[src/trunk]: src/usr.bin/xlint/lint1 lint: fix crash after syntax error in GC...

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

details:   https://anonhg.NetBSD.org/src/rev/b921d507fcbb
branches:  trunk
changeset: 364653:b921d507fcbb
user:      rillig <rillig%NetBSD.org@localhost>
date:      Sun Apr 03 00:39:32 2022 +0000

description:
lint: fix crash after syntax error in GCC statement expression

Since cgram.y 1.226 from 2021-05-03.

diffstat:

 tests/usr.bin/xlint/lint1/d_gcc_compound_statements1.c   |  15 ++++++++++++++-
 tests/usr.bin/xlint/lint1/d_gcc_compound_statements1.exp |   1 +
 usr.bin/xlint/lint1/tree.c                               |  11 +++++++----
 3 files changed, 22 insertions(+), 5 deletions(-)

diffs (76 lines):

diff -r 4105a6a6e1c5 -r b921d507fcbb tests/usr.bin/xlint/lint1/d_gcc_compound_statements1.c
--- a/tests/usr.bin/xlint/lint1/d_gcc_compound_statements1.c    Sat Apr 02 22:38:45 2022 +0000
+++ b/tests/usr.bin/xlint/lint1/d_gcc_compound_statements1.c    Sun Apr 03 00:39:32 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: d_gcc_compound_statements1.c,v 1.7 2022/01/15 14:22:03 rillig Exp $    */
+/*     $NetBSD: d_gcc_compound_statements1.c,v 1.8 2022/04/03 00:39:32 rillig Exp $    */
 # 3 "d_gcc_compound_statements1.c"
 
 /* GCC compound statement with expression */
@@ -37,3 +37,16 @@
                0->e;
        });
 }
+
+void
+crash(void)
+{
+       /*
+        * Before tree.c 1.418 from 2022-04-03, lint dereferenced a null
+        * pointer in do_statement_expr.
+        */
+       ({
+               /* expect+1: error: syntax error ';' [249] */
+               ;
+       });
+}
diff -r 4105a6a6e1c5 -r b921d507fcbb tests/usr.bin/xlint/lint1/d_gcc_compound_statements1.exp
--- a/tests/usr.bin/xlint/lint1/d_gcc_compound_statements1.exp  Sat Apr 02 22:38:45 2022 +0000
+++ b/tests/usr.bin/xlint/lint1/d_gcc_compound_statements1.exp  Sun Apr 03 00:39:32 2022 +0000
@@ -1,3 +1,4 @@
 d_gcc_compound_statements1.c(24): error: syntax error 'return outside function' [249]
 d_gcc_compound_statements1.c(25): error: cannot initialize 'int' from 'void' [185]
 d_gcc_compound_statements1.c(37): error: type 'int' does not have member 'e' [101]
+d_gcc_compound_statements1.c(50): error: syntax error ';' [249]
diff -r 4105a6a6e1c5 -r b921d507fcbb usr.bin/xlint/lint1/tree.c
--- a/usr.bin/xlint/lint1/tree.c        Sat Apr 02 22:38:45 2022 +0000
+++ b/usr.bin/xlint/lint1/tree.c        Sun Apr 03 00:39:32 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: tree.c,v 1.417 2022/04/02 22:38:45 rillig Exp $        */
+/*     $NetBSD: tree.c,v 1.418 2022/04/03 00:39:32 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 1.417 2022/04/02 22:38:45 rillig Exp $");
+__RCSID("$NetBSD: tree.c,v 1.418 2022/04/03 00:39:32 rillig Exp $");
 #endif
 
 #include <float.h>
@@ -4546,18 +4546,21 @@
 {
        block_level--;
        mem_block_level--;
-       stmt_exprs->se_sym = mktempsym(block_dup_type(tn->tn_type));
+       stmt_exprs->se_sym = tn != NULL
+           ? mktempsym(block_dup_type(tn->tn_type))
+           : NULL;             /* after a syntax error */
        mem_block_level++;
        block_level++;
        /* ({ }) is a GCC extension */
        gnuism(320);
-
 }
 
 tnode_t *
 end_statement_expr(void)
 {
        stmt_expr *se = stmt_exprs;
+       if (se->se_sym == NULL)
+               return NULL;    /* after a syntax error */
        tnode_t *tn = build_name(se->se_sym, false);
        (void)expr_save_memory();       /* leak */
        expr_restore_memory(se->se_mem);