[PATCH] gdb/testsuite: skip ada-valprint-error with clang

[Bratislav Filipovic <bfilipov@amd.com>]

The ada-valprint-error.exp test fails when compiled with clang due
to a linker relocation issue in the test infrastructure, not a GDB
bug.

The test compiles ada-valprint-error.c with nodebug flags, then
links it with a separate DWARF .o file generated by lib/dwarf.exp.
The C source defines:

    int buffer[] = {0, 0};
    void *fd__global = &buffer;

This requires the linker to apply an R_X86_64_64 relocation to
store buffer's address into fd__global.  With GCC, the linker
correctly applies this relocation.  With clang, the linker fails
to apply it, leaving fd__global as NULL.

Binary evidence:
- GCC binary: fd__global = 0x4020 (correct address of buffer)
- Clang binary: fd__global = 0x0 (NULL)

Both .o files contain the R_X86_64_64 relocation entry, but the
final linked binary differs:
- GCC emits fd__global in .data.rel.local section -> relocation works
- Clang emits fd__global in .data section -> relocation fails

This appears to be a toolchain/testsuite compatibility issue when
linking nodebug object files with separate DWARF objects.  Skip
the test for clang to avoid false failures.

Tested on x86_64-linux-gnu with both GCC and clang.

---
 gdb/testsuite/gdb.dwarf2/ada-valprint-error.exp | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/gdb/testsuite/gdb.dwarf2/ada-valprint-error.exp b/gdb/testsuite/gdb.dwarf2/ada-valprint-error.exp
index f3d61e91..c23d58a8 100644
--- a/gdb/testsuite/gdb.dwarf2/ada-valprint-error.exp
+++ b/gdb/testsuite/gdb.dwarf2/ada-valprint-error.exp
@@ -14,6 +14,14 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 load_lib dwarf.exp
 
+# Clang's linker fails to apply relocations when linking nodebug .o
+# with separate DWARF .o, resulting in fd__global being NULL instead
+# of pointing to buffer.
+if {[test_compiler_info "clang-*"]} {
+    unsupported "clang linker relocation issue with nodebug+DWARF linking"
+    return
+}
+
 # This test can only be run on targets which support DWARF-2 and use gas.
 require dwarf2_support
 
-- 
2.43.0