Index: include/clang/Basic/CodeGenOptions.h
===================================================================
--- include/clang/Basic/CodeGenOptions.h
+++ include/clang/Basic/CodeGenOptions.h
@@ -287,6 +287,9 @@
 
   std::vector<std::string> DefaultFunctionAttrs;
 
+  /// List of dynamic shared object files to be loaded as pass plugins.
+  std::vector<std::string> PassPlugins;
+
 public:
   // Define accessors/mutators for code generation options of enumeration type.
 #define CODEGENOPT(Name, Bits, Default)
Index: include/clang/Driver/Options.td
===================================================================
--- include/clang/Driver/Options.td
+++ include/clang/Driver/Options.td
@@ -1612,6 +1612,9 @@
 def fno_rwpi : Flag<["-"], "fno-rwpi">, Group<f_Group>;
 def fplugin_EQ : Joined<["-"], "fplugin=">, Group<f_Group>, Flags<[DriverOption]>, MetaVarName<"<dsopath>">,
   HelpText<"Load the named plugin (dynamic shared object)">;
+def fpass_plugin_EQ : Joined<["-"], "fpass-plugin=">,
+  Group<f_Group>, Flags<[CC1Option]>, MetaVarName<"<dsopath>">,
+  HelpText<"Load pass plugin from a dynamic shared object file (only with new pass manager).">;
 def fpreserve_as_comments : Flag<["-"], "fpreserve-as-comments">, Group<f_Group>;
 def fno_preserve_as_comments : Flag<["-"], "fno-preserve-as-comments">, Group<f_Group>, Flags<[CC1Option]>,
   HelpText<"Do not preserve comments in inline assembly">;
Index: lib/CodeGen/BackendUtil.cpp
===================================================================
--- lib/CodeGen/BackendUtil.cpp
+++ lib/CodeGen/BackendUtil.cpp
@@ -36,6 +36,7 @@
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/MC/SubtargetFeature.h"
 #include "llvm/Passes/PassBuilder.h"
+#include "llvm/Passes/PassPlugin.h"
 #include "llvm/Support/BuryPointer.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/MemoryBuffer.h"
@@ -961,6 +962,17 @@
 
   PassBuilder PB(TM.get(), PGOOpt);
 
+  // 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());
+    }
+  }
+
   LoopAnalysisManager LAM(CodeGenOpts.DebugPassManager);
   FunctionAnalysisManager FAM(CodeGenOpts.DebugPassManager);
   CGSCCAnalysisManager CGAM(CodeGenOpts.DebugPassManager);
Index: lib/Driver/ToolChains/Clang.cpp
===================================================================
--- lib/Driver/ToolChains/Clang.cpp
+++ lib/Driver/ToolChains/Clang.cpp
@@ -5077,6 +5077,13 @@
     A->claim();
   }
 
+  // Forward -fpass-plugin=name.so to -cc1.
+  for (const Arg *A : Args.filtered(options::OPT_fpass_plugin_EQ)) {
+    CmdArgs.push_back(
+        Args.MakeArgString(Twine("-fpass-plugin=") + A->getValue()));
+    A->claim();
+  }
+
   // Setup statistics file output.
   SmallString<128> StatsFile = getStatsFileName(Args, Output, Input, D);
   if (!StatsFile.empty())
Index: lib/Frontend/CompilerInvocation.cpp
===================================================================
--- lib/Frontend/CompilerInvocation.cpp
+++ lib/Frontend/CompilerInvocation.cpp
@@ -1322,6 +1322,8 @@
 
   Opts.DefaultFunctionAttrs = Args.getAllArgValues(OPT_default_function_attr);
 
+  Opts.PassPlugins = Args.getAllArgValues(OPT_fpass_plugin_EQ);
+
   return Success;
 }