From a8cde5881bf55fe986210c50dae49655e53c6eba Mon Sep 17 00:00:00 2001
From: Daniel Sanders <daniel_l_sanders@apple.com>
Date: Fri, 17 Apr 2020 10:24:35 -0700
Subject: [PATCH] Don't accidentally create MachineFunctions in
 mir-debugify/mir-strip-debugify

We should only modify existing ones. Previously, we were creating
MachineFunctions for externally-available functions. AFAICT this was benign
in tree but ultimately led to asan bugs in our out of tree target.
---
 lib/CodeGen/MachineDebugify.cpp   | 5 ++++-
 lib/CodeGen/MachineStripDebug.cpp | 5 ++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/lib/CodeGen/MachineDebugify.cpp b/lib/CodeGen/MachineDebugify.cpp
index bee9b634675..bc607cabcc6 100644
--- a/lib/CodeGen/MachineDebugify.cpp
+++ b/lib/CodeGen/MachineDebugify.cpp
@@ -27,7 +27,10 @@ using namespace llvm;
 namespace {
 bool applyDebugifyMetadataToMachineFunction(MachineModuleInfo &MMI,
                                             DIBuilder &DIB, Function &F) {
-  MachineFunction &MF = MMI.getOrCreateMachineFunction(F);
+  MachineFunction *MaybeMF = MMI.getMachineFunction(F);
+  if (!MaybeMF)
+    return false;
+  MachineFunction &MF = *MaybeMF;
 
   DISubprogram *SP = F.getSubprogram();
   assert(SP && "IR Debugify just created it?");
diff --git a/lib/CodeGen/MachineStripDebug.cpp b/lib/CodeGen/MachineStripDebug.cpp
index 48b50ceb092..a1cb12f9127 100644
--- a/lib/CodeGen/MachineStripDebug.cpp
+++ b/lib/CodeGen/MachineStripDebug.cpp
@@ -45,7 +45,10 @@ struct StripDebugMachineModule : public ModulePass {
 
     bool Changed = false;
     for (Function &F : M.functions()) {
-      MachineFunction &MF = MMI.getOrCreateMachineFunction(F);
+      MachineFunction *MaybeMF = MMI.getMachineFunction(F);
+      if (!MaybeMF)
+        continue;
+      MachineFunction &MF = *MaybeMF;
       for (MachineBasicBlock &MBB : MF) {
         for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end();
              I != E;) {