| blob | 72cf9e016c80555a76ef84ef110a8292bdd31876 |
1 /* Convert function calls to rtl insns, for GNU C compiler.
2 Copyright (C) 1989-2017 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
9 version.
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
58 /* Like PREFERRED_STACK_BOUNDARY but in units of bytes, not bits. */
59 #define STACK_BYTES (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT)
61 /* Data structure and subroutines used within expand_call. */
63 struct arg_data
64 {
65 /* Tree node for this argument. */
66 tree tree_value;
67 /* Mode for value; TYPE_MODE unless promoted. */
68 machine_mode mode;
69 /* Current RTL value for argument, or 0 if it isn't precomputed. */
70 rtx value;
71 /* Initially-compute RTL value for argument; only for const functions. */
72 rtx initial_value;
73 /* Register to pass this argument in, 0 if passed on stack, or an
74 PARALLEL if the arg is to be copied into multiple non-contiguous
75 registers. */
76 rtx reg;
77 /* Register to pass this argument in when generating tail call sequence.
78 This is not the same register as for normal calls on machines with
79 register windows. */
80 rtx tail_call_reg;
81 /* If REG is a PARALLEL, this is a copy of VALUE pulled into the correct
82 form for emit_group_move. */
83 rtx parallel_value;
84 /* If value is passed in neither reg nor stack, this field holds a number
85 of a special slot to be used. */
86 rtx special_slot;
87 /* For pointer bounds hold an index of parm bounds are bound to. -1 if
88 there is no such pointer. */
90 /* If pointer_arg refers a structure, then pointer_offset holds an offset
91 of a pointer in this structure. */
93 /* If REG was promoted from the actual mode of the argument expression,
94 indicates whether the promotion is sign- or zero-extended. */
96 /* Number of bytes to put in registers. 0 means put the whole arg
97 in registers. Also 0 if not passed in registers. */
99 /* Nonzero if argument must be passed on stack.
100 Note that some arguments may be passed on the stack
101 even though pass_on_stack is zero, just because FUNCTION_ARG says so.
102 pass_on_stack identifies arguments that *cannot* go in registers. */
104 /* Some fields packaged up for locate_and_pad_parm. */
106 /* Location on the stack at which parameter should be stored. The store
107 has already been done if STACK == VALUE. */
108 rtx stack;
109 /* Location on the stack of the start of this argument slot. This can
110 differ from STACK if this arg pads downward. This location is known
111 to be aligned to TARGET_FUNCTION_ARG_BOUNDARY. */
112 rtx stack_slot;
113 /* Place that this stack area has been saved, if needed. */
114 rtx save_area;
115 /* If an argument's alignment does not permit direct copying into registers,
116 copy in smaller-sized pieces into pseudos. These are stored in a
117 block pointed to by this field. The next field says how many
118 word-sized pseudos we made. */
121 };
123 /* A vector of one char per byte of stack space. A byte if nonzero if
124 the corresponding stack location has been used.
125 This vector is used to prevent a function call within an argument from
126 clobbering any stack already set up. */
129 /* Size of STACK_USAGE_MAP. */
132 /* A bitmap of virtual-incoming stack space. Bit is set if the corresponding
133 stack location's tail call argument has been already stored into the stack.
134 This bitmap is used to prevent sibling call optimization if function tries
135 to use parent's incoming argument slots when they have been already
136 overwritten with tail call arguments. */
139 /* stack_arg_under_construction is nonzero when an argument may be
140 initialized with a constructor call (including a C function that
141 returns a BLKmode struct) and expand_call must take special action
142 to make sure the object being constructed does not overlap the
143 argument list for the constructor call. */
148 cumulative_args_t);
175 #ifdef REG_PARM_STACK_SPACE
178 #endif
179 \f
180 /* Force FUNEXP into a form suitable for the address of a CALL,
181 and return that as an rtx. Also load the static chain register
182 if FNDECL is a nested function.
184 CALL_FUSAGE points to a variable holding the prospective
185 CALL_INSN_FUNCTION_USAGE information. */
187 rtx
190 {
191 /* Make a valid memory address and copy constants through pseudo-regs,
192 but not for a constant address if -fno-function-cse. */
194 {
195 /* If it's an indirect call by descriptor, generate code to perform
196 runtime identification of the pointer and load the descriptor. */
198 {
203 fndecl_or_type
205 fndecl_or_type);
212 /* Avoid long live ranges around function calls. */
218 /* Emit the runtime identification pattern. */
221 call_lab);
223 /* Statically predict the branch to very likely taken. */
228 /* Load the descriptor. */
237 POINTER_SIZE / BITS_PER_UNIT
246 {
249 }
251 /* Make sure we're not going to be overwritten below. */
253 }
255 /* If we are using registers for parameters, force the
256 function address into a register now. */
257 funexp = ((reg_parm_seen
261 }
262 else
263 {
264 /* funexp could be a SYMBOL_REF represents a function pointer which is
265 of ptr_mode. In this case, it should be converted into address mode
266 to be a valid address for memory rtx pattern. See PR 64971. */
271 {
274 }
275 }
280 {
281 rtx chain;
288 {
291 }
292 }
295 }
297 /* Generate instructions to call function FUNEXP,
298 and optionally pop the results.
299 The CALL_INSN is the first insn generated.
301 FNDECL is the declaration node of the function. This is given to the
302 hook TARGET_RETURN_POPS_ARGS to determine whether this function pops
303 its own args.
305 FUNTYPE is the data type of the function. This is given to the hook
306 TARGET_RETURN_POPS_ARGS to determine whether this function pops its
307 own args. We used to allow an identifier for library functions, but
308 that doesn't work when the return type is an aggregate type and the
309 calling convention says that the pointer to this aggregate is to be
310 popped by the callee.
312 STACK_SIZE is the number of bytes of arguments on the stack,
313 ROUNDED_STACK_SIZE is that number rounded up to
314 PREFERRED_STACK_BOUNDARY; zero if the size is variable. This is
315 both to put into the call insn and to generate explicit popping
316 code if necessary.
318 STRUCT_VALUE_SIZE is the number of bytes wanted in a structure value.
319 It is zero if this call doesn't want a structure value.
321 NEXT_ARG_REG is the rtx that results from executing
322 targetm.calls.function_arg (&args_so_far, VOIDmode, void_type_node, true)
323 just after all the args have had their registers assigned.
324 This could be whatever you like, but normally it is the first
325 arg-register beyond those used for args in this call,
326 or 0 if all the arg-registers are used in this call.
327 It is passed on to `gen_call' so you can put this info in the call insn.
329 VALREG is a hard register in which a value is returned,
330 or 0 if the call does not return a value.
332 OLD_INHIBIT_DEFER_POP is the value that `inhibit_defer_pop' had before
333 the args to this call were processed.
334 We restore `inhibit_defer_pop' to that value.
336 CALL_FUSAGE is either empty or an EXPR_LIST of USE expressions that
337 denote registers used by the called function. */
339 static void
341 tree funtype ATTRIBUTE_UNUSED,
342 HOST_WIDE_INT stack_size ATTRIBUTE_UNUSED,
343 HOST_WIDE_INT rounded_stack_size,
344 HOST_WIDE_INT struct_value_size ATTRIBUTE_UNUSED,
347 cumulative_args_t args_so_far ATTRIBUTE_UNUSED)
348 {
354 /* Sibling call patterns never pop arguments (no sibcall(_value)_pop
355 patterns exist). Any popping that the callee does on return will
356 be from our caller's frame rather than ours. */
358 {
361 #ifdef CALL_POPS_ARGS
363 #endif
364 }
366 /* Ensure address is valid. SYMBOL_REF is already valid, so no need,
367 and we don't want to load it into a register as an optimization,
368 because prepare_call_address already did it if it should be done. */
374 {
377 /* Although a built-in FUNCTION_DECL and its non-__builtin
378 counterpart compare equal and get a shared mem_attrs, they
379 produce different dump output in compare-debug compilations,
380 if an entry gets garbage collected in one compilation, then
381 adds a different (but equivalent) entry, while the other
382 doesn't run the garbage collector at the same spot and then
383 shares the mem_attr with the equivalent entry. */
385 {
389 }
392 }
397 {
400 rounded_stack_size_rtx,
402 else
405 }
406 /* If the target has "call" or "call_value" insns, then prefer them
407 if no arguments are actually popped. If the target does not have
408 "call" or "call_value" insns, then we must use the popping versions
409 even if the call has no arguments to pop. */
411 || !(valreg
414 {
417 /* If this subroutine pops its own args, record that in the call insn
418 if possible, for the sake of frame pointer elimination. */
422 rounded_stack_size_rtx,
424 else
429 }
430 else
431 {
435 else
438 }
441 /* Find the call we just emitted. */
444 /* Some target create a fresh MEM instead of reusing the one provided
445 above. Set its MEM_EXPR. */
452 /* Mark instrumented calls. */
456 /* Put the register usage information there. */
459 /* If this is a const call, then set the insn's unchanging bit. */
463 /* If this is a pure call, then set the insn's unchanging bit. */
467 /* If this is a const call, then set the insn's unchanging bit. */
471 /* Create a nothrow REG_EH_REGION note, if needed. */
478 {
481 }
485 /* Restore this now, so that we do defer pops for this call's args
486 if the context of the call as a whole permits. */
490 {
502 /* If popup is needed, stack realign must use DRAP */
505 }
506 /* For noreturn calls when not accumulating outgoing args force
507 REG_ARGS_SIZE note to prevent crossjumping of calls with different
508 args sizes. */
513 {
514 /* If returning from the subroutine does not automatically pop the args,
515 we need an instruction to pop them sooner or later.
516 Perhaps do it now; perhaps just record how much space to pop later.
518 If returning from the subroutine does pop the args, indicate that the
519 stack pointer will be changed. */
522 {
524 /* Just pretend we did the pop. */
529 else
531 }
532 }
533 /* When we accumulate outgoing args, we must avoid any stack manipulations.
534 Restore the stack pointer to its original value now. Usually
535 ACCUMULATE_OUTGOING_ARGS targets don't get here, but there are exceptions.
536 On i386 ACCUMULATE_OUTGOING_ARGS can be enabled on demand, and
537 popping variants of functions exist as well.
539 ??? We may optimize similar to defer_pop above, but it is
540 probably not worthwhile.
542 ??? It will be worthwhile to enable combine_stack_adjustments even for
543 such machines. */
546 }
548 /* Determine if the function identified by FNDECL is one with
549 special properties we wish to know about. Modify FLAGS accordingly.
551 For example, if the function might return more than one time (setjmp), then
552 set ECF_RETURNS_TWICE.
554 Set ECF_MAY_BE_ALLOCA for any memory allocation function that might allocate
555 space from the stack such as alloca. */
557 static int
559 {
562 /* For instrumentation clones we want to derive flags
563 from the original name. */
570 /* Exclude functions not at the file scope, or not `extern',
571 since they are not the magic functions we would otherwise
572 think they are.
573 FIXME: this should be handled with attributes, not with this
574 hacky imitation of DECL_ASSEMBLER_NAME. It's (also) wrong
575 because you can declare fork() inside a function if you
576 wish. */
580 {
584 /* We assume that alloca will always be called by name. It
585 makes no sense to pass it as a pointer-to-function to
586 anything that does not understand its behavior. */
592 /* Disregard prefix _ or __. */
594 {
597 else
599 }
601 /* ECF_RETURNS_TWICE is safe even for -ffreestanding. */
608 }
612 {
619 }
622 }
624 /* Similar to special_function_p; return a set of ERF_ flags for the
625 function FNDECL. */
626 static int
628 {
629 tree attr;
643 {
656 }
657 }
659 /* Return nonzero when FNDECL represents a call to setjmp. */
661 int
663 {
667 }
670 /* Return true if STMT may be an alloca call. */
672 bool
674 {
675 tree fndecl;
685 }
687 /* Return true if STMT is a builtin alloca call. */
689 bool
691 {
692 tree fndecl;
700 {
706 }
709 }
711 /* Return true when exp contains a builtin alloca call. */
713 bool
715 {
716 tree fndecl;
721 {
727 }
730 }
732 /* Return TRUE if FNDECL is either a TM builtin or a TM cloned
733 function. Return FALSE otherwise. */
735 static bool
737 {
745 {
747 {
790 }
791 }
793 }
795 /* Detect flags (function attributes) from the function decl or type node. */
797 int
799 {
803 {
804 /* The function exp may have the `malloc' attribute. */
808 /* The function exp may have the `returns_twice' attribute. */
812 /* Process the pure and const attributes. */
831 {
838 }
841 }
843 {
851 }
852 else
856 {
860 }
863 }
865 /* Detect flags from a CALL_EXPR. */
867 int
869 {
877 else
878 {
882 else
886 }
889 }
891 /* Return true if TYPE should be passed by invisible reference. */
893 bool
896 {
898 {
899 /* If this type contains non-trivial constructors, then it is
900 forbidden for the middle-end to create any new copies. */
904 /* GCC post 3.4 passes *all* variable sized types by reference. */
908 /* If a record type should be passed the same as its first (and only)
909 member, use the type and mode of that member. */
911 {
914 }
915 }
919 }
921 /* Return true if TYPE, which is passed by reference, should be callee
922 copied instead of caller copied. */
924 bool
927 {
931 named_arg);
932 }
935 /* Precompute all register parameters as described by ARGS, storing values
936 into fields within the ARGS array.
938 NUM_ACTUALS indicates the total number elements in the ARGS array.
940 Set REG_PARM_SEEN if we encounter a register parameter. */
942 static void
945 {
952 {
956 {
961 }
963 /* If we are to promote the function arg to a wider mode,
964 do it now. */
972 /* If the value is a non-legitimate constant, force it into a
973 pseudo now. TLS symbols sometimes need a call to resolve. */
978 /* If we're going to have to load the value by parts, pull the
979 parts into pseudos. The part extraction process can involve
980 non-trivial computation. */
982 {
987 }
989 /* If the value is expensive, and we are inside an appropriately
990 short loop, put the value into a pseudo and then put the pseudo
991 into the hard reg.
993 For small register classes, also do this if this call uses
994 register parameters. This is to avoid reload conflicts while
995 loading the parameters registers. */
1004 && ((*reg_parm_seen
1008 }
1009 }
1011 #ifdef REG_PARM_STACK_SPACE
1013 /* The argument list is the property of the called routine and it
1014 may clobber it. If the fixed area has been used for previous
1015 parameters, we must save and restore it. */
1017 static rtx
1018 save_fixed_argument_area (int reg_parm_stack_space, rtx argblock, int *low_to_save, int *high_to_save)
1019 {
1023 /* Compute the boundary of the area that needs to be saved, if any. */
1033 {
1035 machine_mode save_mode;
1037 rtx addr;
1038 rtx stack_area;
1039 rtx save_area;
1042 ;
1049 /* If we don't have the required alignment, must do this
1050 in BLKmode. */
1051 scalar_int_mode imode;
1056 else
1061 else
1069 {
1073 }
1074 else
1075 {
1078 }
1081 }
1084 }
1086 static void
1088 {
1095 else
1104 else
1107 BLOCK_OP_CALL_PARM);
1108 }
1111 /* If any elements in ARGS refer to parameters that are to be passed in
1112 registers, but not in memory, and whose alignment does not permit a
1113 direct copy into registers. Copy the values into a group of pseudos
1114 which we will later copy into the appropriate hard registers.
1116 Pseudos for each unaligned argument will be stored into the array
1117 args[argnum].aligned_regs. The caller is responsible for deallocating
1118 the aligned_regs array if it is nonzero. */
1120 static void
1122 {
1132 {
1137 {
1140 }
1141 else
1142 {
1145 }
1149 /* Structures smaller than a word are normally aligned to the
1150 least significant byte. On a BYTES_BIG_ENDIAN machine,
1151 this means we must skip the empty high order bytes when
1152 calculating the bit offset. */
1154 #ifdef BLOCK_REG_PADDING
1158 #else
1159 && BYTES_BIG_ENDIAN
1160 #endif
1161 )
1165 {
1174 /* There is no need to restrict this code to loading items
1175 in TYPE_ALIGN sized hunks. The bitfield instructions can
1176 load up entire word sized registers efficiently.
1178 ??? This may not be needed anymore.
1179 We use to emit a clobber here but that doesn't let later
1180 passes optimize the instructions we emit. By storing 0 into
1181 the register later passes know the first AND to zero out the
1182 bitfield being set in the register is unnecessary. The store
1183 of 0 will be deleted as will at least the first AND. */
1190 }
1191 }
1192 }
1194 /* The limit set by -Walloc-larger-than=. */
1197 /* Initialize ALLOC_OBJECT_SIZE_LIMIT based on the -Walloc-size-larger-than=
1198 setting if the option is specified, or to the maximum object size if it
1199 is not. Return the initialized value. */
1201 static tree
1203 {
1205 {
1209 {
1213 unsigned HOST_WIDE_INT limit
1217 {
1219 {
1220 /* Numeric option arguments are at most INT_MAX. Make it
1221 possible to specify a larger value by accepting common
1222 suffixes. */
1249 else
1251 }
1254 {
1258 }
1259 }
1260 }
1261 }
1263 }
1265 /* Return true when EXP's range can be determined and set RANGE[] to it
1266 after adjusting it if necessary to make EXP a valid size argument to
1267 an allocation function declared with attribute alloc_size (whose
1268 argument may be signed), or to a string manipulation function like
1269 memset. */
1271 bool
1273 {
1275 {
1276 /* EXP is a constant. */
1279 }
1282 enum value_range_type range_type
1287 {
1288 /* No range information available. */
1292 }
1302 {
1304 {
1306 {
1307 /* EXP is not in a strictly negative range. That means
1308 it must be in some (not necessarily strictly) positive
1309 range which includes zero. Since in signed to unsigned
1310 conversions negative values end up converted to large
1311 positive values, and otherwise they are not valid sizes,
1312 the resulting range is in both cases [0, TYPE_MAX]. */
1315 }
1317 {
1318 /* EXP is not in a negative-positive range. That means EXP
1319 is either negative, or greater than max. Since negative
1320 sizes are invalid make the range [MAX + 1, TYPE_MAX]. */
1323 }
1324 else
1325 {
1328 }
1329 }
1331 {
1332 /* EXP is unsigned and not in the range [1, MAX]. That means
1333 it's either zero or greater than MAX. Even though 0 would
1334 normally be detected by -Walloc-zero set the range to
1335 [MAX, TYPE_MAX] so that when MAX is greater than the limit
1336 the whole range is diagnosed. */
1339 }
1340 else
1341 {
1344 }
1345 }
1351 }
1353 /* Diagnose a call EXP to function FN decorated with attribute alloc_size
1354 whose argument numbers given by IDX with values given by ARGS exceed
1355 the maximum object size or cause an unsigned oveflow (wrapping) when
1356 multiplied. When ARGS[0] is null the function does nothing. ARGS[1]
1357 may be null for functions like malloc, and non-null for those like
1358 calloc that are decorated with a two-argument attribute alloc_size. */
1360 void
1362 {
1363 /* The range each of the (up to) two arguments is known to be in. */
1366 /* Maximum object size set by -Walloc-size-larger-than= or SIZE_MAX / 2. */
1373 /* Validate each argument individually. */
1375 {
1377 {
1382 {
1386 }
1388 {
1389 /* Avoid issuing -Walloc-zero for allocation functions other
1390 than __builtin_alloca that are declared with attribute
1391 returns_nonnull because there's no portability risk. This
1392 avoids warning for such calls to libiberty's xmalloc and
1393 friends.
1394 Also avoid issuing the warning for calls to function named
1395 "alloca". */
1404 }
1406 {
1407 /* G++ emits calls to ::operator new[](SIZE_MAX) in C++98
1408 mode and with -fno-exceptions as a way to indicate array
1409 size overflow. There's no good way to detect C++98 here
1410 so avoid diagnosing these calls for all C++ modes. */
1419 "%Kargument %i value %qE exceeds "
1422 }
1423 }
1426 {
1427 /* Verify that the argument's range is not negative (including
1428 upper bound of zero). */
1431 {
1436 }
1438 {
1440 "%Kargument %i range [%E, %E] exceeds "
1444 maxobjsize);
1445 }
1446 }
1447 }
1452 /* For a two-argument alloc_size, validate the product of the two
1453 arguments if both of their values or ranges are known. */
1458 {
1459 /* Check for overflow in the product of a function decorated with
1460 attribute alloc_size (X, Y). */
1470 "%Kproduct %<%E * %E%> of arguments %i and %i "
1476 "%Kproduct %<%E * %E%> of arguments %i and %i "
1480 maxobjsize);
1483 {
1484 /* Print the full range of each of the two arguments to make
1485 it clear when it is, in fact, in a range and not constant. */
1492 }
1493 }
1496 {
1502 else
1505 }
1506 }
1508 /* Issue an error if CALL_EXPR was flagged as requiring
1509 tall-call optimization. */
1511 static void
1513 {
1519 }
1521 /* Fill in ARGS_SIZE and ARGS array based on the parameters found in
1522 CALL_EXPR EXP.
1524 NUM_ACTUALS is the total number of parameters.
1526 N_NAMED_ARGS is the total number of named arguments.
1528 STRUCT_VALUE_ADDR_VALUE is the implicit argument for a struct return
1529 value, or null.
1531 FNDECL is the tree code for the target of this call (if known)
1533 ARGS_SO_FAR holds state needed by the target to know where to place
1534 the next argument.
1536 REG_PARM_STACK_SPACE is the number of bytes of stack space reserved
1537 for arguments which are passed in registers.
1539 OLD_STACK_LEVEL is a pointer to an rtx which olds the old stack level
1540 and may be modified by this routine.
1542 OLD_PENDING_ADJ, MUST_PREALLOCATE and FLAGS are pointers to integer
1543 flags which may be modified by this routine.
1545 MAY_TAILCALL is cleared if we encounter an invisible pass-by-reference
1546 that requires allocation of stack space.
1548 CALL_FROM_THUNK_P is true if this call is the jump from a thunk to
1549 the thunked-to function. */
1551 static void
1558 cumulative_args_t args_so_far,
1563 {
1567 /* Count arg position in order args appear. */
1577 /* In this loop, we consider args in the order they are written.
1578 We fill up ARGS from the back. */
1581 {
1583 call_expr_arg_iterator iter;
1584 tree arg;
1588 {
1590 j--;
1592 /* If we pass structure address then we need to
1593 create bounds for it. Since created bounds is
1594 a call statement, we expand it right here to avoid
1595 fixing all other places where it may be expanded. */
1597 {
1604 j--;
1605 }
1606 }
1609 {
1612 /* Remember last param with pointer and associate it
1613 with following pointer bounds. */
1616 {
1621 {
1624 }
1625 }
1629 {
1633 }
1635 {
1636 /* We expect bounds in instrumented calls only.
1637 Otherwise it is a sign we lost flag due to some optimization
1638 and may emit call args incorrectly. */
1641 /* For structures look for the next available pointer. */
1643 {
1650 /* Check we have no more pointers in the structure. */
1653 }
1656 /* Check we covered all pointers in the previous
1657 non bounds arg. */
1660 }
1661 else
1665 && argtype
1668 {
1671 j--;
1673 }
1674 else
1676 j--;
1677 argpos++;
1678 }
1682 }
1686 /* Extract attribute alloc_size and if set, store the indices of
1687 the corresponding arguments in ALLOC_IDX, and then the actual
1688 argument(s) at those indices in ALLOC_ARGS. */
1694 {
1699 }
1701 /* Array for up to the two attribute alloc_size arguments. */
1704 /* I counts args in order (to be) pushed; ARGPOS counts in order written. */
1706 {
1709 machine_mode mode;
1711 /* Replace erroneous argument with constant zero. */
1715 /* If TYPE is a transparent union or record, pass things the way
1716 we would pass the first field of the union or record. We have
1717 already verified that the modes are the same. */
1722 /* Decide where to pass this arg.
1724 args[i].reg is nonzero if all or part is passed in registers.
1726 args[i].partial is nonzero if part but not all is passed in registers,
1727 and the exact value says how many bytes are passed in registers.
1729 args[i].pass_on_stack is nonzero if the argument must at least be
1730 computed on the stack. It may then be loaded back into registers
1731 if args[i].reg is nonzero.
1733 These decisions are driven by the FUNCTION_... macros and must agree
1734 with those made by function.c. */
1736 /* See if this argument should be passed by invisible reference. */
1739 {
1743 callee_copies
1747 /* If we're compiling a thunk, pass through invisible references
1748 instead of making a copy. */
1750 || (callee_copies
1755 {
1756 /* We may have turned the parameter value into an SSA name.
1757 Go back to the original parameter so we can take the
1758 address. */
1760 {
1764 }
1765 /* Argument setup code may have copied the value to register. We
1766 revert that optimization now because the tail call code must
1767 use the original location. */
1777 /* We can't use sibcalls if a callee-copied argument is
1778 stored in the current function's frame. */
1780 {
1783 "a callee-copied argument is"
1784 " stored in the current "
1786 }
1794 }
1795 else
1796 {
1797 /* We make a copy of the object and pass the address to the
1798 function being called. */
1799 rtx copy;
1806 {
1807 /* This is a variable-sized object. Make space on the stack
1808 for it. */
1812 {
1816 }
1818 /* We can pass TRUE as the 4th argument because we just
1819 saved the stack pointer and will restore it right after
1820 the call. */
1827 }
1828 else
1833 /* Just change the const function to pure and then let
1834 the next test clear the pure based on
1835 callee_copies. */
1837 {
1840 }
1850 "argument must be passed"
1852 }
1853 }
1866 {
1869 }
1871 /* If this is a sibling call and the machine has register windows, the
1872 register window has to be unwinded before calling the routine, so
1873 arguments have to go into the incoming registers. */
1878 else
1888 /* If FUNCTION_ARG returned a (parallel [(expr_list (nil) ...) ...]),
1889 it means that we are to pass this arg in the register(s) designated
1890 by the PARALLEL, but also to pass it in the stack. */
1895 /* If this is an addressable type, we must preallocate the stack
1896 since we must evaluate the object into its final location.
1898 If this is to be passed in both registers and the stack, it is simpler
1899 to preallocate. */
1904 /* No stack allocation and padding for bounds. */
1906 ;
1907 /* Compute the stack-size of this argument. */
1912 #ifdef STACK_PARMS_IN_REG_PARM_AREA
1914 #else
1916 #endif
1917 reg_parm_stack_space,
1920 #ifdef BLOCK_REG_PADDING
1921 else
1922 /* The argument is passed entirely in registers. See at which
1923 end it should be padded. */
1927 #endif
1929 /* Update ARGS_SIZE, the total stack space for args so far. */
1935 /* Increment ARGS_SO_FAR, which has info about which arg-registers
1936 have been used, etc. */
1941 /* Store argument values for functions decorated with attribute
1942 alloc_size. */
1947 }
1950 {
1951 /* Check the arguments of functions decorated with attribute
1952 alloc_size. */
1954 }
1955 }
1957 /* Update ARGS_SIZE to contain the total size for the argument block.
1958 Return the original constant component of the argument block's size.
1960 REG_PARM_STACK_SPACE holds the number of bytes of stack space reserved
1961 for arguments passed in registers. */
1963 static int
1966 tree fndecl ATTRIBUTE_UNUSED,
1967 tree fntype ATTRIBUTE_UNUSED,
1969 {
1972 /* For accumulate outgoing args mode we don't need to align, since the frame
1973 will be already aligned. Align to STACK_BOUNDARY in order to prevent
1974 backends from generating misaligned frame sizes. */
1978 /* Compute the actual size of the argument block required. The variable
1979 and constant sizes must be combined, the size may have to be rounded,
1980 and there may be a minimum required size. */
1983 {
1989 {
1990 /* We don't handle this case yet. To handle it correctly we have
1991 to add the delta, round and subtract the delta.
1992 Currently no machine description requires this support. */
1995 }
1998 {
1999 args_size->var
2003 /* The area corresponding to register parameters is not to count in
2004 the size of the block we need. So make the adjustment. */
2006 args_size->var
2009 }
2010 }
2011 else
2012 {
2017 + stack_pointer_delta
2019 / preferred_stack_boundary
2024 reg_parm_stack_space);
2028 }
2030 }
2032 /* Precompute parameters as needed for a function call.
2034 FLAGS is mask of ECF_* constants.
2036 NUM_ACTUALS is the number of arguments.
2038 ARGS is an array containing information for each argument; this
2039 routine fills in the INITIAL_VALUE and VALUE fields for each
2040 precomputed argument. */
2042 static void
2044 {
2047 /* If this is a libcall, then precompute all arguments so that we do not
2048 get extraneous instructions emitted as part of the libcall sequence. */
2050 /* If we preallocated the stack space, and some arguments must be passed
2051 on the stack, then we must precompute any parameter which contains a
2052 function call which will store arguments on the stack.
2053 Otherwise, evaluating the parameter may clobber previous parameters
2054 which have already been stored into the stack. (we have code to avoid
2055 such case by saving the outgoing stack arguments, but it results in
2056 worse code) */
2061 {
2062 tree type;
2063 machine_mode mode;
2068 /* If this is an addressable type, we cannot pre-evaluate it. */
2077 {
2083 /* CSE will replace this only if it contains args[i].value
2084 pseudo, so convert it down to the declared mode using
2085 a SUBREG. */
2089 {
2094 }
2095 }
2096 }
2097 }
2099 /* Given the current state of MUST_PREALLOCATE and information about
2100 arguments to a function call in NUM_ACTUALS, ARGS and ARGS_SIZE,
2101 compute and return the final value for MUST_PREALLOCATE. */
2103 static int
2106 {
2107 /* See if we have or want to preallocate stack space.
2109 If we would have to push a partially-in-regs parm
2110 before other stack parms, preallocate stack space instead.
2112 If the size of some parm is not a multiple of the required stack
2113 alignment, we must preallocate.
2115 If the total size of arguments that would otherwise create a copy in
2116 a temporary (such as a CALL) is more than half the total argument list
2117 size, preallocation is faster.
2119 Another reason to preallocate is if we have a machine (like the m88k)
2120 where stack alignment is required to be maintained between every
2121 pair of insns, not just when the call is made. However, we assume here
2122 that such machines either do not have push insns (and hence preallocation
2123 would occur anyway) or the problem is taken care of with
2124 PUSH_ROUNDING. */
2127 {
2133 {
2138 /* We preallocate in case there are bounds passed
2139 in the bounds table to have precomputed address
2140 for bounds association. */
2150 copy_to_evaluate_size
2152 }
2157 }
2159 }
2161 /* If we preallocated stack space, compute the address of each argument
2162 and store it into the ARGS array.
2164 We need not ensure it is a valid memory address here; it will be
2165 validized when it is used.
2167 ARGBLOCK is an rtx for the address of the outgoing arguments. */
2169 static void
2171 {
2173 {
2181 {
2184 rtx addr;
2189 /* Skip this parm if it will not be passed on the stack. */
2195 /* Pointer Bounds are never passed on the stack. */
2203 {
2204 /* Only part of the parameter is being passed on the stack.
2205 Generate a simple memory reference of the correct size. */
2211 }
2212 else
2213 {
2217 }
2223 {
2226 }
2233 {
2234 /* Only part of the parameter is being passed on the stack.
2235 Generate a simple memory reference of the correct size.
2236 */
2239 }
2240 else
2241 {
2245 }
2248 /* Function incoming arguments may overlap with sibling call
2249 outgoing arguments and we cannot allow reordering of reads
2250 from function arguments with stores to outgoing arguments
2251 of sibling calls. */
2254 }
2255 }
2256 }
2258 /* Given a FNDECL and EXP, return an rtx suitable for use as a target address
2259 in a call instruction.
2261 FNDECL is the tree node for the target function. For an indirect call
2262 FNDECL will be NULL_TREE.
2264 ADDR is the operand 0 of CALL_EXPR for this call. */
2266 static rtx
2268 {
2269 rtx funexp;
2271 /* Get the function to call, in the form of RTL. */
2273 {
2277 /* Get a SYMBOL_REF rtx for the function address. */
2279 }
2280 else
2281 /* Generate an rtx (probably a pseudo-register) for the address. */
2282 {
2286 }
2288 }
2290 /* Internal state for internal_arg_pointer_based_exp and its helpers. */
2291 static struct
2292 {
2293 /* Last insn that has been scanned by internal_arg_pointer_based_exp_scan,
2294 or NULL_RTX if none has been scanned yet. */
2296 /* Vector indexed by REGNO - FIRST_PSEUDO_REGISTER, recording if a pseudo is
2297 based on crtl->args.internal_arg_pointer. The element is NULL_RTX if the
2298 pseudo isn't based on it, a CONST_INT offset if the pseudo is based on it
2299 with fixed offset, or PC if this is with variable or unknown offset. */
2305 /* Helper function for internal_arg_pointer_based_exp. Scan insns in
2306 the tail call sequence, starting with first insn that hasn't been
2307 scanned yet, and note for each pseudo on the LHS whether it is based
2308 on crtl->args.internal_arg_pointer or not, and what offset from that
2309 that pointer it has. */
2311 static void
2313 {
2318 else
2322 {
2325 {
2328 /* Punt on pseudos set multiple times. */
2333 else
2336 {
2338 internal_arg_pointer_exp_state.cache
2341 }
2342 }
2346 }
2349 }
2351 /* Compute whether RTL is based on crtl->args.internal_arg_pointer. Return
2352 NULL_RTX if RTL isn't based on it, a CONST_INT offset if RTL is based on
2353 it with fixed offset, or PC if this is with variable or unknown offset.
2354 TOPLEVEL is true if the function is invoked at the topmost level. */
2356 static rtx
2358 {
2369 {
2374 }
2376 /* When called at the topmost level, scan pseudo assignments in between the
2377 last scanned instruction in the tail call sequence and the latest insn
2378 in that sequence. */
2383 {
2389 }
2393 {
2399 }
2402 }
2404 /* Return true if and only if SIZE storage units (usually bytes)
2405 starting from address ADDR overlap with already clobbered argument
2406 area. This function is used to determine if we should give up a
2407 sibcall. */
2409 static bool
2411 {
2412 HOST_WIDE_INT i;
2413 rtx val;
2422 else
2427 else
2435 {
2442 }
2445 }
2447 /* Do the register loads required for any wholly-register parms or any
2448 parms which are passed both on the stack and in a register. Their
2449 expressions were already evaluated.
2451 Mark all register-parms as living through the call, putting these USE
2452 insns in the CALL_INSN_FUNCTION_USAGE field.
2454 When IS_SIBCALL, perform the check_sibcall_argument_overlap
2455 checking, setting *SIBCALL_FAILURE if appropriate. */
2457 static void
2461 {
2465 {
2469 {
2474 /* Set non-negative if we must move a word at a time, even if
2475 just one word (e.g, partial == 4 && mode == DFmode). Set
2476 to -1 if we just use a normal move insn. This value can be
2477 zero if the argument is a zero size structure. */
2480 ;
2482 {
2485 }
2487 {
2490 }
2491 else
2494 /* Handle calls that pass values in multiple non-contiguous
2495 locations. The Irix 6 ABI has examples of this. */
2500 /* If simple case, just do move. If normal partial, store_one_arg
2501 has already loaded the register for us. In all other cases,
2502 load the register(s) from memory. */
2505 {
2507 #ifdef BLOCK_REG_PADDING
2508 /* Handle case where we have a value that needs shifting
2509 up to the msb. eg. a QImode value and we're padding
2510 upward on a BYTES_BIG_ENDIAN machine. */
2514 {
2515 rtx x;
2518 /* Assigning REG here rather than a temp makes CALL_FUSAGE
2519 report the whole reg as used. Strictly speaking, the
2520 call only uses SIZE bytes at the msb end, but it doesn't
2521 seem worth generating rtl to say that. */
2526 }
2527 #endif
2528 }
2530 /* If we have pre-computed the values to put in the registers in
2531 the case of non-aligned structures, copy them in now. */
2539 {
2542 /* Check for overlap with already clobbered argument area,
2543 providing that this has non-zero size. */
2546 && (mem_overlaps_already_clobbered_arg_p
2553 else
2554 {
2563 NULL);
2569 }
2571 /* Handle a BLKmode that needs shifting. */
2573 #ifdef BLOCK_REG_PADDING
2575 #else
2576 && BYTES_BIG_ENDIAN
2577 #endif
2578 )
2579 {
2584 rtx x;
2589 }
2590 }
2592 /* When a parameter is a block, and perhaps in other cases, it is
2593 possible that it did a load from an argument slot that was
2594 already clobbered. */
2599 /* Handle calls that pass values in multiple non-contiguous
2600 locations. The Irix 6 ABI has examples of this. */
2608 }
2609 }
2610 }
2612 /* We need to pop PENDING_STACK_ADJUST bytes. But, if the arguments
2613 wouldn't fill up an even multiple of PREFERRED_UNIT_STACK_BOUNDARY
2614 bytes, then we would need to push some additional bytes to pad the
2615 arguments. So, we compute an adjust to the stack pointer for an
2616 amount that will leave the stack under-aligned by UNADJUSTED_ARGS_SIZE
2617 bytes. Then, when the arguments are pushed the stack will be perfectly
2618 aligned. ARGS_SIZE->CONSTANT is set to the number of bytes that should
2619 be popped after the call. Returns the adjustment. */
2621 static int
2625 {
2626 /* The number of bytes to pop so that the stack will be
2627 under-aligned by UNADJUSTED_ARGS_SIZE bytes. */
2628 HOST_WIDE_INT adjustment;
2629 /* The alignment of the stack after the arguments are pushed, if we
2630 just pushed the arguments without adjust the stack here. */
2633 unadjusted_alignment
2637 /* We want to get rid of as many of the PENDING_STACK_ADJUST bytes
2638 as possible -- leaving just enough left to cancel out the
2639 UNADJUSTED_ALIGNMENT. In other words, we want to ensure that the
2640 PENDING_STACK_ADJUST is non-negative, and congruent to
2641 -UNADJUSTED_ALIGNMENT modulo the PREFERRED_UNIT_STACK_BOUNDARY. */
2643 /* Begin by trying to pop all the bytes. */
2644 unadjusted_alignment
2645 = (unadjusted_alignment
2648 /* Push enough additional bytes that the stack will be aligned
2649 after the arguments are pushed. */
2653 /* Now, sets ARGS_SIZE->CONSTANT so that we pop the right number of
2654 bytes after the call. The right number is the entire
2655 PENDING_STACK_ADJUST less our ADJUSTMENT plus the amount required
2656 by the arguments in the first place. */
2657 args_size->constant
2661 }
2663 /* Scan X expression if it does not dereference any argument slots
2664 we already clobbered by tail call arguments (as noted in stored_args_map
2665 bitmap).
2666 Return nonzero if X expression dereferences such argument slots,
2667 zero otherwise. */
2669 static int
2671 {
2672 RTX_CODE code;
2681 /* We need not check the operands of the CALL expression itself. */
2689 /* Scan all subexpressions. */
2692 {
2694 {
2697 }
2699 {
2703 }
2704 }
2706 }
2708 /* Scan sequence after INSN if it does not dereference any argument slots
2709 we already clobbered by tail call arguments (as noted in stored_args_map
2710 bitmap). If MARK_STORED_ARGS_MAP, add stack slots for ARG to
2711 stored_args_map bitmap afterwards (when ARG is a register MARK_STORED_ARGS_MAP
2712 should be 0). Return nonzero if sequence after INSN dereferences such argument
2713 slots, zero otherwise. */
2715 static int
2718 {
2723 else
2732 {
2735 else
2740 }
2742 }
2744 /* Given that a function returns a value of mode MODE at the most
2745 significant end of hard register VALUE, shift VALUE left or right
2746 as specified by LEFT_P. Return true if some action was needed. */
2748 bool
2750 {
2751 HOST_WIDE_INT shift;
2758 /* Use ashr rather than lshr for right shifts. This is for the benefit
2759 of the MIPS port, which requires SImode values to be sign-extended
2760 when stored in 64-bit registers. */
2765 }
2767 /* If X is a likely-spilled register value, copy it to a pseudo
2768 register and return that register. Return X otherwise. */
2770 static rtx
2772 {
2773 rtx new_rtx;
2778 {
2779 /* Make sure that we generate a REG rather than a CONCAT.
2780 Moves into CONCATs can need nontrivial instructions,
2781 and the whole point of this function is to avoid
2782 using the hard register directly in such a situation. */
2788 }
2790 }
2792 /* Helper function for expand_call.
2793 Return false is EXP is not implementable as a sibling call. */
2795 static bool
2797 rtx structure_value_addr,
2798 tree funtype,
2800 tree fndecl,
2802 tree addr,
2804 {
2806 {
2807 maybe_complain_about_tail_call
2809 "machine description does not have"
2812 }
2814 /* Doing sibling call optimization needs some work, since
2815 structure_value_addr can be allocated on the stack.
2816 It does not seem worth the effort since few optimizable
2817 sibling calls will return a structure. */
2819 {
2822 }
2824 #ifdef REG_PARM_STACK_SPACE
2825 /* If outgoing reg parm stack space changes, we can not do sibcall. */
2829 {
2831 "inconsistent size of stack space"
2832 " allocated for arguments which are"
2835 }
2836 #endif
2838 /* Check whether the target is able to optimize the call
2839 into a sibcall. */
2841 {
2843 "target is not able to optimize the"
2846 }
2848 /* Functions that do not return exactly once may not be sibcall
2849 optimized. */
2851 {
2854 }
2856 {
2859 }
2862 {
2865 }
2867 /* If the called function is nested in the current one, it might access
2868 some of the caller's arguments, but could clobber them beforehand if
2869 the argument areas are shared. */
2871 {
2874 }
2876 /* If this function requires more stack slots than the current
2877 function, we cannot change it into a sibling call.
2878 crtl->args.pretend_args_size is not part of the
2879 stack allocated by our caller. */
2881 {
2883 "callee required more stack slots"
2886 }
2888 /* If the callee pops its own arguments, then it must pop exactly
2889 the same number of arguments as the current function. */
2894 {
2896 "inconsistent number of"
2899 }
2902 {
2906 }
2908 /* All checks passed. */
2910 }
2912 /* Generate all the code for a CALL_EXPR exp
2913 and return an rtx for its value.
2914 Store the value in TARGET (specified as an rtx) if convenient.
2915 If the value is stored in TARGET then TARGET is returned.
2916 If IGNORE is nonzero, then we ignore the value of the function call. */
2918 rtx
2920 {
2921 /* Nonzero if we are currently expanding a call. */
2924 /* RTX for the function to be called. */
2925 rtx funexp;
2926 /* Sequence of insns to perform a normal "call". */
2928 /* Sequence of insns to perform a tail "call". */
2930 /* Data type of the function. */
2931 tree funtype;
2932 tree type_arg_types;
2933 tree rettype;
2934 /* Declaration of the function being called,
2935 or 0 if the function is computed (not known by name). */
2937 /* The type of the function being called. */
2938 tree fntype;
2943 /* Register in which non-BLKmode value will be returned,
2944 or 0 if no value or if value is BLKmode. */
2945 rtx valreg;
2946 /* Register(s) in which bounds are returned. */
2948 /* Address where we should return a BLKmode value;
2949 0 if value not BLKmode. */
2951 /* Nonzero if that address is being passed by treating it as
2952 an extra, implicit first parameter. Otherwise,
2953 it is passed by being copied directly into struct_value_rtx. */
2955 /* Holds the value of implicit argument for the struct value. */
2957 /* Size of aggregate value wanted, or zero if none wanted
2958 or if we are using the non-reentrant PCC calling convention
2959 or expecting the value in registers. */
2961 /* Nonzero if called function returns an aggregate in memory PCC style,
2962 by returning the address of where to find it. */
2966 /* Number of actual parameters in this call, including struct value addr. */
2968 /* Number of named args. Args after this are anonymous ones
2969 and they must all go on the stack. */
2971 /* Number of complex actual arguments that need to be split. */
2974 /* Vector of information about each argument.
2975 Arguments are numbered in the order they will be pushed,
2976 not the order they are written. */
2979 /* Total size in bytes of all the stack-parms scanned so far. */
2982 /* Size of arguments before any adjustments (such as rounding). */
2984 /* Data on reg parms scanned so far. */
2985 CUMULATIVE_ARGS args_so_far_v;
2986 cumulative_args_t args_so_far;
2987 /* Nonzero if a reg parm has been scanned. */
2989 /* Nonzero if this is an indirect function call. */
2991 /* Nonzero if we must avoid push-insns in the args for this call.
2992 If stack space is allocated for register parameters, but not by the
2993 caller, then it is preallocated in the fixed part of the stack frame.
2994 So the entire argument block must then be preallocated (i.e., we
2995 ignore PUSH_ROUNDING in that case). */
2999 /* Size of the stack reserved for parameter registers. */
3002 /* Address of space preallocated for stack parms
3003 (on machines that lack push insns), or 0 if space not preallocated. */
3006 /* Mask of ECF_ and ERF_ flags. */
3009 #ifdef REG_PARM_STACK_SPACE
3010 /* Define the boundary of the register parm stack space that needs to be
3011 saved, if any. */
3014 #endif
3022 /* State variables to track stack modifications. */
3028 /* Some stack pointer alterations we make are performed via
3029 allocate_dynamic_stack_space. This modifies the stack_pointer_delta,
3030 which we then also need to save/restore along the way. */
3033 rtx call_fusage;
3036 /* The alignment of the stack, in bits. */
3038 /* The alignment of the stack, in bytes. */
3040 /* The static chain value to use for this call. */
3041 rtx static_chain_value;
3042 /* See if this is "nothrow" function call. */
3046 /* See if we can find a DECL-node for the actual function, and get the
3047 function attributes (flags) from the function decl or type node. */
3050 {
3054 }
3055 else
3056 {
3061 }
3066 /* Warn if this value is an aggregate type,
3067 regardless of which calling convention we are using for it. */
3071 /* If the result of a non looping pure or const function call is
3072 ignored (or void), and none of its arguments are volatile, we can
3073 avoid expanding the call and just evaluate the arguments for
3074 side-effects. */
3079 {
3081 tree arg;
3082 call_expr_arg_iterator iter;
3086 {
3089 }
3092 {
3096 }
3097 }
3099 #ifdef REG_PARM_STACK_SPACE
3101 #endif
3107 /* Set up a place to return a structure. */
3109 /* Cater to broken compilers. */
3111 {
3112 /* This call returns a big structure. */
3115 #ifdef PCC_STATIC_STRUCT_RETURN
3116 {
3118 }
3120 {
3123 /* Even if it is semantically safe to use the target as the return
3124 slot, it may be not sufficiently aligned for the return type. */
3126 && target
3132 else
3133 {
3134 /* For variable-sized objects, we must be called with a target
3135 specified. If we were to allocate space on the stack here,
3136 we would have no way of knowing when to free it. */
3140 }
3141 }
3143 }
3145 /* Figure out the amount to which the stack should be aligned. */
3148 {
3150 /* Without automatic stack alignment, we can't increase preferred
3151 stack boundary. With automatic stack alignment, it is
3152 unnecessary since unless we can guarantee that all callers will
3153 align the outgoing stack properly, callee has to align its
3154 stack anyway. */
3159 }
3161 /* Operand 0 is a pointer-to-function; get the type of the function. */
3166 /* Count whether there are actual complex arguments that need to be split
3167 into their real and imaginary parts. Munge the type_arg_types
3168 appropriately here as well. */
3170 {
3171 call_expr_arg_iterator iter;
3172 tree arg;
3174 {
3178 num_complex_actuals++;
3179 }
3181 }
3182 else
3188 /* If struct_value_rtx is 0, it means pass the address
3189 as if it were an extra parameter. Put the argument expression
3190 in structure_value_addr_value. */
3192 {
3193 /* If structure_value_addr is a REG other than
3194 virtual_outgoing_args_rtx, we can use always use it. If it
3195 is not a REG, we must always copy it into a register.
3196 If it is virtual_outgoing_args_rtx, we must copy it to another
3197 register in some cases. */
3199 || (ACCUMULATE_OUTGOING_ARGS
3200 && stack_arg_under_construction
3206 structure_value_addr_value =
3209 }
3211 /* Count the arguments and set NUM_ACTUALS. */
3212 num_actuals =
3215 /* Compute number of named args.
3216 First, do a raw count of the args for INIT_CUMULATIVE_ARGS. */
3219 n_named_args
3221 /* Count the struct value address, if it is passed as a parm. */
3223 else
3224 /* If we know nothing, treat all args as named. */
3227 /* Start updating where the next arg would go.
3229 On some machines (such as the PA) indirect calls have a different
3230 calling convention than normal calls. The fourth argument in
3231 INIT_CUMULATIVE_ARGS tells the backend if this is an indirect call
3232 or not. */
3236 /* Now possibly adjust the number of named args.
3237 Normally, don't include the last named arg if anonymous args follow.
3238 We do include the last named arg if
3239 targetm.calls.strict_argument_naming() returns nonzero.
3240 (If no anonymous args follow, the result of list_length is actually
3241 one too large. This is harmless.)
3243 If targetm.calls.pretend_outgoing_varargs_named() returns
3244 nonzero, and targetm.calls.strict_argument_naming() returns zero,
3245 this machine will be able to place unnamed args that were passed
3246 in registers into the stack. So treat all args as named. This
3247 allows the insns emitting for a specific argument list to be
3248 independent of the function declaration.
3250 If targetm.calls.pretend_outgoing_varargs_named() returns zero,
3251 we do not have any reliable way to pass unnamed args in
3252 registers, so we must force them into memory. */
3256 ;
3259 /* Don't include the last named arg. */
3261 else
3262 /* Treat all args as named. */
3265 /* Make a vector to hold all the information about each arg. */
3268 /* Build up entries in the ARGS array, compute the size of the
3269 arguments into ARGS_SIZE, etc. */
3281 /* Now make final decision about preallocating stack space. */
3286 /* If the structure value address will reference the stack pointer, we
3287 must stabilize it. We don't need to do this if we know that we are
3288 not going to adjust the stack pointer in processing this call. */
3293 structure_value_addr))
3298 /* Tail calls can make things harder to debug, and we've traditionally
3299 pushed these optimizations into -O2. Don't try if we're already
3300 expanding a call, as that means we're an argument. Don't try if
3301 there's cleanups, as we know there's code to follow the call. */
3304 || !flag_optimize_sibling_calls
3309 /* If the user has marked the function as requiring tail-call
3310 optimization, attempt it. */
3314 /* Rest of purposes for tail call optimizations to fail. */
3317 structure_value_addr,
3318 funtype,
3319 reg_parm_stack_space,
3320 fndecl,
3323 /* Check if caller and callee disagree in promotion of function
3324 return value. */
3326 {
3336 caller_promoted_mode
3340 callee_promoted_mode
3350 {
3353 "caller and callee disagree in"
3354 " promotion of function"
3356 }
3357 }
3359 /* Ensure current function's preferred stack boundary is at least
3360 what we need. Stack alignment may also increase preferred stack
3361 boundary. */
3364 else
3369 /* We want to make two insn chains; one for a sibling call, the other
3370 for a normal call. We will select one of the two chains after
3371 initial RTL generation is complete. */
3373 {
3375 /* We want to emit any pending stack adjustments before the tail
3376 recursion "call". That way we know any adjustment after the tail
3377 recursion call can be ignored if we indeed use the tail
3378 call expansion. */
3379 saved_pending_stack_adjust save;
3381 rtx next_arg_reg;
3384 {
3385 /* State variables we need to save and restore between
3386 iterations. */
3388 }
3391 else
3394 /* Other state variables that we must reinitialize each time
3395 through the loop (that are not initialized by the loop itself). */
3399 /* Start a new sequence for the normal call case.
3401 From this point on, if the sibling call fails, we want to set
3402 sibcall_failure instead of continuing the loop. */
3405 /* Don't let pending stack adjusts add up to too much.
3406 Also, do all pending adjustments now if there is any chance
3407 this might be a call to alloca or if we are expanding a sibling
3408 call sequence.
3409 Also do the adjustments before a throwing call, otherwise
3410 exception handling can fail; PR 19225. */
3419 /* Precompute any arguments as needed. */
3423 /* Now we are about to start emitting insns that can be deleted
3424 if a libcall is deleted. */
3434 /* Compute the actual size of the argument block required. The variable
3435 and constant sizes must be combined, the size may have to be rounded,
3436 and there may be a minimum required size. When generating a sibcall
3437 pattern, do not round up, since we'll be re-using whatever space our
3438 caller provided. */
3439 unadjusted_args_size
3448 /* The argument block when performing a sibling call is the
3449 incoming argument block. */
3451 {
3454 argblock
3456 else
3457 argblock
3462 }
3464 /* If we have no actual push instructions, or shouldn't use them,
3465 make space for all args right now. */
3467 {
3469 {
3474 /* stack_arg_under_construction says whether a stack arg is
3475 being constructed at the old stack level. Pushing the stack
3476 gets a clean outgoing argument block. */
3479 }
3483 }
3484 else
3485 {
3486 /* Note that we must go through the motions of allocating an argument
3487 block even if the size is zero because we may be storing args
3488 in the area reserved for register arguments, which may be part of
3489 the stack frame. */
3493 /* Store the maximum argument space used. It will be pushed by
3494 the prologue (if ACCUMULATE_OUTGOING_ARGS, or stack overflow
3495 checking). */
3501 {
3503 {
3504 /* Since the stack pointer will never be pushed, it is
3505 possible for the evaluation of a parm to clobber
3506 something we have already written to the stack.
3507 Since most function calls on RISC machines do not use
3508 the stack, this is uncommon, but must work correctly.
3510 Therefore, we save any area of the stack that was already
3511 written and that we are using. Here we set up to do this
3512 by making a new stack usage map from the old one. The
3513 actual save will be done by store_one_arg.
3515 Another approach might be to try to reorder the argument
3516 evaluations to avoid this conflicting stack usage. */
3518 /* Since we will be writing into the entire argument area,
3519 the map must be allocated for its entire size, not just
3520 the part that is the responsibility of the caller. */
3525 highest_outgoing_arg_in_use
3527 else
3528 highest_outgoing_arg_in_use
3537 initial_highest_arg_in_use);
3541 (highest_outgoing_arg_in_use
3545 /* The address of the outgoing argument list must not be
3546 copied to a register here, because argblock would be left
3547 pointing to the wrong place after the call to
3548 allocate_dynamic_stack_space below. */
3551 }
3552 else
3553 {
3555 {
3556 /* Try to reuse some or all of the pending_stack_adjust
3557 to get this space. */
3558 needed
3559 = (combine_pending_stack_adjustment_and_call
3562 preferred_unit_stack_boundary));
3564 /* combine_pending_stack_adjustment_and_call computes
3565 an adjustment before the arguments are allocated.
3566 Account for them and see whether or not the stack
3567 needs to go up or down. */
3571 {
3572 /* We're releasing stack space. */
3573 /* ??? We can avoid any adjustment at all if we're
3574 already aligned. FIXME. */
3578 }
3579 else
3580 /* We need to allocate space. We'll do that in
3581 push_block below. */
3583 }
3585 /* Special case this because overhead of `push_block' in
3586 this case is non-trivial. */
3589 else
3590 {
3594 }
3596 /* We only really need to call `copy_to_reg' in the case
3597 where push insns are going to be used to pass ARGBLOCK
3598 to a function call in ARGS. In that case, the stack
3599 pointer changes value from the allocation point to the
3600 call point, and hence the value of
3601 VIRTUAL_OUTGOING_ARGS_RTX changes as well. But might
3602 as well always do it. */
3604 }
3605 }
3606 }
3609 {
3610 /* The save/restore code in store_one_arg handles all
3611 cases except one: a constructor call (including a C
3612 function returning a BLKmode struct) to initialize
3613 an argument. */
3615 {
3616 rtx push_size
3622 {
3627 /* stack_arg_under_construction says whether a stack
3628 arg is being constructed at the old stack level.
3629 Pushing the stack gets a clean outgoing argument
3630 block. */
3631 old_stack_arg_under_construction
3634 /* Make a new map for the new argument list. */
3639 }
3640 /* We can pass TRUE as the 4th argument because we just
3641 saved the stack pointer and will restore it right after
3642 the call. */
3645 }
3647 /* If argument evaluation might modify the stack pointer,
3648 copy the address of the argument list to a register. */
3651 {
3654 }
3655 }
3659 /* Stack is properly aligned, pops can't safely be deferred during
3660 the evaluation of the arguments. */
3661 NO_DEFER_POP;
3663 /* Precompute all register parameters. It isn't safe to compute
3664 anything once we have started filling any specific hard regs.
3665 TLS symbols sometimes need a call to resolve. Precompute
3666 register parameters before any stack pointer manipulation
3667 to avoid unaligned stack in the called function. */
3670 OK_DEFER_POP;
3672 /* Perform stack alignment before the first push (the last arg). */
3676 {
3677 /* When the stack adjustment is pending, we get better code
3678 by combining the adjustments. */
3681 {
3682 pending_stack_adjust
3683 = (combine_pending_stack_adjustment_and_call
3686 preferred_unit_stack_boundary));
3688 }
3692 }
3693 /* Now that the stack is properly aligned, pops can't safely
3694 be deferred during the evaluation of the arguments. */
3695 NO_DEFER_POP;
3697 /* Record the maximum pushed stack space size. We need to delay
3698 doing it this far to take into account the optimization done
3699 by combine_pending_stack_adjustment_and_call. */
3701 && !ACCUMULATE_OUTGOING_ARGS
3702 && pass
3704 {
3708 }
3714 else
3717 #ifdef REG_PARM_STACK_SPACE
3718 /* Save the fixed argument area if it's part of the caller's frame and
3719 is clobbered by argument setup for this call. */
3723 #endif
3725 /* Now store (and compute if necessary) all non-register parms.
3726 These come before register parms, since they can require block-moves,
3727 which could clobber the registers used for register parms.
3728 Parms which have partial registers are not stored here,
3729 but we do preallocate space here if they want that. */
3732 {
3733 /* Delay bounds until all other args are stored. */
3737 {
3740 /* We don't allow passing huge (> 2^30 B) arguments
3741 by value. It would cause an overflow later on. */
3744 {
3747 }
3751 reg_parm_stack_space)
3756 }
3759 call_fusage
3762 call_fusage);
3763 }
3765 /* If we have a parm that is passed in registers but not in memory
3766 and whose alignment does not permit a direct copy into registers,
3767 make a group of pseudos that correspond to each register that we
3768 will later fill. */
3772 /* Now store any partially-in-registers parm.
3773 This is the last place a block-move can happen. */
3777 {
3780 /* On targets with weird calling conventions (e.g. PA) it's
3781 hard to ensure that all cases of argument overlap between
3782 stack and registers work. Play it safe and bail out. */
3784 {
3787 }
3791 reg_parm_stack_space)
3796 }
3801 {
3804 }
3808 /* Figure out the register where the value, if any, will come back. */
3813 {
3815 {
3822 }
3823 else
3824 {
3829 fndecl,
3831 }
3833 /* If VALREG is a PARALLEL whose first member has a zero
3834 offset, use that. This is for targets such as m68k that
3835 return the same value in multiple places. */
3837 {
3844 }
3845 }
3847 /* Store all bounds not passed in registers. */
3849 {
3854 ? NULL
3856 }
3858 /* If register arguments require space on the stack and stack space
3859 was not preallocated, allocate stack space here for arguments
3860 passed in registers. */
3862 && !ACCUMULATE_OUTGOING_ARGS
3866 /* Pass the function the address in which to return a
3867 structure value. */
3869 {
3870 structure_value_addr
3875 NULL_RTX)));
3879 }
3889 /* Save a pointer to the last insn before the call, so that we can
3890 later safely search backwards to find the CALL_INSN. */
3893 /* Set up next argument register. For sibling calls on machines
3894 with register windows this should be the incoming register. */
3897 VOIDmode,
3898 void_type_node,
3900 else
3906 {
3912 && valreg
3915 call_fusage
3918 call_fusage);
3919 }
3920 /* All arguments and registers used for the call must be set up by
3921 now! */
3923 /* Stack must be properly aligned now. */
3927 /* Generate the actual call instruction. */
3934 {
3938 {
3942 }
3945 }
3947 /* If the call setup or the call itself overlaps with anything
3948 of the argument setup we probably clobbered our call address.
3949 In that case we can't do sibcalls. */
3954 /* If a non-BLKmode value is returned at the most significant end
3955 of a register, shift the register right by the appropriate amount
3956 and update VALREG accordingly. BLKmode values are handled by the
3957 group load/store machinery below. */
3959 && !pcc_struct_value
3964 {
3968 }
3971 {
3975 /* The return value from a malloc-like function is a pointer. */
3981 /* The return value from a malloc-like function can not alias
3982 anything else. */
3986 /* Write out the sequence. */
3991 }
3993 /* For calls to `setjmp', etc., inform
3994 function.c:setjmp_warnings that it should complain if
3995 nonvolatile values are live. For functions that cannot
3996 return, inform flow that control does not fall through. */
3999 {
4000 /* The barrier must be emitted
4001 immediately after the CALL_INSN. Some ports emit more
4002 than just a CALL_INSN above, so we must search for it here. */
4006 {
4008 /* There was no CALL_INSN? */
4010 }
4014 /* Stack adjustments after a noreturn call are dead code.
4015 However when NO_DEFER_POP is in effect, we must preserve
4016 stack_pointer_delta. */
4018 {
4021 }
4022 }
4024 /* If value type not void, return an rtx for the value. */
4030 {
4032 {
4033 target
4036 structure_value_addr));
4038 }
4039 }
4041 {
4042 /* This is the special C++ case where we need to
4043 know what the true target was. We take care to
4044 never use this value more than once in one expression. */
4048 }
4049 /* Handle calls that return values in multiple non-contiguous locations.
4050 The Irix 6 ABI has examples of this. */
4052 {
4056 ;
4058 /* Handle the result of a emit_group_move_into_temps
4059 call in the previous pass. */
4061 else
4064 }
4068 {
4071 /* We have to copy a return value in a CLASS_LIKELY_SPILLED hard
4072 reg to a plain register. */
4076 /* If TARGET is a MEM in the argument area, and we have
4077 saved part of the argument area, then we can't store
4078 directly into TARGET as it may get overwritten when we
4079 restore the argument save area below. Don't work too
4080 hard though and simply force TARGET to a register if it
4081 is a MEM; the optimizer is quite likely to sort it out. */
4085 {
4088 }
4092 else
4093 {
4094 /* TARGET and VALREG cannot be equal at this point
4095 because the latter would not have
4096 REG_FUNCTION_VALUE_P true, while the former would if
4097 it were referring to the same register.
4099 If they refer to the same register, this move will be
4100 a no-op, except when function inlining is being
4101 done. */
4104 /* If we are setting a MEM, this code must be executed.
4105 Since it is emitted after the call insn, sibcall
4106 optimization cannot be performed in that case. */
4109 }
4110 }
4111 else
4114 /* If we promoted this return value, make the proper SUBREG.
4115 TARGET might be const0_rtx here, so be careful. */
4119 {
4123 machine_mode pmode;
4125 /* Ensure we promote as expected, and get the new unsignedness. */
4133 {
4140 }
4145 }
4147 /* If size of args is variable or this was a constructor call for a stack
4148 argument, restore saved stack-pointer value. */
4151 {
4165 }
4167 {
4168 #ifdef REG_PARM_STACK_SPACE
4172 #endif
4174 /* If we saved any argument areas, restore them. */
4177 {
4179 rtx stack_area
4186 else
4189 BLOCK_OP_CALL_PARM);
4190 }
4194 }
4196 /* If this was alloca, record the new stack level. */
4200 /* Free up storage we no longer need. */
4210 {
4213 /* Restore the pending stack adjustment now that we have
4214 finished generating the sibling call sequence. */
4218 /* Prepare arg structure for next iteration. */
4220 {
4224 }
4229 }
4230 else
4231 {
4234 /* Verify that we've deallocated all the stack we used. */
4236 || (old_stack_allocated
4238 }
4240 /* If something prevents making this a sibling call,
4241 zero out the sequence. */
4244 else
4246 }
4248 /* If tail call production succeeded, we need to remove REG_EQUIV notes on
4249 arguments too, as argument area is now clobbered by the call. */
4251 {
4254 }
4255 else
4256 {
4259 /* Ideally we'd emit a message for all of the ways that it could
4260 have failed. */
4262 }
4264 currently_expanding_call--;
4269 /* Join result with returned bounds so caller may use them if needed. */
4273 }
4275 /* A sibling call sequence invalidates any REG_EQUIV notes made for
4276 this function's incoming arguments.
4278 At the start of RTL generation we know the only REG_EQUIV notes
4279 in the rtl chain are those for incoming arguments, so we can look
4280 for REG_EQUIV notes between the start of the function and the
4281 NOTE_INSN_FUNCTION_BEG.
4283 This is (slight) overkill. We could keep track of the highest
4284 argument we clobber and be more selective in removing notes, but it
4285 does not seem to be worth the effort. */
4287 void
4289 {
4293 {
4294 rtx note;
4296 /* There are never REG_EQUIV notes for the incoming arguments
4297 after the NOTE_INSN_FUNCTION_BEG note, so stop if we see it. */
4307 }
4308 }
4310 /* Traverse a list of TYPES and expand all complex types into their
4311 components. */
4312 static tree
4314 {
4315 tree p;
4317 /* Before allocating memory, check for the common case of no complex. */
4319 {
4324 }
4327 found:
4331 {
4336 {
4339 /* Rewrite complex type with component type. */
4343 /* Add another component type for the imaginary part. */
4348 /* Skip the newly created node. */
4350 }
4351 }
4354 }
4355 \f
4356 /* Output a library call to function ORGFUN (a SYMBOL_REF rtx)
4357 for a value of mode OUTMODE,
4358 with NARGS different arguments, passed as ARGS.
4359 Store the return value if RETVAL is nonzero: store it in VALUE if
4360 VALUE is nonnull, otherwise pick a convenient location. In either
4361 case return the location of the stored value.
4363 FN_TYPE should be LCT_NORMAL for `normal' calls, LCT_CONST for
4364 `const' calls, LCT_PURE for `pure' calls, or another LCT_ value for
4365 other types of library calls. */
4367 rtx
4371 {
4372 /* Total size in bytes of all the stack-parms scanned so far. */
4374 /* Size of arguments before any adjustments (such as rounding). */
4377 rtx fun;
4378 /* Todo, choose the correct decl type of orgfun. Sadly this information
4379 isn't present here, so we default to native calling abi here. */
4384 CUMULATIVE_ARGS args_so_far_v;
4385 cumulative_args_t args_so_far;
4386 struct arg
4387 {
4388 rtx value;
4389 machine_mode mode;
4390 rtx reg;
4393 rtx save_area;
4394 };
4399 rtx valreg;
4409 #ifdef REG_PARM_STACK_SPACE
4410 /* Define the boundary of the register parm stack space that needs to be
4411 save, if any. */
4414 #endif
4416 /* Size of the stack reserved for parameter registers. */
4423 #ifdef REG_PARM_STACK_SPACE
4425 #endif
4427 /* By default, library functions cannot throw. */
4431 {
4449 }
4452 /* Ensure current function's preferred stack boundary is at least
4453 what we need. */
4457 /* If this kind of value comes back in memory,
4458 decide where in memory it should come back. */
4460 {
4463 {
4464 #ifdef PCC_STATIC_STRUCT_RETURN
4465 rtx pointer_reg
4475 else
4477 #endif
4478 /* This call returns a big structure. */
4480 }
4481 }
4482 else
4485 /* ??? Unfinished: must pass the memory address as an argument. */
4487 /* Copy all the libcall-arguments out of the varargs data
4488 and into a vector ARGVEC.
4490 Compute how to pass each argument. We only support a very small subset
4491 of the full argument passing conventions to limit complexity here since
4492 library functions shouldn't have many args. */
4497 #ifdef INIT_CUMULATIVE_LIBCALL_ARGS
4499 #else
4501 #endif
4511 /* If there's a structure value address to be passed,
4512 either pass it in the special place, or pass it as an extra argument. */
4514 {
4517 nargs++;
4519 /* Make sure it is a reasonable operand for a move or push insn. */
4535 #ifdef STACK_PARMS_IN_REG_PARM_AREA
4537 #else
4539 #endif
4549 count++;
4550 }
4553 {
4558 /* We cannot convert the arg value to the mode the library wants here;
4559 must do it earlier where we know the signedness of the arg. */
4563 /* Make sure it is a reasonable operand for a move or push insn. */
4569 {
4570 rtx slot;
4571 int must_copy
4574 /* If this was a CONST function, it is now PURE since it now
4575 reads memory. */
4577 {
4580 }
4583 {
4588 }
4589 else
4590 {
4594 }
4598 call_fusage);
4602 slot),
4603 call_fusage);
4607 }
4621 {
4623 #ifdef STACK_PARMS_IN_REG_PARM_AREA
4625 #else
4627 #endif
4632 }
4633 #ifdef BLOCK_REG_PADDING
4634 else
4635 /* The argument is passed entirely in registers. See at which
4636 end it should be padded. */
4640 #endif
4643 }
4645 /* If this machine requires an external definition for library
4646 functions, write one out. */
4651 + stack_pointer_delta
4653 / STACK_BYTES
4658 reg_parm_stack_space);
4667 {
4671 }
4674 {
4675 /* Since the stack pointer will never be pushed, it is possible for
4676 the evaluation of a parm to clobber something we have already
4677 written to the stack. Since most function calls on RISC machines
4678 do not use the stack, this is uncommon, but must work correctly.
4680 Therefore, we save any area of the stack that was already written
4681 and that we are using. Here we set up to do this by making a new
4682 stack usage map from the old one.
4684 Another approach might be to try to reorder the argument
4685 evaluations to avoid this conflicting stack usage. */
4689 /* Since we will be writing into the entire argument area, the
4690 map must be allocated for its entire size, not just the part that
4691 is the responsibility of the caller. */
4698 else
4706 initial_highest_arg_in_use);
4713 /* We must be careful to use virtual regs before they're instantiated,
4714 and real regs afterwards. Loop optimization, for example, can create
4715 new libcalls after we've instantiated the virtual regs, and if we
4716 use virtuals anyway, they won't match the rtl patterns. */
4720 STACK_POINTER_OFFSET);
4721 else
4723 }
4724 else
4725 {
4728 }
4730 /* We push args individually in reverse order, perform stack alignment
4731 before the first push (the last arg). */
4738 #ifdef REG_PARM_STACK_SPACE
4740 {
4741 /* The argument list is the property of the called routine and it
4742 may clobber it. If the fixed area has been used for previous
4743 parameters, we must save and restore it. */
4746 }
4747 #endif
4749 /* When expanding a normal call, args are stored in push order,
4750 which is the reverse of what we have here. */
4754 {
4757 }
4761 /* Push the args that need to be pushed. */
4765 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
4766 are to be pushed. */
4768 {
4777 {
4778 rtx use;
4781 {
4782 /* If this is being stored into a pre-allocated, fixed-size,
4783 stack area, save any previous data at that location. */
4786 {
4787 /* stack_slot is negative, but we want to index stack_usage_map
4788 with positive values. */
4791 }
4792 else
4793 {
4796 }
4799 /* Don't worry about things in the fixed argument area;
4800 it has already been saved. */
4804 i++;
4807 {
4808 /* We need to make a save area. */
4809 unsigned int size
4811 machine_mode save_mode
4813 rtx adr
4816 rtx stack_area
4820 {
4824 );
4828 stack_area,
4830 BLOCK_OP_CALL_PARM);
4831 }
4832 else
4833 {
4837 }
4838 }
4839 }
4844 reg_parm_stack_space,
4847 /* Now mark the segment we just used. */
4852 NO_DEFER_POP;
4854 /* Indicate argument access so that alias.c knows that these
4855 values are live. */
4861 else
4862 {
4863 /* When arguments are pushed, trying to tell alias.c where
4864 exactly this argument is won't work, because the
4865 auto-increment causes confusion. So we merely indicate
4866 that we access something with a known mode somewhere on
4867 the stack. */
4871 }
4875 }
4876 }
4882 /* Now load any reg parms into their regs. */
4884 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
4885 are to be pushed. */
4887 {
4892 #ifdef BLOCK_REG_PADDING
4894 #endif
4896 /* Handle calls that pass values in multiple non-contiguous
4897 locations. The PA64 has examples of this for library calls. */
4901 {
4903 #ifdef BLOCK_REG_PADDING
4906 /* Copied from load_register_parameters. */
4908 /* Handle case where we have a value that needs shifting
4909 up to the msb. eg. a QImode value and we're padding
4910 upward on a BYTES_BIG_ENDIAN machine. */
4914 {
4915 rtx x;
4918 /* Assigning REG here rather than a temp makes CALL_FUSAGE
4919 report the whole reg as used. Strictly speaking, the
4920 call only uses SIZE bytes at the msb end, but it doesn't
4921 seem worth generating rtl to say that. */
4926 }
4927 #endif
4928 }
4930 NO_DEFER_POP;
4931 }
4933 /* Any regs containing parms remain in use through the call. */
4935 {
4940 {
4943 {
4948 }
4949 else
4951 }
4952 }
4954 /* Pass the function the address in which to return a structure value. */
4956 {
4960 NULL_RTX)));
4963 }
4965 /* Don't allow popping to be deferred, since then
4966 cse'ing of library calls could delete a call and leave the pop. */
4967 NO_DEFER_POP;
4971 /* Stack must be properly aligned now. */
4977 /* We pass the old value of inhibit_defer_pop + 1 to emit_call_1, which
4978 will set inhibit_defer_pop to that value. */
4979 /* The return type is needed to decide how many bytes the function pops.
4980 Signedness plays no role in that, so for simplicity, we pretend it's
4981 always signed. We also assume that the list of arguments passed has
4982 no impact, so we pretend it is unknown. */
4988 struct_value_size,
4991 valreg,
4995 {
5000 }
5002 /* Right-shift returned value if necessary. */
5006 {
5009 }
5013 /* For calls to `setjmp', etc., inform function.c:setjmp_warnings
5014 that it should complain if nonvolatile values are live. For
5015 functions that cannot return, inform flow that control does not
5016 fall through. */
5018 {
5019 /* The barrier note must be emitted
5020 immediately after the CALL_INSN. Some ports emit more than
5021 just a CALL_INSN above, so we must search for it here. */
5024 {
5026 /* There was no CALL_INSN? */
5028 }
5031 }
5033 /* Consider that "regular" libcalls, i.e. all of them except for LCT_THROW
5034 and LCT_RETURNS_TWICE, cannot perform non-local gotos. */
5036 {
5039 {
5041 /* There was no CALL_INSN? */
5043 }
5046 }
5048 /* Now restore inhibit_defer_pop to its actual original value. */
5049 OK_DEFER_POP;
5053 /* Copy the value to the right place. */
5055 {
5057 {
5062 }
5064 {
5068 }
5069 else
5070 {
5071 /* Convert to the proper mode if a promotion has been active. */
5073 {
5080 }
5084 else
5086 }
5087 }
5090 {
5091 #ifdef REG_PARM_STACK_SPACE
5095 #endif
5097 /* If we saved any argument areas, restore them. */
5100 {
5109 validize_mem
5112 BLOCK_OP_CALL_PARM);
5113 else
5115 }
5119 }
5125 }
5126 \f
5128 /* Store pointer bounds argument ARG into Bounds Table entry
5129 associated with PARM. */
5130 static void
5132 {
5135 /* We may pass bounds not associated with any pointer. */
5137 {
5141 }
5142 /* Find pointer associated with bounds and where it is
5143 passed. */
5144 else
5145 {
5147 {
5151 }
5153 {
5161 else
5162 {
5165 }
5166 }
5167 else
5168 {
5177 else
5179 }
5180 }
5182 /* Expand bounds. */
5187 }
5189 /* Store a single argument for a function call
5190 into the register or memory area where it must be passed.
5191 *ARG describes the argument value and where to pass it.
5193 ARGBLOCK is the address of the stack-block for all the arguments,
5194 or 0 on a machine where arguments are pushed individually.
5196 MAY_BE_ALLOCA nonzero says this could be a call to `alloca'
5197 so must be careful about how the stack is used.
5199 VARIABLE_SIZE nonzero says that this was a variable-sized outgoing
5200 argument stack. This is used if ACCUMULATE_OUTGOING_ARGS to indicate
5201 that we need not worry about saving and restoring the stack.
5203 FNDECL is the declaration of the function we are calling.
5205 Return nonzero if this arg should cause sibcall failure,
5206 zero otherwise. */
5208 static int
5211 {
5222 /* Push a new temporary level for any temporaries we make for
5223 this argument. */
5227 {
5228 /* If this is being stored into a pre-allocated, fixed-size, stack area,
5229 save any previous data at that location. */
5231 {
5233 {
5234 /* stack_slot is negative, but we want to index stack_usage_map
5235 with positive values. */
5238 else
5242 }
5243 else
5244 {
5247 else
5251 }
5254 /* Don't worry about things in the fixed argument area;
5255 it has already been saved. */
5259 i++;
5262 {
5263 /* We need to make a save area. */
5265 machine_mode save_mode
5271 {
5272 arg->save_area
5276 stack_area,
5278 BLOCK_OP_CALL_PARM);
5279 }
5280 else
5281 {
5284 }
5285 }
5286 }
5287 }
5289 /* If this isn't going to be placed on both the stack and in registers,
5290 set up the register and number of words. */
5292 {
5295 else
5298 }
5300 /* Being passed entirely in a register. We shouldn't be called in
5301 this case. */
5304 /* If this arg needs special alignment, don't load the registers
5305 here. */
5309 /* If this is being passed partially in a register, we can't evaluate
5310 it directly into its stack slot. Otherwise, we can. */
5312 {
5313 /* stack_arg_under_construction is nonzero if a function argument is
5314 being evaluated directly into the outgoing argument list and
5315 expand_call must take special action to preserve the argument list
5316 if it is called recursively.
5318 For scalar function arguments stack_usage_map is sufficient to
5319 determine which stack slots must be saved and restored. Scalar
5320 arguments in general have pass_on_stack == 0.
5322 If this argument is initialized by a function which takes the
5323 address of the argument (a C++ constructor or a C function
5324 returning a BLKmode structure), then stack_usage_map is
5325 insufficient and expand_call must push the stack around the
5326 function call. Such arguments have pass_on_stack == 1.
5328 Note that it is always safe to set stack_arg_under_construction,
5329 but this generates suboptimal code if set when not needed. */
5332 stack_arg_under_construction++;
5335 (partial
5340 /* If we are promoting object (or for any other reason) the mode
5341 doesn't agree, convert the mode. */
5348 stack_arg_under_construction--;
5349 }
5351 /* Check for overlap with already clobbered argument area. */
5358 /* Don't allow anything left on stack from computation
5359 of argument to alloca. */
5364 /* If the value is already in the stack slot, we are done. */
5365 ;
5367 {
5371 /* Argument is a scalar, not entirely passed in registers.
5372 (If part is passed in registers, arg->partial says how much
5373 and emit_push_insn will take care of putting it there.)
5375 Push it, and if its size is less than the
5376 amount of space allocated to it,
5377 also bump stack pointer by the additional space.
5378 Note that in C the default argument promotions
5379 will prevent such mismatches. */
5382 /* Compute how much space the push instruction will push.
5383 On many machines, pushing a byte will advance the stack
5384 pointer by a halfword. */
5385 #ifdef PUSH_ROUNDING
5387 #endif
5390 /* Compute how much space the argument should get:
5391 round up to a multiple of the alignment for arguments. */
5398 /* Compute the alignment of the pushed argument. */
5402 {
5405 {
5408 }
5409 }
5411 /* This isn't already where we want it on the stack, so put it there.
5412 This can either be done with push or copy insns. */
5419 /* Unless this is a partially-in-register argument, the argument is now
5420 in the stack. */
5423 }
5424 else
5425 {
5426 /* BLKmode, at least partly to be pushed. */
5430 rtx size_rtx;
5432 /* Pushing a nonscalar.
5433 If part is passed in registers, PARTIAL says how much
5434 and emit_push_insn will take care of putting it there. */
5436 /* Round its size up to a multiple
5437 of the allocation unit for arguments. */
5440 {
5443 }
5444 else
5445 {
5446 /* PUSH_ROUNDING has no effect on us, because emit_push_insn
5447 for BLKmode is careful to avoid it. */
5453 EXPAND_NORMAL);
5454 }
5458 /* When an argument is padded down, the block is aligned to
5459 PARM_BOUNDARY, but the actual argument isn't. */
5462 {
5466 {
5469 }
5470 }
5473 {
5474 /* emit_push_insn might not work properly if arg->value and
5475 argblock + arg->locate.offset areas overlap. */
5484 {
5488 /* arg.locate doesn't contain the pretend_args_size offset,
5489 it's part of argblock. Ensure we don't count it in I. */
5492 else
5495 /* expand_call should ensure this. */
5501 {
5504 }
5506 {
5507 /* Use arg->locate.size.constant instead of size_rtx
5508 because we only care about the part of the argument
5509 on the stack. */
5513 }
5514 else
5515 {
5516 /* Even though they appear to be at the same location,
5517 if part of the outgoing argument is in registers,
5518 they aren't really at the same location. Check for
5519 this by making sure that the incoming size is the
5520 same as the outgoing size. */
5523 }
5524 }
5525 }
5532 /* Unless this is a partially-in-register argument, the argument is now
5533 in the stack.
5535 ??? Unlike the case above, in which we want the actual
5536 address of the data, so that we can load it directly into a
5537 register, here we want the address of the stack slot, so that
5538 it's properly aligned for word-by-word copying or something
5539 like that. It's not clear that this is always correct. */
5542 }
5545 {
5547 arg->parallel_value
5550 }
5552 /* Mark all slots this store used. */
5558 /* Once we have pushed something, pops can't safely
5559 be deferred during the rest of the arguments. */
5560 NO_DEFER_POP;
5562 /* Free any temporary slots made in processing this argument. */
5566 }
5568 /* Nonzero if we do not know how to pass TYPE solely in registers. */
5570 bool
5572 const_tree type)
5573 {
5577 /* If the type has variable size... */
5581 /* If the type is marked as addressable (it is required
5582 to be constructed into the stack)... */
5587 }
5589 /* Another version of the TARGET_MUST_PASS_IN_STACK hook. This one
5590 takes trailing padding of a structure into account. */
5591 /* ??? Should be able to merge these two by examining BLOCK_REG_PADDING. */
5593 bool
5595 {
5599 /* If the type has variable size... */
5603 /* If the type is marked as addressable (it is required
5604 to be constructed into the stack)... */
5608 /* If the padding and mode of the type is such that a copy into
5609 a register would put it into the wrong part of the register. */
5617 }
5619 /* Tell the garbage collector about GTY markers in this source file. */