[Clang] Load pass plugins before parsing LLVM options

clang/include/clang/Basic/CodeGenOptions.h

@@ -32,6 +32,7 @@
 
 namespace llvm {
 class PassBuilder;
+class PassPlugin;
 }
 namespace clang {
 
@@ -474,8 +475,11 @@ class CodeGenOptions : public CodeGenOptionsBase {
 
   std::vector<std::string> DefaultFunctionAttrs;
 
-  /// List of dynamic shared object files to be loaded as pass plugins.
-  std::vector<std::string> PassPlugins;
+  /// List of dynamic shared object file names to be loaded as pass plugins.
+  std::vector<std::string> PassPluginNames;
+
+  /// List of loaded pass plugins.
+  std::vector<llvm::PassPlugin *> PassPlugins;
 
   /// List of pass builder callbacks.
   std::vector<std::function<void(llvm::PassBuilder &)>> PassBuilderCallbacks;

clang/include/clang/Options/Options.td

@@ -4072,7 +4072,7 @@ def fpass_plugin_EQ : Joined<["-"], "fpass-plugin=">,
   Group<f_Group>, Visibility<[ClangOption, CC1Option, FlangOption, FC1Option]>,
   MetaVarName<"<dsopath>">, Flags<[NoArgumentUnused]>,
   HelpText<"Load pass plugin from a dynamic shared object file (only with new pass manager).">,
-  MarshallingInfoStringVector<CodeGenOpts<"PassPlugins">>;
+  MarshallingInfoStringVector<CodeGenOpts<"PassPluginNames">>;
 defm tocdata : BoolOption<"m","tocdata",
   CodeGenOpts<"AllTocData">, DefaultFalse,
   PosFlag<SetTrue, [], [ClangOption, CC1Option],

clang/lib/CodeGen/BackendUtil.cpp

@@ -1017,16 +1017,9 @@ void EmitAssemblyHelper::RunOptimizationPipeline(
     }
 #endif
   }
-  // Attempt to load pass plugins and register their callbacks with PB.
-  for (auto &PluginFN : CodeGenOpts.PassPlugins) {
-    auto PassPlugin = PassPlugin::Load(PluginFN);
-    if (PassPlugin) {
-      PassPlugin->registerPassBuilderCallbacks(PB);
-    } else {
-      Diags.Report(diag::err_fe_unable_to_load_plugin)
-          << PluginFN << toString(PassPlugin.takeError());
-    }
-  }
+  // Register plugin callbacks with PB.
+  for (llvm::PassPlugin *Plugin : CodeGenOpts.PassPlugins)
+    Plugin->registerPassBuilderCallbacks(PB);
   for (const auto &PassCallback : CodeGenOpts.PassBuilderCallbacks)
     PassCallback(PB);
 #define HANDLE_EXTENSION(Ext)                                                  \

clang/lib/Frontend/CompilerInstance.cpp

@@ -46,6 +46,7 @@
 #include "llvm/ADT/ScopeExit.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Config/llvm-config.h"
+#include "llvm/Passes/PassPlugin.h"
 #include "llvm/Support/AdvisoryLock.h"
 #include "llvm/Support/BuryPointer.h"
 #include "llvm/Support/CrashRecoveryContext.h"

clang/lib/FrontendTool/CMakeLists.txt

@@ -1,5 +1,6 @@
 set(LLVM_LINK_COMPONENTS
   Option
+  Passes
   Support
   )
 

clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp

@@ -26,6 +26,7 @@
 #include "clang/StaticAnalyzer/Frontend/AnalyzerHelpFlags.h"
 #include "clang/StaticAnalyzer/Frontend/FrontendActions.h"
 #include "llvm/Option/OptTable.h"
+#include "llvm/Passes/PassPlugin.h"
 #include "llvm/Support/BuryPointer.h"
 #include "llvm/Support/DynamicLibrary.h"
 #include "llvm/Support/ErrorHandling.h"
@@ -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().PassPluginNames) {
+    if (auto PassPlugin = llvm::PassPlugin::Load(Path)) {
+      PassPlugins.emplace_back(std::make_unique<llvm::PassPlugin>(*PassPlugin));
+      Clang->getCodeGenOpts().PassPlugins.push_back(PassPlugins.back().get());
+    } else {
+      Clang->getDiagnostics().Report(diag::err_fe_unable_to_load_plugin)
+          << Path << toString(PassPlugin.takeError());
+    }
+  }
+
   // Honor -mllvm.
   //
   // FIXME: Remove this, one day.

clang/test/CMakeLists.txt

@@ -134,6 +134,12 @@ if(CLANG_BUILD_EXAMPLES AND CLANG_PLUGIN_SUPPORT)
     )
 endif ()
 
+if(LLVM_BUILD_EXAMPLES AND NOT WIN32)
+  list(APPEND CLANG_TEST_DEPS
+    Bye
+    )
+endif()
+
 if(LLVM_INCLUDE_SPIRV_TOOLS_TESTS)
   list(APPEND CLANG_TEST_DEPS
     spirv-dis

clang/test/CodeGen/pass-plugins.c

@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 -S < %s -fpass-plugin=%llvmshlibdir/Bye%pluginext -O2 2>&1 | FileCheck %s --check-prefix=CHECK-INACTIVE
+// RUN: %clang_cc1 -S < %s -fpass-plugin=%llvmshlibdir/Bye%pluginext -O2 -mllvm -wave-goodbye 2>&1 | FileCheck %s --check-prefix=CHECK-ACTIVE
+// REQUIRES: plugins, llvm-examples
+// UNSUPPORTED: target={{.*windows.*}}
+// CHECK-INACTIVE-NOT: Bye
+// CHECK-ACTIVE: Bye
+
+int f(int x) {
+  return x;
+}

clang/test/lit.cfg.py

@@ -126,6 +126,8 @@
 
 if config.clang_examples:
     config.available_features.add("examples")
+if config.llvm_examples:
+    config.available_features.add("llvm-examples")
 
 
 def have_host_out_of_process_jit_feature_support():

clang/test/lit.site.cfg.py.in

@@ -28,6 +28,7 @@ config.clang_staticanalyzer_z3 = @LLVM_WITH_Z3@
 config.clang_staticanalyzer_z3_mock = @TEST_WITH_Z3_MOCK@
 config.clang_enable_cir = @CLANG_ENABLE_CIR@
 config.clang_examples = @CLANG_BUILD_EXAMPLES@
+config.llvm_examples = @LLVM_BUILD_EXAMPLES@
 config.enable_shared = @ENABLE_SHARED@
 config.enable_backtrace = @ENABLE_BACKTRACES@
 config.enable_threads = @LLVM_ENABLE_THREADS@