#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
+#include <stdlib.h>
#include "lisp.h"
#include "dynlib.h"
#include "w32term.h"
#endif
-/* 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 the module init function. */
typedef int (*emacs_init_function) (struct emacs_runtime *);
in this module, though, so this constraint is not enforced here. */
typedef void (*emacs_finalizer_function) (void *);
+\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;
+
\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. */
- Lisp_Object non_local_exit_symbol, non_local_exit_data;
+ struct emacs_value_tag non_local_exit_symbol, non_local_exit_data;
- /* List of values allocated from this environment. The code uses
- this only if the user gave the -module-assertions command-line
- option. */
- Lisp_Object values;
+ struct emacs_value_storage storage;
};
/* The private parts of an `emacs_runtime' object contain the initial
/* Forward declarations. */
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 enum emacs_funcall_exit module_non_local_exit_check (emacs_env *);
static void module_assert_thread (void);
static void module_out_of_memory (emacs_env *);
static void module_reset_handlerlist (struct handler **);
-/* 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;
-
static bool module_assertions = false;
-static emacs_env *global_env;
-static struct emacs_env_private global_env_private;
\f
/* Convenience macros for non-local exit handling. */
static emacs_value
module_make_global_ref (emacs_env *env, emacs_value ref)
{
- MODULE_FUNCTION_BEGIN (module_nil);
+ MODULE_FUNCTION_BEGIN (NULL);
struct Lisp_Hash_Table *h = XHASH_TABLE (Vmodule_refs_hash);
Lisp_Object new_obj = value_to_lisp (ref);
EMACS_UINT hashcode;
hash_put (h, new_obj, make_fixed_natnum (1), hashcode);
}
- return lisp_to_value (module_assertions ? global_env : env, new_obj);
+ return allocate_emacs_value (env, &global_storage, new_obj);
}
static void
if (module_assertions)
{
- Lisp_Object globals = global_env_private.values;
- Lisp_Object prev = Qnil;
ptrdiff_t count = 0;
- for (Lisp_Object tail = globals; CONSP (tail);
- tail = XCDR (tail))
+ for (struct emacs_value_frame *frame = &global_storage.initial;
+ frame != NULL; frame = frame->next)
{
- emacs_value global = xmint_pointer (XCAR (tail));
- if (global == ref)
+ for (int i = 0; i < frame->offset; ++i)
{
- if (NILP (prev))
- global_env_private.values = XCDR (globals);
- else
- XSETCDR (prev, XCDR (tail));
- return;
+ if (&frame->objects[i] == ref)
+ return;
+ ++count;
}
- ++count;
- prev = tail;
}
module_abort ("Global value was not found in list of %"pD"d globals",
count);
struct emacs_env_private *p = env->private_members;
if (p->pending_non_local_exit != emacs_funcall_exit_return)
{
- /* FIXME: lisp_to_value can exit non-locally. */
- *sym = lisp_to_value (env, p->non_local_exit_symbol);
- *data = lisp_to_value (env, p->non_local_exit_data);
+ *sym = &p->non_local_exit_symbol;
+ *data = &p->non_local_exit_data;
}
return p->pending_non_local_exit;
}
emacs_subr subr, const char *documentation,
void *data)
{
- MODULE_FUNCTION_BEGIN (module_nil);
+ MODULE_FUNCTION_BEGIN (NULL);
if (! (0 <= min_arity
&& (max_arity < 0
module_funcall (emacs_env *env, emacs_value fun, ptrdiff_t nargs,
emacs_value args[])
{
- MODULE_FUNCTION_BEGIN (module_nil);
+ MODULE_FUNCTION_BEGIN (NULL);
/* Make a new Lisp_Object array starting with the function as the
first arg, because that's what Ffuncall takes. */
static emacs_value
module_intern (emacs_env *env, const char *name)
{
- MODULE_FUNCTION_BEGIN (module_nil);
+ MODULE_FUNCTION_BEGIN (NULL);
return lisp_to_value (env, intern (name));
}
static emacs_value
module_type_of (emacs_env *env, emacs_value value)
{
- MODULE_FUNCTION_BEGIN (module_nil);
+ MODULE_FUNCTION_BEGIN (NULL);
return lisp_to_value (env, Ftype_of (value_to_lisp (value)));
}
static emacs_value
module_make_integer (emacs_env *env, intmax_t n)
{
- MODULE_FUNCTION_BEGIN (module_nil);
+ MODULE_FUNCTION_BEGIN (NULL);
return lisp_to_value (env, make_int (n));
}
static emacs_value
module_make_float (emacs_env *env, double d)
{
- MODULE_FUNCTION_BEGIN (module_nil);
+ MODULE_FUNCTION_BEGIN (NULL);
return lisp_to_value (env, make_float (d));
}
static emacs_value
module_make_string (emacs_env *env, const char *str, ptrdiff_t length)
{
- MODULE_FUNCTION_BEGIN (module_nil);
+ MODULE_FUNCTION_BEGIN (NULL);
if (! (0 <= length && length <= STRING_BYTES_BOUND))
overflow_error ();
/* FIXME: AUTO_STRING_WITH_LEN requires STR to be NUL-terminated,
static emacs_value
module_make_user_ptr (emacs_env *env, emacs_finalizer_function fin, void *ptr)
{
- MODULE_FUNCTION_BEGIN (module_nil);
+ MODULE_FUNCTION_BEGIN (NULL);
return lisp_to_value (env, make_user_ptr (fin, ptr));
}
static emacs_value
module_vec_get (emacs_env *env, emacs_value vec, ptrdiff_t i)
{
- MODULE_FUNCTION_BEGIN (module_nil);
+ MODULE_FUNCTION_BEGIN (NULL);
Lisp_Object lvec = value_to_lisp (vec);
check_vec_index (lvec, i);
return lisp_to_value (env, AREF (lvec, i));
case emacs_funcall_exit_return:
return;
case emacs_funcall_exit_signal:
- xsignal (env->non_local_exit_symbol, env->non_local_exit_data);
+ xsignal (value_to_lisp (&env->non_local_exit_symbol),
+ value_to_lisp (&env->non_local_exit_data));
case emacs_funcall_exit_throw:
- Fthrow (env->non_local_exit_symbol, env->non_local_exit_data);
+ Fthrow (value_to_lisp (&env->non_local_exit_symbol),
+ value_to_lisp (&env->non_local_exit_data));
default:
eassume (false);
}
record_unwind_protect_ptr (finalize_environment_unwind, env);
USE_SAFE_ALLOCA;
- ATTRIBUTE_MAY_ALIAS emacs_value *args;
- if (plain_values && ! module_assertions)
- /* FIXME: The cast below is incorrect because the argument array
- is not declared as const, so module functions can modify it.
- Either declare it as const, or remove this branch. */
- args = (emacs_value *) arglist;
- else
+ emacs_value *args = nargs > 0 ? SAFE_ALLOCA (nargs * sizeof *args) : NULL;
+ for (ptrdiff_t i = 0; i < nargs; ++i)
{
- args = SAFE_ALLOCA (nargs * sizeof *args);
- for (ptrdiff_t i = 0; i < nargs; i++)
- args[i] = lisp_to_value (env, arglist[i]);
+ args[i] = lisp_to_value (env, arglist[i]);
+ if (! args[i])
+ memory_full (sizeof *args[i]);
}
emacs_value ret = func->subr (env, nargs, args, func->data);
if (p->pending_non_local_exit == emacs_funcall_exit_return)
{
p->pending_non_local_exit = emacs_funcall_exit_signal;
- p->non_local_exit_symbol = sym;
- p->non_local_exit_data = data;
+ p->non_local_exit_symbol.v = sym;
+ p->non_local_exit_data.v = 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 = tag;
- p->non_local_exit_data = value;
+ p->non_local_exit_symbol.v = tag;
+ p->non_local_exit_data.v = value;
}
}
\f
/* Value conversion. */
-/* We represent Lisp objects differently depending on whether the user
- gave -module-assertions. If assertions are disabled, emacs_value
- objects are Lisp_Objects cast to emacs_value. If assertions are
- enabled, emacs_value objects are pointers to Lisp_Object objects
- allocated from the free store; they are never freed, which ensures
- that their addresses are unique and can be used for liveness
- checking. */
-
-/* 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_bits (emacs_value v)
-{
- if (plain_values || USE_LSB_TAG)
- return XPL (v);
-
- /* 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. */
-
- intptr_t i = (intptr_t) v;
- EMACS_UINT tag = i & ((1 << GCTYPEBITS) - 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;
- }
- }
-
- return XIL ((tag << VALBITS) + untagged);
-}
+/* Convert an `emacs_value' to the corresponding internal object.
+ Never fails. */
/* If V was computed from lisp_to_value (O), then return O.
Exits non-locally only if the stack overflows. */
{
/* Check the liveness of the value by iterating over all live
environments. */
- void *vptr = v;
- ATTRIBUTE_MAY_ALIAS Lisp_Object *optr = vptr;
ptrdiff_t num_environments = 0;
ptrdiff_t num_values = 0;
for (Lisp_Object environments = Vmodule_environments;
CONSP (environments); environments = XCDR (environments))
{
emacs_env *env = xmint_pointer (XCAR (environments));
- for (Lisp_Object values = env->private_members->values;
- CONSP (values); values = XCDR (values))
+ struct emacs_env_private *priv = env->private_members;
+ /* The value might be one of the nonlocal exit values. Note
+ that we don't check whether a nonlocal exit is currently
+ pending, because the module might have cleared the flag
+ in the meantime. */
+ if (&priv->non_local_exit_symbol == v
+ || &priv->non_local_exit_data == v)
+ goto ok;
+ for (struct emacs_value_frame *frame = &priv->storage.initial;
+ frame != NULL; frame = frame->next)
{
- Lisp_Object *p = xmint_pointer (XCAR (values));
- if (p == optr)
- return *p;
- ++num_values;
+ for (int i = 0; i < frame->offset; ++i)
+ {
+ if (&frame->objects[i] == v)
+ goto ok;
+ ++num_values;
+ }
}
++num_environments;
}
+ /* Also check global values. */
+ for (struct emacs_value_frame *frame = &global_storage.initial;
+ frame != NULL; frame = frame->next)
+ {
+ for (int i = 0; i < frame->offset; ++i)
+ {
+ if (&frame->objects[i] == v)
+ goto ok;
+ ++num_values;
+ }
+ }
module_abort (("Emacs value not found in %"pD"d values "
"of %"pD"d environments"),
num_values, num_environments);
}
- Lisp_Object o = value_to_lisp_bits (v);
- if (! plain_values && CONSP (o) && EQ (XCDR (o), ltv_mark))
- o = XCAR (o);
- return o;
+ ok: return v->v;
}
-/* Attempt to convert O to an emacs_value. Do not do any checking
- or allocate any storage; the caller should prevent or detect
- any resulting bit pattern that is not a valid emacs_value. */
+/* Convert an internal object to an `emacs_value'. Allocate storage
+ from the environment; return NULL if allocation fails. */
static emacs_value
-lisp_to_value_bits (Lisp_Object o)
+lisp_to_value (emacs_env *env, Lisp_Object o)
{
- if (plain_values || USE_LSB_TAG)
- return XLP (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);
+}
- /* Compress O into the space of a pointer, possibly losing information. */
- EMACS_UINT u = XLI (o);
- if (FIXNUMP (o))
- {
- uintptr_t i = (u << VALBITS) + XTYPE (o);
- return (emacs_value) i;
- }
- else
+/* Must be called for each frame before it can be used for allocation. */
+static void
+initialize_frame (struct emacs_value_frame *frame)
+{
+ frame->offset = 0;
+ frame->next = NULL;
+}
+
+/* Must be called for any storage object before it can be used for
+ allocation. */
+static void
+initialize_storage (struct emacs_value_storage *storage)
+{
+ initialize_frame (&storage->initial);
+ storage->current = &storage->initial;
+}
+
+/* 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)
{
- char *p = XLP (o);
- void *v = p - (u & ~VALMASK) + XTYPE (o);
- return v;
+ struct emacs_value_frame *current = next;
+ next = current->next;
+ free (current);
}
}
-/* Convert O to an emacs_value. Allocate storage if needed; this can
- signal if memory is exhausted. Must be an injective function. */
+/* Allocate a new value from STORAGE and stores OBJ in it. Return
+ NULL if allocation fails and use ENV for non local exit reporting. */
static emacs_value
-lisp_to_value (emacs_env *env, Lisp_Object o)
+allocate_emacs_value (emacs_env *env, struct emacs_value_storage *storage,
+ Lisp_Object obj)
{
- if (module_assertions)
+ eassert (storage->current);
+ eassert (storage->current->offset < value_frame_size);
+ eassert (! storage->current->next);
+ if (storage->current->offset == value_frame_size - 1)
{
- /* Add the new value to the list of values allocated from this
- environment. The value is actually a pointer to the
- Lisp_Object cast to emacs_value. We make a copy of the
- object on the free store to guarantee unique addresses. */
- ATTRIBUTE_MAY_ALIAS Lisp_Object *optr = xmalloc (sizeof o);
- *optr = o;
- void *vptr = optr;
- ATTRIBUTE_MAY_ALIAS emacs_value ret = vptr;
- struct emacs_env_private *priv = env->private_members;
- priv->values = Fcons (make_mint_ptr (ret), priv->values);
- return ret;
+ 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);
-
- if (! EQ (o, value_to_lisp_bits (v)))
+/* 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))
{
- /* Package the incompressible object pointer inside a pair
- that is compressible. */
- Lisp_Object pair = Fcons (o, ltv_mark);
- v = (emacs_value) ((intptr_t) XCONS (pair) + Lisp_Cons);
+ emacs_env *env = xmint_pointer (XCAR (tem));
+ struct emacs_env_private *priv = env->private_members;
+ 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);
}
-
- eassert (EQ (o, value_to_lisp (v)));
- return v;
}
\f
env = xmalloc (sizeof *env);
priv->pending_non_local_exit = emacs_funcall_exit_return;
- priv->values = priv->non_local_exit_symbol = priv->non_local_exit_data = Qnil;
+ initialize_storage (&priv->storage);
env->size = sizeof *env;
env->private_members = priv;
env->make_global_ref = module_make_global_ref;
static void
finalize_environment (emacs_env *env)
{
+ finalize_storage (&env->private_members->storage);
eassert (xmint_pointer (XCAR (Vmodule_environments)) == env);
Vmodule_environments = XCDR (Vmodule_environments);
- if (module_assertions)
- /* There is always at least the global environment. */
- eassert (CONSP (Vmodule_environments));
}
static void
finalize_environment (ert->private_members->env);
}
-void
-mark_modules (void)
-{
- for (Lisp_Object tail = Vmodule_environments; CONSP (tail);
- tail = XCDR (tail))
- {
- emacs_env *env = xmint_pointer (XCAR (tail));
- struct emacs_env_private *priv = env->private_members;
- mark_object (priv->non_local_exit_symbol);
- mark_object (priv->non_local_exit_data);
- mark_object (priv->values);
- }
-}
-
\f
/* Non-local exit handling. */
/* If enabling module assertions, use a hidden environment for
storing the globals. This environment is never freed. */
module_assertions = enable;
- if (enable)
- global_env = initialize_environment (NULL, &global_env_private);
+ initialize_storage (&global_storage);
}
static _Noreturn void
void
syms_of_module (void)
{
- if (!plain_values)
- {
- ltv_mark = Fcons (Qnil, Qnil);
- staticpro (<v_mark);
- }
- 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 reference table. */);
projects / emacs.git / commitdiff