Initialize unused ExprEvalStep fields.

ExecPushExprSlots didn't initialize ExprEvalStep's resvalue/resnull
steps as it didn't use them. That caused wrong valgrind warnings for
an upcoming patch, so zero-intialize.

Also zero-initialize all scratch ExprEvalStep's allocated on the
stack, to avoid issues with similar future omissions of non-critial
data.

diff --git a/src/backend/executor/execExpr.c b/src/backend/executor/execExpr.c
index 883a29f0a7bbf87fd8aea6548837fd2612c5344c..c6eb3ebacf8e110cc2095f2a701099a3d5db59b2 100644 (file)
--- a/src/backend/executor/execExpr.c
+++ b/src/backend/executor/execExpr.c
@@ -118,7 +118,7 @@ ExprState *
 ExecInitExpr(Expr *node, PlanState *parent)
 {
    ExprState  *state;
-   ExprEvalStep scratch;
+   ExprEvalStep scratch = {0};
 
    /* Special case: NULL expression produces a NULL ExprState pointer */
    if (node == NULL)
@@ -155,7 +155,7 @@ ExprState *
 ExecInitExprWithParams(Expr *node, ParamListInfo ext_params)
 {
    ExprState  *state;
-   ExprEvalStep scratch;
+   ExprEvalStep scratch = {0};
 
    /* Special case: NULL expression produces a NULL ExprState pointer */
    if (node == NULL)
@@ -204,7 +204,7 @@ ExprState *
 ExecInitQual(List *qual, PlanState *parent)
 {
    ExprState  *state;
-   ExprEvalStep scratch;
+   ExprEvalStep scratch = {0};
    List       *adjust_jumps = NIL;
    ListCell   *lc;
 
@@ -353,7 +353,7 @@ ExecBuildProjectionInfo(List *targetList,
 {
    ProjectionInfo *projInfo = makeNode(ProjectionInfo);
    ExprState  *state;
-   ExprEvalStep scratch;
+   ExprEvalStep scratch = {0};
    ListCell   *lc;
 
    projInfo->pi_exprContext = econtext;
@@ -638,7 +638,7 @@ static void
 ExecInitExprRec(Expr *node, ExprState *state,
                Datum *resv, bool *resnull)
 {
-   ExprEvalStep scratch;
+   ExprEvalStep scratch = {0};
 
    /* Guard against stack overflow due to overly complex expressions */
    check_stack_depth();
@@ -2273,7 +2273,10 @@ ExecInitExprSlots(ExprState *state, Node *node)
 static void
 ExecPushExprSlots(ExprState *state, LastAttnumInfo *info)
 {
-   ExprEvalStep scratch;
+   ExprEvalStep scratch = {0};
+
+   scratch.resvalue = NULL;
+   scratch.resnull = NULL;
 
    /* Emit steps as needed */
    if (info->last_inner > 0)
@@ -2659,7 +2662,7 @@ static void
 ExecInitCoerceToDomain(ExprEvalStep *scratch, CoerceToDomain *ctest,
                       ExprState *state, Datum *resv, bool *resnull)
 {
-   ExprEvalStep scratch2;
+   ExprEvalStep scratch2 = {0};
    DomainConstraintRef *constraint_ref;
    Datum      *domainval = NULL;
    bool       *domainnull = NULL;
@@ -2811,7 +2814,7 @@ ExecBuildAggTrans(AggState *aggstate, AggStatePerPhase phase,
 {
    ExprState  *state = makeNode(ExprState);
    PlanState  *parent = &aggstate->ss.ps;
-   ExprEvalStep scratch;
+   ExprEvalStep scratch = {0};
    int         transno = 0;
    int         setoff = 0;
    bool        isCombine = DO_AGGSPLIT_COMBINE(aggstate->aggsplit);