Author: Sam McCall Date: 2022-05-09T15:33:31+02:00 New Revision: f1a9c4b717be9a9a730f837dfd70df69d1daf44f
URL: https://github.com/llvm/llvm-project/commit/f1a9c4b717be9a9a730f837dfd70df69d1daf44f DIFF: https://github.com/llvm/llvm-project/commit/f1a9c4b717be9a9a730f837dfd70df69d1daf44f.diff LOG: [clangd] Skip (most) predefined macros when scanning for preamble patching. This is unneccesary work. With this change, we skip generating and lexing ~10k of predefines twice. A dumb benchmark of building a preamble for an empty file in a loop shows: - before: 1.90ms/run - after: 1.36ms/run So this should be worth 0.5ms for each AST build and code completion. There can be a functional difference, but it's very minor. If the preamble contains e.g. `#ifndef __llvm__ ... #endif` then before we would not take it. After this change we will take the branch (single-file mode takes all branches with unknown conditions) and so gather different directives. However I think this is negligible: - this is already true of non-builtin macros (from included headers). We've had no complaints. - this affects the baseline and modified in the same way, so only makes a difference transiently when code guarded by such an #ifdef is being edited Differential Revision: https://reviews.llvm.org/D125179 Added: Modified: clang-tools-extra/clangd/Preamble.cpp Removed: ################################################################################ diff --git a/clang-tools-extra/clangd/Preamble.cpp b/clang-tools-extra/clangd/Preamble.cpp index 5ecd6f3a0bdf..81d7c463ed7a 100644 --- a/clang-tools-extra/clangd/Preamble.cpp +++ b/clang-tools-extra/clangd/Preamble.cpp @@ -302,6 +302,7 @@ scanPreamble(llvm::StringRef Contents, const tooling::CompileCommand &Cmd) { return error("compiler instance had no inputs"); // We are only interested in main file includes. Clang->getPreprocessorOpts().SingleFileParseMode = true; + Clang->getPreprocessorOpts().UsePredefines = false; PreprocessOnlyAction Action; if (!Action.BeginSourceFile(*Clang, Clang->getFrontendOpts().Inputs[0])) return error("failed BeginSourceFile"); _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
