| blob | a12b84744c0897b27d4da108c8479acbedb73e3e |
1 /* Convert function calls to rtl insns, for GNU C compiler.
2 Copyright (C) 1989-2020 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
9 version.
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
20 #define INCLUDE_STRING
66 /* Like PREFERRED_STACK_BOUNDARY but in units of bytes, not bits. */
67 #define STACK_BYTES (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT)
69 /* Data structure and subroutines used within expand_call. */
71 struct arg_data
72 {
73 /* Tree node for this argument. */
74 tree tree_value;
75 /* Mode for value; TYPE_MODE unless promoted. */
76 machine_mode mode;
77 /* Current RTL value for argument, or 0 if it isn't precomputed. */
78 rtx value;
79 /* Initially-compute RTL value for argument; only for const functions. */
80 rtx initial_value;
81 /* Register to pass this argument in, 0 if passed on stack, or an
82 PARALLEL if the arg is to be copied into multiple non-contiguous
83 registers. */
84 rtx reg;
85 /* Register to pass this argument in when generating tail call sequence.
86 This is not the same register as for normal calls on machines with
87 register windows. */
88 rtx tail_call_reg;
89 /* If REG is a PARALLEL, this is a copy of VALUE pulled into the correct
90 form for emit_group_move. */
91 rtx parallel_value;
92 /* If REG was promoted from the actual mode of the argument expression,
93 indicates whether the promotion is sign- or zero-extended. */
95 /* Number of bytes to put in registers. 0 means put the whole arg
96 in registers. Also 0 if not passed in registers. */
98 /* Nonzero if argument must be passed on stack.
99 Note that some arguments may be passed on the stack
100 even though pass_on_stack is zero, just because FUNCTION_ARG says so.
101 pass_on_stack identifies arguments that *cannot* go in registers. */
103 /* Some fields packaged up for locate_and_pad_parm. */
105 /* Location on the stack at which parameter should be stored. The store
106 has already been done if STACK == VALUE. */
107 rtx stack;
108 /* Location on the stack of the start of this argument slot. This can
109 differ from STACK if this arg pads downward. This location is known
110 to be aligned to TARGET_FUNCTION_ARG_BOUNDARY. */
111 rtx stack_slot;
112 /* Place that this stack area has been saved, if needed. */
113 rtx save_area;
114 /* If an argument's alignment does not permit direct copying into registers,
115 copy in smaller-sized pieces into pseudos. These are stored in a
116 block pointed to by this field. The next field says how many
117 word-sized pseudos we made. */
120 };
122 /* A vector of one char per byte of stack space. A byte if nonzero if
123 the corresponding stack location has been used.
124 This vector is used to prevent a function call within an argument from
125 clobbering any stack already set up. */
128 /* Size of STACK_USAGE_MAP. */
131 /* Assume that any stack location at this byte index is used,
132 without checking the contents of stack_usage_map. */
135 /* A bitmap of virtual-incoming stack space. Bit is set if the corresponding
136 stack location's tail call argument has been already stored into the stack.
137 This bitmap is used to prevent sibling call optimization if function tries
138 to use parent's incoming argument slots when they have been already
139 overwritten with tail call arguments. */
142 /* Assume that any virtual-incoming location at this byte index has been
143 stored, without checking the contents of stored_args_map. */
146 /* stack_arg_under_construction is nonzero when an argument may be
147 initialized with a constructor call (including a C function that
148 returns a BLKmode struct) and expand_call must take special action
149 to make sure the object being constructed does not overlap the
150 argument list for the constructor call. */
169 #ifdef REG_PARM_STACK_SPACE
172 #endif
173 \f
174 /* Return true if bytes [LOWER_BOUND, UPPER_BOUND) of the outgoing
175 stack region might already be in use. */
177 static bool
180 {
189 /* Don't worry about things in the fixed argument area;
190 it has already been saved. */
197 }
199 /* Record that bytes [LOWER_BOUND, UPPER_BOUND) of the outgoing
200 stack region are now in use. */
202 static void
204 {
210 else
212 }
214 /* Force FUNEXP into a form suitable for the address of a CALL,
215 and return that as an rtx. Also load the static chain register
216 if FNDECL is a nested function.
218 CALL_FUSAGE points to a variable holding the prospective
219 CALL_INSN_FUNCTION_USAGE information. */
221 rtx
224 {
225 /* Make a valid memory address and copy constants through pseudo-regs,
226 but not for a constant address if -fno-function-cse. */
228 {
229 /* If it's an indirect call by descriptor, generate code to perform
230 runtime identification of the pointer and load the descriptor. */
232 {
237 fndecl_or_type
239 fndecl_or_type);
246 /* Avoid long live ranges around function calls. */
252 /* Emit the runtime identification pattern. */
255 call_lab);
257 /* Statically predict the branch to very likely taken. */
262 /* Load the descriptor. */
271 POINTER_SIZE / BITS_PER_UNIT
280 {
283 }
285 /* Make sure we're not going to be overwritten below. */
287 }
289 /* If we are using registers for parameters, force the
290 function address into a register now. */
291 funexp = ((reg_parm_seen
295 }
296 else
297 {
298 /* funexp could be a SYMBOL_REF represents a function pointer which is
299 of ptr_mode. In this case, it should be converted into address mode
300 to be a valid address for memory rtx pattern. See PR 64971. */
305 {
308 }
309 }
314 {
315 rtx chain;
322 {
325 }
326 }
329 }
331 /* Generate instructions to call function FUNEXP,
332 and optionally pop the results.
333 The CALL_INSN is the first insn generated.
335 FNDECL is the declaration node of the function. This is given to the
336 hook TARGET_RETURN_POPS_ARGS to determine whether this function pops
337 its own args.
339 FUNTYPE is the data type of the function. This is given to the hook
340 TARGET_RETURN_POPS_ARGS to determine whether this function pops its
341 own args. We used to allow an identifier for library functions, but
342 that doesn't work when the return type is an aggregate type and the
343 calling convention says that the pointer to this aggregate is to be
344 popped by the callee.
346 STACK_SIZE is the number of bytes of arguments on the stack,
347 ROUNDED_STACK_SIZE is that number rounded up to
348 PREFERRED_STACK_BOUNDARY; zero if the size is variable. This is
349 both to put into the call insn and to generate explicit popping
350 code if necessary.
352 STRUCT_VALUE_SIZE is the number of bytes wanted in a structure value.
353 It is zero if this call doesn't want a structure value.
355 NEXT_ARG_REG is the rtx that results from executing
356 targetm.calls.function_arg (&args_so_far,
357 function_arg_info::end_marker ());
358 just after all the args have had their registers assigned.
359 This could be whatever you like, but normally it is the first
360 arg-register beyond those used for args in this call,
361 or 0 if all the arg-registers are used in this call.
362 It is passed on to `gen_call' so you can put this info in the call insn.
364 VALREG is a hard register in which a value is returned,
365 or 0 if the call does not return a value.
367 OLD_INHIBIT_DEFER_POP is the value that `inhibit_defer_pop' had before
368 the args to this call were processed.
369 We restore `inhibit_defer_pop' to that value.
371 CALL_FUSAGE is either empty or an EXPR_LIST of USE expressions that
372 denote registers used by the called function. */
374 static void
376 tree funtype ATTRIBUTE_UNUSED,
377 poly_int64 stack_size ATTRIBUTE_UNUSED,
378 poly_int64 rounded_stack_size,
379 poly_int64 struct_value_size ATTRIBUTE_UNUSED,
382 cumulative_args_t args_so_far ATTRIBUTE_UNUSED)
383 {
389 /* Sibling call patterns never pop arguments (no sibcall(_value)_pop
390 patterns exist). Any popping that the callee does on return will
391 be from our caller's frame rather than ours. */
393 {
396 #ifdef CALL_POPS_ARGS
398 #endif
399 }
401 /* Ensure address is valid. SYMBOL_REF is already valid, so no need,
402 and we don't want to load it into a register as an optimization,
403 because prepare_call_address already did it if it should be done. */
409 {
412 /* Although a built-in FUNCTION_DECL and its non-__builtin
413 counterpart compare equal and get a shared mem_attrs, they
414 produce different dump output in compare-debug compilations,
415 if an entry gets garbage collected in one compilation, then
416 adds a different (but equivalent) entry, while the other
417 doesn't run the garbage collector at the same spot and then
418 shares the mem_attr with the equivalent entry. */
420 {
424 }
427 }
432 {
435 rounded_stack_size_rtx,
437 else
439 next_arg_reg,
441 }
442 /* If the target has "call" or "call_value" insns, then prefer them
443 if no arguments are actually popped. If the target does not have
444 "call" or "call_value" insns, then we must use the popping versions
445 even if the call has no arguments to pop. */
447 || !(valreg
450 {
453 /* If this subroutine pops its own args, record that in the call insn
454 if possible, for the sake of frame pointer elimination. */
458 rounded_stack_size_rtx,
460 else
465 }
466 else
467 {
471 else
474 }
477 /* Find the call we just emitted. */
480 /* Some target create a fresh MEM instead of reusing the one provided
481 above. Set its MEM_EXPR. */
488 /* Put the register usage information there. */
491 /* If this is a const call, then set the insn's unchanging bit. */
495 /* If this is a pure call, then set the insn's unchanging bit. */
499 /* If this is a const call, then set the insn's unchanging bit. */
503 /* Create a nothrow REG_EH_REGION note, if needed. */
510 {
513 }
517 /* Restore this now, so that we do defer pops for this call's args
518 if the context of the call as a whole permits. */
522 {
534 /* If popup is needed, stack realign must use DRAP */
537 }
538 /* For noreturn calls when not accumulating outgoing args force
539 REG_ARGS_SIZE note to prevent crossjumping of calls with different
540 args sizes. */
545 {
546 /* If returning from the subroutine does not automatically pop the args,
547 we need an instruction to pop them sooner or later.
548 Perhaps do it now; perhaps just record how much space to pop later.
550 If returning from the subroutine does pop the args, indicate that the
551 stack pointer will be changed. */
554 {
556 /* Just pretend we did the pop. */
561 else
563 }
564 }
565 /* When we accumulate outgoing args, we must avoid any stack manipulations.
566 Restore the stack pointer to its original value now. Usually
567 ACCUMULATE_OUTGOING_ARGS targets don't get here, but there are exceptions.
568 On i386 ACCUMULATE_OUTGOING_ARGS can be enabled on demand, and
569 popping variants of functions exist as well.
571 ??? We may optimize similar to defer_pop above, but it is
572 probably not worthwhile.
574 ??? It will be worthwhile to enable combine_stack_adjustments even for
575 such machines. */
578 }
580 /* Determine if the function identified by FNDECL is one with
581 special properties we wish to know about. Modify FLAGS accordingly.
583 For example, if the function might return more than one time (setjmp), then
584 set ECF_RETURNS_TWICE.
586 Set ECF_MAY_BE_ALLOCA for any memory allocation function that might allocate
587 space from the stack such as alloca. */
589 static int
591 {
596 {
600 /* We assume that alloca will always be called by name. It
601 makes no sense to pass it as a pointer-to-function to
602 anything that does not understand its behavior. */
608 /* Disregard prefix _ or __. */
610 {
613 else
615 }
617 /* ECF_RETURNS_TWICE is safe even for -ffreestanding. */
624 }
631 }
633 /* Similar to special_function_p; return a set of ERF_ flags for the
634 function FNDECL. */
635 static int
637 {
638 tree attr;
656 }
658 /* Return nonzero when FNDECL represents a call to setjmp. */
660 int
662 {
666 }
669 /* Return true if STMT may be an alloca call. */
671 bool
673 {
674 tree fndecl;
684 }
686 /* Return true if STMT is a builtin alloca call. */
688 bool
690 {
691 tree fndecl;
699 {
700 CASE_BUILT_IN_ALLOCA:
704 }
707 }
709 /* Return true when exp contains a builtin alloca call. */
711 bool
713 {
714 tree fndecl;
719 {
720 CASE_BUILT_IN_ALLOCA:
724 }
727 }
729 /* Return TRUE if FNDECL is either a TM builtin or a TM cloned
730 function. Return FALSE otherwise. */
732 static bool
734 {
742 {
744 {
787 }
788 }
790 }
792 /* Detect flags (function attributes) from the function decl or type node. */
794 int
796 {
800 {
801 /* The function exp may have the `malloc' attribute. */
805 /* The function exp may have the `returns_twice' attribute. */
809 /* Process the pure and const attributes. */
828 {
835 }
838 }
840 {
848 }
849 else
853 {
857 }
860 }
862 /* Detect flags from a CALL_EXPR. */
864 int
866 {
874 else
875 {
879 else
883 }
886 }
888 /* Return true if ARG should be passed by invisible reference. */
890 bool
892 {
894 {
895 /* If this type contains non-trivial constructors, then it is
896 forbidden for the middle-end to create any new copies. */
900 /* GCC post 3.4 passes *all* variable sized types by reference. */
904 /* If a record type should be passed the same as its first (and only)
905 member, use the type and mode of that member. */
907 {
910 }
911 }
914 }
916 /* Return true if TYPE should be passed by reference when passed to
917 the "..." arguments of a function. */
919 bool
921 {
923 }
925 /* Decide whether ARG, which occurs in the state described by CA,
926 should be passed by reference. Return true if so and update
927 ARG accordingly. */
929 bool
931 {
933 {
938 }
940 }
942 /* Return true if ARG, which is passed by reference, should be callee
943 copied instead of caller copied. */
945 bool
947 {
951 }
954 /* Precompute all register parameters as described by ARGS, storing values
955 into fields within the ARGS array.
957 NUM_ACTUALS indicates the total number elements in the ARGS array.
959 Set REG_PARM_SEEN if we encounter a register parameter. */
961 static void
964 {
971 {
975 {
980 }
982 /* If we are to promote the function arg to a wider mode,
983 do it now. */
991 /* If the value is a non-legitimate constant, force it into a
992 pseudo now. TLS symbols sometimes need a call to resolve. */
997 /* If we're going to have to load the value by parts, pull the
998 parts into pseudos. The part extraction process can involve
999 non-trivial computation. */
1001 {
1006 }
1008 /* If the value is expensive, and we are inside an appropriately
1009 short loop, put the value into a pseudo and then put the pseudo
1010 into the hard reg.
1012 For small register classes, also do this if this call uses
1013 register parameters. This is to avoid reload conflicts while
1014 loading the parameters registers. */
1023 && ((*reg_parm_seen
1027 }
1028 }
1030 #ifdef REG_PARM_STACK_SPACE
1032 /* The argument list is the property of the called routine and it
1033 may clobber it. If the fixed area has been used for previous
1034 parameters, we must save and restore it. */
1036 static rtx
1037 save_fixed_argument_area (int reg_parm_stack_space, rtx argblock, int *low_to_save, int *high_to_save)
1038 {
1042 /* Compute the boundary of the area that needs to be saved, if any. */
1052 {
1054 machine_mode save_mode;
1056 rtx addr;
1057 rtx stack_area;
1058 rtx save_area;
1061 ;
1068 /* If we don't have the required alignment, must do this
1069 in BLKmode. */
1070 scalar_int_mode imode;
1075 else
1080 else
1088 {
1092 }
1093 else
1094 {
1097 }
1100 }
1103 }
1105 static void
1107 {
1114 else
1123 else
1126 BLOCK_OP_CALL_PARM);
1127 }
1130 /* If any elements in ARGS refer to parameters that are to be passed in
1131 registers, but not in memory, and whose alignment does not permit a
1132 direct copy into registers. Copy the values into a group of pseudos
1133 which we will later copy into the appropriate hard registers.
1135 Pseudos for each unaligned argument will be stored into the array
1136 args[argnum].aligned_regs. The caller is responsible for deallocating
1137 the aligned_regs array if it is nonzero. */
1139 static void
1141 {
1151 {
1156 {
1159 }
1160 else
1161 {
1164 }
1168 /* Structures smaller than a word are normally aligned to the
1169 least significant byte. On a BYTES_BIG_ENDIAN machine,
1170 this means we must skip the empty high order bytes when
1171 calculating the bit offset. */
1173 #ifdef BLOCK_REG_PADDING
1177 #else
1178 && BYTES_BIG_ENDIAN
1179 #endif
1180 )
1184 {
1193 /* There is no need to restrict this code to loading items
1194 in TYPE_ALIGN sized hunks. The bitfield instructions can
1195 load up entire word sized registers efficiently.
1197 ??? This may not be needed anymore.
1198 We use to emit a clobber here but that doesn't let later
1199 passes optimize the instructions we emit. By storing 0 into
1200 the register later passes know the first AND to zero out the
1201 bitfield being set in the register is unnecessary. The store
1202 of 0 will be deleted as will at least the first AND. */
1209 }
1210 }
1211 }
1213 /* The limit set by -Walloc-larger-than=. */
1216 /* Initialize ALLOC_OBJECT_SIZE_LIMIT based on the -Walloc-size-larger-than=
1217 setting if the option is specified, or to the maximum object size if it
1218 is not. Return the initialized value. */
1220 static tree
1222 {
1233 }
1235 /* Return true when EXP's range can be determined and set RANGE[] to it
1236 after adjusting it if necessary to make EXP a represents a valid size
1237 of object, or a valid size argument to an allocation function declared
1238 with attribute alloc_size (whose argument may be signed), or to a string
1239 manipulation function like memset.
1240 When ALLOW_ZERO is set in FLAGS, allow returning a range of [0, 0] for
1241 a size in an anti-range [1, N] where N > PTRDIFF_MAX. A zero range is
1242 a (nearly) invalid argument to allocation functions like malloc but it
1243 is a valid argument to functions like memset.
1244 When USE_LARGEST is set in FLAGS set RANGE to the largest valid subrange
1245 in a multi-range, otherwise to the smallest valid subrange. */
1247 bool
1250 {
1255 {
1256 /* EXP is a constant. */
1259 }
1268 {
1269 value_range vr;
1271 {
1274 {
1277 }
1278 }
1279 else
1282 }
1283 else
1287 {
1289 {
1290 /* Use the full range of the type of the expression when
1291 no value range information is available. */
1295 }
1300 }
1307 {
1309 {
1311 {
1312 /* EXP is not in a strictly negative range. That means
1313 it must be in some (not necessarily strictly) positive
1314 range which includes zero. Since in signed to unsigned
1315 conversions negative values end up converted to large
1316 positive values, and otherwise they are not valid sizes,
1317 the resulting range is in both cases [0, TYPE_MAX]. */
1320 }
1322 {
1323 /* EXP is not in a negative-positive range. That means EXP
1324 is either negative, or greater than max. Since negative
1325 sizes are invalid make the range [MAX + 1, TYPE_MAX]. */
1328 }
1329 else
1330 {
1333 }
1334 }
1335 else
1336 {
1341 {
1342 /* EXP is unsigned and not in the range [1, MAX]. That means
1343 it's either zero or greater than MAX. Even though 0 would
1344 normally be detected by -Walloc-zero, unless ALLOW_ZERO
1345 is set, set the range to [MAX, TYPE_MAX] so that when MAX
1346 is greater than the limit the whole range is diagnosed. */
1349 {
1353 else
1354 {
1357 }
1358 }
1359 else
1360 {
1363 }
1364 }
1367 {
1368 /* When USE_LARGEST is set and the larger of the two subranges
1369 is a valid size, use it... */
1372 }
1373 else
1374 {
1375 /* ...otherwise use the smaller subrange. */
1378 }
1379 }
1380 }
1386 }
1388 bool
1390 {
1392 }
1394 /* Diagnose a call EXP to function FN decorated with attribute alloc_size
1395 whose argument numbers given by IDX with values given by ARGS exceed
1396 the maximum object size or cause an unsigned oveflow (wrapping) when
1397 multiplied. FN is null when EXP is a call via a function pointer.
1398 When ARGS[0] is null the function does nothing. ARGS[1] may be null
1399 for functions like malloc, and non-null for those like calloc that
1400 are decorated with a two-argument attribute alloc_size. */
1402 void
1404 {
1405 /* The range each of the (up to) two arguments is known to be in. */
1408 /* Maximum object size set by -Walloc-size-larger-than= or SIZE_MAX / 2. */
1416 /* Validate each argument individually. */
1418 {
1420 {
1425 {
1429 }
1431 {
1432 /* Avoid issuing -Walloc-zero for allocation functions other
1433 than __builtin_alloca that are declared with attribute
1434 returns_nonnull because there's no portability risk. This
1435 avoids warning for such calls to libiberty's xmalloc and
1436 friends.
1437 Also avoid issuing the warning for calls to function named
1438 "alloca". */
1446 }
1448 {
1449 /* G++ emits calls to ::operator new[](SIZE_MAX) in C++98
1450 mode and with -fno-exceptions as a way to indicate array
1451 size overflow. There's no good way to detect C++98 here
1452 so avoid diagnosing these calls for all C++ modes. */
1454 && fn
1462 "%Kargument %i value %qE exceeds "
1465 }
1466 }
1469 {
1470 /* Verify that the argument's range is not negative (including
1471 upper bound of zero). */
1474 {
1479 }
1481 {
1483 "%Kargument %i range [%E, %E] exceeds "
1487 maxobjsize);
1488 }
1489 }
1490 }
1495 /* For a two-argument alloc_size, validate the product of the two
1496 arguments if both of their values or ranges are known. */
1501 {
1502 /* Check for overflow in the product of a function decorated with
1503 attribute alloc_size (X, Y). */
1513 "%Kproduct %<%E * %E%> of arguments %i and %i "
1519 "%Kproduct %<%E * %E%> of arguments %i and %i "
1523 maxobjsize);
1526 {
1527 /* Print the full range of each of the two arguments to make
1528 it clear when it is, in fact, in a range and not constant. */
1535 }
1536 }
1539 {
1545 else
1548 }
1549 }
1551 /* If EXPR refers to a character array or pointer declared attribute
1552 nonstring return a decl for that array or pointer and set *REF to
1553 the referenced enclosing object or pointer. Otherwise returns
1554 null. */
1556 tree
1558 {
1562 {
1566 {
1572 }
1573 else
1575 }
1580 /* To simplify calling code, store the referenced DECL regardless of
1581 the attribute determined below, but avoid storing the SSA_NAME_VAR
1582 obtained above (it's not useful for dataflow purposes). */
1586 /* Use the SSA_NAME_VAR that was determined above to see if it's
1587 declared nonstring. Otherwise drill down into the referenced
1588 DECL. */
1603 }
1605 /* Warn about passing a non-string array/pointer to a built-in function
1606 that expects a nul-terminated string argument. Returns true if
1607 a warning has been issued.*/
1609 bool
1611 {
1618 /* Avoid clearly invalid calls (more checking done below). */
1623 /* The bound argument to a bounded string function like strncpy. */
1626 /* The longest known or possible string argument to one of the comparison
1627 functions. If the length is less than the bound it is used instead.
1628 Since the length is only used for warning and not for code generation
1629 disable strict mode in the calls to get_range_strlen below. */
1632 /* It's safe to call "bounded" string functions with a non-string
1633 argument since the functions provide an explicit bound for this
1634 purpose. The exception is strncat where the bound may refer to
1635 either the destination or the source. */
1638 {
1642 {
1643 /* For these, if one argument refers to one or more of a set
1644 of string constants or arrays of known size, determine
1645 the range of their known or possible lengths and use it
1646 conservatively as the bound for the unbounded function,
1647 and to adjust the range of the bound of the bounded ones. */
1651 {
1654 {
1655 c_strlen_data lendata = { };
1656 /* Set MAXBOUND to an arbitrary non-null non-integer
1657 node as a request to have it set to the length of
1658 the longest string in a PHI. */
1662 }
1663 }
1664 }
1665 /* Fall through. */
1680 {
1683 {
1684 c_strlen_data lendata = { };
1685 /* Set MAXBOUND to an arbitrary non-null non-integer
1686 node as a request to have it set to the length of
1687 the longest string in a PHI. */
1691 }
1695 }
1699 }
1701 /* Determine the range of the bound argument (if specified). */
1704 {
1707 }
1712 {
1713 /* Diagnose excessive bound prior to the adjustment below and
1714 regardless of attribute nonstring. */
1717 {
1721 "%K%qD specified bound %E "
1724 else
1726 "%K%qD specified bound [%E, %E] "
1729 maxobjsize);
1734 }
1735 }
1738 {
1739 /* Add one for the nul. */
1741 size_one_node);
1744 {
1745 /* Conservatively use the upper bound of the lengths for
1746 both the lower and the upper bound of the operation. */
1750 }
1752 {
1753 /* Replace the bound on the operation with the upper bound
1754 of the length of the string if the latter is smaller. */
1759 }
1760 }
1763 /* Iterate over the built-in function's formal arguments and check
1764 each const char* against the actual argument. If the actual
1765 argument is declared attribute non-string issue a warning unless
1766 the argument's maximum length is bounded. */
1767 function_args_iterator it;
1771 {
1772 /* Avoid iterating past the declared argument in a call
1773 to function declared without a prototype. */
1798 /* See if the destination is declared with attribute "nonstring". */
1803 /* The maximum number of array elements accessed. */
1807 {
1808 /* See if the bound in strncat is derived from the length
1809 of the strlen of the destination (as it's expected to be).
1810 If so, reset BOUND and FNCODE to trigger a warning. */
1813 {
1814 /* The bound applies to the destination, not to the source,
1815 so reset these to trigger a warning without mentioning
1816 the bound. */
1819 }
1821 /* Use the upper bound of the range for strncat. */
1823 }
1825 /* Use the lower bound of the range for functions other than
1826 strncat. */
1829 /* Determine the size of the argument array if it is one. */
1834 /* Determine the array size. For arrays of unknown bound and
1835 pointers reset BOUND to trigger the appropriate warning. */
1837 {
1839 {
1841 {
1844 }
1845 }
1848 }
1852 /* In a call to strncat with a bound in a range whose lower but
1853 not upper bound is less than the array size, reset ASIZE to
1854 be the same as the bound and the other variable to trigger
1855 the apprpriate warning below. */
1859 && (!known_size
1861 {
1865 }
1869 auto_diagnostic_group d;
1871 {
1874 "%qD argument %i declared attribute "
1875 "%<nonstring%> is smaller than the specified "
1880 "%qD argument %i declared attribute "
1881 "%<nonstring%> is smaller than "
1884 else
1886 "%qD argument %i declared attribute "
1887 "%<nonstring%> may be smaller than "
1890 }
1893 is equal to the size of the non-string argument. */
1900 {
1904 }
1905 }
1911 }
1913 /* Issue an error if CALL_EXPR was flagged as requiring
1914 tall-call optimization. */
1916 static void
1918 {
1924 }
1926 /* Returns the type of the argument ARGNO to function with type FNTYPE
1927 or null when the typoe cannot be determined or no such argument exists. */
1929 static tree
1931 {
1935 tree argtype;
1936 function_args_iterator it;
1942 }
1944 /* Helper to append the "human readable" attribute access specification
1945 described by ACCESS to the array ATTRSTR with size STRSIZE. Used in
1946 diagnostics. */
1951 {
1958 }
1960 /* Iterate over attribute access read-only, read-write, and write-only
1961 arguments and diagnose past-the-end accesses and related problems
1962 in the function call EXP. */
1964 static void
1966 {
1967 auto_diagnostic_group adg;
1969 /* Set if a warning has been issued for any argument (used to decide
1970 whether to emit an informational note at the end). */
1973 /* A string describing the attributes that the warnings issued by this
1974 function apply to. Used to print one informational note per function
1975 call, rather than one per warning. That reduces clutter. */
1980 {
1983 /* Get the function call arguments corresponding to the attribute's
1984 positional arguments. When both arguments have been specified
1985 there will be two entries in *RWM, one for each. They are
1986 cross-referenced by their respective argument numbers in
1987 ACCESS.PTRARG and ACCESS.SIZARG. */
1994 /* The pointer is set to null for the entry corresponding to
1995 the size argument. Skip it. It's handled when the entry
1996 corresponding to the pointer argument comes up. */
2003 /* The size of the access by the call. */
2004 tree access_size;
2006 {
2007 /* If only the pointer attribute operand was specified and
2008 not size, set SIZE to the greater of MINSIZE or size of
2009 one element of the pointed to type to detect smaller
2010 objects (null pointers are diagnosed in this case only
2011 if the pointer is also declared with attribute nonnull. */
2015 else
2017 }
2018 else
2021 /* Format the value or range to avoid an explosion of messages. */
2025 {
2028 {
2031 }
2032 else
2033 {
2038 }
2039 }
2040 else
2043 /* Set if a warning has been issued for the current argument. */
2050 {
2051 /* Warn about negative sizes. */
2053 {
2058 "%Kbound argument %i value %s is "
2059 "negative for a variable length array "
2063 }
2064 else
2070 {
2072 /* Remember a warning has been issued and avoid warning
2073 again below for the same attribute. */
2076 }
2077 }
2080 {
2082 {
2083 /* Multiply ACCESS_SIZE by the size of the type the pointer
2084 argument points to. If it's incomplete the size is used
2085 as is. */
2088 {
2093 }
2094 }
2095 }
2096 else
2100 {
2102 {
2103 /* Warn about null pointers with positive sizes. This is
2104 different from also declaring the pointer argument with
2105 attribute nonnull when the function accepts null pointers
2106 only when the corresponding size is zero. */
2108 {
2113 "%Kargument %i of variable length "
2114 "array %s is null but "
2115 "the corresponding bound argument "
2119 }
2120 else
2122 "%Kargument %i is null but "
2123 "the corresponding size argument "
2126 sizstr);
2127 }
2129 {
2130 /* Warn about null pointers for [static N] array arguments
2131 but do not warn for ordinary (i.e., nonstatic) arrays. */
2133 "%Kargument %i to %<%T[static %E]%> "
2136 access_size);
2137 }
2140 {
2142 /* Remember a warning has been issued and avoid warning
2143 again below for the same attribute. */
2146 }
2147 }
2155 /* The size of the destination or source object. */
2159 {
2160 /* For a read-only argument there is no destination. For
2161 no access, set the source as well and differentiate via
2162 the access flag below. */
2166 {
2167 /* For a read-only attribute there is no destination so
2168 clear OBJSIZE. This emits "reading N bytes" kind of
2169 diagnostics instead of the "writing N bytes" kind,
2170 unless MODE is none. */
2172 }
2173 }
2174 else
2177 /* Clear the no-warning bit in case it was set by check_access
2178 in a prior iteration so that accesses via different arguments
2179 are diagnosed. */
2188 {
2194 else
2195 /* If check_access issued a warning above, append the relevant
2196 attribute to the string. */
2198 }
2199 }
2202 {
2207 else
2211 }
2213 {
2217 else
2220 }
2222 /* Set the bit in case if was cleared and not set above. */
2224 }
2226 /* Fill in ARGS_SIZE and ARGS array based on the parameters found in
2227 CALL_EXPR EXP.
2229 NUM_ACTUALS is the total number of parameters.
2231 N_NAMED_ARGS is the total number of named arguments.
2233 STRUCT_VALUE_ADDR_VALUE is the implicit argument for a struct return
2234 value, or null.
2236 FNDECL is the tree code for the target of this call (if known)
2238 ARGS_SO_FAR holds state needed by the target to know where to place
2239 the next argument.
2241 REG_PARM_STACK_SPACE is the number of bytes of stack space reserved
2242 for arguments which are passed in registers.
2244 OLD_STACK_LEVEL is a pointer to an rtx which olds the old stack level
2245 and may be modified by this routine.
2247 OLD_PENDING_ADJ, MUST_PREALLOCATE and FLAGS are pointers to integer
2248 flags which may be modified by this routine.
2250 MAY_TAILCALL is cleared if we encounter an invisible pass-by-reference
2251 that requires allocation of stack space.
2253 CALL_FROM_THUNK_P is true if this call is the jump from a thunk to
2254 the thunked-to function. */
2256 static void
2263 cumulative_args_t args_so_far,
2269 {
2273 /* Count arg position in order args appear. */
2283 /* In this loop, we consider args in the order they are written.
2284 We fill up ARGS from the back. */
2287 {
2289 call_expr_arg_iterator iter;
2290 tree arg;
2294 {
2296 j--;
2297 }
2300 {
2304 && argtype
2307 {
2310 j--;
2312 }
2313 else
2315 j--;
2316 argpos++;
2317 }
2321 }
2326 /* Extract attribute alloc_size from the type of the called expression
2327 (which could be a function or a function pointer) and if set, store
2328 the indices of the corresponding arguments in ALLOC_IDX, and then
2329 the actual argument(s) at those indices in ALLOC_ARGS. */
2332 {
2337 }
2339 /* Array for up to the two attribute alloc_size arguments. */
2342 /* Map of attribute accewss specifications for function arguments. */
2343 rdwr_map rdwr_idx;
2346 /* I counts args in order (to be) pushed; ARGPOS counts in order written. */
2348 {
2352 /* Replace erroneous argument with constant zero. */
2356 /* If TYPE is a transparent union or record, pass things the way
2357 we would pass the first field of the union or record. We have
2358 already verified that the modes are the same. */
2362 /* Decide where to pass this arg.
2364 args[i].reg is nonzero if all or part is passed in registers.
2366 args[i].partial is nonzero if part but not all is passed in registers,
2367 and the exact value says how many bytes are passed in registers.
2369 args[i].pass_on_stack is nonzero if the argument must at least be
2370 computed on the stack. It may then be loaded back into registers
2371 if args[i].reg is nonzero.
2373 These decisions are driven by the FUNCTION_... macros and must agree
2374 with those made by function.c. */
2376 /* See if this argument should be passed by invisible reference. */
2379 {
2385 /* If we're compiling a thunk, pass through invisible references
2386 instead of making a copy. */
2388 || (callee_copies
2393 {
2394 /* We may have turned the parameter value into an SSA name.
2395 Go back to the original parameter so we can take the
2396 address. */
2398 {
2402 }
2403 /* Argument setup code may have copied the value to register. We
2404 revert that optimization now because the tail call code must
2405 use the original location. */
2415 /* We can't use sibcalls if a callee-copied argument is
2416 stored in the current function's frame. */
2418 {
2421 "a callee-copied argument is"
2422 " stored in the current"
2424 }
2432 }
2433 else
2434 {
2435 /* We make a copy of the object and pass the address to the
2436 function being called. */
2437 rtx copy;
2444 {
2445 /* This is a variable-sized object. Make space on the stack
2446 for it. */
2450 {
2454 }
2456 /* We can pass TRUE as the 4th argument because we just
2457 saved the stack pointer and will restore it right after
2458 the call. */
2462 max_int_size_in_bytes
2467 }
2468 else
2473 /* Just change the const function to pure and then let
2474 the next test clear the pure based on
2475 callee_copies. */
2477 {
2480 }
2490 "argument must be passed"
2492 }
2494 }
2498 arg.mode
2512 /* If this is a sibling call and the machine has register windows, the
2513 register window has to be unwinded before calling the routine, so
2514 arguments have to go into the incoming registers. */
2518 else
2526 /* If FUNCTION_ARG returned a (parallel [(expr_list (nil) ...) ...]),
2527 it means that we are to pass this arg in the register(s) designated
2528 by the PARALLEL, but also to pass it in the stack. */
2533 /* If this is an addressable type, we must preallocate the stack
2534 since we must evaluate the object into its final location.
2536 If this is to be passed in both registers and the stack, it is simpler
2537 to preallocate. */
2542 /* Compute the stack-size of this argument. */
2547 #ifdef STACK_PARMS_IN_REG_PARM_AREA
2549 #else
2551 #endif
2552 reg_parm_stack_space,
2555 #ifdef BLOCK_REG_PADDING
2556 else
2557 /* The argument is passed entirely in registers. See at which
2558 end it should be padded. */
2562 #endif
2564 /* Update ARGS_SIZE, the total stack space for args so far. */
2570 /* Increment ARGS_SO_FAR, which has info about which arg-registers
2571 have been used, etc. */
2573 /* ??? Traditionally we've passed TYPE_MODE here, instead of the
2574 promoted_mode used for function_arg above. However, the
2575 corresponding handling of incoming arguments in function.c
2576 does pass the promoted mode. */
2580 /* Store argument values for functions decorated with attribute
2581 alloc_size. */
2587 /* Save the actual argument that corresponds to the access attribute
2588 operand for later processing. */
2590 {
2592 {
2594 // A nonnull ACCESS->SIZE contains VLA bounds. */
2595 }
2596 else
2597 {
2600 }
2601 }
2602 }
2605 {
2606 /* Check the arguments of functions decorated with attribute
2607 alloc_size. */
2609 }
2611 /* Detect passing non-string arguments to functions expecting
2612 nul-terminated strings. */
2615 /* Check attribute access arguments. */
2617 }
2619 /* Update ARGS_SIZE to contain the total size for the argument block.
2620 Return the original constant component of the argument block's size.
2622 REG_PARM_STACK_SPACE holds the number of bytes of stack space reserved
2623 for arguments passed in registers. */
2625 static poly_int64
2628 tree fndecl ATTRIBUTE_UNUSED,
2629 tree fntype ATTRIBUTE_UNUSED,
2631 {
2634 /* For accumulate outgoing args mode we don't need to align, since the frame
2635 will be already aligned. Align to STACK_BOUNDARY in order to prevent
2636 backends from generating misaligned frame sizes. */
2640 /* Compute the actual size of the argument block required. The variable
2641 and constant sizes must be combined, the size may have to be rounded,
2642 and there may be a minimum required size. */
2645 {
2651 {
2652 /* We don't handle this case yet. To handle it correctly we have
2653 to add the delta, round and subtract the delta.
2654 Currently no machine description requires this support. */
2656 preferred_stack_boundary));
2658 }
2661 {
2662 args_size->var
2666 /* The area corresponding to register parameters is not to count in
2667 the size of the block we need. So make the adjustment. */
2669 args_size->var
2672 }
2673 }
2674 else
2675 {
2681 preferred_stack_boundary)
2685 reg_parm_stack_space);
2689 }
2691 }
2693 /* Precompute parameters as needed for a function call.
2695 FLAGS is mask of ECF_* constants.
2697 NUM_ACTUALS is the number of arguments.
2699 ARGS is an array containing information for each argument; this
2700 routine fills in the INITIAL_VALUE and VALUE fields for each
2701 precomputed argument. */
2703 static void
2705 {
2708 /* If this is a libcall, then precompute all arguments so that we do not
2709 get extraneous instructions emitted as part of the libcall sequence. */
2711 /* If we preallocated the stack space, and some arguments must be passed
2712 on the stack, then we must precompute any parameter which contains a
2713 function call which will store arguments on the stack.
2714 Otherwise, evaluating the parameter may clobber previous parameters
2715 which have already been stored into the stack. (we have code to avoid
2716 such case by saving the outgoing stack arguments, but it results in
2717 worse code) */
2722 {
2723 tree type;
2724 machine_mode mode;
2729 /* If this is an addressable type, we cannot pre-evaluate it. */
2738 {
2744 /* CSE will replace this only if it contains args[i].value
2745 pseudo, so convert it down to the declared mode using
2746 a SUBREG. */
2750 {
2755 }
2756 }
2757 }
2758 }
2760 /* Given the current state of MUST_PREALLOCATE and information about
2761 arguments to a function call in NUM_ACTUALS, ARGS and ARGS_SIZE,
2762 compute and return the final value for MUST_PREALLOCATE. */
2764 static int
2767 {
2768 /* See if we have or want to preallocate stack space.
2770 If we would have to push a partially-in-regs parm
2771 before other stack parms, preallocate stack space instead.
2773 If the size of some parm is not a multiple of the required stack
2774 alignment, we must preallocate.
2776 If the total size of arguments that would otherwise create a copy in
2777 a temporary (such as a CALL) is more than half the total argument list
2778 size, preallocation is faster.
2780 Another reason to preallocate is if we have a machine (like the m88k)
2781 where stack alignment is required to be maintained between every
2782 pair of insns, not just when the call is made. However, we assume here
2783 that such machines either do not have push insns (and hence preallocation
2784 would occur anyway) or the problem is taken care of with
2785 PUSH_ROUNDING. */
2788 {
2794 {
2805 copy_to_evaluate_size
2807 }
2812 }
2814 }
2816 /* If we preallocated stack space, compute the address of each argument
2817 and store it into the ARGS array.
2819 We need not ensure it is a valid memory address here; it will be
2820 validized when it is used.
2822 ARGBLOCK is an rtx for the address of the outgoing arguments. */
2824 static void
2826 {
2828 {
2834 {
2837 }
2840 {
2843 rtx addr;
2848 /* Skip this parm if it will not be passed on the stack. */
2861 {
2862 /* Only part of the parameter is being passed on the stack.
2863 Generate a simple memory reference of the correct size. */
2869 }
2870 else
2871 {
2875 }
2878 poly_int64 offset_val;
2882 {
2884 unsigned int offset_align
2888 }
2895 {
2896 /* Only part of the parameter is being passed on the stack.
2897 Generate a simple memory reference of the correct size.
2898 */
2901 }
2902 else
2903 {
2907 }
2910 /* Function incoming arguments may overlap with sibling call
2911 outgoing arguments and we cannot allow reordering of reads
2912 from function arguments with stores to outgoing arguments
2913 of sibling calls. */
2916 }
2917 }
2918 }
2920 /* Given a FNDECL and EXP, return an rtx suitable for use as a target address
2921 in a call instruction.
2923 FNDECL is the tree node for the target function. For an indirect call
2924 FNDECL will be NULL_TREE.
2926 ADDR is the operand 0 of CALL_EXPR for this call. */
2928 static rtx
2930 {
2931 rtx funexp;
2933 /* Get the function to call, in the form of RTL. */
2935 {
2939 /* Get a SYMBOL_REF rtx for the function address. */
2941 }
2942 else
2943 /* Generate an rtx (probably a pseudo-register) for the address. */
2944 {
2948 }
2950 }
2952 /* Return the static chain for this function, if any. */
2954 rtx
2956 {
2961 }
2963 /* Internal state for internal_arg_pointer_based_exp and its helpers. */
2964 static struct
2965 {
2966 /* Last insn that has been scanned by internal_arg_pointer_based_exp_scan,
2967 or NULL_RTX if none has been scanned yet. */
2969 /* Vector indexed by REGNO - FIRST_PSEUDO_REGISTER, recording if a pseudo is
2970 based on crtl->args.internal_arg_pointer. The element is NULL_RTX if the
2971 pseudo isn't based on it, a CONST_INT offset if the pseudo is based on it
2972 with fixed offset, or PC if this is with variable or unknown offset. */
2978 /* Helper function for internal_arg_pointer_based_exp. Scan insns in
2979 the tail call sequence, starting with first insn that hasn't been
2980 scanned yet, and note for each pseudo on the LHS whether it is based
2981 on crtl->args.internal_arg_pointer or not, and what offset from that
2982 that pointer it has. */
2984 static void
2986 {
2991 else
2995 {
2998 {
3001 /* Punt on pseudos set multiple times. */
3006 else
3009 {
3011 internal_arg_pointer_exp_state.cache
3014 }
3015 }
3019 }
3022 }
3024 /* Compute whether RTL is based on crtl->args.internal_arg_pointer. Return
3025 NULL_RTX if RTL isn't based on it, a CONST_INT offset if RTL is based on
3026 it with fixed offset, or PC if this is with variable or unknown offset.
3027 TOPLEVEL is true if the function is invoked at the topmost level. */
3029 static rtx
3031 {
3041 poly_int64 offset;
3043 {
3048 }
3050 /* When called at the topmost level, scan pseudo assignments in between the
3051 last scanned instruction in the tail call sequence and the latest insn
3052 in that sequence. */
3057 {
3063 }
3067 {
3073 }
3076 }
3078 /* Return true if SIZE bytes starting from address ADDR might overlap an
3079 already-clobbered argument area. This function is used to determine
3080 if we should give up a sibcall. */
3082 static bool
3084 {
3085 poly_int64 i;
3087 rtx val;
3103 else
3109 /* We can ignore any references to the function's pretend args,
3110 which at this point would manifest as negative values of I. */
3127 }
3129 /* Do the register loads required for any wholly-register parms or any
3130 parms which are passed both on the stack and in a register. Their
3131 expressions were already evaluated.
3133 Mark all register-parms as living through the call, putting these USE
3134 insns in the CALL_INSN_FUNCTION_USAGE field.
3136 When IS_SIBCALL, perform the check_sibcall_argument_overlap
3137 checking, setting *SIBCALL_FAILURE if appropriate. */
3139 static void
3143 {
3147 {
3151 {
3160 /* Set non-negative if we must move a word at a time, even if
3161 just one word (e.g, partial == 4 && mode == DFmode). Set
3162 to -1 if we just use a normal move insn. This value can be
3163 zero if the argument is a zero size structure. */
3166 ;
3168 {
3171 }
3173 {
3174 /* Variable-sized parameters should be described by a
3175 PARALLEL instead. */
3180 }
3181 else
3184 /* Handle calls that pass values in multiple non-contiguous
3185 locations. The Irix 6 ABI has examples of this. */
3190 /* If simple case, just do move. If normal partial, store_one_arg
3191 has already loaded the register for us. In all other cases,
3192 load the register(s) from memory. */
3195 {
3197 #ifdef BLOCK_REG_PADDING
3198 /* Handle case where we have a value that needs shifting
3199 up to the msb. eg. a QImode value and we're padding
3200 upward on a BYTES_BIG_ENDIAN machine. */
3203 {
3206 {
3207 rtx x;
3208 poly_int64 shift
3211 /* Assigning REG here rather than a temp makes
3212 CALL_FUSAGE report the whole reg as used.
3213 Strictly speaking, the call only uses SIZE
3214 bytes at the msb end, but it doesn't seem worth
3215 generating rtl to say that. */
3221 }
3222 }
3223 #endif
3224 }
3226 /* If we have pre-computed the values to put in the registers in
3227 the case of non-aligned structures, copy them in now. */
3235 {
3236 /* SIZE and CONST_SIZE are 0 for partial arguments and
3237 the size of a BLKmode type otherwise. */
3241 /* Check for overlap with already clobbered argument area,
3242 providing that this has non-zero size. */
3245 && (mem_might_overlap_already_clobbered_arg_p
3252 else
3253 {
3262 NULL);
3268 }
3270 /* Handle a BLKmode that needs shifting. */
3272 #ifdef BLOCK_REG_PADDING
3274 #else
3275 && BYTES_BIG_ENDIAN
3276 #endif
3277 )
3278 {
3283 rtx x;
3288 }
3289 }
3291 /* When a parameter is a block, and perhaps in other cases, it is
3292 possible that it did a load from an argument slot that was
3293 already clobbered. */
3298 /* Handle calls that pass values in multiple non-contiguous
3299 locations. The Irix 6 ABI has examples of this. */
3306 }
3307 }
3308 }
3310 /* We need to pop PENDING_STACK_ADJUST bytes. But, if the arguments
3311 wouldn't fill up an even multiple of PREFERRED_UNIT_STACK_BOUNDARY
3312 bytes, then we would need to push some additional bytes to pad the
3313 arguments. So, we try to compute an adjust to the stack pointer for an
3314 amount that will leave the stack under-aligned by UNADJUSTED_ARGS_SIZE
3315 bytes. Then, when the arguments are pushed the stack will be perfectly
3316 aligned.
3318 Return true if this optimization is possible, storing the adjustment
3319 in ADJUSTMENT_OUT and setting ARGS_SIZE->CONSTANT to the number of
3320 bytes that should be popped after the call. */
3322 static bool
3324 poly_int64 unadjusted_args_size,
3327 {
3328 /* The number of bytes to pop so that the stack will be
3329 under-aligned by UNADJUSTED_ARGS_SIZE bytes. */
3330 poly_int64 adjustment;
3331 /* The alignment of the stack after the arguments are pushed, if we
3332 just pushed the arguments without adjust the stack here. */
3336 preferred_unit_stack_boundary,
3340 /* We want to get rid of as many of the PENDING_STACK_ADJUST bytes
3341 as possible -- leaving just enough left to cancel out the
3342 UNADJUSTED_ALIGNMENT. In other words, we want to ensure that the
3343 PENDING_STACK_ADJUST is non-negative, and congruent to
3344 -UNADJUSTED_ALIGNMENT modulo the PREFERRED_UNIT_STACK_BOUNDARY. */
3346 /* Begin by trying to pop all the bytes. */
3349 preferred_unit_stack_boundary,
3354 /* Push enough additional bytes that the stack will be aligned
3355 after the arguments are pushed. */
3359 /* We need to know whether the adjusted argument size
3360 (UNADJUSTED_ARGS_SIZE - ADJUSTMENT) constitutes an allocation
3361 or a deallocation. */
3365 /* Now, sets ARGS_SIZE->CONSTANT so that we pop the right number of
3366 bytes after the call. The right number is the entire
3367 PENDING_STACK_ADJUST less our ADJUSTMENT plus the amount required
3368 by the arguments in the first place. */
3369 args_size->constant
3374 }
3376 /* Scan X expression if it does not dereference any argument slots
3377 we already clobbered by tail call arguments (as noted in stored_args_map
3378 bitmap).
3379 Return nonzero if X expression dereferences such argument slots,
3380 zero otherwise. */
3382 static int
3384 {
3385 RTX_CODE code;
3394 /* We need not check the operands of the CALL expression itself. */
3402 /* Scan all subexpressions. */
3405 {
3407 {
3410 }
3412 {
3416 }
3417 }
3419 }
3421 /* Scan sequence after INSN if it does not dereference any argument slots
3422 we already clobbered by tail call arguments (as noted in stored_args_map
3423 bitmap). If MARK_STORED_ARGS_MAP, add stack slots for ARG to
3424 stored_args_map bitmap afterwards (when ARG is a register MARK_STORED_ARGS_MAP
3425 should be 0). Return nonzero if sequence after INSN dereferences such argument
3426 slots, zero otherwise. */
3428 static int
3431 {
3437 else
3446 {
3449 else
3457 else
3459 }
3461 }
3463 /* Given that a function returns a value of mode MODE at the most
3464 significant end of hard register VALUE, shift VALUE left or right
3465 as specified by LEFT_P. Return true if some action was needed. */
3467 bool
3469 {
3477 /* Use ashr rather than lshr for right shifts. This is for the benefit
3478 of the MIPS port, which requires SImode values to be sign-extended
3479 when stored in 64-bit registers. */
3485 }
3487 /* If X is a likely-spilled register value, copy it to a pseudo
3488 register and return that register. Return X otherwise. */
3490 static rtx
3492 {
3493 rtx new_rtx;
3498 {
3499 /* Make sure that we generate a REG rather than a CONCAT.
3500 Moves into CONCATs can need nontrivial instructions,
3501 and the whole point of this function is to avoid
3502 using the hard register directly in such a situation. */
3508 }
3510 }
3512 /* Helper function for expand_call.
3513 Return false is EXP is not implementable as a sibling call. */
3515 static bool
3517 rtx structure_value_addr,
3518 tree funtype,
3520 tree fndecl,
3522 tree addr,
3524 {
3526 {
3527 maybe_complain_about_tail_call
3529 "machine description does not have"
3532 }
3534 /* Doing sibling call optimization needs some work, since
3535 structure_value_addr can be allocated on the stack.
3536 It does not seem worth the effort since few optimizable
3537 sibling calls will return a structure. */
3539 {
3542 }
3544 #ifdef REG_PARM_STACK_SPACE
3545 /* If outgoing reg parm stack space changes, we cannot do sibcall. */
3549 {
3551 "inconsistent size of stack space"
3552 " allocated for arguments which are"
3555 }
3556 #endif
3558 /* Check whether the target is able to optimize the call
3559 into a sibcall. */
3561 {
3563 "target is not able to optimize the"
3566 }
3568 /* Functions that do not return exactly once may not be sibcall
3569 optimized. */
3571 {
3574 }
3576 {
3579 }
3582 {
3585 }
3587 /* If the called function is nested in the current one, it might access
3588 some of the caller's arguments, but could clobber them beforehand if
3589 the argument areas are shared. */
3591 {
3594 }
3596 /* If this function requires more stack slots than the current
3597 function, we cannot change it into a sibling call.
3598 crtl->args.pretend_args_size is not part of the
3599 stack allocated by our caller. */
3602 {
3604 "callee required more stack slots"
3607 }
3609 /* If the callee pops its own arguments, then it must pop exactly
3610 the same number of arguments as the current function. */
3614 TREE_TYPE
3617 {
3619 "inconsistent number of"
3622 }
3625 {
3629 }
3631 /* All checks passed. */
3633 }
3635 /* Update stack alignment when the parameter is passed in the stack
3636 since the outgoing parameter requires extra alignment on the calling
3637 function side. */
3639 static void
3641 {
3646 }
3648 /* Generate all the code for a CALL_EXPR exp
3649 and return an rtx for its value.
3650 Store the value in TARGET (specified as an rtx) if convenient.
3651 If the value is stored in TARGET then TARGET is returned.
3652 If IGNORE is nonzero, then we ignore the value of the function call. */
3654 rtx
3656 {
3657 /* Nonzero if we are currently expanding a call. */
3660 /* RTX for the function to be called. */
3661 rtx funexp;
3662 /* Sequence of insns to perform a normal "call". */
3664 /* Sequence of insns to perform a tail "call". */
3666 /* Data type of the function. */
3667 tree funtype;
3668 tree type_arg_types;
3669 tree rettype;
3670 /* Declaration of the function being called,
3671 or 0 if the function is computed (not known by name). */
3673 /* The type of the function being called. */
3674 tree fntype;
3679 /* Register in which non-BLKmode value will be returned,
3680 or 0 if no value or if value is BLKmode. */
3681 rtx valreg;
3682 /* Address where we should return a BLKmode value;
3683 0 if value not BLKmode. */
3685 /* Nonzero if that address is being passed by treating it as
3686 an extra, implicit first parameter. Otherwise,
3687 it is passed by being copied directly into struct_value_rtx. */
3689 /* Holds the value of implicit argument for the struct value. */
3691 /* Size of aggregate value wanted, or zero if none wanted
3692 or if we are using the non-reentrant PCC calling convention
3693 or expecting the value in registers. */
3695 /* Nonzero if called function returns an aggregate in memory PCC style,
3696 by returning the address of where to find it. */
3700 /* Number of actual parameters in this call, including struct value addr. */
3702 /* Number of named args. Args after this are anonymous ones
3703 and they must all go on the stack. */
3705 /* Number of complex actual arguments that need to be split. */
3708 /* Vector of information about each argument.
3709 Arguments are numbered in the order they will be pushed,
3710 not the order they are written. */
3713 /* Total size in bytes of all the stack-parms scanned so far. */
3716 /* Size of arguments before any adjustments (such as rounding). */
3717 poly_int64 unadjusted_args_size;
3718 /* Data on reg parms scanned so far. */
3719 CUMULATIVE_ARGS args_so_far_v;
3720 cumulative_args_t args_so_far;
3721 /* Nonzero if a reg parm has been scanned. */
3723 /* Nonzero if this is an indirect function call. */
3725 /* Nonzero if we must avoid push-insns in the args for this call.
3726 If stack space is allocated for register parameters, but not by the
3727 caller, then it is preallocated in the fixed part of the stack frame.
3728 So the entire argument block must then be preallocated (i.e., we
3729 ignore PUSH_ROUNDING in that case). */
3733 /* Size of the stack reserved for parameter registers. */
3736 /* Address of space preallocated for stack parms
3737 (on machines that lack push insns), or 0 if space not preallocated. */
3740 /* Mask of ECF_ and ERF_ flags. */
3743 #ifdef REG_PARM_STACK_SPACE
3744 /* Define the boundary of the register parm stack space that needs to be
3745 saved, if any. */
3748 #endif
3755 poly_int64 old_stack_allocated;
3757 /* State variables to track stack modifications. */
3763 /* Some stack pointer alterations we make are performed via
3764 allocate_dynamic_stack_space. This modifies the stack_pointer_delta,
3765 which we then also need to save/restore along the way. */
3768 rtx call_fusage;
3771 /* The alignment of the stack, in bits. */
3773 /* The alignment of the stack, in bytes. */
3775 /* The static chain value to use for this call. */
3776 rtx static_chain_value;
3777 /* See if this is "nothrow" function call. */
3781 /* See if we can find a DECL-node for the actual function, and get the
3782 function attributes (flags) from the function decl or type node. */
3785 {
3789 }
3790 else
3791 {
3796 }
3801 /* Warn if this value is an aggregate type,
3802 regardless of which calling convention we are using for it. */
3806 /* If the result of a non looping pure or const function call is
3807 ignored (or void), and none of its arguments are volatile, we can
3808 avoid expanding the call and just evaluate the arguments for
3809 side-effects. */
3814 {
3816 tree arg;
3817 call_expr_arg_iterator iter;
3821 {
3824 }
3827 {
3831 }
3832 }
3834 #ifdef REG_PARM_STACK_SPACE
3836 #endif
3842 /* Set up a place to return a structure. */
3844 /* Cater to broken compilers. */
3846 {
3847 /* This call returns a big structure. */
3850 #ifdef PCC_STATIC_STRUCT_RETURN
3851 {
3853 }
3855 {
3859 /* Even if it is semantically safe to use the target as the return
3860 slot, it may be not sufficiently aligned for the return type. */
3862 && target
3864 /* If rettype is addressable, we may not create a temporary.
3865 If target is properly aligned at runtime and the compiler
3866 just doesn't know about it, it will work fine, otherwise it
3867 will be UB. */
3873 else
3874 {
3875 /* For variable-sized objects, we must be called with a target
3876 specified. If we were to allocate space on the stack here,
3877 we would have no way of knowing when to free it. */
3881 }
3882 }
3884 }
3886 /* Figure out the amount to which the stack should be aligned. */
3889 {
3891 /* Without automatic stack alignment, we can't increase preferred
3892 stack boundary. With automatic stack alignment, it is
3893 unnecessary since unless we can guarantee that all callers will
3894 align the outgoing stack properly, callee has to align its
3895 stack anyway. */
3900 }
3902 /* Operand 0 is a pointer-to-function; get the type of the function. */
3907 /* Count whether there are actual complex arguments that need to be split
3908 into their real and imaginary parts. Munge the type_arg_types
3909 appropriately here as well. */
3911 {
3912 call_expr_arg_iterator iter;
3913 tree arg;
3915 {
3919 num_complex_actuals++;
3920 }
3922 }
3923 else
3929 /* If struct_value_rtx is 0, it means pass the address
3930 as if it were an extra parameter. Put the argument expression
3931 in structure_value_addr_value. */
3933 {
3934 /* If structure_value_addr is a REG other than
3935 virtual_outgoing_args_rtx, we can use always use it. If it
3936 is not a REG, we must always copy it into a register.
3937 If it is virtual_outgoing_args_rtx, we must copy it to another
3938 register in some cases. */
3940 || (ACCUMULATE_OUTGOING_ARGS
3941 && stack_arg_under_construction
3947 structure_value_addr_value =
3950 }
3952 /* Count the arguments and set NUM_ACTUALS. */
3953 num_actuals =
3956 /* Compute number of named args.
3957 First, do a raw count of the args for INIT_CUMULATIVE_ARGS. */
3960 n_named_args
3962 /* Count the struct value address, if it is passed as a parm. */
3964 else
3965 /* If we know nothing, treat all args as named. */
3968 /* Start updating where the next arg would go.
3970 On some machines (such as the PA) indirect calls have a different
3971 calling convention than normal calls. The fourth argument in
3972 INIT_CUMULATIVE_ARGS tells the backend if this is an indirect call
3973 or not. */
3977 /* Now possibly adjust the number of named args.
3978 Normally, don't include the last named arg if anonymous args follow.
3979 We do include the last named arg if
3980 targetm.calls.strict_argument_naming() returns nonzero.
3981 (If no anonymous args follow, the result of list_length is actually
3982 one too large. This is harmless.)
3984 If targetm.calls.pretend_outgoing_varargs_named() returns
3985 nonzero, and targetm.calls.strict_argument_naming() returns zero,
3986 this machine will be able to place unnamed args that were passed
3987 in registers into the stack. So treat all args as named. This
3988 allows the insns emitting for a specific argument list to be
3989 independent of the function declaration.
3991 If targetm.calls.pretend_outgoing_varargs_named() returns zero,
3992 we do not have any reliable way to pass unnamed args in
3993 registers, so we must force them into memory. */
3997 ;
4000 /* Don't include the last named arg. */
4002 else
4003 /* Treat all args as named. */
4006 /* Make a vector to hold all the information about each arg. */
4009 /* Build up entries in the ARGS array, compute the size of the
4010 arguments into ARGS_SIZE, etc. */
4022 /* Now make final decision about preallocating stack space. */
4027 /* If the structure value address will reference the stack pointer, we
4028 must stabilize it. We don't need to do this if we know that we are
4029 not going to adjust the stack pointer in processing this call. */
4034 structure_value_addr))
4036 || (!ACCUMULATE_OUTGOING_ARGS
4040 /* Tail calls can make things harder to debug, and we've traditionally
4041 pushed these optimizations into -O2. Don't try if we're already
4042 expanding a call, as that means we're an argument. Don't try if
4043 there's cleanups, as we know there's code to follow the call. */
4050 /* Workaround buggy C/C++ wrappers around Fortran routines with
4051 character(len=constant) arguments if the hidden string length arguments
4052 are passed on the stack; if the callers forget to pass those arguments,
4053 attempting to tail call in such routines leads to stack corruption.
4054 Avoid tail calls in functions where at least one such hidden string
4055 length argument is passed (partially or fully) on the stack in the
4056 caller and the callee needs to pass any arguments on the stack.
4057 See PR90329. */
4062 {
4066 {
4069 }
4070 }
4072 /* If the user has marked the function as requiring tail-call
4073 optimization, attempt it. */
4077 /* Rest of purposes for tail call optimizations to fail. */
4080 structure_value_addr,
4081 funtype,
4082 reg_parm_stack_space,
4083 fndecl,
4086 /* Check if caller and callee disagree in promotion of function
4087 return value. */
4089 {
4099 caller_promoted_mode
4103 callee_promoted_mode
4113 {
4116 "caller and callee disagree in"
4117 " promotion of function"
4119 }
4120 }
4122 /* Ensure current function's preferred stack boundary is at least
4123 what we need. Stack alignment may also increase preferred stack
4124 boundary. */
4133 else
4141 /* We want to make two insn chains; one for a sibling call, the other
4142 for a normal call. We will select one of the two chains after
4143 initial RTL generation is complete. */
4145 {
4147 /* We want to emit any pending stack adjustments before the tail
4148 recursion "call". That way we know any adjustment after the tail
4149 recursion call can be ignored if we indeed use the tail
4150 call expansion. */
4151 saved_pending_stack_adjust save;
4153 rtx next_arg_reg;
4156 {
4157 /* State variables we need to save and restore between
4158 iterations. */
4160 }
4163 else
4166 /* Other state variables that we must reinitialize each time
4167 through the loop (that are not initialized by the loop itself). */
4171 /* Start a new sequence for the normal call case.
4173 From this point on, if the sibling call fails, we want to set
4174 sibcall_failure instead of continuing the loop. */
4177 /* Don't let pending stack adjusts add up to too much.
4178 Also, do all pending adjustments now if there is any chance
4179 this might be a call to alloca or if we are expanding a sibling
4180 call sequence.
4181 Also do the adjustments before a throwing call, otherwise
4182 exception handling can fail; PR 19225. */
4191 /* Precompute any arguments as needed. */
4195 /* Now we are about to start emitting insns that can be deleted
4196 if a libcall is deleted. */
4206 /* Compute the actual size of the argument block required. The variable
4207 and constant sizes must be combined, the size may have to be rounded,
4208 and there may be a minimum required size. When generating a sibcall
4209 pattern, do not round up, since we'll be re-using whatever space our
4210 caller provided. */
4211 unadjusted_args_size
4220 /* The argument block when performing a sibling call is the
4221 incoming argument block. */
4223 {
4226 argblock
4228 else
4229 argblock
4236 }
4238 /* If we have no actual push instructions, or shouldn't use them,
4239 make space for all args right now. */
4241 {
4243 {
4248 /* stack_arg_under_construction says whether a stack arg is
4249 being constructed at the old stack level. Pushing the stack
4250 gets a clean outgoing argument block. */
4253 }
4257 }
4258 else
4259 {
4260 /* Note that we must go through the motions of allocating an argument
4261 block even if the size is zero because we may be storing args
4262 in the area reserved for register arguments, which may be part of
4263 the stack frame. */
4267 /* Store the maximum argument space used. It will be pushed by
4268 the prologue (if ACCUMULATE_OUTGOING_ARGS, or stack overflow
4269 checking). */
4272 needed);
4275 {
4277 {
4278 /* Since the stack pointer will never be pushed, it is
4279 possible for the evaluation of a parm to clobber
4280 something we have already written to the stack.
4281 Since most function calls on RISC machines do not use
4282 the stack, this is uncommon, but must work correctly.
4284 Therefore, we save any area of the stack that was already
4285 written and that we are using. Here we set up to do this
4286 by making a new stack usage map from the old one. The
4287 actual save will be done by store_one_arg.
4289 Another approach might be to try to reorder the argument
4290 evaluations to avoid this conflicting stack usage. */
4292 /* Since we will be writing into the entire argument area,
4293 the map must be allocated for its entire size, not just
4294 the part that is the responsibility of the caller. */
4302 /* For polynomial sizes, this is the maximum possible
4303 size needed for arguments with a constant size
4304 and offset. */
4306 highest_outgoing_arg_in_use
4315 initial_highest_arg_in_use);
4319 (highest_outgoing_arg_in_use
4323 /* The address of the outgoing argument list must not be
4324 copied to a register here, because argblock would be left
4325 pointing to the wrong place after the call to
4326 allocate_dynamic_stack_space below. */
4329 }
4330 else
4331 {
4332 /* Try to reuse some or all of the pending_stack_adjust
4333 to get this space. */
4335 && (combine_pending_stack_adjustment_and_call
4337 unadjusted_args_size,
4339 preferred_unit_stack_boundary)))
4340 {
4341 /* combine_pending_stack_adjustment_and_call computes
4342 an adjustment before the arguments are allocated.
4343 Account for them and see whether or not the stack
4344 needs to go up or down. */
4347 /* Checked by
4348 combine_pending_stack_adjustment_and_call. */
4351 {
4352 /* We're releasing stack space. */
4353 /* ??? We can avoid any adjustment at all if we're
4354 already aligned. FIXME. */
4358 }
4359 else
4360 /* We need to allocate space. We'll do that in
4361 push_block below. */
4363 }
4365 /* Special case this because overhead of `push_block' in
4366 this case is non-trivial. */
4369 else
4370 {
4375 }
4377 /* We only really need to call `copy_to_reg' in the case
4378 where push insns are going to be used to pass ARGBLOCK
4379 to a function call in ARGS. In that case, the stack
4380 pointer changes value from the allocation point to the
4381 call point, and hence the value of
4382 VIRTUAL_OUTGOING_ARGS_RTX changes as well. But might
4383 as well always do it. */
4385 }
4386 }
4387 }
4390 {
4391 /* The save/restore code in store_one_arg handles all
4392 cases except one: a constructor call (including a C
4393 function returning a BLKmode struct) to initialize
4394 an argument. */
4396 {
4397 rtx push_size
4398 = (gen_int_mode
4404 {
4409 /* stack_arg_under_construction says whether a stack
4410 arg is being constructed at the old stack level.
4411 Pushing the stack gets a clean outgoing argument
4412 block. */
4413 old_stack_arg_under_construction
4416 /* Make a new map for the new argument list. */
4422 }
4423 /* We can pass TRUE as the 4th argument because we just
4424 saved the stack pointer and will restore it right after
4425 the call. */
4428 }
4430 /* If argument evaluation might modify the stack pointer,
4431 copy the address of the argument list to a register. */
4434 {
4437 }
4438 }
4442 /* Stack is properly aligned, pops can't safely be deferred during
4443 the evaluation of the arguments. */
4444 NO_DEFER_POP;
4446 /* Precompute all register parameters. It isn't safe to compute
4447 anything once we have started filling any specific hard regs.
4448 TLS symbols sometimes need a call to resolve. Precompute
4449 register parameters before any stack pointer manipulation
4450 to avoid unaligned stack in the called function. */
4453 OK_DEFER_POP;
4455 /* Perform stack alignment before the first push (the last arg). */
4459 {
4460 /* When the stack adjustment is pending, we get better code
4461 by combining the adjustments. */
4463 && ! inhibit_defer_pop
4464 && (combine_pending_stack_adjustment_and_call
4466 unadjusted_args_size,
4468 preferred_unit_stack_boundary)))
4473 Pmode));
4474 }
4475 /* Now that the stack is properly aligned, pops can't safely
4476 be deferred during the evaluation of the arguments. */
4477 NO_DEFER_POP;
4479 /* Record the maximum pushed stack space size. We need to delay
4480 doing it this far to take into account the optimization done
4481 by combine_pending_stack_adjustment_and_call. */
4483 && !ACCUMULATE_OUTGOING_ARGS
4484 && pass
4486 {
4489 current_function_pushed_stack_size
4491 }
4497 else
4500 #ifdef REG_PARM_STACK_SPACE
4501 /* Save the fixed argument area if it's part of the caller's frame and
4502 is clobbered by argument setup for this call. */
4506 #endif
4508 /* Now store (and compute if necessary) all non-register parms.
4509 These come before register parms, since they can require block-moves,
4510 which could clobber the registers used for register parms.
4511 Parms which have partial registers are not stored here,
4512 but we do preallocate space here if they want that. */
4515 {
4517 {
4520 /* We don't allow passing huge (> 2^30 B) arguments
4521 by value. It would cause an overflow later on. */
4524 {
4527 }
4531 reg_parm_stack_space)
4536 }
4539 call_fusage
4542 call_fusage);
4543 }
4545 /* If we have a parm that is passed in registers but not in memory
4546 and whose alignment does not permit a direct copy into registers,
4547 make a group of pseudos that correspond to each register that we
4548 will later fill. */
4552 /* Now store any partially-in-registers parm.
4553 This is the last place a block-move can happen. */
4557 {
4560 /* On targets with weird calling conventions (e.g. PA) it's
4561 hard to ensure that all cases of argument overlap between
4562 stack and registers work. Play it safe and bail out. */
4564 {
4567 }
4571 reg_parm_stack_space)
4576 }
4581 {
4584 }
4588 /* Figure out the register where the value, if any, will come back. */
4592 {
4596 else
4600 /* If VALREG is a PARALLEL whose first member has a zero
4601 offset, use that. This is for targets such as m68k that
4602 return the same value in multiple places. */
4604 {
4611 }
4612 }
4614 /* If register arguments require space on the stack and stack space
4615 was not preallocated, allocate stack space here for arguments
4616 passed in registers. */
4618 && !ACCUMULATE_OUTGOING_ARGS
4622 /* Pass the function the address in which to return a
4623 structure value. */
4625 {
4626 structure_value_addr
4631 NULL_RTX)));
4635 }
4645 /* Save a pointer to the last insn before the call, so that we can
4646 later safely search backwards to find the CALL_INSN. */
4649 /* Set up next argument register. For sibling calls on machines
4650 with register windows this should be the incoming register. */
4654 else
4659 {
4665 && valreg
4668 call_fusage
4671 call_fusage);
4672 }
4673 /* All arguments and registers used for the call must be set up by
4674 now! */
4676 /* Stack must be properly aligned now. */
4679 preferred_unit_stack_boundary));
4681 /* Generate the actual call instruction. */
4688 {
4692 {
4696 }
4699 }
4701 /* If the call setup or the call itself overlaps with anything
4702 of the argument setup we probably clobbered our call address.
4703 In that case we can't do sibcalls. */
4708 /* If a non-BLKmode value is returned at the most significant end
4709 of a register, shift the register right by the appropriate amount
4710 and update VALREG accordingly. BLKmode values are handled by the
4711 group load/store machinery below. */
4713 && !pcc_struct_value
4718 {
4722 }
4725 {
4729 /* The return value from a malloc-like function is a pointer. */
4735 /* The return value from a malloc-like function cannot alias
4736 anything else. */
4740 /* Write out the sequence. */
4745 }
4747 /* For calls to `setjmp', etc., inform
4748 function.c:setjmp_warnings that it should complain if
4749 nonvolatile values are live. For functions that cannot
4750 return, inform flow that control does not fall through. */
4753 {
4754 /* The barrier must be emitted
4755 immediately after the CALL_INSN. Some ports emit more
4756 than just a CALL_INSN above, so we must search for it here. */
4760 {
4762 /* There was no CALL_INSN? */
4764 }
4768 /* Stack adjustments after a noreturn call are dead code.
4769 However when NO_DEFER_POP is in effect, we must preserve
4770 stack_pointer_delta. */
4772 {
4775 }
4776 }
4778 /* If value type not void, return an rtx for the value. */
4784 {
4786 {
4787 target
4790 structure_value_addr));
4792 }
4793 }
4795 {
4796 /* This is the special C++ case where we need to
4797 know what the true target was. We take care to
4798 never use this value more than once in one expression. */
4802 }
4803 /* Handle calls that return values in multiple non-contiguous locations.
4804 The Irix 6 ABI has examples of this. */
4806 {
4810 ;
4812 /* Handle the result of a emit_group_move_into_temps
4813 call in the previous pass. */
4815 else
4818 }
4822 {
4825 /* We have to copy a return value in a CLASS_LIKELY_SPILLED hard
4826 reg to a plain register. */
4830 /* If TARGET is a MEM in the argument area, and we have
4831 saved part of the argument area, then we can't store
4832 directly into TARGET as it may get overwritten when we
4833 restore the argument save area below. Don't work too
4834 hard though and simply force TARGET to a register if it
4835 is a MEM; the optimizer is quite likely to sort it out. */
4839 {
4842 }
4846 else
4847 {
4848 /* TARGET and VALREG cannot be equal at this point
4849 because the latter would not have
4850 REG_FUNCTION_VALUE_P true, while the former would if
4851 it were referring to the same register.
4853 If they refer to the same register, this move will be
4854 a no-op, except when function inlining is being
4855 done. */
4858 /* If we are setting a MEM, this code must be executed.
4859 Since it is emitted after the call insn, sibcall
4860 optimization cannot be performed in that case. */
4863 }
4864 }
4865 else
4868 /* If we promoted this return value, make the proper SUBREG.
4869 TARGET might be const0_rtx here, so be careful. */
4873 {
4876 machine_mode pmode;
4878 /* Ensure we promote as expected, and get the new unsignedness. */
4888 }
4890 /* If size of args is variable or this was a constructor call for a stack
4891 argument, restore saved stack-pointer value. */
4894 {
4909 }
4911 {
4912 #ifdef REG_PARM_STACK_SPACE
4916 #endif
4918 /* If we saved any argument areas, restore them. */
4921 {
4923 rtx stack_area
4930 else
4932 (gen_int_mode
4934 BLOCK_OP_CALL_PARM);
4935 }
4940 }
4942 /* If this was alloca, record the new stack level. */
4946 /* Free up storage we no longer need. */
4956 {
4959 /* Restore the pending stack adjustment now that we have
4960 finished generating the sibling call sequence. */
4964 /* Prepare arg structure for next iteration. */
4966 {
4970 }
4975 }
4976 else
4977 {
4980 /* Verify that we've deallocated all the stack we used. */
4983 stack_pointer_delta
4985 }
4987 /* If something prevents making this a sibling call,
4988 zero out the sequence. */
4991 else
4993 }
4995 /* If tail call production succeeded, we need to remove REG_EQUIV notes on
4996 arguments too, as argument area is now clobbered by the call. */
4998 {
5001 }
5002 else
5003 {
5006 /* Ideally we'd emit a message for all of the ways that it could
5007 have failed. */
5009 }
5011 currently_expanding_call--;
5016 }
5018 /* A sibling call sequence invalidates any REG_EQUIV notes made for
5019 this function's incoming arguments.
5021 At the start of RTL generation we know the only REG_EQUIV notes
5022 in the rtl chain are those for incoming arguments, so we can look
5023 for REG_EQUIV notes between the start of the function and the
5024 NOTE_INSN_FUNCTION_BEG.
5026 This is (slight) overkill. We could keep track of the highest
5027 argument we clobber and be more selective in removing notes, but it
5028 does not seem to be worth the effort. */
5030 void
5032 {
5036 {
5037 rtx note;
5039 /* There are never REG_EQUIV notes for the incoming arguments
5040 after the NOTE_INSN_FUNCTION_BEG note, so stop if we see it. */
5050 }
5051 }
5053 /* Traverse a list of TYPES and expand all complex types into their
5054 components. */
5055 static tree
5057 {
5058 tree p;
5060 /* Before allocating memory, check for the common case of no complex. */
5062 {
5067 }
5070 found:
5074 {
5079 {
5082 /* Rewrite complex type with component type. */
5086 /* Add another component type for the imaginary part. */
5091 /* Skip the newly created node. */
5093 }
5094 }
5097 }
5098 \f
5099 /* Output a library call to function ORGFUN (a SYMBOL_REF rtx)
5100 for a value of mode OUTMODE,
5101 with NARGS different arguments, passed as ARGS.
5102 Store the return value if RETVAL is nonzero: store it in VALUE if
5103 VALUE is nonnull, otherwise pick a convenient location. In either
5104 case return the location of the stored value.
5106 FN_TYPE should be LCT_NORMAL for `normal' calls, LCT_CONST for
5107 `const' calls, LCT_PURE for `pure' calls, or another LCT_ value for
5108 other types of library calls. */
5110 rtx
5114 {
5115 /* Total size in bytes of all the stack-parms scanned so far. */
5117 /* Size of arguments before any adjustments (such as rounding). */
5120 rtx fun;
5121 /* Todo, choose the correct decl type of orgfun. Sadly this information
5122 isn't present here, so we default to native calling abi here. */
5127 CUMULATIVE_ARGS args_so_far_v;
5128 cumulative_args_t args_so_far;
5129 struct arg
5130 {
5131 rtx value;
5132 machine_mode mode;
5133 rtx reg;
5136 rtx save_area;
5137 };
5142 rtx valreg;
5147 poly_int64 needed;
5152 #ifdef REG_PARM_STACK_SPACE
5153 /* Define the boundary of the register parm stack space that needs to be
5154 save, if any. */
5157 #endif
5159 /* Size of the stack reserved for parameter registers. */
5167 #ifdef REG_PARM_STACK_SPACE
5169 #endif
5171 /* By default, library functions cannot throw. */
5175 {
5193 }
5196 /* Ensure current function's preferred stack boundary is at least
5197 what we need. */
5201 /* If this kind of value comes back in memory,
5202 decide where in memory it should come back. */
5204 {
5207 {
5208 #ifdef PCC_STATIC_STRUCT_RETURN
5209 rtx pointer_reg
5219 else
5221 #endif
5222 /* This call returns a big structure. */
5224 }
5225 }
5226 else
5229 /* ??? Unfinished: must pass the memory address as an argument. */
5231 /* Copy all the libcall-arguments out of the varargs data
5232 and into a vector ARGVEC.
5234 Compute how to pass each argument. We only support a very small subset
5235 of the full argument passing conventions to limit complexity here since
5236 library functions shouldn't have many args. */
5241 #ifdef INIT_CUMULATIVE_LIBCALL_ARGS
5243 #else
5245 #endif
5255 /* If there's a structure value address to be passed,
5256 either pass it in the special place, or pass it as an extra argument. */
5258 {
5261 nargs++;
5263 /* Make sure it is a reasonable operand for a move or push insn. */
5278 #ifdef STACK_PARMS_IN_REG_PARM_AREA
5280 #else
5282 #endif
5292 count++;
5293 }
5296 {
5301 /* We cannot convert the arg value to the mode the library wants here;
5302 must do it earlier where we know the signedness of the arg. */
5307 /* Make sure it is a reasonable operand for a move or push insn. */
5314 {
5315 rtx slot;
5318 /* If this was a CONST function, it is now PURE since it now
5319 reads memory. */
5321 {
5324 }
5327 {
5332 }
5333 else
5334 {
5338 }
5342 call_fusage);
5346 slot),
5347 call_fusage);
5352 }
5358 unsigned_p);
5367 {
5369 #ifdef STACK_PARMS_IN_REG_PARM_AREA
5371 #else
5373 #endif
5378 }
5379 #ifdef BLOCK_REG_PADDING
5380 else
5381 /* The argument is passed entirely in registers. See at which
5382 end it should be padded. */
5386 UNITS_PER_WORD));
5387 #endif
5390 }
5398 /* If this machine requires an external definition for library
5399 functions, write one out. */
5405 STACK_BYTES)
5409 reg_parm_stack_space);
5418 {
5420 current_function_pushed_stack_size
5422 }
5425 {
5426 /* Since the stack pointer will never be pushed, it is possible for
5427 the evaluation of a parm to clobber something we have already
5428 written to the stack. Since most function calls on RISC machines
5429 do not use the stack, this is uncommon, but must work correctly.
5431 Therefore, we save any area of the stack that was already written
5432 and that we are using. Here we set up to do this by making a new
5433 stack usage map from the old one.
5435 Another approach might be to try to reorder the argument
5436 evaluations to avoid this conflicting stack usage. */
5440 /* Since we will be writing into the entire argument area, the
5441 map must be allocated for its entire size, not just the part that
5442 is the responsibility of the caller. */
5450 /* For polynomial sizes, this is the maximum possible size needed
5451 for arguments with a constant size and offset. */
5454 const_limit);
5461 initial_highest_arg_in_use);
5468 /* We must be careful to use virtual regs before they're instantiated,
5469 and real regs afterwards. Loop optimization, for example, can create
5470 new libcalls after we've instantiated the virtual regs, and if we
5471 use virtuals anyway, they won't match the rtl patterns. */
5475 STACK_POINTER_OFFSET);
5476 else
5478 }
5479 else
5480 {
5483 }
5485 /* We push args individually in reverse order, perform stack alignment
5486 before the first push (the last arg). */
5490 Pmode));
5494 #ifdef REG_PARM_STACK_SPACE
5496 {
5497 /* The argument list is the property of the called routine and it
5498 may clobber it. If the fixed area has been used for previous
5499 parameters, we must save and restore it. */
5502 }
5503 #endif
5505 /* When expanding a normal call, args are stored in push order,
5506 which is the reverse of what we have here. */
5510 {
5513 }
5517 /* Push the args that need to be pushed. */
5521 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
5522 are to be pushed. */
5524 {
5533 {
5534 rtx use;
5537 {
5538 /* If this is being stored into a pre-allocated, fixed-size,
5539 stack area, save any previous data at that location. */
5542 {
5543 /* stack_slot is negative, but we want to index stack_usage_map
5544 with positive values. */
5547 }
5548 else
5549 {
5552 }
5555 reg_parm_stack_space))
5556 {
5557 /* We need to make a save area. */
5558 poly_uint64 size
5560 machine_mode save_mode
5562 rtx adr
5565 rtx stack_area
5569 {
5573 );
5577 stack_area,
5578 (gen_int_mode
5580 Pmode)),
5581 BLOCK_OP_CALL_PARM);
5582 }
5583 else
5584 {
5588 }
5589 }
5590 }
5594 (gen_int_mode
5596 reg_parm_stack_space,
5599 /* Now mark the segment we just used. */
5603 NO_DEFER_POP;
5605 /* Indicate argument access so that alias.c knows that these
5606 values are live. */
5612 else
5613 {
5614 /* When arguments are pushed, trying to tell alias.c where
5615 exactly this argument is won't work, because the
5616 auto-increment causes confusion. So we merely indicate
5617 that we access something with a known mode somewhere on
5618 the stack. */
5622 }
5626 }
5627 }
5633 /* Now load any reg parms into their regs. */
5635 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
5636 are to be pushed. */
5638 {
5644 /* Handle calls that pass values in multiple non-contiguous
5645 locations. The PA64 has examples of this for library calls. */
5649 {
5651 #ifdef BLOCK_REG_PADDING
5654 /* Copied from load_register_parameters. */
5656 /* Handle case where we have a value that needs shifting
5657 up to the msb. eg. a QImode value and we're padding
5658 upward on a BYTES_BIG_ENDIAN machine. */
5662 {
5663 rtx x;
5666 /* Assigning REG here rather than a temp makes CALL_FUSAGE
5667 report the whole reg as used. Strictly speaking, the
5668 call only uses SIZE bytes at the msb end, but it doesn't
5669 seem worth generating rtl to say that. */
5674 }
5675 #endif
5676 }
5678 NO_DEFER_POP;
5679 }
5681 /* Any regs containing parms remain in use through the call. */
5683 {
5688 {
5691 {
5696 }
5697 else
5699 }
5700 }
5702 /* Pass the function the address in which to return a structure value. */
5704 {
5708 NULL_RTX)));
5711 }
5713 /* Don't allow popping to be deferred, since then
5714 cse'ing of library calls could delete a call and leave the pop. */
5715 NO_DEFER_POP;
5719 /* Stack must be properly aligned now. */
5728 /* We pass the old value of inhibit_defer_pop + 1 to emit_call_1, which
5729 will set inhibit_defer_pop to that value. */
5730 /* The return type is needed to decide how many bytes the function pops.
5731 Signedness plays no role in that, so for simplicity, we pretend it's
5732 always signed. We also assume that the list of arguments passed has
5733 no impact, so we pretend it is unknown. */
5739 struct_value_size,
5742 valreg,
5746 {
5751 }
5753 /* Right-shift returned value if necessary. */
5757 {
5760 }
5764 /* For calls to `setjmp', etc., inform function.c:setjmp_warnings
5765 that it should complain if nonvolatile values are live. For
5766 functions that cannot return, inform flow that control does not
5767 fall through. */
5769 {
5770 /* The barrier note must be emitted
5771 immediately after the CALL_INSN. Some ports emit more than
5772 just a CALL_INSN above, so we must search for it here. */
5775 {
5777 /* There was no CALL_INSN? */
5779 }
5782 }
5784 /* Consider that "regular" libcalls, i.e. all of them except for LCT_THROW
5785 and LCT_RETURNS_TWICE, cannot perform non-local gotos. */
5787 {
5790 {
5792 /* There was no CALL_INSN? */
5794 }
5797 }
5799 /* Now restore inhibit_defer_pop to its actual original value. */
5800 OK_DEFER_POP;
5804 /* Copy the value to the right place. */
5806 {
5808 {
5813 }
5815 {
5819 }
5820 else
5821 {
5822 /* Convert to the proper mode if a promotion has been active. */
5824 {
5831 }
5835 else
5837 }
5838 }
5841 {
5842 #ifdef REG_PARM_STACK_SPACE
5846 #endif
5848 /* If we saved any argument areas, restore them. */
5851 {
5860 validize_mem
5862 (gen_int_mode
5864 BLOCK_OP_CALL_PARM);
5865 else
5867 }
5872 }
5878 }
5879 \f
5881 /* Store a single argument for a function call
5882 into the register or memory area where it must be passed.
5883 *ARG describes the argument value and where to pass it.
5885 ARGBLOCK is the address of the stack-block for all the arguments,
5886 or 0 on a machine where arguments are pushed individually.
5888 MAY_BE_ALLOCA nonzero says this could be a call to `alloca'
5889 so must be careful about how the stack is used.
5891 VARIABLE_SIZE nonzero says that this was a variable-sized outgoing
5892 argument stack. This is used if ACCUMULATE_OUTGOING_ARGS to indicate
5893 that we need not worry about saving and restoring the stack.
5895 FNDECL is the declaration of the function we are calling.
5897 Return nonzero if this arg should cause sibcall failure,
5898 zero otherwise. */
5900 static int
5903 {
5914 /* Push a new temporary level for any temporaries we make for
5915 this argument. */
5919 {
5920 /* If this is being stored into a pre-allocated, fixed-size, stack area,
5921 save any previous data at that location. */
5923 {
5925 {
5926 /* stack_slot is negative, but we want to index stack_usage_map
5927 with positive values. */
5929 {
5932 }
5933 else
5937 }
5938 else
5939 {
5941 {
5944 }
5945 else
5949 }
5952 reg_parm_stack_space))
5953 {
5954 /* We need to make a save area. */
5956 machine_mode save_mode
5962 {
5963 arg->save_area
5967 stack_area,
5968 (gen_int_mode
5970 BLOCK_OP_CALL_PARM);
5971 }
5972 else
5973 {
5976 }
5977 }
5978 }
5979 }
5981 /* If this isn't going to be placed on both the stack and in registers,
5982 set up the register and number of words. */
5984 {
5987 else
5990 }
5992 /* Being passed entirely in a register. We shouldn't be called in
5993 this case. */
5996 /* If this arg needs special alignment, don't load the registers
5997 here. */
6001 /* If this is being passed partially in a register, we can't evaluate
6002 it directly into its stack slot. Otherwise, we can. */
6004 {
6005 /* stack_arg_under_construction is nonzero if a function argument is
6006 being evaluated directly into the outgoing argument list and
6007 expand_call must take special action to preserve the argument list
6008 if it is called recursively.
6010 For scalar function arguments stack_usage_map is sufficient to
6011 determine which stack slots must be saved and restored. Scalar
6012 arguments in general have pass_on_stack == 0.
6014 If this argument is initialized by a function which takes the
6015 address of the argument (a C++ constructor or a C function
6016 returning a BLKmode structure), then stack_usage_map is
6017 insufficient and expand_call must push the stack around the
6018 function call. Such arguments have pass_on_stack == 1.
6020 Note that it is always safe to set stack_arg_under_construction,
6021 but this generates suboptimal code if set when not needed. */
6024 stack_arg_under_construction++;
6027 (partial
6032 /* If we are promoting object (or for any other reason) the mode
6033 doesn't agree, convert the mode. */
6040 stack_arg_under_construction--;
6041 }
6043 /* Check for overlap with already clobbered argument area. */
6050 /* Don't allow anything left on stack from computation
6051 of argument to alloca. */
6056 /* If the value is already in the stack slot, we are done. */
6057 ;
6059 {
6062 /* Argument is a scalar, not entirely passed in registers.
6063 (If part is passed in registers, arg->partial says how much
6064 and emit_push_insn will take care of putting it there.)
6066 Push it, and if its size is less than the
6067 amount of space allocated to it,
6068 also bump stack pointer by the additional space.
6069 Note that in C the default argument promotions
6070 will prevent such mismatches. */
6075 /* Compute how much space the push instruction will push.
6076 On many machines, pushing a byte will advance the stack
6077 pointer by a halfword. */
6078 #ifdef PUSH_ROUNDING
6080 #endif
6083 /* Compute how much space the argument should get:
6084 round up to a multiple of the alignment for arguments. */
6087 /* At the moment we don't (need to) support ABIs for which the
6088 padding isn't known at compile time. In principle it should
6089 be easy to add though. */
6092 /* Compute the alignment of the pushed argument. */
6096 {
6101 }
6103 /* This isn't already where we want it on the stack, so put it there.
6104 This can either be done with push or copy insns. */
6109 reg_parm_stack_space,
6113 /* Unless this is a partially-in-register argument, the argument is now
6114 in the stack. */
6117 }
6118 else
6119 {
6120 /* BLKmode, at least partly to be pushed. */
6123 poly_int64 excess;
6124 rtx size_rtx;
6126 /* Pushing a nonscalar.
6127 If part is passed in registers, PARTIAL says how much
6128 and emit_push_insn will take care of putting it there. */
6130 /* Round its size up to a multiple
6131 of the allocation unit for arguments. */
6134 {
6137 }
6138 else
6139 {
6140 /* PUSH_ROUNDING has no effect on us, because emit_push_insn
6141 for BLKmode is careful to avoid it. */
6147 EXPAND_NORMAL);
6148 }
6152 /* When an argument is padded down, the block is aligned to
6153 PARM_BOUNDARY, but the actual argument isn't. */
6156 {
6159 else
6160 {
6161 unsigned int excess_align
6165 }
6166 }
6169 {
6170 /* emit_push_insn might not work properly if arg->value and
6171 argblock + arg->locate.offset areas overlap. */
6177 {
6178 /* arg.locate doesn't contain the pretend_args_size offset,
6179 it's part of argblock. Ensure we don't count it in I. */
6182 else
6185 /* expand_call should ensure this. */
6191 {
6192 /* Even though they appear to be at the same location,
6193 if part of the outgoing argument is in registers,
6194 they aren't really at the same location. Check for
6195 this by making sure that the incoming size is the
6196 same as the outgoing size. */
6199 }
6203 /* Use arg->locate.size.constant instead of size_rtx
6204 because we only care about the part of the argument
6205 on the stack. */
6209 }
6210 }
6216 reg_parm_stack_space,
6219 /* Unless this is a partially-in-register argument, the argument is now
6220 in the stack.
6222 ??? Unlike the case above, in which we want the actual
6223 address of the data, so that we can load it directly into a
6224 register, here we want the address of the stack slot, so that
6225 it's properly aligned for word-by-word copying or something
6226 like that. It's not clear that this is always correct. */
6229 }
6232 {
6234 arg->parallel_value
6237 }
6239 /* Mark all slots this store used. */
6244 /* Once we have pushed something, pops can't safely
6245 be deferred during the rest of the arguments. */
6246 NO_DEFER_POP;
6248 /* Free any temporary slots made in processing this argument. */
6252 }
6254 /* Nonzero if we do not know how to pass ARG solely in registers. */
6256 bool
6258 {
6262 /* If the type has variable size... */
6266 /* If the type is marked as addressable (it is required
6267 to be constructed into the stack)... */
6272 }
6274 /* Another version of the TARGET_MUST_PASS_IN_STACK hook. This one
6275 takes trailing padding of a structure into account. */
6276 /* ??? Should be able to merge these two by examining BLOCK_REG_PADDING. */
6278 bool
6280 {
6284 /* If the type has variable size... */
6288 /* If the type is marked as addressable (it is required
6289 to be constructed into the stack)... */
6296 /* If the padding and mode of the type is such that a copy into
6297 a register would put it into the wrong part of the register. */
6305 }
6307 /* Return true if TYPE must be passed on the stack when passed to
6308 the "..." arguments of a function. */
6310 bool
6312 {
6315 }
6317 /* Return true if FIELD is the C++17 empty base field that should
6318 be ignored for ABI calling convention decisions in order to
6319 maintain ABI compatibility between C++14 and earlier, which doesn't
6320 add this FIELD to classes with empty bases, and C++17 and later
6321 which does. */
6323 bool
6325 {
6330 }
6332 /* Tell the garbage collector about GTY markers in this source file. */