Module Name:    src
Committed By:   rillig
Date:           Wed Jun 30 11:29:29 UTC 2021

Modified Files:
        src/usr.bin/xlint/lint1: func.c

Log Message:
lint: invert condition in control flow analysis of switch statements

The condition previously contained many negations, which was hard to
understand.

No functional change.


To generate a diff of this commit:
cvs rdiff -u -r1.111 -r1.112 src/usr.bin/xlint/lint1/func.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.

Modified files:

Index: src/usr.bin/xlint/lint1/func.c
diff -u src/usr.bin/xlint/lint1/func.c:1.111 src/usr.bin/xlint/lint1/func.c:1.112
--- src/usr.bin/xlint/lint1/func.c:1.111	Sat Jun 19 19:59:02 2021
+++ src/usr.bin/xlint/lint1/func.c	Wed Jun 30 11:29:29 2021
@@ -1,4 +1,4 @@
-/*	$NetBSD: func.c,v 1.111 2021/06/19 19:59:02 rillig Exp $	*/
+/*	$NetBSD: func.c,v 1.112 2021/06/30 11:29:29 rillig Exp $	*/
 
 /*
  * Copyright (c) 1994, 1995 Jochen Pohl
@@ -37,7 +37,7 @@
 
 #include <sys/cdefs.h>
 #if defined(__RCSID) && !defined(lint)
-__RCSID("$NetBSD: func.c,v 1.111 2021/06/19 19:59:02 rillig Exp $");
+__RCSID("$NetBSD: func.c,v 1.112 2021/06/30 11:29:29 rillig Exp $");
 #endif
 
 #include <stdlib.h>
@@ -747,12 +747,11 @@ switch2(void)
 
 	lint_assert(cstmt->c_switch_type != NULL);
 
-	/*
-	 * If the switch expression was of type enumeration, count the case
-	 * labels and the number of enumerators. If both counts are not
-	 * equal print a warning.
-	 */
 	if (cstmt->c_switch_type->t_is_enum) {
+		/*
+		 * Warn if the number of case labels is different from the
+		 * number of enumerators.
+		 */
 		nenum = nclab = 0;
 		lint_assert(cstmt->c_switch_type->t_enum != NULL);
 		for (esym = cstmt->c_switch_type->t_enum->en_first_enumerator;
@@ -771,22 +770,25 @@ switch2(void)
 
 	if (cstmt->c_break) {
 		/*
-		 * end of switch always reached (c_break is only set if the
-		 * break statement can be reached).
+		 * The end of the switch statement is always reached since
+		 * c_break is only set if a break statement can actually
+		 * be reached.
 		 */
 		set_reached(true);
-	} else if (!cstmt->c_default &&
-		   (!hflag || !cstmt->c_switch_type->t_is_enum ||
-		    nenum != nclab)) {
+	} else if (cstmt->c_default ||
+		   (hflag && cstmt->c_switch_type->t_is_enum &&
+		    nenum == nclab)) {
 		/*
-		 * there are possible values which are not handled in
-		 * switch
+		 * The end of the switch statement is reached if the end
+		 * of the last statement inside it is reached.
 		 */
-		set_reached(true);
-	}	/*
-		 * otherwise the end of the switch expression is reached
-		 * if the end of the last statement inside it is reached.
+	} else {
+		/*
+		 * There are possible values that are not handled in the
+		 * switch statement.
 		 */
+		set_reached(true);
+	}
 
 	end_control_statement(CS_SWITCH);
 }

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