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Overview
Comment: | Improved comments on VDBE opcodes, for better documentation. No code or logic changes. |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA1: |
2d32e4876e0b162730f81e5c2658be12 |
User & Date: | drh 2014-07-25 18:37:42.754 |
Context
2014-07-25
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21:35 | Try to fix harmless compiler warnings reported by Fortify. (check-in: e0fa6fdc14 user: drh tags: trunk) | |
18:37 | Improved comments on VDBE opcodes, for better documentation. No code or logic changes. (check-in: 2d32e4876e user: drh tags: trunk) | |
18:01 | Add constraints (enforced only when SQLITE_DEBUG is enabled) on the use of OP_Next and OP_Prev. (check-in: 2230c74f1e user: drh tags: trunk) | |
Changes
Changes to src/vdbe.c.
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763 764 765 766 767 768 769 | pc = (int)pIn1->u.i; pIn1->flags = MEM_Undefined; break; } /* Opcode: InitCoroutine P1 P2 P3 * * ** | | | | > > | | > > | > > | > > | > | | 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 | pc = (int)pIn1->u.i; pIn1->flags = MEM_Undefined; break; } /* Opcode: InitCoroutine P1 P2 P3 * * ** ** Set up register P1 so that it will Yield to the coroutine ** located at address P3. ** ** If P2!=0 then the coroutine implementation immediately follows ** this opcode. So jump over the coroutine implementation to ** address P2. ** ** See also: EndCoroutine */ case OP_InitCoroutine: { /* jump */ assert( pOp->p1>0 && pOp->p1<=(p->nMem-p->nCursor) ); assert( pOp->p2>=0 && pOp->p2<p->nOp ); assert( pOp->p3>=0 && pOp->p3<p->nOp ); pOut = &aMem[pOp->p1]; assert( !VdbeMemDynamic(pOut) ); pOut->u.i = pOp->p3 - 1; pOut->flags = MEM_Int; if( pOp->p2 ) pc = pOp->p2 - 1; break; } /* Opcode: EndCoroutine P1 * * * * ** ** The instruction at the address in register P1 is an Yield. ** Jump to the P2 parameter of that Yield. ** After the jump, register P1 becomes undefined. ** ** See also: InitCoroutine */ case OP_EndCoroutine: { /* in1 */ VdbeOp *pCaller; pIn1 = &aMem[pOp->p1]; assert( pIn1->flags==MEM_Int ); assert( pIn1->u.i>=0 && pIn1->u.i<p->nOp ); pCaller = &aOp[pIn1->u.i]; assert( pCaller->opcode==OP_Yield ); assert( pCaller->p2>=0 && pCaller->p2<p->nOp ); pc = pCaller->p2 - 1; pIn1->flags = MEM_Undefined; break; } /* Opcode: Yield P1 P2 * * * ** ** Swap the program counter with the value in register P1. This ** has the effect of yielding to a coroutine. ** ** If the coroutine that is launched by this instruction ends with ** Yield or Return then continue to the next instruction. But if ** the coroutine launched by this instruction ends with ** EndCoroutine, then jump to P2 rather than continuing with the ** next instruction. ** ** See also: InitCoroutine */ case OP_Yield: { /* in1, jump */ int pcDest; pIn1 = &aMem[pOp->p1]; assert( VdbeMemDynamic(pIn1)==0 ); pIn1->flags = MEM_Int; pcDest = (int)pIn1->u.i; |
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2192 2193 2194 2195 2196 2197 2198 | sqlite3VdbeMemSetInt64(pOut, ~sqlite3VdbeIntValue(pIn1)); } break; } /* Opcode: Once P1 P2 * * * ** | | | | | > > > > | 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 | sqlite3VdbeMemSetInt64(pOut, ~sqlite3VdbeIntValue(pIn1)); } break; } /* Opcode: Once P1 P2 * * * ** ** Check the "once" flag number P1. If it is set, jump to instruction P2. ** Otherwise, set the flag and fall through to the next instruction. ** In other words, this opcode causes all following opcodes up through P2 ** (but not including P2) to run just once and to be skipped on subsequent ** times through the loop. ** ** All "once" flags are initially cleared whenever a prepared statement ** first begins to run. */ case OP_Once: { /* jump */ assert( pOp->p1<p->nOnceFlag ); VdbeBranchTaken(p->aOnceFlag[pOp->p1]!=0, 2); if( p->aOnceFlag[pOp->p1] ){ pc = pOp->p2-1; }else{ |
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3491 3492 3493 3494 3495 3496 3497 | ** ** Reposition cursor P1 so that it points to the smallest entry that ** is greater than or equal to the key value. If there are no records ** greater than or equal to the key and P2 is not zero, then jump to P2. ** ** This opcode leaves the cursor configured to move in forward order, ** from the begining toward the end. In other words, the cursor is | | | | | | 3504 3505 3506 3507 3508 3509 3510 3511 3512 3513 3514 3515 3516 3517 3518 3519 3520 3521 3522 3523 3524 3525 3526 3527 3528 3529 3530 3531 3532 3533 3534 3535 3536 3537 3538 3539 3540 3541 3542 3543 3544 3545 3546 3547 3548 3549 3550 3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564 3565 3566 3567 3568 3569 3570 3571 3572 | ** ** Reposition cursor P1 so that it points to the smallest entry that ** is greater than or equal to the key value. If there are no records ** greater than or equal to the key and P2 is not zero, then jump to P2. ** ** This opcode leaves the cursor configured to move in forward order, ** from the begining toward the end. In other words, the cursor is ** configured to use Next, not Prev. ** ** See also: Found, NotFound, SeekLt, SeekGt, SeekLe */ /* Opcode: SeekGT P1 P2 P3 P4 * ** Synopsis: key=r[P3@P4] ** ** If cursor P1 refers to an SQL table (B-Tree that uses integer keys), ** use the value in register P3 as a key. If cursor P1 refers ** to an SQL index, then P3 is the first in an array of P4 registers ** that are used as an unpacked index key. ** ** Reposition cursor P1 so that it points to the smallest entry that ** is greater than the key value. If there are no records greater than ** the key and P2 is not zero, then jump to P2. ** ** This opcode leaves the cursor configured to move in forward order, ** from the begining toward the end. In other words, the cursor is ** configured to use Next, not Prev. ** ** See also: Found, NotFound, SeekLt, SeekGe, SeekLe */ /* Opcode: SeekLT P1 P2 P3 P4 * ** Synopsis: key=r[P3@P4] ** ** If cursor P1 refers to an SQL table (B-Tree that uses integer keys), ** use the value in register P3 as a key. If cursor P1 refers ** to an SQL index, then P3 is the first in an array of P4 registers ** that are used as an unpacked index key. ** ** Reposition cursor P1 so that it points to the largest entry that ** is less than the key value. If there are no records less than ** the key and P2 is not zero, then jump to P2. ** ** This opcode leaves the cursor configured to move in reverse order, ** from the end toward the beginning. In other words, the cursor is ** configured to use Prev, not Next. ** ** See also: Found, NotFound, SeekGt, SeekGe, SeekLe */ /* Opcode: SeekLE P1 P2 P3 P4 * ** Synopsis: key=r[P3@P4] ** ** If cursor P1 refers to an SQL table (B-Tree that uses integer keys), ** use the value in register P3 as a key. If cursor P1 refers ** to an SQL index, then P3 is the first in an array of P4 registers ** that are used as an unpacked index key. ** ** Reposition cursor P1 so that it points to the largest entry that ** is less than or equal to the key value. If there are no records ** less than or equal to the key and P2 is not zero, then jump to P2. ** ** This opcode leaves the cursor configured to move in reverse order, ** from the end toward the beginning. In other words, the cursor is ** configured to use Prev, not Next. ** ** See also: Found, NotFound, SeekGt, SeekGe, SeekLt */ case OP_SeekLT: /* jump, in3 */ case OP_SeekLE: /* jump, in3 */ case OP_SeekGE: /* jump, in3 */ case OP_SeekGT: { /* jump, in3 */ |
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4466 4467 4468 4469 4470 4471 4472 | ** will refer to the last entry in the database table or index. ** If the table or index is empty and P2>0, then jump immediately to P2. ** If P2 is 0 or if the table or index is not empty, fall through ** to the following instruction. ** ** This opcode leaves the cursor configured to move in reverse order, ** from the end toward the beginning. In other words, the cursor is | | | 4479 4480 4481 4482 4483 4484 4485 4486 4487 4488 4489 4490 4491 4492 4493 | ** will refer to the last entry in the database table or index. ** If the table or index is empty and P2>0, then jump immediately to P2. ** If P2 is 0 or if the table or index is not empty, fall through ** to the following instruction. ** ** This opcode leaves the cursor configured to move in reverse order, ** from the end toward the beginning. In other words, the cursor is ** configured to use Prev, not Next. */ case OP_Last: { /* jump */ VdbeCursor *pC; BtCursor *pCrsr; int res; assert( pOp->p1>=0 && pOp->p1<p->nCursor ); |
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4526 4527 4528 4529 4530 4531 4532 | ** will refer to the first entry in the database table or index. ** If the table or index is empty and P2>0, then jump immediately to P2. ** If P2 is 0 or if the table or index is not empty, fall through ** to the following instruction. ** ** This opcode leaves the cursor configured to move in forward order, ** from the begining toward the end. In other words, the cursor is | | | 4539 4540 4541 4542 4543 4544 4545 4546 4547 4548 4549 4550 4551 4552 4553 | ** will refer to the first entry in the database table or index. ** If the table or index is empty and P2>0, then jump immediately to P2. ** If P2 is 0 or if the table or index is not empty, fall through ** to the following instruction. ** ** This opcode leaves the cursor configured to move in forward order, ** from the begining toward the end. In other words, the cursor is ** configured to use Next, not Prev. */ case OP_Rewind: { /* jump */ VdbeCursor *pC; BtCursor *pCrsr; int res; assert( pOp->p1>=0 && pOp->p1<p->nCursor ); |
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4567 4568 4569 4570 4571 4572 4573 | /* Opcode: Next P1 P2 P3 P4 P5 ** ** Advance cursor P1 so that it points to the next key/data pair in its ** table or index. If there are no more key/value pairs then fall through ** to the following instruction. But if the cursor advance was successful, ** jump immediately to P2. ** | | | | | | | | | | 4580 4581 4582 4583 4584 4585 4586 4587 4588 4589 4590 4591 4592 4593 4594 4595 4596 4597 4598 4599 4600 4601 4602 4603 4604 4605 4606 4607 4608 4609 4610 4611 4612 4613 4614 4615 4616 4617 4618 4619 4620 4621 4622 4623 4624 4625 4626 4627 4628 4629 4630 4631 4632 4633 4634 4635 4636 4637 4638 4639 4640 4641 4642 4643 4644 4645 4646 4647 | /* Opcode: Next P1 P2 P3 P4 P5 ** ** Advance cursor P1 so that it points to the next key/data pair in its ** table or index. If there are no more key/value pairs then fall through ** to the following instruction. But if the cursor advance was successful, ** jump immediately to P2. ** ** The Next opcode is only valid following an SeekGT, SeekGE, or ** OP_Rewind opcode used to position the cursor. Next is not allowed ** to follow SeekLT, SeekLE, or OP_Last. ** ** The P1 cursor must be for a real table, not a pseudo-table. P1 must have ** been opened prior to this opcode or the program will segfault. ** ** The P3 value is a hint to the btree implementation. If P3==1, that ** means P1 is an SQL index and that this instruction could have been ** omitted if that index had been unique. P3 is usually 0. P3 is ** always either 0 or 1. ** ** P4 is always of type P4_ADVANCE. The function pointer points to ** sqlite3BtreeNext(). ** ** If P5 is positive and the jump is taken, then event counter ** number P5-1 in the prepared statement is incremented. ** ** See also: Prev, NextIfOpen */ /* Opcode: NextIfOpen P1 P2 P3 P4 P5 ** ** This opcode works just like Next except that if cursor P1 is not ** open it behaves a no-op. */ /* Opcode: Prev P1 P2 P3 P4 P5 ** ** Back up cursor P1 so that it points to the previous key/data pair in its ** table or index. If there is no previous key/value pairs then fall through ** to the following instruction. But if the cursor backup was successful, ** jump immediately to P2. ** ** ** The Prev opcode is only valid following an SeekLT, SeekLE, or ** OP_Last opcode used to position the cursor. Prev is not allowed ** to follow SeekGT, SeekGE, or OP_Rewind. ** ** The P1 cursor must be for a real table, not a pseudo-table. If P1 is ** not open then the behavior is undefined. ** ** The P3 value is a hint to the btree implementation. If P3==1, that ** means P1 is an SQL index and that this instruction could have been ** omitted if that index had been unique. P3 is usually 0. P3 is ** always either 0 or 1. ** ** P4 is always of type P4_ADVANCE. The function pointer points to ** sqlite3BtreePrevious(). ** ** If P5 is positive and the jump is taken, then event counter ** number P5-1 in the prepared statement is incremented. */ /* Opcode: PrevIfOpen P1 P2 P3 P4 P5 ** ** This opcode works just like Prev except that if cursor P1 is not ** open it behaves a no-op. */ case OP_SorterNext: { /* jump */ VdbeCursor *pC; int res; pC = p->apCsr[pOp->p1]; |
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5141 5142 5143 5144 5145 5146 5147 | } #endif /* !defined(SQLITE_OMIT_ANALYZE) */ /* Opcode: DropTable P1 * * P4 * ** ** Remove the internal (in-memory) data structures that describe ** the table named P4 in database P1. This is called after a table | > | > | > | | 5154 5155 5156 5157 5158 5159 5160 5161 5162 5163 5164 5165 5166 5167 5168 5169 5170 5171 5172 5173 5174 5175 5176 5177 5178 5179 5180 5181 5182 5183 5184 5185 5186 5187 5188 5189 5190 5191 5192 5193 5194 5195 | } #endif /* !defined(SQLITE_OMIT_ANALYZE) */ /* Opcode: DropTable P1 * * P4 * ** ** Remove the internal (in-memory) data structures that describe ** the table named P4 in database P1. This is called after a table ** is dropped from disk (using the Destroy opcode) in order to keep ** the internal representation of the ** schema consistent with what is on disk. */ case OP_DropTable: { sqlite3UnlinkAndDeleteTable(db, pOp->p1, pOp->p4.z); break; } /* Opcode: DropIndex P1 * * P4 * ** ** Remove the internal (in-memory) data structures that describe ** the index named P4 in database P1. This is called after an index ** is dropped from disk (using the Destroy opcode) ** in order to keep the internal representation of the ** schema consistent with what is on disk. */ case OP_DropIndex: { sqlite3UnlinkAndDeleteIndex(db, pOp->p1, pOp->p4.z); break; } /* Opcode: DropTrigger P1 * * P4 * ** ** Remove the internal (in-memory) data structures that describe ** the trigger named P4 in database P1. This is called after a trigger ** is dropped from disk (using the Destroy opcode) in order to keep ** the internal representation of the ** schema consistent with what is on disk. */ case OP_DropTrigger: { sqlite3UnlinkAndDeleteTrigger(db, pOp->p1, pOp->p4.z); break; } |
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