[DWARF] Revert r345546: Refactor range list extraction and dumping

This patch caused some internal tests to break which are being investigated.

llvm-svn: 345687
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFDebugRangeList.cpp b/llvm/lib/DebugInfo/DWARF/DWARFDebugRangeList.cpp
new file mode 100644
index 0000000..dfb9130
--- /dev/null
+++ b/llvm/lib/DebugInfo/DWARF/DWARFDebugRangeList.cpp
@@ -0,0 +1,96 @@
+//===- DWARFDebugRangesList.cpp -------------------------------------------===//
+//
+//                     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/DWARFDebugRangeList.h"
+#include "llvm/DebugInfo/DWARF/DWARFContext.h"
+#include "llvm/Support/Errc.h"
+#include "llvm/Support/Format.h"
+#include "llvm/Support/raw_ostream.h"
+#include <cinttypes>
+#include <cstdint>
+
+using namespace llvm;
+
+void DWARFDebugRangeList::clear() {
+  Offset = -1U;
+  AddressSize = 0;
+  Entries.clear();
+}
+
+Error DWARFDebugRangeList::extract(const DWARFDataExtractor &data,
+                                   uint32_t *offset_ptr) {
+  clear();
+  if (!data.isValidOffset(*offset_ptr))
+    return createStringError(errc::invalid_argument,
+                       "invalid range list offset 0x%" PRIx32, *offset_ptr);
+
+  AddressSize = data.getAddressSize();
+  if (AddressSize != 4 && AddressSize != 8)
+    return createStringError(errc::invalid_argument,
+                       "invalid address size: %" PRIu8, AddressSize);
+  Offset = *offset_ptr;
+  while (true) {
+    RangeListEntry Entry;
+    Entry.SectionIndex = -1ULL;
+
+    uint32_t prev_offset = *offset_ptr;
+    Entry.StartAddress = data.getRelocatedAddress(offset_ptr);
+    Entry.EndAddress =
+        data.getRelocatedAddress(offset_ptr, &Entry.SectionIndex);
+
+    // Check that both values were extracted correctly.
+    if (*offset_ptr != prev_offset + 2 * AddressSize) {
+      clear();
+      return createStringError(errc::invalid_argument,
+                         "invalid range list entry at offset 0x%" PRIx32,
+                         prev_offset);
+    }
+    if (Entry.isEndOfListEntry())
+      break;
+    Entries.push_back(Entry);
+  }
+  return Error::success();
+}
+
+void DWARFDebugRangeList::dump(raw_ostream &OS) const {
+  for (const RangeListEntry &RLE : Entries) {
+    const char *format_str = (AddressSize == 4
+                              ? "%08x %08"  PRIx64 " %08"  PRIx64 "\n"
+                              : "%08x %016" PRIx64 " %016" PRIx64 "\n");
+    OS << format(format_str, Offset, RLE.StartAddress, RLE.EndAddress);
+  }
+  OS << format("%08x <End of list>\n", Offset);
+}
+
+DWARFAddressRangesVector DWARFDebugRangeList::getAbsoluteRanges(
+    llvm::Optional<SectionedAddress> BaseAddr) const {
+  DWARFAddressRangesVector Res;
+  for (const RangeListEntry &RLE : Entries) {
+    if (RLE.isBaseAddressSelectionEntry(AddressSize)) {
+      BaseAddr = {RLE.EndAddress, RLE.SectionIndex};
+      continue;
+    }
+
+    DWARFAddressRange E;
+    E.LowPC = RLE.StartAddress;
+    E.HighPC = RLE.EndAddress;
+    E.SectionIndex = RLE.SectionIndex;
+    // Base address of a range list entry is determined by the closest preceding
+    // base address selection entry in the same range list. It defaults to the
+    // base address of the compilation unit if there is no such entry.
+    if (BaseAddr) {
+      E.LowPC += BaseAddr->Address;
+      E.HighPC += BaseAddr->Address;
+      if (E.SectionIndex == -1ULL)
+        E.SectionIndex = BaseAddr->SectionIndex;
+    }
+    Res.push_back(E);
+  }
+  return Res;
+}