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the dynamic stack is really a stack now, instead of a list
* libguile/dynstack.h: * libguile/dynstack.c: New files, implementing the dynamic stack as a true stack instead of a linked list. This lowers the cost of dynwinds: frames, winders, prompts, with-fluids, and dynamic-wind. For the most part, we allocate these items directly on the stack. * libguile/dynwinds.h: * libguile/dynwinds.c: Adapt all manipulators of the wind stack to use interfaces from dynstack.c. Remove heap-allocated winder and frame object types. (scm_dowinds, scm_i_dowinds): Remove these. The first was exported, but it was not a public interface. * libguile/continuations.c: * libguile/continuations.h (scm_t_contregs): Continuation objects reference scm_t_dynstack* values now. Adapt to the new interfaces. * libguile/control.c: * libguile/control.h: There is no longer a scm_tc7_prompt kind of object that can be allocated on the heap. Instead, the prompt flags, key, and registers are pushed on the dynwind stack. (The registers are still on the heap.) Also, since the vm_cont will reference the dynwinds, make the partial continuation stub take just one extra arg, instead of storing the intwinds separately in the object table. * libguile/fluids.c: * libguile/fluids.h: No more with-fluids objects; instead, the fluids go on the dynstack. The values still have to be on the heap, though. (scm_prepare_fluids, scm_swap_fluids): New internal functions, replacing scm_i_make_with_fluids and scm_i_swap_with_fluids. * libguile/print.c: Remove prompt and with-fluids printers. * libguile/tags.h: Revert prompt and with-fluids tc7 values to what they were before they were allocated. * libguile/vm-i-system.c (partial_cont_call): Just pop the vmcont, the intwinds will not be passed as a second arg. Rewind the dynamic stack from within the VM, so that any rewinder sees valid prompt entries. (call_cc, tail_call_cc): Adapt to pass the dynstack to scm_i_vm_capture_stack. (prompt, wind, unwind, wind_fluids, unwind_fluids): Adapt to the new interfaces. * libguile/vm.h (scm_i_capture_current_stack): Rename from scm_i_vm_capture_continuation. (scm_i_vm_capture_stack): Take a dynstack as an argument. * libguile/vm.c (vm_reinstate_partial_continuation): Don't wind here, as that could result in winders seeing invalid prompts. * libguile/eval.c: * libguile/root.c: * libguile/stacks.c: * libguile/threads.c: * libguile/threads.h: * libguile/throw.c: Adapt other users of dynwinds to use the dynstack.
This commit is contained in:
Andy Wingo
parent
05b4d9106d
commit
9ede013f68
22 changed files with 1079 additions and 534 deletions
206
libguile/dynstack.h
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206
libguile/dynstack.h
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/* classes: h_files */
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#ifndef SCM_DYNSTACK_H
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#define SCM_DYNSTACK_H
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/* Copyright (C) 2012 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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#include "libguile/__scm.h"
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#include "libguile/control.h"
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typedef struct
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{
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scm_t_bits *base;
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scm_t_bits *top;
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scm_t_bits *limit;
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} scm_t_dynstack;
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/* Items on the dynstack are preceded by two-word headers, giving the
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offset of the preceding item (or 0 if there is none) and the type,
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flags, and length of the following dynstack entry, in words. In
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addition, there is a "null header" at the top of the stack,
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indicating the length of the previous item, but with a tag of zero.
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For example, consider an empty dynstack, with a capacity of 6 words:
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+----------+----------+ +
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|prev=0 |tag=0 | |
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+----------+----------+ +
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^base ^top limit^
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Now we evaluate (dynamic-wind enter thunk leave). That will result
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in a dynstack of:
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/ the len=2 words \
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+----------+----------+----------+----------+----------+----------+
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|prev=0 |tag:len=2 |enter |leave |prev=4 |tag=0 |
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+----------+----------+----------+----------+----------+----------+
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^base top,limit^
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The tag is a combination of the type of the dynstack item, some flags
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associated with the item, and the length of the item. See
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SCM_MAKE_DYNSTACK_TAG below for the details.
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This arrangement makes it possible to have variable-length dynstack
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items, and yet be able to traverse them forwards or backwards. */
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#define SCM_DYNSTACK_HEADER_LEN 2
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#define SCM_DYNSTACK_PREV_OFFSET(top) ((top)[-2])
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#define SCM_DYNSTACK_SET_PREV_OFFSET(top, offset) (top)[-2] = (offset)
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#define SCM_DYNSTACK_TAG(top) ((top)[-1])
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#define SCM_DYNSTACK_SET_TAG(top, tag) (top)[-1] = (tag)
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typedef enum {
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SCM_DYNSTACK_TYPE_NONE = 0,
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SCM_DYNSTACK_TYPE_FRAME,
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SCM_DYNSTACK_TYPE_UNWINDER,
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SCM_DYNSTACK_TYPE_REWINDER,
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SCM_DYNSTACK_TYPE_WITH_FLUIDS,
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SCM_DYNSTACK_TYPE_PROMPT,
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SCM_DYNSTACK_TYPE_DYNWIND,
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} scm_t_dynstack_item_type;
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#define SCM_DYNSTACK_TAG_TYPE_MASK 0xf
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#define SCM_DYNSTACK_TAG_FLAGS_MASK 0xf0
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#define SCM_DYNSTACK_TAG_FLAGS_SHIFT 4
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#define SCM_DYNSTACK_TAG_LEN_SHIFT 8
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#define SCM_MAKE_DYNSTACK_TAG(type, flags, len) \
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((type) | (flags) | ((len) << SCM_DYNSTACK_TAG_LEN_SHIFT))
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#define SCM_DYNSTACK_TAG_TYPE(tag) \
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((tag) & SCM_DYNSTACK_TAG_TYPE_MASK)
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#define SCM_DYNSTACK_TAG_FLAGS(tag) \
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((tag) & SCM_DYNSTACK_TAG_FLAGS_MASK)
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#define SCM_DYNSTACK_TAG_LEN(tag) \
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((tag) >> SCM_DYNSTACK_TAG_LEN_SHIFT)
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#define SCM_DYNSTACK_PREV(top) \
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(SCM_DYNSTACK_PREV_OFFSET (top) \
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? ((top) - SCM_DYNSTACK_PREV_OFFSET (top)) : NULL)
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#define SCM_DYNSTACK_NEXT(top) \
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(SCM_DYNSTACK_TAG (top) \
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? ((top) + SCM_DYNSTACK_TAG_LEN (SCM_DYNSTACK_TAG (top)) \
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+ SCM_DYNSTACK_HEADER_LEN) \
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: NULL)
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#define SCM_DYNSTACK_FIRST(dynstack) \
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((dynstack)->base + SCM_DYNSTACK_HEADER_LEN)
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#define SCM_DYNSTACK_CAPACITY(dynstack) \
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((dynstack)->limit - (dynstack)->base)
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#define SCM_DYNSTACK_SPACE(dynstack) \
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((dynstack)->limit - (dynstack)->top)
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#define SCM_DYNSTACK_HEIGHT(dynstack) \
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((dynstack)->top - (dynstack)->base)
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#define SCM_DYNSTACK_HAS_SPACE(dynstack, n) \
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(SCM_DYNSTACK_SPACE (dynstack) >= n + SCM_DYNSTACK_HEADER_LEN)
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typedef enum {
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SCM_F_DYNSTACK_FRAME_REWINDABLE = (1 << SCM_DYNSTACK_TAG_FLAGS_SHIFT)
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} scm_t_dynstack_frame_flags;
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typedef enum {
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SCM_F_DYNSTACK_WINDER_EXPLICIT = (1 << SCM_DYNSTACK_TAG_FLAGS_SHIFT)
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} scm_t_dynstack_winder_flags;
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typedef enum {
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SCM_F_DYNSTACK_PROMPT_ESCAPE_ONLY = (1 << SCM_DYNSTACK_TAG_FLAGS_SHIFT)
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} scm_t_dynstack_prompt_flags;
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typedef void (*scm_t_guard) (void *);
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/* Pushing and popping entries on the dynamic stack. */
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SCM_INTERNAL void scm_dynstack_push_frame (scm_t_dynstack *,
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scm_t_dynstack_frame_flags);
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SCM_INTERNAL void scm_dynstack_push_rewinder (scm_t_dynstack *,
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scm_t_dynstack_winder_flags,
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scm_t_guard, void *);
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SCM_INTERNAL void scm_dynstack_push_unwinder (scm_t_dynstack *,
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scm_t_dynstack_winder_flags,
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scm_t_guard, void *);
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SCM_INTERNAL void scm_dynstack_push_fluids (scm_t_dynstack *,
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size_t,
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SCM *fluids,
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SCM *values,
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SCM dynamic_state);
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SCM_INTERNAL void scm_dynstack_push_prompt (scm_t_dynstack *,
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scm_t_dynstack_prompt_flags,
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SCM key,
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scm_t_prompt_registers *);
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SCM_INTERNAL void scm_dynstack_push_dynwind (scm_t_dynstack *,
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SCM enter, SCM leave);
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SCM_INTERNAL void scm_dynstack_pop (scm_t_dynstack *);
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/* Capturing, winding, and unwinding. */
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SCM_INTERNAL scm_t_dynstack* scm_dynstack_capture_all (scm_t_dynstack *dynstack);
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SCM_INTERNAL scm_t_dynstack* scm_dynstack_capture (scm_t_dynstack *dynstack,
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scm_t_bits *item);
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SCM_INTERNAL void scm_dynstack_wind_1 (scm_t_dynstack *, scm_t_bits *);
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SCM_INTERNAL scm_t_bits scm_dynstack_unwind_1 (scm_t_dynstack *);
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SCM_INTERNAL void scm_dynstack_wind (scm_t_dynstack *, scm_t_bits *);
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SCM_INTERNAL void scm_dynstack_unwind (scm_t_dynstack *, scm_t_bits *);
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SCM_INTERNAL scm_t_bits* scm_dynstack_unwind_fork (scm_t_dynstack *,
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scm_t_dynstack *);
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SCM_INTERNAL void scm_dynstack_unwind_frame (scm_t_dynstack *);
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SCM_INTERNAL void scm_dynstack_unwind_fluids (scm_t_dynstack *dynstack,
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SCM dynamic_state);
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/* Miscellany. */
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SCM_INTERNAL scm_t_bits* scm_dynstack_find_prompt (scm_t_dynstack *, SCM,
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scm_t_prompt_registers **,
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scm_t_dynstack_prompt_flags *);
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SCM_INTERNAL scm_t_prompt_registers*
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scm_dynstack_relocate_prompt (scm_t_dynstack *, scm_t_ptrdiff, scm_t_uint64);
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#endif /* SCM_DYNSTACK_H */
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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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