Replace a hand-written suffix compare with std::lexicographical_compare.

No functionality change.

llvm-svn: 218380

1 files changed, 6 insertions, 14 deletions

diff --git a/llvm/lib/MC/StringTableBuilder.cpp b/llvm/lib/MC/StringTableBuilder.cpp
index db58ece5c86..2343845ee32 100644
--- a/llvm/lib/MC/StringTableBuilder.cpp
+++ b/llvm/lib/MC/StringTableBuilder.cpp
@@ -12,25 +12,17 @@
 
 using namespace llvm;
 
-static bool compareBySuffix(StringRef a, StringRef b) {
-  size_t sizeA = a.size();
-  size_t sizeB = b.size();
-  size_t len = std::min(sizeA, sizeB);
-  for (size_t i = 0; i < len; ++i) {
-    char ca = a[sizeA - i - 1];
-    char cb = b[sizeB - i - 1];
-    if (ca != cb)
-      return ca > cb;
-  }
-  return sizeA > sizeB;
-}
-
 void StringTableBuilder::finalize() {
   SmallVector<StringRef, 8> Strings;
   for (auto i = StringIndexMap.begin(), e = StringIndexMap.end(); i != e; ++i)
     Strings.push_back(i->getKey());
 
-  std::sort(Strings.begin(), Strings.end(), compareBySuffix);
+  // Sort the vector so a string is sorted above its suffixes.
+  std::sort(Strings.begin(), Strings.end(), [](StringRef A, StringRef B) {
+    typedef std::reverse_iterator<StringRef::iterator> Reverse;
+    return !std::lexicographical_compare(Reverse(A.end()), Reverse(A.begin()),
+                                         Reverse(B.end()), Reverse(B.begin()));
+  });
 
   // FIXME: Starting with a null byte is ELF specific. Generalize this so we
   // can use the class with other object formats.