[clang] [clang] Remove -g[no-]-* bool flags from g_Group (PR #162750)

[Reid Kleckner via cfe-commits]

https://github.com/rnk created https://github.com/llvm/llvm-project/pull/162750

There are four uses of BoolGOption, and all of them are essentially debug
info feature flags, which I believe should not the enablement or
disablement of all debug info emission. `OPT_g_group` is used to control
the debug info level here:
https://github.com/llvm/llvm-project/blob/main/clang/lib/Driver/ToolChains/Clang.cpp#L4387

This doesn't cause any test failures, and seems like the right behavior
for all four flags:
* -g[no-]flag-base
* -g[no-]inline-line-tables
* -g[no-]key-instructions
* -g[no-]structor-decl-linkage-names

None of these, even in the positive form, should enable debug info
emission.

Fixes #162747


>From 853d60eb21eb7a56494925021fb608e41b812a61 Mon Sep 17 00:00:00 2001
From: Reid Kleckner <rnk at google.com>
Date: Thu, 9 Oct 2025 22:52:45 +0000
Subject: [PATCH] [clang] Remove -g[no-]-* bool flags from g_Group

There are four uses of BoolGOption, and all of them are essentially debug
info feature flags, which I believe should not the enablement or
disablement of all debug info emission. `OPT_g_group` is used to control
the debug info level here:
https://github.com/llvm/llvm-project/blob/main/clang/lib/Driver/ToolChains/Clang.cpp#L4387

This doesn't cause any test failures, and seems like the right behavior
for all four flags:
* -g[no-]flag-base
* -g[no-]inline-line-tables
* -g[no-]key-instructions
* -g[no-]structor-decl-linkage-names

None of these, even in the positive form, should enable debug info
emission.

Fixes #162747
---
 clang/include/clang/Driver/Options.td         | 9 +++++----
 clang/test/DebugInfo/KeyInstructions/flag.cpp | 3 +++
 clang/test/Driver/debug-options.c             | 6 +++---
 3 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 9bfa1dd52effe..ced6f873516ba 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -545,15 +545,16 @@ multiclass BoolFOption<string flag_base, KeyPathAndMacro kpm,
               Group<f_Group>;
 }
 
-// Creates a BoolOption where both of the flags are prefixed with "g" and have
-// the Group<g_Group>.
+// Creates a BoolOption where both of the flags are prefixed with "g".
+// Does *not* map to g_Group, because that is reserved for flags that are
+// intended to enable (or disable) debug info, which is not appropriate for a
+// negative boolean flag (-gno-${feature}).
 // Used for -cc1 frontend options. Driver-only options do not map to
 // CompilerInvocation.
 multiclass BoolGOption<string flag_base, KeyPathAndMacro kpm,
                        Default default, FlagDef flag1, FlagDef flag2,
                        BothFlags both = BothFlags<[]>> {
-  defm NAME : BoolOption<"g", flag_base, kpm, default, flag1, flag2, both>,
-              Group<g_Group>;
+  defm NAME : BoolOption<"g", flag_base, kpm, default, flag1, flag2, both>;
 }
 
 multiclass BoolMOption<string flag_base, KeyPathAndMacro kpm,
diff --git a/clang/test/DebugInfo/KeyInstructions/flag.cpp b/clang/test/DebugInfo/KeyInstructions/flag.cpp
index a5cd8558eae52..12802c1ccb823 100644
--- a/clang/test/DebugInfo/KeyInstructions/flag.cpp
+++ b/clang/test/DebugInfo/KeyInstructions/flag.cpp
@@ -1,5 +1,6 @@
 // RUN: %clang -### -target x86_64 -c -gdwarf -gkey-instructions %s 2>&1 | FileCheck %s --check-prefixes=KEY-INSTRUCTIONS
 // RUN: %clang -### -target x86_64 -c -gdwarf -gno-key-instructions %s 2>&1 | FileCheck %s --check-prefixes=NO-KEY-INSTRUCTIONS
+// RUN: %clang -### -target x86_64 -c -gno-key-instructions %s 2>&1 | FileCheck %s --check-prefixes=NO-DEBUG
 
 //// Help.
 // RUN %clang --help | FileCheck %s --check-prefix=HELP
@@ -7,6 +8,8 @@
 
 // KEY-INSTRUCTIONS: "-gkey-instructions"
 // NO-KEY-INSTRUCTIONS-NOT: key-instructions
+// NO-DEBUG-NOT: debug-info-kind
+// NO-DEBUG-NOT: dwarf
 
 //// Help hidden: flag should not be visible.
 // RUN: %clang --help | FileCheck %s --check-prefix=HELP
diff --git a/clang/test/Driver/debug-options.c b/clang/test/Driver/debug-options.c
index 73f2f402efa97..45ac450ac8faa 100644
--- a/clang/test/Driver/debug-options.c
+++ b/clang/test/Driver/debug-options.c
@@ -268,11 +268,11 @@
 // RUN: %clang -### -c %s 2>&1 | FileCheck -check-prefix=NORNGBSE %s
 // RUN: %clang -### -c -fdebug-ranges-base-address -fno-debug-ranges-base-address %s 2>&1 | FileCheck -check-prefix=NORNGBSE %s
 //
-// RUN: %clang -### -c -gomit-unreferenced-methods -fno-standalone-debug %s 2>&1 | FileCheck -check-prefix=INCTYPES %s
+// RUN: %clang -### -c -g -gomit-unreferenced-methods -fno-standalone-debug %s 2>&1 | FileCheck -check-prefix=INCTYPES %s
 // RUN: %clang -### -c %s 2>&1 | FileCheck -check-prefix=NOINCTYPES %s
-// RUN: %clang -### -c -gomit-unreferenced-methods -fdebug-types-section -target x86_64-unknown-linux %s 2>&1 \
+// RUN: %clang -### -c -g -gomit-unreferenced-methods -fdebug-types-section -target x86_64-unknown-linux %s 2>&1 \
 // RUN:        | FileCheck -check-prefix=NOINCTYPES %s
-// RUN: %clang -### -c -gomit-unreferenced-methods -fstandalone-debug %s 2>&1 | FileCheck -check-prefix=NOINCTYPES %s
+// RUN: %clang -### -c -g -gomit-unreferenced-methods -fstandalone-debug %s 2>&1 | FileCheck -check-prefix=NOINCTYPES %s
 //
 // RUN: %clang -### -c -glldb %s 2>&1 | FileCheck -check-prefix=NOPUB %s
 // RUN: %clang -### -c -glldb -gno-pubnames %s 2>&1 | FileCheck -check-prefix=NOPUB %s