[PATCH v2 2/5] [gdb] Make addrmap_mutable::insert_empty return bool

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

Function addrmap_mutable::set_empty has the follow behavior (shortened
comment):
...
/* In the mutable address map MAP, associate the addresses from START
   to END_INCLUSIVE that are currently associated with NULL with OBJ
   instead.  Addresses mapped to an object other than NULL are left
   unchanged.  */
  void set_empty (CORE_ADDR start, CORE_ADDR end_inclusive,
		  void *obj);
...

Change the return type to bool, and return true if the full range
[START, END_INCLUSIVE] is mapped to OBJ.

Tested on x86_64-linux.
---
 gdb/addrmap.c | 23 ++++++++++++++++++-----
 gdb/addrmap.h |  4 ++--
 2 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/gdb/addrmap.c b/gdb/addrmap.c
index 45493509f21..5fddc3c32b7 100644
--- a/gdb/addrmap.c
+++ b/gdb/addrmap.c
@@ -201,10 +201,11 @@ xfree_wrapper (splay_tree_key key)
   xfree ((void *) key);
 }
 
-void
+bool
 addrmap_mutable::set_empty (CORE_ADDR start, CORE_ADDR end_inclusive,
 			    void *obj)
 {
+  bool full_range = true;
   splay_tree_node n, next;
   void *prior_value;
 
@@ -234,8 +235,14 @@ addrmap_mutable::set_empty (CORE_ADDR start, CORE_ADDR end_inclusive,
        n && addrmap_node_key (n) <= end_inclusive;
        n = splay_tree_successor (addrmap_node_key (n)))
     {
-      if (! addrmap_node_value (n))
-	addrmap_node_set_value (n, obj);
+      if (addrmap_node_value (n))
+	{
+	  /* Already mapped.  */
+	  full_range = false;
+	  continue;
+	}
+
+      addrmap_node_set_value (n, obj);
     }
 
   /* Walk the area again, removing transitions from any value to
@@ -254,6 +261,8 @@ addrmap_mutable::set_empty (CORE_ADDR start, CORE_ADDR end_inclusive,
       else
 	prior_value = addrmap_node_value (n);
     }
+
+  return full_range;
 }
 
 
@@ -433,7 +442,9 @@ test_addrmap ()
   check_addrmap_find (map, array, 0, 19, nullptr);
 
   /* Insert address range into mutable addrmap.  */
-  map.set_empty (core_addr (&array[10]), core_addr (&array[12]), val1);
+  bool full_range_p
+    = map.set_empty (core_addr (&array[10]), core_addr (&array[12]), val1);
+  SELF_CHECK (full_range_p);
   check_addrmap_find (map, array, 0, 9, nullptr);
   check_addrmap_find (map, array, 10, 12, val1);
   check_addrmap_find (map, array, 13, 19, nullptr);
@@ -469,7 +480,9 @@ test_addrmap ()
   check_addrmap_find (*map2, array, 14, 19, nullptr);
 
   /* Insert partially overlapping address range into mutable addrmap.  */
-  map.set_empty (core_addr (&array[11]), core_addr (&array[13]), val2);
+  full_range_p
+    = map.set_empty (core_addr (&array[11]), core_addr (&array[13]), val2);
+  SELF_CHECK (!full_range_p);
   check_addrmap_find (map, array, 0, 9, nullptr);
   check_addrmap_find (map, array, 10, 12, val1);
   check_addrmap_find (map, array, 13, 13, val2);
diff --git a/gdb/addrmap.h b/gdb/addrmap.h
index 179e1f86668..398bdd84215 100644
--- a/gdb/addrmap.h
+++ b/gdb/addrmap.h
@@ -152,7 +152,7 @@ struct addrmap_mutable final : public addrmap
   /* In the mutable address map MAP, associate the addresses from START
      to END_INCLUSIVE that are currently associated with NULL with OBJ
      instead.  Addresses mapped to an object other than NULL are left
-     unchanged.
+     unchanged.  Return true if the full range is mapped to OBJ.
 
      As the name suggests, END_INCLUSIVE is also mapped to OBJ.  This
      convention is unusual, but it allows callers to accurately specify
@@ -186,7 +186,7 @@ struct addrmap_mutable final : public addrmap
      semantics than to provide an interface which allows it to be
      implemented efficiently, but doesn't reveal too much of the
      representation.  */
-  void set_empty (CORE_ADDR start, CORE_ADDR end_inclusive,
+  bool set_empty (CORE_ADDR start, CORE_ADDR end_inclusive,
 		  void *obj);
 
   /* Clear this addrmap.  */
-- 
2.43.0