| blob | ef4926ee77093b4aa338fb499af6cbec4bea4295 |
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, references, 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. */
733 }
741 /* Mark if the function returns with the stack pointer depressed. We
742 cannot consider it pure or constant in that case. */
744 {
747 }
750 }
752 /* Precompute all register parameters as described by ARGS, storing values
753 into fields within the ARGS array.
755 NUM_ACTUALS indicates the total number elements in the ARGS array.
757 Set REG_PARM_SEEN if we encounter a register parameter. */
759 static void
761 {
768 {
772 {
779 /* ANSI doesn't require a sequence point here,
780 but PCC has one, so this will avoid some problems. */
782 }
784 /* If the value is a non-legitimate constant, force it into a
785 pseudo now. TLS symbols sometimes need a call to resolve. */
790 /* If we are to promote the function arg to a wider mode,
791 do it now. */
799 /* If the value is expensive, and we are inside an appropriately
800 short loop, put the value into a pseudo and then put the pseudo
801 into the hard reg.
803 For small register classes, also do this if this call uses
804 register parameters. This is to avoid reload conflicts while
805 loading the parameters registers. */
815 }
816 }
818 #ifdef REG_PARM_STACK_SPACE
820 /* The argument list is the property of the called routine and it
821 may clobber it. If the fixed area has been used for previous
822 parameters, we must save and restore it. */
824 static rtx
825 save_fixed_argument_area (int reg_parm_stack_space, rtx argblock, int *low_to_save, int *high_to_save)
826 {
830 /* Compute the boundary of the area that needs to be saved, if any. */
832 #ifdef ARGS_GROW_DOWNWARD
834 #endif
840 {
844 rtx stack_area;
845 rtx save_area;
848 ;
856 /* If we don't have the required alignment, must do this
857 in BLKmode. */
862 #ifdef ARGS_GROW_DOWNWARD
864 #else
866 #endif
870 delta)));
874 {
878 }
879 else
880 {
883 }
886 }
889 }
891 static void
893 {
896 rtx stack_area;
898 #ifdef ARGS_GROW_DOWNWARD
900 #else
902 #endif
910 else
913 BLOCK_OP_CALL_PARM);
914 }
917 /* If any elements in ARGS refer to parameters that are to be passed in
918 registers, but not in memory, and whose alignment does not permit a
919 direct copy into registers. Copy the values into a group of pseudos
920 which we will later copy into the appropriate hard registers.
922 Pseudos for each unaligned argument will be stored into the array
923 args[argnum].aligned_regs. The caller is responsible for deallocating
924 the aligned_regs array if it is nonzero. */
926 static void
928 {
936 {
945 /* Structures smaller than a word are normally aligned to the
946 least significant byte. On a BYTES_BIG_ENDIAN machine,
947 this means we must skip the empty high order bytes when
948 calculating the bit offset. */
950 #ifdef BLOCK_REG_PADDING
954 #else
955 && BYTES_BIG_ENDIAN
956 #endif
957 )
961 {
970 /* There is no need to restrict this code to loading items
971 in TYPE_ALIGN sized hunks. The bitfield instructions can
972 load up entire word sized registers efficiently.
974 ??? This may not be needed anymore.
975 We use to emit a clobber here but that doesn't let later
976 passes optimize the instructions we emit. By storing 0 into
977 the register later passes know the first AND to zero out the
978 bitfield being set in the register is unnecessary. The store
979 of 0 will be deleted as will at least the first AND. */
986 }
987 }
988 }
990 /* Fill in ARGS_SIZE and ARGS array based on the parameters found in
991 ACTPARMS.
993 NUM_ACTUALS is the total number of parameters.
995 N_NAMED_ARGS is the total number of named arguments.
997 FNDECL is the tree code for the target of this call (if known)
999 ARGS_SO_FAR holds state needed by the target to know where to place
1000 the next argument.
1002 REG_PARM_STACK_SPACE is the number of bytes of stack space reserved
1003 for arguments which are passed in registers.
1005 OLD_STACK_LEVEL is a pointer to an rtx which olds the old stack level
1006 and may be modified by this routine.
1008 OLD_PENDING_ADJ, MUST_PREALLOCATE and FLAGS are pointers to integer
1009 flags which may may be modified by this routine. */
1011 static void
1021 {
1022 /* 1 if scanning parms front to back, -1 if scanning back to front. */
1025 /* Count arg position in order args appear. */
1029 tree p;
1034 /* In this loop, we consider args in the order they are written.
1035 We fill up ARGS from the front or from the back if necessary
1036 so that in any case the first arg to be pushed ends up at the front. */
1039 {
1041 /* In this case, must reverse order of args
1042 so that we compute and push the last arg first. */
1043 }
1044 else
1045 {
1047 }
1049 /* I counts args in order (to be) pushed; ARGPOS counts in order written. */
1051 {
1058 /* Replace erroneous argument with constant zero. */
1062 /* If TYPE is a transparent union, pass things the way we would
1063 pass the first field of the union. We have already verified that
1064 the modes are the same. */
1068 /* Decide where to pass this arg.
1070 args[i].reg is nonzero if all or part is passed in registers.
1072 args[i].partial is nonzero if part but not all is passed in registers,
1073 and the exact value says how many words are passed in registers.
1075 args[i].pass_on_stack is nonzero if the argument must at least be
1076 computed on the stack. It may then be loaded back into registers
1077 if args[i].reg is nonzero.
1079 These decisions are driven by the FUNCTION_... macros and must agree
1080 with those made by function.c. */
1082 /* See if this argument should be passed by invisible reference. */
1085 #ifdef FUNCTION_ARG_PASS_BY_REFERENCE
1088 #endif
1089 )
1090 {
1091 /* If we're compiling a thunk, pass through invisible
1092 references instead of making a copy. */
1094 #ifdef FUNCTION_ARG_CALLEE_COPIES
1097 /* If it's in a register, we must make a copy of it too. */
1098 /* ??? Is this a sufficient test? Is there a better one? */
1102 #endif
1103 )
1104 {
1105 /* C++ uses a TARGET_EXPR to indicate that we want to make a
1106 new object from the argument. If we are passing by
1107 invisible reference, the callee will do that for us, so we
1108 can strip off the TARGET_EXPR. This is not always safe,
1109 but it is safe in the only case where this is a useful
1110 optimization; namely, when the argument is a plain object.
1111 In that case, the frontend is just asking the backend to
1112 make a bitwise copy of the argument. */
1123 }
1125 {
1126 /* In the V3 C++ ABI, parameters are destroyed in the caller.
1127 We implement this by passing the address of the temporary
1128 rather than expanding it into another allocated slot. */
1133 }
1134 else
1135 {
1136 /* We make a copy of the object and pass the address to the
1137 function being called. */
1138 rtx copy;
1144 STACK_CHECK_MAX_VAR_SIZE))))
1145 {
1146 /* This is a variable-sized object. Make space on the stack
1147 for it. */
1151 {
1155 }
1158 allocate_dynamic_stack_space
1161 }
1162 else
1172 }
1173 }
1178 #ifdef PROMOTE_FUNCTION_ARGS
1180 #endif
1187 #ifdef FUNCTION_INCOMING_ARG
1188 /* If this is a sibling call and the machine has register windows, the
1189 register window has to be unwinded before calling the routine, so
1190 arguments have to go into the incoming registers. */
1193 #else
1195 #endif
1197 #ifdef FUNCTION_ARG_PARTIAL_NREGS
1202 #endif
1206 /* If FUNCTION_ARG returned a (parallel [(expr_list (nil) ...) ...]),
1207 it means that we are to pass this arg in the register(s) designated
1208 by the PARALLEL, but also to pass it in the stack. */
1213 /* If this is an addressable type, we must preallocate the stack
1214 since we must evaluate the object into its final location.
1216 If this is to be passed in both registers and the stack, it is simpler
1217 to preallocate. */
1222 /* If this is an addressable type, we cannot pre-evaluate it. Thus,
1223 we cannot consider this function call constant. */
1227 /* Compute the stack-size of this argument. */
1232 #ifdef STACK_PARMS_IN_REG_PARM_AREA
1234 #else
1236 #endif
1240 /* Update ARGS_SIZE, the total stack space for args so far. */
1246 /* Increment ARGS_SO_FAR, which has info about which arg-registers
1247 have been used, etc. */
1251 }
1252 }
1254 /* Update ARGS_SIZE to contain the total size for the argument block.
1255 Return the original constant component of the argument block's size.
1257 REG_PARM_STACK_SPACE holds the number of bytes of stack space reserved
1258 for arguments passed in registers. */
1260 static int
1264 {
1267 /* For accumulate outgoing args mode we don't need to align, since the frame
1268 will be already aligned. Align to STACK_BOUNDARY in order to prevent
1269 backends from generating misaligned frame sizes. */
1273 /* Compute the actual size of the argument block required. The variable
1274 and constant sizes must be combined, the size may have to be rounded,
1275 and there may be a minimum required size. */
1278 {
1284 {
1285 /* We don't handle this case yet. To handle it correctly we have
1286 to add the delta, round and subtract the delta.
1287 Currently no machine description requires this support. */
1291 }
1294 {
1295 args_size->var
1299 #ifndef OUTGOING_REG_PARM_STACK_SPACE
1300 /* The area corresponding to register parameters is not to count in
1301 the size of the block we need. So make the adjustment. */
1302 args_size->var
1305 #endif
1306 }
1307 }
1308 else
1309 {
1314 + stack_pointer_delta
1316 / preferred_stack_boundary
1321 reg_parm_stack_space);
1323 #ifdef MAYBE_REG_PARM_STACK_SPACE
1326 #endif
1328 #ifndef OUTGOING_REG_PARM_STACK_SPACE
1330 #endif
1331 }
1333 }
1335 /* Precompute parameters as needed for a function call.
1337 FLAGS is mask of ECF_* constants.
1339 NUM_ACTUALS is the number of arguments.
1341 ARGS is an array containing information for each argument; this
1342 routine fills in the INITIAL_VALUE and VALUE fields for each
1343 precomputed argument. */
1345 static void
1347 {
1350 /* If this function call is cse'able, precompute all the parameters.
1351 Note that if the parameter is constructed into a temporary, this will
1352 cause an additional copy because the parameter will be constructed
1353 into a temporary location and then copied into the outgoing arguments.
1354 If a parameter contains a call to alloca and this function uses the
1355 stack, precompute the parameter. */
1357 /* If we preallocated the stack space, and some arguments must be passed
1358 on the stack, then we must precompute any parameter which contains a
1359 function call which will store arguments on the stack.
1360 Otherwise, evaluating the parameter may clobber previous parameters
1361 which have already been stored into the stack. (we have code to avoid
1362 such case by saving the outgoing stack arguments, but it results in
1363 worse code) */
1368 {
1371 /* If this is an addressable type, we cannot pre-evaluate it. */
1378 /* ANSI doesn't require a sequence point here,
1379 but PCC has one, so this will avoid some problems. */
1387 {
1391 #ifdef PROMOTE_FOR_CALL_ONLY
1392 /* CSE will replace this only if it contains args[i].value
1393 pseudo, so convert it down to the declared mode using
1394 a SUBREG. */
1397 {
1403 }
1404 #endif
1405 }
1406 }
1407 }
1409 /* Given the current state of MUST_PREALLOCATE and information about
1410 arguments to a function call in NUM_ACTUALS, ARGS and ARGS_SIZE,
1411 compute and return the final value for MUST_PREALLOCATE. */
1413 static int
1414 finalize_must_preallocate (int must_preallocate, int num_actuals, struct arg_data *args, struct args_size *args_size)
1415 {
1416 /* See if we have or want to preallocate stack space.
1418 If we would have to push a partially-in-regs parm
1419 before other stack parms, preallocate stack space instead.
1421 If the size of some parm is not a multiple of the required stack
1422 alignment, we must preallocate.
1424 If the total size of arguments that would otherwise create a copy in
1425 a temporary (such as a CALL) is more than half the total argument list
1426 size, preallocation is faster.
1428 Another reason to preallocate is if we have a machine (like the m88k)
1429 where stack alignment is required to be maintained between every
1430 pair of insns, not just when the call is made. However, we assume here
1431 that such machines either do not have push insns (and hence preallocation
1432 would occur anyway) or the problem is taken care of with
1433 PUSH_ROUNDING. */
1436 {
1442 {
1453 copy_to_evaluate_size
1455 }
1460 }
1462 }
1464 /* If we preallocated stack space, compute the address of each argument
1465 and store it into the ARGS array.
1467 We need not ensure it is a valid memory address here; it will be
1468 validized when it is used.
1470 ARGBLOCK is an rtx for the address of the outgoing arguments. */
1472 static void
1474 {
1476 {
1484 {
1487 rtx addr;
1489 /* Skip this parm if it will not be passed on the stack. */
1495 else
1506 else
1515 /* Function incoming arguments may overlap with sibling call
1516 outgoing arguments and we cannot allow reordering of reads
1517 from function arguments with stores to outgoing arguments
1518 of sibling calls. */
1521 }
1522 }
1523 }
1525 /* Given a FNDECL and EXP, return an rtx suitable for use as a target address
1526 in a call instruction.
1528 FNDECL is the tree node for the target function. For an indirect call
1529 FNDECL will be NULL_TREE.
1531 ADDR is the operand 0 of CALL_EXPR for this call. */
1533 static rtx
1535 {
1536 rtx funexp;
1538 /* Get the function to call, in the form of RTL. */
1540 {
1541 /* If this is the first use of the function, see if we need to
1542 make an external definition for it. */
1544 {
1547 }
1549 /* Get a SYMBOL_REF rtx for the function address. */
1551 }
1552 else
1553 /* Generate an rtx (probably a pseudo-register) for the address. */
1554 {
1559 }
1561 }
1563 /* Do the register loads required for any wholly-register parms or any
1564 parms which are passed both on the stack and in a register. Their
1565 expressions were already evaluated.
1567 Mark all register-parms as living through the call, putting these USE
1568 insns in the CALL_INSN_FUNCTION_USAGE field.
1570 When IS_SIBCALL, perform the check_sibcall_overlap_argument_overlap
1571 checking, setting *SIBCALL_FAILURE if appropriate. */
1573 static void
1577 {
1580 #ifdef LOAD_ARGS_REVERSED
1582 #else
1584 #endif
1585 {
1589 {
1594 /* Set to non-negative if must move a word at a time, even if just
1595 one word (e.g, partial == 1 && mode == DFmode). Set to -1 if
1596 we just use a normal move insn. This value can be zero if the
1597 argument is a zero size structure with no fields. */
1602 {
1605 }
1606 else
1609 /* Handle calls that pass values in multiple non-contiguous
1610 locations. The Irix 6 ABI has examples of this. */
1613 {
1617 }
1619 /* If simple case, just do move. If normal partial, store_one_arg
1620 has already loaded the register for us. In all other cases,
1621 load the register(s) from memory. */
1624 #ifdef BLOCK_REG_PADDING
1628 #endif
1629 )
1632 /* If we have pre-computed the values to put in the registers in
1633 the case of non-aligned structures, copy them in now. */
1641 {
1644 #ifdef BLOCK_REG_PADDING
1645 /* Handle case where we have a value that needs shifting
1646 up to the msb. eg. a QImode value and we're padding
1647 upward on a BYTES_BIG_ENDIAN machine. */
1649 {
1651 rtx x;
1657 }
1659 /* Handle a BLKmode that needs shifting. */
1662 {
1674 }
1675 else
1676 #endif
1678 }
1680 /* When a parameter is a block, and perhaps in other cases, it is
1681 possible that it did a load from an argument slot that was
1682 already clobbered. */
1687 /* Handle calls that pass values in multiple non-contiguous
1688 locations. The Irix 6 ABI has examples of this. */
1693 else
1695 }
1696 }
1697 }
1699 /* Try to integrate function. See expand_inline_function for documentation
1700 about the parameters. */
1702 static rtx
1705 {
1706 rtx temp;
1707 rtx before_call;
1712 #ifdef REG_PARM_STACK_SPACE
1713 #ifdef MAYBE_REG_PARM_STACK_SPACE
1715 #else
1717 #endif
1718 #endif
1726 structure_value_addr);
1730 /* If inlining succeeded, return. */
1732 {
1734 {
1735 /* If the outgoing argument list must be preserved, push
1736 the stack before executing the inlined function if it
1737 makes any calls. */
1743 ;
1746 {
1747 rtx first_insn
1751 /* Look for a call in the inline function code.
1752 If DECL_SAVED_INSNS (fndecl)->outgoing_args_size is
1753 nonzero then there is a call and it is not necessary
1754 to scan the insns. */
1762 {
1763 /* Reserve enough stack space so that the largest
1764 argument list of any function call in the inline
1765 function does not overlap the argument list being
1766 evaluated. This is usually an overestimate because
1767 allocate_dynamic_stack_space reserves space for an
1768 outgoing argument list in addition to the requested
1769 space, but there is no way to ask for stack space such
1770 that an argument list of a certain length can be
1771 safely constructed.
1773 Add the stack space reserved for register arguments, if
1774 any, in the inline function. What is really needed is the
1775 largest value of reg_parm_stack_space in the inline
1776 function, but that is not available. Using the current
1777 value of reg_parm_stack_space is wrong, but gives
1778 correct results on all supported machines. */
1791 }
1792 }
1793 }
1795 /* If the result is equivalent to TARGET, return TARGET to simplify
1796 checks in store_expr. They can be equivalent but not equal in the
1797 case of a function that returns BLKmode. */
1801 }
1803 /* If inlining failed, mark FNDECL as needing to be compiled
1804 separately after all. If function was declared inline,
1805 give a warning. */
1808 {
1811 }
1814 }
1816 /* We need to pop PENDING_STACK_ADJUST bytes. But, if the arguments
1817 wouldn't fill up an even multiple of PREFERRED_UNIT_STACK_BOUNDARY
1818 bytes, then we would need to push some additional bytes to pad the
1819 arguments. So, we compute an adjust to the stack pointer for an
1820 amount that will leave the stack under-aligned by UNADJUSTED_ARGS_SIZE
1821 bytes. Then, when the arguments are pushed the stack will be perfectly
1822 aligned. ARGS_SIZE->CONSTANT is set to the number of bytes that should
1823 be popped after the call. Returns the adjustment. */
1825 static int
1829 {
1830 /* The number of bytes to pop so that the stack will be
1831 under-aligned by UNADJUSTED_ARGS_SIZE bytes. */
1832 HOST_WIDE_INT adjustment;
1833 /* The alignment of the stack after the arguments are pushed, if we
1834 just pushed the arguments without adjust the stack here. */
1835 HOST_WIDE_INT unadjusted_alignment;
1837 unadjusted_alignment
1841 /* We want to get rid of as many of the PENDING_STACK_ADJUST bytes
1842 as possible -- leaving just enough left to cancel out the
1843 UNADJUSTED_ALIGNMENT. In other words, we want to ensure that the
1844 PENDING_STACK_ADJUST is non-negative, and congruent to
1845 -UNADJUSTED_ALIGNMENT modulo the PREFERRED_UNIT_STACK_BOUNDARY. */
1847 /* Begin by trying to pop all the bytes. */
1848 unadjusted_alignment
1849 = (unadjusted_alignment
1852 /* Push enough additional bytes that the stack will be aligned
1853 after the arguments are pushed. */
1855 {
1858 else
1860 }
1862 /* Now, sets ARGS_SIZE->CONSTANT so that we pop the right number of
1863 bytes after the call. The right number is the entire
1864 PENDING_STACK_ADJUST less our ADJUSTMENT plus the amount required
1865 by the arguments in the first place. */
1866 args_size->constant
1870 }
1872 /* Scan X expression if it does not dereference any argument slots
1873 we already clobbered by tail call arguments (as noted in stored_args_map
1874 bitmap).
1875 Return nonzero if X expression dereferences such argument slots,
1876 zero otherwise. */
1878 static int
1880 {
1881 RTX_CODE code;
1892 {
1897 current_function_internal_arg_pointer
1900 else
1903 #ifdef ARGS_GROW_DOWNWARD
1905 #endif
1913 }
1915 /* Scan all subexpressions. */
1918 {
1920 {
1923 }
1925 {
1929 }
1930 }
1932 }
1934 /* Scan sequence after INSN if it does not dereference any argument slots
1935 we already clobbered by tail call arguments (as noted in stored_args_map
1936 bitmap). If MARK_STORED_ARGS_MAP, add stack slots for ARG to
1937 stored_args_map bitmap afterwards (when ARG is a register MARK_STORED_ARGS_MAP
1938 should be 0). Return nonzero if sequence after INSN dereferences such argument
1939 slots, zero otherwise. */
1941 static int
1943 {
1948 else
1957 {
1958 #ifdef ARGS_GROW_DOWNWARD
1960 #else
1962 #endif
1966 }
1968 }
1970 static tree
1972 {
1974 {
1983 {
1989 }
1994 }
1996 }
1998 /* Generate all the code for a function call
1999 and return an rtx for its value.
2000 Store the value in TARGET (specified as an rtx) if convenient.
2001 If the value is stored in TARGET then TARGET is returned.
2002 If IGNORE is nonzero, then we ignore the value of the function call. */
2004 rtx
2006 {
2007 /* Nonzero if we are currently expanding a call. */
2010 /* List of actual parameters. */
2012 /* RTX for the function to be called. */
2013 rtx funexp;
2014 /* Sequence of insns to perform a tail recursive "call". */
2016 /* Sequence of insns to perform a normal "call". */
2018 /* Sequence of insns to perform a tail recursive "call". */
2020 /* Data type of the function. */
2021 tree funtype;
2022 tree type_arg_types;
2023 /* Declaration of the function being called,
2024 or 0 if the function is computed (not known by name). */
2026 rtx insn;
2031 /* Register in which non-BLKmode value will be returned,
2032 or 0 if no value or if value is BLKmode. */
2033 rtx valreg;
2034 /* Address where we should return a BLKmode value;
2035 0 if value not BLKmode. */
2037 /* Nonzero if that address is being passed by treating it as
2038 an extra, implicit first parameter. Otherwise,
2039 it is passed by being copied directly into struct_value_rtx. */
2041 /* Size of aggregate value wanted, or zero if none wanted
2042 or if we are using the non-reentrant PCC calling convention
2043 or expecting the value in registers. */
2045 /* Nonzero if called function returns an aggregate in memory PCC style,
2046 by returning the address of where to find it. */
2049 /* Number of actual parameters in this call, including struct value addr. */
2051 /* Number of named args. Args after this are anonymous ones
2052 and they must all go on the stack. */
2055 /* Vector of information about each argument.
2056 Arguments are numbered in the order they will be pushed,
2057 not the order they are written. */
2060 /* Total size in bytes of all the stack-parms scanned so far. */
2063 /* Size of arguments before any adjustments (such as rounding). */
2065 /* Data on reg parms scanned so far. */
2066 CUMULATIVE_ARGS args_so_far;
2067 /* Nonzero if a reg parm has been scanned. */
2069 /* Nonzero if this is an indirect function call. */
2071 /* Nonzero if we must avoid push-insns in the args for this call.
2072 If stack space is allocated for register parameters, but not by the
2073 caller, then it is preallocated in the fixed part of the stack frame.
2074 So the entire argument block must then be preallocated (i.e., we
2075 ignore PUSH_ROUNDING in that case). */
2079 /* Size of the stack reserved for parameter registers. */
2082 /* Address of space preallocated for stack parms
2083 (on machines that lack push insns), or 0 if space not preallocated. */
2086 /* Mask of ECF_ flags. */
2088 /* Nonzero if this is a call to an inline function. */
2090 #ifdef REG_PARM_STACK_SPACE
2091 /* Define the boundary of the register parm stack space that needs to be
2092 saved, if any. */
2095 #endif
2102 /* State variables to track stack modifications. */
2108 /* Some stack pointer alterations we make are performed via
2109 allocate_dynamic_stack_space. This modifies the stack_pointer_delta,
2110 which we then also need to save/restore along the way. */
2113 rtx call_fusage;
2117 /* The alignment of the stack, in bits. */
2118 HOST_WIDE_INT preferred_stack_boundary;
2119 /* The alignment of the stack, in bytes. */
2120 HOST_WIDE_INT preferred_unit_stack_boundary;
2122 /* See if this is "nothrow" function call. */
2126 /* See if we can find a DECL-node for the actual function.
2127 As a result, decide whether this is a call to an integrable function. */
2131 {
2139 {
2140 /* In case this function later becomes inlinable,
2141 record that there was already a non-inline call to it.
2143 Use abstraction instead of setting TREE_ADDRESSABLE
2144 directly. */
2147 {
2150 }
2152 }
2155 }
2157 /* If we don't have specific function to call, see if we have a
2158 attributes set in the type. */
2159 else
2162 /* Warn if this value is an aggregate type,
2163 regardless of which calling convention we are using for it. */
2167 /* If the result of a pure or const function call is ignored (or void),
2168 and none of its arguments are volatile, we can avoid expanding the
2169 call and just evaluate the arguments for side-effects. */
2173 {
2175 tree arg;
2179 {
2182 }
2185 {
2190 }
2191 }
2193 #ifdef REG_PARM_STACK_SPACE
2194 #ifdef MAYBE_REG_PARM_STACK_SPACE
2196 #else
2198 #endif
2199 #endif
2201 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2204 #endif
2206 /* Set up a place to return a structure. */
2208 /* Cater to broken compilers. */
2210 {
2211 /* This call returns a big structure. */
2214 #ifdef PCC_STATIC_STRUCT_RETURN
2215 {
2217 /* Easier than making that case work right. */
2219 {
2220 /* In case this is a static function, note that it has been
2221 used. */
2225 }
2226 }
2228 {
2232 {
2233 /* The structure value address arg is already in actparms.
2234 Pull it out. It might be nice to just leave it there, but
2235 we need to set structure_value_addr. */
2240 }
2243 else
2244 {
2245 /* For variable-sized objects, we must be called with a target
2246 specified. If we were to allocate space on the stack here,
2247 we would have no way of knowing when to free it. */
2253 }
2254 }
2256 }
2258 /* If called function is inline, try to integrate it. */
2261 {
2264 structure_value_addr);
2267 }
2269 /* Figure out the amount to which the stack should be aligned. */
2272 {
2276 }
2278 /* Operand 0 is a pointer-to-function; get the type of the function. */
2284 /* Munge the tree to split complex arguments into their imaginary
2285 and real parts. */
2287 {
2290 }
2291 else
2294 /* See if this is a call to a function that can return more than once
2295 or a call to longjmp or malloc. */
2301 /* If struct_value_rtx is 0, it means pass the address
2302 as if it were an extra parameter. */
2304 {
2305 /* If structure_value_addr is a REG other than
2306 virtual_outgoing_args_rtx, we can use always use it. If it
2307 is not a REG, we must always copy it into a register.
2308 If it is virtual_outgoing_args_rtx, we must copy it to another
2309 register in some cases. */
2311 || (ACCUMULATE_OUTGOING_ARGS
2312 && stack_arg_under_construction
2317 actparms
2320 temp),
2321 actparms);
2323 }
2325 /* Count the arguments and set NUM_ACTUALS. */
2327 num_actuals++;
2329 /* Compute number of named args.
2330 Normally, don't include the last named arg if anonymous args follow.
2331 We do include the last named arg if STRICT_ARGUMENT_NAMING is nonzero.
2332 (If no anonymous args follow, the result of list_length is actually
2333 one too large. This is harmless.)
2335 If PRETEND_OUTGOING_VARARGS_NAMED is set and STRICT_ARGUMENT_NAMING is
2336 zero, this machine will be able to place unnamed args that were
2337 passed in registers into the stack. So treat all args as named.
2338 This allows the insns emitting for a specific argument list to be
2339 independent of the function declaration.
2341 If PRETEND_OUTGOING_VARARGS_NAMED is not set, we do not have any
2342 reliable way to pass unnamed args in registers, so we must force
2343 them into memory. */
2348 n_named_args
2350 /* Don't include the last named arg. */
2352 /* Count the struct value address, if it is passed as a parm. */
2354 else
2355 /* If we know nothing, treat all args as named. */
2358 /* Start updating where the next arg would go.
2360 On some machines (such as the PA) indirect calls have a different
2361 calling convention than normal calls. The last argument in
2362 INIT_CUMULATIVE_ARGS tells the backend if this is an indirect call
2363 or not. */
2366 /* Make a vector to hold all the information about each arg. */
2370 /* Build up entries in the ARGS array, compute the size of the
2371 arguments into ARGS_SIZE, etc. */
2379 {
2380 /* If this function requires a variable-sized argument list, don't
2381 try to make a cse'able block for this call. We may be able to
2382 do this eventually, but it is too complicated to keep track of
2383 what insns go in the cse'able block and which don't. */
2387 }
2389 /* Now make final decision about preallocating stack space. */
2394 /* If the structure value address will reference the stack pointer, we
2395 must stabilize it. We don't need to do this if we know that we are
2396 not going to adjust the stack pointer in processing this call. */
2401 structure_value_addr))
2406 /* Tail calls can make things harder to debug, and we're traditionally
2407 pushed these optimizations into -O2. Don't try if we're already
2408 expanding a call, as that means we're an argument. Don't try if
2409 there's cleanups, as we know there's code to follow the call.
2411 If rtx_equal_function_value_matters is false, that means we've
2412 finished with regular parsing. Which means that some of the
2413 machinery we use to generate tail-calls is no longer in place.
2414 This is most often true of sjlj-exceptions, which we couldn't
2415 tail-call to anyway. */
2418 || !flag_optimize_sibling_calls
2419 || !rtx_equal_function_value_matters
2424 /* Tail recursion fails, when we are not dealing with recursive calls. */
2430 /* Rest of purposes for tail call optimizations to fail. */
2432 #ifdef HAVE_sibcall_epilogue
2433 !HAVE_sibcall_epilogue
2434 #else
2435 1
2436 #endif
2437 || !try_tail_call
2438 /* Doing sibling call optimization needs some work, since
2439 structure_value_addr can be allocated on the stack.
2440 It does not seem worth the effort since few optimizable
2441 sibling calls will return a structure. */
2443 /* Check whether the target is able to optimize the call
2444 into a sibcall. */
2446 /* Functions that do not return exactly once may not be sibcall
2447 optimized. */
2450 /* If the called function is nested in the current one, it might access
2451 some of the caller's arguments, but could clobber them beforehand if
2452 the argument areas are shared. */
2454 /* If this function requires more stack slots than the current
2455 function, we cannot change it into a sibling call. */
2457 /* If the callee pops its own arguments, then it must pop exactly
2458 the same number of arguments as the current function. */
2462 current_function_args_size))
2467 {
2470 /* Ok, we're going to give the tail call the old college try.
2471 This means we're going to evaluate the function arguments
2472 up to three times. There are two degrees of badness we can
2473 encounter, those that can be unsaved and those that can't.
2474 (See unsafe_for_reeval commentary for details.)
2476 Generate a new argument list. Pass safe arguments through
2477 unchanged. For the easy badness wrap them in UNSAVE_EXPRs.
2478 For hard badness, evaluate them now and put their resulting
2479 rtx in a temporary VAR_DECL.
2481 initialize_argument_information has ordered the array for the
2482 order to be pushed, and we must remember this when reconstructing
2483 the original argument order. */
2486 {
2490 }
2491 else
2492 {
2496 }
2499 {
2501 /* We need to build actparms for optimize_tail_recursion. We can
2502 safely trash away TREE_PURPOSE, since it is unused by this
2503 function. */
2506 }
2507 /* Do the same for the function address if it is an expression. */
2510 /* Expanding one of those dangerous arguments could have added
2511 cleanups, but otherwise give it a whirl. */
2514 }
2516 /* Generate a tail recursion sequence when calling ourselves. */
2519 {
2520 /* We want to emit any pending stack adjustments before the tail
2521 recursion "call". That way we know any adjustment after the tail
2522 recursion call can be ignored if we indeed use the tail recursion
2523 call expansion. */
2527 /* Emit any queued insns now; otherwise they would end up in
2528 only one of the alternates. */
2531 /* Use a new sequence to hold any RTL we generate. We do not even
2532 know if we will use this RTL yet. The final decision can not be
2533 made until after RTL generation for the entire function is
2534 complete. */
2536 /* If expanding any of the arguments creates cleanups, we can't
2537 do a tailcall. So, we'll need to pop the pending cleanups
2538 list. If, however, all goes well, and there are no cleanups
2539 then the call to expand_start_target_temps will have no
2540 effect. */
2543 {
2546 else
2548 }
2552 /* Restore the original pending stack adjustment for the sibling and
2553 normal call cases below. */
2556 }
2559 {
2560 /* A fork duplicates the profile information, and an exec discards
2561 it. We can't rely on fork/exec to be paired. So write out the
2562 profile information we have gathered so far, and clear it. */
2563 /* ??? When Linux's __clone is called with CLONE_VM set, profiling
2564 is subject to race conditions, just as with multithreaded
2565 programs. */
2568 }
2570 /* Ensure current function's preferred stack boundary is at least
2571 what we need. We don't have to increase alignment for recursive
2572 functions. */
2581 function_call_count++;
2583 /* We want to make two insn chains; one for a sibling call, the other
2584 for a normal call. We will select one of the two chains after
2585 initial RTL generation is complete. */
2587 {
2589 /* We want to emit any pending stack adjustments before the tail
2590 recursion "call". That way we know any adjustment after the tail
2591 recursion call can be ignored if we indeed use the tail recursion
2592 call expansion. */
2595 rtx insns;
2599 {
2600 /* Emit any queued insns now; otherwise they would end up in
2601 only one of the alternates. */
2604 /* State variables we need to save and restore between
2605 iterations. */
2608 }
2611 else
2614 /* Other state variables that we must reinitialize each time
2615 through the loop (that are not initialized by the loop itself). */
2619 /* Start a new sequence for the normal call case.
2621 From this point on, if the sibling call fails, we want to set
2622 sibcall_failure instead of continuing the loop. */
2626 {
2627 /* We know at this point that there are not currently any
2628 pending cleanups. If, however, in the process of evaluating
2629 the arguments we were to create some, we'll need to be
2630 able to get rid of them. */
2632 }
2634 /* Don't let pending stack adjusts add up to too much.
2635 Also, do all pending adjustments now if there is any chance
2636 this might be a call to alloca or if we are expanding a sibling
2637 call sequence or if we are calling a function that is to return
2638 with stack pointer depressed. */
2645 /* When calling a const function, we must pop the stack args right away,
2646 so that the pop is deleted or moved with the call. */
2648 NO_DEFER_POP;
2650 #ifdef FINAL_REG_PARM_STACK_SPACE
2653 #endif
2654 /* Precompute any arguments as needed. */
2658 /* Now we are about to start emitting insns that can be deleted
2659 if a libcall is deleted. */
2664 /* Compute the actual size of the argument block required. The variable
2665 and constant sizes must be combined, the size may have to be rounded,
2666 and there may be a minimum required size. When generating a sibcall
2667 pattern, do not round up, since we'll be re-using whatever space our
2668 caller provided. */
2669 unadjusted_args_size
2677 /* The argument block when performing a sibling call is the
2678 incoming argument block. */
2680 {
2682 argblock
2683 #ifdef STACK_GROWS_DOWNWARD
2685 #else
2687 #endif
2690 }
2692 /* If we have no actual push instructions, or shouldn't use them,
2693 make space for all args right now. */
2695 {
2697 {
2702 /* stack_arg_under_construction says whether a stack arg is
2703 being constructed at the old stack level. Pushing the stack
2704 gets a clean outgoing argument block. */
2707 }
2709 }
2710 else
2711 {
2712 /* Note that we must go through the motions of allocating an argument
2713 block even if the size is zero because we may be storing args
2714 in the area reserved for register arguments, which may be part of
2715 the stack frame. */
2719 /* Store the maximum argument space used. It will be pushed by
2720 the prologue (if ACCUMULATE_OUTGOING_ARGS, or stack overflow
2721 checking). */
2727 {
2729 {
2730 /* Since the stack pointer will never be pushed, it is
2731 possible for the evaluation of a parm to clobber
2732 something we have already written to the stack.
2733 Since most function calls on RISC machines do not use
2734 the stack, this is uncommon, but must work correctly.
2736 Therefore, we save any area of the stack that was already
2737 written and that we are using. Here we set up to do this
2738 by making a new stack usage map from the old one. The
2739 actual save will be done by store_one_arg.
2741 Another approach might be to try to reorder the argument
2742 evaluations to avoid this conflicting stack usage. */
2744 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2745 /* Since we will be writing into the entire argument area,
2746 the map must be allocated for its entire size, not just
2747 the part that is the responsibility of the caller. */
2749 #endif
2751 #ifdef ARGS_GROW_DOWNWARD
2754 #else
2756 needed);
2757 #endif
2758 stack_usage_map
2763 initial_highest_arg_in_use);
2767 (highest_outgoing_arg_in_use
2771 /* The address of the outgoing argument list must not be
2772 copied to a register here, because argblock would be left
2773 pointing to the wrong place after the call to
2774 allocate_dynamic_stack_space below. */
2777 }
2778 else
2779 {
2781 {
2782 /* Try to reuse some or all of the pending_stack_adjust
2783 to get this space. */
2784 needed
2785 = (combine_pending_stack_adjustment_and_call
2788 preferred_unit_stack_boundary));
2790 /* combine_pending_stack_adjustment_and_call computes
2791 an adjustment before the arguments are allocated.
2792 Account for them and see whether or not the stack
2793 needs to go up or down. */
2797 {
2798 /* We're releasing stack space. */
2799 /* ??? We can avoid any adjustment at all if we're
2800 already aligned. FIXME. */
2804 }
2805 else
2806 /* We need to allocate space. We'll do that in
2807 push_block below. */
2809 }
2811 /* Special case this because overhead of `push_block' in
2812 this case is non-trivial. */
2815 else
2816 {
2818 #ifdef ARGS_GROW_DOWNWARD
2820 #endif
2821 }
2823 /* We only really need to call `copy_to_reg' in the case
2824 where push insns are going to be used to pass ARGBLOCK
2825 to a function call in ARGS. In that case, the stack
2826 pointer changes value from the allocation point to the
2827 call point, and hence the value of
2828 VIRTUAL_OUTGOING_ARGS_RTX changes as well. But might
2829 as well always do it. */
2831 }
2832 }
2833 }
2836 {
2837 /* The save/restore code in store_one_arg handles all
2838 cases except one: a constructor call (including a C
2839 function returning a BLKmode struct) to initialize
2840 an argument. */
2842 {
2843 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2846 #else
2848 #endif
2850 {
2852 NULL_RTX);
2856 /* stack_arg_under_construction says whether a stack
2857 arg is being constructed at the old stack level.
2858 Pushing the stack gets a clean outgoing argument
2859 block. */
2860 old_stack_arg_under_construction
2863 /* Make a new map for the new argument list. */
2868 }
2870 BITS_PER_UNIT);
2871 }
2873 /* If argument evaluation might modify the stack pointer,
2874 copy the address of the argument list to a register. */
2877 {
2880 }
2881 }
2885 /* If we push args individually in reverse order, perform stack alignment
2886 before the first push (the last arg). */
2889 {
2890 /* When the stack adjustment is pending, we get better code
2891 by combining the adjustments. */
2895 {
2896 pending_stack_adjust
2897 = (combine_pending_stack_adjustment_and_call
2900 preferred_unit_stack_boundary));
2902 }
2906 }
2907 /* Now that the stack is properly aligned, pops can't safely
2908 be deferred during the evaluation of the arguments. */
2909 NO_DEFER_POP;
2913 /* Figure out the register where the value, if any, will come back. */
2917 {
2921 else
2923 }
2925 /* Precompute all register parameters. It isn't safe to compute anything
2926 once we have started filling any specific hard regs. */
2929 #ifdef REG_PARM_STACK_SPACE
2930 /* Save the fixed argument area if it's part of the caller's frame and
2931 is clobbered by argument setup for this call. */
2935 #endif
2937 /* Now store (and compute if necessary) all non-register parms.
2938 These come before register parms, since they can require block-moves,
2939 which could clobber the registers used for register parms.
2940 Parms which have partial registers are not stored here,
2941 but we do preallocate space here if they want that. */
2945 {
2950 reg_parm_stack_space)
2955 }
2957 /* If we have a parm that is passed in registers but not in memory
2958 and whose alignment does not permit a direct copy into registers,
2959 make a group of pseudos that correspond to each register that we
2960 will later fill. */
2964 /* Now store any partially-in-registers parm.
2965 This is the last place a block-move can happen. */
2969 {
2974 reg_parm_stack_space)
2979 }
2981 /* If we pushed args in forward order, perform stack alignment
2982 after pushing the last arg. */
2987 /* If register arguments require space on the stack and stack space
2988 was not preallocated, allocate stack space here for arguments
2989 passed in registers. */
2990 #ifdef OUTGOING_REG_PARM_STACK_SPACE
2994 #endif
2996 /* Pass the function the address in which to return a
2997 structure value. */
2999 {
3000 #ifdef POINTERS_EXTEND_UNSIGNED
3002 structure_value_addr = convert_memory_address
3004 #endif
3008 NULL_RTX)));
3012 }
3020 /* Perform postincrements before actually calling the function. */
3023 /* Save a pointer to the last insn before the call, so that we can
3024 later safely search backwards to find the CALL_INSN. */
3027 /* Set up next argument register. For sibling calls on machines
3028 with register windows this should be the incoming register. */
3029 #ifdef FUNCTION_INCOMING_ARG
3033 else
3034 #endif
3038 /* All arguments and registers used for the call must be set up by
3039 now! */
3041 /* Stack must be properly aligned now. */
3045 /* Generate the actual call instruction. */
3051 /* If call is cse'able, make appropriate pair of reg-notes around it.
3052 Test valreg so we don't crash; may safely ignore `const'
3053 if return type is void. Disable for PARALLEL return values, because
3054 we have no way to move such values into a pseudo register. */
3056 {
3057 rtx insns;
3060 {
3064 }
3065 else
3066 {
3070 /* Mark the return value as a pointer if needed. */
3075 /* Construct an "equal form" for the value which mentions all the
3076 arguments in order as well as the function name. */
3090 note);
3095 }
3096 }
3098 {
3102 /* The return value from a malloc-like function is a pointer. */
3108 /* The return value from a malloc-like function can not alias
3109 anything else. */
3114 /* Write out the sequence. */
3119 }
3121 /* For calls to `setjmp', etc., inform flow.c it should complain
3122 if nonvolatile values are live. For functions that cannot return,
3123 inform flow that control does not fall through. */
3126 {
3127 /* The barrier must be emitted
3128 immediately after the CALL_INSN. Some ports emit more
3129 than just a CALL_INSN above, so we must search for it here. */
3133 {
3135 /* There was no CALL_INSN? */
3138 }
3142 /* Stack adjustments after a noreturn call are dead code. */
3145 }
3150 /* If value type not void, return an rtx for the value. */
3152 /* If there are cleanups to be called, don't use a hard reg as target.
3153 We need to double check this and see if it matters anymore. */
3155 {
3160 }
3166 {
3168 {
3169 target
3172 structure_value_addr));
3174 }
3175 }
3177 {
3178 /* This is the special C++ case where we need to
3179 know what the true target was. We take care to
3180 never use this value more than once in one expression. */
3184 }
3185 /* Handle calls that return values in multiple non-contiguous locations.
3186 The Irix 6 ABI has examples of this. */
3188 {
3190 {
3191 /* This will only be assigned once, so it can be readonly. */
3198 }
3204 /* We can not support sibling calls for this case. */
3206 }
3210 {
3211 /* TARGET and VALREG cannot be equal at this point because the
3212 latter would not have REG_FUNCTION_VALUE_P true, while the
3213 former would if it were referring to the same register.
3215 If they refer to the same register, this move will be a no-op,
3216 except when function inlining is being done. */
3219 /* If we are setting a MEM, this code must be executed. Since it is
3220 emitted after the call insn, sibcall optimization cannot be
3221 performed in that case. */
3224 }
3226 {
3229 /* We can not support sibling calls for this case. */
3231 }
3232 else
3235 #ifdef PROMOTE_FUNCTION_RETURN
3236 /* If we promoted this return value, make the proper SUBREG. TARGET
3237 might be const0_rtx here, so be careful. */
3241 {
3246 /* If we don't promote as expected, something is wrong. */
3254 {
3261 }
3265 }
3266 #endif
3268 /* If size of args is variable or this was a constructor call for a stack
3269 argument, restore saved stack-pointer value. */
3272 {
3280 }
3282 {
3283 #ifdef REG_PARM_STACK_SPACE
3287 #endif
3289 /* If we saved any argument areas, restore them. */
3292 {
3294 rtx stack_area
3301 else
3304 BLOCK_OP_CALL_PARM);
3305 }
3309 }
3311 /* If this was alloca, record the new stack level for nonlocal gotos.
3312 Check for the handler slots since we might not have a save area
3313 for non-local gotos. */
3318 /* Free up storage we no longer need. */
3324 {
3325 /* Undo the fake expand_start_target_temps we did earlier. If
3326 there had been any cleanups created, we've already set
3327 sibcall_failure. */
3329 }
3331 /* If this function is returning into a memory location marked as
3332 readonly, it means it is initializing that location. We normally treat
3333 functions as not clobbering such locations, so we need to specify that
3334 this one does. We do this by adding the appropriate CLOBBER to the
3335 CALL_INSN function usage list. This cannot be done by emitting a
3336 standalone CLOBBER after the call because the latter would be ignored
3337 by at least the delay slot scheduling pass. We do this now instead of
3338 adding to call_fusage before the call to emit_call_1 because TARGET
3339 may be modified in the meantime. */
3342 add_function_usage_to
3345 NULL_RTX));
3351 {
3354 /* Restore the pending stack adjustment now that we have
3355 finished generating the sibling call sequence. */
3360 /* Prepare arg structure for next iteration. */
3362 {
3366 }
3369 }
3370 else
3371 {
3374 /* Verify that we've deallocated all the stack we used. */
3379 }
3381 /* If something prevents making this a sibling call,
3382 zero out the sequence. */
3385 }
3387 /* The function optimize_sibling_and_tail_recursive_calls doesn't
3388 handle CALL_PLACEHOLDERs inside other CALL_PLACEHOLDERs. This
3389 can happen if the arguments to this function call an inline
3390 function who's expansion contains another CALL_PLACEHOLDER.
3392 If there are any C_Ps in any of these sequences, replace them
3393 with their normal call. */
3410 /* If this was a potential tail recursion site, then emit a
3411 CALL_PLACEHOLDER with the normal and the tail recursion streams.
3412 One of them will be selected later. */
3414 {
3415 /* The tail recursion label must be kept around. We could expose
3416 its use in the CALL_PLACEHOLDER, but that creates unwanted edges
3417 and makes determining true tail recursion sites difficult.
3419 So we set LABEL_PRESERVE_P here, then clear it when we select
3420 one of the call sequences after rtl generation is complete. */
3424 tail_call_insns,
3425 tail_recursion_insns,
3426 tail_recursion_label));
3427 }
3428 else
3431 currently_expanding_call--;
3433 /* If this function returns with the stack pointer depressed, ensure
3434 this block saves and restores the stack pointer, show it was
3435 changed, and adjust for any outgoing arg space. */
3437 {
3442 }
3445 }
3447 /* Traverse an argument list in VALUES and expand all complex
3448 arguments into their components. */
3449 tree
3451 {
3452 tree p;
3457 {
3459 tree complex_type;
3466 {
3467 tree subtype;
3481 /* Skip the newly created node. */
3483 }
3484 }
3487 }
3489 /* Traverse a list of TYPES and expand all complex types into their
3490 components. */
3491 tree
3493 {
3494 tree p;
3499 {
3503 {
3506 /* Rewrite complex type with component type. */
3510 /* Add another component type for the imaginary part. */
3515 /* Skip the newly created node. */
3517 }
3518 }
3521 }
3522 \f
3523 /* Output a library call to function FUN (a SYMBOL_REF rtx).
3524 The RETVAL parameter specifies whether return value needs to be saved, other
3525 parameters are documented in the emit_library_call function below. */
3527 static rtx
3531 {
3532 /* Total size in bytes of all the stack-parms scanned so far. */
3534 /* Size of arguments before any adjustments (such as rounding). */
3537 rtx fun;
3541 CUMULATIVE_ARGS args_so_far;
3542 struct arg
3543 {
3544 rtx value;
3546 rtx reg;
3549 rtx save_area;
3550 };
3555 rtx valreg;
3561 rtx before_call;
3564 #ifdef REG_PARM_STACK_SPACE
3565 /* Define the boundary of the register parm stack space that needs to be
3566 save, if any. */
3569 #endif
3571 /* Size of the stack reserved for parameter registers. */
3575 #ifdef REG_PARM_STACK_SPACE
3576 #ifdef MAYBE_REG_PARM_STACK_SPACE
3578 #else
3580 #endif
3581 #endif
3583 /* By default, library functions can not throw. */
3587 {
3614 }
3617 /* Ensure current function's preferred stack boundary is at least
3618 what we need. */
3622 /* If this kind of value comes back in memory,
3623 decide where in memory it should come back. */
3625 {
3628 {
3629 #ifdef PCC_STATIC_STRUCT_RETURN
3630 rtx pointer_reg
3640 else
3642 #endif
3643 /* This call returns a big structure. */
3645 }
3646 }
3647 else
3650 /* ??? Unfinished: must pass the memory address as an argument. */
3652 /* Copy all the libcall-arguments out of the varargs data
3653 and into a vector ARGVEC.
3655 Compute how to pass each argument. We only support a very small subset
3656 of the full argument passing conventions to limit complexity here since
3657 library functions shouldn't have many args. */
3662 #ifdef INIT_CUMULATIVE_LIBCALL_ARGS
3664 #else
3666 #endif
3673 /* Now we are about to start emitting insns that can be deleted
3674 if a libcall is deleted. */
3680 /* If there's a structure value address to be passed,
3681 either pass it in the special place, or pass it as an extra argument. */
3683 {
3685 nargs++;
3687 /* Make sure it is a reasonable operand for a move or push insn. */
3697 #ifdef FUNCTION_ARG_PARTIAL_NREGS
3700 #endif
3703 #ifdef STACK_PARMS_IN_REG_PARM_AREA
3705 #else
3707 #endif
3716 count++;
3717 }
3720 {
3724 /* We cannot convert the arg value to the mode the library wants here;
3725 must do it earlier where we know the signedness of the arg. */
3730 /* On some machines, there's no way to pass a float to a library fcn.
3731 Pass it as a double instead. */
3732 #ifdef LIBGCC_NEEDS_DOUBLE
3735 #endif
3737 /* There's no need to call protect_from_queue, because
3738 either emit_move_insn or emit_push_insn will do that. */
3740 /* Make sure it is a reasonable operand for a move or push insn. */
3745 #ifdef FUNCTION_ARG_PASS_BY_REFERENCE
3747 {
3748 rtx slot;
3750 #ifdef FUNCTION_ARG_CALLEE_COPIES
3753 #endif
3754 ;
3756 /* loop.c won't look at CALL_INSN_FUNCTION_USAGE of const/pure
3757 functions, so we have to pretend this isn't such a function. */
3759 {
3763 }
3766 /* If this was a CONST function, it is now PURE since
3767 it now reads memory. */
3769 {
3772 }
3777 {
3781 }
3782 else
3783 {
3786 slot
3792 }
3796 call_fusage);
3800 slot),
3801 call_fusage);
3805 }
3806 #endif
3813 #ifdef FUNCTION_ARG_PARTIAL_NREGS
3816 #else
3818 #endif
3821 #ifdef STACK_PARMS_IN_REG_PARM_AREA
3823 #else
3825 #endif
3837 }
3839 #ifdef FINAL_REG_PARM_STACK_SPACE
3842 #endif
3843 /* If this machine requires an external definition for library
3844 functions, write one out. */
3849 + stack_pointer_delta
3851 / STACK_BYTES
3856 reg_parm_stack_space);
3858 #ifndef OUTGOING_REG_PARM_STACK_SPACE
3860 #endif
3866 {
3867 /* Since the stack pointer will never be pushed, it is possible for
3868 the evaluation of a parm to clobber something we have already
3869 written to the stack. Since most function calls on RISC machines
3870 do not use the stack, this is uncommon, but must work correctly.
3872 Therefore, we save any area of the stack that was already written
3873 and that we are using. Here we set up to do this by making a new
3874 stack usage map from the old one.
3876 Another approach might be to try to reorder the argument
3877 evaluations to avoid this conflicting stack usage. */
3881 #ifndef OUTGOING_REG_PARM_STACK_SPACE
3882 /* Since we will be writing into the entire argument area, the
3883 map must be allocated for its entire size, not just the part that
3884 is the responsibility of the caller. */
3886 #endif
3888 #ifdef ARGS_GROW_DOWNWARD
3891 #else
3893 needed);
3894 #endif
3899 initial_highest_arg_in_use);
3906 /* We must be careful to use virtual regs before they're instantiated,
3907 and real regs afterwards. Loop optimization, for example, can create
3908 new libcalls after we've instantiated the virtual regs, and if we
3909 use virtuals anyway, they won't match the rtl patterns. */
3913 else
3915 }
3916 else
3917 {
3920 }
3922 /* If we push args individually in reverse order, perform stack alignment
3923 before the first push (the last arg). */
3929 {
3932 }
3933 else
3934 {
3937 }
3939 #ifdef REG_PARM_STACK_SPACE
3941 {
3942 /* The argument list is the property of the called routine and it
3943 may clobber it. If the fixed area has been used for previous
3944 parameters, we must save and restore it. */
3947 }
3948 #endif
3950 /* Push the args that need to be pushed. */
3952 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
3953 are to be pushed. */
3955 {
3963 {
3965 {
3966 /* If this is being stored into a pre-allocated, fixed-size,
3967 stack area, save any previous data at that location. */
3969 #ifdef ARGS_GROW_DOWNWARD
3970 /* stack_slot is negative, but we want to index stack_usage_map
3971 with positive values. */
3974 #else
3977 #endif
3980 /* Don't worry about things in the fixed argument area;
3981 it has already been saved. */
3985 i++;
3988 {
3989 /* We need to make a save area. */
3990 unsigned int size
3992 enum machine_mode save_mode
3994 rtx adr
3997 rtx stack_area
4002 }
4003 }
4008 reg_parm_stack_space,
4011 /* Now mark the segment we just used. */
4016 NO_DEFER_POP;
4017 }
4018 }
4020 /* If we pushed args in forward order, perform stack alignment
4021 after pushing the last arg. */
4028 else
4033 /* Now load any reg parms into their regs. */
4035 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
4036 are to be pushed. */
4038 {
4043 /* Handle calls that pass values in multiple non-contiguous
4044 locations. The PA64 has examples of this for library calls. */
4050 NO_DEFER_POP;
4051 }
4053 /* Any regs containing parms remain in use through the call. */
4055 {
4061 }
4063 /* Pass the function the address in which to return a structure value. */
4065 {
4069 NULL_RTX)));
4072 }
4074 /* Don't allow popping to be deferred, since then
4075 cse'ing of library calls could delete a call and leave the pop. */
4076 NO_DEFER_POP;
4080 /* Stack must be properly aligned now. */
4086 /* We pass the old value of inhibit_defer_pop + 1 to emit_call_1, which
4087 will set inhibit_defer_pop to that value. */
4088 /* The return type is needed to decide how many bytes the function pops.
4089 Signedness plays no role in that, so for simplicity, we pretend it's
4090 always signed. We also assume that the list of arguments passed has
4091 no impact, so we pretend it is unknown. */
4097 struct_value_size,
4099 valreg,
4102 /* For calls to `setjmp', etc., inform flow.c it should complain
4103 if nonvolatile values are live. For functions that cannot return,
4104 inform flow that control does not fall through. */
4107 {
4108 /* The barrier note must be emitted
4109 immediately after the CALL_INSN. Some ports emit more than
4110 just a CALL_INSN above, so we must search for it here. */
4114 {
4116 /* There was no CALL_INSN? */
4119 }
4122 }
4124 /* Now restore inhibit_defer_pop to its actual original value. */
4125 OK_DEFER_POP;
4127 /* If call is cse'able, make appropriate pair of reg-notes around it.
4128 Test valreg so we don't crash; may safely ignore `const'
4129 if return type is void. Disable for PARALLEL return values, because
4130 we have no way to move such values into a pseudo register. */
4132 {
4133 rtx insns;
4136 {
4140 }
4141 else
4142 {
4144 rtx temp;
4148 {
4152 }
4156 /* Construct an "equal form" for the value which mentions all the
4157 arguments in order as well as the function name. */
4170 note);
4175 }
4176 }
4179 /* Copy the value to the right place. */
4181 {
4183 {
4188 }
4190 {
4194 }
4197 else
4199 }
4202 {
4203 #ifdef REG_PARM_STACK_SPACE
4207 #endif
4209 /* If we saved any argument areas, restore them. */
4212 {
4220 }
4224 }
4228 }
4229 \f
4230 /* Output a library call to function FUN (a SYMBOL_REF rtx)
4231 (emitting the queue unless NO_QUEUE is nonzero),
4232 for a value of mode OUTMODE,
4233 with NARGS different arguments, passed as alternating rtx values
4234 and machine_modes to convert them to.
4235 The rtx values should have been passed through protect_from_queue already.
4237 FN_TYPE should be LCT_NORMAL for `normal' calls, LCT_CONST for `const'
4238 calls, LCT_PURE for `pure' calls, LCT_CONST_MAKE_BLOCK for `const' calls
4239 which should be enclosed in REG_LIBCALL/REG_RETVAL notes,
4240 LCT_PURE_MAKE_BLOCK for `purep' calls which should be enclosed in
4241 REG_LIBCALL/REG_RETVAL notes with extra (use (memory (scratch)),
4242 or other LCT_ value for other types of library calls. */
4244 void
4247 {
4253 }
4254 \f
4255 /* Like emit_library_call except that an extra argument, VALUE,
4256 comes second and says where to store the result.
4257 (If VALUE is zero, this function chooses a convenient way
4258 to return the value.
4260 This function returns an rtx for where the value is to be found.
4261 If VALUE is nonzero, VALUE is returned. */
4263 rtx
4267 {
4268 rtx result;
4277 }
4278 \f
4279 /* Store a single argument for a function call
4280 into the register or memory area where it must be passed.
4281 *ARG describes the argument value and where to pass it.
4283 ARGBLOCK is the address of the stack-block for all the arguments,
4284 or 0 on a machine where arguments are pushed individually.
4286 MAY_BE_ALLOCA nonzero says this could be a call to `alloca'
4287 so must be careful about how the stack is used.
4289 VARIABLE_SIZE nonzero says that this was a variable-sized outgoing
4290 argument stack. This is used if ACCUMULATE_OUTGOING_ARGS to indicate
4291 that we need not worry about saving and restoring the stack.
4293 FNDECL is the declaration of the function we are calling.
4295 Return nonzero if this arg should cause sibcall failure,
4296 zero otherwise. */
4298 static int
4301 {
4312 /* Push a new temporary level for any temporaries we make for
4313 this argument. */
4317 {
4318 /* If this is being stored into a pre-allocated, fixed-size, stack area,
4319 save any previous data at that location. */
4321 {
4322 #ifdef ARGS_GROW_DOWNWARD
4323 /* stack_slot is negative, but we want to index stack_usage_map
4324 with positive values. */
4327 else
4331 #else
4334 else
4338 #endif
4341 /* Don't worry about things in the fixed argument area;
4342 it has already been saved. */
4346 i++;
4349 {
4350 /* We need to make a save area. */
4357 {
4366 BLOCK_OP_CALL_PARM);
4367 }
4368 else
4369 {
4372 }
4373 }
4374 }
4375 }
4377 /* If this isn't going to be placed on both the stack and in registers,
4378 set up the register and number of words. */
4380 {
4383 else
4386 }
4389 /* Being passed entirely in a register. We shouldn't be called in
4390 this case. */
4393 /* If this arg needs special alignment, don't load the registers
4394 here. */
4398 /* If this is being passed partially in a register, we can't evaluate
4399 it directly into its stack slot. Otherwise, we can. */
4401 {
4402 /* stack_arg_under_construction is nonzero if a function argument is
4403 being evaluated directly into the outgoing argument list and
4404 expand_call must take special action to preserve the argument list
4405 if it is called recursively.
4407 For scalar function arguments stack_usage_map is sufficient to
4408 determine which stack slots must be saved and restored. Scalar
4409 arguments in general have pass_on_stack == 0.
4411 If this argument is initialized by a function which takes the
4412 address of the argument (a C++ constructor or a C function
4413 returning a BLKmode structure), then stack_usage_map is
4414 insufficient and expand_call must push the stack around the
4415 function call. Such arguments have pass_on_stack == 1.
4417 Note that it is always safe to set stack_arg_under_construction,
4418 but this generates suboptimal code if set when not needed. */
4421 stack_arg_under_construction++;
4424 (partial
4429 /* If we are promoting object (or for any other reason) the mode
4430 doesn't agree, convert the mode. */
4437 stack_arg_under_construction--;
4438 }
4440 /* Don't allow anything left on stack from computation
4441 of argument to alloca. */
4446 /* If the value is already in the stack slot, we are done. */
4447 ;
4449 {
4452 /* Argument is a scalar, not entirely passed in registers.
4453 (If part is passed in registers, arg->partial says how much
4454 and emit_push_insn will take care of putting it there.)
4456 Push it, and if its size is less than the
4457 amount of space allocated to it,
4458 also bump stack pointer by the additional space.
4459 Note that in C the default argument promotions
4460 will prevent such mismatches. */
4463 /* Compute how much space the push instruction will push.
4464 On many machines, pushing a byte will advance the stack
4465 pointer by a halfword. */
4466 #ifdef PUSH_ROUNDING
4468 #endif
4471 /* Compute how much space the argument should get:
4472 round up to a multiple of the alignment for arguments. */
4478 /* This isn't already where we want it on the stack, so put it there.
4479 This can either be done with push or copy insns. */
4485 /* Unless this is a partially-in-register argument, the argument is now
4486 in the stack. */
4489 }
4490 else
4491 {
4492 /* BLKmode, at least partly to be pushed. */
4496 rtx size_rtx;
4498 /* Pushing a nonscalar.
4499 If part is passed in registers, PARTIAL says how much
4500 and emit_push_insn will take care of putting it there. */
4502 /* Round its size up to a multiple
4503 of the allocation unit for arguments. */
4506 {
4509 }
4510 else
4511 {
4512 /* PUSH_ROUNDING has no effect on us, because
4513 emit_push_insn for BLKmode is careful to avoid it. */
4519 }
4521 /* Some types will require stricter alignment, which will be
4522 provided for elsewhere in argument layout. */
4525 /* When an argument is padded down, the block is aligned to
4526 PARM_BOUNDARY, but the actual argument isn't. */
4528 {
4532 {
4535 }
4536 }
4539 {
4540 /* emit_push_insn might not work properly if arg->value and
4541 argblock + arg->locate.offset areas overlap. */
4548 current_function_internal_arg_pointer
4550 {
4554 /* expand_call should ensure this */
4559 {
4562 }
4564 {
4567 }
4568 }
4569 }
4576 /* Unless this is a partially-in-register argument, the argument is now
4577 in the stack.
4579 ??? Unlike the case above, in which we want the actual
4580 address of the data, so that we can load it directly into a
4581 register, here we want the address of the stack slot, so that
4582 it's properly aligned for word-by-word copying or something
4583 like that. It's not clear that this is always correct. */
4586 }
4588 /* Mark all slots this store used. */
4594 /* Once we have pushed something, pops can't safely
4595 be deferred during the rest of the arguments. */
4596 NO_DEFER_POP;
4598 /* ANSI doesn't require a sequence point here,
4599 but PCC has one, so this will avoid some problems. */
4602 /* Free any temporary slots made in processing this argument. Show
4603 that we might have taken the address of something and pushed that
4604 as an operand. */
4610 }
4612 /* Nonzero if we do not know how to pass TYPE solely in registers.
4613 We cannot do so in the following cases:
4615 - if the type has variable size
4616 - if the type is marked as addressable (it is required to be constructed
4617 into the stack)
4618 - if the padding and mode of the type is such that a copy into a register
4619 would put it into the wrong part of the register.
4621 Which padding can't be supported depends on the byte endianness.
4623 A value in a register is implicitly padded at the most significant end.
4624 On a big-endian machine, that is the lower end in memory.
4625 So a value padded in memory at the upper end can't go in a register.
4626 For a little-endian machine, the reverse is true. */
4628 bool
4630 {
4634 /* If the type has variable size... */
4638 /* If the type is marked as addressable (it is required
4639 to be constructed into the stack)... */
4643 /* If the padding and mode of the type is such that a copy into
4644 a register would put it into the wrong part of the register. */
4652 }