| blob | a6a071a09f80f22d243eca2bdda980bc16953b54 |
1 /* Convert function calls to rtl insns, for GNU C compiler.
2 Copyright (C) 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002, 2003, 2004, 2005
4 Free Software Foundation, Inc.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 2, or (at your option) any later
11 version.
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING. If not, write to the Free
20 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
21 02111-1307, USA. */
45 /* Like PREFERRED_STACK_BOUNDARY but in units of bytes, not bits. */
46 #define STACK_BYTES (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT)
48 /* Data structure and subroutines used within expand_call. */
50 struct arg_data
51 {
52 /* Tree node for this argument. */
53 tree tree_value;
54 /* Mode for value; TYPE_MODE unless promoted. */
56 /* Current RTL value for argument, or 0 if it isn't precomputed. */
57 rtx value;
58 /* Initially-compute RTL value for argument; only for const functions. */
59 rtx initial_value;
60 /* Register to pass this argument in, 0 if passed on stack, or an
61 PARALLEL if the arg is to be copied into multiple non-contiguous
62 registers. */
63 rtx reg;
64 /* Register to pass this argument in when generating tail call sequence.
65 This is not the same register as for normal calls on machines with
66 register windows. */
67 rtx tail_call_reg;
68 /* If REG is a PARALLEL, this is a copy of VALUE pulled into the correct
69 form for emit_group_move. */
70 rtx parallel_value;
71 /* If REG was promoted from the actual mode of the argument expression,
72 indicates whether the promotion is sign- or zero-extended. */
74 /* Number of registers to use. 0 means put the whole arg in registers.
75 Also 0 if not passed in registers. */
77 /* Nonzero if argument must be passed on stack.
78 Note that some arguments may be passed on the stack
79 even though pass_on_stack is zero, just because FUNCTION_ARG says so.
80 pass_on_stack identifies arguments that *cannot* go in registers. */
82 /* Some fields packaged up for locate_and_pad_parm. */
84 /* Location on the stack at which parameter should be stored. The store
85 has already been done if STACK == VALUE. */
86 rtx stack;
87 /* Location on the stack of the start of this argument slot. This can
88 differ from STACK if this arg pads downward. This location is known
89 to be aligned to FUNCTION_ARG_BOUNDARY. */
90 rtx stack_slot;
91 /* Place that this stack area has been saved, if needed. */
92 rtx save_area;
93 /* If an argument's alignment does not permit direct copying into registers,
94 copy in smaller-sized pieces into pseudos. These are stored in a
95 block pointed to by this field. The next field says how many
96 word-sized pseudos we made. */
99 };
101 /* A vector of one char per byte of stack space. A byte if nonzero if
102 the corresponding stack location has been used.
103 This vector is used to prevent a function call within an argument from
104 clobbering any stack already set up. */
107 /* Size of STACK_USAGE_MAP. */
110 /* A bitmap of virtual-incoming stack space. Bit is set if the corresponding
111 stack location's tail call argument has been already stored into the stack.
112 This bitmap is used to prevent sibling call optimization if function tries
113 to use parent's incoming argument slots when they have been already
114 overwritten with tail call arguments. */
117 /* stack_arg_under_construction is nonzero when an argument may be
118 initialized with a constructor call (including a C function that
119 returns a BLKmode struct) and expand_call must take special action
120 to make sure the object being constructed does not overlap the
121 argument list for the constructor call. */
126 CUMULATIVE_ARGS *);
154 #ifdef REG_PARM_STACK_SPACE
157 #endif
158 \f
159 /* Force FUNEXP into a form suitable for the address of a CALL,
160 and return that as an rtx. Also load the static chain register
161 if FNDECL is a nested function.
163 CALL_FUSAGE points to a variable holding the prospective
164 CALL_INSN_FUNCTION_USAGE information. */
166 rtx
169 {
170 /* Make a valid memory address and copy constants through pseudo-regs,
171 but not for a constant address if -fno-function-cse. */
173 /* If we are using registers for parameters, force the
174 function address into a register now. */
179 {
180 #ifndef NO_FUNCTION_CSE
183 #endif
184 }
187 {
193 }
196 }
198 /* Generate instructions to call function FUNEXP,
199 and optionally pop the results.
200 The CALL_INSN is the first insn generated.
202 FNDECL is the declaration node of the function. This is given to the
203 macro RETURN_POPS_ARGS to determine whether this function pops its own args.
205 FUNTYPE is the data type of the function. This is given to the macro
206 RETURN_POPS_ARGS to determine whether this function pops its own args.
207 We used to allow an identifier for library functions, but that doesn't
208 work when the return type is an aggregate type and the calling convention
209 says that the pointer to this aggregate is to be popped by the callee.
211 STACK_SIZE is the number of bytes of arguments on the stack,
212 ROUNDED_STACK_SIZE is that number rounded up to
213 PREFERRED_STACK_BOUNDARY; zero if the size is variable. This is
214 both to put into the call insn and to generate explicit popping
215 code if necessary.
217 STRUCT_VALUE_SIZE is the number of bytes wanted in a structure value.
218 It is zero if this call doesn't want a structure value.
220 NEXT_ARG_REG is the rtx that results from executing
221 FUNCTION_ARG (args_so_far, VOIDmode, void_type_node, 1)
222 just after all the args have had their registers assigned.
223 This could be whatever you like, but normally it is the first
224 arg-register beyond those used for args in this call,
225 or 0 if all the arg-registers are used in this call.
226 It is passed on to `gen_call' so you can put this info in the call insn.
228 VALREG is a hard register in which a value is returned,
229 or 0 if the call does not return a value.
231 OLD_INHIBIT_DEFER_POP is the value that `inhibit_defer_pop' had before
232 the args to this call were processed.
233 We restore `inhibit_defer_pop' to that value.
235 CALL_FUSAGE is either empty or an EXPR_LIST of USE expressions that
236 denote registers used by the called function. */
238 static void
240 tree funtype ATTRIBUTE_UNUSED,
241 HOST_WIDE_INT stack_size ATTRIBUTE_UNUSED,
242 HOST_WIDE_INT rounded_stack_size,
243 HOST_WIDE_INT struct_value_size ATTRIBUTE_UNUSED,
247 {
249 rtx call_insn;
252 #if defined (HAVE_call) && defined (HAVE_call_value)
253 rtx struct_value_size_rtx;
255 #endif
257 #ifdef CALL_POPS_ARGS
259 #endif
261 /* Ensure address is valid. SYMBOL_REF is already valid, so no need,
262 and we don't want to load it into a register as an optimization,
263 because prepare_call_address already did it if it should be done. */
267 #if defined (HAVE_sibcall_pop) && defined (HAVE_sibcall_value_pop)
271 {
273 rtx pat;
275 /* If this subroutine pops its own args, record that in the call insn
276 if possible, for the sake of frame pointer elimination. */
282 n_pop);
283 else
289 }
290 else
291 #endif
293 #if defined (HAVE_call_pop) && defined (HAVE_call_value_pop)
294 /* If the target has "call" or "call_value" insns, then prefer them
295 if no arguments are actually popped. If the target does not have
296 "call" or "call_value" insns, then we must use the popping versions
297 even if the call has no arguments to pop. */
298 #if defined (HAVE_call) && defined (HAVE_call_value)
301 #else
303 #endif
304 {
306 rtx pat;
308 /* If this subroutine pops its own args, record that in the call insn
309 if possible, for the sake of frame pointer elimination. */
315 else
321 }
322 else
323 #endif
325 #if defined (HAVE_sibcall) && defined (HAVE_sibcall_value)
328 {
332 rounded_stack_size_rtx,
334 else
337 struct_value_size_rtx));
338 }
339 else
340 #endif
342 #if defined (HAVE_call) && defined (HAVE_call_value)
344 {
349 NULL_RTX));
350 else
353 struct_value_size_rtx));
354 }
355 else
356 #endif
359 /* Find the call we just emitted. */
362 /* Mark memory as used for "pure" function call. */
364 call_fusage
365 = gen_rtx_EXPR_LIST
369 call_fusage);
371 /* Put the register usage information there. */
374 /* If this is a const call, then set the insn's unchanging bit. */
378 /* If this call can't throw, attach a REG_EH_REGION reg note to that
379 effect. */
383 else
384 {
387 /* If rn < 0, then either (1) tree-ssa not used or (2) doesn't
388 throw, which we already took care of. */
393 }
400 {
404 }
408 /* Restore this now, so that we do defer pops for this call's args
409 if the context of the call as a whole permits. */
413 {
422 }
425 {
426 /* If returning from the subroutine does not automatically pop the args,
427 we need an instruction to pop them sooner or later.
428 Perhaps do it now; perhaps just record how much space to pop later.
430 If returning from the subroutine does pop the args, indicate that the
431 stack pointer will be changed. */
434 {
436 /* Just pretend we did the pop. */
441 else
443 }
444 }
445 /* When we accumulate outgoing args, we must avoid any stack manipulations.
446 Restore the stack pointer to its original value now. Usually
447 ACCUMULATE_OUTGOING_ARGS targets don't get here, but there are exceptions.
448 On i386 ACCUMULATE_OUTGOING_ARGS can be enabled on demand, and
449 popping variants of functions exist as well.
451 ??? We may optimize similar to defer_pop above, but it is
452 probably not worthwhile.
454 ??? It will be worthwhile to enable combine_stack_adjustments even for
455 such machines. */
458 }
460 /* Determine if the function identified by NAME and FNDECL is one with
461 special properties we wish to know about.
463 For example, if the function might return more than one time (setjmp), then
464 set RETURNS_TWICE to a nonzero value.
466 Similarly set 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 }
536 }
539 }
541 /* Return nonzero when FNDECL represents a call to setjmp. */
543 int
545 {
547 }
549 /* Return true when exp contains alloca call. */
550 bool
552 {
561 }
563 /* Detect flags (function attributes) from the function decl or type node. */
565 int
567 {
572 {
577 {
582 }
584 /* The function exp may have the `malloc' attribute. */
588 /* The function exp may have the `returns_twice' attribute. */
592 /* The function exp may have the `pure' attribute. */
606 }
613 /* Mark if the function returns with the stack pointer depressed. We
614 cannot consider it pure or constant in that case. */
616 {
619 }
622 }
624 /* Detect flags from a CALL_EXPR. */
626 int
628 {
634 else
635 {
639 else
641 }
644 }
646 /* Precompute all register parameters as described by ARGS, storing values
647 into fields within the ARGS array.
649 NUM_ACTUALS indicates the total number elements in the ARGS array.
651 Set REG_PARM_SEEN if we encounter a register parameter. */
653 static void
656 {
663 {
667 {
673 }
675 /* If the value is a non-legitimate constant, force it into a
676 pseudo now. TLS symbols sometimes need a call to resolve. */
681 /* If we are to promote the function arg to a wider mode,
682 do it now. */
690 /* If we're going to have to load the value by parts, pull the
691 parts into pseudos. The part extraction process can involve
692 non-trivial computation. */
694 {
699 }
701 /* If the value is expensive, and we are inside an appropriately
702 short loop, put the value into a pseudo and then put the pseudo
703 into the hard reg.
705 For small register classes, also do this if this call uses
706 register parameters. This is to avoid reload conflicts while
707 loading the parameters registers. */
717 }
718 }
720 #ifdef REG_PARM_STACK_SPACE
722 /* The argument list is the property of the called routine and it
723 may clobber it. If the fixed area has been used for previous
724 parameters, we must save and restore it. */
726 static rtx
727 save_fixed_argument_area (int reg_parm_stack_space, rtx argblock, int *low_to_save, int *high_to_save)
728 {
732 /* Compute the boundary of the area that needs to be saved, if any. */
734 #ifdef ARGS_GROW_DOWNWARD
736 #endif
742 {
746 rtx stack_area;
747 rtx save_area;
750 ;
758 /* If we don't have the required alignment, must do this
759 in BLKmode. */
764 #ifdef ARGS_GROW_DOWNWARD
766 #else
768 #endif
772 delta)));
776 {
780 }
781 else
782 {
785 }
788 }
791 }
793 static void
795 {
798 rtx stack_area;
800 #ifdef ARGS_GROW_DOWNWARD
802 #else
804 #endif
812 else
815 BLOCK_OP_CALL_PARM);
816 }
819 /* If any elements in ARGS refer to parameters that are to be passed in
820 registers, but not in memory, and whose alignment does not permit a
821 direct copy into registers. Copy the values into a group of pseudos
822 which we will later copy into the appropriate hard registers.
824 Pseudos for each unaligned argument will be stored into the array
825 args[argnum].aligned_regs. The caller is responsible for deallocating
826 the aligned_regs array if it is nonzero. */
828 static void
830 {
838 {
843 {
846 }
847 else
848 {
851 }
855 /* Structures smaller than a word are normally aligned to the
856 least significant byte. On a BYTES_BIG_ENDIAN machine,
857 this means we must skip the empty high order bytes when
858 calculating the bit offset. */
860 #ifdef BLOCK_REG_PADDING
864 #else
865 && BYTES_BIG_ENDIAN
866 #endif
867 )
871 {
880 /* There is no need to restrict this code to loading items
881 in TYPE_ALIGN sized hunks. The bitfield instructions can
882 load up entire word sized registers efficiently.
884 ??? This may not be needed anymore.
885 We use to emit a clobber here but that doesn't let later
886 passes optimize the instructions we emit. By storing 0 into
887 the register later passes know the first AND to zero out the
888 bitfield being set in the register is unnecessary. The store
889 of 0 will be deleted as will at least the first AND. */
895 word);
896 }
897 }
898 }
900 /* Fill in ARGS_SIZE and ARGS array based on the parameters found in
901 ACTPARMS.
903 NUM_ACTUALS is the total number of parameters.
905 N_NAMED_ARGS is the total number of named arguments.
907 FNDECL is the tree code for the target of this call (if known)
909 ARGS_SO_FAR holds state needed by the target to know where to place
910 the next argument.
912 REG_PARM_STACK_SPACE is the number of bytes of stack space reserved
913 for arguments which are passed in registers.
915 OLD_STACK_LEVEL is a pointer to an rtx which olds the old stack level
916 and may be modified by this routine.
918 OLD_PENDING_ADJ, MUST_PREALLOCATE and FLAGS are pointers to integer
919 flags which may may be modified by this routine.
921 MAY_TAILCALL is cleared if we encounter an invisible pass-by-reference
922 that requires allocation of stack space.
924 CALL_FROM_THUNK_P is true if this call is the jump from a thunk to
925 the thunked-to function. */
927 static void
938 {
939 /* 1 if scanning parms front to back, -1 if scanning back to front. */
942 /* Count arg position in order args appear. */
946 tree p;
951 /* In this loop, we consider args in the order they are written.
952 We fill up ARGS from the front or from the back if necessary
953 so that in any case the first arg to be pushed ends up at the front. */
956 {
958 /* In this case, must reverse order of args
959 so that we compute and push the last arg first. */
960 }
961 else
962 {
964 }
966 /* I counts args in order (to be) pushed; ARGPOS counts in order written. */
968 {
975 /* Replace erroneous argument with constant zero. */
979 /* If TYPE is a transparent union, pass things the way we would
980 pass the first field of the union. We have already verified that
981 the modes are the same. */
985 /* Decide where to pass this arg.
987 args[i].reg is nonzero if all or part is passed in registers.
989 args[i].partial is nonzero if part but not all is passed in registers,
990 and the exact value says how many bytes are passed in registers.
992 args[i].pass_on_stack is nonzero if the argument must at least be
993 computed on the stack. It may then be loaded back into registers
994 if args[i].reg is nonzero.
996 These decisions are driven by the FUNCTION_... macros and must agree
997 with those made by function.c. */
999 /* See if this argument should be passed by invisible reference. */
1002 {
1004 tree base;
1006 callee_copies
1010 /* If we're compiling a thunk, pass through invisible references
1011 instead of making a copy. */
1013 || (callee_copies
1017 {
1018 /* We can't use sibcalls if a callee-copied argument is
1019 stored in the current function's frame. */
1027 }
1028 else
1029 {
1030 /* We make a copy of the object and pass the address to the
1031 function being called. */
1032 rtx copy;
1038 STACK_CHECK_MAX_VAR_SIZE))))
1039 {
1040 /* This is a variable-sized object. Make space on the stack
1041 for it. */
1045 {
1049 }
1052 allocate_dynamic_stack_space
1055 }
1056 else
1063 else
1070 }
1071 }
1084 #ifdef FUNCTION_INCOMING_ARG
1085 /* If this is a sibling call and the machine has register windows, the
1086 register window has to be unwinded before calling the routine, so
1087 arguments have to go into the incoming registers. */
1090 #else
1092 #endif
1101 /* If FUNCTION_ARG returned a (parallel [(expr_list (nil) ...) ...]),
1102 it means that we are to pass this arg in the register(s) designated
1103 by the PARALLEL, but also to pass it in the stack. */
1108 /* If this is an addressable type, we must preallocate the stack
1109 since we must evaluate the object into its final location.
1111 If this is to be passed in both registers and the stack, it is simpler
1112 to preallocate. */
1117 /* If this is an addressable type, we cannot pre-evaluate it. Thus,
1118 we cannot consider this function call constant. */
1122 /* Compute the stack-size of this argument. */
1127 #ifdef STACK_PARMS_IN_REG_PARM_AREA
1129 #else
1131 #endif
1134 #ifdef BLOCK_REG_PADDING
1135 else
1136 /* The argument is passed entirely in registers. See at which
1137 end it should be padded. */
1141 #endif
1143 /* Update ARGS_SIZE, the total stack space for args so far. */
1149 /* Increment ARGS_SO_FAR, which has info about which arg-registers
1150 have been used, etc. */
1154 }
1155 }
1157 /* Update ARGS_SIZE to contain the total size for the argument block.
1158 Return the original constant component of the argument block's size.
1160 REG_PARM_STACK_SPACE holds the number of bytes of stack space reserved
1161 for arguments passed in registers. */
1163 static int
1167 {
1170 /* For accumulate outgoing args mode we don't need to align, since the frame
1171 will be already aligned. Align to STACK_BOUNDARY in order to prevent
1172 backends from generating misaligned frame sizes. */
1176 /* Compute the actual size of the argument block required. The variable
1177 and constant sizes must be combined, the size may have to be rounded,
1178 and there may be a minimum required size. */
1181 {
1187 {
1188 /* We don't handle this case yet. To handle it correctly we have
1189 to add the delta, round and subtract the delta.
1190 Currently no machine description requires this support. */
1193 }
1196 {
1197 args_size->var
1201 #ifndef OUTGOING_REG_PARM_STACK_SPACE
1202 /* The area corresponding to register parameters is not to count in
1203 the size of the block we need. So make the adjustment. */
1204 args_size->var
1207 #endif
1208 }
1209 }
1210 else
1211 {
1216 + stack_pointer_delta
1218 / preferred_stack_boundary
1223 reg_parm_stack_space);
1225 #ifndef OUTGOING_REG_PARM_STACK_SPACE
1227 #endif
1228 }
1230 }
1232 /* Precompute parameters as needed for a function call.
1234 FLAGS is mask of ECF_* constants.
1236 NUM_ACTUALS is the number of arguments.
1238 ARGS is an array containing information for each argument; this
1239 routine fills in the INITIAL_VALUE and VALUE fields for each
1240 precomputed argument. */
1242 static void
1244 {
1247 /* If this is a libcall, then precompute all arguments so that we do not
1248 get extraneous instructions emitted as part of the libcall sequence. */
1253 {
1256 /* If this is an addressable type, we cannot pre-evaluate it. */
1264 {
1268 #if defined(PROMOTE_FUNCTION_MODE) && !defined(PROMOTE_MODE)
1269 /* CSE will replace this only if it contains args[i].value
1270 pseudo, so convert it down to the declared mode using
1271 a SUBREG. */
1274 {
1280 }
1281 #endif
1282 }
1283 }
1284 }
1286 /* Given the current state of MUST_PREALLOCATE and information about
1287 arguments to a function call in NUM_ACTUALS, ARGS and ARGS_SIZE,
1288 compute and return the final value for MUST_PREALLOCATE. */
1290 static int
1291 finalize_must_preallocate (int must_preallocate, int num_actuals, struct arg_data *args, struct args_size *args_size)
1292 {
1293 /* See if we have or want to preallocate stack space.
1295 If we would have to push a partially-in-regs parm
1296 before other stack parms, preallocate stack space instead.
1298 If the size of some parm is not a multiple of the required stack
1299 alignment, we must preallocate.
1301 If the total size of arguments that would otherwise create a copy in
1302 a temporary (such as a CALL) is more than half the total argument list
1303 size, preallocation is faster.
1305 Another reason to preallocate is if we have a machine (like the m88k)
1306 where stack alignment is required to be maintained between every
1307 pair of insns, not just when the call is made. However, we assume here
1308 that such machines either do not have push insns (and hence preallocation
1309 would occur anyway) or the problem is taken care of with
1310 PUSH_ROUNDING. */
1313 {
1319 {
1330 copy_to_evaluate_size
1332 }
1337 }
1339 }
1341 /* If we preallocated stack space, compute the address of each argument
1342 and store it into the ARGS array.
1344 We need not ensure it is a valid memory address here; it will be
1345 validized when it is used.
1347 ARGBLOCK is an rtx for the address of the outgoing arguments. */
1349 static void
1351 {
1353 {
1361 {
1364 rtx addr;
1367 /* Skip this parm if it will not be passed on the stack. */
1373 else
1385 {
1388 }
1393 else
1402 /* Function incoming arguments may overlap with sibling call
1403 outgoing arguments and we cannot allow reordering of reads
1404 from function arguments with stores to outgoing arguments
1405 of sibling calls. */
1408 }
1409 }
1410 }
1412 /* Given a FNDECL and EXP, return an rtx suitable for use as a target address
1413 in a call instruction.
1415 FNDECL is the tree node for the target function. For an indirect call
1416 FNDECL will be NULL_TREE.
1418 ADDR is the operand 0 of CALL_EXPR for this call. */
1420 static rtx
1422 {
1423 rtx funexp;
1425 /* Get the function to call, in the form of RTL. */
1427 {
1428 /* If this is the first use of the function, see if we need to
1429 make an external definition for it. */
1431 {
1434 }
1436 /* Get a SYMBOL_REF rtx for the function address. */
1438 }
1439 else
1440 /* Generate an rtx (probably a pseudo-register) for the address. */
1441 {
1445 }
1447 }
1449 /* Do the register loads required for any wholly-register parms or any
1450 parms which are passed both on the stack and in a register. Their
1451 expressions were already evaluated.
1453 Mark all register-parms as living through the call, putting these USE
1454 insns in the CALL_INSN_FUNCTION_USAGE field.
1456 When IS_SIBCALL, perform the check_sibcall_overlap_argument_overlap
1457 checking, setting *SIBCALL_FAILURE if appropriate. */
1459 static void
1463 {
1467 {
1471 {
1476 /* Set to non-negative if must move a word at a time, even if just
1477 one word (e.g, partial == 1 && mode == DFmode). Set to -1 if
1478 we just use a normal move insn. This value can be zero if the
1479 argument is a zero size structure with no fields. */
1482 ;
1484 {
1487 }
1489 {
1492 }
1493 else
1496 /* Handle calls that pass values in multiple non-contiguous
1497 locations. The Irix 6 ABI has examples of this. */
1502 /* If simple case, just do move. If normal partial, store_one_arg
1503 has already loaded the register for us. In all other cases,
1504 load the register(s) from memory. */
1507 {
1509 #ifdef BLOCK_REG_PADDING
1510 /* Handle case where we have a value that needs shifting
1511 up to the msb. eg. a QImode value and we're padding
1512 upward on a BYTES_BIG_ENDIAN machine. */
1516 {
1517 rtx x;
1520 /* Assigning REG here rather than a temp makes CALL_FUSAGE
1521 report the whole reg as used. Strictly speaking, the
1522 call only uses SIZE bytes at the msb end, but it doesn't
1523 seem worth generating rtl to say that. */
1530 }
1531 #endif
1532 }
1534 /* If we have pre-computed the values to put in the registers in
1535 the case of non-aligned structures, copy them in now. */
1543 {
1546 /* Handle a BLKmode that needs shifting. */
1548 #ifdef BLOCK_REG_PADDING
1550 #else
1551 && BYTES_BIG_ENDIAN
1552 #endif
1553 )
1554 {
1568 }
1569 else
1571 }
1573 /* When a parameter is a block, and perhaps in other cases, it is
1574 possible that it did a load from an argument slot that was
1575 already clobbered. */
1580 /* Handle calls that pass values in multiple non-contiguous
1581 locations. The Irix 6 ABI has examples of this. */
1588 }
1589 }
1590 }
1592 /* We need to pop PENDING_STACK_ADJUST bytes. But, if the arguments
1593 wouldn't fill up an even multiple of PREFERRED_UNIT_STACK_BOUNDARY
1594 bytes, then we would need to push some additional bytes to pad the
1595 arguments. So, we compute an adjust to the stack pointer for an
1596 amount that will leave the stack under-aligned by UNADJUSTED_ARGS_SIZE
1597 bytes. Then, when the arguments are pushed the stack will be perfectly
1598 aligned. ARGS_SIZE->CONSTANT is set to the number of bytes that should
1599 be popped after the call. Returns the adjustment. */
1601 static int
1605 {
1606 /* The number of bytes to pop so that the stack will be
1607 under-aligned by UNADJUSTED_ARGS_SIZE bytes. */
1608 HOST_WIDE_INT adjustment;
1609 /* The alignment of the stack after the arguments are pushed, if we
1610 just pushed the arguments without adjust the stack here. */
1613 unadjusted_alignment
1617 /* We want to get rid of as many of the PENDING_STACK_ADJUST bytes
1618 as possible -- leaving just enough left to cancel out the
1619 UNADJUSTED_ALIGNMENT. In other words, we want to ensure that the
1620 PENDING_STACK_ADJUST is non-negative, and congruent to
1621 -UNADJUSTED_ALIGNMENT modulo the PREFERRED_UNIT_STACK_BOUNDARY. */
1623 /* Begin by trying to pop all the bytes. */
1624 unadjusted_alignment
1625 = (unadjusted_alignment
1628 /* Push enough additional bytes that the stack will be aligned
1629 after the arguments are pushed. */
1631 {
1634 else
1636 }
1638 /* Now, sets ARGS_SIZE->CONSTANT so that we pop the right number of
1639 bytes after the call. The right number is the entire
1640 PENDING_STACK_ADJUST less our ADJUSTMENT plus the amount required
1641 by the arguments in the first place. */
1642 args_size->constant
1646 }
1648 /* Scan X expression if it does not dereference any argument slots
1649 we already clobbered by tail call arguments (as noted in stored_args_map
1650 bitmap).
1651 Return nonzero if X expression dereferences such argument slots,
1652 zero otherwise. */
1654 static int
1656 {
1657 RTX_CODE code;
1668 {
1673 current_function_internal_arg_pointer
1676 else
1679 #ifdef ARGS_GROW_DOWNWARD
1681 #endif
1689 }
1691 /* Scan all subexpressions. */
1694 {
1696 {
1699 }
1701 {
1705 }
1706 }
1708 }
1710 /* Scan sequence after INSN if it does not dereference any argument slots
1711 we already clobbered by tail call arguments (as noted in stored_args_map
1712 bitmap). If MARK_STORED_ARGS_MAP, add stack slots for ARG to
1713 stored_args_map bitmap afterwards (when ARG is a register MARK_STORED_ARGS_MAP
1714 should be 0). Return nonzero if sequence after INSN dereferences such argument
1715 slots, zero otherwise. */
1717 static int
1719 {
1724 else
1733 {
1734 #ifdef ARGS_GROW_DOWNWARD
1736 #else
1738 #endif
1742 }
1744 }
1746 /* Given that a function returns a value of mode MODE at the most
1747 significant end of hard register VALUE, shift VALUE left or right
1748 as specified by LEFT_P. Return true if some action was needed. */
1750 bool
1752 {
1753 HOST_WIDE_INT shift;
1760 /* Use ashr rather than lshr for right shifts. This is for the benefit
1761 of the MIPS port, which requires SImode values to be sign-extended
1762 when stored in 64-bit registers. */
1767 }
1769 /* Remove all REG_EQUIV notes found in the insn chain. */
1771 static void
1773 {
1774 rtx insn;
1777 {
1779 {
1782 {
1783 /* Remove the note and keep looking at the notes for
1784 this insn. */
1787 }
1789 }
1790 }
1791 }
1793 /* Generate all the code for a function call
1794 and return an rtx for its value.
1795 Store the value in TARGET (specified as an rtx) if convenient.
1796 If the value is stored in TARGET then TARGET is returned.
1797 If IGNORE is nonzero, then we ignore the value of the function call. */
1799 rtx
1801 {
1802 /* Nonzero if we are currently expanding a call. */
1805 /* List of actual parameters. */
1807 /* RTX for the function to be called. */
1808 rtx funexp;
1809 /* Sequence of insns to perform a normal "call". */
1811 /* Sequence of insns to perform a tail "call". */
1813 /* Data type of the function. */
1814 tree funtype;
1815 tree type_arg_types;
1816 /* Declaration of the function being called,
1817 or 0 if the function is computed (not known by name). */
1819 /* The type of the function being called. */
1820 tree fntype;
1824 /* Register in which non-BLKmode value will be returned,
1825 or 0 if no value or if value is BLKmode. */
1826 rtx valreg;
1827 /* Address where we should return a BLKmode value;
1828 0 if value not BLKmode. */
1830 /* Nonzero if that address is being passed by treating it as
1831 an extra, implicit first parameter. Otherwise,
1832 it is passed by being copied directly into struct_value_rtx. */
1834 /* Size of aggregate value wanted, or zero if none wanted
1835 or if we are using the non-reentrant PCC calling convention
1836 or expecting the value in registers. */
1838 /* Nonzero if called function returns an aggregate in memory PCC style,
1839 by returning the address of where to find it. */
1843 /* Number of actual parameters in this call, including struct value addr. */
1845 /* Number of named args. Args after this are anonymous ones
1846 and they must all go on the stack. */
1849 /* Vector of information about each argument.
1850 Arguments are numbered in the order they will be pushed,
1851 not the order they are written. */
1854 /* Total size in bytes of all the stack-parms scanned so far. */
1857 /* Size of arguments before any adjustments (such as rounding). */
1859 /* Data on reg parms scanned so far. */
1860 CUMULATIVE_ARGS args_so_far;
1861 /* Nonzero if a reg parm has been scanned. */
1863 /* Nonzero if this is an indirect function call. */
1865 /* Nonzero if we must avoid push-insns in the args for this call.
1866 If stack space is allocated for register parameters, but not by the
1867 caller, then it is preallocated in the fixed part of the stack frame.
1868 So the entire argument block must then be preallocated (i.e., we
1869 ignore PUSH_ROUNDING in that case). */
1873 /* Size of the stack reserved for parameter registers. */
1876 /* Address of space preallocated for stack parms
1877 (on machines that lack push insns), or 0 if space not preallocated. */
1880 /* Mask of ECF_ flags. */
1882 #ifdef REG_PARM_STACK_SPACE
1883 /* Define the boundary of the register parm stack space that needs to be
1884 saved, if any. */
1887 #endif
1894 /* State variables to track stack modifications. */
1900 /* Some stack pointer alterations we make are performed via
1901 allocate_dynamic_stack_space. This modifies the stack_pointer_delta,
1902 which we then also need to save/restore along the way. */
1905 rtx call_fusage;
1909 /* The alignment of the stack, in bits. */
1911 /* The alignment of the stack, in bytes. */
1913 /* The static chain value to use for this call. */
1914 rtx static_chain_value;
1915 /* See if this is "nothrow" function call. */
1919 /* See if we can find a DECL-node for the actual function, and get the
1920 function attributes (flags) from the function decl or type node. */
1923 {
1926 }
1927 else
1928 {
1931 }
1935 /* Warn if this value is an aggregate type,
1936 regardless of which calling convention we are using for it. */
1940 /* If the result of a pure or const function call is ignored (or void),
1941 and none of its arguments are volatile, we can avoid expanding the
1942 call and just evaluate the arguments for side-effects. */
1946 {
1948 tree arg;
1952 {
1955 }
1958 {
1963 }
1964 }
1966 #ifdef REG_PARM_STACK_SPACE
1968 #endif
1970 #ifndef OUTGOING_REG_PARM_STACK_SPACE
1973 #endif
1975 /* Set up a place to return a structure. */
1977 /* Cater to broken compilers. */
1979 {
1980 /* This call returns a big structure. */
1983 #ifdef PCC_STATIC_STRUCT_RETURN
1984 {
1986 }
1988 {
1992 {
1993 /* The structure value address arg is already in actparms.
1994 Pull it out. It might be nice to just leave it there, but
1995 we need to set structure_value_addr. */
2000 }
2003 else
2004 {
2005 /* For variable-sized objects, we must be called with a target
2006 specified. If we were to allocate space on the stack here,
2007 we would have no way of knowing when to free it. */
2013 }
2014 }
2016 }
2018 /* Figure out the amount to which the stack should be aligned. */
2021 {
2025 }
2027 /* Operand 0 is a pointer-to-function; get the type of the function. */
2032 /* Munge the tree to split complex arguments into their imaginary
2033 and real parts. */
2035 {
2038 }
2039 else
2045 /* If struct_value_rtx is 0, it means pass the address
2046 as if it were an extra parameter. */
2048 {
2049 /* If structure_value_addr is a REG other than
2050 virtual_outgoing_args_rtx, we can use always use it. If it
2051 is not a REG, we must always copy it into a register.
2052 If it is virtual_outgoing_args_rtx, we must copy it to another
2053 register in some cases. */
2055 || (ACCUMULATE_OUTGOING_ARGS
2056 && stack_arg_under_construction
2062 actparms
2065 temp),
2066 actparms);
2068 }
2070 /* Count the arguments and set NUM_ACTUALS. */
2072 num_actuals++;
2074 /* Compute number of named args.
2075 First, do a raw count of the args for INIT_CUMULATIVE_ARGS. */
2078 n_named_args
2080 /* Count the struct value address, if it is passed as a parm. */
2082 else
2083 /* If we know nothing, treat all args as named. */
2086 /* Start updating where the next arg would go.
2088 On some machines (such as the PA) indirect calls have a different
2089 calling convention than normal calls. The fourth argument in
2090 INIT_CUMULATIVE_ARGS tells the backend if this is an indirect call
2091 or not. */
2094 /* Now possibly adjust the number of named args.
2095 Normally, don't include the last named arg if anonymous args follow.
2096 We do include the last named arg if
2097 targetm.calls.strict_argument_naming() returns nonzero.
2098 (If no anonymous args follow, the result of list_length is actually
2099 one too large. This is harmless.)
2101 If targetm.calls.pretend_outgoing_varargs_named() returns
2102 nonzero, and targetm.calls.strict_argument_naming() returns zero,
2103 this machine will be able to place unnamed args that were passed
2104 in registers into the stack. So treat all args as named. This
2105 allows the insns emitting for a specific argument list to be
2106 independent of the function declaration.
2108 If targetm.calls.pretend_outgoing_varargs_named() returns zero,
2109 we do not have any reliable way to pass unnamed args in
2110 registers, so we must force them into memory. */
2114 ;
2117 /* Don't include the last named arg. */
2119 else
2120 /* Treat all args as named. */
2123 /* Make a vector to hold all the information about each arg. */
2127 /* Build up entries in the ARGS array, compute the size of the
2128 arguments into ARGS_SIZE, etc. */
2137 {
2138 /* If this function requires a variable-sized argument list, don't
2139 try to make a cse'able block for this call. We may be able to
2140 do this eventually, but it is too complicated to keep track of
2141 what insns go in the cse'able block and which don't. */
2145 }
2147 /* Now make final decision about preallocating stack space. */
2152 /* If the structure value address will reference the stack pointer, we
2153 must stabilize it. We don't need to do this if we know that we are
2154 not going to adjust the stack pointer in processing this call. */
2159 structure_value_addr))
2164 /* Tail calls can make things harder to debug, and we've traditionally
2165 pushed these optimizations into -O2. Don't try if we're already
2166 expanding a call, as that means we're an argument. Don't try if
2167 there's cleanups, as we know there's code to follow the call. */
2170 || !flag_optimize_sibling_calls
2175 /* Rest of purposes for tail call optimizations to fail. */
2177 #ifdef HAVE_sibcall_epilogue
2178 !HAVE_sibcall_epilogue
2179 #else
2180 1
2181 #endif
2182 || !try_tail_call
2183 /* Doing sibling call optimization needs some work, since
2184 structure_value_addr can be allocated on the stack.
2185 It does not seem worth the effort since few optimizable
2186 sibling calls will return a structure. */
2188 /* Check whether the target is able to optimize the call
2189 into a sibcall. */
2191 /* Functions that do not return exactly once may not be sibcall
2192 optimized. */
2195 /* If the called function is nested in the current one, it might access
2196 some of the caller's arguments, but could clobber them beforehand if
2197 the argument areas are shared. */
2199 /* If this function requires more stack slots than the current
2200 function, we cannot change it into a sibling call. */
2202 /* If the callee pops its own arguments, then it must pop exactly
2203 the same number of arguments as the current function. */
2207 current_function_args_size))
2211 /* Ensure current function's preferred stack boundary is at least
2212 what we need. We don't have to increase alignment for recursive
2213 functions. */
2222 /* We want to make two insn chains; one for a sibling call, the other
2223 for a normal call. We will select one of the two chains after
2224 initial RTL generation is complete. */
2226 {
2228 /* We want to emit any pending stack adjustments before the tail
2229 recursion "call". That way we know any adjustment after the tail
2230 recursion call can be ignored if we indeed use the tail
2231 call expansion. */
2234 rtx insns;
2238 {
2239 /* State variables we need to save and restore between
2240 iterations. */
2243 }
2246 else
2249 /* Other state variables that we must reinitialize each time
2250 through the loop (that are not initialized by the loop itself). */
2254 /* Start a new sequence for the normal call case.
2256 From this point on, if the sibling call fails, we want to set
2257 sibcall_failure instead of continuing the loop. */
2260 /* Don't let pending stack adjusts add up to too much.
2261 Also, do all pending adjustments now if there is any chance
2262 this might be a call to alloca or if we are expanding a sibling
2263 call sequence or if we are calling a function that is to return
2264 with stack pointer depressed. */
2271 /* When calling a const function, we must pop the stack args right away,
2272 so that the pop is deleted or moved with the call. */
2274 NO_DEFER_POP;
2276 /* Precompute any arguments as needed. */
2280 /* Now we are about to start emitting insns that can be deleted
2281 if a libcall is deleted. */
2286 /* Compute the actual size of the argument block required. The variable
2287 and constant sizes must be combined, the size may have to be rounded,
2288 and there may be a minimum required size. When generating a sibcall
2289 pattern, do not round up, since we'll be re-using whatever space our
2290 caller provided. */
2291 unadjusted_args_size
2299 /* The argument block when performing a sibling call is the
2300 incoming argument block. */
2302 {
2304 argblock
2305 #ifdef STACK_GROWS_DOWNWARD
2307 #else
2309 #endif
2312 }
2314 /* If we have no actual push instructions, or shouldn't use them,
2315 make space for all args right now. */
2317 {
2319 {
2324 /* stack_arg_under_construction says whether a stack arg is
2325 being constructed at the old stack level. Pushing the stack
2326 gets a clean outgoing argument block. */
2329 }
2331 }
2332 else
2333 {
2334 /* Note that we must go through the motions of allocating an argument
2335 block even if the size is zero because we may be storing args
2336 in the area reserved for register arguments, which may be part of
2337 the stack frame. */
2341 /* Store the maximum argument space used. It will be pushed by
2342 the prologue (if ACCUMULATE_OUTGOING_ARGS, or stack overflow
2343 checking). */
2349 {
2351 {
2352 /* Since the stack pointer will never be pushed, it is
2353 possible for the evaluation of a parm to clobber
2354 something we have already written to the stack.
2355 Since most function calls on RISC machines do not use
2356 the stack, this is uncommon, but must work correctly.
2358 Therefore, we save any area of the stack that was already
2359 written and that we are using. Here we set up to do this
2360 by making a new stack usage map from the old one. The
2361 actual save will be done by store_one_arg.
2363 Another approach might be to try to reorder the argument
2364 evaluations to avoid this conflicting stack usage. */
2366 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2367 /* Since we will be writing into the entire argument area,
2368 the map must be allocated for its entire size, not just
2369 the part that is the responsibility of the caller. */
2371 #endif
2373 #ifdef ARGS_GROW_DOWNWARD
2376 #else
2378 needed);
2379 #endif
2384 initial_highest_arg_in_use);
2388 (highest_outgoing_arg_in_use
2392 /* The address of the outgoing argument list must not be
2393 copied to a register here, because argblock would be left
2394 pointing to the wrong place after the call to
2395 allocate_dynamic_stack_space below. */
2398 }
2399 else
2400 {
2402 {
2403 /* Try to reuse some or all of the pending_stack_adjust
2404 to get this space. */
2405 needed
2406 = (combine_pending_stack_adjustment_and_call
2409 preferred_unit_stack_boundary));
2411 /* combine_pending_stack_adjustment_and_call computes
2412 an adjustment before the arguments are allocated.
2413 Account for them and see whether or not the stack
2414 needs to go up or down. */
2418 {
2419 /* We're releasing stack space. */
2420 /* ??? We can avoid any adjustment at all if we're
2421 already aligned. FIXME. */
2425 }
2426 else
2427 /* We need to allocate space. We'll do that in
2428 push_block below. */
2430 }
2432 /* Special case this because overhead of `push_block' in
2433 this case is non-trivial. */
2436 else
2437 {
2439 #ifdef ARGS_GROW_DOWNWARD
2441 #endif
2442 }
2444 /* We only really need to call `copy_to_reg' in the case
2445 where push insns are going to be used to pass ARGBLOCK
2446 to a function call in ARGS. In that case, the stack
2447 pointer changes value from the allocation point to the
2448 call point, and hence the value of
2449 VIRTUAL_OUTGOING_ARGS_RTX changes as well. But might
2450 as well always do it. */
2452 }
2453 }
2454 }
2457 {
2458 /* The save/restore code in store_one_arg handles all
2459 cases except one: a constructor call (including a C
2460 function returning a BLKmode struct) to initialize
2461 an argument. */
2463 {
2464 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2467 #else
2469 #endif
2471 {
2473 NULL_RTX);
2477 /* stack_arg_under_construction says whether a stack
2478 arg is being constructed at the old stack level.
2479 Pushing the stack gets a clean outgoing argument
2480 block. */
2481 old_stack_arg_under_construction
2484 /* Make a new map for the new argument list. */
2488 }
2490 BITS_PER_UNIT);
2491 }
2493 /* If argument evaluation might modify the stack pointer,
2494 copy the address of the argument list to a register. */
2497 {
2500 }
2501 }
2505 /* If we push args individually in reverse order, perform stack alignment
2506 before the first push (the last arg). */
2509 {
2510 /* When the stack adjustment is pending, we get better code
2511 by combining the adjustments. */
2515 {
2516 pending_stack_adjust
2517 = (combine_pending_stack_adjustment_and_call
2520 preferred_unit_stack_boundary));
2522 }
2526 }
2527 /* Now that the stack is properly aligned, pops can't safely
2528 be deferred during the evaluation of the arguments. */
2529 NO_DEFER_POP;
2533 /* Figure out the register where the value, if any, will come back. */
2537 {
2541 else
2543 }
2545 /* Precompute all register parameters. It isn't safe to compute anything
2546 once we have started filling any specific hard regs. */
2552 else
2555 #ifdef REG_PARM_STACK_SPACE
2556 /* Save the fixed argument area if it's part of the caller's frame and
2557 is clobbered by argument setup for this call. */
2561 #endif
2563 /* Now store (and compute if necessary) all non-register parms.
2564 These come before register parms, since they can require block-moves,
2565 which could clobber the registers used for register parms.
2566 Parms which have partial registers are not stored here,
2567 but we do preallocate space here if they want that. */
2571 {
2576 reg_parm_stack_space)
2588 call_fusage);
2589 }
2591 /* If we have a parm that is passed in registers but not in memory
2592 and whose alignment does not permit a direct copy into registers,
2593 make a group of pseudos that correspond to each register that we
2594 will later fill. */
2598 /* Now store any partially-in-registers parm.
2599 This is the last place a block-move can happen. */
2603 {
2608 reg_parm_stack_space)
2613 }
2615 /* If we pushed args in forward order, perform stack alignment
2616 after pushing the last arg. */
2621 /* If register arguments require space on the stack and stack space
2622 was not preallocated, allocate stack space here for arguments
2623 passed in registers. */
2624 #ifdef OUTGOING_REG_PARM_STACK_SPACE
2628 #endif
2630 /* Pass the function the address in which to return a
2631 structure value. */
2633 {
2634 structure_value_addr
2639 NULL_RTX)));
2643 }
2651 /* Save a pointer to the last insn before the call, so that we can
2652 later safely search backwards to find the CALL_INSN. */
2655 /* Set up next argument register. For sibling calls on machines
2656 with register windows this should be the incoming register. */
2657 #ifdef FUNCTION_INCOMING_ARG
2661 else
2662 #endif
2666 /* All arguments and registers used for the call must be set up by
2667 now! */
2669 /* Stack must be properly aligned now. */
2673 /* Generate the actual call instruction. */
2679 /* If a non-BLKmode value is returned at the most significant end
2680 of a register, shift the register right by the appropriate amount
2681 and update VALREG accordingly. BLKmode values are handled by the
2682 group load/store machinery below. */
2684 && !pcc_struct_value
2687 {
2691 }
2693 /* If call is cse'able, make appropriate pair of reg-notes around it.
2694 Test valreg so we don't crash; may safely ignore `const'
2695 if return type is void. Disable for PARALLEL return values, because
2696 we have no way to move such values into a pseudo register. */
2698 {
2699 rtx insns;
2700 rtx insn;
2705 /* Expansion of block moves possibly introduced a loop that may
2706 not appear inside libcall block. */
2712 {
2715 }
2716 else
2717 {
2721 /* Mark the return value as a pointer if needed. */
2728 && fndecl
2736 else
2737 {
2738 /* Construct an "equal form" for the value which
2739 mentions all the arguments in order as well as
2740 the function name. */
2751 note);
2752 }
2756 }
2757 }
2759 {
2763 /* The return value from a malloc-like function is a pointer. */
2769 /* The return value from a malloc-like function can not alias
2770 anything else. */
2775 /* Write out the sequence. */
2780 }
2782 /* For calls to `setjmp', etc., inform flow.c it should complain
2783 if nonvolatile values are live. For functions that cannot return,
2784 inform flow that control does not fall through. */
2787 {
2788 /* The barrier must be emitted
2789 immediately after the CALL_INSN. Some ports emit more
2790 than just a CALL_INSN above, so we must search for it here. */
2794 {
2796 /* There was no CALL_INSN? */
2798 }
2802 /* Stack adjustments after a noreturn call are dead code.
2803 However when NO_DEFER_POP is in effect, we must preserve
2804 stack_pointer_delta. */
2806 {
2809 }
2810 }
2812 /* If value type not void, return an rtx for the value. */
2818 {
2820 {
2821 target
2824 structure_value_addr));
2826 }
2827 }
2829 {
2830 /* This is the special C++ case where we need to
2831 know what the true target was. We take care to
2832 never use this value more than once in one expression. */
2836 }
2837 /* Handle calls that return values in multiple non-contiguous locations.
2838 The Irix 6 ABI has examples of this. */
2840 {
2842 {
2843 /* This will only be assigned once, so it can be readonly. */
2849 }
2855 /* We can not support sibling calls for this case. */
2857 }
2861 {
2862 /* TARGET and VALREG cannot be equal at this point because the
2863 latter would not have REG_FUNCTION_VALUE_P true, while the
2864 former would if it were referring to the same register.
2866 If they refer to the same register, this move will be a no-op,
2867 except when function inlining is being done. */
2870 /* If we are setting a MEM, this code must be executed. Since it is
2871 emitted after the call insn, sibcall optimization cannot be
2872 performed in that case. */
2875 }
2877 {
2880 /* We can not support sibling calls for this case. */
2882 }
2883 else
2887 {
2888 /* If we promoted this return value, make the proper SUBREG.
2889 TARGET might be const0_rtx here, so be careful. */
2893 {
2900 /* If we don't promote as expected, something is wrong. */
2906 {
2913 }
2917 }
2918 }
2920 /* If size of args is variable or this was a constructor call for a stack
2921 argument, restore saved stack-pointer value. */
2924 {
2933 }
2935 {
2936 #ifdef REG_PARM_STACK_SPACE
2940 #endif
2942 /* If we saved any argument areas, restore them. */
2945 {
2947 rtx stack_area
2954 else
2957 BLOCK_OP_CALL_PARM);
2958 }
2962 }
2964 /* If this was alloca, record the new stack level for nonlocal gotos.
2965 Check for the handler slots since we might not have a save area
2966 for non-local gotos. */
2971 /* Free up storage we no longer need. */
2980 {
2983 /* Restore the pending stack adjustment now that we have
2984 finished generating the sibling call sequence. */
2989 /* Prepare arg structure for next iteration. */
2991 {
2995 }
2998 }
2999 else
3000 {
3003 /* Verify that we've deallocated all the stack we used. */
3005 || (old_stack_allocated
3007 }
3009 /* If something prevents making this a sibling call,
3010 zero out the sequence. */
3013 else
3015 }
3017 /* If tail call production succeeded, we need to remove REG_EQUIV notes on
3018 arguments too, as argument area is now clobbered by the call. */
3020 {
3023 }
3024 else
3027 currently_expanding_call--;
3029 /* If this function returns with the stack pointer depressed, ensure
3030 this block saves and restores the stack pointer, show it was
3031 changed, and adjust for any outgoing arg space. */
3033 {
3037 }
3040 }
3042 /* A sibling call sequence invalidates any REG_EQUIV notes made for
3043 this function's incoming arguments.
3045 At the start of RTL generation we know the only REG_EQUIV notes
3046 in the rtl chain are those for incoming arguments, so we can safely
3047 flush any REG_EQUIV note.
3049 This is (slight) overkill. We could keep track of the highest
3050 argument we clobber and be more selective in removing notes, but it
3051 does not seem to be worth the effort. */
3052 void
3054 {
3056 }
3058 /* Traverse an argument list in VALUES and expand all complex
3059 arguments into their components. */
3060 static tree
3062 {
3063 tree p;
3065 /* Before allocating memory, check for the common case of no complex. */
3067 {
3072 }
3075 found:
3079 {
3081 tree complex_type;
3089 {
3090 tree subtype;
3104 /* Skip the newly created node. */
3106 }
3107 }
3110 }
3112 /* Traverse a list of TYPES and expand all complex types into their
3113 components. */
3114 static tree
3116 {
3117 tree p;
3119 /* Before allocating memory, check for the common case of no complex. */
3121 {
3126 }
3129 found:
3133 {
3138 {
3141 /* Rewrite complex type with component type. */
3145 /* Add another component type for the imaginary part. */
3150 /* Skip the newly created node. */
3152 }
3153 }
3156 }
3157 \f
3158 /* Output a library call to function FUN (a SYMBOL_REF rtx).
3159 The RETVAL parameter specifies whether return value needs to be saved, other
3160 parameters are documented in the emit_library_call function below. */
3162 static rtx
3166 {
3167 /* Total size in bytes of all the stack-parms scanned so far. */
3169 /* Size of arguments before any adjustments (such as rounding). */
3172 rtx fun;
3176 CUMULATIVE_ARGS args_so_far;
3177 struct arg
3178 {
3179 rtx value;
3181 rtx reg;
3184 rtx save_area;
3185 };
3190 rtx valreg;
3196 rtx before_call;
3199 #ifdef REG_PARM_STACK_SPACE
3200 /* Define the boundary of the register parm stack space that needs to be
3201 save, if any. */
3204 #endif
3206 /* Size of the stack reserved for parameter registers. */
3212 #ifdef REG_PARM_STACK_SPACE
3214 #endif
3216 /* By default, library functions can not throw. */
3220 {
3244 }
3247 /* Ensure current function's preferred stack boundary is at least
3248 what we need. */
3252 /* If this kind of value comes back in memory,
3253 decide where in memory it should come back. */
3255 {
3258 {
3259 #ifdef PCC_STATIC_STRUCT_RETURN
3260 rtx pointer_reg
3270 else
3272 #endif
3273 /* This call returns a big structure. */
3275 }
3276 }
3277 else
3280 /* ??? Unfinished: must pass the memory address as an argument. */
3282 /* Copy all the libcall-arguments out of the varargs data
3283 and into a vector ARGVEC.
3285 Compute how to pass each argument. We only support a very small subset
3286 of the full argument passing conventions to limit complexity here since
3287 library functions shouldn't have many args. */
3292 #ifdef INIT_CUMULATIVE_LIBCALL_ARGS
3294 #else
3296 #endif
3303 /* Now we are about to start emitting insns that can be deleted
3304 if a libcall is deleted. */
3310 /* If there's a structure value address to be passed,
3311 either pass it in the special place, or pass it as an extra argument. */
3313 {
3316 nargs++;
3318 /* Make sure it is a reasonable operand for a move or push insn. */
3332 #ifdef STACK_PARMS_IN_REG_PARM_AREA
3334 #else
3336 #endif
3345 count++;
3346 }
3349 {
3353 /* We cannot convert the arg value to the mode the library wants here;
3354 must do it earlier where we know the signedness of the arg. */
3358 /* Make sure it is a reasonable operand for a move or push insn. */
3364 {
3365 rtx slot;
3366 int must_copy
3369 /* loop.c won't look at CALL_INSN_FUNCTION_USAGE of const/pure
3370 functions, so we have to pretend this isn't such a function. */
3372 {
3376 }
3379 /* If this was a CONST function, it is now PURE since
3380 it now reads memory. */
3382 {
3385 }
3389 else
3390 {
3394 }
3398 call_fusage);
3402 slot),
3403 call_fusage);
3407 }
3418 #ifdef STACK_PARMS_IN_REG_PARM_AREA
3420 #else
3422 #endif
3433 }
3435 /* If this machine requires an external definition for library
3436 functions, write one out. */
3441 + stack_pointer_delta
3443 / STACK_BYTES
3448 reg_parm_stack_space);
3450 #ifndef OUTGOING_REG_PARM_STACK_SPACE
3452 #endif
3458 {
3459 /* Since the stack pointer will never be pushed, it is possible for
3460 the evaluation of a parm to clobber something we have already
3461 written to the stack. Since most function calls on RISC machines
3462 do not use the stack, this is uncommon, but must work correctly.
3464 Therefore, we save any area of the stack that was already written
3465 and that we are using. Here we set up to do this by making a new
3466 stack usage map from the old one.
3468 Another approach might be to try to reorder the argument
3469 evaluations to avoid this conflicting stack usage. */
3473 #ifndef OUTGOING_REG_PARM_STACK_SPACE
3474 /* Since we will be writing into the entire argument area, the
3475 map must be allocated for its entire size, not just the part that
3476 is the responsibility of the caller. */
3478 #endif
3480 #ifdef ARGS_GROW_DOWNWARD
3483 #else
3485 needed);
3486 #endif
3491 initial_highest_arg_in_use);
3498 /* We must be careful to use virtual regs before they're instantiated,
3499 and real regs afterwards. Loop optimization, for example, can create
3500 new libcalls after we've instantiated the virtual regs, and if we
3501 use virtuals anyway, they won't match the rtl patterns. */
3505 else
3507 }
3508 else
3509 {
3512 }
3514 /* If we push args individually in reverse order, perform stack alignment
3515 before the first push (the last arg). */
3521 {
3524 }
3525 else
3526 {
3529 }
3531 #ifdef REG_PARM_STACK_SPACE
3533 {
3534 /* The argument list is the property of the called routine and it
3535 may clobber it. If the fixed area has been used for previous
3536 parameters, we must save and restore it. */
3539 }
3540 #endif
3542 /* Push the args that need to be pushed. */
3544 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
3545 are to be pushed. */
3547 {
3555 {
3557 {
3558 /* If this is being stored into a pre-allocated, fixed-size,
3559 stack area, save any previous data at that location. */
3561 #ifdef ARGS_GROW_DOWNWARD
3562 /* stack_slot is negative, but we want to index stack_usage_map
3563 with positive values. */
3566 #else
3569 #endif
3572 /* Don't worry about things in the fixed argument area;
3573 it has already been saved. */
3577 i++;
3580 {
3581 /* We need to make a save area. */
3582 unsigned int size
3584 enum machine_mode save_mode
3586 rtx adr
3589 rtx stack_area
3593 {
3600 stack_area,
3602 BLOCK_OP_CALL_PARM);
3603 }
3604 else
3605 {
3609 }
3610 }
3611 }
3616 reg_parm_stack_space,
3619 /* Now mark the segment we just used. */
3624 NO_DEFER_POP;
3625 }
3626 }
3628 /* If we pushed args in forward order, perform stack alignment
3629 after pushing the last arg. */
3636 else
3641 /* Now load any reg parms into their regs. */
3643 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
3644 are to be pushed. */
3646 {
3652 /* Handle calls that pass values in multiple non-contiguous
3653 locations. The PA64 has examples of this for library calls. */
3659 NO_DEFER_POP;
3660 }
3662 /* Any regs containing parms remain in use through the call. */
3664 {
3670 }
3672 /* Pass the function the address in which to return a structure value. */
3674 {
3678 NULL_RTX)));
3681 }
3683 /* Don't allow popping to be deferred, since then
3684 cse'ing of library calls could delete a call and leave the pop. */
3685 NO_DEFER_POP;
3689 /* Stack must be properly aligned now. */
3695 /* We pass the old value of inhibit_defer_pop + 1 to emit_call_1, which
3696 will set inhibit_defer_pop to that value. */
3697 /* The return type is needed to decide how many bytes the function pops.
3698 Signedness plays no role in that, so for simplicity, we pretend it's
3699 always signed. We also assume that the list of arguments passed has
3700 no impact, so we pretend it is unknown. */
3706 struct_value_size,
3708 valreg,
3711 /* For calls to `setjmp', etc., inform flow.c it should complain
3712 if nonvolatile values are live. For functions that cannot return,
3713 inform flow that control does not fall through. */
3716 {
3717 /* The barrier note must be emitted
3718 immediately after the CALL_INSN. Some ports emit more than
3719 just a CALL_INSN above, so we must search for it here. */
3723 {
3725 /* There was no CALL_INSN? */
3727 }
3730 }
3732 /* Now restore inhibit_defer_pop to its actual original value. */
3733 OK_DEFER_POP;
3735 /* If call is cse'able, make appropriate pair of reg-notes around it.
3736 Test valreg so we don't crash; may safely ignore `const'
3737 if return type is void. Disable for PARALLEL return values, because
3738 we have no way to move such values into a pseudo register. */
3740 {
3741 rtx insns;
3744 {
3748 }
3749 else
3750 {
3752 rtx temp;
3756 {
3761 }
3765 /* Construct an "equal form" for the value which mentions all the
3766 arguments in order as well as the function name. */
3779 note);
3784 }
3785 }
3788 /* Copy the value to the right place. */
3790 {
3792 {
3797 }
3799 {
3803 }
3806 else
3808 }
3811 {
3812 #ifdef REG_PARM_STACK_SPACE
3816 #endif
3818 /* If we saved any argument areas, restore them. */
3821 {
3832 BLOCK_OP_CALL_PARM);
3833 else
3835 }
3839 }
3843 }
3844 \f
3845 /* Output a library call to function FUN (a SYMBOL_REF rtx)
3846 (emitting the queue unless NO_QUEUE is nonzero),
3847 for a value of mode OUTMODE,
3848 with NARGS different arguments, passed as alternating rtx values
3849 and machine_modes to convert them to.
3851 FN_TYPE should be LCT_NORMAL for `normal' calls, LCT_CONST for `const'
3852 calls, LCT_PURE for `pure' calls, LCT_CONST_MAKE_BLOCK for `const' calls
3853 which should be enclosed in REG_LIBCALL/REG_RETVAL notes,
3854 LCT_PURE_MAKE_BLOCK for `purep' calls which should be enclosed in
3855 REG_LIBCALL/REG_RETVAL notes with extra (use (memory (scratch)),
3856 or other LCT_ value for other types of library calls. */
3858 void
3861 {
3867 }
3868 \f
3869 /* Like emit_library_call except that an extra argument, VALUE,
3870 comes second and says where to store the result.
3871 (If VALUE is zero, this function chooses a convenient way
3872 to return the value.
3874 This function returns an rtx for where the value is to be found.
3875 If VALUE is nonzero, VALUE is returned. */
3877 rtx
3881 {
3882 rtx result;
3891 }
3892 \f
3893 /* Store a single argument for a function call
3894 into the register or memory area where it must be passed.
3895 *ARG describes the argument value and where to pass it.
3897 ARGBLOCK is the address of the stack-block for all the arguments,
3898 or 0 on a machine where arguments are pushed individually.
3900 MAY_BE_ALLOCA nonzero says this could be a call to `alloca'
3901 so must be careful about how the stack is used.
3903 VARIABLE_SIZE nonzero says that this was a variable-sized outgoing
3904 argument stack. This is used if ACCUMULATE_OUTGOING_ARGS to indicate
3905 that we need not worry about saving and restoring the stack.
3907 FNDECL is the declaration of the function we are calling.
3909 Return nonzero if this arg should cause sibcall failure,
3910 zero otherwise. */
3912 static int
3915 {
3926 /* Push a new temporary level for any temporaries we make for
3927 this argument. */
3931 {
3932 /* If this is being stored into a pre-allocated, fixed-size, stack area,
3933 save any previous data at that location. */
3935 {
3936 #ifdef ARGS_GROW_DOWNWARD
3937 /* stack_slot is negative, but we want to index stack_usage_map
3938 with positive values. */
3941 else
3945 #else
3948 else
3952 #endif
3955 /* Don't worry about things in the fixed argument area;
3956 it has already been saved. */
3960 i++;
3963 {
3964 /* We need to make a save area. */
3971 {
3980 BLOCK_OP_CALL_PARM);
3981 }
3982 else
3983 {
3986 }
3987 }
3988 }
3989 }
3991 /* If this isn't going to be placed on both the stack and in registers,
3992 set up the register and number of words. */
3994 {
3997 else
4000 }
4002 /* Being passed entirely in a register. We shouldn't be called in
4003 this case. */
4006 /* If this arg needs special alignment, don't load the registers
4007 here. */
4011 /* If this is being passed partially in a register, we can't evaluate
4012 it directly into its stack slot. Otherwise, we can. */
4014 {
4015 /* stack_arg_under_construction is nonzero if a function argument is
4016 being evaluated directly into the outgoing argument list and
4017 expand_call must take special action to preserve the argument list
4018 if it is called recursively.
4020 For scalar function arguments stack_usage_map is sufficient to
4021 determine which stack slots must be saved and restored. Scalar
4022 arguments in general have pass_on_stack == 0.
4024 If this argument is initialized by a function which takes the
4025 address of the argument (a C++ constructor or a C function
4026 returning a BLKmode structure), then stack_usage_map is
4027 insufficient and expand_call must push the stack around the
4028 function call. Such arguments have pass_on_stack == 1.
4030 Note that it is always safe to set stack_arg_under_construction,
4031 but this generates suboptimal code if set when not needed. */
4034 stack_arg_under_construction++;
4037 (partial
4042 /* If we are promoting object (or for any other reason) the mode
4043 doesn't agree, convert the mode. */
4050 stack_arg_under_construction--;
4051 }
4053 /* Don't allow anything left on stack from computation
4054 of argument to alloca. */
4059 /* If the value is already in the stack slot, we are done. */
4060 ;
4062 {
4065 /* Argument is a scalar, not entirely passed in registers.
4066 (If part is passed in registers, arg->partial says how much
4067 and emit_push_insn will take care of putting it there.)
4069 Push it, and if its size is less than the
4070 amount of space allocated to it,
4071 also bump stack pointer by the additional space.
4072 Note that in C the default argument promotions
4073 will prevent such mismatches. */
4076 /* Compute how much space the push instruction will push.
4077 On many machines, pushing a byte will advance the stack
4078 pointer by a halfword. */
4079 #ifdef PUSH_ROUNDING
4081 #endif
4084 /* Compute how much space the argument should get:
4085 round up to a multiple of the alignment for arguments. */
4091 /* This isn't already where we want it on the stack, so put it there.
4092 This can either be done with push or copy insns. */
4098 /* Unless this is a partially-in-register argument, the argument is now
4099 in the stack. */
4102 }
4103 else
4104 {
4105 /* BLKmode, at least partly to be pushed. */
4109 rtx size_rtx;
4111 /* Pushing a nonscalar.
4112 If part is passed in registers, PARTIAL says how much
4113 and emit_push_insn will take care of putting it there. */
4115 /* Round its size up to a multiple
4116 of the allocation unit for arguments. */
4119 {
4122 }
4123 else
4124 {
4125 /* PUSH_ROUNDING has no effect on us, because emit_push_insn
4126 for BLKmode is careful to avoid it. */
4132 }
4136 /* When an argument is padded down, the block is aligned to
4137 PARM_BOUNDARY, but the actual argument isn't. */
4139 {
4143 {
4146 }
4147 }
4150 {
4151 /* emit_push_insn might not work properly if arg->value and
4152 argblock + arg->locate.offset areas overlap. */
4159 current_function_internal_arg_pointer
4161 {
4165 /* expand_call should ensure this. */
4170 {
4173 }
4175 {
4178 }
4179 }
4180 }
4187 /* Unless this is a partially-in-register argument, the argument is now
4188 in the stack.
4190 ??? Unlike the case above, in which we want the actual
4191 address of the data, so that we can load it directly into a
4192 register, here we want the address of the stack slot, so that
4193 it's properly aligned for word-by-word copying or something
4194 like that. It's not clear that this is always correct. */
4197 }
4200 {
4202 arg->parallel_value
4205 }
4207 /* Mark all slots this store used. */
4213 /* Once we have pushed something, pops can't safely
4214 be deferred during the rest of the arguments. */
4215 NO_DEFER_POP;
4217 /* Free any temporary slots made in processing this argument. Show
4218 that we might have taken the address of something and pushed that
4219 as an operand. */
4225 }
4227 /* Nonzero if we do not know how to pass TYPE solely in registers. */
4229 bool
4231 tree type)
4232 {
4236 /* If the type has variable size... */
4240 /* If the type is marked as addressable (it is required
4241 to be constructed into the stack)... */
4246 }
4248 /* Another version of the TARGET_MUST_PASS_IN_STACK hook. This one
4249 takes trailing padding of a structure into account. */
4250 /* ??? Should be able to merge these two by examining BLOCK_REG_PADDING. */
4252 bool
4254 {
4258 /* If the type has variable size... */
4262 /* If the type is marked as addressable (it is required
4263 to be constructed into the stack)... */
4267 /* If the padding and mode of the type is such that a copy into
4268 a register would put it into the wrong part of the register. */
4276 }