[debug-info][XCOFF] set `-gno-column-info` by default for DBX

[shchenz]

Summary

For DBX, it does not handle column info well. Set -gno-column-info by default for DBX.

[dblaikie]

Sounds good to me

clang/lib/Driver/ToolChains/Clang.cpp

3976

[shchenz]

clang/lib/Driver/ToolChains/Clang.cpp

3976

oops. Will fix in the commit.

clang/lib/Driver/ToolChains/Clang.cpp

static void renderDebugOptions(const ToolChain &TC, const Driver &D,
 
   // We ignore flag -gstrict-dwarf for now.
   // And we handle flag -grecord-gcc-switches later with DWARFDebugFlags.
   Args.ClaimAllArgs(options::OPT_g_flags_Group);
 
   // Column info is included by default for everything except SCE and
   // CodeView. Clang doesn't track end columns, just starting columns, which,
   // in theory, is fine for CodeView (and PDB).  In practice, however, the
-  // Microsoft debuggers don't handle missing end columns well, so it's better
-  // not to include any column info.
+  // Microsoft debuggers don't handle missing end columns well, and the AIX
+  // debugger DBX also doesn't handle the columns well, so it's better not to
+  // include any column info.
   if (const Arg *A = Args.getLastArg(options::OPT_gcolumn_info))
     (void)checkDebugInfoOption(A, Args, D, TC);
   if (!Args.hasFlag(options::OPT_gcolumn_info, options::OPT_gno_column_info,
-                    !EmitCodeView && DebuggerTuning != llvm::DebuggerKind::SCE))
+                    !EmitCodeView &&
+                        (DebuggerTuning != llvm::DebuggerKind::SCE &&
+                         DebuggerTuning != llvm::DebuggerKind::DBX)))
     CmdArgs.push_back("-gno-column-info");
 
   // FIXME: Move backend command line options to the module.
   // If -gline-tables-only or -gline-directives-only is the last option it wins.
   if (const Arg *A = Args.getLastArg(options::OPT_gmodules))
     if (checkDebugInfoOption(A, Args, D, TC)) {
       if (DebugInfoKind != codegenoptions::DebugLineTablesOnly &&
           DebugInfoKind != codegenoptions::DebugDirectivesOnly) {

clang/test/Driver/debug-options.c

 // RUN:             | FileCheck -check-prefix=NOCI %s
 
 // On the AIX, -g defaults to -gdbx and limited debug info.
 // RUN: %clang -### -c -g %s -target powerpc-ibm-aix-xcoff 2>&1 \
 // RUN:             | FileCheck -check-prefix=G_LIMITED -check-prefix=G_DBX %s
 // RUN: %clang -### -c -g %s -target powerpc64-ibm-aix-xcoff 2>&1 \
 // RUN:             | FileCheck -check-prefix=G_LIMITED -check-prefix=G_DBX %s
 
+// On the AIX, -g defaults to -gno-column-info.
+// RUN: %clang -### -c -g %s -target powerpc-ibm-aix-xcoff 2>&1 \
+// RUN:             | FileCheck -check-prefix=NOCI %s
+// RUN: %clang -### -c -g %s -target powerpc64-ibm-aix-xcoff 2>&1 \
+// RUN:             | FileCheck -check-prefix=NOCI %s
+// RUN: %clang -### -c -g %s -target powerpc-ibm-aix-xcoff -gcolumn-info 2>&1 \
+// RUN:             | FileCheck -check-prefix=CI %s
+// RUN: %clang -### -c -g %s -target powerpc64-ibm-aix-xcoff -gcolumn-info \
+// RUN:             2>&1 | FileCheck -check-prefix=CI %s
+
 // RUN: %clang -### -c -gdwarf-2 %s 2>&1 \
 // RUN:             | FileCheck -check-prefix=G_ONLY_DWARF2 %s
 //
 // RUN: not %clang -### -c -gfoo %s 2>&1 | FileCheck -check-prefix=G_ERR %s
 // RUN: %clang -### -c -g -g0 %s 2>&1 | FileCheck -check-prefix=G_NO %s
 // RUN: %clang -### -c -ggdb0 %s 2>&1 | FileCheck -check-prefix=G_NO %s
 // RUN: %clang -### -c -glldb -g0 %s 2>&1 | FileCheck -check-prefix=G_NO %s
 // RUN: %clang -### -c -glldb -g1 %s 2>&1 \