gdbserver/linux-low: turn 'supports_software_single_step' and 'get_next_pcs' into methods

gdbserver/ChangeLog:
2020-04-02  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>

	Remove the 'supports_software_single_step' linux target op and let
	the concrete linux target define it by overriding the op in
	process_stratum_target.
	Turn the 'get_next_pcs' linux target op into a method of
	linux_process_target.

	* linux-low.h (struct linux_target_ops): Remove the ops.
	(class linux_process_target) <supports_software_single_step>:
	Remove.
	<low_get_next_pcs>: Declare.
	* linux-low.cc (can_software_single_step): Remove.
	(linux_process_target::low_get_next_pcs): Define.
	(linux_process_target::supports_software_single_step): Remove.

	Update the callers below.

	(linux_process_target::handle_extended_wait)
	(linux_process_target::wait_1)
	(linux_process_target::install_software_single_step_breakpoints)
	(linux_process_target::single_step)
	(linux_process_target::thread_needs_step_over)
	(linux_process_target::proceed_one_lwp)
	(linux_process_target::supports_range_stepping)

	* linux-x86-low.cc (the_low_target): Remove the op field.
	* linux-aarch64-low.cc (the_low_target): Ditto.
	* linux-bfin-low.cc (the_low_target): Ditto.
	* linux-cris-low.cc (the_low_target): Ditto.
	* linux-crisv32-low.cc (the_low_target): Ditto.
	* linux-m32r-low.cc (the_low_target): Ditto.
	* linux-m68k-low.cc (the_low_target): Ditto.
	* linux-mips-low.cc (the_low_target): Ditto.
	* linux-nios2-low.cc (the_low_target): Ditto.
	* linux-ppc-low.cc (the_low_target): Ditto.
	* linux-riscv-low.cc (the_low_target): Ditto.
	* linux-s390-low.cc (the_low_target): Ditto.
	* linux-sh-low.cc (the_low_target): Ditto.
	* linux-sparc-low.cc (the_low_target): Ditto.
	* linux-tic6x-low.cc (the_low_target): Ditto.
	* linux-tile-low.cc (the_low_target): Ditto.
	* linux-xtensa-low.cc (the_low_target): Ditto.
	* linux-arm-low.cc (class arm_target) <low_get_next_pcs>
	<supports_software_single_step>: Declare.
	(arm_target::supports_software_single_step): Define.
	(arm_gdbserver_get_next_pcs): Turn into...
	(arm_target::low_get_next_pcs): ...this.
	(the_low_target): Remove the op field.

21 files changed, 84 insertions, 50 deletions

diff --git a/gdbserver/ChangeLog b/gdbserver/ChangeLog
index 77c766d..f9a3df2 100644
--- a/gdbserver/ChangeLog
+++ b/gdbserver/ChangeLog
@@ -1,5 +1,55 @@
 2020-04-02  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>
 
+	Remove the 'supports_software_single_step' linux target op and let
+	the concrete linux target define it by overriding the op in
+	process_stratum_target.
+	Turn the 'get_next_pcs' linux target op into a method of
+	linux_process_target.
+
+	* linux-low.h (struct linux_target_ops): Remove the ops.
+	(class linux_process_target) <supports_software_single_step>:
+	Remove.
+	<low_get_next_pcs>: Declare.
+	* linux-low.cc (can_software_single_step): Remove.
+	(linux_process_target::low_get_next_pcs): Define.
+	(linux_process_target::supports_software_single_step): Remove.
+
+	Update the callers below.
+
+	(linux_process_target::handle_extended_wait)
+	(linux_process_target::wait_1)
+	(linux_process_target::install_software_single_step_breakpoints)
+	(linux_process_target::single_step)
+	(linux_process_target::thread_needs_step_over)
+	(linux_process_target::proceed_one_lwp)
+	(linux_process_target::supports_range_stepping)
+
+	* linux-x86-low.cc (the_low_target): Remove the op field.
+	* linux-aarch64-low.cc (the_low_target): Ditto.
+	* linux-bfin-low.cc (the_low_target): Ditto.
+	* linux-cris-low.cc (the_low_target): Ditto.
+	* linux-crisv32-low.cc (the_low_target): Ditto.
+	* linux-m32r-low.cc (the_low_target): Ditto.
+	* linux-m68k-low.cc (the_low_target): Ditto.
+	* linux-mips-low.cc (the_low_target): Ditto.
+	* linux-nios2-low.cc (the_low_target): Ditto.
+	* linux-ppc-low.cc (the_low_target): Ditto.
+	* linux-riscv-low.cc (the_low_target): Ditto.
+	* linux-s390-low.cc (the_low_target): Ditto.
+	* linux-sh-low.cc (the_low_target): Ditto.
+	* linux-sparc-low.cc (the_low_target): Ditto.
+	* linux-tic6x-low.cc (the_low_target): Ditto.
+	* linux-tile-low.cc (the_low_target): Ditto.
+	* linux-xtensa-low.cc (the_low_target): Ditto.
+	* linux-arm-low.cc (class arm_target) <low_get_next_pcs>
+	<supports_software_single_step>: Declare.
+	(arm_target::supports_software_single_step): Define.
+	(arm_gdbserver_get_next_pcs): Turn into...
+	(arm_target::low_get_next_pcs): ...this.
+	(the_low_target): Remove the op field.
+
+2020-04-02  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>
+
 	Remove the 'sw_breakpoint_from_kind' linux target op, and let
 	the concrete linux target define it by overriding the op
 	in process_stratum_target.
diff --git a/gdbserver/linux-aarch64-low.cc b/gdbserver/linux-aarch64-low.cc
index 23c9c3e..11c3296 100644
--- a/gdbserver/linux-aarch64-low.cc
+++ b/gdbserver/linux-aarch64-low.cc
@@ -3103,7 +3103,6 @@ aarch64_supports_hardware_single_step (void)
 
 struct linux_target_ops the_low_target =
 {
-  NULL, /* get_next_pcs */
   0,    /* decr_pc_after_break */
   aarch64_breakpoint_at,
   aarch64_supports_z_point_type,
diff --git a/gdbserver/linux-arm-low.cc b/gdbserver/linux-arm-low.cc
index aab2c42..bd42feba 100644
--- a/gdbserver/linux-arm-low.cc
+++ b/gdbserver/linux-arm-low.cc
@@ -68,6 +68,8 @@ public:
 
   const gdb_byte *sw_breakpoint_from_kind (int kind, int *size) override;
 
+  bool supports_software_single_step () override;
+
 protected:
 
   void low_arch_setup () override;
@@ -81,6 +83,8 @@ protected:
   CORE_ADDR low_get_pc (regcache *regcache) override;
 
   void low_set_pc (regcache *regcache, CORE_ADDR newpc) override;
+
+  std::vector<CORE_ADDR> low_get_next_pcs (regcache *regcache) override;
 };
 
 /* The singleton target ops object.  */
@@ -968,10 +972,16 @@ arm_target::low_arch_setup ()
     have_ptrace_getregset = 0;
 }
 
+bool
+arm_target::supports_software_single_step ()
+{
+  return true;
+}
+
 /* Fetch the next possible PCs after the current instruction executes.  */
 
-static std::vector<CORE_ADDR>
-arm_gdbserver_get_next_pcs (struct regcache *regcache)
+std::vector<CORE_ADDR>
+arm_target::low_get_next_pcs (regcache *regcache)
 {
   struct arm_get_next_pcs next_pcs_ctx;
 
@@ -1075,7 +1085,6 @@ arm_target::get_regs_info ()
 }
 
 struct linux_target_ops the_low_target = {
-  arm_gdbserver_get_next_pcs,
   0,
   arm_breakpoint_at,
   arm_supports_z_point_type,
diff --git a/gdbserver/linux-bfin-low.cc b/gdbserver/linux-bfin-low.cc
index c798c93..17948ed 100644
--- a/gdbserver/linux-bfin-low.cc
+++ b/gdbserver/linux-bfin-low.cc
@@ -161,7 +161,6 @@ bfin_target::get_regs_info ()
 }
 
 struct linux_target_ops the_low_target = {
-  NULL, /* get_next_pcs */
   2,
   bfin_breakpoint_at,
   NULL, /* supports_z_point_type */
diff --git a/gdbserver/linux-cris-low.cc b/gdbserver/linux-cris-low.cc
index a22ec33..99060de 100644
--- a/gdbserver/linux-cris-low.cc
+++ b/gdbserver/linux-cris-low.cc
@@ -158,7 +158,6 @@ cris_target::get_regs_info ()
 }
 
 struct linux_target_ops the_low_target = {
-  NULL, /* get_next_pcs */
   0,
   cris_breakpoint_at,
 };
diff --git a/gdbserver/linux-crisv32-low.cc b/gdbserver/linux-crisv32-low.cc
index 965f186..c75e428 100644
--- a/gdbserver/linux-crisv32-low.cc
+++ b/gdbserver/linux-crisv32-low.cc
@@ -455,7 +455,6 @@ crisv32_target::get_regs_info ()
 }
 
 struct linux_target_ops the_low_target = {
-  NULL, /* get_next_pcs */
   0,
   cris_breakpoint_at,
   cris_supports_z_point_type,
diff --git a/gdbserver/linux-low.cc b/gdbserver/linux-low.cc
index 14a4dbf..8eca077 100644
--- a/gdbserver/linux-low.cc
+++ b/gdbserver/linux-low.cc
@@ -292,15 +292,6 @@ can_hardware_single_step (void)
     return 0;
 }
 
-/* True if the low target can software single-step.  Such targets
-   implement the GET_NEXT_PCS callback.  */
-
-static int
-can_software_single_step (void)
-{
-  return (the_low_target.get_next_pcs != NULL);
-}
-
 bool
 linux_process_target::low_supports_breakpoints ()
 {
@@ -319,6 +310,13 @@ linux_process_target::low_set_pc (regcache *regcache, CORE_ADDR newpc)
   gdb_assert_not_reached ("linux target op low_set_pc is not implemented");
 }
 
+std::vector<CORE_ADDR>
+linux_process_target::low_get_next_pcs (regcache *regcache)
+{
+  gdb_assert_not_reached ("linux target op low_get_next_pcs is not "
+			  "implemented");
+}
+
 /* Returns true if this target can support fast tracepoints.  This
    does not mean that the in-process agent has been loaded in the
    inferior.  */
@@ -551,7 +549,7 @@ linux_process_target::handle_extended_wait (lwp_info **orig_event_lwp,
 	  child_proc->attached = parent_proc->attached;
 
 	  if (event_lwp->bp_reinsert != 0
-	      && can_software_single_step ()
+	      && supports_software_single_step ()
 	      && event == PTRACE_EVENT_VFORK)
 	    {
 	      /* If we leave single-step breakpoints there, child will
@@ -596,7 +594,7 @@ linux_process_target::handle_extended_wait (lwp_info **orig_event_lwp,
 	     In case of vfork, we'll reinsert them back once vforked
 	     child is done.  */
 	  if (event_lwp->bp_reinsert != 0
-	      && can_software_single_step ())
+	      && supports_software_single_step ())
 	    {
 	      /* The child process is forked and stopped, so it is safe
 		 to access its memory without stopping all other threads
@@ -660,7 +658,7 @@ linux_process_target::handle_extended_wait (lwp_info **orig_event_lwp,
     {
       event_lwp->waitstatus.kind = TARGET_WAITKIND_VFORK_DONE;
 
-      if (event_lwp->bp_reinsert != 0 && can_software_single_step ())
+      if (event_lwp->bp_reinsert != 0 && supports_software_single_step ())
 	{
 	  reinsert_single_step_breakpoints (event_thr);
 
@@ -3508,7 +3506,7 @@ linux_process_target::wait_1 (ptid_t ptid, target_waitstatus *ourstatus,
 	  /* Remove the single-step breakpoints if any.  Note that
 	     there isn't single-step breakpoint if we finished stepping
 	     over.  */
-	  if (can_software_single_step ()
+	  if (supports_software_single_step ()
 	      && has_single_step_breakpoints (current_thread))
 	    {
 	      stop_all_lwps (0, event_child);
@@ -3555,7 +3553,7 @@ linux_process_target::wait_1 (ptid_t ptid, target_waitstatus *ourstatus,
   /* Alright, we're going to report a stop.  */
 
   /* Remove single-step breakpoints.  */
-  if (can_software_single_step ())
+  if (supports_software_single_step ())
     {
       /* Remove single-step breakpoints or not.  It it is true, stop all
 	 lwps, so that other threads won't hit the breakpoint in the
@@ -4116,7 +4114,7 @@ linux_process_target::install_software_single_step_breakpoints (lwp_info *lwp)
   scoped_restore save_current_thread = make_scoped_restore (&current_thread);
 
   current_thread = thread;
-  std::vector<CORE_ADDR> next_pcs = the_low_target.get_next_pcs (regcache);
+  std::vector<CORE_ADDR> next_pcs = low_get_next_pcs (regcache);
 
   for (CORE_ADDR pc : next_pcs)
     set_single_step_breakpoint (pc, current_ptid);
@@ -4131,7 +4129,7 @@ linux_process_target::single_step (lwp_info* lwp)
     {
       step = 1;
     }
-  else if (can_software_single_step ())
+  else if (supports_software_single_step ())
     {
       install_software_single_step_breakpoints (lwp);
       step = 0;
@@ -4610,7 +4608,7 @@ linux_process_target::thread_needs_step_over (thread_info *thread)
 
   /* On software single step target, resume the inferior with signal
      rather than stepping over.  */
-  if (can_software_single_step ()
+  if (supports_software_single_step ()
       && lwp->pending_signals != NULL
       && lwp_signal_can_be_delivered (lwp))
     {
@@ -5042,7 +5040,7 @@ linux_process_target::proceed_one_lwp (thread_info *thread, lwp_info *except)
       /* If resume_step is requested by GDB, install single-step
 	 breakpoints when the thread is about to be actually resumed if
 	 the single-step breakpoints weren't removed.  */
-      if (can_software_single_step ()
+      if (supports_software_single_step ()
 	  && !has_single_step_breakpoints (thread))
 	install_software_single_step_breakpoints (lwp);
 
@@ -5911,12 +5909,6 @@ linux_process_target::supports_hardware_single_step ()
 }
 
 bool
-linux_process_target::supports_software_single_step ()
-{
-  return can_software_single_step ();
-}
-
-bool
 linux_process_target::stopped_by_watchpoint ()
 {
   struct lwp_info *lwp = get_thread_lwp (current_thread);
@@ -6299,7 +6291,7 @@ linux_process_target::supports_agent ()
 bool
 linux_process_target::supports_range_stepping ()
 {
-  if (can_software_single_step ())
+  if (supports_software_single_step ())
     return true;
   if (*the_low_target.supports_range_stepping == NULL)
     return false;
diff --git a/gdbserver/linux-low.h b/gdbserver/linux-low.h
index b2f7798..2202a65 100644
--- a/gdbserver/linux-low.h
+++ b/gdbserver/linux-low.h
@@ -131,9 +131,6 @@ struct lwp_info;
 
 struct linux_target_ops
 {
-  /* Find the next possible PCs after the current instruction executes.  */
-  std::vector<CORE_ADDR> (*get_next_pcs) (struct regcache *regcache);
-
   int decr_pc_after_break;
   int (*breakpoint_at) (CORE_ADDR pc);
 
@@ -440,8 +437,6 @@ public:
 		      int *handle_len) override;
 #endif
 
-  bool supports_software_single_step () override;
-
   bool supports_catch_syscall () override;
 
   int get_ipa_tdesc_idx () override;
@@ -666,6 +661,11 @@ protected:
   virtual CORE_ADDR low_get_pc (regcache *regcache);
 
   virtual void low_set_pc (regcache *regcache, CORE_ADDR newpc);
+
+  /* Find the next possible PCs after the current instruction executes.
+     Targets that override this method should also override
+     'supports_software_single_step' to return true.  */
+  virtual std::vector<CORE_ADDR> low_get_next_pcs (regcache *regcache);
 };
 
 extern linux_process_target *the_linux_target;
diff --git a/gdbserver/linux-m32r-low.cc b/gdbserver/linux-m32r-low.cc
index 1a6771f..78e002d 100644
--- a/gdbserver/linux-m32r-low.cc
+++ b/gdbserver/linux-m32r-low.cc
@@ -160,7 +160,6 @@ m32r_target::get_regs_info ()
 }
 
 struct linux_target_ops the_low_target = {
-  NULL,
   0,
   m32r_breakpoint_at,
   NULL, /* supports_z_point_type */
diff --git a/gdbserver/linux-m68k-low.cc b/gdbserver/linux-m68k-low.cc
index 5e19ab0..00851af 100644
--- a/gdbserver/linux-m68k-low.cc
+++ b/gdbserver/linux-m68k-low.cc
@@ -255,7 +255,6 @@ m68k_supports_hardware_single_step (void)
 }
 
 struct linux_target_ops the_low_target = {
-  NULL,
   2,
   m68k_breakpoint_at,
   NULL, /* supports_z_point_type */
diff --git a/gdbserver/linux-mips-low.cc b/gdbserver/linux-mips-low.cc
index 972f431..710245c 100644
--- a/gdbserver/linux-mips-low.cc
+++ b/gdbserver/linux-mips-low.cc
@@ -966,7 +966,6 @@ mips_target::get_regs_info ()
 }
 
 struct linux_target_ops the_low_target = {
-  NULL, /* get_next_pcs */
   0,
   mips_breakpoint_at,
   mips_supports_z_point_type,
diff --git a/gdbserver/linux-nios2-low.cc b/gdbserver/linux-nios2-low.cc
index 693af71..3cae8da 100644
--- a/gdbserver/linux-nios2-low.cc
+++ b/gdbserver/linux-nios2-low.cc
@@ -277,7 +277,6 @@ nios2_target::get_regs_info ()
 
 struct linux_target_ops the_low_target =
 {
-  NULL, /* get_next_pcs */
   0,
   nios2_breakpoint_at,
 };
diff --git a/gdbserver/linux-ppc-low.cc b/gdbserver/linux-ppc-low.cc
index 9690d79..af9dc0b 100644
--- a/gdbserver/linux-ppc-low.cc
+++ b/gdbserver/linux-ppc-low.cc
@@ -3406,7 +3406,6 @@ ppc_get_ipa_tdesc_idx (void)
 }
 
 struct linux_target_ops the_low_target = {
-  NULL,
   0,
   ppc_breakpoint_at,
   ppc_supports_z_point_type,
diff --git a/gdbserver/linux-riscv-low.cc b/gdbserver/linux-riscv-low.cc
index d6f31b4..9e96504 100644
--- a/gdbserver/linux-riscv-low.cc
+++ b/gdbserver/linux-riscv-low.cc
@@ -309,7 +309,6 @@ riscv_breakpoint_at (CORE_ADDR pc)
 /* RISC-V/Linux target operations.  */
 struct linux_target_ops the_low_target =
 {
-  NULL, /* get_next_pcs */
   0,    /* decr_pc_after_break */
   riscv_breakpoint_at,
 };
diff --git a/gdbserver/linux-s390-low.cc b/gdbserver/linux-s390-low.cc
index 164142d..4c4b877 100644
--- a/gdbserver/linux-s390-low.cc
+++ b/gdbserver/linux-s390-low.cc
@@ -2826,7 +2826,6 @@ s390_emit_ops (void)
 }
 
 struct linux_target_ops the_low_target = {
-  NULL,
   s390_breakpoint_len,
   s390_breakpoint_at,
   s390_supports_z_point_type,
diff --git a/gdbserver/linux-sh-low.cc b/gdbserver/linux-sh-low.cc
index 10ee49a..47242da 100644
--- a/gdbserver/linux-sh-low.cc
+++ b/gdbserver/linux-sh-low.cc
@@ -190,7 +190,6 @@ sh_target::low_arch_setup ()
 }
 
 struct linux_target_ops the_low_target = {
-  NULL,
   0,
   sh_breakpoint_at,
   NULL, /* supports_z_point_type */
diff --git a/gdbserver/linux-sparc-low.cc b/gdbserver/linux-sparc-low.cc
index c94c3e3..f724cb8 100644
--- a/gdbserver/linux-sparc-low.cc
+++ b/gdbserver/linux-sparc-low.cc
@@ -339,7 +339,6 @@ sparc_target::get_regs_info ()
 }
 
 struct linux_target_ops the_low_target = {
-  NULL, /* get_next_pcs */
   0,
   sparc_breakpoint_at,
   NULL,  /* supports_z_point_type */
diff --git a/gdbserver/linux-tic6x-low.cc b/gdbserver/linux-tic6x-low.cc
index 69bb4f3..347b79e 100644
--- a/gdbserver/linux-tic6x-low.cc
+++ b/gdbserver/linux-tic6x-low.cc
@@ -421,7 +421,6 @@ tic6x_target::get_regs_info ()
 }
 
 struct linux_target_ops the_low_target = {
-  NULL,
   0,
   tic6x_breakpoint_at,
   NULL, /* supports_z_point_type */
diff --git a/gdbserver/linux-tile-low.cc b/gdbserver/linux-tile-low.cc
index e4565b4..86191b9 100644
--- a/gdbserver/linux-tile-low.cc
+++ b/gdbserver/linux-tile-low.cc
@@ -222,7 +222,6 @@ tile_supports_hardware_single_step (void)
 
 struct linux_target_ops the_low_target =
 {
-  NULL,
   0,
   tile_breakpoint_at,
   NULL, /* supports_z_point_type */
diff --git a/gdbserver/linux-x86-low.cc b/gdbserver/linux-x86-low.cc
index a9d7ec0..59c6b38 100644
--- a/gdbserver/linux-x86-low.cc
+++ b/gdbserver/linux-x86-low.cc
@@ -2899,7 +2899,6 @@ x86_get_ipa_tdesc_idx (void)
 
 struct linux_target_ops the_low_target =
 {
-  NULL,
   1,
   x86_breakpoint_at,
   x86_supports_z_point_type,
diff --git a/gdbserver/linux-xtensa-low.cc b/gdbserver/linux-xtensa-low.cc
index ab08227..320ac92 100644
--- a/gdbserver/linux-xtensa-low.cc
+++ b/gdbserver/linux-xtensa-low.cc
@@ -328,7 +328,6 @@ xtensa_target::get_regs_info ()
 }
 
 struct linux_target_ops the_low_target = {
-  NULL,
   0,
   xtensa_breakpoint_at,
   NULL, /* supports_z_point_type */