| blob | ad18318627baae4fb51c13c24f571c525817d8d4 |
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. */
43 /* Decide whether a function's arguments should be processed
44 from first to last or from last to first.
46 They should if the stack and args grow in opposite directions, but
47 only if we have push insns. */
49 #ifdef PUSH_ROUNDING
51 #ifndef PUSH_ARGS_REVERSED
52 #if defined (STACK_GROWS_DOWNWARD) != defined (ARGS_GROW_DOWNWARD)
53 #define PUSH_ARGS_REVERSED PUSH_ARGS
54 #endif
55 #endif
57 #endif
59 #ifndef PUSH_ARGS_REVERSED
60 #define PUSH_ARGS_REVERSED 0
61 #endif
63 #ifndef STACK_POINTER_OFFSET
64 #define STACK_POINTER_OFFSET 0
65 #endif
67 /* Like PREFERRED_STACK_BOUNDARY but in units of bytes, not bits. */
68 #define STACK_BYTES (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT)
70 /* Data structure and subroutines used within expand_call. */
72 struct arg_data
73 {
74 /* Tree node for this argument. */
75 tree tree_value;
76 /* Mode for value; TYPE_MODE unless promoted. */
78 /* Current RTL value for argument, or 0 if it isn't precomputed. */
79 rtx value;
80 /* Initially-compute RTL value for argument; only for const functions. */
81 rtx initial_value;
82 /* Register to pass this argument in, 0 if passed on stack, or an
83 PARALLEL if the arg is to be copied into multiple non-contiguous
84 registers. */
85 rtx reg;
86 /* Register to pass this argument in when generating tail call sequence.
87 This is not the same register as for normal calls on machines with
88 register windows. */
89 rtx tail_call_reg;
90 /* If REG was promoted from the actual mode of the argument expression,
91 indicates whether the promotion is sign- or zero-extended. */
93 /* Number of registers to use. 0 means put the whole arg in registers.
94 Also 0 if not passed in registers. */
96 /* Nonzero if argument must be passed on stack.
97 Note that some arguments may be passed on the stack
98 even though pass_on_stack is zero, just because FUNCTION_ARG says so.
99 pass_on_stack identifies arguments that *cannot* go in registers. */
101 /* Some fields packaged up for locate_and_pad_parm. */
103 /* Location on the stack at which parameter should be stored. The store
104 has already been done if STACK == VALUE. */
105 rtx stack;
106 /* Location on the stack of the start of this argument slot. This can
107 differ from STACK if this arg pads downward. This location is known
108 to be aligned to FUNCTION_ARG_BOUNDARY. */
109 rtx stack_slot;
110 /* Place that this stack area has been saved, if needed. */
111 rtx save_area;
112 /* If an argument's alignment does not permit direct copying into registers,
113 copy in smaller-sized pieces into pseudos. These are stored in a
114 block pointed to by this field. The next field says how many
115 word-sized pseudos we made. */
118 };
120 /* A vector of one char per byte of stack space. A byte if nonzero if
121 the corresponding stack location has been used.
122 This vector is used to prevent a function call within an argument from
123 clobbering any stack already set up. */
126 /* Size of STACK_USAGE_MAP. */
129 /* A bitmap of virtual-incoming stack space. Bit is set if the corresponding
130 stack location's tail call argument has been already stored into the stack.
131 This bitmap is used to prevent sibling call optimization if function tries
132 to use parent's incoming argument slots when they have been already
133 overwritten with tail call arguments. */
136 /* stack_arg_under_construction is nonzero when an argument may be
137 initialized with a constructor call (including a C function that
138 returns a BLKmode struct) and expand_call must take special action
139 to make sure the object being constructed does not overlap the
140 argument list for the constructor call. */
149 CUMULATIVE_ARGS *));
169 CUMULATIVE_ARGS *,
189 static int combine_pending_stack_adjustment_and_call
193 #ifdef REG_PARM_STACK_SPACE
196 #endif
197 \f
198 /* If WHICH is 1, return 1 if EXP contains a call to the built-in function
199 `alloca'.
201 If WHICH is 0, return 1 if EXP contains a call to any function.
202 Actually, we only need return 1 if evaluating EXP would require pushing
203 arguments on the stack, but that is too difficult to compute, so we just
204 assume any function call might require the stack. */
208 static int
210 tree exp;
212 {
219 }
221 /* Recursive function to do the work of above function. */
223 static int
225 tree exp;
227 {
233 /* If this code is language-specific, we don't know what it will do. */
238 {
244 && (TYPE_RETURNS_STACK_DEPRESSED
258 {
259 tree tem;
264 }
274 calls_function_save_exprs);
279 {
280 tree local;
281 tree subblock;
289 subblock;
293 }
304 }
306 /* Only expressions, references, and blocks can contain calls. */
316 }
317 \f
318 /* Force FUNEXP into a form suitable for the address of a CALL,
319 and return that as an rtx. Also load the static chain register
320 if FNDECL is a nested function.
322 CALL_FUSAGE points to a variable holding the prospective
323 CALL_INSN_FUNCTION_USAGE information. */
325 rtx
327 rtx funexp;
328 tree fndecl;
332 {
338 /* Get possible static chain value for nested function in C. */
341 /* Make a valid memory address and copy constants thru pseudo-regs,
342 but not for a constant address if -fno-function-cse. */
344 /* If we are using registers for parameters, force the
345 function address into a register now. */
350 {
351 #ifndef NO_FUNCTION_CSE
353 #ifdef NO_RECURSIVE_FUNCTION_CSE
355 #endif
357 #endif
358 }
361 {
366 }
369 }
371 /* Generate instructions to call function FUNEXP,
372 and optionally pop the results.
373 The CALL_INSN is the first insn generated.
375 FNDECL is the declaration node of the function. This is given to the
376 macro RETURN_POPS_ARGS to determine whether this function pops its own args.
378 FUNTYPE is the data type of the function. This is given to the macro
379 RETURN_POPS_ARGS to determine whether this function pops its own args.
380 We used to allow an identifier for library functions, but that doesn't
381 work when the return type is an aggregate type and the calling convention
382 says that the pointer to this aggregate is to be popped by the callee.
384 STACK_SIZE is the number of bytes of arguments on the stack,
385 ROUNDED_STACK_SIZE is that number rounded up to
386 PREFERRED_STACK_BOUNDARY; zero if the size is variable. This is
387 both to put into the call insn and to generate explicit popping
388 code if necessary.
390 STRUCT_VALUE_SIZE is the number of bytes wanted in a structure value.
391 It is zero if this call doesn't want a structure value.
393 NEXT_ARG_REG is the rtx that results from executing
394 FUNCTION_ARG (args_so_far, VOIDmode, void_type_node, 1)
395 just after all the args have had their registers assigned.
396 This could be whatever you like, but normally it is the first
397 arg-register beyond those used for args in this call,
398 or 0 if all the arg-registers are used in this call.
399 It is passed on to `gen_call' so you can put this info in the call insn.
401 VALREG is a hard register in which a value is returned,
402 or 0 if the call does not return a value.
404 OLD_INHIBIT_DEFER_POP is the value that `inhibit_defer_pop' had before
405 the args to this call were processed.
406 We restore `inhibit_defer_pop' to that value.
408 CALL_FUSAGE is either empty or an EXPR_LIST of USE expressions that
409 denote registers used by the called function. */
411 static void
415 rtx funexp;
416 tree fndecl ATTRIBUTE_UNUSED;
417 tree funtype ATTRIBUTE_UNUSED;
418 HOST_WIDE_INT stack_size ATTRIBUTE_UNUSED;
419 HOST_WIDE_INT rounded_stack_size;
420 HOST_WIDE_INT struct_value_size ATTRIBUTE_UNUSED;
421 rtx next_arg_reg ATTRIBUTE_UNUSED;
422 rtx valreg;
424 rtx call_fusage;
427 {
429 rtx call_insn;
432 #if defined (HAVE_call) && defined (HAVE_call_value)
433 rtx struct_value_size_rtx;
435 #endif
437 #ifdef CALL_POPS_ARGS
439 #endif
441 /* Ensure address is valid. SYMBOL_REF is already valid, so no need,
442 and we don't want to load it into a register as an optimization,
443 because prepare_call_address already did it if it should be done. */
447 #if defined (HAVE_sibcall_pop) && defined (HAVE_sibcall_value_pop)
451 {
453 rtx pat;
455 /* If this subroutine pops its own args, record that in the call insn
456 if possible, for the sake of frame pointer elimination. */
462 n_pop);
463 else
469 }
470 else
471 #endif
473 #if defined (HAVE_call_pop) && defined (HAVE_call_value_pop)
474 /* If the target has "call" or "call_value" insns, then prefer them
475 if no arguments are actually popped. If the target does not have
476 "call" or "call_value" insns, then we must use the popping versions
477 even if the call has no arguments to pop. */
478 #if defined (HAVE_call) && defined (HAVE_call_value)
481 #else
483 #endif
484 {
486 rtx pat;
488 /* If this subroutine pops its own args, record that in the call insn
489 if possible, for the sake of frame pointer elimination. */
495 else
501 }
502 else
503 #endif
505 #if defined (HAVE_sibcall) && defined (HAVE_sibcall_value)
508 {
512 rounded_stack_size_rtx,
514 else
517 struct_value_size_rtx));
518 }
519 else
520 #endif
522 #if defined (HAVE_call) && defined (HAVE_call_value)
524 {
529 NULL_RTX));
530 else
533 struct_value_size_rtx));
534 }
535 else
536 #endif
539 /* Find the call we just emitted. */
542 /* Mark memory as used for "pure" function call. */
544 call_fusage
545 = gen_rtx_EXPR_LIST
549 call_fusage);
551 /* Put the register usage information there. */
554 /* If this is a const call, then set the insn's unchanging bit. */
558 /* If this call can't throw, attach a REG_EH_REGION reg note to that
559 effect. */
563 else
574 {
578 }
582 /* Restore this now, so that we do defer pops for this call's args
583 if the context of the call as a whole permits. */
587 {
596 }
599 {
600 /* If returning from the subroutine does not automatically pop the args,
601 we need an instruction to pop them sooner or later.
602 Perhaps do it now; perhaps just record how much space to pop later.
604 If returning from the subroutine does pop the args, indicate that the
605 stack pointer will be changed. */
608 {
610 /* Just pretend we did the pop. */
615 else
617 }
618 }
619 /* When we accumulate outgoing args, we must avoid any stack manipulations.
620 Restore the stack pointer to its original value now. Usually
621 ACCUMULATE_OUTGOING_ARGS targets don't get here, but there are exceptions.
622 On i386 ACCUMULATE_OUTGOING_ARGS can be enabled on demand, and
623 popping variants of functions exist as well.
625 ??? We may optimize similar to defer_pop above, but it is
626 probably not worthwhile.
628 ??? It will be worthwhile to enable combine_stack_adjustments even for
629 such machines. */
632 }
634 /* Determine if the function identified by NAME and FNDECL is one with
635 special properties we wish to know about.
637 For example, if the function might return more than one time (setjmp), then
638 set RETURNS_TWICE to a nonzero value.
640 Similarly set LONGJMP for if the function is in the longjmp family.
642 Set MAY_BE_ALLOCA for any memory allocation function that might allocate
643 space from the stack such as alloca. */
645 static int
647 tree fndecl;
649 {
653 /* Exclude functions not at the file scope, or not `extern',
654 since they are not the magic functions we would otherwise
655 think they are. */
657 {
661 /* We assume that alloca will always be called by name. It
662 makes no sense to pass it as a pointer-to-function to
663 anything that does not understand its behavior. */
672 /* Disregard prefix _, __ or __x. */
674 {
679 else
681 }
684 {
697 }
710 /* Linux specific: __clone. check NAME to insist on the
711 leading underscores, to avoid polluting the ISO / POSIX
712 namespace. */
721 }
723 }
725 /* Return nonzero when tree represent call to longjmp. */
727 int
729 tree fndecl;
730 {
732 }
734 /* Return true when exp contains alloca call. */
735 bool
737 tree exp;
738 {
747 }
749 /* Detect flags (function attributes) from the function decl or type node. */
751 int
753 tree exp;
754 {
759 {
764 {
769 }
771 /* The function exp may have the `malloc' attribute. */
775 /* The function exp may have the `pure' attribute. */
781 }
789 /* Mark if the function returns with the stack pointer depressed. We
790 cannot consider it pure or constant in that case. */
792 {
795 }
798 }
800 /* Precompute all register parameters as described by ARGS, storing values
801 into fields within the ARGS array.
803 NUM_ACTUALS indicates the total number elements in the ARGS array.
805 Set REG_PARM_SEEN if we encounter a register parameter. */
807 static void
812 {
819 {
823 {
830 /* ANSI doesn't require a sequence point here,
831 but PCC has one, so this will avoid some problems. */
833 }
835 /* If the value is a non-legitimate constant, force it into a
836 pseudo now. TLS symbols sometimes need a call to resolve. */
841 /* If we are to promote the function arg to a wider mode,
842 do it now. */
850 /* If the value is expensive, and we are inside an appropriately
851 short loop, put the value into a pseudo and then put the pseudo
852 into the hard reg.
854 For small register classes, also do this if this call uses
855 register parameters. This is to avoid reload conflicts while
856 loading the parameters registers. */
866 }
867 }
869 #ifdef REG_PARM_STACK_SPACE
871 /* The argument list is the property of the called routine and it
872 may clobber it. If the fixed area has been used for previous
873 parameters, we must save and restore it. */
875 static rtx
879 rtx argblock;
882 {
886 /* Compute the boundary of the area that needs to be saved, if any. */
888 #ifdef ARGS_GROW_DOWNWARD
890 #endif
896 {
900 rtx stack_area;
901 rtx save_area;
904 ;
912 /* If we don't have the required alignment, must do this
913 in BLKmode. */
918 #ifdef ARGS_GROW_DOWNWARD
920 #else
922 #endif
926 delta)));
930 {
934 }
935 else
936 {
939 }
942 }
945 }
947 static void
949 rtx save_area;
950 rtx argblock;
953 {
956 rtx stack_area;
958 #ifdef ARGS_GROW_DOWNWARD
960 #else
962 #endif
970 else
973 BLOCK_OP_CALL_PARM);
974 }
977 /* If any elements in ARGS refer to parameters that are to be passed in
978 registers, but not in memory, and whose alignment does not permit a
979 direct copy into registers. Copy the values into a group of pseudos
980 which we will later copy into the appropriate hard registers.
982 Pseudos for each unaligned argument will be stored into the array
983 args[argnum].aligned_regs. The caller is responsible for deallocating
984 the aligned_regs array if it is nonzero. */
986 static void
990 {
998 {
1009 /* Structures smaller than a word are aligned to the least
1010 significant byte (to the right). On a BYTES_BIG_ENDIAN machine,
1011 this means we must skip the empty high order bytes when
1012 calculating the bit offset. */
1018 {
1025 /* There is no need to restrict this code to loading items
1026 in TYPE_ALIGN sized hunks. The bitfield instructions can
1027 load up entire word sized registers efficiently.
1029 ??? This may not be needed anymore.
1030 We use to emit a clobber here but that doesn't let later
1031 passes optimize the instructions we emit. By storing 0 into
1032 the register later passes know the first AND to zero out the
1033 bitfield being set in the register is unnecessary. The store
1034 of 0 will be deleted as will at least the first AND. */
1042 BITS_PER_WORD),
1043 BITS_PER_WORD);
1044 }
1045 }
1046 }
1048 /* Fill in ARGS_SIZE and ARGS array based on the parameters found in
1049 ACTPARMS.
1051 NUM_ACTUALS is the total number of parameters.
1053 N_NAMED_ARGS is the total number of named arguments.
1055 FNDECL is the tree code for the target of this call (if known)
1057 ARGS_SO_FAR holds state needed by the target to know where to place
1058 the next argument.
1060 REG_PARM_STACK_SPACE is the number of bytes of stack space reserved
1061 for arguments which are passed in registers.
1063 OLD_STACK_LEVEL is a pointer to an rtx which olds the old stack level
1064 and may be modified by this routine.
1066 OLD_PENDING_ADJ, MUST_PREALLOCATE and FLAGS are pointers to integer
1067 flags which may may be modified by this routine. */
1069 static void
1074 ecf_flags)
1079 tree actparms;
1080 tree fndecl;
1087 {
1088 /* 1 if scanning parms front to back, -1 if scanning back to front. */
1091 /* Count arg position in order args appear. */
1095 tree p;
1100 /* In this loop, we consider args in the order they are written.
1101 We fill up ARGS from the front or from the back if necessary
1102 so that in any case the first arg to be pushed ends up at the front. */
1105 {
1107 /* In this case, must reverse order of args
1108 so that we compute and push the last arg first. */
1109 }
1110 else
1111 {
1113 }
1115 /* I counts args in order (to be) pushed; ARGPOS counts in order written. */
1117 {
1124 /* Replace erroneous argument with constant zero. */
1128 /* If TYPE is a transparent union, pass things the way we would
1129 pass the first field of the union. We have already verified that
1130 the modes are the same. */
1134 /* Decide where to pass this arg.
1136 args[i].reg is nonzero if all or part is passed in registers.
1138 args[i].partial is nonzero if part but not all is passed in registers,
1139 and the exact value says how many words are passed in registers.
1141 args[i].pass_on_stack is nonzero if the argument must at least be
1142 computed on the stack. It may then be loaded back into registers
1143 if args[i].reg is nonzero.
1145 These decisions are driven by the FUNCTION_... macros and must agree
1146 with those made by function.c. */
1148 /* See if this argument should be passed by invisible reference. */
1151 #ifdef FUNCTION_ARG_PASS_BY_REFERENCE
1154 #endif
1155 )
1156 {
1157 /* If we're compiling a thunk, pass through invisible
1158 references instead of making a copy. */
1160 #ifdef FUNCTION_ARG_CALLEE_COPIES
1163 /* If it's in a register, we must make a copy of it too. */
1164 /* ??? Is this a sufficient test? Is there a better one? */
1168 #endif
1169 )
1170 {
1171 /* C++ uses a TARGET_EXPR to indicate that we want to make a
1172 new object from the argument. If we are passing by
1173 invisible reference, the callee will do that for us, so we
1174 can strip off the TARGET_EXPR. This is not always safe,
1175 but it is safe in the only case where this is a useful
1176 optimization; namely, when the argument is a plain object.
1177 In that case, the frontend is just asking the backend to
1178 make a bitwise copy of the argument. */
1189 }
1191 {
1192 /* In the V3 C++ ABI, parameters are destroyed in the caller.
1193 We implement this by passing the address of the temporary
1194 rather than expanding it into another allocated slot. */
1199 }
1200 else
1201 {
1202 /* We make a copy of the object and pass the address to the
1203 function being called. */
1204 rtx copy;
1210 STACK_CHECK_MAX_VAR_SIZE))))
1211 {
1212 /* This is a variable-sized object. Make space on the stack
1213 for it. */
1217 {
1221 }
1224 allocate_dynamic_stack_space
1227 }
1228 else
1238 }
1239 }
1244 #ifdef PROMOTE_FUNCTION_ARGS
1246 #endif
1253 #ifdef FUNCTION_INCOMING_ARG
1254 /* If this is a sibling call and the machine has register windows, the
1255 register window has to be unwinded before calling the routine, so
1256 arguments have to go into the incoming registers. */
1259 #else
1261 #endif
1263 #ifdef FUNCTION_ARG_PARTIAL_NREGS
1268 #endif
1272 /* If FUNCTION_ARG returned a (parallel [(expr_list (nil) ...) ...]),
1273 it means that we are to pass this arg in the register(s) designated
1274 by the PARALLEL, but also to pass it in the stack. */
1279 /* If this is an addressable type, we must preallocate the stack
1280 since we must evaluate the object into its final location.
1282 If this is to be passed in both registers and the stack, it is simpler
1283 to preallocate. */
1288 /* If this is an addressable type, we cannot pre-evaluate it. Thus,
1289 we cannot consider this function call constant. */
1293 /* Compute the stack-size of this argument. */
1298 #ifdef STACK_PARMS_IN_REG_PARM_AREA
1300 #else
1302 #endif
1306 /* Update ARGS_SIZE, the total stack space for args so far. */
1312 /* Increment ARGS_SO_FAR, which has info about which arg-registers
1313 have been used, etc. */
1317 }
1318 }
1320 /* Update ARGS_SIZE to contain the total size for the argument block.
1321 Return the original constant component of the argument block's size.
1323 REG_PARM_STACK_SPACE holds the number of bytes of stack space reserved
1324 for arguments passed in registers. */
1326 static int
1328 preferred_stack_boundary)
1332 {
1335 /* For accumulate outgoing args mode we don't need to align, since the frame
1336 will be already aligned. Align to STACK_BOUNDARY in order to prevent
1337 backends from generating misaligned frame sizes. */
1341 /* Compute the actual size of the argument block required. The variable
1342 and constant sizes must be combined, the size may have to be rounded,
1343 and there may be a minimum required size. */
1346 {
1352 {
1353 /* We don't handle this case yet. To handle it correctly we have
1354 to add the delta, round and subtract the delta.
1355 Currently no machine description requires this support. */
1359 }
1362 {
1363 args_size->var
1367 #ifndef OUTGOING_REG_PARM_STACK_SPACE
1368 /* The area corresponding to register parameters is not to count in
1369 the size of the block we need. So make the adjustment. */
1370 args_size->var
1373 #endif
1374 }
1375 }
1376 else
1377 {
1382 + stack_pointer_delta
1384 / preferred_stack_boundary
1389 reg_parm_stack_space);
1391 #ifdef MAYBE_REG_PARM_STACK_SPACE
1394 #endif
1396 #ifndef OUTGOING_REG_PARM_STACK_SPACE
1398 #endif
1399 }
1401 }
1403 /* Precompute parameters as needed for a function call.
1405 FLAGS is mask of ECF_* constants.
1407 NUM_ACTUALS is the number of arguments.
1409 ARGS is an array containing information for each argument; this
1410 routine fills in the INITIAL_VALUE and VALUE fields for each
1411 precomputed argument. */
1413 static void
1418 {
1421 /* If this function call is cse'able, precompute all the parameters.
1422 Note that if the parameter is constructed into a temporary, this will
1423 cause an additional copy because the parameter will be constructed
1424 into a temporary location and then copied into the outgoing arguments.
1425 If a parameter contains a call to alloca and this function uses the
1426 stack, precompute the parameter. */
1428 /* If we preallocated the stack space, and some arguments must be passed
1429 on the stack, then we must precompute any parameter which contains a
1430 function call which will store arguments on the stack.
1431 Otherwise, evaluating the parameter may clobber previous parameters
1432 which have already been stored into the stack. (we have code to avoid
1433 such case by saving the outgoing stack arguments, but it results in
1434 worse code) */
1439 {
1442 /* If this is an addressable type, we cannot pre-evaluate it. */
1449 /* ANSI doesn't require a sequence point here,
1450 but PCC has one, so this will avoid some problems. */
1458 {
1462 #ifdef PROMOTE_FOR_CALL_ONLY
1463 /* CSE will replace this only if it contains args[i].value
1464 pseudo, so convert it down to the declared mode using
1465 a SUBREG. */
1468 {
1474 }
1475 #endif
1476 }
1477 }
1478 }
1480 /* Given the current state of MUST_PREALLOCATE and information about
1481 arguments to a function call in NUM_ACTUALS, ARGS and ARGS_SIZE,
1482 compute and return the final value for MUST_PREALLOCATE. */
1484 static int
1490 {
1491 /* See if we have or want to preallocate stack space.
1493 If we would have to push a partially-in-regs parm
1494 before other stack parms, preallocate stack space instead.
1496 If the size of some parm is not a multiple of the required stack
1497 alignment, we must preallocate.
1499 If the total size of arguments that would otherwise create a copy in
1500 a temporary (such as a CALL) is more than half the total argument list
1501 size, preallocation is faster.
1503 Another reason to preallocate is if we have a machine (like the m88k)
1504 where stack alignment is required to be maintained between every
1505 pair of insns, not just when the call is made. However, we assume here
1506 that such machines either do not have push insns (and hence preallocation
1507 would occur anyway) or the problem is taken care of with
1508 PUSH_ROUNDING. */
1511 {
1517 {
1528 copy_to_evaluate_size
1530 }
1535 }
1537 }
1539 /* If we preallocated stack space, compute the address of each argument
1540 and store it into the ARGS array.
1542 We need not ensure it is a valid memory address here; it will be
1543 validized when it is used.
1545 ARGBLOCK is an rtx for the address of the outgoing arguments. */
1547 static void
1550 rtx argblock;
1552 {
1554 {
1562 {
1565 rtx addr;
1567 /* Skip this parm if it will not be passed on the stack. */
1573 else
1584 else
1593 /* Function incoming arguments may overlap with sibling call
1594 outgoing arguments and we cannot allow reordering of reads
1595 from function arguments with stores to outgoing arguments
1596 of sibling calls. */
1599 }
1600 }
1601 }
1603 /* Given a FNDECL and EXP, return an rtx suitable for use as a target address
1604 in a call instruction.
1606 FNDECL is the tree node for the target function. For an indirect call
1607 FNDECL will be NULL_TREE.
1609 ADDR is the operand 0 of CALL_EXPR for this call. */
1611 static rtx
1613 tree fndecl;
1614 tree addr;
1615 {
1616 rtx funexp;
1618 /* Get the function to call, in the form of RTL. */
1620 {
1621 /* If this is the first use of the function, see if we need to
1622 make an external definition for it. */
1624 {
1627 }
1629 /* Get a SYMBOL_REF rtx for the function address. */
1631 }
1632 else
1633 /* Generate an rtx (probably a pseudo-register) for the address. */
1634 {
1639 }
1641 }
1643 /* Do the register loads required for any wholly-register parms or any
1644 parms which are passed both on the stack and in a register. Their
1645 expressions were already evaluated.
1647 Mark all register-parms as living through the call, putting these USE
1648 insns in the CALL_INSN_FUNCTION_USAGE field.
1650 When IS_SIBCALL, perform the check_sibcall_overlap_argument_overlap
1651 checking, setting *SIBCALL_FAILURE if appropriate. */
1653 static void
1662 {
1665 #ifdef LOAD_ARGS_REVERSED
1667 #else
1669 #endif
1670 {
1677 {
1679 /* Set to non-negative if must move a word at a time, even if just
1680 one word (e.g, partial == 1 && mode == DFmode). Set to -1 if
1681 we just use a normal move insn. This value can be zero if the
1682 argument is a zero size structure with no fields. */
1689 /* Handle calls that pass values in multiple non-contiguous
1690 locations. The Irix 6 ABI has examples of this. */
1696 /* If simple case, just do move. If normal partial, store_one_arg
1697 has already loaded the register for us. In all other cases,
1698 load the register(s) from memory. */
1703 /* If we have pre-computed the values to put in the registers in
1704 the case of non-aligned structures, copy them in now. */
1716 /* When a parameter is a block, and perhaps in other cases, it is
1717 possible that it did a load from an argument slot that was
1718 already clobbered. */
1723 /* Handle calls that pass values in multiple non-contiguous
1724 locations. The Irix 6 ABI has examples of this. */
1729 else
1731 }
1732 }
1733 }
1735 /* Try to integrate function. See expand_inline_function for documentation
1736 about the parameters. */
1738 static rtx
1740 tree fndecl;
1741 tree actparms;
1742 rtx target;
1744 tree type;
1745 rtx structure_value_addr;
1746 {
1747 rtx temp;
1748 rtx before_call;
1753 #ifdef REG_PARM_STACK_SPACE
1754 #ifdef MAYBE_REG_PARM_STACK_SPACE
1756 #else
1758 #endif
1759 #endif
1767 structure_value_addr);
1771 /* If inlining succeeded, return. */
1773 {
1775 {
1776 /* If the outgoing argument list must be preserved, push
1777 the stack before executing the inlined function if it
1778 makes any calls. */
1784 ;
1787 {
1788 rtx first_insn
1792 /* Look for a call in the inline function code.
1793 If DECL_SAVED_INSNS (fndecl)->outgoing_args_size is
1794 nonzero then there is a call and it is not necessary
1795 to scan the insns. */
1803 {
1804 /* Reserve enough stack space so that the largest
1805 argument list of any function call in the inline
1806 function does not overlap the argument list being
1807 evaluated. This is usually an overestimate because
1808 allocate_dynamic_stack_space reserves space for an
1809 outgoing argument list in addition to the requested
1810 space, but there is no way to ask for stack space such
1811 that an argument list of a certain length can be
1812 safely constructed.
1814 Add the stack space reserved for register arguments, if
1815 any, in the inline function. What is really needed is the
1816 largest value of reg_parm_stack_space in the inline
1817 function, but that is not available. Using the current
1818 value of reg_parm_stack_space is wrong, but gives
1819 correct results on all supported machines. */
1832 }
1833 }
1834 }
1836 /* If the result is equivalent to TARGET, return TARGET to simplify
1837 checks in store_expr. They can be equivalent but not equal in the
1838 case of a function that returns BLKmode. */
1842 }
1844 /* If inlining failed, mark FNDECL as needing to be compiled
1845 separately after all. If function was declared inline,
1846 give a warning. */
1849 {
1852 }
1855 }
1857 /* We need to pop PENDING_STACK_ADJUST bytes. But, if the arguments
1858 wouldn't fill up an even multiple of PREFERRED_UNIT_STACK_BOUNDARY
1859 bytes, then we would need to push some additional bytes to pad the
1860 arguments. So, we compute an adjust to the stack pointer for an
1861 amount that will leave the stack under-aligned by UNADJUSTED_ARGS_SIZE
1862 bytes. Then, when the arguments are pushed the stack will be perfectly
1863 aligned. ARGS_SIZE->CONSTANT is set to the number of bytes that should
1864 be popped after the call. Returns the adjustment. */
1866 static int
1868 args_size,
1869 preferred_unit_stack_boundary)
1873 {
1874 /* The number of bytes to pop so that the stack will be
1875 under-aligned by UNADJUSTED_ARGS_SIZE bytes. */
1876 HOST_WIDE_INT adjustment;
1877 /* The alignment of the stack after the arguments are pushed, if we
1878 just pushed the arguments without adjust the stack here. */
1879 HOST_WIDE_INT unadjusted_alignment;
1881 unadjusted_alignment
1885 /* We want to get rid of as many of the PENDING_STACK_ADJUST bytes
1886 as possible -- leaving just enough left to cancel out the
1887 UNADJUSTED_ALIGNMENT. In other words, we want to ensure that the
1888 PENDING_STACK_ADJUST is non-negative, and congruent to
1889 -UNADJUSTED_ALIGNMENT modulo the PREFERRED_UNIT_STACK_BOUNDARY. */
1891 /* Begin by trying to pop all the bytes. */
1892 unadjusted_alignment
1893 = (unadjusted_alignment
1896 /* Push enough additional bytes that the stack will be aligned
1897 after the arguments are pushed. */
1899 {
1902 else
1904 }
1906 /* Now, sets ARGS_SIZE->CONSTANT so that we pop the right number of
1907 bytes after the call. The right number is the entire
1908 PENDING_STACK_ADJUST less our ADJUSTMENT plus the amount required
1909 by the arguments in the first place. */
1910 args_size->constant
1914 }
1916 /* Scan X expression if it does not dereference any argument slots
1917 we already clobbered by tail call arguments (as noted in stored_args_map
1918 bitmap).
1919 Return nonzero if X expression dereferences such argument slots,
1920 zero otherwise. */
1922 static int
1924 rtx x;
1925 {
1926 RTX_CODE code;
1937 {
1942 current_function_internal_arg_pointer
1945 else
1948 #ifdef ARGS_GROW_DOWNWARD
1950 #endif
1958 }
1960 /* Scan all subexpressions. */
1963 {
1965 {
1968 }
1970 {
1974 }
1975 }
1977 }
1979 /* Scan sequence after INSN if it does not dereference any argument slots
1980 we already clobbered by tail call arguments (as noted in stored_args_map
1981 bitmap). If MARK_STORED_ARGS_MAP, add stack slots for ARG to
1982 stored_args_map bitmap afterwards (when ARG is a register MARK_STORED_ARGS_MAP
1983 should be 0). Return nonzero if sequence after INSN dereferences such argument
1984 slots, zero otherwise. */
1986 static int
1988 rtx insn;
1991 {
1996 else
2005 {
2006 #ifdef ARGS_GROW_DOWNWARD
2008 #else
2010 #endif
2014 }
2016 }
2018 static tree
2020 tree t;
2021 {
2023 {
2032 {
2038 }
2043 }
2045 }
2047 /* Generate all the code for a function call
2048 and return an rtx for its value.
2049 Store the value in TARGET (specified as an rtx) if convenient.
2050 If the value is stored in TARGET then TARGET is returned.
2051 If IGNORE is nonzero, then we ignore the value of the function call. */
2053 rtx
2055 tree exp;
2056 rtx target;
2058 {
2059 /* Nonzero if we are currently expanding a call. */
2062 /* List of actual parameters. */
2064 /* RTX for the function to be called. */
2065 rtx funexp;
2066 /* Sequence of insns to perform a tail recursive "call". */
2068 /* Sequence of insns to perform a normal "call". */
2070 /* Sequence of insns to perform a tail recursive "call". */
2072 /* Data type of the function. */
2073 tree funtype;
2074 tree type_arg_types;
2075 /* Declaration of the function being called,
2076 or 0 if the function is computed (not known by name). */
2078 rtx insn;
2083 /* Register in which non-BLKmode value will be returned,
2084 or 0 if no value or if value is BLKmode. */
2085 rtx valreg;
2086 /* Address where we should return a BLKmode value;
2087 0 if value not BLKmode. */
2089 /* Nonzero if that address is being passed by treating it as
2090 an extra, implicit first parameter. Otherwise,
2091 it is passed by being copied directly into struct_value_rtx. */
2093 /* Size of aggregate value wanted, or zero if none wanted
2094 or if we are using the non-reentrant PCC calling convention
2095 or expecting the value in registers. */
2097 /* Nonzero if called function returns an aggregate in memory PCC style,
2098 by returning the address of where to find it. */
2101 /* Number of actual parameters in this call, including struct value addr. */
2103 /* Number of named args. Args after this are anonymous ones
2104 and they must all go on the stack. */
2107 /* Vector of information about each argument.
2108 Arguments are numbered in the order they will be pushed,
2109 not the order they are written. */
2112 /* Total size in bytes of all the stack-parms scanned so far. */
2115 /* Size of arguments before any adjustments (such as rounding). */
2117 /* Data on reg parms scanned so far. */
2118 CUMULATIVE_ARGS args_so_far;
2119 /* Nonzero if a reg parm has been scanned. */
2121 /* Nonzero if this is an indirect function call. */
2123 /* Nonzero if we must avoid push-insns in the args for this call.
2124 If stack space is allocated for register parameters, but not by the
2125 caller, then it is preallocated in the fixed part of the stack frame.
2126 So the entire argument block must then be preallocated (i.e., we
2127 ignore PUSH_ROUNDING in that case). */
2131 /* Size of the stack reserved for parameter registers. */
2134 /* Address of space preallocated for stack parms
2135 (on machines that lack push insns), or 0 if space not preallocated. */
2138 /* Mask of ECF_ flags. */
2140 /* Nonzero if this is a call to an inline function. */
2142 #ifdef REG_PARM_STACK_SPACE
2143 /* Define the boundary of the register parm stack space that needs to be
2144 saved, if any. */
2147 #endif
2154 /* State variables to track stack modifications. */
2160 /* Some stack pointer alterations we make are performed via
2161 allocate_dynamic_stack_space. This modifies the stack_pointer_delta,
2162 which we then also need to save/restore along the way. */
2165 rtx call_fusage;
2169 /* The alignment of the stack, in bits. */
2170 HOST_WIDE_INT preferred_stack_boundary;
2171 /* The alignment of the stack, in bytes. */
2172 HOST_WIDE_INT preferred_unit_stack_boundary;
2174 /* See if this is "nothrow" function call. */
2178 /* See if we can find a DECL-node for the actual function.
2179 As a result, decide whether this is a call to an integrable function. */
2183 {
2191 {
2192 /* In case this function later becomes inlinable,
2193 record that there was already a non-inline call to it.
2195 Use abstraction instead of setting TREE_ADDRESSABLE
2196 directly. */
2199 {
2202 }
2204 }
2207 }
2209 /* If we don't have specific function to call, see if we have a
2210 attributes set in the type. */
2211 else
2214 /* Warn if this value is an aggregate type,
2215 regardless of which calling convention we are using for it. */
2219 /* If the result of a pure or const function call is ignored (or void),
2220 and none of its arguments are volatile, we can avoid expanding the
2221 call and just evaluate the arguments for side-effects. */
2225 {
2227 tree arg;
2231 {
2234 }
2237 {
2242 }
2243 }
2245 #ifdef REG_PARM_STACK_SPACE
2246 #ifdef MAYBE_REG_PARM_STACK_SPACE
2248 #else
2250 #endif
2251 #endif
2253 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2256 #endif
2258 /* Set up a place to return a structure. */
2260 /* Cater to broken compilers. */
2262 {
2263 /* This call returns a big structure. */
2266 #ifdef PCC_STATIC_STRUCT_RETURN
2267 {
2269 /* Easier than making that case work right. */
2271 {
2272 /* In case this is a static function, note that it has been
2273 used. */
2277 }
2278 }
2280 {
2284 {
2285 /* The structure value address arg is already in actparms.
2286 Pull it out. It might be nice to just leave it there, but
2287 we need to set structure_value_addr. */
2292 }
2295 else
2296 {
2297 /* For variable-sized objects, we must be called with a target
2298 specified. If we were to allocate space on the stack here,
2299 we would have no way of knowing when to free it. */
2305 }
2306 }
2308 }
2310 /* If called function is inline, try to integrate it. */
2313 {
2316 structure_value_addr);
2319 }
2321 /* Figure out the amount to which the stack should be aligned. */
2324 {
2328 }
2330 /* Operand 0 is a pointer-to-function; get the type of the function. */
2336 /* Munge the tree to split complex arguments into their imaginary
2337 and real parts. */
2339 {
2342 }
2343 else
2346 /* See if this is a call to a function that can return more than once
2347 or a call to longjmp or malloc. */
2353 /* If struct_value_rtx is 0, it means pass the address
2354 as if it were an extra parameter. */
2356 {
2357 /* If structure_value_addr is a REG other than
2358 virtual_outgoing_args_rtx, we can use always use it. If it
2359 is not a REG, we must always copy it into a register.
2360 If it is virtual_outgoing_args_rtx, we must copy it to another
2361 register in some cases. */
2363 || (ACCUMULATE_OUTGOING_ARGS
2364 && stack_arg_under_construction
2369 actparms
2372 temp),
2373 actparms);
2375 }
2377 /* Count the arguments and set NUM_ACTUALS. */
2379 num_actuals++;
2381 /* Compute number of named args.
2382 Normally, don't include the last named arg if anonymous args follow.
2383 We do include the last named arg if STRICT_ARGUMENT_NAMING is nonzero.
2384 (If no anonymous args follow, the result of list_length is actually
2385 one too large. This is harmless.)
2387 If PRETEND_OUTGOING_VARARGS_NAMED is set and STRICT_ARGUMENT_NAMING is
2388 zero, this machine will be able to place unnamed args that were
2389 passed in registers into the stack. So treat all args as named.
2390 This allows the insns emitting for a specific argument list to be
2391 independent of the function declaration.
2393 If PRETEND_OUTGOING_VARARGS_NAMED is not set, we do not have any
2394 reliable way to pass unnamed args in registers, so we must force
2395 them into memory. */
2400 n_named_args
2402 /* Don't include the last named arg. */
2404 /* Count the struct value address, if it is passed as a parm. */
2406 else
2407 /* If we know nothing, treat all args as named. */
2410 /* Start updating where the next arg would go.
2412 On some machines (such as the PA) indirect calls have a different
2413 calling convention than normal calls. The last argument in
2414 INIT_CUMULATIVE_ARGS tells the backend if this is an indirect call
2415 or not. */
2418 /* Make a vector to hold all the information about each arg. */
2422 /* Build up entries in the ARGS array, compute the size of the
2423 arguments into ARGS_SIZE, etc. */
2431 {
2432 /* If this function requires a variable-sized argument list, don't
2433 try to make a cse'able block for this call. We may be able to
2434 do this eventually, but it is too complicated to keep track of
2435 what insns go in the cse'able block and which don't. */
2439 }
2441 /* Now make final decision about preallocating stack space. */
2446 /* If the structure value address will reference the stack pointer, we
2447 must stabilize it. We don't need to do this if we know that we are
2448 not going to adjust the stack pointer in processing this call. */
2453 structure_value_addr))
2458 /* Tail calls can make things harder to debug, and we're traditionally
2459 pushed these optimizations into -O2. Don't try if we're already
2460 expanding a call, as that means we're an argument. Don't try if
2461 there's cleanups, as we know there's code to follow the call.
2463 If rtx_equal_function_value_matters is false, that means we've
2464 finished with regular parsing. Which means that some of the
2465 machinery we use to generate tail-calls is no longer in place.
2466 This is most often true of sjlj-exceptions, which we couldn't
2467 tail-call to anyway. */
2470 || !flag_optimize_sibling_calls
2471 || !rtx_equal_function_value_matters
2476 /* Tail recursion fails, when we are not dealing with recursive calls. */
2482 /* Rest of purposes for tail call optimizations to fail. */
2484 #ifdef HAVE_sibcall_epilogue
2485 !HAVE_sibcall_epilogue
2486 #else
2487 1
2488 #endif
2489 || !try_tail_call
2490 /* Doing sibling call optimization needs some work, since
2491 structure_value_addr can be allocated on the stack.
2492 It does not seem worth the effort since few optimizable
2493 sibling calls will return a structure. */
2495 /* Check whether the target is able to optimize the call
2496 into a sibcall. */
2498 /* Functions that do not return exactly once may not be sibcall
2499 optimized. */
2502 /* If the called function is nested in the current one, it might access
2503 some of the caller's arguments, but could clobber them beforehand if
2504 the argument areas are shared. */
2506 /* If this function requires more stack slots than the current
2507 function, we cannot change it into a sibling call. */
2509 /* If the callee pops its own arguments, then it must pop exactly
2510 the same number of arguments as the current function. */
2514 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 }
2622 /* Ensure current function's preferred stack boundary is at least
2623 what we need. We don't have to increase alignment for recursive
2624 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 {
2754 /* stack_arg_under_construction says whether a stack arg is
2755 being constructed at the old stack level. Pushing the stack
2756 gets a clean outgoing argument block. */
2759 }
2761 }
2762 else
2763 {
2764 /* Note that we must go through the motions of allocating an argument
2765 block even if the size is zero because we may be storing args
2766 in the area reserved for register arguments, which may be part of
2767 the stack frame. */
2771 /* Store the maximum argument space used. It will be pushed by
2772 the prologue (if ACCUMULATE_OUTGOING_ARGS, or stack overflow
2773 checking). */
2779 {
2781 {
2782 /* Since the stack pointer will never be pushed, it is
2783 possible for the evaluation of a parm to clobber
2784 something we have already written to the stack.
2785 Since most function calls on RISC machines do not use
2786 the stack, this is uncommon, but must work correctly.
2788 Therefore, we save any area of the stack that was already
2789 written and that we are using. Here we set up to do this
2790 by making a new stack usage map from the old one. The
2791 actual save will be done by store_one_arg.
2793 Another approach might be to try to reorder the argument
2794 evaluations to avoid this conflicting stack usage. */
2796 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2797 /* Since we will be writing into the entire argument area,
2798 the map must be allocated for its entire size, not just
2799 the part that is the responsibility of the caller. */
2801 #endif
2803 #ifdef ARGS_GROW_DOWNWARD
2806 #else
2808 needed);
2809 #endif
2810 stack_usage_map
2815 initial_highest_arg_in_use);
2819 (highest_outgoing_arg_in_use
2823 /* The address of the outgoing argument list must not be
2824 copied to a register here, because argblock would be left
2825 pointing to the wrong place after the call to
2826 allocate_dynamic_stack_space below. */
2829 }
2830 else
2831 {
2833 {
2834 /* Try to reuse some or all of the pending_stack_adjust
2835 to get this space. */
2836 needed
2837 = (combine_pending_stack_adjustment_and_call
2840 preferred_unit_stack_boundary));
2842 /* combine_pending_stack_adjustment_and_call computes
2843 an adjustment before the arguments are allocated.
2844 Account for them and see whether or not the stack
2845 needs to go up or down. */
2849 {
2850 /* We're releasing stack space. */
2851 /* ??? We can avoid any adjustment at all if we're
2852 already aligned. FIXME. */
2856 }
2857 else
2858 /* We need to allocate space. We'll do that in
2859 push_block below. */
2861 }
2863 /* Special case this because overhead of `push_block' in
2864 this case is non-trivial. */
2867 else
2868 {
2870 #ifdef ARGS_GROW_DOWNWARD
2872 #endif
2873 }
2875 /* We only really need to call `copy_to_reg' in the case
2876 where push insns are going to be used to pass ARGBLOCK
2877 to a function call in ARGS. In that case, the stack
2878 pointer changes value from the allocation point to the
2879 call point, and hence the value of
2880 VIRTUAL_OUTGOING_ARGS_RTX changes as well. But might
2881 as well always do it. */
2883 }
2884 }
2885 }
2888 {
2889 /* The save/restore code in store_one_arg handles all
2890 cases except one: a constructor call (including a C
2891 function returning a BLKmode struct) to initialize
2892 an argument. */
2894 {
2895 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2898 #else
2900 #endif
2902 {
2904 NULL_RTX);
2908 /* stack_arg_under_construction says whether a stack
2909 arg is being constructed at the old stack level.
2910 Pushing the stack gets a clean outgoing argument
2911 block. */
2912 old_stack_arg_under_construction
2915 /* Make a new map for the new argument list. */
2920 }
2922 BITS_PER_UNIT);
2923 }
2925 /* If argument evaluation might modify the stack pointer,
2926 copy the address of the argument list to a register. */
2929 {
2932 }
2933 }
2937 /* If we push args individually in reverse order, perform stack alignment
2938 before the first push (the last arg). */
2941 {
2942 /* When the stack adjustment is pending, we get better code
2943 by combining the adjustments. */
2947 {
2948 pending_stack_adjust
2949 = (combine_pending_stack_adjustment_and_call
2952 preferred_unit_stack_boundary));
2954 }
2958 }
2959 /* Now that the stack is properly aligned, pops can't safely
2960 be deferred during the evaluation of the arguments. */
2961 NO_DEFER_POP;
2965 /* Figure out the register where the value, if any, will come back. */
2969 {
2973 else
2975 }
2977 /* Precompute all register parameters. It isn't safe to compute anything
2978 once we have started filling any specific hard regs. */
2981 #ifdef REG_PARM_STACK_SPACE
2982 /* Save the fixed argument area if it's part of the caller's frame and
2983 is clobbered by argument setup for this call. */
2987 #endif
2989 /* Now store (and compute if necessary) all non-register parms.
2990 These come before register parms, since they can require block-moves,
2991 which could clobber the registers used for register parms.
2992 Parms which have partial registers are not stored here,
2993 but we do preallocate space here if they want that. */
2997 {
3002 reg_parm_stack_space)
3007 }
3009 /* If we have a parm that is passed in registers but not in memory
3010 and whose alignment does not permit a direct copy into registers,
3011 make a group of pseudos that correspond to each register that we
3012 will later fill. */
3016 /* Now store any partially-in-registers parm.
3017 This is the last place a block-move can happen. */
3021 {
3026 reg_parm_stack_space)
3031 }
3033 /* If we pushed args in forward order, perform stack alignment
3034 after pushing the last arg. */
3039 /* If register arguments require space on the stack and stack space
3040 was not preallocated, allocate stack space here for arguments
3041 passed in registers. */
3042 #ifdef OUTGOING_REG_PARM_STACK_SPACE
3046 #endif
3048 /* Pass the function the address in which to return a
3049 structure value. */
3051 {
3052 #ifdef POINTERS_EXTEND_UNSIGNED
3054 structure_value_addr = convert_memory_address
3056 #endif
3060 NULL_RTX)));
3064 }
3072 /* Perform postincrements before actually calling the function. */
3075 /* Save a pointer to the last insn before the call, so that we can
3076 later safely search backwards to find the CALL_INSN. */
3079 /* Set up next argument register. For sibling calls on machines
3080 with register windows this should be the incoming register. */
3081 #ifdef FUNCTION_INCOMING_ARG
3085 else
3086 #endif
3090 /* All arguments and registers used for the call must be set up by
3091 now! */
3093 /* Stack must be properly aligned now. */
3097 /* Generate the actual call instruction. */
3103 /* If call is cse'able, make appropriate pair of reg-notes around it.
3104 Test valreg so we don't crash; may safely ignore `const'
3105 if return type is void. Disable for PARALLEL return values, because
3106 we have no way to move such values into a pseudo register. */
3108 {
3109 rtx insns;
3112 {
3116 }
3117 else
3118 {
3122 /* Mark the return value as a pointer if needed. */
3127 /* Construct an "equal form" for the value which mentions all the
3128 arguments in order as well as the function name. */
3142 note);
3147 }
3148 }
3150 {
3154 /* The return value from a malloc-like function is a pointer. */
3160 /* The return value from a malloc-like function can not alias
3161 anything else. */
3166 /* Write out the sequence. */
3171 }
3173 /* For calls to `setjmp', etc., inform flow.c it should complain
3174 if nonvolatile values are live. For functions that cannot return,
3175 inform flow that control does not fall through. */
3178 {
3179 /* The barrier must be emitted
3180 immediately after the CALL_INSN. Some ports emit more
3181 than just a CALL_INSN above, so we must search for it here. */
3185 {
3187 /* There was no CALL_INSN? */
3190 }
3193 }
3198 /* If value type not void, return an rtx for the value. */
3200 /* If there are cleanups to be called, don't use a hard reg as target.
3201 We need to double check this and see if it matters anymore. */
3203 {
3208 }
3214 {
3216 {
3217 target
3220 structure_value_addr));
3222 }
3223 }
3225 {
3226 /* This is the special C++ case where we need to
3227 know what the true target was. We take care to
3228 never use this value more than once in one expression. */
3232 }
3233 /* Handle calls that return values in multiple non-contiguous locations.
3234 The Irix 6 ABI has examples of this. */
3236 {
3238 {
3239 /* This will only be assigned once, so it can be readonly. */
3246 }
3252 /* We can not support sibling calls for this case. */
3254 }
3258 {
3259 /* TARGET and VALREG cannot be equal at this point because the
3260 latter would not have REG_FUNCTION_VALUE_P true, while the
3261 former would if it were referring to the same register.
3263 If they refer to the same register, this move will be a no-op,
3264 except when function inlining is being done. */
3267 /* If we are setting a MEM, this code must be executed. Since it is
3268 emitted after the call insn, sibcall optimization cannot be
3269 performed in that case. */
3272 }
3274 {
3277 /* We can not support sibling calls for this case. */
3279 }
3280 else
3283 #ifdef PROMOTE_FUNCTION_RETURN
3284 /* If we promoted this return value, make the proper SUBREG. TARGET
3285 might be const0_rtx here, so be careful. */
3289 {
3294 /* If we don't promote as expected, something is wrong. */
3302 {
3309 }
3313 }
3314 #endif
3316 /* If size of args is variable or this was a constructor call for a stack
3317 argument, restore saved stack-pointer value. */
3320 {
3328 }
3330 {
3331 #ifdef REG_PARM_STACK_SPACE
3335 #endif
3337 /* If we saved any argument areas, restore them. */
3340 {
3342 rtx stack_area
3349 else
3352 BLOCK_OP_CALL_PARM);
3353 }
3357 }
3359 /* If this was alloca, record the new stack level for nonlocal gotos.
3360 Check for the handler slots since we might not have a save area
3361 for non-local gotos. */
3366 /* Free up storage we no longer need. */
3372 {
3373 /* Undo the fake expand_start_target_temps we did earlier. If
3374 there had been any cleanups created, we've already set
3375 sibcall_failure. */
3377 }
3379 /* If this function is returning into a memory location marked as
3380 readonly, it means it is initializing that location. We normally treat
3381 functions as not clobbering such locations, so we need to specify that
3382 this one does. We do this by adding the appropriate CLOBBER to the
3383 CALL_INSN function usage list. This cannot be done by emitting a
3384 standalone CLOBBER after the call because the latter would be ignored
3385 by at least the delay slot scheduling pass. We do this now instead of
3386 adding to call_fusage before the call to emit_call_1 because TARGET
3387 may be modified in the meantime. */
3390 add_function_usage_to
3393 NULL_RTX));
3399 {
3402 /* Restore the pending stack adjustment now that we have
3403 finished generating the sibling call sequence. */
3408 /* Prepare arg structure for next iteration. */
3410 {
3414 }
3417 }
3418 else
3419 {
3422 /* Verify that we've deallocated all the stack we used. */
3426 }
3428 /* If something prevents making this a sibling call,
3429 zero out the sequence. */
3432 }
3434 /* The function optimize_sibling_and_tail_recursive_calls doesn't
3435 handle CALL_PLACEHOLDERs inside other CALL_PLACEHOLDERs. This
3436 can happen if the arguments to this function call an inline
3437 function who's expansion contains another CALL_PLACEHOLDER.
3439 If there are any C_Ps in any of these sequences, replace them
3440 with their normal call. */
3457 /* If this was a potential tail recursion site, then emit a
3458 CALL_PLACEHOLDER with the normal and the tail recursion streams.
3459 One of them will be selected later. */
3461 {
3462 /* The tail recursion label must be kept around. We could expose
3463 its use in the CALL_PLACEHOLDER, but that creates unwanted edges
3464 and makes determining true tail recursion sites difficult.
3466 So we set LABEL_PRESERVE_P here, then clear it when we select
3467 one of the call sequences after rtl generation is complete. */
3471 tail_call_insns,
3472 tail_recursion_insns,
3473 tail_recursion_label));
3474 }
3475 else
3478 currently_expanding_call--;
3480 /* If this function returns with the stack pointer depressed, ensure
3481 this block saves and restores the stack pointer, show it was
3482 changed, and adjust for any outgoing arg space. */
3484 {
3489 }
3492 }
3494 /* Traverse an argument list in VALUES and expand all complex
3495 arguments into their components. */
3496 tree
3498 {
3499 tree p;
3504 {
3506 tree complex_type;
3513 {
3514 tree subtype;
3528 /* Skip the newly created node. */
3530 }
3531 }
3534 }
3536 /* Traverse a list of TYPES and expand all complex types into their
3537 components. */
3538 tree
3540 {
3541 tree p;
3546 {
3550 {
3553 /* Rewrite complex type with component type. */
3557 /* Add another component type for the imaginary part. */
3562 /* Skip the newly created node. */
3564 }
3565 }
3568 }
3569 \f
3570 /* Output a library call to function FUN (a SYMBOL_REF rtx).
3571 The RETVAL parameter specifies whether return value needs to be saved, other
3572 parameters are documented in the emit_library_call function below. */
3574 static rtx
3577 rtx orgfun;
3578 rtx value;
3583 {
3584 /* Total size in bytes of all the stack-parms scanned so far. */
3586 /* Size of arguments before any adjustments (such as rounding). */
3589 rtx fun;
3593 CUMULATIVE_ARGS args_so_far;
3594 struct arg
3595 {
3596 rtx value;
3598 rtx reg;
3601 rtx save_area;
3602 };
3607 rtx valreg;
3613 rtx before_call;
3616 #ifdef REG_PARM_STACK_SPACE
3617 /* Define the boundary of the register parm stack space that needs to be
3618 save, if any. */
3621 #endif
3623 /* Size of the stack reserved for parameter registers. */
3627 #ifdef REG_PARM_STACK_SPACE
3628 #ifdef MAYBE_REG_PARM_STACK_SPACE
3630 #else
3632 #endif
3633 #endif
3635 /* By default, library functions can not throw. */
3639 {
3666 }
3669 /* Ensure current function's preferred stack boundary is at least
3670 what we need. */
3674 /* If this kind of value comes back in memory,
3675 decide where in memory it should come back. */
3677 {
3680 {
3681 #ifdef PCC_STATIC_STRUCT_RETURN
3682 rtx pointer_reg
3692 else
3694 #endif
3695 /* This call returns a big structure. */
3697 }
3698 }
3699 else
3702 /* ??? Unfinished: must pass the memory address as an argument. */
3704 /* Copy all the libcall-arguments out of the varargs data
3705 and into a vector ARGVEC.
3707 Compute how to pass each argument. We only support a very small subset
3708 of the full argument passing conventions to limit complexity here since
3709 library functions shouldn't have many args. */
3714 #ifdef INIT_CUMULATIVE_LIBCALL_ARGS
3716 #else
3718 #endif
3725 /* Now we are about to start emitting insns that can be deleted
3726 if a libcall is deleted. */
3732 /* If there's a structure value address to be passed,
3733 either pass it in the special place, or pass it as an extra argument. */
3735 {
3737 nargs++;
3739 /* Make sure it is a reasonable operand for a move or push insn. */
3749 #ifdef FUNCTION_ARG_PARTIAL_NREGS
3752 #endif
3755 #ifdef STACK_PARMS_IN_REG_PARM_AREA
3757 #else
3759 #endif
3768 count++;
3769 }
3772 {
3776 /* We cannot convert the arg value to the mode the library wants here;
3777 must do it earlier where we know the signedness of the arg. */
3782 /* On some machines, there's no way to pass a float to a library fcn.
3783 Pass it as a double instead. */
3784 #ifdef LIBGCC_NEEDS_DOUBLE
3787 #endif
3789 /* There's no need to call protect_from_queue, because
3790 either emit_move_insn or emit_push_insn will do that. */
3792 /* Make sure it is a reasonable operand for a move or push insn. */
3797 #ifdef FUNCTION_ARG_PASS_BY_REFERENCE
3799 {
3800 rtx slot;
3802 #ifdef FUNCTION_ARG_CALLEE_COPIES
3805 #endif
3806 ;
3808 /* loop.c won't look at CALL_INSN_FUNCTION_USAGE of const/pure
3809 functions, so we have to pretend this isn't such a function. */
3811 {
3815 }
3818 /* If this was a CONST function, it is now PURE since
3819 it now reads memory. */
3821 {
3824 }
3829 {
3833 }
3834 else
3835 {
3838 slot
3844 }
3848 call_fusage);
3852 slot),
3853 call_fusage);
3857 }
3858 #endif
3865 #ifdef FUNCTION_ARG_PARTIAL_NREGS
3868 #else
3870 #endif
3873 #ifdef STACK_PARMS_IN_REG_PARM_AREA
3875 #else
3877 #endif
3889 }
3891 #ifdef FINAL_REG_PARM_STACK_SPACE
3894 #endif
3895 /* If this machine requires an external definition for library
3896 functions, write one out. */
3901 + stack_pointer_delta
3903 / STACK_BYTES
3908 reg_parm_stack_space);
3910 #ifndef OUTGOING_REG_PARM_STACK_SPACE
3912 #endif
3918 {
3919 /* Since the stack pointer will never be pushed, it is possible for
3920 the evaluation of a parm to clobber something we have already
3921 written to the stack. Since most function calls on RISC machines
3922 do not use the stack, this is uncommon, but must work correctly.
3924 Therefore, we save any area of the stack that was already written
3925 and that we are using. Here we set up to do this by making a new
3926 stack usage map from the old one.
3928 Another approach might be to try to reorder the argument
3929 evaluations to avoid this conflicting stack usage. */
3933 #ifndef OUTGOING_REG_PARM_STACK_SPACE
3934 /* Since we will be writing into the entire argument area, the
3935 map must be allocated for its entire size, not just the part that
3936 is the responsibility of the caller. */
3938 #endif
3940 #ifdef ARGS_GROW_DOWNWARD
3943 #else
3945 needed);
3946 #endif
3951 initial_highest_arg_in_use);
3958 /* We must be careful to use virtual regs before they're instantiated,
3959 and real regs afterwards. Loop optimization, for example, can create
3960 new libcalls after we've instantiated the virtual regs, and if we
3961 use virtuals anyway, they won't match the rtl patterns. */
3965 else
3967 }
3968 else
3969 {
3972 }
3974 /* If we push args individually in reverse order, perform stack alignment
3975 before the first push (the last arg). */
3981 {
3984 }
3985 else
3986 {
3989 }
3991 #ifdef REG_PARM_STACK_SPACE
3993 {
3994 /* The argument list is the property of the called routine and it
3995 may clobber it. If the fixed area has been used for previous
3996 parameters, we must save and restore it. */
3999 }
4000 #endif
4002 /* Push the args that need to be pushed. */
4004 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
4005 are to be pushed. */
4007 {
4015 {
4017 {
4018 /* If this is being stored into a pre-allocated, fixed-size,
4019 stack area, save any previous data at that location. */
4021 #ifdef ARGS_GROW_DOWNWARD
4022 /* stack_slot is negative, but we want to index stack_usage_map
4023 with positive values. */
4026 #else
4029 #endif
4032 /* Don't worry about things in the fixed argument area;
4033 it has already been saved. */
4037 i++;
4040 {
4041 /* We need to make a save area. */
4042 unsigned int size
4044 enum machine_mode save_mode
4046 rtx adr
4049 rtx stack_area
4054 }
4055 }
4060 reg_parm_stack_space,
4063 /* Now mark the segment we just used. */
4068 NO_DEFER_POP;
4069 }
4070 }
4072 /* If we pushed args in forward order, perform stack alignment
4073 after pushing the last arg. */
4080 else
4085 /* Now load any reg parms into their regs. */
4087 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
4088 are to be pushed. */
4090 {
4095 /* Handle calls that pass values in multiple non-contiguous
4096 locations. The PA64 has examples of this for library calls. */
4102 NO_DEFER_POP;
4103 }
4105 /* Any regs containing parms remain in use through the call. */
4107 {
4113 }
4115 /* Pass the function the address in which to return a structure value. */
4117 {
4121 NULL_RTX)));
4124 }
4126 /* Don't allow popping to be deferred, since then
4127 cse'ing of library calls could delete a call and leave the pop. */
4128 NO_DEFER_POP;
4132 /* Stack must be properly aligned now. */
4138 /* We pass the old value of inhibit_defer_pop + 1 to emit_call_1, which
4139 will set inhibit_defer_pop to that value. */
4140 /* The return type is needed to decide how many bytes the function pops.
4141 Signedness plays no role in that, so for simplicity, we pretend it's
4142 always signed. We also assume that the list of arguments passed has
4143 no impact, so we pretend it is unknown. */
4149 struct_value_size,
4151 valreg,
4154 /* For calls to `setjmp', etc., inform flow.c it should complain
4155 if nonvolatile values are live. For functions that cannot return,
4156 inform flow that control does not fall through. */
4159 {
4160 /* The barrier note must be emitted
4161 immediately after the CALL_INSN. Some ports emit more than
4162 just a CALL_INSN above, so we must search for it here. */
4166 {
4168 /* There was no CALL_INSN? */
4171 }
4174 }
4176 /* Now restore inhibit_defer_pop to its actual original value. */
4177 OK_DEFER_POP;
4179 /* If call is cse'able, make appropriate pair of reg-notes around it.
4180 Test valreg so we don't crash; may safely ignore `const'
4181 if return type is void. Disable for PARALLEL return values, because
4182 we have no way to move such values into a pseudo register. */
4184 {
4185 rtx insns;
4188 {
4192 }
4193 else
4194 {
4196 rtx temp;
4200 {
4204 }
4208 /* Construct an "equal form" for the value which mentions all the
4209 arguments in order as well as the function name. */
4222 note);
4227 }
4228 }
4231 /* Copy the value to the right place. */
4233 {
4235 {
4240 }
4242 {
4246 }
4249 else
4251 }
4254 {
4255 #ifdef REG_PARM_STACK_SPACE
4259 #endif
4261 /* If we saved any argument areas, restore them. */
4264 {
4272 }
4276 }
4280 }
4281 \f
4282 /* Output a library call to function FUN (a SYMBOL_REF rtx)
4283 (emitting the queue unless NO_QUEUE is nonzero),
4284 for a value of mode OUTMODE,
4285 with NARGS different arguments, passed as alternating rtx values
4286 and machine_modes to convert them to.
4287 The rtx values should have been passed through protect_from_queue already.
4289 FN_TYPE should be LCT_NORMAL for `normal' calls, LCT_CONST for `const'
4290 calls, LCT_PURE for `pure' calls, LCT_CONST_MAKE_BLOCK for `const' calls
4291 which should be enclosed in REG_LIBCALL/REG_RETVAL notes,
4292 LCT_PURE_MAKE_BLOCK for `purep' calls which should be enclosed in
4293 REG_LIBCALL/REG_RETVAL notes with extra (use (memory (scratch)),
4294 or other LCT_ value for other types of library calls. */
4296 void
4299 {
4305 }
4306 \f
4307 /* Like emit_library_call except that an extra argument, VALUE,
4308 comes second and says where to store the result.
4309 (If VALUE is zero, this function chooses a convenient way
4310 to return the value.
4312 This function returns an rtx for where the value is to be found.
4313 If VALUE is nonzero, VALUE is returned. */
4315 rtx
4319 {
4320 rtx result;
4329 }
4330 \f
4331 /* Store a single argument for a function call
4332 into the register or memory area where it must be passed.
4333 *ARG describes the argument value and where to pass it.
4335 ARGBLOCK is the address of the stack-block for all the arguments,
4336 or 0 on a machine where arguments are pushed individually.
4338 MAY_BE_ALLOCA nonzero says this could be a call to `alloca'
4339 so must be careful about how the stack is used.
4341 VARIABLE_SIZE nonzero says that this was a variable-sized outgoing
4342 argument stack. This is used if ACCUMULATE_OUTGOING_ARGS to indicate
4343 that we need not worry about saving and restoring the stack.
4345 FNDECL is the declaration of the function we are calling.
4347 Return nonzero if this arg should cause sibcall failure,
4348 zero otherwise. */
4350 static int
4353 rtx argblock;
4357 {
4368 /* Push a new temporary level for any temporaries we make for
4369 this argument. */
4373 {
4374 /* If this is being stored into a pre-allocated, fixed-size, stack area,
4375 save any previous data at that location. */
4377 {
4378 #ifdef ARGS_GROW_DOWNWARD
4379 /* stack_slot is negative, but we want to index stack_usage_map
4380 with positive values. */
4383 else
4387 #else
4390 else
4394 #endif
4397 /* Don't worry about things in the fixed argument area;
4398 it has already been saved. */
4402 i++;
4405 {
4406 /* We need to make a save area. */
4413 {
4422 BLOCK_OP_CALL_PARM);
4423 }
4424 else
4425 {
4428 }
4429 }
4430 }
4431 }
4433 /* If this isn't going to be placed on both the stack and in registers,
4434 set up the register and number of words. */
4436 {
4439 else
4442 }
4445 /* Being passed entirely in a register. We shouldn't be called in
4446 this case. */
4449 /* If this arg needs special alignment, don't load the registers
4450 here. */
4454 /* If this is being passed partially in a register, we can't evaluate
4455 it directly into its stack slot. Otherwise, we can. */
4457 {
4458 /* stack_arg_under_construction is nonzero if a function argument is
4459 being evaluated directly into the outgoing argument list and
4460 expand_call must take special action to preserve the argument list
4461 if it is called recursively.
4463 For scalar function arguments stack_usage_map is sufficient to
4464 determine which stack slots must be saved and restored. Scalar
4465 arguments in general have pass_on_stack == 0.
4467 If this argument is initialized by a function which takes the
4468 address of the argument (a C++ constructor or a C function
4469 returning a BLKmode structure), then stack_usage_map is
4470 insufficient and expand_call must push the stack around the
4471 function call. Such arguments have pass_on_stack == 1.
4473 Note that it is always safe to set stack_arg_under_construction,
4474 but this generates suboptimal code if set when not needed. */
4477 stack_arg_under_construction++;
4480 (partial
4485 /* If we are promoting object (or for any other reason) the mode
4486 doesn't agree, convert the mode. */
4493 stack_arg_under_construction--;
4494 }
4496 /* Don't allow anything left on stack from computation
4497 of argument to alloca. */
4502 /* If the value is already in the stack slot, we are done. */
4503 ;
4505 {
4508 /* Argument is a scalar, not entirely passed in registers.
4509 (If part is passed in registers, arg->partial says how much
4510 and emit_push_insn will take care of putting it there.)
4512 Push it, and if its size is less than the
4513 amount of space allocated to it,
4514 also bump stack pointer by the additional space.
4515 Note that in C the default argument promotions
4516 will prevent such mismatches. */
4519 /* Compute how much space the push instruction will push.
4520 On many machines, pushing a byte will advance the stack
4521 pointer by a halfword. */
4522 #ifdef PUSH_ROUNDING
4524 #endif
4527 /* Compute how much space the argument should get:
4528 round up to a multiple of the alignment for arguments. */
4534 /* This isn't already where we want it on the stack, so put it there.
4535 This can either be done with push or copy insns. */
4541 /* Unless this is a partially-in-register argument, the argument is now
4542 in the stack. */
4545 }
4546 else
4547 {
4548 /* BLKmode, at least partly to be pushed. */
4552 rtx size_rtx;
4554 /* Pushing a nonscalar.
4555 If part is passed in registers, PARTIAL says how much
4556 and emit_push_insn will take care of putting it there. */
4558 /* Round its size up to a multiple
4559 of the allocation unit for arguments. */
4562 {
4565 }
4566 else
4567 {
4568 /* PUSH_ROUNDING has no effect on us, because
4569 emit_push_insn for BLKmode is careful to avoid it. */
4575 }
4577 /* Some types will require stricter alignment, which will be
4578 provided for elsewhere in argument layout. */
4581 /* When an argument is padded down, the block is aligned to
4582 PARM_BOUNDARY, but the actual argument isn't. */
4584 {
4588 {
4591 }
4592 }
4595 {
4596 /* emit_push_insn might not work properly if arg->value and
4597 argblock + arg->locate.offset areas overlap. */
4604 current_function_internal_arg_pointer
4606 {
4610 /* expand_call should ensure this */
4615 {
4618 }
4620 {
4623 }
4624 }
4625 }
4632 /* Unless this is a partially-in-register argument, the argument is now
4633 in the stack.
4635 ??? Unlike the case above, in which we want the actual
4636 address of the data, so that we can load it directly into a
4637 register, here we want the address of the stack slot, so that
4638 it's properly aligned for word-by-word copying or something
4639 like that. It's not clear that this is always correct. */
4642 }
4644 /* Mark all slots this store used. */
4650 /* Once we have pushed something, pops can't safely
4651 be deferred during the rest of the arguments. */
4652 NO_DEFER_POP;
4654 /* ANSI doesn't require a sequence point here,
4655 but PCC has one, so this will avoid some problems. */
4658 /* Free any temporary slots made in processing this argument. Show
4659 that we might have taken the address of something and pushed that
4660 as an operand. */
4666 }
4668 /* Nonzero if we do not know how to pass TYPE solely in registers.
4669 We cannot do so in the following cases:
4671 - if the type has variable size
4672 - if the type is marked as addressable (it is required to be constructed
4673 into the stack)
4674 - if the padding and mode of the type is such that a copy into a register
4675 would put it into the wrong part of the register.
4677 Which padding can't be supported depends on the byte endianness.
4679 A value in a register is implicitly padded at the most significant end.
4680 On a big-endian machine, that is the lower end in memory.
4681 So a value padded in memory at the upper end can't go in a register.
4682 For a little-endian machine, the reverse is true. */
4684 bool
4687 tree type;
4688 {
4692 /* If the type has variable size... */
4696 /* If the type is marked as addressable (it is required
4697 to be constructed into the stack)... */
4701 /* If the padding and mode of the type is such that a copy into
4702 a register would put it into the wrong part of the register. */
4710 }