From 72ce310bf0deceea6929eebbfc0d65e799d86ad9 Mon Sep 17 00:00:00 2001
From: Amara Emerson <amara@apple.com>
Date: Thu, 7 Oct 2021 23:26:35 -0700
Subject: [PATCH] [GlobalISel][IRTranslator] Fix a use-after-free bug when
 translating trap-func-name traps.

This was using MachineFunction::createExternalSymbolName() before, which seems
reasonable, but in fact this is freed before the asm emitter which tries to access
the function name string. Switching it to use the string returned by the attribute
seems to fix the problem.
---
 llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
index 711006df0245..40d58d555d3d 100644
--- a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
@@ -2246,8 +2246,7 @@ bool IRTranslator::translateKnownIntrinsic(const CallInst &CI, Intrinsic::ID ID,
       Info.OrigArgs.push_back({getOrCreateVRegs(*CI.getArgOperand(0)),
                                CI.getArgOperand(0)->getType(), 0});
     }
-    Info.Callee =
-        MachineOperand::CreateES(MF->createExternalSymbolName(TrapFuncName));
+    Info.Callee = MachineOperand::CreateES(TrapFuncName.data());
     Info.CB = &CI;
     Info.OrigRet = {Register(), Type::getVoidTy(CI.getContext()), 0};
     return CLI->lowerCall(MIRBuilder, Info);