From 044eb2f6afba375a914ac9d8024f8f5142bb912e Mon Sep 17 00:00:00 2001
From: Dimitry Andric <dim@FreeBSD.org>
Date: Mon, 18 Dec 2017 20:10:56 +0000
Subject: Vendor import of llvm trunk r321017:
 https://llvm.org/svn/llvm-project/llvm/trunk@321017

---
 include/llvm/DebugInfo/CodeView/SymbolSerializer.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

(limited to 'include/llvm/DebugInfo/CodeView/SymbolSerializer.h')

diff --git a/include/llvm/DebugInfo/CodeView/SymbolSerializer.h b/include/llvm/DebugInfo/CodeView/SymbolSerializer.h
index b63ced5217b4..f4d8ab0c3c2e 100644
--- a/include/llvm/DebugInfo/CodeView/SymbolSerializer.h
+++ b/include/llvm/DebugInfo/CodeView/SymbolSerializer.h
@@ -28,7 +28,10 @@ namespace codeview {
 
 class SymbolSerializer : public SymbolVisitorCallbacks {
   BumpPtrAllocator &Storage;
-  std::vector<uint8_t> RecordBuffer;
+  // Since this is a fixed size buffer, use a stack allocated buffer.  This
+  // yields measurable performance increase over the repeated heap allocations
+  // when serializing many independent records via writeOneSymbol.
+  std::array<uint8_t, MaxRecordLength> RecordBuffer;
   MutableBinaryByteStream Stream;
   BinaryStreamWriter Writer;
   SymbolRecordMapping Mapping;
-- 
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