diff options
author | Andy Wingo <wingo@pobox.com> | 2010-02-22 23:00:19 +0100 |
---|---|---|
committer | Andy Wingo <wingo@pobox.com> | 2010-02-22 23:00:19 +0100 |
commit | cee1d22c3c10b1892c82a5758ef69cd6fc9aba31 (patch) | |
tree | 03628430d2426ab2148587d19ee386f82a9f09aa | |
parent | 76e3816281cf6c406ef6f01907ce29401c8ff455 (diff) | |
download | guile-cee1d22c3c10b1892c82a5758ef69cd6fc9aba31.tar.gz |
actually capture partial continuations
* libguile/control.c (cont_objcode): Along with a bunch of boilerplate
that certainly needs to go in some central place, define this
continuation-calling trampoline.
(reify_partial_continuation): New function, returns a procedure that
when called will reinstate a partial continuation.
(scm_c_abort): Take an extra arg, the cookie. Actually reify a
continuation.
(scm_at_abort): Adapt to scm_c_abort change.
* libguile/control.h: Declare scm_c_abort change.
* libguile/vm-i-system.c (partial_cont_call): New instruction.
(call/cc, tail-call/cc): Adapt to scm_i_vm_capture_stack change.
(abort): Pass vm_cookie to abort.
* libguile/vm.h (SCM_F_VM_CONT_PARTIAL, SCM_F_VM_CONT_REWINDABLE): New
flags.
(struct scm_vm_cont): Add flags field.
(SCM_VM_CONT_PARTIAL_P, SCM_VM_CONT_REWINDABLE_P): New predicates.
* libguile/vm.c (scm_i_vm_capture_stack): Rename from
vm_capture_continuation, and make internal instead of static. Take a
flags argument.
(scm_i_vm_capture_continuation): Adapt to scm_i_vm_capture_stack
change.
(vm_abort): Plumb cookie to scm_c_abort.
(vm_reinstate_partial_continuation): New stub.
-rw-r--r-- | libguile/control.c | 117 | ||||
-rw-r--r-- | libguile/control.h | 3 | ||||
-rw-r--r-- | libguile/vm-i-system.c | 26 | ||||
-rw-r--r-- | libguile/vm.c | 22 | ||||
-rw-r--r-- | libguile/vm.h | 9 |
5 files changed, 158 insertions, 19 deletions
diff --git a/libguile/control.c b/libguile/control.c index 371ec2d20..25c95047b 100644 --- a/libguile/control.c +++ b/libguile/control.c @@ -22,6 +22,8 @@ #include "libguile/_scm.h" #include "libguile/control.h" +#include "libguile/objcodes.h" +#include "libguile/instructions.h" #include "libguile/vm.h" @@ -52,10 +54,115 @@ scm_c_make_prompt (SCM vm, SCM k, scm_t_uint8 escape_only_p, return ret; } +#ifdef WORDS_BIGENDIAN +#define OBJCODE_HEADER(main,meta) 0, 0, 0, main, 0, 0, 0, meta+8 +#define META_HEADER(meta) 0, 0, 0, meta, 0, 0, 0, 0 +#else +#define OBJCODE_HEADER(main,meta) main, 0, 0, 0, meta+8, 0, 0, 0 +#define META_HEADER(meta) meta, 0, 0, 0, 0, 0, 0, 0 +#endif + +#define ROUND_UP(len,align) (((len-1)|(align-1))+1) +#define ALIGN_PTR(type,p,align) (type*)(ROUND_UP (((scm_t_bits)p), align)) + +#ifdef SCM_ALIGNED +#define SCM_DECLARE_STATIC_ALIGNED_ARRAY(type, sym)\ +static const type sym[] +#define SCM_STATIC_ALIGNED_ARRAY(alignment, type, sym)\ +static SCM_ALIGNED (alignment) const type sym[] +#else +#define SCM_DECLARE_STATIC_ALIGNED_ARRAY(type, sym)\ +static type *sym +#define SCM_STATIC_ALIGNED_ARRAY(alignment, type, sym) \ +SCM_SNARF_INIT(sym = scm_malloc (sizeof(sym##__unaligned) + alignment - 1); \ + sym = ALIGN_PTR (type, sym, alignment); \ + memcpy (sym, sym##__unaligned, sizeof(sym##__unaligned));) \ +static type *sym = NULL; \ +static const type sym##__unaligned[] +#endif + +#define STATIC_OBJCODE_TAG \ + SCM_PACK (scm_tc7_objcode | (SCM_F_OBJCODE_IS_STATIC << 8)) + +#define SCM_STATIC_OBJCODE(sym) \ + SCM_DECLARE_STATIC_ALIGNED_ARRAY (scm_t_uint8, sym##__bytecode); \ + SCM_STATIC_ALIGNED_ARRAY (8, scm_t_cell, sym##__cells) = { \ + { STATIC_OBJCODE_TAG, SCM_PACK (sym##__bytecode) }, \ + { SCM_BOOL_F, SCM_PACK (0) } \ + }; \ + static const SCM sym = SCM_PACK (sym##__cells); \ + SCM_STATIC_ALIGNED_ARRAY (8, scm_t_uint8, sym##__bytecode) + + +SCM_STATIC_OBJCODE (cont_objcode) = { + /* Like in continuations.c, but with partial-cont-call. */ + OBJCODE_HEADER (8, 19), + /* leave args on the stack */ + /* 0 */ scm_op_object_ref, 0, /* push scm_vm_cont object */ + /* 2 */ scm_op_object_ref, 1, /* push internal winds */ + /* 4 */ scm_op_object_ref, 2, /* push external winds */ + /* 6 */ scm_op_partial_cont_call, /* and go! */ + /* 7 */ scm_op_nop, /* pad to 8 bytes */ + /* 8 */ + + /* We could put some meta-info to say that this proc is a continuation. Not sure + how to do that, though. */ + META_HEADER (19), + /* 0 */ scm_op_make_eol, /* bindings */ + /* 1 */ scm_op_make_eol, /* sources */ + /* 2 */ scm_op_make_int8, 0, scm_op_make_int8, 7, /* arity: from ip 0 to ip 7 */ + /* 6 */ scm_op_make_int8_0, /* the arity is 0 required args */ + /* 7 */ scm_op_make_int8_0, /* 0 optionals */ + /* 8 */ scm_op_make_true, /* and a rest arg */ + /* 9 */ scm_op_list, 0, 5, /* make a list of those 5 vals */ + /* 12 */ scm_op_list, 0, 1, /* and the arities will be a list of that one list */ + /* 15 */ scm_op_list, 0, 3, /* pack bindings, sources, and arities into list */ + /* 18 */ scm_op_return /* and return */ + /* 19 */ +}; + + +static SCM +reify_partial_continuation (SCM vm, SCM prompt, SCM extwinds, + scm_t_int64 cookie) +{ + SCM vm_cont, dynwinds, intwinds = SCM_EOL, ret; + scm_t_uint32 flags; + + /* No need to reify if the continuation is never referenced in the handler. */ + if (SCM_PROMPT_ESCAPE_P (prompt)) + return SCM_BOOL_F; + + dynwinds = scm_i_dynwinds (); + while (!scm_is_eq (dynwinds, extwinds)) + { + intwinds = scm_cons (scm_car (dynwinds), intwinds); + dynwinds = scm_cdr (dynwinds); + } + + flags = SCM_F_VM_CONT_PARTIAL; + if (cookie >= 0 && SCM_PROMPT_REGISTERS (prompt)->cookie == cookie) + flags |= SCM_F_VM_CONT_REWINDABLE; + + /* NULL RA and MVRA, as those get set when the cont is reinstated */ + vm_cont = scm_i_vm_capture_stack (SCM_PROMPT_REGISTERS (prompt)->sp, + SCM_VM_DATA (vm)->fp, + SCM_VM_DATA (vm)->sp, + NULL, NULL, + flags); + + ret = scm_make_program (cont_objcode, + scm_vector (scm_list_3 (vm_cont, intwinds, extwinds)), + SCM_BOOL_F); + SCM_SET_CELL_WORD_0 (ret, + SCM_CELL_WORD_0 (ret) | SCM_F_PROGRAM_IS_CONTINUATION); + return ret; +} + SCM -scm_c_abort (SCM vm, SCM tag, size_t n, SCM *argv) +scm_c_abort (SCM vm, SCM tag, size_t n, SCM *argv, scm_t_int64 cookie) { - SCM winds, prompt = SCM_BOOL_F; + SCM cont, winds, prompt = SCM_BOOL_F; long delta; size_t i; @@ -83,6 +190,8 @@ scm_c_abort (SCM vm, SCM tag, size_t n, SCM *argv) abort (); } + cont = reify_partial_continuation (vm, prompt, winds, cookie); + /* Unwind once more, beyond the prompt. */ winds = SCM_CDR (winds), delta++; @@ -99,7 +208,7 @@ scm_c_abort (SCM vm, SCM tag, size_t n, SCM *argv) abort (); /* Push vals */ - *(++(SCM_VM_DATA (vm)->sp)) = SCM_BOOL_F; /* the continuation */ + *(++(SCM_VM_DATA (vm)->sp)) = cont; for (i = 0; i < n; i++) *(++(SCM_VM_DATA (vm)->sp)) = argv[i]; *(++(SCM_VM_DATA (vm)->sp)) = scm_from_size_t (n+1); /* +1 for continuation */ @@ -123,7 +232,7 @@ SCM_DEFINE (scm_at_abort, "@abort", 2, 0, 0, (SCM tag, SCM args), for (i = 0; i < n; i++, args = scm_cdr (args)) argv[i] = scm_car (args); - scm_c_abort (scm_the_vm (), tag, n, argv); + scm_c_abort (scm_the_vm (), tag, n, argv, -1); /* Oh, what, you're still here? The abort must have been reinstated. Actually, that's quite impossible, given that we're already in C-land here, so... diff --git a/libguile/control.h b/libguile/control.h index 6144a38c9..160728d8f 100644 --- a/libguile/control.h +++ b/libguile/control.h @@ -44,7 +44,8 @@ struct scm_prompt_registers SCM_INTERNAL SCM scm_c_make_prompt (SCM vm, SCM k, scm_t_uint8 escape_only_p, scm_t_int64 cookie); -SCM_INTERNAL SCM scm_c_abort (SCM vm, SCM tag, size_t n, SCM *argv) SCM_NORETURN; +SCM_INTERNAL SCM scm_c_abort (SCM vm, SCM tag, size_t n, SCM *argv, + scm_t_int64 cookie) SCM_NORETURN; SCM_INTERNAL SCM scm_at_abort (SCM tag, SCM args) SCM_NORETURN; diff --git a/libguile/vm-i-system.c b/libguile/vm-i-system.c index faae6ab3e..09293bef8 100644 --- a/libguile/vm-i-system.c +++ b/libguile/vm-i-system.c @@ -993,6 +993,17 @@ VM_DEFINE_INSTRUCTION (89, continuation_call, "continuation-call", 0, -1, 0) abort (); } +VM_DEFINE_INSTRUCTION (94, partial_cont_call, "partial-cont-call", 0, -1, 0) +{ + SCM vmcont, intwinds, extwinds; + POP (extwinds); + POP (intwinds); + POP (vmcont); + + vm_reinstate_partial_continuation (vm, vmcont, intwinds, extwinds); + NEXT; +} + VM_DEFINE_INSTRUCTION (59, tail_call_nargs, "tail-call/nargs", 0, 0, 1) { SCM x; @@ -1099,7 +1110,7 @@ VM_DEFINE_INSTRUCTION (64, call_cc, "call/cc", 0, 1, 1) SCM proc, vm_cont, cont; POP (proc); SYNC_ALL (); - vm_cont = vm_capture_continuation (vp->stack_base, fp, sp, ip, NULL); + vm_cont = scm_i_vm_capture_stack (vp->stack_base, fp, sp, ip, NULL, 0); cont = scm_i_make_continuation (&first, vm, vm_cont); if (first) { @@ -1131,11 +1142,12 @@ VM_DEFINE_INSTRUCTION (65, tail_call_cc, "tail-call/cc", 0, 1, 1) SYNC_ALL (); /* In contrast to call/cc, tail-call/cc captures the continuation without the stack frame. */ - vm_cont = vm_capture_continuation (vp->stack_base, - SCM_FRAME_DYNAMIC_LINK (fp), - SCM_FRAME_LOWER_ADDRESS (fp) - 1, - SCM_FRAME_RETURN_ADDRESS (fp), - SCM_FRAME_MV_RETURN_ADDRESS (fp)); + vm_cont = scm_i_vm_capture_stack (vp->stack_base, + SCM_FRAME_DYNAMIC_LINK (fp), + SCM_FRAME_LOWER_ADDRESS (fp) - 1, + SCM_FRAME_RETURN_ADDRESS (fp), + SCM_FRAME_MV_RETURN_ADDRESS (fp), + 0); cont = scm_i_make_continuation (&first, vm, vm_cont); if (first) { @@ -1511,7 +1523,7 @@ VM_DEFINE_INSTRUCTION (86, abort, "abort", 1, -1, -1) SYNC_REGISTER (); if (sp - n - 2 <= SCM_FRAME_UPPER_ADDRESS (fp)) goto vm_error_stack_underflow; - vm_abort (vm, n); + vm_abort (vm, n, vm_cookie); /* vm_abort should not return */ abort (); } diff --git a/libguile/vm.c b/libguile/vm.c index 831200fdf..572a7100a 100644 --- a/libguile/vm.c +++ b/libguile/vm.c @@ -91,9 +91,9 @@ scm_i_vm_cont_print (SCM x, SCM port, scm_print_state *pstate) continuation root is inside VM code, and call/cc was invoked within that same call to vm_run; but that's currently not implemented. */ -static SCM -vm_capture_continuation (SCM *stack_base, - SCM *fp, SCM *sp, scm_t_uint8 *ra, scm_t_uint8 *mvra) +SCM +scm_i_vm_capture_stack (SCM *stack_base, SCM *fp, SCM *sp, scm_t_uint8 *ra, + scm_t_uint8 *mvra, scm_t_uint32 flags) { struct scm_vm_cont *p; @@ -116,6 +116,7 @@ vm_capture_continuation (SCM *stack_base, p->fp = fp; memcpy (p->stack_base, stack_base, (sp + 1 - stack_base) * sizeof (SCM)); p->reloc = p->stack_base - stack_base; + p->flags = flags; return scm_cell (scm_tc7_vm_cont, (scm_t_bits)p); } @@ -178,7 +179,7 @@ SCM scm_i_vm_capture_continuation (SCM vm) { struct scm_vm *vp = SCM_VM_DATA (vm); - return vm_capture_continuation (vp->stack_base, vp->fp, vp->sp, vp->ip, NULL); + return scm_i_vm_capture_stack (vp->stack_base, vp->fp, vp->sp, vp->ip, NULL, 0); } static void @@ -201,9 +202,9 @@ vm_dispatch_hook (SCM vm, int hook_num) vp->trace_level++; } -static void vm_abort (SCM vm, size_t n) SCM_NORETURN; +static void vm_abort (SCM vm, size_t n, scm_t_int64 cookie) SCM_NORETURN; static void -vm_abort (SCM vm, size_t n) +vm_abort (SCM vm, size_t n, scm_t_int64 vm_cookie) { size_t i; ssize_t tail_len; @@ -224,7 +225,14 @@ vm_abort (SCM vm, size_t n) /* NULLSTACK (n + 1) */ SCM_VM_DATA (vm)->sp -= n + 1; - scm_c_abort (vm, tag, n + tail_len, argv); + scm_c_abort (vm, tag, n + tail_len, argv, vm_cookie); +} + +static void +vm_reinstate_partial_continuation (SCM vm, SCM vm_cont, SCM intwinds, + SCM extwinds) +{ + abort (); } diff --git a/libguile/vm.h b/libguile/vm.h index 6d76f12e8..48e0bb627 100644 --- a/libguile/vm.h +++ b/libguile/vm.h @@ -87,6 +87,9 @@ SCM_API SCM scm_set_vm_option_x (SCM vm, SCM key, SCM val); SCM_API SCM scm_vm_trace_level (SCM vm); SCM_API SCM scm_set_vm_trace_level_x (SCM vm, SCM level); +#define SCM_F_VM_CONT_PARTIAL 0x1 +#define SCM_F_VM_CONT_REWINDABLE 0x2 + struct scm_vm_cont { SCM *sp; SCM *fp; @@ -94,16 +97,22 @@ struct scm_vm_cont { scm_t_ptrdiff stack_size; SCM *stack_base; scm_t_ptrdiff reloc; + scm_t_uint32 flags; }; #define SCM_VM_CONT_P(OBJ) (SCM_NIMP (OBJ) && SCM_TYP7 (OBJ) == scm_tc7_vm_cont) #define SCM_VM_CONT_DATA(CONT) ((struct scm_vm_cont *) SCM_CELL_WORD_1 (CONT)) +#define SCM_VM_CONT_PARTIAL_P(CONT) (SCM_VM_CONT_DATA (CONT) & SCM_F_VM_CONT_PARTIAL) +#define SCM_VM_CONT_REWINDABLE_P(CONT) (SCM_VM_CONT_DATA (CONT) & SCM_F_VM_CONT_REWINDABLE) SCM_API SCM scm_load_compiled_with_vm (SCM file); SCM_INTERNAL void scm_i_vm_print (SCM x, SCM port, scm_print_state *pstate); SCM_INTERNAL SCM scm_i_vm_capture_continuation (SCM vm); +SCM_INTERNAL SCM scm_i_vm_capture_stack (SCM *stack_base, SCM *fp, SCM *sp, + scm_t_uint8 *ra, scm_t_uint8 *mvra, + scm_t_uint32 flags); SCM_INTERNAL void scm_i_vm_cont_print (SCM x, SCM port, scm_print_state *pstate); SCM_INTERNAL void scm_bootstrap_vm (void); |