[PATCH 4/7] [gdb] Add block::superblocks

[Tom de Vries <tdevries@suse.de>]

Add a function block::superblocks that can be used to transform:
...
  while (block != NULL)
    {
      ...
      block = block->superblock ();
    }
...
into:
...
  for (auto b : block::super_blocks (block))
    {
      ...
    }
...

I'm not sure about the name.  It might suggest that block is not included in
the iteration, but in fact it is.

I considered block::block_and_supers () instead, but it seems a bit awkward.
---
 gdb/block.h | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/gdb/block.h b/gdb/block.h
index 091120ae2b8..4a1db79d7ed 100644
--- a/gdb/block.h
+++ b/gdb/block.h
@@ -108,6 +108,27 @@ struct blockranges
 
 struct block : public allocate_on_obstack<block>
 {
+  /* Variant of next_iterator using the superblock field instead of next.  */
+  struct superblock_iterator : base_next_iterator<const block>
+  {
+    typedef superblock_iterator self_type;
+
+    explicit superblock_iterator (value_type item)
+      : base_next_iterator (item)
+    {
+    }
+
+    superblock_iterator () = default;
+
+    self_type &operator++ ()
+    {
+      this->m_item = this->m_item->superblock ();
+      return *this;
+    }
+  };
+
+  using superblock_range = iterator_range<superblock_iterator>;
+
   /* Return this block's start address.  */
   CORE_ADDR start () const
   { return m_start; }
@@ -306,6 +327,21 @@ struct block : public allocate_on_obstack<block>
 
   struct dynamic_prop *static_link () const;
 
+  superblock_range super_blocks () const
+  {
+    superblock_range::iterator begin (this);
+
+    return superblock_range (std::move (begin));
+  }
+
+  static superblock_range super_blocks (const block *b)
+  {
+    if (b == nullptr)
+      return superblock_range ();
+
+    return b->super_blocks ();
+  }
+
   /* Return true if block A is lexically nested within this block, or
      if A and this block have the same pc range.  Return false
      otherwise.  If ALLOW_NESTED is true, then block A is considered
-- 
2.51.0