[binutils-gdb] ubsan: csky: left shift cannot be represented in type 'int'

[gdb-buildbot@sergiodj.net]

*** TEST RESULTS FOR COMMIT d93bba9e0d6c7bd3a570688612a3dd0a5eb0193a ***

commit d93bba9e0d6c7bd3a570688612a3dd0a5eb0193a
Author:     Alan Modra <amodra@gmail.com>
AuthorDate: Tue Dec 10 23:37:03 2019 +1030
Commit:     Alan Modra <amodra@gmail.com>
CommitDate: Wed Dec 11 11:38:45 2019 +1030

    ubsan: csky: left shift cannot be represented in type 'int'
    
    In the following buf is an unsigned char array, so elements are
    promoted to int before arithmetic operations.
    
      if (dis_info.info->endian == BFD_ENDIAN_BIG)
        while (n--)
          val |= buf[n] << (n*8);
      else
        for (i = 0; i < n; i++)
          val |= buf[i] << (i*8);
    
            * csky-dis.c (csky_chars_to_number): Rewrite.  Avoid signed
            overflow when collecting bytes of a number.

diff --git a/opcodes/ChangeLog b/opcodes/ChangeLog
index 6b76f158c9..5cd7361512 100644
--- a/opcodes/ChangeLog
+++ b/opcodes/ChangeLog
@@ -1,3 +1,8 @@
+2019-12-11  Alan Modra  <amodra@gmail.com>
+
+	* csky-dis.c (csky_chars_to_number): Rewrite.  Avoid signed
+	overflow when collecting bytes of a number.
+
 2019-12-11  Alan Modra  <amodra@gmail.com>
 
 	* cris-dis.c (print_with_operands): Avoid signed integer
diff --git a/opcodes/csky-dis.c b/opcodes/csky-dis.c
index ffdb596495..af830f3651 100644
--- a/opcodes/csky-dis.c
+++ b/opcodes/csky-dis.c
@@ -140,11 +140,11 @@ csky_chars_to_number (unsigned char * buf, int n)
   unsigned int val = 0;
 
   if (dis_info.info->endian == BFD_ENDIAN_BIG)
-    while (n--)
-      val |= buf[n] << (n*8);
-  else
     for (i = 0; i < n; i++)
-      val |= buf[i] << (i*8);
+      val = val << 8 | (buf[i] & 0xff);
+  else
+    for (i = n - 1; i >= 0; i--)
+      val = val << 8 | (buf[i] & 0xff);
   return val;
 }