gdbarch software_single_step returns VEC (CORE_ADDR) *

This patch changes gdbarch method software_single_step to return a
vector of addresses on which GDB should insert breakpoints, and don't
insert breakpoints.  Instead, the caller of
gdbarch_software_single_step inserts breakpoints if the returned
vector is not NULL.

gdb:

2016-11-08  Yao Qi  <yao.qi@linaro.org>

	* aarch64-tdep.c (aarch64_software_single_step): Return
	VEC (CORE_ADDR) *.  Return NULL instead of 0.  Don't call
	insert_single_step_breakpoint.
	* alpha-tdep.c (alpha_deal_with_atomic_sequence): Likewise.
	(alpha_software_single_step): Likewise.
	* alpha-tdep.h (alpha_software_single_step): Update declaration.
	* arm-linux-tdep.c (arm_linux_software_single_step): Return
	VEC (CORE_ADDR) *.  Return NULL instead of 0.
	* arm-tdep.c (arm_software_single_step): Return NULL instead of	0.
	* arm-tdep.h (arm_software_single_step): Update declaration.
	* breakpoint.c (insert_single_step_breakpoints): New function.
	* breakpoint.h (insert_single_step_breakpoints): Declare.
	* cris-tdep.c (cris_software_single_step): Return
	VEC (CORE_ADDR) *.  Don't call insert_single_step_breakpoint.
	* gdbarch.sh (software_single_step): Change it to return
	VEC (CORE_ADDR) *.
	* gdbarch.c, gdbarch.h: Regenerated.
	* infrun.c (maybe_software_singlestep): Adjust.
	* mips-tdep.c (mips_deal_with_atomic_sequence): Return
	VEC (CORE_ADDR) *.  Don't call insert_single_step_breakpoint.
	(micromips_deal_with_atomic_sequence): Likewise.
	(deal_with_atomic_sequence): Likewise.
	(mips_software_single_step): Likewise.
	* mips-tdep.h (mips_software_single_step): Update declaration.
	* moxie-tdep.c (moxie_software_single_step): Likewise.
	* nios2-tdep.c (nios2_software_single_step): Likewise.
	* ppc-tdep.h (ppc_deal_with_atomic_sequence): Update
	declaration.
	* record-full.c (record_full_resume): Adjust.
	(record_full_wait_1): Likewise.
	* rs6000-aix-tdep.c (rs6000_software_single_step): Return
	VEC (CORE_ADDR) *.  Don't call insert_single_step_breakpoint.
	* rs6000-tdep.c	(ppc_deal_with_atomic_sequence): Return
	VEC (CORE_ADDR) *.  Don't call insert_single_step_breakpoint.
	* s390-linux-tdep.c (s390_software_single_step): Likewise.
	* sparc-tdep.c (sparc_software_single_step): Likewise.
	* spu-tdep.c (spu_software_single_step): Likewise.
	* tic6x-tdep.c (tic6x_software_single_step): Likewise.

gdb/ChangeLog

@@ -1,3 +1,44 @@
+2016-11-08  Yao Qi  <yao.qi@linaro.org>
+
+	* aarch64-tdep.c (aarch64_software_single_step): Return
+	VEC (CORE_ADDR) *.  Return NULL instead of 0.  Don't call
+	insert_single_step_breakpoint.
+	* alpha-tdep.c (alpha_deal_with_atomic_sequence): Likewise.
+	(alpha_software_single_step): Likewise.
+	* alpha-tdep.h (alpha_software_single_step): Update declaration.
+	* arm-linux-tdep.c (arm_linux_software_single_step): Return
+	VEC (CORE_ADDR) *.  Return NULL instead of 0.
+	* arm-tdep.c (arm_software_single_step): Return NULL instead of	0.
+	* arm-tdep.h (arm_software_single_step): Update declaration.
+	* breakpoint.c (insert_single_step_breakpoints): New function.
+	* breakpoint.h (insert_single_step_breakpoints): Declare.
+	* cris-tdep.c (cris_software_single_step): Return
+	VEC (CORE_ADDR) *.  Don't call insert_single_step_breakpoint.
+	* gdbarch.sh (software_single_step): Change it to return
+	VEC (CORE_ADDR) *.
+	* gdbarch.c, gdbarch.h: Regenerated.
+	* infrun.c (maybe_software_singlestep): Adjust.
+	* mips-tdep.c (mips_deal_with_atomic_sequence): Return
+	VEC (CORE_ADDR) *.  Don't call insert_single_step_breakpoint.
+	(micromips_deal_with_atomic_sequence): Likewise.
+	(deal_with_atomic_sequence): Likewise.
+	(mips_software_single_step): Likewise.
+	* mips-tdep.h (mips_software_single_step): Update declaration.
+	* moxie-tdep.c (moxie_software_single_step): Likewise.
+	* nios2-tdep.c (nios2_software_single_step): Likewise.
+	* ppc-tdep.h (ppc_deal_with_atomic_sequence): Update
+	declaration.
+	* record-full.c (record_full_resume): Adjust.
+	(record_full_wait_1): Likewise.
+	* rs6000-aix-tdep.c (rs6000_software_single_step): Return
+	VEC (CORE_ADDR) *.  Don't call insert_single_step_breakpoint.
+	* rs6000-tdep.c	(ppc_deal_with_atomic_sequence): Return
+	VEC (CORE_ADDR) *.  Don't call insert_single_step_breakpoint.
+	* s390-linux-tdep.c (s390_software_single_step): Likewise.
+	* sparc-tdep.c (sparc_software_single_step): Likewise.
+	* spu-tdep.c (spu_software_single_step): Likewise.
+	* tic6x-tdep.c (tic6x_software_single_step): Likewise.
+
 2016-11-08  Yao Qi  <yao.qi@linaro.org>
 
 	* arm-linux-tdep.c (arm_linux_software_single_step): Write

gdb/aarch64-tdep.c

@@ -2224,11 +2224,10 @@ value_of_aarch64_user_reg (struct frame_info *frame, const void *baton)
 /* Implement the "software_single_step" gdbarch method, needed to
    single step through atomic sequences on AArch64.  */
 
-static int
+static VEC (CORE_ADDR) *
 aarch64_software_single_step (struct frame_info *frame)
 {
   struct gdbarch *gdbarch = get_frame_arch (frame);
-  struct address_space *aspace = get_frame_address_space (frame);
   enum bfd_endian byte_order_for_code = gdbarch_byte_order_for_code (gdbarch);
   const int insn_size = 4;
   const int atomic_sequence_length = 16; /* Instruction sequence length.  */
@@ -2243,13 +2242,14 @@ aarch64_software_single_step (struct frame_info *frame)
   int bc_insn_count = 0; /* Conditional branch instruction count.  */
   int last_breakpoint = 0; /* Defaults to 0 (no breakpoints placed).  */
   aarch64_inst inst;
+  VEC (CORE_ADDR) *next_pcs = NULL;
 
   if (aarch64_decode_insn (insn, &inst, 1) != 0)
-    return 0;
+    return NULL;
 
   /* Look for a Load Exclusive instruction which begins the sequence.  */
   if (inst.opcode->iclass != ldstexcl || bit (insn, 22) == 0)
-    return 0;
+    return NULL;
 
   for (insn_count = 0; insn_count < atomic_sequence_length; ++insn_count)
     {
@@ -2258,14 +2258,14 @@ aarch64_software_single_step (struct frame_info *frame)
 					   byte_order_for_code);
 
       if (aarch64_decode_insn (insn, &inst, 1) != 0)
-	return 0;
+	return NULL;
       /* Check if the instruction is a conditional branch.  */
       if (inst.opcode->iclass == condbranch)
 	{
 	  gdb_assert (inst.operands[0].type == AARCH64_OPND_ADDR_PCREL19);
 
 	  if (bc_insn_count >= 1)
-	    return 0;
+	    return NULL;
 
 	  /* It is, so we'll try to set a breakpoint at the destination.  */
 	  breaks[1] = loc + inst.operands[0].imm.value;
@@ -2284,7 +2284,7 @@ aarch64_software_single_step (struct frame_info *frame)
 
   /* We didn't find a closing Store Exclusive instruction, fall back.  */
   if (!closing_insn)
-    return 0;
+    return NULL;
 
   /* Insert breakpoint after the end of the atomic sequence.  */
   breaks[0] = loc + insn_size;
@@ -2299,9 +2299,9 @@ aarch64_software_single_step (struct frame_info *frame)
   /* Insert the breakpoint at the end of the sequence, and one at the
      destination of the conditional branch, if it exists.  */
   for (index = 0; index <= last_breakpoint; index++)
-    insert_single_step_breakpoint (gdbarch, aspace, breaks[index]);
+    VEC_safe_push (CORE_ADDR, next_pcs, breaks[index]);
 
-  return 1;
+  return next_pcs;
 }
 
 struct displaced_step_closure

gdb/alpha-tdep.c

@@ -765,11 +765,10 @@ static const int stq_c_opcode = 0x2f;
    is found, attempt to step through it.  A breakpoint is placed at the end of 
    the sequence.  */
 
-static int 
+static VEC (CORE_ADDR) *
 alpha_deal_with_atomic_sequence (struct frame_info *frame)
 {
   struct gdbarch *gdbarch = get_frame_arch (frame);
-  struct address_space *aspace = get_frame_address_space (frame);
   CORE_ADDR pc = get_frame_pc (frame);
   CORE_ADDR breaks[2] = {-1, -1};
   CORE_ADDR loc = pc;
@@ -780,11 +779,12 @@ alpha_deal_with_atomic_sequence (struct frame_info *frame)
   int last_breakpoint = 0; /* Defaults to 0 (no breakpoints placed).  */  
   const int atomic_sequence_length = 16; /* Instruction sequence length.  */
   int bc_insn_count = 0; /* Conditional branch instruction count.  */
+  VEC (CORE_ADDR) *next_pcs = NULL;
 
   /* Assume all atomic sequences start with a LDL_L/LDQ_L instruction.  */
   if (INSN_OPCODE (insn) != ldl_l_opcode
       && INSN_OPCODE (insn) != ldq_l_opcode)
-    return 0;
+    return NULL;
 
   /* Assume that no atomic sequence is longer than "atomic_sequence_length" 
      instructions.  */
@@ -803,8 +803,8 @@ alpha_deal_with_atomic_sequence (struct frame_info *frame)
 	  immediate = (immediate ^ 0x400000) - 0x400000;
 
 	  if (bc_insn_count >= 1)
-	    return 0; /* More than one branch found, fallback 
+	    return NULL; /* More than one branch found, fallback 
-			 to the standard single-step code.  */
+			    to the standard single-step code.  */
 
 	  breaks[1] = loc + ALPHA_INSN_SIZE + immediate;
 
@@ -820,7 +820,7 @@ alpha_deal_with_atomic_sequence (struct frame_info *frame)
   /* Assume that the atomic sequence ends with a STL_C/STQ_C instruction.  */
   if (INSN_OPCODE (insn) != stl_c_opcode
       && INSN_OPCODE (insn) != stq_c_opcode)
-    return 0;
+    return NULL;
 
   closing_insn = loc;
   loc += ALPHA_INSN_SIZE;
@@ -835,11 +835,10 @@ alpha_deal_with_atomic_sequence (struct frame_info *frame)
 	  || (breaks[1] >= pc && breaks[1] <= closing_insn)))
     last_breakpoint = 0;
 
-  /* Effectively inserts the breakpoints.  */
   for (index = 0; index <= last_breakpoint; index++)
-    insert_single_step_breakpoint (gdbarch, aspace, breaks[index]);
+    VEC_safe_push (CORE_ADDR, next_pcs, breaks[index]);
 
-  return 1;
+  return next_pcs;
 }
 
 
@@ -1718,18 +1717,17 @@ alpha_next_pc (struct frame_info *frame, CORE_ADDR pc)
   return (pc + ALPHA_INSN_SIZE);
 }
 
-int
+VEC (CORE_ADDR) *
 alpha_software_single_step (struct frame_info *frame)
 {
   struct gdbarch *gdbarch = get_frame_arch (frame);
-  struct address_space *aspace = get_frame_address_space (frame);
+  CORE_ADDR pc;
-  CORE_ADDR pc, next_pc;
+  VEC (CORE_ADDR) *next_pcs = NULL;
 
   pc = get_frame_pc (frame);
-  next_pc = alpha_next_pc (frame, pc);
 
-  insert_single_step_breakpoint (gdbarch, aspace, next_pc);
+  VEC_safe_push (CORE_ADDR, next_pcs, alpha_next_pc (frame, pc));
-  return 1;
+  return next_pcs;
 }
 
 

gdb/alpha-tdep.h

@@ -103,7 +103,7 @@ struct gdbarch_tdep
 };
 
 extern unsigned int alpha_read_insn (struct gdbarch *gdbarch, CORE_ADDR pc);
-extern int alpha_software_single_step (struct frame_info *frame);
+extern VEC (CORE_ADDR) *alpha_software_single_step (struct frame_info *frame);
 extern CORE_ADDR alpha_after_prologue (CORE_ADDR pc);
 
 extern void alpha_mdebug_init_abi (struct gdbarch_info, struct gdbarch *);

gdb/arm-linux-tdep.c

@@ -921,12 +921,11 @@ arm_linux_get_next_pcs_syscall_next_pc (struct arm_get_next_pcs *self)
 
 /* Insert a single step breakpoint at the next executed instruction.  */
 
-static int
+static VEC (CORE_ADDR) *
 arm_linux_software_single_step (struct frame_info *frame)
 {
   struct regcache *regcache = get_current_regcache ();
   struct gdbarch *gdbarch = get_regcache_arch (regcache);
-  struct address_space *aspace = get_regcache_aspace (regcache);
   struct arm_get_next_pcs next_pcs_ctx;
   CORE_ADDR pc;
   int i;
@@ -936,7 +935,7 @@ arm_linux_software_single_step (struct frame_info *frame)
   /* If the target does have hardware single step, GDB doesn't have
      to bother software single step.  */
   if (target_can_do_single_step () == 1)
-    return 0;
+    return NULL;
 
   old_chain = make_cleanup (VEC_cleanup (CORE_ADDR), &next_pcs);
 
@@ -955,12 +954,9 @@ arm_linux_software_single_step (struct frame_info *frame)
       VEC_replace (CORE_ADDR, next_pcs, i, pc);
     }
 
-  for (i = 0; VEC_iterate (CORE_ADDR, next_pcs, i, pc); i++)
+  discard_cleanups (old_chain);
-    insert_single_step_breakpoint (gdbarch, aspace, pc);
 
-  do_cleanups (old_chain);
+  return next_pcs;
-
-  return 1;
 }
 
 /* Support for displaced stepping of Linux SVC instructions.  */

gdb/arm-tdep.c

@@ -6286,12 +6286,11 @@ arm_get_next_pcs_is_thumb (struct arm_get_next_pcs *self)
    single-step support.  We find the target of the coming instructions
    and breakpoint them.  */
 
-int
+VEC (CORE_ADDR) *
 arm_software_single_step (struct frame_info *frame)
 {
   struct regcache *regcache = get_current_regcache ();
   struct gdbarch *gdbarch = get_regcache_arch (regcache);
-  struct address_space *aspace = get_regcache_aspace (regcache);
   struct arm_get_next_pcs next_pcs_ctx;
   CORE_ADDR pc;
   int i;
@@ -6313,12 +6312,9 @@ arm_software_single_step (struct frame_info *frame)
       VEC_replace (CORE_ADDR, next_pcs, i, pc);
     }
 
-  for (i = 0; VEC_iterate (CORE_ADDR, next_pcs, i, pc); i++)
+  discard_cleanups (old_chain);
-    insert_single_step_breakpoint (gdbarch, aspace, pc);
 
-  do_cleanups (old_chain);
+  return next_pcs;
-
-  return 1;
 }
 
 /* Cleanup/copy SVC (SWI) instructions.  These two functions are overridden

gdb/arm-tdep.h

@@ -259,7 +259,7 @@ CORE_ADDR arm_get_next_pcs_addr_bits_remove (struct arm_get_next_pcs *self,
 
 int arm_get_next_pcs_is_thumb (struct arm_get_next_pcs *self);
 
-int arm_software_single_step (struct frame_info *);
+VEC (CORE_ADDR) *arm_software_single_step (struct frame_info *);
 int arm_is_thumb (struct regcache *regcache);
 int arm_frame_is_thumb (struct frame_info *frame);
 

gdb/breakpoint.c

@@ -15232,6 +15232,33 @@ insert_single_step_breakpoint (struct gdbarch *gdbarch,
   update_global_location_list (UGLL_INSERT);
 }
 
+/* Insert single step breakpoints according to the current state.  */
+
+int
+insert_single_step_breakpoints (struct gdbarch *gdbarch)
+{
+  struct frame_info *frame = get_current_frame ();
+  VEC (CORE_ADDR) * next_pcs;
+
+  next_pcs = gdbarch_software_single_step (gdbarch, frame);
+
+  if (next_pcs != NULL)
+    {
+      int i;
+      CORE_ADDR pc;
+      struct address_space *aspace = get_frame_address_space (frame);
+
+      for (i = 0; VEC_iterate (CORE_ADDR, next_pcs, i, pc); i++)
+	insert_single_step_breakpoint (gdbarch, aspace, pc);
+
+      VEC_free (CORE_ADDR, next_pcs);
+
+      return 1;
+    }
+  else
+    return 0;
+}
+
 /* See breakpoint.h.  */
 
 int

gdb/breakpoint.h

@@ -1530,6 +1530,12 @@ extern void delete_command (char *arg, int from_tty);
 extern void insert_single_step_breakpoint (struct gdbarch *,
 					   struct address_space *, 
 					   CORE_ADDR);
+
+/* Insert all software single step breakpoints for the current frame.
+   Return true if any software single step breakpoints are inserted,
+   otherwise, return false.  */
+extern int insert_single_step_breakpoints (struct gdbarch *);
+
 /* Check if any hardware watchpoints have triggered, according to the
    target.  */
 int watchpoints_triggered (struct target_waitstatus *);

gdb/cris-tdep.c

@@ -2060,12 +2060,12 @@ find_step_target (struct frame_info *frame, inst_env_type *inst_env)
    digs through the opcodes in order to find all possible targets.
    Either one ordinary target or two targets for branches may be found.  */
 
-static int
+static VEC (CORE_ADDR) *
 cris_software_single_step (struct frame_info *frame)
 {
   struct gdbarch *gdbarch = get_frame_arch (frame);
-  struct address_space *aspace = get_frame_address_space (frame);
   inst_env_type inst_env;
+  VEC (CORE_ADDR) *next_pcs = NULL;
 
   /* Analyse the present instruction environment and insert 
      breakpoints.  */
@@ -2082,18 +2082,19 @@ cris_software_single_step (struct frame_info *frame)
          and possibly another one for a branch, jump, etc.  */
       CORE_ADDR next_pc
 	= (CORE_ADDR) inst_env.reg[gdbarch_pc_regnum (gdbarch)];
-      insert_single_step_breakpoint (gdbarch, aspace, next_pc);
+
+      VEC_safe_push (CORE_ADDR, next_pcs, next_pc);
       if (inst_env.branch_found 
 	  && (CORE_ADDR) inst_env.branch_break_address != next_pc)
 	{
 	  CORE_ADDR branch_target_address
 		= (CORE_ADDR) inst_env.branch_break_address;
-	  insert_single_step_breakpoint (gdbarch,
+
-					 aspace, branch_target_address);
+	  VEC_safe_push (CORE_ADDR, next_pcs, branch_target_address);
 	}
     }
 
-  return 1;
+  return next_pcs;
 }
 
 /* Calculates the prefix value for quick offset addressing mode.  */

gdb/gdbarch.c

@@ -3165,7 +3165,7 @@ gdbarch_software_single_step_p (struct gdbarch *gdbarch)
   return gdbarch->software_single_step != NULL;
 }
 
-int
+VEC (CORE_ADDR) *
 gdbarch_software_single_step (struct gdbarch *gdbarch, struct frame_info *frame)
 {
   gdb_assert (gdbarch != NULL);

gdb/gdbarch.h

@@ -677,18 +677,19 @@ extern void set_gdbarch_addr_bits_remove (struct gdbarch *gdbarch, gdbarch_addr_
    FIXME/cagney/2001-01-18: The logic is backwards.  It should be asking if the
    target can single step.  If not, then implement single step using breakpoints.
   
-   A return value of 1 means that the software_single_step breakpoints
+   Return a vector of addresses on which the software single step
-   were inserted; 0 means they were not.  Multiple breakpoints may be
+   breakpoints should be inserted.  NULL means software single step is
-   inserted for some instructions such as conditional branch.  However,
+   not used.
-   each implementation must always evaluate the condition and only put
+   Multiple breakpoints may be inserted for some instructions such as
-   the breakpoint at the branch destination if the condition is true, so
+   conditional branch.  However, each implementation must always evaluate
-   that we ensure forward progress when stepping past a conditional
+   the condition and only put the breakpoint at the branch destination if
-   branch to self. */
+   the condition is true, so that we ensure forward progress when stepping
+   past a conditional branch to self. */
 
 extern int gdbarch_software_single_step_p (struct gdbarch *gdbarch);
 
-typedef int (gdbarch_software_single_step_ftype) (struct frame_info *frame);
+typedef VEC (CORE_ADDR) * (gdbarch_software_single_step_ftype) (struct frame_info *frame);
-extern int gdbarch_software_single_step (struct gdbarch *gdbarch, struct frame_info *frame);
+extern VEC (CORE_ADDR) * gdbarch_software_single_step (struct gdbarch *gdbarch, struct frame_info *frame);
 extern void set_gdbarch_software_single_step (struct gdbarch *gdbarch, gdbarch_software_single_step_ftype *software_single_step);
 
 /* Return non-zero if the processor is executing a delay slot and a

gdb/gdbarch.sh

@@ -626,14 +626,15 @@ m:CORE_ADDR:addr_bits_remove:CORE_ADDR addr:addr::core_addr_identity::0
 # FIXME/cagney/2001-01-18: The logic is backwards.  It should be asking if the
 # target can single step.  If not, then implement single step using breakpoints.
 #
-# A return value of 1 means that the software_single_step breakpoints
+# Return a vector of addresses on which the software single step
-# were inserted; 0 means they were not.  Multiple breakpoints may be
+# breakpoints should be inserted.  NULL means software single step is
-# inserted for some instructions such as conditional branch.  However,
+# not used.
-# each implementation must always evaluate the condition and only put
+# Multiple breakpoints may be inserted for some instructions such as
-# the breakpoint at the branch destination if the condition is true, so
+# conditional branch.  However, each implementation must always evaluate
-# that we ensure forward progress when stepping past a conditional
+# the condition and only put the breakpoint at the branch destination if
-# branch to self.
+# the condition is true, so that we ensure forward progress when stepping
-F:int:software_single_step:struct frame_info *frame:frame
+# past a conditional branch to self.
+F:VEC (CORE_ADDR) *:software_single_step:struct frame_info *frame:frame
 
 # Return non-zero if the processor is executing a delay slot and a
 # further single-step is needed before the instruction finishes.

gdb/infrun.c

@@ -2254,11 +2254,9 @@ maybe_software_singlestep (struct gdbarch *gdbarch, CORE_ADDR pc)
   int hw_step = 1;
 
   if (execution_direction == EXEC_FORWARD
-      && gdbarch_software_single_step_p (gdbarch)
+      && gdbarch_software_single_step_p (gdbarch))
-      && gdbarch_software_single_step (gdbarch, get_current_frame ()))
+    hw_step = !insert_single_step_breakpoints (gdbarch);
-    {
+
-      hw_step = 0;
-    }
   return hw_step;
 }
 

gdb/mips-tdep.c

@@ -3877,9 +3877,8 @@ mips_addr_bits_remove (struct gdbarch *gdbarch, CORE_ADDR addr)
 #define SC_OPCODE 0x38
 #define SCD_OPCODE 0x3c
 
-static int
+static VEC (CORE_ADDR) *
-mips_deal_with_atomic_sequence (struct gdbarch *gdbarch,
+mips_deal_with_atomic_sequence (struct gdbarch *gdbarch, CORE_ADDR pc)
- 				struct address_space *aspace, CORE_ADDR pc)
 {
   CORE_ADDR breaks[2] = {-1, -1};
   CORE_ADDR loc = pc;
@@ -3889,11 +3888,12 @@ mips_deal_with_atomic_sequence (struct gdbarch *gdbarch,
   int index;
   int last_breakpoint = 0; /* Defaults to 0 (no breakpoints placed).  */  
   const int atomic_sequence_length = 16; /* Instruction sequence length.  */
+  VEC (CORE_ADDR) *next_pcs = NULL;
 
   insn = mips_fetch_instruction (gdbarch, ISA_MIPS, loc, NULL);
   /* Assume all atomic sequences start with a ll/lld instruction.  */
   if (itype_op (insn) != LL_OPCODE && itype_op (insn) != LLD_OPCODE)
-    return 0;
+    return NULL;
 
   /* Assume that no atomic sequence is longer than "atomic_sequence_length" 
      instructions.  */
@@ -3957,7 +3957,7 @@ mips_deal_with_atomic_sequence (struct gdbarch *gdbarch,
 
   /* Assume that the atomic sequence ends with a sc/scd instruction.  */
   if (itype_op (insn) != SC_OPCODE && itype_op (insn) != SCD_OPCODE)
-    return 0;
+    return NULL;
 
   loc += MIPS_INSN32_SIZE;
 
@@ -3971,14 +3971,13 @@ mips_deal_with_atomic_sequence (struct gdbarch *gdbarch,
 
   /* Effectively inserts the breakpoints.  */
   for (index = 0; index <= last_breakpoint; index++)
-    insert_single_step_breakpoint (gdbarch, aspace, breaks[index]);
+    VEC_safe_push (CORE_ADDR, next_pcs, breaks[index]);
 
-  return 1;
+  return next_pcs;
 }
 
-static int
+static VEC (CORE_ADDR) *
 micromips_deal_with_atomic_sequence (struct gdbarch *gdbarch,
-				     struct address_space *aspace,
 				     CORE_ADDR pc)
 {
   const int atomic_sequence_length = 16; /* Instruction sequence length.  */
@@ -3991,16 +3990,17 @@ micromips_deal_with_atomic_sequence (struct gdbarch *gdbarch,
   ULONGEST insn;
   int insn_count;
   int index;
+  VEC (CORE_ADDR) *next_pcs = NULL;
 
   /* Assume all atomic sequences start with a ll/lld instruction.  */
   insn = mips_fetch_instruction (gdbarch, ISA_MICROMIPS, loc, NULL);
   if (micromips_op (insn) != 0x18)	/* POOL32C: bits 011000 */
-    return 0;
+    return NULL;
   loc += MIPS_INSN16_SIZE;
   insn <<= 16;
   insn |= mips_fetch_instruction (gdbarch, ISA_MICROMIPS, loc, NULL);
   if ((b12s4_op (insn) & 0xb) != 0x3)	/* LL, LLD: bits 011000 0x11 */
-    return 0;
+    return NULL;
   loc += MIPS_INSN16_SIZE;
 
   /* Assume all atomic sequences end with an sc/scd instruction.  Assume
@@ -4097,24 +4097,24 @@ micromips_deal_with_atomic_sequence (struct gdbarch *gdbarch,
 	          && b5s5_op (insn) != 0x18)
 				/* JRADDIUSP: bits 010001 11000 */
 	        break;
-	      return 0; /* Fall back to the standard single-step code. */
+	      return NULL; /* Fall back to the standard single-step code. */
 
 	    case 0x33: /* B16: bits 110011 */
-	      return 0; /* Fall back to the standard single-step code. */
+	      return NULL; /* Fall back to the standard single-step code. */
 	    }
 	  break;
 	}
       if (is_branch)
 	{
 	  if (last_breakpoint >= 1)
-	    return 0; /* More than one branch found, fallback to the
+	    return NULL; /* More than one branch found, fallback to the
 			 standard single-step code.  */
 	  breaks[1] = branch_bp;
 	  last_breakpoint++;
 	}
     }
   if (!sc_found)
-    return 0;
+    return NULL;
 
   /* Insert a breakpoint right after the end of the atomic sequence.  */
   breaks[0] = loc;
@@ -4126,21 +4126,20 @@ micromips_deal_with_atomic_sequence (struct gdbarch *gdbarch,
 
   /* Effectively inserts the breakpoints.  */
   for (index = 0; index <= last_breakpoint; index++)
-    insert_single_step_breakpoint (gdbarch, aspace, breaks[index]);
+    VEC_safe_push (CORE_ADDR, next_pcs, breaks[index]);
 
-  return 1;
+  return next_pcs;
 }
 
-static int
+static VEC (CORE_ADDR) *
-deal_with_atomic_sequence (struct gdbarch *gdbarch,
+deal_with_atomic_sequence (struct gdbarch *gdbarch, CORE_ADDR pc)
-			   struct address_space *aspace, CORE_ADDR pc)
 {
   if (mips_pc_is_mips (pc))
-    return mips_deal_with_atomic_sequence (gdbarch, aspace, pc);
+    return mips_deal_with_atomic_sequence (gdbarch, pc);
   else if (mips_pc_is_micromips (gdbarch, pc))
-    return micromips_deal_with_atomic_sequence (gdbarch, aspace, pc);
+    return micromips_deal_with_atomic_sequence (gdbarch, pc);
   else
-    return 0;
+    return NULL;
 }
 
 /* mips_software_single_step() is called just before we want to resume
@@ -4148,21 +4147,22 @@ deal_with_atomic_sequence (struct gdbarch *gdbarch,
    or kernel single-step support (MIPS on GNU/Linux for example).  We find
    the target of the coming instruction and breakpoint it.  */
 
-int
+VEC (CORE_ADDR) *
 mips_software_single_step (struct frame_info *frame)
 {
   struct gdbarch *gdbarch = get_frame_arch (frame);
-  struct address_space *aspace = get_frame_address_space (frame);
   CORE_ADDR pc, next_pc;
+  VEC (CORE_ADDR) *next_pcs;
 
   pc = get_frame_pc (frame);
-  if (deal_with_atomic_sequence (gdbarch, aspace, pc))
+  next_pcs = deal_with_atomic_sequence (gdbarch, pc);
-    return 1;
+  if (next_pcs != NULL)
+    return next_pcs;
 
   next_pc = mips_next_pc (frame, pc);
 
-  insert_single_step_breakpoint (gdbarch, aspace, next_pc);
+  VEC_safe_push (CORE_ADDR, next_pcs, next_pc);
-  return 1;
+  return next_pcs;
 }
 
 /* Test whether the PC points to the return instruction at the

gdb/mips-tdep.h

@@ -154,7 +154,7 @@ enum
 };
 
 /* Single step based on where the current instruction will take us.  */
-extern int mips_software_single_step (struct frame_info *frame);
+extern VEC (CORE_ADDR) *mips_software_single_step (struct frame_info *frame);
 
 /* Strip the ISA (compression) bit off from ADDR.  */
 extern CORE_ADDR mips_unmake_compact_addr (CORE_ADDR addr);

gdb/moxie-tdep.c

@@ -299,11 +299,10 @@ moxie_process_readu (CORE_ADDR addr, gdb_byte *buf,
 
 /* Insert a single step breakpoint.  */
 
-static int
+static VEC (CORE_ADDR) *
 moxie_software_single_step (struct frame_info *frame)
 {
   struct gdbarch *gdbarch = get_frame_arch (frame);
-  struct address_space *aspace = get_frame_address_space (frame);
   CORE_ADDR addr;
   gdb_byte buf[4];
   uint16_t inst;
@@ -311,6 +310,7 @@ moxie_software_single_step (struct frame_info *frame)
   ULONGEST fp;
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   struct regcache *regcache = get_current_regcache ();
+  VEC (CORE_ADDR) *next_pcs = NULL;
 
   addr = get_frame_pc (frame);
 
@@ -338,8 +338,9 @@ moxie_software_single_step (struct frame_info *frame)
 	    case 0x09: /* bleu */
 	      /* Insert breaks on both branches, because we can't currently tell
 		 which way things will go.  */
-	      insert_single_step_breakpoint (gdbarch, aspace, addr + 2);
+	      VEC_safe_push (CORE_ADDR, next_pcs, addr + 2);
-	      insert_single_step_breakpoint (gdbarch, aspace, addr + 2 + INST2OFFSET(inst));
+	      VEC_safe_push (CORE_ADDR, next_pcs,
+			     addr + 2 + INST2OFFSET(inst));
 	      break;
 	    default:
 	      {
@@ -351,7 +352,7 @@ moxie_software_single_step (struct frame_info *frame)
       else
 	{
 	  /* This is a Form 2 instruction.  They are all 16 bits.  */
-	  insert_single_step_breakpoint (gdbarch, aspace, addr + 2);
+	  VEC_safe_push (CORE_ADDR, next_pcs, addr + 2);
 	}
     }
   else
@@ -398,7 +399,7 @@ moxie_software_single_step (struct frame_info *frame)
 	case 0x32: /* udiv.l */
 	case 0x33: /* mod.l */
 	case 0x34: /* umod.l */
-	  insert_single_step_breakpoint (gdbarch, aspace, addr + 2);
+	  VEC_safe_push (CORE_ADDR, next_pcs, addr + 2);
 	  break;
 
 	  /* 32-bit instructions.  */
@@ -408,7 +409,7 @@ moxie_software_single_step (struct frame_info *frame)
 	case 0x37: /* sto.b */
 	case 0x38: /* ldo.s */
 	case 0x39: /* sto.s */
-	  insert_single_step_breakpoint (gdbarch, aspace, addr + 4);
+	  VEC_safe_push (CORE_ADDR, next_pcs, addr + 4);
 	  break;
 
 	  /* 48-bit instructions.  */
@@ -421,32 +422,27 @@ moxie_software_single_step (struct frame_info *frame)
 	case 0x20: /* ldi.s (immediate) */
 	case 0x22: /* lda.s */
 	case 0x24: /* sta.s */
-	  insert_single_step_breakpoint (gdbarch, aspace, addr + 6);
+	  VEC_safe_push (CORE_ADDR, next_pcs, addr + 6);
 	  break;
 
 	  /* Control flow instructions.	 */
 	case 0x03: /* jsra */
 	case 0x1a: /* jmpa */
-	  insert_single_step_breakpoint (gdbarch, aspace,
+	  VEC_safe_push (CORE_ADDR, next_pcs,
-					 moxie_process_readu (addr + 2,
+			 moxie_process_readu (addr + 2, buf, 4, byte_order));
-							      buf, 4,
-							      byte_order));
 	  break;
 
 	case 0x04: /* ret */
 	  regcache_cooked_read_unsigned (regcache, MOXIE_FP_REGNUM, &fp);
-	  insert_single_step_breakpoint (gdbarch, aspace,
+	  VEC_safe_push (CORE_ADDR, next_pcs,
-					 moxie_process_readu (fp + 4,
+			 moxie_process_readu (fp + 4, buf, 4, byte_order));
-							      buf, 4,
-							      byte_order));
 	  break;
 
 	case 0x19: /* jsr */
 	case 0x25: /* jmp */
 	  regcache_raw_read (regcache,
 			     (inst >> 4) & 0xf, (gdb_byte *) & tmpu32);
-	  insert_single_step_breakpoint (gdbarch, aspace,
+	  VEC_safe_push (CORE_ADDR, next_pcs, tmpu32);
-					 tmpu32);
 	  break;
 
 	case 0x30: /* swi */
@@ -456,7 +452,7 @@ moxie_software_single_step (struct frame_info *frame)
 	}
     }
 
-  return 1;
+  return next_pcs;
 }
 
 /* Implement the "read_pc" gdbarch method.  */

gdb/nios2-tdep.c

@@ -2219,16 +2219,16 @@ nios2_get_next_pc (struct frame_info *frame, CORE_ADDR pc)
 
 /* Implement the software_single_step gdbarch method.  */
 
-static int
+static VEC (CORE_ADDR) *
 nios2_software_single_step (struct frame_info *frame)
 {
   struct gdbarch *gdbarch = get_frame_arch (frame);
-  struct address_space *aspace = get_frame_address_space (frame);
   CORE_ADDR next_pc = nios2_get_next_pc (frame, get_frame_pc (frame));
+  VEC (CORE_ADDR) *next_pcs = NULL;
 
-  insert_single_step_breakpoint (gdbarch, aspace, next_pc);
+  VEC_safe_push (CORE_ADDR, next_pcs, next_pc);
 
-  return 1;
+  return next_pcs;
 }
 
 /* Implement the get_longjump_target gdbarch method.  */

gdb/ppc-tdep.h

@@ -76,7 +76,7 @@ int ppc_altivec_support_p (struct gdbarch *gdbarch);
 /* Return non-zero if the architecture described by GDBARCH has
    VSX registers (vsr0 --- vsr63).  */
 int vsx_support_p (struct gdbarch *gdbarch);
-int ppc_deal_with_atomic_sequence (struct frame_info *frame);
+VEC (CORE_ADDR) *ppc_deal_with_atomic_sequence (struct frame_info *frame);
 
 
 /* Register set description.  */

gdb/record-full.c

@@ -976,17 +976,7 @@ record_full_resume (struct target_ops *ops, ptid_t ptid, int step,
                   record_full_resume_step = 1;
                 }
               else
-                {
+		step = !insert_single_step_breakpoints (gdbarch);
-                  /* This is a continue.
-                     Try to insert a soft single step breakpoint.  */
-                  if (!gdbarch_software_single_step (gdbarch,
-                                                     get_current_frame ()))
-                    {
-                      /* This system don't want use soft single step.
-                         Use hard sigle step.  */
-                      step = 1;
-                    }
-                }
             }
         }
 
@@ -1168,9 +1158,9 @@ record_full_wait_1 (struct target_ops *ops,
 			     If insert success, set step to 0.  */
 			  set_executing (inferior_ptid, 0);
 			  reinit_frame_cache ();
-			  if (gdbarch_software_single_step (gdbarch,
+
-                                                            get_current_frame ()))
+			  step = !insert_single_step_breakpoints (gdbarch);
-			    step = 0;
+
 			  set_executing (inferior_ptid, 1);
 			}
 

gdb/rs6000-aix-tdep.c

@@ -669,7 +669,7 @@ branch_dest (struct frame_info *frame, int opcode, int instr,
 
 /* AIX does not support PT_STEP.  Simulate it.  */
 
-static int
+static VEC (CORE_ADDR) *
 rs6000_software_single_step (struct frame_info *frame)
 {
   struct gdbarch *gdbarch = get_frame_arch (frame);
@@ -679,13 +679,15 @@ rs6000_software_single_step (struct frame_info *frame)
   CORE_ADDR loc;
   CORE_ADDR breaks[2];
   int opcode;
+  VEC (CORE_ADDR) *next_pcs;
 
   loc = get_frame_pc (frame);
 
   insn = read_memory_integer (loc, 4, byte_order);
 
-  if (ppc_deal_with_atomic_sequence (frame))
+  next_pcs = ppc_deal_with_atomic_sequence (frame);
-    return 1;
+  if (next_pcs != NULL)
+    return next_pcs;
   
   breaks[0] = loc + PPC_INSN_SIZE;
   opcode = insn >> 26;
@@ -700,12 +702,12 @@ rs6000_software_single_step (struct frame_info *frame)
       /* ignore invalid breakpoint.  */
       if (breaks[ii] == -1)
 	continue;
-      insert_single_step_breakpoint (gdbarch, aspace, breaks[ii]);
+      VEC_safe_push (CORE_ADDR, next_pcs, breaks[ii]);
     }
 
   errno = 0;			/* FIXME, don't ignore errors!  */
   /* What errors?  {read,write}_memory call error().  */
-  return 1;
+  return next_pcs;
 }
 
 /* Implement the "auto_wide_charset" gdbarch method for this platform.  */

gdb/rs6000-tdep.c

@@ -1143,7 +1143,7 @@ ppc_displaced_step_hw_singlestep (struct gdbarch *gdbarch,
    is found, attempt to step through it.  A breakpoint is placed at the end of 
    the sequence.  */
 
-int 
+VEC (CORE_ADDR) *
 ppc_deal_with_atomic_sequence (struct frame_info *frame)
 {
   struct gdbarch *gdbarch = get_frame_arch (frame);
@@ -1159,11 +1159,12 @@ ppc_deal_with_atomic_sequence (struct frame_info *frame)
   int last_breakpoint = 0; /* Defaults to 0 (no breakpoints placed).  */  
   const int atomic_sequence_length = 16; /* Instruction sequence length.  */
   int bc_insn_count = 0; /* Conditional branch instruction count.  */
+  VEC (CORE_ADDR) *next_pcs = NULL;
 
   /* Assume all atomic sequences start with a lwarx/ldarx instruction.  */
   if ((insn & LWARX_MASK) != LWARX_INSTRUCTION
       && (insn & LWARX_MASK) != LDARX_INSTRUCTION)
-    return 0;
+    return NULL;
 
   /* Assume that no atomic sequence is longer than "atomic_sequence_length" 
      instructions.  */
@@ -1201,7 +1202,7 @@ ppc_deal_with_atomic_sequence (struct frame_info *frame)
   /* Assume that the atomic sequence ends with a stwcx/stdcx instruction.  */
   if ((insn & STWCX_MASK) != STWCX_INSTRUCTION
       && (insn & STWCX_MASK) != STDCX_INSTRUCTION)
-    return 0;
+    return NULL;
 
   closing_insn = loc;
   loc += PPC_INSN_SIZE;
@@ -1217,11 +1218,10 @@ ppc_deal_with_atomic_sequence (struct frame_info *frame)
 	  || (breaks[1] >= pc && breaks[1] <= closing_insn)))
     last_breakpoint = 0;
 
-  /* Effectively inserts the breakpoints.  */
   for (index = 0; index <= last_breakpoint; index++)
-    insert_single_step_breakpoint (gdbarch, aspace, breaks[index]);
+    VEC_safe_push (CORE_ADDR, next_pcs, breaks[index]);
 
-  return 1;
+  return next_pcs;
 }
 
 

gdb/s390-linux-tdep.c

@@ -722,7 +722,7 @@ s390_is_partial_instruction (struct gdbarch *gdbarch, CORE_ADDR loc, int *len)
    process about 4kiB of it each time, leading to O(n**2) memory and time
    complexity.  */
 
-static int
+static VEC (CORE_ADDR) *
 s390_software_single_step (struct frame_info *frame)
 {
   struct gdbarch *gdbarch = get_frame_arch (frame);
@@ -731,33 +731,33 @@ s390_software_single_step (struct frame_info *frame)
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   int len;
   uint16_t insn;
+  VEC (CORE_ADDR) *next_pcs = NULL;
 
   /* Special handling only if recording.  */
   if (!record_full_is_used ())
-    return 0;
+    return NULL;
 
   /* First, match a partial instruction.  */
   if (!s390_is_partial_instruction (gdbarch, loc, &len))
-    return 0;
+    return NULL;
 
   loc += len;
 
   /* Second, look for a branch back to it.  */
   insn = read_memory_integer (loc, 2, byte_order);
   if (insn != 0xa714) /* BRC with mask 1 */
-    return 0;
+    return NULL;
 
   insn = read_memory_integer (loc + 2, 2, byte_order);
   if (insn != (uint16_t) -(len / 2))
-    return 0;
+    return NULL;
 
   loc += 4;
 
   /* Found it, step past the whole thing.  */
+  VEC_safe_push (CORE_ADDR, next_pcs, loc);
 
-  insert_single_step_breakpoint (gdbarch, aspace, loc);
+  return next_pcs;
-
-  return 1;
 }
 
 static int

gdb/sparc-tdep.c

@@ -1599,7 +1599,7 @@ sparc_step_trap (struct frame_info *frame, unsigned long insn)
   return 0;
 }
 
-static int
+static VEC (CORE_ADDR) *
 sparc_software_single_step (struct frame_info *frame)
 {
   struct gdbarch *arch = get_frame_arch (frame);
@@ -1608,6 +1608,7 @@ sparc_software_single_step (struct frame_info *frame)
   CORE_ADDR npc, nnpc;
 
   CORE_ADDR pc, orig_npc;
+  VEC (CORE_ADDR) *next_pcs = NULL;
 
   pc = get_frame_register_unsigned (frame, tdep->pc_regnum);
   orig_npc = npc = get_frame_register_unsigned (frame, tdep->npc_regnum);
@@ -1615,10 +1616,10 @@ sparc_software_single_step (struct frame_info *frame)
   /* Analyze the instruction at PC.  */
   nnpc = sparc_analyze_control_transfer (frame, pc, &npc);
   if (npc != 0)
-    insert_single_step_breakpoint (arch, aspace, npc);
+    VEC_safe_push (CORE_ADDR, next_pcs, npc);
 
   if (nnpc != 0)
-    insert_single_step_breakpoint (arch, aspace, nnpc);
+    VEC_safe_push (CORE_ADDR, next_pcs, nnpc);
 
   /* Assert that we have set at least one breakpoint, and that
      they're not set at the same spot - unless we're going
@@ -1626,7 +1627,7 @@ sparc_software_single_step (struct frame_info *frame)
   gdb_assert (npc != 0 || nnpc != 0 || orig_npc == 0);
   gdb_assert (nnpc != npc || orig_npc == 0);
 
-  return 1;
+  return next_pcs;
 }
 
 static void

gdb/spu-tdep.c

@@ -1610,17 +1610,17 @@ spu_memory_remove_breakpoint (struct gdbarch *gdbarch,
 
 /* Software single-stepping support.  */
 
-static int
+static VEC (CORE_ADDR) *
 spu_software_single_step (struct frame_info *frame)
 {
   struct gdbarch *gdbarch = get_frame_arch (frame);
-  struct address_space *aspace = get_frame_address_space (frame);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   CORE_ADDR pc, next_pc;
   unsigned int insn;
   int offset, reg;
   gdb_byte buf[4];
   ULONGEST lslr;
+  VEC (CORE_ADDR) *next_pcs = NULL;
 
   pc = get_frame_pc (frame);
 
@@ -1643,8 +1643,7 @@ spu_software_single_step (struct frame_info *frame)
   else
     next_pc = (SPUADDR_ADDR (pc) + 4) & lslr;
 
-  insert_single_step_breakpoint (gdbarch,
+  VEC_safe_push (CORE_ADDR, next_pcs, SPUADDR (SPUADDR_SPU (pc), next_pc));
-				 aspace, SPUADDR (SPUADDR_SPU (pc), next_pc));
 
   if (is_branch (insn, &offset, &reg))
     {
@@ -1674,11 +1673,11 @@ spu_software_single_step (struct frame_info *frame)
 
       target = target & lslr;
       if (target != next_pc)
-	insert_single_step_breakpoint (gdbarch, aspace,
+	VEC_safe_push (CORE_ADDR, next_pcs, SPUADDR (SPUADDR_SPU (pc),
-				       SPUADDR (SPUADDR_SPU (pc), target));
+						     target));
     }
 
-  return 1;
+  return next_pcs;
 }
 
 

gdb/tic6x-tdep.c

@@ -699,16 +699,15 @@ tic6x_get_next_pc (struct frame_info *frame, CORE_ADDR pc)
 
 /* This is the implementation of gdbarch method software_single_step.  */
 
-static int
+static VEC (CORE_ADDR) *
 tic6x_software_single_step (struct frame_info *frame)
 {
-  struct gdbarch *gdbarch = get_frame_arch (frame);
-  struct address_space *aspace = get_frame_address_space (frame);
   CORE_ADDR next_pc = tic6x_get_next_pc (frame, get_frame_pc (frame));
+  VEC (CORE_ADDR) *next_pcs = NULL;
 
-  insert_single_step_breakpoint (gdbarch, aspace, next_pc);
+  VEC_safe_push (CORE_ADDR, next_pcs, next_pc);
 
-  return 1;
+  return next_pcs;
 }
 
 /* This is the implementation of gdbarch method frame_align.  */