Adding a StringPool data structure, which GC will use.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44705 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Support/StringPool.cpp

@@ -0,0 +1,35 @@
+//===-- StringPool.cpp - Interned string pool -----------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by Gordon Henriksen and is distributed under the
+// University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the StringPool class.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/StringPool.h"
+#include "llvm/Support/Streams.h"
+
+using namespace llvm;
+
+StringPool::StringPool() {}
+
+StringPool::~StringPool() {
+  assert(InternTable.empty() && "PooledStringPtr leaked!");
+}
+
+PooledStringPtr StringPool::intern(const char *Begin, const char *End) {
+  table_t::iterator I = InternTable.find(Begin, End);
+  if (I != InternTable.end())
+    return PooledStringPtr(&*I);
+  
+  entry_t *S = entry_t::Create(Begin, End);
+  S->getValue().Pool = this;
+  InternTable.insert(S);
+  
+  return PooledStringPtr(S);
+}