| blob | d5bd5049cb94fd57aafe1b20bbe152d9f6880ddc |
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);
177 #ifdef REG_PARM_STACK_SPACE
180 #endif
181 \f
182 /* Force FUNEXP into a form suitable for the address of a CALL,
183 and return that as an rtx. Also load the static chain register
184 if FNDECL is a nested function.
186 CALL_FUSAGE points to a variable holding the prospective
187 CALL_INSN_FUNCTION_USAGE information. */
189 rtx
192 {
193 /* Make a valid memory address and copy constants through pseudo-regs,
194 but not for a constant address if -fno-function-cse. */
196 {
197 /* If it's an indirect call by descriptor, generate code to perform
198 runtime identification of the pointer and load the descriptor. */
200 {
205 fndecl_or_type
207 fndecl_or_type);
214 /* Avoid long live ranges around function calls. */
220 /* Emit the runtime identification pattern. */
223 call_lab);
225 /* Statically predict the branch to very likely taken. */
230 /* Load the descriptor. */
239 POINTER_SIZE / BITS_PER_UNIT
248 {
251 }
253 /* Make sure we're not going to be overwritten below. */
255 }
257 /* If we are using registers for parameters, force the
258 function address into a register now. */
259 funexp = ((reg_parm_seen
263 }
264 else
265 {
266 /* funexp could be a SYMBOL_REF represents a function pointer which is
267 of ptr_mode. In this case, it should be converted into address mode
268 to be a valid address for memory rtx pattern. See PR 64971. */
273 {
276 }
277 }
282 {
283 rtx chain;
290 {
293 }
294 }
297 }
299 /* Generate instructions to call function FUNEXP,
300 and optionally pop the results.
301 The CALL_INSN is the first insn generated.
303 FNDECL is the declaration node of the function. This is given to the
304 hook TARGET_RETURN_POPS_ARGS to determine whether this function pops
305 its own args.
307 FUNTYPE is the data type of the function. This is given to the hook
308 TARGET_RETURN_POPS_ARGS to determine whether this function pops its
309 own args. We used to allow an identifier for library functions, but
310 that doesn't work when the return type is an aggregate type and the
311 calling convention says that the pointer to this aggregate is to be
312 popped by the callee.
314 STACK_SIZE is the number of bytes of arguments on the stack,
315 ROUNDED_STACK_SIZE is that number rounded up to
316 PREFERRED_STACK_BOUNDARY; zero if the size is variable. This is
317 both to put into the call insn and to generate explicit popping
318 code if necessary.
320 STRUCT_VALUE_SIZE is the number of bytes wanted in a structure value.
321 It is zero if this call doesn't want a structure value.
323 NEXT_ARG_REG is the rtx that results from executing
324 targetm.calls.function_arg (&args_so_far, VOIDmode, void_type_node, true)
325 just after all the args have had their registers assigned.
326 This could be whatever you like, but normally it is the first
327 arg-register beyond those used for args in this call,
328 or 0 if all the arg-registers are used in this call.
329 It is passed on to `gen_call' so you can put this info in the call insn.
331 VALREG is a hard register in which a value is returned,
332 or 0 if the call does not return a value.
334 OLD_INHIBIT_DEFER_POP is the value that `inhibit_defer_pop' had before
335 the args to this call were processed.
336 We restore `inhibit_defer_pop' to that value.
338 CALL_FUSAGE is either empty or an EXPR_LIST of USE expressions that
339 denote registers used by the called function. */
341 static void
343 tree funtype ATTRIBUTE_UNUSED,
344 HOST_WIDE_INT stack_size ATTRIBUTE_UNUSED,
345 HOST_WIDE_INT rounded_stack_size,
346 HOST_WIDE_INT struct_value_size ATTRIBUTE_UNUSED,
349 cumulative_args_t args_so_far ATTRIBUTE_UNUSED)
350 {
356 /* Sibling call patterns never pop arguments (no sibcall(_value)_pop
357 patterns exist). Any popping that the callee does on return will
358 be from our caller's frame rather than ours. */
360 {
363 #ifdef CALL_POPS_ARGS
365 #endif
366 }
368 /* Ensure address is valid. SYMBOL_REF is already valid, so no need,
369 and we don't want to load it into a register as an optimization,
370 because prepare_call_address already did it if it should be done. */
376 {
379 /* Although a built-in FUNCTION_DECL and its non-__builtin
380 counterpart compare equal and get a shared mem_attrs, they
381 produce different dump output in compare-debug compilations,
382 if an entry gets garbage collected in one compilation, then
383 adds a different (but equivalent) entry, while the other
384 doesn't run the garbage collector at the same spot and then
385 shares the mem_attr with the equivalent entry. */
387 {
391 }
394 }
399 {
402 rounded_stack_size_rtx,
404 else
407 }
408 /* If the target has "call" or "call_value" insns, then prefer them
409 if no arguments are actually popped. If the target does not have
410 "call" or "call_value" insns, then we must use the popping versions
411 even if the call has no arguments to pop. */
413 || !(valreg
416 {
419 /* If this subroutine pops its own args, record that in the call insn
420 if possible, for the sake of frame pointer elimination. */
424 rounded_stack_size_rtx,
426 else
431 }
432 else
433 {
437 else
440 }
443 /* Find the call we just emitted. */
446 /* Some target create a fresh MEM instead of reusing the one provided
447 above. Set its MEM_EXPR. */
454 /* Mark instrumented calls. */
458 /* Put the register usage information there. */
461 /* If this is a const call, then set the insn's unchanging bit. */
465 /* If this is a pure call, then set the insn's unchanging bit. */
469 /* If this is a const call, then set the insn's unchanging bit. */
473 /* Create a nothrow REG_EH_REGION note, if needed. */
480 {
483 }
487 /* Restore this now, so that we do defer pops for this call's args
488 if the context of the call as a whole permits. */
492 {
504 /* If popup is needed, stack realign must use DRAP */
507 }
508 /* For noreturn calls when not accumulating outgoing args force
509 REG_ARGS_SIZE note to prevent crossjumping of calls with different
510 args sizes. */
515 {
516 /* If returning from the subroutine does not automatically pop the args,
517 we need an instruction to pop them sooner or later.
518 Perhaps do it now; perhaps just record how much space to pop later.
520 If returning from the subroutine does pop the args, indicate that the
521 stack pointer will be changed. */
524 {
526 /* Just pretend we did the pop. */
531 else
533 }
534 }
535 /* When we accumulate outgoing args, we must avoid any stack manipulations.
536 Restore the stack pointer to its original value now. Usually
537 ACCUMULATE_OUTGOING_ARGS targets don't get here, but there are exceptions.
538 On i386 ACCUMULATE_OUTGOING_ARGS can be enabled on demand, and
539 popping variants of functions exist as well.
541 ??? We may optimize similar to defer_pop above, but it is
542 probably not worthwhile.
544 ??? It will be worthwhile to enable combine_stack_adjustments even for
545 such machines. */
548 }
550 /* Determine if the function identified by FNDECL is one with
551 special properties we wish to know about. Modify FLAGS accordingly.
553 For example, if the function might return more than one time (setjmp), then
554 set ECF_RETURNS_TWICE.
556 Set ECF_MAY_BE_ALLOCA for any memory allocation function that might allocate
557 space from the stack such as alloca. */
559 static int
561 {
564 /* For instrumentation clones we want to derive flags
565 from the original name. */
572 /* Exclude functions not at the file scope, or not `extern',
573 since they are not the magic functions we would otherwise
574 think they are.
575 FIXME: this should be handled with attributes, not with this
576 hacky imitation of DECL_ASSEMBLER_NAME. It's (also) wrong
577 because you can declare fork() inside a function if you
578 wish. */
582 {
586 /* We assume that alloca will always be called by name. It
587 makes no sense to pass it as a pointer-to-function to
588 anything that does not understand its behavior. */
594 /* Disregard prefix _ or __. */
596 {
599 else
601 }
603 /* ECF_RETURNS_TWICE is safe even for -ffreestanding. */
610 }
614 {
621 }
624 }
626 /* Similar to special_function_p; return a set of ERF_ flags for the
627 function FNDECL. */
628 static int
630 {
631 tree attr;
645 {
658 }
659 }
661 /* Return nonzero when FNDECL represents a call to setjmp. */
663 int
665 {
669 }
672 /* Return true if STMT may be an alloca call. */
674 bool
676 {
677 tree fndecl;
687 }
689 /* Return true if STMT is a builtin alloca call. */
691 bool
693 {
694 tree fndecl;
702 {
708 }
711 }
713 /* Return true when exp contains a builtin alloca call. */
715 bool
717 {
718 tree fndecl;
723 {
729 }
732 }
734 /* Return TRUE if FNDECL is either a TM builtin or a TM cloned
735 function. Return FALSE otherwise. */
737 static bool
739 {
747 {
749 {
792 }
793 }
795 }
797 /* Detect flags (function attributes) from the function decl or type node. */
799 int
801 {
805 {
806 /* The function exp may have the `malloc' attribute. */
810 /* The function exp may have the `returns_twice' attribute. */
814 /* Process the pure and const attributes. */
833 {
840 }
843 }
845 {
853 }
854 else
858 {
862 }
865 }
867 /* Detect flags from a CALL_EXPR. */
869 int
871 {
879 else
880 {
884 else
888 }
891 }
893 /* Return true if TYPE should be passed by invisible reference. */
895 bool
898 {
900 {
901 /* If this type contains non-trivial constructors, then it is
902 forbidden for the middle-end to create any new copies. */
906 /* GCC post 3.4 passes *all* variable sized types by reference. */
910 /* If a record type should be passed the same as its first (and only)
911 member, use the type and mode of that member. */
913 {
916 }
917 }
921 }
923 /* Return true if TYPE, which is passed by reference, should be callee
924 copied instead of caller copied. */
926 bool
929 {
933 named_arg);
934 }
937 /* Precompute all register parameters as described by ARGS, storing values
938 into fields within the ARGS array.
940 NUM_ACTUALS indicates the total number elements in the ARGS array.
942 Set REG_PARM_SEEN if we encounter a register parameter. */
944 static void
947 {
954 {
958 {
963 }
965 /* If we are to promote the function arg to a wider mode,
966 do it now. */
974 /* If the value is a non-legitimate constant, force it into a
975 pseudo now. TLS symbols sometimes need a call to resolve. */
980 /* If we're going to have to load the value by parts, pull the
981 parts into pseudos. The part extraction process can involve
982 non-trivial computation. */
984 {
989 }
991 /* If the value is expensive, and we are inside an appropriately
992 short loop, put the value into a pseudo and then put the pseudo
993 into the hard reg.
995 For small register classes, also do this if this call uses
996 register parameters. This is to avoid reload conflicts while
997 loading the parameters registers. */
1006 && ((*reg_parm_seen
1010 }
1011 }
1013 #ifdef REG_PARM_STACK_SPACE
1015 /* The argument list is the property of the called routine and it
1016 may clobber it. If the fixed area has been used for previous
1017 parameters, we must save and restore it. */
1019 static rtx
1020 save_fixed_argument_area (int reg_parm_stack_space, rtx argblock, int *low_to_save, int *high_to_save)
1021 {
1025 /* Compute the boundary of the area that needs to be saved, if any. */
1035 {
1037 machine_mode save_mode;
1039 rtx addr;
1040 rtx stack_area;
1041 rtx save_area;
1044 ;
1051 /* If we don't have the required alignment, must do this
1052 in BLKmode. */
1053 scalar_int_mode imode;
1058 else
1063 else
1071 {
1075 }
1076 else
1077 {
1080 }
1083 }
1086 }
1088 static void
1090 {
1097 else
1106 else
1109 BLOCK_OP_CALL_PARM);
1110 }
1113 /* If any elements in ARGS refer to parameters that are to be passed in
1114 registers, but not in memory, and whose alignment does not permit a
1115 direct copy into registers. Copy the values into a group of pseudos
1116 which we will later copy into the appropriate hard registers.
1118 Pseudos for each unaligned argument will be stored into the array
1119 args[argnum].aligned_regs. The caller is responsible for deallocating
1120 the aligned_regs array if it is nonzero. */
1122 static void
1124 {
1134 {
1139 {
1142 }
1143 else
1144 {
1147 }
1151 /* Structures smaller than a word are normally aligned to the
1152 least significant byte. On a BYTES_BIG_ENDIAN machine,
1153 this means we must skip the empty high order bytes when
1154 calculating the bit offset. */
1156 #ifdef BLOCK_REG_PADDING
1160 #else
1161 && BYTES_BIG_ENDIAN
1162 #endif
1163 )
1167 {
1176 /* There is no need to restrict this code to loading items
1177 in TYPE_ALIGN sized hunks. The bitfield instructions can
1178 load up entire word sized registers efficiently.
1180 ??? This may not be needed anymore.
1181 We use to emit a clobber here but that doesn't let later
1182 passes optimize the instructions we emit. By storing 0 into
1183 the register later passes know the first AND to zero out the
1184 bitfield being set in the register is unnecessary. The store
1185 of 0 will be deleted as will at least the first AND. */
1192 }
1193 }
1194 }
1196 /* The limit set by -Walloc-larger-than=. */
1199 /* Initialize ALLOC_OBJECT_SIZE_LIMIT based on the -Walloc-size-larger-than=
1200 setting if the option is specified, or to the maximum object size if it
1201 is not. Return the initialized value. */
1203 static tree
1205 {
1207 {
1211 {
1215 unsigned HOST_WIDE_INT limit
1219 {
1221 {
1222 /* Numeric option arguments are at most INT_MAX. Make it
1223 possible to specify a larger value by accepting common
1224 suffixes. */
1251 else
1253 }
1256 {
1261 }
1262 }
1263 }
1264 }
1266 }
1268 /* Return true when EXP's range can be determined and set RANGE[] to it
1269 after adjusting it if necessary to make EXP a valid size argument to
1270 an allocation function declared with attribute alloc_size (whose
1271 argument may be signed), or to a string manipulation function like
1272 memset. */
1274 bool
1276 {
1278 {
1279 /* EXP is a constant. */
1282 }
1285 enum value_range_type range_type
1290 {
1291 /* No range information available. */
1295 }
1305 {
1307 {
1309 {
1310 /* EXP is not in a strictly negative range. That means
1311 it must be in some (not necessarily strictly) positive
1312 range which includes zero. Since in signed to unsigned
1313 conversions negative values end up converted to large
1314 positive values, and otherwise they are not valid sizes,
1315 the resulting range is in both cases [0, TYPE_MAX]. */
1318 }
1320 {
1321 /* EXP is not in a negative-positive range. That means EXP
1322 is either negative, or greater than max. Since negative
1323 sizes are invalid make the range [MAX + 1, TYPE_MAX]. */
1326 }
1327 else
1328 {
1331 }
1332 }
1334 {
1335 /* EXP is unsigned and not in the range [1, MAX]. That means
1336 it's either zero or greater than MAX. Even though 0 would
1337 normally be detected by -Walloc-zero set the range to
1338 [MAX, TYPE_MAX] so that when MAX is greater than the limit
1339 the whole range is diagnosed. */
1342 }
1343 else
1344 {
1347 }
1348 }
1354 }
1356 /* Diagnose a call EXP to function FN decorated with attribute alloc_size
1357 whose argument numbers given by IDX with values given by ARGS exceed
1358 the maximum object size or cause an unsigned oveflow (wrapping) when
1359 multiplied. When ARGS[0] is null the function does nothing. ARGS[1]
1360 may be null for functions like malloc, and non-null for those like
1361 calloc that are decorated with a two-argument attribute alloc_size. */
1363 void
1365 {
1366 /* The range each of the (up to) two arguments is known to be in. */
1369 /* Maximum object size set by -Walloc-size-larger-than= or SIZE_MAX / 2. */
1376 /* Validate each argument individually. */
1378 {
1380 {
1385 {
1389 }
1391 {
1392 /* Avoid issuing -Walloc-zero for allocation functions other
1393 than __builtin_alloca that are declared with attribute
1394 returns_nonnull because there's no portability risk. This
1395 avoids warning for such calls to libiberty's xmalloc and
1396 friends.
1397 Also avoid issuing the warning for calls to function named
1398 "alloca". */
1407 }
1409 {
1410 /* G++ emits calls to ::operator new[](SIZE_MAX) in C++98
1411 mode and with -fno-exceptions as a way to indicate array
1412 size overflow. There's no good way to detect C++98 here
1413 so avoid diagnosing these calls for all C++ modes. */
1422 "%Kargument %i value %qE exceeds "
1425 }
1426 }
1429 {
1430 /* Verify that the argument's range is not negative (including
1431 upper bound of zero). */
1434 {
1439 }
1441 {
1443 "%Kargument %i range [%E, %E] exceeds "
1447 maxobjsize);
1448 }
1449 }
1450 }
1455 /* For a two-argument alloc_size, validate the product of the two
1456 arguments if both of their values or ranges are known. */
1461 {
1462 /* Check for overflow in the product of a function decorated with
1463 attribute alloc_size (X, Y). */
1473 "%Kproduct %<%E * %E%> of arguments %i and %i "
1479 "%Kproduct %<%E * %E%> of arguments %i and %i "
1483 maxobjsize);
1486 {
1487 /* Print the full range of each of the two arguments to make
1488 it clear when it is, in fact, in a range and not constant. */
1495 }
1496 }
1499 {
1505 else
1508 }
1509 }
1511 /* Issue an error if CALL_EXPR was flagged as requiring
1512 tall-call optimization. */
1514 static void
1516 {
1522 }
1524 /* Fill in ARGS_SIZE and ARGS array based on the parameters found in
1525 CALL_EXPR EXP.
1527 NUM_ACTUALS is the total number of parameters.
1529 N_NAMED_ARGS is the total number of named arguments.
1531 STRUCT_VALUE_ADDR_VALUE is the implicit argument for a struct return
1532 value, or null.
1534 FNDECL is the tree code for the target of this call (if known)
1536 ARGS_SO_FAR holds state needed by the target to know where to place
1537 the next argument.
1539 REG_PARM_STACK_SPACE is the number of bytes of stack space reserved
1540 for arguments which are passed in registers.
1542 OLD_STACK_LEVEL is a pointer to an rtx which olds the old stack level
1543 and may be modified by this routine.
1545 OLD_PENDING_ADJ, MUST_PREALLOCATE and FLAGS are pointers to integer
1546 flags which may be modified by this routine.
1548 MAY_TAILCALL is cleared if we encounter an invisible pass-by-reference
1549 that requires allocation of stack space.
1551 CALL_FROM_THUNK_P is true if this call is the jump from a thunk to
1552 the thunked-to function. */
1554 static void
1561 cumulative_args_t args_so_far,
1566 {
1570 /* Count arg position in order args appear. */
1580 /* In this loop, we consider args in the order they are written.
1581 We fill up ARGS from the back. */
1584 {
1586 call_expr_arg_iterator iter;
1587 tree arg;
1591 {
1593 j--;
1595 /* If we pass structure address then we need to
1596 create bounds for it. Since created bounds is
1597 a call statement, we expand it right here to avoid
1598 fixing all other places where it may be expanded. */
1600 {
1607 j--;
1608 }
1609 }
1612 {
1615 /* Remember last param with pointer and associate it
1616 with following pointer bounds. */
1619 {
1624 {
1627 }
1628 }
1632 {
1636 }
1638 {
1639 /* We expect bounds in instrumented calls only.
1640 Otherwise it is a sign we lost flag due to some optimization
1641 and may emit call args incorrectly. */
1644 /* For structures look for the next available pointer. */
1646 {
1653 /* Check we have no more pointers in the structure. */
1656 }
1659 /* Check we covered all pointers in the previous
1660 non bounds arg. */
1663 }
1664 else
1668 && argtype
1671 {
1674 j--;
1676 }
1677 else
1679 j--;
1680 argpos++;
1681 }
1685 }
1689 /* Extract attribute alloc_size and if set, store the indices of
1690 the corresponding arguments in ALLOC_IDX, and then the actual
1691 argument(s) at those indices in ALLOC_ARGS. */
1697 {
1702 }
1704 /* Array for up to the two attribute alloc_size arguments. */
1707 /* I counts args in order (to be) pushed; ARGPOS counts in order written. */
1709 {
1712 machine_mode mode;
1714 /* Replace erroneous argument with constant zero. */
1718 /* If TYPE is a transparent union or record, pass things the way
1719 we would pass the first field of the union or record. We have
1720 already verified that the modes are the same. */
1725 /* Decide where to pass this arg.
1727 args[i].reg is nonzero if all or part is passed in registers.
1729 args[i].partial is nonzero if part but not all is passed in registers,
1730 and the exact value says how many bytes are passed in registers.
1732 args[i].pass_on_stack is nonzero if the argument must at least be
1733 computed on the stack. It may then be loaded back into registers
1734 if args[i].reg is nonzero.
1736 These decisions are driven by the FUNCTION_... macros and must agree
1737 with those made by function.c. */
1739 /* See if this argument should be passed by invisible reference. */
1742 {
1746 callee_copies
1750 /* If we're compiling a thunk, pass through invisible references
1751 instead of making a copy. */
1753 || (callee_copies
1758 {
1759 /* We may have turned the parameter value into an SSA name.
1760 Go back to the original parameter so we can take the
1761 address. */
1763 {
1767 }
1768 /* Argument setup code may have copied the value to register. We
1769 revert that optimization now because the tail call code must
1770 use the original location. */
1780 /* We can't use sibcalls if a callee-copied argument is
1781 stored in the current function's frame. */
1783 {
1786 "a callee-copied argument is"
1787 " stored in the current "
1789 }
1797 }
1798 else
1799 {
1800 /* We make a copy of the object and pass the address to the
1801 function being called. */
1802 rtx copy;
1809 {
1810 /* This is a variable-sized object. Make space on the stack
1811 for it. */
1815 {
1819 }
1821 /* We can pass TRUE as the 4th argument because we just
1822 saved the stack pointer and will restore it right after
1823 the call. */
1830 }
1831 else
1836 /* Just change the const function to pure and then let
1837 the next test clear the pure based on
1838 callee_copies. */
1840 {
1843 }
1853 "argument must be passed"
1855 }
1856 }
1869 {
1872 }
1874 /* If this is a sibling call and the machine has register windows, the
1875 register window has to be unwinded before calling the routine, so
1876 arguments have to go into the incoming registers. */
1881 else
1891 /* If FUNCTION_ARG returned a (parallel [(expr_list (nil) ...) ...]),
1892 it means that we are to pass this arg in the register(s) designated
1893 by the PARALLEL, but also to pass it in the stack. */
1898 /* If this is an addressable type, we must preallocate the stack
1899 since we must evaluate the object into its final location.
1901 If this is to be passed in both registers and the stack, it is simpler
1902 to preallocate. */
1907 /* No stack allocation and padding for bounds. */
1909 ;
1910 /* Compute the stack-size of this argument. */
1915 #ifdef STACK_PARMS_IN_REG_PARM_AREA
1917 #else
1919 #endif
1920 reg_parm_stack_space,
1923 #ifdef BLOCK_REG_PADDING
1924 else
1925 /* The argument is passed entirely in registers. See at which
1926 end it should be padded. */
1930 #endif
1932 /* Update ARGS_SIZE, the total stack space for args so far. */
1938 /* Increment ARGS_SO_FAR, which has info about which arg-registers
1939 have been used, etc. */
1944 /* Store argument values for functions decorated with attribute
1945 alloc_size. */
1950 }
1953 {
1954 /* Check the arguments of functions decorated with attribute
1955 alloc_size. */
1957 }
1958 }
1960 /* Update ARGS_SIZE to contain the total size for the argument block.
1961 Return the original constant component of the argument block's size.
1963 REG_PARM_STACK_SPACE holds the number of bytes of stack space reserved
1964 for arguments passed in registers. */
1966 static int
1969 tree fndecl ATTRIBUTE_UNUSED,
1970 tree fntype ATTRIBUTE_UNUSED,
1972 {
1975 /* For accumulate outgoing args mode we don't need to align, since the frame
1976 will be already aligned. Align to STACK_BOUNDARY in order to prevent
1977 backends from generating misaligned frame sizes. */
1981 /* Compute the actual size of the argument block required. The variable
1982 and constant sizes must be combined, the size may have to be rounded,
1983 and there may be a minimum required size. */
1986 {
1992 {
1993 /* We don't handle this case yet. To handle it correctly we have
1994 to add the delta, round and subtract the delta.
1995 Currently no machine description requires this support. */
1998 }
2001 {
2002 args_size->var
2006 /* The area corresponding to register parameters is not to count in
2007 the size of the block we need. So make the adjustment. */
2009 args_size->var
2012 }
2013 }
2014 else
2015 {
2020 + stack_pointer_delta
2022 / preferred_stack_boundary
2027 reg_parm_stack_space);
2031 }
2033 }
2035 /* Precompute parameters as needed for a function call.
2037 FLAGS is mask of ECF_* constants.
2039 NUM_ACTUALS is the number of arguments.
2041 ARGS is an array containing information for each argument; this
2042 routine fills in the INITIAL_VALUE and VALUE fields for each
2043 precomputed argument. */
2045 static void
2047 {
2050 /* If this is a libcall, then precompute all arguments so that we do not
2051 get extraneous instructions emitted as part of the libcall sequence. */
2053 /* If we preallocated the stack space, and some arguments must be passed
2054 on the stack, then we must precompute any parameter which contains a
2055 function call which will store arguments on the stack.
2056 Otherwise, evaluating the parameter may clobber previous parameters
2057 which have already been stored into the stack. (we have code to avoid
2058 such case by saving the outgoing stack arguments, but it results in
2059 worse code) */
2064 {
2065 tree type;
2066 machine_mode mode;
2071 /* If this is an addressable type, we cannot pre-evaluate it. */
2080 {
2086 /* CSE will replace this only if it contains args[i].value
2087 pseudo, so convert it down to the declared mode using
2088 a SUBREG. */
2092 {
2097 }
2098 }
2099 }
2100 }
2102 /* Given the current state of MUST_PREALLOCATE and information about
2103 arguments to a function call in NUM_ACTUALS, ARGS and ARGS_SIZE,
2104 compute and return the final value for MUST_PREALLOCATE. */
2106 static int
2109 {
2110 /* See if we have or want to preallocate stack space.
2112 If we would have to push a partially-in-regs parm
2113 before other stack parms, preallocate stack space instead.
2115 If the size of some parm is not a multiple of the required stack
2116 alignment, we must preallocate.
2118 If the total size of arguments that would otherwise create a copy in
2119 a temporary (such as a CALL) is more than half the total argument list
2120 size, preallocation is faster.
2122 Another reason to preallocate is if we have a machine (like the m88k)
2123 where stack alignment is required to be maintained between every
2124 pair of insns, not just when the call is made. However, we assume here
2125 that such machines either do not have push insns (and hence preallocation
2126 would occur anyway) or the problem is taken care of with
2127 PUSH_ROUNDING. */
2130 {
2136 {
2141 /* We preallocate in case there are bounds passed
2142 in the bounds table to have precomputed address
2143 for bounds association. */
2153 copy_to_evaluate_size
2155 }
2160 }
2162 }
2164 /* If we preallocated stack space, compute the address of each argument
2165 and store it into the ARGS array.
2167 We need not ensure it is a valid memory address here; it will be
2168 validized when it is used.
2170 ARGBLOCK is an rtx for the address of the outgoing arguments. */
2172 static void
2174 {
2176 {
2184 {
2187 rtx addr;
2192 /* Skip this parm if it will not be passed on the stack. */
2198 /* Pointer Bounds are never passed on the stack. */
2204 else
2210 {
2211 /* Only part of the parameter is being passed on the stack.
2212 Generate a simple memory reference of the correct size. */
2218 }
2219 else
2220 {
2224 }
2230 {
2233 }
2238 else
2244 {
2245 /* Only part of the parameter is being passed on the stack.
2246 Generate a simple memory reference of the correct size.
2247 */
2250 }
2251 else
2252 {
2256 }
2259 /* Function incoming arguments may overlap with sibling call
2260 outgoing arguments and we cannot allow reordering of reads
2261 from function arguments with stores to outgoing arguments
2262 of sibling calls. */
2265 }
2266 }
2267 }
2269 /* Given a FNDECL and EXP, return an rtx suitable for use as a target address
2270 in a call instruction.
2272 FNDECL is the tree node for the target function. For an indirect call
2273 FNDECL will be NULL_TREE.
2275 ADDR is the operand 0 of CALL_EXPR for this call. */
2277 static rtx
2279 {
2280 rtx funexp;
2282 /* Get the function to call, in the form of RTL. */
2284 {
2288 /* Get a SYMBOL_REF rtx for the function address. */
2290 }
2291 else
2292 /* Generate an rtx (probably a pseudo-register) for the address. */
2293 {
2297 }
2299 }
2301 /* Internal state for internal_arg_pointer_based_exp and its helpers. */
2302 static struct
2303 {
2304 /* Last insn that has been scanned by internal_arg_pointer_based_exp_scan,
2305 or NULL_RTX if none has been scanned yet. */
2307 /* Vector indexed by REGNO - FIRST_PSEUDO_REGISTER, recording if a pseudo is
2308 based on crtl->args.internal_arg_pointer. The element is NULL_RTX if the
2309 pseudo isn't based on it, a CONST_INT offset if the pseudo is based on it
2310 with fixed offset, or PC if this is with variable or unknown offset. */
2316 /* Helper function for internal_arg_pointer_based_exp. Scan insns in
2317 the tail call sequence, starting with first insn that hasn't been
2318 scanned yet, and note for each pseudo on the LHS whether it is based
2319 on crtl->args.internal_arg_pointer or not, and what offset from that
2320 that pointer it has. */
2322 static void
2324 {
2329 else
2333 {
2336 {
2339 /* Punt on pseudos set multiple times. */
2344 else
2347 {
2349 internal_arg_pointer_exp_state.cache
2352 }
2353 }
2357 }
2360 }
2362 /* Compute whether RTL is based on crtl->args.internal_arg_pointer. Return
2363 NULL_RTX if RTL isn't based on it, a CONST_INT offset if RTL is based on
2364 it with fixed offset, or PC if this is with variable or unknown offset.
2365 TOPLEVEL is true if the function is invoked at the topmost level. */
2367 static rtx
2369 {
2380 {
2385 }
2387 /* When called at the topmost level, scan pseudo assignments in between the
2388 last scanned instruction in the tail call sequence and the latest insn
2389 in that sequence. */
2394 {
2400 }
2404 {
2410 }
2413 }
2415 /* Return true if and only if SIZE storage units (usually bytes)
2416 starting from address ADDR overlap with already clobbered argument
2417 area. This function is used to determine if we should give up a
2418 sibcall. */
2420 static bool
2422 {
2423 HOST_WIDE_INT i;
2424 rtx val;
2433 else
2438 else
2446 {
2453 }
2456 }
2458 /* Do the register loads required for any wholly-register parms or any
2459 parms which are passed both on the stack and in a register. Their
2460 expressions were already evaluated.
2462 Mark all register-parms as living through the call, putting these USE
2463 insns in the CALL_INSN_FUNCTION_USAGE field.
2465 When IS_SIBCALL, perform the check_sibcall_argument_overlap
2466 checking, setting *SIBCALL_FAILURE if appropriate. */
2468 static void
2472 {
2476 {
2480 {
2485 /* Set non-negative if we must move a word at a time, even if
2486 just one word (e.g, partial == 4 && mode == DFmode). Set
2487 to -1 if we just use a normal move insn. This value can be
2488 zero if the argument is a zero size structure. */
2491 ;
2493 {
2496 }
2498 {
2501 }
2502 else
2505 /* Handle calls that pass values in multiple non-contiguous
2506 locations. The Irix 6 ABI has examples of this. */
2511 /* If simple case, just do move. If normal partial, store_one_arg
2512 has already loaded the register for us. In all other cases,
2513 load the register(s) from memory. */
2516 {
2518 #ifdef BLOCK_REG_PADDING
2519 /* Handle case where we have a value that needs shifting
2520 up to the msb. eg. a QImode value and we're padding
2521 upward on a BYTES_BIG_ENDIAN machine. */
2525 {
2526 rtx x;
2529 /* Assigning REG here rather than a temp makes CALL_FUSAGE
2530 report the whole reg as used. Strictly speaking, the
2531 call only uses SIZE bytes at the msb end, but it doesn't
2532 seem worth generating rtl to say that. */
2537 }
2538 #endif
2539 }
2541 /* If we have pre-computed the values to put in the registers in
2542 the case of non-aligned structures, copy them in now. */
2550 {
2553 /* Check for overlap with already clobbered argument area,
2554 providing that this has non-zero size. */
2557 && (mem_overlaps_already_clobbered_arg_p
2564 else
2565 {
2574 NULL);
2580 }
2582 /* Handle a BLKmode that needs shifting. */
2584 #ifdef BLOCK_REG_PADDING
2586 #else
2587 && BYTES_BIG_ENDIAN
2588 #endif
2589 )
2590 {
2595 rtx x;
2600 }
2601 }
2603 /* When a parameter is a block, and perhaps in other cases, it is
2604 possible that it did a load from an argument slot that was
2605 already clobbered. */
2610 /* Handle calls that pass values in multiple non-contiguous
2611 locations. The Irix 6 ABI has examples of this. */
2619 }
2620 }
2621 }
2623 /* We need to pop PENDING_STACK_ADJUST bytes. But, if the arguments
2624 wouldn't fill up an even multiple of PREFERRED_UNIT_STACK_BOUNDARY
2625 bytes, then we would need to push some additional bytes to pad the
2626 arguments. So, we compute an adjust to the stack pointer for an
2627 amount that will leave the stack under-aligned by UNADJUSTED_ARGS_SIZE
2628 bytes. Then, when the arguments are pushed the stack will be perfectly
2629 aligned. ARGS_SIZE->CONSTANT is set to the number of bytes that should
2630 be popped after the call. Returns the adjustment. */
2632 static int
2636 {
2637 /* The number of bytes to pop so that the stack will be
2638 under-aligned by UNADJUSTED_ARGS_SIZE bytes. */
2639 HOST_WIDE_INT adjustment;
2640 /* The alignment of the stack after the arguments are pushed, if we
2641 just pushed the arguments without adjust the stack here. */
2644 unadjusted_alignment
2648 /* We want to get rid of as many of the PENDING_STACK_ADJUST bytes
2649 as possible -- leaving just enough left to cancel out the
2650 UNADJUSTED_ALIGNMENT. In other words, we want to ensure that the
2651 PENDING_STACK_ADJUST is non-negative, and congruent to
2652 -UNADJUSTED_ALIGNMENT modulo the PREFERRED_UNIT_STACK_BOUNDARY. */
2654 /* Begin by trying to pop all the bytes. */
2655 unadjusted_alignment
2656 = (unadjusted_alignment
2659 /* Push enough additional bytes that the stack will be aligned
2660 after the arguments are pushed. */
2664 /* Now, sets ARGS_SIZE->CONSTANT so that we pop the right number of
2665 bytes after the call. The right number is the entire
2666 PENDING_STACK_ADJUST less our ADJUSTMENT plus the amount required
2667 by the arguments in the first place. */
2668 args_size->constant
2672 }
2674 /* Scan X expression if it does not dereference any argument slots
2675 we already clobbered by tail call arguments (as noted in stored_args_map
2676 bitmap).
2677 Return nonzero if X expression dereferences such argument slots,
2678 zero otherwise. */
2680 static int
2682 {
2683 RTX_CODE code;
2692 /* We need not check the operands of the CALL expression itself. */
2700 /* Scan all subexpressions. */
2703 {
2705 {
2708 }
2710 {
2714 }
2715 }
2717 }
2719 /* Scan sequence after INSN if it does not dereference any argument slots
2720 we already clobbered by tail call arguments (as noted in stored_args_map
2721 bitmap). If MARK_STORED_ARGS_MAP, add stack slots for ARG to
2722 stored_args_map bitmap afterwards (when ARG is a register MARK_STORED_ARGS_MAP
2723 should be 0). Return nonzero if sequence after INSN dereferences such argument
2724 slots, zero otherwise. */
2726 static int
2729 {
2734 else
2743 {
2746 else
2751 }
2753 }
2755 /* Given that a function returns a value of mode MODE at the most
2756 significant end of hard register VALUE, shift VALUE left or right
2757 as specified by LEFT_P. Return true if some action was needed. */
2759 bool
2761 {
2762 HOST_WIDE_INT shift;
2769 /* Use ashr rather than lshr for right shifts. This is for the benefit
2770 of the MIPS port, which requires SImode values to be sign-extended
2771 when stored in 64-bit registers. */
2776 }
2778 /* If X is a likely-spilled register value, copy it to a pseudo
2779 register and return that register. Return X otherwise. */
2781 static rtx
2783 {
2784 rtx new_rtx;
2789 {
2790 /* Make sure that we generate a REG rather than a CONCAT.
2791 Moves into CONCATs can need nontrivial instructions,
2792 and the whole point of this function is to avoid
2793 using the hard register directly in such a situation. */
2799 }
2801 }
2803 /* Helper function for expand_call.
2804 Return false is EXP is not implementable as a sibling call. */
2806 static bool
2808 rtx structure_value_addr,
2809 tree funtype,
2811 tree fndecl,
2813 tree addr,
2815 {
2817 {
2818 maybe_complain_about_tail_call
2820 "machine description does not have"
2823 }
2825 /* Doing sibling call optimization needs some work, since
2826 structure_value_addr can be allocated on the stack.
2827 It does not seem worth the effort since few optimizable
2828 sibling calls will return a structure. */
2830 {
2833 }
2835 #ifdef REG_PARM_STACK_SPACE
2836 /* If outgoing reg parm stack space changes, we can not do sibcall. */
2840 {
2842 "inconsistent size of stack space"
2843 " allocated for arguments which are"
2846 }
2847 #endif
2849 /* Check whether the target is able to optimize the call
2850 into a sibcall. */
2852 {
2854 "target is not able to optimize the"
2857 }
2859 /* Functions that do not return exactly once may not be sibcall
2860 optimized. */
2862 {
2865 }
2867 {
2870 }
2873 {
2876 }
2878 /* If the called function is nested in the current one, it might access
2879 some of the caller's arguments, but could clobber them beforehand if
2880 the argument areas are shared. */
2882 {
2885 }
2887 /* If this function requires more stack slots than the current
2888 function, we cannot change it into a sibling call.
2889 crtl->args.pretend_args_size is not part of the
2890 stack allocated by our caller. */
2892 {
2894 "callee required more stack slots"
2897 }
2899 /* If the callee pops its own arguments, then it must pop exactly
2900 the same number of arguments as the current function. */
2905 {
2907 "inconsistent number of"
2910 }
2913 {
2917 }
2919 /* All checks passed. */
2921 }
2923 /* Generate all the code for a CALL_EXPR exp
2924 and return an rtx for its value.
2925 Store the value in TARGET (specified as an rtx) if convenient.
2926 If the value is stored in TARGET then TARGET is returned.
2927 If IGNORE is nonzero, then we ignore the value of the function call. */
2929 rtx
2931 {
2932 /* Nonzero if we are currently expanding a call. */
2935 /* RTX for the function to be called. */
2936 rtx funexp;
2937 /* Sequence of insns to perform a normal "call". */
2939 /* Sequence of insns to perform a tail "call". */
2941 /* Data type of the function. */
2942 tree funtype;
2943 tree type_arg_types;
2944 tree rettype;
2945 /* Declaration of the function being called,
2946 or 0 if the function is computed (not known by name). */
2948 /* The type of the function being called. */
2949 tree fntype;
2954 /* Register in which non-BLKmode value will be returned,
2955 or 0 if no value or if value is BLKmode. */
2956 rtx valreg;
2957 /* Register(s) in which bounds are returned. */
2959 /* Address where we should return a BLKmode value;
2960 0 if value not BLKmode. */
2962 /* Nonzero if that address is being passed by treating it as
2963 an extra, implicit first parameter. Otherwise,
2964 it is passed by being copied directly into struct_value_rtx. */
2966 /* Holds the value of implicit argument for the struct value. */
2968 /* Size of aggregate value wanted, or zero if none wanted
2969 or if we are using the non-reentrant PCC calling convention
2970 or expecting the value in registers. */
2972 /* Nonzero if called function returns an aggregate in memory PCC style,
2973 by returning the address of where to find it. */
2977 /* Number of actual parameters in this call, including struct value addr. */
2979 /* Number of named args. Args after this are anonymous ones
2980 and they must all go on the stack. */
2982 /* Number of complex actual arguments that need to be split. */
2985 /* Vector of information about each argument.
2986 Arguments are numbered in the order they will be pushed,
2987 not the order they are written. */
2990 /* Total size in bytes of all the stack-parms scanned so far. */
2993 /* Size of arguments before any adjustments (such as rounding). */
2995 /* Data on reg parms scanned so far. */
2996 CUMULATIVE_ARGS args_so_far_v;
2997 cumulative_args_t args_so_far;
2998 /* Nonzero if a reg parm has been scanned. */
3000 /* Nonzero if this is an indirect function call. */
3002 /* Nonzero if we must avoid push-insns in the args for this call.
3003 If stack space is allocated for register parameters, but not by the
3004 caller, then it is preallocated in the fixed part of the stack frame.
3005 So the entire argument block must then be preallocated (i.e., we
3006 ignore PUSH_ROUNDING in that case). */
3010 /* Size of the stack reserved for parameter registers. */
3013 /* Address of space preallocated for stack parms
3014 (on machines that lack push insns), or 0 if space not preallocated. */
3017 /* Mask of ECF_ and ERF_ flags. */
3020 #ifdef REG_PARM_STACK_SPACE
3021 /* Define the boundary of the register parm stack space that needs to be
3022 saved, if any. */
3025 #endif
3033 /* State variables to track stack modifications. */
3039 /* Some stack pointer alterations we make are performed via
3040 allocate_dynamic_stack_space. This modifies the stack_pointer_delta,
3041 which we then also need to save/restore along the way. */
3044 rtx call_fusage;
3047 /* The alignment of the stack, in bits. */
3049 /* The alignment of the stack, in bytes. */
3051 /* The static chain value to use for this call. */
3052 rtx static_chain_value;
3053 /* See if this is "nothrow" function call. */
3057 /* See if we can find a DECL-node for the actual function, and get the
3058 function attributes (flags) from the function decl or type node. */
3061 {
3065 }
3066 else
3067 {
3072 }
3077 /* Warn if this value is an aggregate type,
3078 regardless of which calling convention we are using for it. */
3082 /* If the result of a non looping pure or const function call is
3083 ignored (or void), and none of its arguments are volatile, we can
3084 avoid expanding the call and just evaluate the arguments for
3085 side-effects. */
3090 {
3092 tree arg;
3093 call_expr_arg_iterator iter;
3097 {
3100 }
3103 {
3107 }
3108 }
3110 #ifdef REG_PARM_STACK_SPACE
3112 #endif
3118 /* Set up a place to return a structure. */
3120 /* Cater to broken compilers. */
3122 {
3123 /* This call returns a big structure. */
3126 #ifdef PCC_STATIC_STRUCT_RETURN
3127 {
3129 }
3131 {
3134 /* Even if it is semantically safe to use the target as the return
3135 slot, it may be not sufficiently aligned for the return type. */
3137 && target
3143 else
3144 {
3145 /* For variable-sized objects, we must be called with a target
3146 specified. If we were to allocate space on the stack here,
3147 we would have no way of knowing when to free it. */
3151 }
3152 }
3154 }
3156 /* Figure out the amount to which the stack should be aligned. */
3159 {
3161 /* Without automatic stack alignment, we can't increase preferred
3162 stack boundary. With automatic stack alignment, it is
3163 unnecessary since unless we can guarantee that all callers will
3164 align the outgoing stack properly, callee has to align its
3165 stack anyway. */
3170 }
3172 /* Operand 0 is a pointer-to-function; get the type of the function. */
3177 /* Count whether there are actual complex arguments that need to be split
3178 into their real and imaginary parts. Munge the type_arg_types
3179 appropriately here as well. */
3181 {
3182 call_expr_arg_iterator iter;
3183 tree arg;
3185 {
3189 num_complex_actuals++;
3190 }
3192 }
3193 else
3199 /* If struct_value_rtx is 0, it means pass the address
3200 as if it were an extra parameter. Put the argument expression
3201 in structure_value_addr_value. */
3203 {
3204 /* If structure_value_addr is a REG other than
3205 virtual_outgoing_args_rtx, we can use always use it. If it
3206 is not a REG, we must always copy it into a register.
3207 If it is virtual_outgoing_args_rtx, we must copy it to another
3208 register in some cases. */
3210 || (ACCUMULATE_OUTGOING_ARGS
3211 && stack_arg_under_construction
3217 structure_value_addr_value =
3220 }
3222 /* Count the arguments and set NUM_ACTUALS. */
3223 num_actuals =
3226 /* Compute number of named args.
3227 First, do a raw count of the args for INIT_CUMULATIVE_ARGS. */
3230 n_named_args
3232 /* Count the struct value address, if it is passed as a parm. */
3234 else
3235 /* If we know nothing, treat all args as named. */
3238 /* Start updating where the next arg would go.
3240 On some machines (such as the PA) indirect calls have a different
3241 calling convention than normal calls. The fourth argument in
3242 INIT_CUMULATIVE_ARGS tells the backend if this is an indirect call
3243 or not. */
3247 /* Now possibly adjust the number of named args.
3248 Normally, don't include the last named arg if anonymous args follow.
3249 We do include the last named arg if
3250 targetm.calls.strict_argument_naming() returns nonzero.
3251 (If no anonymous args follow, the result of list_length is actually
3252 one too large. This is harmless.)
3254 If targetm.calls.pretend_outgoing_varargs_named() returns
3255 nonzero, and targetm.calls.strict_argument_naming() returns zero,
3256 this machine will be able to place unnamed args that were passed
3257 in registers into the stack. So treat all args as named. This
3258 allows the insns emitting for a specific argument list to be
3259 independent of the function declaration.
3261 If targetm.calls.pretend_outgoing_varargs_named() returns zero,
3262 we do not have any reliable way to pass unnamed args in
3263 registers, so we must force them into memory. */
3267 ;
3270 /* Don't include the last named arg. */
3272 else
3273 /* Treat all args as named. */
3276 /* Make a vector to hold all the information about each arg. */
3279 /* Build up entries in the ARGS array, compute the size of the
3280 arguments into ARGS_SIZE, etc. */
3292 /* Now make final decision about preallocating stack space. */
3297 /* If the structure value address will reference the stack pointer, we
3298 must stabilize it. We don't need to do this if we know that we are
3299 not going to adjust the stack pointer in processing this call. */
3304 structure_value_addr))
3309 /* Tail calls can make things harder to debug, and we've traditionally
3310 pushed these optimizations into -O2. Don't try if we're already
3311 expanding a call, as that means we're an argument. Don't try if
3312 there's cleanups, as we know there's code to follow the call. */
3315 || !flag_optimize_sibling_calls
3320 /* If the user has marked the function as requiring tail-call
3321 optimization, attempt it. */
3325 /* Rest of purposes for tail call optimizations to fail. */
3328 structure_value_addr,
3329 funtype,
3330 reg_parm_stack_space,
3331 fndecl,
3334 /* Check if caller and callee disagree in promotion of function
3335 return value. */
3337 {
3347 caller_promoted_mode
3351 callee_promoted_mode
3362 {
3365 "caller and callee disagree in"
3366 " promotion of function"
3368 }
3369 }
3371 /* Ensure current function's preferred stack boundary is at least
3372 what we need. Stack alignment may also increase preferred stack
3373 boundary. */
3376 else
3381 /* We want to make two insn chains; one for a sibling call, the other
3382 for a normal call. We will select one of the two chains after
3383 initial RTL generation is complete. */
3385 {
3387 /* We want to emit any pending stack adjustments before the tail
3388 recursion "call". That way we know any adjustment after the tail
3389 recursion call can be ignored if we indeed use the tail
3390 call expansion. */
3391 saved_pending_stack_adjust save;
3393 rtx next_arg_reg;
3396 {
3397 /* State variables we need to save and restore between
3398 iterations. */
3400 }
3403 else
3406 /* Other state variables that we must reinitialize each time
3407 through the loop (that are not initialized by the loop itself). */
3411 /* Start a new sequence for the normal call case.
3413 From this point on, if the sibling call fails, we want to set
3414 sibcall_failure instead of continuing the loop. */
3417 /* Don't let pending stack adjusts add up to too much.
3418 Also, do all pending adjustments now if there is any chance
3419 this might be a call to alloca or if we are expanding a sibling
3420 call sequence.
3421 Also do the adjustments before a throwing call, otherwise
3422 exception handling can fail; PR 19225. */
3431 /* Precompute any arguments as needed. */
3435 /* Now we are about to start emitting insns that can be deleted
3436 if a libcall is deleted. */
3446 /* Compute the actual size of the argument block required. The variable
3447 and constant sizes must be combined, the size may have to be rounded,
3448 and there may be a minimum required size. When generating a sibcall
3449 pattern, do not round up, since we'll be re-using whatever space our
3450 caller provided. */
3451 unadjusted_args_size
3460 /* The argument block when performing a sibling call is the
3461 incoming argument block. */
3463 {
3466 argblock
3468 else
3469 argblock
3474 }
3476 /* If we have no actual push instructions, or shouldn't use them,
3477 make space for all args right now. */
3479 {
3481 {
3486 /* stack_arg_under_construction says whether a stack arg is
3487 being constructed at the old stack level. Pushing the stack
3488 gets a clean outgoing argument block. */
3491 }
3495 }
3496 else
3497 {
3498 /* Note that we must go through the motions of allocating an argument
3499 block even if the size is zero because we may be storing args
3500 in the area reserved for register arguments, which may be part of
3501 the stack frame. */
3505 /* Store the maximum argument space used. It will be pushed by
3506 the prologue (if ACCUMULATE_OUTGOING_ARGS, or stack overflow
3507 checking). */
3513 {
3515 {
3516 /* Since the stack pointer will never be pushed, it is
3517 possible for the evaluation of a parm to clobber
3518 something we have already written to the stack.
3519 Since most function calls on RISC machines do not use
3520 the stack, this is uncommon, but must work correctly.
3522 Therefore, we save any area of the stack that was already
3523 written and that we are using. Here we set up to do this
3524 by making a new stack usage map from the old one. The
3525 actual save will be done by store_one_arg.
3527 Another approach might be to try to reorder the argument
3528 evaluations to avoid this conflicting stack usage. */
3530 /* Since we will be writing into the entire argument area,
3531 the map must be allocated for its entire size, not just
3532 the part that is the responsibility of the caller. */
3537 highest_outgoing_arg_in_use
3539 else
3540 highest_outgoing_arg_in_use
3549 initial_highest_arg_in_use);
3553 (highest_outgoing_arg_in_use
3557 /* The address of the outgoing argument list must not be
3558 copied to a register here, because argblock would be left
3559 pointing to the wrong place after the call to
3560 allocate_dynamic_stack_space below. */
3563 }
3564 else
3565 {
3567 {
3568 /* Try to reuse some or all of the pending_stack_adjust
3569 to get this space. */
3570 needed
3571 = (combine_pending_stack_adjustment_and_call
3574 preferred_unit_stack_boundary));
3576 /* combine_pending_stack_adjustment_and_call computes
3577 an adjustment before the arguments are allocated.
3578 Account for them and see whether or not the stack
3579 needs to go up or down. */
3583 {
3584 /* We're releasing stack space. */
3585 /* ??? We can avoid any adjustment at all if we're
3586 already aligned. FIXME. */
3590 }
3591 else
3592 /* We need to allocate space. We'll do that in
3593 push_block below. */
3595 }
3597 /* Special case this because overhead of `push_block' in
3598 this case is non-trivial. */
3601 else
3602 {
3606 }
3608 /* We only really need to call `copy_to_reg' in the case
3609 where push insns are going to be used to pass ARGBLOCK
3610 to a function call in ARGS. In that case, the stack
3611 pointer changes value from the allocation point to the
3612 call point, and hence the value of
3613 VIRTUAL_OUTGOING_ARGS_RTX changes as well. But might
3614 as well always do it. */
3616 }
3617 }
3618 }
3621 {
3622 /* The save/restore code in store_one_arg handles all
3623 cases except one: a constructor call (including a C
3624 function returning a BLKmode struct) to initialize
3625 an argument. */
3627 {
3628 rtx push_size
3634 {
3639 /* stack_arg_under_construction says whether a stack
3640 arg is being constructed at the old stack level.
3641 Pushing the stack gets a clean outgoing argument
3642 block. */
3643 old_stack_arg_under_construction
3646 /* Make a new map for the new argument list. */
3651 }
3652 /* We can pass TRUE as the 4th argument because we just
3653 saved the stack pointer and will restore it right after
3654 the call. */
3657 }
3659 /* If argument evaluation might modify the stack pointer,
3660 copy the address of the argument list to a register. */
3663 {
3666 }
3667 }
3671 /* Stack is properly aligned, pops can't safely be deferred during
3672 the evaluation of the arguments. */
3673 NO_DEFER_POP;
3675 /* Precompute all register parameters. It isn't safe to compute
3676 anything once we have started filling any specific hard regs.
3677 TLS symbols sometimes need a call to resolve. Precompute
3678 register parameters before any stack pointer manipulation
3679 to avoid unaligned stack in the called function. */
3682 OK_DEFER_POP;
3684 /* Perform stack alignment before the first push (the last arg). */
3688 {
3689 /* When the stack adjustment is pending, we get better code
3690 by combining the adjustments. */
3693 {
3694 pending_stack_adjust
3695 = (combine_pending_stack_adjustment_and_call
3698 preferred_unit_stack_boundary));
3700 }
3704 }
3705 /* Now that the stack is properly aligned, pops can't safely
3706 be deferred during the evaluation of the arguments. */
3707 NO_DEFER_POP;
3709 /* Record the maximum pushed stack space size. We need to delay
3710 doing it this far to take into account the optimization done
3711 by combine_pending_stack_adjustment_and_call. */
3713 && !ACCUMULATE_OUTGOING_ARGS
3714 && pass
3716 {
3720 }
3726 else
3729 #ifdef REG_PARM_STACK_SPACE
3730 /* Save the fixed argument area if it's part of the caller's frame and
3731 is clobbered by argument setup for this call. */
3735 #endif
3737 /* Now store (and compute if necessary) all non-register parms.
3738 These come before register parms, since they can require block-moves,
3739 which could clobber the registers used for register parms.
3740 Parms which have partial registers are not stored here,
3741 but we do preallocate space here if they want that. */
3744 {
3745 /* Delay bounds until all other args are stored. */
3749 {
3752 /* We don't allow passing huge (> 2^30 B) arguments
3753 by value. It would cause an overflow later on. */
3756 {
3759 }
3763 reg_parm_stack_space)
3768 }
3771 call_fusage
3774 call_fusage);
3775 }
3777 /* If we have a parm that is passed in registers but not in memory
3778 and whose alignment does not permit a direct copy into registers,
3779 make a group of pseudos that correspond to each register that we
3780 will later fill. */
3784 /* Now store any partially-in-registers parm.
3785 This is the last place a block-move can happen. */
3789 {
3792 /* On targets with weird calling conventions (e.g. PA) it's
3793 hard to ensure that all cases of argument overlap between
3794 stack and registers work. Play it safe and bail out. */
3796 {
3799 }
3803 reg_parm_stack_space)
3808 }
3813 {
3816 }
3820 /* Figure out the register where the value, if any, will come back. */
3825 {
3827 {
3834 }
3835 else
3836 {
3841 fndecl,
3843 }
3845 /* If VALREG is a PARALLEL whose first member has a zero
3846 offset, use that. This is for targets such as m68k that
3847 return the same value in multiple places. */
3849 {
3856 }
3857 }
3859 /* Store all bounds not passed in registers. */
3861 {
3866 ? NULL
3868 }
3870 /* If register arguments require space on the stack and stack space
3871 was not preallocated, allocate stack space here for arguments
3872 passed in registers. */
3874 && !ACCUMULATE_OUTGOING_ARGS
3878 /* Pass the function the address in which to return a
3879 structure value. */
3881 {
3882 structure_value_addr
3887 NULL_RTX)));
3891 }
3901 /* Save a pointer to the last insn before the call, so that we can
3902 later safely search backwards to find the CALL_INSN. */
3905 /* Set up next argument register. For sibling calls on machines
3906 with register windows this should be the incoming register. */
3909 VOIDmode,
3910 void_type_node,
3912 else
3918 {
3924 && valreg
3927 call_fusage
3930 call_fusage);
3931 }
3932 /* All arguments and registers used for the call must be set up by
3933 now! */
3935 /* Stack must be properly aligned now. */
3939 /* Generate the actual call instruction. */
3946 {
3950 {
3954 }
3957 }
3959 /* If the call setup or the call itself overlaps with anything
3960 of the argument setup we probably clobbered our call address.
3961 In that case we can't do sibcalls. */
3966 /* If a non-BLKmode value is returned at the most significant end
3967 of a register, shift the register right by the appropriate amount
3968 and update VALREG accordingly. BLKmode values are handled by the
3969 group load/store machinery below. */
3971 && !pcc_struct_value
3976 {
3980 }
3983 {
3987 /* The return value from a malloc-like function is a pointer. */
3993 /* The return value from a malloc-like function can not alias
3994 anything else. */
3998 /* Write out the sequence. */
4003 }
4005 /* For calls to `setjmp', etc., inform
4006 function.c:setjmp_warnings that it should complain if
4007 nonvolatile values are live. For functions that cannot
4008 return, inform flow that control does not fall through. */
4011 {
4012 /* The barrier must be emitted
4013 immediately after the CALL_INSN. Some ports emit more
4014 than just a CALL_INSN above, so we must search for it here. */
4018 {
4020 /* There was no CALL_INSN? */
4022 }
4026 /* Stack adjustments after a noreturn call are dead code.
4027 However when NO_DEFER_POP is in effect, we must preserve
4028 stack_pointer_delta. */
4030 {
4033 }
4034 }
4036 /* If value type not void, return an rtx for the value. */
4042 {
4044 {
4045 target
4048 structure_value_addr));
4050 }
4051 }
4053 {
4054 /* This is the special C++ case where we need to
4055 know what the true target was. We take care to
4056 never use this value more than once in one expression. */
4060 }
4061 /* Handle calls that return values in multiple non-contiguous locations.
4062 The Irix 6 ABI has examples of this. */
4064 {
4068 ;
4070 /* Handle the result of a emit_group_move_into_temps
4071 call in the previous pass. */
4073 else
4076 }
4080 {
4083 /* We have to copy a return value in a CLASS_LIKELY_SPILLED hard
4084 reg to a plain register. */
4088 /* If TARGET is a MEM in the argument area, and we have
4089 saved part of the argument area, then we can't store
4090 directly into TARGET as it may get overwritten when we
4091 restore the argument save area below. Don't work too
4092 hard though and simply force TARGET to a register if it
4093 is a MEM; the optimizer is quite likely to sort it out. */
4097 {
4100 }
4104 else
4105 {
4106 /* TARGET and VALREG cannot be equal at this point
4107 because the latter would not have
4108 REG_FUNCTION_VALUE_P true, while the former would if
4109 it were referring to the same register.
4111 If they refer to the same register, this move will be
4112 a no-op, except when function inlining is being
4113 done. */
4116 /* If we are setting a MEM, this code must be executed.
4117 Since it is emitted after the call insn, sibcall
4118 optimization cannot be performed in that case. */
4121 }
4122 }
4123 else
4126 /* If we promoted this return value, make the proper SUBREG.
4127 TARGET might be const0_rtx here, so be careful. */
4131 {
4135 machine_mode pmode;
4137 /* Ensure we promote as expected, and get the new unsignedness. */
4145 {
4152 }
4157 }
4159 /* If size of args is variable or this was a constructor call for a stack
4160 argument, restore saved stack-pointer value. */
4163 {
4177 }
4179 {
4180 #ifdef REG_PARM_STACK_SPACE
4184 #endif
4186 /* If we saved any argument areas, restore them. */
4189 {
4191 rtx stack_area
4198 else
4201 BLOCK_OP_CALL_PARM);
4202 }
4206 }
4208 /* If this was alloca, record the new stack level. */
4212 /* Free up storage we no longer need. */
4222 {
4225 /* Restore the pending stack adjustment now that we have
4226 finished generating the sibling call sequence. */
4230 /* Prepare arg structure for next iteration. */
4232 {
4236 }
4241 }
4242 else
4243 {
4246 /* Verify that we've deallocated all the stack we used. */
4248 || (old_stack_allocated
4250 }
4252 /* If something prevents making this a sibling call,
4253 zero out the sequence. */
4256 else
4258 }
4260 /* If tail call production succeeded, we need to remove REG_EQUIV notes on
4261 arguments too, as argument area is now clobbered by the call. */
4263 {
4266 }
4267 else
4268 {
4271 /* Ideally we'd emit a message for all of the ways that it could
4272 have failed. */
4274 }
4276 currently_expanding_call--;
4281 /* Join result with returned bounds so caller may use them if needed. */
4285 }
4287 /* A sibling call sequence invalidates any REG_EQUIV notes made for
4288 this function's incoming arguments.
4290 At the start of RTL generation we know the only REG_EQUIV notes
4291 in the rtl chain are those for incoming arguments, so we can look
4292 for REG_EQUIV notes between the start of the function and the
4293 NOTE_INSN_FUNCTION_BEG.
4295 This is (slight) overkill. We could keep track of the highest
4296 argument we clobber and be more selective in removing notes, but it
4297 does not seem to be worth the effort. */
4299 void
4301 {
4305 {
4306 rtx note;
4308 /* There are never REG_EQUIV notes for the incoming arguments
4309 after the NOTE_INSN_FUNCTION_BEG note, so stop if we see it. */
4319 }
4320 }
4322 /* Traverse a list of TYPES and expand all complex types into their
4323 components. */
4324 static tree
4326 {
4327 tree p;
4329 /* Before allocating memory, check for the common case of no complex. */
4331 {
4336 }
4339 found:
4343 {
4348 {
4351 /* Rewrite complex type with component type. */
4355 /* Add another component type for the imaginary part. */
4360 /* Skip the newly created node. */
4362 }
4363 }
4366 }
4367 \f
4368 /* Output a library call to function FUN (a SYMBOL_REF rtx).
4369 The RETVAL parameter specifies whether return value needs to be saved, other
4370 parameters are documented in the emit_library_call function below. */
4372 static rtx
4376 {
4377 /* Total size in bytes of all the stack-parms scanned so far. */
4379 /* Size of arguments before any adjustments (such as rounding). */
4382 rtx fun;
4383 /* Todo, choose the correct decl type of orgfun. Sadly this information
4384 isn't present here, so we default to native calling abi here. */
4389 CUMULATIVE_ARGS args_so_far_v;
4390 cumulative_args_t args_so_far;
4391 struct arg
4392 {
4393 rtx value;
4394 machine_mode mode;
4395 rtx reg;
4398 rtx save_area;
4399 };
4404 rtx valreg;
4414 #ifdef REG_PARM_STACK_SPACE
4415 /* Define the boundary of the register parm stack space that needs to be
4416 save, if any. */
4419 #endif
4421 /* Size of the stack reserved for parameter registers. */
4428 #ifdef REG_PARM_STACK_SPACE
4430 #endif
4432 /* By default, library functions cannot throw. */
4436 {
4454 }
4457 /* Ensure current function's preferred stack boundary is at least
4458 what we need. */
4462 /* If this kind of value comes back in memory,
4463 decide where in memory it should come back. */
4465 {
4468 {
4469 #ifdef PCC_STATIC_STRUCT_RETURN
4470 rtx pointer_reg
4480 else
4482 #endif
4483 /* This call returns a big structure. */
4485 }
4486 }
4487 else
4490 /* ??? Unfinished: must pass the memory address as an argument. */
4492 /* Copy all the libcall-arguments out of the varargs data
4493 and into a vector ARGVEC.
4495 Compute how to pass each argument. We only support a very small subset
4496 of the full argument passing conventions to limit complexity here since
4497 library functions shouldn't have many args. */
4502 #ifdef INIT_CUMULATIVE_LIBCALL_ARGS
4504 #else
4506 #endif
4516 /* If there's a structure value address to be passed,
4517 either pass it in the special place, or pass it as an extra argument. */
4519 {
4522 nargs++;
4524 /* Make sure it is a reasonable operand for a move or push insn. */
4540 #ifdef STACK_PARMS_IN_REG_PARM_AREA
4542 #else
4544 #endif
4554 count++;
4555 }
4558 {
4563 /* We cannot convert the arg value to the mode the library wants here;
4564 must do it earlier where we know the signedness of the arg. */
4568 /* Make sure it is a reasonable operand for a move or push insn. */
4574 {
4575 rtx slot;
4576 int must_copy
4579 /* If this was a CONST function, it is now PURE since it now
4580 reads memory. */
4582 {
4585 }
4588 {
4593 }
4594 else
4595 {
4599 }
4603 call_fusage);
4607 slot),
4608 call_fusage);
4612 }
4626 {
4628 #ifdef STACK_PARMS_IN_REG_PARM_AREA
4630 #else
4632 #endif
4637 }
4638 #ifdef BLOCK_REG_PADDING
4639 else
4640 /* The argument is passed entirely in registers. See at which
4641 end it should be padded. */
4645 #endif
4648 }
4650 /* If this machine requires an external definition for library
4651 functions, write one out. */
4656 + stack_pointer_delta
4658 / STACK_BYTES
4663 reg_parm_stack_space);
4672 {
4676 }
4679 {
4680 /* Since the stack pointer will never be pushed, it is possible for
4681 the evaluation of a parm to clobber something we have already
4682 written to the stack. Since most function calls on RISC machines
4683 do not use the stack, this is uncommon, but must work correctly.
4685 Therefore, we save any area of the stack that was already written
4686 and that we are using. Here we set up to do this by making a new
4687 stack usage map from the old one.
4689 Another approach might be to try to reorder the argument
4690 evaluations to avoid this conflicting stack usage. */
4694 /* Since we will be writing into the entire argument area, the
4695 map must be allocated for its entire size, not just the part that
4696 is the responsibility of the caller. */
4703 else
4711 initial_highest_arg_in_use);
4718 /* We must be careful to use virtual regs before they're instantiated,
4719 and real regs afterwards. Loop optimization, for example, can create
4720 new libcalls after we've instantiated the virtual regs, and if we
4721 use virtuals anyway, they won't match the rtl patterns. */
4725 STACK_POINTER_OFFSET);
4726 else
4728 }
4729 else
4730 {
4733 }
4735 /* We push args individually in reverse order, perform stack alignment
4736 before the first push (the last arg). */
4743 #ifdef REG_PARM_STACK_SPACE
4745 {
4746 /* The argument list is the property of the called routine and it
4747 may clobber it. If the fixed area has been used for previous
4748 parameters, we must save and restore it. */
4751 }
4752 #endif
4754 /* When expanding a normal call, args are stored in push order,
4755 which is the reverse of what we have here. */
4759 {
4762 }
4766 /* Push the args that need to be pushed. */
4770 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
4771 are to be pushed. */
4773 {
4782 {
4783 rtx use;
4786 {
4787 /* If this is being stored into a pre-allocated, fixed-size,
4788 stack area, save any previous data at that location. */
4791 {
4792 /* stack_slot is negative, but we want to index stack_usage_map
4793 with positive values. */
4796 }
4797 else
4798 {
4801 }
4804 /* Don't worry about things in the fixed argument area;
4805 it has already been saved. */
4809 i++;
4812 {
4813 /* We need to make a save area. */
4814 unsigned int size
4816 machine_mode save_mode
4818 rtx adr
4821 rtx stack_area
4825 {
4829 );
4833 stack_area,
4835 BLOCK_OP_CALL_PARM);
4836 }
4837 else
4838 {
4842 }
4843 }
4844 }
4849 reg_parm_stack_space,
4852 /* Now mark the segment we just used. */
4857 NO_DEFER_POP;
4859 /* Indicate argument access so that alias.c knows that these
4860 values are live. */
4866 else
4867 {
4868 /* When arguments are pushed, trying to tell alias.c where
4869 exactly this argument is won't work, because the
4870 auto-increment causes confusion. So we merely indicate
4871 that we access something with a known mode somewhere on
4872 the stack. */
4876 }
4880 }
4881 }
4887 /* Now load any reg parms into their regs. */
4889 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
4890 are to be pushed. */
4892 {
4897 #ifdef BLOCK_REG_PADDING
4899 #endif
4901 /* Handle calls that pass values in multiple non-contiguous
4902 locations. The PA64 has examples of this for library calls. */
4906 {
4908 #ifdef BLOCK_REG_PADDING
4911 /* Copied from load_register_parameters. */
4913 /* Handle case where we have a value that needs shifting
4914 up to the msb. eg. a QImode value and we're padding
4915 upward on a BYTES_BIG_ENDIAN machine. */
4919 {
4920 rtx x;
4923 /* Assigning REG here rather than a temp makes CALL_FUSAGE
4924 report the whole reg as used. Strictly speaking, the
4925 call only uses SIZE bytes at the msb end, but it doesn't
4926 seem worth generating rtl to say that. */
4931 }
4932 #endif
4933 }
4935 NO_DEFER_POP;
4936 }
4938 /* Any regs containing parms remain in use through the call. */
4940 {
4945 {
4948 {
4953 }
4954 else
4956 }
4957 }
4959 /* Pass the function the address in which to return a structure value. */
4961 {
4965 NULL_RTX)));
4968 }
4970 /* Don't allow popping to be deferred, since then
4971 cse'ing of library calls could delete a call and leave the pop. */
4972 NO_DEFER_POP;
4976 /* Stack must be properly aligned now. */
4982 /* We pass the old value of inhibit_defer_pop + 1 to emit_call_1, which
4983 will set inhibit_defer_pop to that value. */
4984 /* The return type is needed to decide how many bytes the function pops.
4985 Signedness plays no role in that, so for simplicity, we pretend it's
4986 always signed. We also assume that the list of arguments passed has
4987 no impact, so we pretend it is unknown. */
4993 struct_value_size,
4996 valreg,
5000 {
5005 }
5007 /* Right-shift returned value if necessary. */
5011 {
5014 }
5018 /* For calls to `setjmp', etc., inform function.c:setjmp_warnings
5019 that it should complain if nonvolatile values are live. For
5020 functions that cannot return, inform flow that control does not
5021 fall through. */
5023 {
5024 /* The barrier note must be emitted
5025 immediately after the CALL_INSN. Some ports emit more than
5026 just a CALL_INSN above, so we must search for it here. */
5029 {
5031 /* There was no CALL_INSN? */
5033 }
5036 }
5038 /* Consider that "regular" libcalls, i.e. all of them except for LCT_THROW
5039 and LCT_RETURNS_TWICE, cannot perform non-local gotos. */
5041 {
5044 {
5046 /* There was no CALL_INSN? */
5048 }
5051 }
5053 /* Now restore inhibit_defer_pop to its actual original value. */
5054 OK_DEFER_POP;
5058 /* Copy the value to the right place. */
5060 {
5062 {
5067 }
5069 {
5073 }
5074 else
5075 {
5076 /* Convert to the proper mode if a promotion has been active. */
5078 {
5085 }
5089 else
5091 }
5092 }
5095 {
5096 #ifdef REG_PARM_STACK_SPACE
5100 #endif
5102 /* If we saved any argument areas, restore them. */
5105 {
5114 validize_mem
5117 BLOCK_OP_CALL_PARM);
5118 else
5120 }
5124 }
5130 }
5131 \f
5132 /* Output a library call to function FUN (a SYMBOL_REF rtx)
5133 (emitting the queue unless NO_QUEUE is nonzero),
5134 for a value of mode OUTMODE,
5135 with NARGS different arguments, passed as alternating rtx values
5136 and machine_modes to convert them to.
5138 FN_TYPE should be LCT_NORMAL for `normal' calls, LCT_CONST for
5139 `const' calls, LCT_PURE for `pure' calls, or other LCT_ value for
5140 other types of library calls. */
5142 void
5145 {
5151 }
5152 \f
5153 /* Like emit_library_call except that an extra argument, VALUE,
5154 comes second and says where to store the result.
5155 (If VALUE is zero, this function chooses a convenient way
5156 to return the value.
5158 This function returns an rtx for where the value is to be found.
5159 If VALUE is nonzero, VALUE is returned. */
5161 rtx
5165 {
5166 rtx result;
5175 }
5176 \f
5178 /* Store pointer bounds argument ARG into Bounds Table entry
5179 associated with PARM. */
5180 static void
5182 {
5185 /* We may pass bounds not associated with any pointer. */
5187 {
5191 }
5192 /* Find pointer associated with bounds and where it is
5193 passed. */
5194 else
5195 {
5197 {
5201 }
5203 {
5211 else
5212 {
5215 }
5216 }
5217 else
5218 {
5227 else
5229 }
5230 }
5232 /* Expand bounds. */
5237 }
5239 /* Store a single argument for a function call
5240 into the register or memory area where it must be passed.
5241 *ARG describes the argument value and where to pass it.
5243 ARGBLOCK is the address of the stack-block for all the arguments,
5244 or 0 on a machine where arguments are pushed individually.
5246 MAY_BE_ALLOCA nonzero says this could be a call to `alloca'
5247 so must be careful about how the stack is used.
5249 VARIABLE_SIZE nonzero says that this was a variable-sized outgoing
5250 argument stack. This is used if ACCUMULATE_OUTGOING_ARGS to indicate
5251 that we need not worry about saving and restoring the stack.
5253 FNDECL is the declaration of the function we are calling.
5255 Return nonzero if this arg should cause sibcall failure,
5256 zero otherwise. */
5258 static int
5261 {
5272 /* Push a new temporary level for any temporaries we make for
5273 this argument. */
5277 {
5278 /* If this is being stored into a pre-allocated, fixed-size, stack area,
5279 save any previous data at that location. */
5281 {
5283 {
5284 /* stack_slot is negative, but we want to index stack_usage_map
5285 with positive values. */
5288 else
5292 }
5293 else
5294 {
5297 else
5301 }
5304 /* Don't worry about things in the fixed argument area;
5305 it has already been saved. */
5309 i++;
5312 {
5313 /* We need to make a save area. */
5320 {
5321 arg->save_area
5325 stack_area,
5327 BLOCK_OP_CALL_PARM);
5328 }
5329 else
5330 {
5333 }
5334 }
5335 }
5336 }
5338 /* If this isn't going to be placed on both the stack and in registers,
5339 set up the register and number of words. */
5341 {
5344 else
5347 }
5349 /* Being passed entirely in a register. We shouldn't be called in
5350 this case. */
5353 /* If this arg needs special alignment, don't load the registers
5354 here. */
5358 /* If this is being passed partially in a register, we can't evaluate
5359 it directly into its stack slot. Otherwise, we can. */
5361 {
5362 /* stack_arg_under_construction is nonzero if a function argument is
5363 being evaluated directly into the outgoing argument list and
5364 expand_call must take special action to preserve the argument list
5365 if it is called recursively.
5367 For scalar function arguments stack_usage_map is sufficient to
5368 determine which stack slots must be saved and restored. Scalar
5369 arguments in general have pass_on_stack == 0.
5371 If this argument is initialized by a function which takes the
5372 address of the argument (a C++ constructor or a C function
5373 returning a BLKmode structure), then stack_usage_map is
5374 insufficient and expand_call must push the stack around the
5375 function call. Such arguments have pass_on_stack == 1.
5377 Note that it is always safe to set stack_arg_under_construction,
5378 but this generates suboptimal code if set when not needed. */
5381 stack_arg_under_construction++;
5384 (partial
5389 /* If we are promoting object (or for any other reason) the mode
5390 doesn't agree, convert the mode. */
5397 stack_arg_under_construction--;
5398 }
5400 /* Check for overlap with already clobbered argument area. */
5407 /* Don't allow anything left on stack from computation
5408 of argument to alloca. */
5413 /* If the value is already in the stack slot, we are done. */
5414 ;
5416 {
5420 /* Argument is a scalar, not entirely passed in registers.
5421 (If part is passed in registers, arg->partial says how much
5422 and emit_push_insn will take care of putting it there.)
5424 Push it, and if its size is less than the
5425 amount of space allocated to it,
5426 also bump stack pointer by the additional space.
5427 Note that in C the default argument promotions
5428 will prevent such mismatches. */
5431 /* Compute how much space the push instruction will push.
5432 On many machines, pushing a byte will advance the stack
5433 pointer by a halfword. */
5434 #ifdef PUSH_ROUNDING
5436 #endif
5439 /* Compute how much space the argument should get:
5440 round up to a multiple of the alignment for arguments. */
5446 /* Compute the alignment of the pushed argument. */
5449 {
5452 {
5455 }
5456 }
5458 /* This isn't already where we want it on the stack, so put it there.
5459 This can either be done with push or copy insns. */
5466 /* Unless this is a partially-in-register argument, the argument is now
5467 in the stack. */
5470 }
5471 else
5472 {
5473 /* BLKmode, at least partly to be pushed. */
5477 rtx size_rtx;
5479 /* Pushing a nonscalar.
5480 If part is passed in registers, PARTIAL says how much
5481 and emit_push_insn will take care of putting it there. */
5483 /* Round its size up to a multiple
5484 of the allocation unit for arguments. */
5487 {
5490 }
5491 else
5492 {
5493 /* PUSH_ROUNDING has no effect on us, because emit_push_insn
5494 for BLKmode is careful to avoid it. */
5500 EXPAND_NORMAL);
5501 }
5505 /* When an argument is padded down, the block is aligned to
5506 PARM_BOUNDARY, but the actual argument isn't. */
5508 {
5512 {
5515 }
5516 }
5519 {
5520 /* emit_push_insn might not work properly if arg->value and
5521 argblock + arg->locate.offset areas overlap. */
5530 {
5534 /* arg.locate doesn't contain the pretend_args_size offset,
5535 it's part of argblock. Ensure we don't count it in I. */
5538 else
5541 /* expand_call should ensure this. */
5547 {
5550 }
5552 {
5553 /* Use arg->locate.size.constant instead of size_rtx
5554 because we only care about the part of the argument
5555 on the stack. */
5559 }
5560 else
5561 {
5562 /* Even though they appear to be at the same location,
5563 if part of the outgoing argument is in registers,
5564 they aren't really at the same location. Check for
5565 this by making sure that the incoming size is the
5566 same as the outgoing size. */
5569 }
5570 }
5571 }
5578 /* Unless this is a partially-in-register argument, the argument is now
5579 in the stack.
5581 ??? Unlike the case above, in which we want the actual
5582 address of the data, so that we can load it directly into a
5583 register, here we want the address of the stack slot, so that
5584 it's properly aligned for word-by-word copying or something
5585 like that. It's not clear that this is always correct. */
5588 }
5591 {
5593 arg->parallel_value
5596 }
5598 /* Mark all slots this store used. */
5604 /* Once we have pushed something, pops can't safely
5605 be deferred during the rest of the arguments. */
5606 NO_DEFER_POP;
5608 /* Free any temporary slots made in processing this argument. */
5612 }
5614 /* Nonzero if we do not know how to pass TYPE solely in registers. */
5616 bool
5618 const_tree type)
5619 {
5623 /* If the type has variable size... */
5627 /* If the type is marked as addressable (it is required
5628 to be constructed into the stack)... */
5633 }
5635 /* Another version of the TARGET_MUST_PASS_IN_STACK hook. This one
5636 takes trailing padding of a structure into account. */
5637 /* ??? Should be able to merge these two by examining BLOCK_REG_PADDING. */
5639 bool
5641 {
5645 /* If the type has variable size... */
5649 /* If the type is marked as addressable (it is required
5650 to be constructed into the stack)... */
5654 /* If the padding and mode of the type is such that a copy into
5655 a register would put it into the wrong part of the register. */
5663 }
5665 /* Tell the garbage collector about GTY markers in this source file. */