[CLANG][DWARF] Do not emit -ggnu-pubnames for LLDB tuning, unless -ggnu-pubnames is specified. (#83331)

When -gsplit-dwarf is passed in clang emmmits -ggnu-pubnames which
results in
.debug_gnu_pubnames/..debug_gnu_pubtypes being generated.
This is used by GDB, but not by LLDB.
Changed so that these sections are not emitted for LLDB tuning, unless
flag
is passed explicitly.

Author: ayermolo

clang/lib/Driver/ToolChains/Clang.cpp

@@ -4478,14 +4478,20 @@ renderDebugOptions(const ToolChain &TC, const Driver &D, const llvm::Triple &T,
       Args.getLastArg(options::OPT_ggnu_pubnames, options::OPT_gno_gnu_pubnames,
                       options::OPT_gpubnames, options::OPT_gno_pubnames);
   if (DwarfFission != DwarfFissionKind::None ||
-      (PubnamesArg && checkDebugInfoOption(PubnamesArg, Args, D, TC)))
-    if (!PubnamesArg ||
-        (!PubnamesArg->getOption().matches(options::OPT_gno_gnu_pubnames) &&
-         !PubnamesArg->getOption().matches(options::OPT_gno_pubnames)))
+      (PubnamesArg && checkDebugInfoOption(PubnamesArg, Args, D, TC))) {
+    const bool OptionSet =
+        (PubnamesArg &&
+         (PubnamesArg->getOption().matches(options::OPT_gpubnames) ||
+          PubnamesArg->getOption().matches(options::OPT_ggnu_pubnames)));
+    if ((DebuggerTuning != llvm::DebuggerKind::LLDB || OptionSet) &&
+        (!PubnamesArg ||
+         (!PubnamesArg->getOption().matches(options::OPT_gno_gnu_pubnames) &&
+          !PubnamesArg->getOption().matches(options::OPT_gno_pubnames))))
       CmdArgs.push_back(PubnamesArg && PubnamesArg->getOption().matches(
                                            options::OPT_gpubnames)
                             ? "-gpubnames"
                             : "-ggnu-pubnames");
+  }
   const auto *SimpleTemplateNamesArg =
       Args.getLastArg(options::OPT_gsimple_template_names,
                       options::OPT_gno_simple_template_names);

clang/test/Driver/split-debug.c

@@ -124,3 +124,13 @@
 // G1_NOSPLIT: "-debug-info-kind=line-tables-only"
 // G1_NOSPLIT-NOT: "-split-dwarf-file"
 // G1_NOSPLIT-NOT: "-split-dwarf-output"
+
+/// Do not generate -ggnu-pubnames for -glldb
+// RUN: %clang -### -c -target x86_64 -gsplit-dwarf -g -glldb %s 2>&1 | FileCheck %s --check-prefixes=GLLDBSPLIT
+
+// GLLDBSPLIT-NOT: "-ggnu-pubnames"
+
+/// Generate -ggnu-pubnames for -glldb when it is explicitly enabled
+// RUN: %clang -### -c -target x86_64 -gsplit-dwarf -g -glldb -ggnu-pubnames %s 2>&1 | FileCheck %s --check-prefixes=GLLDBSPLIT2
+
+// GLLDBSPLIT2: "-ggnu-pubnames"