Move gdbserver to top level

This patch moves gdbserver to the top level.

This patch is as close to a pure move as possible -- gdbserver still
builds its own variant of gnulib and gdbsupport.  Changing this will
be done in a separate patch.

[v2] Note that, per Simon's review comment, this patch changes the
tree so that gdbserver is not built for or1k or score.  This makes
sense, because there is apparently not actually a gdbserver port here.

[v3] This version of the patch also splits out some configury into a
new file, gdbserver/configure.host, so that the top-level configure
script can simply rely on it in order to decide whether gdbserver
should be built.

[v4] This version adds documentation and removes some unnecessary
top-level dependencies.

[v5] Update docs to mention "make all-gdbserver" and change how
top-level configure decides whether to build gdbserver, switching to a
single, shared script.

Tested by the buildbot.

ChangeLog
2020-02-07  Tom Tromey  <tom@tromey.com>
	    Pedro Alves  <palves@redhat.com>

	* src-release.sh (GDB_SUPPORT_DIRS): Add gdbserver.
	* gdbserver: New directory, moved from gdb/gdbserver.
	* configure.ac (host_tools): Add gdbserver.
	Only build gdbserver on certain systems.
	* Makefile.in, configure: Rebuild.
	* Makefile.def (host_modules, dependencies): Add gdbserver.
	* MAINTAINERS: Add gdbserver.

gdb/ChangeLog
2020-02-07  Tom Tromey  <tom@tromey.com>

	* README: Update gdbserver documentation.
	* gdbserver: Move to top level.
	* configure.tgt (build_gdbserver): Remove.
	* configure.ac: Remove --enable-gdbserver.
	* configure: Rebuild.
	* Makefile.in (distclean): Don't mention gdbserver.

Change-Id: I826b7565b54604711dc7a11edea0499cd51ff39e

1 files changed, 195 insertions, 0 deletions

diff --git a/gdbserver/tracepoint.h b/gdbserver/tracepoint.h
new file mode 100644
index 0000000..030b2a9
--- /dev/null
+++ b/gdbserver/tracepoint.h
@@ -0,0 +1,195 @@
+/* Tracepoint code for remote server for GDB.
+   Copyright (C) 1993-2020 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef GDBSERVER_TRACEPOINT_H
+#define GDBSERVER_TRACEPOINT_H
+
+/* Size for a small buffer to report problems from the in-process
+   agent back to GDBserver.  */
+#define IPA_BUFSIZ 100
+
+void initialize_tracepoint (void);
+
+#if defined(__GNUC__)
+# define ATTR_USED __attribute__((used))
+# define ATTR_NOINLINE __attribute__((noinline))
+#else
+# define ATTR_USED
+# define ATTR_NOINLINE
+#endif
+
+/* How to make symbol public/exported.  */
+
+#if defined _WIN32 || defined __CYGWIN__
+# define EXPORTED_SYMBOL __declspec (dllexport)
+#else
+# if __GNUC__ >= 4
+#  define EXPORTED_SYMBOL __attribute__ ((visibility ("default")))
+# else
+#  define EXPORTED_SYMBOL
+# endif
+#endif
+
+/* Use these to make sure the functions and variables the IPA needs to
+   export (symbols GDBserver needs to query GDB about) are visible and
+   have C linkage.
+
+   Tag exported functions with IP_AGENT_EXPORT_FUNC, tag the
+   definitions of exported variables with IP_AGENT_EXPORT_VAR, and
+   variable declarations with IP_AGENT_EXPORT_VAR_DECL.  Variables
+   must also be exported with C linkage.  As we can't both use extern
+   "C" and initialize a variable in the same statement, variables that
+   don't have a separate declaration must use
+   EXTERN_C_PUSH/EXTERN_C_POP around their definition.  */
+
+#ifdef IN_PROCESS_AGENT
+# define IP_AGENT_EXPORT_FUNC EXTERN_C EXPORTED_SYMBOL ATTR_NOINLINE ATTR_USED
+# define IP_AGENT_EXPORT_VAR EXPORTED_SYMBOL ATTR_USED
+# define IP_AGENT_EXPORT_VAR_DECL EXTERN_C EXPORTED_SYMBOL
+#else
+# define IP_AGENT_EXPORT_FUNC static
+# define IP_AGENT_EXPORT_VAR
+# define IP_AGENT_EXPORT_VAR_DECL extern
+#endif
+
+IP_AGENT_EXPORT_VAR_DECL int tracing;
+
+extern int disconnected_tracing;
+
+void tracepoint_look_up_symbols (void);
+
+void stop_tracing (void);
+
+int handle_tracepoint_general_set (char *own_buf);
+int handle_tracepoint_query (char *own_buf);
+
+int tracepoint_finished_step (struct thread_info *tinfo, CORE_ADDR stop_pc);
+int tracepoint_was_hit (struct thread_info *tinfo, CORE_ADDR stop_pc);
+
+void release_while_stepping_state_list (struct thread_info *tinfo);
+
+int in_readonly_region (CORE_ADDR addr, ULONGEST length);
+int traceframe_read_mem (int tfnum, CORE_ADDR addr,
+			 unsigned char *buf, ULONGEST length,
+			 ULONGEST *nbytes);
+int fetch_traceframe_registers (int tfnum,
+				struct regcache *regcache,
+				int regnum);
+
+int traceframe_read_sdata (int tfnum, ULONGEST offset,
+			   unsigned char *buf, ULONGEST length,
+			   ULONGEST *nbytes);
+
+int traceframe_read_info (int tfnum, struct buffer *buffer);
+
+/* If a thread is determined to be collecting a fast tracepoint, this
+   structure holds the collect status.  */
+
+struct fast_tpoint_collect_status
+{
+  /* The tracepoint that is presently being collected.  */
+  int tpoint_num;
+  CORE_ADDR tpoint_addr;
+
+  /* The address range in the jump pad of where the original
+     instruction the tracepoint jump was inserted was relocated
+     to.  */
+  CORE_ADDR adjusted_insn_addr;
+  CORE_ADDR adjusted_insn_addr_end;
+};
+
+/* The possible states a thread can be in, related to the collection of fast
+   tracepoint.  */
+
+enum class fast_tpoint_collect_result
+{
+  /* Not collecting a fast tracepoint.  */
+  not_collecting,
+
+  /* In the jump pad, but before the relocated instruction.  */
+  before_insn,
+
+  /* In the jump pad, but at (or after) the relocated instruction.  */
+  at_insn,
+};
+
+fast_tpoint_collect_result fast_tracepoint_collecting
+  (CORE_ADDR thread_area, CORE_ADDR stop_pc,
+   struct fast_tpoint_collect_status *status);
+
+void force_unlock_trace_buffer (void);
+
+int handle_tracepoint_bkpts (struct thread_info *tinfo, CORE_ADDR stop_pc);
+
+#ifdef IN_PROCESS_AGENT
+void initialize_low_tracepoint (void);
+const struct target_desc *get_ipa_tdesc (int idx);
+void supply_fast_tracepoint_registers (struct regcache *regcache,
+				       const unsigned char *regs);
+void supply_static_tracepoint_registers (struct regcache *regcache,
+					 const unsigned char *regs,
+					 CORE_ADDR pc);
+void set_trampoline_buffer_space (CORE_ADDR begin, CORE_ADDR end,
+				  char *errmsg);
+void *alloc_jump_pad_buffer (size_t size);
+#ifndef HAVE_GETAUXVAL
+unsigned long getauxval (unsigned long type);
+#endif
+#else
+void stop_tracing (void);
+
+int claim_trampoline_space (ULONGEST used, CORE_ADDR *trampoline);
+int have_fast_tracepoint_trampoline_buffer (char *msgbuf);
+void gdb_agent_about_to_close (int pid);
+#endif
+
+struct traceframe;
+struct eval_agent_expr_context;
+
+/* Do memory copies for bytecodes.  */
+/* Do the recording of memory blocks for actions and bytecodes.  */
+
+int agent_mem_read (struct eval_agent_expr_context *ctx,
+		    unsigned char *to, CORE_ADDR from,
+		    ULONGEST len);
+
+LONGEST agent_get_trace_state_variable_value (int num);
+void agent_set_trace_state_variable_value (int num, LONGEST val);
+
+/* Record the value of a trace state variable.  */
+
+int agent_tsv_read (struct eval_agent_expr_context *ctx, int n);
+int agent_mem_read_string (struct eval_agent_expr_context *ctx,
+			   unsigned char *to,
+			   CORE_ADDR from,
+			   ULONGEST len);
+
+/* The prototype the get_raw_reg function in the IPA.  Each arch's
+   bytecode compiler emits calls to this function.  */
+ULONGEST get_raw_reg (const unsigned char *raw_regs, int regnum);
+
+/* Returns the address of the get_raw_reg function in the IPA.  */
+CORE_ADDR get_raw_reg_func_addr (void);
+/* Returns the address of the get_trace_state_variable_value
+   function in the IPA.  */
+CORE_ADDR get_get_tsv_func_addr (void);
+/* Returns the address of the set_trace_state_variable_value
+   function in the IPA.  */
+CORE_ADDR get_set_tsv_func_addr (void);
+
+#endif /* GDBSERVER_TRACEPOINT_H */