[clang] Remove -g[no-]-* bool flags from g_Group

[rnk]

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

[llvmbot]

@llvm/pr-subscribers-clang-driver

@llvm/pr-subscribers-clang

Author: Reid Kleckner (rnk)

Changes

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

---

Full diff: https://github.com/llvm/llvm-project/pull/162750.diff

3 Files Affected:

• (modified) clang/include/clang/Driver/Options.td (+5-4)
• (modified) clang/test/DebugInfo/KeyInstructions/flag.cpp (+3)
• (modified) clang/test/Driver/debug-options.c (+3-3)

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

[alexfh]

Not enabling debug info for -gno-... options seems to be the right behavior. One might argue about the positive options, but I think, that's also correct. At least, it's better than the current situation: now the options being changed here override -gmlt with -g, which also doesn't seem intentional.

Looks good with one comment re: "Implies -g."

[alexfh]

Could you remove the "Implies -g." part from the description of the affected options?

[Michael137]

thanks!

[rnk]

Thanks for the review!

[llvm-ci]

LLVM Buildbot has detected a new failure on builder clang-armv8-quick running on linaro-clang-armv8-quick while building clang at step 5 "ninja check 1".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/154/builds/22599

Here is the relevant piece of the build log for the reference

Step 5 (ninja check 1) failure: stage 1 checked (failure)
******************** TEST 'LLVM-Unit :: Support/./SupportTests/163/416' FAILED ********************
Script(shard):
--
GTEST_OUTPUT=json:/home/tcwg-buildbot/worker/clang-armv8-quick/stage1/unittests/Support/./SupportTests-LLVM-Unit-3957403-163-416.json GTEST_SHUFFLE=0 GTEST_TOTAL_SHARDS=416 GTEST_SHARD_INDEX=163 /home/tcwg-buildbot/worker/clang-armv8-quick/stage1/unittests/Support/./SupportTests
--

Script:
--
/home/tcwg-buildbot/worker/clang-armv8-quick/stage1/unittests/Support/./SupportTests --gtest_filter=ProgramEnvTest.TestLockFile
--
../llvm/llvm/unittests/Support/ProgramTest.cpp:571: Failure
Value of: Error.empty()
  Actual: false
Expected: true


../llvm/llvm/unittests/Support/ProgramTest.cpp:571
Value of: Error.empty()
  Actual: false
Expected: true



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