[clangd] Use CommandMangler in TestTU

[kadircet]

Summary

This makes testing setup look closer to production.

[sammccall]

I guess this is technically untested, but will be covered after D106527?

[kadircet]

yes that's right.

[thakis]

One of your 4 commits in https://github.com/llvm/llvm-project/compare/f86570cd5241...ba5dd945ad91 broke check-clangd on arm macs:

http://45.33.8.238/macm1/14648/step_9.txt

Please take a look, and revert for now if it takes a while to fix. (And consider spreading out commits a bit, so it's clearer which one is to blame.)

[MaskRay]

[clangd] Get rid of arg adjusters in CommandMangler can crash BuildCompilerInvocation.DropsPlugins.

I am testing ninja check-clangd and will push the revert shortly.

[kadircet]

Can you provide a reproducer or build bot failure for the crash Fangrui ?

[MaskRay]

In D106535#2900728, @kadircet wrote:

Can you provide a reproducer or build bot failure for the crash Fangrui ?

I already provided an internal bug :)

clang-tools-extra/clangd/unittests/TestTU.cpp

 //===--- TestTU.cpp - Scratch source files for testing --------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #include "TestTU.h"
+#include "CompileCommands.h"
 #include "Compiler.h"
 #include "Diagnostics.h"
 #include "TestFS.h"
 #include "index/FileIndex.h"
 #include "index/MemIndex.h"
 #include "clang/AST/RecursiveASTVisitor.h"
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Frontend/CompilerInvocation.h"
if (!HeaderCode.empty()) {
     // The default is OS-dependent (on on windows), ensure it's off.
     if (ImplicitHeaderGuard)
       Inputs.CompileCommand.CommandLine.push_back("-fno-ms-compatibility");
   }
   Argv.insert(Argv.end(), ExtraArgs.begin(), ExtraArgs.end());
   // Put the file name at the end -- this allows the extra arg (-xc++) to
   // override the language setting.
   Argv.push_back(FullFilename);
+
+  auto Mangler = CommandMangler::forTests();
+  Mangler.adjust(Inputs.CompileCommand.CommandLine);
   Inputs.CompileCommand.Filename = FullFilename;
   Inputs.CompileCommand.Directory = testRoot();
   Inputs.Contents = Code;
   if (OverlayRealFileSystemForModules)
     FS.OverlayRealFileSystemForModules = true;
   Inputs.TFS = &FS;
   Inputs.Opts = ParseOptions();
   if (ClangTidyProvider)

clang/lib/Frontend/CreateInvocationFromCommandLine.cpp

 //===--- CreateInvocationFromCommandLine.cpp - CompilerInvocation from Args ==//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
 // Construct a compiler invocation object for command line driver arguments
 //
 //===----------------------------------------------------------------------===//
 
-#include "clang/Frontend/Utils.h"
 #include "clang/Basic/DiagnosticOptions.h"
+#include "clang/Driver/Action.h"
 #include "clang/Driver/Compilation.h"
 #include "clang/Driver/Driver.h"
-#include "clang/Driver/Action.h"
 #include "clang/Driver/Options.h"
 #include "clang/Driver/Tool.h"
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Frontend/FrontendDiagnostic.h"
+#include "clang/Frontend/Utils.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/StringRef.h"
 #include "llvm/Option/ArgList.h"
 #include "llvm/Support/Host.h"
 using namespace clang;
 using namespace llvm::opt;
 
 std::unique_ptr<CompilerInvocation> clang::createInvocationFromCommandLine(
     ArrayRef<const char *> ArgList, IntrusiveRefCntPtr<DiagnosticsEngine> Diags,
     IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS, bool ShouldRecoverOnErorrs,
     std::vector<std::string> *CC1Args) {
   if (!Diags.get()) {
     // No diagnostics engine was provided, so create our own diagnostics object
     // with the default options.
     Diags = CompilerInstance::createDiagnostics(new DiagnosticOptions);
   }
 
   SmallVector<const char *, 16> Args(ArgList.begin(), ArgList.end());
 
   // FIXME: Find a cleaner way to force the driver into restricted modes.
-  Args.push_back("-fsyntax-only");
+  Args.insert(
+      llvm::find_if(
+          Args, [](const char *Elem) { return llvm::StringRef(Elem) == "--"; }),
+      "-fsyntax-only");
 
   // FIXME: We shouldn't have to pass in the path info.
   driver::Driver TheDriver(Args[0], llvm::sys::getDefaultTargetTriple(), *Diags,
                            "clang LLVM compiler", VFS);
 
   // Don't check that inputs exist, they may have been remapped.
   TheDriver.setCheckInputsExist(false);