| blob | 86369e9cfdc832a13599172a3b7f02827dce09c7 |
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/>. */
53 /* Like PREFERRED_STACK_BOUNDARY but in units of bytes, not bits. */
54 #define STACK_BYTES (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT)
56 /* Data structure and subroutines used within expand_call. */
58 struct arg_data
59 {
60 /* Tree node for this argument. */
61 tree tree_value;
62 /* Mode for value; TYPE_MODE unless promoted. */
63 machine_mode mode;
64 /* Current RTL value for argument, or 0 if it isn't precomputed. */
65 rtx value;
66 /* Initially-compute RTL value for argument; only for const functions. */
67 rtx initial_value;
68 /* Register to pass this argument in, 0 if passed on stack, or an
69 PARALLEL if the arg is to be copied into multiple non-contiguous
70 registers. */
71 rtx reg;
72 /* Register to pass this argument in when generating tail call sequence.
73 This is not the same register as for normal calls on machines with
74 register windows. */
75 rtx tail_call_reg;
76 /* If REG is a PARALLEL, this is a copy of VALUE pulled into the correct
77 form for emit_group_move. */
78 rtx parallel_value;
79 /* If value is passed in neither reg nor stack, this field holds a number
80 of a special slot to be used. */
81 rtx special_slot;
82 /* For pointer bounds hold an index of parm bounds are bound to. -1 if
83 there is no such pointer. */
85 /* If pointer_arg refers a structure, then pointer_offset holds an offset
86 of a pointer in this structure. */
88 /* If REG was promoted from the actual mode of the argument expression,
89 indicates whether the promotion is sign- or zero-extended. */
91 /* Number of bytes to put in registers. 0 means put the whole arg
92 in registers. Also 0 if not passed in registers. */
94 /* Nonzero if argument must be passed on stack.
95 Note that some arguments may be passed on the stack
96 even though pass_on_stack is zero, just because FUNCTION_ARG says so.
97 pass_on_stack identifies arguments that *cannot* go in registers. */
99 /* Some fields packaged up for locate_and_pad_parm. */
101 /* Location on the stack at which parameter should be stored. The store
102 has already been done if STACK == VALUE. */
103 rtx stack;
104 /* Location on the stack of the start of this argument slot. This can
105 differ from STACK if this arg pads downward. This location is known
106 to be aligned to TARGET_FUNCTION_ARG_BOUNDARY. */
107 rtx stack_slot;
108 /* Place that this stack area has been saved, if needed. */
109 rtx save_area;
110 /* If an argument's alignment does not permit direct copying into registers,
111 copy in smaller-sized pieces into pseudos. These are stored in a
112 block pointed to by this field. The next field says how many
113 word-sized pseudos we made. */
116 };
118 /* A vector of one char per byte of stack space. A byte if nonzero if
119 the corresponding stack location has been used.
120 This vector is used to prevent a function call within an argument from
121 clobbering any stack already set up. */
124 /* Size of STACK_USAGE_MAP. */
127 /* A bitmap of virtual-incoming stack space. Bit is set if the corresponding
128 stack location's tail call argument has been already stored into the stack.
129 This bitmap is used to prevent sibling call optimization if function tries
130 to use parent's incoming argument slots when they have been already
131 overwritten with tail call arguments. */
134 /* stack_arg_under_construction is nonzero when an argument may be
135 initialized with a constructor call (including a C function that
136 returns a BLKmode struct) and expand_call must take special action
137 to make sure the object being constructed does not overlap the
138 argument list for the constructor call. */
143 cumulative_args_t);
172 #ifdef REG_PARM_STACK_SPACE
175 #endif
176 \f
177 /* Force FUNEXP into a form suitable for the address of a CALL,
178 and return that as an rtx. Also load the static chain register
179 if FNDECL is a nested function.
181 CALL_FUSAGE points to a variable holding the prospective
182 CALL_INSN_FUNCTION_USAGE information. */
184 rtx
187 {
188 /* Make a valid memory address and copy constants through pseudo-regs,
189 but not for a constant address if -fno-function-cse. */
191 /* If we are using registers for parameters, force the
192 function address into a register now. */
193 funexp = ((reg_parm_seen
197 else
198 {
199 /* funexp could be a SYMBOL_REF represents a function pointer which is
200 of ptr_mode. In this case, it should be converted into address mode
201 to be a valid address for memory rtx pattern. See PR 64971. */
206 {
209 }
210 }
215 {
216 rtx chain;
224 }
227 }
229 /* Generate instructions to call function FUNEXP,
230 and optionally pop the results.
231 The CALL_INSN is the first insn generated.
233 FNDECL is the declaration node of the function. This is given to the
234 hook TARGET_RETURN_POPS_ARGS to determine whether this function pops
235 its own args.
237 FUNTYPE is the data type of the function. This is given to the hook
238 TARGET_RETURN_POPS_ARGS to determine whether this function pops its
239 own args. We used to allow an identifier for library functions, but
240 that doesn't work when the return type is an aggregate type and the
241 calling convention says that the pointer to this aggregate is to be
242 popped by the callee.
244 STACK_SIZE is the number of bytes of arguments on the stack,
245 ROUNDED_STACK_SIZE is that number rounded up to
246 PREFERRED_STACK_BOUNDARY; zero if the size is variable. This is
247 both to put into the call insn and to generate explicit popping
248 code if necessary.
250 STRUCT_VALUE_SIZE is the number of bytes wanted in a structure value.
251 It is zero if this call doesn't want a structure value.
253 NEXT_ARG_REG is the rtx that results from executing
254 targetm.calls.function_arg (&args_so_far, VOIDmode, void_type_node, true)
255 just after all the args have had their registers assigned.
256 This could be whatever you like, but normally it is the first
257 arg-register beyond those used for args in this call,
258 or 0 if all the arg-registers are used in this call.
259 It is passed on to `gen_call' so you can put this info in the call insn.
261 VALREG is a hard register in which a value is returned,
262 or 0 if the call does not return a value.
264 OLD_INHIBIT_DEFER_POP is the value that `inhibit_defer_pop' had before
265 the args to this call were processed.
266 We restore `inhibit_defer_pop' to that value.
268 CALL_FUSAGE is either empty or an EXPR_LIST of USE expressions that
269 denote registers used by the called function. */
271 static void
273 tree funtype ATTRIBUTE_UNUSED,
274 HOST_WIDE_INT stack_size ATTRIBUTE_UNUSED,
275 HOST_WIDE_INT rounded_stack_size,
276 HOST_WIDE_INT struct_value_size ATTRIBUTE_UNUSED,
279 cumulative_args_t args_so_far ATTRIBUTE_UNUSED)
280 {
286 /* Sibling call patterns never pop arguments (no sibcall(_value)_pop
287 patterns exist). Any popping that the callee does on return will
288 be from our caller's frame rather than ours. */
290 {
293 #ifdef CALL_POPS_ARGS
295 #endif
296 }
298 /* Ensure address is valid. SYMBOL_REF is already valid, so no need,
299 and we don't want to load it into a register as an optimization,
300 because prepare_call_address already did it if it should be done. */
306 {
309 /* Although a built-in FUNCTION_DECL and its non-__builtin
310 counterpart compare equal and get a shared mem_attrs, they
311 produce different dump output in compare-debug compilations,
312 if an entry gets garbage collected in one compilation, then
313 adds a different (but equivalent) entry, while the other
314 doesn't run the garbage collector at the same spot and then
315 shares the mem_attr with the equivalent entry. */
317 {
321 }
324 }
329 {
332 rounded_stack_size_rtx,
334 else
337 }
338 /* If the target has "call" or "call_value" insns, then prefer them
339 if no arguments are actually popped. If the target does not have
340 "call" or "call_value" insns, then we must use the popping versions
341 even if the call has no arguments to pop. */
343 || !(valreg
346 {
349 /* If this subroutine pops its own args, record that in the call insn
350 if possible, for the sake of frame pointer elimination. */
354 rounded_stack_size_rtx,
356 else
361 }
362 else
363 {
367 else
370 }
373 /* Find the call we just emitted. */
376 /* Some target create a fresh MEM instead of reusing the one provided
377 above. Set its MEM_EXPR. */
384 /* Mark instrumented calls. */
388 /* Put the register usage information there. */
391 /* If this is a const call, then set the insn's unchanging bit. */
395 /* If this is a pure call, then set the insn's unchanging bit. */
399 /* If this is a const call, then set the insn's unchanging bit. */
403 /* Create a nothrow REG_EH_REGION note, if needed. */
410 {
413 }
417 /* Restore this now, so that we do defer pops for this call's args
418 if the context of the call as a whole permits. */
422 {
434 /* If popup is needed, stack realign must use DRAP */
437 }
438 /* For noreturn calls when not accumulating outgoing args force
439 REG_ARGS_SIZE note to prevent crossjumping of calls with different
440 args sizes. */
445 {
446 /* If returning from the subroutine does not automatically pop the args,
447 we need an instruction to pop them sooner or later.
448 Perhaps do it now; perhaps just record how much space to pop later.
450 If returning from the subroutine does pop the args, indicate that the
451 stack pointer will be changed. */
454 {
456 /* Just pretend we did the pop. */
461 else
463 }
464 }
465 /* When we accumulate outgoing args, we must avoid any stack manipulations.
466 Restore the stack pointer to its original value now. Usually
467 ACCUMULATE_OUTGOING_ARGS targets don't get here, but there are exceptions.
468 On i386 ACCUMULATE_OUTGOING_ARGS can be enabled on demand, and
469 popping variants of functions exist as well.
471 ??? We may optimize similar to defer_pop above, but it is
472 probably not worthwhile.
474 ??? It will be worthwhile to enable combine_stack_adjustments even for
475 such machines. */
478 }
480 /* Determine if the function identified by FNDECL is one with
481 special properties we wish to know about. Modify FLAGS accordingly.
483 For example, if the function might return more than one time (setjmp), then
484 set ECF_RETURNS_TWICE.
486 Set ECF_MAY_BE_ALLOCA for any memory allocation function that might allocate
487 space from the stack such as alloca. */
489 static int
491 {
494 /* For instrumentation clones we want to derive flags
495 from the original name. */
502 /* Exclude functions not at the file scope, or not `extern',
503 since they are not the magic functions we would otherwise
504 think they are.
505 FIXME: this should be handled with attributes, not with this
506 hacky imitation of DECL_ASSEMBLER_NAME. It's (also) wrong
507 because you can declare fork() inside a function if you
508 wish. */
512 {
516 /* We assume that alloca will always be called by name. It
517 makes no sense to pass it as a pointer-to-function to
518 anything that does not understand its behavior. */
524 /* Disregard prefix _ or __. */
526 {
529 else
531 }
533 /* ECF_RETURNS_TWICE is safe even for -ffreestanding. */
540 }
544 {
551 }
554 }
556 /* Similar to special_function_p; return a set of ERF_ flags for the
557 function FNDECL. */
558 static int
560 {
561 tree attr;
575 {
588 }
589 }
591 /* Return nonzero when FNDECL represents a call to setjmp. */
593 int
595 {
599 }
602 /* Return true if STMT may be an alloca call. */
604 bool
606 {
607 tree fndecl;
617 }
619 /* Return true if STMT is a builtin alloca call. */
621 bool
623 {
624 tree fndecl;
632 {
638 }
641 }
643 /* Return true when exp contains a builtin alloca call. */
645 bool
647 {
648 tree fndecl;
653 {
659 }
662 }
664 /* Return TRUE if FNDECL is either a TM builtin or a TM cloned
665 function. Return FALSE otherwise. */
667 static bool
669 {
677 {
679 {
722 }
723 }
725 }
727 /* Detect flags (function attributes) from the function decl or type node. */
729 int
731 {
735 {
736 /* The function exp may have the `malloc' attribute. */
740 /* The function exp may have the `returns_twice' attribute. */
744 /* Process the pure and const attributes. */
761 {
768 }
771 }
773 {
781 }
782 else
786 {
790 }
793 }
795 /* Detect flags from a CALL_EXPR. */
797 int
799 {
807 else
808 {
812 else
814 }
817 }
819 /* Return true if TYPE should be passed by invisible reference. */
821 bool
824 {
826 {
827 /* If this type contains non-trivial constructors, then it is
828 forbidden for the middle-end to create any new copies. */
832 /* GCC post 3.4 passes *all* variable sized types by reference. */
836 /* If a record type should be passed the same as its first (and only)
837 member, use the type and mode of that member. */
839 {
842 }
843 }
847 }
849 /* Return true if TYPE, which is passed by reference, should be callee
850 copied instead of caller copied. */
852 bool
855 {
859 named_arg);
860 }
863 /* Precompute all register parameters as described by ARGS, storing values
864 into fields within the ARGS array.
866 NUM_ACTUALS indicates the total number elements in the ARGS array.
868 Set REG_PARM_SEEN if we encounter a register parameter. */
870 static void
873 {
880 {
884 {
889 }
891 /* If we are to promote the function arg to a wider mode,
892 do it now. */
900 /* If the value is a non-legitimate constant, force it into a
901 pseudo now. TLS symbols sometimes need a call to resolve. */
906 /* If we're going to have to load the value by parts, pull the
907 parts into pseudos. The part extraction process can involve
908 non-trivial computation. */
910 {
915 }
917 /* If the value is expensive, and we are inside an appropriately
918 short loop, put the value into a pseudo and then put the pseudo
919 into the hard reg.
921 For small register classes, also do this if this call uses
922 register parameters. This is to avoid reload conflicts while
923 loading the parameters registers. */
932 && ((*reg_parm_seen
936 }
937 }
939 #ifdef REG_PARM_STACK_SPACE
941 /* The argument list is the property of the called routine and it
942 may clobber it. If the fixed area has been used for previous
943 parameters, we must save and restore it. */
945 static rtx
946 save_fixed_argument_area (int reg_parm_stack_space, rtx argblock, int *low_to_save, int *high_to_save)
947 {
951 /* Compute the boundary of the area that needs to be saved, if any. */
961 {
963 machine_mode save_mode;
965 rtx addr;
966 rtx stack_area;
967 rtx save_area;
970 ;
978 /* If we don't have the required alignment, must do this
979 in BLKmode. */
986 else
994 {
998 }
999 else
1000 {
1003 }
1006 }
1009 }
1011 static void
1013 {
1020 else
1029 else
1032 BLOCK_OP_CALL_PARM);
1033 }
1036 /* If any elements in ARGS refer to parameters that are to be passed in
1037 registers, but not in memory, and whose alignment does not permit a
1038 direct copy into registers. Copy the values into a group of pseudos
1039 which we will later copy into the appropriate hard registers.
1041 Pseudos for each unaligned argument will be stored into the array
1042 args[argnum].aligned_regs. The caller is responsible for deallocating
1043 the aligned_regs array if it is nonzero. */
1045 static void
1047 {
1057 {
1062 {
1065 }
1066 else
1067 {
1070 }
1074 /* Structures smaller than a word are normally aligned to the
1075 least significant byte. On a BYTES_BIG_ENDIAN machine,
1076 this means we must skip the empty high order bytes when
1077 calculating the bit offset. */
1079 #ifdef BLOCK_REG_PADDING
1083 #else
1084 && BYTES_BIG_ENDIAN
1085 #endif
1086 )
1090 {
1099 /* There is no need to restrict this code to loading items
1100 in TYPE_ALIGN sized hunks. The bitfield instructions can
1101 load up entire word sized registers efficiently.
1103 ??? This may not be needed anymore.
1104 We use to emit a clobber here but that doesn't let later
1105 passes optimize the instructions we emit. By storing 0 into
1106 the register later passes know the first AND to zero out the
1107 bitfield being set in the register is unnecessary. The store
1108 of 0 will be deleted as will at least the first AND. */
1115 }
1116 }
1117 }
1119 /* Issue an error if CALL_EXPR was flagged as requiring
1120 tall-call optimization. */
1122 static void
1124 {
1130 }
1132 /* Fill in ARGS_SIZE and ARGS array based on the parameters found in
1133 CALL_EXPR EXP.
1135 NUM_ACTUALS is the total number of parameters.
1137 N_NAMED_ARGS is the total number of named arguments.
1139 STRUCT_VALUE_ADDR_VALUE is the implicit argument for a struct return
1140 value, or null.
1142 FNDECL is the tree code for the target of this call (if known)
1144 ARGS_SO_FAR holds state needed by the target to know where to place
1145 the next argument.
1147 REG_PARM_STACK_SPACE is the number of bytes of stack space reserved
1148 for arguments which are passed in registers.
1150 OLD_STACK_LEVEL is a pointer to an rtx which olds the old stack level
1151 and may be modified by this routine.
1153 OLD_PENDING_ADJ, MUST_PREALLOCATE and FLAGS are pointers to integer
1154 flags which may be modified by this routine.
1156 MAY_TAILCALL is cleared if we encounter an invisible pass-by-reference
1157 that requires allocation of stack space.
1159 CALL_FROM_THUNK_P is true if this call is the jump from a thunk to
1160 the thunked-to function. */
1162 static void
1169 cumulative_args_t args_so_far,
1174 {
1178 /* Count arg position in order args appear. */
1188 /* In this loop, we consider args in the order they are written.
1189 We fill up ARGS from the back. */
1192 {
1194 call_expr_arg_iterator iter;
1195 tree arg;
1199 {
1201 j--;
1203 /* If we pass structure address then we need to
1204 create bounds for it. Since created bounds is
1205 a call statement, we expand it right here to avoid
1206 fixing all other places where it may be expanded. */
1208 {
1215 j--;
1216 }
1217 }
1220 {
1223 /* Remember last param with pointer and associate it
1224 with following pointer bounds. */
1227 {
1232 {
1235 }
1236 }
1240 {
1244 }
1246 {
1247 /* We expect bounds in instrumented calls only.
1248 Otherwise it is a sign we lost flag due to some optimization
1249 and may emit call args incorrectly. */
1252 /* For structures look for the next available pointer. */
1254 {
1261 /* Check we have no more pointers in the structure. */
1264 }
1267 /* Check we covered all pointers in the previous
1268 non bounds arg. */
1271 }
1272 else
1276 && argtype
1279 {
1282 j--;
1284 }
1285 else
1287 j--;
1288 argpos++;
1289 }
1293 }
1297 /* I counts args in order (to be) pushed; ARGPOS counts in order written. */
1299 {
1302 machine_mode mode;
1304 /* Replace erroneous argument with constant zero. */
1308 /* If TYPE is a transparent union or record, pass things the way
1309 we would pass the first field of the union or record. We have
1310 already verified that the modes are the same. */
1315 /* Decide where to pass this arg.
1317 args[i].reg is nonzero if all or part is passed in registers.
1319 args[i].partial is nonzero if part but not all is passed in registers,
1320 and the exact value says how many bytes are passed in registers.
1322 args[i].pass_on_stack is nonzero if the argument must at least be
1323 computed on the stack. It may then be loaded back into registers
1324 if args[i].reg is nonzero.
1326 These decisions are driven by the FUNCTION_... macros and must agree
1327 with those made by function.c. */
1329 /* See if this argument should be passed by invisible reference. */
1332 {
1336 callee_copies
1340 /* If we're compiling a thunk, pass through invisible references
1341 instead of making a copy. */
1343 || (callee_copies
1348 {
1349 /* We may have turned the parameter value into an SSA name.
1350 Go back to the original parameter so we can take the
1351 address. */
1353 {
1357 }
1358 /* Argument setup code may have copied the value to register. We
1359 revert that optimization now because the tail call code must
1360 use the original location. */
1370 /* We can't use sibcalls if a callee-copied argument is
1371 stored in the current function's frame. */
1373 {
1376 "a callee-copied argument is"
1377 " stored in the current "
1379 }
1387 }
1388 else
1389 {
1390 /* We make a copy of the object and pass the address to the
1391 function being called. */
1392 rtx copy;
1399 {
1400 /* This is a variable-sized object. Make space on the stack
1401 for it. */
1405 {
1409 }
1411 /* We can pass TRUE as the 4th argument because we just
1412 saved the stack pointer and will restore it right after
1413 the call. */
1420 }
1421 else
1426 /* Just change the const function to pure and then let
1427 the next test clear the pure based on
1428 callee_copies. */
1430 {
1433 }
1443 "argument must be passed"
1445 }
1446 }
1459 {
1462 }
1464 /* If this is a sibling call and the machine has register windows, the
1465 register window has to be unwinded before calling the routine, so
1466 arguments have to go into the incoming registers. */
1471 else
1481 /* If FUNCTION_ARG returned a (parallel [(expr_list (nil) ...) ...]),
1482 it means that we are to pass this arg in the register(s) designated
1483 by the PARALLEL, but also to pass it in the stack. */
1488 /* If this is an addressable type, we must preallocate the stack
1489 since we must evaluate the object into its final location.
1491 If this is to be passed in both registers and the stack, it is simpler
1492 to preallocate. */
1497 /* No stack allocation and padding for bounds. */
1499 ;
1500 /* Compute the stack-size of this argument. */
1505 #ifdef STACK_PARMS_IN_REG_PARM_AREA
1507 #else
1509 #endif
1510 reg_parm_stack_space,
1513 #ifdef BLOCK_REG_PADDING
1514 else
1515 /* The argument is passed entirely in registers. See at which
1516 end it should be padded. */
1520 #endif
1522 /* Update ARGS_SIZE, the total stack space for args so far. */
1528 /* Increment ARGS_SO_FAR, which has info about which arg-registers
1529 have been used, etc. */
1533 }
1534 }
1536 /* Update ARGS_SIZE to contain the total size for the argument block.
1537 Return the original constant component of the argument block's size.
1539 REG_PARM_STACK_SPACE holds the number of bytes of stack space reserved
1540 for arguments passed in registers. */
1542 static int
1545 tree fndecl ATTRIBUTE_UNUSED,
1546 tree fntype ATTRIBUTE_UNUSED,
1548 {
1551 /* For accumulate outgoing args mode we don't need to align, since the frame
1552 will be already aligned. Align to STACK_BOUNDARY in order to prevent
1553 backends from generating misaligned frame sizes. */
1557 /* Compute the actual size of the argument block required. The variable
1558 and constant sizes must be combined, the size may have to be rounded,
1559 and there may be a minimum required size. */
1562 {
1568 {
1569 /* We don't handle this case yet. To handle it correctly we have
1570 to add the delta, round and subtract the delta.
1571 Currently no machine description requires this support. */
1574 }
1577 {
1578 args_size->var
1582 /* The area corresponding to register parameters is not to count in
1583 the size of the block we need. So make the adjustment. */
1585 args_size->var
1588 }
1589 }
1590 else
1591 {
1596 + stack_pointer_delta
1598 / preferred_stack_boundary
1603 reg_parm_stack_space);
1607 }
1609 }
1611 /* Precompute parameters as needed for a function call.
1613 FLAGS is mask of ECF_* constants.
1615 NUM_ACTUALS is the number of arguments.
1617 ARGS is an array containing information for each argument; this
1618 routine fills in the INITIAL_VALUE and VALUE fields for each
1619 precomputed argument. */
1621 static void
1623 {
1626 /* If this is a libcall, then precompute all arguments so that we do not
1627 get extraneous instructions emitted as part of the libcall sequence. */
1629 /* If we preallocated the stack space, and some arguments must be passed
1630 on the stack, then we must precompute any parameter which contains a
1631 function call which will store arguments on the stack.
1632 Otherwise, evaluating the parameter may clobber previous parameters
1633 which have already been stored into the stack. (we have code to avoid
1634 such case by saving the outgoing stack arguments, but it results in
1635 worse code) */
1640 {
1641 tree type;
1642 machine_mode mode;
1647 /* If this is an addressable type, we cannot pre-evaluate it. */
1656 {
1662 /* CSE will replace this only if it contains args[i].value
1663 pseudo, so convert it down to the declared mode using
1664 a SUBREG. */
1668 {
1673 }
1674 }
1675 }
1676 }
1678 /* Given the current state of MUST_PREALLOCATE and information about
1679 arguments to a function call in NUM_ACTUALS, ARGS and ARGS_SIZE,
1680 compute and return the final value for MUST_PREALLOCATE. */
1682 static int
1685 {
1686 /* See if we have or want to preallocate stack space.
1688 If we would have to push a partially-in-regs parm
1689 before other stack parms, preallocate stack space instead.
1691 If the size of some parm is not a multiple of the required stack
1692 alignment, we must preallocate.
1694 If the total size of arguments that would otherwise create a copy in
1695 a temporary (such as a CALL) is more than half the total argument list
1696 size, preallocation is faster.
1698 Another reason to preallocate is if we have a machine (like the m88k)
1699 where stack alignment is required to be maintained between every
1700 pair of insns, not just when the call is made. However, we assume here
1701 that such machines either do not have push insns (and hence preallocation
1702 would occur anyway) or the problem is taken care of with
1703 PUSH_ROUNDING. */
1706 {
1712 {
1717 /* We preallocate in case there are bounds passed
1718 in the bounds table to have precomputed address
1719 for bounds association. */
1729 copy_to_evaluate_size
1731 }
1736 }
1738 }
1740 /* If we preallocated stack space, compute the address of each argument
1741 and store it into the ARGS array.
1743 We need not ensure it is a valid memory address here; it will be
1744 validized when it is used.
1746 ARGBLOCK is an rtx for the address of the outgoing arguments. */
1748 static void
1750 {
1752 {
1760 {
1763 rtx addr;
1768 /* Skip this parm if it will not be passed on the stack. */
1774 /* Pointer Bounds are never passed on the stack. */
1780 else
1786 {
1787 /* Only part of the parameter is being passed on the stack.
1788 Generate a simple memory reference of the correct size. */
1794 }
1795 else
1796 {
1800 }
1806 {
1809 }
1814 else
1820 {
1821 /* Only part of the parameter is being passed on the stack.
1822 Generate a simple memory reference of the correct size.
1823 */
1826 }
1827 else
1828 {
1832 }
1835 /* Function incoming arguments may overlap with sibling call
1836 outgoing arguments and we cannot allow reordering of reads
1837 from function arguments with stores to outgoing arguments
1838 of sibling calls. */
1841 }
1842 }
1843 }
1845 /* Given a FNDECL and EXP, return an rtx suitable for use as a target address
1846 in a call instruction.
1848 FNDECL is the tree node for the target function. For an indirect call
1849 FNDECL will be NULL_TREE.
1851 ADDR is the operand 0 of CALL_EXPR for this call. */
1853 static rtx
1855 {
1856 rtx funexp;
1858 /* Get the function to call, in the form of RTL. */
1860 {
1864 /* Get a SYMBOL_REF rtx for the function address. */
1866 }
1867 else
1868 /* Generate an rtx (probably a pseudo-register) for the address. */
1869 {
1873 }
1875 }
1877 /* Internal state for internal_arg_pointer_based_exp and its helpers. */
1878 static struct
1879 {
1880 /* Last insn that has been scanned by internal_arg_pointer_based_exp_scan,
1881 or NULL_RTX if none has been scanned yet. */
1883 /* Vector indexed by REGNO - FIRST_PSEUDO_REGISTER, recording if a pseudo is
1884 based on crtl->args.internal_arg_pointer. The element is NULL_RTX if the
1885 pseudo isn't based on it, a CONST_INT offset if the pseudo is based on it
1886 with fixed offset, or PC if this is with variable or unknown offset. */
1892 /* Helper function for internal_arg_pointer_based_exp. Scan insns in
1893 the tail call sequence, starting with first insn that hasn't been
1894 scanned yet, and note for each pseudo on the LHS whether it is based
1895 on crtl->args.internal_arg_pointer or not, and what offset from that
1896 that pointer it has. */
1898 static void
1900 {
1905 else
1909 {
1912 {
1915 /* Punt on pseudos set multiple times. */
1920 else
1923 {
1925 internal_arg_pointer_exp_state.cache
1928 }
1929 }
1933 }
1936 }
1938 /* Compute whether RTL is based on crtl->args.internal_arg_pointer. Return
1939 NULL_RTX if RTL isn't based on it, a CONST_INT offset if RTL is based on
1940 it with fixed offset, or PC if this is with variable or unknown offset.
1941 TOPLEVEL is true if the function is invoked at the topmost level. */
1943 static rtx
1945 {
1956 {
1961 }
1963 /* When called at the topmost level, scan pseudo assignments in between the
1964 last scanned instruction in the tail call sequence and the latest insn
1965 in that sequence. */
1970 {
1976 }
1980 {
1986 }
1989 }
1991 /* Return true if and only if SIZE storage units (usually bytes)
1992 starting from address ADDR overlap with already clobbered argument
1993 area. This function is used to determine if we should give up a
1994 sibcall. */
1996 static bool
1998 {
1999 HOST_WIDE_INT i;
2000 rtx val;
2009 else
2014 else
2022 {
2029 }
2032 }
2034 /* Do the register loads required for any wholly-register parms or any
2035 parms which are passed both on the stack and in a register. Their
2036 expressions were already evaluated.
2038 Mark all register-parms as living through the call, putting these USE
2039 insns in the CALL_INSN_FUNCTION_USAGE field.
2041 When IS_SIBCALL, perform the check_sibcall_argument_overlap
2042 checking, setting *SIBCALL_FAILURE if appropriate. */
2044 static void
2048 {
2052 {
2056 {
2061 /* Set non-negative if we must move a word at a time, even if
2062 just one word (e.g, partial == 4 && mode == DFmode). Set
2063 to -1 if we just use a normal move insn. This value can be
2064 zero if the argument is a zero size structure. */
2067 ;
2069 {
2072 }
2074 {
2077 }
2078 else
2081 /* Handle calls that pass values in multiple non-contiguous
2082 locations. The Irix 6 ABI has examples of this. */
2087 /* If simple case, just do move. If normal partial, store_one_arg
2088 has already loaded the register for us. In all other cases,
2089 load the register(s) from memory. */
2092 {
2094 #ifdef BLOCK_REG_PADDING
2095 /* Handle case where we have a value that needs shifting
2096 up to the msb. eg. a QImode value and we're padding
2097 upward on a BYTES_BIG_ENDIAN machine. */
2101 {
2102 rtx x;
2105 /* Assigning REG here rather than a temp makes CALL_FUSAGE
2106 report the whole reg as used. Strictly speaking, the
2107 call only uses SIZE bytes at the msb end, but it doesn't
2108 seem worth generating rtl to say that. */
2113 }
2114 #endif
2115 }
2117 /* If we have pre-computed the values to put in the registers in
2118 the case of non-aligned structures, copy them in now. */
2126 {
2129 /* Check for overlap with already clobbered argument area,
2130 providing that this has non-zero size. */
2133 && (mem_overlaps_already_clobbered_arg_p
2140 else
2141 {
2155 }
2157 /* Handle a BLKmode that needs shifting. */
2159 #ifdef BLOCK_REG_PADDING
2161 #else
2162 && BYTES_BIG_ENDIAN
2163 #endif
2164 )
2165 {
2170 rtx x;
2175 }
2176 }
2178 /* When a parameter is a block, and perhaps in other cases, it is
2179 possible that it did a load from an argument slot that was
2180 already clobbered. */
2185 /* Handle calls that pass values in multiple non-contiguous
2186 locations. The Irix 6 ABI has examples of this. */
2194 }
2195 }
2196 }
2198 /* We need to pop PENDING_STACK_ADJUST bytes. But, if the arguments
2199 wouldn't fill up an even multiple of PREFERRED_UNIT_STACK_BOUNDARY
2200 bytes, then we would need to push some additional bytes to pad the
2201 arguments. So, we compute an adjust to the stack pointer for an
2202 amount that will leave the stack under-aligned by UNADJUSTED_ARGS_SIZE
2203 bytes. Then, when the arguments are pushed the stack will be perfectly
2204 aligned. ARGS_SIZE->CONSTANT is set to the number of bytes that should
2205 be popped after the call. Returns the adjustment. */
2207 static int
2211 {
2212 /* The number of bytes to pop so that the stack will be
2213 under-aligned by UNADJUSTED_ARGS_SIZE bytes. */
2214 HOST_WIDE_INT adjustment;
2215 /* The alignment of the stack after the arguments are pushed, if we
2216 just pushed the arguments without adjust the stack here. */
2219 unadjusted_alignment
2223 /* We want to get rid of as many of the PENDING_STACK_ADJUST bytes
2224 as possible -- leaving just enough left to cancel out the
2225 UNADJUSTED_ALIGNMENT. In other words, we want to ensure that the
2226 PENDING_STACK_ADJUST is non-negative, and congruent to
2227 -UNADJUSTED_ALIGNMENT modulo the PREFERRED_UNIT_STACK_BOUNDARY. */
2229 /* Begin by trying to pop all the bytes. */
2230 unadjusted_alignment
2231 = (unadjusted_alignment
2234 /* Push enough additional bytes that the stack will be aligned
2235 after the arguments are pushed. */
2237 {
2240 else
2242 }
2244 /* Now, sets ARGS_SIZE->CONSTANT so that we pop the right number of
2245 bytes after the call. The right number is the entire
2246 PENDING_STACK_ADJUST less our ADJUSTMENT plus the amount required
2247 by the arguments in the first place. */
2248 args_size->constant
2252 }
2254 /* Scan X expression if it does not dereference any argument slots
2255 we already clobbered by tail call arguments (as noted in stored_args_map
2256 bitmap).
2257 Return nonzero if X expression dereferences such argument slots,
2258 zero otherwise. */
2260 static int
2262 {
2263 RTX_CODE code;
2272 /* We need not check the operands of the CALL expression itself. */
2280 /* Scan all subexpressions. */
2283 {
2285 {
2288 }
2290 {
2294 }
2295 }
2297 }
2299 /* Scan sequence after INSN if it does not dereference any argument slots
2300 we already clobbered by tail call arguments (as noted in stored_args_map
2301 bitmap). If MARK_STORED_ARGS_MAP, add stack slots for ARG to
2302 stored_args_map bitmap afterwards (when ARG is a register MARK_STORED_ARGS_MAP
2303 should be 0). Return nonzero if sequence after INSN dereferences such argument
2304 slots, zero otherwise. */
2306 static int
2309 {
2314 else
2323 {
2326 else
2331 }
2333 }
2335 /* Given that a function returns a value of mode MODE at the most
2336 significant end of hard register VALUE, shift VALUE left or right
2337 as specified by LEFT_P. Return true if some action was needed. */
2339 bool
2341 {
2342 HOST_WIDE_INT shift;
2349 /* Use ashr rather than lshr for right shifts. This is for the benefit
2350 of the MIPS port, which requires SImode values to be sign-extended
2351 when stored in 64-bit registers. */
2356 }
2358 /* If X is a likely-spilled register value, copy it to a pseudo
2359 register and return that register. Return X otherwise. */
2361 static rtx
2363 {
2364 rtx new_rtx;
2369 {
2370 /* Make sure that we generate a REG rather than a CONCAT.
2371 Moves into CONCATs can need nontrivial instructions,
2372 and the whole point of this function is to avoid
2373 using the hard register directly in such a situation. */
2379 }
2381 }
2383 /* Helper function for expand_call.
2384 Return false is EXP is not implementable as a sibling call. */
2386 static bool
2388 rtx structure_value_addr,
2389 tree funtype,
2391 tree fndecl,
2393 tree addr,
2395 {
2397 {
2398 maybe_complain_about_tail_call
2400 "machine description does not have"
2403 }
2405 /* Doing sibling call optimization needs some work, since
2406 structure_value_addr can be allocated on the stack.
2407 It does not seem worth the effort since few optimizable
2408 sibling calls will return a structure. */
2410 {
2413 }
2415 #ifdef REG_PARM_STACK_SPACE
2416 /* If outgoing reg parm stack space changes, we can not do sibcall. */
2420 {
2422 "inconsistent size of stack space"
2423 " allocated for arguments which are"
2426 }
2427 #endif
2429 /* Check whether the target is able to optimize the call
2430 into a sibcall. */
2432 {
2434 "target is not able to optimize the"
2437 }
2439 /* Functions that do not return exactly once may not be sibcall
2440 optimized. */
2442 {
2445 }
2447 {
2450 }
2453 {
2456 }
2458 /* If the called function is nested in the current one, it might access
2459 some of the caller's arguments, but could clobber them beforehand if
2460 the argument areas are shared. */
2462 {
2465 }
2467 /* If this function requires more stack slots than the current
2468 function, we cannot change it into a sibling call.
2469 crtl->args.pretend_args_size is not part of the
2470 stack allocated by our caller. */
2472 {
2474 "callee required more stack slots"
2477 }
2479 /* If the callee pops its own arguments, then it must pop exactly
2480 the same number of arguments as the current function. */
2485 {
2487 "inconsistent number of"
2490 }
2493 {
2497 }
2499 /* All checks passed. */
2501 }
2503 /* Generate all the code for a CALL_EXPR exp
2504 and return an rtx for its value.
2505 Store the value in TARGET (specified as an rtx) if convenient.
2506 If the value is stored in TARGET then TARGET is returned.
2507 If IGNORE is nonzero, then we ignore the value of the function call. */
2509 rtx
2511 {
2512 /* Nonzero if we are currently expanding a call. */
2515 /* RTX for the function to be called. */
2516 rtx funexp;
2517 /* Sequence of insns to perform a normal "call". */
2519 /* Sequence of insns to perform a tail "call". */
2521 /* Data type of the function. */
2522 tree funtype;
2523 tree type_arg_types;
2524 tree rettype;
2525 /* Declaration of the function being called,
2526 or 0 if the function is computed (not known by name). */
2528 /* The type of the function being called. */
2529 tree fntype;
2534 /* Register in which non-BLKmode value will be returned,
2535 or 0 if no value or if value is BLKmode. */
2536 rtx valreg;
2537 /* Register(s) in which bounds are returned. */
2539 /* Address where we should return a BLKmode value;
2540 0 if value not BLKmode. */
2542 /* Nonzero if that address is being passed by treating it as
2543 an extra, implicit first parameter. Otherwise,
2544 it is passed by being copied directly into struct_value_rtx. */
2546 /* Holds the value of implicit argument for the struct value. */
2548 /* Size of aggregate value wanted, or zero if none wanted
2549 or if we are using the non-reentrant PCC calling convention
2550 or expecting the value in registers. */
2552 /* Nonzero if called function returns an aggregate in memory PCC style,
2553 by returning the address of where to find it. */
2557 /* Number of actual parameters in this call, including struct value addr. */
2559 /* Number of named args. Args after this are anonymous ones
2560 and they must all go on the stack. */
2562 /* Number of complex actual arguments that need to be split. */
2565 /* Vector of information about each argument.
2566 Arguments are numbered in the order they will be pushed,
2567 not the order they are written. */
2570 /* Total size in bytes of all the stack-parms scanned so far. */
2573 /* Size of arguments before any adjustments (such as rounding). */
2575 /* Data on reg parms scanned so far. */
2576 CUMULATIVE_ARGS args_so_far_v;
2577 cumulative_args_t args_so_far;
2578 /* Nonzero if a reg parm has been scanned. */
2580 /* Nonzero if this is an indirect function call. */
2582 /* Nonzero if we must avoid push-insns in the args for this call.
2583 If stack space is allocated for register parameters, but not by the
2584 caller, then it is preallocated in the fixed part of the stack frame.
2585 So the entire argument block must then be preallocated (i.e., we
2586 ignore PUSH_ROUNDING in that case). */
2590 /* Size of the stack reserved for parameter registers. */
2593 /* Address of space preallocated for stack parms
2594 (on machines that lack push insns), or 0 if space not preallocated. */
2597 /* Mask of ECF_ and ERF_ flags. */
2600 #ifdef REG_PARM_STACK_SPACE
2601 /* Define the boundary of the register parm stack space that needs to be
2602 saved, if any. */
2605 #endif
2613 /* State variables to track stack modifications. */
2619 /* Some stack pointer alterations we make are performed via
2620 allocate_dynamic_stack_space. This modifies the stack_pointer_delta,
2621 which we then also need to save/restore along the way. */
2624 rtx call_fusage;
2627 /* The alignment of the stack, in bits. */
2629 /* The alignment of the stack, in bytes. */
2631 /* The static chain value to use for this call. */
2632 rtx static_chain_value;
2633 /* See if this is "nothrow" function call. */
2637 /* See if we can find a DECL-node for the actual function, and get the
2638 function attributes (flags) from the function decl or type node. */
2641 {
2645 }
2646 else
2647 {
2650 }
2655 /* Warn if this value is an aggregate type,
2656 regardless of which calling convention we are using for it. */
2660 /* If the result of a non looping pure or const function call is
2661 ignored (or void), and none of its arguments are volatile, we can
2662 avoid expanding the call and just evaluate the arguments for
2663 side-effects. */
2668 {
2670 tree arg;
2671 call_expr_arg_iterator iter;
2675 {
2678 }
2681 {
2685 }
2686 }
2688 #ifdef REG_PARM_STACK_SPACE
2690 #endif
2696 /* Set up a place to return a structure. */
2698 /* Cater to broken compilers. */
2700 {
2701 /* This call returns a big structure. */
2704 #ifdef PCC_STATIC_STRUCT_RETURN
2705 {
2707 }
2709 {
2712 /* Even if it is semantically safe to use the target as the return
2713 slot, it may be not sufficiently aligned for the return type. */
2715 && target
2721 else
2722 {
2723 /* For variable-sized objects, we must be called with a target
2724 specified. If we were to allocate space on the stack here,
2725 we would have no way of knowing when to free it. */
2729 }
2730 }
2732 }
2734 /* Figure out the amount to which the stack should be aligned. */
2737 {
2739 /* Without automatic stack alignment, we can't increase preferred
2740 stack boundary. With automatic stack alignment, it is
2741 unnecessary since unless we can guarantee that all callers will
2742 align the outgoing stack properly, callee has to align its
2743 stack anyway. */
2748 }
2750 /* Operand 0 is a pointer-to-function; get the type of the function. */
2755 /* Count whether there are actual complex arguments that need to be split
2756 into their real and imaginary parts. Munge the type_arg_types
2757 appropriately here as well. */
2759 {
2760 call_expr_arg_iterator iter;
2761 tree arg;
2763 {
2767 num_complex_actuals++;
2768 }
2770 }
2771 else
2777 /* If struct_value_rtx is 0, it means pass the address
2778 as if it were an extra parameter. Put the argument expression
2779 in structure_value_addr_value. */
2781 {
2782 /* If structure_value_addr is a REG other than
2783 virtual_outgoing_args_rtx, we can use always use it. If it
2784 is not a REG, we must always copy it into a register.
2785 If it is virtual_outgoing_args_rtx, we must copy it to another
2786 register in some cases. */
2788 || (ACCUMULATE_OUTGOING_ARGS
2789 && stack_arg_under_construction
2795 structure_value_addr_value =
2798 }
2800 /* Count the arguments and set NUM_ACTUALS. */
2801 num_actuals =
2804 /* Compute number of named args.
2805 First, do a raw count of the args for INIT_CUMULATIVE_ARGS. */
2808 n_named_args
2810 /* Count the struct value address, if it is passed as a parm. */
2812 else
2813 /* If we know nothing, treat all args as named. */
2816 /* Start updating where the next arg would go.
2818 On some machines (such as the PA) indirect calls have a different
2819 calling convention than normal calls. The fourth argument in
2820 INIT_CUMULATIVE_ARGS tells the backend if this is an indirect call
2821 or not. */
2825 /* Now possibly adjust the number of named args.
2826 Normally, don't include the last named arg if anonymous args follow.
2827 We do include the last named arg if
2828 targetm.calls.strict_argument_naming() returns nonzero.
2829 (If no anonymous args follow, the result of list_length is actually
2830 one too large. This is harmless.)
2832 If targetm.calls.pretend_outgoing_varargs_named() returns
2833 nonzero, and targetm.calls.strict_argument_naming() returns zero,
2834 this machine will be able to place unnamed args that were passed
2835 in registers into the stack. So treat all args as named. This
2836 allows the insns emitting for a specific argument list to be
2837 independent of the function declaration.
2839 If targetm.calls.pretend_outgoing_varargs_named() returns zero,
2840 we do not have any reliable way to pass unnamed args in
2841 registers, so we must force them into memory. */
2845 ;
2848 /* Don't include the last named arg. */
2850 else
2851 /* Treat all args as named. */
2854 /* Make a vector to hold all the information about each arg. */
2858 /* Build up entries in the ARGS array, compute the size of the
2859 arguments into ARGS_SIZE, etc. */
2871 /* Now make final decision about preallocating stack space. */
2876 /* If the structure value address will reference the stack pointer, we
2877 must stabilize it. We don't need to do this if we know that we are
2878 not going to adjust the stack pointer in processing this call. */
2883 structure_value_addr))
2888 /* Tail calls can make things harder to debug, and we've traditionally
2889 pushed these optimizations into -O2. Don't try if we're already
2890 expanding a call, as that means we're an argument. Don't try if
2891 there's cleanups, as we know there's code to follow the call. */
2894 || !flag_optimize_sibling_calls
2899 /* If the user has marked the function as requiring tail-call
2900 optimization, attempt it. */
2904 /* Rest of purposes for tail call optimizations to fail. */
2907 structure_value_addr,
2908 funtype,
2909 reg_parm_stack_space,
2910 fndecl,
2913 /* Check if caller and callee disagree in promotion of function
2914 return value. */
2916 {
2926 caller_promoted_mode
2930 callee_promoted_mode
2941 {
2944 "caller and callee disagree in"
2945 " promotion of function"
2947 }
2948 }
2950 /* Ensure current function's preferred stack boundary is at least
2951 what we need. Stack alignment may also increase preferred stack
2952 boundary. */
2955 else
2960 /* We want to make two insn chains; one for a sibling call, the other
2961 for a normal call. We will select one of the two chains after
2962 initial RTL generation is complete. */
2964 {
2966 /* We want to emit any pending stack adjustments before the tail
2967 recursion "call". That way we know any adjustment after the tail
2968 recursion call can be ignored if we indeed use the tail
2969 call expansion. */
2970 saved_pending_stack_adjust save;
2972 rtx next_arg_reg;
2975 {
2976 /* State variables we need to save and restore between
2977 iterations. */
2979 }
2982 else
2985 /* Other state variables that we must reinitialize each time
2986 through the loop (that are not initialized by the loop itself). */
2990 /* Start a new sequence for the normal call case.
2992 From this point on, if the sibling call fails, we want to set
2993 sibcall_failure instead of continuing the loop. */
2996 /* Don't let pending stack adjusts add up to too much.
2997 Also, do all pending adjustments now if there is any chance
2998 this might be a call to alloca or if we are expanding a sibling
2999 call sequence.
3000 Also do the adjustments before a throwing call, otherwise
3001 exception handling can fail; PR 19225. */
3010 /* Precompute any arguments as needed. */
3014 /* Now we are about to start emitting insns that can be deleted
3015 if a libcall is deleted. */
3023 /* Compute the actual size of the argument block required. The variable
3024 and constant sizes must be combined, the size may have to be rounded,
3025 and there may be a minimum required size. When generating a sibcall
3026 pattern, do not round up, since we'll be re-using whatever space our
3027 caller provided. */
3028 unadjusted_args_size
3037 /* The argument block when performing a sibling call is the
3038 incoming argument block. */
3040 {
3043 argblock
3045 else
3046 argblock
3051 }
3053 /* If we have no actual push instructions, or shouldn't use them,
3054 make space for all args right now. */
3056 {
3058 {
3063 /* stack_arg_under_construction says whether a stack arg is
3064 being constructed at the old stack level. Pushing the stack
3065 gets a clean outgoing argument block. */
3068 }
3072 }
3073 else
3074 {
3075 /* Note that we must go through the motions of allocating an argument
3076 block even if the size is zero because we may be storing args
3077 in the area reserved for register arguments, which may be part of
3078 the stack frame. */
3082 /* Store the maximum argument space used. It will be pushed by
3083 the prologue (if ACCUMULATE_OUTGOING_ARGS, or stack overflow
3084 checking). */
3090 {
3092 {
3093 /* Since the stack pointer will never be pushed, it is
3094 possible for the evaluation of a parm to clobber
3095 something we have already written to the stack.
3096 Since most function calls on RISC machines do not use
3097 the stack, this is uncommon, but must work correctly.
3099 Therefore, we save any area of the stack that was already
3100 written and that we are using. Here we set up to do this
3101 by making a new stack usage map from the old one. The
3102 actual save will be done by store_one_arg.
3104 Another approach might be to try to reorder the argument
3105 evaluations to avoid this conflicting stack usage. */
3107 /* Since we will be writing into the entire argument area,
3108 the map must be allocated for its entire size, not just
3109 the part that is the responsibility of the caller. */
3114 highest_outgoing_arg_in_use
3116 else
3117 highest_outgoing_arg_in_use
3126 initial_highest_arg_in_use);
3130 (highest_outgoing_arg_in_use
3134 /* The address of the outgoing argument list must not be
3135 copied to a register here, because argblock would be left
3136 pointing to the wrong place after the call to
3137 allocate_dynamic_stack_space below. */
3140 }
3141 else
3142 {
3144 {
3145 /* Try to reuse some or all of the pending_stack_adjust
3146 to get this space. */
3147 needed
3148 = (combine_pending_stack_adjustment_and_call
3151 preferred_unit_stack_boundary));
3153 /* combine_pending_stack_adjustment_and_call computes
3154 an adjustment before the arguments are allocated.
3155 Account for them and see whether or not the stack
3156 needs to go up or down. */
3160 {
3161 /* We're releasing stack space. */
3162 /* ??? We can avoid any adjustment at all if we're
3163 already aligned. FIXME. */
3167 }
3168 else
3169 /* We need to allocate space. We'll do that in
3170 push_block below. */
3172 }
3174 /* Special case this because overhead of `push_block' in
3175 this case is non-trivial. */
3178 else
3179 {
3183 }
3185 /* We only really need to call `copy_to_reg' in the case
3186 where push insns are going to be used to pass ARGBLOCK
3187 to a function call in ARGS. In that case, the stack
3188 pointer changes value from the allocation point to the
3189 call point, and hence the value of
3190 VIRTUAL_OUTGOING_ARGS_RTX changes as well. But might
3191 as well always do it. */
3193 }
3194 }
3195 }
3198 {
3199 /* The save/restore code in store_one_arg handles all
3200 cases except one: a constructor call (including a C
3201 function returning a BLKmode struct) to initialize
3202 an argument. */
3204 {
3205 rtx push_size
3211 {
3216 /* stack_arg_under_construction says whether a stack
3217 arg is being constructed at the old stack level.
3218 Pushing the stack gets a clean outgoing argument
3219 block. */
3220 old_stack_arg_under_construction
3223 /* Make a new map for the new argument list. */
3228 }
3229 /* We can pass TRUE as the 4th argument because we just
3230 saved the stack pointer and will restore it right after
3231 the call. */
3234 }
3236 /* If argument evaluation might modify the stack pointer,
3237 copy the address of the argument list to a register. */
3240 {
3243 }
3244 }
3248 /* Stack is properly aligned, pops can't safely be deferred during
3249 the evaluation of the arguments. */
3250 NO_DEFER_POP;
3252 /* Precompute all register parameters. It isn't safe to compute
3253 anything once we have started filling any specific hard regs.
3254 TLS symbols sometimes need a call to resolve. Precompute
3255 register parameters before any stack pointer manipulation
3256 to avoid unaligned stack in the called function. */
3259 OK_DEFER_POP;
3261 /* Perform stack alignment before the first push (the last arg). */
3265 {
3266 /* When the stack adjustment is pending, we get better code
3267 by combining the adjustments. */
3270 {
3271 pending_stack_adjust
3272 = (combine_pending_stack_adjustment_and_call
3275 preferred_unit_stack_boundary));
3277 }
3281 }
3282 /* Now that the stack is properly aligned, pops can't safely
3283 be deferred during the evaluation of the arguments. */
3284 NO_DEFER_POP;
3286 /* Record the maximum pushed stack space size. We need to delay
3287 doing it this far to take into account the optimization done
3288 by combine_pending_stack_adjustment_and_call. */
3290 && !ACCUMULATE_OUTGOING_ARGS
3291 && pass
3293 {
3297 }
3303 else
3306 #ifdef REG_PARM_STACK_SPACE
3307 /* Save the fixed argument area if it's part of the caller's frame and
3308 is clobbered by argument setup for this call. */
3312 #endif
3314 /* Now store (and compute if necessary) all non-register parms.
3315 These come before register parms, since they can require block-moves,
3316 which could clobber the registers used for register parms.
3317 Parms which have partial registers are not stored here,
3318 but we do preallocate space here if they want that. */
3321 {
3322 /* Delay bounds until all other args are stored. */
3326 {
3329 /* We don't allow passing huge (> 2^30 B) arguments
3330 by value. It would cause an overflow later on. */
3333 {
3336 }
3340 reg_parm_stack_space)
3345 }
3348 call_fusage
3351 call_fusage);
3352 }
3354 /* If we have a parm that is passed in registers but not in memory
3355 and whose alignment does not permit a direct copy into registers,
3356 make a group of pseudos that correspond to each register that we
3357 will later fill. */
3361 /* Now store any partially-in-registers parm.
3362 This is the last place a block-move can happen. */
3366 {
3369 /* On targets with weird calling conventions (e.g. PA) it's
3370 hard to ensure that all cases of argument overlap between
3371 stack and registers work. Play it safe and bail out. */
3373 {
3376 }
3380 reg_parm_stack_space)
3385 }
3390 {
3393 }
3397 /* Figure out the register where the value, if any, will come back. */
3402 {
3404 {
3411 }
3412 else
3413 {
3418 fndecl,
3420 }
3422 /* If VALREG is a PARALLEL whose first member has a zero
3423 offset, use that. This is for targets such as m68k that
3424 return the same value in multiple places. */
3426 {
3433 }
3434 }
3436 /* Store all bounds not passed in registers. */
3438 {
3443 ? NULL
3445 }
3447 /* If register arguments require space on the stack and stack space
3448 was not preallocated, allocate stack space here for arguments
3449 passed in registers. */
3451 && !ACCUMULATE_OUTGOING_ARGS
3455 /* Pass the function the address in which to return a
3456 structure value. */
3458 {
3459 structure_value_addr
3464 NULL_RTX)));
3468 }
3478 /* Save a pointer to the last insn before the call, so that we can
3479 later safely search backwards to find the CALL_INSN. */
3482 /* Set up next argument register. For sibling calls on machines
3483 with register windows this should be the incoming register. */
3486 VOIDmode,
3487 void_type_node,
3489 else
3495 {
3501 && valreg
3504 call_fusage
3507 call_fusage);
3508 }
3509 /* All arguments and registers used for the call must be set up by
3510 now! */
3512 /* Stack must be properly aligned now. */
3516 /* Generate the actual call instruction. */
3523 {
3527 {
3531 }
3534 }
3536 /* If the call setup or the call itself overlaps with anything
3537 of the argument setup we probably clobbered our call address.
3538 In that case we can't do sibcalls. */
3543 /* If a non-BLKmode value is returned at the most significant end
3544 of a register, shift the register right by the appropriate amount
3545 and update VALREG accordingly. BLKmode values are handled by the
3546 group load/store machinery below. */
3548 && !pcc_struct_value
3553 {
3557 }
3560 {
3564 /* The return value from a malloc-like function is a pointer. */
3570 /* The return value from a malloc-like function can not alias
3571 anything else. */
3575 /* Write out the sequence. */
3580 }
3582 /* For calls to `setjmp', etc., inform
3583 function.c:setjmp_warnings that it should complain if
3584 nonvolatile values are live. For functions that cannot
3585 return, inform flow that control does not fall through. */
3588 {
3589 /* The barrier must be emitted
3590 immediately after the CALL_INSN. Some ports emit more
3591 than just a CALL_INSN above, so we must search for it here. */
3595 {
3597 /* There was no CALL_INSN? */
3599 }
3603 /* Stack adjustments after a noreturn call are dead code.
3604 However when NO_DEFER_POP is in effect, we must preserve
3605 stack_pointer_delta. */
3607 {
3610 }
3611 }
3613 /* If value type not void, return an rtx for the value. */
3619 {
3621 {
3622 target
3625 structure_value_addr));
3627 }
3628 }
3630 {
3631 /* This is the special C++ case where we need to
3632 know what the true target was. We take care to
3633 never use this value more than once in one expression. */
3637 }
3638 /* Handle calls that return values in multiple non-contiguous locations.
3639 The Irix 6 ABI has examples of this. */
3641 {
3645 ;
3647 /* Handle the result of a emit_group_move_into_temps
3648 call in the previous pass. */
3650 else
3653 }
3657 {
3660 /* We have to copy a return value in a CLASS_LIKELY_SPILLED hard
3661 reg to a plain register. */
3665 /* If TARGET is a MEM in the argument area, and we have
3666 saved part of the argument area, then we can't store
3667 directly into TARGET as it may get overwritten when we
3668 restore the argument save area below. Don't work too
3669 hard though and simply force TARGET to a register if it
3670 is a MEM; the optimizer is quite likely to sort it out. */
3674 {
3677 }
3681 else
3682 {
3683 /* TARGET and VALREG cannot be equal at this point
3684 because the latter would not have
3685 REG_FUNCTION_VALUE_P true, while the former would if
3686 it were referring to the same register.
3688 If they refer to the same register, this move will be
3689 a no-op, except when function inlining is being
3690 done. */
3693 /* If we are setting a MEM, this code must be executed.
3694 Since it is emitted after the call insn, sibcall
3695 optimization cannot be performed in that case. */
3698 }
3699 }
3700 else
3703 /* If we promoted this return value, make the proper SUBREG.
3704 TARGET might be const0_rtx here, so be careful. */
3708 {
3712 machine_mode pmode;
3714 /* Ensure we promote as expected, and get the new unsignedness. */
3722 {
3729 }
3734 }
3736 /* If size of args is variable or this was a constructor call for a stack
3737 argument, restore saved stack-pointer value. */
3740 {
3754 }
3756 {
3757 #ifdef REG_PARM_STACK_SPACE
3761 #endif
3763 /* If we saved any argument areas, restore them. */
3766 {
3768 rtx stack_area
3775 else
3778 BLOCK_OP_CALL_PARM);
3779 }
3783 }
3785 /* If this was alloca, record the new stack level. */
3789 /* Free up storage we no longer need. */
3799 {
3802 /* Restore the pending stack adjustment now that we have
3803 finished generating the sibling call sequence. */
3807 /* Prepare arg structure for next iteration. */
3809 {
3813 }
3818 }
3819 else
3820 {
3823 /* Verify that we've deallocated all the stack we used. */
3825 || (old_stack_allocated
3827 }
3829 /* If something prevents making this a sibling call,
3830 zero out the sequence. */
3833 else
3835 }
3837 /* If tail call production succeeded, we need to remove REG_EQUIV notes on
3838 arguments too, as argument area is now clobbered by the call. */
3840 {
3843 }
3844 else
3845 {
3848 /* Ideally we'd emit a message for all of the ways that it could
3849 have failed. */
3851 }
3853 currently_expanding_call--;
3857 /* Join result with returned bounds so caller may use them if needed. */
3861 }
3863 /* A sibling call sequence invalidates any REG_EQUIV notes made for
3864 this function's incoming arguments.
3866 At the start of RTL generation we know the only REG_EQUIV notes
3867 in the rtl chain are those for incoming arguments, so we can look
3868 for REG_EQUIV notes between the start of the function and the
3869 NOTE_INSN_FUNCTION_BEG.
3871 This is (slight) overkill. We could keep track of the highest
3872 argument we clobber and be more selective in removing notes, but it
3873 does not seem to be worth the effort. */
3875 void
3877 {
3881 {
3882 rtx note;
3884 /* There are never REG_EQUIV notes for the incoming arguments
3885 after the NOTE_INSN_FUNCTION_BEG note, so stop if we see it. */
3895 }
3896 }
3898 /* Traverse a list of TYPES and expand all complex types into their
3899 components. */
3900 static tree
3902 {
3903 tree p;
3905 /* Before allocating memory, check for the common case of no complex. */
3907 {
3912 }
3915 found:
3919 {
3924 {
3927 /* Rewrite complex type with component type. */
3931 /* Add another component type for the imaginary part. */
3936 /* Skip the newly created node. */
3938 }
3939 }
3942 }
3943 \f
3944 /* Output a library call to function FUN (a SYMBOL_REF rtx).
3945 The RETVAL parameter specifies whether return value needs to be saved, other
3946 parameters are documented in the emit_library_call function below. */
3948 static rtx
3952 {
3953 /* Total size in bytes of all the stack-parms scanned so far. */
3955 /* Size of arguments before any adjustments (such as rounding). */
3958 rtx fun;
3959 /* Todo, choose the correct decl type of orgfun. Sadly this information
3960 isn't present here, so we default to native calling abi here. */
3965 CUMULATIVE_ARGS args_so_far_v;
3966 cumulative_args_t args_so_far;
3967 struct arg
3968 {
3969 rtx value;
3970 machine_mode mode;
3971 rtx reg;
3974 rtx save_area;
3975 };
3980 rtx valreg;
3990 #ifdef REG_PARM_STACK_SPACE
3991 /* Define the boundary of the register parm stack space that needs to be
3992 save, if any. */
3995 #endif
3997 /* Size of the stack reserved for parameter registers. */
4004 #ifdef REG_PARM_STACK_SPACE
4006 #endif
4008 /* By default, library functions cannot throw. */
4012 {
4030 }
4033 /* Ensure current function's preferred stack boundary is at least
4034 what we need. */
4038 /* If this kind of value comes back in memory,
4039 decide where in memory it should come back. */
4041 {
4044 {
4045 #ifdef PCC_STATIC_STRUCT_RETURN
4046 rtx pointer_reg
4056 else
4058 #endif
4059 /* This call returns a big structure. */
4061 }
4062 }
4063 else
4066 /* ??? Unfinished: must pass the memory address as an argument. */
4068 /* Copy all the libcall-arguments out of the varargs data
4069 and into a vector ARGVEC.
4071 Compute how to pass each argument. We only support a very small subset
4072 of the full argument passing conventions to limit complexity here since
4073 library functions shouldn't have many args. */
4078 #ifdef INIT_CUMULATIVE_LIBCALL_ARGS
4080 #else
4082 #endif
4092 /* If there's a structure value address to be passed,
4093 either pass it in the special place, or pass it as an extra argument. */
4095 {
4098 nargs++;
4100 /* Make sure it is a reasonable operand for a move or push insn. */
4116 #ifdef STACK_PARMS_IN_REG_PARM_AREA
4118 #else
4120 #endif
4130 count++;
4131 }
4134 {
4139 /* We cannot convert the arg value to the mode the library wants here;
4140 must do it earlier where we know the signedness of the arg. */
4144 /* Make sure it is a reasonable operand for a move or push insn. */
4150 {
4151 rtx slot;
4152 int must_copy
4155 /* If this was a CONST function, it is now PURE since it now
4156 reads memory. */
4158 {
4161 }
4164 {
4169 }
4170 else
4171 {
4175 }
4179 call_fusage);
4183 slot),
4184 call_fusage);
4188 }
4202 {
4204 #ifdef STACK_PARMS_IN_REG_PARM_AREA
4206 #else
4208 #endif
4213 }
4214 #ifdef BLOCK_REG_PADDING
4215 else
4216 /* The argument is passed entirely in registers. See at which
4217 end it should be padded. */
4221 #endif
4224 }
4226 /* If this machine requires an external definition for library
4227 functions, write one out. */
4232 + stack_pointer_delta
4234 / STACK_BYTES
4239 reg_parm_stack_space);
4248 {
4252 }
4255 {
4256 /* Since the stack pointer will never be pushed, it is possible for
4257 the evaluation of a parm to clobber something we have already
4258 written to the stack. Since most function calls on RISC machines
4259 do not use the stack, this is uncommon, but must work correctly.
4261 Therefore, we save any area of the stack that was already written
4262 and that we are using. Here we set up to do this by making a new
4263 stack usage map from the old one.
4265 Another approach might be to try to reorder the argument
4266 evaluations to avoid this conflicting stack usage. */
4270 /* Since we will be writing into the entire argument area, the
4271 map must be allocated for its entire size, not just the part that
4272 is the responsibility of the caller. */
4279 else
4287 initial_highest_arg_in_use);
4294 /* We must be careful to use virtual regs before they're instantiated,
4295 and real regs afterwards. Loop optimization, for example, can create
4296 new libcalls after we've instantiated the virtual regs, and if we
4297 use virtuals anyway, they won't match the rtl patterns. */
4301 STACK_POINTER_OFFSET);
4302 else
4304 }
4305 else
4306 {
4309 }
4311 /* We push args individually in reverse order, perform stack alignment
4312 before the first push (the last arg). */
4319 #ifdef REG_PARM_STACK_SPACE
4321 {
4322 /* The argument list is the property of the called routine and it
4323 may clobber it. If the fixed area has been used for previous
4324 parameters, we must save and restore it. */
4327 }
4328 #endif
4330 /* When expanding a normal call, args are stored in push order,
4331 which is the reverse of what we have here. */
4335 {
4338 }
4342 /* Push the args that need to be pushed. */
4346 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
4347 are to be pushed. */
4349 {
4358 {
4359 rtx use;
4362 {
4363 /* If this is being stored into a pre-allocated, fixed-size,
4364 stack area, save any previous data at that location. */
4367 {
4368 /* stack_slot is negative, but we want to index stack_usage_map
4369 with positive values. */
4372 }
4373 else
4374 {
4377 }
4380 /* Don't worry about things in the fixed argument area;
4381 it has already been saved. */
4385 i++;
4388 {
4389 /* We need to make a save area. */
4390 unsigned int size
4392 machine_mode save_mode
4394 rtx adr
4397 rtx stack_area
4401 {
4405 );
4409 stack_area,
4411 BLOCK_OP_CALL_PARM);
4412 }
4413 else
4414 {
4418 }
4419 }
4420 }
4425 reg_parm_stack_space,
4428 /* Now mark the segment we just used. */
4433 NO_DEFER_POP;
4435 /* Indicate argument access so that alias.c knows that these
4436 values are live. */
4442 else
4443 {
4444 /* When arguments are pushed, trying to tell alias.c where
4445 exactly this argument is won't work, because the
4446 auto-increment causes confusion. So we merely indicate
4447 that we access something with a known mode somewhere on
4448 the stack. */
4452 }
4456 }
4457 }
4463 /* Now load any reg parms into their regs. */
4465 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
4466 are to be pushed. */
4468 {
4473 #ifdef BLOCK_REG_PADDING
4475 #endif
4477 /* Handle calls that pass values in multiple non-contiguous
4478 locations. The PA64 has examples of this for library calls. */
4482 {
4484 #ifdef BLOCK_REG_PADDING
4487 /* Copied from load_register_parameters. */
4489 /* Handle case where we have a value that needs shifting
4490 up to the msb. eg. a QImode value and we're padding
4491 upward on a BYTES_BIG_ENDIAN machine. */
4495 {
4496 rtx x;
4499 /* Assigning REG here rather than a temp makes CALL_FUSAGE
4500 report the whole reg as used. Strictly speaking, the
4501 call only uses SIZE bytes at the msb end, but it doesn't
4502 seem worth generating rtl to say that. */
4507 }
4508 #endif
4509 }
4511 NO_DEFER_POP;
4512 }
4514 /* Any regs containing parms remain in use through the call. */
4516 {
4521 {
4524 {
4529 }
4530 else
4532 }
4533 }
4535 /* Pass the function the address in which to return a structure value. */
4537 {
4541 NULL_RTX)));
4544 }
4546 /* Don't allow popping to be deferred, since then
4547 cse'ing of library calls could delete a call and leave the pop. */
4548 NO_DEFER_POP;
4552 /* Stack must be properly aligned now. */
4558 /* We pass the old value of inhibit_defer_pop + 1 to emit_call_1, which
4559 will set inhibit_defer_pop to that value. */
4560 /* The return type is needed to decide how many bytes the function pops.
4561 Signedness plays no role in that, so for simplicity, we pretend it's
4562 always signed. We also assume that the list of arguments passed has
4563 no impact, so we pretend it is unknown. */
4569 struct_value_size,
4572 valreg,
4576 {
4581 }
4583 /* Right-shift returned value if necessary. */
4587 {
4590 }
4594 /* For calls to `setjmp', etc., inform function.c:setjmp_warnings
4595 that it should complain if nonvolatile values are live. For
4596 functions that cannot return, inform flow that control does not
4597 fall through. */
4599 {
4600 /* The barrier note must be emitted
4601 immediately after the CALL_INSN. Some ports emit more than
4602 just a CALL_INSN above, so we must search for it here. */
4605 {
4607 /* There was no CALL_INSN? */
4609 }
4612 }
4614 /* Consider that "regular" libcalls, i.e. all of them except for LCT_THROW
4615 and LCT_RETURNS_TWICE, cannot perform non-local gotos. */
4617 {
4620 {
4622 /* There was no CALL_INSN? */
4624 }
4627 }
4629 /* Now restore inhibit_defer_pop to its actual original value. */
4630 OK_DEFER_POP;
4634 /* Copy the value to the right place. */
4636 {
4638 {
4643 }
4645 {
4649 }
4650 else
4651 {
4652 /* Convert to the proper mode if a promotion has been active. */
4654 {
4661 }
4665 else
4667 }
4668 }
4671 {
4672 #ifdef REG_PARM_STACK_SPACE
4676 #endif
4678 /* If we saved any argument areas, restore them. */
4681 {
4690 validize_mem
4693 BLOCK_OP_CALL_PARM);
4694 else
4696 }
4700 }
4706 }
4707 \f
4708 /* Output a library call to function FUN (a SYMBOL_REF rtx)
4709 (emitting the queue unless NO_QUEUE is nonzero),
4710 for a value of mode OUTMODE,
4711 with NARGS different arguments, passed as alternating rtx values
4712 and machine_modes to convert them to.
4714 FN_TYPE should be LCT_NORMAL for `normal' calls, LCT_CONST for
4715 `const' calls, LCT_PURE for `pure' calls, or other LCT_ value for
4716 other types of library calls. */
4718 void
4721 {
4727 }
4728 \f
4729 /* Like emit_library_call except that an extra argument, VALUE,
4730 comes second and says where to store the result.
4731 (If VALUE is zero, this function chooses a convenient way
4732 to return the value.
4734 This function returns an rtx for where the value is to be found.
4735 If VALUE is nonzero, VALUE is returned. */
4737 rtx
4741 {
4742 rtx result;
4751 }
4752 \f
4754 /* Store pointer bounds argument ARG into Bounds Table entry
4755 associated with PARM. */
4756 static void
4758 {
4761 /* We may pass bounds not associated with any pointer. */
4763 {
4767 }
4768 /* Find pointer associated with bounds and where it is
4769 passed. */
4770 else
4771 {
4773 {
4777 }
4779 {
4787 else
4788 {
4791 }
4792 }
4793 else
4794 {
4803 else
4805 }
4806 }
4808 /* Expand bounds. */
4813 }
4815 /* Store a single argument for a function call
4816 into the register or memory area where it must be passed.
4817 *ARG describes the argument value and where to pass it.
4819 ARGBLOCK is the address of the stack-block for all the arguments,
4820 or 0 on a machine where arguments are pushed individually.
4822 MAY_BE_ALLOCA nonzero says this could be a call to `alloca'
4823 so must be careful about how the stack is used.
4825 VARIABLE_SIZE nonzero says that this was a variable-sized outgoing
4826 argument stack. This is used if ACCUMULATE_OUTGOING_ARGS to indicate
4827 that we need not worry about saving and restoring the stack.
4829 FNDECL is the declaration of the function we are calling.
4831 Return nonzero if this arg should cause sibcall failure,
4832 zero otherwise. */
4834 static int
4837 {
4848 /* Push a new temporary level for any temporaries we make for
4849 this argument. */
4853 {
4854 /* If this is being stored into a pre-allocated, fixed-size, stack area,
4855 save any previous data at that location. */
4857 {
4859 {
4860 /* stack_slot is negative, but we want to index stack_usage_map
4861 with positive values. */
4864 else
4868 }
4869 else
4870 {
4873 else
4877 }
4880 /* Don't worry about things in the fixed argument area;
4881 it has already been saved. */
4885 i++;
4888 {
4889 /* We need to make a save area. */
4896 {
4897 arg->save_area
4901 stack_area,
4903 BLOCK_OP_CALL_PARM);
4904 }
4905 else
4906 {
4909 }
4910 }
4911 }
4912 }
4914 /* If this isn't going to be placed on both the stack and in registers,
4915 set up the register and number of words. */
4917 {
4920 else
4923 }
4925 /* Being passed entirely in a register. We shouldn't be called in
4926 this case. */
4929 /* If this arg needs special alignment, don't load the registers
4930 here. */
4934 /* If this is being passed partially in a register, we can't evaluate
4935 it directly into its stack slot. Otherwise, we can. */
4937 {
4938 /* stack_arg_under_construction is nonzero if a function argument is
4939 being evaluated directly into the outgoing argument list and
4940 expand_call must take special action to preserve the argument list
4941 if it is called recursively.
4943 For scalar function arguments stack_usage_map is sufficient to
4944 determine which stack slots must be saved and restored. Scalar
4945 arguments in general have pass_on_stack == 0.
4947 If this argument is initialized by a function which takes the
4948 address of the argument (a C++ constructor or a C function
4949 returning a BLKmode structure), then stack_usage_map is
4950 insufficient and expand_call must push the stack around the
4951 function call. Such arguments have pass_on_stack == 1.
4953 Note that it is always safe to set stack_arg_under_construction,
4954 but this generates suboptimal code if set when not needed. */
4957 stack_arg_under_construction++;
4960 (partial
4965 /* If we are promoting object (or for any other reason) the mode
4966 doesn't agree, convert the mode. */
4973 stack_arg_under_construction--;
4974 }
4976 /* Check for overlap with already clobbered argument area. */
4983 /* Don't allow anything left on stack from computation
4984 of argument to alloca. */
4989 /* If the value is already in the stack slot, we are done. */
4990 ;
4992 {
4996 /* Argument is a scalar, not entirely passed in registers.
4997 (If part is passed in registers, arg->partial says how much
4998 and emit_push_insn will take care of putting it there.)
5000 Push it, and if its size is less than the
5001 amount of space allocated to it,
5002 also bump stack pointer by the additional space.
5003 Note that in C the default argument promotions
5004 will prevent such mismatches. */
5007 /* Compute how much space the push instruction will push.
5008 On many machines, pushing a byte will advance the stack
5009 pointer by a halfword. */
5010 #ifdef PUSH_ROUNDING
5012 #endif
5015 /* Compute how much space the argument should get:
5016 round up to a multiple of the alignment for arguments. */
5022 /* Compute the alignment of the pushed argument. */
5025 {
5028 {
5031 }
5032 }
5034 /* This isn't already where we want it on the stack, so put it there.
5035 This can either be done with push or copy insns. */
5042 /* Unless this is a partially-in-register argument, the argument is now
5043 in the stack. */
5046 }
5047 else
5048 {
5049 /* BLKmode, at least partly to be pushed. */
5053 rtx size_rtx;
5055 /* Pushing a nonscalar.
5056 If part is passed in registers, PARTIAL says how much
5057 and emit_push_insn will take care of putting it there. */
5059 /* Round its size up to a multiple
5060 of the allocation unit for arguments. */
5063 {
5066 }
5067 else
5068 {
5069 /* PUSH_ROUNDING has no effect on us, because emit_push_insn
5070 for BLKmode is careful to avoid it. */
5076 EXPAND_NORMAL);
5077 }
5081 /* When an argument is padded down, the block is aligned to
5082 PARM_BOUNDARY, but the actual argument isn't. */
5084 {
5088 {
5091 }
5092 }
5095 {
5096 /* emit_push_insn might not work properly if arg->value and
5097 argblock + arg->locate.offset areas overlap. */
5106 {
5110 /* arg.locate doesn't contain the pretend_args_size offset,
5111 it's part of argblock. Ensure we don't count it in I. */
5114 else
5117 /* expand_call should ensure this. */
5123 {
5126 }
5128 {
5129 /* Use arg->locate.size.constant instead of size_rtx
5130 because we only care about the part of the argument
5131 on the stack. */
5135 }
5136 else
5137 {
5138 /* Even though they appear to be at the same location,
5139 if part of the outgoing argument is in registers,
5140 they aren't really at the same location. Check for
5141 this by making sure that the incoming size is the
5142 same as the outgoing size. */
5145 }
5146 }
5147 }
5154 /* Unless this is a partially-in-register argument, the argument is now
5155 in the stack.
5157 ??? Unlike the case above, in which we want the actual
5158 address of the data, so that we can load it directly into a
5159 register, here we want the address of the stack slot, so that
5160 it's properly aligned for word-by-word copying or something
5161 like that. It's not clear that this is always correct. */
5164 }
5167 {
5169 arg->parallel_value
5172 }
5174 /* Mark all slots this store used. */
5180 /* Once we have pushed something, pops can't safely
5181 be deferred during the rest of the arguments. */
5182 NO_DEFER_POP;
5184 /* Free any temporary slots made in processing this argument. */
5188 }
5190 /* Nonzero if we do not know how to pass TYPE solely in registers. */
5192 bool
5194 const_tree type)
5195 {
5199 /* If the type has variable size... */
5203 /* If the type is marked as addressable (it is required
5204 to be constructed into the stack)... */
5209 }
5211 /* Another version of the TARGET_MUST_PASS_IN_STACK hook. This one
5212 takes trailing padding of a structure into account. */
5213 /* ??? Should be able to merge these two by examining BLOCK_REG_PADDING. */
5215 bool
5217 {
5221 /* If the type has variable size... */
5225 /* If the type is marked as addressable (it is required
5226 to be constructed into the stack)... */
5230 /* If the padding and mode of the type is such that a copy into
5231 a register would put it into the wrong part of the register. */
5239 }