qht: require a default comparison function

qht_lookup now uses the default cmp function. qht_lookup_custom is defined
to retain the old behaviour, that is a cmp function is explicitly provided.

qht_insert will gain use of the default cmp in the next patch.

Note that we move qht_lookup_custom's @func to be the last argument,
which makes the new qht_lookup as simple as possible.
Instead of this (i.e. keeping @func 2nd):
0000000000010750 <qht_lookup>:
   10750:       89 d1                   mov    %edx,%ecx
   10752:       48 89 f2                mov    %rsi,%rdx
   10755:       48 8b 77 08             mov    0x8(%rdi),%rsi
   10759:       e9 22 ff ff ff          jmpq   10680 <qht_lookup_custom>
   1075e:       66 90                   xchg   %ax,%ax

We get:
0000000000010740 <qht_lookup>:
   10740:       48 8b 4f 08             mov    0x8(%rdi),%rcx
   10744:       e9 37 ff ff ff          jmpq   10680 <qht_lookup_custom>
   10749:       0f 1f 80 00 00 00 00    nopl   0x0(%rax)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 15 insertions, 1 deletions

diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
index d48b56ca38..f39123bd5a 100644
--- a/accel/tcg/translate-all.c
+++ b/accel/tcg/translate-all.c
@@ -782,11 +782,25 @@ static inline void code_gen_alloc(size_t tb_size)
     qemu_mutex_init(&tb_ctx.tb_lock);
 }
 
+static bool tb_cmp(const void *ap, const void *bp)
+{
+    const TranslationBlock *a = ap;
+    const TranslationBlock *b = bp;
+
+    return a->pc == b->pc &&
+        a->cs_base == b->cs_base &&
+        a->flags == b->flags &&
+        (tb_cflags(a) & CF_HASH_MASK) == (tb_cflags(b) & CF_HASH_MASK) &&
+        a->trace_vcpu_dstate == b->trace_vcpu_dstate &&
+        a->page_addr[0] == b->page_addr[0] &&
+        a->page_addr[1] == b->page_addr[1];
+}
+
 static void tb_htable_init(void)
 {
     unsigned int mode = QHT_MODE_AUTO_RESIZE;
 
-    qht_init(&tb_ctx.htable, CODE_GEN_HTABLE_SIZE, mode);
+    qht_init(&tb_ctx.htable, tb_cmp, CODE_GEN_HTABLE_SIZE, mode);
 }
 
 /* Must be called before using the QEMU cpus. 'tb_size' is the size