diff --git a/llvm/include/llvm/CodeGen/Passes.h b/llvm/include/llvm/CodeGen/Passes.h
--- a/llvm/include/llvm/CodeGen/Passes.h
+++ b/llvm/include/llvm/CodeGen/Passes.h
@@ -473,6 +473,8 @@
   /// Create IR Type Promotion pass. \see TypePromotion.cpp
   FunctionPass *createTypePromotionPass();
 
+  /// Creates MIR Debugify pass. \see MachineDebugify.cpp
+  ModulePass *createDebugifyMachineModulePass();
 } // End llvm namespace
 
 #endif
diff --git a/llvm/include/llvm/InitializePasses.h b/llvm/include/llvm/InitializePasses.h
--- a/llvm/include/llvm/InitializePasses.h
+++ b/llvm/include/llvm/InitializePasses.h
@@ -121,6 +121,7 @@
 void initializeDataFlowSanitizerPass(PassRegistry&);
 void initializeDeadInstEliminationPass(PassRegistry&);
 void initializeDeadMachineInstructionElimPass(PassRegistry&);
+void initializeDebugifyMachineModulePass(PassRegistry &);
 void initializeDelinearizationPass(PassRegistry&);
 void initializeDemandedBitsWrapperPassPass(PassRegistry&);
 void initializeDependenceAnalysisPass(PassRegistry&);
diff --git a/llvm/include/llvm/Transforms/Utils/Debugify.h b/llvm/include/llvm/Transforms/Utils/Debugify.h
--- a/llvm/include/llvm/Transforms/Utils/Debugify.h
+++ b/llvm/include/llvm/Transforms/Utils/Debugify.h
@@ -17,6 +17,22 @@
 #include "llvm/ADT/MapVector.h"
 #include "llvm/IR/PassManager.h"
 
+namespace llvm {
+class DIBuilder;
+
+/// Add synthesized debug information to a module.
+///
+/// \param M The module to add debug information to.
+/// \param Functions A range of functions to add debug information to.
+/// \param Banner A prefix string to add to debug/error messages.
+/// \param ApplyToMF A call back that will add debug information to the
+///                  MachineFunction for a Function. If nullptr, then the
+///                  MachineFunction (if any) will not be modified.
+bool applyDebugifyMetadata(
+    Module &M, iterator_range<Module::iterator> Functions, StringRef Banner,
+    std::function<bool(DIBuilder &, Function &)> ApplyToMF);
+} // namespace llvm
+
 llvm::ModulePass *createDebugifyModulePass();
 llvm::FunctionPass *createDebugifyFunctionPass();
 
diff --git a/llvm/lib/CodeGen/CMakeLists.txt b/llvm/lib/CodeGen/CMakeLists.txt
--- a/llvm/lib/CodeGen/CMakeLists.txt
+++ b/llvm/lib/CodeGen/CMakeLists.txt
@@ -73,6 +73,7 @@
   MachineCombiner.cpp
   MachineCopyPropagation.cpp
   MachineCSE.cpp
+  MachineDebugify.cpp
   MachineDominanceFrontier.cpp
   MachineDominators.cpp
   MachineFrameInfo.cpp
diff --git a/llvm/lib/CodeGen/CodeGen.cpp b/llvm/lib/CodeGen/CodeGen.cpp
--- a/llvm/lib/CodeGen/CodeGen.cpp
+++ b/llvm/lib/CodeGen/CodeGen.cpp
@@ -27,6 +27,7 @@
   initializeCFIInstrInserterPass(Registry);
   initializeCodeGenPreparePass(Registry);
   initializeDeadMachineInstructionElimPass(Registry);
+  initializeDebugifyMachineModulePass(Registry);
   initializeDetectDeadLanesPass(Registry);
   initializeDwarfEHPreparePass(Registry);
   initializeEarlyIfConverterPass(Registry);
diff --git a/llvm/lib/CodeGen/MachineDebugify.cpp b/llvm/lib/CodeGen/MachineDebugify.cpp
new file mode 100644
--- /dev/null
+++ b/llvm/lib/CodeGen/MachineDebugify.cpp
@@ -0,0 +1,84 @@
+//===- MachineDebugify.cpp - Attach synthetic debug info to everything ----===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file This pass attaches synthetic debug info to everything. It can be used
+/// to create targeted tests for debug info preservation.
+///
+/// This isn't intended to have feature parity with Debugify.
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/IR/DIBuilder.h"
+#include "llvm/IR/DebugInfo.h"
+#include "llvm/InitializePasses.h"
+#include "llvm/Transforms/Utils/Debugify.h"
+
+#define DEBUG_TYPE "mir-debugify"
+
+using namespace llvm;
+
+namespace {
+bool applyDebugifyMetadataToMachineFunction(MachineModuleInfo &MMI,
+                                            DIBuilder &DIB, Function &F) {
+  MachineFunction &MF = MMI.getOrCreateMachineFunction(F);
+
+  DISubprogram *SP = F.getSubprogram();
+  assert(SP && "IR Debugify just created it?");
+
+  LLVMContext &Ctx = F.getParent()->getContext();
+  unsigned NextLine = SP->getLine();
+
+  for (MachineBasicBlock &MBB : MF) {
+    for (MachineInstr &MI : MBB) {
+      // This will likely emit line numbers beyond the end of the imagined
+      // source function and into subsequent ones. We don't do anything about
+      // that as it doesn't really matter to the compiler where the line is in
+      // the imaginary source code.
+      MI.setDebugLoc(DILocation::get(Ctx, NextLine++, 1, SP));
+    }
+  }
+
+  return true;
+}
+
+/// ModulePass for attaching synthetic debug info to everything, used with the
+/// legacy module pass manager.
+struct DebugifyMachineModule : public ModulePass {
+  bool runOnModule(Module &M) override {
+    MachineModuleInfo &MMI =
+        getAnalysis<MachineModuleInfoWrapperPass>().getMMI();
+    return applyDebugifyMetadata(
+        M, M.functions(),
+        "ModuleDebugify: ", [&](DIBuilder &DIB, Function &F) -> bool {
+          return applyDebugifyMetadataToMachineFunction(MMI, DIB, F);
+        });
+  }
+
+  DebugifyMachineModule() : ModulePass(ID) {}
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
+    AU.addRequired<MachineModuleInfoWrapperPass>();
+    AU.addPreserved<MachineModuleInfoWrapperPass>();
+  }
+
+  static char ID; // Pass identification.
+};
+char DebugifyMachineModule::ID = 0;
+
+} // end anonymous namespace
+
+INITIALIZE_PASS_BEGIN(DebugifyMachineModule, DEBUG_TYPE,
+                      "Machine Debugify Module", false, false)
+INITIALIZE_PASS_END(DebugifyMachineModule, DEBUG_TYPE,
+                    "Machine Debugify Module", false, false)
+
+ModulePass *createDebugifyMachineModulePass() {
+  return new DebugifyMachineModule();
+}
diff --git a/llvm/lib/Transforms/Utils/Debugify.cpp b/llvm/lib/Transforms/Utils/Debugify.cpp
--- a/llvm/lib/Transforms/Utils/Debugify.cpp
+++ b/llvm/lib/Transforms/Utils/Debugify.cpp
@@ -62,10 +62,11 @@
     return I;
   return BB.getTerminator();
 }
+} // end anonymous namespace
 
-bool applyDebugifyMetadata(Module &M,
-                           iterator_range<Module::iterator> Functions,
-                           StringRef Banner) {
+bool llvm::applyDebugifyMetadata(
+    Module &M, iterator_range<Module::iterator> Functions, StringRef Banner,
+    std::function<bool(DIBuilder &DIB, Function &F)> ApplyToMF) {
   // Skip modules with debug info.
   if (M.getNamedMetadata("llvm.dbg.cu")) {
     dbg() << Banner << "Skipping module with debug info\n";
@@ -149,6 +150,8 @@
                                     InsertBefore);
       }
     }
+    if (ApplyToMF)
+      ApplyToMF(DIB, F);
     DIB.finalizeSubprogram(SP);
   }
   DIB.finalize();
@@ -173,6 +176,7 @@
   return true;
 }
 
+namespace {
 /// Return true if a mis-sized diagnostic is issued for \p DVI.
 bool diagnoseMisSizedDbgValue(Module &M, DbgValueInst *DVI) {
   // The size of a dbg.value's value operand should match the size of the
@@ -315,7 +319,8 @@
 /// legacy module pass manager.
 struct DebugifyModulePass : public ModulePass {
   bool runOnModule(Module &M) override {
-    return applyDebugifyMetadata(M, M.functions(), "ModuleDebugify: ");
+    return applyDebugifyMetadata(M, M.functions(),
+                                 "ModuleDebugify: ", /*ApplyToMF*/ nullptr);
   }
 
   DebugifyModulePass() : ModulePass(ID) {}
@@ -334,7 +339,7 @@
     Module &M = *F.getParent();
     auto FuncIt = F.getIterator();
     return applyDebugifyMetadata(M, make_range(FuncIt, std::next(FuncIt)),
-                                 "FunctionDebugify: ");
+                                 "FunctionDebugify: ", /*ApplyToMF*/ nullptr);
   }
 
   DebugifyFunctionPass() : FunctionPass(ID) {}
@@ -409,7 +414,8 @@
 }
 
 PreservedAnalyses NewPMDebugifyPass::run(Module &M, ModuleAnalysisManager &) {
-  applyDebugifyMetadata(M, M.functions(), "ModuleDebugify: ");
+  applyDebugifyMetadata(M, M.functions(),
+                        "ModuleDebugify: ", /*ApplyToMF*/ nullptr);
   return PreservedAnalyses::all();
 }
 
diff --git a/llvm/test/CodeGen/Generic/MIRDebugify/locations.mir b/llvm/test/CodeGen/Generic/MIRDebugify/locations.mir
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/Generic/MIRDebugify/locations.mir
@@ -0,0 +1,37 @@
+# RUN: llc -run-pass=mir-debugify -o - %s | FileCheck --check-prefixes=ALL,VALUE %s
+# RUN: llc -run-pass=mir-debugify -debugify-level=locations -o - %s | FileCheck --check-prefixes=ALL --implicit-check-not=dbg.value %s
+--- |
+  ; ModuleID = 'loc-only.ll'
+  source_filename = "loc-only.ll"
+  
+  ; ALL-LABEL: @test
+  define i32 @test(i32 %a, i32 %b) {
+    %add = add i32 %a, 2
+  ; ALL-NEXT:  %add = add i32 %a, 2, !dbg [[L1:![0-9]+]]
+  ; VALUE-NEXT: call void @llvm.dbg.value(metadata i32 %add, metadata [[add:![0-9]+]], metadata !DIExpression()), !dbg [[L1]]
+    %sub = sub i32 %add, %b
+  ; ALL-NEXT: %sub = sub i32 %add, %b, !dbg [[L2:![0-9]+]]
+  ; VALUE-NEXT: call void @llvm.dbg.value(metadata i32 %sub, metadata [[sub:![0-9]+]], metadata !DIExpression()), !dbg [[L2]]
+  ; ALL-NEXT: ret i32 %sub, !dbg [[L3:![0-9]+]]
+    ret i32 %sub
+  }
+
+...
+---
+name:            test
+body:             |
+  bb.1 (%ir-block.0):
+    %0:_(s32) = IMPLICIT_DEF
+    %1:_(s32) = IMPLICIT_DEF
+    %2:_(s32) = G_CONSTANT i32 2
+    %3:_(s32) = G_ADD %0, %2
+    %4:_(s32) = G_SUB %3, %1
+    ; There's no attempt to have the locations make sense as it's an imaginary
+    ; source file anyway. These first three coincide with IR-level information
+    ; and therefore use metadata references.
+    ; ALL: %0:_(s32) = IMPLICIT_DEF debug-location [[L1]]
+    ; ALL: %1:_(s32) = IMPLICIT_DEF debug-location [[L2]]
+    ; ALL: %2:_(s32) = G_CONSTANT i32 2, debug-location [[L3]]
+    ; ALL: %3:_(s32) = G_ADD %0, %2, debug-location !DILocation(line: 4, column: 1, scope: !6)
+    ; ALL: %4:_(s32) = G_SUB %3, %1, debug-location !DILocation(line: 5, column: 1, scope: !6)
+...