Encapsulate the DWARF string pool in a separate type.

Pulls out some more code from some of the rather monolithic DWARF
classes. Unlike the address table, the string table won't move up into
DwarfDebug - each DWARF file has its own string table (but there can be
only one address table).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207277 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/AsmPrinter/DwarfStringPool.h

@@ -0,0 +1,55 @@
+//===-- llvm/CodeGen/DwarfStringPool.h - Dwarf Debug Framework -*- C++ -*--===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef CODEGEN_ASMPRINTER_STRINGPOOL_H__
+#define CODEGEN_ASMPRINTER_STRINGPOOL_H__
+
+#include "llvm/ADT/StringMap.h"
+#include "llvm/CodeGen/AsmPrinter.h"
+#include "llvm/Support/Allocator.h"
+
+#include <utility>
+
+namespace llvm {
+
+class MCSymbol;
+class MCSection;
+class StringRef;
+
+// Collection of strings for this unit and assorted symbols.
+// A String->Symbol mapping of strings used by indirect
+// references.
+class DwarfStringPool {
+  StringMap<std::pair<MCSymbol *, unsigned>, BumpPtrAllocator &> Pool;
+  StringRef Prefix;
+  MCSymbol *SectionSymbol;
+
+public:
+  DwarfStringPool(BumpPtrAllocator &A, AsmPrinter &Asm, StringRef Prefix)
+      : Pool(A), Prefix(Prefix), SectionSymbol(Asm.GetTempSymbol(Prefix)) {}
+
+  void emit(AsmPrinter &Asm, const MCSection *StrSection,
+            const MCSection *OffsetSection = nullptr,
+            const MCSymbol *StrSecSym = nullptr);
+
+  /// \brief Returns the entry into the start of the pool.
+  MCSymbol *getSectionSymbol();
+
+  /// \brief Returns an entry into the string pool with the given
+  /// string text.
+  MCSymbol *getSymbol(AsmPrinter &Asm, StringRef Str);
+
+  /// \brief Returns the index into the string pool with the given
+  /// string text.
+  unsigned getIndex(AsmPrinter &Asm, StringRef Str);
+
+  bool empty() const { return Pool.empty(); }
+};
+}
+#endif