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2b14df4bc7
* libguile/control.c (scm_at_abort): Fix to ensure that we store the return of scm_ilength in a signed integer, even if later we copy it to an unsigned. See http://article.gmane.org/gmane.lisp.guile.devel/12685.
287 lines
9.1 KiB
C
287 lines
9.1 KiB
C
/* Copyright (C) 2010, 2011 Free Software Foundation, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public License
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* as published by the Free Software Foundation; either version 3 of
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* the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301 USA
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*/
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#if HAVE_CONFIG_H
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# include <config.h>
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#endif
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#include <alloca.h>
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#include "libguile/_scm.h"
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#include "libguile/control.h"
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#include "libguile/objcodes.h"
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#include "libguile/instructions.h"
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#include "libguile/vm.h"
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SCM
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scm_c_make_prompt (SCM k, SCM *fp, SCM *sp, scm_t_uint8 *abort_ip,
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scm_t_uint8 escape_only_p, scm_t_int64 vm_cookie,
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SCM winds)
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{
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scm_t_bits tag;
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struct scm_prompt_registers *regs;
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tag = scm_tc7_prompt;
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if (escape_only_p)
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tag |= (SCM_F_PROMPT_ESCAPE<<8);
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regs = scm_gc_malloc_pointerless (sizeof (*regs), "prompt registers");
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regs->fp = fp;
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regs->sp = sp;
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regs->ip = abort_ip;
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regs->cookie = vm_cookie;
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return scm_double_cell (tag, SCM_UNPACK (k), (scm_t_bits)regs,
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SCM_UNPACK (winds));
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}
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/* Only to be called if the SCM_PROMPT_SETJMP returns 1 */
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SCM
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scm_i_prompt_pop_abort_args_x (SCM vm)
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{
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size_t i, n;
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SCM vals = SCM_EOL;
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n = scm_to_size_t (SCM_VM_DATA (vm)->sp[0]);
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for (i = 0; i < n; i++)
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vals = scm_cons (SCM_VM_DATA (vm)->sp[-(i + 1)], vals);
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/* The abort did reset the VM's registers, but then these values
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were pushed on; so we need to pop them ourselves. */
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SCM_VM_DATA (vm)->sp -= n + 1;
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/* FIXME NULLSTACK */
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return vals;
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}
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#ifdef WORDS_BIGENDIAN
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#define OBJCODE_HEADER(main,meta) 0, 0, 0, main, 0, 0, 0, meta+8
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#define META_HEADER(meta) 0, 0, 0, meta, 0, 0, 0, 0
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#else
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#define OBJCODE_HEADER(main,meta) main, 0, 0, 0, meta+8, 0, 0, 0
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#define META_HEADER(meta) meta, 0, 0, 0, 0, 0, 0, 0
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#endif
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#define ALIGN_PTR(type,p,align) (type*)(ROUND_UP (((scm_t_bits)p), align))
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#ifdef SCM_ALIGNED
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#define SCM_DECLARE_STATIC_ALIGNED_ARRAY(type, sym) \
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static const type sym[]
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#define SCM_STATIC_ALIGNED_ARRAY(alignment, type, sym) \
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static SCM_ALIGNED (alignment) const type sym[]
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#else
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#define SCM_DECLARE_STATIC_ALIGNED_ARRAY(type, sym) \
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static type *sym
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#define SCM_STATIC_ALIGNED_ARRAY(alignment, type, sym) \
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SCM_SNARF_INIT(sym = scm_malloc_pointerless (sizeof(sym##__unaligned); \
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memcpy (sym, sym##__unaligned, sizeof(sym##__unaligned));) \
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static type *sym = NULL; \
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static const type sym##__unaligned[]
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#endif
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#define STATIC_OBJCODE_TAG \
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SCM_PACK (SCM_MAKE_OBJCODE_TAG (SCM_OBJCODE_TYPE_STATIC, 0))
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#define SCM_STATIC_OBJCODE(sym) \
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SCM_DECLARE_STATIC_ALIGNED_ARRAY (scm_t_uint8, sym##__bytecode); \
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SCM_STATIC_ALIGNED_ARRAY (8, scm_t_cell, sym##__cells) = { \
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{ STATIC_OBJCODE_TAG, SCM_PACK (sym##__bytecode) }, \
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{ SCM_BOOL_F, SCM_PACK (0) } \
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}; \
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static const SCM sym = SCM_PACK (sym##__cells); \
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SCM_STATIC_ALIGNED_ARRAY (8, scm_t_uint8, sym##__bytecode)
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SCM_STATIC_OBJCODE (cont_objcode) = {
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/* Like in continuations.c, but with partial-cont-call. */
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OBJCODE_HEADER (8, 19),
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/* leave args on the stack */
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/* 0 */ scm_op_object_ref, 0, /* push scm_vm_cont object */
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/* 2 */ scm_op_object_ref, 1, /* push internal winds */
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/* 4 */ scm_op_partial_cont_call, /* and go! */
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/* 5 */ scm_op_nop, scm_op_nop, scm_op_nop, /* pad to 8 bytes */
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/* 8 */
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/* We could put some meta-info to say that this proc is a continuation. Not sure
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how to do that, though. */
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META_HEADER (19),
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/* 0 */ scm_op_make_eol, /* bindings */
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/* 1 */ scm_op_make_eol, /* sources */
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/* 2 */ scm_op_make_int8, 0, scm_op_make_int8, 5, /* arity: from ip 0 to ip 7 */
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/* 6 */ scm_op_make_int8_0, /* the arity is 0 required args */
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/* 7 */ scm_op_make_int8_0, /* 0 optionals */
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/* 8 */ scm_op_make_true, /* and a rest arg */
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/* 9 */ scm_op_list, 0, 5, /* make a list of those 5 vals */
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/* 12 */ scm_op_list, 0, 1, /* and the arities will be a list of that one list */
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/* 15 */ scm_op_list, 0, 3, /* pack bindings, sources, and arities into list */
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/* 18 */ scm_op_return /* and return */
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/* 19 */
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};
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static SCM
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reify_partial_continuation (SCM vm, SCM prompt, SCM extwinds,
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scm_t_int64 cookie)
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{
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SCM vm_cont, dynwinds, intwinds = SCM_EOL, ret;
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scm_t_uint32 flags;
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/* No need to reify if the continuation is never referenced in the handler. */
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if (SCM_PROMPT_ESCAPE_P (prompt))
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return SCM_BOOL_F;
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dynwinds = scm_i_dynwinds ();
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while (!scm_is_eq (dynwinds, extwinds))
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{
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intwinds = scm_cons (scm_car (dynwinds), intwinds);
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dynwinds = scm_cdr (dynwinds);
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}
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flags = SCM_F_VM_CONT_PARTIAL;
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if (cookie >= 0 && SCM_PROMPT_REGISTERS (prompt)->cookie == cookie)
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flags |= SCM_F_VM_CONT_REWINDABLE;
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/* Since non-escape continuations should begin with a thunk application, the
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first bit of the stack should be a frame, with the saved fp equal to the fp
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that was current when the prompt was made. */
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if ((SCM*)SCM_UNPACK (SCM_PROMPT_REGISTERS (prompt)->sp[1])
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!= SCM_PROMPT_REGISTERS (prompt)->fp)
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abort ();
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/* Capture from the top of the thunk application frame up to the end. Set an
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MVRA only, as the post-abort code is in an MV context. */
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vm_cont = scm_i_vm_capture_stack (SCM_PROMPT_REGISTERS (prompt)->sp + 4,
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SCM_VM_DATA (vm)->fp,
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SCM_VM_DATA (vm)->sp,
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NULL,
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SCM_VM_DATA (vm)->ip,
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flags);
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ret = scm_make_program (cont_objcode,
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scm_vector (scm_list_2 (vm_cont, intwinds)),
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SCM_BOOL_F);
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SCM_SET_CELL_WORD_0 (ret,
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SCM_CELL_WORD_0 (ret) | SCM_F_PROGRAM_IS_PARTIAL_CONTINUATION);
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return ret;
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}
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void
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scm_c_abort (SCM vm, SCM tag, size_t n, SCM *argv, scm_t_int64 cookie)
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{
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SCM cont, winds, prompt = SCM_BOOL_F;
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long delta;
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size_t i;
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/* Search the wind list for an appropriate prompt.
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"Waiter, please bring us the wind list." */
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for (winds = scm_i_dynwinds (), delta = 0;
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scm_is_pair (winds);
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winds = SCM_CDR (winds), delta++)
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{
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SCM elt = SCM_CAR (winds);
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if (SCM_PROMPT_P (elt) && scm_is_eq (SCM_PROMPT_TAG (elt), tag))
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{
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prompt = elt;
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break;
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}
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}
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/* If we didn't find anything, raise an error. */
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if (scm_is_false (prompt))
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scm_misc_error ("abort", "Abort to unknown prompt", scm_list_1 (tag));
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cont = reify_partial_continuation (vm, prompt, winds, cookie);
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/* Unwind once more, beyond the prompt. */
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winds = SCM_CDR (winds), delta++;
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/* Unwind */
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scm_dowinds (winds, delta);
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/* Unwinding may have changed the current thread's VM, so use the
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new one. */
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vm = scm_the_vm ();
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/* Restore VM regs */
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SCM_VM_DATA (vm)->fp = SCM_PROMPT_REGISTERS (prompt)->fp;
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SCM_VM_DATA (vm)->sp = SCM_PROMPT_REGISTERS (prompt)->sp;
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SCM_VM_DATA (vm)->ip = SCM_PROMPT_REGISTERS (prompt)->ip;
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/* Since we're jumping down, we should always have enough space */
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if (SCM_VM_DATA (vm)->sp + n + 1 >= SCM_VM_DATA (vm)->stack_limit)
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abort ();
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/* Push vals */
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*(++(SCM_VM_DATA (vm)->sp)) = cont;
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for (i = 0; i < n; i++)
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*(++(SCM_VM_DATA (vm)->sp)) = argv[i];
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*(++(SCM_VM_DATA (vm)->sp)) = scm_from_size_t (n+1); /* +1 for continuation */
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/* Jump! */
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SCM_I_LONGJMP (SCM_PROMPT_REGISTERS (prompt)->regs, 1);
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/* Shouldn't get here */
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abort ();
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}
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SCM_DEFINE (scm_at_abort, "@abort", 2, 0, 0, (SCM tag, SCM args),
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"Abort to the nearest prompt with tag @var{tag}.")
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#define FUNC_NAME s_scm_at_abort
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{
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SCM *argv;
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size_t i;
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long n;
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SCM_VALIDATE_LIST_COPYLEN (SCM_ARG2, args, n);
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argv = alloca (sizeof (SCM)*n);
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for (i = 0; i < n; i++, args = scm_cdr (args))
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argv[i] = scm_car (args);
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scm_c_abort (scm_the_vm (), tag, n, argv, -1);
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/* Oh, what, you're still here? The abort must have been reinstated. Actually,
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that's quite impossible, given that we're already in C-land here, so...
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abort! */
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abort ();
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}
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#undef FUNC_NAME
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void
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scm_i_prompt_print (SCM exp, SCM port, scm_print_state *pstate SCM_UNUSED)
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{
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scm_puts ("#<prompt ", port);
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scm_intprint (SCM_UNPACK (exp), 16, port);
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scm_putc ('>', port);
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}
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void
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scm_init_control (void)
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{
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#include "libguile/control.x"
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}
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/*
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Local Variables:
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c-file-style: "gnu"
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End:
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*/
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