From b2e78a061c06546c42a977071047cd9da2194a32 Mon Sep 17 00:00:00 2001
From: serge-sans-paille <sguelton@redhat.com>
Date: Mon, 8 Mar 2021 17:46:35 +0100
Subject: [PATCH] [NFC] Use SmallString instead of std::string for the
 AttrBuilder

This avoids a few unnecessary conversion from StringRef to std::string, and a
bunch of extra allocation thanks to the SmallString.

Differential Revision: https://reviews.llvm.org/D98190
---
 llvm/include/llvm/IR/Attributes.h | 5 +++--
 llvm/lib/IR/Attributes.cpp        | 2 +-
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/llvm/include/llvm/IR/Attributes.h b/llvm/include/llvm/IR/Attributes.h
index b405654..20f5cf1 100644
--- a/llvm/include/llvm/IR/Attributes.h
+++ b/llvm/include/llvm/IR/Attributes.h
@@ -18,6 +18,7 @@
 #include "llvm-c/Types.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/Optional.h"
+#include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/iterator_range.h"
 #include "llvm/Config/llvm-config.h"
@@ -756,7 +757,7 @@ template <> struct DenseMapInfo<AttributeList> {
 /// equality, presence of attributes, etc.
 class AttrBuilder {
   std::bitset<Attribute::EndAttrKinds> Attrs;
-  std::map<std::string, std::string, std::less<>> TargetDepAttrs;
+  std::map<SmallString<32>, SmallString<32>, std::less<>> TargetDepAttrs;
   MaybeAlign Alignment;
   MaybeAlign StackAlignment;
   uint64_t DerefBytes = 0;
@@ -921,7 +922,7 @@ public:
   bool empty() const { return Attrs.none(); }
 
   // Iterators for target-dependent attributes.
-  using td_type = std::pair<std::string, std::string>;
+  using td_type = decltype(TargetDepAttrs)::value_type;
   using td_iterator = decltype(TargetDepAttrs)::iterator;
   using td_const_iterator = decltype(TargetDepAttrs)::const_iterator;
   using td_range = iterator_range<td_iterator>;
diff --git a/llvm/lib/IR/Attributes.cpp b/llvm/lib/IR/Attributes.cpp
index c98e5c3..18c2f3a 100644
--- a/llvm/lib/IR/Attributes.cpp
+++ b/llvm/lib/IR/Attributes.cpp
@@ -1624,7 +1624,7 @@ AttrBuilder &AttrBuilder::addAttribute(Attribute Attr) {
 }
 
 AttrBuilder &AttrBuilder::addAttribute(StringRef A, StringRef V) {
-  TargetDepAttrs[std::string(A)] = std::string(V);
+  TargetDepAttrs[A] = V;
   return *this;
 }
 
-- 
2.7.4