| blob | b57642ae68bae7d0cbb110aa18b71f69e5da4929 |
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.
219 ;; Default the unsupplied registers.
227 for count from 2 below register-arg-count
235 ;; The number of bytes depends on the relative jump instructions.
236 ;; Best case is 31+(n-3)*14, worst case is 35+(n-3)*18. For
237 ;; NVALS=6 that is 73/89 bytes, and for NVALS=7 that is 87/107
238 ;; bytes which is likely better than using the blt below.
243 ;; Branch off to the MV case.
245 ;; Do the single value case.
246 ;; Default the register args
252 ;; Fake other registers so it looks like we returned with all the
253 ;; registers filled in.
273 ;; There are stack args so the frame of the callee is
274 ;; still there, save RDX in its first slot temporalily.
289 ;; We are setting the first stack argument to NIL.
290 ;; The callee's stack frame is dead, save RDX by
291 ;; pushing it to the stack, it will end up at same
292 ;; place as in the (STOREW RDX-TN RBX-TN -1) case
293 ;; above.
305 ;; Branch off to the MV case.
307 ;; Default the register args, and set up the stack as if we
308 ;; entered the MV return point.
312 ;; Compute a pointer to where to put the [defaulted] stack values.
319 ;; Load RAX with NIL so we can quickly store it, and set up
320 ;; stuff for the loop.
324 ;; Jump into the default loop.
326 ;; The regs are defaulted. We need to copy any stack arguments,
327 ;; and then default the remaining stack arguments.
329 ;; Compute the number of stack arguments, and if it's zero or
330 ;; less, don't copy any stack arguments.
333 ;; Save EDI.
335 ;; Throw away any unwanted args.
340 ;; Save the number of stack values.
342 ;; Compute a pointer to where the stack args go.
346 ;; Save ESI, and compute a pointer to where the args come from.
352 ;; Do the copy.
357 ;; Restore RSI.
359 ;; Now we have to default the remaining args. Find out how many.
362 ;; If none, then just blow out of here.
366 ;; Load RAX with NIL for fast storing.
368 ;; Do the store.
372 ;; Restore EDI, and reset the stack.
378 \f
379 ;;;; unknown values receiving
381 ;;; Emit code needed at the return point for an unknown-values call
382 ;;; for an arbitrary number of values.
383 ;;;
384 ;;; We do the single and non-single cases with no shared code: there
385 ;;; doesn't seem to be any potential overlap, and receiving a single
386 ;;; value is more important efficiency-wise.
387 ;;;
388 ;;; When there is a single value, we just push it on the stack,
389 ;;; returning the old SP and 1.
390 ;;;
391 ;;; When there is a variable number of values, we move all of the
392 ;;; argument registers onto the stack, and return ARGS and NARGS.
393 ;;;
394 ;;; ARGS and NARGS are TNs wired to the named locations. We must
395 ;;; explicitly allocate these TNs, since their lifetimes overlap with
396 ;;; the results start and count. (Also, it's nice to be able to target
397 ;;; them.)
414 ;; The stack frame is burnt and RETurned from if there are no
415 ;; stack values. In this case quickly reallocate sufficient space.
417 register-arg-count)
422 ;; dtc: this writes the registers onto the stack even if they are
423 ;; not needed, only the number specified in rcx are used and have
424 ;; stack allocated to them. No harm is done.
427 for i downfrom -1
436 ;;; VOP that can be inherited by unknown values receivers. The main thing this
437 ;;; handles is allocation of the result temporaries.
441 values-start)
444 nvals)
447 \f
448 ;;;; local call with unknown values convention return
451 #+nil
455 #+nil
467 ;;; Instead of JMPing to TARGET, CALL a trampoline that saves the
468 ;;; return pc and jumps. Although this is an incredibly stupid trick
469 ;;; the paired CALL/RET instructions are a big win.
478 ;;; Non-TR local call for a fixed number of values passed according to
479 ;;; the unknown values convention.
480 ;;;
481 ;;; FP is the frame pointer in install before doing the call.
482 ;;;
483 ;;; NFP would be the number-stack frame pointer if we had a separate
484 ;;; number stack.
485 ;;;
486 ;;; Args are the argument passing locations, which are specified only
487 ;;; to terminate their lifetimes in the caller.
488 ;;;
489 ;;; VALUES are the return value locations (wired to the standard
490 ;;; passing locations). NVALS is the number of values received.
491 ;;;
492 ;;; Save is the save info, which we can ignore since saving has been
493 ;;; done.
494 ;;;
495 ;;; TARGET is a continuation pointing to the start of the called
496 ;;; function.
516 ;;; Non-TR local call for a variable number of return values passed according
517 ;;; to the unknown values convention. The results are the start of the values
518 ;;; glob and the number of values received.
537 \f
538 ;;;; local call with known values return
540 ;;; Non-TR local call with known return locations. Known-value return
541 ;;; works just like argument passing in local call.
542 ;;;
543 ;;; Note: we can't use normal load-tn allocation for the fixed args,
544 ;;; since all registers may be tied up by the more operand. Instead,
545 ;;; we use MAYBE-LOAD-STACK-TN.
563 \f
564 ;;; From Douglas Crosher
565 ;;; Return from known values call. We receive the return locations as
566 ;;; arguments to terminate their lifetimes in the returning function. We
567 ;;; restore FP and CSP and jump to the Return-PC.
579 ;; Zot all of the stack except for the old-fp and return-pc.
584 \f
585 ;;;; full call
586 ;;;
587 ;;; There is something of a cross-product effect with full calls.
588 ;;; Different versions are used depending on whether we know the
589 ;;; number of arguments or the name of the called function, and
590 ;;; whether we want fixed values, unknown values, or a tail call.
591 ;;;
592 ;;; In full call, the arguments are passed creating a partial frame on
593 ;;; the stack top and storing stack arguments into that frame. On
594 ;;; entry to the callee, this partial frame is pointed to by FP.
596 ;;; This macro helps in the definition of full call VOPs by avoiding
597 ;;; code replication in defining the cross-product VOPs.
598 ;;;
599 ;;; NAME is the name of the VOP to define.
600 ;;;
601 ;;; NAMED is true if the first argument is an fdefinition object whose
602 ;;; definition is to be called.
603 ;;;
604 ;;; RETURN is either :FIXED, :UNKNOWN or :TAIL:
605 ;;; -- If :FIXED, then the call is for a fixed number of values, returned in
606 ;;; the standard passing locations (passed as result operands).
607 ;;; -- If :UNKNOWN, then the result values are pushed on the stack, and the
608 ;;; result values are specified by the Start and Count as in the
609 ;;; unknown-values continuation representation.
610 ;;; -- If :TAIL, then do a tail-recursive call. No values are returned.
611 ;;; The Old-Fp and Return-PC are passed as the second and third arguments.
612 ;;;
613 ;;; In non-tail calls, the pointer to the stack arguments is passed as
614 ;;; the last fixed argument. If Variable is false, then the passing
615 ;;; locations are passed as a more arg. Variable is true if there are
616 ;;; a variable number of arguments passed on the stack. Variable
617 ;;; cannot be specified with :TAIL return. TR variable argument call
618 ;;; is implemented separately.
619 ;;;
620 ;;; In tail call with fixed arguments, the passing locations are
621 ;;; passed as a more arg, but there is no new-FP, since the arguments
622 ;;; have been set up in the current frame.
628 (:args
650 (:info
654 step-instrumenting)
656 (:ignore
660 ;; We pass either the fdefn object (for named call) or
661 ;; the actual function object (for unnamed call) in
662 ;; RAX. With named call, closure-tramp will replace it
663 ;; with the real function and invoke the real function
664 ;; for closures. Non-closures do not need this value,
665 ;; so don't care what shows up in it.
666 (:temporary
667 (:sc descriptor-reg
668 :offset rax-offset
671 rax)
673 ;; We pass the number of arguments in RCX.
676 ;; With variable call, we have to load the
677 ;; register-args out of the (new) stack frame before
678 ;; doing the call. Therefore, we have to tell the
679 ;; lifetime stuff that we need to use them.
693 old-fp-tmp)))
700 15
704 ;; This has to be done before the frame pointer is
705 ;; changed! RAX stores the 'lexical environment' needed
706 ;; for closures.
711 ;; For variable call, compute the number of
712 ;; arguments and move some of the arguments to
713 ;; registers.
715 ;; Compute the number of arguments.
718 ;; Move the necessary args to registers,
719 ;; this moves them all even if they are
720 ;; not all needed.
723 for index downfrom -1
731 ;; return to so might as well use that clue.
732 ;; This seems really important to the
733 ;; implementation of things like
734 ;; (without-interrupts ...)
735 ;;
736 ;; dtc; Could be doing a tail call from a
737 ;; known-local-call etc in which the old-fp
738 ;; or ret-pc are in regs or in non-standard
739 ;; places. If the passing location were
740 ;; wired to the stack in standard locations
741 ;; then these moves will be un-necessary;
742 ;; this is probably best for the x86.
747 ;; FIXME: FORMAT T for stale
748 ;; diagnostic output (several of
749 ;; them around here), ick
753 rbp-tn
758 rbp-tn
761 ;; For tail call, we have to push the
762 ;; return-pc so that it looks like we CALLed
763 ;; despite the fact that we are going to JMP.
765 ))
767 ;; For non-tail call, we have to save our
768 ;; frame pointer and install the new frame
769 ;; pointer. We can't load stack tns after this
770 ;; point.
772 ;; here which doesn't leave room for the
773 ;; ofp/ret stuff.
775 ;; The variable args are on the stack and
776 ;; become the frame, but there may be <3
777 ;; args and 3 stack slots are assumed
778 ;; allocate on the call. So need to ensure
779 ;; there are at least 3 slots. This hack
780 ;; just adds 3 more.
784 ;; Bias the new-fp for use as an fp
788 ;; Save the fp
793 )))
799 DONE
807 n-word-bytes)
808 other-pointer-lowtag)
810 fun-pointer-lowtag))))
812 (:fixed
814 (:unknown
817 node)))
831 ;;; This is defined separately, since it needs special code that BLT's
832 ;;; the arguments down. All the real work is done in the assembly
833 ;;; routine. We just set things up so that it can find what it needs.
844 ;; Move these into the passing locations if they are not already there.
847 ;; 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 RCX with the number of values returned and
886 ;;; RBX with a pointer to the values, set RSP 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 RBX instead of RBP.
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 ;;; RCX -- number of values to find there.
963 ;;; RSI -- pointer to where to find the values.
979 ;; Check for the single case.
983 ;; Return with one value.
985 ;; Clear the stack until ocfp.
987 ;; clear the multiple-value return flag
989 ;; Out of here.
992 ;; Nope, not the single case. Jump to the assembly routine.
1001 \f
1002 ;;;; XEP hackery
1004 ;;; We don't need to do anything special for regular functions.
1009 ;; Don't bother doing anything.
1010 nil))
1012 ;;; Get the lexical environment from its passing location.
1018 ;; Get result.
1021 ;;; Copy a &MORE arg from the argument area to the end of the current
1022 ;;; frame. FIXED is the number of non-&MORE arguments.
1029 ;; Avoid the copy if there are no more args.
1036 ;; Allocate the space on the stack.
1037 ;; stack = rbp + sp->fp-offset - (max 3 frame-size) - (nargs - fixed)
1046 ;; Now: nargs>=1 && nargs>fixed
1048 ;; Save the original count of args.
1052 ;; We must stop when we run out of stack args, not when we
1053 ;; run out of more args.
1054 ;; Number to copy = nargs-3
1056 ;; Everything of interest in registers.
1059 ;; Number to copy = nargs-fixed
1062 ;; Initialize R8 to be the end of args.
1067 ;; We need to copy from downwards up to avoid overwriting some of
1068 ;; the yet uncopied args. So we need to use R9 as the copy index
1069 ;; and RCX as the loop counter, rather than using RCX for both.
1072 ;; We used to use REP MOVS here, but on modern x86 it performs
1073 ;; much worse than an explicit loop for small blocks.
1074 COPY-LOOP
1081 DO-REGS
1083 ;; Restore RCX
1086 ;; Here: nargs>=1 && nargs>fixed
1088 ;; Now we have to deposit any more args that showed up in
1089 ;; registers.
1092 ;; Store it relative to rbp
1106 ;; Don't deposit any more than there are.
1114 JUST-ALLOC-FRAME
1121 DONE))
1150 ;;; Turn more arg (context, count) into a list.
1170 ;; Check to see whether there are no args, and just return NIL if so.
1176 ;; Set decrement mode (successive args at lower addresses)
1178 ;; Set up the result.
1180 ;; Jump into the middle of the loop, 'cause that's where we want
1181 ;; to start.
1184 ;; Compute a pointer to the next cons.
1186 ;; Store a pointer to this cons in the CDR of the previous cons.
1189 ;; Grab one value and stash it in the car of this cons.
1192 ;; Go back for more.
1195 ;; NIL out the last cons.
1200 ;;; Return the location and size of the &MORE arg glob created by
1201 ;;; COPY-MORE-ARG. SUPPLIED is the total number of arguments supplied
1202 ;;; (originally passed in RCX). FIXED is the number of non-rest
1203 ;;; arguments.
1204 ;;;
1205 ;;; We must duplicate some of the work done by COPY-MORE-ARG, since at
1206 ;;; that time the environment is in a pretty brain-damaged state,
1207 ;;; preventing this info from being returned as values. What we do is
1208 ;;; compute supplied - fixed, and return a pointer that many words
1209 ;;; below the current stack top.
1222 ;; SP at this point points at the last arg pushed.
1223 ;; Point to the first more-arg, not above it.
1230 ;;; Signal wrong argument count error if NARGS isn't equal to COUNT.
1247 ;;; Various other error signallers.
1255 args))
1263 object type)
1265 object layout)
1272 ;;; Single-stepping
1275 ;; We use different ways of representing whether stepping is on on
1276 ;; +SB-THREAD / -SB-THREAD: on +SB-THREAD, we use a slot in the
1277 ;; thread structure. On -SB-THREAD we use the value of a static
1278 ;; symbol. Things are done this way, since reading a thread-local
1279 ;; slot from a symbol would require an extra register on +SB-THREAD,
1280 ;; and reading a slot from a thread structure would require an extra
1281 ;; register on -SB-THREAD. While this isn't critical for x86-64,
1282 ;; it's more serious for x86.
1283 #!+sb-thread
1285 :base thread-base-tn
1287 nil-value)
1288 #!-sb-thread
1294 nil-value))
1303 DONE