-/* Copyright (C) 2001, 2009, 2010, 2011, 2012, 2013 Free Software Foundation, Inc.
+/* Copyright (C) 2001, 2009, 2010, 2011, 2012, 2013, 2014, 2015 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
* 02110-1301 USA
*/
+/* For mremap(2) on GNU/Linux systems. */
+#define _GNU_SOURCE
+
#if HAVE_CONFIG_H
# include <config.h>
#endif
#include <alignof.h>
#include <string.h>
#include <stdint.h>
+#include <unistd.h>
+
+#ifdef HAVE_SYS_MMAN_H
+#include <sys/mman.h>
+#endif
#include "libguile/bdw-gc.h"
#include <gc/gc_mark.h>
#include "_scm.h"
#include "control.h"
#include "frames.h"
+#include "gc-inline.h"
#include "instructions.h"
#include "loader.h"
#include "programs.h"
+#include "simpos.h"
#include "vm.h"
#include "vm-builtins.h"
-#include "private-gc.h" /* scm_getenv_int */
-
static int vm_default_engine = SCM_VM_REGULAR_ENGINE;
/* Unfortunately we can't snarf these: snarfed things are only loaded up from
static SCM sym_regular;
static SCM sym_debug;
+/* The page size. */
+static size_t page_size;
+
/* The VM has a number of internal assertions that shouldn't normally be
necessary, but might be if you think you found a bug in the VM. */
-#define VM_ENABLE_ASSERTIONS
+/* #define VM_ENABLE_ASSERTIONS */
-/* #define VM_ENABLE_PARANOID_ASSERTIONS */
+static void vm_expand_stack (struct scm_vm *vp, SCM *new_sp) SCM_NOINLINE;
+
+/* RESTORE is for the case where we know we have done a PUSH of equal or
+ greater stack size in the past. Otherwise PUSH is the thing, which
+ may expand the stack. */
+enum vm_increase_sp_kind { VM_SP_PUSH, VM_SP_RESTORE };
+
+static inline void
+vm_increase_sp (struct scm_vm *vp, SCM *new_sp, enum vm_increase_sp_kind kind)
+{
+ if (new_sp <= vp->sp_max_since_gc)
+ {
+ vp->sp = new_sp;
+ return;
+ }
-/* When defined, arrange so that the GC doesn't scan the VM stack beyond its
- current SP. This should help avoid excess data retention. See
- http://thread.gmane.org/gmane.comp.programming.garbage-collection.boehmgc/3001
- for a discussion. */
-#define VM_ENABLE_PRECISE_STACK_GC_SCAN
+ if (kind == VM_SP_PUSH && new_sp >= vp->stack_limit)
+ vm_expand_stack (vp, new_sp);
+ else
+ vp->sp_max_since_gc = vp->sp = new_sp;
+}
-/* Size in SCM objects of the stack reserve. The reserve is used to run
- exception handling code in case of a VM stack overflow. */
-#define VM_STACK_RESERVE_SIZE 512
+static inline void
+vm_push_sp (struct scm_vm *vp, SCM *new_sp)
+{
+ vm_increase_sp (vp, new_sp, VM_SP_PUSH);
+}
+static inline void
+vm_restore_sp (struct scm_vm *vp, SCM *new_sp)
+{
+ vm_increase_sp (vp, new_sp, VM_SP_RESTORE);
+}
\f
/*
scm_puts_unlocked (">", port);
}
-/* In theory, a number of vm instances can be active in the call trace, and we
- only want to reify the continuations of those in the current continuation
- root. I don't see a nice way to do this -- ideally it would involve dynwinds,
- and previous values of the *the-vm* fluid within the current continuation
- root. But we don't have access to continuation roots in the dynwind stack.
- So, just punt for now, we just capture the continuation for the current VM.
+int
+scm_i_vm_cont_to_frame (SCM cont, struct scm_frame *frame)
+{
+ struct scm_vm_cont *data = SCM_VM_CONT_DATA (cont);
- While I'm on the topic, ideally we could avoid copying the C stack if the
- continuation root is inside VM code, and call/cc was invoked within that same
- call to vm_run; but that's currently not implemented.
- */
+ frame->stack_holder = data;
+ frame->fp_offset = (data->fp + data->reloc) - data->stack_base;
+ frame->sp_offset = (data->sp + data->reloc) - data->stack_base;
+ frame->ip = data->ra;
+
+ return 1;
+}
+
+/* Ideally we could avoid copying the C stack if the continuation root
+ is inside VM code, and call/cc was invoked within that same call to
+ vm_run. That's currently not implemented. */
SCM
scm_i_vm_capture_stack (SCM *stack_base, SCM *fp, SCM *sp, scm_t_uint32 *ra,
scm_t_dynstack *dynstack, scm_t_uint32 flags)
return scm_cell (scm_tc7_vm_cont, (scm_t_bits)p);
}
+struct return_to_continuation_data
+{
+ struct scm_vm_cont *cp;
+ struct scm_vm *vp;
+};
+
+/* Called with the GC lock to prevent the stack marker from traversing a
+ stack in an inconsistent state. */
+static void *
+vm_return_to_continuation_inner (void *data_ptr)
+{
+ struct return_to_continuation_data *data = data_ptr;
+ struct scm_vm *vp = data->vp;
+ struct scm_vm_cont *cp = data->cp;
+ scm_t_ptrdiff reloc;
+
+ /* We know that there is enough space for the continuation, because we
+ captured it in the past. However there may have been an expansion
+ since the capture, so we may have to re-link the frame
+ pointers. */
+ reloc = (vp->stack_base - (cp->stack_base - cp->reloc));
+ vp->fp = cp->fp + reloc;
+ memcpy (vp->stack_base, cp->stack_base, cp->stack_size * sizeof (SCM));
+ vm_restore_sp (vp, cp->sp + reloc);
+
+ if (reloc)
+ {
+ SCM *fp = vp->fp;
+ while (fp)
+ {
+ SCM *next_fp = SCM_FRAME_DYNAMIC_LINK (fp);
+ if (next_fp)
+ {
+ next_fp += reloc;
+ SCM_FRAME_SET_DYNAMIC_LINK (fp, next_fp);
+ }
+ fp = next_fp;
+ }
+ }
+
+ return NULL;
+}
+
static void
vm_return_to_continuation (struct scm_vm *vp, SCM cont, size_t n, SCM *argv)
{
struct scm_vm_cont *cp;
SCM *argv_copy;
+ struct return_to_continuation_data data;
argv_copy = alloca (n * sizeof(SCM));
memcpy (argv_copy, argv, n * sizeof(SCM));
cp = SCM_VM_CONT_DATA (cont);
- if (vp->stack_size < cp->stack_size + n + 3)
- scm_misc_error ("vm-engine", "not enough space to reinstate continuation",
- scm_list_1 (cont));
+ data.cp = cp;
+ data.vp = vp;
+ GC_call_with_alloc_lock (vm_return_to_continuation_inner, &data);
- vp->sp = cp->sp;
- vp->fp = cp->fp;
- memcpy (vp->stack_base, cp->stack_base, cp->stack_size * sizeof (SCM));
+ /* Now we have the continuation properly copied over. We just need to
+ copy the arguments. It is not guaranteed that there is actually
+ space for the arguments, though, so we have to bump the SP first. */
+ vm_push_sp (vp, vp->sp + 3 + n);
+ /* Now copy on an empty frame and the return values, as the
+ continuation expects. */
{
+ SCM *base = vp->sp + 1 - 3 - n;
size_t i;
- /* Push on an empty frame, as the continuation expects. */
for (i = 0; i < 3; i++)
- {
- vp->sp++;
- *vp->sp = SCM_BOOL_F;
- }
+ base[i] = SCM_BOOL_F;
- /* Push the return values. */
for (i = 0; i < n; i++)
- {
- vp->sp++;
- *vp->sp = argv_copy[i];
- }
- vp->ip = cp->ra;
+ base[i + 3] = argv_copy[i];
}
+
+ vp->ip = cp->ra;
}
+static struct scm_vm * thread_vm (scm_i_thread *t);
SCM
scm_i_capture_current_stack (void)
{
struct scm_vm *vp;
thread = SCM_I_CURRENT_THREAD;
- vp = scm_the_vm ();
+ vp = thread_vm (thread);
return scm_i_vm_capture_stack (vp->stack_base, vp->fp, vp->sp, vp->ip,
scm_dynstack_capture_all (&thread->dynstack),
static void vm_dispatch_pop_continuation_hook (struct scm_vm *vp, SCM *old_fp) SCM_NOINLINE;
static void vm_dispatch_next_hook (struct scm_vm *vp) SCM_NOINLINE;
static void vm_dispatch_abort_hook (struct scm_vm *vp) SCM_NOINLINE;
-static void vm_dispatch_restore_continuation_hook (struct scm_vm *vp) SCM_NOINLINE;
static void
vm_dispatch_hook (struct scm_vm *vp, int hook_num, SCM *argv, int n)
&SCM_FRAME_LOCAL (vp->fp, 1),
SCM_FRAME_NUM_LOCALS (vp->fp, vp->sp) - 1);
}
-static void vm_dispatch_restore_continuation_hook (struct scm_vm *vp)
-{
- return vm_dispatch_hook (vp, SCM_VM_RESTORE_CONTINUATION_HOOK, NULL, 0);
-}
static void
vm_abort (struct scm_vm *vp, SCM tag,
for (; i < nstack + tail_len; i++, tail = scm_cdr (tail))
argv[i] = scm_car (tail);
- /* FIXME: NULLSTACK (SCM_VM_DATA (vp)->sp - sp) */
vp->sp = sp;
scm_c_abort (vp, tag, nstack + tail_len, argv, current_registers);
}
-static void
-vm_reinstate_partial_continuation (struct scm_vm *vp, SCM cont,
- size_t n, SCM *argv,
- scm_t_dynstack *dynstack,
- scm_i_jmp_buf *registers)
+struct vm_reinstate_partial_continuation_data
{
+ struct scm_vm *vp;
struct scm_vm_cont *cp;
- SCM *argv_copy, *base;
scm_t_ptrdiff reloc;
- size_t i;
+};
- argv_copy = alloca (n * sizeof(SCM));
- memcpy (argv_copy, argv, n * sizeof(SCM));
+static void *
+vm_reinstate_partial_continuation_inner (void *data_ptr)
+{
+ struct vm_reinstate_partial_continuation_data *data = data_ptr;
+ struct scm_vm *vp = data->vp;
+ struct scm_vm_cont *cp = data->cp;
+ SCM *base;
+ scm_t_ptrdiff reloc;
- cp = SCM_VM_CONT_DATA (cont);
base = SCM_FRAME_LOCALS_ADDRESS (vp->fp);
reloc = cp->reloc + (base - cp->stack_base);
-#define RELOC(scm_p) \
- (((SCM *) (scm_p)) + reloc)
-
- if ((base - vp->stack_base) + cp->stack_size + n + 1 > vp->stack_size)
- scm_misc_error ("vm-engine",
- "not enough space to instate partial continuation",
- scm_list_1 (cont));
-
memcpy (base, cp->stack_base, cp->stack_size * sizeof (SCM));
+ vp->fp = cp->fp + reloc;
+ vp->ip = cp->ra;
+
/* now relocate frame pointers */
{
SCM *fp;
- for (fp = RELOC (cp->fp);
- SCM_FRAME_LOWER_ADDRESS (fp) > base;
+ for (fp = vp->fp;
+ SCM_FRAME_LOWER_ADDRESS (fp) >= base;
fp = SCM_FRAME_DYNAMIC_LINK (fp))
- SCM_FRAME_SET_DYNAMIC_LINK (fp, RELOC (SCM_FRAME_DYNAMIC_LINK (fp)));
+ SCM_FRAME_SET_DYNAMIC_LINK (fp, SCM_FRAME_DYNAMIC_LINK (fp) + reloc);
}
- vp->sp = base - 1 + cp->stack_size;
- vp->fp = RELOC (cp->fp);
- vp->ip = cp->ra;
+ data->reloc = reloc;
+
+ return NULL;
+}
+
+static void
+vm_reinstate_partial_continuation (struct scm_vm *vp, SCM cont,
+ size_t n, SCM *argv,
+ scm_t_dynstack *dynstack,
+ scm_i_jmp_buf *registers)
+{
+ struct vm_reinstate_partial_continuation_data data;
+ struct scm_vm_cont *cp;
+ SCM *argv_copy;
+ scm_t_ptrdiff reloc;
+ size_t i;
+
+ argv_copy = alloca (n * sizeof(SCM));
+ memcpy (argv_copy, argv, n * sizeof(SCM));
+
+ cp = SCM_VM_CONT_DATA (cont);
+
+ vm_push_sp (vp, SCM_FRAME_LOCALS_ADDRESS (vp->fp) + cp->stack_size + n - 1);
+
+ data.vp = vp;
+ data.cp = cp;
+ GC_call_with_alloc_lock (vm_reinstate_partial_continuation_inner, &data);
+ reloc = data.reloc;
/* Push the arguments. */
for (i = 0; i < n; i++)
- {
- vp->sp++;
- *vp->sp = argv_copy[i];
- }
+ vp->sp[i + 1 - n] = argv_copy[i];
/* The prompt captured a slice of the dynamic stack. Here we wind
those entries onto the current thread's stack. We also have to
scm_dynstack_wind_1 (dynstack, walk);
}
}
-#undef RELOC
-}
-
-\f
-/*
- * VM Internal functions
- */
-
-void
-scm_i_vm_print (SCM x, SCM port, scm_print_state *pstate)
-{
- const struct scm_vm *vm;
-
- vm = SCM_VM_DATA (x);
-
- scm_puts_unlocked ("#<vm ", port);
- switch (vm->engine)
- {
- case SCM_VM_REGULAR_ENGINE:
- scm_puts_unlocked ("regular-engine ", port);
- break;
-
- case SCM_VM_DEBUG_ENGINE:
- scm_puts_unlocked ("debug-engine ", port);
- break;
-
- default:
- scm_puts_unlocked ("unknown-engine ", port);
- }
- scm_uintprint (SCM_UNPACK (x), 16, port);
- scm_puts_unlocked (">", port);
}
\f
static void vm_error (const char *msg, SCM arg) SCM_NORETURN;
static void vm_error_bad_instruction (scm_t_uint32 inst) SCM_NORETURN SCM_NOINLINE;
-static void vm_error_unbound (SCM proc, SCM sym) SCM_NORETURN SCM_NOINLINE;
-static void vm_error_unbound_fluid (SCM proc, SCM fluid) SCM_NORETURN SCM_NOINLINE;
+static void vm_error_unbound (SCM sym) SCM_NORETURN SCM_NOINLINE;
+static void vm_error_unbound_fluid (SCM fluid) SCM_NORETURN SCM_NOINLINE;
static void vm_error_not_a_variable (const char *func_name, SCM x) SCM_NORETURN SCM_NOINLINE;
static void vm_error_apply_to_non_list (SCM x) SCM_NORETURN SCM_NOINLINE;
static void vm_error_kwargs_length_not_even (SCM proc) SCM_NORETURN SCM_NOINLINE;
static void vm_error_too_many_args (int nargs) SCM_NORETURN SCM_NOINLINE;
static void vm_error_wrong_num_args (SCM proc) SCM_NORETURN SCM_NOINLINE;
static void vm_error_wrong_type_apply (SCM proc) SCM_NORETURN SCM_NOINLINE;
-static void vm_error_stack_overflow (struct scm_vm *vp) SCM_NORETURN SCM_NOINLINE;
static void vm_error_stack_underflow (void) SCM_NORETURN SCM_NOINLINE;
static void vm_error_improper_list (SCM x) SCM_NORETURN SCM_NOINLINE;
static void vm_error_not_a_pair (const char *subr, SCM x) SCM_NORETURN SCM_NOINLINE;
static void vm_error_not_a_bytevector (const char *subr, SCM x) SCM_NORETURN SCM_NOINLINE;
static void vm_error_not_a_struct (const char *subr, SCM x) SCM_NORETURN SCM_NOINLINE;
+static void vm_error_not_a_vector (const char *subr, SCM v) SCM_NORETURN SCM_NOINLINE;
+static void vm_error_out_of_range (const char *subr, SCM k) SCM_NORETURN SCM_NOINLINE;
static void vm_error_no_values (void) SCM_NORETURN SCM_NOINLINE;
static void vm_error_not_enough_values (void) SCM_NORETURN SCM_NOINLINE;
static void vm_error_wrong_number_of_values (scm_t_uint32 expected) SCM_NORETURN SCM_NOINLINE;
}
static void
-vm_error_unbound (SCM proc, SCM sym)
+vm_error_unbound (SCM sym)
{
- scm_error_scm (scm_misc_error_key, proc,
+ scm_error_scm (scm_misc_error_key, SCM_BOOL_F,
scm_from_latin1_string ("Unbound variable: ~s"),
scm_list_1 (sym), SCM_BOOL_F);
}
static void
-vm_error_unbound_fluid (SCM proc, SCM fluid)
+vm_error_unbound_fluid (SCM fluid)
{
- scm_error_scm (scm_misc_error_key, proc,
+ scm_error_scm (scm_misc_error_key, SCM_BOOL_F,
scm_from_latin1_string ("Unbound fluid: ~s"),
scm_list_1 (fluid), SCM_BOOL_F);
}
scm_list_1 (proc), scm_list_1 (proc));
}
-static void
-vm_error_stack_overflow (struct scm_vm *vp)
-{
- if (vp->stack_limit < vp->stack_base + vp->stack_size)
- /* There are VM_STACK_RESERVE_SIZE bytes left. Make them available so
- that `throw' below can run on this VM. */
- vp->stack_limit = vp->stack_base + vp->stack_size;
- else
- /* There is no space left on the stack. FIXME: Do something more
- sensible here! */
- abort ();
- vm_error ("VM: Stack overflow", SCM_UNDEFINED);
-}
-
static void
vm_error_stack_underflow (void)
{
scm_wrong_type_arg_msg (subr, 1, x, "struct");
}
+static void
+vm_error_not_a_vector (const char *subr, SCM x)
+{
+ scm_wrong_type_arg_msg (subr, 1, x, "vector");
+}
+
+static void
+vm_error_out_of_range (const char *subr, SCM k)
+{
+ scm_to_size_t (k);
+ scm_out_of_range (subr, k);
+}
+
static void
vm_error_no_values (void)
{
* VM
*/
-#define VM_MIN_STACK_SIZE (1024)
-#define VM_DEFAULT_STACK_SIZE (256 * 1024)
-static size_t vm_stack_size = VM_DEFAULT_STACK_SIZE;
-
-static void
-initialize_default_stack_size (void)
-{
- int size = scm_getenv_int ("GUILE_STACK_SIZE", vm_stack_size);
- if (size >= VM_MIN_STACK_SIZE)
- vm_stack_size = size;
-}
-
#define VM_NAME vm_regular_engine
#define VM_USE_HOOKS 0
#define FUNC_NAME "vm-regular-engine"
#undef VM_USE_HOOKS
#undef VM_NAME
-typedef SCM (*scm_t_vm_engine) (struct scm_vm *vp,
- SCM program, SCM *argv, size_t nargs);
+typedef SCM (*scm_t_vm_engine) (scm_i_thread *current_thread, struct scm_vm *vp,
+ scm_i_jmp_buf *registers, int resume);
static const scm_t_vm_engine vm_engines[SCM_VM_NUM_ENGINES] =
{ vm_regular_engine, vm_debug_engine };
-#ifdef VM_ENABLE_PRECISE_STACK_GC_SCAN
+static SCM*
+allocate_stack (size_t size)
+#define FUNC_NAME "make_vm"
+{
+ void *ret;
+
+ if (size >= ((size_t) -1) / sizeof (SCM))
+ abort ();
-/* The GC "kind" for the VM stack. */
-static int vm_stack_gc_kind;
+ size *= sizeof (SCM);
+#if HAVE_SYS_MMAN_H
+ ret = mmap (NULL, size, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ if (ret == MAP_FAILED)
+ ret = NULL;
+#else
+ ret = malloc (size);
#endif
-static SCM
-make_vm (void)
-#define FUNC_NAME "make_vm"
+ if (!ret)
+ {
+ perror ("allocate_stack failed");
+ return NULL;
+ }
+
+ return (SCM *) ret;
+}
+#undef FUNC_NAME
+
+static void
+free_stack (SCM *stack, size_t size)
{
- int i;
- struct scm_vm *vp;
+ size *= sizeof (SCM);
- vp = scm_gc_malloc (sizeof (struct scm_vm), "vm");
+#if HAVE_SYS_MMAN_H
+ munmap (stack, size);
+#else
+ free (stack);
+#endif
+}
+
+static SCM*
+expand_stack (SCM *old_stack, size_t old_size, size_t new_size)
+#define FUNC_NAME "expand_stack"
+{
+#if defined MREMAP_MAYMOVE
+ void *new_stack;
+
+ if (new_size >= ((size_t) -1) / sizeof (SCM))
+ abort ();
- vp->stack_size= vm_stack_size;
+ old_size *= sizeof (SCM);
+ new_size *= sizeof (SCM);
-#ifdef VM_ENABLE_PRECISE_STACK_GC_SCAN
- vp->stack_base = (SCM *)
- GC_generic_malloc (vp->stack_size * sizeof (SCM), vm_stack_gc_kind);
+ new_stack = mremap (old_stack, old_size, new_size, MREMAP_MAYMOVE);
+ if (new_stack == MAP_FAILED)
+ return NULL;
- /* Keep a pointer to VP so that `vm_stack_mark ()' can know what the stack
- top is. */
- *vp->stack_base = SCM_PACK_POINTER (vp);
- vp->stack_base++;
- vp->stack_size--;
+ return (SCM *) new_stack;
#else
- vp->stack_base = scm_gc_malloc (vp->stack_size * sizeof (SCM),
- "stack-base");
+ SCM *new_stack;
+
+ new_stack = allocate_stack (new_size);
+ if (!new_stack)
+ return NULL;
+
+ memcpy (new_stack, old_stack, old_size * sizeof (SCM));
+ free_stack (old_stack, old_size);
+
+ return new_stack;
#endif
+}
+#undef FUNC_NAME
+
+static struct scm_vm *
+make_vm (void)
+#define FUNC_NAME "make_vm"
+{
+ int i;
+ struct scm_vm *vp;
- vp->stack_limit = vp->stack_base + vp->stack_size - VM_STACK_RESERVE_SIZE;
+ vp = scm_gc_malloc (sizeof (struct scm_vm), "vm");
+
+ vp->stack_size = page_size / sizeof (SCM);
+ vp->stack_base = allocate_stack (vp->stack_size);
+ if (!vp->stack_base)
+ /* As in expand_stack, we don't have any way to throw an exception
+ if we can't allocate one measely page -- there's no stack to
+ handle it. For now, abort. */
+ abort ();
+ vp->stack_limit = vp->stack_base + vp->stack_size;
+ vp->overflow_handler_stack = SCM_EOL;
vp->ip = NULL;
vp->sp = vp->stack_base - 1;
vp->fp = NULL;
vp->trace_level = 0;
for (i = 0; i < SCM_VM_NUM_HOOKS; i++)
vp->hooks[i] = SCM_BOOL_F;
- return scm_cell (scm_tc7_vm, (scm_t_bits)vp);
+
+ return vp;
}
#undef FUNC_NAME
-#ifdef VM_ENABLE_PRECISE_STACK_GC_SCAN
+static void
+return_unused_stack_to_os (struct scm_vm *vp)
+{
+#if HAVE_SYS_MMAN_H
+ scm_t_uintptr start = (scm_t_uintptr) (vp->sp + 1);
+ scm_t_uintptr end = (scm_t_uintptr) vp->stack_limit;
+ /* The second condition is needed to protect against wrap-around. */
+ if (vp->sp_max_since_gc < vp->stack_limit && vp->sp < vp->sp_max_since_gc)
+ end = (scm_t_uintptr) (vp->sp_max_since_gc + 1);
-/* Mark the VM stack region between its base and its current top. */
-static struct GC_ms_entry *
-vm_stack_mark (GC_word *addr, struct GC_ms_entry *mark_stack_ptr,
- struct GC_ms_entry *mark_stack_limit, GC_word env)
+ start = ((start - 1U) | (page_size - 1U)) + 1U; /* round up */
+ end = ((end - 1U) | (page_size - 1U)) + 1U; /* round up */
+
+ /* Return these pages to the OS. The next time they are paged in,
+ they will be zeroed. */
+ if (start < end)
+ {
+ int ret = 0;
+
+ do
+ ret = madvise ((void *) start, end - start, MADV_DONTNEED);
+ while (ret && errno == -EAGAIN);
+
+ if (ret)
+ perror ("madvise failed");
+ }
+
+ vp->sp_max_since_gc = vp->sp;
+#endif
+}
+
+#define DEAD_SLOT_MAP_CACHE_SIZE 32U
+struct dead_slot_map_cache_entry
{
- GC_word *word;
- const struct scm_vm *vm;
+ scm_t_uint32 *ip;
+ const scm_t_uint8 *map;
+};
- /* The first word of the VM stack should contain a pointer to the
- corresponding VM. */
- vm = * ((struct scm_vm **) addr);
+struct dead_slot_map_cache
+{
+ struct dead_slot_map_cache_entry entries[DEAD_SLOT_MAP_CACHE_SIZE];
+};
- if (vm == NULL
- || (SCM *) addr != vm->stack_base - 1)
- /* ADDR must be a pointer to a free-list element, which we must ignore
- (see warning in <gc/gc_mark.h>). */
- return mark_stack_ptr;
+static const scm_t_uint8 *
+find_dead_slot_map (scm_t_uint32 *ip, struct dead_slot_map_cache *cache)
+{
+ /* The lower two bits should be zero. FIXME: Use a better hash
+ function; we don't expose scm_raw_hashq currently. */
+ size_t slot = (((scm_t_uintptr) ip) >> 2) % DEAD_SLOT_MAP_CACHE_SIZE;
+ const scm_t_uint8 *map;
- for (word = (GC_word *) vm->stack_base; word <= (GC_word *) vm->sp; word++)
- mark_stack_ptr = GC_MARK_AND_PUSH ((* (GC_word **) word),
- mark_stack_ptr, mark_stack_limit,
- NULL);
+ if (cache->entries[slot].ip == ip)
+ map = cache->entries[slot].map;
+ else
+ {
+ map = scm_find_dead_slot_map_unlocked (ip);
+ cache->entries[slot].ip = ip;
+ cache->entries[slot].map = map;
+ }
+
+ return map;
+}
+
+/* Mark the VM stack region between its base and its current top. */
+struct GC_ms_entry *
+scm_i_vm_mark_stack (struct scm_vm *vp, struct GC_ms_entry *mark_stack_ptr,
+ struct GC_ms_entry *mark_stack_limit)
+{
+ SCM *sp, *fp;
+ /* The first frame will be marked conservatively (without a dead
+ slot map). This is because GC can happen at any point within the
+ hottest activation, due to multiple threads or per-instruction
+ hooks, and providing dead slot maps for all points in a program
+ would take a prohibitive amount of space. */
+ const scm_t_uint8 *dead_slots = NULL;
+ scm_t_uintptr upper = (scm_t_uintptr) GC_greatest_plausible_heap_addr;
+ scm_t_uintptr lower = (scm_t_uintptr) GC_least_plausible_heap_addr;
+ struct dead_slot_map_cache cache;
+
+ memset (&cache, 0, sizeof (cache));
+
+ for (fp = vp->fp, sp = vp->sp; fp; fp = SCM_FRAME_DYNAMIC_LINK (fp))
+ {
+ for (; sp >= &SCM_FRAME_LOCAL (fp, 0); sp--)
+ {
+ SCM elt = *sp;
+ if (SCM_NIMP (elt)
+ && SCM_UNPACK (elt) >= lower && SCM_UNPACK (elt) <= upper)
+ {
+ if (dead_slots)
+ {
+ size_t slot = sp - &SCM_FRAME_LOCAL (fp, 0);
+ if (dead_slots[slot / 8U] & (1U << (slot % 8U)))
+ {
+ /* This value may become dead as a result of GC,
+ so we can't just leave it on the stack. */
+ *sp = SCM_UNSPECIFIED;
+ continue;
+ }
+ }
+
+ mark_stack_ptr = GC_mark_and_push ((void *) elt,
+ mark_stack_ptr,
+ mark_stack_limit,
+ NULL);
+ }
+ }
+ sp = SCM_FRAME_PREVIOUS_SP (fp);
+ /* Inner frames may have a dead slots map for precise marking.
+ Note that there may be other reasons to not have a dead slots
+ map, e.g. if all of the frame's slots below the callee frame
+ are live. */
+ dead_slots = find_dead_slot_map (SCM_FRAME_RETURN_ADDRESS (fp), &cache);
+ }
+
+ return_unused_stack_to_os (vp);
return mark_stack_ptr;
}
-#endif /* VM_ENABLE_PRECISE_STACK_GC_SCAN */
+/* Free the VM stack, as this thread is exiting. */
+void
+scm_i_vm_free_stack (struct scm_vm *vp)
+{
+ free_stack (vp->stack_base, vp->stack_size);
+ vp->stack_base = vp->stack_limit = NULL;
+ vp->stack_size = 0;
+}
+struct vm_expand_stack_data
+{
+ struct scm_vm *vp;
+ size_t stack_size;
+ SCM *new_sp;
+};
-SCM
-scm_call_n (SCM proc, SCM *argv, size_t nargs)
+static void *
+vm_expand_stack_inner (void *data_ptr)
{
- struct scm_vm *vp = scm_the_vm ();
- SCM_CHECK_STACK;
- return vm_engines[vp->engine](vp, proc, argv, nargs);
+ struct vm_expand_stack_data *data = data_ptr;
+
+ struct scm_vm *vp = data->vp;
+ SCM *old_stack, *new_stack;
+ size_t new_size;
+ scm_t_ptrdiff reloc;
+
+ new_size = vp->stack_size;
+ while (new_size < data->stack_size)
+ new_size *= 2;
+ old_stack = vp->stack_base;
+
+ new_stack = expand_stack (vp->stack_base, vp->stack_size, new_size);
+ if (!new_stack)
+ return NULL;
+
+ vp->stack_base = new_stack;
+ vp->stack_size = new_size;
+ vp->stack_limit = vp->stack_base + new_size;
+ reloc = vp->stack_base - old_stack;
+
+ if (reloc)
+ {
+ SCM *fp;
+ if (vp->fp)
+ vp->fp += reloc;
+ data->new_sp += reloc;
+ fp = vp->fp;
+ while (fp)
+ {
+ SCM *next_fp = SCM_FRAME_DYNAMIC_LINK (fp);
+ if (next_fp)
+ {
+ next_fp += reloc;
+ SCM_FRAME_SET_DYNAMIC_LINK (fp, next_fp);
+ }
+ fp = next_fp;
+ }
+ }
+
+ return new_stack;
+}
+
+static scm_t_ptrdiff
+current_overflow_size (struct scm_vm *vp)
+{
+ if (scm_is_pair (vp->overflow_handler_stack))
+ return scm_to_ptrdiff_t (scm_caar (vp->overflow_handler_stack));
+ return -1;
+}
+
+static int
+should_handle_stack_overflow (struct scm_vm *vp, scm_t_ptrdiff stack_size)
+{
+ scm_t_ptrdiff overflow_size = current_overflow_size (vp);
+ return overflow_size >= 0 && stack_size >= overflow_size;
+}
+
+static void
+reset_stack_limit (struct scm_vm *vp)
+{
+ if (should_handle_stack_overflow (vp, vp->stack_size))
+ vp->stack_limit = vp->stack_base + current_overflow_size (vp);
+ else
+ vp->stack_limit = vp->stack_base + vp->stack_size;
+}
+
+struct overflow_handler_data
+{
+ struct scm_vm *vp;
+ SCM overflow_handler_stack;
+};
+
+static void
+wind_overflow_handler (void *ptr)
+{
+ struct overflow_handler_data *data = ptr;
+
+ data->vp->overflow_handler_stack = data->overflow_handler_stack;
+
+ reset_stack_limit (data->vp);
+}
+
+static void
+unwind_overflow_handler (void *ptr)
+{
+ struct overflow_handler_data *data = ptr;
+
+ data->vp->overflow_handler_stack = scm_cdr (data->overflow_handler_stack);
+
+ reset_stack_limit (data->vp);
+}
+
+static void
+vm_expand_stack (struct scm_vm *vp, SCM *new_sp)
+{
+ scm_t_ptrdiff stack_size = new_sp + 1 - vp->stack_base;
+
+ if (stack_size > vp->stack_size)
+ {
+ struct vm_expand_stack_data data;
+
+ data.vp = vp;
+ data.stack_size = stack_size;
+ data.new_sp = new_sp;
+
+ if (!GC_call_with_alloc_lock (vm_expand_stack_inner, &data))
+ /* Throw an unwind-only exception. */
+ scm_report_stack_overflow ();
+
+ new_sp = data.new_sp;
+ }
+
+ vp->sp_max_since_gc = vp->sp = new_sp;
+
+ if (should_handle_stack_overflow (vp, stack_size))
+ {
+ SCM more_stack, new_limit;
+
+ struct overflow_handler_data data;
+ data.vp = vp;
+ data.overflow_handler_stack = vp->overflow_handler_stack;
+
+ scm_dynwind_begin (SCM_F_DYNWIND_REWINDABLE);
+
+ scm_dynwind_rewind_handler (unwind_overflow_handler, &data,
+ SCM_F_WIND_EXPLICITLY);
+ scm_dynwind_unwind_handler (wind_overflow_handler, &data,
+ SCM_F_WIND_EXPLICITLY);
+
+ /* Call the overflow handler. */
+ more_stack = scm_call_0 (scm_cdar (data.overflow_handler_stack));
+
+ /* If the overflow handler returns, its return value should be an
+ integral number of words from the outer stack limit to transfer
+ to the inner limit. */
+ if (scm_to_ptrdiff_t (more_stack) <= 0)
+ scm_out_of_range (NULL, more_stack);
+ new_limit = scm_sum (scm_caar (data.overflow_handler_stack), more_stack);
+ if (scm_is_pair (scm_cdr (data.overflow_handler_stack)))
+ new_limit = scm_min (new_limit,
+ scm_caadr (data.overflow_handler_stack));
+
+ /* Ensure the new limit is in range. */
+ scm_to_ptrdiff_t (new_limit);
+
+ /* Increase the limit that we will restore. */
+ scm_set_car_x (scm_car (data.overflow_handler_stack), new_limit);
+
+ scm_dynwind_end ();
+
+ /* Recurse */
+ return vm_expand_stack (vp, new_sp);
+ }
+}
+
+static struct scm_vm *
+thread_vm (scm_i_thread *t)
+{
+ if (SCM_UNLIKELY (!t->vp))
+ t->vp = make_vm ();
+
+ return t->vp;
}
struct scm_vm *
scm_the_vm (void)
{
- scm_i_thread *t = SCM_I_CURRENT_THREAD;
+ return thread_vm (SCM_I_CURRENT_THREAD);
+}
- if (SCM_UNLIKELY (scm_is_false (t->vm)))
- t->vm = make_vm ();
+SCM
+scm_call_n (SCM proc, SCM *argv, size_t nargs)
+{
+ scm_i_thread *thread;
+ struct scm_vm *vp;
+ SCM *base;
+ ptrdiff_t base_frame_size;
+ /* Cached variables. */
+ scm_i_jmp_buf registers; /* used for prompts */
+ size_t i;
+
+ thread = SCM_I_CURRENT_THREAD;
+ vp = thread_vm (thread);
+
+ SCM_CHECK_STACK;
+
+ /* Check that we have enough space: 3 words for the boot continuation,
+ and 3 + nargs for the procedure application. */
+ base_frame_size = 3 + 3 + nargs;
+ vm_push_sp (vp, vp->sp + base_frame_size);
+ base = vp->sp + 1 - base_frame_size;
+
+ /* Since it's possible to receive the arguments on the stack itself,
+ shuffle up the arguments first. */
+ for (i = nargs; i > 0; i--)
+ base[6 + i - 1] = argv[i - 1];
+
+ /* Push the boot continuation, which calls PROC and returns its
+ result(s). */
+ base[0] = SCM_PACK (vp->fp); /* dynamic link */
+ base[1] = SCM_PACK (vp->ip); /* ra */
+ base[2] = vm_boot_continuation;
+ vp->fp = &base[2];
+ vp->ip = (scm_t_uint32 *) vm_boot_continuation_code;
+
+ /* The pending call to PROC. */
+ base[3] = SCM_PACK (vp->fp); /* dynamic link */
+ base[4] = SCM_PACK (vp->ip); /* ra */
+ base[5] = proc;
+ vp->fp = &base[5];
+
+ {
+ int resume = SCM_I_SETJMP (registers);
+
+ if (SCM_UNLIKELY (resume))
+ {
+ scm_gc_after_nonlocal_exit ();
+ /* Non-local return. */
+ vm_dispatch_abort_hook (vp);
+ }
- return SCM_VM_DATA (t->vm);
+ return vm_engines[vp->engine](thread, vp, ®isters, resume);
+ }
}
/* Scheme interface */
}
#undef FUNC_NAME
-SCM_DEFINE (scm_vm_restore_continuation_hook, "vm-restore-continuation-hook", 0, 0, 0,
- (void),
- "")
-#define FUNC_NAME s_scm_vm_restore_continuation_hook
-{
- VM_DEFINE_HOOK (SCM_VM_RESTORE_CONTINUATION_HOOK);
-}
-#undef FUNC_NAME
-
SCM_DEFINE (scm_vm_trace_level, "vm-trace-level", 0, 0, 0,
(void),
"")
}
#undef FUNC_NAME
+SCM_DEFINE (scm_call_with_stack_overflow_handler,
+ "call-with-stack-overflow-handler", 3, 0, 0,
+ (SCM limit, SCM thunk, SCM handler),
+ "Call @var{thunk} in an environment in which the stack limit has\n"
+ "been reduced to @var{limit} additional words. If the limit is\n"
+ "reached, @var{handler} (a thunk) will be invoked in the dynamic\n"
+ "environment of the error. For the extent of the call to\n"
+ "@var{handler}, the stack limit and handler are restored to the\n"
+ "values that were in place when\n"
+ "@code{call-with-stack-overflow-handler} was called.")
+#define FUNC_NAME s_scm_call_with_stack_overflow_handler
+{
+ struct scm_vm *vp;
+ scm_t_ptrdiff c_limit, stack_size;
+ struct overflow_handler_data data;
+ SCM new_limit, ret;
+
+ vp = scm_the_vm ();
+ stack_size = vp->sp - vp->stack_base;
+
+ c_limit = scm_to_ptrdiff_t (limit);
+ if (c_limit <= 0)
+ scm_out_of_range (FUNC_NAME, limit);
+
+ new_limit = scm_sum (scm_from_ptrdiff_t (stack_size), limit);
+ if (scm_is_pair (vp->overflow_handler_stack))
+ new_limit = scm_min (new_limit, scm_caar (vp->overflow_handler_stack));
+
+ /* Hacky check that the current stack depth plus the limit is within
+ the range of a ptrdiff_t. */
+ scm_to_ptrdiff_t (new_limit);
+
+ data.vp = vp;
+ data.overflow_handler_stack =
+ scm_acons (limit, handler, vp->overflow_handler_stack);
+
+ scm_dynwind_begin (SCM_F_DYNWIND_REWINDABLE);
+
+ scm_dynwind_rewind_handler (wind_overflow_handler, &data,
+ SCM_F_WIND_EXPLICITLY);
+ scm_dynwind_unwind_handler (unwind_overflow_handler, &data,
+ SCM_F_WIND_EXPLICITLY);
+
+ /* Reset vp->sp_max_since_gc so that the VM checks actually
+ trigger. */
+ return_unused_stack_to_os (vp);
+
+ ret = scm_call_0 (thunk);
+
+ scm_dynwind_end ();
+
+ return ret;
+}
+#undef FUNC_NAME
+
\f
/*
* Initialize
(scm_t_extension_init_func)scm_init_vm_builtins,
NULL);
- initialize_default_stack_size ();
+ page_size = getpagesize ();
+ /* page_size should be a power of two. */
+ if (page_size & (page_size - 1))
+ abort ();
sym_vm_run = scm_from_latin1_symbol ("vm-run");
sym_vm_error = scm_from_latin1_symbol ("vm-error");
vm_builtin_##builtin = scm_i_make_program (vm_builtin_##builtin##_code);
FOR_EACH_VM_BUILTIN (DEFINE_BUILTIN);
#undef DEFINE_BUILTIN
-
-#ifdef VM_ENABLE_PRECISE_STACK_GC_SCAN
- vm_stack_gc_kind =
- GC_new_kind (GC_new_free_list (),
- GC_MAKE_PROC (GC_new_proc (vm_stack_mark), 0),
- 0, 1);
-
-#endif
}
void
HCoop / bpt / guile.git / blobdiff