[src/trunk]: src/usr.bin/xlint/lint1 lint: fix bugs in dprint_node in debug m...

[rillig <rillig%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/948f63694c7b
branches:  trunk
changeset: 979658:948f63694c7b
user:      rillig <rillig%NetBSD.org@localhost>
date:      Mon Jan 04 21:30:06 2021 +0000

description:
lint: fix bugs in dprint_node in debug mode (since today)

The node was dereferenced before the null check.  GCC 5.5 didn't warn
about this obvious bug, not even with -Wall -Wextra -O2.  Such a case
didn't occur though in the few tests that this function was used in.

The indentation for the nested nodes only needs to be set for a few
lines of code, make this region as small as possible.

There are nodes that use both tn_left and tn_right, even though they are
not defined as binary operators.  An example is CALL, for which tn_left
is the address of the function name and tn_right, which are the
arguments, linked via PUSH nodes.  CALL is not a binary operator since
it doesn't do any calculations with its arguments.

diffstat:

 usr.bin/xlint/lint1/tree.c |  53 +++++++--------------------------------------
 1 files changed, 9 insertions(+), 44 deletions(-)

diffs (102 lines):

diff -r 6eba51ec183d -r 948f63694c7b usr.bin/xlint/lint1/tree.c
--- a/usr.bin/xlint/lint1/tree.c        Mon Jan 04 21:17:31 2021 +0000
+++ b/usr.bin/xlint/lint1/tree.c        Mon Jan 04 21:30:06 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: tree.c,v 1.125 2021/01/04 21:17:31 rillig Exp $        */
+/*     $NetBSD: tree.c,v 1.126 2021/01/04 21:30:06 rillig Exp $        */
 
 /*
  * Copyright (c) 1994, 1995 Jochen Pohl
@@ -37,7 +37,7 @@
 
 #include <sys/cdefs.h>
 #if defined(__RCSID) && !defined(lint)
-__RCSID("$NetBSD: tree.c,v 1.125 2021/01/04 21:17:31 rillig Exp $");
+__RCSID("$NetBSD: tree.c,v 1.126 2021/01/04 21:30:06 rillig Exp $");
 #endif
 
 #include <float.h>
@@ -91,64 +91,27 @@
 
 extern sig_atomic_t fpe;
 
-#if 0
-static char *
-dumpnode(char *buf, size_t len, tnode_t *tn) {
-       const char *n = getopname(tn->tn_op);
-       const char *s;
-
-       switch (tn->tn_op) {
-       case NAME:
-               s = tn->tn_sym->s_name;
-               break;
-       case CON:
-       case STRING:
-               s = "*";        /* todo */
-               break;
-       default:
-               s = NULL;
-               break;
-       }
-       char lb[1024];
-       char rb[1024];
-
-       if (s == NULL && tn->tn_left != NULL)
-               dumpnode(lb, sizeof(lb), tn->tn_left);
-       else
-               strcpy(lb, "(null)");
-
-       if (s == NULL && tn->tn_right != NULL)
-               dumpnode(rb, sizeof(rb), tn->tn_right);
-       else
-               strcpy(rb, "(null)");
-
-
-       snprintf(buf, len, "%s: (%s) = %s [%s, %s]", n,
-           type_name(tn->tn_type), s, lb, rb);
-       return buf;
-}
-#endif
-
 #ifdef DEBUG
 static void
 dprint_node(const tnode_t *tn)
 {
        static int indent = 0;
 
-       op_t op = tn->tn_op;
+       op_t op;
 
        if (tn == NULL) {
                printf("%*s" "null\n", indent, "");
                return;
        }
 
+       op = tn->tn_op;
        printf("%*s%s: %s%s%s",
            indent, "",
            op == CVT && !tn->tn_cast ? "convert" :
                op == NAME ? "name" : getopname(op),
            type_name(tn->tn_type), tn->tn_lvalue ? " lvalue" : "",
            tn->tn_parenthesized ? " ()" : "");
-       indent += 2;
+
        if (op == NAME)
                printf(" %s\n", tn->tn_sym->s_name);
        else if (op == CON)
@@ -157,11 +120,13 @@
                printf(" length=%zu\n", tn->tn_string->st_len);
        else {
                printf("\n");
+
+               indent += 2;
                dprint_node(tn->tn_left);
-               if (modtab[op].m_binary)
+               if (modtab[op].m_binary || tn->tn_right != NULL)
                        dprint_node(tn->tn_right);
+               indent -= 2;
        }
-       indent -= 2;
 }
 #else
 /*ARGSUSED*/