| blob | 3730f43c7a9640de804683aea6cb72383b61f7ec |
1 /* Convert function calls to rtl insns, for GNU C compiler.
2 Copyright (C) 1989-2017 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 /* A bitmap of virtual-incoming stack space. Bit is set if the corresponding
133 stack location's tail call argument has been already stored into the stack.
134 This bitmap is used to prevent sibling call optimization if function tries
135 to use parent's incoming argument slots when they have been already
136 overwritten with tail call arguments. */
139 /* stack_arg_under_construction is nonzero when an argument may be
140 initialized with a constructor call (including a C function that
141 returns a BLKmode struct) and expand_call must take special action
142 to make sure the object being constructed does not overlap the
143 argument list for the constructor call. */
148 cumulative_args_t);
175 #ifdef REG_PARM_STACK_SPACE
178 #endif
179 \f
180 /* Force FUNEXP into a form suitable for the address of a CALL,
181 and return that as an rtx. Also load the static chain register
182 if FNDECL is a nested function.
184 CALL_FUSAGE points to a variable holding the prospective
185 CALL_INSN_FUNCTION_USAGE information. */
187 rtx
190 {
191 /* Make a valid memory address and copy constants through pseudo-regs,
192 but not for a constant address if -fno-function-cse. */
194 {
195 /* If it's an indirect call by descriptor, generate code to perform
196 runtime identification of the pointer and load the descriptor. */
198 {
203 fndecl_or_type
205 fndecl_or_type);
212 /* Avoid long live ranges around function calls. */
218 /* Emit the runtime identification pattern. */
221 call_lab);
223 /* Statically predict the branch to very likely taken. */
228 /* Load the descriptor. */
237 POINTER_SIZE / BITS_PER_UNIT
246 {
249 }
251 /* Make sure we're not going to be overwritten below. */
253 }
255 /* If we are using registers for parameters, force the
256 function address into a register now. */
257 funexp = ((reg_parm_seen
261 }
262 else
263 {
264 /* funexp could be a SYMBOL_REF represents a function pointer which is
265 of ptr_mode. In this case, it should be converted into address mode
266 to be a valid address for memory rtx pattern. See PR 64971. */
271 {
274 }
275 }
280 {
281 rtx chain;
288 {
291 }
292 }
295 }
297 /* Generate instructions to call function FUNEXP,
298 and optionally pop the results.
299 The CALL_INSN is the first insn generated.
301 FNDECL is the declaration node of the function. This is given to the
302 hook TARGET_RETURN_POPS_ARGS to determine whether this function pops
303 its own args.
305 FUNTYPE is the data type of the function. This is given to the hook
306 TARGET_RETURN_POPS_ARGS to determine whether this function pops its
307 own args. We used to allow an identifier for library functions, but
308 that doesn't work when the return type is an aggregate type and the
309 calling convention says that the pointer to this aggregate is to be
310 popped by the callee.
312 STACK_SIZE is the number of bytes of arguments on the stack,
313 ROUNDED_STACK_SIZE is that number rounded up to
314 PREFERRED_STACK_BOUNDARY; zero if the size is variable. This is
315 both to put into the call insn and to generate explicit popping
316 code if necessary.
318 STRUCT_VALUE_SIZE is the number of bytes wanted in a structure value.
319 It is zero if this call doesn't want a structure value.
321 NEXT_ARG_REG is the rtx that results from executing
322 targetm.calls.function_arg (&args_so_far, VOIDmode, void_type_node, true)
323 just after all the args have had their registers assigned.
324 This could be whatever you like, but normally it is the first
325 arg-register beyond those used for args in this call,
326 or 0 if all the arg-registers are used in this call.
327 It is passed on to `gen_call' so you can put this info in the call insn.
329 VALREG is a hard register in which a value is returned,
330 or 0 if the call does not return a value.
332 OLD_INHIBIT_DEFER_POP is the value that `inhibit_defer_pop' had before
333 the args to this call were processed.
334 We restore `inhibit_defer_pop' to that value.
336 CALL_FUSAGE is either empty or an EXPR_LIST of USE expressions that
337 denote registers used by the called function. */
339 static void
341 tree funtype ATTRIBUTE_UNUSED,
342 HOST_WIDE_INT stack_size ATTRIBUTE_UNUSED,
343 HOST_WIDE_INT rounded_stack_size,
344 HOST_WIDE_INT struct_value_size ATTRIBUTE_UNUSED,
347 cumulative_args_t args_so_far ATTRIBUTE_UNUSED)
348 {
354 /* Sibling call patterns never pop arguments (no sibcall(_value)_pop
355 patterns exist). Any popping that the callee does on return will
356 be from our caller's frame rather than ours. */
358 {
361 #ifdef CALL_POPS_ARGS
363 #endif
364 }
366 /* Ensure address is valid. SYMBOL_REF is already valid, so no need,
367 and we don't want to load it into a register as an optimization,
368 because prepare_call_address already did it if it should be done. */
374 {
377 /* Although a built-in FUNCTION_DECL and its non-__builtin
378 counterpart compare equal and get a shared mem_attrs, they
379 produce different dump output in compare-debug compilations,
380 if an entry gets garbage collected in one compilation, then
381 adds a different (but equivalent) entry, while the other
382 doesn't run the garbage collector at the same spot and then
383 shares the mem_attr with the equivalent entry. */
385 {
389 }
392 }
397 {
400 rounded_stack_size_rtx,
402 else
405 }
406 /* If the target has "call" or "call_value" insns, then prefer them
407 if no arguments are actually popped. If the target does not have
408 "call" or "call_value" insns, then we must use the popping versions
409 even if the call has no arguments to pop. */
411 || !(valreg
414 {
417 /* If this subroutine pops its own args, record that in the call insn
418 if possible, for the sake of frame pointer elimination. */
422 rounded_stack_size_rtx,
424 else
429 }
430 else
431 {
435 else
438 }
441 /* Find the call we just emitted. */
444 /* Some target create a fresh MEM instead of reusing the one provided
445 above. Set its MEM_EXPR. */
452 /* Mark instrumented calls. */
456 /* Put the register usage information there. */
459 /* If this is a const call, then set the insn's unchanging bit. */
463 /* If this is a pure call, then set the insn's unchanging bit. */
467 /* If this is a const call, then set the insn's unchanging bit. */
471 /* Create a nothrow REG_EH_REGION note, if needed. */
478 {
481 }
485 /* Restore this now, so that we do defer pops for this call's args
486 if the context of the call as a whole permits. */
490 {
502 /* If popup is needed, stack realign must use DRAP */
505 }
506 /* For noreturn calls when not accumulating outgoing args force
507 REG_ARGS_SIZE note to prevent crossjumping of calls with different
508 args sizes. */
513 {
514 /* If returning from the subroutine does not automatically pop the args,
515 we need an instruction to pop them sooner or later.
516 Perhaps do it now; perhaps just record how much space to pop later.
518 If returning from the subroutine does pop the args, indicate that the
519 stack pointer will be changed. */
522 {
524 /* Just pretend we did the pop. */
529 else
531 }
532 }
533 /* When we accumulate outgoing args, we must avoid any stack manipulations.
534 Restore the stack pointer to its original value now. Usually
535 ACCUMULATE_OUTGOING_ARGS targets don't get here, but there are exceptions.
536 On i386 ACCUMULATE_OUTGOING_ARGS can be enabled on demand, and
537 popping variants of functions exist as well.
539 ??? We may optimize similar to defer_pop above, but it is
540 probably not worthwhile.
542 ??? It will be worthwhile to enable combine_stack_adjustments even for
543 such machines. */
546 }
548 /* Determine if the function identified by FNDECL is one with
549 special properties we wish to know about. Modify FLAGS accordingly.
551 For example, if the function might return more than one time (setjmp), then
552 set ECF_RETURNS_TWICE.
554 Set ECF_MAY_BE_ALLOCA for any memory allocation function that might allocate
555 space from the stack such as alloca. */
557 static int
559 {
562 /* For instrumentation clones we want to derive flags
563 from the original name. */
570 /* Exclude functions not at the file scope, or not `extern',
571 since they are not the magic functions we would otherwise
572 think they are.
573 FIXME: this should be handled with attributes, not with this
574 hacky imitation of DECL_ASSEMBLER_NAME. It's (also) wrong
575 because you can declare fork() inside a function if you
576 wish. */
580 {
584 /* We assume that alloca will always be called by name. It
585 makes no sense to pass it as a pointer-to-function to
586 anything that does not understand its behavior. */
592 /* Disregard prefix _ or __. */
594 {
597 else
599 }
601 /* ECF_RETURNS_TWICE is safe even for -ffreestanding. */
608 }
615 }
617 /* Similar to special_function_p; return a set of ERF_ flags for the
618 function FNDECL. */
619 static int
621 {
622 tree attr;
636 {
649 }
650 }
652 /* Return nonzero when FNDECL represents a call to setjmp. */
654 int
656 {
660 }
663 /* Return true if STMT may be an alloca call. */
665 bool
667 {
668 tree fndecl;
678 }
680 /* Return true if STMT is a builtin alloca call. */
682 bool
684 {
685 tree fndecl;
693 {
694 CASE_BUILT_IN_ALLOCA:
698 }
701 }
703 /* Return true when exp contains a builtin alloca call. */
705 bool
707 {
708 tree fndecl;
713 {
714 CASE_BUILT_IN_ALLOCA:
718 }
721 }
723 /* Return TRUE if FNDECL is either a TM builtin or a TM cloned
724 function. Return FALSE otherwise. */
726 static bool
728 {
736 {
738 {
781 }
782 }
784 }
786 /* Detect flags (function attributes) from the function decl or type node. */
788 int
790 {
794 {
795 /* The function exp may have the `malloc' attribute. */
799 /* The function exp may have the `returns_twice' attribute. */
803 /* Process the pure and const attributes. */
822 {
829 }
832 }
834 {
842 }
843 else
847 {
851 }
854 }
856 /* Detect flags from a CALL_EXPR. */
858 int
860 {
868 else
869 {
873 else
877 }
880 }
882 /* Return true if TYPE should be passed by invisible reference. */
884 bool
887 {
889 {
890 /* If this type contains non-trivial constructors, then it is
891 forbidden for the middle-end to create any new copies. */
895 /* GCC post 3.4 passes *all* variable sized types by reference. */
899 /* If a record type should be passed the same as its first (and only)
900 member, use the type and mode of that member. */
902 {
905 }
906 }
910 }
912 /* Return true if TYPE, which is passed by reference, should be callee
913 copied instead of caller copied. */
915 bool
918 {
922 named_arg);
923 }
926 /* Precompute all register parameters as described by ARGS, storing values
927 into fields within the ARGS array.
929 NUM_ACTUALS indicates the total number elements in the ARGS array.
931 Set REG_PARM_SEEN if we encounter a register parameter. */
933 static void
936 {
943 {
947 {
952 }
954 /* If we are to promote the function arg to a wider mode,
955 do it now. */
963 /* If the value is a non-legitimate constant, force it into a
964 pseudo now. TLS symbols sometimes need a call to resolve. */
969 /* If we're going to have to load the value by parts, pull the
970 parts into pseudos. The part extraction process can involve
971 non-trivial computation. */
973 {
978 }
980 /* If the value is expensive, and we are inside an appropriately
981 short loop, put the value into a pseudo and then put the pseudo
982 into the hard reg.
984 For small register classes, also do this if this call uses
985 register parameters. This is to avoid reload conflicts while
986 loading the parameters registers. */
995 && ((*reg_parm_seen
999 }
1000 }
1002 #ifdef REG_PARM_STACK_SPACE
1004 /* The argument list is the property of the called routine and it
1005 may clobber it. If the fixed area has been used for previous
1006 parameters, we must save and restore it. */
1008 static rtx
1009 save_fixed_argument_area (int reg_parm_stack_space, rtx argblock, int *low_to_save, int *high_to_save)
1010 {
1014 /* Compute the boundary of the area that needs to be saved, if any. */
1024 {
1026 machine_mode save_mode;
1028 rtx addr;
1029 rtx stack_area;
1030 rtx save_area;
1033 ;
1040 /* If we don't have the required alignment, must do this
1041 in BLKmode. */
1042 scalar_int_mode imode;
1047 else
1052 else
1060 {
1064 }
1065 else
1066 {
1069 }
1072 }
1075 }
1077 static void
1079 {
1086 else
1095 else
1098 BLOCK_OP_CALL_PARM);
1099 }
1102 /* If any elements in ARGS refer to parameters that are to be passed in
1103 registers, but not in memory, and whose alignment does not permit a
1104 direct copy into registers. Copy the values into a group of pseudos
1105 which we will later copy into the appropriate hard registers.
1107 Pseudos for each unaligned argument will be stored into the array
1108 args[argnum].aligned_regs. The caller is responsible for deallocating
1109 the aligned_regs array if it is nonzero. */
1111 static void
1113 {
1123 {
1128 {
1131 }
1132 else
1133 {
1136 }
1140 /* Structures smaller than a word are normally aligned to the
1141 least significant byte. On a BYTES_BIG_ENDIAN machine,
1142 this means we must skip the empty high order bytes when
1143 calculating the bit offset. */
1145 #ifdef BLOCK_REG_PADDING
1149 #else
1150 && BYTES_BIG_ENDIAN
1151 #endif
1152 )
1156 {
1165 /* There is no need to restrict this code to loading items
1166 in TYPE_ALIGN sized hunks. The bitfield instructions can
1167 load up entire word sized registers efficiently.
1169 ??? This may not be needed anymore.
1170 We use to emit a clobber here but that doesn't let later
1171 passes optimize the instructions we emit. By storing 0 into
1172 the register later passes know the first AND to zero out the
1173 bitfield being set in the register is unnecessary. The store
1174 of 0 will be deleted as will at least the first AND. */
1181 }
1182 }
1183 }
1185 /* The limit set by -Walloc-larger-than=. */
1188 /* Initialize ALLOC_OBJECT_SIZE_LIMIT based on the -Walloc-size-larger-than=
1189 setting if the option is specified, or to the maximum object size if it
1190 is not. Return the initialized value. */
1192 static tree
1194 {
1196 {
1200 {
1204 unsigned HOST_WIDE_INT limit
1208 {
1210 {
1211 /* Numeric option arguments are at most INT_MAX. Make it
1212 possible to specify a larger value by accepting common
1213 suffixes. */
1240 else
1242 }
1245 {
1249 }
1250 }
1251 }
1252 }
1254 }
1256 /* Return true when EXP's range can be determined and set RANGE[] to it
1257 after adjusting it if necessary to make EXP a valid size argument to
1258 an allocation function declared with attribute alloc_size (whose
1259 argument may be signed), or to a string manipulation function like
1260 memset. */
1262 bool
1264 {
1266 {
1267 /* EXP is a constant. */
1270 }
1273 enum value_range_type range_type
1278 {
1279 /* No range information available. */
1283 }
1291 {
1293 {
1295 {
1296 /* EXP is not in a strictly negative range. That means
1297 it must be in some (not necessarily strictly) positive
1298 range which includes zero. Since in signed to unsigned
1299 conversions negative values end up converted to large
1300 positive values, and otherwise they are not valid sizes,
1301 the resulting range is in both cases [0, TYPE_MAX]. */
1304 }
1306 {
1307 /* EXP is not in a negative-positive range. That means EXP
1308 is either negative, or greater than max. Since negative
1309 sizes are invalid make the range [MAX + 1, TYPE_MAX]. */
1312 }
1313 else
1314 {
1317 }
1318 }
1320 {
1321 /* EXP is unsigned and not in the range [1, MAX]. That means
1322 it's either zero or greater than MAX. Even though 0 would
1323 normally be detected by -Walloc-zero set the range to
1324 [MAX, TYPE_MAX] so that when MAX is greater than the limit
1325 the whole range is diagnosed. */
1328 }
1329 else
1330 {
1333 }
1334 }
1340 }
1342 /* Diagnose a call EXP to function FN decorated with attribute alloc_size
1343 whose argument numbers given by IDX with values given by ARGS exceed
1344 the maximum object size or cause an unsigned oveflow (wrapping) when
1345 multiplied. When ARGS[0] is null the function does nothing. ARGS[1]
1346 may be null for functions like malloc, and non-null for those like
1347 calloc that are decorated with a two-argument attribute alloc_size. */
1349 void
1351 {
1352 /* The range each of the (up to) two arguments is known to be in. */
1355 /* Maximum object size set by -Walloc-size-larger-than= or SIZE_MAX / 2. */
1362 /* Validate each argument individually. */
1364 {
1366 {
1371 {
1375 }
1377 {
1378 /* Avoid issuing -Walloc-zero for allocation functions other
1379 than __builtin_alloca that are declared with attribute
1380 returns_nonnull because there's no portability risk. This
1381 avoids warning for such calls to libiberty's xmalloc and
1382 friends.
1383 Also avoid issuing the warning for calls to function named
1384 "alloca". */
1393 }
1395 {
1396 /* G++ emits calls to ::operator new[](SIZE_MAX) in C++98
1397 mode and with -fno-exceptions as a way to indicate array
1398 size overflow. There's no good way to detect C++98 here
1399 so avoid diagnosing these calls for all C++ modes. */
1408 "%Kargument %i value %qE exceeds "
1411 }
1412 }
1415 {
1416 /* Verify that the argument's range is not negative (including
1417 upper bound of zero). */
1420 {
1425 }
1427 {
1429 "%Kargument %i range [%E, %E] exceeds "
1433 maxobjsize);
1434 }
1435 }
1436 }
1441 /* For a two-argument alloc_size, validate the product of the two
1442 arguments if both of their values or ranges are known. */
1447 {
1448 /* Check for overflow in the product of a function decorated with
1449 attribute alloc_size (X, Y). */
1459 "%Kproduct %<%E * %E%> of arguments %i and %i "
1465 "%Kproduct %<%E * %E%> of arguments %i and %i "
1469 maxobjsize);
1472 {
1473 /* Print the full range of each of the two arguments to make
1474 it clear when it is, in fact, in a range and not constant. */
1481 }
1482 }
1485 {
1491 else
1494 }
1495 }
1497 /* Issue an error if CALL_EXPR was flagged as requiring
1498 tall-call optimization. */
1500 static void
1502 {
1508 }
1510 /* Fill in ARGS_SIZE and ARGS array based on the parameters found in
1511 CALL_EXPR EXP.
1513 NUM_ACTUALS is the total number of parameters.
1515 N_NAMED_ARGS is the total number of named arguments.
1517 STRUCT_VALUE_ADDR_VALUE is the implicit argument for a struct return
1518 value, or null.
1520 FNDECL is the tree code for the target of this call (if known)
1522 ARGS_SO_FAR holds state needed by the target to know where to place
1523 the next argument.
1525 REG_PARM_STACK_SPACE is the number of bytes of stack space reserved
1526 for arguments which are passed in registers.
1528 OLD_STACK_LEVEL is a pointer to an rtx which olds the old stack level
1529 and may be modified by this routine.
1531 OLD_PENDING_ADJ, MUST_PREALLOCATE and FLAGS are pointers to integer
1532 flags which may be modified by this routine.
1534 MAY_TAILCALL is cleared if we encounter an invisible pass-by-reference
1535 that requires allocation of stack space.
1537 CALL_FROM_THUNK_P is true if this call is the jump from a thunk to
1538 the thunked-to function. */
1540 static void
1547 cumulative_args_t args_so_far,
1552 {
1556 /* Count arg position in order args appear. */
1566 /* In this loop, we consider args in the order they are written.
1567 We fill up ARGS from the back. */
1570 {
1572 call_expr_arg_iterator iter;
1573 tree arg;
1577 {
1579 j--;
1581 /* If we pass structure address then we need to
1582 create bounds for it. Since created bounds is
1583 a call statement, we expand it right here to avoid
1584 fixing all other places where it may be expanded. */
1586 {
1593 j--;
1594 }
1595 }
1598 {
1601 /* Remember last param with pointer and associate it
1602 with following pointer bounds. */
1605 {
1610 {
1613 }
1614 }
1618 {
1622 }
1624 {
1625 /* We expect bounds in instrumented calls only.
1626 Otherwise it is a sign we lost flag due to some optimization
1627 and may emit call args incorrectly. */
1630 /* For structures look for the next available pointer. */
1632 {
1639 /* Check we have no more pointers in the structure. */
1642 }
1645 /* Check we covered all pointers in the previous
1646 non bounds arg. */
1649 }
1650 else
1654 && argtype
1657 {
1660 j--;
1662 }
1663 else
1665 j--;
1666 argpos++;
1667 }
1671 }
1675 /* Extract attribute alloc_size and if set, store the indices of
1676 the corresponding arguments in ALLOC_IDX, and then the actual
1677 argument(s) at those indices in ALLOC_ARGS. */
1683 {
1688 }
1690 /* Array for up to the two attribute alloc_size arguments. */
1693 /* I counts args in order (to be) pushed; ARGPOS counts in order written. */
1695 {
1698 machine_mode mode;
1700 /* Replace erroneous argument with constant zero. */
1704 /* If TYPE is a transparent union or record, pass things the way
1705 we would pass the first field of the union or record. We have
1706 already verified that the modes are the same. */
1711 /* Decide where to pass this arg.
1713 args[i].reg is nonzero if all or part is passed in registers.
1715 args[i].partial is nonzero if part but not all is passed in registers,
1716 and the exact value says how many bytes are passed in registers.
1718 args[i].pass_on_stack is nonzero if the argument must at least be
1719 computed on the stack. It may then be loaded back into registers
1720 if args[i].reg is nonzero.
1722 These decisions are driven by the FUNCTION_... macros and must agree
1723 with those made by function.c. */
1725 /* See if this argument should be passed by invisible reference. */
1728 {
1732 callee_copies
1736 /* If we're compiling a thunk, pass through invisible references
1737 instead of making a copy. */
1739 || (callee_copies
1744 {
1745 /* We may have turned the parameter value into an SSA name.
1746 Go back to the original parameter so we can take the
1747 address. */
1749 {
1753 }
1754 /* Argument setup code may have copied the value to register. We
1755 revert that optimization now because the tail call code must
1756 use the original location. */
1766 /* We can't use sibcalls if a callee-copied argument is
1767 stored in the current function's frame. */
1769 {
1772 "a callee-copied argument is"
1773 " stored in the current "
1775 }
1783 }
1784 else
1785 {
1786 /* We make a copy of the object and pass the address to the
1787 function being called. */
1788 rtx copy;
1795 {
1796 /* This is a variable-sized object. Make space on the stack
1797 for it. */
1801 {
1805 }
1807 /* We can pass TRUE as the 4th argument because we just
1808 saved the stack pointer and will restore it right after
1809 the call. */
1813 max_int_size_in_bytes
1818 }
1819 else
1824 /* Just change the const function to pure and then let
1825 the next test clear the pure based on
1826 callee_copies. */
1828 {
1831 }
1841 "argument must be passed"
1843 }
1844 }
1857 {
1860 }
1862 /* If this is a sibling call and the machine has register windows, the
1863 register window has to be unwinded before calling the routine, so
1864 arguments have to go into the incoming registers. */
1869 else
1879 /* If FUNCTION_ARG returned a (parallel [(expr_list (nil) ...) ...]),
1880 it means that we are to pass this arg in the register(s) designated
1881 by the PARALLEL, but also to pass it in the stack. */
1886 /* If this is an addressable type, we must preallocate the stack
1887 since we must evaluate the object into its final location.
1889 If this is to be passed in both registers and the stack, it is simpler
1890 to preallocate. */
1895 /* No stack allocation and padding for bounds. */
1897 ;
1898 /* Compute the stack-size of this argument. */
1903 #ifdef STACK_PARMS_IN_REG_PARM_AREA
1905 #else
1907 #endif
1908 reg_parm_stack_space,
1911 #ifdef BLOCK_REG_PADDING
1912 else
1913 /* The argument is passed entirely in registers. See at which
1914 end it should be padded. */
1918 #endif
1920 /* Update ARGS_SIZE, the total stack space for args so far. */
1926 /* Increment ARGS_SO_FAR, which has info about which arg-registers
1927 have been used, etc. */
1932 /* Store argument values for functions decorated with attribute
1933 alloc_size. */
1938 }
1941 {
1942 /* Check the arguments of functions decorated with attribute
1943 alloc_size. */
1945 }
1946 }
1948 /* Update ARGS_SIZE to contain the total size for the argument block.
1949 Return the original constant component of the argument block's size.
1951 REG_PARM_STACK_SPACE holds the number of bytes of stack space reserved
1952 for arguments passed in registers. */
1954 static int
1957 tree fndecl ATTRIBUTE_UNUSED,
1958 tree fntype ATTRIBUTE_UNUSED,
1960 {
1963 /* For accumulate outgoing args mode we don't need to align, since the frame
1964 will be already aligned. Align to STACK_BOUNDARY in order to prevent
1965 backends from generating misaligned frame sizes. */
1969 /* Compute the actual size of the argument block required. The variable
1970 and constant sizes must be combined, the size may have to be rounded,
1971 and there may be a minimum required size. */
1974 {
1980 {
1981 /* We don't handle this case yet. To handle it correctly we have
1982 to add the delta, round and subtract the delta.
1983 Currently no machine description requires this support. */
1986 }
1989 {
1990 args_size->var
1994 /* The area corresponding to register parameters is not to count in
1995 the size of the block we need. So make the adjustment. */
1997 args_size->var
2000 }
2001 }
2002 else
2003 {
2008 + stack_pointer_delta
2010 / preferred_stack_boundary
2015 reg_parm_stack_space);
2019 }
2021 }
2023 /* Precompute parameters as needed for a function call.
2025 FLAGS is mask of ECF_* constants.
2027 NUM_ACTUALS is the number of arguments.
2029 ARGS is an array containing information for each argument; this
2030 routine fills in the INITIAL_VALUE and VALUE fields for each
2031 precomputed argument. */
2033 static void
2035 {
2038 /* If this is a libcall, then precompute all arguments so that we do not
2039 get extraneous instructions emitted as part of the libcall sequence. */
2041 /* If we preallocated the stack space, and some arguments must be passed
2042 on the stack, then we must precompute any parameter which contains a
2043 function call which will store arguments on the stack.
2044 Otherwise, evaluating the parameter may clobber previous parameters
2045 which have already been stored into the stack. (we have code to avoid
2046 such case by saving the outgoing stack arguments, but it results in
2047 worse code) */
2052 {
2053 tree type;
2054 machine_mode mode;
2059 /* If this is an addressable type, we cannot pre-evaluate it. */
2068 {
2074 /* CSE will replace this only if it contains args[i].value
2075 pseudo, so convert it down to the declared mode using
2076 a SUBREG. */
2080 {
2085 }
2086 }
2087 }
2088 }
2090 /* Given the current state of MUST_PREALLOCATE and information about
2091 arguments to a function call in NUM_ACTUALS, ARGS and ARGS_SIZE,
2092 compute and return the final value for MUST_PREALLOCATE. */
2094 static int
2097 {
2098 /* See if we have or want to preallocate stack space.
2100 If we would have to push a partially-in-regs parm
2101 before other stack parms, preallocate stack space instead.
2103 If the size of some parm is not a multiple of the required stack
2104 alignment, we must preallocate.
2106 If the total size of arguments that would otherwise create a copy in
2107 a temporary (such as a CALL) is more than half the total argument list
2108 size, preallocation is faster.
2110 Another reason to preallocate is if we have a machine (like the m88k)
2111 where stack alignment is required to be maintained between every
2112 pair of insns, not just when the call is made. However, we assume here
2113 that such machines either do not have push insns (and hence preallocation
2114 would occur anyway) or the problem is taken care of with
2115 PUSH_ROUNDING. */
2118 {
2124 {
2129 /* We preallocate in case there are bounds passed
2130 in the bounds table to have precomputed address
2131 for bounds association. */
2141 copy_to_evaluate_size
2143 }
2148 }
2150 }
2152 /* If we preallocated stack space, compute the address of each argument
2153 and store it into the ARGS array.
2155 We need not ensure it is a valid memory address here; it will be
2156 validized when it is used.
2158 ARGBLOCK is an rtx for the address of the outgoing arguments. */
2160 static void
2162 {
2164 {
2172 {
2175 rtx addr;
2180 /* Skip this parm if it will not be passed on the stack. */
2186 /* Pointer Bounds are never passed on the stack. */
2194 {
2195 /* Only part of the parameter is being passed on the stack.
2196 Generate a simple memory reference of the correct size. */
2202 }
2203 else
2204 {
2208 }
2214 {
2217 }
2224 {
2225 /* Only part of the parameter is being passed on the stack.
2226 Generate a simple memory reference of the correct size.
2227 */
2230 }
2231 else
2232 {
2236 }
2239 /* Function incoming arguments may overlap with sibling call
2240 outgoing arguments and we cannot allow reordering of reads
2241 from function arguments with stores to outgoing arguments
2242 of sibling calls. */
2245 }
2246 }
2247 }
2249 /* Given a FNDECL and EXP, return an rtx suitable for use as a target address
2250 in a call instruction.
2252 FNDECL is the tree node for the target function. For an indirect call
2253 FNDECL will be NULL_TREE.
2255 ADDR is the operand 0 of CALL_EXPR for this call. */
2257 static rtx
2259 {
2260 rtx funexp;
2262 /* Get the function to call, in the form of RTL. */
2264 {
2268 /* Get a SYMBOL_REF rtx for the function address. */
2270 }
2271 else
2272 /* Generate an rtx (probably a pseudo-register) for the address. */
2273 {
2277 }
2279 }
2281 /* Internal state for internal_arg_pointer_based_exp and its helpers. */
2282 static struct
2283 {
2284 /* Last insn that has been scanned by internal_arg_pointer_based_exp_scan,
2285 or NULL_RTX if none has been scanned yet. */
2287 /* Vector indexed by REGNO - FIRST_PSEUDO_REGISTER, recording if a pseudo is
2288 based on crtl->args.internal_arg_pointer. The element is NULL_RTX if the
2289 pseudo isn't based on it, a CONST_INT offset if the pseudo is based on it
2290 with fixed offset, or PC if this is with variable or unknown offset. */
2296 /* Helper function for internal_arg_pointer_based_exp. Scan insns in
2297 the tail call sequence, starting with first insn that hasn't been
2298 scanned yet, and note for each pseudo on the LHS whether it is based
2299 on crtl->args.internal_arg_pointer or not, and what offset from that
2300 that pointer it has. */
2302 static void
2304 {
2309 else
2313 {
2316 {
2319 /* Punt on pseudos set multiple times. */
2324 else
2327 {
2329 internal_arg_pointer_exp_state.cache
2332 }
2333 }
2337 }
2340 }
2342 /* Compute whether RTL is based on crtl->args.internal_arg_pointer. Return
2343 NULL_RTX if RTL isn't based on it, a CONST_INT offset if RTL is based on
2344 it with fixed offset, or PC if this is with variable or unknown offset.
2345 TOPLEVEL is true if the function is invoked at the topmost level. */
2347 static rtx
2349 {
2360 {
2365 }
2367 /* When called at the topmost level, scan pseudo assignments in between the
2368 last scanned instruction in the tail call sequence and the latest insn
2369 in that sequence. */
2374 {
2380 }
2384 {
2390 }
2393 }
2395 /* Return true if and only if SIZE storage units (usually bytes)
2396 starting from address ADDR overlap with already clobbered argument
2397 area. This function is used to determine if we should give up a
2398 sibcall. */
2400 static bool
2402 {
2403 HOST_WIDE_INT i;
2404 rtx val;
2413 else
2418 else
2426 {
2433 }
2436 }
2438 /* Do the register loads required for any wholly-register parms or any
2439 parms which are passed both on the stack and in a register. Their
2440 expressions were already evaluated.
2442 Mark all register-parms as living through the call, putting these USE
2443 insns in the CALL_INSN_FUNCTION_USAGE field.
2445 When IS_SIBCALL, perform the check_sibcall_argument_overlap
2446 checking, setting *SIBCALL_FAILURE if appropriate. */
2448 static void
2452 {
2456 {
2460 {
2465 /* Set non-negative if we must move a word at a time, even if
2466 just one word (e.g, partial == 4 && mode == DFmode). Set
2467 to -1 if we just use a normal move insn. This value can be
2468 zero if the argument is a zero size structure. */
2471 ;
2473 {
2476 }
2478 {
2481 }
2482 else
2485 /* Handle calls that pass values in multiple non-contiguous
2486 locations. The Irix 6 ABI has examples of this. */
2491 /* If simple case, just do move. If normal partial, store_one_arg
2492 has already loaded the register for us. In all other cases,
2493 load the register(s) from memory. */
2496 {
2498 #ifdef BLOCK_REG_PADDING
2499 /* Handle case where we have a value that needs shifting
2500 up to the msb. eg. a QImode value and we're padding
2501 upward on a BYTES_BIG_ENDIAN machine. */
2505 {
2506 rtx x;
2509 /* Assigning REG here rather than a temp makes CALL_FUSAGE
2510 report the whole reg as used. Strictly speaking, the
2511 call only uses SIZE bytes at the msb end, but it doesn't
2512 seem worth generating rtl to say that. */
2517 }
2518 #endif
2519 }
2521 /* If we have pre-computed the values to put in the registers in
2522 the case of non-aligned structures, copy them in now. */
2530 {
2533 /* Check for overlap with already clobbered argument area,
2534 providing that this has non-zero size. */
2537 && (mem_overlaps_already_clobbered_arg_p
2544 else
2545 {
2554 NULL);
2560 }
2562 /* Handle a BLKmode that needs shifting. */
2564 #ifdef BLOCK_REG_PADDING
2566 #else
2567 && BYTES_BIG_ENDIAN
2568 #endif
2569 )
2570 {
2575 rtx x;
2580 }
2581 }
2583 /* When a parameter is a block, and perhaps in other cases, it is
2584 possible that it did a load from an argument slot that was
2585 already clobbered. */
2590 /* Handle calls that pass values in multiple non-contiguous
2591 locations. The Irix 6 ABI has examples of this. */
2599 }
2600 }
2601 }
2603 /* We need to pop PENDING_STACK_ADJUST bytes. But, if the arguments
2604 wouldn't fill up an even multiple of PREFERRED_UNIT_STACK_BOUNDARY
2605 bytes, then we would need to push some additional bytes to pad the
2606 arguments. So, we compute an adjust to the stack pointer for an
2607 amount that will leave the stack under-aligned by UNADJUSTED_ARGS_SIZE
2608 bytes. Then, when the arguments are pushed the stack will be perfectly
2609 aligned. ARGS_SIZE->CONSTANT is set to the number of bytes that should
2610 be popped after the call. Returns the adjustment. */
2612 static int
2616 {
2617 /* The number of bytes to pop so that the stack will be
2618 under-aligned by UNADJUSTED_ARGS_SIZE bytes. */
2619 HOST_WIDE_INT adjustment;
2620 /* The alignment of the stack after the arguments are pushed, if we
2621 just pushed the arguments without adjust the stack here. */
2624 unadjusted_alignment
2628 /* We want to get rid of as many of the PENDING_STACK_ADJUST bytes
2629 as possible -- leaving just enough left to cancel out the
2630 UNADJUSTED_ALIGNMENT. In other words, we want to ensure that the
2631 PENDING_STACK_ADJUST is non-negative, and congruent to
2632 -UNADJUSTED_ALIGNMENT modulo the PREFERRED_UNIT_STACK_BOUNDARY. */
2634 /* Begin by trying to pop all the bytes. */
2635 unadjusted_alignment
2636 = (unadjusted_alignment
2639 /* Push enough additional bytes that the stack will be aligned
2640 after the arguments are pushed. */
2644 /* Now, sets ARGS_SIZE->CONSTANT so that we pop the right number of
2645 bytes after the call. The right number is the entire
2646 PENDING_STACK_ADJUST less our ADJUSTMENT plus the amount required
2647 by the arguments in the first place. */
2648 args_size->constant
2652 }
2654 /* Scan X expression if it does not dereference any argument slots
2655 we already clobbered by tail call arguments (as noted in stored_args_map
2656 bitmap).
2657 Return nonzero if X expression dereferences such argument slots,
2658 zero otherwise. */
2660 static int
2662 {
2663 RTX_CODE code;
2672 /* We need not check the operands of the CALL expression itself. */
2680 /* Scan all subexpressions. */
2683 {
2685 {
2688 }
2690 {
2694 }
2695 }
2697 }
2699 /* Scan sequence after INSN if it does not dereference any argument slots
2700 we already clobbered by tail call arguments (as noted in stored_args_map
2701 bitmap). If MARK_STORED_ARGS_MAP, add stack slots for ARG to
2702 stored_args_map bitmap afterwards (when ARG is a register MARK_STORED_ARGS_MAP
2703 should be 0). Return nonzero if sequence after INSN dereferences such argument
2704 slots, zero otherwise. */
2706 static int
2709 {
2714 else
2723 {
2726 else
2731 }
2733 }
2735 /* Given that a function returns a value of mode MODE at the most
2736 significant end of hard register VALUE, shift VALUE left or right
2737 as specified by LEFT_P. Return true if some action was needed. */
2739 bool
2741 {
2742 HOST_WIDE_INT shift;
2749 /* Use ashr rather than lshr for right shifts. This is for the benefit
2750 of the MIPS port, which requires SImode values to be sign-extended
2751 when stored in 64-bit registers. */
2756 }
2758 /* If X is a likely-spilled register value, copy it to a pseudo
2759 register and return that register. Return X otherwise. */
2761 static rtx
2763 {
2764 rtx new_rtx;
2769 {
2770 /* Make sure that we generate a REG rather than a CONCAT.
2771 Moves into CONCATs can need nontrivial instructions,
2772 and the whole point of this function is to avoid
2773 using the hard register directly in such a situation. */
2779 }
2781 }
2783 /* Helper function for expand_call.
2784 Return false is EXP is not implementable as a sibling call. */
2786 static bool
2788 rtx structure_value_addr,
2789 tree funtype,
2791 tree fndecl,
2793 tree addr,
2795 {
2797 {
2798 maybe_complain_about_tail_call
2800 "machine description does not have"
2803 }
2805 /* Doing sibling call optimization needs some work, since
2806 structure_value_addr can be allocated on the stack.
2807 It does not seem worth the effort since few optimizable
2808 sibling calls will return a structure. */
2810 {
2813 }
2815 #ifdef REG_PARM_STACK_SPACE
2816 /* If outgoing reg parm stack space changes, we can not do sibcall. */
2820 {
2822 "inconsistent size of stack space"
2823 " allocated for arguments which are"
2826 }
2827 #endif
2829 /* Check whether the target is able to optimize the call
2830 into a sibcall. */
2832 {
2834 "target is not able to optimize the"
2837 }
2839 /* Functions that do not return exactly once may not be sibcall
2840 optimized. */
2842 {
2845 }
2847 {
2850 }
2853 {
2856 }
2858 /* If the called function is nested in the current one, it might access
2859 some of the caller's arguments, but could clobber them beforehand if
2860 the argument areas are shared. */
2862 {
2865 }
2867 /* If this function requires more stack slots than the current
2868 function, we cannot change it into a sibling call.
2869 crtl->args.pretend_args_size is not part of the
2870 stack allocated by our caller. */
2872 {
2874 "callee required more stack slots"
2877 }
2879 /* If the callee pops its own arguments, then it must pop exactly
2880 the same number of arguments as the current function. */
2885 {
2887 "inconsistent number of"
2890 }
2893 {
2897 }
2899 /* All checks passed. */
2901 }
2903 /* Generate all the code for a CALL_EXPR exp
2904 and return an rtx for its value.
2905 Store the value in TARGET (specified as an rtx) if convenient.
2906 If the value is stored in TARGET then TARGET is returned.
2907 If IGNORE is nonzero, then we ignore the value of the function call. */
2909 rtx
2911 {
2912 /* Nonzero if we are currently expanding a call. */
2915 /* RTX for the function to be called. */
2916 rtx funexp;
2917 /* Sequence of insns to perform a normal "call". */
2919 /* Sequence of insns to perform a tail "call". */
2921 /* Data type of the function. */
2922 tree funtype;
2923 tree type_arg_types;
2924 tree rettype;
2925 /* Declaration of the function being called,
2926 or 0 if the function is computed (not known by name). */
2928 /* The type of the function being called. */
2929 tree fntype;
2934 /* Register in which non-BLKmode value will be returned,
2935 or 0 if no value or if value is BLKmode. */
2936 rtx valreg;
2937 /* Register(s) in which bounds are returned. */
2939 /* Address where we should return a BLKmode value;
2940 0 if value not BLKmode. */
2942 /* Nonzero if that address is being passed by treating it as
2943 an extra, implicit first parameter. Otherwise,
2944 it is passed by being copied directly into struct_value_rtx. */
2946 /* Holds the value of implicit argument for the struct value. */
2948 /* Size of aggregate value wanted, or zero if none wanted
2949 or if we are using the non-reentrant PCC calling convention
2950 or expecting the value in registers. */
2952 /* Nonzero if called function returns an aggregate in memory PCC style,
2953 by returning the address of where to find it. */
2957 /* Number of actual parameters in this call, including struct value addr. */
2959 /* Number of named args. Args after this are anonymous ones
2960 and they must all go on the stack. */
2962 /* Number of complex actual arguments that need to be split. */
2965 /* Vector of information about each argument.
2966 Arguments are numbered in the order they will be pushed,
2967 not the order they are written. */
2970 /* Total size in bytes of all the stack-parms scanned so far. */
2973 /* Size of arguments before any adjustments (such as rounding). */
2975 /* Data on reg parms scanned so far. */
2976 CUMULATIVE_ARGS args_so_far_v;
2977 cumulative_args_t args_so_far;
2978 /* Nonzero if a reg parm has been scanned. */
2980 /* Nonzero if this is an indirect function call. */
2982 /* Nonzero if we must avoid push-insns in the args for this call.
2983 If stack space is allocated for register parameters, but not by the
2984 caller, then it is preallocated in the fixed part of the stack frame.
2985 So the entire argument block must then be preallocated (i.e., we
2986 ignore PUSH_ROUNDING in that case). */
2990 /* Size of the stack reserved for parameter registers. */
2993 /* Address of space preallocated for stack parms
2994 (on machines that lack push insns), or 0 if space not preallocated. */
2997 /* Mask of ECF_ and ERF_ flags. */
3000 #ifdef REG_PARM_STACK_SPACE
3001 /* Define the boundary of the register parm stack space that needs to be
3002 saved, if any. */
3005 #endif
3013 /* State variables to track stack modifications. */
3019 /* Some stack pointer alterations we make are performed via
3020 allocate_dynamic_stack_space. This modifies the stack_pointer_delta,
3021 which we then also need to save/restore along the way. */
3024 rtx call_fusage;
3027 /* The alignment of the stack, in bits. */
3029 /* The alignment of the stack, in bytes. */
3031 /* The static chain value to use for this call. */
3032 rtx static_chain_value;
3033 /* See if this is "nothrow" function call. */
3037 /* See if we can find a DECL-node for the actual function, and get the
3038 function attributes (flags) from the function decl or type node. */
3041 {
3045 }
3046 else
3047 {
3052 }
3057 /* Warn if this value is an aggregate type,
3058 regardless of which calling convention we are using for it. */
3062 /* If the result of a non looping pure or const function call is
3063 ignored (or void), and none of its arguments are volatile, we can
3064 avoid expanding the call and just evaluate the arguments for
3065 side-effects. */
3070 {
3072 tree arg;
3073 call_expr_arg_iterator iter;
3077 {
3080 }
3083 {
3087 }
3088 }
3090 #ifdef REG_PARM_STACK_SPACE
3092 #endif
3098 /* Set up a place to return a structure. */
3100 /* Cater to broken compilers. */
3102 {
3103 /* This call returns a big structure. */
3106 #ifdef PCC_STATIC_STRUCT_RETURN
3107 {
3109 }
3111 {
3114 /* Even if it is semantically safe to use the target as the return
3115 slot, it may be not sufficiently aligned for the return type. */
3117 && target
3123 else
3124 {
3125 /* For variable-sized objects, we must be called with a target
3126 specified. If we were to allocate space on the stack here,
3127 we would have no way of knowing when to free it. */
3131 }
3132 }
3134 }
3136 /* Figure out the amount to which the stack should be aligned. */
3139 {
3141 /* Without automatic stack alignment, we can't increase preferred
3142 stack boundary. With automatic stack alignment, it is
3143 unnecessary since unless we can guarantee that all callers will
3144 align the outgoing stack properly, callee has to align its
3145 stack anyway. */
3150 }
3152 /* Operand 0 is a pointer-to-function; get the type of the function. */
3157 /* Count whether there are actual complex arguments that need to be split
3158 into their real and imaginary parts. Munge the type_arg_types
3159 appropriately here as well. */
3161 {
3162 call_expr_arg_iterator iter;
3163 tree arg;
3165 {
3169 num_complex_actuals++;
3170 }
3172 }
3173 else
3179 /* If struct_value_rtx is 0, it means pass the address
3180 as if it were an extra parameter. Put the argument expression
3181 in structure_value_addr_value. */
3183 {
3184 /* If structure_value_addr is a REG other than
3185 virtual_outgoing_args_rtx, we can use always use it. If it
3186 is not a REG, we must always copy it into a register.
3187 If it is virtual_outgoing_args_rtx, we must copy it to another
3188 register in some cases. */
3190 || (ACCUMULATE_OUTGOING_ARGS
3191 && stack_arg_under_construction
3197 structure_value_addr_value =
3200 }
3202 /* Count the arguments and set NUM_ACTUALS. */
3203 num_actuals =
3206 /* Compute number of named args.
3207 First, do a raw count of the args for INIT_CUMULATIVE_ARGS. */
3210 n_named_args
3212 /* Count the struct value address, if it is passed as a parm. */
3214 else
3215 /* If we know nothing, treat all args as named. */
3218 /* Start updating where the next arg would go.
3220 On some machines (such as the PA) indirect calls have a different
3221 calling convention than normal calls. The fourth argument in
3222 INIT_CUMULATIVE_ARGS tells the backend if this is an indirect call
3223 or not. */
3227 /* Now possibly adjust the number of named args.
3228 Normally, don't include the last named arg if anonymous args follow.
3229 We do include the last named arg if
3230 targetm.calls.strict_argument_naming() returns nonzero.
3231 (If no anonymous args follow, the result of list_length is actually
3232 one too large. This is harmless.)
3234 If targetm.calls.pretend_outgoing_varargs_named() returns
3235 nonzero, and targetm.calls.strict_argument_naming() returns zero,
3236 this machine will be able to place unnamed args that were passed
3237 in registers into the stack. So treat all args as named. This
3238 allows the insns emitting for a specific argument list to be
3239 independent of the function declaration.
3241 If targetm.calls.pretend_outgoing_varargs_named() returns zero,
3242 we do not have any reliable way to pass unnamed args in
3243 registers, so we must force them into memory. */
3247 ;
3250 /* Don't include the last named arg. */
3252 else
3253 /* Treat all args as named. */
3256 /* Make a vector to hold all the information about each arg. */
3259 /* Build up entries in the ARGS array, compute the size of the
3260 arguments into ARGS_SIZE, etc. */
3272 /* Now make final decision about preallocating stack space. */
3277 /* If the structure value address will reference the stack pointer, we
3278 must stabilize it. We don't need to do this if we know that we are
3279 not going to adjust the stack pointer in processing this call. */
3284 structure_value_addr))
3289 /* Tail calls can make things harder to debug, and we've traditionally
3290 pushed these optimizations into -O2. Don't try if we're already
3291 expanding a call, as that means we're an argument. Don't try if
3292 there's cleanups, as we know there's code to follow the call. */
3295 || !flag_optimize_sibling_calls
3300 /* If the user has marked the function as requiring tail-call
3301 optimization, attempt it. */
3305 /* Rest of purposes for tail call optimizations to fail. */
3308 structure_value_addr,
3309 funtype,
3310 reg_parm_stack_space,
3311 fndecl,
3314 /* Check if caller and callee disagree in promotion of function
3315 return value. */
3317 {
3327 caller_promoted_mode
3331 callee_promoted_mode
3341 {
3344 "caller and callee disagree in"
3345 " promotion of function"
3347 }
3348 }
3350 /* Ensure current function's preferred stack boundary is at least
3351 what we need. Stack alignment may also increase preferred stack
3352 boundary. */
3355 else
3360 /* We want to make two insn chains; one for a sibling call, the other
3361 for a normal call. We will select one of the two chains after
3362 initial RTL generation is complete. */
3364 {
3366 /* We want to emit any pending stack adjustments before the tail
3367 recursion "call". That way we know any adjustment after the tail
3368 recursion call can be ignored if we indeed use the tail
3369 call expansion. */
3370 saved_pending_stack_adjust save;
3372 rtx next_arg_reg;
3375 {
3376 /* State variables we need to save and restore between
3377 iterations. */
3379 }
3382 else
3385 /* Other state variables that we must reinitialize each time
3386 through the loop (that are not initialized by the loop itself). */
3390 /* Start a new sequence for the normal call case.
3392 From this point on, if the sibling call fails, we want to set
3393 sibcall_failure instead of continuing the loop. */
3396 /* Don't let pending stack adjusts add up to too much.
3397 Also, do all pending adjustments now if there is any chance
3398 this might be a call to alloca or if we are expanding a sibling
3399 call sequence.
3400 Also do the adjustments before a throwing call, otherwise
3401 exception handling can fail; PR 19225. */
3410 /* Precompute any arguments as needed. */
3414 /* Now we are about to start emitting insns that can be deleted
3415 if a libcall is deleted. */
3425 /* Compute the actual size of the argument block required. The variable
3426 and constant sizes must be combined, the size may have to be rounded,
3427 and there may be a minimum required size. When generating a sibcall
3428 pattern, do not round up, since we'll be re-using whatever space our
3429 caller provided. */
3430 unadjusted_args_size
3439 /* The argument block when performing a sibling call is the
3440 incoming argument block. */
3442 {
3445 argblock
3447 else
3448 argblock
3453 }
3455 /* If we have no actual push instructions, or shouldn't use them,
3456 make space for all args right now. */
3458 {
3460 {
3465 /* stack_arg_under_construction says whether a stack arg is
3466 being constructed at the old stack level. Pushing the stack
3467 gets a clean outgoing argument block. */
3470 }
3474 }
3475 else
3476 {
3477 /* Note that we must go through the motions of allocating an argument
3478 block even if the size is zero because we may be storing args
3479 in the area reserved for register arguments, which may be part of
3480 the stack frame. */
3484 /* Store the maximum argument space used. It will be pushed by
3485 the prologue (if ACCUMULATE_OUTGOING_ARGS, or stack overflow
3486 checking). */
3492 {
3494 {
3495 /* Since the stack pointer will never be pushed, it is
3496 possible for the evaluation of a parm to clobber
3497 something we have already written to the stack.
3498 Since most function calls on RISC machines do not use
3499 the stack, this is uncommon, but must work correctly.
3501 Therefore, we save any area of the stack that was already
3502 written and that we are using. Here we set up to do this
3503 by making a new stack usage map from the old one. The
3504 actual save will be done by store_one_arg.
3506 Another approach might be to try to reorder the argument
3507 evaluations to avoid this conflicting stack usage. */
3509 /* Since we will be writing into the entire argument area,
3510 the map must be allocated for its entire size, not just
3511 the part that is the responsibility of the caller. */
3516 highest_outgoing_arg_in_use
3518 else
3519 highest_outgoing_arg_in_use
3528 initial_highest_arg_in_use);
3532 (highest_outgoing_arg_in_use
3536 /* The address of the outgoing argument list must not be
3537 copied to a register here, because argblock would be left
3538 pointing to the wrong place after the call to
3539 allocate_dynamic_stack_space below. */
3542 }
3543 else
3544 {
3546 {
3547 /* Try to reuse some or all of the pending_stack_adjust
3548 to get this space. */
3549 needed
3550 = (combine_pending_stack_adjustment_and_call
3553 preferred_unit_stack_boundary));
3555 /* combine_pending_stack_adjustment_and_call computes
3556 an adjustment before the arguments are allocated.
3557 Account for them and see whether or not the stack
3558 needs to go up or down. */
3562 {
3563 /* We're releasing stack space. */
3564 /* ??? We can avoid any adjustment at all if we're
3565 already aligned. FIXME. */
3569 }
3570 else
3571 /* We need to allocate space. We'll do that in
3572 push_block below. */
3574 }
3576 /* Special case this because overhead of `push_block' in
3577 this case is non-trivial. */
3580 else
3581 {
3585 }
3587 /* We only really need to call `copy_to_reg' in the case
3588 where push insns are going to be used to pass ARGBLOCK
3589 to a function call in ARGS. In that case, the stack
3590 pointer changes value from the allocation point to the
3591 call point, and hence the value of
3592 VIRTUAL_OUTGOING_ARGS_RTX changes as well. But might
3593 as well always do it. */
3595 }
3596 }
3597 }
3600 {
3601 /* The save/restore code in store_one_arg handles all
3602 cases except one: a constructor call (including a C
3603 function returning a BLKmode struct) to initialize
3604 an argument. */
3606 {
3607 rtx push_size
3613 {
3618 /* stack_arg_under_construction says whether a stack
3619 arg is being constructed at the old stack level.
3620 Pushing the stack gets a clean outgoing argument
3621 block. */
3622 old_stack_arg_under_construction
3625 /* Make a new map for the new argument list. */
3630 }
3631 /* We can pass TRUE as the 4th argument because we just
3632 saved the stack pointer and will restore it right after
3633 the call. */
3636 }
3638 /* If argument evaluation might modify the stack pointer,
3639 copy the address of the argument list to a register. */
3642 {
3645 }
3646 }
3650 /* Stack is properly aligned, pops can't safely be deferred during
3651 the evaluation of the arguments. */
3652 NO_DEFER_POP;
3654 /* Precompute all register parameters. It isn't safe to compute
3655 anything once we have started filling any specific hard regs.
3656 TLS symbols sometimes need a call to resolve. Precompute
3657 register parameters before any stack pointer manipulation
3658 to avoid unaligned stack in the called function. */
3661 OK_DEFER_POP;
3663 /* Perform stack alignment before the first push (the last arg). */
3667 {
3668 /* When the stack adjustment is pending, we get better code
3669 by combining the adjustments. */
3672 {
3673 pending_stack_adjust
3674 = (combine_pending_stack_adjustment_and_call
3677 preferred_unit_stack_boundary));
3679 }
3683 }
3684 /* Now that the stack is properly aligned, pops can't safely
3685 be deferred during the evaluation of the arguments. */
3686 NO_DEFER_POP;
3688 /* Record the maximum pushed stack space size. We need to delay
3689 doing it this far to take into account the optimization done
3690 by combine_pending_stack_adjustment_and_call. */
3692 && !ACCUMULATE_OUTGOING_ARGS
3693 && pass
3695 {
3699 }
3705 else
3708 #ifdef REG_PARM_STACK_SPACE
3709 /* Save the fixed argument area if it's part of the caller's frame and
3710 is clobbered by argument setup for this call. */
3714 #endif
3716 /* Now store (and compute if necessary) all non-register parms.
3717 These come before register parms, since they can require block-moves,
3718 which could clobber the registers used for register parms.
3719 Parms which have partial registers are not stored here,
3720 but we do preallocate space here if they want that. */
3723 {
3724 /* Delay bounds until all other args are stored. */
3728 {
3731 /* We don't allow passing huge (> 2^30 B) arguments
3732 by value. It would cause an overflow later on. */
3735 {
3738 }
3742 reg_parm_stack_space)
3747 }
3750 call_fusage
3753 call_fusage);
3754 }
3756 /* If we have a parm that is passed in registers but not in memory
3757 and whose alignment does not permit a direct copy into registers,
3758 make a group of pseudos that correspond to each register that we
3759 will later fill. */
3763 /* Now store any partially-in-registers parm.
3764 This is the last place a block-move can happen. */
3768 {
3771 /* On targets with weird calling conventions (e.g. PA) it's
3772 hard to ensure that all cases of argument overlap between
3773 stack and registers work. Play it safe and bail out. */
3775 {
3778 }
3782 reg_parm_stack_space)
3787 }
3792 {
3795 }
3799 /* Figure out the register where the value, if any, will come back. */
3804 {
3806 {
3813 }
3814 else
3815 {
3820 fndecl,
3822 }
3824 /* If VALREG is a PARALLEL whose first member has a zero
3825 offset, use that. This is for targets such as m68k that
3826 return the same value in multiple places. */
3828 {
3835 }
3836 }
3838 /* Store all bounds not passed in registers. */
3840 {
3845 ? NULL
3847 }
3849 /* If register arguments require space on the stack and stack space
3850 was not preallocated, allocate stack space here for arguments
3851 passed in registers. */
3853 && !ACCUMULATE_OUTGOING_ARGS
3857 /* Pass the function the address in which to return a
3858 structure value. */
3860 {
3861 structure_value_addr
3866 NULL_RTX)));
3870 }
3880 /* Save a pointer to the last insn before the call, so that we can
3881 later safely search backwards to find the CALL_INSN. */
3884 /* Set up next argument register. For sibling calls on machines
3885 with register windows this should be the incoming register. */
3888 VOIDmode,
3889 void_type_node,
3891 else
3897 {
3903 && valreg
3906 call_fusage
3909 call_fusage);
3910 }
3911 /* All arguments and registers used for the call must be set up by
3912 now! */
3914 /* Stack must be properly aligned now. */
3918 /* Generate the actual call instruction. */
3925 {
3929 {
3933 }
3936 }
3938 /* If the call setup or the call itself overlaps with anything
3939 of the argument setup we probably clobbered our call address.
3940 In that case we can't do sibcalls. */
3945 /* If a non-BLKmode value is returned at the most significant end
3946 of a register, shift the register right by the appropriate amount
3947 and update VALREG accordingly. BLKmode values are handled by the
3948 group load/store machinery below. */
3950 && !pcc_struct_value
3955 {
3959 }
3962 {
3966 /* The return value from a malloc-like function is a pointer. */
3972 /* The return value from a malloc-like function can not alias
3973 anything else. */
3977 /* Write out the sequence. */
3982 }
3984 /* For calls to `setjmp', etc., inform
3985 function.c:setjmp_warnings that it should complain if
3986 nonvolatile values are live. For functions that cannot
3987 return, inform flow that control does not fall through. */
3990 {
3991 /* The barrier must be emitted
3992 immediately after the CALL_INSN. Some ports emit more
3993 than just a CALL_INSN above, so we must search for it here. */
3997 {
3999 /* There was no CALL_INSN? */
4001 }
4005 /* Stack adjustments after a noreturn call are dead code.
4006 However when NO_DEFER_POP is in effect, we must preserve
4007 stack_pointer_delta. */
4009 {
4012 }
4013 }
4015 /* If value type not void, return an rtx for the value. */
4021 {
4023 {
4024 target
4027 structure_value_addr));
4029 }
4030 }
4032 {
4033 /* This is the special C++ case where we need to
4034 know what the true target was. We take care to
4035 never use this value more than once in one expression. */
4039 }
4040 /* Handle calls that return values in multiple non-contiguous locations.
4041 The Irix 6 ABI has examples of this. */
4043 {
4047 ;
4049 /* Handle the result of a emit_group_move_into_temps
4050 call in the previous pass. */
4052 else
4055 }
4059 {
4062 /* We have to copy a return value in a CLASS_LIKELY_SPILLED hard
4063 reg to a plain register. */
4067 /* If TARGET is a MEM in the argument area, and we have
4068 saved part of the argument area, then we can't store
4069 directly into TARGET as it may get overwritten when we
4070 restore the argument save area below. Don't work too
4071 hard though and simply force TARGET to a register if it
4072 is a MEM; the optimizer is quite likely to sort it out. */
4076 {
4079 }
4083 else
4084 {
4085 /* TARGET and VALREG cannot be equal at this point
4086 because the latter would not have
4087 REG_FUNCTION_VALUE_P true, while the former would if
4088 it were referring to the same register.
4090 If they refer to the same register, this move will be
4091 a no-op, except when function inlining is being
4092 done. */
4095 /* If we are setting a MEM, this code must be executed.
4096 Since it is emitted after the call insn, sibcall
4097 optimization cannot be performed in that case. */
4100 }
4101 }
4102 else
4105 /* If we promoted this return value, make the proper SUBREG.
4106 TARGET might be const0_rtx here, so be careful. */
4110 {
4113 machine_mode pmode;
4115 /* Ensure we promote as expected, and get the new unsignedness. */
4125 }
4127 /* If size of args is variable or this was a constructor call for a stack
4128 argument, restore saved stack-pointer value. */
4131 {
4145 }
4147 {
4148 #ifdef REG_PARM_STACK_SPACE
4152 #endif
4154 /* If we saved any argument areas, restore them. */
4157 {
4159 rtx stack_area
4166 else
4169 BLOCK_OP_CALL_PARM);
4170 }
4174 }
4176 /* If this was alloca, record the new stack level. */
4180 /* Free up storage we no longer need. */
4190 {
4193 /* Restore the pending stack adjustment now that we have
4194 finished generating the sibling call sequence. */
4198 /* Prepare arg structure for next iteration. */
4200 {
4204 }
4209 }
4210 else
4211 {
4214 /* Verify that we've deallocated all the stack we used. */
4216 || (old_stack_allocated
4218 }
4220 /* If something prevents making this a sibling call,
4221 zero out the sequence. */
4224 else
4226 }
4228 /* If tail call production succeeded, we need to remove REG_EQUIV notes on
4229 arguments too, as argument area is now clobbered by the call. */
4231 {
4234 }
4235 else
4236 {
4239 /* Ideally we'd emit a message for all of the ways that it could
4240 have failed. */
4242 }
4244 currently_expanding_call--;
4249 /* Join result with returned bounds so caller may use them if needed. */
4253 }
4255 /* A sibling call sequence invalidates any REG_EQUIV notes made for
4256 this function's incoming arguments.
4258 At the start of RTL generation we know the only REG_EQUIV notes
4259 in the rtl chain are those for incoming arguments, so we can look
4260 for REG_EQUIV notes between the start of the function and the
4261 NOTE_INSN_FUNCTION_BEG.
4263 This is (slight) overkill. We could keep track of the highest
4264 argument we clobber and be more selective in removing notes, but it
4265 does not seem to be worth the effort. */
4267 void
4269 {
4273 {
4274 rtx note;
4276 /* There are never REG_EQUIV notes for the incoming arguments
4277 after the NOTE_INSN_FUNCTION_BEG note, so stop if we see it. */
4287 }
4288 }
4290 /* Traverse a list of TYPES and expand all complex types into their
4291 components. */
4292 static tree
4294 {
4295 tree p;
4297 /* Before allocating memory, check for the common case of no complex. */
4299 {
4304 }
4307 found:
4311 {
4316 {
4319 /* Rewrite complex type with component type. */
4323 /* Add another component type for the imaginary part. */
4328 /* Skip the newly created node. */
4330 }
4331 }
4334 }
4335 \f
4336 /* Output a library call to function ORGFUN (a SYMBOL_REF rtx)
4337 for a value of mode OUTMODE,
4338 with NARGS different arguments, passed as ARGS.
4339 Store the return value if RETVAL is nonzero: store it in VALUE if
4340 VALUE is nonnull, otherwise pick a convenient location. In either
4341 case return the location of the stored value.
4343 FN_TYPE should be LCT_NORMAL for `normal' calls, LCT_CONST for
4344 `const' calls, LCT_PURE for `pure' calls, or another LCT_ value for
4345 other types of library calls. */
4347 rtx
4351 {
4352 /* Total size in bytes of all the stack-parms scanned so far. */
4354 /* Size of arguments before any adjustments (such as rounding). */
4357 rtx fun;
4358 /* Todo, choose the correct decl type of orgfun. Sadly this information
4359 isn't present here, so we default to native calling abi here. */
4364 CUMULATIVE_ARGS args_so_far_v;
4365 cumulative_args_t args_so_far;
4366 struct arg
4367 {
4368 rtx value;
4369 machine_mode mode;
4370 rtx reg;
4373 rtx save_area;
4374 };
4379 rtx valreg;
4389 #ifdef REG_PARM_STACK_SPACE
4390 /* Define the boundary of the register parm stack space that needs to be
4391 save, if any. */
4394 #endif
4396 /* Size of the stack reserved for parameter registers. */
4403 #ifdef REG_PARM_STACK_SPACE
4405 #endif
4407 /* By default, library functions cannot throw. */
4411 {
4429 }
4432 /* Ensure current function's preferred stack boundary is at least
4433 what we need. */
4437 /* If this kind of value comes back in memory,
4438 decide where in memory it should come back. */
4440 {
4443 {
4444 #ifdef PCC_STATIC_STRUCT_RETURN
4445 rtx pointer_reg
4455 else
4457 #endif
4458 /* This call returns a big structure. */
4460 }
4461 }
4462 else
4465 /* ??? Unfinished: must pass the memory address as an argument. */
4467 /* Copy all the libcall-arguments out of the varargs data
4468 and into a vector ARGVEC.
4470 Compute how to pass each argument. We only support a very small subset
4471 of the full argument passing conventions to limit complexity here since
4472 library functions shouldn't have many args. */
4477 #ifdef INIT_CUMULATIVE_LIBCALL_ARGS
4479 #else
4481 #endif
4491 /* If there's a structure value address to be passed,
4492 either pass it in the special place, or pass it as an extra argument. */
4494 {
4497 nargs++;
4499 /* Make sure it is a reasonable operand for a move or push insn. */
4515 #ifdef STACK_PARMS_IN_REG_PARM_AREA
4517 #else
4519 #endif
4529 count++;
4530 }
4533 {
4538 /* We cannot convert the arg value to the mode the library wants here;
4539 must do it earlier where we know the signedness of the arg. */
4543 /* Make sure it is a reasonable operand for a move or push insn. */
4549 {
4550 rtx slot;
4551 int must_copy
4554 /* If this was a CONST function, it is now PURE since it now
4555 reads memory. */
4557 {
4560 }
4563 {
4568 }
4569 else
4570 {
4574 }
4578 call_fusage);
4582 slot),
4583 call_fusage);
4587 }
4601 {
4603 #ifdef STACK_PARMS_IN_REG_PARM_AREA
4605 #else
4607 #endif
4612 }
4613 #ifdef BLOCK_REG_PADDING
4614 else
4615 /* The argument is passed entirely in registers. See at which
4616 end it should be padded. */
4620 #endif
4623 }
4625 /* If this machine requires an external definition for library
4626 functions, write one out. */
4631 + stack_pointer_delta
4633 / STACK_BYTES
4638 reg_parm_stack_space);
4647 {
4651 }
4654 {
4655 /* Since the stack pointer will never be pushed, it is possible for
4656 the evaluation of a parm to clobber something we have already
4657 written to the stack. Since most function calls on RISC machines
4658 do not use the stack, this is uncommon, but must work correctly.
4660 Therefore, we save any area of the stack that was already written
4661 and that we are using. Here we set up to do this by making a new
4662 stack usage map from the old one.
4664 Another approach might be to try to reorder the argument
4665 evaluations to avoid this conflicting stack usage. */
4669 /* Since we will be writing into the entire argument area, the
4670 map must be allocated for its entire size, not just the part that
4671 is the responsibility of the caller. */
4678 else
4686 initial_highest_arg_in_use);
4693 /* We must be careful to use virtual regs before they're instantiated,
4694 and real regs afterwards. Loop optimization, for example, can create
4695 new libcalls after we've instantiated the virtual regs, and if we
4696 use virtuals anyway, they won't match the rtl patterns. */
4700 STACK_POINTER_OFFSET);
4701 else
4703 }
4704 else
4705 {
4708 }
4710 /* We push args individually in reverse order, perform stack alignment
4711 before the first push (the last arg). */
4718 #ifdef REG_PARM_STACK_SPACE
4720 {
4721 /* The argument list is the property of the called routine and it
4722 may clobber it. If the fixed area has been used for previous
4723 parameters, we must save and restore it. */
4726 }
4727 #endif
4729 /* When expanding a normal call, args are stored in push order,
4730 which is the reverse of what we have here. */
4734 {
4737 }
4741 /* Push the args that need to be pushed. */
4745 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
4746 are to be pushed. */
4748 {
4757 {
4758 rtx use;
4761 {
4762 /* If this is being stored into a pre-allocated, fixed-size,
4763 stack area, save any previous data at that location. */
4766 {
4767 /* stack_slot is negative, but we want to index stack_usage_map
4768 with positive values. */
4771 }
4772 else
4773 {
4776 }
4779 /* Don't worry about things in the fixed argument area;
4780 it has already been saved. */
4784 i++;
4787 {
4788 /* We need to make a save area. */
4789 unsigned int size
4791 machine_mode save_mode
4793 rtx adr
4796 rtx stack_area
4800 {
4804 );
4808 stack_area,
4810 BLOCK_OP_CALL_PARM);
4811 }
4812 else
4813 {
4817 }
4818 }
4819 }
4824 reg_parm_stack_space,
4827 /* Now mark the segment we just used. */
4832 NO_DEFER_POP;
4834 /* Indicate argument access so that alias.c knows that these
4835 values are live. */
4841 else
4842 {
4843 /* When arguments are pushed, trying to tell alias.c where
4844 exactly this argument is won't work, because the
4845 auto-increment causes confusion. So we merely indicate
4846 that we access something with a known mode somewhere on
4847 the stack. */
4851 }
4855 }
4856 }
4862 /* Now load any reg parms into their regs. */
4864 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
4865 are to be pushed. */
4867 {
4872 #ifdef BLOCK_REG_PADDING
4874 #endif
4876 /* Handle calls that pass values in multiple non-contiguous
4877 locations. The PA64 has examples of this for library calls. */
4881 {
4883 #ifdef BLOCK_REG_PADDING
4886 /* Copied from load_register_parameters. */
4888 /* Handle case where we have a value that needs shifting
4889 up to the msb. eg. a QImode value and we're padding
4890 upward on a BYTES_BIG_ENDIAN machine. */
4894 {
4895 rtx x;
4898 /* Assigning REG here rather than a temp makes CALL_FUSAGE
4899 report the whole reg as used. Strictly speaking, the
4900 call only uses SIZE bytes at the msb end, but it doesn't
4901 seem worth generating rtl to say that. */
4906 }
4907 #endif
4908 }
4910 NO_DEFER_POP;
4911 }
4913 /* Any regs containing parms remain in use through the call. */
4915 {
4920 {
4923 {
4928 }
4929 else
4931 }
4932 }
4934 /* Pass the function the address in which to return a structure value. */
4936 {
4940 NULL_RTX)));
4943 }
4945 /* Don't allow popping to be deferred, since then
4946 cse'ing of library calls could delete a call and leave the pop. */
4947 NO_DEFER_POP;
4951 /* Stack must be properly aligned now. */
4957 /* We pass the old value of inhibit_defer_pop + 1 to emit_call_1, which
4958 will set inhibit_defer_pop to that value. */
4959 /* The return type is needed to decide how many bytes the function pops.
4960 Signedness plays no role in that, so for simplicity, we pretend it's
4961 always signed. We also assume that the list of arguments passed has
4962 no impact, so we pretend it is unknown. */
4968 struct_value_size,
4971 valreg,
4975 {
4980 }
4982 /* Right-shift returned value if necessary. */
4986 {
4989 }
4993 /* For calls to `setjmp', etc., inform function.c:setjmp_warnings
4994 that it should complain if nonvolatile values are live. For
4995 functions that cannot return, inform flow that control does not
4996 fall through. */
4998 {
4999 /* The barrier note must be emitted
5000 immediately after the CALL_INSN. Some ports emit more than
5001 just a CALL_INSN above, so we must search for it here. */
5004 {
5006 /* There was no CALL_INSN? */
5008 }
5011 }
5013 /* Consider that "regular" libcalls, i.e. all of them except for LCT_THROW
5014 and LCT_RETURNS_TWICE, cannot perform non-local gotos. */
5016 {
5019 {
5021 /* There was no CALL_INSN? */
5023 }
5026 }
5028 /* Now restore inhibit_defer_pop to its actual original value. */
5029 OK_DEFER_POP;
5033 /* Copy the value to the right place. */
5035 {
5037 {
5042 }
5044 {
5048 }
5049 else
5050 {
5051 /* Convert to the proper mode if a promotion has been active. */
5053 {
5060 }
5064 else
5066 }
5067 }
5070 {
5071 #ifdef REG_PARM_STACK_SPACE
5075 #endif
5077 /* If we saved any argument areas, restore them. */
5080 {
5089 validize_mem
5092 BLOCK_OP_CALL_PARM);
5093 else
5095 }
5099 }
5105 }
5106 \f
5108 /* Store pointer bounds argument ARG into Bounds Table entry
5109 associated with PARM. */
5110 static void
5112 {
5115 /* We may pass bounds not associated with any pointer. */
5117 {
5121 }
5122 /* Find pointer associated with bounds and where it is
5123 passed. */
5124 else
5125 {
5127 {
5131 }
5133 {
5141 else
5142 {
5145 }
5146 }
5147 else
5148 {
5157 else
5159 }
5160 }
5162 /* Expand bounds. */
5167 }
5169 /* Store a single argument for a function call
5170 into the register or memory area where it must be passed.
5171 *ARG describes the argument value and where to pass it.
5173 ARGBLOCK is the address of the stack-block for all the arguments,
5174 or 0 on a machine where arguments are pushed individually.
5176 MAY_BE_ALLOCA nonzero says this could be a call to `alloca'
5177 so must be careful about how the stack is used.
5179 VARIABLE_SIZE nonzero says that this was a variable-sized outgoing
5180 argument stack. This is used if ACCUMULATE_OUTGOING_ARGS to indicate
5181 that we need not worry about saving and restoring the stack.
5183 FNDECL is the declaration of the function we are calling.
5185 Return nonzero if this arg should cause sibcall failure,
5186 zero otherwise. */
5188 static int
5191 {
5202 /* Push a new temporary level for any temporaries we make for
5203 this argument. */
5207 {
5208 /* If this is being stored into a pre-allocated, fixed-size, stack area,
5209 save any previous data at that location. */
5211 {
5213 {
5214 /* stack_slot is negative, but we want to index stack_usage_map
5215 with positive values. */
5218 else
5222 }
5223 else
5224 {
5227 else
5231 }
5234 /* Don't worry about things in the fixed argument area;
5235 it has already been saved. */
5239 i++;
5242 {
5243 /* We need to make a save area. */
5245 machine_mode save_mode
5251 {
5252 arg->save_area
5256 stack_area,
5258 BLOCK_OP_CALL_PARM);
5259 }
5260 else
5261 {
5264 }
5265 }
5266 }
5267 }
5269 /* If this isn't going to be placed on both the stack and in registers,
5270 set up the register and number of words. */
5272 {
5275 else
5278 }
5280 /* Being passed entirely in a register. We shouldn't be called in
5281 this case. */
5284 /* If this arg needs special alignment, don't load the registers
5285 here. */
5289 /* If this is being passed partially in a register, we can't evaluate
5290 it directly into its stack slot. Otherwise, we can. */
5292 {
5293 /* stack_arg_under_construction is nonzero if a function argument is
5294 being evaluated directly into the outgoing argument list and
5295 expand_call must take special action to preserve the argument list
5296 if it is called recursively.
5298 For scalar function arguments stack_usage_map is sufficient to
5299 determine which stack slots must be saved and restored. Scalar
5300 arguments in general have pass_on_stack == 0.
5302 If this argument is initialized by a function which takes the
5303 address of the argument (a C++ constructor or a C function
5304 returning a BLKmode structure), then stack_usage_map is
5305 insufficient and expand_call must push the stack around the
5306 function call. Such arguments have pass_on_stack == 1.
5308 Note that it is always safe to set stack_arg_under_construction,
5309 but this generates suboptimal code if set when not needed. */
5312 stack_arg_under_construction++;
5315 (partial
5320 /* If we are promoting object (or for any other reason) the mode
5321 doesn't agree, convert the mode. */
5328 stack_arg_under_construction--;
5329 }
5331 /* Check for overlap with already clobbered argument area. */
5338 /* Don't allow anything left on stack from computation
5339 of argument to alloca. */
5344 /* If the value is already in the stack slot, we are done. */
5345 ;
5347 {
5351 /* Argument is a scalar, not entirely passed in registers.
5352 (If part is passed in registers, arg->partial says how much
5353 and emit_push_insn will take care of putting it there.)
5355 Push it, and if its size is less than the
5356 amount of space allocated to it,
5357 also bump stack pointer by the additional space.
5358 Note that in C the default argument promotions
5359 will prevent such mismatches. */
5362 /* Compute how much space the push instruction will push.
5363 On many machines, pushing a byte will advance the stack
5364 pointer by a halfword. */
5365 #ifdef PUSH_ROUNDING
5367 #endif
5370 /* Compute how much space the argument should get:
5371 round up to a multiple of the alignment for arguments. */
5378 /* Compute the alignment of the pushed argument. */
5382 {
5385 {
5388 }
5389 }
5391 /* This isn't already where we want it on the stack, so put it there.
5392 This can either be done with push or copy insns. */
5399 /* Unless this is a partially-in-register argument, the argument is now
5400 in the stack. */
5403 }
5404 else
5405 {
5406 /* BLKmode, at least partly to be pushed. */
5410 rtx size_rtx;
5412 /* Pushing a nonscalar.
5413 If part is passed in registers, PARTIAL says how much
5414 and emit_push_insn will take care of putting it there. */
5416 /* Round its size up to a multiple
5417 of the allocation unit for arguments. */
5420 {
5423 }
5424 else
5425 {
5426 /* PUSH_ROUNDING has no effect on us, because emit_push_insn
5427 for BLKmode is careful to avoid it. */
5433 EXPAND_NORMAL);
5434 }
5438 /* When an argument is padded down, the block is aligned to
5439 PARM_BOUNDARY, but the actual argument isn't. */
5442 {
5446 {
5449 }
5450 }
5453 {
5454 /* emit_push_insn might not work properly if arg->value and
5455 argblock + arg->locate.offset areas overlap. */
5464 {
5468 /* arg.locate doesn't contain the pretend_args_size offset,
5469 it's part of argblock. Ensure we don't count it in I. */
5472 else
5475 /* expand_call should ensure this. */
5481 {
5484 }
5486 {
5487 /* Use arg->locate.size.constant instead of size_rtx
5488 because we only care about the part of the argument
5489 on the stack. */
5493 }
5494 else
5495 {
5496 /* Even though they appear to be at the same location,
5497 if part of the outgoing argument is in registers,
5498 they aren't really at the same location. Check for
5499 this by making sure that the incoming size is the
5500 same as the outgoing size. */
5503 }
5504 }
5505 }
5512 /* Unless this is a partially-in-register argument, the argument is now
5513 in the stack.
5515 ??? Unlike the case above, in which we want the actual
5516 address of the data, so that we can load it directly into a
5517 register, here we want the address of the stack slot, so that
5518 it's properly aligned for word-by-word copying or something
5519 like that. It's not clear that this is always correct. */
5522 }
5525 {
5527 arg->parallel_value
5530 }
5532 /* Mark all slots this store used. */
5538 /* Once we have pushed something, pops can't safely
5539 be deferred during the rest of the arguments. */
5540 NO_DEFER_POP;
5542 /* Free any temporary slots made in processing this argument. */
5546 }
5548 /* Nonzero if we do not know how to pass TYPE solely in registers. */
5550 bool
5552 const_tree type)
5553 {
5557 /* If the type has variable size... */
5561 /* If the type is marked as addressable (it is required
5562 to be constructed into the stack)... */
5567 }
5569 /* Another version of the TARGET_MUST_PASS_IN_STACK hook. This one
5570 takes trailing padding of a structure into account. */
5571 /* ??? Should be able to merge these two by examining BLOCK_REG_PADDING. */
5573 bool
5575 {
5579 /* If the type has variable size... */
5583 /* If the type is marked as addressable (it is required
5584 to be constructed into the stack)... */
5588 /* If the padding and mode of the type is such that a copy into
5589 a register would put it into the wrong part of the register. */
5597 }
5599 /* Tell the garbage collector about GTY markers in this source file. */