gdbserver: turn target op 'qxfer_siginfo' into a method

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

	Turn process_stratum_target's qxfer_siginfo 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_siginfo'.
	* target.cc (process_target::qxfer_siginfo): Define.
	(process_target::supports_qxfer_siginfo): Define.

	Update the derived classes and callers below.

	* server.cc (handle_qxfer_siginfo): Update.
	(handle_query): Update.
	* linux-low.cc (linux_target_ops): Update.
	(linux_process_target::supports_qxfer_siginfo): Define.
	(linux_xfer_siginfo): Turn into ...
	(linux_process_target::qxfer_siginfo): ... 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_siginfo 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_siginfo'.
+	* target.cc (process_target::qxfer_siginfo): Define.
+	(process_target::supports_qxfer_siginfo): Define.
+
+	Update the derived classes and callers below.
+
+	* server.cc (handle_qxfer_siginfo): Update.
+	(handle_query): Update.
+	* linux-low.cc (linux_target_ops): Update.
+	(linux_process_target::supports_qxfer_siginfo): Define.
+	(linux_xfer_siginfo): Turn into ...
+	(linux_process_target::qxfer_siginfo): ... 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 qxfer_osdata op into a method of

gdbserver/linux-low.cc

@@ -6182,9 +6182,17 @@ siginfo_fixup (siginfo_t *siginfo, gdb_byte *inf_siginfo, int direction)
     }
 }
 
-static int
+bool
-linux_xfer_siginfo (const char *annex, unsigned char *readbuf,
+linux_process_target::supports_qxfer_siginfo ()
-		    unsigned const char *writebuf, CORE_ADDR offset, int len)
+{
+  return true;
+}
+
+int
+linux_process_target::qxfer_siginfo (const char *annex,
+				     unsigned char *readbuf,
+				     unsigned const char *writebuf,
+				     CORE_ADDR offset, int len)
 {
   int pid;
   siginfo_t siginfo;
@@ -7421,7 +7429,6 @@ linux_get_hwcap2 (int wordsize)
 static linux_process_target the_linux_target;
 
 static process_stratum_target linux_target_ops = {
-  linux_xfer_siginfo,
   linux_supports_non_stop,
   linux_async,
   linux_start_non_stop,

gdbserver/linux-low.h

@@ -351,6 +351,12 @@ public:
   int qxfer_osdata (const char *annex, unsigned char *readbuf,
 		    unsigned const char *writebuf,
 		    CORE_ADDR offset, int len) override;
+
+  bool supports_qxfer_siginfo () override;
+
+  int qxfer_siginfo (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_siginfo */
   NULL,  /* supports_non_stop */
   NULL,  /* async */
   NULL,  /* start_non_stop */

gdbserver/nto-low.cc

@@ -956,7 +956,6 @@ nto_sw_breakpoint_from_kind (int kind, int *size)
 static nto_process_target the_nto_target;
 
 static process_stratum_target nto_target_ops = {
-  NULL, /* xfer_siginfo */
   nto_supports_non_stop,
   NULL, /* async */
   NULL, /* start_non_stop */

gdbserver/server.cc

@@ -1600,13 +1600,13 @@ handle_qxfer_siginfo (const char *annex,
 		      gdb_byte *readbuf, const gdb_byte *writebuf,
 		      ULONGEST offset, LONGEST len)
 {
-  if (the_target->qxfer_siginfo == NULL)
+  if (!the_target->pt->supports_qxfer_siginfo ())
     return -2;
 
   if (annex[0] != '\0' || current_thread == NULL)
     return -1;
 
-  return (*the_target->qxfer_siginfo) (annex, readbuf, writebuf, offset, len);
+  return the_target->pt->qxfer_siginfo (annex, readbuf, writebuf, offset, len);
 }
 
 /* Handle qXfer:statictrace:read.  */
@@ -2377,7 +2377,7 @@ handle_query (char *own_buf, int packet_len, int *new_packet_len_p)
       if (the_target->pt->supports_read_auxv ())
 	strcat (own_buf, ";qXfer:auxv:read+");
 
-      if (the_target->qxfer_siginfo != NULL)
+      if (the_target->pt->supports_qxfer_siginfo ())
 	strcat (own_buf, ";qXfer:siginfo:read+;qXfer:siginfo:write+");
 
       if (the_target->read_loadmap != NULL)

gdbserver/target.cc

@@ -527,3 +527,17 @@ process_target::qxfer_osdata (const char *annex, unsigned char *readbuf,
 {
   gdb_assert_not_reached ("target op qxfer_osdata not supported");
 }
+
+bool
+process_target::supports_qxfer_siginfo ()
+{
+  return false;
+}
+
+int
+process_target::qxfer_siginfo (const char *annex, unsigned char *readbuf,
+			       unsigned const char *writebuf,
+			       CORE_ADDR offset, int len)
+{
+  gdb_assert_not_reached ("target op qxfer_siginfo not supported");
+}

gdbserver/target.h

@@ -70,11 +70,6 @@ class process_target;
    shared code.  */
 struct process_stratum_target
 {
-  /* Read/Write extra signal info.  */
-  int (*qxfer_siginfo) (const char *annex, unsigned char *readbuf,
-			unsigned const char *writebuf,
-			CORE_ADDR offset, int len);
-
   int (*supports_non_stop) (void);
 
   /* Enables async target events.  Returns the previous enable
@@ -482,6 +477,14 @@ public:
   virtual int qxfer_osdata (const char *annex, unsigned char *readbuf,
 			    unsigned const char *writebuf,
 			    CORE_ADDR offset, int len);
+
+  /* Return true if the qxfer_siginfo target op is supported.  */
+  virtual bool supports_qxfer_siginfo ();
+
+  /* Read/Write extra signal info.  */
+  virtual int qxfer_siginfo (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

@@ -1793,11 +1793,19 @@ win32_process_target::hostio_last_error (char *buf)
 }
 #endif
 
+bool
+win32_process_target::supports_qxfer_siginfo ()
+{
+  return true;
+}
+
 /* Write Windows signal info.  */
 
-static int
+int
-win32_xfer_siginfo (const char *annex, unsigned char *readbuf,
+win32_process_target::qxfer_siginfo (const char *annex,
-		    unsigned const char *writebuf, CORE_ADDR offset, int len)
+				     unsigned char *readbuf,
+				     unsigned const char *writebuf,
+				     CORE_ADDR offset, int len)
 {
   if (siginfo_er.ExceptionCode == 0)
     return -1;
@@ -1844,7 +1852,6 @@ win32_sw_breakpoint_from_kind (int kind, int *size)
 static win32_process_target the_win32_target;
 
 static process_stratum_target win32_target_ops = {
-  win32_xfer_siginfo,
   NULL, /* supports_non_stop */
   NULL, /* async */
   NULL, /* start_non_stop */

gdbserver/win32-low.h

@@ -156,6 +156,12 @@ public:
 #ifdef _WIN32_WCE
   void hostio_last_error (char *buf) override;
 #endif
+
+  bool supports_qxfer_siginfo () override;
+
+  int qxfer_siginfo (const char *annex, unsigned char *readbuf,
+		     unsigned const char *writebuf,
+		     CORE_ADDR offset, int len) override;
 };
 
 /* Retrieve the context for this thread, if not already retrieved.  */