From b11465f1150a11d6a9b186417c468c8191ae41a1 Mon Sep 17 00:00:00 2001
From: Martin Sebor <msebor@redhat.com>
Date: Tue, 1 Mar 2022 16:56:06 -0700
Subject: [PATCH] Add a test for true positives related to PR104715.
Related to:
PR tree-optimization/104715 - false dangling pointer with strstr
gcc/testsuite/ChangeLog:
PR tree-optimization/104715
* gcc.dg/Wdangling-pointer-3.c: New test.
---
gcc/testsuite/gcc.dg/Wdangling-pointer-3.c | 92 ++++++++++++++++++++++
1 file changed, 92 insertions(+)
create mode 100644 gcc/testsuite/gcc.dg/Wdangling-pointer-3.c
diff --git a/gcc/testsuite/gcc.dg/Wdangling-pointer-3.c b/gcc/testsuite/gcc.dg/Wdangling-pointer-3.c
new file mode 100644
index 000000000000..01859303fcfa
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Wdangling-pointer-3.c
@@ -0,0 +1,92 @@
+/* PR tree-optimization/104715 - false dangling pointer with strstr
+ Vertify that using pointers that have become dangling after they were
+ passed to and returned from strstr is diagnosed.
+ { dg-do compile }
+ { dg-options "-Wall" } */
+
+extern char* strstr (const char*, const char*);
+
+void sink (const void*);
+
+void nowarn_strstr_static (const char *s)
+{
+ char *t1;
+
+ {
+ static const char a[] = "abc";
+ t1 = strstr (a, s);
+ sink (t1);
+ }
+
+ sink (t1);
+}
+
+
+void nowarn_strstr_lit (const char *s)
+{
+ char *t2;
+
+ {
+ t2 = strstr ("def", s);
+ sink (t2);
+ }
+
+ sink (t2);
+}
+
+
+void warn_strstr_comp_lit (const char *s)
+{
+ char *t3;
+
+ {
+ const char *a =
+ (char[]){ '1', '\0' }; // { dg-message "unnamed temporary defined here" }
+ t3 = strstr (a, s);
+ sink (t3);
+ }
+
+ sink (t3); // { dg-warning "using dangling pointer 't3' to an unnamed temporary" }
+}
+
+
+void warn_strstr_arg (const char *s)
+{
+ char *t4;
+
+ {
+ char a[] = "1"; // { dg-message "'a' declared here" }
+ t4 = strstr (a, s);
+ sink (t4);
+ }
+
+ sink (t4); // { dg-warning "using dangling pointer 't4' to 'a'" }
+}
+
+
+void warn_strstr_arg_plus_cst (const char *s)
+{
+ char *t5;
+
+ {
+ char a[] = "12"; // { dg-message "'a' declared here" }
+ t5 = strstr (a + 1, s);
+ sink (t5);
+ }
+
+ sink (t5); // { dg-warning "using dangling pointer 't5' to 'a'" }
+}
+
+
+void warn_strstr_arg_plus_var (const char *s, int i)
+{
+ char *t6;
+
+ {
+ char a[] = "123"; // { dg-message "'a' declared here" }
+ t6 = strstr (a + i, s);
+ sink (t6++);
+ }
+
+ sink (t6); // { dg-warning "using dangling pointer 't6' to 'a'" }
+}
--
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