[binutils-gdb] PR26508 UBSAN: tc-xtensa.c:7764 null pointer bsearch

[Alan Modra]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=e637b7ba2f8399ba94721be3f1765b471b6a67c2

commit e637b7ba2f8399ba94721be3f1765b471b6a67c2
Author: Alan Modra <amodra@gmail.com>
Date:   Wed Aug 26 20:28:40 2020 +0930

    PR26508 UBSAN: tc-xtensa.c:7764 null pointer bsearch
    
            PR 26508
            * config/tc-xtensa.c (xg_get_trampoline_chain): Return early
            when n_entries is zero.

Diff:
---
 gas/ChangeLog          | 6 ++++++
 gas/config/tc-xtensa.c | 3 +++
 2 files changed, 9 insertions(+)

diff --git a/gas/ChangeLog b/gas/ChangeLog
index c56b992685c..c0d9b26a29c 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,9 @@
+2020-08-26  Alan Modra  <amodra@gmail.com>
+
+	PR 26508
+	* config/tc-xtensa.c (xg_get_trampoline_chain): Return early
+	when n_entries is zero.
+
 2020-08-26  Alan Modra  <amodra@gmail.com>
 
 	PR 26448
diff --git a/gas/config/tc-xtensa.c b/gas/config/tc-xtensa.c
index 82ec4393322..af4c66721a6 100644
--- a/gas/config/tc-xtensa.c
+++ b/gas/config/tc-xtensa.c
@@ -7753,6 +7753,9 @@ xg_get_trampoline_chain (struct trampoline_seg *ts,
   struct trampoline_chain_index *idx = &ts->chain_index;
   struct trampoline_chain c;
 
+  if (idx->n_entries == 0)
+    return NULL;
+
   if (idx->needs_sorting)
     {
       qsort (idx->entry, idx->n_entries, sizeof (*idx->entry),