| blob | 482d4876f98093348029623e3e8d88f1eb333aa9 |
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. */
44 #ifndef STACK_POINTER_OFFSET
45 #define STACK_POINTER_OFFSET 0
46 #endif
48 /* Like PREFERRED_STACK_BOUNDARY but in units of bytes, not bits. */
49 #define STACK_BYTES (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT)
51 /* Data structure and subroutines used within expand_call. */
53 struct arg_data
54 {
55 /* Tree node for this argument. */
56 tree tree_value;
57 /* Mode for value; TYPE_MODE unless promoted. */
59 /* Current RTL value for argument, or 0 if it isn't precomputed. */
60 rtx value;
61 /* Initially-compute RTL value for argument; only for const functions. */
62 rtx initial_value;
63 /* Register to pass this argument in, 0 if passed on stack, or an
64 PARALLEL if the arg is to be copied into multiple non-contiguous
65 registers. */
66 rtx reg;
67 /* Register to pass this argument in when generating tail call sequence.
68 This is not the same register as for normal calls on machines with
69 register windows. */
70 rtx tail_call_reg;
71 /* If REG was promoted from the actual mode of the argument expression,
72 indicates whether the promotion is sign- or zero-extended. */
74 /* Number of registers to use. 0 means put the whole arg in registers.
75 Also 0 if not passed in registers. */
77 /* Nonzero if argument must be passed on stack.
78 Note that some arguments may be passed on the stack
79 even though pass_on_stack is zero, just because FUNCTION_ARG says so.
80 pass_on_stack identifies arguments that *cannot* go in registers. */
82 /* Some fields packaged up for locate_and_pad_parm. */
84 /* Location on the stack at which parameter should be stored. The store
85 has already been done if STACK == VALUE. */
86 rtx stack;
87 /* Location on the stack of the start of this argument slot. This can
88 differ from STACK if this arg pads downward. This location is known
89 to be aligned to FUNCTION_ARG_BOUNDARY. */
90 rtx stack_slot;
91 /* Place that this stack area has been saved, if needed. */
92 rtx save_area;
93 /* If an argument's alignment does not permit direct copying into registers,
94 copy in smaller-sized pieces into pseudos. These are stored in a
95 block pointed to by this field. The next field says how many
96 word-sized pseudos we made. */
99 };
101 /* A vector of one char per byte of stack space. A byte if nonzero if
102 the corresponding stack location has been used.
103 This vector is used to prevent a function call within an argument from
104 clobbering any stack already set up. */
107 /* Size of STACK_USAGE_MAP. */
110 /* A bitmap of virtual-incoming stack space. Bit is set if the corresponding
111 stack location's tail call argument has been already stored into the stack.
112 This bitmap is used to prevent sibling call optimization if function tries
113 to use parent's incoming argument slots when they have been already
114 overwritten with tail call arguments. */
117 /* stack_arg_under_construction is nonzero when an argument may be
118 initialized with a constructor call (including a C function that
119 returns a BLKmode struct) and expand_call must take special action
120 to make sure the object being constructed does not overlap the
121 argument list for the constructor call. */
129 CUMULATIVE_ARGS *);
156 #ifdef REG_PARM_STACK_SPACE
159 #endif
160 \f
161 /* If WHICH is 1, return 1 if EXP contains a call to the built-in function
162 `alloca'.
164 If WHICH is 0, return 1 if EXP contains a call to any function.
165 Actually, we only need return 1 if evaluating EXP would require pushing
166 arguments on the stack, but that is too difficult to compute, so we just
167 assume any function call might require the stack. */
171 static int
173 {
180 }
182 /* Recursive function to do the work of above function. */
184 static int
186 {
192 /* If this code is language-specific, we don't know what it will do. */
197 {
203 && (TYPE_RETURNS_STACK_DEPRESSED
217 {
218 tree tem;
223 }
233 calls_function_save_exprs);
238 {
239 tree local;
240 tree subblock;
248 subblock;
252 }
263 }
265 /* Only expressions and blocks can contain calls. */
275 }
276 \f
277 /* Force FUNEXP into a form suitable for the address of a CALL,
278 and return that as an rtx. Also load the static chain register
279 if FNDECL is a nested function.
281 CALL_FUSAGE points to a variable holding the prospective
282 CALL_INSN_FUNCTION_USAGE information. */
284 rtx
287 {
293 /* Get possible static chain value for nested function in C. */
296 /* Make a valid memory address and copy constants thru pseudo-regs,
297 but not for a constant address if -fno-function-cse. */
299 /* If we are using registers for parameters, force the
300 function address into a register now. */
305 {
306 #ifndef NO_FUNCTION_CSE
308 #ifdef NO_RECURSIVE_FUNCTION_CSE
310 #endif
312 #endif
313 }
316 {
321 }
324 }
326 /* Generate instructions to call function FUNEXP,
327 and optionally pop the results.
328 The CALL_INSN is the first insn generated.
330 FNDECL is the declaration node of the function. This is given to the
331 macro RETURN_POPS_ARGS to determine whether this function pops its own args.
333 FUNTYPE is the data type of the function. This is given to the macro
334 RETURN_POPS_ARGS to determine whether this function pops its own args.
335 We used to allow an identifier for library functions, but that doesn't
336 work when the return type is an aggregate type and the calling convention
337 says that the pointer to this aggregate is to be popped by the callee.
339 STACK_SIZE is the number of bytes of arguments on the stack,
340 ROUNDED_STACK_SIZE is that number rounded up to
341 PREFERRED_STACK_BOUNDARY; zero if the size is variable. This is
342 both to put into the call insn and to generate explicit popping
343 code if necessary.
345 STRUCT_VALUE_SIZE is the number of bytes wanted in a structure value.
346 It is zero if this call doesn't want a structure value.
348 NEXT_ARG_REG is the rtx that results from executing
349 FUNCTION_ARG (args_so_far, VOIDmode, void_type_node, 1)
350 just after all the args have had their registers assigned.
351 This could be whatever you like, but normally it is the first
352 arg-register beyond those used for args in this call,
353 or 0 if all the arg-registers are used in this call.
354 It is passed on to `gen_call' so you can put this info in the call insn.
356 VALREG is a hard register in which a value is returned,
357 or 0 if the call does not return a value.
359 OLD_INHIBIT_DEFER_POP is the value that `inhibit_defer_pop' had before
360 the args to this call were processed.
361 We restore `inhibit_defer_pop' to that value.
363 CALL_FUSAGE is either empty or an EXPR_LIST of USE expressions that
364 denote registers used by the called function. */
366 static void
368 HOST_WIDE_INT stack_size ATTRIBUTE_UNUSED,
369 HOST_WIDE_INT rounded_stack_size,
370 HOST_WIDE_INT struct_value_size ATTRIBUTE_UNUSED,
374 {
376 rtx call_insn;
379 #if defined (HAVE_call) && defined (HAVE_call_value)
380 rtx struct_value_size_rtx;
382 #endif
384 #ifdef CALL_POPS_ARGS
386 #endif
388 /* Ensure address is valid. SYMBOL_REF is already valid, so no need,
389 and we don't want to load it into a register as an optimization,
390 because prepare_call_address already did it if it should be done. */
394 #if defined (HAVE_sibcall_pop) && defined (HAVE_sibcall_value_pop)
398 {
400 rtx pat;
402 /* If this subroutine pops its own args, record that in the call insn
403 if possible, for the sake of frame pointer elimination. */
409 n_pop);
410 else
416 }
417 else
418 #endif
420 #if defined (HAVE_call_pop) && defined (HAVE_call_value_pop)
421 /* If the target has "call" or "call_value" insns, then prefer them
422 if no arguments are actually popped. If the target does not have
423 "call" or "call_value" insns, then we must use the popping versions
424 even if the call has no arguments to pop. */
425 #if defined (HAVE_call) && defined (HAVE_call_value)
428 #else
430 #endif
431 {
433 rtx pat;
435 /* If this subroutine pops its own args, record that in the call insn
436 if possible, for the sake of frame pointer elimination. */
442 else
448 }
449 else
450 #endif
452 #if defined (HAVE_sibcall) && defined (HAVE_sibcall_value)
455 {
459 rounded_stack_size_rtx,
461 else
464 struct_value_size_rtx));
465 }
466 else
467 #endif
469 #if defined (HAVE_call) && defined (HAVE_call_value)
471 {
476 NULL_RTX));
477 else
480 struct_value_size_rtx));
481 }
482 else
483 #endif
486 /* Find the call we just emitted. */
489 /* Mark memory as used for "pure" function call. */
491 call_fusage
492 = gen_rtx_EXPR_LIST
496 call_fusage);
498 /* Put the register usage information there. */
501 /* If this is a const call, then set the insn's unchanging bit. */
505 /* If this call can't throw, attach a REG_EH_REGION reg note to that
506 effect. */
510 else
521 {
525 }
529 /* Restore this now, so that we do defer pops for this call's args
530 if the context of the call as a whole permits. */
533 /* Don't bother cleaning up after a noreturn function. */
538 {
547 }
550 {
551 /* If returning from the subroutine does not automatically pop the args,
552 we need an instruction to pop them sooner or later.
553 Perhaps do it now; perhaps just record how much space to pop later.
555 If returning from the subroutine does pop the args, indicate that the
556 stack pointer will be changed. */
559 {
561 /* Just pretend we did the pop. */
566 else
568 }
569 }
570 /* When we accumulate outgoing args, we must avoid any stack manipulations.
571 Restore the stack pointer to its original value now. Usually
572 ACCUMULATE_OUTGOING_ARGS targets don't get here, but there are exceptions.
573 On i386 ACCUMULATE_OUTGOING_ARGS can be enabled on demand, and
574 popping variants of functions exist as well.
576 ??? We may optimize similar to defer_pop above, but it is
577 probably not worthwhile.
579 ??? It will be worthwhile to enable combine_stack_adjustments even for
580 such machines. */
583 }
585 /* Determine if the function identified by NAME and FNDECL is one with
586 special properties we wish to know about.
588 For example, if the function might return more than one time (setjmp), then
589 set RETURNS_TWICE to a nonzero value.
591 Similarly set LONGJMP for if the function is in the longjmp family.
593 Set MAY_BE_ALLOCA for any memory allocation function that might allocate
594 space from the stack such as alloca. */
596 static int
598 {
602 /* Exclude functions not at the file scope, or not `extern',
603 since they are not the magic functions we would otherwise
604 think they are.
605 FIXME: this should be handled with attributes, not with this
606 hacky imitation of DECL_ASSEMBLER_NAME. It's (also) wrong
607 because you can declare fork() inside a function if you
608 wish. */
612 {
616 /* We assume that alloca will always be called by name. It
617 makes no sense to pass it as a pointer-to-function to
618 anything that does not understand its behavior. */
627 /* Disregard prefix _, __ or __x. */
629 {
634 else
636 }
639 {
652 }
665 /* Linux specific: __clone. check NAME to insist on the
666 leading underscores, to avoid polluting the ISO / POSIX
667 namespace. */
676 }
678 }
680 /* Return nonzero when tree represent call to longjmp. */
682 int
684 {
686 }
688 /* Return true when exp contains alloca call. */
689 bool
691 {
700 }
702 /* Detect flags (function attributes) from the function decl or type node. */
704 int
706 {
711 {
716 {
721 }
723 /* The function exp may have the `malloc' attribute. */
727 /* The function exp may have the `pure' attribute. */
736 }
744 /* Mark if the function returns with the stack pointer depressed. We
745 cannot consider it pure or constant in that case. */
747 {
750 }
753 }
755 /* Precompute all register parameters as described by ARGS, storing values
756 into fields within the ARGS array.
758 NUM_ACTUALS indicates the total number elements in the ARGS array.
760 Set REG_PARM_SEEN if we encounter a register parameter. */
762 static void
764 {
771 {
775 {
782 /* ANSI doesn't require a sequence point here,
783 but PCC has one, so this will avoid some problems. */
785 }
787 /* If the value is a non-legitimate constant, force it into a
788 pseudo now. TLS symbols sometimes need a call to resolve. */
793 /* If we are to promote the function arg to a wider mode,
794 do it now. */
802 /* If the value is expensive, and we are inside an appropriately
803 short loop, put the value into a pseudo and then put the pseudo
804 into the hard reg.
806 For small register classes, also do this if this call uses
807 register parameters. This is to avoid reload conflicts while
808 loading the parameters registers. */
818 }
819 }
821 #ifdef REG_PARM_STACK_SPACE
823 /* The argument list is the property of the called routine and it
824 may clobber it. If the fixed area has been used for previous
825 parameters, we must save and restore it. */
827 static rtx
828 save_fixed_argument_area (int reg_parm_stack_space, rtx argblock, int *low_to_save, int *high_to_save)
829 {
833 /* Compute the boundary of the area that needs to be saved, if any. */
835 #ifdef ARGS_GROW_DOWNWARD
837 #endif
843 {
847 rtx stack_area;
848 rtx save_area;
851 ;
859 /* If we don't have the required alignment, must do this
860 in BLKmode. */
865 #ifdef ARGS_GROW_DOWNWARD
867 #else
869 #endif
873 delta)));
877 {
881 }
882 else
883 {
886 }
889 }
892 }
894 static void
896 {
899 rtx stack_area;
901 #ifdef ARGS_GROW_DOWNWARD
903 #else
905 #endif
913 else
916 BLOCK_OP_CALL_PARM);
917 }
920 /* If any elements in ARGS refer to parameters that are to be passed in
921 registers, but not in memory, and whose alignment does not permit a
922 direct copy into registers. Copy the values into a group of pseudos
923 which we will later copy into the appropriate hard registers.
925 Pseudos for each unaligned argument will be stored into the array
926 args[argnum].aligned_regs. The caller is responsible for deallocating
927 the aligned_regs array if it is nonzero. */
929 static void
931 {
939 {
947 /* Structures smaller than a word are normally aligned to the
948 least significant byte. On a BYTES_BIG_ENDIAN machine,
949 this means we must skip the empty high order bytes when
950 calculating the bit offset. */
952 #ifdef BLOCK_REG_PADDING
956 #else
957 && BYTES_BIG_ENDIAN
958 #endif
959 )
963 {
972 /* There is no need to restrict this code to loading items
973 in TYPE_ALIGN sized hunks. The bitfield instructions can
974 load up entire word sized registers efficiently.
976 ??? This may not be needed anymore.
977 We use to emit a clobber here but that doesn't let later
978 passes optimize the instructions we emit. By storing 0 into
979 the register later passes know the first AND to zero out the
980 bitfield being set in the register is unnecessary. The store
981 of 0 will be deleted as will at least the first AND. */
988 }
989 }
990 }
992 /* Fill in ARGS_SIZE and ARGS array based on the parameters found in
993 ACTPARMS.
995 NUM_ACTUALS is the total number of parameters.
997 N_NAMED_ARGS is the total number of named arguments.
999 FNDECL is the tree code for the target of this call (if known)
1001 ARGS_SO_FAR holds state needed by the target to know where to place
1002 the next argument.
1004 REG_PARM_STACK_SPACE is the number of bytes of stack space reserved
1005 for arguments which are passed in registers.
1007 OLD_STACK_LEVEL is a pointer to an rtx which olds the old stack level
1008 and may be modified by this routine.
1010 OLD_PENDING_ADJ, MUST_PREALLOCATE and FLAGS are pointers to integer
1011 flags which may may be modified by this routine. */
1013 static void
1023 {
1024 /* 1 if scanning parms front to back, -1 if scanning back to front. */
1027 /* Count arg position in order args appear. */
1031 tree p;
1036 /* In this loop, we consider args in the order they are written.
1037 We fill up ARGS from the front or from the back if necessary
1038 so that in any case the first arg to be pushed ends up at the front. */
1041 {
1043 /* In this case, must reverse order of args
1044 so that we compute and push the last arg first. */
1045 }
1046 else
1047 {
1049 }
1051 /* I counts args in order (to be) pushed; ARGPOS counts in order written. */
1053 {
1060 /* Replace erroneous argument with constant zero. */
1064 /* If TYPE is a transparent union, pass things the way we would
1065 pass the first field of the union. We have already verified that
1066 the modes are the same. */
1070 /* Decide where to pass this arg.
1072 args[i].reg is nonzero if all or part is passed in registers.
1074 args[i].partial is nonzero if part but not all is passed in registers,
1075 and the exact value says how many words are passed in registers.
1077 args[i].pass_on_stack is nonzero if the argument must at least be
1078 computed on the stack. It may then be loaded back into registers
1079 if args[i].reg is nonzero.
1081 These decisions are driven by the FUNCTION_... macros and must agree
1082 with those made by function.c. */
1084 /* See if this argument should be passed by invisible reference. */
1087 #ifdef FUNCTION_ARG_PASS_BY_REFERENCE
1090 #endif
1091 )
1092 {
1093 /* If we're compiling a thunk, pass through invisible
1094 references instead of making a copy. */
1096 #ifdef FUNCTION_ARG_CALLEE_COPIES
1099 /* If it's in a register, we must make a copy of it too. */
1100 /* ??? Is this a sufficient test? Is there a better one? */
1104 #endif
1105 )
1106 {
1107 /* C++ uses a TARGET_EXPR to indicate that we want to make a
1108 new object from the argument. If we are passing by
1109 invisible reference, the callee will do that for us, so we
1110 can strip off the TARGET_EXPR. This is not always safe,
1111 but it is safe in the only case where this is a useful
1112 optimization; namely, when the argument is a plain object.
1113 In that case, the frontend is just asking the backend to
1114 make a bitwise copy of the argument. */
1125 }
1127 {
1128 /* In the V3 C++ ABI, parameters are destroyed in the caller.
1129 We implement this by passing the address of the temporary
1130 rather than expanding it into another allocated slot. */
1135 }
1136 else
1137 {
1138 /* We make a copy of the object and pass the address to the
1139 function being called. */
1140 rtx copy;
1146 STACK_CHECK_MAX_VAR_SIZE))))
1147 {
1148 /* This is a variable-sized object. Make space on the stack
1149 for it. */
1153 {
1157 }
1160 allocate_dynamic_stack_space
1163 }
1164 else
1174 }
1175 }
1188 #ifdef FUNCTION_INCOMING_ARG
1189 /* If this is a sibling call and the machine has register windows, the
1190 register window has to be unwinded before calling the routine, so
1191 arguments have to go into the incoming registers. */
1194 #else
1196 #endif
1198 #ifdef FUNCTION_ARG_PARTIAL_NREGS
1203 #endif
1207 /* If FUNCTION_ARG returned a (parallel [(expr_list (nil) ...) ...]),
1208 it means that we are to pass this arg in the register(s) designated
1209 by the PARALLEL, but also to pass it in the stack. */
1214 /* If this is an addressable type, we must preallocate the stack
1215 since we must evaluate the object into its final location.
1217 If this is to be passed in both registers and the stack, it is simpler
1218 to preallocate. */
1223 /* If this is an addressable type, we cannot pre-evaluate it. Thus,
1224 we cannot consider this function call constant. */
1228 /* Compute the stack-size of this argument. */
1233 #ifdef STACK_PARMS_IN_REG_PARM_AREA
1235 #else
1237 #endif
1240 #ifdef BLOCK_REG_PADDING
1241 else
1242 /* The argument is passed entirely in registers. See at which
1243 end it should be padded. */
1247 #endif
1249 /* Update ARGS_SIZE, the total stack space for args so far. */
1255 /* Increment ARGS_SO_FAR, which has info about which arg-registers
1256 have been used, etc. */
1260 }
1261 }
1263 /* Update ARGS_SIZE to contain the total size for the argument block.
1264 Return the original constant component of the argument block's size.
1266 REG_PARM_STACK_SPACE holds the number of bytes of stack space reserved
1267 for arguments passed in registers. */
1269 static int
1273 {
1276 /* For accumulate outgoing args mode we don't need to align, since the frame
1277 will be already aligned. Align to STACK_BOUNDARY in order to prevent
1278 backends from generating misaligned frame sizes. */
1282 /* Compute the actual size of the argument block required. The variable
1283 and constant sizes must be combined, the size may have to be rounded,
1284 and there may be a minimum required size. */
1287 {
1293 {
1294 /* We don't handle this case yet. To handle it correctly we have
1295 to add the delta, round and subtract the delta.
1296 Currently no machine description requires this support. */
1300 }
1303 {
1304 args_size->var
1308 #ifndef OUTGOING_REG_PARM_STACK_SPACE
1309 /* The area corresponding to register parameters is not to count in
1310 the size of the block we need. So make the adjustment. */
1311 args_size->var
1314 #endif
1315 }
1316 }
1317 else
1318 {
1323 + stack_pointer_delta
1325 / preferred_stack_boundary
1330 reg_parm_stack_space);
1332 #ifdef MAYBE_REG_PARM_STACK_SPACE
1335 #endif
1337 #ifndef OUTGOING_REG_PARM_STACK_SPACE
1339 #endif
1340 }
1342 }
1344 /* Precompute parameters as needed for a function call.
1346 FLAGS is mask of ECF_* constants.
1348 NUM_ACTUALS is the number of arguments.
1350 ARGS is an array containing information for each argument; this
1351 routine fills in the INITIAL_VALUE and VALUE fields for each
1352 precomputed argument. */
1354 static void
1356 {
1359 /* If this function call is cse'able, precompute all the parameters.
1360 Note that if the parameter is constructed into a temporary, this will
1361 cause an additional copy because the parameter will be constructed
1362 into a temporary location and then copied into the outgoing arguments.
1363 If a parameter contains a call to alloca and this function uses the
1364 stack, precompute the parameter. */
1366 /* If we preallocated the stack space, and some arguments must be passed
1367 on the stack, then we must precompute any parameter which contains a
1368 function call which will store arguments on the stack.
1369 Otherwise, evaluating the parameter may clobber previous parameters
1370 which have already been stored into the stack. (we have code to avoid
1371 such case by saving the outgoing stack arguments, but it results in
1372 worse code) */
1377 {
1380 /* If this is an addressable type, we cannot pre-evaluate it. */
1387 /* ANSI doesn't require a sequence point here,
1388 but PCC has one, so this will avoid some problems. */
1396 {
1400 #ifdef PROMOTE_FOR_CALL_ONLY
1401 /* CSE will replace this only if it contains args[i].value
1402 pseudo, so convert it down to the declared mode using
1403 a SUBREG. */
1406 {
1412 }
1413 #endif
1414 }
1415 }
1416 }
1418 /* Given the current state of MUST_PREALLOCATE and information about
1419 arguments to a function call in NUM_ACTUALS, ARGS and ARGS_SIZE,
1420 compute and return the final value for MUST_PREALLOCATE. */
1422 static int
1423 finalize_must_preallocate (int must_preallocate, int num_actuals, struct arg_data *args, struct args_size *args_size)
1424 {
1425 /* See if we have or want to preallocate stack space.
1427 If we would have to push a partially-in-regs parm
1428 before other stack parms, preallocate stack space instead.
1430 If the size of some parm is not a multiple of the required stack
1431 alignment, we must preallocate.
1433 If the total size of arguments that would otherwise create a copy in
1434 a temporary (such as a CALL) is more than half the total argument list
1435 size, preallocation is faster.
1437 Another reason to preallocate is if we have a machine (like the m88k)
1438 where stack alignment is required to be maintained between every
1439 pair of insns, not just when the call is made. However, we assume here
1440 that such machines either do not have push insns (and hence preallocation
1441 would occur anyway) or the problem is taken care of with
1442 PUSH_ROUNDING. */
1445 {
1451 {
1462 copy_to_evaluate_size
1464 }
1469 }
1471 }
1473 /* If we preallocated stack space, compute the address of each argument
1474 and store it into the ARGS array.
1476 We need not ensure it is a valid memory address here; it will be
1477 validized when it is used.
1479 ARGBLOCK is an rtx for the address of the outgoing arguments. */
1481 static void
1483 {
1485 {
1493 {
1496 rtx addr;
1498 /* Skip this parm if it will not be passed on the stack. */
1504 else
1515 else
1524 /* Function incoming arguments may overlap with sibling call
1525 outgoing arguments and we cannot allow reordering of reads
1526 from function arguments with stores to outgoing arguments
1527 of sibling calls. */
1530 }
1531 }
1532 }
1534 /* Given a FNDECL and EXP, return an rtx suitable for use as a target address
1535 in a call instruction.
1537 FNDECL is the tree node for the target function. For an indirect call
1538 FNDECL will be NULL_TREE.
1540 ADDR is the operand 0 of CALL_EXPR for this call. */
1542 static rtx
1544 {
1545 rtx funexp;
1547 /* Get the function to call, in the form of RTL. */
1549 {
1550 /* If this is the first use of the function, see if we need to
1551 make an external definition for it. */
1553 {
1556 }
1558 /* Get a SYMBOL_REF rtx for the function address. */
1560 }
1561 else
1562 /* Generate an rtx (probably a pseudo-register) for the address. */
1563 {
1568 }
1570 }
1572 /* Do the register loads required for any wholly-register parms or any
1573 parms which are passed both on the stack and in a register. Their
1574 expressions were already evaluated.
1576 Mark all register-parms as living through the call, putting these USE
1577 insns in the CALL_INSN_FUNCTION_USAGE field.
1579 When IS_SIBCALL, perform the check_sibcall_overlap_argument_overlap
1580 checking, setting *SIBCALL_FAILURE if appropriate. */
1582 static void
1586 {
1589 #ifdef LOAD_ARGS_REVERSED
1591 #else
1593 #endif
1594 {
1598 {
1603 /* Set to non-negative if must move a word at a time, even if just
1604 one word (e.g, partial == 1 && mode == DFmode). Set to -1 if
1605 we just use a normal move insn. This value can be zero if the
1606 argument is a zero size structure with no fields. */
1611 {
1614 }
1615 else
1618 /* Handle calls that pass values in multiple non-contiguous
1619 locations. The Irix 6 ABI has examples of this. */
1622 {
1626 }
1628 /* If simple case, just do move. If normal partial, store_one_arg
1629 has already loaded the register for us. In all other cases,
1630 load the register(s) from memory. */
1633 {
1635 #ifdef BLOCK_REG_PADDING
1636 /* Handle case where we have a value that needs shifting
1637 up to the msb. eg. a QImode value and we're padding
1638 upward on a BYTES_BIG_ENDIAN machine. */
1642 {
1643 rtx x;
1646 /* Assigning REG here rather than a temp makes CALL_FUSAGE
1647 report the whole reg as used. Strictly speaking, the
1648 call only uses SIZE bytes at the msb end, but it doesn't
1649 seem worth generating rtl to say that. */
1655 }
1656 #endif
1657 }
1659 /* If we have pre-computed the values to put in the registers in
1660 the case of non-aligned structures, copy them in now. */
1668 {
1671 #ifdef BLOCK_REG_PADDING
1672 /* Handle a BLKmode that needs shifting. */
1675 {
1687 }
1688 else
1689 #endif
1691 }
1693 /* When a parameter is a block, and perhaps in other cases, it is
1694 possible that it did a load from an argument slot that was
1695 already clobbered. */
1700 /* Handle calls that pass values in multiple non-contiguous
1701 locations. The Irix 6 ABI has examples of this. */
1706 else
1708 }
1709 }
1710 }
1712 /* Try to integrate function. See expand_inline_function for documentation
1713 about the parameters. */
1715 static rtx
1718 {
1719 rtx temp;
1720 rtx before_call;
1725 #ifdef REG_PARM_STACK_SPACE
1726 #ifdef MAYBE_REG_PARM_STACK_SPACE
1728 #else
1730 #endif
1731 #endif
1739 structure_value_addr);
1743 /* If inlining succeeded, return. */
1745 {
1747 {
1748 /* If the outgoing argument list must be preserved, push
1749 the stack before executing the inlined function if it
1750 makes any calls. */
1756 ;
1759 {
1760 rtx first_insn
1764 /* Look for a call in the inline function code.
1765 If DECL_SAVED_INSNS (fndecl)->outgoing_args_size is
1766 nonzero then there is a call and it is not necessary
1767 to scan the insns. */
1775 {
1776 /* Reserve enough stack space so that the largest
1777 argument list of any function call in the inline
1778 function does not overlap the argument list being
1779 evaluated. This is usually an overestimate because
1780 allocate_dynamic_stack_space reserves space for an
1781 outgoing argument list in addition to the requested
1782 space, but there is no way to ask for stack space such
1783 that an argument list of a certain length can be
1784 safely constructed.
1786 Add the stack space reserved for register arguments, if
1787 any, in the inline function. What is really needed is the
1788 largest value of reg_parm_stack_space in the inline
1789 function, but that is not available. Using the current
1790 value of reg_parm_stack_space is wrong, but gives
1791 correct results on all supported machines. */
1804 }
1805 }
1806 }
1808 /* If the result is equivalent to TARGET, return TARGET to simplify
1809 checks in store_expr. They can be equivalent but not equal in the
1810 case of a function that returns BLKmode. */
1814 }
1816 /* If inlining failed, mark FNDECL as needing to be compiled
1817 separately after all. If function was declared inline,
1818 give a warning. */
1821 {
1825 }
1828 }
1830 /* We need to pop PENDING_STACK_ADJUST bytes. But, if the arguments
1831 wouldn't fill up an even multiple of PREFERRED_UNIT_STACK_BOUNDARY
1832 bytes, then we would need to push some additional bytes to pad the
1833 arguments. So, we compute an adjust to the stack pointer for an
1834 amount that will leave the stack under-aligned by UNADJUSTED_ARGS_SIZE
1835 bytes. Then, when the arguments are pushed the stack will be perfectly
1836 aligned. ARGS_SIZE->CONSTANT is set to the number of bytes that should
1837 be popped after the call. Returns the adjustment. */
1839 static int
1843 {
1844 /* The number of bytes to pop so that the stack will be
1845 under-aligned by UNADJUSTED_ARGS_SIZE bytes. */
1846 HOST_WIDE_INT adjustment;
1847 /* The alignment of the stack after the arguments are pushed, if we
1848 just pushed the arguments without adjust the stack here. */
1849 HOST_WIDE_INT unadjusted_alignment;
1851 unadjusted_alignment
1855 /* We want to get rid of as many of the PENDING_STACK_ADJUST bytes
1856 as possible -- leaving just enough left to cancel out the
1857 UNADJUSTED_ALIGNMENT. In other words, we want to ensure that the
1858 PENDING_STACK_ADJUST is non-negative, and congruent to
1859 -UNADJUSTED_ALIGNMENT modulo the PREFERRED_UNIT_STACK_BOUNDARY. */
1861 /* Begin by trying to pop all the bytes. */
1862 unadjusted_alignment
1863 = (unadjusted_alignment
1866 /* Push enough additional bytes that the stack will be aligned
1867 after the arguments are pushed. */
1869 {
1872 else
1874 }
1876 /* Now, sets ARGS_SIZE->CONSTANT so that we pop the right number of
1877 bytes after the call. The right number is the entire
1878 PENDING_STACK_ADJUST less our ADJUSTMENT plus the amount required
1879 by the arguments in the first place. */
1880 args_size->constant
1884 }
1886 /* Scan X expression if it does not dereference any argument slots
1887 we already clobbered by tail call arguments (as noted in stored_args_map
1888 bitmap).
1889 Return nonzero if X expression dereferences such argument slots,
1890 zero otherwise. */
1892 static int
1894 {
1895 RTX_CODE code;
1906 {
1911 current_function_internal_arg_pointer
1914 else
1917 #ifdef ARGS_GROW_DOWNWARD
1919 #endif
1927 }
1929 /* Scan all subexpressions. */
1932 {
1934 {
1937 }
1939 {
1943 }
1944 }
1946 }
1948 /* Scan sequence after INSN if it does not dereference any argument slots
1949 we already clobbered by tail call arguments (as noted in stored_args_map
1950 bitmap). If MARK_STORED_ARGS_MAP, add stack slots for ARG to
1951 stored_args_map bitmap afterwards (when ARG is a register MARK_STORED_ARGS_MAP
1952 should be 0). Return nonzero if sequence after INSN dereferences such argument
1953 slots, zero otherwise. */
1955 static int
1957 {
1962 else
1971 {
1972 #ifdef ARGS_GROW_DOWNWARD
1974 #else
1976 #endif
1980 }
1982 }
1984 static tree
1986 {
1988 {
1997 {
2003 }
2008 }
2010 }
2012 /* Generate all the code for a function call
2013 and return an rtx for its value.
2014 Store the value in TARGET (specified as an rtx) if convenient.
2015 If the value is stored in TARGET then TARGET is returned.
2016 If IGNORE is nonzero, then we ignore the value of the function call. */
2018 rtx
2020 {
2021 /* Nonzero if we are currently expanding a call. */
2024 /* List of actual parameters. */
2026 /* RTX for the function to be called. */
2027 rtx funexp;
2028 /* Sequence of insns to perform a tail recursive "call". */
2030 /* Sequence of insns to perform a normal "call". */
2032 /* Sequence of insns to perform a tail recursive "call". */
2034 /* Data type of the function. */
2035 tree funtype;
2036 tree type_arg_types;
2037 /* Declaration of the function being called,
2038 or 0 if the function is computed (not known by name). */
2040 rtx insn;
2045 /* Register in which non-BLKmode value will be returned,
2046 or 0 if no value or if value is BLKmode. */
2047 rtx valreg;
2048 /* Address where we should return a BLKmode value;
2049 0 if value not BLKmode. */
2051 /* Nonzero if that address is being passed by treating it as
2052 an extra, implicit first parameter. Otherwise,
2053 it is passed by being copied directly into struct_value_rtx. */
2055 /* Size of aggregate value wanted, or zero if none wanted
2056 or if we are using the non-reentrant PCC calling convention
2057 or expecting the value in registers. */
2059 /* Nonzero if called function returns an aggregate in memory PCC style,
2060 by returning the address of where to find it. */
2064 /* Number of actual parameters in this call, including struct value addr. */
2066 /* Number of named args. Args after this are anonymous ones
2067 and they must all go on the stack. */
2070 /* Vector of information about each argument.
2071 Arguments are numbered in the order they will be pushed,
2072 not the order they are written. */
2075 /* Total size in bytes of all the stack-parms scanned so far. */
2078 /* Size of arguments before any adjustments (such as rounding). */
2080 /* Data on reg parms scanned so far. */
2081 CUMULATIVE_ARGS args_so_far;
2082 /* Nonzero if a reg parm has been scanned. */
2084 /* Nonzero if this is an indirect function call. */
2086 /* Nonzero if we must avoid push-insns in the args for this call.
2087 If stack space is allocated for register parameters, but not by the
2088 caller, then it is preallocated in the fixed part of the stack frame.
2089 So the entire argument block must then be preallocated (i.e., we
2090 ignore PUSH_ROUNDING in that case). */
2094 /* Size of the stack reserved for parameter registers. */
2097 /* Address of space preallocated for stack parms
2098 (on machines that lack push insns), or 0 if space not preallocated. */
2101 /* Mask of ECF_ flags. */
2103 /* Nonzero if this is a call to an inline function. */
2105 #ifdef REG_PARM_STACK_SPACE
2106 /* Define the boundary of the register parm stack space that needs to be
2107 saved, if any. */
2110 #endif
2117 /* State variables to track stack modifications. */
2123 /* Some stack pointer alterations we make are performed via
2124 allocate_dynamic_stack_space. This modifies the stack_pointer_delta,
2125 which we then also need to save/restore along the way. */
2128 rtx call_fusage;
2132 /* The alignment of the stack, in bits. */
2133 HOST_WIDE_INT preferred_stack_boundary;
2134 /* The alignment of the stack, in bytes. */
2135 HOST_WIDE_INT preferred_unit_stack_boundary;
2137 /* See if this is "nothrow" function call. */
2141 /* See if we can find a DECL-node for the actual function.
2142 As a result, decide whether this is a call to an integrable function. */
2146 {
2154 {
2155 /* In case this function later becomes inlinable,
2156 record that there was already a non-inline call to it.
2158 Use abstraction instead of setting TREE_ADDRESSABLE
2159 directly. */
2162 {
2166 }
2168 }
2171 }
2173 /* If we don't have specific function to call, see if we have a
2174 attributes set in the type. */
2175 else
2180 /* Warn if this value is an aggregate type,
2181 regardless of which calling convention we are using for it. */
2185 /* If the result of a pure or const function call is ignored (or void),
2186 and none of its arguments are volatile, we can avoid expanding the
2187 call and just evaluate the arguments for side-effects. */
2191 {
2193 tree arg;
2197 {
2200 }
2203 {
2208 }
2209 }
2211 #ifdef REG_PARM_STACK_SPACE
2212 #ifdef MAYBE_REG_PARM_STACK_SPACE
2214 #else
2216 #endif
2217 #endif
2219 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2222 #endif
2224 /* Set up a place to return a structure. */
2226 /* Cater to broken compilers. */
2228 {
2229 /* This call returns a big structure. */
2232 #ifdef PCC_STATIC_STRUCT_RETURN
2233 {
2235 /* Easier than making that case work right. */
2237 {
2238 /* In case this is a static function, note that it has been
2239 used. */
2243 }
2244 }
2246 {
2250 {
2251 /* The structure value address arg is already in actparms.
2252 Pull it out. It might be nice to just leave it there, but
2253 we need to set structure_value_addr. */
2258 }
2261 else
2262 {
2263 /* For variable-sized objects, we must be called with a target
2264 specified. If we were to allocate space on the stack here,
2265 we would have no way of knowing when to free it. */
2271 }
2272 }
2274 }
2276 /* If called function is inline, try to integrate it. */
2279 {
2282 structure_value_addr);
2285 }
2287 /* Figure out the amount to which the stack should be aligned. */
2290 {
2294 }
2296 /* Operand 0 is a pointer-to-function; get the type of the function. */
2302 /* Munge the tree to split complex arguments into their imaginary
2303 and real parts. */
2305 {
2308 }
2309 else
2312 /* See if this is a call to a function that can return more than once
2313 or a call to longjmp or malloc. */
2319 /* If struct_value_rtx is 0, it means pass the address
2320 as if it were an extra parameter. */
2322 {
2323 /* If structure_value_addr is a REG other than
2324 virtual_outgoing_args_rtx, we can use always use it. If it
2325 is not a REG, we must always copy it into a register.
2326 If it is virtual_outgoing_args_rtx, we must copy it to another
2327 register in some cases. */
2329 || (ACCUMULATE_OUTGOING_ARGS
2330 && stack_arg_under_construction
2335 actparms
2338 temp),
2339 actparms);
2341 }
2343 /* Count the arguments and set NUM_ACTUALS. */
2345 num_actuals++;
2347 /* Start updating where the next arg would go.
2349 On some machines (such as the PA) indirect calls have a difuferent
2350 calling convention than normal calls. The last argument in
2351 INIT_CUMULATIVE_ARGS tells the backend if this is an indirect call
2352 or not. */
2355 /* Compute number of named args.
2356 Normally, don't include the last named arg if anonymous args follow.
2357 We do include the last named arg if STRICT_ARGUMENT_NAMING is nonzero.
2358 (If no anonymous args follow, the result of list_length is actually
2359 one too large. This is harmless.)
2361 If PRETEND_OUTGOING_VARARGS_NAMED is set and STRICT_ARGUMENT_NAMING is
2362 zero, this machine will be able to place unnamed args that were
2363 passed in registers into the stack. So treat all args as named.
2364 This allows the insns emitting for a specific argument list to be
2365 independent of the function declaration.
2367 If PRETEND_OUTGOING_VARARGS_NAMED is not set, we do not have any
2368 reliable way to pass unnamed args in registers, so we must force
2369 them into memory. */
2374 n_named_args
2376 /* Don't include the last named arg. */
2378 /* Count the struct value address, if it is passed as a parm. */
2380 else
2381 /* If we know nothing, treat all args as named. */
2384 /* Make a vector to hold all the information about each arg. */
2388 /* Build up entries in the ARGS array, compute the size of the
2389 arguments into ARGS_SIZE, etc. */
2397 {
2398 /* If this function requires a variable-sized argument list, don't
2399 try to make a cse'able block for this call. We may be able to
2400 do this eventually, but it is too complicated to keep track of
2401 what insns go in the cse'able block and which don't. */
2405 }
2407 /* Now make final decision about preallocating stack space. */
2412 /* If the structure value address will reference the stack pointer, we
2413 must stabilize it. We don't need to do this if we know that we are
2414 not going to adjust the stack pointer in processing this call. */
2419 structure_value_addr))
2424 /* Tail calls can make things harder to debug, and we're traditionally
2425 pushed these optimizations into -O2. Don't try if we're already
2426 expanding a call, as that means we're an argument. Don't try if
2427 there's cleanups, as we know there's code to follow the call.
2429 If rtx_equal_function_value_matters is false, that means we've
2430 finished with regular parsing. Which means that some of the
2431 machinery we use to generate tail-calls is no longer in place.
2432 This is most often true of sjlj-exceptions, which we couldn't
2433 tail-call to anyway. */
2436 || !flag_optimize_sibling_calls
2437 || !rtx_equal_function_value_matters
2442 /* Tail recursion fails, when we are not dealing with recursive calls. */
2448 /* Rest of purposes for tail call optimizations to fail. */
2450 #ifdef HAVE_sibcall_epilogue
2451 !HAVE_sibcall_epilogue
2452 #else
2453 1
2454 #endif
2455 || !try_tail_call
2456 /* Doing sibling call optimization needs some work, since
2457 structure_value_addr can be allocated on the stack.
2458 It does not seem worth the effort since few optimizable
2459 sibling calls will return a structure. */
2461 /* Check whether the target is able to optimize the call
2462 into a sibcall. */
2464 /* Functions that do not return exactly once may not be sibcall
2465 optimized. */
2468 /* If the called function is nested in the current one, it might access
2469 some of the caller's arguments, but could clobber them beforehand if
2470 the argument areas are shared. */
2472 /* If this function requires more stack slots than the current
2473 function, we cannot change it into a sibling call. */
2475 /* If the callee pops its own arguments, then it must pop exactly
2476 the same number of arguments as the current function. */
2480 current_function_args_size))
2485 {
2488 /* Ok, we're going to give the tail call the old college try.
2489 This means we're going to evaluate the function arguments
2490 up to three times. There are two degrees of badness we can
2491 encounter, those that can be unsaved and those that can't.
2492 (See unsafe_for_reeval commentary for details.)
2494 Generate a new argument list. Pass safe arguments through
2495 unchanged. For the easy badness wrap them in UNSAVE_EXPRs.
2496 For hard badness, evaluate them now and put their resulting
2497 rtx in a temporary VAR_DECL.
2499 initialize_argument_information has ordered the array for the
2500 order to be pushed, and we must remember this when reconstructing
2501 the original argument order. */
2504 {
2508 }
2509 else
2510 {
2514 }
2517 {
2519 /* We need to build actparms for optimize_tail_recursion. We can
2520 safely trash away TREE_PURPOSE, since it is unused by this
2521 function. */
2524 }
2525 /* Do the same for the function address if it is an expression. */
2528 /* Expanding one of those dangerous arguments could have added
2529 cleanups, but otherwise give it a whirl. */
2532 }
2534 /* Generate a tail recursion sequence when calling ourselves. */
2537 {
2538 /* We want to emit any pending stack adjustments before the tail
2539 recursion "call". That way we know any adjustment after the tail
2540 recursion call can be ignored if we indeed use the tail recursion
2541 call expansion. */
2545 /* Emit any queued insns now; otherwise they would end up in
2546 only one of the alternates. */
2549 /* Use a new sequence to hold any RTL we generate. We do not even
2550 know if we will use this RTL yet. The final decision can not be
2551 made until after RTL generation for the entire function is
2552 complete. */
2554 /* If expanding any of the arguments creates cleanups, we can't
2555 do a tailcall. So, we'll need to pop the pending cleanups
2556 list. If, however, all goes well, and there are no cleanups
2557 then the call to expand_start_target_temps will have no
2558 effect. */
2561 {
2564 else
2566 }
2570 /* Restore the original pending stack adjustment for the sibling and
2571 normal call cases below. */
2574 }
2577 {
2578 /* A fork duplicates the profile information, and an exec discards
2579 it. We can't rely on fork/exec to be paired. So write out the
2580 profile information we have gathered so far, and clear it. */
2581 /* ??? When Linux's __clone is called with CLONE_VM set, profiling
2582 is subject to race conditions, just as with multithreaded
2583 programs. */
2586 }
2588 /* Ensure current function's preferred stack boundary is at least
2589 what we need. We don't have to increase alignment for recursive
2590 functions. */
2599 function_call_count++;
2601 /* We want to make two insn chains; one for a sibling call, the other
2602 for a normal call. We will select one of the two chains after
2603 initial RTL generation is complete. */
2605 {
2607 /* We want to emit any pending stack adjustments before the tail
2608 recursion "call". That way we know any adjustment after the tail
2609 recursion call can be ignored if we indeed use the tail recursion
2610 call expansion. */
2613 rtx insns;
2617 {
2618 /* Emit any queued insns now; otherwise they would end up in
2619 only one of the alternates. */
2622 /* State variables we need to save and restore between
2623 iterations. */
2626 }
2629 else
2632 /* Other state variables that we must reinitialize each time
2633 through the loop (that are not initialized by the loop itself). */
2637 /* Start a new sequence for the normal call case.
2639 From this point on, if the sibling call fails, we want to set
2640 sibcall_failure instead of continuing the loop. */
2644 {
2645 /* We know at this point that there are not currently any
2646 pending cleanups. If, however, in the process of evaluating
2647 the arguments we were to create some, we'll need to be
2648 able to get rid of them. */
2650 }
2652 /* Don't let pending stack adjusts add up to too much.
2653 Also, do all pending adjustments now if there is any chance
2654 this might be a call to alloca or if we are expanding a sibling
2655 call sequence or if we are calling a function that is to return
2656 with stack pointer depressed. */
2663 /* When calling a const function, we must pop the stack args right away,
2664 so that the pop is deleted or moved with the call. */
2666 NO_DEFER_POP;
2668 #ifdef FINAL_REG_PARM_STACK_SPACE
2671 #endif
2672 /* Precompute any arguments as needed. */
2676 /* Now we are about to start emitting insns that can be deleted
2677 if a libcall is deleted. */
2682 /* Compute the actual size of the argument block required. The variable
2683 and constant sizes must be combined, the size may have to be rounded,
2684 and there may be a minimum required size. When generating a sibcall
2685 pattern, do not round up, since we'll be re-using whatever space our
2686 caller provided. */
2687 unadjusted_args_size
2695 /* The argument block when performing a sibling call is the
2696 incoming argument block. */
2698 {
2700 argblock
2701 #ifdef STACK_GROWS_DOWNWARD
2703 #else
2705 #endif
2708 }
2710 /* If we have no actual push instructions, or shouldn't use them,
2711 make space for all args right now. */
2713 {
2715 {
2720 /* stack_arg_under_construction says whether a stack arg is
2721 being constructed at the old stack level. Pushing the stack
2722 gets a clean outgoing argument block. */
2725 }
2727 }
2728 else
2729 {
2730 /* Note that we must go through the motions of allocating an argument
2731 block even if the size is zero because we may be storing args
2732 in the area reserved for register arguments, which may be part of
2733 the stack frame. */
2737 /* Store the maximum argument space used. It will be pushed by
2738 the prologue (if ACCUMULATE_OUTGOING_ARGS, or stack overflow
2739 checking). */
2745 {
2747 {
2748 /* Since the stack pointer will never be pushed, it is
2749 possible for the evaluation of a parm to clobber
2750 something we have already written to the stack.
2751 Since most function calls on RISC machines do not use
2752 the stack, this is uncommon, but must work correctly.
2754 Therefore, we save any area of the stack that was already
2755 written and that we are using. Here we set up to do this
2756 by making a new stack usage map from the old one. The
2757 actual save will be done by store_one_arg.
2759 Another approach might be to try to reorder the argument
2760 evaluations to avoid this conflicting stack usage. */
2762 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2763 /* Since we will be writing into the entire argument area,
2764 the map must be allocated for its entire size, not just
2765 the part that is the responsibility of the caller. */
2767 #endif
2769 #ifdef ARGS_GROW_DOWNWARD
2772 #else
2774 needed);
2775 #endif
2780 initial_highest_arg_in_use);
2784 (highest_outgoing_arg_in_use
2788 /* The address of the outgoing argument list must not be
2789 copied to a register here, because argblock would be left
2790 pointing to the wrong place after the call to
2791 allocate_dynamic_stack_space below. */
2794 }
2795 else
2796 {
2798 {
2799 /* Try to reuse some or all of the pending_stack_adjust
2800 to get this space. */
2801 needed
2802 = (combine_pending_stack_adjustment_and_call
2805 preferred_unit_stack_boundary));
2807 /* combine_pending_stack_adjustment_and_call computes
2808 an adjustment before the arguments are allocated.
2809 Account for them and see whether or not the stack
2810 needs to go up or down. */
2814 {
2815 /* We're releasing stack space. */
2816 /* ??? We can avoid any adjustment at all if we're
2817 already aligned. FIXME. */
2821 }
2822 else
2823 /* We need to allocate space. We'll do that in
2824 push_block below. */
2826 }
2828 /* Special case this because overhead of `push_block' in
2829 this case is non-trivial. */
2832 else
2833 {
2835 #ifdef ARGS_GROW_DOWNWARD
2837 #endif
2838 }
2840 /* We only really need to call `copy_to_reg' in the case
2841 where push insns are going to be used to pass ARGBLOCK
2842 to a function call in ARGS. In that case, the stack
2843 pointer changes value from the allocation point to the
2844 call point, and hence the value of
2845 VIRTUAL_OUTGOING_ARGS_RTX changes as well. But might
2846 as well always do it. */
2848 }
2849 }
2850 }
2853 {
2854 /* The save/restore code in store_one_arg handles all
2855 cases except one: a constructor call (including a C
2856 function returning a BLKmode struct) to initialize
2857 an argument. */
2859 {
2860 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2863 #else
2865 #endif
2867 {
2869 NULL_RTX);
2873 /* stack_arg_under_construction says whether a stack
2874 arg is being constructed at the old stack level.
2875 Pushing the stack gets a clean outgoing argument
2876 block. */
2877 old_stack_arg_under_construction
2880 /* Make a new map for the new argument list. */
2884 }
2886 BITS_PER_UNIT);
2887 }
2889 /* If argument evaluation might modify the stack pointer,
2890 copy the address of the argument list to a register. */
2893 {
2896 }
2897 }
2901 /* If we push args individually in reverse order, perform stack alignment
2902 before the first push (the last arg). */
2905 {
2906 /* When the stack adjustment is pending, we get better code
2907 by combining the adjustments. */
2911 {
2912 pending_stack_adjust
2913 = (combine_pending_stack_adjustment_and_call
2916 preferred_unit_stack_boundary));
2918 }
2922 }
2923 /* Now that the stack is properly aligned, pops can't safely
2924 be deferred during the evaluation of the arguments. */
2925 NO_DEFER_POP;
2929 /* Figure out the register where the value, if any, will come back. */
2933 {
2937 else
2939 }
2941 /* Precompute all register parameters. It isn't safe to compute anything
2942 once we have started filling any specific hard regs. */
2945 #ifdef REG_PARM_STACK_SPACE
2946 /* Save the fixed argument area if it's part of the caller's frame and
2947 is clobbered by argument setup for this call. */
2951 #endif
2953 /* Now store (and compute if necessary) all non-register parms.
2954 These come before register parms, since they can require block-moves,
2955 which could clobber the registers used for register parms.
2956 Parms which have partial registers are not stored here,
2957 but we do preallocate space here if they want that. */
2961 {
2966 reg_parm_stack_space)
2971 }
2973 /* If we have a parm that is passed in registers but not in memory
2974 and whose alignment does not permit a direct copy into registers,
2975 make a group of pseudos that correspond to each register that we
2976 will later fill. */
2980 /* Now store any partially-in-registers parm.
2981 This is the last place a block-move can happen. */
2985 {
2990 reg_parm_stack_space)
2995 }
2997 /* If we pushed args in forward order, perform stack alignment
2998 after pushing the last arg. */
3003 /* If register arguments require space on the stack and stack space
3004 was not preallocated, allocate stack space here for arguments
3005 passed in registers. */
3006 #ifdef OUTGOING_REG_PARM_STACK_SPACE
3010 #endif
3012 /* Pass the function the address in which to return a
3013 structure value. */
3015 {
3016 #ifdef POINTERS_EXTEND_UNSIGNED
3018 structure_value_addr = convert_memory_address
3020 #endif
3024 NULL_RTX)));
3028 }
3036 /* Perform postincrements before actually calling the function. */
3039 /* Save a pointer to the last insn before the call, so that we can
3040 later safely search backwards to find the CALL_INSN. */
3043 /* Set up next argument register. For sibling calls on machines
3044 with register windows this should be the incoming register. */
3045 #ifdef FUNCTION_INCOMING_ARG
3049 else
3050 #endif
3054 /* All arguments and registers used for the call must be set up by
3055 now! */
3057 /* Stack must be properly aligned now. */
3061 /* Generate the actual call instruction. */
3067 /* If call is cse'able, make appropriate pair of reg-notes around it.
3068 Test valreg so we don't crash; may safely ignore `const'
3069 if return type is void. Disable for PARALLEL return values, because
3070 we have no way to move such values into a pseudo register. */
3072 {
3073 rtx insns;
3074 rtx insn;
3079 /* Expansion of block moves possibly introduced a loop that may
3080 not appear inside libcall block. */
3086 {
3089 }
3090 else
3091 {
3095 /* Mark the return value as a pointer if needed. */
3100 /* Construct an "equal form" for the value which mentions all the
3101 arguments in order as well as the function name. */
3114 note);
3119 }
3120 }
3122 {
3126 /* The return value from a malloc-like function is a pointer. */
3132 /* The return value from a malloc-like function can not alias
3133 anything else. */
3138 /* Write out the sequence. */
3143 }
3145 /* For calls to `setjmp', etc., inform flow.c it should complain
3146 if nonvolatile values are live. For functions that cannot return,
3147 inform flow that control does not fall through. */
3150 {
3151 /* The barrier must be emitted
3152 immediately after the CALL_INSN. Some ports emit more
3153 than just a CALL_INSN above, so we must search for it here. */
3157 {
3159 /* There was no CALL_INSN? */
3162 }
3166 /* Stack adjustments after a noreturn call are dead code. */
3169 }
3174 /* If value type not void, return an rtx for the value. */
3176 /* If there are cleanups to be called, don't use a hard reg as target.
3177 We need to double check this and see if it matters anymore. */
3179 {
3184 }
3190 {
3192 {
3193 target
3196 structure_value_addr));
3198 }
3199 }
3201 {
3202 /* This is the special C++ case where we need to
3203 know what the true target was. We take care to
3204 never use this value more than once in one expression. */
3208 }
3209 /* Handle calls that return values in multiple non-contiguous locations.
3210 The Irix 6 ABI has examples of this. */
3212 {
3214 {
3215 /* This will only be assigned once, so it can be readonly. */
3222 }
3228 /* We can not support sibling calls for this case. */
3230 }
3234 {
3235 /* TARGET and VALREG cannot be equal at this point because the
3236 latter would not have REG_FUNCTION_VALUE_P true, while the
3237 former would if it were referring to the same register.
3239 If they refer to the same register, this move will be a no-op,
3240 except when function inlining is being done. */
3243 /* If we are setting a MEM, this code must be executed. Since it is
3244 emitted after the call insn, sibcall optimization cannot be
3245 performed in that case. */
3248 }
3250 {
3253 /* We can not support sibling calls for this case. */
3255 }
3256 else
3260 {
3261 /* If we promoted this return value, make the proper SUBREG. TARGET
3262 might be const0_rtx here, so be careful. */
3266 {
3271 /* If we don't promote as expected, something is wrong. */
3279 {
3286 }
3290 }
3291 }
3293 /* If size of args is variable or this was a constructor call for a stack
3294 argument, restore saved stack-pointer value. */
3297 {
3305 }
3307 {
3308 #ifdef REG_PARM_STACK_SPACE
3312 #endif
3314 /* If we saved any argument areas, restore them. */
3317 {
3319 rtx stack_area
3326 else
3329 BLOCK_OP_CALL_PARM);
3330 }
3334 }
3336 /* If this was alloca, record the new stack level for nonlocal gotos.
3337 Check for the handler slots since we might not have a save area
3338 for non-local gotos. */
3343 /* Free up storage we no longer need. */
3349 {
3350 /* Undo the fake expand_start_target_temps we did earlier. If
3351 there had been any cleanups created, we've already set
3352 sibcall_failure. */
3354 }
3356 /* If this function is returning into a memory location marked as
3357 readonly, it means it is initializing that location. We normally treat
3358 functions as not clobbering such locations, so we need to specify that
3359 this one does. We do this by adding the appropriate CLOBBER to the
3360 CALL_INSN function usage list. This cannot be done by emitting a
3361 standalone CLOBBER after the call because the latter would be ignored
3362 by at least the delay slot scheduling pass. We do this now instead of
3363 adding to call_fusage before the call to emit_call_1 because TARGET
3364 may be modified in the meantime. */
3367 add_function_usage_to
3370 NULL_RTX));
3376 {
3379 /* Restore the pending stack adjustment now that we have
3380 finished generating the sibling call sequence. */
3385 /* Prepare arg structure for next iteration. */
3387 {
3391 }
3394 }
3395 else
3396 {
3399 /* Verify that we've deallocated all the stack we used. */
3404 }
3406 /* If something prevents making this a sibling call,
3407 zero out the sequence. */
3410 }
3412 /* The function optimize_sibling_and_tail_recursive_calls doesn't
3413 handle CALL_PLACEHOLDERs inside other CALL_PLACEHOLDERs. This
3414 can happen if the arguments to this function call an inline
3415 function who's expansion contains another CALL_PLACEHOLDER.
3417 If there are any C_Ps in any of these sequences, replace them
3418 with their normal call. */
3435 /* If this was a potential tail recursion site, then emit a
3436 CALL_PLACEHOLDER with the normal and the tail recursion streams.
3437 One of them will be selected later. */
3439 {
3440 /* The tail recursion label must be kept around. We could expose
3441 its use in the CALL_PLACEHOLDER, but that creates unwanted edges
3442 and makes determining true tail recursion sites difficult.
3444 So we set LABEL_PRESERVE_P here, then clear it when we select
3445 one of the call sequences after rtl generation is complete. */
3449 tail_call_insns,
3450 tail_recursion_insns,
3451 tail_recursion_label));
3452 }
3453 else
3456 currently_expanding_call--;
3458 /* If this function returns with the stack pointer depressed, ensure
3459 this block saves and restores the stack pointer, show it was
3460 changed, and adjust for any outgoing arg space. */
3462 {
3467 }
3470 }
3472 /* Traverse an argument list in VALUES and expand all complex
3473 arguments into their components. */
3474 tree
3476 {
3477 tree p;
3482 {
3484 tree complex_type;
3491 {
3492 tree subtype;
3506 /* Skip the newly created node. */
3508 }
3509 }
3512 }
3514 /* Traverse a list of TYPES and expand all complex types into their
3515 components. */
3516 tree
3518 {
3519 tree p;
3524 {
3528 {
3531 /* Rewrite complex type with component type. */
3535 /* Add another component type for the imaginary part. */
3540 /* Skip the newly created node. */
3542 }
3543 }
3546 }
3547 \f
3548 /* Output a library call to function FUN (a SYMBOL_REF rtx).
3549 The RETVAL parameter specifies whether return value needs to be saved, other
3550 parameters are documented in the emit_library_call function below. */
3552 static rtx
3556 {
3557 /* Total size in bytes of all the stack-parms scanned so far. */
3559 /* Size of arguments before any adjustments (such as rounding). */
3562 rtx fun;
3566 CUMULATIVE_ARGS args_so_far;
3567 struct arg
3568 {
3569 rtx value;
3571 rtx reg;
3574 rtx save_area;
3575 };
3580 rtx valreg;
3586 rtx before_call;
3589 #ifdef REG_PARM_STACK_SPACE
3590 /* Define the boundary of the register parm stack space that needs to be
3591 save, if any. */
3594 #endif
3596 /* Size of the stack reserved for parameter registers. */
3602 #ifdef REG_PARM_STACK_SPACE
3603 #ifdef MAYBE_REG_PARM_STACK_SPACE
3605 #else
3607 #endif
3608 #endif
3610 /* By default, library functions can not throw. */
3614 {
3641 }
3644 /* Ensure current function's preferred stack boundary is at least
3645 what we need. */
3649 /* If this kind of value comes back in memory,
3650 decide where in memory it should come back. */
3652 {
3655 {
3656 #ifdef PCC_STATIC_STRUCT_RETURN
3657 rtx pointer_reg
3667 else
3669 #endif
3670 /* This call returns a big structure. */
3672 }
3673 }
3674 else
3677 /* ??? Unfinished: must pass the memory address as an argument. */
3679 /* Copy all the libcall-arguments out of the varargs data
3680 and into a vector ARGVEC.
3682 Compute how to pass each argument. We only support a very small subset
3683 of the full argument passing conventions to limit complexity here since
3684 library functions shouldn't have many args. */
3689 #ifdef INIT_CUMULATIVE_LIBCALL_ARGS
3691 #else
3693 #endif
3700 /* Now we are about to start emitting insns that can be deleted
3701 if a libcall is deleted. */
3707 /* If there's a structure value address to be passed,
3708 either pass it in the special place, or pass it as an extra argument. */
3710 {
3712 nargs++;
3714 /* Make sure it is a reasonable operand for a move or push insn. */
3724 #ifdef FUNCTION_ARG_PARTIAL_NREGS
3727 #endif
3730 #ifdef STACK_PARMS_IN_REG_PARM_AREA
3732 #else
3734 #endif
3743 count++;
3744 }
3747 {
3751 /* We cannot convert the arg value to the mode the library wants here;
3752 must do it earlier where we know the signedness of the arg. */
3757 /* There's no need to call protect_from_queue, because
3758 either emit_move_insn or emit_push_insn will do that. */
3760 /* Make sure it is a reasonable operand for a move or push insn. */
3765 #ifdef FUNCTION_ARG_PASS_BY_REFERENCE
3767 {
3768 rtx slot;
3770 #ifdef FUNCTION_ARG_CALLEE_COPIES
3773 #endif
3774 ;
3776 /* loop.c won't look at CALL_INSN_FUNCTION_USAGE of const/pure
3777 functions, so we have to pretend this isn't such a function. */
3779 {
3783 }
3786 /* If this was a CONST function, it is now PURE since
3787 it now reads memory. */
3789 {
3792 }
3797 {
3801 }
3802 else
3803 {
3806 slot
3812 }
3816 call_fusage);
3820 slot),
3821 call_fusage);
3825 }
3826 #endif
3833 #ifdef FUNCTION_ARG_PARTIAL_NREGS
3836 #else
3838 #endif
3841 #ifdef STACK_PARMS_IN_REG_PARM_AREA
3843 #else
3845 #endif
3857 }
3859 #ifdef FINAL_REG_PARM_STACK_SPACE
3862 #endif
3863 /* If this machine requires an external definition for library
3864 functions, write one out. */
3869 + stack_pointer_delta
3871 / STACK_BYTES
3876 reg_parm_stack_space);
3878 #ifndef OUTGOING_REG_PARM_STACK_SPACE
3880 #endif
3886 {
3887 /* Since the stack pointer will never be pushed, it is possible for
3888 the evaluation of a parm to clobber something we have already
3889 written to the stack. Since most function calls on RISC machines
3890 do not use the stack, this is uncommon, but must work correctly.
3892 Therefore, we save any area of the stack that was already written
3893 and that we are using. Here we set up to do this by making a new
3894 stack usage map from the old one.
3896 Another approach might be to try to reorder the argument
3897 evaluations to avoid this conflicting stack usage. */
3901 #ifndef OUTGOING_REG_PARM_STACK_SPACE
3902 /* Since we will be writing into the entire argument area, the
3903 map must be allocated for its entire size, not just the part that
3904 is the responsibility of the caller. */
3906 #endif
3908 #ifdef ARGS_GROW_DOWNWARD
3911 #else
3913 needed);
3914 #endif
3919 initial_highest_arg_in_use);
3926 /* We must be careful to use virtual regs before they're instantiated,
3927 and real regs afterwards. Loop optimization, for example, can create
3928 new libcalls after we've instantiated the virtual regs, and if we
3929 use virtuals anyway, they won't match the rtl patterns. */
3933 else
3935 }
3936 else
3937 {
3940 }
3942 /* If we push args individually in reverse order, perform stack alignment
3943 before the first push (the last arg). */
3949 {
3952 }
3953 else
3954 {
3957 }
3959 #ifdef REG_PARM_STACK_SPACE
3961 {
3962 /* The argument list is the property of the called routine and it
3963 may clobber it. If the fixed area has been used for previous
3964 parameters, we must save and restore it. */
3967 }
3968 #endif
3970 /* Push the args that need to be pushed. */
3972 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
3973 are to be pushed. */
3975 {
3983 {
3985 {
3986 /* If this is being stored into a pre-allocated, fixed-size,
3987 stack area, save any previous data at that location. */
3989 #ifdef ARGS_GROW_DOWNWARD
3990 /* stack_slot is negative, but we want to index stack_usage_map
3991 with positive values. */
3994 #else
3997 #endif
4000 /* Don't worry about things in the fixed argument area;
4001 it has already been saved. */
4005 i++;
4008 {
4009 /* We need to make a save area. */
4010 unsigned int size
4012 enum machine_mode save_mode
4014 rtx adr
4017 rtx stack_area
4021 {
4028 stack_area,
4030 BLOCK_OP_CALL_PARM);
4031 }
4032 else
4033 {
4037 }
4038 }
4039 }
4044 reg_parm_stack_space,
4047 /* Now mark the segment we just used. */
4052 NO_DEFER_POP;
4053 }
4054 }
4056 /* If we pushed args in forward order, perform stack alignment
4057 after pushing the last arg. */
4064 else
4069 /* Now load any reg parms into their regs. */
4071 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
4072 are to be pushed. */
4074 {
4079 /* Handle calls that pass values in multiple non-contiguous
4080 locations. The PA64 has examples of this for library calls. */
4086 NO_DEFER_POP;
4087 }
4089 /* Any regs containing parms remain in use through the call. */
4091 {
4097 }
4099 /* Pass the function the address in which to return a structure value. */
4101 {
4105 NULL_RTX)));
4108 }
4110 /* Don't allow popping to be deferred, since then
4111 cse'ing of library calls could delete a call and leave the pop. */
4112 NO_DEFER_POP;
4116 /* Stack must be properly aligned now. */
4122 /* We pass the old value of inhibit_defer_pop + 1 to emit_call_1, which
4123 will set inhibit_defer_pop to that value. */
4124 /* The return type is needed to decide how many bytes the function pops.
4125 Signedness plays no role in that, so for simplicity, we pretend it's
4126 always signed. We also assume that the list of arguments passed has
4127 no impact, so we pretend it is unknown. */
4133 struct_value_size,
4135 valreg,
4138 /* For calls to `setjmp', etc., inform flow.c it should complain
4139 if nonvolatile values are live. For functions that cannot return,
4140 inform flow that control does not fall through. */
4143 {
4144 /* The barrier note must be emitted
4145 immediately after the CALL_INSN. Some ports emit more than
4146 just a CALL_INSN above, so we must search for it here. */
4150 {
4152 /* There was no CALL_INSN? */
4155 }
4158 }
4160 /* Now restore inhibit_defer_pop to its actual original value. */
4161 OK_DEFER_POP;
4163 /* If call is cse'able, make appropriate pair of reg-notes around it.
4164 Test valreg so we don't crash; may safely ignore `const'
4165 if return type is void. Disable for PARALLEL return values, because
4166 we have no way to move such values into a pseudo register. */
4168 {
4169 rtx insns;
4172 {
4176 }
4177 else
4178 {
4180 rtx temp;
4184 {
4189 }
4193 /* Construct an "equal form" for the value which mentions all the
4194 arguments in order as well as the function name. */
4207 note);
4212 }
4213 }
4216 /* Copy the value to the right place. */
4218 {
4220 {
4225 }
4227 {
4231 }
4234 else
4236 }
4239 {
4240 #ifdef REG_PARM_STACK_SPACE
4244 #endif
4246 /* If we saved any argument areas, restore them. */
4249 {
4260 BLOCK_OP_CALL_PARM);
4261 else
4263 }
4267 }
4271 }
4272 \f
4273 /* Output a library call to function FUN (a SYMBOL_REF rtx)
4274 (emitting the queue unless NO_QUEUE is nonzero),
4275 for a value of mode OUTMODE,
4276 with NARGS different arguments, passed as alternating rtx values
4277 and machine_modes to convert them to.
4278 The rtx values should have been passed through protect_from_queue already.
4280 FN_TYPE should be LCT_NORMAL for `normal' calls, LCT_CONST for `const'
4281 calls, LCT_PURE for `pure' calls, LCT_CONST_MAKE_BLOCK for `const' calls
4282 which should be enclosed in REG_LIBCALL/REG_RETVAL notes,
4283 LCT_PURE_MAKE_BLOCK for `purep' calls which should be enclosed in
4284 REG_LIBCALL/REG_RETVAL notes with extra (use (memory (scratch)),
4285 or other LCT_ value for other types of library calls. */
4287 void
4290 {
4296 }
4297 \f
4298 /* Like emit_library_call except that an extra argument, VALUE,
4299 comes second and says where to store the result.
4300 (If VALUE is zero, this function chooses a convenient way
4301 to return the value.
4303 This function returns an rtx for where the value is to be found.
4304 If VALUE is nonzero, VALUE is returned. */
4306 rtx
4310 {
4311 rtx result;
4320 }
4321 \f
4322 /* Store a single argument for a function call
4323 into the register or memory area where it must be passed.
4324 *ARG describes the argument value and where to pass it.
4326 ARGBLOCK is the address of the stack-block for all the arguments,
4327 or 0 on a machine where arguments are pushed individually.
4329 MAY_BE_ALLOCA nonzero says this could be a call to `alloca'
4330 so must be careful about how the stack is used.
4332 VARIABLE_SIZE nonzero says that this was a variable-sized outgoing
4333 argument stack. This is used if ACCUMULATE_OUTGOING_ARGS to indicate
4334 that we need not worry about saving and restoring the stack.
4336 FNDECL is the declaration of the function we are calling.
4338 Return nonzero if this arg should cause sibcall failure,
4339 zero otherwise. */
4341 static int
4344 {
4355 /* Push a new temporary level for any temporaries we make for
4356 this argument. */
4360 {
4361 /* If this is being stored into a pre-allocated, fixed-size, stack area,
4362 save any previous data at that location. */
4364 {
4365 #ifdef ARGS_GROW_DOWNWARD
4366 /* stack_slot is negative, but we want to index stack_usage_map
4367 with positive values. */
4370 else
4374 #else
4377 else
4381 #endif
4384 /* Don't worry about things in the fixed argument area;
4385 it has already been saved. */
4389 i++;
4392 {
4393 /* We need to make a save area. */
4400 {
4409 BLOCK_OP_CALL_PARM);
4410 }
4411 else
4412 {
4415 }
4416 }
4417 }
4418 }
4420 /* If this isn't going to be placed on both the stack and in registers,
4421 set up the register and number of words. */
4423 {
4426 else
4429 }
4432 /* Being passed entirely in a register. We shouldn't be called in
4433 this case. */
4436 /* If this arg needs special alignment, don't load the registers
4437 here. */
4441 /* If this is being passed partially in a register, we can't evaluate
4442 it directly into its stack slot. Otherwise, we can. */
4444 {
4445 /* stack_arg_under_construction is nonzero if a function argument is
4446 being evaluated directly into the outgoing argument list and
4447 expand_call must take special action to preserve the argument list
4448 if it is called recursively.
4450 For scalar function arguments stack_usage_map is sufficient to
4451 determine which stack slots must be saved and restored. Scalar
4452 arguments in general have pass_on_stack == 0.
4454 If this argument is initialized by a function which takes the
4455 address of the argument (a C++ constructor or a C function
4456 returning a BLKmode structure), then stack_usage_map is
4457 insufficient and expand_call must push the stack around the
4458 function call. Such arguments have pass_on_stack == 1.
4460 Note that it is always safe to set stack_arg_under_construction,
4461 but this generates suboptimal code if set when not needed. */
4464 stack_arg_under_construction++;
4467 (partial
4472 /* If we are promoting object (or for any other reason) the mode
4473 doesn't agree, convert the mode. */
4480 stack_arg_under_construction--;
4481 }
4483 /* Don't allow anything left on stack from computation
4484 of argument to alloca. */
4489 /* If the value is already in the stack slot, we are done. */
4490 ;
4492 {
4495 /* Argument is a scalar, not entirely passed in registers.
4496 (If part is passed in registers, arg->partial says how much
4497 and emit_push_insn will take care of putting it there.)
4499 Push it, and if its size is less than the
4500 amount of space allocated to it,
4501 also bump stack pointer by the additional space.
4502 Note that in C the default argument promotions
4503 will prevent such mismatches. */
4506 /* Compute how much space the push instruction will push.
4507 On many machines, pushing a byte will advance the stack
4508 pointer by a halfword. */
4509 #ifdef PUSH_ROUNDING
4511 #endif
4514 /* Compute how much space the argument should get:
4515 round up to a multiple of the alignment for arguments. */
4521 /* This isn't already where we want it on the stack, so put it there.
4522 This can either be done with push or copy insns. */
4528 /* Unless this is a partially-in-register argument, the argument is now
4529 in the stack. */
4532 }
4533 else
4534 {
4535 /* BLKmode, at least partly to be pushed. */
4539 rtx size_rtx;
4541 /* Pushing a nonscalar.
4542 If part is passed in registers, PARTIAL says how much
4543 and emit_push_insn will take care of putting it there. */
4545 /* Round its size up to a multiple
4546 of the allocation unit for arguments. */
4549 {
4552 }
4553 else
4554 {
4555 /* PUSH_ROUNDING has no effect on us, because
4556 emit_push_insn for BLKmode is careful to avoid it. */
4562 }
4564 /* Some types will require stricter alignment, which will be
4565 provided for elsewhere in argument layout. */
4568 /* When an argument is padded down, the block is aligned to
4569 PARM_BOUNDARY, but the actual argument isn't. */
4571 {
4575 {
4578 }
4579 }
4582 {
4583 /* emit_push_insn might not work properly if arg->value and
4584 argblock + arg->locate.offset areas overlap. */
4591 current_function_internal_arg_pointer
4593 {
4597 /* expand_call should ensure this */
4602 {
4605 }
4607 {
4610 }
4611 }
4612 }
4619 /* Unless this is a partially-in-register argument, the argument is now
4620 in the stack.
4622 ??? Unlike the case above, in which we want the actual
4623 address of the data, so that we can load it directly into a
4624 register, here we want the address of the stack slot, so that
4625 it's properly aligned for word-by-word copying or something
4626 like that. It's not clear that this is always correct. */
4629 }
4631 /* Mark all slots this store used. */
4637 /* Once we have pushed something, pops can't safely
4638 be deferred during the rest of the arguments. */
4639 NO_DEFER_POP;
4641 /* ANSI doesn't require a sequence point here,
4642 but PCC has one, so this will avoid some problems. */
4645 /* Free any temporary slots made in processing this argument. Show
4646 that we might have taken the address of something and pushed that
4647 as an operand. */
4653 }
4655 /* Nonzero if we do not know how to pass TYPE solely in registers.
4656 We cannot do so in the following cases:
4658 - if the type has variable size
4659 - if the type is marked as addressable (it is required to be constructed
4660 into the stack)
4661 - if the padding and mode of the type is such that a copy into a register
4662 would put it into the wrong part of the register.
4664 Which padding can't be supported depends on the byte endianness.
4666 A value in a register is implicitly padded at the most significant end.
4667 On a big-endian machine, that is the lower end in memory.
4668 So a value padded in memory at the upper end can't go in a register.
4669 For a little-endian machine, the reverse is true. */
4671 bool
4673 {
4677 /* If the type has variable size... */
4681 /* If the type is marked as addressable (it is required
4682 to be constructed into the stack)... */
4686 /* If the padding and mode of the type is such that a copy into
4687 a register would put it into the wrong part of the register. */
4695 }