1 files changed, 61 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/FuncletLayout.cpp b/llvm/lib/CodeGen/FuncletLayout.cpp
new file mode 100644
index 000000000000..75f6d0b8f0bf
--- /dev/null
+++ b/llvm/lib/CodeGen/FuncletLayout.cpp
@@ -0,0 +1,61 @@
+//===-- FuncletLayout.cpp - Contiguously lay out funclets -----------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements basic block placement transformations which result in
+// funclets being contiguous.
+//
+//===----------------------------------------------------------------------===//
+#include "llvm/CodeGen/Analysis.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/Passes.h"
+using namespace llvm;
+
+#define DEBUG_TYPE "funclet-layout"
+
+namespace {
+class FuncletLayout : public MachineFunctionPass {
+public:
+  static char ID; // Pass identification, replacement for typeid
+  FuncletLayout() : MachineFunctionPass(ID) {
+    initializeFuncletLayoutPass(*PassRegistry::getPassRegistry());
+  }
+
+  bool runOnMachineFunction(MachineFunction &F) override;
+  MachineFunctionProperties getRequiredProperties() const override {
+    return MachineFunctionProperties().set(
+        MachineFunctionProperties::Property::NoVRegs);
+  }
+};
+}
+
+char FuncletLayout::ID = 0;
+char &llvm::FuncletLayoutID = FuncletLayout::ID;
+INITIALIZE_PASS(FuncletLayout, DEBUG_TYPE,
+                "Contiguously Lay Out Funclets", false, false)
+
+bool FuncletLayout::runOnMachineFunction(MachineFunction &F) {
+  // Even though this gets information from getEHScopeMembership(), this pass is
+  // only necessary for funclet-based EH personalities, in which these EH scopes
+  // are outlined at the end.
+  DenseMap<const MachineBasicBlock *, int> FuncletMembership =
+      getEHScopeMembership(F);
+  if (FuncletMembership.empty())
+    return false;
+
+  F.sort([&](MachineBasicBlock &X, MachineBasicBlock &Y) {
+    auto FuncletX = FuncletMembership.find(&X);
+    auto FuncletY = FuncletMembership.find(&Y);
+    assert(FuncletX != FuncletMembership.end());
+    assert(FuncletY != FuncletMembership.end());
+    return FuncletX->second < FuncletY->second;
+  });
+
+  // Conservatively assume we changed something.
+  return true;
+}