/* emacs-module.c - Module loading and runtime implementation
-Copyright (C) 2015 Free Software Foundation, Inc.
+Copyright (C) 2015-2016 Free Software Foundation, Inc.
This file is part of GNU Emacs.
GNU Emacs is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
-the Free Software Foundation, either version 3 of the License, or
-(at your option) any later version.
+the Free Software Foundation, either version 3 of the License, or (at
+your option) any later version.
GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
\f
/* Feature tests. */
-/* True if __attribute__ ((cleanup (...))) works, false otherwise. */
-#ifdef HAVE_VAR_ATTRIBUTE_CLEANUP
+#if __has_attribute (cleanup)
enum { module_has_cleanup = true };
#else
enum { module_has_cleanup = false };
/* Handle to the main thread. Used to verify that modules call us in
the right thread. */
-#ifdef HAVE_THREADS_H
-# include <threads.h>
-static thrd_t main_thread;
-#elif defined HAVE_PTHREAD
+#ifdef HAVE_PTHREAD
# include <pthread.h>
static pthread_t main_thread;
#elif defined WINDOWSNT
static DWORD main_thread;
#endif
-\f
-/* Memory management. */
-
-/* An `emacs_value' is just a pointer to a structure holding an
- internal Lisp object. */
-struct emacs_value_tag { Lisp_Object v; };
-
-/* Local value objects use a simple fixed-sized block allocation
- scheme without explicit deallocation. All local values are
- deallocated when the lifetime of their environment ends. Keep
- track of a current frame from which new values are allocated,
- appending further dynamically-allocated frames if necessary. */
-
-enum { value_frame_size = 512 };
-
-/* A block from which `emacs_value' object can be allocated. */
-struct emacs_value_frame
-{
- /* Storage for values. */
- struct emacs_value_tag objects[value_frame_size];
-
- /* Index of the next free value in `objects'. */
- int offset;
-
- /* Pointer to next frame, if any. */
- struct emacs_value_frame *next;
-};
-
-/* A structure that holds an initial frame (so that the first local
- values require no dynamic allocation) and keeps track of the
- current frame. */
-static struct emacs_value_storage
-{
- struct emacs_value_frame initial;
- struct emacs_value_frame *current;
-} global_storage;
+/* True if Lisp_Object and emacs_value have the same representation.
+ This is typically true unless WIDE_EMACS_INT. In practice, having
+ the same sizes and alignments and maximums should be a good enough
+ proxy for equality of representation. */
+enum
+ {
+ plain_values
+ = (sizeof (Lisp_Object) == sizeof (emacs_value)
+ && alignof (Lisp_Object) == alignof (emacs_value)
+ && INTPTR_MAX == EMACS_INT_MAX)
+ };
+
+/* Function prototype for module user-pointer finalizers. These
+ should not throw C++ exceptions, so emacs-module.h declares the
+ corresponding interfaces with EMACS_NOEXCEPT. There is only C code
+ in this module, though, so this constraint is not enforced here. */
+typedef void (*emacs_finalizer_function) (void *);
\f
/* Private runtime and environment members. */
/* Dedicated storage for non-local exit symbol and data so that
storage is always available for them, even in an out-of-memory
situation. */
- struct emacs_value_tag non_local_exit_symbol, non_local_exit_data;
-
- struct emacs_value_storage storage;
+ Lisp_Object non_local_exit_symbol, non_local_exit_data;
};
/* The private parts of an `emacs_runtime' object contain the initial
struct emacs_runtime_private
{
/* FIXME: Ideally, we would just define "struct emacs_runtime_private"
- * as a synonym of "emacs_env", but I don't know how to do that in C. */
+ as a synonym of "emacs_env", but I don't know how to do that in C. */
emacs_env pub;
};
\f
static Lisp_Object module_format_fun_env (const struct module_fun_env *);
static Lisp_Object value_to_lisp (emacs_value);
-static emacs_value allocate_emacs_value (emacs_env *, struct emacs_value_storage *, Lisp_Object);
-static emacs_value lisp_to_value (emacs_env *, Lisp_Object);
+static emacs_value lisp_to_value (Lisp_Object);
static enum emacs_funcall_exit module_non_local_exit_check (emacs_env *);
static void check_main_thread (void);
static void finalize_environment (struct emacs_env_private *);
static void module_reset_handlerlist (const int *);
static void module_wrong_type (emacs_env *, Lisp_Object, Lisp_Object);
+/* We used to return NULL when emacs_value was a different type from
+ Lisp_Object, but nowadays we just use Qnil instead. Although they
+ happen to be the same thing in the current implementation, module
+ code should not assume this. */
+verify (NIL_IS_ZERO);
+static emacs_value const module_nil = 0;
\f
/* Convenience macros for non-local exit handling. */
+/* FIXME: The following implementation for non-local exit handling
+ does not support recovery from stack overflow, see sysdep.c. */
+
/* Emacs uses setjmp and longjmp for non-local exits, but
module frames cannot be skipped because they are in general
not prepared for long jumps (e.g., the behavior in C++ is undefined
passing information to the handler functions. */
/* Place this macro at the beginning of a function returning a number
- or a pointer to handle signals. The function must have an ENV
- parameter. The function will return 0 (or NULL) if a signal is
- caught. */
-#define MODULE_HANDLE_SIGNALS MODULE_HANDLE_SIGNALS_RETURN (0)
-
-/* Place this macro at the beginning of a function returning void to
- handle signals. The function must have an ENV parameter. */
-#define MODULE_HANDLE_SIGNALS_VOID MODULE_HANDLE_SIGNALS_RETURN ()
-
-#define MODULE_HANDLE_SIGNALS_RETURN(retval) \
- MODULE_SETJMP (CONDITION_CASE, module_handle_signal, retval)
-
-/* Place this macro at the beginning of a function returning a pointer
- to handle non-local exits via `throw'. The function must have an
- ENV parameter. The function will return NULL if a `throw' is
- caught. */
-#define MODULE_HANDLE_THROW \
- MODULE_SETJMP (CATCHER_ALL, module_handle_throw, NULL)
+ or a pointer to handle non-local exits. The function must have an
+ ENV parameter. The function will return the specified value if a
+ signal or throw is caught. */
+// TODO: Have Fsignal check for CATCHER_ALL so we only have to install
+// one handler.
+#define MODULE_HANDLE_NONLOCAL_EXIT(retval) \
+ MODULE_SETJMP (CONDITION_CASE, module_handle_signal, retval); \
+ MODULE_SETJMP (CATCHER_ALL, module_handle_throw, retval)
#define MODULE_SETJMP(handlertype, handlerfunc, retval) \
MODULE_SETJMP_1 (handlertype, handlerfunc, retval, \
code after the macro may longjmp back into the macro, which means
its local variable C must stay live in later code. */
+// TODO: Make backtraces work if this macros is used.
+
#define MODULE_SETJMP_1(handlertype, handlerfunc, retval, c, dummy) \
if (module_non_local_exit_check (env) != emacs_funcall_exit_return) \
return retval; \
4. Any function that needs to call Emacs facilities, such as
encoding or decoding functions, or 'intern', or 'make_string',
should protect itself from signals and 'throw' in the called
- Emacs functions, by placing the macros MODULE_HANDLE_SIGNALS
- and/or MODULE_HANDLE_THROW right after the above 2 tests.
+ Emacs functions, by placing the macro
+ MODULE_HANDLE_NONLOCAL_EXIT right after the above 2 tests.
5. Do NOT use 'eassert' for checking validity of user code in the
module. Instead, make those checks part of the code, and if the
instead of reporting the error back to Lisp, and also because
'eassert' is compiled to nothing in the release version. */
+/* Use MODULE_FUNCTION_BEGIN to implement steps 2 through 4 for most
+ environment functions. On error it will return its argument, which
+ should be a sentinel value. */
+
+#define MODULE_FUNCTION_BEGIN(error_retval) \
+ check_main_thread (); \
+ if (module_non_local_exit_check (env) != emacs_funcall_exit_return) \
+ return error_retval; \
+ MODULE_HANDLE_NONLOCAL_EXIT (error_retval)
+
/* Catch signals and throws only if the code can actually signal or
throw. If checking is enabled, abort if the current thread is not
the Emacs main thread. */
static emacs_value
module_make_global_ref (emacs_env *env, emacs_value ref)
{
- check_main_thread ();
- if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
- return NULL;
- MODULE_HANDLE_SIGNALS;
+ MODULE_FUNCTION_BEGIN (module_nil);
struct Lisp_Hash_Table *h = XHASH_TABLE (Vmodule_refs_hash);
Lisp_Object new_obj = value_to_lisp (ref);
EMACS_UINT hashcode;
if (refcount > MOST_POSITIVE_FIXNUM)
{
module_non_local_exit_signal_1 (env, Qoverflow_error, Qnil);
- return NULL;
+ return module_nil;
}
value = make_natnum (refcount);
set_hash_value_slot (h, i, value);
hash_put (h, new_obj, make_natnum (1), hashcode);
}
- return allocate_emacs_value (env, &global_storage, new_obj);
+ return lisp_to_value (new_obj);
}
static void
module_free_global_ref (emacs_env *env, emacs_value ref)
{
- check_main_thread ();
- if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
- return;
/* TODO: This probably never signals. */
/* FIXME: Wait a minute. Shouldn't this function report an error if
the hash lookup fails? */
- MODULE_HANDLE_SIGNALS_VOID;
+ MODULE_FUNCTION_BEGIN ();
struct Lisp_Hash_Table *h = XHASH_TABLE (Vmodule_refs_hash);
Lisp_Object obj = value_to_lisp (ref);
EMACS_UINT hashcode;
struct emacs_env_private *p = env->private_members;
if (p->pending_non_local_exit != emacs_funcall_exit_return)
{
- *sym = &p->non_local_exit_symbol;
- *data = &p->non_local_exit_data;
+ /* FIXME: lisp_to_value can exit non-locally. */
+ *sym = lisp_to_value (p->non_local_exit_symbol);
+ *data = lisp_to_value (p->non_local_exit_data);
}
return p->pending_non_local_exit;
}
emacs_subr subr, const char *documentation,
void *data)
{
- check_main_thread ();
- if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
- return NULL;
- MODULE_HANDLE_SIGNALS;
+ MODULE_FUNCTION_BEGIN (module_nil);
if (! (0 <= min_arity
&& (max_arity < 0
? code_convert_string_norecord (build_unibyte_string (documentation),
Qutf_8, false)
: Qnil);
+ /* FIXME: Use a bytecompiled object, or even better a subr. */
Lisp_Object ret = list4 (Qlambda,
list2 (Qand_rest, Qargs),
doc,
- list3 (Qinternal_module_call,
+ list4 (Qapply,
+ list2 (Qfunction, Qinternal_module_call),
envobj,
Qargs));
- return lisp_to_value (env, ret);
+ return lisp_to_value (ret);
}
static emacs_value
module_funcall (emacs_env *env, emacs_value fun, ptrdiff_t nargs,
emacs_value args[])
{
- check_main_thread ();
- if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
- return NULL;
- MODULE_HANDLE_SIGNALS;
- MODULE_HANDLE_THROW;
+ MODULE_FUNCTION_BEGIN (module_nil);
/* Make a new Lisp_Object array starting with the function as the
first arg, because that's what Ffuncall takes. */
newargs[0] = value_to_lisp (fun);
for (ptrdiff_t i = 0; i < nargs; i++)
newargs[1 + i] = value_to_lisp (args[i]);
- emacs_value result = lisp_to_value (env, Ffuncall (nargs + 1, newargs));
+ emacs_value result = lisp_to_value (Ffuncall (nargs + 1, newargs));
SAFE_FREE ();
return result;
}
static emacs_value
module_intern (emacs_env *env, const char *name)
{
- check_main_thread ();
- if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
- return NULL;
- MODULE_HANDLE_SIGNALS;
- return lisp_to_value (env, intern (name));
+ MODULE_FUNCTION_BEGIN (module_nil);
+ return lisp_to_value (intern (name));
}
static emacs_value
module_type_of (emacs_env *env, emacs_value value)
{
- check_main_thread ();
- if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
- return NULL;
- return lisp_to_value (env, Ftype_of (value_to_lisp (value)));
+ MODULE_FUNCTION_BEGIN (module_nil);
+ return lisp_to_value (Ftype_of (value_to_lisp (value)));
}
static bool
static intmax_t
module_extract_integer (emacs_env *env, emacs_value n)
{
- check_main_thread ();
- if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
- return 0;
+ MODULE_FUNCTION_BEGIN (0);
Lisp_Object l = value_to_lisp (n);
if (! INTEGERP (l))
{
static emacs_value
module_make_integer (emacs_env *env, intmax_t n)
{
- check_main_thread ();
- if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
- return NULL;
+ MODULE_FUNCTION_BEGIN (module_nil);
if (! (MOST_NEGATIVE_FIXNUM <= n && n <= MOST_POSITIVE_FIXNUM))
{
module_non_local_exit_signal_1 (env, Qoverflow_error, Qnil);
- return NULL;
+ return module_nil;
}
- return lisp_to_value (env, make_number (n));
+ return lisp_to_value (make_number (n));
}
static double
module_extract_float (emacs_env *env, emacs_value f)
{
- check_main_thread ();
- if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
- return 0;
+ MODULE_FUNCTION_BEGIN (0);
Lisp_Object lisp = value_to_lisp (f);
if (! FLOATP (lisp))
{
static emacs_value
module_make_float (emacs_env *env, double d)
{
- check_main_thread ();
- if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
- return NULL;
- MODULE_HANDLE_SIGNALS;
- return lisp_to_value (env, make_float (d));
+ MODULE_FUNCTION_BEGIN (module_nil);
+ return lisp_to_value (make_float (d));
}
static bool
module_copy_string_contents (emacs_env *env, emacs_value value, char *buffer,
ptrdiff_t *length)
{
- check_main_thread ();
- if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
- return false;
- MODULE_HANDLE_SIGNALS;
+ MODULE_FUNCTION_BEGIN (false);
Lisp_Object lisp_str = value_to_lisp (value);
if (! STRINGP (lisp_str))
{
static emacs_value
module_make_string (emacs_env *env, const char *str, ptrdiff_t length)
{
- check_main_thread ();
- if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
- return NULL;
- MODULE_HANDLE_SIGNALS;
+ MODULE_FUNCTION_BEGIN (module_nil);
if (length > STRING_BYTES_BOUND)
{
module_non_local_exit_signal_1 (env, Qoverflow_error, Qnil);
- return NULL;
+ return module_nil;
}
Lisp_Object lstr = make_unibyte_string (str, length);
- return lisp_to_value (env,
- code_convert_string_norecord (lstr, Qutf_8, false));
+ return lisp_to_value (code_convert_string_norecord (lstr, Qutf_8, false));
}
static emacs_value
module_make_user_ptr (emacs_env *env, emacs_finalizer_function fin, void *ptr)
{
- check_main_thread ();
- if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
- return NULL;
- return lisp_to_value (env, make_user_ptr (fin, ptr));
+ MODULE_FUNCTION_BEGIN (module_nil);
+ return lisp_to_value (make_user_ptr (fin, ptr));
}
static void *
module_get_user_ptr (emacs_env *env, emacs_value uptr)
{
- check_main_thread ();
- if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
- return NULL;
+ MODULE_FUNCTION_BEGIN (NULL);
Lisp_Object lisp = value_to_lisp (uptr);
if (! USER_PTRP (lisp))
{
static void
module_set_user_ptr (emacs_env *env, emacs_value uptr, void *ptr)
{
+ /* FIXME: This function should return bool because it can fail. */
+ MODULE_FUNCTION_BEGIN ();
check_main_thread ();
if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
return;
static emacs_finalizer_function
module_get_user_finalizer (emacs_env *env, emacs_value uptr)
{
- check_main_thread ();
- if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
- return NULL;
+ MODULE_FUNCTION_BEGIN (NULL);
Lisp_Object lisp = value_to_lisp (uptr);
if (! USER_PTRP (lisp))
{
module_set_user_finalizer (emacs_env *env, emacs_value uptr,
emacs_finalizer_function fin)
{
- check_main_thread ();
- if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
- return;
+ /* FIXME: This function should return bool because it can fail. */
+ MODULE_FUNCTION_BEGIN ();
Lisp_Object lisp = value_to_lisp (uptr);
if (! USER_PTRP (lisp))
module_wrong_type (env, Quser_ptr, lisp);
static void
module_vec_set (emacs_env *env, emacs_value vec, ptrdiff_t i, emacs_value val)
{
- check_main_thread ();
- if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
- return;
+ /* FIXME: This function should return bool because it can fail. */
+ MODULE_FUNCTION_BEGIN ();
Lisp_Object lvec = value_to_lisp (vec);
if (! VECTORP (lvec))
{
static emacs_value
module_vec_get (emacs_env *env, emacs_value vec, ptrdiff_t i)
{
- check_main_thread ();
- if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
- return NULL;
+ MODULE_FUNCTION_BEGIN (module_nil);
Lisp_Object lvec = value_to_lisp (vec);
if (! VECTORP (lvec))
{
module_wrong_type (env, Qvectorp, lvec);
- return NULL;
+ return module_nil;
}
if (! (0 <= i && i < ASIZE (lvec)))
{
module_args_out_of_range (env, lvec, make_number (i));
else
module_non_local_exit_signal_1 (env, Qoverflow_error, Qnil);
- return NULL;
+ return module_nil;
}
- return lisp_to_value (env, AREF (lvec, i));
+ return lisp_to_value (AREF (lvec, i));
}
static ptrdiff_t
module_vec_size (emacs_env *env, emacs_value vec)
{
- check_main_thread ();
- if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
- return 0;
+ /* FIXME: Return a sentinel value (e.g., -1) on error. */
+ MODULE_FUNCTION_BEGIN (0);
Lisp_Object lvec = value_to_lisp (vec);
if (! VECTORP (lvec))
{
return Qt;
}
-DEFUN ("internal--module-call", Finternal_module_call, Sinternal_module_call, 2, 2, 0,
+DEFUN ("internal--module-call", Finternal_module_call, Sinternal_module_call, 1, MANY, 0,
doc: /* Internal function to call a module function.
ENVOBJ is a save pointer to a module_fun_env structure.
-ARGLIST is a list of arguments passed to SUBRPTR. */)
- (Lisp_Object envobj, Lisp_Object arglist)
+ARGLIST is a list of arguments passed to SUBRPTR.
+usage: (module-call ENVOBJ &rest ARGLIST) */)
+ (ptrdiff_t nargs, Lisp_Object *arglist)
{
+ Lisp_Object envobj = arglist[0];
+ /* FIXME: Rather than use a save_value, we should create a new object type.
+ Making save_value visible to Lisp is wrong. */
CHECK_TYPE (SAVE_VALUEP (envobj), Qsave_value_p, envobj);
struct Lisp_Save_Value *save_value = XSAVE_VALUE (envobj);
CHECK_TYPE (save_type (save_value, 0) == SAVE_POINTER, Qsave_pointer_p, envobj);
- CHECK_CONS (arglist);
+ /* FIXME: We have no reason to believe that XSAVE_POINTER (envobj, 0)
+ is a module_fun_env pointer. If some other part of Emacs also
+ exports save_value objects to Elisp, than we may be getting here this
+ other kind of save_value which will likely hold something completely
+ different in this field. */
struct module_fun_env *envptr = XSAVE_POINTER (envobj, 0);
- EMACS_INT len = XFASTINT (Flength (arglist));
+ EMACS_INT len = nargs - 1;
eassume (0 <= envptr->min_arity);
if (! (envptr->min_arity <= len
&& len <= (envptr->max_arity < 0 ? PTRDIFF_MAX : envptr->max_arity)))
struct emacs_env_private priv;
initialize_environment (&pub, &priv);
- emacs_value *args = xnmalloc (len, sizeof *args);
-
- for (ptrdiff_t i = 0; i < len; i++)
+ USE_SAFE_ALLOCA;
+ emacs_value *args;
+ if (plain_values)
+ args = (emacs_value *) arglist + 1;
+ else
{
- args[i] = lisp_to_value (&pub, XCAR (arglist));
- if (! args[i])
- memory_full (sizeof *args[i]);
- arglist = XCDR (arglist);
+ args = SAFE_ALLOCA (len * sizeof *args);
+ for (ptrdiff_t i = 0; i < len; i++)
+ args[i] = lisp_to_value (arglist[i + 1]);
}
emacs_value ret = envptr->subr (&pub, len, args, envptr->data);
- xfree (args);
+ SAFE_FREE ();
eassert (&priv == pub.private_members);
{
case emacs_funcall_exit_return:
finalize_environment (&priv);
- if (ret == NULL)
- xsignal1 (Qinvalid_module_call, module_format_fun_env (envptr));
return value_to_lisp (ret);
case emacs_funcall_exit_signal:
{
- Lisp_Object symbol = value_to_lisp (&priv.non_local_exit_symbol);
- Lisp_Object data = value_to_lisp (&priv.non_local_exit_data);
+ Lisp_Object symbol = priv.non_local_exit_symbol;
+ Lisp_Object data = priv.non_local_exit_data;
finalize_environment (&priv);
xsignal (symbol, data);
}
case emacs_funcall_exit_throw:
{
- Lisp_Object tag = value_to_lisp (&priv.non_local_exit_symbol);
- Lisp_Object value = value_to_lisp (&priv.non_local_exit_data);
+ Lisp_Object tag = priv.non_local_exit_symbol;
+ Lisp_Object value = priv.non_local_exit_data;
finalize_environment (&priv);
Fthrow (tag, value);
}
static void
check_main_thread (void)
{
-#ifdef HAVE_THREADS_H
- eassert (thrd_equal (thdr_current (), main_thread));
-#elif defined HAVE_PTHREAD
+#ifdef HAVE_PTHREAD
eassert (pthread_equal (pthread_self (), main_thread));
#elif defined WINDOWSNT
eassert (GetCurrentThreadId () == main_thread);
if (p->pending_non_local_exit == emacs_funcall_exit_return)
{
p->pending_non_local_exit = emacs_funcall_exit_signal;
- p->non_local_exit_symbol.v = sym;
- p->non_local_exit_data.v = data;
+ p->non_local_exit_symbol = sym;
+ p->non_local_exit_data = data;
}
}
if (p->pending_non_local_exit == emacs_funcall_exit_return)
{
p->pending_non_local_exit = emacs_funcall_exit_throw;
- p->non_local_exit_symbol.v = tag;
- p->non_local_exit_data.v = value;
+ p->non_local_exit_symbol = tag;
+ p->non_local_exit_data = value;
}
}
\f
/* Value conversion. */
-/* Convert an `emacs_value' to the corresponding internal object.
- Never fails. */
+/* Unique Lisp_Object used to mark those emacs_values which are really
+ just containers holding a Lisp_Object that does not fit as an emacs_value,
+ either because it is an integer out of range, or is not properly aligned.
+ Used only if !plain_values. */
+static Lisp_Object ltv_mark;
+
+/* Convert V to the corresponding internal object O, such that
+ V == lisp_to_value_bits (O). Never fails. */
static Lisp_Object
-value_to_lisp (emacs_value v)
+value_to_lisp_bits (emacs_value v)
{
- return v->v;
-}
+ intptr_t i = (intptr_t) v;
+ if (plain_values || USE_LSB_TAG)
+ return XIL (i);
+
+ /* With wide EMACS_INT and when tag bits are the most significant,
+ reassembling integers differs from reassembling pointers in two
+ ways. First, save and restore the least-significant bits of the
+ integer, not the most-significant bits. Second, sign-extend the
+ integer when restoring, but zero-extend pointers because that
+ makes TAG_PTR faster. */
+
+ EMACS_UINT tag = i & (GCALIGNMENT - 1);
+ EMACS_UINT untagged = i - tag;
+ switch (tag)
+ {
+ case_Lisp_Int:
+ {
+ bool negative = tag & 1;
+ EMACS_UINT sign_extension
+ = negative ? VALMASK & ~(INTPTR_MAX >> INTTYPEBITS): 0;
+ uintptr_t u = i;
+ intptr_t all_but_sign = u >> GCTYPEBITS;
+ untagged = sign_extension + all_but_sign;
+ break;
+ }
+ }
-/* Convert an internal object to an `emacs_value'. Allocate storage
- from the environment; return NULL if allocation fails. */
-static emacs_value
-lisp_to_value (emacs_env *env, Lisp_Object o)
-{
- struct emacs_env_private *p = env->private_members;
- if (p->pending_non_local_exit != emacs_funcall_exit_return)
- return NULL;
- return allocate_emacs_value (env, &p->storage, o);
+ return XIL ((tag << VALBITS) + untagged);
}
-\f
-/* Memory management. */
-
-/* Must be called for each frame before it can be used for allocation. */
-static void
-initialize_frame (struct emacs_value_frame *frame)
+/* If V was computed from lisp_to_value (O), then return O.
+ Exits non-locally only if the stack overflows. */
+static Lisp_Object
+value_to_lisp (emacs_value v)
{
- frame->offset = 0;
- frame->next = NULL;
+ Lisp_Object o = value_to_lisp_bits (v);
+ if (! plain_values && CONSP (o) && EQ (XCDR (o), ltv_mark))
+ o = XCAR (o);
+ return o;
}
-/* Must be called for any storage object before it can be used for
- allocation. */
-static void
-initialize_storage (struct emacs_value_storage *storage)
+/* Attempt to convert O to an emacs_value. Do not do any checking or
+ or allocate any storage; the caller should prevent or detect
+ any resulting bit pattern that is not a valid emacs_value. */
+static emacs_value
+lisp_to_value_bits (Lisp_Object o)
{
- initialize_frame (&storage->initial);
- storage->current = &storage->initial;
-}
+ EMACS_UINT u = XLI (o);
-/* Must be called for any initialized storage object before its
- lifetime ends. Free all dynamically-allocated frames. */
-static void
-finalize_storage (struct emacs_value_storage *storage)
-{
- struct emacs_value_frame *next = storage->initial.next;
- while (next != NULL)
- {
- struct emacs_value_frame *current = next;
- next = current->next;
- free (current);
- }
+ /* Compress U into the space of a pointer, possibly losing information. */
+ uintptr_t p = (plain_values || USE_LSB_TAG
+ ? u
+ : (INTEGERP (o) ? u << VALBITS : u & VALMASK) + XTYPE (o));
+ return (emacs_value) p;
}
-/* Allocate a new value from STORAGE and stores OBJ in it. Return
- NULL if allocation fails and use ENV for non local exit reporting. */
+#ifndef HAVE_STRUCT_ATTRIBUTE_ALIGNED
+enum { HAVE_STRUCT_ATTRIBUTE_ALIGNED = 0 };
+#endif
+
+/* Convert O to an emacs_value. Allocate storage if needed; this can
+ signal if memory is exhausted. Must be an injective function. */
static emacs_value
-allocate_emacs_value (emacs_env *env, struct emacs_value_storage *storage,
- Lisp_Object obj)
+lisp_to_value (Lisp_Object o)
{
- eassert (storage->current);
- eassert (storage->current->offset < value_frame_size);
- eassert (! storage->current->next);
- if (storage->current->offset == value_frame_size - 1)
- {
- storage->current->next = malloc (sizeof *storage->current->next);
- if (! storage->current->next)
- {
- module_out_of_memory (env);
- return NULL;
- }
- initialize_frame (storage->current->next);
- storage->current = storage->current->next;
- }
- emacs_value value = storage->current->objects + storage->current->offset;
- value->v = obj;
- ++storage->current->offset;
- return value;
-}
+ emacs_value v = lisp_to_value_bits (o);
-/* Mark all objects allocated from local environments so that they
- don't get garbage-collected. */
-void
-mark_modules (void)
-{
- for (Lisp_Object tem = Vmodule_environments; CONSP (tem); tem = XCDR (tem))
+ if (! EQ (o, value_to_lisp_bits (v)))
{
- struct emacs_env_private *priv = XSAVE_POINTER (tem, 0);
- for (struct emacs_value_frame *frame = &priv->storage.initial;
- frame != NULL;
- frame = frame->next)
- for (int i = 0; i < frame->offset; ++i)
- mark_object (frame->objects[i].v);
+ /* Package the incompressible object pointer inside a pair
+ that is compressible. */
+ Lisp_Object pair = Fcons (o, ltv_mark);
+
+ if (! HAVE_STRUCT_ATTRIBUTE_ALIGNED)
+ {
+ /* Keep calling Fcons until it returns a compressible pair.
+ This shouldn't take long. */
+ while ((intptr_t) XCONS (pair) & (GCALIGNMENT - 1))
+ pair = Fcons (o, pair);
+
+ /* Plant the mark. The garbage collector will eventually
+ reclaim any just-allocated incompressible pairs. */
+ XSETCDR (pair, ltv_mark);
+ }
+
+ v = (emacs_value) ((intptr_t) XCONS (pair) + Lisp_Cons);
}
+
+ eassert (EQ (o, value_to_lisp (v)));
+ return v;
}
\f
initialize_environment (emacs_env *env, struct emacs_env_private *priv)
{
priv->pending_non_local_exit = emacs_funcall_exit_return;
- initialize_storage (&priv->storage);
env->size = sizeof *env;
env->private_members = priv;
env->make_global_ref = module_make_global_ref;
env->vec_set = module_vec_set;
env->vec_get = module_vec_get;
env->vec_size = module_vec_size;
- Vmodule_environments = Fcons (make_save_ptr (priv), Vmodule_environments);
+ Vmodule_environments = Fcons (make_save_ptr (env), Vmodule_environments);
}
/* Must be called before the lifetime of the environment object
static void
finalize_environment (struct emacs_env_private *env)
{
- finalize_storage (&env->storage);
Vmodule_environments = XCDR (Vmodule_environments);
}
void
syms_of_module (void)
{
+ if (!plain_values)
+ ltv_mark = Fcons (Qnil, Qnil);
+ eassert (NILP (value_to_lisp (module_nil)));
+
DEFSYM (Qmodule_refs_hash, "module-refs-hash");
DEFVAR_LISP ("module-refs-hash", Vmodule_refs_hash,
- doc: /* Module global referrence table. */);
+ doc: /* Module global reference table. */);
Vmodule_refs_hash
= make_hash_table (hashtest_eq, make_number (DEFAULT_HASH_SIZE),
Fput (Qinvalid_arity, Qerror_message,
build_pure_c_string ("Invalid function arity"));
- initialize_storage (&global_storage);
-
/* Unintern `module-refs-hash' because it is internal-only and Lisp
code or modules should not access it. */
Funintern (Qmodule_refs_hash, Qnil);
{
/* It is not guaranteed that dynamic initializers run in the main thread,
therefore detect the main thread here. */
-#ifdef HAVE_THREADS_H
- main_thread = thrd_current ();
-#elif defined HAVE_PTHREAD
+#ifdef HAVE_PTHREAD
main_thread = pthread_self ();
#elif defined WINDOWSNT
/* The 'main' function already recorded the main thread's thread ID,