Free up the MEM_Frame bit in Mem.flags object. Store VdbeFrame objects

as MEM_Blob with a special Mem.xDel pointer instead.

FossilOrigin-Name: 62db5fd47660bbc4fcf2c6d4a6c5a3077f12c6442a128d22b66b789a0409ef32

src/vdbe.c

@@ -6050,7 +6050,7 @@ case OP_Program: {        /* jump */
   ** of the current program, and the memory required at runtime to execute
   ** the trigger program. If this trigger has been fired before, then pRt 
   ** is already allocated. Otherwise, it must be initialized.  */
-  if( (pRt->flags&MEM_Frame)==0 ){
+  if( (pRt->flags&MEM_Blob)==0 ){
     /* SubProgram.nMem is set to the number of memory cells used by the 
     ** program stored in SubProgram.aOp. As well as these, one memory
     ** cell is required for each cursor used by the program. Set local
@@ -6068,8 +6068,10 @@ case OP_Program: {        /* jump */
       goto no_mem;
     }
     sqlite3VdbeMemRelease(pRt);
-    pRt->flags = MEM_Frame;
-    pRt->u.pFrame = pFrame;
+    pRt->flags = MEM_Blob|MEM_Dyn;
+    pRt->z = (char*)pFrame;
+    pRt->n = nByte;
+    pRt->xDel = sqlite3VdbeFrameMemDel;
 
     pFrame->v = p;
     pFrame->nChildMem = nMem;
@@ -6085,6 +6087,9 @@ case OP_Program: {        /* jump */
 #ifdef SQLITE_ENABLE_STMT_SCANSTATUS
     pFrame->anExec = p->anExec;
 #endif
+#ifdef SQLITE_DEBUG
+    pFrame->iFrameMagic = SQLITE_FRAME_MAGIC;
+#endif
 
     pEnd = &VdbeFrameMem(pFrame)[pFrame->nChildMem];
     for(pMem=VdbeFrameMem(pFrame); pMem!=pEnd; pMem++){
@@ -6092,7 +6097,8 @@ case OP_Program: {        /* jump */
       pMem->db = db;
     }
   }else{
-    pFrame = pRt->u.pFrame;
+    pFrame = (VdbeFrame*)pRt->z;
+    assert( pRt->xDel==sqlite3VdbeFrameMemDel );
     assert( pProgram->nMem+pProgram->nCsr==pFrame->nChildMem 
         || (pProgram->nCsr==0 && pProgram->nMem+1==pFrame->nChildMem) );
     assert( pProgram->nCsr==pFrame->nChildCsr );

src/vdbeInt.h

@@ -169,6 +169,9 @@ struct VdbeFrame {
   void *token;            /* Copy of SubProgram.token */
   i64 lastRowid;          /* Last insert rowid (sqlite3.lastRowid) */
   AuxData *pAuxData;      /* Linked list of auxdata allocations */
+#if SQLITE_DEBUG
+  u32 iFrameMagic;        /* magic number for sanity checking */
+#endif
   int nCursor;            /* Number of entries in apCsr */
   int pc;                 /* Program Counter in parent (calling) frame */
   int nOp;                /* Size of aOp array */
@@ -179,6 +182,13 @@ struct VdbeFrame {
   int nDbChange;          /* Value of db->nChange */
 };
 
+/* Magic number for sanity checking on VdbeFrame objects */
+#define SQLITE_FRAME_MAGIC 0x879fb71e
+
+/*
+** Return a pointer to the array of registers allocated for use
+** by a VdbeFrame.
+*/
 #define VdbeFrameMem(p) ((Mem *)&((u8 *)p)[ROUND8(sizeof(VdbeFrame))])
 
 /*
@@ -194,7 +204,6 @@ struct sqlite3_value {
     const char *zPType; /* Pointer type when MEM_Term|MEM_Subtype|MEM_Null */
     FuncDef *pDef;      /* Used only when flags==MEM_Agg */
     RowSet *pRowSet;    /* Used only when flags==MEM_RowSet */
-    VdbeFrame *pFrame;  /* Used when flags==MEM_Frame */
   } u;
   u16 flags;          /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */
   u8  enc;            /* SQLITE_UTF8, SQLITE_UTF16BE, SQLITE_UTF16LE */
@@ -239,7 +248,7 @@ struct sqlite3_value {
 #define MEM_Blob      0x0010   /* Value is a BLOB */
 #define MEM_AffMask   0x001f   /* Mask of affinity bits */
 #define MEM_RowSet    0x0020   /* Value is a RowSet object */
-#define MEM_Frame     0x0040   /* Value is a VdbeFrame object */
+/* Available          0x0040   */
 #define MEM_Undefined 0x0080   /* Value is undefined */
 #define MEM_Cleared   0x0100   /* NULL set by OP_Null, not from data */
 #define MEM_TypeMask  0xc1ff   /* Mask of type bits */
@@ -266,7 +275,7 @@ struct sqlite3_value {
 ** that needs to be deallocated to avoid a leak.
 */
 #define VdbeMemDynamic(X)  \
-  (((X)->flags&(MEM_Agg|MEM_Dyn|MEM_RowSet|MEM_Frame))!=0)
+  (((X)->flags&(MEM_Agg|MEM_Dyn|MEM_RowSet))!=0)
 
 /*
 ** Clear any existing type flags from a Mem and replace them with f
@@ -500,7 +509,11 @@ const char *sqlite3OpcodeName(int);
 int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve);
 int sqlite3VdbeMemClearAndResize(Mem *pMem, int n);
 int sqlite3VdbeCloseStatement(Vdbe *, int);
-void sqlite3VdbeFrameDelete(VdbeFrame*);
+#ifdef SQLITE_DEBUG
+int sqlite3VdbeFrameIsValid(VdbeFrame*);
+#endif
+void sqlite3VdbeFrameMemDel(void*);      /* Destructor on Mem */
+void sqlite3VdbeFrameDelete(VdbeFrame*); /* Actually deletes the Frame */
 int sqlite3VdbeFrameRestore(VdbeFrame *);
 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
 void sqlite3VdbePreUpdateHook(Vdbe*,VdbeCursor*,int,const char*,Table*,i64,int);

src/vdbeaux.c

@@ -1661,9 +1661,9 @@ static void releaseMemArray(Mem *p, int N){
       */
       testcase( p->flags & MEM_Agg );
       testcase( p->flags & MEM_Dyn );
-      testcase( p->flags & MEM_Frame );
+      testcase( p->xDel==sqlite3VdbeFrameMemDel );
       testcase( p->flags & MEM_RowSet );
-      if( p->flags&(MEM_Agg|MEM_Dyn|MEM_Frame|MEM_RowSet) ){
+      if( p->flags&(MEM_Agg|MEM_Dyn|MEM_RowSet) ){
         sqlite3VdbeMemRelease(p);
       }else if( p->szMalloc ){
         sqlite3DbFreeNN(db, p->zMalloc);
@@ -1675,6 +1675,35 @@ static void releaseMemArray(Mem *p, int N){
   }
 }
 
+#ifdef SQLITE_DEBUG
+/*
+** Verify that pFrame is a valid VdbeFrame pointer.  Return true if it is
+** and false if something is wrong.
+**
+** This routine is intended for use inside of assert() statements only.
+*/
+int sqlite3VdbeFrameIsValid(VdbeFrame *pFrame){
+  if( pFrame->iFrameMagic!=SQLITE_FRAME_MAGIC ) return 0;
+  return 1;
+}
+#endif
+
+
+/*
+** This is a destructor on a Mem object (which is really an sqlite3_value)
+** that deletes the Frame object that is attached to it as a blob.
+**
+** This routine does not delete the Frame right away.  It merely adds the
+** frame to a list of frames to be deleted when the Vdbe halts.
+*/
+void sqlite3VdbeFrameMemDel(void *pArg){
+  VdbeFrame *pFrame = (VdbeFrame*)pArg;
+  assert( sqlite3VdbeFrameIsValid(pFrame) );
+  pFrame->pParent = pFrame->v->pDelFrame;
+  pFrame->v->pDelFrame = pFrame;
+}
+
+
 /*
 ** Delete a VdbeFrame object and its contents. VdbeFrame objects are
 ** allocated by the OP_Program opcode in sqlite3VdbeExec().
@@ -1683,6 +1712,7 @@ void sqlite3VdbeFrameDelete(VdbeFrame *p){
   int i;
   Mem *aMem = VdbeFrameMem(p);
   VdbeCursor **apCsr = (VdbeCursor **)&aMem[p->nChildMem];
+  assert( sqlite3VdbeFrameIsValid(p) );
   for(i=0; i<p->nChildCsr; i++){
     sqlite3VdbeFreeCursor(p->v, apCsr[i]);
   }

src/vdbemem.c

@@ -43,7 +43,7 @@ int sqlite3VdbeCheckMemInvariants(Mem *p){
   if( p->flags & MEM_Null ){
     /* Cannot be both MEM_Null and some other type */
     assert( (p->flags & (MEM_Int|MEM_Real|MEM_Str|MEM_Blob
-                         |MEM_RowSet|MEM_Frame|MEM_Agg))==0 );
+                         |MEM_RowSet|MEM_Agg))==0 );
 
     /* If MEM_Null is set, then either the value is a pure NULL (the usual
     ** case) or it is a pointer set using sqlite3_bind_pointer() or
@@ -467,10 +467,6 @@ static SQLITE_NOINLINE void vdbeMemClearExternAndSetNull(Mem *p){
     p->xDel((void *)p->z);
   }else if( p->flags&MEM_RowSet ){
     sqlite3RowSetClear(p->u.pRowSet);
-  }else if( p->flags&MEM_Frame ){
-    VdbeFrame *pFrame = p->u.pFrame;
-    pFrame->pParent = pFrame->v->pDelFrame;
-    pFrame->v->pDelFrame = pFrame;
   }
   p->flags = MEM_Null;
 }