diff options
Diffstat (limited to 'libguile/control.c')
-rw-r--r-- | libguile/control.c | 273 |
1 files changed, 104 insertions, 169 deletions
diff --git a/libguile/control.c b/libguile/control.c index f8d2d60ae..347d69715 100644 --- a/libguile/control.c +++ b/libguile/control.c @@ -1,4 +1,4 @@ -/* Copyright (C) 2010, 2011, 2012 Free Software Foundation, Inc. +/* Copyright (C) 2010, 2011, 2012, 2013 Free Software Foundation, Inc. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public License @@ -24,227 +24,170 @@ #include "libguile/_scm.h" #include "libguile/control.h" -#include "libguile/objcodes.h" +#include "libguile/programs.h" #include "libguile/instructions.h" #include "libguile/vm.h" +#define PROMPT_ESCAPE_P(p) \ + (SCM_DYNSTACK_TAG_FLAGS (SCM_DYNSTACK_TAG (p)) \ + & SCM_F_DYNSTACK_PROMPT_ESCAPE_ONLY) -SCM -scm_c_make_prompt (SCM k, SCM *fp, SCM *sp, scm_t_uint8 *abort_ip, - scm_t_uint8 escape_only_p, scm_t_int64 vm_cookie, - SCM winds) -{ - scm_t_bits tag; - struct scm_prompt_registers *regs; - - tag = scm_tc7_prompt; - if (escape_only_p) - tag |= (SCM_F_PROMPT_ESCAPE<<8); - - regs = scm_gc_malloc_pointerless (sizeof (*regs), "prompt registers"); - regs->fp = fp; - regs->sp = sp; - regs->ip = abort_ip; - regs->cookie = vm_cookie; + - return scm_double_cell (tag, SCM_UNPACK (k), (scm_t_bits)regs, - SCM_UNPACK (winds)); -} -/* Only to be called if the SCM_PROMPT_SETJMP returns 1 */ +/* Only to be called if the SCM_I_SETJMP returns 1 */ SCM -scm_i_prompt_pop_abort_args_x (SCM vm) +scm_i_prompt_pop_abort_args_x (struct scm_vm *vp) { size_t i, n; SCM vals = SCM_EOL; - n = scm_to_size_t (SCM_VM_DATA (vm)->sp[0]); + n = scm_to_size_t (vp->sp[0]); for (i = 0; i < n; i++) - vals = scm_cons (SCM_VM_DATA (vm)->sp[-(i + 1)], vals); + vals = scm_cons (vp->sp[-(i + 1)], vals); /* The abort did reset the VM's registers, but then these values were pushed on; so we need to pop them ourselves. */ - SCM_VM_DATA (vm)->sp -= n + 1; + vp->sp -= n + 1; /* FIXME NULLSTACK */ return vals; } -#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 +static const scm_t_uint32 compose_continuation_code[] = + { + SCM_PACK_OP_24 (compose_continuation, 0) + }; -#define OBJCODE_TAG SCM_MAKE_OBJCODE_TAG (SCM_OBJCODE_TYPE_STATIC, 0) - -#if defined (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[] -#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) = { \ - { SCM_PACK (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) -#else -#define SCM_STATIC_OBJCODE(sym) \ -static SCM sym; \ -static scm_t_uint8 *sym##_bytecode; \ -SCM_SNARF_INIT(sym##_bytecode = scm_gc_malloc_pointerless (sizeof(sym##_bytecode__unaligned), "partial continuation stub"); \ - memcpy (sym##_bytecode, sym##_bytecode__unaligned, sizeof(sym##_bytecode__unaligned));) \ -SCM_SNARF_INIT(sym = scm_double_cell (OBJCODE_TAG, \ - (scm_t_bits)sym##_bytecode, \ - SCM_UNPACK (SCM_BOOL_F), \ - 0);) \ -static const scm_t_uint8 sym##_bytecode__unaligned[] -#endif +static SCM +make_partial_continuation (SCM vm_cont) +{ + scm_t_bits nfree = 1; + scm_t_bits flags = SCM_F_PROGRAM_IS_PARTIAL_CONTINUATION; + SCM ret; -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_partial_cont_call, /* and go! */ - /* 5 */ scm_op_nop, scm_op_nop, 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, 5, /* 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 */ -}; + ret = scm_words (scm_tc7_program | (nfree << 16) | flags, nfree + 2); + SCM_SET_CELL_WORD_1 (ret, compose_continuation_code); + SCM_PROGRAM_FREE_VARIABLE_SET (ret, 0, vm_cont); + return ret; +} static SCM -reify_partial_continuation (SCM vm, SCM prompt, SCM extwinds, - scm_t_int64 cookie) +reify_partial_continuation (struct scm_vm *vp, + SCM *saved_fp, + SCM *saved_sp, + scm_t_uint32 *saved_ip, + scm_i_jmp_buf *saved_registers, + scm_t_dynstack *dynstack, + scm_i_jmp_buf *current_registers) { - SCM vm_cont, dynwinds, intwinds = SCM_EOL, ret; + SCM vm_cont; 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); - } + SCM *bottom_fp; flags = SCM_F_VM_CONT_PARTIAL; - if (cookie >= 0 && SCM_PROMPT_REGISTERS (prompt)->cookie == cookie) + /* If we are aborting to a prompt that has the same registers as those + of the abort, it means there are no intervening C frames on the + stack, and so the continuation can be relocated elsewhere on the + stack: it is rewindable. */ + if (saved_registers && saved_registers == current_registers) flags |= SCM_F_VM_CONT_REWINDABLE; - /* Since non-escape continuations should begin with a thunk application, the - first bit of the stack should be a frame, with the saved fp equal to the fp - that was current when the prompt was made. */ - if ((SCM*)SCM_UNPACK (SCM_PROMPT_REGISTERS (prompt)->sp[1]) - != SCM_PROMPT_REGISTERS (prompt)->fp) - abort (); - - /* Capture from the top of the thunk application frame up to the end. Set an - MVRA only, as the post-abort code is in an MV context. */ - vm_cont = scm_i_vm_capture_stack (SCM_PROMPT_REGISTERS (prompt)->sp + 4, - SCM_VM_DATA (vm)->fp, - SCM_VM_DATA (vm)->sp, - NULL, - SCM_VM_DATA (vm)->ip, + /* Walk the stack down until we find the first frame after saved_fp. + We will save the stack down to that frame. It used to be that we + could determine the stack bottom in O(1) time, but that's no longer + the case, since the thunk application doesn't occur where the + prompt is saved. */ + for (bottom_fp = vp->fp; + SCM_FRAME_DYNAMIC_LINK (bottom_fp) > saved_fp; + bottom_fp = SCM_FRAME_DYNAMIC_LINK (bottom_fp)); + + if (SCM_FRAME_DYNAMIC_LINK (bottom_fp) != saved_fp) + abort(); + + /* Capture from the top of the thunk application frame up to the end. */ + vm_cont = scm_i_vm_capture_stack (&SCM_FRAME_LOCAL (bottom_fp, 0), + vp->fp, + vp->sp, + vp->ip, + dynstack, flags); - ret = scm_make_program (cont_objcode, - scm_vector (scm_list_2 (vm_cont, intwinds)), - SCM_BOOL_F); - SCM_SET_CELL_WORD_0 (ret, - SCM_CELL_WORD_0 (ret) | SCM_F_PROGRAM_IS_PARTIAL_CONTINUATION); - return ret; + return make_partial_continuation (vm_cont); } void -scm_c_abort (SCM vm, SCM tag, size_t n, SCM *argv, scm_t_int64 cookie) +scm_c_abort (struct scm_vm *vp, SCM tag, size_t n, SCM *argv, + scm_i_jmp_buf *current_registers) { - SCM cont, winds, prompt = SCM_BOOL_F; - long delta; + SCM cont; + scm_t_dynstack *dynstack = &SCM_I_CURRENT_THREAD->dynstack; + scm_t_bits *prompt; + scm_t_dynstack_prompt_flags flags; + scm_t_ptrdiff fp_offset, sp_offset; + SCM *fp, *sp; + scm_t_uint32 *ip; + scm_i_jmp_buf *registers; size_t i; - /* Search the wind list for an appropriate prompt. - "Waiter, please bring us the wind list." */ - for (winds = scm_i_dynwinds (), delta = 0; - scm_is_pair (winds); - winds = SCM_CDR (winds), delta++) - { - SCM elt = SCM_CAR (winds); - if (SCM_PROMPT_P (elt) && scm_is_eq (SCM_PROMPT_TAG (elt), tag)) - { - prompt = elt; - break; - } - } - - /* If we didn't find anything, raise an error. */ - if (scm_is_false (prompt)) + prompt = scm_dynstack_find_prompt (dynstack, tag, + &flags, &fp_offset, &sp_offset, &ip, + ®isters); + + if (!prompt) scm_misc_error ("abort", "Abort to unknown prompt", scm_list_1 (tag)); - cont = reify_partial_continuation (vm, prompt, winds, cookie); + fp = vp->stack_base + fp_offset; + sp = vp->stack_base + sp_offset; - /* Unwind once more, beyond the prompt. */ - winds = SCM_CDR (winds), delta++; + /* Only reify if the continuation referenced in the handler. */ + if (flags & SCM_F_DYNSTACK_PROMPT_ESCAPE_ONLY) + cont = SCM_BOOL_F; + else + { + scm_t_dynstack *captured; - /* Unwind */ - scm_dowinds (winds, delta); + captured = scm_dynstack_capture (dynstack, SCM_DYNSTACK_NEXT (prompt)); + cont = reify_partial_continuation (vp, fp, sp, ip, registers, captured, + current_registers); + } - /* Unwinding may have changed the current thread's VM, so use the - new one. */ - vm = scm_the_vm (); + /* Unwind. */ + scm_dynstack_unwind (dynstack, prompt); /* Restore VM regs */ - SCM_VM_DATA (vm)->fp = SCM_PROMPT_REGISTERS (prompt)->fp; - SCM_VM_DATA (vm)->sp = SCM_PROMPT_REGISTERS (prompt)->sp; - SCM_VM_DATA (vm)->ip = SCM_PROMPT_REGISTERS (prompt)->ip; + vp->fp = fp; + vp->sp = sp; + vp->ip = ip; - /* Since we're jumping down, we should always have enough space */ - if (SCM_VM_DATA (vm)->sp + n + 1 >= SCM_VM_DATA (vm)->stack_limit) + /* Since we're jumping down, we should always have enough space. */ + if (vp->sp + n + 1 >= vp->stack_limit) abort (); /* Push vals */ - *(++(SCM_VM_DATA (vm)->sp)) = cont; + *(++(vp->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 */ + *(++(vp->sp)) = argv[i]; + if (flags & SCM_F_DYNSTACK_PROMPT_PUSH_NARGS) + *(++(vp->sp)) = scm_from_size_t (n+1); /* +1 for continuation */ /* Jump! */ - SCM_I_LONGJMP (SCM_PROMPT_REGISTERS (prompt)->regs, 1); + SCM_I_LONGJMP (*registers, 1); /* Shouldn't get here */ abort (); } -SCM_DEFINE (scm_at_abort, "@abort", 2, 0, 0, (SCM tag, SCM args), - "Abort to the nearest prompt with tag @var{tag}.") -#define FUNC_NAME s_scm_at_abort +SCM_DEFINE (scm_abort_to_prompt_star, "abort-to-prompt*", 2, 0, 0, + (SCM tag, SCM args), + "Abort to the nearest prompt with tag @var{tag}, yielding the\n" + "values in the list, @var{args}.") +#define FUNC_NAME s_scm_abort_to_prompt_star { SCM *argv; size_t i; @@ -255,7 +198,7 @@ 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, -1); + scm_c_abort (scm_the_vm (), tag, n, argv, NULL); /* 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... @@ -266,14 +209,6 @@ SCM_DEFINE (scm_at_abort, "@abort", 2, 0, 0, (SCM tag, SCM args), #undef FUNC_NAME void -scm_i_prompt_print (SCM exp, SCM port, scm_print_state *pstate SCM_UNUSED) -{ - scm_puts ("#<prompt ", port); - scm_intprint (SCM_UNPACK (exp), 16, port); - scm_putc ('>', port); -} - -void scm_init_control (void) { #include "libguile/control.x" |