[Support] Change MapVector's default template parameter to SmallVector<*, 0>

SmallVector<*, 0> is often a better replacement for std::vector :
both the object size and the code size are smaller.
(SmallMapVector uses SmallVector as well, but it is not common.)

clang size decreases by 0.0226%.
instructions:u decreases 0.037% when compiling a sqlite3 amalgram.

Reviewed By: JDevlieghere

Differential Revision: https://reviews.llvm.org/D156016

1 files changed, 1 insertions, 1 deletions

diff --git a/lld/MachO/UnwindInfoSection.cpp b/lld/MachO/UnwindInfoSection.cpp
index 0bffce0..1466e7b 100644
--- a/lld/MachO/UnwindInfoSection.cpp
+++ b/lld/MachO/UnwindInfoSection.cpp
@@ -146,7 +146,7 @@ private:
   Symbol *canonicalizePersonality(Symbol *);
 
   uint64_t unwindInfoSize = 0;
-  std::vector<decltype(symbols)::value_type> symbolsVec;
+  SmallVector<decltype(symbols)::value_type, 0> symbolsVec;
   CompactUnwindLayout cuLayout;
   std::vector<std::pair<compact_unwind_encoding_t, size_t>> commonEncodings;
   EncodingMap commonEncodingIndexes;