| blob | 0d429f657670f81be113f669f15b744d15f46d6c |
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. */
125 CUMULATIVE_ARGS *);
154 #ifdef REG_PARM_STACK_SPACE
157 #endif
158 \f
159 /* If WHICH is 1, return 1 if EXP contains a call to the built-in function
160 `alloca'.
162 If WHICH is 0, return 1 if EXP contains a call to any function.
163 Actually, we only need return 1 if evaluating EXP would require pushing
164 arguments on the stack, but that is too difficult to compute, so we just
165 assume any function call might require the stack. */
169 static int
171 {
178 }
180 /* Recursive function to do the work of above function. */
182 static int
184 {
190 /* If this code is language-specific, we don't know what it will do. */
195 {
201 && (TYPE_RETURNS_STACK_DEPRESSED
215 {
216 tree tem;
221 }
231 calls_function_save_exprs);
236 {
237 tree local;
238 tree subblock;
246 subblock;
250 }
261 }
263 /* Only expressions and blocks can contain calls. */
273 }
274 \f
275 /* Force FUNEXP into a form suitable for the address of a CALL,
276 and return that as an rtx. Also load the static chain register
277 if FNDECL is a nested function.
279 CALL_FUSAGE points to a variable holding the prospective
280 CALL_INSN_FUNCTION_USAGE information. */
282 rtx
285 {
291 /* Get possible static chain value for nested function in C. */
294 /* Make a valid memory address and copy constants through pseudo-regs,
295 but not for a constant address if -fno-function-cse. */
297 /* If we are using registers for parameters, force the
298 function address into a register now. */
303 {
304 #ifndef NO_FUNCTION_CSE
306 #ifdef NO_RECURSIVE_FUNCTION_CSE
308 #endif
310 #endif
311 }
314 {
319 }
322 }
324 /* Generate instructions to call function FUNEXP,
325 and optionally pop the results.
326 The CALL_INSN is the first insn generated.
328 FNDECL is the declaration node of the function. This is given to the
329 macro RETURN_POPS_ARGS to determine whether this function pops its own args.
331 FUNTYPE is the data type of the function. This is given to the macro
332 RETURN_POPS_ARGS to determine whether this function pops its own args.
333 We used to allow an identifier for library functions, but that doesn't
334 work when the return type is an aggregate type and the calling convention
335 says that the pointer to this aggregate is to be popped by the callee.
337 STACK_SIZE is the number of bytes of arguments on the stack,
338 ROUNDED_STACK_SIZE is that number rounded up to
339 PREFERRED_STACK_BOUNDARY; zero if the size is variable. This is
340 both to put into the call insn and to generate explicit popping
341 code if necessary.
343 STRUCT_VALUE_SIZE is the number of bytes wanted in a structure value.
344 It is zero if this call doesn't want a structure value.
346 NEXT_ARG_REG is the rtx that results from executing
347 FUNCTION_ARG (args_so_far, VOIDmode, void_type_node, 1)
348 just after all the args have had their registers assigned.
349 This could be whatever you like, but normally it is the first
350 arg-register beyond those used for args in this call,
351 or 0 if all the arg-registers are used in this call.
352 It is passed on to `gen_call' so you can put this info in the call insn.
354 VALREG is a hard register in which a value is returned,
355 or 0 if the call does not return a value.
357 OLD_INHIBIT_DEFER_POP is the value that `inhibit_defer_pop' had before
358 the args to this call were processed.
359 We restore `inhibit_defer_pop' to that value.
361 CALL_FUSAGE is either empty or an EXPR_LIST of USE expressions that
362 denote registers used by the called function. */
364 static void
366 HOST_WIDE_INT stack_size ATTRIBUTE_UNUSED,
367 HOST_WIDE_INT rounded_stack_size,
368 HOST_WIDE_INT struct_value_size ATTRIBUTE_UNUSED,
372 {
374 rtx call_insn;
377 #if defined (HAVE_call) && defined (HAVE_call_value)
378 rtx struct_value_size_rtx;
380 #endif
382 #ifdef CALL_POPS_ARGS
384 #endif
386 /* Ensure address is valid. SYMBOL_REF is already valid, so no need,
387 and we don't want to load it into a register as an optimization,
388 because prepare_call_address already did it if it should be done. */
392 #if defined (HAVE_sibcall_pop) && defined (HAVE_sibcall_value_pop)
396 {
398 rtx pat;
400 /* If this subroutine pops its own args, record that in the call insn
401 if possible, for the sake of frame pointer elimination. */
407 n_pop);
408 else
414 }
415 else
416 #endif
418 #if defined (HAVE_call_pop) && defined (HAVE_call_value_pop)
419 /* If the target has "call" or "call_value" insns, then prefer them
420 if no arguments are actually popped. If the target does not have
421 "call" or "call_value" insns, then we must use the popping versions
422 even if the call has no arguments to pop. */
423 #if defined (HAVE_call) && defined (HAVE_call_value)
426 #else
428 #endif
429 {
431 rtx pat;
433 /* If this subroutine pops its own args, record that in the call insn
434 if possible, for the sake of frame pointer elimination. */
440 else
446 }
447 else
448 #endif
450 #if defined (HAVE_sibcall) && defined (HAVE_sibcall_value)
453 {
457 rounded_stack_size_rtx,
459 else
462 struct_value_size_rtx));
463 }
464 else
465 #endif
467 #if defined (HAVE_call) && defined (HAVE_call_value)
469 {
474 NULL_RTX));
475 else
478 struct_value_size_rtx));
479 }
480 else
481 #endif
484 /* Find the call we just emitted. */
487 /* Mark memory as used for "pure" function call. */
489 call_fusage
490 = gen_rtx_EXPR_LIST
494 call_fusage);
496 /* Put the register usage information there. */
499 /* If this is a const call, then set the insn's unchanging bit. */
503 /* If this call can't throw, attach a REG_EH_REGION reg note to that
504 effect. */
508 else
519 {
523 }
527 /* Restore this now, so that we do defer pops for this call's args
528 if the context of the call as a whole permits. */
532 {
541 }
544 {
545 /* If returning from the subroutine does not automatically pop the args,
546 we need an instruction to pop them sooner or later.
547 Perhaps do it now; perhaps just record how much space to pop later.
549 If returning from the subroutine does pop the args, indicate that the
550 stack pointer will be changed. */
553 {
555 /* Just pretend we did the pop. */
560 else
562 }
563 }
564 /* When we accumulate outgoing args, we must avoid any stack manipulations.
565 Restore the stack pointer to its original value now. Usually
566 ACCUMULATE_OUTGOING_ARGS targets don't get here, but there are exceptions.
567 On i386 ACCUMULATE_OUTGOING_ARGS can be enabled on demand, and
568 popping variants of functions exist as well.
570 ??? We may optimize similar to defer_pop above, but it is
571 probably not worthwhile.
573 ??? It will be worthwhile to enable combine_stack_adjustments even for
574 such machines. */
577 }
579 /* Determine if the function identified by NAME and FNDECL is one with
580 special properties we wish to know about.
582 For example, if the function might return more than one time (setjmp), then
583 set RETURNS_TWICE to a nonzero value.
585 Similarly set LONGJMP for if the function is in the longjmp family.
587 Set MAY_BE_ALLOCA for any memory allocation function that might allocate
588 space from the stack such as alloca. */
590 static int
592 {
596 /* Exclude functions not at the file scope, or not `extern',
597 since they are not the magic functions we would otherwise
598 think they are.
599 FIXME: this should be handled with attributes, not with this
600 hacky imitation of DECL_ASSEMBLER_NAME. It's (also) wrong
601 because you can declare fork() inside a function if you
602 wish. */
606 {
610 /* We assume that alloca will always be called by name. It
611 makes no sense to pass it as a pointer-to-function to
612 anything that does not understand its behavior. */
621 /* Disregard prefix _, __ or __x. */
623 {
628 else
630 }
633 {
646 }
659 /* Linux specific: __clone. check NAME to insist on the
660 leading underscores, to avoid polluting the ISO / POSIX
661 namespace. */
670 }
672 }
674 /* Return nonzero when tree represent call to longjmp. */
676 int
678 {
680 }
682 /* Return true when exp contains alloca call. */
683 bool
685 {
694 }
696 /* Detect flags (function attributes) from the function decl or type node. */
698 int
700 {
705 {
710 {
715 }
717 /* The function exp may have the `malloc' attribute. */
721 /* The function exp may have the `pure' attribute. */
730 }
738 /* Mark if the function returns with the stack pointer depressed. We
739 cannot consider it pure or constant in that case. */
741 {
744 }
747 }
749 /* Detect flags from a CALL_EXPR. */
751 int
753 {
759 else
760 {
764 else
766 }
769 }
771 /* Precompute all register parameters as described by ARGS, storing values
772 into fields within the ARGS array.
774 NUM_ACTUALS indicates the total number elements in the ARGS array.
776 Set REG_PARM_SEEN if we encounter a register parameter. */
778 static void
780 {
787 {
791 {
798 /* ANSI doesn't require a sequence point here,
799 but PCC has one, so this will avoid some problems. */
801 }
803 /* If the value is a non-legitimate constant, force it into a
804 pseudo now. TLS symbols sometimes need a call to resolve. */
809 /* If we are to promote the function arg to a wider mode,
810 do it now. */
818 /* If the value is expensive, and we are inside an appropriately
819 short loop, put the value into a pseudo and then put the pseudo
820 into the hard reg.
822 For small register classes, also do this if this call uses
823 register parameters. This is to avoid reload conflicts while
824 loading the parameters registers. */
834 }
835 }
837 #ifdef REG_PARM_STACK_SPACE
839 /* The argument list is the property of the called routine and it
840 may clobber it. If the fixed area has been used for previous
841 parameters, we must save and restore it. */
843 static rtx
844 save_fixed_argument_area (int reg_parm_stack_space, rtx argblock, int *low_to_save, int *high_to_save)
845 {
849 /* Compute the boundary of the area that needs to be saved, if any. */
851 #ifdef ARGS_GROW_DOWNWARD
853 #endif
859 {
863 rtx stack_area;
864 rtx save_area;
867 ;
875 /* If we don't have the required alignment, must do this
876 in BLKmode. */
881 #ifdef ARGS_GROW_DOWNWARD
883 #else
885 #endif
889 delta)));
893 {
897 }
898 else
899 {
902 }
905 }
908 }
910 static void
912 {
915 rtx stack_area;
917 #ifdef ARGS_GROW_DOWNWARD
919 #else
921 #endif
929 else
932 BLOCK_OP_CALL_PARM);
933 }
936 /* If any elements in ARGS refer to parameters that are to be passed in
937 registers, but not in memory, and whose alignment does not permit a
938 direct copy into registers. Copy the values into a group of pseudos
939 which we will later copy into the appropriate hard registers.
941 Pseudos for each unaligned argument will be stored into the array
942 args[argnum].aligned_regs. The caller is responsible for deallocating
943 the aligned_regs array if it is nonzero. */
945 static void
947 {
955 {
963 /* Structures smaller than a word are normally aligned to the
964 least significant byte. On a BYTES_BIG_ENDIAN machine,
965 this means we must skip the empty high order bytes when
966 calculating the bit offset. */
968 #ifdef BLOCK_REG_PADDING
972 #else
973 && BYTES_BIG_ENDIAN
974 #endif
975 )
979 {
988 /* There is no need to restrict this code to loading items
989 in TYPE_ALIGN sized hunks. The bitfield instructions can
990 load up entire word sized registers efficiently.
992 ??? This may not be needed anymore.
993 We use to emit a clobber here but that doesn't let later
994 passes optimize the instructions we emit. By storing 0 into
995 the register later passes know the first AND to zero out the
996 bitfield being set in the register is unnecessary. The store
997 of 0 will be deleted as will at least the first AND. */
1004 }
1005 }
1006 }
1008 /* Fill in ARGS_SIZE and ARGS array based on the parameters found in
1009 ACTPARMS.
1011 NUM_ACTUALS is the total number of parameters.
1013 N_NAMED_ARGS is the total number of named arguments.
1015 FNDECL is the tree code for the target of this call (if known)
1017 ARGS_SO_FAR holds state needed by the target to know where to place
1018 the next argument.
1020 REG_PARM_STACK_SPACE is the number of bytes of stack space reserved
1021 for arguments which are passed in registers.
1023 OLD_STACK_LEVEL is a pointer to an rtx which olds the old stack level
1024 and may be modified by this routine.
1026 OLD_PENDING_ADJ, MUST_PREALLOCATE and FLAGS are pointers to integer
1027 flags which may may be modified by this routine.
1029 CALL_FROM_THUNK_P is true if this call is the jump from a thunk to
1030 the thunked-to function. */
1032 static void
1043 {
1044 /* 1 if scanning parms front to back, -1 if scanning back to front. */
1047 /* Count arg position in order args appear. */
1051 tree p;
1056 /* In this loop, we consider args in the order they are written.
1057 We fill up ARGS from the front or from the back if necessary
1058 so that in any case the first arg to be pushed ends up at the front. */
1061 {
1063 /* In this case, must reverse order of args
1064 so that we compute and push the last arg first. */
1065 }
1066 else
1067 {
1069 }
1071 /* I counts args in order (to be) pushed; ARGPOS counts in order written. */
1073 {
1080 /* Replace erroneous argument with constant zero. */
1084 /* If TYPE is a transparent union, pass things the way we would
1085 pass the first field of the union. We have already verified that
1086 the modes are the same. */
1090 /* Decide where to pass this arg.
1092 args[i].reg is nonzero if all or part is passed in registers.
1094 args[i].partial is nonzero if part but not all is passed in registers,
1095 and the exact value says how many words are passed in registers.
1097 args[i].pass_on_stack is nonzero if the argument must at least be
1098 computed on the stack. It may then be loaded back into registers
1099 if args[i].reg is nonzero.
1101 These decisions are driven by the FUNCTION_... macros and must agree
1102 with those made by function.c. */
1104 /* See if this argument should be passed by invisible reference. */
1107 #ifdef FUNCTION_ARG_PASS_BY_REFERENCE
1110 #endif
1111 )
1112 {
1113 /* If we're compiling a thunk, pass through invisible
1114 references instead of making a copy. */
1116 #ifdef FUNCTION_ARG_CALLEE_COPIES
1119 /* If it's in a register, we must make a copy of it too. */
1120 /* ??? Is this a sufficient test? Is there a better one? */
1124 #endif
1125 )
1126 {
1127 /* C++ uses a TARGET_EXPR to indicate that we want to make a
1128 new object from the argument. If we are passing by
1129 invisible reference, the callee will do that for us, so we
1130 can strip off the TARGET_EXPR. This is not always safe,
1131 but it is safe in the only case where this is a useful
1132 optimization; namely, when the argument is a plain object.
1133 In that case, the frontend is just asking the backend to
1134 make a bitwise copy of the argument. */
1145 }
1147 {
1148 /* In the V3 C++ ABI, parameters are destroyed in the caller.
1149 We implement this by passing the address of the temporary
1150 rather than expanding it into another allocated slot. */
1155 }
1156 else
1157 {
1158 /* We make a copy of the object and pass the address to the
1159 function being called. */
1160 rtx copy;
1166 STACK_CHECK_MAX_VAR_SIZE))))
1167 {
1168 /* This is a variable-sized object. Make space on the stack
1169 for it. */
1173 {
1177 }
1180 allocate_dynamic_stack_space
1183 }
1184 else
1194 }
1195 }
1208 #ifdef FUNCTION_INCOMING_ARG
1209 /* If this is a sibling call and the machine has register windows, the
1210 register window has to be unwinded before calling the routine, so
1211 arguments have to go into the incoming registers. */
1214 #else
1216 #endif
1218 #ifdef FUNCTION_ARG_PARTIAL_NREGS
1223 #endif
1227 /* If FUNCTION_ARG returned a (parallel [(expr_list (nil) ...) ...]),
1228 it means that we are to pass this arg in the register(s) designated
1229 by the PARALLEL, but also to pass it in the stack. */
1234 /* If this is an addressable type, we must preallocate the stack
1235 since we must evaluate the object into its final location.
1237 If this is to be passed in both registers and the stack, it is simpler
1238 to preallocate. */
1243 /* If this is an addressable type, we cannot pre-evaluate it. Thus,
1244 we cannot consider this function call constant. */
1248 /* Compute the stack-size of this argument. */
1253 #ifdef STACK_PARMS_IN_REG_PARM_AREA
1255 #else
1257 #endif
1260 #ifdef BLOCK_REG_PADDING
1261 else
1262 /* The argument is passed entirely in registers. See at which
1263 end it should be padded. */
1267 #endif
1269 /* Update ARGS_SIZE, the total stack space for args so far. */
1275 /* Increment ARGS_SO_FAR, which has info about which arg-registers
1276 have been used, etc. */
1280 }
1281 }
1283 /* Update ARGS_SIZE to contain the total size for the argument block.
1284 Return the original constant component of the argument block's size.
1286 REG_PARM_STACK_SPACE holds the number of bytes of stack space reserved
1287 for arguments passed in registers. */
1289 static int
1293 {
1296 /* For accumulate outgoing args mode we don't need to align, since the frame
1297 will be already aligned. Align to STACK_BOUNDARY in order to prevent
1298 backends from generating misaligned frame sizes. */
1302 /* Compute the actual size of the argument block required. The variable
1303 and constant sizes must be combined, the size may have to be rounded,
1304 and there may be a minimum required size. */
1307 {
1313 {
1314 /* We don't handle this case yet. To handle it correctly we have
1315 to add the delta, round and subtract the delta.
1316 Currently no machine description requires this support. */
1320 }
1323 {
1324 args_size->var
1328 #ifndef OUTGOING_REG_PARM_STACK_SPACE
1329 /* The area corresponding to register parameters is not to count in
1330 the size of the block we need. So make the adjustment. */
1331 args_size->var
1334 #endif
1335 }
1336 }
1337 else
1338 {
1343 + stack_pointer_delta
1345 / preferred_stack_boundary
1350 reg_parm_stack_space);
1352 #ifndef OUTGOING_REG_PARM_STACK_SPACE
1354 #endif
1355 }
1357 }
1359 /* Precompute parameters as needed for a function call.
1361 FLAGS is mask of ECF_* constants.
1363 NUM_ACTUALS is the number of arguments.
1365 ARGS is an array containing information for each argument; this
1366 routine fills in the INITIAL_VALUE and VALUE fields for each
1367 precomputed argument. */
1369 static void
1371 {
1374 /* If this is a libcall, then precompute all arguments so that we do not
1375 get extraneous instructions emitted as part of the libcall sequence.
1377 If this target defines ACCUMULATE_OUTGOING_ARGS to true, then we must
1378 precompute all arguments that contain function calls. Otherwise,
1379 computing arguments for a subcall may clobber arguments for this call.
1381 If this target defines ACCUMULATE_OUTGOING_ARGS to false, then we only
1382 need to precompute arguments that change the stack pointer, such as calls
1383 to alloca, and calls that do not pop all of their arguments. */
1388 {
1391 /* If this is an addressable type, we cannot pre-evaluate it. */
1398 /* ANSI doesn't require a sequence point here,
1399 but PCC has one, so this will avoid some problems. */
1407 {
1411 #ifdef PROMOTE_FOR_CALL_ONLY
1412 /* CSE will replace this only if it contains args[i].value
1413 pseudo, so convert it down to the declared mode using
1414 a SUBREG. */
1417 {
1423 }
1424 #endif
1425 }
1426 }
1427 }
1429 /* Given the current state of MUST_PREALLOCATE and information about
1430 arguments to a function call in NUM_ACTUALS, ARGS and ARGS_SIZE,
1431 compute and return the final value for MUST_PREALLOCATE. */
1433 static int
1434 finalize_must_preallocate (int must_preallocate, int num_actuals, struct arg_data *args, struct args_size *args_size)
1435 {
1436 /* See if we have or want to preallocate stack space.
1438 If we would have to push a partially-in-regs parm
1439 before other stack parms, preallocate stack space instead.
1441 If the size of some parm is not a multiple of the required stack
1442 alignment, we must preallocate.
1444 If the total size of arguments that would otherwise create a copy in
1445 a temporary (such as a CALL) is more than half the total argument list
1446 size, preallocation is faster.
1448 Another reason to preallocate is if we have a machine (like the m88k)
1449 where stack alignment is required to be maintained between every
1450 pair of insns, not just when the call is made. However, we assume here
1451 that such machines either do not have push insns (and hence preallocation
1452 would occur anyway) or the problem is taken care of with
1453 PUSH_ROUNDING. */
1456 {
1462 {
1473 copy_to_evaluate_size
1475 }
1480 }
1482 }
1484 /* If we preallocated stack space, compute the address of each argument
1485 and store it into the ARGS array.
1487 We need not ensure it is a valid memory address here; it will be
1488 validized when it is used.
1490 ARGBLOCK is an rtx for the address of the outgoing arguments. */
1492 static void
1494 {
1496 {
1504 {
1507 rtx addr;
1509 /* Skip this parm if it will not be passed on the stack. */
1515 else
1526 else
1535 /* Function incoming arguments may overlap with sibling call
1536 outgoing arguments and we cannot allow reordering of reads
1537 from function arguments with stores to outgoing arguments
1538 of sibling calls. */
1541 }
1542 }
1543 }
1545 /* Given a FNDECL and EXP, return an rtx suitable for use as a target address
1546 in a call instruction.
1548 FNDECL is the tree node for the target function. For an indirect call
1549 FNDECL will be NULL_TREE.
1551 ADDR is the operand 0 of CALL_EXPR for this call. */
1553 static rtx
1555 {
1556 rtx funexp;
1558 /* Get the function to call, in the form of RTL. */
1560 {
1561 /* If this is the first use of the function, see if we need to
1562 make an external definition for it. */
1564 {
1567 }
1569 /* Get a SYMBOL_REF rtx for the function address. */
1571 }
1572 else
1573 /* Generate an rtx (probably a pseudo-register) for the address. */
1574 {
1579 }
1581 }
1583 /* Do the register loads required for any wholly-register parms or any
1584 parms which are passed both on the stack and in a register. Their
1585 expressions were already evaluated.
1587 Mark all register-parms as living through the call, putting these USE
1588 insns in the CALL_INSN_FUNCTION_USAGE field.
1590 When IS_SIBCALL, perform the check_sibcall_overlap_argument_overlap
1591 checking, setting *SIBCALL_FAILURE if appropriate. */
1593 static void
1597 {
1601 {
1605 {
1610 /* Set to non-negative if must move a word at a time, even if just
1611 one word (e.g, partial == 1 && mode == DFmode). Set to -1 if
1612 we just use a normal move insn. This value can be zero if the
1613 argument is a zero size structure with no fields. */
1618 {
1621 }
1622 else
1625 /* Handle calls that pass values in multiple non-contiguous
1626 locations. The Irix 6 ABI has examples of this. */
1629 {
1633 }
1635 /* If simple case, just do move. If normal partial, store_one_arg
1636 has already loaded the register for us. In all other cases,
1637 load the register(s) from memory. */
1640 {
1642 #ifdef BLOCK_REG_PADDING
1643 /* Handle case where we have a value that needs shifting
1644 up to the msb. eg. a QImode value and we're padding
1645 upward on a BYTES_BIG_ENDIAN machine. */
1649 {
1650 rtx x;
1653 /* Assigning REG here rather than a temp makes CALL_FUSAGE
1654 report the whole reg as used. Strictly speaking, the
1655 call only uses SIZE bytes at the msb end, but it doesn't
1656 seem worth generating rtl to say that. */
1662 }
1663 #endif
1664 }
1666 /* If we have pre-computed the values to put in the registers in
1667 the case of non-aligned structures, copy them in now. */
1675 {
1678 /* Handle a BLKmode that needs shifting. */
1680 #ifdef BLOCK_REG_PADDING
1682 #else
1683 && BYTES_BIG_ENDIAN
1684 #endif
1685 )
1686 {
1698 }
1699 else
1701 }
1703 /* When a parameter is a block, and perhaps in other cases, it is
1704 possible that it did a load from an argument slot that was
1705 already clobbered. */
1710 /* Handle calls that pass values in multiple non-contiguous
1711 locations. The Irix 6 ABI has examples of this. */
1716 else
1718 }
1719 }
1720 }
1722 /* Try to integrate function. See expand_inline_function for documentation
1723 about the parameters. */
1725 static rtx
1728 {
1729 rtx temp;
1730 rtx before_call;
1735 #ifdef REG_PARM_STACK_SPACE
1737 #endif
1745 structure_value_addr);
1749 /* If inlining succeeded, return. */
1751 {
1753 {
1754 /* If the outgoing argument list must be preserved, push
1755 the stack before executing the inlined function if it
1756 makes any calls. */
1762 ;
1765 {
1766 rtx first_insn
1770 /* Look for a call in the inline function code.
1771 If DECL_STRUCT_FUNCTION (fndecl)->outgoing_args_size is
1772 nonzero then there is a call and it is not necessary
1773 to scan the insns. */
1781 {
1782 /* Reserve enough stack space so that the largest
1783 argument list of any function call in the inline
1784 function does not overlap the argument list being
1785 evaluated. This is usually an overestimate because
1786 allocate_dynamic_stack_space reserves space for an
1787 outgoing argument list in addition to the requested
1788 space, but there is no way to ask for stack space such
1789 that an argument list of a certain length can be
1790 safely constructed.
1792 Add the stack space reserved for register arguments, if
1793 any, in the inline function. What is really needed is the
1794 largest value of reg_parm_stack_space in the inline
1795 function, but that is not available. Using the current
1796 value of reg_parm_stack_space is wrong, but gives
1797 correct results on all supported machines. */
1811 }
1812 }
1813 }
1815 /* If the result is equivalent to TARGET, return TARGET to simplify
1816 checks in store_expr. They can be equivalent but not equal in the
1817 case of a function that returns BLKmode. */
1821 }
1823 /* If inlining failed, mark FNDECL as needing to be compiled
1824 separately after all. If function was declared inline,
1825 give a warning. */
1828 {
1831 }
1834 }
1836 /* We need to pop PENDING_STACK_ADJUST bytes. But, if the arguments
1837 wouldn't fill up an even multiple of PREFERRED_UNIT_STACK_BOUNDARY
1838 bytes, then we would need to push some additional bytes to pad the
1839 arguments. So, we compute an adjust to the stack pointer for an
1840 amount that will leave the stack under-aligned by UNADJUSTED_ARGS_SIZE
1841 bytes. Then, when the arguments are pushed the stack will be perfectly
1842 aligned. ARGS_SIZE->CONSTANT is set to the number of bytes that should
1843 be popped after the call. Returns the adjustment. */
1845 static int
1849 {
1850 /* The number of bytes to pop so that the stack will be
1851 under-aligned by UNADJUSTED_ARGS_SIZE bytes. */
1852 HOST_WIDE_INT adjustment;
1853 /* The alignment of the stack after the arguments are pushed, if we
1854 just pushed the arguments without adjust the stack here. */
1855 HOST_WIDE_INT unadjusted_alignment;
1857 unadjusted_alignment
1861 /* We want to get rid of as many of the PENDING_STACK_ADJUST bytes
1862 as possible -- leaving just enough left to cancel out the
1863 UNADJUSTED_ALIGNMENT. In other words, we want to ensure that the
1864 PENDING_STACK_ADJUST is non-negative, and congruent to
1865 -UNADJUSTED_ALIGNMENT modulo the PREFERRED_UNIT_STACK_BOUNDARY. */
1867 /* Begin by trying to pop all the bytes. */
1868 unadjusted_alignment
1869 = (unadjusted_alignment
1872 /* Push enough additional bytes that the stack will be aligned
1873 after the arguments are pushed. */
1875 {
1878 else
1880 }
1882 /* Now, sets ARGS_SIZE->CONSTANT so that we pop the right number of
1883 bytes after the call. The right number is the entire
1884 PENDING_STACK_ADJUST less our ADJUSTMENT plus the amount required
1885 by the arguments in the first place. */
1886 args_size->constant
1890 }
1892 /* Scan X expression if it does not dereference any argument slots
1893 we already clobbered by tail call arguments (as noted in stored_args_map
1894 bitmap).
1895 Return nonzero if X expression dereferences such argument slots,
1896 zero otherwise. */
1898 static int
1900 {
1901 RTX_CODE code;
1912 {
1917 current_function_internal_arg_pointer
1920 else
1923 #ifdef ARGS_GROW_DOWNWARD
1925 #endif
1933 }
1935 /* Scan all subexpressions. */
1938 {
1940 {
1943 }
1945 {
1949 }
1950 }
1952 }
1954 /* Scan sequence after INSN if it does not dereference any argument slots
1955 we already clobbered by tail call arguments (as noted in stored_args_map
1956 bitmap). If MARK_STORED_ARGS_MAP, add stack slots for ARG to
1957 stored_args_map bitmap afterwards (when ARG is a register MARK_STORED_ARGS_MAP
1958 should be 0). Return nonzero if sequence after INSN dereferences such argument
1959 slots, zero otherwise. */
1961 static int
1963 {
1968 else
1977 {
1978 #ifdef ARGS_GROW_DOWNWARD
1980 #else
1982 #endif
1986 }
1988 }
1990 static tree
1992 {
1994 {
2003 {
2009 }
2014 }
2016 }
2019 /* If function value *VALUE was returned at the most significant end of a
2020 register, shift it towards the least significant end and convert it to
2021 TYPE's mode. Return true and update *VALUE if some action was needed.
2023 TYPE is the type of the function's return value, which is known not
2024 to have mode BLKmode. */
2026 static bool
2028 {
2030 {
2031 HOST_WIDE_INT shift;
2036 {
2041 }
2042 }
2044 }
2046 /* Generate all the code for a function call
2047 and return an rtx for its value.
2048 Store the value in TARGET (specified as an rtx) if convenient.
2049 If the value is stored in TARGET then TARGET is returned.
2050 If IGNORE is nonzero, then we ignore the value of the function call. */
2052 rtx
2054 {
2055 /* Nonzero if we are currently expanding a call. */
2058 /* List of actual parameters. */
2060 /* RTX for the function to be called. */
2061 rtx funexp;
2062 /* Sequence of insns to perform a tail recursive "call". */
2064 /* Sequence of insns to perform a normal "call". */
2066 /* Sequence of insns to perform a tail recursive "call". */
2068 /* Data type of the function. */
2069 tree funtype;
2070 tree type_arg_types;
2071 /* Declaration of the function being called,
2072 or 0 if the function is computed (not known by name). */
2074 /* The type of the function being called. */
2075 tree fntype;
2076 rtx insn;
2081 /* Register in which non-BLKmode value will be returned,
2082 or 0 if no value or if value is BLKmode. */
2083 rtx valreg;
2084 /* Address where we should return a BLKmode value;
2085 0 if value not BLKmode. */
2087 /* Nonzero if that address is being passed by treating it as
2088 an extra, implicit first parameter. Otherwise,
2089 it is passed by being copied directly into struct_value_rtx. */
2091 /* Size of aggregate value wanted, or zero if none wanted
2092 or if we are using the non-reentrant PCC calling convention
2093 or expecting the value in registers. */
2095 /* Nonzero if called function returns an aggregate in memory PCC style,
2096 by returning the address of where to find it. */
2100 /* Number of actual parameters in this call, including struct value addr. */
2102 /* Number of named args. Args after this are anonymous ones
2103 and they must all go on the stack. */
2106 /* Vector of information about each argument.
2107 Arguments are numbered in the order they will be pushed,
2108 not the order they are written. */
2111 /* Total size in bytes of all the stack-parms scanned so far. */
2114 /* Size of arguments before any adjustments (such as rounding). */
2116 /* Data on reg parms scanned so far. */
2117 CUMULATIVE_ARGS args_so_far;
2118 /* Nonzero if a reg parm has been scanned. */
2120 /* Nonzero if this is an indirect function call. */
2122 /* Nonzero if we must avoid push-insns in the args for this call.
2123 If stack space is allocated for register parameters, but not by the
2124 caller, then it is preallocated in the fixed part of the stack frame.
2125 So the entire argument block must then be preallocated (i.e., we
2126 ignore PUSH_ROUNDING in that case). */
2130 /* Size of the stack reserved for parameter registers. */
2133 /* Address of space preallocated for stack parms
2134 (on machines that lack push insns), or 0 if space not preallocated. */
2137 /* Mask of ECF_ flags. */
2139 /* Nonzero if this is a call to an inline function. */
2141 #ifdef REG_PARM_STACK_SPACE
2142 /* Define the boundary of the register parm stack space that needs to be
2143 saved, if any. */
2146 #endif
2154 /* State variables to track stack modifications. */
2160 /* Some stack pointer alterations we make are performed via
2161 allocate_dynamic_stack_space. This modifies the stack_pointer_delta,
2162 which we then also need to save/restore along the way. */
2165 rtx call_fusage;
2169 /* The alignment of the stack, in bits. */
2170 HOST_WIDE_INT preferred_stack_boundary;
2171 /* The alignment of the stack, in bytes. */
2172 HOST_WIDE_INT preferred_unit_stack_boundary;
2174 /* See if this is "nothrow" function call. */
2178 /* See if we can find a DECL-node for the actual function.
2179 As a result, decide whether this is a call to an integrable function. */
2183 {
2192 {
2193 /* In case this function later becomes inlinable,
2194 record that there was already a non-inline call to it.
2196 Use abstraction instead of setting TREE_ADDRESSABLE
2197 directly. */
2200 {
2203 }
2205 }
2214 }
2216 /* If we don't have specific function to call, see if we have a
2217 attributes set in the type. */
2218 else
2219 {
2226 }
2230 /* Warn if this value is an aggregate type,
2231 regardless of which calling convention we are using for it. */
2235 /* If the result of a pure or const function call is ignored (or void),
2236 and none of its arguments are volatile, we can avoid expanding the
2237 call and just evaluate the arguments for side-effects. */
2241 {
2243 tree arg;
2247 {
2250 }
2253 {
2258 }
2259 }
2261 #ifdef REG_PARM_STACK_SPACE
2263 #endif
2265 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2268 #endif
2270 /* Set up a place to return a structure. */
2272 /* Cater to broken compilers. */
2274 {
2275 /* This call returns a big structure. */
2278 #ifdef PCC_STATIC_STRUCT_RETURN
2279 {
2281 /* Easier than making that case work right. */
2283 {
2284 /* In case this is a static function, note that it has been
2285 used. */
2289 }
2290 }
2292 {
2296 {
2297 /* The structure value address arg is already in actparms.
2298 Pull it out. It might be nice to just leave it there, but
2299 we need to set structure_value_addr. */
2304 }
2307 else
2308 {
2309 /* For variable-sized objects, we must be called with a target
2310 specified. If we were to allocate space on the stack here,
2311 we would have no way of knowing when to free it. */
2317 }
2318 }
2320 }
2322 /* If called function is inline, try to integrate it. */
2325 {
2328 structure_value_addr);
2331 }
2333 /* Figure out the amount to which the stack should be aligned. */
2336 {
2340 }
2342 /* Operand 0 is a pointer-to-function; get the type of the function. */
2348 /* Munge the tree to split complex arguments into their imaginary
2349 and real parts. */
2351 {
2354 }
2355 else
2358 /* See if this is a call to a function that can return more than once
2359 or a call to longjmp or malloc. */
2365 /* If struct_value_rtx is 0, it means pass the address
2366 as if it were an extra parameter. */
2368 {
2369 /* If structure_value_addr is a REG other than
2370 virtual_outgoing_args_rtx, we can use always use it. If it
2371 is not a REG, we must always copy it into a register.
2372 If it is virtual_outgoing_args_rtx, we must copy it to another
2373 register in some cases. */
2375 || (ACCUMULATE_OUTGOING_ARGS
2376 && stack_arg_under_construction
2382 actparms
2385 temp),
2386 actparms);
2388 }
2390 /* Count the arguments and set NUM_ACTUALS. */
2392 num_actuals++;
2394 /* Compute number of named args.
2395 Normally, don't include the last named arg if anonymous args follow.
2396 We do include the last named arg if
2397 targetm.calls.strict_argument_naming() returns nonzero.
2398 (If no anonymous args follow, the result of list_length is actually
2399 one too large. This is harmless.)
2401 If targetm.calls.pretend_outgoing_varargs_named() returns
2402 nonzero, and targetm.calls.strict_argument_naming() returns zero,
2403 this machine will be able to place unnamed args that were passed
2404 in registers into the stack. So treat all args as named. This
2405 allows the insns emitting for a specific argument list to be
2406 independent of the function declaration.
2408 If targetm.calls.pretend_outgoing_varargs_named() returns zero,
2409 we do not have any reliable way to pass unnamed args in
2410 registers, so we must force them into memory. */
2415 n_named_args
2417 /* Don't include the last named arg. */
2419 /* Count the struct value address, if it is passed as a parm. */
2421 else
2422 /* If we know nothing, treat all args as named. */
2425 /* Start updating where the next arg would go.
2427 On some machines (such as the PA) indirect calls have a different
2428 calling convention than normal calls. The fourth argument in
2429 INIT_CUMULATIVE_ARGS tells the backend if this is an indirect call
2430 or not. */
2433 /* Make a vector to hold all the information about each arg. */
2437 /* Build up entries in the ARGS array, compute the size of the
2438 arguments into ARGS_SIZE, etc. */
2447 {
2448 /* If this function requires a variable-sized argument list, don't
2449 try to make a cse'able block for this call. We may be able to
2450 do this eventually, but it is too complicated to keep track of
2451 what insns go in the cse'able block and which don't. */
2455 }
2457 /* Now make final decision about preallocating stack space. */
2462 /* If the structure value address will reference the stack pointer, we
2463 must stabilize it. We don't need to do this if we know that we are
2464 not going to adjust the stack pointer in processing this call. */
2469 structure_value_addr))
2474 /* Tail calls can make things harder to debug, and we're traditionally
2475 pushed these optimizations into -O2. Don't try if we're already
2476 expanding a call, as that means we're an argument. Don't try if
2477 there's cleanups, as we know there's code to follow the call.
2479 If rtx_equal_function_value_matters is false, that means we've
2480 finished with regular parsing. Which means that some of the
2481 machinery we use to generate tail-calls is no longer in place.
2482 This is most often true of sjlj-exceptions, which we couldn't
2483 tail-call to anyway.
2485 If current_nesting_level () == 0, we're being called after
2486 the function body has been expanded. This can happen when
2487 setting up trampolines in expand_function_end. */
2489 || !flag_optimize_sibling_calls
2490 || !rtx_equal_function_value_matters
2496 /* Tail recursion fails, when we are not dealing with recursive calls. */
2502 /* Rest of purposes for tail call optimizations to fail. */
2504 #ifdef HAVE_sibcall_epilogue
2505 !HAVE_sibcall_epilogue
2506 #else
2507 1
2508 #endif
2509 || !try_tail_call
2510 /* Doing sibling call optimization needs some work, since
2511 structure_value_addr can be allocated on the stack.
2512 It does not seem worth the effort since few optimizable
2513 sibling calls will return a structure. */
2515 /* Check whether the target is able to optimize the call
2516 into a sibcall. */
2518 /* Functions that do not return exactly once may not be sibcall
2519 optimized. */
2522 /* If the called function is nested in the current one, it might access
2523 some of the caller's arguments, but could clobber them beforehand if
2524 the argument areas are shared. */
2526 /* If this function requires more stack slots than the current
2527 function, we cannot change it into a sibling call. */
2529 /* If the callee pops its own arguments, then it must pop exactly
2530 the same number of arguments as the current function. */
2534 current_function_args_size))
2539 {
2542 /* Ok, we're going to give the tail call the old college try.
2543 This means we're going to evaluate the function arguments
2544 up to three times. There are two degrees of badness we can
2545 encounter, those that can be unsaved and those that can't.
2546 (See unsafe_for_reeval commentary for details.)
2548 Generate a new argument list. Pass safe arguments through
2549 unchanged. For the easy badness wrap them in UNSAVE_EXPRs.
2550 For hard badness, evaluate them now and put their resulting
2551 rtx in a temporary VAR_DECL.
2553 initialize_argument_information has ordered the array for the
2554 order to be pushed, and we must remember this when reconstructing
2555 the original argument order. */
2558 {
2562 }
2563 else
2564 {
2568 }
2571 {
2573 /* We need to build actparms for optimize_tail_recursion. We can
2574 safely trash away TREE_PURPOSE, since it is unused by this
2575 function. */
2578 }
2579 /* Do the same for the function address if it is an expression. */
2582 /* Expanding one of those dangerous arguments could have added
2583 cleanups, but otherwise give it a whirl. */
2586 }
2588 /* Generate a tail recursion sequence when calling ourselves. */
2591 {
2592 /* We want to emit any pending stack adjustments before the tail
2593 recursion "call". That way we know any adjustment after the tail
2594 recursion call can be ignored if we indeed use the tail recursion
2595 call expansion. */
2599 /* Emit any queued insns now; otherwise they would end up in
2600 only one of the alternates. */
2603 /* Use a new sequence to hold any RTL we generate. We do not even
2604 know if we will use this RTL yet. The final decision can not be
2605 made until after RTL generation for the entire function is
2606 complete. */
2608 /* If expanding any of the arguments creates cleanups, we can't
2609 do a tailcall. So, we'll need to pop the pending cleanups
2610 list. If, however, all goes well, and there are no cleanups
2611 then the call to expand_start_target_temps will have no
2612 effect. */
2615 {
2618 else
2620 }
2624 /* Restore the original pending stack adjustment for the sibling and
2625 normal call cases below. */
2628 }
2631 {
2632 /* A fork duplicates the profile information, and an exec discards
2633 it. We can't rely on fork/exec to be paired. So write out the
2634 profile information we have gathered so far, and clear it. */
2635 /* ??? When Linux's __clone is called with CLONE_VM set, profiling
2636 is subject to race conditions, just as with multithreaded
2637 programs. */
2640 }
2642 /* Ensure current function's preferred stack boundary is at least
2643 what we need. We don't have to increase alignment for recursive
2644 functions. */
2653 function_call_count++;
2655 /* We want to make two insn chains; one for a sibling call, the other
2656 for a normal call. We will select one of the two chains after
2657 initial RTL generation is complete. */
2659 {
2661 /* We want to emit any pending stack adjustments before the tail
2662 recursion "call". That way we know any adjustment after the tail
2663 recursion call can be ignored if we indeed use the tail recursion
2664 call expansion. */
2667 rtx insns;
2671 {
2672 /* Emit any queued insns now; otherwise they would end up in
2673 only one of the alternates. */
2676 /* State variables we need to save and restore between
2677 iterations. */
2680 }
2683 else
2686 /* Other state variables that we must reinitialize each time
2687 through the loop (that are not initialized by the loop itself). */
2691 /* Start a new sequence for the normal call case.
2693 From this point on, if the sibling call fails, we want to set
2694 sibcall_failure instead of continuing the loop. */
2698 {
2699 /* We know at this point that there are not currently any
2700 pending cleanups. If, however, in the process of evaluating
2701 the arguments we were to create some, we'll need to be
2702 able to get rid of them. */
2704 }
2706 /* Don't let pending stack adjusts add up to too much.
2707 Also, do all pending adjustments now if there is any chance
2708 this might be a call to alloca or if we are expanding a sibling
2709 call sequence or if we are calling a function that is to return
2710 with stack pointer depressed. */
2717 /* When calling a const function, we must pop the stack args right away,
2718 so that the pop is deleted or moved with the call. */
2720 NO_DEFER_POP;
2722 /* Precompute any arguments as needed. */
2726 /* Now we are about to start emitting insns that can be deleted
2727 if a libcall is deleted. */
2732 /* Compute the actual size of the argument block required. The variable
2733 and constant sizes must be combined, the size may have to be rounded,
2734 and there may be a minimum required size. When generating a sibcall
2735 pattern, do not round up, since we'll be re-using whatever space our
2736 caller provided. */
2737 unadjusted_args_size
2745 /* The argument block when performing a sibling call is the
2746 incoming argument block. */
2748 {
2750 argblock
2751 #ifdef STACK_GROWS_DOWNWARD
2753 #else
2755 #endif
2758 }
2760 /* If we have no actual push instructions, or shouldn't use them,
2761 make space for all args right now. */
2763 {
2765 {
2770 /* stack_arg_under_construction says whether a stack arg is
2771 being constructed at the old stack level. Pushing the stack
2772 gets a clean outgoing argument block. */
2775 }
2777 }
2778 else
2779 {
2780 /* Note that we must go through the motions of allocating an argument
2781 block even if the size is zero because we may be storing args
2782 in the area reserved for register arguments, which may be part of
2783 the stack frame. */
2787 /* Store the maximum argument space used. It will be pushed by
2788 the prologue (if ACCUMULATE_OUTGOING_ARGS, or stack overflow
2789 checking). */
2795 {
2797 {
2798 /* Since the stack pointer will never be pushed, it is
2799 possible for the evaluation of a parm to clobber
2800 something we have already written to the stack.
2801 Since most function calls on RISC machines do not use
2802 the stack, this is uncommon, but must work correctly.
2804 Therefore, we save any area of the stack that was already
2805 written and that we are using. Here we set up to do this
2806 by making a new stack usage map from the old one. The
2807 actual save will be done by store_one_arg.
2809 Another approach might be to try to reorder the argument
2810 evaluations to avoid this conflicting stack usage. */
2812 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2813 /* Since we will be writing into the entire argument area,
2814 the map must be allocated for its entire size, not just
2815 the part that is the responsibility of the caller. */
2817 #endif
2819 #ifdef ARGS_GROW_DOWNWARD
2822 #else
2824 needed);
2825 #endif
2830 initial_highest_arg_in_use);
2834 (highest_outgoing_arg_in_use
2838 /* The address of the outgoing argument list must not be
2839 copied to a register here, because argblock would be left
2840 pointing to the wrong place after the call to
2841 allocate_dynamic_stack_space below. */
2844 }
2845 else
2846 {
2848 {
2849 /* Try to reuse some or all of the pending_stack_adjust
2850 to get this space. */
2851 needed
2852 = (combine_pending_stack_adjustment_and_call
2855 preferred_unit_stack_boundary));
2857 /* combine_pending_stack_adjustment_and_call computes
2858 an adjustment before the arguments are allocated.
2859 Account for them and see whether or not the stack
2860 needs to go up or down. */
2864 {
2865 /* We're releasing stack space. */
2866 /* ??? We can avoid any adjustment at all if we're
2867 already aligned. FIXME. */
2871 }
2872 else
2873 /* We need to allocate space. We'll do that in
2874 push_block below. */
2876 }
2878 /* Special case this because overhead of `push_block' in
2879 this case is non-trivial. */
2882 else
2883 {
2885 #ifdef ARGS_GROW_DOWNWARD
2887 #endif
2888 }
2890 /* We only really need to call `copy_to_reg' in the case
2891 where push insns are going to be used to pass ARGBLOCK
2892 to a function call in ARGS. In that case, the stack
2893 pointer changes value from the allocation point to the
2894 call point, and hence the value of
2895 VIRTUAL_OUTGOING_ARGS_RTX changes as well. But might
2896 as well always do it. */
2898 }
2899 }
2900 }
2903 {
2904 /* The save/restore code in store_one_arg handles all
2905 cases except one: a constructor call (including a C
2906 function returning a BLKmode struct) to initialize
2907 an argument. */
2909 {
2910 #ifndef OUTGOING_REG_PARM_STACK_SPACE
2913 #else
2915 #endif
2917 {
2919 NULL_RTX);
2923 /* stack_arg_under_construction says whether a stack
2924 arg is being constructed at the old stack level.
2925 Pushing the stack gets a clean outgoing argument
2926 block. */
2927 old_stack_arg_under_construction
2930 /* Make a new map for the new argument list. */
2934 }
2936 BITS_PER_UNIT);
2937 }
2939 /* If argument evaluation might modify the stack pointer,
2940 copy the address of the argument list to a register. */
2943 {
2946 }
2947 }
2951 /* If we push args individually in reverse order, perform stack alignment
2952 before the first push (the last arg). */
2955 {
2956 /* When the stack adjustment is pending, we get better code
2957 by combining the adjustments. */
2961 {
2962 pending_stack_adjust
2963 = (combine_pending_stack_adjustment_and_call
2966 preferred_unit_stack_boundary));
2968 }
2972 }
2973 /* Now that the stack is properly aligned, pops can't safely
2974 be deferred during the evaluation of the arguments. */
2975 NO_DEFER_POP;
2979 /* Figure out the register where the value, if any, will come back. */
2983 {
2987 else
2989 }
2991 /* Precompute all register parameters. It isn't safe to compute anything
2992 once we have started filling any specific hard regs. */
2995 #ifdef REG_PARM_STACK_SPACE
2996 /* Save the fixed argument area if it's part of the caller's frame and
2997 is clobbered by argument setup for this call. */
3001 #endif
3003 /* Now store (and compute if necessary) all non-register parms.
3004 These come before register parms, since they can require block-moves,
3005 which could clobber the registers used for register parms.
3006 Parms which have partial registers are not stored here,
3007 but we do preallocate space here if they want that. */
3011 {
3016 reg_parm_stack_space)
3028 call_fusage);
3029 }
3031 /* If we have a parm that is passed in registers but not in memory
3032 and whose alignment does not permit a direct copy into registers,
3033 make a group of pseudos that correspond to each register that we
3034 will later fill. */
3038 /* Now store any partially-in-registers parm.
3039 This is the last place a block-move can happen. */
3043 {
3048 reg_parm_stack_space)
3053 }
3055 /* If we pushed args in forward order, perform stack alignment
3056 after pushing the last arg. */
3061 /* If register arguments require space on the stack and stack space
3062 was not preallocated, allocate stack space here for arguments
3063 passed in registers. */
3064 #ifdef OUTGOING_REG_PARM_STACK_SPACE
3068 #endif
3070 /* Pass the function the address in which to return a
3071 structure value. */
3073 {
3074 structure_value_addr
3079 NULL_RTX)));
3083 }
3091 /* Perform postincrements before actually calling the function. */
3094 /* Save a pointer to the last insn before the call, so that we can
3095 later safely search backwards to find the CALL_INSN. */
3098 /* Set up next argument register. For sibling calls on machines
3099 with register windows this should be the incoming register. */
3100 #ifdef FUNCTION_INCOMING_ARG
3104 else
3105 #endif
3109 /* All arguments and registers used for the call must be set up by
3110 now! */
3112 /* Stack must be properly aligned now. */
3116 /* Generate the actual call instruction. */
3122 /* If call is cse'able, make appropriate pair of reg-notes around it.
3123 Test valreg so we don't crash; may safely ignore `const'
3124 if return type is void. Disable for PARALLEL return values, because
3125 we have no way to move such values into a pseudo register. */
3127 {
3128 rtx insns;
3129 rtx insn;
3134 /* Expansion of block moves possibly introduced a loop that may
3135 not appear inside libcall block. */
3141 {
3144 }
3145 else
3146 {
3150 /* Mark the return value as a pointer if needed. */
3157 && fndecl
3165 else
3166 {
3167 /* Construct an "equal form" for the value which
3168 mentions all the arguments in order as well as
3169 the function name. */
3180 note);
3181 }
3185 }
3186 }
3188 {
3192 /* The return value from a malloc-like function is a pointer. */
3198 /* The return value from a malloc-like function can not alias
3199 anything else. */
3204 /* Write out the sequence. */
3209 }
3211 /* For calls to `setjmp', etc., inform flow.c it should complain
3212 if nonvolatile values are live. For functions that cannot return,
3213 inform flow that control does not fall through. */
3216 {
3217 /* The barrier must be emitted
3218 immediately after the CALL_INSN. Some ports emit more
3219 than just a CALL_INSN above, so we must search for it here. */
3223 {
3225 /* There was no CALL_INSN? */
3228 }
3232 /* Stack adjustments after a noreturn call are dead code.
3233 However when NO_DEFER_POP is in effect, we must preserve
3234 stack_pointer_delta. */
3236 {
3239 }
3240 }
3245 /* If value type not void, return an rtx for the value. */
3247 /* If there are cleanups to be called, don't use a hard reg as target.
3248 We need to double check this and see if it matters anymore. */
3250 {
3255 }
3261 {
3263 {
3264 target
3267 structure_value_addr));
3269 }
3270 }
3272 {
3273 /* This is the special C++ case where we need to
3274 know what the true target was. We take care to
3275 never use this value more than once in one expression. */
3279 }
3280 /* Handle calls that return values in multiple non-contiguous locations.
3281 The Irix 6 ABI has examples of this. */
3283 {
3284 /* Second condition is added because "target" is freed at the
3285 the end of "pass0" for -O2 when call is made to
3286 expand_end_target_temps (). Its "in_use" flag has been set
3287 to false, so allocate a new temp. */
3289 {
3290 /* This will only be assigned once, so it can be readonly. */
3298 }
3304 /* We can not support sibling calls for this case. */
3306 }
3310 {
3311 /* TARGET and VALREG cannot be equal at this point because the
3312 latter would not have REG_FUNCTION_VALUE_P true, while the
3313 former would if it were referring to the same register.
3315 If they refer to the same register, this move will be a no-op,
3316 except when function inlining is being done. */
3319 /* If we are setting a MEM, this code must be executed. Since it is
3320 emitted after the call insn, sibcall optimization cannot be
3321 performed in that case. */
3324 }
3326 {
3329 /* We can not support sibling calls for this case. */
3331 }
3332 else
3333 {
3338 }
3341 {
3342 /* If we promoted this return value, make the proper SUBREG. TARGET
3343 might be const0_rtx here, so be careful. */
3347 {
3352 /* If we don't promote as expected, something is wrong. */
3360 {
3367 }
3371 }
3372 }
3374 /* If size of args is variable or this was a constructor call for a stack
3375 argument, restore saved stack-pointer value. */
3378 {
3386 }
3388 {
3389 #ifdef REG_PARM_STACK_SPACE
3393 #endif
3395 /* If we saved any argument areas, restore them. */
3398 {
3400 rtx stack_area
3407 else
3410 BLOCK_OP_CALL_PARM);
3411 }
3415 }
3417 /* If this was alloca, record the new stack level for nonlocal gotos.
3418 Check for the handler slots since we might not have a save area
3419 for non-local gotos. */
3424 /* Free up storage we no longer need. */
3430 {
3431 /* Undo the fake expand_start_target_temps we did earlier. If
3432 there had been any cleanups created, we've already set
3433 sibcall_failure. */
3435 }
3437 /* If this function is returning into a memory location marked as
3438 readonly, it means it is initializing that location. We normally treat
3439 functions as not clobbering such locations, so we need to specify that
3440 this one does. We do this by adding the appropriate CLOBBER to the
3441 CALL_INSN function usage list. This cannot be done by emitting a
3442 standalone CLOBBER after the call because the latter would be ignored
3443 by at least the delay slot scheduling pass. We do this now instead of
3444 adding to call_fusage before the call to emit_call_1 because TARGET
3445 may be modified in the meantime. */
3448 add_function_usage_to
3451 NULL_RTX));
3457 {
3460 /* Restore the pending stack adjustment now that we have
3461 finished generating the sibling call sequence. */
3466 /* Prepare arg structure for next iteration. */
3468 {
3472 }
3475 }
3476 else
3477 {
3480 /* Verify that we've deallocated all the stack we used. */
3485 }
3487 /* If something prevents making this a sibling call,
3488 zero out the sequence. */
3491 }
3493 /* The function optimize_sibling_and_tail_recursive_calls doesn't
3494 handle CALL_PLACEHOLDERs inside other CALL_PLACEHOLDERs. This
3495 can happen if the arguments to this function call an inline
3496 function who's expansion contains another CALL_PLACEHOLDER.
3498 If there are any C_Ps in any of these sequences, replace them
3499 with their normal call. */
3516 /* If this was a potential tail recursion site, then emit a
3517 CALL_PLACEHOLDER with the normal and the tail recursion streams.
3518 One of them will be selected later. */
3520 {
3521 /* The tail recursion label must be kept around. We could expose
3522 its use in the CALL_PLACEHOLDER, but that creates unwanted edges
3523 and makes determining true tail recursion sites difficult.
3525 So we set LABEL_PRESERVE_P here, then clear it when we select
3526 one of the call sequences after rtl generation is complete. */
3530 tail_call_insns,
3531 tail_recursion_insns,
3532 tail_recursion_label));
3533 }
3534 else
3537 currently_expanding_call--;
3539 /* If this function returns with the stack pointer depressed, ensure
3540 this block saves and restores the stack pointer, show it was
3541 changed, and adjust for any outgoing arg space. */
3543 {
3548 }
3551 }
3553 /* Traverse an argument list in VALUES and expand all complex
3554 arguments into their components. */
3555 tree
3557 {
3558 tree p;
3560 /* Before allocating memory, check for the common case of no complex. */
3562 {
3567 }
3570 found:
3574 {
3576 tree complex_type;
3584 {
3585 tree subtype;
3599 /* Skip the newly created node. */
3601 }
3602 }
3605 }
3607 /* Traverse a list of TYPES and expand all complex types into their
3608 components. */
3609 tree
3611 {
3612 tree p;
3614 /* Before allocating memory, check for the common case of no complex. */
3616 {
3621 }
3624 found:
3628 {
3633 {
3636 /* Rewrite complex type with component type. */
3640 /* Add another component type for the imaginary part. */
3645 /* Skip the newly created node. */
3647 }
3648 }
3651 }
3652 \f
3653 /* Output a library call to function FUN (a SYMBOL_REF rtx).
3654 The RETVAL parameter specifies whether return value needs to be saved, other
3655 parameters are documented in the emit_library_call function below. */
3657 static rtx
3661 {
3662 /* Total size in bytes of all the stack-parms scanned so far. */
3664 /* Size of arguments before any adjustments (such as rounding). */
3667 rtx fun;
3671 CUMULATIVE_ARGS args_so_far;
3672 struct arg
3673 {
3674 rtx value;
3676 rtx reg;
3679 rtx save_area;
3680 };
3685 rtx valreg;
3691 rtx before_call;
3694 #ifdef REG_PARM_STACK_SPACE
3695 /* Define the boundary of the register parm stack space that needs to be
3696 save, if any. */
3699 #endif
3701 /* Size of the stack reserved for parameter registers. */
3707 #ifdef REG_PARM_STACK_SPACE
3709 #endif
3711 /* By default, library functions can not throw. */
3715 {
3742 }
3745 /* Ensure current function's preferred stack boundary is at least
3746 what we need. */
3750 /* If this kind of value comes back in memory,
3751 decide where in memory it should come back. */
3753 {
3756 {
3757 #ifdef PCC_STATIC_STRUCT_RETURN
3758 rtx pointer_reg
3768 else
3770 #endif
3771 /* This call returns a big structure. */
3773 }
3774 }
3775 else
3778 /* ??? Unfinished: must pass the memory address as an argument. */
3780 /* Copy all the libcall-arguments out of the varargs data
3781 and into a vector ARGVEC.
3783 Compute how to pass each argument. We only support a very small subset
3784 of the full argument passing conventions to limit complexity here since
3785 library functions shouldn't have many args. */
3790 #ifdef INIT_CUMULATIVE_LIBCALL_ARGS
3792 #else
3794 #endif
3801 /* Now we are about to start emitting insns that can be deleted
3802 if a libcall is deleted. */
3808 /* If there's a structure value address to be passed,
3809 either pass it in the special place, or pass it as an extra argument. */
3811 {
3813 nargs++;
3815 /* Make sure it is a reasonable operand for a move or push insn. */
3825 #ifdef FUNCTION_ARG_PARTIAL_NREGS
3828 #endif
3831 #ifdef STACK_PARMS_IN_REG_PARM_AREA
3833 #else
3835 #endif
3844 count++;
3845 }
3848 {
3852 /* We cannot convert the arg value to the mode the library wants here;
3853 must do it earlier where we know the signedness of the arg. */
3858 /* There's no need to call protect_from_queue, because
3859 either emit_move_insn or emit_push_insn will do that. */
3861 /* Make sure it is a reasonable operand for a move or push insn. */
3866 #ifdef FUNCTION_ARG_PASS_BY_REFERENCE
3868 {
3869 rtx slot;
3871 #ifdef FUNCTION_ARG_CALLEE_COPIES
3874 #endif
3875 ;
3877 /* loop.c won't look at CALL_INSN_FUNCTION_USAGE of const/pure
3878 functions, so we have to pretend this isn't such a function. */
3880 {
3884 }
3887 /* If this was a CONST function, it is now PURE since
3888 it now reads memory. */
3890 {
3893 }
3898 {
3902 }
3903 else
3904 {
3907 slot
3913 }
3917 call_fusage);
3921 slot),
3922 call_fusage);
3926 }
3927 #endif
3934 #ifdef FUNCTION_ARG_PARTIAL_NREGS
3937 #else
3939 #endif
3942 #ifdef STACK_PARMS_IN_REG_PARM_AREA
3944 #else
3946 #endif
3958 }
3960 /* If this machine requires an external definition for library
3961 functions, write one out. */
3966 + stack_pointer_delta
3968 / STACK_BYTES
3973 reg_parm_stack_space);
3975 #ifndef OUTGOING_REG_PARM_STACK_SPACE
3977 #endif
3983 {
3984 /* Since the stack pointer will never be pushed, it is possible for
3985 the evaluation of a parm to clobber something we have already
3986 written to the stack. Since most function calls on RISC machines
3987 do not use the stack, this is uncommon, but must work correctly.
3989 Therefore, we save any area of the stack that was already written
3990 and that we are using. Here we set up to do this by making a new
3991 stack usage map from the old one.
3993 Another approach might be to try to reorder the argument
3994 evaluations to avoid this conflicting stack usage. */
3998 #ifndef OUTGOING_REG_PARM_STACK_SPACE
3999 /* Since we will be writing into the entire argument area, the
4000 map must be allocated for its entire size, not just the part that
4001 is the responsibility of the caller. */
4003 #endif
4005 #ifdef ARGS_GROW_DOWNWARD
4008 #else
4010 needed);
4011 #endif
4016 initial_highest_arg_in_use);
4023 /* We must be careful to use virtual regs before they're instantiated,
4024 and real regs afterwards. Loop optimization, for example, can create
4025 new libcalls after we've instantiated the virtual regs, and if we
4026 use virtuals anyway, they won't match the rtl patterns. */
4030 else
4032 }
4033 else
4034 {
4037 }
4039 /* If we push args individually in reverse order, perform stack alignment
4040 before the first push (the last arg). */
4046 {
4049 }
4050 else
4051 {
4054 }
4056 #ifdef REG_PARM_STACK_SPACE
4058 {
4059 /* The argument list is the property of the called routine and it
4060 may clobber it. If the fixed area has been used for previous
4061 parameters, we must save and restore it. */
4064 }
4065 #endif
4067 /* Push the args that need to be pushed. */
4069 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
4070 are to be pushed. */
4072 {
4080 {
4082 {
4083 /* If this is being stored into a pre-allocated, fixed-size,
4084 stack area, save any previous data at that location. */
4086 #ifdef ARGS_GROW_DOWNWARD
4087 /* stack_slot is negative, but we want to index stack_usage_map
4088 with positive values. */
4091 #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. */
4107 unsigned int size
4109 enum machine_mode save_mode
4111 rtx adr
4114 rtx stack_area
4118 {
4125 stack_area,
4127 BLOCK_OP_CALL_PARM);
4128 }
4129 else
4130 {
4134 }
4135 }
4136 }
4141 reg_parm_stack_space,
4144 /* Now mark the segment we just used. */
4149 NO_DEFER_POP;
4150 }
4151 }
4153 /* If we pushed args in forward order, perform stack alignment
4154 after pushing the last arg. */
4161 else
4166 /* Now load any reg parms into their regs. */
4168 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
4169 are to be pushed. */
4171 {
4176 /* Handle calls that pass values in multiple non-contiguous
4177 locations. The PA64 has examples of this for library calls. */
4183 NO_DEFER_POP;
4184 }
4186 /* Any regs containing parms remain in use through the call. */
4188 {
4194 }
4196 /* Pass the function the address in which to return a structure value. */
4198 {
4202 NULL_RTX)));
4205 }
4207 /* Don't allow popping to be deferred, since then
4208 cse'ing of library calls could delete a call and leave the pop. */
4209 NO_DEFER_POP;
4213 /* Stack must be properly aligned now. */
4219 /* We pass the old value of inhibit_defer_pop + 1 to emit_call_1, which
4220 will set inhibit_defer_pop to that value. */
4221 /* The return type is needed to decide how many bytes the function pops.
4222 Signedness plays no role in that, so for simplicity, we pretend it's
4223 always signed. We also assume that the list of arguments passed has
4224 no impact, so we pretend it is unknown. */
4230 struct_value_size,
4232 valreg,
4235 /* For calls to `setjmp', etc., inform flow.c it should complain
4236 if nonvolatile values are live. For functions that cannot return,
4237 inform flow that control does not fall through. */
4240 {
4241 /* The barrier note must be emitted
4242 immediately after the CALL_INSN. Some ports emit more than
4243 just a CALL_INSN above, so we must search for it here. */
4247 {
4249 /* There was no CALL_INSN? */
4252 }
4255 }
4257 /* Now restore inhibit_defer_pop to its actual original value. */
4258 OK_DEFER_POP;
4260 /* If call is cse'able, make appropriate pair of reg-notes around it.
4261 Test valreg so we don't crash; may safely ignore `const'
4262 if return type is void. Disable for PARALLEL return values, because
4263 we have no way to move such values into a pseudo register. */
4265 {
4266 rtx insns;
4269 {
4273 }
4274 else
4275 {
4277 rtx temp;
4281 {
4286 }
4290 /* Construct an "equal form" for the value which mentions all the
4291 arguments in order as well as the function name. */
4304 note);
4309 }
4310 }
4313 /* Copy the value to the right place. */
4315 {
4317 {
4322 }
4324 {
4328 }
4331 else
4333 }
4336 {
4337 #ifdef REG_PARM_STACK_SPACE
4341 #endif
4343 /* If we saved any argument areas, restore them. */
4346 {
4357 BLOCK_OP_CALL_PARM);
4358 else
4360 }
4364 }
4368 }
4369 \f
4370 /* Output a library call to function FUN (a SYMBOL_REF rtx)
4371 (emitting the queue unless NO_QUEUE is nonzero),
4372 for a value of mode OUTMODE,
4373 with NARGS different arguments, passed as alternating rtx values
4374 and machine_modes to convert them to.
4375 The rtx values should have been passed through protect_from_queue already.
4377 FN_TYPE should be LCT_NORMAL for `normal' calls, LCT_CONST for `const'
4378 calls, LCT_PURE for `pure' calls, LCT_CONST_MAKE_BLOCK for `const' calls
4379 which should be enclosed in REG_LIBCALL/REG_RETVAL notes,
4380 LCT_PURE_MAKE_BLOCK for `purep' calls which should be enclosed in
4381 REG_LIBCALL/REG_RETVAL notes with extra (use (memory (scratch)),
4382 or other LCT_ value for other types of library calls. */
4384 void
4387 {
4393 }
4394 \f
4395 /* Like emit_library_call except that an extra argument, VALUE,
4396 comes second and says where to store the result.
4397 (If VALUE is zero, this function chooses a convenient way
4398 to return the value.
4400 This function returns an rtx for where the value is to be found.
4401 If VALUE is nonzero, VALUE is returned. */
4403 rtx
4407 {
4408 rtx result;
4417 }
4418 \f
4419 /* Store a single argument for a function call
4420 into the register or memory area where it must be passed.
4421 *ARG describes the argument value and where to pass it.
4423 ARGBLOCK is the address of the stack-block for all the arguments,
4424 or 0 on a machine where arguments are pushed individually.
4426 MAY_BE_ALLOCA nonzero says this could be a call to `alloca'
4427 so must be careful about how the stack is used.
4429 VARIABLE_SIZE nonzero says that this was a variable-sized outgoing
4430 argument stack. This is used if ACCUMULATE_OUTGOING_ARGS to indicate
4431 that we need not worry about saving and restoring the stack.
4433 FNDECL is the declaration of the function we are calling.
4435 Return nonzero if this arg should cause sibcall failure,
4436 zero otherwise. */
4438 static int
4441 {
4452 /* Push a new temporary level for any temporaries we make for
4453 this argument. */
4457 {
4458 /* If this is being stored into a pre-allocated, fixed-size, stack area,
4459 save any previous data at that location. */
4461 {
4462 #ifdef ARGS_GROW_DOWNWARD
4463 /* stack_slot is negative, but we want to index stack_usage_map
4464 with positive values. */
4467 else
4471 #else
4474 else
4478 #endif
4481 /* Don't worry about things in the fixed argument area;
4482 it has already been saved. */
4486 i++;
4489 {
4490 /* We need to make a save area. */
4497 {
4506 BLOCK_OP_CALL_PARM);
4507 }
4508 else
4509 {
4512 }
4513 }
4514 }
4515 }
4517 /* If this isn't going to be placed on both the stack and in registers,
4518 set up the register and number of words. */
4520 {
4523 else
4526 }
4529 /* Being passed entirely in a register. We shouldn't be called in
4530 this case. */
4533 /* If this arg needs special alignment, don't load the registers
4534 here. */
4538 /* If this is being passed partially in a register, we can't evaluate
4539 it directly into its stack slot. Otherwise, we can. */
4541 {
4542 /* stack_arg_under_construction is nonzero if a function argument is
4543 being evaluated directly into the outgoing argument list and
4544 expand_call must take special action to preserve the argument list
4545 if it is called recursively.
4547 For scalar function arguments stack_usage_map is sufficient to
4548 determine which stack slots must be saved and restored. Scalar
4549 arguments in general have pass_on_stack == 0.
4551 If this argument is initialized by a function which takes the
4552 address of the argument (a C++ constructor or a C function
4553 returning a BLKmode structure), then stack_usage_map is
4554 insufficient and expand_call must push the stack around the
4555 function call. Such arguments have pass_on_stack == 1.
4557 Note that it is always safe to set stack_arg_under_construction,
4558 but this generates suboptimal code if set when not needed. */
4561 stack_arg_under_construction++;
4564 (partial
4569 /* If we are promoting object (or for any other reason) the mode
4570 doesn't agree, convert the mode. */
4577 stack_arg_under_construction--;
4578 }
4580 /* Don't allow anything left on stack from computation
4581 of argument to alloca. */
4586 /* If the value is already in the stack slot, we are done. */
4587 ;
4589 {
4592 /* Argument is a scalar, not entirely passed in registers.
4593 (If part is passed in registers, arg->partial says how much
4594 and emit_push_insn will take care of putting it there.)
4596 Push it, and if its size is less than the
4597 amount of space allocated to it,
4598 also bump stack pointer by the additional space.
4599 Note that in C the default argument promotions
4600 will prevent such mismatches. */
4603 /* Compute how much space the push instruction will push.
4604 On many machines, pushing a byte will advance the stack
4605 pointer by a halfword. */
4606 #ifdef PUSH_ROUNDING
4608 #endif
4611 /* Compute how much space the argument should get:
4612 round up to a multiple of the alignment for arguments. */
4618 /* This isn't already where we want it on the stack, so put it there.
4619 This can either be done with push or copy insns. */
4625 /* Unless this is a partially-in-register argument, the argument is now
4626 in the stack. */
4629 }
4630 else
4631 {
4632 /* BLKmode, at least partly to be pushed. */
4636 rtx size_rtx;
4638 /* Pushing a nonscalar.
4639 If part is passed in registers, PARTIAL says how much
4640 and emit_push_insn will take care of putting it there. */
4642 /* Round its size up to a multiple
4643 of the allocation unit for arguments. */
4646 {
4649 }
4650 else
4651 {
4652 /* PUSH_ROUNDING has no effect on us, because
4653 emit_push_insn for BLKmode is careful to avoid it. */
4655 {
4656 /* Use the size of the elt to compute excess. */
4661 }
4662 else
4668 }
4670 /* Some types will require stricter alignment, which will be
4671 provided for elsewhere in argument layout. */
4674 /* When an argument is padded down, the block is aligned to
4675 PARM_BOUNDARY, but the actual argument isn't. */
4677 {
4681 {
4684 }
4685 }
4688 {
4689 /* emit_push_insn might not work properly if arg->value and
4690 argblock + arg->locate.offset areas overlap. */
4697 current_function_internal_arg_pointer
4699 {
4703 /* expand_call should ensure this. */
4708 {
4711 }
4713 {
4716 }
4717 }
4718 }
4725 /* Unless this is a partially-in-register argument, the argument is now
4726 in the stack.
4728 ??? Unlike the case above, in which we want the actual
4729 address of the data, so that we can load it directly into a
4730 register, here we want the address of the stack slot, so that
4731 it's properly aligned for word-by-word copying or something
4732 like that. It's not clear that this is always correct. */
4735 }
4737 /* Mark all slots this store used. */
4743 /* Once we have pushed something, pops can't safely
4744 be deferred during the rest of the arguments. */
4745 NO_DEFER_POP;
4747 /* ANSI doesn't require a sequence point here,
4748 but PCC has one, so this will avoid some problems. */
4751 /* Free any temporary slots made in processing this argument. Show
4752 that we might have taken the address of something and pushed that
4753 as an operand. */
4759 }
4761 /* Nonzero if we do not know how to pass TYPE solely in registers.
4762 We cannot do so in the following cases:
4764 - if the type has variable size
4765 - if the type is marked as addressable (it is required to be constructed
4766 into the stack)
4767 - if the padding and mode of the type is such that a copy into a register
4768 would put it into the wrong part of the register.
4770 Which padding can't be supported depends on the byte endianness.
4772 A value in a register is implicitly padded at the most significant end.
4773 On a big-endian machine, that is the lower end in memory.
4774 So a value padded in memory at the upper end can't go in a register.
4775 For a little-endian machine, the reverse is true. */
4777 bool
4779 {
4783 /* If the type has variable size... */
4787 /* If the type is marked as addressable (it is required
4788 to be constructed into the stack)... */
4792 /* If the padding and mode of the type is such that a copy into
4793 a register would put it into the wrong part of the register. */
4801 }