| blob | 2d68f7507a50450d520792c8586762d32290d163 |
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 3, 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 COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
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 /* The area corresponding to register parameters is not to count in
1226 the size of the block we need. So make the adjustment. */
1228 args_size->var
1231 }
1232 }
1233 else
1234 {
1239 + stack_pointer_delta
1241 / preferred_stack_boundary
1246 reg_parm_stack_space);
1250 }
1252 }
1254 /* Precompute parameters as needed for a function call.
1256 FLAGS is mask of ECF_* constants.
1258 NUM_ACTUALS is the number of arguments.
1260 ARGS is an array containing information for each argument; this
1261 routine fills in the INITIAL_VALUE and VALUE fields for each
1262 precomputed argument. */
1264 static void
1266 {
1269 /* If this is a libcall, then precompute all arguments so that we do not
1270 get extraneous instructions emitted as part of the libcall sequence. */
1272 /* If we preallocated the stack space, and some arguments must be passed
1273 on the stack, then we must precompute any parameter which contains a
1274 function call which will store arguments on the stack.
1275 Otherwise, evaluating the parameter may clobber previous parameters
1276 which have already been stored into the stack. (we have code to avoid
1277 such case by saving the outgoing stack arguments, but it results in
1278 worse code) */
1283 {
1290 /* If this is an addressable type, we cannot pre-evaluate it. */
1298 {
1302 #if defined(PROMOTE_FUNCTION_MODE) && !defined(PROMOTE_MODE)
1303 /* CSE will replace this only if it contains args[i].value
1304 pseudo, so convert it down to the declared mode using
1305 a SUBREG. */
1308 {
1314 }
1315 #endif
1316 }
1317 }
1318 }
1320 /* Given the current state of MUST_PREALLOCATE and information about
1321 arguments to a function call in NUM_ACTUALS, ARGS and ARGS_SIZE,
1322 compute and return the final value for MUST_PREALLOCATE. */
1324 static int
1327 {
1328 /* See if we have or want to preallocate stack space.
1330 If we would have to push a partially-in-regs parm
1331 before other stack parms, preallocate stack space instead.
1333 If the size of some parm is not a multiple of the required stack
1334 alignment, we must preallocate.
1336 If the total size of arguments that would otherwise create a copy in
1337 a temporary (such as a CALL) is more than half the total argument list
1338 size, preallocation is faster.
1340 Another reason to preallocate is if we have a machine (like the m88k)
1341 where stack alignment is required to be maintained between every
1342 pair of insns, not just when the call is made. However, we assume here
1343 that such machines either do not have push insns (and hence preallocation
1344 would occur anyway) or the problem is taken care of with
1345 PUSH_ROUNDING. */
1348 {
1354 {
1365 copy_to_evaluate_size
1367 }
1372 }
1374 }
1376 /* If we preallocated stack space, compute the address of each argument
1377 and store it into the ARGS array.
1379 We need not ensure it is a valid memory address here; it will be
1380 validized when it is used.
1382 ARGBLOCK is an rtx for the address of the outgoing arguments. */
1384 static void
1386 {
1388 {
1396 {
1399 rtx addr;
1404 /* Skip this parm if it will not be passed on the stack. */
1412 else
1418 {
1419 /* Only part of the parameter is being passed on the stack.
1420 Generate a simple memory reference of the correct size. */
1426 }
1427 else
1428 {
1432 }
1438 {
1441 }
1446 else
1452 {
1453 /* Only part of the parameter is being passed on the stack.
1454 Generate a simple memory reference of the correct size.
1455 */
1458 }
1459 else
1460 {
1464 }
1467 /* Function incoming arguments may overlap with sibling call
1468 outgoing arguments and we cannot allow reordering of reads
1469 from function arguments with stores to outgoing arguments
1470 of sibling calls. */
1473 }
1474 }
1475 }
1477 /* Given a FNDECL and EXP, return an rtx suitable for use as a target address
1478 in a call instruction.
1480 FNDECL is the tree node for the target function. For an indirect call
1481 FNDECL will be NULL_TREE.
1483 ADDR is the operand 0 of CALL_EXPR for this call. */
1485 static rtx
1487 {
1488 rtx funexp;
1490 /* Get the function to call, in the form of RTL. */
1492 {
1493 /* If this is the first use of the function, see if we need to
1494 make an external definition for it. */
1496 {
1499 }
1501 /* Get a SYMBOL_REF rtx for the function address. */
1503 }
1504 else
1505 /* Generate an rtx (probably a pseudo-register) for the address. */
1506 {
1510 }
1512 }
1514 /* Return true if and only if SIZE storage units (usually bytes)
1515 starting from address ADDR overlap with already clobbered argument
1516 area. This function is used to determine if we should give up a
1517 sibcall. */
1519 static bool
1521 {
1522 HOST_WIDE_INT i;
1530 /* Return true for arg pointer based indexed addressing. */
1535 else
1538 #ifdef ARGS_GROW_DOWNWARD
1540 #endif
1542 {
1549 }
1552 }
1554 /* Do the register loads required for any wholly-register parms or any
1555 parms which are passed both on the stack and in a register. Their
1556 expressions were already evaluated.
1558 Mark all register-parms as living through the call, putting these USE
1559 insns in the CALL_INSN_FUNCTION_USAGE field.
1561 When IS_SIBCALL, perform the check_sibcall_argument_overlap
1562 checking, setting *SIBCALL_FAILURE if appropriate. */
1564 static void
1568 {
1572 {
1576 {
1581 /* Set non-negative if we must move a word at a time, even if
1582 just one word (e.g, partial == 4 && mode == DFmode). Set
1583 to -1 if we just use a normal move insn. This value can be
1584 zero if the argument is a zero size structure. */
1587 ;
1589 {
1592 }
1594 {
1597 }
1598 else
1601 /* Handle calls that pass values in multiple non-contiguous
1602 locations. The Irix 6 ABI has examples of this. */
1607 /* If simple case, just do move. If normal partial, store_one_arg
1608 has already loaded the register for us. In all other cases,
1609 load the register(s) from memory. */
1612 {
1614 #ifdef BLOCK_REG_PADDING
1615 /* Handle case where we have a value that needs shifting
1616 up to the msb. eg. a QImode value and we're padding
1617 upward on a BYTES_BIG_ENDIAN machine. */
1621 {
1622 rtx x;
1625 /* Assigning REG here rather than a temp makes CALL_FUSAGE
1626 report the whole reg as used. Strictly speaking, the
1627 call only uses SIZE bytes at the msb end, but it doesn't
1628 seem worth generating rtl to say that. */
1635 }
1636 #endif
1637 }
1639 /* If we have pre-computed the values to put in the registers in
1640 the case of non-aligned structures, copy them in now. */
1648 {
1651 /* Check for overlap with already clobbered argument area. */
1654 size))
1657 /* Handle a BLKmode that needs shifting. */
1659 #ifdef BLOCK_REG_PADDING
1661 #else
1662 && BYTES_BIG_ENDIAN
1663 #endif
1664 )
1665 {
1679 }
1680 else
1682 }
1684 /* When a parameter is a block, and perhaps in other cases, it is
1685 possible that it did a load from an argument slot that was
1686 already clobbered. */
1691 /* Handle calls that pass values in multiple non-contiguous
1692 locations. The Irix 6 ABI has examples of this. */
1699 }
1700 }
1701 }
1703 /* We need to pop PENDING_STACK_ADJUST bytes. But, if the arguments
1704 wouldn't fill up an even multiple of PREFERRED_UNIT_STACK_BOUNDARY
1705 bytes, then we would need to push some additional bytes to pad the
1706 arguments. So, we compute an adjust to the stack pointer for an
1707 amount that will leave the stack under-aligned by UNADJUSTED_ARGS_SIZE
1708 bytes. Then, when the arguments are pushed the stack will be perfectly
1709 aligned. ARGS_SIZE->CONSTANT is set to the number of bytes that should
1710 be popped after the call. Returns the adjustment. */
1712 static int
1716 {
1717 /* The number of bytes to pop so that the stack will be
1718 under-aligned by UNADJUSTED_ARGS_SIZE bytes. */
1719 HOST_WIDE_INT adjustment;
1720 /* The alignment of the stack after the arguments are pushed, if we
1721 just pushed the arguments without adjust the stack here. */
1724 unadjusted_alignment
1728 /* We want to get rid of as many of the PENDING_STACK_ADJUST bytes
1729 as possible -- leaving just enough left to cancel out the
1730 UNADJUSTED_ALIGNMENT. In other words, we want to ensure that the
1731 PENDING_STACK_ADJUST is non-negative, and congruent to
1732 -UNADJUSTED_ALIGNMENT modulo the PREFERRED_UNIT_STACK_BOUNDARY. */
1734 /* Begin by trying to pop all the bytes. */
1735 unadjusted_alignment
1736 = (unadjusted_alignment
1739 /* Push enough additional bytes that the stack will be aligned
1740 after the arguments are pushed. */
1742 {
1745 else
1747 }
1749 /* Now, sets ARGS_SIZE->CONSTANT so that we pop the right number of
1750 bytes after the call. The right number is the entire
1751 PENDING_STACK_ADJUST less our ADJUSTMENT plus the amount required
1752 by the arguments in the first place. */
1753 args_size->constant
1757 }
1759 /* Scan X expression if it does not dereference any argument slots
1760 we already clobbered by tail call arguments (as noted in stored_args_map
1761 bitmap).
1762 Return nonzero if X expression dereferences such argument slots,
1763 zero otherwise. */
1765 static int
1767 {
1768 RTX_CODE code;
1781 /* Scan all subexpressions. */
1784 {
1786 {
1789 }
1791 {
1795 }
1796 }
1798 }
1800 /* Scan sequence after INSN if it does not dereference any argument slots
1801 we already clobbered by tail call arguments (as noted in stored_args_map
1802 bitmap). If MARK_STORED_ARGS_MAP, add stack slots for ARG to
1803 stored_args_map bitmap afterwards (when ARG is a register MARK_STORED_ARGS_MAP
1804 should be 0). Return nonzero if sequence after INSN dereferences such argument
1805 slots, zero otherwise. */
1807 static int
1809 {
1814 else
1823 {
1824 #ifdef ARGS_GROW_DOWNWARD
1826 #else
1828 #endif
1832 }
1834 }
1836 /* Given that a function returns a value of mode MODE at the most
1837 significant end of hard register VALUE, shift VALUE left or right
1838 as specified by LEFT_P. Return true if some action was needed. */
1840 bool
1842 {
1843 HOST_WIDE_INT shift;
1850 /* Use ashr rather than lshr for right shifts. This is for the benefit
1851 of the MIPS port, which requires SImode values to be sign-extended
1852 when stored in 64-bit registers. */
1857 }
1859 /* If X is a likely-spilled register value, copy it to a pseudo
1860 register and return that register. Return X otherwise. */
1862 static rtx
1864 {
1870 {
1871 /* Make sure that we generate a REG rather than a CONCAT.
1872 Moves into CONCATs can need nontrivial instructions,
1873 and the whole point of this function is to avoid
1874 using the hard register directly in such a situation. */
1880 }
1882 }
1884 /* Generate all the code for a CALL_EXPR exp
1885 and return an rtx for its value.
1886 Store the value in TARGET (specified as an rtx) if convenient.
1887 If the value is stored in TARGET then TARGET is returned.
1888 If IGNORE is nonzero, then we ignore the value of the function call. */
1890 rtx
1892 {
1893 /* Nonzero if we are currently expanding a call. */
1896 /* RTX for the function to be called. */
1897 rtx funexp;
1898 /* Sequence of insns to perform a normal "call". */
1900 /* Sequence of insns to perform a tail "call". */
1902 /* Data type of the function. */
1903 tree funtype;
1904 tree type_arg_types;
1905 /* Declaration of the function being called,
1906 or 0 if the function is computed (not known by name). */
1908 /* The type of the function being called. */
1909 tree fntype;
1913 /* Register in which non-BLKmode value will be returned,
1914 or 0 if no value or if value is BLKmode. */
1915 rtx valreg;
1916 /* Address where we should return a BLKmode value;
1917 0 if value not BLKmode. */
1919 /* Nonzero if that address is being passed by treating it as
1920 an extra, implicit first parameter. Otherwise,
1921 it is passed by being copied directly into struct_value_rtx. */
1923 /* Holds the value of implicit argument for the struct value. */
1925 /* Size of aggregate value wanted, or zero if none wanted
1926 or if we are using the non-reentrant PCC calling convention
1927 or expecting the value in registers. */
1929 /* Nonzero if called function returns an aggregate in memory PCC style,
1930 by returning the address of where to find it. */
1934 /* Number of actual parameters in this call, including struct value addr. */
1936 /* Number of named args. Args after this are anonymous ones
1937 and they must all go on the stack. */
1939 /* Number of complex actual arguments that need to be split. */
1942 /* Vector of information about each argument.
1943 Arguments are numbered in the order they will be pushed,
1944 not the order they are written. */
1947 /* Total size in bytes of all the stack-parms scanned so far. */
1950 /* Size of arguments before any adjustments (such as rounding). */
1952 /* Data on reg parms scanned so far. */
1953 CUMULATIVE_ARGS args_so_far;
1954 /* Nonzero if a reg parm has been scanned. */
1956 /* Nonzero if this is an indirect function call. */
1958 /* Nonzero if we must avoid push-insns in the args for this call.
1959 If stack space is allocated for register parameters, but not by the
1960 caller, then it is preallocated in the fixed part of the stack frame.
1961 So the entire argument block must then be preallocated (i.e., we
1962 ignore PUSH_ROUNDING in that case). */
1966 /* Size of the stack reserved for parameter registers. */
1969 /* Address of space preallocated for stack parms
1970 (on machines that lack push insns), or 0 if space not preallocated. */
1973 /* Mask of ECF_ flags. */
1975 #ifdef REG_PARM_STACK_SPACE
1976 /* Define the boundary of the register parm stack space that needs to be
1977 saved, if any. */
1980 #endif
1988 /* State variables to track stack modifications. */
1994 /* Some stack pointer alterations we make are performed via
1995 allocate_dynamic_stack_space. This modifies the stack_pointer_delta,
1996 which we then also need to save/restore along the way. */
1999 rtx call_fusage;
2003 /* The alignment of the stack, in bits. */
2005 /* The alignment of the stack, in bytes. */
2007 /* The static chain value to use for this call. */
2008 rtx static_chain_value;
2009 /* See if this is "nothrow" function call. */
2013 /* See if we can find a DECL-node for the actual function, and get the
2014 function attributes (flags) from the function decl or type node. */
2017 {
2020 }
2021 else
2022 {
2025 }
2029 /* Warn if this value is an aggregate type,
2030 regardless of which calling convention we are using for it. */
2034 /* If the result of a pure or const function call is ignored (or void),
2035 and none of its arguments are volatile, we can avoid expanding the
2036 call and just evaluate the arguments for side-effects. */
2040 {
2042 tree arg;
2043 call_expr_arg_iterator iter;
2047 {
2050 }
2053 {
2057 }
2058 }
2060 #ifdef REG_PARM_STACK_SPACE
2062 #endif
2067 /* Set up a place to return a structure. */
2069 /* Cater to broken compilers. */
2071 {
2072 /* This call returns a big structure. */
2075 #ifdef PCC_STATIC_STRUCT_RETURN
2076 {
2078 }
2080 {
2085 else
2086 {
2087 /* For variable-sized objects, we must be called with a target
2088 specified. If we were to allocate space on the stack here,
2089 we would have no way of knowing when to free it. */
2095 }
2096 }
2098 }
2100 /* Figure out the amount to which the stack should be aligned. */
2103 {
2107 }
2109 /* Operand 0 is a pointer-to-function; get the type of the function. */
2114 /* Count whether there are actual complex arguments that need to be split
2115 into their real and imaginary parts. Munge the type_arg_types
2116 appropriately here as well. */
2118 {
2119 call_expr_arg_iterator iter;
2120 tree arg;
2122 {
2126 num_complex_actuals++;
2127 }
2129 }
2130 else
2136 /* If struct_value_rtx is 0, it means pass the address
2137 as if it were an extra parameter. Put the argument expression
2138 in structure_value_addr_value. */
2140 {
2141 /* If structure_value_addr is a REG other than
2142 virtual_outgoing_args_rtx, we can use always use it. If it
2143 is not a REG, we must always copy it into a register.
2144 If it is virtual_outgoing_args_rtx, we must copy it to another
2145 register in some cases. */
2147 || (ACCUMULATE_OUTGOING_ARGS
2148 && stack_arg_under_construction
2154 structure_value_addr_value =
2157 }
2159 /* Count the arguments and set NUM_ACTUALS. */
2160 num_actuals =
2163 /* Compute number of named args.
2164 First, do a raw count of the args for INIT_CUMULATIVE_ARGS. */
2167 n_named_args
2169 /* Count the struct value address, if it is passed as a parm. */
2171 else
2172 /* If we know nothing, treat all args as named. */
2175 /* Start updating where the next arg would go.
2177 On some machines (such as the PA) indirect calls have a different
2178 calling convention than normal calls. The fourth argument in
2179 INIT_CUMULATIVE_ARGS tells the backend if this is an indirect call
2180 or not. */
2183 /* Now possibly adjust the number of named args.
2184 Normally, don't include the last named arg if anonymous args follow.
2185 We do include the last named arg if
2186 targetm.calls.strict_argument_naming() returns nonzero.
2187 (If no anonymous args follow, the result of list_length is actually
2188 one too large. This is harmless.)
2190 If targetm.calls.pretend_outgoing_varargs_named() returns
2191 nonzero, and targetm.calls.strict_argument_naming() returns zero,
2192 this machine will be able to place unnamed args that were passed
2193 in registers into the stack. So treat all args as named. This
2194 allows the insns emitting for a specific argument list to be
2195 independent of the function declaration.
2197 If targetm.calls.pretend_outgoing_varargs_named() returns zero,
2198 we do not have any reliable way to pass unnamed args in
2199 registers, so we must force them into memory. */
2203 ;
2206 /* Don't include the last named arg. */
2208 else
2209 /* Treat all args as named. */
2212 /* Make a vector to hold all the information about each arg. */
2216 /* Build up entries in the ARGS array, compute the size of the
2217 arguments into ARGS_SIZE, etc. */
2227 {
2228 /* If this function requires a variable-sized argument list, don't
2229 try to make a cse'able block for this call. We may be able to
2230 do this eventually, but it is too complicated to keep track of
2231 what insns go in the cse'able block and which don't. */
2235 }
2237 /* Now make final decision about preallocating stack space. */
2242 /* If the structure value address will reference the stack pointer, we
2243 must stabilize it. We don't need to do this if we know that we are
2244 not going to adjust the stack pointer in processing this call. */
2249 structure_value_addr))
2254 /* Tail calls can make things harder to debug, and we've traditionally
2255 pushed these optimizations into -O2. Don't try if we're already
2256 expanding a call, as that means we're an argument. Don't try if
2257 there's cleanups, as we know there's code to follow the call. */
2260 || !flag_optimize_sibling_calls
2266 /* Rest of purposes for tail call optimizations to fail. */
2268 #ifdef HAVE_sibcall_epilogue
2269 !HAVE_sibcall_epilogue
2270 #else
2271 1
2272 #endif
2273 || !try_tail_call
2274 /* Doing sibling call optimization needs some work, since
2275 structure_value_addr can be allocated on the stack.
2276 It does not seem worth the effort since few optimizable
2277 sibling calls will return a structure. */
2279 /* Check whether the target is able to optimize the call
2280 into a sibcall. */
2282 /* Functions that do not return exactly once may not be sibcall
2283 optimized. */
2286 /* If the called function is nested in the current one, it might access
2287 some of the caller's arguments, but could clobber them beforehand if
2288 the argument areas are shared. */
2290 /* If this function requires more stack slots than the current
2291 function, we cannot change it into a sibling call.
2292 current_function_pretend_args_size is not part of the
2293 stack allocated by our caller. */
2296 /* If the callee pops its own arguments, then it must pop exactly
2297 the same number of arguments as the current function. */
2301 current_function_args_size))
2305 /* Ensure current function's preferred stack boundary is at least
2306 what we need. We don't have to increase alignment for recursive
2307 functions. */
2316 /* We want to make two insn chains; one for a sibling call, the other
2317 for a normal call. We will select one of the two chains after
2318 initial RTL generation is complete. */
2320 {
2322 /* We want to emit any pending stack adjustments before the tail
2323 recursion "call". That way we know any adjustment after the tail
2324 recursion call can be ignored if we indeed use the tail
2325 call expansion. */
2328 rtx insns;
2332 {
2333 /* State variables we need to save and restore between
2334 iterations. */
2337 }
2340 else
2343 /* Other state variables that we must reinitialize each time
2344 through the loop (that are not initialized by the loop itself). */
2348 /* Start a new sequence for the normal call case.
2350 From this point on, if the sibling call fails, we want to set
2351 sibcall_failure instead of continuing the loop. */
2354 /* Don't let pending stack adjusts add up to too much.
2355 Also, do all pending adjustments now if there is any chance
2356 this might be a call to alloca or if we are expanding a sibling
2357 call sequence or if we are calling a function that is to return
2358 with stack pointer depressed.
2359 Also do the adjustments before a throwing call, otherwise
2360 exception handling can fail; PR 19225. */
2369 /* When calling a const function, we must pop the stack args right away,
2370 so that the pop is deleted or moved with the call. */
2372 NO_DEFER_POP;
2374 /* Precompute any arguments as needed. */
2378 /* Now we are about to start emitting insns that can be deleted
2379 if a libcall is deleted. */
2387 /* Compute the actual size of the argument block required. The variable
2388 and constant sizes must be combined, the size may have to be rounded,
2389 and there may be a minimum required size. When generating a sibcall
2390 pattern, do not round up, since we'll be re-using whatever space our
2391 caller provided. */
2392 unadjusted_args_size
2400 /* The argument block when performing a sibling call is the
2401 incoming argument block. */
2403 {
2405 argblock
2406 #ifdef STACK_GROWS_DOWNWARD
2408 #else
2410 #endif
2413 }
2415 /* If we have no actual push instructions, or shouldn't use them,
2416 make space for all args right now. */
2418 {
2420 {
2425 /* stack_arg_under_construction says whether a stack arg is
2426 being constructed at the old stack level. Pushing the stack
2427 gets a clean outgoing argument block. */
2430 }
2432 }
2433 else
2434 {
2435 /* Note that we must go through the motions of allocating an argument
2436 block even if the size is zero because we may be storing args
2437 in the area reserved for register arguments, which may be part of
2438 the stack frame. */
2442 /* Store the maximum argument space used. It will be pushed by
2443 the prologue (if ACCUMULATE_OUTGOING_ARGS, or stack overflow
2444 checking). */
2450 {
2452 {
2453 /* Since the stack pointer will never be pushed, it is
2454 possible for the evaluation of a parm to clobber
2455 something we have already written to the stack.
2456 Since most function calls on RISC machines do not use
2457 the stack, this is uncommon, but must work correctly.
2459 Therefore, we save any area of the stack that was already
2460 written and that we are using. Here we set up to do this
2461 by making a new stack usage map from the old one. The
2462 actual save will be done by store_one_arg.
2464 Another approach might be to try to reorder the argument
2465 evaluations to avoid this conflicting stack usage. */
2467 /* Since we will be writing into the entire argument area,
2468 the map must be allocated for its entire size, not just
2469 the part that is the responsibility of the caller. */
2473 #ifdef ARGS_GROW_DOWNWARD
2476 #else
2478 needed);
2479 #endif
2487 initial_highest_arg_in_use);
2491 (highest_outgoing_arg_in_use
2495 /* The address of the outgoing argument list must not be
2496 copied to a register here, because argblock would be left
2497 pointing to the wrong place after the call to
2498 allocate_dynamic_stack_space below. */
2501 }
2502 else
2503 {
2505 {
2506 /* Try to reuse some or all of the pending_stack_adjust
2507 to get this space. */
2508 needed
2509 = (combine_pending_stack_adjustment_and_call
2512 preferred_unit_stack_boundary));
2514 /* combine_pending_stack_adjustment_and_call computes
2515 an adjustment before the arguments are allocated.
2516 Account for them and see whether or not the stack
2517 needs to go up or down. */
2521 {
2522 /* We're releasing stack space. */
2523 /* ??? We can avoid any adjustment at all if we're
2524 already aligned. FIXME. */
2528 }
2529 else
2530 /* We need to allocate space. We'll do that in
2531 push_block below. */
2533 }
2535 /* Special case this because overhead of `push_block' in
2536 this case is non-trivial. */
2539 else
2540 {
2542 #ifdef ARGS_GROW_DOWNWARD
2544 #endif
2545 }
2547 /* We only really need to call `copy_to_reg' in the case
2548 where push insns are going to be used to pass ARGBLOCK
2549 to a function call in ARGS. In that case, the stack
2550 pointer changes value from the allocation point to the
2551 call point, and hence the value of
2552 VIRTUAL_OUTGOING_ARGS_RTX changes as well. But might
2553 as well always do it. */
2555 }
2556 }
2557 }
2560 {
2561 /* The save/restore code in store_one_arg handles all
2562 cases except one: a constructor call (including a C
2563 function returning a BLKmode struct) to initialize
2564 an argument. */
2566 {
2567 rtx push_size
2572 {
2574 NULL_RTX);
2578 /* stack_arg_under_construction says whether a stack
2579 arg is being constructed at the old stack level.
2580 Pushing the stack gets a clean outgoing argument
2581 block. */
2582 old_stack_arg_under_construction
2585 /* Make a new map for the new argument list. */
2591 }
2593 BITS_PER_UNIT);
2594 }
2596 /* If argument evaluation might modify the stack pointer,
2597 copy the address of the argument list to a register. */
2600 {
2603 }
2604 }
2608 /* If we push args individually in reverse order, perform stack alignment
2609 before the first push (the last arg). */
2612 {
2613 /* When the stack adjustment is pending, we get better code
2614 by combining the adjustments. */
2618 {
2619 pending_stack_adjust
2620 = (combine_pending_stack_adjustment_and_call
2623 preferred_unit_stack_boundary));
2625 }
2629 }
2630 /* Now that the stack is properly aligned, pops can't safely
2631 be deferred during the evaluation of the arguments. */
2632 NO_DEFER_POP;
2636 /* Figure out the register where the value, if any, will come back. */
2640 {
2644 else
2648 /* If VALREG is a PARALLEL whose first member has a zero
2649 offset, use that. This is for targets such as m68k that
2650 return the same value in multiple places. */
2652 {
2659 }
2660 }
2662 /* Precompute all register parameters. It isn't safe to compute anything
2663 once we have started filling any specific hard regs. */
2668 else
2671 #ifdef REG_PARM_STACK_SPACE
2672 /* Save the fixed argument area if it's part of the caller's frame and
2673 is clobbered by argument setup for this call. */
2677 #endif
2679 /* Now store (and compute if necessary) all non-register parms.
2680 These come before register parms, since they can require block-moves,
2681 which could clobber the registers used for register parms.
2682 Parms which have partial registers are not stored here,
2683 but we do preallocate space here if they want that. */
2687 {
2692 reg_parm_stack_space)
2704 call_fusage);
2705 }
2707 /* If we have a parm that is passed in registers but not in memory
2708 and whose alignment does not permit a direct copy into registers,
2709 make a group of pseudos that correspond to each register that we
2710 will later fill. */
2714 /* Now store any partially-in-registers parm.
2715 This is the last place a block-move can happen. */
2719 {
2724 reg_parm_stack_space)
2729 }
2731 /* If we pushed args in forward order, perform stack alignment
2732 after pushing the last arg. */
2737 /* If register arguments require space on the stack and stack space
2738 was not preallocated, allocate stack space here for arguments
2739 passed in registers. */
2744 /* Pass the function the address in which to return a
2745 structure value. */
2747 {
2748 structure_value_addr
2753 NULL_RTX)));
2757 }
2766 /* Save a pointer to the last insn before the call, so that we can
2767 later safely search backwards to find the CALL_INSN. */
2770 /* Set up next argument register. For sibling calls on machines
2771 with register windows this should be the incoming register. */
2772 #ifdef FUNCTION_INCOMING_ARG
2776 else
2777 #endif
2781 /* All arguments and registers used for the call must be set up by
2782 now! */
2784 /* Stack must be properly aligned now. */
2788 /* Generate the actual call instruction. */
2794 /* If the call setup or the call itself overlaps with anything
2795 of the argument setup we probably clobbered our call address.
2796 In that case we can't do sibcalls. */
2801 /* If a non-BLKmode value is returned at the most significant end
2802 of a register, shift the register right by the appropriate amount
2803 and update VALREG accordingly. BLKmode values are handled by the
2804 group load/store machinery below. */
2806 && !pcc_struct_value
2809 {
2813 }
2815 /* If call is cse'able, make appropriate pair of reg-notes around it.
2816 Test valreg so we don't crash; may safely ignore `const'
2817 if return type is void. Disable for PARALLEL return values, because
2818 we have no way to move such values into a pseudo register. */
2820 {
2821 rtx insns;
2822 rtx insn;
2827 /* Expansion of block moves possibly introduced a loop that may
2828 not appear inside libcall block. */
2834 {
2837 }
2838 else
2839 {
2843 /* Mark the return value as a pointer if needed. */
2850 && fndecl
2858 else
2859 {
2860 /* Construct an "equal form" for the value which
2861 mentions all the arguments in order as well as
2862 the function name. */
2873 note);
2874 }
2878 }
2879 }
2881 {
2885 /* The return value from a malloc-like function is a pointer. */
2891 /* The return value from a malloc-like function can not alias
2892 anything else. */
2897 /* Write out the sequence. */
2902 }
2904 /* For calls to `setjmp', etc., inform
2905 function.c:setjmp_warnings that it should complain if
2906 nonvolatile values are live. For functions that cannot
2907 return, inform flow that control does not fall through. */
2910 {
2911 /* The barrier must be emitted
2912 immediately after the CALL_INSN. Some ports emit more
2913 than just a CALL_INSN above, so we must search for it here. */
2917 {
2919 /* There was no CALL_INSN? */
2921 }
2925 /* Stack adjustments after a noreturn call are dead code.
2926 However when NO_DEFER_POP is in effect, we must preserve
2927 stack_pointer_delta. */
2929 {
2932 }
2933 }
2935 /* If value type not void, return an rtx for the value. */
2941 {
2943 {
2944 target
2947 structure_value_addr));
2949 }
2950 }
2952 {
2953 /* This is the special C++ case where we need to
2954 know what the true target was. We take care to
2955 never use this value more than once in one expression. */
2959 }
2960 /* Handle calls that return values in multiple non-contiguous locations.
2961 The Irix 6 ABI has examples of this. */
2963 {
2965 {
2966 /* This will only be assigned once, so it can be readonly. */
2972 }
2978 /* We can not support sibling calls for this case. */
2980 }
2984 {
2987 /* We have to copy a return value in a CLASS_LIKELY_SPILLED hard
2988 reg to a plain register. */
2992 /* If TARGET is a MEM in the argument area, and we have
2993 saved part of the argument area, then we can't store
2994 directly into TARGET as it may get overwritten when we
2995 restore the argument save area below. Don't work too
2996 hard though and simply force TARGET to a register if it
2997 is a MEM; the optimizer is quite likely to sort it out. */
3001 {
3004 }
3008 else
3009 {
3010 /* TARGET and VALREG cannot be equal at this point
3011 because the latter would not have
3012 REG_FUNCTION_VALUE_P true, while the former would if
3013 it were referring to the same register.
3015 If they refer to the same register, this move will be
3016 a no-op, except when function inlining is being
3017 done. */
3020 /* If we are setting a MEM, this code must be executed.
3021 Since it is emitted after the call insn, sibcall
3022 optimization cannot be performed in that case. */
3025 }
3026 }
3028 {
3031 /* We can not support sibling calls for this case. */
3033 }
3034 else
3038 {
3039 /* If we promoted this return value, make the proper SUBREG.
3040 TARGET might be const0_rtx here, so be careful. */
3044 {
3051 /* If we don't promote as expected, something is wrong. */
3057 {
3064 }
3068 }
3069 }
3071 /* If size of args is variable or this was a constructor call for a stack
3072 argument, restore saved stack-pointer value. */
3075 {
3084 }
3086 {
3087 #ifdef REG_PARM_STACK_SPACE
3091 #endif
3093 /* If we saved any argument areas, restore them. */
3096 {
3098 rtx stack_area
3105 else
3108 BLOCK_OP_CALL_PARM);
3109 }
3113 }
3115 /* If this was alloca, record the new stack level for nonlocal gotos.
3116 Check for the handler slots since we might not have a save area
3117 for non-local gotos. */
3122 /* Free up storage we no longer need. */
3131 {
3134 /* Restore the pending stack adjustment now that we have
3135 finished generating the sibling call sequence. */
3140 /* Prepare arg structure for next iteration. */
3142 {
3146 }
3149 }
3150 else
3151 {
3154 /* Verify that we've deallocated all the stack we used. */
3156 || (old_stack_allocated
3158 }
3160 /* If something prevents making this a sibling call,
3161 zero out the sequence. */
3164 else
3166 }
3168 /* If tail call production succeeded, we need to remove REG_EQUIV notes on
3169 arguments too, as argument area is now clobbered by the call. */
3171 {
3174 }
3175 else
3178 currently_expanding_call--;
3180 /* If this function returns with the stack pointer depressed, ensure
3181 this block saves and restores the stack pointer, show it was
3182 changed, and adjust for any outgoing arg space. */
3184 {
3188 }
3194 }
3196 /* A sibling call sequence invalidates any REG_EQUIV notes made for
3197 this function's incoming arguments.
3199 At the start of RTL generation we know the only REG_EQUIV notes
3200 in the rtl chain are those for incoming arguments, so we can look
3201 for REG_EQUIV notes between the start of the function and the
3202 NOTE_INSN_FUNCTION_BEG.
3204 This is (slight) overkill. We could keep track of the highest
3205 argument we clobber and be more selective in removing notes, but it
3206 does not seem to be worth the effort. */
3208 void
3210 {
3211 rtx insn;
3214 {
3215 rtx note;
3217 /* There are never REG_EQUIV notes for the incoming arguments
3218 after the NOTE_INSN_FUNCTION_BEG note, so stop if we see it. */
3228 }
3229 }
3231 /* Traverse a list of TYPES and expand all complex types into their
3232 components. */
3233 static tree
3235 {
3236 tree p;
3238 /* Before allocating memory, check for the common case of no complex. */
3240 {
3245 }
3248 found:
3252 {
3257 {
3260 /* Rewrite complex type with component type. */
3264 /* Add another component type for the imaginary part. */
3269 /* Skip the newly created node. */
3271 }
3272 }
3275 }
3276 \f
3277 /* Output a library call to function FUN (a SYMBOL_REF rtx).
3278 The RETVAL parameter specifies whether return value needs to be saved, other
3279 parameters are documented in the emit_library_call function below. */
3281 static rtx
3285 {
3286 /* Total size in bytes of all the stack-parms scanned so far. */
3288 /* Size of arguments before any adjustments (such as rounding). */
3291 rtx fun;
3295 CUMULATIVE_ARGS args_so_far;
3296 struct arg
3297 {
3298 rtx value;
3300 rtx reg;
3303 rtx save_area;
3304 };
3309 rtx valreg;
3315 rtx before_call;
3318 #ifdef REG_PARM_STACK_SPACE
3319 /* Define the boundary of the register parm stack space that needs to be
3320 save, if any. */
3323 #endif
3325 /* Size of the stack reserved for parameter registers. */
3332 #ifdef REG_PARM_STACK_SPACE
3334 #endif
3336 /* By default, library functions can not throw. */
3340 {
3364 }
3367 /* Ensure current function's preferred stack boundary is at least
3368 what we need. */
3372 /* If this kind of value comes back in memory,
3373 decide where in memory it should come back. */
3375 {
3378 {
3379 #ifdef PCC_STATIC_STRUCT_RETURN
3380 rtx pointer_reg
3390 else
3392 #endif
3393 /* This call returns a big structure. */
3395 }
3396 }
3397 else
3400 /* ??? Unfinished: must pass the memory address as an argument. */
3402 /* Copy all the libcall-arguments out of the varargs data
3403 and into a vector ARGVEC.
3405 Compute how to pass each argument. We only support a very small subset
3406 of the full argument passing conventions to limit complexity here since
3407 library functions shouldn't have many args. */
3412 #ifdef INIT_CUMULATIVE_LIBCALL_ARGS
3414 #else
3416 #endif
3423 /* Now we are about to start emitting insns that can be deleted
3424 if a libcall is deleted. */
3430 /* If there's a structure value address to be passed,
3431 either pass it in the special place, or pass it as an extra argument. */
3433 {
3436 nargs++;
3438 /* Make sure it is a reasonable operand for a move or push insn. */
3452 #ifdef STACK_PARMS_IN_REG_PARM_AREA
3454 #else
3456 #endif
3465 count++;
3466 }
3469 {
3473 /* We cannot convert the arg value to the mode the library wants here;
3474 must do it earlier where we know the signedness of the arg. */
3478 /* Make sure it is a reasonable operand for a move or push insn. */
3484 {
3485 rtx slot;
3486 int must_copy
3489 /* loop.c won't look at CALL_INSN_FUNCTION_USAGE of const/pure
3490 functions, so we have to pretend this isn't such a function. */
3492 {
3496 }
3499 /* If this was a CONST function, it is now PURE since
3500 it now reads memory. */
3502 {
3505 }
3509 else
3510 {
3514 }
3518 call_fusage);
3522 slot),
3523 call_fusage);
3527 }
3538 #ifdef STACK_PARMS_IN_REG_PARM_AREA
3540 #else
3542 #endif
3553 }
3555 /* If this machine requires an external definition for library
3556 functions, write one out. */
3561 + stack_pointer_delta
3563 / STACK_BYTES
3568 reg_parm_stack_space);
3577 {
3578 /* Since the stack pointer will never be pushed, it is possible for
3579 the evaluation of a parm to clobber something we have already
3580 written to the stack. Since most function calls on RISC machines
3581 do not use the stack, this is uncommon, but must work correctly.
3583 Therefore, we save any area of the stack that was already written
3584 and that we are using. Here we set up to do this by making a new
3585 stack usage map from the old one.
3587 Another approach might be to try to reorder the argument
3588 evaluations to avoid this conflicting stack usage. */
3592 /* Since we will be writing into the entire argument area, the
3593 map must be allocated for its entire size, not just the part that
3594 is the responsibility of the caller. */
3598 #ifdef ARGS_GROW_DOWNWARD
3601 #else
3603 needed);
3604 #endif
3610 initial_highest_arg_in_use);
3617 /* We must be careful to use virtual regs before they're instantiated,
3618 and real regs afterwards. Loop optimization, for example, can create
3619 new libcalls after we've instantiated the virtual regs, and if we
3620 use virtuals anyway, they won't match the rtl patterns. */
3624 else
3626 }
3627 else
3628 {
3631 }
3633 /* If we push args individually in reverse order, perform stack alignment
3634 before the first push (the last arg). */
3640 {
3643 }
3644 else
3645 {
3648 }
3650 #ifdef REG_PARM_STACK_SPACE
3652 {
3653 /* The argument list is the property of the called routine and it
3654 may clobber it. If the fixed area has been used for previous
3655 parameters, we must save and restore it. */
3658 }
3659 #endif
3661 /* Push the args that need to be pushed. */
3663 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
3664 are to be pushed. */
3666 {
3674 {
3676 {
3677 /* If this is being stored into a pre-allocated, fixed-size,
3678 stack area, save any previous data at that location. */
3680 #ifdef ARGS_GROW_DOWNWARD
3681 /* stack_slot is negative, but we want to index stack_usage_map
3682 with positive values. */
3685 #else
3688 #endif
3691 /* Don't worry about things in the fixed argument area;
3692 it has already been saved. */
3696 i++;
3699 {
3700 /* We need to make a save area. */
3701 unsigned int size
3703 enum machine_mode save_mode
3705 rtx adr
3708 rtx stack_area
3712 {
3719 stack_area,
3721 BLOCK_OP_CALL_PARM);
3722 }
3723 else
3724 {
3728 }
3729 }
3730 }
3735 reg_parm_stack_space,
3738 /* Now mark the segment we just used. */
3743 NO_DEFER_POP;
3746 {
3747 rtx use;
3749 /* Indicate argument access so that alias.c knows that these
3750 values are live. */
3754 else
3755 /* When arguments are pushed, trying to tell alias.c where
3756 exactly this argument is won't work, because the
3757 auto-increment causes confusion. So we merely indicate
3758 that we access something with a known mode somewhere on
3759 the stack. */
3765 }
3766 }
3767 }
3769 /* If we pushed args in forward order, perform stack alignment
3770 after pushing the last arg. */
3777 else
3782 /* Now load any reg parms into their regs. */
3784 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
3785 are to be pushed. */
3787 {
3793 /* Handle calls that pass values in multiple non-contiguous
3794 locations. The PA64 has examples of this for library calls. */
3800 NO_DEFER_POP;
3801 }
3803 /* Any regs containing parms remain in use through the call. */
3805 {
3810 {
3813 {
3818 }
3819 else
3821 }
3822 }
3824 /* Pass the function the address in which to return a structure value. */
3826 {
3830 NULL_RTX)));
3833 }
3835 /* Don't allow popping to be deferred, since then
3836 cse'ing of library calls could delete a call and leave the pop. */
3837 NO_DEFER_POP;
3841 /* Stack must be properly aligned now. */
3847 /* We pass the old value of inhibit_defer_pop + 1 to emit_call_1, which
3848 will set inhibit_defer_pop to that value. */
3849 /* The return type is needed to decide how many bytes the function pops.
3850 Signedness plays no role in that, so for simplicity, we pretend it's
3851 always signed. We also assume that the list of arguments passed has
3852 no impact, so we pretend it is unknown. */
3858 struct_value_size,
3860 valreg,
3863 /* For calls to `setjmp', etc., inform function.c:setjmp_warnings
3864 that it should complain if nonvolatile values are live. For
3865 functions that cannot return, inform flow that control does not
3866 fall through. */
3869 {
3870 /* The barrier note must be emitted
3871 immediately after the CALL_INSN. Some ports emit more than
3872 just a CALL_INSN above, so we must search for it here. */
3876 {
3878 /* There was no CALL_INSN? */
3880 }
3883 }
3885 /* Now restore inhibit_defer_pop to its actual original value. */
3886 OK_DEFER_POP;
3888 /* If call is cse'able, make appropriate pair of reg-notes around it.
3889 Test valreg so we don't crash; may safely ignore `const'
3890 if return type is void. Disable for PARALLEL return values, because
3891 we have no way to move such values into a pseudo register. */
3893 {
3894 rtx insns;
3897 {
3901 }
3902 else
3903 {
3905 rtx temp;
3909 {
3914 }
3918 /* Construct an "equal form" for the value which mentions all the
3919 arguments in order as well as the function name. */
3932 note);
3937 }
3938 }
3941 /* Copy the value to the right place. */
3943 {
3945 {
3950 }
3952 {
3956 }
3957 else
3958 {
3959 /* Convert to the proper mode if PROMOTE_MODE has been active. */
3961 {
3969 }
3973 else
3975 }
3976 }
3979 {
3980 #ifdef REG_PARM_STACK_SPACE
3984 #endif
3986 /* If we saved any argument areas, restore them. */
3989 {
4000 BLOCK_OP_CALL_PARM);
4001 else
4003 }
4007 }
4014 }
4015 \f
4016 /* Output a library call to function FUN (a SYMBOL_REF rtx)
4017 (emitting the queue unless NO_QUEUE is nonzero),
4018 for a value of mode OUTMODE,
4019 with NARGS different arguments, passed as alternating rtx values
4020 and machine_modes to convert them to.
4022 FN_TYPE should be LCT_NORMAL for `normal' calls, LCT_CONST for `const'
4023 calls, LCT_PURE for `pure' calls, LCT_CONST_MAKE_BLOCK for `const' calls
4024 which should be enclosed in REG_LIBCALL/REG_RETVAL notes,
4025 LCT_PURE_MAKE_BLOCK for `purep' calls which should be enclosed in
4026 REG_LIBCALL/REG_RETVAL notes with extra (use (memory (scratch)),
4027 or other LCT_ value for other types of library calls. */
4029 void
4032 {
4038 }
4039 \f
4040 /* Like emit_library_call except that an extra argument, VALUE,
4041 comes second and says where to store the result.
4042 (If VALUE is zero, this function chooses a convenient way
4043 to return the value.
4045 This function returns an rtx for where the value is to be found.
4046 If VALUE is nonzero, VALUE is returned. */
4048 rtx
4052 {
4053 rtx result;
4062 }
4063 \f
4064 /* Store a single argument for a function call
4065 into the register or memory area where it must be passed.
4066 *ARG describes the argument value and where to pass it.
4068 ARGBLOCK is the address of the stack-block for all the arguments,
4069 or 0 on a machine where arguments are pushed individually.
4071 MAY_BE_ALLOCA nonzero says this could be a call to `alloca'
4072 so must be careful about how the stack is used.
4074 VARIABLE_SIZE nonzero says that this was a variable-sized outgoing
4075 argument stack. This is used if ACCUMULATE_OUTGOING_ARGS to indicate
4076 that we need not worry about saving and restoring the stack.
4078 FNDECL is the declaration of the function we are calling.
4080 Return nonzero if this arg should cause sibcall failure,
4081 zero otherwise. */
4083 static int
4086 {
4097 /* Push a new temporary level for any temporaries we make for
4098 this argument. */
4102 {
4103 /* If this is being stored into a pre-allocated, fixed-size, stack area,
4104 save any previous data at that location. */
4106 {
4107 #ifdef ARGS_GROW_DOWNWARD
4108 /* stack_slot is negative, but we want to index stack_usage_map
4109 with positive values. */
4112 else
4116 #else
4119 else
4123 #endif
4126 /* Don't worry about things in the fixed argument area;
4127 it has already been saved. */
4131 i++;
4134 {
4135 /* We need to make a save area. */
4142 {
4151 BLOCK_OP_CALL_PARM);
4152 }
4153 else
4154 {
4157 }
4158 }
4159 }
4160 }
4162 /* If this isn't going to be placed on both the stack and in registers,
4163 set up the register and number of words. */
4165 {
4168 else
4171 }
4173 /* Being passed entirely in a register. We shouldn't be called in
4174 this case. */
4177 /* If this arg needs special alignment, don't load the registers
4178 here. */
4182 /* If this is being passed partially in a register, we can't evaluate
4183 it directly into its stack slot. Otherwise, we can. */
4185 {
4186 /* stack_arg_under_construction is nonzero if a function argument is
4187 being evaluated directly into the outgoing argument list and
4188 expand_call must take special action to preserve the argument list
4189 if it is called recursively.
4191 For scalar function arguments stack_usage_map is sufficient to
4192 determine which stack slots must be saved and restored. Scalar
4193 arguments in general have pass_on_stack == 0.
4195 If this argument is initialized by a function which takes the
4196 address of the argument (a C++ constructor or a C function
4197 returning a BLKmode structure), then stack_usage_map is
4198 insufficient and expand_call must push the stack around the
4199 function call. Such arguments have pass_on_stack == 1.
4201 Note that it is always safe to set stack_arg_under_construction,
4202 but this generates suboptimal code if set when not needed. */
4205 stack_arg_under_construction++;
4208 (partial
4213 /* If we are promoting object (or for any other reason) the mode
4214 doesn't agree, convert the mode. */
4221 stack_arg_under_construction--;
4222 }
4224 /* Check for overlap with already clobbered argument area. */
4231 /* Don't allow anything left on stack from computation
4232 of argument to alloca. */
4237 /* If the value is already in the stack slot, we are done. */
4238 ;
4240 {
4244 /* Argument is a scalar, not entirely passed in registers.
4245 (If part is passed in registers, arg->partial says how much
4246 and emit_push_insn will take care of putting it there.)
4248 Push it, and if its size is less than the
4249 amount of space allocated to it,
4250 also bump stack pointer by the additional space.
4251 Note that in C the default argument promotions
4252 will prevent such mismatches. */
4255 /* Compute how much space the push instruction will push.
4256 On many machines, pushing a byte will advance the stack
4257 pointer by a halfword. */
4258 #ifdef PUSH_ROUNDING
4260 #endif
4263 /* Compute how much space the argument should get:
4264 round up to a multiple of the alignment for arguments. */
4270 /* Compute the alignment of the pushed argument. */
4273 {
4276 {
4279 }
4280 }
4282 /* This isn't already where we want it on the stack, so put it there.
4283 This can either be done with push or copy insns. */
4289 /* Unless this is a partially-in-register argument, the argument is now
4290 in the stack. */
4293 }
4294 else
4295 {
4296 /* BLKmode, at least partly to be pushed. */
4300 rtx size_rtx;
4302 /* Pushing a nonscalar.
4303 If part is passed in registers, PARTIAL says how much
4304 and emit_push_insn will take care of putting it there. */
4306 /* Round its size up to a multiple
4307 of the allocation unit for arguments. */
4310 {
4313 }
4314 else
4315 {
4316 /* PUSH_ROUNDING has no effect on us, because emit_push_insn
4317 for BLKmode is careful to avoid it. */
4323 }
4327 /* When an argument is padded down, the block is aligned to
4328 PARM_BOUNDARY, but the actual argument isn't. */
4330 {
4334 {
4337 }
4338 }
4341 {
4342 /* emit_push_insn might not work properly if arg->value and
4343 argblock + arg->locate.offset areas overlap. */
4350 current_function_internal_arg_pointer
4352 {
4356 /* expand_call should ensure this. */
4362 {
4365 }
4367 {
4368 /* Use arg->locate.size.constant instead of size_rtx
4369 because we only care about the part of the argument
4370 on the stack. */
4374 }
4375 else
4376 {
4377 /* Even though they appear to be at the same location,
4378 if part of the outgoing argument is in registers,
4379 they aren't really at the same location. Check for
4380 this by making sure that the incoming size is the
4381 same as the outgoing size. */
4384 }
4385 }
4386 }
4393 /* Unless this is a partially-in-register argument, the argument is now
4394 in the stack.
4396 ??? Unlike the case above, in which we want the actual
4397 address of the data, so that we can load it directly into a
4398 register, here we want the address of the stack slot, so that
4399 it's properly aligned for word-by-word copying or something
4400 like that. It's not clear that this is always correct. */
4403 }
4406 {
4408 arg->parallel_value
4411 }
4413 /* Mark all slots this store used. */
4419 /* Once we have pushed something, pops can't safely
4420 be deferred during the rest of the arguments. */
4421 NO_DEFER_POP;
4423 /* Free any temporary slots made in processing this argument. Show
4424 that we might have taken the address of something and pushed that
4425 as an operand. */
4431 }
4433 /* Nonzero if we do not know how to pass TYPE solely in registers. */
4435 bool
4437 const_tree type)
4438 {
4442 /* If the type has variable size... */
4446 /* If the type is marked as addressable (it is required
4447 to be constructed into the stack)... */
4452 }
4454 /* Another version of the TARGET_MUST_PASS_IN_STACK hook. This one
4455 takes trailing padding of a structure into account. */
4456 /* ??? Should be able to merge these two by examining BLOCK_REG_PADDING. */
4458 bool
4460 {
4464 /* If the type has variable size... */
4468 /* If the type is marked as addressable (it is required
4469 to be constructed into the stack)... */
4473 /* If the padding and mode of the type is such that a copy into
4474 a register would put it into the wrong part of the register. */
4482 }