[PATCH v1] Fix wrong auxtype for storage class warning in AIX.

[Aditya Kamath]

Hi everyone,

Kindly let me know if any feedback for this patch.

Thanks and regards,
Aditya.

From: Aditya Vidyadhar Kamath <akamath996@gmail.com>
Date: Tuesday, 4 August 2026 at 12:15 PM
To: amodra@gmail.com <amodra@gmail.com>
Cc: binutils@sourceware.org <binutils@sourceware.org>; Aditya Kamath <Aditya.Kamath1@ibm.com>; SANGAMESH MALLAYYA <sangamesh.swamy@in.ibm.com>
Subject: [EXTERNAL] [PATCH v1] Fix wrong auxtype for storage class warning in AIX.

From: Aditya Kamath <Aditya.Kamath1@ibm.com>

In AIX when we debug a 64 bit binary we get,
warning: BFD: /usr/lib/libc.a(/usr/lib/libc.a(_shr_64.o)): wrong auxtype 0xff for storage class 0x6b
as shown below.

(gdb) b main
Breakpoint 1 at 0x1000008bc: file /tmp/inline_test/test_inline2.c, line 12.
(gdb) r
Starting program: /tmp/inline_test/test2_openxl
warning: BFD: /usr/lib/libc.a(/usr/lib/libc.a(_shr_64.o)): wrong auxtype 0xff for storage class 0x6b
warning: BFD: /usr/lib/libc.a(/usr/lib/libc.a(_shr_64.o)): wrong auxtype 0xff for storage class 0x2

Breakpoint 1, main () at /tmp/inline_test/test_inline2.c:12
12      volatile int x = 10, y = 20;
(gdb) q

The openXL compiled binary or library in AIX emits _AUX_EXCEPT (auxtype 0xff)
auxillary entry for C_EXT and C_HIDEXT symbols which are functions that have
exception tables. BFD's _bfd_xcoff64_swap_aux_in() only accepted _AUX_FCN for
non-last aux entries and jumped to error: for anything else triggering the spurious
warning. The fix detects _AUX_EXCEPT first and silently skips it with break,
since BFD does not need to parse its payload.
---
 bfd/coff64-rs6000.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/bfd/coff64-rs6000.c b/bfd/coff64-rs6000.c
index 8d558bdc0d2..d23c5d92541 100644
--- a/bfd/coff64-rs6000.c
+++ b/bfd/coff64-rs6000.c
@@ -425,9 +425,14 @@ _bfd_xcoff64_swap_aux_in (bfd *abfd, void *ext1, int type ATTRIBUTE_UNUSED,
         }
       else
         {
-         /* It can also be a _AUX_EXCEPT entry. But it's not supported
-            for now. */
           auxtype = H_GET_8 (abfd, ext->x_fcn.x_auxtype);
+         if (auxtype == _AUX_EXCEPT)
+           {
+             /* Exception-info auxiliary entry: skip it silently.  XLC
+                emits these for functions that have exception tables; BFD
+                does not need to interpret the payload.  */
+             break;
+           }
           if (auxtype != _AUX_FCN)
             goto error;

--
2.51.2

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