Lua tidy-up to reduce delta against esp32 branch.

These should hopefully be completely uncontentious changes.

There is still a delta against the esp32 branch, but to harmonise that
requires a bit more work.

This commit includes:

- Some LUA_USE_xxx #ifdef changes, since in many ways the ESP32 is
  closer to a host build than an ESP8266 build.

- A bunch of warnings tidy-ups.

- A couple of readability/maintainability improvements (e.g. LROT_END
  definition using named member initialisation, prototype declarations
  moved to header file(s)).

app/lua/lbaselib.c

@@ -24,7 +24,7 @@
 ** model but changing `fputs' to put the strings at a proper place
 ** (a console window or a log file, for instance).
 */
-#ifdef LUA_CROSS_COMPILER
+#if defined(LUA_USE_ESP8266)
 #undef puts
 #define puts(s) printf("%s",s)
 #endif

app/lua/ldebug.c

@@ -248,6 +248,7 @@ static int stripdebug (lua_State *L, Proto *f, int level) {
         f->packedlineinfo = luaM_freearray(L, f->packedlineinfo, sizepackedlineinfo, unsigned char);
         len += sizepackedlineinfo;
       }
+      // fall-through
     case 1:
       f->locvars = luaM_freearray(L, f->locvars, f->sizelocvars, struct LocVar);
       f->upvalues = luaM_freearray(L, f->upvalues, f->sizeupvalues, TString *);
@@ -501,7 +502,7 @@ static Instruction symbexec (const Proto *pt, int lastpc, int reg) {
       case OP_FORLOOP:
       case OP_FORPREP:
         checkreg(pt, a+3);
-        /* go through */
+        /* fall-through */
       case OP_JMP: {
         int dest = pc+1+b;
         /* not full check and jump is forward and do not skip `lastpc'? */

app/lua/lflash.c

@@ -29,7 +29,7 @@
  * process.
  */
 
-static char    *flashAddr;
+static const char *flashAddr;
 static uint32_t flashSize;
 static uint32_t flashAddrPhys;
 static uint32_t flashSector;
@@ -106,20 +106,20 @@ LUA_API void dumpStrings(lua_State *L) {
  * writes are suppressed if the global writeToFlash is false.  This is used in
  * phase I where the pass is used to size the structures in flash.
  */
-static char *flashPosition(void){
+static const char *flashPosition(void){
   return  flashAddr + curOffset;
 }
 
 
-static char *flashSetPosition(uint32_t offset){
+static const char *flashSetPosition(uint32_t offset){
   NODE_DBG("flashSetPosition(%04x)\n", offset);
   curOffset = offset;
   return flashPosition();
 }
 
 
-static char *flashBlock(const void* b, size_t size)  {
-  void *cur = flashPosition();
+static const char *flashBlock(const void* b, size_t size)  {
+  const void *cur = flashPosition();
   NODE_DBG("flashBlock((%04x),%p,%04x)\n", curOffset,b,size);
   lua_assert(ALIGN_BITS(b) == 0 && ALIGN_BITS(size) == 0);
   platform_flash_write(b, flashAddrPhys+curOffset, size);
@@ -137,6 +137,10 @@ static void flashErase(uint32_t start, uint32_t end){
     platform_flash_erase_sector( flashSector + i );
 }
 
+static int loadLFS (lua_State *L);
+static int loadLFSgc (lua_State *L);
+static void procFirstPass (void);
+
 /* =====================================================================================
  * luaN_init() is exported via lflash.h.
  * The first is the startup hook used in lstate.c and the last two are
@@ -171,7 +175,7 @@ LUAI_FUNC void luaN_init (lua_State *L) {
   }
 
   if ((fh->flash_sig & (~FLASH_SIG_ABSOLUTE)) != FLASH_SIG ) {
-    NODE_ERR("Flash sig not correct: 0x%08x vs 0x%08x\n",
+    NODE_ERR("LFS sig not correct: 0x%x vs expected 0x%x\n",
        fh->flash_sig & (~FLASH_SIG_ABSOLUTE), FLASH_SIG);
     return;
   }
@@ -208,6 +212,7 @@ LUALIB_API void luaL_lfsreload (lua_State *L) {
     return;
   }
 
+
  /*
   * Do a protected call of loadLFS.
   *
@@ -346,13 +351,13 @@ static void put_byte (uint8_t value) {
 }
 
 
-static uint8_t recall_byte (unsigned offset) {
+static uint8_t recall_byte (uint32_t offset) {
   if(offset > DICTIONARY_WINDOW || offset >= out->ndx)
     flash_error("invalid dictionary offset on inflate");
   /* ndx starts at 1. Need relative to 0 */
-  unsigned n   = out->ndx - offset;
-  unsigned pos = n % WRITE_BLOCKSIZE;
-  unsigned blockNo = out->ndx / WRITE_BLOCKSIZE - n  / WRITE_BLOCKSIZE;
+  uint32_t n   = out->ndx - offset;
+  uint32_t pos = n % WRITE_BLOCKSIZE;
+  uint32_t blockNo = out->ndx / WRITE_BLOCKSIZE - n  / WRITE_BLOCKSIZE;
   return out->block[blockNo]->byte[pos];
 }
 
@@ -386,7 +391,7 @@ void procFirstPass (void) {
          fh->flash_size > flashSize ||
          out->flagsLen != 1 + (out->flashLen/WORDSIZE - 1) / BITS_PER_WORD)
       flash_error("LFS length mismatch");
-    out->flags = luaM_newvector(out->L, out->flagsLen, unsigned);
+    out->flags = luaM_newvector(out->L, out->flagsLen, uint32_t);
   }
 
   /* update running CRC */
@@ -412,7 +417,7 @@ void procSecondPass (void) {
                   (out->flashLen % WRITE_BLOCKSIZE) / WORDSIZE :
                   WRITE_BLOCKSIZE / WORDSIZE;
   uint32_t *buf = (uint32_t *) out->buffer.byte;
-  uint32_t  flags = 0;
+  uint32_t flags = 0;
  /*
   * Relocate all the addresses tagged in out->flags.  This can't be done in
   * place because the out->blocks are still in use as dictionary content so
@@ -423,7 +428,7 @@ void procSecondPass (void) {
     if ((i&31)==0)
       flags = out->flags[out->flagsNdx++];
     if (flags&1)
-      buf[i] = WORDSIZE*buf[i] + cast(uint32_t, flashAddr);
+      buf[i] = WORDSIZE*buf[i] + cast(uint32_t, flashAddr); // mapped, not phys
   }
  /*
   * On first block, set the flash_sig has the in progress bit set and this
@@ -468,7 +473,7 @@ static int loadLFS (lua_State *L) {
   in->len = vfs_size(in->fd);
   if (in->len <= 200 ||        /* size of an empty luac output */
       vfs_lseek(in->fd, in->len-4, VFS_SEEK_SET) != in->len-4 ||
-      vfs_read(in->fd, &out->len, sizeof(unsigned)) != sizeof(unsigned))
+      vfs_read(in->fd, &out->len, sizeof(uint32_t)) != sizeof(uint32_t))
     flash_error("read error on LFS image file");
   vfs_lseek(in->fd, 0, VFS_SEEK_SET);
 

app/lua/llex.c

@@ -61,6 +61,7 @@ static void save (LexState *ls, int c) {
 
 
 void luaX_init (lua_State *L) {
+  (void)L;
 }
 
 

app/lua/lmathlib.c

@@ -359,5 +359,6 @@ LROT_END(math, NULL, 0)
 ** Open math library
 */
 LUALIB_API int luaopen_math (lua_State *L) {
+  (void)L;
   return 0;
 }

app/lua/lnodemcu.c

@@ -118,6 +118,7 @@ LUALIB_API int luaL_posttask( lua_State* L, int prio ) {          // [-1, +0, -]
 }
 #else
 LUALIB_API int luaL_posttask( lua_State* L, int prio ) { 
+  (void)L; (void)prio;
   return 0;
 } /* Dummy stub on host */
 #endif

app/lua/lnodemcu.h

@@ -45,9 +45,11 @@
   static ROTable_entry LOCK_IN_SECTION(s) rt ## _entries[] = {
 #define LROT_END(rt,mt,f)    {NULL, LRO_NILVAL} }; \
   const ROTable rt ## _ROTable = { \
-    (GCObject *)1, LUA_TROTABLE, LROT_MARKED, \
-    cast(lu_byte, ~(f)), (sizeof(rt ## _entries)/sizeof(ROTable_entry)) - 1, \
-    cast(Table *, mt), cast(ROTable_entry *, rt ## _entries) };
+    .next = (GCObject *)1, .tt = LUA_TROTABLE, .marked = LROT_MARKED, \
+    .flags = cast(lu_byte, ~(f)), \
+    .lsizenode = (sizeof(rt ## _entries)/sizeof(ROTable_entry)) - 1, \
+    .metatable = cast(Table *, mt), \
+    .entry = cast(ROTable_entry *, rt ## _entries) };
 #define LROT_BREAK(rt)       };
 
 #define LROT_MASK(m)         cast(lu_byte, 1<<TM_ ## m)
@@ -65,10 +67,9 @@
 #define LROT_MASK_NEWINDEX   LROT_MASK(NEWINDEX)
 #define LROT_MASK_GC_INDEX   (LROT_MASK_GC | LROT_MASK_INDEX)
 
-/* Maximum length of a rotable name and of a string key*/
+#define LUA_MAX_ROTABLE_NAME 32  /* Maximum length of a rotable name and of a string key*/
 
 #ifdef LUA_CORE
 
 #endif
 #endif
-

app/lua/loadlib.c

@@ -619,6 +619,7 @@ static int ll_seeall (lua_State *L) {
 
 static void setpath (lua_State *L, const char *fieldname, const char *envname,
                                    const char *def) {
+  (void)envname;
   const char *path = NULL;  /* getenv(envname) not used in NodeMCU */;
   if (path == NULL)  /* no environment variable? */
     lua_pushstring(L, def);  /* use default */

app/lua/lobject.c

@@ -68,10 +68,7 @@ int luaO_log2 (unsigned int x) {
   while (x >= 256) { l += 8; x >>= 8; }
   return l + log_2[x];
 #else
- /* Use Normalization Shift Amount Unsigned:  0x1=>31 up to 0xffffffff =>0
-  * See Xtensa Instruction Set Architecture (ISA) Refman  P 462 */
-  asm volatile ("nsau %0, %1;" :"=r"(x) : "r"(x));
-  return 31 - x;
+  return 31 - __builtin_clz(x);
 #endif
 }
 

app/lua/lobject.h

@@ -28,7 +28,7 @@
 #define LUA_TUPVAL	(LAST_TAG+2)
 #define LUA_TDEADKEY	(LAST_TAG+3)
 
-#ifdef LUA_USE_ESP
+#ifdef LUA_USE_ESP8266
 /*
 ** force aligned access to critical fields in Flash-based structures
 ** wo is the offset of aligned word in bytes 0,4,8,..

app/lua/ltable.c

@@ -336,6 +336,7 @@ static Node *find_prev_node(Node *mp, Node *next) {
 ** (colliding node is in its main position), moving node goes to an empty position.
 */
 static int move_node (lua_State *L, Table *t, Node *node) {
+  (void)L;
   Node *mp = mainposition(t, key2tval(node));
   /* if node is in it's main position, don't need to move node. */
   if (mp == node) return 1;
@@ -374,6 +375,7 @@ static int move_node (lua_State *L, Table *t, Node *node) {
 
 
 static int move_number (lua_State *L, Table *t, Node *node) {
+  (void)L;
   int key;
   lua_Number n = nvalue(key2tval(node));
   lua_number2int(key, n);

app/lua/ltablib.c

@@ -277,5 +277,6 @@ LROT_BEGIN(tab_funcs, NULL, 0)
 LROT_END(tab_funcs, NULL, 0)
 
 LUALIB_API int luaopen_table (lua_State *L) {
+  (void)L;
   return 1;
 }

app/lua/lundump.c

@@ -145,7 +145,7 @@ static lua_Number LoadNumber(LoadState* S)
     LoadVar(S,y);
     x = (lua_Number)y;
    } break;
-   default: lua_assert(0);
+   default: lua_assert(0); __builtin_unreachable();
   }
  }
  else

app/lua53/lauxlib.h

@@ -144,6 +144,9 @@ LUALIB_API void (luaL_requiref) (lua_State *L, const char *modname,
 #define luaL_loadbuffer(L,s,sz,n)	luaL_loadbufferx(L,s,sz,n,NULL)
 
 
+#define luaL_checkfunction(L,n)        luaL_checktype(L, (n), LUA_TFUNCTION);
+#define luaL_checktable(L,n)   luaL_checktype(L, (n), LUA_TTABLE);
+
 /*
 ** {======================================================
 ** Generic Buffer manipulation
@@ -227,7 +230,8 @@ LUALIB_API void (luaL_openlib) (lua_State *L, const char *libname,
 
 /* print a string */
 #if !defined(lua_writestring)
-#ifdef LUA_USE_ESP8266
+#ifdef LUA_USE_ESP
+void output_redirect(const char *str, size_t l);
 #define lua_writestring(s,l)  output_redirect((s),(l))
 #else
 #define lua_writestring(s,l)   fwrite((s), sizeof(char), (l), stdout)
@@ -290,11 +294,8 @@ LUALIB_API int  (luaL_pushlfsdts) (lua_State *L);
 LUALIB_API void (luaL_lfsreload) (lua_State *L);
 LUALIB_API int  (luaL_posttask) (lua_State* L, int prio);
 LUALIB_API int  (luaL_pcallx) (lua_State *L, int narg, int nres);
-
 #define luaL_pushlfsmodule(l) lua_pushlfsfunc(L)
 
 /* }============================================================ */
 
 #endif
-
-

app/lua53/ldblib.c

@@ -464,6 +464,7 @@ LROT_BEGIN(dblib, NULL, 0)
 LROT_END(dblib, NULL, 0)
 
 LUAMOD_API int luaopen_debug (lua_State *L) {
+  (void)L;
   return 0;
 }
 

app/lua53/ldump.c

@@ -272,6 +272,7 @@ static int stripdebug (lua_State *L, Proto *f, int level) {
         f->lineinfo = luaM_freearray(L, f->lineinfo, f->sizelineinfo);
         len += f->sizelineinfo;
       }
+      // fall-through
     case 1:
       for (i=0; i<f->sizeupvalues; i++)
         f->upvalues[i].name = NULL;

app/lua53/lmathlib.c

@@ -394,6 +394,7 @@ LROT_END(mathlib, NULL, 0)
 ** Open math library
 */
 LUAMOD_API int luaopen_math (lua_State *L) {
+  (void)L;
   return 0;
 }