From 6667ab0f266b12909cf0eedd025525b24d987592 Mon Sep 17 00:00:00 2001
From: Mike Pall <mike>
Date: Wed, 21 Jul 2010 21:23:45 +0200
Subject: [PATCH] Use independent hash for VM event dispatch.

---
 src/lib_jit.c    | 5 ++++-
 src/lj_vmevent.h | 8 ++++----
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/src/lib_jit.c b/src/lib_jit.c
index 033ab4c4..4cabb2f7 100644
--- a/src/lib_jit.c
+++ b/src/lib_jit.c
@@ -114,8 +114,11 @@ LJLIB_CF(jit_attach)
   GCstr *s = lj_lib_optstr(L, 2);
   luaL_findtable(L, LUA_REGISTRYINDEX, LJ_VMEVENTS_REGKEY, LJ_VMEVENTS_HSIZE);
   if (s) {  /* Attach to given event. */
+    const uint8_t *p = (const uint8_t *)strdata(s);
+    uint32_t h = s->len;
+    while (*p) h = h ^ (lj_rol(h, 6) + *p++);
     lua_pushvalue(L, 1);
-    lua_rawseti(L, -2, VMEVENT_HASHIDX(s->hash));
+    lua_rawseti(L, -2, VMEVENT_HASHIDX(h));
     G(L)->vmevmask = VMEVENT_NOCACHE;  /* Invalidate cache. */
   } else {  /* Detach if no event given. */
     setnilV(L->top++);
diff --git a/src/lj_vmevent.h b/src/lj_vmevent.h
index ceb70f82..9d21cb1e 100644
--- a/src/lj_vmevent.h
+++ b/src/lj_vmevent.h
@@ -23,10 +23,10 @@
 
 /* VM event IDs. */
 typedef enum {
-  VMEVENT_DEF(BC,	0x0000140b),
-  VMEVENT_DEF(TRACE,	0x10ea574d),
-  VMEVENT_DEF(RECORD,	0x5698231c),
-  VMEVENT_DEF(TEXIT,	0x12d984a7),
+  VMEVENT_DEF(BC,	0x00003883),
+  VMEVENT_DEF(TRACE,	0xb2d91467),
+  VMEVENT_DEF(RECORD,	0x9284bf4f),
+  VMEVENT_DEF(TEXIT,	0xb29df2b0),
   LJ_VMEVENT__MAX
 } VMEvent;