[binutils-gdb] Avoid crash with cross-linux core file

[Tom Tromey <tromey@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=c0e0d6bcfed32f7bdb76c92b319148e7b25eabd0

commit c0e0d6bcfed32f7bdb76c92b319148e7b25eabd0
Author: Tom Tromey <tromey@adacore.com>
Date:   Mon Dec 13 14:43:18 2021 -0700

    Avoid crash with cross-linux core file
    
    An internal test case creates a core file using gcore, then restarts
    gdb with that core.  When run with a cross-linux gdb (in this case,
    x86-64 host with ppc64-linux target), the test fails:
    
        | (gdb) core core
        | [New LWP 18437]
        | warning: `/lib64/libc.so.6': Shared library architecture unknown is not compatible with target architecture powerpc:common64.
        | warning: Could not load shared library symbols for /lib64/ld64.so.1.
        | Do you need "set solib-search-path" or "set sysroot"?
        | ../../src/gdb/gdbarch.c:3388: internal-error: int gdbarch_elf_make_msymbol_special_p(gdbarch*): Assertion `gdbarch != NULL' failed.
        | A problem internal to GDB has been detected,
        | further debugging may prove unreliable.
        | Quit this debugging session? (y or n) y
    
    What's happening here is that the core file lists some shared
    libraries.  These aren't available via the solib search path, and so
    gdb finds the local (x86-64) libraries.  This is not ideal, but on the
    other hand, it is what was asked for -- while the test does set
    solib-search-path, it does not set the sysroot.
    
    But, because gdb isn't configured to handle these libraries, it
    crashes.
    
    It seems to me that it's better to avoid the crash by having
    solib_bfd_open fail in the case where a library is incompatible.  That
    is what this patch does.  Now it looks like:
    
        | [New LWP 15488]
        | Error while mapping shared library sections:
        | `/lib64/libc.so.6': Shared library architecture unknown is not compatible with target architecture powerpc:common64.
    
    ... and does not crash gdb.
    
    I don't have a good setup for testing this using dejagnu, so I don't
    know whether an existing gdb test covers this scenario.

Diff:
---
 gdb/solib.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/gdb/solib.c b/gdb/solib.c
index b9b1d037187..8bcbfa22df1 100644
--- a/gdb/solib.c
+++ b/gdb/solib.c
@@ -511,10 +511,10 @@ solib_bfd_open (const char *pathname)
   /* Check bfd arch.  */
   b = gdbarch_bfd_arch_info (target_gdbarch ());
   if (!b->compatible (b, bfd_get_arch_info (abfd.get ())))
-    warning (_("`%s': Shared library architecture %s is not compatible "
-	       "with target architecture %s."), bfd_get_filename (abfd.get ()),
-	     bfd_get_arch_info (abfd.get ())->printable_name,
-	     b->printable_name);
+    error (_("`%s': Shared library architecture %s is not compatible "
+	     "with target architecture %s."), bfd_get_filename (abfd.get ()),
+	   bfd_get_arch_info (abfd.get ())->printable_name,
+	   b->printable_name);
 
   return abfd;
 }