[Qemu-devel] [PATCH 2/8] tcg: Use a GHashTable for tcg_find_helper

[Richard Henderson <rth@twiddle.net>]

Slightly changes the interface, in that we now return name
instead of a TCGHelperInfo structure, which goes away.

Signed-off-by: Richard Henderson <rth@twiddle.net>
---
 tcg/tcg.c | 74 ++++++++++++++++-----------------------------------------------
 tcg/tcg.h | 10 +--------
 2 files changed, 19 insertions(+), 65 deletions(-)

diff --git a/tcg/tcg.c b/tcg/tcg.c
index fd7fb6b..98b1c37 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -623,20 +623,15 @@ int tcg_check_temp_count(void)
 void tcg_register_helper(void *func, const char *name)
 {
     TCGContext *s = &tcg_ctx;
-    int n;
-    if ((s->nb_helpers + 1) > s->allocated_helpers) {
-        n = s->allocated_helpers;
-        if (n == 0) {
-            n = 4;
-        } else {
-            n *= 2;
-        }
-        s->helpers = realloc(s->helpers, n * sizeof(TCGHelperInfo));
-        s->allocated_helpers = n;
+    GHashTable *table = s->helpers;
+
+    if (table == NULL) {
+        /* Use g_direct_hash/equal for direct pointer comparisons on func.  */
+        table = g_hash_table_new(NULL, NULL);
+        s->helpers = table;
     }
-    s->helpers[s->nb_helpers].func = (uintptr_t)func;
-    s->helpers[s->nb_helpers].name = name;
-    s->nb_helpers++;
+
+    g_hash_table_insert(table, (gpointer)func, (gpointer)name);
 }
 
 /* Note: we convert the 64 bit args to 32 bit and do some alignment
@@ -851,47 +846,14 @@ char *tcg_get_arg_str_i64(TCGContext *s, char *buf, int buf_size, TCGv_i64 arg)
     return tcg_get_arg_str_idx(s, buf, buf_size, GET_TCGV_I64(arg));
 }
 
-static int helper_cmp(const void *p1, const void *p2)
+/* Find helper name.  */
+static inline const char *tcg_find_helper(TCGContext *s, uintptr_t val)
 {
-    const TCGHelperInfo *th1 = p1;
-    const TCGHelperInfo *th2 = p2;
-    if (th1->func < th2->func)
-        return -1;
-    else if (th1->func == th2->func)
-        return 0;
-    else
-        return 1;
-}
-
-/* find helper definition (Note: A hash table would be better) */
-static TCGHelperInfo *tcg_find_helper(TCGContext *s, uintptr_t val)
-{
-    int m, m_min, m_max;
-    TCGHelperInfo *th;
-    uintptr_t v;
-
-    if (unlikely(!s->helpers_sorted)) {
-        qsort(s->helpers, s->nb_helpers, sizeof(TCGHelperInfo), 
-              helper_cmp);
-        s->helpers_sorted = 1;
-    }
-
-    /* binary search */
-    m_min = 0;
-    m_max = s->nb_helpers - 1;
-    while (m_min <= m_max) {
-        m = (m_min + m_max) >> 1;
-        th = &s->helpers[m];
-        v = th->func;
-        if (v == val)
-            return th;
-        else if (val < v) {
-            m_max = m - 1;
-        } else {
-            m_min = m + 1;
-        }
+    const char *ret = NULL;
+    if (s->helpers) {
+	ret = g_hash_table_lookup(s->helpers, (gpointer)val);
     }
-    return NULL;
+    return ret;
 }
 
 static const char * const cond_name[] =
@@ -976,7 +938,7 @@ void tcg_dump_ops(TCGContext *s)
             }
         } else if (c == INDEX_op_movi_i32 || c == INDEX_op_movi_i64) {
             tcg_target_ulong val;
-            TCGHelperInfo *th;
+            const char *name;
 
             nb_oargs = def->nb_oargs;
             nb_iargs = def->nb_iargs;
@@ -984,9 +946,9 @@ void tcg_dump_ops(TCGContext *s)
             qemu_log(" %s %s,$", def->name,
                      tcg_get_arg_str_idx(s, buf, sizeof(buf), args[0]));
             val = args[1];
-            th = tcg_find_helper(s, val);
-            if (th) {
-                qemu_log("%s", th->name);
+            name = tcg_find_helper(s, val);
+            if (name) {
+                qemu_log("%s", name);
             } else {
                 if (c == INDEX_op_movi_i32) {
                     qemu_log("0x%x", (uint32_t)val);
diff --git a/tcg/tcg.h b/tcg/tcg.h
index 20543f6..8c5eb42 100644
--- a/tcg/tcg.h
+++ b/tcg/tcg.h
@@ -405,11 +405,6 @@ typedef struct TCGTemp {
     const char *name;
 } TCGTemp;
 
-typedef struct TCGHelperInfo {
-    uintptr_t func;
-    const char *name;
-} TCGHelperInfo;
-
 typedef struct TCGContext TCGContext;
 
 struct TCGContext {
@@ -447,10 +442,7 @@ struct TCGContext {
     uint8_t *code_ptr;
     TCGTemp temps[TCG_MAX_TEMPS]; /* globals first, temps after */
 
-    TCGHelperInfo *helpers;
-    int nb_helpers;
-    int allocated_helpers;
-    int helpers_sorted;
+    GHashTable *helpers;
 
 #ifdef CONFIG_PROFILER
     /* profiling info */
-- 
1.8.1.4