[clang-tools-extra] [clangd] Support .clangd command line modifications for C++ modules (PR #122606)

[kadir çetinkaya via cfe-commits]

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@@ -39,7 +40,25 @@ class MockDirectoryCompilationDatabase : public MockCompilationDatabase {
   void addFile(llvm::StringRef Path, llvm::StringRef Contents);
 
   std::unique_ptr<ProjectModules> getProjectModules(PathRef) const override {
-    return scanningProjectModules(MockedCDBPtr, TFS);
+    auto Modules = scanningProjectModules(MockedCDBPtr, TFS);
+    Modules->setCommandProvider(
+        [this](tooling::CompileCommand &Command, PathRef) {
+          for (auto &Flag : ExcludeFlags) {
+            auto const It = std::find(Command.CommandLine.begin(),
+                                      Command.CommandLine.end(), Flag);
+            if (It != Command.CommandLine.end())
+              Command.CommandLine.erase(It);
+          }
+        });
+    return Modules;
+  }
+
+  void addExtraClangFlag(std::string Flag) {
+    this->ExtraClangFlags.push_back(std::move(Flag));
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kadircet wrote:

`ExtraClangFlags` are already public, you can directly update them un the relevant tests.

https://github.com/llvm/llvm-project/pull/122606