| blob | c92e35ea5a8d77f8bebfcaa5112c127b629c26a0 |
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/>. */
56 /* Like PREFERRED_STACK_BOUNDARY but in units of bytes, not bits. */
57 #define STACK_BYTES (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT)
59 /* Data structure and subroutines used within expand_call. */
61 struct arg_data
62 {
63 /* Tree node for this argument. */
64 tree tree_value;
65 /* Mode for value; TYPE_MODE unless promoted. */
66 machine_mode mode;
67 /* Current RTL value for argument, or 0 if it isn't precomputed. */
68 rtx value;
69 /* Initially-compute RTL value for argument; only for const functions. */
70 rtx initial_value;
71 /* Register to pass this argument in, 0 if passed on stack, or an
72 PARALLEL if the arg is to be copied into multiple non-contiguous
73 registers. */
74 rtx reg;
75 /* Register to pass this argument in when generating tail call sequence.
76 This is not the same register as for normal calls on machines with
77 register windows. */
78 rtx tail_call_reg;
79 /* If REG is a PARALLEL, this is a copy of VALUE pulled into the correct
80 form for emit_group_move. */
81 rtx parallel_value;
82 /* If value is passed in neither reg nor stack, this field holds a number
83 of a special slot to be used. */
84 rtx special_slot;
85 /* For pointer bounds hold an index of parm bounds are bound to. -1 if
86 there is no such pointer. */
88 /* If pointer_arg refers a structure, then pointer_offset holds an offset
89 of a pointer in this structure. */
91 /* If REG was promoted from the actual mode of the argument expression,
92 indicates whether the promotion is sign- or zero-extended. */
94 /* Number of bytes to put in registers. 0 means put the whole arg
95 in registers. Also 0 if not passed in registers. */
97 /* Nonzero if argument must be passed on stack.
98 Note that some arguments may be passed on the stack
99 even though pass_on_stack is zero, just because FUNCTION_ARG says so.
100 pass_on_stack identifies arguments that *cannot* go in registers. */
102 /* Some fields packaged up for locate_and_pad_parm. */
104 /* Location on the stack at which parameter should be stored. The store
105 has already been done if STACK == VALUE. */
106 rtx stack;
107 /* Location on the stack of the start of this argument slot. This can
108 differ from STACK if this arg pads downward. This location is known
109 to be aligned to TARGET_FUNCTION_ARG_BOUNDARY. */
110 rtx stack_slot;
111 /* Place that this stack area has been saved, if needed. */
112 rtx save_area;
113 /* If an argument's alignment does not permit direct copying into registers,
114 copy in smaller-sized pieces into pseudos. These are stored in a
115 block pointed to by this field. The next field says how many
116 word-sized pseudos we made. */
119 };
121 /* A vector of one char per byte of stack space. A byte if nonzero if
122 the corresponding stack location has been used.
123 This vector is used to prevent a function call within an argument from
124 clobbering any stack already set up. */
127 /* Size of STACK_USAGE_MAP. */
130 /* A bitmap of virtual-incoming stack space. Bit is set if the corresponding
131 stack location's tail call argument has been already stored into the stack.
132 This bitmap is used to prevent sibling call optimization if function tries
133 to use parent's incoming argument slots when they have been already
134 overwritten with tail call arguments. */
137 /* stack_arg_under_construction is nonzero when an argument may be
138 initialized with a constructor call (including a C function that
139 returns a BLKmode struct) and expand_call must take special action
140 to make sure the object being constructed does not overlap the
141 argument list for the constructor call. */
146 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. */
829 {
836 }
839 }
841 {
849 }
850 else
854 {
858 }
861 }
863 /* Detect flags from a CALL_EXPR. */
865 int
867 {
875 else
876 {
880 else
884 }
887 }
889 /* Return true if TYPE should be passed by invisible reference. */
891 bool
894 {
896 {
897 /* If this type contains non-trivial constructors, then it is
898 forbidden for the middle-end to create any new copies. */
902 /* GCC post 3.4 passes *all* variable sized types by reference. */
906 /* If a record type should be passed the same as its first (and only)
907 member, use the type and mode of that member. */
909 {
912 }
913 }
917 }
919 /* Return true if TYPE, which is passed by reference, should be callee
920 copied instead of caller copied. */
922 bool
925 {
929 named_arg);
930 }
933 /* Precompute all register parameters as described by ARGS, storing values
934 into fields within the ARGS array.
936 NUM_ACTUALS indicates the total number elements in the ARGS array.
938 Set REG_PARM_SEEN if we encounter a register parameter. */
940 static void
943 {
950 {
954 {
959 }
961 /* If we are to promote the function arg to a wider mode,
962 do it now. */
970 /* If the value is a non-legitimate constant, force it into a
971 pseudo now. TLS symbols sometimes need a call to resolve. */
976 /* If we're going to have to load the value by parts, pull the
977 parts into pseudos. The part extraction process can involve
978 non-trivial computation. */
980 {
985 }
987 /* If the value is expensive, and we are inside an appropriately
988 short loop, put the value into a pseudo and then put the pseudo
989 into the hard reg.
991 For small register classes, also do this if this call uses
992 register parameters. This is to avoid reload conflicts while
993 loading the parameters registers. */
1002 && ((*reg_parm_seen
1006 }
1007 }
1009 #ifdef REG_PARM_STACK_SPACE
1011 /* The argument list is the property of the called routine and it
1012 may clobber it. If the fixed area has been used for previous
1013 parameters, we must save and restore it. */
1015 static rtx
1016 save_fixed_argument_area (int reg_parm_stack_space, rtx argblock, int *low_to_save, int *high_to_save)
1017 {
1021 /* Compute the boundary of the area that needs to be saved, if any. */
1031 {
1033 machine_mode save_mode;
1035 rtx addr;
1036 rtx stack_area;
1037 rtx save_area;
1040 ;
1048 /* If we don't have the required alignment, must do this
1049 in BLKmode. */
1056 else
1064 {
1068 }
1069 else
1070 {
1073 }
1076 }
1079 }
1081 static void
1083 {
1090 else
1099 else
1102 BLOCK_OP_CALL_PARM);
1103 }
1106 /* If any elements in ARGS refer to parameters that are to be passed in
1107 registers, but not in memory, and whose alignment does not permit a
1108 direct copy into registers. Copy the values into a group of pseudos
1109 which we will later copy into the appropriate hard registers.
1111 Pseudos for each unaligned argument will be stored into the array
1112 args[argnum].aligned_regs. The caller is responsible for deallocating
1113 the aligned_regs array if it is nonzero. */
1115 static void
1117 {
1127 {
1132 {
1135 }
1136 else
1137 {
1140 }
1144 /* Structures smaller than a word are normally aligned to the
1145 least significant byte. On a BYTES_BIG_ENDIAN machine,
1146 this means we must skip the empty high order bytes when
1147 calculating the bit offset. */
1149 #ifdef BLOCK_REG_PADDING
1153 #else
1154 && BYTES_BIG_ENDIAN
1155 #endif
1156 )
1160 {
1169 /* There is no need to restrict this code to loading items
1170 in TYPE_ALIGN sized hunks. The bitfield instructions can
1171 load up entire word sized registers efficiently.
1173 ??? This may not be needed anymore.
1174 We use to emit a clobber here but that doesn't let later
1175 passes optimize the instructions we emit. By storing 0 into
1176 the register later passes know the first AND to zero out the
1177 bitfield being set in the register is unnecessary. The store
1178 of 0 will be deleted as will at least the first AND. */
1185 }
1186 }
1187 }
1189 /* The limit set by -Walloc-larger-than=. */
1192 /* Initialize ALLOC_OBJECT_SIZE_LIMIT based on the -Walloc-size-larger-than=
1193 setting if the option is specified, or to the maximum object size if it
1194 is not. Return the initialized value. */
1196 static tree
1198 {
1200 {
1204 {
1208 unsigned HOST_WIDE_INT limit
1212 {
1214 {
1215 /* Numeric option arguments are at most INT_MAX. Make it
1216 possible to specify a larger value by accepting common
1217 suffixes. */
1242 else
1244 }
1247 alloc_object_size_limit
1249 }
1250 }
1251 }
1253 }
1255 /* Return true when EXP's range can be determined and set RANGE[] to it
1256 after adjusting it if necessary to make EXP a valid size argument to
1257 an allocation function declared with attribute alloc_size (whose
1258 argument may be signed), or to a string manipulation function like
1259 memset. */
1261 bool
1263 {
1265 {
1266 /* EXP is a constant. */
1269 }
1272 enum value_range_type range_type
1277 {
1278 /* No range information available. */
1282 }
1292 {
1294 {
1296 {
1297 /* EXP is not in a strictly negative range. That means
1298 it must be in some (not necessarily strictly) positive
1299 range which includes zero. Since in signed to unsigned
1300 conversions negative values end up converted to large
1301 positive values, and otherwise they are not valid sizes,
1302 the resulting range is in both cases [0, TYPE_MAX]. */
1305 }
1307 {
1308 /* EXP is not in a negative-positive range. That means EXP
1309 is either negative, or greater than max. Since negative
1310 sizes are invalid make the range [MAX + 1, TYPE_MAX]. */
1313 }
1314 else
1315 {
1318 }
1319 }
1321 {
1322 /* EXP is unsigned and not in the range [1, MAX]. That means
1323 it's either zero or greater than MAX. Even though 0 would
1324 normally be detected by -Walloc-zero set the range to
1325 [MAX, TYPE_MAX] so that when MAX is greater than the limit
1326 the whole range is diagnosed. */
1329 }
1330 else
1331 {
1334 }
1335 }
1341 }
1343 /* Diagnose a call EXP to function FN decorated with attribute alloc_size
1344 whose argument numbers given by IDX with values given by ARGS exceed
1345 the maximum object size or cause an unsigned oveflow (wrapping) when
1346 multiplied. When ARGS[0] is null the function does nothing. ARGS[1]
1347 may be null for functions like malloc, and non-null for those like
1348 calloc that are decorated with a two-argument attribute alloc_size. */
1350 void
1352 {
1353 /* The range each of the (up to) two arguments is known to be in. */
1356 /* Maximum object size set by -Walloc-size-larger-than= or SIZE_MAX / 2. */
1363 /* Validate each argument individually. */
1365 {
1367 {
1372 {
1376 }
1378 {
1379 /* Avoid issuing -Walloc-zero for allocation functions other
1380 than __builtin_alloca that are declared with attribute
1381 returns_nonnull because there's no portability risk. This
1382 avoids warning for such calls to libiberty's xmalloc and
1383 friends.
1384 Also avoid issuing the warning for calls to function named
1385 "alloca". */
1394 }
1396 {
1397 /* G++ emits calls to ::operator new[](SIZE_MAX) in C++98
1398 mode and with -fno-exceptions as a way to indicate array
1399 size overflow. There's no good way to detect C++98 here
1400 so avoid diagnosing these calls for all C++ modes. */
1409 "%Kargument %i value %qE exceeds "
1412 }
1413 }
1416 {
1417 /* Verify that the argument's range is not negative (including
1418 upper bound of zero). */
1421 {
1426 }
1428 {
1430 "%Kargument %i range [%E, %E] exceeds "
1434 maxobjsize);
1435 }
1436 }
1437 }
1442 /* For a two-argument alloc_size, validate the product of the two
1443 arguments if both of their values or ranges are known. */
1448 {
1449 /* Check for overflow in the product of a function decorated with
1450 attribute alloc_size (X, Y). */
1460 "%Kproduct %<%E * %E%> of arguments %i and %i "
1466 "%Kproduct %<%E * %E%> of arguments %i and %i "
1470 maxobjsize);
1473 {
1474 /* Print the full range of each of the two arguments to make
1475 it clear when it is, in fact, in a range and not constant. */
1482 }
1483 }
1486 {
1492 else
1495 }
1496 }
1498 /* Issue an error if CALL_EXPR was flagged as requiring
1499 tall-call optimization. */
1501 static void
1503 {
1509 }
1511 /* Fill in ARGS_SIZE and ARGS array based on the parameters found in
1512 CALL_EXPR EXP.
1514 NUM_ACTUALS is the total number of parameters.
1516 N_NAMED_ARGS is the total number of named arguments.
1518 STRUCT_VALUE_ADDR_VALUE is the implicit argument for a struct return
1519 value, or null.
1521 FNDECL is the tree code for the target of this call (if known)
1523 ARGS_SO_FAR holds state needed by the target to know where to place
1524 the next argument.
1526 REG_PARM_STACK_SPACE is the number of bytes of stack space reserved
1527 for arguments which are passed in registers.
1529 OLD_STACK_LEVEL is a pointer to an rtx which olds the old stack level
1530 and may be modified by this routine.
1532 OLD_PENDING_ADJ, MUST_PREALLOCATE and FLAGS are pointers to integer
1533 flags which may be modified by this routine.
1535 MAY_TAILCALL is cleared if we encounter an invisible pass-by-reference
1536 that requires allocation of stack space.
1538 CALL_FROM_THUNK_P is true if this call is the jump from a thunk to
1539 the thunked-to function. */
1541 static void
1548 cumulative_args_t args_so_far,
1553 {
1557 /* Count arg position in order args appear. */
1567 /* In this loop, we consider args in the order they are written.
1568 We fill up ARGS from the back. */
1571 {
1573 call_expr_arg_iterator iter;
1574 tree arg;
1578 {
1580 j--;
1582 /* If we pass structure address then we need to
1583 create bounds for it. Since created bounds is
1584 a call statement, we expand it right here to avoid
1585 fixing all other places where it may be expanded. */
1587 {
1594 j--;
1595 }
1596 }
1599 {
1602 /* Remember last param with pointer and associate it
1603 with following pointer bounds. */
1606 {
1611 {
1614 }
1615 }
1619 {
1623 }
1625 {
1626 /* We expect bounds in instrumented calls only.
1627 Otherwise it is a sign we lost flag due to some optimization
1628 and may emit call args incorrectly. */
1631 /* For structures look for the next available pointer. */
1633 {
1640 /* Check we have no more pointers in the structure. */
1643 }
1646 /* Check we covered all pointers in the previous
1647 non bounds arg. */
1650 }
1651 else
1655 && argtype
1658 {
1661 j--;
1663 }
1664 else
1666 j--;
1667 argpos++;
1668 }
1672 }
1676 /* Extract attribute alloc_size and if set, store the indices of
1677 the corresponding arguments in ALLOC_IDX, and then the actual
1678 argument(s) at those indices in ALLOC_ARGS. */
1684 {
1689 }
1691 /* Array for up to the two attribute alloc_size arguments. */
1694 /* I counts args in order (to be) pushed; ARGPOS counts in order written. */
1696 {
1699 machine_mode mode;
1701 /* Replace erroneous argument with constant zero. */
1705 /* If TYPE is a transparent union or record, pass things the way
1706 we would pass the first field of the union or record. We have
1707 already verified that the modes are the same. */
1712 /* Decide where to pass this arg.
1714 args[i].reg is nonzero if all or part is passed in registers.
1716 args[i].partial is nonzero if part but not all is passed in registers,
1717 and the exact value says how many bytes are passed in registers.
1719 args[i].pass_on_stack is nonzero if the argument must at least be
1720 computed on the stack. It may then be loaded back into registers
1721 if args[i].reg is nonzero.
1723 These decisions are driven by the FUNCTION_... macros and must agree
1724 with those made by function.c. */
1726 /* See if this argument should be passed by invisible reference. */
1729 {
1733 callee_copies
1737 /* If we're compiling a thunk, pass through invisible references
1738 instead of making a copy. */
1740 || (callee_copies
1745 {
1746 /* We may have turned the parameter value into an SSA name.
1747 Go back to the original parameter so we can take the
1748 address. */
1750 {
1754 }
1755 /* Argument setup code may have copied the value to register. We
1756 revert that optimization now because the tail call code must
1757 use the original location. */
1767 /* We can't use sibcalls if a callee-copied argument is
1768 stored in the current function's frame. */
1770 {
1773 "a callee-copied argument is"
1774 " stored in the current "
1776 }
1784 }
1785 else
1786 {
1787 /* We make a copy of the object and pass the address to the
1788 function being called. */
1789 rtx copy;
1796 {
1797 /* This is a variable-sized object. Make space on the stack
1798 for it. */
1802 {
1806 }
1808 /* We can pass TRUE as the 4th argument because we just
1809 saved the stack pointer and will restore it right after
1810 the call. */
1817 }
1818 else
1823 /* Just change the const function to pure and then let
1824 the next test clear the pure based on
1825 callee_copies. */
1827 {
1830 }
1840 "argument must be passed"
1842 }
1843 }
1856 {
1859 }
1861 /* If this is a sibling call and the machine has register windows, the
1862 register window has to be unwinded before calling the routine, so
1863 arguments have to go into the incoming registers. */
1868 else
1878 /* If FUNCTION_ARG returned a (parallel [(expr_list (nil) ...) ...]),
1879 it means that we are to pass this arg in the register(s) designated
1880 by the PARALLEL, but also to pass it in the stack. */
1885 /* If this is an addressable type, we must preallocate the stack
1886 since we must evaluate the object into its final location.
1888 If this is to be passed in both registers and the stack, it is simpler
1889 to preallocate. */
1894 /* No stack allocation and padding for bounds. */
1896 ;
1897 /* Compute the stack-size of this argument. */
1902 #ifdef STACK_PARMS_IN_REG_PARM_AREA
1904 #else
1906 #endif
1907 reg_parm_stack_space,
1910 #ifdef BLOCK_REG_PADDING
1911 else
1912 /* The argument is passed entirely in registers. See at which
1913 end it should be padded. */
1917 #endif
1919 /* Update ARGS_SIZE, the total stack space for args so far. */
1925 /* Increment ARGS_SO_FAR, which has info about which arg-registers
1926 have been used, etc. */
1931 /* Store argument values for functions decorated with attribute
1932 alloc_size. */
1937 }
1940 {
1941 /* Check the arguments of functions decorated with attribute
1942 alloc_size. */
1944 }
1945 }
1947 /* Update ARGS_SIZE to contain the total size for the argument block.
1948 Return the original constant component of the argument block's size.
1950 REG_PARM_STACK_SPACE holds the number of bytes of stack space reserved
1951 for arguments passed in registers. */
1953 static int
1956 tree fndecl ATTRIBUTE_UNUSED,
1957 tree fntype ATTRIBUTE_UNUSED,
1959 {
1962 /* For accumulate outgoing args mode we don't need to align, since the frame
1963 will be already aligned. Align to STACK_BOUNDARY in order to prevent
1964 backends from generating misaligned frame sizes. */
1968 /* Compute the actual size of the argument block required. The variable
1969 and constant sizes must be combined, the size may have to be rounded,
1970 and there may be a minimum required size. */
1973 {
1979 {
1980 /* We don't handle this case yet. To handle it correctly we have
1981 to add the delta, round and subtract the delta.
1982 Currently no machine description requires this support. */
1985 }
1988 {
1989 args_size->var
1993 /* The area corresponding to register parameters is not to count in
1994 the size of the block we need. So make the adjustment. */
1996 args_size->var
1999 }
2000 }
2001 else
2002 {
2007 + stack_pointer_delta
2009 / preferred_stack_boundary
2014 reg_parm_stack_space);
2018 }
2020 }
2022 /* Precompute parameters as needed for a function call.
2024 FLAGS is mask of ECF_* constants.
2026 NUM_ACTUALS is the number of arguments.
2028 ARGS is an array containing information for each argument; this
2029 routine fills in the INITIAL_VALUE and VALUE fields for each
2030 precomputed argument. */
2032 static void
2034 {
2037 /* If this is a libcall, then precompute all arguments so that we do not
2038 get extraneous instructions emitted as part of the libcall sequence. */
2040 /* If we preallocated the stack space, and some arguments must be passed
2041 on the stack, then we must precompute any parameter which contains a
2042 function call which will store arguments on the stack.
2043 Otherwise, evaluating the parameter may clobber previous parameters
2044 which have already been stored into the stack. (we have code to avoid
2045 such case by saving the outgoing stack arguments, but it results in
2046 worse code) */
2051 {
2052 tree type;
2053 machine_mode mode;
2058 /* If this is an addressable type, we cannot pre-evaluate it. */
2067 {
2073 /* CSE will replace this only if it contains args[i].value
2074 pseudo, so convert it down to the declared mode using
2075 a SUBREG. */
2079 {
2084 }
2085 }
2086 }
2087 }
2089 /* Given the current state of MUST_PREALLOCATE and information about
2090 arguments to a function call in NUM_ACTUALS, ARGS and ARGS_SIZE,
2091 compute and return the final value for MUST_PREALLOCATE. */
2093 static int
2096 {
2097 /* See if we have or want to preallocate stack space.
2099 If we would have to push a partially-in-regs parm
2100 before other stack parms, preallocate stack space instead.
2102 If the size of some parm is not a multiple of the required stack
2103 alignment, we must preallocate.
2105 If the total size of arguments that would otherwise create a copy in
2106 a temporary (such as a CALL) is more than half the total argument list
2107 size, preallocation is faster.
2109 Another reason to preallocate is if we have a machine (like the m88k)
2110 where stack alignment is required to be maintained between every
2111 pair of insns, not just when the call is made. However, we assume here
2112 that such machines either do not have push insns (and hence preallocation
2113 would occur anyway) or the problem is taken care of with
2114 PUSH_ROUNDING. */
2117 {
2123 {
2128 /* We preallocate in case there are bounds passed
2129 in the bounds table to have precomputed address
2130 for bounds association. */
2140 copy_to_evaluate_size
2142 }
2147 }
2149 }
2151 /* If we preallocated stack space, compute the address of each argument
2152 and store it into the ARGS array.
2154 We need not ensure it is a valid memory address here; it will be
2155 validized when it is used.
2157 ARGBLOCK is an rtx for the address of the outgoing arguments. */
2159 static void
2161 {
2163 {
2171 {
2174 rtx addr;
2179 /* Skip this parm if it will not be passed on the stack. */
2185 /* Pointer Bounds are never passed on the stack. */
2191 else
2197 {
2198 /* Only part of the parameter is being passed on the stack.
2199 Generate a simple memory reference of the correct size. */
2205 }
2206 else
2207 {
2211 }
2217 {
2220 }
2225 else
2231 {
2232 /* Only part of the parameter is being passed on the stack.
2233 Generate a simple memory reference of the correct size.
2234 */
2237 }
2238 else
2239 {
2243 }
2246 /* Function incoming arguments may overlap with sibling call
2247 outgoing arguments and we cannot allow reordering of reads
2248 from function arguments with stores to outgoing arguments
2249 of sibling calls. */
2252 }
2253 }
2254 }
2256 /* Given a FNDECL and EXP, return an rtx suitable for use as a target address
2257 in a call instruction.
2259 FNDECL is the tree node for the target function. For an indirect call
2260 FNDECL will be NULL_TREE.
2262 ADDR is the operand 0 of CALL_EXPR for this call. */
2264 static rtx
2266 {
2267 rtx funexp;
2269 /* Get the function to call, in the form of RTL. */
2271 {
2275 /* Get a SYMBOL_REF rtx for the function address. */
2277 }
2278 else
2279 /* Generate an rtx (probably a pseudo-register) for the address. */
2280 {
2284 }
2286 }
2288 /* Internal state for internal_arg_pointer_based_exp and its helpers. */
2289 static struct
2290 {
2291 /* Last insn that has been scanned by internal_arg_pointer_based_exp_scan,
2292 or NULL_RTX if none has been scanned yet. */
2294 /* Vector indexed by REGNO - FIRST_PSEUDO_REGISTER, recording if a pseudo is
2295 based on crtl->args.internal_arg_pointer. The element is NULL_RTX if the
2296 pseudo isn't based on it, a CONST_INT offset if the pseudo is based on it
2297 with fixed offset, or PC if this is with variable or unknown offset. */
2303 /* Helper function for internal_arg_pointer_based_exp. Scan insns in
2304 the tail call sequence, starting with first insn that hasn't been
2305 scanned yet, and note for each pseudo on the LHS whether it is based
2306 on crtl->args.internal_arg_pointer or not, and what offset from that
2307 that pointer it has. */
2309 static void
2311 {
2316 else
2320 {
2323 {
2326 /* Punt on pseudos set multiple times. */
2331 else
2334 {
2336 internal_arg_pointer_exp_state.cache
2339 }
2340 }
2344 }
2347 }
2349 /* Compute whether RTL is based on crtl->args.internal_arg_pointer. Return
2350 NULL_RTX if RTL isn't based on it, a CONST_INT offset if RTL is based on
2351 it with fixed offset, or PC if this is with variable or unknown offset.
2352 TOPLEVEL is true if the function is invoked at the topmost level. */
2354 static rtx
2356 {
2367 {
2372 }
2374 /* When called at the topmost level, scan pseudo assignments in between the
2375 last scanned instruction in the tail call sequence and the latest insn
2376 in that sequence. */
2381 {
2387 }
2391 {
2397 }
2400 }
2402 /* Return true if and only if SIZE storage units (usually bytes)
2403 starting from address ADDR overlap with already clobbered argument
2404 area. This function is used to determine if we should give up a
2405 sibcall. */
2407 static bool
2409 {
2410 HOST_WIDE_INT i;
2411 rtx val;
2420 else
2425 else
2433 {
2440 }
2443 }
2445 /* Do the register loads required for any wholly-register parms or any
2446 parms which are passed both on the stack and in a register. Their
2447 expressions were already evaluated.
2449 Mark all register-parms as living through the call, putting these USE
2450 insns in the CALL_INSN_FUNCTION_USAGE field.
2452 When IS_SIBCALL, perform the check_sibcall_argument_overlap
2453 checking, setting *SIBCALL_FAILURE if appropriate. */
2455 static void
2459 {
2463 {
2467 {
2472 /* Set non-negative if we must move a word at a time, even if
2473 just one word (e.g, partial == 4 && mode == DFmode). Set
2474 to -1 if we just use a normal move insn. This value can be
2475 zero if the argument is a zero size structure. */
2478 ;
2480 {
2483 }
2485 {
2488 }
2489 else
2492 /* Handle calls that pass values in multiple non-contiguous
2493 locations. The Irix 6 ABI has examples of this. */
2498 /* If simple case, just do move. If normal partial, store_one_arg
2499 has already loaded the register for us. In all other cases,
2500 load the register(s) from memory. */
2503 {
2505 #ifdef BLOCK_REG_PADDING
2506 /* Handle case where we have a value that needs shifting
2507 up to the msb. eg. a QImode value and we're padding
2508 upward on a BYTES_BIG_ENDIAN machine. */
2512 {
2513 rtx x;
2516 /* Assigning REG here rather than a temp makes CALL_FUSAGE
2517 report the whole reg as used. Strictly speaking, the
2518 call only uses SIZE bytes at the msb end, but it doesn't
2519 seem worth generating rtl to say that. */
2524 }
2525 #endif
2526 }
2528 /* If we have pre-computed the values to put in the registers in
2529 the case of non-aligned structures, copy them in now. */
2537 {
2540 /* Check for overlap with already clobbered argument area,
2541 providing that this has non-zero size. */
2544 && (mem_overlaps_already_clobbered_arg_p
2551 else
2552 {
2566 }
2568 /* Handle a BLKmode that needs shifting. */
2570 #ifdef BLOCK_REG_PADDING
2572 #else
2573 && BYTES_BIG_ENDIAN
2574 #endif
2575 )
2576 {
2581 rtx x;
2586 }
2587 }
2589 /* When a parameter is a block, and perhaps in other cases, it is
2590 possible that it did a load from an argument slot that was
2591 already clobbered. */
2596 /* Handle calls that pass values in multiple non-contiguous
2597 locations. The Irix 6 ABI has examples of this. */
2605 }
2606 }
2607 }
2609 /* We need to pop PENDING_STACK_ADJUST bytes. But, if the arguments
2610 wouldn't fill up an even multiple of PREFERRED_UNIT_STACK_BOUNDARY
2611 bytes, then we would need to push some additional bytes to pad the
2612 arguments. So, we compute an adjust to the stack pointer for an
2613 amount that will leave the stack under-aligned by UNADJUSTED_ARGS_SIZE
2614 bytes. Then, when the arguments are pushed the stack will be perfectly
2615 aligned. ARGS_SIZE->CONSTANT is set to the number of bytes that should
2616 be popped after the call. Returns the adjustment. */
2618 static int
2622 {
2623 /* The number of bytes to pop so that the stack will be
2624 under-aligned by UNADJUSTED_ARGS_SIZE bytes. */
2625 HOST_WIDE_INT adjustment;
2626 /* The alignment of the stack after the arguments are pushed, if we
2627 just pushed the arguments without adjust the stack here. */
2630 unadjusted_alignment
2634 /* We want to get rid of as many of the PENDING_STACK_ADJUST bytes
2635 as possible -- leaving just enough left to cancel out the
2636 UNADJUSTED_ALIGNMENT. In other words, we want to ensure that the
2637 PENDING_STACK_ADJUST is non-negative, and congruent to
2638 -UNADJUSTED_ALIGNMENT modulo the PREFERRED_UNIT_STACK_BOUNDARY. */
2640 /* Begin by trying to pop all the bytes. */
2641 unadjusted_alignment
2642 = (unadjusted_alignment
2645 /* Push enough additional bytes that the stack will be aligned
2646 after the arguments are pushed. */
2648 {
2651 else
2653 }
2655 /* Now, sets ARGS_SIZE->CONSTANT so that we pop the right number of
2656 bytes after the call. The right number is the entire
2657 PENDING_STACK_ADJUST less our ADJUSTMENT plus the amount required
2658 by the arguments in the first place. */
2659 args_size->constant
2663 }
2665 /* Scan X expression if it does not dereference any argument slots
2666 we already clobbered by tail call arguments (as noted in stored_args_map
2667 bitmap).
2668 Return nonzero if X expression dereferences such argument slots,
2669 zero otherwise. */
2671 static int
2673 {
2674 RTX_CODE code;
2683 /* We need not check the operands of the CALL expression itself. */
2691 /* Scan all subexpressions. */
2694 {
2696 {
2699 }
2701 {
2705 }
2706 }
2708 }
2710 /* Scan sequence after INSN if it does not dereference any argument slots
2711 we already clobbered by tail call arguments (as noted in stored_args_map
2712 bitmap). If MARK_STORED_ARGS_MAP, add stack slots for ARG to
2713 stored_args_map bitmap afterwards (when ARG is a register MARK_STORED_ARGS_MAP
2714 should be 0). Return nonzero if sequence after INSN dereferences such argument
2715 slots, zero otherwise. */
2717 static int
2720 {
2725 else
2734 {
2737 else
2742 }
2744 }
2746 /* Given that a function returns a value of mode MODE at the most
2747 significant end of hard register VALUE, shift VALUE left or right
2748 as specified by LEFT_P. Return true if some action was needed. */
2750 bool
2752 {
2753 HOST_WIDE_INT shift;
2760 /* Use ashr rather than lshr for right shifts. This is for the benefit
2761 of the MIPS port, which requires SImode values to be sign-extended
2762 when stored in 64-bit registers. */
2767 }
2769 /* If X is a likely-spilled register value, copy it to a pseudo
2770 register and return that register. Return X otherwise. */
2772 static rtx
2774 {
2775 rtx new_rtx;
2780 {
2781 /* Make sure that we generate a REG rather than a CONCAT.
2782 Moves into CONCATs can need nontrivial instructions,
2783 and the whole point of this function is to avoid
2784 using the hard register directly in such a situation. */
2790 }
2792 }
2794 /* Helper function for expand_call.
2795 Return false is EXP is not implementable as a sibling call. */
2797 static bool
2799 rtx structure_value_addr,
2800 tree funtype,
2802 tree fndecl,
2804 tree addr,
2806 {
2808 {
2809 maybe_complain_about_tail_call
2811 "machine description does not have"
2814 }
2816 /* Doing sibling call optimization needs some work, since
2817 structure_value_addr can be allocated on the stack.
2818 It does not seem worth the effort since few optimizable
2819 sibling calls will return a structure. */
2821 {
2824 }
2826 #ifdef REG_PARM_STACK_SPACE
2827 /* If outgoing reg parm stack space changes, we can not do sibcall. */
2831 {
2833 "inconsistent size of stack space"
2834 " allocated for arguments which are"
2837 }
2838 #endif
2840 /* Check whether the target is able to optimize the call
2841 into a sibcall. */
2843 {
2845 "target is not able to optimize the"
2848 }
2850 /* Functions that do not return exactly once may not be sibcall
2851 optimized. */
2853 {
2856 }
2858 {
2861 }
2864 {
2867 }
2869 /* If the called function is nested in the current one, it might access
2870 some of the caller's arguments, but could clobber them beforehand if
2871 the argument areas are shared. */
2873 {
2876 }
2878 /* If this function requires more stack slots than the current
2879 function, we cannot change it into a sibling call.
2880 crtl->args.pretend_args_size is not part of the
2881 stack allocated by our caller. */
2883 {
2885 "callee required more stack slots"
2888 }
2890 /* If the callee pops its own arguments, then it must pop exactly
2891 the same number of arguments as the current function. */
2896 {
2898 "inconsistent number of"
2901 }
2904 {
2908 }
2910 /* All checks passed. */
2912 }
2914 /* Generate all the code for a CALL_EXPR exp
2915 and return an rtx for its value.
2916 Store the value in TARGET (specified as an rtx) if convenient.
2917 If the value is stored in TARGET then TARGET is returned.
2918 If IGNORE is nonzero, then we ignore the value of the function call. */
2920 rtx
2922 {
2923 /* Nonzero if we are currently expanding a call. */
2926 /* RTX for the function to be called. */
2927 rtx funexp;
2928 /* Sequence of insns to perform a normal "call". */
2930 /* Sequence of insns to perform a tail "call". */
2932 /* Data type of the function. */
2933 tree funtype;
2934 tree type_arg_types;
2935 tree rettype;
2936 /* Declaration of the function being called,
2937 or 0 if the function is computed (not known by name). */
2939 /* The type of the function being called. */
2940 tree fntype;
2945 /* Register in which non-BLKmode value will be returned,
2946 or 0 if no value or if value is BLKmode. */
2947 rtx valreg;
2948 /* Register(s) in which bounds are returned. */
2950 /* Address where we should return a BLKmode value;
2951 0 if value not BLKmode. */
2953 /* Nonzero if that address is being passed by treating it as
2954 an extra, implicit first parameter. Otherwise,
2955 it is passed by being copied directly into struct_value_rtx. */
2957 /* Holds the value of implicit argument for the struct value. */
2959 /* Size of aggregate value wanted, or zero if none wanted
2960 or if we are using the non-reentrant PCC calling convention
2961 or expecting the value in registers. */
2963 /* Nonzero if called function returns an aggregate in memory PCC style,
2964 by returning the address of where to find it. */
2968 /* Number of actual parameters in this call, including struct value addr. */
2970 /* Number of named args. Args after this are anonymous ones
2971 and they must all go on the stack. */
2973 /* Number of complex actual arguments that need to be split. */
2976 /* Vector of information about each argument.
2977 Arguments are numbered in the order they will be pushed,
2978 not the order they are written. */
2981 /* Total size in bytes of all the stack-parms scanned so far. */
2984 /* Size of arguments before any adjustments (such as rounding). */
2986 /* Data on reg parms scanned so far. */
2987 CUMULATIVE_ARGS args_so_far_v;
2988 cumulative_args_t args_so_far;
2989 /* Nonzero if a reg parm has been scanned. */
2991 /* Nonzero if this is an indirect function call. */
2993 /* Nonzero if we must avoid push-insns in the args for this call.
2994 If stack space is allocated for register parameters, but not by the
2995 caller, then it is preallocated in the fixed part of the stack frame.
2996 So the entire argument block must then be preallocated (i.e., we
2997 ignore PUSH_ROUNDING in that case). */
3001 /* Size of the stack reserved for parameter registers. */
3004 /* Address of space preallocated for stack parms
3005 (on machines that lack push insns), or 0 if space not preallocated. */
3008 /* Mask of ECF_ and ERF_ flags. */
3011 #ifdef REG_PARM_STACK_SPACE
3012 /* Define the boundary of the register parm stack space that needs to be
3013 saved, if any. */
3016 #endif
3024 /* State variables to track stack modifications. */
3030 /* Some stack pointer alterations we make are performed via
3031 allocate_dynamic_stack_space. This modifies the stack_pointer_delta,
3032 which we then also need to save/restore along the way. */
3035 rtx call_fusage;
3038 /* The alignment of the stack, in bits. */
3040 /* The alignment of the stack, in bytes. */
3042 /* The static chain value to use for this call. */
3043 rtx static_chain_value;
3044 /* See if this is "nothrow" function call. */
3048 /* See if we can find a DECL-node for the actual function, and get the
3049 function attributes (flags) from the function decl or type node. */
3052 {
3056 }
3057 else
3058 {
3063 }
3068 /* Warn if this value is an aggregate type,
3069 regardless of which calling convention we are using for it. */
3073 /* If the result of a non looping pure or const function call is
3074 ignored (or void), and none of its arguments are volatile, we can
3075 avoid expanding the call and just evaluate the arguments for
3076 side-effects. */
3081 {
3083 tree arg;
3084 call_expr_arg_iterator iter;
3088 {
3091 }
3094 {
3098 }
3099 }
3101 #ifdef REG_PARM_STACK_SPACE
3103 #endif
3109 /* Set up a place to return a structure. */
3111 /* Cater to broken compilers. */
3113 {
3114 /* This call returns a big structure. */
3117 #ifdef PCC_STATIC_STRUCT_RETURN
3118 {
3120 }
3122 {
3125 /* Even if it is semantically safe to use the target as the return
3126 slot, it may be not sufficiently aligned for the return type. */
3128 && target
3134 else
3135 {
3136 /* For variable-sized objects, we must be called with a target
3137 specified. If we were to allocate space on the stack here,
3138 we would have no way of knowing when to free it. */
3142 }
3143 }
3145 }
3147 /* Figure out the amount to which the stack should be aligned. */
3150 {
3152 /* Without automatic stack alignment, we can't increase preferred
3153 stack boundary. With automatic stack alignment, it is
3154 unnecessary since unless we can guarantee that all callers will
3155 align the outgoing stack properly, callee has to align its
3156 stack anyway. */
3161 }
3163 /* Operand 0 is a pointer-to-function; get the type of the function. */
3168 /* Count whether there are actual complex arguments that need to be split
3169 into their real and imaginary parts. Munge the type_arg_types
3170 appropriately here as well. */
3172 {
3173 call_expr_arg_iterator iter;
3174 tree arg;
3176 {
3180 num_complex_actuals++;
3181 }
3183 }
3184 else
3190 /* If struct_value_rtx is 0, it means pass the address
3191 as if it were an extra parameter. Put the argument expression
3192 in structure_value_addr_value. */
3194 {
3195 /* If structure_value_addr is a REG other than
3196 virtual_outgoing_args_rtx, we can use always use it. If it
3197 is not a REG, we must always copy it into a register.
3198 If it is virtual_outgoing_args_rtx, we must copy it to another
3199 register in some cases. */
3201 || (ACCUMULATE_OUTGOING_ARGS
3202 && stack_arg_under_construction
3208 structure_value_addr_value =
3211 }
3213 /* Count the arguments and set NUM_ACTUALS. */
3214 num_actuals =
3217 /* Compute number of named args.
3218 First, do a raw count of the args for INIT_CUMULATIVE_ARGS. */
3221 n_named_args
3223 /* Count the struct value address, if it is passed as a parm. */
3225 else
3226 /* If we know nothing, treat all args as named. */
3229 /* Start updating where the next arg would go.
3231 On some machines (such as the PA) indirect calls have a different
3232 calling convention than normal calls. The fourth argument in
3233 INIT_CUMULATIVE_ARGS tells the backend if this is an indirect call
3234 or not. */
3238 /* Now possibly adjust the number of named args.
3239 Normally, don't include the last named arg if anonymous args follow.
3240 We do include the last named arg if
3241 targetm.calls.strict_argument_naming() returns nonzero.
3242 (If no anonymous args follow, the result of list_length is actually
3243 one too large. This is harmless.)
3245 If targetm.calls.pretend_outgoing_varargs_named() returns
3246 nonzero, and targetm.calls.strict_argument_naming() returns zero,
3247 this machine will be able to place unnamed args that were passed
3248 in registers into the stack. So treat all args as named. This
3249 allows the insns emitting for a specific argument list to be
3250 independent of the function declaration.
3252 If targetm.calls.pretend_outgoing_varargs_named() returns zero,
3253 we do not have any reliable way to pass unnamed args in
3254 registers, so we must force them into memory. */
3258 ;
3261 /* Don't include the last named arg. */
3263 else
3264 /* Treat all args as named. */
3267 /* Make a vector to hold all the information about each arg. */
3270 /* Build up entries in the ARGS array, compute the size of the
3271 arguments into ARGS_SIZE, etc. */
3283 /* Now make final decision about preallocating stack space. */
3288 /* If the structure value address will reference the stack pointer, we
3289 must stabilize it. We don't need to do this if we know that we are
3290 not going to adjust the stack pointer in processing this call. */
3295 structure_value_addr))
3300 /* Tail calls can make things harder to debug, and we've traditionally
3301 pushed these optimizations into -O2. Don't try if we're already
3302 expanding a call, as that means we're an argument. Don't try if
3303 there's cleanups, as we know there's code to follow the call. */
3306 || !flag_optimize_sibling_calls
3311 /* If the user has marked the function as requiring tail-call
3312 optimization, attempt it. */
3316 /* Rest of purposes for tail call optimizations to fail. */
3319 structure_value_addr,
3320 funtype,
3321 reg_parm_stack_space,
3322 fndecl,
3325 /* Check if caller and callee disagree in promotion of function
3326 return value. */
3328 {
3338 caller_promoted_mode
3342 callee_promoted_mode
3353 {
3356 "caller and callee disagree in"
3357 " promotion of function"
3359 }
3360 }
3362 /* Ensure current function's preferred stack boundary is at least
3363 what we need. Stack alignment may also increase preferred stack
3364 boundary. */
3367 else
3372 /* We want to make two insn chains; one for a sibling call, the other
3373 for a normal call. We will select one of the two chains after
3374 initial RTL generation is complete. */
3376 {
3378 /* We want to emit any pending stack adjustments before the tail
3379 recursion "call". That way we know any adjustment after the tail
3380 recursion call can be ignored if we indeed use the tail
3381 call expansion. */
3382 saved_pending_stack_adjust save;
3384 rtx next_arg_reg;
3387 {
3388 /* State variables we need to save and restore between
3389 iterations. */
3391 }
3394 else
3397 /* Other state variables that we must reinitialize each time
3398 through the loop (that are not initialized by the loop itself). */
3402 /* Start a new sequence for the normal call case.
3404 From this point on, if the sibling call fails, we want to set
3405 sibcall_failure instead of continuing the loop. */
3408 /* Don't let pending stack adjusts add up to too much.
3409 Also, do all pending adjustments now if there is any chance
3410 this might be a call to alloca or if we are expanding a sibling
3411 call sequence.
3412 Also do the adjustments before a throwing call, otherwise
3413 exception handling can fail; PR 19225. */
3422 /* Precompute any arguments as needed. */
3426 /* Now we are about to start emitting insns that can be deleted
3427 if a libcall is deleted. */
3437 /* Compute the actual size of the argument block required. The variable
3438 and constant sizes must be combined, the size may have to be rounded,
3439 and there may be a minimum required size. When generating a sibcall
3440 pattern, do not round up, since we'll be re-using whatever space our
3441 caller provided. */
3442 unadjusted_args_size
3451 /* The argument block when performing a sibling call is the
3452 incoming argument block. */
3454 {
3457 argblock
3459 else
3460 argblock
3465 }
3467 /* If we have no actual push instructions, or shouldn't use them,
3468 make space for all args right now. */
3470 {
3472 {
3477 /* stack_arg_under_construction says whether a stack arg is
3478 being constructed at the old stack level. Pushing the stack
3479 gets a clean outgoing argument block. */
3482 }
3486 }
3487 else
3488 {
3489 /* Note that we must go through the motions of allocating an argument
3490 block even if the size is zero because we may be storing args
3491 in the area reserved for register arguments, which may be part of
3492 the stack frame. */
3496 /* Store the maximum argument space used. It will be pushed by
3497 the prologue (if ACCUMULATE_OUTGOING_ARGS, or stack overflow
3498 checking). */
3504 {
3506 {
3507 /* Since the stack pointer will never be pushed, it is
3508 possible for the evaluation of a parm to clobber
3509 something we have already written to the stack.
3510 Since most function calls on RISC machines do not use
3511 the stack, this is uncommon, but must work correctly.
3513 Therefore, we save any area of the stack that was already
3514 written and that we are using. Here we set up to do this
3515 by making a new stack usage map from the old one. The
3516 actual save will be done by store_one_arg.
3518 Another approach might be to try to reorder the argument
3519 evaluations to avoid this conflicting stack usage. */
3521 /* Since we will be writing into the entire argument area,
3522 the map must be allocated for its entire size, not just
3523 the part that is the responsibility of the caller. */
3528 highest_outgoing_arg_in_use
3530 else
3531 highest_outgoing_arg_in_use
3540 initial_highest_arg_in_use);
3544 (highest_outgoing_arg_in_use
3548 /* The address of the outgoing argument list must not be
3549 copied to a register here, because argblock would be left
3550 pointing to the wrong place after the call to
3551 allocate_dynamic_stack_space below. */
3554 }
3555 else
3556 {
3558 {
3559 /* Try to reuse some or all of the pending_stack_adjust
3560 to get this space. */
3561 needed
3562 = (combine_pending_stack_adjustment_and_call
3565 preferred_unit_stack_boundary));
3567 /* combine_pending_stack_adjustment_and_call computes
3568 an adjustment before the arguments are allocated.
3569 Account for them and see whether or not the stack
3570 needs to go up or down. */
3574 {
3575 /* We're releasing stack space. */
3576 /* ??? We can avoid any adjustment at all if we're
3577 already aligned. FIXME. */
3581 }
3582 else
3583 /* We need to allocate space. We'll do that in
3584 push_block below. */
3586 }
3588 /* Special case this because overhead of `push_block' in
3589 this case is non-trivial. */
3592 else
3593 {
3597 }
3599 /* We only really need to call `copy_to_reg' in the case
3600 where push insns are going to be used to pass ARGBLOCK
3601 to a function call in ARGS. In that case, the stack
3602 pointer changes value from the allocation point to the
3603 call point, and hence the value of
3604 VIRTUAL_OUTGOING_ARGS_RTX changes as well. But might
3605 as well always do it. */
3607 }
3608 }
3609 }
3612 {
3613 /* The save/restore code in store_one_arg handles all
3614 cases except one: a constructor call (including a C
3615 function returning a BLKmode struct) to initialize
3616 an argument. */
3618 {
3619 rtx push_size
3625 {
3630 /* stack_arg_under_construction says whether a stack
3631 arg is being constructed at the old stack level.
3632 Pushing the stack gets a clean outgoing argument
3633 block. */
3634 old_stack_arg_under_construction
3637 /* Make a new map for the new argument list. */
3642 }
3643 /* We can pass TRUE as the 4th argument because we just
3644 saved the stack pointer and will restore it right after
3645 the call. */
3648 }
3650 /* If argument evaluation might modify the stack pointer,
3651 copy the address of the argument list to a register. */
3654 {
3657 }
3658 }
3662 /* Stack is properly aligned, pops can't safely be deferred during
3663 the evaluation of the arguments. */
3664 NO_DEFER_POP;
3666 /* Precompute all register parameters. It isn't safe to compute
3667 anything once we have started filling any specific hard regs.
3668 TLS symbols sometimes need a call to resolve. Precompute
3669 register parameters before any stack pointer manipulation
3670 to avoid unaligned stack in the called function. */
3673 OK_DEFER_POP;
3675 /* Perform stack alignment before the first push (the last arg). */
3679 {
3680 /* When the stack adjustment is pending, we get better code
3681 by combining the adjustments. */
3684 {
3685 pending_stack_adjust
3686 = (combine_pending_stack_adjustment_and_call
3689 preferred_unit_stack_boundary));
3691 }
3695 }
3696 /* Now that the stack is properly aligned, pops can't safely
3697 be deferred during the evaluation of the arguments. */
3698 NO_DEFER_POP;
3700 /* Record the maximum pushed stack space size. We need to delay
3701 doing it this far to take into account the optimization done
3702 by combine_pending_stack_adjustment_and_call. */
3704 && !ACCUMULATE_OUTGOING_ARGS
3705 && pass
3707 {
3711 }
3717 else
3720 #ifdef REG_PARM_STACK_SPACE
3721 /* Save the fixed argument area if it's part of the caller's frame and
3722 is clobbered by argument setup for this call. */
3726 #endif
3728 /* Now store (and compute if necessary) all non-register parms.
3729 These come before register parms, since they can require block-moves,
3730 which could clobber the registers used for register parms.
3731 Parms which have partial registers are not stored here,
3732 but we do preallocate space here if they want that. */
3735 {
3736 /* Delay bounds until all other args are stored. */
3740 {
3743 /* We don't allow passing huge (> 2^30 B) arguments
3744 by value. It would cause an overflow later on. */
3747 {
3750 }
3754 reg_parm_stack_space)
3759 }
3762 call_fusage
3765 call_fusage);
3766 }
3768 /* If we have a parm that is passed in registers but not in memory
3769 and whose alignment does not permit a direct copy into registers,
3770 make a group of pseudos that correspond to each register that we
3771 will later fill. */
3775 /* Now store any partially-in-registers parm.
3776 This is the last place a block-move can happen. */
3780 {
3783 /* On targets with weird calling conventions (e.g. PA) it's
3784 hard to ensure that all cases of argument overlap between
3785 stack and registers work. Play it safe and bail out. */
3787 {
3790 }
3794 reg_parm_stack_space)
3799 }
3804 {
3807 }
3811 /* Figure out the register where the value, if any, will come back. */
3816 {
3818 {
3825 }
3826 else
3827 {
3832 fndecl,
3834 }
3836 /* If VALREG is a PARALLEL whose first member has a zero
3837 offset, use that. This is for targets such as m68k that
3838 return the same value in multiple places. */
3840 {
3847 }
3848 }
3850 /* Store all bounds not passed in registers. */
3852 {
3857 ? NULL
3859 }
3861 /* If register arguments require space on the stack and stack space
3862 was not preallocated, allocate stack space here for arguments
3863 passed in registers. */
3865 && !ACCUMULATE_OUTGOING_ARGS
3869 /* Pass the function the address in which to return a
3870 structure value. */
3872 {
3873 structure_value_addr
3878 NULL_RTX)));
3882 }
3892 /* Save a pointer to the last insn before the call, so that we can
3893 later safely search backwards to find the CALL_INSN. */
3896 /* Set up next argument register. For sibling calls on machines
3897 with register windows this should be the incoming register. */
3900 VOIDmode,
3901 void_type_node,
3903 else
3909 {
3915 && valreg
3918 call_fusage
3921 call_fusage);
3922 }
3923 /* All arguments and registers used for the call must be set up by
3924 now! */
3926 /* Stack must be properly aligned now. */
3930 /* Generate the actual call instruction. */
3937 {
3941 {
3945 }
3948 }
3950 /* If the call setup or the call itself overlaps with anything
3951 of the argument setup we probably clobbered our call address.
3952 In that case we can't do sibcalls. */
3957 /* If a non-BLKmode value is returned at the most significant end
3958 of a register, shift the register right by the appropriate amount
3959 and update VALREG accordingly. BLKmode values are handled by the
3960 group load/store machinery below. */
3962 && !pcc_struct_value
3967 {
3971 }
3974 {
3978 /* The return value from a malloc-like function is a pointer. */
3984 /* The return value from a malloc-like function can not alias
3985 anything else. */
3989 /* Write out the sequence. */
3994 }
3996 /* For calls to `setjmp', etc., inform
3997 function.c:setjmp_warnings that it should complain if
3998 nonvolatile values are live. For functions that cannot
3999 return, inform flow that control does not fall through. */
4002 {
4003 /* The barrier must be emitted
4004 immediately after the CALL_INSN. Some ports emit more
4005 than just a CALL_INSN above, so we must search for it here. */
4009 {
4011 /* There was no CALL_INSN? */
4013 }
4017 /* Stack adjustments after a noreturn call are dead code.
4018 However when NO_DEFER_POP is in effect, we must preserve
4019 stack_pointer_delta. */
4021 {
4024 }
4025 }
4027 /* If value type not void, return an rtx for the value. */
4033 {
4035 {
4036 target
4039 structure_value_addr));
4041 }
4042 }
4044 {
4045 /* This is the special C++ case where we need to
4046 know what the true target was. We take care to
4047 never use this value more than once in one expression. */
4051 }
4052 /* Handle calls that return values in multiple non-contiguous locations.
4053 The Irix 6 ABI has examples of this. */
4055 {
4059 ;
4061 /* Handle the result of a emit_group_move_into_temps
4062 call in the previous pass. */
4064 else
4067 }
4071 {
4074 /* We have to copy a return value in a CLASS_LIKELY_SPILLED hard
4075 reg to a plain register. */
4079 /* If TARGET is a MEM in the argument area, and we have
4080 saved part of the argument area, then we can't store
4081 directly into TARGET as it may get overwritten when we
4082 restore the argument save area below. Don't work too
4083 hard though and simply force TARGET to a register if it
4084 is a MEM; the optimizer is quite likely to sort it out. */
4088 {
4091 }
4095 else
4096 {
4097 /* TARGET and VALREG cannot be equal at this point
4098 because the latter would not have
4099 REG_FUNCTION_VALUE_P true, while the former would if
4100 it were referring to the same register.
4102 If they refer to the same register, this move will be
4103 a no-op, except when function inlining is being
4104 done. */
4107 /* If we are setting a MEM, this code must be executed.
4108 Since it is emitted after the call insn, sibcall
4109 optimization cannot be performed in that case. */
4112 }
4113 }
4114 else
4117 /* If we promoted this return value, make the proper SUBREG.
4118 TARGET might be const0_rtx here, so be careful. */
4122 {
4126 machine_mode pmode;
4128 /* Ensure we promote as expected, and get the new unsignedness. */
4136 {
4143 }
4148 }
4150 /* If size of args is variable or this was a constructor call for a stack
4151 argument, restore saved stack-pointer value. */
4154 {
4168 }
4170 {
4171 #ifdef REG_PARM_STACK_SPACE
4175 #endif
4177 /* If we saved any argument areas, restore them. */
4180 {
4182 rtx stack_area
4189 else
4192 BLOCK_OP_CALL_PARM);
4193 }
4197 }
4199 /* If this was alloca, record the new stack level. */
4203 /* Free up storage we no longer need. */
4213 {
4216 /* Restore the pending stack adjustment now that we have
4217 finished generating the sibling call sequence. */
4221 /* Prepare arg structure for next iteration. */
4223 {
4227 }
4232 }
4233 else
4234 {
4237 /* Verify that we've deallocated all the stack we used. */
4239 || (old_stack_allocated
4241 }
4243 /* If something prevents making this a sibling call,
4244 zero out the sequence. */
4247 else
4249 }
4251 /* If tail call production succeeded, we need to remove REG_EQUIV notes on
4252 arguments too, as argument area is now clobbered by the call. */
4254 {
4257 }
4258 else
4259 {
4262 /* Ideally we'd emit a message for all of the ways that it could
4263 have failed. */
4265 }
4267 currently_expanding_call--;
4272 /* Join result with returned bounds so caller may use them if needed. */
4276 }
4278 /* A sibling call sequence invalidates any REG_EQUIV notes made for
4279 this function's incoming arguments.
4281 At the start of RTL generation we know the only REG_EQUIV notes
4282 in the rtl chain are those for incoming arguments, so we can look
4283 for REG_EQUIV notes between the start of the function and the
4284 NOTE_INSN_FUNCTION_BEG.
4286 This is (slight) overkill. We could keep track of the highest
4287 argument we clobber and be more selective in removing notes, but it
4288 does not seem to be worth the effort. */
4290 void
4292 {
4296 {
4297 rtx note;
4299 /* There are never REG_EQUIV notes for the incoming arguments
4300 after the NOTE_INSN_FUNCTION_BEG note, so stop if we see it. */
4310 }
4311 }
4313 /* Traverse a list of TYPES and expand all complex types into their
4314 components. */
4315 static tree
4317 {
4318 tree p;
4320 /* Before allocating memory, check for the common case of no complex. */
4322 {
4327 }
4330 found:
4334 {
4339 {
4342 /* Rewrite complex type with component type. */
4346 /* Add another component type for the imaginary part. */
4351 /* Skip the newly created node. */
4353 }
4354 }
4357 }
4358 \f
4359 /* Output a library call to function FUN (a SYMBOL_REF rtx).
4360 The RETVAL parameter specifies whether return value needs to be saved, other
4361 parameters are documented in the emit_library_call function below. */
4363 static rtx
4367 {
4368 /* Total size in bytes of all the stack-parms scanned so far. */
4370 /* Size of arguments before any adjustments (such as rounding). */
4373 rtx fun;
4374 /* Todo, choose the correct decl type of orgfun. Sadly this information
4375 isn't present here, so we default to native calling abi here. */
4380 CUMULATIVE_ARGS args_so_far_v;
4381 cumulative_args_t args_so_far;
4382 struct arg
4383 {
4384 rtx value;
4385 machine_mode mode;
4386 rtx reg;
4389 rtx save_area;
4390 };
4395 rtx valreg;
4405 #ifdef REG_PARM_STACK_SPACE
4406 /* Define the boundary of the register parm stack space that needs to be
4407 save, if any. */
4410 #endif
4412 /* Size of the stack reserved for parameter registers. */
4419 #ifdef REG_PARM_STACK_SPACE
4421 #endif
4423 /* By default, library functions cannot throw. */
4427 {
4445 }
4448 /* Ensure current function's preferred stack boundary is at least
4449 what we need. */
4453 /* If this kind of value comes back in memory,
4454 decide where in memory it should come back. */
4456 {
4459 {
4460 #ifdef PCC_STATIC_STRUCT_RETURN
4461 rtx pointer_reg
4471 else
4473 #endif
4474 /* This call returns a big structure. */
4476 }
4477 }
4478 else
4481 /* ??? Unfinished: must pass the memory address as an argument. */
4483 /* Copy all the libcall-arguments out of the varargs data
4484 and into a vector ARGVEC.
4486 Compute how to pass each argument. We only support a very small subset
4487 of the full argument passing conventions to limit complexity here since
4488 library functions shouldn't have many args. */
4493 #ifdef INIT_CUMULATIVE_LIBCALL_ARGS
4495 #else
4497 #endif
4507 /* If there's a structure value address to be passed,
4508 either pass it in the special place, or pass it as an extra argument. */
4510 {
4513 nargs++;
4515 /* Make sure it is a reasonable operand for a move or push insn. */
4531 #ifdef STACK_PARMS_IN_REG_PARM_AREA
4533 #else
4535 #endif
4545 count++;
4546 }
4549 {
4554 /* We cannot convert the arg value to the mode the library wants here;
4555 must do it earlier where we know the signedness of the arg. */
4559 /* Make sure it is a reasonable operand for a move or push insn. */
4565 {
4566 rtx slot;
4567 int must_copy
4570 /* If this was a CONST function, it is now PURE since it now
4571 reads memory. */
4573 {
4576 }
4579 {
4584 }
4585 else
4586 {
4590 }
4594 call_fusage);
4598 slot),
4599 call_fusage);
4603 }
4617 {
4619 #ifdef STACK_PARMS_IN_REG_PARM_AREA
4621 #else
4623 #endif
4628 }
4629 #ifdef BLOCK_REG_PADDING
4630 else
4631 /* The argument is passed entirely in registers. See at which
4632 end it should be padded. */
4636 #endif
4639 }
4641 /* If this machine requires an external definition for library
4642 functions, write one out. */
4647 + stack_pointer_delta
4649 / STACK_BYTES
4654 reg_parm_stack_space);
4663 {
4667 }
4670 {
4671 /* Since the stack pointer will never be pushed, it is possible for
4672 the evaluation of a parm to clobber something we have already
4673 written to the stack. Since most function calls on RISC machines
4674 do not use the stack, this is uncommon, but must work correctly.
4676 Therefore, we save any area of the stack that was already written
4677 and that we are using. Here we set up to do this by making a new
4678 stack usage map from the old one.
4680 Another approach might be to try to reorder the argument
4681 evaluations to avoid this conflicting stack usage. */
4685 /* Since we will be writing into the entire argument area, the
4686 map must be allocated for its entire size, not just the part that
4687 is the responsibility of the caller. */
4694 else
4702 initial_highest_arg_in_use);
4709 /* We must be careful to use virtual regs before they're instantiated,
4710 and real regs afterwards. Loop optimization, for example, can create
4711 new libcalls after we've instantiated the virtual regs, and if we
4712 use virtuals anyway, they won't match the rtl patterns. */
4716 STACK_POINTER_OFFSET);
4717 else
4719 }
4720 else
4721 {
4724 }
4726 /* We push args individually in reverse order, perform stack alignment
4727 before the first push (the last arg). */
4734 #ifdef REG_PARM_STACK_SPACE
4736 {
4737 /* The argument list is the property of the called routine and it
4738 may clobber it. If the fixed area has been used for previous
4739 parameters, we must save and restore it. */
4742 }
4743 #endif
4745 /* When expanding a normal call, args are stored in push order,
4746 which is the reverse of what we have here. */
4750 {
4753 }
4757 /* Push the args that need to be pushed. */
4761 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
4762 are to be pushed. */
4764 {
4773 {
4774 rtx use;
4777 {
4778 /* If this is being stored into a pre-allocated, fixed-size,
4779 stack area, save any previous data at that location. */
4782 {
4783 /* stack_slot is negative, but we want to index stack_usage_map
4784 with positive values. */
4787 }
4788 else
4789 {
4792 }
4795 /* Don't worry about things in the fixed argument area;
4796 it has already been saved. */
4800 i++;
4803 {
4804 /* We need to make a save area. */
4805 unsigned int size
4807 machine_mode save_mode
4809 rtx adr
4812 rtx stack_area
4816 {
4820 );
4824 stack_area,
4826 BLOCK_OP_CALL_PARM);
4827 }
4828 else
4829 {
4833 }
4834 }
4835 }
4840 reg_parm_stack_space,
4843 /* Now mark the segment we just used. */
4848 NO_DEFER_POP;
4850 /* Indicate argument access so that alias.c knows that these
4851 values are live. */
4857 else
4858 {
4859 /* When arguments are pushed, trying to tell alias.c where
4860 exactly this argument is won't work, because the
4861 auto-increment causes confusion. So we merely indicate
4862 that we access something with a known mode somewhere on
4863 the stack. */
4867 }
4871 }
4872 }
4878 /* Now load any reg parms into their regs. */
4880 /* ARGNUM indexes the ARGVEC array in the order in which the arguments
4881 are to be pushed. */
4883 {
4888 #ifdef BLOCK_REG_PADDING
4890 #endif
4892 /* Handle calls that pass values in multiple non-contiguous
4893 locations. The PA64 has examples of this for library calls. */
4897 {
4899 #ifdef BLOCK_REG_PADDING
4902 /* Copied from load_register_parameters. */
4904 /* Handle case where we have a value that needs shifting
4905 up to the msb. eg. a QImode value and we're padding
4906 upward on a BYTES_BIG_ENDIAN machine. */
4910 {
4911 rtx x;
4914 /* Assigning REG here rather than a temp makes CALL_FUSAGE
4915 report the whole reg as used. Strictly speaking, the
4916 call only uses SIZE bytes at the msb end, but it doesn't
4917 seem worth generating rtl to say that. */
4922 }
4923 #endif
4924 }
4926 NO_DEFER_POP;
4927 }
4929 /* Any regs containing parms remain in use through the call. */
4931 {
4936 {
4939 {
4944 }
4945 else
4947 }
4948 }
4950 /* Pass the function the address in which to return a structure value. */
4952 {
4956 NULL_RTX)));
4959 }
4961 /* Don't allow popping to be deferred, since then
4962 cse'ing of library calls could delete a call and leave the pop. */
4963 NO_DEFER_POP;
4967 /* Stack must be properly aligned now. */
4973 /* We pass the old value of inhibit_defer_pop + 1 to emit_call_1, which
4974 will set inhibit_defer_pop to that value. */
4975 /* The return type is needed to decide how many bytes the function pops.
4976 Signedness plays no role in that, so for simplicity, we pretend it's
4977 always signed. We also assume that the list of arguments passed has
4978 no impact, so we pretend it is unknown. */
4984 struct_value_size,
4987 valreg,
4991 {
4996 }
4998 /* Right-shift returned value if necessary. */
5002 {
5005 }
5009 /* For calls to `setjmp', etc., inform function.c:setjmp_warnings
5010 that it should complain if nonvolatile values are live. For
5011 functions that cannot return, inform flow that control does not
5012 fall through. */
5014 {
5015 /* The barrier note must be emitted
5016 immediately after the CALL_INSN. Some ports emit more than
5017 just a CALL_INSN above, so we must search for it here. */
5020 {
5022 /* There was no CALL_INSN? */
5024 }
5027 }
5029 /* Consider that "regular" libcalls, i.e. all of them except for LCT_THROW
5030 and LCT_RETURNS_TWICE, cannot perform non-local gotos. */
5032 {
5035 {
5037 /* There was no CALL_INSN? */
5039 }
5042 }
5044 /* Now restore inhibit_defer_pop to its actual original value. */
5045 OK_DEFER_POP;
5049 /* Copy the value to the right place. */
5051 {
5053 {
5058 }
5060 {
5064 }
5065 else
5066 {
5067 /* Convert to the proper mode if a promotion has been active. */
5069 {
5076 }
5080 else
5082 }
5083 }
5086 {
5087 #ifdef REG_PARM_STACK_SPACE
5091 #endif
5093 /* If we saved any argument areas, restore them. */
5096 {
5105 validize_mem
5108 BLOCK_OP_CALL_PARM);
5109 else
5111 }
5115 }
5121 }
5122 \f
5123 /* Output a library call to function FUN (a SYMBOL_REF rtx)
5124 (emitting the queue unless NO_QUEUE is nonzero),
5125 for a value of mode OUTMODE,
5126 with NARGS different arguments, passed as alternating rtx values
5127 and machine_modes to convert them to.
5129 FN_TYPE should be LCT_NORMAL for `normal' calls, LCT_CONST for
5130 `const' calls, LCT_PURE for `pure' calls, or other LCT_ value for
5131 other types of library calls. */
5133 void
5136 {
5142 }
5143 \f
5144 /* Like emit_library_call except that an extra argument, VALUE,
5145 comes second and says where to store the result.
5146 (If VALUE is zero, this function chooses a convenient way
5147 to return the value.
5149 This function returns an rtx for where the value is to be found.
5150 If VALUE is nonzero, VALUE is returned. */
5152 rtx
5156 {
5157 rtx result;
5166 }
5167 \f
5169 /* Store pointer bounds argument ARG into Bounds Table entry
5170 associated with PARM. */
5171 static void
5173 {
5176 /* We may pass bounds not associated with any pointer. */
5178 {
5182 }
5183 /* Find pointer associated with bounds and where it is
5184 passed. */
5185 else
5186 {
5188 {
5192 }
5194 {
5202 else
5203 {
5206 }
5207 }
5208 else
5209 {
5218 else
5220 }
5221 }
5223 /* Expand bounds. */
5228 }
5230 /* Store a single argument for a function call
5231 into the register or memory area where it must be passed.
5232 *ARG describes the argument value and where to pass it.
5234 ARGBLOCK is the address of the stack-block for all the arguments,
5235 or 0 on a machine where arguments are pushed individually.
5237 MAY_BE_ALLOCA nonzero says this could be a call to `alloca'
5238 so must be careful about how the stack is used.
5240 VARIABLE_SIZE nonzero says that this was a variable-sized outgoing
5241 argument stack. This is used if ACCUMULATE_OUTGOING_ARGS to indicate
5242 that we need not worry about saving and restoring the stack.
5244 FNDECL is the declaration of the function we are calling.
5246 Return nonzero if this arg should cause sibcall failure,
5247 zero otherwise. */
5249 static int
5252 {
5263 /* Push a new temporary level for any temporaries we make for
5264 this argument. */
5268 {
5269 /* If this is being stored into a pre-allocated, fixed-size, stack area,
5270 save any previous data at that location. */
5272 {
5274 {
5275 /* stack_slot is negative, but we want to index stack_usage_map
5276 with positive values. */
5279 else
5283 }
5284 else
5285 {
5288 else
5292 }
5295 /* Don't worry about things in the fixed argument area;
5296 it has already been saved. */
5300 i++;
5303 {
5304 /* We need to make a save area. */
5311 {
5312 arg->save_area
5316 stack_area,
5318 BLOCK_OP_CALL_PARM);
5319 }
5320 else
5321 {
5324 }
5325 }
5326 }
5327 }
5329 /* If this isn't going to be placed on both the stack and in registers,
5330 set up the register and number of words. */
5332 {
5335 else
5338 }
5340 /* Being passed entirely in a register. We shouldn't be called in
5341 this case. */
5344 /* If this arg needs special alignment, don't load the registers
5345 here. */
5349 /* If this is being passed partially in a register, we can't evaluate
5350 it directly into its stack slot. Otherwise, we can. */
5352 {
5353 /* stack_arg_under_construction is nonzero if a function argument is
5354 being evaluated directly into the outgoing argument list and
5355 expand_call must take special action to preserve the argument list
5356 if it is called recursively.
5358 For scalar function arguments stack_usage_map is sufficient to
5359 determine which stack slots must be saved and restored. Scalar
5360 arguments in general have pass_on_stack == 0.
5362 If this argument is initialized by a function which takes the
5363 address of the argument (a C++ constructor or a C function
5364 returning a BLKmode structure), then stack_usage_map is
5365 insufficient and expand_call must push the stack around the
5366 function call. Such arguments have pass_on_stack == 1.
5368 Note that it is always safe to set stack_arg_under_construction,
5369 but this generates suboptimal code if set when not needed. */
5372 stack_arg_under_construction++;
5375 (partial
5380 /* If we are promoting object (or for any other reason) the mode
5381 doesn't agree, convert the mode. */
5388 stack_arg_under_construction--;
5389 }
5391 /* Check for overlap with already clobbered argument area. */
5398 /* Don't allow anything left on stack from computation
5399 of argument to alloca. */
5404 /* If the value is already in the stack slot, we are done. */
5405 ;
5407 {
5411 /* Argument is a scalar, not entirely passed in registers.
5412 (If part is passed in registers, arg->partial says how much
5413 and emit_push_insn will take care of putting it there.)
5415 Push it, and if its size is less than the
5416 amount of space allocated to it,
5417 also bump stack pointer by the additional space.
5418 Note that in C the default argument promotions
5419 will prevent such mismatches. */
5422 /* Compute how much space the push instruction will push.
5423 On many machines, pushing a byte will advance the stack
5424 pointer by a halfword. */
5425 #ifdef PUSH_ROUNDING
5427 #endif
5430 /* Compute how much space the argument should get:
5431 round up to a multiple of the alignment for arguments. */
5437 /* Compute the alignment of the pushed argument. */
5440 {
5443 {
5446 }
5447 }
5449 /* This isn't already where we want it on the stack, so put it there.
5450 This can either be done with push or copy insns. */
5457 /* Unless this is a partially-in-register argument, the argument is now
5458 in the stack. */
5461 }
5462 else
5463 {
5464 /* BLKmode, at least partly to be pushed. */
5468 rtx size_rtx;
5470 /* Pushing a nonscalar.
5471 If part is passed in registers, PARTIAL says how much
5472 and emit_push_insn will take care of putting it there. */
5474 /* Round its size up to a multiple
5475 of the allocation unit for arguments. */
5478 {
5481 }
5482 else
5483 {
5484 /* PUSH_ROUNDING has no effect on us, because emit_push_insn
5485 for BLKmode is careful to avoid it. */
5491 EXPAND_NORMAL);
5492 }
5496 /* When an argument is padded down, the block is aligned to
5497 PARM_BOUNDARY, but the actual argument isn't. */
5499 {
5503 {
5506 }
5507 }
5510 {
5511 /* emit_push_insn might not work properly if arg->value and
5512 argblock + arg->locate.offset areas overlap. */
5521 {
5525 /* arg.locate doesn't contain the pretend_args_size offset,
5526 it's part of argblock. Ensure we don't count it in I. */
5529 else
5532 /* expand_call should ensure this. */
5538 {
5541 }
5543 {
5544 /* Use arg->locate.size.constant instead of size_rtx
5545 because we only care about the part of the argument
5546 on the stack. */
5550 }
5551 else
5552 {
5553 /* Even though they appear to be at the same location,
5554 if part of the outgoing argument is in registers,
5555 they aren't really at the same location. Check for
5556 this by making sure that the incoming size is the
5557 same as the outgoing size. */
5560 }
5561 }
5562 }
5569 /* Unless this is a partially-in-register argument, the argument is now
5570 in the stack.
5572 ??? Unlike the case above, in which we want the actual
5573 address of the data, so that we can load it directly into a
5574 register, here we want the address of the stack slot, so that
5575 it's properly aligned for word-by-word copying or something
5576 like that. It's not clear that this is always correct. */
5579 }
5582 {
5584 arg->parallel_value
5587 }
5589 /* Mark all slots this store used. */
5595 /* Once we have pushed something, pops can't safely
5596 be deferred during the rest of the arguments. */
5597 NO_DEFER_POP;
5599 /* Free any temporary slots made in processing this argument. */
5603 }
5605 /* Nonzero if we do not know how to pass TYPE solely in registers. */
5607 bool
5609 const_tree type)
5610 {
5614 /* If the type has variable size... */
5618 /* If the type is marked as addressable (it is required
5619 to be constructed into the stack)... */
5624 }
5626 /* Another version of the TARGET_MUST_PASS_IN_STACK hook. This one
5627 takes trailing padding of a structure into account. */
5628 /* ??? Should be able to merge these two by examining BLOCK_REG_PADDING. */
5630 bool
5632 {
5636 /* If the type has variable size... */
5640 /* If the type is marked as addressable (it is required
5641 to be constructed into the stack)... */
5645 /* If the padding and mode of the type is such that a copy into
5646 a register would put it into the wrong part of the register. */
5654 }
5656 /* Tell the garbage collector about GTY markers in this source file. */