the case
8623 unless it is an expression involving computation or if it involves a
8624 reference to a bitfield or to an object not sufficiently aligned for
8625 its type. If GNU_TYPE is non-null, return true only if GNU_EXPR can
8626 be directly addressed as an object of this type.
8628 *** Notes on addressability issues in the Ada compiler ***
8630 This predicate is necessary in order to bridge the gap between Gigi
8631 and the middle-end about addressability of GENERIC trees. A tree
8632 is said to be addressable if it can be directly addressed, i.e. if
8633 its address can be taken, is a multiple of the type's alignment on
8634 strict-alignment architectures and returns the first storage unit
8635 assigned to the object represented by the tree.
8637 In the C family of languages, everything is in practice addressable
8638 at the language level, except for bit-fields. This means that these
8639 compilers will take the address of any tree that doesn't represent
8640 a bit-field reference and expect the result to be the first storage
8641 unit assigned to the object. Even in cases where this will result
8642 in unaligned accesses at run time, nothing is supposed to be done
8643 and the program is considered as erroneous instead (see PR c/18287).
8645 The implicit assumptions made in the middle-end are in keeping with
8646 the C viewpoint described above:
8647 - the address of a bit-field reference is supposed to be never
8648 taken; the compiler (generally) will stop on such a construct,
8649 - any other tree is addressable if it is formally addressable,
8650 i.e. if it is formally allowed to be the operand of ADDR_EXPR.
8652 In Ada, the viewpoint is the opposite one: nothing is addressable
8653 at the language level unless explicitly declared so. This means
8654 that the compiler will both make sure that the trees representing
8655 references to addressable ("aliased" in Ada parlance) objects are
8656 addressable and make no real attempts at ensuring that the trees
8657 representing references to non-addressable objects are addressable.
8659 In the first case, Ada is effectively equivalent to C and handing
8660 down the direct result of applying ADDR_EXPR to these trees to the
8661 middle-end works flawlessly. In the second case, Ada cannot afford
8662 to consider the program as erroneous if the address of trees that
8663 are not addressable is requested for technical reasons, unlike C;
8664 as a consequence, the Ada compiler must arrange for either making
8665 sure that this address is not requested in the middle-end or for
8666 compensating by inserting temporaries if it is requested in Gigi.
8668 The first goal can be achieved because the middle-end should not
8669 request the address of non-addressable trees on its own; the only
8670 exception is for the invocation of low-level block operations like
8671 memcpy, for which the addressability requirements are lower since
8672 the type's alignment can be disregarded. In practice, this means
8673 that Gigi must make sure that such operations cannot be applied to
8674 non-BLKmode bit-fields.
8676 The second goal is achieved by means of the addressable_p predicate,
8677 which computes whether a temporary must be inserted by Gigi when the
8678 address of a tree is requested; if so, the address of the temporary
8679 will be used in lieu of that of the original tree and some glue code
8680 generated to connect everything together. */
8682 static bool
8684 {
8685 /* For an integral type, the size of the actual type of the object may not
8686 be greater than that of the expected type, otherwise an indirect access
8687 in the latter type wouldn't correctly set all the bits of the object. */
8693 /* The size of the actual type of the object may not be smaller than that
8694 of the expected type, otherwise an indirect access in the latter type
8695 would be larger than the object. But only record types need to be
8696 considered in practice for this case. */
8703 {
8708 /* All DECLs are addressable: if they are in a register, we can force
8709 them to memory. */
8714 /* Taking the address of a dereference yields the original pointer. */
8719 /* Taking the address yields a pointer to the constant pool. */
8723 /* Taking the address of a static constructor yields a pointer to the
8724 tree constant pool. */
8736 /* All rvalues are deemed addressable since taking their address will
8737 force a temporary to be created by the middle-end. */
8741 /* The address of a compound expression is that of its 2nd operand. */
8745 /* We accept &COND_EXPR as soon as both operands are addressable and
8746 expect the outcome to be the address of the selected operand. */
8752 /* Even with DECL_BIT_FIELD cleared, we have to ensure that
8753 the field is sufficiently aligned, in case it is subject
8754 to a pragma Component_Alignment. But we don't need to
8755 check the alignment of the containing record, as it is
8756 guaranteed to be not smaller than that of its most
8757 aligned field that is not a bit-field. */
8758 && (!STRICT_ALIGNMENT
8761 /* The field of a padding record is always addressable. */
8775 {
8776 /* This is addressable if we can avoid a copy. */
8780 && (!STRICT_ALIGNMENT
8785 && (!STRICT_ALIGNMENT
8791 }
8795 }
8796 }
8797 \f
8798 /* Do the processing for the declaration of a GNAT_ENTITY, a type. If
8799 a separate Freeze node exists, delay the bulk of the processing. Otherwise
8800 make a GCC type for GNAT_ENTITY and set up the correspondence. */
8802 void
8804 {
8805 tree gnu_old
8807 tree gnu_new;
8809 /* If we are to delay elaboration of this type, just do any
8810 elaborations needed for expressions within the declaration and
8811 make a dummy type entry for this node and its Full_View (if
8812 any) in case something points to it. Don't do this if it
8813 has already been done (the only way that can happen is if
8814 the private completion is also delayed). */
8820 {
8824 {
8829 {
8833 }
8834 }
8837 }
8839 /* If we saved away a dummy type for this node it means that this
8840 made the type that corresponds to the full type of an incomplete
8841 type. Clear that type for now and then update the type in the
8842 pointers. */
8844 {
8849 }
8851 /* Now fully elaborate the type. */
8855 /* If we have an old type and we've made pointers to this type, update those
8856 pointers. If this is a Taft amendment type in the main unit, we need to
8857 mark the type as used since other units referencing it don't see the full
8858 declaration and, therefore, cannot mark it as used themselves. */
8860 {
8865 }
8867 /* If this is a record type corresponding to a task or protected type
8868 that is a completion of an incomplete type, perform a similar update
8869 on the type. ??? Including protected types here is a guess. */
8873 {
8874 tree gnu_task_old
8884 }
8885 }
8886 \f
8887 /* GNAT_ENTITY is the type of the resulting constructor, GNAT_ASSOC is the
8888 front of the Component_Associations of an N_Aggregate and GNU_TYPE is the
8889 GCC type of the corresponding record type. Return the CONSTRUCTOR. */
8891 static tree
8893 {
8896 /* We test for GNU_FIELD being empty in the case where a variant
8897 was the last thing since we don't take things off GNAT_ASSOC in
8898 that case. We check GNAT_ASSOC in case we have a variant, but it
8899 has no fields. */
8902 {
8907 /* The expander is supposed to put a single component selector name
8908 in every record component association. */
8911 /* Ignore fields that have Corresponding_Discriminants since we'll
8912 be setting that field in the parent. */
8917 /* Also ignore discriminants of Unchecked_Unions. */
8922 /* Before assigning a value in an aggregate make sure range checks
8923 are done if required. Then convert to the type of the field. */
8929 /* Add the field and expression to the list. */
8931 }
8935 #ifdef ENABLE_CHECKING
8936 /* Verify that every entry in GNU_LIST was used. */
8939 #endif
8942 }
8944 /* Build a possibly nested constructor for array aggregates. GNAT_EXPR is
8945 the first element of an array aggregate. It may itself be an aggregate.
8946 GNU_ARRAY_TYPE is the GCC type corresponding to the array aggregate.
8947 GNAT_COMPONENT_TYPE is the type of the array component; it is needed
8948 for range checking. */
8950 static tree
8952 Entity_Id gnat_component_type)
8953 {
8955 tree gnu_expr;
8959 {
8960 /* If the expression is itself an array aggregate then first build the
8961 innermost constructor if it is part of our array (multi-dimensional
8962 case). */
8968 gnat_component_type);
8969 else
8970 {
8973 /* Before assigning the element to the array, make sure it is
8974 in range. */
8977 }
8984 integer_one_node));
8985 }
8988 }
8989 \f
8990 /* Subroutine of assoc_to_constructor: VALUES is a list of field associations,
8991 some of which are from RECORD_TYPE. Return a CONSTRUCTOR consisting
8992 of the associations that are from RECORD_TYPE. If we see an internal
8993 record, make a recursive call to fill it in as well. */
8995 static tree
8997 {
9002 {
9005 /* _Parent is an internal field, but may have values in the aggregate,
9006 so check for values first. */
9008 {
9011 }
9014 {
9019 }
9020 else
9021 /* If we have a record subtype, the names will match, but not the
9022 actual FIELD_DECLs. */
9025 {
9028 }
9034 }
9037 }
9038 \f
9039 /* Process a N_Validate_Unchecked_Conversion node. */
9041 static void
9043 {
9047 /* If the target is a pointer type, see if we are either converting from a
9048 non-pointer or from a pointer to a type with a different alias set and
9049 warn if so, unless the pointer has been marked to alias everything. */
9052 {
9062 target_alias_set)))
9063 {
9067 gnat_node);
9070 }
9071 }
9073 /* Likewise if the target is a fat pointer type, but we have no mechanism to
9074 mitigate the problem in this case, so we unconditionally warn. */
9076 {
9077 tree gnu_source_desig_type
9081 tree gnu_target_desig_type
9088 target_alias_set)))
9089 {
9093 gnat_node);
9094 }
9095 }
9096 }
9097 \f
9098 /* EXP is to be treated as an array or record. Handle the cases when it is
9099 an access object and perform the required dereferences. */
9101 static tree
9103 {
9104 /* If the type is a pointer, dereference it. */
9109 /* If we got a padded type, remove it too. */
9114 }
9115 \f
9116 /* Convert SLOC into LOCUS. Return true if SLOC corresponds to a source code
9117 location and false if it doesn't. In the former case, set the Gigi global
9118 variable REF_FILENAME to the simple debug file name as given by sinput.
9119 If clear_column is true, set column information to 0. */
9121 static bool
9123 {
9128 {
9131 }
9132 else
9133 {
9139 /* We can have zero if pragma Source_Reference is in effect. */
9143 /* Translate the location. */
9145 }
9147 ref_filename
9148 = IDENTIFIER_POINTER
9149 (get_identifier
9153 }
9155 /* Similar to the above, not clearing the column information. */
9157 bool
9159 {
9161 }
9163 /* Similar to set_expr_location, but start with the Sloc of GNAT_NODE and
9164 don't do anything if it doesn't correspond to a source location. */
9166 static void
9168 {
9169 location_t locus;
9175 }
9177 /* Similar to the above, not clearing the column information. */
9179 static void
9181 {
9183 }
9185 /* More elaborate version of set_expr_location_from_node to be used in more
9186 general contexts, for example the result of the translation of a generic
9187 GNAT node. */
9189 static void
9191 {
9192 /* Set the location information on the node if it is a real expression.
9193 References can be reused for multiple GNAT nodes and they would get
9194 the location information of their last use. Also make sure not to
9195 overwrite an existing location as it is probably more precise. */
9198 {
9199 CASE_CONVERT:
9208 /* ... fall through ... */
9212 {
9215 }
9217 }
9218 }
9219 \f
9220 /* Return a colon-separated list of encodings contained in encoded Ada
9221 name. */
9225 {
9229 }
9231 /* Extract the Ada name from an encoded name. */
9235 {
9239 }
9240 \f
9241 /* Post an error message. MSG is the error message, properly annotated.
9242 NODE is the node at which to post the error and the node to use for the
9243 '&' substitution. */
9245 void
9247 {
9248 String_Template temp;
9249 String_Pointer sp;
9259 }
9261 /* Similar to post_error, but NODE is the node at which to post the error and
9262 ENT is the node to use for the '&' substitution. */
9264 void
9266 {
9267 String_Template temp;
9268 String_Pointer sp;
9278 }
9280 /* Similar to post_error_ne, but NUM is the number to use for the '^'. */
9282 void
9284 {
9287 }
9289 /* Set the end_locus information for GNU_NODE, if any, from an explicit end
9290 location associated with GNAT_NODE or GNAT_NODE itself, whichever makes
9291 most sense. Return true if a sensible assignment was performed. */
9293 static bool
9295 {
9297 location_t end_locus;
9299 /* Pick the GNAT node of which we'll take the sloc to assign to the GCC node
9300 end_locus when there is one. We consider only GNAT nodes with a possible
9301 End_Label attached. If the End_Label actually was unassigned, fallback
9302 on the original node. We'd better assign an explicit sloc associated with
9303 the outer construct in any case. */
9306 {
9319 }
9323 /* Some expanded subprograms have neither an End_Label nor a Sloc
9324 attached. Notify that to callers. For a block statement with no
9325 End_Label, clear column information, so that the tree for a
9326 transient block does not receive the sloc of a source condition. */
9334 {
9345 }
9346 }
9347 \f
9348 /* Similar to post_error_ne, but T is a GCC tree representing the number to
9349 write. If T represents a constant, the text inside curly brackets in
9350 MSG will be output (presumably including a '^'). Otherwise it will not
9351 be output and the text inside square brackets will be output instead. */
9353 void
9355 {
9362 {
9365 }
9366 else
9370 {
9376 ;
9377 else
9379 }
9384 }
9386 /* Similar to post_error_ne_tree, but NUM is a second integer to write. */
9388 void
9391 {
9394 }
9395 \f
9396 /* Initialize the table that maps GNAT codes to GCC codes for simple
9397 binary and unary operations. */
9399 static void
9401 {
9427 }
9429 /* Return a label to branch to for the exception type in KIND or NULL_TREE
9430 if none. */
9432 tree
9434 {
9441 else
9443 }
9445 /* Return the decl for the current elaboration procedure. */
9447 tree
9449 {
9451 }