| blob | 868edfc396d8f4f2b12c40c8d5f3fef7d9887e0c |
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. */
46 /* Like PREFERRED_STACK_BOUNDARY but in units of bytes, not bits. */
47 #define STACK_BYTES (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT)
49 /* Data structure and subroutines used within expand_call. */
51 struct arg_data
52 {
53 /* Tree node for this argument. */
54 tree tree_value;
55 /* Mode for value; TYPE_MODE unless promoted. */
57 /* Current RTL value for argument, or 0 if it isn't precomputed. */
58 rtx value;
59 /* Initially-compute RTL value for argument; only for const functions. */
60 rtx initial_value;
61 /* Register to pass this argument in, 0 if passed on stack, or an
62 PARALLEL if the arg is to be copied into multiple non-contiguous
63 registers. */
64 rtx reg;
65 /* Register to pass this argument in when generating tail call sequence.
66 This is not the same register as for normal calls on machines with
67 register windows. */
68 rtx tail_call_reg;
69 /* If REG is a PARALLEL, this is a copy of VALUE pulled into the correct
70 form for emit_group_move. */
71 rtx parallel_value;
72 /* If REG was promoted from the actual mode of the argument expression,
73 indicates whether the promotion is sign- or zero-extended. */
75 /* Number of bytes to put in registers. 0 means put the whole arg
76 in registers. Also 0 if not passed in registers. */
78 /* Nonzero if argument must be passed on stack.
79 Note that some arguments may be passed on the stack
80 even though pass_on_stack is zero, just because FUNCTION_ARG says so.
81 pass_on_stack identifies arguments that *cannot* go in registers. */
83 /* Some fields packaged up for locate_and_pad_parm. */
85 /* Location on the stack at which parameter should be stored. The store
86 has already been done if STACK == VALUE. */
87 rtx stack;
88 /* Location on the stack of the start of this argument slot. This can
89 differ from STACK if this arg pads downward. This location is known
90 to be aligned to FUNCTION_ARG_BOUNDARY. */
91 rtx stack_slot;
92 /* Place that this stack area has been saved, if needed. */
93 rtx save_area;
94 /* If an argument's alignment does not permit direct copying into registers,
95 copy in smaller-sized pieces into pseudos. These are stored in a
96 block pointed to by this field. The next field says how many
97 word-sized pseudos we made. */
100 };
102 /* A vector of one char per byte of stack space. A byte if nonzero if
103 the corresponding stack location has been used.
104 This vector is used to prevent a function call within an argument from
105 clobbering any stack already set up. */
108 /* Size of STACK_USAGE_MAP. */
111 /* A bitmap of virtual-incoming stack space. Bit is set if the corresponding
112 stack location's tail call argument has been already stored into the stack.
113 This bitmap is used to prevent sibling call optimization if function tries
114 to use parent's incoming argument slots when they have been already
115 overwritten with tail call arguments. */
118 /* stack_arg_under_construction is nonzero when an argument may be
119 initialized with a constructor call (including a C function that
120 returns a BLKmode struct) and expand_call must take special action
121 to make sure the object being constructed does not overlap the
122 argument list for the constructor call. */
127 CUMULATIVE_ARGS *);
155 #ifdef REG_PARM_STACK_SPACE
158 #endif
159 \f
160 /* Force FUNEXP into a form suitable for the address of a CALL,
161 and return that as an rtx. Also load the static chain register
162 if FNDECL is a nested function.
164 CALL_FUSAGE points to a variable holding the prospective
165 CALL_INSN_FUNCTION_USAGE information. */
167 rtx
170 {
171 /* Make a valid memory address and copy constants through pseudo-regs,
172 but not for a constant address if -fno-function-cse. */
174 /* If we are using registers for parameters, force the
175 function address into a register now. */
180 {
181 #ifndef NO_FUNCTION_CSE
184 #endif
185 }
188 {
194 }
197 }
199 /* Generate instructions to call function FUNEXP,
200 and optionally pop the results.
201 The CALL_INSN is the first insn generated.
203 FNDECL is the declaration node of the function. This is given to the
204 macro RETURN_POPS_ARGS to determine whether this function pops its own args.
206 FUNTYPE is the data type of the function. This is given to the macro
207 RETURN_POPS_ARGS to determine whether this function pops its own args.
208 We used to allow an identifier for library functions, but that doesn't
209 work when the return type is an aggregate type and the calling convention
210 says that the pointer to this aggregate is to be popped by the callee.
212 STACK_SIZE is the number of bytes of arguments on the stack,
213 ROUNDED_STACK_SIZE is that number rounded up to
214 PREFERRED_STACK_BOUNDARY; zero if the size is variable. This is
215 both to put into the call insn and to generate explicit popping
216 code if necessary.
218 STRUCT_VALUE_SIZE is the number of bytes wanted in a structure value.
219 It is zero if this call doesn't want a structure value.
221 NEXT_ARG_REG is the rtx that results from executing
222 FUNCTION_ARG (args_so_far, VOIDmode, void_type_node, 1)
223 just after all the args have had their registers assigned.
224 This could be whatever you like, but normally it is the first
225 arg-register beyond those used for args in this call,
226 or 0 if all the arg-registers are used in this call.
227 It is passed on to `gen_call' so you can put this info in the call insn.
229 VALREG is a hard register in which a value is returned,
230 or 0 if the call does not return a value.
232 OLD_INHIBIT_DEFER_POP is the value that `inhibit_defer_pop' had before
233 the args to this call were processed.
234 We restore `inhibit_defer_pop' to that value.
236 CALL_FUSAGE is either empty or an EXPR_LIST of USE expressions that
237 denote registers used by the called function. */
239 static void
241 tree funtype ATTRIBUTE_UNUSED,
242 HOST_WIDE_INT stack_size ATTRIBUTE_UNUSED,
243 HOST_WIDE_INT rounded_stack_size,
244 HOST_WIDE_INT struct_value_size ATTRIBUTE_UNUSED,
248 {
250 rtx call_insn;
253 #if defined (HAVE_call) && defined (HAVE_call_value)
254 rtx struct_value_size_rtx;
256 #endif
258 #ifdef CALL_POPS_ARGS
260 #endif
262 /* Ensure address is valid. SYMBOL_REF is already valid, so no need,
263 and we don't want to load it into a register as an optimization,
264 because prepare_call_address already did it if it should be done. */
268 #if defined (HAVE_sibcall_pop) && defined (HAVE_sibcall_value_pop)
272 {
274 rtx pat;
276 /* If this subroutine pops its own args, record that in the call insn
277 if possible, for the sake of frame pointer elimination. */
283 n_pop);
284 else
290 }
291 else
292 #endif
294 #if defined (HAVE_call_pop) && defined (HAVE_call_value_pop)
295 /* If the target has "call" or "call_value" insns, then prefer them
296 if no arguments are actually popped. If the target does not have
297 "call" or "call_value" insns, then we must use the popping versions
298 even if the call has no arguments to pop. */
299 #if defined (HAVE_call) && defined (HAVE_call_value)
302 #else
304 #endif
305 {
307 rtx pat;
309 /* If this subroutine pops its own args, record that in the call insn
310 if possible, for the sake of frame pointer elimination. */
316 else
322 }
323 else
324 #endif
326 #if defined (HAVE_sibcall) && defined (HAVE_sibcall_value)
329 {
333 rounded_stack_size_rtx,
335 else
338 struct_value_size_rtx));
339 }
340 else
341 #endif
343 #if defined (HAVE_call) && defined (HAVE_call_value)
345 {
350 NULL_RTX));
351 else
354 struct_value_size_rtx));
355 }
356 else
357 #endif
360 /* Find the call we just emitted. */
363 /* Mark memory as used for "pure" function call. */
365 call_fusage
366 = gen_rtx_EXPR_LIST
370 call_fusage);
372 /* Put the register usage information there. */
375 /* If this is a const call, then set the insn's unchanging bit. */
379 /* If this call can't throw, attach a REG_EH_REGION reg note to that
380 effect. */
384 else
385 {
388 /* If rn < 0, then either (1) tree-ssa not used or (2) doesn't
389 throw, which we already took care of. */
394 }
401 {
405 }
409 /* Restore this now, so that we do defer pops for this call's args
410 if the context of the call as a whole permits. */
414 {
423 }
426 {
427 /* If returning from the subroutine does not automatically pop the args,
428 we need an instruction to pop them sooner or later.
429 Perhaps do it now; perhaps just record how much space to pop later.
431 If returning from the subroutine does pop the args, indicate that the
432 stack pointer will be changed. */
435 {
437 /* Just pretend we did the pop. */
442 else
444 }
445 }
446 /* When we accumulate outgoing args, we must avoid any stack manipulations.
447 Restore the stack pointer to its original value now. Usually
448 ACCUMULATE_OUTGOING_ARGS targets don't get here, but there are exceptions.
449 On i386 ACCUMULATE_OUTGOING_ARGS can be enabled on demand, and
450 popping variants of functions exist as well.
452 ??? We may optimize similar to defer_pop above, but it is
453 probably not worthwhile.
455 ??? It will be worthwhile to enable combine_stack_adjustments even for
456 such machines. */
459 }
461 /* Determine if the function identified by NAME and FNDECL is one with
462 special properties we wish to know about.
464 For example, if the function might return more than one time (setjmp), then
465 set RETURNS_TWICE to a nonzero value.
467 Similarly set NORETURN if the function is in the longjmp family.
469 Set MAY_BE_ALLOCA for any memory allocation function that might allocate
470 space from the stack such as alloca. */
472 static int
474 {
477 /* Exclude functions not at the file scope, or not `extern',
478 since they are not the magic functions we would otherwise
479 think they are.
480 FIXME: this should be handled with attributes, not with this
481 hacky imitation of DECL_ASSEMBLER_NAME. It's (also) wrong
482 because you can declare fork() inside a function if you
483 wish. */
487 {
491 /* We assume that alloca will always be called by name. It
492 makes no sense to pass it as a pointer-to-function to
493 anything that does not understand its behavior. */
502 /* Disregard prefix _, __ or __x. */
504 {
509 else
511 }
514 {
527 }
539 }
542 }
544 /* Return nonzero when FNDECL represents a call to setjmp. */
546 int
548 {
550 }
552 /* Return true when exp contains alloca call. */
553 bool
555 {
563 }
565 /* Detect flags (function attributes) from the function decl or type node. */
567 int
569 {
574 {
577 /* The function exp may have the `malloc' attribute. */
581 /* The function exp may have the `returns_twice' attribute. */
585 /* The function exp may have the `pure' attribute. */
599 }
606 /* Mark if the function returns with the stack pointer depressed. We
607 cannot consider it pure or constant in that case. */
609 {
612 }
615 }
617 /* Detect flags from a CALL_EXPR. */
619 int
621 {
627 else
628 {
632 else
634 }
637 }
639 /* Precompute all register parameters as described by ARGS, storing values
640 into fields within the ARGS array.
642 NUM_ACTUALS indicates the total number elements in the ARGS array.
644 Set REG_PARM_SEEN if we encounter a register parameter. */
646 static void
649 {
656 {
660 {
665 }
667 /* If the value is a non-legitimate constant, force it into a
668 pseudo now. TLS symbols sometimes need a call to resolve. */
673 /* If we are to promote the function arg to a wider mode,
674 do it now. */
682 /* If we're going to have to load the value by parts, pull the
683 parts into pseudos. The part extraction process can involve
684 non-trivial computation. */
686 {
691 }
693 /* If the value is expensive, and we are inside an appropriately
694 short loop, put the value into a pseudo and then put the pseudo
695 into the hard reg.
697 For small register classes, also do this if this call uses
698 register parameters. This is to avoid reload conflicts while
699 loading the parameters registers. */
709 }
710 }
712 #ifdef REG_PARM_STACK_SPACE
714 /* The argument list is the property of the called routine and it
715 may clobber it. If the fixed area has been used for previous
716 parameters, we must save and restore it. */
718 static rtx
719 save_fixed_argument_area (int reg_parm_stack_space, rtx argblock, int *low_to_save, int *high_to_save)
720 {
724 /* Compute the boundary of the area that needs to be saved, if any. */
726 #ifdef ARGS_GROW_DOWNWARD
728 #endif
734 {
738 rtx stack_area;
739 rtx save_area;
742 ;
750 /* If we don't have the required alignment, must do this
751 in BLKmode. */
756 #ifdef ARGS_GROW_DOWNWARD
758 #else
760 #endif
764 delta)));
768 {
772 }
773 else
774 {
777 }
780 }
783 }
785 static void
787 {
790 rtx stack_area;
792 #ifdef ARGS_GROW_DOWNWARD
794 #else
796 #endif
804 else
807 BLOCK_OP_CALL_PARM);
808 }
811 /* If any elements in ARGS refer to parameters that are to be passed in
812 registers, but not in memory, and whose alignment does not permit a
813 direct copy into registers. Copy the values into a group of pseudos
814 which we will later copy into the appropriate hard registers.
816 Pseudos for each unaligned argument will be stored into the array
817 args[argnum].aligned_regs. The caller is responsible for deallocating
818 the aligned_regs array if it is nonzero. */
820 static void
822 {
830 {
835 {
838 }
839 else
840 {
843 }
847 /* Structures smaller than a word are normally aligned to the
848 least significant byte. On a BYTES_BIG_ENDIAN machine,
849 this means we must skip the empty high order bytes when
850 calculating the bit offset. */
852 #ifdef BLOCK_REG_PADDING
856 #else
857 && BYTES_BIG_ENDIAN
858 #endif
859 )
863 {
872 /* There is no need to restrict this code to loading items
873 in TYPE_ALIGN sized hunks. The bitfield instructions can
874 load up entire word sized registers efficiently.
876 ??? This may not be needed anymore.
877 We use to emit a clobber here but that doesn't let later
878 passes optimize the instructions we emit. By storing 0 into
879 the register later passes know the first AND to zero out the
880 bitfield being set in the register is unnecessary. The store
881 of 0 will be deleted as will at least the first AND. */
887 word);
888 }
889 }
890 }
892 /* Fill in ARGS_SIZE and ARGS array based on the parameters found in
893 CALL_EXPR EXP.
895 NUM_ACTUALS is the total number of parameters.
897 N_NAMED_ARGS is the total number of named arguments.
899 STRUCT_VALUE_ADDR_VALUE is the implicit argument for a struct return
900 value, or null.
902 FNDECL is the tree code for the target of this call (if known)
904 ARGS_SO_FAR holds state needed by the target to know where to place
905 the next argument.
907 REG_PARM_STACK_SPACE is the number of bytes of stack space reserved
908 for arguments which are passed in registers.
910 OLD_STACK_LEVEL is a pointer to an rtx which olds the old stack level
911 and may be modified by this routine.
913 OLD_PENDING_ADJ, MUST_PREALLOCATE and FLAGS are pointers to integer
914 flags which may may be modified by this routine.
916 MAY_TAILCALL is cleared if we encounter an invisible pass-by-reference
917 that requires allocation of stack space.
919 CALL_FROM_THUNK_P is true if this call is the jump from a thunk to
920 the thunked-to function. */
922 static void
928 tree fndecl,
934 {
935 /* 1 if scanning parms front to back, -1 if scanning back to front. */
938 /* Count arg position in order args appear. */
946 /* In this loop, we consider args in the order they are written.
947 We fill up ARGS from the front or from the back if necessary
948 so that in any case the first arg to be pushed ends up at the front. */
951 {
953 /* In this case, must reverse order of args
954 so that we compute and push the last arg first. */
955 }
956 else
957 {
959 }
961 /* First fill in the actual arguments in the ARGS array, splitting
962 complex arguments if necessary. */
963 {
965 call_expr_arg_iterator iter;
966 tree arg;
969 {
972 }
974 {
977 && argtype
980 {
986 }
987 else
990 }
991 }
993 /* I counts args in order (to be) pushed; ARGPOS counts in order written. */
995 {
1000 /* Replace erroneous argument with constant zero. */
1004 /* If TYPE is a transparent union, pass things the way we would
1005 pass the first field of the union. We have already verified that
1006 the modes are the same. */
1010 /* Decide where to pass this arg.
1012 args[i].reg is nonzero if all or part is passed in registers.
1014 args[i].partial is nonzero if part but not all is passed in registers,
1015 and the exact value says how many bytes are passed in registers.
1017 args[i].pass_on_stack is nonzero if the argument must at least be
1018 computed on the stack. It may then be loaded back into registers
1019 if args[i].reg is nonzero.
1021 These decisions are driven by the FUNCTION_... macros and must agree
1022 with those made by function.c. */
1024 /* See if this argument should be passed by invisible reference. */
1027 {
1029 tree base;
1031 callee_copies
1035 /* If we're compiling a thunk, pass through invisible references
1036 instead of making a copy. */
1038 || (callee_copies
1042 {
1043 /* We can't use sibcalls if a callee-copied argument is
1044 stored in the current function's frame. */
1052 }
1053 else
1054 {
1055 /* We make a copy of the object and pass the address to the
1056 function being called. */
1057 rtx copy;
1063 STACK_CHECK_MAX_VAR_SIZE))))
1064 {
1065 /* This is a variable-sized object. Make space on the stack
1066 for it. */
1070 {
1074 }
1077 allocate_dynamic_stack_space
1080 }
1081 else
1088 else
1095 }
1096 }
1109 #ifdef FUNCTION_INCOMING_ARG
1110 /* If this is a sibling call and the machine has register windows, the
1111 register window has to be unwinded before calling the routine, so
1112 arguments have to go into the incoming registers. */
1115 #else
1117 #endif
1126 /* If FUNCTION_ARG returned a (parallel [(expr_list (nil) ...) ...]),
1127 it means that we are to pass this arg in the register(s) designated
1128 by the PARALLEL, but also to pass it in the stack. */
1133 /* If this is an addressable type, we must preallocate the stack
1134 since we must evaluate the object into its final location.
1136 If this is to be passed in both registers and the stack, it is simpler
1137 to preallocate. */
1142 /* If this is an addressable type, we cannot pre-evaluate it. Thus,
1143 we cannot consider this function call constant. */
1147 /* Compute the stack-size of this argument. */
1152 #ifdef STACK_PARMS_IN_REG_PARM_AREA
1154 #else
1156 #endif
1159 #ifdef BLOCK_REG_PADDING
1160 else
1161 /* The argument is passed entirely in registers. See at which
1162 end it should be padded. */
1166 #endif
1168 /* Update ARGS_SIZE, the total stack space for args so far. */
1174 /* Increment ARGS_SO_FAR, which has info about which arg-registers
1175 have been used, etc. */
1179 }
1180 }
1182 /* Update ARGS_SIZE to contain the total size for the argument block.
1183 Return the original constant component of the argument block's size.
1185 REG_PARM_STACK_SPACE holds the number of bytes of stack space reserved
1186 for arguments passed in registers. */
1188 static int
1192 {
1195 /* For accumulate outgoing args mode we don't need to align, since the frame
1196 will be already aligned. Align to STACK_BOUNDARY in order to prevent
1197 backends from generating misaligned frame sizes. */
1201 /* Compute the actual size of the argument block required. The variable
1202 and constant sizes must be combined, the size may have to be rounded,
1203 and there may be a minimum required size. */
1206 {
1212 {
1213 /* We don't handle this case yet. To handle it correctly we have
1214 to add the delta, round and subtract the delta.
1215 Currently no machine description requires this support. */
1218 }
1221 {
1222 args_size->var
1226 /* The area corresponding to register parameters is not to count in
1227 the size of the block we need. So make the adjustment. */
1229 args_size->var
1232 }
1233 }
1234 else
1235 {
1240 + stack_pointer_delta
1242 / preferred_stack_boundary
1247 reg_parm_stack_space);
1251 }
1253 }
1255 /* Precompute parameters as needed for a function call.
1257 FLAGS is mask of ECF_* constants.
1259 NUM_ACTUALS is the number of arguments.
1261 ARGS is an array containing information for each argument; this
1262 routine fills in the INITIAL_VALUE and VALUE fields for each
1263 precomputed argument. */
1265 static void
1267 {
1270 /* If this is a libcall, then precompute all arguments so that we do not
1271 get extraneous instructions emitted as part of the libcall sequence. */
1273 /* If we preallocated the stack space, and some arguments must be passed
1274 on the stack, then we must precompute any parameter which contains a
1275 function call which will store arguments on the stack.
1276 Otherwise, evaluating the parameter may clobber previous parameters
1277 which have already been stored into the stack. (we have code to avoid
1278 such case by saving the outgoing stack arguments, but it results in
1279 worse code) */
1284 {
1291 /* If this is an addressable type, we cannot pre-evaluate it. */
1299 {
1303 #if defined(PROMOTE_FUNCTION_MODE) && !defined(PROMOTE_MODE)
1304 /* CSE will replace this only if it contains args[i].value
1305 pseudo, so convert it down to the declared mode using
1306 a SUBREG. */
1309 {
1315 }
1316 #endif
1317 }
1318 }
1319 }
1321 /* Given the current state of MUST_PREALLOCATE and information about
1322 arguments to a function call in NUM_ACTUALS, ARGS and ARGS_SIZE,
1323 compute and return the final value for MUST_PREALLOCATE. */
1325 static int
1328 {
1329 /* See if we have or want to preallocate stack space.
1331 If we would have to push a partially-in-regs parm
1332 before other stack parms, preallocate stack space instead.
1334 If the size of some parm is not a multiple of the required stack
1335 alignment, we must preallocate.
1337 If the total size of arguments that would otherwise create a copy in
1338 a temporary (such as a CALL) is more than half the total argument list
1339 size, preallocation is faster.
1341 Another reason to preallocate is if we have a machine (like the m88k)
1342 where stack alignment is required to be maintained between every
1343 pair of insns, not just when the call is made. However, we assume here
1344 that such machines either do not have push insns (and hence preallocation
1345 would occur anyway) or the problem is taken care of with
1346 PUSH_ROUNDING. */
1349 {
1355 {
1366 copy_to_evaluate_size
1368 }
1373 }
1375 }
1377 /* If we preallocated stack space, compute the address of each argument
1378 and store it into the ARGS array.
1380 We need not ensure it is a valid memory address here; it will be
1381 validized when it is used.
1383 ARGBLOCK is an rtx for the address of the outgoing arguments. */
1385 static void
1387 {
1389 {
1397 {
1400 rtx addr;
1405 /* Skip this parm if it will not be passed on the stack. */
1413 else
1419 {
1420 /* Only part of the parameter is being passed on the stack.
1421 Generate a simple memory reference of the correct size. */
1427 }
1428 else
1429 {
1433 }
1439 {
1442 }
1447 else
1453 {
1454 /* Only part of the parameter is being passed on the stack.
1455 Generate a simple memory reference of the correct size.
1456 */
1459 }
1460 else
1461 {
1465 }
1468 /* Function incoming arguments may overlap with sibling call
1469 outgoing arguments and we cannot allow reordering of reads
1470 from function arguments with stores to outgoing arguments
1471 of sibling calls. */
1474 }
1475 }
1476 }
1478 /* Given a FNDECL and EXP, return an rtx suitable for use as a target address
1479 in a call instruction.
1481 FNDECL is the tree node for the target function. For an indirect call
1482 FNDECL will be NULL_TREE.
1484 ADDR is the operand 0 of CALL_EXPR for this call. */
1486 static rtx
1488 {
1489 rtx funexp;
1491 /* Get the function to call, in the form of RTL. */
1493 {
1494 /* If this is the first use of the function, see if we need to
1495 make an external definition for it. */
1497 {
1500 }
1502 /* Get a SYMBOL_REF rtx for the function address. */
1504 }
1505 else
1506 /* Generate an rtx (probably a pseudo-register) for the address. */
1507 {
1511 }
1513 }
1515 /* Return true if and only if SIZE storage units (usually bytes)
1516 starting from address ADDR overlap with already clobbered argument
1517 area. This function is used to determine if we should give up a
1518 sibcall. */
1520 static bool
1522 {
1523 HOST_WIDE_INT i;
1531 /* Return true for arg pointer based indexed addressing. */
1536 else
1539 #ifdef ARGS_GROW_DOWNWARD
1541 #endif
1543 {
1550 }
1553 }
1555 /* Do the register loads required for any wholly-register parms or any
1556 parms which are passed both on the stack and in a register. Their
1557 expressions were already evaluated.
1559 Mark all register-parms as living through the call, putting these USE
1560 insns in the CALL_INSN_FUNCTION_USAGE field.
1562 When IS_SIBCALL, perform the check_sibcall_argument_overlap
1563 checking, setting *SIBCALL_FAILURE if appropriate. */
1565 static void
1569 {
1573 {
1577 {
1582 /* Set non-negative if we must move a word at a time, even if
1583 just one word (e.g, partial == 4 && mode == DFmode). Set
1584 to -1 if we just use a normal move insn. This value can be
1585 zero if the argument is a zero size structure. */
1588 ;
1590 {
1593 }
1595 {
1598 }
1599 else
1602 /* Handle calls that pass values in multiple non-contiguous
1603 locations. The Irix 6 ABI has examples of this. */
1608 /* If simple case, just do move. If normal partial, store_one_arg
1609 has already loaded the register for us. In all other cases,
1610 load the register(s) from memory. */
1613 {
1615 #ifdef BLOCK_REG_PADDING
1616 /* Handle case where we have a value that needs shifting
1617 up to the msb. eg. a QImode value and we're padding
1618 upward on a BYTES_BIG_ENDIAN machine. */
1622 {
1623 rtx x;
1626 /* Assigning REG here rather than a temp makes CALL_FUSAGE
1627 report the whole reg as used. Strictly speaking, the
1628 call only uses SIZE bytes at the msb end, but it doesn't
1629 seem worth generating rtl to say that. */
1636 }
1637 #endif
1638 }
1640 /* If we have pre-computed the values to put in the registers in
1641 the case of non-aligned structures, copy them in now. */
1649 {
1652 /* Check for overlap with already clobbered argument area. */
1655 size))
1658 /* Handle a BLKmode that needs shifting. */
1660 #ifdef BLOCK_REG_PADDING
1662 #else
1663 && BYTES_BIG_ENDIAN
1664 #endif
1665 )
1666 {
1680 }
1681 else
1683 }
1685 /* When a parameter is a block, and perhaps in other cases, it is
1686 possible that it did a load from an argument slot that was
1687 already clobbered. */
1692 /* Handle calls that pass values in multiple non-contiguous
1693 locations. The Irix 6 ABI has examples of this. */
1700 }
1701 }
1702 }
1704 /* We need to pop PENDING_STACK_ADJUST bytes. But, if the arguments
1705 wouldn't fill up an even multiple of PREFERRED_UNIT_STACK_BOUNDARY
1706 bytes, then we would need to push some additional bytes to pad the
1707 arguments. So, we compute an adjust to the stack pointer for an
1708 amount that will leave the stack under-aligned by UNADJUSTED_ARGS_SIZE
1709 bytes. Then, when the arguments are pushed the stack will be perfectly
1710 aligned. ARGS_SIZE->CONSTANT is set to the number of bytes that should
1711 be popped after the call. Returns the adjustment. */
1713 static int
1717 {
1718 /* The number of bytes to pop so that the stack will be
1719 under-aligned by UNADJUSTED_ARGS_SIZE bytes. */
1720 HOST_WIDE_INT adjustment;
1721 /* The alignment of the stack after the arguments are pushed, if we
1722 just pushed the arguments without adjust the stack here. */
1725 unadjusted_alignment
1729 /* We want to get rid of as many of the PENDING_STACK_ADJUST bytes
1730 as possible -- leaving just enough left to cancel out the
1731 UNADJUSTED_ALIGNMENT. In other words, we want to ensure that the
1732 PENDING_STACK_ADJUST is non-negative, and congruent to
1733 -UNADJUSTED_ALIGNMENT modulo the PREFERRED_UNIT_STACK_BOUNDARY. */
1735 /* Begin by trying to pop all the bytes. */
1736 unadjusted_alignment
1737 = (unadjusted_alignment
1740 /* Push enough additional bytes that the stack will be aligned
1741 after the arguments are pushed. */
1743 {
1746 else
1748 }
1750 /* Now, sets ARGS_SIZE->CONSTANT so that we pop the right number of
1751 bytes after the call. The right number is the entire
1752 PENDING_STACK_ADJUST less our ADJUSTMENT plus the amount required
1753 by the arguments in the first place. */
1754 args_size->constant
1758 }
1760 /* Scan X expression if it does not dereference any argument slots
1761 we already clobbered by tail call arguments (as noted in stored_args_map
1762 bitmap).
1763 Return nonzero if X expression dereferences such argument slots,
1764 zero otherwise. */
1766 static int
1768 {
1769 RTX_CODE code;
1782 /* Scan all subexpressions. */
1785 {
1787 {
1790 }
1792 {
1796 }
1797 }
1799 }
1801 /* Scan sequence after INSN if it does not dereference any argument slots
1802 we already clobbered by tail call arguments (as noted in stored_args_map
1803 bitmap). If MARK_STORED_ARGS_MAP, add stack slots for ARG to
1804 stored_args_map bitmap afterwards (when ARG is a register MARK_STORED_ARGS_MAP
1805 should be 0). Return nonzero if sequence after INSN dereferences such argument
1806 slots, zero otherwise. */
1808 static int
1810 {
1815 else
1824 {
1825 #ifdef ARGS_GROW_DOWNWARD
1827 #else
1829 #endif
1833 }
1835 }
1837 /* Given that a function returns a value of mode MODE at the most
1838 significant end of hard register VALUE, shift VALUE left or right
1839 as specified by LEFT_P. Return true if some action was needed. */
1841 bool
1843 {
1844 HOST_WIDE_INT shift;
1851 /* Use ashr rather than lshr for right shifts. This is for the benefit
1852 of the MIPS port, which requires SImode values to be sign-extended
1853 when stored in 64-bit registers. */
1858 }
1860 /* Generate all the code for a CALL_EXPR exp
1861 and return an rtx for its value.
1862 Store the value in TARGET (specified as an rtx) if convenient.
1863 If the value is stored in TARGET then TARGET is returned.
1864 If IGNORE is nonzero, then we ignore the value of the function call. */
1866 rtx
1868 {
1869 /* Nonzero if we are currently expanding a call. */
1872 /* RTX for the function to be called. */
1873 rtx funexp;
1874 /* Sequence of insns to perform a normal "call". */
1876 /* Sequence of insns to perform a tail "call". */
1878 /* Data type of the function. */
1879 tree funtype;
1880 tree type_arg_types;
1881 /* Declaration of the function being called,
1882 or 0 if the function is computed (not known by name). */
1884 /* The type of the function being called. */
1885 tree fntype;
1889 /* Register in which non-BLKmode value will be returned,
1890 or 0 if no value or if value is BLKmode. */
1891 rtx valreg;
1892 /* Address where we should return a BLKmode value;
1893 0 if value not BLKmode. */
1895 /* Nonzero if that address is being passed by treating it as
1896 an extra, implicit first parameter. Otherwise,
1897 it is passed by being copied directly into struct_value_rtx. */
1899 /* Holds the value of implicit argument for the struct value. */
1901 /* Size of aggregate value wanted, or zero if none wanted
1902 or if we are using the non-reentrant PCC calling convention
1903 or expecting the value in registers. */
1905 /* Nonzero if called function returns an aggregate in memory PCC style,
1906 by returning the address of where to find it. */
1910 /* Number of actual parameters in this call, including struct value addr. */
1912 /* Number of named args. Args after this are anonymous ones
1913 and they must all go on the stack. */
1915 /* Number of complex actual arguments that need to be split. */
1918 /* Vector of information about each argument.
1919 Arguments are numbered in the order they will be pushed,
1920 not the order they are written. */
1923 /* Total size in bytes of all the stack-parms scanned so far. */
1926 /* Size of arguments before any adjustments (such as rounding). */
1928 /* Data on reg parms scanned so far. */
1929 CUMULATIVE_ARGS args_so_far;
1930 /* Nonzero if a reg parm has been scanned. */
1932 /* Nonzero if this is an indirect function call. */
1934 /* Nonzero if we must avoid push-insns in the args for this call.
1935 If stack space is allocated for register parameters, but not by the
1936 caller, then it is preallocated in the fixed part of the stack frame.
1937 So the entire argument block must then be preallocated (i.e., we
1938 ignore PUSH_ROUNDING in that case). */
1942 /* Size of the stack reserved for parameter registers. */
1945 /* Address of space preallocated for stack parms
1946 (on machines that lack push insns), or 0 if space not preallocated. */
1949 /* Mask of ECF_ flags. */
1951 #ifdef REG_PARM_STACK_SPACE
1952 /* Define the boundary of the register parm stack space that needs to be
1953 saved, if any. */
1956 #endif
1964 /* State variables to track stack modifications. */
1970 /* Some stack pointer alterations we make are performed via
1971 allocate_dynamic_stack_space. This modifies the stack_pointer_delta,
1972 which we then also need to save/restore along the way. */
1975 rtx call_fusage;
1979 /* The alignment of the stack, in bits. */
1981 /* The alignment of the stack, in bytes. */
1983 /* The static chain value to use for this call. */
1984 rtx static_chain_value;
1985 /* See if this is "nothrow" function call. */
1989 /* See if we can find a DECL-node for the actual function, and get the
1990 function attributes (flags) from the function decl or type node. */
1993 {
1996 }
1997 else
1998 {
2001 }
2005 /* Warn if this value is an aggregate type,
2006 regardless of which calling convention we are using for it. */
2010 /* If the result of a pure or const function call is ignored (or void),
2011 and none of its arguments are volatile, we can avoid expanding the
2012 call and just evaluate the arguments for side-effects. */
2016 {
2018 tree arg;
2019 call_expr_arg_iterator iter;
2023 {
2026 }
2029 {
2033 }
2034 }
2036 #ifdef REG_PARM_STACK_SPACE
2038 #endif
2043 /* Set up a place to return a structure. */
2045 /* Cater to broken compilers. */
2047 {
2048 /* This call returns a big structure. */
2051 #ifdef PCC_STATIC_STRUCT_RETURN
2052 {
2054 }
2056 {
2061 else
2062 {
2063 /* For variable-sized objects, we must be called with a target
2064 specified. If we were to allocate space on the stack here,
2065 we would have no way of knowing when to free it. */
2071 }
2072 }
2074 }
2076 /* Figure out the amount to which the stack should be aligned. */
2079 {
2083 }
2085 /* Operand 0 is a pointer-to-function; get the type of the function. */
2090 /* Count whether there are actual complex arguments that need to be split
2091 into their real and imaginary parts. Munge the type_arg_types
2092 appropriately here as well. */
2094 {
2095 call_expr_arg_iterator iter;
2096 tree arg;
2098 {
2102 num_complex_actuals++;
2103 }
2105 }
2106 else
2112 /* If struct_value_rtx is 0, it means pass the address
2113 as if it were an extra parameter. Put the argument expression
2114 in structure_value_addr_value. */
2116 {
2117 /* If structure_value_addr is a REG other than
2118 virtual_outgoing_args_rtx, we can use always use it. If it
2119 is not a REG, we must always copy it into a register.
2120 If it is virtual_outgoing_args_rtx, we must copy it to another
2121 register in some cases. */
2123 || (ACCUMULATE_OUTGOING_ARGS
2124 && stack_arg_under_construction
2130 structure_value_addr_value =
2133 }
2135 /* Count the arguments and set NUM_ACTUALS. */
2136 num_actuals =
2139 /* Compute number of named args.
2140 First, do a raw count of the args for INIT_CUMULATIVE_ARGS. */
2143 n_named_args
2145 /* Count the struct value address, if it is passed as a parm. */
2147 else
2148 /* If we know nothing, treat all args as named. */
2151 /* Start updating where the next arg would go.
2153 On some machines (such as the PA) indirect calls have a different
2154 calling convention than normal calls. The fourth argument in
2155 INIT_CUMULATIVE_ARGS tells the backend if this is an indirect call
2156 or not. */
2159 /* Now possibly adjust the number of named args.
2160 Normally, don't include the last named arg if anonymous args follow.
2161 We do include the last named arg if
2162 targetm.calls.strict_argument_naming() returns nonzero.
2163 (If no anonymous args follow, the result of list_length is actually
2164 one too large. This is harmless.)
2166 If targetm.calls.pretend_outgoing_varargs_named() returns
2167 nonzero, and targetm.calls.strict_argument_naming() returns zero,
2168 this machine will be able to place unnamed args that were passed
2169 in registers into the stack. So treat all args as named. This
2170 allows the insns emitting for a specific argument list to be
2171 independent of the function declaration.
2173 If targetm.calls.pretend_outgoing_varargs_named() returns zero,
2174 we do not have any reliable way to pass unnamed args in
2175 registers, so we must force them into memory. */
2179 ;
2182 /* Don't include the last named arg. */
2184 else
2185 /* Treat all args as named. */
2188 /* Make a vector to hold all the information about each arg. */
2192 /* Build up entries in the ARGS array, compute the size of the
2193 arguments into ARGS_SIZE, etc. */
2203 {
2204 /* If this function requires a variable-sized argument list, don't
2205 try to make a cse'able block for this call. We may be able to
2206 do this eventually, but it is too complicated to keep track of
2207 what insns go in the cse'able block and which don't. */
2211 }
2213 /* Now make final decision about preallocating stack space. */
2218 /* If the structure value address will reference the stack pointer, we
2219 must stabilize it. We don't need to do this if we know that we are
2220 not going to adjust the stack pointer in processing this call. */
2225 structure_value_addr))
2230 /* Tail calls can make things harder to debug, and we've traditionally
2231 pushed these optimizations into -O2. Don't try if we're already
2232 expanding a call, as that means we're an argument. Don't try if
2233 there's cleanups, as we know there's code to follow the call. */
2236 || !flag_optimize_sibling_calls
2242 /* Rest of purposes for tail call optimizations to fail. */
2244 #ifdef HAVE_sibcall_epilogue
2245 !HAVE_sibcall_epilogue
2246 #else
2247 1
2248 #endif
2249 || !try_tail_call
2250 /* Doing sibling call optimization needs some work, since
2251 structure_value_addr can be allocated on the stack.
2252 It does not seem worth the effort since few optimizable
2253 sibling calls will return a structure. */
2255 /* Check whether the target is able to optimize the call
2256 into a sibcall. */
2258 /* Functions that do not return exactly once may not be sibcall
2259 optimized. */
2262 /* If the called function is nested in the current one, it might access
2263 some of the caller's arguments, but could clobber them beforehand if
2264 the argument areas are shared. */
2266 /* If this function requires more stack slots than the current
2267 function, we cannot change it into a sibling call.
2268 current_function_pretend_args_size is not part of the
2269 stack allocated by our caller. */
2272 /* If the callee pops its own arguments, then it must pop exactly
2273 the same number of arguments as the current function. */
2277 current_function_args_size))
2281 /* Ensure current function's preferred stack boundary is at least
2282 what we need. We don't have to increase alignment for recursive
2283 functions. */
2292 /* We want to make two insn chains; one for a sibling call, the other
2293 for a normal call. We will select one of the two chains after
2294 initial RTL generation is complete. */
2296 {
2298 /* We want to emit any pending stack adjustments before the tail
2299 recursion "call". That way we know any adjustment after the tail
2300 recursion call can be ignored if we indeed use the tail
2301 call expansion. */
2304 rtx insns;
2308 {
2309 /* State variables we need to save and restore between
2310 iterations. */
2313 }
2316 else
2319 /* Other state variables that we must reinitialize each time
2320 through the loop (that are not initialized by the loop itself). */
2324 /* Start a new sequence for the normal call case.
2326 From this point on, if the sibling call fails, we want to set
2327 sibcall_failure instead of continuing the loop. */
2330 /* Don't let pending stack adjusts add up to too much.
2331 Also, do all pending adjustments now if there is any chance
2332 this might be a call to alloca or if we are expanding a sibling
2333 call sequence or if we are calling a function that is to return
2334 with stack pointer depressed.
2335 Also do the adjustments before a throwing call, otherwise
2336 exception handling can fail; PR 19225. */
2345 /* When calling a const function, we must pop the stack args right away,
2346 so that the pop is deleted or moved with the call. */
2348 NO_DEFER_POP;
2350 /* Precompute any arguments as needed. */
2354 /* Now we are about to start emitting insns that can be deleted
2355 if a libcall is deleted. */
2363 /* Compute the actual size of the argument block required. The variable
2364 and constant sizes must be combined, the size may have to be rounded,
2365 and there may be a minimum required size. When generating a sibcall
2366 pattern, do not round up, since we'll be re-using whatever space our
2367 caller provided. */
2368 unadjusted_args_size
2376 /* The argument block when performing a sibling call is the
2377 incoming argument block. */
2379 {
2381 argblock
2382 #ifdef STACK_GROWS_DOWNWARD
2384 #else
2386 #endif
2389 }
2391 /* If we have no actual push instructions, or shouldn't use them,
2392 make space for all args right now. */
2394 {
2396 {
2401 /* stack_arg_under_construction says whether a stack arg is
2402 being constructed at the old stack level. Pushing the stack
2403 gets a clean outgoing argument block. */
2406 }
2408 }
2409 else
2410 {
2411 /* Note that we must go through the motions of allocating an argument
2412 block even if the size is zero because we may be storing args
2413 in the area reserved for register arguments, which may be part of
2414 the stack frame. */
2418 /* Store the maximum argument space used. It will be pushed by
2419 the prologue (if ACCUMULATE_OUTGOING_ARGS, or stack overflow
2420 checking). */
2426 {
2428 {
2429 /* Since the stack pointer will never be pushed, it is
2430 possible for the evaluation of a parm to clobber
2431 something we have already written to the stack.
2432 Since most function calls on RISC machines do not use
2433 the stack, this is uncommon, but must work correctly.
2435 Therefore, we save any area of the stack that was already
2436 written and that we are using. Here we set up to do this
2437 by making a new stack usage map from the old one. The
2438 actual save will be done by store_one_arg.
2440 Another approach might be to try to reorder the argument
2441 evaluations to avoid this conflicting stack usage. */
2443 /* Since we will be writing into the entire argument area,
2444 the map must be allocated for its entire size, not just
2445 the part that is the responsibility of the caller. */
2449 #ifdef ARGS_GROW_DOWNWARD
2452 #else
2454 needed);
2455 #endif
2463 initial_highest_arg_in_use);
2467 (highest_outgoing_arg_in_use
2471 /* The address of the outgoing argument list must not be
2472 copied to a register here, because argblock would be left
2473 pointing to the wrong place after the call to
2474 allocate_dynamic_stack_space below. */
2477 }
2478 else
2479 {
2481 {
2482 /* Try to reuse some or all of the pending_stack_adjust
2483 to get this space. */
2484 needed
2485 = (combine_pending_stack_adjustment_and_call
2488 preferred_unit_stack_boundary));
2490 /* combine_pending_stack_adjustment_and_call computes
2491 an adjustment before the arguments are allocated.
2492 Account for them and see whether or not the stack
2493 needs to go up or down. */
2497 {
2498 /* We're releasing stack space. */
2499 /* ??? We can avoid any adjustment at all if we're
2500 already aligned. FIXME. */
2504 }
2505 else
2506 /* We need to allocate space. We'll do that in
2507 push_block below. */
2509 }
2511 /* Special case this because overhead of `push_block' in
2512 this case is non-trivial. */
2515 else
2516 {
2518 #ifdef ARGS_GROW_DOWNWARD
2520 #endif
2521 }
2523 /* We only really need to call `copy_to_reg' in the case
2524 where push insns are going to be used to pass ARGBLOCK
2525 to a function call in ARGS. In that case, the stack
2526 pointer changes value from the allocation point to the
2527 call point, and hence the value of
2528 VIRTUAL_OUTGOING_ARGS_RTX changes as well. But might
2529 as well always do it. */
2531 }
2532 }
2533 }
2536 {
2537 /* The save/restore code in store_one_arg handles all
2538 cases except one: a constructor call (including a C
2539 function returning a BLKmode struct) to initialize
2540 an argument. */
2542 {
2543 rtx push_size
2548 {
2550 NULL_RTX);
2554 /* stack_arg_under_construction says whether a stack
2555 arg is being constructed at the old stack level.
2556 Pushing the stack gets a clean outgoing argument
2557 block. */
2558 old_stack_arg_under_construction
2561 /* Make a new map for the new argument list. */
2567 }
2569 BITS_PER_UNIT);
2570 }
2572 /* If argument evaluation might modify the stack pointer,
2573 copy the address of the argument list to a register. */
2576 {
2579 }
2580 }
2584 /* If we push args individually in reverse order, perform stack alignment
2585 before the first push (the last arg). */
2588 {
2589 /* When the stack adjustment is pending, we get better code
2590 by combining the adjustments. */
2594 {
2595 pending_stack_adjust
2596 = (combine_pending_stack_adjustment_and_call
2599 preferred_unit_stack_boundary));
2601 }
2605 }
2606 /* Now that the stack is properly aligned, pops can't safely
2607 be deferred during the evaluation of the arguments. */
2608 NO_DEFER_POP;
2612 /* Figure out the register where the value, if any, will come back. */
2616 {
2620 else
2624 /* If VALREG is a PARALLEL whose first member has a zero
2625 offset, use that. This is for targets such as m68k that
2626 return the same value in multiple places. */
2628 {
2635 }
2636 }
2638 /* Precompute all register parameters. It isn't safe to compute anything
2639 once we have started filling any specific hard regs. */
2644 else
2647 #ifdef REG_PARM_STACK_SPACE
2648 /* Save the fixed argument area if it's part of the caller's frame and
2649 is clobbered by argument setup for this call. */
2653 #endif
2655 /* Now store (and compute if necessary) all non-register parms.
2656 These come before register parms, since they can require block-moves,
2657 which could clobber the registers used for register parms.
2658 Parms which have partial registers are not stored here,
2659 but we do preallocate space here if they want that. */
2663 {
2668 reg_parm_stack_space)
2680 call_fusage);
2681 }
2683 /* If we have a parm that is passed in registers but not in memory
2684 and whose alignment does not permit a direct copy into registers,
2685 make a group of pseudos that correspond to each register that we
2686 will later fill. */
2690 /* Now store any partially-in-registers parm.
2691 This is the last place a block-move can happen. */
2695 {
2700 reg_parm_stack_space)
2705 }
2707 /* If we pushed args in forward order, perform stack alignment
2708 after pushing the last arg. */
2713 /* If register arguments require space on the stack and stack space
2714 was not preallocated, allocate stack space here for arguments
2715 passed in registers. */
2720 /* Pass the function the address in which to return a
2721 structure value. */
2723 {
2724 structure_value_addr
2729 NULL_RTX)));
2733 }
2741 /* Save a pointer to the last insn before the call, so that we can
2742 later safely search backwards to find the CALL_INSN. */
2745 /* Set up next argument register. For sibling calls on machines
2746 with register windows this should be the incoming register. */
2747 #ifdef FUNCTION_INCOMING_ARG
2751 else
2752 #endif
2756 /* All arguments and registers used for the call must be set up by
2757 now! */
2759 /* Stack must be properly aligned now. */
2763 /* Generate the actual call instruction. */
2769 /* If a non-BLKmode value is returned at the most significant end
2770 of a register, shift the register right by the appropriate amount
2771 and update VALREG accordingly. BLKmode values are handled by the
2772 group load/store machinery below. */
2774 && !pcc_struct_value
2777 {
2781 }
2783 /* If call is cse'able, make appropriate pair of reg-notes around it.
2784 Test valreg so we don't crash; may safely ignore `const'
2785 if return type is void. Disable for PARALLEL return values, because
2786 we have no way to move such values into a pseudo register. */
2788 {
2789 rtx insns;
2790 rtx insn;
2795 /* Expansion of block moves possibly introduced a loop that may
2796 not appear inside libcall block. */
2802 {
2805 }
2806 else
2807 {
2811 /* Mark the return value as a pointer if needed. */
2818 && fndecl
2826 else
2827 {
2828 /* Construct an "equal form" for the value which
2829 mentions all the arguments in order as well as
2830 the function name. */
2841 note);
2842 }
2846 }
2847 }
2849 {
2853 /* The return value from a malloc-like function is a pointer. */
2859 /* The return value from a malloc-like function can not alias
2860 anything else. */
2865 /* Write out the sequence. */
2870 }
2872 /* For calls to `setjmp', etc., inform
2873 function.c:setjmp_warnings that it should complain if
2874 nonvolatile values are live. For functions that cannot
2875 return, inform flow that control does not fall through. */
2878 {
2879 /* The barrier must be emitted
2880 immediately after the CALL_INSN. Some ports emit more
2881 than just a CALL_INSN above, so we must search for it here. */
2885 {
2887 /* There was no CALL_INSN? */
2889 }
2893 /* Stack adjustments after a noreturn call are dead code.
2894 However when NO_DEFER_POP is in effect, we must preserve
2895 stack_pointer_delta. */
2897 {
2900 }
2901 }
2903 /* If value type not void, return an rtx for the value. */
2909 {
2911 {
2912 target
2915 structure_value_addr));
2917 }
2918 }
2920 {
2921 /* This is the special C++ case where we need to
2922 know what the true target was. We take care to
2923 never use this value more than once in one expression. */
2927 }
2928 /* Handle calls that return values in multiple non-contiguous locations.
2929 The Irix 6 ABI has examples of this. */
2931 {
2933 {
2934 /* This will only be assigned once, so it can be readonly. */
2940 }
2946 /* We can not support sibling calls for this case. */
2948 }
2952 {
2955 /* We have to copy a return value in a CLASS_LIKELY_SPILLED hard
2956 reg to a plain register. */
2963 /* If TARGET is a MEM in the argument area, and we have
2964 saved part of the argument area, then we can't store
2965 directly into TARGET as it may get overwritten when we
2966 restore the argument save area below. Don't work too
2967 hard though and simply force TARGET to a register if it
2968 is a MEM; the optimizer is quite likely to sort it out. */
2972 {
2975 }
2979 else
2980 {
2981 /* TARGET and VALREG cannot be equal at this point
2982 because the latter would not have
2983 REG_FUNCTION_VALUE_P true, while the former would if
2984 it were referring to the same register.
2986 If they refer to the same register, this move will be
2987 a no-op, except when function inlining is being
2988 done. */
2991 /* If we are setting a MEM, this code must be executed.
2992 Since it is emitted after the call insn, sibcall
2993 optimization cannot be performed in that case. */
2996 }
2997 }
2999 {
3002 /* We can not support sibling calls for this case. */
3004 }
3005 else
3009 {
3010 /* If we promoted this return value, make the proper SUBREG.
3011 TARGET might be const0_rtx here, so be careful. */
3015 {
3022 /* If we don't promote as expected, something is wrong. */
3028 {
3035 }
3039 }
3040 }
3042 /* If size of args is variable or this was a constructor call for a stack
3043 argument, restore saved stack-pointer value. */
3046 {
3055 }
3057 {
3058 #ifdef REG_PARM_STACK_SPACE
3062 #endif
3064 /* If we saved any argument areas, restore them. */
3067 {
3069 rtx stack_area
3076 else
3079 BLOCK_OP_CALL_PARM);
3080 }
3084 }
3086 /* If this was alloca, record the new stack level for nonlocal gotos.
3087 Check for the handler slots since we might not have a save area
3088 for non-local gotos. */
3093 /* Free up storage we no longer need. */
3102 {
3105 /* Restore the pending stack adjustment now that we have
3106 finished generating the sibling call sequence. */
3111 /* Prepare arg structure for next iteration. */
3113 {
3117 }
3120 }
3121 else
3122 {
3125 /* Verify that we've deallocated all the stack we used. */
3127 || (old_stack_allocated
3129 }
3131 /* If something prevents making this a sibling call,
3132 zero out the sequence. */
3135 else
3137 }
3139 /* If tail call production succeeded, we need to remove REG_EQUIV notes on
3140 arguments too, as argument area is now clobbered by the call. */
3142 {
3145 }
3146 else
3149 currently_expanding_call--;
3151 /* If this function returns with the stack pointer depressed, ensure
3152 this block saves and restores the stack pointer, show it was
3153 changed, and adjust for any outgoing arg space. */
3155 {
3159 }
3165 }
3167 /* A sibling call sequence invalidates any REG_EQUIV notes made for
3168 this function's incoming arguments.
3170 At the start of RTL generation we know the only REG_EQUIV notes
3171 in the rtl chain are those for incoming arguments, so we can look
3172 for REG_EQUIV notes between the start of the function and the
3173 NOTE_INSN_FUNCTION_BEG.
3175 This is (slight) overkill. We could keep track of the highest
3176 argument we clobber and be more selective in removing notes, but it
3177 does not seem to be worth the effort. */
3179 void
3181 {
3182 rtx insn;
3185 {
3186 rtx note;
3188 /* There are never REG_EQUIV notes for the incoming arguments
3189 after the NOTE_INSN_FUNCTION_BEG note, so stop if we see it. */
3199 }
3200 }
3202 /* Traverse a list of TYPES and expand all complex types into their
3203 components. */
3204 static tree
3206 {
3207 tree p;
3209 /* Before allocating memory, check for the common case of no complex. */
3211 {
3216 }
3219 found:
3223 {
3228 {
3231 /* Rewrite complex type with component type. */
3235 /* Add another component type for the imaginary part. */
3240 /* Skip the newly created node. */
3242 }
3243 }
3246 }
3247 \f
3248 /* Output a library call to function FUN (a SYMBOL_REF rtx).
3249 The RETVAL parameter specifies whether return value needs to be saved, other
3250 parameters are documented in the emit_library_call function below. */
3252 static rtx
3256 {
3257 /* Total size in bytes of all the stack-parms scanned so far. */
3259 /* Size of arguments before any adjustments (such as rounding). */
3262 rtx fun;
3266 CUMULATIVE_ARGS args_so_far;
3267 struct arg
3268 {
3269 rtx value;
3271 rtx reg;
3274 rtx save_area;
3275 };
3280 rtx valreg;
3286 rtx before_call;
3289 #ifdef REG_PARM_STACK_SPACE
3290 /* Define the boundary of the register parm stack space that needs to be
3291 save, if any. */
3294 #endif
3296 /* Size of the stack reserved for parameter registers. */
3303 #ifdef REG_PARM_STACK_SPACE
3305 #endif
3307 /* By default, library functions can not throw. */
3311 {
3335 }
3338 /* Ensure current function's preferred stack boundary is at least
3339 what we need. */
3343 /* If this kind of value comes back in memory,
3344 decide where in memory it should come back. */
3346 {
3349 {
3350 #ifdef PCC_STATIC_STRUCT_RETURN
3351 rtx pointer_reg
3361 else
3363 #endif
3364 /* This call returns a big structure. */
3366 }
3367 }
3368 else
3371 /* ??? Unfinished: must pass the memory address as an argument. */
3373 /* Copy all the libcall-arguments out of the varargs data
3374 and into a vector ARGVEC.
3376 Compute how to pass each argument. We only support a very small subset
3377 of the full argument passing conventions to limit complexity here since
3378 library functions shouldn't have many args. */
3383 #ifdef INIT_CUMULATIVE_LIBCALL_ARGS
3385 #else
3387 #endif
3394 /* Now we are about to start emitting insns that can be deleted
3395 if a libcall is deleted. */
3401 /* If there's a structure value address to be passed,
3402 either pass it in the special place, or pass it as an extra argument. */
3404 {
3407 nargs++;
3409 /* Make sure it is a reasonable operand for a move or push insn. */
3423 #ifdef STACK_PARMS_IN_REG_PARM_AREA
3425 #else
3427 #endif
3436 count++;
3437 }
3440 {
3444 /* We cannot convert the arg value to the mode the library wants here;
3445 must do it earlier where we know the signedness of the arg. */
3449 /* Make sure it is a reasonable operand for a move or push insn. */
3455 {
3456 rtx slot;
3457 int must_copy
3460 /* loop.c won't look at CALL_INSN_FUNCTION_USAGE of const/pure
3461 functions, so we have to pretend this isn't such a function. */
3463 {
3467 }
3470 /* If this was a CONST function, it is now PURE since
3471 it now reads memory. */
3473 {
3476 }
3480 else
3481 {
3485 }
3489 call_fusage);
3493 slot),
3494 call_fusage);
3498 }
3509 #ifdef STACK_PARMS_IN_REG_PARM_AREA
3511 #else
3513 #endif
3524 }
3526 /* If this machine requires an external definition for library
3527 functions, write one out. */
3532 + stack_pointer_delta
3534 / STACK_BYTES
3539 reg_parm_stack_space);
3548 {
3549 /* Since the stack pointer will never be pushed, it is possible for
3550 the evaluation of a parm to clobber something we have already
3551 written to the stack. Since most function calls on RISC machines
3552 do not use the stack, this is uncommon, but must work correctly.
3554 Therefore, we save any area of the stack that was already written
3555 and that we are using. Here we set up to do this by making a new
3556 stack usage map from the old one.
3558 Another approach might be to try to reorder the argument
3559 evaluations to avoid this conflicting stack usage. */
3563 /* Since we will be writing into the entire argument area, the
3564 map must be allocated for its entire size, not just the part that
3565 is the responsibility of the caller. */
3569 #ifdef ARGS_GROW_DOWNWARD
3572 #else
3574 needed);
3575 #endif
3581 initial_highest_arg_in_use);
3588 /* We must be careful to use virtual regs before they're instantiated,
3589 and real regs afterwards. Loop optimization, for example, can create
3590 new libcalls after we've instantiated the virtual regs, and if we
3591 use virtuals anyway, they won't match the rtl patterns. */
3595 else
3597 }
3598 else
3599 {
3602 }
3604 /* If we push args individually in reverse order, perform stack alignment
3605 before the first push (the last arg). */
3611 {
3614 }
3615 else
3616 {
3619 }
3621 #ifdef REG_PARM_STACK_SPACE
3623 {
3624 /* The argument list is the property of the called routine and it
3625 may clobber it. If the fixed area has been used for previous
3626 parameters, we must save and restore it. */
3629 }
3630 #endif
3632 /* Push the args that need to be pushed. */
3634 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
3635 are to be pushed. */
3637 {
3645 {
3647 {
3648 /* If this is being stored into a pre-allocated, fixed-size,
3649 stack area, save any previous data at that location. */
3651 #ifdef ARGS_GROW_DOWNWARD
3652 /* stack_slot is negative, but we want to index stack_usage_map
3653 with positive values. */
3656 #else
3659 #endif
3662 /* Don't worry about things in the fixed argument area;
3663 it has already been saved. */
3667 i++;
3670 {
3671 /* We need to make a save area. */
3672 unsigned int size
3674 enum machine_mode save_mode
3676 rtx adr
3679 rtx stack_area
3683 {
3690 stack_area,
3692 BLOCK_OP_CALL_PARM);
3693 }
3694 else
3695 {
3699 }
3700 }
3701 }
3706 reg_parm_stack_space,
3709 /* Now mark the segment we just used. */
3714 NO_DEFER_POP;
3717 {
3718 rtx use;
3720 /* Indicate argument access so that alias.c knows that these
3721 values are live. */
3725 else
3726 /* When arguments are pushed, trying to tell alias.c where
3727 exactly this argument is won't work, because the
3728 auto-increment causes confusion. So we merely indicate
3729 that we access something with a known mode somewhere on
3730 the stack. */
3736 }
3737 }
3738 }
3740 /* If we pushed args in forward order, perform stack alignment
3741 after pushing the last arg. */
3748 else
3753 /* Now load any reg parms into their regs. */
3755 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
3756 are to be pushed. */
3758 {
3764 /* Handle calls that pass values in multiple non-contiguous
3765 locations. The PA64 has examples of this for library calls. */
3771 NO_DEFER_POP;
3772 }
3774 /* Any regs containing parms remain in use through the call. */
3776 {
3781 {
3784 {
3789 }
3790 else
3792 }
3793 }
3795 /* Pass the function the address in which to return a structure value. */
3797 {
3801 NULL_RTX)));
3804 }
3806 /* Don't allow popping to be deferred, since then
3807 cse'ing of library calls could delete a call and leave the pop. */
3808 NO_DEFER_POP;
3812 /* Stack must be properly aligned now. */
3818 /* We pass the old value of inhibit_defer_pop + 1 to emit_call_1, which
3819 will set inhibit_defer_pop to that value. */
3820 /* The return type is needed to decide how many bytes the function pops.
3821 Signedness plays no role in that, so for simplicity, we pretend it's
3822 always signed. We also assume that the list of arguments passed has
3823 no impact, so we pretend it is unknown. */
3829 struct_value_size,
3831 valreg,
3834 /* For calls to `setjmp', etc., inform function.c:setjmp_warnings
3835 that it should complain if nonvolatile values are live. For
3836 functions that cannot return, inform flow that control does not
3837 fall through. */
3840 {
3841 /* The barrier note must be emitted
3842 immediately after the CALL_INSN. Some ports emit more than
3843 just a CALL_INSN above, so we must search for it here. */
3847 {
3849 /* There was no CALL_INSN? */
3851 }
3854 }
3856 /* Now restore inhibit_defer_pop to its actual original value. */
3857 OK_DEFER_POP;
3859 /* If call is cse'able, make appropriate pair of reg-notes around it.
3860 Test valreg so we don't crash; may safely ignore `const'
3861 if return type is void. Disable for PARALLEL return values, because
3862 we have no way to move such values into a pseudo register. */
3864 {
3865 rtx insns;
3868 {
3872 }
3873 else
3874 {
3876 rtx temp;
3880 {
3885 }
3889 /* Construct an "equal form" for the value which mentions all the
3890 arguments in order as well as the function name. */
3903 note);
3908 }
3909 }
3912 /* Copy the value to the right place. */
3914 {
3916 {
3921 }
3923 {
3927 }
3928 else
3929 {
3930 /* Convert to the proper mode if PROMOTE_MODE has been active. */
3932 {
3940 }
3944 else
3946 }
3947 }
3950 {
3951 #ifdef REG_PARM_STACK_SPACE
3955 #endif
3957 /* If we saved any argument areas, restore them. */
3960 {
3971 BLOCK_OP_CALL_PARM);
3972 else
3974 }
3978 }
3985 }
3986 \f
3987 /* Output a library call to function FUN (a SYMBOL_REF rtx)
3988 (emitting the queue unless NO_QUEUE is nonzero),
3989 for a value of mode OUTMODE,
3990 with NARGS different arguments, passed as alternating rtx values
3991 and machine_modes to convert them to.
3993 FN_TYPE should be LCT_NORMAL for `normal' calls, LCT_CONST for `const'
3994 calls, LCT_PURE for `pure' calls, LCT_CONST_MAKE_BLOCK for `const' calls
3995 which should be enclosed in REG_LIBCALL/REG_RETVAL notes,
3996 LCT_PURE_MAKE_BLOCK for `purep' calls which should be enclosed in
3997 REG_LIBCALL/REG_RETVAL notes with extra (use (memory (scratch)),
3998 or other LCT_ value for other types of library calls. */
4000 void
4003 {
4009 }
4010 \f
4011 /* Like emit_library_call except that an extra argument, VALUE,
4012 comes second and says where to store the result.
4013 (If VALUE is zero, this function chooses a convenient way
4014 to return the value.
4016 This function returns an rtx for where the value is to be found.
4017 If VALUE is nonzero, VALUE is returned. */
4019 rtx
4023 {
4024 rtx result;
4033 }
4034 \f
4035 /* Store a single argument for a function call
4036 into the register or memory area where it must be passed.
4037 *ARG describes the argument value and where to pass it.
4039 ARGBLOCK is the address of the stack-block for all the arguments,
4040 or 0 on a machine where arguments are pushed individually.
4042 MAY_BE_ALLOCA nonzero says this could be a call to `alloca'
4043 so must be careful about how the stack is used.
4045 VARIABLE_SIZE nonzero says that this was a variable-sized outgoing
4046 argument stack. This is used if ACCUMULATE_OUTGOING_ARGS to indicate
4047 that we need not worry about saving and restoring the stack.
4049 FNDECL is the declaration of the function we are calling.
4051 Return nonzero if this arg should cause sibcall failure,
4052 zero otherwise. */
4054 static int
4057 {
4068 /* Push a new temporary level for any temporaries we make for
4069 this argument. */
4073 {
4074 /* If this is being stored into a pre-allocated, fixed-size, stack area,
4075 save any previous data at that location. */
4077 {
4078 #ifdef ARGS_GROW_DOWNWARD
4079 /* stack_slot is negative, but we want to index stack_usage_map
4080 with positive values. */
4083 else
4087 #else
4090 else
4094 #endif
4097 /* Don't worry about things in the fixed argument area;
4098 it has already been saved. */
4102 i++;
4105 {
4106 /* We need to make a save area. */
4113 {
4122 BLOCK_OP_CALL_PARM);
4123 }
4124 else
4125 {
4128 }
4129 }
4130 }
4131 }
4133 /* If this isn't going to be placed on both the stack and in registers,
4134 set up the register and number of words. */
4136 {
4139 else
4142 }
4144 /* Being passed entirely in a register. We shouldn't be called in
4145 this case. */
4148 /* If this arg needs special alignment, don't load the registers
4149 here. */
4153 /* If this is being passed partially in a register, we can't evaluate
4154 it directly into its stack slot. Otherwise, we can. */
4156 {
4157 /* stack_arg_under_construction is nonzero if a function argument is
4158 being evaluated directly into the outgoing argument list and
4159 expand_call must take special action to preserve the argument list
4160 if it is called recursively.
4162 For scalar function arguments stack_usage_map is sufficient to
4163 determine which stack slots must be saved and restored. Scalar
4164 arguments in general have pass_on_stack == 0.
4166 If this argument is initialized by a function which takes the
4167 address of the argument (a C++ constructor or a C function
4168 returning a BLKmode structure), then stack_usage_map is
4169 insufficient and expand_call must push the stack around the
4170 function call. Such arguments have pass_on_stack == 1.
4172 Note that it is always safe to set stack_arg_under_construction,
4173 but this generates suboptimal code if set when not needed. */
4176 stack_arg_under_construction++;
4179 (partial
4184 /* If we are promoting object (or for any other reason) the mode
4185 doesn't agree, convert the mode. */
4192 stack_arg_under_construction--;
4193 }
4195 /* Check for overlap with already clobbered argument area. */
4202 /* Don't allow anything left on stack from computation
4203 of argument to alloca. */
4208 /* If the value is already in the stack slot, we are done. */
4209 ;
4211 {
4215 /* Argument is a scalar, not entirely passed in registers.
4216 (If part is passed in registers, arg->partial says how much
4217 and emit_push_insn will take care of putting it there.)
4219 Push it, and if its size is less than the
4220 amount of space allocated to it,
4221 also bump stack pointer by the additional space.
4222 Note that in C the default argument promotions
4223 will prevent such mismatches. */
4226 /* Compute how much space the push instruction will push.
4227 On many machines, pushing a byte will advance the stack
4228 pointer by a halfword. */
4229 #ifdef PUSH_ROUNDING
4231 #endif
4234 /* Compute how much space the argument should get:
4235 round up to a multiple of the alignment for arguments. */
4241 /* Compute the alignment of the pushed argument. */
4244 {
4247 {
4250 }
4251 }
4253 /* This isn't already where we want it on the stack, so put it there.
4254 This can either be done with push or copy insns. */
4260 /* Unless this is a partially-in-register argument, the argument is now
4261 in the stack. */
4264 }
4265 else
4266 {
4267 /* BLKmode, at least partly to be pushed. */
4271 rtx size_rtx;
4273 /* Pushing a nonscalar.
4274 If part is passed in registers, PARTIAL says how much
4275 and emit_push_insn will take care of putting it there. */
4277 /* Round its size up to a multiple
4278 of the allocation unit for arguments. */
4281 {
4284 }
4285 else
4286 {
4287 /* PUSH_ROUNDING has no effect on us, because emit_push_insn
4288 for BLKmode is careful to avoid it. */
4294 }
4298 /* When an argument is padded down, the block is aligned to
4299 PARM_BOUNDARY, but the actual argument isn't. */
4301 {
4305 {
4308 }
4309 }
4312 {
4313 /* emit_push_insn might not work properly if arg->value and
4314 argblock + arg->locate.offset areas overlap. */
4321 current_function_internal_arg_pointer
4323 {
4327 /* expand_call should ensure this. */
4332 {
4335 }
4337 {
4340 }
4341 }
4342 }
4349 /* Unless this is a partially-in-register argument, the argument is now
4350 in the stack.
4352 ??? Unlike the case above, in which we want the actual
4353 address of the data, so that we can load it directly into a
4354 register, here we want the address of the stack slot, so that
4355 it's properly aligned for word-by-word copying or something
4356 like that. It's not clear that this is always correct. */
4359 }
4362 {
4364 arg->parallel_value
4367 }
4369 /* Mark all slots this store used. */
4375 /* Once we have pushed something, pops can't safely
4376 be deferred during the rest of the arguments. */
4377 NO_DEFER_POP;
4379 /* Free any temporary slots made in processing this argument. Show
4380 that we might have taken the address of something and pushed that
4381 as an operand. */
4387 }
4389 /* Nonzero if we do not know how to pass TYPE solely in registers. */
4391 bool
4393 tree type)
4394 {
4398 /* If the type has variable size... */
4402 /* If the type is marked as addressable (it is required
4403 to be constructed into the stack)... */
4408 }
4410 /* Another version of the TARGET_MUST_PASS_IN_STACK hook. This one
4411 takes trailing padding of a structure into account. */
4412 /* ??? Should be able to merge these two by examining BLOCK_REG_PADDING. */
4414 bool
4416 {
4420 /* If the type has variable size... */
4424 /* If the type is marked as addressable (it is required
4425 to be constructed into the stack)... */
4429 /* If the padding and mode of the type is such that a copy into
4430 a register would put it into the wrong part of the register. */
4438 }