| blob | 3311d1cbe2b335678245f66ed04f3455b101186b |
1 /* Convert function calls to rtl insns, for GNU C compiler.
2 Copyright (C) 1989-2018 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/>. */
58 /* Like PREFERRED_STACK_BOUNDARY but in units of bytes, not bits. */
59 #define STACK_BYTES (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT)
61 /* Data structure and subroutines used within expand_call. */
63 struct arg_data
64 {
65 /* Tree node for this argument. */
66 tree tree_value;
67 /* Mode for value; TYPE_MODE unless promoted. */
68 machine_mode mode;
69 /* Current RTL value for argument, or 0 if it isn't precomputed. */
70 rtx value;
71 /* Initially-compute RTL value for argument; only for const functions. */
72 rtx initial_value;
73 /* Register to pass this argument in, 0 if passed on stack, or an
74 PARALLEL if the arg is to be copied into multiple non-contiguous
75 registers. */
76 rtx reg;
77 /* Register to pass this argument in when generating tail call sequence.
78 This is not the same register as for normal calls on machines with
79 register windows. */
80 rtx tail_call_reg;
81 /* If REG is a PARALLEL, this is a copy of VALUE pulled into the correct
82 form for emit_group_move. */
83 rtx parallel_value;
84 /* If value is passed in neither reg nor stack, this field holds a number
85 of a special slot to be used. */
86 rtx special_slot;
87 /* For pointer bounds hold an index of parm bounds are bound to. -1 if
88 there is no such pointer. */
90 /* If pointer_arg refers a structure, then pointer_offset holds an offset
91 of a pointer in this structure. */
93 /* If REG was promoted from the actual mode of the argument expression,
94 indicates whether the promotion is sign- or zero-extended. */
96 /* Number of bytes to put in registers. 0 means put the whole arg
97 in registers. Also 0 if not passed in registers. */
99 /* Nonzero if argument must be passed on stack.
100 Note that some arguments may be passed on the stack
101 even though pass_on_stack is zero, just because FUNCTION_ARG says so.
102 pass_on_stack identifies arguments that *cannot* go in registers. */
104 /* Some fields packaged up for locate_and_pad_parm. */
106 /* Location on the stack at which parameter should be stored. The store
107 has already been done if STACK == VALUE. */
108 rtx stack;
109 /* Location on the stack of the start of this argument slot. This can
110 differ from STACK if this arg pads downward. This location is known
111 to be aligned to TARGET_FUNCTION_ARG_BOUNDARY. */
112 rtx stack_slot;
113 /* Place that this stack area has been saved, if needed. */
114 rtx save_area;
115 /* If an argument's alignment does not permit direct copying into registers,
116 copy in smaller-sized pieces into pseudos. These are stored in a
117 block pointed to by this field. The next field says how many
118 word-sized pseudos we made. */
121 };
123 /* A vector of one char per byte of stack space. A byte if nonzero if
124 the corresponding stack location has been used.
125 This vector is used to prevent a function call within an argument from
126 clobbering any stack already set up. */
129 /* Size of STACK_USAGE_MAP. */
132 /* Assume that any stack location at this byte index is used,
133 without checking the contents of stack_usage_map. */
136 /* A bitmap of virtual-incoming stack space. Bit is set if the corresponding
137 stack location's tail call argument has been already stored into the stack.
138 This bitmap is used to prevent sibling call optimization if function tries
139 to use parent's incoming argument slots when they have been already
140 overwritten with tail call arguments. */
143 /* Assume that any virtual-incoming location at this byte index has been
144 stored, without checking the contents of stored_args_map. */
147 /* stack_arg_under_construction is nonzero when an argument may be
148 initialized with a constructor call (including a C function that
149 returns a BLKmode struct) and expand_call must take special action
150 to make sure the object being constructed does not overlap the
151 argument list for the constructor call. */
170 #ifdef REG_PARM_STACK_SPACE
173 #endif
174 \f
175 /* Return true if bytes [LOWER_BOUND, UPPER_BOUND) of the outgoing
176 stack region might already be in use. */
178 static bool
181 {
190 /* Don't worry about things in the fixed argument area;
191 it has already been saved. */
198 }
200 /* Record that bytes [LOWER_BOUND, UPPER_BOUND) of the outgoing
201 stack region are now in use. */
203 static void
205 {
211 else
213 }
215 /* Force FUNEXP into a form suitable for the address of a CALL,
216 and return that as an rtx. Also load the static chain register
217 if FNDECL is a nested function.
219 CALL_FUSAGE points to a variable holding the prospective
220 CALL_INSN_FUNCTION_USAGE information. */
222 rtx
225 {
226 /* Make a valid memory address and copy constants through pseudo-regs,
227 but not for a constant address if -fno-function-cse. */
229 {
230 /* If it's an indirect call by descriptor, generate code to perform
231 runtime identification of the pointer and load the descriptor. */
233 {
238 fndecl_or_type
240 fndecl_or_type);
247 /* Avoid long live ranges around function calls. */
253 /* Emit the runtime identification pattern. */
256 call_lab);
258 /* Statically predict the branch to very likely taken. */
263 /* Load the descriptor. */
272 POINTER_SIZE / BITS_PER_UNIT
281 {
284 }
286 /* Make sure we're not going to be overwritten below. */
288 }
290 /* If we are using registers for parameters, force the
291 function address into a register now. */
292 funexp = ((reg_parm_seen
296 }
297 else
298 {
299 /* funexp could be a SYMBOL_REF represents a function pointer which is
300 of ptr_mode. In this case, it should be converted into address mode
301 to be a valid address for memory rtx pattern. See PR 64971. */
306 {
309 }
310 }
315 {
316 rtx chain;
323 {
326 }
327 }
330 }
332 /* Generate instructions to call function FUNEXP,
333 and optionally pop the results.
334 The CALL_INSN is the first insn generated.
336 FNDECL is the declaration node of the function. This is given to the
337 hook TARGET_RETURN_POPS_ARGS to determine whether this function pops
338 its own args.
340 FUNTYPE is the data type of the function. This is given to the hook
341 TARGET_RETURN_POPS_ARGS to determine whether this function pops its
342 own args. We used to allow an identifier for library functions, but
343 that doesn't work when the return type is an aggregate type and the
344 calling convention says that the pointer to this aggregate is to be
345 popped by the callee.
347 STACK_SIZE is the number of bytes of arguments on the stack,
348 ROUNDED_STACK_SIZE is that number rounded up to
349 PREFERRED_STACK_BOUNDARY; zero if the size is variable. This is
350 both to put into the call insn and to generate explicit popping
351 code if necessary.
353 STRUCT_VALUE_SIZE is the number of bytes wanted in a structure value.
354 It is zero if this call doesn't want a structure value.
356 NEXT_ARG_REG is the rtx that results from executing
357 targetm.calls.function_arg (&args_so_far, VOIDmode, void_type_node, true)
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 /* Exclude functions not at the file scope, or not `extern',
597 since they are not the magic functions we would otherwise
598 think they are.
599 FIXME: this should be handled with attributes, not with this
600 hacky imitation of DECL_ASSEMBLER_NAME. It's (also) wrong
601 because you can declare fork() inside a function if you
602 wish. */
606 {
610 /* We assume that alloca will always be called by name. It
611 makes no sense to pass it as a pointer-to-function to
612 anything that does not understand its behavior. */
618 /* Disregard prefix _ or __. */
620 {
623 else
625 }
627 /* ECF_RETURNS_TWICE is safe even for -ffreestanding. */
634 }
641 }
643 /* Similar to special_function_p; return a set of ERF_ flags for the
644 function FNDECL. */
645 static int
647 {
648 tree attr;
662 {
675 }
676 }
678 /* Return nonzero when FNDECL represents a call to setjmp. */
680 int
682 {
686 }
689 /* Return true if STMT may be an alloca call. */
691 bool
693 {
694 tree fndecl;
704 }
706 /* Return true if STMT is a builtin alloca call. */
708 bool
710 {
711 tree fndecl;
719 {
720 CASE_BUILT_IN_ALLOCA:
724 }
727 }
729 /* Return true when exp contains a builtin alloca call. */
731 bool
733 {
734 tree fndecl;
739 {
740 CASE_BUILT_IN_ALLOCA:
744 }
747 }
749 /* Return TRUE if FNDECL is either a TM builtin or a TM cloned
750 function. Return FALSE otherwise. */
752 static bool
754 {
762 {
764 {
807 }
808 }
810 }
812 /* Detect flags (function attributes) from the function decl or type node. */
814 int
816 {
820 {
821 /* The function exp may have the `malloc' attribute. */
825 /* The function exp may have the `returns_twice' attribute. */
829 /* Process the pure and const attributes. */
848 {
855 }
858 }
860 {
868 }
869 else
873 {
877 }
880 }
882 /* Detect flags from a CALL_EXPR. */
884 int
886 {
894 else
895 {
899 else
903 }
906 }
908 /* Return true if TYPE should be passed by invisible reference. */
910 bool
913 {
915 {
916 /* If this type contains non-trivial constructors, then it is
917 forbidden for the middle-end to create any new copies. */
921 /* GCC post 3.4 passes *all* variable sized types by reference. */
925 /* If a record type should be passed the same as its first (and only)
926 member, use the type and mode of that member. */
928 {
931 }
932 }
936 }
938 /* Return true if TYPE, which is passed by reference, should be callee
939 copied instead of caller copied. */
941 bool
944 {
948 named_arg);
949 }
952 /* Precompute all register parameters as described by ARGS, storing values
953 into fields within the ARGS array.
955 NUM_ACTUALS indicates the total number elements in the ARGS array.
957 Set REG_PARM_SEEN if we encounter a register parameter. */
959 static void
962 {
969 {
973 {
978 }
980 /* If we are to promote the function arg to a wider mode,
981 do it now. */
989 /* If the value is a non-legitimate constant, force it into a
990 pseudo now. TLS symbols sometimes need a call to resolve. */
995 /* If we're going to have to load the value by parts, pull the
996 parts into pseudos. The part extraction process can involve
997 non-trivial computation. */
999 {
1004 }
1006 /* If the value is expensive, and we are inside an appropriately
1007 short loop, put the value into a pseudo and then put the pseudo
1008 into the hard reg.
1010 For small register classes, also do this if this call uses
1011 register parameters. This is to avoid reload conflicts while
1012 loading the parameters registers. */
1021 && ((*reg_parm_seen
1025 }
1026 }
1028 #ifdef REG_PARM_STACK_SPACE
1030 /* The argument list is the property of the called routine and it
1031 may clobber it. If the fixed area has been used for previous
1032 parameters, we must save and restore it. */
1034 static rtx
1035 save_fixed_argument_area (int reg_parm_stack_space, rtx argblock, int *low_to_save, int *high_to_save)
1036 {
1040 /* Compute the boundary of the area that needs to be saved, if any. */
1050 {
1052 machine_mode save_mode;
1054 rtx addr;
1055 rtx stack_area;
1056 rtx save_area;
1059 ;
1066 /* If we don't have the required alignment, must do this
1067 in BLKmode. */
1068 scalar_int_mode imode;
1073 else
1078 else
1086 {
1090 }
1091 else
1092 {
1095 }
1098 }
1101 }
1103 static void
1105 {
1112 else
1121 else
1124 BLOCK_OP_CALL_PARM);
1125 }
1128 /* If any elements in ARGS refer to parameters that are to be passed in
1129 registers, but not in memory, and whose alignment does not permit a
1130 direct copy into registers. Copy the values into a group of pseudos
1131 which we will later copy into the appropriate hard registers.
1133 Pseudos for each unaligned argument will be stored into the array
1134 args[argnum].aligned_regs. The caller is responsible for deallocating
1135 the aligned_regs array if it is nonzero. */
1137 static void
1139 {
1149 {
1154 {
1157 }
1158 else
1159 {
1162 }
1166 /* Structures smaller than a word are normally aligned to the
1167 least significant byte. On a BYTES_BIG_ENDIAN machine,
1168 this means we must skip the empty high order bytes when
1169 calculating the bit offset. */
1171 #ifdef BLOCK_REG_PADDING
1175 #else
1176 && BYTES_BIG_ENDIAN
1177 #endif
1178 )
1182 {
1191 /* There is no need to restrict this code to loading items
1192 in TYPE_ALIGN sized hunks. The bitfield instructions can
1193 load up entire word sized registers efficiently.
1195 ??? This may not be needed anymore.
1196 We use to emit a clobber here but that doesn't let later
1197 passes optimize the instructions we emit. By storing 0 into
1198 the register later passes know the first AND to zero out the
1199 bitfield being set in the register is unnecessary. The store
1200 of 0 will be deleted as will at least the first AND. */
1207 }
1208 }
1209 }
1211 /* The limit set by -Walloc-larger-than=. */
1214 /* Initialize ALLOC_OBJECT_SIZE_LIMIT based on the -Walloc-size-larger-than=
1215 setting if the option is specified, or to the maximum object size if it
1216 is not. Return the initialized value. */
1218 static tree
1220 {
1234 unsigned HOST_WIDE_INT limit
1237 /* If the value is too large to be represented use the maximum
1238 representable value that strtoull sets limit to (setting
1239 errno to ERANGE). */
1242 {
1243 /* Numeric option arguments are at most INT_MAX. Make it
1244 possible to specify a larger value by accepting common
1245 suffixes. */
1272 else
1273 {
1274 /* This could mean an unknown suffix or a bad prefix, like
1275 "+-1". */
1280 /* Ignore the limit extracted by strtoull. */
1282 }
1283 }
1286 {
1289 alloc_object_size_limit
1291 else
1293 }
1297 }
1299 /* Return true when EXP's range can be determined and set RANGE[] to it
1300 after adjusting it if necessary to make EXP a represents a valid size
1301 of object, or a valid size argument to an allocation function declared
1302 with attribute alloc_size (whose argument may be signed), or to a string
1303 manipulation function like memset. When ALLOW_ZERO is true, allow
1304 returning a range of [0, 0] for a size in an anti-range [1, N] where
1305 N > PTRDIFF_MAX. A zero range is a (nearly) invalid argument to
1306 allocation functions like malloc but it is a valid argument to
1307 functions like memset. */
1309 bool
1311 {
1313 {
1314 /* EXP is a constant. */
1317 }
1327 else
1331 {
1333 {
1334 /* Use the full range of the type of the expression when
1335 no value range information is available. */
1339 }
1344 }
1351 {
1353 {
1355 {
1356 /* EXP is not in a strictly negative range. That means
1357 it must be in some (not necessarily strictly) positive
1358 range which includes zero. Since in signed to unsigned
1359 conversions negative values end up converted to large
1360 positive values, and otherwise they are not valid sizes,
1361 the resulting range is in both cases [0, TYPE_MAX]. */
1364 }
1366 {
1367 /* EXP is not in a negative-positive range. That means EXP
1368 is either negative, or greater than max. Since negative
1369 sizes are invalid make the range [MAX + 1, TYPE_MAX]. */
1372 }
1373 else
1374 {
1377 }
1378 }
1380 {
1381 /* EXP is unsigned and not in the range [1, MAX]. That means
1382 it's either zero or greater than MAX. Even though 0 would
1383 normally be detected by -Walloc-zero, unless ALLOW_ZERO
1384 is true, set the range to [MAX, TYPE_MAX] so that when MAX
1385 is greater than the limit the whole range is diagnosed. */
1388 else
1389 {
1392 }
1393 }
1394 else
1395 {
1398 }
1399 }
1405 }
1407 /* Diagnose a call EXP to function FN decorated with attribute alloc_size
1408 whose argument numbers given by IDX with values given by ARGS exceed
1409 the maximum object size or cause an unsigned oveflow (wrapping) when
1410 multiplied. When ARGS[0] is null the function does nothing. ARGS[1]
1411 may be null for functions like malloc, and non-null for those like
1412 calloc that are decorated with a two-argument attribute alloc_size. */
1414 void
1416 {
1417 /* The range each of the (up to) two arguments is known to be in. */
1420 /* Maximum object size set by -Walloc-size-larger-than= or SIZE_MAX / 2. */
1427 /* Validate each argument individually. */
1429 {
1431 {
1436 {
1440 }
1442 {
1443 /* Avoid issuing -Walloc-zero for allocation functions other
1444 than __builtin_alloca that are declared with attribute
1445 returns_nonnull because there's no portability risk. This
1446 avoids warning for such calls to libiberty's xmalloc and
1447 friends.
1448 Also avoid issuing the warning for calls to function named
1449 "alloca". */
1458 }
1460 {
1461 /* G++ emits calls to ::operator new[](SIZE_MAX) in C++98
1462 mode and with -fno-exceptions as a way to indicate array
1463 size overflow. There's no good way to detect C++98 here
1464 so avoid diagnosing these calls for all C++ modes. */
1473 "%Kargument %i value %qE exceeds "
1476 }
1477 }
1480 {
1481 /* Verify that the argument's range is not negative (including
1482 upper bound of zero). */
1485 {
1490 }
1492 {
1494 "%Kargument %i range [%E, %E] exceeds "
1498 maxobjsize);
1499 }
1500 }
1501 }
1506 /* For a two-argument alloc_size, validate the product of the two
1507 arguments if both of their values or ranges are known. */
1512 {
1513 /* Check for overflow in the product of a function decorated with
1514 attribute alloc_size (X, Y). */
1524 "%Kproduct %<%E * %E%> of arguments %i and %i "
1530 "%Kproduct %<%E * %E%> of arguments %i and %i "
1534 maxobjsize);
1537 {
1538 /* Print the full range of each of the two arguments to make
1539 it clear when it is, in fact, in a range and not constant. */
1546 }
1547 }
1550 {
1556 else
1559 }
1560 }
1562 /* If EXPR refers to a character array or pointer declared attribute
1563 nonstring return a decl for that array or pointer and set *REF to
1564 the referenced enclosing object or pointer. Otherwise returns
1565 null. */
1567 tree
1569 {
1572 {
1576 {
1582 }
1585 }
1605 }
1607 /* Warn about passing a non-string array/pointer to a function that
1608 expects a nul-terminated string argument. */
1610 void
1612 {
1618 /* The bound argument to a bounded string function like strncpy. */
1621 /* The range of lengths of a string argument to one of the comparison
1622 functions. If the length is less than the bound it is used instead. */
1625 /* It's safe to call "bounded" string functions with a non-string
1626 argument since the functions provide an explicit bound for this
1627 purpose. */
1629 {
1633 {
1634 /* For these, if one argument refers to one or more of a set
1635 of string constants or arrays of known size, determine
1636 the range of their known or possible lengths and use it
1637 conservatively as the bound for the unbounded function,
1638 and to adjust the range of the bound of the bounded ones. */
1640 {
1644 }
1645 }
1646 /* Fall through. */
1650 {
1655 }
1658 {
1663 }
1667 }
1669 /* Determine the range of the bound argument (if specified). */
1672 {
1675 }
1678 {
1679 /* Add one for the nul. */
1686 {
1687 /* Conservatively use the upper bound of the lengths for
1688 both the lower and the upper bound of the operation. */
1692 }
1693 else
1694 {
1695 /* Replace the bound on the operation with the upper bound
1696 of the length of the string if the latter is smaller. */
1701 }
1702 }
1704 /* Iterate over the built-in function's formal arguments and check
1705 each const char* against the actual argument. If the actual
1706 argument is declared attribute non-string issue a warning unless
1707 the argument's maximum length is bounded. */
1708 function_args_iterator it;
1712 {
1713 /* Avoid iterating past the declared argument in a call
1714 to function declared without a prototype. */
1739 /* See if the destination is declared with attribute "nonstring". */
1746 /* The maximum number of array elements accessed. */
1751 /* Size of the array. */
1754 /* Determine the array size. For arrays of unknown bound and
1755 pointers reset BOUND to trigger the appropriate warning. */
1757 {
1759 {
1762 }
1765 }
1775 "%qD argument %i declared attribute %<nonstring%> "
1786 }
1787 }
1789 /* Issue an error if CALL_EXPR was flagged as requiring
1790 tall-call optimization. */
1792 static void
1794 {
1800 }
1802 /* Fill in ARGS_SIZE and ARGS array based on the parameters found in
1803 CALL_EXPR EXP.
1805 NUM_ACTUALS is the total number of parameters.
1807 N_NAMED_ARGS is the total number of named arguments.
1809 STRUCT_VALUE_ADDR_VALUE is the implicit argument for a struct return
1810 value, or null.
1812 FNDECL is the tree code for the target of this call (if known)
1814 ARGS_SO_FAR holds state needed by the target to know where to place
1815 the next argument.
1817 REG_PARM_STACK_SPACE is the number of bytes of stack space reserved
1818 for arguments which are passed in registers.
1820 OLD_STACK_LEVEL is a pointer to an rtx which olds the old stack level
1821 and may be modified by this routine.
1823 OLD_PENDING_ADJ, MUST_PREALLOCATE and FLAGS are pointers to integer
1824 flags which may be modified by this routine.
1826 MAY_TAILCALL is cleared if we encounter an invisible pass-by-reference
1827 that requires allocation of stack space.
1829 CALL_FROM_THUNK_P is true if this call is the jump from a thunk to
1830 the thunked-to function. */
1832 static void
1839 cumulative_args_t args_so_far,
1845 {
1849 /* Count arg position in order args appear. */
1859 /* In this loop, we consider args in the order they are written.
1860 We fill up ARGS from the back. */
1863 {
1865 call_expr_arg_iterator iter;
1866 tree arg;
1870 {
1872 j--;
1873 }
1876 {
1880 && argtype
1883 {
1886 j--;
1888 }
1889 else
1891 j--;
1892 argpos++;
1893 }
1897 }
1901 /* Extract attribute alloc_size and if set, store the indices of
1902 the corresponding arguments in ALLOC_IDX, and then the actual
1903 argument(s) at those indices in ALLOC_ARGS. */
1909 {
1914 }
1916 /* Array for up to the two attribute alloc_size arguments. */
1919 /* I counts args in order (to be) pushed; ARGPOS counts in order written. */
1921 {
1924 machine_mode mode;
1926 /* Replace erroneous argument with constant zero. */
1930 /* If TYPE is a transparent union or record, pass things the way
1931 we would pass the first field of the union or record. We have
1932 already verified that the modes are the same. */
1937 /* Decide where to pass this arg.
1939 args[i].reg is nonzero if all or part is passed in registers.
1941 args[i].partial is nonzero if part but not all is passed in registers,
1942 and the exact value says how many bytes are passed in registers.
1944 args[i].pass_on_stack is nonzero if the argument must at least be
1945 computed on the stack. It may then be loaded back into registers
1946 if args[i].reg is nonzero.
1948 These decisions are driven by the FUNCTION_... macros and must agree
1949 with those made by function.c. */
1951 /* See if this argument should be passed by invisible reference. */
1954 {
1958 callee_copies
1962 /* If we're compiling a thunk, pass through invisible references
1963 instead of making a copy. */
1965 || (callee_copies
1970 {
1971 /* We may have turned the parameter value into an SSA name.
1972 Go back to the original parameter so we can take the
1973 address. */
1975 {
1979 }
1980 /* Argument setup code may have copied the value to register. We
1981 revert that optimization now because the tail call code must
1982 use the original location. */
1992 /* We can't use sibcalls if a callee-copied argument is
1993 stored in the current function's frame. */
1995 {
1998 "a callee-copied argument is"
1999 " stored in the current"
2001 }
2009 }
2010 else
2011 {
2012 /* We make a copy of the object and pass the address to the
2013 function being called. */
2014 rtx copy;
2021 {
2022 /* This is a variable-sized object. Make space on the stack
2023 for it. */
2027 {
2031 }
2033 /* We can pass TRUE as the 4th argument because we just
2034 saved the stack pointer and will restore it right after
2035 the call. */
2039 max_int_size_in_bytes
2044 }
2045 else
2050 /* Just change the const function to pure and then let
2051 the next test clear the pure based on
2052 callee_copies. */
2054 {
2057 }
2067 "argument must be passed"
2069 }
2070 }
2085 {
2088 }
2090 /* If this is a sibling call and the machine has register windows, the
2091 register window has to be unwinded before calling the routine, so
2092 arguments have to go into the incoming registers. */
2097 else
2107 /* If FUNCTION_ARG returned a (parallel [(expr_list (nil) ...) ...]),
2108 it means that we are to pass this arg in the register(s) designated
2109 by the PARALLEL, but also to pass it in the stack. */
2114 /* If this is an addressable type, we must preallocate the stack
2115 since we must evaluate the object into its final location.
2117 If this is to be passed in both registers and the stack, it is simpler
2118 to preallocate. */
2123 /* Compute the stack-size of this argument. */
2128 #ifdef STACK_PARMS_IN_REG_PARM_AREA
2130 #else
2132 #endif
2133 reg_parm_stack_space,
2136 #ifdef BLOCK_REG_PADDING
2137 else
2138 /* The argument is passed entirely in registers. See at which
2139 end it should be padded. */
2143 #endif
2145 /* Update ARGS_SIZE, the total stack space for args so far. */
2151 /* Increment ARGS_SO_FAR, which has info about which arg-registers
2152 have been used, etc. */
2157 /* Store argument values for functions decorated with attribute
2158 alloc_size. */
2163 }
2166 {
2167 /* Check the arguments of functions decorated with attribute
2168 alloc_size. */
2170 }
2172 /* Detect passing non-string arguments to functions expecting
2173 nul-terminated strings. */
2175 }
2177 /* Update ARGS_SIZE to contain the total size for the argument block.
2178 Return the original constant component of the argument block's size.
2180 REG_PARM_STACK_SPACE holds the number of bytes of stack space reserved
2181 for arguments passed in registers. */
2183 static poly_int64
2186 tree fndecl ATTRIBUTE_UNUSED,
2187 tree fntype ATTRIBUTE_UNUSED,
2189 {
2192 /* For accumulate outgoing args mode we don't need to align, since the frame
2193 will be already aligned. Align to STACK_BOUNDARY in order to prevent
2194 backends from generating misaligned frame sizes. */
2198 /* Compute the actual size of the argument block required. The variable
2199 and constant sizes must be combined, the size may have to be rounded,
2200 and there may be a minimum required size. */
2203 {
2209 {
2210 /* We don't handle this case yet. To handle it correctly we have
2211 to add the delta, round and subtract the delta.
2212 Currently no machine description requires this support. */
2214 preferred_stack_boundary));
2216 }
2219 {
2220 args_size->var
2224 /* The area corresponding to register parameters is not to count in
2225 the size of the block we need. So make the adjustment. */
2227 args_size->var
2230 }
2231 }
2232 else
2233 {
2239 preferred_stack_boundary)
2243 reg_parm_stack_space);
2247 }
2249 }
2251 /* Precompute parameters as needed for a function call.
2253 FLAGS is mask of ECF_* constants.
2255 NUM_ACTUALS is the number of arguments.
2257 ARGS is an array containing information for each argument; this
2258 routine fills in the INITIAL_VALUE and VALUE fields for each
2259 precomputed argument. */
2261 static void
2263 {
2266 /* If this is a libcall, then precompute all arguments so that we do not
2267 get extraneous instructions emitted as part of the libcall sequence. */
2269 /* If we preallocated the stack space, and some arguments must be passed
2270 on the stack, then we must precompute any parameter which contains a
2271 function call which will store arguments on the stack.
2272 Otherwise, evaluating the parameter may clobber previous parameters
2273 which have already been stored into the stack. (we have code to avoid
2274 such case by saving the outgoing stack arguments, but it results in
2275 worse code) */
2280 {
2281 tree type;
2282 machine_mode mode;
2287 /* If this is an addressable type, we cannot pre-evaluate it. */
2296 {
2302 /* CSE will replace this only if it contains args[i].value
2303 pseudo, so convert it down to the declared mode using
2304 a SUBREG. */
2308 {
2313 }
2314 }
2315 }
2316 }
2318 /* Given the current state of MUST_PREALLOCATE and information about
2319 arguments to a function call in NUM_ACTUALS, ARGS and ARGS_SIZE,
2320 compute and return the final value for MUST_PREALLOCATE. */
2322 static int
2325 {
2326 /* See if we have or want to preallocate stack space.
2328 If we would have to push a partially-in-regs parm
2329 before other stack parms, preallocate stack space instead.
2331 If the size of some parm is not a multiple of the required stack
2332 alignment, we must preallocate.
2334 If the total size of arguments that would otherwise create a copy in
2335 a temporary (such as a CALL) is more than half the total argument list
2336 size, preallocation is faster.
2338 Another reason to preallocate is if we have a machine (like the m88k)
2339 where stack alignment is required to be maintained between every
2340 pair of insns, not just when the call is made. However, we assume here
2341 that such machines either do not have push insns (and hence preallocation
2342 would occur anyway) or the problem is taken care of with
2343 PUSH_ROUNDING. */
2346 {
2352 {
2363 copy_to_evaluate_size
2365 }
2370 }
2372 }
2374 /* If we preallocated stack space, compute the address of each argument
2375 and store it into the ARGS array.
2377 We need not ensure it is a valid memory address here; it will be
2378 validized when it is used.
2380 ARGBLOCK is an rtx for the address of the outgoing arguments. */
2382 static void
2384 {
2386 {
2392 {
2395 }
2398 {
2401 rtx addr;
2406 /* Skip this parm if it will not be passed on the stack. */
2419 {
2420 /* Only part of the parameter is being passed on the stack.
2421 Generate a simple memory reference of the correct size. */
2427 }
2428 else
2429 {
2433 }
2436 poly_int64 offset_val;
2440 {
2442 unsigned int offset_align
2446 }
2453 {
2454 /* Only part of the parameter is being passed on the stack.
2455 Generate a simple memory reference of the correct size.
2456 */
2459 }
2460 else
2461 {
2465 }
2468 /* Function incoming arguments may overlap with sibling call
2469 outgoing arguments and we cannot allow reordering of reads
2470 from function arguments with stores to outgoing arguments
2471 of sibling calls. */
2474 }
2475 }
2476 }
2478 /* Given a FNDECL and EXP, return an rtx suitable for use as a target address
2479 in a call instruction.
2481 FNDECL is the tree node for the target function. For an indirect call
2482 FNDECL will be NULL_TREE.
2484 ADDR is the operand 0 of CALL_EXPR for this call. */
2486 static rtx
2488 {
2489 rtx funexp;
2491 /* Get the function to call, in the form of RTL. */
2493 {
2497 /* Get a SYMBOL_REF rtx for the function address. */
2499 }
2500 else
2501 /* Generate an rtx (probably a pseudo-register) for the address. */
2502 {
2506 }
2508 }
2510 /* Return the static chain for this function, if any. */
2512 rtx
2514 {
2519 }
2521 /* Internal state for internal_arg_pointer_based_exp and its helpers. */
2522 static struct
2523 {
2524 /* Last insn that has been scanned by internal_arg_pointer_based_exp_scan,
2525 or NULL_RTX if none has been scanned yet. */
2527 /* Vector indexed by REGNO - FIRST_PSEUDO_REGISTER, recording if a pseudo is
2528 based on crtl->args.internal_arg_pointer. The element is NULL_RTX if the
2529 pseudo isn't based on it, a CONST_INT offset if the pseudo is based on it
2530 with fixed offset, or PC if this is with variable or unknown offset. */
2536 /* Helper function for internal_arg_pointer_based_exp. Scan insns in
2537 the tail call sequence, starting with first insn that hasn't been
2538 scanned yet, and note for each pseudo on the LHS whether it is based
2539 on crtl->args.internal_arg_pointer or not, and what offset from that
2540 that pointer it has. */
2542 static void
2544 {
2549 else
2553 {
2556 {
2559 /* Punt on pseudos set multiple times. */
2564 else
2567 {
2569 internal_arg_pointer_exp_state.cache
2572 }
2573 }
2577 }
2580 }
2582 /* Compute whether RTL is based on crtl->args.internal_arg_pointer. Return
2583 NULL_RTX if RTL isn't based on it, a CONST_INT offset if RTL is based on
2584 it with fixed offset, or PC if this is with variable or unknown offset.
2585 TOPLEVEL is true if the function is invoked at the topmost level. */
2587 static rtx
2589 {
2599 poly_int64 offset;
2601 {
2606 }
2608 /* When called at the topmost level, scan pseudo assignments in between the
2609 last scanned instruction in the tail call sequence and the latest insn
2610 in that sequence. */
2615 {
2621 }
2625 {
2631 }
2634 }
2636 /* Return true if SIZE bytes starting from address ADDR might overlap an
2637 already-clobbered argument area. This function is used to determine
2638 if we should give up a sibcall. */
2640 static bool
2642 {
2643 poly_int64 i;
2645 rtx val;
2661 else
2667 /* We can ignore any references to the function's pretend args,
2668 which at this point would manifest as negative values of I. */
2685 }
2687 /* Do the register loads required for any wholly-register parms or any
2688 parms which are passed both on the stack and in a register. Their
2689 expressions were already evaluated.
2691 Mark all register-parms as living through the call, putting these USE
2692 insns in the CALL_INSN_FUNCTION_USAGE field.
2694 When IS_SIBCALL, perform the check_sibcall_argument_overlap
2695 checking, setting *SIBCALL_FAILURE if appropriate. */
2697 static void
2701 {
2705 {
2709 {
2715 /* Set non-negative if we must move a word at a time, even if
2716 just one word (e.g, partial == 4 && mode == DFmode). Set
2717 to -1 if we just use a normal move insn. This value can be
2718 zero if the argument is a zero size structure. */
2721 ;
2723 {
2726 }
2728 {
2729 /* Variable-sized parameters should be described by a
2730 PARALLEL instead. */
2735 }
2736 else
2739 /* Handle calls that pass values in multiple non-contiguous
2740 locations. The Irix 6 ABI has examples of this. */
2745 /* If simple case, just do move. If normal partial, store_one_arg
2746 has already loaded the register for us. In all other cases,
2747 load the register(s) from memory. */
2750 {
2752 #ifdef BLOCK_REG_PADDING
2753 /* Handle case where we have a value that needs shifting
2754 up to the msb. eg. a QImode value and we're padding
2755 upward on a BYTES_BIG_ENDIAN machine. */
2758 {
2761 {
2762 rtx x;
2763 poly_int64 shift
2766 /* Assigning REG here rather than a temp makes
2767 CALL_FUSAGE report the whole reg as used.
2768 Strictly speaking, the call only uses SIZE
2769 bytes at the msb end, but it doesn't seem worth
2770 generating rtl to say that. */
2776 }
2777 }
2778 #endif
2779 }
2781 /* If we have pre-computed the values to put in the registers in
2782 the case of non-aligned structures, copy them in now. */
2790 {
2791 /* SIZE and CONST_SIZE are 0 for partial arguments and
2792 the size of a BLKmode type otherwise. */
2796 /* Check for overlap with already clobbered argument area,
2797 providing that this has non-zero size. */
2800 && (mem_might_overlap_already_clobbered_arg_p
2807 else
2808 {
2817 NULL);
2823 }
2825 /* Handle a BLKmode that needs shifting. */
2827 #ifdef BLOCK_REG_PADDING
2829 #else
2830 && BYTES_BIG_ENDIAN
2831 #endif
2832 )
2833 {
2838 rtx x;
2843 }
2844 }
2846 /* When a parameter is a block, and perhaps in other cases, it is
2847 possible that it did a load from an argument slot that was
2848 already clobbered. */
2853 /* Handle calls that pass values in multiple non-contiguous
2854 locations. The Irix 6 ABI has examples of this. */
2862 }
2863 }
2864 }
2866 /* We need to pop PENDING_STACK_ADJUST bytes. But, if the arguments
2867 wouldn't fill up an even multiple of PREFERRED_UNIT_STACK_BOUNDARY
2868 bytes, then we would need to push some additional bytes to pad the
2869 arguments. So, we try to compute an adjust to the stack pointer for an
2870 amount that will leave the stack under-aligned by UNADJUSTED_ARGS_SIZE
2871 bytes. Then, when the arguments are pushed the stack will be perfectly
2872 aligned.
2874 Return true if this optimization is possible, storing the adjustment
2875 in ADJUSTMENT_OUT and setting ARGS_SIZE->CONSTANT to the number of
2876 bytes that should be popped after the call. */
2878 static bool
2880 poly_int64 unadjusted_args_size,
2883 {
2884 /* The number of bytes to pop so that the stack will be
2885 under-aligned by UNADJUSTED_ARGS_SIZE bytes. */
2886 poly_int64 adjustment;
2887 /* The alignment of the stack after the arguments are pushed, if we
2888 just pushed the arguments without adjust the stack here. */
2892 preferred_unit_stack_boundary,
2896 /* We want to get rid of as many of the PENDING_STACK_ADJUST bytes
2897 as possible -- leaving just enough left to cancel out the
2898 UNADJUSTED_ALIGNMENT. In other words, we want to ensure that the
2899 PENDING_STACK_ADJUST is non-negative, and congruent to
2900 -UNADJUSTED_ALIGNMENT modulo the PREFERRED_UNIT_STACK_BOUNDARY. */
2902 /* Begin by trying to pop all the bytes. */
2905 preferred_unit_stack_boundary,
2910 /* Push enough additional bytes that the stack will be aligned
2911 after the arguments are pushed. */
2915 /* We need to know whether the adjusted argument size
2916 (UNADJUSTED_ARGS_SIZE - ADJUSTMENT) constitutes an allocation
2917 or a deallocation. */
2921 /* Now, sets ARGS_SIZE->CONSTANT so that we pop the right number of
2922 bytes after the call. The right number is the entire
2923 PENDING_STACK_ADJUST less our ADJUSTMENT plus the amount required
2924 by the arguments in the first place. */
2925 args_size->constant
2930 }
2932 /* Scan X expression if it does not dereference any argument slots
2933 we already clobbered by tail call arguments (as noted in stored_args_map
2934 bitmap).
2935 Return nonzero if X expression dereferences such argument slots,
2936 zero otherwise. */
2938 static int
2940 {
2941 RTX_CODE code;
2950 /* We need not check the operands of the CALL expression itself. */
2958 /* Scan all subexpressions. */
2961 {
2963 {
2966 }
2968 {
2972 }
2973 }
2975 }
2977 /* Scan sequence after INSN if it does not dereference any argument slots
2978 we already clobbered by tail call arguments (as noted in stored_args_map
2979 bitmap). If MARK_STORED_ARGS_MAP, add stack slots for ARG to
2980 stored_args_map bitmap afterwards (when ARG is a register MARK_STORED_ARGS_MAP
2981 should be 0). Return nonzero if sequence after INSN dereferences such argument
2982 slots, zero otherwise. */
2984 static int
2987 {
2993 else
3002 {
3005 else
3013 else
3015 }
3017 }
3019 /* Given that a function returns a value of mode MODE at the most
3020 significant end of hard register VALUE, shift VALUE left or right
3021 as specified by LEFT_P. Return true if some action was needed. */
3023 bool
3025 {
3033 /* Use ashr rather than lshr for right shifts. This is for the benefit
3034 of the MIPS port, which requires SImode values to be sign-extended
3035 when stored in 64-bit registers. */
3041 }
3043 /* If X is a likely-spilled register value, copy it to a pseudo
3044 register and return that register. Return X otherwise. */
3046 static rtx
3048 {
3049 rtx new_rtx;
3054 {
3055 /* Make sure that we generate a REG rather than a CONCAT.
3056 Moves into CONCATs can need nontrivial instructions,
3057 and the whole point of this function is to avoid
3058 using the hard register directly in such a situation. */
3064 }
3066 }
3068 /* Helper function for expand_call.
3069 Return false is EXP is not implementable as a sibling call. */
3071 static bool
3073 rtx structure_value_addr,
3074 tree funtype,
3076 tree fndecl,
3078 tree addr,
3080 {
3082 {
3083 maybe_complain_about_tail_call
3085 "machine description does not have"
3088 }
3090 /* Doing sibling call optimization needs some work, since
3091 structure_value_addr can be allocated on the stack.
3092 It does not seem worth the effort since few optimizable
3093 sibling calls will return a structure. */
3095 {
3098 }
3100 #ifdef REG_PARM_STACK_SPACE
3101 /* If outgoing reg parm stack space changes, we can not do sibcall. */
3105 {
3107 "inconsistent size of stack space"
3108 " allocated for arguments which are"
3111 }
3112 #endif
3114 /* Check whether the target is able to optimize the call
3115 into a sibcall. */
3117 {
3119 "target is not able to optimize the"
3122 }
3124 /* Functions that do not return exactly once may not be sibcall
3125 optimized. */
3127 {
3130 }
3132 {
3135 }
3138 {
3141 }
3143 /* If the called function is nested in the current one, it might access
3144 some of the caller's arguments, but could clobber them beforehand if
3145 the argument areas are shared. */
3147 {
3150 }
3152 /* If this function requires more stack slots than the current
3153 function, we cannot change it into a sibling call.
3154 crtl->args.pretend_args_size is not part of the
3155 stack allocated by our caller. */
3158 {
3160 "callee required more stack slots"
3163 }
3165 /* If the callee pops its own arguments, then it must pop exactly
3166 the same number of arguments as the current function. */
3170 TREE_TYPE
3173 {
3175 "inconsistent number of"
3178 }
3181 {
3185 }
3187 /* All checks passed. */
3189 }
3191 /* Generate all the code for a CALL_EXPR exp
3192 and return an rtx for its value.
3193 Store the value in TARGET (specified as an rtx) if convenient.
3194 If the value is stored in TARGET then TARGET is returned.
3195 If IGNORE is nonzero, then we ignore the value of the function call. */
3197 rtx
3199 {
3200 /* Nonzero if we are currently expanding a call. */
3203 /* RTX for the function to be called. */
3204 rtx funexp;
3205 /* Sequence of insns to perform a normal "call". */
3207 /* Sequence of insns to perform a tail "call". */
3209 /* Data type of the function. */
3210 tree funtype;
3211 tree type_arg_types;
3212 tree rettype;
3213 /* Declaration of the function being called,
3214 or 0 if the function is computed (not known by name). */
3216 /* The type of the function being called. */
3217 tree fntype;
3222 /* Register in which non-BLKmode value will be returned,
3223 or 0 if no value or if value is BLKmode. */
3224 rtx valreg;
3225 /* Address where we should return a BLKmode value;
3226 0 if value not BLKmode. */
3228 /* Nonzero if that address is being passed by treating it as
3229 an extra, implicit first parameter. Otherwise,
3230 it is passed by being copied directly into struct_value_rtx. */
3232 /* Holds the value of implicit argument for the struct value. */
3234 /* Size of aggregate value wanted, or zero if none wanted
3235 or if we are using the non-reentrant PCC calling convention
3236 or expecting the value in registers. */
3238 /* Nonzero if called function returns an aggregate in memory PCC style,
3239 by returning the address of where to find it. */
3243 /* Number of actual parameters in this call, including struct value addr. */
3245 /* Number of named args. Args after this are anonymous ones
3246 and they must all go on the stack. */
3248 /* Number of complex actual arguments that need to be split. */
3251 /* Vector of information about each argument.
3252 Arguments are numbered in the order they will be pushed,
3253 not the order they are written. */
3256 /* Total size in bytes of all the stack-parms scanned so far. */
3259 /* Size of arguments before any adjustments (such as rounding). */
3260 poly_int64 unadjusted_args_size;
3261 /* Data on reg parms scanned so far. */
3262 CUMULATIVE_ARGS args_so_far_v;
3263 cumulative_args_t args_so_far;
3264 /* Nonzero if a reg parm has been scanned. */
3266 /* Nonzero if this is an indirect function call. */
3268 /* Nonzero if we must avoid push-insns in the args for this call.
3269 If stack space is allocated for register parameters, but not by the
3270 caller, then it is preallocated in the fixed part of the stack frame.
3271 So the entire argument block must then be preallocated (i.e., we
3272 ignore PUSH_ROUNDING in that case). */
3276 /* Size of the stack reserved for parameter registers. */
3279 /* Address of space preallocated for stack parms
3280 (on machines that lack push insns), or 0 if space not preallocated. */
3283 /* Mask of ECF_ and ERF_ flags. */
3286 #ifdef REG_PARM_STACK_SPACE
3287 /* Define the boundary of the register parm stack space that needs to be
3288 saved, if any. */
3291 #endif
3298 poly_int64 old_stack_allocated;
3300 /* State variables to track stack modifications. */
3306 /* Some stack pointer alterations we make are performed via
3307 allocate_dynamic_stack_space. This modifies the stack_pointer_delta,
3308 which we then also need to save/restore along the way. */
3311 rtx call_fusage;
3314 /* The alignment of the stack, in bits. */
3316 /* The alignment of the stack, in bytes. */
3318 /* The static chain value to use for this call. */
3319 rtx static_chain_value;
3320 /* See if this is "nothrow" function call. */
3324 /* See if we can find a DECL-node for the actual function, and get the
3325 function attributes (flags) from the function decl or type node. */
3328 {
3332 }
3333 else
3334 {
3339 }
3344 /* Warn if this value is an aggregate type,
3345 regardless of which calling convention we are using for it. */
3349 /* If the result of a non looping pure or const function call is
3350 ignored (or void), and none of its arguments are volatile, we can
3351 avoid expanding the call and just evaluate the arguments for
3352 side-effects. */
3357 {
3359 tree arg;
3360 call_expr_arg_iterator iter;
3364 {
3367 }
3370 {
3374 }
3375 }
3377 #ifdef REG_PARM_STACK_SPACE
3379 #endif
3385 /* Set up a place to return a structure. */
3387 /* Cater to broken compilers. */
3389 {
3390 /* This call returns a big structure. */
3393 #ifdef PCC_STATIC_STRUCT_RETURN
3394 {
3396 }
3398 {
3402 /* Even if it is semantically safe to use the target as the return
3403 slot, it may be not sufficiently aligned for the return type. */
3405 && target
3407 /* If rettype is addressable, we may not create a temporary.
3408 If target is properly aligned at runtime and the compiler
3409 just doesn't know about it, it will work fine, otherwise it
3410 will be UB. */
3416 else
3417 {
3418 /* For variable-sized objects, we must be called with a target
3419 specified. If we were to allocate space on the stack here,
3420 we would have no way of knowing when to free it. */
3424 }
3425 }
3427 }
3429 /* Figure out the amount to which the stack should be aligned. */
3432 {
3434 /* Without automatic stack alignment, we can't increase preferred
3435 stack boundary. With automatic stack alignment, it is
3436 unnecessary since unless we can guarantee that all callers will
3437 align the outgoing stack properly, callee has to align its
3438 stack anyway. */
3443 }
3445 /* Operand 0 is a pointer-to-function; get the type of the function. */
3450 /* Count whether there are actual complex arguments that need to be split
3451 into their real and imaginary parts. Munge the type_arg_types
3452 appropriately here as well. */
3454 {
3455 call_expr_arg_iterator iter;
3456 tree arg;
3458 {
3462 num_complex_actuals++;
3463 }
3465 }
3466 else
3472 /* If struct_value_rtx is 0, it means pass the address
3473 as if it were an extra parameter. Put the argument expression
3474 in structure_value_addr_value. */
3476 {
3477 /* If structure_value_addr is a REG other than
3478 virtual_outgoing_args_rtx, we can use always use it. If it
3479 is not a REG, we must always copy it into a register.
3480 If it is virtual_outgoing_args_rtx, we must copy it to another
3481 register in some cases. */
3483 || (ACCUMULATE_OUTGOING_ARGS
3484 && stack_arg_under_construction
3490 structure_value_addr_value =
3493 }
3495 /* Count the arguments and set NUM_ACTUALS. */
3496 num_actuals =
3499 /* Compute number of named args.
3500 First, do a raw count of the args for INIT_CUMULATIVE_ARGS. */
3503 n_named_args
3505 /* Count the struct value address, if it is passed as a parm. */
3507 else
3508 /* If we know nothing, treat all args as named. */
3511 /* Start updating where the next arg would go.
3513 On some machines (such as the PA) indirect calls have a different
3514 calling convention than normal calls. The fourth argument in
3515 INIT_CUMULATIVE_ARGS tells the backend if this is an indirect call
3516 or not. */
3520 /* Now possibly adjust the number of named args.
3521 Normally, don't include the last named arg if anonymous args follow.
3522 We do include the last named arg if
3523 targetm.calls.strict_argument_naming() returns nonzero.
3524 (If no anonymous args follow, the result of list_length is actually
3525 one too large. This is harmless.)
3527 If targetm.calls.pretend_outgoing_varargs_named() returns
3528 nonzero, and targetm.calls.strict_argument_naming() returns zero,
3529 this machine will be able to place unnamed args that were passed
3530 in registers into the stack. So treat all args as named. This
3531 allows the insns emitting for a specific argument list to be
3532 independent of the function declaration.
3534 If targetm.calls.pretend_outgoing_varargs_named() returns zero,
3535 we do not have any reliable way to pass unnamed args in
3536 registers, so we must force them into memory. */
3540 ;
3543 /* Don't include the last named arg. */
3545 else
3546 /* Treat all args as named. */
3549 /* Make a vector to hold all the information about each arg. */
3552 /* Build up entries in the ARGS array, compute the size of the
3553 arguments into ARGS_SIZE, etc. */
3565 /* Now make final decision about preallocating stack space. */
3570 /* If the structure value address will reference the stack pointer, we
3571 must stabilize it. We don't need to do this if we know that we are
3572 not going to adjust the stack pointer in processing this call. */
3577 structure_value_addr))
3579 || (!ACCUMULATE_OUTGOING_ARGS
3583 /* Tail calls can make things harder to debug, and we've traditionally
3584 pushed these optimizations into -O2. Don't try if we're already
3585 expanding a call, as that means we're an argument. Don't try if
3586 there's cleanups, as we know there's code to follow the call. */
3589 || !flag_optimize_sibling_calls
3594 /* If the user has marked the function as requiring tail-call
3595 optimization, attempt it. */
3599 /* Rest of purposes for tail call optimizations to fail. */
3602 structure_value_addr,
3603 funtype,
3604 reg_parm_stack_space,
3605 fndecl,
3608 /* Check if caller and callee disagree in promotion of function
3609 return value. */
3611 {
3621 caller_promoted_mode
3625 callee_promoted_mode
3635 {
3638 "caller and callee disagree in"
3639 " promotion of function"
3641 }
3642 }
3644 /* Ensure current function's preferred stack boundary is at least
3645 what we need. Stack alignment may also increase preferred stack
3646 boundary. */
3649 else
3654 /* We want to make two insn chains; one for a sibling call, the other
3655 for a normal call. We will select one of the two chains after
3656 initial RTL generation is complete. */
3658 {
3660 /* We want to emit any pending stack adjustments before the tail
3661 recursion "call". That way we know any adjustment after the tail
3662 recursion call can be ignored if we indeed use the tail
3663 call expansion. */
3664 saved_pending_stack_adjust save;
3666 rtx next_arg_reg;
3669 {
3670 /* State variables we need to save and restore between
3671 iterations. */
3673 }
3676 else
3679 /* Other state variables that we must reinitialize each time
3680 through the loop (that are not initialized by the loop itself). */
3684 /* Start a new sequence for the normal call case.
3686 From this point on, if the sibling call fails, we want to set
3687 sibcall_failure instead of continuing the loop. */
3690 /* Don't let pending stack adjusts add up to too much.
3691 Also, do all pending adjustments now if there is any chance
3692 this might be a call to alloca or if we are expanding a sibling
3693 call sequence.
3694 Also do the adjustments before a throwing call, otherwise
3695 exception handling can fail; PR 19225. */
3704 /* Precompute any arguments as needed. */
3708 /* Now we are about to start emitting insns that can be deleted
3709 if a libcall is deleted. */
3719 /* Compute the actual size of the argument block required. The variable
3720 and constant sizes must be combined, the size may have to be rounded,
3721 and there may be a minimum required size. When generating a sibcall
3722 pattern, do not round up, since we'll be re-using whatever space our
3723 caller provided. */
3724 unadjusted_args_size
3733 /* The argument block when performing a sibling call is the
3734 incoming argument block. */
3736 {
3739 argblock
3741 else
3742 argblock
3749 }
3751 /* If we have no actual push instructions, or shouldn't use them,
3752 make space for all args right now. */
3754 {
3756 {
3761 /* stack_arg_under_construction says whether a stack arg is
3762 being constructed at the old stack level. Pushing the stack
3763 gets a clean outgoing argument block. */
3766 }
3770 }
3771 else
3772 {
3773 /* Note that we must go through the motions of allocating an argument
3774 block even if the size is zero because we may be storing args
3775 in the area reserved for register arguments, which may be part of
3776 the stack frame. */
3780 /* Store the maximum argument space used. It will be pushed by
3781 the prologue (if ACCUMULATE_OUTGOING_ARGS, or stack overflow
3782 checking). */
3785 needed);
3788 {
3790 {
3791 /* Since the stack pointer will never be pushed, it is
3792 possible for the evaluation of a parm to clobber
3793 something we have already written to the stack.
3794 Since most function calls on RISC machines do not use
3795 the stack, this is uncommon, but must work correctly.
3797 Therefore, we save any area of the stack that was already
3798 written and that we are using. Here we set up to do this
3799 by making a new stack usage map from the old one. The
3800 actual save will be done by store_one_arg.
3802 Another approach might be to try to reorder the argument
3803 evaluations to avoid this conflicting stack usage. */
3805 /* Since we will be writing into the entire argument area,
3806 the map must be allocated for its entire size, not just
3807 the part that is the responsibility of the caller. */
3815 /* For polynomial sizes, this is the maximum possible
3816 size needed for arguments with a constant size
3817 and offset. */
3819 highest_outgoing_arg_in_use
3828 initial_highest_arg_in_use);
3832 (highest_outgoing_arg_in_use
3836 /* The address of the outgoing argument list must not be
3837 copied to a register here, because argblock would be left
3838 pointing to the wrong place after the call to
3839 allocate_dynamic_stack_space below. */
3842 }
3843 else
3844 {
3845 /* Try to reuse some or all of the pending_stack_adjust
3846 to get this space. */
3848 && (combine_pending_stack_adjustment_and_call
3850 unadjusted_args_size,
3852 preferred_unit_stack_boundary)))
3853 {
3854 /* combine_pending_stack_adjustment_and_call computes
3855 an adjustment before the arguments are allocated.
3856 Account for them and see whether or not the stack
3857 needs to go up or down. */
3860 /* Checked by
3861 combine_pending_stack_adjustment_and_call. */
3864 {
3865 /* We're releasing stack space. */
3866 /* ??? We can avoid any adjustment at all if we're
3867 already aligned. FIXME. */
3871 }
3872 else
3873 /* We need to allocate space. We'll do that in
3874 push_block below. */
3876 }
3878 /* Special case this because overhead of `push_block' in
3879 this case is non-trivial. */
3882 else
3883 {
3888 }
3890 /* We only really need to call `copy_to_reg' in the case
3891 where push insns are going to be used to pass ARGBLOCK
3892 to a function call in ARGS. In that case, the stack
3893 pointer changes value from the allocation point to the
3894 call point, and hence the value of
3895 VIRTUAL_OUTGOING_ARGS_RTX changes as well. But might
3896 as well always do it. */
3898 }
3899 }
3900 }
3903 {
3904 /* The save/restore code in store_one_arg handles all
3905 cases except one: a constructor call (including a C
3906 function returning a BLKmode struct) to initialize
3907 an argument. */
3909 {
3910 rtx push_size
3911 = (gen_int_mode
3917 {
3922 /* stack_arg_under_construction says whether a stack
3923 arg is being constructed at the old stack level.
3924 Pushing the stack gets a clean outgoing argument
3925 block. */
3926 old_stack_arg_under_construction
3929 /* Make a new map for the new argument list. */
3935 }
3936 /* We can pass TRUE as the 4th argument because we just
3937 saved the stack pointer and will restore it right after
3938 the call. */
3941 }
3943 /* If argument evaluation might modify the stack pointer,
3944 copy the address of the argument list to a register. */
3947 {
3950 }
3951 }
3955 /* Stack is properly aligned, pops can't safely be deferred during
3956 the evaluation of the arguments. */
3957 NO_DEFER_POP;
3959 /* Precompute all register parameters. It isn't safe to compute
3960 anything once we have started filling any specific hard regs.
3961 TLS symbols sometimes need a call to resolve. Precompute
3962 register parameters before any stack pointer manipulation
3963 to avoid unaligned stack in the called function. */
3966 OK_DEFER_POP;
3968 /* Perform stack alignment before the first push (the last arg). */
3972 {
3973 /* When the stack adjustment is pending, we get better code
3974 by combining the adjustments. */
3976 && ! inhibit_defer_pop
3977 && (combine_pending_stack_adjustment_and_call
3979 unadjusted_args_size,
3981 preferred_unit_stack_boundary)))
3986 Pmode));
3987 }
3988 /* Now that the stack is properly aligned, pops can't safely
3989 be deferred during the evaluation of the arguments. */
3990 NO_DEFER_POP;
3992 /* Record the maximum pushed stack space size. We need to delay
3993 doing it this far to take into account the optimization done
3994 by combine_pending_stack_adjustment_and_call. */
3996 && !ACCUMULATE_OUTGOING_ARGS
3997 && pass
3999 {
4002 current_function_pushed_stack_size
4004 }
4010 else
4013 #ifdef REG_PARM_STACK_SPACE
4014 /* Save the fixed argument area if it's part of the caller's frame and
4015 is clobbered by argument setup for this call. */
4019 #endif
4021 /* Now store (and compute if necessary) all non-register parms.
4022 These come before register parms, since they can require block-moves,
4023 which could clobber the registers used for register parms.
4024 Parms which have partial registers are not stored here,
4025 but we do preallocate space here if they want that. */
4028 {
4030 {
4033 /* We don't allow passing huge (> 2^30 B) arguments
4034 by value. It would cause an overflow later on. */
4037 {
4040 }
4044 reg_parm_stack_space)
4049 }
4052 call_fusage
4055 call_fusage);
4056 }
4058 /* If we have a parm that is passed in registers but not in memory
4059 and whose alignment does not permit a direct copy into registers,
4060 make a group of pseudos that correspond to each register that we
4061 will later fill. */
4065 /* Now store any partially-in-registers parm.
4066 This is the last place a block-move can happen. */
4070 {
4073 /* On targets with weird calling conventions (e.g. PA) it's
4074 hard to ensure that all cases of argument overlap between
4075 stack and registers work. Play it safe and bail out. */
4077 {
4080 }
4084 reg_parm_stack_space)
4089 }
4094 {
4097 }
4101 /* Figure out the register where the value, if any, will come back. */
4105 {
4109 else
4113 /* If VALREG is a PARALLEL whose first member has a zero
4114 offset, use that. This is for targets such as m68k that
4115 return the same value in multiple places. */
4117 {
4124 }
4125 }
4127 /* If register arguments require space on the stack and stack space
4128 was not preallocated, allocate stack space here for arguments
4129 passed in registers. */
4131 && !ACCUMULATE_OUTGOING_ARGS
4135 /* Pass the function the address in which to return a
4136 structure value. */
4138 {
4139 structure_value_addr
4144 NULL_RTX)));
4148 }
4158 /* Save a pointer to the last insn before the call, so that we can
4159 later safely search backwards to find the CALL_INSN. */
4162 /* Set up next argument register. For sibling calls on machines
4163 with register windows this should be the incoming register. */
4166 VOIDmode,
4167 void_type_node,
4169 else
4175 {
4181 && valreg
4184 call_fusage
4187 call_fusage);
4188 }
4189 /* All arguments and registers used for the call must be set up by
4190 now! */
4192 /* Stack must be properly aligned now. */
4195 preferred_unit_stack_boundary));
4197 /* Generate the actual call instruction. */
4204 {
4208 {
4212 }
4215 }
4217 /* If the call setup or the call itself overlaps with anything
4218 of the argument setup we probably clobbered our call address.
4219 In that case we can't do sibcalls. */
4224 /* If a non-BLKmode value is returned at the most significant end
4225 of a register, shift the register right by the appropriate amount
4226 and update VALREG accordingly. BLKmode values are handled by the
4227 group load/store machinery below. */
4229 && !pcc_struct_value
4234 {
4238 }
4241 {
4245 /* The return value from a malloc-like function is a pointer. */
4251 /* The return value from a malloc-like function can not alias
4252 anything else. */
4256 /* Write out the sequence. */
4261 }
4263 /* For calls to `setjmp', etc., inform
4264 function.c:setjmp_warnings that it should complain if
4265 nonvolatile values are live. For functions that cannot
4266 return, inform flow that control does not fall through. */
4269 {
4270 /* The barrier must be emitted
4271 immediately after the CALL_INSN. Some ports emit more
4272 than just a CALL_INSN above, so we must search for it here. */
4276 {
4278 /* There was no CALL_INSN? */
4280 }
4284 /* Stack adjustments after a noreturn call are dead code.
4285 However when NO_DEFER_POP is in effect, we must preserve
4286 stack_pointer_delta. */
4288 {
4291 }
4292 }
4294 /* If value type not void, return an rtx for the value. */
4300 {
4302 {
4303 target
4306 structure_value_addr));
4308 }
4309 }
4311 {
4312 /* This is the special C++ case where we need to
4313 know what the true target was. We take care to
4314 never use this value more than once in one expression. */
4318 }
4319 /* Handle calls that return values in multiple non-contiguous locations.
4320 The Irix 6 ABI has examples of this. */
4322 {
4326 ;
4328 /* Handle the result of a emit_group_move_into_temps
4329 call in the previous pass. */
4331 else
4334 }
4338 {
4341 /* We have to copy a return value in a CLASS_LIKELY_SPILLED hard
4342 reg to a plain register. */
4346 /* If TARGET is a MEM in the argument area, and we have
4347 saved part of the argument area, then we can't store
4348 directly into TARGET as it may get overwritten when we
4349 restore the argument save area below. Don't work too
4350 hard though and simply force TARGET to a register if it
4351 is a MEM; the optimizer is quite likely to sort it out. */
4355 {
4358 }
4362 else
4363 {
4364 /* TARGET and VALREG cannot be equal at this point
4365 because the latter would not have
4366 REG_FUNCTION_VALUE_P true, while the former would if
4367 it were referring to the same register.
4369 If they refer to the same register, this move will be
4370 a no-op, except when function inlining is being
4371 done. */
4374 /* If we are setting a MEM, this code must be executed.
4375 Since it is emitted after the call insn, sibcall
4376 optimization cannot be performed in that case. */
4379 }
4380 }
4381 else
4384 /* If we promoted this return value, make the proper SUBREG.
4385 TARGET might be const0_rtx here, so be careful. */
4389 {
4392 machine_mode pmode;
4394 /* Ensure we promote as expected, and get the new unsignedness. */
4404 }
4406 /* If size of args is variable or this was a constructor call for a stack
4407 argument, restore saved stack-pointer value. */
4410 {
4425 }
4427 {
4428 #ifdef REG_PARM_STACK_SPACE
4432 #endif
4434 /* If we saved any argument areas, restore them. */
4437 {
4439 rtx stack_area
4446 else
4448 (gen_int_mode
4450 BLOCK_OP_CALL_PARM);
4451 }
4456 }
4458 /* If this was alloca, record the new stack level. */
4462 /* Free up storage we no longer need. */
4472 {
4475 /* Restore the pending stack adjustment now that we have
4476 finished generating the sibling call sequence. */
4480 /* Prepare arg structure for next iteration. */
4482 {
4486 }
4491 }
4492 else
4493 {
4496 /* Verify that we've deallocated all the stack we used. */
4499 stack_pointer_delta
4501 }
4503 /* If something prevents making this a sibling call,
4504 zero out the sequence. */
4507 else
4509 }
4511 /* If tail call production succeeded, we need to remove REG_EQUIV notes on
4512 arguments too, as argument area is now clobbered by the call. */
4514 {
4517 }
4518 else
4519 {
4522 /* Ideally we'd emit a message for all of the ways that it could
4523 have failed. */
4525 }
4527 currently_expanding_call--;
4532 }
4534 /* A sibling call sequence invalidates any REG_EQUIV notes made for
4535 this function's incoming arguments.
4537 At the start of RTL generation we know the only REG_EQUIV notes
4538 in the rtl chain are those for incoming arguments, so we can look
4539 for REG_EQUIV notes between the start of the function and the
4540 NOTE_INSN_FUNCTION_BEG.
4542 This is (slight) overkill. We could keep track of the highest
4543 argument we clobber and be more selective in removing notes, but it
4544 does not seem to be worth the effort. */
4546 void
4548 {
4552 {
4553 rtx note;
4555 /* There are never REG_EQUIV notes for the incoming arguments
4556 after the NOTE_INSN_FUNCTION_BEG note, so stop if we see it. */
4566 }
4567 }
4569 /* Traverse a list of TYPES and expand all complex types into their
4570 components. */
4571 static tree
4573 {
4574 tree p;
4576 /* Before allocating memory, check for the common case of no complex. */
4578 {
4583 }
4586 found:
4590 {
4595 {
4598 /* Rewrite complex type with component type. */
4602 /* Add another component type for the imaginary part. */
4607 /* Skip the newly created node. */
4609 }
4610 }
4613 }
4614 \f
4615 /* Output a library call to function ORGFUN (a SYMBOL_REF rtx)
4616 for a value of mode OUTMODE,
4617 with NARGS different arguments, passed as ARGS.
4618 Store the return value if RETVAL is nonzero: store it in VALUE if
4619 VALUE is nonnull, otherwise pick a convenient location. In either
4620 case return the location of the stored value.
4622 FN_TYPE should be LCT_NORMAL for `normal' calls, LCT_CONST for
4623 `const' calls, LCT_PURE for `pure' calls, or another LCT_ value for
4624 other types of library calls. */
4626 rtx
4630 {
4631 /* Total size in bytes of all the stack-parms scanned so far. */
4633 /* Size of arguments before any adjustments (such as rounding). */
4636 rtx fun;
4637 /* Todo, choose the correct decl type of orgfun. Sadly this information
4638 isn't present here, so we default to native calling abi here. */
4643 CUMULATIVE_ARGS args_so_far_v;
4644 cumulative_args_t args_so_far;
4645 struct arg
4646 {
4647 rtx value;
4648 machine_mode mode;
4649 rtx reg;
4652 rtx save_area;
4653 };
4658 rtx valreg;
4663 poly_int64 needed;
4668 #ifdef REG_PARM_STACK_SPACE
4669 /* Define the boundary of the register parm stack space that needs to be
4670 save, if any. */
4673 #endif
4675 /* Size of the stack reserved for parameter registers. */
4683 #ifdef REG_PARM_STACK_SPACE
4685 #endif
4687 /* By default, library functions cannot throw. */
4691 {
4709 }
4712 /* Ensure current function's preferred stack boundary is at least
4713 what we need. */
4717 /* If this kind of value comes back in memory,
4718 decide where in memory it should come back. */
4720 {
4723 {
4724 #ifdef PCC_STATIC_STRUCT_RETURN
4725 rtx pointer_reg
4735 else
4737 #endif
4738 /* This call returns a big structure. */
4740 }
4741 }
4742 else
4745 /* ??? Unfinished: must pass the memory address as an argument. */
4747 /* Copy all the libcall-arguments out of the varargs data
4748 and into a vector ARGVEC.
4750 Compute how to pass each argument. We only support a very small subset
4751 of the full argument passing conventions to limit complexity here since
4752 library functions shouldn't have many args. */
4757 #ifdef INIT_CUMULATIVE_LIBCALL_ARGS
4759 #else
4761 #endif
4771 /* If there's a structure value address to be passed,
4772 either pass it in the special place, or pass it as an extra argument. */
4774 {
4777 nargs++;
4779 /* Make sure it is a reasonable operand for a move or push insn. */
4795 #ifdef STACK_PARMS_IN_REG_PARM_AREA
4797 #else
4799 #endif
4809 count++;
4810 }
4813 {
4818 /* We cannot convert the arg value to the mode the library wants here;
4819 must do it earlier where we know the signedness of the arg. */
4823 /* Make sure it is a reasonable operand for a move or push insn. */
4829 {
4830 rtx slot;
4831 int must_copy
4834 /* If this was a CONST function, it is now PURE since it now
4835 reads memory. */
4837 {
4840 }
4843 {
4848 }
4849 else
4850 {
4854 }
4858 call_fusage);
4862 slot),
4863 call_fusage);
4867 }
4881 {
4883 #ifdef STACK_PARMS_IN_REG_PARM_AREA
4885 #else
4887 #endif
4892 }
4893 #ifdef BLOCK_REG_PADDING
4894 else
4895 /* The argument is passed entirely in registers. See at which
4896 end it should be padded. */
4900 #endif
4903 }
4905 /* If this machine requires an external definition for library
4906 functions, write one out. */
4912 STACK_BYTES)
4916 reg_parm_stack_space);
4925 {
4927 current_function_pushed_stack_size
4929 }
4932 {
4933 /* Since the stack pointer will never be pushed, it is possible for
4934 the evaluation of a parm to clobber something we have already
4935 written to the stack. Since most function calls on RISC machines
4936 do not use the stack, this is uncommon, but must work correctly.
4938 Therefore, we save any area of the stack that was already written
4939 and that we are using. Here we set up to do this by making a new
4940 stack usage map from the old one.
4942 Another approach might be to try to reorder the argument
4943 evaluations to avoid this conflicting stack usage. */
4947 /* Since we will be writing into the entire argument area, the
4948 map must be allocated for its entire size, not just the part that
4949 is the responsibility of the caller. */
4957 /* For polynomial sizes, this is the maximum possible size needed
4958 for arguments with a constant size and offset. */
4961 const_limit);
4968 initial_highest_arg_in_use);
4975 /* We must be careful to use virtual regs before they're instantiated,
4976 and real regs afterwards. Loop optimization, for example, can create
4977 new libcalls after we've instantiated the virtual regs, and if we
4978 use virtuals anyway, they won't match the rtl patterns. */
4982 STACK_POINTER_OFFSET);
4983 else
4985 }
4986 else
4987 {
4990 }
4992 /* We push args individually in reverse order, perform stack alignment
4993 before the first push (the last arg). */
4997 Pmode));
5001 #ifdef REG_PARM_STACK_SPACE
5003 {
5004 /* The argument list is the property of the called routine and it
5005 may clobber it. If the fixed area has been used for previous
5006 parameters, we must save and restore it. */
5009 }
5010 #endif
5012 /* When expanding a normal call, args are stored in push order,
5013 which is the reverse of what we have here. */
5017 {
5020 }
5024 /* Push the args that need to be pushed. */
5028 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
5029 are to be pushed. */
5031 {
5040 {
5041 rtx use;
5044 {
5045 /* If this is being stored into a pre-allocated, fixed-size,
5046 stack area, save any previous data at that location. */
5049 {
5050 /* stack_slot is negative, but we want to index stack_usage_map
5051 with positive values. */
5054 }
5055 else
5056 {
5059 }
5062 reg_parm_stack_space))
5063 {
5064 /* We need to make a save area. */
5065 poly_uint64 size
5067 machine_mode save_mode
5069 rtx adr
5072 rtx stack_area
5076 {
5080 );
5084 stack_area,
5085 (gen_int_mode
5087 Pmode)),
5088 BLOCK_OP_CALL_PARM);
5089 }
5090 else
5091 {
5095 }
5096 }
5097 }
5101 (gen_int_mode
5103 reg_parm_stack_space,
5106 /* Now mark the segment we just used. */
5110 NO_DEFER_POP;
5112 /* Indicate argument access so that alias.c knows that these
5113 values are live. */
5119 else
5120 {
5121 /* When arguments are pushed, trying to tell alias.c where
5122 exactly this argument is won't work, because the
5123 auto-increment causes confusion. So we merely indicate
5124 that we access something with a known mode somewhere on
5125 the stack. */
5129 }
5133 }
5134 }
5140 /* Now load any reg parms into their regs. */
5142 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
5143 are to be pushed. */
5145 {
5151 /* Handle calls that pass values in multiple non-contiguous
5152 locations. The PA64 has examples of this for library calls. */
5156 {
5158 #ifdef BLOCK_REG_PADDING
5161 /* Copied from load_register_parameters. */
5163 /* Handle case where we have a value that needs shifting
5164 up to the msb. eg. a QImode value and we're padding
5165 upward on a BYTES_BIG_ENDIAN machine. */
5169 {
5170 rtx x;
5173 /* Assigning REG here rather than a temp makes CALL_FUSAGE
5174 report the whole reg as used. Strictly speaking, the
5175 call only uses SIZE bytes at the msb end, but it doesn't
5176 seem worth generating rtl to say that. */
5181 }
5182 #endif
5183 }
5185 NO_DEFER_POP;
5186 }
5188 /* Any regs containing parms remain in use through the call. */
5190 {
5195 {
5198 {
5203 }
5204 else
5206 }
5207 }
5209 /* Pass the function the address in which to return a structure value. */
5211 {
5215 NULL_RTX)));
5218 }
5220 /* Don't allow popping to be deferred, since then
5221 cse'ing of library calls could delete a call and leave the pop. */
5222 NO_DEFER_POP;
5226 /* Stack must be properly aligned now. */
5232 /* We pass the old value of inhibit_defer_pop + 1 to emit_call_1, which
5233 will set inhibit_defer_pop to that value. */
5234 /* The return type is needed to decide how many bytes the function pops.
5235 Signedness plays no role in that, so for simplicity, we pretend it's
5236 always signed. We also assume that the list of arguments passed has
5237 no impact, so we pretend it is unknown. */
5243 struct_value_size,
5246 valreg,
5250 {
5255 }
5257 /* Right-shift returned value if necessary. */
5261 {
5264 }
5268 /* For calls to `setjmp', etc., inform function.c:setjmp_warnings
5269 that it should complain if nonvolatile values are live. For
5270 functions that cannot return, inform flow that control does not
5271 fall through. */
5273 {
5274 /* The barrier note must be emitted
5275 immediately after the CALL_INSN. Some ports emit more than
5276 just a CALL_INSN above, so we must search for it here. */
5279 {
5281 /* There was no CALL_INSN? */
5283 }
5286 }
5288 /* Consider that "regular" libcalls, i.e. all of them except for LCT_THROW
5289 and LCT_RETURNS_TWICE, cannot perform non-local gotos. */
5291 {
5294 {
5296 /* There was no CALL_INSN? */
5298 }
5301 }
5303 /* Now restore inhibit_defer_pop to its actual original value. */
5304 OK_DEFER_POP;
5308 /* Copy the value to the right place. */
5310 {
5312 {
5317 }
5319 {
5323 }
5324 else
5325 {
5326 /* Convert to the proper mode if a promotion has been active. */
5328 {
5335 }
5339 else
5341 }
5342 }
5345 {
5346 #ifdef REG_PARM_STACK_SPACE
5350 #endif
5352 /* If we saved any argument areas, restore them. */
5355 {
5364 validize_mem
5366 (gen_int_mode
5368 BLOCK_OP_CALL_PARM);
5369 else
5371 }
5376 }
5382 }
5383 \f
5385 /* Store a single argument for a function call
5386 into the register or memory area where it must be passed.
5387 *ARG describes the argument value and where to pass it.
5389 ARGBLOCK is the address of the stack-block for all the arguments,
5390 or 0 on a machine where arguments are pushed individually.
5392 MAY_BE_ALLOCA nonzero says this could be a call to `alloca'
5393 so must be careful about how the stack is used.
5395 VARIABLE_SIZE nonzero says that this was a variable-sized outgoing
5396 argument stack. This is used if ACCUMULATE_OUTGOING_ARGS to indicate
5397 that we need not worry about saving and restoring the stack.
5399 FNDECL is the declaration of the function we are calling.
5401 Return nonzero if this arg should cause sibcall failure,
5402 zero otherwise. */
5404 static int
5407 {
5418 /* Push a new temporary level for any temporaries we make for
5419 this argument. */
5423 {
5424 /* If this is being stored into a pre-allocated, fixed-size, stack area,
5425 save any previous data at that location. */
5427 {
5429 {
5430 /* stack_slot is negative, but we want to index stack_usage_map
5431 with positive values. */
5433 {
5436 }
5437 else
5441 }
5442 else
5443 {
5445 {
5448 }
5449 else
5453 }
5456 reg_parm_stack_space))
5457 {
5458 /* We need to make a save area. */
5460 machine_mode save_mode
5466 {
5467 arg->save_area
5471 stack_area,
5472 (gen_int_mode
5474 BLOCK_OP_CALL_PARM);
5475 }
5476 else
5477 {
5480 }
5481 }
5482 }
5483 }
5485 /* If this isn't going to be placed on both the stack and in registers,
5486 set up the register and number of words. */
5488 {
5491 else
5494 }
5496 /* Being passed entirely in a register. We shouldn't be called in
5497 this case. */
5500 /* If this arg needs special alignment, don't load the registers
5501 here. */
5505 /* If this is being passed partially in a register, we can't evaluate
5506 it directly into its stack slot. Otherwise, we can. */
5508 {
5509 /* stack_arg_under_construction is nonzero if a function argument is
5510 being evaluated directly into the outgoing argument list and
5511 expand_call must take special action to preserve the argument list
5512 if it is called recursively.
5514 For scalar function arguments stack_usage_map is sufficient to
5515 determine which stack slots must be saved and restored. Scalar
5516 arguments in general have pass_on_stack == 0.
5518 If this argument is initialized by a function which takes the
5519 address of the argument (a C++ constructor or a C function
5520 returning a BLKmode structure), then stack_usage_map is
5521 insufficient and expand_call must push the stack around the
5522 function call. Such arguments have pass_on_stack == 1.
5524 Note that it is always safe to set stack_arg_under_construction,
5525 but this generates suboptimal code if set when not needed. */
5528 stack_arg_under_construction++;
5531 (partial
5536 /* If we are promoting object (or for any other reason) the mode
5537 doesn't agree, convert the mode. */
5544 stack_arg_under_construction--;
5545 }
5547 /* Check for overlap with already clobbered argument area. */
5554 /* Don't allow anything left on stack from computation
5555 of argument to alloca. */
5560 /* If the value is already in the stack slot, we are done. */
5561 ;
5563 {
5566 /* Argument is a scalar, not entirely passed in registers.
5567 (If part is passed in registers, arg->partial says how much
5568 and emit_push_insn will take care of putting it there.)
5570 Push it, and if its size is less than the
5571 amount of space allocated to it,
5572 also bump stack pointer by the additional space.
5573 Note that in C the default argument promotions
5574 will prevent such mismatches. */
5579 /* Compute how much space the push instruction will push.
5580 On many machines, pushing a byte will advance the stack
5581 pointer by a halfword. */
5582 #ifdef PUSH_ROUNDING
5584 #endif
5587 /* Compute how much space the argument should get:
5588 round up to a multiple of the alignment for arguments. */
5591 /* At the moment we don't (need to) support ABIs for which the
5592 padding isn't known at compile time. In principle it should
5593 be easy to add though. */
5596 /* Compute the alignment of the pushed argument. */
5600 {
5605 }
5607 /* This isn't already where we want it on the stack, so put it there.
5608 This can either be done with push or copy insns. */
5613 reg_parm_stack_space,
5617 /* Unless this is a partially-in-register argument, the argument is now
5618 in the stack. */
5621 }
5622 else
5623 {
5624 /* BLKmode, at least partly to be pushed. */
5627 poly_int64 excess;
5628 rtx size_rtx;
5630 /* Pushing a nonscalar.
5631 If part is passed in registers, PARTIAL says how much
5632 and emit_push_insn will take care of putting it there. */
5634 /* Round its size up to a multiple
5635 of the allocation unit for arguments. */
5638 {
5641 }
5642 else
5643 {
5644 /* PUSH_ROUNDING has no effect on us, because emit_push_insn
5645 for BLKmode is careful to avoid it. */
5651 EXPAND_NORMAL);
5652 }
5656 /* When an argument is padded down, the block is aligned to
5657 PARM_BOUNDARY, but the actual argument isn't. */
5660 {
5663 else
5664 {
5665 unsigned int excess_align
5669 }
5670 }
5673 {
5674 /* emit_push_insn might not work properly if arg->value and
5675 argblock + arg->locate.offset areas overlap. */
5681 {
5682 /* arg.locate doesn't contain the pretend_args_size offset,
5683 it's part of argblock. Ensure we don't count it in I. */
5686 else
5689 /* expand_call should ensure this. */
5695 {
5696 /* Even though they appear to be at the same location,
5697 if part of the outgoing argument is in registers,
5698 they aren't really at the same location. Check for
5699 this by making sure that the incoming size is the
5700 same as the outgoing size. */
5703 }
5707 /* Use arg->locate.size.constant instead of size_rtx
5708 because we only care about the part of the argument
5709 on the stack. */
5713 }
5714 }
5720 reg_parm_stack_space,
5723 /* Unless this is a partially-in-register argument, the argument is now
5724 in the stack.
5726 ??? Unlike the case above, in which we want the actual
5727 address of the data, so that we can load it directly into a
5728 register, here we want the address of the stack slot, so that
5729 it's properly aligned for word-by-word copying or something
5730 like that. It's not clear that this is always correct. */
5733 }
5736 {
5738 arg->parallel_value
5741 }
5743 /* Mark all slots this store used. */
5748 /* Once we have pushed something, pops can't safely
5749 be deferred during the rest of the arguments. */
5750 NO_DEFER_POP;
5752 /* Free any temporary slots made in processing this argument. */
5756 }
5758 /* Nonzero if we do not know how to pass TYPE solely in registers. */
5760 bool
5762 const_tree type)
5763 {
5767 /* If the type has variable size... */
5771 /* If the type is marked as addressable (it is required
5772 to be constructed into the stack)... */
5777 }
5779 /* Another version of the TARGET_MUST_PASS_IN_STACK hook. This one
5780 takes trailing padding of a structure into account. */
5781 /* ??? Should be able to merge these two by examining BLOCK_REG_PADDING. */
5783 bool
5785 {
5789 /* If the type has variable size... */
5793 /* If the type is marked as addressable (it is required
5794 to be constructed into the stack)... */
5801 /* If the padding and mode of the type is such that a copy into
5802 a register would put it into the wrong part of the register. */
5810 }
5812 /* Tell the garbage collector about GTY markers in this source file. */