Revert "[flang] Add -fpass-plugin option to Flang frontend"

This reverts commit 43fe6f7cc35ded691bbc2fa844086d321e705d46.

Reverting this as CI breaks.

To reproduce, run check-flang, and it will fail with an error saying
.../lib/Bye.so not found in pass-plugin.f90

10 files changed, 2 insertions, 75 deletions

diff --git a/flang/docs/FlangDriver.md b/flang/docs/FlangDriver.md
index b44f44e..af1fddc 100644
--- a/flang/docs/FlangDriver.md
+++ b/flang/docs/FlangDriver.md
@@ -507,28 +507,3 @@ Lastly, if `ParseTree` modifications are performed, then it might be necessary
 to re-analyze expressions and modify scope or symbols. You can check
 [Semantics.md](Semantics.md) for more details on how `ParseTree` is edited
 e.g. during the semantic checks.
-
-# LLVM Pass Plugins
-
-Pass plugins are dynamic shared objects that consist of one or more LLVM IR
-passes. The `-fpass-plugin` option enables these passes to be passed to the 
-middle-end where they are added to the optimization pass pipeline and run after
-lowering to LLVM IR.The exact position of the pass in the pipeline will depend 
-on how it has been registered with the `llvm::PassBuilder`. See the 
-documentation for 
-[`llvm::PassBuilder`](https://llvm.org/doxygen/classllvm_1_1PassBuilder.html)
-for details. 
-
-The framework to enable pass plugins in `flang-new` uses the exact same 
-machinery as that used by `clang` and thus has the same capabilities and
-limitations. 
-
-In order to use a pass plugin, the pass(es) must be compiled into a dynamic 
-shared object which is then loaded using the `-fpass-plugin` option. 
-
-```
-flang-new -fpass-plugin=/path/to/plugin.so <file.f90>
-```
-
-This option is available in both the compiler driver and the frontend driver. 
-Note that LLVM plugins are not officially supported on Windows.
diff --git a/flang/docs/ReleaseNotes.md b/flang/docs/ReleaseNotes.md
index 0cc85db..fd1db3b0 100644
--- a/flang/docs/ReleaseNotes.md
+++ b/flang/docs/ReleaseNotes.md
@@ -24,10 +24,6 @@ page](https://llvm.org/releases/).
 
 ## Major New Features
 
-* Flang now supports loading LLVM pass plugins with the `-fpass-plugin` option
-  which is also available in clang. The option mimics the behavior of the
-  corresponding option in clang and has the same capabilities and limitations.
-
 ## Bug Fixes
 
 ## Non-comprehensive list of changes in this release
diff --git a/flang/include/flang/Frontend/CodeGenOptions.h b/flang/include/flang/Frontend/CodeGenOptions.h
index 7bb10d4..025f67c 100644
--- a/flang/include/flang/Frontend/CodeGenOptions.h
+++ b/flang/include/flang/Frontend/CodeGenOptions.h
@@ -46,9 +46,6 @@ protected:
 class CodeGenOptions : public CodeGenOptionsBase {
 
 public:
-  /// The paths to the pass plugins that were registered using -fpass-plugin.
-  std::vector<std::string> LLVMPassPlugins;
-
   // Define accessors/mutators for code generation options of enumeration type.
 #define CODEGENOPT(Name, Bits, Default)
 #define ENUM_CODEGENOPT(Name, Type, Bits, Default)                             \
diff --git a/flang/lib/Frontend/CompilerInvocation.cpp b/flang/lib/Frontend/CompilerInvocation.cpp
index b00a2a3d..0ad63b0 100644
--- a/flang/lib/Frontend/CompilerInvocation.cpp
+++ b/flang/lib/Frontend/CompilerInvocation.cpp
@@ -125,9 +125,6 @@ static void parseCodeGenArgs(Fortran::frontend::CodeGenOptions &opts,
                    clang::driver::options::OPT_fno_debug_pass_manager, false))
     opts.DebugPassManager = 1;
 
-  for (auto *a : args.filtered(clang::driver::options::OPT_fpass_plugin_EQ))
-    opts.LLVMPassPlugins.push_back(a->getValue());
-
   // -mrelocation-model option.
   if (const llvm::opt::Arg *A =
           args.getLastArg(clang::driver::options::OPT_mrelocation_model)) {
diff --git a/flang/lib/Frontend/FrontendActions.cpp b/flang/lib/Frontend/FrontendActions.cpp
index d1c1ec1..be91a79 100644
--- a/flang/lib/Frontend/FrontendActions.cpp
+++ b/flang/lib/Frontend/FrontendActions.cpp
@@ -46,7 +46,6 @@
 #include "llvm/IRReader/IRReader.h"
 #include "llvm/MC/TargetRegistry.h"
 #include "llvm/Passes/PassBuilder.h"
-#include "llvm/Passes/PassPlugin.h"
 #include "llvm/Passes/StandardInstrumentations.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/SourceMgr.h"
@@ -661,7 +660,6 @@ static void generateMachineCodeOrAssemblyImpl(clang::DiagnosticsEngine &diags,
 
 void CodeGenAction::runOptimizationPipeline(llvm::raw_pwrite_stream &os) {
   auto opts = getInstance().getInvocation().getCodeGenOpts();
-  auto &diags = getInstance().getDiagnostics();
   llvm::OptimizationLevel level = mapToLevel(opts);
 
   // Create the analysis managers.
@@ -678,17 +676,6 @@ void CodeGenAction::runOptimizationPipeline(llvm::raw_pwrite_stream &os) {
   si.registerCallbacks(pic, &fam);
   llvm::PassBuilder pb(tm.get(), pto, pgoOpt, &pic);
 
-  // Attempt to load pass plugins and register their callbacks with PB.
-  for (auto &pluginFile : opts.LLVMPassPlugins) {
-    auto passPlugin = llvm::PassPlugin::Load(pluginFile);
-    if (passPlugin) {
-      passPlugin->registerPassBuilderCallbacks(pb);
-    } else {
-      diags.Report(clang::diag::err_fe_unable_to_load_plugin)
-          << pluginFile << passPlugin.takeError();
-    }
-  }
-
   // Register all the basic analyses with the managers.
   pb.registerModuleAnalyses(mam);
   pb.registerCGSCCAnalyses(cgam);
diff --git a/flang/test/Driver/driver-help-hidden.f90 b/flang/test/Driver/driver-help-hidden.f90
index 3ee13fc..8261620 100644
--- a/flang/test/Driver/driver-help-hidden.f90
+++ b/flang/test/Driver/driver-help-hidden.f90
@@ -44,7 +44,6 @@
 ! CHECK-NEXT: -fno-integrated-as     Disable the integrated assembler
 ! CHECK-NEXT: -fopenacc              Enable OpenACC
 ! CHECK-NEXT: -fopenmp               Parse OpenMP pragmas and generate parallel code.
-! CHECK-NEXT: -fpass-plugin=<dsopath> Load pass plugin from a dynamic shared object file (only with new pass manager).
 ! CHECK-NEXT: -fsyntax-only          Run the preprocessor, parser and semantic analysis stages
 ! CHECK-NEXT: -fxor-operator         Enable .XOR. as a synonym of .NEQV.
 ! CHECK-NEXT: -help     Display available options
@@ -72,3 +71,4 @@
 
 ! Frontend driver -help-hidden is not supported
 ! ERROR-FLANG-FC1: error: unknown argument: '{{.*}}'
+
diff --git a/flang/test/Driver/driver-help.f90 b/flang/test/Driver/driver-help.f90
index e3a3807..99201e0 100644
--- a/flang/test/Driver/driver-help.f90
+++ b/flang/test/Driver/driver-help.f90
@@ -42,7 +42,6 @@
 ! HELP-NEXT: -fno-integrated-as      Disable the integrated assembler
 ! HELP-NEXT: -fopenacc              Enable OpenACC
 ! HELP-NEXT: -fopenmp               Parse OpenMP pragmas and generate parallel code.
-! HELP-NEXT: -fpass-plugin=<dsopath> Load pass plugin from a dynamic shared object file (only with new pass manager).
 ! HELP-NEXT: -fsyntax-only          Run the preprocessor, parser and semantic analysis stages
 ! HELP-NEXT: -fxor-operator         Enable .XOR. as a synonym of .NEQV.
 ! HELP-NEXT: -help                  Display available options
@@ -121,7 +120,6 @@
 ! HELP-FC1-NEXT: -fno-reformat          Dump the cooked character stream in -E mode
 ! HELP-FC1-NEXT: -fopenacc              Enable OpenACC
 ! HELP-FC1-NEXT: -fopenmp               Parse OpenMP pragmas and generate parallel code.
-! HELP-FC1-NEXT: -fpass-plugin=<dsopath> Load pass plugin from a dynamic shared object file (only with new pass manager).
 ! HELP-FC1-NEXT: -fsyntax-only          Run the preprocessor, parser and semantic analysis stages
 ! HELP-FC1-NEXT: -fxor-operator         Enable .XOR. as a synonym of .NEQV.
 ! HELP-FC1-NEXT: -help                  Display available options
diff --git a/flang/test/Driver/frontend-forwarding.f90 b/flang/test/Driver/frontend-forwarding.f90
index bdf0c31..14d7985 100644
--- a/flang/test/Driver/frontend-forwarding.f90
+++ b/flang/test/Driver/frontend-forwarding.f90
@@ -7,7 +7,6 @@
 ! RUN:     -fdefault-integer-8 \
 ! RUN:     -fdefault-real-8 \
 ! RUN:     -flarge-sizes \
-! RUN:     -fpass-plugin=Bye%pluginext \
 ! RUN:     -mllvm -print-before-all\
 ! RUN:     -P \
 ! RUN:   | FileCheck %s
@@ -18,5 +17,4 @@
 ! CHECK: "-fdefault-integer-8"
 ! CHECK: "-fdefault-real-8"
 ! CHECK: "-flarge-sizes"
-! CHECK: "-fpass-plugin=Bye
-! CHECK: "-mllvm" "-print-before-all"
+! CHECK:  "-mllvm" "-print-before-all"
diff --git a/flang/test/Driver/pass-plugin-not-found.f90 b/flang/test/Driver/pass-plugin-not-found.f90
deleted file mode 100644
index a93567a..0000000
--- a/flang/test/Driver/pass-plugin-not-found.f90
+++ /dev/null
@@ -1,8 +0,0 @@
-! Check the correct error diagnostic is reported when a pass plugin shared object isn't found
-
-! REQUIRES: plugins, shell
-
-! RUN: not %flang -fpass-plugin=X.Y %s 2>&1 | FileCheck %s --check-prefix=ERROR
-! RUN: not %flang_fc1 -emit-llvm -o /dev/null -fpass-plugin=X.Y %s 2>&1 | FileCheck %s --check-prefix=ERROR
-
-! ERROR: error: unable to load plugin 'X.Y': 'Could not load library 'X.Y': X.Y: cannot open shared object file: No such file or directory'
diff --git a/flang/test/Driver/pass-plugin.f90 b/flang/test/Driver/pass-plugin.f90
deleted file mode 100644
index 546bd92..0000000
--- a/flang/test/Driver/pass-plugin.f90
+++ /dev/null
@@ -1,13 +0,0 @@
-! Verify that the plugin passed to -fpass-plugin is loaded and run
-
-! UNSUPPORTED: system-windows
-
-! REQUIRES: plugins, shell
-
-! RUN: %flang -S %s -fpass-plugin=%llvmshlibdir/Bye%pluginext -Xflang -fdebug-pass-manager -o /dev/null 2>&1 | FileCheck %s
-! RUN: %flang_fc1 -S %s -fpass-plugin=%llvmshlibdir/Bye%pluginext -fdebug-pass-manager -o /dev/null 2>&1 | FileCheck %s
-
-! CHECK: Running pass: {{.*}}Bye on empty_
-
-subroutine empty
-end subroutine empty