| blob | ffb8a21f021cf7796d0da8371695395838a1cb0c |
1 /* Convert function calls to rtl insns, for GNU C compiler.
2 Copyright (C) 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998
3 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
10 version.
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
20 02111-1307, USA. */
42 /* Decide whether a function's arguments should be processed
43 from first to last or from last to first.
45 They should if the stack and args grow in opposite directions, but
46 only if we have push insns. */
48 #ifdef PUSH_ROUNDING
50 #ifndef PUSH_ARGS_REVERSED
51 #if defined (STACK_GROWS_DOWNWARD) != defined (ARGS_GROW_DOWNWARD)
52 #define PUSH_ARGS_REVERSED PUSH_ARGS
53 #endif
54 #endif
56 #endif
58 #ifndef PUSH_ARGS_REVERSED
59 #define PUSH_ARGS_REVERSED 0
60 #endif
62 #ifndef STACK_POINTER_OFFSET
63 #define STACK_POINTER_OFFSET 0
64 #endif
66 /* Like PREFERRED_STACK_BOUNDARY but in units of bytes, not bits. */
67 #define STACK_BYTES (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT)
69 /* Data structure and subroutines used within expand_call. */
71 struct arg_data
72 {
73 /* Tree node for this argument. */
74 tree tree_value;
75 /* Mode for value; TYPE_MODE unless promoted. */
77 /* Current RTL value for argument, or 0 if it isn't precomputed. */
78 rtx value;
79 /* Initially-compute RTL value for argument; only for const functions. */
80 rtx initial_value;
81 /* Register to pass this argument in, 0 if passed on stack, or an
82 PARALLEL if the arg is to be copied into multiple non-contiguous
83 registers. */
84 rtx reg;
85 /* Register to pass this argument in when generating tail call sequence.
86 This is not the same register as for normal calls on machines with
87 register windows. */
88 rtx tail_call_reg;
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 registers to use. 0 means put the whole arg in registers.
93 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 /* Offset of this argument from beginning of stack-args. */
102 /* Similar, but offset to the start of the stack slot. Different from
103 OFFSET if this arg pads downward. */
105 /* Size of this argument on the stack, rounded up for any padding it gets,
106 parts of the argument passed in registers do not count.
107 If REG_PARM_STACK_SPACE is defined, then register parms
108 are counted here as well. */
110 /* Location on the stack at which parameter should be stored. The store
111 has already been done if STACK == VALUE. */
112 rtx stack;
113 /* Location on the stack of the start of this argument slot. This can
114 differ from STACK if this arg pads downward. This location is known
115 to be aligned to FUNCTION_ARG_BOUNDARY. */
116 rtx stack_slot;
117 /* Place that this stack area has been saved, if needed. */
118 rtx save_area;
119 /* If an argument's alignment does not permit direct copying into registers,
120 copy in smaller-sized pieces into pseudos. These are stored in a
121 block pointed to by this field. The next field says how many
122 word-sized pseudos we made. */
125 /* The amount that the stack pointer needs to be adjusted to
126 force alignment for the next argument. */
128 };
130 /* A vector of one char per byte of stack space. A byte if nonzero if
131 the corresponding stack location has been used.
132 This vector is used to prevent a function call within an argument from
133 clobbering any stack already set up. */
136 /* Size of STACK_USAGE_MAP. */
139 /* A bitmap of virtual-incoming stack space. Bit is set if the corresponding
140 stack location's tail call argument has been already stored into the stack.
141 This bitmap is used to prevent sibling call optimization if function tries
142 to use parent's incoming argument slots when they have been already
143 overwritten with tail call arguments. */
146 /* stack_arg_under_construction is nonzero when an argument may be
147 initialized with a constructor call (including a C function that
148 returns a BLKmode struct) and expand_call must take special action
149 to make sure the object being constructed does not overlap the
150 argument list for the constructor call. */
159 CUMULATIVE_ARGS *));
179 CUMULATIVE_ARGS *,
199 static int combine_pending_stack_adjustment_and_call
203 #ifdef REG_PARM_STACK_SPACE
206 #endif
207 \f
208 /* If WHICH is 1, return 1 if EXP contains a call to the built-in function
209 `alloca'.
211 If WHICH is 0, return 1 if EXP contains a call to any function.
212 Actually, we only need return 1 if evaluating EXP would require pushing
213 arguments on the stack, but that is too difficult to compute, so we just
214 assume any function call might require the stack. */
218 static int
220 tree exp;
222 {
229 }
231 /* Recursive function to do the work of above function. */
233 static int
235 tree exp;
237 {
243 /* If this code is language-specific, we don't know what it will do. */
248 {
254 && (TYPE_RETURNS_STACK_DEPRESSED
268 {
269 tree tem;
274 }
284 calls_function_save_exprs);
289 {
290 tree local;
291 tree subblock;
299 subblock;
303 }
314 }
316 /* Only expressions, references, and blocks can contain calls. */
326 }
327 \f
328 /* Force FUNEXP into a form suitable for the address of a CALL,
329 and return that as an rtx. Also load the static chain register
330 if FNDECL is a nested function.
332 CALL_FUSAGE points to a variable holding the prospective
333 CALL_INSN_FUNCTION_USAGE information. */
335 rtx
337 rtx funexp;
338 tree fndecl;
342 {
348 /* Get possible static chain value for nested function in C. */
351 /* Make a valid memory address and copy constants thru pseudo-regs,
352 but not for a constant address if -fno-function-cse. */
354 /* If we are using registers for parameters, force the
355 function address into a register now. */
360 {
361 #ifndef NO_FUNCTION_CSE
363 #ifdef NO_RECURSIVE_FUNCTION_CSE
365 #endif
367 #endif
368 }
371 {
376 }
379 }
381 /* Generate instructions to call function FUNEXP,
382 and optionally pop the results.
383 The CALL_INSN is the first insn generated.
385 FNDECL is the declaration node of the function. This is given to the
386 macro RETURN_POPS_ARGS to determine whether this function pops its own args.
388 FUNTYPE is the data type of the function. This is given to the macro
389 RETURN_POPS_ARGS to determine whether this function pops its own args.
390 We used to allow an identifier for library functions, but that doesn't
391 work when the return type is an aggregate type and the calling convention
392 says that the pointer to this aggregate is to be popped by the callee.
394 STACK_SIZE is the number of bytes of arguments on the stack,
395 ROUNDED_STACK_SIZE is that number rounded up to
396 PREFERRED_STACK_BOUNDARY; zero if the size is variable. This is
397 both to put into the call insn and to generate explicit popping
398 code if necessary.
400 STRUCT_VALUE_SIZE is the number of bytes wanted in a structure value.
401 It is zero if this call doesn't want a structure value.
403 NEXT_ARG_REG is the rtx that results from executing
404 FUNCTION_ARG (args_so_far, VOIDmode, void_type_node, 1)
405 just after all the args have had their registers assigned.
406 This could be whatever you like, but normally it is the first
407 arg-register beyond those used for args in this call,
408 or 0 if all the arg-registers are used in this call.
409 It is passed on to `gen_call' so you can put this info in the call insn.
411 VALREG is a hard register in which a value is returned,
412 or 0 if the call does not return a value.
414 OLD_INHIBIT_DEFER_POP is the value that `inhibit_defer_pop' had before
415 the args to this call were processed.
416 We restore `inhibit_defer_pop' to that value.
418 CALL_FUSAGE is either empty or an EXPR_LIST of USE expressions that
419 denote registers used by the called function. */
421 static void
425 rtx funexp;
426 tree fndecl ATTRIBUTE_UNUSED;
427 tree funtype ATTRIBUTE_UNUSED;
428 HOST_WIDE_INT stack_size ATTRIBUTE_UNUSED;
429 HOST_WIDE_INT rounded_stack_size;
430 HOST_WIDE_INT struct_value_size ATTRIBUTE_UNUSED;
431 rtx next_arg_reg ATTRIBUTE_UNUSED;
432 rtx valreg;
434 rtx call_fusage;
437 {
439 rtx call_insn;
442 #if defined (HAVE_call) && defined (HAVE_call_value)
443 rtx struct_value_size_rtx;
445 #endif
447 #ifdef CALL_POPS_ARGS
449 #endif
451 /* Ensure address is valid. SYMBOL_REF is already valid, so no need,
452 and we don't want to load it into a register as an optimization,
453 because prepare_call_address already did it if it should be done. */
457 #if defined (HAVE_sibcall_pop) && defined (HAVE_sibcall_value_pop)
461 {
463 rtx pat;
465 /* If this subroutine pops its own args, record that in the call insn
466 if possible, for the sake of frame pointer elimination. */
472 n_pop);
473 else
479 }
480 else
481 #endif
483 #if defined (HAVE_call_pop) && defined (HAVE_call_value_pop)
484 /* If the target has "call" or "call_value" insns, then prefer them
485 if no arguments are actually popped. If the target does not have
486 "call" or "call_value" insns, then we must use the popping versions
487 even if the call has no arguments to pop. */
488 #if defined (HAVE_call) && defined (HAVE_call_value)
491 #else
493 #endif
494 {
496 rtx pat;
498 /* If this subroutine pops its own args, record that in the call insn
499 if possible, for the sake of frame pointer elimination. */
505 else
511 }
512 else
513 #endif
515 #if defined (HAVE_sibcall) && defined (HAVE_sibcall_value)
518 {
522 rounded_stack_size_rtx,
524 else
527 struct_value_size_rtx));
528 }
529 else
530 #endif
532 #if defined (HAVE_call) && defined (HAVE_call_value)
534 {
539 NULL_RTX));
540 else
543 struct_value_size_rtx));
544 }
545 else
546 #endif
549 /* Find the CALL insn we just emitted. */
553 ;
558 /* Mark memory as used for "pure" function call. */
560 call_fusage
561 = gen_rtx_EXPR_LIST
565 call_fusage);
567 /* Put the register usage information on the CALL. If there is already
568 some usage information, put ours at the end. */
570 {
571 rtx link;
575 ;
578 }
579 else
582 /* If this is a const call, then set the insn's unchanging bit. */
586 /* If this call can't throw, attach a REG_EH_REGION reg note to that
587 effect. */
600 {
604 }
608 /* Restore this now, so that we do defer pops for this call's args
609 if the context of the call as a whole permits. */
613 {
622 }
625 {
626 /* If returning from the subroutine does not automatically pop the args,
627 we need an instruction to pop them sooner or later.
628 Perhaps do it now; perhaps just record how much space to pop later.
630 If returning from the subroutine does pop the args, indicate that the
631 stack pointer will be changed. */
634 {
636 /* Just pretend we did the pop. */
641 else
643 }
644 }
645 /* When we accumulate outgoing args, we must avoid any stack manipulations.
646 Restore the stack pointer to its original value now. Usually
647 ACCUMULATE_OUTGOING_ARGS targets don't get here, but there are exceptions.
648 On i386 ACCUMULATE_OUTGOING_ARGS can be enabled on demand, and
649 popping variants of functions exist as well.
651 ??? We may optimize similar to defer_pop above, but it is
652 probably not worthwhile.
654 ??? It will be worthwhile to enable combine_stack_adjustments even for
655 such machines. */
658 }
660 /* Determine if the function identified by NAME and FNDECL is one with
661 special properties we wish to know about.
663 For example, if the function might return more than one time (setjmp), then
664 set RETURNS_TWICE to a nonzero value.
666 Similarly set LONGJMP for if the function is in the longjmp family.
668 Set MALLOC for any of the standard memory allocation functions which
669 allocate from the heap.
671 Set MAY_BE_ALLOCA for any memory allocation function that might allocate
672 space from the stack such as alloca. */
674 static int
676 tree fndecl;
678 {
682 /* Exclude functions not at the file scope, or not `extern',
683 since they are not the magic functions we would otherwise
684 think they are. */
686 {
690 /* We assume that alloca will always be called by name. It
691 makes no sense to pass it as a pointer-to-function to
692 anything that does not understand its behavior. */
701 /* Disregard prefix _, __ or __x. */
703 {
708 else
710 }
713 {
726 }
739 /* Linux specific: __clone. check NAME to insist on the
740 leading underscores, to avoid polluting the ISO / POSIX
741 namespace. */
751 /* Do not add any more malloc-like functions to this list,
752 instead mark them as malloc functions using the malloc attribute.
753 Note, realloc is not suitable for attribute malloc since
754 it may return the same address across multiple calls.
755 C++ operator new is not suitable because it is not required
756 to return a unique pointer; indeed, the standard placement new
757 just returns its argument. */
763 }
765 }
767 /* Return nonzero when tree represent call to longjmp. */
769 int
771 tree fndecl;
772 {
774 }
776 /* Return true when exp contains alloca call. */
777 bool
779 tree exp;
780 {
789 }
791 /* Detect flags (function attributes) from the function decl or type node. */
793 int
795 tree exp;
796 {
801 {
806 {
811 }
813 /* The function exp may have the `malloc' attribute. */
817 /* The function exp may have the `pure' attribute. */
823 }
831 /* Mark if the function returns with the stack pointer depressed. We
832 cannot consider it pure or constant in that case. */
834 {
837 }
840 }
842 /* Precompute all register parameters as described by ARGS, storing values
843 into fields within the ARGS array.
845 NUM_ACTUALS indicates the total number elements in the ARGS array.
847 Set REG_PARM_SEEN if we encounter a register parameter. */
849 static void
854 {
861 {
865 {
872 /* ANSI doesn't require a sequence point here,
873 but PCC has one, so this will avoid some problems. */
875 }
877 /* If the value is a non-legitimate constant, force it into a
878 pseudo now. TLS symbols sometimes need a call to resolve. */
883 /* If we are to promote the function arg to a wider mode,
884 do it now. */
892 /* If the value is expensive, and we are inside an appropriately
893 short loop, put the value into a pseudo and then put the pseudo
894 into the hard reg.
896 For small register classes, also do this if this call uses
897 register parameters. This is to avoid reload conflicts while
898 loading the parameters registers. */
908 }
909 }
911 #ifdef REG_PARM_STACK_SPACE
913 /* The argument list is the property of the called routine and it
914 may clobber it. If the fixed area has been used for previous
915 parameters, we must save and restore it. */
917 static rtx
921 rtx argblock;
924 {
928 /* Compute the boundary of the area that needs to be saved, if any. */
930 #ifdef ARGS_GROW_DOWNWARD
932 #endif
938 {
942 rtx stack_area;
943 rtx save_area;
946 ;
954 /* If we don't have the required alignment, must do this
955 in BLKmode. */
960 #ifdef ARGS_GROW_DOWNWARD
962 #else
964 #endif
968 delta)));
972 {
976 }
977 else
978 {
981 }
984 }
987 }
989 static void
991 rtx save_area;
992 rtx argblock;
995 {
998 rtx stack_area;
1000 #ifdef ARGS_GROW_DOWNWARD
1002 #else
1004 #endif
1012 else
1015 BLOCK_OP_CALL_PARM);
1016 }
1019 /* If any elements in ARGS refer to parameters that are to be passed in
1020 registers, but not in memory, and whose alignment does not permit a
1021 direct copy into registers. Copy the values into a group of pseudos
1022 which we will later copy into the appropriate hard registers.
1024 Pseudos for each unaligned argument will be stored into the array
1025 args[argnum].aligned_regs. The caller is responsible for deallocating
1026 the aligned_regs array if it is nonzero. */
1028 static void
1032 {
1040 {
1051 /* Structures smaller than a word are aligned to the least
1052 significant byte (to the right). On a BYTES_BIG_ENDIAN machine,
1053 this means we must skip the empty high order bytes when
1054 calculating the bit offset. */
1060 {
1067 /* There is no need to restrict this code to loading items
1068 in TYPE_ALIGN sized hunks. The bitfield instructions can
1069 load up entire word sized registers efficiently.
1071 ??? This may not be needed anymore.
1072 We use to emit a clobber here but that doesn't let later
1073 passes optimize the instructions we emit. By storing 0 into
1074 the register later passes know the first AND to zero out the
1075 bitfield being set in the register is unnecessary. The store
1076 of 0 will be deleted as will at least the first AND. */
1084 BITS_PER_WORD),
1085 BITS_PER_WORD);
1086 }
1087 }
1088 }
1090 /* Fill in ARGS_SIZE and ARGS array based on the parameters found in
1091 ACTPARMS.
1093 NUM_ACTUALS is the total number of parameters.
1095 N_NAMED_ARGS is the total number of named arguments.
1097 FNDECL is the tree code for the target of this call (if known)
1099 ARGS_SO_FAR holds state needed by the target to know where to place
1100 the next argument.
1102 REG_PARM_STACK_SPACE is the number of bytes of stack space reserved
1103 for arguments which are passed in registers.
1105 OLD_STACK_LEVEL is a pointer to an rtx which olds the old stack level
1106 and may be modified by this routine.
1108 OLD_PENDING_ADJ, MUST_PREALLOCATE and FLAGS are pointers to integer
1109 flags which may may be modified by this routine. */
1111 static void
1116 ecf_flags)
1121 tree actparms;
1122 tree fndecl;
1129 {
1130 /* 1 if scanning parms front to back, -1 if scanning back to front. */
1133 /* Count arg position in order args appear. */
1138 tree p;
1143 /* In this loop, we consider args in the order they are written.
1144 We fill up ARGS from the front or from the back if necessary
1145 so that in any case the first arg to be pushed ends up at the front. */
1148 {
1150 /* In this case, must reverse order of args
1151 so that we compute and push the last arg first. */
1152 }
1153 else
1154 {
1156 }
1158 /* I counts args in order (to be) pushed; ARGPOS counts in order written. */
1160 {
1167 /* Replace erroneous argument with constant zero. */
1171 /* If TYPE is a transparent union, pass things the way we would
1172 pass the first field of the union. We have already verified that
1173 the modes are the same. */
1177 /* Decide where to pass this arg.
1179 args[i].reg is nonzero if all or part is passed in registers.
1181 args[i].partial is nonzero if part but not all is passed in registers,
1182 and the exact value says how many words are passed in registers.
1184 args[i].pass_on_stack is nonzero if the argument must at least be
1185 computed on the stack. It may then be loaded back into registers
1186 if args[i].reg is nonzero.
1188 These decisions are driven by the FUNCTION_... macros and must agree
1189 with those made by function.c. */
1191 /* See if this argument should be passed by invisible reference. */
1195 #ifdef FUNCTION_ARG_PASS_BY_REFERENCE
1198 #endif
1199 )
1200 {
1201 /* If we're compiling a thunk, pass through invisible
1202 references instead of making a copy. */
1204 #ifdef FUNCTION_ARG_CALLEE_COPIES
1207 /* If it's in a register, we must make a copy of it too. */
1208 /* ??? Is this a sufficient test? Is there a better one? */
1212 #endif
1213 )
1214 {
1215 /* C++ uses a TARGET_EXPR to indicate that we want to make a
1216 new object from the argument. If we are passing by
1217 invisible reference, the callee will do that for us, so we
1218 can strip off the TARGET_EXPR. This is not always safe,
1219 but it is safe in the only case where this is a useful
1220 optimization; namely, when the argument is a plain object.
1221 In that case, the frontend is just asking the backend to
1222 make a bitwise copy of the argument. */
1233 }
1235 {
1236 /* In the V3 C++ ABI, parameters are destroyed in the caller.
1237 We implement this by passing the address of the temporary
1238 rather than expanding it into another allocated slot. */
1243 }
1244 else
1245 {
1246 /* We make a copy of the object and pass the address to the
1247 function being called. */
1248 rtx copy;
1254 STACK_CHECK_MAX_VAR_SIZE))))
1255 {
1256 /* This is a variable-sized object. Make space on the stack
1257 for it. */
1261 {
1265 }
1268 allocate_dynamic_stack_space
1271 }
1272 else
1282 }
1283 }
1288 #ifdef PROMOTE_FUNCTION_ARGS
1290 #endif
1297 #ifdef FUNCTION_INCOMING_ARG
1298 /* If this is a sibling call and the machine has register windows, the
1299 register window has to be unwinded before calling the routine, so
1300 arguments have to go into the incoming registers. */
1303 #else
1305 #endif
1307 #ifdef FUNCTION_ARG_PARTIAL_NREGS
1312 #endif
1316 /* If FUNCTION_ARG returned a (parallel [(expr_list (nil) ...) ...]),
1317 it means that we are to pass this arg in the register(s) designated
1318 by the PARALLEL, but also to pass it in the stack. */
1323 /* If this is an addressable type, we must preallocate the stack
1324 since we must evaluate the object into its final location.
1326 If this is to be passed in both registers and the stack, it is simpler
1327 to preallocate. */
1332 /* If this is an addressable type, we cannot pre-evaluate it. Thus,
1333 we cannot consider this function call constant. */
1337 /* Compute the stack-size of this argument. */
1342 #ifdef STACK_PARMS_IN_REG_PARM_AREA
1344 #else
1346 #endif
1350 #ifndef ARGS_GROW_DOWNWARD
1352 #endif
1356 /* If a part of the arg was put into registers,
1357 don't include that part in the amount pushed. */
1363 /* Update ARGS_SIZE, the total stack space for args so far. */
1367 {
1369 }
1371 /* Since the slot offset points to the bottom of the slot,
1372 we must record it after incrementing if the args grow down. */
1373 #ifdef ARGS_GROW_DOWNWARD
1379 #endif
1381 /* Increment ARGS_SO_FAR, which has info about which arg-registers
1382 have been used, etc. */
1386 }
1387 }
1389 /* Update ARGS_SIZE to contain the total size for the argument block.
1390 Return the original constant component of the argument block's size.
1392 REG_PARM_STACK_SPACE holds the number of bytes of stack space reserved
1393 for arguments passed in registers. */
1395 static int
1397 preferred_stack_boundary)
1401 {
1404 /* For accumulate outgoing args mode we don't need to align, since the frame
1405 will be already aligned. Align to STACK_BOUNDARY in order to prevent
1406 backends from generating misaligned frame sizes. */
1410 /* Compute the actual size of the argument block required. The variable
1411 and constant sizes must be combined, the size may have to be rounded,
1412 and there may be a minimum required size. */
1415 {
1421 {
1422 /* We don't handle this case yet. To handle it correctly we have
1423 to add the delta, round and subtract the delta.
1424 Currently no machine description requires this support. */
1428 }
1431 {
1432 args_size->var
1436 #ifndef OUTGOING_REG_PARM_STACK_SPACE
1437 /* The area corresponding to register parameters is not to count in
1438 the size of the block we need. So make the adjustment. */
1439 args_size->var
1442 #endif
1443 }
1444 }
1445 else
1446 {
1451 + stack_pointer_delta
1453 / preferred_stack_boundary
1458 reg_parm_stack_space);
1460 #ifdef MAYBE_REG_PARM_STACK_SPACE
1463 #endif
1465 #ifndef OUTGOING_REG_PARM_STACK_SPACE
1467 #endif
1468 }
1470 }
1472 /* Precompute parameters as needed for a function call.
1474 FLAGS is mask of ECF_* constants.
1476 NUM_ACTUALS is the number of arguments.
1478 ARGS is an array containing information for each argument; this
1479 routine fills in the INITIAL_VALUE and VALUE fields for each
1480 precomputed argument. */
1482 static void
1487 {
1490 /* If this function call is cse'able, precompute all the parameters.
1491 Note that if the parameter is constructed into a temporary, this will
1492 cause an additional copy because the parameter will be constructed
1493 into a temporary location and then copied into the outgoing arguments.
1494 If a parameter contains a call to alloca and this function uses the
1495 stack, precompute the parameter. */
1497 /* If we preallocated the stack space, and some arguments must be passed
1498 on the stack, then we must precompute any parameter which contains a
1499 function call which will store arguments on the stack.
1500 Otherwise, evaluating the parameter may clobber previous parameters
1501 which have already been stored into the stack. (we have code to avoid
1502 such case by saving the outgoing stack arguments, but it results in
1503 worse code) */
1508 {
1511 /* If this is an addressable type, we cannot pre-evaluate it. */
1518 /* ANSI doesn't require a sequence point here,
1519 but PCC has one, so this will avoid some problems. */
1527 {
1531 #ifdef PROMOTE_FOR_CALL_ONLY
1532 /* CSE will replace this only if it contains args[i].value
1533 pseudo, so convert it down to the declared mode using
1534 a SUBREG. */
1537 {
1543 }
1544 #endif
1545 }
1546 }
1547 }
1549 /* Given the current state of MUST_PREALLOCATE and information about
1550 arguments to a function call in NUM_ACTUALS, ARGS and ARGS_SIZE,
1551 compute and return the final value for MUST_PREALLOCATE. */
1553 static int
1559 {
1560 /* See if we have or want to preallocate stack space.
1562 If we would have to push a partially-in-regs parm
1563 before other stack parms, preallocate stack space instead.
1565 If the size of some parm is not a multiple of the required stack
1566 alignment, we must preallocate.
1568 If the total size of arguments that would otherwise create a copy in
1569 a temporary (such as a CALL) is more than half the total argument list
1570 size, preallocation is faster.
1572 Another reason to preallocate is if we have a machine (like the m88k)
1573 where stack alignment is required to be maintained between every
1574 pair of insns, not just when the call is made. However, we assume here
1575 that such machines either do not have push insns (and hence preallocation
1576 would occur anyway) or the problem is taken care of with
1577 PUSH_ROUNDING. */
1580 {
1586 {
1597 copy_to_evaluate_size
1599 }
1604 }
1606 }
1608 /* If we preallocated stack space, compute the address of each argument
1609 and store it into the ARGS array.
1611 We need not ensure it is a valid memory address here; it will be
1612 validized when it is used.
1614 ARGBLOCK is an rtx for the address of the outgoing arguments. */
1616 static void
1619 rtx argblock;
1621 {
1623 {
1631 {
1634 rtx addr;
1636 /* Skip this parm if it will not be passed on the stack. */
1642 else
1653 else
1662 /* Function incoming arguments may overlap with sibling call
1663 outgoing arguments and we cannot allow reordering of reads
1664 from function arguments with stores to outgoing arguments
1665 of sibling calls. */
1668 }
1669 }
1670 }
1672 /* Given a FNDECL and EXP, return an rtx suitable for use as a target address
1673 in a call instruction.
1675 FNDECL is the tree node for the target function. For an indirect call
1676 FNDECL will be NULL_TREE.
1678 ADDR is the operand 0 of CALL_EXPR for this call. */
1680 static rtx
1682 tree fndecl;
1683 tree addr;
1684 {
1685 rtx funexp;
1687 /* Get the function to call, in the form of RTL. */
1689 {
1690 /* If this is the first use of the function, see if we need to
1691 make an external definition for it. */
1693 {
1696 }
1698 /* Get a SYMBOL_REF rtx for the function address. */
1700 }
1701 else
1702 /* Generate an rtx (probably a pseudo-register) for the address. */
1703 {
1708 }
1710 }
1712 /* Do the register loads required for any wholly-register parms or any
1713 parms which are passed both on the stack and in a register. Their
1714 expressions were already evaluated.
1716 Mark all register-parms as living through the call, putting these USE
1717 insns in the CALL_INSN_FUNCTION_USAGE field.
1719 When IS_SIBCALL, perform the check_sibcall_overlap_argument_overlap
1720 checking, setting *SIBCALL_FAILURE if appropriate. */
1722 static void
1731 {
1734 #ifdef LOAD_ARGS_REVERSED
1736 #else
1738 #endif
1739 {
1746 {
1748 /* Set to non-negative if must move a word at a time, even if just
1749 one word (e.g, partial == 1 && mode == DFmode). Set to -1 if
1750 we just use a normal move insn. This value can be zero if the
1751 argument is a zero size structure with no fields. */
1758 /* Handle calls that pass values in multiple non-contiguous
1759 locations. The Irix 6 ABI has examples of this. */
1765 /* If simple case, just do move. If normal partial, store_one_arg
1766 has already loaded the register for us. In all other cases,
1767 load the register(s) from memory. */
1772 /* If we have pre-computed the values to put in the registers in
1773 the case of non-aligned structures, copy them in now. */
1785 /* When a parameter is a block, and perhaps in other cases, it is
1786 possible that it did a load from an argument slot that was
1787 already clobbered. */
1792 /* Handle calls that pass values in multiple non-contiguous
1793 locations. The Irix 6 ABI has examples of this. */
1798 else
1800 }
1801 }
1802 }
1804 /* Try to integrate function. See expand_inline_function for documentation
1805 about the parameters. */
1807 static rtx
1809 tree fndecl;
1810 tree actparms;
1811 rtx target;
1813 tree type;
1814 rtx structure_value_addr;
1815 {
1816 rtx temp;
1817 rtx before_call;
1822 #ifdef REG_PARM_STACK_SPACE
1823 #ifdef MAYBE_REG_PARM_STACK_SPACE
1825 #else
1827 #endif
1828 #endif
1836 structure_value_addr);
1840 /* If inlining succeeded, return. */
1842 {
1844 {
1845 /* If the outgoing argument list must be preserved, push
1846 the stack before executing the inlined function if it
1847 makes any calls. */
1853 ;
1856 {
1857 rtx first_insn
1861 /* Look for a call in the inline function code.
1862 If DECL_SAVED_INSNS (fndecl)->outgoing_args_size is
1863 nonzero then there is a call and it is not necessary
1864 to scan the insns. */
1872 {
1873 /* Reserve enough stack space so that the largest
1874 argument list of any function call in the inline
1875 function does not overlap the argument list being
1876 evaluated. This is usually an overestimate because
1877 allocate_dynamic_stack_space reserves space for an
1878 outgoing argument list in addition to the requested
1879 space, but there is no way to ask for stack space such
1880 that an argument list of a certain length can be
1881 safely constructed.
1883 Add the stack space reserved for register arguments, if
1884 any, in the inline function. What is really needed is the
1885 largest value of reg_parm_stack_space in the inline
1886 function, but that is not available. Using the current
1887 value of reg_parm_stack_space is wrong, but gives
1888 correct results on all supported machines. */
1901 }
1902 }
1903 }
1905 /* If the result is equivalent to TARGET, return TARGET to simplify
1906 checks in store_expr. They can be equivalent but not equal in the
1907 case of a function that returns BLKmode. */
1911 }
1913 /* If inlining failed, mark FNDECL as needing to be compiled
1914 separately after all. If function was declared inline,
1915 give a warning. */
1918 {
1921 }
1924 }
1926 /* We need to pop PENDING_STACK_ADJUST bytes. But, if the arguments
1927 wouldn't fill up an even multiple of PREFERRED_UNIT_STACK_BOUNDARY
1928 bytes, then we would need to push some additional bytes to pad the
1929 arguments. So, we compute an adjust to the stack pointer for an
1930 amount that will leave the stack under-aligned by UNADJUSTED_ARGS_SIZE
1931 bytes. Then, when the arguments are pushed the stack will be perfectly
1932 aligned. ARGS_SIZE->CONSTANT is set to the number of bytes that should
1933 be popped after the call. Returns the adjustment. */
1935 static int
1937 args_size,
1938 preferred_unit_stack_boundary)
1942 {
1943 /* The number of bytes to pop so that the stack will be
1944 under-aligned by UNADJUSTED_ARGS_SIZE bytes. */
1945 HOST_WIDE_INT adjustment;
1946 /* The alignment of the stack after the arguments are pushed, if we
1947 just pushed the arguments without adjust the stack here. */
1948 HOST_WIDE_INT unadjusted_alignment;
1950 unadjusted_alignment
1954 /* We want to get rid of as many of the PENDING_STACK_ADJUST bytes
1955 as possible -- leaving just enough left to cancel out the
1956 UNADJUSTED_ALIGNMENT. In other words, we want to ensure that the
1957 PENDING_STACK_ADJUST is non-negative, and congruent to
1958 -UNADJUSTED_ALIGNMENT modulo the PREFERRED_UNIT_STACK_BOUNDARY. */
1960 /* Begin by trying to pop all the bytes. */
1961 unadjusted_alignment
1962 = (unadjusted_alignment
1965 /* Push enough additional bytes that the stack will be aligned
1966 after the arguments are pushed. */
1968 {
1971 else
1973 }
1975 /* Now, sets ARGS_SIZE->CONSTANT so that we pop the right number of
1976 bytes after the call. The right number is the entire
1977 PENDING_STACK_ADJUST less our ADJUSTMENT plus the amount required
1978 by the arguments in the first place. */
1979 args_size->constant
1983 }
1985 /* Scan X expression if it does not dereference any argument slots
1986 we already clobbered by tail call arguments (as noted in stored_args_map
1987 bitmap).
1988 Return nonzero if X expression dereferences such argument slots,
1989 zero otherwise. */
1991 static int
1993 rtx x;
1994 {
1995 RTX_CODE code;
2006 {
2011 current_function_internal_arg_pointer
2014 else
2017 #ifdef ARGS_GROW_DOWNWARD
2019 #endif
2027 }
2029 /* Scan all subexpressions. */
2032 {
2034 {
2037 }
2039 {
2043 }
2044 }
2046 }
2048 /* Scan sequence after INSN if it does not dereference any argument slots
2049 we already clobbered by tail call arguments (as noted in stored_args_map
2050 bitmap). If MARK_STORED_ARGS_MAP, add stack slots for ARG to
2051 stored_args_map bitmap afterwards (when ARG is a register MARK_STORED_ARGS_MAP
2052 should be 0). Return nonzero if sequence after INSN dereferences such argument
2053 slots, zero otherwise. */
2055 static int
2057 rtx insn;
2060 {
2065 else
2074 {
2075 #ifdef ARGS_GROW_DOWNWARD
2077 #else
2079 #endif
2083 }
2085 }
2087 static tree
2089 tree t;
2090 {
2092 {
2101 {
2107 }
2112 }
2114 }
2116 /* Generate all the code for a function call
2117 and return an rtx for its value.
2118 Store the value in TARGET (specified as an rtx) if convenient.
2119 If the value is stored in TARGET then TARGET is returned.
2120 If IGNORE is nonzero, then we ignore the value of the function call. */
2122 rtx
2124 tree exp;
2125 rtx target;
2127 {
2128 /* Nonzero if we are currently expanding a call. */
2131 /* List of actual parameters. */
2133 /* RTX for the function to be called. */
2134 rtx funexp;
2135 /* Sequence of insns to perform a tail recursive "call". */
2137 /* Sequence of insns to perform a normal "call". */
2139 /* Sequence of insns to perform a tail recursive "call". */
2141 /* Data type of the function. */
2142 tree funtype;
2143 /* Declaration of the function being called,
2144 or 0 if the function is computed (not known by name). */
2146 rtx insn;
2151 /* Register in which non-BLKmode value will be returned,
2152 or 0 if no value or if value is BLKmode. */
2153 rtx valreg;
2154 /* Address where we should return a BLKmode value;
2155 0 if value not BLKmode. */
2157 /* Nonzero if that address is being passed by treating it as
2158 an extra, implicit first parameter. Otherwise,
2159 it is passed by being copied directly into struct_value_rtx. */
2161 /* Size of aggregate value wanted, or zero if none wanted
2162 or if we are using the non-reentrant PCC calling convention
2163 or expecting the value in registers. */
2165 /* Nonzero if called function returns an aggregate in memory PCC style,
2166 by returning the address of where to find it. */
2169 /* Number of actual parameters in this call, including struct value addr. */
2171 /* Number of named args. Args after this are anonymous ones
2172 and they must all go on the stack. */
2175 /* Vector of information about each argument.
2176 Arguments are numbered in the order they will be pushed,
2177 not the order they are written. */
2180 /* Total size in bytes of all the stack-parms scanned so far. */
2183 /* Size of arguments before any adjustments (such as rounding). */
2185 /* Data on reg parms scanned so far. */
2186 CUMULATIVE_ARGS args_so_far;
2187 /* Nonzero if a reg parm has been scanned. */
2189 /* Nonzero if this is an indirect function call. */
2191 /* Nonzero if we must avoid push-insns in the args for this call.
2192 If stack space is allocated for register parameters, but not by the
2193 caller, then it is preallocated in the fixed part of the stack frame.
2194 So the entire argument block must then be preallocated (i.e., we
2195 ignore PUSH_ROUNDING in that case). */
2199 /* Size of the stack reserved for parameter registers. */
2202 /* Address of space preallocated for stack parms
2203 (on machines that lack push insns), or 0 if space not preallocated. */
2206 /* Mask of ECF_ flags. */
2208 /* Nonzero if this is a call to an inline function. */
2210 #ifdef REG_PARM_STACK_SPACE
2211 /* Define the boundary of the register parm stack space that needs to be
2212 saved, if any. */
2215 #endif
2225 rtx call_fusage;
2229 /* The alignment of the stack, in bits. */
2230 HOST_WIDE_INT preferred_stack_boundary;
2231 /* The alignment of the stack, in bytes. */
2232 HOST_WIDE_INT preferred_unit_stack_boundary;
2234 /* See if this is "nothrow" function call. */
2238 /* See if we can find a DECL-node for the actual function.
2239 As a result, decide whether this is a call to an integrable function. */
2243 {
2251 {
2252 /* In case this function later becomes inlinable,
2253 record that there was already a non-inline call to it.
2255 Use abstraction instead of setting TREE_ADDRESSABLE
2256 directly. */
2259 {
2262 }
2264 }
2267 }
2269 /* If we don't have specific function to call, see if we have a
2270 attributes set in the type. */
2271 else
2274 #ifdef REG_PARM_STACK_SPACE
2275 #ifdef MAYBE_REG_PARM_STACK_SPACE
2277 #else
2279 #endif
2280 #endif
2282 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2285 #endif
2287 /* Warn if this value is an aggregate type,
2288 regardless of which calling convention we are using for it. */
2292 /* Set up a place to return a structure. */
2294 /* Cater to broken compilers. */
2296 {
2297 /* This call returns a big structure. */
2300 #ifdef PCC_STATIC_STRUCT_RETURN
2301 {
2303 /* Easier than making that case work right. */
2305 {
2306 /* In case this is a static function, note that it has been
2307 used. */
2311 }
2312 }
2314 {
2318 {
2319 /* The structure value address arg is already in actparms.
2320 Pull it out. It might be nice to just leave it there, but
2321 we need to set structure_value_addr. */
2326 }
2329 else
2330 {
2331 /* For variable-sized objects, we must be called with a target
2332 specified. If we were to allocate space on the stack here,
2333 we would have no way of knowing when to free it. */
2339 }
2340 }
2342 }
2344 /* If called function is inline, try to integrate it. */
2347 {
2350 structure_value_addr);
2353 }
2355 /* Figure out the amount to which the stack should be aligned. */
2358 {
2362 }
2364 /* Operand 0 is a pointer-to-function; get the type of the function. */
2370 /* See if this is a call to a function that can return more than once
2371 or a call to longjmp or malloc. */
2377 /* If struct_value_rtx is 0, it means pass the address
2378 as if it were an extra parameter. */
2380 {
2381 /* If structure_value_addr is a REG other than
2382 virtual_outgoing_args_rtx, we can use always use it. If it
2383 is not a REG, we must always copy it into a register.
2384 If it is virtual_outgoing_args_rtx, we must copy it to another
2385 register in some cases. */
2387 || (ACCUMULATE_OUTGOING_ARGS
2388 && stack_arg_under_construction
2393 actparms
2396 temp),
2397 actparms);
2399 }
2401 /* Count the arguments and set NUM_ACTUALS. */
2403 num_actuals++;
2405 /* Compute number of named args.
2406 Normally, don't include the last named arg if anonymous args follow.
2407 We do include the last named arg if STRICT_ARGUMENT_NAMING is nonzero.
2408 (If no anonymous args follow, the result of list_length is actually
2409 one too large. This is harmless.)
2411 If PRETEND_OUTGOING_VARARGS_NAMED is set and STRICT_ARGUMENT_NAMING is
2412 zero, this machine will be able to place unnamed args that were
2413 passed in registers into the stack. So treat all args as named.
2414 This allows the insns emitting for a specific argument list to be
2415 independent of the function declaration.
2417 If PRETEND_OUTGOING_VARARGS_NAMED is not set, we do not have any
2418 reliable way to pass unnamed args in registers, so we must force
2419 them into memory. */
2424 n_named_args
2426 /* Don't include the last named arg. */
2428 /* Count the struct value address, if it is passed as a parm. */
2430 else
2431 /* If we know nothing, treat all args as named. */
2434 /* Start updating where the next arg would go.
2436 On some machines (such as the PA) indirect calls have a different
2437 calling convention than normal calls. The last argument in
2438 INIT_CUMULATIVE_ARGS tells the backend if this is an indirect call
2439 or not. */
2442 /* Make a vector to hold all the information about each arg. */
2446 /* Build up entries in the ARGS array, compute the size of the
2447 arguments into ARGS_SIZE, etc. */
2455 {
2456 /* If this function requires a variable-sized argument list, don't
2457 try to make a cse'able block for this call. We may be able to
2458 do this eventually, but it is too complicated to keep track of
2459 what insns go in the cse'able block and which don't. */
2463 }
2465 /* Now make final decision about preallocating stack space. */
2470 /* If the structure value address will reference the stack pointer, we
2471 must stabilize it. We don't need to do this if we know that we are
2472 not going to adjust the stack pointer in processing this call. */
2477 structure_value_addr))
2482 /* Tail calls can make things harder to debug, and we're traditionally
2483 pushed these optimizations into -O2. Don't try if we're already
2484 expanding a call, as that means we're an argument. Don't try if
2485 there's cleanups, as we know there's code to follow the call.
2487 If rtx_equal_function_value_matters is false, that means we've
2488 finished with regular parsing. Which means that some of the
2489 machinery we use to generate tail-calls is no longer in place.
2490 This is most often true of sjlj-exceptions, which we couldn't
2491 tail-call to anyway. */
2494 || !flag_optimize_sibling_calls
2495 || !rtx_equal_function_value_matters
2500 /* Tail recursion fails, when we are not dealing with recursive calls. */
2506 /* Rest of purposes for tail call optimizations to fail. */
2508 #ifdef HAVE_sibcall_epilogue
2509 !HAVE_sibcall_epilogue
2510 #else
2511 1
2512 #endif
2513 || !try_tail_call
2514 /* Doing sibling call optimization needs some work, since
2515 structure_value_addr can be allocated on the stack.
2516 It does not seem worth the effort since few optimizable
2517 sibling calls will return a structure. */
2519 /* Check whether the target is able to optimize the call
2520 into a sibcall. */
2522 /* Functions that do not return exactly once may not be sibcall
2523 optimized. */
2526 /* If this function requires more stack slots than the current
2527 function, we cannot change it into a sibling call. */
2529 /* If the callee pops its own arguments, then it must pop exactly
2530 the same number of arguments as the current function. */
2534 current_function_args_size))
2538 {
2541 /* Ok, we're going to give the tail call the old college try.
2542 This means we're going to evaluate the function arguments
2543 up to three times. There are two degrees of badness we can
2544 encounter, those that can be unsaved and those that can't.
2545 (See unsafe_for_reeval commentary for details.)
2547 Generate a new argument list. Pass safe arguments through
2548 unchanged. For the easy badness wrap them in UNSAVE_EXPRs.
2549 For hard badness, evaluate them now and put their resulting
2550 rtx in a temporary VAR_DECL.
2552 initialize_argument_information has ordered the array for the
2553 order to be pushed, and we must remember this when reconstructing
2554 the original argument order. */
2557 {
2561 }
2562 else
2563 {
2567 }
2570 {
2572 /* We need to build actparms for optimize_tail_recursion. We can
2573 safely trash away TREE_PURPOSE, since it is unused by this
2574 function. */
2577 }
2578 /* Do the same for the function address if it is an expression. */
2581 /* Expanding one of those dangerous arguments could have added
2582 cleanups, but otherwise give it a whirl. */
2585 }
2587 /* Generate a tail recursion sequence when calling ourselves. */
2590 {
2591 /* We want to emit any pending stack adjustments before the tail
2592 recursion "call". That way we know any adjustment after the tail
2593 recursion call can be ignored if we indeed use the tail recursion
2594 call expansion. */
2598 /* Emit any queued insns now; otherwise they would end up in
2599 only one of the alternates. */
2602 /* Use a new sequence to hold any RTL we generate. We do not even
2603 know if we will use this RTL yet. The final decision can not be
2604 made until after RTL generation for the entire function is
2605 complete. */
2607 /* If expanding any of the arguments creates cleanups, we can't
2608 do a tailcall. So, we'll need to pop the pending cleanups
2609 list. If, however, all goes well, and there are no cleanups
2610 then the call to expand_start_target_temps will have no
2611 effect. */
2614 {
2617 else
2619 }
2623 /* Restore the original pending stack adjustment for the sibling and
2624 normal call cases below. */
2627 }
2630 {
2631 /* A fork duplicates the profile information, and an exec discards
2632 it. We can't rely on fork/exec to be paired. So write out the
2633 profile information we have gathered so far, and clear it. */
2634 /* ??? When Linux's __clone is called with CLONE_VM set, profiling
2635 is subject to race conditions, just as with multithreaded
2636 programs. */
2639 }
2641 /* Ensure current function's preferred stack boundary is at least
2642 what we need. We don't have to increase alignment for recursive
2643 functions. */
2652 function_call_count++;
2654 /* We want to make two insn chains; one for a sibling call, the other
2655 for a normal call. We will select one of the two chains after
2656 initial RTL generation is complete. */
2658 {
2660 /* We want to emit any pending stack adjustments before the tail
2661 recursion "call". That way we know any adjustment after the tail
2662 recursion call can be ignored if we indeed use the tail recursion
2663 call expansion. */
2666 rtx insns;
2670 {
2671 /* Emit any queued insns now; otherwise they would end up in
2672 only one of the alternates. */
2675 /* State variables we need to save and restore between
2676 iterations. */
2679 }
2682 else
2685 /* Other state variables that we must reinitialize each time
2686 through the loop (that are not initialized by the loop itself). */
2690 /* Start a new sequence for the normal call case.
2692 From this point on, if the sibling call fails, we want to set
2693 sibcall_failure instead of continuing the loop. */
2697 {
2698 /* We know at this point that there are not currently any
2699 pending cleanups. If, however, in the process of evaluating
2700 the arguments we were to create some, we'll need to be
2701 able to get rid of them. */
2703 }
2705 /* Don't let pending stack adjusts add up to too much.
2706 Also, do all pending adjustments now if there is any chance
2707 this might be a call to alloca or if we are expanding a sibling
2708 call sequence or if we are calling a function that is to return
2709 with stack pointer depressed. */
2716 /* When calling a const function, we must pop the stack args right away,
2717 so that the pop is deleted or moved with the call. */
2719 NO_DEFER_POP;
2721 #ifdef FINAL_REG_PARM_STACK_SPACE
2724 #endif
2725 /* Precompute any arguments as needed. */
2729 /* Now we are about to start emitting insns that can be deleted
2730 if a libcall is deleted. */
2735 /* Compute the actual size of the argument block required. The variable
2736 and constant sizes must be combined, the size may have to be rounded,
2737 and there may be a minimum required size. When generating a sibcall
2738 pattern, do not round up, since we'll be re-using whatever space our
2739 caller provided. */
2740 unadjusted_args_size
2748 /* The argument block when performing a sibling call is the
2749 incoming argument block. */
2751 {
2753 argblock
2754 #ifdef STACK_GROWS_DOWNWARD
2756 #else
2758 #endif
2761 }
2763 /* If we have no actual push instructions, or shouldn't use them,
2764 make space for all args right now. */
2766 {
2768 {
2772 /* stack_arg_under_construction says whether a stack arg is
2773 being constructed at the old stack level. Pushing the stack
2774 gets a clean outgoing argument block. */
2777 }
2779 }
2780 else
2781 {
2782 /* Note that we must go through the motions of allocating an argument
2783 block even if the size is zero because we may be storing args
2784 in the area reserved for register arguments, which may be part of
2785 the stack frame. */
2789 /* Store the maximum argument space used. It will be pushed by
2790 the prologue (if ACCUMULATE_OUTGOING_ARGS, or stack overflow
2791 checking). */
2797 {
2799 {
2800 /* Since the stack pointer will never be pushed, it is
2801 possible for the evaluation of a parm to clobber
2802 something we have already written to the stack.
2803 Since most function calls on RISC machines do not use
2804 the stack, this is uncommon, but must work correctly.
2806 Therefore, we save any area of the stack that was already
2807 written and that we are using. Here we set up to do this
2808 by making a new stack usage map from the old one. The
2809 actual save will be done by store_one_arg.
2811 Another approach might be to try to reorder the argument
2812 evaluations to avoid this conflicting stack usage. */
2814 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2815 /* Since we will be writing into the entire argument area,
2816 the map must be allocated for its entire size, not just
2817 the part that is the responsibility of the caller. */
2819 #endif
2821 #ifdef ARGS_GROW_DOWNWARD
2824 #else
2826 needed);
2827 #endif
2828 stack_usage_map
2833 initial_highest_arg_in_use);
2837 (highest_outgoing_arg_in_use
2841 /* The address of the outgoing argument list must not be
2842 copied to a register here, because argblock would be left
2843 pointing to the wrong place after the call to
2844 allocate_dynamic_stack_space below. */
2847 }
2848 else
2849 {
2851 {
2852 /* Try to reuse some or all of the pending_stack_adjust
2853 to get this space. */
2854 needed
2855 = (combine_pending_stack_adjustment_and_call
2858 preferred_unit_stack_boundary));
2860 /* combine_pending_stack_adjustment_and_call computes
2861 an adjustment before the arguments are allocated.
2862 Account for them and see whether or not the stack
2863 needs to go up or down. */
2867 {
2868 /* We're releasing stack space. */
2869 /* ??? We can avoid any adjustment at all if we're
2870 already aligned. FIXME. */
2874 }
2875 else
2876 /* We need to allocate space. We'll do that in
2877 push_block below. */
2879 }
2881 /* Special case this because overhead of `push_block' in
2882 this case is non-trivial. */
2885 else
2888 /* We only really need to call `copy_to_reg' in the case
2889 where push insns are going to be used to pass ARGBLOCK
2890 to a function call in ARGS. In that case, the stack
2891 pointer changes value from the allocation point to the
2892 call point, and hence the value of
2893 VIRTUAL_OUTGOING_ARGS_RTX changes as well. But might
2894 as well always do it. */
2897 /* The save/restore code in store_one_arg handles all
2898 cases except one: a constructor call (including a C
2899 function returning a BLKmode struct) to initialize
2900 an argument. */
2902 {
2903 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2906 #else
2908 #endif
2910 {
2912 NULL_RTX);
2915 /* stack_arg_under_construction says whether a stack
2916 arg is being constructed at the old stack level.
2917 Pushing the stack gets a clean outgoing argument
2918 block. */
2919 old_stack_arg_under_construction
2922 /* Make a new map for the new argument list. */
2927 }
2929 BITS_PER_UNIT);
2930 }
2931 /* If argument evaluation might modify the stack pointer,
2932 copy the address of the argument list to a register. */
2935 {
2938 }
2939 }
2940 }
2941 }
2945 /* If we push args individually in reverse order, perform stack alignment
2946 before the first push (the last arg). */
2949 {
2950 /* When the stack adjustment is pending, we get better code
2951 by combining the adjustments. */
2955 {
2956 pending_stack_adjust
2957 = (combine_pending_stack_adjustment_and_call
2960 preferred_unit_stack_boundary));
2962 }
2966 }
2967 /* Now that the stack is properly aligned, pops can't safely
2968 be deferred during the evaluation of the arguments. */
2969 NO_DEFER_POP;
2973 /* Figure out the register where the value, if any, will come back. */
2977 {
2981 else
2983 }
2985 /* Precompute all register parameters. It isn't safe to compute anything
2986 once we have started filling any specific hard regs. */
2989 #ifdef REG_PARM_STACK_SPACE
2990 /* Save the fixed argument area if it's part of the caller's frame and
2991 is clobbered by argument setup for this call. */
2995 #endif
2997 /* Now store (and compute if necessary) all non-register parms.
2998 These come before register parms, since they can require block-moves,
2999 which could clobber the registers used for register parms.
3000 Parms which have partial registers are not stored here,
3001 but we do preallocate space here if they want that. */
3005 {
3010 reg_parm_stack_space)
3015 }
3017 /* If we have a parm that is passed in registers but not in memory
3018 and whose alignment does not permit a direct copy into registers,
3019 make a group of pseudos that correspond to each register that we
3020 will later fill. */
3024 /* Now store any partially-in-registers parm.
3025 This is the last place a block-move can happen. */
3029 {
3034 reg_parm_stack_space)
3039 }
3041 /* If we pushed args in forward order, perform stack alignment
3042 after pushing the last arg. */
3047 /* If register arguments require space on the stack and stack space
3048 was not preallocated, allocate stack space here for arguments
3049 passed in registers. */
3050 #ifdef OUTGOING_REG_PARM_STACK_SPACE
3054 #endif
3056 /* Pass the function the address in which to return a
3057 structure value. */
3059 {
3063 NULL_RTX)));
3067 }
3075 /* Perform postincrements before actually calling the function. */
3078 /* Save a pointer to the last insn before the call, so that we can
3079 later safely search backwards to find the CALL_INSN. */
3082 /* Set up next argument register. For sibling calls on machines
3083 with register windows this should be the incoming register. */
3084 #ifdef FUNCTION_INCOMING_ARG
3088 else
3089 #endif
3093 /* All arguments and registers used for the call must be set up by
3094 now! */
3096 /* Stack must be properly aligned now. */
3100 /* Generate the actual call instruction. */
3106 /* Verify that we've deallocated all the stack we used. */
3111 /* If call is cse'able, make appropriate pair of reg-notes around it.
3112 Test valreg so we don't crash; may safely ignore `const'
3113 if return type is void. Disable for PARALLEL return values, because
3114 we have no way to move such values into a pseudo register. */
3116 {
3117 rtx insns;
3120 {
3124 }
3125 else
3126 {
3130 /* Mark the return value as a pointer if needed. */
3135 /* Construct an "equal form" for the value which mentions all the
3136 arguments in order as well as the function name. */
3150 note);
3155 }
3156 }
3158 {
3162 /* The return value from a malloc-like function is a pointer. */
3168 /* The return value from a malloc-like function can not alias
3169 anything else. */
3174 /* Write out the sequence. */
3179 }
3181 /* For calls to `setjmp', etc., inform flow.c it should complain
3182 if nonvolatile values are live. For functions that cannot return,
3183 inform flow that control does not fall through. */
3186 {
3187 /* The barrier must be emitted
3188 immediately after the CALL_INSN. Some ports emit more
3189 than just a CALL_INSN above, so we must search for it here. */
3193 {
3195 /* There was no CALL_INSN? */
3198 }
3201 }
3206 /* If this function is returning into a memory location marked as
3207 readonly, it means it is initializing that location. But we normally
3208 treat functions as not clobbering such locations, so we need to
3209 specify that this one does. */
3214 /* If value type not void, return an rtx for the value. */
3216 /* If there are cleanups to be called, don't use a hard reg as target.
3217 We need to double check this and see if it matters anymore. */
3219 {
3224 }
3230 {
3232 {
3233 target
3236 structure_value_addr));
3238 }
3239 }
3241 {
3242 /* This is the special C++ case where we need to
3243 know what the true target was. We take care to
3244 never use this value more than once in one expression. */
3248 }
3249 /* Handle calls that return values in multiple non-contiguous locations.
3250 The Irix 6 ABI has examples of this. */
3252 {
3254 {
3255 /* This will only be assigned once, so it can be readonly. */
3262 }
3268 /* We can not support sibling calls for this case. */
3270 }
3274 {
3275 /* TARGET and VALREG cannot be equal at this point because the
3276 latter would not have REG_FUNCTION_VALUE_P true, while the
3277 former would if it were referring to the same register.
3279 If they refer to the same register, this move will be a no-op,
3280 except when function inlining is being done. */
3282 }
3284 {
3287 /* We can not support sibling calls for this case. */
3289 }
3290 else
3293 #ifdef PROMOTE_FUNCTION_RETURN
3294 /* If we promoted this return value, make the proper SUBREG. TARGET
3295 might be const0_rtx here, so be careful. */
3299 {
3304 /* If we don't promote as expected, something is wrong. */
3312 {
3319 }
3323 }
3324 #endif
3326 /* If size of args is variable or this was a constructor call for a stack
3327 argument, restore saved stack-pointer value. */
3330 {
3337 }
3339 {
3340 #ifdef REG_PARM_STACK_SPACE
3344 #endif
3346 /* If we saved any argument areas, restore them. */
3349 {
3351 rtx stack_area
3358 else
3361 BLOCK_OP_CALL_PARM);
3362 }
3366 }
3368 /* If this was alloca, record the new stack level for nonlocal gotos.
3369 Check for the handler slots since we might not have a save area
3370 for non-local gotos. */
3375 /* Free up storage we no longer need. */
3381 {
3382 /* Undo the fake expand_start_target_temps we did earlier. If
3383 there had been any cleanups created, we've already set
3384 sibcall_failure. */
3386 }
3392 {
3395 /* Restore the pending stack adjustment now that we have
3396 finished generating the sibling call sequence. */
3401 /* Prepare arg structure for next iteration. */
3403 {
3407 }
3410 }
3411 else
3414 /* If something prevents making this a sibling call,
3415 zero out the sequence. */
3418 }
3420 /* The function optimize_sibling_and_tail_recursive_calls doesn't
3421 handle CALL_PLACEHOLDERs inside other CALL_PLACEHOLDERs. This
3422 can happen if the arguments to this function call an inline
3423 function who's expansion contains another CALL_PLACEHOLDER.
3425 If there are any C_Ps in any of these sequences, replace them
3426 with their normal call. */
3443 /* If this was a potential tail recursion site, then emit a
3444 CALL_PLACEHOLDER with the normal and the tail recursion streams.
3445 One of them will be selected later. */
3447 {
3448 /* The tail recursion label must be kept around. We could expose
3449 its use in the CALL_PLACEHOLDER, but that creates unwanted edges
3450 and makes determining true tail recursion sites difficult.
3452 So we set LABEL_PRESERVE_P here, then clear it when we select
3453 one of the call sequences after rtl generation is complete. */
3457 tail_call_insns,
3458 tail_recursion_insns,
3459 tail_recursion_label));
3460 }
3461 else
3464 currently_expanding_call--;
3466 /* If this function returns with the stack pointer depressed, ensure
3467 this block saves and restores the stack pointer, show it was
3468 changed, and adjust for any outgoing arg space. */
3470 {
3475 }
3478 }
3479 \f
3480 /* Output a library call to function FUN (a SYMBOL_REF rtx).
3481 The RETVAL parameter specifies whether return value needs to be saved, other
3482 parameters are documented in the emit_library_call function below. */
3484 static rtx
3487 rtx orgfun;
3488 rtx value;
3493 {
3494 /* Total size in bytes of all the stack-parms scanned so far. */
3496 /* Size of arguments before any adjustments (such as rounding). */
3499 rtx fun;
3504 CUMULATIVE_ARGS args_so_far;
3505 struct arg
3506 {
3507 rtx value;
3509 rtx reg;
3513 rtx save_area;
3514 };
3519 rtx valreg;
3525 rtx before_call;
3528 #ifdef REG_PARM_STACK_SPACE
3529 /* Define the boundary of the register parm stack space that needs to be
3530 save, if any. */
3533 #endif
3535 /* Size of the stack reserved for parameter registers. */
3539 #ifdef REG_PARM_STACK_SPACE
3540 #ifdef MAYBE_REG_PARM_STACK_SPACE
3542 #else
3544 #endif
3545 #endif
3547 /* By default, library functions can not throw. */
3551 {
3578 }
3581 /* Ensure current function's preferred stack boundary is at least
3582 what we need. */
3586 /* If this kind of value comes back in memory,
3587 decide where in memory it should come back. */
3589 {
3592 {
3593 #ifdef PCC_STATIC_STRUCT_RETURN
3594 rtx pointer_reg
3604 else
3606 #endif
3607 /* This call returns a big structure. */
3609 }
3610 }
3611 else
3614 /* ??? Unfinished: must pass the memory address as an argument. */
3616 /* Copy all the libcall-arguments out of the varargs data
3617 and into a vector ARGVEC.
3619 Compute how to pass each argument. We only support a very small subset
3620 of the full argument passing conventions to limit complexity here since
3621 library functions shouldn't have many args. */
3626 #ifdef INIT_CUMULATIVE_LIBCALL_ARGS
3628 #else
3630 #endif
3637 /* Now we are about to start emitting insns that can be deleted
3638 if a libcall is deleted. */
3644 /* If there's a structure value address to be passed,
3645 either pass it in the special place, or pass it as an extra argument. */
3647 {
3649 nargs++;
3651 /* Make sure it is a reasonable operand for a move or push insn. */
3661 #ifdef FUNCTION_ARG_PARTIAL_NREGS
3664 #endif
3667 #ifdef STACK_PARMS_IN_REG_PARM_AREA
3669 #else
3671 #endif
3681 count++;
3682 }
3685 {
3689 /* We cannot convert the arg value to the mode the library wants here;
3690 must do it earlier where we know the signedness of the arg. */
3695 /* On some machines, there's no way to pass a float to a library fcn.
3696 Pass it as a double instead. */
3697 #ifdef LIBGCC_NEEDS_DOUBLE
3700 #endif
3702 /* There's no need to call protect_from_queue, because
3703 either emit_move_insn or emit_push_insn will do that. */
3705 /* Make sure it is a reasonable operand for a move or push insn. */
3710 #ifdef FUNCTION_ARG_PASS_BY_REFERENCE
3712 {
3713 rtx slot;
3715 #ifdef FUNCTION_ARG_CALLEE_COPIES
3718 #endif
3719 ;
3721 /* loop.c won't look at CALL_INSN_FUNCTION_USAGE of const/pure
3722 functions, so we have to pretend this isn't such a function. */
3724 {
3728 }
3731 /* If this was a CONST function, it is now PURE since
3732 it now reads memory. */
3734 {
3737 }
3742 {
3746 }
3747 else
3748 {
3751 slot
3757 }
3761 call_fusage);
3765 slot),
3766 call_fusage);
3770 }
3771 #endif
3778 #ifdef FUNCTION_ARG_PARTIAL_NREGS
3781 #else
3783 #endif
3786 #ifdef STACK_PARMS_IN_REG_PARM_AREA
3788 #else
3790 #endif
3805 }
3807 #ifdef FINAL_REG_PARM_STACK_SPACE
3810 #endif
3811 /* If this machine requires an external definition for library
3812 functions, write one out. */
3817 + stack_pointer_delta
3819 / STACK_BYTES
3824 reg_parm_stack_space);
3826 #ifndef OUTGOING_REG_PARM_STACK_SPACE
3828 #endif
3834 {
3835 /* Since the stack pointer will never be pushed, it is possible for
3836 the evaluation of a parm to clobber something we have already
3837 written to the stack. Since most function calls on RISC machines
3838 do not use the stack, this is uncommon, but must work correctly.
3840 Therefore, we save any area of the stack that was already written
3841 and that we are using. Here we set up to do this by making a new
3842 stack usage map from the old one.
3844 Another approach might be to try to reorder the argument
3845 evaluations to avoid this conflicting stack usage. */
3849 #ifndef OUTGOING_REG_PARM_STACK_SPACE
3850 /* Since we will be writing into the entire argument area, the
3851 map must be allocated for its entire size, not just the part that
3852 is the responsibility of the caller. */
3854 #endif
3856 #ifdef ARGS_GROW_DOWNWARD
3859 #else
3861 needed);
3862 #endif
3867 initial_highest_arg_in_use);
3874 /* We must be careful to use virtual regs before they're instantiated,
3875 and real regs afterwards. Loop optimization, for example, can create
3876 new libcalls after we've instantiated the virtual regs, and if we
3877 use virtuals anyway, they won't match the rtl patterns. */
3881 else
3883 }
3884 else
3885 {
3888 }
3890 /* If we push args individually in reverse order, perform stack alignment
3891 before the first push (the last arg). */
3897 {
3900 }
3901 else
3902 {
3905 }
3907 #ifdef REG_PARM_STACK_SPACE
3909 {
3910 /* The argument list is the property of the called routine and it
3911 may clobber it. If the fixed area has been used for previous
3912 parameters, we must save and restore it. */
3915 }
3916 #endif
3918 /* Push the args that need to be pushed. */
3920 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
3921 are to be pushed. */
3923 {
3931 {
3933 {
3934 /* If this is being stored into a pre-allocated, fixed-size,
3935 stack area, save any previous data at that location. */
3937 #ifdef ARGS_GROW_DOWNWARD
3938 /* stack_slot is negative, but we want to index stack_usage_map
3939 with positive values. */
3942 #else
3945 #endif
3948 /* Don't worry about things in the fixed argument area;
3949 it has already been saved. */
3953 i++;
3956 {
3957 /* We need to make a save area. See what mode we can make
3958 it. */
3959 enum machine_mode save_mode
3963 rtx stack_area
3964 = gen_rtx_MEM
3966 memory_address
3973 }
3974 }
3981 /* Now mark the segment we just used. */
3986 NO_DEFER_POP;
3987 }
3988 }
3990 /* If we pushed args in forward order, perform stack alignment
3991 after pushing the last arg. */
3998 else
4003 /* Now load any reg parms into their regs. */
4005 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
4006 are to be pushed. */
4008 {
4013 /* Handle calls that pass values in multiple non-contiguous
4014 locations. The PA64 has examples of this for library calls. */
4020 NO_DEFER_POP;
4021 }
4023 /* Any regs containing parms remain in use through the call. */
4025 {
4031 }
4033 /* Pass the function the address in which to return a structure value. */
4035 {
4039 NULL_RTX)));
4042 }
4044 /* Don't allow popping to be deferred, since then
4045 cse'ing of library calls could delete a call and leave the pop. */
4046 NO_DEFER_POP;
4050 /* Stack must be properly aligned now. */
4056 /* We pass the old value of inhibit_defer_pop + 1 to emit_call_1, which
4057 will set inhibit_defer_pop to that value. */
4058 /* The return type is needed to decide how many bytes the function pops.
4059 Signedness plays no role in that, so for simplicity, we pretend it's
4060 always signed. We also assume that the list of arguments passed has
4061 no impact, so we pretend it is unknown. */
4067 struct_value_size,
4069 valreg,
4072 /* For calls to `setjmp', etc., inform flow.c it should complain
4073 if nonvolatile values are live. For functions that cannot return,
4074 inform flow that control does not fall through. */
4077 {
4078 /* The barrier note must be emitted
4079 immediately after the CALL_INSN. Some ports emit more than
4080 just a CALL_INSN above, so we must search for it here. */
4084 {
4086 /* There was no CALL_INSN? */
4089 }
4092 }
4094 /* Now restore inhibit_defer_pop to its actual original value. */
4095 OK_DEFER_POP;
4097 /* If call is cse'able, make appropriate pair of reg-notes around it.
4098 Test valreg so we don't crash; may safely ignore `const'
4099 if return type is void. Disable for PARALLEL return values, because
4100 we have no way to move such values into a pseudo register. */
4102 {
4103 rtx insns;
4106 {
4110 }
4111 else
4112 {
4114 rtx temp;
4118 {
4122 }
4126 /* Construct an "equal form" for the value which mentions all the
4127 arguments in order as well as the function name. */
4140 note);
4145 }
4146 }
4149 /* Copy the value to the right place. */
4151 {
4153 {
4158 }
4160 {
4164 }
4167 else
4169 }
4172 {
4173 #ifdef REG_PARM_STACK_SPACE
4177 #endif
4179 /* If we saved any argument areas, restore them. */
4182 {
4184 rtx stack_area
4186 memory_address
4192 }
4196 }
4200 }
4201 \f
4202 /* Output a library call to function FUN (a SYMBOL_REF rtx)
4203 (emitting the queue unless NO_QUEUE is nonzero),
4204 for a value of mode OUTMODE,
4205 with NARGS different arguments, passed as alternating rtx values
4206 and machine_modes to convert them to.
4207 The rtx values should have been passed through protect_from_queue already.
4209 FN_TYPE should be LCT_NORMAL for `normal' calls, LCT_CONST for `const'
4210 calls, LCT_PURE for `pure' calls, LCT_CONST_MAKE_BLOCK for `const' calls
4211 which should be enclosed in REG_LIBCALL/REG_RETVAL notes,
4212 LCT_PURE_MAKE_BLOCK for `purep' calls which should be enclosed in
4213 REG_LIBCALL/REG_RETVAL notes with extra (use (memory (scratch)),
4214 or other LCT_ value for other types of library calls. */
4216 void
4219 {
4229 }
4230 \f
4231 /* Like emit_library_call except that an extra argument, VALUE,
4232 comes second and says where to store the result.
4233 (If VALUE is zero, this function chooses a convenient way
4234 to return the value.
4236 This function returns an rtx for where the value is to be found.
4237 If VALUE is nonzero, VALUE is returned. */
4239 rtx
4243 {
4244 rtx result;
4259 }
4260 \f
4261 /* Store a single argument for a function call
4262 into the register or memory area where it must be passed.
4263 *ARG describes the argument value and where to pass it.
4265 ARGBLOCK is the address of the stack-block for all the arguments,
4266 or 0 on a machine where arguments are pushed individually.
4268 MAY_BE_ALLOCA nonzero says this could be a call to `alloca'
4269 so must be careful about how the stack is used.
4271 VARIABLE_SIZE nonzero says that this was a variable-sized outgoing
4272 argument stack. This is used if ACCUMULATE_OUTGOING_ARGS to indicate
4273 that we need not worry about saving and restoring the stack.
4275 FNDECL is the declaration of the function we are calling.
4277 Return nonzero if this arg should cause sibcall failure,
4278 zero otherwise. */
4280 static int
4283 rtx argblock;
4287 {
4298 /* Push a new temporary level for any temporaries we make for
4299 this argument. */
4303 {
4304 /* If this is being stored into a pre-allocated, fixed-size, stack area,
4305 save any previous data at that location. */
4307 {
4308 #ifdef ARGS_GROW_DOWNWARD
4309 /* stack_slot is negative, but we want to index stack_usage_map
4310 with positive values. */
4313 else
4317 #else
4320 else
4324 #endif
4327 /* Don't worry about things in the fixed argument area;
4328 it has already been saved. */
4332 i++;
4335 {
4336 /* We need to make a save area. See what mode we can make it. */
4337 enum machine_mode save_mode
4339 rtx stack_area
4345 {
4354 BLOCK_OP_CALL_PARM);
4355 }
4356 else
4357 {
4360 }
4361 }
4362 }
4363 }
4365 /* If this isn't going to be placed on both the stack and in registers,
4366 set up the register and number of words. */
4368 {
4371 else
4374 }
4377 /* Being passed entirely in a register. We shouldn't be called in
4378 this case. */
4381 /* If this arg needs special alignment, don't load the registers
4382 here. */
4386 /* If this is being passed partially in a register, we can't evaluate
4387 it directly into its stack slot. Otherwise, we can. */
4389 {
4390 /* stack_arg_under_construction is nonzero if a function argument is
4391 being evaluated directly into the outgoing argument list and
4392 expand_call must take special action to preserve the argument list
4393 if it is called recursively.
4395 For scalar function arguments stack_usage_map is sufficient to
4396 determine which stack slots must be saved and restored. Scalar
4397 arguments in general have pass_on_stack == 0.
4399 If this argument is initialized by a function which takes the
4400 address of the argument (a C++ constructor or a C function
4401 returning a BLKmode structure), then stack_usage_map is
4402 insufficient and expand_call must push the stack around the
4403 function call. Such arguments have pass_on_stack == 1.
4405 Note that it is always safe to set stack_arg_under_construction,
4406 but this generates suboptimal code if set when not needed. */
4409 stack_arg_under_construction++;
4412 (partial
4417 /* If we are promoting object (or for any other reason) the mode
4418 doesn't agree, convert the mode. */
4425 stack_arg_under_construction--;
4426 }
4428 /* Don't allow anything left on stack from computation
4429 of argument to alloca. */
4434 /* If the value is already in the stack slot, we are done. */
4435 ;
4437 {
4440 /* Argument is a scalar, not entirely passed in registers.
4441 (If part is passed in registers, arg->partial says how much
4442 and emit_push_insn will take care of putting it there.)
4444 Push it, and if its size is less than the
4445 amount of space allocated to it,
4446 also bump stack pointer by the additional space.
4447 Note that in C the default argument promotions
4448 will prevent such mismatches. */
4451 /* Compute how much space the push instruction will push.
4452 On many machines, pushing a byte will advance the stack
4453 pointer by a halfword. */
4454 #ifdef PUSH_ROUNDING
4456 #endif
4459 /* Compute how much space the argument should get:
4460 round up to a multiple of the alignment for arguments. */
4466 /* This isn't already where we want it on the stack, so put it there.
4467 This can either be done with push or copy insns. */
4473 /* Unless this is a partially-in-register argument, the argument is now
4474 in the stack. */
4477 }
4478 else
4479 {
4480 /* BLKmode, at least partly to be pushed. */
4484 rtx size_rtx;
4486 /* Pushing a nonscalar.
4487 If part is passed in registers, PARTIAL says how much
4488 and emit_push_insn will take care of putting it there. */
4490 /* Round its size up to a multiple
4491 of the allocation unit for arguments. */
4494 {
4497 }
4498 else
4499 {
4500 /* PUSH_ROUNDING has no effect on us, because
4501 emit_push_insn for BLKmode is careful to avoid it. */
4506 }
4508 /* Some types will require stricter alignment, which will be
4509 provided for elsewhere in argument layout. */
4512 /* When an argument is padded down, the block is aligned to
4513 PARM_BOUNDARY, but the actual argument isn't. */
4515 {
4519 {
4522 }
4523 }
4526 {
4527 /* emit_push_insn might not work properly if arg->value and
4528 argblock + arg->offset areas overlap. */
4535 current_function_internal_arg_pointer
4537 {
4541 /* expand_call should ensure this */
4546 {
4549 }
4551 {
4554 }
4555 }
4556 }
4563 /* Unless this is a partially-in-register argument, the argument is now
4564 in the stack.
4566 ??? Unlike the case above, in which we want the actual
4567 address of the data, so that we can load it directly into a
4568 register, here we want the address of the stack slot, so that
4569 it's properly aligned for word-by-word copying or something
4570 like that. It's not clear that this is always correct. */
4573 }
4575 /* Mark all slots this store used. */
4581 /* Once we have pushed something, pops can't safely
4582 be deferred during the rest of the arguments. */
4583 NO_DEFER_POP;
4585 /* ANSI doesn't require a sequence point here,
4586 but PCC has one, so this will avoid some problems. */
4589 /* Free any temporary slots made in processing this argument. Show
4590 that we might have taken the address of something and pushed that
4591 as an operand. */
4597 }
4599 /* Nonzero if we do not know how to pass TYPE solely in registers.
4600 We cannot do so in the following cases:
4602 - if the type has variable size
4603 - if the type is marked as addressable (it is required to be constructed
4604 into the stack)
4605 - if the padding and mode of the type is such that a copy into a register
4606 would put it into the wrong part of the register.
4608 Which padding can't be supported depends on the byte endianness.
4610 A value in a register is implicitly padded at the most significant end.
4611 On a big-endian machine, that is the lower end in memory.
4612 So a value padded in memory at the upper end can't go in a register.
4613 For a little-endian machine, the reverse is true. */
4615 bool
4618 tree type;
4619 {
4623 /* If the type has variable size... */
4627 /* If the type is marked as addressable (it is required
4628 to be constructed into the stack)... */
4632 /* If the padding and mode of the type is such that a copy into
4633 a register would put it into the wrong part of the register. */
4641 }