/
call.lisp
1358 lines (1228 loc) · 47.2 KB
/
call.lisp
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;;;; function call for the x86 VM
;;;; This software is part of the SBCL system. See the README file for
;;;; more information.
;;;;
;;;; This software is derived from the CMU CL system, which was
;;;; written at Carnegie Mellon University and released into the
;;;; public domain. The software is in the public domain and is
;;;; provided with absolutely no warranty. See the COPYING and CREDITS
;;;; files for more information.
(in-package "SB!VM")
;;;; interfaces to IR2 conversion
;;; Return a wired TN describing the N'th full call argument passing
;;; location.
(!def-vm-support-routine standard-arg-location (n)
(declare (type unsigned-byte n))
(if (< n register-arg-count)
(make-wired-tn *backend-t-primitive-type* descriptor-reg-sc-number
(nth n *register-arg-offsets*))
(make-wired-tn *backend-t-primitive-type* control-stack-sc-number n)))
;;; Make a passing location TN for a local call return PC.
;;;
;;; Always wire the return PC location to the stack in its standard
;;; location.
(!def-vm-support-routine make-return-pc-passing-location (standard)
(declare (ignore standard))
(make-wired-tn (primitive-type-or-lose 'system-area-pointer)
sap-stack-sc-number return-pc-save-offset))
;;; This is similar to MAKE-RETURN-PC-PASSING-LOCATION, but makes a
;;; location to pass OLD-FP in.
;;;
;;; This is wired in both the standard and the local-call conventions,
;;; because we want to be able to assume it's always there. Besides,
;;; the x86 doesn't have enough registers to really make it profitable
;;; to pass it in a register.
(!def-vm-support-routine make-old-fp-passing-location (standard)
(declare (ignore standard))
(make-wired-tn *fixnum-primitive-type* control-stack-sc-number
ocfp-save-offset))
;;; Make the TNs used to hold OLD-FP and RETURN-PC within the current
;;; function. We treat these specially so that the debugger can find
;;; them at a known location.
;;;
;;; Without using a save-tn - which does not make much sense if it is
;;; wired to the stack?
(!def-vm-support-routine make-old-fp-save-location (physenv)
(physenv-debug-live-tn (make-wired-tn *fixnum-primitive-type*
control-stack-sc-number
ocfp-save-offset)
physenv))
(!def-vm-support-routine make-return-pc-save-location (physenv)
(physenv-debug-live-tn
(make-wired-tn (primitive-type-or-lose 'system-area-pointer)
sap-stack-sc-number return-pc-save-offset)
physenv))
;;; Make a TN for the standard argument count passing location. We only
;;; need to make the standard location, since a count is never passed when we
;;; are using non-standard conventions.
(!def-vm-support-routine make-arg-count-location ()
(make-wired-tn *fixnum-primitive-type* any-reg-sc-number rcx-offset))
;;; Make a TN to hold the number-stack frame pointer. This is allocated
;;; once per component, and is component-live.
(!def-vm-support-routine make-nfp-tn ()
(make-restricted-tn *fixnum-primitive-type* ignore-me-sc-number))
(!def-vm-support-routine make-stack-pointer-tn ()
(make-normal-tn *fixnum-primitive-type*))
(!def-vm-support-routine make-number-stack-pointer-tn ()
(make-restricted-tn *fixnum-primitive-type* ignore-me-sc-number))
;;; Return a list of TNs that can be used to represent an unknown-values
;;; continuation within a function.
(!def-vm-support-routine make-unknown-values-locations ()
(list (make-stack-pointer-tn)
(make-normal-tn *fixnum-primitive-type*)))
;;; This function is called by the ENTRY-ANALYZE phase, allowing
;;; VM-dependent initialization of the IR2-COMPONENT structure. We
;;; push placeholder entries in the CONSTANTS to leave room for
;;; additional noise in the code object header.
(!def-vm-support-routine select-component-format (component)
(declare (type component component))
;; The 1+ here is because for the x86 the first constant is a
;; pointer to a list of fixups, or NIL if the code object has none.
;; (If I understand correctly, the fixups are needed at GC copy
;; time because the X86 code isn't relocatable.)
;;
;; KLUDGE: It'd be cleaner to have the fixups entry be a named
;; element of the CODE (aka component) primitive object. However,
;; it's currently a large, tricky, error-prone chore to change
;; the layout of any primitive object, so for the foreseeable future
;; we'll just live with this ugliness. -- WHN 2002-01-02
(dotimes (i (1+ code-constants-offset))
(vector-push-extend nil
(ir2-component-constants (component-info component))))
(values))
;;;; frame hackery
;;; This is used for setting up the Old-FP in local call.
(define-vop (current-fp)
(:results (val :scs (any-reg control-stack)))
(:generator 1
(move val rbp-tn)))
;;; We don't have a separate NFP, so we don't need to do anything here.
(define-vop (compute-old-nfp)
(:results (val))
(:ignore val)
(:generator 1
nil))
(define-vop (xep-allocate-frame)
(:info start-lab copy-more-arg-follows)
(:vop-var vop)
(:generator 1
(align n-lowtag-bits)
(trace-table-entry trace-table-fun-prologue)
(emit-label start-lab)
;; Skip space for the function header.
(inst simple-fun-header-word)
(dotimes (i (* n-word-bytes (1- simple-fun-code-offset)))
(inst byte 0))
;; The start of the actual code.
;; Save the return-pc.
(popw rbp-tn (- (1+ return-pc-save-offset)))
;; If copy-more-arg follows it will allocate the correct stack
;; size. The stack is not allocated first here as this may expose
;; args on the stack if they take up more space than the frame!
(unless copy-more-arg-follows
;; The args fit within the frame so just allocate the frame.
(inst lea rsp-tn
(make-ea :qword :base rbp-tn
:disp (- (* n-word-bytes
(max 3 (sb-allocated-size 'stack)))))))
(trace-table-entry trace-table-normal)))
;;; This is emitted directly before either a known-call-local, call-local,
;;; or a multiple-call-local. All it does is allocate stack space for the
;;; callee (who has the same size stack as us).
(define-vop (allocate-frame)
(:results (res :scs (any-reg control-stack))
(nfp))
(:info callee)
(:ignore nfp callee)
(:generator 2
(move res rsp-tn)
(inst sub rsp-tn (* n-word-bytes (sb-allocated-size 'stack)))))
;;; Allocate a partial frame for passing stack arguments in a full
;;; call. NARGS is the number of arguments passed. We allocate at
;;; least 3 slots, because the XEP noise is going to want to use them
;;; before it can extend the stack.
(define-vop (allocate-full-call-frame)
(:info nargs)
(:results (res :scs (any-reg control-stack)))
(:generator 2
(move res rsp-tn)
(inst sub rsp-tn (* (max nargs 3) n-word-bytes))))
;;; Emit code needed at the return-point from an unknown-values call
;;; for a fixed number of values. Values is the head of the TN-REF
;;; list for the locations that the values are to be received into.
;;; Nvals is the number of values that are to be received (should
;;; equal the length of Values).
;;;
;;; MOVE-TEMP is a DESCRIPTOR-REG TN used as a temporary.
;;;
;;; This code exploits the fact that in the unknown-values convention,
;;; a single value return returns at the return PC + 2, whereas a
;;; return of other than one value returns directly at the return PC.
;;;
;;; If 0 or 1 values are expected, then we just emit an instruction to
;;; reset the SP (which will only be executed when other than 1 value
;;; is returned.)
;;;
;;; In the general case we have to do three things:
;;; -- Default unsupplied register values. This need only be done
;;; when a single value is returned, since register values are
;;; defaulted by the called in the non-single case.
;;; -- Default unsupplied stack values. This needs to be done whenever
;;; there are stack values.
;;; -- Reset SP. This must be done whenever other than 1 value is
;;; returned, regardless of the number of values desired.
(defun default-unknown-values (vop values nvals)
(declare (type (or tn-ref null) values)
(type unsigned-byte nvals))
(cond
((<= nvals 1)
(note-this-location vop :single-value-return)
(inst mov rsp-tn rbx-tn))
((<= nvals register-arg-count)
(let ((regs-defaulted (gen-label)))
(note-this-location vop :unknown-return)
(inst jmp-short regs-defaulted)
;; Default the unsupplied registers.
(let* ((2nd-tn-ref (tn-ref-across values))
(2nd-tn (tn-ref-tn 2nd-tn-ref)))
(inst mov 2nd-tn nil-value)
(when (> nvals 2)
(loop
for tn-ref = (tn-ref-across 2nd-tn-ref)
then (tn-ref-across tn-ref)
for count from 2 below register-arg-count
do (inst mov (tn-ref-tn tn-ref) 2nd-tn))))
(inst mov rbx-tn rsp-tn)
(emit-label regs-defaulted)
(inst mov rsp-tn rbx-tn)))
((<= nvals 7)
;; The number of bytes depends on the relative jump instructions.
;; Best case is 31+(n-3)*14, worst case is 35+(n-3)*18. For
;; NVALS=6 that is 73/89 bytes, and for NVALS=7 that is 87/107
;; bytes which is likely better than using the blt below.
(let ((regs-defaulted (gen-label))
(defaulting-done (gen-label))
(default-stack-slots (gen-label)))
(note-this-location vop :unknown-return)
;; Branch off to the MV case.
(inst jmp-short regs-defaulted)
;; Do the single value case.
;; Default the register args
(inst mov rax-tn nil-value)
(do ((i 1 (1+ i))
(val (tn-ref-across values) (tn-ref-across val)))
((= i (min nvals register-arg-count)))
(inst mov (tn-ref-tn val) rax-tn))
;; Fake other registers so it looks like we returned with all the
;; registers filled in.
(move rbx-tn rsp-tn)
(inst push rdx-tn)
(inst jmp default-stack-slots)
(emit-label regs-defaulted)
(inst mov rax-tn nil-value)
(storew rdx-tn rbx-tn -1)
(collect ((defaults))
(do ((i register-arg-count (1+ i))
(val (do ((i 0 (1+ i))
(val values (tn-ref-across val)))
((= i register-arg-count) val))
(tn-ref-across val)))
((null val))
(let ((default-lab (gen-label))
(tn (tn-ref-tn val)))
(defaults (cons default-lab tn))
(inst cmp rcx-tn (fixnumize i))
(inst jmp :be default-lab)
(loadw rdx-tn rbx-tn (- (1+ i)))
(inst mov tn rdx-tn)))
(emit-label defaulting-done)
(loadw rdx-tn rbx-tn -1)
(move rsp-tn rbx-tn)
(let ((defaults (defaults)))
(when defaults
(assemble (*elsewhere*)
(trace-table-entry trace-table-fun-prologue)
(emit-label default-stack-slots)
(dolist (default defaults)
(emit-label (car default))
(inst mov (cdr default) rax-tn))
(inst jmp defaulting-done)
(trace-table-entry trace-table-normal)))))))
(t
(let ((regs-defaulted (gen-label))
(restore-edi (gen-label))
(no-stack-args (gen-label))
(default-stack-vals (gen-label))
(count-okay (gen-label)))
(note-this-location vop :unknown-return)
;; Branch off to the MV case.
(inst jmp-short regs-defaulted)
;; Default the register args, and set up the stack as if we
;; entered the MV return point.
(inst mov rbx-tn rsp-tn)
(inst push rdx-tn)
(inst mov rdi-tn nil-value)
(inst push rdi-tn)
(inst mov rsi-tn rdi-tn)
;; Compute a pointer to where to put the [defaulted] stack values.
(emit-label no-stack-args)
(inst lea rdi-tn
(make-ea :qword :base rbp-tn
:disp (* (- (1+ register-arg-count)) n-word-bytes)))
;; Load RAX with NIL so we can quickly store it, and set up
;; stuff for the loop.
(inst mov rax-tn nil-value)
(inst std)
(inst mov rcx-tn (- nvals register-arg-count))
;; Jump into the default loop.
(inst jmp default-stack-vals)
;; The regs are defaulted. We need to copy any stack arguments,
;; and then default the remaining stack arguments.
(emit-label regs-defaulted)
;; Save EDI.
(storew rdi-tn rbx-tn (- (1+ 1)))
;; Compute the number of stack arguments, and if it's zero or
;; less, don't copy any stack arguments.
(inst sub rcx-tn (fixnumize register-arg-count))
(inst jmp :le no-stack-args)
;; Throw away any unwanted args.
(inst cmp rcx-tn (fixnumize (- nvals register-arg-count)))
(inst jmp :be count-okay)
(inst mov rcx-tn (fixnumize (- nvals register-arg-count)))
(emit-label count-okay)
;; Save the number of stack values.
(inst mov rax-tn rcx-tn)
;; Compute a pointer to where the stack args go.
(inst lea rdi-tn
(make-ea :qword :base rbp-tn
:disp (* (- (1+ register-arg-count)) n-word-bytes)))
;; Save ESI, and compute a pointer to where the args come from.
(storew rsi-tn rbx-tn (- (1+ 2)))
(inst lea rsi-tn
(make-ea :qword :base rbx-tn
:disp (* (- (1+ register-arg-count)) n-word-bytes)))
;; Do the copy.
(inst shr rcx-tn word-shift) ; make word count
(inst std)
(inst rep)
(inst movs :qword)
;; Restore RSI.
(loadw rsi-tn rbx-tn (- (1+ 2)))
;; Now we have to default the remaining args. Find out how many.
(inst sub rax-tn (fixnumize (- nvals register-arg-count)))
(inst neg rax-tn)
;; If none, then just blow out of here.
(inst jmp :le restore-edi)
(inst mov rcx-tn rax-tn)
(inst shr rcx-tn word-shift) ; word count
;; Load RAX with NIL for fast storing.
(inst mov rax-tn nil-value)
;; Do the store.
(emit-label default-stack-vals)
(inst rep)
(inst stos rax-tn)
;; Restore EDI, and reset the stack.
(emit-label restore-edi)
(loadw rdi-tn rbx-tn (- (1+ 1)))
(inst mov rsp-tn rbx-tn))))
(values))
;;;; unknown values receiving
;;; Emit code needed at the return point for an unknown-values call
;;; for an arbitrary number of values.
;;;
;;; We do the single and non-single cases with no shared code: there
;;; doesn't seem to be any potential overlap, and receiving a single
;;; value is more important efficiency-wise.
;;;
;;; When there is a single value, we just push it on the stack,
;;; returning the old SP and 1.
;;;
;;; When there is a variable number of values, we move all of the
;;; argument registers onto the stack, and return ARGS and NARGS.
;;;
;;; ARGS and NARGS are TNs wired to the named locations. We must
;;; explicitly allocate these TNs, since their lifetimes overlap with
;;; the results start and count. (Also, it's nice to be able to target
;;; them.)
(defun receive-unknown-values (args nargs start count)
(declare (type tn args nargs start count))
(let ((variable-values (gen-label))
(done (gen-label)))
(inst jmp-short variable-values)
(cond ((location= start (first *register-arg-tns*))
(inst push (first *register-arg-tns*))
(inst lea start (make-ea :qword :base rsp-tn :disp 8)))
(t (inst mov start rsp-tn)
(inst push (first *register-arg-tns*))))
(inst mov count (fixnumize 1))
(inst jmp done)
(emit-label variable-values)
;; dtc: this writes the registers onto the stack even if they are
;; not needed, only the number specified in rcx are used and have
;; stack allocated to them. No harm is done.
(loop
for arg in *register-arg-tns*
for i downfrom -1
do (storew arg args i))
(move start args)
(move count nargs)
(emit-label done))
(values))
;;; VOP that can be inherited by unknown values receivers. The main thing this
;;; handles is allocation of the result temporaries.
(define-vop (unknown-values-receiver)
(:temporary (:sc descriptor-reg :offset rbx-offset
:from :eval :to (:result 0))
values-start)
(:temporary (:sc any-reg :offset rcx-offset
:from :eval :to (:result 1))
nvals)
(:results (start :scs (any-reg control-stack))
(count :scs (any-reg control-stack))))
;;;; local call with unknown values convention return
;;; Non-TR local call for a fixed number of values passed according to
;;; the unknown values convention.
;;;
;;; FP is the frame pointer in install before doing the call.
;;;
;;; NFP would be the number-stack frame pointer if we had a separate
;;; number stack.
;;;
;;; Args are the argument passing locations, which are specified only
;;; to terminate their lifetimes in the caller.
;;;
;;; VALUES are the return value locations (wired to the standard
;;; passing locations). NVALS is the number of values received.
;;;
;;; Save is the save info, which we can ignore since saving has been
;;; done.
;;;
;;; TARGET is a continuation pointing to the start of the called
;;; function.
(define-vop (call-local)
(:args (fp)
(nfp)
(args :more t))
(:results (values :more t))
(:save-p t)
(:move-args :local-call)
(:info arg-locs callee target nvals)
(:vop-var vop)
(:ignore nfp arg-locs args #+nil callee)
(:generator 5
(trace-table-entry trace-table-call-site)
(move rbp-tn fp)
(let ((ret-tn (callee-return-pc-tn callee)))
#+nil
(format t "*call-local ~S; tn-kind ~S; tn-save-tn ~S; its tn-kind ~S~%"
ret-tn (sb!c::tn-kind ret-tn) (sb!c::tn-save-tn ret-tn)
(sb!c::tn-kind (sb!c::tn-save-tn ret-tn)))
;; Is the return-pc on the stack or in a register?
(sc-case ret-tn
((sap-stack)
#+nil (format t "*call-local: ret-tn on stack; offset=~S~%"
(tn-offset ret-tn))
(storew (make-fixup nil :code-object return)
rbp-tn (- (1+ (tn-offset ret-tn)))))
((sap-reg)
(inst lea ret-tn (make-fixup nil :code-object return)))))
(note-this-location vop :call-site)
(inst jmp target)
RETURN
(default-unknown-values vop values nvals)
(trace-table-entry trace-table-normal)))
;;; Non-TR local call for a variable number of return values passed according
;;; to the unknown values convention. The results are the start of the values
;;; glob and the number of values received.
(define-vop (multiple-call-local unknown-values-receiver)
(:args (fp)
(nfp)
(args :more t))
(:save-p t)
(:move-args :local-call)
(:info save callee target)
(:ignore args save nfp #+nil callee)
(:vop-var vop)
(:generator 20
(trace-table-entry trace-table-call-site)
(move rbp-tn fp)
(let ((ret-tn (callee-return-pc-tn callee)))
#+nil
(format t "*multiple-call-local ~S; tn-kind ~S; tn-save-tn ~S; its tn-kind ~S~%"
ret-tn (sb!c::tn-kind ret-tn) (sb!c::tn-save-tn ret-tn)
(sb!c::tn-kind (sb!c::tn-save-tn ret-tn)))
;; Is the return-pc on the stack or in a register?
(sc-case ret-tn
((sap-stack)
#+nil (format t "*multiple-call-local: ret-tn on stack; offset=~S~%"
(tn-offset ret-tn))
;; Stack
(storew (make-fixup nil :code-object return)
rbp-tn (- (1+ (tn-offset ret-tn)))))
((sap-reg)
;; Register
(inst lea ret-tn (make-fixup nil :code-object return)))))
(note-this-location vop :call-site)
(inst jmp target)
RETURN
(note-this-location vop :unknown-return)
(receive-unknown-values values-start nvals start count)
(trace-table-entry trace-table-normal)))
;;;; local call with known values return
;;; Non-TR local call with known return locations. Known-value return
;;; works just like argument passing in local call.
;;;
;;; Note: we can't use normal load-tn allocation for the fixed args,
;;; since all registers may be tied up by the more operand. Instead,
;;; we use MAYBE-LOAD-STACK-TN.
(define-vop (known-call-local)
(:args (fp)
(nfp)
(args :more t))
(:results (res :more t))
(:move-args :local-call)
(:save-p t)
(:info save callee target)
(:ignore args res save nfp #+nil callee)
(:vop-var vop)
(:generator 5
(trace-table-entry trace-table-call-site)
(move rbp-tn fp)
(let ((ret-tn (callee-return-pc-tn callee)))
#+nil
(format t "*known-call-local ~S; tn-kind ~S; tn-save-tn ~S; its tn-kind ~S~%"
ret-tn (sb!c::tn-kind ret-tn) (sb!c::tn-save-tn ret-tn)
(sb!c::tn-kind (sb!c::tn-save-tn ret-tn)))
;; Is the return-pc on the stack or in a register?
(sc-case ret-tn
((sap-stack)
#+nil (format t "*known-call-local: ret-tn on stack; offset=~S~%"
(tn-offset ret-tn))
;; Stack
(storew (make-fixup nil :code-object return)
rbp-tn (- (1+ (tn-offset ret-tn)))))
((sap-reg)
;; Register
(inst lea ret-tn (make-fixup nil :code-object return)))))
(note-this-location vop :call-site)
(inst jmp target)
RETURN
(note-this-location vop :known-return)
(trace-table-entry trace-table-normal)))
;;; Return from known values call. We receive the return locations as
;;; arguments to terminate their lifetimes in the returning function. We
;;; restore FP and CSP and jump to the Return-PC.
;;;
;;; We can assume we know exactly where old-fp and return-pc are because
;;; make-old-fp-save-location and make-return-pc-save-location always
;;; return the same place.
#+nil
(define-vop (known-return)
(:args (old-fp)
(return-pc :scs (any-reg immediate-stack) :target rpc)
(vals :more t))
(:move-args :known-return)
(:info val-locs)
(:temporary (:sc unsigned-reg :from (:argument 1)) rpc)
(:ignore val-locs vals)
(:vop-var vop)
(:generator 6
(trace-table-entry trace-table-fun-epilogue)
;; Save the return-pc in a register 'cause the frame-pointer is
;; going away. Note this not in the usual stack location so we
;; can't use RET
(move rpc return-pc)
;; Restore the stack.
(move rsp-tn rbp-tn)
;; Restore the old fp. We know OLD-FP is going to be in its stack
;; save slot, which is a different frame that than this one,
;; so we don't have to worry about having just cleared
;; most of the stack.
(move rbp-tn old-fp)
(inst jmp rpc)
(trace-table-entry trace-table-normal)))
;;; From Douglas Crosher
;;; Return from known values call. We receive the return locations as
;;; arguments to terminate their lifetimes in the returning function. We
;;; restore FP and CSP and jump to the Return-PC.
;;;
;;; The old-fp may be either in a register or on the stack in its
;;; standard save locations - slot 0.
;;;
;;; The return-pc may be in a register or on the stack in any slot.
(define-vop (known-return)
(:args (old-fp)
(return-pc)
(vals :more t))
(:move-args :known-return)
(:info val-locs)
(:ignore val-locs vals)
(:vop-var vop)
(:generator 6
(trace-table-entry trace-table-fun-epilogue)
;; return-pc may be either in a register or on the stack.
(sc-case return-pc
((sap-reg)
(sc-case old-fp
((control-stack)
(cond ((zerop (tn-offset old-fp))
;; Zot all of the stack except for the old-fp.
(inst lea rsp-tn (make-ea :qword :base rbp-tn
:disp (- (* (1+ ocfp-save-offset)
n-word-bytes))))
;; Restore the old fp from its save location on the stack,
;; and zot the stack.
(inst pop rbp-tn))
(t
(cerror "Continue anyway"
"VOP return-local doesn't work if old-fp (in slot ~
~S) is not in slot 0"
(tn-offset old-fp)))))
((any-reg descriptor-reg)
;; Zot all the stack.
(move rsp-tn rbp-tn)
;; Restore the old-fp.
(move rbp-tn old-fp)))
;; Return; return-pc is in a register.
(inst jmp return-pc))
((sap-stack)
(inst lea rsp-tn
(make-ea :qword :base rbp-tn
:disp (- (* (1+ (tn-offset return-pc)) n-word-bytes))))
(move rbp-tn old-fp)
(inst ret (* (tn-offset return-pc) n-word-bytes))))
(trace-table-entry trace-table-normal)))
;;;; full call
;;;
;;; There is something of a cross-product effect with full calls.
;;; Different versions are used depending on whether we know the
;;; number of arguments or the name of the called function, and
;;; whether we want fixed values, unknown values, or a tail call.
;;;
;;; In full call, the arguments are passed creating a partial frame on
;;; the stack top and storing stack arguments into that frame. On
;;; entry to the callee, this partial frame is pointed to by FP.
;;; This macro helps in the definition of full call VOPs by avoiding
;;; code replication in defining the cross-product VOPs.
;;;
;;; NAME is the name of the VOP to define.
;;;
;;; NAMED is true if the first argument is an fdefinition object whose
;;; definition is to be called.
;;;
;;; RETURN is either :FIXED, :UNKNOWN or :TAIL:
;;; -- If :FIXED, then the call is for a fixed number of values, returned in
;;; the standard passing locations (passed as result operands).
;;; -- If :UNKNOWN, then the result values are pushed on the stack, and the
;;; result values are specified by the Start and Count as in the
;;; unknown-values continuation representation.
;;; -- If :TAIL, then do a tail-recursive call. No values are returned.
;;; The Old-Fp and Return-PC are passed as the second and third arguments.
;;;
;;; In non-tail calls, the pointer to the stack arguments is passed as
;;; the last fixed argument. If Variable is false, then the passing
;;; locations are passed as a more arg. Variable is true if there are
;;; a variable number of arguments passed on the stack. Variable
;;; cannot be specified with :TAIL return. TR variable argument call
;;; is implemented separately.
;;;
;;; In tail call with fixed arguments, the passing locations are
;;; passed as a more arg, but there is no new-FP, since the arguments
;;; have been set up in the current frame.
(macrolet ((define-full-call (name named return variable)
(aver (not (and variable (eq return :tail))))
`(define-vop (,name
,@(when (eq return :unknown)
'(unknown-values-receiver)))
(:args
,@(unless (eq return :tail)
'((new-fp :scs (any-reg) :to (:argument 1))))
(fun :scs (descriptor-reg control-stack)
:target rax :to (:argument 0))
,@(when (eq return :tail)
'((old-fp)
(return-pc)))
,@(unless variable '((args :more t :scs (descriptor-reg)))))
,@(when (eq return :fixed)
'((:results (values :more t))))
(:save-p ,(if (eq return :tail) :compute-only t))
,@(unless (or (eq return :tail) variable)
'((:move-args :full-call)))
(:vop-var vop)
(:info
,@(unless (or variable (eq return :tail)) '(arg-locs))
,@(unless variable '(nargs))
,@(when (eq return :fixed) '(nvals)))
(:ignore
,@(unless (or variable (eq return :tail)) '(arg-locs))
,@(unless variable '(args)))
;; We pass either the fdefn object (for named call) or
;; the actual function object (for unnamed call) in
;; RAX. With named call, closure-tramp will replace it
;; with the real function and invoke the real function
;; for closures. Non-closures do not need this value,
;; so don't care what shows up in it.
(:temporary
(:sc descriptor-reg
:offset rax-offset
:from (:argument 0)
:to :eval)
rax)
;; We pass the number of arguments in RCX.
(:temporary (:sc unsigned-reg :offset rcx-offset :to :eval) rcx)
;; With variable call, we have to load the
;; register-args out of the (new) stack frame before
;; doing the call. Therefore, we have to tell the
;; lifetime stuff that we need to use them.
,@(when variable
(mapcar (lambda (name offset)
`(:temporary (:sc descriptor-reg
:offset ,offset
:from (:argument 0)
:to :eval)
,name))
*register-arg-names* *register-arg-offsets*))
,@(when (eq return :tail)
'((:temporary (:sc unsigned-reg
:from (:argument 1)
:to (:argument 2))
old-fp-tmp)))
(:generator ,(+ (if named 5 0)
(if variable 19 1)
(if (eq return :tail) 0 10)
15
(if (eq return :unknown) 25 0))
(trace-table-entry trace-table-call-site)
;; This has to be done before the frame pointer is
;; changed! RAX stores the 'lexical environment' needed
;; for closures.
(move rax fun)
,@(if variable
;; For variable call, compute the number of
;; arguments and move some of the arguments to
;; registers.
(collect ((noise))
;; Compute the number of arguments.
(noise '(inst mov rcx new-fp))
(noise '(inst sub rcx rsp-tn))
;; Move the necessary args to registers,
;; this moves them all even if they are
;; not all needed.
(loop
for name in *register-arg-names*
for index downfrom -1
do (noise `(loadw ,name new-fp ,index)))
(noise))
'((if (zerop nargs)
(inst xor rcx rcx)
(inst mov rcx (fixnumize nargs)))))
,@(cond ((eq return :tail)
'(;; Python has figured out what frame we should
;; return to so might as well use that clue.
;; This seems really important to the
;; implementation of things like
;; (without-interrupts ...)
;;
;; dtc; Could be doing a tail call from a
;; known-local-call etc in which the old-fp
;; or ret-pc are in regs or in non-standard
;; places. If the passing location were
;; wired to the stack in standard locations
;; then these moves will be un-necessary;
;; this is probably best for the x86.
(sc-case old-fp
((control-stack)
(unless (= ocfp-save-offset
(tn-offset old-fp))
;; FIXME: FORMAT T for stale
;; diagnostic output (several of
;; them around here), ick
(format t "** tail-call old-fp not S0~%")
(move old-fp-tmp old-fp)
(storew old-fp-tmp
rbp-tn
(- (1+ ocfp-save-offset)))))
((any-reg descriptor-reg)
(format t "** tail-call old-fp in reg not S0~%")
(storew old-fp
rbp-tn
(- (1+ ocfp-save-offset)))))
;; For tail call, we have to push the
;; return-pc so that it looks like we CALLed
;; drspite the fact that we are going to JMP.
(inst push return-pc)
))
(t
;; For non-tail call, we have to save our
;; frame pointer and install the new frame
;; pointer. We can't load stack tns after this
;; point.
`(;; Python doesn't seem to allocate a frame
;; here which doesn't leave room for the
;; ofp/ret stuff.
;; The variable args are on the stack and
;; become the frame, but there may be <3
;; args and 3 stack slots are assumed
;; allocate on the call. So need to ensure
;; there are at least 3 slots. This hack
;; just adds 3 more.
,(if variable
'(inst sub rsp-tn (fixnumize 3)))
;; Save the fp
(storew rbp-tn new-fp (- (1+ ocfp-save-offset)))
(move rbp-tn new-fp) ; NB - now on new stack frame.
)))
(note-this-location vop :call-site)
(inst ,(if (eq return :tail) 'jmp 'call)
(make-ea :qword :base rax
:disp ,(if named
'(- (* fdefn-raw-addr-slot
n-word-bytes)
other-pointer-lowtag)
'(- (* closure-fun-slot n-word-bytes)
fun-pointer-lowtag))))
,@(ecase return
(:fixed
'((default-unknown-values vop values nvals)))
(:unknown
'((note-this-location vop :unknown-return)
(receive-unknown-values values-start nvals start count)))
(:tail))
(trace-table-entry trace-table-normal)))))
(define-full-call call nil :fixed nil)
(define-full-call call-named t :fixed nil)
(define-full-call multiple-call nil :unknown nil)
(define-full-call multiple-call-named t :unknown nil)
(define-full-call tail-call nil :tail nil)
(define-full-call tail-call-named t :tail nil)
(define-full-call call-variable nil :fixed t)
(define-full-call multiple-call-variable nil :unknown t))
;;; This is defined separately, since it needs special code that BLT's
;;; the arguments down. All the real work is done in the assembly
;;; routine. We just set things up so that it can find what it needs.
(define-vop (tail-call-variable)
(:args (args :scs (any-reg control-stack) :target rsi)
(function :scs (descriptor-reg control-stack) :target rax)
(old-fp)
(ret-addr))
(:temporary (:sc unsigned-reg :offset rsi-offset :from (:argument 0)) rsi)
(:temporary (:sc unsigned-reg :offset rax-offset :from (:argument 1)) rax)
; (:ignore ret-addr old-fp)
(:generator 75
;; Move these into the passing locations if they are not already there.
(move rsi args)
(move rax function)
;; The following assumes that the return-pc and old-fp are on the
;; stack in their standard save locations - Check this.
(unless (and (sc-is old-fp control-stack)
(= (tn-offset old-fp) ocfp-save-offset))
(error "tail-call-variable: ocfp not on stack in standard save location?"))
(unless (and (sc-is ret-addr sap-stack)
(= (tn-offset ret-addr) return-pc-save-offset))
(error "tail-call-variable: ret-addr not on stack in standard save location?"))
;; And jump to the assembly routine.
(inst jmp (make-fixup 'tail-call-variable :assembly-routine))))
;;;; unknown values return
;;; Return a single-value using the Unknown-Values convention. Specifically,
;;; we jump to clear the stack and jump to return-pc+3.
;;;
;;; We require old-fp to be in a register, because we want to reset RSP before
;;; restoring RBP. If old-fp were still on the stack, it could get clobbered
;;; by a signal.
;;;
;;; pfw--get wired-tn conflicts sometimes if register sc specd for args
;;; having problems targeting args to regs -- using temps instead.
(define-vop (return-single)
(:args (old-fp)
(return-pc)
(value))
(:temporary (:sc unsigned-reg) ofp)
(:temporary (:sc unsigned-reg) ret)
(:ignore value)
(:generator 6
(trace-table-entry trace-table-fun-epilogue)
(move ret return-pc)
;; Clear the control stack
(move ofp old-fp)
;; Adjust the return address for the single value return.
(inst add ret 3)
;; Restore the frame pointer.
(move rsp-tn rbp-tn)
(move rbp-tn ofp)
;; Out of here.
(inst jmp ret)))
;;; Do unknown-values return of a fixed (other than 1) number of
;;; values. The VALUES are required to be set up in the standard
;;; passing locations. NVALS is the number of values returned.
;;;
;;; Basically, we just load RCX with the number of values returned and
;;; RBX with a pointer to the values, set RSP to point to the end of
;;; the values, and jump directly to return-pc.
(define-vop (return)
(:args (old-fp)
(return-pc :to (:eval 1))
(values :more t))
(:ignore values)
(:info nvals)
;; In the case of other than one value, we need these registers to
;; tell the caller where they are and how many there are.
(:temporary (:sc unsigned-reg :offset rbx-offset) rbx)
(:temporary (:sc unsigned-reg :offset rcx-offset) rcx)
;; We need to stretch the lifetime of return-pc past the argument
;; registers so that we can default the argument registers without
;; trashing return-pc.
(:temporary (:sc unsigned-reg :offset (first *register-arg-offsets*)
:from :eval) a0)
(:temporary (:sc unsigned-reg :offset (second *register-arg-offsets*)
:from :eval) a1)
(:temporary (:sc unsigned-reg :offset (third *register-arg-offsets*)
:from :eval) a2)
(:generator 6
(trace-table-entry trace-table-fun-epilogue)
;; Establish the values pointer and values count.
(move rbx rbp-tn)
(if (zerop nvals)
(inst xor rcx rcx) ; smaller
(inst mov rcx (fixnumize nvals)))
;; Restore the frame pointer.
(move rbp-tn old-fp)
;; Clear as much of the stack as possible, but not past the return
;; address.
(inst lea rsp-tn (make-ea :qword :base rbx
:disp (- (* (max nvals 2) n-word-bytes))))
;; Pre-default any argument register that need it.
(when (< nvals register-arg-count)
(let* ((arg-tns (nthcdr nvals (list a0 a1 a2)))
(first (first arg-tns)))
(inst mov first nil-value)
(dolist (tn (cdr arg-tns))
(inst mov tn first))))
;; And away we go. Except that return-pc is still on the
;; stack and we've changed the stack pointer. So we have to
;; tell it to index off of RBX instead of RBP.
(cond ((zerop nvals)
;; Return popping the return address and the OCFP.