Enable new passmanager plugin support for LTO.

This should make both static and dynamic NewPM plugins work with LTO.
And as a bonus, it makes static linking of OldPM plugins more reliable
for plugins with both an OldPM and NewPM interface.

I only implemented the command-line flag to specify NewPM plugins in
llvm-lto2, to show it works. Support can be added for other tools later.

Differential Revision: https://reviews.llvm.org/D76866

1 files changed, 31 insertions, 3 deletions

diff --git a/llvm/lib/LTO/LTOBackend.cpp b/llvm/lib/LTO/LTOBackend.cpp
index dbd6f8c..22019e4 100644
--- a/llvm/lib/LTO/LTOBackend.cpp
+++ b/llvm/lib/LTO/LTOBackend.cpp
@@ -28,6 +28,7 @@
 #include "llvm/MC/SubtargetFeature.h"
 #include "llvm/Object/ModuleSymbolTable.h"
 #include "llvm/Passes/PassBuilder.h"
+#include "llvm/Passes/PassPlugin.h"
 #include "llvm/Passes/StandardInstrumentations.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/FileSystem.h"
@@ -127,6 +128,29 @@ Error Config::addSaveTemps(std::string OutputFileName,
   return Error::success();
 }
 
+#define HANDLE_EXTENSION(Ext)                                                  \
+  llvm::PassPluginLibraryInfo get##Ext##PluginInfo();
+#include "llvm/Support/Extension.def"
+
+static void RegisterPassPlugins(ArrayRef<std::string> PassPlugins,
+                                PassBuilder &PB) {
+#define HANDLE_EXTENSION(Ext)                                                  \
+  get##Ext##PluginInfo().RegisterPassBuilderCallbacks(PB);
+#include "llvm/Support/Extension.def"
+
+  // Load requested pass plugins and let them register pass builder callbacks
+  for (auto &PluginFN : PassPlugins) {
+    auto PassPlugin = PassPlugin::Load(PluginFN);
+    if (!PassPlugin) {
+      errs() << "Failed to load passes from '" << PluginFN
+             << "'. Request ignored.\n";
+      continue;
+    }
+
+    PassPlugin->registerPassBuilderCallbacks(PB);
+  }
+}
+
 namespace {
 
 std::unique_ptr<TargetMachine>
@@ -181,6 +205,8 @@ static void runNewPMPasses(const Config &Conf, Module &Mod, TargetMachine *TM,
   if (auto Err = PB.parseAAPipeline(AA, "default"))
     report_fatal_error("Error parsing default AA pipeline");
 
+  RegisterPassPlugins(Conf.PassPlugins, PB);
+
   LoopAnalysisManager LAM(Conf.DebugPassManager);
   FunctionAnalysisManager FAM(Conf.DebugPassManager);
   CGSCCAnalysisManager CGAM(Conf.DebugPassManager);
@@ -228,8 +254,8 @@ static void runNewPMPasses(const Config &Conf, Module &Mod, TargetMachine *TM,
   // FIXME (davide): verify the output.
 }
 
-static void runNewPMCustomPasses(Module &Mod, TargetMachine *TM,
-                                 std::string PipelineDesc,
+static void runNewPMCustomPasses(const Config &Conf, Module &Mod,
+                                 TargetMachine *TM, std::string PipelineDesc,
                                  std::string AAPipelineDesc,
                                  bool DisableVerify) {
   PassBuilder PB(TM);
@@ -241,6 +267,8 @@ static void runNewPMCustomPasses(Module &Mod, TargetMachine *TM,
       report_fatal_error("unable to parse AA pipeline description '" +
                          AAPipelineDesc + "': " + toString(std::move(Err)));
 
+  RegisterPassPlugins(Conf.PassPlugins, PB);
+
   LoopAnalysisManager LAM;
   FunctionAnalysisManager FAM;
   CGSCCAnalysisManager CGAM;
@@ -307,7 +335,7 @@ bool opt(const Config &Conf, TargetMachine *TM, unsigned Task, Module &Mod,
          const ModuleSummaryIndex *ImportSummary) {
   // FIXME: Plumb the combined index into the new pass manager.
   if (!Conf.OptPipeline.empty())
-    runNewPMCustomPasses(Mod, TM, Conf.OptPipeline, Conf.AAPipeline,
+    runNewPMCustomPasses(Conf, Mod, TM, Conf.OptPipeline, Conf.AAPipeline,
                          Conf.DisableVerify);
   else if (Conf.UseNewPM)
     runNewPMPasses(Conf, Mod, TM, Conf.OptLevel, IsThinLTO, ExportSummary,