| blob | e4c3d9f3037c832e676bb92a6fa7c9726db72d89 |
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 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 /* Like PREFERRED_STACK_BOUNDARY but in units of bytes, not bits. */
45 #define STACK_BYTES (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT)
47 /* Data structure and subroutines used within expand_call. */
49 struct arg_data
50 {
51 /* Tree node for this argument. */
52 tree tree_value;
53 /* Mode for value; TYPE_MODE unless promoted. */
55 /* Current RTL value for argument, or 0 if it isn't precomputed. */
56 rtx value;
57 /* Initially-compute RTL value for argument; only for const functions. */
58 rtx initial_value;
59 /* Register to pass this argument in, 0 if passed on stack, or an
60 PARALLEL if the arg is to be copied into multiple non-contiguous
61 registers. */
62 rtx reg;
63 /* Register to pass this argument in when generating tail call sequence.
64 This is not the same register as for normal calls on machines with
65 register windows. */
66 rtx tail_call_reg;
67 /* If REG was promoted from the actual mode of the argument expression,
68 indicates whether the promotion is sign- or zero-extended. */
70 /* Number of registers to use. 0 means put the whole arg in registers.
71 Also 0 if not passed in registers. */
73 /* Nonzero if argument must be passed on stack.
74 Note that some arguments may be passed on the stack
75 even though pass_on_stack is zero, just because FUNCTION_ARG says so.
76 pass_on_stack identifies arguments that *cannot* go in registers. */
78 /* Some fields packaged up for locate_and_pad_parm. */
80 /* Location on the stack at which parameter should be stored. The store
81 has already been done if STACK == VALUE. */
82 rtx stack;
83 /* Location on the stack of the start of this argument slot. This can
84 differ from STACK if this arg pads downward. This location is known
85 to be aligned to FUNCTION_ARG_BOUNDARY. */
86 rtx stack_slot;
87 /* Place that this stack area has been saved, if needed. */
88 rtx save_area;
89 /* If an argument's alignment does not permit direct copying into registers,
90 copy in smaller-sized pieces into pseudos. These are stored in a
91 block pointed to by this field. The next field says how many
92 word-sized pseudos we made. */
95 };
97 /* A vector of one char per byte of stack space. A byte if nonzero if
98 the corresponding stack location has been used.
99 This vector is used to prevent a function call within an argument from
100 clobbering any stack already set up. */
103 /* Size of STACK_USAGE_MAP. */
106 /* A bitmap of virtual-incoming stack space. Bit is set if the corresponding
107 stack location's tail call argument has been already stored into the stack.
108 This bitmap is used to prevent sibling call optimization if function tries
109 to use parent's incoming argument slots when they have been already
110 overwritten with tail call arguments. */
113 /* stack_arg_under_construction is nonzero when an argument may be
114 initialized with a constructor call (including a C function that
115 returns a BLKmode struct) and expand_call must take special action
116 to make sure the object being constructed does not overlap the
117 argument list for the constructor call. */
122 CUMULATIVE_ARGS *);
149 #ifdef REG_PARM_STACK_SPACE
152 #endif
153 \f
154 /* Force FUNEXP into a form suitable for the address of a CALL,
155 and return that as an rtx. Also load the static chain register
156 if FNDECL is a nested function.
158 CALL_FUSAGE points to a variable holding the prospective
159 CALL_INSN_FUNCTION_USAGE information. */
161 rtx
164 {
165 /* Make a valid memory address and copy constants through pseudo-regs,
166 but not for a constant address if -fno-function-cse. */
168 /* If we are using registers for parameters, force the
169 function address into a register now. */
174 {
175 #ifndef NO_FUNCTION_CSE
178 #endif
179 }
182 {
188 }
191 }
193 /* Generate instructions to call function FUNEXP,
194 and optionally pop the results.
195 The CALL_INSN is the first insn generated.
197 FNDECL is the declaration node of the function. This is given to the
198 macro RETURN_POPS_ARGS to determine whether this function pops its own args.
200 FUNTYPE is the data type of the function. This is given to the macro
201 RETURN_POPS_ARGS to determine whether this function pops its own args.
202 We used to allow an identifier for library functions, but that doesn't
203 work when the return type is an aggregate type and the calling convention
204 says that the pointer to this aggregate is to be popped by the callee.
206 STACK_SIZE is the number of bytes of arguments on the stack,
207 ROUNDED_STACK_SIZE is that number rounded up to
208 PREFERRED_STACK_BOUNDARY; zero if the size is variable. This is
209 both to put into the call insn and to generate explicit popping
210 code if necessary.
212 STRUCT_VALUE_SIZE is the number of bytes wanted in a structure value.
213 It is zero if this call doesn't want a structure value.
215 NEXT_ARG_REG is the rtx that results from executing
216 FUNCTION_ARG (args_so_far, VOIDmode, void_type_node, 1)
217 just after all the args have had their registers assigned.
218 This could be whatever you like, but normally it is the first
219 arg-register beyond those used for args in this call,
220 or 0 if all the arg-registers are used in this call.
221 It is passed on to `gen_call' so you can put this info in the call insn.
223 VALREG is a hard register in which a value is returned,
224 or 0 if the call does not return a value.
226 OLD_INHIBIT_DEFER_POP is the value that `inhibit_defer_pop' had before
227 the args to this call were processed.
228 We restore `inhibit_defer_pop' to that value.
230 CALL_FUSAGE is either empty or an EXPR_LIST of USE expressions that
231 denote registers used by the called function. */
233 static void
235 tree funtype ATTRIBUTE_UNUSED,
236 HOST_WIDE_INT stack_size ATTRIBUTE_UNUSED,
237 HOST_WIDE_INT rounded_stack_size,
238 HOST_WIDE_INT struct_value_size ATTRIBUTE_UNUSED,
242 {
244 rtx call_insn;
247 #if defined (HAVE_call) && defined (HAVE_call_value)
248 rtx struct_value_size_rtx;
250 #endif
252 #ifdef CALL_POPS_ARGS
254 #endif
256 /* Ensure address is valid. SYMBOL_REF is already valid, so no need,
257 and we don't want to load it into a register as an optimization,
258 because prepare_call_address already did it if it should be done. */
262 #if defined (HAVE_sibcall_pop) && defined (HAVE_sibcall_value_pop)
266 {
268 rtx pat;
270 /* If this subroutine pops its own args, record that in the call insn
271 if possible, for the sake of frame pointer elimination. */
277 n_pop);
278 else
284 }
285 else
286 #endif
288 #if defined (HAVE_call_pop) && defined (HAVE_call_value_pop)
289 /* If the target has "call" or "call_value" insns, then prefer them
290 if no arguments are actually popped. If the target does not have
291 "call" or "call_value" insns, then we must use the popping versions
292 even if the call has no arguments to pop. */
293 #if defined (HAVE_call) && defined (HAVE_call_value)
296 #else
298 #endif
299 {
301 rtx pat;
303 /* If this subroutine pops its own args, record that in the call insn
304 if possible, for the sake of frame pointer elimination. */
310 else
316 }
317 else
318 #endif
320 #if defined (HAVE_sibcall) && defined (HAVE_sibcall_value)
323 {
327 rounded_stack_size_rtx,
329 else
332 struct_value_size_rtx));
333 }
334 else
335 #endif
337 #if defined (HAVE_call) && defined (HAVE_call_value)
339 {
344 NULL_RTX));
345 else
348 struct_value_size_rtx));
349 }
350 else
351 #endif
354 /* Find the call we just emitted. */
357 /* Mark memory as used for "pure" function call. */
359 call_fusage
360 = gen_rtx_EXPR_LIST
364 call_fusage);
366 /* Put the register usage information there. */
369 /* If this is a const call, then set the insn's unchanging bit. */
373 /* If this call can't throw, attach a REG_EH_REGION reg note to that
374 effect. */
378 else
379 {
382 /* If rn < 0, then either (1) tree-ssa not used or (2) doesn't
383 throw, which we already took care of. */
388 }
398 {
402 }
406 /* Restore this now, so that we do defer pops for this call's args
407 if the context of the call as a whole permits. */
411 {
420 }
423 {
424 /* If returning from the subroutine does not automatically pop the args,
425 we need an instruction to pop them sooner or later.
426 Perhaps do it now; perhaps just record how much space to pop later.
428 If returning from the subroutine does pop the args, indicate that the
429 stack pointer will be changed. */
432 {
434 /* Just pretend we did the pop. */
439 else
441 }
442 }
443 /* When we accumulate outgoing args, we must avoid any stack manipulations.
444 Restore the stack pointer to its original value now. Usually
445 ACCUMULATE_OUTGOING_ARGS targets don't get here, but there are exceptions.
446 On i386 ACCUMULATE_OUTGOING_ARGS can be enabled on demand, and
447 popping variants of functions exist as well.
449 ??? We may optimize similar to defer_pop above, but it is
450 probably not worthwhile.
452 ??? It will be worthwhile to enable combine_stack_adjustments even for
453 such machines. */
456 }
458 /* Determine if the function identified by NAME and FNDECL is one with
459 special properties we wish to know about.
461 For example, if the function might return more than one time (setjmp), then
462 set RETURNS_TWICE to a nonzero value.
464 Similarly set LONGJMP for if the function is in the longjmp family.
466 Set MAY_BE_ALLOCA for any memory allocation function that might allocate
467 space from the stack such as alloca. */
469 static int
471 {
474 /* Exclude functions not at the file scope, or not `extern',
475 since they are not the magic functions we would otherwise
476 think they are.
477 FIXME: this should be handled with attributes, not with this
478 hacky imitation of DECL_ASSEMBLER_NAME. It's (also) wrong
479 because you can declare fork() inside a function if you
480 wish. */
484 {
488 /* We assume that alloca will always be called by name. It
489 makes no sense to pass it as a pointer-to-function to
490 anything that does not understand its behavior. */
499 /* Disregard prefix _, __ or __x. */
501 {
506 else
508 }
511 {
524 }
534 }
537 }
539 /* Return nonzero when tree represent call to longjmp. */
541 int
543 {
545 }
547 /* Return true when exp contains alloca call. */
548 bool
550 {
559 }
561 /* Detect flags (function attributes) from the function decl or type node. */
563 int
565 {
570 {
575 {
580 }
582 /* The function exp may have the `malloc' attribute. */
586 /* The function exp may have the `pure' attribute. */
597 }
604 /* Mark if the function returns with the stack pointer depressed. We
605 cannot consider it pure or constant in that case. */
607 {
610 }
613 }
615 /* Detect flags from a CALL_EXPR. */
617 int
619 {
625 else
626 {
630 else
632 }
635 }
637 /* Precompute all register parameters as described by ARGS, storing values
638 into fields within the ARGS array.
640 NUM_ACTUALS indicates the total number elements in the ARGS array.
642 Set REG_PARM_SEEN if we encounter a register parameter. */
644 static void
646 {
653 {
657 {
663 }
665 /* If the value is a non-legitimate constant, force it into a
666 pseudo now. TLS symbols sometimes need a call to resolve. */
671 /* If we are to promote the function arg to a wider mode,
672 do it now. */
680 /* If the value is expensive, and we are inside an appropriately
681 short loop, put the value into a pseudo and then put the pseudo
682 into the hard reg.
684 For small register classes, also do this if this call uses
685 register parameters. This is to avoid reload conflicts while
686 loading the parameters registers. */
696 }
697 }
699 #ifdef REG_PARM_STACK_SPACE
701 /* The argument list is the property of the called routine and it
702 may clobber it. If the fixed area has been used for previous
703 parameters, we must save and restore it. */
705 static rtx
706 save_fixed_argument_area (int reg_parm_stack_space, rtx argblock, int *low_to_save, int *high_to_save)
707 {
711 /* Compute the boundary of the area that needs to be saved, if any. */
713 #ifdef ARGS_GROW_DOWNWARD
715 #endif
721 {
725 rtx stack_area;
726 rtx save_area;
729 ;
737 /* If we don't have the required alignment, must do this
738 in BLKmode. */
743 #ifdef ARGS_GROW_DOWNWARD
745 #else
747 #endif
751 delta)));
755 {
759 }
760 else
761 {
764 }
767 }
770 }
772 static void
774 {
777 rtx stack_area;
779 #ifdef ARGS_GROW_DOWNWARD
781 #else
783 #endif
791 else
794 BLOCK_OP_CALL_PARM);
795 }
798 /* If any elements in ARGS refer to parameters that are to be passed in
799 registers, but not in memory, and whose alignment does not permit a
800 direct copy into registers. Copy the values into a group of pseudos
801 which we will later copy into the appropriate hard registers.
803 Pseudos for each unaligned argument will be stored into the array
804 args[argnum].aligned_regs. The caller is responsible for deallocating
805 the aligned_regs array if it is nonzero. */
807 static void
809 {
817 {
825 /* Structures smaller than a word are normally aligned to the
826 least significant byte. On a BYTES_BIG_ENDIAN machine,
827 this means we must skip the empty high order bytes when
828 calculating the bit offset. */
830 #ifdef BLOCK_REG_PADDING
834 #else
835 && BYTES_BIG_ENDIAN
836 #endif
837 )
841 {
850 /* There is no need to restrict this code to loading items
851 in TYPE_ALIGN sized hunks. The bitfield instructions can
852 load up entire word sized registers efficiently.
854 ??? This may not be needed anymore.
855 We use to emit a clobber here but that doesn't let later
856 passes optimize the instructions we emit. By storing 0 into
857 the register later passes know the first AND to zero out the
858 bitfield being set in the register is unnecessary. The store
859 of 0 will be deleted as will at least the first AND. */
865 word);
866 }
867 }
868 }
870 /* Fill in ARGS_SIZE and ARGS array based on the parameters found in
871 ACTPARMS.
873 NUM_ACTUALS is the total number of parameters.
875 N_NAMED_ARGS is the total number of named arguments.
877 FNDECL is the tree code for the target of this call (if known)
879 ARGS_SO_FAR holds state needed by the target to know where to place
880 the next argument.
882 REG_PARM_STACK_SPACE is the number of bytes of stack space reserved
883 for arguments which are passed in registers.
885 OLD_STACK_LEVEL is a pointer to an rtx which olds the old stack level
886 and may be modified by this routine.
888 OLD_PENDING_ADJ, MUST_PREALLOCATE and FLAGS are pointers to integer
889 flags which may may be modified by this routine.
891 MAY_TAILCALL is cleared if we encounter an invisible pass-by-reference
892 that requires allocation of stack space.
894 CALL_FROM_THUNK_P is true if this call is the jump from a thunk to
895 the thunked-to function. */
897 static void
908 {
909 /* 1 if scanning parms front to back, -1 if scanning back to front. */
912 /* Count arg position in order args appear. */
916 tree p;
921 /* In this loop, we consider args in the order they are written.
922 We fill up ARGS from the front or from the back if necessary
923 so that in any case the first arg to be pushed ends up at the front. */
926 {
928 /* In this case, must reverse order of args
929 so that we compute and push the last arg first. */
930 }
931 else
932 {
934 }
936 /* I counts args in order (to be) pushed; ARGPOS counts in order written. */
938 {
945 /* Replace erroneous argument with constant zero. */
949 /* If TYPE is a transparent union, pass things the way we would
950 pass the first field of the union. We have already verified that
951 the modes are the same. */
955 /* Decide where to pass this arg.
957 args[i].reg is nonzero if all or part is passed in registers.
959 args[i].partial is nonzero if part but not all is passed in registers,
960 and the exact value says how many words are passed in registers.
962 args[i].pass_on_stack is nonzero if the argument must at least be
963 computed on the stack. It may then be loaded back into registers
964 if args[i].reg is nonzero.
966 These decisions are driven by the FUNCTION_... macros and must agree
967 with those made by function.c. */
969 /* See if this argument should be passed by invisible reference. */
972 {
973 /* If we're compiling a thunk, pass through invisible
974 references instead of making a copy. */
978 /* If it's in a register, we must make a copy of it too. */
979 /* ??? Is this a sufficient test? Is there a better one? */
983 )
984 {
985 /* C++ uses a TARGET_EXPR to indicate that we want to make a
986 new object from the argument. If we are passing by
987 invisible reference, the callee will do that for us, so we
988 can strip off the TARGET_EXPR. This is not always safe,
989 but it is safe in the only case where this is a useful
990 optimization; namely, when the argument is a plain object.
991 In that case, the frontend is just asking the backend to
992 make a bitwise copy of the argument. */
999 /* We can't use sibcalls if a callee-copied argument is stored
1000 in the current function's frame. */
1010 }
1012 {
1013 /* In the V3 C++ ABI, parameters are destroyed in the caller.
1014 We implement this by passing the address of the temporary
1015 rather than expanding it into another allocated slot. */
1021 }
1022 else
1023 {
1024 /* We make a copy of the object and pass the address to the
1025 function being called. */
1026 rtx copy;
1032 STACK_CHECK_MAX_VAR_SIZE))))
1033 {
1034 /* This is a variable-sized object. Make space on the stack
1035 for it. */
1039 {
1043 }
1046 allocate_dynamic_stack_space
1049 }
1050 else
1061 }
1062 }
1075 #ifdef FUNCTION_INCOMING_ARG
1076 /* If this is a sibling call and the machine has register windows, the
1077 register window has to be unwinded before calling the routine, so
1078 arguments have to go into the incoming registers. */
1081 #else
1083 #endif
1092 /* If FUNCTION_ARG returned a (parallel [(expr_list (nil) ...) ...]),
1093 it means that we are to pass this arg in the register(s) designated
1094 by the PARALLEL, but also to pass it in the stack. */
1099 /* If this is an addressable type, we must preallocate the stack
1100 since we must evaluate the object into its final location.
1102 If this is to be passed in both registers and the stack, it is simpler
1103 to preallocate. */
1108 /* If this is an addressable type, we cannot pre-evaluate it. Thus,
1109 we cannot consider this function call constant. */
1113 /* Compute the stack-size of this argument. */
1118 #ifdef STACK_PARMS_IN_REG_PARM_AREA
1120 #else
1122 #endif
1125 #ifdef BLOCK_REG_PADDING
1126 else
1127 /* The argument is passed entirely in registers. See at which
1128 end it should be padded. */
1132 #endif
1134 /* Update ARGS_SIZE, the total stack space for args so far. */
1140 /* Increment ARGS_SO_FAR, which has info about which arg-registers
1141 have been used, etc. */
1145 }
1146 }
1148 /* Update ARGS_SIZE to contain the total size for the argument block.
1149 Return the original constant component of the argument block's size.
1151 REG_PARM_STACK_SPACE holds the number of bytes of stack space reserved
1152 for arguments passed in registers. */
1154 static int
1158 {
1161 /* For accumulate outgoing args mode we don't need to align, since the frame
1162 will be already aligned. Align to STACK_BOUNDARY in order to prevent
1163 backends from generating misaligned frame sizes. */
1167 /* Compute the actual size of the argument block required. The variable
1168 and constant sizes must be combined, the size may have to be rounded,
1169 and there may be a minimum required size. */
1172 {
1178 {
1179 /* We don't handle this case yet. To handle it correctly we have
1180 to add the delta, round and subtract the delta.
1181 Currently no machine description requires this support. */
1185 }
1188 {
1189 args_size->var
1193 #ifndef OUTGOING_REG_PARM_STACK_SPACE
1194 /* The area corresponding to register parameters is not to count in
1195 the size of the block we need. So make the adjustment. */
1196 args_size->var
1199 #endif
1200 }
1201 }
1202 else
1203 {
1208 + stack_pointer_delta
1210 / preferred_stack_boundary
1215 reg_parm_stack_space);
1217 #ifndef OUTGOING_REG_PARM_STACK_SPACE
1219 #endif
1220 }
1222 }
1224 /* Precompute parameters as needed for a function call.
1226 FLAGS is mask of ECF_* constants.
1228 NUM_ACTUALS is the number of arguments.
1230 ARGS is an array containing information for each argument; this
1231 routine fills in the INITIAL_VALUE and VALUE fields for each
1232 precomputed argument. */
1234 static void
1236 {
1239 /* If this is a libcall, then precompute all arguments so that we do not
1240 get extraneous instructions emitted as part of the libcall sequence. */
1245 {
1248 /* If this is an addressable type, we cannot pre-evaluate it. */
1257 {
1261 #if defined(PROMOTE_FUNCTION_MODE) && !defined(PROMOTE_MODE)
1262 /* CSE will replace this only if it contains args[i].value
1263 pseudo, so convert it down to the declared mode using
1264 a SUBREG. */
1267 {
1273 }
1274 #endif
1275 }
1276 }
1277 }
1279 /* Given the current state of MUST_PREALLOCATE and information about
1280 arguments to a function call in NUM_ACTUALS, ARGS and ARGS_SIZE,
1281 compute and return the final value for MUST_PREALLOCATE. */
1283 static int
1284 finalize_must_preallocate (int must_preallocate, int num_actuals, struct arg_data *args, struct args_size *args_size)
1285 {
1286 /* See if we have or want to preallocate stack space.
1288 If we would have to push a partially-in-regs parm
1289 before other stack parms, preallocate stack space instead.
1291 If the size of some parm is not a multiple of the required stack
1292 alignment, we must preallocate.
1294 If the total size of arguments that would otherwise create a copy in
1295 a temporary (such as a CALL) is more than half the total argument list
1296 size, preallocation is faster.
1298 Another reason to preallocate is if we have a machine (like the m88k)
1299 where stack alignment is required to be maintained between every
1300 pair of insns, not just when the call is made. However, we assume here
1301 that such machines either do not have push insns (and hence preallocation
1302 would occur anyway) or the problem is taken care of with
1303 PUSH_ROUNDING. */
1306 {
1312 {
1323 copy_to_evaluate_size
1325 }
1330 }
1332 }
1334 /* If we preallocated stack space, compute the address of each argument
1335 and store it into the ARGS array.
1337 We need not ensure it is a valid memory address here; it will be
1338 validized when it is used.
1340 ARGBLOCK is an rtx for the address of the outgoing arguments. */
1342 static void
1344 {
1346 {
1354 {
1357 rtx addr;
1359 /* Skip this parm if it will not be passed on the stack. */
1365 else
1376 else
1385 /* Function incoming arguments may overlap with sibling call
1386 outgoing arguments and we cannot allow reordering of reads
1387 from function arguments with stores to outgoing arguments
1388 of sibling calls. */
1391 }
1392 }
1393 }
1395 /* Given a FNDECL and EXP, return an rtx suitable for use as a target address
1396 in a call instruction.
1398 FNDECL is the tree node for the target function. For an indirect call
1399 FNDECL will be NULL_TREE.
1401 ADDR is the operand 0 of CALL_EXPR for this call. */
1403 static rtx
1405 {
1406 rtx funexp;
1408 /* Get the function to call, in the form of RTL. */
1410 {
1411 /* If this is the first use of the function, see if we need to
1412 make an external definition for it. */
1414 {
1417 }
1419 /* Get a SYMBOL_REF rtx for the function address. */
1421 }
1422 else
1423 /* Generate an rtx (probably a pseudo-register) for the address. */
1424 {
1428 }
1430 }
1432 /* Do the register loads required for any wholly-register parms or any
1433 parms which are passed both on the stack and in a register. Their
1434 expressions were already evaluated.
1436 Mark all register-parms as living through the call, putting these USE
1437 insns in the CALL_INSN_FUNCTION_USAGE field.
1439 When IS_SIBCALL, perform the check_sibcall_overlap_argument_overlap
1440 checking, setting *SIBCALL_FAILURE if appropriate. */
1442 static void
1446 {
1450 {
1454 {
1459 /* Set to non-negative if must move a word at a time, even if just
1460 one word (e.g, partial == 1 && mode == DFmode). Set to -1 if
1461 we just use a normal move insn. This value can be zero if the
1462 argument is a zero size structure with no fields. */
1467 {
1470 }
1471 else
1474 /* Handle calls that pass values in multiple non-contiguous
1475 locations. The Irix 6 ABI has examples of this. */
1478 {
1482 }
1484 /* If simple case, just do move. If normal partial, store_one_arg
1485 has already loaded the register for us. In all other cases,
1486 load the register(s) from memory. */
1489 {
1491 #ifdef BLOCK_REG_PADDING
1492 /* Handle case where we have a value that needs shifting
1493 up to the msb. eg. a QImode value and we're padding
1494 upward on a BYTES_BIG_ENDIAN machine. */
1498 {
1499 rtx x;
1502 /* Assigning REG here rather than a temp makes CALL_FUSAGE
1503 report the whole reg as used. Strictly speaking, the
1504 call only uses SIZE bytes at the msb end, but it doesn't
1505 seem worth generating rtl to say that. */
1511 }
1512 #endif
1513 }
1515 /* If we have pre-computed the values to put in the registers in
1516 the case of non-aligned structures, copy them in now. */
1524 {
1527 /* Handle a BLKmode that needs shifting. */
1529 #ifdef BLOCK_REG_PADDING
1531 #else
1532 && BYTES_BIG_ENDIAN
1533 #endif
1534 )
1535 {
1548 }
1549 else
1551 }
1553 /* When a parameter is a block, and perhaps in other cases, it is
1554 possible that it did a load from an argument slot that was
1555 already clobbered. */
1560 /* Handle calls that pass values in multiple non-contiguous
1561 locations. The Irix 6 ABI has examples of this. */
1566 else
1568 }
1569 }
1570 }
1572 /* We need to pop PENDING_STACK_ADJUST bytes. But, if the arguments
1573 wouldn't fill up an even multiple of PREFERRED_UNIT_STACK_BOUNDARY
1574 bytes, then we would need to push some additional bytes to pad the
1575 arguments. So, we compute an adjust to the stack pointer for an
1576 amount that will leave the stack under-aligned by UNADJUSTED_ARGS_SIZE
1577 bytes. Then, when the arguments are pushed the stack will be perfectly
1578 aligned. ARGS_SIZE->CONSTANT is set to the number of bytes that should
1579 be popped after the call. Returns the adjustment. */
1581 static int
1585 {
1586 /* The number of bytes to pop so that the stack will be
1587 under-aligned by UNADJUSTED_ARGS_SIZE bytes. */
1588 HOST_WIDE_INT adjustment;
1589 /* The alignment of the stack after the arguments are pushed, if we
1590 just pushed the arguments without adjust the stack here. */
1593 unadjusted_alignment
1597 /* We want to get rid of as many of the PENDING_STACK_ADJUST bytes
1598 as possible -- leaving just enough left to cancel out the
1599 UNADJUSTED_ALIGNMENT. In other words, we want to ensure that the
1600 PENDING_STACK_ADJUST is non-negative, and congruent to
1601 -UNADJUSTED_ALIGNMENT modulo the PREFERRED_UNIT_STACK_BOUNDARY. */
1603 /* Begin by trying to pop all the bytes. */
1604 unadjusted_alignment
1605 = (unadjusted_alignment
1608 /* Push enough additional bytes that the stack will be aligned
1609 after the arguments are pushed. */
1611 {
1614 else
1616 }
1618 /* Now, sets ARGS_SIZE->CONSTANT so that we pop the right number of
1619 bytes after the call. The right number is the entire
1620 PENDING_STACK_ADJUST less our ADJUSTMENT plus the amount required
1621 by the arguments in the first place. */
1622 args_size->constant
1626 }
1628 /* Scan X expression if it does not dereference any argument slots
1629 we already clobbered by tail call arguments (as noted in stored_args_map
1630 bitmap).
1631 Return nonzero if X expression dereferences such argument slots,
1632 zero otherwise. */
1634 static int
1636 {
1637 RTX_CODE code;
1648 {
1653 current_function_internal_arg_pointer
1656 else
1659 #ifdef ARGS_GROW_DOWNWARD
1661 #endif
1669 }
1671 /* Scan all subexpressions. */
1674 {
1676 {
1679 }
1681 {
1685 }
1686 }
1688 }
1690 /* Scan sequence after INSN if it does not dereference any argument slots
1691 we already clobbered by tail call arguments (as noted in stored_args_map
1692 bitmap). If MARK_STORED_ARGS_MAP, add stack slots for ARG to
1693 stored_args_map bitmap afterwards (when ARG is a register MARK_STORED_ARGS_MAP
1694 should be 0). Return nonzero if sequence after INSN dereferences such argument
1695 slots, zero otherwise. */
1697 static int
1699 {
1704 else
1713 {
1714 #ifdef ARGS_GROW_DOWNWARD
1716 #else
1718 #endif
1722 }
1724 }
1726 /* If function value *VALUE was returned at the most significant end of a
1727 register, shift it towards the least significant end and convert it to
1728 TYPE's mode. Return true and update *VALUE if some action was needed.
1730 TYPE is the type of the function's return value, which is known not
1731 to have mode BLKmode. */
1733 static bool
1735 {
1737 {
1738 HOST_WIDE_INT shift;
1743 {
1744 /* Shift the value into the low part of the register. */
1748 /* Truncate it to the type's mode, or its integer equivalent.
1749 This is subject to TRULY_NOOP_TRUNCATION. */
1753 /* Now convert it to the final form. */
1756 }
1757 }
1759 }
1761 /* Remove all REG_EQUIV notes found in the insn chain. */
1763 static void
1765 {
1766 rtx insn;
1769 {
1771 {
1774 {
1775 /* Remove the note and keep looking at the notes for
1776 this insn. */
1779 }
1781 }
1782 }
1783 }
1785 /* Clear RTX_UNCHANGING_P flag of incoming argument MEMs. */
1787 static void
1789 {
1790 RTX_CODE code;
1800 {
1805 current_function_internal_arg_pointer
1809 }
1811 /* Scan all subexpressions. */
1814 {
1820 }
1821 }
1824 /* Generate all the code for a function call
1825 and return an rtx for its value.
1826 Store the value in TARGET (specified as an rtx) if convenient.
1827 If the value is stored in TARGET then TARGET is returned.
1828 If IGNORE is nonzero, then we ignore the value of the function call. */
1830 rtx
1832 {
1833 /* Nonzero if we are currently expanding a call. */
1836 /* List of actual parameters. */
1838 /* RTX for the function to be called. */
1839 rtx funexp;
1840 /* Sequence of insns to perform a normal "call". */
1842 /* Sequence of insns to perform a tail "call". */
1844 /* Data type of the function. */
1845 tree funtype;
1846 tree type_arg_types;
1847 /* Declaration of the function being called,
1848 or 0 if the function is computed (not known by name). */
1850 /* The type of the function being called. */
1851 tree fntype;
1855 /* Register in which non-BLKmode value will be returned,
1856 or 0 if no value or if value is BLKmode. */
1857 rtx valreg;
1858 /* Address where we should return a BLKmode value;
1859 0 if value not BLKmode. */
1861 /* Nonzero if that address is being passed by treating it as
1862 an extra, implicit first parameter. Otherwise,
1863 it is passed by being copied directly into struct_value_rtx. */
1865 /* Size of aggregate value wanted, or zero if none wanted
1866 or if we are using the non-reentrant PCC calling convention
1867 or expecting the value in registers. */
1869 /* Nonzero if called function returns an aggregate in memory PCC style,
1870 by returning the address of where to find it. */
1874 /* Number of actual parameters in this call, including struct value addr. */
1876 /* Number of named args. Args after this are anonymous ones
1877 and they must all go on the stack. */
1880 /* Vector of information about each argument.
1881 Arguments are numbered in the order they will be pushed,
1882 not the order they are written. */
1885 /* Total size in bytes of all the stack-parms scanned so far. */
1888 /* Size of arguments before any adjustments (such as rounding). */
1890 /* Data on reg parms scanned so far. */
1891 CUMULATIVE_ARGS args_so_far;
1892 /* Nonzero if a reg parm has been scanned. */
1894 /* Nonzero if this is an indirect function call. */
1896 /* Nonzero if we must avoid push-insns in the args for this call.
1897 If stack space is allocated for register parameters, but not by the
1898 caller, then it is preallocated in the fixed part of the stack frame.
1899 So the entire argument block must then be preallocated (i.e., we
1900 ignore PUSH_ROUNDING in that case). */
1904 /* Size of the stack reserved for parameter registers. */
1907 /* Address of space preallocated for stack parms
1908 (on machines that lack push insns), or 0 if space not preallocated. */
1911 /* Mask of ECF_ flags. */
1913 #ifdef REG_PARM_STACK_SPACE
1914 /* Define the boundary of the register parm stack space that needs to be
1915 saved, if any. */
1918 #endif
1925 /* State variables to track stack modifications. */
1931 /* Some stack pointer alterations we make are performed via
1932 allocate_dynamic_stack_space. This modifies the stack_pointer_delta,
1933 which we then also need to save/restore along the way. */
1936 rtx call_fusage;
1940 /* The alignment of the stack, in bits. */
1942 /* The alignment of the stack, in bytes. */
1944 /* The static chain value to use for this call. */
1945 rtx static_chain_value;
1946 /* See if this is "nothrow" function call. */
1950 /* See if we can find a DECL-node for the actual function, and get the
1951 function attributes (flags) from the function decl or type node. */
1954 {
1957 }
1958 else
1959 {
1962 }
1966 /* Warn if this value is an aggregate type,
1967 regardless of which calling convention we are using for it. */
1971 /* If the result of a pure or const function call is ignored (or void),
1972 and none of its arguments are volatile, we can avoid expanding the
1973 call and just evaluate the arguments for side-effects. */
1977 {
1979 tree arg;
1983 {
1986 }
1989 {
1994 }
1995 }
1997 #ifdef REG_PARM_STACK_SPACE
1999 #endif
2001 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2004 #endif
2006 /* Set up a place to return a structure. */
2008 /* Cater to broken compilers. */
2010 {
2011 /* This call returns a big structure. */
2014 #ifdef PCC_STATIC_STRUCT_RETURN
2015 {
2017 }
2019 {
2023 {
2024 /* The structure value address arg is already in actparms.
2025 Pull it out. It might be nice to just leave it there, but
2026 we need to set structure_value_addr. */
2031 }
2034 else
2035 {
2036 /* For variable-sized objects, we must be called with a target
2037 specified. If we were to allocate space on the stack here,
2038 we would have no way of knowing when to free it. */
2044 }
2045 }
2047 }
2049 /* Figure out the amount to which the stack should be aligned. */
2052 {
2056 }
2058 /* Operand 0 is a pointer-to-function; get the type of the function. */
2064 /* Munge the tree to split complex arguments into their imaginary
2065 and real parts. */
2067 {
2070 }
2071 else
2077 /* If struct_value_rtx is 0, it means pass the address
2078 as if it were an extra parameter. */
2080 {
2081 /* If structure_value_addr is a REG other than
2082 virtual_outgoing_args_rtx, we can use always use it. If it
2083 is not a REG, we must always copy it into a register.
2084 If it is virtual_outgoing_args_rtx, we must copy it to another
2085 register in some cases. */
2087 || (ACCUMULATE_OUTGOING_ARGS
2088 && stack_arg_under_construction
2094 actparms
2097 temp),
2098 actparms);
2100 }
2102 /* Count the arguments and set NUM_ACTUALS. */
2104 num_actuals++;
2106 /* Compute number of named args.
2107 First, do a raw count of the args for INIT_CUMULATIVE_ARGS. */
2110 n_named_args
2112 /* Count the struct value address, if it is passed as a parm. */
2114 else
2115 /* If we know nothing, treat all args as named. */
2118 /* Start updating where the next arg would go.
2120 On some machines (such as the PA) indirect calls have a different
2121 calling convention than normal calls. The fourth argument in
2122 INIT_CUMULATIVE_ARGS tells the backend if this is an indirect call
2123 or not. */
2126 /* Now possibly adjust the number of named args.
2127 Normally, don't include the last named arg if anonymous args follow.
2128 We do include the last named arg if
2129 targetm.calls.strict_argument_naming() returns nonzero.
2130 (If no anonymous args follow, the result of list_length is actually
2131 one too large. This is harmless.)
2133 If targetm.calls.pretend_outgoing_varargs_named() returns
2134 nonzero, and targetm.calls.strict_argument_naming() returns zero,
2135 this machine will be able to place unnamed args that were passed
2136 in registers into the stack. So treat all args as named. This
2137 allows the insns emitting for a specific argument list to be
2138 independent of the function declaration.
2140 If targetm.calls.pretend_outgoing_varargs_named() returns zero,
2141 we do not have any reliable way to pass unnamed args in
2142 registers, so we must force them into memory. */
2146 ;
2149 /* Don't include the last named arg. */
2151 else
2152 /* Treat all args as named. */
2155 /* Make a vector to hold all the information about each arg. */
2159 /* Build up entries in the ARGS array, compute the size of the
2160 arguments into ARGS_SIZE, etc. */
2169 {
2170 /* If this function requires a variable-sized argument list, don't
2171 try to make a cse'able block for this call. We may be able to
2172 do this eventually, but it is too complicated to keep track of
2173 what insns go in the cse'able block and which don't. */
2177 }
2179 /* Now make final decision about preallocating stack space. */
2184 /* If the structure value address will reference the stack pointer, we
2185 must stabilize it. We don't need to do this if we know that we are
2186 not going to adjust the stack pointer in processing this call. */
2191 structure_value_addr))
2196 /* Tail calls can make things harder to debug, and we've traditionally
2197 pushed these optimizations into -O2. Don't try if we're already
2198 expanding a call, as that means we're an argument. Don't try if
2199 there's cleanups, as we know there's code to follow the call. */
2202 || !flag_optimize_sibling_calls
2207 /* Rest of purposes for tail call optimizations to fail. */
2209 #ifdef HAVE_sibcall_epilogue
2210 !HAVE_sibcall_epilogue
2211 #else
2212 1
2213 #endif
2214 || !try_tail_call
2215 /* Doing sibling call optimization needs some work, since
2216 structure_value_addr can be allocated on the stack.
2217 It does not seem worth the effort since few optimizable
2218 sibling calls will return a structure. */
2220 /* Check whether the target is able to optimize the call
2221 into a sibcall. */
2223 /* Functions that do not return exactly once may not be sibcall
2224 optimized. */
2227 /* If the called function is nested in the current one, it might access
2228 some of the caller's arguments, but could clobber them beforehand if
2229 the argument areas are shared. */
2231 /* If this function requires more stack slots than the current
2232 function, we cannot change it into a sibling call. */
2234 /* If the callee pops its own arguments, then it must pop exactly
2235 the same number of arguments as the current function. */
2239 current_function_args_size))
2243 /* Ensure current function's preferred stack boundary is at least
2244 what we need. We don't have to increase alignment for recursive
2245 functions. */
2254 /* We want to make two insn chains; one for a sibling call, the other
2255 for a normal call. We will select one of the two chains after
2256 initial RTL generation is complete. */
2258 {
2260 /* We want to emit any pending stack adjustments before the tail
2261 recursion "call". That way we know any adjustment after the tail
2262 recursion call can be ignored if we indeed use the tail
2263 call expansion. */
2266 rtx insns;
2270 {
2271 /* State variables we need to save and restore between
2272 iterations. */
2275 }
2278 else
2281 /* Other state variables that we must reinitialize each time
2282 through the loop (that are not initialized by the loop itself). */
2286 /* Start a new sequence for the normal call case.
2288 From this point on, if the sibling call fails, we want to set
2289 sibcall_failure instead of continuing the loop. */
2292 /* Don't let pending stack adjusts add up to too much.
2293 Also, do all pending adjustments now if there is any chance
2294 this might be a call to alloca or if we are expanding a sibling
2295 call sequence or if we are calling a function that is to return
2296 with stack pointer depressed. */
2303 /* When calling a const function, we must pop the stack args right away,
2304 so that the pop is deleted or moved with the call. */
2306 NO_DEFER_POP;
2308 /* Precompute any arguments as needed. */
2312 /* Now we are about to start emitting insns that can be deleted
2313 if a libcall is deleted. */
2318 /* Compute the actual size of the argument block required. The variable
2319 and constant sizes must be combined, the size may have to be rounded,
2320 and there may be a minimum required size. When generating a sibcall
2321 pattern, do not round up, since we'll be re-using whatever space our
2322 caller provided. */
2323 unadjusted_args_size
2331 /* The argument block when performing a sibling call is the
2332 incoming argument block. */
2334 {
2336 argblock
2337 #ifdef STACK_GROWS_DOWNWARD
2339 #else
2341 #endif
2344 }
2346 /* If we have no actual push instructions, or shouldn't use them,
2347 make space for all args right now. */
2349 {
2351 {
2356 /* stack_arg_under_construction says whether a stack arg is
2357 being constructed at the old stack level. Pushing the stack
2358 gets a clean outgoing argument block. */
2361 }
2363 }
2364 else
2365 {
2366 /* Note that we must go through the motions of allocating an argument
2367 block even if the size is zero because we may be storing args
2368 in the area reserved for register arguments, which may be part of
2369 the stack frame. */
2373 /* Store the maximum argument space used. It will be pushed by
2374 the prologue (if ACCUMULATE_OUTGOING_ARGS, or stack overflow
2375 checking). */
2381 {
2383 {
2384 /* Since the stack pointer will never be pushed, it is
2385 possible for the evaluation of a parm to clobber
2386 something we have already written to the stack.
2387 Since most function calls on RISC machines do not use
2388 the stack, this is uncommon, but must work correctly.
2390 Therefore, we save any area of the stack that was already
2391 written and that we are using. Here we set up to do this
2392 by making a new stack usage map from the old one. The
2393 actual save will be done by store_one_arg.
2395 Another approach might be to try to reorder the argument
2396 evaluations to avoid this conflicting stack usage. */
2398 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2399 /* Since we will be writing into the entire argument area,
2400 the map must be allocated for its entire size, not just
2401 the part that is the responsibility of the caller. */
2403 #endif
2405 #ifdef ARGS_GROW_DOWNWARD
2408 #else
2410 needed);
2411 #endif
2416 initial_highest_arg_in_use);
2420 (highest_outgoing_arg_in_use
2424 /* The address of the outgoing argument list must not be
2425 copied to a register here, because argblock would be left
2426 pointing to the wrong place after the call to
2427 allocate_dynamic_stack_space below. */
2430 }
2431 else
2432 {
2434 {
2435 /* Try to reuse some or all of the pending_stack_adjust
2436 to get this space. */
2437 needed
2438 = (combine_pending_stack_adjustment_and_call
2441 preferred_unit_stack_boundary));
2443 /* combine_pending_stack_adjustment_and_call computes
2444 an adjustment before the arguments are allocated.
2445 Account for them and see whether or not the stack
2446 needs to go up or down. */
2450 {
2451 /* We're releasing stack space. */
2452 /* ??? We can avoid any adjustment at all if we're
2453 already aligned. FIXME. */
2457 }
2458 else
2459 /* We need to allocate space. We'll do that in
2460 push_block below. */
2462 }
2464 /* Special case this because overhead of `push_block' in
2465 this case is non-trivial. */
2468 else
2469 {
2471 #ifdef ARGS_GROW_DOWNWARD
2473 #endif
2474 }
2476 /* We only really need to call `copy_to_reg' in the case
2477 where push insns are going to be used to pass ARGBLOCK
2478 to a function call in ARGS. In that case, the stack
2479 pointer changes value from the allocation point to the
2480 call point, and hence the value of
2481 VIRTUAL_OUTGOING_ARGS_RTX changes as well. But might
2482 as well always do it. */
2484 }
2485 }
2486 }
2489 {
2490 /* The save/restore code in store_one_arg handles all
2491 cases except one: a constructor call (including a C
2492 function returning a BLKmode struct) to initialize
2493 an argument. */
2495 {
2496 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2499 #else
2501 #endif
2503 {
2505 NULL_RTX);
2509 /* stack_arg_under_construction says whether a stack
2510 arg is being constructed at the old stack level.
2511 Pushing the stack gets a clean outgoing argument
2512 block. */
2513 old_stack_arg_under_construction
2516 /* Make a new map for the new argument list. */
2520 }
2522 BITS_PER_UNIT);
2523 }
2525 /* If argument evaluation might modify the stack pointer,
2526 copy the address of the argument list to a register. */
2529 {
2532 }
2533 }
2537 /* If we push args individually in reverse order, perform stack alignment
2538 before the first push (the last arg). */
2541 {
2542 /* When the stack adjustment is pending, we get better code
2543 by combining the adjustments. */
2547 {
2548 pending_stack_adjust
2549 = (combine_pending_stack_adjustment_and_call
2552 preferred_unit_stack_boundary));
2554 }
2558 }
2559 /* Now that the stack is properly aligned, pops can't safely
2560 be deferred during the evaluation of the arguments. */
2561 NO_DEFER_POP;
2565 /* Figure out the register where the value, if any, will come back. */
2569 {
2573 else
2575 }
2577 /* Precompute all register parameters. It isn't safe to compute anything
2578 once we have started filling any specific hard regs. */
2584 else
2587 #ifdef REG_PARM_STACK_SPACE
2588 /* Save the fixed argument area if it's part of the caller's frame and
2589 is clobbered by argument setup for this call. */
2593 #endif
2595 /* Now store (and compute if necessary) all non-register parms.
2596 These come before register parms, since they can require block-moves,
2597 which could clobber the registers used for register parms.
2598 Parms which have partial registers are not stored here,
2599 but we do preallocate space here if they want that. */
2603 {
2608 reg_parm_stack_space)
2620 call_fusage);
2621 }
2623 /* If we have a parm that is passed in registers but not in memory
2624 and whose alignment does not permit a direct copy into registers,
2625 make a group of pseudos that correspond to each register that we
2626 will later fill. */
2630 /* Now store any partially-in-registers parm.
2631 This is the last place a block-move can happen. */
2635 {
2640 reg_parm_stack_space)
2645 }
2647 /* If we pushed args in forward order, perform stack alignment
2648 after pushing the last arg. */
2653 /* If register arguments require space on the stack and stack space
2654 was not preallocated, allocate stack space here for arguments
2655 passed in registers. */
2656 #ifdef OUTGOING_REG_PARM_STACK_SPACE
2660 #endif
2662 /* Pass the function the address in which to return a
2663 structure value. */
2665 {
2666 structure_value_addr
2671 NULL_RTX)));
2675 }
2683 /* Save a pointer to the last insn before the call, so that we can
2684 later safely search backwards to find the CALL_INSN. */
2687 /* Set up next argument register. For sibling calls on machines
2688 with register windows this should be the incoming register. */
2689 #ifdef FUNCTION_INCOMING_ARG
2693 else
2694 #endif
2698 /* All arguments and registers used for the call must be set up by
2699 now! */
2701 /* Stack must be properly aligned now. */
2705 /* Generate the actual call instruction. */
2711 /* If call is cse'able, make appropriate pair of reg-notes around it.
2712 Test valreg so we don't crash; may safely ignore `const'
2713 if return type is void. Disable for PARALLEL return values, because
2714 we have no way to move such values into a pseudo register. */
2716 {
2717 rtx insns;
2718 rtx insn;
2723 /* Expansion of block moves possibly introduced a loop that may
2724 not appear inside libcall block. */
2730 {
2733 }
2734 else
2735 {
2739 /* Mark the return value as a pointer if needed. */
2746 && fndecl
2754 else
2755 {
2756 /* Construct an "equal form" for the value which
2757 mentions all the arguments in order as well as
2758 the function name. */
2769 note);
2770 }
2774 }
2775 }
2777 {
2781 /* The return value from a malloc-like function is a pointer. */
2787 /* The return value from a malloc-like function can not alias
2788 anything else. */
2793 /* Write out the sequence. */
2798 }
2800 /* For calls to `setjmp', etc., inform flow.c it should complain
2801 if nonvolatile values are live. For functions that cannot return,
2802 inform flow that control does not fall through. */
2805 {
2806 /* The barrier must be emitted
2807 immediately after the CALL_INSN. Some ports emit more
2808 than just a CALL_INSN above, so we must search for it here. */
2812 {
2814 /* There was no CALL_INSN? */
2817 }
2821 /* Stack adjustments after a noreturn call are dead code.
2822 However when NO_DEFER_POP is in effect, we must preserve
2823 stack_pointer_delta. */
2825 {
2828 }
2829 }
2834 /* If value type not void, return an rtx for the value. */
2840 {
2842 {
2843 target
2846 structure_value_addr));
2848 }
2849 }
2851 {
2852 /* This is the special C++ case where we need to
2853 know what the true target was. We take care to
2854 never use this value more than once in one expression. */
2858 }
2859 /* Handle calls that return values in multiple non-contiguous locations.
2860 The Irix 6 ABI has examples of this. */
2862 {
2864 {
2865 /* This will only be assigned once, so it can be readonly. */
2872 }
2878 /* We can not support sibling calls for this case. */
2880 }
2884 {
2885 /* TARGET and VALREG cannot be equal at this point because the
2886 latter would not have REG_FUNCTION_VALUE_P true, while the
2887 former would if it were referring to the same register.
2889 If they refer to the same register, this move will be a no-op,
2890 except when function inlining is being done. */
2893 /* If we are setting a MEM, this code must be executed. Since it is
2894 emitted after the call insn, sibcall optimization cannot be
2895 performed in that case. */
2898 }
2900 {
2903 /* We can not support sibling calls for this case. */
2905 }
2906 else
2907 {
2912 }
2915 {
2916 /* If we promoted this return value, make the proper SUBREG. TARGET
2917 might be const0_rtx here, so be careful. */
2921 {
2926 /* If we don't promote as expected, something is wrong. */
2934 {
2941 }
2945 }
2946 }
2948 /* If size of args is variable or this was a constructor call for a stack
2949 argument, restore saved stack-pointer value. */
2952 {
2961 }
2963 {
2964 #ifdef REG_PARM_STACK_SPACE
2968 #endif
2970 /* If we saved any argument areas, restore them. */
2973 {
2975 rtx stack_area
2982 else
2985 BLOCK_OP_CALL_PARM);
2986 }
2990 }
2992 /* If this was alloca, record the new stack level for nonlocal gotos.
2993 Check for the handler slots since we might not have a save area
2994 for non-local gotos. */
2999 /* Free up storage we no longer need. */
3004 /* If this function is returning into a memory location marked as
3005 readonly, it means it is initializing that location. We normally treat
3006 functions as not clobbering such locations, so we need to specify that
3007 this one does. We do this by adding the appropriate CLOBBER to the
3008 CALL_INSN function usage list. This cannot be done by emitting a
3009 standalone CLOBBER after the call because the latter would be ignored
3010 by at least the delay slot scheduling pass. We do this now instead of
3011 adding to call_fusage before the call to emit_call_1 because TARGET
3012 may be modified in the meantime. */
3015 add_function_usage_to
3018 NULL_RTX));
3024 {
3027 /* Restore the pending stack adjustment now that we have
3028 finished generating the sibling call sequence. */
3033 /* Prepare arg structure for next iteration. */
3035 {
3039 }
3042 }
3043 else
3044 {
3047 /* Verify that we've deallocated all the stack we used. */
3052 }
3054 /* If something prevents making this a sibling call,
3055 zero out the sequence. */
3058 else
3060 }
3062 /* If tail call production succeeded, we need to remove REG_EQUIV notes on
3063 arguments too, as argument area is now clobbered by the call. */
3065 {
3068 }
3069 else
3072 currently_expanding_call--;
3074 /* If this function returns with the stack pointer depressed, ensure
3075 this block saves and restores the stack pointer, show it was
3076 changed, and adjust for any outgoing arg space. */
3078 {
3082 }
3085 }
3087 /* A sibling call sequence invalidates any REG_EQUIV notes made for
3088 this function's incoming arguments.
3090 At the start of RTL generation we know the only REG_EQUIV notes
3091 in the rtl chain are those for incoming arguments, so we can safely
3092 flush any REG_EQUIV note.
3094 This is (slight) overkill. We could keep track of the highest
3095 argument we clobber and be more selective in removing notes, but it
3096 does not seem to be worth the effort. */
3097 void
3099 {
3100 rtx insn;
3101 tree arg;
3105 /* A sibling call sequence also may invalidate RTX_UNCHANGING_P
3106 flag of some incoming arguments MEM RTLs, because it can write into
3107 those slots. We clear all those bits now.
3109 This is (slight) overkill, we could keep track of which arguments
3110 we actually write into. */
3112 {
3115 }
3117 /* Similarly, invalidate RTX_UNCHANGING_P for any incoming
3118 arguments passed in registers. */
3120 arg;
3122 {
3125 }
3126 }
3128 /* Traverse an argument list in VALUES and expand all complex
3129 arguments into their components. */
3130 tree
3132 {
3133 tree p;
3135 /* Before allocating memory, check for the common case of no complex. */
3137 {
3142 }
3145 found:
3149 {
3151 tree complex_type;
3159 {
3160 tree subtype;
3174 /* Skip the newly created node. */
3176 }
3177 }
3180 }
3182 /* Traverse a list of TYPES and expand all complex types into their
3183 components. */
3184 tree
3186 {
3187 tree p;
3189 /* Before allocating memory, check for the common case of no complex. */
3191 {
3196 }
3199 found:
3203 {
3208 {
3211 /* Rewrite complex type with component type. */
3215 /* Add another component type for the imaginary part. */
3220 /* Skip the newly created node. */
3222 }
3223 }
3226 }
3227 \f
3228 /* Output a library call to function FUN (a SYMBOL_REF rtx).
3229 The RETVAL parameter specifies whether return value needs to be saved, other
3230 parameters are documented in the emit_library_call function below. */
3232 static rtx
3236 {
3237 /* Total size in bytes of all the stack-parms scanned so far. */
3239 /* Size of arguments before any adjustments (such as rounding). */
3242 rtx fun;
3246 CUMULATIVE_ARGS args_so_far;
3247 struct arg
3248 {
3249 rtx value;
3251 rtx reg;
3254 rtx save_area;
3255 };
3260 rtx valreg;
3266 rtx before_call;
3269 #ifdef REG_PARM_STACK_SPACE
3270 /* Define the boundary of the register parm stack space that needs to be
3271 save, if any. */
3274 #endif
3276 /* Size of the stack reserved for parameter registers. */
3282 #ifdef REG_PARM_STACK_SPACE
3284 #endif
3286 /* By default, library functions can not throw. */
3290 {
3317 }
3320 /* Ensure current function's preferred stack boundary is at least
3321 what we need. */
3325 /* If this kind of value comes back in memory,
3326 decide where in memory it should come back. */
3328 {
3331 {
3332 #ifdef PCC_STATIC_STRUCT_RETURN
3333 rtx pointer_reg
3343 else
3345 #endif
3346 /* This call returns a big structure. */
3348 }
3349 }
3350 else
3353 /* ??? Unfinished: must pass the memory address as an argument. */
3355 /* Copy all the libcall-arguments out of the varargs data
3356 and into a vector ARGVEC.
3358 Compute how to pass each argument. We only support a very small subset
3359 of the full argument passing conventions to limit complexity here since
3360 library functions shouldn't have many args. */
3365 #ifdef INIT_CUMULATIVE_LIBCALL_ARGS
3367 #else
3369 #endif
3376 /* Now we are about to start emitting insns that can be deleted
3377 if a libcall is deleted. */
3383 /* If there's a structure value address to be passed,
3384 either pass it in the special place, or pass it as an extra argument. */
3386 {
3388 nargs++;
3390 /* Make sure it is a reasonable operand for a move or push insn. */
3404 #ifdef STACK_PARMS_IN_REG_PARM_AREA
3406 #else
3408 #endif
3417 count++;
3418 }
3421 {
3425 /* We cannot convert the arg value to the mode the library wants here;
3426 must do it earlier where we know the signedness of the arg. */
3431 /* Make sure it is a reasonable operand for a move or push insn. */
3437 {
3438 rtx slot;
3442 /* loop.c won't look at CALL_INSN_FUNCTION_USAGE of const/pure
3443 functions, so we have to pretend this isn't such a function. */
3445 {
3449 }
3452 /* If this was a CONST function, it is now PURE since
3453 it now reads memory. */
3455 {
3458 }
3463 {
3467 }
3468 else
3469 {
3472 slot
3478 }
3482 call_fusage);
3486 slot),
3487 call_fusage);
3491 }
3502 #ifdef STACK_PARMS_IN_REG_PARM_AREA
3504 #else
3506 #endif
3518 }
3520 /* If this machine requires an external definition for library
3521 functions, write one out. */
3526 + stack_pointer_delta
3528 / STACK_BYTES
3533 reg_parm_stack_space);
3535 #ifndef OUTGOING_REG_PARM_STACK_SPACE
3537 #endif
3543 {
3544 /* Since the stack pointer will never be pushed, it is possible for
3545 the evaluation of a parm to clobber something we have already
3546 written to the stack. Since most function calls on RISC machines
3547 do not use the stack, this is uncommon, but must work correctly.
3549 Therefore, we save any area of the stack that was already written
3550 and that we are using. Here we set up to do this by making a new
3551 stack usage map from the old one.
3553 Another approach might be to try to reorder the argument
3554 evaluations to avoid this conflicting stack usage. */
3558 #ifndef OUTGOING_REG_PARM_STACK_SPACE
3559 /* Since we will be writing into the entire argument area, the
3560 map must be allocated for its entire size, not just the part that
3561 is the responsibility of the caller. */
3563 #endif
3565 #ifdef ARGS_GROW_DOWNWARD
3568 #else
3570 needed);
3571 #endif
3576 initial_highest_arg_in_use);
3583 /* We must be careful to use virtual regs before they're instantiated,
3584 and real regs afterwards. Loop optimization, for example, can create
3585 new libcalls after we've instantiated the virtual regs, and if we
3586 use virtuals anyway, they won't match the rtl patterns. */
3590 else
3592 }
3593 else
3594 {
3597 }
3599 /* If we push args individually in reverse order, perform stack alignment
3600 before the first push (the last arg). */
3606 {
3609 }
3610 else
3611 {
3614 }
3616 #ifdef REG_PARM_STACK_SPACE
3618 {
3619 /* The argument list is the property of the called routine and it
3620 may clobber it. If the fixed area has been used for previous
3621 parameters, we must save and restore it. */
3624 }
3625 #endif
3627 /* Push the args that need to be pushed. */
3629 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
3630 are to be pushed. */
3632 {
3640 {
3642 {
3643 /* If this is being stored into a pre-allocated, fixed-size,
3644 stack area, save any previous data at that location. */
3646 #ifdef ARGS_GROW_DOWNWARD
3647 /* stack_slot is negative, but we want to index stack_usage_map
3648 with positive values. */
3651 #else
3654 #endif
3657 /* Don't worry about things in the fixed argument area;
3658 it has already been saved. */
3662 i++;
3665 {
3666 /* We need to make a save area. */
3667 unsigned int size
3669 enum machine_mode save_mode
3671 rtx adr
3674 rtx stack_area
3678 {
3685 stack_area,
3687 BLOCK_OP_CALL_PARM);
3688 }
3689 else
3690 {
3694 }
3695 }
3696 }
3701 reg_parm_stack_space,
3704 /* Now mark the segment we just used. */
3709 NO_DEFER_POP;
3710 }
3711 }
3713 /* If we pushed args in forward order, perform stack alignment
3714 after pushing the last arg. */
3721 else
3726 /* Now load any reg parms into their regs. */
3728 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
3729 are to be pushed. */
3731 {
3737 /* Handle calls that pass values in multiple non-contiguous
3738 locations. The PA64 has examples of this for library calls. */
3744 NO_DEFER_POP;
3745 }
3747 /* Any regs containing parms remain in use through the call. */
3749 {
3755 }
3757 /* Pass the function the address in which to return a structure value. */
3759 {
3763 NULL_RTX)));
3766 }
3768 /* Don't allow popping to be deferred, since then
3769 cse'ing of library calls could delete a call and leave the pop. */
3770 NO_DEFER_POP;
3774 /* Stack must be properly aligned now. */
3780 /* We pass the old value of inhibit_defer_pop + 1 to emit_call_1, which
3781 will set inhibit_defer_pop to that value. */
3782 /* The return type is needed to decide how many bytes the function pops.
3783 Signedness plays no role in that, so for simplicity, we pretend it's
3784 always signed. We also assume that the list of arguments passed has
3785 no impact, so we pretend it is unknown. */
3791 struct_value_size,
3793 valreg,
3796 /* For calls to `setjmp', etc., inform flow.c it should complain
3797 if nonvolatile values are live. For functions that cannot return,
3798 inform flow that control does not fall through. */
3801 {
3802 /* The barrier note must be emitted
3803 immediately after the CALL_INSN. Some ports emit more than
3804 just a CALL_INSN above, so we must search for it here. */
3808 {
3810 /* There was no CALL_INSN? */
3813 }
3816 }
3818 /* Now restore inhibit_defer_pop to its actual original value. */
3819 OK_DEFER_POP;
3821 /* If call is cse'able, make appropriate pair of reg-notes around it.
3822 Test valreg so we don't crash; may safely ignore `const'
3823 if return type is void. Disable for PARALLEL return values, because
3824 we have no way to move such values into a pseudo register. */
3826 {
3827 rtx insns;
3830 {
3834 }
3835 else
3836 {
3838 rtx temp;
3842 {
3847 }
3851 /* Construct an "equal form" for the value which mentions all the
3852 arguments in order as well as the function name. */
3865 note);
3870 }
3871 }
3874 /* Copy the value to the right place. */
3876 {
3878 {
3883 }
3885 {
3889 }
3892 else
3894 }
3897 {
3898 #ifdef REG_PARM_STACK_SPACE
3902 #endif
3904 /* If we saved any argument areas, restore them. */
3907 {
3918 BLOCK_OP_CALL_PARM);
3919 else
3921 }
3925 }
3929 }
3930 \f
3931 /* Output a library call to function FUN (a SYMBOL_REF rtx)
3932 (emitting the queue unless NO_QUEUE is nonzero),
3933 for a value of mode OUTMODE,
3934 with NARGS different arguments, passed as alternating rtx values
3935 and machine_modes to convert them to.
3937 FN_TYPE should be LCT_NORMAL for `normal' calls, LCT_CONST for `const'
3938 calls, LCT_PURE for `pure' calls, LCT_CONST_MAKE_BLOCK for `const' calls
3939 which should be enclosed in REG_LIBCALL/REG_RETVAL notes,
3940 LCT_PURE_MAKE_BLOCK for `purep' calls which should be enclosed in
3941 REG_LIBCALL/REG_RETVAL notes with extra (use (memory (scratch)),
3942 or other LCT_ value for other types of library calls. */
3944 void
3947 {
3953 }
3954 \f
3955 /* Like emit_library_call except that an extra argument, VALUE,
3956 comes second and says where to store the result.
3957 (If VALUE is zero, this function chooses a convenient way
3958 to return the value.
3960 This function returns an rtx for where the value is to be found.
3961 If VALUE is nonzero, VALUE is returned. */
3963 rtx
3967 {
3968 rtx result;
3977 }
3978 \f
3979 /* Store a single argument for a function call
3980 into the register or memory area where it must be passed.
3981 *ARG describes the argument value and where to pass it.
3983 ARGBLOCK is the address of the stack-block for all the arguments,
3984 or 0 on a machine where arguments are pushed individually.
3986 MAY_BE_ALLOCA nonzero says this could be a call to `alloca'
3987 so must be careful about how the stack is used.
3989 VARIABLE_SIZE nonzero says that this was a variable-sized outgoing
3990 argument stack. This is used if ACCUMULATE_OUTGOING_ARGS to indicate
3991 that we need not worry about saving and restoring the stack.
3993 FNDECL is the declaration of the function we are calling.
3995 Return nonzero if this arg should cause sibcall failure,
3996 zero otherwise. */
3998 static int
4001 {
4012 /* Push a new temporary level for any temporaries we make for
4013 this argument. */
4017 {
4018 /* If this is being stored into a pre-allocated, fixed-size, stack area,
4019 save any previous data at that location. */
4021 {
4022 #ifdef ARGS_GROW_DOWNWARD
4023 /* stack_slot is negative, but we want to index stack_usage_map
4024 with positive values. */
4027 else
4031 #else
4034 else
4038 #endif
4041 /* Don't worry about things in the fixed argument area;
4042 it has already been saved. */
4046 i++;
4049 {
4050 /* We need to make a save area. */
4057 {
4066 BLOCK_OP_CALL_PARM);
4067 }
4068 else
4069 {
4072 }
4073 }
4074 }
4075 }
4077 /* If this isn't going to be placed on both the stack and in registers,
4078 set up the register and number of words. */
4080 {
4083 else
4086 }
4089 /* Being passed entirely in a register. We shouldn't be called in
4090 this case. */
4093 /* If this arg needs special alignment, don't load the registers
4094 here. */
4098 /* If this is being passed partially in a register, we can't evaluate
4099 it directly into its stack slot. Otherwise, we can. */
4101 {
4102 /* stack_arg_under_construction is nonzero if a function argument is
4103 being evaluated directly into the outgoing argument list and
4104 expand_call must take special action to preserve the argument list
4105 if it is called recursively.
4107 For scalar function arguments stack_usage_map is sufficient to
4108 determine which stack slots must be saved and restored. Scalar
4109 arguments in general have pass_on_stack == 0.
4111 If this argument is initialized by a function which takes the
4112 address of the argument (a C++ constructor or a C function
4113 returning a BLKmode structure), then stack_usage_map is
4114 insufficient and expand_call must push the stack around the
4115 function call. Such arguments have pass_on_stack == 1.
4117 Note that it is always safe to set stack_arg_under_construction,
4118 but this generates suboptimal code if set when not needed. */
4121 stack_arg_under_construction++;
4124 (partial
4129 /* If we are promoting object (or for any other reason) the mode
4130 doesn't agree, convert the mode. */
4137 stack_arg_under_construction--;
4138 }
4140 /* Don't allow anything left on stack from computation
4141 of argument to alloca. */
4146 /* If the value is already in the stack slot, we are done. */
4147 ;
4149 {
4152 /* Argument is a scalar, not entirely passed in registers.
4153 (If part is passed in registers, arg->partial says how much
4154 and emit_push_insn will take care of putting it there.)
4156 Push it, and if its size is less than the
4157 amount of space allocated to it,
4158 also bump stack pointer by the additional space.
4159 Note that in C the default argument promotions
4160 will prevent such mismatches. */
4163 /* Compute how much space the push instruction will push.
4164 On many machines, pushing a byte will advance the stack
4165 pointer by a halfword. */
4166 #ifdef PUSH_ROUNDING
4168 #endif
4171 /* Compute how much space the argument should get:
4172 round up to a multiple of the alignment for arguments. */
4178 /* This isn't already where we want it on the stack, so put it there.
4179 This can either be done with push or copy insns. */
4185 /* Unless this is a partially-in-register argument, the argument is now
4186 in the stack. */
4189 }
4190 else
4191 {
4192 /* BLKmode, at least partly to be pushed. */
4196 rtx size_rtx;
4198 /* Pushing a nonscalar.
4199 If part is passed in registers, PARTIAL says how much
4200 and emit_push_insn will take care of putting it there. */
4202 /* Round its size up to a multiple
4203 of the allocation unit for arguments. */
4206 {
4209 }
4210 else
4211 {
4212 /* PUSH_ROUNDING has no effect on us, because
4213 emit_push_insn for BLKmode is careful to avoid it. */
4215 {
4216 /* Use the size of the elt to compute excess. */
4221 }
4222 else
4228 }
4230 /* Some types will require stricter alignment, which will be
4231 provided for elsewhere in argument layout. */
4234 /* When an argument is padded down, the block is aligned to
4235 PARM_BOUNDARY, but the actual argument isn't. */
4237 {
4241 {
4244 }
4245 }
4248 {
4249 /* emit_push_insn might not work properly if arg->value and
4250 argblock + arg->locate.offset areas overlap. */
4257 current_function_internal_arg_pointer
4259 {
4263 /* expand_call should ensure this. */
4268 {
4271 }
4273 {
4276 }
4277 }
4278 }
4285 /* Unless this is a partially-in-register argument, the argument is now
4286 in the stack.
4288 ??? Unlike the case above, in which we want the actual
4289 address of the data, so that we can load it directly into a
4290 register, here we want the address of the stack slot, so that
4291 it's properly aligned for word-by-word copying or something
4292 like that. It's not clear that this is always correct. */
4295 }
4297 /* Mark all slots this store used. */
4303 /* Once we have pushed something, pops can't safely
4304 be deferred during the rest of the arguments. */
4305 NO_DEFER_POP;
4307 /* Free any temporary slots made in processing this argument. Show
4308 that we might have taken the address of something and pushed that
4309 as an operand. */
4315 }
4317 /* Nonzero if we do not know how to pass TYPE solely in registers. */
4319 bool
4321 tree type)
4322 {
4326 /* If the type has variable size... */
4330 /* If the type is marked as addressable (it is required
4331 to be constructed into the stack)... */
4336 }
4338 /* Another version of the TARGET_MUST_PASS_IN_STACK hook. This one
4339 takes trailing padding of a structure into account. */
4340 /* ??? Should be able to merge these two by examining BLOCK_REG_PADDING. */
4342 bool
4344 {
4348 /* If the type has variable size... */
4352 /* If the type is marked as addressable (it is required
4353 to be constructed into the stack)... */
4357 /* If the padding and mode of the type is such that a copy into
4358 a register would put it into the wrong part of the register. */
4366 }