[gcc r12-7541] analyzer: more test coverage of leak detection [PR99771]

[gcc r12-7541] analyzer: more test coverage of leak detection [PR99771]

[David Malcolm]

https://gcc.gnu.org/g:b7175f36812b32d3de242f15c065b9cb68e957a9

commit r12-7541-gb7175f36812b32d3de242f15c065b9cb68e957a9
Author: David Malcolm <dmalcolm@redhat.com>
Date:   Tue Mar 8 14:16:48 2022 -0500

    analyzer: more test coverage of leak detection [PR99771]
    
    gcc/testsuite/ChangeLog:
            PR analyzer/99771
            * gcc.dg/analyzer/leak-4.c: New test.
    
    Signed-off-by: David Malcolm <dmalcolm@redhat.com>

Diff:
---
 gcc/testsuite/gcc.dg/analyzer/leak-4.c | 103 +++++++++++++++++++++++++++++++++
 1 file changed, 103 insertions(+)

diff --git a/gcc/testsuite/gcc.dg/analyzer/leak-4.c b/gcc/testsuite/gcc.dg/analyzer/leak-4.c
new file mode 100644
index 00000000000..75090e6be83
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/analyzer/leak-4.c
@@ -0,0 +1,103 @@
+/* Various tests of memory leak detection.  */
+
+#include <stdlib.h>
+
+/* Example of an leak due to incomplete cleanup when freeing a struct.  */
+
+struct s1
+{
+  void *ptr;
+};
+
+void test_1 (void)
+{
+  struct s1 *a = malloc (sizeof (struct s1));
+  if (!a)
+    return;
+  a->ptr = malloc (1024); /* { dg-message "allocated here" } */
+  free (a); /* { dg-warning "leak of '<unknown>'" } */
+  /* TODO: we should print "a->ptr' here, rather than '<unknown>'
+     (PR analyzer/99771).  */
+}
+
+
+/* Examples involving arrays.  */
+
+struct s2
+{
+  void *m_arr[10];
+};
+
+void test_2a (void)
+{
+  struct s2 arr[5];
+  arr[3].m_arr[4] = malloc (1024); /* { dg-message "allocated here" } */
+} /* { dg-warning "leak of 'arr\\\[3\\\].m_arr\\\[4\\\]'" } */
+
+void test_2b (int i)
+{
+  struct s2 arr[5];
+  arr[3].m_arr[i] = malloc (1024); /* { dg-message "allocated here" } */
+} /* { dg-warning "leak of 'arr\\\[3\\\].m_arr\\\[i\\\]'" } */
+
+void test_2c (int i)
+{
+  struct s2 arr[5];
+  arr[i].m_arr[4] = malloc (1024); /* { dg-message "allocated here" } */
+} /* { dg-warning "leak of 'arr\\\[i\\\].m_arr\\\[4\\\]'" } */
+
+void test_2d (int i, int j)
+{
+  struct s2 arr[5];
+  arr[i].m_arr[j] = malloc (1024); /* { dg-message "allocated here" } */
+} /* { dg-warning "leak of 'arr\\\[i\\\].m_arr\\\[j\\\]'" } */
+
+
+/* Example involving fields.  */
+
+struct s3
+{
+  struct s3 *m_left;
+  struct s3 *m_right;  
+};
+
+void test_3 (void)
+{
+  struct s3 *a = malloc (sizeof (struct s3));
+  a->m_right = malloc (sizeof (struct s3)); /* { dg-warning "dereference of possibly-NULL 'a'" } */
+  a->m_right->m_left = malloc (sizeof (struct s3)); /* { dg-warning "dereference of possibly-NULL '\\*a.m_right'" } */
+} /* { dg-warning "leak of 'a'" "leak of a" } */
+/* { dg-warning "leak of '<unknown>'" "leak of unknown" { target *-*-* } .-1 } */
+/* TODO: rather than '<unknown>', we should print 'a->m_right'
+   and 'a->m_right->m_left' (PR analyzer/99771).  */
+
+
+/* Example involving faking inheritance via casts.  */
+
+struct s4_base
+{
+  int m_placeholder;
+};
+
+struct s4_sub
+{
+  void *m_buffer;
+};
+
+static struct s4_sub *
+make_s4_sub (void)
+{
+  struct s4_sub *sub = malloc (sizeof (struct s4_sub)); /* { dg-message "allocated here" } */
+  if (!sub)
+    return NULL;
+  sub->m_buffer = malloc (1024); /* { dg-message "allocated here" } */
+  return sub;
+}
+
+void test_4 (void)
+{
+  struct s4_base *base = (struct s4_base *)make_s4_sub ();
+} /* { dg-warning "leak of 'base'" "leak of base" } */
+/* { dg-warning "leak of '<unknown>'" "leak of sub buffer" { target *-*-* } .-1 } */
+/* TODO: rather than 'unknown', we should print something
+   like '((struct s4_sub *)base)->m_buffer' (PR analyzer/99771).  */