| blob | bc341bf9ad06ce6c9497e6c7e3b99b69417c6ce6 |
1 ;;;; function call for the x86 VM
3 ;;;; This software is part of the SBCL system. See the README file for
4 ;;;; more information.
5 ;;;;
6 ;;;; This software is derived from the CMU CL system, which was
7 ;;;; written at Carnegie Mellon University and released into the
8 ;;;; public domain. The software is in the public domain and is
9 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
10 ;;;; files for more information.
17 ;;; Make a passing location TN for a local call return PC.
18 ;;;
19 ;;; Always wire the return PC location to the stack in its standard
20 ;;; location.
24 sap-stack-sc-number return-pc-save-offset))
29 ;;; This is similar to MAKE-RETURN-PC-PASSING-LOCATION, but makes a
30 ;;; location to pass OLD-FP in.
31 ;;;
32 ;;; This is wired in both the standard and the local-call conventions,
33 ;;; because we want to be able to assume it's always there. Besides,
34 ;;; the x86 doesn't have enough registers to really make it profitable
35 ;;; to pass it in a register.
39 ocfp-save-offset))
44 ;;; Make the TNs used to hold OLD-FP and RETURN-PC within the current
45 ;;; function. We treat these specially so that the debugger can find
46 ;;; them at a known location.
47 ;;;
48 ;;; Without using a save-tn - which does not make much sense if it is
49 ;;; wired to the stack?
52 control-stack-sc-number
53 ocfp-save-offset)
54 physenv))
58 sap-stack-sc-number return-pc-save-offset)
59 physenv))
61 ;;; Make a TN for the standard argument count passing location. We only
62 ;;; need to make the standard location, since a count is never passed when we
63 ;;; are using non-standard conventions.
66 \f
67 ;;;; frame hackery
69 ;;; This is used for setting up the Old-FP in local call.
75 ;;; We don't have a separate NFP, so we don't need to do anything here.
80 nil))
82 ;;; Accessing a slot from an earlier stack frame is definite hackery.
106 :base frame-pointer
128 :base frame-pointer
141 load)))
150 set)))))))
157 :base frame-pointer
164 complex-double-stack
178 complex-single-stack
197 collect
198 `(,name
204 fp value res))
207 fp new-val value)))))))))
209 ancestor-frame-ref/double-float
212 ancestor-frame-ref/single-float
215 ancestor-frame-ref/complex-double-float
218 ancestor-frame-ref/complex-single-float
221 ancestor-frame-ref/signed-byte-32
224 ancestor-frame-ref/unsigned-byte-32
227 ancestor-frame-ref/unsigned-byte-32
230 ancestor-frame-ref/system-area-pointer
238 ;; Skip space for the function header.
243 ;; The start of the actual code.
244 ;; Save the return-pc.
255 ;;; This is emitted directly before either a known-call-local, call-local,
256 ;;; or a multiple-call-local. All it does is allocate stack space for the
257 ;;; callee (who has the same size stack as us).
268 ;;; Allocate a partial frame for passing stack arguments in a full
269 ;;; call. NARGS is the number of arguments passed. We allocate at
270 ;;; least 3 slots, because the XEP noise is going to want to use them
271 ;;; before it can extend the stack.
279 \f
280 ;;; Emit code needed at the return-point from an unknown-values call
281 ;;; for a fixed number of values. Values is the head of the TN-REF
282 ;;; list for the locations that the values are to be received into.
283 ;;; Nvals is the number of values that are to be received (should
284 ;;; equal the length of Values).
285 ;;;
286 ;;; If 0 or 1 values are expected, then we just emit an instruction to
287 ;;; reset the SP (which will only be executed when other than 1 value
288 ;;; is returned.)
289 ;;;
290 ;;; In the general case we have to do three things:
291 ;;; -- Default unsupplied register values. This need only be done
292 ;;; when a single value is returned, since register values are
293 ;;; defaulted by the called in the non-single case.
294 ;;; -- Default unsupplied stack values. This needs to be done whenever
295 ;;; there are stack values.
296 ;;; -- Reset SP. This must be done whenever other than 1 value is
297 ;;; returned, regardless of the number of values desired.
307 register-arg-count)
310 ;; The function never returns, it may happen that the code
311 ;; ends right here leavig the :SINGLE-VALUE-RETURN note
312 ;; dangling. Let's emit a NOP.
328 ;; Default the unsupplied registers.
336 for count from 2 below register-arg-count
344 ;; The number of bytes depends on the relative jump instructions.
345 ;; Best case is 31+(n-3)*14, worst case is 35+(n-3)*18. For
346 ;; NVALS=6 that is 73/89 bytes, and for NVALS=7 that is 87/107
347 ;; bytes which is likely better than using the blt below.
352 ;; Branch off to the MV case.
354 ;; Do the single value case.
355 ;; Default the register args
361 ;; Fake other registers so it looks like we returned with all the
362 ;; registers filled in.
382 ;; There are stack args so the frame of the callee is
383 ;; still there, save EDX in its first slot temporalily.
397 ;; We are setting the first stack argument to NIL.
398 ;; The callee's stack frame is dead, save EDX by
399 ;; pushing it to the stack, it will end up at same
400 ;; place as in the (STOREW EDX-TN EBX-TN -1) case
401 ;; above.
406 ;; 91 bytes for this branch.
413 ;; Branch off to the MV case.
415 ;; Default the register args, and set up the stack as if we
416 ;; entered the MV return point.
420 ;; Compute a pointer to where to put the [defaulted] stack values.
427 ;; Load EAX with NIL so we can quickly store it, and set up
428 ;; stuff for the loop.
432 ;; Jump into the default loop.
434 ;; The regs are defaulted. We need to copy any stack arguments,
435 ;; and then default the remaining stack arguments.
437 ;; Compute the number of stack arguments, and if it's zero or
438 ;; less, don't copy any stack arguments.
441 ;; Save EDI.
443 ;; Throw away any unwanted args.
448 ;; Save the number of stack values.
450 ;; Compute a pointer to where the stack args go.
454 ;; Save ESI, and compute a pointer to where the args come from.
460 ;; Do the copy.
465 ;; Restore ESI.
467 ;; Now we have to default the remaining args. Find out how many.
470 ;; If none, then just blow out of here.
474 ;; Load EAX with NIL for fast storing.
476 ;; Do the store.
480 ;; Restore EDI, and reset the stack.
486 \f
487 ;;;; unknown values receiving
489 ;;; Emit code needed at the return point for an unknown-values call
490 ;;; for an arbitrary number of values.
491 ;;;
492 ;;; We do the single and non-single cases with no shared code: there
493 ;;; doesn't seem to be any potential overlap, and receiving a single
494 ;;; value is more important efficiency-wise.
495 ;;;
496 ;;; When there is a single value, we just push it on the stack,
497 ;;; returning the old SP and 1.
498 ;;;
499 ;;; When there is a variable number of values, we move all of the
500 ;;; argument registers onto the stack, and return ARGS and NARGS.
501 ;;;
502 ;;; ARGS and NARGS are TNs wired to the named locations. We must
503 ;;; explicitly allocate these TNs, since their lifetimes overlap with
504 ;;; the results start and count. (Also, it's nice to be able to target
505 ;;; them.)
522 ;; The stack frame is burnt and RETurned from if there are no
523 ;; stack values. In this case quickly reallocate sufficient space.
525 register-arg-count)
530 ;; dtc: this writes the registers onto the stack even if they are
531 ;; not needed, only the number specified in ecx are used and have
532 ;; stack allocated to them. No harm is done.
535 for i downfrom -1
544 ;;; VOP that can be inherited by unknown values receivers. The main thing this
545 ;;; handles is allocation of the result temporaries.
549 values-start)
552 nvals)
555 \f
556 ;;;; local call with unknown values convention return
559 #+nil
563 #+nil
575 ;;; The local call convention doesn't fit that well with x86-style
576 ;;; calls. Emit a header for local calls to pop the return address
577 ;;; in the right place.
587 ;;; Non-TR local call for a fixed number of values passed according to
588 ;;; the unknown values convention.
589 ;;;
590 ;;; FP is the frame pointer in install before doing the call.
591 ;;;
592 ;;; NFP would be the number-stack frame pointer if we had a separate
593 ;;; number stack.
594 ;;;
595 ;;; Args are the argument passing locations, which are specified only
596 ;;; to terminate their lifetimes in the caller.
597 ;;;
598 ;;; VALUES are the return value locations (wired to the standard
599 ;;; passing locations). NVALS is the number of values received.
600 ;;;
601 ;;; Save is the save info, which we can ignore since saving has been
602 ;;; done.
603 ;;;
604 ;;; TARGET is a continuation pointing to the start of the called
605 ;;; function.
623 ;;; Non-TR local call for a variable number of return values passed according
624 ;;; to the unknown values convention. The results are the start of the values
625 ;;; glob and the number of values received.
642 \f
643 ;;;; local call with known values return
645 ;;; Non-TR local call with known return locations. Known-value return
646 ;;; works just like argument passing in local call.
647 ;;;
648 ;;; Note: we can't use normal load-tn allocation for the fixed args,
649 ;;; since all registers may be tied up by the more operand. Instead,
650 ;;; we use MAYBE-LOAD-STACK-TN.
666 \f
667 ;;; From Douglas Crosher
668 ;;; Return from known values call. We receive the return locations as
669 ;;; arguments to terminate their lifetimes in the returning function. We
670 ;;; restore FP and CSP and jump to the Return-PC.
681 ;; Zot all of the stack except for the old-fp and return-pc.
685 \f
686 ;;;; full call
687 ;;;
688 ;;; There is something of a cross-product effect with full calls.
689 ;;; Different versions are used depending on whether we know the
690 ;;; number of arguments or the name of the called function, and
691 ;;; whether we want fixed values, unknown values, or a tail call.
692 ;;;
693 ;;; In full call, the arguments are passed creating a partial frame on
694 ;;; the stack top and storing stack arguments into that frame. On
695 ;;; entry to the callee, this partial frame is pointed to by FP.
697 ;;; This macro helps in the definition of full call VOPs by avoiding
698 ;;; code replication in defining the cross-product VOPs.
699 ;;;
700 ;;; NAME is the name of the VOP to define.
701 ;;;
702 ;;; NAMED is true if the first argument is an fdefinition object whose
703 ;;; definition is to be called.
704 ;;;
705 ;;; RETURN is either :FIXED, :UNKNOWN or :TAIL:
706 ;;; -- If :FIXED, then the call is for a fixed number of values, returned in
707 ;;; the standard passing locations (passed as result operands).
708 ;;; -- If :UNKNOWN, then the result values are pushed on the stack, and the
709 ;;; result values are specified by the Start and Count as in the
710 ;;; unknown-values continuation representation.
711 ;;; -- If :TAIL, then do a tail-recursive call. No values are returned.
712 ;;; The Old-Fp and Return-PC are passed as the second and third arguments.
713 ;;;
714 ;;; In non-tail calls, the pointer to the stack arguments is passed as
715 ;;; the last fixed argument. If Variable is false, then the passing
716 ;;; locations are passed as a more arg. Variable is true if there are
717 ;;; a variable number of arguments passed on the stack. Variable
718 ;;; cannot be specified with :TAIL return. TR variable argument call
719 ;;; is implemented separately.
720 ;;;
721 ;;; In tail call with fixed arguments, the passing locations are
722 ;;; passed as a more arg, but there is no new-FP, since the arguments
723 ;;; have been set up in the current frame.
729 (:args
751 (:info
755 step-instrumenting)
757 (:ignore
761 ;; We pass either the fdefn object (for named call) or
762 ;; the actual function object (for unnamed call) in
763 ;; EAX. With named call, closure-tramp will replace it
764 ;; with the real function and invoke the real function
765 ;; for closures. Non-closures do not need this value,
766 ;; so don't care what shows up in it.
767 (:temporary
768 (:sc descriptor-reg
769 :offset eax-offset
772 eax)
774 ;; We pass the number of arguments in ECX.
777 ;; With variable call, we have to load the
778 ;; register-args out of the (new) stack frame before
779 ;; doing the call. Therefore, we have to tell the
780 ;; lifetime stuff that we need to use them.
794 old-fp-tmp)))
801 15
804 ;; This has to be done before the frame pointer is
805 ;; changed! EAX stores the 'lexical environment' needed
806 ;; for closures.
811 ;; For variable call, compute the number of
812 ;; arguments and move some of the arguments to
813 ;; registers.
815 ;; Compute the number of arguments.
818 ;; Move the necessary args to registers,
819 ;; this moves them all even if they are
820 ;; not all needed.
823 for index downfrom -1
831 ;; return to so might as well use that clue.
832 ;; This seems really important to the
833 ;; implementation of things like
834 ;; (without-interrupts ...)
835 ;;
836 ;; dtc; Could be doing a tail call from a
837 ;; known-local-call etc in which the old-fp
838 ;; or ret-pc are in regs or in non-standard
839 ;; places. If the passing location were
840 ;; wired to the stack in standard locations
841 ;; then these moves will be un-necessary;
842 ;; this is probably best for the x86.
847 ;; FIXME: FORMAT T for stale
848 ;; diagnostic output (several of
849 ;; them around here), ick
853 ebp-tn
858 ebp-tn
861 ;; For tail call, we have to push the
862 ;; return-pc so that it looks like we CALLed
863 ;; despite the fact that we are going to JMP.
865 ))
867 ;; For non-tail call, we have to save our
868 ;; frame pointer and install the new frame
869 ;; pointer. We can't load stack tns after this
870 ;; point.
872 ;; here which doesn't leave room for the
873 ;; ofp/ret stuff.
875 ;; The variable args are on the stack and
876 ;; become the frame, but there may be <3
877 ;; args and 3 stack slots are assumed
878 ;; allocate on the call. So need to ensure
879 ;; there are at least 3 slots. This hack
880 ;; just adds 3 more.
884 ;; Bias the new-fp for use as an fp
888 ;; Save the fp
893 )))
899 DONE
906 other-pointer-lowtag)
908 fun-pointer-lowtag)))
910 (:fixed
912 (:unknown
915 node)))
928 ;;; This is defined separately, since it needs special code that BLT's
929 ;;; the arguments down. All the real work is done in the assembly
930 ;;; routine. We just set things up so that it can find what it needs.
940 ;; Move these into the passing locations if they are not already there.
943 ;; And jump to the assembly routine.
945 \f
946 ;;;; unknown values return
948 ;;; Return a single-value using the Unknown-Values convention.
949 ;;;
950 ;;; pfw--get wired-tn conflicts sometimes if register sc specd for args
951 ;;; having problems targeting args to regs -- using temps instead.
952 ;;;
953 ;;; First off, modifying the return-pc defeats the branch-prediction
954 ;;; optimizations on modern CPUs quite handily. Second, we can do all
955 ;;; this without needing a temp register. Fixed the latter, at least.
956 ;;; -- AB 2006/Feb/04
964 ;; Drop stack above old-fp
966 ;; Clear the multiple-value return flag
968 ;; Restore the old frame pointer
970 ;; And return.
973 ;;; Do unknown-values return of a fixed (other than 1) number of
974 ;;; values. The VALUES are required to be set up in the standard
975 ;;; passing locations. NVALS is the number of values returned.
976 ;;;
977 ;;; Basically, we just load ECX with the number of values returned and
978 ;;; EBX with a pointer to the values, set ESP to point to the end of
979 ;;; the values, and jump directly to return-pc.
986 ;; In the case of other than one value, we need these registers to
987 ;; tell the caller where they are and how many there are.
990 ;; We need to stretch the lifetime of return-pc past the argument
991 ;; registers so that we can default the argument registers without
992 ;; trashing return-pc.
1003 ;; This is handled in RETURN-SINGLE.
1005 ;; Establish the values pointer and values count.
1011 ;; Pre-default any argument register that need it.
1018 ;; Set the multiple value return flag.
1020 ;; And away we go. Except that return-pc is still on the
1021 ;; stack and we've changed the stack pointer. So we have to
1022 ;; tell it to index off of EBX instead of EBP.
1028 ;; Some values are on the stack after RETURN-PC and OLD-FP,
1029 ;; can't return normally and some slots of the frame will
1030 ;; be used as temporaries by the receiver.
1031 ;;
1032 ;; Clear as much of the stack as possible, but not past the
1033 ;; old frame address.
1044 ;;; Do unknown-values return of an arbitrary number of values (passed
1045 ;;; on the stack.) We check for the common case of a single return
1046 ;;; value, and do that inline using the normal single value return
1047 ;;; convention. Otherwise, we branch off to code that calls an
1048 ;;; assembly-routine.
1049 ;;;
1050 ;;; The assembly routine takes the following args:
1051 ;;; ECX -- number of values to find there.
1052 ;;; ESI -- pointer to where to find the values.
1066 ;; Check for the single case.
1070 ;; Return with one value.
1072 ;; Clear the stack until ocfp.
1074 ;; clear the multiple-value return flag
1076 ;; Out of here.
1079 ;; Nope, not the single case. Jump to the assembly routine.
1084 \f
1085 ;;;; XEP hackery
1087 ;;; Get the lexical environment from its passing location.
1093 ;; Get result.
1096 ;;; Copy a &MORE arg from the argument area to the end of the current
1097 ;;; frame. FIXED is the number of non-&MORE arguments.
1098 ;;;
1099 ;;; The tricky part is doing this without trashing any of the calling
1100 ;;; convention registers that are still needed. This vop is emitted
1101 ;;; directly after the xep-allocate frame. That means the registers
1102 ;;; are in use as follows:
1103 ;;;
1104 ;;; EAX -- The lexenv.
1105 ;;; EBX -- Available.
1106 ;;; ECX -- The total number of arguments * N-WORD-BYTES.
1107 ;;; EDX -- The first arg.
1108 ;;; EDI -- The second arg.
1109 ;;; ESI -- The third arg.
1110 ;;;
1111 ;;; So basically, we have one register available for our use: EBX.
1112 ;;;
1113 ;;; What we can do is push the other regs onto the stack, and then
1114 ;;; restore their values by looking directly below where we put the
1115 ;;; more-args.
1119 ;; Avoid the copy if there are no more args.
1126 ;; Allocate the space on the stack.
1127 ;; stack = ebp + sp->fp-offset - (max 3 frame-size) - (nargs - fixed)
1128 ;;
1129 ;; Problem: this might leave some &more args outside esp, so
1130 ;; clamp the movement for now. If fixed > frame-size, reset
1131 ;; esp to the end of the current &more args (which *should*
1132 ;; be a noop?), and only set esp to its final value after the
1133 ;; stack-stack memmove loop. Otherwise, an unlucky signal
1134 ;; could end up overwriting the &more arguments before they're
1135 ;; moved in their final place.
1142 fixed))))))
1146 ;; Now: nargs>=1 && nargs>fixed
1148 ;; Save the original count of args.
1152 ;; We must stop when we run out of stack args, not when we
1153 ;; run out of more args.
1154 ;; Number to copy = nargs-3
1156 ;; Everything of interest in registers.
1159 ;; Number to copy = nargs-fixed
1164 fixed)))
1167 ;; nothing to move!
1168 )
1170 ;; stack frame smaller than fixed; moving args to higher
1171 ;; addresses (stack grows downard), so copy from the
1172 ;; end. Moreover, because we'd have to shrink the frame,
1173 ;; esp currently points at the end of the source args.
1180 ;; compensate for PUSH above
1184 ;; compensate for PUSH, and
1185 ;; add (abs delta)
1187 ebx-tn)
1192 ;; stack frame larger than fixed. Moving args to lower
1193 ;; addresses, so copy from the lowest address. esp
1194 ;; already points to the lowest address of the destination.
1202 ;; PUSHed 2 words
1204 delta)))
1208 esi-tn)
1215 DO-REGS
1216 ;; stack can now be set to its final size
1222 ;; Restore ECX
1225 ;; Here: nargs>=1 && nargs>fixed
1227 ;; Now we have to deposit any more args that showed up in
1228 ;; registers.
1231 ;; Store it relative to ebp
1245 ;; Don't deposit any more than there are.
1253 JUST-ALLOC-FRAME
1260 DONE))
1307 ;;; Turn more arg (context, count) into a list.
1327 ;; Check to see whether there are no args, and just return NIL if so.
1333 ;; Set decrement mode (successive args at lower addresses)
1335 ;; Set up the result.
1337 ;; Jump into the middle of the loop, 'cause that's where we want
1338 ;; to start.
1341 ;; Compute a pointer to the next cons.
1343 ;; Store a pointer to this cons in the CDR of the previous cons.
1346 ;; Grab one value and stash it in the car of this cons.
1349 ;; Go back for more.
1352 ;; NIL out the last cons.
1357 ;;; Return the location and size of the &MORE arg glob created by
1358 ;;; COPY-MORE-ARG. SUPPLIED is the total number of arguments supplied
1359 ;;; (originally passed in ECX). FIXED is the number of non-rest
1360 ;;; arguments.
1361 ;;;
1362 ;;; We must duplicate some of the work done by COPY-MORE-ARG, since at
1363 ;;; that time the environment is in a pretty brain-damaged state,
1364 ;;; preventing this info from being returned as values. What we do is
1365 ;;; compute supplied - fixed, and return a pointer that many words
1366 ;;; below the current stack top.
1379 ;; SP at this point points at the last arg pushed.
1380 ;; Point to the first more-arg, not above it.
1387 ;;; Signal wrong argument count error if NARGS isn't equal to COUNT.
1417 ;;; Single-stepping
1419 ;; We use different ways of representing whether stepping is on on
1420 ;; +SB-THREAD / -SB-THREAD: on +SB-THREAD, we use a slot in the
1421 ;; thread structure. On -SB-THREAD we use the value of a static
1422 ;; symbol. Things are done this way, since reading a thread-local
1423 ;; slot from a symbol would require an extra register on +SB-THREAD,
1424 ;; and reading a slot from a thread structure would require an extra
1425 ;; register on -SB-THREAD.
1426 #!+sb-thread
1434 #!-sb-thread
1444 DONE