gdb: Delay releasing target_desc_up in more cases

After commit:

  commit 51a948fdf0e14fb69ab9e0c79ae8b2415801f9a3
  Date:   Mon Jul 20 14:18:04 2020 +0100

      gdb: Have allocate_target_description return a unique_ptr

There were a few places where we could (should?) have delayed
releasing the target_desc_up until a little later.  This commit
catches these cases.

In the case of ARC, the target_desc_up is now exposed right out to
gdbserver, which means making a small change there too.

There should be no user visible changes after this commit.

gdb/ChangeLog:

	* arch/aarch32.c (aarch32_create_target_description): Release the
	target_desc_up as late as possible.
	* arch/aarch64.c (aarch64_create_target_description): Likewise.
	* arch/amd64.c (amd64_create_target_description): Likewise.
	* arch/arc.c (arc_create_target_description): Return a
	target_desc_up, don't release it.
	* arch/arc.h (arc_create_target_description): Update declaration.
	(arc_lookup_target_description): Move target_desc_up into the
	cache, and return a borrowed pointer.
	* arch/arm.c (arm_create_target_description): Release the
	target_desc_up as late as possible.
	* arch/i386.c (i386_create_target_description): Likewise.
	* arch/riscv.h (riscv_create_target_description): Update
	declaration to match definition.
	* arch/tic6x.c (tic6x_create_target_description): Release the
	target_desc_up as late as possible.

gdbserver/ChangeLog:

	* linux-arc-low.cc (arc_linux_read_description): Release the
	unique_ptr returned from arc_create_target_description.

1 files changed, 14 insertions, 11 deletions

diff --git a/gdb/arch/arc.c b/gdb/arch/arc.c
index dff4575..abed8a6 100644
--- a/gdb/arch/arc.c
+++ b/gdb/arch/arc.c
@@ -34,11 +34,11 @@
 #define STATIC_IN_GDB
 #endif
 
-STATIC_IN_GDB target_desc *
+STATIC_IN_GDB target_desc_up
 arc_create_target_description (const struct arc_arch_features &features)
 {
   /* Create a new target description.  */
-  target_desc *tdesc = allocate_target_description ().release ();
+  target_desc_up tdesc = allocate_target_description ();
 
 #ifndef IN_PROCESS_AGENT
   std::string arch_name;
@@ -57,7 +57,7 @@ arc_create_target_description (const struct arc_arch_features &features)
       gdb_assert_not_reached (msg.c_str ());
     }
 
-  set_tdesc_architecture (tdesc, arch_name.c_str ());
+  set_tdesc_architecture (tdesc.get (), arch_name.c_str ());
 #endif
 
   long regnum = 0;
@@ -65,12 +65,12 @@ arc_create_target_description (const struct arc_arch_features &features)
   switch (features.isa)
     {
     case ARC_ISA_ARCV1:
-      regnum = create_feature_arc_v1_core (tdesc, regnum);
-      regnum = create_feature_arc_v1_aux (tdesc, regnum);
+      regnum = create_feature_arc_v1_core (tdesc.get (), regnum);
+      regnum = create_feature_arc_v1_aux (tdesc.get (), regnum);
       break;
     case ARC_ISA_ARCV2:
-      regnum = create_feature_arc_v2_core (tdesc, regnum);
-      regnum = create_feature_arc_v2_aux (tdesc, regnum);
+      regnum = create_feature_arc_v2_core (tdesc.get (), regnum);
+      regnum = create_feature_arc_v2_aux (tdesc.get (), regnum);
       break;
     default:
       std::string msg = string_printf
@@ -111,12 +111,15 @@ arc_lookup_target_description (const struct arc_arch_features &features)
   if (it != arc_tdesc_cache.end ())
     return it->second.get ();
 
-  target_desc *tdesc = arc_create_target_description (features);
+  target_desc_up tdesc = arc_create_target_description (features);
 
-  /* Add the newly created target description to the repertoire.  */
-  arc_tdesc_cache.emplace (features, tdesc);
 
-  return tdesc;
+  /* Add to the cache, and return a pointer borrowed from the
+     target_desc_up.  This is safe as the cache (and the pointers
+     contained within it) are not deleted until GDB exits.  */
+  target_desc *ptr = tdesc.get ();
+  arc_tdesc_cache.emplace (features, std::move (tdesc));
+  return ptr;
 }
 
 #endif /* !GDBSERVER */