[v2,5/7] Implement breakpoint_from_pc for ARM in GDBServer.

diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index d5ca2ee..14ad405 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -657,7 +657,7 @@  ALL_64_TARGET_OBS = \
 
 # All other target-dependent objects files (used with --enable-targets=all).
 ALL_TARGET_OBS = \
-	armbsd-tdep.o arm-linux-tdep.o arm-symbian-tdep.o \
+	armbsd-tdep.o arm.o arm-linux-tdep.o arm-symbian-tdep.o \
 	armnbsd-tdep.o armobsd-tdep.o \
 	arm-tdep.o arm-wince-tdep.o \
 	avr-tdep.o \
@@ -1660,6 +1660,7 @@  ALLDEPFILES = \
 	amd64-dicos-tdep.c \
 	amd64-linux-nat.c amd64-linux-tdep.c \
 	amd64-sol2-tdep.c \
+	arm.c \
 	arm-linux-nat.c arm-linux-tdep.c arm-symbian-tdep.c arm-tdep.c \
 	armnbsd-nat.c armbsd-tdep.c armnbsd-tdep.c armobsd-tdep.c \
 	avr-tdep.c \
@@ -2275,6 +2276,16 @@  waitstatus.o: ${srcdir}/target/waitstatus.c
 	$(COMPILE) $(srcdir)/target/waitstatus.c
 	$(POSTCOMPILE)
 
+#
+# gdb/arch/ dependencies
+#
+# Need to explicitly specify the compile rule as make will do nothing
+# or try to compile the object file into the sub-directory.
+
+arm.o: ${srcdir}/arch/arm.c
+	$(COMPILE) $(srcdir)/arch/arm.c
+	$(POSTCOMPILE)
+
 # gdb/nat/ dependencies
 #
 # Need to explicitly specify the compile rule as make will do nothing
diff --git a/gdb/arch/arm.c b/gdb/arch/arm.c
new file mode 100644
index 0000000..a83175a
--- /dev/null
+++ b/gdb/arch/arm.c
@@ -0,0 +1,32 @@ 
+/* Common target dependent code for GDB on ARM systems.
+
+   Copyright (C) 1988-2015 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/>.  */
+
+#include "arm.h"
+
+/* Return the size in bytes of the complete Thumb instruction whose
+   first halfword is INST1.  */
+
+int
+thumb_insn_size (unsigned short inst1)
+{
+  if ((inst1 & 0xe000) == 0xe000 && (inst1 & 0x1800) != 0)
+    return 4;
+  else
+    return 2;
+}
diff --git a/gdb/arch/arm.h b/gdb/arch/arm.h
index e0eed60..a054776 100644
--- a/gdb/arch/arm.h
+++ b/gdb/arch/arm.h
@@ -1,5 +1,5 @@ 
 /* Common target dependent code for GDB on ARM systems.
-   Copyright (C) 2002-2015 Free Software Foundation, Inc.
+   Copyright (C) 1988-2015 Free Software Foundation, Inc.
 
    This file is part of GDB.
 
@@ -58,4 +58,14 @@  enum gdb_regnum {
   ARM_LAST_FP_ARG_REGNUM = ARM_F3_REGNUM
 };
 
+/* Addresses for calling Thumb functions have the bit 0 set.
+   Here are some macros to test, set, or clear bit 0 of addresses.  */
+#define IS_THUMB_ADDR(addr)    ((addr) & 1)
+#define MAKE_THUMB_ADDR(addr)  ((addr) | 1)
+#define UNMAKE_THUMB_ADDR(addr) ((addr) & ~1)
+
+/* Return the size in bytes of the complete Thumb instruction whose
+   first halfword is INST1.  */
+int thumb_insn_size (unsigned short inst1);
+
 #endif
diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
index 4c99ddf..aad2ce6 100644
--- a/gdb/arm-tdep.c
+++ b/gdb/arm-tdep.c
@@ -45,6 +45,7 @@ 
 #include "user-regs.h"
 #include "observer.h"
 
+#include "arch/arm.h"
 #include "arm-tdep.h"
 #include "gdb/sim-arm.h"
 
@@ -235,8 +236,6 @@  static void arm_neon_quad_write (struct gdbarch *gdbarch,
 				 struct regcache *regcache,
 				 int regnum, const gdb_byte *buf);
 
-static int thumb_insn_size (unsigned short inst1);
-
 struct arm_prologue_cache
 {
   /* The stack pointer at the time this frame was created; i.e. the
@@ -267,12 +266,6 @@  static CORE_ADDR arm_analyze_prologue (struct gdbarch *gdbarch,
 
 #define DISPLACED_STEPPING_ARCH_VERSION		5
 
-/* Addresses for calling Thumb functions have the bit 0 set.
-   Here are some macros to test, set, or clear bit 0 of addresses.  */
-#define IS_THUMB_ADDR(addr)	((addr) & 1)
-#define MAKE_THUMB_ADDR(addr)	((addr) | 1)
-#define UNMAKE_THUMB_ADDR(addr) ((addr) & ~1)
-
 /* Set to true if the 32-bit mode is in use.  */
 
 int arm_apcs_32 = 1;
@@ -4364,18 +4357,6 @@  bitcount (unsigned long val)
   return nbits;
 }
 
-/* Return the size in bytes of the complete Thumb instruction whose
-   first halfword is INST1.  */
-
-static int
-thumb_insn_size (unsigned short inst1)
-{
-  if ((inst1 & 0xe000) == 0xe000 && (inst1 & 0x1800) != 0)
-    return 4;
-  else
-    return 2;
-}
-
 static int
 thumb_advance_itstate (unsigned int itstate)
 {
diff --git a/gdb/configure.tgt b/gdb/configure.tgt
index 33d4cfc..2e824ad 100644
--- a/gdb/configure.tgt
+++ b/gdb/configure.tgt
@@ -44,7 +44,7 @@  aarch64*-*-elf)
 aarch64*-*-linux*)
 	# Target: AArch64 linux
 	gdb_target_obs="aarch64-tdep.o aarch64-linux-tdep.o aarch64-insn.o \
-			arm-tdep.o arm-linux-tdep.o \
+			arm.o arm-tdep.o arm-linux-tdep.o \
 			glibc-tdep.o linux-tdep.o solib-svr4.o \
 			symfile-mem.o linux-record.o"
 	build_gdbserver=yes
@@ -84,31 +84,31 @@  am33_2.0*-*-linux*)
 
 arm*-wince-pe | arm*-*-mingw32ce*)
 	# Target: ARM based machine running Windows CE (win32)
-	gdb_target_obs="arm-tdep.o arm-wince-tdep.o windows-tdep.o"
+	gdb_target_obs="arm.o arm-tdep.o arm-wince-tdep.o windows-tdep.o"
 	build_gdbserver=yes
 	;;
 arm*-*-linux*)
 	# Target: ARM based machine running GNU/Linux
-	gdb_target_obs="arm-tdep.o arm-linux-tdep.o glibc-tdep.o \
+	gdb_target_obs="arm.o arm-tdep.o arm-linux-tdep.o glibc-tdep.o \
 			solib-svr4.o symfile-mem.o linux-tdep.o linux-record.o"
 	build_gdbserver=yes
 	;;
 arm*-*-netbsd* | arm*-*-knetbsd*-gnu)
 	# Target: NetBSD/arm
-	gdb_target_obs="arm-tdep.o armnbsd-tdep.o solib-svr4.o"
+	gdb_target_obs="arm.o arm-tdep.o armnbsd-tdep.o solib-svr4.o"
 	;;
 arm*-*-openbsd*)
 	# Target: OpenBSD/arm
-	gdb_target_obs="arm-tdep.o armbsd-tdep.o armobsd-tdep.o obsd-tdep.o \
-			solib-svr4.o"
+	gdb_target_obs="arm.o arm-tdep.o armbsd-tdep.o armobsd-tdep.o \
+			obsd-tdep.o solib-svr4.o"
 	;;
 arm*-*-symbianelf*)
 	# Target: SymbianOS/arm
-	gdb_target_obs="arm-tdep.o arm-symbian-tdep.o"
+	gdb_target_obs="arm.o arm-tdep.o arm-symbian-tdep.o"
 	;;
 arm*-*-*)
 	# Target: ARM embedded system
-	gdb_target_obs="arm-tdep.o"
+	gdb_target_obs="arm.o arm-tdep.o"
 	gdb_sim=../sim/arm/libsim.a
 	;;
 
diff --git a/gdb/gdbserver/Makefile.in b/gdb/gdbserver/Makefile.in
index cd146f4..97e1e62 100644
--- a/gdb/gdbserver/Makefile.in
+++ b/gdb/gdbserver/Makefile.in
@@ -180,7 +180,8 @@  SFILES=	$(srcdir)/gdbreplay.c $(srcdir)/inferiors.c $(srcdir)/dll.c \
 	$(srcdir)/common/common-debug.c $(srcdir)/common/cleanups.c \
 	$(srcdir)/common/common-exceptions.c $(srcdir)/symbol.c \
 	$(srcdir)/common/btrace-common.c \
-	$(srcdir)/common/fileio.c $(srcdir)/nat/linux-namespaces.c
+	$(srcdir)/common/fileio.c $(srcdir)/nat/linux-namespaces.c \
+	$(srcdir)/arch/arm.c
 
 DEPFILES = @GDBSERVER_DEPFILES@
 
@@ -583,6 +584,12 @@  fileio.o: ../common/fileio.c
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
+# Arch object files rules form ../arch
+
+arm.o: ../arch/arm.c
+	$(COMPILE) $<
+	$(POSTCOMPILE)
+
 # Native object files rules from ../nat
 
 x86-dregs.o: ../nat/x86-dregs.c
diff --git a/gdb/gdbserver/configure.srv b/gdb/gdbserver/configure.srv
index f187c9d..e854110 100644
--- a/gdb/gdbserver/configure.srv
+++ b/gdb/gdbserver/configure.srv
@@ -70,6 +70,7 @@  case "${target}" in
 			srv_regobj="${srv_regobj} arm-with-neon.o"
 			srv_tgtobj="$srv_linux_obj linux-arm-low.o"
 			srv_tgtobj="$srv_tgtobj linux-aarch32-low.o"
+			srv_tgtobj="${srv_tgtobj} arm.o"
 			srv_xmlfiles="arm-with-iwmmxt.xml"
 			srv_xmlfiles="${srv_xmlfiles} arm-with-vfpv2.xml"
 			srv_xmlfiles="${srv_xmlfiles} arm-with-vfpv3.xml"
diff --git a/gdb/gdbserver/linux-arm-low.c b/gdb/gdbserver/linux-arm-low.c
index 367c704..8f420f9 100644
--- a/gdb/gdbserver/linux-arm-low.c
+++ b/gdb/gdbserver/linux-arm-low.c
@@ -30,6 +30,8 @@ 
 #include "nat/gdb_ptrace.h"
 #include <signal.h>
 
+#include "arch/arm.h"
+
 /* Defined in auto-generated files.  */
 void init_registers_arm (void);
 extern const struct target_desc *tdesc_arm;
@@ -237,7 +239,9 @@  arm_set_pc (struct regcache *regcache, CORE_ADDR pc)
 static const unsigned long arm_breakpoint = 0xef9f0001;
 #define arm_breakpoint_len 4
 static const unsigned short thumb_breakpoint = 0xde01;
+#define thumb_breakpoint_len 2
 static const unsigned short thumb2_breakpoint[] = { 0xf7f0, 0xa000 };
+#define thumb2_breakpoint_len 4
 
 /* For new EABI binaries.  We recognize it regardless of which ABI
    is used for gdbserver, so single threaded debugging should work
@@ -285,6 +289,50 @@  arm_breakpoint_at (CORE_ADDR where)
   return 0;
 }
 
+/* Determine the type and size of breakpoint to insert at PCPTR.  Uses
+   the program counter value to determine whether a 16-bit or 32-bit
+   breakpoint should be used.  It returns a pointer to a string of
+   bytes that encode a breakpoint instruction, stores the length of
+   the string to *lenptr, and adjusts the program counter (if
+   necessary) to point to the actual memory location where the
+   breakpoint should be inserted.  */
+
+static const unsigned char *
+arm_breakpoint_from_pc (CORE_ADDR *pcptr, int *lenptr)
+{
+  if (IS_THUMB_ADDR (*pcptr))
+    {
+      gdb_byte buf[2];
+
+      *pcptr = UNMAKE_THUMB_ADDR (*pcptr);
+
+      /* Check whether we are replacing a thumb2 32-bit instruction.  */
+      if ((*the_target->read_memory) (*pcptr, buf, 2) == 0)
+	{
+	  unsigned short inst1 = 0;
+
+	  (*the_target->read_memory) (*pcptr, (gdb_byte *) &inst1, 2);
+	  if (thumb_insn_size (inst1) == 4)
+	    {
+	      *lenptr = thumb2_breakpoint_len;
+	      return (unsigned char *) &thumb2_breakpoint;
+	    }
+	}
+
+      *lenptr = thumb_breakpoint_len;
+      return (unsigned char *) &thumb_breakpoint;
+    }
+  else
+    {
+      *lenptr = arm_breakpoint_len;
+#ifndef __ARM_EABI__
+      return (const unsigned char *) &arm_breakpoint;
+#else
+      return (const unsigned char *) &arm_eabi_breakpoint;
+#endif
+    }
+}
+
 /* We only place breakpoints in empty marker functions, and thread locking
    is outside of the function.  So rather than importing software single-step,
    we can just run until exit.  */
@@ -913,21 +961,6 @@  arm_regs_info (void)
     return &regs_info_arm;
 }
 
-static const unsigned char *
-arm_breakpoint_from_pc (CORE_ADDR *pcptr, int *len)
-{
-  *len = arm_breakpoint_len;
-   /* Define an ARM-mode breakpoint; we only set breakpoints in the C
-     library, which is most likely to be ARM.  If the kernel supports
-     clone events, we will never insert a breakpoint, so even a Thumb
-     C library will work; so will mixing EABI/non-EABI gdbserver and
-     application.  */
-#ifndef __ARM_EABI__
-  return (const unsigned char *) &arm_breakpoint;
-#else
-  return (const unsigned char *) &arm_eabi_breakpoint;
-#endif
-}
 struct linux_target_ops the_low_target = {
   arm_arch_setup,
   arm_regs_info,