From 83c7bddf7db2814422e8fd5bedddf15028fb003b Mon Sep 17 00:00:00 2001
From: Arthur Eubanks <aeubanks@google.com>
Date: Tue, 2 Mar 2021 14:49:46 -0800
Subject: [PATCH] [opt] Error if -debug-pass is specified alongside the new PM

Reviewed By: ychen

Differential Revision: https://reviews.llvm.org/D97810
---
 include/llvm/IR/LegacyPassManager.h | 4 ++++
 lib/IR/LegacyPassManager.cpp        | 2 ++
 test/Other/debug-pass-npm.ll        | 4 ++++
 tools/opt/opt.cpp                   | 6 ++++++
 4 files changed, 16 insertions(+)
 create mode 100644 test/Other/debug-pass-npm.ll

diff --git a/include/llvm/IR/LegacyPassManager.h b/include/llvm/IR/LegacyPassManager.h
index 2b87143276b..2459f0a5450 100644
--- a/include/llvm/IR/LegacyPassManager.h
+++ b/include/llvm/IR/LegacyPassManager.h
@@ -26,6 +26,10 @@ class Module;
 
 namespace legacy {
 
+// Whether or not -debug-pass has been specified. For use to check if it's
+// specified alongside the new PM.
+bool debugPassSpecified();
+
 class PassManagerImpl;
 class FunctionPassManagerImpl;
 
diff --git a/lib/IR/LegacyPassManager.cpp b/lib/IR/LegacyPassManager.cpp
index 94be208617c..32840fdeddf 100644
--- a/lib/IR/LegacyPassManager.cpp
+++ b/lib/IR/LegacyPassManager.cpp
@@ -242,6 +242,8 @@ void PassManagerPrettyStackEntry::print(raw_ostream &OS) const {
 
 namespace llvm {
 namespace legacy {
+bool debugPassSpecified() { return PassDebugging != Disabled; }
+
 //===----------------------------------------------------------------------===//
 // FunctionPassManagerImpl
 //
diff --git a/test/Other/debug-pass-npm.ll b/test/Other/debug-pass-npm.ll
new file mode 100644
index 00000000000..55c9baa6c57
--- /dev/null
+++ b/test/Other/debug-pass-npm.ll
@@ -0,0 +1,4 @@
+; RUN: opt -enable-new-pm=0 -O1 %s -debug-pass=Structure
+; RUN: not opt -enable-new-pm=1 -O1 %s -debug-pass=Structure 2>&1 | FileCheck %s
+
+; CHECK: does not work
diff --git a/tools/opt/opt.cpp b/tools/opt/opt.cpp
index 48b0e397c98..f690d5f1a78 100644
--- a/tools/opt/opt.cpp
+++ b/tools/opt/opt.cpp
@@ -775,6 +775,12 @@ int main(int argc, char **argv) {
                 "full list of passes, see the '--print-passes' flag.\n";
       return 1;
     }
+    if (legacy::debugPassSpecified()) {
+      errs()
+          << "-debug-pass does not work with the new PM, either use "
+             "-debug-pass-manager, or use the legacy PM (-enable-new-pm=0)\n";
+      return 1;
+    }
     if (PassPipeline.getNumOccurrences() > 0 && PassList.size() > 0) {
       errs()
           << "Cannot specify passes via both -foo-pass and --passes=foo-pass\n";