Avoid using large pass-by-value struct arguments in pgbench.

In the wake of commit 4a39f87ac, which noticeably increased the
size of struct StatsData and thereby ParsedScript, Coverity started
to complain that ParsedScript was unreasonably large to be passing
by value.  The two places that do this are only used during setup,
so they're not really dragging down benchmark measurements --- but
gratuitous inefficiency is not a good look in a benchmarking program.
Convert to use pointers instead.

src/bin/pgbench/pgbench.c

@@ -832,7 +832,7 @@ static void doLog(TState *thread, CState *st,
 				  StatsData *agg, bool skipped, double latency, double lag);
 static void processXactStats(TState *thread, CState *st, pg_time_usec_t *now,
 							 bool skipped, StatsData *agg);
-static void addScript(ParsedScript script);
+static void addScript(const ParsedScript *script);
 static THREAD_FUNC_RETURN_TYPE THREAD_FUNC_CC threadRun(void *arg);
 static void finishCon(CState *st);
 static void setalarm(int seconds);
@@ -5743,15 +5743,15 @@ ConditionError(const char *desc, int cmdn, const char *msg)
  * Partial evaluation of conditionals before recording and running the script.
  */
 static void
-CheckConditional(ParsedScript ps)
+CheckConditional(const ParsedScript *ps)
 {
 	/* statically check conditional structure */
 	ConditionalStack cs = conditional_stack_create();
 	int			i;
 
-	for (i = 0; ps.commands[i] != NULL; i++)
+	for (i = 0; ps->commands[i] != NULL; i++)
 	{
-		Command    *cmd = ps.commands[i];
+		Command    *cmd = ps->commands[i];
 
 		if (cmd->type == META_COMMAND)
 		{
@@ -5762,20 +5762,20 @@ CheckConditional(ParsedScript ps)
 					break;
 				case META_ELIF:
 					if (conditional_stack_empty(cs))
-						ConditionError(ps.desc, i + 1, "\\elif without matching \\if");
+						ConditionError(ps->desc, i + 1, "\\elif without matching \\if");
 					if (conditional_stack_peek(cs) == IFSTATE_ELSE_FALSE)
-						ConditionError(ps.desc, i + 1, "\\elif after \\else");
+						ConditionError(ps->desc, i + 1, "\\elif after \\else");
 					break;
 				case META_ELSE:
 					if (conditional_stack_empty(cs))
-						ConditionError(ps.desc, i + 1, "\\else without matching \\if");
+						ConditionError(ps->desc, i + 1, "\\else without matching \\if");
 					if (conditional_stack_peek(cs) == IFSTATE_ELSE_FALSE)
-						ConditionError(ps.desc, i + 1, "\\else after \\else");
+						ConditionError(ps->desc, i + 1, "\\else after \\else");
 					conditional_stack_poke(cs, IFSTATE_ELSE_FALSE);
 					break;
 				case META_ENDIF:
 					if (!conditional_stack_pop(cs))
-						ConditionError(ps.desc, i + 1, "\\endif without matching \\if");
+						ConditionError(ps->desc, i + 1, "\\endif without matching \\if");
 					break;
 				default:
 					/* ignore anything else... */
@@ -5784,7 +5784,7 @@ CheckConditional(ParsedScript ps)
 		}
 	}
 	if (!conditional_stack_empty(cs))
-		ConditionError(ps.desc, i + 1, "\\if without matching \\endif");
+		ConditionError(ps->desc, i + 1, "\\if without matching \\endif");
 	conditional_stack_destroy(cs);
 }
 
@@ -5916,7 +5916,7 @@ ParseScript(const char *script, const char *desc, int weight)
 
 	ps.commands[index] = NULL;
 
-	addScript(ps);
+	addScript(&ps);
 
 	termPQExpBuffer(&line_buf);
 	psql_scan_finish(sstate);
@@ -6093,11 +6093,11 @@ parseScriptWeight(const char *option, char **script)
 
 /* append a script to the list of scripts to process */
 static void
-addScript(ParsedScript script)
+addScript(const ParsedScript *script)
 {
-	if (script.commands == NULL || script.commands[0] == NULL)
+	if (script->commands == NULL || script->commands[0] == NULL)
 	{
-		pg_log_fatal("empty command list for script \"%s\"", script.desc);
+		pg_log_fatal("empty command list for script \"%s\"", script->desc);
 		exit(1);
 	}
 
@@ -6109,7 +6109,7 @@ addScript(ParsedScript script)
 
 	CheckConditional(script);
 
-	sql_script[num_scripts] = script;
+	sql_script[num_scripts] = *script;
 	num_scripts++;
 }