[clang-tidy] New option to remove arguments from the command line

When using clang-tidy from a compilation database, some options might not be
recognized by clang if the compilation database was generated for another compiler.
This forces the user to add conditional code in their CMakeLists.txt to remove
those arguments when using clang-tidy.
A new option was added to the .clang-tidy config to remove
those unknown flags without the need to generate a second compilation_commands.json

Fixes #108455

Author: felix642

clang-tools-extra/clang-tidy/ClangTidy.cpp

@@ -552,6 +552,30 @@ runClangTidy(clang::tidy::ClangTidyContext &Context,
         return AdjustedArgs;
       };
 
+  // Remove unwanted arguments passed to the compiler
+  ArgumentsAdjuster CompilationArgsToIgnore =
+      [&Context](const CommandLineArguments &Args, StringRef Filename) {
+        ClangTidyOptions Opts = Context.getOptionsForFile(Filename);
+        CommandLineArguments AdjustedArgs = Args;
+
+        if (Opts.CompilationArgsToRemoveRegex) {
+          for (StringRef ArgToIgnore : *Opts.CompilationArgsToRemoveRegex) {
+            llvm::Regex ArgToIgnoreRegex(ArgToIgnore);
+            AdjustedArgs.erase(
+                std::remove_if(AdjustedArgs.begin(), AdjustedArgs.end(),
+                               [&](llvm::StringRef Arg) {
+                                 return Arg.starts_with("-") &&
+                                        Arg != "-fsyntax-only" &&
+                                        ArgToIgnoreRegex.match(Arg);
+                               }),
+                AdjustedArgs.end());
+          }
+        }
+
+        return AdjustedArgs;
+      };
+
+  Tool.appendArgumentsAdjuster(CompilationArgsToIgnore);
   Tool.appendArgumentsAdjuster(PerFileExtraArgumentsInserter);
   Tool.appendArgumentsAdjuster(getStripPluginsAdjuster());
   Context.setEnableProfiling(EnableCheckProfile);

clang-tools-extra/clang-tidy/ClangTidyOptions.cpp

@@ -174,6 +174,8 @@ template <> struct MappingTraits<ClangTidyOptions> {
                    Options.ExcludeHeaderFilterRegex);
     IO.mapOptional("FormatStyle", Options.FormatStyle);
     IO.mapOptional("User", Options.User);
+    IO.mapOptional("CompilationArgsToRemoveRegex",
+                   Options.CompilationArgsToRemoveRegex);
     IO.mapOptional("CheckOptions", Options.CheckOptions);
     IO.mapOptional("ExtraArgs", Options.ExtraArgs);
     IO.mapOptional("ExtraArgsBefore", Options.ExtraArgsBefore);
@@ -198,6 +200,7 @@ ClangTidyOptions ClangTidyOptions::getDefaults() {
   Options.SystemHeaders = false;
   Options.FormatStyle = "none";
   Options.User = std::nullopt;
+  Options.CompilationArgsToRemoveRegex = std::nullopt;
   for (const ClangTidyModuleRegistry::entry &Module :
        ClangTidyModuleRegistry::entries())
     Options.mergeWith(Module.instantiate()->getModuleOptions(), 0);
@@ -238,6 +241,8 @@ ClangTidyOptions &ClangTidyOptions::mergeWith(const ClangTidyOptions &Other,
   overrideValue(SystemHeaders, Other.SystemHeaders);
   overrideValue(FormatStyle, Other.FormatStyle);
   overrideValue(User, Other.User);
+  overrideValue(CompilationArgsToRemoveRegex,
+                Other.CompilationArgsToRemoveRegex);
   overrideValue(UseColor, Other.UseColor);
   mergeVectors(ExtraArgs, Other.ExtraArgs);
   mergeVectors(ExtraArgsBefore, Other.ExtraArgsBefore);

clang-tools-extra/clang-tidy/ClangTidyOptions.h

@@ -110,6 +110,10 @@ struct ClangTidyOptions {
   /// comments in the relevant check.
   std::optional<std::string> User;
 
+  /// \brief Remove command line arguments sent to the compiler matching this
+  /// regex.
+  std::optional<std::vector<std::string>> CompilationArgsToRemoveRegex;
+
   /// Helper structure for storing option value with priority of the value.
   struct ClangTidyValue {
     ClangTidyValue() = default;

clang-tools-extra/docs/ReleaseNotes.rst

@@ -106,6 +106,9 @@ Improvements to clang-tidy
 - Improved :program:`run-clang-tidy.py` script. Fixed minor shutdown noise
   happening on certain platforms when interrupting the script.
 
+- Improved :program:`clang-tidy` by adding the option `CompilationArgsToRemoveRegex`
+  to remove arguments sent to the compiler when invoking clang-tidy.
+
 New checks
 ^^^^^^^^^^
 

clang-tools-extra/docs/clang-tidy/index.rst

@@ -303,6 +303,8 @@ An overview of all the command-line options:
                                    example, to place the correct user name in
                                    TODO() comments in the relevant check.
     WarningsAsErrors             - Same as '--warnings-as-errors'.
+    CompilationArgsToRemoveRegex - List of arguments to remove from the command
+                                   line sent to the compiler.
 
     The effective configuration can be inspected using --dump-config:
 
@@ -312,6 +314,7 @@ An overview of all the command-line options:
       WarningsAsErrors:    ''
       HeaderFileExtensions:         ['', 'h','hh','hpp','hxx']
       ImplementationFileExtensions: ['c','cc','cpp','cxx']
+      CompilationArgsToRemoveRegex: ['-Werror', '-f.*']
       HeaderFilterRegex:   ''
       FormatStyle:         none
       InheritParentConfig: true

clang-tools-extra/test/clang-tidy/infrastructure/compilation-args-to-ignore.cpp

@@ -0,0 +1,9 @@
+// RUN: not clang-tidy %s -- -fnot-an-option | FileCheck %s -check-prefix=INVALID-A
+// RUN: clang-tidy %s --config="{CompilationArgsToRemoveRegex: ['-fnot-an-option']}" -- -fnot-an-option
+// RUN: not clang-tidy %s --config="{CompilationArgsToRemoveRegex: ['-f.*']}" -- -fnot-an-option -invalid-option | FileCheck %s -check-prefix=INVALID-B
+// RUN: clang-tidy %s --config="{CompilationArgsToRemoveRegex: ['-f.*', '-invalid-option']}" -- -fnot-an-option -fnot-another-option -finvalid-option -invalid-option
+// RUN: not clang-tidy %s --config="{CompilationArgsToRemoveRegex: ['\$invalid-option']}" -- -finvalid-option | FileCheck %s -check-prefix=INVALID-C
+
+// INVALID-A: error: unknown argument: '-fnot-an-option' [clang-diagnostic-error]
+// INVALID-B: error: unknown argument: '-invalid-option' [clang-diagnostic-error]
+// INVALID-C: error: unknown argument: '-finvalid-option' [clang-diagnostic-error]