| blob | bc1e06ed6d03a4f7607b7735ab6b84db606790ca |
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.
151 ;;; This is emitted directly before either a known-call-local, call-local,
152 ;;; or a multiple-call-local. All it does is allocate stack space for the
153 ;;; callee (who has the same size stack as us).
164 ;;; Allocate a partial frame for passing stack arguments in a full
165 ;;; call. NARGS is the number of arguments passed. We allocate at
166 ;;; least 3 slots, because the XEP noise is going to want to use them
167 ;;; before it can extend the stack.
175 \f
176 ;;; Emit code needed at the return-point from an unknown-values call
177 ;;; for a fixed number of values. Values is the head of the TN-REF
178 ;;; list for the locations that the values are to be received into.
179 ;;; Nvals is the number of values that are to be received (should
180 ;;; equal the length of Values).
181 ;;;
182 ;;; If 0 or 1 values are expected, then we just emit an instruction to
183 ;;; reset the SP (which will only be executed when other than 1 value
184 ;;; is returned.)
185 ;;;
186 ;;; In the general case we have to do three things:
187 ;;; -- Default unsupplied register values. This need only be done
188 ;;; when a single value is returned, since register values are
189 ;;; defaulted by the called in the non-single case.
190 ;;; -- Default unsupplied stack values. This needs to be done whenever
191 ;;; there are stack values.
192 ;;; -- Reset SP. This must be done whenever other than 1 value is
193 ;;; returned, regardless of the number of values desired.
203 register-arg-count)
206 ;; The function never returns, it may happen that the code
207 ;; ends right here leavig the :SINGLE-VALUE-RETURN note
208 ;; dangling. Let's emit a NOP.
224 ;; Default the unsupplied registers.
232 for count from 2 below register-arg-count
240 ;; The number of bytes depends on the relative jump instructions.
241 ;; Best case is 31+(n-3)*14, worst case is 35+(n-3)*18. For
242 ;; NVALS=6 that is 73/89 bytes, and for NVALS=7 that is 87/107
243 ;; bytes which is likely better than using the blt below.
248 ;; Branch off to the MV case.
250 ;; Do the single value case.
251 ;; Default the register args
257 ;; Fake other registers so it looks like we returned with all the
258 ;; registers filled in.
278 ;; There are stack args so the frame of the callee is
279 ;; still there, save EDX in its first slot temporalily.
294 ;; We are setting the first stack argument to NIL.
295 ;; The callee's stack frame is dead, save EDX by
296 ;; pushing it to the stack, it will end up at same
297 ;; place as in the (STOREW EDX-TN EBX-TN -1) case
298 ;; above.
304 ;; 91 bytes for this branch.
311 ;; Branch off to the MV case.
313 ;; Default the register args, and set up the stack as if we
314 ;; entered the MV return point.
318 ;; Compute a pointer to where to put the [defaulted] stack values.
325 ;; Load EAX with NIL so we can quickly store it, and set up
326 ;; stuff for the loop.
330 ;; Jump into the default loop.
332 ;; The regs are defaulted. We need to copy any stack arguments,
333 ;; and then default the remaining stack arguments.
335 ;; Compute the number of stack arguments, and if it's zero or
336 ;; less, don't copy any stack arguments.
339 ;; Save EDI.
341 ;; Throw away any unwanted args.
346 ;; Save the number of stack values.
348 ;; Compute a pointer to where the stack args go.
352 ;; Save ESI, and compute a pointer to where the args come from.
358 ;; Do the copy.
363 ;; Restore ESI.
365 ;; Now we have to default the remaining args. Find out how many.
368 ;; If none, then just blow out of here.
372 ;; Load EAX with NIL for fast storing.
374 ;; Do the store.
378 ;; Restore EDI, and reset the stack.
384 \f
385 ;;;; unknown values receiving
387 ;;; Emit code needed at the return point for an unknown-values call
388 ;;; for an arbitrary number of values.
389 ;;;
390 ;;; We do the single and non-single cases with no shared code: there
391 ;;; doesn't seem to be any potential overlap, and receiving a single
392 ;;; value is more important efficiency-wise.
393 ;;;
394 ;;; When there is a single value, we just push it on the stack,
395 ;;; returning the old SP and 1.
396 ;;;
397 ;;; When there is a variable number of values, we move all of the
398 ;;; argument registers onto the stack, and return ARGS and NARGS.
399 ;;;
400 ;;; ARGS and NARGS are TNs wired to the named locations. We must
401 ;;; explicitly allocate these TNs, since their lifetimes overlap with
402 ;;; the results start and count. (Also, it's nice to be able to target
403 ;;; them.)
420 ;; The stack frame is burnt and RETurned from if there are no
421 ;; stack values. In this case quickly reallocate sufficient space.
423 register-arg-count)
428 ;; dtc: this writes the registers onto the stack even if they are
429 ;; not needed, only the number specified in ecx are used and have
430 ;; stack allocated to them. No harm is done.
433 for i downfrom -1
442 ;;; VOP that can be inherited by unknown values receivers. The main thing this
443 ;;; handles is allocation of the result temporaries.
447 values-start)
450 nvals)
453 \f
454 ;;;; local call with unknown values convention return
457 #+nil
461 #+nil
473 ;;; Instead of JMPing to TARGET, CALL a trampoline that saves the
474 ;;; return pc and jumps. Although this is an incredibly stupid trick
475 ;;; the paired CALL/RET instructions are a big win.
484 ;;; Non-TR local call for a fixed number of values passed according to
485 ;;; the unknown values convention.
486 ;;;
487 ;;; FP is the frame pointer in install before doing the call.
488 ;;;
489 ;;; NFP would be the number-stack frame pointer if we had a separate
490 ;;; number stack.
491 ;;;
492 ;;; Args are the argument passing locations, which are specified only
493 ;;; to terminate their lifetimes in the caller.
494 ;;;
495 ;;; VALUES are the return value locations (wired to the standard
496 ;;; passing locations). NVALS is the number of values received.
497 ;;;
498 ;;; Save is the save info, which we can ignore since saving has been
499 ;;; done.
500 ;;;
501 ;;; TARGET is a continuation pointing to the start of the called
502 ;;; function.
522 ;;; Non-TR local call for a variable number of return values passed according
523 ;;; to the unknown values convention. The results are the start of the values
524 ;;; glob and the number of values received.
543 \f
544 ;;;; local call with known values return
546 ;;; Non-TR local call with known return locations. Known-value return
547 ;;; works just like argument passing in local call.
548 ;;;
549 ;;; Note: we can't use normal load-tn allocation for the fixed args,
550 ;;; since all registers may be tied up by the more operand. Instead,
551 ;;; we use MAYBE-LOAD-STACK-TN.
569 \f
570 ;;; From Douglas Crosher
571 ;;; Return from known values call. We receive the return locations as
572 ;;; arguments to terminate their lifetimes in the returning function. We
573 ;;; restore FP and CSP and jump to the Return-PC.
585 ;; Zot all of the stack except for the old-fp and return-pc.
590 \f
591 ;;;; full call
592 ;;;
593 ;;; There is something of a cross-product effect with full calls.
594 ;;; Different versions are used depending on whether we know the
595 ;;; number of arguments or the name of the called function, and
596 ;;; whether we want fixed values, unknown values, or a tail call.
597 ;;;
598 ;;; In full call, the arguments are passed creating a partial frame on
599 ;;; the stack top and storing stack arguments into that frame. On
600 ;;; entry to the callee, this partial frame is pointed to by FP.
602 ;;; This macro helps in the definition of full call VOPs by avoiding
603 ;;; code replication in defining the cross-product VOPs.
604 ;;;
605 ;;; NAME is the name of the VOP to define.
606 ;;;
607 ;;; NAMED is true if the first argument is an fdefinition object whose
608 ;;; definition is to be called.
609 ;;;
610 ;;; RETURN is either :FIXED, :UNKNOWN or :TAIL:
611 ;;; -- If :FIXED, then the call is for a fixed number of values, returned in
612 ;;; the standard passing locations (passed as result operands).
613 ;;; -- If :UNKNOWN, then the result values are pushed on the stack, and the
614 ;;; result values are specified by the Start and Count as in the
615 ;;; unknown-values continuation representation.
616 ;;; -- If :TAIL, then do a tail-recursive call. No values are returned.
617 ;;; The Old-Fp and Return-PC are passed as the second and third arguments.
618 ;;;
619 ;;; In non-tail calls, the pointer to the stack arguments is passed as
620 ;;; the last fixed argument. If Variable is false, then the passing
621 ;;; locations are passed as a more arg. Variable is true if there are
622 ;;; a variable number of arguments passed on the stack. Variable
623 ;;; cannot be specified with :TAIL return. TR variable argument call
624 ;;; is implemented separately.
625 ;;;
626 ;;; In tail call with fixed arguments, the passing locations are
627 ;;; passed as a more arg, but there is no new-FP, since the arguments
628 ;;; have been set up in the current frame.
634 (:args
656 (:info
660 step-instrumenting)
662 (:ignore
666 ;; We pass either the fdefn object (for named call) or
667 ;; the actual function object (for unnamed call) in
668 ;; EAX. With named call, closure-tramp will replace it
669 ;; with the real function and invoke the real function
670 ;; for closures. Non-closures do not need this value,
671 ;; so don't care what shows up in it.
672 (:temporary
673 (:sc descriptor-reg
674 :offset eax-offset
677 eax)
679 ;; We pass the number of arguments in ECX.
682 ;; With variable call, we have to load the
683 ;; register-args out of the (new) stack frame before
684 ;; doing the call. Therefore, we have to tell the
685 ;; lifetime stuff that we need to use them.
699 old-fp-tmp)))
706 15
710 ;; This has to be done before the frame pointer is
711 ;; changed! EAX stores the 'lexical environment' needed
712 ;; for closures.
717 ;; For variable call, compute the number of
718 ;; arguments and move some of the arguments to
719 ;; registers.
721 ;; Compute the number of arguments.
724 ;; Move the necessary args to registers,
725 ;; this moves them all even if they are
726 ;; not all needed.
729 for index downfrom -1
737 ;; return to so might as well use that clue.
738 ;; This seems really important to the
739 ;; implementation of things like
740 ;; (without-interrupts ...)
741 ;;
742 ;; dtc; Could be doing a tail call from a
743 ;; known-local-call etc in which the old-fp
744 ;; or ret-pc are in regs or in non-standard
745 ;; places. If the passing location were
746 ;; wired to the stack in standard locations
747 ;; then these moves will be un-necessary;
748 ;; this is probably best for the x86.
753 ;; FIXME: FORMAT T for stale
754 ;; diagnostic output (several of
755 ;; them around here), ick
759 ebp-tn
764 ebp-tn
767 ;; For tail call, we have to push the
768 ;; return-pc so that it looks like we CALLed
769 ;; despite the fact that we are going to JMP.
771 ))
773 ;; For non-tail call, we have to save our
774 ;; frame pointer and install the new frame
775 ;; pointer. We can't load stack tns after this
776 ;; point.
778 ;; here which doesn't leave room for the
779 ;; ofp/ret stuff.
781 ;; The variable args are on the stack and
782 ;; become the frame, but there may be <3
783 ;; args and 3 stack slots are assumed
784 ;; allocate on the call. So need to ensure
785 ;; there are at least 3 slots. This hack
786 ;; just adds 3 more.
790 ;; Bias the new-fp for use as an fp
794 ;; Save the fp
799 )))
805 DONE
812 other-pointer-lowtag)
814 fun-pointer-lowtag)))
816 (:fixed
818 (:unknown
821 node)))
835 ;;; This is defined separately, since it needs special code that BLT's
836 ;;; the arguments down. All the real work is done in the assembly
837 ;;; routine. We just set things up so that it can find what it needs.
847 ;; Move these into the passing locations if they are not already there.
850 ;; And jump to the assembly routine.
852 \f
853 ;;;; unknown values return
855 ;;; Return a single-value using the Unknown-Values convention.
856 ;;;
857 ;;; pfw--get wired-tn conflicts sometimes if register sc specd for args
858 ;;; having problems targeting args to regs -- using temps instead.
859 ;;;
860 ;;; First off, modifying the return-pc defeats the branch-prediction
861 ;;; optimizations on modern CPUs quite handily. Second, we can do all
862 ;;; this without needing a temp register. Fixed the latter, at least.
863 ;;; -- AB 2006/Feb/04
872 ;; Drop stack above old-fp
874 ;; Clear the multiple-value return flag
876 ;; Restore the old frame pointer
878 ;; And return.
881 ;;; Do unknown-values return of a fixed (other than 1) number of
882 ;;; values. The VALUES are required to be set up in the standard
883 ;;; passing locations. NVALS is the number of values returned.
884 ;;;
885 ;;; Basically, we just load ECX with the number of values returned and
886 ;;; EBX with a pointer to the values, set ESP to point to the end of
887 ;;; the values, and jump directly to return-pc.
894 ;; In the case of other than one value, we need these registers to
895 ;; tell the caller where they are and how many there are.
898 ;; We need to stretch the lifetime of return-pc past the argument
899 ;; registers so that we can default the argument registers without
900 ;; trashing return-pc.
911 ;; This is handled in RETURN-SINGLE.
914 ;; Establish the values pointer and values count.
920 ;; Pre-default any argument register that need it.
927 ;; Set the multiple value return flag.
929 ;; And away we go. Except that return-pc is still on the
930 ;; stack and we've changed the stack pointer. So we have to
931 ;; tell it to index off of EBX instead of EBP.
937 ;; Some values are on the stack after RETURN-PC and OLD-FP,
938 ;; can't return normally and some slots of the frame will
939 ;; be used as temporaries by the receiver.
940 ;;
941 ;; Clear as much of the stack as possible, but not past the
942 ;; old frame address.
955 ;;; Do unknown-values return of an arbitrary number of values (passed
956 ;;; on the stack.) We check for the common case of a single return
957 ;;; value, and do that inline using the normal single value return
958 ;;; convention. Otherwise, we branch off to code that calls an
959 ;;; assembly-routine.
960 ;;;
961 ;;; The assembly routine takes the following args:
962 ;;; ECX -- number of values to find there.
963 ;;; ESI -- pointer to where to find the values.
978 ;; Check for the single case.
982 ;; Return with one value.
984 ;; Clear the stack until ocfp.
986 ;; clear the multiple-value return flag
988 ;; Out of here.
991 ;; Nope, not the single case. Jump to the assembly routine.
997 \f
998 ;;;; XEP hackery
1000 ;;; We don't need to do anything special for regular functions.
1005 ;; Don't bother doing anything.
1006 nil))
1008 ;;; Get the lexical environment from its passing location.
1014 ;; Get result.
1017 ;;; Copy a &MORE arg from the argument area to the end of the current
1018 ;;; frame. FIXED is the number of non-&MORE arguments.
1019 ;;;
1020 ;;; The tricky part is doing this without trashing any of the calling
1021 ;;; convention registers that are still needed. This vop is emitted
1022 ;;; directly after the xep-allocate frame. That means the registers
1023 ;;; are in use as follows:
1024 ;;;
1025 ;;; EAX -- The lexenv.
1026 ;;; EBX -- Available.
1027 ;;; ECX -- The total number of arguments * N-WORD-BYTES.
1028 ;;; EDX -- The first arg.
1029 ;;; EDI -- The second arg.
1030 ;;; ESI -- The third arg.
1031 ;;;
1032 ;;; So basically, we have one register available for our use: EBX.
1033 ;;;
1034 ;;; What we can do is push the other regs onto the stack, and then
1035 ;;; restore their values by looking directly below where we put the
1036 ;;; more-args.
1040 ;; Avoid the copy if there are no more args.
1047 ;; Allocate the space on the stack.
1048 ;; stack = ebp + sp->fp-offset - (max 3 frame-size) - (nargs - fixed)
1057 ;; Now: nargs>=1 && nargs>fixed
1059 ;; Save the original count of args.
1063 ;; We must stop when we run out of stack args, not when we
1064 ;; run out of more args.
1065 ;; Number to copy = nargs-3
1067 ;; Everything of interest in registers.
1070 ;; Number to copy = nargs-fixed
1073 ;; Save edi and esi register args.
1077 ;; Okay, we have pushed the register args. We can trash them
1078 ;; now.
1080 ;; Initialize src to be end of args.
1085 ;; We need to copy from downwards up to avoid overwriting some of
1086 ;; the yet uncopied args. So we need to use EBX as the copy index
1087 ;; and ECX as the loop counter, rather than using ECX for both.
1090 ;; We used to use REP MOVS here, but on modern x86 it performs
1091 ;; much worse than an explicit loop for small blocks.
1092 COPY-LOOP
1094 ;; The :DISP is to account for the registers saved on the stack
1097 edi-tn)
1102 ;; So now we need to restore EDI and ESI.
1107 DO-REGS
1109 ;; Restore ECX
1112 ;; Here: nargs>=1 && nargs>fixed
1114 ;; Now we have to deposit any more args that showed up in
1115 ;; registers.
1118 ;; Store it relative to ebp
1132 ;; Don't deposit any more than there are.
1140 JUST-ALLOC-FRAME
1147 DONE))
1182 ;;; Turn more arg (context, count) into a list.
1202 ;; Check to see whether there are no args, and just return NIL if so.
1208 ;; Set decrement mode (successive args at lower addresses)
1210 ;; Set up the result.
1212 ;; Jump into the middle of the loop, 'cause that's where we want
1213 ;; to start.
1216 ;; Compute a pointer to the next cons.
1218 ;; Store a pointer to this cons in the CDR of the previous cons.
1221 ;; Grab one value and stash it in the car of this cons.
1224 ;; Go back for more.
1227 ;; NIL out the last cons.
1232 ;;; Return the location and size of the &MORE arg glob created by
1233 ;;; COPY-MORE-ARG. SUPPLIED is the total number of arguments supplied
1234 ;;; (originally passed in ECX). FIXED is the number of non-rest
1235 ;;; arguments.
1236 ;;;
1237 ;;; We must duplicate some of the work done by COPY-MORE-ARG, since at
1238 ;;; that time the environment is in a pretty brain-damaged state,
1239 ;;; preventing this info from being returned as values. What we do is
1240 ;;; compute supplied - fixed, and return a pointer that many words
1241 ;;; below the current stack top.
1254 ;; SP at this point points at the last arg pushed.
1255 ;; Point to the first more-arg, not above it.
1262 ;;; Signal wrong argument count error if NARGS isn't equal to COUNT.
1279 ;;; Various other error signallers.
1287 args))
1295 object type)
1297 object layout)
1304 ;;; Single-stepping
1307 ;; We use different ways of representing whether stepping is on on
1308 ;; +SB-THREAD / -SB-THREAD: on +SB-THREAD, we use a slot in the
1309 ;; thread structure. On -SB-THREAD we use the value of a static
1310 ;; symbol. Things are done this way, since reading a thread-local
1311 ;; slot from a symbol would require an extra register on +SB-THREAD,
1312 ;; and reading a slot from a thread structure would require an extra
1313 ;; register on -SB-THREAD.
1314 #!+sb-thread
1319 #!-sb-thread
1321 nil-value))
1330 DONE