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/lbaselib.c

@@ -19,6 +19,13 @@
 #include "lauxlib.h"
 #include "lualib.h"
 
+#ifdef LUA_OPTIMIZE_DEBUG_USER
+#include "lobject.h"
+#include "lstate.h"
+#include "ldebug.h"
+#include "lfunc.h"
+#endif
+
 
 
 
@@ -302,6 +309,70 @@ static int luaB_loadfile (lua_State *L) {
 }
 
 
+#ifdef LUA_OPTIMIZE_DEBUG_USER
+/* stripdebug([level[, function]]).
+ * level:    1 don't discard debug
+ *           2 discard Local and Upvalue debug info
+ *           3 discard Local, Upvalue and lineno debug info.
+ * function: Function to be stripped as per setfenv except 0 not permitted.
+ * If no arguments then the current default setting is returned.
+ * If function is omitted, this is the default setting for future compiles
+ * The function returns an estimated integer count of the bytes stripped.
+ */
+static int luaB_stripdebug (lua_State *L) {
+  int level;
+
+  if (L->top == L->base) {
+    lua_pushlightuserdata(L, &luaG_stripdebug);
+    lua_gettable(L, LUA_REGISTRYINDEX);
+    if (lua_isnil(L, -1)) {
+      lua_pop(L, 1);
+      lua_pushinteger(L, LUA_OPTIMIZE_DEBUG);
+    }
+    return 1;
+  }
+
+  level = luaL_checkint(L, 1);
+  if ((level <= 0) || (level > 3)) luaL_argerror(L, 1, "must in range 1-3");
+
+  if (L->top == L->base + 1) {
+    /* Store the default level in the registry if no function parameter */
+    lua_pushlightuserdata(L, &luaG_stripdebug);
+    lua_pushinteger(L, level);
+    lua_settable(L, LUA_REGISTRYINDEX);
+    lua_settop(L,0);
+    return 0;
+  }
+
+  if (level == 1) {
+    lua_settop(L,0);
+    lua_pushinteger(L, 0);
+    return 1;
+  }
+
+  if (!lua_isfunction(L, 2)) {
+    int scope = luaL_checkint(L, 2);
+    if (scope > 0) {
+      /* if the function parameter is a +ve integer then climb to find function */
+      lua_Debug ar;
+      lua_pop(L, 1); /* pop level as getinfo will replace it by the function */
+      if (lua_getstack(L, scope, &ar)) {
+        lua_getinfo(L, "f", &ar);
+      }
+    }
+  }
+
+  if(!lua_isfunction(L, 2) || lua_iscfunction(L, -1)) luaL_argerror(L, 2, "must be a Lua Function");
+  // lua_lock(L);
+  Proto *f = clvalue(L->base + 1)->l.p;
+  // lua_unlock(L);
+  lua_settop(L,0);
+  lua_pushinteger(L, luaG_stripdebug(L, f, level, 16));
+  return 1;
+}
+#endif
+
+
 /*
 ** Reader for generic `load' function: `lua_load' uses the
 ** stack for internal stuff, so the reader cannot change the
@@ -482,6 +553,9 @@ static const luaL_Reg base_funcs[] = {
   {"select", luaB_select},
   {"setfenv", luaB_setfenv},
   {"setmetatable", luaB_setmetatable},
+#ifdef LUA_OPTIMIZE_DEBUG_USER
+  {"stripdebug", luaB_stripdebug},
+#endif
   {"tonumber", luaB_tonumber},
   {"tostring", luaB_tostring},
   {"type", luaB_type},

apps/plugins/lua/lcode.c

@@ -784,8 +784,95 @@ void luaK_posfix (FuncState *fs, BinOpr op, expdesc *e1, expdesc *e2) {
 }
 
 
+#ifdef LUA_OPTIMIZE_DEBUG
+/*
+ * Attempted to write to last (null terminator) byte of lineinfo, so need
+ * to grow the lineinfo vector and extend the fill bytes
+ */
+static unsigned char *growLineInfo(FuncState *fs) {
+  Proto *f = fs->f;
+  int start = (f->sizelineinfo > 0 ? f->sizelineinfo - 1 : 0);
+
+  unsigned char *p;
+
+  lua_assert(f->packedlineinfo==NULL || f->packedlineinfo[start] == '\0');
+
+  /* using the macro results in a redundant if test, but what the hell */
+  luaM_growvector(fs->L, f->packedlineinfo, f->sizelineinfo, f->sizelineinfo,
+                  unsigned char, MAX_INT, "code size overflow");
+
+  p = &f->packedlineinfo[start];
+  memset(p, INFO_FILL_BYTE, f->sizelineinfo - start);
+  f->packedlineinfo[f->sizelineinfo - 1] = '\0';
+  return p;
+}
+
+
+static void generateInfoDeltaLine(FuncState *fs, int line) {
+  /* Handle first time through when lineinfo points is NULL */
+  unsigned char mask = INFO_DELTA_MASK;
+  unsigned char *p = fs->f->packedlineinfo ? lineInfoTop(fs) + 1 : growLineInfo(fs);
+#define addDLbyte(v) if (*p=='\0') p = growLineInfo(fs); *p++ = (v);
+  int delta = line - fs->lastline - 1;
+  if (delta != 0) {
+    if (delta < 0) {
+      delta = -delta;
+      mask |= INFO_SIGN_MASK;
+    }
+    delta -= 1;
+    mask |= (delta & INFO_DELTA_6BITS);
+    delta >>= 6;
+    addDLbyte(mask);
+
+    while (delta > 0) {
+      mask = INFO_DELTA_MASK | (delta & INFO_DELTA_7BITS);
+      delta >>= 7;
+      addDLbyte(mask);
+    }
+  }
+  addDLbyte(1);
+  fs->lastline = line;
+  fs->lastlineOffset = p - fs->f->packedlineinfo - 1;
+#undef addDLbyte
+}
+#endif
+
+
 void luaK_fixline (FuncState *fs, int line) {
+#ifdef LUA_OPTIMIZE_DEBUG
+  /* The fixup line can be the same as existing one and in this case there's nothing to do */
+  if (line != fs->lastline) {
+    /* first remove the current line reference */
+    unsigned char *p = lineInfoTop(fs);
+    lua_assert(*p < 127);
+    if (*p >1) {
+      (*p)--;    /* this is simply decrementing the last count a multi-PC line */
+    } else {
+      /* it's a bit more complicated if it's the 1st instruction on the line */
+      int delta = 0;
+      unsigned char code;
+      /* this logic handles <i/c> [1snnnnnnn [1nnnnnnn]*]? <i/c=1> */
+      *p-- = INFO_FILL_BYTE;
+      /* work backwards over the coded delta computing the delta */
+      while ((code=*p) & INFO_DELTA_MASK) {
+        *p-- = INFO_FILL_BYTE;
+        if (*p & INFO_DELTA_MASK) {
+          delta += ((code & INFO_DELTA_7BITS)<<7);
+        } else {
+          delta += (code & INFO_DELTA_6BITS) + 1;
+          if (code & INFO_SIGN_MASK) delta = -delta;
+        }
+      }
+      /* and reposition the FuncState lastline pointers at the previous instruction count */
+      fs->lastline-= delta + 1;
+      fs->lastlineOffset = p - fs->f->packedlineinfo;
+    }
+    /* Then add the new line reference */
+    generateInfoDeltaLine(fs, line);
+  }
+#else
   fs->f->lineinfo[fs->pc - 1] = line;
+#endif
 }
 
 
@@ -797,9 +884,25 @@ static int luaK_code (FuncState *fs, Instruction i, int line) {
                   MAX_INT, "code size overflow");
   f->code[fs->pc] = i;
   /* save corresponding line information */
+#ifdef LUA_OPTIMIZE_DEBUG
+  /* note that frst time fs->lastline==0 through, so the else branch is taken */
+  if (fs->pc == fs->lineinfoLastPC+1) {
+    if (line == fs->lastline && f->packedlineinfo[fs->lastlineOffset] < INFO_MAX_LINECNT) {
+      f->packedlineinfo[fs->lastlineOffset]++;
+    } else {
+      generateInfoDeltaLine(fs, line);
+    }
+  } else {
+    /* The last instruction is occasionally overwritten as part of branch optimisation*/
+    lua_assert(fs->pc == fs->lineinfoLastPC);  /* panic if its anything other than this !! */
+    luaK_fixline(fs,line);
+  }
+  fs->lineinfoLastPC = fs->pc;
+#else
   luaM_growvector(fs->L, f->lineinfo, fs->pc, f->sizelineinfo, int,
                   MAX_INT, "code size overflow");
   f->lineinfo[fs->pc] = line;
+#endif
   return fs->pc++;
 }
 

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);
+#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;
 }

apps/plugins/lua/ldebug.h

@@ -13,7 +13,19 @@
 
 #define pcRel(pc, p)	(cast(int, (pc) - (p)->code) - 1)
 
-#define getline(f,pc)	(((f)->lineinfo) ? (f)->lineinfo[pc] : 0)
+#ifdef LUA_OPTIMIZE_DEBUG
+#  include "lvm.h"
+#  define getline(f,pc) (((f)->packedlineinfo) ? luaG_getline((f), pc) : 0)
+#  define INFO_FILL_BYTE   0x7F
+#  define INFO_DELTA_MASK  0x80
+#  define INFO_SIGN_MASK   0x40
+#  define INFO_DELTA_6BITS 0x3F
+#  define INFO_DELTA_7BITS 0x7F
+#  define INFO_MAX_LINECNT  126
+#  define lineInfoTop(fs) ((fs)->f->packedlineinfo + (fs)->lastlineOffset)
+#else
+#  define getline(f,pc) (((f)->lineinfo) ? (f)->lineinfo[pc] : 0)
+#endif
 
 #define resethookcount(L)	(L->hookcount = L->basehookcount)
 
@@ -30,4 +42,9 @@ LUAI_FUNC void luaG_errormsg (lua_State *L);
 LUAI_FUNC int luaG_checkcode (const Proto *pt);
 LUAI_FUNC int luaG_checkopenop (Instruction i);
 
+#ifdef LUA_OPTIMIZE_DEBUG
+LUAI_FUNC int luaG_getline (const Proto *f, int pc);
+LUAI_FUNC int luaG_stripdebug (lua_State *L, Proto *f, int level, int recv);
+#endif
+
 #endif

apps/plugins/lua/ldump.c

@@ -113,8 +113,17 @@ static void DumpConstants(const Proto* f, DumpState* D)
 static void DumpDebug(const Proto* f, DumpState* D)
 {
  int i,n;
+#ifdef LUA_OPTIMIZE_DEBUG
+ n = (D->strip || f->packedlineinfo == NULL) ? 0: f->sizelineinfo;
+ DumpInt(n,D);
+ if (n)
+ {
+  DumpBlock(f->packedlineinfo, n, D);
+ }
+#else
  n= (D->strip) ? 0 : f->sizelineinfo;
  DumpVector(f->lineinfo,n,sizeof(int),D);
+#endif
  n= (D->strip) ? 0 : f->sizelocvars;
  DumpInt(n,D);
  for (i=0; i<n; i++)

apps/plugins/lua/lfunc.c

@@ -128,12 +128,17 @@ Proto *luaF_newproto (lua_State *L) {
   f->numparams = 0;
   f->is_vararg = 0;
   f->maxstacksize = 0;
-  f->lineinfo = NULL;
   f->sizelocvars = 0;
   f->locvars = NULL;
   f->linedefined = 0;
   f->lastlinedefined = 0;
   f->source = NULL;
+#ifdef LUA_OPTIMIZE_DEBUG
+  f->packedlineinfo = NULL;
+#else
+  f->lineinfo = NULL;
+
+#endif
   return f;
 }
 
@@ -142,7 +147,13 @@ void luaF_freeproto (lua_State *L, Proto *f) {
   luaM_freearray(L, f->code, f->sizecode, Instruction);
   luaM_freearray(L, f->p, f->sizep, Proto *);
   luaM_freearray(L, f->k, f->sizek, TValue);
+#ifdef LUA_OPTIMIZE_DEBUG
+  if (f->packedlineinfo) {
+    luaM_freearray(L, f->packedlineinfo, f->sizelineinfo, unsigned char);
+  }
+#else
   luaM_freearray(L, f->lineinfo, f->sizelineinfo, int);
+#endif
   luaM_freearray(L, f->locvars, f->sizelocvars, struct LocVar);
   luaM_freearray(L, f->upvalues, f->sizeupvalues, TString *);
   luaM_free(L, f);

apps/plugins/lua/lgc.c

@@ -318,9 +318,13 @@ static l_mem propagatemark (global_State *g) {
       return sizeof(Proto) + sizeof(Instruction) * p->sizecode +
                              sizeof(Proto *) * p->sizep +
                              sizeof(TValue) * p->sizek + 
-                             sizeof(int) * p->sizelineinfo +
                              sizeof(LocVar) * p->sizelocvars +
-                             sizeof(TString *) * p->sizeupvalues;
+                             sizeof(TString *) * p->sizeupvalues +
+#ifdef LUA_OPTIMIZE_DEBUG
+                             p->sizelineinfo;
+#else
+                             sizeof(int) * p->sizelineinfo;
+#endif
     }
     default: lua_assert(0); return 0;
   }

apps/plugins/lua/lobject.h

@@ -240,7 +240,11 @@ typedef struct Proto {
   TValue *k;  /* constants used by the function */
   Instruction *code;
   struct Proto **p;  /* functions defined inside the function */
+#ifdef LUA_OPTIMIZE_DEBUG
+  unsigned char *packedlineinfo;
+#else
   int *lineinfo;  /* map from opcodes to source lines */
+#endif
   struct LocVar *locvars;  /* information about local variables */
   TString **upvalues;  /* upvalue names */
   TString  *source;

apps/plugins/lua/lparser.c

@@ -344,6 +344,11 @@ static void open_func (LexState *ls, FuncState *fs) {
   fs->bl = NULL;
   f->source = ls->source;
   f->maxstacksize = 2;  /* registers 0/1 are always valid */
+#ifdef LUA_OPTIMIZE_DEBUG
+  fs->lastline = 0;
+  fs->lastlineOffset = 0;
+  fs->lineinfoLastPC = -1;
+#endif
   fs->h = luaH_new(L, 0, 0);
   /* anchor table of constants and prototype (to avoid being collected) */
   sethvalue2s(L, L->top, fs->h);
@@ -361,8 +366,14 @@ static void close_func (LexState *ls) {
   luaK_ret(fs, 0, 0);  /* final return */
   luaM_reallocvector(L, f->code, f->sizecode, fs->pc, Instruction);
   f->sizecode = fs->pc;
+#ifdef LUA_OPTIMIZE_DEBUG
+  f->packedlineinfo[fs->lastlineOffset+1]=0;
+  luaM_reallocvector(L, f->packedlineinfo, f->sizelineinfo,
+                     fs->lastlineOffset+2, unsigned char);
+#else
   luaM_reallocvector(L, f->lineinfo, f->sizelineinfo, fs->pc, int);
   f->sizelineinfo = fs->pc;
+#endif
   luaM_reallocvector(L, f->k, f->sizek, fs->nk, TValue);
   f->sizek = fs->nk;
   luaM_reallocvector(L, f->p, f->sizep, fs->np, Proto *);
@@ -379,6 +390,23 @@ static void close_func (LexState *ls) {
   L->top -= 2;  /* remove table and prototype from the stack */
 }
 
+#ifdef LUA_OPTIMIZE_DEBUG
+static void compile_stripdebug(lua_State *L, Proto *f) {
+  int level;
+#ifdef LUA_OPTIMIZE_DEBUG_USER
+  lua_pushlightuserdata(L, &luaG_stripdebug);
+  lua_gettable(L, LUA_REGISTRYINDEX);
+  level = lua_isnil(L, -1) ? LUA_OPTIMIZE_DEBUG : lua_tointeger(L, -1);
+  lua_pop(L, 1);
+#else
+  level = LUA_OPTIMIZE_DEBUG;
+#endif
+
+  if (level > 1) {
+    luaG_stripdebug(L, f, level, 16);
+  }
+}
+#endif
 
 Proto *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff, const char *name) {
   struct LexState lexstate;
@@ -395,6 +423,9 @@ Proto *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff, const char *name) {
   check(&lexstate, TK_EOS);
   close_func(&lexstate);
   L->top--; /* remove 'name' from stack */
+#ifdef LUA_OPTIMIZE_DEBUG
+  compile_stripdebug(L, funcstate.f);
+#endif
   lua_assert(funcstate.prev == NULL);
   lua_assert(funcstate.f->nups == 0);
   lua_assert(lexstate.fs == NULL);
@@ -402,7 +433,6 @@ Proto *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff, const char *name) {
 }
 
 
-
 /*============================================================*/
 /* GRAMMAR RULES */
 /*============================================================*/

apps/plugins/lua/lparser.h

@@ -72,6 +72,11 @@ typedef struct FuncState {
   lu_byte nactvar;  /* number of active local variables */
   upvaldesc upvalues[LUAI_MAXUPVALUES];  /* upvalues */
   unsigned short actvar[LUAI_MAXVARS];  /* declared-variable stack */
+#ifdef LUA_OPTIMIZE_DEBUG
+  int lastline;           /* only used during compilation for line info */
+  int lastlineOffset;     /* ditto */
+  int lineinfoLastPC;     /* ditto */
+#endif
 } FuncState;
 
 

apps/plugins/lua/lua.h

@@ -94,6 +94,9 @@ typedef void * (*lua_Alloc) (void *ud, void *ptr, size_t osize, size_t nsize);
 #include LUA_USER_H
 #endif
 
+#if defined(LUA_OPTIMIZE_DEBUG) && LUA_OPTIMIZE_DEBUG == 0
+#undef LUA_OPTIMIZE_DEBUG
+#endif
 
 /* type of numbers in Lua */
 typedef LUA_NUMBER lua_Number;

apps/plugins/lua/luaconf.h

@@ -818,5 +818,6 @@ extern long rb_pow(long, long);
 /*else*/
 #define LUA_USER_H "lua_user.h"
 #define LUA_DISABLE_BYTECODE
+#define LUA_OPTIMIZE_DEBUG 2 /* Lua Compact Debug -- Terry Ellison 2015 */
 
 #endif

apps/plugins/lua/lundump.c

@@ -140,9 +140,18 @@ static void LoadDebug(LoadState* S, Proto* f)
 {
  int i,n;
  n=LoadInt(S);
+#ifdef LUA_OPTIMIZE_DEBUG
+ if(n) {
+   f->packedlineinfo=luaM_newvector(S->L,n,unsigned char);
+   LoadBlock(S,f->packedlineinfo,n);
+ } else {
+   f->packedlineinfo=NULL;
+ }
+#else
  f->lineinfo=luaM_newvector(S->L,n,int);
  f->sizelineinfo=n;
  LoadVector(S,f->lineinfo,n,sizeof(int));
+#endif
  n=LoadInt(S);
  f->locvars=luaM_newvector(S->L,n,LocVar);
  f->sizelocvars=n;