| blob | 6bec3df19a0863095ff7bc8b467550302da1e171 |
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. */
41 /* Decide whether a function's arguments should be processed
42 from first to last or from last to first.
44 They should if the stack and args grow in opposite directions, but
45 only if we have push insns. */
47 #ifdef PUSH_ROUNDING
49 #ifndef PUSH_ARGS_REVERSED
50 #if defined (STACK_GROWS_DOWNWARD) != defined (ARGS_GROW_DOWNWARD)
51 #define PUSH_ARGS_REVERSED PUSH_ARGS
52 #endif
53 #endif
55 #endif
57 #ifndef PUSH_ARGS_REVERSED
58 #define PUSH_ARGS_REVERSED 0
59 #endif
61 #ifndef STACK_POINTER_OFFSET
62 #define STACK_POINTER_OFFSET 0
63 #endif
65 /* Like PREFERRED_STACK_BOUNDARY but in units of bytes, not bits. */
66 #define STACK_BYTES (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT)
68 /* Data structure and subroutines used within expand_call. */
70 struct arg_data
71 {
72 /* Tree node for this argument. */
73 tree tree_value;
74 /* Mode for value; TYPE_MODE unless promoted. */
76 /* Current RTL value for argument, or 0 if it isn't precomputed. */
77 rtx value;
78 /* Initially-compute RTL value for argument; only for const functions. */
79 rtx initial_value;
80 /* Register to pass this argument in, 0 if passed on stack, or an
81 PARALLEL if the arg is to be copied into multiple non-contiguous
82 registers. */
83 rtx reg;
84 /* Register to pass this argument in when generating tail call sequence.
85 This is not the same register as for normal calls on machines with
86 register windows. */
87 rtx tail_call_reg;
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 registers to use. 0 means put the whole arg in registers.
92 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 /* Offset of this argument from beginning of stack-args. */
101 /* Similar, but offset to the start of the stack slot. Different from
102 OFFSET if this arg pads downward. */
104 /* Size of this argument on the stack, rounded up for any padding it gets,
105 parts of the argument passed in registers do not count.
106 If REG_PARM_STACK_SPACE is defined, then register parms
107 are counted here as well. */
109 /* Location on the stack at which parameter should be stored. The store
110 has already been done if STACK == VALUE. */
111 rtx stack;
112 /* Location on the stack of the start of this argument slot. This can
113 differ from STACK if this arg pads downward. This location is known
114 to be aligned to FUNCTION_ARG_BOUNDARY. */
115 rtx stack_slot;
116 /* Place that this stack area has been saved, if needed. */
117 rtx save_area;
118 /* If an argument's alignment does not permit direct copying into registers,
119 copy in smaller-sized pieces into pseudos. These are stored in a
120 block pointed to by this field. The next field says how many
121 word-sized pseudos we made. */
124 /* The amount that the stack pointer needs to be adjusted to
125 force alignment for the next argument. */
127 };
129 /* A vector of one char per byte of stack space. A byte if nonzero if
130 the corresponding stack location has been used.
131 This vector is used to prevent a function call within an argument from
132 clobbering any stack already set up. */
135 /* Size of STACK_USAGE_MAP. */
138 /* A bitmap of virtual-incoming stack space. Bit is set if the corresponding
139 stack location's tail call argument has been already stored into the stack.
140 This bitmap is used to prevent sibling call optimization if function tries
141 to use parent's incoming argument slots when they have been already
142 overwritten with tail call arguments. */
145 /* stack_arg_under_construction is nonzero when an argument may be
146 initialized with a constructor call (including a C function that
147 returns a BLKmode struct) and expand_call must take special action
148 to make sure the object being constructed does not overlap the
149 argument list for the constructor call. */
158 CUMULATIVE_ARGS *));
178 CUMULATIVE_ARGS *,
198 static int combine_pending_stack_adjustment_and_call
202 #ifdef REG_PARM_STACK_SPACE
205 #endif
206 \f
207 /* If WHICH is 1, return 1 if EXP contains a call to the built-in function
208 `alloca'.
210 If WHICH is 0, return 1 if EXP contains a call to any function.
211 Actually, we only need return 1 if evaluating EXP would require pushing
212 arguments on the stack, but that is too difficult to compute, so we just
213 assume any function call might require the stack. */
217 static int
219 tree exp;
221 {
228 }
230 /* Recursive function to do the work of above function. */
232 static int
234 tree exp;
236 {
242 /* If this code is language-specific, we don't know what it will do. */
247 {
253 && (TYPE_RETURNS_STACK_DEPRESSED
267 {
268 tree tem;
273 }
283 calls_function_save_exprs);
288 {
289 tree local;
290 tree subblock;
298 subblock;
302 }
313 }
315 /* Only expressions, references, and blocks can contain calls. */
325 }
326 \f
327 /* Force FUNEXP into a form suitable for the address of a CALL,
328 and return that as an rtx. Also load the static chain register
329 if FNDECL is a nested function.
331 CALL_FUSAGE points to a variable holding the prospective
332 CALL_INSN_FUNCTION_USAGE information. */
334 rtx
336 rtx funexp;
337 tree fndecl;
341 {
347 /* Get possible static chain value for nested function in C. */
350 /* Make a valid memory address and copy constants thru pseudo-regs,
351 but not for a constant address if -fno-function-cse. */
353 /* If we are using registers for parameters, force the
354 function address into a register now. */
359 {
360 #ifndef NO_FUNCTION_CSE
362 #ifdef NO_RECURSIVE_FUNCTION_CSE
364 #endif
366 #endif
367 }
370 {
375 }
378 }
380 /* Generate instructions to call function FUNEXP,
381 and optionally pop the results.
382 The CALL_INSN is the first insn generated.
384 FNDECL is the declaration node of the function. This is given to the
385 macro RETURN_POPS_ARGS to determine whether this function pops its own args.
387 FUNTYPE is the data type of the function. This is given to the macro
388 RETURN_POPS_ARGS to determine whether this function pops its own args.
389 We used to allow an identifier for library functions, but that doesn't
390 work when the return type is an aggregate type and the calling convention
391 says that the pointer to this aggregate is to be popped by the callee.
393 STACK_SIZE is the number of bytes of arguments on the stack,
394 ROUNDED_STACK_SIZE is that number rounded up to
395 PREFERRED_STACK_BOUNDARY; zero if the size is variable. This is
396 both to put into the call insn and to generate explicit popping
397 code if necessary.
399 STRUCT_VALUE_SIZE is the number of bytes wanted in a structure value.
400 It is zero if this call doesn't want a structure value.
402 NEXT_ARG_REG is the rtx that results from executing
403 FUNCTION_ARG (args_so_far, VOIDmode, void_type_node, 1)
404 just after all the args have had their registers assigned.
405 This could be whatever you like, but normally it is the first
406 arg-register beyond those used for args in this call,
407 or 0 if all the arg-registers are used in this call.
408 It is passed on to `gen_call' so you can put this info in the call insn.
410 VALREG is a hard register in which a value is returned,
411 or 0 if the call does not return a value.
413 OLD_INHIBIT_DEFER_POP is the value that `inhibit_defer_pop' had before
414 the args to this call were processed.
415 We restore `inhibit_defer_pop' to that value.
417 CALL_FUSAGE is either empty or an EXPR_LIST of USE expressions that
418 denote registers used by the called function. */
420 static void
424 rtx funexp;
425 tree fndecl ATTRIBUTE_UNUSED;
426 tree funtype ATTRIBUTE_UNUSED;
427 HOST_WIDE_INT stack_size ATTRIBUTE_UNUSED;
428 HOST_WIDE_INT rounded_stack_size;
429 HOST_WIDE_INT struct_value_size ATTRIBUTE_UNUSED;
430 rtx next_arg_reg ATTRIBUTE_UNUSED;
431 rtx valreg;
433 rtx call_fusage;
436 {
438 rtx call_insn;
441 #if defined (HAVE_call) && defined (HAVE_call_value)
442 rtx struct_value_size_rtx;
444 #endif
446 #ifdef CALL_POPS_ARGS
448 #endif
450 /* Ensure address is valid. SYMBOL_REF is already valid, so no need,
451 and we don't want to load it into a register as an optimization,
452 because prepare_call_address already did it if it should be done. */
456 #if defined (HAVE_sibcall_pop) && defined (HAVE_sibcall_value_pop)
460 {
462 rtx pat;
464 /* If this subroutine pops its own args, record that in the call insn
465 if possible, for the sake of frame pointer elimination. */
471 n_pop);
472 else
478 }
479 else
480 #endif
482 #if defined (HAVE_call_pop) && defined (HAVE_call_value_pop)
483 /* If the target has "call" or "call_value" insns, then prefer them
484 if no arguments are actually popped. If the target does not have
485 "call" or "call_value" insns, then we must use the popping versions
486 even if the call has no arguments to pop. */
487 #if defined (HAVE_call) && defined (HAVE_call_value)
490 #else
492 #endif
493 {
495 rtx pat;
497 /* If this subroutine pops its own args, record that in the call insn
498 if possible, for the sake of frame pointer elimination. */
504 else
510 }
511 else
512 #endif
514 #if defined (HAVE_sibcall) && defined (HAVE_sibcall_value)
517 {
521 rounded_stack_size_rtx,
523 else
526 struct_value_size_rtx));
527 }
528 else
529 #endif
531 #if defined (HAVE_call) && defined (HAVE_call_value)
533 {
538 NULL_RTX));
539 else
542 struct_value_size_rtx));
543 }
544 else
545 #endif
548 /* Find the CALL insn we just emitted. */
552 ;
557 /* Mark memory as used for "pure" function call. */
559 call_fusage
560 = gen_rtx_EXPR_LIST
564 call_fusage);
566 /* Put the register usage information on the CALL. If there is already
567 some usage information, put ours at the end. */
569 {
570 rtx link;
574 ;
577 }
578 else
581 /* If this is a const call, then set the insn's unchanging bit. */
585 /* If this call can't throw, attach a REG_EH_REGION reg note to that
586 effect. */
599 {
603 }
607 /* Restore this now, so that we do defer pops for this call's args
608 if the context of the call as a whole permits. */
612 {
621 }
624 {
625 /* If returning from the subroutine does not automatically pop the args,
626 we need an instruction to pop them sooner or later.
627 Perhaps do it now; perhaps just record how much space to pop later.
629 If returning from the subroutine does pop the args, indicate that the
630 stack pointer will be changed. */
633 {
635 /* Just pretend we did the pop. */
640 else
642 }
643 }
644 /* When we accumulate outgoing args, we must avoid any stack manipulations.
645 Restore the stack pointer to its original value now. Usually
646 ACCUMULATE_OUTGOING_ARGS targets don't get here, but there are exceptions.
647 On i386 ACCUMULATE_OUTGOING_ARGS can be enabled on demand, and
648 popping variants of functions exist as well.
650 ??? We may optimize similar to defer_pop above, but it is
651 probably not worthwhile.
653 ??? It will be worthwhile to enable combine_stack_adjustments even for
654 such machines. */
657 }
659 /* Determine if the function identified by NAME and FNDECL is one with
660 special properties we wish to know about.
662 For example, if the function might return more than one time (setjmp), then
663 set RETURNS_TWICE to a nonzero value.
665 Similarly set LONGJMP for if the function is in the longjmp family.
667 Set MALLOC for any of the standard memory allocation functions which
668 allocate from the heap.
670 Set MAY_BE_ALLOCA for any memory allocation function that might allocate
671 space from the stack such as alloca. */
673 static int
675 tree fndecl;
677 {
681 /* Exclude functions not at the file scope, or not `extern',
682 since they are not the magic functions we would otherwise
683 think they are. */
685 {
689 /* We assume that alloca will always be called by name. It
690 makes no sense to pass it as a pointer-to-function to
691 anything that does not understand its behavior. */
700 /* Disregard prefix _, __ or __x. */
702 {
707 else
709 }
712 {
725 }
738 /* Linux specific: __clone. check NAME to insist on the
739 leading underscores, to avoid polluting the ISO / POSIX
740 namespace. */
750 /* Do not add any more malloc-like functions to this list,
751 instead mark them as malloc functions using the malloc attribute.
752 Note, realloc is not suitable for attribute malloc since
753 it may return the same address across multiple calls.
754 C++ operator new is not suitable because it is not required
755 to return a unique pointer; indeed, the standard placement new
756 just returns its argument. */
762 }
764 }
766 /* Return nonzero when tree represent call to longjmp. */
768 int
770 tree fndecl;
771 {
773 }
775 /* Return true when exp contains alloca call. */
776 bool
778 tree exp;
779 {
788 }
790 /* Detect flags (function attributes) from the function decl or type node. */
792 int
794 tree exp;
795 {
798 /* ??? We can't set IS_MALLOC for function types? */
800 {
803 /* The function exp may have the `malloc' attribute. */
807 /* The function exp may have the `pure' attribute. */
813 }
821 /* Mark if the function returns with the stack pointer depressed. We
822 cannot consider it pure or constant in that case. */
824 {
827 }
830 }
832 /* Precompute all register parameters as described by ARGS, storing values
833 into fields within the ARGS array.
835 NUM_ACTUALS indicates the total number elements in the ARGS array.
837 Set REG_PARM_SEEN if we encounter a register parameter. */
839 static void
844 {
851 {
855 {
862 /* ANSI doesn't require a sequence point here,
863 but PCC has one, so this will avoid some problems. */
865 }
867 /* If the value is a non-legitimate constant, force it into a
868 pseudo now. TLS symbols sometimes need a call to resolve. */
873 /* If we are to promote the function arg to a wider mode,
874 do it now. */
882 /* If the value is expensive, and we are inside an appropriately
883 short loop, put the value into a pseudo and then put the pseudo
884 into the hard reg.
886 For small register classes, also do this if this call uses
887 register parameters. This is to avoid reload conflicts while
888 loading the parameters registers. */
898 }
899 }
901 #ifdef REG_PARM_STACK_SPACE
903 /* The argument list is the property of the called routine and it
904 may clobber it. If the fixed area has been used for previous
905 parameters, we must save and restore it. */
907 static rtx
911 rtx argblock;
914 {
918 /* Compute the boundary of the area that needs to be saved, if any. */
920 #ifdef ARGS_GROW_DOWNWARD
922 #endif
928 {
932 rtx stack_area;
933 rtx save_area;
936 ;
944 /* If we don't have the required alignment, must do this
945 in BLKmode. */
950 #ifdef ARGS_GROW_DOWNWARD
952 #else
954 #endif
958 delta)));
962 {
966 }
967 else
968 {
971 }
974 }
977 }
979 static void
981 rtx save_area;
982 rtx argblock;
985 {
988 rtx stack_area;
990 #ifdef ARGS_GROW_DOWNWARD
992 #else
994 #endif
1002 else
1005 BLOCK_OP_CALL_PARM);
1006 }
1009 /* If any elements in ARGS refer to parameters that are to be passed in
1010 registers, but not in memory, and whose alignment does not permit a
1011 direct copy into registers. Copy the values into a group of pseudos
1012 which we will later copy into the appropriate hard registers.
1014 Pseudos for each unaligned argument will be stored into the array
1015 args[argnum].aligned_regs. The caller is responsible for deallocating
1016 the aligned_regs array if it is nonzero. */
1018 static void
1022 {
1030 {
1041 /* Structures smaller than a word are aligned to the least
1042 significant byte (to the right). On a BYTES_BIG_ENDIAN machine,
1043 this means we must skip the empty high order bytes when
1044 calculating the bit offset. */
1050 {
1057 /* There is no need to restrict this code to loading items
1058 in TYPE_ALIGN sized hunks. The bitfield instructions can
1059 load up entire word sized registers efficiently.
1061 ??? This may not be needed anymore.
1062 We use to emit a clobber here but that doesn't let later
1063 passes optimize the instructions we emit. By storing 0 into
1064 the register later passes know the first AND to zero out the
1065 bitfield being set in the register is unnecessary. The store
1066 of 0 will be deleted as will at least the first AND. */
1074 BITS_PER_WORD),
1075 BITS_PER_WORD);
1076 }
1077 }
1078 }
1080 /* Fill in ARGS_SIZE and ARGS array based on the parameters found in
1081 ACTPARMS.
1083 NUM_ACTUALS is the total number of parameters.
1085 N_NAMED_ARGS is the total number of named arguments.
1087 FNDECL is the tree code for the target of this call (if known)
1089 ARGS_SO_FAR holds state needed by the target to know where to place
1090 the next argument.
1092 REG_PARM_STACK_SPACE is the number of bytes of stack space reserved
1093 for arguments which are passed in registers.
1095 OLD_STACK_LEVEL is a pointer to an rtx which olds the old stack level
1096 and may be modified by this routine.
1098 OLD_PENDING_ADJ, MUST_PREALLOCATE and FLAGS are pointers to integer
1099 flags which may may be modified by this routine. */
1101 static void
1106 ecf_flags)
1111 tree actparms;
1112 tree fndecl;
1119 {
1120 /* 1 if scanning parms front to back, -1 if scanning back to front. */
1123 /* Count arg position in order args appear. */
1128 tree p;
1133 /* In this loop, we consider args in the order they are written.
1134 We fill up ARGS from the front or from the back if necessary
1135 so that in any case the first arg to be pushed ends up at the front. */
1138 {
1140 /* In this case, must reverse order of args
1141 so that we compute and push the last arg first. */
1142 }
1143 else
1144 {
1146 }
1148 /* I counts args in order (to be) pushed; ARGPOS counts in order written. */
1150 {
1157 /* Replace erroneous argument with constant zero. */
1161 /* If TYPE is a transparent union, pass things the way we would
1162 pass the first field of the union. We have already verified that
1163 the modes are the same. */
1167 /* Decide where to pass this arg.
1169 args[i].reg is nonzero if all or part is passed in registers.
1171 args[i].partial is nonzero if part but not all is passed in registers,
1172 and the exact value says how many words are passed in registers.
1174 args[i].pass_on_stack is nonzero if the argument must at least be
1175 computed on the stack. It may then be loaded back into registers
1176 if args[i].reg is nonzero.
1178 These decisions are driven by the FUNCTION_... macros and must agree
1179 with those made by function.c. */
1181 /* See if this argument should be passed by invisible reference. */
1185 #ifdef FUNCTION_ARG_PASS_BY_REFERENCE
1188 #endif
1189 )
1190 {
1191 /* If we're compiling a thunk, pass through invisible
1192 references instead of making a copy. */
1194 #ifdef FUNCTION_ARG_CALLEE_COPIES
1197 /* If it's in a register, we must make a copy of it too. */
1198 /* ??? Is this a sufficient test? Is there a better one? */
1202 #endif
1203 )
1204 {
1205 /* C++ uses a TARGET_EXPR to indicate that we want to make a
1206 new object from the argument. If we are passing by
1207 invisible reference, the callee will do that for us, so we
1208 can strip off the TARGET_EXPR. This is not always safe,
1209 but it is safe in the only case where this is a useful
1210 optimization; namely, when the argument is a plain object.
1211 In that case, the frontend is just asking the backend to
1212 make a bitwise copy of the argument. */
1223 }
1225 {
1226 /* In the V3 C++ ABI, parameters are destroyed in the caller.
1227 We implement this by passing the address of the temporary
1228 rather than expanding it into another allocated slot. */
1233 }
1234 else
1235 {
1236 /* We make a copy of the object and pass the address to the
1237 function being called. */
1238 rtx copy;
1244 STACK_CHECK_MAX_VAR_SIZE))))
1245 {
1246 /* This is a variable-sized object. Make space on the stack
1247 for it. */
1251 {
1255 }
1258 allocate_dynamic_stack_space
1261 }
1262 else
1272 }
1273 }
1278 #ifdef PROMOTE_FUNCTION_ARGS
1280 #endif
1287 #ifdef FUNCTION_INCOMING_ARG
1288 /* If this is a sibling call and the machine has register windows, the
1289 register window has to be unwinded before calling the routine, so
1290 arguments have to go into the incoming registers. */
1293 #else
1295 #endif
1297 #ifdef FUNCTION_ARG_PARTIAL_NREGS
1302 #endif
1306 /* If FUNCTION_ARG returned a (parallel [(expr_list (nil) ...) ...]),
1307 it means that we are to pass this arg in the register(s) designated
1308 by the PARALLEL, but also to pass it in the stack. */
1313 /* If this is an addressable type, we must preallocate the stack
1314 since we must evaluate the object into its final location.
1316 If this is to be passed in both registers and the stack, it is simpler
1317 to preallocate. */
1322 /* If this is an addressable type, we cannot pre-evaluate it. Thus,
1323 we cannot consider this function call constant. */
1327 /* Compute the stack-size of this argument. */
1332 #ifdef STACK_PARMS_IN_REG_PARM_AREA
1334 #else
1336 #endif
1340 #ifndef ARGS_GROW_DOWNWARD
1342 #endif
1346 /* If a part of the arg was put into registers,
1347 don't include that part in the amount pushed. */
1353 /* Update ARGS_SIZE, the total stack space for args so far. */
1357 {
1359 }
1361 /* Since the slot offset points to the bottom of the slot,
1362 we must record it after incrementing if the args grow down. */
1363 #ifdef ARGS_GROW_DOWNWARD
1369 #endif
1371 /* Increment ARGS_SO_FAR, which has info about which arg-registers
1372 have been used, etc. */
1376 }
1377 }
1379 /* Update ARGS_SIZE to contain the total size for the argument block.
1380 Return the original constant component of the argument block's size.
1382 REG_PARM_STACK_SPACE holds the number of bytes of stack space reserved
1383 for arguments passed in registers. */
1385 static int
1387 preferred_stack_boundary)
1391 {
1394 /* For accumulate outgoing args mode we don't need to align, since the frame
1395 will be already aligned. Align to STACK_BOUNDARY in order to prevent
1396 backends from generating misaligned frame sizes. */
1400 /* Compute the actual size of the argument block required. The variable
1401 and constant sizes must be combined, the size may have to be rounded,
1402 and there may be a minimum required size. */
1405 {
1411 {
1412 /* We don't handle this case yet. To handle it correctly we have
1413 to add the delta, round and subtract the delta.
1414 Currently no machine description requires this support. */
1418 }
1421 {
1422 args_size->var
1426 #ifndef OUTGOING_REG_PARM_STACK_SPACE
1427 /* The area corresponding to register parameters is not to count in
1428 the size of the block we need. So make the adjustment. */
1429 args_size->var
1432 #endif
1433 }
1434 }
1435 else
1436 {
1441 + stack_pointer_delta
1443 / preferred_stack_boundary
1448 reg_parm_stack_space);
1450 #ifdef MAYBE_REG_PARM_STACK_SPACE
1453 #endif
1455 #ifndef OUTGOING_REG_PARM_STACK_SPACE
1457 #endif
1458 }
1460 }
1462 /* Precompute parameters as needed for a function call.
1464 FLAGS is mask of ECF_* constants.
1466 NUM_ACTUALS is the number of arguments.
1468 ARGS is an array containing information for each argument; this
1469 routine fills in the INITIAL_VALUE and VALUE fields for each
1470 precomputed argument. */
1472 static void
1477 {
1480 /* If this function call is cse'able, precompute all the parameters.
1481 Note that if the parameter is constructed into a temporary, this will
1482 cause an additional copy because the parameter will be constructed
1483 into a temporary location and then copied into the outgoing arguments.
1484 If a parameter contains a call to alloca and this function uses the
1485 stack, precompute the parameter. */
1487 /* If we preallocated the stack space, and some arguments must be passed
1488 on the stack, then we must precompute any parameter which contains a
1489 function call which will store arguments on the stack.
1490 Otherwise, evaluating the parameter may clobber previous parameters
1491 which have already been stored into the stack. (we have code to avoid
1492 such case by saving the outgoing stack arguments, but it results in
1493 worse code) */
1498 {
1501 /* If this is an addressable type, we cannot pre-evaluate it. */
1508 /* ANSI doesn't require a sequence point here,
1509 but PCC has one, so this will avoid some problems. */
1517 {
1521 #ifdef PROMOTE_FOR_CALL_ONLY
1522 /* CSE will replace this only if it contains args[i].value
1523 pseudo, so convert it down to the declared mode using
1524 a SUBREG. */
1527 {
1533 }
1534 #endif
1535 }
1536 }
1537 }
1539 /* Given the current state of MUST_PREALLOCATE and information about
1540 arguments to a function call in NUM_ACTUALS, ARGS and ARGS_SIZE,
1541 compute and return the final value for MUST_PREALLOCATE. */
1543 static int
1549 {
1550 /* See if we have or want to preallocate stack space.
1552 If we would have to push a partially-in-regs parm
1553 before other stack parms, preallocate stack space instead.
1555 If the size of some parm is not a multiple of the required stack
1556 alignment, we must preallocate.
1558 If the total size of arguments that would otherwise create a copy in
1559 a temporary (such as a CALL) is more than half the total argument list
1560 size, preallocation is faster.
1562 Another reason to preallocate is if we have a machine (like the m88k)
1563 where stack alignment is required to be maintained between every
1564 pair of insns, not just when the call is made. However, we assume here
1565 that such machines either do not have push insns (and hence preallocation
1566 would occur anyway) or the problem is taken care of with
1567 PUSH_ROUNDING. */
1570 {
1576 {
1587 copy_to_evaluate_size
1589 }
1594 }
1596 }
1598 /* If we preallocated stack space, compute the address of each argument
1599 and store it into the ARGS array.
1601 We need not ensure it is a valid memory address here; it will be
1602 validized when it is used.
1604 ARGBLOCK is an rtx for the address of the outgoing arguments. */
1606 static void
1609 rtx argblock;
1611 {
1613 {
1621 {
1624 rtx addr;
1626 /* Skip this parm if it will not be passed on the stack. */
1632 else
1642 else
1650 /* Function incoming arguments may overlap with sibling call
1651 outgoing arguments and we cannot allow reordering of reads
1652 from function arguments with stores to outgoing arguments
1653 of sibling calls. */
1656 }
1657 }
1658 }
1660 /* Given a FNDECL and EXP, return an rtx suitable for use as a target address
1661 in a call instruction.
1663 FNDECL is the tree node for the target function. For an indirect call
1664 FNDECL will be NULL_TREE.
1666 EXP is the CALL_EXPR for this call. */
1668 static rtx
1670 tree fndecl;
1671 tree exp;
1672 {
1673 rtx funexp;
1675 /* Get the function to call, in the form of RTL. */
1677 {
1678 /* If this is the first use of the function, see if we need to
1679 make an external definition for it. */
1681 {
1684 }
1686 /* Get a SYMBOL_REF rtx for the function address. */
1688 }
1689 else
1690 /* Generate an rtx (probably a pseudo-register) for the address. */
1691 {
1696 }
1698 }
1700 /* Do the register loads required for any wholly-register parms or any
1701 parms which are passed both on the stack and in a register. Their
1702 expressions were already evaluated.
1704 Mark all register-parms as living through the call, putting these USE
1705 insns in the CALL_INSN_FUNCTION_USAGE field.
1707 When IS_SIBCALL, perform the check_sibcall_overlap_argument_overlap
1708 checking, setting *SIBCALL_FAILURE if appropriate. */
1710 static void
1719 {
1722 #ifdef LOAD_ARGS_REVERSED
1724 #else
1726 #endif
1727 {
1734 {
1736 /* Set to non-negative if must move a word at a time, even if just
1737 one word (e.g, partial == 1 && mode == DFmode). Set to -1 if
1738 we just use a normal move insn. This value can be zero if the
1739 argument is a zero size structure with no fields. */
1746 /* Handle calls that pass values in multiple non-contiguous
1747 locations. The Irix 6 ABI has examples of this. */
1753 /* If simple case, just do move. If normal partial, store_one_arg
1754 has already loaded the register for us. In all other cases,
1755 load the register(s) from memory. */
1760 /* If we have pre-computed the values to put in the registers in
1761 the case of non-aligned structures, copy them in now. */
1773 /* When a parameter is a block, and perhaps in other cases, it is
1774 possible that it did a load from an argument slot that was
1775 already clobbered. */
1780 /* Handle calls that pass values in multiple non-contiguous
1781 locations. The Irix 6 ABI has examples of this. */
1786 else
1788 }
1789 }
1790 }
1792 /* Try to integrate function. See expand_inline_function for documentation
1793 about the parameters. */
1795 static rtx
1797 tree fndecl;
1798 tree actparms;
1799 rtx target;
1801 tree type;
1802 rtx structure_value_addr;
1803 {
1804 rtx temp;
1805 rtx before_call;
1810 #ifdef REG_PARM_STACK_SPACE
1811 #ifdef MAYBE_REG_PARM_STACK_SPACE
1813 #else
1815 #endif
1816 #endif
1824 structure_value_addr);
1828 /* If inlining succeeded, return. */
1830 {
1832 {
1833 /* If the outgoing argument list must be preserved, push
1834 the stack before executing the inlined function if it
1835 makes any calls. */
1841 ;
1844 {
1845 rtx first_insn
1849 /* Look for a call in the inline function code.
1850 If DECL_SAVED_INSNS (fndecl)->outgoing_args_size is
1851 nonzero then there is a call and it is not necessary
1852 to scan the insns. */
1860 {
1861 /* Reserve enough stack space so that the largest
1862 argument list of any function call in the inline
1863 function does not overlap the argument list being
1864 evaluated. This is usually an overestimate because
1865 allocate_dynamic_stack_space reserves space for an
1866 outgoing argument list in addition to the requested
1867 space, but there is no way to ask for stack space such
1868 that an argument list of a certain length can be
1869 safely constructed.
1871 Add the stack space reserved for register arguments, if
1872 any, in the inline function. What is really needed is the
1873 largest value of reg_parm_stack_space in the inline
1874 function, but that is not available. Using the current
1875 value of reg_parm_stack_space is wrong, but gives
1876 correct results on all supported machines. */
1889 }
1890 }
1891 }
1893 /* If the result is equivalent to TARGET, return TARGET to simplify
1894 checks in store_expr. They can be equivalent but not equal in the
1895 case of a function that returns BLKmode. */
1899 }
1901 /* If inlining failed, mark FNDECL as needing to be compiled
1902 separately after all. If function was declared inline,
1903 give a warning. */
1906 {
1909 }
1912 }
1914 /* We need to pop PENDING_STACK_ADJUST bytes. But, if the arguments
1915 wouldn't fill up an even multiple of PREFERRED_UNIT_STACK_BOUNDARY
1916 bytes, then we would need to push some additional bytes to pad the
1917 arguments. So, we compute an adjust to the stack pointer for an
1918 amount that will leave the stack under-aligned by UNADJUSTED_ARGS_SIZE
1919 bytes. Then, when the arguments are pushed the stack will be perfectly
1920 aligned. ARGS_SIZE->CONSTANT is set to the number of bytes that should
1921 be popped after the call. Returns the adjustment. */
1923 static int
1925 args_size,
1926 preferred_unit_stack_boundary)
1930 {
1931 /* The number of bytes to pop so that the stack will be
1932 under-aligned by UNADJUSTED_ARGS_SIZE bytes. */
1933 HOST_WIDE_INT adjustment;
1934 /* The alignment of the stack after the arguments are pushed, if we
1935 just pushed the arguments without adjust the stack here. */
1936 HOST_WIDE_INT unadjusted_alignment;
1938 unadjusted_alignment
1942 /* We want to get rid of as many of the PENDING_STACK_ADJUST bytes
1943 as possible -- leaving just enough left to cancel out the
1944 UNADJUSTED_ALIGNMENT. In other words, we want to ensure that the
1945 PENDING_STACK_ADJUST is non-negative, and congruent to
1946 -UNADJUSTED_ALIGNMENT modulo the PREFERRED_UNIT_STACK_BOUNDARY. */
1948 /* Begin by trying to pop all the bytes. */
1949 unadjusted_alignment
1950 = (unadjusted_alignment
1953 /* Push enough additional bytes that the stack will be aligned
1954 after the arguments are pushed. */
1956 {
1959 else
1961 }
1963 /* Now, sets ARGS_SIZE->CONSTANT so that we pop the right number of
1964 bytes after the call. The right number is the entire
1965 PENDING_STACK_ADJUST less our ADJUSTMENT plus the amount required
1966 by the arguments in the first place. */
1967 args_size->constant
1971 }
1973 /* Scan X expression if it does not dereference any argument slots
1974 we already clobbered by tail call arguments (as noted in stored_args_map
1975 bitmap).
1976 Return nonzero if X expression dereferences such argument slots,
1977 zero otherwise. */
1979 static int
1981 rtx x;
1982 {
1983 RTX_CODE code;
1994 {
1999 current_function_internal_arg_pointer
2002 else
2005 #ifdef ARGS_GROW_DOWNWARD
2007 #endif
2015 }
2017 /* Scan all subexpressions. */
2020 {
2022 {
2025 }
2027 {
2031 }
2032 }
2034 }
2036 /* Scan sequence after INSN if it does not dereference any argument slots
2037 we already clobbered by tail call arguments (as noted in stored_args_map
2038 bitmap). If MARK_STORED_ARGS_MAP, add stack slots for ARG to
2039 stored_args_map bitmap afterwards (when ARG is a register MARK_STORED_ARGS_MAP
2040 should be 0). Return nonzero if sequence after INSN dereferences such argument
2041 slots, zero otherwise. */
2043 static int
2045 rtx insn;
2048 {
2053 else
2062 {
2063 #ifdef ARGS_GROW_DOWNWARD
2065 #else
2067 #endif
2071 }
2073 }
2075 static tree
2077 tree t;
2078 {
2080 {
2089 {
2095 }
2100 }
2102 }
2104 /* Generate all the code for a function call
2105 and return an rtx for its value.
2106 Store the value in TARGET (specified as an rtx) if convenient.
2107 If the value is stored in TARGET then TARGET is returned.
2108 If IGNORE is nonzero, then we ignore the value of the function call. */
2110 rtx
2112 tree exp;
2113 rtx target;
2115 {
2116 /* Nonzero if we are currently expanding a call. */
2119 /* List of actual parameters. */
2121 /* RTX for the function to be called. */
2122 rtx funexp;
2123 /* Sequence of insns to perform a tail recursive "call". */
2125 /* Sequence of insns to perform a normal "call". */
2127 /* Sequence of insns to perform a tail recursive "call". */
2129 /* Data type of the function. */
2130 tree funtype;
2131 /* Declaration of the function being called,
2132 or 0 if the function is computed (not known by name). */
2134 rtx insn;
2139 /* Register in which non-BLKmode value will be returned,
2140 or 0 if no value or if value is BLKmode. */
2141 rtx valreg;
2142 /* Address where we should return a BLKmode value;
2143 0 if value not BLKmode. */
2145 /* Nonzero if that address is being passed by treating it as
2146 an extra, implicit first parameter. Otherwise,
2147 it is passed by being copied directly into struct_value_rtx. */
2149 /* Size of aggregate value wanted, or zero if none wanted
2150 or if we are using the non-reentrant PCC calling convention
2151 or expecting the value in registers. */
2153 /* Nonzero if called function returns an aggregate in memory PCC style,
2154 by returning the address of where to find it. */
2157 /* Number of actual parameters in this call, including struct value addr. */
2159 /* Number of named args. Args after this are anonymous ones
2160 and they must all go on the stack. */
2163 /* Vector of information about each argument.
2164 Arguments are numbered in the order they will be pushed,
2165 not the order they are written. */
2168 /* Total size in bytes of all the stack-parms scanned so far. */
2171 /* Size of arguments before any adjustments (such as rounding). */
2173 /* Data on reg parms scanned so far. */
2174 CUMULATIVE_ARGS args_so_far;
2175 /* Nonzero if a reg parm has been scanned. */
2177 /* Nonzero if this is an indirect function call. */
2179 /* Nonzero if we must avoid push-insns in the args for this call.
2180 If stack space is allocated for register parameters, but not by the
2181 caller, then it is preallocated in the fixed part of the stack frame.
2182 So the entire argument block must then be preallocated (i.e., we
2183 ignore PUSH_ROUNDING in that case). */
2187 /* Size of the stack reserved for parameter registers. */
2190 /* Address of space preallocated for stack parms
2191 (on machines that lack push insns), or 0 if space not preallocated. */
2194 /* Mask of ECF_ flags. */
2196 /* Nonzero if this is a call to an inline function. */
2198 #ifdef REG_PARM_STACK_SPACE
2199 /* Define the boundary of the register parm stack space that needs to be
2200 saved, if any. */
2203 #endif
2213 rtx call_fusage;
2216 /* The alignment of the stack, in bits. */
2217 HOST_WIDE_INT preferred_stack_boundary;
2218 /* The alignment of the stack, in bytes. */
2219 HOST_WIDE_INT preferred_unit_stack_boundary;
2221 /* See if this is "nothrow" function call. */
2225 /* See if we can find a DECL-node for the actual function.
2226 As a result, decide whether this is a call to an integrable function. */
2230 {
2238 {
2239 /* In case this function later becomes inlinable,
2240 record that there was already a non-inline call to it.
2242 Use abstraction instead of setting TREE_ADDRESSABLE
2243 directly. */
2246 {
2249 }
2251 }
2254 }
2256 /* If we don't have specific function to call, see if we have a
2257 attributes set in the type. */
2258 else
2261 #ifdef REG_PARM_STACK_SPACE
2262 #ifdef MAYBE_REG_PARM_STACK_SPACE
2264 #else
2266 #endif
2267 #endif
2269 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2272 #endif
2274 /* Warn if this value is an aggregate type,
2275 regardless of which calling convention we are using for it. */
2279 /* Set up a place to return a structure. */
2281 /* Cater to broken compilers. */
2283 {
2284 /* This call returns a big structure. */
2287 #ifdef PCC_STATIC_STRUCT_RETURN
2288 {
2290 /* Easier than making that case work right. */
2292 {
2293 /* In case this is a static function, note that it has been
2294 used. */
2298 }
2299 }
2301 {
2305 {
2306 /* The structure value address arg is already in actparms.
2307 Pull it out. It might be nice to just leave it there, but
2308 we need to set structure_value_addr. */
2313 }
2316 else
2317 {
2318 /* For variable-sized objects, we must be called with a target
2319 specified. If we were to allocate space on the stack here,
2320 we would have no way of knowing when to free it. */
2326 }
2327 }
2329 }
2331 /* If called function is inline, try to integrate it. */
2334 {
2337 structure_value_addr);
2340 }
2342 /* Figure out the amount to which the stack should be aligned. */
2345 /* Operand 0 is a pointer-to-function; get the type of the function. */
2351 /* See if this is a call to a function that can return more than once
2352 or a call to longjmp or malloc. */
2358 /* If struct_value_rtx is 0, it means pass the address
2359 as if it were an extra parameter. */
2361 {
2362 /* If structure_value_addr is a REG other than
2363 virtual_outgoing_args_rtx, we can use always use it. If it
2364 is not a REG, we must always copy it into a register.
2365 If it is virtual_outgoing_args_rtx, we must copy it to another
2366 register in some cases. */
2368 || (ACCUMULATE_OUTGOING_ARGS
2369 && stack_arg_under_construction
2374 actparms
2377 temp),
2378 actparms);
2380 }
2382 /* Count the arguments and set NUM_ACTUALS. */
2384 num_actuals++;
2386 /* Compute number of named args.
2387 Normally, don't include the last named arg if anonymous args follow.
2388 We do include the last named arg if STRICT_ARGUMENT_NAMING is nonzero.
2389 (If no anonymous args follow, the result of list_length is actually
2390 one too large. This is harmless.)
2392 If PRETEND_OUTGOING_VARARGS_NAMED is set and STRICT_ARGUMENT_NAMING is
2393 zero, this machine will be able to place unnamed args that were
2394 passed in registers into the stack. So treat all args as named.
2395 This allows the insns emitting for a specific argument list to be
2396 independent of the function declaration.
2398 If PRETEND_OUTGOING_VARARGS_NAMED is not set, we do not have any
2399 reliable way to pass unnamed args in registers, so we must force
2400 them into memory. */
2405 n_named_args
2407 /* Don't include the last named arg. */
2409 /* Count the struct value address, if it is passed as a parm. */
2411 else
2412 /* If we know nothing, treat all args as named. */
2415 /* Start updating where the next arg would go.
2417 On some machines (such as the PA) indirect calls have a different
2418 calling convention than normal calls. The last argument in
2419 INIT_CUMULATIVE_ARGS tells the backend if this is an indirect call
2420 or not. */
2423 /* Make a vector to hold all the information about each arg. */
2427 /* Build up entries in the ARGS array, compute the size of the
2428 arguments into ARGS_SIZE, etc. */
2436 {
2437 /* If this function requires a variable-sized argument list, don't
2438 try to make a cse'able block for this call. We may be able to
2439 do this eventually, but it is too complicated to keep track of
2440 what insns go in the cse'able block and which don't. */
2444 }
2446 /* Now make final decision about preallocating stack space. */
2451 /* If the structure value address will reference the stack pointer, we
2452 must stabilize it. We don't need to do this if we know that we are
2453 not going to adjust the stack pointer in processing this call. */
2458 structure_value_addr))
2463 /* Tail calls can make things harder to debug, and we're traditionally
2464 pushed these optimizations into -O2. Don't try if we're already
2465 expanding a call, as that means we're an argument. Don't try if
2466 there's cleanups, as we know there's code to follow the call.
2468 If rtx_equal_function_value_matters is false, that means we've
2469 finished with regular parsing. Which means that some of the
2470 machinery we use to generate tail-calls is no longer in place.
2471 This is most often true of sjlj-exceptions, which we couldn't
2472 tail-call to anyway. */
2475 || !flag_optimize_sibling_calls
2476 || !rtx_equal_function_value_matters
2481 /* Tail recursion fails, when we are not dealing with recursive calls. */
2487 /* Rest of purposes for tail call optimizations to fail. */
2489 #ifdef HAVE_sibcall_epilogue
2490 !HAVE_sibcall_epilogue
2491 #else
2492 1
2493 #endif
2494 || !try_tail_call
2495 /* Doing sibling call optimization needs some work, since
2496 structure_value_addr can be allocated on the stack.
2497 It does not seem worth the effort since few optimizable
2498 sibling calls will return a structure. */
2500 /* Check whether the target is able to optimize the call
2501 into a sibcall. */
2503 /* Functions that do not return exactly once may not be sibcall
2504 optimized. */
2507 /* If this function requires more stack slots than the current
2508 function, we cannot change it into a sibling call. */
2510 /* If the callee pops its own arguments, then it must pop exactly
2511 the same number of arguments as the current function. */
2515 current_function_args_size))
2519 {
2522 /* Ok, we're going to give the tail call the old college try.
2523 This means we're going to evaluate the function arguments
2524 up to three times. There are two degrees of badness we can
2525 encounter, those that can be unsaved and those that can't.
2526 (See unsafe_for_reeval commentary for details.)
2528 Generate a new argument list. Pass safe arguments through
2529 unchanged. For the easy badness wrap them in UNSAVE_EXPRs.
2530 For hard badness, evaluate them now and put their resulting
2531 rtx in a temporary VAR_DECL.
2533 initialize_argument_information has ordered the array for the
2534 order to be pushed, and we must remember this when reconstructing
2535 the original argument order. */
2538 {
2542 }
2543 else
2544 {
2548 }
2551 {
2553 /* We need to build actparms for optimize_tail_recursion. We can
2554 safely trash away TREE_PURPOSE, since it is unused by this
2555 function. */
2558 }
2559 /* Do the same for the function address if it is an expression. */
2562 /* Expanding one of those dangerous arguments could have added
2563 cleanups, but otherwise give it a whirl. */
2566 }
2568 /* Generate a tail recursion sequence when calling ourselves. */
2571 {
2572 /* We want to emit any pending stack adjustments before the tail
2573 recursion "call". That way we know any adjustment after the tail
2574 recursion call can be ignored if we indeed use the tail recursion
2575 call expansion. */
2579 /* Emit any queued insns now; otherwise they would end up in
2580 only one of the alternates. */
2583 /* Use a new sequence to hold any RTL we generate. We do not even
2584 know if we will use this RTL yet. The final decision can not be
2585 made until after RTL generation for the entire function is
2586 complete. */
2588 /* If expanding any of the arguments creates cleanups, we can't
2589 do a tailcall. So, we'll need to pop the pending cleanups
2590 list. If, however, all goes well, and there are no cleanups
2591 then the call to expand_start_target_temps will have no
2592 effect. */
2595 {
2598 else
2600 }
2604 /* Restore the original pending stack adjustment for the sibling and
2605 normal call cases below. */
2608 }
2611 {
2612 /* A fork duplicates the profile information, and an exec discards
2613 it. We can't rely on fork/exec to be paired. So write out the
2614 profile information we have gathered so far, and clear it. */
2615 /* ??? When Linux's __clone is called with CLONE_VM set, profiling
2616 is subject to race conditions, just as with multithreaded
2617 programs. */
2620 LCT_ALWAYS_RETURN,
2622 }
2624 /* Ensure current function's preferred stack boundary is at least
2625 what we need. We don't have to increase alignment for recursive
2626 functions. */
2633 function_call_count++;
2635 /* We want to make two insn chains; one for a sibling call, the other
2636 for a normal call. We will select one of the two chains after
2637 initial RTL generation is complete. */
2639 {
2641 /* We want to emit any pending stack adjustments before the tail
2642 recursion "call". That way we know any adjustment after the tail
2643 recursion call can be ignored if we indeed use the tail recursion
2644 call expansion. */
2647 rtx insns;
2651 {
2652 /* Emit any queued insns now; otherwise they would end up in
2653 only one of the alternates. */
2656 /* State variables we need to save and restore between
2657 iterations. */
2660 }
2663 else
2666 /* Other state variables that we must reinitialize each time
2667 through the loop (that are not initialized by the loop itself). */
2671 /* Start a new sequence for the normal call case.
2673 From this point on, if the sibling call fails, we want to set
2674 sibcall_failure instead of continuing the loop. */
2678 {
2679 /* We know at this point that there are not currently any
2680 pending cleanups. If, however, in the process of evaluating
2681 the arguments we were to create some, we'll need to be
2682 able to get rid of them. */
2684 }
2686 /* Don't let pending stack adjusts add up to too much.
2687 Also, do all pending adjustments now if there is any chance
2688 this might be a call to alloca or if we are expanding a sibling
2689 call sequence or if we are calling a function that is to return
2690 with stack pointer depressed. */
2697 /* When calling a const function, we must pop the stack args right away,
2698 so that the pop is deleted or moved with the call. */
2700 NO_DEFER_POP;
2702 #ifdef FINAL_REG_PARM_STACK_SPACE
2705 #endif
2706 /* Precompute any arguments as needed. */
2710 /* Now we are about to start emitting insns that can be deleted
2711 if a libcall is deleted. */
2716 /* Compute the actual size of the argument block required. The variable
2717 and constant sizes must be combined, the size may have to be rounded,
2718 and there may be a minimum required size. When generating a sibcall
2719 pattern, do not round up, since we'll be re-using whatever space our
2720 caller provided. */
2721 unadjusted_args_size
2729 /* The argument block when performing a sibling call is the
2730 incoming argument block. */
2732 {
2734 argblock
2735 #ifdef STACK_GROWS_DOWNWARD
2737 #else
2739 #endif
2742 }
2744 /* If we have no actual push instructions, or shouldn't use them,
2745 make space for all args right now. */
2747 {
2749 {
2753 /* stack_arg_under_construction says whether a stack arg is
2754 being constructed at the old stack level. Pushing the stack
2755 gets a clean outgoing argument block. */
2758 }
2760 }
2761 else
2762 {
2763 /* Note that we must go through the motions of allocating an argument
2764 block even if the size is zero because we may be storing args
2765 in the area reserved for register arguments, which may be part of
2766 the stack frame. */
2770 /* Store the maximum argument space used. It will be pushed by
2771 the prologue (if ACCUMULATE_OUTGOING_ARGS, or stack overflow
2772 checking). */
2778 {
2780 {
2781 /* Since the stack pointer will never be pushed, it is
2782 possible for the evaluation of a parm to clobber
2783 something we have already written to the stack.
2784 Since most function calls on RISC machines do not use
2785 the stack, this is uncommon, but must work correctly.
2787 Therefore, we save any area of the stack that was already
2788 written and that we are using. Here we set up to do this
2789 by making a new stack usage map from the old one. The
2790 actual save will be done by store_one_arg.
2792 Another approach might be to try to reorder the argument
2793 evaluations to avoid this conflicting stack usage. */
2795 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2796 /* Since we will be writing into the entire argument area,
2797 the map must be allocated for its entire size, not just
2798 the part that is the responsibility of the caller. */
2800 #endif
2802 #ifdef ARGS_GROW_DOWNWARD
2805 #else
2807 needed);
2808 #endif
2809 stack_usage_map
2814 initial_highest_arg_in_use);
2818 (highest_outgoing_arg_in_use
2822 /* The address of the outgoing argument list must not be
2823 copied to a register here, because argblock would be left
2824 pointing to the wrong place after the call to
2825 allocate_dynamic_stack_space below. */
2828 }
2829 else
2830 {
2832 {
2833 /* Try to reuse some or all of the pending_stack_adjust
2834 to get this space. */
2835 needed
2836 = (combine_pending_stack_adjustment_and_call
2839 preferred_unit_stack_boundary));
2841 /* combine_pending_stack_adjustment_and_call computes
2842 an adjustment before the arguments are allocated.
2843 Account for them and see whether or not the stack
2844 needs to go up or down. */
2848 {
2849 /* We're releasing stack space. */
2850 /* ??? We can avoid any adjustment at all if we're
2851 already aligned. FIXME. */
2855 }
2856 else
2857 /* We need to allocate space. We'll do that in
2858 push_block below. */
2860 }
2862 /* Special case this because overhead of `push_block' in
2863 this case is non-trivial. */
2866 else
2869 /* We only really need to call `copy_to_reg' in the case
2870 where push insns are going to be used to pass ARGBLOCK
2871 to a function call in ARGS. In that case, the stack
2872 pointer changes value from the allocation point to the
2873 call point, and hence the value of
2874 VIRTUAL_OUTGOING_ARGS_RTX changes as well. But might
2875 as well always do it. */
2878 /* The save/restore code in store_one_arg handles all
2879 cases except one: a constructor call (including a C
2880 function returning a BLKmode struct) to initialize
2881 an argument. */
2883 {
2884 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2887 #else
2889 #endif
2891 {
2893 NULL_RTX);
2896 /* stack_arg_under_construction says whether a stack
2897 arg is being constructed at the old stack level.
2898 Pushing the stack gets a clean outgoing argument
2899 block. */
2900 old_stack_arg_under_construction
2903 /* Make a new map for the new argument list. */
2908 }
2910 BITS_PER_UNIT);
2911 }
2912 /* If argument evaluation might modify the stack pointer,
2913 copy the address of the argument list to a register. */
2916 {
2919 }
2920 }
2921 }
2922 }
2926 /* If we push args individually in reverse order, perform stack alignment
2927 before the first push (the last arg). */
2930 {
2931 /* When the stack adjustment is pending, we get better code
2932 by combining the adjustments. */
2936 {
2937 pending_stack_adjust
2938 = (combine_pending_stack_adjustment_and_call
2941 preferred_unit_stack_boundary));
2943 }
2947 }
2948 /* Now that the stack is properly aligned, pops can't safely
2949 be deferred during the evaluation of the arguments. */
2950 NO_DEFER_POP;
2954 /* Figure out the register where the value, if any, will come back. */
2958 {
2962 else
2964 }
2966 /* Precompute all register parameters. It isn't safe to compute anything
2967 once we have started filling any specific hard regs. */
2970 #ifdef REG_PARM_STACK_SPACE
2971 /* Save the fixed argument area if it's part of the caller's frame and
2972 is clobbered by argument setup for this call. */
2976 #endif
2978 /* Now store (and compute if necessary) all non-register parms.
2979 These come before register parms, since they can require block-moves,
2980 which could clobber the registers used for register parms.
2981 Parms which have partial registers are not stored here,
2982 but we do preallocate space here if they want that. */
2986 {
2991 reg_parm_stack_space)
2996 }
2998 /* If we have a parm that is passed in registers but not in memory
2999 and whose alignment does not permit a direct copy into registers,
3000 make a group of pseudos that correspond to each register that we
3001 will later fill. */
3005 /* Now store any partially-in-registers parm.
3006 This is the last place a block-move can happen. */
3010 {
3015 reg_parm_stack_space)
3020 }
3022 /* If we pushed args in forward order, perform stack alignment
3023 after pushing the last arg. */
3028 /* If register arguments require space on the stack and stack space
3029 was not preallocated, allocate stack space here for arguments
3030 passed in registers. */
3031 #ifdef OUTGOING_REG_PARM_STACK_SPACE
3035 #endif
3037 /* Pass the function the address in which to return a
3038 structure value. */
3040 {
3044 NULL_RTX)));
3048 }
3056 /* Perform postincrements before actually calling the function. */
3059 /* Save a pointer to the last insn before the call, so that we can
3060 later safely search backwards to find the CALL_INSN. */
3063 /* Set up next argument register. For sibling calls on machines
3064 with register windows this should be the incoming register. */
3065 #ifdef FUNCTION_INCOMING_ARG
3069 else
3070 #endif
3074 /* All arguments and registers used for the call must be set up by
3075 now! */
3077 /* Stack must be properly aligned now. */
3081 /* Generate the actual call instruction. */
3087 /* Verify that we've deallocated all the stack we used. */
3092 /* If call is cse'able, make appropriate pair of reg-notes around it.
3093 Test valreg so we don't crash; may safely ignore `const'
3094 if return type is void. Disable for PARALLEL return values, because
3095 we have no way to move such values into a pseudo register. */
3097 {
3098 rtx insns;
3101 {
3105 }
3106 else
3107 {
3111 /* Mark the return value as a pointer if needed. */
3116 /* Construct an "equal form" for the value which mentions all the
3117 arguments in order as well as the function name. */
3131 note);
3136 }
3137 }
3139 {
3143 /* The return value from a malloc-like function is a pointer. */
3149 /* The return value from a malloc-like function can not alias
3150 anything else. */
3155 /* Write out the sequence. */
3160 }
3162 /* For calls to `setjmp', etc., inform flow.c it should complain
3163 if nonvolatile values are live. For functions that cannot return,
3164 inform flow that control does not fall through. */
3167 {
3168 /* The barrier must be emitted
3169 immediately after the CALL_INSN. Some ports emit more
3170 than just a CALL_INSN above, so we must search for it here. */
3174 {
3176 /* There was no CALL_INSN? */
3179 }
3182 }
3187 /* If this function is returning into a memory location marked as
3188 readonly, it means it is initializing that location. But we normally
3189 treat functions as not clobbering such locations, so we need to
3190 specify that this one does. */
3195 /* If value type not void, return an rtx for the value. */
3197 /* If there are cleanups to be called, don't use a hard reg as target.
3198 We need to double check this and see if it matters anymore. */
3200 {
3205 }
3211 {
3213 {
3214 target
3217 structure_value_addr));
3219 }
3220 }
3222 {
3223 /* This is the special C++ case where we need to
3224 know what the true target was. We take care to
3225 never use this value more than once in one expression. */
3229 }
3230 /* Handle calls that return values in multiple non-contiguous locations.
3231 The Irix 6 ABI has examples of this. */
3233 {
3235 {
3236 /* This will only be assigned once, so it can be readonly. */
3243 }
3249 /* We can not support sibling calls for this case. */
3251 }
3255 {
3256 /* TARGET and VALREG cannot be equal at this point because the
3257 latter would not have REG_FUNCTION_VALUE_P true, while the
3258 former would if it were referring to the same register.
3260 If they refer to the same register, this move will be a no-op,
3261 except when function inlining is being done. */
3263 }
3265 {
3268 /* We can not support sibling calls for this case. */
3270 }
3271 else
3274 #ifdef PROMOTE_FUNCTION_RETURN
3275 /* If we promoted this return value, make the proper SUBREG. TARGET
3276 might be const0_rtx here, so be careful. */
3280 {
3285 /* If we don't promote as expected, something is wrong. */
3293 {
3300 }
3304 }
3305 #endif
3307 /* If size of args is variable or this was a constructor call for a stack
3308 argument, restore saved stack-pointer value. */
3311 {
3318 }
3320 {
3321 #ifdef REG_PARM_STACK_SPACE
3325 #endif
3327 /* If we saved any argument areas, restore them. */
3330 {
3332 rtx stack_area
3339 else
3342 BLOCK_OP_CALL_PARM);
3343 }
3347 }
3349 /* If this was alloca, record the new stack level for nonlocal gotos.
3350 Check for the handler slots since we might not have a save area
3351 for non-local gotos. */
3356 /* Free up storage we no longer need. */
3362 {
3363 /* Undo the fake expand_start_target_temps we did earlier. If
3364 there had been any cleanups created, we've already set
3365 sibcall_failure. */
3367 }
3373 {
3376 /* Restore the pending stack adjustment now that we have
3377 finished generating the sibling call sequence. */
3382 /* Prepare arg structure for next iteration. */
3384 {
3388 }
3391 }
3392 else
3395 /* If something prevents making this a sibling call,
3396 zero out the sequence. */
3399 }
3401 /* The function optimize_sibling_and_tail_recursive_calls doesn't
3402 handle CALL_PLACEHOLDERs inside other CALL_PLACEHOLDERs. This
3403 can happen if the arguments to this function call an inline
3404 function who's expansion contains another CALL_PLACEHOLDER.
3406 If there are any C_Ps in any of these sequences, replace them
3407 with their normal call. */
3424 /* If this was a potential tail recursion site, then emit a
3425 CALL_PLACEHOLDER with the normal and the tail recursion streams.
3426 One of them will be selected later. */
3428 {
3429 /* The tail recursion label must be kept around. We could expose
3430 its use in the CALL_PLACEHOLDER, but that creates unwanted edges
3431 and makes determining true tail recursion sites difficult.
3433 So we set LABEL_PRESERVE_P here, then clear it when we select
3434 one of the call sequences after rtl generation is complete. */
3438 tail_call_insns,
3439 tail_recursion_insns,
3440 tail_recursion_label));
3441 }
3442 else
3445 currently_expanding_call--;
3447 /* If this function returns with the stack pointer depressed, ensure
3448 this block saves and restores the stack pointer, show it was
3449 changed, and adjust for any outgoing arg space. */
3451 {
3456 }
3459 }
3460 \f
3461 /* Output a library call to function FUN (a SYMBOL_REF rtx).
3462 The RETVAL parameter specifies whether return value needs to be saved, other
3463 parameters are documented in the emit_library_call function below. */
3465 static rtx
3468 rtx orgfun;
3469 rtx value;
3474 {
3475 /* Total size in bytes of all the stack-parms scanned so far. */
3477 /* Size of arguments before any adjustments (such as rounding). */
3480 rtx fun;
3485 CUMULATIVE_ARGS args_so_far;
3486 struct arg
3487 {
3488 rtx value;
3490 rtx reg;
3494 rtx save_area;
3495 };
3500 rtx valreg;
3506 rtx before_call;
3509 #ifdef REG_PARM_STACK_SPACE
3510 /* Define the boundary of the register parm stack space that needs to be
3511 save, if any. */
3514 #endif
3516 /* Size of the stack reserved for parameter registers. */
3520 #ifdef REG_PARM_STACK_SPACE
3521 #ifdef MAYBE_REG_PARM_STACK_SPACE
3523 #else
3525 #endif
3526 #endif
3528 /* By default, library functions can not throw. */
3532 {
3559 }
3562 /* Ensure current function's preferred stack boundary is at least
3563 what we need. */
3567 /* If this kind of value comes back in memory,
3568 decide where in memory it should come back. */
3570 {
3573 {
3574 #ifdef PCC_STATIC_STRUCT_RETURN
3575 rtx pointer_reg
3585 else
3587 #endif
3588 /* This call returns a big structure. */
3590 }
3591 }
3592 else
3595 /* ??? Unfinished: must pass the memory address as an argument. */
3597 /* Copy all the libcall-arguments out of the varargs data
3598 and into a vector ARGVEC.
3600 Compute how to pass each argument. We only support a very small subset
3601 of the full argument passing conventions to limit complexity here since
3602 library functions shouldn't have many args. */
3607 #ifdef INIT_CUMULATIVE_LIBCALL_ARGS
3609 #else
3611 #endif
3618 /* Now we are about to start emitting insns that can be deleted
3619 if a libcall is deleted. */
3625 /* If there's a structure value address to be passed,
3626 either pass it in the special place, or pass it as an extra argument. */
3628 {
3630 nargs++;
3632 /* Make sure it is a reasonable operand for a move or push insn. */
3642 #ifdef FUNCTION_ARG_PARTIAL_NREGS
3645 #endif
3648 #ifdef STACK_PARMS_IN_REG_PARM_AREA
3650 #else
3652 #endif
3662 count++;
3663 }
3666 {
3670 /* We cannot convert the arg value to the mode the library wants here;
3671 must do it earlier where we know the signedness of the arg. */
3676 /* On some machines, there's no way to pass a float to a library fcn.
3677 Pass it as a double instead. */
3678 #ifdef LIBGCC_NEEDS_DOUBLE
3681 #endif
3683 /* There's no need to call protect_from_queue, because
3684 either emit_move_insn or emit_push_insn will do that. */
3686 /* Make sure it is a reasonable operand for a move or push insn. */
3691 #ifdef FUNCTION_ARG_PASS_BY_REFERENCE
3693 {
3694 rtx slot;
3696 #ifdef FUNCTION_ARG_CALLEE_COPIES
3699 #endif
3700 ;
3702 /* loop.c won't look at CALL_INSN_FUNCTION_USAGE of const/pure
3703 functions, so we have to pretend this isn't such a function. */
3705 {
3709 }
3712 /* If this was a CONST function, it is now PURE since
3713 it now reads memory. */
3715 {
3718 }
3723 {
3727 }
3728 else
3729 {
3732 slot
3738 }
3742 call_fusage);
3746 slot),
3747 call_fusage);
3751 }
3752 #endif
3759 #ifdef FUNCTION_ARG_PARTIAL_NREGS
3762 #else
3764 #endif
3767 #ifdef STACK_PARMS_IN_REG_PARM_AREA
3769 #else
3771 #endif
3786 }
3788 #ifdef FINAL_REG_PARM_STACK_SPACE
3791 #endif
3792 /* If this machine requires an external definition for library
3793 functions, write one out. */
3798 + stack_pointer_delta
3800 / STACK_BYTES
3805 reg_parm_stack_space);
3807 #ifndef OUTGOING_REG_PARM_STACK_SPACE
3809 #endif
3815 {
3816 /* Since the stack pointer will never be pushed, it is possible for
3817 the evaluation of a parm to clobber something we have already
3818 written to the stack. Since most function calls on RISC machines
3819 do not use the stack, this is uncommon, but must work correctly.
3821 Therefore, we save any area of the stack that was already written
3822 and that we are using. Here we set up to do this by making a new
3823 stack usage map from the old one.
3825 Another approach might be to try to reorder the argument
3826 evaluations to avoid this conflicting stack usage. */
3830 #ifndef OUTGOING_REG_PARM_STACK_SPACE
3831 /* Since we will be writing into the entire argument area, the
3832 map must be allocated for its entire size, not just the part that
3833 is the responsibility of the caller. */
3835 #endif
3837 #ifdef ARGS_GROW_DOWNWARD
3840 #else
3842 needed);
3843 #endif
3848 initial_highest_arg_in_use);
3855 /* We must be careful to use virtual regs before they're instantiated,
3856 and real regs afterwards. Loop optimization, for example, can create
3857 new libcalls after we've instantiated the virtual regs, and if we
3858 use virtuals anyway, they won't match the rtl patterns. */
3862 else
3864 }
3865 else
3866 {
3869 }
3871 /* If we push args individually in reverse order, perform stack alignment
3872 before the first push (the last arg). */
3878 {
3881 }
3882 else
3883 {
3886 }
3888 #ifdef REG_PARM_STACK_SPACE
3890 {
3891 /* The argument list is the property of the called routine and it
3892 may clobber it. If the fixed area has been used for previous
3893 parameters, we must save and restore it. */
3896 }
3897 #endif
3899 /* Push the args that need to be pushed. */
3901 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
3902 are to be pushed. */
3904 {
3912 {
3914 {
3915 /* If this is being stored into a pre-allocated, fixed-size,
3916 stack area, save any previous data at that location. */
3918 #ifdef ARGS_GROW_DOWNWARD
3919 /* stack_slot is negative, but we want to index stack_usage_map
3920 with positive values. */
3923 #else
3926 #endif
3929 /* Don't worry about things in the fixed argument area;
3930 it has already been saved. */
3934 i++;
3937 {
3938 /* We need to make a save area. See what mode we can make
3939 it. */
3940 enum machine_mode save_mode
3944 rtx stack_area
3945 = gen_rtx_MEM
3947 memory_address
3954 }
3955 }
3962 /* Now mark the segment we just used. */
3967 NO_DEFER_POP;
3968 }
3969 }
3971 /* If we pushed args in forward order, perform stack alignment
3972 after pushing the last arg. */
3979 else
3984 /* Now load any reg parms into their regs. */
3986 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
3987 are to be pushed. */
3989 {
3994 /* Handle calls that pass values in multiple non-contiguous
3995 locations. The PA64 has examples of this for library calls. */
4001 NO_DEFER_POP;
4002 }
4004 /* Any regs containing parms remain in use through the call. */
4006 {
4012 }
4014 /* Pass the function the address in which to return a structure value. */
4016 {
4020 NULL_RTX)));
4023 }
4025 /* Don't allow popping to be deferred, since then
4026 cse'ing of library calls could delete a call and leave the pop. */
4027 NO_DEFER_POP;
4031 /* Stack must be properly aligned now. */
4037 /* We pass the old value of inhibit_defer_pop + 1 to emit_call_1, which
4038 will set inhibit_defer_pop to that value. */
4039 /* The return type is needed to decide how many bytes the function pops.
4040 Signedness plays no role in that, so for simplicity, we pretend it's
4041 always signed. We also assume that the list of arguments passed has
4042 no impact, so we pretend it is unknown. */
4048 struct_value_size,
4050 valreg,
4053 /* For calls to `setjmp', etc., inform flow.c it should complain
4054 if nonvolatile values are live. For functions that cannot return,
4055 inform flow that control does not fall through. */
4058 {
4059 /* The barrier note must be emitted
4060 immediately after the CALL_INSN. Some ports emit more than
4061 just a CALL_INSN above, so we must search for it here. */
4065 {
4067 /* There was no CALL_INSN? */
4070 }
4073 }
4075 /* Now restore inhibit_defer_pop to its actual original value. */
4076 OK_DEFER_POP;
4078 /* If call is cse'able, make appropriate pair of reg-notes around it.
4079 Test valreg so we don't crash; may safely ignore `const'
4080 if return type is void. Disable for PARALLEL return values, because
4081 we have no way to move such values into a pseudo register. */
4083 {
4084 rtx insns;
4087 {
4091 }
4092 else
4093 {
4095 rtx temp;
4099 {
4103 }
4107 /* Construct an "equal form" for the value which mentions all the
4108 arguments in order as well as the function name. */
4121 note);
4126 }
4127 }
4130 /* Copy the value to the right place. */
4132 {
4134 {
4139 }
4141 {
4145 }
4148 else
4150 }
4153 {
4154 #ifdef REG_PARM_STACK_SPACE
4158 #endif
4160 /* If we saved any argument areas, restore them. */
4163 {
4165 rtx stack_area
4167 memory_address
4173 }
4177 }
4181 }
4182 \f
4183 /* Output a library call to function FUN (a SYMBOL_REF rtx)
4184 (emitting the queue unless NO_QUEUE is nonzero),
4185 for a value of mode OUTMODE,
4186 with NARGS different arguments, passed as alternating rtx values
4187 and machine_modes to convert them to.
4188 The rtx values should have been passed through protect_from_queue already.
4190 FN_TYPE should be LCT_NORMAL for `normal' calls, LCT_CONST for `const'
4191 calls, LCT_PURE for `pure' calls, LCT_CONST_MAKE_BLOCK for `const' calls
4192 which should be enclosed in REG_LIBCALL/REG_RETVAL notes,
4193 LCT_PURE_MAKE_BLOCK for `purep' calls which should be enclosed in
4194 REG_LIBCALL/REG_RETVAL notes with extra (use (memory (scratch)),
4195 or other LCT_ value for other types of library calls. */
4197 void
4200 {
4210 }
4211 \f
4212 /* Like emit_library_call except that an extra argument, VALUE,
4213 comes second and says where to store the result.
4214 (If VALUE is zero, this function chooses a convenient way
4215 to return the value.
4217 This function returns an rtx for where the value is to be found.
4218 If VALUE is nonzero, VALUE is returned. */
4220 rtx
4224 {
4225 rtx result;
4240 }
4241 \f
4242 /* Store a single argument for a function call
4243 into the register or memory area where it must be passed.
4244 *ARG describes the argument value and where to pass it.
4246 ARGBLOCK is the address of the stack-block for all the arguments,
4247 or 0 on a machine where arguments are pushed individually.
4249 MAY_BE_ALLOCA nonzero says this could be a call to `alloca'
4250 so must be careful about how the stack is used.
4252 VARIABLE_SIZE nonzero says that this was a variable-sized outgoing
4253 argument stack. This is used if ACCUMULATE_OUTGOING_ARGS to indicate
4254 that we need not worry about saving and restoring the stack.
4256 FNDECL is the declaration of the function we are calling.
4258 Return nonzero if this arg should cause sibcall failure,
4259 zero otherwise. */
4261 static int
4264 rtx argblock;
4268 {
4279 /* Push a new temporary level for any temporaries we make for
4280 this argument. */
4284 {
4285 /* If this is being stored into a pre-allocated, fixed-size, stack area,
4286 save any previous data at that location. */
4288 {
4289 #ifdef ARGS_GROW_DOWNWARD
4290 /* stack_slot is negative, but we want to index stack_usage_map
4291 with positive values. */
4294 else
4298 #else
4301 else
4305 #endif
4308 /* Don't worry about things in the fixed argument area;
4309 it has already been saved. */
4313 i++;
4316 {
4317 /* We need to make a save area. See what mode we can make it. */
4318 enum machine_mode save_mode
4320 rtx stack_area
4326 {
4335 BLOCK_OP_CALL_PARM);
4336 }
4337 else
4338 {
4341 }
4342 }
4343 }
4344 /* Now that we have saved any slots that will be overwritten by this
4345 store, mark all slots this store will use. We must do this before
4346 we actually expand the argument since the expansion itself may
4347 trigger library calls which might need to use the same stack slot. */
4351 }
4353 /* If this isn't going to be placed on both the stack and in registers,
4354 set up the register and number of words. */
4356 {
4359 else
4362 }
4365 /* Being passed entirely in a register. We shouldn't be called in
4366 this case. */
4369 /* If this arg needs special alignment, don't load the registers
4370 here. */
4374 /* If this is being passed partially in a register, we can't evaluate
4375 it directly into its stack slot. Otherwise, we can. */
4377 {
4378 /* stack_arg_under_construction is nonzero if a function argument is
4379 being evaluated directly into the outgoing argument list and
4380 expand_call must take special action to preserve the argument list
4381 if it is called recursively.
4383 For scalar function arguments stack_usage_map is sufficient to
4384 determine which stack slots must be saved and restored. Scalar
4385 arguments in general have pass_on_stack == 0.
4387 If this argument is initialized by a function which takes the
4388 address of the argument (a C++ constructor or a C function
4389 returning a BLKmode structure), then stack_usage_map is
4390 insufficient and expand_call must push the stack around the
4391 function call. Such arguments have pass_on_stack == 1.
4393 Note that it is always safe to set stack_arg_under_construction,
4394 but this generates suboptimal code if set when not needed. */
4397 stack_arg_under_construction++;
4400 (partial
4405 /* If we are promoting object (or for any other reason) the mode
4406 doesn't agree, convert the mode. */
4413 stack_arg_under_construction--;
4414 }
4416 /* Don't allow anything left on stack from computation
4417 of argument to alloca. */
4422 /* If the value is already in the stack slot, we are done. */
4423 ;
4425 {
4428 /* Argument is a scalar, not entirely passed in registers.
4429 (If part is passed in registers, arg->partial says how much
4430 and emit_push_insn will take care of putting it there.)
4432 Push it, and if its size is less than the
4433 amount of space allocated to it,
4434 also bump stack pointer by the additional space.
4435 Note that in C the default argument promotions
4436 will prevent such mismatches. */
4439 /* Compute how much space the push instruction will push.
4440 On many machines, pushing a byte will advance the stack
4441 pointer by a halfword. */
4442 #ifdef PUSH_ROUNDING
4444 #endif
4447 /* Compute how much space the argument should get:
4448 round up to a multiple of the alignment for arguments. */
4454 /* This isn't already where we want it on the stack, so put it there.
4455 This can either be done with push or copy insns. */
4461 /* Unless this is a partially-in-register argument, the argument is now
4462 in the stack. */
4465 }
4466 else
4467 {
4468 /* BLKmode, at least partly to be pushed. */
4472 rtx size_rtx;
4474 /* Pushing a nonscalar.
4475 If part is passed in registers, PARTIAL says how much
4476 and emit_push_insn will take care of putting it there. */
4478 /* Round its size up to a multiple
4479 of the allocation unit for arguments. */
4482 {
4485 }
4486 else
4487 {
4488 /* PUSH_ROUNDING has no effect on us, because
4489 emit_push_insn for BLKmode is careful to avoid it. */
4494 }
4496 /* Some types will require stricter alignment, which will be
4497 provided for elsewhere in argument layout. */
4500 /* When an argument is padded down, the block is aligned to
4501 PARM_BOUNDARY, but the actual argument isn't. */
4503 {
4507 {
4510 }
4511 }
4514 {
4515 /* emit_push_insn might not work properly if arg->value and
4516 argblock + arg->offset areas overlap. */
4523 current_function_internal_arg_pointer
4525 {
4529 /* expand_call should ensure this */
4534 {
4537 }
4539 {
4542 }
4543 }
4544 }
4546 /* Special handling is required if part of the parameter lies in the
4547 register parameter area. The argument may be copied into the stack
4548 slot using memcpy(), but the original contents of the register
4549 parameter area will be restored after the memcpy() call.
4551 To ensure that the part that lies in the register parameter area
4552 is copied correctly, we emit a separate push for that part. This
4553 push should be small enough to avoid a call to memcpy(). */
4554 #ifndef STACK_PARMS_IN_REG_PARM_AREA
4556 #else
4558 #endif
4559 {
4567 {
4573 }
4574 }
4582 /* Unless this is a partially-in-register argument, the argument is now
4583 in the stack.
4585 ??? Unlike the case above, in which we want the actual
4586 address of the data, so that we can load it directly into a
4587 register, here we want the address of the stack slot, so that
4588 it's properly aligned for word-by-word copying or something
4589 like that. It's not clear that this is always correct. */
4592 }
4594 /* Once we have pushed something, pops can't safely
4595 be deferred during the rest of the arguments. */
4596 NO_DEFER_POP;
4598 /* ANSI doesn't require a sequence point here,
4599 but PCC has one, so this will avoid some problems. */
4602 /* Free any temporary slots made in processing this argument. Show
4603 that we might have taken the address of something and pushed that
4604 as an operand. */
4610 }
4613 /* Nonzero if we do not know how to pass TYPE solely in registers.
4614 We cannot do so in the following cases:
4616 - if the type has variable size
4617 - if the type is marked as addressable (it is required to be constructed
4618 into the stack)
4619 - if the padding and mode of the type is such that a copy into a register
4620 would put it into the wrong part of the register.
4622 Which padding can't be supported depends on the byte endianness.
4624 A value in a register is implicitly padded at the most significant end.
4625 On a big-endian machine, that is the lower end in memory.
4626 So a value padded in memory at the upper end can't go in a register.
4627 For a little-endian machine, the reverse is true. */
4629 bool
4632 tree type;
4633 {
4637 /* If the type has variable size... */
4641 /* If the type is marked as addressable (it is required
4642 to be constructed into the stack)... */
4646 /* If the padding and mode of the type is such that a copy into
4647 a register would put it into the wrong part of the register. */
4655 }