1 files changed, 122 insertions, 0 deletions
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFDebugAranges.cpp b/llvm/lib/DebugInfo/DWARF/DWARFDebugAranges.cpp
new file mode 100644
index 0000000000000..ca6043109cdb8
--- /dev/null
+++ b/llvm/lib/DebugInfo/DWARF/DWARFDebugAranges.cpp
@@ -0,0 +1,122 @@
+//===- DWARFDebugAranges.cpp ----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#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/DataExtractor.h"
+#include "llvm/Support/WithColor.h"
+#include <algorithm>
+#include <cassert>
+#include <cstdint>
+#include <set>
+#include <vector>
+
+using namespace llvm;
+
+void DWARFDebugAranges::extract(DataExtractor DebugArangesData) {
+  if (!DebugArangesData.isValidOffset(0))
+    return;
+  uint64_t Offset = 0;
+  DWARFDebugArangeSet Set;
+
+  while (Set.extract(DebugArangesData, &Offset)) {
+    uint64_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->getDWARFObj().getArangesSection(),
+                            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()) {
+    uint64_t CUOffset = CU->getOffset();
+    if (ParsedCUOffsets.insert(CUOffset).second) {
+      Expected<DWARFAddressRangesVector> CURanges = CU->collectAddressRanges();
+      if (!CURanges)
+        WithColor::error() << toString(CURanges.takeError()) << '\n';
+      else
+        for (const auto &R : *CURanges)
+          appendRange(CUOffset, R.LowPC, R.HighPC);
+    }
+  }
+
+  construct();
+}
+
+void DWARFDebugAranges::clear() {
+  Endpoints.clear();
+  Aranges.clear();
+  ParsedCUOffsets.clear();
+}
+
+void DWARFDebugAranges::appendRange(uint64_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<uint64_t> ValidCUs;  // Maintain the set of CUs describing
+                                     // a current address range.
+  llvm::sort(Endpoints);
+  uint64_t PrevAddress = -1ULL;
+  for (const auto &E : Endpoints) {
+    if (PrevAddress < E.Address && !ValidCUs.empty()) {
+      // 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.
+  Endpoints.clear();
+  Endpoints.shrink_to_fit();
+}
+
+uint32_t DWARFDebugAranges::findAddress(uint64_t Address) const {
+  RangeCollIterator It =
+      partition_point(Aranges, [=](Range R) { return R.HighPC() <= Address; });
+  if (It != Aranges.end() && It->LowPC <= Address)
+    return It->CUOffset;
+  return -1U;
+}