[clangd] allow clients to control the compilation database by passing in

compilationDatabaseChanges in the 'workspace/didChangeConfiguration' request

This commit allows clangd to use an in-memory compilation database that's
controlled from the LSP client (-compile_args_from=lsp). It extends the
'workspace/didChangeConfiguration' request to allow the client to pass in a
compilation database subset that needs to be updated in the workspace.

Differential Revision: https://reviews.llvm.org/D49758

llvm-svn: 338597

1 files changed, 15 insertions, 1 deletions

diff --git a/clang-tools-extra/clangd/tool/ClangdMain.cpp b/clang-tools-extra/clangd/tool/ClangdMain.cpp
index 95ffdfad52e..9e161f5e850 100644
--- a/clang-tools-extra/clangd/tool/ClangdMain.cpp
+++ b/clang-tools-extra/clangd/tool/ClangdMain.cpp
@@ -173,6 +173,18 @@ static llvm::cl::opt<Path> YamlSymbolFile(
         "eventually. Don't rely on it."),
     llvm::cl::init(""), llvm::cl::Hidden);
 
+enum CompileArgsFrom { LSPCompileArgs, FilesystemCompileArgs };
+
+static llvm::cl::opt<CompileArgsFrom> CompileArgsFrom(
+    "compile_args_from", llvm::cl::desc("The source of compile commands"),
+    llvm::cl::values(clEnumValN(LSPCompileArgs, "lsp",
+                                "All compile commands come from LSP and "
+                                "'compile_commands.json' files are ignored"),
+                     clEnumValN(FilesystemCompileArgs, "filesystem",
+                                "All compile commands come from the "
+                                "'compile_commands.json' files")),
+    llvm::cl::init(FilesystemCompileArgs), llvm::cl::Hidden);
+
 int main(int argc, char *argv[]) {
   llvm::sys::PrintStackTraceOnErrorSignal(argv[0]);
   llvm::cl::SetVersionPrinter([](llvm::raw_ostream &OS) {
@@ -289,7 +301,9 @@ int main(int argc, char *argv[]) {
   }
 
   // Initialize and run ClangdLSPServer.
-  ClangdLSPServer LSPServer(Out, CCOpts, CompileCommandsDirPath, Opts);
+  ClangdLSPServer LSPServer(
+      Out, CCOpts, CompileCommandsDirPath,
+      /*ShouldUseInMemoryCDB=*/CompileArgsFrom == LSPCompileArgs, Opts);
   constexpr int NoShutdownRequestErrorCode = 1;
   llvm::set_thread_name("clangd.main");
   // Change stdin to binary to not lose \r\n on windows.