| blob | 530e7bf219dfff6813ca7119ab3adcb21f0e894c |
1 /* Convert function calls to rtl insns, for GNU C compiler.
2 Copyright (C) 1989-2016 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/>. */
54 /* Like PREFERRED_STACK_BOUNDARY but in units of bytes, not bits. */
55 #define STACK_BYTES (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT)
57 /* Data structure and subroutines used within expand_call. */
59 struct arg_data
60 {
61 /* Tree node for this argument. */
62 tree tree_value;
63 /* Mode for value; TYPE_MODE unless promoted. */
64 machine_mode mode;
65 /* Current RTL value for argument, or 0 if it isn't precomputed. */
66 rtx value;
67 /* Initially-compute RTL value for argument; only for const functions. */
68 rtx initial_value;
69 /* Register to pass this argument in, 0 if passed on stack, or an
70 PARALLEL if the arg is to be copied into multiple non-contiguous
71 registers. */
72 rtx reg;
73 /* Register to pass this argument in when generating tail call sequence.
74 This is not the same register as for normal calls on machines with
75 register windows. */
76 rtx tail_call_reg;
77 /* If REG is a PARALLEL, this is a copy of VALUE pulled into the correct
78 form for emit_group_move. */
79 rtx parallel_value;
80 /* If value is passed in neither reg nor stack, this field holds a number
81 of a special slot to be used. */
82 rtx special_slot;
83 /* For pointer bounds hold an index of parm bounds are bound to. -1 if
84 there is no such pointer. */
86 /* If pointer_arg refers a structure, then pointer_offset holds an offset
87 of a pointer in this structure. */
89 /* If REG was promoted from the actual mode of the argument expression,
90 indicates whether the promotion is sign- or zero-extended. */
92 /* Number of bytes to put in registers. 0 means put the whole arg
93 in registers. Also 0 if not passed in registers. */
95 /* Nonzero if argument must be passed on stack.
96 Note that some arguments may be passed on the stack
97 even though pass_on_stack is zero, just because FUNCTION_ARG says so.
98 pass_on_stack identifies arguments that *cannot* go in registers. */
100 /* Some fields packaged up for locate_and_pad_parm. */
102 /* Location on the stack at which parameter should be stored. The store
103 has already been done if STACK == VALUE. */
104 rtx stack;
105 /* Location on the stack of the start of this argument slot. This can
106 differ from STACK if this arg pads downward. This location is known
107 to be aligned to TARGET_FUNCTION_ARG_BOUNDARY. */
108 rtx stack_slot;
109 /* Place that this stack area has been saved, if needed. */
110 rtx save_area;
111 /* If an argument's alignment does not permit direct copying into registers,
112 copy in smaller-sized pieces into pseudos. These are stored in a
113 block pointed to by this field. The next field says how many
114 word-sized pseudos we made. */
117 };
119 /* A vector of one char per byte of stack space. A byte if nonzero if
120 the corresponding stack location has been used.
121 This vector is used to prevent a function call within an argument from
122 clobbering any stack already set up. */
125 /* Size of STACK_USAGE_MAP. */
128 /* A bitmap of virtual-incoming stack space. Bit is set if the corresponding
129 stack location's tail call argument has been already stored into the stack.
130 This bitmap is used to prevent sibling call optimization if function tries
131 to use parent's incoming argument slots when they have been already
132 overwritten with tail call arguments. */
135 /* stack_arg_under_construction is nonzero when an argument may be
136 initialized with a constructor call (including a C function that
137 returns a BLKmode struct) and expand_call must take special action
138 to make sure the object being constructed does not overlap the
139 argument list for the constructor call. */
144 cumulative_args_t);
173 #ifdef REG_PARM_STACK_SPACE
176 #endif
177 \f
178 /* Force FUNEXP into a form suitable for the address of a CALL,
179 and return that as an rtx. Also load the static chain register
180 if FNDECL is a nested function.
182 CALL_FUSAGE points to a variable holding the prospective
183 CALL_INSN_FUNCTION_USAGE information. */
185 rtx
188 {
189 /* Make a valid memory address and copy constants through pseudo-regs,
190 but not for a constant address if -fno-function-cse. */
192 {
193 /* If it's an indirect call by descriptor, generate code to perform
194 runtime identification of the pointer and load the descriptor. */
196 {
201 fndecl_or_type
203 fndecl_or_type);
207 /* Avoid long live ranges around function calls. */
213 /* Emit the runtime identification pattern. */
216 call_lab);
218 /* Statically predict the branch to very likely taken. */
223 /* Load the descriptor. */
232 POINTER_SIZE / BITS_PER_UNIT
241 {
244 }
246 /* Make sure we're not going to be overwritten below. */
248 }
250 /* If we are using registers for parameters, force the
251 function address into a register now. */
252 funexp = ((reg_parm_seen
256 }
257 else
258 {
259 /* funexp could be a SYMBOL_REF represents a function pointer which is
260 of ptr_mode. In this case, it should be converted into address mode
261 to be a valid address for memory rtx pattern. See PR 64971. */
266 {
269 }
270 }
275 {
276 rtx chain;
283 {
286 }
287 }
290 }
292 /* Generate instructions to call function FUNEXP,
293 and optionally pop the results.
294 The CALL_INSN is the first insn generated.
296 FNDECL is the declaration node of the function. This is given to the
297 hook TARGET_RETURN_POPS_ARGS to determine whether this function pops
298 its own args.
300 FUNTYPE is the data type of the function. This is given to the hook
301 TARGET_RETURN_POPS_ARGS to determine whether this function pops its
302 own args. We used to allow an identifier for library functions, but
303 that doesn't work when the return type is an aggregate type and the
304 calling convention says that the pointer to this aggregate is to be
305 popped by the callee.
307 STACK_SIZE is the number of bytes of arguments on the stack,
308 ROUNDED_STACK_SIZE is that number rounded up to
309 PREFERRED_STACK_BOUNDARY; zero if the size is variable. This is
310 both to put into the call insn and to generate explicit popping
311 code if necessary.
313 STRUCT_VALUE_SIZE is the number of bytes wanted in a structure value.
314 It is zero if this call doesn't want a structure value.
316 NEXT_ARG_REG is the rtx that results from executing
317 targetm.calls.function_arg (&args_so_far, VOIDmode, void_type_node, true)
318 just after all the args have had their registers assigned.
319 This could be whatever you like, but normally it is the first
320 arg-register beyond those used for args in this call,
321 or 0 if all the arg-registers are used in this call.
322 It is passed on to `gen_call' so you can put this info in the call insn.
324 VALREG is a hard register in which a value is returned,
325 or 0 if the call does not return a value.
327 OLD_INHIBIT_DEFER_POP is the value that `inhibit_defer_pop' had before
328 the args to this call were processed.
329 We restore `inhibit_defer_pop' to that value.
331 CALL_FUSAGE is either empty or an EXPR_LIST of USE expressions that
332 denote registers used by the called function. */
334 static void
336 tree funtype ATTRIBUTE_UNUSED,
337 HOST_WIDE_INT stack_size ATTRIBUTE_UNUSED,
338 HOST_WIDE_INT rounded_stack_size,
339 HOST_WIDE_INT struct_value_size ATTRIBUTE_UNUSED,
342 cumulative_args_t args_so_far ATTRIBUTE_UNUSED)
343 {
349 /* Sibling call patterns never pop arguments (no sibcall(_value)_pop
350 patterns exist). Any popping that the callee does on return will
351 be from our caller's frame rather than ours. */
353 {
356 #ifdef CALL_POPS_ARGS
358 #endif
359 }
361 /* Ensure address is valid. SYMBOL_REF is already valid, so no need,
362 and we don't want to load it into a register as an optimization,
363 because prepare_call_address already did it if it should be done. */
369 {
372 /* Although a built-in FUNCTION_DECL and its non-__builtin
373 counterpart compare equal and get a shared mem_attrs, they
374 produce different dump output in compare-debug compilations,
375 if an entry gets garbage collected in one compilation, then
376 adds a different (but equivalent) entry, while the other
377 doesn't run the garbage collector at the same spot and then
378 shares the mem_attr with the equivalent entry. */
380 {
384 }
387 }
392 {
395 rounded_stack_size_rtx,
397 else
400 }
401 /* If the target has "call" or "call_value" insns, then prefer them
402 if no arguments are actually popped. If the target does not have
403 "call" or "call_value" insns, then we must use the popping versions
404 even if the call has no arguments to pop. */
406 || !(valreg
409 {
412 /* If this subroutine pops its own args, record that in the call insn
413 if possible, for the sake of frame pointer elimination. */
417 rounded_stack_size_rtx,
419 else
424 }
425 else
426 {
430 else
433 }
436 /* Find the call we just emitted. */
439 /* Some target create a fresh MEM instead of reusing the one provided
440 above. Set its MEM_EXPR. */
447 /* Mark instrumented calls. */
451 /* Put the register usage information there. */
454 /* If this is a const call, then set the insn's unchanging bit. */
458 /* If this is a pure call, then set the insn's unchanging bit. */
462 /* If this is a const call, then set the insn's unchanging bit. */
466 /* Create a nothrow REG_EH_REGION note, if needed. */
473 {
476 }
480 /* Restore this now, so that we do defer pops for this call's args
481 if the context of the call as a whole permits. */
485 {
497 /* If popup is needed, stack realign must use DRAP */
500 }
501 /* For noreturn calls when not accumulating outgoing args force
502 REG_ARGS_SIZE note to prevent crossjumping of calls with different
503 args sizes. */
508 {
509 /* If returning from the subroutine does not automatically pop the args,
510 we need an instruction to pop them sooner or later.
511 Perhaps do it now; perhaps just record how much space to pop later.
513 If returning from the subroutine does pop the args, indicate that the
514 stack pointer will be changed. */
517 {
519 /* Just pretend we did the pop. */
524 else
526 }
527 }
528 /* When we accumulate outgoing args, we must avoid any stack manipulations.
529 Restore the stack pointer to its original value now. Usually
530 ACCUMULATE_OUTGOING_ARGS targets don't get here, but there are exceptions.
531 On i386 ACCUMULATE_OUTGOING_ARGS can be enabled on demand, and
532 popping variants of functions exist as well.
534 ??? We may optimize similar to defer_pop above, but it is
535 probably not worthwhile.
537 ??? It will be worthwhile to enable combine_stack_adjustments even for
538 such machines. */
541 }
543 /* Determine if the function identified by FNDECL is one with
544 special properties we wish to know about. Modify FLAGS accordingly.
546 For example, if the function might return more than one time (setjmp), then
547 set ECF_RETURNS_TWICE.
549 Set ECF_MAY_BE_ALLOCA for any memory allocation function that might allocate
550 space from the stack such as alloca. */
552 static int
554 {
557 /* For instrumentation clones we want to derive flags
558 from the original name. */
565 /* Exclude functions not at the file scope, or not `extern',
566 since they are not the magic functions we would otherwise
567 think they are.
568 FIXME: this should be handled with attributes, not with this
569 hacky imitation of DECL_ASSEMBLER_NAME. It's (also) wrong
570 because you can declare fork() inside a function if you
571 wish. */
575 {
579 /* We assume that alloca will always be called by name. It
580 makes no sense to pass it as a pointer-to-function to
581 anything that does not understand its behavior. */
587 /* Disregard prefix _ or __. */
589 {
592 else
594 }
596 /* ECF_RETURNS_TWICE is safe even for -ffreestanding. */
603 }
607 {
614 }
617 }
619 /* Similar to special_function_p; return a set of ERF_ flags for the
620 function FNDECL. */
621 static int
623 {
624 tree attr;
638 {
651 }
652 }
654 /* Return nonzero when FNDECL represents a call to setjmp. */
656 int
658 {
662 }
665 /* Return true if STMT may be an alloca call. */
667 bool
669 {
670 tree fndecl;
680 }
682 /* Return true if STMT is a builtin alloca call. */
684 bool
686 {
687 tree fndecl;
695 {
701 }
704 }
706 /* Return true when exp contains a builtin alloca call. */
708 bool
710 {
711 tree fndecl;
716 {
722 }
725 }
727 /* Return TRUE if FNDECL is either a TM builtin or a TM cloned
728 function. Return FALSE otherwise. */
730 static bool
732 {
740 {
742 {
785 }
786 }
788 }
790 /* Detect flags (function attributes) from the function decl or type node. */
792 int
794 {
798 {
799 /* The function exp may have the `malloc' attribute. */
803 /* The function exp may have the `returns_twice' attribute. */
807 /* Process the pure and const attributes. */
824 {
831 }
834 }
836 {
844 }
845 else
849 {
853 }
856 }
858 /* Detect flags from a CALL_EXPR. */
860 int
862 {
870 else
871 {
875 else
879 }
882 }
884 /* Return true if TYPE should be passed by invisible reference. */
886 bool
889 {
891 {
892 /* If this type contains non-trivial constructors, then it is
893 forbidden for the middle-end to create any new copies. */
897 /* GCC post 3.4 passes *all* variable sized types by reference. */
901 /* If a record type should be passed the same as its first (and only)
902 member, use the type and mode of that member. */
904 {
907 }
908 }
912 }
914 /* Return true if TYPE, which is passed by reference, should be callee
915 copied instead of caller copied. */
917 bool
920 {
924 named_arg);
925 }
928 /* Precompute all register parameters as described by ARGS, storing values
929 into fields within the ARGS array.
931 NUM_ACTUALS indicates the total number elements in the ARGS array.
933 Set REG_PARM_SEEN if we encounter a register parameter. */
935 static void
938 {
945 {
949 {
954 }
956 /* If we are to promote the function arg to a wider mode,
957 do it now. */
965 /* If the value is a non-legitimate constant, force it into a
966 pseudo now. TLS symbols sometimes need a call to resolve. */
971 /* If we're going to have to load the value by parts, pull the
972 parts into pseudos. The part extraction process can involve
973 non-trivial computation. */
975 {
980 }
982 /* If the value is expensive, and we are inside an appropriately
983 short loop, put the value into a pseudo and then put the pseudo
984 into the hard reg.
986 For small register classes, also do this if this call uses
987 register parameters. This is to avoid reload conflicts while
988 loading the parameters registers. */
997 && ((*reg_parm_seen
1001 }
1002 }
1004 #ifdef REG_PARM_STACK_SPACE
1006 /* The argument list is the property of the called routine and it
1007 may clobber it. If the fixed area has been used for previous
1008 parameters, we must save and restore it. */
1010 static rtx
1011 save_fixed_argument_area (int reg_parm_stack_space, rtx argblock, int *low_to_save, int *high_to_save)
1012 {
1016 /* Compute the boundary of the area that needs to be saved, if any. */
1026 {
1028 machine_mode save_mode;
1030 rtx addr;
1031 rtx stack_area;
1032 rtx save_area;
1035 ;
1043 /* If we don't have the required alignment, must do this
1044 in BLKmode. */
1051 else
1059 {
1063 }
1064 else
1065 {
1068 }
1071 }
1074 }
1076 static void
1078 {
1085 else
1094 else
1097 BLOCK_OP_CALL_PARM);
1098 }
1101 /* If any elements in ARGS refer to parameters that are to be passed in
1102 registers, but not in memory, and whose alignment does not permit a
1103 direct copy into registers. Copy the values into a group of pseudos
1104 which we will later copy into the appropriate hard registers.
1106 Pseudos for each unaligned argument will be stored into the array
1107 args[argnum].aligned_regs. The caller is responsible for deallocating
1108 the aligned_regs array if it is nonzero. */
1110 static void
1112 {
1122 {
1127 {
1130 }
1131 else
1132 {
1135 }
1139 /* Structures smaller than a word are normally aligned to the
1140 least significant byte. On a BYTES_BIG_ENDIAN machine,
1141 this means we must skip the empty high order bytes when
1142 calculating the bit offset. */
1144 #ifdef BLOCK_REG_PADDING
1148 #else
1149 && BYTES_BIG_ENDIAN
1150 #endif
1151 )
1155 {
1164 /* There is no need to restrict this code to loading items
1165 in TYPE_ALIGN sized hunks. The bitfield instructions can
1166 load up entire word sized registers efficiently.
1168 ??? This may not be needed anymore.
1169 We use to emit a clobber here but that doesn't let later
1170 passes optimize the instructions we emit. By storing 0 into
1171 the register later passes know the first AND to zero out the
1172 bitfield being set in the register is unnecessary. The store
1173 of 0 will be deleted as will at least the first AND. */
1180 }
1181 }
1182 }
1184 /* Issue an error if CALL_EXPR was flagged as requiring
1185 tall-call optimization. */
1187 static void
1189 {
1195 }
1197 /* Fill in ARGS_SIZE and ARGS array based on the parameters found in
1198 CALL_EXPR EXP.
1200 NUM_ACTUALS is the total number of parameters.
1202 N_NAMED_ARGS is the total number of named arguments.
1204 STRUCT_VALUE_ADDR_VALUE is the implicit argument for a struct return
1205 value, or null.
1207 FNDECL is the tree code for the target of this call (if known)
1209 ARGS_SO_FAR holds state needed by the target to know where to place
1210 the next argument.
1212 REG_PARM_STACK_SPACE is the number of bytes of stack space reserved
1213 for arguments which are passed in registers.
1215 OLD_STACK_LEVEL is a pointer to an rtx which olds the old stack level
1216 and may be modified by this routine.
1218 OLD_PENDING_ADJ, MUST_PREALLOCATE and FLAGS are pointers to integer
1219 flags which may be modified by this routine.
1221 MAY_TAILCALL is cleared if we encounter an invisible pass-by-reference
1222 that requires allocation of stack space.
1224 CALL_FROM_THUNK_P is true if this call is the jump from a thunk to
1225 the thunked-to function. */
1227 static void
1234 cumulative_args_t args_so_far,
1239 {
1243 /* Count arg position in order args appear. */
1253 /* In this loop, we consider args in the order they are written.
1254 We fill up ARGS from the back. */
1257 {
1259 call_expr_arg_iterator iter;
1260 tree arg;
1264 {
1266 j--;
1268 /* If we pass structure address then we need to
1269 create bounds for it. Since created bounds is
1270 a call statement, we expand it right here to avoid
1271 fixing all other places where it may be expanded. */
1273 {
1280 j--;
1281 }
1282 }
1285 {
1288 /* Remember last param with pointer and associate it
1289 with following pointer bounds. */
1292 {
1297 {
1300 }
1301 }
1305 {
1309 }
1311 {
1312 /* We expect bounds in instrumented calls only.
1313 Otherwise it is a sign we lost flag due to some optimization
1314 and may emit call args incorrectly. */
1317 /* For structures look for the next available pointer. */
1319 {
1326 /* Check we have no more pointers in the structure. */
1329 }
1332 /* Check we covered all pointers in the previous
1333 non bounds arg. */
1336 }
1337 else
1341 && argtype
1344 {
1347 j--;
1349 }
1350 else
1352 j--;
1353 argpos++;
1354 }
1358 }
1362 /* I counts args in order (to be) pushed; ARGPOS counts in order written. */
1364 {
1367 machine_mode mode;
1369 /* Replace erroneous argument with constant zero. */
1373 /* If TYPE is a transparent union or record, pass things the way
1374 we would pass the first field of the union or record. We have
1375 already verified that the modes are the same. */
1380 /* Decide where to pass this arg.
1382 args[i].reg is nonzero if all or part is passed in registers.
1384 args[i].partial is nonzero if part but not all is passed in registers,
1385 and the exact value says how many bytes are passed in registers.
1387 args[i].pass_on_stack is nonzero if the argument must at least be
1388 computed on the stack. It may then be loaded back into registers
1389 if args[i].reg is nonzero.
1391 These decisions are driven by the FUNCTION_... macros and must agree
1392 with those made by function.c. */
1394 /* See if this argument should be passed by invisible reference. */
1397 {
1401 callee_copies
1405 /* If we're compiling a thunk, pass through invisible references
1406 instead of making a copy. */
1408 || (callee_copies
1413 {
1414 /* We may have turned the parameter value into an SSA name.
1415 Go back to the original parameter so we can take the
1416 address. */
1418 {
1422 }
1423 /* Argument setup code may have copied the value to register. We
1424 revert that optimization now because the tail call code must
1425 use the original location. */
1435 /* We can't use sibcalls if a callee-copied argument is
1436 stored in the current function's frame. */
1438 {
1441 "a callee-copied argument is"
1442 " stored in the current "
1444 }
1452 }
1453 else
1454 {
1455 /* We make a copy of the object and pass the address to the
1456 function being called. */
1457 rtx copy;
1464 {
1465 /* This is a variable-sized object. Make space on the stack
1466 for it. */
1470 {
1474 }
1476 /* We can pass TRUE as the 4th argument because we just
1477 saved the stack pointer and will restore it right after
1478 the call. */
1485 }
1486 else
1491 /* Just change the const function to pure and then let
1492 the next test clear the pure based on
1493 callee_copies. */
1495 {
1498 }
1508 "argument must be passed"
1510 }
1511 }
1524 {
1527 }
1529 /* If this is a sibling call and the machine has register windows, the
1530 register window has to be unwinded before calling the routine, so
1531 arguments have to go into the incoming registers. */
1536 else
1546 /* If FUNCTION_ARG returned a (parallel [(expr_list (nil) ...) ...]),
1547 it means that we are to pass this arg in the register(s) designated
1548 by the PARALLEL, but also to pass it in the stack. */
1553 /* If this is an addressable type, we must preallocate the stack
1554 since we must evaluate the object into its final location.
1556 If this is to be passed in both registers and the stack, it is simpler
1557 to preallocate. */
1562 /* No stack allocation and padding for bounds. */
1564 ;
1565 /* Compute the stack-size of this argument. */
1570 #ifdef STACK_PARMS_IN_REG_PARM_AREA
1572 #else
1574 #endif
1575 reg_parm_stack_space,
1578 #ifdef BLOCK_REG_PADDING
1579 else
1580 /* The argument is passed entirely in registers. See at which
1581 end it should be padded. */
1585 #endif
1587 /* Update ARGS_SIZE, the total stack space for args so far. */
1593 /* Increment ARGS_SO_FAR, which has info about which arg-registers
1594 have been used, etc. */
1598 }
1599 }
1601 /* Update ARGS_SIZE to contain the total size for the argument block.
1602 Return the original constant component of the argument block's size.
1604 REG_PARM_STACK_SPACE holds the number of bytes of stack space reserved
1605 for arguments passed in registers. */
1607 static int
1610 tree fndecl ATTRIBUTE_UNUSED,
1611 tree fntype ATTRIBUTE_UNUSED,
1613 {
1616 /* For accumulate outgoing args mode we don't need to align, since the frame
1617 will be already aligned. Align to STACK_BOUNDARY in order to prevent
1618 backends from generating misaligned frame sizes. */
1622 /* Compute the actual size of the argument block required. The variable
1623 and constant sizes must be combined, the size may have to be rounded,
1624 and there may be a minimum required size. */
1627 {
1633 {
1634 /* We don't handle this case yet. To handle it correctly we have
1635 to add the delta, round and subtract the delta.
1636 Currently no machine description requires this support. */
1639 }
1642 {
1643 args_size->var
1647 /* The area corresponding to register parameters is not to count in
1648 the size of the block we need. So make the adjustment. */
1650 args_size->var
1653 }
1654 }
1655 else
1656 {
1661 + stack_pointer_delta
1663 / preferred_stack_boundary
1668 reg_parm_stack_space);
1672 }
1674 }
1676 /* Precompute parameters as needed for a function call.
1678 FLAGS is mask of ECF_* constants.
1680 NUM_ACTUALS is the number of arguments.
1682 ARGS is an array containing information for each argument; this
1683 routine fills in the INITIAL_VALUE and VALUE fields for each
1684 precomputed argument. */
1686 static void
1688 {
1691 /* If this is a libcall, then precompute all arguments so that we do not
1692 get extraneous instructions emitted as part of the libcall sequence. */
1694 /* If we preallocated the stack space, and some arguments must be passed
1695 on the stack, then we must precompute any parameter which contains a
1696 function call which will store arguments on the stack.
1697 Otherwise, evaluating the parameter may clobber previous parameters
1698 which have already been stored into the stack. (we have code to avoid
1699 such case by saving the outgoing stack arguments, but it results in
1700 worse code) */
1705 {
1706 tree type;
1707 machine_mode mode;
1712 /* If this is an addressable type, we cannot pre-evaluate it. */
1721 {
1727 /* CSE will replace this only if it contains args[i].value
1728 pseudo, so convert it down to the declared mode using
1729 a SUBREG. */
1733 {
1738 }
1739 }
1740 }
1741 }
1743 /* Given the current state of MUST_PREALLOCATE and information about
1744 arguments to a function call in NUM_ACTUALS, ARGS and ARGS_SIZE,
1745 compute and return the final value for MUST_PREALLOCATE. */
1747 static int
1750 {
1751 /* See if we have or want to preallocate stack space.
1753 If we would have to push a partially-in-regs parm
1754 before other stack parms, preallocate stack space instead.
1756 If the size of some parm is not a multiple of the required stack
1757 alignment, we must preallocate.
1759 If the total size of arguments that would otherwise create a copy in
1760 a temporary (such as a CALL) is more than half the total argument list
1761 size, preallocation is faster.
1763 Another reason to preallocate is if we have a machine (like the m88k)
1764 where stack alignment is required to be maintained between every
1765 pair of insns, not just when the call is made. However, we assume here
1766 that such machines either do not have push insns (and hence preallocation
1767 would occur anyway) or the problem is taken care of with
1768 PUSH_ROUNDING. */
1771 {
1777 {
1782 /* We preallocate in case there are bounds passed
1783 in the bounds table to have precomputed address
1784 for bounds association. */
1794 copy_to_evaluate_size
1796 }
1801 }
1803 }
1805 /* If we preallocated stack space, compute the address of each argument
1806 and store it into the ARGS array.
1808 We need not ensure it is a valid memory address here; it will be
1809 validized when it is used.
1811 ARGBLOCK is an rtx for the address of the outgoing arguments. */
1813 static void
1815 {
1817 {
1825 {
1828 rtx addr;
1833 /* Skip this parm if it will not be passed on the stack. */
1839 /* Pointer Bounds are never passed on the stack. */
1845 else
1851 {
1852 /* Only part of the parameter is being passed on the stack.
1853 Generate a simple memory reference of the correct size. */
1859 }
1860 else
1861 {
1865 }
1871 {
1874 }
1879 else
1885 {
1886 /* Only part of the parameter is being passed on the stack.
1887 Generate a simple memory reference of the correct size.
1888 */
1891 }
1892 else
1893 {
1897 }
1900 /* Function incoming arguments may overlap with sibling call
1901 outgoing arguments and we cannot allow reordering of reads
1902 from function arguments with stores to outgoing arguments
1903 of sibling calls. */
1906 }
1907 }
1908 }
1910 /* Given a FNDECL and EXP, return an rtx suitable for use as a target address
1911 in a call instruction.
1913 FNDECL is the tree node for the target function. For an indirect call
1914 FNDECL will be NULL_TREE.
1916 ADDR is the operand 0 of CALL_EXPR for this call. */
1918 static rtx
1920 {
1921 rtx funexp;
1923 /* Get the function to call, in the form of RTL. */
1925 {
1929 /* Get a SYMBOL_REF rtx for the function address. */
1931 }
1932 else
1933 /* Generate an rtx (probably a pseudo-register) for the address. */
1934 {
1938 }
1940 }
1942 /* Internal state for internal_arg_pointer_based_exp and its helpers. */
1943 static struct
1944 {
1945 /* Last insn that has been scanned by internal_arg_pointer_based_exp_scan,
1946 or NULL_RTX if none has been scanned yet. */
1948 /* Vector indexed by REGNO - FIRST_PSEUDO_REGISTER, recording if a pseudo is
1949 based on crtl->args.internal_arg_pointer. The element is NULL_RTX if the
1950 pseudo isn't based on it, a CONST_INT offset if the pseudo is based on it
1951 with fixed offset, or PC if this is with variable or unknown offset. */
1957 /* Helper function for internal_arg_pointer_based_exp. Scan insns in
1958 the tail call sequence, starting with first insn that hasn't been
1959 scanned yet, and note for each pseudo on the LHS whether it is based
1960 on crtl->args.internal_arg_pointer or not, and what offset from that
1961 that pointer it has. */
1963 static void
1965 {
1970 else
1974 {
1977 {
1980 /* Punt on pseudos set multiple times. */
1985 else
1988 {
1990 internal_arg_pointer_exp_state.cache
1993 }
1994 }
1998 }
2001 }
2003 /* Compute whether RTL is based on crtl->args.internal_arg_pointer. Return
2004 NULL_RTX if RTL isn't based on it, a CONST_INT offset if RTL is based on
2005 it with fixed offset, or PC if this is with variable or unknown offset.
2006 TOPLEVEL is true if the function is invoked at the topmost level. */
2008 static rtx
2010 {
2021 {
2026 }
2028 /* When called at the topmost level, scan pseudo assignments in between the
2029 last scanned instruction in the tail call sequence and the latest insn
2030 in that sequence. */
2035 {
2041 }
2045 {
2051 }
2054 }
2056 /* Return true if and only if SIZE storage units (usually bytes)
2057 starting from address ADDR overlap with already clobbered argument
2058 area. This function is used to determine if we should give up a
2059 sibcall. */
2061 static bool
2063 {
2064 HOST_WIDE_INT i;
2065 rtx val;
2074 else
2079 else
2087 {
2094 }
2097 }
2099 /* Do the register loads required for any wholly-register parms or any
2100 parms which are passed both on the stack and in a register. Their
2101 expressions were already evaluated.
2103 Mark all register-parms as living through the call, putting these USE
2104 insns in the CALL_INSN_FUNCTION_USAGE field.
2106 When IS_SIBCALL, perform the check_sibcall_argument_overlap
2107 checking, setting *SIBCALL_FAILURE if appropriate. */
2109 static void
2113 {
2117 {
2121 {
2126 /* Set non-negative if we must move a word at a time, even if
2127 just one word (e.g, partial == 4 && mode == DFmode). Set
2128 to -1 if we just use a normal move insn. This value can be
2129 zero if the argument is a zero size structure. */
2132 ;
2134 {
2137 }
2139 {
2142 }
2143 else
2146 /* Handle calls that pass values in multiple non-contiguous
2147 locations. The Irix 6 ABI has examples of this. */
2152 /* If simple case, just do move. If normal partial, store_one_arg
2153 has already loaded the register for us. In all other cases,
2154 load the register(s) from memory. */
2157 {
2159 #ifdef BLOCK_REG_PADDING
2160 /* Handle case where we have a value that needs shifting
2161 up to the msb. eg. a QImode value and we're padding
2162 upward on a BYTES_BIG_ENDIAN machine. */
2166 {
2167 rtx x;
2170 /* Assigning REG here rather than a temp makes CALL_FUSAGE
2171 report the whole reg as used. Strictly speaking, the
2172 call only uses SIZE bytes at the msb end, but it doesn't
2173 seem worth generating rtl to say that. */
2178 }
2179 #endif
2180 }
2182 /* If we have pre-computed the values to put in the registers in
2183 the case of non-aligned structures, copy them in now. */
2191 {
2194 /* Check for overlap with already clobbered argument area,
2195 providing that this has non-zero size. */
2198 && (mem_overlaps_already_clobbered_arg_p
2205 else
2206 {
2220 }
2222 /* Handle a BLKmode that needs shifting. */
2224 #ifdef BLOCK_REG_PADDING
2226 #else
2227 && BYTES_BIG_ENDIAN
2228 #endif
2229 )
2230 {
2235 rtx x;
2240 }
2241 }
2243 /* When a parameter is a block, and perhaps in other cases, it is
2244 possible that it did a load from an argument slot that was
2245 already clobbered. */
2250 /* Handle calls that pass values in multiple non-contiguous
2251 locations. The Irix 6 ABI has examples of this. */
2259 }
2260 }
2261 }
2263 /* We need to pop PENDING_STACK_ADJUST bytes. But, if the arguments
2264 wouldn't fill up an even multiple of PREFERRED_UNIT_STACK_BOUNDARY
2265 bytes, then we would need to push some additional bytes to pad the
2266 arguments. So, we compute an adjust to the stack pointer for an
2267 amount that will leave the stack under-aligned by UNADJUSTED_ARGS_SIZE
2268 bytes. Then, when the arguments are pushed the stack will be perfectly
2269 aligned. ARGS_SIZE->CONSTANT is set to the number of bytes that should
2270 be popped after the call. Returns the adjustment. */
2272 static int
2276 {
2277 /* The number of bytes to pop so that the stack will be
2278 under-aligned by UNADJUSTED_ARGS_SIZE bytes. */
2279 HOST_WIDE_INT adjustment;
2280 /* The alignment of the stack after the arguments are pushed, if we
2281 just pushed the arguments without adjust the stack here. */
2284 unadjusted_alignment
2288 /* We want to get rid of as many of the PENDING_STACK_ADJUST bytes
2289 as possible -- leaving just enough left to cancel out the
2290 UNADJUSTED_ALIGNMENT. In other words, we want to ensure that the
2291 PENDING_STACK_ADJUST is non-negative, and congruent to
2292 -UNADJUSTED_ALIGNMENT modulo the PREFERRED_UNIT_STACK_BOUNDARY. */
2294 /* Begin by trying to pop all the bytes. */
2295 unadjusted_alignment
2296 = (unadjusted_alignment
2299 /* Push enough additional bytes that the stack will be aligned
2300 after the arguments are pushed. */
2302 {
2305 else
2307 }
2309 /* Now, sets ARGS_SIZE->CONSTANT so that we pop the right number of
2310 bytes after the call. The right number is the entire
2311 PENDING_STACK_ADJUST less our ADJUSTMENT plus the amount required
2312 by the arguments in the first place. */
2313 args_size->constant
2317 }
2319 /* Scan X expression if it does not dereference any argument slots
2320 we already clobbered by tail call arguments (as noted in stored_args_map
2321 bitmap).
2322 Return nonzero if X expression dereferences such argument slots,
2323 zero otherwise. */
2325 static int
2327 {
2328 RTX_CODE code;
2337 /* We need not check the operands of the CALL expression itself. */
2345 /* Scan all subexpressions. */
2348 {
2350 {
2353 }
2355 {
2359 }
2360 }
2362 }
2364 /* Scan sequence after INSN if it does not dereference any argument slots
2365 we already clobbered by tail call arguments (as noted in stored_args_map
2366 bitmap). If MARK_STORED_ARGS_MAP, add stack slots for ARG to
2367 stored_args_map bitmap afterwards (when ARG is a register MARK_STORED_ARGS_MAP
2368 should be 0). Return nonzero if sequence after INSN dereferences such argument
2369 slots, zero otherwise. */
2371 static int
2374 {
2379 else
2388 {
2391 else
2396 }
2398 }
2400 /* Given that a function returns a value of mode MODE at the most
2401 significant end of hard register VALUE, shift VALUE left or right
2402 as specified by LEFT_P. Return true if some action was needed. */
2404 bool
2406 {
2407 HOST_WIDE_INT shift;
2414 /* Use ashr rather than lshr for right shifts. This is for the benefit
2415 of the MIPS port, which requires SImode values to be sign-extended
2416 when stored in 64-bit registers. */
2421 }
2423 /* If X is a likely-spilled register value, copy it to a pseudo
2424 register and return that register. Return X otherwise. */
2426 static rtx
2428 {
2429 rtx new_rtx;
2434 {
2435 /* Make sure that we generate a REG rather than a CONCAT.
2436 Moves into CONCATs can need nontrivial instructions,
2437 and the whole point of this function is to avoid
2438 using the hard register directly in such a situation. */
2444 }
2446 }
2448 /* Helper function for expand_call.
2449 Return false is EXP is not implementable as a sibling call. */
2451 static bool
2453 rtx structure_value_addr,
2454 tree funtype,
2456 tree fndecl,
2458 tree addr,
2460 {
2462 {
2463 maybe_complain_about_tail_call
2465 "machine description does not have"
2468 }
2470 /* Doing sibling call optimization needs some work, since
2471 structure_value_addr can be allocated on the stack.
2472 It does not seem worth the effort since few optimizable
2473 sibling calls will return a structure. */
2475 {
2478 }
2480 #ifdef REG_PARM_STACK_SPACE
2481 /* If outgoing reg parm stack space changes, we can not do sibcall. */
2485 {
2487 "inconsistent size of stack space"
2488 " allocated for arguments which are"
2491 }
2492 #endif
2494 /* Check whether the target is able to optimize the call
2495 into a sibcall. */
2497 {
2499 "target is not able to optimize the"
2502 }
2504 /* Functions that do not return exactly once may not be sibcall
2505 optimized. */
2507 {
2510 }
2512 {
2515 }
2518 {
2521 }
2523 /* If the called function is nested in the current one, it might access
2524 some of the caller's arguments, but could clobber them beforehand if
2525 the argument areas are shared. */
2527 {
2530 }
2532 /* If this function requires more stack slots than the current
2533 function, we cannot change it into a sibling call.
2534 crtl->args.pretend_args_size is not part of the
2535 stack allocated by our caller. */
2537 {
2539 "callee required more stack slots"
2542 }
2544 /* If the callee pops its own arguments, then it must pop exactly
2545 the same number of arguments as the current function. */
2550 {
2552 "inconsistent number of"
2555 }
2558 {
2562 }
2564 /* All checks passed. */
2566 }
2568 /* Generate all the code for a CALL_EXPR exp
2569 and return an rtx for its value.
2570 Store the value in TARGET (specified as an rtx) if convenient.
2571 If the value is stored in TARGET then TARGET is returned.
2572 If IGNORE is nonzero, then we ignore the value of the function call. */
2574 rtx
2576 {
2577 /* Nonzero if we are currently expanding a call. */
2580 /* RTX for the function to be called. */
2581 rtx funexp;
2582 /* Sequence of insns to perform a normal "call". */
2584 /* Sequence of insns to perform a tail "call". */
2586 /* Data type of the function. */
2587 tree funtype;
2588 tree type_arg_types;
2589 tree rettype;
2590 /* Declaration of the function being called,
2591 or 0 if the function is computed (not known by name). */
2593 /* The type of the function being called. */
2594 tree fntype;
2599 /* Register in which non-BLKmode value will be returned,
2600 or 0 if no value or if value is BLKmode. */
2601 rtx valreg;
2602 /* Register(s) in which bounds are returned. */
2604 /* Address where we should return a BLKmode value;
2605 0 if value not BLKmode. */
2607 /* Nonzero if that address is being passed by treating it as
2608 an extra, implicit first parameter. Otherwise,
2609 it is passed by being copied directly into struct_value_rtx. */
2611 /* Holds the value of implicit argument for the struct value. */
2613 /* Size of aggregate value wanted, or zero if none wanted
2614 or if we are using the non-reentrant PCC calling convention
2615 or expecting the value in registers. */
2617 /* Nonzero if called function returns an aggregate in memory PCC style,
2618 by returning the address of where to find it. */
2622 /* Number of actual parameters in this call, including struct value addr. */
2624 /* Number of named args. Args after this are anonymous ones
2625 and they must all go on the stack. */
2627 /* Number of complex actual arguments that need to be split. */
2630 /* Vector of information about each argument.
2631 Arguments are numbered in the order they will be pushed,
2632 not the order they are written. */
2635 /* Total size in bytes of all the stack-parms scanned so far. */
2638 /* Size of arguments before any adjustments (such as rounding). */
2640 /* Data on reg parms scanned so far. */
2641 CUMULATIVE_ARGS args_so_far_v;
2642 cumulative_args_t args_so_far;
2643 /* Nonzero if a reg parm has been scanned. */
2645 /* Nonzero if this is an indirect function call. */
2647 /* Nonzero if we must avoid push-insns in the args for this call.
2648 If stack space is allocated for register parameters, but not by the
2649 caller, then it is preallocated in the fixed part of the stack frame.
2650 So the entire argument block must then be preallocated (i.e., we
2651 ignore PUSH_ROUNDING in that case). */
2655 /* Size of the stack reserved for parameter registers. */
2658 /* Address of space preallocated for stack parms
2659 (on machines that lack push insns), or 0 if space not preallocated. */
2662 /* Mask of ECF_ and ERF_ flags. */
2665 #ifdef REG_PARM_STACK_SPACE
2666 /* Define the boundary of the register parm stack space that needs to be
2667 saved, if any. */
2670 #endif
2678 /* State variables to track stack modifications. */
2684 /* Some stack pointer alterations we make are performed via
2685 allocate_dynamic_stack_space. This modifies the stack_pointer_delta,
2686 which we then also need to save/restore along the way. */
2689 rtx call_fusage;
2692 /* The alignment of the stack, in bits. */
2694 /* The alignment of the stack, in bytes. */
2696 /* The static chain value to use for this call. */
2697 rtx static_chain_value;
2698 /* See if this is "nothrow" function call. */
2702 /* See if we can find a DECL-node for the actual function, and get the
2703 function attributes (flags) from the function decl or type node. */
2706 {
2710 }
2711 else
2712 {
2717 }
2722 /* Warn if this value is an aggregate type,
2723 regardless of which calling convention we are using for it. */
2727 /* If the result of a non looping pure or const function call is
2728 ignored (or void), and none of its arguments are volatile, we can
2729 avoid expanding the call and just evaluate the arguments for
2730 side-effects. */
2735 {
2737 tree arg;
2738 call_expr_arg_iterator iter;
2742 {
2745 }
2748 {
2752 }
2753 }
2755 #ifdef REG_PARM_STACK_SPACE
2757 #endif
2763 /* Set up a place to return a structure. */
2765 /* Cater to broken compilers. */
2767 {
2768 /* This call returns a big structure. */
2771 #ifdef PCC_STATIC_STRUCT_RETURN
2772 {
2774 }
2776 {
2779 /* Even if it is semantically safe to use the target as the return
2780 slot, it may be not sufficiently aligned for the return type. */
2782 && target
2788 else
2789 {
2790 /* For variable-sized objects, we must be called with a target
2791 specified. If we were to allocate space on the stack here,
2792 we would have no way of knowing when to free it. */
2796 }
2797 }
2799 }
2801 /* Figure out the amount to which the stack should be aligned. */
2804 {
2806 /* Without automatic stack alignment, we can't increase preferred
2807 stack boundary. With automatic stack alignment, it is
2808 unnecessary since unless we can guarantee that all callers will
2809 align the outgoing stack properly, callee has to align its
2810 stack anyway. */
2815 }
2817 /* Operand 0 is a pointer-to-function; get the type of the function. */
2822 /* Count whether there are actual complex arguments that need to be split
2823 into their real and imaginary parts. Munge the type_arg_types
2824 appropriately here as well. */
2826 {
2827 call_expr_arg_iterator iter;
2828 tree arg;
2830 {
2834 num_complex_actuals++;
2835 }
2837 }
2838 else
2844 /* If struct_value_rtx is 0, it means pass the address
2845 as if it were an extra parameter. Put the argument expression
2846 in structure_value_addr_value. */
2848 {
2849 /* If structure_value_addr is a REG other than
2850 virtual_outgoing_args_rtx, we can use always use it. If it
2851 is not a REG, we must always copy it into a register.
2852 If it is virtual_outgoing_args_rtx, we must copy it to another
2853 register in some cases. */
2855 || (ACCUMULATE_OUTGOING_ARGS
2856 && stack_arg_under_construction
2862 structure_value_addr_value =
2865 }
2867 /* Count the arguments and set NUM_ACTUALS. */
2868 num_actuals =
2871 /* Compute number of named args.
2872 First, do a raw count of the args for INIT_CUMULATIVE_ARGS. */
2875 n_named_args
2877 /* Count the struct value address, if it is passed as a parm. */
2879 else
2880 /* If we know nothing, treat all args as named. */
2883 /* Start updating where the next arg would go.
2885 On some machines (such as the PA) indirect calls have a different
2886 calling convention than normal calls. The fourth argument in
2887 INIT_CUMULATIVE_ARGS tells the backend if this is an indirect call
2888 or not. */
2892 /* Now possibly adjust the number of named args.
2893 Normally, don't include the last named arg if anonymous args follow.
2894 We do include the last named arg if
2895 targetm.calls.strict_argument_naming() returns nonzero.
2896 (If no anonymous args follow, the result of list_length is actually
2897 one too large. This is harmless.)
2899 If targetm.calls.pretend_outgoing_varargs_named() returns
2900 nonzero, and targetm.calls.strict_argument_naming() returns zero,
2901 this machine will be able to place unnamed args that were passed
2902 in registers into the stack. So treat all args as named. This
2903 allows the insns emitting for a specific argument list to be
2904 independent of the function declaration.
2906 If targetm.calls.pretend_outgoing_varargs_named() returns zero,
2907 we do not have any reliable way to pass unnamed args in
2908 registers, so we must force them into memory. */
2912 ;
2915 /* Don't include the last named arg. */
2917 else
2918 /* Treat all args as named. */
2921 /* Make a vector to hold all the information about each arg. */
2925 /* Build up entries in the ARGS array, compute the size of the
2926 arguments into ARGS_SIZE, etc. */
2938 /* Now make final decision about preallocating stack space. */
2943 /* If the structure value address will reference the stack pointer, we
2944 must stabilize it. We don't need to do this if we know that we are
2945 not going to adjust the stack pointer in processing this call. */
2950 structure_value_addr))
2955 /* Tail calls can make things harder to debug, and we've traditionally
2956 pushed these optimizations into -O2. Don't try if we're already
2957 expanding a call, as that means we're an argument. Don't try if
2958 there's cleanups, as we know there's code to follow the call. */
2961 || !flag_optimize_sibling_calls
2966 /* If the user has marked the function as requiring tail-call
2967 optimization, attempt it. */
2971 /* Rest of purposes for tail call optimizations to fail. */
2974 structure_value_addr,
2975 funtype,
2976 reg_parm_stack_space,
2977 fndecl,
2980 /* Check if caller and callee disagree in promotion of function
2981 return value. */
2983 {
2993 caller_promoted_mode
2997 callee_promoted_mode
3008 {
3011 "caller and callee disagree in"
3012 " promotion of function"
3014 }
3015 }
3017 /* Ensure current function's preferred stack boundary is at least
3018 what we need. Stack alignment may also increase preferred stack
3019 boundary. */
3022 else
3027 /* We want to make two insn chains; one for a sibling call, the other
3028 for a normal call. We will select one of the two chains after
3029 initial RTL generation is complete. */
3031 {
3033 /* We want to emit any pending stack adjustments before the tail
3034 recursion "call". That way we know any adjustment after the tail
3035 recursion call can be ignored if we indeed use the tail
3036 call expansion. */
3037 saved_pending_stack_adjust save;
3039 rtx next_arg_reg;
3042 {
3043 /* State variables we need to save and restore between
3044 iterations. */
3046 }
3049 else
3052 /* Other state variables that we must reinitialize each time
3053 through the loop (that are not initialized by the loop itself). */
3057 /* Start a new sequence for the normal call case.
3059 From this point on, if the sibling call fails, we want to set
3060 sibcall_failure instead of continuing the loop. */
3063 /* Don't let pending stack adjusts add up to too much.
3064 Also, do all pending adjustments now if there is any chance
3065 this might be a call to alloca or if we are expanding a sibling
3066 call sequence.
3067 Also do the adjustments before a throwing call, otherwise
3068 exception handling can fail; PR 19225. */
3077 /* Precompute any arguments as needed. */
3081 /* Now we are about to start emitting insns that can be deleted
3082 if a libcall is deleted. */
3092 /* Compute the actual size of the argument block required. The variable
3093 and constant sizes must be combined, the size may have to be rounded,
3094 and there may be a minimum required size. When generating a sibcall
3095 pattern, do not round up, since we'll be re-using whatever space our
3096 caller provided. */
3097 unadjusted_args_size
3106 /* The argument block when performing a sibling call is the
3107 incoming argument block. */
3109 {
3112 argblock
3114 else
3115 argblock
3120 }
3122 /* If we have no actual push instructions, or shouldn't use them,
3123 make space for all args right now. */
3125 {
3127 {
3132 /* stack_arg_under_construction says whether a stack arg is
3133 being constructed at the old stack level. Pushing the stack
3134 gets a clean outgoing argument block. */
3137 }
3141 }
3142 else
3143 {
3144 /* Note that we must go through the motions of allocating an argument
3145 block even if the size is zero because we may be storing args
3146 in the area reserved for register arguments, which may be part of
3147 the stack frame. */
3151 /* Store the maximum argument space used. It will be pushed by
3152 the prologue (if ACCUMULATE_OUTGOING_ARGS, or stack overflow
3153 checking). */
3159 {
3161 {
3162 /* Since the stack pointer will never be pushed, it is
3163 possible for the evaluation of a parm to clobber
3164 something we have already written to the stack.
3165 Since most function calls on RISC machines do not use
3166 the stack, this is uncommon, but must work correctly.
3168 Therefore, we save any area of the stack that was already
3169 written and that we are using. Here we set up to do this
3170 by making a new stack usage map from the old one. The
3171 actual save will be done by store_one_arg.
3173 Another approach might be to try to reorder the argument
3174 evaluations to avoid this conflicting stack usage. */
3176 /* Since we will be writing into the entire argument area,
3177 the map must be allocated for its entire size, not just
3178 the part that is the responsibility of the caller. */
3183 highest_outgoing_arg_in_use
3185 else
3186 highest_outgoing_arg_in_use
3195 initial_highest_arg_in_use);
3199 (highest_outgoing_arg_in_use
3203 /* The address of the outgoing argument list must not be
3204 copied to a register here, because argblock would be left
3205 pointing to the wrong place after the call to
3206 allocate_dynamic_stack_space below. */
3209 }
3210 else
3211 {
3213 {
3214 /* Try to reuse some or all of the pending_stack_adjust
3215 to get this space. */
3216 needed
3217 = (combine_pending_stack_adjustment_and_call
3220 preferred_unit_stack_boundary));
3222 /* combine_pending_stack_adjustment_and_call computes
3223 an adjustment before the arguments are allocated.
3224 Account for them and see whether or not the stack
3225 needs to go up or down. */
3229 {
3230 /* We're releasing stack space. */
3231 /* ??? We can avoid any adjustment at all if we're
3232 already aligned. FIXME. */
3236 }
3237 else
3238 /* We need to allocate space. We'll do that in
3239 push_block below. */
3241 }
3243 /* Special case this because overhead of `push_block' in
3244 this case is non-trivial. */
3247 else
3248 {
3252 }
3254 /* We only really need to call `copy_to_reg' in the case
3255 where push insns are going to be used to pass ARGBLOCK
3256 to a function call in ARGS. In that case, the stack
3257 pointer changes value from the allocation point to the
3258 call point, and hence the value of
3259 VIRTUAL_OUTGOING_ARGS_RTX changes as well. But might
3260 as well always do it. */
3262 }
3263 }
3264 }
3267 {
3268 /* The save/restore code in store_one_arg handles all
3269 cases except one: a constructor call (including a C
3270 function returning a BLKmode struct) to initialize
3271 an argument. */
3273 {
3274 rtx push_size
3280 {
3285 /* stack_arg_under_construction says whether a stack
3286 arg is being constructed at the old stack level.
3287 Pushing the stack gets a clean outgoing argument
3288 block. */
3289 old_stack_arg_under_construction
3292 /* Make a new map for the new argument list. */
3297 }
3298 /* We can pass TRUE as the 4th argument because we just
3299 saved the stack pointer and will restore it right after
3300 the call. */
3303 }
3305 /* If argument evaluation might modify the stack pointer,
3306 copy the address of the argument list to a register. */
3309 {
3312 }
3313 }
3317 /* Stack is properly aligned, pops can't safely be deferred during
3318 the evaluation of the arguments. */
3319 NO_DEFER_POP;
3321 /* Precompute all register parameters. It isn't safe to compute
3322 anything once we have started filling any specific hard regs.
3323 TLS symbols sometimes need a call to resolve. Precompute
3324 register parameters before any stack pointer manipulation
3325 to avoid unaligned stack in the called function. */
3328 OK_DEFER_POP;
3330 /* Perform stack alignment before the first push (the last arg). */
3334 {
3335 /* When the stack adjustment is pending, we get better code
3336 by combining the adjustments. */
3339 {
3340 pending_stack_adjust
3341 = (combine_pending_stack_adjustment_and_call
3344 preferred_unit_stack_boundary));
3346 }
3350 }
3351 /* Now that the stack is properly aligned, pops can't safely
3352 be deferred during the evaluation of the arguments. */
3353 NO_DEFER_POP;
3355 /* Record the maximum pushed stack space size. We need to delay
3356 doing it this far to take into account the optimization done
3357 by combine_pending_stack_adjustment_and_call. */
3359 && !ACCUMULATE_OUTGOING_ARGS
3360 && pass
3362 {
3366 }
3372 else
3375 #ifdef REG_PARM_STACK_SPACE
3376 /* Save the fixed argument area if it's part of the caller's frame and
3377 is clobbered by argument setup for this call. */
3381 #endif
3383 /* Now store (and compute if necessary) all non-register parms.
3384 These come before register parms, since they can require block-moves,
3385 which could clobber the registers used for register parms.
3386 Parms which have partial registers are not stored here,
3387 but we do preallocate space here if they want that. */
3390 {
3391 /* Delay bounds until all other args are stored. */
3395 {
3398 /* We don't allow passing huge (> 2^30 B) arguments
3399 by value. It would cause an overflow later on. */
3402 {
3405 }
3409 reg_parm_stack_space)
3414 }
3417 call_fusage
3420 call_fusage);
3421 }
3423 /* If we have a parm that is passed in registers but not in memory
3424 and whose alignment does not permit a direct copy into registers,
3425 make a group of pseudos that correspond to each register that we
3426 will later fill. */
3430 /* Now store any partially-in-registers parm.
3431 This is the last place a block-move can happen. */
3435 {
3438 /* On targets with weird calling conventions (e.g. PA) it's
3439 hard to ensure that all cases of argument overlap between
3440 stack and registers work. Play it safe and bail out. */
3442 {
3445 }
3449 reg_parm_stack_space)
3454 }
3459 {
3462 }
3466 /* Figure out the register where the value, if any, will come back. */
3471 {
3473 {
3480 }
3481 else
3482 {
3487 fndecl,
3489 }
3491 /* If VALREG is a PARALLEL whose first member has a zero
3492 offset, use that. This is for targets such as m68k that
3493 return the same value in multiple places. */
3495 {
3502 }
3503 }
3505 /* Store all bounds not passed in registers. */
3507 {
3512 ? NULL
3514 }
3516 /* If register arguments require space on the stack and stack space
3517 was not preallocated, allocate stack space here for arguments
3518 passed in registers. */
3520 && !ACCUMULATE_OUTGOING_ARGS
3524 /* Pass the function the address in which to return a
3525 structure value. */
3527 {
3528 structure_value_addr
3533 NULL_RTX)));
3537 }
3547 /* Save a pointer to the last insn before the call, so that we can
3548 later safely search backwards to find the CALL_INSN. */
3551 /* Set up next argument register. For sibling calls on machines
3552 with register windows this should be the incoming register. */
3555 VOIDmode,
3556 void_type_node,
3558 else
3564 {
3570 && valreg
3573 call_fusage
3576 call_fusage);
3577 }
3578 /* All arguments and registers used for the call must be set up by
3579 now! */
3581 /* Stack must be properly aligned now. */
3585 /* Generate the actual call instruction. */
3592 {
3596 {
3600 }
3603 }
3605 /* If the call setup or the call itself overlaps with anything
3606 of the argument setup we probably clobbered our call address.
3607 In that case we can't do sibcalls. */
3612 /* If a non-BLKmode value is returned at the most significant end
3613 of a register, shift the register right by the appropriate amount
3614 and update VALREG accordingly. BLKmode values are handled by the
3615 group load/store machinery below. */
3617 && !pcc_struct_value
3622 {
3626 }
3629 {
3633 /* The return value from a malloc-like function is a pointer. */
3639 /* The return value from a malloc-like function can not alias
3640 anything else. */
3644 /* Write out the sequence. */
3649 }
3651 /* For calls to `setjmp', etc., inform
3652 function.c:setjmp_warnings that it should complain if
3653 nonvolatile values are live. For functions that cannot
3654 return, inform flow that control does not fall through. */
3657 {
3658 /* The barrier must be emitted
3659 immediately after the CALL_INSN. Some ports emit more
3660 than just a CALL_INSN above, so we must search for it here. */
3664 {
3666 /* There was no CALL_INSN? */
3668 }
3672 /* Stack adjustments after a noreturn call are dead code.
3673 However when NO_DEFER_POP is in effect, we must preserve
3674 stack_pointer_delta. */
3676 {
3679 }
3680 }
3682 /* If value type not void, return an rtx for the value. */
3688 {
3690 {
3691 target
3694 structure_value_addr));
3696 }
3697 }
3699 {
3700 /* This is the special C++ case where we need to
3701 know what the true target was. We take care to
3702 never use this value more than once in one expression. */
3706 }
3707 /* Handle calls that return values in multiple non-contiguous locations.
3708 The Irix 6 ABI has examples of this. */
3710 {
3714 ;
3716 /* Handle the result of a emit_group_move_into_temps
3717 call in the previous pass. */
3719 else
3722 }
3726 {
3729 /* We have to copy a return value in a CLASS_LIKELY_SPILLED hard
3730 reg to a plain register. */
3734 /* If TARGET is a MEM in the argument area, and we have
3735 saved part of the argument area, then we can't store
3736 directly into TARGET as it may get overwritten when we
3737 restore the argument save area below. Don't work too
3738 hard though and simply force TARGET to a register if it
3739 is a MEM; the optimizer is quite likely to sort it out. */
3743 {
3746 }
3750 else
3751 {
3752 /* TARGET and VALREG cannot be equal at this point
3753 because the latter would not have
3754 REG_FUNCTION_VALUE_P true, while the former would if
3755 it were referring to the same register.
3757 If they refer to the same register, this move will be
3758 a no-op, except when function inlining is being
3759 done. */
3762 /* If we are setting a MEM, this code must be executed.
3763 Since it is emitted after the call insn, sibcall
3764 optimization cannot be performed in that case. */
3767 }
3768 }
3769 else
3772 /* If we promoted this return value, make the proper SUBREG.
3773 TARGET might be const0_rtx here, so be careful. */
3777 {
3781 machine_mode pmode;
3783 /* Ensure we promote as expected, and get the new unsignedness. */
3791 {
3798 }
3803 }
3805 /* If size of args is variable or this was a constructor call for a stack
3806 argument, restore saved stack-pointer value. */
3809 {
3823 }
3825 {
3826 #ifdef REG_PARM_STACK_SPACE
3830 #endif
3832 /* If we saved any argument areas, restore them. */
3835 {
3837 rtx stack_area
3844 else
3847 BLOCK_OP_CALL_PARM);
3848 }
3852 }
3854 /* If this was alloca, record the new stack level. */
3858 /* Free up storage we no longer need. */
3868 {
3871 /* Restore the pending stack adjustment now that we have
3872 finished generating the sibling call sequence. */
3876 /* Prepare arg structure for next iteration. */
3878 {
3882 }
3887 }
3888 else
3889 {
3892 /* Verify that we've deallocated all the stack we used. */
3894 || (old_stack_allocated
3896 }
3898 /* If something prevents making this a sibling call,
3899 zero out the sequence. */
3902 else
3904 }
3906 /* If tail call production succeeded, we need to remove REG_EQUIV notes on
3907 arguments too, as argument area is now clobbered by the call. */
3909 {
3912 }
3913 else
3914 {
3917 /* Ideally we'd emit a message for all of the ways that it could
3918 have failed. */
3920 }
3922 currently_expanding_call--;
3926 /* Join result with returned bounds so caller may use them if needed. */
3930 }
3932 /* A sibling call sequence invalidates any REG_EQUIV notes made for
3933 this function's incoming arguments.
3935 At the start of RTL generation we know the only REG_EQUIV notes
3936 in the rtl chain are those for incoming arguments, so we can look
3937 for REG_EQUIV notes between the start of the function and the
3938 NOTE_INSN_FUNCTION_BEG.
3940 This is (slight) overkill. We could keep track of the highest
3941 argument we clobber and be more selective in removing notes, but it
3942 does not seem to be worth the effort. */
3944 void
3946 {
3950 {
3951 rtx note;
3953 /* There are never REG_EQUIV notes for the incoming arguments
3954 after the NOTE_INSN_FUNCTION_BEG note, so stop if we see it. */
3964 }
3965 }
3967 /* Traverse a list of TYPES and expand all complex types into their
3968 components. */
3969 static tree
3971 {
3972 tree p;
3974 /* Before allocating memory, check for the common case of no complex. */
3976 {
3981 }
3984 found:
3988 {
3993 {
3996 /* Rewrite complex type with component type. */
4000 /* Add another component type for the imaginary part. */
4005 /* Skip the newly created node. */
4007 }
4008 }
4011 }
4012 \f
4013 /* Output a library call to function FUN (a SYMBOL_REF rtx).
4014 The RETVAL parameter specifies whether return value needs to be saved, other
4015 parameters are documented in the emit_library_call function below. */
4017 static rtx
4021 {
4022 /* Total size in bytes of all the stack-parms scanned so far. */
4024 /* Size of arguments before any adjustments (such as rounding). */
4027 rtx fun;
4028 /* Todo, choose the correct decl type of orgfun. Sadly this information
4029 isn't present here, so we default to native calling abi here. */
4034 CUMULATIVE_ARGS args_so_far_v;
4035 cumulative_args_t args_so_far;
4036 struct arg
4037 {
4038 rtx value;
4039 machine_mode mode;
4040 rtx reg;
4043 rtx save_area;
4044 };
4049 rtx valreg;
4059 #ifdef REG_PARM_STACK_SPACE
4060 /* Define the boundary of the register parm stack space that needs to be
4061 save, if any. */
4064 #endif
4066 /* Size of the stack reserved for parameter registers. */
4073 #ifdef REG_PARM_STACK_SPACE
4075 #endif
4077 /* By default, library functions cannot throw. */
4081 {
4099 }
4102 /* Ensure current function's preferred stack boundary is at least
4103 what we need. */
4107 /* If this kind of value comes back in memory,
4108 decide where in memory it should come back. */
4110 {
4113 {
4114 #ifdef PCC_STATIC_STRUCT_RETURN
4115 rtx pointer_reg
4125 else
4127 #endif
4128 /* This call returns a big structure. */
4130 }
4131 }
4132 else
4135 /* ??? Unfinished: must pass the memory address as an argument. */
4137 /* Copy all the libcall-arguments out of the varargs data
4138 and into a vector ARGVEC.
4140 Compute how to pass each argument. We only support a very small subset
4141 of the full argument passing conventions to limit complexity here since
4142 library functions shouldn't have many args. */
4147 #ifdef INIT_CUMULATIVE_LIBCALL_ARGS
4149 #else
4151 #endif
4161 /* If there's a structure value address to be passed,
4162 either pass it in the special place, or pass it as an extra argument. */
4164 {
4167 nargs++;
4169 /* Make sure it is a reasonable operand for a move or push insn. */
4185 #ifdef STACK_PARMS_IN_REG_PARM_AREA
4187 #else
4189 #endif
4199 count++;
4200 }
4203 {
4208 /* We cannot convert the arg value to the mode the library wants here;
4209 must do it earlier where we know the signedness of the arg. */
4213 /* Make sure it is a reasonable operand for a move or push insn. */
4219 {
4220 rtx slot;
4221 int must_copy
4224 /* If this was a CONST function, it is now PURE since it now
4225 reads memory. */
4227 {
4230 }
4233 {
4238 }
4239 else
4240 {
4244 }
4248 call_fusage);
4252 slot),
4253 call_fusage);
4257 }
4271 {
4273 #ifdef STACK_PARMS_IN_REG_PARM_AREA
4275 #else
4277 #endif
4282 }
4283 #ifdef BLOCK_REG_PADDING
4284 else
4285 /* The argument is passed entirely in registers. See at which
4286 end it should be padded. */
4290 #endif
4293 }
4295 /* If this machine requires an external definition for library
4296 functions, write one out. */
4301 + stack_pointer_delta
4303 / STACK_BYTES
4308 reg_parm_stack_space);
4317 {
4321 }
4324 {
4325 /* Since the stack pointer will never be pushed, it is possible for
4326 the evaluation of a parm to clobber something we have already
4327 written to the stack. Since most function calls on RISC machines
4328 do not use the stack, this is uncommon, but must work correctly.
4330 Therefore, we save any area of the stack that was already written
4331 and that we are using. Here we set up to do this by making a new
4332 stack usage map from the old one.
4334 Another approach might be to try to reorder the argument
4335 evaluations to avoid this conflicting stack usage. */
4339 /* Since we will be writing into the entire argument area, the
4340 map must be allocated for its entire size, not just the part that
4341 is the responsibility of the caller. */
4348 else
4356 initial_highest_arg_in_use);
4363 /* We must be careful to use virtual regs before they're instantiated,
4364 and real regs afterwards. Loop optimization, for example, can create
4365 new libcalls after we've instantiated the virtual regs, and if we
4366 use virtuals anyway, they won't match the rtl patterns. */
4370 STACK_POINTER_OFFSET);
4371 else
4373 }
4374 else
4375 {
4378 }
4380 /* We push args individually in reverse order, perform stack alignment
4381 before the first push (the last arg). */
4388 #ifdef REG_PARM_STACK_SPACE
4390 {
4391 /* The argument list is the property of the called routine and it
4392 may clobber it. If the fixed area has been used for previous
4393 parameters, we must save and restore it. */
4396 }
4397 #endif
4399 /* When expanding a normal call, args are stored in push order,
4400 which is the reverse of what we have here. */
4404 {
4407 }
4411 /* Push the args that need to be pushed. */
4415 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
4416 are to be pushed. */
4418 {
4427 {
4428 rtx use;
4431 {
4432 /* If this is being stored into a pre-allocated, fixed-size,
4433 stack area, save any previous data at that location. */
4436 {
4437 /* stack_slot is negative, but we want to index stack_usage_map
4438 with positive values. */
4441 }
4442 else
4443 {
4446 }
4449 /* Don't worry about things in the fixed argument area;
4450 it has already been saved. */
4454 i++;
4457 {
4458 /* We need to make a save area. */
4459 unsigned int size
4461 machine_mode save_mode
4463 rtx adr
4466 rtx stack_area
4470 {
4474 );
4478 stack_area,
4480 BLOCK_OP_CALL_PARM);
4481 }
4482 else
4483 {
4487 }
4488 }
4489 }
4494 reg_parm_stack_space,
4497 /* Now mark the segment we just used. */
4502 NO_DEFER_POP;
4504 /* Indicate argument access so that alias.c knows that these
4505 values are live. */
4511 else
4512 {
4513 /* When arguments are pushed, trying to tell alias.c where
4514 exactly this argument is won't work, because the
4515 auto-increment causes confusion. So we merely indicate
4516 that we access something with a known mode somewhere on
4517 the stack. */
4521 }
4525 }
4526 }
4532 /* Now load any reg parms into their regs. */
4534 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
4535 are to be pushed. */
4537 {
4542 #ifdef BLOCK_REG_PADDING
4544 #endif
4546 /* Handle calls that pass values in multiple non-contiguous
4547 locations. The PA64 has examples of this for library calls. */
4551 {
4553 #ifdef BLOCK_REG_PADDING
4556 /* Copied from load_register_parameters. */
4558 /* Handle case where we have a value that needs shifting
4559 up to the msb. eg. a QImode value and we're padding
4560 upward on a BYTES_BIG_ENDIAN machine. */
4564 {
4565 rtx x;
4568 /* Assigning REG here rather than a temp makes CALL_FUSAGE
4569 report the whole reg as used. Strictly speaking, the
4570 call only uses SIZE bytes at the msb end, but it doesn't
4571 seem worth generating rtl to say that. */
4576 }
4577 #endif
4578 }
4580 NO_DEFER_POP;
4581 }
4583 /* Any regs containing parms remain in use through the call. */
4585 {
4590 {
4593 {
4598 }
4599 else
4601 }
4602 }
4604 /* Pass the function the address in which to return a structure value. */
4606 {
4610 NULL_RTX)));
4613 }
4615 /* Don't allow popping to be deferred, since then
4616 cse'ing of library calls could delete a call and leave the pop. */
4617 NO_DEFER_POP;
4621 /* Stack must be properly aligned now. */
4627 /* We pass the old value of inhibit_defer_pop + 1 to emit_call_1, which
4628 will set inhibit_defer_pop to that value. */
4629 /* The return type is needed to decide how many bytes the function pops.
4630 Signedness plays no role in that, so for simplicity, we pretend it's
4631 always signed. We also assume that the list of arguments passed has
4632 no impact, so we pretend it is unknown. */
4638 struct_value_size,
4641 valreg,
4645 {
4650 }
4652 /* Right-shift returned value if necessary. */
4656 {
4659 }
4663 /* For calls to `setjmp', etc., inform function.c:setjmp_warnings
4664 that it should complain if nonvolatile values are live. For
4665 functions that cannot return, inform flow that control does not
4666 fall through. */
4668 {
4669 /* The barrier note must be emitted
4670 immediately after the CALL_INSN. Some ports emit more than
4671 just a CALL_INSN above, so we must search for it here. */
4674 {
4676 /* There was no CALL_INSN? */
4678 }
4681 }
4683 /* Consider that "regular" libcalls, i.e. all of them except for LCT_THROW
4684 and LCT_RETURNS_TWICE, cannot perform non-local gotos. */
4686 {
4689 {
4691 /* There was no CALL_INSN? */
4693 }
4696 }
4698 /* Now restore inhibit_defer_pop to its actual original value. */
4699 OK_DEFER_POP;
4703 /* Copy the value to the right place. */
4705 {
4707 {
4712 }
4714 {
4718 }
4719 else
4720 {
4721 /* Convert to the proper mode if a promotion has been active. */
4723 {
4730 }
4734 else
4736 }
4737 }
4740 {
4741 #ifdef REG_PARM_STACK_SPACE
4745 #endif
4747 /* If we saved any argument areas, restore them. */
4750 {
4759 validize_mem
4762 BLOCK_OP_CALL_PARM);
4763 else
4765 }
4769 }
4775 }
4776 \f
4777 /* Output a library call to function FUN (a SYMBOL_REF rtx)
4778 (emitting the queue unless NO_QUEUE is nonzero),
4779 for a value of mode OUTMODE,
4780 with NARGS different arguments, passed as alternating rtx values
4781 and machine_modes to convert them to.
4783 FN_TYPE should be LCT_NORMAL for `normal' calls, LCT_CONST for
4784 `const' calls, LCT_PURE for `pure' calls, or other LCT_ value for
4785 other types of library calls. */
4787 void
4790 {
4796 }
4797 \f
4798 /* Like emit_library_call except that an extra argument, VALUE,
4799 comes second and says where to store the result.
4800 (If VALUE is zero, this function chooses a convenient way
4801 to return the value.
4803 This function returns an rtx for where the value is to be found.
4804 If VALUE is nonzero, VALUE is returned. */
4806 rtx
4810 {
4811 rtx result;
4820 }
4821 \f
4823 /* Store pointer bounds argument ARG into Bounds Table entry
4824 associated with PARM. */
4825 static void
4827 {
4830 /* We may pass bounds not associated with any pointer. */
4832 {
4836 }
4837 /* Find pointer associated with bounds and where it is
4838 passed. */
4839 else
4840 {
4842 {
4846 }
4848 {
4856 else
4857 {
4860 }
4861 }
4862 else
4863 {
4872 else
4874 }
4875 }
4877 /* Expand bounds. */
4882 }
4884 /* Store a single argument for a function call
4885 into the register or memory area where it must be passed.
4886 *ARG describes the argument value and where to pass it.
4888 ARGBLOCK is the address of the stack-block for all the arguments,
4889 or 0 on a machine where arguments are pushed individually.
4891 MAY_BE_ALLOCA nonzero says this could be a call to `alloca'
4892 so must be careful about how the stack is used.
4894 VARIABLE_SIZE nonzero says that this was a variable-sized outgoing
4895 argument stack. This is used if ACCUMULATE_OUTGOING_ARGS to indicate
4896 that we need not worry about saving and restoring the stack.
4898 FNDECL is the declaration of the function we are calling.
4900 Return nonzero if this arg should cause sibcall failure,
4901 zero otherwise. */
4903 static int
4906 {
4917 /* Push a new temporary level for any temporaries we make for
4918 this argument. */
4922 {
4923 /* If this is being stored into a pre-allocated, fixed-size, stack area,
4924 save any previous data at that location. */
4926 {
4928 {
4929 /* stack_slot is negative, but we want to index stack_usage_map
4930 with positive values. */
4933 else
4937 }
4938 else
4939 {
4942 else
4946 }
4949 /* Don't worry about things in the fixed argument area;
4950 it has already been saved. */
4954 i++;
4957 {
4958 /* We need to make a save area. */
4965 {
4966 arg->save_area
4970 stack_area,
4972 BLOCK_OP_CALL_PARM);
4973 }
4974 else
4975 {
4978 }
4979 }
4980 }
4981 }
4983 /* If this isn't going to be placed on both the stack and in registers,
4984 set up the register and number of words. */
4986 {
4989 else
4992 }
4994 /* Being passed entirely in a register. We shouldn't be called in
4995 this case. */
4998 /* If this arg needs special alignment, don't load the registers
4999 here. */
5003 /* If this is being passed partially in a register, we can't evaluate
5004 it directly into its stack slot. Otherwise, we can. */
5006 {
5007 /* stack_arg_under_construction is nonzero if a function argument is
5008 being evaluated directly into the outgoing argument list and
5009 expand_call must take special action to preserve the argument list
5010 if it is called recursively.
5012 For scalar function arguments stack_usage_map is sufficient to
5013 determine which stack slots must be saved and restored. Scalar
5014 arguments in general have pass_on_stack == 0.
5016 If this argument is initialized by a function which takes the
5017 address of the argument (a C++ constructor or a C function
5018 returning a BLKmode structure), then stack_usage_map is
5019 insufficient and expand_call must push the stack around the
5020 function call. Such arguments have pass_on_stack == 1.
5022 Note that it is always safe to set stack_arg_under_construction,
5023 but this generates suboptimal code if set when not needed. */
5026 stack_arg_under_construction++;
5029 (partial
5034 /* If we are promoting object (or for any other reason) the mode
5035 doesn't agree, convert the mode. */
5042 stack_arg_under_construction--;
5043 }
5045 /* Check for overlap with already clobbered argument area. */
5052 /* Don't allow anything left on stack from computation
5053 of argument to alloca. */
5058 /* If the value is already in the stack slot, we are done. */
5059 ;
5061 {
5065 /* Argument is a scalar, not entirely passed in registers.
5066 (If part is passed in registers, arg->partial says how much
5067 and emit_push_insn will take care of putting it there.)
5069 Push it, and if its size is less than the
5070 amount of space allocated to it,
5071 also bump stack pointer by the additional space.
5072 Note that in C the default argument promotions
5073 will prevent such mismatches. */
5076 /* Compute how much space the push instruction will push.
5077 On many machines, pushing a byte will advance the stack
5078 pointer by a halfword. */
5079 #ifdef PUSH_ROUNDING
5081 #endif
5084 /* Compute how much space the argument should get:
5085 round up to a multiple of the alignment for arguments. */
5091 /* Compute the alignment of the pushed argument. */
5094 {
5097 {
5100 }
5101 }
5103 /* This isn't already where we want it on the stack, so put it there.
5104 This can either be done with push or copy insns. */
5111 /* Unless this is a partially-in-register argument, the argument is now
5112 in the stack. */
5115 }
5116 else
5117 {
5118 /* BLKmode, at least partly to be pushed. */
5122 rtx size_rtx;
5124 /* Pushing a nonscalar.
5125 If part is passed in registers, PARTIAL says how much
5126 and emit_push_insn will take care of putting it there. */
5128 /* Round its size up to a multiple
5129 of the allocation unit for arguments. */
5132 {
5135 }
5136 else
5137 {
5138 /* PUSH_ROUNDING has no effect on us, because emit_push_insn
5139 for BLKmode is careful to avoid it. */
5145 EXPAND_NORMAL);
5146 }
5150 /* When an argument is padded down, the block is aligned to
5151 PARM_BOUNDARY, but the actual argument isn't. */
5153 {
5157 {
5160 }
5161 }
5164 {
5165 /* emit_push_insn might not work properly if arg->value and
5166 argblock + arg->locate.offset areas overlap. */
5175 {
5179 /* arg.locate doesn't contain the pretend_args_size offset,
5180 it's part of argblock. Ensure we don't count it in I. */
5183 else
5186 /* expand_call should ensure this. */
5192 {
5195 }
5197 {
5198 /* Use arg->locate.size.constant instead of size_rtx
5199 because we only care about the part of the argument
5200 on the stack. */
5204 }
5205 else
5206 {
5207 /* Even though they appear to be at the same location,
5208 if part of the outgoing argument is in registers,
5209 they aren't really at the same location. Check for
5210 this by making sure that the incoming size is the
5211 same as the outgoing size. */
5214 }
5215 }
5216 }
5223 /* Unless this is a partially-in-register argument, the argument is now
5224 in the stack.
5226 ??? Unlike the case above, in which we want the actual
5227 address of the data, so that we can load it directly into a
5228 register, here we want the address of the stack slot, so that
5229 it's properly aligned for word-by-word copying or something
5230 like that. It's not clear that this is always correct. */
5233 }
5236 {
5238 arg->parallel_value
5241 }
5243 /* Mark all slots this store used. */
5249 /* Once we have pushed something, pops can't safely
5250 be deferred during the rest of the arguments. */
5251 NO_DEFER_POP;
5253 /* Free any temporary slots made in processing this argument. */
5257 }
5259 /* Nonzero if we do not know how to pass TYPE solely in registers. */
5261 bool
5263 const_tree type)
5264 {
5268 /* If the type has variable size... */
5272 /* If the type is marked as addressable (it is required
5273 to be constructed into the stack)... */
5278 }
5280 /* Another version of the TARGET_MUST_PASS_IN_STACK hook. This one
5281 takes trailing padding of a structure into account. */
5282 /* ??? Should be able to merge these two by examining BLOCK_REG_PADDING. */
5284 bool
5286 {
5290 /* If the type has variable size... */
5294 /* If the type is marked as addressable (it is required
5295 to be constructed into the stack)... */
5299 /* If the padding and mode of the type is such that a copy into
5300 a register would put it into the wrong part of the register. */
5308 }