gdbserver/linux-low: turn watchpoint ops into methods

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

	Turn the 'stopped_by_watchpoint' and 'stopped_data_address' linux
	target ops into methods of linux_process_target.

	* linux-low.h (struct linux_target_ops): Remove the ops.
	(class linux_process_target) <check_stopped_by_watchpoint>
	<low_stopped_by_watchpoint>
	<low_stopped_data_address>: Declare.
	* linux-low.cc (check_stopped_by_watchpoint): Turn into...
	(linux_process_target::check_stopped_by_watchpoint): ...this.
	(linux_process_target::low_stopped_by_watchpoint): Define.
	(linux_process_target::low_stopped_data_address): Define.
	* linux-x86-low.cc (class x86_target) <low_stopped_by_watchpoint>
	<low_stopped_data_address>: Declare.
	(x86_stopped_by_watchpoint): Turn into...
	(x86_target::low_stopped_by_watchpoint): ...this.
	(x86_stopped_data_address): Turn into...
	(x86_target::low_stopped_data_address): ...this.
	(the_low_target): Remove the op fields.
	* linux-aarch64-low.cc (class aarch64_target)
	<low_stopped_by_watchpoint>
	<low_stopped_data_address>: Declare.
	(aarch64_stopped_by_watchpoint): Turn into...
	(aarch64_target::low_stopped_by_watchpoint): ...this.
	(aarch64_stopped_data_address): Turn into...
	(aarch64_target::low_stopped_data_address): ...this.
	(the_low_target): Remove the op fields.
	* linux-arm-low.cc (class arm_target) <low_stopped_by_watchpoint>
	<low_stopped_data_address>: Declare.
	(arm_stopped_by_watchpoint): Turn into...
	(arm_target::low_stopped_by_watchpoint): ...this.
	(arm_stopped_data_address): Turn into...
	(arm_target::low_stopped_data_address): ...this.
	(the_low_target): Remove the op fields.
	* linux-crisv32-low.cc (class crisv32_target)
	<low_stopped_by_watchpoint>
	<low_stopped_data_address>: Declare.
	(cris_stopped_by_watchpoint): Turn into...
	(crisv32_target::low_stopped_by_watchpoint): ...this.
	(cris_stopped_data_address): Turn into...
	(crisv32_target::low_stopped_data_address): ...this.
	(the_low_target): Remove the op fields.
	* linux-mips-low.cc (class mips_target) <low_stopped_by_watchpoint>
	<low_stopped_data_address>: Declare.
	(mips_stopped_by_watchpoint): Turn into...
	(mips_target::low_stopped_by_watchpoint): ...this.
	(mips_stopped_data_address): Turn into...
	(mips_target::low_stopped_data_address): ...this.
	(the_low_target): Remove the op fields.
	* linux-bfin-low.cc (the_low_target): Remove the op fields.
	* linux-m32r-low.cc (the_low_target): Ditto.
	* linux-m68k-low.cc (the_low_target): Ditto.
	* linux-ppc-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.

1 files changed, 20 insertions, 3 deletions

diff --git a/gdbserver/linux-low.h b/gdbserver/linux-low.h
index 0fdd8ce..ee2fdb8 100644
--- a/gdbserver/linux-low.h
+++ b/gdbserver/linux-low.h
@@ -131,9 +131,6 @@ struct lwp_info;
 
 struct linux_target_ops
 {
-  int (*stopped_by_watchpoint) (void);
-  CORE_ADDR (*stopped_data_address) (void);
-
   /* Hooks to reformat register data for PEEKUSR/POKEUSR (in particular
      for registers smaller than an xfer unit).  */
   void (*collect_ptrace_register) (struct regcache *regcache,
@@ -622,6 +619,22 @@ private:
   /* Install breakpoints for software single stepping.  */
   void install_software_single_step_breakpoints (lwp_info *lwp);
 
+  /* Fetch the possibly triggered data watchpoint info and store it in
+     CHILD.
+
+     On some archs, like x86, that use debug registers to set
+     watchpoints, it's possible that the way to know which watched
+     address trapped, is to check the register that is used to select
+     which address to watch.  Problem is, between setting the watchpoint
+     and reading back which data address trapped, the user may change
+     the set of watchpoints, and, as a consequence, GDB changes the
+     debug registers in the inferior.  To avoid reading back a stale
+     stopped-data-address when that happens, we cache in LP the fact
+     that a watchpoint trapped, and the corresponding data address, as
+     soon as we see CHILD stop with a SIGTRAP.  If GDB changes the debug
+     registers meanwhile, we have the cached data we can rely on.  */
+  bool check_stopped_by_watchpoint (lwp_info *child);
+
 protected:
   /* The architecture-specific "low" methods are listed below.  */
 
@@ -665,6 +678,10 @@ protected:
   virtual int low_remove_point (raw_bkpt_type type, CORE_ADDR addr,
 				int size, raw_breakpoint *bp);
 
+  virtual bool low_stopped_by_watchpoint ();
+
+  virtual CORE_ADDR low_stopped_data_address ();
+
   /* How many bytes the PC should be decremented after a break.  */
   virtual int low_decr_pc_after_break ();
 };