Support loading of Lua 5.4 bytecode, bump Pluto bytecode version to m…

…ark it as incompatible for older versions

src/lcode.cpp

@@ -1337,7 +1337,7 @@ void luaK_goifnil (FuncState *fs, expdesc *e) {
     discharge2anyreg(fs, e);
     freeexp(fs, e);
     luaK_codeABCk(fs, OP_TESTSET, NO_REG, e->u.reg, NULL_COALESCE, 1);
-    fs->f->onPlutoOpUsed(0);
+    fs->f->lua_vm_compatible = false;
     pc = luaK_jump(fs);  /* jump if nil */
   }
   luaK_concat(fs, &e->t, pc);  /* insert new jump in 't' list */

src/ldump.cpp

@@ -32,7 +32,6 @@ typedef struct {
   Table *h;  /* table to track saved strings */
   lua_Integer nstr;  /* counter to number saved strings */
   bool lua_vm_compatible;
-  lu_byte min_required_version;
 } DumpState;
 
 
@@ -255,7 +254,7 @@ static void dumpHeader (DumpState *D) {
     dumpByte(D, LUAC_FORMAT);
   }
   else {
-    dumpByte(D, D->min_required_version);
+    dumpByte(D, 1);
     dumpByte(D, 'P');
   }
   dumpLiteral(D, LUAC_DATA);
@@ -267,15 +266,14 @@ static void dumpHeader (DumpState *D) {
 }
 
 
-static void check_vm_compatibility (const Proto *f, bool& lua_vm_compatible, lu_byte& min_required_version) {
-  if (!f->lua_vm_compatible) {
-    lua_vm_compatible = false;
-    if (f->min_required_version > min_required_version)
-      min_required_version = f->min_required_version;
-  }
+static bool is_lua_vm_compatible (const Proto *f) {
+  if (!f->lua_vm_compatible)
+    return false;
   for (int i = 0; i != f->sizep; ++i) {
-    check_vm_compatibility(f->p[i], lua_vm_compatible, min_required_version);
+    if (!is_lua_vm_compatible(f->p[i]))
+      return false;
   }
+  return true;
 }
 
 
@@ -295,8 +293,7 @@ int luaU_dump (lua_State *L, const Proto *f, lua_Writer w, void *data,
   D.strip = strip;
   D.status = 0;
   D.nstr = 0;
-  D.lua_vm_compatible = true;
-  check_vm_compatibility(f, D.lua_vm_compatible, D.min_required_version);
+  D.lua_vm_compatible = is_lua_vm_compatible(f);
   dumpHeader(&D);
   dumpByte(&D, f->sizeupvalues);
   dumpFunction(&D, f);

src/lobject.h

@@ -596,14 +596,6 @@ typedef struct Proto {
   TString  *source;  /* used for debug information */
   GCObject *gclist;
   bool lua_vm_compatible;
-  lu_byte min_required_version;
-
-  void onPlutoOpUsed(lu_byte min_required_version) noexcept {
-    if (lua_vm_compatible || min_required_version > this->min_required_version) {
-      lua_vm_compatible = false;
-      this->min_required_version = min_required_version;
-    }
-  }
 } Proto;
 
 /* }================================================================== */

src/lparser.cpp

@@ -3438,7 +3438,7 @@ static void inexpr (LexState *ls, expdesc *v) {
   luaK_dischargevars(ls->fs, &v2);
   luaK_exp2nextreg(ls->fs, &v2);
   luaK_codeABC(ls->fs, OP_IN, v->u.reg, v2.u.reg, 0);
-  ls->fs->f->onPlutoOpUsed(0);
+  ls->fs->f->lua_vm_compatible = false;
   ls->fs->freereg = base + 1;
 }
 

src/lundump.cpp

@@ -20,6 +20,7 @@
 #include "lfunc.h"
 #include "lmem.h"
 #include "lobject.h"
+#include "lopcodes.h" // GET_OPCODE
 #include "lstring.h"
 #include "ltable.h"
 #include "lundump.h"
@@ -39,6 +40,7 @@ typedef struct {
   size_t offset;  /* current position relative to beginning of dump */
   lua_Integer nstr;  /* number of strings in the list */
   lu_byte fixed;  /* dump is fixed in memory */
+  bool lua54;  /* we're loading bytecode generated by Lua 5.4 (Pluto 0.8.x and below) */
 } LoadState;
 
 
@@ -62,6 +64,8 @@ static void loadBlock (LoadState *S, void *b, size_t size) {
 
 
 static void loadAlign (LoadState *S, int align) {
+  if (S->lua54)
+    return;
   int padding = align - (S->offset % align);
   if (padding < align) {  /* apd == align means no padding */
     lua_Integer paddingContent;
@@ -148,17 +152,20 @@ static void loadString (LoadState *S, Proto *p, TString **sl) {
     lua_assert(*sl == NULL);  /* must be prefilled */
     return;
   }
-  else if (size == 1) {  /* previously saved string? */
+  else if (size == 1 && !S->lua54) {  /* previously saved string? */
     int idx = loadInt(S);  /* get its index */
     TValue stv;
     luaH_getint(S->h, idx, &stv);
     *sl = ts = tsvalue(&stv);
     luaC_objbarrier(L, p, ts);
     return;  /* do not save it again */
   }
-  else if ((size -= 2) <= LUAI_MAXSHORTLEN) {  /* short string? */
+  else if ((size -= (S->lua54 ? 1 : 2)) <= LUAI_MAXSHORTLEN) {  /* short string? */
     char buff[LUAI_MAXSHORTLEN + 1];  /* extra space for '\0' */
-    loadVector(S, buff, size + 1);  /* load string into buffer */
+    if (S->lua54)
+      loadVector(S, buff, size);  /* load string into buffer */
+    else
+      loadVector(S, buff, size + 1);  /* load string into buffer */
     *sl = ts = luaS_newlstr(L, buff, size);  /* create string */
     luaC_objbarrier(L, p, ts);
   }
@@ -170,7 +177,9 @@ static void loadString (LoadState *S, Proto *p, TString **sl) {
   else {  /* create internal copy */
     *sl = ts = luaS_createlngstrobj(L, size);  /* create string */
     luaC_objbarrier(L, p, ts);
-    loadVector(S, getlngstr(ts), size + 1);  /* load directly in final place */
+    if (!S->lua54)
+      ++size;
+    loadVector(S, getlngstr(ts), size);  /* load directly in final place */
   }
   /* add string to list of saved strings */
   S->nstr++;
@@ -191,6 +200,12 @@ static void loadCode (LoadState *S, Proto *f) {
     f->code = luaM_newvectorchecked(S->L, n, Instruction);
     f->sizecode = n;
     loadVector(S, f->code, n);
+    if (S->lua54) {
+      for (int i = 0; i != n; ++i) {
+        if (GET_OPCODE(f->code[i]) == OP_FORPREP || GET_OPCODE(f->code[i]) == OP_TFORPREP || GET_OPCODE(f->code[i]) == OP_TFORCALL || GET_OPCODE(f->code[i]) == OP_TFORLOOP)
+          error(S, "incompatible Lua 5.4 instructions");
+      }
+    }
   }
 }
 
@@ -298,7 +313,14 @@ static void loadDebug (LoadState *S, Proto *f) {
     else {
       f->abslineinfo = luaM_newvectorchecked(S->L, n, AbsLineInfo);
       f->sizeabslineinfo = n;
-      loadVector(S, f->abslineinfo, n);
+      if (S->lua54) {
+        for (i = 0; i < n; i++) {
+          f->abslineinfo[i].pc = loadInt(S);
+          f->abslineinfo[i].line = loadInt(S);
+        }
+      }
+      else
+        loadVector(S, f->abslineinfo, n);
     }
   }
   n = loadInt(S);
@@ -320,6 +342,8 @@ static void loadDebug (LoadState *S, Proto *f) {
 
 
 static void loadFunction (LoadState *S, Proto *f) {
+  if (S->lua54)
+    loadString(S, f, &f->source);
   f->linedefined = loadInt(S);
   f->lastlinedefined = loadInt(S);
   f->numparams = loadByte(S);
@@ -331,7 +355,8 @@ static void loadFunction (LoadState *S, Proto *f) {
   loadConstants(S, f);
   loadUpvalues(S, f);
   loadProtos(S, f);
-  loadString(S, f, &f->source);
+  if (!S->lua54)
+    loadString(S, f, &f->source);
   loadDebug(S, f);
 }
 
@@ -358,12 +383,16 @@ static void checkHeader (LoadState *S) {
   checkliteral(S, &LUA_SIGNATURE[1], "not a binary chunk");
   auto version = loadByte(S);
   auto format = loadByte(S);
-  if (format == LUAC_FORMAT) {
-    if (version != LUAC_VERSION)
-     error(S, "version mismatch");
+  if (format == LUAC_FORMAT) {  /* Lua bytecode? (or Lua-compatible Pluto bytecode) */
+    if (version == 0x54)
+      S->lua54 = true;
+    else if (version != LUAC_VERSION)
+      error(S, "version mismatch");
   }
-  else if (format == 'P') {
-    if (version > 0)
+  else if (format == 'P') {  /* Pluto bytecode? */
+    if (version == 0)
+      S->lua54 = true;  /* This was generated by Pluto 0.8.x, which is based on Lua 5.4. */
+    else if (version != 1)
       error(S, "version mismatch");
   }
   else
@@ -395,6 +424,7 @@ LClosure *luaU_undump (lua_State *L, ZIO *Z, const char *name, int fixed) {
   S.Z = Z;
   S.fixed = fixed;
   S.offset = 1;  /* fist byte was already read */
+  S.lua54 = false;
   checkHeader(&S);
   cl = luaF_newLclosure(L, loadByte(&S));
   setclLvalue2s(L, L->top.p, cl);