From 6884e5cbd3ff4602cbfe80744decc7205867435d Mon Sep 17 00:00:00 2001
From: "D. Richard Hipp" <drh@hwaci.com>
Date: Tue, 10 Jul 2018 17:10:44 +0000
Subject: [PATCH] Further improvements to bytecode branch testing.  Fix cases
 where the macros said a branch could not be taken when in fact it could be. 
 Alter some window function branch coverage macros to indicate that comparison
 operands cannot be NULL.

---
 src/analyze.c |  5 +----
 src/update.c  |  2 +-
 src/vdbe.c    |  2 +-
 src/vdbe.h    |  3 +++
 src/window.c  | 12 ++++++------
 5 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/src/analyze.c b/src/analyze.c
index c3fa50b1c3..37b1eec0c7 100644
--- a/src/analyze.c
+++ b/src/analyze.c
@@ -1274,10 +1274,7 @@ static void analyzeOneTable(
       callStatGet(v, regStat4, STAT_GET_NLT, regLt);
       callStatGet(v, regStat4, STAT_GET_NDLT, regDLt);
       sqlite3VdbeAddOp4Int(v, seekOp, iTabCur, addrNext, regSampleRowid, 0);
-      /* We know that the regSampleRowid row exists because it was read by
-      ** the previous loop.  Thus the not-found jump of seekOp will never
-      ** be taken */
-      VdbeCoverageNeverTaken(v);
+      VdbeCoverage(v);
 #ifdef SQLITE_ENABLE_STAT3
       sqlite3ExprCodeLoadIndexColumn(pParse, pIdx, iTabCur, 0, regSample);
 #else
diff --git a/src/update.c b/src/update.c
index 9860943c0e..926e29e754 100644
--- a/src/update.c
+++ b/src/update.c
@@ -523,7 +523,7 @@ void sqlite3Update(
       if( !isView && aiCurOnePass[0]!=iDataCur && aiCurOnePass[1]!=iDataCur ){
         assert( pPk );
         sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, labelBreak, regKey,nKey);
-        VdbeCoverageNeverTaken(v);
+        VdbeCoverage(v);
       }
       if( eOnePass!=ONEPASS_SINGLE ){
         labelContinue = sqlite3VdbeMakeLabel(v);
diff --git a/src/vdbe.c b/src/vdbe.c
index 83f75ae309..f9c7eba91a 100644
--- a/src/vdbe.c
+++ b/src/vdbe.c
@@ -180,7 +180,7 @@ int sqlite3_found_count = 0;
     if( M==2 ) I |= 0x04;
     if( M==4 ){
       I |= 0x08;
-      if( (I&0x05)!=0 ) I |= 0x05;
+      if( (mNever&0x08)!=0 && (I&0x05)!=0) I |= 0x05; /*NO_TEST*/
     }
     sqlite3GlobalConfig.xVdbeBranch(sqlite3GlobalConfig.pVdbeBranchArg,
                                     iSrcLine&0xffffff, I, M);
diff --git a/src/vdbe.h b/src/vdbe.h
index 4725242c57..183242a7be 100644
--- a/src/vdbe.h
+++ b/src/vdbe.h
@@ -351,6 +351,8 @@ int sqlite3NotPureFunc(sqlite3_context*);
          sqlite3VdbeSetLineNumber(v,__LINE__|0x6000000);
 # define VdbeCoverageNeverNull(v) \
          sqlite3VdbeSetLineNumber(v,__LINE__|0x4000000);
+# define VdbeCoverageNeverNullIf(v,x) \
+         if(x)sqlite3VdbeSetLineNumber(v,__LINE__|0x4000000);
 # define VdbeCoverageEqNe(v) \
          sqlite3VdbeSetLineNumber(v,__LINE__|0x8000000);
 # define VDBE_OFFSET_LINENO(x) (__LINE__+x)
@@ -360,6 +362,7 @@ int sqlite3NotPureFunc(sqlite3_context*);
 # define VdbeCoverageAlwaysTaken(v)
 # define VdbeCoverageNeverTaken(v)
 # define VdbeCoverageNeverNull(v)
+# define VdbeCoverageNeverNullIf(v,x)
 # define VdbeCoverageEqNe(v)
 # define VDBE_OFFSET_LINENO(x) 0
 #endif
diff --git a/src/window.c b/src/window.c
index 5caaaa6ddb..6a50d7c0a2 100644
--- a/src/window.c
+++ b/src/window.c
@@ -1038,9 +1038,9 @@ static void windowCheckIntValue(Parse *pParse, int reg, int eCond){
   VdbeCoverageIf(v, eCond==1);
   VdbeCoverageIf(v, eCond==2);
   sqlite3VdbeAddOp3(v, aOp[eCond], regZero, sqlite3VdbeCurrentAddr(v)+2, reg);
-  VdbeCoverageIf(v, eCond==0);
-  VdbeCoverageIf(v, eCond==1);
-  VdbeCoverageIf(v, eCond==2);
+  VdbeCoverageNeverNullIf(v, eCond==0);
+  VdbeCoverageNeverNullIf(v, eCond==1);
+  VdbeCoverageNeverNullIf(v, eCond==2);
   sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_ERROR, OE_Abort);
   sqlite3VdbeAppendP4(v, (void*)azErr[eCond], P4_STATIC);
   sqlite3ReleaseTempReg(pParse, regZero);
@@ -1308,7 +1308,7 @@ static void windowReturnOneRow(
       }
       sqlite3VdbeAddOp3(v, OP_Add, tmpReg, pWin->regApp, tmpReg);
       sqlite3VdbeAddOp3(v, OP_Gt, pWin->regApp+1, lbl, tmpReg);
-      VdbeCoverage(v);
+      VdbeCoverageNeverNull(v);
       sqlite3VdbeAddOp3(v, OP_SeekRowid, csr, lbl, tmpReg);
       VdbeCoverage(v);
       sqlite3VdbeAddOp3(v, OP_Column, csr, pWin->iArgCol, pWin->regResult);
@@ -1621,7 +1621,7 @@ static void windowCodeRowExprStep(
     assert( pMWin->pStart!=0 );
     assert( pMWin->eEnd==TK_FOLLOWING );
     sqlite3VdbeAddOp3(v, OP_Ge, regStart, sqlite3VdbeCurrentAddr(v)+2, regEnd);
-    VdbeCoverage(v);
+    VdbeCoverageNeverNull(v);
     sqlite3VdbeAddOp2(v, OP_Copy, regSize, regStart);
     sqlite3VdbeAddOp3(v, OP_Subtract, regStart, regEnd, regEnd);
   }
@@ -1630,7 +1630,7 @@ static void windowCodeRowExprStep(
     assert( pMWin->pEnd!=0 );
     assert( pMWin->eStart==TK_PRECEDING );
     sqlite3VdbeAddOp3(v, OP_Le, regStart, sqlite3VdbeCurrentAddr(v)+3, regEnd);
-    VdbeCoverage(v);
+    VdbeCoverageNeverNull(v);
     sqlite3VdbeAddOp2(v, OP_Copy, regSize, regStart);
     sqlite3VdbeAddOp2(v, OP_Copy, regSize, regEnd);
   }
-- 
2.11.4.GIT