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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug ipa/112783] core dump on libxo when function is inlined
Date: Fri, 01 Dec 2023 23:53:55 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D112783

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |INVALID

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
The problem is not in GCC but rather a bad assumption on the code part.

Basically we have:

memcpy(nbuf, name, nlen);
...


if (!name)
...


But the check after a memcpy can be removed as passing a null pointer to me=
mcpy
is undefined even if nlen is 0 here.


This patch to the sources fixes the issue for me:
```
diff --git a/libxo/libxo.c b/libxo/libxo.c
index 916a111..ea71723 100644
--- a/libxo/libxo.c
+++ b/libxo/libxo.c
@@ -4300,7 +4300,8 @@ xo_format_value (xo_handle_t *xop, const char *name,
ssize_t nlen,
        if ((xsp->xs_flags & (XSF_EMIT | XSF_EMIT_KEY))
            || !(xsp->xs_flags & XSF_EMIT_LEAF_LIST)) {
            char nbuf[nlen + 1];
-           memcpy(nbuf, name, nlen);
+            if (name)
+             memcpy(nbuf, name, nlen);
            nbuf[nlen] =3D '\0';

            ssize_t rc =3D xo_transition(xop, 0, nbuf, XSS_EMIT_LEAF_LIST);
@@ -4324,7 +4325,8 @@ xo_format_value (xo_handle_t *xop, const char *name,
ssize_t nlen,

        } else if (!(xsp->xs_flags & XSF_EMIT_KEY)) {
            char nbuf[nlen + 1];
-           memcpy(nbuf, name, nlen);
+            if (name)
+             memcpy(nbuf, name, nlen);
            nbuf[nlen] =3D '\0';

            ssize_t rc =3D xo_transition(xop, 0, nbuf, XSS_EMIT);
@@ -4342,7 +4344,8 @@ xo_format_value (xo_handle_t *xop, const char *name,
ssize_t nlen,
        if ((xsp->xs_flags & XSF_EMIT_LEAF_LIST)
            || !(xsp->xs_flags & XSF_EMIT)) {
            char nbuf[nlen + 1];
-           memcpy(nbuf, name, nlen);
+            if (name)
+             memcpy(nbuf, name, nlen);
            nbuf[nlen] =3D '\0';

            ssize_t rc =3D xo_transition(xop, 0, nbuf, XSS_EMIT);

```=