| blob | cfcf01cf4673b70831a693171b07c1d23d9fc8d8 |
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 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
10 version.
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
20 02111-1307, USA. */
44 /* Like PREFERRED_STACK_BOUNDARY but in units of bytes, not bits. */
45 #define STACK_BYTES (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT)
47 /* Data structure and subroutines used within expand_call. */
49 struct arg_data
50 {
51 /* Tree node for this argument. */
52 tree tree_value;
53 /* Mode for value; TYPE_MODE unless promoted. */
55 /* Current RTL value for argument, or 0 if it isn't precomputed. */
56 rtx value;
57 /* Initially-compute RTL value for argument; only for const functions. */
58 rtx initial_value;
59 /* Register to pass this argument in, 0 if passed on stack, or an
60 PARALLEL if the arg is to be copied into multiple non-contiguous
61 registers. */
62 rtx reg;
63 /* Register to pass this argument in when generating tail call sequence.
64 This is not the same register as for normal calls on machines with
65 register windows. */
66 rtx tail_call_reg;
67 /* If REG was promoted from the actual mode of the argument expression,
68 indicates whether the promotion is sign- or zero-extended. */
70 /* Number of registers to use. 0 means put the whole arg in registers.
71 Also 0 if not passed in registers. */
73 /* Nonzero if argument must be passed on stack.
74 Note that some arguments may be passed on the stack
75 even though pass_on_stack is zero, just because FUNCTION_ARG says so.
76 pass_on_stack identifies arguments that *cannot* go in registers. */
78 /* Some fields packaged up for locate_and_pad_parm. */
80 /* Location on the stack at which parameter should be stored. The store
81 has already been done if STACK == VALUE. */
82 rtx stack;
83 /* Location on the stack of the start of this argument slot. This can
84 differ from STACK if this arg pads downward. This location is known
85 to be aligned to FUNCTION_ARG_BOUNDARY. */
86 rtx stack_slot;
87 /* Place that this stack area has been saved, if needed. */
88 rtx save_area;
89 /* If an argument's alignment does not permit direct copying into registers,
90 copy in smaller-sized pieces into pseudos. These are stored in a
91 block pointed to by this field. The next field says how many
92 word-sized pseudos we made. */
95 };
97 /* A vector of one char per byte of stack space. A byte if nonzero if
98 the corresponding stack location has been used.
99 This vector is used to prevent a function call within an argument from
100 clobbering any stack already set up. */
103 /* Size of STACK_USAGE_MAP. */
106 /* A bitmap of virtual-incoming stack space. Bit is set if the corresponding
107 stack location's tail call argument has been already stored into the stack.
108 This bitmap is used to prevent sibling call optimization if function tries
109 to use parent's incoming argument slots when they have been already
110 overwritten with tail call arguments. */
113 /* stack_arg_under_construction is nonzero when an argument may be
114 initialized with a constructor call (including a C function that
115 returns a BLKmode struct) and expand_call must take special action
116 to make sure the object being constructed does not overlap the
117 argument list for the constructor call. */
122 CUMULATIVE_ARGS *);
151 #ifdef REG_PARM_STACK_SPACE
154 #endif
155 \f
156 /* Force FUNEXP into a form suitable for the address of a CALL,
157 and return that as an rtx. Also load the static chain register
158 if FNDECL is a nested function.
160 CALL_FUSAGE points to a variable holding the prospective
161 CALL_INSN_FUNCTION_USAGE information. */
163 rtx
166 {
167 /* Make a valid memory address and copy constants through pseudo-regs,
168 but not for a constant address if -fno-function-cse. */
170 /* If we are using registers for parameters, force the
171 function address into a register now. */
176 {
177 #ifndef NO_FUNCTION_CSE
180 #endif
181 }
184 {
190 }
193 }
195 /* Generate instructions to call function FUNEXP,
196 and optionally pop the results.
197 The CALL_INSN is the first insn generated.
199 FNDECL is the declaration node of the function. This is given to the
200 macro RETURN_POPS_ARGS to determine whether this function pops its own args.
202 FUNTYPE is the data type of the function. This is given to the macro
203 RETURN_POPS_ARGS to determine whether this function pops its own args.
204 We used to allow an identifier for library functions, but that doesn't
205 work when the return type is an aggregate type and the calling convention
206 says that the pointer to this aggregate is to be popped by the callee.
208 STACK_SIZE is the number of bytes of arguments on the stack,
209 ROUNDED_STACK_SIZE is that number rounded up to
210 PREFERRED_STACK_BOUNDARY; zero if the size is variable. This is
211 both to put into the call insn and to generate explicit popping
212 code if necessary.
214 STRUCT_VALUE_SIZE is the number of bytes wanted in a structure value.
215 It is zero if this call doesn't want a structure value.
217 NEXT_ARG_REG is the rtx that results from executing
218 FUNCTION_ARG (args_so_far, VOIDmode, void_type_node, 1)
219 just after all the args have had their registers assigned.
220 This could be whatever you like, but normally it is the first
221 arg-register beyond those used for args in this call,
222 or 0 if all the arg-registers are used in this call.
223 It is passed on to `gen_call' so you can put this info in the call insn.
225 VALREG is a hard register in which a value is returned,
226 or 0 if the call does not return a value.
228 OLD_INHIBIT_DEFER_POP is the value that `inhibit_defer_pop' had before
229 the args to this call were processed.
230 We restore `inhibit_defer_pop' to that value.
232 CALL_FUSAGE is either empty or an EXPR_LIST of USE expressions that
233 denote registers used by the called function. */
235 static void
237 tree funtype ATTRIBUTE_UNUSED,
238 HOST_WIDE_INT stack_size ATTRIBUTE_UNUSED,
239 HOST_WIDE_INT rounded_stack_size,
240 HOST_WIDE_INT struct_value_size ATTRIBUTE_UNUSED,
244 {
246 rtx call_insn;
249 #if defined (HAVE_call) && defined (HAVE_call_value)
250 rtx struct_value_size_rtx;
252 #endif
254 #ifdef CALL_POPS_ARGS
256 #endif
258 /* Ensure address is valid. SYMBOL_REF is already valid, so no need,
259 and we don't want to load it into a register as an optimization,
260 because prepare_call_address already did it if it should be done. */
264 #if defined (HAVE_sibcall_pop) && defined (HAVE_sibcall_value_pop)
268 {
270 rtx pat;
272 /* If this subroutine pops its own args, record that in the call insn
273 if possible, for the sake of frame pointer elimination. */
279 n_pop);
280 else
286 }
287 else
288 #endif
290 #if defined (HAVE_call_pop) && defined (HAVE_call_value_pop)
291 /* If the target has "call" or "call_value" insns, then prefer them
292 if no arguments are actually popped. If the target does not have
293 "call" or "call_value" insns, then we must use the popping versions
294 even if the call has no arguments to pop. */
295 #if defined (HAVE_call) && defined (HAVE_call_value)
298 #else
300 #endif
301 {
303 rtx pat;
305 /* If this subroutine pops its own args, record that in the call insn
306 if possible, for the sake of frame pointer elimination. */
312 else
318 }
319 else
320 #endif
322 #if defined (HAVE_sibcall) && defined (HAVE_sibcall_value)
325 {
329 rounded_stack_size_rtx,
331 else
334 struct_value_size_rtx));
335 }
336 else
337 #endif
339 #if defined (HAVE_call) && defined (HAVE_call_value)
341 {
346 NULL_RTX));
347 else
350 struct_value_size_rtx));
351 }
352 else
353 #endif
356 /* Find the call we just emitted. */
359 /* Mark memory as used for "pure" function call. */
361 call_fusage
362 = gen_rtx_EXPR_LIST
366 call_fusage);
368 /* Put the register usage information there. */
371 /* If this is a const call, then set the insn's unchanging bit. */
375 /* If this call can't throw, attach a REG_EH_REGION reg note to that
376 effect. */
380 else
381 {
384 /* If rn < 0, then either (1) tree-ssa not used or (2) doesn't
385 throw, which we already took care of. */
390 }
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 LONGJMP for if the function is in the longjmp family.
468 Set MAY_BE_ALLOCA for any memory allocation function that might allocate
469 space from the stack such as alloca. */
471 static int
473 {
476 /* Exclude functions not at the file scope, or not `extern',
477 since they are not the magic functions we would otherwise
478 think they are.
479 FIXME: this should be handled with attributes, not with this
480 hacky imitation of DECL_ASSEMBLER_NAME. It's (also) wrong
481 because you can declare fork() inside a function if you
482 wish. */
486 {
490 /* We assume that alloca will always be called by name. It
491 makes no sense to pass it as a pointer-to-function to
492 anything that does not understand its behavior. */
501 /* Disregard prefix _, __ or __x. */
503 {
508 else
510 }
513 {
526 }
536 }
539 }
541 /* Return nonzero when tree represent call to longjmp. */
543 int
545 {
547 }
549 /* Return true when exp contains alloca call. */
550 bool
552 {
561 }
563 /* Detect flags (function attributes) from the function decl or type node. */
565 int
567 {
572 {
577 {
582 }
584 /* The function exp may have the `malloc' attribute. */
588 /* The function exp may have the `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
648 {
655 {
659 {
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 the value is expensive, and we are inside an appropriately
683 short loop, put the value into a pseudo and then put the pseudo
684 into the hard reg.
686 For small register classes, also do this if this call uses
687 register parameters. This is to avoid reload conflicts while
688 loading the parameters registers. */
698 }
699 }
701 #ifdef REG_PARM_STACK_SPACE
703 /* The argument list is the property of the called routine and it
704 may clobber it. If the fixed area has been used for previous
705 parameters, we must save and restore it. */
707 static rtx
708 save_fixed_argument_area (int reg_parm_stack_space, rtx argblock, int *low_to_save, int *high_to_save)
709 {
713 /* Compute the boundary of the area that needs to be saved, if any. */
715 #ifdef ARGS_GROW_DOWNWARD
717 #endif
723 {
727 rtx stack_area;
728 rtx save_area;
731 ;
739 /* If we don't have the required alignment, must do this
740 in BLKmode. */
745 #ifdef ARGS_GROW_DOWNWARD
747 #else
749 #endif
753 delta)));
757 {
761 }
762 else
763 {
766 }
769 }
772 }
774 static void
776 {
779 rtx stack_area;
781 #ifdef ARGS_GROW_DOWNWARD
783 #else
785 #endif
793 else
796 BLOCK_OP_CALL_PARM);
797 }
800 /* If any elements in ARGS refer to parameters that are to be passed in
801 registers, but not in memory, and whose alignment does not permit a
802 direct copy into registers. Copy the values into a group of pseudos
803 which we will later copy into the appropriate hard registers.
805 Pseudos for each unaligned argument will be stored into the array
806 args[argnum].aligned_regs. The caller is responsible for deallocating
807 the aligned_regs array if it is nonzero. */
809 static void
811 {
819 {
827 /* Structures smaller than a word are normally aligned to the
828 least significant byte. On a BYTES_BIG_ENDIAN machine,
829 this means we must skip the empty high order bytes when
830 calculating the bit offset. */
832 #ifdef BLOCK_REG_PADDING
836 #else
837 && BYTES_BIG_ENDIAN
838 #endif
839 )
843 {
852 /* There is no need to restrict this code to loading items
853 in TYPE_ALIGN sized hunks. The bitfield instructions can
854 load up entire word sized registers efficiently.
856 ??? This may not be needed anymore.
857 We use to emit a clobber here but that doesn't let later
858 passes optimize the instructions we emit. By storing 0 into
859 the register later passes know the first AND to zero out the
860 bitfield being set in the register is unnecessary. The store
861 of 0 will be deleted as will at least the first AND. */
867 word);
868 }
869 }
870 }
872 /* Fill in ARGS_SIZE and ARGS array based on the parameters found in
873 ACTPARMS.
875 NUM_ACTUALS is the total number of parameters.
877 N_NAMED_ARGS is the total number of named arguments.
879 FNDECL is the tree code for the target of this call (if known)
881 ARGS_SO_FAR holds state needed by the target to know where to place
882 the next argument.
884 REG_PARM_STACK_SPACE is the number of bytes of stack space reserved
885 for arguments which are passed in registers.
887 OLD_STACK_LEVEL is a pointer to an rtx which olds the old stack level
888 and may be modified by this routine.
890 OLD_PENDING_ADJ, MUST_PREALLOCATE and FLAGS are pointers to integer
891 flags which may may be modified by this routine.
893 MAY_TAILCALL is cleared if we encounter an invisible pass-by-reference
894 that requires allocation of stack space.
896 CALL_FROM_THUNK_P is true if this call is the jump from a thunk to
897 the thunked-to function. */
899 static void
910 {
911 /* 1 if scanning parms front to back, -1 if scanning back to front. */
914 /* Count arg position in order args appear. */
918 tree p;
923 /* In this loop, we consider args in the order they are written.
924 We fill up ARGS from the front or from the back if necessary
925 so that in any case the first arg to be pushed ends up at the front. */
928 {
930 /* In this case, must reverse order of args
931 so that we compute and push the last arg first. */
932 }
933 else
934 {
936 }
938 /* I counts args in order (to be) pushed; ARGPOS counts in order written. */
940 {
947 /* Replace erroneous argument with constant zero. */
951 /* If TYPE is a transparent union, pass things the way we would
952 pass the first field of the union. We have already verified that
953 the modes are the same. */
957 /* Decide where to pass this arg.
959 args[i].reg is nonzero if all or part is passed in registers.
961 args[i].partial is nonzero if part but not all is passed in registers,
962 and the exact value says how many words are passed in registers.
964 args[i].pass_on_stack is nonzero if the argument must at least be
965 computed on the stack. It may then be loaded back into registers
966 if args[i].reg is nonzero.
968 These decisions are driven by the FUNCTION_... macros and must agree
969 with those made by function.c. */
971 /* See if this argument should be passed by invisible reference. */
974 {
976 tree base;
978 callee_copies
982 /* If we're compiling a thunk, pass through invisible references
983 instead of making a copy. */
985 || (callee_copies
989 {
990 /* We can't use sibcalls if a callee-copied argument is
991 stored in the current function's frame. */
999 }
1000 else
1001 {
1002 /* We make a copy of the object and pass the address to the
1003 function being called. */
1004 rtx copy;
1010 STACK_CHECK_MAX_VAR_SIZE))))
1011 {
1012 /* This is a variable-sized object. Make space on the stack
1013 for it. */
1017 {
1021 }
1024 allocate_dynamic_stack_space
1027 }
1028 else
1035 else
1042 }
1043 }
1056 #ifdef FUNCTION_INCOMING_ARG
1057 /* If this is a sibling call and the machine has register windows, the
1058 register window has to be unwinded before calling the routine, so
1059 arguments have to go into the incoming registers. */
1062 #else
1064 #endif
1073 /* If FUNCTION_ARG returned a (parallel [(expr_list (nil) ...) ...]),
1074 it means that we are to pass this arg in the register(s) designated
1075 by the PARALLEL, but also to pass it in the stack. */
1080 /* If this is an addressable type, we must preallocate the stack
1081 since we must evaluate the object into its final location.
1083 If this is to be passed in both registers and the stack, it is simpler
1084 to preallocate. */
1089 /* If this is an addressable type, we cannot pre-evaluate it. Thus,
1090 we cannot consider this function call constant. */
1094 /* Compute the stack-size of this argument. */
1099 #ifdef STACK_PARMS_IN_REG_PARM_AREA
1101 #else
1103 #endif
1106 #ifdef BLOCK_REG_PADDING
1107 else
1108 /* The argument is passed entirely in registers. See at which
1109 end it should be padded. */
1113 #endif
1115 /* Update ARGS_SIZE, the total stack space for args so far. */
1121 /* Increment ARGS_SO_FAR, which has info about which arg-registers
1122 have been used, etc. */
1126 }
1127 }
1129 /* Update ARGS_SIZE to contain the total size for the argument block.
1130 Return the original constant component of the argument block's size.
1132 REG_PARM_STACK_SPACE holds the number of bytes of stack space reserved
1133 for arguments passed in registers. */
1135 static int
1139 {
1142 /* For accumulate outgoing args mode we don't need to align, since the frame
1143 will be already aligned. Align to STACK_BOUNDARY in order to prevent
1144 backends from generating misaligned frame sizes. */
1148 /* Compute the actual size of the argument block required. The variable
1149 and constant sizes must be combined, the size may have to be rounded,
1150 and there may be a minimum required size. */
1153 {
1159 {
1160 /* We don't handle this case yet. To handle it correctly we have
1161 to add the delta, round and subtract the delta.
1162 Currently no machine description requires this support. */
1165 }
1168 {
1169 args_size->var
1173 #ifndef OUTGOING_REG_PARM_STACK_SPACE
1174 /* The area corresponding to register parameters is not to count in
1175 the size of the block we need. So make the adjustment. */
1176 args_size->var
1179 #endif
1180 }
1181 }
1182 else
1183 {
1188 + stack_pointer_delta
1190 / preferred_stack_boundary
1195 reg_parm_stack_space);
1197 #ifndef OUTGOING_REG_PARM_STACK_SPACE
1199 #endif
1200 }
1202 }
1204 /* Precompute parameters as needed for a function call.
1206 FLAGS is mask of ECF_* constants.
1208 NUM_ACTUALS is the number of arguments.
1210 ARGS is an array containing information for each argument; this
1211 routine fills in the INITIAL_VALUE and VALUE fields for each
1212 precomputed argument. */
1214 static void
1216 {
1219 /* If this is a libcall, then precompute all arguments so that we do not
1220 get extraneous instructions emitted as part of the libcall sequence. */
1225 {
1228 /* If this is an addressable type, we cannot pre-evaluate it. */
1236 {
1240 #if defined(PROMOTE_FUNCTION_MODE) && !defined(PROMOTE_MODE)
1241 /* CSE will replace this only if it contains args[i].value
1242 pseudo, so convert it down to the declared mode using
1243 a SUBREG. */
1246 {
1252 }
1253 #endif
1254 }
1255 }
1256 }
1258 /* Given the current state of MUST_PREALLOCATE and information about
1259 arguments to a function call in NUM_ACTUALS, ARGS and ARGS_SIZE,
1260 compute and return the final value for MUST_PREALLOCATE. */
1262 static int
1263 finalize_must_preallocate (int must_preallocate, int num_actuals, struct arg_data *args, struct args_size *args_size)
1264 {
1265 /* See if we have or want to preallocate stack space.
1267 If we would have to push a partially-in-regs parm
1268 before other stack parms, preallocate stack space instead.
1270 If the size of some parm is not a multiple of the required stack
1271 alignment, we must preallocate.
1273 If the total size of arguments that would otherwise create a copy in
1274 a temporary (such as a CALL) is more than half the total argument list
1275 size, preallocation is faster.
1277 Another reason to preallocate is if we have a machine (like the m88k)
1278 where stack alignment is required to be maintained between every
1279 pair of insns, not just when the call is made. However, we assume here
1280 that such machines either do not have push insns (and hence preallocation
1281 would occur anyway) or the problem is taken care of with
1282 PUSH_ROUNDING. */
1285 {
1291 {
1302 copy_to_evaluate_size
1304 }
1309 }
1311 }
1313 /* If we preallocated stack space, compute the address of each argument
1314 and store it into the ARGS array.
1316 We need not ensure it is a valid memory address here; it will be
1317 validized when it is used.
1319 ARGBLOCK is an rtx for the address of the outgoing arguments. */
1321 static void
1323 {
1325 {
1333 {
1336 rtx addr;
1338 /* Skip this parm if it will not be passed on the stack. */
1344 else
1355 else
1364 /* Function incoming arguments may overlap with sibling call
1365 outgoing arguments and we cannot allow reordering of reads
1366 from function arguments with stores to outgoing arguments
1367 of sibling calls. */
1370 }
1371 }
1372 }
1374 /* Given a FNDECL and EXP, return an rtx suitable for use as a target address
1375 in a call instruction.
1377 FNDECL is the tree node for the target function. For an indirect call
1378 FNDECL will be NULL_TREE.
1380 ADDR is the operand 0 of CALL_EXPR for this call. */
1382 static rtx
1384 {
1385 rtx funexp;
1387 /* Get the function to call, in the form of RTL. */
1389 {
1390 /* If this is the first use of the function, see if we need to
1391 make an external definition for it. */
1393 {
1396 }
1398 /* Get a SYMBOL_REF rtx for the function address. */
1400 }
1401 else
1402 /* Generate an rtx (probably a pseudo-register) for the address. */
1403 {
1407 }
1409 }
1411 /* Do the register loads required for any wholly-register parms or any
1412 parms which are passed both on the stack and in a register. Their
1413 expressions were already evaluated.
1415 Mark all register-parms as living through the call, putting these USE
1416 insns in the CALL_INSN_FUNCTION_USAGE field.
1418 When IS_SIBCALL, perform the check_sibcall_overlap_argument_overlap
1419 checking, setting *SIBCALL_FAILURE if appropriate. */
1421 static void
1425 {
1429 {
1433 {
1438 /* Set to non-negative if must move a word at a time, even if just
1439 one word (e.g, partial == 1 && mode == DFmode). Set to -1 if
1440 we just use a normal move insn. This value can be zero if the
1441 argument is a zero size structure with no fields. */
1446 {
1449 }
1450 else
1453 /* Handle calls that pass values in multiple non-contiguous
1454 locations. The Irix 6 ABI has examples of this. */
1457 {
1461 }
1463 /* If simple case, just do move. If normal partial, store_one_arg
1464 has already loaded the register for us. In all other cases,
1465 load the register(s) from memory. */
1468 {
1470 #ifdef BLOCK_REG_PADDING
1471 /* Handle case where we have a value that needs shifting
1472 up to the msb. eg. a QImode value and we're padding
1473 upward on a BYTES_BIG_ENDIAN machine. */
1477 {
1478 rtx x;
1481 /* Assigning REG here rather than a temp makes CALL_FUSAGE
1482 report the whole reg as used. Strictly speaking, the
1483 call only uses SIZE bytes at the msb end, but it doesn't
1484 seem worth generating rtl to say that. */
1491 }
1492 #endif
1493 }
1495 /* If we have pre-computed the values to put in the registers in
1496 the case of non-aligned structures, copy them in now. */
1504 {
1507 /* Handle a BLKmode that needs shifting. */
1509 #ifdef BLOCK_REG_PADDING
1511 #else
1512 && BYTES_BIG_ENDIAN
1513 #endif
1514 )
1515 {
1529 }
1530 else
1532 }
1534 /* When a parameter is a block, and perhaps in other cases, it is
1535 possible that it did a load from an argument slot that was
1536 already clobbered. */
1541 /* Handle calls that pass values in multiple non-contiguous
1542 locations. The Irix 6 ABI has examples of this. */
1547 else
1549 }
1550 }
1551 }
1553 /* We need to pop PENDING_STACK_ADJUST bytes. But, if the arguments
1554 wouldn't fill up an even multiple of PREFERRED_UNIT_STACK_BOUNDARY
1555 bytes, then we would need to push some additional bytes to pad the
1556 arguments. So, we compute an adjust to the stack pointer for an
1557 amount that will leave the stack under-aligned by UNADJUSTED_ARGS_SIZE
1558 bytes. Then, when the arguments are pushed the stack will be perfectly
1559 aligned. ARGS_SIZE->CONSTANT is set to the number of bytes that should
1560 be popped after the call. Returns the adjustment. */
1562 static int
1566 {
1567 /* The number of bytes to pop so that the stack will be
1568 under-aligned by UNADJUSTED_ARGS_SIZE bytes. */
1569 HOST_WIDE_INT adjustment;
1570 /* The alignment of the stack after the arguments are pushed, if we
1571 just pushed the arguments without adjust the stack here. */
1574 unadjusted_alignment
1578 /* We want to get rid of as many of the PENDING_STACK_ADJUST bytes
1579 as possible -- leaving just enough left to cancel out the
1580 UNADJUSTED_ALIGNMENT. In other words, we want to ensure that the
1581 PENDING_STACK_ADJUST is non-negative, and congruent to
1582 -UNADJUSTED_ALIGNMENT modulo the PREFERRED_UNIT_STACK_BOUNDARY. */
1584 /* Begin by trying to pop all the bytes. */
1585 unadjusted_alignment
1586 = (unadjusted_alignment
1589 /* Push enough additional bytes that the stack will be aligned
1590 after the arguments are pushed. */
1592 {
1595 else
1597 }
1599 /* Now, sets ARGS_SIZE->CONSTANT so that we pop the right number of
1600 bytes after the call. The right number is the entire
1601 PENDING_STACK_ADJUST less our ADJUSTMENT plus the amount required
1602 by the arguments in the first place. */
1603 args_size->constant
1607 }
1609 /* Scan X expression if it does not dereference any argument slots
1610 we already clobbered by tail call arguments (as noted in stored_args_map
1611 bitmap).
1612 Return nonzero if X expression dereferences such argument slots,
1613 zero otherwise. */
1615 static int
1617 {
1618 RTX_CODE code;
1629 {
1634 current_function_internal_arg_pointer
1637 else
1640 #ifdef ARGS_GROW_DOWNWARD
1642 #endif
1650 }
1652 /* Scan all subexpressions. */
1655 {
1657 {
1660 }
1662 {
1666 }
1667 }
1669 }
1671 /* Scan sequence after INSN if it does not dereference any argument slots
1672 we already clobbered by tail call arguments (as noted in stored_args_map
1673 bitmap). If MARK_STORED_ARGS_MAP, add stack slots for ARG to
1674 stored_args_map bitmap afterwards (when ARG is a register MARK_STORED_ARGS_MAP
1675 should be 0). Return nonzero if sequence after INSN dereferences such argument
1676 slots, zero otherwise. */
1678 static int
1680 {
1685 else
1694 {
1695 #ifdef ARGS_GROW_DOWNWARD
1697 #else
1699 #endif
1703 }
1705 }
1707 /* If function value *VALUE was returned at the most significant end of a
1708 register, shift it towards the least significant end and convert it to
1709 TYPE's mode. Return true and update *VALUE if some action was needed.
1711 TYPE is the type of the function's return value, which is known not
1712 to have mode BLKmode. */
1714 static bool
1716 {
1718 {
1719 HOST_WIDE_INT shift;
1724 {
1725 /* Shift the value into the low part of the register. */
1729 /* Truncate it to the type's mode, or its integer equivalent.
1730 This is subject to TRULY_NOOP_TRUNCATION. */
1734 /* Now convert it to the final form. */
1737 }
1738 }
1740 }
1742 /* Remove all REG_EQUIV notes found in the insn chain. */
1744 static void
1746 {
1747 rtx insn;
1750 {
1752 {
1755 {
1756 /* Remove the note and keep looking at the notes for
1757 this insn. */
1760 }
1762 }
1763 }
1764 }
1766 /* Generate all the code for a function call
1767 and return an rtx for its value.
1768 Store the value in TARGET (specified as an rtx) if convenient.
1769 If the value is stored in TARGET then TARGET is returned.
1770 If IGNORE is nonzero, then we ignore the value of the function call. */
1772 rtx
1774 {
1775 /* Nonzero if we are currently expanding a call. */
1778 /* List of actual parameters. */
1780 /* RTX for the function to be called. */
1781 rtx funexp;
1782 /* Sequence of insns to perform a normal "call". */
1784 /* Sequence of insns to perform a tail "call". */
1786 /* Data type of the function. */
1787 tree funtype;
1788 tree type_arg_types;
1789 /* Declaration of the function being called,
1790 or 0 if the function is computed (not known by name). */
1792 /* The type of the function being called. */
1793 tree fntype;
1797 /* Register in which non-BLKmode value will be returned,
1798 or 0 if no value or if value is BLKmode. */
1799 rtx valreg;
1800 /* Address where we should return a BLKmode value;
1801 0 if value not BLKmode. */
1803 /* Nonzero if that address is being passed by treating it as
1804 an extra, implicit first parameter. Otherwise,
1805 it is passed by being copied directly into struct_value_rtx. */
1807 /* Size of aggregate value wanted, or zero if none wanted
1808 or if we are using the non-reentrant PCC calling convention
1809 or expecting the value in registers. */
1811 /* Nonzero if called function returns an aggregate in memory PCC style,
1812 by returning the address of where to find it. */
1816 /* Number of actual parameters in this call, including struct value addr. */
1818 /* Number of named args. Args after this are anonymous ones
1819 and they must all go on the stack. */
1822 /* Vector of information about each argument.
1823 Arguments are numbered in the order they will be pushed,
1824 not the order they are written. */
1827 /* Total size in bytes of all the stack-parms scanned so far. */
1830 /* Size of arguments before any adjustments (such as rounding). */
1832 /* Data on reg parms scanned so far. */
1833 CUMULATIVE_ARGS args_so_far;
1834 /* Nonzero if a reg parm has been scanned. */
1836 /* Nonzero if this is an indirect function call. */
1838 /* Nonzero if we must avoid push-insns in the args for this call.
1839 If stack space is allocated for register parameters, but not by the
1840 caller, then it is preallocated in the fixed part of the stack frame.
1841 So the entire argument block must then be preallocated (i.e., we
1842 ignore PUSH_ROUNDING in that case). */
1846 /* Size of the stack reserved for parameter registers. */
1849 /* Address of space preallocated for stack parms
1850 (on machines that lack push insns), or 0 if space not preallocated. */
1853 /* Mask of ECF_ flags. */
1855 #ifdef REG_PARM_STACK_SPACE
1856 /* Define the boundary of the register parm stack space that needs to be
1857 saved, if any. */
1860 #endif
1867 /* State variables to track stack modifications. */
1873 /* Some stack pointer alterations we make are performed via
1874 allocate_dynamic_stack_space. This modifies the stack_pointer_delta,
1875 which we then also need to save/restore along the way. */
1878 rtx call_fusage;
1882 /* The alignment of the stack, in bits. */
1884 /* The alignment of the stack, in bytes. */
1886 /* The static chain value to use for this call. */
1887 rtx static_chain_value;
1888 /* See if this is "nothrow" function call. */
1892 /* See if we can find a DECL-node for the actual function, and get the
1893 function attributes (flags) from the function decl or type node. */
1896 {
1899 }
1900 else
1901 {
1904 }
1908 /* Warn if this value is an aggregate type,
1909 regardless of which calling convention we are using for it. */
1913 /* If the result of a pure or const function call is ignored (or void),
1914 and none of its arguments are volatile, we can avoid expanding the
1915 call and just evaluate the arguments for side-effects. */
1919 {
1921 tree arg;
1925 {
1928 }
1931 {
1936 }
1937 }
1939 #ifdef REG_PARM_STACK_SPACE
1941 #endif
1943 #ifndef OUTGOING_REG_PARM_STACK_SPACE
1946 #endif
1948 /* Set up a place to return a structure. */
1950 /* Cater to broken compilers. */
1952 {
1953 /* This call returns a big structure. */
1956 #ifdef PCC_STATIC_STRUCT_RETURN
1957 {
1959 }
1961 {
1965 {
1966 /* The structure value address arg is already in actparms.
1967 Pull it out. It might be nice to just leave it there, but
1968 we need to set structure_value_addr. */
1973 }
1976 else
1977 {
1978 /* For variable-sized objects, we must be called with a target
1979 specified. If we were to allocate space on the stack here,
1980 we would have no way of knowing when to free it. */
1986 }
1987 }
1989 }
1991 /* Figure out the amount to which the stack should be aligned. */
1994 {
1998 }
2000 /* Operand 0 is a pointer-to-function; get the type of the function. */
2005 /* Munge the tree to split complex arguments into their imaginary
2006 and real parts. */
2008 {
2011 }
2012 else
2018 /* If struct_value_rtx is 0, it means pass the address
2019 as if it were an extra parameter. */
2021 {
2022 /* If structure_value_addr is a REG other than
2023 virtual_outgoing_args_rtx, we can use always use it. If it
2024 is not a REG, we must always copy it into a register.
2025 If it is virtual_outgoing_args_rtx, we must copy it to another
2026 register in some cases. */
2028 || (ACCUMULATE_OUTGOING_ARGS
2029 && stack_arg_under_construction
2035 actparms
2038 temp),
2039 actparms);
2041 }
2043 /* Count the arguments and set NUM_ACTUALS. */
2045 num_actuals++;
2047 /* Compute number of named args.
2048 First, do a raw count of the args for INIT_CUMULATIVE_ARGS. */
2051 n_named_args
2053 /* Count the struct value address, if it is passed as a parm. */
2055 else
2056 /* If we know nothing, treat all args as named. */
2059 /* Start updating where the next arg would go.
2061 On some machines (such as the PA) indirect calls have a different
2062 calling convention than normal calls. The fourth argument in
2063 INIT_CUMULATIVE_ARGS tells the backend if this is an indirect call
2064 or not. */
2067 /* Now possibly adjust the number of named args.
2068 Normally, don't include the last named arg if anonymous args follow.
2069 We do include the last named arg if
2070 targetm.calls.strict_argument_naming() returns nonzero.
2071 (If no anonymous args follow, the result of list_length is actually
2072 one too large. This is harmless.)
2074 If targetm.calls.pretend_outgoing_varargs_named() returns
2075 nonzero, and targetm.calls.strict_argument_naming() returns zero,
2076 this machine will be able to place unnamed args that were passed
2077 in registers into the stack. So treat all args as named. This
2078 allows the insns emitting for a specific argument list to be
2079 independent of the function declaration.
2081 If targetm.calls.pretend_outgoing_varargs_named() returns zero,
2082 we do not have any reliable way to pass unnamed args in
2083 registers, so we must force them into memory. */
2087 ;
2090 /* Don't include the last named arg. */
2092 else
2093 /* Treat all args as named. */
2096 /* Make a vector to hold all the information about each arg. */
2100 /* Build up entries in the ARGS array, compute the size of the
2101 arguments into ARGS_SIZE, etc. */
2110 {
2111 /* If this function requires a variable-sized argument list, don't
2112 try to make a cse'able block for this call. We may be able to
2113 do this eventually, but it is too complicated to keep track of
2114 what insns go in the cse'able block and which don't. */
2118 }
2120 /* Now make final decision about preallocating stack space. */
2125 /* If the structure value address will reference the stack pointer, we
2126 must stabilize it. We don't need to do this if we know that we are
2127 not going to adjust the stack pointer in processing this call. */
2132 structure_value_addr))
2137 /* Tail calls can make things harder to debug, and we've traditionally
2138 pushed these optimizations into -O2. Don't try if we're already
2139 expanding a call, as that means we're an argument. Don't try if
2140 there's cleanups, as we know there's code to follow the call. */
2143 || !flag_optimize_sibling_calls
2148 /* Rest of purposes for tail call optimizations to fail. */
2150 #ifdef HAVE_sibcall_epilogue
2151 !HAVE_sibcall_epilogue
2152 #else
2153 1
2154 #endif
2155 || !try_tail_call
2156 /* Doing sibling call optimization needs some work, since
2157 structure_value_addr can be allocated on the stack.
2158 It does not seem worth the effort since few optimizable
2159 sibling calls will return a structure. */
2161 /* Check whether the target is able to optimize the call
2162 into a sibcall. */
2164 /* Functions that do not return exactly once may not be sibcall
2165 optimized. */
2168 /* If the called function is nested in the current one, it might access
2169 some of the caller's arguments, but could clobber them beforehand if
2170 the argument areas are shared. */
2172 /* If this function requires more stack slots than the current
2173 function, we cannot change it into a sibling call. */
2175 /* If the callee pops its own arguments, then it must pop exactly
2176 the same number of arguments as the current function. */
2180 current_function_args_size))
2184 /* Ensure current function's preferred stack boundary is at least
2185 what we need. We don't have to increase alignment for recursive
2186 functions. */
2195 /* We want to make two insn chains; one for a sibling call, the other
2196 for a normal call. We will select one of the two chains after
2197 initial RTL generation is complete. */
2199 {
2201 /* We want to emit any pending stack adjustments before the tail
2202 recursion "call". That way we know any adjustment after the tail
2203 recursion call can be ignored if we indeed use the tail
2204 call expansion. */
2207 rtx insns;
2211 {
2212 /* State variables we need to save and restore between
2213 iterations. */
2216 }
2219 else
2222 /* Other state variables that we must reinitialize each time
2223 through the loop (that are not initialized by the loop itself). */
2227 /* Start a new sequence for the normal call case.
2229 From this point on, if the sibling call fails, we want to set
2230 sibcall_failure instead of continuing the loop. */
2233 /* Don't let pending stack adjusts add up to too much.
2234 Also, do all pending adjustments now if there is any chance
2235 this might be a call to alloca or if we are expanding a sibling
2236 call sequence or if we are calling a function that is to return
2237 with stack pointer depressed. */
2244 /* When calling a const function, we must pop the stack args right away,
2245 so that the pop is deleted or moved with the call. */
2247 NO_DEFER_POP;
2249 /* Precompute any arguments as needed. */
2253 /* Now we are about to start emitting insns that can be deleted
2254 if a libcall is deleted. */
2259 /* Compute the actual size of the argument block required. The variable
2260 and constant sizes must be combined, the size may have to be rounded,
2261 and there may be a minimum required size. When generating a sibcall
2262 pattern, do not round up, since we'll be re-using whatever space our
2263 caller provided. */
2264 unadjusted_args_size
2272 /* The argument block when performing a sibling call is the
2273 incoming argument block. */
2275 {
2277 argblock
2278 #ifdef STACK_GROWS_DOWNWARD
2280 #else
2282 #endif
2285 }
2287 /* If we have no actual push instructions, or shouldn't use them,
2288 make space for all args right now. */
2290 {
2292 {
2297 /* stack_arg_under_construction says whether a stack arg is
2298 being constructed at the old stack level. Pushing the stack
2299 gets a clean outgoing argument block. */
2302 }
2304 }
2305 else
2306 {
2307 /* Note that we must go through the motions of allocating an argument
2308 block even if the size is zero because we may be storing args
2309 in the area reserved for register arguments, which may be part of
2310 the stack frame. */
2314 /* Store the maximum argument space used. It will be pushed by
2315 the prologue (if ACCUMULATE_OUTGOING_ARGS, or stack overflow
2316 checking). */
2322 {
2324 {
2325 /* Since the stack pointer will never be pushed, it is
2326 possible for the evaluation of a parm to clobber
2327 something we have already written to the stack.
2328 Since most function calls on RISC machines do not use
2329 the stack, this is uncommon, but must work correctly.
2331 Therefore, we save any area of the stack that was already
2332 written and that we are using. Here we set up to do this
2333 by making a new stack usage map from the old one. The
2334 actual save will be done by store_one_arg.
2336 Another approach might be to try to reorder the argument
2337 evaluations to avoid this conflicting stack usage. */
2339 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2340 /* Since we will be writing into the entire argument area,
2341 the map must be allocated for its entire size, not just
2342 the part that is the responsibility of the caller. */
2344 #endif
2346 #ifdef ARGS_GROW_DOWNWARD
2349 #else
2351 needed);
2352 #endif
2357 initial_highest_arg_in_use);
2361 (highest_outgoing_arg_in_use
2365 /* The address of the outgoing argument list must not be
2366 copied to a register here, because argblock would be left
2367 pointing to the wrong place after the call to
2368 allocate_dynamic_stack_space below. */
2371 }
2372 else
2373 {
2375 {
2376 /* Try to reuse some or all of the pending_stack_adjust
2377 to get this space. */
2378 needed
2379 = (combine_pending_stack_adjustment_and_call
2382 preferred_unit_stack_boundary));
2384 /* combine_pending_stack_adjustment_and_call computes
2385 an adjustment before the arguments are allocated.
2386 Account for them and see whether or not the stack
2387 needs to go up or down. */
2391 {
2392 /* We're releasing stack space. */
2393 /* ??? We can avoid any adjustment at all if we're
2394 already aligned. FIXME. */
2398 }
2399 else
2400 /* We need to allocate space. We'll do that in
2401 push_block below. */
2403 }
2405 /* Special case this because overhead of `push_block' in
2406 this case is non-trivial. */
2409 else
2410 {
2412 #ifdef ARGS_GROW_DOWNWARD
2414 #endif
2415 }
2417 /* We only really need to call `copy_to_reg' in the case
2418 where push insns are going to be used to pass ARGBLOCK
2419 to a function call in ARGS. In that case, the stack
2420 pointer changes value from the allocation point to the
2421 call point, and hence the value of
2422 VIRTUAL_OUTGOING_ARGS_RTX changes as well. But might
2423 as well always do it. */
2425 }
2426 }
2427 }
2430 {
2431 /* The save/restore code in store_one_arg handles all
2432 cases except one: a constructor call (including a C
2433 function returning a BLKmode struct) to initialize
2434 an argument. */
2436 {
2437 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2440 #else
2442 #endif
2444 {
2446 NULL_RTX);
2450 /* stack_arg_under_construction says whether a stack
2451 arg is being constructed at the old stack level.
2452 Pushing the stack gets a clean outgoing argument
2453 block. */
2454 old_stack_arg_under_construction
2457 /* Make a new map for the new argument list. */
2461 }
2463 BITS_PER_UNIT);
2464 }
2466 /* If argument evaluation might modify the stack pointer,
2467 copy the address of the argument list to a register. */
2470 {
2473 }
2474 }
2478 /* If we push args individually in reverse order, perform stack alignment
2479 before the first push (the last arg). */
2482 {
2483 /* When the stack adjustment is pending, we get better code
2484 by combining the adjustments. */
2488 {
2489 pending_stack_adjust
2490 = (combine_pending_stack_adjustment_and_call
2493 preferred_unit_stack_boundary));
2495 }
2499 }
2500 /* Now that the stack is properly aligned, pops can't safely
2501 be deferred during the evaluation of the arguments. */
2502 NO_DEFER_POP;
2506 /* Figure out the register where the value, if any, will come back. */
2510 {
2514 else
2516 }
2518 /* Precompute all register parameters. It isn't safe to compute anything
2519 once we have started filling any specific hard regs. */
2525 else
2528 #ifdef REG_PARM_STACK_SPACE
2529 /* Save the fixed argument area if it's part of the caller's frame and
2530 is clobbered by argument setup for this call. */
2534 #endif
2536 /* Now store (and compute if necessary) all non-register parms.
2537 These come before register parms, since they can require block-moves,
2538 which could clobber the registers used for register parms.
2539 Parms which have partial registers are not stored here,
2540 but we do preallocate space here if they want that. */
2544 {
2549 reg_parm_stack_space)
2561 call_fusage);
2562 }
2564 /* If we have a parm that is passed in registers but not in memory
2565 and whose alignment does not permit a direct copy into registers,
2566 make a group of pseudos that correspond to each register that we
2567 will later fill. */
2571 /* Now store any partially-in-registers parm.
2572 This is the last place a block-move can happen. */
2576 {
2581 reg_parm_stack_space)
2586 }
2588 /* If we pushed args in forward order, perform stack alignment
2589 after pushing the last arg. */
2594 /* If register arguments require space on the stack and stack space
2595 was not preallocated, allocate stack space here for arguments
2596 passed in registers. */
2597 #ifdef OUTGOING_REG_PARM_STACK_SPACE
2601 #endif
2603 /* Pass the function the address in which to return a
2604 structure value. */
2606 {
2607 structure_value_addr
2612 NULL_RTX)));
2616 }
2624 /* Save a pointer to the last insn before the call, so that we can
2625 later safely search backwards to find the CALL_INSN. */
2628 /* Set up next argument register. For sibling calls on machines
2629 with register windows this should be the incoming register. */
2630 #ifdef FUNCTION_INCOMING_ARG
2634 else
2635 #endif
2639 /* All arguments and registers used for the call must be set up by
2640 now! */
2642 /* Stack must be properly aligned now. */
2646 /* Generate the actual call instruction. */
2652 /* If call is cse'able, make appropriate pair of reg-notes around it.
2653 Test valreg so we don't crash; may safely ignore `const'
2654 if return type is void. Disable for PARALLEL return values, because
2655 we have no way to move such values into a pseudo register. */
2657 {
2658 rtx insns;
2659 rtx insn;
2664 /* Expansion of block moves possibly introduced a loop that may
2665 not appear inside libcall block. */
2671 {
2674 }
2675 else
2676 {
2680 /* Mark the return value as a pointer if needed. */
2687 && fndecl
2695 else
2696 {
2697 /* Construct an "equal form" for the value which
2698 mentions all the arguments in order as well as
2699 the function name. */
2710 note);
2711 }
2715 }
2716 }
2718 {
2722 /* The return value from a malloc-like function is a pointer. */
2728 /* The return value from a malloc-like function can not alias
2729 anything else. */
2734 /* Write out the sequence. */
2739 }
2741 /* For calls to `setjmp', etc., inform flow.c it should complain
2742 if nonvolatile values are live. For functions that cannot return,
2743 inform flow that control does not fall through. */
2746 {
2747 /* The barrier must be emitted
2748 immediately after the CALL_INSN. Some ports emit more
2749 than just a CALL_INSN above, so we must search for it here. */
2753 {
2755 /* There was no CALL_INSN? */
2757 }
2761 /* Stack adjustments after a noreturn call are dead code.
2762 However when NO_DEFER_POP is in effect, we must preserve
2763 stack_pointer_delta. */
2765 {
2768 }
2769 }
2774 /* If value type not void, return an rtx for the value. */
2780 {
2782 {
2783 target
2786 structure_value_addr));
2788 }
2789 }
2791 {
2792 /* This is the special C++ case where we need to
2793 know what the true target was. We take care to
2794 never use this value more than once in one expression. */
2798 }
2799 /* Handle calls that return values in multiple non-contiguous locations.
2800 The Irix 6 ABI has examples of this. */
2802 {
2804 {
2805 /* This will only be assigned once, so it can be readonly. */
2812 }
2818 /* We can not support sibling calls for this case. */
2820 }
2824 {
2825 /* TARGET and VALREG cannot be equal at this point because the
2826 latter would not have REG_FUNCTION_VALUE_P true, while the
2827 former would if it were referring to the same register.
2829 If they refer to the same register, this move will be a no-op,
2830 except when function inlining is being done. */
2833 /* If we are setting a MEM, this code must be executed. Since it is
2834 emitted after the call insn, sibcall optimization cannot be
2835 performed in that case. */
2838 }
2840 {
2843 /* We can not support sibling calls for this case. */
2845 }
2846 else
2847 {
2852 }
2855 {
2856 /* If we promoted this return value, make the proper SUBREG.
2857 TARGET might be const0_rtx here, so be careful. */
2861 {
2868 /* If we don't promote as expected, something is wrong. */
2874 {
2881 }
2885 }
2886 }
2888 /* If size of args is variable or this was a constructor call for a stack
2889 argument, restore saved stack-pointer value. */
2892 {
2901 }
2903 {
2904 #ifdef REG_PARM_STACK_SPACE
2908 #endif
2910 /* If we saved any argument areas, restore them. */
2913 {
2915 rtx stack_area
2922 else
2925 BLOCK_OP_CALL_PARM);
2926 }
2930 }
2932 /* If this was alloca, record the new stack level for nonlocal gotos.
2933 Check for the handler slots since we might not have a save area
2934 for non-local gotos. */
2939 /* Free up storage we no longer need. */
2948 {
2951 /* Restore the pending stack adjustment now that we have
2952 finished generating the sibling call sequence. */
2957 /* Prepare arg structure for next iteration. */
2959 {
2963 }
2966 }
2967 else
2968 {
2971 /* Verify that we've deallocated all the stack we used. */
2973 || (old_stack_allocated
2975 }
2977 /* If something prevents making this a sibling call,
2978 zero out the sequence. */
2981 else
2983 }
2985 /* If tail call production succeeded, we need to remove REG_EQUIV notes on
2986 arguments too, as argument area is now clobbered by the call. */
2988 {
2991 }
2992 else
2995 currently_expanding_call--;
2997 /* If this function returns with the stack pointer depressed, ensure
2998 this block saves and restores the stack pointer, show it was
2999 changed, and adjust for any outgoing arg space. */
3001 {
3005 }
3008 }
3010 /* A sibling call sequence invalidates any REG_EQUIV notes made for
3011 this function's incoming arguments.
3013 At the start of RTL generation we know the only REG_EQUIV notes
3014 in the rtl chain are those for incoming arguments, so we can safely
3015 flush any REG_EQUIV note.
3017 This is (slight) overkill. We could keep track of the highest
3018 argument we clobber and be more selective in removing notes, but it
3019 does not seem to be worth the effort. */
3020 void
3022 {
3024 }
3026 /* Traverse an argument list in VALUES and expand all complex
3027 arguments into their components. */
3028 static tree
3030 {
3031 tree p;
3033 /* Before allocating memory, check for the common case of no complex. */
3035 {
3040 }
3043 found:
3047 {
3049 tree complex_type;
3057 {
3058 tree subtype;
3072 /* Skip the newly created node. */
3074 }
3075 }
3078 }
3080 /* Traverse a list of TYPES and expand all complex types into their
3081 components. */
3082 static tree
3084 {
3085 tree p;
3087 /* Before allocating memory, check for the common case of no complex. */
3089 {
3094 }
3097 found:
3101 {
3106 {
3109 /* Rewrite complex type with component type. */
3113 /* Add another component type for the imaginary part. */
3118 /* Skip the newly created node. */
3120 }
3121 }
3124 }
3125 \f
3126 /* Output a library call to function FUN (a SYMBOL_REF rtx).
3127 The RETVAL parameter specifies whether return value needs to be saved, other
3128 parameters are documented in the emit_library_call function below. */
3130 static rtx
3134 {
3135 /* Total size in bytes of all the stack-parms scanned so far. */
3137 /* Size of arguments before any adjustments (such as rounding). */
3140 rtx fun;
3144 CUMULATIVE_ARGS args_so_far;
3145 struct arg
3146 {
3147 rtx value;
3149 rtx reg;
3152 rtx save_area;
3153 };
3158 rtx valreg;
3164 rtx before_call;
3167 #ifdef REG_PARM_STACK_SPACE
3168 /* Define the boundary of the register parm stack space that needs to be
3169 save, if any. */
3172 #endif
3174 /* Size of the stack reserved for parameter registers. */
3180 #ifdef REG_PARM_STACK_SPACE
3182 #endif
3184 /* By default, library functions can not throw. */
3188 {
3215 }
3218 /* Ensure current function's preferred stack boundary is at least
3219 what we need. */
3223 /* If this kind of value comes back in memory,
3224 decide where in memory it should come back. */
3226 {
3229 {
3230 #ifdef PCC_STATIC_STRUCT_RETURN
3231 rtx pointer_reg
3241 else
3243 #endif
3244 /* This call returns a big structure. */
3246 }
3247 }
3248 else
3251 /* ??? Unfinished: must pass the memory address as an argument. */
3253 /* Copy all the libcall-arguments out of the varargs data
3254 and into a vector ARGVEC.
3256 Compute how to pass each argument. We only support a very small subset
3257 of the full argument passing conventions to limit complexity here since
3258 library functions shouldn't have many args. */
3263 #ifdef INIT_CUMULATIVE_LIBCALL_ARGS
3265 #else
3267 #endif
3274 /* Now we are about to start emitting insns that can be deleted
3275 if a libcall is deleted. */
3281 /* If there's a structure value address to be passed,
3282 either pass it in the special place, or pass it as an extra argument. */
3284 {
3288 nargs++;
3290 /* Make sure it is a reasonable operand for a move or push insn. */
3304 #ifdef STACK_PARMS_IN_REG_PARM_AREA
3306 #else
3308 #endif
3317 count++;
3318 }
3321 {
3325 /* We cannot convert the arg value to the mode the library wants here;
3326 must do it earlier where we know the signedness of the arg. */
3330 /* Make sure it is a reasonable operand for a move or push insn. */
3336 {
3337 rtx slot;
3338 int must_copy
3341 /* loop.c won't look at CALL_INSN_FUNCTION_USAGE of const/pure
3342 functions, so we have to pretend this isn't such a function. */
3344 {
3348 }
3351 /* If this was a CONST function, it is now PURE since
3352 it now reads memory. */
3354 {
3357 }
3361 else
3362 {
3366 }
3370 call_fusage);
3374 slot),
3375 call_fusage);
3379 }
3390 #ifdef STACK_PARMS_IN_REG_PARM_AREA
3392 #else
3394 #endif
3405 }
3407 /* If this machine requires an external definition for library
3408 functions, write one out. */
3413 + stack_pointer_delta
3415 / STACK_BYTES
3420 reg_parm_stack_space);
3422 #ifndef OUTGOING_REG_PARM_STACK_SPACE
3424 #endif
3430 {
3431 /* Since the stack pointer will never be pushed, it is possible for
3432 the evaluation of a parm to clobber something we have already
3433 written to the stack. Since most function calls on RISC machines
3434 do not use the stack, this is uncommon, but must work correctly.
3436 Therefore, we save any area of the stack that was already written
3437 and that we are using. Here we set up to do this by making a new
3438 stack usage map from the old one.
3440 Another approach might be to try to reorder the argument
3441 evaluations to avoid this conflicting stack usage. */
3445 #ifndef OUTGOING_REG_PARM_STACK_SPACE
3446 /* Since we will be writing into the entire argument area, the
3447 map must be allocated for its entire size, not just the part that
3448 is the responsibility of the caller. */
3450 #endif
3452 #ifdef ARGS_GROW_DOWNWARD
3455 #else
3457 needed);
3458 #endif
3463 initial_highest_arg_in_use);
3470 /* We must be careful to use virtual regs before they're instantiated,
3471 and real regs afterwards. Loop optimization, for example, can create
3472 new libcalls after we've instantiated the virtual regs, and if we
3473 use virtuals anyway, they won't match the rtl patterns. */
3477 else
3479 }
3480 else
3481 {
3484 }
3486 /* If we push args individually in reverse order, perform stack alignment
3487 before the first push (the last arg). */
3493 {
3496 }
3497 else
3498 {
3501 }
3503 #ifdef REG_PARM_STACK_SPACE
3505 {
3506 /* The argument list is the property of the called routine and it
3507 may clobber it. If the fixed area has been used for previous
3508 parameters, we must save and restore it. */
3511 }
3512 #endif
3514 /* Push the args that need to be pushed. */
3516 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
3517 are to be pushed. */
3519 {
3527 {
3529 {
3530 /* If this is being stored into a pre-allocated, fixed-size,
3531 stack area, save any previous data at that location. */
3533 #ifdef ARGS_GROW_DOWNWARD
3534 /* stack_slot is negative, but we want to index stack_usage_map
3535 with positive values. */
3538 #else
3541 #endif
3544 /* Don't worry about things in the fixed argument area;
3545 it has already been saved. */
3549 i++;
3552 {
3553 /* We need to make a save area. */
3554 unsigned int size
3556 enum machine_mode save_mode
3558 rtx adr
3561 rtx stack_area
3565 {
3572 stack_area,
3574 BLOCK_OP_CALL_PARM);
3575 }
3576 else
3577 {
3581 }
3582 }
3583 }
3588 reg_parm_stack_space,
3591 /* Now mark the segment we just used. */
3596 NO_DEFER_POP;
3597 }
3598 }
3600 /* If we pushed args in forward order, perform stack alignment
3601 after pushing the last arg. */
3608 else
3613 /* Now load any reg parms into their regs. */
3615 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
3616 are to be pushed. */
3618 {
3624 /* Handle calls that pass values in multiple non-contiguous
3625 locations. The PA64 has examples of this for library calls. */
3631 NO_DEFER_POP;
3632 }
3634 /* Any regs containing parms remain in use through the call. */
3636 {
3642 }
3644 /* Pass the function the address in which to return a structure value. */
3646 {
3650 NULL_RTX)));
3653 }
3655 /* Don't allow popping to be deferred, since then
3656 cse'ing of library calls could delete a call and leave the pop. */
3657 NO_DEFER_POP;
3661 /* Stack must be properly aligned now. */
3667 /* We pass the old value of inhibit_defer_pop + 1 to emit_call_1, which
3668 will set inhibit_defer_pop to that value. */
3669 /* The return type is needed to decide how many bytes the function pops.
3670 Signedness plays no role in that, so for simplicity, we pretend it's
3671 always signed. We also assume that the list of arguments passed has
3672 no impact, so we pretend it is unknown. */
3678 struct_value_size,
3680 valreg,
3683 /* For calls to `setjmp', etc., inform flow.c it should complain
3684 if nonvolatile values are live. For functions that cannot return,
3685 inform flow that control does not fall through. */
3688 {
3689 /* The barrier note must be emitted
3690 immediately after the CALL_INSN. Some ports emit more than
3691 just a CALL_INSN above, so we must search for it here. */
3695 {
3697 /* There was no CALL_INSN? */
3699 }
3702 }
3704 /* Now restore inhibit_defer_pop to its actual original value. */
3705 OK_DEFER_POP;
3707 /* If call is cse'able, make appropriate pair of reg-notes around it.
3708 Test valreg so we don't crash; may safely ignore `const'
3709 if return type is void. Disable for PARALLEL return values, because
3710 we have no way to move such values into a pseudo register. */
3712 {
3713 rtx insns;
3716 {
3720 }
3721 else
3722 {
3724 rtx temp;
3728 {
3733 }
3737 /* Construct an "equal form" for the value which mentions all the
3738 arguments in order as well as the function name. */
3751 note);
3756 }
3757 }
3760 /* Copy the value to the right place. */
3762 {
3764 {
3769 }
3771 {
3775 }
3778 else
3780 }
3783 {
3784 #ifdef REG_PARM_STACK_SPACE
3788 #endif
3790 /* If we saved any argument areas, restore them. */
3793 {
3804 BLOCK_OP_CALL_PARM);
3805 else
3807 }
3811 }
3815 }
3816 \f
3817 /* Output a library call to function FUN (a SYMBOL_REF rtx)
3818 (emitting the queue unless NO_QUEUE is nonzero),
3819 for a value of mode OUTMODE,
3820 with NARGS different arguments, passed as alternating rtx values
3821 and machine_modes to convert them to.
3823 FN_TYPE should be LCT_NORMAL for `normal' calls, LCT_CONST for `const'
3824 calls, LCT_PURE for `pure' calls, LCT_CONST_MAKE_BLOCK for `const' calls
3825 which should be enclosed in REG_LIBCALL/REG_RETVAL notes,
3826 LCT_PURE_MAKE_BLOCK for `purep' calls which should be enclosed in
3827 REG_LIBCALL/REG_RETVAL notes with extra (use (memory (scratch)),
3828 or other LCT_ value for other types of library calls. */
3830 void
3833 {
3839 }
3840 \f
3841 /* Like emit_library_call except that an extra argument, VALUE,
3842 comes second and says where to store the result.
3843 (If VALUE is zero, this function chooses a convenient way
3844 to return the value.
3846 This function returns an rtx for where the value is to be found.
3847 If VALUE is nonzero, VALUE is returned. */
3849 rtx
3853 {
3854 rtx result;
3863 }
3864 \f
3865 /* Store a single argument for a function call
3866 into the register or memory area where it must be passed.
3867 *ARG describes the argument value and where to pass it.
3869 ARGBLOCK is the address of the stack-block for all the arguments,
3870 or 0 on a machine where arguments are pushed individually.
3872 MAY_BE_ALLOCA nonzero says this could be a call to `alloca'
3873 so must be careful about how the stack is used.
3875 VARIABLE_SIZE nonzero says that this was a variable-sized outgoing
3876 argument stack. This is used if ACCUMULATE_OUTGOING_ARGS to indicate
3877 that we need not worry about saving and restoring the stack.
3879 FNDECL is the declaration of the function we are calling.
3881 Return nonzero if this arg should cause sibcall failure,
3882 zero otherwise. */
3884 static int
3887 {
3898 /* Push a new temporary level for any temporaries we make for
3899 this argument. */
3903 {
3904 /* If this is being stored into a pre-allocated, fixed-size, stack area,
3905 save any previous data at that location. */
3907 {
3908 #ifdef ARGS_GROW_DOWNWARD
3909 /* stack_slot is negative, but we want to index stack_usage_map
3910 with positive values. */
3913 else
3917 #else
3920 else
3924 #endif
3927 /* Don't worry about things in the fixed argument area;
3928 it has already been saved. */
3932 i++;
3935 {
3936 /* We need to make a save area. */
3943 {
3952 BLOCK_OP_CALL_PARM);
3953 }
3954 else
3955 {
3958 }
3959 }
3960 }
3961 }
3963 /* If this isn't going to be placed on both the stack and in registers,
3964 set up the register and number of words. */
3966 {
3969 else
3972 }
3974 /* Being passed entirely in a register. We shouldn't be called in
3975 this case. */
3978 /* If this arg needs special alignment, don't load the registers
3979 here. */
3983 /* If this is being passed partially in a register, we can't evaluate
3984 it directly into its stack slot. Otherwise, we can. */
3986 {
3987 /* stack_arg_under_construction is nonzero if a function argument is
3988 being evaluated directly into the outgoing argument list and
3989 expand_call must take special action to preserve the argument list
3990 if it is called recursively.
3992 For scalar function arguments stack_usage_map is sufficient to
3993 determine which stack slots must be saved and restored. Scalar
3994 arguments in general have pass_on_stack == 0.
3996 If this argument is initialized by a function which takes the
3997 address of the argument (a C++ constructor or a C function
3998 returning a BLKmode structure), then stack_usage_map is
3999 insufficient and expand_call must push the stack around the
4000 function call. Such arguments have pass_on_stack == 1.
4002 Note that it is always safe to set stack_arg_under_construction,
4003 but this generates suboptimal code if set when not needed. */
4006 stack_arg_under_construction++;
4009 (partial
4014 /* If we are promoting object (or for any other reason) the mode
4015 doesn't agree, convert the mode. */
4022 stack_arg_under_construction--;
4023 }
4025 /* Don't allow anything left on stack from computation
4026 of argument to alloca. */
4031 /* If the value is already in the stack slot, we are done. */
4032 ;
4034 {
4037 /* Argument is a scalar, not entirely passed in registers.
4038 (If part is passed in registers, arg->partial says how much
4039 and emit_push_insn will take care of putting it there.)
4041 Push it, and if its size is less than the
4042 amount of space allocated to it,
4043 also bump stack pointer by the additional space.
4044 Note that in C the default argument promotions
4045 will prevent such mismatches. */
4048 /* Compute how much space the push instruction will push.
4049 On many machines, pushing a byte will advance the stack
4050 pointer by a halfword. */
4051 #ifdef PUSH_ROUNDING
4053 #endif
4056 /* Compute how much space the argument should get:
4057 round up to a multiple of the alignment for arguments. */
4063 /* This isn't already where we want it on the stack, so put it there.
4064 This can either be done with push or copy insns. */
4070 /* Unless this is a partially-in-register argument, the argument is now
4071 in the stack. */
4074 }
4075 else
4076 {
4077 /* BLKmode, at least partly to be pushed. */
4081 rtx size_rtx;
4083 /* Pushing a nonscalar.
4084 If part is passed in registers, PARTIAL says how much
4085 and emit_push_insn will take care of putting it there. */
4087 /* Round its size up to a multiple
4088 of the allocation unit for arguments. */
4091 {
4094 }
4095 else
4096 {
4097 /* PUSH_ROUNDING has no effect on us, because
4098 emit_push_insn for BLKmode is careful to avoid it. */
4100 {
4101 /* Use the size of the elt to compute excess. */
4106 }
4107 else
4113 }
4115 /* Some types will require stricter alignment, which will be
4116 provided for elsewhere in argument layout. */
4119 /* When an argument is padded down, the block is aligned to
4120 PARM_BOUNDARY, but the actual argument isn't. */
4122 {
4126 {
4129 }
4130 }
4133 {
4134 /* emit_push_insn might not work properly if arg->value and
4135 argblock + arg->locate.offset areas overlap. */
4142 current_function_internal_arg_pointer
4144 {
4148 /* expand_call should ensure this. */
4153 {
4156 }
4158 {
4161 }
4162 }
4163 }
4170 /* Unless this is a partially-in-register argument, the argument is now
4171 in the stack.
4173 ??? Unlike the case above, in which we want the actual
4174 address of the data, so that we can load it directly into a
4175 register, here we want the address of the stack slot, so that
4176 it's properly aligned for word-by-word copying or something
4177 like that. It's not clear that this is always correct. */
4180 }
4182 /* Mark all slots this store used. */
4188 /* Once we have pushed something, pops can't safely
4189 be deferred during the rest of the arguments. */
4190 NO_DEFER_POP;
4192 /* Free any temporary slots made in processing this argument. Show
4193 that we might have taken the address of something and pushed that
4194 as an operand. */
4200 }
4202 /* Nonzero if we do not know how to pass TYPE solely in registers. */
4204 bool
4206 tree type)
4207 {
4211 /* If the type has variable size... */
4215 /* If the type is marked as addressable (it is required
4216 to be constructed into the stack)... */
4221 }
4223 /* Another version of the TARGET_MUST_PASS_IN_STACK hook. This one
4224 takes trailing padding of a structure into account. */
4225 /* ??? Should be able to merge these two by examining BLOCK_REG_PADDING. */
4227 bool
4229 {
4233 /* If the type has variable size... */
4237 /* If the type is marked as addressable (it is required
4238 to be constructed into the stack)... */
4242 /* If the padding and mode of the type is such that a copy into
4243 a register would put it into the wrong part of the register. */
4251 }