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[Emacs-diffs] emacs-25 4851616: Improve commentary for emacs-module.c
From: |
Eli Zaretskii |
Subject: |
[Emacs-diffs] emacs-25 4851616: Improve commentary for emacs-module.c |
Date: |
Sun, 20 Dec 2015 19:11:01 +0000 |
branch: emacs-25
commit 4851616b4d2e14cdf970b9029f0d4b00083a08f5
Author: Philipp Stephani <address@hidden>
Commit: Eli Zaretskii <address@hidden>
Improve commentary for emacs-module.c
* src/lisp.h: Document emacs-module.c assumptions about EQ and NILP.
* src/emacs-module.c (module_non_local_exit_get): Document that we
cannot use the current implementation.
(module_is_not_nil, module_eq): Document assumptions about EQ and
NILP.
---
src/emacs-module.c | 8 ++++++--
src/lisp.h | 13 ++++++++++++-
2 files changed, 18 insertions(+), 3 deletions(-)
diff --git a/src/emacs-module.c b/src/emacs-module.c
index ee97644..5d1b4dc 100644
--- a/src/emacs-module.c
+++ b/src/emacs-module.c
@@ -325,6 +325,8 @@ module_non_local_exit_get (emacs_env *env, emacs_value
*sym, emacs_value *data)
struct emacs_env_private *p = env->private_members;
if (p->pending_non_local_exit != emacs_funcall_exit_return)
{
+ /* FIXME: We cannot call lisp_to_value here because that can
+ exit non-locally. */
*sym = lisp_to_value (p->non_local_exit_symbol);
*data = lisp_to_value (p->non_local_exit_data);
}
@@ -434,6 +436,7 @@ module_is_not_nil (emacs_env *env, emacs_value value)
check_main_thread ();
if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
return false;
+ /* Assume that NILP never exits non-locally. */
return ! NILP (value_to_lisp (value));
}
@@ -443,6 +446,7 @@ module_eq (emacs_env *env, emacs_value a, emacs_value b)
check_main_thread ();
if (module_non_local_exit_check (env) != emacs_funcall_exit_return)
return false;
+ /* Assume that EQ never exits non-locally. */
return EQ (value_to_lisp (a), value_to_lisp (b));
}
@@ -889,7 +893,7 @@ value_to_lisp_bits (emacs_value v)
}
/* If V was computed from lisp_to_value (O), then return O.
- Never fails. */
+ Must never fail or exit non-locally. */
static Lisp_Object
value_to_lisp (emacs_value v)
{
@@ -919,7 +923,7 @@ enum { HAVE_STRUCT_ATTRIBUTE_ALIGNED = 0 };
#endif
/* Convert O to an emacs_value. Allocate storage if needed; this can
- signal if memory is exhausted. */
+ signal if memory is exhausted. Must be injective. */
static emacs_value
lisp_to_value (Lisp_Object o)
{
diff --git a/src/lisp.h b/src/lisp.h
index 995760a..bcac4b6 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -329,11 +329,15 @@ error !;
#define lisp_h_CHECK_TYPE(ok, predicate, x) \
((ok) ? (void) 0 : (void) wrong_type_argument (predicate, x))
#define lisp_h_CONSP(x) (XTYPE (x) == Lisp_Cons)
+/* lisp_h_EQ must never exit non-locally; emacs-module.c relies on
+ that. */
#define lisp_h_EQ(x, y) (XLI (x) == XLI (y))
#define lisp_h_FLOATP(x) (XTYPE (x) == Lisp_Float)
#define lisp_h_INTEGERP(x) ((XTYPE (x) & (Lisp_Int0 | ~Lisp_Int1)) ==
Lisp_Int0)
#define lisp_h_MARKERP(x) (MISCP (x) && XMISCTYPE (x) == Lisp_Misc_Marker)
#define lisp_h_MISCP(x) (XTYPE (x) == Lisp_Misc)
+/* lisp_h_NILP must never exit non-locally; emacs-module.c relies on
+ that. */
#define lisp_h_NILP(x) EQ (x, Qnil)
#define lisp_h_SET_SYMBOL_VAL(sym, v) \
(eassert ((sym)->redirect == SYMBOL_PLAINVAL), (sym)->val.value = (v))
@@ -382,11 +386,14 @@ error !;
# define CHECK_SYMBOL(x) lisp_h_CHECK_SYMBOL (x)
# define CHECK_TYPE(ok, predicate, x) lisp_h_CHECK_TYPE (ok, predicate, x)
# define CONSP(x) lisp_h_CONSP (x)
+/* EQ must never exit non-locally; emacs-module.c relies on that. */
# define EQ(x, y) lisp_h_EQ (x, y)
# define FLOATP(x) lisp_h_FLOATP (x)
# define INTEGERP(x) lisp_h_INTEGERP (x)
# define MARKERP(x) lisp_h_MARKERP (x)
# define MISCP(x) lisp_h_MISCP (x)
+/* NILP must never exit non-locally; emacs-module.c relies on
+ that. */
# define NILP(x) lisp_h_NILP (x)
# define SET_SYMBOL_VAL(sym, v) lisp_h_SET_SYMBOL_VAL (sym, v)
# define SYMBOL_CONSTANT_P(sym) lisp_h_SYMBOL_CONSTANT_P (sym)
@@ -988,7 +995,8 @@ make_natnum (EMACS_INT n)
return USE_LSB_TAG ? make_number (n) : XIL (n + (int0 << VALBITS));
}
-/* Return true if X and Y are the same object. */
+/* Return true if X and Y are the same object. Must never exit
+ non-locally; emacs-module.c relies on that. */
INLINE bool
(EQ) (Lisp_Object x, Lisp_Object y)
@@ -2565,6 +2573,9 @@ enum char_bits
/* Data type checking. */
+/* Checks whether X is null. Must never exit non-locally;
+ emacs-module.c relies on that. */
+
INLINE bool
(NILP) (Lisp_Object x)
{
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