1 files changed, 140 insertions, 0 deletions
diff --git a/lib/DebugInfo/DWARFDebugArangeSet.cpp b/lib/DebugInfo/DWARFDebugArangeSet.cpp
new file mode 100644
index 0000000000..76e02f70d8
--- /dev/null
+++ b/lib/DebugInfo/DWARFDebugArangeSet.cpp
@@ -0,0 +1,140 @@
+//===-- DWARFDebugArangeSet.cpp -------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "DWARFDebugArangeSet.h"
+#include "llvm/Support/Format.h"
+#include "llvm/Support/raw_ostream.h"
+#include <cassert>
+using namespace llvm;
+
+void DWARFDebugArangeSet::clear() {
+  Offset = -1U;
+  std::memset(&Header, 0, sizeof(Header));
+  ArangeDescriptors.clear();
+}
+
+void DWARFDebugArangeSet::compact() {
+  if (ArangeDescriptors.empty())
+    return;
+
+  // Iterate through all arange descriptors and combine any ranges that
+  // overlap or have matching boundaries. The ArangeDescriptors are assumed
+  // to be in ascending order.
+  uint32_t i = 0;
+  while (i + 1 < ArangeDescriptors.size()) {
+    if (ArangeDescriptors[i].getEndAddress() >= ArangeDescriptors[i+1].Address){
+      // The current range ends at or exceeds the start of the next address
+      // range. Compute the max end address between the two and use that to
+      // make the new length.
+      const uint64_t max_end_addr =
+        std::max(ArangeDescriptors[i].getEndAddress(),
+                 ArangeDescriptors[i+1].getEndAddress());
+      ArangeDescriptors[i].Length = max_end_addr - ArangeDescriptors[i].Address;
+      // Now remove the next entry as it was just combined with the previous one
+      ArangeDescriptors.erase(ArangeDescriptors.begin()+i+1);
+    } else {
+      // Discontiguous address range, just proceed to the next one.
+      ++i;
+    }
+  }
+}
+
+bool
+DWARFDebugArangeSet::extract(DataExtractor data, uint32_t *offset_ptr) {
+  if (data.isValidOffset(*offset_ptr)) {
+    ArangeDescriptors.clear();
+    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.
+    Header.Length = data.getU32(offset_ptr);
+    Header.Version = data.getU16(offset_ptr);
+    Header.CuOffset = data.getU32(offset_ptr);
+    Header.AddrSize = data.getU8(offset_ptr);
+    Header.SegSize = data.getU8(offset_ptr);
+
+    // 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 - Offset;
+    const uint32_t tuple_size = Header.AddrSize * 2;
+    uint32_t first_tuple_offset = 0;
+    while (first_tuple_offset < header_size)
+      first_tuple_offset += tuple_size;
+
+    *offset_ptr = Offset + first_tuple_offset;
+
+    Descriptor arangeDescriptor;
+
+    assert(sizeof(arangeDescriptor.Address) == sizeof(arangeDescriptor.Length));
+    assert(sizeof(arangeDescriptor.Address) >= Header.AddrSize);
+
+    while (data.isValidOffset(*offset_ptr)) {
+      arangeDescriptor.Address = data.getUnsigned(offset_ptr, Header.AddrSize);
+      arangeDescriptor.Length = data.getUnsigned(offset_ptr, Header.AddrSize);
+
+      // Each set of tuples is terminated by a 0 for the address and 0
+      // for the length.
+      if (arangeDescriptor.Address || arangeDescriptor.Length)
+        ArangeDescriptors.push_back(arangeDescriptor);
+      else
+        break; // We are done if we get a zero address and length
+    }
+
+    return !ArangeDescriptors.empty();
+  }
+  return false;
+}
+
+void DWARFDebugArangeSet::dump(raw_ostream &OS) const {
+  OS << format("Address Range Header: length = 0x%8.8x, version = 0x%4.4x, ",
+               Header.Length, Header.Version)
+     << format("cu_offset = 0x%8.8x, addr_size = 0x%2.2x, seg_size = 0x%2.2x\n",
+               Header.CuOffset, Header.AddrSize, Header.SegSize);
+
+  const uint32_t hex_width = Header.AddrSize * 2;
+  for (DescriptorConstIter pos = ArangeDescriptors.begin(),
+       end = ArangeDescriptors.end(); pos != end; ++pos)
+    OS << format("[0x%*.*llx -", hex_width, hex_width, pos->Address)
+       << format(" 0x%*.*llx)\n", hex_width, hex_width, pos->getEndAddress());
+}
+
+
+class DescriptorContainsAddress {
+  const uint64_t Address;
+public:
+  DescriptorContainsAddress(uint64_t address) : Address(address) {}
+  bool operator()(const DWARFDebugArangeSet::Descriptor &desc) const {
+    return Address >= desc.Address && Address < (desc.Address + desc.Length);
+  }
+};
+
+uint32_t DWARFDebugArangeSet::findAddress(uint64_t address) const {
+  DescriptorConstIter end = ArangeDescriptors.end();
+  DescriptorConstIter pos =
+    std::find_if(ArangeDescriptors.begin(), end, // Range
+                 DescriptorContainsAddress(address)); // Predicate
+  if (pos != end)
+    return Header.CuOffset;
+
+  return -1U;
+}