| blob | 10feb3458f86c9661095b9b075cb4a4de1efbf81 |
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.
13 \f
14 ;;;; interfaces to IR2 conversion
16 ;;; Return a wired TN describing the N'th full call argument passing
17 ;;; location.
25 ;;; Make a passing location TN for a local call return PC.
26 ;;;
27 ;;; Always wire the return PC location to the stack in its standard
28 ;;; location.
32 sap-stack-sc-number return-pc-save-offset))
34 ;;; This is similar to MAKE-RETURN-PC-PASSING-LOCATION, but makes a
35 ;;; location to pass OLD-FP in.
36 ;;;
37 ;;; This is wired in both the standard and the local-call conventions,
38 ;;; because we want to be able to assume it's always there. Besides,
39 ;;; the x86 doesn't have enough registers to really make it profitable
40 ;;; to pass it in a register.
44 ocfp-save-offset))
46 ;;; Make the TNs used to hold OLD-FP and RETURN-PC within the current
47 ;;; function. We treat these specially so that the debugger can find
48 ;;; them at a known location.
49 ;;;
50 ;;; Without using a save-tn - which does not make much sense if it is
51 ;;; wired to the stack?
54 control-stack-sc-number
55 ocfp-save-offset)
56 physenv))
60 sap-stack-sc-number return-pc-save-offset)
61 physenv))
63 ;;; Make a TN for the standard argument count passing location. We only
64 ;;; need to make the standard location, since a count is never passed when we
65 ;;; are using non-standard conventions.
69 ;;; Make a TN to hold the number-stack frame pointer. This is allocated
70 ;;; once per component, and is component-live.
80 ;;; Return a list of TNs that can be used to represent an unknown-values
81 ;;; continuation within a function.
86 ;;; This function is called by the ENTRY-ANALYZE phase, allowing
87 ;;; VM-dependent initialization of the IR2-COMPONENT structure. We
88 ;;; push placeholder entries in the CONSTANTS to leave room for
89 ;;; additional noise in the code object header.
92 ;; The 1+ here is because for the x86 the first constant is a
93 ;; pointer to a list of fixups, or NIL if the code object has none.
94 ;; (If I understand correctly, the fixups are needed at GC copy
95 ;; time because the X86 code isn't relocatable.)
96 ;;
97 ;; KLUDGE: It'd be cleaner to have the fixups entry be a named
98 ;; element of the CODE (aka component) primitive object. However,
99 ;; it's currently a large, tricky, error-prone chore to change
100 ;; the layout of any primitive object, so for the foreseeable future
101 ;; we'll just live with this ugliness. -- WHN 2002-01-02
106 \f
107 ;;;; frame hackery
109 ;;; This is used for setting up the Old-FP in local call.
115 ;;; We don't have a separate NFP, so we don't need to do anything here.
120 nil))
129 ;; Skip space for the function header.
134 ;; The start of the actual code.
135 ;; Save the return-pc.
138 ;; If copy-more-arg follows it will allocate the correct stack
139 ;; size. The stack is not allocated first here as this may expose
140 ;; args on the stack if they take up more space than the frame!
142 ;; The args fit within the frame so just allocate the frame.
150 ;;; This is emitted directly before either a known-call-local, call-local,
151 ;;; or a multiple-call-local. All it does is allocate stack space for the
152 ;;; callee (who has the same size stack as us).
162 ;;; Allocate a partial frame for passing stack arguments in a full
163 ;;; call. NARGS is the number of arguments passed. We allocate at
164 ;;; least 3 slots, because the XEP noise is going to want to use them
165 ;;; before it can extend the stack.
172 \f
173 ;;; Emit code needed at the return-point from an unknown-values call
174 ;;; for a fixed number of values. Values is the head of the TN-REF
175 ;;; list for the locations that the values are to be received into.
176 ;;; Nvals is the number of values that are to be received (should
177 ;;; equal the length of Values).
178 ;;;
179 ;;; MOVE-TEMP is a DESCRIPTOR-REG TN used as a temporary.
180 ;;;
181 ;;; This code exploits the fact that in the unknown-values convention,
182 ;;; a single value return returns at the return PC + 2, whereas a
183 ;;; return of other than one value returns directly at the return PC.
184 ;;;
185 ;;; If 0 or 1 values are expected, then we just emit an instruction to
186 ;;; reset the SP (which will only be executed when other than 1 value
187 ;;; is returned.)
188 ;;;
189 ;;; In the general case we have to do three things:
190 ;;; -- Default unsupplied register values. This need only be done
191 ;;; when a single value is returned, since register values are
192 ;;; defaulted by the called in the non-single case.
193 ;;; -- Default unsupplied stack values. This needs to be done whenever
194 ;;; there are stack values.
195 ;;; -- Reset SP. This must be done whenever other than 1 value is
196 ;;; returned, regardless of the number of values desired.
208 ;; Default the unsuppled registers.
216 for count from 2 below register-arg-count
222 ;; The number of bytes depends on the relative jump instructions.
223 ;; Best case is 31+(n-3)*14, worst case is 35+(n-3)*18. For
224 ;; NVALS=6 that is 73/89 bytes, and for NVALS=7 that is 87/107
225 ;; bytes which is likely better than using the blt below.
230 ;; Branch off to the MV case.
232 ;; Do the single value case.
233 ;; Default the register args
240 ;; Fake other registers so it looks like we returned with all the
241 ;; registers filled in.
281 ;; 91 bytes for this branch.
288 ;; Branch off to the MV case.
291 ;; Default the register args, and set up the stack as if we
292 ;; entered the MV return point.
298 ;; Compute a pointer to where to put the [defaulted] stack values.
303 ;; Load EAX with NIL so we can quickly store it, and set up
304 ;; stuff for the loop.
308 ;; Jump into the default loop.
311 ;; The regs are defaulted. We need to copy any stack arguments,
312 ;; and then default the remaining stack arguments.
314 ;; Save EDI.
316 ;; Compute the number of stack arguments, and if it's zero or
317 ;; less, don't copy any stack arguments.
321 ;; Throw away any unwanted args.
326 ;; Save the number of stack values.
328 ;; Compute a pointer to where the stack args go.
332 ;; Save ESI, and compute a pointer to where the args come from.
337 ;; Do the copy.
342 ;; Restore ESI.
344 ;; Now we have to default the remaining args. Find out how many.
347 ;; If none, then just blow out of here.
351 ;; Load EAX with NIL for fast storing.
353 ;; Do the store.
357 ;; Restore EDI, and reset the stack.
362 \f
363 ;;;; unknown values receiving
365 ;;; Emit code needed at the return point for an unknown-values call
366 ;;; for an arbitrary number of values.
367 ;;;
368 ;;; We do the single and non-single cases with no shared code: there
369 ;;; doesn't seem to be any potential overlap, and receiving a single
370 ;;; value is more important efficiency-wise.
371 ;;;
372 ;;; When there is a single value, we just push it on the stack,
373 ;;; returning the old SP and 1.
374 ;;;
375 ;;; When there is a variable number of values, we move all of the
376 ;;; argument registers onto the stack, and return ARGS and NARGS.
377 ;;;
378 ;;; ARGS and NARGS are TNs wired to the named locations. We must
379 ;;; explicitly allocate these TNs, since their lifetimes overlap with
380 ;;; the results start and count. (Also, it's nice to be able to target
381 ;;; them.)
397 ;; dtc: this writes the registers onto the stack even if they are
398 ;; not needed, only the number specified in ecx are used and have
399 ;; stack allocated to them. No harm is done.
402 for i downfrom -1
410 ;;; VOP that can be inherited by unknown values receivers. The main thing this
411 ;;; handles is allocation of the result temporaries.
415 values-start)
418 nvals)
421 \f
422 ;;;; local call with unknown values convention return
424 ;;; Non-TR local call for a fixed number of values passed according to
425 ;;; the unknown values convention.
426 ;;;
427 ;;; FP is the frame pointer in install before doing the call.
428 ;;;
429 ;;; NFP would be the number-stack frame pointer if we had a separate
430 ;;; number stack.
431 ;;;
432 ;;; Args are the argument passing locations, which are specified only
433 ;;; to terminate their lifetimes in the caller.
434 ;;;
435 ;;; VALUES are the return value locations (wired to the standard
436 ;;; passing locations). NVALS is the number of values received.
437 ;;;
438 ;;; Save is the save info, which we can ignore since saving has been
439 ;;; done.
440 ;;;
441 ;;; TARGET is a continuation pointing to the start of the called
442 ;;; function.
458 #+nil
463 ;; Is the return-pc on the stack or in a register?
475 RETURN
479 ;;; Non-TR local call for a variable number of return values passed according
480 ;;; to the unknown values convention. The results are the start of the values
481 ;;; glob and the number of values received.
496 #+nil
501 ;; Is the return-pc on the stack or in a register?
506 ;; Stack
510 ;; Register
515 RETURN
519 \f
520 ;;;; local call with known values return
522 ;;; Non-TR local call with known return locations. Known-value return
523 ;;; works just like argument passing in local call.
524 ;;;
525 ;;; Note: we can't use normal load-tn allocation for the fixed args,
526 ;;; since all registers may be tied up by the more operand. Instead,
527 ;;; we use MAYBE-LOAD-STACK-TN.
544 #+nil
549 ;; Is the return-pc on the stack or in a register?
554 ;; Stack
558 ;; Register
563 RETURN
566 \f
567 ;;; Return from known values call. We receive the return locations as
568 ;;; arguments to terminate their lifetimes in the returning function. We
569 ;;; restore FP and CSP and jump to the Return-PC.
570 ;;;
571 ;;; We can assume we know exactly where old-fp and return-pc are because
572 ;;; make-old-fp-save-location and make-return-pc-save-location always
573 ;;; return the same place.
574 #+nil
586 ;; Save the return-pc in a register 'cause the frame-pointer is
587 ;; going away. Note this not in the usual stack location so we
588 ;; can't use RET
590 ;; Restore the stack.
592 ;; Restore the old fp. We know OLD-FP is going to be in its stack
593 ;; save slot, which is a different frame that than this one,
594 ;; so we don't have to worry about having just cleared
595 ;; most of the stack.
599 \f
600 ;;; From Douglas Crosher
601 ;;; Return from known values call. We receive the return locations as
602 ;;; arguments to terminate their lifetimes in the returning function. We
603 ;;; restore FP and CSP and jump to the Return-PC.
604 ;;;
605 ;;; The old-fp may be either in a register or on the stack in its
606 ;;; standard save locations - slot 0.
607 ;;;
608 ;;; The return-pc may be in a register or on the stack in any slot.
629 ;; return-pc may be either in a register or on the stack.
639 ;; Zot all of the stack except for the old-fp.
642 n-word-bytes))))
643 ;; Restore the old fp from its save location on the stack,
644 ;; and zot the stack.
649 "VOP return-local doesn't work if old-fp (in slot ~
650 ~S) is not in slot 0"
654 ;; Zot all the stack.
656 ;; Restore the old-fp.
659 ;; Return; return-pc is in a register.
667 ;; Zot all of the stack except for the old-fp and return-pc.
671 ;; Restore the old fp. old-fp may be either on the stack in its
672 ;; save location or in a register, in either case this restores it.
674 ;; The return pops the return address (4 bytes), then we need
675 ;; to pop all the slots before the return-pc which includes the
676 ;; 4 bytes for the old-fp.
680 \f
681 ;;;; full call
682 ;;;
683 ;;; There is something of a cross-product effect with full calls.
684 ;;; Different versions are used depending on whether we know the
685 ;;; number of arguments or the name of the called function, and
686 ;;; whether we want fixed values, unknown values, or a tail call.
687 ;;;
688 ;;; In full call, the arguments are passed creating a partial frame on
689 ;;; the stack top and storing stack arguments into that frame. On
690 ;;; entry to the callee, this partial frame is pointed to by FP.
692 ;;; This macro helps in the definition of full call VOPs by avoiding
693 ;;; code replication in defining the cross-product VOPs.
694 ;;;
695 ;;; NAME is the name of the VOP to define.
696 ;;;
697 ;;; NAMED is true if the first argument is an fdefinition object whose
698 ;;; definition is to be called.
699 ;;;
700 ;;; RETURN is either :FIXED, :UNKNOWN or :TAIL:
701 ;;; -- If :FIXED, then the call is for a fixed number of values, returned in
702 ;;; the standard passing locations (passed as result operands).
703 ;;; -- If :UNKNOWN, then the result values are pushed on the stack, and the
704 ;;; result values are specified by the Start and Count as in the
705 ;;; unknown-values continuation representation.
706 ;;; -- If :TAIL, then do a tail-recursive call. No values are returned.
707 ;;; The Old-Fp and Return-PC are passed as the second and third arguments.
708 ;;;
709 ;;; In non-tail calls, the pointer to the stack arguments is passed as
710 ;;; the last fixed argument. If Variable is false, then the passing
711 ;;; locations are passed as a more arg. Variable is true if there are
712 ;;; a variable number of arguments passed on the stack. Variable
713 ;;; cannot be specified with :TAIL return. TR variable argument call
714 ;;; is implemented separately.
715 ;;;
716 ;;; In tail call with fixed arguments, the passing locations are
717 ;;; passed as a more arg, but there is no new-FP, since the arguments
718 ;;; have been set up in the current frame.
724 (:args
746 (:info
751 (:ignore
755 ;; We pass either the fdefn object (for named call) or
756 ;; the actual function object (for unnamed call) in
757 ;; EAX. With named call, closure-tramp will replace it
758 ;; with the real function and invoke the real function
759 ;; for closures. Non-closures do not need this value,
760 ;; so don't care what shows up in it.
761 (:temporary
762 (:sc descriptor-reg
763 :offset eax-offset
766 eax)
768 ;; We pass the number of arguments in ECX.
771 ;; With variable call, we have to load the
772 ;; register-args out of the (new) stack frame before
773 ;; doing the call. Therefore, we have to tell the
774 ;; lifetime stuff that we need to use them.
788 old-fp-tmp)))
793 15
797 ;; This has to be done before the frame pointer is
798 ;; changed! EAX stores the 'lexical environment' needed
799 ;; for closures.
804 ;; For variable call, compute the number of
805 ;; arguments and move some of the arguments to
806 ;; registers.
808 ;; Compute the number of arguments.
811 ;; Move the necessary args to registers,
812 ;; this moves them all even if they are
813 ;; not all needed.
816 for index downfrom -1
824 ;; return to so might as well use that clue.
825 ;; This seems really important to the
826 ;; implementation of things like
827 ;; (without-interrupts ...)
828 ;;
829 ;; dtc; Could be doing a tail call from a
830 ;; known-local-call etc in which the old-fp
831 ;; or ret-pc are in regs or in non-standard
832 ;; places. If the passing location were
833 ;; wired to the stack in standard locations
834 ;; then these moves will be un-necessary;
835 ;; this is probably best for the x86.
840 ;; FIXME: FORMAT T for stale
841 ;; diagnostic output (several of
842 ;; them around here), ick
846 ebp-tn
851 ebp-tn
854 ;; For tail call, we have to push the
855 ;; return-pc so that it looks like we CALLed
856 ;; despite the fact that we are going to JMP.
858 ))
860 ;; For non-tail call, we have to save our
861 ;; frame pointer and install the new frame
862 ;; pointer. We can't load stack tns after this
863 ;; point.
865 ;; here which doesn't leave room for the
866 ;; ofp/ret stuff.
868 ;; The variable args are on the stack and
869 ;; become the frame, but there may be <3
870 ;; args and 3 stack slots are assumed
871 ;; allocate on the call. So need to ensure
872 ;; there are at least 3 slots. This hack
873 ;; just adds 3 more.
877 ;; Save the fp
881 )))
889 n-word-bytes)
890 other-pointer-lowtag)
892 fun-pointer-lowtag))))
894 (:fixed
896 (:unknown
912 ;;; This is defined separately, since it needs special code that BLT's
913 ;;; the arguments down. All the real work is done in the assembly
914 ;;; routine. We just set things up so that it can find what it needs.
922 ; (:ignore ret-addr old-fp)
924 ;; Move these into the passing locations if they are not already there.
928 ;; The following assumes that the return-pc and old-fp are on the
929 ;; stack in their standard save locations - Check this.
938 ;; And jump to the assembly routine.
940 \f
941 ;;;; unknown values return
943 ;;; Return a single-value using the Unknown-Values convention. Specifically,
944 ;;; we jump to clear the stack and jump to return-pc+2.
945 ;;;
946 ;;; We require old-fp to be in a register, because we want to reset ESP before
947 ;;; restoring EBP. If old-fp were still on the stack, it could get clobbered
948 ;;; by a signal.
949 ;;;
950 ;;; pfw--get wired-tn conflicts sometimes if register sc specd for args
951 ;;; having problems targeting args to regs -- using temps instead.
962 ;; Clear the control stack
964 ;; Adjust the return address for the single value return.
966 ;; Restore the frame pointer.
969 ;; Out of here.
972 ;;; Do unknown-values return of a fixed (other than 1) number of
973 ;;; values. The VALUES are required to be set up in the standard
974 ;;; passing locations. NVALS is the number of values returned.
975 ;;;
976 ;;; Basically, we just load ECX with the number of values returned and
977 ;;; EBX with a pointer to the values, set ESP to point to the end of
978 ;;; 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.
991 ;; We need to stretch the lifetime of return-pc past the argument
992 ;; registers so that we can default the argument registers without
993 ;; trashing return-pc.
1003 ;; Establish the values pointer and values count.
1008 ;; Restore the frame pointer.
1010 ;; Clear as much of the stack as possible, but not past the return
1011 ;; address.
1014 ;; Pre-default any argument register that need it.
1021 ;; And away we go. Except that return-pc is still on the
1022 ;; stack and we've changed the stack pointer. So we have to
1023 ;; tell it to index off of EBX instead of EBP.
1025 ;; Return popping the return address and the OCFP.
1028 ;; Return popping the return, leaving 1 slot. Can this
1029 ;; happen, or is a single value return handled elsewhere?
1034 n-word-bytes))))))
1038 ;;; Do unknown-values return of an arbitrary number of values (passed
1039 ;;; on the stack.) We check for the common case of a single return
1040 ;;; value, and do that inline using the normal single value return
1041 ;;; convention. Otherwise, we branch off to code that calls an
1042 ;;; assembly-routine.
1043 ;;;
1044 ;;; The assembly routine takes the following args:
1045 ;;; EAX -- the return-pc to finally jump to.
1046 ;;; EBX -- pointer to where to put the values.
1047 ;;; ECX -- number of values to find there.
1048 ;;; ESI -- pointer to where to find the values.
1066 ;; Load the return-pc.
1069 ;; Check for the single case.
1074 ;; Return with one value.
1076 ;; Clear the stack. We load old-fp into a register before clearing
1077 ;; the stack.
1081 ;; Fix the return-pc to point at the single-value entry point.
1083 ;; Out of here.
1086 ;; Nope, not the single case. Jump to the assembly routine.
1094 \f
1095 ;;;; XEP hackery
1097 ;;; We don't need to do anything special for regular functions.
1102 ;; Don't bother doing anything.
1103 nil))
1105 ;;; Get the lexical environment from its passing location.
1111 ;; Get result.
1114 ;;; Copy a &MORE arg from the argument area to the end of the current
1115 ;;; frame. FIXED is the number of non-&MORE arguments.
1116 ;;;
1117 ;;; The tricky part is doing this without trashing any of the calling
1118 ;;; convention registers that are still needed. This vop is emitted
1119 ;;; directly after the xep-allocate frame. That means the registers
1120 ;;; are in use as follows:
1121 ;;;
1122 ;;; EAX -- The lexenv.
1123 ;;; EBX -- Available.
1124 ;;; ECX -- The total number of arguments.
1125 ;;; EDX -- The first arg.
1126 ;;; EDI -- The second arg.
1127 ;;; ESI -- The third arg.
1128 ;;;
1129 ;;; So basically, we have one register available for our use: EBX.
1130 ;;;
1131 ;;; What we can do is push the other regs onto the stack, and then
1132 ;;; restore their values by looking directly below where we put the
1133 ;;; more-args.
1137 ;; Avoid the copy if there are no more args.
1144 ;; Allocate the space on the stack.
1145 ;; stack = ebp - (max 3 frame-size) - (nargs - fixed)
1149 (* n-word-bytes
1154 ;; Now: nargs>=1 && nargs>fixed
1156 ;; Save the original count of args.
1160 ;; We must stop when we run out of stack args, not when we
1161 ;; run out of more args.
1162 ;; Number to copy = nargs-3
1164 ;; Everything of interest in registers.
1167 ;; Number to copy = nargs-fixed
1170 ;; Save edi and esi register args.
1173 ;; Okay, we have pushed the register args. We can trash them
1174 ;; now.
1176 ;; Initialize dst to be end of stack; skiping the values pushed
1177 ;; above.
1180 ;; Initialize src to be end of args.
1185 ;; And copy the args.
1190 ;; So now we need to restore EDI and ESI.
1194 DO-REGS
1196 ;; Restore ECX
1199 ;; Here: nargs>=1 && nargs>fixed
1201 ;; Now we have to deposit any more args that showed up in
1202 ;; registers.
1205 ;; Store it relative to ebp
1216 ;; Don't deposit any more than there are.
1224 JUST-ALLOC-FRAME
1230 DONE))
1232 ;;; &MORE args are stored contiguously on the stack, starting
1233 ;;; immediately at the context pointer. The context pointer is not
1234 ;;; typed, so the lowtag is 0.
1262 ;;; Turn more arg (context, count) into a list.
1264 t)
1285 ;; Check to see whether there are no args, and just return NIL if so.
1292 ;; Convert the count into a raw value, so that we can use the
1293 ;; LOOP instruction.
1295 ;; Set decrement mode (successive args at lower addresses)
1297 ;; Set up the result.
1299 ;; Jump into the middle of the loop, 'cause that's were we want
1300 ;; to start.
1303 ;; Compute a pointer to the next cons.
1305 ;; Store a pointer to this cons in the CDR of the previous cons.
1308 ;; Grab one value and stash it in the car of this cons.
1311 ;; Go back for more.
1313 ;; NIL out the last cons.
1317 ;;; Return the location and size of the &MORE arg glob created by
1318 ;;; COPY-MORE-ARG. SUPPLIED is the total number of arguments supplied
1319 ;;; (originally passed in ECX). FIXED is the number of non-rest
1320 ;;; arguments.
1321 ;;;
1322 ;;; We must duplicate some of the work done by COPY-MORE-ARG, since at
1323 ;;; that time the environment is in a pretty brain-damaged state,
1324 ;;; preventing this info from being returned as values. What we do is
1325 ;;; compute supplied - fixed, and return a pointer that many words
1326 ;;; below the current stack top.
1339 ;; SP at this point points at the last arg pushed.
1340 ;; Point to the first more-arg, not above it.
1347 ;;; Signal wrong argument count error if NARGS isn't equal to COUNT.
1364 ;;; Various other error signallers.
1372 args))
1380 object type)
1382 object layout)