Introduce gdb_dlhandle_up

This introduces gdb_dlhandle_up, a unique_ptr that can close a
dlopen'd library.  All the functions working with dlopen handles are
updated to use this new type.

I did not try to build this on Windows.

gdb/ChangeLog
2017-04-12  Tom Tromey  <tom@tromey.com>

	* jit.c (struct jit_reader): Declare separately.  Add constructor
	and destructor.  Change type of "handle".
	(loaded_jit_reader): Define separately.
	(jit_reader_load): Update.  New "new".
	(jit_reader_unload_command): Use "delete".
	* gdb-dlfcn.h (struct dlclose_deleter): New.
	(gdb_dlhandle_up): New typedef.
	(gdb_dlopen, gdb_dlsym): Update types.
	(gdb_dlclose): Remove.
	* gdb-dlfcn.c (gdb_dlopen): Return a gdb_dlhandle_up.
	(gdb_dlsym): Change type of "handle".
	(make_cleanup_dlclose): Remove.
	(dlclose_deleter::operator()): Rename from gdb_dlclose.
	* compile/compile-c-support.c (load_libcc): Update.

1 files changed, 13 insertions, 11 deletions

diff --git a/gdb/gdb-dlfcn.h b/gdb/gdb-dlfcn.h
index 31709a9..021f759 100644
--- a/gdb/gdb-dlfcn.h
+++ b/gdb/gdb-dlfcn.h
@@ -20,26 +20,28 @@
 #ifndef GDB_DLFCN_H
 #define GDB_DLFCN_H
 
+/* A deleter that closes an open dynamic library.  */
+
+struct dlclose_deleter
+{
+  void operator() (void *handle) const;
+};
+
+/* A unique pointer that points to a dynamic library.  */
+
+typedef std::unique_ptr<void, dlclose_deleter> gdb_dlhandle_up;
+
 /* Load the dynamic library file named FILENAME, and return a handle
    for that dynamic library.  Return NULL if the loading fails for any
    reason.  */
 
-void *gdb_dlopen (const char *filename);
+gdb_dlhandle_up gdb_dlopen (const char *filename);
 
 /* Return the address of the symbol named SYMBOL inside the shared
    library whose handle is HANDLE.  Return NULL when the symbol could
    not be found.  */
 
-void *gdb_dlsym (void *handle, const char *symbol);
-
-/* Install a cleanup routine which closes the handle HANDLE.  */
-
-struct cleanup *make_cleanup_dlclose (void *handle);
-
-/* Cleanup the shared object pointed to by HANDLE. Return 0 on success
-   and nonzero on failure.  */
-
-int gdb_dlclose (void *handle);
+void *gdb_dlsym (const gdb_dlhandle_up &handle, const char *symbol);
 
 /* Return non-zero if the dynamic library functions are available on
    this platform.  */