[clang] [PassBuilder] Add a mechanism for adding passbuilder callbacks for static builds (PR #70171)

[William Moses via cfe-commits]

https://github.com/wsmoses updated https://github.com/llvm/llvm-project/pull/70171

>From bb04e157dcd667b9baf261f07f8081a52c5481a0 Mon Sep 17 00:00:00 2001
From: "William S. Moses" <gh at wsmoses.com>
Date: Wed, 25 Oct 2023 02:10:32 -0500
Subject: [PATCH] [Clang] Add codegen option to add passbuilder callback
 functions

---
 clang/include/clang/Basic/CodeGenOptions.h | 6 ++++++
 clang/lib/CodeGen/BackendUtil.cpp          | 3 +++
 2 files changed, 9 insertions(+)

diff --git a/clang/include/clang/Basic/CodeGenOptions.h b/clang/include/clang/Basic/CodeGenOptions.h
index 12be4e0025a7054..c8e2544f891cc2b 100644
--- a/clang/include/clang/Basic/CodeGenOptions.h
+++ b/clang/include/clang/Basic/CodeGenOptions.h
@@ -26,6 +26,9 @@
 #include <string>
 #include <vector>
 
+namespace llvm {
+class PassBuilder;
+}
 namespace clang {
 
 /// Bitfields of CodeGenOptions, split out from CodeGenOptions to ensure
@@ -408,6 +411,9 @@ class CodeGenOptions : public CodeGenOptionsBase {
   /// List of dynamic shared object files to be loaded as pass plugins.
   std::vector<std::string> PassPlugins;
 
+  /// List of pass builder callbacks.
+  std::vector<std::function<void(llvm::PassBuilder &)>> PassBuilderCallbacks;
+
   /// Path to allowlist file specifying which objects
   /// (files, functions) should exclusively be instrumented
   /// by sanitizer coverage pass.
diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index 70accce456d3c07..a8db38fce6425fb 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -906,6 +906,9 @@ void EmitAssemblyHelper::RunOptimizationPipeline(
           << PluginFN << toString(PassPlugin.takeError());
     }
   }
+  for (auto PassCallback : CodeGenOpts.PassBuilderCallbacks) {
+    PassCallback(PB);
+  }
 #define HANDLE_EXTENSION(Ext)                                                  \
   get##Ext##PluginInfo().RegisterPassBuilderCallbacks(PB);
 #include "llvm/Support/Extension.def"