[clang] 587729c - [clang] [Driver] Add an option to disable default config filenames

[Michał Górny via cfe-commits]

Author: Michał Górny
Date: 2022-09-16T19:38:11+02:00
New Revision: 587729c3ad78aec6ec5a295331b16f21e340feb1

URL: https://github.com/llvm/llvm-project/commit/587729c3ad78aec6ec5a295331b16f21e340feb1
DIFF: https://github.com/llvm/llvm-project/commit/587729c3ad78aec6ec5a295331b16f21e340feb1.diff

LOG: [clang] [Driver] Add an option to disable default config filenames

Add a `--no-default-config` option that disables the search for default
set of config filenames (based on the compiler executable name).

Suggested in https://discourse.llvm.org/t/rfc-adding-a-default-file-location-to-config-file-support/63606.

Differential Revision: https://reviews.llvm.org/D134018

Added: 
    

Modified: 
    clang/docs/UsersManual.rst
    clang/include/clang/Driver/Options.td
    clang/lib/Driver/Driver.cpp
    clang/test/Driver/config-file3.c

Removed: 
    


################################################################################
diff  --git a/clang/docs/UsersManual.rst b/clang/docs/UsersManual.rst
index bc107be41fab8..9eb2e0dbb1e2e 100644
--- a/clang/docs/UsersManual.rst
+++ b/clang/docs/UsersManual.rst
@@ -904,6 +904,10 @@ clang build using CMake parameters, CLANG_CONFIG_FILE_USER_DIR and
 CLANG_CONFIG_FILE_SYSTEM_DIR respectively. The first file found is used. It is
 an error if the required file cannot be found.
 
+If no explicit configuration file is specified, Clang searches for a default
+configuration file following the rules described in the next paragraphs.
+To disable this behavior, `--no-default-config` flag can be used.
+
 Another way to specify a configuration file is to encode it in executable name.
 For example, if the Clang executable is named `armv7l-clang` (it may be a
 symbolic link to `clang`), then Clang will search for file `armv7l.cfg` in the

diff  --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index a1071294ff6f5..8dea1a01c1f89 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -901,6 +901,8 @@ def combine : Flag<["-", "--"], "combine">, Flags<[NoXarchOption, Unsupported]>;
 def compatibility__version : JoinedOrSeparate<["-"], "compatibility_version">;
 def config : Separate<["--"], "config">, Flags<[NoXarchOption]>,
   HelpText<"Specifies configuration file">;
+def no_default_config : Flag<["--"], "no-default-config">, Flags<[NoXarchOption]>,
+  HelpText<"Disable loading default configuration files">;
 def config_system_dir_EQ : Joined<["--"], "config-system-dir=">, Flags<[NoXarchOption, HelpHidden]>,
   HelpText<"System directory for configuration files">;
 def config_user_dir_EQ : Joined<["--"], "config-user-dir=">, Flags<[NoXarchOption, HelpHidden]>,

diff  --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index 217236f459a50..d8b13730f5885 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -1024,11 +1024,14 @@ bool Driver::loadConfigFile() {
     }
   }
 
-  // If config file is not specified explicitly, try to deduce configuration
-  // from executable name. For instance, an executable 'armv7l-clang' will
-  // search for config file 'armv7l-clang.cfg'.
-  if (CfgFileName.empty() && !ClangNameParts.TargetPrefix.empty())
-    CfgFileName = ClangNameParts.TargetPrefix + '-' + ClangNameParts.ModeSuffix;
+  if (!(CLOptions && CLOptions->hasArg(options::OPT_no_default_config))) {
+    // If config file is not specified explicitly, try to deduce configuration
+    // from executable name. For instance, an executable 'armv7l-clang' will
+    // search for config file 'armv7l-clang.cfg'.
+    if (CfgFileName.empty() && !ClangNameParts.TargetPrefix.empty())
+      CfgFileName =
+          ClangNameParts.TargetPrefix + '-' + ClangNameParts.ModeSuffix;
+  }
 
   if (CfgFileName.empty())
     return false;

diff  --git a/clang/test/Driver/config-file3.c b/clang/test/Driver/config-file3.c
index 8efe1e555a3c8..7fdc2a59133a8 100644
--- a/clang/test/Driver/config-file3.c
+++ b/clang/test/Driver/config-file3.c
@@ -40,7 +40,13 @@
 // RUN: %t/testdmode/qqq-clang-g++ --config-system-dir=%S/Inputs/config --config-user-dir= --config i386-qqq -c -no-canonical-prefixes -### %s 2>&1 | FileCheck %s -check-prefix CHECK-EXPLICIT
 //
 // CHECK-EXPLICIT: Configuration file: {{.*}}/Inputs/config/i386-qqq.cfg
+
+//--- --no-default-config disables config search.
+//
+// RUN: %t/testdmode/qqq-clang-g++ --config-system-dir= --config-user-dir=%t/testdmode --no-default-config -c -### %s 2>&1 | FileCheck %s -check-prefix NO-DEFAULT-CONFIG
 //
+// NO-DEFAULT-CONFIG-NOT: Configuration file:
+
 //--- Invocation qqq-clang-g++ tries to find config file qqq.cfg if qqq-clang-g++.cfg is not found.
 //
 // RUN: rm %t/testdmode/qqq-clang-g++.cfg