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

Antoine Tremblay
2015-10-29T17:10:05Z

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 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 isntall_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 | 34 ++++++++++++++++++++++++++++++++++
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, 76 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..dfe3461
--- /dev/null
+++ b/gdb/common/get-next-pcs.h
@@ -0,0 +1,34 @@
+/* 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"
+
+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;
+ 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 8e32fae..0b87367 100644
--- a/gdb/gdbserver/linux-arm-low.c
+++ b/gdb/gdbserver/linux-arm-low.c
@@ -1027,7 +1027,7 @@ 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 a3b0f3a..1f423ba 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 = VEC_alloc (CORE_ADDR, 1);
+ (*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);

--
1.9.1