lua LCD (Lua Compact Debug) patch

LCD developed 9/2015 by Terry Ellison

 We've already discarded the ldebug module from lua
 it only makes sense to discard the debug info as well
 adds 1.5 K to the binary
 saves 8 Kb on the base state
 once scripts start getting called i've seen 10-50Kb savings but it all depends on
 what exactly you are running

Change-Id: Ibb74f344df1c4c96380ec6c98b010a810e9ae9cc

apps/plugins/lua/ldebug.c

@@ -180,16 +180,111 @@ static void collectvalidlines (lua_State *L, Closure *f) {
   }
   else {
     Table *t = luaH_new(L, 0, 0);
+#ifdef LUA_OPTIMIZE_DEBUG
+    int line = 0;
+    unsigned char *p = f->l.p->packedlineinfo;
+    if (p) {
+      for (; *p && *p != INFO_FILL_BYTE; ) {
+        if (*p & INFO_DELTA_MASK) { /* line delta */
+          int delta = *p & INFO_DELTA_6BITS;
+          unsigned char sign = *p++ & INFO_SIGN_MASK;
+          int shift;
+          for (shift = 6; *p & INFO_DELTA_MASK; p++, shift += 7) {
+            delta += (*p & INFO_DELTA_7BITS)<<shift;
+          }
+          line += sign ? -delta : delta+2;
+        } else {
+          line++;
+        }
+        p++;
+        setbvalue(luaH_setnum(L, t, line), 1);
+      }
+    }
+#else
     int *lineinfo = f->l.p->lineinfo;
     int i;
     for (i=0; i<f->l.p->sizelineinfo; i++)
       setbvalue(luaH_setnum(L, t, lineinfo[i]), 1);
-    sethvalue(L, L->top, t); 
+#endif
+    sethvalue(L, L->top, t);
   }
   incr_top(L);
 }
 
 
+#ifdef LUA_OPTIMIZE_DEBUG
+/*
+ * This may seem expensive but this is only accessed frequently in traceexec
+ * and the while loop will be executed roughly half the number of non-blank
+ * source lines in the Lua function and these tend to be short.
+ */
+LUAI_FUNC int luaG_getline (const Proto *f, int pc) {
+  int line = 0, thispc = 0, nextpc;
+  unsigned char *p;
+
+  for (p = f->packedlineinfo; *p && *p != INFO_FILL_BYTE;) {
+    if (*p & INFO_DELTA_MASK) { /* line delta */
+      int delta = *p & INFO_DELTA_6BITS;
+      unsigned char sign = *p++ & INFO_SIGN_MASK;
+      int shift;
+      for (shift = 6; *p & INFO_DELTA_MASK; p++, shift += 7) {
+        delta += (*p & INFO_DELTA_7BITS)<<shift;
+      }
+      line += sign ? -delta : delta+2;
+    } else {
+      line++;
+    }
+    lua_assert(*p<127);
+    nextpc = thispc + *p++;
+    if (thispc <= pc && pc < nextpc) {
+      return line;
+    }
+    thispc = nextpc;
+  }
+  lua_assert(0);
+  return 0;
+}
+
+
+static int stripdebug (lua_State *L, Proto *f, const int level) {
+  int len = 0;
+  TString* dummy;
+  switch (level) {
+    case 3:
+      len += f->sizelineinfo;
+      f->packedlineinfo = luaM_freearray(L, f->packedlineinfo, f->sizelineinfo, unsigned char);
+    case 2:
+      len += f->sizelocvars * (sizeof(struct LocVar) + sizeof(dummy->tsv) + sizeof(struct LocVar *));
+      f->locvars = luaM_freearray(L, f->locvars, f->sizelocvars, struct LocVar);
+      f->upvalues = luaM_freearray(L, f->upvalues, f->sizeupvalues, TString *);
+      len += f->sizelocvars * (sizeof(struct LocVar) + sizeof(dummy->tsv) + sizeof(struct LocVar *)) +
+             f->sizeupvalues * (sizeof(dummy->tsv) + sizeof(TString *));
+      f->sizelocvars = 0;
+      f->sizeupvalues = 0;
+    case 1:
+    default:
+      break;
+  }
+  return len;
+}
+
+
+/* This is a recursive function so it's stack size has been kept to a minimum! */
+LUAI_FUNC int luaG_stripdebug (lua_State *L, Proto *f, int level, int recv){
+  int len = 0, i;
+#ifndef LUA_OPTIMIZE_DEBUG_USER /* gcc doesn't realize level can't be changed */
+  level = LUA_OPTIMIZE_DEBUG;
+#endif
+  if (recv > 0 && f->sizep != 0) {
+    /* recv limits recursion depth */
+    for(i=0;i<f->sizep;i++) len += luaG_stripdebug(L, f->p[i], level, --recv);
+  }
+  len += stripdebug (L, f, level);
+  return len;
+}
+#endif
+
+
 static int auxgetinfo (lua_State *L, const char *what, lua_Debug *ar,
                     Closure *f, CallInfo *ci) {
   int status = 1;
@@ -279,7 +374,9 @@ static int precheck (const Proto *pt) {
   check(!(pt->is_vararg & VARARG_NEEDSARG) ||
               (pt->is_vararg & VARARG_HASARG));
   check(pt->sizeupvalues <= pt->nups);
+#ifndef LUA_OPTIMIZE_DEBUG
   check(pt->sizelineinfo == pt->sizecode || pt->sizelineinfo == 0);
+#endif
   check(pt->sizecode > 0 && GET_OPCODE(pt->code[pt->sizecode-1]) == OP_RETURN);
   return 1;
 }