gdb: fix owner passed to remove_target_sections in clear_solib

Commit 8971d2788e7 ("gdb: link so_list using intrusive_list") introduced
a bug in clear_solib.  Instead of passing an `so_list *` to
remove_target_sections, it passed an `so_list **`.  This was not caught
by the compiler, because remove_target_sections takes a `void *` as the
"owner", so you can pass it any pointer and it won't complain.

This happened because I previously had a patch to change the type of the
disposer parameter to be a reference rather than a pointer, so had to
change `so` to `&so`.  When dropping that patch, I forgot to revert this
bit and / or it got re-introduced when handling subsequent merge
conflicts.  And I didn't properly retest.

Fix that, but try to make things less error prone.  Add a union to
represent the possible owner kinds for a target_section.  Trying to pass
a pointer to another type than those will not compile.

Change-Id: I600cab5ea0408ccc5638467b760768161ca3036c

1 files changed, 8 insertions, 8 deletions

diff --git a/gdb/exec.c b/gdb/exec.c
index 0f9f9d0..5956012 100644
--- a/gdb/exec.c
+++ b/gdb/exec.c
@@ -492,8 +492,8 @@ exec_file_attach (const char *filename, int from_tty)
       /* Add the executable's sections to the current address spaces'
 	 list of sections.  This possibly pushes the exec_ops
 	 target.  */
-      current_program_space->add_target_sections (&current_program_space->ebfd,
-						  sections);
+      current_program_space->add_target_sections
+	(current_program_space->ebfd.get (), sections);
 
       /* Tell display code (if any) about the changed file name.  */
       if (deprecated_exec_file_display_hook)
@@ -599,8 +599,8 @@ build_section_table (struct bfd *some_bfd)
    current set of target sections.  */
 
 void
-program_space::add_target_sections (const void *owner,
-				    const std::vector<target_section> &sections)
+program_space::add_target_sections
+  (target_section_owner owner, const std::vector<target_section> &sections)
 {
   if (!sections.empty ())
     {
@@ -643,7 +643,7 @@ program_space::add_target_sections (struct objfile *objfile)
 	continue;
 
       m_target_sections.emplace_back (osect->addr (), osect->endaddr (),
-				      osect->the_bfd_section, (void *) objfile);
+				      osect->the_bfd_section, objfile);
     }
 }
 
@@ -651,15 +651,15 @@ program_space::add_target_sections (struct objfile *objfile)
    OWNER must be the same value passed to add_target_sections.  */
 
 void
-program_space::remove_target_sections (const void *owner)
+program_space::remove_target_sections (target_section_owner owner)
 {
-  gdb_assert (owner != NULL);
+  gdb_assert (owner.v () != nullptr);
 
   auto it = std::remove_if (m_target_sections.begin (),
 			    m_target_sections.end (),
 			    [&] (target_section &sect)
 			    {
-			      return sect.owner == owner;
+			      return sect.owner.v () == owner.v ();
 			    });
   m_target_sections.erase (it, m_target_sections.end ());