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Add the OP_SetTabCol and OP_VerifyTabCol opcodes, only when compiling with

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SQLITE_DEBUG, to do run-time verification of the column cache.

FossilOrigin-Name: b37614a3670770919a7c7f8157c5fd6578d736447998640b52e5cef8174cadc2
This commit is contained in:
drh
2018-06-11 17:35:02 +00:00
parent 8d7b212c4c
commit 299bf7c2f0
10 changed files with 123 additions and 18 deletions
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40
src/vdbe.c
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@@ -36,6 +36,18 @@
# define memAboutToChange(P,M)
#endif
/*
** Given a cursor number and a column for a table or index, compute a
** hash value for use in the Mem.iTabColHash value. The iTabColHash
** column is only used for verification - it is omitted from production
** builds. Collisions are harmless in the sense that the correct answer
** still results. The only harm of collisions is that they can potential
** reduce column-cache error detection during SQLITE_DEBUG builds.
**
** No valid hash should be 0.
*/
#define TableColumnHash(T,C) (((u32)(T)<<16)^(u32)(C+2))
/*
** The following global variable is incremented every time a cursor
** moves, either by the OP_SeekXX, OP_Next, or OP_Prev opcodes. The test
@@ -7318,6 +7330,34 @@ case OP_Abortable: {
}
#endif
#ifdef SQLITE_DEBUG_COLUMNCACHE
/* Opcode: SetTabCol P1 P2 P3 * *
**
** Set a flag in register REG[P3] indicating that it holds the value
** of column P2 from the table on cursor P1. This flag is checked
** by a subsequent VerifyTabCol opcode.
**
** This opcode only appears SQLITE_DEBUG builds. It is used to verify
** that the expression table column cache is working correctly.
*/
case OP_SetTabCol: {
aMem[pOp->p3].iTabColHash = TableColumnHash(pOp->p1,pOp->p2);
break;
}
/* Opcode: VerifyTabCol P1 P2 P3 * *
**
** Verify that register REG[P3] contains the value of column P2 from
** cursor P1. Assert() if this is not the case.
**
** This opcode only appears SQLITE_DEBUG builds. It is used to verify
** that the expression table column cache is working correctly.
*/
case OP_VerifyTabCol: {
assert( aMem[pOp->p3].iTabColHash == TableColumnHash(pOp->p1,pOp->p2) );
break;
}
#endif
/* Opcode: Noop * * * * *
**
** Do nothing. This instruction is often useful as a jump