Fix ubsan error in opts-global.cc

Fixes:
opts-global.cc:75:15: runtime error: store to address 0x00000bc9be70 with insufficient space for an object of type 'char'
which happens when mask == 0, len == 0 and we allocate zero elements.
Eventually, result[0] is called which triggers the UBSAN.

gcc/ChangeLog:

	* opts-global.cc (write_langs): Allocate at least one byte.

diff --git a/gcc/opts-global.cc b/gcc/opts-global.cc
index a18c769..4f5f8cd 100644 (file)
--- a/gcc/opts-global.cc
+++ b/gcc/opts-global.cc
@@ -61,7 +61,7 @@ write_langs (unsigned int mask)
     if (mask & (1U << n))
       len += strlen (lang_name) + 1;
 
-  result = XNEWVEC (char, len);
+  result = XNEWVEC (char, MAX (1, len));
   len = 0;
   for (n = 0; (lang_name = lang_names[n]) != 0; n++)
     if (mask & (1U << n))