From 4bb7883d097f324d8c1d5f9f50e09c7471340abe Mon Sep 17 00:00:00 2001
From: Sam McCall <sam.mccall@gmail.com>
Date: Mon, 23 Jul 2018 10:44:40 +0000
Subject: [Support] Add a UniqueStringSaver: like StringSaver, but
 deduplicating.

Summary: Clarify contract of StringSaver (it null-terminates, callers rely on it).

Reviewers: hokein

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D49596

llvm-svn: 337677
---
 llvm/lib/Support/StringSaver.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

(limited to 'llvm/lib/Support/StringSaver.cpp')

diff --git a/llvm/lib/Support/StringSaver.cpp b/llvm/lib/Support/StringSaver.cpp
index 335fce3a7bb..1ded2bdb09d 100644
--- a/llvm/lib/Support/StringSaver.cpp
+++ b/llvm/lib/Support/StringSaver.cpp
@@ -17,3 +17,10 @@ StringRef StringSaver::save(StringRef S) {
   P[S.size()] = '\0';
   return StringRef(P, S.size());
 }
+
+StringRef UniqueStringSaver::save(StringRef S) {
+  auto R = Unique.insert(S);
+  if (R.second)                 // cache miss, need to actually save the string
+    *R.first = Strings.save(S); // safe replacement with equal value
+  return *R.first;
+}
-- 
cgit v1.2.3