During byte-code generation, strive to avoid jumps that merely jump to the

following instruction.

FossilOrigin-Name: bcf876e67e75f6709f2b25683a3952bbbb87c672bb9d7af456feebc0ab9f6c31

diff --git a/manifest b/manifest
index 6e923b7e4b0141ac8c7f5a49c876838827e675a0..b4353c625a990800e373e1c0607b06aea87c0394 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Simplify\sthe\scode\sby\sremoving\sthe\sunsupported\sand\sundocumented\s\nSQLITE_HAS_CODEC\scompile-time\soption
-D 2020-02-07T01:12:53.927
+C During\sbyte-code\sgeneration,\sstrive\sto\savoid\sjumps\sthat\smerely\sjump\sto\sthe\nfollowing\sinstruction.
+D 2020-02-07T19:44:13.184
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -482,10 +482,10 @@ F src/ctime.c 6a77ec9e0eb87aea929e002c816298907e337094a7b556898ae2d1e6be209f90
 F src/date.c 6c408fdd2e9ddf6e8431aba76315a2d061bea2cec8fbb75e25d7c1ba08274712
 F src/dbpage.c 8a01e865bf8bc6d7b1844b4314443a6436c07c3efe1d488ed89e81719047833a
 F src/dbstat.c 0f55297469d4244ab7df395849e1af98eb5e95816af7c661e7d2d8402dea23da
-F src/delete.c a5c59b9c0251cf7682bc52af0d64f09b1aefc6781a63592c8f1136f7b73c66e4
+F src/delete.c 11000121c4281c0bce4e41db29addfaea0038eaa127ece02557c9207bc3e541d
 F src/expr.c 6617ca8d4cc808b82348ae0c2844000b665de86aacc60fa0524f1b29b1918921
 F src/fault.c 460f3e55994363812d9d60844b2a6de88826e007
-F src/fkey.c 92a248ec0fa4ed8ab60c98d9b188ce173aaf218f32e7737ba77deb2a684f9847
+F src/fkey.c 4b575423b0a5d4898b1a7868ce985cf1a8ad91c741c9abbb108ff02536d20f41
 F src/func.c 108577cebe8a50c86d849a93b99493a54e348dd0b846f00d13b52ca973d5baf4
 F src/global.c 79a988b56b06ce2d08ebefe1d35da9aa25b3851faa47ea5233361c4827185a64
 F src/hash.c 8d7dda241d0ebdafb6ffdeda3149a412d7df75102cecfc1021c98d6219823b19
@@ -531,7 +531,7 @@ F src/printf.c 9be6945837c839ba57837b4bc3af349eba630920fa5532aa518816defe42a7d4
 F src/random.c 80f5d666f23feb3e6665a6ce04c7197212a88384
 F src/resolve.c f0781c9e180028b279bc4ff079ad54f4727223d470c8d2343643fcaf79b67740
 F src/rowset.c d977b011993aaea002cab3e0bb2ce50cf346000dff94e944d547b989f4b1fe93
-F src/select.c 3f7aecf64b08b018b89e4fe16ea621cc9a0e3f3801e9e5638cfe1a6035fa1581
+F src/select.c 28defa337bd913e4d1c6430016e0669bae42778ebe94dbdd855d12de073aa8da
 F src/shell.c.in c2e20c43a44fb5588a6c27ce60589538fbf4794fd7686f5b2598eca22eaae1fa
 F src/sqlite.h.in 572ea78b08ee90529d7588cea966c350afbf9624fdf133378edb346a233c6625
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
@@ -598,16 +598,16 @@ F src/threads.c 4ae07fa022a3dc7c5beb373cf744a85d3c5c6c3c
 F src/tokenize.c 7b17f6e2f20f6cbcb0b215025a86b7457c38451fc7622f705e553d7a488c572d
 F src/treeview.c 438c1000587b33faba35e87596bebcf7f40638d98f33781cdd9e04711b18b09c
 F src/trigger.c a40d50e88bd3355f1d2a73f0a3b2d6b42eae26ca4219001b82ef0d064439badc
-F src/update.c 9ad19af96aff95dc02a923a99f97c1bc0b909009a29a2914b796f786b9ac0c60
+F src/update.c 3eb778c42155d944377a4ee5e440b04520f07094804ed6ce63d2528f619614d9
 F src/upsert.c 2920de71b20f04fe25eb00b655d086f0ba60ea133c59d7fa3325c49838818e78
 F src/utf.c 736ff76753236ffbc8b5b939f5e0607f28aeaa7c780b3a56b419228f0a81c87b
 F src/util.c a285c1e026907b69fa2592bd05047a565a1d8a1aef2b73c924b6a8ffe772871a
 F src/vacuum.c 813b510ba887fee6492bcb11f2bf77d7eb58b232b83649136372e0a2fc17f4b9
 F src/vdbe.c 15cae95de3c1301747f7ee17a70046772741e7e630b6d5554c685b613798b8e8
-F src/vdbe.h defd693289c7bb8d325f109be9490c77138061211a116827da7244b6015a4934
+F src/vdbe.h 51282fbe819ee0e8eeeaab176240860d334c20a12b14f3b363e7f1a4e05d60b9
 F src/vdbeInt.h a17146053a1aa438474012998fe07e314f3df274a61491ad838ad85d848ac051
 F src/vdbeapi.c 1252d80c548711e47a6d84dae88ed4e95d3fbb4e7bd0eaa1347299af7efddf02
-F src/vdbeaux.c eaf1df6465f410e69330864bfc152458208f9bb2edd99930432ae342662d2ecd
+F src/vdbeaux.c c44f530a04e7a2461ac0c9e0e0d3dc91a4928ba4e027547ee0f5f7d8f3f65c3e
 F src/vdbeblob.c 253ed82894924c362a7fa3079551d3554cd1cdace39aa833da77d3bc67e7c1b1
 F src/vdbemem.c ff2a1fd86ea943efb7174bd74bc661815c449be6165e136e8849e1dc59e24353
 F src/vdbesort.c 2be76d26998ce2b3324cdcc9f6443728e54b6c7677c553ad909c7d7cfab587df
@@ -1858,7 +1858,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P a8a7c05b16f6c73ac55c359fbf62cae4a76eb0d105a3c53e9f47cede9fd85916
-R 014522d0d8b6f7e2f23a6a5506d80ae9
+P 5a877221ce90e7523059353a68650c5fdd28ed032807afc2f10afbfbf864bdfe
+R 0497976083176014d12d8c84100cdcac
 U drh
-Z bb09705c5da204b17eae60b0010baaaf
+Z 2fd9d06239e0afdc15eacc0b2447af10

diff --git a/manifest.uuid b/manifest.uuid
index 6aa6ce42b4a61352cfb64d77f83a882c51c0dd59..fcf697e987f98b989dd05e75478629ed574676a0 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-5a877221ce90e7523059353a68650c5fdd28ed032807afc2f10afbfbf864bdfe
\ No newline at end of file
+bcf876e67e75f6709f2b25683a3952bbbb87c672bb9d7af456feebc0ab9f6c31
\ No newline at end of file

diff --git a/src/delete.c b/src/delete.c
index 0a83f1b640605823fef25246e9ce39d078ace590..60efc9d56939b53c2f8c1c94778bad2ecead3aab 100644 (file)
--- a/src/delete.c
+++ b/src/delete.c
@@ -533,7 +533,9 @@ void sqlite3DeleteFrom(
                                  iTabCur, aToOpen, &iDataCur, &iIdxCur);
       assert( pPk || IsVirtual(pTab) || iDataCur==iTabCur );
       assert( pPk || IsVirtual(pTab) || iIdxCur==iDataCur+1 );
-      if( eOnePass==ONEPASS_MULTI ) sqlite3VdbeJumpHere(v, iAddrOnce);
+      if( eOnePass==ONEPASS_MULTI ){
+        sqlite3VdbeJumpHereOrPopInst(v, iAddrOnce);
+      }
     }
   
     /* Set up a loop over the rowids/primary-keys that were found in the

diff --git a/src/fkey.c b/src/fkey.c
index 9698d343ce2135b45960c0cb75b9a2e021ac85bf..7bc20fed0e94b3ddeb201bd6690b4208dcece6fb 100644 (file)
--- a/src/fkey.c
+++ b/src/fkey.c
@@ -658,7 +658,7 @@ static void fkScanChildren(
   /* Clean up the WHERE clause constructed above. */
   sqlite3ExprDelete(db, pWhere);
   if( iFkIfZero ){
-    sqlite3VdbeJumpHere(v, iFkIfZero);
+    sqlite3VdbeJumpHereOrPopInst(v, iFkIfZero);
   }
 }
 

diff --git a/src/select.c b/src/select.c
index 595b6eb6b227aa12f5cb1bd3f663fd8e09b4cca1..6f8d45c4eb794ba28121d844e280cc08f5137f33 100644 (file)
--- a/src/select.c
+++ b/src/select.c
@@ -5493,7 +5493,7 @@ static void updateAccumulator(Parse *pParse, int regAcc, AggInfo *pAggInfo){
 
   pAggInfo->directMode = 0;
   if( addrHitTest ){
-    sqlite3VdbeJumpHere(v, addrHitTest);
+    sqlite3VdbeJumpHereOrPopInst(v, addrHitTest);
   }
 }
 

diff --git a/src/update.c b/src/update.c
index 61b1740b42add060063bb85883a3a6c86cafe43f..d54a6cb9f073f198d48b961d7cd9e95041f56364 100644 (file)
--- a/src/update.c
+++ b/src/update.c
@@ -616,7 +616,9 @@ void sqlite3Update(
       }
       sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenWrite, 0, iBaseCur,
                                  aToOpen, 0, 0);
-      if( addrOnce ) sqlite3VdbeJumpHere(v, addrOnce);
+      if( addrOnce ){
+        sqlite3VdbeJumpHereOrPopInst(v, addrOnce);
+      }
     }
   
     /* Top of the update loop */

diff --git a/src/vdbe.h b/src/vdbe.h
index bfde25873fd5374a3887c125b9db79a6fd00790d..482331effa2f1f92f7c67a3f026c17965029be5d 100644 (file)
--- a/src/vdbe.h
+++ b/src/vdbe.h
@@ -230,6 +230,7 @@ void sqlite3VdbeChangeP2(Vdbe*, int addr, int P2);
 void sqlite3VdbeChangeP3(Vdbe*, int addr, int P3);
 void sqlite3VdbeChangeP5(Vdbe*, u16 P5);
 void sqlite3VdbeJumpHere(Vdbe*, int addr);
+void sqlite3VdbeJumpHereOrPopInst(Vdbe*, int addr);
 int sqlite3VdbeChangeToNoop(Vdbe*, int addr);
 int sqlite3VdbeDeletePriorOpcode(Vdbe*, u8 op);
 #ifdef SQLITE_DEBUG

diff --git a/src/vdbeaux.c b/src/vdbeaux.c
index 52959a43eeef23c6026b5f7c857c22ab9b24e3f1..2a47415734f77f0e057b74281ddaccf4e9d44fe6 100644 (file)
--- a/src/vdbeaux.c
+++ b/src/vdbeaux.c
@@ -1065,6 +1065,34 @@ void sqlite3VdbeJumpHere(Vdbe *p, int addr){
   sqlite3VdbeChangeP2(p, addr, p->nOp);
 }
 
+/*
+** Change the P2 operand of the jump instruction at addr so that
+** the jump lands on the next opcode.  Or if the jump instruction was
+** the previous opcode (and is thus a no-op) then simply back up
+** the next instruction counter by one slot so that the jump is
+** overwritten by the next inserted opcode.
+**
+** This routine is an optimization of sqlite3VdbeJumpHere() that
+** strives to omit useless byte-code like this:
+**
+**        7   Once 0 8 0
+**        8   ...
+*/
+void sqlite3VdbeJumpHereOrPopInst(Vdbe *p, int addr){
+  if( addr==p->nOp-1 ){
+    assert( p->aOp[addr].opcode==OP_Once
+         || p->aOp[addr].opcode==OP_If
+         || p->aOp[addr].opcode==OP_FkIfZero );
+    assert( p->aOp[addr].p4type==0 );
+#ifdef SQLITE_VDBE_COVERAGE
+    sqlite3VdbeGetOp(v,-1)->iSrcLine = 0;  /* Erase VdbeCoverage() macros */
+#endif
+    p->nOp--;
+  }else{
+    sqlite3VdbeChangeP2(p, addr, p->nOp);
+  }
+}
+
 
 /*
 ** If the input FuncDef structure is ephemeral, then free it.  If