--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/DebugInfo/DWARF/DWARFDebugAranges.cpp	Wed Feb 18 14:55:36 2015 +0900
@@ -0,0 +1,129 @@
+//===-- DWARFDebugAranges.cpp -----------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/DebugInfo/DWARF/DWARFDebugAranges.h"
+#include "llvm/DebugInfo/DWARF/DWARFCompileUnit.h"
+#include "llvm/DebugInfo/DWARF/DWARFContext.h"
+#include "llvm/DebugInfo/DWARF/DWARFDebugArangeSet.h"
+#include "llvm/Support/Format.h"
+#include "llvm/Support/raw_ostream.h"
+#include <algorithm>
+#include <cassert>
+#include <set>
+using namespace llvm;
+
+void DWARFDebugAranges::extract(DataExtractor DebugArangesData) {
+  if (!DebugArangesData.isValidOffset(0))
+    return;
+  uint32_t Offset = 0;
+  DWARFDebugArangeSet Set;
+
+  while (Set.extract(DebugArangesData, &Offset)) {
+    uint32_t CUOffset = Set.getCompileUnitDIEOffset();
+    for (const auto &Desc : Set.descriptors()) {
+      uint64_t LowPC = Desc.Address;
+      uint64_t HighPC = Desc.getEndAddress();
+      appendRange(CUOffset, LowPC, HighPC);
+    }
+    ParsedCUOffsets.insert(CUOffset);
+  }
+}
+
+void DWARFDebugAranges::generate(DWARFContext *CTX) {
+  clear();
+  if (!CTX)
+    return;
+
+  // Extract aranges from .debug_aranges section.
+  DataExtractor ArangesData(CTX->getARangeSection(), CTX->isLittleEndian(), 0);
+  extract(ArangesData);
+
+  // Generate aranges from DIEs: even if .debug_aranges section is present,
+  // it may describe only a small subset of compilation units, so we need to
+  // manually build aranges for the rest of them.
+  for (const auto &CU : CTX->compile_units()) {
+    uint32_t CUOffset = CU->getOffset();
+    if (ParsedCUOffsets.insert(CUOffset).second) {
+      DWARFAddressRangesVector CURanges;
+      CU->collectAddressRanges(CURanges);
+      for (const auto &R : CURanges) {
+        appendRange(CUOffset, R.first, R.second);
+      }
+    }
+  }
+
+  construct();
+}
+
+void DWARFDebugAranges::clear() {
+  Endpoints.clear();
+  Aranges.clear();
+  ParsedCUOffsets.clear();
+}
+
+void DWARFDebugAranges::appendRange(uint32_t CUOffset, uint64_t LowPC,
+                                    uint64_t HighPC) {
+  if (LowPC >= HighPC)
+    return;
+  Endpoints.emplace_back(LowPC, CUOffset, true);
+  Endpoints.emplace_back(HighPC, CUOffset, false);
+}
+
+void DWARFDebugAranges::construct() {
+  std::multiset<uint32_t> ValidCUs;  // Maintain the set of CUs describing
+                                     // a current address range.
+  std::sort(Endpoints.begin(), Endpoints.end());
+  uint64_t PrevAddress = -1ULL;
+  for (const auto &E : Endpoints) {
+    if (PrevAddress < E.Address && ValidCUs.size() > 0) {
+      // If the address range between two endpoints is described by some
+      // CU, first try to extend the last range in Aranges. If we can't
+      // do it, start a new range.
+      if (!Aranges.empty() && Aranges.back().HighPC() == PrevAddress &&
+          ValidCUs.find(Aranges.back().CUOffset) != ValidCUs.end()) {
+        Aranges.back().setHighPC(E.Address);
+      } else {
+        Aranges.emplace_back(PrevAddress, E.Address, *ValidCUs.begin());
+      }
+    }
+    // Update the set of valid CUs.
+    if (E.IsRangeStart) {
+      ValidCUs.insert(E.CUOffset);
+    } else {
+      auto CUPos = ValidCUs.find(E.CUOffset);
+      assert(CUPos != ValidCUs.end());
+      ValidCUs.erase(CUPos);
+    }
+    PrevAddress = E.Address;
+  }
+  assert(ValidCUs.empty());
+
+  // Endpoints are not needed now.
+  std::vector<RangeEndpoint> EmptyEndpoints;
+  EmptyEndpoints.swap(Endpoints);
+}
+
+uint32_t DWARFDebugAranges::findAddress(uint64_t Address) const {
+  if (!Aranges.empty()) {
+    Range range(Address);
+    RangeCollIterator begin = Aranges.begin();
+    RangeCollIterator end = Aranges.end();
+    RangeCollIterator pos =
+        std::lower_bound(begin, end, range);
+
+    if (pos != end && pos->containsAddress(Address)) {
+      return pos->CUOffset;
+    } else if (pos != begin) {
+      --pos;
+      if (pos->containsAddress(Address))
+        return pos->CUOffset;
+    }
+  }
+  return -1U;
+}