[llvm-branch-commits] [clang] [Clang] Load pass plugins before parsing LLVM options (PR #171868)

[Alexis Engelke via llvm-branch-commits]

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@@ -233,6 +234,20 @@ bool ExecuteCompilerInvocation(CompilerInstance *Clang) {
 
   Clang->LoadRequestedPlugins();
 
+  // Load and store pass plugins for the back-end. Store the loaded pass plugins
+  // here and store references to these in CodeGenOpts to avoid pulling in the
+  // entire PassPlugin dependency chain in CodeGenOpts.
+  std::vector<std::unique_ptr<llvm::PassPlugin>> PassPlugins;
+  for (const std::string &Path : Clang->getCodeGenOpts().PassPlugins) {
+    if (auto PassPlugin = llvm::PassPlugin::Load(Path)) {
+      PassPlugins.emplace_back(std::make_unique<llvm::PassPlugin>(*PassPlugin));
+      Clang->getPassPlugins().push_back(PassPlugins.back().get());
+    } else {
+      Clang->getDiagnostics().Report(diag::err_fe_unable_to_load_plugin)
+          << Path << toString(PassPlugin.takeError());
+    }
+  }
+
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aengelke wrote:

llvm::PassPlugin::Load pulls in the LLVM Passes library, which pulls in almost all passes. I can do that, but then the clangFrontend library would have many more dependencies. clangFrontendTool already pulls these in through CodeGen etc., but clangFrontend users might not want that?

https://github.com/llvm/llvm-project/pull/171868