From 6c7334a9ac4b424a4fd52bfeb4d674bc7cfa4eb3 Mon Sep 17 00:00:00 2001
From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Wed, 10 Apr 2002 09:11:07 -0300
Subject: [PATCH] line trace uses `savedpc' to save last `pc' seen

---
 ldebug.c | 10 +++++-----
 ldebug.h |  4 +++-
 lstate.h |  3 +--
 lvm.c    | 17 +++++++++--------
 4 files changed, 18 insertions(+), 16 deletions(-)

diff --git a/ldebug.c b/ldebug.c
index eb282db7..b34e6fff 100644
--- a/ldebug.c
+++ b/ldebug.c
@@ -1,5 +1,5 @@
 /*
-** $Id: ldebug.c,v 1.106 2002/04/04 17:21:31 roberto Exp roberto $
+** $Id: ldebug.c,v 1.107 2002/04/09 19:47:44 roberto Exp roberto $
 ** Debug Interface
 ** See Copyright Notice in lua.h
 */
@@ -37,9 +37,9 @@ static int isLmark (CallInfo *ci) {
 static int currentpc (lua_State *L, CallInfo *ci) {
   if (ci->pc == NULL) return -1;  /* function is not an active Lua function */
   if (ci == L->ci || ci->pc != (ci+1)->pc)  /* no other function using `pc'? */
-    return (*ci->pc - ci_func(ci)->l.p->code) - 1;
-  else  /* function's pc is saved */
-    return (ci->savedpc - ci_func(ci)->l.p->code) - 1;
+    ci->savedpc = *ci->pc;  /* may not be saved; save it */
+  /* function's pc is saved */
+  return pcRel(ci->savedpc, ci_func(ci)->l.p);
 }
 
 
@@ -69,7 +69,7 @@ LUA_API lua_Hook lua_setlinehook (lua_State *L, lua_Hook func) {
   oldhook = L->linehook;
   L->linehook = func;
   for (ci = L->base_ci; ci <= L->ci; ci++)
-    ci->lastpc = currentpc(L, ci);
+    currentpc(L, ci);  /* update `savedpc' */
   lua_unlock(L);
   return oldhook;
 }
diff --git a/ldebug.h b/ldebug.h
index 36b866df..4590aeba 100644
--- a/ldebug.h
+++ b/ldebug.h
@@ -1,5 +1,5 @@
 /*
-** $Id: ldebug.h,v 1.17 2002/03/19 12:45:25 roberto Exp roberto $
+** $Id: ldebug.h,v 1.18 2002/03/25 17:47:14 roberto Exp roberto $
 ** Auxiliary functions from Debug Interface module
 ** See Copyright Notice in lua.h
 */
@@ -12,6 +12,8 @@
 #include "luadebug.h"
 
 
+#define pcRel(pc, p)	(cast(int, (pc) - (p)->code) - 1)
+
 void luaG_typeerror (lua_State *L, const TObject *o, const char *opname);
 void luaG_concaterror (lua_State *L, StkId p1, StkId p2);
 void luaG_aritherror (lua_State *L, StkId p1, const TObject *p2);
diff --git a/lstate.h b/lstate.h
index a7ec7e2c..3bb3fa5d 100644
--- a/lstate.h
+++ b/lstate.h
@@ -1,5 +1,5 @@
 /*
-** $Id: lstate.h,v 1.80 2002/03/25 17:47:14 roberto Exp roberto $
+** $Id: lstate.h,v 1.81 2002/03/26 20:46:10 roberto Exp roberto $
 ** Global State
 ** See Copyright Notice in lua.h
 */
@@ -91,7 +91,6 @@ typedef struct CallInfo {
   StkId	top;  /* top for this function (when it's a Lua function) */
   const Instruction **pc;  /* points to `pc' variable in `luaV_execute' */
   StkId *pb;  /* points to `base' variable in `luaV_execute' */
-  int lastpc;  /* last pc traced */
   int yield_results;
 } CallInfo;
 
diff --git a/lvm.c b/lvm.c
index bb1b9852..9079b32b 100644
--- a/lvm.c
+++ b/lvm.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lvm.c,v 1.223 2002/03/25 17:47:14 roberto Exp roberto $
+** $Id: lvm.c,v 1.224 2002/04/09 19:47:44 roberto Exp roberto $
 ** Lua virtual machine
 ** See Copyright Notice in lua.h
 */
@@ -64,15 +64,16 @@ int luaV_tostring (lua_State *L, TObject *obj) {
 
 static void traceexec (lua_State *L) {
   CallInfo *ci = L->ci;
-  int *lineinfo = ci_func(ci)->l.p->lineinfo;
-  int pc = cast(int, *ci->pc - ci_func(ci)->l.p->code) - 1;
-  int newline = lineinfo[pc];
-  if (pc == 0)  /* tracing may be starting now? */
-    ci->lastpc = 0;  /* initialize `lastpc' */
+  Proto *p = ci_func(ci)->l.p;
+  int newline = p->lineinfo[pcRel(*ci->pc, p)];
+  if (pcRel(*ci->pc, p) == 0)  /* tracing may be starting now? */
+    ci->savedpc = *ci->pc;  /* initialize `savedpc' */
   /* calls linehook when enters a new line or jumps back (loop) */
-  if (pc <= ci->lastpc || newline != lineinfo[ci->lastpc])
+  if (*ci->pc <= ci->savedpc || newline != p->lineinfo[pcRel(ci->savedpc, p)]) {
     luaD_lineHook(L, newline);
-  L->ci->lastpc = pc;
+    ci = L->ci;  /* previous call may reallocate `ci' */
+  }
+  ci->savedpc = *ci->pc;
 }