[binutils-gdb] Disable gdb.ada/dgopt.exp with gnat-llvm

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=12743d8290311a090ba115978d72351a2b321ce0

commit 12743d8290311a090ba115978d72351a2b321ce0
Author: Tom Tromey <[email protected]>
Date:   Fri Jun 26 07:00:47 2026 -0600

    Disable gdb.ada/dgopt.exp with gnat-llvm
    
    gdb.ada/dgopt.exp fails with gnat-llvm.
    
    Looking into it, it turns out that this test case relies on a bug in
    GNAT.  In particular, despite the use of -gnatDG, GNAT will still put
    a reference to "x.adb" into both the DWARF .debug_info and into the
    line table.  The test relies on this, because the original problem
    being fixed here is that, when the test was written, there was a bug
    causing these references to be dropped when writing .debug_names.
    
    gnat-llvm does not have this same bug -- it only emits references to
    x.adb.dg.
    
    This patch disables this test for gnat-llvm.  There's not really a
    good way to tell that gnatmake is llvm-based, so while I've added a
    new caching proc for this, it is just a proxy for an existing proc.
    
    Since this only affects gnat-llvm, and was discussed internally, I am
    going to check it in.

Diff:
---
 gdb/testsuite/gdb.ada/dgopt.exp | 8 ++++++++
 gdb/testsuite/lib/ada.exp       | 8 ++++++++
 2 files changed, 16 insertions(+)

diff --git a/gdb/testsuite/gdb.ada/dgopt.exp b/gdb/testsuite/gdb.ada/dgopt.exp
index 9e8e8a676a8..831aa053f36 100644
--- a/gdb/testsuite/gdb.ada/dgopt.exp
+++ b/gdb/testsuite/gdb.ada/dgopt.exp
@@ -19,6 +19,14 @@ load_lib "ada.exp"
 
 require allow_ada_tests
 
+# Despite appearances, this is not really an "Ada" test -- instead the
+# scenario here is that GNAT ends up putting one reference to x.adb
+# into the DWARF (whereas it mostly refers to x.adb.dg); and this
+# reference was being incorrectly omitted from .debug_names.
+# gnat-llvm does not have this bug, so the test does not make sense
+# there.
+require !using_gnat_llvm
+
 standard_ada_testfile x
 
 if {[gdb_compile_ada "${srcfile}" "${binfile}" executable \
diff --git a/gdb/testsuite/lib/ada.exp b/gdb/testsuite/lib/ada.exp
index 8c9821bb897..e20b35c8ebe 100644
--- a/gdb/testsuite/lib/ada.exp
+++ b/gdb/testsuite/lib/ada.exp
@@ -292,6 +292,14 @@ gdb_caching_proc ada_minimal_encodings {} {
 		additional_flags=-fgnat-encodings=minimal]
 }
 
+# Return 1 if GNAT is based on LLVM.
+gdb_caching_proc using_gnat_llvm {} {
+    # Whether or not gnatmake will use LLVM can't be determined from
+    # the command line -- e.g., --version doesn't provide any
+    # indication.  So for now use a proxy.
+    return [expr {![ada_minimal_encodings]}]
+}
+
 # Return 1 if GNAT supports -Og.
 gdb_caching_proc ada_og {} {
     return [ada_simple_compile gnat_og additional_flags=-Og]