| blob | f91f4b83a6e4545598f84f460ec6493e2a2f6887 |
1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * T R A N S *
6 * *
7 * C Implementation File *
8 * *
9 * Copyright (C) 1992-2013, 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 ****************************************************************************/
62 /* We should avoid allocating more than ALLOCA_THRESHOLD bytes via alloca,
63 for fear of running out of stack space. If we need more, we use xmalloc
64 instead. */
65 #define ALLOCA_THRESHOLD 1000
67 /* Let code below know whether we are targeting VMS without need of
68 intrusive preprocessor directives. */
69 #ifndef TARGET_ABI_OPEN_VMS
70 #define TARGET_ABI_OPEN_VMS 0
71 #endif
73 /* In configurations where blocks have no end_locus attached, just
74 sink assignments into a dummy global. */
75 #ifndef BLOCK_SOURCE_END_LOCATION
77 #define BLOCK_SOURCE_END_LOCATION(BLOCK) block_end_locus_sink
78 #endif
80 /* For efficient float-to-int rounding, it is necessary to know whether
81 floating-point arithmetic may use wider intermediate results. When
82 FP_ARITH_MAY_WIDEN is not defined, be conservative and only assume
83 that arithmetic does not widen if double precision is emulated. */
84 #ifndef FP_ARITH_MAY_WIDEN
85 #if defined(HAVE_extendsfdf2)
86 #define FP_ARITH_MAY_WIDEN HAVE_extendsfdf2
87 #else
88 #define FP_ARITH_MAY_WIDEN 0
89 #endif
90 #endif
92 /* Pointers to front-end tables accessed through macros. */
102 /* Highest number in the front-end node table. */
105 /* Current node being treated, in case abort called. */
106 Node_Id error_gnat_node;
108 /* True when gigi is being called on an analyzed but unexpanded
109 tree, and the only purpose of the call is to properly annotate
110 types with representation information. */
113 /* Current filename without path. */
117 /* List of N_Validate_Unchecked_Conversion nodes in the unit. */
120 /* When not optimizing, we cache the 'First, 'Last and 'Length attributes
121 of unconstrained array IN parameters to avoid emitting a great deal of
122 redundant instructions to recompute them each time. */
126 tree first;
127 tree last;
128 tree length;
129 };
136 bitmap named_ret_val;
139 };
141 #define f_parm_attr_cache \
142 DECL_STRUCT_FUNCTION (current_function_decl)->language->parm_attr_cache
144 #define f_named_ret_val \
145 DECL_STRUCT_FUNCTION (current_function_decl)->language->named_ret_val
147 #define f_other_ret_val \
148 DECL_STRUCT_FUNCTION (current_function_decl)->language->other_ret_val
150 #define f_gnat_ret \
151 DECL_STRUCT_FUNCTION (current_function_decl)->language->gnat_ret
153 /* A structure used to gather together information about a statement group.
154 We use this to gather related statements, for example the "then" part
155 of a IF. In the case where it represents a lexical scope, we may also
156 have a BLOCK node corresponding to it and/or cleanups. */
163 };
167 /* List of unused struct stmt_group nodes. */
170 /* A structure used to record information on elaboration procedures
171 we've made and need to process.
173 ??? gnat_node should be Node_Id, but gengtype gets confused. */
179 };
183 /* Stack of exception pointer variables. Each entry is the VAR_DECL
184 that stores the address of the raised exception. Nonzero means we
185 are in an exception handler. Not used in the zero-cost case. */
188 /* In ZCX case, current exception pointer. Used to re-raise it. */
191 /* Stack for storing the current elaboration procedure decl. */
194 /* Stack of labels to be used as a goto target instead of a return in
195 some functions. See processing for N_Subprogram_Body. */
198 /* Stack of variable for the return value of a function with copy-in/copy-out
199 parameters. See processing for N_Subprogram_Body. */
202 /* Structure used to record information for a range check. */
204 tree low_bound;
205 tree high_bound;
206 tree type;
207 tree invariant_cond;
208 };
213 /* Structure used to record information for a loop. */
215 tree stmt;
216 tree loop_var;
218 };
223 /* Stack of loop_info structures associated with LOOP_STMT nodes. */
226 /* The stacks for N_{Push,Pop}_*_Label. */
231 /* 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
284 {
285 Node_Id gnat_iter;
286 Entity_Id gnat_literal;
291 #ifdef ORDINARY_MAP_INSTANCE
293 #endif
308 /* ??? Disable the generation of the SCO instance table until after the
309 back-end supports instance based debug info discriminators. */
313 {
314 /* Use the identifier table to make a permanent copy of the filename as
315 the name table gets reallocated after Gigi returns but before all the
316 debugging information is output. The __gnat_to_canonical_file_spec
317 call translates filenames from pragmas Source_Reference that contain
318 host style syntax not understood by gdb. */
320 = IDENTIFIER_POINTER
321 (get_identifier
322 (__gnat_to_canonical_file_spec
325 /* We rely on the order isomorphism between files and line maps. */
328 /* We create the line map for a source file at once, with a fixed number
329 of columns chosen to avoid jumping over the next power of 2. */
331 #ifdef ORDINARY_MAP_INSTANCE
335 #endif
339 }
343 /* Declare the name of the compilation unit as the first global
344 name in order to make the middle-end fully deterministic. */
348 /* 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 /* malloc32 is a function declaration tree for a function to allocate
421 32-bit memory on a 64-bit system. Needed only on 64-bit VMS. */
422 malloc32_decl
428 /* free is a function declaration tree for a function to free memory. */
429 free_decl
432 ptr_void_type_node,
433 NULL_TREE),
435 Empty);
437 /* This is used for 64-bit multiplication with overflow checking. */
438 mulv64_decl
443 Empty);
445 /* Name of the _Parent field in tagged record types. */
448 /* Name of the Exception_Data type defined in System.Standard_Library. */
449 exception_data_name_id
452 /* Make the types and functions used for exception processing. */
453 jmpbuf_type
459 /* Functions to get and set the jumpbuf pointer for the current thread. */
460 get_jmpbuf_decl
461 = create_subprog_decl
467 set_jmpbuf_decl
468 = create_subprog_decl
471 NULL_TREE),
475 /* setjmp returns an integer and has one operand, which is a pointer to
476 a jmpbuf. */
477 setjmp_decl
478 = create_subprog_decl
481 NULL_TREE),
486 /* update_setjmp_buf updates a setjmp buffer from the current stack pointer
487 address. */
488 update_setjmp_buf_decl
489 = create_subprog_decl
496 /* Hooks to call when entering/leaving an exception handler. */
497 ftype
500 begin_handler_decl
506 end_handler_decl
512 unhandled_except_decl
514 NULL_TREE,
519 reraise_zcx_decl
523 /* Indicate that these never return. */
530 /* If in no exception handlers mode, all raise statements are redirected to
531 __gnat_last_chance_handler. No need to redefine raise_nodefer_decl since
532 this procedure will never be called in this mode. */
534 {
535 tree decl
536 = create_subprog_decl
539 build_pointer_type
549 }
550 else
551 {
552 /* Otherwise, make one decl for each exception reason. */
558 i == CE_Index_Check_Failed
562 }
564 /* Set the types that GCC and Gigi use from the front end. */
565 exception_type
569 /* Make other functions used for exception processing. */
570 get_excptr_decl
571 = create_subprog_decl
574 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 long_long_float_type
627 {
628 /* In this case, the builtin floating point types are VAX float,
629 so make up a type for use. */
635 }
636 else
639 /* Dummy objects to materialize "others" and "all others" in the exception
640 tables. These are exported by a-exexpr-gcc.adb, so see this unit for
641 the types to use. */
642 others_decl
648 all_others_decl
654 unhandled_others_decl
662 /* Install the builtins we might need, either internally or as
663 user available facilities for Intrinsic imports. */
671 /* Process any Pragma Ident for the main unit. */
676 /* If we are using the GCC exception mechanism, let GCC know. */
680 /* Initialize the GCC support for FP operations. */
683 /* Now translate the compilation unit proper. */
686 /* Then process the N_Validate_Unchecked_Conversion nodes. We do this at
687 the very end to avoid having to second-guess the front-end when we run
688 into dummy nodes during the regular processing. */
693 /* Finally see if we have any elaboration procedures to deal with. */
695 {
698 /* We should have a BIND_EXPR but it may not have any statements in it.
699 If it doesn't have any, we have nothing to do except for setting the
700 flag on the GNAT node. Otherwise, process the function as others. */
706 else
707 {
711 }
712 }
714 /* Destroy ourselves. */
717 /* We cannot track the location of errors past this point. */
719 }
720 \f
721 /* Return a subprogram decl corresponding to __gnat_rcheck_xx for the given
722 CHECK if KIND is EXCEPTION_SIMPLE, or else to __gnat_rcheck_xx_ext. */
724 static tree
726 {
735 {
737 ftype
739 build_pointer_type
742 }
743 else
744 {
749 ftype
751 build_pointer_type
755 }
757 result
762 /* Indicate that it never returns. */
769 }
770 \f
771 /* Return a positive value if an lvalue is required for GNAT_NODE, which is
772 an N_Attribute_Reference. */
774 static int
776 {
778 {
815 }
816 }
818 /* Return a positive value if an lvalue is required for GNAT_NODE. GNU_TYPE
819 is the type that will be used for GNAT_NODE in the translated GNU tree.
820 CONSTANT indicates whether the underlying object represented by GNAT_NODE
821 is constant in the Ada sense. If it is, ADDRESS_OF_CONSTANT indicates
822 whether its value is the address of a constant and ALIASED whether it is
823 aliased. If it isn't, ADDRESS_OF_CONSTANT and ALIASED are ignored.
825 The function climbs up the GNAT tree starting from the node and returns 1
826 upon encountering a node that effectively requires an lvalue downstream.
827 It returns int instead of bool to facilitate usage in non-purely binary
828 logic contexts. */
830 static int
833 {
837 {
847 /* If the parameter is by reference, an lvalue is required. */
853 /* Only the array expression can require an lvalue. */
857 /* ??? Consider that referencing an indexed component with a
858 non-constant index forces the whole aggregate to memory.
859 Note that N_Integer_Literal is conservative, any static
860 expression in the RM sense could probably be accepted. */
867 /* ... fall through ... */
870 /* Only the array expression can require an lvalue. */
884 /* We need to make a real renaming only if the constant object is
885 aliased or if we may use a renaming pointer; otherwise we can
886 optimize and return the rvalue. We make an exception if the object
887 is an identifier since in this case the rvalue can be propagated
888 attached to the CONST_DECL. */
890 || aliased
891 /* This should match the constant case of the renaming code. */
892 || Is_Composite_Type
897 /* We cannot use a constructor if this is an atomic object because
898 the actual assignment might end up being done component-wise. */
902 /* We don't use a constructor if this is a class-wide object
903 because the effective type of the object is the equivalent
904 type of the class-wide subtype and it smashes most of the
905 data into an array of bytes to which we cannot convert. */
910 /* We cannot use a constructor if the LHS is an atomic object because
911 the actual assignment might end up being done component-wise. */
921 /* ... fall through ... */
925 /* We must look through all conversions because we may need to bypass
926 an intermediate conversion that is meant to be purely formal. */
932 /* We should only reach here through the N_Qualified_Expression case.
933 Force an lvalue for composite types since a block-copy to the newly
934 allocated area of memory is made. */
938 /* We look through dereferences for address of constant because we need
939 to handle the special cases listed above. */
945 /* ... fall through ... */
949 }
952 }
954 /* Subroutine of gnat_to_gnu to translate gnat_node, an N_Identifier,
955 to a GCC tree, which is returned. GNU_RESULT_TYPE_P is a pointer
956 to where we should place the result type. */
958 static tree
960 {
964 /* Whether we should require an lvalue for GNAT_NODE. Needed in
965 specific circumstances only, so evaluated lazily. < 0 means
966 unknown, > 0 means known true, 0 means known false. */
969 /* If GNAT_NODE is a constant, whether we should use the initialization
970 value instead of the constant entity, typically for scalars with an
971 address clause when the parent doesn't require an lvalue. */
974 /* If the Etype of this node does not equal the Etype of the Entity,
975 something is wrong with the entity map, probably in generic
976 instantiation. However, this does not apply to types. Since we sometime
977 have strange Ekind's, just do this test for objects. Also, if the Etype of
978 the Entity is private, the Etype of the N_Identifier is allowed to be the
979 full type and also we consider a packed array type to be the same as the
980 original type. Similarly, a class-wide type is equivalent to a subtype of
981 itself. Finally, if the types are Itypes, one may be a copy of the other,
982 which is also legal. */
1005 /* If this is a reference to a deferred constant whose partial view is an
1006 unconstrained private type, the proper type is on the full view of the
1007 constant, not on the full view of the type, which may be unconstrained.
1009 This may be a reference to a type, for example in the prefix of the
1010 attribute Position, generated for dispatching code (see Make_DT in
1011 exp_disp,adb). In that case we need the type itself, not is parent,
1012 in particular if it is a derived type */
1019 {
1022 }
1023 else
1024 {
1025 /* We want to use the Actual_Subtype if it has already been elaborated,
1026 otherwise the Etype. Avoid using Actual_Subtype for packed arrays to
1027 simplify things. */
1035 else
1037 }
1039 /* Expand the type of this identifier first, in case it is an enumeral
1040 literal, which only get made when the type is expanded. There is no
1041 order-of-elaboration issue here. */
1044 /* If this is a non-imported elementary constant with an address clause,
1045 retrieve the value instead of a pointer to be dereferenced unless
1046 an lvalue is required. This is generally more efficient and actually
1047 required if this is a static expression because it might be used
1048 in a context where a dereference is inappropriate, such as a case
1049 statement alternative or a record discriminant. There is no possible
1050 volatile-ness short-circuit here since Volatile constants must be
1051 imported per C.6. */
1056 {
1060 }
1063 {
1064 /* If this is a deferred constant, the initializer is attached to
1065 the full view. */
1070 }
1071 else
1074 /* Some objects (such as parameters passed by reference, globals of
1075 variable size, and renamed objects) actually represent the address
1076 of the object. In that case, we must do the dereference. Likewise,
1077 deal with parameters to foreign convention subprograms. */
1082 {
1085 /* If it's a PARM_DECL to foreign convention subprogram, convert it. */
1088 gnu_result
1091 /* If it's a CONST_DECL, return the underlying constant like below. */
1098 /* If it's a renaming pointer and we are at the right binding level,
1099 we can reference the renamed object directly, since the renamed
1100 expression has been protected against multiple evaluations. */
1107 /* Otherwise, do the final dereference. */
1108 else
1109 {
1119 }
1120 }
1122 /* If we have a constant declaration and its initializer, try to return the
1123 latter to avoid the need to call fold in lots of places and the need for
1124 elaboration code if this identifier is used as an initializer itself.
1125 Don't do it for aggregate types that contain a placeholder since their
1126 initializers cannot be manipulated easily. */
1133 {
1139 /* If there is a (corresponding) variable or this is the address of a
1140 constant, we only want to return the initializer if an lvalue isn't
1141 required. Evaluate this now if we have not already done so. */
1143 require_lvalue
1147 /* Finally retrieve the initializer if this is deemed valid. */
1150 }
1152 /* The GNAT tree has the type of a function set to its result type, so we
1153 adjust here. Also use the type of the result if the Etype is a subtype
1154 that is nominally unconstrained. Likewise if this is a deferred constant
1155 of a discriminated type whose full view can be elaborated statically, to
1156 avoid problematic conversions to the nominal subtype. But remove any
1157 padding from the resulting type. */
1164 {
1168 }
1173 }
1174 \f
1175 /* Subroutine of gnat_to_gnu to process gnat_node, an N_Pragma. Return
1176 any statements we generate. */
1178 static tree
1180 {
1182 Node_Id gnat_temp;
1184 /* Do nothing if we are just annotating types and check for (and ignore)
1185 unrecognized pragmas. */
1191 {
1193 /* Do nothing at top level: all such variables are already viewable. */
1200 {
1206 #ifdef ASM_COMMENT_START
1208 #endif
1213 /* Use the value only if it fits into a normal register,
1214 otherwise use the address. */
1223 #ifdef ASM_COMMENT_START
1229 NULL);
1232 #endif
1234 asm_constraint,
1235 NULL_TREE,
1236 tree_cons
1244 }
1251 {
1255 {
1274 }
1275 }
1281 {
1299 }
1308 {
1309 Node_Id gnat_expr;
1310 /* Preserve the location of the pragma. */
1314 diagnostic_t kind;
1319 /* This is the String form: pragma Warnings (String). */
1321 {
1325 }
1327 /* This is the On/Off form: pragma Warnings (On | Off [,String]). */
1329 {
1331 {
1342 }
1345 {
1346 /* pragma Warnings (On | Off, Name) is handled differently. */
1351 }
1352 else
1356 }
1358 else
1361 /* This is the same implementation as in the C family of compilers. */
1363 {
1371 option_index++)
1375 {
1378 }
1379 }
1380 else
1387 }
1392 }
1395 }
1396 \f
1397 /* Subroutine of gnat_to_gnu to translate GNAT_NODE, an N_Attribute node,
1398 to a GCC tree, which is returned. GNU_RESULT_TYPE_P is a pointer to
1399 where we should place the result type. ATTRIBUTE is the attribute ID. */
1401 static tree
1403 {
1408 /* ??? If this is an access attribute for a public subprogram to be used in
1409 a dispatch table, do not translate its type as it's useless there and the
1410 parameter types might be incomplete types coming from a limited with. */
1418 else
1422 /* If the input is a NULL_EXPR, make a new one. */
1424 {
1428 }
1431 {
1434 /* These are just conversions since representation clauses for
1435 enumeration types are handled in the front-end. */
1436 {
1442 }
1447 /* These just add or subtract the constant 1 since representation
1448 clauses for enumeration types are handled in the front-end. */
1453 {
1455 gnu_expr
1456 = emit_check
1458 gnu_expr,
1459 attribute == Attr_Pred
1463 }
1465 gnu_result
1473 /* Conversions don't change addresses but can cause us to miss the
1474 COMPONENT_REF case below, so strip them off. */
1478 /* If we are taking 'Address of an unconstrained object, this is the
1479 pointer to the underlying array. */
1483 /* If we are building a static dispatch table, we have to honor
1484 TARGET_VTABLE_USES_DESCRIPTORS if we want to be compatible
1485 with the C++ ABI. We do it in the non-static case as well,
1486 see gnat_to_gnu_entity, case E_Access_Subprogram_Type. */
1489 {
1491 /* Descriptors can only be built here for top-level functions. */
1499 /* If we're not going to build the descriptor, we have to retrieve
1500 the one which will be built by the linker (or by the compiler
1501 later if a static chain is requested). */
1503 {
1506 gnu_result);
1508 }
1515 {
1517 {
1521 }
1522 else
1528 elt--;
1529 }
1533 }
1535 /* ... fall through ... */
1541 gnu_result
1548 /* For 'Code_Address, find an inner ADDR_EXPR and mark it so that we
1549 don't try to build a trampoline. */
1551 {
1556 }
1558 /* For 'Access, issue an error message if the prefix is a C++ method
1559 since it can use a special calling convention on some platforms,
1560 which cannot be propagated to the access type. */
1565 gnat_node);
1567 /* For other address attributes applied to a nested function,
1568 find an inner ADDR_EXPR and annotate it so that we can issue
1569 a useful warning with -Wtrampolines. */
1571 {
1576 {
1579 /* Check that we're not violating the No_Implicit_Dynamic_Code
1580 restriction. Be conservative if we don't know anything
1581 about the trampoline strategy for the target. */
1583 }
1584 }
1588 {
1590 tree gnu_obj_type;
1594 /* If this is fat pointer, the object must have been allocated with the
1595 template in front of the array. So compute the template address; do
1596 it by converting to a thin pointer. */
1598 gnu_ptr
1600 (TYPE_OBJECT_RECORD_TYPE
1602 gnu_ptr);
1606 /* If this is a thin pointer, the object must have been allocated with
1607 the template in front of the array. So compute the template address
1608 and return it. */
1610 gnu_ptr
1612 gnu_ptr,
1614 byte_position
1615 (DECL_CHAIN
1619 }
1628 /* Remove NOPs and conversions between original and packable version
1629 from GNU_EXPR, and conversions from GNU_PREFIX. We use GNU_EXPR
1630 to see if a COMPONENT_REF was involved. */
1635 == RECORD_TYPE
1644 /* Replace an unconstrained array type with the type of the underlying
1645 array. We can't do this with a call to maybe_unconstrained_array
1646 since we may have a TYPE_DECL. For 'Max_Size_In_Storage_Elements,
1647 use the record type that will be used to allocate the object and its
1648 template. */
1650 {
1654 }
1656 /* If we're looking for the size of a field, return the field size. */
1660 /* Otherwise, if the prefix is an object, or if we are looking for
1661 'Object_Size or 'Max_Size_In_Storage_Elements, the result is the
1662 GCC size of the type. We make an exception for padded objects,
1663 as we do not take into account alignment promotions for the size.
1664 This is in keeping with the object case of gnat_to_gnu_entity. */
1670 {
1671 /* If this is a dereference and we have a special dynamic constrained
1672 subtype on the prefix, use it to compute the size; otherwise, use
1673 the designated subtype. */
1675 {
1677 Node_Id gnat_actual_subtype
1679 tree gnu_ptr_type
1684 {
1685 tree gnu_actual_obj_type
1687 gnu_type
1689 gnu_actual_obj_type,
1692 }
1693 }
1696 }
1698 /* Otherwise, the result is the RM size of the type. */
1699 else
1702 /* Deal with a self-referential size by returning the maximum size for
1703 a type and by qualifying the size with the object otherwise. */
1705 {
1708 else
1710 }
1712 /* If the type contains a template, subtract its size. */
1718 /* For 'Max_Size_In_Storage_Elements, adjust the unit. */
1726 {
1739 else
1740 {
1746 /* If the default alignment of "double" or larger scalar types is
1747 specifically capped and there is an alignment clause neither
1748 on the type nor on the prefix itself, return the cap. */
1750 is_capped_double
1753 is_capped_double
1755 else
1765 else
1767 }
1770 }
1779 {
1786 else
1787 gnu_result
1788 = build_binary_op
1790 build_binary_op
1802 }
1804 /* ... fall through ... */
1807 {
1814 /* Make sure any implicit dereference gets done. */
1818 /* We treat unconstrained array In parameters specially. */
1820 {
1823 /* This is the direct case. */
1828 /* This is the indirect case. Note that we need to be sure that
1829 the access value cannot be null as we'll hoist the load. */
1835 }
1837 /* If the prefix is the view conversion of a constrained array to an
1838 unconstrained form, we retrieve the constrained array because we
1839 might not be able to substitute the PLACEHOLDER_EXPR coming from
1840 the conversion. This can occur with the 'Old attribute applied
1841 to a parameter with an unconstrained type, which gets rewritten
1842 into a constrained local variable very late in the game. */
1845 && !CONTAINS_PLACEHOLDER_P
1848 else
1855 {
1857 tree gnu_type_temp;
1863 ;
1866 }
1873 /* When not optimizing, look up the slot associated with the parameter
1874 and the dimension in the cache and create a new one on failure. */
1876 {
1882 {
1887 }
1888 }
1890 /* Return the cached expression or build a new one. */
1892 {
1894 {
1897 }
1899 gnu_result
1901 }
1904 {
1906 {
1909 }
1911 gnu_result
1913 }
1916 {
1918 {
1921 }
1922 else
1923 {
1924 /* We used to compute the length as max (hb - lb + 1, 0),
1925 which could overflow for some cases of empty arrays, e.g.
1926 when lb == index_type'first. We now compute the length as
1927 (hb >= lb) ? hb - lb + 1 : 0, which would only overflow in
1928 much rarer cases, for extremely large arrays we expect
1929 never to encounter in practice. In addition, the former
1930 computation required the use of potentially constraining
1931 signed arithmetic while the latter doesn't. Note that
1932 the comparison must be done in the original index type,
1933 to avoid any overflow during the conversion. */
1938 gnu_result
1941 comp_type,
1945 gnu_result
1948 boolean_type_node,
1950 gnu_result,
1952 }
1953 }
1955 /* If this has a PLACEHOLDER_EXPR, qualify it by the object we are
1956 handling. Note that these attributes could not have been used on
1957 an unconstrained array type. */
1960 /* Cache the expression we have just computed. Since we want to do it
1961 at run time, we force the use of a SAVE_EXPR and let the gimplifier
1962 create the temporary in the outermost binding level. We will make
1963 sure in Subprogram_Body_to_gnu that it is evaluated on all possible
1964 paths by forcing its evaluation on entry of the function. */
1966 {
1967 gnu_result
1973 else
1975 }
1977 /* Set the source location onto the predicate of the condition in the
1978 'Length case but do not do it if the expression is cached to avoid
1979 messing up the debug info. */
1984 gnat_node);
1987 }
1994 {
1995 HOST_WIDE_INT bitsize;
1996 HOST_WIDE_INT bitpos;
1997 tree gnu_offset;
1998 tree gnu_field_bitpos;
1999 tree gnu_field_offset;
2000 tree gnu_inner;
2008 /* We can have 'Bit on any object, but if it isn't a COMPONENT_REF,
2009 the result is 0. Don't allow 'Bit on a bare component, though. */
2013 {
2016 }
2018 else
2027 {
2035 {
2036 gnu_field_bitpos
2039 gnu_field_offset
2042 }
2043 }
2045 {
2048 }
2049 else
2050 {
2053 }
2056 {
2070 /* ??? Avoid a large unsigned result that will overflow when
2071 converted to the signed universal_integer. */
2074 else
2075 gnu_result
2082 }
2084 /* If this has a PLACEHOLDER_EXPR, qualify it by the object we are
2085 handling. */
2088 }
2092 {
2100 }
2126 /* Note this size cannot be self-referential. */
2136 /* What we want is the offset of the ARRAY field in the record
2137 that the thin pointer designates. */
2145 /* This is just a zero cast to the pointer type for our prefix and
2146 dereferenced. */
2148 gnu_result
2151 integer_zero_node));
2156 {
2163 {
2168 ;
2169 }
2177 && (DECL_BY_COMPONENT_PTR_P
2181 }
2185 /* This abort means that we have an unimplemented attribute. */
2187 }
2189 /* If this is an attribute where the prefix was unused, force a use of it if
2190 it has a side-effect. But don't do it if the prefix is just an entity
2191 name. However, if an access check is needed, we must do it. See second
2192 example in AARM 11.6(5.e). */
2196 gnu_result);
2200 }
2201 \f
2202 /* Subroutine of gnat_to_gnu to translate gnat_node, an N_Case_Statement,
2203 to a GCC tree, which is returned. */
2205 static tree
2207 {
2209 Node_Id gnat_when;
2210 location_t end_locus;
2216 /* The range of values in a case statement is determined by the rules in
2217 RM 5.4(7-9). In almost all cases, this range is represented by the Etype
2218 of the expression. One exception arises in the case of a simple name that
2219 is parenthesized. This still has the Etype of the name, but since it is
2220 not a name, para 7 does not apply, and we need to go to the base type.
2221 This is the only case where parenthesization affects the dynamic
2222 semantics (i.e. the range of possible values at run time that is covered
2223 by the others alternative).
2225 Another exception is if the subtype of the expression is non-static. In
2226 that case, we also have to use the base type. */
2232 /* We build a SWITCH_EXPR that contains the code with interspersed
2233 CASE_LABEL_EXPRs for each label. */
2243 {
2245 Node_Id gnat_choice;
2247 /* First compile all the different case choices for the current WHEN
2248 alternative. */
2251 {
2255 {
2270 /* This represents either a subtype range or a static value of
2271 some kind; Ekind says which. */
2273 {
2279 }
2281 /* ... fall through ... */
2293 }
2295 /* If the case value is a subtype that raises Constraint_Error at
2296 run time because of a wrong bound, then gnu_low or gnu_high is
2297 not translated into an INTEGER_CST. In such a case, we need
2298 to ensure that the when statement is not added in the tree,
2299 otherwise it will crash the gimplifier. */
2302 {
2306 gnat_choice);
2308 }
2309 }
2311 /* Push a binding level here in case variables are declared as we want
2312 them to be local to this set of statements instead of to the block
2313 containing the Case statement. */
2315 {
2320 {
2325 }
2326 }
2327 }
2329 /* Now emit a definition of the label the cases branch to, if any. */
2336 }
2337 \f
2338 /* Find out whether VAR is an iteration variable of an enclosing loop in the
2339 current function. If so, push a range_check_info structure onto the stack
2340 of this enclosing loop and return it. Otherwise, return NULL. */
2344 {
2361 i--)
2366 {
2370 }
2373 }
2375 /* Return true if VAL (of type TYPE) can equal the minimum value if MAX is
2376 false, or the maximum value if MAX is true, of TYPE. */
2378 static bool
2380 {
2387 val = (max
2395 }
2397 /* Return true if VAL (of type TYPE) can equal the minimum value of TYPE.
2398 If REVERSE is true, minimum value is taken as maximum value. */
2402 {
2404 }
2406 /* Return true if VAL (of type TYPE) can equal the maximum value of TYPE.
2407 If REVERSE is true, maximum value is taken as minimum value. */
2411 {
2413 }
2415 /* Return true if VAL1 can be lower than VAL2. */
2417 static bool
2419 {
2433 }
2435 /* Subroutine of gnat_to_gnu to translate gnat_node, an N_Loop_Statement,
2436 to a GCC tree, which is returned. */
2438 static tree
2440 {
2447 tree gnu_result;
2449 /* Push the loop_info structure associated with the LOOP_STMT. */
2452 /* Set location information for statement and end label. */
2458 /* Save the statement for later reuse. */
2461 /* Set the condition under which the loop must keep going.
2462 For the case "LOOP .... END LOOP;" the condition is always true. */
2464 ;
2466 /* For the case "WHILE condition LOOP ..... END LOOP;" it's immediate. */
2471 /* Otherwise we have an iteration scheme and the condition is given by the
2472 bounds of the subtype of the iteration variable. */
2473 else
2474 {
2488 /* We must disable modulo reduction for the iteration variable, if any,
2489 in order for the loop comparison to be effective. */
2491 {
2497 }
2498 else
2499 {
2505 }
2507 /* We use two different strategies to translate the loop, depending on
2508 whether optimization is enabled.
2510 If it is, we generate the canonical loop form expected by the loop
2511 optimizer and the loop vectorizer, which is the do-while form:
2513 ENTRY_COND
2514 loop:
2515 TOP_UPDATE
2516 BODY
2517 BOTTOM_COND
2518 GOTO loop
2520 This avoids an implicit dependency on loop header copying and makes
2521 it possible to turn BOTTOM_COND into an inequality test.
2523 If optimization is disabled, loop header copying doesn't come into
2524 play and we try to generate the loop form with the fewer conditional
2525 branches. First, the default form, which is:
2527 loop:
2528 TOP_COND
2529 BODY
2530 BOTTOM_UPDATE
2531 GOTO loop
2533 It should catch most loops with constant ending point. Then, if we
2534 cannot, we try to generate the shifted form:
2536 loop:
2537 TOP_COND
2538 TOP_UPDATE
2539 BODY
2540 GOTO loop
2542 which should catch loops with constant starting point. Otherwise, if
2543 we cannot, we generate the fallback form:
2545 ENTRY_COND
2546 loop:
2547 BODY
2548 BOTTOM_COND
2549 BOTTOM_UPDATE
2550 GOTO loop
2552 which works in all cases. */
2555 {
2556 /* We can use the do-while form directly if GNU_FIRST-1 doesn't
2557 overflow. */
2559 ;
2561 /* Otherwise, use the do-while form with the help of a special
2562 induction variable in the unsigned version of the base type
2563 or the unsigned version of the size type, whichever is the
2564 largest, in order to have wrap-around arithmetics for it. */
2565 else
2566 {
2569 gnu_base_type
2571 else
2578 }
2580 gnu_first
2582 gnu_one_node);
2585 }
2586 else
2587 {
2588 /* We can use the default form if GNU_LAST+1 doesn't overflow. */
2590 ;
2592 /* Otherwise, we can use the shifted form if neither GNU_FIRST-1 nor
2593 GNU_LAST-1 does. */
2596 {
2597 gnu_first
2599 gnu_one_node);
2600 gnu_last
2602 gnu_one_node);
2604 }
2606 /* Otherwise, use the fallback form. */
2607 else
2609 }
2611 /* If we use the BOTTOM_COND, we can turn the test into an inequality
2612 test but we may have to add ENTRY_COND to protect the empty loop. */
2614 {
2617 {
2618 gnu_cond_expr
2624 }
2625 }
2627 /* Open a new nesting level that will surround the loop to declare the
2628 iteration variable. */
2632 /* If we use the special induction variable, create it and set it to
2633 its initial value. Morever, the regular iteration variable cannot
2634 itself be initialized, lest the initial value wrapped around. */
2636 {
2637 gnu_loop_iv
2641 }
2642 else
2645 /* Declare the iteration variable and set it to its initial value. */
2650 {
2653 }
2656 /* Do all the arithmetics in the base type. */
2659 /* Set either the top or bottom exit condition. */
2663 gnu_last);
2664 else
2667 gnu_last);
2669 /* Set either the top or bottom update statement and give it the source
2670 location of the iteration for better coverage info. */
2672 {
2673 gnu_stmt
2680 gnu_stmt
2682 gnu_loop_iv);
2686 }
2687 else
2688 {
2689 gnu_stmt
2695 }
2696 }
2698 /* If the loop was named, have the name point to this loop. In this case,
2699 the association is not a DECL node, but the end label of the loop. */
2703 /* Make the loop body into its own block, so any allocated storage will be
2704 released every iteration. This is needed for stack allocation. */
2709 /* If we have an iteration scheme, then we are in a statement group. Add
2710 the LOOP_STMT to it, finish it and make it the "loop". */
2712 {
2717 /* First, if we have computed a small number of invariant conditions for
2718 range checks applied to the iteration variable, then initialize these
2719 conditions in front of the loop. Otherwise, leave them set to True.
2721 ??? The heuristics need to be improved, by taking into account the
2722 following datapoints:
2723 - loop unswitching is disabled for big loops. The cap is the
2724 parameter PARAM_MAX_UNSWITCH_INSNS (50).
2725 - loop unswitching can only be applied a small number of times
2726 to a given loop. The cap is PARAM_MAX_UNSWITCH_LEVEL (3).
2727 - the front-end quickly generates useless or redundant checks
2728 that can be entirely optimized away in the end. */
2732 i++)
2733 {
2734 tree low_ok
2741 tree high_ok
2748 tree range_ok
2756 }
2761 }
2763 /* If we have an outer COND_EXPR, that's our result and this loop is its
2764 "true" statement. Otherwise, the result is the LOOP_STMT. */
2766 {
2770 }
2771 else
2777 }
2778 \f
2779 /* Emit statements to establish __gnat_handle_vms_condition as a VMS condition
2780 handler for the current function. */
2782 /* This is implemented by issuing a call to the appropriate VMS specific
2783 builtin. To avoid having VMS specific sections in the global gigi decls
2784 array, we maintain the decls of interest here. We can't declare them
2785 inside the function because we must mark them never to be GC'd, which we
2786 can only do at the global level. */
2791 static void
2793 {
2794 tree establish_stmt;
2796 /* Elaborate the required decls on the first call. Check on the decl for
2797 the gnat condition handler to decide, as this is one we create so we are
2798 sure that it will be non null on subsequent calls. The builtin decl is
2799 looked up so remains null on targets where it is not implemented yet. */
2801 {
2802 vms_builtin_establish_handler_decl
2803 = builtin_decl_for
2806 gnat_vms_condition_handler_decl
2808 NULL_TREE,
2810 ptr_void_type_node,
2811 ptr_void_type_node,
2812 NULL_TREE),
2814 Empty);
2816 /* ??? DECL_CONTEXT shouldn't have been set because of DECL_EXTERNAL. */
2818 }
2820 /* Do nothing if the establish builtin is not available, which might happen
2821 on targets where the facility is not implemented. */
2825 establish_stmt
2827 build_unary_op
2829 gnat_vms_condition_handler_decl));
2832 }
2834 /* This page implements a form of Named Return Value optimization modelled
2835 on the C++ optimization of the same name. The main difference is that
2836 we disregard any semantical considerations when applying it here, the
2837 counterpart being that we don't try to apply it to semantically loaded
2838 return types, i.e. types with the TYPE_BY_REFERENCE_P flag set.
2840 We consider a function body of the following GENERIC form:
2842 return_type R1;
2843 [...]
2844 RETURN_EXPR [<retval> = ...]
2845 [...]
2846 RETURN_EXPR [<retval> = R1]
2847 [...]
2848 return_type Ri;
2849 [...]
2850 RETURN_EXPR [<retval> = ...]
2851 [...]
2852 RETURN_EXPR [<retval> = Ri]
2853 [...]
2855 and we try to fulfill a simple criterion that would make it possible to
2856 replace one or several Ri variables with the RESULT_DECL of the function.
2858 The first observation is that RETURN_EXPRs that don't directly reference
2859 any of the Ri variables on the RHS of their assignment are transparent wrt
2860 the optimization. This is because the Ri variables aren't addressable so
2861 any transformation applied to them doesn't affect the RHS; moreover, the
2862 assignment writes the full <retval> object so existing values are entirely
2863 discarded.
2865 This property can be extended to some forms of RETURN_EXPRs that reference
2866 the Ri variables, for example CONSTRUCTORs, but isn't true in the general
2867 case, in particular when function calls are involved.
2869 Therefore the algorithm is as follows:
2871 1. Collect the list of candidates for a Named Return Value (Ri variables
2872 on the RHS of assignments of RETURN_EXPRs) as well as the list of the
2873 other expressions on the RHS of such assignments.
2875 2. Prune the members of the first list (candidates) that are referenced
2876 by a member of the second list (expressions).
2878 3. Extract a set of candidates with non-overlapping live ranges from the
2879 first list. These are the Named Return Values.
2881 4. Adjust the relevant RETURN_EXPRs and replace the occurrences of the
2882 Named Return Values in the function with the RESULT_DECL.
2884 If the function returns an unconstrained type, things are a bit different
2885 because the anonymous return object is allocated on the secondary stack
2886 and RESULT_DECL is only a pointer to it. Each return object can be of a
2887 different size and is allocated separately so we need not care about the
2888 aforementioned overlapping issues. Therefore, we don't collect the other
2889 expressions and skip step #2 in the algorithm. */
2891 struct nrv_data
2892 {
2893 bitmap nrv;
2894 tree result;
2895 Node_Id gnat_ret;
2897 };
2899 /* Return true if T is a Named Return Value. */
2903 {
2905 }
2907 /* Helper function for walk_tree, used by finalize_nrv below. */
2909 static tree
2911 {
2915 /* No need to walk into types or decls. */
2923 }
2925 /* Prune Named Return Values in BLOCK and return true if there is still a
2926 Named Return Value in BLOCK or one of its sub-blocks. */
2928 static bool
2930 {
2932 tree t;
2934 /* First recurse on the sub-blocks. */
2938 /* Then make sure to keep at most one NRV per block. */
2941 {
2944 else
2946 }
2949 }
2951 /* Helper function for walk_tree, used by finalize_nrv below. */
2953 static tree
2955 {
2959 /* No need to walk into types. */
2963 /* Change RETURN_EXPRs of NRVs to just refer to the RESULT_DECL; this is a
2964 nop, but differs from using NULL_TREE in that it indicates that we care
2965 about the value of the RESULT_DECL. */
2968 {
2971 /* If this is the temporary created for a return value with variable
2972 size in Call_to_gnu, we replace the RHS with the init expression. */
2977 {
2980 }
2981 else
2984 /* Strip useless conversions around the return value. */
2989 {
2992 else
2994 }
2995 }
2997 /* Replace the DECL_EXPR of NRVs with an initialization of the RESULT_DECL,
2998 if needed. */
3001 {
3005 {
3010 }
3011 else
3015 /* Identify the NRV to the RESULT_DECL for debugging purposes. */
3018 /* ??? Kludge to avoid an assertion failure during inlining. */
3021 }
3023 /* And replace all uses of NRVs with the RESULT_DECL. */
3027 /* Avoid walking into the same tree more than once. Unfortunately, we
3028 can't just use walk_tree_without_duplicates because it would only
3029 call us for the first occurrence of NRVs in the function body. */
3034 }
3036 /* Likewise, but used when the function returns an unconstrained type. */
3038 static tree
3040 {
3044 /* No need to walk into types. */
3048 /* We need to see the DECL_EXPR of NRVs before any other references so we
3049 walk the body of BIND_EXPR before walking its variables. */
3053 /* Change RETURN_EXPRs of NRVs to assign to the RESULT_DECL only the final
3054 return value built by the allocator instead of the whole construct. */
3057 {
3060 /* This is the construct returned by the allocator. */
3063 {
3065 ret_val
3068 else
3070 }
3072 /* Strip useless conversions around the return value. */
3077 /* Strip unpadding around the return value. */
3082 /* Assign the new return value to the RESULT_DECL. */
3086 }
3088 /* Adjust the DECL_EXPR of NRVs to call the allocator and save the result
3089 into a new variable. */
3092 {
3099 /* Create an artificial context to build the allocation. */
3104 /* This will return a COMPOUND_EXPR with the allocation in the first
3105 arm and the final return value in the second arm. */
3112 /* The new variable is built as a reference to the allocated space. */
3113 new_var
3119 {
3120 /* The new initial value is a COMPOUND_EXPR with the allocation in
3121 the first arm and the value of P_ARRAY in the second arm. */
3127 /* Build a modified CONSTRUCTOR that references NEW_VAR. */
3135 }
3136 else
3137 {
3138 /* The new initial value is just the allocation. */
3141 }
3145 /* Destroy the artificial context and insert the new statements. */
3150 /* Chain NEW_VAR immediately after VAR and ignore the latter. */
3155 /* Save the new return value and the dereference of NEW_VAR. */
3159 /* ??? Kludge to avoid messing up during inlining. */
3161 }
3163 /* And replace all uses of NRVs with the dereference of NEW_VAR. */
3167 /* Avoid walking into the same tree more than once. Unfortunately, we
3168 can't just use walk_tree_without_duplicates because it would only
3169 call us for the first occurrence of NRVs in the function body. */
3174 }
3176 /* Finalize the Named Return Value optimization for FNDECL. The NRV bitmap
3177 contains the candidates for Named Return Value and OTHER is a list of
3178 the other return values. GNAT_RET is a representative return node. */
3180 static void
3182 {
3185 walk_tree_fn func;
3187 tree iter;
3189 /* We shouldn't be applying the optimization to return types that we aren't
3190 allowed to manipulate freely. */
3193 /* Prune the candidates that are referenced by other return values. */
3202 /* Prune also the candidates that are referenced by nested functions. */
3210 /* Extract a set of NRVs with non-overlapping live ranges. */
3214 /* Adjust the relevant RETURN_EXPRs and replace the occurrences of NRVs. */
3221 else
3225 }
3227 /* Return true if RET_VAL can be used as a Named Return Value for the
3228 anonymous return object RET_OBJ. */
3230 static bool
3232 {
3252 }
3254 /* Build a RETURN_EXPR. If RET_VAL is non-null, build a RETURN_EXPR around
3255 the assignment of RET_VAL to RET_OBJ. Otherwise build a bare RETURN_EXPR
3256 around RESULT_OBJ, which may be null in this case. */
3258 static tree
3260 {
3261 tree result_expr;
3264 {
3265 /* The gimplifier explicitly enforces the following invariant:
3267 RETURN_EXPR
3268 |
3269 MODIFY_EXPR
3270 / \
3271 / \
3272 RET_OBJ ...
3274 As a consequence, type consistency dictates that we use the type
3275 of the RET_OBJ as the operation type. */
3278 /* Convert the right operand to the operation type. Note that it's the
3279 same transformation as in the MODIFY_EXPR case of build_binary_op,
3280 with the assumption that the type cannot involve a placeholder. */
3286 /* If the function returns an aggregate type, find out whether this is
3287 a candidate for Named Return Value. If so, record it. Otherwise,
3288 if this is an expression of some kind, record it elsewhere. */
3294 {
3295 /* Recognize the temporary created for a return value with variable
3296 size in Call_to_gnu. We want to eliminate it if possible. */
3303 /* Strip useless conversions around the return value. */
3307 /* Now apply the test to the return value. */
3309 {
3313 }
3315 /* Note that we need not care about CONSTRUCTORs here, as they are
3316 totally transparent given the read-compose-write semantics of
3317 assignments from CONSTRUCTORs. */
3320 }
3321 }
3322 else
3326 }
3328 /* Build a stub for the subprogram specified by the GCC tree GNU_SUBPROG
3329 and the GNAT node GNAT_SUBPROG. */
3331 static void
3333 {
3341 /* Initialize the information structure for the function. */
3350 /* Loop over the parameters of the stub and translate any of them
3351 passed by descriptor into a by reference one. */
3354 gnu_stub_param;
3357 {
3359 {
3361 gnu_param
3363 gnu_stub_param,
3365 gnat_subprog);
3366 }
3367 else
3371 }
3373 /* Invoke the internal subprogram. */
3375 gnu_subprog);
3379 /* Propagate the return value, if any. */
3382 else
3384 gnu_subprog_call));
3389 }
3390 \f
3391 /* Subroutine of gnat_to_gnu to process gnat_node, an N_Subprogram_Body. We
3392 don't return anything. */
3394 static void
3396 {
3397 /* Defining identifier of a parameter to the subprogram. */
3398 Entity_Id gnat_param;
3399 /* The defining identifier for the subprogram body. Note that if a
3400 specification has appeared before for this body, then the identifier
3401 occurring in that specification will also be a defining identifier and all
3402 the calls to this subprogram will point to that specification. */
3403 Entity_Id gnat_subprog_id
3406 /* The FUNCTION_DECL node corresponding to the subprogram spec. */
3407 tree gnu_subprog_decl;
3408 /* Its RESULT_DECL node. */
3409 tree gnu_result_decl;
3410 /* Its FUNCTION_TYPE node. */
3411 tree gnu_subprog_type;
3412 /* The TYPE_CI_CO_LIST of its FUNCTION_TYPE node, if any. */
3413 tree gnu_cico_list;
3414 /* The entry in the CI_CO_LIST that represents a function return, if any. */
3416 tree gnu_result;
3420 /* If this is a generic object or if it has been eliminated,
3421 ignore it. */
3427 /* If this subprogram acts as its own spec, define it. Otherwise, just get
3428 the already-elaborated tree node. However, if this subprogram had its
3429 elaboration deferred, we will already have made a tree node for it. So
3430 treat it as not being defined in that case. Such a subprogram cannot
3431 have an address clause or a freeze node, so this test is safe, though it
3432 does disable some otherwise-useful error checking. */
3433 gnu_subprog_decl
3443 /* If the function returns by invisible reference, make it explicit in the
3444 function body. See gnat_to_gnu_entity, E_Subprogram_Type case.
3445 Handle the explicit case here and the copy-in/copy-out case below. */
3447 {
3451 }
3453 /* Set the line number in the decl to correspond to that of the body so that
3454 the line number notes are written correctly. */
3457 /* Initialize the information structure for the function. */
3465 /* If there are In Out or Out parameters, we need to ensure that the return
3466 statement properly copies them out. We do this by making a new block and
3467 converting any return into a goto to a label at the end of the block. */
3469 {
3478 /* If this is a function with In Out or Out parameters, we also need a
3479 variable for the return value to be placed. */
3481 {
3482 tree gnu_return_type
3485 /* If the function returns by invisible reference, make it
3486 explicit in the function body. See gnat_to_gnu_entity,
3487 E_Subprogram_Type case. */
3491 gnu_return_var
3496 }
3500 /* See whether there are parameters for which we don't have a GCC tree
3501 yet. These must be Out parameters. Make a VAR_DECL for them and
3502 put it into TYPE_CI_CO_LIST, which must contain an empty entry too.
3503 We can match up the entries because TYPE_CI_CO_LIST is in the order
3504 of the parameters. */
3509 {
3511 tree gnu_decl;
3513 /* Skip any entries that have been already filled in; they must
3514 correspond to In Out parameters. */
3518 /* Do any needed dereferences for by-ref objects. */
3524 /* Do any needed references for padded types. */
3527 }
3528 }
3529 else
3532 /* Get a tree corresponding to the code for the subprogram. */
3536 /* On VMS, establish our condition handler to possibly turn a condition into
3537 the corresponding exception if the subprogram has a foreign convention or
3538 is exported.
3540 To ensure proper execution of local finalizations on condition instances,
3541 we must turn a condition into the corresponding exception even if there
3542 is no applicable Ada handler, and need at least one condition handler per
3543 possible call chain involving GNAT code. OTOH, establishing the handler
3544 has a cost so we want to minimize the number of subprograms into which
3545 this happens. The foreign or exported condition is expected to satisfy
3546 all the constraints. */
3554 /* Generate the code of the subprogram itself. A return statement will be
3555 present and any Out parameters will be handled there. */
3560 /* If we populated the parameter attributes cache, we need to make sure that
3561 the cached expressions are evaluated on all the possible paths leading to
3562 their uses. So we force their evaluation on entry of the function. */
3565 {
3572 {
3579 }
3585 }
3587 /* If we are dealing with a return from an Ada procedure with parameters
3588 passed by copy-in/copy-out, we need to return a record containing the
3589 final values of these parameters. If the list contains only one entry,
3590 return just that entry though.
3592 For a full description of the copy-in/copy-out parameter mechanism, see
3593 the part of the gnat_to_gnu_entity routine dealing with the translation
3594 of subprograms.
3596 We need to make a block that contains the definition of that label and
3597 the copying of the return value. It first contains the function, then
3598 the label and copy statement. */
3600 {
3601 tree gnu_retval;
3609 else
3611 gnu_cico_list);
3617 }
3621 /* Attempt setting the end_locus of our GCC body tree, typically a
3622 BIND_EXPR or STATEMENT_LIST, then the end_locus of our GCC subprogram
3623 declaration tree. */
3627 /* On SEH targets, install an exception handler around the main entry
3628 point to catch unhandled exceptions. */
3631 {
3632 tree t;
3633 tree etype;
3645 }
3649 /* Finally annotate the parameters and disconnect the trees for parameters
3650 that we have turned into variables since they are now unusable. */
3654 {
3663 }
3665 /* Disconnect the variable created for the return value. */
3669 /* If the function returns an aggregate type and we have candidates for
3670 a Named Return Value, finalize the optimization. */
3672 {
3679 }
3683 /* If there is a stub associated with the function, build it now. */
3686 }
3687 \f
3688 /* Return true if GNAT_NODE requires atomic synchronization. */
3690 static bool
3692 {
3694 Node_Kind kind;
3697 /* First, scan the node to find the Atomic_Sync_Required flag. */
3700 {
3703 }
3706 {
3718 }
3720 /* Then, scan the parent to find out cases where the flag is irrelevant. */
3723 {
3726 /* Do not mess up machine code insertions. */
3732 /* Do not generate a function call as a renamed object. */
3737 }
3740 }
3741 \f
3742 /* Create a temporary variable with PREFIX and TYPE, and return it. */
3744 static tree
3746 {
3754 }
3756 /* Create a temporary variable with PREFIX and initialize it with GNU_INIT.
3757 Put the initialization statement into GNU_INIT_STMT and annotate it with
3758 the SLOC of GNAT_NODE. Return the temporary variable. */
3760 static tree
3762 Node_Id gnat_node)
3763 {
3770 }
3772 /* Subroutine of gnat_to_gnu to translate gnat_node, either an N_Function_Call
3773 or an N_Procedure_Call_Statement, to a GCC tree, which is returned.
3774 GNU_RESULT_TYPE_P is a pointer to where we should place the result type.
3775 If GNU_TARGET is non-null, this must be a function call on the RHS of a
3776 N_Assignment_Statement and the result is to be placed into that object.
3777 If, in addition, ATOMIC_SYNC is true, then the assignment to GNU_TARGET
3778 requires atomic synchronization. */
3780 static tree
3783 {
3786 /* The GCC node corresponding to the GNAT subprogram name. This can either
3787 be a FUNCTION_DECL node if we are dealing with a standard subprogram call,
3788 or an indirect reference expression (an INDIRECT_REF node) pointing to a
3789 subprogram. */
3791 /* The FUNCTION_TYPE node giving the GCC type of the subprogram. */
3793 /* The return type of the FUNCTION_TYPE. */
3804 Entity_Id gnat_formal;
3805 Node_Id gnat_actual;
3809 /* If we are calling a stubbed function, raise Program_Error, but Elaborate
3810 all our args first. */
3812 {
3822 {
3825 }
3828 }
3830 /* The only way we can be making a call via an access type is if Name is an
3831 explicit dereference. In that case, get the list of formal args from the
3832 type the access type is pointing to. Otherwise, get the formals from the
3833 entity being called. */
3837 /* Assume here that this must be 'Elab_Body or 'Elab_Spec. */
3839 else
3842 /* The lifetime of the temporaries created for the call ends right after the
3843 return value is copied, so we can give them the scope of the elaboration
3844 routine at top level. */
3846 {
3849 }
3851 /* First, create the temporary for the return value when:
3853 1. There is no target and the function has copy-in/copy-out parameters,
3854 because we need to preserve the return value before copying back the
3855 parameters.
3857 2. There is no target and this is not an object declaration, and the
3858 return type has variable size, because in these cases the gimplifier
3859 cannot create the temporary.
3861 3. There is a target and it is a slice or an array with fixed size,
3862 and the return type has variable size, because the gimplifier
3863 doesn't handle these cases.
3865 This must be done before we push a binding level around the call, since
3866 we will pop it before copying the return value. */
3869 || (!gnu_target
3872 || (gnu_target
3880 /* Create the list of the actual parameters as GCC expects it, namely a
3881 chain of TREE_LIST nodes in which the TREE_VALUE field of each node
3882 is an expression and the TREE_PURPOSE field is null. But skip Out
3883 parameters not passed by reference and that need not be copied in. */
3888 {
3892 const bool is_true_formal_parm
3894 const bool is_by_ref_formal_parm
3895 = is_true_formal_parm
3899 /* In the Out or In Out case, we must suppress conversions that yield
3900 an lvalue but can nevertheless cause the creation of a temporary,
3901 because we need the real object in this case, either to pass its
3902 address if it's passed by reference or as target of the back copy
3903 done after the call if it uses the copy-in/copy-out mechanism.
3904 We do it in the In case too, except for an unchecked conversion
3905 because it alone can cause the actual to be misaligned and the
3906 addressability test is applied to the real object. */
3907 const bool suppress_type_conversion
3912 Node_Id gnat_name = suppress_type_conversion
3915 tree gnu_actual;
3917 /* If it's possible we may need to use this expression twice, make sure
3918 that any side-effects are handled via SAVE_EXPRs; likewise if we need
3919 to force side-effects before the call.
3920 ??? This is more conservative than we need since we don't need to do
3921 this for pass-by-ref with no conversion. */
3925 /* If we are passing a non-addressable parameter by reference, pass the
3926 address of a copy. In the Out or In Out case, set up to copy back
3927 out after the call. */
3931 {
3935 /* Do not issue warnings for CONSTRUCTORs since this is not a copy
3936 but sort of an instantiation for them. */
3938 ;
3940 /* If the type is passed by reference, a copy is not allowed. */
3943 gnat_actual);
3945 /* For users of Starlet we issue a warning because the interface
3946 apparently assumes that by-ref parameters outlive the procedure
3947 invocation. The code still will not work as intended, but we
3948 cannot do much better since low-level parts of the back-end
3949 would allocate temporaries at will because of the misalignment
3950 if we did not do so here. */
3952 {
3953 post_error
3955 post_error_ne
3959 gnat_formal);
3960 }
3962 /* If the actual type of the object is already the nominal type,
3963 we have nothing to do, except if the size is self-referential
3964 in which case we'll remove the unpadding below. */
3967 ;
3969 /* Otherwise remove the unpadding from all the objects. */
3971 && TYPE_IS_PADDING_P
3975 /* Otherwise convert to the nominal type of the object if needed.
3976 There are several cases in which we need to make the temporary
3977 using this type instead of the actual type of the object when
3978 they are distinct, because the expectations of the callee would
3979 otherwise not be met:
3980 - if it's a justified modular type,
3981 - if the actual type is a smaller form of it,
3982 - if it's a smaller form of the actual type. */
3986 gnu_name_type)))
3992 /* If this is an In Out or Out parameter and we're returning a value,
3993 we need to create a temporary for the return value because we must
3994 preserve it before copying back at the very end. */
3998 /* If we haven't pushed a binding level, push a new one. This will
3999 narrow the lifetime of the temporary we are about to make as much
4000 as possible. The drawback is that we'd need to create a temporary
4001 for the return value, if any (see comment before the loop). So do
4002 it only when this temporary was already created just above. */
4004 {
4008 }
4010 /* Create an explicit temporary holding the copy. */
4011 gnu_temp
4014 /* But initialize it on the fly like for an implicit temporary as
4015 we aren't necessarily having a statement list. */
4017 gnu_temp);
4019 /* Set up to move the copy back to the original if needed. */
4021 {
4023 gnu_temp);
4026 }
4027 }
4029 /* Start from the real object and build the actual. */
4032 /* If this is an atomic access of an In or In Out parameter for which
4033 synchronization is required, build the atomic load. */
4035 && !is_by_ref_formal_parm
4040 /* If this was a procedure call, we may not have removed any padding.
4041 So do it here for the part we will use as an input, if any. */
4044 gnu_actual
4047 /* Put back the conversion we suppressed above in the computation of the
4048 real object. And even if we didn't suppress any conversion there, we
4049 may have suppressed a conversion to the Etype of the actual earlier,
4050 since the parent is a procedure call, so put it back here. */
4053 gnu_actual
4056 else
4057 gnu_actual
4060 /* Make sure that the actual is in range of the formal's type. */
4063 gnu_actual
4066 /* Unless this is an In parameter, we must remove any justified modular
4067 building from GNU_NAME to get an lvalue. */
4072 gnu_name
4075 /* If we have not saved a GCC object for the formal, it means it is an
4076 Out parameter not passed by reference and that need not be copied in.
4077 Otherwise, first see if the parameter is passed by reference. */
4079 {
4081 {
4082 /* In Out or Out parameters passed by reference don't use the
4083 copy-in/copy-out mechanism so the address of the real object
4084 must be passed to the function. */
4087 /* If we have a padded type, be sure we've removed padding. */
4090 gnu_actual);
4092 /* If we have the constructed subtype of an aliased object
4093 with an unconstrained nominal subtype, the type of the
4094 actual includes the template, although it is formally
4095 constrained. So we need to convert it back to the real
4096 constructed subtype to retrieve the constrained part
4097 and takes its address. */
4103 gnu_actual);
4104 }
4106 /* There is no need to convert the actual to the formal's type before
4107 taking its address. The only exception is for unconstrained array
4108 types because of the way we build fat pointers. */
4110 {
4111 /* Put back a view conversion for In Out or Out parameters. */
4114 gnu_actual);
4116 }
4118 /* The symmetry of the paths to the type of an entity is broken here
4119 since arguments don't know that they will be passed by ref. */
4122 }
4124 {
4130 {
4133 }
4135 /* Take the address of the object and convert to the proper pointer
4136 type. We'd like to actually compute the address of the beginning
4137 of the array using an ADDR_EXPR of an ARRAY_REF, but there's a
4138 possibility that the ARRAY_REF might return a constant and we'd be
4139 getting the wrong address. Neither approach is exactly correct,
4140 but this is the most likely to work in all cases. */
4142 }
4144 {
4147 /* If this is 'Null_Parameter, pass a zero descriptor. */
4151 gnu_actual
4153 else
4155 fill_vms_descriptor
4158 }
4159 else
4160 {
4161 tree gnu_size;
4167 {
4168 /* Make sure side-effects are evaluated before the call. */
4172 }
4176 /* If this is 'Null_Parameter, pass a zero even though we are
4177 dereferencing it. */
4183 gnu_actual
4187 integer_zero_node),
4189 else
4191 }
4194 }
4196 gnu_call
4200 /* If we have created a temporary for the return value, initialize it. */
4202 {
4203 tree gnu_stmt
4208 }
4210 /* If this is a subprogram with copy-in/copy-out parameters, we need to
4211 unpack the valued returned from the function into the In Out or Out
4212 parameters. We deal with the function return (if this is an Ada
4213 function) below. */
4215 {
4216 /* List of FIELD_DECLs associated with the PARM_DECLs of the copy-in/
4217 copy-out parameters. */
4221 /* The call sequence must contain one and only one call, even though the
4222 function is pure. Save the result into a temporary if needed. */
4224 {
4226 {
4227 tree gnu_stmt;
4228 /* If we haven't pushed a binding level, push a new one. This
4229 will narrow the lifetime of the temporary we are about to
4230 make as much as possible. */
4232 {
4236 }
4237 gnu_call
4240 }
4243 }
4245 /* The first entry is for the actual return value if this is a
4246 function, so skip it. */
4252 else
4259 /* If we are dealing with a copy-in/copy-out parameter, we must
4260 retrieve its value from the record returned in the call. */
4266 || (DECL_BY_DESCRIPTOR_P
4269 {
4270 /* Get the value to assign to this Out or In Out parameter. It is
4271 either the result of the function if there is only a single such
4272 parameter or the appropriate field from the record returned. */
4273 tree gnu_result
4275 ? gnu_call
4279 /* If the actual is a conversion, get the inner expression, which
4280 will be the real destination, and convert the result to the
4281 type of the actual parameter. */
4282 tree gnu_actual
4285 /* If the result is a padded type, remove the padding. */
4287 gnu_result
4289 gnu_result);
4291 /* If the actual is a type conversion, the real target object is
4292 denoted by the inner Expression and we need to convert the
4293 result to the associated type.
4294 We also need to convert our gnu assignment target to this type
4295 if the corresponding GNU_NAME was constructed from the GNAT
4296 conversion node and not from the inner Expression. */
4298 {
4299 gnu_result
4300 = convert_with_check
4308 }
4310 /* Unchecked conversions as actuals for Out parameters are not
4311 allowed in user code because they are not variables, but do
4312 occur in front-end expansions. The associated GNU_NAME is
4313 always obtained from the inner expression in such cases. */
4316 gnu_result,
4318 else
4319 {
4321 gnu_result
4323 gnat_actual);
4328 }
4332 else
4339 }
4340 }
4342 /* If this is a function call, the result is the call expression unless a
4343 target is specified, in which case we copy the result into the target
4344 and return the assignment statement. */
4346 {
4347 /* If this is a function with copy-in/copy-out parameters, extract the
4348 return value from it and update the return type. */
4350 {
4355 }
4357 /* If the function returns an unconstrained array or by direct reference,
4358 we have to dereference the pointer. */
4364 {
4368 /* If range check is needed, emit code to generate it. */
4370 gnu_call
4372 gnat_parent);
4374 /* ??? If the return type has variable size, then force the return
4375 slot optimization as we would not be able to create a temporary.
4376 Likewise if it was unconstrained as we would copy too much data.
4377 That's what has been done historically. */
4380 && CONTAINS_PLACEHOLDER_P
4383 else
4388 else
4389 gnu_call
4393 }
4394 else
4396 }
4398 /* Otherwise, if this is a procedure call statement without copy-in/copy-out
4399 parameters, the result is just the call statement. */
4403 /* Finally, add the copy back statements, if any. */
4409 /* If we have pushed a binding level, pop it and finish up the enclosing
4410 statement group. */
4412 {
4416 }
4418 /* Otherwise, retrieve the statement list, if any. */
4422 /* Otherwise, just return the call expression. */
4423 else
4426 /* If we nevertheless need a value, make a COMPOUND_EXPR to return it.
4427 But first simplify if we have only one statement in the list. */
4429 {
4433 gnu_result
4435 }
4438 }
4439 \f
4440 /* Subroutine of gnat_to_gnu to translate gnat_node, an
4441 N_Handled_Sequence_Of_Statements, to a GCC tree, which is returned. */
4443 static tree
4445 {
4448 /* If just annotating, ignore all EH and cleanups. */
4452 bool setjmp_longjmp
4458 tree gnu_result;
4459 tree gnu_expr;
4460 Node_Id gnat_temp;
4462 /* The GCC exception handling mechanism can handle both ZCX and SJLJ schemes
4463 and we have our own SJLJ mechanism. To call the GCC mechanism, we call
4464 add_cleanup, and when we leave the binding, end_stmt_group will create
4465 the TRY_FINALLY_EXPR.
4467 ??? The region level calls down there have been specifically put in place
4468 for a ZCX context and currently the order in which things are emitted
4469 (region/handlers) is different from the SJLJ case. Instead of putting
4470 other calls with different conditions at other places for the SJLJ case,
4471 it seems cleaner to reorder things for the SJLJ case and generalize the
4472 condition to make it not ZCX specific.
4474 If there are any exceptions or cleanup processing involved, we need an
4475 outer statement group (for Setjmp_Longjmp) and binding level. */
4477 {
4480 }
4482 /* If using setjmp_longjmp, make the variables for the setjmp buffer and save
4483 area for address of previous buffer. Do this first since we need to have
4484 the setjmp buf known for any decls in this block. */
4486 {
4487 gnu_jmpsave_decl
4489 jmpbuf_ptr_type,
4494 /* The __builtin_setjmp receivers will immediately reinstall it. Now
4495 because of the unstructured form of EH used by setjmp_longjmp, there
4496 might be forward edges going to __builtin_setjmp receivers on which
4497 it is uninitialized, although they will never be actually taken. */
4499 gnu_jmpbuf_decl
4501 jmpbuf_type,
4502 NULL_TREE,
4508 /* When we exit this block, restore the saved value. */
4511 }
4513 /* If we are to call a function when exiting this block, add a cleanup
4514 to the binding level we made above. Note that add_cleanup is FIFO
4515 so we must register this cleanup after the EH cleanup just above. */
4520 /* Now build the tree for the declarations and statements inside this block.
4521 If this is SJLJ, set our jmp_buf as the current buffer. */
4527 gnu_jmpbuf_decl)));
4533 /* Generate code for each statement in the block. */
4541 /* Now generate code for the two exception models, if either is relevant for
4542 this block. */
4544 {
4546 tree gnu_handler;
4548 /* Make a binding level for the exception handling declarations and code
4549 and set up gnu_except_ptr_stack for the handlers to use. */
4560 /* Generate code for each handler. The N_Exception_Handler case does the
4561 real work and returns a COND_EXPR for each handler, which we chain
4562 together here. */
4565 {
4568 /* If this is the first one, set it as the outer one. Otherwise,
4569 point the "else" part of the previous handler to us. Then point
4570 to our "else" part. */
4573 else
4577 }
4579 /* If none of the exception handlers did anything, re-raise but do not
4580 defer abortion. */
4583 set_expr_location_from_node
4589 else
4592 /* End the binding level dedicated to the exception handlers and get the
4593 whole statement group. */
4598 /* If the setjmp returns 1, we restore our incoming longjmp value and
4599 then check the handlers. */
4602 gnu_jmpsave_decl),
4603 gnat_node);
4607 /* This block is now "if (setjmp) ... <handlers> else <block>". */
4609 (build_call_n_expr
4612 gnu_jmpbuf_decl))),
4614 }
4616 {
4617 tree gnu_handlers;
4618 location_t locus;
4620 /* First make a block containing the handlers. */
4628 /* Now make the TRY_CATCH_EXPR for the block. */
4631 /* Set a location. We need to find a uniq location for the dispatching
4632 code, otherwise we can get coverage or debugging issues. Try with
4633 the location of the end label. */
4637 else
4639 }
4640 else
4643 /* Now close our outer block, if we had to make one. */
4645 {
4649 }
4652 }
4653 \f
4654 /* Subroutine of gnat_to_gnu to translate gnat_node, an N_Exception_Handler,
4655 to a GCC tree, which is returned. This is the variant for Setjmp_Longjmp
4656 exception handling. */
4658 static tree
4660 {
4661 /* Unless this is "Others" or the special "Non-Ada" exception for Ada, make
4662 an "if" statement to select the proper exceptions. For "Others", exclude
4663 exceptions where Handled_By_Others is nonzero unless the All_Others flag
4664 is set. For "Non-ada", accept an exception if "Lang" is 'V'. */
4667 Node_Id gnat_temp;
4671 {
4672 tree this_choice;
4675 {
4678 else
4679 this_choice
4680 = build_binary_op
4682 convert
4684 build_component_ref
4685 (build_unary_op
4690 integer_zero_node);
4691 }
4695 {
4697 tree gnu_expr;
4699 /* Exception may be a renaming. Recover original exception which is
4700 the one elaborated and registered. */
4706 this_choice
4707 = build_binary_op
4713 /* If this is the distinguished exception "Non_Ada_Error" (and we are
4714 in VMS mode), also allow a non-Ada exception (a VMS condition) t
4715 match. */
4717 {
4718 tree gnu_comp
4719 = build_component_ref
4724 this_choice
4725 = build_binary_op
4729 this_choice);
4730 }
4731 }
4732 else
4737 }
4740 }
4741 \f
4742 /* Subroutine of gnat_to_gnu to translate gnat_node, an N_Exception_Handler,
4743 to a GCC tree, which is returned. This is the variant for ZCX. */
4745 static tree
4747 {
4749 tree gnu_expr;
4750 tree gnu_etype;
4751 tree gnu_current_exc_ptr;
4752 tree prev_gnu_incoming_exc_ptr;
4753 Node_Id gnat_temp;
4755 /* We build a TREE_LIST of nodes representing what exception types this
4756 handler can catch, with special cases for others and all others cases.
4758 Each exception type is actually identified by a pointer to the exception
4759 id, or to a dummy object for "others" and "all others". */
4762 {
4764 {
4765 tree gnu_expr
4768 gnu_etype
4770 }
4773 {
4776 /* Exception may be a renaming. Recover original exception which is
4777 the one elaborated and registered. */
4784 /* The Non_Ada_Error case for VMS exceptions is handled
4785 by the personality routine. */
4786 }
4787 else
4790 /* The GCC interface expects NULL to be passed for catch all handlers, so
4791 it would be quite tempting to set gnu_etypes_list to NULL if gnu_etype
4792 is integer_zero_node. It would not work, however, because GCC's
4793 notion of "catch all" is stronger than our notion of "others". Until
4794 we correctly use the cleanup interface as well, doing that would
4795 prevent the "all others" handlers from being seen, because nothing
4796 can be caught beyond a catch all from GCC's point of view. */
4798 }
4803 /* Expand a call to the begin_handler hook at the beginning of the handler,
4804 and arrange for a call to the end_handler hook to occur on every possible
4805 exit path.
4807 The hooks expect a pointer to the low level occurrence. This is required
4808 for our stack management scheme because a raise inside the handler pushes
4809 a new occurrence on top of the stack, which means that this top does not
4810 necessarily match the occurrence this handler was dealing with.
4812 __builtin_eh_pointer references the exception occurrence being
4813 propagated. Upon handler entry, this is the exception for which the
4814 handler is triggered. This might not be the case upon handler exit,
4815 however, as we might have a new occurrence propagated by the handler's
4816 body, and the end_handler hook called as a cleanup in this context.
4818 We use a local variable to retrieve the incoming value at handler entry
4819 time, and reuse it to feed the end_handler hook's argument at exit. */
4821 gnu_current_exc_ptr
4831 gnu_incoming_exc_ptr),
4832 gnat_node);
4833 /* ??? We don't seem to have an End_Label at hand to set the location. */
4835 Empty);
4843 }
4844 \f
4845 /* Subroutine of gnat_to_gnu to generate code for an N_Compilation unit. */
4847 static void
4849 {
4854 Node_Id gnat_pragma;
4855 /* Make the decl for the elaboration procedure. */
4856 tree gnu_elab_proc_decl
4857 = create_subprog_decl
4860 gnat_unit);
4866 /* Initialize the information structure for the function. */
4875 /* For a body, first process the spec if there is one. */
4881 {
4888 }
4890 /* Then process any pragmas and declarations preceding the unit. */
4899 /* Process the unit itself. */
4902 /* If we can inline, generate code for all the inlined subprograms. */
4904 {
4905 Entity_Id gnat_entity;
4910 {
4914 {
4915 /* ??? This really should always be present. */
4918 gnat_body
4920 }
4923 {
4924 /* Define the entity first so we set DECL_EXTERNAL. */
4927 }
4928 }
4929 }
4931 /* Process any pragmas and actions following the unit. */
4936 /* Save away what we've made so far and record this potential elaboration
4937 procedure. */
4950 /* Generate elaboration code for this unit, if necessary, and say whether
4951 we did or not. */
4954 /* Invalidate the global renaming pointers. This is necessary because
4955 stabilization of the renamed entities may create SAVE_EXPRs which
4956 have been tied to a specific elaboration routine just above. */
4958 }
4959 \f
4960 /* Subroutine of gnat_to_gnu to translate gnat_node, an N_Raise_xxx_Error,
4961 to a GCC tree, which is returned. GNU_RESULT_TYPE_P is a pointer to where
4962 we should place the result type. LABEL_P is true if there is a label to
4963 branch to for the exception. */
4965 static tree
4967 {
4971 const bool with_extra_info
4972 = Exception_Extra_Info
4980 {
4990 {
4996 {
5016 }
5023 && gnu_low_bound
5024 && gnu_high_bound
5027 gnu_result
5031 /* If loop unswitching is enabled, we try to compute invariant
5032 conditions for checks applied to iteration variables, i.e.
5033 conditions that are both independent of the variable and
5034 necessary in order for the check to fail in the course of
5035 some iteration, and prepend them to the original condition
5036 of the checks. This will make it possible later for the
5037 loop unswitching pass to replace the loop with two loops,
5038 one of which has the checks eliminated and the other has
5039 the original checks reinstated, and a run time selection.
5040 The former loop will be suitable for vectorization. */
5042 && (!gnu_low_bound
5044 && (!gnu_high_bound
5047 {
5052 boolean_true_node);
5054 boolean_type_node,
5057 }
5058 }
5063 }
5065 common:
5070 /* If the type is VOID, this is a statement, so we need to generate the code
5071 for the call. Handle a condition, if there is one. */
5073 {
5075 {
5080 }
5081 }
5082 else
5086 }
5087 \f
5088 /* Return true if GNAT_NODE is on the LHS of an assignment or an actual
5089 parameter of a call. */
5091 static bool
5093 {
5108 }
5110 /* Return true if either GNAT_NODE or a view of GNAT_NODE is on the LHS
5111 of an assignment or an actual parameter of a call. */
5113 static bool
5115 {
5116 Node_Kind kind;
5128 }
5130 /* Return true if GNAT_NODE, an unchecked type conversion, is a no-op as far
5131 as gigi is concerned. This is used to avoid conversions on the LHS. */
5133 static bool
5135 {
5138 /* The conversion must be on the LHS of an assignment or an actual parameter
5139 of a call. Otherwise, even if the conversion was essentially a no-op, it
5140 could de facto ensure type consistency and this should be preserved. */
5146 /* We're interested in artificial conversions generated by the front-end
5147 to make private types explicit, e.g. in Expand_Assign_Array. */
5154 /* The direct conversion to the underlying type is a no-op. */
5158 /* For an array subtype, the conversion to the PAT is a no-op. */
5163 /* For a record subtype, the conversion to the type is a no-op. */
5169 }
5171 /* This function is the driver of the GNAT to GCC tree transformation process.
5172 It is the entry point of the tree transformer. GNAT_NODE is the root of
5173 some GNAT tree. Return the root of the corresponding GCC tree. If this
5174 is an expression, return the GCC equivalent of the expression. If this
5175 is a statement, return the statement or add it to the current statement
5176 group, in which case anything returned is to be interpreted as occurring
5177 after anything added. */
5179 tree
5181 {
5187 Node_Id gnat_temp;
5189 /* Save node number for error message and set location information. */
5193 /* If this node is a statement and we are only annotating types, return an
5194 empty statement list. */
5198 /* If this node is a non-static subexpression and we are only annotating
5199 types, make this into a NULL_EXPR. */
5206 N_Raise_Constraint_Error));
5215 {
5218 /* If this is a statement and we are at top level, it must be part of
5219 the elaboration procedure, so mark us as being in that procedure. */
5221 {
5224 }
5226 /* If we are in the elaboration procedure, check if we are violating a
5227 No_Elaboration_Code restriction by having a statement there. Don't
5228 check for a possible No_Elaboration_Code restriction violation on
5229 N_Handled_Sequence_Of_Statements, as we want to signal an error on
5230 every nested real statement instead. This also avoids triggering
5231 spurious errors on dummy (empty) sequences created by the front-end
5232 for package bodies in some cases. */
5236 }
5239 {
5240 /********************************/
5241 /* Chapter 2: Lexical Elements */
5242 /********************************/
5250 /* If this is an atomic access on the RHS for which synchronization is
5251 required, build the atomic load. */
5258 {
5259 tree gnu_type;
5261 /* Get the type of the result, looking inside any padding and
5262 justified modular types. Then get the value in that type. */
5271 /* If the result overflows (meaning it doesn't fit in its base type),
5272 abort. We would like to check that the value is within the range
5273 of the subtype, but that causes problems with subtypes whose usage
5274 will raise Constraint_Error and with biased representation, so
5275 we don't. */
5277 }
5281 /* If a Entity is present, it means that this was one of the
5282 literals in a user-defined character type. In that case,
5283 just return the value in the CONST_DECL. Otherwise, use the
5284 character code. In that case, the base type should be an
5285 INTEGER_TYPE, but we won't bother checking for that. */
5289 else
5290 gnu_result
5291 = build_int_cst_type
5298 /* If this is of a fixed-point type, the value we want is the
5299 value of the corresponding integer. */
5301 {
5303 gnu_result_type);
5305 }
5307 /* Convert the Ureal to a vax float (represented on a signed type). */
5309 {
5311 gnu_result_type);
5312 }
5314 else
5315 {
5318 /* First convert the real value to a machine number if it isn't
5319 already. That forces BASE to 2 for non-zero values and simplifies
5320 the rest of our logic. */
5323 ur_realval
5329 else
5330 {
5331 REAL_VALUE_TYPE tmp;
5333 gnu_result
5336 /* The base must be 2 as Machine guarantees this, so we scale
5337 the value, which we know can fit in the mantissa of the type
5338 (hence the use of that type above). */
5344 }
5346 /* Now see if we need to negate the result. Do it this way to
5347 properly handle -0. */
5349 gnu_result
5351 gnu_result);
5352 }
5359 {
5366 else
5369 /* Build the string with the characters in the literal. Note
5370 that Ada strings are 1-origin. */
5374 /* Put a null at the end of the string in case it's in a context
5375 where GCC will want to treat it as a C string. */
5380 /* Strings in GCC don't normally have types, but we want
5381 this to not be converted to the array type. */
5386 }
5387 else
5388 {
5389 /* Build a list consisting of each character, then make
5390 the aggregate. */
5399 {
5405 }
5408 }
5415 /**************************************/
5416 /* Chapter 3: Declarations and Types */
5417 /**************************************/
5434 /* If we are just annotating types and this object has an unconstrained
5435 or task type, don't elaborate it. */
5445 && (!type_annotate_only
5447 {
5450 gnu_expr
5453 /* If this object has its elaboration delayed, we must force
5454 evaluation of GNU_EXPR right now and save it for when the object
5455 is frozen. */
5457 {
5459 ;
5461 gnu_expr
5466 else
5470 }
5471 }
5472 else
5478 /* If this is a deferred constant with an address clause, we ignore the
5479 full view since the clause is on the partial view and we cannot have
5480 2 different GCC trees for the object. The only bits of the full view
5481 we will use is the initializer, but it will be directly fetched. */
5494 /* Don't do anything if this renaming is handled by the front end or if
5495 we are just annotating types and this object has a composite or task
5496 type, don't elaborate it. We return the result in case it has any
5497 SAVE_EXPRs in it that need to be evaluated here. */
5499 && ! (type_annotate_only
5503 gnu_result
5506 else
5519 /* These are fully handled in the front end. */
5523 /*************************************/
5524 /* Chapter 4: Names and Expressions */
5525 /*************************************/
5532 /* If this is an atomic access on the RHS for which synchronization is
5533 required, build the atomic load. */
5540 {
5542 tree gnu_type;
5549 /* Convert vector inputs to their representative array type, to fit
5550 what the code below expects. */
5552 {
5556 }
5560 /* If we got a padded type, remove it too. */
5562 gnu_array_object
5564 gnu_array_object);
5568 /* The failure of this assertion will very likely come from a missing
5569 expansion for a packed array access. */
5572 /* First compute the number of dimensions of the array, then
5573 fill the expression array, the order depending on whether
5574 this is a Convention_Fortran array or not. */
5579 ;
5588 else
5596 {
5602 gnu_expr
5603 = emit_index_check
5607 gnat_temp);
5611 }
5615 /* If this is an atomic access on the RHS for which synchronization is
5616 required, build the atomic load. */
5620 }
5624 {
5626 tree gnu_type;
5631 /* Do any implicit dereferences of the prefix and do any needed
5632 range check. */
5637 {
5638 /* Get the bounds of the slice. */
5639 tree gnu_index_type
5643 /* Get the permitted bounds. */
5644 tree gnu_base_index_type
5646 tree gnu_base_min_expr = SUBSTITUTE_PLACEHOLDER_IN_EXPR
5648 tree gnu_base_max_expr = SUBSTITUTE_PLACEHOLDER_IN_EXPR
5655 /* Derive a good type to convert everything to. */
5658 /* Test whether the minimum slice value is too small. */
5661 gnu_min_expr),
5663 gnu_base_min_expr));
5665 /* Test whether the maximum slice value is too large. */
5668 gnu_max_expr),
5670 gnu_base_max_expr));
5672 /* Build a slice index check that returns the low bound,
5673 assuming the slice is not empty. */
5674 gnu_expr = emit_check
5679 /* Build a conditional expression that does the index checks and
5680 returns the low bound if the slice is not empty (max >= min),
5681 and returns the naked low bound otherwise (max < min), unless
5682 it is non-constant and the high bound is; this prevents VRP
5683 from inferring bogus ranges on the unlikely path. */
5687 gnu_max_expr),
5689 gnu_min_expr)),
5690 gnu_expr,
5694 }
5695 else
5696 /* Simply return the naked low bound. */
5699 /* If this is a slice with non-constant size of an array with constant
5700 size, set the maximum size for the allocation of temporaries. */
5707 }
5711 {
5715 tree gnu_field;
5719 {
5724 }
5728 /* For discriminant references in tagged types always substitute the
5729 corresponding discriminant as the actual selected component. */
5734 /* For discriminant references of untagged types always substitute the
5735 corresponding stored discriminant. */
5739 /* Handle extracting the real or imaginary part of a complex.
5740 The real part is the first field and the imaginary the last. */
5745 else
5746 {
5749 /* If there are discriminants, the prefix might be evaluated more
5750 than once, which is a problem if it has side-effects. */
5757 gnu_result
5761 && lvalue_required_for_attribute_p
5763 }
5767 /* If this is an atomic access on the RHS for which synchronization is
5768 required, build the atomic load. */
5772 }
5776 {
5777 /* The attribute designator. */
5780 /* The Elab_Spec and Elab_Body attributes are special in that Prefix
5781 is a unit, not an object with a GCC equivalent. */
5783 return
5791 }
5795 /* Like 'Access as far as we are concerned. */
5803 {
5804 tree gnu_aggr_type;
5806 /* ??? It is wrong to evaluate the type now, but there doesn't
5807 seem to be any other practical way of doing it. */
5811 gnu_aggr_type = gnu_result_type
5816 gnu_aggr_type
5823 NULL);
5827 gnu_result
5830 gnu_aggr_type);
5833 gnu_aggr_type,
5836 gnu_result
5837 = build_binary_op
5842 (Next
5844 else
5848 }
5856 else
5863 /* Get the operand expression. */
5867 /* If this is a qualified expression for a tagged type, we mark the type
5868 as used. Because of polymorphism, this might be the only reference to
5869 the tagged type in the program while objects have it as dynamic type.
5870 The debugger needs to see it to display these objects properly. */
5874 gnu_result
5878 kind == N_Type_Conversion
5885 /* Skip further processing if the conversion is deemed a no-op. */
5887 {
5890 }
5894 /* If the result is a pointer type, see if we are improperly
5895 converting to a stricter alignment. */
5898 {
5904 post_error_ne_tree_2
5908 }
5910 /* If we are converting a descriptor to a function pointer, first
5911 build the pointer. */
5923 {
5928 /* GNAT_RANGE is either an N_Range node or an identifier denoting a
5929 subtype. */
5931 {
5934 }
5937 {
5942 }
5943 else
5948 /* If LOW and HIGH are identical, perform an equality test. Otherwise,
5949 ensure that GNU_OBJ is evaluated only once and perform a full range
5950 test. */
5952 gnu_result
5954 else
5955 {
5964 gnu_result
5966 }
5969 gnu_result
5971 }
5979 ? RDIV_EXPR
5986 /* These can either be operations on booleans or on modular types.
5987 Fall through for boolean types since that's the way GNU_CODES is
5988 set up. */
5990 Modular_Integer_Kind))
5991 {
5992 enum tree_code code
6003 }
6005 /* ... fall through ... */
6017 {
6021 tree gnu_type;
6027 /* Pending generic support for efficient vector logical operations in
6028 GCC, convert vectors to their representative array type view and
6029 fallthrough. */
6033 /* If this is a comparison operator, convert any references to
6034 an unconstrained array value into a reference to the
6035 actual array. */
6037 {
6040 }
6042 /* If the result type is a private type, its full view may be a
6043 numeric subtype. The representation we need is that of its base
6044 type, given that it is the result of an arithmetic operation. */
6046 gnu_type = gnu_result_type
6049 /* If this is a shift whose count is not guaranteed to be correct,
6050 we need to adjust the shift count. */
6052 {
6054 tree gnu_max_shift
6061 gnu_rhs
6062 = build_binary_op
6065 gnu_count_type,
6066 gnu_max_shift,
6068 integer_one_node)),
6069 gnu_rhs);
6070 }
6072 /* For right shifts, the type says what kind of shift to do,
6073 so we may need to choose a different type. In this case,
6074 we have to ignore integer overflow lest it propagates all
6075 the way down and causes a CE to be explicitly raised. */
6077 {
6080 }
6083 {
6086 }
6089 {
6095 }
6097 /* Instead of expanding overflow checks for addition, subtraction
6098 and multiplication itself, the front end will leave this to
6099 the back end when Backend_Overflow_Checks_On_Target is set.
6100 As the GCC back end itself does not know yet how to properly
6101 do overflow checking, do it here. The goal is to push
6102 the expansions further into the back end over time. */
6111 else
6112 {
6113 /* Some operations, e.g. comparisons of arrays, generate complex
6114 trees that need to be annotated while they are being built. */
6117 }
6119 /* If this is a logical shift with the shift count not verified,
6120 we must return zero if it is too large. We cannot compensate
6121 above in this case. */
6124 gnu_result
6125 = build_cond_expr
6128 gnu_rhs,
6132 gnu_result);
6133 }
6137 {
6140 tree gnu_false
6144 gnu_result
6146 }
6155 /* This case can apply to a boolean or a modular type.
6156 Fall through for a boolean operand since GNU_CODES is set
6157 up to handle this. */
6161 {
6165 gnu_expr);
6167 }
6169 /* ... fall through ... */
6176 else
6183 gnu_result
6186 else
6192 {
6194 tree gnu_type;
6199 /* The Expression operand can either be an N_Identifier or
6200 Expanded_Name, which must represent a type, or a
6201 N_Qualified_Expression, which contains both the object type and an
6202 initial value for the object. */
6207 {
6208 Entity_Id gnat_desig_type
6216 gnu_init
6222 else
6223 {
6227 }
6229 /* See the N_Qualified_Expression case for the rationale. */
6234 }
6235 else
6242 ignore_init_type);
6243 }
6246 /**************************/
6247 /* Chapter 5: Statements */
6248 /**************************/
6256 /* When not optimizing, turn null statements from source into gotos to
6257 the next statement that the middle-end knows how to preserve. */
6259 {
6270 }
6271 else
6276 /* Get the LHS and RHS of the statement and convert any reference to an
6277 unconstrained array into a reference to the underlying array. */
6280 /* If the type has a size that overflows, convert this into raise of
6281 Storage_Error: execution shouldn't have gotten here anyway. */
6285 N_Raise_Storage_Error);
6287 gnu_result
6290 else
6291 {
6292 gnu_rhs
6295 /* If range check is needed, emit code to generate it. */
6298 gnat_node);
6302 else
6303 gnu_result
6306 /* If the type being assigned is an array type and the two sides are
6307 not completely disjoint, play safe and use memmove. But don't do
6308 it for a bit-packed array as it might not be byte-aligned. */
6313 {
6327 }
6328 }
6332 {
6335 /* Make the outer COND_EXPR. Avoid non-determinism. */
6344 /* Now make a COND_EXPR for each of the "else if" parts. Put each
6345 into the previous "else" part and point to where to put any
6346 outer "else". Also avoid non-determinism. */
6350 {
6360 }
6363 }
6375 /* The only way to enter the block is to fall through to it. */
6377 {
6384 }
6385 else
6390 gnu_result
6400 {
6403 /* If the subprogram is a function, we must return the expression. */
6405 {
6408 /* If this function has copy-in/copy-out parameters, get the real
6409 object for the return. See Subprogram_to_gnu. */
6412 else
6415 /* Get the GCC tree for the expression to be returned. */
6418 /* Do not remove the padding from GNU_RET_VAL if the inner type is
6419 self-referential since we want to allocate the fixed size. */
6421 && TYPE_IS_PADDING_P
6423 && CONTAINS_PLACEHOLDER_P
6427 /* If the function returns by direct reference, return a pointer
6428 to the return value. */
6433 /* Otherwise, if it returns an unconstrained array, we have to
6434 allocate a new version of the result and return it. */
6436 {
6439 /* And find out whether this is a candidate for Named Return
6440 Value. If so, record it. */
6442 {
6445 /* Strip useless conversions around the return value. */
6449 /* Strip unpadding around the return value. */
6451 && TYPE_IS_PADDING_P
6455 /* Now apply the test to the return value. */
6457 {
6463 }
6464 }
6467 gnu_ret_val,
6472 }
6474 /* Otherwise, if it returns by invisible reference, dereference
6475 the pointer it is passed using the type of the return value
6476 and build the copy operation manually. This ensures that we
6477 don't copy too much data, for example if the return type is
6478 unconstrained with a maximum size. */
6480 {
6481 tree gnu_ret_deref
6483 gnu_ret_obj);
6488 }
6489 }
6491 else
6494 /* If we have a return label defined, convert this into a branch to
6495 that label. The return proper will be handled elsewhere. */
6497 {
6500 gnu_ret_val));
6505 /* When not optimizing, make sure the return is preserved. */
6508 }
6510 /* Otherwise, build a regular return. */
6511 else
6513 }
6517 gnu_result
6521 /***************************/
6522 /* Chapter 6: Subprograms */
6523 /***************************/
6526 /* Unless there is a freeze node, declare the subprogram. We consider
6527 this a "definition" even though we're not generating code for
6528 the subprogram because we will be making the corresponding GCC
6529 node here. */
6538 /* This subprogram doesn't exist for code generation purposes, but we
6539 have to elaborate the types of any parameters and result, unless
6540 they are imported types (nothing to generate in this case).
6542 The parameter list may contain types with freeze nodes, e.g. not null
6543 subtypes, so the subprogram itself may carry a freeze node, in which
6544 case its elaboration must be deferred. */
6546 /* Process the parameter types first. */
6549 = First_Formal_With_Extras
6557 /* Then the result type, set to Standard_Void_Type for procedures. */
6558 {
6559 Entity_Id gnat_temp_type
6564 }
6570 /* For a child unit identifier go up a level to get the specification.
6571 We get this when we try to find the spec of a child unit package
6572 that is the compilation unit being compiled. */
6586 /************************/
6587 /* Chapter 7: Packages */
6588 /************************/
6604 /* If this is the body of a generic package - do nothing. */
6606 {
6609 }
6620 /********************************/
6621 /* Chapter 8: Visibility Rules */
6622 /********************************/
6626 /* Nothing to do here - but these may appear in list of declarations. */
6630 /*********************/
6631 /* Chapter 9: Tasks */
6632 /*********************/
6643 /*********************************************************/
6644 /* Chapter 10: Program Structure and Compilation Issues */
6645 /*********************************************************/
6648 /* This is not called for the main unit on which gigi is invoked. */
6657 /* Simply process whatever unit is being inserted. */
6660 else
6661 {
6664 }
6671 /***************************/
6672 /* Chapter 11: Exceptions */
6673 /***************************/
6676 /* If there is an At_End procedure attached to this node, and the EH
6677 mechanism is SJLJ, we must have at least a corresponding At_End
6678 handler, unless the No_Exception_Handlers restriction is set. */
6693 else
6698 /* Only for reraise in back-end exceptions mode. */
6705 /* Clear the current exception pointer so that the occurrence won't be
6706 deallocated. */
6745 /******************************/
6746 /* Chapter 12: Generic Units */
6747 /******************************/
6757 /* These nodes can appear on a declaration list but there is nothing to
6758 to be done with them. */
6762 /**************************************************/
6763 /* Chapter 13: Representation Clauses and */
6764 /* Implementation-Dependent Features */
6765 /**************************************************/
6770 /* The only one we need to deal with is 'Address since, for the others,
6771 the front-end puts the information elsewhere. */
6775 /* And we only deal with 'Address if the object has a Freeze node. */
6780 /* Get the value to use as the address and save it as the equivalent
6781 for the object. When it is frozen, gnat_to_gnu_entity will do the
6782 right thing. */
6789 /* We do nothing with these. SEM puts the information elsewhere. */
6795 {
6805 /* First retrieve the 3 operand lists built by the front-end. */
6808 {
6815 }
6819 {
6826 }
6830 gnu_clobbers
6833 gnu_clobbers);
6835 /* Then perform some standard checking and processing on the
6836 operands. In particular, mark them addressable if needed. */
6844 {
6846 constraint
6852 {
6853 /* If the operand is going to end up in memory,
6854 mark it addressable. Note that we don't test
6855 allows_mem like in the input case below; this
6856 is modelled on the C front-end. */
6858 {
6865 }
6866 }
6867 else
6871 }
6874 {
6876 constraint
6882 {
6883 /* If the operand is going to end up in memory,
6884 mark it addressable. */
6886 {
6893 }
6894 }
6895 else
6899 }
6905 }
6906 else
6911 /****************/
6912 /* Added Nodes */
6913 /****************/
6916 /* This construct doesn't define a scope so we don't wrap the statement
6917 list in a BIND_EXPR; however, we wrap it in a SAVE_EXPR to protect it
6918 from unsharing. */
6923 gnu_result
6944 {
6949 /* If this is a thin pointer, we must first dereference it to create
6950 a fat pointer, then go back below to a thin pointer. The reason
6951 for this is that we need to have a fat pointer someplace in order
6952 to properly compute the size. */
6956 gnu_ptr));
6958 /* If this is a fat pointer, the object must have been allocated with
6959 the template in front of the array. So pass the template address,
6960 and get the total size; do it by converting to a thin pointer. */
6962 gnu_ptr
6964 (TYPE_OBJECT_RECORD_TYPE
6966 gnu_ptr);
6970 /* If this is a thin pointer, the object must have been allocated with
6971 the template in front of the array. So pass the template address,
6972 and get the total size. */
6974 gnu_ptr
6976 gnu_ptr,
6978 byte_position
6979 (DECL_CHAIN
6982 /* If we have a special dynamic constrained subtype on the node, use
6983 it to compute the size; otherwise, use the designated subtype. */
6985 {
6986 gnu_actual_obj_type
6990 gnu_actual_obj_type
6992 gnu_actual_obj_type,
6995 }
6996 else
6999 gnu_result
7002 gnu_obj_type,
7005 gnat_node);
7006 }
7014 else
7019 /* The only validation we currently do on an unchecked conversion is
7020 that of aliasing assumptions. */
7032 /* These nodes should only be present when annotating types. */
7038 /* Other nodes are not supposed to reach here. */
7040 }
7042 /* If we pushed the processing of the elaboration routine, pop it back. */
7046 /* When not optimizing, turn boolean rvalues B into B != false tests
7047 so that the code just below can put the location information of the
7048 reference to B on the inequality operator for better debug info. */
7062 boolean_false_node));
7064 /* Set the location information on the result. Note that we may have
7065 no result if we tried to build a CALL_EXPR node to a procedure with
7066 no side-effects and optimization is enabled. */
7070 /* If we're supposed to return something of void_type, it means we have
7071 something we're elaborating for effect, so just return. */
7075 /* If the result is a constant that overflowed, raise Constraint_Error. */
7077 {
7079 gnu_result
7082 N_Raise_Constraint_Error));
7083 }
7085 /* If the result has side-effects and is of an unconstrained type, make a
7086 SAVE_EXPR so that we can be sure it will only be referenced once. But
7087 this is useless for a call to a function that returns an unconstrained
7088 type with default discriminant, as we cannot compute the size of the
7089 actual returned object. We must do this before any conversions. */
7097 /* Now convert the result to the result type, unless we are in one of the
7098 following cases:
7100 1. If this is the LHS of an assignment or an actual parameter of a
7101 call, return the result almost unmodified since the RHS will have
7102 to be converted to our type in that case, unless the result type
7103 has a simpler size. Likewise if there is just a no-op unchecked
7104 conversion in-between. Similarly, don't convert integral types
7105 that are the operands of an unchecked conversion since we need
7106 to ignore those conversions (for 'Valid).
7108 2. If we have a label (which doesn't have any well-defined type), a
7109 field or an error, return the result almost unmodified. Similarly,
7110 if the two types are record types with the same name, don't convert.
7111 This will be the case when we are converting from a packable version
7112 of a type to its original type and we need those conversions to be
7113 NOPs in order for assignments into these types to work properly.
7115 3. If the type is void or if we have no result, return error_mark_node
7116 to show we have no result.
7118 4. If this a call to a function that returns an unconstrained type with
7119 default discriminant, return the call expression unmodified since we
7120 cannot compute the size of the actual returned object.
7122 5. Finally, if the type of the result is already correct. */
7140 && (CONTAINS_PLACEHOLDER_P
7144 {
7145 /* Remove padding only if the inner object is of self-referential
7146 size: in that case it must be an object of unconstrained type
7147 with a default discriminant and we want to avoid copying too
7148 much data. */
7153 gnu_result);
7154 }
7163 {
7164 /* Remove any padding. */
7167 gnu_result);
7168 }
7176 == gnu_result_type
7178 ;
7183 /* We don't need any NOP_EXPR or NON_LVALUE_EXPR on the result. */
7190 }
7191 \f
7192 /* Subroutine of above to push the exception label stack. GNU_STACK is
7193 a pointer to the stack to update and GNAT_LABEL, if present, is the
7194 label to push onto the stack. */
7196 static void
7198 {
7204 }
7205 \f
7206 /* Record the current code position in GNAT_NODE. */
7208 static void
7210 {
7215 }
7217 /* Insert the code for GNAT_NODE at the position saved for that node. */
7219 static void
7221 {
7224 }
7225 \f
7226 /* Start a new statement group chained to the previous group. */
7228 void
7230 {
7233 /* First see if we can get one from the free list. */
7236 else
7242 }
7244 /* Add GNU_STMT to the current statement group. If it is an expression with
7245 no effects, it is ignored. */
7247 void
7249 {
7251 }
7253 /* Similar, but the statement is always added, regardless of side-effects. */
7255 void
7257 {
7259 }
7261 /* Like add_stmt, but set the location of GNU_STMT to that of GNAT_NODE. */
7263 void
7265 {
7269 }
7271 /* Similar, but the statement is always added, regardless of side-effects. */
7273 void
7275 {
7279 }
7281 /* Add a declaration statement for GNU_DECL to the current statement group.
7282 Get SLOC from Entity_Id. */
7284 void
7286 {
7290 /* If this is a variable that Gigi is to ignore, we may have been given
7291 an ERROR_MARK. So test for it. We also might have been given a
7292 reference for a renaming. So only do something for a decl. Also
7293 ignore a TYPE_DECL for an UNCONSTRAINED_ARRAY_TYPE. */
7301 /* If we are external or global, we don't want to output the DECL_EXPR for
7302 this DECL node since we already have evaluated the expressions in the
7303 sizes and positions as globals and doing it again would be wrong. */
7305 {
7306 /* Mark everything as used to prevent node sharing with subprograms.
7307 Note that walk_tree knows how to deal with TYPE_DECL, but neither
7308 VAR_DECL nor CONST_DECL. This appears to be somewhat arbitrary. */
7312 {
7316 }
7317 /* In any case, we have to deal with our own TYPE_ADA_SIZE field. */
7322 }
7323 else
7326 /* If this is a variable and an initializer is attached to it, it must be
7327 valid for the context. Similar to init_const in create_var_decl_1. */
7334 {
7335 /* If GNU_DECL has a padded type, convert it to the unpadded
7336 type so the assignment is done properly. */
7339 else
7346 {
7349 }
7352 }
7353 }
7355 /* Callback for walk_tree to mark the visited trees rooted at *TP. */
7357 static tree
7359 {
7365 /* Don't mark a dummy type as visited because we want to mark its sizes
7366 and fields once it's filled in. */
7374 }
7376 /* Mark nodes rooted at T with TREE_VISITED and types as having their
7377 sized gimplified. We use this to indicate all variable sizes and
7378 positions in global types may not be shared by any subprogram. */
7380 void
7382 {
7384 }
7386 /* Add GNU_CLEANUP, a cleanup action, to the current code group and
7387 set its location to that of GNAT_NODE if present. */
7389 static void
7391 {
7395 }
7397 /* Set the BLOCK node corresponding to the current code group to GNU_BLOCK. */
7399 void
7401 {
7404 }
7406 /* Return code corresponding to the current code group. It is normally
7407 a STATEMENT_LIST, but may also be a BIND_EXPR or TRY_FINALLY_EXPR if
7408 BLOCK or cleanups were set. */
7410 tree
7412 {
7416 /* If this is a null list, allocate a new STATEMENT_LIST. Then, if there
7417 are cleanups, make a TRY_FINALLY_EXPR. Last, if there is a BLOCK,
7418 make a BIND_EXPR. Note that we nest in that because the cleanup may
7419 reference variables in the block. */
7431 /* Remove this group from the stack and add it to the free list. */
7437 }
7439 /* Return whether the current statement group may fall through. */
7443 {
7446 else
7448 }
7450 /* Add a list of statements from GNAT_LIST, a possibly-empty list of
7451 statements.*/
7453 static void
7455 {
7456 Node_Id gnat_node;
7462 }
7464 /* Build a tree from GNAT_LIST, a possibly-empty list of statements.
7465 If BINDING_P is true, push and pop a binding level around the list. */
7467 static tree
7469 {
7479 }
7480 \f
7481 /* Generate GIMPLE in place for the expression at *EXPR_P. */
7483 int
7486 {
7488 tree op;
7494 {
7496 /* If this is for a scalar, just make a VAR_DECL for it. If for
7497 an aggregate, get a null pointer of the appropriate type and
7498 dereference it. */
7502 integer_zero_node));
7503 else
7504 {
7507 }
7513 /* We should only do this if we are just elaborating for side-effects,
7514 but we can't know that yet. */
7521 /* If we are taking the address of a constant CONSTRUCTOR, make sure it
7522 is put into static memory. We know that it's going to be read-only
7523 given the semantics we have and it must be in static memory when the
7524 reference is in an elaboration procedure. */
7526 {
7530 }
7537 /* If we are view-converting a CONSTRUCTOR or a call from an aggregate
7538 type to a scalar one, explicitly create the local temporary. That's
7539 required if the type is passed by reference. */
7543 {
7552 }
7559 /* The expressions for the RM bounds must be gimplified to ensure that
7560 they are properly elaborated. See gimplify_decl_expr. */
7564 {
7569 {
7574 {
7578 }
7582 {
7586 }
7588 }
7593 }
7595 /* ... fall through ... */
7599 }
7600 }
7602 /* Generate GIMPLE in place for the statement at *STMT_P. */
7604 static enum gimplify_status
7606 {
7610 {
7616 {
7621 tree t;
7623 /* Build the condition expression from the test, if any. */
7625 gnu_cond
7629 /* Set to emit the statements of the loop. */
7632 /* We first emit the start label and then a conditional jump to the
7633 end label if there's a top condition, then the update if it's at
7634 the top, then the body of the loop, then a conditional jump to
7635 the end label if there's a bottom condition, then the update if
7636 it's at the bottom, and finally a jump to the start label and the
7637 definition of the end label. */
7639 gnu_start_label),
7640 stmt_p);
7661 gnu_end_label),
7662 stmt_p);
7664 }
7667 /* Build a statement to jump to the corresponding end label, then
7668 see if it needs to be conditional. */
7677 }
7678 }
7679 \f
7680 /* Force references to each of the entities in packages withed by GNAT_NODE.
7681 Operate recursively but check that we aren't elaborating something more
7682 than once.
7684 This routine is exclusively called in type_annotate mode, to compute DDA
7685 information for types in withed units, for ASIS use. */
7687 static void
7689 {
7692 /* Process each unit only once. As we trace the context of all relevant
7693 units transitively, including generic bodies, we may encounter the
7694 same generic unit repeatedly. */
7698 /* Save entities in all context units. A body may have an implicit_with
7699 on its own spec, if the context includes a child unit, so don't save
7700 the spec twice. */
7707 {
7711 {
7728 }
7730 {
7731 Node_Id gnat_body
7734 /* Retrieve compilation unit node of generic body. */
7739 /* If body is available, elaborate its context. */
7742 }
7743 }
7747 }
7748 \f
7749 /* Do the processing of GNAT_NODE, an N_Freeze_Entity. */
7751 static void
7753 {
7758 /* If this is a package, we need to generate code for the package. */
7760 {
7761 insert_code_for
7765 }
7767 /* Don't do anything for class-wide types as they are always transformed
7768 into their root type. */
7772 /* Check for an old definition. This freeze node might be for an Itype. */
7773 gnu_old
7776 /* If this entity has an address representation clause, GNU_OLD is the
7777 address, so discard it here. */
7781 /* Don't do anything for subprograms that may have been elaborated before
7782 their freeze nodes. This can happen, for example, because of an inner
7783 call in an instance body or because of previous compilation of a spec
7784 for inlining purposes. */
7792 /* If we have a non-dummy type old tree, we have nothing to do, except
7793 aborting if this is the public view of a private type whose full view was
7794 not delayed, as this node was never delayed as it should have been. We
7795 let this happen for concurrent types and their Corresponding_Record_Type,
7796 however, because each might legitimately be elaborated before its own
7797 freeze node, e.g. while processing the other. */
7801 {
7809 }
7811 /* Reset the saved tree, if any, and elaborate the object or type for real.
7812 If there is a full view, elaborate it and use the result. And, if this
7813 is the root type of a class-wide type, reuse it for the latter. */
7815 {
7825 }
7829 {
7832 /* Propagate back-annotations from full view to partial view. */
7842 /* The above call may have defined this entity (the simplest example
7843 of this is when we have a private enumeral type since the bounds
7844 will have the public view). */
7847 }
7848 else
7849 {
7850 tree gnu_init
7856 }
7863 /* If we have an old type and we've made pointers to this type, update those
7864 pointers. If this is a Taft amendment type in the main unit, we need to
7865 mark the type as used since other units referencing it don't see the full
7866 declaration and, therefore, cannot mark it as used themselves. */
7868 {
7873 }
7874 }
7875 \f
7876 /* Elaborate decls in the lists GNAT_DECLS and GNAT_DECLS2, if present.
7877 We make two passes, one to elaborate anything other than bodies (but
7878 we declare a function if there was no spec). The second pass
7879 elaborates the bodies.
7881 GNAT_END_LIST gives the element in the list past the end. Normally,
7882 this is Empty, but can be First_Real_Statement for a
7883 Handled_Sequence_Of_Statements.
7885 We make a complete pass through both lists if PASS1P is true, then make
7886 the second pass over both lists if PASS2P is true. The lists usually
7887 correspond to the public and private parts of a package. */
7889 static void
7892 {
7894 Node_Id gnat_decl;
7904 {
7905 /* For package specs, we recurse inside the declarations,
7906 thus taking the two pass approach inside the boundary. */
7914 /* Similarly for any declarations in the actions of a
7915 freeze node. */
7917 {
7920 }
7922 /* Package bodies with freeze nodes get their elaboration deferred
7923 until the freeze node, but the code must be placed in the right
7924 place, so record the code position now. */
7932 (Corresponding_Spec
7935 record_code_position
7938 /* We defer most subprogram bodies to the second pass. */
7940 {
7942 {
7948 }
7949 }
7951 /* For bodies and stubs that act as their own specs, the entity
7952 itself must be elaborated in the first pass, because it may
7953 be used in other declarations. */
7955 {
7956 Node_Id gnat_subprog_id
7963 }
7965 /* Concurrent stubs stand for the corresponding subprogram bodies,
7966 which are deferred like other bodies. */
7969 ;
7971 else
7973 }
7975 /* Here we elaborate everything we deferred above except for package bodies,
7976 which are elaborated at their freeze nodes. Note that we must also
7977 go inside things (package specs and freeze nodes) the first pass did. */
7983 {
7999 }
8000 }
8001 \f
8002 /* Make a unary operation of kind CODE using build_unary_op, but guard
8003 the operation by an overflow check. CODE can be one of NEGATE_EXPR
8004 or ABS_EXPR. GNU_TYPE is the type desired for the result. Usually
8005 the operation is to be performed in that type. GNAT_NODE is the gnat
8006 node conveying the source location for which the error should be
8007 signaled. */
8009 static tree
8011 Node_Id gnat_node)
8012 {
8021 }
8023 /* Make a binary operation of kind CODE using build_binary_op, but guard
8024 the operation by an overflow check. CODE can be one of PLUS_EXPR,
8025 MINUS_EXPR or MULT_EXPR. GNU_TYPE is the type desired for the result.
8026 Usually the operation is to be performed in that type. GNAT_NODE is
8027 the GNAT node conveying the source location for which the error should
8028 be signaled. */
8030 static tree
8033 {
8038 tree gnu_expr;
8041 tree rhs_lt_zero;
8042 tree check_pos;
8043 tree check_neg;
8044 tree check;
8049 /* Prefer a constant or known-positive rhs to simplify checks. */
8054 {
8058 }
8061 ? boolean_false_node
8064 /* ??? Should use more efficient check for operand_equal_p (lhs, rhs, 0) */
8066 /* Try a few strategies that may be cheaper than the general
8067 code at the end of the function, if the rhs is not known.
8068 The strategies are:
8069 - Call library function for 64-bit multiplication (complex)
8070 - Widen, if input arguments are sufficiently small
8071 - Determine overflow using wrapped result for addition/subtraction. */
8074 {
8075 /* Even for add/subtract double size to get another base type. */
8079 {
8085 }
8090 {
8097 tree check = build_binary_op
8106 return
8108 }
8111 {
8113 tree wrapped_expr = convert
8118 tree result = convert
8121 /* Overflow when (rhs < 0) ^ (wrapped_expr < lhs)), for addition
8122 or when (rhs < 0) ^ (wrapped_expr > lhs) for subtraction. */
8123 tree check = build_binary_op
8128 return
8130 }
8131 }
8134 {
8136 /* When rhs >= 0, overflow when lhs > type_max - rhs. */
8141 /* When rhs < 0, overflow when lhs < type_min - rhs. */
8148 /* When rhs >= 0, overflow when lhs < type_min + rhs. */
8153 /* When rhs < 0, overflow when lhs > type_max + rhs. */
8160 /* The check here is designed to be efficient if the rhs is constant,
8161 but it will work for any rhs by using integer division.
8162 Four different check expressions determine whether X * C overflows,
8163 depending on C.
8164 C == 0 => false
8165 C > 0 => X > type_max / C || X < type_min / C
8166 C == -1 => X == type_min
8167 C < -1 => X > type_min / C || X < type_max / C */
8172 check_pos
8175 rhs),
8178 boolean_type_node,
8181 boolean_type_node,
8184 check_neg
8189 type_min),
8192 boolean_type_node,
8195 boolean_type_node,
8201 }
8205 /* If we can fold the expression to a constant, just return it.
8206 The caller will deal with overflow, no need to generate a check. */
8211 check_pos);
8214 }
8216 /* Emit code for a range check. GNU_EXPR is the expression to be checked,
8217 GNAT_RANGE_TYPE the gnat type or subtype containing the bounds against
8218 which we have to check. GNAT_NODE is the GNAT node conveying the source
8219 location for which the error should be signaled. */
8221 static tree
8223 {
8227 /* If GNU_EXPR has GNAT_RANGE_TYPE as its base type, no check is needed.
8228 This can for example happen when translating 'Val or 'Value. */
8232 /* Range checks can only be applied to types with ranges. */
8236 /* If GNU_EXPR has an integral type that is narrower than GNU_RANGE_TYPE,
8237 we can't do anything since we might be truncating the bounds. No
8238 check is needed in this case. */
8244 /* Checked expressions must be evaluated only once. */
8247 /* Note that the form of the check is
8248 (not (expr >= lo)) or (not (expr <= hi))
8249 the reason for this slightly convoluted form is that NaNs
8250 are not considered to be in range in the float case. */
8251 return emit_check
8253 invert_truthvalue
8257 TYPE_MIN_VALUE
8259 invert_truthvalue
8263 TYPE_MAX_VALUE
8266 }
8267 \f
8268 /* Emit code for an index check. GNU_ARRAY_OBJECT is the array object which
8269 we are about to index, GNU_EXPR is the index expression to be checked,
8270 GNU_LOW and GNU_HIGH are the lower and upper bounds against which GNU_EXPR
8271 has to be checked. Note that for index checking we cannot simply use the
8272 emit_range_check function (although very similar code needs to be generated
8273 in both cases) since for index checking the array type against which we are
8274 checking the indices may be unconstrained and consequently we need to get
8275 the actual index bounds from the array object itself (GNU_ARRAY_OBJECT).
8276 The place where we need to do that is in subprograms having unconstrained
8277 array formal parameters. GNAT_NODE is the GNAT node conveying the source
8278 location for which the error should be signaled. */
8280 static tree
8283 {
8284 tree gnu_expr_check;
8286 /* Checked expressions must be evaluated only once. */
8289 /* Must do this computation in the base type in case the expression's
8290 type is an unsigned subtypes. */
8293 /* If GNU_LOW or GNU_HIGH are a PLACEHOLDER_EXPR, qualify them by
8294 the object we are handling. */
8298 return emit_check
8301 gnu_expr_check,
8303 gnu_low)),
8305 gnu_expr_check,
8307 gnu_high))),
8309 }
8310 \f
8311 /* GNU_COND contains the condition corresponding to an access, discriminant or
8312 range check of value GNU_EXPR. Build a COND_EXPR that returns GNU_EXPR if
8313 GNU_COND is false and raises a CONSTRAINT_ERROR if GNU_COND is true.
8314 REASON is the code that says why the exception was raised. GNAT_NODE is
8315 the GNAT node conveying the source location for which the error should be
8316 signaled. */
8318 static tree
8320 {
8321 tree gnu_call
8323 tree gnu_result
8327 gnu_expr);
8329 /* GNU_RESULT has side effects if and only if GNU_EXPR has:
8330 we don't need to evaluate it just for the check. */
8334 }
8335 \f
8336 /* Return an expression that converts GNU_EXPR to GNAT_TYPE, doing overflow
8337 checks if OVERFLOW_P is true and range checks if RANGE_P is true.
8338 GNAT_TYPE is known to be an integral type. If TRUNCATE_P true, do a
8339 float to integer conversion with truncation; otherwise round.
8340 GNAT_NODE is the GNAT node conveying the source location for which the
8341 error should be signaled. */
8343 static tree
8346 {
8353 /* If we are not doing any checks, the output is an integral type, and
8354 the input is not a floating type, just do the conversion. This
8355 shortcut is required to avoid problems with packed array types
8356 and simplifies code in all cases anyway. */
8361 /* First convert the expression to its base type. This
8362 will never generate code, but makes the tests below much simpler.
8363 But don't do this if converting from an integer type to an unconstrained
8364 array type since then we need to get the bounds from the original
8365 (unpacked) type. */
8369 /* If overflow checks are requested, we need to be sure the result will
8370 fit in the output base type. But don't do this if the input
8371 is integer and the output floating-point. */
8374 {
8375 /* Ensure GNU_EXPR only gets evaluated once. */
8383 /* Convert the lower bounds to signed types, so we're sure we're
8384 comparing them properly. Likewise, convert the upper bounds
8385 to unsigned types. */
8399 /* Check each bound separately and only if the result bound
8400 is tighter than the bound on the input type. Note that all the
8401 types are base types, so the bounds must be constant. Also,
8402 the comparison is done in the base type of the input, which
8403 always has the proper signedness. First check for input
8404 integer (which means output integer), output float (which means
8405 both float), or mixed, in which case we always compare.
8406 Note that we have to do the comparison which would *fail* in the
8407 case of an error since if it's an FP comparison and one of the
8408 values is a NaN or Inf, the comparison will fail. */
8415 gnu_cond
8416 = invert_truthvalue
8419 gnu_out_lb)));
8427 gnu_cond
8429 invert_truthvalue
8431 gnu_input,
8433 gnu_out_ub))));
8438 }
8440 /* Now convert to the result base type. If this is a non-truncating
8441 float-to-integer conversion, round. */
8444 {
8450 /* The following calculations depend on proper rounding to even
8451 of each arithmetic operation. In order to prevent excess
8452 precision from spoiling this property, use the widest hardware
8453 floating-point type if FP_ARITH_MAY_WIDEN is true. */
8454 calc_type
8457 /* FIXME: Should not have padding in the first place. */
8461 /* Compute the exact value calc_type'Pred (0.5) at compile time. */
8465 half_minus_pred_half);
8468 /* If the input is strictly negative, subtract this value
8469 and otherwise add it from the input. For 0.5, the result
8470 is exactly between 1.0 and the machine number preceding 1.0
8471 (for calc_type). Since the last bit of 1.0 is even, this 0.5
8472 will round to 1.0, while all other number with an absolute
8473 value less than 0.5 round to 0.0. For larger numbers exactly
8474 halfway between integers, rounding will always be correct as
8475 the true mathematical result will be closer to the higher
8476 integer compared to the lower one. So, this constant works
8477 for all floating-point numbers.
8479 The reason to use the same constant with subtract/add instead
8480 of a positive and negative constant is to allow the comparison
8481 to be scheduled in parallel with retrieval of the constant and
8482 conversion of the input to the calc_type (if necessary). */
8487 gnu_comp
8489 gnu_add_pred_half
8491 gnu_subtract_pred_half
8495 }
8501 else
8504 /* Finally, do the range check if requested. Note that if the result type
8505 is a modular type, the range check is actually an overflow check. */
8512 }
8513 \f
8514 /* Return true if GNU_EXPR can be directly addressed. This is the case
8515 unless it is an expression involving computation or if it involves a
8516 reference to a bitfield or to an object not sufficiently aligned for
8517 its type. If GNU_TYPE is non-null, return true only if GNU_EXPR can
8518 be directly addressed as an object of this type.
8520 *** Notes on addressability issues in the Ada compiler ***
8522 This predicate is necessary in order to bridge the gap between Gigi
8523 and the middle-end about addressability of GENERIC trees. A tree
8524 is said to be addressable if it can be directly addressed, i.e. if
8525 its address can be taken, is a multiple of the type's alignment on
8526 strict-alignment architectures and returns the first storage unit
8527 assigned to the object represented by the tree.
8529 In the C family of languages, everything is in practice addressable
8530 at the language level, except for bit-fields. This means that these
8531 compilers will take the address of any tree that doesn't represent
8532 a bit-field reference and expect the result to be the first storage
8533 unit assigned to the object. Even in cases where this will result
8534 in unaligned accesses at run time, nothing is supposed to be done
8535 and the program is considered as erroneous instead (see PR c/18287).
8537 The implicit assumptions made in the middle-end are in keeping with
8538 the C viewpoint described above:
8539 - the address of a bit-field reference is supposed to be never
8540 taken; the compiler (generally) will stop on such a construct,
8541 - any other tree is addressable if it is formally addressable,
8542 i.e. if it is formally allowed to be the operand of ADDR_EXPR.
8544 In Ada, the viewpoint is the opposite one: nothing is addressable
8545 at the language level unless explicitly declared so. This means
8546 that the compiler will both make sure that the trees representing
8547 references to addressable ("aliased" in Ada parlance) objects are
8548 addressable and make no real attempts at ensuring that the trees
8549 representing references to non-addressable objects are addressable.
8551 In the first case, Ada is effectively equivalent to C and handing
8552 down the direct result of applying ADDR_EXPR to these trees to the
8553 middle-end works flawlessly. In the second case, Ada cannot afford
8554 to consider the program as erroneous if the address of trees that
8555 are not addressable is requested for technical reasons, unlike C;
8556 as a consequence, the Ada compiler must arrange for either making
8557 sure that this address is not requested in the middle-end or for
8558 compensating by inserting temporaries if it is requested in Gigi.
8560 The first goal can be achieved because the middle-end should not
8561 request the address of non-addressable trees on its own; the only
8562 exception is for the invocation of low-level block operations like
8563 memcpy, for which the addressability requirements are lower since
8564 the type's alignment can be disregarded. In practice, this means
8565 that Gigi must make sure that such operations cannot be applied to
8566 non-BLKmode bit-fields.
8568 The second goal is achieved by means of the addressable_p predicate,
8569 which computes whether a temporary must be inserted by Gigi when the
8570 address of a tree is requested; if so, the address of the temporary
8571 will be used in lieu of that of the original tree and some glue code
8572 generated to connect everything together. */
8574 static bool
8576 {
8577 /* For an integral type, the size of the actual type of the object may not
8578 be greater than that of the expected type, otherwise an indirect access
8579 in the latter type wouldn't correctly set all the bits of the object. */
8585 /* The size of the actual type of the object may not be smaller than that
8586 of the expected type, otherwise an indirect access in the latter type
8587 would be larger than the object. But only record types need to be
8588 considered in practice for this case. */
8595 {
8600 /* All DECLs are addressable: if they are in a register, we can force
8601 them to memory. */
8606 /* Taking the address of a dereference yields the original pointer. */
8611 /* Taking the address yields a pointer to the constant pool. */
8615 /* Taking the address of a static constructor yields a pointer to the
8616 tree constant pool. */
8628 /* All rvalues are deemed addressable since taking their address will
8629 force a temporary to be created by the middle-end. */
8633 /* The address of a compound expression is that of its 2nd operand. */
8637 /* We accept &COND_EXPR as soon as both operands are addressable and
8638 expect the outcome to be the address of the selected operand. */
8644 /* Even with DECL_BIT_FIELD cleared, we have to ensure that
8645 the field is sufficiently aligned, in case it is subject
8646 to a pragma Component_Alignment. But we don't need to
8647 check the alignment of the containing record, as it is
8648 guaranteed to be not smaller than that of its most
8649 aligned field that is not a bit-field. */
8650 && (!STRICT_ALIGNMENT
8653 /* The field of a padding record is always addressable. */
8667 {
8668 /* This is addressable if we can avoid a copy. */
8672 && (!STRICT_ALIGNMENT
8677 && (!STRICT_ALIGNMENT
8683 }
8687 }
8688 }
8689 \f
8690 /* Do the processing for the declaration of a GNAT_ENTITY, a type. If
8691 a separate Freeze node exists, delay the bulk of the processing. Otherwise
8692 make a GCC type for GNAT_ENTITY and set up the correspondence. */
8694 void
8696 {
8697 tree gnu_old
8699 tree gnu_new;
8701 /* If we are to delay elaboration of this type, just do any
8702 elaborations needed for expressions within the declaration and
8703 make a dummy type entry for this node and its Full_View (if
8704 any) in case something points to it. Don't do this if it
8705 has already been done (the only way that can happen is if
8706 the private completion is also delayed). */
8712 {
8716 {
8721 {
8725 }
8726 }
8729 }
8731 /* If we saved away a dummy type for this node it means that this
8732 made the type that corresponds to the full type of an incomplete
8733 type. Clear that type for now and then update the type in the
8734 pointers. */
8736 {
8741 }
8743 /* Now fully elaborate the type. */
8747 /* If we have an old type and we've made pointers to this type, update those
8748 pointers. If this is a Taft amendment type in the main unit, we need to
8749 mark the type as used since other units referencing it don't see the full
8750 declaration and, therefore, cannot mark it as used themselves. */
8752 {
8757 }
8759 /* If this is a record type corresponding to a task or protected type
8760 that is a completion of an incomplete type, perform a similar update
8761 on the type. ??? Including protected types here is a guess. */
8765 {
8766 tree gnu_task_old
8776 }
8777 }
8778 \f
8779 /* GNAT_ENTITY is the type of the resulting constructor, GNAT_ASSOC is the
8780 front of the Component_Associations of an N_Aggregate and GNU_TYPE is the
8781 GCC type of the corresponding record type. Return the CONSTRUCTOR. */
8783 static tree
8785 {
8788 /* We test for GNU_FIELD being empty in the case where a variant
8789 was the last thing since we don't take things off GNAT_ASSOC in
8790 that case. We check GNAT_ASSOC in case we have a variant, but it
8791 has no fields. */
8794 {
8799 /* The expander is supposed to put a single component selector name
8800 in every record component association. */
8803 /* Ignore fields that have Corresponding_Discriminants since we'll
8804 be setting that field in the parent. */
8809 /* Also ignore discriminants of Unchecked_Unions. */
8814 /* Before assigning a value in an aggregate make sure range checks
8815 are done if required. Then convert to the type of the field. */
8821 /* Add the field and expression to the list. */
8823 }
8827 #ifdef ENABLE_CHECKING
8828 /* Verify that every entry in GNU_LIST was used. */
8831 #endif
8834 }
8836 /* Build a possibly nested constructor for array aggregates. GNAT_EXPR is
8837 the first element of an array aggregate. It may itself be an aggregate.
8838 GNU_ARRAY_TYPE is the GCC type corresponding to the array aggregate.
8839 GNAT_COMPONENT_TYPE is the type of the array component; it is needed
8840 for range checking. */
8842 static tree
8844 Entity_Id gnat_component_type)
8845 {
8847 tree gnu_expr;
8851 {
8852 /* If the expression is itself an array aggregate then first build the
8853 innermost constructor if it is part of our array (multi-dimensional
8854 case). */
8860 gnat_component_type);
8861 else
8862 {
8865 /* Before assigning the element to the array, make sure it is
8866 in range. */
8869 }
8875 }
8878 }
8879 \f
8880 /* Subroutine of assoc_to_constructor: VALUES is a list of field associations,
8881 some of which are from RECORD_TYPE. Return a CONSTRUCTOR consisting
8882 of the associations that are from RECORD_TYPE. If we see an internal
8883 record, make a recursive call to fill it in as well. */
8885 static tree
8887 {
8892 {
8895 /* _Parent is an internal field, but may have values in the aggregate,
8896 so check for values first. */
8898 {
8901 }
8904 {
8909 }
8910 else
8911 /* If we have a record subtype, the names will match, but not the
8912 actual FIELD_DECLs. */
8915 {
8918 }
8924 }
8927 }
8928 \f
8929 /* Process a N_Validate_Unchecked_Conversion node. */
8931 static void
8933 {
8937 /* If the target is a pointer type, see if we are either converting from a
8938 non-pointer or from a pointer to a type with a different alias set and
8939 warn if so, unless the pointer has been marked to alias everything. */
8942 {
8952 target_alias_set)))
8953 {
8957 gnat_node);
8960 }
8961 }
8963 /* Likewise if the target is a fat pointer type, but we have no mechanism to
8964 mitigate the problem in this case, so we unconditionally warn. */
8966 {
8967 tree gnu_source_desig_type
8971 tree gnu_target_desig_type
8978 target_alias_set)))
8979 {
8983 gnat_node);
8984 }
8985 }
8986 }
8987 \f
8988 /* EXP is to be treated as an array or record. Handle the cases when it is
8989 an access object and perform the required dereferences. */
8991 static tree
8993 {
8994 /* If the type is a pointer, dereference it. */
8999 /* If we got a padded type, remove it too. */
9004 }
9005 \f
9006 /* Convert SLOC into LOCUS. Return true if SLOC corresponds to a source code
9007 location and false if it doesn't. In the former case, set the Gigi global
9008 variable REF_FILENAME to the simple debug file name as given by sinput. */
9010 bool
9012 {
9017 {
9020 }
9021 else
9022 {
9028 /* We can have zero if pragma Source_Reference is in effect. */
9032 /* Translate the location. */
9034 }
9036 ref_filename
9037 = IDENTIFIER_POINTER
9038 (get_identifier
9042 }
9044 /* Similar to set_expr_location, but start with the Sloc of GNAT_NODE and
9045 don't do anything if it doesn't correspond to a source location. */
9047 static void
9049 {
9050 location_t locus;
9056 }
9058 /* More elaborate version of set_expr_location_from_node to be used in more
9059 general contexts, for example the result of the translation of a generic
9060 GNAT node. */
9062 static void
9064 {
9065 /* Set the location information on the node if it is a real expression.
9066 References can be reused for multiple GNAT nodes and they would get
9067 the location information of their last use. Also make sure not to
9068 overwrite an existing location as it is probably more precise. */
9071 {
9072 CASE_CONVERT:
9080 /* ... fall through ... */
9084 {
9087 }
9089 }
9090 }
9091 \f
9092 /* Return a colon-separated list of encodings contained in encoded Ada
9093 name. */
9097 {
9101 }
9103 /* Extract the Ada name from an encoded name. */
9107 {
9111 }
9112 \f
9113 /* Post an error message. MSG is the error message, properly annotated.
9114 NODE is the node at which to post the error and the node to use for the
9115 '&' substitution. */
9117 void
9119 {
9120 String_Template temp;
9121 Fat_Pointer fp;
9127 }
9129 /* Similar to post_error, but NODE is the node at which to post the error and
9130 ENT is the node to use for the '&' substitution. */
9132 void
9134 {
9135 String_Template temp;
9136 Fat_Pointer fp;
9142 }
9144 /* Similar to post_error_ne, but NUM is the number to use for the '^'. */
9146 void
9148 {
9151 }
9153 /* Set the end_locus information for GNU_NODE, if any, from an explicit end
9154 location associated with GNAT_NODE or GNAT_NODE itself, whichever makes
9155 most sense. Return true if a sensible assignment was performed. */
9157 static bool
9159 {
9161 location_t end_locus;
9163 /* Pick the GNAT node of which we'll take the sloc to assign to the GCC node
9164 end_locus when there is one. We consider only GNAT nodes with a possible
9165 End_Label attached. If the End_Label actually was unassigned, fallback
9166 on the original node. We'd better assign an explicit sloc associated with
9167 the outer construct in any case. */
9170 {
9183 }
9187 /* Some expanded subprograms have neither an End_Label nor a Sloc
9188 attached. Notify that to callers. */
9194 {
9205 }
9206 }
9207 \f
9208 /* Similar to post_error_ne, but T is a GCC tree representing the number to
9209 write. If T represents a constant, the text inside curly brackets in
9210 MSG will be output (presumably including a '^'). Otherwise it will not
9211 be output and the text inside square brackets will be output instead. */
9213 void
9215 {
9222 {
9225 }
9226 else
9230 {
9236 ;
9237 else
9239 }
9244 }
9246 /* Similar to post_error_ne_tree, but NUM is a second integer to write. */
9248 void
9251 {
9254 }
9255 \f
9256 /* Initialize the table that maps GNAT codes to GCC codes for simple
9257 binary and unary operations. */
9259 static void
9261 {
9287 }
9289 /* Return a label to branch to for the exception type in KIND or NULL_TREE
9290 if none. */
9292 tree
9294 {
9301 else
9303 }
9305 /* Return the decl for the current elaboration procedure. */
9307 tree
9309 {
9311 }