| blob | d1fcdadda33eef1fdca48e3eeaed982b2f4a70db |
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, 51 Franklin Street, Fifth Floor, Boston, MA
21 02110-1301, 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 bytes to put in registers. 0 means put the whole arg
75 in registers. 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 NORETURN 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 }
538 }
541 }
543 /* Return nonzero when FNDECL represents a call to setjmp. */
545 int
547 {
549 }
551 /* Return true when exp contains alloca call. */
552 bool
554 {
563 }
565 /* Detect flags (function attributes) from the function decl or type node. */
567 int
569 {
574 {
577 /* The function exp may have the `malloc' attribute. */
581 /* The function exp may have the `returns_twice' attribute. */
585 /* The function exp may have the `pure' attribute. */
599 }
606 /* Mark if the function returns with the stack pointer depressed. We
607 cannot consider it pure or constant in that case. */
609 {
612 }
615 }
617 /* Detect flags from a CALL_EXPR. */
619 int
621 {
627 else
628 {
632 else
634 }
637 }
639 /* Precompute all register parameters as described by ARGS, storing values
640 into fields within the ARGS array.
642 NUM_ACTUALS indicates the total number elements in the ARGS array.
644 Set REG_PARM_SEEN if we encounter a register parameter. */
646 static void
649 {
656 {
660 {
665 }
667 /* If the value is a non-legitimate constant, force it into a
668 pseudo now. TLS symbols sometimes need a call to resolve. */
673 /* If we are to promote the function arg to a wider mode,
674 do it now. */
682 /* If we're going to have to load the value by parts, pull the
683 parts into pseudos. The part extraction process can involve
684 non-trivial computation. */
686 {
691 }
693 /* If the value is expensive, and we are inside an appropriately
694 short loop, put the value into a pseudo and then put the pseudo
695 into the hard reg.
697 For small register classes, also do this if this call uses
698 register parameters. This is to avoid reload conflicts while
699 loading the parameters registers. */
709 }
710 }
712 #ifdef REG_PARM_STACK_SPACE
714 /* The argument list is the property of the called routine and it
715 may clobber it. If the fixed area has been used for previous
716 parameters, we must save and restore it. */
718 static rtx
719 save_fixed_argument_area (int reg_parm_stack_space, rtx argblock, int *low_to_save, int *high_to_save)
720 {
724 /* Compute the boundary of the area that needs to be saved, if any. */
726 #ifdef ARGS_GROW_DOWNWARD
728 #endif
734 {
738 rtx stack_area;
739 rtx save_area;
742 ;
750 /* If we don't have the required alignment, must do this
751 in BLKmode. */
756 #ifdef ARGS_GROW_DOWNWARD
758 #else
760 #endif
764 delta)));
768 {
772 }
773 else
774 {
777 }
780 }
783 }
785 static void
787 {
790 rtx stack_area;
792 #ifdef ARGS_GROW_DOWNWARD
794 #else
796 #endif
804 else
807 BLOCK_OP_CALL_PARM);
808 }
811 /* If any elements in ARGS refer to parameters that are to be passed in
812 registers, but not in memory, and whose alignment does not permit a
813 direct copy into registers. Copy the values into a group of pseudos
814 which we will later copy into the appropriate hard registers.
816 Pseudos for each unaligned argument will be stored into the array
817 args[argnum].aligned_regs. The caller is responsible for deallocating
818 the aligned_regs array if it is nonzero. */
820 static void
822 {
830 {
835 {
838 }
839 else
840 {
843 }
847 /* Structures smaller than a word are normally aligned to the
848 least significant byte. On a BYTES_BIG_ENDIAN machine,
849 this means we must skip the empty high order bytes when
850 calculating the bit offset. */
852 #ifdef BLOCK_REG_PADDING
856 #else
857 && BYTES_BIG_ENDIAN
858 #endif
859 )
863 {
872 /* There is no need to restrict this code to loading items
873 in TYPE_ALIGN sized hunks. The bitfield instructions can
874 load up entire word sized registers efficiently.
876 ??? This may not be needed anymore.
877 We use to emit a clobber here but that doesn't let later
878 passes optimize the instructions we emit. By storing 0 into
879 the register later passes know the first AND to zero out the
880 bitfield being set in the register is unnecessary. The store
881 of 0 will be deleted as will at least the first AND. */
887 word);
888 }
889 }
890 }
892 /* Fill in ARGS_SIZE and ARGS array based on the parameters found in
893 ACTPARMS.
895 NUM_ACTUALS is the total number of parameters.
897 N_NAMED_ARGS is the total number of named arguments.
899 FNDECL is the tree code for the target of this call (if known)
901 ARGS_SO_FAR holds state needed by the target to know where to place
902 the next argument.
904 REG_PARM_STACK_SPACE is the number of bytes of stack space reserved
905 for arguments which are passed in registers.
907 OLD_STACK_LEVEL is a pointer to an rtx which olds the old stack level
908 and may be modified by this routine.
910 OLD_PENDING_ADJ, MUST_PREALLOCATE and FLAGS are pointers to integer
911 flags which may may be modified by this routine.
913 MAY_TAILCALL is cleared if we encounter an invisible pass-by-reference
914 that requires allocation of stack space.
916 CALL_FROM_THUNK_P is true if this call is the jump from a thunk to
917 the thunked-to function. */
919 static void
930 {
931 /* 1 if scanning parms front to back, -1 if scanning back to front. */
934 /* Count arg position in order args appear. */
938 tree p;
943 /* In this loop, we consider args in the order they are written.
944 We fill up ARGS from the front or from the back if necessary
945 so that in any case the first arg to be pushed ends up at the front. */
948 {
950 /* In this case, must reverse order of args
951 so that we compute and push the last arg first. */
952 }
953 else
954 {
956 }
958 /* I counts args in order (to be) pushed; ARGPOS counts in order written. */
960 {
967 /* Replace erroneous argument with constant zero. */
971 /* If TYPE is a transparent union, pass things the way we would
972 pass the first field of the union. We have already verified that
973 the modes are the same. */
977 /* Decide where to pass this arg.
979 args[i].reg is nonzero if all or part is passed in registers.
981 args[i].partial is nonzero if part but not all is passed in registers,
982 and the exact value says how many bytes are passed in registers.
984 args[i].pass_on_stack is nonzero if the argument must at least be
985 computed on the stack. It may then be loaded back into registers
986 if args[i].reg is nonzero.
988 These decisions are driven by the FUNCTION_... macros and must agree
989 with those made by function.c. */
991 /* See if this argument should be passed by invisible reference. */
994 {
996 tree base;
998 callee_copies
1002 /* If we're compiling a thunk, pass through invisible references
1003 instead of making a copy. */
1005 || (callee_copies
1009 {
1010 /* We can't use sibcalls if a callee-copied argument is
1011 stored in the current function's frame. */
1019 }
1020 else
1021 {
1022 /* We make a copy of the object and pass the address to the
1023 function being called. */
1024 rtx copy;
1030 STACK_CHECK_MAX_VAR_SIZE))))
1031 {
1032 /* This is a variable-sized object. Make space on the stack
1033 for it. */
1037 {
1041 }
1044 allocate_dynamic_stack_space
1047 }
1048 else
1055 else
1062 }
1063 }
1076 #ifdef FUNCTION_INCOMING_ARG
1077 /* If this is a sibling call and the machine has register windows, the
1078 register window has to be unwinded before calling the routine, so
1079 arguments have to go into the incoming registers. */
1082 #else
1084 #endif
1093 /* If FUNCTION_ARG returned a (parallel [(expr_list (nil) ...) ...]),
1094 it means that we are to pass this arg in the register(s) designated
1095 by the PARALLEL, but also to pass it in the stack. */
1100 /* If this is an addressable type, we must preallocate the stack
1101 since we must evaluate the object into its final location.
1103 If this is to be passed in both registers and the stack, it is simpler
1104 to preallocate. */
1109 /* If this is an addressable type, we cannot pre-evaluate it. Thus,
1110 we cannot consider this function call constant. */
1114 /* Compute the stack-size of this argument. */
1119 #ifdef STACK_PARMS_IN_REG_PARM_AREA
1121 #else
1123 #endif
1126 #ifdef BLOCK_REG_PADDING
1127 else
1128 /* The argument is passed entirely in registers. See at which
1129 end it should be padded. */
1133 #endif
1135 /* Update ARGS_SIZE, the total stack space for args so far. */
1141 /* Increment ARGS_SO_FAR, which has info about which arg-registers
1142 have been used, etc. */
1146 }
1147 }
1149 /* Update ARGS_SIZE to contain the total size for the argument block.
1150 Return the original constant component of the argument block's size.
1152 REG_PARM_STACK_SPACE holds the number of bytes of stack space reserved
1153 for arguments passed in registers. */
1155 static int
1159 {
1162 /* For accumulate outgoing args mode we don't need to align, since the frame
1163 will be already aligned. Align to STACK_BOUNDARY in order to prevent
1164 backends from generating misaligned frame sizes. */
1168 /* Compute the actual size of the argument block required. The variable
1169 and constant sizes must be combined, the size may have to be rounded,
1170 and there may be a minimum required size. */
1173 {
1179 {
1180 /* We don't handle this case yet. To handle it correctly we have
1181 to add the delta, round and subtract the delta.
1182 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. */
1242 /* If we preallocated the stack space, and some arguments must be passed
1243 on the stack, then we must precompute any parameter which contains a
1244 function call which will store arguments on the stack.
1245 Otherwise, evaluating the parameter may clobber previous parameters
1246 which have already been stored into the stack. (we have code to avoid
1247 such case by saving the outgoing stack arguments, but it results in
1248 worse code) */
1253 {
1260 /* If this is an addressable type, we cannot pre-evaluate it. */
1268 {
1272 #if defined(PROMOTE_FUNCTION_MODE) && !defined(PROMOTE_MODE)
1273 /* CSE will replace this only if it contains args[i].value
1274 pseudo, so convert it down to the declared mode using
1275 a SUBREG. */
1278 {
1284 }
1285 #endif
1286 }
1287 }
1288 }
1290 /* Given the current state of MUST_PREALLOCATE and information about
1291 arguments to a function call in NUM_ACTUALS, ARGS and ARGS_SIZE,
1292 compute and return the final value for MUST_PREALLOCATE. */
1294 static int
1295 finalize_must_preallocate (int must_preallocate, int num_actuals, struct arg_data *args, struct args_size *args_size)
1296 {
1297 /* See if we have or want to preallocate stack space.
1299 If we would have to push a partially-in-regs parm
1300 before other stack parms, preallocate stack space instead.
1302 If the size of some parm is not a multiple of the required stack
1303 alignment, we must preallocate.
1305 If the total size of arguments that would otherwise create a copy in
1306 a temporary (such as a CALL) is more than half the total argument list
1307 size, preallocation is faster.
1309 Another reason to preallocate is if we have a machine (like the m88k)
1310 where stack alignment is required to be maintained between every
1311 pair of insns, not just when the call is made. However, we assume here
1312 that such machines either do not have push insns (and hence preallocation
1313 would occur anyway) or the problem is taken care of with
1314 PUSH_ROUNDING. */
1317 {
1323 {
1334 copy_to_evaluate_size
1336 }
1341 }
1343 }
1345 /* If we preallocated stack space, compute the address of each argument
1346 and store it into the ARGS array.
1348 We need not ensure it is a valid memory address here; it will be
1349 validized when it is used.
1351 ARGBLOCK is an rtx for the address of the outgoing arguments. */
1353 static void
1355 {
1357 {
1365 {
1368 rtx addr;
1373 /* Skip this parm if it will not be passed on the stack. */
1381 else
1387 {
1388 /* Only part of the parameter is being passed on the stack.
1389 Generate a simple memory reference of the correct size. */
1395 }
1396 else
1397 {
1401 }
1407 {
1410 }
1415 else
1421 {
1422 /* Only part of the parameter is being passed on the stack.
1423 Generate a simple memory reference of the correct size. */
1426 }
1427 else
1428 {
1432 }
1435 /* Function incoming arguments may overlap with sibling call
1436 outgoing arguments and we cannot allow reordering of reads
1437 from function arguments with stores to outgoing arguments
1438 of sibling calls. */
1441 }
1442 }
1443 }
1445 /* Given a FNDECL and EXP, return an rtx suitable for use as a target address
1446 in a call instruction.
1448 FNDECL is the tree node for the target function. For an indirect call
1449 FNDECL will be NULL_TREE.
1451 ADDR is the operand 0 of CALL_EXPR for this call. */
1453 static rtx
1455 {
1456 rtx funexp;
1458 /* Get the function to call, in the form of RTL. */
1460 {
1461 /* If this is the first use of the function, see if we need to
1462 make an external definition for it. */
1464 {
1467 }
1469 /* Get a SYMBOL_REF rtx for the function address. */
1471 }
1472 else
1473 /* Generate an rtx (probably a pseudo-register) for the address. */
1474 {
1478 }
1480 }
1482 /* Return true if and only if SIZE storage units (usually bytes)
1483 starting from address ADDR overlap with already clobbered argument
1484 area. This function is used to determine if we should give up a
1485 sibcall. */
1487 static bool
1489 {
1490 HOST_WIDE_INT i;
1498 /* Return true for arg pointer based indexed addressing. */
1503 else
1506 #ifdef ARGS_GROW_DOWNWARD
1508 #endif
1510 {
1517 }
1520 }
1522 /* Do the register loads required for any wholly-register parms or any
1523 parms which are passed both on the stack and in a register. Their
1524 expressions were already evaluated.
1526 Mark all register-parms as living through the call, putting these USE
1527 insns in the CALL_INSN_FUNCTION_USAGE field.
1529 When IS_SIBCALL, perform the check_sibcall_argument_overlap
1530 checking, setting *SIBCALL_FAILURE if appropriate. */
1532 static void
1536 {
1540 {
1544 {
1549 /* Set non-negative if we must move a word at a time, even if
1550 just one word (e.g, partial == 4 && mode == DFmode). Set
1551 to -1 if we just use a normal move insn. This value can be
1552 zero if the argument is a zero size structure. */
1555 ;
1557 {
1560 }
1562 {
1565 }
1566 else
1569 /* Handle calls that pass values in multiple non-contiguous
1570 locations. The Irix 6 ABI has examples of this. */
1575 /* If simple case, just do move. If normal partial, store_one_arg
1576 has already loaded the register for us. In all other cases,
1577 load the register(s) from memory. */
1580 {
1582 #ifdef BLOCK_REG_PADDING
1583 /* Handle case where we have a value that needs shifting
1584 up to the msb. eg. a QImode value and we're padding
1585 upward on a BYTES_BIG_ENDIAN machine. */
1589 {
1590 rtx x;
1593 /* Assigning REG here rather than a temp makes CALL_FUSAGE
1594 report the whole reg as used. Strictly speaking, the
1595 call only uses SIZE bytes at the msb end, but it doesn't
1596 seem worth generating rtl to say that. */
1603 }
1604 #endif
1605 }
1607 /* If we have pre-computed the values to put in the registers in
1608 the case of non-aligned structures, copy them in now. */
1616 {
1619 /* Check for overlap with already clobbered argument area. */
1622 size))
1625 /* Handle a BLKmode that needs shifting. */
1627 #ifdef BLOCK_REG_PADDING
1629 #else
1630 && BYTES_BIG_ENDIAN
1631 #endif
1632 )
1633 {
1647 }
1648 else
1650 }
1652 /* When a parameter is a block, and perhaps in other cases, it is
1653 possible that it did a load from an argument slot that was
1654 already clobbered. */
1659 /* Handle calls that pass values in multiple non-contiguous
1660 locations. The Irix 6 ABI has examples of this. */
1667 }
1668 }
1669 }
1671 /* We need to pop PENDING_STACK_ADJUST bytes. But, if the arguments
1672 wouldn't fill up an even multiple of PREFERRED_UNIT_STACK_BOUNDARY
1673 bytes, then we would need to push some additional bytes to pad the
1674 arguments. So, we compute an adjust to the stack pointer for an
1675 amount that will leave the stack under-aligned by UNADJUSTED_ARGS_SIZE
1676 bytes. Then, when the arguments are pushed the stack will be perfectly
1677 aligned. ARGS_SIZE->CONSTANT is set to the number of bytes that should
1678 be popped after the call. Returns the adjustment. */
1680 static int
1684 {
1685 /* The number of bytes to pop so that the stack will be
1686 under-aligned by UNADJUSTED_ARGS_SIZE bytes. */
1687 HOST_WIDE_INT adjustment;
1688 /* The alignment of the stack after the arguments are pushed, if we
1689 just pushed the arguments without adjust the stack here. */
1692 unadjusted_alignment
1696 /* We want to get rid of as many of the PENDING_STACK_ADJUST bytes
1697 as possible -- leaving just enough left to cancel out the
1698 UNADJUSTED_ALIGNMENT. In other words, we want to ensure that the
1699 PENDING_STACK_ADJUST is non-negative, and congruent to
1700 -UNADJUSTED_ALIGNMENT modulo the PREFERRED_UNIT_STACK_BOUNDARY. */
1702 /* Begin by trying to pop all the bytes. */
1703 unadjusted_alignment
1704 = (unadjusted_alignment
1707 /* Push enough additional bytes that the stack will be aligned
1708 after the arguments are pushed. */
1710 {
1713 else
1715 }
1717 /* Now, sets ARGS_SIZE->CONSTANT so that we pop the right number of
1718 bytes after the call. The right number is the entire
1719 PENDING_STACK_ADJUST less our ADJUSTMENT plus the amount required
1720 by the arguments in the first place. */
1721 args_size->constant
1725 }
1727 /* Scan X expression if it does not dereference any argument slots
1728 we already clobbered by tail call arguments (as noted in stored_args_map
1729 bitmap).
1730 Return nonzero if X expression dereferences such argument slots,
1731 zero otherwise. */
1733 static int
1735 {
1736 RTX_CODE code;
1749 /* Scan all subexpressions. */
1752 {
1754 {
1757 }
1759 {
1763 }
1764 }
1766 }
1768 /* Scan sequence after INSN if it does not dereference any argument slots
1769 we already clobbered by tail call arguments (as noted in stored_args_map
1770 bitmap). If MARK_STORED_ARGS_MAP, add stack slots for ARG to
1771 stored_args_map bitmap afterwards (when ARG is a register MARK_STORED_ARGS_MAP
1772 should be 0). Return nonzero if sequence after INSN dereferences such argument
1773 slots, zero otherwise. */
1775 static int
1777 {
1782 else
1791 {
1792 #ifdef ARGS_GROW_DOWNWARD
1794 #else
1796 #endif
1800 }
1802 }
1804 /* Given that a function returns a value of mode MODE at the most
1805 significant end of hard register VALUE, shift VALUE left or right
1806 as specified by LEFT_P. Return true if some action was needed. */
1808 bool
1810 {
1811 HOST_WIDE_INT shift;
1818 /* Use ashr rather than lshr for right shifts. This is for the benefit
1819 of the MIPS port, which requires SImode values to be sign-extended
1820 when stored in 64-bit registers. */
1825 }
1827 /* Generate all the code for a function call
1828 and return an rtx for its value.
1829 Store the value in TARGET (specified as an rtx) if convenient.
1830 If the value is stored in TARGET then TARGET is returned.
1831 If IGNORE is nonzero, then we ignore the value of the function call. */
1833 rtx
1835 {
1836 /* Nonzero if we are currently expanding a call. */
1839 /* List of actual parameters. */
1841 /* RTX for the function to be called. */
1842 rtx funexp;
1843 /* Sequence of insns to perform a normal "call". */
1845 /* Sequence of insns to perform a tail "call". */
1847 /* Data type of the function. */
1848 tree funtype;
1849 tree type_arg_types;
1850 /* Declaration of the function being called,
1851 or 0 if the function is computed (not known by name). */
1853 /* The type of the function being called. */
1854 tree fntype;
1858 /* Register in which non-BLKmode value will be returned,
1859 or 0 if no value or if value is BLKmode. */
1860 rtx valreg;
1861 /* Address where we should return a BLKmode value;
1862 0 if value not BLKmode. */
1864 /* Nonzero if that address is being passed by treating it as
1865 an extra, implicit first parameter. Otherwise,
1866 it is passed by being copied directly into struct_value_rtx. */
1868 /* Size of aggregate value wanted, or zero if none wanted
1869 or if we are using the non-reentrant PCC calling convention
1870 or expecting the value in registers. */
1872 /* Nonzero if called function returns an aggregate in memory PCC style,
1873 by returning the address of where to find it. */
1877 /* Number of actual parameters in this call, including struct value addr. */
1879 /* Number of named args. Args after this are anonymous ones
1880 and they must all go on the stack. */
1883 /* Vector of information about each argument.
1884 Arguments are numbered in the order they will be pushed,
1885 not the order they are written. */
1888 /* Total size in bytes of all the stack-parms scanned so far. */
1891 /* Size of arguments before any adjustments (such as rounding). */
1893 /* Data on reg parms scanned so far. */
1894 CUMULATIVE_ARGS args_so_far;
1895 /* Nonzero if a reg parm has been scanned. */
1897 /* Nonzero if this is an indirect function call. */
1899 /* Nonzero if we must avoid push-insns in the args for this call.
1900 If stack space is allocated for register parameters, but not by the
1901 caller, then it is preallocated in the fixed part of the stack frame.
1902 So the entire argument block must then be preallocated (i.e., we
1903 ignore PUSH_ROUNDING in that case). */
1907 /* Size of the stack reserved for parameter registers. */
1910 /* Address of space preallocated for stack parms
1911 (on machines that lack push insns), or 0 if space not preallocated. */
1914 /* Mask of ECF_ flags. */
1916 #ifdef REG_PARM_STACK_SPACE
1917 /* Define the boundary of the register parm stack space that needs to be
1918 saved, if any. */
1921 #endif
1929 /* State variables to track stack modifications. */
1935 /* Some stack pointer alterations we make are performed via
1936 allocate_dynamic_stack_space. This modifies the stack_pointer_delta,
1937 which we then also need to save/restore along the way. */
1940 rtx call_fusage;
1944 /* The alignment of the stack, in bits. */
1946 /* The alignment of the stack, in bytes. */
1948 /* The static chain value to use for this call. */
1949 rtx static_chain_value;
1950 /* See if this is "nothrow" function call. */
1954 /* See if we can find a DECL-node for the actual function, and get the
1955 function attributes (flags) from the function decl or type node. */
1958 {
1961 }
1962 else
1963 {
1966 }
1970 /* Warn if this value is an aggregate type,
1971 regardless of which calling convention we are using for it. */
1975 /* If the result of a pure or const function call is ignored (or void),
1976 and none of its arguments are volatile, we can avoid expanding the
1977 call and just evaluate the arguments for side-effects. */
1981 {
1983 tree arg;
1987 {
1990 }
1993 {
1998 }
1999 }
2001 #ifdef REG_PARM_STACK_SPACE
2003 #endif
2005 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2008 #endif
2010 /* Set up a place to return a structure. */
2012 /* Cater to broken compilers. */
2014 {
2015 /* This call returns a big structure. */
2018 #ifdef PCC_STATIC_STRUCT_RETURN
2019 {
2021 }
2023 {
2028 else
2029 {
2030 /* For variable-sized objects, we must be called with a target
2031 specified. If we were to allocate space on the stack here,
2032 we would have no way of knowing when to free it. */
2038 }
2039 }
2041 }
2043 /* Figure out the amount to which the stack should be aligned. */
2046 {
2050 }
2052 /* Operand 0 is a pointer-to-function; get the type of the function. */
2057 /* Munge the tree to split complex arguments into their imaginary
2058 and real parts. */
2060 {
2063 }
2064 else
2070 /* If struct_value_rtx is 0, it means pass the address
2071 as if it were an extra parameter. */
2073 {
2074 /* If structure_value_addr is a REG other than
2075 virtual_outgoing_args_rtx, we can use always use it. If it
2076 is not a REG, we must always copy it into a register.
2077 If it is virtual_outgoing_args_rtx, we must copy it to another
2078 register in some cases. */
2080 || (ACCUMULATE_OUTGOING_ARGS
2081 && stack_arg_under_construction
2087 actparms
2090 temp),
2091 actparms);
2093 }
2095 /* Count the arguments and set NUM_ACTUALS. */
2097 num_actuals++;
2099 /* Compute number of named args.
2100 First, do a raw count of the args for INIT_CUMULATIVE_ARGS. */
2103 n_named_args
2105 /* Count the struct value address, if it is passed as a parm. */
2107 else
2108 /* If we know nothing, treat all args as named. */
2111 /* Start updating where the next arg would go.
2113 On some machines (such as the PA) indirect calls have a different
2114 calling convention than normal calls. The fourth argument in
2115 INIT_CUMULATIVE_ARGS tells the backend if this is an indirect call
2116 or not. */
2119 /* Now possibly adjust the number of named args.
2120 Normally, don't include the last named arg if anonymous args follow.
2121 We do include the last named arg if
2122 targetm.calls.strict_argument_naming() returns nonzero.
2123 (If no anonymous args follow, the result of list_length is actually
2124 one too large. This is harmless.)
2126 If targetm.calls.pretend_outgoing_varargs_named() returns
2127 nonzero, and targetm.calls.strict_argument_naming() returns zero,
2128 this machine will be able to place unnamed args that were passed
2129 in registers into the stack. So treat all args as named. This
2130 allows the insns emitting for a specific argument list to be
2131 independent of the function declaration.
2133 If targetm.calls.pretend_outgoing_varargs_named() returns zero,
2134 we do not have any reliable way to pass unnamed args in
2135 registers, so we must force them into memory. */
2139 ;
2142 /* Don't include the last named arg. */
2144 else
2145 /* Treat all args as named. */
2148 /* Make a vector to hold all the information about each arg. */
2152 /* Build up entries in the ARGS array, compute the size of the
2153 arguments into ARGS_SIZE, etc. */
2162 {
2163 /* If this function requires a variable-sized argument list, don't
2164 try to make a cse'able block for this call. We may be able to
2165 do this eventually, but it is too complicated to keep track of
2166 what insns go in the cse'able block and which don't. */
2170 }
2172 /* Now make final decision about preallocating stack space. */
2177 /* If the structure value address will reference the stack pointer, we
2178 must stabilize it. We don't need to do this if we know that we are
2179 not going to adjust the stack pointer in processing this call. */
2184 structure_value_addr))
2189 /* Tail calls can make things harder to debug, and we've traditionally
2190 pushed these optimizations into -O2. Don't try if we're already
2191 expanding a call, as that means we're an argument. Don't try if
2192 there's cleanups, as we know there's code to follow the call. */
2195 || !flag_optimize_sibling_calls
2200 /* Rest of purposes for tail call optimizations to fail. */
2202 #ifdef HAVE_sibcall_epilogue
2203 !HAVE_sibcall_epilogue
2204 #else
2205 1
2206 #endif
2207 || !try_tail_call
2208 /* Doing sibling call optimization needs some work, since
2209 structure_value_addr can be allocated on the stack.
2210 It does not seem worth the effort since few optimizable
2211 sibling calls will return a structure. */
2213 /* Check whether the target is able to optimize the call
2214 into a sibcall. */
2216 /* Functions that do not return exactly once may not be sibcall
2217 optimized. */
2220 /* If the called function is nested in the current one, it might access
2221 some of the caller's arguments, but could clobber them beforehand if
2222 the argument areas are shared. */
2224 /* If this function requires more stack slots than the current
2225 function, we cannot change it into a sibling call.
2226 current_function_pretend_args_size is not part of the
2227 stack allocated by our caller. */
2230 /* If the callee pops its own arguments, then it must pop exactly
2231 the same number of arguments as the current function. */
2235 current_function_args_size))
2239 /* Ensure current function's preferred stack boundary is at least
2240 what we need. We don't have to increase alignment for recursive
2241 functions. */
2250 /* We want to make two insn chains; one for a sibling call, the other
2251 for a normal call. We will select one of the two chains after
2252 initial RTL generation is complete. */
2254 {
2256 /* We want to emit any pending stack adjustments before the tail
2257 recursion "call". That way we know any adjustment after the tail
2258 recursion call can be ignored if we indeed use the tail
2259 call expansion. */
2262 rtx insns;
2266 {
2267 /* State variables we need to save and restore between
2268 iterations. */
2271 }
2274 else
2277 /* Other state variables that we must reinitialize each time
2278 through the loop (that are not initialized by the loop itself). */
2282 /* Start a new sequence for the normal call case.
2284 From this point on, if the sibling call fails, we want to set
2285 sibcall_failure instead of continuing the loop. */
2288 /* Don't let pending stack adjusts add up to too much.
2289 Also, do all pending adjustments now if there is any chance
2290 this might be a call to alloca or if we are expanding a sibling
2291 call sequence or if we are calling a function that is to return
2292 with stack pointer depressed.
2293 Also do the adjustments before a throwing call, otherwise
2294 exception handling can fail; PR 19225. */
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. */
2321 /* Compute the actual size of the argument block required. The variable
2322 and constant sizes must be combined, the size may have to be rounded,
2323 and there may be a minimum required size. When generating a sibcall
2324 pattern, do not round up, since we'll be re-using whatever space our
2325 caller provided. */
2326 unadjusted_args_size
2334 /* The argument block when performing a sibling call is the
2335 incoming argument block. */
2337 {
2339 argblock
2340 #ifdef STACK_GROWS_DOWNWARD
2342 #else
2344 #endif
2347 }
2349 /* If we have no actual push instructions, or shouldn't use them,
2350 make space for all args right now. */
2352 {
2354 {
2359 /* stack_arg_under_construction says whether a stack arg is
2360 being constructed at the old stack level. Pushing the stack
2361 gets a clean outgoing argument block. */
2364 }
2366 }
2367 else
2368 {
2369 /* Note that we must go through the motions of allocating an argument
2370 block even if the size is zero because we may be storing args
2371 in the area reserved for register arguments, which may be part of
2372 the stack frame. */
2376 /* Store the maximum argument space used. It will be pushed by
2377 the prologue (if ACCUMULATE_OUTGOING_ARGS, or stack overflow
2378 checking). */
2384 {
2386 {
2387 /* Since the stack pointer will never be pushed, it is
2388 possible for the evaluation of a parm to clobber
2389 something we have already written to the stack.
2390 Since most function calls on RISC machines do not use
2391 the stack, this is uncommon, but must work correctly.
2393 Therefore, we save any area of the stack that was already
2394 written and that we are using. Here we set up to do this
2395 by making a new stack usage map from the old one. The
2396 actual save will be done by store_one_arg.
2398 Another approach might be to try to reorder the argument
2399 evaluations to avoid this conflicting stack usage. */
2401 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2402 /* Since we will be writing into the entire argument area,
2403 the map must be allocated for its entire size, not just
2404 the part that is the responsibility of the caller. */
2406 #endif
2408 #ifdef ARGS_GROW_DOWNWARD
2411 #else
2413 needed);
2414 #endif
2422 initial_highest_arg_in_use);
2426 (highest_outgoing_arg_in_use
2430 /* The address of the outgoing argument list must not be
2431 copied to a register here, because argblock would be left
2432 pointing to the wrong place after the call to
2433 allocate_dynamic_stack_space below. */
2436 }
2437 else
2438 {
2440 {
2441 /* Try to reuse some or all of the pending_stack_adjust
2442 to get this space. */
2443 needed
2444 = (combine_pending_stack_adjustment_and_call
2447 preferred_unit_stack_boundary));
2449 /* combine_pending_stack_adjustment_and_call computes
2450 an adjustment before the arguments are allocated.
2451 Account for them and see whether or not the stack
2452 needs to go up or down. */
2456 {
2457 /* We're releasing stack space. */
2458 /* ??? We can avoid any adjustment at all if we're
2459 already aligned. FIXME. */
2463 }
2464 else
2465 /* We need to allocate space. We'll do that in
2466 push_block below. */
2468 }
2470 /* Special case this because overhead of `push_block' in
2471 this case is non-trivial. */
2474 else
2475 {
2477 #ifdef ARGS_GROW_DOWNWARD
2479 #endif
2480 }
2482 /* We only really need to call `copy_to_reg' in the case
2483 where push insns are going to be used to pass ARGBLOCK
2484 to a function call in ARGS. In that case, the stack
2485 pointer changes value from the allocation point to the
2486 call point, and hence the value of
2487 VIRTUAL_OUTGOING_ARGS_RTX changes as well. But might
2488 as well always do it. */
2490 }
2491 }
2492 }
2495 {
2496 /* The save/restore code in store_one_arg handles all
2497 cases except one: a constructor call (including a C
2498 function returning a BLKmode struct) to initialize
2499 an argument. */
2501 {
2502 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2505 #else
2507 #endif
2509 {
2511 NULL_RTX);
2515 /* stack_arg_under_construction says whether a stack
2516 arg is being constructed at the old stack level.
2517 Pushing the stack gets a clean outgoing argument
2518 block. */
2519 old_stack_arg_under_construction
2522 /* Make a new map for the new argument list. */
2529 }
2531 BITS_PER_UNIT);
2532 }
2534 /* If argument evaluation might modify the stack pointer,
2535 copy the address of the argument list to a register. */
2538 {
2541 }
2542 }
2546 /* If we push args individually in reverse order, perform stack alignment
2547 before the first push (the last arg). */
2550 {
2551 /* When the stack adjustment is pending, we get better code
2552 by combining the adjustments. */
2556 {
2557 pending_stack_adjust
2558 = (combine_pending_stack_adjustment_and_call
2561 preferred_unit_stack_boundary));
2563 }
2567 }
2568 /* Now that the stack is properly aligned, pops can't safely
2569 be deferred during the evaluation of the arguments. */
2570 NO_DEFER_POP;
2574 /* Figure out the register where the value, if any, will come back. */
2578 {
2582 else
2585 }
2587 /* Precompute all register parameters. It isn't safe to compute anything
2588 once we have started filling any specific hard regs. */
2593 else
2596 #ifdef REG_PARM_STACK_SPACE
2597 /* Save the fixed argument area if it's part of the caller's frame and
2598 is clobbered by argument setup for this call. */
2602 #endif
2604 /* Now store (and compute if necessary) all non-register parms.
2605 These come before register parms, since they can require block-moves,
2606 which could clobber the registers used for register parms.
2607 Parms which have partial registers are not stored here,
2608 but we do preallocate space here if they want that. */
2612 {
2617 reg_parm_stack_space)
2629 call_fusage);
2630 }
2632 /* If we have a parm that is passed in registers but not in memory
2633 and whose alignment does not permit a direct copy into registers,
2634 make a group of pseudos that correspond to each register that we
2635 will later fill. */
2639 /* Now store any partially-in-registers parm.
2640 This is the last place a block-move can happen. */
2644 {
2649 reg_parm_stack_space)
2654 }
2656 /* If we pushed args in forward order, perform stack alignment
2657 after pushing the last arg. */
2662 /* If register arguments require space on the stack and stack space
2663 was not preallocated, allocate stack space here for arguments
2664 passed in registers. */
2665 #ifdef OUTGOING_REG_PARM_STACK_SPACE
2669 #endif
2671 /* Pass the function the address in which to return a
2672 structure value. */
2674 {
2675 structure_value_addr
2680 NULL_RTX)));
2684 }
2692 /* Save a pointer to the last insn before the call, so that we can
2693 later safely search backwards to find the CALL_INSN. */
2696 /* Set up next argument register. For sibling calls on machines
2697 with register windows this should be the incoming register. */
2698 #ifdef FUNCTION_INCOMING_ARG
2702 else
2703 #endif
2707 /* All arguments and registers used for the call must be set up by
2708 now! */
2710 /* Stack must be properly aligned now. */
2714 /* Generate the actual call instruction. */
2720 /* If a non-BLKmode value is returned at the most significant end
2721 of a register, shift the register right by the appropriate amount
2722 and update VALREG accordingly. BLKmode values are handled by the
2723 group load/store machinery below. */
2725 && !pcc_struct_value
2728 {
2732 }
2734 /* If call is cse'able, make appropriate pair of reg-notes around it.
2735 Test valreg so we don't crash; may safely ignore `const'
2736 if return type is void. Disable for PARALLEL return values, because
2737 we have no way to move such values into a pseudo register. */
2739 {
2740 rtx insns;
2741 rtx insn;
2746 /* Expansion of block moves possibly introduced a loop that may
2747 not appear inside libcall block. */
2753 {
2756 }
2757 else
2758 {
2762 /* Mark the return value as a pointer if needed. */
2769 && fndecl
2777 else
2778 {
2779 /* Construct an "equal form" for the value which
2780 mentions all the arguments in order as well as
2781 the function name. */
2792 note);
2793 }
2797 }
2798 }
2800 {
2804 /* The return value from a malloc-like function is a pointer. */
2810 /* The return value from a malloc-like function can not alias
2811 anything else. */
2816 /* Write out the sequence. */
2821 }
2823 /* For calls to `setjmp', etc., inform flow.c it should complain
2824 if nonvolatile values are live. For functions that cannot return,
2825 inform flow that control does not fall through. */
2828 {
2829 /* The barrier must be emitted
2830 immediately after the CALL_INSN. Some ports emit more
2831 than just a CALL_INSN above, so we must search for it here. */
2835 {
2837 /* There was no CALL_INSN? */
2839 }
2843 /* Stack adjustments after a noreturn call are dead code.
2844 However when NO_DEFER_POP is in effect, we must preserve
2845 stack_pointer_delta. */
2847 {
2850 }
2851 }
2853 /* If value type not void, return an rtx for the value. */
2859 {
2861 {
2862 target
2865 structure_value_addr));
2867 }
2868 }
2870 {
2871 /* This is the special C++ case where we need to
2872 know what the true target was. We take care to
2873 never use this value more than once in one expression. */
2877 }
2878 /* Handle calls that return values in multiple non-contiguous locations.
2879 The Irix 6 ABI has examples of this. */
2881 {
2883 {
2884 /* This will only be assigned once, so it can be readonly. */
2890 }
2896 /* We can not support sibling calls for this case. */
2898 }
2902 {
2905 /* We have to copy a return value in a CLASS_LIKELY_SPILLED hard
2906 reg to a plain register. */
2913 /* If TARGET is a MEM in the argument area, and we have
2914 saved part of the argument area, then we can't store
2915 directly into TARGET as it may get overwritten when we
2916 restore the argument save area below. Don't work too
2917 hard though and simply force TARGET to a register if it
2918 is a MEM; the optimizer is quite likely to sort it out. */
2922 {
2925 }
2929 else
2930 {
2931 /* TARGET and VALREG cannot be equal at this point
2932 because the latter would not have
2933 REG_FUNCTION_VALUE_P true, while the former would if
2934 it were referring to the same register.
2936 If they refer to the same register, this move will be
2937 a no-op, except when function inlining is being
2938 done. */
2941 /* If we are setting a MEM, this code must be executed.
2942 Since it is emitted after the call insn, sibcall
2943 optimization cannot be performed in that case. */
2946 }
2947 }
2949 {
2952 /* We can not support sibling calls for this case. */
2954 }
2955 else
2959 {
2960 /* If we promoted this return value, make the proper SUBREG.
2961 TARGET might be const0_rtx here, so be careful. */
2965 {
2972 /* If we don't promote as expected, something is wrong. */
2978 {
2985 }
2989 }
2990 }
2992 /* If size of args is variable or this was a constructor call for a stack
2993 argument, restore saved stack-pointer value. */
2996 {
3005 }
3007 {
3008 #ifdef REG_PARM_STACK_SPACE
3012 #endif
3014 /* If we saved any argument areas, restore them. */
3017 {
3019 rtx stack_area
3026 else
3029 BLOCK_OP_CALL_PARM);
3030 }
3034 }
3036 /* If this was alloca, record the new stack level for nonlocal gotos.
3037 Check for the handler slots since we might not have a save area
3038 for non-local gotos. */
3043 /* Free up storage we no longer need. */
3052 {
3055 /* Restore the pending stack adjustment now that we have
3056 finished generating the sibling call sequence. */
3061 /* Prepare arg structure for next iteration. */
3063 {
3067 }
3070 }
3071 else
3072 {
3075 /* Verify that we've deallocated all the stack we used. */
3077 || (old_stack_allocated
3079 }
3081 /* If something prevents making this a sibling call,
3082 zero out the sequence. */
3085 else
3087 }
3089 /* If tail call production succeeded, we need to remove REG_EQUIV notes on
3090 arguments too, as argument area is now clobbered by the call. */
3092 {
3095 }
3096 else
3099 currently_expanding_call--;
3101 /* If this function returns with the stack pointer depressed, ensure
3102 this block saves and restores the stack pointer, show it was
3103 changed, and adjust for any outgoing arg space. */
3105 {
3109 }
3115 }
3117 /* A sibling call sequence invalidates any REG_EQUIV notes made for
3118 this function's incoming arguments.
3120 At the start of RTL generation we know the only REG_EQUIV notes
3121 in the rtl chain are those for incoming arguments, so we can look
3122 for REG_EQUIV notes between the start of the function and the
3123 NOTE_INSN_FUNCTION_BEG.
3125 This is (slight) overkill. We could keep track of the highest
3126 argument we clobber and be more selective in removing notes, but it
3127 does not seem to be worth the effort. */
3129 void
3131 {
3132 rtx insn;
3135 {
3136 /* There are never REG_EQUIV notes for the incoming arguments
3137 after the NOTE_INSN_FUNCTION_BEG note, so stop if we see it. */
3143 {
3146 {
3147 /* Remove the note and keep looking at the notes for
3148 this insn. */
3151 }
3153 }
3154 }
3155 }
3157 /* Traverse an argument list in VALUES and expand all complex
3158 arguments into their components. */
3159 static tree
3161 {
3162 tree p;
3164 /* Before allocating memory, check for the common case of no complex. */
3166 {
3171 }
3174 found:
3178 {
3180 tree complex_type;
3188 {
3189 tree subtype;
3203 /* Skip the newly created node. */
3205 }
3206 }
3209 }
3211 /* Traverse a list of TYPES and expand all complex types into their
3212 components. */
3213 static tree
3215 {
3216 tree p;
3218 /* Before allocating memory, check for the common case of no complex. */
3220 {
3225 }
3228 found:
3232 {
3237 {
3240 /* Rewrite complex type with component type. */
3244 /* Add another component type for the imaginary part. */
3249 /* Skip the newly created node. */
3251 }
3252 }
3255 }
3256 \f
3257 /* Output a library call to function FUN (a SYMBOL_REF rtx).
3258 The RETVAL parameter specifies whether return value needs to be saved, other
3259 parameters are documented in the emit_library_call function below. */
3261 static rtx
3265 {
3266 /* Total size in bytes of all the stack-parms scanned so far. */
3268 /* Size of arguments before any adjustments (such as rounding). */
3271 rtx fun;
3275 CUMULATIVE_ARGS args_so_far;
3276 struct arg
3277 {
3278 rtx value;
3280 rtx reg;
3283 rtx save_area;
3284 };
3289 rtx valreg;
3295 rtx before_call;
3298 #ifdef REG_PARM_STACK_SPACE
3299 /* Define the boundary of the register parm stack space that needs to be
3300 save, if any. */
3303 #endif
3305 /* Size of the stack reserved for parameter registers. */
3312 #ifdef REG_PARM_STACK_SPACE
3314 #endif
3316 /* By default, library functions can not throw. */
3320 {
3344 }
3347 /* Ensure current function's preferred stack boundary is at least
3348 what we need. */
3352 /* If this kind of value comes back in memory,
3353 decide where in memory it should come back. */
3355 {
3358 {
3359 #ifdef PCC_STATIC_STRUCT_RETURN
3360 rtx pointer_reg
3370 else
3372 #endif
3373 /* This call returns a big structure. */
3375 }
3376 }
3377 else
3380 /* ??? Unfinished: must pass the memory address as an argument. */
3382 /* Copy all the libcall-arguments out of the varargs data
3383 and into a vector ARGVEC.
3385 Compute how to pass each argument. We only support a very small subset
3386 of the full argument passing conventions to limit complexity here since
3387 library functions shouldn't have many args. */
3392 #ifdef INIT_CUMULATIVE_LIBCALL_ARGS
3394 #else
3396 #endif
3403 /* Now we are about to start emitting insns that can be deleted
3404 if a libcall is deleted. */
3410 /* If there's a structure value address to be passed,
3411 either pass it in the special place, or pass it as an extra argument. */
3413 {
3416 nargs++;
3418 /* Make sure it is a reasonable operand for a move or push insn. */
3432 #ifdef STACK_PARMS_IN_REG_PARM_AREA
3434 #else
3436 #endif
3445 count++;
3446 }
3449 {
3453 /* We cannot convert the arg value to the mode the library wants here;
3454 must do it earlier where we know the signedness of the arg. */
3458 /* Make sure it is a reasonable operand for a move or push insn. */
3464 {
3465 rtx slot;
3466 int must_copy
3469 /* loop.c won't look at CALL_INSN_FUNCTION_USAGE of const/pure
3470 functions, so we have to pretend this isn't such a function. */
3472 {
3476 }
3479 /* If this was a CONST function, it is now PURE since
3480 it now reads memory. */
3482 {
3485 }
3489 else
3490 {
3494 }
3498 call_fusage);
3502 slot),
3503 call_fusage);
3507 }
3518 #ifdef STACK_PARMS_IN_REG_PARM_AREA
3520 #else
3522 #endif
3533 }
3535 /* If this machine requires an external definition for library
3536 functions, write one out. */
3541 + stack_pointer_delta
3543 / STACK_BYTES
3548 reg_parm_stack_space);
3550 #ifndef OUTGOING_REG_PARM_STACK_SPACE
3552 #endif
3558 {
3559 /* Since the stack pointer will never be pushed, it is possible for
3560 the evaluation of a parm to clobber something we have already
3561 written to the stack. Since most function calls on RISC machines
3562 do not use the stack, this is uncommon, but must work correctly.
3564 Therefore, we save any area of the stack that was already written
3565 and that we are using. Here we set up to do this by making a new
3566 stack usage map from the old one.
3568 Another approach might be to try to reorder the argument
3569 evaluations to avoid this conflicting stack usage. */
3573 #ifndef OUTGOING_REG_PARM_STACK_SPACE
3574 /* Since we will be writing into the entire argument area, the
3575 map must be allocated for its entire size, not just the part that
3576 is the responsibility of the caller. */
3578 #endif
3580 #ifdef ARGS_GROW_DOWNWARD
3583 #else
3585 needed);
3586 #endif
3592 initial_highest_arg_in_use);
3599 /* We must be careful to use virtual regs before they're instantiated,
3600 and real regs afterwards. Loop optimization, for example, can create
3601 new libcalls after we've instantiated the virtual regs, and if we
3602 use virtuals anyway, they won't match the rtl patterns. */
3606 else
3608 }
3609 else
3610 {
3613 }
3615 /* If we push args individually in reverse order, perform stack alignment
3616 before the first push (the last arg). */
3622 {
3625 }
3626 else
3627 {
3630 }
3632 #ifdef REG_PARM_STACK_SPACE
3634 {
3635 /* The argument list is the property of the called routine and it
3636 may clobber it. If the fixed area has been used for previous
3637 parameters, we must save and restore it. */
3640 }
3641 #endif
3643 /* Push the args that need to be pushed. */
3645 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
3646 are to be pushed. */
3648 {
3656 {
3658 {
3659 /* If this is being stored into a pre-allocated, fixed-size,
3660 stack area, save any previous data at that location. */
3662 #ifdef ARGS_GROW_DOWNWARD
3663 /* stack_slot is negative, but we want to index stack_usage_map
3664 with positive values. */
3667 #else
3670 #endif
3673 /* Don't worry about things in the fixed argument area;
3674 it has already been saved. */
3678 i++;
3681 {
3682 /* We need to make a save area. */
3683 unsigned int size
3685 enum machine_mode save_mode
3687 rtx adr
3690 rtx stack_area
3694 {
3701 stack_area,
3703 BLOCK_OP_CALL_PARM);
3704 }
3705 else
3706 {
3710 }
3711 }
3712 }
3717 reg_parm_stack_space,
3720 /* Now mark the segment we just used. */
3725 NO_DEFER_POP;
3728 {
3729 rtx use;
3731 /* Indicate argument access so that alias.c knows that these
3732 values are live. */
3736 else
3737 /* When arguments are pushed, trying to tell alias.c where
3738 exactly this argument is won't work, because the
3739 auto-increment causes confusion. So we merely indicate
3740 that we access something with a known mode somewhere on
3741 the stack. */
3747 }
3748 }
3749 }
3751 /* If we pushed args in forward order, perform stack alignment
3752 after pushing the last arg. */
3759 else
3764 /* Now load any reg parms into their regs. */
3766 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
3767 are to be pushed. */
3769 {
3775 /* Handle calls that pass values in multiple non-contiguous
3776 locations. The PA64 has examples of this for library calls. */
3782 NO_DEFER_POP;
3783 }
3785 /* Any regs containing parms remain in use through the call. */
3787 {
3793 }
3795 /* Pass the function the address in which to return a structure value. */
3797 {
3801 NULL_RTX)));
3804 }
3806 /* Don't allow popping to be deferred, since then
3807 cse'ing of library calls could delete a call and leave the pop. */
3808 NO_DEFER_POP;
3812 /* Stack must be properly aligned now. */
3818 /* We pass the old value of inhibit_defer_pop + 1 to emit_call_1, which
3819 will set inhibit_defer_pop to that value. */
3820 /* The return type is needed to decide how many bytes the function pops.
3821 Signedness plays no role in that, so for simplicity, we pretend it's
3822 always signed. We also assume that the list of arguments passed has
3823 no impact, so we pretend it is unknown. */
3829 struct_value_size,
3831 valreg,
3834 /* For calls to `setjmp', etc., inform flow.c it should complain
3835 if nonvolatile values are live. For functions that cannot return,
3836 inform flow that control does not fall through. */
3839 {
3840 /* The barrier note must be emitted
3841 immediately after the CALL_INSN. Some ports emit more than
3842 just a CALL_INSN above, so we must search for it here. */
3846 {
3848 /* There was no CALL_INSN? */
3850 }
3853 }
3855 /* Now restore inhibit_defer_pop to its actual original value. */
3856 OK_DEFER_POP;
3858 /* If call is cse'able, make appropriate pair of reg-notes around it.
3859 Test valreg so we don't crash; may safely ignore `const'
3860 if return type is void. Disable for PARALLEL return values, because
3861 we have no way to move such values into a pseudo register. */
3863 {
3864 rtx insns;
3867 {
3871 }
3872 else
3873 {
3875 rtx temp;
3879 {
3884 }
3888 /* Construct an "equal form" for the value which mentions all the
3889 arguments in order as well as the function name. */
3902 note);
3907 }
3908 }
3911 /* Copy the value to the right place. */
3913 {
3915 {
3920 }
3922 {
3926 }
3929 else
3931 }
3934 {
3935 #ifdef REG_PARM_STACK_SPACE
3939 #endif
3941 /* If we saved any argument areas, restore them. */
3944 {
3955 BLOCK_OP_CALL_PARM);
3956 else
3958 }
3962 }
3969 }
3970 \f
3971 /* Output a library call to function FUN (a SYMBOL_REF rtx)
3972 (emitting the queue unless NO_QUEUE is nonzero),
3973 for a value of mode OUTMODE,
3974 with NARGS different arguments, passed as alternating rtx values
3975 and machine_modes to convert them to.
3977 FN_TYPE should be LCT_NORMAL for `normal' calls, LCT_CONST for `const'
3978 calls, LCT_PURE for `pure' calls, LCT_CONST_MAKE_BLOCK for `const' calls
3979 which should be enclosed in REG_LIBCALL/REG_RETVAL notes,
3980 LCT_PURE_MAKE_BLOCK for `purep' calls which should be enclosed in
3981 REG_LIBCALL/REG_RETVAL notes with extra (use (memory (scratch)),
3982 or other LCT_ value for other types of library calls. */
3984 void
3987 {
3993 }
3994 \f
3995 /* Like emit_library_call except that an extra argument, VALUE,
3996 comes second and says where to store the result.
3997 (If VALUE is zero, this function chooses a convenient way
3998 to return the value.
4000 This function returns an rtx for where the value is to be found.
4001 If VALUE is nonzero, VALUE is returned. */
4003 rtx
4007 {
4008 rtx result;
4017 }
4018 \f
4019 /* Store a single argument for a function call
4020 into the register or memory area where it must be passed.
4021 *ARG describes the argument value and where to pass it.
4023 ARGBLOCK is the address of the stack-block for all the arguments,
4024 or 0 on a machine where arguments are pushed individually.
4026 MAY_BE_ALLOCA nonzero says this could be a call to `alloca'
4027 so must be careful about how the stack is used.
4029 VARIABLE_SIZE nonzero says that this was a variable-sized outgoing
4030 argument stack. This is used if ACCUMULATE_OUTGOING_ARGS to indicate
4031 that we need not worry about saving and restoring the stack.
4033 FNDECL is the declaration of the function we are calling.
4035 Return nonzero if this arg should cause sibcall failure,
4036 zero otherwise. */
4038 static int
4041 {
4052 /* Push a new temporary level for any temporaries we make for
4053 this argument. */
4057 {
4058 /* If this is being stored into a pre-allocated, fixed-size, stack area,
4059 save any previous data at that location. */
4061 {
4062 #ifdef ARGS_GROW_DOWNWARD
4063 /* stack_slot is negative, but we want to index stack_usage_map
4064 with positive values. */
4067 else
4071 #else
4074 else
4078 #endif
4081 /* Don't worry about things in the fixed argument area;
4082 it has already been saved. */
4086 i++;
4089 {
4090 /* We need to make a save area. */
4097 {
4106 BLOCK_OP_CALL_PARM);
4107 }
4108 else
4109 {
4112 }
4113 }
4114 }
4115 }
4117 /* If this isn't going to be placed on both the stack and in registers,
4118 set up the register and number of words. */
4120 {
4123 else
4126 }
4128 /* Being passed entirely in a register. We shouldn't be called in
4129 this case. */
4132 /* If this arg needs special alignment, don't load the registers
4133 here. */
4137 /* If this is being passed partially in a register, we can't evaluate
4138 it directly into its stack slot. Otherwise, we can. */
4140 {
4141 /* stack_arg_under_construction is nonzero if a function argument is
4142 being evaluated directly into the outgoing argument list and
4143 expand_call must take special action to preserve the argument list
4144 if it is called recursively.
4146 For scalar function arguments stack_usage_map is sufficient to
4147 determine which stack slots must be saved and restored. Scalar
4148 arguments in general have pass_on_stack == 0.
4150 If this argument is initialized by a function which takes the
4151 address of the argument (a C++ constructor or a C function
4152 returning a BLKmode structure), then stack_usage_map is
4153 insufficient and expand_call must push the stack around the
4154 function call. Such arguments have pass_on_stack == 1.
4156 Note that it is always safe to set stack_arg_under_construction,
4157 but this generates suboptimal code if set when not needed. */
4160 stack_arg_under_construction++;
4163 (partial
4168 /* If we are promoting object (or for any other reason) the mode
4169 doesn't agree, convert the mode. */
4176 stack_arg_under_construction--;
4177 }
4179 /* Check for overlap with already clobbered argument area. */
4186 /* Don't allow anything left on stack from computation
4187 of argument to alloca. */
4192 /* If the value is already in the stack slot, we are done. */
4193 ;
4195 {
4198 /* Argument is a scalar, not entirely passed in registers.
4199 (If part is passed in registers, arg->partial says how much
4200 and emit_push_insn will take care of putting it there.)
4202 Push it, and if its size is less than the
4203 amount of space allocated to it,
4204 also bump stack pointer by the additional space.
4205 Note that in C the default argument promotions
4206 will prevent such mismatches. */
4209 /* Compute how much space the push instruction will push.
4210 On many machines, pushing a byte will advance the stack
4211 pointer by a halfword. */
4212 #ifdef PUSH_ROUNDING
4214 #endif
4217 /* Compute how much space the argument should get:
4218 round up to a multiple of the alignment for arguments. */
4224 /* This isn't already where we want it on the stack, so put it there.
4225 This can either be done with push or copy insns. */
4231 /* Unless this is a partially-in-register argument, the argument is now
4232 in the stack. */
4235 }
4236 else
4237 {
4238 /* BLKmode, at least partly to be pushed. */
4242 rtx size_rtx;
4244 /* Pushing a nonscalar.
4245 If part is passed in registers, PARTIAL says how much
4246 and emit_push_insn will take care of putting it there. */
4248 /* Round its size up to a multiple
4249 of the allocation unit for arguments. */
4252 {
4255 }
4256 else
4257 {
4258 /* PUSH_ROUNDING has no effect on us, because emit_push_insn
4259 for BLKmode is careful to avoid it. */
4265 }
4269 /* When an argument is padded down, the block is aligned to
4270 PARM_BOUNDARY, but the actual argument isn't. */
4272 {
4276 {
4279 }
4280 }
4283 {
4284 /* emit_push_insn might not work properly if arg->value and
4285 argblock + arg->locate.offset areas overlap. */
4292 current_function_internal_arg_pointer
4294 {
4298 /* expand_call should ensure this. */
4303 {
4306 }
4308 {
4311 }
4312 }
4313 }
4320 /* Unless this is a partially-in-register argument, the argument is now
4321 in the stack.
4323 ??? Unlike the case above, in which we want the actual
4324 address of the data, so that we can load it directly into a
4325 register, here we want the address of the stack slot, so that
4326 it's properly aligned for word-by-word copying or something
4327 like that. It's not clear that this is always correct. */
4330 }
4333 {
4335 arg->parallel_value
4338 }
4340 /* Mark all slots this store used. */
4346 /* Once we have pushed something, pops can't safely
4347 be deferred during the rest of the arguments. */
4348 NO_DEFER_POP;
4350 /* Free any temporary slots made in processing this argument. Show
4351 that we might have taken the address of something and pushed that
4352 as an operand. */
4358 }
4360 /* Nonzero if we do not know how to pass TYPE solely in registers. */
4362 bool
4364 tree type)
4365 {
4369 /* If the type has variable size... */
4373 /* If the type is marked as addressable (it is required
4374 to be constructed into the stack)... */
4379 }
4381 /* Another version of the TARGET_MUST_PASS_IN_STACK hook. This one
4382 takes trailing padding of a structure into account. */
4383 /* ??? Should be able to merge these two by examining BLOCK_REG_PADDING. */
4385 bool
4387 {
4391 /* If the type has variable size... */
4395 /* If the type is marked as addressable (it is required
4396 to be constructed into the stack)... */
4400 /* If the padding and mode of the type is such that a copy into
4401 a register would put it into the wrong part of the register. */
4409 }