gdbserver: turn target op 'qxfer_libraries_svr4' into a method

gdbserver/ChangeLog:
2020-02-20  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>

	Turn process_stratum_target's qxfer_libraries_svr4 op into a
	method of process_target.

	* target.h (struct process_stratum_target): Remove the target op.
	(class process_target): Add the target op.  Also add
	'supports_qxfer_libraries_svr4'.
	* target.cc (process_target::qxfer_libraries_svr4): Define.
	(process_target::supports_qxfer_libraries_svr4): Define.

	Update the derived classes and callers below.

	* server.cc (handle_qxfer_libraries_svr4): Update.
	(handle_query): Update.
	* linux-low.cc (linux_target_ops): Update.
	(linux_process_target::supports_qxfer_libraries_svr4): Define.
	(linux_qxfer_libraries_svr4): Turn into ...
	(linux_process_target::qxfer_libraries_svr4): ... this.
	* linux-low.h (class linux_process_target): Update.
	* lynx-low.cc (lynx_target_ops): Update.
	* nto-low.cc (nto_target_ops): Update.
	* win32-low.cc (win32_target_ops): Update.

gdbserver/ChangeLog

@@ -1,3 +1,27 @@
+2020-02-20  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>
+
+	Turn process_stratum_target's qxfer_libraries_svr4 op into a
+	method of process_target.
+
+	* target.h (struct process_stratum_target): Remove the target op.
+	(class process_target): Add the target op.  Also add
+	'supports_qxfer_libraries_svr4'.
+	* target.cc (process_target::qxfer_libraries_svr4): Define.
+	(process_target::supports_qxfer_libraries_svr4): Define.
+
+	Update the derived classes and callers below.
+
+	* server.cc (handle_qxfer_libraries_svr4): Update.
+	(handle_query): Update.
+	* linux-low.cc (linux_target_ops): Update.
+	(linux_process_target::supports_qxfer_libraries_svr4): Define.
+	(linux_qxfer_libraries_svr4): Turn into ...
+	(linux_process_target::qxfer_libraries_svr4): ... this.
+	* linux-low.h (class linux_process_target): Update.
+	* lynx-low.cc (lynx_target_ops): Update.
+	* nto-low.cc (nto_target_ops): Update.
+	* win32-low.cc (win32_target_ops): Update.
+
 2020-02-20  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>
 
 	Turn process_stratum_target's supports_disable_randomization op

gdbserver/linux-low.cc

@@ -6931,6 +6931,12 @@ read_one_ptr (CORE_ADDR memaddr, CORE_ADDR *ptr, int ptr_size)
   return ret;
 }
 
+bool
+linux_process_target::supports_qxfer_libraries_svr4 ()
+{
+  return true;
+}
+
 struct link_map_offsets
   {
     /* Offset and size of r_debug.r_version.  */
@@ -6957,10 +6963,11 @@ struct link_map_offsets
 
 /* Construct qXfer:libraries-svr4:read reply.  */
 
-static int
+int
-linux_qxfer_libraries_svr4 (const char *annex, unsigned char *readbuf,
+linux_process_target::qxfer_libraries_svr4 (const char *annex,
-			    unsigned const char *writebuf,
+					    unsigned char *readbuf,
-			    CORE_ADDR offset, int len)
+					    unsigned const char *writebuf,
+					    CORE_ADDR offset, int len)
 {
   struct process_info_private *const priv = current_process ()->priv;
   char filename[PATH_MAX];
@@ -7456,7 +7463,6 @@ linux_get_hwcap2 (int wordsize)
 static linux_process_target the_linux_target;
 
 static process_stratum_target linux_target_ops = {
-  linux_qxfer_libraries_svr4,
   linux_supports_agent,
 #ifdef HAVE_LINUX_BTRACE
   linux_enable_btrace,

gdbserver/linux-low.h

@@ -424,6 +424,13 @@ public:
   struct emit_ops *emit_ops () override;
 
   bool supports_disable_randomization () override;
+
+  bool supports_qxfer_libraries_svr4 () override;
+
+  int qxfer_libraries_svr4 (const char *annex,
+			    unsigned char *readbuf,
+			    unsigned const char *writebuf,
+			    CORE_ADDR offset, int len) override;
 };
 
 #define get_thread_lwp(thr) ((struct lwp_info *) (thread_target_data (thr)))

gdbserver/lynx-low.cc

@@ -735,7 +735,6 @@ static lynx_process_target the_lynx_target;
 /* The LynxOS target_ops vector.  */
 
 static process_stratum_target lynx_target_ops = {
-  NULL,  /* qxfer_libraries_svr4 */
   NULL,  /* support_agent */
   NULL,  /* enable_btrace */
   NULL,  /* disable_btrace */

gdbserver/nto-low.cc

@@ -947,7 +947,6 @@ nto_sw_breakpoint_from_kind (int kind, int *size)
 static nto_process_target the_nto_target;
 
 static process_stratum_target nto_target_ops = {
-  NULL, /* qxfer_libraries_svr4 */
   NULL, /* support_agent */
   NULL, /* enable_btrace */
   NULL, /* disable_btrace */

gdbserver/server.cc

@@ -1574,10 +1574,12 @@ handle_qxfer_libraries_svr4 (const char *annex,
   if (writebuf != NULL)
     return -2;
 
-  if (current_thread == NULL || the_target->qxfer_libraries_svr4 == NULL)
+  if (current_thread == NULL
+      || !the_target->pt->supports_qxfer_libraries_svr4 ())
     return -1;
 
-  return the_target->qxfer_libraries_svr4 (annex, readbuf, writebuf, offset, len);
+  return the_target->pt->qxfer_libraries_svr4 (annex, readbuf, writebuf,
+					       offset, len);
 }
 
 /* Handle qXfer:osadata:read.  */
@@ -2364,7 +2366,7 @@ handle_query (char *own_buf, int packet_len, int *new_packet_len_p)
       if (target_supports_catch_syscall ())
 	strcat (own_buf, ";QCatchSyscalls+");
 
-      if (the_target->qxfer_libraries_svr4 != NULL)
+      if (the_target->pt->supports_qxfer_libraries_svr4 ())
 	strcat (own_buf, ";qXfer:libraries-svr4:read+"
 		";augmented-libraries-svr4-read+");
       else

gdbserver/target.cc

@@ -705,3 +705,18 @@ process_target::supports_disable_randomization ()
 {
   return false;
 }
+
+bool
+process_target::supports_qxfer_libraries_svr4 ()
+{
+  return false;
+}
+
+int
+process_target::qxfer_libraries_svr4 (const char *annex,
+				      unsigned char *readbuf,
+				      unsigned const char *writebuf,
+				      CORE_ADDR offset, int len)
+{
+  gdb_assert_not_reached ("target op qxfer_libraries_svr4 not supported");
+}

gdbserver/target.h

@@ -70,11 +70,6 @@ class process_target;
    shared code.  */
 struct process_stratum_target
 {
-  /* Read solib info on SVR4 platforms.  */
-  int (*qxfer_libraries_svr4) (const char *annex, unsigned char *readbuf,
-			       unsigned const char *writebuf,
-			       CORE_ADDR offset, int len);
-
   /* Return true if target supports debugging agent.  */
   int (*supports_agent) (void);
 
@@ -493,6 +488,15 @@ public:
 
   /* Returns true if the target supports disabling randomization.  */
   virtual bool supports_disable_randomization ();
+
+  /* Return true if the qxfer_libraries_svr4 op is supported.  */
+  virtual bool supports_qxfer_libraries_svr4 ();
+
+  /* Read solib info on SVR4 platforms.  */
+  virtual int qxfer_libraries_svr4 (const char *annex,
+				    unsigned char *readbuf,
+				    unsigned const char *writebuf,
+				    CORE_ADDR offset, int len);
 };
 
 extern process_stratum_target *the_target;

gdbserver/win32-low.cc

@@ -1858,7 +1858,6 @@ win32_sw_breakpoint_from_kind (int kind, int *size)
 static win32_process_target the_win32_target;
 
 static process_stratum_target win32_target_ops = {
-  NULL, /* qxfer_libraries_svr4 */
   NULL, /* support_agent */
   NULL, /* enable_btrace */
   NULL, /* disable_btrace */