[Pkg-gnupg-commit] [gnupg2] 44/166: gpgscm: Optimize environment lookups and insertions.
Daniel Kahn Gillmor
dkg at fifthhorseman.net
Thu Mar 16 22:33:04 UTC 2017
This is an automated email from the git hooks/post-receive script.
dkg pushed a commit to branch experimental
in repository gnupg2.
commit b85d509a8f5c2e6200b8051ca1593c019abce90b
Author: Justus Winter <justus at g10code.com>
Date: Tue Jan 31 18:16:46 2017 +0100
gpgscm: Optimize environment lookups and insertions.
* tests/gpgscm/scheme.c (pointercmp): New function.
(new_slot_spec_in_env): Add and use slot for insertions.
(find_slot_spec_in_env): New variant of 'find_slot_in_env' that
returns the slot on failures.
(find_slot_in_env): Express using the new function.
(new_slot_in_env): Update callsite.
(opexe_0): Optimize lookup-or-insert.
(opexe_1): Likewise.
(scheme_define): Likewise.
--
Optimize environment lookups by keeping the lists in the hash table or
the list sorted. Optimize the insertions by passing the slot computed
by the lookup to the insertion.
Signed-off-by: Justus Winter <justus at g10code.com>
---
tests/gpgscm/scheme.c | 166 +++++++++++++++++++++++++++++++++++---------------
1 file changed, 116 insertions(+), 50 deletions(-)
diff --git a/tests/gpgscm/scheme.c b/tests/gpgscm/scheme.c
index d2c3dfc..c4af94d 100644
--- a/tests/gpgscm/scheme.c
+++ b/tests/gpgscm/scheme.c
@@ -2612,6 +2612,22 @@ static int hash_fn(const char *key, int table_size)
}
#endif
+/* Compares A and B. Returns an integer less than, equal to, or
+ * greater than zero if A is stored at a memory location that is
+ * numerical less than, equal to, or greater than that of B. */
+static int
+pointercmp(pointer a, pointer b)
+{
+ uintptr_t a_n = (uintptr_t) a;
+ uintptr_t b_n = (uintptr_t) b;
+
+ if (a_n < b_n)
+ return -1;
+ if (a_n > b_n)
+ return 1;
+ return 0;
+}
+
#ifndef USE_ALIST_ENV
/*
@@ -2639,53 +2655,75 @@ static void new_frame_in_env(scheme *sc, pointer old_env)
setenvironment(sc->envir);
}
+/* Insert (VARIABLE, VALUE) at SSLOT. SSLOT must be obtained using
+ * find_slot_spec_in_env, and no insertion must be done between
+ * obtaining SSLOT and the call to this function.
+ *
+ * If SSLOT is NULL, the new slot is put into the appropriate place in
+ * the environment vector. */
static INLINE void new_slot_spec_in_env(scheme *sc, pointer env,
- pointer variable, pointer value)
+ pointer variable, pointer value,
+ pointer *sslot)
{
#define new_slot_spec_in_env_allocates 2
pointer slot;
gc_disable(sc, gc_reservations (new_slot_spec_in_env));
slot = immutable_cons(sc, variable, value);
- if (is_vector(car(env))) {
- int location = hash_fn(symname(variable), vector_length(car(env)));
+ if (sslot == NULL) {
+ int location;
+ assert(is_vector(car(env)));
+ location = hash_fn(symname(variable), vector_length(car(env)));
set_vector_elem(car(env), location,
immutable_cons(sc, slot, vector_elem(car(env), location)));
} else {
- car(env) = immutable_cons(sc, slot, car(env));
+ *sslot = immutable_cons(sc, slot, *sslot);
}
gc_enable(sc);
}
-static pointer find_slot_in_env(scheme *sc, pointer env, pointer hdl, int all)
+/* Find the slot in ENV under the key HDL. If ALL is given, look in
+ * all environments enclosing ENV. If the lookup fails, and SSLOT is
+ * given, the position where the new slot has to be inserted is stored
+ * at SSLOT.
+ *
+ * SSLOT may be set to NULL if the new symbol should be placed at the
+ * appropriate place in the vector. */
+static pointer
+find_slot_spec_in_env(scheme *sc, pointer env, pointer hdl, int all, pointer **sslot)
{
pointer x,y;
int location;
+ pointer *sl;
+ int d;
+ assert(is_symbol(hdl));
for (x = env; x != sc->NIL; x = cdr(x)) {
if (is_vector(car(x))) {
location = hash_fn(symname(hdl), vector_length(car(x)));
+ sl = NULL;
y = vector_elem(car(x), location);
} else {
- y = car(x);
- }
- for ( ; y != sc->NIL; y = cdr(y)) {
- if (caar(y) == hdl) {
- break;
- }
- }
- if (y != sc->NIL) {
- break;
- }
- if(!all) {
- return sc->NIL;
- }
+ sl = &car(x);
+ y = *sl;
}
- if (x != sc->NIL) {
- return car(y);
+ for ( ; y != sc->NIL; sl = &cdr(y), y = *sl) {
+ d = pointercmp(caar(y), hdl);
+ if (d == 0)
+ return car(y); /* Hit. */
+ else if (d > 0)
+ break; /* Miss. */
}
- return sc->NIL;
+
+ if (x == env && sslot)
+ *sslot = sl; /* Insert here. */
+
+ if (!all)
+ return sc->NIL; /* Miss, and stop looking. */
+ }
+
+ return sc->NIL; /* Not found in any environment. */
}
#else /* USE_ALIST_ENV */
@@ -2696,41 +2734,66 @@ static INLINE void new_frame_in_env(scheme *sc, pointer old_env)
setenvironment(sc->envir);
}
+/* Insert (VARIABLE, VALUE) at SSLOT. SSLOT must be obtained using
+ * find_slot_spec_in_env, and no insertion must be done between
+ * obtaining SSLOT and the call to this function. */
static INLINE void new_slot_spec_in_env(scheme *sc, pointer env,
- pointer variable, pointer value)
+ pointer variable, pointer value,
+ pointer *sslot)
{
#define new_slot_spec_in_env_allocates 2
- car(env) = immutable_cons(sc, immutable_cons(sc, variable, value), car(env));
+ (void) env;
+ assert(is_symbol(variable));
+ *sslot = immutable_cons(sc, immutable_cons(sc, variable, value), *sslot);
}
-static pointer find_slot_in_env(scheme *sc, pointer env, pointer hdl, int all)
+/* Find the slot in ENV under the key HDL. If ALL is given, look in
+ * all environments enclosing ENV. If the lookup fails, and SSLOT is
+ * given, the position where the new slot has to be inserted is stored
+ * at SSLOT. */
+static pointer
+find_slot_spec_in_env(scheme *sc, pointer env, pointer hdl, int all, pointer **sslot)
{
pointer x,y;
+ pointer *sl;
+ int d;
+ assert(is_symbol(hdl));
+
for (x = env; x != sc->NIL; x = cdr(x)) {
- for (y = car(x); y != sc->NIL; y = cdr(y)) {
- if (caar(y) == hdl) {
- break;
- }
- }
- if (y != sc->NIL) {
- break;
- }
- if(!all) {
- return sc->NIL;
- }
- }
- if (x != sc->NIL) {
- return car(y);
+ for (sl = &car(x), y = *sl; y != sc->NIL; sl = &cdr(y), y = *sl) {
+ d = pointercmp(caar(y), hdl);
+ if (d == 0)
+ return car(y); /* Hit. */
+ else if (d > 0)
+ break; /* Miss. */
+ }
+
+ if (x == env && sslot)
+ *sslot = sl; /* Insert here. */
+
+ if (!all)
+ return sc->NIL; /* Miss, and stop looking. */
}
- return sc->NIL;
+
+ return sc->NIL; /* Not found in any environment. */
}
#endif /* USE_ALIST_ENV else */
+static pointer find_slot_in_env(scheme *sc, pointer env, pointer hdl, int all)
+{
+ return find_slot_spec_in_env(sc, env, hdl, all, NULL);
+}
+
static INLINE void new_slot_in_env(scheme *sc, pointer variable, pointer value)
{
#define new_slot_in_env_allocates new_slot_spec_in_env_allocates
- new_slot_spec_in_env(sc, sc->envir, variable, value);
+ pointer slot;
+ pointer *sslot;
+ assert(is_symbol(variable));
+ slot = find_slot_spec_in_env(sc, sc->envir, variable, 0, &sslot);
+ assert(slot == sc->NIL);
+ new_slot_spec_in_env(sc, sc->envir, variable, value, sslot);
}
static INLINE void set_slot_in_env(scheme *sc, pointer slot, pointer value)
@@ -3486,15 +3549,16 @@ static pointer opexe_0(scheme *sc, enum scheme_opcodes op) {
s_save(sc,OP_DEF1, sc->NIL, x);
s_thread_to(sc,OP_EVAL);
- CASE(OP_DEF1): /* define */
- x=find_slot_in_env(sc,sc->envir,sc->code,0);
+ CASE(OP_DEF1): { /* define */
+ pointer *sslot;
+ x = find_slot_spec_in_env(sc, sc->envir, sc->code, 0, &sslot);
if (x != sc->NIL) {
set_slot_in_env(sc, x, sc->value);
} else {
- new_slot_in_env(sc, sc->code, sc->value);
+ new_slot_spec_in_env(sc, sc->envir, sc->code, sc->value, sslot);
}
s_return(sc,sc->code);
-
+ }
CASE(OP_DEFP): /* defined? */
x=sc->envir;
@@ -3806,15 +3870,17 @@ static pointer opexe_1(scheme *sc, enum scheme_opcodes op) {
s_save(sc,OP_MACRO1, sc->NIL, x);
s_goto(sc,OP_EVAL);
- CASE(OP_MACRO1): /* macro */
+ CASE(OP_MACRO1): { /* macro */
+ pointer *sslot;
typeflag(sc->value) = T_MACRO;
- x = find_slot_in_env(sc, sc->envir, sc->code, 0);
+ x = find_slot_spec_in_env(sc, sc->envir, sc->code, 0, &sslot);
if (x != sc->NIL) {
set_slot_in_env(sc, x, sc->value);
} else {
- new_slot_in_env(sc, sc->code, sc->value);
+ new_slot_spec_in_env(sc, sc->envir, sc->code, sc->value, sslot);
}
s_return(sc,sc->code);
+ }
CASE(OP_CASE0): /* case */
s_save(sc,OP_CASE1, sc->NIL, cdr(sc->code));
@@ -5769,12 +5835,12 @@ void scheme_load_string(scheme *sc, const char *cmd) {
void scheme_define(scheme *sc, pointer envir, pointer symbol, pointer value) {
pointer x;
-
- x=find_slot_in_env(sc,envir,symbol,0);
+ pointer *sslot;
+ x = find_slot_spec_in_env(sc, envir, symbol, 0, &sslot);
if (x != sc->NIL) {
set_slot_in_env(sc, x, value);
} else {
- new_slot_spec_in_env(sc, envir, symbol, value);
+ new_slot_spec_in_env(sc, envir, symbol, value, sslot);
}
}
--
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