From 9d5e6474281cd4d774ede800eb339e1dc610e471 Mon Sep 17 00:00:00 2001
From: Lang Hames <lhames@gmail.com>
Date: Fri, 12 Nov 2021 08:46:03 -0800
Subject: [PATCH] [JITLink] Fix think-o in handwritten CWrapperFunctionResult
 -> Error converter.

We need to skip the length field when generating error strings.

No test case: This hand-hacked deserializer should be removed in the near future
once JITLink can use generic ORC APIs (including SPS and WrapperFunction).
---
 llvm/lib/ExecutionEngine/JITLink/JITLinkMemoryManager.cpp | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/ExecutionEngine/JITLink/JITLinkMemoryManager.cpp b/llvm/lib/ExecutionEngine/JITLink/JITLinkMemoryManager.cpp
index 0e5ed8e3d1ce..4fb349255f75 100644
--- a/llvm/lib/ExecutionEngine/JITLink/JITLinkMemoryManager.cpp
+++ b/llvm/lib/ExecutionEngine/JITLink/JITLinkMemoryManager.cpp
@@ -40,8 +40,9 @@ Error toError(CWrapperFunctionResult R) {
     char *Content = Large ? R.Data.ValuePtr : R.Data.Value;
     if (Content[0]) {
       HasError = true;
-      ErrMsg.resize(R.Size - 1);
-      memcpy(&ErrMsg[0], Content + 1, R.Size - 1);
+      constexpr unsigned StrStart = 1 + sizeof(uint64_t);
+      ErrMsg.resize(R.Size - StrStart);
+      memcpy(&ErrMsg[0], Content + StrStart, R.Size - StrStart);
     }
     if (Large)
       free(R.Data.ValuePtr);