LibDebug: Support parsing non-contiguous DWARF address ranges

This adds support for parsing DWARF "range lists", which are identified
by the DW_AT_ranges form.

They contain code addresses for DIEs whose location is not contiguous.

Userland/Libraries/LibDebug/Dwarf/AddressRanges.h

@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2020-2021, Itamar S. <itamar8910@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include "CompilationUnit.h"
+#include <AK/Forward.h>
+#include <AK/Function.h>
+#include <AK/MemoryStream.h>
+#include <AK/Noncopyable.h>
+
+namespace Debug::Dwarf {
+
+class AddressRanges {
+    AK_MAKE_NONCOPYABLE(AddressRanges);
+    AK_MAKE_NONMOVABLE(AddressRanges);
+
+public:
+    AddressRanges(ReadonlyBytes range_lists_data, size_t offset, CompilationUnit const& compilation_unit);
+
+    struct Range {
+        FlatPtr start { 0 };
+        FlatPtr end { 0 };
+    };
+    void for_each_range(Function<void(Range)>);
+
+private:
+    InputMemoryStream m_range_lists_stream;
+    CompilationUnit const& m_compilation_unit;
+};
+
+}