#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. */
- struct emacs_value_tag non_local_exit_symbol, non_local_exit_data;
+ Lisp_Object non_local_exit_symbol, non_local_exit_data;
- struct emacs_value_storage storage;
+ /* 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;
};
/* 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 (NULL);
+ 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;
hash_put (h, new_obj, make_fixed_natnum (1), hashcode);
}
- return allocate_emacs_value (env, &global_storage, new_obj);
+ return lisp_to_value (module_assertions ? global_env : env, new_obj);
}
static void
if (module_assertions)
{
+ Lisp_Object globals = global_env_private.values;
+ Lisp_Object prev = Qnil;
ptrdiff_t count = 0;
- for (struct emacs_value_frame *frame = &global_storage.initial;
- frame != NULL; frame = frame->next)
+ for (Lisp_Object tail = globals; CONSP (tail);
+ tail = XCDR (tail))
{
- for (int i = 0; i < frame->offset; ++i)
+ emacs_value global = xmint_pointer (XCAR (tail));
+ if (global == ref)
{
- if (&frame->objects[i] == ref)
- return;
- ++count;
+ if (NILP (prev))
+ global_env_private.values = XCDR (globals);
+ else
+ XSETCDR (prev, XCDR (tail));
+ return;
}
+ ++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)
{
- *sym = &p->non_local_exit_symbol;
- *data = &p->non_local_exit_data;
+ /* 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);
}
return p->pending_non_local_exit;
}
emacs_subr subr, const char *documentation,
void *data)
{
- MODULE_FUNCTION_BEGIN (NULL);
+ MODULE_FUNCTION_BEGIN (module_nil);
if (! (0 <= min_arity
&& (max_arity < 0
module_funcall (emacs_env *env, emacs_value fun, ptrdiff_t nargs,
emacs_value args[])
{
- MODULE_FUNCTION_BEGIN (NULL);
+ 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. */
static emacs_value
module_intern (emacs_env *env, const char *name)
{
- MODULE_FUNCTION_BEGIN (NULL);
+ MODULE_FUNCTION_BEGIN (module_nil);
return lisp_to_value (env, intern (name));
}
static emacs_value
module_type_of (emacs_env *env, emacs_value value)
{
- MODULE_FUNCTION_BEGIN (NULL);
+ MODULE_FUNCTION_BEGIN (module_nil);
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 (NULL);
+ MODULE_FUNCTION_BEGIN (module_nil);
return lisp_to_value (env, make_int (n));
}
static emacs_value
module_make_float (emacs_env *env, double d)
{
- MODULE_FUNCTION_BEGIN (NULL);
+ MODULE_FUNCTION_BEGIN (module_nil);
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 (NULL);
+ MODULE_FUNCTION_BEGIN (module_nil);
if (! (0 <= length && length <= STRING_BYTES_BOUND))
overflow_error ();
/* FIXME: AUTO_STRING_WITH_LEN requires STR to be null-terminated,
static emacs_value
module_make_user_ptr (emacs_env *env, emacs_finalizer_function fin, void *ptr)
{
- MODULE_FUNCTION_BEGIN (NULL);
+ MODULE_FUNCTION_BEGIN (module_nil);
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 (NULL);
+ MODULE_FUNCTION_BEGIN (module_nil);
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 (value_to_lisp (&env->non_local_exit_symbol),
- value_to_lisp (&env->non_local_exit_data));
+ xsignal (env->non_local_exit_symbol, env->non_local_exit_data);
case emacs_funcall_exit_throw:
- Fthrow (value_to_lisp (&env->non_local_exit_symbol),
- value_to_lisp (&env->non_local_exit_data));
+ Fthrow (env->non_local_exit_symbol, env->non_local_exit_data);
default:
eassume (false);
}
record_unwind_protect_ptr (finalize_environment_unwind, env);
USE_SAFE_ALLOCA;
- emacs_value *args = nargs > 0 ? SAFE_ALLOCA (nargs * sizeof *args) : NULL;
- for (ptrdiff_t i = 0; i < nargs; ++i)
+ 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
{
- args[i] = lisp_to_value (env, arglist[i]);
- if (! args[i])
- memory_full (sizeof *args[i]);
+ args = SAFE_ALLOCA (nargs * sizeof *args);
+ for (ptrdiff_t i = 0; i < nargs; i++)
+ args[i] = lisp_to_value (env, arglist[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.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. */
+/* 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);
+}
/* 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));
- 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)
+ for (Lisp_Object values = env->private_members->values;
+ CONSP (values); values = XCDR (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;
+ Lisp_Object *p = xmint_pointer (XCAR (values));
+ if (p == optr)
+ return *p;
++num_values;
}
+ ++num_environments;
}
module_abort (("Emacs value not found in %"pD"d values "
"of %"pD"d environments"),
num_values, num_environments);
}
- ok: return v->v;
+ Lisp_Object o = value_to_lisp_bits (v);
+ if (! plain_values && CONSP (o) && EQ (XCDR (o), ltv_mark))
+ o = XCAR (o);
+ return o;
}
-/* Convert an internal object to an `emacs_value'. Allocate storage
- from the environment; return NULL if allocation fails. */
+/* 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. */
static emacs_value
-lisp_to_value (emacs_env *env, Lisp_Object o)
+lisp_to_value_bits (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);
-}
+ if (plain_values || USE_LSB_TAG)
+ return XLP (o);
-/* 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)
+ /* Compress O into the space of a pointer, possibly losing information. */
+ EMACS_UINT u = XLI (o);
+ if (FIXNUMP (o))
{
- struct emacs_value_frame *current = next;
- next = current->next;
- free (current);
+ uintptr_t i = (u << VALBITS) + XTYPE (o);
+ return (emacs_value) i;
+ }
+ else
+ {
+ char *p = XLP (o);
+ void *v = p - (u & ~VALMASK) + XTYPE (o);
+ return v;
}
}
-/* Allocate a new value from STORAGE and stores OBJ in it. Return
- NULL if allocation fails and use ENV for non local exit reporting. */
+/* 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 (emacs_env *env, 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)
+ if (module_assertions)
{
- 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;
+ /* 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;
}
- emacs_value value = storage->current->objects + storage->current->offset;
- value->v = obj;
- ++storage->current->offset;
- return value;
-}
-/* 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))
+ emacs_value v = lisp_to_value_bits (o);
+
+ if (! EQ (o, value_to_lisp_bits (v)))
{
- 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);
+ /* 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);
}
+
+ eassert (EQ (o, value_to_lisp (v)));
+ return v;
}
\f
env = xmalloc (sizeof *env);
priv->pending_non_local_exit = emacs_funcall_exit_return;
- initialize_storage (&priv->storage);
+ priv->values = priv->non_local_exit_symbol = priv->non_local_exit_data = Qnil;
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;
- initialize_storage (&global_storage);
+ if (enable)
+ global_env = initialize_environment (NULL, &global_env_private);
}
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