[clang-tidy] support parameters file in command line

clang-tools-extra/clang-tidy/tool/ClangTidyMain.cpp

@@ -20,12 +20,14 @@
 #include "../GlobList.h"
 #include "clang/Tooling/CommonOptionsParser.h"
 #include "llvm/ADT/StringSet.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/InitLLVM.h"
 #include "llvm/Support/PluginLoader.h"
 #include "llvm/Support/Process.h"
 #include "llvm/Support/Signals.h"
 #include "llvm/Support/TargetSelect.h"
 #include "llvm/Support/WithColor.h"
+#include "llvm/TargetParser/Host.h"
 #include <optional>
 
 using namespace clang::tooling;
@@ -553,6 +555,21 @@ static llvm::IntrusiveRefCntPtr<vfs::OverlayFileSystem> createBaseFS() {
 
 int clangTidyMain(int argc, const char **argv) {
   llvm::InitLLVM X(argc, argv);
+  SmallVector<const char *> Args{argv, argv + argc};
+
+  // expand parameters file to argc and argv.
+  llvm::BumpPtrAllocator Alloc;
+  llvm::cl::TokenizerCallback Tokenizer =
+      llvm::Triple(llvm::sys::getProcessTriple()).isOSWindows()
+          ? llvm::cl::TokenizeWindowsCommandLine
+          : llvm::cl::TokenizeGNUCommandLine;
+  llvm::cl::ExpansionContext ECtx(Alloc, Tokenizer);
+  if (llvm::Error Err = ECtx.expandResponseFiles(Args)) {
+    llvm::WithColor::error() << llvm::toString(std::move(Err)) << "\n";
+    return 1;
+  }
+  argc = static_cast<int>(Args.size());
+  argv = Args.data();
 
   // Enable help for -load option, if plugins are enabled.
   if (cl::Option *LoadOpt = cl::getRegisteredOptions().lookup("load"))

clang-tools-extra/docs/ReleaseNotes.rst

@@ -115,6 +115,8 @@ 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 accepting parameters file in command line.
+
 - Removed :program:`clang-tidy`'s global options for most of checks. All options
   are changed to local options except `IncludeStyle`, `StrictMode` and
   `IgnoreMacros`.

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

@@ -33,6 +33,13 @@ compilation options on the command line after ``--``:
 
   $ clang-tidy test.cpp -- -Imy_project/include -DMY_DEFINES ...
 
+If there are too many options to specify on the command line, you can store them
+in a parameter file, and use :program:`clang-tidy` with parameters file:
+
+.. code-block:: console
+
+  $ clang-tidy @parameters_file
+
 :program:`clang-tidy` has its own checks and can also run Clang Static Analyzer
 checks. Each check has a name and the checks to run can be chosen using the
 ``-checks=`` option, which specifies a comma-separated list of positive and

clang-tools-extra/test/clang-tidy/infrastructure/Inputs/param/parameters.txt

@@ -0,0 +1,2 @@
+-checks='-*,llvm-namespace-comment'
+--warnings-as-errors=llvm-namespace-comment

clang-tools-extra/test/clang-tidy/infrastructure/read-parameters-from-file-error.cpp

@@ -0,0 +1,3 @@
+// RUN: echo @%t.param > %t.param && not clang-tidy %s @%t.param -- 2>&1 | FileCheck %s
+
+// CHECK: recursive expansion of

clang-tools-extra/test/clang-tidy/infrastructure/read-parameters-from-file.cpp

@@ -0,0 +1,5 @@
+// RUN: not clang-tidy %s @%S/Inputs/param/parameters.txt -- | FileCheck %s
+
+namespace i {
+}
+// CHECK: error: namespace 'i' not terminated with a closing comment [llvm-namespace-comment,-warnings-as-errors]