[llvm] 46f5852 - [llvm] Fixed Demangle OutputBuffer (#138564)

[via llvm-commits]

Author: Dmitry Vasilyev
Date: 2025-05-06T00:12:59+04:00
New Revision: 46f5852ad9a8025bc30d10d4e88af99fae2edbc8

URL: https://github.com/llvm/llvm-project/commit/46f5852ad9a8025bc30d10d4e88af99fae2edbc8
DIFF: https://github.com/llvm/llvm-project/commit/46f5852ad9a8025bc30d10d4e88af99fae2edbc8.diff

LOG: [llvm] Fixed Demangle OutputBuffer (#138564)

The [llvm-clang-x86_64-expensive-checks-win](https://lab.llvm.org/buildbot/#/builders/14/builds/3075)
buildbot has been broken by #133249.
DemangleTests causes the exception 0x80000003 inside CRT in case of the debug build on Windows.

Added: 
    

Modified: 
    llvm/include/llvm/Demangle/Utility.h

Removed: 
    


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diff  --git a/llvm/include/llvm/Demangle/Utility.h b/llvm/include/llvm/Demangle/Utility.h
index d59d74511dd4f..002a1f55467d6 100644
--- a/llvm/include/llvm/Demangle/Utility.h
+++ b/llvm/include/llvm/Demangle/Utility.h
@@ -136,6 +136,8 @@ class OutputBuffer {
 
   OutputBuffer &prepend(std::string_view R) {
     size_t Size = R.size();
+    if (!Size)
+      return *this;
 
     grow(Size);
     std::memmove(Buffer + Size, Buffer, CurrentPosition);