Invert the MC -> Object dependency.

Now that we have a lib/MC/MCAnalysis, the dependency was there just because
of two helper classes. Move the two over to MC.

This will allow IRObjectFile to parse inline assembly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212248 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/MC/StringTableBuilder.h

@@ -0,0 +1,59 @@
+//===-- StringTableBuilder.h - String table building utility ------*- C++ -*-=//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_MC_STRINGTABLE_BUILDER_H
+#define LLVM_MC_STRINGTABLE_BUILDER_H
+
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/StringMap.h"
+#include <cassert>
+
+namespace llvm {
+
+/// \brief Utility for building string tables with deduplicated suffixes.
+class StringTableBuilder {
+  SmallString<256> StringTable;
+  StringMap<size_t> StringIndexMap;
+
+public:
+  /// \brief Add a string to the builder. Returns a StringRef to the internal
+  /// copy of s. Can only be used before the table is finalized.
+  StringRef add(StringRef s) {
+    assert(!isFinalized());
+    return StringIndexMap.GetOrCreateValue(s, 0).getKey();
+  }
+
+  /// \brief Analyze the strings and build the final table. No more strings can
+  /// be added after this point.
+  void finalize();
+
+  /// \brief Retrieve the string table data. Can only be used after the table
+  /// is finalized.
+  StringRef data() {
+    assert(isFinalized());
+    return StringTable;
+  }
+
+  /// \brief Get the offest of a string in the string table. Can only be used
+  /// after the table is finalized.
+  size_t getOffset(StringRef s) {
+    assert(isFinalized());
+    assert(StringIndexMap.count(s) && "String is not in table!");
+    return StringIndexMap[s];
+  }
+
+private:
+  bool isFinalized() {
+    return !StringTable.empty();
+  }
+};
+
+} // end llvm namespace
+
+#endif