[PATCH v2 5/7] [gdb] Add prev/next params to find_pc_section

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

Now that we're using std::lower_bound to find sections in find_pc_section,
extend find_pc_section to return the previous and next section in case it
returns nullptr.
---
 gdb/objfiles.c | 32 ++++++++++++++++++++++++++++++--
 gdb/objfiles.h |  4 +++-
 2 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/gdb/objfiles.c b/gdb/objfiles.c
index 066d1af9b9e..3871ef1670f 100644
--- a/gdb/objfiles.c
+++ b/gdb/objfiles.c
@@ -912,14 +912,22 @@ update_section_map (struct program_space *pspace,
   *pmap_size = map_size;
 }
 
-/* Returns a section whose range includes PC or NULL if none found.   */
+/* Returns a section whose range includes PC or nullptr if none found.
+   On returning nullptr, set PREV_PTR and NEXT_PTR to point to the sections
+   before and after PC, if any.  */
 
 struct obj_section *
-find_pc_section (CORE_ADDR pc)
+find_pc_section (CORE_ADDR pc, struct obj_section **prev_ptr,
+		 struct obj_section **next_ptr)
 {
   struct objfile_pspace_info *pspace_info;
   struct obj_section *s;
 
+  if (prev_ptr != nullptr)
+    *prev_ptr = nullptr;
+  if (next_ptr != nullptr)
+    *next_ptr = nullptr;
+
   /* Check for mapped overlay section first.  */
   s = find_pc_mapped_section (pc);
   if (s)
@@ -964,6 +972,26 @@ find_pc_section (CORE_ADDR pc)
       && (*it)->addr () <= pc && pc < (*it)->endaddr ())
     return *it;
 
+  struct obj_section *prev = nullptr, *next = nullptr;
+  auto prev_it = (it == data.cbegin ()
+		  ? data.cend ()
+		  : it - 1);
+  if (prev_it != data.cend ())
+    {
+      prev = *prev_it;
+      gdb_assert (prev->endaddr () <= pc);
+    }
+  if (it != data.cend ())
+    {
+      next = *it;
+      gdb_assert (pc < next->addr ());
+    }
+
+  if (prev_ptr != nullptr)
+    *prev_ptr = prev;
+  if (next_ptr != nullptr)
+    *next_ptr = next;
+
   return NULL;
 }
 
diff --git a/gdb/objfiles.h b/gdb/objfiles.h
index fa265f83b79..d23e2b3046e 100644
--- a/gdb/objfiles.h
+++ b/gdb/objfiles.h
@@ -954,7 +954,9 @@ extern void objfile_purge_solibs (program_space *pspace);
 /* Functions for dealing with the minimal symbol table, really a misc
    address<->symbol mapping for things we don't have debug symbols for.  */
 
-extern struct obj_section *find_pc_section (CORE_ADDR pc);
+extern struct obj_section *find_pc_section (CORE_ADDR pc,
+					    struct obj_section **prev = nullptr,
+					    struct obj_section **next = nullptr);
 
 /* Return true if PC is in a section called NAME.  */
 extern bool pc_in_section (CORE_ADDR, const char *);
-- 
2.51.0