[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Emacs-diffs] master bc78ff2 2/2: Use 0 for Qnil
From: |
Paul Eggert |
Subject: |
[Emacs-diffs] master bc78ff2 2/2: Use 0 for Qnil |
Date: |
Mon, 05 Jan 2015 18:15:13 +0000 |
branch: master
commit bc78ff2603b8c062dbd8f93f421c3412e36e343f
Author: Paul Eggert <address@hidden>
Commit: Paul Eggert <address@hidden>
Use 0 for Qnil
Fixes Bug#15880.
If USE_LSB_TAG, arrange for the representation of Qnil to be zero so
that NILP (x) is equivalent to testing whether x is 0 at the
machine level. The overall effects of this and the previous patch
shrink the size of the text segment by 2.3% and speeds up
compilation of all the .elc files by about 0.5% on my platform,
which is Fedora 20 x86-64.
* lib-src/make-docfile.c (compare_globals):
* src/lisp.h (lisp_h_XPNTR, lisp_h_XSYMBOL, lisp_h_XUNTAG)
(make_lisp_symbol) [USE_LSB_TAG]:
Symbols now tag the difference from lispsym, not the pointer.
(lisp_h_XUNTAGBASE, TAG_SYMPTR): New macros.
(Lisp_Int0, Lisp_Int1, Lisp_Symbol, Lisp_Misc, Lisp_String, Lisp_Cons):
Renumber so that Lisp_Symbol is 0, so that Qnil is zero.
(XSYMBOL): New forward decl.
(XUNTAGBASE): New function.
(XUNTAG): Use it.
---
lib-src/ChangeLog | 3 ++
lib-src/make-docfile.c | 10 ++++++++
src/ChangeLog | 18 ++++++++++++++
src/lisp.h | 59 ++++++++++++++++++++++++++++++++---------------
4 files changed, 71 insertions(+), 19 deletions(-)
diff --git a/lib-src/ChangeLog b/lib-src/ChangeLog
index 8bdf7d1..9a1fc7a 100644
--- a/lib-src/ChangeLog
+++ b/lib-src/ChangeLog
@@ -1,5 +1,8 @@
2015-01-05 Paul Eggert <address@hidden>
+ Use 0 for Qnil
+ * make-docfile.c (compare_globals): Consider 'nil' to be the least.
+
Compute C decls for DEFSYMs automatically
Fixes Bug#15880.
* make-docfile.c: Revamp to generate table of symbols, too.
diff --git a/lib-src/make-docfile.c b/lib-src/make-docfile.c
index b05a634..22c4bad 100644
--- a/lib-src/make-docfile.c
+++ b/lib-src/make-docfile.c
@@ -613,6 +613,16 @@ compare_globals (const void *a, const void *b)
if (ga->type != gb->type)
return ga->type - gb->type;
+ /* Consider "nil" to be the least, so that aQnil is firat. That
+ way, Qnil's internal representation is zero, which is a bit faster. */
+ if (ga->type == SYMBOL)
+ {
+ bool a_nil = strcmp (ga->name, "Qnil") == 0;
+ bool b_nil = strcmp (gb->name, "Qnil") == 0;
+ if (a_nil | b_nil)
+ return b_nil - a_nil;
+ }
+
return strcmp (ga->name, gb->name);
}
diff --git a/src/ChangeLog b/src/ChangeLog
index 6273799..b068056 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,23 @@
2015-01-05 Paul Eggert <address@hidden>
+ Use 0 for Qnil
+ Fixes Bug#15880.
+ If USE_LSB_TAG, arrange for the representation of Qnil to be zero so
+ that NILP (x) is equivalent to testing whether x is 0 at the
+ machine level. The overall effects of this and the previous patch
+ shrink the size of the text segment by 2.3% and speeds up
+ compilation of all the .elc files by about 0.5% on my platform,
+ which is Fedora 20 x86-64.
+ * lisp.h (lisp_h_XPNTR, lisp_h_XSYMBOL, lisp_h_XUNTAG)
+ (make_lisp_symbol) [USE_LSB_TAG]:
+ Symbols now tag the difference from lispsym, not the pointer.
+ (lisp_h_XUNTAGBASE, TAG_SYMPTR): New macros.
+ (Lisp_Int0, Lisp_Int1, Lisp_Symbol, Lisp_Misc, Lisp_String, Lisp_Cons):
+ Renumber so that Lisp_Symbol is 0, so that Qnil is zero.
+ (XSYMBOL): New forward decl.
+ (XUNTAGBASE): New function.
+ (XUNTAG): Use it.
+
Compute C decls for DEFSYMs automatically
Fixes Bug#15880.
This patch also makes Q constants (e.g., Qnil) constant addresses
diff --git a/src/lisp.h b/src/lisp.h
index 962fed4..fc04ab9 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -354,9 +354,11 @@ error !;
#define lisp_h_XCONS(a) \
(eassert (CONSP (a)), (struct Lisp_Cons *) XUNTAG (a, Lisp_Cons))
#define lisp_h_XHASH(a) XUINT (a)
-#define lisp_h_XPNTR(a) ((void *) (intptr_t) (XLI (a) & VALMASK))
+#define lisp_h_XPNTR(a) \
+ (SYMBOLP (a) ? XSYMBOL (a) : (void *) ((intptr_t) (XLI (a) & VALMASK)))
#define lisp_h_XSYMBOL(a) \
- (eassert (SYMBOLP (a)), (struct Lisp_Symbol *) XUNTAG (a, Lisp_Symbol))
+ (eassert (SYMBOLP (a)), \
+ (struct Lisp_Symbol *) XUNTAGBASE (a, Lisp_Symbol, lispsym))
#ifndef GC_CHECK_CONS_LIST
# define lisp_h_check_cons_list() ((void) 0)
#endif
@@ -366,7 +368,9 @@ error !;
# define lisp_h_XFASTINT(a) XINT (a)
# define lisp_h_XINT(a) (XLI (a) >> INTTYPEBITS)
# define lisp_h_XTYPE(a) ((enum Lisp_Type) (XLI (a) & ~VALMASK))
-# define lisp_h_XUNTAG(a, type) ((void *) (XLI (a) - (type)))
+# define lisp_h_XUNTAG(a, type) XUNTAGBASE (a, type, 0)
+# define lisp_h_XUNTAGBASE(a, type, base) \
+ ((void *) ((char *) (base) - (type) + (intptr_t) XLI (a)))
#endif
/* When compiling via gcc -O0, define the key operations as macros, as
@@ -408,6 +412,7 @@ error !;
# define XINT(a) lisp_h_XINT (a)
# define XTYPE(a) lisp_h_XTYPE (a)
# define XUNTAG(a, type) lisp_h_XUNTAG (a, type)
+# define XUNTAGBASE(a, type, base) lisp_h_XUNTAGBASE (a, type, base)
# endif
#endif
@@ -447,20 +452,20 @@ error !;
enum Lisp_Type
{
- /* Integer. XINT (obj) is the integer value. */
- Lisp_Int0 = 0,
- Lisp_Int1 = USE_LSB_TAG ? 1 << INTTYPEBITS : 1,
-
/* Symbol. XSYMBOL (object) points to a struct Lisp_Symbol. */
- Lisp_Symbol = 2,
+ Lisp_Symbol = 0,
/* Miscellaneous. XMISC (object) points to a union Lisp_Misc,
whose first member indicates the subtype. */
- Lisp_Misc = 3,
+ Lisp_Misc = 1,
+
+ /* Integer. XINT (obj) is the integer value. */
+ Lisp_Int0 = 2,
+ Lisp_Int1 = USE_LSB_TAG ? 6 : 3,
/* String. XSTRING (object) points to a struct Lisp_String.
The length of the string, and its contents, are stored therein. */
- Lisp_String = USE_LSB_TAG ? 1 : 1 << INTTYPEBITS,
+ Lisp_String = 4,
/* Vector of Lisp objects, or something resembling it.
XVECTOR (object) points to a struct Lisp_Vector, which contains
@@ -469,7 +474,7 @@ enum Lisp_Type
Lisp_Vectorlike = 5,
/* Cons. XCONS (object) points to a struct Lisp_Cons. */
- Lisp_Cons = 6,
+ Lisp_Cons = USE_LSB_TAG ? 3 : 6,
Lisp_Float = 7
};
@@ -604,6 +609,8 @@ INLINE bool SUB_CHAR_TABLE_P (Lisp_Object);
INLINE bool SUBRP (Lisp_Object);
INLINE bool (SYMBOLP) (Lisp_Object);
INLINE bool (VECTORLIKEP) (Lisp_Object);
+INLINE struct Lisp_Symbol *XSYMBOL (Lisp_Object);
+INLINE void *(XUNTAGBASE) (Lisp_Object, int, void *);
INLINE bool WINDOWP (Lisp_Object);
INLINE struct Lisp_Save_Value *XSAVE_VALUE (Lisp_Object);
@@ -720,6 +727,10 @@ struct Lisp_Symbol
#define TAG_PTR(tag, ptr) \
((USE_LSB_TAG ? (tag) : (EMACS_UINT) (tag) << VALBITS) + (uintptr_t) (ptr))
+/* Yield an integer that tags PTR as a symbol. */
+#define TAG_SYMPTR(ptr) \
+ TAG_PTR (Lisp_Symbol, (char *) (ptr) - (char *) (USE_LSB_TAG ? lispsym : 0))
+
/* Declare extern constants for Lisp symbols. These can be helpful
when using a debugger like GDB, on older platforms where the debug
format does not represent C macros. Athough these symbols are
@@ -727,7 +738,7 @@ struct Lisp_Symbol
#define DEFINE_LISP_SYMBOL_BEGIN(name) \
DEFINE_GDB_SYMBOL_BEGIN (Lisp_Object, name)
#define DEFINE_LISP_SYMBOL_END(name) \
- DEFINE_GDB_SYMBOL_END (LISP_INITIALLY (TAG_PTR (Lisp_Symbol, name)))
+ DEFINE_GDB_SYMBOL_END (LISP_INITIALLY (TAG_SYMPTR (name)))
#include "globals.h"
@@ -818,6 +829,8 @@ LISP_MACRO_DEFUN (XINT, EMACS_INT, (Lisp_Object a), (a))
LISP_MACRO_DEFUN (XFASTINT, EMACS_INT, (Lisp_Object a), (a))
LISP_MACRO_DEFUN (XTYPE, enum Lisp_Type, (Lisp_Object a), (a))
LISP_MACRO_DEFUN (XUNTAG, void *, (Lisp_Object a, int type), (a, type))
+LISP_MACRO_DEFUN (XUNTAGBASE, void *, (Lisp_Object a, int type, void *base),
+ (a, type, base))
#else /* ! USE_LSB_TAG */
@@ -878,16 +891,21 @@ XTYPE (Lisp_Object a)
return USE_LSB_TAG ? i & ~VALMASK : i >> VALBITS;
}
+/* Extract A's pointer value, assuming A's type is TYPE.
+ If USE_LSB_TAG, add BASE to A's pointer value while extracting. */
+INLINE void *
+XUNTAGBASE (Lisp_Object a, int type, void *base)
+{
+ char *b = USE_LSB_TAG ? base : 0;
+ intptr_t i = USE_LSB_TAG ? XLI (a) - type : XLI (a) & VALMASK;
+ return b + i;
+}
+
/* Extract A's pointer value, assuming A's type is TYPE. */
INLINE void *
XUNTAG (Lisp_Object a, int type)
{
- if (USE_LSB_TAG)
- {
- intptr_t i = XLI (a) - type;
- return (void *) i;
- }
- return XPNTR (a);
+ return XUNTAGBASE (a, type, 0);
}
#endif /* ! USE_LSB_TAG */
@@ -1032,7 +1050,10 @@ make_lisp_ptr (void *ptr, enum Lisp_Type type)
INLINE Lisp_Object
make_lisp_symbol (struct Lisp_Symbol *sym)
{
- return make_lisp_ptr (sym, Lisp_Symbol);
+ Lisp_Object a = XIL (TAG_SYMPTR (sym));
+ eassert (XTYPE (a) == Lisp_Symbol
+ && XUNTAGBASE (a, Lisp_Symbol, lispsym) == sym);
+ return a;
}
INLINE Lisp_Object