[PATCH v2 06/10] Replace breakpoint_reinsert_addr by get_next_pcs operation in GDBServer.

[Antoine Tremblay <antoine dot tremblay at ericsson dot com>]

This patch in preparation for software single step support on ARM. It refactors
breakpoint_reinsert_addr into get_next_pcs so that multiple location can be
returned.

When software single stepping there can be multiple possible next addresses
because we're stepping over a conditional branch instruction for example.

The operation get_next_pcs handles that by returning a vector of all the
possible next addresses.

Software breakpoints are installed at each location returned.

No regressions, tested on ubuntu 14.04 ARMv7 and x86.
With gdbserver-{native,extended} / { -marm -mthumb }

gdb/ChangeLog:

	* common/get-next-pcs.h: New file.
	* common/gdb_vecs.h: Add CORE_ADDR vect.
	* symtab.h: Move CORE_ADDR vect to gdb_vecs.h.

gdb/gdbserver/ChangeLog:
	* linux-aarch64-low.c (struct linux_target_ops): Rename
	breakpoint_reinsert_addr to get_next_pcs.
	* linux-arm-low.c (struct linux_target_ops): Likewise.
	* linux-bfin-low.c (struct linux_target_ops): Likewise.
	* linux-cris-low.c (struct linux_target_ops): Likewise.
	* linux-crisv32-low.c (struct linux_target_ops): Likewise.
	* linux-low.c (can_software_single_step): Likewise.
	(install_software_single_step_breakpoints): New function.
	(start_step_over): Use install_software_single_step_breakpoints.
	* linux-low.h: Rename breakpoint_reinsert_addr to
	get_next_pcs.
	* linux-mips-low.c (struct linux_target_ops): Likewise.
	* linux-nios2-low.c (struct linux_target_ops): Likewise.
	* linux-sparc-low.c (struct linux_target_ops): Likewise.
---
 gdb/common/gdb_vecs.h             |  2 ++
 gdb/common/get-next-pcs.h         | 39 +++++++++++++++++++++++++++++++++++++++
 gdb/gdbserver/linux-aarch64-low.c |  2 +-
 gdb/gdbserver/linux-arm-low.c     |  2 +-
 gdb/gdbserver/linux-bfin-low.c    |  2 +-
 gdb/gdbserver/linux-cris-low.c    |  2 +-
 gdb/gdbserver/linux-crisv32-low.c |  2 +-
 gdb/gdbserver/linux-low.c         | 31 +++++++++++++++++++++++++++----
 gdb/gdbserver/linux-low.h         |  6 +++++-
 gdb/gdbserver/linux-mips-low.c    |  2 +-
 gdb/gdbserver/linux-nios2-low.c   |  2 +-
 gdb/gdbserver/linux-sparc-low.c   |  2 +-
 gdb/symtab.h                      |  2 --
 13 files changed, 81 insertions(+), 15 deletions(-)
 create mode 100644 gdb/common/get-next-pcs.h

diff --git a/gdb/common/gdb_vecs.h b/gdb/common/gdb_vecs.h
index b3f56f8..1ed6182 100644
--- a/gdb/common/gdb_vecs.h
+++ b/gdb/common/gdb_vecs.h
@@ -31,6 +31,8 @@ DEF_VEC_P (const_char_ptr);
 
 DEF_VEC_I (int);
 
+DEF_VEC_I(CORE_ADDR);
+
 extern void free_char_ptr_vec (VEC (char_ptr) *char_ptr_vec);
 
 extern struct cleanup *
diff --git a/gdb/common/get-next-pcs.h b/gdb/common/get-next-pcs.h
new file mode 100644
index 0000000..76bf6fc
--- /dev/null
+++ b/gdb/common/get-next-pcs.h
@@ -0,0 +1,39 @@
+/* Common code for software single stepping support.
+
+   Copyright (C) 2015 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 GET_NEXT_PCS_H
+#define GET_NEXT_PCS_H 1
+
+#include "gdb_vecs.h"
+
+/* This structure contains the shared context of a get_next_pcs call, as
+   used in linux target operation "get_next_pcs" in GDBServer and the
+   software_single_step architecture dependent function in GDB.  */
+
+struct get_next_pcs
+{
+  /* Resulting vector of possible next addresses.  */
+  VEC (CORE_ADDR) *result;
+  /* Base PC from which to get the next pcs.  */
+  CORE_ADDR pc;
+  /* The cache for registry values.  */
+  struct regcache* regcache;
+};
+
+#endif /* GET_NEXT_PCS_H */
diff --git a/gdb/gdbserver/linux-aarch64-low.c b/gdb/gdbserver/linux-aarch64-low.c
index a0bc1c2..3e21042 100644
--- a/gdb/gdbserver/linux-aarch64-low.c
+++ b/gdb/gdbserver/linux-aarch64-low.c
@@ -2959,7 +2959,7 @@ struct linux_target_ops the_low_target =
   aarch64_set_pc,
   NULL, /* breakpoint_kind_from_pc */
   aarch64_sw_breakpoint_from_kind,
-  NULL, /* breakpoint_reinsert_addr */
+  NULL, /* get_next_pcs */
   0,    /* decr_pc_after_break */
   aarch64_breakpoint_at,
   aarch64_supports_z_point_type,
diff --git a/gdb/gdbserver/linux-arm-low.c b/gdb/gdbserver/linux-arm-low.c
index 0a82289..12b7909 100644
--- a/gdb/gdbserver/linux-arm-low.c
+++ b/gdb/gdbserver/linux-arm-low.c
@@ -1029,7 +1029,7 @@ struct linux_target_ops the_low_target = {
   arm_set_pc,
   arm_breakpoint_kind_from_pc,
   arm_sw_breakpoint_from_kind,
-  NULL, /* breakpoint_reinsert_addr */
+  NULL, /* get_next_pcs */
   0,
   arm_breakpoint_at,
   arm_supports_z_point_type,
diff --git a/gdb/gdbserver/linux-bfin-low.c b/gdb/gdbserver/linux-bfin-low.c
index 912d253..1de2f78 100644
--- a/gdb/gdbserver/linux-bfin-low.c
+++ b/gdb/gdbserver/linux-bfin-low.c
@@ -141,7 +141,7 @@ struct linux_target_ops the_low_target = {
   bfin_set_pc,
   NULL, /* breakpoint_kind_from_pc */
   bfin_sw_breakpoint_from_kind,
-  NULL, /* breakpoint_reinsert_addr */
+  NULL, /* get_next_pcs */
   2,
   bfin_breakpoint_at,
   NULL, /* supports_z_point_type */
diff --git a/gdb/gdbserver/linux-cris-low.c b/gdb/gdbserver/linux-cris-low.c
index 9f4519c..6902a45 100644
--- a/gdb/gdbserver/linux-cris-low.c
+++ b/gdb/gdbserver/linux-cris-low.c
@@ -139,7 +139,7 @@ struct linux_target_ops the_low_target = {
   cris_set_pc,
   NULL, /* breakpoint_kind_from_pc */
   cris_sw_breakpoint_from_kind,
-  NULL, /* breakpoint_reinsert_addr */
+  NULL, /* get_next_pcs */
   0,
   cris_breakpoint_at,
 };
diff --git a/gdb/gdbserver/linux-crisv32-low.c b/gdb/gdbserver/linux-crisv32-low.c
index 2404d0e..28c1981 100644
--- a/gdb/gdbserver/linux-crisv32-low.c
+++ b/gdb/gdbserver/linux-crisv32-low.c
@@ -422,7 +422,7 @@ struct linux_target_ops the_low_target = {
   cris_set_pc,
   NULL, /* breakpoint_kind_from_pc */
   cris_sw_breakpoint_from_kind,
-  NULL, /* breakpoint_reinsert_addr */
+  NULL, /* get_next_pcs */
   0,
   cris_breakpoint_at,
   cris_supports_z_point_type,
diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index ce9cc2e..2997d58 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -54,6 +54,7 @@
 #include <elf.h>
 #endif
 #include "nat/linux-namespaces.h"
+#include "common/get-next-pcs.h"
 
 #ifndef SPUFS_MAGIC
 #define SPUFS_MAGIC 0x23c9b64e
@@ -281,12 +282,12 @@ can_hardware_single_step (void)
 }
 
 /* True if the low target can software single-step.  Such targets
-   implement the BREAKPOINT_REINSERT_ADDR callback.  */
+   implement the GET_NEXT_PCS callback.  */
 
 static int
 can_software_single_step (void)
 {
-  return (the_low_target.breakpoint_reinsert_addr != NULL);
+  return (the_low_target.get_next_pcs != NULL);
 }
 
 /* True if the low target supports memory breakpoints.  If so, we'll
@@ -3876,6 +3877,29 @@ enqueue_pending_signal (struct lwp_info *lwp, int signal, siginfo_t *info)
   lwp->pending_signals = p_sig;
 }
 
+/* Install breakpoints for software single stepping.  */
+
+static void
+install_software_single_step_breakpoints (struct lwp_info *lwp)
+{
+  struct get_next_pcs next_pcs;
+  int i;
+  CORE_ADDR pc;
+  struct regcache *regcache = get_thread_regcache (current_thread, 1);
+
+  next_pcs.pc = get_pc (lwp);
+  next_pcs.regcache = regcache;
+  next_pcs.result = NULL;
+  (*the_low_target.get_next_pcs) (&next_pcs);
+
+  for (i = 0; VEC_iterate (CORE_ADDR, next_pcs.result, i, pc); ++i)
+    {
+      set_reinsert_breakpoint (pc);
+    }
+
+  VEC_free (CORE_ADDR, next_pcs.result);
+}
+
 /* Resume execution of LWP.  If STEP is nonzero, single-step it.  If
    SIGNAL is nonzero, give it that signal.  */
 
@@ -4439,8 +4463,7 @@ start_step_over (struct lwp_info *lwp)
     }
   else if (can_software_single_step ())
     {
-      CORE_ADDR raddr = (*the_low_target.breakpoint_reinsert_addr) ();
-      set_reinsert_breakpoint (raddr);
+      install_software_single_step_breakpoints (lwp);
       step = 0;
     }
   else
diff --git a/gdb/gdbserver/linux-low.h b/gdb/gdbserver/linux-low.h
index d60d97d..6bb638f 100644
--- a/gdb/gdbserver/linux-low.h
+++ b/gdb/gdbserver/linux-low.h
@@ -29,6 +29,9 @@
 
 #define PTRACE_XFER_TYPE long
 
+/* Forward declaration for get_next_pcs.  */
+struct get_next_pcs;
+
 #ifdef HAVE_LINUX_REGSETS
 typedef void (*regset_fill_func) (struct regcache *, void *);
 typedef void (*regset_store_func) (struct regcache *, const void *);
@@ -153,7 +156,8 @@ struct linux_target_ops
   /* See target.h for details.  */
   const gdb_byte *(*sw_breakpoint_from_kind) (int kind, int *size);
 
-  CORE_ADDR (*breakpoint_reinsert_addr) (void);
+  /* Find the next possible PCs after the current instruction executes.  */
+  void (*get_next_pcs) (struct get_next_pcs *next_pcs);
 
   int decr_pc_after_break;
   int (*breakpoint_at) (CORE_ADDR pc);
diff --git a/gdb/gdbserver/linux-mips-low.c b/gdb/gdbserver/linux-mips-low.c
index 32a91a8..5edc097 100644
--- a/gdb/gdbserver/linux-mips-low.c
+++ b/gdb/gdbserver/linux-mips-low.c
@@ -880,7 +880,7 @@ struct linux_target_ops the_low_target = {
   mips_set_pc,
   NULL, /* breakpoint_kind_from_pc */
   mips_sw_breakpoint_from_kind,
-  NULL, /* breakpoint_reinsert_addr */
+  NULL, /* get_next_pcs */
   0,
   mips_breakpoint_at,
   mips_supports_z_point_type,
diff --git a/gdb/gdbserver/linux-nios2-low.c b/gdb/gdbserver/linux-nios2-low.c
index 9380c3b..1accc03 100644
--- a/gdb/gdbserver/linux-nios2-low.c
+++ b/gdb/gdbserver/linux-nios2-low.c
@@ -267,7 +267,7 @@ struct linux_target_ops the_low_target =
   nios2_set_pc,
   NULL, /* breakpoint_kind_from_pc */
   nios2_sw_breakpoint_from_kind,
-  NULL, /* breakpoint_reinsert_addr */
+  NULL, /* get_next_pcs */
   0,
   nios2_breakpoint_at,
 };
diff --git a/gdb/gdbserver/linux-sparc-low.c b/gdb/gdbserver/linux-sparc-low.c
index 54a849c..bfdd8c1 100644
--- a/gdb/gdbserver/linux-sparc-low.c
+++ b/gdb/gdbserver/linux-sparc-low.c
@@ -320,7 +320,7 @@ struct linux_target_ops the_low_target = {
   NULL,
   NULL, /* breakpoint_kind_from_pc */
   sparc_sw_breakpoint_from_kind,
-  NULL, /* breakpoint_reinsert_addr */
+  NULL, /* get_next_pcs */
   0,
   sparc_breakpoint_at,
   NULL,  /* supports_z_point_type */
diff --git a/gdb/symtab.h b/gdb/symtab.h
index 477befd..bdc0921 100644
--- a/gdb/symtab.h
+++ b/gdb/symtab.h
@@ -1607,8 +1607,6 @@ void iterate_over_symtabs (const char *name,
 					    void *data),
 			   void *data);
 
-DEF_VEC_I (CORE_ADDR);
-
 VEC (CORE_ADDR) *find_pcs_for_symtab_line (struct symtab *symtab, int line,
 					   struct linetable_entry **best_entry);
 
-- 
2.6.2