1 files changed, 140 insertions, 0 deletions
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugArangeSet.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugArangeSet.cpp
new file mode 100644
index 000000000000..86ce3b329b25
--- /dev/null
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugArangeSet.cpp
@@ -0,0 +1,140 @@
+//===-- DWARFDebugArangeSet.cpp ---------------------------------*- C++ -*-===//
+//
+// 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 "DWARFDebugArangeSet.h"
+#include "DWARFDataExtractor.h"
+#include "llvm/Object/Error.h"
+#include <cassert>
+
+using namespace lldb_private;
+
+DWARFDebugArangeSet::DWARFDebugArangeSet()
+    : m_offset(DW_INVALID_OFFSET), m_header(), m_arange_descriptors() {
+  m_header.length = 0;
+  m_header.version = 0;
+  m_header.cu_offset = 0;
+  m_header.addr_size = 0;
+  m_header.seg_size = 0;
+}
+
+void DWARFDebugArangeSet::Clear() {
+  m_offset = DW_INVALID_OFFSET;
+  m_header.length = 0;
+  m_header.version = 0;
+  m_header.cu_offset = 0;
+  m_header.addr_size = 0;
+  m_header.seg_size = 0;
+  m_arange_descriptors.clear();
+}
+
+llvm::Error DWARFDebugArangeSet::extract(const DWARFDataExtractor &data,
+                                         lldb::offset_t *offset_ptr) {
+  assert(data.ValidOffset(*offset_ptr));
+
+  m_arange_descriptors.clear();
+  m_offset = *offset_ptr;
+
+  // 7.20 Address Range Table
+  //
+  // Each set of entries in the table of address ranges contained in the
+  // .debug_aranges section begins with a header consisting of: a 4-byte
+  // length containing the length of the set of entries for this compilation
+  // unit, not including the length field itself; a 2-byte version identifier
+  // containing the value 2 for DWARF Version 2; a 4-byte offset into
+  // the.debug_infosection; a 1-byte unsigned integer containing the size in
+  // bytes of an address (or the offset portion of an address for segmented
+  // addressing) on the target system; and a 1-byte unsigned integer
+  // containing the size in bytes of a segment descriptor on the target
+  // system. This header is followed by a series of tuples. Each tuple
+  // consists of an address and a length, each in the size appropriate for an
+  // address on the target architecture.
+  m_header.length = data.GetDWARFInitialLength(offset_ptr);
+  m_header.version = data.GetU16(offset_ptr);
+  m_header.cu_offset = data.GetDWARFOffset(offset_ptr);
+  m_header.addr_size = data.GetU8(offset_ptr);
+  m_header.seg_size = data.GetU8(offset_ptr);
+
+  // Try to avoid reading invalid arange sets by making sure:
+  // 1 - the version looks good
+  // 2 - the address byte size looks plausible
+  // 3 - the length seems to make sense
+  // size looks plausible
+  if (m_header.version < 2 || m_header.version > 5)
+    return llvm::make_error<llvm::object::GenericBinaryError>(
+        "Invalid arange header version");
+
+  if (m_header.addr_size != 4 && m_header.addr_size != 8)
+    return llvm::make_error<llvm::object::GenericBinaryError>(
+        "Invalid arange header address size");
+
+  if (m_header.length == 0)
+    return llvm::make_error<llvm::object::GenericBinaryError>(
+        "Invalid arange header length");
+
+  if (!data.ValidOffset(m_offset + sizeof(m_header.length) + m_header.length -
+                        1))
+    return llvm::make_error<llvm::object::GenericBinaryError>(
+        "Invalid arange header length");
+
+  // The first tuple following the header in each set begins at an offset
+  // that is a multiple of the size of a single tuple (that is, twice the
+  // size of an address). The header is padded, if necessary, to the
+  // appropriate boundary.
+  const uint32_t header_size = *offset_ptr - m_offset;
+  const uint32_t tuple_size = m_header.addr_size << 1;
+  uint32_t first_tuple_offset = 0;
+  while (first_tuple_offset < header_size)
+    first_tuple_offset += tuple_size;
+
+  *offset_ptr = m_offset + first_tuple_offset;
+
+  Descriptor arangeDescriptor;
+
+  static_assert(sizeof(arangeDescriptor.address) ==
+                    sizeof(arangeDescriptor.length),
+                "DWARFDebugArangeSet::Descriptor.address and "
+                "DWARFDebugArangeSet::Descriptor.length must have same size");
+
+  while (data.ValidOffset(*offset_ptr)) {
+    arangeDescriptor.address = data.GetMaxU64(offset_ptr, m_header.addr_size);
+    arangeDescriptor.length = data.GetMaxU64(offset_ptr, m_header.addr_size);
+
+    // Each set of tuples is terminated by a 0 for the address and 0 for
+    // the length.
+    if (!arangeDescriptor.address && !arangeDescriptor.length)
+      return llvm::ErrorSuccess();
+
+    m_arange_descriptors.push_back(arangeDescriptor);
+  }
+
+  return llvm::make_error<llvm::object::GenericBinaryError>(
+      "arange descriptors not terminated by null entry");
+}
+
+class DescriptorContainsAddress {
+public:
+  DescriptorContainsAddress(dw_addr_t address) : m_address(address) {}
+  bool operator()(const DWARFDebugArangeSet::Descriptor &desc) const {
+    return (m_address >= desc.address) &&
+           (m_address < (desc.address + desc.length));
+  }
+
+private:
+  const dw_addr_t m_address;
+};
+
+dw_offset_t DWARFDebugArangeSet::FindAddress(dw_addr_t address) const {
+  DescriptorConstIter end = m_arange_descriptors.end();
+  DescriptorConstIter pos =
+      std::find_if(m_arange_descriptors.begin(), end,   // Range
+                   DescriptorContainsAddress(address)); // Predicate
+  if (pos != end)
+    return m_header.cu_offset;
+
+  return DW_INVALID_OFFSET;
+}