| blob | 8723e1f4fae8ccecbbc0a6bb53cfad81d4913329 |
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, 2006, 2007
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 {
562 }
564 /* Detect flags (function attributes) from the function decl or type node. */
566 int
568 {
573 {
576 /* The function exp may have the `malloc' attribute. */
580 /* The function exp may have the `returns_twice' attribute. */
584 /* The function exp may have the `pure' attribute. */
598 }
605 /* Mark if the function returns with the stack pointer depressed. We
606 cannot consider it pure or constant in that case. */
608 {
611 }
614 }
616 /* Detect flags from a CALL_EXPR. */
618 int
620 {
626 else
627 {
631 else
633 }
636 }
638 /* Precompute all register parameters as described by ARGS, storing values
639 into fields within the ARGS array.
641 NUM_ACTUALS indicates the total number elements in the ARGS array.
643 Set REG_PARM_SEEN if we encounter a register parameter. */
645 static void
648 {
655 {
659 {
664 }
666 /* If the value is a non-legitimate constant, force it into a
667 pseudo now. TLS symbols sometimes need a call to resolve. */
672 /* If we are to promote the function arg to a wider mode,
673 do it now. */
681 /* If we're going to have to load the value by parts, pull the
682 parts into pseudos. The part extraction process can involve
683 non-trivial computation. */
685 {
690 }
692 /* If the value is expensive, and we are inside an appropriately
693 short loop, put the value into a pseudo and then put the pseudo
694 into the hard reg.
696 For small register classes, also do this if this call uses
697 register parameters. This is to avoid reload conflicts while
698 loading the parameters registers. */
708 }
709 }
711 #ifdef REG_PARM_STACK_SPACE
713 /* The argument list is the property of the called routine and it
714 may clobber it. If the fixed area has been used for previous
715 parameters, we must save and restore it. */
717 static rtx
718 save_fixed_argument_area (int reg_parm_stack_space, rtx argblock, int *low_to_save, int *high_to_save)
719 {
723 /* Compute the boundary of the area that needs to be saved, if any. */
725 #ifdef ARGS_GROW_DOWNWARD
727 #endif
733 {
737 rtx stack_area;
738 rtx save_area;
741 ;
749 /* If we don't have the required alignment, must do this
750 in BLKmode. */
755 #ifdef ARGS_GROW_DOWNWARD
757 #else
759 #endif
763 delta)));
767 {
771 }
772 else
773 {
776 }
779 }
782 }
784 static void
786 {
789 rtx stack_area;
791 #ifdef ARGS_GROW_DOWNWARD
793 #else
795 #endif
803 else
806 BLOCK_OP_CALL_PARM);
807 }
810 /* If any elements in ARGS refer to parameters that are to be passed in
811 registers, but not in memory, and whose alignment does not permit a
812 direct copy into registers. Copy the values into a group of pseudos
813 which we will later copy into the appropriate hard registers.
815 Pseudos for each unaligned argument will be stored into the array
816 args[argnum].aligned_regs. The caller is responsible for deallocating
817 the aligned_regs array if it is nonzero. */
819 static void
821 {
829 {
834 {
837 }
838 else
839 {
842 }
846 /* Structures smaller than a word are normally aligned to the
847 least significant byte. On a BYTES_BIG_ENDIAN machine,
848 this means we must skip the empty high order bytes when
849 calculating the bit offset. */
851 #ifdef BLOCK_REG_PADDING
855 #else
856 && BYTES_BIG_ENDIAN
857 #endif
858 )
862 {
871 /* There is no need to restrict this code to loading items
872 in TYPE_ALIGN sized hunks. The bitfield instructions can
873 load up entire word sized registers efficiently.
875 ??? This may not be needed anymore.
876 We use to emit a clobber here but that doesn't let later
877 passes optimize the instructions we emit. By storing 0 into
878 the register later passes know the first AND to zero out the
879 bitfield being set in the register is unnecessary. The store
880 of 0 will be deleted as will at least the first AND. */
886 word);
887 }
888 }
889 }
891 /* Fill in ARGS_SIZE and ARGS array based on the parameters found in
892 CALL_EXPR EXP.
894 NUM_ACTUALS is the total number of parameters.
896 N_NAMED_ARGS is the total number of named arguments.
898 STRUCT_VALUE_ADDR_VALUE is the implicit argument for a struct return
899 value, or null.
901 FNDECL is the tree code for the target of this call (if known)
903 ARGS_SO_FAR holds state needed by the target to know where to place
904 the next argument.
906 REG_PARM_STACK_SPACE is the number of bytes of stack space reserved
907 for arguments which are passed in registers.
909 OLD_STACK_LEVEL is a pointer to an rtx which olds the old stack level
910 and may be modified by this routine.
912 OLD_PENDING_ADJ, MUST_PREALLOCATE and FLAGS are pointers to integer
913 flags which may may be modified by this routine.
915 MAY_TAILCALL is cleared if we encounter an invisible pass-by-reference
916 that requires allocation of stack space.
918 CALL_FROM_THUNK_P is true if this call is the jump from a thunk to
919 the thunked-to function. */
921 static void
927 tree fndecl,
933 {
934 /* 1 if scanning parms front to back, -1 if scanning back to front. */
937 /* Count arg position in order args appear. */
945 /* In this loop, we consider args in the order they are written.
946 We fill up ARGS from the front or from the back if necessary
947 so that in any case the first arg to be pushed ends up at the front. */
950 {
952 /* In this case, must reverse order of args
953 so that we compute and push the last arg first. */
954 }
955 else
956 {
958 }
960 /* First fill in the actual arguments in the ARGS array, splitting
961 complex arguments if necessary. */
962 {
964 call_expr_arg_iterator iter;
965 tree arg;
968 {
971 }
973 {
976 && argtype
979 {
985 }
986 else
989 }
990 }
992 /* I counts args in order (to be) pushed; ARGPOS counts in order written. */
994 {
999 /* Replace erroneous argument with constant zero. */
1003 /* If TYPE is a transparent union, pass things the way we would
1004 pass the first field of the union. We have already verified that
1005 the modes are the same. */
1009 /* Decide where to pass this arg.
1011 args[i].reg is nonzero if all or part is passed in registers.
1013 args[i].partial is nonzero if part but not all is passed in registers,
1014 and the exact value says how many bytes are passed in registers.
1016 args[i].pass_on_stack is nonzero if the argument must at least be
1017 computed on the stack. It may then be loaded back into registers
1018 if args[i].reg is nonzero.
1020 These decisions are driven by the FUNCTION_... macros and must agree
1021 with those made by function.c. */
1023 /* See if this argument should be passed by invisible reference. */
1026 {
1028 tree base;
1030 callee_copies
1034 /* If we're compiling a thunk, pass through invisible references
1035 instead of making a copy. */
1037 || (callee_copies
1041 {
1042 /* We can't use sibcalls if a callee-copied argument is
1043 stored in the current function's frame. */
1051 }
1052 else
1053 {
1054 /* We make a copy of the object and pass the address to the
1055 function being called. */
1056 rtx copy;
1062 STACK_CHECK_MAX_VAR_SIZE))))
1063 {
1064 /* This is a variable-sized object. Make space on the stack
1065 for it. */
1069 {
1073 }
1076 allocate_dynamic_stack_space
1079 }
1080 else
1087 else
1094 }
1095 }
1108 #ifdef FUNCTION_INCOMING_ARG
1109 /* If this is a sibling call and the machine has register windows, the
1110 register window has to be unwinded before calling the routine, so
1111 arguments have to go into the incoming registers. */
1114 #else
1116 #endif
1125 /* If FUNCTION_ARG returned a (parallel [(expr_list (nil) ...) ...]),
1126 it means that we are to pass this arg in the register(s) designated
1127 by the PARALLEL, but also to pass it in the stack. */
1132 /* If this is an addressable type, we must preallocate the stack
1133 since we must evaluate the object into its final location.
1135 If this is to be passed in both registers and the stack, it is simpler
1136 to preallocate. */
1141 /* If this is an addressable type, we cannot pre-evaluate it. Thus,
1142 we cannot consider this function call constant. */
1146 /* Compute the stack-size of this argument. */
1151 #ifdef STACK_PARMS_IN_REG_PARM_AREA
1153 #else
1155 #endif
1158 #ifdef BLOCK_REG_PADDING
1159 else
1160 /* The argument is passed entirely in registers. See at which
1161 end it should be padded. */
1165 #endif
1167 /* Update ARGS_SIZE, the total stack space for args so far. */
1173 /* Increment ARGS_SO_FAR, which has info about which arg-registers
1174 have been used, etc. */
1178 }
1179 }
1181 /* Update ARGS_SIZE to contain the total size for the argument block.
1182 Return the original constant component of the argument block's size.
1184 REG_PARM_STACK_SPACE holds the number of bytes of stack space reserved
1185 for arguments passed in registers. */
1187 static int
1191 {
1194 /* For accumulate outgoing args mode we don't need to align, since the frame
1195 will be already aligned. Align to STACK_BOUNDARY in order to prevent
1196 backends from generating misaligned frame sizes. */
1200 /* Compute the actual size of the argument block required. The variable
1201 and constant sizes must be combined, the size may have to be rounded,
1202 and there may be a minimum required size. */
1205 {
1211 {
1212 /* We don't handle this case yet. To handle it correctly we have
1213 to add the delta, round and subtract the delta.
1214 Currently no machine description requires this support. */
1217 }
1220 {
1221 args_size->var
1225 #ifndef OUTGOING_REG_PARM_STACK_SPACE
1226 /* The area corresponding to register parameters is not to count in
1227 the size of the block we need. So make the adjustment. */
1228 args_size->var
1231 #endif
1232 }
1233 }
1234 else
1235 {
1240 + stack_pointer_delta
1242 / preferred_stack_boundary
1247 reg_parm_stack_space);
1249 #ifndef OUTGOING_REG_PARM_STACK_SPACE
1251 #endif
1252 }
1254 }
1256 /* Precompute parameters as needed for a function call.
1258 FLAGS is mask of ECF_* constants.
1260 NUM_ACTUALS is the number of arguments.
1262 ARGS is an array containing information for each argument; this
1263 routine fills in the INITIAL_VALUE and VALUE fields for each
1264 precomputed argument. */
1266 static void
1268 {
1271 /* If this is a libcall, then precompute all arguments so that we do not
1272 get extraneous instructions emitted as part of the libcall sequence. */
1277 {
1280 /* If this is an addressable type, we cannot pre-evaluate it. */
1288 {
1292 #if defined(PROMOTE_FUNCTION_MODE) && !defined(PROMOTE_MODE)
1293 /* CSE will replace this only if it contains args[i].value
1294 pseudo, so convert it down to the declared mode using
1295 a SUBREG. */
1298 {
1304 }
1305 #endif
1306 }
1307 }
1308 }
1310 /* Given the current state of MUST_PREALLOCATE and information about
1311 arguments to a function call in NUM_ACTUALS, ARGS and ARGS_SIZE,
1312 compute and return the final value for MUST_PREALLOCATE. */
1314 static int
1317 {
1318 /* See if we have or want to preallocate stack space.
1320 If we would have to push a partially-in-regs parm
1321 before other stack parms, preallocate stack space instead.
1323 If the size of some parm is not a multiple of the required stack
1324 alignment, we must preallocate.
1326 If the total size of arguments that would otherwise create a copy in
1327 a temporary (such as a CALL) is more than half the total argument list
1328 size, preallocation is faster.
1330 Another reason to preallocate is if we have a machine (like the m88k)
1331 where stack alignment is required to be maintained between every
1332 pair of insns, not just when the call is made. However, we assume here
1333 that such machines either do not have push insns (and hence preallocation
1334 would occur anyway) or the problem is taken care of with
1335 PUSH_ROUNDING. */
1338 {
1344 {
1355 copy_to_evaluate_size
1357 }
1362 }
1364 }
1366 /* If we preallocated stack space, compute the address of each argument
1367 and store it into the ARGS array.
1369 We need not ensure it is a valid memory address here; it will be
1370 validized when it is used.
1372 ARGBLOCK is an rtx for the address of the outgoing arguments. */
1374 static void
1376 {
1378 {
1386 {
1389 rtx addr;
1394 /* Skip this parm if it will not be passed on the stack. */
1402 else
1408 {
1409 /* Only part of the parameter is being passed on the stack.
1410 Generate a simple memory reference of the correct size. */
1416 }
1417 else
1418 {
1422 }
1428 {
1431 }
1436 else
1442 {
1443 /* Only part of the parameter is being passed on the stack.
1444 Generate a simple memory reference of the correct size.
1445 */
1448 }
1449 else
1450 {
1454 }
1457 /* Function incoming arguments may overlap with sibling call
1458 outgoing arguments and we cannot allow reordering of reads
1459 from function arguments with stores to outgoing arguments
1460 of sibling calls. */
1463 }
1464 }
1465 }
1467 /* Given a FNDECL and EXP, return an rtx suitable for use as a target address
1468 in a call instruction.
1470 FNDECL is the tree node for the target function. For an indirect call
1471 FNDECL will be NULL_TREE.
1473 ADDR is the operand 0 of CALL_EXPR for this call. */
1475 static rtx
1477 {
1478 rtx funexp;
1480 /* Get the function to call, in the form of RTL. */
1482 {
1483 /* If this is the first use of the function, see if we need to
1484 make an external definition for it. */
1486 {
1489 }
1491 /* Get a SYMBOL_REF rtx for the function address. */
1493 }
1494 else
1495 /* Generate an rtx (probably a pseudo-register) for the address. */
1496 {
1500 }
1502 }
1504 /* Return true if and only if SIZE storage units (usually bytes)
1505 starting from address ADDR overlap with already clobbered argument
1506 area. This function is used to determine if we should give up a
1507 sibcall. */
1509 static bool
1511 {
1512 HOST_WIDE_INT i;
1520 /* Return true for arg pointer based indexed addressing. */
1525 else
1528 #ifdef ARGS_GROW_DOWNWARD
1530 #endif
1532 {
1539 }
1542 }
1544 /* Do the register loads required for any wholly-register parms or any
1545 parms which are passed both on the stack and in a register. Their
1546 expressions were already evaluated.
1548 Mark all register-parms as living through the call, putting these USE
1549 insns in the CALL_INSN_FUNCTION_USAGE field.
1551 When IS_SIBCALL, perform the check_sibcall_argument_overlap
1552 checking, setting *SIBCALL_FAILURE if appropriate. */
1554 static void
1558 {
1562 {
1566 {
1571 /* Set non-negative if we must move a word at a time, even if
1572 just one word (e.g, partial == 4 && mode == DFmode). Set
1573 to -1 if we just use a normal move insn. This value can be
1574 zero if the argument is a zero size structure. */
1577 ;
1579 {
1582 }
1584 {
1587 }
1588 else
1591 /* Handle calls that pass values in multiple non-contiguous
1592 locations. The Irix 6 ABI has examples of this. */
1597 /* If simple case, just do move. If normal partial, store_one_arg
1598 has already loaded the register for us. In all other cases,
1599 load the register(s) from memory. */
1602 {
1604 #ifdef BLOCK_REG_PADDING
1605 /* Handle case where we have a value that needs shifting
1606 up to the msb. eg. a QImode value and we're padding
1607 upward on a BYTES_BIG_ENDIAN machine. */
1611 {
1612 rtx x;
1615 /* Assigning REG here rather than a temp makes CALL_FUSAGE
1616 report the whole reg as used. Strictly speaking, the
1617 call only uses SIZE bytes at the msb end, but it doesn't
1618 seem worth generating rtl to say that. */
1625 }
1626 #endif
1627 }
1629 /* If we have pre-computed the values to put in the registers in
1630 the case of non-aligned structures, copy them in now. */
1638 {
1641 /* Check for overlap with already clobbered argument area. */
1644 size))
1647 /* Handle a BLKmode that needs shifting. */
1649 #ifdef BLOCK_REG_PADDING
1651 #else
1652 && BYTES_BIG_ENDIAN
1653 #endif
1654 )
1655 {
1669 }
1670 else
1672 }
1674 /* When a parameter is a block, and perhaps in other cases, it is
1675 possible that it did a load from an argument slot that was
1676 already clobbered. */
1681 /* Handle calls that pass values in multiple non-contiguous
1682 locations. The Irix 6 ABI has examples of this. */
1689 }
1690 }
1691 }
1693 /* We need to pop PENDING_STACK_ADJUST bytes. But, if the arguments
1694 wouldn't fill up an even multiple of PREFERRED_UNIT_STACK_BOUNDARY
1695 bytes, then we would need to push some additional bytes to pad the
1696 arguments. So, we compute an adjust to the stack pointer for an
1697 amount that will leave the stack under-aligned by UNADJUSTED_ARGS_SIZE
1698 bytes. Then, when the arguments are pushed the stack will be perfectly
1699 aligned. ARGS_SIZE->CONSTANT is set to the number of bytes that should
1700 be popped after the call. Returns the adjustment. */
1702 static int
1706 {
1707 /* The number of bytes to pop so that the stack will be
1708 under-aligned by UNADJUSTED_ARGS_SIZE bytes. */
1709 HOST_WIDE_INT adjustment;
1710 /* The alignment of the stack after the arguments are pushed, if we
1711 just pushed the arguments without adjust the stack here. */
1714 unadjusted_alignment
1718 /* We want to get rid of as many of the PENDING_STACK_ADJUST bytes
1719 as possible -- leaving just enough left to cancel out the
1720 UNADJUSTED_ALIGNMENT. In other words, we want to ensure that the
1721 PENDING_STACK_ADJUST is non-negative, and congruent to
1722 -UNADJUSTED_ALIGNMENT modulo the PREFERRED_UNIT_STACK_BOUNDARY. */
1724 /* Begin by trying to pop all the bytes. */
1725 unadjusted_alignment
1726 = (unadjusted_alignment
1729 /* Push enough additional bytes that the stack will be aligned
1730 after the arguments are pushed. */
1732 {
1735 else
1737 }
1739 /* Now, sets ARGS_SIZE->CONSTANT so that we pop the right number of
1740 bytes after the call. The right number is the entire
1741 PENDING_STACK_ADJUST less our ADJUSTMENT plus the amount required
1742 by the arguments in the first place. */
1743 args_size->constant
1747 }
1749 /* Scan X expression if it does not dereference any argument slots
1750 we already clobbered by tail call arguments (as noted in stored_args_map
1751 bitmap).
1752 Return nonzero if X expression dereferences such argument slots,
1753 zero otherwise. */
1755 static int
1757 {
1758 RTX_CODE code;
1771 /* Scan all subexpressions. */
1774 {
1776 {
1779 }
1781 {
1785 }
1786 }
1788 }
1790 /* Scan sequence after INSN if it does not dereference any argument slots
1791 we already clobbered by tail call arguments (as noted in stored_args_map
1792 bitmap). If MARK_STORED_ARGS_MAP, add stack slots for ARG to
1793 stored_args_map bitmap afterwards (when ARG is a register MARK_STORED_ARGS_MAP
1794 should be 0). Return nonzero if sequence after INSN dereferences such argument
1795 slots, zero otherwise. */
1797 static int
1799 {
1804 else
1813 {
1814 #ifdef ARGS_GROW_DOWNWARD
1816 #else
1818 #endif
1822 }
1824 }
1826 /* Given that a function returns a value of mode MODE at the most
1827 significant end of hard register VALUE, shift VALUE left or right
1828 as specified by LEFT_P. Return true if some action was needed. */
1830 bool
1832 {
1833 HOST_WIDE_INT shift;
1840 /* Use ashr rather than lshr for right shifts. This is for the benefit
1841 of the MIPS port, which requires SImode values to be sign-extended
1842 when stored in 64-bit registers. */
1847 }
1849 /* Generate all the code for a CALL_EXPR exp
1850 and return an rtx for its value.
1851 Store the value in TARGET (specified as an rtx) if convenient.
1852 If the value is stored in TARGET then TARGET is returned.
1853 If IGNORE is nonzero, then we ignore the value of the function call. */
1855 rtx
1857 {
1858 /* Nonzero if we are currently expanding a call. */
1861 /* RTX for the function to be called. */
1862 rtx funexp;
1863 /* Sequence of insns to perform a normal "call". */
1865 /* Sequence of insns to perform a tail "call". */
1867 /* Data type of the function. */
1868 tree funtype;
1869 tree type_arg_types;
1870 /* Declaration of the function being called,
1871 or 0 if the function is computed (not known by name). */
1873 /* The type of the function being called. */
1874 tree fntype;
1878 /* Register in which non-BLKmode value will be returned,
1879 or 0 if no value or if value is BLKmode. */
1880 rtx valreg;
1881 /* Address where we should return a BLKmode value;
1882 0 if value not BLKmode. */
1884 /* Nonzero if that address is being passed by treating it as
1885 an extra, implicit first parameter. Otherwise,
1886 it is passed by being copied directly into struct_value_rtx. */
1888 /* Holds the value of implicit argument for the struct value. */
1890 /* Size of aggregate value wanted, or zero if none wanted
1891 or if we are using the non-reentrant PCC calling convention
1892 or expecting the value in registers. */
1894 /* Nonzero if called function returns an aggregate in memory PCC style,
1895 by returning the address of where to find it. */
1899 /* Number of actual parameters in this call, including struct value addr. */
1901 /* Number of named args. Args after this are anonymous ones
1902 and they must all go on the stack. */
1904 /* Number of complex actual arguments that need to be split. */
1907 /* Vector of information about each argument.
1908 Arguments are numbered in the order they will be pushed,
1909 not the order they are written. */
1912 /* Total size in bytes of all the stack-parms scanned so far. */
1915 /* Size of arguments before any adjustments (such as rounding). */
1917 /* Data on reg parms scanned so far. */
1918 CUMULATIVE_ARGS args_so_far;
1919 /* Nonzero if a reg parm has been scanned. */
1921 /* Nonzero if this is an indirect function call. */
1923 /* Nonzero if we must avoid push-insns in the args for this call.
1924 If stack space is allocated for register parameters, but not by the
1925 caller, then it is preallocated in the fixed part of the stack frame.
1926 So the entire argument block must then be preallocated (i.e., we
1927 ignore PUSH_ROUNDING in that case). */
1931 /* Size of the stack reserved for parameter registers. */
1934 /* Address of space preallocated for stack parms
1935 (on machines that lack push insns), or 0 if space not preallocated. */
1938 /* Mask of ECF_ flags. */
1940 #ifdef REG_PARM_STACK_SPACE
1941 /* Define the boundary of the register parm stack space that needs to be
1942 saved, if any. */
1945 #endif
1953 /* State variables to track stack modifications. */
1959 /* Some stack pointer alterations we make are performed via
1960 allocate_dynamic_stack_space. This modifies the stack_pointer_delta,
1961 which we then also need to save/restore along the way. */
1964 rtx call_fusage;
1968 /* The alignment of the stack, in bits. */
1970 /* The alignment of the stack, in bytes. */
1972 /* The static chain value to use for this call. */
1973 rtx static_chain_value;
1974 /* See if this is "nothrow" function call. */
1978 /* See if we can find a DECL-node for the actual function, and get the
1979 function attributes (flags) from the function decl or type node. */
1982 {
1985 }
1986 else
1987 {
1990 }
1994 /* Warn if this value is an aggregate type,
1995 regardless of which calling convention we are using for it. */
1999 /* If the result of a pure or const function call is ignored (or void),
2000 and none of its arguments are volatile, we can avoid expanding the
2001 call and just evaluate the arguments for side-effects. */
2005 {
2007 tree arg;
2008 call_expr_arg_iterator iter;
2012 {
2015 }
2018 {
2022 }
2023 }
2025 #ifdef REG_PARM_STACK_SPACE
2027 #endif
2029 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2032 #endif
2034 /* Set up a place to return a structure. */
2036 /* Cater to broken compilers. */
2038 {
2039 /* This call returns a big structure. */
2042 #ifdef PCC_STATIC_STRUCT_RETURN
2043 {
2045 }
2047 {
2052 else
2053 {
2054 /* For variable-sized objects, we must be called with a target
2055 specified. If we were to allocate space on the stack here,
2056 we would have no way of knowing when to free it. */
2062 }
2063 }
2065 }
2067 /* Figure out the amount to which the stack should be aligned. */
2070 {
2074 }
2076 /* Operand 0 is a pointer-to-function; get the type of the function. */
2081 /* Count whether there are actual complex arguments that need to be split
2082 into their real and imaginary parts. Munge the type_arg_types
2083 appropriately here as well. */
2085 {
2086 call_expr_arg_iterator iter;
2087 tree arg;
2089 {
2093 num_complex_actuals++;
2094 }
2096 }
2097 else
2103 /* If struct_value_rtx is 0, it means pass the address
2104 as if it were an extra parameter. Put the argument expression
2105 in structure_value_addr_value. */
2107 {
2108 /* If structure_value_addr is a REG other than
2109 virtual_outgoing_args_rtx, we can use always use it. If it
2110 is not a REG, we must always copy it into a register.
2111 If it is virtual_outgoing_args_rtx, we must copy it to another
2112 register in some cases. */
2114 || (ACCUMULATE_OUTGOING_ARGS
2115 && stack_arg_under_construction
2121 structure_value_addr_value =
2124 }
2126 /* Count the arguments and set NUM_ACTUALS. */
2127 num_actuals =
2130 /* Compute number of named args.
2131 First, do a raw count of the args for INIT_CUMULATIVE_ARGS. */
2134 n_named_args
2136 /* Count the struct value address, if it is passed as a parm. */
2138 else
2139 /* If we know nothing, treat all args as named. */
2142 /* Start updating where the next arg would go.
2144 On some machines (such as the PA) indirect calls have a different
2145 calling convention than normal calls. The fourth argument in
2146 INIT_CUMULATIVE_ARGS tells the backend if this is an indirect call
2147 or not. */
2150 /* Now possibly adjust the number of named args.
2151 Normally, don't include the last named arg if anonymous args follow.
2152 We do include the last named arg if
2153 targetm.calls.strict_argument_naming() returns nonzero.
2154 (If no anonymous args follow, the result of list_length is actually
2155 one too large. This is harmless.)
2157 If targetm.calls.pretend_outgoing_varargs_named() returns
2158 nonzero, and targetm.calls.strict_argument_naming() returns zero,
2159 this machine will be able to place unnamed args that were passed
2160 in registers into the stack. So treat all args as named. This
2161 allows the insns emitting for a specific argument list to be
2162 independent of the function declaration.
2164 If targetm.calls.pretend_outgoing_varargs_named() returns zero,
2165 we do not have any reliable way to pass unnamed args in
2166 registers, so we must force them into memory. */
2170 ;
2173 /* Don't include the last named arg. */
2175 else
2176 /* Treat all args as named. */
2179 /* Make a vector to hold all the information about each arg. */
2183 /* Build up entries in the ARGS array, compute the size of the
2184 arguments into ARGS_SIZE, etc. */
2194 {
2195 /* If this function requires a variable-sized argument list, don't
2196 try to make a cse'able block for this call. We may be able to
2197 do this eventually, but it is too complicated to keep track of
2198 what insns go in the cse'able block and which don't. */
2202 }
2204 /* Now make final decision about preallocating stack space. */
2209 /* If the structure value address will reference the stack pointer, we
2210 must stabilize it. We don't need to do this if we know that we are
2211 not going to adjust the stack pointer in processing this call. */
2216 structure_value_addr))
2221 /* Tail calls can make things harder to debug, and we've traditionally
2222 pushed these optimizations into -O2. Don't try if we're already
2223 expanding a call, as that means we're an argument. Don't try if
2224 there's cleanups, as we know there's code to follow the call. */
2227 || !flag_optimize_sibling_calls
2232 /* Rest of purposes for tail call optimizations to fail. */
2234 #ifdef HAVE_sibcall_epilogue
2235 !HAVE_sibcall_epilogue
2236 #else
2237 1
2238 #endif
2239 || !try_tail_call
2240 /* Doing sibling call optimization needs some work, since
2241 structure_value_addr can be allocated on the stack.
2242 It does not seem worth the effort since few optimizable
2243 sibling calls will return a structure. */
2245 /* Check whether the target is able to optimize the call
2246 into a sibcall. */
2248 /* Functions that do not return exactly once may not be sibcall
2249 optimized. */
2252 /* If the called function is nested in the current one, it might access
2253 some of the caller's arguments, but could clobber them beforehand if
2254 the argument areas are shared. */
2256 /* If this function requires more stack slots than the current
2257 function, we cannot change it into a sibling call.
2258 current_function_pretend_args_size is not part of the
2259 stack allocated by our caller. */
2262 /* If the callee pops its own arguments, then it must pop exactly
2263 the same number of arguments as the current function. */
2267 current_function_args_size))
2271 /* Ensure current function's preferred stack boundary is at least
2272 what we need. We don't have to increase alignment for recursive
2273 functions. */
2282 /* We want to make two insn chains; one for a sibling call, the other
2283 for a normal call. We will select one of the two chains after
2284 initial RTL generation is complete. */
2286 {
2288 /* We want to emit any pending stack adjustments before the tail
2289 recursion "call". That way we know any adjustment after the tail
2290 recursion call can be ignored if we indeed use the tail
2291 call expansion. */
2294 rtx insns;
2298 {
2299 /* State variables we need to save and restore between
2300 iterations. */
2303 }
2306 else
2309 /* Other state variables that we must reinitialize each time
2310 through the loop (that are not initialized by the loop itself). */
2314 /* Start a new sequence for the normal call case.
2316 From this point on, if the sibling call fails, we want to set
2317 sibcall_failure instead of continuing the loop. */
2320 /* Don't let pending stack adjusts add up to too much.
2321 Also, do all pending adjustments now if there is any chance
2322 this might be a call to alloca or if we are expanding a sibling
2323 call sequence or if we are calling a function that is to return
2324 with stack pointer depressed.
2325 Also do the adjustments before a throwing call, otherwise
2326 exception handling can fail; PR 19225. */
2335 /* When calling a const function, we must pop the stack args right away,
2336 so that the pop is deleted or moved with the call. */
2338 NO_DEFER_POP;
2340 /* Precompute any arguments as needed. */
2344 /* Now we are about to start emitting insns that can be deleted
2345 if a libcall is deleted. */
2353 /* Compute the actual size of the argument block required. The variable
2354 and constant sizes must be combined, the size may have to be rounded,
2355 and there may be a minimum required size. When generating a sibcall
2356 pattern, do not round up, since we'll be re-using whatever space our
2357 caller provided. */
2358 unadjusted_args_size
2366 /* The argument block when performing a sibling call is the
2367 incoming argument block. */
2369 {
2371 argblock
2372 #ifdef STACK_GROWS_DOWNWARD
2374 #else
2376 #endif
2379 }
2381 /* If we have no actual push instructions, or shouldn't use them,
2382 make space for all args right now. */
2384 {
2386 {
2391 /* stack_arg_under_construction says whether a stack arg is
2392 being constructed at the old stack level. Pushing the stack
2393 gets a clean outgoing argument block. */
2396 }
2398 }
2399 else
2400 {
2401 /* Note that we must go through the motions of allocating an argument
2402 block even if the size is zero because we may be storing args
2403 in the area reserved for register arguments, which may be part of
2404 the stack frame. */
2408 /* Store the maximum argument space used. It will be pushed by
2409 the prologue (if ACCUMULATE_OUTGOING_ARGS, or stack overflow
2410 checking). */
2416 {
2418 {
2419 /* Since the stack pointer will never be pushed, it is
2420 possible for the evaluation of a parm to clobber
2421 something we have already written to the stack.
2422 Since most function calls on RISC machines do not use
2423 the stack, this is uncommon, but must work correctly.
2425 Therefore, we save any area of the stack that was already
2426 written and that we are using. Here we set up to do this
2427 by making a new stack usage map from the old one. The
2428 actual save will be done by store_one_arg.
2430 Another approach might be to try to reorder the argument
2431 evaluations to avoid this conflicting stack usage. */
2433 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2434 /* Since we will be writing into the entire argument area,
2435 the map must be allocated for its entire size, not just
2436 the part that is the responsibility of the caller. */
2438 #endif
2440 #ifdef ARGS_GROW_DOWNWARD
2443 #else
2445 needed);
2446 #endif
2454 initial_highest_arg_in_use);
2458 (highest_outgoing_arg_in_use
2462 /* The address of the outgoing argument list must not be
2463 copied to a register here, because argblock would be left
2464 pointing to the wrong place after the call to
2465 allocate_dynamic_stack_space below. */
2468 }
2469 else
2470 {
2472 {
2473 /* Try to reuse some or all of the pending_stack_adjust
2474 to get this space. */
2475 needed
2476 = (combine_pending_stack_adjustment_and_call
2479 preferred_unit_stack_boundary));
2481 /* combine_pending_stack_adjustment_and_call computes
2482 an adjustment before the arguments are allocated.
2483 Account for them and see whether or not the stack
2484 needs to go up or down. */
2488 {
2489 /* We're releasing stack space. */
2490 /* ??? We can avoid any adjustment at all if we're
2491 already aligned. FIXME. */
2495 }
2496 else
2497 /* We need to allocate space. We'll do that in
2498 push_block below. */
2500 }
2502 /* Special case this because overhead of `push_block' in
2503 this case is non-trivial. */
2506 else
2507 {
2509 #ifdef ARGS_GROW_DOWNWARD
2511 #endif
2512 }
2514 /* We only really need to call `copy_to_reg' in the case
2515 where push insns are going to be used to pass ARGBLOCK
2516 to a function call in ARGS. In that case, the stack
2517 pointer changes value from the allocation point to the
2518 call point, and hence the value of
2519 VIRTUAL_OUTGOING_ARGS_RTX changes as well. But might
2520 as well always do it. */
2522 }
2523 }
2524 }
2527 {
2528 /* The save/restore code in store_one_arg handles all
2529 cases except one: a constructor call (including a C
2530 function returning a BLKmode struct) to initialize
2531 an argument. */
2533 {
2534 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2537 #else
2539 #endif
2541 {
2543 NULL_RTX);
2547 /* stack_arg_under_construction says whether a stack
2548 arg is being constructed at the old stack level.
2549 Pushing the stack gets a clean outgoing argument
2550 block. */
2551 old_stack_arg_under_construction
2554 /* Make a new map for the new argument list. */
2560 }
2562 BITS_PER_UNIT);
2563 }
2565 /* If argument evaluation might modify the stack pointer,
2566 copy the address of the argument list to a register. */
2569 {
2572 }
2573 }
2577 /* If we push args individually in reverse order, perform stack alignment
2578 before the first push (the last arg). */
2581 {
2582 /* When the stack adjustment is pending, we get better code
2583 by combining the adjustments. */
2587 {
2588 pending_stack_adjust
2589 = (combine_pending_stack_adjustment_and_call
2592 preferred_unit_stack_boundary));
2594 }
2598 }
2599 /* Now that the stack is properly aligned, pops can't safely
2600 be deferred during the evaluation of the arguments. */
2601 NO_DEFER_POP;
2605 /* Figure out the register where the value, if any, will come back. */
2609 {
2613 else
2617 /* If VALREG is a PARALLEL whose first member has a zero
2618 offset, use that. This is for targets such as m68k that
2619 return the same value in multiple places. */
2621 {
2628 }
2629 }
2631 /* Precompute all register parameters. It isn't safe to compute anything
2632 once we have started filling any specific hard regs. */
2637 else
2640 #ifdef REG_PARM_STACK_SPACE
2641 /* Save the fixed argument area if it's part of the caller's frame and
2642 is clobbered by argument setup for this call. */
2646 #endif
2648 /* Now store (and compute if necessary) all non-register parms.
2649 These come before register parms, since they can require block-moves,
2650 which could clobber the registers used for register parms.
2651 Parms which have partial registers are not stored here,
2652 but we do preallocate space here if they want that. */
2656 {
2661 reg_parm_stack_space)
2673 call_fusage);
2674 }
2676 /* If we have a parm that is passed in registers but not in memory
2677 and whose alignment does not permit a direct copy into registers,
2678 make a group of pseudos that correspond to each register that we
2679 will later fill. */
2683 /* Now store any partially-in-registers parm.
2684 This is the last place a block-move can happen. */
2688 {
2693 reg_parm_stack_space)
2698 }
2700 /* If we pushed args in forward order, perform stack alignment
2701 after pushing the last arg. */
2706 /* If register arguments require space on the stack and stack space
2707 was not preallocated, allocate stack space here for arguments
2708 passed in registers. */
2709 #ifdef OUTGOING_REG_PARM_STACK_SPACE
2713 #endif
2715 /* Pass the function the address in which to return a
2716 structure value. */
2718 {
2719 structure_value_addr
2724 NULL_RTX)));
2728 }
2736 /* Save a pointer to the last insn before the call, so that we can
2737 later safely search backwards to find the CALL_INSN. */
2740 /* Set up next argument register. For sibling calls on machines
2741 with register windows this should be the incoming register. */
2742 #ifdef FUNCTION_INCOMING_ARG
2746 else
2747 #endif
2751 /* All arguments and registers used for the call must be set up by
2752 now! */
2754 /* Stack must be properly aligned now. */
2758 /* Generate the actual call instruction. */
2764 /* If a non-BLKmode value is returned at the most significant end
2765 of a register, shift the register right by the appropriate amount
2766 and update VALREG accordingly. BLKmode values are handled by the
2767 group load/store machinery below. */
2769 && !pcc_struct_value
2772 {
2776 }
2778 /* If call is cse'able, make appropriate pair of reg-notes around it.
2779 Test valreg so we don't crash; may safely ignore `const'
2780 if return type is void. Disable for PARALLEL return values, because
2781 we have no way to move such values into a pseudo register. */
2783 {
2784 rtx insns;
2785 rtx insn;
2790 /* Expansion of block moves possibly introduced a loop that may
2791 not appear inside libcall block. */
2797 {
2800 }
2801 else
2802 {
2806 /* Mark the return value as a pointer if needed. */
2813 && fndecl
2821 else
2822 {
2823 /* Construct an "equal form" for the value which
2824 mentions all the arguments in order as well as
2825 the function name. */
2836 note);
2837 }
2841 }
2842 }
2844 {
2848 /* The return value from a malloc-like function is a pointer. */
2854 /* The return value from a malloc-like function can not alias
2855 anything else. */
2860 /* Write out the sequence. */
2865 }
2867 /* For calls to `setjmp', etc., inform flow.c it should complain
2868 if nonvolatile values are live. For functions that cannot return,
2869 inform flow that control does not fall through. */
2872 {
2873 /* The barrier must be emitted
2874 immediately after the CALL_INSN. Some ports emit more
2875 than just a CALL_INSN above, so we must search for it here. */
2879 {
2881 /* There was no CALL_INSN? */
2883 }
2887 /* Stack adjustments after a noreturn call are dead code.
2888 However when NO_DEFER_POP is in effect, we must preserve
2889 stack_pointer_delta. */
2891 {
2894 }
2895 }
2897 /* If value type not void, return an rtx for the value. */
2903 {
2905 {
2906 target
2909 structure_value_addr));
2911 }
2912 }
2914 {
2915 /* This is the special C++ case where we need to
2916 know what the true target was. We take care to
2917 never use this value more than once in one expression. */
2921 }
2922 /* Handle calls that return values in multiple non-contiguous locations.
2923 The Irix 6 ABI has examples of this. */
2925 {
2927 {
2928 /* This will only be assigned once, so it can be readonly. */
2934 }
2940 /* We can not support sibling calls for this case. */
2942 }
2946 {
2949 /* We have to copy a return value in a CLASS_LIKELY_SPILLED hard
2950 reg to a plain register. */
2957 /* If TARGET is a MEM in the argument area, and we have
2958 saved part of the argument area, then we can't store
2959 directly into TARGET as it may get overwritten when we
2960 restore the argument save area below. Don't work too
2961 hard though and simply force TARGET to a register if it
2962 is a MEM; the optimizer is quite likely to sort it out. */
2966 {
2969 }
2973 else
2974 {
2975 /* TARGET and VALREG cannot be equal at this point
2976 because the latter would not have
2977 REG_FUNCTION_VALUE_P true, while the former would if
2978 it were referring to the same register.
2980 If they refer to the same register, this move will be
2981 a no-op, except when function inlining is being
2982 done. */
2985 /* If we are setting a MEM, this code must be executed.
2986 Since it is emitted after the call insn, sibcall
2987 optimization cannot be performed in that case. */
2990 }
2991 }
2993 {
2996 /* We can not support sibling calls for this case. */
2998 }
2999 else
3003 {
3004 /* If we promoted this return value, make the proper SUBREG.
3005 TARGET might be const0_rtx here, so be careful. */
3009 {
3016 /* If we don't promote as expected, something is wrong. */
3022 {
3029 }
3033 }
3034 }
3036 /* If size of args is variable or this was a constructor call for a stack
3037 argument, restore saved stack-pointer value. */
3040 {
3049 }
3051 {
3052 #ifdef REG_PARM_STACK_SPACE
3056 #endif
3058 /* If we saved any argument areas, restore them. */
3061 {
3063 rtx stack_area
3070 else
3073 BLOCK_OP_CALL_PARM);
3074 }
3078 }
3080 /* If this was alloca, record the new stack level for nonlocal gotos.
3081 Check for the handler slots since we might not have a save area
3082 for non-local gotos. */
3087 /* Free up storage we no longer need. */
3096 {
3099 /* Restore the pending stack adjustment now that we have
3100 finished generating the sibling call sequence. */
3105 /* Prepare arg structure for next iteration. */
3107 {
3111 }
3114 }
3115 else
3116 {
3119 /* Verify that we've deallocated all the stack we used. */
3121 || (old_stack_allocated
3123 }
3125 /* If something prevents making this a sibling call,
3126 zero out the sequence. */
3129 else
3131 }
3133 /* If tail call production succeeded, we need to remove REG_EQUIV notes on
3134 arguments too, as argument area is now clobbered by the call. */
3136 {
3139 }
3140 else
3143 currently_expanding_call--;
3145 /* If this function returns with the stack pointer depressed, ensure
3146 this block saves and restores the stack pointer, show it was
3147 changed, and adjust for any outgoing arg space. */
3149 {
3153 }
3159 }
3161 /* A sibling call sequence invalidates any REG_EQUIV notes made for
3162 this function's incoming arguments.
3164 At the start of RTL generation we know the only REG_EQUIV notes
3165 in the rtl chain are those for incoming arguments, so we can look
3166 for REG_EQUIV notes between the start of the function and the
3167 NOTE_INSN_FUNCTION_BEG.
3169 This is (slight) overkill. We could keep track of the highest
3170 argument we clobber and be more selective in removing notes, but it
3171 does not seem to be worth the effort. */
3173 void
3175 {
3176 rtx insn;
3179 {
3180 rtx note;
3182 /* There are never REG_EQUIV notes for the incoming arguments
3183 after the NOTE_INSN_FUNCTION_BEG note, so stop if we see it. */
3193 }
3194 }
3196 /* Traverse a list of TYPES and expand all complex types into their
3197 components. */
3198 static tree
3200 {
3201 tree p;
3203 /* Before allocating memory, check for the common case of no complex. */
3205 {
3210 }
3213 found:
3217 {
3222 {
3225 /* Rewrite complex type with component type. */
3229 /* Add another component type for the imaginary part. */
3234 /* Skip the newly created node. */
3236 }
3237 }
3240 }
3241 \f
3242 /* Output a library call to function FUN (a SYMBOL_REF rtx).
3243 The RETVAL parameter specifies whether return value needs to be saved, other
3244 parameters are documented in the emit_library_call function below. */
3246 static rtx
3250 {
3251 /* Total size in bytes of all the stack-parms scanned so far. */
3253 /* Size of arguments before any adjustments (such as rounding). */
3256 rtx fun;
3260 CUMULATIVE_ARGS args_so_far;
3261 struct arg
3262 {
3263 rtx value;
3265 rtx reg;
3268 rtx save_area;
3269 };
3274 rtx valreg;
3280 rtx before_call;
3283 #ifdef REG_PARM_STACK_SPACE
3284 /* Define the boundary of the register parm stack space that needs to be
3285 save, if any. */
3288 #endif
3290 /* Size of the stack reserved for parameter registers. */
3297 #ifdef REG_PARM_STACK_SPACE
3299 #endif
3301 /* By default, library functions can not throw. */
3305 {
3329 }
3332 /* Ensure current function's preferred stack boundary is at least
3333 what we need. */
3337 /* If this kind of value comes back in memory,
3338 decide where in memory it should come back. */
3340 {
3343 {
3344 #ifdef PCC_STATIC_STRUCT_RETURN
3345 rtx pointer_reg
3355 else
3357 #endif
3358 /* This call returns a big structure. */
3360 }
3361 }
3362 else
3365 /* ??? Unfinished: must pass the memory address as an argument. */
3367 /* Copy all the libcall-arguments out of the varargs data
3368 and into a vector ARGVEC.
3370 Compute how to pass each argument. We only support a very small subset
3371 of the full argument passing conventions to limit complexity here since
3372 library functions shouldn't have many args. */
3377 #ifdef INIT_CUMULATIVE_LIBCALL_ARGS
3379 #else
3381 #endif
3388 /* Now we are about to start emitting insns that can be deleted
3389 if a libcall is deleted. */
3395 /* If there's a structure value address to be passed,
3396 either pass it in the special place, or pass it as an extra argument. */
3398 {
3401 nargs++;
3403 /* Make sure it is a reasonable operand for a move or push insn. */
3417 #ifdef STACK_PARMS_IN_REG_PARM_AREA
3419 #else
3421 #endif
3430 count++;
3431 }
3434 {
3438 /* We cannot convert the arg value to the mode the library wants here;
3439 must do it earlier where we know the signedness of the arg. */
3443 /* Make sure it is a reasonable operand for a move or push insn. */
3449 {
3450 rtx slot;
3451 int must_copy
3454 /* loop.c won't look at CALL_INSN_FUNCTION_USAGE of const/pure
3455 functions, so we have to pretend this isn't such a function. */
3457 {
3461 }
3464 /* If this was a CONST function, it is now PURE since
3465 it now reads memory. */
3467 {
3470 }
3474 else
3475 {
3479 }
3483 call_fusage);
3487 slot),
3488 call_fusage);
3492 }
3503 #ifdef STACK_PARMS_IN_REG_PARM_AREA
3505 #else
3507 #endif
3518 }
3520 /* If this machine requires an external definition for library
3521 functions, write one out. */
3526 + stack_pointer_delta
3528 / STACK_BYTES
3533 reg_parm_stack_space);
3535 #ifndef OUTGOING_REG_PARM_STACK_SPACE
3537 #endif
3543 {
3544 /* Since the stack pointer will never be pushed, it is possible for
3545 the evaluation of a parm to clobber something we have already
3546 written to the stack. Since most function calls on RISC machines
3547 do not use the stack, this is uncommon, but must work correctly.
3549 Therefore, we save any area of the stack that was already written
3550 and that we are using. Here we set up to do this by making a new
3551 stack usage map from the old one.
3553 Another approach might be to try to reorder the argument
3554 evaluations to avoid this conflicting stack usage. */
3558 #ifndef OUTGOING_REG_PARM_STACK_SPACE
3559 /* Since we will be writing into the entire argument area, the
3560 map must be allocated for its entire size, not just the part that
3561 is the responsibility of the caller. */
3563 #endif
3565 #ifdef ARGS_GROW_DOWNWARD
3568 #else
3570 needed);
3571 #endif
3577 initial_highest_arg_in_use);
3584 /* We must be careful to use virtual regs before they're instantiated,
3585 and real regs afterwards. Loop optimization, for example, can create
3586 new libcalls after we've instantiated the virtual regs, and if we
3587 use virtuals anyway, they won't match the rtl patterns. */
3591 else
3593 }
3594 else
3595 {
3598 }
3600 /* If we push args individually in reverse order, perform stack alignment
3601 before the first push (the last arg). */
3607 {
3610 }
3611 else
3612 {
3615 }
3617 #ifdef REG_PARM_STACK_SPACE
3619 {
3620 /* The argument list is the property of the called routine and it
3621 may clobber it. If the fixed area has been used for previous
3622 parameters, we must save and restore it. */
3625 }
3626 #endif
3628 /* Push the args that need to be pushed. */
3630 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
3631 are to be pushed. */
3633 {
3641 {
3643 {
3644 /* If this is being stored into a pre-allocated, fixed-size,
3645 stack area, save any previous data at that location. */
3647 #ifdef ARGS_GROW_DOWNWARD
3648 /* stack_slot is negative, but we want to index stack_usage_map
3649 with positive values. */
3652 #else
3655 #endif
3658 /* Don't worry about things in the fixed argument area;
3659 it has already been saved. */
3663 i++;
3666 {
3667 /* We need to make a save area. */
3668 unsigned int size
3670 enum machine_mode save_mode
3672 rtx adr
3675 rtx stack_area
3679 {
3686 stack_area,
3688 BLOCK_OP_CALL_PARM);
3689 }
3690 else
3691 {
3695 }
3696 }
3697 }
3702 reg_parm_stack_space,
3705 /* Now mark the segment we just used. */
3710 NO_DEFER_POP;
3713 {
3714 rtx use;
3716 /* Indicate argument access so that alias.c knows that these
3717 values are live. */
3721 else
3722 /* When arguments are pushed, trying to tell alias.c where
3723 exactly this argument is won't work, because the
3724 auto-increment causes confusion. So we merely indicate
3725 that we access something with a known mode somewhere on
3726 the stack. */
3732 }
3733 }
3734 }
3736 /* If we pushed args in forward order, perform stack alignment
3737 after pushing the last arg. */
3744 else
3749 /* Now load any reg parms into their regs. */
3751 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
3752 are to be pushed. */
3754 {
3760 /* Handle calls that pass values in multiple non-contiguous
3761 locations. The PA64 has examples of this for library calls. */
3767 NO_DEFER_POP;
3768 }
3770 /* Any regs containing parms remain in use through the call. */
3772 {
3777 {
3780 {
3785 }
3786 else
3788 }
3789 }
3791 /* Pass the function the address in which to return a structure value. */
3793 {
3797 NULL_RTX)));
3800 }
3802 /* Don't allow popping to be deferred, since then
3803 cse'ing of library calls could delete a call and leave the pop. */
3804 NO_DEFER_POP;
3808 /* Stack must be properly aligned now. */
3814 /* We pass the old value of inhibit_defer_pop + 1 to emit_call_1, which
3815 will set inhibit_defer_pop to that value. */
3816 /* The return type is needed to decide how many bytes the function pops.
3817 Signedness plays no role in that, so for simplicity, we pretend it's
3818 always signed. We also assume that the list of arguments passed has
3819 no impact, so we pretend it is unknown. */
3825 struct_value_size,
3827 valreg,
3830 /* For calls to `setjmp', etc., inform flow.c it should complain
3831 if nonvolatile values are live. For functions that cannot return,
3832 inform flow that control does not fall through. */
3835 {
3836 /* The barrier note must be emitted
3837 immediately after the CALL_INSN. Some ports emit more than
3838 just a CALL_INSN above, so we must search for it here. */
3842 {
3844 /* There was no CALL_INSN? */
3846 }
3849 }
3851 /* Now restore inhibit_defer_pop to its actual original value. */
3852 OK_DEFER_POP;
3854 /* If call is cse'able, make appropriate pair of reg-notes around it.
3855 Test valreg so we don't crash; may safely ignore `const'
3856 if return type is void. Disable for PARALLEL return values, because
3857 we have no way to move such values into a pseudo register. */
3859 {
3860 rtx insns;
3863 {
3867 }
3868 else
3869 {
3871 rtx temp;
3875 {
3880 }
3884 /* Construct an "equal form" for the value which mentions all the
3885 arguments in order as well as the function name. */
3898 note);
3903 }
3904 }
3907 /* Copy the value to the right place. */
3909 {
3911 {
3916 }
3918 {
3922 }
3923 else
3924 {
3925 /* Convert to the proper mode if PROMOTE_MODE has been active. */
3927 {
3935 }
3939 else
3941 }
3942 }
3945 {
3946 #ifdef REG_PARM_STACK_SPACE
3950 #endif
3952 /* If we saved any argument areas, restore them. */
3955 {
3966 BLOCK_OP_CALL_PARM);
3967 else
3969 }
3973 }
3980 }
3981 \f
3982 /* Output a library call to function FUN (a SYMBOL_REF rtx)
3983 (emitting the queue unless NO_QUEUE is nonzero),
3984 for a value of mode OUTMODE,
3985 with NARGS different arguments, passed as alternating rtx values
3986 and machine_modes to convert them to.
3988 FN_TYPE should be LCT_NORMAL for `normal' calls, LCT_CONST for `const'
3989 calls, LCT_PURE for `pure' calls, LCT_CONST_MAKE_BLOCK for `const' calls
3990 which should be enclosed in REG_LIBCALL/REG_RETVAL notes,
3991 LCT_PURE_MAKE_BLOCK for `purep' calls which should be enclosed in
3992 REG_LIBCALL/REG_RETVAL notes with extra (use (memory (scratch)),
3993 or other LCT_ value for other types of library calls. */
3995 void
3998 {
4004 }
4005 \f
4006 /* Like emit_library_call except that an extra argument, VALUE,
4007 comes second and says where to store the result.
4008 (If VALUE is zero, this function chooses a convenient way
4009 to return the value.
4011 This function returns an rtx for where the value is to be found.
4012 If VALUE is nonzero, VALUE is returned. */
4014 rtx
4018 {
4019 rtx result;
4028 }
4029 \f
4030 /* Store a single argument for a function call
4031 into the register or memory area where it must be passed.
4032 *ARG describes the argument value and where to pass it.
4034 ARGBLOCK is the address of the stack-block for all the arguments,
4035 or 0 on a machine where arguments are pushed individually.
4037 MAY_BE_ALLOCA nonzero says this could be a call to `alloca'
4038 so must be careful about how the stack is used.
4040 VARIABLE_SIZE nonzero says that this was a variable-sized outgoing
4041 argument stack. This is used if ACCUMULATE_OUTGOING_ARGS to indicate
4042 that we need not worry about saving and restoring the stack.
4044 FNDECL is the declaration of the function we are calling.
4046 Return nonzero if this arg should cause sibcall failure,
4047 zero otherwise. */
4049 static int
4052 {
4063 /* Push a new temporary level for any temporaries we make for
4064 this argument. */
4068 {
4069 /* If this is being stored into a pre-allocated, fixed-size, stack area,
4070 save any previous data at that location. */
4072 {
4073 #ifdef ARGS_GROW_DOWNWARD
4074 /* stack_slot is negative, but we want to index stack_usage_map
4075 with positive values. */
4078 else
4082 #else
4085 else
4089 #endif
4092 /* Don't worry about things in the fixed argument area;
4093 it has already been saved. */
4097 i++;
4100 {
4101 /* We need to make a save area. */
4108 {
4117 BLOCK_OP_CALL_PARM);
4118 }
4119 else
4120 {
4123 }
4124 }
4125 }
4126 }
4128 /* If this isn't going to be placed on both the stack and in registers,
4129 set up the register and number of words. */
4131 {
4134 else
4137 }
4139 /* Being passed entirely in a register. We shouldn't be called in
4140 this case. */
4143 /* If this arg needs special alignment, don't load the registers
4144 here. */
4148 /* If this is being passed partially in a register, we can't evaluate
4149 it directly into its stack slot. Otherwise, we can. */
4151 {
4152 /* stack_arg_under_construction is nonzero if a function argument is
4153 being evaluated directly into the outgoing argument list and
4154 expand_call must take special action to preserve the argument list
4155 if it is called recursively.
4157 For scalar function arguments stack_usage_map is sufficient to
4158 determine which stack slots must be saved and restored. Scalar
4159 arguments in general have pass_on_stack == 0.
4161 If this argument is initialized by a function which takes the
4162 address of the argument (a C++ constructor or a C function
4163 returning a BLKmode structure), then stack_usage_map is
4164 insufficient and expand_call must push the stack around the
4165 function call. Such arguments have pass_on_stack == 1.
4167 Note that it is always safe to set stack_arg_under_construction,
4168 but this generates suboptimal code if set when not needed. */
4171 stack_arg_under_construction++;
4174 (partial
4179 /* If we are promoting object (or for any other reason) the mode
4180 doesn't agree, convert the mode. */
4187 stack_arg_under_construction--;
4188 }
4190 /* Check for overlap with already clobbered argument area. */
4197 /* Don't allow anything left on stack from computation
4198 of argument to alloca. */
4203 /* If the value is already in the stack slot, we are done. */
4204 ;
4206 {
4210 /* Argument is a scalar, not entirely passed in registers.
4211 (If part is passed in registers, arg->partial says how much
4212 and emit_push_insn will take care of putting it there.)
4214 Push it, and if its size is less than the
4215 amount of space allocated to it,
4216 also bump stack pointer by the additional space.
4217 Note that in C the default argument promotions
4218 will prevent such mismatches. */
4221 /* Compute how much space the push instruction will push.
4222 On many machines, pushing a byte will advance the stack
4223 pointer by a halfword. */
4224 #ifdef PUSH_ROUNDING
4226 #endif
4229 /* Compute how much space the argument should get:
4230 round up to a multiple of the alignment for arguments. */
4236 /* Compute the alignment of the pushed argument. */
4239 {
4242 {
4245 }
4246 }
4248 /* This isn't already where we want it on the stack, so put it there.
4249 This can either be done with push or copy insns. */
4255 /* Unless this is a partially-in-register argument, the argument is now
4256 in the stack. */
4259 }
4260 else
4261 {
4262 /* BLKmode, at least partly to be pushed. */
4266 rtx size_rtx;
4268 /* Pushing a nonscalar.
4269 If part is passed in registers, PARTIAL says how much
4270 and emit_push_insn will take care of putting it there. */
4272 /* Round its size up to a multiple
4273 of the allocation unit for arguments. */
4276 {
4279 }
4280 else
4281 {
4282 /* PUSH_ROUNDING has no effect on us, because emit_push_insn
4283 for BLKmode is careful to avoid it. */
4289 }
4293 /* When an argument is padded down, the block is aligned to
4294 PARM_BOUNDARY, but the actual argument isn't. */
4296 {
4300 {
4303 }
4304 }
4307 {
4308 /* emit_push_insn might not work properly if arg->value and
4309 argblock + arg->locate.offset areas overlap. */
4316 current_function_internal_arg_pointer
4318 {
4322 /* expand_call should ensure this. */
4327 {
4330 }
4332 {
4335 }
4336 }
4337 }
4344 /* Unless this is a partially-in-register argument, the argument is now
4345 in the stack.
4347 ??? Unlike the case above, in which we want the actual
4348 address of the data, so that we can load it directly into a
4349 register, here we want the address of the stack slot, so that
4350 it's properly aligned for word-by-word copying or something
4351 like that. It's not clear that this is always correct. */
4354 }
4357 {
4359 arg->parallel_value
4362 }
4364 /* Mark all slots this store used. */
4370 /* Once we have pushed something, pops can't safely
4371 be deferred during the rest of the arguments. */
4372 NO_DEFER_POP;
4374 /* Free any temporary slots made in processing this argument. Show
4375 that we might have taken the address of something and pushed that
4376 as an operand. */
4382 }
4384 /* Nonzero if we do not know how to pass TYPE solely in registers. */
4386 bool
4388 tree type)
4389 {
4393 /* If the type has variable size... */
4397 /* If the type is marked as addressable (it is required
4398 to be constructed into the stack)... */
4403 }
4405 /* Another version of the TARGET_MUST_PASS_IN_STACK hook. This one
4406 takes trailing padding of a structure into account. */
4407 /* ??? Should be able to merge these two by examining BLOCK_REG_PADDING. */
4409 bool
4411 {
4415 /* If the type has variable size... */
4419 /* If the type is marked as addressable (it is required
4420 to be constructed into the stack)... */
4424 /* If the padding and mode of the type is such that a copy into
4425 a register would put it into the wrong part of the register. */
4433 }