| blob | d6032fc78bcac4b1cc34bcce2753d2087c7a3448 |
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, 2004, 2005
4 Free Software Foundation, Inc.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 2, or (at your option) any later
11 version.
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING. If not, write to the Free
20 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
21 02111-1307, USA. */
45 /* Like PREFERRED_STACK_BOUNDARY but in units of bytes, not bits. */
46 #define STACK_BYTES (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT)
48 /* Data structure and subroutines used within expand_call. */
50 struct arg_data
51 {
52 /* Tree node for this argument. */
53 tree tree_value;
54 /* Mode for value; TYPE_MODE unless promoted. */
56 /* Current RTL value for argument, or 0 if it isn't precomputed. */
57 rtx value;
58 /* Initially-compute RTL value for argument; only for const functions. */
59 rtx initial_value;
60 /* Register to pass this argument in, 0 if passed on stack, or an
61 PARALLEL if the arg is to be copied into multiple non-contiguous
62 registers. */
63 rtx reg;
64 /* Register to pass this argument in when generating tail call sequence.
65 This is not the same register as for normal calls on machines with
66 register windows. */
67 rtx tail_call_reg;
68 /* If REG is a PARALLEL, this is a copy of VALUE pulled into the correct
69 form for emit_group_move. */
70 rtx parallel_value;
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. */
126 CUMULATIVE_ARGS *);
154 #ifdef REG_PARM_STACK_SPACE
157 #endif
158 \f
159 /* Force FUNEXP into a form suitable for the address of a CALL,
160 and return that as an rtx. Also load the static chain register
161 if FNDECL is a nested function.
163 CALL_FUSAGE points to a variable holding the prospective
164 CALL_INSN_FUNCTION_USAGE information. */
166 rtx
169 {
170 /* Make a valid memory address and copy constants through pseudo-regs,
171 but not for a constant address if -fno-function-cse. */
173 /* If we are using registers for parameters, force the
174 function address into a register now. */
179 {
180 #ifndef NO_FUNCTION_CSE
183 #endif
184 }
187 {
193 }
196 }
198 /* Generate instructions to call function FUNEXP,
199 and optionally pop the results.
200 The CALL_INSN is the first insn generated.
202 FNDECL is the declaration node of the function. This is given to the
203 macro RETURN_POPS_ARGS to determine whether this function pops its own args.
205 FUNTYPE is the data type of the function. This is given to the macro
206 RETURN_POPS_ARGS to determine whether this function pops its own args.
207 We used to allow an identifier for library functions, but that doesn't
208 work when the return type is an aggregate type and the calling convention
209 says that the pointer to this aggregate is to be popped by the callee.
211 STACK_SIZE is the number of bytes of arguments on the stack,
212 ROUNDED_STACK_SIZE is that number rounded up to
213 PREFERRED_STACK_BOUNDARY; zero if the size is variable. This is
214 both to put into the call insn and to generate explicit popping
215 code if necessary.
217 STRUCT_VALUE_SIZE is the number of bytes wanted in a structure value.
218 It is zero if this call doesn't want a structure value.
220 NEXT_ARG_REG is the rtx that results from executing
221 FUNCTION_ARG (args_so_far, VOIDmode, void_type_node, 1)
222 just after all the args have had their registers assigned.
223 This could be whatever you like, but normally it is the first
224 arg-register beyond those used for args in this call,
225 or 0 if all the arg-registers are used in this call.
226 It is passed on to `gen_call' so you can put this info in the call insn.
228 VALREG is a hard register in which a value is returned,
229 or 0 if the call does not return a value.
231 OLD_INHIBIT_DEFER_POP is the value that `inhibit_defer_pop' had before
232 the args to this call were processed.
233 We restore `inhibit_defer_pop' to that value.
235 CALL_FUSAGE is either empty or an EXPR_LIST of USE expressions that
236 denote registers used by the called function. */
238 static void
240 tree funtype ATTRIBUTE_UNUSED,
241 HOST_WIDE_INT stack_size ATTRIBUTE_UNUSED,
242 HOST_WIDE_INT rounded_stack_size,
243 HOST_WIDE_INT struct_value_size ATTRIBUTE_UNUSED,
247 {
249 rtx call_insn;
252 #if defined (HAVE_call) && defined (HAVE_call_value)
253 rtx struct_value_size_rtx;
255 #endif
257 #ifdef CALL_POPS_ARGS
259 #endif
261 /* Ensure address is valid. SYMBOL_REF is already valid, so no need,
262 and we don't want to load it into a register as an optimization,
263 because prepare_call_address already did it if it should be done. */
267 #if defined (HAVE_sibcall_pop) && defined (HAVE_sibcall_value_pop)
271 {
273 rtx pat;
275 /* If this subroutine pops its own args, record that in the call insn
276 if possible, for the sake of frame pointer elimination. */
282 n_pop);
283 else
289 }
290 else
291 #endif
293 #if defined (HAVE_call_pop) && defined (HAVE_call_value_pop)
294 /* If the target has "call" or "call_value" insns, then prefer them
295 if no arguments are actually popped. If the target does not have
296 "call" or "call_value" insns, then we must use the popping versions
297 even if the call has no arguments to pop. */
298 #if defined (HAVE_call) && defined (HAVE_call_value)
301 #else
303 #endif
304 {
306 rtx pat;
308 /* If this subroutine pops its own args, record that in the call insn
309 if possible, for the sake of frame pointer elimination. */
315 else
321 }
322 else
323 #endif
325 #if defined (HAVE_sibcall) && defined (HAVE_sibcall_value)
328 {
332 rounded_stack_size_rtx,
334 else
337 struct_value_size_rtx));
338 }
339 else
340 #endif
342 #if defined (HAVE_call) && defined (HAVE_call_value)
344 {
349 NULL_RTX));
350 else
353 struct_value_size_rtx));
354 }
355 else
356 #endif
359 /* Find the call we just emitted. */
362 /* Mark memory as used for "pure" function call. */
364 call_fusage
365 = gen_rtx_EXPR_LIST
369 call_fusage);
371 /* Put the register usage information there. */
374 /* If this is a const call, then set the insn's unchanging bit. */
378 /* If this call can't throw, attach a REG_EH_REGION reg note to that
379 effect. */
383 else
384 {
387 /* If rn < 0, then either (1) tree-ssa not used or (2) doesn't
388 throw, which we already took care of. */
393 }
400 {
404 }
408 /* Restore this now, so that we do defer pops for this call's args
409 if the context of the call as a whole permits. */
413 {
422 }
425 {
426 /* If returning from the subroutine does not automatically pop the args,
427 we need an instruction to pop them sooner or later.
428 Perhaps do it now; perhaps just record how much space to pop later.
430 If returning from the subroutine does pop the args, indicate that the
431 stack pointer will be changed. */
434 {
436 /* Just pretend we did the pop. */
441 else
443 }
444 }
445 /* When we accumulate outgoing args, we must avoid any stack manipulations.
446 Restore the stack pointer to its original value now. Usually
447 ACCUMULATE_OUTGOING_ARGS targets don't get here, but there are exceptions.
448 On i386 ACCUMULATE_OUTGOING_ARGS can be enabled on demand, and
449 popping variants of functions exist as well.
451 ??? We may optimize similar to defer_pop above, but it is
452 probably not worthwhile.
454 ??? It will be worthwhile to enable combine_stack_adjustments even for
455 such machines. */
458 }
460 /* Determine if the function identified by NAME and FNDECL is one with
461 special properties we wish to know about.
463 For example, if the function might return more than one time (setjmp), then
464 set RETURNS_TWICE to a nonzero value.
466 Similarly set LONGJMP for if the function is in the longjmp family.
468 Set MAY_BE_ALLOCA for any memory allocation function that might allocate
469 space from the stack such as alloca. */
471 static int
473 {
476 /* Exclude functions not at the file scope, or not `extern',
477 since they are not the magic functions we would otherwise
478 think they are.
479 FIXME: this should be handled with attributes, not with this
480 hacky imitation of DECL_ASSEMBLER_NAME. It's (also) wrong
481 because you can declare fork() inside a function if you
482 wish. */
486 {
490 /* We assume that alloca will always be called by name. It
491 makes no sense to pass it as a pointer-to-function to
492 anything that does not understand its behavior. */
501 /* Disregard prefix _, __ or __x. */
503 {
508 else
510 }
513 {
526 }
536 }
539 }
541 /* Return nonzero when tree represent call to longjmp. */
543 int
545 {
547 }
549 /* Return true when exp contains alloca call. */
550 bool
552 {
561 }
563 /* Detect flags (function attributes) from the function decl or type node. */
565 int
567 {
572 {
577 {
582 }
584 /* The function exp may have the `malloc' attribute. */
588 /* The function exp may have the `returns_twice' attribute. */
592 /* The function exp may have the `pure' attribute. */
603 }
610 /* Mark if the function returns with the stack pointer depressed. We
611 cannot consider it pure or constant in that case. */
613 {
616 }
619 }
621 /* Detect flags from a CALL_EXPR. */
623 int
625 {
631 else
632 {
636 else
638 }
641 }
643 /* Precompute all register parameters as described by ARGS, storing values
644 into fields within the ARGS array.
646 NUM_ACTUALS indicates the total number elements in the ARGS array.
648 Set REG_PARM_SEEN if we encounter a register parameter. */
650 static void
653 {
660 {
664 {
670 }
672 /* If the value is a non-legitimate constant, force it into a
673 pseudo now. TLS symbols sometimes need a call to resolve. */
678 /* If we are to promote the function arg to a wider mode,
679 do it now. */
687 /* If we're going to have to load the value by parts, pull the
688 parts into pseudos. The part extraction process can involve
689 non-trivial computation. */
691 {
696 }
698 /* If the value is expensive, and we are inside an appropriately
699 short loop, put the value into a pseudo and then put the pseudo
700 into the hard reg.
702 For small register classes, also do this if this call uses
703 register parameters. This is to avoid reload conflicts while
704 loading the parameters registers. */
714 }
715 }
717 #ifdef REG_PARM_STACK_SPACE
719 /* The argument list is the property of the called routine and it
720 may clobber it. If the fixed area has been used for previous
721 parameters, we must save and restore it. */
723 static rtx
724 save_fixed_argument_area (int reg_parm_stack_space, rtx argblock, int *low_to_save, int *high_to_save)
725 {
729 /* Compute the boundary of the area that needs to be saved, if any. */
731 #ifdef ARGS_GROW_DOWNWARD
733 #endif
739 {
743 rtx stack_area;
744 rtx save_area;
747 ;
755 /* If we don't have the required alignment, must do this
756 in BLKmode. */
761 #ifdef ARGS_GROW_DOWNWARD
763 #else
765 #endif
769 delta)));
773 {
777 }
778 else
779 {
782 }
785 }
788 }
790 static void
792 {
795 rtx stack_area;
797 #ifdef ARGS_GROW_DOWNWARD
799 #else
801 #endif
809 else
812 BLOCK_OP_CALL_PARM);
813 }
816 /* If any elements in ARGS refer to parameters that are to be passed in
817 registers, but not in memory, and whose alignment does not permit a
818 direct copy into registers. Copy the values into a group of pseudos
819 which we will later copy into the appropriate hard registers.
821 Pseudos for each unaligned argument will be stored into the array
822 args[argnum].aligned_regs. The caller is responsible for deallocating
823 the aligned_regs array if it is nonzero. */
825 static void
827 {
835 {
840 {
843 }
844 else
845 {
848 }
852 /* Structures smaller than a word are normally aligned to the
853 least significant byte. On a BYTES_BIG_ENDIAN machine,
854 this means we must skip the empty high order bytes when
855 calculating the bit offset. */
857 #ifdef BLOCK_REG_PADDING
861 #else
862 && BYTES_BIG_ENDIAN
863 #endif
864 )
868 {
877 /* There is no need to restrict this code to loading items
878 in TYPE_ALIGN sized hunks. The bitfield instructions can
879 load up entire word sized registers efficiently.
881 ??? This may not be needed anymore.
882 We use to emit a clobber here but that doesn't let later
883 passes optimize the instructions we emit. By storing 0 into
884 the register later passes know the first AND to zero out the
885 bitfield being set in the register is unnecessary. The store
886 of 0 will be deleted as will at least the first AND. */
892 word);
893 }
894 }
895 }
897 /* Fill in ARGS_SIZE and ARGS array based on the parameters found in
898 ACTPARMS.
900 NUM_ACTUALS is the total number of parameters.
902 N_NAMED_ARGS is the total number of named arguments.
904 FNDECL is the tree code for the target of this call (if known)
906 ARGS_SO_FAR holds state needed by the target to know where to place
907 the next argument.
909 REG_PARM_STACK_SPACE is the number of bytes of stack space reserved
910 for arguments which are passed in registers.
912 OLD_STACK_LEVEL is a pointer to an rtx which olds the old stack level
913 and may be modified by this routine.
915 OLD_PENDING_ADJ, MUST_PREALLOCATE and FLAGS are pointers to integer
916 flags which may may be modified by this routine.
918 MAY_TAILCALL is cleared if we encounter an invisible pass-by-reference
919 that requires allocation of stack space.
921 CALL_FROM_THUNK_P is true if this call is the jump from a thunk to
922 the thunked-to function. */
924 static void
935 {
936 /* 1 if scanning parms front to back, -1 if scanning back to front. */
939 /* Count arg position in order args appear. */
943 tree p;
948 /* In this loop, we consider args in the order they are written.
949 We fill up ARGS from the front or from the back if necessary
950 so that in any case the first arg to be pushed ends up at the front. */
953 {
955 /* In this case, must reverse order of args
956 so that we compute and push the last arg first. */
957 }
958 else
959 {
961 }
963 /* I counts args in order (to be) pushed; ARGPOS counts in order written. */
965 {
972 /* Replace erroneous argument with constant zero. */
976 /* If TYPE is a transparent union, pass things the way we would
977 pass the first field of the union. We have already verified that
978 the modes are the same. */
982 /* Decide where to pass this arg.
984 args[i].reg is nonzero if all or part is passed in registers.
986 args[i].partial is nonzero if part but not all is passed in registers,
987 and the exact value says how many bytes are passed in registers.
989 args[i].pass_on_stack is nonzero if the argument must at least be
990 computed on the stack. It may then be loaded back into registers
991 if args[i].reg is nonzero.
993 These decisions are driven by the FUNCTION_... macros and must agree
994 with those made by function.c. */
996 /* See if this argument should be passed by invisible reference. */
999 {
1001 tree base;
1003 callee_copies
1007 /* If we're compiling a thunk, pass through invisible references
1008 instead of making a copy. */
1010 || (callee_copies
1014 {
1015 /* We can't use sibcalls if a callee-copied argument is
1016 stored in the current function's frame. */
1024 }
1025 else
1026 {
1027 /* We make a copy of the object and pass the address to the
1028 function being called. */
1029 rtx copy;
1035 STACK_CHECK_MAX_VAR_SIZE))))
1036 {
1037 /* This is a variable-sized object. Make space on the stack
1038 for it. */
1042 {
1046 }
1049 allocate_dynamic_stack_space
1052 }
1053 else
1060 else
1067 }
1068 }
1081 #ifdef FUNCTION_INCOMING_ARG
1082 /* If this is a sibling call and the machine has register windows, the
1083 register window has to be unwinded before calling the routine, so
1084 arguments have to go into the incoming registers. */
1087 #else
1089 #endif
1098 /* If FUNCTION_ARG returned a (parallel [(expr_list (nil) ...) ...]),
1099 it means that we are to pass this arg in the register(s) designated
1100 by the PARALLEL, but also to pass it in the stack. */
1105 /* If this is an addressable type, we must preallocate the stack
1106 since we must evaluate the object into its final location.
1108 If this is to be passed in both registers and the stack, it is simpler
1109 to preallocate. */
1114 /* If this is an addressable type, we cannot pre-evaluate it. Thus,
1115 we cannot consider this function call constant. */
1119 /* Compute the stack-size of this argument. */
1124 #ifdef STACK_PARMS_IN_REG_PARM_AREA
1126 #else
1128 #endif
1131 #ifdef BLOCK_REG_PADDING
1132 else
1133 /* The argument is passed entirely in registers. See at which
1134 end it should be padded. */
1138 #endif
1140 /* Update ARGS_SIZE, the total stack space for args so far. */
1146 /* Increment ARGS_SO_FAR, which has info about which arg-registers
1147 have been used, etc. */
1151 }
1152 }
1154 /* Update ARGS_SIZE to contain the total size for the argument block.
1155 Return the original constant component of the argument block's size.
1157 REG_PARM_STACK_SPACE holds the number of bytes of stack space reserved
1158 for arguments passed in registers. */
1160 static int
1164 {
1167 /* For accumulate outgoing args mode we don't need to align, since the frame
1168 will be already aligned. Align to STACK_BOUNDARY in order to prevent
1169 backends from generating misaligned frame sizes. */
1173 /* Compute the actual size of the argument block required. The variable
1174 and constant sizes must be combined, the size may have to be rounded,
1175 and there may be a minimum required size. */
1178 {
1184 {
1185 /* We don't handle this case yet. To handle it correctly we have
1186 to add the delta, round and subtract the delta.
1187 Currently no machine description requires this support. */
1190 }
1193 {
1194 args_size->var
1198 #ifndef OUTGOING_REG_PARM_STACK_SPACE
1199 /* The area corresponding to register parameters is not to count in
1200 the size of the block we need. So make the adjustment. */
1201 args_size->var
1204 #endif
1205 }
1206 }
1207 else
1208 {
1213 + stack_pointer_delta
1215 / preferred_stack_boundary
1220 reg_parm_stack_space);
1222 #ifndef OUTGOING_REG_PARM_STACK_SPACE
1224 #endif
1225 }
1227 }
1229 /* Precompute parameters as needed for a function call.
1231 FLAGS is mask of ECF_* constants.
1233 NUM_ACTUALS is the number of arguments.
1235 ARGS is an array containing information for each argument; this
1236 routine fills in the INITIAL_VALUE and VALUE fields for each
1237 precomputed argument. */
1239 static void
1241 {
1244 /* If this is a libcall, then precompute all arguments so that we do not
1245 get extraneous instructions emitted as part of the libcall sequence. */
1250 {
1253 /* If this is an addressable type, we cannot pre-evaluate it. */
1261 {
1265 #if defined(PROMOTE_FUNCTION_MODE) && !defined(PROMOTE_MODE)
1266 /* CSE will replace this only if it contains args[i].value
1267 pseudo, so convert it down to the declared mode using
1268 a SUBREG. */
1271 {
1277 }
1278 #endif
1279 }
1280 }
1281 }
1283 /* Given the current state of MUST_PREALLOCATE and information about
1284 arguments to a function call in NUM_ACTUALS, ARGS and ARGS_SIZE,
1285 compute and return the final value for MUST_PREALLOCATE. */
1287 static int
1288 finalize_must_preallocate (int must_preallocate, int num_actuals, struct arg_data *args, struct args_size *args_size)
1289 {
1290 /* See if we have or want to preallocate stack space.
1292 If we would have to push a partially-in-regs parm
1293 before other stack parms, preallocate stack space instead.
1295 If the size of some parm is not a multiple of the required stack
1296 alignment, we must preallocate.
1298 If the total size of arguments that would otherwise create a copy in
1299 a temporary (such as a CALL) is more than half the total argument list
1300 size, preallocation is faster.
1302 Another reason to preallocate is if we have a machine (like the m88k)
1303 where stack alignment is required to be maintained between every
1304 pair of insns, not just when the call is made. However, we assume here
1305 that such machines either do not have push insns (and hence preallocation
1306 would occur anyway) or the problem is taken care of with
1307 PUSH_ROUNDING. */
1310 {
1316 {
1327 copy_to_evaluate_size
1329 }
1334 }
1336 }
1338 /* If we preallocated stack space, compute the address of each argument
1339 and store it into the ARGS array.
1341 We need not ensure it is a valid memory address here; it will be
1342 validized when it is used.
1344 ARGBLOCK is an rtx for the address of the outgoing arguments. */
1346 static void
1348 {
1350 {
1358 {
1361 rtx addr;
1364 /* Skip this parm if it will not be passed on the stack. */
1370 else
1382 {
1385 }
1390 else
1399 /* Function incoming arguments may overlap with sibling call
1400 outgoing arguments and we cannot allow reordering of reads
1401 from function arguments with stores to outgoing arguments
1402 of sibling calls. */
1405 }
1406 }
1407 }
1409 /* Given a FNDECL and EXP, return an rtx suitable for use as a target address
1410 in a call instruction.
1412 FNDECL is the tree node for the target function. For an indirect call
1413 FNDECL will be NULL_TREE.
1415 ADDR is the operand 0 of CALL_EXPR for this call. */
1417 static rtx
1419 {
1420 rtx funexp;
1422 /* Get the function to call, in the form of RTL. */
1424 {
1425 /* If this is the first use of the function, see if we need to
1426 make an external definition for it. */
1428 {
1431 }
1433 /* Get a SYMBOL_REF rtx for the function address. */
1435 }
1436 else
1437 /* Generate an rtx (probably a pseudo-register) for the address. */
1438 {
1442 }
1444 }
1446 /* Do the register loads required for any wholly-register parms or any
1447 parms which are passed both on the stack and in a register. Their
1448 expressions were already evaluated.
1450 Mark all register-parms as living through the call, putting these USE
1451 insns in the CALL_INSN_FUNCTION_USAGE field.
1453 When IS_SIBCALL, perform the check_sibcall_overlap_argument_overlap
1454 checking, setting *SIBCALL_FAILURE if appropriate. */
1456 static void
1460 {
1464 {
1468 {
1473 /* Set to non-negative if must move a word at a time, even if just
1474 one word (e.g, partial == 1 && mode == DFmode). Set to -1 if
1475 we just use a normal move insn. This value can be zero if the
1476 argument is a zero size structure with no fields. */
1479 ;
1481 {
1484 }
1486 {
1489 }
1490 else
1493 /* Handle calls that pass values in multiple non-contiguous
1494 locations. The Irix 6 ABI has examples of this. */
1499 /* If simple case, just do move. If normal partial, store_one_arg
1500 has already loaded the register for us. In all other cases,
1501 load the register(s) from memory. */
1504 {
1506 #ifdef BLOCK_REG_PADDING
1507 /* Handle case where we have a value that needs shifting
1508 up to the msb. eg. a QImode value and we're padding
1509 upward on a BYTES_BIG_ENDIAN machine. */
1513 {
1514 rtx x;
1517 /* Assigning REG here rather than a temp makes CALL_FUSAGE
1518 report the whole reg as used. Strictly speaking, the
1519 call only uses SIZE bytes at the msb end, but it doesn't
1520 seem worth generating rtl to say that. */
1527 }
1528 #endif
1529 }
1531 /* If we have pre-computed the values to put in the registers in
1532 the case of non-aligned structures, copy them in now. */
1540 {
1543 /* Handle a BLKmode that needs shifting. */
1545 #ifdef BLOCK_REG_PADDING
1547 #else
1548 && BYTES_BIG_ENDIAN
1549 #endif
1550 )
1551 {
1565 }
1566 else
1568 }
1570 /* When a parameter is a block, and perhaps in other cases, it is
1571 possible that it did a load from an argument slot that was
1572 already clobbered. */
1577 /* Handle calls that pass values in multiple non-contiguous
1578 locations. The Irix 6 ABI has examples of this. */
1585 }
1586 }
1587 }
1589 /* We need to pop PENDING_STACK_ADJUST bytes. But, if the arguments
1590 wouldn't fill up an even multiple of PREFERRED_UNIT_STACK_BOUNDARY
1591 bytes, then we would need to push some additional bytes to pad the
1592 arguments. So, we compute an adjust to the stack pointer for an
1593 amount that will leave the stack under-aligned by UNADJUSTED_ARGS_SIZE
1594 bytes. Then, when the arguments are pushed the stack will be perfectly
1595 aligned. ARGS_SIZE->CONSTANT is set to the number of bytes that should
1596 be popped after the call. Returns the adjustment. */
1598 static int
1602 {
1603 /* The number of bytes to pop so that the stack will be
1604 under-aligned by UNADJUSTED_ARGS_SIZE bytes. */
1605 HOST_WIDE_INT adjustment;
1606 /* The alignment of the stack after the arguments are pushed, if we
1607 just pushed the arguments without adjust the stack here. */
1610 unadjusted_alignment
1614 /* We want to get rid of as many of the PENDING_STACK_ADJUST bytes
1615 as possible -- leaving just enough left to cancel out the
1616 UNADJUSTED_ALIGNMENT. In other words, we want to ensure that the
1617 PENDING_STACK_ADJUST is non-negative, and congruent to
1618 -UNADJUSTED_ALIGNMENT modulo the PREFERRED_UNIT_STACK_BOUNDARY. */
1620 /* Begin by trying to pop all the bytes. */
1621 unadjusted_alignment
1622 = (unadjusted_alignment
1625 /* Push enough additional bytes that the stack will be aligned
1626 after the arguments are pushed. */
1628 {
1631 else
1633 }
1635 /* Now, sets ARGS_SIZE->CONSTANT so that we pop the right number of
1636 bytes after the call. The right number is the entire
1637 PENDING_STACK_ADJUST less our ADJUSTMENT plus the amount required
1638 by the arguments in the first place. */
1639 args_size->constant
1643 }
1645 /* Scan X expression if it does not dereference any argument slots
1646 we already clobbered by tail call arguments (as noted in stored_args_map
1647 bitmap).
1648 Return nonzero if X expression dereferences such argument slots,
1649 zero otherwise. */
1651 static int
1653 {
1654 RTX_CODE code;
1665 {
1670 current_function_internal_arg_pointer
1673 else
1676 #ifdef ARGS_GROW_DOWNWARD
1678 #endif
1686 }
1688 /* Scan all subexpressions. */
1691 {
1693 {
1696 }
1698 {
1702 }
1703 }
1705 }
1707 /* Scan sequence after INSN if it does not dereference any argument slots
1708 we already clobbered by tail call arguments (as noted in stored_args_map
1709 bitmap). If MARK_STORED_ARGS_MAP, add stack slots for ARG to
1710 stored_args_map bitmap afterwards (when ARG is a register MARK_STORED_ARGS_MAP
1711 should be 0). Return nonzero if sequence after INSN dereferences such argument
1712 slots, zero otherwise. */
1714 static int
1716 {
1721 else
1730 {
1731 #ifdef ARGS_GROW_DOWNWARD
1733 #else
1735 #endif
1739 }
1741 }
1743 /* Given that a function returns a value of mode MODE at the most
1744 significant end of hard register VALUE, shift VALUE left or right
1745 as specified by LEFT_P. Return true if some action was needed. */
1747 bool
1749 {
1750 HOST_WIDE_INT shift;
1757 /* Use ashr rather than lshr for right shifts. This is for the benefit
1758 of the MIPS port, which requires SImode values to be sign-extended
1759 when stored in 64-bit registers. */
1764 }
1766 /* Remove all REG_EQUIV notes found in the insn chain. */
1768 static void
1770 {
1771 rtx insn;
1774 {
1776 {
1779 {
1780 /* Remove the note and keep looking at the notes for
1781 this insn. */
1784 }
1786 }
1787 }
1788 }
1790 /* Generate all the code for a function call
1791 and return an rtx for its value.
1792 Store the value in TARGET (specified as an rtx) if convenient.
1793 If the value is stored in TARGET then TARGET is returned.
1794 If IGNORE is nonzero, then we ignore the value of the function call. */
1796 rtx
1798 {
1799 /* Nonzero if we are currently expanding a call. */
1802 /* List of actual parameters. */
1804 /* RTX for the function to be called. */
1805 rtx funexp;
1806 /* Sequence of insns to perform a normal "call". */
1808 /* Sequence of insns to perform a tail "call". */
1810 /* Data type of the function. */
1811 tree funtype;
1812 tree type_arg_types;
1813 /* Declaration of the function being called,
1814 or 0 if the function is computed (not known by name). */
1816 /* The type of the function being called. */
1817 tree fntype;
1821 /* Register in which non-BLKmode value will be returned,
1822 or 0 if no value or if value is BLKmode. */
1823 rtx valreg;
1824 /* Address where we should return a BLKmode value;
1825 0 if value not BLKmode. */
1827 /* Nonzero if that address is being passed by treating it as
1828 an extra, implicit first parameter. Otherwise,
1829 it is passed by being copied directly into struct_value_rtx. */
1831 /* Size of aggregate value wanted, or zero if none wanted
1832 or if we are using the non-reentrant PCC calling convention
1833 or expecting the value in registers. */
1835 /* Nonzero if called function returns an aggregate in memory PCC style,
1836 by returning the address of where to find it. */
1840 /* Number of actual parameters in this call, including struct value addr. */
1842 /* Number of named args. Args after this are anonymous ones
1843 and they must all go on the stack. */
1846 /* Vector of information about each argument.
1847 Arguments are numbered in the order they will be pushed,
1848 not the order they are written. */
1851 /* Total size in bytes of all the stack-parms scanned so far. */
1854 /* Size of arguments before any adjustments (such as rounding). */
1856 /* Data on reg parms scanned so far. */
1857 CUMULATIVE_ARGS args_so_far;
1858 /* Nonzero if a reg parm has been scanned. */
1860 /* Nonzero if this is an indirect function call. */
1862 /* Nonzero if we must avoid push-insns in the args for this call.
1863 If stack space is allocated for register parameters, but not by the
1864 caller, then it is preallocated in the fixed part of the stack frame.
1865 So the entire argument block must then be preallocated (i.e., we
1866 ignore PUSH_ROUNDING in that case). */
1870 /* Size of the stack reserved for parameter registers. */
1873 /* Address of space preallocated for stack parms
1874 (on machines that lack push insns), or 0 if space not preallocated. */
1877 /* Mask of ECF_ flags. */
1879 #ifdef REG_PARM_STACK_SPACE
1880 /* Define the boundary of the register parm stack space that needs to be
1881 saved, if any. */
1884 #endif
1891 /* State variables to track stack modifications. */
1897 /* Some stack pointer alterations we make are performed via
1898 allocate_dynamic_stack_space. This modifies the stack_pointer_delta,
1899 which we then also need to save/restore along the way. */
1902 rtx call_fusage;
1906 /* The alignment of the stack, in bits. */
1908 /* The alignment of the stack, in bytes. */
1910 /* The static chain value to use for this call. */
1911 rtx static_chain_value;
1912 /* See if this is "nothrow" function call. */
1916 /* See if we can find a DECL-node for the actual function, and get the
1917 function attributes (flags) from the function decl or type node. */
1920 {
1923 }
1924 else
1925 {
1928 }
1932 /* Warn if this value is an aggregate type,
1933 regardless of which calling convention we are using for it. */
1937 /* If the result of a pure or const function call is ignored (or void),
1938 and none of its arguments are volatile, we can avoid expanding the
1939 call and just evaluate the arguments for side-effects. */
1943 {
1945 tree arg;
1949 {
1952 }
1955 {
1960 }
1961 }
1963 #ifdef REG_PARM_STACK_SPACE
1965 #endif
1967 #ifndef OUTGOING_REG_PARM_STACK_SPACE
1970 #endif
1972 /* Set up a place to return a structure. */
1974 /* Cater to broken compilers. */
1976 {
1977 /* This call returns a big structure. */
1980 #ifdef PCC_STATIC_STRUCT_RETURN
1981 {
1983 }
1985 {
1989 {
1990 /* The structure value address arg is already in actparms.
1991 Pull it out. It might be nice to just leave it there, but
1992 we need to set structure_value_addr. */
1997 }
2000 else
2001 {
2002 /* For variable-sized objects, we must be called with a target
2003 specified. If we were to allocate space on the stack here,
2004 we would have no way of knowing when to free it. */
2010 }
2011 }
2013 }
2015 /* Figure out the amount to which the stack should be aligned. */
2018 {
2022 }
2024 /* Operand 0 is a pointer-to-function; get the type of the function. */
2029 /* Munge the tree to split complex arguments into their imaginary
2030 and real parts. */
2032 {
2035 }
2036 else
2042 /* If struct_value_rtx is 0, it means pass the address
2043 as if it were an extra parameter. */
2045 {
2046 /* If structure_value_addr is a REG other than
2047 virtual_outgoing_args_rtx, we can use always use it. If it
2048 is not a REG, we must always copy it into a register.
2049 If it is virtual_outgoing_args_rtx, we must copy it to another
2050 register in some cases. */
2052 || (ACCUMULATE_OUTGOING_ARGS
2053 && stack_arg_under_construction
2059 actparms
2062 temp),
2063 actparms);
2065 }
2067 /* Count the arguments and set NUM_ACTUALS. */
2069 num_actuals++;
2071 /* Compute number of named args.
2072 First, do a raw count of the args for INIT_CUMULATIVE_ARGS. */
2075 n_named_args
2077 /* Count the struct value address, if it is passed as a parm. */
2079 else
2080 /* If we know nothing, treat all args as named. */
2083 /* Start updating where the next arg would go.
2085 On some machines (such as the PA) indirect calls have a different
2086 calling convention than normal calls. The fourth argument in
2087 INIT_CUMULATIVE_ARGS tells the backend if this is an indirect call
2088 or not. */
2091 /* Now possibly adjust the number of named args.
2092 Normally, don't include the last named arg if anonymous args follow.
2093 We do include the last named arg if
2094 targetm.calls.strict_argument_naming() returns nonzero.
2095 (If no anonymous args follow, the result of list_length is actually
2096 one too large. This is harmless.)
2098 If targetm.calls.pretend_outgoing_varargs_named() returns
2099 nonzero, and targetm.calls.strict_argument_naming() returns zero,
2100 this machine will be able to place unnamed args that were passed
2101 in registers into the stack. So treat all args as named. This
2102 allows the insns emitting for a specific argument list to be
2103 independent of the function declaration.
2105 If targetm.calls.pretend_outgoing_varargs_named() returns zero,
2106 we do not have any reliable way to pass unnamed args in
2107 registers, so we must force them into memory. */
2111 ;
2114 /* Don't include the last named arg. */
2116 else
2117 /* Treat all args as named. */
2120 /* Make a vector to hold all the information about each arg. */
2124 /* Build up entries in the ARGS array, compute the size of the
2125 arguments into ARGS_SIZE, etc. */
2134 {
2135 /* If this function requires a variable-sized argument list, don't
2136 try to make a cse'able block for this call. We may be able to
2137 do this eventually, but it is too complicated to keep track of
2138 what insns go in the cse'able block and which don't. */
2142 }
2144 /* Now make final decision about preallocating stack space. */
2149 /* If the structure value address will reference the stack pointer, we
2150 must stabilize it. We don't need to do this if we know that we are
2151 not going to adjust the stack pointer in processing this call. */
2156 structure_value_addr))
2161 /* Tail calls can make things harder to debug, and we've traditionally
2162 pushed these optimizations into -O2. Don't try if we're already
2163 expanding a call, as that means we're an argument. Don't try if
2164 there's cleanups, as we know there's code to follow the call. */
2167 || !flag_optimize_sibling_calls
2172 /* Rest of purposes for tail call optimizations to fail. */
2174 #ifdef HAVE_sibcall_epilogue
2175 !HAVE_sibcall_epilogue
2176 #else
2177 1
2178 #endif
2179 || !try_tail_call
2180 /* Doing sibling call optimization needs some work, since
2181 structure_value_addr can be allocated on the stack.
2182 It does not seem worth the effort since few optimizable
2183 sibling calls will return a structure. */
2185 /* Check whether the target is able to optimize the call
2186 into a sibcall. */
2188 /* Functions that do not return exactly once may not be sibcall
2189 optimized. */
2192 /* If the called function is nested in the current one, it might access
2193 some of the caller's arguments, but could clobber them beforehand if
2194 the argument areas are shared. */
2196 /* If this function requires more stack slots than the current
2197 function, we cannot change it into a sibling call. */
2199 /* If the callee pops its own arguments, then it must pop exactly
2200 the same number of arguments as the current function. */
2204 current_function_args_size))
2208 /* Ensure current function's preferred stack boundary is at least
2209 what we need. We don't have to increase alignment for recursive
2210 functions. */
2219 /* We want to make two insn chains; one for a sibling call, the other
2220 for a normal call. We will select one of the two chains after
2221 initial RTL generation is complete. */
2223 {
2225 /* We want to emit any pending stack adjustments before the tail
2226 recursion "call". That way we know any adjustment after the tail
2227 recursion call can be ignored if we indeed use the tail
2228 call expansion. */
2231 rtx insns;
2235 {
2236 /* State variables we need to save and restore between
2237 iterations. */
2240 }
2243 else
2246 /* Other state variables that we must reinitialize each time
2247 through the loop (that are not initialized by the loop itself). */
2251 /* Start a new sequence for the normal call case.
2253 From this point on, if the sibling call fails, we want to set
2254 sibcall_failure instead of continuing the loop. */
2257 /* Don't let pending stack adjusts add up to too much.
2258 Also, do all pending adjustments now if there is any chance
2259 this might be a call to alloca or if we are expanding a sibling
2260 call sequence or if we are calling a function that is to return
2261 with stack pointer depressed. */
2268 /* When calling a const function, we must pop the stack args right away,
2269 so that the pop is deleted or moved with the call. */
2271 NO_DEFER_POP;
2273 /* Precompute any arguments as needed. */
2277 /* Now we are about to start emitting insns that can be deleted
2278 if a libcall is deleted. */
2283 /* Compute the actual size of the argument block required. The variable
2284 and constant sizes must be combined, the size may have to be rounded,
2285 and there may be a minimum required size. When generating a sibcall
2286 pattern, do not round up, since we'll be re-using whatever space our
2287 caller provided. */
2288 unadjusted_args_size
2296 /* The argument block when performing a sibling call is the
2297 incoming argument block. */
2299 {
2301 argblock
2302 #ifdef STACK_GROWS_DOWNWARD
2304 #else
2306 #endif
2309 }
2311 /* If we have no actual push instructions, or shouldn't use them,
2312 make space for all args right now. */
2314 {
2316 {
2321 /* stack_arg_under_construction says whether a stack arg is
2322 being constructed at the old stack level. Pushing the stack
2323 gets a clean outgoing argument block. */
2326 }
2328 }
2329 else
2330 {
2331 /* Note that we must go through the motions of allocating an argument
2332 block even if the size is zero because we may be storing args
2333 in the area reserved for register arguments, which may be part of
2334 the stack frame. */
2338 /* Store the maximum argument space used. It will be pushed by
2339 the prologue (if ACCUMULATE_OUTGOING_ARGS, or stack overflow
2340 checking). */
2346 {
2348 {
2349 /* Since the stack pointer will never be pushed, it is
2350 possible for the evaluation of a parm to clobber
2351 something we have already written to the stack.
2352 Since most function calls on RISC machines do not use
2353 the stack, this is uncommon, but must work correctly.
2355 Therefore, we save any area of the stack that was already
2356 written and that we are using. Here we set up to do this
2357 by making a new stack usage map from the old one. The
2358 actual save will be done by store_one_arg.
2360 Another approach might be to try to reorder the argument
2361 evaluations to avoid this conflicting stack usage. */
2363 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2364 /* Since we will be writing into the entire argument area,
2365 the map must be allocated for its entire size, not just
2366 the part that is the responsibility of the caller. */
2368 #endif
2370 #ifdef ARGS_GROW_DOWNWARD
2373 #else
2375 needed);
2376 #endif
2381 initial_highest_arg_in_use);
2385 (highest_outgoing_arg_in_use
2389 /* The address of the outgoing argument list must not be
2390 copied to a register here, because argblock would be left
2391 pointing to the wrong place after the call to
2392 allocate_dynamic_stack_space below. */
2395 }
2396 else
2397 {
2399 {
2400 /* Try to reuse some or all of the pending_stack_adjust
2401 to get this space. */
2402 needed
2403 = (combine_pending_stack_adjustment_and_call
2406 preferred_unit_stack_boundary));
2408 /* combine_pending_stack_adjustment_and_call computes
2409 an adjustment before the arguments are allocated.
2410 Account for them and see whether or not the stack
2411 needs to go up or down. */
2415 {
2416 /* We're releasing stack space. */
2417 /* ??? We can avoid any adjustment at all if we're
2418 already aligned. FIXME. */
2422 }
2423 else
2424 /* We need to allocate space. We'll do that in
2425 push_block below. */
2427 }
2429 /* Special case this because overhead of `push_block' in
2430 this case is non-trivial. */
2433 else
2434 {
2436 #ifdef ARGS_GROW_DOWNWARD
2438 #endif
2439 }
2441 /* We only really need to call `copy_to_reg' in the case
2442 where push insns are going to be used to pass ARGBLOCK
2443 to a function call in ARGS. In that case, the stack
2444 pointer changes value from the allocation point to the
2445 call point, and hence the value of
2446 VIRTUAL_OUTGOING_ARGS_RTX changes as well. But might
2447 as well always do it. */
2449 }
2450 }
2451 }
2454 {
2455 /* The save/restore code in store_one_arg handles all
2456 cases except one: a constructor call (including a C
2457 function returning a BLKmode struct) to initialize
2458 an argument. */
2460 {
2461 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2464 #else
2466 #endif
2468 {
2470 NULL_RTX);
2474 /* stack_arg_under_construction says whether a stack
2475 arg is being constructed at the old stack level.
2476 Pushing the stack gets a clean outgoing argument
2477 block. */
2478 old_stack_arg_under_construction
2481 /* Make a new map for the new argument list. */
2485 }
2487 BITS_PER_UNIT);
2488 }
2490 /* If argument evaluation might modify the stack pointer,
2491 copy the address of the argument list to a register. */
2494 {
2497 }
2498 }
2502 /* If we push args individually in reverse order, perform stack alignment
2503 before the first push (the last arg). */
2506 {
2507 /* When the stack adjustment is pending, we get better code
2508 by combining the adjustments. */
2512 {
2513 pending_stack_adjust
2514 = (combine_pending_stack_adjustment_and_call
2517 preferred_unit_stack_boundary));
2519 }
2523 }
2524 /* Now that the stack is properly aligned, pops can't safely
2525 be deferred during the evaluation of the arguments. */
2526 NO_DEFER_POP;
2530 /* Figure out the register where the value, if any, will come back. */
2534 {
2538 else
2540 }
2542 /* Precompute all register parameters. It isn't safe to compute anything
2543 once we have started filling any specific hard regs. */
2549 else
2552 #ifdef REG_PARM_STACK_SPACE
2553 /* Save the fixed argument area if it's part of the caller's frame and
2554 is clobbered by argument setup for this call. */
2558 #endif
2560 /* Now store (and compute if necessary) all non-register parms.
2561 These come before register parms, since they can require block-moves,
2562 which could clobber the registers used for register parms.
2563 Parms which have partial registers are not stored here,
2564 but we do preallocate space here if they want that. */
2568 {
2573 reg_parm_stack_space)
2585 call_fusage);
2586 }
2588 /* If we have a parm that is passed in registers but not in memory
2589 and whose alignment does not permit a direct copy into registers,
2590 make a group of pseudos that correspond to each register that we
2591 will later fill. */
2595 /* Now store any partially-in-registers parm.
2596 This is the last place a block-move can happen. */
2600 {
2605 reg_parm_stack_space)
2610 }
2612 /* If we pushed args in forward order, perform stack alignment
2613 after pushing the last arg. */
2618 /* If register arguments require space on the stack and stack space
2619 was not preallocated, allocate stack space here for arguments
2620 passed in registers. */
2621 #ifdef OUTGOING_REG_PARM_STACK_SPACE
2625 #endif
2627 /* Pass the function the address in which to return a
2628 structure value. */
2630 {
2631 structure_value_addr
2636 NULL_RTX)));
2640 }
2648 /* Save a pointer to the last insn before the call, so that we can
2649 later safely search backwards to find the CALL_INSN. */
2652 /* Set up next argument register. For sibling calls on machines
2653 with register windows this should be the incoming register. */
2654 #ifdef FUNCTION_INCOMING_ARG
2658 else
2659 #endif
2663 /* All arguments and registers used for the call must be set up by
2664 now! */
2666 /* Stack must be properly aligned now. */
2670 /* Generate the actual call instruction. */
2676 /* If a non-BLKmode value is returned at the most significant end
2677 of a register, shift the register right by the appropriate amount
2678 and update VALREG accordingly. BLKmode values are handled by the
2679 group load/store machinery below. */
2681 && !pcc_struct_value
2684 {
2688 }
2690 /* If call is cse'able, make appropriate pair of reg-notes around it.
2691 Test valreg so we don't crash; may safely ignore `const'
2692 if return type is void. Disable for PARALLEL return values, because
2693 we have no way to move such values into a pseudo register. */
2695 {
2696 rtx insns;
2697 rtx insn;
2702 /* Expansion of block moves possibly introduced a loop that may
2703 not appear inside libcall block. */
2709 {
2712 }
2713 else
2714 {
2718 /* Mark the return value as a pointer if needed. */
2725 && fndecl
2733 else
2734 {
2735 /* Construct an "equal form" for the value which
2736 mentions all the arguments in order as well as
2737 the function name. */
2748 note);
2749 }
2753 }
2754 }
2756 {
2760 /* The return value from a malloc-like function is a pointer. */
2766 /* The return value from a malloc-like function can not alias
2767 anything else. */
2772 /* Write out the sequence. */
2777 }
2779 /* For calls to `setjmp', etc., inform flow.c it should complain
2780 if nonvolatile values are live. For functions that cannot return,
2781 inform flow that control does not fall through. */
2784 {
2785 /* The barrier must be emitted
2786 immediately after the CALL_INSN. Some ports emit more
2787 than just a CALL_INSN above, so we must search for it here. */
2791 {
2793 /* There was no CALL_INSN? */
2795 }
2799 /* Stack adjustments after a noreturn call are dead code.
2800 However when NO_DEFER_POP is in effect, we must preserve
2801 stack_pointer_delta. */
2803 {
2806 }
2807 }
2809 /* If value type not void, return an rtx for the value. */
2815 {
2817 {
2818 target
2821 structure_value_addr));
2823 }
2824 }
2826 {
2827 /* This is the special C++ case where we need to
2828 know what the true target was. We take care to
2829 never use this value more than once in one expression. */
2833 }
2834 /* Handle calls that return values in multiple non-contiguous locations.
2835 The Irix 6 ABI has examples of this. */
2837 {
2839 {
2840 /* This will only be assigned once, so it can be readonly. */
2846 }
2852 /* We can not support sibling calls for this case. */
2854 }
2858 {
2859 /* TARGET and VALREG cannot be equal at this point because the
2860 latter would not have REG_FUNCTION_VALUE_P true, while the
2861 former would if it were referring to the same register.
2863 If they refer to the same register, this move will be a no-op,
2864 except when function inlining is being done. */
2867 /* If we are setting a MEM, this code must be executed. Since it is
2868 emitted after the call insn, sibcall optimization cannot be
2869 performed in that case. */
2872 }
2874 {
2877 /* We can not support sibling calls for this case. */
2879 }
2880 else
2884 {
2885 /* If we promoted this return value, make the proper SUBREG.
2886 TARGET might be const0_rtx here, so be careful. */
2890 {
2897 /* If we don't promote as expected, something is wrong. */
2903 {
2910 }
2914 }
2915 }
2917 /* If size of args is variable or this was a constructor call for a stack
2918 argument, restore saved stack-pointer value. */
2921 {
2930 }
2932 {
2933 #ifdef REG_PARM_STACK_SPACE
2937 #endif
2939 /* If we saved any argument areas, restore them. */
2942 {
2944 rtx stack_area
2951 else
2954 BLOCK_OP_CALL_PARM);
2955 }
2959 }
2961 /* If this was alloca, record the new stack level for nonlocal gotos.
2962 Check for the handler slots since we might not have a save area
2963 for non-local gotos. */
2968 /* Free up storage we no longer need. */
2977 {
2980 /* Restore the pending stack adjustment now that we have
2981 finished generating the sibling call sequence. */
2986 /* Prepare arg structure for next iteration. */
2988 {
2992 }
2995 }
2996 else
2997 {
3000 /* Verify that we've deallocated all the stack we used. */
3002 || (old_stack_allocated
3004 }
3006 /* If something prevents making this a sibling call,
3007 zero out the sequence. */
3010 else
3012 }
3014 /* If tail call production succeeded, we need to remove REG_EQUIV notes on
3015 arguments too, as argument area is now clobbered by the call. */
3017 {
3020 }
3021 else
3024 currently_expanding_call--;
3026 /* If this function returns with the stack pointer depressed, ensure
3027 this block saves and restores the stack pointer, show it was
3028 changed, and adjust for any outgoing arg space. */
3030 {
3034 }
3037 }
3039 /* A sibling call sequence invalidates any REG_EQUIV notes made for
3040 this function's incoming arguments.
3042 At the start of RTL generation we know the only REG_EQUIV notes
3043 in the rtl chain are those for incoming arguments, so we can safely
3044 flush any REG_EQUIV note.
3046 This is (slight) overkill. We could keep track of the highest
3047 argument we clobber and be more selective in removing notes, but it
3048 does not seem to be worth the effort. */
3049 void
3051 {
3053 }
3055 /* Traverse an argument list in VALUES and expand all complex
3056 arguments into their components. */
3057 static tree
3059 {
3060 tree p;
3062 /* Before allocating memory, check for the common case of no complex. */
3064 {
3069 }
3072 found:
3076 {
3078 tree complex_type;
3086 {
3087 tree subtype;
3101 /* Skip the newly created node. */
3103 }
3104 }
3107 }
3109 /* Traverse a list of TYPES and expand all complex types into their
3110 components. */
3111 static tree
3113 {
3114 tree p;
3116 /* Before allocating memory, check for the common case of no complex. */
3118 {
3123 }
3126 found:
3130 {
3135 {
3138 /* Rewrite complex type with component type. */
3142 /* Add another component type for the imaginary part. */
3147 /* Skip the newly created node. */
3149 }
3150 }
3153 }
3154 \f
3155 /* Output a library call to function FUN (a SYMBOL_REF rtx).
3156 The RETVAL parameter specifies whether return value needs to be saved, other
3157 parameters are documented in the emit_library_call function below. */
3159 static rtx
3163 {
3164 /* Total size in bytes of all the stack-parms scanned so far. */
3166 /* Size of arguments before any adjustments (such as rounding). */
3169 rtx fun;
3173 CUMULATIVE_ARGS args_so_far;
3174 struct arg
3175 {
3176 rtx value;
3178 rtx reg;
3181 rtx save_area;
3182 };
3187 rtx valreg;
3193 rtx before_call;
3196 #ifdef REG_PARM_STACK_SPACE
3197 /* Define the boundary of the register parm stack space that needs to be
3198 save, if any. */
3201 #endif
3203 /* Size of the stack reserved for parameter registers. */
3209 #ifdef REG_PARM_STACK_SPACE
3211 #endif
3213 /* By default, library functions can not throw. */
3217 {
3241 }
3244 /* Ensure current function's preferred stack boundary is at least
3245 what we need. */
3249 /* If this kind of value comes back in memory,
3250 decide where in memory it should come back. */
3252 {
3255 {
3256 #ifdef PCC_STATIC_STRUCT_RETURN
3257 rtx pointer_reg
3267 else
3269 #endif
3270 /* This call returns a big structure. */
3272 }
3273 }
3274 else
3277 /* ??? Unfinished: must pass the memory address as an argument. */
3279 /* Copy all the libcall-arguments out of the varargs data
3280 and into a vector ARGVEC.
3282 Compute how to pass each argument. We only support a very small subset
3283 of the full argument passing conventions to limit complexity here since
3284 library functions shouldn't have many args. */
3289 #ifdef INIT_CUMULATIVE_LIBCALL_ARGS
3291 #else
3293 #endif
3300 /* Now we are about to start emitting insns that can be deleted
3301 if a libcall is deleted. */
3307 /* If there's a structure value address to be passed,
3308 either pass it in the special place, or pass it as an extra argument. */
3310 {
3313 nargs++;
3315 /* Make sure it is a reasonable operand for a move or push insn. */
3329 #ifdef STACK_PARMS_IN_REG_PARM_AREA
3331 #else
3333 #endif
3342 count++;
3343 }
3346 {
3350 /* We cannot convert the arg value to the mode the library wants here;
3351 must do it earlier where we know the signedness of the arg. */
3355 /* Make sure it is a reasonable operand for a move or push insn. */
3361 {
3362 rtx slot;
3363 int must_copy
3366 /* loop.c won't look at CALL_INSN_FUNCTION_USAGE of const/pure
3367 functions, so we have to pretend this isn't such a function. */
3369 {
3373 }
3376 /* If this was a CONST function, it is now PURE since
3377 it now reads memory. */
3379 {
3382 }
3386 else
3387 {
3391 }
3395 call_fusage);
3399 slot),
3400 call_fusage);
3404 }
3415 #ifdef STACK_PARMS_IN_REG_PARM_AREA
3417 #else
3419 #endif
3430 }
3432 /* If this machine requires an external definition for library
3433 functions, write one out. */
3438 + stack_pointer_delta
3440 / STACK_BYTES
3445 reg_parm_stack_space);
3447 #ifndef OUTGOING_REG_PARM_STACK_SPACE
3449 #endif
3455 {
3456 /* Since the stack pointer will never be pushed, it is possible for
3457 the evaluation of a parm to clobber something we have already
3458 written to the stack. Since most function calls on RISC machines
3459 do not use the stack, this is uncommon, but must work correctly.
3461 Therefore, we save any area of the stack that was already written
3462 and that we are using. Here we set up to do this by making a new
3463 stack usage map from the old one.
3465 Another approach might be to try to reorder the argument
3466 evaluations to avoid this conflicting stack usage. */
3470 #ifndef OUTGOING_REG_PARM_STACK_SPACE
3471 /* Since we will be writing into the entire argument area, the
3472 map must be allocated for its entire size, not just the part that
3473 is the responsibility of the caller. */
3475 #endif
3477 #ifdef ARGS_GROW_DOWNWARD
3480 #else
3482 needed);
3483 #endif
3488 initial_highest_arg_in_use);
3495 /* We must be careful to use virtual regs before they're instantiated,
3496 and real regs afterwards. Loop optimization, for example, can create
3497 new libcalls after we've instantiated the virtual regs, and if we
3498 use virtuals anyway, they won't match the rtl patterns. */
3502 else
3504 }
3505 else
3506 {
3509 }
3511 /* If we push args individually in reverse order, perform stack alignment
3512 before the first push (the last arg). */
3518 {
3521 }
3522 else
3523 {
3526 }
3528 #ifdef REG_PARM_STACK_SPACE
3530 {
3531 /* The argument list is the property of the called routine and it
3532 may clobber it. If the fixed area has been used for previous
3533 parameters, we must save and restore it. */
3536 }
3537 #endif
3539 /* Push the args that need to be pushed. */
3541 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
3542 are to be pushed. */
3544 {
3552 {
3554 {
3555 /* If this is being stored into a pre-allocated, fixed-size,
3556 stack area, save any previous data at that location. */
3558 #ifdef ARGS_GROW_DOWNWARD
3559 /* stack_slot is negative, but we want to index stack_usage_map
3560 with positive values. */
3563 #else
3566 #endif
3569 /* Don't worry about things in the fixed argument area;
3570 it has already been saved. */
3574 i++;
3577 {
3578 /* We need to make a save area. */
3579 unsigned int size
3581 enum machine_mode save_mode
3583 rtx adr
3586 rtx stack_area
3590 {
3597 stack_area,
3599 BLOCK_OP_CALL_PARM);
3600 }
3601 else
3602 {
3606 }
3607 }
3608 }
3613 reg_parm_stack_space,
3616 /* Now mark the segment we just used. */
3621 NO_DEFER_POP;
3622 }
3623 }
3625 /* If we pushed args in forward order, perform stack alignment
3626 after pushing the last arg. */
3633 else
3638 /* Now load any reg parms into their regs. */
3640 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
3641 are to be pushed. */
3643 {
3649 /* Handle calls that pass values in multiple non-contiguous
3650 locations. The PA64 has examples of this for library calls. */
3656 NO_DEFER_POP;
3657 }
3659 /* Any regs containing parms remain in use through the call. */
3661 {
3667 }
3669 /* Pass the function the address in which to return a structure value. */
3671 {
3675 NULL_RTX)));
3678 }
3680 /* Don't allow popping to be deferred, since then
3681 cse'ing of library calls could delete a call and leave the pop. */
3682 NO_DEFER_POP;
3686 /* Stack must be properly aligned now. */
3692 /* We pass the old value of inhibit_defer_pop + 1 to emit_call_1, which
3693 will set inhibit_defer_pop to that value. */
3694 /* The return type is needed to decide how many bytes the function pops.
3695 Signedness plays no role in that, so for simplicity, we pretend it's
3696 always signed. We also assume that the list of arguments passed has
3697 no impact, so we pretend it is unknown. */
3703 struct_value_size,
3705 valreg,
3708 /* For calls to `setjmp', etc., inform flow.c it should complain
3709 if nonvolatile values are live. For functions that cannot return,
3710 inform flow that control does not fall through. */
3713 {
3714 /* The barrier note must be emitted
3715 immediately after the CALL_INSN. Some ports emit more than
3716 just a CALL_INSN above, so we must search for it here. */
3720 {
3722 /* There was no CALL_INSN? */
3724 }
3727 }
3729 /* Now restore inhibit_defer_pop to its actual original value. */
3730 OK_DEFER_POP;
3732 /* If call is cse'able, make appropriate pair of reg-notes around it.
3733 Test valreg so we don't crash; may safely ignore `const'
3734 if return type is void. Disable for PARALLEL return values, because
3735 we have no way to move such values into a pseudo register. */
3737 {
3738 rtx insns;
3741 {
3745 }
3746 else
3747 {
3749 rtx temp;
3753 {
3758 }
3762 /* Construct an "equal form" for the value which mentions all the
3763 arguments in order as well as the function name. */
3776 note);
3781 }
3782 }
3785 /* Copy the value to the right place. */
3787 {
3789 {
3794 }
3796 {
3800 }
3803 else
3805 }
3808 {
3809 #ifdef REG_PARM_STACK_SPACE
3813 #endif
3815 /* If we saved any argument areas, restore them. */
3818 {
3829 BLOCK_OP_CALL_PARM);
3830 else
3832 }
3836 }
3840 }
3841 \f
3842 /* Output a library call to function FUN (a SYMBOL_REF rtx)
3843 (emitting the queue unless NO_QUEUE is nonzero),
3844 for a value of mode OUTMODE,
3845 with NARGS different arguments, passed as alternating rtx values
3846 and machine_modes to convert them to.
3848 FN_TYPE should be LCT_NORMAL for `normal' calls, LCT_CONST for `const'
3849 calls, LCT_PURE for `pure' calls, LCT_CONST_MAKE_BLOCK for `const' calls
3850 which should be enclosed in REG_LIBCALL/REG_RETVAL notes,
3851 LCT_PURE_MAKE_BLOCK for `purep' calls which should be enclosed in
3852 REG_LIBCALL/REG_RETVAL notes with extra (use (memory (scratch)),
3853 or other LCT_ value for other types of library calls. */
3855 void
3858 {
3864 }
3865 \f
3866 /* Like emit_library_call except that an extra argument, VALUE,
3867 comes second and says where to store the result.
3868 (If VALUE is zero, this function chooses a convenient way
3869 to return the value.
3871 This function returns an rtx for where the value is to be found.
3872 If VALUE is nonzero, VALUE is returned. */
3874 rtx
3878 {
3879 rtx result;
3888 }
3889 \f
3890 /* Store a single argument for a function call
3891 into the register or memory area where it must be passed.
3892 *ARG describes the argument value and where to pass it.
3894 ARGBLOCK is the address of the stack-block for all the arguments,
3895 or 0 on a machine where arguments are pushed individually.
3897 MAY_BE_ALLOCA nonzero says this could be a call to `alloca'
3898 so must be careful about how the stack is used.
3900 VARIABLE_SIZE nonzero says that this was a variable-sized outgoing
3901 argument stack. This is used if ACCUMULATE_OUTGOING_ARGS to indicate
3902 that we need not worry about saving and restoring the stack.
3904 FNDECL is the declaration of the function we are calling.
3906 Return nonzero if this arg should cause sibcall failure,
3907 zero otherwise. */
3909 static int
3912 {
3923 /* Push a new temporary level for any temporaries we make for
3924 this argument. */
3928 {
3929 /* If this is being stored into a pre-allocated, fixed-size, stack area,
3930 save any previous data at that location. */
3932 {
3933 #ifdef ARGS_GROW_DOWNWARD
3934 /* stack_slot is negative, but we want to index stack_usage_map
3935 with positive values. */
3938 else
3942 #else
3945 else
3949 #endif
3952 /* Don't worry about things in the fixed argument area;
3953 it has already been saved. */
3957 i++;
3960 {
3961 /* We need to make a save area. */
3968 {
3977 BLOCK_OP_CALL_PARM);
3978 }
3979 else
3980 {
3983 }
3984 }
3985 }
3986 }
3988 /* If this isn't going to be placed on both the stack and in registers,
3989 set up the register and number of words. */
3991 {
3994 else
3997 }
3999 /* Being passed entirely in a register. We shouldn't be called in
4000 this case. */
4003 /* If this arg needs special alignment, don't load the registers
4004 here. */
4008 /* If this is being passed partially in a register, we can't evaluate
4009 it directly into its stack slot. Otherwise, we can. */
4011 {
4012 /* stack_arg_under_construction is nonzero if a function argument is
4013 being evaluated directly into the outgoing argument list and
4014 expand_call must take special action to preserve the argument list
4015 if it is called recursively.
4017 For scalar function arguments stack_usage_map is sufficient to
4018 determine which stack slots must be saved and restored. Scalar
4019 arguments in general have pass_on_stack == 0.
4021 If this argument is initialized by a function which takes the
4022 address of the argument (a C++ constructor or a C function
4023 returning a BLKmode structure), then stack_usage_map is
4024 insufficient and expand_call must push the stack around the
4025 function call. Such arguments have pass_on_stack == 1.
4027 Note that it is always safe to set stack_arg_under_construction,
4028 but this generates suboptimal code if set when not needed. */
4031 stack_arg_under_construction++;
4034 (partial
4039 /* If we are promoting object (or for any other reason) the mode
4040 doesn't agree, convert the mode. */
4047 stack_arg_under_construction--;
4048 }
4050 /* Don't allow anything left on stack from computation
4051 of argument to alloca. */
4056 /* If the value is already in the stack slot, we are done. */
4057 ;
4059 {
4062 /* Argument is a scalar, not entirely passed in registers.
4063 (If part is passed in registers, arg->partial says how much
4064 and emit_push_insn will take care of putting it there.)
4066 Push it, and if its size is less than the
4067 amount of space allocated to it,
4068 also bump stack pointer by the additional space.
4069 Note that in C the default argument promotions
4070 will prevent such mismatches. */
4073 /* Compute how much space the push instruction will push.
4074 On many machines, pushing a byte will advance the stack
4075 pointer by a halfword. */
4076 #ifdef PUSH_ROUNDING
4078 #endif
4081 /* Compute how much space the argument should get:
4082 round up to a multiple of the alignment for arguments. */
4088 /* This isn't already where we want it on the stack, so put it there.
4089 This can either be done with push or copy insns. */
4095 /* Unless this is a partially-in-register argument, the argument is now
4096 in the stack. */
4099 }
4100 else
4101 {
4102 /* BLKmode, at least partly to be pushed. */
4106 rtx size_rtx;
4108 /* Pushing a nonscalar.
4109 If part is passed in registers, PARTIAL says how much
4110 and emit_push_insn will take care of putting it there. */
4112 /* Round its size up to a multiple
4113 of the allocation unit for arguments. */
4116 {
4119 }
4120 else
4121 {
4122 /* PUSH_ROUNDING has no effect on us, because emit_push_insn
4123 for BLKmode is careful to avoid it. */
4129 }
4133 /* When an argument is padded down, the block is aligned to
4134 PARM_BOUNDARY, but the actual argument isn't. */
4136 {
4140 {
4143 }
4144 }
4147 {
4148 /* emit_push_insn might not work properly if arg->value and
4149 argblock + arg->locate.offset areas overlap. */
4156 current_function_internal_arg_pointer
4158 {
4162 /* expand_call should ensure this. */
4167 {
4170 }
4172 {
4175 }
4176 }
4177 }
4184 /* Unless this is a partially-in-register argument, the argument is now
4185 in the stack.
4187 ??? Unlike the case above, in which we want the actual
4188 address of the data, so that we can load it directly into a
4189 register, here we want the address of the stack slot, so that
4190 it's properly aligned for word-by-word copying or something
4191 like that. It's not clear that this is always correct. */
4194 }
4197 {
4199 arg->parallel_value
4202 }
4204 /* Mark all slots this store used. */
4210 /* Once we have pushed something, pops can't safely
4211 be deferred during the rest of the arguments. */
4212 NO_DEFER_POP;
4214 /* Free any temporary slots made in processing this argument. Show
4215 that we might have taken the address of something and pushed that
4216 as an operand. */
4222 }
4224 /* Nonzero if we do not know how to pass TYPE solely in registers. */
4226 bool
4228 tree type)
4229 {
4233 /* If the type has variable size... */
4237 /* If the type is marked as addressable (it is required
4238 to be constructed into the stack)... */
4243 }
4245 /* Another version of the TARGET_MUST_PASS_IN_STACK hook. This one
4246 takes trailing padding of a structure into account. */
4247 /* ??? Should be able to merge these two by examining BLOCK_REG_PADDING. */
4249 bool
4251 {
4255 /* If the type has variable size... */
4259 /* If the type is marked as addressable (it is required
4260 to be constructed into the stack)... */
4264 /* If the padding and mode of the type is such that a copy into
4265 a register would put it into the wrong part of the register. */
4273 }