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guile/libguile/dynstack.h
Andy Wingo 0007507340 VM stack grows downward 
Adapt VM stack to grow downward.  This will make native compilation look
more like the VM code, as we will be able to use native CALL
instructions, taking proper advantage of the return address buffer.

* libguile/continuations.c (scm_i_continuation_to_frame): Record offsets
  from stack top.

* libguile/control.c (scm_i_prompt_pop_abort_args_x): Adapt for reversed
  order of arguments, and instead of relying on the abort to push on the
  number of arguments, make the caller save the stack depth, which
  allows us to compute the number of arguments ourselves.
  (reify_partial_continuation, scm_c_abort): Adapt to reversed stack
  order.

* libguile/dynstack.c (scm_dynstack_wind_prompt): Since we wind the
  stack in a downward direction, subtract the reloc instead of adding
  it.

* libguile/dynstack.h (SCM_F_DYNSTACK_PROMPT_ESCAPE_ONLY): Remove flag;
  instead rely on prompt-establishing code to save the stack depth.

* libguile/eval.c (eval): Remove extraneous "volatile" declarations for
  variables that are not re-set between the setjmp and any longjmp.
  Adapt to save stack depth before instating the prompt.

* libguile/foreign.c (scm_i_foreign_call): Adapt to receive arguments in
  reverse order.

* libguile/frames.c (frame_stack_top, scm_i_frame_stack_top): Adapt to
  compute stack top instead of stack bottom.
  (scm_c_frame_closure): Adapt to stack growth change.
  (scm_frame_num_locals, scm_frame_local_ref, scm_frame_set_x): Use
  union data type to access stack.
  (RELOC): Reformat.
  (scm_c_frame_previous): Adapt to stack growth change.

* libguile/frames.h: Adapt stack diagram to indicate that the stack
  grows up.
  (union scm_vm_stack_element): New data type used to access items on
  the stack.
  (SCM_FRAME_PREVIOUS_SP)
  (SCM_FRAME_RETURN_ADDRESS, SCM_FRAME_SET_RETURN_ADDRESS)
  (SCM_FRAME_DYNAMIC_LINK, SCM_FRAME_SET_DYNAMIC_LINK)
  (SCM_FRAME_LOCAL, SCM_FRAME_NUM_LOCALS): Adapt to stack representation
  change.
  (SCM_FRAME_SLOT): New helper.
  (SCM_VM_FRAME_FP, SCM_VM_FRAME_SP): Adapt to stack growth change.

* libguile/stacks.c (scm_make_stack): Record offsets from top of stack.

* libguile/throw.c (catch): Adapt to scm_i_prompt_pop_abort_args_x
  change.

* libguile/vm-engine.c (ALLOC_FRAME, RESET_FRAME):
  (FRAME_LOCALS_COUNT_FROM): Adapt to stack growth change.
  (LOCAL_ADDRESS): Use SCM_FRAME_SLOT to get the address as the proper
  data type.
  (RETURN_ONE_VALUE, RETURN_VALUE_LIST): Adapt to stack growth change.
  (apply): Shuffling up the SMOB apply args can cause the stack to
  expand, so use ALLOC_FRAME instead of RESET_FRAME.
  (vm_engine): Adapt for stack growth change.

* libguile/vm.c (vm_increase_sp, vm_push_sp, vm_restore_sp): Adapt to
  stack representation change.
  (scm_i_vm_cont_to_frame): Adapt to take offsets from the top.
  (scm_i_vm_capture_stack): Adapt to capture from the top.
  (vm_return_to_continuation_inner): Adapt for data type changes.
  (vm_return_to_continuation): Likewise, and instead of looping, just
  splat the saved arguments on with memcpy.
  (vm_dispatch_hook): Adapt to receive arguments in the reverse order.
  Adapt callers.
  (vm_abort): There is never a tail argument.  Adapt to stack
  representation change.
  (vm_reinstate_partial_continuation)
  (vm_reinstate_partial_continuation_inner): Adapt to stack growth
  change.
  (allocate_stack, free_stack): Adapt to data type change.
  (expand_stack): Don't try to mremap(), as you can't grow a mapping
  from the bottom.  Without knowing that there's a free mapping space
  right below the old stack, which there usually isn't on Linux, we have
  to copy.  We can't use MAP_GROWSDOWN because Linux is buggy.
  (make_vm): Adapt to stack representation changes.
  (return_unused_stack_to_os): Round down instead of up, as the stack
  grows down.
  (scm_i_vm_mark_stack): Adapt to walk up the stack.
  (scm_i_vm_free_stack): Adapt to scm_vm changes.
  (vm_expand_stack_inner, reset_stack_limit, vm_expand_stack): Adapt to
  the stack growing down.
  (scm_call_n): Adapt to the stack growing down.  Don't allow argv to
  point into the stack.

* libguile/vm.h (struct scm_vm, struct scm_vm_cont): Adapt to hold the
  stack top and bottom.
2015-10-21 11:49:20 +02:00

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/* classes: h_files */
#ifndef SCM_DYNSTACK_H
#define SCM_DYNSTACK_H
/* Copyright (C) 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
* as published by the Free Software Foundation; either version 3 of
* the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301 USA
*/
#include "libguile/__scm.h"
typedef struct
{
scm_t_bits *base;
scm_t_bits *top;
scm_t_bits *limit;
} scm_t_dynstack;
/* Items on the dynstack are preceded by two-word headers, giving the
offset of the preceding item (or 0 if there is none) and the type,
flags, and length of the following dynstack entry, in words. In
addition, there is a "null header" at the top of the stack,
indicating the length of the previous item, but with a tag of zero.
For example, consider an empty dynstack, with a capacity of 6 words:
+----------+----------+ +
|prev=0 |tag=0 | |
+----------+----------+ +
^base ^top limit^
Now we evaluate (dynamic-wind enter thunk leave). That will result
in a dynstack of:
/ the len=2 words \
+----------+----------+----------+----------+----------+----------+
|prev=0 |tag:len=2 |enter |leave |prev=4 |tag=0 |
+----------+----------+----------+----------+----------+----------+
^base top,limit^
The tag is a combination of the type of the dynstack item, some flags
associated with the item, and the length of the item. See
SCM_MAKE_DYNSTACK_TAG below for the details.
This arrangement makes it possible to have variable-length dynstack
items, and yet be able to traverse them forwards or backwards. */
#define SCM_DYNSTACK_HEADER_LEN 2
#define SCM_DYNSTACK_PREV_OFFSET(top) ((top)[-2])
#define SCM_DYNSTACK_SET_PREV_OFFSET(top, offset) (top)[-2] = (offset)
#define SCM_DYNSTACK_TAG(top) ((top)[-1])
#define SCM_DYNSTACK_SET_TAG(top, tag) (top)[-1] = (tag)
typedef enum {
SCM_DYNSTACK_TYPE_NONE = 0,
SCM_DYNSTACK_TYPE_FRAME,
SCM_DYNSTACK_TYPE_UNWINDER,
SCM_DYNSTACK_TYPE_REWINDER,
SCM_DYNSTACK_TYPE_WITH_FLUID,
SCM_DYNSTACK_TYPE_PROMPT,
SCM_DYNSTACK_TYPE_DYNWIND,
} scm_t_dynstack_item_type;
#define SCM_DYNSTACK_TAG_TYPE_MASK 0xf
#define SCM_DYNSTACK_TAG_FLAGS_MASK 0xf0
#define SCM_DYNSTACK_TAG_FLAGS_SHIFT 4
#define SCM_DYNSTACK_TAG_LEN_SHIFT 8
#define SCM_MAKE_DYNSTACK_TAG(type, flags, len) \
((type) | (flags) | ((len) << SCM_DYNSTACK_TAG_LEN_SHIFT))
#define SCM_DYNSTACK_TAG_TYPE(tag) \
((tag) & SCM_DYNSTACK_TAG_TYPE_MASK)
#define SCM_DYNSTACK_TAG_FLAGS(tag) \
((tag) & SCM_DYNSTACK_TAG_FLAGS_MASK)
#define SCM_DYNSTACK_TAG_LEN(tag) \
((tag) >> SCM_DYNSTACK_TAG_LEN_SHIFT)
#define SCM_DYNSTACK_PREV(top) \
(SCM_DYNSTACK_PREV_OFFSET (top) \
? ((top) - SCM_DYNSTACK_PREV_OFFSET (top)) : NULL)
#define SCM_DYNSTACK_NEXT(top) \
(SCM_DYNSTACK_TAG (top) \
? ((top) + SCM_DYNSTACK_TAG_LEN (SCM_DYNSTACK_TAG (top)) \
+ SCM_DYNSTACK_HEADER_LEN) \
: NULL)
#define SCM_DYNSTACK_FIRST(dynstack) \
((dynstack)->base + SCM_DYNSTACK_HEADER_LEN)
#define SCM_DYNSTACK_CAPACITY(dynstack) \
((dynstack)->limit - (dynstack)->base)
#define SCM_DYNSTACK_SPACE(dynstack) \
((dynstack)->limit - (dynstack)->top)
#define SCM_DYNSTACK_HEIGHT(dynstack) \
((dynstack)->top - (dynstack)->base)
#define SCM_DYNSTACK_HAS_SPACE(dynstack, n) \
(SCM_DYNSTACK_SPACE (dynstack) >= n + SCM_DYNSTACK_HEADER_LEN)
typedef enum {
SCM_F_DYNSTACK_FRAME_REWINDABLE = (1 << SCM_DYNSTACK_TAG_FLAGS_SHIFT)
} scm_t_dynstack_frame_flags;
typedef enum {
SCM_F_DYNSTACK_WINDER_EXPLICIT = (1 << SCM_DYNSTACK_TAG_FLAGS_SHIFT)
} scm_t_dynstack_winder_flags;
typedef enum {
SCM_F_DYNSTACK_PROMPT_ESCAPE_ONLY = (1 << SCM_DYNSTACK_TAG_FLAGS_SHIFT)
} scm_t_dynstack_prompt_flags;
typedef void (*scm_t_guard) (void *);
/* Pushing and popping entries on the dynamic stack. */
SCM_INTERNAL void scm_dynstack_push_frame (scm_t_dynstack *,
scm_t_dynstack_frame_flags);
SCM_INTERNAL void scm_dynstack_push_rewinder (scm_t_dynstack *,
scm_t_dynstack_winder_flags,
scm_t_guard, void *);
SCM_INTERNAL void scm_dynstack_push_unwinder (scm_t_dynstack *,
scm_t_dynstack_winder_flags,
scm_t_guard, void *);
SCM_INTERNAL void scm_dynstack_push_fluid (scm_t_dynstack *,
SCM fluid, SCM value,
SCM dynamic_state);
SCM_INTERNAL void scm_dynstack_push_prompt (scm_t_dynstack *,
scm_t_dynstack_prompt_flags,
SCM key,
scm_t_ptrdiff fp_offset,
scm_t_ptrdiff sp_offset,
scm_t_uint32 *ip,
scm_i_jmp_buf *registers);
SCM_INTERNAL void scm_dynstack_push_dynwind (scm_t_dynstack *,
SCM enter, SCM leave);
SCM_INTERNAL void scm_dynstack_pop (scm_t_dynstack *);
/* Capturing, winding, and unwinding. */
SCM_INTERNAL scm_t_dynstack* scm_dynstack_capture_all (scm_t_dynstack *dynstack);
SCM_INTERNAL scm_t_dynstack* scm_dynstack_capture (scm_t_dynstack *dynstack,
scm_t_bits *item);
SCM_INTERNAL void scm_dynstack_wind_1 (scm_t_dynstack *, scm_t_bits *);
SCM_INTERNAL scm_t_bits scm_dynstack_unwind_1 (scm_t_dynstack *);
SCM_INTERNAL void scm_dynstack_wind (scm_t_dynstack *, scm_t_bits *);
SCM_INTERNAL void scm_dynstack_unwind (scm_t_dynstack *, scm_t_bits *);
/* Miscellany. */
SCM_INTERNAL scm_t_bits* scm_dynstack_unwind_fork (scm_t_dynstack *,
scm_t_dynstack *);
SCM_INTERNAL void scm_dynstack_unwind_frame (scm_t_dynstack *);
SCM_INTERNAL void scm_dynstack_unwind_fluid (scm_t_dynstack *dynstack,
SCM dynamic_state);
SCM_INTERNAL scm_t_bits* scm_dynstack_find_prompt (scm_t_dynstack *, SCM,
scm_t_dynstack_prompt_flags *,
scm_t_ptrdiff *,
scm_t_ptrdiff *,
scm_t_uint32 **,
scm_i_jmp_buf **);
SCM_INTERNAL void scm_dynstack_wind_prompt (scm_t_dynstack *, scm_t_bits *,
scm_t_ptrdiff, scm_i_jmp_buf *);
#endif /* SCM_DYNSTACK_H */
/*
Local Variables:
c-file-style: "gnu"
End:
*/
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