[Pkg-gnupg-commit] [gnupg2] 12/180: gpgscm: Use a static pool of cells for small integers.
Daniel Kahn Gillmor
dkg at fifthhorseman.net
Sat Dec 24 22:29:02 UTC 2016
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dkg pushed a commit to branch master
in repository gnupg2.
commit 66834eb838a8892d088f6b7332084a64d9f15008
Author: Justus Winter <justus at g10code.com>
Date: Wed Nov 16 11:29:34 2016 +0100
gpgscm: Use a static pool of cells for small integers.
* tests/gpgscm/scheme-private.h (struct scheme): New fields for the
static integer cells.
* tests/gpgscm/scheme.c (_alloc_cellseg): New function.
(alloc_cellseg): Use the new function.
(MAX_SMALL_INTEGER): New macro.
(initialize_small_integers): New function.
(mk_small_integer): Likewise.
(mk_integer): Return a small integer if possible.
(_s_return): Do not free 'op' if it is a small integer.
(s_save): Use a small integer to box the opcode.
(scheme_init_custom_alloc): Initialize small integers.
(scheme_deinit): Free chunk of small integers.
* tests/gpgscm/scheme.h (USE_SMALL_INTEGERS): New macro.
Signed-off-by: Justus Winter <justus at g10code.com>
---
tests/gpgscm/scheme-private.h | 6 +++
tests/gpgscm/scheme.c | 113 +++++++++++++++++++++++++++++++++++-------
tests/gpgscm/scheme.h | 8 +++
3 files changed, 108 insertions(+), 19 deletions(-)
diff --git a/tests/gpgscm/scheme-private.h b/tests/gpgscm/scheme-private.h
index aa78894..2c5c749 100644
--- a/tests/gpgscm/scheme-private.h
+++ b/tests/gpgscm/scheme-private.h
@@ -119,6 +119,12 @@ pointer SHARP_HOOK; /* *sharp-hook* */
pointer COMPILE_HOOK; /* *compile-hook* */
#endif
+#if USE_SMALL_INTEGERS
+/* A fixed allocation of small integers. */
+void *integer_alloc;
+pointer integer_cells;
+#endif
+
pointer free_cell; /* pointer to top of free cells */
long fcells; /* # of free cells */
size_t inhibit_gc; /* nesting of gc_disable */
diff --git a/tests/gpgscm/scheme.c b/tests/gpgscm/scheme.c
index ee8992e..a7d3fd7 100644
--- a/tests/gpgscm/scheme.c
+++ b/tests/gpgscm/scheme.c
@@ -598,34 +598,47 @@ static long binary_decode(const char *s) {
return x;
}
+/* Allocate a new cell segment but do not make it available yet. */
+static int
+_alloc_cellseg(scheme *sc, size_t len, void **alloc, pointer *cells)
+{
+ int adj = ADJ;
+ void *cp;
+
+ if (adj < sizeof(struct cell))
+ adj = sizeof(struct cell);
+
+ cp = sc->malloc(len * sizeof(struct cell) + adj);
+ if (cp == NULL)
+ return 1;
+
+ *alloc = cp;
+
+ /* adjust in TYPE_BITS-bit boundary */
+ if (((unsigned long) cp) % adj != 0)
+ cp = (void *) (adj * ((unsigned long) cp / adj + 1));
+
+ *cells = cp;
+ return 0;
+}
+
/* allocate new cell segment */
static int alloc_cellseg(scheme *sc, int n) {
pointer newp;
pointer last;
pointer p;
- void *cp;
long i;
int k;
- int adj=ADJ;
-
- if(adj<sizeof(struct cell)) {
- adj=sizeof(struct cell);
- }
for (k = 0; k < n; k++) {
if (sc->last_cell_seg >= CELL_NSEGMENT - 1)
return k;
- cp = sc->malloc(CELL_SEGSIZE * sizeof(struct cell)+adj);
- if (cp == 0)
- return k;
- i = ++sc->last_cell_seg ;
- sc->alloc_seg[i] = cp;
- /* adjust in TYPE_BITS-bit boundary */
- if(((unsigned long)cp)%adj!=0) {
- cp=(void *)(adj*((unsigned long)cp/adj+1));
- }
+ i = ++sc->last_cell_seg;
+ if (_alloc_cellseg(sc, CELL_SEGSIZE, &sc->alloc_seg[i], &newp)) {
+ sc->last_cell_seg--;
+ return k;
+ }
/* insert new segment in address order */
- newp=(pointer)cp;
sc->cell_seg[i] = newp;
while (i > 0 && sc->cell_seg[i - 1] > sc->cell_seg[i]) {
p = sc->cell_seg[i];
@@ -1128,16 +1141,64 @@ INTERFACE pointer mk_character(scheme *sc, int c) {
return (x);
}
+
+
+#if USE_SMALL_INTEGERS
+
+/* s_save assumes that all opcodes can be expressed as a small
+ * integer. */
+#define MAX_SMALL_INTEGER OP_MAXDEFINED
+
+static int
+initialize_small_integers(scheme *sc)
+{
+ int i;
+ if (_alloc_cellseg(sc, MAX_SMALL_INTEGER, &sc->integer_alloc,
+ &sc->integer_cells))
+ return 1;
+
+ for (i = 0; i < MAX_SMALL_INTEGER; i++) {
+ pointer x = &sc->integer_cells[i];
+ typeflag(x) = T_NUMBER | T_ATOM | MARK;
+ ivalue_unchecked(x) = i;
+ set_num_integer(x);
+ }
+
+ return 0;
+}
+
+static INLINE pointer
+mk_small_integer(scheme *sc, long n)
+{
+#define mk_small_integer_allocates 0
+ assert(0 <= n && n < MAX_SMALL_INTEGER);
+ return &sc->integer_cells[n];
+}
+#else
+
+#define mk_small_integer_allocates 1
+#define mk_small_integer mk_integer
+
+#endif
+
/* get number atom (integer) */
INTERFACE pointer mk_integer(scheme *sc, long n) {
- pointer x = get_cell(sc,sc->NIL, sc->NIL);
+ pointer x;
+
+#if USE_SMALL_INTEGERS
+ if (0 <= n && n < MAX_SMALL_INTEGER)
+ return mk_small_integer(sc, n);
+#endif
+ x = get_cell(sc,sc->NIL, sc->NIL);
typeflag(x) = (T_NUMBER | T_ATOM);
ivalue_unchecked(x)= n;
set_num_integer(x);
return (x);
}
+
+
INTERFACE pointer mk_real(scheme *sc, double n) {
pointer x = get_cell(sc,sc->NIL, sc->NIL);
@@ -2645,7 +2706,9 @@ static pointer _s_return(scheme *sc, pointer a, int enable_gc) {
return sc->NIL;
free_cons(sc, dump, &op, &dump);
sc->op = ivalue(op);
+#ifndef USE_SMALL_INTEGERS
free_cell(sc, op);
+#endif
free_cons(sc, dump, &sc->args, &dump);
free_cons(sc, dump, &sc->envir, &dump);
free_cons(sc, dump, &sc->code, &sc->dump);
@@ -2653,12 +2716,12 @@ static pointer _s_return(scheme *sc, pointer a, int enable_gc) {
}
static void s_save(scheme *sc, enum scheme_opcodes op, pointer args, pointer code) {
-#define s_save_allocates 5
+#define s_save_allocates (4 + mk_small_integer_allocates)
pointer dump;
gc_disable(sc, gc_reservations (s_save));
dump = cons(sc, sc->envir, cons(sc, (code), sc->dump));
dump = cons(sc, (args), dump);
- sc->dump = cons(sc, mk_integer(sc, (long)(op)), dump);
+ sc->dump = cons(sc, mk_small_integer(sc, (long)(op)), dump);
gc_enable(sc);
}
@@ -4907,6 +4970,14 @@ int scheme_init_custom_alloc(scheme *sc, func_alloc malloc, func_dealloc free) {
sc->T = &sc->_HASHT;
sc->F = &sc->_HASHF;
sc->EOF_OBJ=&sc->_EOF_OBJ;
+
+#if USE_SMALL_INTEGERS
+ if (initialize_small_integers(sc)) {
+ sc->no_memory=1;
+ return 0;
+ }
+#endif
+
sc->free_cell = &sc->_NIL;
sc->fcells = 0;
sc->inhibit_gc = GC_ENABLED;
@@ -5052,6 +5123,10 @@ void scheme_deinit(scheme *sc) {
sc->gc_verbose=0;
gc(sc,sc->NIL,sc->NIL);
+#if USE_SMALL_INTEGERS
+ sc->free(sc->integer_alloc);
+#endif
+
for(i=0; i<=sc->last_cell_seg; i++) {
sc->free(sc->alloc_seg[i]);
}
diff --git a/tests/gpgscm/scheme.h b/tests/gpgscm/scheme.h
index 8e93177..2b5b066 100644
--- a/tests/gpgscm/scheme.h
+++ b/tests/gpgscm/scheme.h
@@ -43,6 +43,7 @@ extern "C" {
# define USE_COMPILE_HOOK 0
# define USE_DL 0
# define USE_PLIST 0
+# define USE_SMALL_INTEGERS 0
#endif
@@ -95,6 +96,13 @@ extern "C" {
# define USE_THREADED_CODE 1
#endif
+/* Use a static set of cells to represent small numbers. This set
+ * notably includes all opcodes, and hence saves a cell reservation
+ * during 's_save'. */
+#ifndef USE_SMALL_INTEGERS
+# define USE_SMALL_INTEGERS 1
+#endif
+
#ifndef USE_STRCASECMP /* stricmp for Unix */
# define USE_STRCASECMP 0
#endif
--
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