[pypy-commit] stmgc use-gcc: Add a bug example

[arigo]

Author: Armin Rigo <arigo at tunes.org>
Branch: use-gcc
Changeset: r1888:4cf19da2ec99
Date: 2015-07-02 13:25 +0200
http://bitbucket.org/pypy/stmgc/changeset/4cf19da2ec99/

Log:	Add a bug example

diff --git a/gcc-seg-gs/bug1.c b/gcc-seg-gs/bug1.c
new file mode 100644
--- /dev/null
+++ b/gcc-seg-gs/bug1.c
@@ -0,0 +1,21 @@
+typedef struct {
+    int a[20];
+} foo_t;
+
+
+int sum1(__seg_gs foo_t *p)
+{
+    int i, total=0;
+    for (i=0; i<20; i++)
+        total += p->a[i];
+    return total;
+}
+
+int sum2(void)
+{
+    __seg_gs foo_t *p = (__seg_gs foo_t *)0x1234;
+    int i, total=0;
+    for (i=0; i<20; i++)
+        total += p->a[i];     // <= this memory read is missing %gs:
+    return total;
+}