-/* Copyright (C) 2010 Free Software Foundation, Inc.
+/* Copyright (C) 2010, 2011, 2012 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
# include <config.h>
#endif
+#include <alloca.h>
+
#include "libguile/_scm.h"
#include "libguile/control.h"
+#include "libguile/objcodes.h"
+#include "libguile/instructions.h"
#include "libguile/vm.h"
\f
-SCM scm_atcontrol (SCM, SCM, SCM);
-SCM_DEFINE (scm_atcontrol, "@control", 3, 0, 0,
- (SCM tag, SCM type, SCM args),
- "Transfer control to the handler of a delimited continuation.")
-#define FUNC_NAME s_scm_atcontrol
-{
- abort ();
- return SCM_UNSPECIFIED;
-}
-#undef FUNC_NAME
-
-SCM scm_atprompt (SCM, SCM, SCM, SCM);
-SCM_DEFINE (scm_atprompt, "@prompt", 4, 0, 0,
- (SCM tag, SCM thunk, SCM handler, SCM pre_unwind_handler),
- "Begin a delimited continuation.")
-#define FUNC_NAME s_scm_atprompt
-{
- abort ();
- return SCM_UNSPECIFIED;
-}
-#undef FUNC_NAME
SCM
-scm_c_make_prompt (SCM vm, SCM k, SCM handler, scm_t_uint8 inline_handler_p,
- scm_t_uint8 escape_only_p)
+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;
- SCM ret;
struct scm_prompt_registers *regs;
tag = scm_tc7_prompt;
- if (inline_handler_p)
- tag |= SCM_F_PROMPT_INLINE;
if (escape_only_p)
- tag |= SCM_F_PROMPT_ESCAPE;
- ret = scm_words (tag, 5);
+ tag |= (SCM_F_PROMPT_ESCAPE<<8);
regs = scm_gc_malloc_pointerless (sizeof (*regs), "prompt registers");
- regs->fp = SCM_VM_DATA (vm)->fp;
- regs->sp = SCM_VM_DATA (vm)->sp;
- regs->ip = SCM_VM_DATA (vm)->ip;
+ 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 */
+SCM
+scm_i_prompt_pop_abort_args_x (SCM vm)
+{
+ size_t i, n;
+ SCM vals = SCM_EOL;
+
+ n = scm_to_size_t (SCM_VM_DATA (vm)->sp[0]);
+ for (i = 0; i < n; i++)
+ vals = scm_cons (SCM_VM_DATA (vm)->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;
+ /* 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
+
+#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
+
+
+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 */
+};
+
+
+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;
- SCM_SET_CELL_OBJECT (ret, 1, k);
- SCM_SET_CELL_WORD (ret, 2, (scm_t_bits)regs);
- SCM_SET_CELL_OBJECT (ret, 3, scm_i_dynwinds ());
- SCM_SET_CELL_OBJECT (ret, 4, handler);
+ 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;
+
+ /* 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,
+ 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;
}
+void
+scm_c_abort (SCM vm, SCM tag, size_t n, SCM *argv, scm_t_int64 cookie)
+{
+ SCM cont, winds, prompt = SCM_BOOL_F;
+ long delta;
+ 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))
+ scm_misc_error ("abort", "Abort to unknown prompt", scm_list_1 (tag));
-\f
+ cont = reify_partial_continuation (vm, prompt, winds, cookie);
-static void
-scm_init_control (void)
+ /* Unwind once more, beyond the prompt. */
+ winds = SCM_CDR (winds), delta++;
+
+ /* Unwind */
+ scm_dowinds (winds, delta);
+
+ /* Unwinding may have changed the current thread's VM, so use the
+ new one. */
+ vm = scm_the_vm ();
+
+ /* 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;
+
+ /* 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)
+ abort ();
+
+ /* Push vals */
+ *(++(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 */
+
+ /* Jump! */
+ SCM_I_LONGJMP (SCM_PROMPT_REGISTERS (prompt)->regs, 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
{
-#ifndef SCM_MAGIC_SNARFER
-#include "libguile/control.x"
-#endif
+ SCM *argv;
+ size_t i;
+ long n;
+
+ SCM_VALIDATE_LIST_COPYLEN (SCM_ARG2, args, n);
+ argv = alloca (sizeof (SCM)*n);
+ 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);
+
+ /* 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...
+ abort! */
+
+ abort ();
+}
+#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_register_control (void)
+scm_init_control (void)
{
- scm_c_register_extension ("libguile", "scm_init_control",
- (scm_t_extension_init_func)scm_init_control,
- NULL);
+#include "libguile/control.x"
}
/*
HCoop / bpt / guile.git / blobdiff