| blob | 2d0e9ffd54f7c5c8931ab7f3c841296a235163c9 |
1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * T R A N S *
6 * *
7 * C Implementation File *
8 * *
9 * *
10 * Copyright (C) 1992-2003, Free Software Foundation, Inc. *
11 * *
12 * GNAT is free software; you can redistribute it and/or modify it under *
13 * terms of the GNU General Public License as published by the Free Soft- *
14 * ware Foundation; either version 2, or (at your option) any later ver- *
15 * sion. GNAT is distributed in the hope that it will be useful, but WITH- *
16 * OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY *
17 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License *
18 * for more details. You should have received a copy of the GNU General *
19 * Public License distributed with GNAT; see file COPYING. If not, write *
20 * to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, *
21 * MA 02111-1307, USA. *
22 * *
23 * GNAT was originally developed by the GNAT team at New York University. *
24 * Extensive contributions were provided by Ada Core Technologies Inc. *
25 * *
26 ****************************************************************************/
69 /* Current filename without path. */
72 /* Flag indicating whether file names are discarded in exception messages */
75 /* If true, then gigi is being called on an analyzed but unexpanded
76 tree, and the only purpose of the call is to properly annotate
77 types with representation information. */
80 /* List of TREE_LIST nodes representing a block stack. TREE_VALUE
81 of each gives the variable used for the setjmp buffer in the current
82 block, if any. TREE_PURPOSE gives the bottom condition for a loop,
83 if this block is for a loop. The latter is only used to save the tree
84 over GC. */
85 tree gnu_block_stack;
87 /* List of TREE_LIST nodes representing a stack of exception pointer
88 variables. TREE_VALUE is the VAR_DECL that stores the address of
89 the raised exception. Nonzero means we are in an exception
90 handler. Not used in the zero-cost case. */
93 /* List of TREE_LIST nodes containing pending elaborations lists.
94 used to prevent the elaborations being reclaimed by GC. */
97 /* Map GNAT tree codes to GCC tree codes for simple expressions. */
100 /* Current node being treated, in case gigi_abort called. */
101 Node_Id error_gnat_node;
103 /* Variable that stores a list of labels to be used as a goto target instead of
104 a return in some functions. See processing for N_Subprogram_Body. */
128 /* Constants for +0.5 and -0.5 for float-to-integer rounding. */
131 \f
132 /* This is the main program of the back-end. It sets up all the table
133 structures and then generates code. */
135 void
140 Node_Id gnat_root;
151 Int number_units ATTRIBUTE_UNUSED;
153 Entity_Id standard_integer;
154 Entity_Id standard_long_long_float;
155 Entity_Id standard_exception_type;
156 Int gigi_operating_mode;
157 {
158 tree gnu_standard_long_long_float;
159 tree gnu_standard_exception_type;
174 /* See if we should discard file names in exception messages. */
182 /* Initialize ourselves. */
187 /* Enable GNAT stack checking method if needed */
191 /* Save the type we made for integer as the type for Standard.Integer.
192 Then make the rest of the standard types. Note that some of these
193 may be subtypes. */
202 gnu_standard_long_long_float
204 gnu_standard_exception_type
209 /* Process any Pragma Ident for the main unit. */
210 #ifdef ASM_OUTPUT_IDENT
212 ASM_OUTPUT_IDENT
215 #endif
217 /* If we are using the GCC exception mechanism, let GCC know. */
222 }
224 \f
225 /* This function is the driver of the GNAT to GCC tree transformation process.
226 GNAT_NODE is the root of some gnat tree. It generates code for that
227 part of the tree. */
229 void
231 Node_Id gnat_node;
232 {
233 tree gnu_root;
235 /* Save node number in case error */
240 /* This should just generate code, not return a value. If it returns
241 a value, something is wrong. */
244 }
246 /* GNAT_NODE is the root of some GNAT tree. Return the root of the GCC
247 tree corresponding to that GNAT tree. Normally, no code is generated.
248 We just return an equivalent tree which is used elsewhere to generate
249 code. */
251 tree
253 Node_Id gnat_node;
254 {
255 tree gnu_root;
257 /* Save node number in case error */
262 /* If we got no code as a result, something is wrong. */
267 }
268 \f
269 /* This function is the driver of the GNAT to GCC tree transformation process.
270 It is the entry point of the tree transformer. GNAT_NODE is the root of
271 some GNAT tree. Return the root of the corresponding GCC tree or
272 error_mark_node to signal that there is no GCC tree to return.
274 The latter is the case if only code generation actions have to be performed
275 like in the case of if statements, loops, etc. This routine is wrapped
276 in the above two routines for most purposes. */
278 static tree
280 Node_Id gnat_node;
281 {
284 tree gnu_expr;
286 Node_Id gnat_temp;
287 Entity_Id gnat_temp_type;
289 /* Set input_file_name and lineno from the Sloc in the GNAT tree. */
292 /* If this is a Statement and we are at top level, we add the statement
293 as an elaboration for a null tree. That will cause it to be placed
294 in the elaboration procedure. */
307 {
311 }
313 /* If this node is a non-static subexpression and we are only
314 annotating types, make this into a NULL_EXPR for non-VOID types
315 and error_mark_node for void return types. But allow
316 N_Identifier since we use it for lots of things, including
317 getting trees for discriminants. */
323 {
328 else
331 }
334 {
335 /********************************/
336 /* Chapter 2: Lexical Elements: */
337 /********************************/
344 /* If the Etype of this node does not equal the Etype of the
345 Entity, something is wrong with the entity map, probably in
346 generic instantiation. However, this does not apply to
347 types. Since we sometime have strange Ekind's, just do
348 this test for objects. Also, if the Etype of the Entity
349 is private, the Etype of the N_Identifier is allowed to be the
350 full type and also we consider a packed array type to be the
351 same as the original type. Finally, if the types are Itypes,
352 one may be a copy of the other, which is also legal. */
375 /* If this is a reference to a deferred constant whose partial view
376 is an unconstrained private type, the proper type is on the full
377 view of the constant, not on the full view of the type, which may
378 be unconstrained.
380 This may be a reference to a type, for example in the prefix of the
381 attribute Position, generated for dispatching code (see Make_DT in
382 exp_disp,adb). In that case we need the type itself, not is parent,
383 in particular if it is a derived type */
389 {
393 }
394 else
395 {
396 /* Expand the type of this identitier first, in case it is
397 an enumeral literal, which only get made when the type
398 is expanded. There is no order-of-elaboration issue here.
399 We want to use the Actual_Subtype if it has already been
400 elaborated, otherwise the Etype. Avoid using Actual_Subtype
401 for packed arrays to simplify things. */
409 else
413 }
417 /* If we are in an exception handler, force this variable into memory
418 to ensure optimization does not remove stores that appear
419 redundant but are actually needed in case an exception occurs.
421 ??? Note that we need not do this if the variable is declared within
422 the handler, only if it is referenced in the handler and declared
423 in an enclosing block, but we have no way of testing that
424 right now. */
426 {
429 }
431 /* Some objects (such as parameters passed by reference, globals of
432 variable size, and renamed objects) actually represent the address
433 of the object. In that case, we must do the dereference. Likewise,
434 deal with parameters to foreign convention subprograms. Call fold
435 here since GNU_RESULT may be a CONST_DECL. */
440 {
446 gnu_result);
451 }
453 /* The GNAT tree has the type of a function as the type of its result.
454 Also use the type of the result if the Etype is a subtype which
455 is nominally unconstrained. But remove any padding from the
456 resulting type. */
459 {
464 }
466 /* We always want to return the underlying INTEGER_CST for an
467 enumeration literal to avoid the need to call fold in lots
468 of places. But don't do this is the parent will be taking
469 the address of this object. */
471 {
485 }
489 {
490 tree gnu_type;
492 /* Get the type of the result, looking inside any padding and
493 left-justified modular types. Then get the value in that type. */
502 /* If the result overflows (meaning it doesn't fit in its base type),
503 abort. We would like to check that the value is within the range
504 of the subtype, but that causes problems with subtypes whose usage
505 will raise Constraint_Error and with biased representation, so
506 we don't. */
509 }
513 /* If a Entity is present, it means that this was one of the
514 literals in a user-defined character type. In that case,
515 just return the value in the CONST_DECL. Otherwise, use the
516 character code. In that case, the base type should be an
517 INTEGER_TYPE, but we won't bother checking for that. */
521 else
527 /* If this is of a fixed-point type, the value we want is the
528 value of the corresponding integer. */
530 {
533 gnu_result_type);
535 )
537 }
538 /* We should never see a Vax_Float type literal, since the front end
539 is supposed to transform these using appropriate conversions */
543 else
544 {
549 /* If the real value is zero, so is the result. Otherwise,
550 convert it to a machine number if it isn't already. That
551 forces BASE to 0 or 2 and simplifies the rest of our logic. */
554 else
555 {
557 ur_realval
561 gnu_result
564 /* If we have a base of zero, divide by the denominator.
565 Otherwise, the base must be 2 and we scale the value, which
566 we know can fit in the mantissa of the type (hence the use
567 of that type above). */
569 gnu_result
572 gnu_result,
574 gnu_result_type));
578 else
579 {
580 REAL_VALUE_TYPE tmp;
585 }
586 }
588 /* Now see if we need to negate the result. Do it this way to
589 properly handle -0. */
591 gnu_result
593 gnu_result);
594 }
601 {
602 /* We assume here that all strings are of type standard.string.
603 "Weird" types of string have been converted to an aggregate
604 by the expander. */
610 /* Build the string with the characters in the literal. Note
611 that Ada strings are 1-origin. */
615 /* Put a null at the end of the string in case it's in a context
616 where GCC will want to treat it as a C string. */
621 /* Strings in GCC don't normally have types, but we want
622 this to not be converted to the array type. */
624 }
625 else
626 {
627 /* Build a list consisting of each character, then make
628 the aggregate. */
635 gnu_list
641 gnu_list);
643 gnu_result
645 }
652 /* Check for (and ignore) unrecognized pragma */
657 {
659 /* Do nothing at top level: all such variables are already
660 viewable. */
668 {
676 }
682 {
696 }
703 }
706 /**************************************/
707 /* Chapter 3: Declarations and Types: */
708 /**************************************/
723 /* If we are just annotating types and this object has an unconstrained
724 or task type, don't elaborate it. */
735 && (! type_annotate_only
737 {
742 /* If this object has its elaboration delayed, we must force
743 evaluation of GNU_EXPR right now and save it for when the object
744 is frozen. */
746 {
749 gnu_expr
753 else
757 }
758 }
759 else
774 /* Don't do anything if this renaming is handled by the front end.
775 or if we are just annotating types and this object has a
776 composite or task type, don't elaborate it. */
778 && ! (type_annotate_only
782 {
785 }
796 /* These are fully handled in the front end. */
799 /*************************************/
800 /* Chapter 4: Names and Expressions: */
801 /*************************************/
807 /* Emit access check if necessary */
815 {
817 tree gnu_type;
822 /* Emit access check if necessary */
829 /* If we got a padded type, remove it too. */
832 gnu_array_object
834 gnu_array_object);
838 /* First compute the number of dimensions of the array, then
839 fill the expression array, the order depending on whether
840 this is a Convention_Fortran array or not. */
845 ;
854 else
862 {
870 gnu_expr
871 = emit_index_check
878 }
879 }
885 {
886 tree gnu_type;
892 /* Emit access check if necessary */
896 /* Do any implicit dereferences of the prefix and do any needed
897 range check. */
902 {
903 /* Get the bounds of the slice. */
904 tree gnu_index_type
910 /* Check to see that the minimum slice value is in range */
911 gnu_expr_l
912 = emit_index_check
917 /* Check to see that the maximum slice value is in range */
918 gnu_expr_h
919 = emit_index_check
924 /* Derive a good type to convert everything too */
927 /* Build a compound expression that does the range checks */
928 gnu_expr
933 /* Build a conditional expression that returns the range checks
934 expression if the slice range is not null (max >= min) or
935 returns the min if the slice range is null */
936 gnu_expr
940 gnu_max_expr),
942 gnu_min_expr)),
944 }
945 else
950 }
954 {
958 tree gnu_field;
962 {
967 }
974 /* For discriminant references in tagged types always substitute the
975 corresponding discriminant as the actual selected component. */
981 /* For discriminant references of untagged types always substitute the
982 corresponding girder discriminant. */
987 /* Handle extracting the real or imaginary part of a complex.
988 The real part is the first field and the imaginary the last. */
994 else
995 {
998 /* If there are discriminants, the prefix might be
999 evaluated more than once, which is a problem if it has
1000 side-effects. */
1007 /* Emit discriminant check if necessary. */
1010 gnu_result
1012 }
1018 }
1022 {
1023 /* The attribute designator (like an enumeration value). */
1026 tree gnu_prefix;
1027 tree gnu_type;
1029 /* The Elab_Spec and Elab_Body attributes are special in that
1030 Prefix is a unit, not an object with a GCC equivalent. Similarly
1031 for Elaborated, since that variable isn't otherwise known. */
1033 {
1034 gnu_prefix
1035 = create_subprog_decl
1037 attribute == Attr_Elab_Body
1041 }
1046 /* If the input is a NULL_EXPR, make a new one. */
1048 {
1053 }
1056 {
1059 /* These are just conversions until since representation
1060 clauses for enumerations are handled in the front end. */
1061 {
1068 }
1073 /* These just add or subject the constant 1. Representation
1074 clauses for enumerations are handled in the front-end. */
1079 {
1081 gnu_expr
1082 = emit_check
1084 gnu_expr,
1085 attribute == Attr_Pred
1089 }
1091 gnu_result
1101 /* Conversions don't change something's address but can cause
1102 us to miss the COMPONENT_REF case below, so strip them off. */
1103 gnu_prefix
1107 /* If we are taking 'Address of an unconstrained object,
1108 this is the pointer to the underlying array. */
1111 /* ... fall through ... */
1118 gnu_result
1125 /* For 'Code_Address, find an inner ADDR_EXPR and mark it
1126 so that we don't try to build a trampoline. */
1128 {
1134 ;
1138 }
1149 /* Remove NOPS from gnu_expr and conversions from gnu_prefix.
1150 We only use GNU_EXPR to see if a COMPONENT_REF was involved. */
1158 /* Replace an unconstrained array type with the type of the
1159 underlying array. We can't do this with a call to
1160 maybe_unconstrained_array since we may have a TYPE_DECL.
1161 For 'Max_Size_In_Storage_Elements, use the record type
1162 that will be used to allocate the object and its template. */
1165 {
1169 }
1171 /* If we are looking for the size of a field, return the
1172 field size. Otherwise, if the prefix is an object,
1173 or if 'Object_Size or 'Max_Size_In_Storage_Elements has
1174 been specified, the result is the GCC size of the type.
1175 Otherwise, the result is the RM_Size of the type. */
1181 {
1182 /* If this is a padded type, the GCC size isn't relevant
1183 to the programmer. Normally, what we want is the RM_Size,
1184 which was set from the specified size, but if it was not
1185 set, we want the size of the relevant field. Using the MAX
1186 of those two produces the right result in all case. Don't
1187 use the size of the field if it's a self-referential type,
1188 since that's never what's wanted. */
1192 {
1196 gnu_result
1199 }
1200 else
1202 }
1203 else
1209 /* Deal with a self-referential size by returning the maximum
1210 size for a type and by qualifying the size with
1211 the object for 'Size of an object. */
1215 {
1219 else
1221 }
1223 /* If the type contains a template, subtract the size of the
1224 template. */
1230 /* If the type contains a template, subtract the size of the
1231 template. */
1239 /* Always perform division using unsigned arithmetic as the
1240 size cannot be negative, but may be an overflowed positive
1241 value. This provides correct results for sizes up to 512 MB.
1242 ??? Size should be calculated in storage elements directly. */
1247 gnu_result,
1248 bitsize_unit_node)));
1255 && (TYPE_IS_PADDING_P
1264 gnu_result
1266 else
1277 {
1284 else
1285 gnu_result
1286 = build_binary_op
1288 build_binary_op
1300 }
1301 /* ... fall through ... */
1303 {
1304 int Dimension
1309 /* Emit access check if necessary */
1313 /* Make sure any implicit dereference gets done. */
1321 {
1323 tree gnu_type_temp;
1329 ;
1332 }
1341 gnu_result
1344 gnu_result
1346 else
1347 /* 'Length or 'Range_Length. */
1348 {
1349 tree gnu_compute_type
1350 = gnat_signed_or_unsigned_type
1353 gnu_result
1354 = build_binary_op
1356 build_binary_op
1358 build_binary_op
1361 TYPE_MAX_VALUE
1364 TYPE_MIN_VALUE
1368 }
1370 /* If this has a PLACEHOLDER_EXPR, qualify it by the object
1371 we are handling. Note that these attributes could not
1372 have been used on an unconstrained array type. */
1379 }
1386 {
1387 HOST_WIDE_INT bitsize;
1388 HOST_WIDE_INT bitpos;
1389 tree gnu_offset;
1390 tree gnu_field_bitpos;
1391 tree gnu_field_offset;
1392 tree gnu_inner;
1400 /* We can have 'Bit on any object, but if it isn't a
1401 COMPONENT_REF, the result is zero. Do not allow
1402 'Bit on a bare component, though. */
1406 {
1409 }
1420 {
1421 gnu_field_bitpos
1423 gnu_field_offset
1430 {
1431 gnu_field_bitpos
1435 gnu_field_offset
1439 }
1440 }
1442 {
1445 }
1446 else
1447 {
1450 }
1453 {
1465 gnu_result
1469 bitsize_one_node);
1475 }
1477 /* If this has a PLACEHOLDER_EXPR, qualify it by the object
1478 we are handling. */
1485 }
1508 && (TYPE_IS_PADDING_P
1516 gnu_type
1526 /* Note this size cannot be self-referential. */
1533 /* This is just a zero cast to the pointer type for
1534 our prefix and dereferenced. */
1536 gnu_result
1539 integer_zero_node));
1544 {
1551 {
1556 ;
1557 }
1563 || (DECL_BY_COMPONENT_PTR_P
1567 }
1571 /* Say we have an unimplemented attribute. Then set the
1572 value to be returned to be a zero and hope that's something
1573 we can convert to the type of this attribute. */
1579 }
1581 /* If this is an attribute where the prefix was unused,
1582 force a use of it if it has a side-effect. But don't do it if
1583 the prefix is just an entity name. However, if an access check
1584 is needed, we must do it. See second example in AARM 11.6(5.e). */
1590 }
1594 /* Like 'Access as far as we are concerned. */
1602 {
1603 tree gnu_aggr_type;
1605 /* ??? It is wrong to evaluate the type now, but there doesn't
1606 seem to be any other practical way of doing it. */
1608 gnu_aggr_type = gnu_result_type
1613 gnu_aggr_type
1620 gnu_result
1622 gnu_aggr_type);
1624 {
1625 /* The first element is the discrimant, which we ignore. The
1626 next is the field we're building. Convert the expression
1627 to the type of the field and then to the union type. */
1628 Node_Id gnat_assoc
1631 tree gnu_field_type
1636 }
1639 gnu_aggr_type,
1642 gnu_result
1643 = build_binary_op
1648 (Next
1650 else
1654 }
1664 /* Get the operand expression. */
1668 gnu_result
1680 /* If the result is a pointer type, see if we are improperly
1681 converting to a stricter alignment. */
1685 {
1688 unsigned int oalign
1693 post_error_ne_tree_2
1697 }
1704 {
1707 tree gnu_low;
1708 tree gnu_high;
1710 /* GNAT_RANGE is either an N_Range node or an identifier
1711 denoting a subtype. */
1713 {
1716 }
1719 {
1724 }
1725 else
1730 /* If LOW and HIGH are identical, perform an equality test.
1731 Otherwise, ensure that GNU_OBJECT is only evaluated once
1732 and perform a full range test. */
1736 else
1737 {
1739 gnu_result
1745 }
1749 }
1757 ? RDIV_EXPR
1764 {
1766 tree gnu_rhs_side;
1768 /* The elaboration of the RHS may generate code. If so,
1769 we need to make sure it gets executed after the LHS. */
1779 gnu_rhs);
1782 }
1786 /* These can either be operations on booleans or on modular types.
1787 Fall through for boolean types since that's the way GNU_CODES is
1788 set up. */
1790 Modular_Integer_Kind))
1791 {
1792 enum tree_code code
1803 }
1805 /* ... fall through ... */
1816 {
1818 tree gnu_type;
1824 /* If this is a comparison operator, convert any references to
1825 an unconstrained array value into a reference to the
1826 actual array. */
1828 {
1831 }
1833 /* If the result type is a private type, its full view may be a
1834 numeric subtype. The representation we need is that of its base
1835 type, given that it is the result of an arithmetic operation. */
1837 gnu_type = gnu_result_type
1840 /* If this is a shift whose count is not guaranteed to be correct,
1841 we need to adjust the shift count. */
1844 {
1846 tree gnu_max_shift
1854 gnu_rhs
1855 = build_binary_op
1858 gnu_count_type,
1859 gnu_max_shift,
1861 integer_one_node)),
1862 gnu_rhs);
1863 }
1865 /* For right shifts, the type says what kind of shift to do,
1866 so we may need to choose a different type. */
1875 {
1878 }
1882 /* If this is a logical shift with the shift count not verified,
1883 we must return zero if it is too large. We cannot compensate
1884 above in this case. */
1888 gnu_result
1889 = build_cond_expr
1892 gnu_rhs,
1896 gnu_result);
1897 }
1901 {
1904 tree gnu_false
1911 }
1920 /* This case can apply to a boolean or a modular type.
1921 Fall through for a boolean operand since GNU_CODES is set
1922 up to handle this. */
1924 {
1928 gnu_expr);
1930 }
1932 /* ... fall through ... */
1939 else
1948 {
1950 tree gnu_type;
1954 /* The Expression operand can either be an N_Identifier or
1955 Expanded_Name, which must represent a type, or a
1956 N_Qualified_Expression, which contains both the object type and an
1957 initial value for the object. */
1962 {
1963 Entity_Id gnat_desig_type
1974 {
1977 }
1978 else
1979 {
1985 }
1986 }
1987 else
1994 }
1997 /***************************/
1998 /* Chapter 5: Statements: */
1999 /***************************/
2003 {
2009 /* If this is the first label of an exception handler, we must
2010 mark that any CALL_INSN can jump to it. */
2014 nonlocal_goto_handler_labels
2016 nonlocal_goto_handler_labels);
2017 }
2027 /* Get the LHS and RHS of the statement and convert any reference to an
2028 unconstrained array into a reference to the underlying array. */
2030 gnu_rhs
2035 /* If range check is needed, emit code to generate it */
2039 /* If either side's type has a size that overflows, convert this
2040 into raise of Storage_Error: execution shouldn't have gotten
2041 here anyway. */
2047 else
2053 /* Start an IF statement giving the condition. */
2058 /* Generate code for the statements to be executed if the condition
2059 is true. */
2066 /* Generate each of the "else if" parts. */
2068 {
2072 {
2073 Node_Id gnat_statement;
2077 /* Set up the line numbers for each condition we test. */
2085 }
2086 }
2088 /* Finally, handle any statements in the "else" part. */
2090 {
2097 }
2103 {
2104 Node_Id gnat_when;
2105 Node_Id gnat_choice;
2106 tree gnu_label;
2107 Node_Id gnat_statement;
2118 {
2119 /* First compile all the different case choices for the current
2120 WHEN alternative. */
2124 {
2131 {
2133 /* Abort on all errors except range empty, which
2134 means we ignore this alternative. */
2135 error_code
2145 error_code
2146 = pushcase_range
2159 /* This represents either a subtype range or a static value
2160 of some kind; Ekind says which. If a static value,
2161 fall through to the next case. */
2163 {
2166 error_code
2174 }
2175 /* ... fall through ... */
2190 }
2191 }
2193 /* After compiling the choices attached to the WHEN compile the
2194 body of statements that have to be executed, should the
2195 "WHEN ... =>" be taken. Push a binding level here in case
2196 variables are declared since we want them to be local to this
2197 set of statements instead of the block containing the Case
2198 statement. */
2206 /* Communicate to GCC that we are done with the current WHEN,
2207 i.e. insert a "break" statement. */
2211 }
2214 }
2218 {
2219 /* The loop variable in GCC form, if any. */
2221 /* PREINCREMENT_EXPR or PREDECREMENT_EXPR. */
2223 /* Used if this is a named loop for so EXIT can work. */
2225 /* Condition to continue loop tested at top of loop. */
2227 /* Similar, but tested at bottom of loop. */
2229 Node_Id gnat_statement;
2234 /* Set the condition that under which the loop should continue.
2235 For "LOOP .... END LOOP;" the condition is always true. */
2237 ;
2238 /* The case "WHILE condition LOOP ..... END LOOP;" */
2241 else
2242 {
2243 /* We have an iteration scheme. */
2244 Node_Id gnat_loop_spec
2256 tree gnu_limit
2260 /* We know the loop variable will not overflow if GNU_LAST is
2261 a constant and is not equal to GNU_LIMIT. If it might
2262 overflow, we have to move the limit test to the end of
2263 the loop. In that case, we have to test for an
2264 empty loop outside the loop. */
2268 {
2274 }
2276 /* Open a new nesting level that will surround the loop to declare
2277 the loop index variable. */
2281 /* Declare the loop index and set it to its initial value. */
2285 gnu_loop_var);
2287 /* The loop variable might be a padded type, so use `convert' to
2288 get a reference to the inner variable if so. */
2291 /* Set either the top or bottom exit condition as
2292 appropriate depending on whether we know an overflow
2293 cannot occur or not. */
2295 gnu_bottom_condition
2298 else
2299 gnu_top_condition
2304 }
2309 else
2312 /* If the loop was named, have the name point to this loop. In this
2313 case, the association is not a ..._DECL node; in fact, it isn't
2314 a GCC tree node at all. Since this name is referenced inside
2315 the loop, do it before we process the statements of the loop. */
2317 {
2322 }
2326 /* We must evaluate the condition after we've entered the
2327 loop so that any expression actions get done in the right
2328 place. */
2334 /* Make the loop body into its own block, so any allocated
2335 storage will be released every iteration. This is needed
2336 for stack allocation. */
2339 gnu_block_stack
2356 {
2359 gnu_loop_var,
2361 integer_one_node));
2364 }
2370 {
2371 /* Close the nesting level that sourround the loop that was used to
2372 declare the loop index variable. */
2376 }
2379 {
2382 }
2383 }
2400 {
2401 /* Which loop to exit, NULL if the current loop. */
2403 /* The GCC version of the optional GNAT condition node attached to the
2404 exit statement. Exit the loop if this is false. */
2408 loop_id
2417 }
2424 {
2425 /* The gnu function type of the subprogram currently processed. */
2427 /* The return value from the subprogram. */
2430 /* If we are dealing with a "return;" from an Ada procedure with
2431 parameters passed by copy in copy out, we need to return a record
2432 containing the final values of these parameters. If the list
2433 contains only one entry, return just that entry.
2435 For a full description of the copy in copy out parameter mechanism,
2436 see the part of the gnat_to_gnu_entity routine dealing with the
2437 translation of subprograms.
2439 But if we have a return label defined, convert this into
2440 a branch to that label. */
2446 {
2449 else
2450 gnu_ret_val
2453 }
2455 /* If the Ada subprogram is a function, we just need to return the
2456 expression. If the subprogram returns an unconstrained
2457 array, we have to allocate a new version of the result and
2458 return it. If we return by reference, return a pointer. */
2461 {
2464 /* Do not remove the padding from GNU_RET_VAL if the inner
2465 type is self-referential since we want to allocate the fixed
2466 size in that case. */
2468 && (TYPE_IS_PADDING_P
2470 && contains_placeholder_p
2479 {
2482 /* We have two cases: either the function returns with
2483 depressed stack or not. If not, we allocate on the
2484 secondary stack. If so, we allocate in the stack frame.
2485 if no copy is needed, the front end will set By_Ref,
2486 which we handle in the case above. */
2488 gnu_ret_val
2491 else
2492 gnu_ret_val
2497 }
2498 }
2504 gnu_ret_val));
2505 else
2508 }
2521 /****************************/
2522 /* Chapter 6: Subprograms: */
2523 /****************************/
2526 /* Unless there is a freeze node, declare the subprogram. We consider
2527 this a "definition" even though we're not generating code for
2528 the subprogram because we will be making the corresponding GCC
2529 node here. */
2538 /* This subprogram doesn't exist for code generation purposes, but we
2539 have to elaborate the types of any parameters, unless they are
2540 imported types (nothing to generate in this case). */
2552 /* For a child unit identifier go up a level to get the
2553 specificaton. We get this when we try to find the spec of
2554 a child unit package that is the compilation unit being compiled. */
2559 {
2560 /* Save debug output mode in case it is reset. */
2563 /* Definining identifier of a parameter to the subprogram. */
2564 Entity_Id gnat_param;
2565 /* The defining identifier for the subprogram body. Note that if a
2566 specification has appeared before for this body, then the identifier
2567 occurring in that specification will also be a defining identifier
2568 and all the calls to this subprogram will point to that
2569 specification. */
2570 Entity_Id gnat_subprog_id
2574 /* The FUNCTION_DECL node corresponding to the subprogram spec. */
2575 tree gnu_subprog_decl;
2576 /* The FUNCTION_TYPE node corresponding to the subprogram spec. */
2577 tree gnu_subprog_type;
2578 tree gnu_cico_list;
2580 /* If this is a generic object or if it has been eliminated,
2581 ignore it. */
2588 /* If debug information is suppressed for the subprogram,
2589 turn debug mode off for the duration of processing. */
2591 {
2594 }
2596 /* If this subprogram acts as its own spec, define it. Otherwise,
2597 just get the already-elaborated tree node. However, if this
2598 subprogram had its elaboration deferred, we will already have
2599 made a tree node for it. So treat it as not being defined in
2600 that case. Such a subprogram cannot have an address clause or
2601 a freeze node, so this test is safe, though it does disable
2602 some otherwise-useful error checking. */
2603 gnu_subprog_decl
2610 /* Set the line number in the decl to correspond to that of
2611 the body so that the line number notes are written
2612 correctly. */
2625 /* If there are OUT parameters, we need to ensure that the
2626 return statement properly copies them out. We do this by
2627 making a new block and converting any inner return into a goto
2628 to a label at the end of the block. */
2631 {
2632 gnu_return_label_stack
2635 gnu_return_label_stack);
2638 }
2639 else
2640 gnu_return_label_stack
2643 /* See if there are any parameters for which we don't yet have
2644 GCC entities. These must be for OUT parameters for which we
2645 will be making VAR_DECL nodes here. Fill them in to
2646 TYPE_CI_CO_LIST, which must contain the empty entry as well.
2647 We can match up the entries because TYPE_CI_CO_LIST is in the
2648 order of the parameters. */
2655 else
2656 {
2657 /* Skip any entries that have been already filled in; they
2658 must correspond to IN OUT parameters. */
2661 ;
2663 /* Do any needed references for padded types. */
2667 }
2671 /* Generate the code of the subprogram itself. A return statement
2672 will be present and any OUT parameters will be handled there. */
2680 {
2681 tree gnu_retval;
2691 else
2693 gnu_cico_list);
2696 gnu_retval
2699 expand_return
2702 gnu_retval));
2704 }
2708 /* Disconnect the trees for parameters that we made variables for
2709 from the GNAT entities since these will become unusable after
2710 we end the function. */
2721 }
2730 {
2731 /* The GCC node corresponding to the GNAT subprogram name. This can
2732 either be a FUNCTION_DECL node if we are dealing with a standard
2733 subprogram call, or an indirect reference expression (an
2734 INDIRECT_REF node) pointing to a subprogram. */
2736 /* The FUNCTION_TYPE node giving the GCC type of the subprogram. */
2738 tree gnu_subprog_addr
2740 Entity_Id gnat_formal;
2741 Node_Id gnat_actual;
2745 tree gnu_subprog_call;
2748 {
2756 }
2761 /* If we are calling a stubbed function, make this into a
2762 raise of Program_Error. Elaborate all our args first. */
2766 {
2773 {
2775 gnu_result
2778 }
2779 else
2780 expand_expr_stmt
2783 }
2785 /* The only way we can be making a call via an access type is
2786 if Name is an explicit dereference. In that case, get the
2787 list of formal args from the type the access type is pointing
2788 to. Otherwise, get the formals from entity being called. */
2792 /* Assume here that this must be 'Elab_Body or 'Elab_Spec. */
2794 else
2797 /* Create the list of the actual parameters as GCC expects it, namely
2798 a chain of TREE_LIST nodes in which the TREE_VALUE field of each
2799 node is a parameter-expression and the TREE_PURPOSE field is
2800 null. Skip OUT parameters that are not passed by reference. */
2806 {
2808 Node_Id gnat_name
2813 tree gnu_actual;
2815 /* If it's possible we may need to use this expression twice,
2816 make sure than any side-effects are handled via SAVE_EXPRs.
2817 Likewise if we need to force side-effects before the call.
2818 ??? This is more conservative than we need since we don't
2819 need to do this for pass-by-ref with no conversion.
2820 If we are passing a non-addressable Out or In Out parameter by
2821 reference, pass the address of a copy and set up to copy back
2822 out after the call. */
2825 {
2832 {
2835 /* Remove any unpadding on the actual and make a copy.
2836 But if the actual is a left-justified modular type,
2837 first convert to it. */
2839 && (TYPE_IS_PADDING_P
2843 && (TYPE_LEFT_JUSTIFIED_MODULAR_P
2849 /* Set up to move the copy back to the original. */
2851 gnu_after_list);
2854 }
2855 }
2857 /* If this was a procedure call, we may not have removed any
2858 padding. So do it here for the part we will use as an
2859 input, if any. */
2865 gnu_actual);
2872 /* Do any needed conversions. We need only check for
2873 unchecked conversion since normal conversions will be handled
2874 by just converting to the formal type. */
2876 {
2877 gnu_actual
2879 gnu_actual);
2881 /* One we've done the unchecked conversion, we still
2882 must ensure that the object is in range of the formal's
2883 type. */
2888 }
2889 else
2890 /* We may have suppressed a conversion to the Etype of the
2891 actual since the parent is a procedure call. So add the
2892 conversion here. */
2894 gnu_actual);
2898 /* If we have not saved a GCC object for the formal, it means
2899 it is an OUT parameter not passed by reference. Otherwise,
2900 look at the PARM_DECL to see if it is passed by reference. */
2904 {
2906 {
2909 /* If we have a padded type, be sure we've removed the
2910 padding. */
2913 gnu_actual
2915 gnu_actual);
2916 }
2918 /* The symmetry of the paths to the type of an entity is
2919 broken here since arguments don't know that they will
2920 be passed by ref. */
2923 gnu_actual);
2924 }
2928 {
2935 {
2936 gnu_formal_type
2939 }
2941 /* Take the address of the object and convert to the
2942 proper pointer type. We'd like to actually compute
2943 the address of the beginning of the array using
2944 an ADDR_EXPR of an ARRAY_REF, but there's a possibility
2945 that the ARRAY_REF might return a constant and we'd
2946 be getting the wrong address. Neither approach is
2947 exactly correct, but this is the most likely to work
2948 in all cases. */
2951 gnu_actual));
2952 }
2956 {
2957 /* If arg is 'Null_Parameter, pass zero descriptor. */
2961 gnu_actual
2963 integer_zero_node);
2964 else
2965 gnu_actual
2968 gnat_formal));
2969 }
2970 else
2971 {
2975 gnu_name_list
2983 /* If this is 'Null_Parameter, pass a zero even though we are
2984 dereferencing it. */
2989 BITS_PER_WORD))
2990 gnu_actual
2991 = unchecked_convert
2995 integer_zero_node));
2996 else
2997 gnu_actual
3000 gnu_actual);
3001 }
3003 gnu_actual_list
3006 }
3010 NULL_TREE);
3013 /* If it is a function call, the result is the call expression. */
3015 {
3018 /* If the function returns an unconstrained array or by reference,
3019 we have to de-dereference the pointer. */
3023 gnu_result);
3026 }
3028 /* If this is the case where the GNAT tree contains a procedure call
3029 but the Ada procedure has copy in copy out parameters, the special
3030 parameter passing mechanism must be used. */
3032 {
3033 /* List of FIELD_DECLs associated with the PARM_DECLs of the copy
3034 in copy out parameters. */
3039 {
3040 tree gnu_name;
3044 /* If any of the names had side-effects, ensure they are
3045 all evaluated before the call. */
3049 gnu_subprog_call
3052 }
3056 else
3063 /* If we are dealing with a copy in copy out parameter, we must
3064 retrieve its value from the record returned in the function
3065 call. */
3069 || (DECL_BY_COMPONENT_PTR_P
3073 {
3074 /* Get the value to assign to this OUT or IN OUT
3075 parameter. It is either the result of the function if
3076 there is only a single such parameter or the appropriate
3077 field from the record returned. */
3078 tree gnu_result
3080 : build_component_ref
3083 int unchecked_conversion
3085 /* If the actual is a conversion, get the inner expression,
3086 which will be the real destination, and convert the
3087 result to the type of the actual parameter. */
3088 tree gnu_actual
3091 /* If the result is a padded type, remove the padding. */
3094 gnu_result
3097 gnu_result);
3099 /* If the result is a type conversion, do it. */
3101 gnu_result
3102 = convert_with_check
3109 gnu_result
3111 else
3112 {
3122 gnu_result);
3123 }
3130 }
3131 }
3132 else
3133 {
3136 }
3138 /* Handle anything we need to assign back. */
3140 gnu_expr;
3145 }
3148 /*************************/
3149 /* Chapter 7: Packages: */
3150 /*************************/
3164 /* If this is the body of a generic package - do nothing */
3171 {
3175 }
3178 /*********************************/
3179 /* Chapter 8: Visibility Rules: */
3180 /*********************************/
3184 /* Nothing to do here - but these may appear in list of declarations */
3187 /***********************/
3188 /* Chapter 9: Tasks: */
3189 /***********************/
3198 /***********************************************************/
3199 /* Chapter 10: Program Structure and Compilation Issues: */
3200 /***********************************************************/
3204 /* For a body, first process the spec if there is one. */
3213 {
3220 };
3227 /* Process any pragmas following the unit. */
3233 /* Put all the Actions into the elaboration routine if we already had
3234 elaborations. This will happen anyway if they are statements, but we
3235 want to force declarations there too due to order-of-elaboration
3236 issues. Most should have Is_Statically_Allocated set. If we
3237 have had no elaborations, we have no order-of-elaboration issue and
3238 don't want to create elaborations here. */
3242 {
3246 else
3248 }
3250 /* Generate elaboration code for this unit, if necessary, and
3251 say whether we did or not. */
3252 Set_Has_No_Elaboration_Code
3254 build_unit_elab
3266 /* Simply process whatever unit is being inserted. */
3274 /***************************/
3275 /* Chapter 11: Exceptions: */
3276 /***************************/
3280 /* The GCC exception handling mechanism can handle both ZCX and SJLJ
3281 schemes and we have our own SJLJ mechanism. To call the GCC
3282 mechanism, we first call expand_eh_region_start if there is at least
3283 one handler associated with the region. We then generate code for
3284 the region and call expand_start_all_catch to announce that the
3285 associated handlers are going to be generated.
3287 For each handler we call expand_start_catch, generate code for the
3288 handler, and then call expand_end_catch.
3290 After all the handlers, we call expand_end_all_catch.
3292 Here we deal with the region level calls and the
3293 N_Exception_Handler branch deals with the handler level calls
3294 (start_catch/end_catch).
3296 ??? The region level calls down there have been specifically put in
3297 place for a ZCX context and currently the order in which things are
3298 emitted (region/handlers) is different from the SJLJ case. Instead of
3299 putting other calls with different conditions at other places for the
3300 SJLJ case, it seems cleaner to reorder things for the SJLJ case and
3301 generalize the condition to make it not ZCX specific. */
3303 /* Tell the back-end we are starting a new exception region if
3304 necessary. */
3310 /* If there are exception handlers, start a new binding level that
3311 we can exit (since each exception handler will do so). Then
3312 declare a variable to save the old __gnat_jmpbuf value and a
3313 variable for our jmpbuf. Call setjmp and handle each of the
3314 possible exceptions if it returns one. */
3317 {
3321 tree gnu_cleanup_decl;
3327 {
3328 gnu_jmpsave_decl
3330 jmpbuf_ptr_type,
3339 }
3341 /* See if we are to call a function when exiting this block. */
3343 {
3344 gnu_cleanup_call
3347 gnu_cleanup_decl
3353 }
3356 {
3357 /* When we exit this block, restore the saved value. */
3360 gnu_jmpsave_decl));
3362 /* Call setjmp and handle exceptions if it returns one. */
3364 expand_start_cond
3367 gnu_jmpbuf_decl)),
3370 /* Restore our incoming longjmp value before we do anything. */
3372 gnu_jmpsave_decl));
3377 gnu_except_ptr_stack
3379 create_var_decl
3384 gnu_except_ptr_stack);
3386 /* Generate code for each exception handler. The code at
3387 N_Exception_Handler below does the real work. Note that
3388 we ignore the dummy exception handler for the identifier
3389 case, this is used only by the front end */
3397 /* If none of the exception handlers did anything, re-raise
3398 but do not defer abortion. */
3400 expand_expr_stmt
3408 /* End the "if" on setjmp. Note that we have arranged things so
3409 control never returns here. */
3412 /* This is now immediately before the body proper. Set
3413 our jmp_buf as the current buffer. */
3414 expand_expr_stmt
3417 gnu_jmpbuf_decl)));
3418 }
3419 }
3421 /* If there are no exception handlers, we must not have an at end
3422 cleanup identifier, since the cleanup identifier should always
3423 generate a corresponding exception handler, except in the case
3424 of the No_Exception_Handlers restriction, where the front-end
3425 does not generate exception handlers. */
3427 {
3429 {
3431 tree gnu_cleanup_decl;
3433 gnu_cleanup_call
3436 gnu_cleanup_decl
3442 }
3443 else
3445 }
3447 /* Generate code and declarations for the prefix of this block,
3448 if any. */
3453 /* Generate code for each statement in the block. */
3460 /* Tell the back-end we are ending the new exception region and
3461 starting the associated handlers. */
3467 /* For zero-cost exceptions, exit the block and then compile
3468 the handlers. */
3472 {
3478 }
3480 /* We don't support Front_End_ZCX in GNAT 5.0, but we don't want to
3481 crash if -gnatdX is specified. */
3485 {
3490 }
3492 /* Tell the backend when we are done with the handlers. */
3498 /* If we have handlers, close the block we made. */
3500 {
3503 }
3509 {
3510 /* Unless this is "Others" or the special "Non-Ada" exception
3511 for Ada, make an "if" statement to select the proper
3512 exceptions. For "Others", exclude exceptions where
3513 Handled_By_Others is nonzero unless the All_Others flag is set.
3514 For "Non-ada", accept an exception if "Lang" is 'V'. */
3519 {
3520 tree this_choice;
3523 {
3526 else
3527 this_choice
3528 = build_binary_op
3530 convert
3532 build_component_ref
3533 (build_unary_op
3537 integer_zero_node);
3538 }
3542 {
3543 /* ??? Note that we have to use gnat_to_gnu_entity here
3544 since the type of the exception will be wrong in the
3545 VMS case and that's exactly what this test is for. */
3546 gnu_expr
3549 /* If this was a VMS exception, check import_code
3550 against the value of the exception. */
3552 this_choice
3553 = build_binary_op
3555 build_component_ref
3556 (build_unary_op
3560 gnu_expr);
3561 else
3562 this_choice
3563 = build_binary_op
3566 convert
3570 /* If this is the distinguished exception "Non_Ada_Error"
3571 (and we are in VMS mode), also allow a non-Ada
3572 exception (a VMS condition) to match. */
3574 {
3575 tree gnu_comp
3576 = build_component_ref
3577 (build_unary_op
3582 this_choice
3583 = build_binary_op
3585 build_binary_op
3589 this_choice);
3590 }
3591 }
3592 else
3597 }
3602 }
3604 /* Tell the back end that we start an exception handler if necessary. */
3606 {
3607 /* We build a TREE_LIST of nodes representing what exception
3608 types this handler is able to catch, with special cases
3609 for others and all others cases.
3611 Each exception type is actually identified by a pointer to the
3612 exception id, with special value zero for "others" and one for
3613 "all others". Beware that these special values are known and used
3614 by the personality routine to identify the corresponding specific
3615 kinds of handlers.
3617 ??? For initial time frame reasons, the others and all_others
3618 cases have been handled using specific type trees, but this
3619 somehow hides information to the back-end, which expects NULL to
3620 be passed for catch all and end_cleanup to be used for cleanups.
3622 Care should be taken to ensure that the control flow impact of
3623 such clauses is rendered in some way. lang_eh_type_covers is
3624 doing the trick currently.
3626 ??? Should investigate the possible usage of the end_cleanup
3627 interface in this context. */
3634 {
3636 gnu_etype
3641 {
3645 }
3646 else
3649 gnu_etypes_list
3652 /* The GCC interface expects NULL to be passed for catch all
3653 handlers, so the approach below is quite tempting :
3655 if (gnu_etype == integer_zero_node)
3656 gnu_etypes_list = NULL;
3658 It would not work, however, because GCC's notion
3659 of "catch all" is stronger than our notion of "others".
3661 Until we correctly use the cleanup interface as well, the
3662 two lines above will prevent the "all others" handlers from
3663 beeing seen, because nothing can be caught beyond a catch
3664 all from GCC's point of view. */
3665 }
3668 }
3674 /* At the end of the handler, exit the block. We made this block
3675 in N_Handled_Sequence_Of_Statements. */
3678 /* Tell the back end that we're done with the current handler. */
3686 /*******************************/
3687 /* Chapter 12: Generic Units: */
3688 /*******************************/
3698 /* These nodes can appear on a declaration list but there is nothing to
3699 to be done with them. */
3702 /***************************************************/
3703 /* Chapter 13: Representation Clauses and */
3704 /* Implementation-Dependent Features: */
3705 /***************************************************/
3709 /* The only one we need deal with is for 'Address. For the others, SEM
3710 puts the information elsewhere. We need only deal with 'Address
3711 if the object has a Freeze_Node (which it never will currently). */
3716 /* Get the value to use as the address and save it as the
3717 equivalent for GNAT_TEMP. When the object is frozen,
3718 gnat_to_gnu_entity will do the right thing. */
3726 /* We do nothing with these. SEM puts the information elsewhere. */
3731 {
3737 /* First process inputs, then outputs, then clobbers. */
3740 {
3745 gnu_input_list
3748 }
3752 {
3757 gnu_orig_out_list
3759 gnu_output_list
3762 }
3766 gnu_clobber_list
3769 gnu_clobber_list);
3776 input_location);
3778 /* Copy all the intermediate outputs into the specified outputs. */
3783 {
3784 expand_expr_stmt
3789 }
3790 }
3793 /***************************************************/
3794 /* Added Nodes */
3795 /***************************************************/
3809 {
3811 tree gnu_obj_type;
3812 tree gnu_obj_size;
3815 /* If this is an unconstrained array, we know the object must
3816 have been allocated with the template in front of the object.
3817 So pass the template address, but get the total size. Do this
3818 by converting to a thin pointer. */
3820 gnu_ptr
3822 (TYPE_OBJECT_RECORD_TYPE
3824 gnu_ptr);
3832 {
3835 tree gnu_byte_offset
3842 }
3845 expand_expr_stmt
3849 }
3862 /* If the type is VOID, this is a statement, so we need to
3863 generate the code for the call. Handle a Condition, if there
3864 is one. */
3866 {
3876 }
3877 else
3881 /* Nothing to do, since front end does all validation using the
3882 values that Gigi back-annotates. */
3895 }
3897 /* If the result is a constant that overflows, raise constraint error. */
3900 {
3903 gnu_result
3906 }
3908 /* If our result has side-effects and is of an unconstrained type,
3909 make a SAVE_EXPR so that we can be sure it will only be referenced
3910 once. Note we must do this before any conversions. */
3917 /* Now convert the result to the proper type. If the type is void or if
3918 we have no result, return error_mark_node to show we have no result.
3919 If the type of the result is correct or if we have a label (which doesn't
3920 have any well-defined type), return our result. Also don't do the
3921 conversion if the "desired" type involves a PLACEHOLDER_EXPR in its size
3922 since those are the cases where the front end may have the type wrong due
3923 to "instantiating" the unconstrained record with discriminant values
3924 or if this is a FIELD_DECL. If this is the Name of an assignment
3925 statement or a parameter of a procedure call, return what we have since
3926 the RHS has to be converted to our type there in that case, unless
3927 GNU_RESULT_TYPE has a simpler size. Similarly, if the two types are
3928 record types with the same name, the expression type has integral mode,
3929 and GNU_RESULT_TYPE BLKmode, don't convert. This will be the case when
3930 we are converting from a packable type to its actual type and we need
3931 those conversions to be NOPs in order for assignments into these types to
3932 work properly if the inner object is a bitfield and hence can't have
3933 its address taken. Finally, don't convert integral types that are the
3934 operand of an unchecked conversion since we need to ignore those
3935 conversions (for 'Valid). Otherwise, convert the result to the proper
3936 type. */
3958 && (contains_placeholder_p
3962 {
3963 /* In this case remove padding only if the inner object is of
3964 self-referential size: in that case it must be an object of
3965 unconstrained type with a default discriminant. In other cases,
3966 we want to avoid copying too much data. */
3973 gnu_result);
3974 }
3990 {
3991 /* Remove any padding record, but do nothing more in this case. */
3995 gnu_result);
3996 }
4004 /* We don't need any NOP_EXPR or NON_LVALUE_EXPR on GNU_RESULT. */
4011 }
4012 \f
4013 /* Force references to each of the entities in packages GNAT_NODE with's
4014 so that the debugging information for all of them are identical
4015 in all clients. Operate recursively on anything it with's, but check
4016 that we aren't elaborating something more than once. */
4018 /* The reason for this routine's existence is two-fold.
4019 First, with some debugging formats, notably MDEBUG on SGI
4020 IRIX, the linker will remove duplicate debugging information if two
4021 clients have identical debugguing information. With the normal scheme
4022 of elaboration, this does not usually occur, since entities in with'ed
4023 packages are elaborated on demand, and if clients have different usage
4024 patterns, the normal case, then the order and selection of entities
4025 will differ. In most cases however, it seems that linkers do not know
4026 how to eliminate duplicate debugging information, even if it is
4027 identical, so the use of this routine would increase the total amount
4028 of debugging information in the final executable.
4030 Second, this routine is called in type_annotate mode, to compute DDA
4031 information for types in withed units, for ASIS use */
4033 static void
4035 Node_Id gnat_node;
4036 {
4041 /* Save entities in all context units. A body may have an implicit_with
4042 on its own spec, if the context includes a child unit, so don't save
4043 the spec twice. */
4051 {
4071 }
4075 }
4076 \f
4077 /* Do the processing of N_Freeze_Entity, GNAT_NODE. */
4079 static void
4081 Node_Id gnat_node;
4082 {
4084 tree gnu_old;
4085 tree gnu_new;
4086 tree gnu_init
4091 /* If this is a package, need to generate code for the package. */
4093 {
4094 insert_code_for
4098 }
4100 /* Check for old definition after the above call. This Freeze_Node
4101 might be for one its Itypes. */
4102 gnu_old
4105 /* If this entity has an Address representation clause, GNU_OLD is the
4106 address, so discard it here. */
4110 /* Don't do anything for class-wide types they are always
4111 transformed into their root type. */
4117 /* Don't do anything for subprograms that may have been elaborated before
4118 their freeze nodes. This can happen, for example because of an inner call
4119 in an instance body. */
4126 /* If we have a non-dummy type old tree, we have nothing to do. Unless
4127 this is the public view of a private type whose full view was not
4128 delayed, this node was never delayed as it should have been.
4129 Also allow this to happen for concurrent types since we may have
4130 frozen both the Corresponding_Record_Type and this type. */
4134 {
4141 else
4143 }
4145 /* Reset the saved tree, if any, and elaborate the object or type for real.
4146 If there is a full declaration, elaborate it and copy the type to
4147 GNAT_ENTITY. Likewise if this is the record subtype corresponding to
4148 a class wide type or subtype. */
4150 {
4159 }
4163 {
4166 /* The above call may have defined this entity (the simplest example
4167 of this is when we have a private enumeral type since the bounds
4168 will have the public view. */
4174 }
4175 else
4178 /* If we've made any pointers to the old version of this type, we
4179 have to update them. */
4183 }
4184 \f
4185 /* Process the list of inlined subprograms of GNAT_NODE, which is an
4186 N_Compilation_Unit. */
4188 static void
4190 Node_Id gnat_node;
4191 {
4192 Entity_Id gnat_entity;
4193 Node_Id gnat_body;
4195 /* If we can inline, generate RTL for all the inlined subprograms.
4196 Define the entity first so we set DECL_EXTERNAL. */
4201 {
4205 {
4206 /* ??? This really should always be Present. */
4210 gnat_body
4212 }
4215 {
4218 }
4219 }
4220 }
4221 \f
4222 /* Elaborate decls in the lists GNAT_DECLS and GNAT_DECLS2, if present.
4223 We make two passes, one to elaborate anything other than bodies (but
4224 we declare a function if there was no spec). The second pass
4225 elaborates the bodies.
4227 GNAT_END_LIST gives the element in the list past the end. Normally,
4228 this is Empty, but can be First_Real_Statement for a
4229 Handled_Sequence_Of_Statements.
4231 We make a complete pass through both lists if PASS1P is true, then make
4232 the second pass over both lists if PASS2P is true. The lists usually
4233 correspond to the public and private parts of a package. */
4235 static void
4238 Node_Id gnat_end_list;
4240 {
4242 Node_Id gnat_decl;
4252 {
4255 /* For package specs, we recurse inside the declarations,
4256 thus taking the two pass approach inside the boundary. */
4264 /* Similarly for any declarations in the actions of a
4265 freeze node. */
4267 {
4270 }
4272 /* Package bodies with freeze nodes get their elaboration deferred
4273 until the freeze node, but the code must be placed in the right
4274 place, so record the code position now. */
4282 (Corresponding_Spec
4285 record_code_position
4288 /* We defer most subprogram bodies to the second pass.
4289 However, Init_Proc subprograms cannot be defered, but luckily
4290 don't need to be. */
4294 {
4296 {
4302 }
4303 }
4304 /* For bodies and stubs that act as their own specs, the entity
4305 itself must be elaborated in the first pass, because it may
4306 be used in other declarations. */
4308 {
4309 Node_Id gnat_subprog_id =
4316 }
4318 /* Concurrent stubs stand for the corresponding subprogram bodies,
4319 which are deferred like other bodies. */
4322 ;
4324 else
4326 }
4328 /* Here we elaborate everything we deferred above except for package bodies,
4329 which are elaborated at their freeze nodes. Note that we must also
4330 go inside things (package specs and freeze nodes) the first pass did. */
4336 {
4354 }
4355 }
4356 \f
4357 /* Emits an access check. GNU_EXPR is the expression that needs to be
4358 checked against the NULL pointer. */
4360 static tree
4362 tree gnu_expr;
4363 {
4364 tree gnu_check_expr;
4366 /* Checked expressions must be evaluated only once. */
4369 /* Technically, we check a fat pointer against two words of zero. However,
4370 that's wasteful and really doesn't protect against null accesses. It
4371 makes more sense to check oly the array pointer. */
4373 gnu_check_expr
4380 gnu_check_expr,
4382 integer_zero_node)),
4383 gnu_expr,
4384 CE_Access_Check_Failed);
4385 }
4387 /* Emits a discriminant check. GNU_EXPR is the expression to be checked and
4388 GNAT_NODE a N_Selected_Component node. */
4390 static tree
4392 tree gnu_expr;
4393 Node_Id gnat_node;
4394 {
4395 Entity_Id orig_comp
4398 tree gnu_discr_fct;
4399 Entity_Id gnat_discr;
4401 tree gnu_cond;
4402 Entity_Id gnat_pref_type;
4403 tree gnu_pref_type;
4407 else
4408 {
4411 /* For an untagged derived type, use the discriminants of the parent,
4412 which have been renamed in the derivation, possibly by a one-to-many
4413 constraint. */
4418 }
4425 /* Checked expressions must be evaluated only once. */
4428 /* Create the list of the actual parameters as GCC expects it.
4429 This list is the list of the discriminant fields of the
4430 record expression to be discriminant checked. For documentation
4431 on what is the GCC format for this list see under the
4432 N_Function_Call case */
4436 {
4441 }
4443 gnu_pref_type
4448 {
4449 Entity_Id gnat_real_discr
4455 gnu_actual_list
4458 build_component_ref
4461 }
4466 gnu_actual_list,
4467 NULL_TREE);
4470 return
4471 build_unary_op
4476 gnu_expr),
4477 CE_Discriminant_Check_Failed));
4478 }
4479 \f
4480 /* Emit code for a range check. GNU_EXPR is the expression to be checked,
4481 GNAT_RANGE_TYPE the gnat type or subtype containing the bounds against
4482 which we have to check. */
4484 static tree
4486 tree gnu_expr;
4487 Entity_Id gnat_range_type;
4488 {
4494 /* If GNU_EXPR has an integral type that is narrower than GNU_RANGE_TYPE,
4495 we can't do anything since we might be truncating the bounds. No
4496 check is needed in this case. */
4502 /* Checked expressions must be evaluated only once. */
4505 /* There's no good type to use here, so we might as well use
4506 integer_type_node. Note that the form of the check is
4507 (not (expr >= lo)) or (not (expr >= hi))
4508 the reason for this slightly convoluted form is that NaN's
4509 are not considered to be in range in the float case. */
4510 return emit_check
4512 invert_truthvalue
4516 invert_truthvalue
4520 gnu_high)))),
4522 }
4523 \f
4524 /* Emit code for an index check. GNU_ARRAY_OBJECT is the array object
4525 which we are about to index, GNU_EXPR is the index expression to be
4526 checked, GNU_LOW and GNU_HIGH are the lower and upper bounds
4527 against which GNU_EXPR has to be checked. Note that for index
4528 checking we cannot use the emit_range_check function (although very
4529 similar code needs to be generated in both cases) since for index
4530 checking the array type against which we are checking the indeces
4531 may be unconstrained and consequently we need to retrieve the
4532 actual index bounds from the array object itself
4533 (GNU_ARRAY_OBJECT). The place where we need to do that is in
4534 subprograms having unconstrained array formal parameters */
4536 static tree
4538 tree gnu_array_object;
4539 tree gnu_expr;
4540 tree gnu_low;
4541 tree gnu_high;
4542 {
4543 tree gnu_expr_check;
4545 /* Checked expressions must be evaluated only once. */
4548 /* Must do this computation in the base type in case the expression's
4549 type is an unsigned subtypes. */
4552 /* If GNU_LOW or GNU_HIGH are a PLACEHOLDER_EXPR, qualify them by
4553 the object we are handling. */
4562 /* There's no good type to use here, so we might as well use
4563 integer_type_node. */
4564 return emit_check
4567 gnu_expr_check,
4569 gnu_low)),
4571 gnu_expr_check,
4573 gnu_high))),
4575 }
4576 \f
4577 /* Given GNU_COND which contains the condition corresponding to an access,
4578 discriminant or range check, of value GNU_EXPR, build a COND_EXPR
4579 that returns GNU_EXPR if GNU_COND is false and raises a
4580 CONSTRAINT_ERROR if GNU_COND is true. REASON is the code that says
4581 why the exception was raised. */
4583 static tree
4585 tree gnu_cond;
4586 tree gnu_expr;
4588 {
4589 tree gnu_call;
4590 tree gnu_result;
4594 /* Use an outer COMPOUND_EXPR to make sure that GNU_EXPR will get evaluated
4595 in front of the comparison in case it ends up being a SAVE_EXPR. Put the
4596 whole thing inside its own SAVE_EXPR so the inner SAVE_EXPR doesn't leak
4597 out. */
4601 gnu_expr));
4603 /* If GNU_EXPR has side effects, make the outer COMPOUND_EXPR and
4604 protect it. Otherwise, show GNU_RESULT has no side effects: we
4605 don't need to evaluate it just for the check. */
4607 gnu_result
4609 else
4612 /* ??? Unfortunately, if we don't put a SAVE_EXPR around this whole thing,
4613 we will repeatedly do the test. It would be nice if GCC was able
4614 to optimize this and only do it once. */
4616 }
4617 \f
4618 /* Return an expression that converts GNU_EXPR to GNAT_TYPE, doing
4619 overflow checks if OVERFLOW_P is nonzero and range checks if
4620 RANGE_P is nonzero. GNAT_TYPE is known to be an integral type.
4621 If TRUNCATE_P is nonzero, do a float to integer conversion with
4622 truncation; otherwise round. */
4624 static tree
4626 Entity_Id gnat_type;
4627 tree gnu_expr;
4631 {
4643 /* If we are not doing any checks, the output is an integral type, and
4644 the input is not a floating type, just do the conversion. This
4645 shortcut is required to avoid problems with packed array types
4646 and simplifies code in all cases anyway. */
4651 /* First convert the expression to its base type. This
4652 will never generate code, but makes the tests below much simpler.
4653 But don't do this if converting from an integer type to an unconstrained
4654 array type since then we need to get the bounds from the original
4655 (unpacked) type. */
4659 /* If overflow checks are requested, we need to be sure the result will
4660 fit in the output base type. But don't do this if the input
4661 is integer and the output floating-point. */
4664 {
4665 /* Ensure GNU_EXPR only gets evaluated once. */
4669 /* Convert the lower bounds to signed types, so we're sure we're
4670 comparing them properly. Likewise, convert the upper bounds
4671 to unsigned types. */
4685 /* Check each bound separately and only if the result bound
4686 is tighter than the bound on the input type. Note that all the
4687 types are base types, so the bounds must be constant. Also,
4688 the comparison is done in the base type of the input, which
4689 always has the proper signedness. First check for input
4690 integer (which means output integer), output float (which means
4691 both float), or mixed, in which case we always compare.
4692 Note that we have to do the comparison which would *fail* in the
4693 case of an error since if it's an FP comparison and one of the
4694 values is a NaN or Inf, the comparison will fail. */
4701 gnu_cond
4702 = invert_truthvalue
4705 gnu_out_lb)));
4713 gnu_cond
4715 invert_truthvalue
4717 gnu_input,
4719 gnu_out_ub))));
4723 CE_Overflow_Check_Failed);
4724 }
4726 /* Now convert to the result base type. If this is a non-truncating
4727 float-to-integer conversion, round. */
4730 {
4740 gnu_result
4742 }
4748 else
4751 /* Finally, do the range check if requested. Note that if the
4752 result type is a modular type, the range check is actually
4753 an overflow check. */
4761 }
4762 \f
4763 /* Return 1 if GNU_EXPR can be directly addressed. This is the case
4764 unless it is an expression involving computation or if it involves
4765 a bitfield reference. This returns the same as
4766 gnat_mark_addressable in most cases. */
4768 static int
4770 tree gnu_expr;
4771 {
4773 {
4798 {
4799 /* This is addressable if we can avoid a copy. */
4813 }
4817 }
4818 }
4819 \f
4820 /* Do the processing for the declaration of a GNAT_ENTITY, a type. If
4821 a separate Freeze node exists, delay the bulk of the processing. Otherwise
4822 make a GCC type for GNAT_ENTITY and set up the correspondance. */
4824 void
4826 Entity_Id gnat_entity;
4827 {
4828 tree gnu_old
4830 tree gnu_new;
4832 /* If we are to delay elaboration of this type, just do any
4833 elaborations needed for expressions within the declaration and
4834 make a dummy type entry for this node and its Full_View (if
4835 any) in case something points to it. Don't do this if it
4836 has already been done (the only way that can happen is if
4837 the private completion is also delayed). */
4843 {
4847 {
4856 }
4859 }
4861 /* If we saved away a dummy type for this node it means that this
4862 made the type that corresponds to the full type of an incomplete
4863 type. Clear that type for now and then update the type in the
4864 pointers. */
4866 {
4869 {
4870 /* If this was a withed access type, this is not an error
4871 and merely indicates we've already elaborated the type
4872 already. */
4877 }
4880 }
4882 /* Now fully elaborate the type. */
4887 /* If we have an old type and we've made pointers to this type,
4888 update those pointers. */
4893 /* If this is a record type corresponding to a task or protected type
4894 that is a completion of an incomplete type, perform a similar update
4895 on the type. */
4896 /* ??? Including protected types here is a guess. */
4901 {
4902 tree gnu_task_old
4912 }
4913 }
4914 \f
4915 /* GNAT_ASSOC is the front of the Component_Associations of an N_Aggregate.
4916 GNU_TYPE is the GCC type of the corresponding record.
4918 Return a CONSTRUCTOR to build the record. */
4920 static tree
4922 Node_Id gnat_assoc;
4923 tree gnu_type;
4924 {
4927 /* We test for GNU_FIELD being empty in the case where a variant
4928 was the last thing since we don't take things off GNAT_ASSOC in
4929 that case. We check GNAT_ASSOC in case we have a variant, but it
4930 has no fields. */
4934 {
4939 /* The expander is supposed to put a single component selector name
4940 in every record component association */
4944 /* Before assigning a value in an aggregate make sure range checks
4945 are done if required. Then convert to the type of the field. */
4951 /* Add the field and expression to the list. */
4953 }
4957 /* Verify every enty in GNU_LIST was used. */
4963 }
4965 /* Builds a possibly nested constructor for array aggregates. GNAT_EXPR
4966 is the first element of an array aggregate. It may itself be an
4967 aggregate (an array or record aggregate). GNU_ARRAY_TYPE is the gnu type
4968 corresponding to the array aggregate. GNAT_COMPONENT_TYPE is the type
4969 of the array component. It is needed for range checking. */
4971 static tree
4973 Node_Id gnat_expr;
4974 tree gnu_array_type;
4975 Entity_Id gnat_component_type;
4976 {
4977 tree gnu_expr;
4981 {
4982 /* If the expression is itself an array aggregate then first build the
4983 innermost constructor if it is part of our array (multi-dimensional
4984 case). */
4991 gnat_component_type);
4992 else
4993 {
4996 /* before assigning the element to the array make sure it is
4997 in range */
5000 }
5002 gnu_expr_list
5004 gnu_expr_list);
5005 }
5008 }
5009 \f
5010 /* Subroutine of assoc_to_constructor: VALUES is a list of field associations,
5011 some of which are from RECORD_TYPE. Return a CONSTRUCTOR consisting
5012 of the associations that are from RECORD_TYPE. If we see an internal
5013 record, make a recursive call to fill it in as well. */
5015 static tree
5017 tree values;
5018 tree record_type;
5019 {
5024 {
5027 /* _Parent is an internal field, but may have values in the aggregate,
5028 so check for values first. */
5030 {
5033 }
5036 {
5041 }
5042 else
5043 /* If we have a record subtype, the names will match, but not the
5044 actual FIELD_DECLs. */
5047 {
5050 }
5056 }
5059 }
5060 \f
5061 /* EXP is to be treated as an array or record. Handle the cases when it is
5062 an access object and perform the required dereferences. */
5064 static tree
5066 tree exp;
5067 {
5068 /* If the type is a pointer, dereference it. */
5073 /* If we got a padded type, remove it too. */
5079 }
5080 \f
5081 /* Protect EXP from multiple evaluation. This may make a SAVE_EXPR. */
5083 tree
5085 tree exp;
5086 {
5089 /* If this has no side effects, we don't need to do anything. */
5093 /* If it is a conversion, protect what's inside the conversion.
5094 Similarly, if we're indirectly referencing something, we only
5095 actually need to protect the address since the data itself can't
5096 change in these situations. */
5105 /* If EXP is a fat pointer or something that can be placed into a register,
5106 just make a SAVE_EXPR. */
5110 /* Otherwise, dereference, protect the address, and re-reference. */
5111 else
5112 return
5116 exp)));
5117 }
5118 \f
5119 /* This is equivalent to stabilize_reference in GCC's tree.c, but we know
5120 how to handle our new nodes and we take an extra argument that says
5121 whether to force evaluation of everything. */
5123 tree
5125 tree ref;
5127 {
5133 {
5137 /* No action is needed in this case. */
5149 result
5158 force));
5164 force),
5172 force),
5174 force));
5181 force));
5188 force));
5194 force),
5196 force));
5205 /* If arg isn't a kind of lvalue we recognize, make no change.
5206 Caller should recognize the error for an invalid lvalue. */
5212 }
5216 }
5218 /* Similar to stabilize_reference_1 in tree.c, but supports an extra
5219 arg to force a SAVE_EXPR for everything. */
5221 static tree
5223 tree e;
5225 {
5230 /* We cannot ignore const expressions because it might be a reference
5231 to a const array but whose index contains side-effects. But we can
5232 ignore things that are actual constant or that already have been
5233 handled by this function. */
5239 {
5253 /* Constants need no processing. In fact, we should never reach
5254 here. */
5258 /* Recursively stabilize each operand. */
5265 /* Recursively stabilize each operand. */
5268 force));
5273 }
5277 }
5278 \f
5279 /* GNAT_UNIT is the Defining_Identifier for some package or subprogram,
5280 either a spec or a body, BODY_P says which. If needed, make a function
5281 to be the elaboration routine for that object and perform the elaborations
5282 in GNU_ELAB_LIST.
5284 Return 1 if we didn't need an elaboration function, zero otherwise. */
5286 static int
5288 Entity_Id gnat_unit;
5290 tree gnu_elab_list;
5291 {
5292 tree gnu_decl;
5293 rtx insn;
5296 /* If we have nothing to do, return. */
5300 /* Prevent the elaboration list from being reclaimed by the GC. */
5302 gnu_elab_list);
5304 /* Set our file and line number to that of the object and set up the
5305 elaboration routine. */
5307 body_p ?
5319 /* Emit the assignments for the elaborations we have to do. If there
5320 is no destination, this is just a call to execute some statement
5321 that was placed within the declarative region. But first save a
5322 pointer so we can see if any insns were generated. */
5328 {
5331 }
5332 else
5333 {
5338 /* If LHS has a padded type, convert it to the unpadded type
5339 so the assignment is done properly. */
5348 }
5350 /* See if any non-NOTE insns were generated. */
5353 {
5356 }
5363 /* We are finished with the elaboration list it can now be discarded. */
5366 /* If there were no insns, we don't need an elab routine. It would
5367 be nice to not output this one, but there's no good way to do that. */
5369 }
5370 \f
5373 /* Determine the input_filename and the input_line from the source location
5374 (Sloc) of GNAT_NODE node. Set the global variable input_filename and
5375 input_line. If WRITE_NOTE_P is true, emit a line number note. */
5377 void
5379 Node_Id gnat_node;
5381 {
5384 /* If node not from source code, ignore. */
5388 /* Use the identifier table to make a hashed, permanent copy of the filename,
5389 since the name table gets reallocated after Gigi returns but before all
5390 the debugging information is output. The call to
5391 __gnat_to_canonical_file_spec translates filenames from pragmas
5392 Source_Reference that contain host style syntax not understood by gdb. */
5393 input_filename
5394 = IDENTIFIER_POINTER
5395 (get_identifier
5396 (__gnat_to_canonical_file_spec
5397 (Get_Name_String
5400 /* ref_filename is the reference file name as given by sinput (i.e no
5401 directory) */
5402 ref_filename
5403 = IDENTIFIER_POINTER
5404 (get_identifier
5405 (Get_Name_String
5411 }
5412 \f
5413 /* Post an error message. MSG is the error message, properly annotated.
5414 NODE is the node at which to post the error and the node to use for the
5415 "&" substitution. */
5417 void
5420 Node_Id node;
5421 {
5422 String_Template temp;
5423 Fat_Pointer fp;
5429 }
5431 /* Similar, but NODE is the node at which to post the error and ENT
5432 is the node to use for the "&" substitution. */
5434 void
5437 Node_Id node;
5438 Entity_Id ent;
5439 {
5440 String_Template temp;
5441 Fat_Pointer fp;
5447 }
5449 /* Similar, but NODE is the node at which to post the error, ENT is the node
5450 to use for the "&" substitution, and N is the number to use for the ^. */
5452 void
5455 Node_Id node;
5456 Entity_Id ent;
5458 {
5459 String_Template temp;
5460 Fat_Pointer fp;
5468 }
5469 \f
5470 /* Similar to post_error_ne_num, but T is a GCC tree representing the
5471 number to write. If the tree represents a constant that fits within
5472 a host integer, the text inside curly brackets in MSG will be output
5473 (presumably including a '^'). Otherwise that text will not be output
5474 and the text inside square brackets will be output instead. */
5476 void
5479 Node_Id node;
5480 Entity_Id ent;
5481 tree t;
5482 {
5485 Fat_Pointer fp;
5493 #if HOST_BITS_PER_WIDE_INT > HOST_BITS_PER_INT
5495 #endif
5496 )
5497 {
5500 }
5501 else
5505 {
5511 ;
5512 else
5514 }
5521 }
5523 /* Similar to post_error_ne_tree, except that NUM is a second
5524 integer to write in the message. */
5526 void
5529 Node_Id node;
5530 Entity_Id ent;
5531 tree t;
5533 {
5536 }
5538 /* Set the node for a second '&' in the error message. */
5540 void
5542 Entity_Id e;
5543 {
5545 }
5546 \f
5547 /* Signal abort, with "Gigi abort" as the error label, and error_gnat_node
5548 as the relevant node that provides the location info for the error */
5550 void
5553 {
5555 Fat_Pointer fp;
5561 }
5562 \f
5563 /* Initialize the table that maps GNAT codes to GCC codes for simple
5564 binary and unary operations. */
5566 void
5568 {
5594 }